ijess complimentary copy vol1issue3

IJESS Volume1Issue3 ISSN: 2249‐ 9482

International Journal of Engineering & Social Sciences www.gjmr.org

Sr.

No.

TITLE & NAME OF THE AUTHOR(S) Page

No.

1 MEASURING SOFTWARE QUALITY FACTORS USING CK METRICS

Rashmi Goyal, Sona Malhotra

1

2 INDIAN REAL ESTATE‐ A BOON TO THE ECONOMY

Dr. V. Santhi, Benon.S, Arun Kumar.J

10

3 WIRELESS SIGNAL STRENGTH ENHANCEMENT IN LOCAL AREA NETWORK (WLAN)

M. Umair Saleem, Tasleem Mustafa, Ahsan Raza Sattar, Dr. Muhammad Saleem, Dr. Shaukat Ali

28

4 SECURITY IN VEHICULAR AD‐HOC NETWORKS ‐ CHALLENGES AND COUNTER MEASURES

Ann Baby, .Dr.Sreekumar

45


International Journal of Engineering and Social Science www.gjmr.org 1

MEASURING SOFTWARE QUALITY FACTORS USING CK METRICS

Rashmi Goyal*

Sona Malhotra**

ABSTRACT

This paper gives an approach to evaluate software testability. The process of Software

Engineering evolves with a unique issue of testability. It is an external software attribute that

assesses the complexity and effort required for testing software. The insight provided by

testability is valuable during design, coding, testing and quality assurance. To capture

testability of classes, we used different metrics to measure its characteristics. Testability

Keywords: Software Testability, CK metrics, quality.

*CSE Deptt., University Institute of Engineering & Technology, Kurukshetra

** Assistant Professor, CSE Deptt., University Institute of Engineering & Technology,

Kurukshetra



1. INTRODUCTION

Software engineering is a profession dedicated to analysis, designing, implementing and

modifying software so that we develop software of high quality and fast to build. Testing has

always been a broad concept to measure and evaluate software accurately. Software quality is the

attribute to measure the software characteristics. To measure software quality, a no. of software

metrics is used. Metric are the quantitative measure of the degree to which a system, component,

or process possesses a given attribute. Software metrics can be used to measure different

characteristics of a software system or software development process. Metrics for object oriented

development is a relatively new field of study. The metrics focus on internal object structures

that reflect the complexity of each individual entity, such as methods and classes, and on external

complexity that measures the interactions among entities, such as coupling and inheritance.

Chidamber and Kemerer’s metrics suite for object-oriented design is the deepest research in OO

metrics investigation. They have defined six metrics for OO design.

2. CK METRICS

Weighted methods per class (WMC):

It is the sum of the complexities of all methods of a class. According to this metric if a Class C,

has n methods and c1, c2 …cn be the complexity of the methods, then WMC(C)= c1 + c2 +… +

cn. Mc Cabe’s complexity metric is chosen for calculating the complexity values of the methods

of a class. The value is normalized so that nominal complexity for a method takes on a value of

1.0. If all method complexities are considered to be unity, then WMC = n i.e. the number of

methods existing in that class.

Depth of the inheritance tree (DIT):

Depth of inheritance of a class is “the maximum length from the node to the root of the tree".

More is the depth of the inheritance tree greater the reusability of the class corresponding to the

root of that tree as the class properties are shared by more derived classes under that class. So

there too much depth dilutes the abstraction. So there is a need to set the minimum & maximum

DIT value for a class as a contribution towards the reusability.



The definition of DIT is ambiguous when multiple inheritance and multiple roots are present as

the alternative length of the path is not being considered in case of multiple inheritance. If we

add all the ancestor classes coming in common path to the ancestor classes coming in alternative

paths then that will be the true representation of the theoretical basis of the DIT metric.

Number of Children (NOC):

According to this metric Number of children (NOC) of a class is the number of immediate sub-

classes subordinated to a class in the class hierarchy. So greater is the value of NOC greater will

be the reusability of the parent class. Hence there should be some minimum value of NOC for a

parent class for its reusability. Theoretical basis of NOC metric relates to the notion of scope of

properties. It is a measure of how many sub-classes are going to inherit the methods of the parent

class. The definition of NOC metric gives the distorted view of the system as it counts only the

immediate sub-classes instead of all the descendants of the class. NOC value of a class, say class

i, should reflect all the subclasses that share the properties of that class.

NOC(i) =N+ΣiAll subclasses NOC(i)

Where N is the total number of immediate subclasses of class i.

Coupling between object classes (CBO):

Coupling between Object Classes (CBO) is a count of the number of other classes to which a

class is coupled. Excessive coupling is detrimental to modular design and prevents reuse. The

more independent a class is, the easier it is reuse in another application. The larger the number of

couples, the higher the sensitivity to changes in other parts of the design and therefore

maintenance is more difficult. Strong coupling complicates a system since a class is harder to

understand, change or correct by itself if it is interrelated with other classes.

