TechnologyQuarterly

Laser weapons pack some heat

Taking a shine to solar lamps

What comes after fl ash memory?

September 1st 2012

Look, no handsSelf-driving cars are just around the corner

TQCOV-September-2012.indd 1 20/08/2012 15:54

Monitor

1 Robot minesweeping,gas-guzzling paint,water-repellent materials,regulating bionics, infra-redsolar panels, storing medicinesusing silk, social mobilisation,carbon monoxide as a drug andhigh-tech toilets

Di�erence engine

7 Lost in cyberspaceWill historians of the future wishmore web pages had been kept?

Energy weapons

8 Zap, crackle and popMilitary lasers are coming, butthey are hardly super-weapons

Solar lighting

10 Lighting the wayNew technology and businessmodels could doom kerosene

Inside story

12 Look, no handsDriverless cars are just aroundthe corner. How do they work?

Phase-change memory

15 Altered statesThe technology that will soonstore your music and photos

Brain scan

17 Knight in digital armourA pro�le of Chris Soghoian,defender of personal privacy

The Economist Technology Quarterly September 1st 2012 Monitor 1

FOR decades navies have employedhuman divers, dolphins and sea lions

to search for explosives attached to thehulls of warships by a scuba-diving ene-my. Although these mine-�nding tacticswork, they are less than ideal. Divers canbe killed or injured and marine mammalsare extremely costly to maintain on a boat.Mines are also getting smaller and harderto detect. The idea of using aquatic robotsto search for the mines instead is alluring,but it is di�cult to teach machines how tonavigate around hulls without crashinginto them or getting lost. Franz Hover andBrendan Englot at the MassachusettsInstitute of Technology (MIT) have comeup with a way to improve things by usinga two-step process.

Programming robots to scan hullswould be relatively easy if limpet mineswere still as large as watermelons. Therobot would simply be told to maintain asafe working distance and swim back andforth, using its sonar scanners to generatean image of the hull’s topography. If theresulting image perfectly matched that ofa clean hull stored in the robot’s memory,it could be safely assumed that there wereno mines attached. If not it could raise analarm. Yet nowadays mines can be as tinyas a mobile phone. Such a mine might notblast a hole in the hull, but if carefullyplaced it could disable a ship’s propellers.

The problem, then, is one of de�nition.Sonar scans done at a safe distance of 10metres create a rough image known as adata-point cloud. But this lacks the detailnecessary to spot small explosive charges.The addition of video cameras may not domuch to help, because harbour waters areoften murky. To work around these pro-blems, Dr Hover came up with the idea ofusing the data-point cloud not to spotmines, but as a guide to help the robot takea closer look at the hull.

With this in mind Dr Hover and MrEnglot, along with a team of colleagues,used a robot known as the HoveringAutonomous Underwater Vehicle(HAUV), which was developed at MIT andhas since been commercialised by a com-pany called Blue�n Robotics. The robotwas programmed to create a data-pointcloud using a traditional sonar scan. Thisgrainy image was then processed by analgorithm designed to connect the datapoints and create a three-dimensional gridmap that the HAUV could use as a guidefor moving in closer, to perform a secondscan at a distance of one metre. (In theimage above, the robot is shown in yellow,and the range of its sonar scanner in red.)

Early results are promising. Letting thenewly programmed HAUV loose on theCurtiss, a 183-metre military-support shipin San Diego, and the Seneca, an 82-metre

Sweeping below deck

Robotics: A marine robot uses sonar to scan for tiny limpet mines attached toa ship’s hull. But military dolphins and sea lions are not out of a job just yet

On the coverCars that can drivethemselves are closer thanyou might think. Cruise-control, lane-keeping andself-parking systems aregetting smarter, and a fewfully autonomous vehicles arealready on the roads. Thiscould transform car design,rede�ne car ownership anda�ect city planning, page 12

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2 Monitor The Economist Technology Quarterly September 1st 2012

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cutter in Boston, showed that a robot cando the job. First, a scan at a range of 8metres generated a 3D model. This wasthen used as a guide for a close-up in-spection of the tight and tucked-awayspaces between the propeller, shafting,rudder and hull. �If there is a need to seeeverything on the hull in great detail, therobots win big,� says Dr Hover. Blue�n hasa $30m contract from the US Navy todevelop the HAUV with MIT.

Robots are not about to take over allhull examinations, however. The HAUV

was less successful at carrying out its taskwhen working in strong or complex cur-rents of the sort that trained marine mam-mals would simply ignore. So in someconditions the dolphins and sea lions willcontinue to have a clear advantage�for thetime being, at least. 7

is usually done by sloshing it with a sol-ution of hydrogen peroxide. This works,but lugging the stu� around is a nuisance�and so is disposing of it once it has beenused. Britain’s Defence Science and Tech-nology Laboratory, working in collabora-tion with AkzoNobel, a maker of paintand specialty chemicals, proposes doingthe job with a fancy sort of paint.

As is often the case with paint jobs, thenew anti-chemical-weapon paint needsan undercoat and a top coat. The top coatcontains silica gel, an absorbent materialthat can suck up nerve gas and stop itgetting inside a vehicle. This upper layer isavailable in standard camou�age colours,such as yellow (for deserts) and green (forjungles). The undercoat is made of a po-lymer that acts like the glue on a Post-itnote. It is, in other words, sticky enough tohold the top coat in place, but can be easilypeeled away. If a vehicle gets contaminat-ed its paint can be quickly scraped o� anda new top coat applied in its place.

The next stage, currently still in thelaboratory, is to develop coatings thatchange colour when they absorb toxicchemicals, thus alerting soldiers that theyare under chemical attack. The details aresecret, but a system which responds tomustard gas has been devised, and othersare under development. After that, theplan is to produce a coating that not onlyabsorbs noxious chemicals, but neutral-ises them. A group of researchers at theUniversity of Vermont, led by ChristopherLandry, have already managed to combinesilica gel with a vanadium catalyst tocreate a mixture that oxidises mustard gas,rendering it harmless.

In the future, then, military paint willnot only hide vehicles from prying eyes�itwill also help protect soldiers from one ofthe most feared forms of attack. WhatWilfred Owen called the �ecstasy of fum-bling� that follows the cry of �Gas!� maybecome a little less panic-stricken. 7

A good kind ofgas-guzzling

Military technology: New kinds ofpaint for military vehicles candetect, absorb and neutralise gasesin a chemical-weapon attack

ALTHOUGH there has been no large-scale use of chemical weapons since

the Iran-Iraq war in the 1980s, soldiersneed to be prepared for the threat. Part ofthat preparation means being able todecontaminate people and equipmentthat have been subject to attack.

The suits and masks worn by soldierscan, if necessary, be thrown away onceused, but heavier and more expensiveequipment, such as vehicles, cannot betreated in such a cavalier fashion. Instead,it needs to be cleaned. At the moment, that

Encouraginghydrophobia

Materials science: A clever chemicaltrick o�ers a way to make fabricsmore water-repellent and harderwearing at the same time

WHEN it comes to repelling gunk, carwax and Te�on are among the best

materials available. But they could bebetter. A good measure of their lack ofstickiness is their �water contact angle��away of measuring how e�ectively thematerial repels water. For car wax it is 90°and for Te�on, 95°. The higher the angle,the more repellent the surface is�and thecleaner it stays. As anyone with a car or anon-stick frying pan knows, however, themicroscopic wax or Te�on layers gradual-ly wear away, and their protective abilityis lost. So �nding a way to make the layersbond together more strongly would alsokeep surfaces cleaner. Tong Lin, a chemistat Deakin University in Australia, thinkshe has found a trick that can both increasethe contact angle and improve resilience,using an idea familiar from basic chem-istry: the covalent bond.

Normally the layers of Te�on, car waxand substances like them are held togetherby ionic bonds. These form when one ormore electrons leap from one atom toanother in order to ful�l a requirement,deep in the heart of quantum theory, thatsuch particles pair up if they can, so thattheir spins cancel out. The atom that gainsan electron thus acquires a negativecharge, and the atom that loses an electrona positive charge. Because unlike chargesattract, the charged atoms stick together.

The problem with ionic bonds is thatthey are easily disrupted by acids andbases�chemicals which, respectively, addelectrons to, and take them from, othermolecules. In a covalent bond, by contrast,electron pairs are formed when atomsshare electrons, rather than transferringthem. This makes covalent bonds lesssusceptible to disruption.

Accordingly, Dr Lin and his colleaguestried to build up covalent bonds betweenthe layers of a water-repellent, or hydro-phobic, material called cellulose acetatebutyrate, which is used to make water-resistant fabrics. In doing so they not onlymade it acid- and base-proof, they alsoimproved its gunk-resistance.

They performed this trick, as theyexplain in the journal Langmuir, using asubstance called phenyl azido, whichreadily forms covalent bonds with itsneighbours when exposed to ultravioletlight. They immersed �lms made of cellu-

lose acetate butyrate in solutions of phe-nyl azido and silica (which is positivelycharged) and phenyl azido and poly-allylamine hydrochloride (which is nega-tively charged). They spread these �lms inalternate layers on top of sheets of cottonfabric and exposed the sandwich to ultra-violet light for 30 minutes to bond thelayers covalently. Then they tested itsability to repel water, acids and bases.

The new material was amazinglyhydrophobic. Its contact angle was 154° outof a possible maximum of 180°. (Standardcellulose acetate butyrate has a contactangle of 76°.) The material was also im-pressively robust. Even after being dunkedfor 95 hours in hydrochloric acid or 44hours in sodium hydroxide it maintaineda contact angle of greater than 150°. It alsodid so after enduring 50 cycles in one ofthe most hostile environments known onthe planet: a domestic washing machine.

You would not, it is true, want celluloseacetate butyrate on either your car or yourfrying pan. But it would o�er a way tomake better raincoats, and is also a proofof principle. If fabrics can be made morewater-repellent in this way, then perhapsother materials can be, too. 7

SPEAKING at a conference organised byThe Economist earlier this year, Hugh

Herr, a roboticist at the MassachusettsInstitute of Technology, described dis-abilities as conditions that persist �be-cause of poor technology� and made thebold claim that during the 21st centurydisability would be largely eliminated.What gave his words added force was thathalf way through his speech, after tenminutes of strolling around the stage, heunexpectedly pulled up his trouser legs toreveal his bionic legs, and then danced alittle jig. In future, he suggested, peoplemight choose to replace an arthritic, pain-ful limb with a fully functional roboticone. �Why wouldn’t you replace it?� heasked. �We’re going to see a lot of unusualsituations like that.�

It is precisely to consider these sorts ofsituations, and the legal and ethical co-nundrums they will pose, that a newresearch project was launched in March. Isa prosthetic legally part of your body?When is it appropriate to amputate a limband replace it with a robotic one? What are

for their part, are considering future tech-nologies, such as embedded devices thatenhance the senses or add new ones, andimplants that improve memory or allowmessages to be sent or devices to be con-trolled using thought alone. Such devicesmight initially be used to overcome dis-ability, but could also be used to augmentand increase the performance of the able-bodied. Indeed, the main ethical questionsposed by the integration of technologyinto the body concern the augmentation ofexisting capabilities, rather than the resto-ration of missing or lost ones, says PericleSalvini of the SSSA.

Implants may also raise new questionsabout privacy and guardianship. Already,brain-computer interfaces can enabletotally paralysed people with locked-insyndrome to communicate. But what legalstatus should be attributed to their com-munications? And does a person commu-nicating using such a device still require aguardian to make legal and medical deci-sions on his or her behalf?

