15-829B/18-849B/95-811A/19-729AInternet-Scale Sensor Systems: Design and Policy

Lecture 3 – Code Overview & Project Ideas

Lecture 3 201-21-03

Outline

Code Overview

Project Ideas

Lecture 3 301-21-03

Code Availability

http://www.intel-iris.net Code accessible via CVS

What is CVS version control system Useful for group access to source code Multiple people can edit the same file but conflicts may

occur

Anonymous CVS can’t check in code

Lecture 3 401-21-03

Mailing-lists

Class members irisnet-course@intel-iris.net

Iriscode developers irisdev@intel-iris.net

Managed by majordomo@intel-iris.net

Lecture 3 501-21-03

Using Laptop

Laptop setup irisnet and root account passwords = irisnet

Feel free to customize account but don’t change password IrisNet source code checked out in ~irisnet/IRISNET Redhat 8.0

Boot with camera attached Say configure at all the configuration prompts

Log in as irisnet Start X server Network configuration

System settings network Add… wireless lucent SSID = CMU Activate Start browser with outside CMU URL register wireless

Lecture 3 601-21-03

Building IrisNet

cd IRISNET export CVS_RSH=ssh cvs login

password = anonymous cvs up -d -P ./install

Should build without error Try test suite

cd ~/IRISNET/TestSuite; ./testall.sh

Lecture 3 701-21-03

Components

SA C-based Base SA code OpenCV CamStream webcam viewer

OA Java-based Base OA code Apache Xindice XML database

Logger NAM network simulation animator

Applications

Lecture 3 801-21-03

SA Architecture

Shared Memory

SA Daemon

Sensor Feed

Senselet

Senselet

Senselet

Network

Lecture 3 901-21-03

SA – Sensor Feed

Read from sensor and place info in shared memory One process per sensor

Sensor readings are stored in circular buffer Provides access to historical measurements

as space permits

Lecture 3 1001-21-03

SA – Starting the Sensor Feed

cd SA/IrisWebcam ./runwebcam.sh to use real camera ./loadImage to load one image

./loadImage images/pX.jpg 75 X = number of full spots = 0..6 75 = shared memory key for IrisNet

./loadImages to cycle through files in images subdir

./showImage shows the current image

Lecture 3 1101-21-03

SA – CamStream

CamStream provides an interface to webcams and a bunch of useful tools E.g., webcam capture/record

Needs gcc 2.95 (not installed on laptops) to compile completely Gcc 3.2 only compiles the few libraries critical to

IrisNet

Lecture 3 1201-21-03

SA – Senselet

Senselet One senselet per sensor service Each senselet runs as a separate process

Senselet typically does:1) take sensor data from shared memory

2) processes data to produce result

3) Transmits result to configured OA

4) Results may be stored back in shared memory

Lecture 3 1301-21-03

SA – Running Senselet

./SAControl 127.0.0.1 3456 “S 127.0.0.1 6789 parking” executes parking detection senselet Need to first run “Util/Portsink/portsink 6789” to

discard data Can load new images to see changes in result Can use similar technique to test your code for

mini-project

Lecture 3 1401-21-03

SA – Example Senselet

cd Applications/parking/SA parking.cc contains parking space senselet Main function called Start(FilterParameter param) Typical structure of main function

Open shared memory cvCreateImageHeader and cvSetImageData calls retrieve

video image openCV calls to process image data Send data to the OA

Lecture 3 1501-21-03

SA – SA Daemon

Manages the execution of senselets Accepts commands from OAs to start/stop execution

Text-based command protocol (port #3456) L <OA_IP> <OA_PORT> <senselet filename> <senselet

name> <senselet code> uploads the code for a senselet and places it in filesystem

S <OA_IP> <OA_PORT> <senselet name> starts execution of a senselet and transmits output to

specified OA U <OA_IP> <OA_PORT> <senselet name>

stop execution of a senselet

Lecture 3 1601-21-03

SA – SA Daemon

Starting cd SA/IrisSA/src ./runsa

Controlling Normally controlled by OA’s cd Util/SAControl ./SAControl to manually send commands

Lecture 3 1701-21-03

OA - Architecture

Xindice OA Daemon Network

Lecture 3 1801-21-03

OA – Xindice

What does it do? Local XML database engine Stores XML documents, handles Xpath 1.0 (mostly select and

update) Interfaces

Command line enter Xpath Java API

What doesn’t it do [well] Xquery, XSLT XSLT processing done in separate Java library Image storage

How do we use it Each service has a single XML document that stores sensor

readings and static metadata

Lecture 3 1901-21-03

OA – Starting Xindice

cd packages/xml-xindice-1.0 ./xindice.server start

Make sure that config/xindice.pid does not exist export XINDICE_HOME=`pwd` cd packages/xml-xindice-1.0/bin Run ./xinidiceadmin to control database

Lecture 3 2001-21-03

OA – OA Daemon

Listens on port 6789 Handles processing/forwarding of queries

Uses XSLT to query Xindice database Manages partitioning of database across

nodes DNS entries Reaction to load

Lecture 3 2101-21-03

OA – OA Daemon Messages

Query <srcPort> <id> <fragment #> <root> <Xpath query> Process the XPath query, id identifies source query made at root,

fragment identifies this particular subquery Reply <id> <fragment #> <replying OA> <response>

Answer to a query Take ownership <schema>

Start a new OA Delegate ownership <targetIP> <targetPort> <Xpath query>

Split an OA Delete database <database name> Load data from SA <num xupdates> <xupdates>

Used by SAs to add to database Update DNS <database name>

Use dynamic DNS

Lecture 3 2201-21-03

OA – OA Daemon

Running cd OA/IrisOA Edit oa.cfg if needed make run

Controlling make runcl

Type help to see interface Running a Service

cd Applications/parking/OA Look at demodataone.xml Follow handout instructions to load xml document

Lecture 3 2301-21-03

Logging

What are the OAs/SAs doing? Log all messages currently uses a central

server Challenge: how to order and playback log

messages Lamport clocks to ensure causal order ns-2 network animator (nam) used to playback

log What is nam?