Regulators must tread carefully. NoelSharkey, a computer scientist at the Univer-sity of She�eld, observes that overly rigidregulations might sti�e innovation. But alack of legal clarity leaves device-makers,doctors, patients and insurers in the dark.The RoboLaw researchers hope to squarethis circle when they deliver their �ndingsin 2014. So far, though, they seem to havemore questions than answers. 7

You, robot?

Technology and regulation: Aresearch project considers how thelaw should deal with technologiesthat blur man and machine

the legal rights of a person with �lockedin� syndrome who communicates via abrain-computer interface? Do brain im-plants and body-enhancement devicesrequire changes to the de�nition of dis-ability? The RoboLaw project is an e�ort toanticipate such quandaries and work outwhere and how legal frameworks mightneed to be changed as the technology ofbionics and neural interfaces improves.Funded to the tune of �1.9m ($2.3m), ofwhich �1.4m comes from the EuropeanCommission, it brings together expertsfrom engineering, law, regulation, philoso-phy and human enhancement.

Erica Palmerini of the Scuola SuperioreSant’Anna (SSSA), in Pisa, Italy, which isdirecting the project, says there is an �ur-gent need� for regulation and legislationto manage new technologies like prosthet-ics and implants. If you are dependent ona robotic wheelchair for mobility, forexample, does the wheelchair count aspart of your body? Linda MacDonaldGlenn, an American lawyer and bioeth-icist, thinks it does. Ms Glenn (who is notinvolved in the RoboLaw project) persuad-ed an initially sceptical insurance �rm thata �mobility assistance device� damagedby airline sta� was more than her client’spersonal property, it was an extension ofhis physical body. The airline settled out ofcourt. Similarly, Neil Harbisson, a colour-blind artist who wears an �eyeborg�adevice that enables him to �hear� col-ourssuccessfully argued with Britishauthorities that he should be allowed towear the device in his passport picture, onthe basis that it is part of his body. Theseare just early examples of the sorts of legalproblems to come.

Each of the institutions participating inthe RoboLaw project will concentrate on adi�erent area. Specialists in technologylaw at the Tilburg Institute for Law, Tech-nology, and Society in the Netherlands aredrawing up a taxonomy of robotic devicesand matching them against existing legalterminology to identify potential legalproblems relating to the de�nitions ofhuman autonomy, disability, normalcyand equality. For example, if robotic de-vices can restore sight or mobility, it maybe necessary to rede�ne what disabilityiswhich might, in turn, con�ict with theassumptions on which existing disability-rights legislation is based.

Philosophers at the Humboldt Univer-sity of Berlin, meanwhile, are exploringthe various ways in which robotic tech-nologies challenge the notion of what itmeans to be human. To what extent is itde�ned by having a body of a particularshape, or by cultural factors? Technologiessuch as exoskeletons that provide in-creased strength and implants that im-prove memory will put both de�nitionsunder pressure. Human-enhancementresearchers at the University of Reading,

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The Economist Technology Quarterly September 1st 2012 Monitor 3

4 Monitor The Economist Technology Quarterly September 1st 2012

SOLAR panels get better and cheaperwith every passing year. In one way,

though, they are still quite primitive. Theywork only with light in the visible part ofthe spectrum. Yet 40% of the solar energythat reaches the Earth is in, or very closeto, the infra-red. A cell that could harvestsuch radiation would be a boon to thesolar-power business, but building onehas proved di�cult. Now, though, as theyreport in Advanced Materials, a group ofresearchers led by Michael Strano at theMassachusetts Institute of Technologyhave worked out how to do it.

When sunlight strikes the silicon atomsin an ordinary solar cell, it knocks elec-trons loose and allows them to �ow as anelectrical current. Light of other frequen-cies can do the same trick with othermaterials. Researchers have known forseveral years, for example, that carbonnanotubes�tiny cylinders whose wallsare sheets of carbon�will release elec-trons when stimulated by infra-red light.

That discovery led to much experi-mentation, but little progress. The chiefdi�culty lies in the process used to makethe tubes. This actually produces a mix-ture of two di�erent sorts: ones that havemetal-like properties and ones that aresemiconducting. Solar cells need thesemiconducting variety. Metallic onespoison the process and must be removedbefore a cell can work properly.

Until now, researchers wishing to dothat have been forced to play a tediousgame of pick-up-sticks, selecting the semi-conducting nanotubes one by one andthen sticking them in place with glue. It ispossible to make a solar cell this way, but itis time-consuming and expensive. Worse,the chemical instability of the glue meanssuch cells tend to break down rapidly.

Dr Strano, however, has exploited anew manufacturing process based on apolymer gel that has an a�nity for semi-conducting nanotubes, but not metallicones. He is thus able to extract large num-bers of semiconducting tubes from amixture. That done, he deposits them in a100 nanometre-thick layer on top of apiece of glass, to which they stick withoutthe need for glue. The whole thing is thentopped with a layer of buckminsterfulle-rene, a form of carbon in which the atomsare arranged in tiny, cage-like spheres. This

layer acts as an electrode, so that the solarpanel can be connected to a circuit.

The result is not exactly e�cient. Ittransforms only around 0.1% of the infra-red light thrown at it into electricity (com-pared with 20% for an ordinary solar cell).But Dr Strano and his colleagues are none-theless jubilant. After all, 0.1% is a big stepup from nothing at all, and most existingsolar technologies began with similarlypoor e�ciencies that were improvedgradually over the course of time.

Moreover, the new technology has onebig bene�t. Though the carbon nanotubesabsorb infra-red light, they are almosttotally transparent to the visible variety.This means that, if and when they becomecommercially viable, they can be overlaidon traditional silicon cells to produce adevice that converts a larger fraction of theincident sunlight into electricity. 7

Catching a fewmore rays

Energy technology: A new type ofsolar panel can turn infra-red light,not just the visible sort, intoelectricity. But not very well yet

KEEPING drugs, and particularlyvaccines, potent in tropical climes is a

challenge. Heat tends to damage them.Such medicines have therefore to bemoved from one refrigerator to another,along what is referred to as a cold chain,until they arrive at the clinics where theyare to be administered. Fridges, however,are expensive. They also require electric-ity, which is not always available�or isavailable only unreliably�in the poorerparts of the world. As a consequence,breaks in cold chains are estimated by theWorld Health Organisation to destroyalmost half of the vaccines producedaround the world.

Some vaccines can be freeze-dried,which helps. But even when treated in thisway, their lifetime out of the fridge islimited. Ways of keeping drugs and vac-cines stable at tropical temperatureswould therefore be welcome. And DavidKaplan of Tufts University, in Massachu-setts, thinks he has found one. Put simply,he and his colleagues have worked outhow to pack medicines into tiny silkpouches, in a manner that makes themalmost indi�erent to heat.

Dr Kaplan and his team describe theirtechnique in a recent issue of Proceedings

of the National Academy of Sciences. Theystart with silkworm cocoons�the rawmaterial for almost all silk production.They boil the cocoons in a solution ofsodium carbonate to separate a proteincalled �broin, which is the one they want,from another, called sericin, which theydo not. They treat the �broin with salt,then mix it with the substance to be pre-served and spread the result out as �lms,before freeze-drying it. The resulting �lmsconsist of a �broin matrix �lled with tinypockets a few hundred nanometres (bil-lionths of a metre) across. These pocketscontain the medicine.

Packaging delicate medicines in thisway does, indeed, help preserve them. Itimmobilises the molecules, preventingthem from unfolding and thus losing theirpotency. It also minimises residual mois-ture even better than normal freeze-dry-ing. Dr Kaplan and his team demonstratedthe e�ectiveness of their new techniqueby trying it out on the MMR (measles,mumps and rubella) vaccine.

Prolonged storage at just 25°C willcause even the freeze-dried version ofMMR to break down. After six months itretains only 60-75% of its potency. If keptfor that length of time at 45°C (extreme,but not unknown in the tropics) it is practi-cally worthless. When stored using DrKaplan’s silk sheets, however, it was stillabout 85% potent after six months, regard-less of temperature.

When the researchers tried the sametrick with tetracycline, a commonly pre-scribed antibiotic, they got similar results.Tetracycline stored at body temperaturelost 80% of its potency after four weeks inordinary solution, but lost none whenstored in silk �lms. The new techniquealso worked with penicillin. Moreover,�broin is harmless to people�silk is, afterall, often used in sutures�so there is littlerisk of adverse side-e�ects. It probablydoes not matter if some silk gets into avaccine when it is dissolved in water priorto inoculation.

That said, the vaccines and antibioticsstored in this new way have yet to betested on people. That is the next step. Butif they work, this new trick will help savelives being needlessly lost in some of thepoorest parts of the world. 7

No sow’s ear

Medical technology: Packingvaccines and other medicines intotiny silk purses could help themretain their potency in hot countries

IN 1967 Stanley Milgram, an Americansocial scientist, conducted an experi-

ment in which he sent dozens of packagesto random people in Omaha, Nebraska.He asked them to pass them on to ac-quaintances who would, in turn, passthem on to get the packages closer to theirintended �nal recipients. His famousresult was that there were, on average, sixdegrees of separation between any twopeople. In 2011Facebook analysed the721m users of its social-networking siteand found that an average of 4.7 hopscould link any two of them viamutual friends. A small world isnow, it seems, even smaller.

Can this be used to solve real-world problems, by taking ad-vantage of the talents and connec-tions of one’s friends, and theirfriends? That is the aim of a new �eldknown as social mobilisation, whichtreats the population as a distributedknowledge resource which can betapped using modern technology. Itcould potentially be used to helplocate missing children, �nd astolen car or track down a suspect.Social-mobilisation researchershave been examining its potentialthrough some unusual, Milgram-like experiments.

One of the �rst examples was theRed Balloon Challenge, staged in2009 by DARPA, the research arm ofthe American Department of De-fence. Its aim was to determinehow quickly and e�cientlyinformation could be gatheredusing social media. The chal-lenge was simple: competitorsraced to locate ten red weatherballoons that had been teth-ered at random locationsacross the United States inreturn for a $40,000 prize. Insome ways this was similarto the way in which Usha-hidi, a non-pro�t website,gathers information insituations such as the earth-quake in Haiti and the terro-rist bombings in Mumbai. Thedi�erence, however, was that theRed Balloon Challenge was not acrisis, so participants had to �nd

another way to motivate others to reportsightings of the balloons.

The winning team, led by ManuelCebrian and Sandy Pentland of the Mas-sachusetts Institute of Technology (MIT),found all the balloons in just nine hours,using a clever incentive-based strategy toencourage participation. The �rst personto send the correct co-ordinates of a bal-loon received $2,000, but whoever recruit-ed that person received $1,000, and therecruiter’s recruiter received $500, and soon. This scheme proved to be highly opti-mised for the task, says Iyad Rahwan, wholater joined the MIT team.

In March this year DARPA staged anew contest, the Tag Challenge. This timethe goal was to locate and photograph �vepeople, each wearing unique T-shirts, in�ve named cities across two continents.All �ve had to be identi�ed within 12hours from nothing more than a mugshot.Compared with the Red Balloon Chal-lenge this was much more di�cult, says Dr

Rahwan, who is now at the MasdarInstitute in the United Arab Emir-

ates. �It involves people moving,moving in crowds and the targetsare much harder to spot, especial-ly in a big city.�

In the event none of the teamsmanaged to �nd all �ve targets. But

Dr Rahwan’s team, with membersfrom MIT, the universities of Edin-burgh and Southampton, and theUniversity of California, San Diego,did manage to �nd three�in New

York, Washington, DC and Brati-slava. With a prize fund of $5,000the stakes were lower, whichmeant a more targeted approach

was needed, says Dr Rahwan. So histeam built a website and a mobile

app to make it easier for people toreport sightings and recruit people.Each �nder was o�ered $500, and

whoever recruited the �nder $100.But limiting the reward in this waymeant that people who did notknow anyone in one of the targetcities had no incentive to recruit

someone who did. And despiteinvesting some of the potential prize

money to promote the team onFacebook and Twitter, Dr Rahwanand his colleagues found that most

participants used good old-fashioned e-mail.

It still counts as social mo-bilisation, says Nick Jennings,one of the team members atthe University of Southamp-ton, because there was stillperson-to-person referral and

recruitment. With the RedBalloon Challenge, the teamrecruited more than 5,000 peo-

ple, with some referral chainscontaining as many as 16 peo-

ple. In the Tag Challenge only a few hun-dred people were recruited, many of themdirectly by the team. Nevertheless, someparticipants found out about the chal-lenge via friends and colleagues.

Eventually, says Dr Jennings, smart-phones might have a �social mobilisation�search app that can query people all overthe world, who then steer the query to-wards the people with the right infor-mation. Perhaps some kind of socialcurrency could be used as a motivator. Inthe meantime, social mobilisation seemsto work best when it is done in a goodcause, or o�ers a �nancial incentive. 7

Six degrees ofmobilisation

Technology and society: To whatextent can social networking make iteasier to �nd people and solvereal-world problems?

The Economist Technology Quarterly September 1st 2012 Monitor 5

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CARBON monoxide gets a bad rap. Thegas, produced by incomplete combus-

tion of hydrocarbons, causes hundreds ofdeaths every year by poisoning and sendsmany thousands to hospital. Most of theseare the result of leaking cooking and heat-ing equipment, but the colourless, odour-less and tasteless substance, known tochemists as CO, has also aided many asuicide. Most horri�cally, Nazis used it ingas chambers.

But there is more to the �silent killer�,as CO is sometimes called. It is producedby many cells in the human body, whereits molecules play a crucial role in activat-ing enzymes involved in controlling thedilation of blood vessels, and thus blood�ow. Mice in which the gene for producingthe compound has been knocked outdevelop faulty organs and die young.

Exploiting this insight, researchershave successfully used CO to treat a num-ber of ailments in lab animals. Theseinclude pulmonary hypertension, anotherwise incurable disease in whichthickened arteries obstruct the �ow ofblood, leading to heart failure. The gas canalso keep in�ammation in check, in partic-ular after organ transplants.

The reason human patients have so farbeen unable to bene�t from any of this isCO’s gaseous nature, which makes itdi�cult to deliver in the right amounts tothe parts of the body that need it. Theproblem is exacerbated by CO’s narrow�therapeutic index�; pump too little in andit won’t work, but overshoot and it causesharm by binding irreversibly to haemoglo-bin, making less of that substance avail-able to carry oxygen around the body.

A silent healer

Medical technology: Researchershave developed novel ways to tap thepharmacological potential of aninfamous and deadly gas

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�IF THOMAS CRAPPER were aroundtoday, he would �nd our toilets quite

familiar,� says Bill Gates, referring to theVictorian manufacturer of sanitary warewhose name has become attached to oneof the body’s most fundamental func-tions. �They haven’t seen many advancesapart from handles and paper toilet-rolls.�In fact, with the exception of S-traps tocontain odours, �ush toilets have changedlittle since Sir John Harington installedone in Richmond Palace for Queen Eliza-beth I in the late 1590s.

Mr Gates considers it time for a change.On August 14th his charity, the Bill & Me-linda Gates Foundation, announced thegold-, silver- and bronze-medal winners inits Reinventing The Toilet Challenge,which aims to bring safe, a�ordable and�sustainable� loos to the 40% of the

world’s population who lack access tobasic sanitation. This could help preventmany of the 1.5m childhood deaths fromdiarrhoea that now occur each year.

The challenge is nothing if not ambi-tious. It seeks a toilet that costs less than�ve cents per user per day to operate, thatrequires neither a supply of clean waternor sewerage infrastructure to take thewaste away, and that will generate energyand recover salts, water and other nutri-ents. Even though the challenge is littlemore than a year old, the award winnersare on track to achieve all these goals.

In third place is a toilet designed byresearchers at the University of Toronto. Ittreats urine and faeces separately, using amaterial freely available in many of theworld’s poorest regions: sand. Urine is�ltered through sand, and the resulting�uid is sterilised with ultraviolet light.Faeces are dried slowly within the toiletbefore being fed into a smouldering sand-�lled reactor. The system can sanitise thewaste of ten people in two hours, leavingonly sand and fresh(ish) water behind.

The runner-up comes from Loughbor-ough University in Britain. A tank feedsmixed urine and faeces through a rig thatheats it to 200°C under high pressure,killing pathogens. Returning the super-heated mixture suddenly to atmosphericpressure causes it to separate into its liquidand gaseous components. The gas is usedto heat the feed tank. The liquid is fed intoa digester that produces enough methaneto power the system�and some to spare.

The winning toilet is smarter still. It hasbeen developed by Michael Ho�man ofthe California Institute of Technology, andhas earned him the $100,000 �rst prize.His toilet uses solar panels to power anelectrochemical system that turns wasteinto useful things. One is a compoundwhich oxidises the salts in urine to gener-

ate chlorine. This creates a mildly disin-fecting solution that can be used to �ushthe toilet. The second is hydrogen, whichis suitable for cooking or for powering afuel cell to produce electricity. The residuefrom the process can be used as fertiliser.

The Gates Foundation will now pay forprototypes to be tested in the �eld, prob-ably of all three winners and possibly ofsome other ideas. Mr Gates hopes that thefoundation’s reinvented toilets will startbeing deployed more widely in as little astwo years. They will thus be able to helpachieve what is the most o�-track of theUnited Nations’ Millennium Develop-ment Goals: to halve by 2015 the propor-tion of people without sustainable accessto basic sanitation. As the chairman of theUN Secretary-General’s Advisory Boardon Water and Sanitation, the Prince ofOrange, observes, �politicians and leadersworldwide don’t like to be associated withtoilets, even state-of-the-art toilets. Thissanitation stigma distorts internationaland national development agendas.�

Dr Ho�man agrees that sanitation isinsu�ciently sexy. He says the technologybehind his solar-powered toilet had beensitting on the shelf since he demonstratedit to NASA, America’s space agency, in theearly 1990s, for use on the InternationalSpace Station. �It is hard to get a scienti�cgrant for treating faeces,� he says.

Even the Gates Foundation itself,which hands out around $3 billion eachyear, has devoted just $6.5m to its Rein-venting The Toilet Challenge. But that willchange as the project moves from concep-tion to delivery. The foundation plans tospend up to $80m a year on sanitation, aninvestment that the World Health Organi-sation estimates will produce a return of900% in the form of social and economicbene�ts from increased productivity andreduced health-care costs. 7

Flushed withpride

Technology and development: Eachyear 1.5m children die fromdiarrhoea. Better toilets couldreduce the death toll

Thomas Crapper would be amazed

Frederick Montgomery and DuncanBathe think they have come up with away to hit the sweet spot. Their Coke-can-sized gizmo, which they devised whileworking at Ikaria, an American drug �rmthat both have since left, contains a car-tridge of pressurised CO, a tube to deliverthe gas to the patient’s nose, and a fewbuttons to set the required dose. A sensorconnected to a nozzle at the end of thetube constantly measures the patient’sbreathing rate and adjusts the amount ofCO dispensed with each breath. Safetyfeatures, including automatic shutdown ifanything seems amiss, are meant to elim-inate the risk of CO overdose and ensurethat none leaks out, endangering others.

Scientists at another American phar-maceutical company, Sangart, meanwhile,have been encasing the gas�or, strictlyspeaking, CO-ferrying haemoglobin�in apolymer pouch. Kim Vandegri� and hercolleagues have been using polymerwrappers a mere nanometre (a billionthof a metre) across. These can be designedto break open only where their payload isneeded. Early trials have shown promisein treating sickle-cell anaemia, a diseasecaused by a faulty haemoglobin gene.

Unlike most drugs, CO is not brokendown by the body. Instead, once its job isdone, it is transported to the lungs andexhaled. As a result, it produces no side-e�ects. Given the right dose, then, it canheal silently, too. 7

The Economist Technology Quarterly September 1st 2012 Di�erence engine 7

TRACKING down early web pages canbe a problem. The Economist’s �rst web-

site, for instance, was built by the paper’sCalifornia correspondent and went live inMarch 1994. Eighteen months later, it wasrecon�gured and brought in-house. All re-cords of the original website were subse-quently lost. So much for the idea that theinternet never forgets. It does.

There are not even any screen shots ofthe world’s �rst web page�the one that ac-tually launched the World Wide Web inAugust 1991. Type in its address and youwill see a modern site that provides detailsof Tim Berners-Lee’s seminal achieve-ments at CERN, the European Organisa-tion for Nuclear Research where he de-vised the �rst web browser and server.

Amid the explosive growth of internetservices such as e-mail, music downloadsand video streaming, along with thegrowth of the web itself, little thought hasbeen given to recording information forposterity. The rapid turnover of content onthe web has made total loss the norm.�Civilisation is developing severe amnesiaas a result,� says Stewart Brand of The LongNow Foundation. Danny Hillis, a pioneerof parallel computing and machine intelli-gence, fears the world has become stuck ina digital dark age, with few cultural arte-facts from its digital past to point the way.

Lacking cultural artefacts, society hasno mechanism to learn from previous mis-takes. It is not hard to see where that canlead. The Library of Alexandria�built dur-ing the 3rd century BC to house the accu-mulated knowledge of centuries�reputed-ly had a copy (often the only copy) of everybook in the world at the time. It burned tothe ground sometime between Julius Cae-sar’s conquest of Egypt in 48BC and theMuslim invasion in 640AD.

It remains unclear how, when or whythe �re started. But it destroyed many ofthe works of Aristotle, Aeschylus, Euripi-des, Sophocles and countless other an-cient astronomers, mathematicians, poets,playwrights and philosophers. All that re-mains today stems from a small fraction ofthe Alexandrian archives that had beenbacked up in a daughter temple called theSerapeum. Some historians believe theloss of the Alexandrian library, along withthe dissolution of its huge community ofscribes and scholars, created the condi-tions for the Dark Ages that descended

across Europe as the Roman empire crum-bled from within. A millennium of miseryensued, with ignorance and poverty therule until the Renaissance dawned.

No one is saying that today’s digitaldark age portends any such disaster. Nev-ertheless, there could be serious rami�ca-tions for education, scholarship, govern-ment and even national security. All arelegitimate concerns for the future.

It is not really surprising that attemptsto dig up The Economist’s early web pageshave come to naught. The original siteceased serving pages several years beforetoday’s search engines came into being.Those around at the time (eg, Aliweb,JumpStation and WebCrawler) have longbeen pensioned o�, or subsumed into oth-er services. Even the Wayback Machine�a

search engine that allows users to call upold web pages which have vanished fromthe scene�came up empty handed.