Lecture 3 2401-21-03

Logging

Running the logger cd logger/IrisLogger/src runnam.sh

Running NAM cd logger/nam-1.0a11a_iris ./nam ../IrisLogger/src/logfile.6

Currently logging must be carefully tuned to the application manual steps involved: Name and layout of nodes in animation Conversion of logfile node names to nam nodes identifiers

Lecture 3 2501-21-03

Outline

Code Overview

Project Ideas

Lecture 3 2601-21-03

Projects

2 or 3-person groups IrisNet-based

Mini-project provides intro to IrisNet Expectations

10 page report + presentation Workshop quality results

Project ideas Will be posted on Web pages

Lecture 3 2701-21-03

Projects (cont.)

Generous donation from Intel 20 laptops + cameras 10 desktops

Each project group will receive 2 laptops and 3 cameras Handed out TODAY in CMCL lab 3604 Wean Hall

Only to enrolled students, other students will need to wait No replacements – take good care of them No grade until you return them in good condition!

Interesting deadlines Sensys – Apr 8th

Mobicom workshops – June middle

Lecture 3 2801-21-03

Applications – Monitoring Interesting Places

At lunch places At grad lounge foosball table NSH Atrium Find me a free conference rooms Tennis/raquetball/etc. court avail Desk area/terminal room availability Car theft monitor

Call/email owner if thief is near car! Traffic monitoring

Auto traffic (traffic jams) Throughput of area (cars, people) - speed trap

Lecture 3 2901-21-03

Applications – Object Tracking

Person tracking Where did my child/pet go Advisor/advisee avoidance Location of my/someone else's car Inventory control

Lecture 3 3001-21-03

Other Service Types

Audio sensor-based applications Identify language spoken Identify individual based on voice Triggered sensor applications

Record picture when car horn is heard

Network monitoring as an IrisNet application Intrusion detection system

Lecture 3 3101-21-03

Other Service Types – Environment Modeling

Smart room support 3d positioning based on multiple sensors

Virtual reality tour Take the sensor input to create parts of a virtual

reality Weather monitoring

Lecture 3 3201-21-03

Applications – General Challenges

Image processing How do you identify objects of interest? Person/object counting techniques

Motion detection based

Identifying the same object in different views Handoff of tracking data from one sensor to next

Lecture 3 3301-21-03

Applications – General Challenges

Privacy issues Access control to OA database How does a person opt out of a surveillance

Query processing What type of data schema for sensor readings? How are historic queries handled Data mining

Long term trends – e.g., in parking space availability or waiting lines

Lecture 3 3401-21-03

Infrastructure

Incorporating new sensor types in IrisNet infrastructure Sensor motes – how do you modify the SA programming

model to accommodate motes? Others: mobile sensors, public webcams, smart camera

phones Making IrisNet infrastructure robust to failures

Replicating part of database How to handle dynamic vs. static parts of database

Handling failures in routing of queries – e.g., due to caching?

Distributed monitoring of system and on-demand collection of logs

Lecture 3 3501-21-03

Infrastructure – Energy Constraints

Power management for local processing, e.g., how accurately can we predict energy consumption?

What is the energy tradeoff between local processing of data vs. sending the data to do remote processing?

Running a CPU, a sensor device, or a communication device in sleep mode can save energy considerably. An approach for saving power is thus to operate our devices mostly in sleep mode, and have them turn on periodically. How much accuracy does our sensor data loose

given some duty cycle? Can we find more intelligent scheduling algorithms than simply

uniform duty cycles (on during 100ms each second)? What about using low-energy sensors to schedule more

power-hungry sensors?

Lecture 3 3601-21-03

Infrastructure

Location-based services How could we incorporate location-specific

information in our sensors? How could we establish or verify the location of a

sensor? Using video landmarks

Image Processing Can we anonymize raw sensor feed – e.g., by

blurring people in image

Lecture 3 3701-21-03

Infrastructure – Policy/Security

How can a user ensure that a video feed has not been “misused”? E.g., monitor the output XML, perform test queries on

system Assuming an open environment (i.e., no central

certificate authority everybody trusts), how can we establish trust between unrelated entities?

How do we ensure that sensor data we receive is trustworthy and originates from the correct sensor?

If anyone can make queries/program sensors, how do we protect the system from a denial-of-service attack?

Lecture 3 3801-21-03

Infrastructure

DNS Performance evaluation DHTs as an alternative

Code safety and resource allocation on SAs/OAs How are services protected from each other How are nodes protected from malicious services that

consume resources

Storage use on SAs Support for historic sensor reading retrieval Impact on result sharing

Lecture 3 3901-21-03

Infrastructure

Push vs. Pull of data Impact on monitoring of failed nodes Impact on caching/response time for queries

Handling aggregate fields in OA database

Lecture 3 4001-21-03

Next Lecture

Image processing OpenCV library Assigned reading:

TBA