The Wayback Machine’s inventor,Brewster Kahle, is an internet entrepre-neur, philanthropist and computer whizzwho helped design Mr Hillis’s ground-breaking Connection Machine in the1980s. In 1996 he founded a non-pro�t orga-nisation, the Internet Archive, to create afree internet library capable of storing acopy of every web page of every websiteever to go online. The Wayback Machineallows users to view the library’s archivedweb pages as they appeared when pub-lished. Today the Internet Archive also in-

cludes texts, audio, moving images andsoftware. At the last count, its collectioncontained more than 150 billion items.

An interesting spin-o� from the Inter-net Archive is the Open Library, whichaims to provide a web page for every bookin existence. The Open Library is not to beconfused with Project Gutenberg, foundedby the late Michael Hart, the inventor ofthe electronic book back in 1971. Project Gu-tenberg o�ers some 40,000 e-books thatcan be downloaded free in any of the pop-ular e-reader formats.

Open sesameOpen Library, by contrast, is essentially aneditable catalogue. The organisationworks with various libraries around theworld to catalogue their book collectionsand scan in various texts. So far it hasamassed details of over 20m titles andscanned in the contents of some 1.7mbooks that are in the public domain, andtherefore free to download. If a book is stillin copyright, it can be checked out as a digi-tal loan for a couple of weeks�rather like abook from a bricks-and-mortar library.

But why is Mr Kahle doing all this whenGoogle, Amazon, Apple and others areputting civilisation’s creative outpouringsonline as fast as their editing, scanning andrecording machines can cope? The obviousanswer is because these commercial enti-ties charge for access to some information,whereas non-pro�t archives are generallyfree. Money aside, there are other reasonsfor encouraging open-source archives. Forone, commercial out�ts can be picky aboutgranting search engines, other than theirown, access to content they have archived.And even with material old enough to bein the public domain, users of proprietaryarchives can still be denied the right tocopy or distribute it.

As the Internet Archive notes, withoutlibraries, people would �nd it hard to exer-cise their �right to remember�. As moreand more public information moves fromprinted to digital form, it is vital that virtuallibraries of all kinds archive as much of itas they can in the interests of future refer-ence and accountability. For its part The

Economist has made available digitalcopies of every issue going back to the dayit was launched in 1843. But it is not alone inlacking copies of the web pages it pro-duced just a few years ago. 7

Lost in cyberspace

Technology and society: Amid the explosive growth of digital content on the internet, little thought has been given topreserving things for posterity. Will historians of the future wish that web pages had been preserved more carefully?

8 Energy weapons The Economist Technology Quarterly September 1st 2012

FOR a weapons test, it was a strangelyquiet a�air. A motorboat, of just the sort

that might be used by pirates or suicide-bombers trying to attack a warship,bobbed on the Paci�c swell. A �ash of red�ared up on one of its outboard motors.Just a few seconds later smoke was curlingskyward and the motor started burningbrightly. The American Navy’s MaritimeLaser Demonstration Program is a relative-ly puny weapon, with a total power outputof just over 100 kilowatts (kW). That is a farcry from the photon torpedoes and phas-ers of science-�ction lore, and nothing likeenough power to shoot down a fast-mov-ing aircraft or missile. But the prototypeweapon’s successful test in April 2011was amilestone towards the employment of la-sers, microwaves and similar �direct-ener-gy weapons� on warships in the comingyears. It was the �rst laser weapon to be in-tegrated with a warship’s radar and othersystems and used at sea to destroy a target.

The notion of using energy as a weap-on of war dates back at least as far as theancient Greeks. Archimedes purportedlyused a �heat ray�, in which the sun’s rayswere focused by mirrors, to set �re to ene-my ships during the siege of Syracuse inthe 3rd century BC. More recently, in themid-1930s British scientists looked into

building a death-ray that used radio wavesto destroy enemy aircraft. They concludedthat radio waves could best be used to de-termine the position of enemy aircraft in-stead, leading to the invention of radar.

In the late 1970s and early 1980s the ideawas revived when American strategists be-gan thinking in earnest about the technol-ogies they would need to shoot down nuc-lear-armed ballistic missiles. Among themore fanciful ideas taken up by RonaldReagan’s Strategic Defence Initiative (morecommonly known as Star Wars) was theX-ray laser, which aimed to harness the en-ergy of an atomic explosion to generatepowerful laser beams. The hassle of hav-ing to explode a nuclear bomb every time abeam was needed meant the idea neverwent anywhere, though it did spur re-search into high-powered chemical lasersand the sophisticated optics needed to aimand control them.

The main appeal of using an energybeam to shoot things is that it travels at thespeed of light, which means, in practice,that it will hit whatever it is aimed at. Try-ing to shoot down an incoming missile orwarhead with a physical projectile, by con-trast, is much more di�cult. The guidancechallenges of trying to �hit a bullet with abullet� are enormous and are only gradu-

ally being solved using complex radarsand missiles equipped with expensivesensors. A second attraction of lasers andother energy weapons is that in most casesthey cannot run out of ammunition, andcan keep �ring for as long as they areplugged into a power source. The initialcosts may be quite high, but each shot maythen cost only a few dollars, comparedwith a price-tag of $3m or more for the lat-est missiles used to shoot down aircraft orother missiles.

Yet until very recently, despite the bil-lions of dollars invested in them, militarylasers have had a less than glowing record.The most famous (and expensive) experi-ment was America’s Airborne Laser TestBed. This programme, which cost the Pen-tagon about $5 billion over more than 15years, was an e�ort to cram a huge lasergun into a Boeing 747. It was intended toshoot down ballistic missiles in their�boost phase�, after their launch but be-fore they had picked up enough speed toleave the atmosphere. The logic was thatthis is a particularly vulnerable time for amissile, since it is moving relatively slowlyand because even minor damage to an ac-celerating rocket could prove fatal giventhe enormous stresses it is subjected to.

The airborne laser showed some pro-mise in tests, but the programme was igno-miniously zapped in 2011 by the Pentagon,which couldn’t quite work out how itwould be able to keep a big, slow-movingjumbo jet airborne around the clock, deep

Zap, crackle and pop

Military technology: Energy weapons are �nally moving from the laboratoryto the real world. But they are hardly the super-weapons of science �ction

1

The Economist Technology Quarterly September 1st 2012 Energy weapons 9

2 within enemy territory, while waiting for amissile to blast o� nearby.

Another laser that came close to beingpractical enough to use was the TacticalHigh Energy Laser, also known as the Nau-tilus laser (pictured on previous page),which was designed to shoot down in-coming artillery rounds. It was successful-ly tested in Israel, where it intercepted in-coming rockets and shells, but Israel andAmerica decided to pull the plug on it. Onereason that it and the airborne laser wereshot down was that military planners fellout of love with chemical lasers. These arevery large and not especially portable la-sers that are powered by a chemical reac-tion. As well as being bulky, they requirelarge amounts of toxic and perishablechemicals, which can run out, limiting thenumber of shots that the laser can �re.

Switch o� the TV, we’re �ring the laserFor the moment, the idea of shootingdown big nuclear-tipped missiles with la-sers has been put on hold, and proponentsof laser weapons are aiming instead atmore �ammable targets. Much of the workin this �eld is now being done by theAmerican navy, mainly because shipsmake excellent platforms for laser weap-ons: there is usually plenty of space andoodles of power available, along with lotsof water for cooling the laser down. Manyof the latest ships are also being built withelectric propulsion systems: their enginesturn huge electricity generators, the powerfrom which can be used both to propel theship and to power its weapons.

The big trend now is to try to scale upthree other sorts of laser that are far morecompact than chemical lasers and can �reaway merrily as long as they have powerand don’t get too hot. The �rst sort is the �-bre laser, in which the beam is generatedwithin an optical �bre. Because this is al-ready used in industry for welding and cut-ting, prices are falling, power output is in-creasing and reliability has been steadilyimproving. Industrial lasers can be turnedinto weapons pretty easily, simply bystrapping them to a weapons mount.

But they are not very powerful. The Tac-tical Laser System being developed for theAmerican navy by BAE Systems, a British�rm, has an output of just 10kW, enough torun a few household kettles. Even so, itmight be useful for frightening o� (or burn-ing holes in) small boats that look threaten-ing but wouldn’t warrant a hail ofmachinegun �re. A slightly bigger versionputs out about 33kW of power and �tsneatly on existing turrets that house the ro-

tary cannons used to shoot down incom-ing anti-ship missiles. It could blind opticalor heat-seeking sensors on enemy mis-siles, or puncture small boats.

Plans are afoot to scale military �bre la-sers up to about 100kW, which would en-able them to shoot down small unmannedaircraft. The technology is relatively ma-ture: a study by the Congressional Re-search Service (CRS), an American govern-ment-research body, reckons it would costaround $150m to develop a prototype, andthat such lasers could be in service by 2017.

The second technology being workedon is the slab laser. This is similar to a �brelaser, but uses a slab of optical material asthe gain medium and produces a morepowerful beam. The CRS estimates that ex-isting technology should be able to pro-duce 300kW beams, and that it could bescaled up to produce beams of about600kW. That would be enough to shootdown high-speed cruise missiles, for ex-ample, but only sideways on.

It would be less useful for shootingdown targets �ying directly at the laser be-cause of �thermal blooming�: when ahigh-powered laser �res in the same direc-tion for a few seconds it warms the air,which a�ects the power of the beam. TheCenter for Strategic and Budgetary Assess-ments, a think-tank based in Washington,DC, argues that various sorts of solid-statelasers could be in service on Americanships by 2018. It thinks that they could alsobe used to counter cruise missiles �ying di-rectly at a ship, using relay mirrors mount-ed on nearby unmanned aircraft.

To be really suitable for shooting downballistic missiles, however, a laser with apower level of more than a megawattwould be needed. That would mean using

a third technology, called a free-electron la-ser. Such lasers are being developed al-most exclusively by the American navy be-cause they are too big to �t on planes ortrucks. They work by shooting a stream ofelectrons at high speed through an undu-lating magnetic �eld, causing the electronsto emit radiation that coheres to form thebeam. As well as being powerful, free-elec-tron lasers have the advantage that theycan be tuned to a precise frequency, allow-ing the beam to be adjusted for di�erent at-mospheric conditions. For the moment,however, these lasers are bulky and ine�-cient, and are probably two decades awayfrom being practical weapons.

Although lasers have many advan-tages, in short, they also su�er from quitesevere limitations. The main one is theirrelatively low power output. So much en-ergy is needed to burn through the armourof a tank, for instance, that it is easier sim-ply to �re a rocket at it. Even people do notmake particularly good targets for lasers:human bodies can absorb a lot of energybefore heating up substantially. (Eyesmake a better target, but international con-ventions ban lasers designed to blind.)

A further limitation is that laser lightcan be absorbed or scattered by pollution,fog or smoke. Missiles or other targets canalso be protected by coating them withmirrors or wrapping them with insulation.In addition, laser beams travel in a straightline, which means they are less useful thanconventional artillery when shooting atsomething on the other side of a hill. Itseems likely that laser weapons will havebeen deployed on ships by the end of thedecade. They will have their uses, but theyremain rather less fearsome than their sci-ence-�ction reputation might suggest. 7

Packing some heat: BAE’s Tactical Laser System

�So much energy is needed to burn through a tank’sarmour that it is easier simply to �re a rocket at it.�

WHICH plastic gadget, �tting neatly inone hand, can most quickly improve

the lives of the world’s poorest people? Forthe past decade the answer has been clear:the mobile phone. But over the next de-cade it will be the solar-powered lamp,made up of a few light-emitting diodes(LEDs), a solar panel and a small recharge-able battery, encased in a durable plasticshell. Just as the spread of mobile phonesin poor countries has transformed livesand boosted economic activity, solar light-ing is poised to improve incomes, educa-tional attainment and health across the de-veloping world.

As previously happened with mobilephones, solar lighting is falling in price, im-proving in quality and bene�ting fromnew business models that make it more ac-cessible and a�ordable to those at the bot-tom of the pyramid. And its spread is sus-tainable because it is being driven bymarket forces, not charity.

Phones spread quickly because theyprovided a substitute for travel and poorinfrastructure, helped traders �nd betterprices and boosted entrepreneurship. For a�sherman or a farmer, buying a mobilephone made sense because it paid for itselfwithin a few months. The economic casefor solar lighting is even clearer: buying alamp that charges in the sun during theday, and then produces light at night, caneliminate spending on the kerosene thatfuels conventional lamps. Of the 1.4 billionpeople without access to grid electricity,most live in equatorial latitudes where the

sun sets quickly and there is only a briefperiod of twilight. But solar lamps workanywhere the sun shines, even in placesthat are o� the grid, or where grid power isexpensive or unreliable.

The potential savings are huge. Accord-ing to a recent study by the InternationalFinance Corporation, an arm of the WorldBank, $10 billion a year is spent on kero-sene in sub-Saharan Africa alone to illumi-nate homes, workplaces and communityareas. Globally, the �gure has been put at$36 billion. Flexiway, an Australian-Argen-tine maker of solar lamps, found in itstrials in Tanzania that households oftenspent more than 10% of their income onkerosene, and other studies have put the�gure as high as 25%. And kerosene doesnot merely eat up household income thatcould be spent on other things. It is alsodangerous. Kerosene lanterns, a century-old technology, are �re hazards. The wickssmoke, the glass cracks, and the light maybe too weak to read by. The World HealthOrganisation says the �ne particles in kero-sene fumes cause chronic pulmonary dis-ease. Burning kerosene also produces cli-mate-changing carbon-dioxide emissions.

Take a look at some of the solar lampsnow available in Africa, Asia and Latin

America, and their advantages are imme-diately apparent. Even the most basic solarlamps outperform kerosene lanterns. Atypical device takes eight to ten hours tocharge, and then provides four or �vehours of clear, white light from high-e�-ciency white LEDs. The number of timessolar lamps can be charged before their in-ternal batteries wear out has improvedenormously in recent years, along withtheir ability to cope with dust, water andbeing dropped. The starting price of $10 orso is still too high for the poorest customersto pay, at least up front. But as with mobilephones, prices continue to fall and novelbusiness models are starting to providenew ways to spread the cost.

Let there be light�The technology end of the solar businessis there�now we have to think of the busi-ness model,� says Nick Hughes, co-foun-der of M-KOPA, a start-up based in Kenya.He previously helped develop M-PESA,Kenya’s world-leading mobile-moneytransfer scheme, which is used by nearly70% of the adult population and hasspawned imitators in many other coun-tries. Mr Hughes now wants to apply thesame thinking to lighting.

The M-KOPA system consists of a base-station with a solar panel, three lamps anda charging kit for phones�an entire electri-cal system for a small house that wouldnormally cost around $200. Customers inKenya pay $30 up front and then pay o�the balance in small instalments using

Lighting the way

Energy technology: Cheaper andbetter solar-powered electric lightspromise to do away withkerosene-fuelled lanterns

10 Solar lighting The Economist Technology Quarterly September 1st 2012

1

their mobile phones. As long as they keepmaking payments, the system providesfree light and power, and eventually theyown it outright. Using mobile money as a�exible payment mechanism means thatrelatives can chip in remotely and allowsfarmers to vary the size of payments de-pending on their cash�ow. It also providesa mechanism for the government to pro-vide subsidies for households with in-fants, or children studying for exams. Inaddition, the base-station provides a pay-ment record which could be used by banksas a credit history when o�ering loans ormortgages. The �rst commercial unitswent on sale in June.

Eight19, a start-up spun out of Cam-bridge University, has a similar model inwhich small payments, like those used tobuy kerosene, allow the purchase of a so-lar-lighting system to be spread out. Usersof its IndiGo system pay around $10 upfront. They then buy scratch cards for as lit-tle as $1each, and send the number on eachcard by text message to a central server thatresponds with an access code that istapped into the IndiGo unit and provides acertain number of hours of lighting. Again,each payment goes toward buying the sys-tem outright, and a typical family will havepaid for it after 18 months of use. Evenwhile paying o� the loan with scratchcards, users pay half as much for each hourof lighting as they did with kerosene. Withboth M-KOPA and Eight19 models, thelights go out if the payments stop, provid-ing an incentive to keep paying.

Another novel approach is that takenby SociaLite, a scheme developed by WaPolytechnic in Ghana and the Cooper Un-ion in New York. It involves a centralised,village-level system with a large solar pan-el that charges a car battery. This is used, inturn, to charge smaller batteries in the lan-terns, which are built using local materials.A family pays $4-5 for the lamp (in e�ect,for membership of the scheme) and then$1-2 a month for recharging. These chargesenabled the villagers to pay for the entiresystem within 18 months or so. Everythingis designed to be maintained and repairedby locals: if a lamp fails it is replaced withanother one while being repaired. This im-proves reliability, and centralising the solarcharging reduces the cost of each lamp.

Lighting Africa, a World Bank projectwhose aim is to �catalyse markets for mod-ern lighting�, has certi�ed a list of solarlamps that meet minimum standards forreliability and recommended targets forbrightness and run time. One of the suppli-ers on its list is an American company,

d.light, which specialises in durable, utili-tarian designs. Its workhorse is the S10 lan-tern. It is intended to deliver ambient lightrather than directed light for tasks, and con-tains a nickel-metal-hydride battery, ratherthan a cheaper nickel-cadmium cell. In aninformal test of solar lights carried out byThe Economist in Africa, users grumbledabout the soapy quality of light and lan-tern-style design. But the company haswon plaudits for its other models: its larg-est lamp, the S250, was included by theBritish Museum in its �History of theWorld in 100 Objects� exhibition as the100th object. The smaller S1 model, whichcosts $8, is intended for use as a desk lamp(see photo on previous page).

Tried and testedThe N200 lantern made by another Ameri-can �rm, Nokero (for �no kerosene�), has adesign inspired by a light bulb, and costsabout $15. It worked well for cooking,cleaning and sitting around a table, butwas deemed less suitable for studying. TheSolar Muscle, a solar lamp made by Flexi-way, can be used as a desk light. Its com-pact, square design, with a so-lar panel on one side andLEDs on the other, alsoallows several lampsto be snapped togeth-er to make a largerpanel. The squaredesign arose afteran earlier, circularversion was mis-taken for a land-mine, says JamesFraser of Flexiway.The �rm can pack2,750 of its $10 lamps ina cubic metre�a plus incountries where transport isexpensive. They are being distri-buted by NGOs in Papua New Guinea andseveral African countries.

The best solar lamp among those testedwas the Sun King, produced by an Indiancompany, Greenlight Planet. It was pur-chased o� the shelf from an African super-market for $24. The Sun King’s almost daz-zling light was appreciated by users, as wasits seemingly unbreakable design. Theawkward-looking wire stand worked well.The lamp’s only drawback was that its so-lar panel is separate, rather than beingbuilt into the lamp.

As with mobile phones a decade ago,there is still plenty of scope for improve-ment and innovation. On the technicalfront, the biggest remaining problem is the

batteries. Nickel-metal-hydride batteriesare more expensive and less polluting thannickel-cadmium cells, and have a longerlife. Lithium-ion batteries, the sort found inlaptops and mobile phones, are better still,but are too expensive. Most solar lamps al-low the battery to be replaced once itwears out, and some (such as Flexiway’s)use standard-sized rechargeable batteriesto make replacement as simple as possible.But this creates a new pollution problem:there are no facilities to recycle the old bat-teries. Flexiway suggests that entrepre-neurs selling rechargeable batteries couldo�er a discount when old batteries weretraded in and gather them up for central-ised recycling, but it is unclear whether thismodel would work.

The importance of design should notbe overlooked. Just as mobile phones havebecome status symbols, the same couldhappen with personal solar lamps. Thatwill mean placing more emphasis on styl-ing and appealing to younger consumers,for whom a device capable of doubling asa torch and desk light would be particular-ly useful. A lamp (pictured) made by a

Danish designer, Frederik Otte-sen, and an Icelandic artist,

Olafur Eliasson, winsplaudits in this regard.

Called Little Sun,it looks like a plasticsun�ower. The de-sign helps keep thebattery cool whilecharging and pro-tects the lamp if it isdropped. Because

the average age ofthe projected user is

15, says Mr Ottesen, �theaim was to make it friend-

ly, like a Pokemon �gure.� Hehopes to sell 400,000 lamps, at

around $10 each, through local retailers inKenya, Ethiopia and Zimbabwe. Mr Elias-son, known for his large-scale light installa-tions such as the �Weather Project� at TateModern, says solar lamps �should not bedesigned with the language of the aid andrelief industry.�

Demand for cheap, e�cient lighting isonly going to grow. Even in the best-casescenarios, the number of people withoutelectricity will tick up to 1.5 billion by 2030,as population growth outstrips electri�ca-tion. The rate of innovation in deliverymodels, technology and design, in bothrich and poor countries, suggests a brightfuture for solar lamps�and a slow dim-ming of kerosene’s �ame. 7

�Solar lamps work anywhere the sun shines, even in places that are o� the grid.�

The Economist Technology Quarterly September 1st 2012 Solar lighting 11

2

IN AN average month 108,000 people arekilled in tra�c accidents around the

world, and the death toll is increasing. Oncurrent trends it will exceed 150,000 peo-ple a month by 2020, according to theWorld Health Organisation, as cars be-come more widespread in developingcountries, increasing the number of vehi-cles on the world’s roads from around 1bil-lion in 2010 to 2 billion. Many lives will bespared by out�tting more vehicles with air-bags, the biggest lifesavers in car technol-ogy since seat belts. But now a far greaterrevolution in road safety is within reach.Around 90% of accidents are caused by hu-man error. Design vehicles so that they candrive themselves, goes the theory, anddeath tolls will plummet.

Driverless cars would provide furtherbene�ts beyond safety. They could co-ordi-nate their routes and travel in close forma-tion, increasing the capacity of road net-works, reducing congestion and savingfuel. They would be able to drop someoneo� and then go and park themselves. Theymight even usher in an era of widespreadcar-sharing, with vehicles dispatched ondemand to people who need them, ratherthan spending most of the day sitting idle

by the side of the road. And they would, ofcourse, do away with the stress of driving,allowing their occupants to read, browsethe internet or take a nap. It may sound likescience �ction, but much of the technol-ogy needed to turn ordinary vehicles intoself-driving ones already exists. Indeed, al-most all carmakers are developing sensors,control systems and other equipment thatturns cars, in e�ect, into autonomous ro-bots. Prototypes are on the roads today.

Thilo Koslowski, an analyst at Gartner,a market-research �rm, predicts that suchvehicles will be on sale within eight years.Erik Coelingh, a senior engineer for �driversupport� systems at Volvo, a Swedish car-maker, reckons it will take at least ten.However long it takes, the transition willbe gradual. Before fully autonomous vehi-cles arrive, humans will remain behind thewheel, gradually handing o� more andmore of the job of driving to an autopilot.Owners of cars with advanced driver-as-sistance features have already embarkedon this transition.

Just around the cornerSince the late 1990s some cars have had theoption of �adaptive� cruise control thatuses a radar system to monitor the positionof the car in front, and accelerates or brakesautomatically. General Motors, America’sbiggest carmaker, is designing a �supercruise� option that steers automatically inslow tra�c, following lane markers andavoiding other vehicles, says Jeremy Salin-

ger of GM, who heads the team developingthe technology. Ford, America’s second-largest carmaker, is developing somethingsimilar called Tra�c Jam Assist. BMW

plans to launch a compact electric car, thei3, that can do this trick next year. It willcost less than �40,000 ($50,000), saysRalph Huber of BMW.

Autonomous driving in slow tra�c is alogical combination of adaptive cruise-control and the lane-keeping systems, al-ready available in some vehicles, which ei-ther warn the driver if the car starts to driftout of lane, or apply corrective steering tokeep it in lane. In addition, a growing num-ber of car models have the option of self-parking systems. The job of the driver is, inshort, slowly being chipped away. The in-dustry will build fully autonomous cars,says Mr Salinger.

The addition of autonomous controlneed not add much to the cost. An extra$3,000 or so should cover it, Mr Coelinghbelieves. And there is evidence that driversare prepared to pay for add-ons that im-prove safety as well as convenience. Volvoalready sells a popular driver-assistanceoption called City Safety for around$2,000, for example. It slams on the brakesif a distance-measuring laser or camera de-tects a vehicle or pedestrian in the car’spath. City Safety can prevent collisionscompletely at speeds of up to 30kph(18mph), and at higher speeds it softens theimpact. A similar braking system on Mer-cedes-Benz vehicles has reduced insuranceclaims for bodily injury by roughly a sixth,according to the Highway Loss Data Insti-tute, an American research group.

As adaptive cruise controls, self-park-ing options and automated-braking sys-tems gradually become more capable andwidespread, it is not a big leap to full au-tonomous control. Prototypes are startingto move o� test tracks and onto real roads.Last year BMW sent a robotic car at motor-way speeds from Munich, the German car-maker’s hometown, to Nuremberg, about170km to the north. (A professional driversat behind the wheel just in case.) Audi,part of the Volkswagen Group, caused astir two years ago when it sent a self-driv-ing TTS Coupe through 156 tight curvesalong nearly 20km of paved and dirt roadon Colorado’s Pikes Peak, with nobody be-hind the wheel. Modi�ed with help fromroboticists at Stanford University, the cartravelled about as fast as one driven by anaverage driver. Peter Oel, head of Volks-wagen’s Silicon Valley Electronics Re-search Lab, says his team even pro-grammed the car, named Shelley, to skid its

Look, no hands

Automotive technology: Driverlesscars promise to reduce roadaccidents, ease congestion andrevolutionise transport

12 Inside story The Economist Technology Quarterly September 1st 2012

1

The Economist Technology Quarterly September 1st 2012 Inside story 13

2

1

rear tyres on tight corners, a trick known as�drifting�. (The same car recently drove it-self at 190kph on a racetrack.)

Getting a car to drive along an openroad without crashing into other vehiclesis one thing. Getting it to handle a completejourney on its own�including navigatingjunctions and roundabouts, respondingappropriately at pedestrian crossings andavoiding obstacles on the road�is rathermore di�cult. To build such a machinecosts around $1m for the car, kit, software,and brainpower, says Jonathan Sprinkle,co-leader of an American-Australian teamthat entered a driverless vehicle in the2007 DARPA Urban Challenge, a robotic-car contest sponsored by the research armof the American Department of Defence.Because modern engines, drivetrains, andbrakes already receive their instructionsvia electronic signals, there is surprisinglylittle need for additional mechanical parts.

What is needed, however, is an array ofextra sensors to make cars more aware oftheir surroundings. Mapping nearby fea-tures, spotting road edges and lane mark-ings, reading signs and tra�c lights andidentifying pedestrians is done using acombination of cameras, radar and lidar(which works like radar, but with pulses oflight rather than radio waves). Ultrasonicdetectors provide more accurate mapping

of the surroundings at short range, for ex-ample when parking. Gyroscopes, acceler-ometers and altimeters provide more accu-rate positioning than is possible usingglobal-positioning system (GPS) satellitesalone. All this can cost $200,000 for an ex-perimental car, says Dr Sprinkle.

Google spent roughly that much �ttingout each of the dozen or so robotic vehiclesit has built by modifying American, Ger-man and Japanese cars. Eventually, fewerand cheaper sensors should do the trick,but Google and other researchers are stillworking out how to combine readingsfrom multiple sensors, and determiningwhich sensors work best in conditionssuch as night driving or heavy rain. So farthe internet giant’s �eet has collectivelyclocked up nearly 500,000km under au-tonomous control, on both test tracks andpublic roads, including San Francisco’sLombard Street, one of America’s steepestand most twisty roadways.

Teaching computers to driveOnce the sensors and activators are inplace, building a driverless car is essential-ly a software problem. Google’s approachinvolves driving a route manually, with allthe sensors switched on, to build a detailed3D map of features such as signs, guard-rails and overpasses, says Anthony Levan-

dowski, project leader for Google’s self-driving cars. Then, when the autonomous-driving mode is switched on (accompa-nied by a spaceship sound-e�ect), the soft-ware can predict hazards with reasonableaccuracy. A shaded bridge in a damp val-ley, for example, may be icy until noon ifthe night-time temperature drops below acertain point. Each time a car follows a par-ticular route, it collects more data. Google’ssoftware also ingests data on speed limitsand recorded accidents. Because the car’sroof-mounted sensors can see in all direc-tions, it arguably has greater situationalawareness than a human driver.

One area where humans are still clearlysuperior, however, is in judging an object’smaterial or weight. Unable to tell the di�er-ence between a chunk of mattress and ablock of steel on the carriageway, a self-driving vehicle might brake harder thanwould be wise, says Sebastian Thrun, aStanford University roboticist who led thedevelopment of Google’s driverless cars.Similarly, a carpet of leaves or snow mightlead a robotic car to miscalculate the posi-tion of the road’s edge.

But as driverless cars clock up moremiles, solutions are being worked out. Toevaluate the danger posed by an object onthe road, Google’s software takes into ac-count the behaviour of other vehicles. Ifother cars do not swerve or brake to avoidit, it is more likely to be a plastic bag than arock. �Fusing� data from various types ofsensors can also remove uncertainty. Tojudge distances, for example, radar or lidarsensors in the front bumpers can be sup-plemented by video cameras. Infra-redsensors can pick up the heat signature of ahuman obscured by fog.

It is even possible to make judgmentsabout the mental or physical state of otherdrivers. Software developed by Probayes,a �rm based near Grenoble, in France,identi�es and then steers clear of driverswho are angry, drowsy, tipsy or aggressive.Upset drivers tend to speed up and brakequickly. Sleepy drivers tend to drift o�course gradually and veer back sharply.Drunk drivers struggle to keep a straightline. The �rm sells its software to Toyota,Japan’s car giant. Google’s cars have evenbeen programmed to behave appropriate-ly at junctions such as four-way stops, edg-ing forward cautiously to signal their in-tentions and stopping quickly if anotherdriver moves out of turn.

So far Google’s vehicles have not beeninvolved in a single accident while undercomputer control; although a Google carcrashed into the back of another car in 2011,

Under the bonnetHow a self-driving car works

Source: The Economist

Radarsensor

Video cameras detect traffic lights,read road signs, keep track of theposition of other vehicles and lookout for pedestrians and obstacles on the road

Radar sensors monitor the position of othervehicles nearby. Such sensors are already usedin adaptive cruise-control systems

Lidar (light detection and ranging)sensors bounce pulses of light off thesurroundings. These are analysed toidentify lane markings and the edges of roads

Ultrasonic sensors maybe used to measure theposition of objects veryclose to the vehicle,such as curbs and othervehicles when parking

Signals from GPS (global positioning system)satellites are combined with readings fromtachometers, altimetersand gyroscopes to provide more accurate positioningthan is possible withGPS alone

The information from allof the sensors is analysedby a central computer thatmanipulates the steering,accelerator and brakes. Its software must understandthe rules of the road, bothformal and informal

14 Inside story The Economist Technology Quarterly September 1st 2012

2 it was being driven by a human at the time.The company says its cars have yet to mas-ter snow-covered roads, or reading tempo-rary signs and signals around roadworks.A telling sign of progress, however, is thatGoogle researchers have recently startedusing the cars solo, rather than in pairs.This lets individual researchers commuteto work in their autonomous cars.

The road aheadAutonomous vehicles for individuals maystill be a few years away, but they are al-ready being used in industry. Late last yearRio Tinto, an Anglo-Australian mininggiant, decided to increase its �eet of self-driving trucks, which haul iron ore, fromten to 150 vehicles within four years.Manufactured by a subsidiary of Komatsu,a Japanese �rm, each truck is the size of athree-storey house and uses satellite posi-tioning to carry nearly 300 tonnes of orealong prede�ned routes. An accident, then,could be very nasty indeed. But James Pet-ty, head of Rio Tinto’s robotic-trucks pro-gramme, says the trucks’ emergency-brak-ing and evasive-action systems have notbeen triggered once since the technologywas introduced in 2008.

One reason is that as well as using theusual plethora of sensors, the trucks in-form each other of their position andspeed using �vehicle to vehicle� (V2V)wireless links, so that they can, for exam-ple, co-ordinate their actions at junctions.Human truck-drivers, by contrast, regular-ly have to take evasive action. They also de-mand salaries of around A$100,000($100,000) to work in the remote Pilbararegion of Western Australia.

Initially, driverless vehicles will be in aminority, but eventually it may makesense to redesign road networks aroundthem. Using V2V communication, for ex-ample, driverless cars approaching a junc-tion could co-ordinate their movements tokeep tra�c �owing smoothly, rather thanhaving to stop and take turns. Tra�c lightsand road signs would no longer be needed.V2V would also allow vehicles to travel to-gether in platoons or �road trains�, makingmore e�cient use of road capacity.

A consortium of European companieshas tested �ve-vehicle platoons in whichthe lead vehicle is controlled by a humandriver and the other four travel close be-hind it under autonomous control. Trialsincluding a 200km trip on a motorwaynear Barcelona in May have found that pla-tooning cuts fuel consumption by about15%, because each vehicle (apart from thelead vehicle) travels in the slipstream of

the one in front. Passengers �nd the prox-imity unnerving at �rst, but they quicklyget used to it, says Eric Chan of Ricardo, theBritish technology �rm leading the project.

Clearly, a shift towards driverless carswould completely transform the experi-ence of road travel. But there would be fur-ther knock-on e�ects beyond the car itself.Self-driving vehicles would keep thegrowing numbers of elderly people in age-ing societies mobile for longer, for exam-ple. The design of cars would undoubtedlychange: if the controls are rarely needed,steering wheels and pedals will vanish,and cars will be built instead for comfort,perhaps with a PlayStation-like controllerthat pops out on the rare occasions whenmanual control is needed.

The nature of car ownership could betransformed. Why own a car outright ifyou can rent or share more cheaply, sum-moning a nearby vehicle with your smart-phone? You could be picked up by a vehi-cle while its owner works or sleeps, saysSebastian Ballweg, co-founder of Auto-netzer, a German �car-sharing� broker ofhourly or daily rentals between private in-dividuals. Some people regard their choiceof car as an important means of social sig-nalling, but fractional or shared ownershipmight be cheaper and more convenient.

The rise of driverless cars would alsoa�ect the planning and layout of cities. As-suming that autonomous vehicles makejourneys quicker and use road space moree�ciently, how should planners exploitthe bene�ts of automation? On the onehand it would allow cities to get bigger, byreducing the time and stress associatedwith commuting. On the other, it could al-

low cities to become denser, by reducingthe amount of space that needs to be dedi-cated to roads and parking. Alternatively,space allocated to roads in city centrescould be used for bike lanes or parks.

If driverless vehicles are to becomecommonplace, several problems must besolved, aside from working out how tobuild them in the �rst place. Appropriateregulation will be needed to ensure safetyand reassure other road users. In America,Nevada has taken the lead in this regard. InMay the state’s Department of Motor Vehi-cles (DMV), based in Carson City, issued its�rst three autonomous-vehicle licences toGoogle. Applications from two other �rmsare expected soon. Licences are issued oncondition that applicants post a $1m bond.This is intended to prevent tinkerers from�building a little project in their garage andjumping on the road� and causing an acci-dent, says Bruce Breslow, the head of Neva-da’s DMV. The state also requires that ro-botic vehicles have �black boxes� thatstore the previous 30 seconds of camerafootage and sensor data to establish who,or what, is at fault in the event of an acci-dent. Other states are passing similar laws.

There are additional worries. Vehicle-control software remains �fairly hack-able�, says David Zuby, chief researcher atthe Insurance Institute for Highway Safety,an American industry body. Unless proto-cols for vehicle-to-vehicle communicationare robust and secure, attackers couldcause chaos by making cars crash into eachother. John Simpson, a privacy advocate atConsumer Watchdog, a California lobbygroup, is concerned that Google is not somuch teaching computers to drive as it ispioneering a nightmarish form of advertis-ing. Google might be tempted, for a fee, tofavour routes that lead past its advertisers.He presented his case in June in testimonyto the transportation committee of Califor-nia’s state assembly.

And although driverless cars can be ex-pected to reduce the number of accidentsand road deaths, they will not eliminatethem altogether. It is only a matter of timebefore the maker of an autonomous vehi-cle is sued for unleashing a killer robot,says Michael Toscano, head of the Associa-tion for Unmanned Vehicle Systems Inter-national, an industry body in Arlington,Virginia. But if self-driving cars really aresafer than cars driven by humans, the lawcould work in their favour, too. Some citiesmight ban manual driving, to save livesand ease congestion. There is no doubt thatself-driving cars are coming. It is less clearwhere they will take us. 7

The shape of things to come

�Driverless vehicles could transform car design,rede�ne car ownership and a�ect urban planning.�

The Economist Technology Quarterly September 1st 2012 Phase-change memory 15

AS EVERY parent knows, a tidy bedroomis very di�erent from a messy one. The

number of items in the room may be exact-ly the same, but the di�erence between or-derly and disorderly arrangements is im-mediately apparent. Now imagine a housewith millions of rooms, each of which is ei-ther tidy or messy. A robot in the house caninspect each room to see which state it is in.It can also turn a tidy room into a messyone (by throwing things on the �oor at ran-dom) and a messy room into a tidy one (bytidying it up). This, in essence, is how a newclass of memory chip works. It is called�phase-change memory� and, like the�ash memory that provides storage in mo-bile phones, cameras and some laptops, itcan retain information even when thepower is switched o�. But it promises to besmaller and faster than �ash, and willprobably be storing your photos, musicand messages within a few years.

The technology relies, as its name sug-gests, on special substances called phase-change materials (PCMs). These are mate-rials, such as salt hydrates, that are capableof storing and releasing large amounts ofenergy when they move from a solid to aliquid state and back again. Traditionallythey have been used in cooling systemsand, more recently, in solar-thermal powerstations, where they store heat during the

day that can be released to generate powerat night. But for memory devices it is nottheir thermal properties that make PCMsso attractive. Instead it is their ability toswitch from a disorderly (or amorphous)state to an orderly (or crystalline) one veryquickly. PCM memory chips rely on glass-like materials called chalcogenides, typi-cally made of a mixture of germanium, an-timony and tellurium.

Each cell in the memory chip consistsof a region of chalcogenide sandwichedbetween two electrodes (see diagram onnext page). The bottom electrode is a resis-tor that heats up when a current passesthrough it. Delivering a gentle pulse ofelectrical energy to the cell turns on thistiny heater and causes the chalcogenide tomelt. As it cools it forms an orderly, crystal-line structure. This state corresponds to thememory cell storing a �1�. Applying a shor-ter, stronger pulse of energy to the cellmelts the chalcogenide but does not allowcrystals to form as it cools. Instead, the re-gion of the material above the bottom elec-trode assumes a disorderly, amorphousstate, corresponding to the cell storing a�0�. The amorphous state has a higherelectrical resistance than the crystallinestate, allowing the value stored in the cellto be determined. (For this reason PCM

memory is sometimes called �resistive

memory�, and its individual cells aresometimes referred to as �memristors�.)

You may already be relying on chalco-genides to store data without realising it,because they are used in re-writeable opti-cal storage, such as CD-RW and DVD-RW

discs. Bursts of energy from a laser put tinyregions of the material into amorphous orcrystalline states to store information. Theamorphous state re�ects light less e�ec-tively than the crystalline state, allowingthe data to be read back again. The technol-ogy has, in other words, already provedthat it can work. Now companies like Mi-cron Technology, Samsung and SK Hynix�the three giants of digital storage�are ap-plying it inside memory chips. The tech-nology has worked well in the laboratoryfor some time, and has been used in ahandful of specialist applications since2007. But it is moving towards the main-stream consumer market. Micron startedselling its �rst PCM-based memory chipsfor mobile phones in July, o�ering 512-megabit and one-gigabit storage capacity.

Thanks for the memoriesPCM memory chips have several advan-tages over �ash memory, which works bytrapping electrons in an enclosure called a��oating gate�, built on top of a modi�edform of transistor. The value stored in eachcell is 1or 0, depending on whether the en-closure is full or empty. But writing to indi-vidual �ash-memory cells involves eras-ing an entire region of neighbouring cells�rst. This is not necessary with PCM mem-

Altered states

Computing: Phase-change memory chips, an emerging storage technology,could soon dethrone �ash memory in smartphones, cameras and laptops

1

16 Phase-change memory The Economist Technology Quarterly September 1st 2012

2 ory, which makes it much faster, says PaoloGiuseppe Cappelletti, who is in charge ofMicron’s PCM memory project at AgrateBrianza in Italy. Indeed, some prototypePCM memory devices can store and re-trieve data 100 times faster than �ashmemory, says Evangelos Eleftheriou, headof storage technologies at IBM’s Zurich Re-search Laboratory in Switzerland.

Another bene�t of PCM memory is thatit is extremely durable, capable of beingwritten and rewritten at least 10m times.Flash memory, by contrast, wears out aftera few thousand rewrite cycles, because ofthe high voltages that are required to shep-herd electrons in and out of the �oating-gate enclosure. Accordingly, �ash memoryneeds special controllers to keep track ofwhich parts of the chip have become unre-liable, so they can be avoided. This in-creases the cost and complexity of �ash,and slows it down.

In addition, PCM o�ers greater poten-tial for future miniaturisation than �ash.As �ash-memory cells get smaller and de-vices become denser, the number of elec-trons held in the �oating gate decreases.Because the number of electrons is �nite,there will soon come a point at which thisdesign cannot be shrunk any further, saysTom Eby, the head of Micron’s embeddedsolutions group. �We need a fundamental-ly di�erent approach,� he says. Last year agroup led by Eric Pop at the University of Il-linois, Urbana-Champaign, demonstratedhow a prototype PCM memory cell couldbe made that was just 10 nanometresacross, bridging a gap between two car-bon-nanotube electrodes. The research,published in the journal Science, alsoshowed marked improvements in energyconsumption compared with �ash.

As well as allowing for smaller cellsizes, PCM memory could pack in moredata by storing more than one binary digitin each cell. Some �ash-memory devicesalready do this, using a trick called �multi-level cells� (MLC). Instead of each �oatinggate being either full or empty, two inter-mediate states are also used. There arethen four states in total, which are taken torepresent 00, 01, 10 and 11, rather than justthe usual 0 and 1. Two binary digits, or bits,are then held in each cell, doubling the ca-pacity of the memory. Similarly, increasingthe number of states to eight allows each tohold three bits. But this trick will becomeeven trickier to pull o� as memory devicesget smaller. Today’s �ash-memory cellshave only a few dozen electrons in the�oating gate when full. �Currently a fewtens of electrons are used to di�erentiate

between various programmed states inMLC �ash,� says Haris Pozidis of IBM. Heand Dr Eleftheriou have been applying themulti-level idea to PCM memory.

This involves careful control of thelength of the energy pulse that creates anamorphous region in the memory cell. Ashorter pulse creates a smaller amorphousregion. The smaller the region, the lowerthe electrical resistance of the cell. It istherefore possible to get a single cell tostore multiple bits. Precisely how many re-mains to be seen. The IBM researchershave built PCM memory chips with 16states (or four bits) per cell, and DavidWright, a data-storage researcher at theUniversity of Exeter, in England, has builtindividual PCM memory cells with 512states (or nine bits) per cell. But the largerthe number of states, the more di�cult itbecomes to di�erentiate between them,and the higher the sensitivity of the equip-ment required to detect them, he says.

Catch my drift?There is also the problem of drift. This iswhere the resistance of a cell changes grad-ually in the days and weeks after its statehas been updated. For a single-bit cell thisis not a problem, because the di�erence in

resistance between its possible two statesis large, so a small variation does not reallymatter. But for multi-level cells drift caneventually cause errors. To make mattersworse, the amount of drift is non-linear,says Dr Eleftheriou, and depends on howlarge the amorphous region is.

But the IBM researchers think they havehit upon a solution, by modifying the waycells are written to and read from. Whenwriting a value into a cell, the cell’s resis-tance is measured after the energy pulse isapplied, and more pulses are applied ifnecessary to ensure that the �nal resis-tance is set precisely to the appropriate val-ue. Even in the worst-case scenario inwhich multiple pulses are needed, writingto the PCM memory is still 100 times fasterthan writing to �ash. This approach alsomakes up for slight variations in the resis-tance of di�erent cells in a PCM memory.

In addition, the IBM researchers de-vised a �drift-tolerant� method to read thevalue in a cell, by reading multiple cells si-multaneously and comparing their rela-tive values to determine the state of eachone. They have also developed a way tomeasure the thickness of the amorphousregion more accurately by analysing itselectrical properties when a known cur-rent is passed through it. Drift causes the re-sistance of a cell to change, but not thethickness of the amorphous region, so thisprovides a more robust way to measurethe cell’s state.

IBM is now working with SK Hynix tobring multi-level PCM-based memorychips to market. The aim is to create a formof memory capable of bridging the gap be-tween �ash, which is used for storage, anddynamic random-access memory, whichcomputers use as short-term workingmemory, but which loses its contentswhen switched o�. PCM memory, whichIBM hopes will be on sale by 2016, wouldbe able to serve simultaneously as storageand working memory�a new category itcalls �storage-class memory�.

This in turn could open the door to newcomputer architectures in which informa-tion does not have to be shued from rela-tively slow storage devices to much fasterworking memory. Such architectureswould be capable of crunching hugeamounts of information, such as the datathat will be gathered by the Square Kilo-metre Array telescope, far more e�cientlythan existing machines, says Dr Elefthe-riou. PCM memory does not merely threat-en to dethrone �ash, in short. It could alsolead to a radical shift in computer design�aphase change on a much larger scale. 7

How phase-change memory works

Amorphouschalcogenide

Just a phase I’m going through

Source: The Economist

1. Each memory cell consists of a glass-like material called a chalcogenide, sandwiched between two electrodes. Delivering a gentle pulse of electrical energy to the cell causes the chalcogenide to melt and then solidify into an orderly, crystalline structure. This state corresponds to the memory storing a “1”.

Top electrode

Crystallinechalcogenide

2. Applying a shorter, stronger pulse of energy to the cell melts the chalcogenide without letting crystals form as it cools. Instead, a region of the material assumes an amorphous state, corresponding to a “0”. The amorphous and crystalline states have a different electrical resistance, allowing the state of the cell to be read.

3. The latest trick in phase-change memory is to control the size of the amorphous region that forms when a value is written into the cell. With three different-sized regions plus a pure crystalline state, the cell has four possible states in all, allowing it to store two binary digits (bits) instead of just one.

Bottomelectrode(heater)

�As well as dethroning �ash, phase-change memorycould lead to a radical shift in computer design.�

The Economist Technology Quarterly September 1st 2012 Brain scan 17

IT TOOK just 20 minutes to build, butChris Soghoian’s hastily constructed

website capable of generating fake airlineboarding passes led to a rebuke from acongressman, a raid by the Federal Bureauof Investigation (FBI), an investigation bythe Transport Security Administration(TSA), worldwide media coverage�andultimate vindication. With a series ofsimilar exploits that have exposed securi-ty �aws and privacy violations, he hasdemonstrated his ability to hack the me-dia with just as much facility as he manip-ulates computers. At the age of 30 he hasestablished himself as the most promi-nent member of a new generation ofactivist technology researchers who de-light in causing a media stink in order toshame companies and governments into�xing problems with their systems.

The boarding-pass example occurredin 2006, when Dr Soghoian, then a gradu-ate student at the University of Indiana,became irritated by an obvious �aw inairport procedures used by TSA screeners.Although screeners checked the name oneach passenger’s boarding pass against agovernment-issued identity document,they had no way of verifying that theboarding pass itself was valid. Fake board-ing passes could easily be created for any�ight using a computer and image-ma-nipulation software, as had already beenpointed out by Bruce Schneier, anothersecurity guru, in 2003. Charles Schumer, asenator, even issued a press release inFebruary 2005 explaining how easilysecurity could be bypassed in this way.

Yet it took Dr Soghoian to light the rightkind of �recracker under this knownproblem. In October 2006 he threw to-gether a web page that could generate fakeboarding passes for Northwest Airlinesthat appeared valid to TSA screeners. Thepage received enormous press attention,even though he never printed out or useda false pass himself. Ed Markey, a congress-man, called for Dr Soghoian’s arrest. TheFBI had his website shut down and seizedhis computers. The TSA opened an inqui-ry. But when the simplicity of the �hack�became apparent, along with Dr Sogh-oian’s academic status, Mr Markey apol-ogised and suggested that rather thaninvestigating Dr Soghoian, the TSA should

hire him instead. Dr Soghoian’s computerswere returned a few weeks later and theTSA investigation was closed. This yearthe TSA �nally began testing equipment tovalidate boarding passes at airports.

Dr Soghoian has since perfected thismodus operandi and used it to exposeproblems with internet encryption, onlineprivacy and electronic surveillance. Ineach case he identi�es a problem, creates atechnology demonstration to highlight itand sometimes �les Freedom of Infor-mation Act requests or complaints togovernment agencies. He then presentsthe results neatly packaged for the newsmedia. The organisations targeted by DrSoghoian usually start o� by accusing himof being mistaken or naive, before ad-mitting that he is right and modifying theirpolicies, or issuing a statement saying thata �x was already in the works.

Dr Soghoian has, among other things,revealed the extent to which Sprint, anAmerican telecoms operator, was dis-closing its customers’ satellite-positioningdata to law-enforcement agencies;shamed Google, an internet giant, intoupgrading its encryption; exposed a woe-fully misguided attempt to attack Googleby a public-relations �rm hired by Face-book, a rival internet giant; embarrassedDropbox, a provider of online �le-storage,over its marketing claims and technicalpractices; and pushed for the adoption ofa �Do Not Track� scheme to allow internetusers to opt out of targeted advertising.�Every privacy scandal essentially has totake the form of a �restorm,� says DrSoghoian. �I try to focus on things that arereally important that haven’t gottenenough attention.� He is now campaign-ing against the widespread trawling ofinternet tra�c by law-enforcement agen-cies, calling instead for a more targetedfocus on speci�c cases or leads.

The FBI made me do itHaving grown up surrounded by comput-ers (his father used to be a software engi-neer), Dr Soghoian says he slid into com-puter science without even consideringother disciplines. He became interested incomputer security in particular during hisundergraduate studies, and was thendrawn to the specialised �eld of privacy.But it was only when the FBI raided hishome in 2006 and his PhD adviser sug-gested that he take a law class that DrSoghoian decided to concentrate on theintersection between computing and thelaw. He wrote his thesis on governmentaluse of third parties to monitor electronic

A knight in digital armour

Chris Soghoian, the most prominentof a new breed of activist technologyresearchers, delights in exposingsecurity �aws and privacy violations

1

18 Brain scan The Economist Technology Quarterly September 1st 2012

communications and was awarded hisdoctorate in July 2012.

But it would be wrong to characteriseDr Soghoian simply as an academic or anactivist, because he has an unusual gift forworking outside conventional institution-al strictures. While completing his PhD, hewas also attached to America’s FederalTrade Commission (FTC) as a technicaladviser. This came about as a result of DrSoghoian’s support for the �Do Not Track�standard, and his e�orts to make it easierfor people to prevent their use of theinternet being tracked by advertisers.Turning such tracking o� can be quitetricky, and must be done for multiplegroups, or networks, of advertisers.

This prompted Dr Soghoian to developtwo add-ons for the Firefox web browserthat demonstrated simple ways to turn o�tracking automatically. The �rst manipu-lated �cookies�, the tiny snippets of infor-mation stored by web browsers, to disabletracking. The second, developed with thehelp of Sid Stamm, a programmer, sends aspecial message with every page requestasking that the user not be tracked. DrSoghoian got the idea for this approachfrom Dan Kaminsky, a security researcher.But it will work only if websites are re-quired to detect and act on such messages.At �rst this suggestion was ridiculed. In2009, however, Dr Soghoian was contract-ed by the FTC to provide lawyer-to-geektranslation for its sta�. In this role he wasable to garner support for his �Do NotTrack� scheme within the FTC, and tech-nology �rms including Microsoft andTwitter have subsequently backed it. Theadvertising industry dislikes it, but seemsresigned to accepting it in some form.

A few months after joining the FTC DrSoghoian recorded a Sprint executivespeaking at a surveillance trade showattended by telecoms �rms, law-enforce-ment agencies and equipment-makers.The executive explained that Sprint hadbuilt an automatic system that had provid-ed 8m lookups of customers’ locations inthe preceding year in response to requestsbacked by court orders. (Sprint said laterthat a single court order could generateseveral thousand lookups.) Dr Soghoianbriefed the press and posted the audioonline. He insisted that he was doing so inhis role as a graduate student, rather thanan FTC contractor. The scale of trackingcaused a furore that persists three yearslater about the ease and scale of mobile-phone surveillance. When Dr Soghoian’s�rst year at the FTC was up, the agency didnot renew his contract. He blames the fuss

caused by the Sprint recording. (The FTC

will not comment.)Dr Soghoian is one of a group of re-

searchers, some of whom are a�liatedwith academic institutions and many ofwhom work together, who have risen toprominence by showing how tedioustechnical �aws can a�ect ordinary people.Ashkan Soltani, who like Dr Soghoian hasworked as an adviser to the FTC, hasshown how some companies have de-vised �evercookies��cookies that are verydi�cult to eradicate. Along with JonathanMayer of Stanford Law School, he showedhow Google was bypassing tracking pref-erences in Apple’s web browser, Safari,which resulted in Google having to pay a$22.5m �ne. Mr Kaminsky spotted a huge�aw in the internet’s addressing system in2008, and then worked closely with largetechnology �rms to �x it. And Mr Stammis now a privacy advocate at the MozillaFoundation, which oversees the devel-opment of the Firefox web browser.

First among equalsThese researchers insist they are actingsolely in the interest of protecting individ-ual privacy. They are certainly not in it forthe money. Dr Soghoian has spent threeyears living the life of an aesthete in Wash-ington, DC, where he rides a bicycle andresides in the basement of a house heshares with four other people. �There areso many events with free food and drinkthat you never need to buy anything toeat,� he says. After his funding from theUniversity of Indiana ran out in 2008, DrSoghoian received several grants andfellowships. He gleefully points out thevaried political leanings of his patrons. Hehas received some funding from the liber-tarian-leaning Institute for Humane Stud-ies (IHS), backed by the arch-conservativeCharles Koch. But as he moved to investi-gate business misdeeds rather than thoseof government, the IHS money was re-placed by a fellowship from the OpenSociety Foundations, a group run by MrKoch’s nemesis on the left, George Soros.That funding ended in July.

Can Dr Soghoian’s reputation as aknight in digital armour be squared withhis obvious �air for self-promotion? Yes,says Jules Polonetsky, director of the Fu-ture of Privacy Forum, a think-tank basedin Washington, DC, who by his own ad-mission does not always see eye-to-eyewith him. �People would be surprised bythe number of times that this otherwisevery public media bomb-thrower hasquietly worked to get a company to simply

solve a problem when it could have beena front-page story,� says Mr Polonetsky. DrSoghoian’s agenda is �not about money,not about fame or anything like that,� saysLee Tien of the Electronic Frontier Founda-tion, a lobby group with which Dr Sogh-oian sometimes collaborates. He just usesthe glare of the media to get results.

Though known for his strong views onprivacy and surveillance, Dr Soghoian isno absolutist. In April he published apaper in the Berkeley Technology Law

Journal on how best to grant law-enforce-ment agencies access to individuals’ loca-tion data, with proper checks and bal-ances. It was co-written with StephaniePell, who was on the Department of Jus-tice team that prosecuted people accusedof being linked to al-Qaeda. Writing thepaper, says Dr Soghoian, involved �ndinga balance between Ms Pell’s knowledge ofthe utility of location-tracking in lawenforcement and his own concerns aboutunwarranted privacy intrusions. �Themarginal cost of spying on one moreperson is essentially zero now,� he says.�The economics of modern surveillanceare not bene�cial to the consumer.�

As a respite from his campaign to de-fend personal privacy, Dr Soghoian likes togo to India. But he may have to �nd some-where else to holiday. �India is rapidlybecoming a surveillance state,� he says.Such trips may be less frequent in anycase, because Dr Soghoian now has a newjob at the American Civil Liberties Union,mediating between geeks and lawyers, ashe did at the FTC. His new employersmust be well aware that they have cap-tured lightning in a bottle�and should notbe surprised when it escapes. 7

�The economics of modern surveillance are not bene�cial to the consumer.�

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