Response for a class (RFC):

According to this metric “Coupling between Object Classes” (CBO) for a class is a count of the

number of other classes to which it is coupled. Theoretical basis of CBO relates to the notion that

an object is coupled to another object if one of them acts on the other, i.e. methods of one object

use methods or instance variables of another. Here we are restricting the unidirectional use of



methods or instance variables of another object by the object of the class whose reusability is to

be measured. As Coupling between Object classes increases, reusability decreases and it becomes

harder to modify and test the software system. So there is the need to set some maximum value

of coupling level for its reusability. If the value of CBO for a class is beyond that maximum

value then the class is said to be non-reusable. It is the number of methods that can be triggered

by a message sent to an object.

Software Testability:

Software testability is affected by many different factors, including the required validity, the

process and tools used and the representation of the requirements. Voas et. al. [27] defines

software testability as the probability that a piece of software will fail on its next execution

during testing, provided it contains a fault. This fault sensitivity is obtained by multiplying the

probabilities that

(1) the location containing the fault is executed;

(2) the fault corrupts the program’s state; and

(3) the corrupted state gets propagated to the output.

High fault sensitivity indicates high testability and vice versa. The effort required to test a

program to ensure that it performs its intended function. Thus testability is also measured in form

of testability effort. The effect of values of CK metrics on testability is defined in the principles

below:

Principles for measuring Testability are:

1. LOC, the larger the size of a class, more effort is required to test a class.

2. WMC, more the methods in a class, more difficult it is to test the class.

3. DIT, greater is the inheritance tree, more testing effort is required.

4. NOC, more no. of children more will be the testing effort.

5. CA, increased complexity will increase testability of the software.



Based upon these principles (1 – 5), equations for measuring testability are following:

Testability of a class = a*(LOC) + b*(WMC) + c*(DIT) +d*(NOC) +e*(CA)

where a, b, c, d, e are regression coefficients.

a =b =c = d =e = 1

Testability of OO program = sum (testability (class)i)

where i = 1 to n, n is number of classes.

3. COLLECTION OF METRIC DATA

To collect metric data, we have used Eclipse platform. Source code is given as input to the

Metrics tool. We analyzed software testability on metric.java and calculate ck metrics. Eclipse

Metrics tool is an open source tool which is available on internet.

Fig 1: Metric.java



Fig 2: QualityFactorGenerator.java

4. METRIC VIEW:

To view metrics of source program, we have to enable metrics view from the menu list. It will

display the object oriented metrics for the code.

Fig 3:Metric view



Metric Metric.java QualityFactorGenerator.java

NOC 0 0

CA 1 1

TLOC 108 40

LCOM 1 0

WMC 27 3

Table 1: CK metrics

Fig 4: Metric graph

These metrics are saved as a text file and given as input to the QualityFactorGenerator which

further calculates software testability.

Fig 5: Input File

0

20

40

60

80

100

120

NOC CA TLOC LCOMWMC

metric.java

QualityFactorGenerator.java



Fig 6: Software Testability

5. CONCLUSION:

The framework proposed in the paper will address testability during software development life

cycle. It may help putting testability benchmarking of software projects. The framework is

generic in nature, and may be used by industry practitioners to quantify testability in order to

make design decisions early in the development life cycle. In future, we have to emphasize on

more testability characteristics. We will introduce more software metrics too calculate testability

accurately.

6. REFERENCES:

[1]R. A. Khan, K. Mustafa, I Ahson, “An Empirical Validation of Object Oriented Design

Quality Metrics, Journal King Saud University, Computer & Information Science, Vol. 19, pp.

1-16, Riyadh (1427H/2007).

[2] Jungmayr, S. Testability Measurement and Software Dependencies. In Proceedings of the

12th International

Workshop on Software Measurement, pp. 179–202, October 2002.

[3]Bertolino, A., and Strigini, L., “On the Use of Testability Measures for Dependability

Assessment”, IEEE Transactions on Software Engineering, VOL. 22, NO. 2, February 1996.

[4] McCall, J. A., Richards, P. K., and Walters, G. F., “Factors in Software Quality”, Nat’l Tech.

Information Service, no. Vol. 1, 2 and 3, 1977.

[5]Booch, G., Object Oriented Design with Applications. Redwood City, CA: Benjamin/

Cummings, 1991.

[6]P. Coad and E. Yourdon, Object-Oriented Design. Englewood Cliffs, NJ: Prentice-Hall, 1991.



[7]Magiel Bruntink, Arie van Deursen, “Predicting Class Testability using Object-Oriented

Metrics” Proceedings of the Fourth IEEE International Workshop on Source Code Analysis and

Manipulation (SCAM’04), pp 1-10, 2004


International Journal of Engineering and Social Science

www.gjmr.org 10

INDIAN REAL ESTATE- A BOON TO THE ECONOMY

Dr. V. Santhi*

Benon.S**

Arun Kumar.J**

ABSTRACT

The prospects for real estate industry in India goes buoyant. All the factors that contributed to the

growth of real estate sector- high disposable incomes, sharp increase in global liquidity, selective

capital account liberalization, looser credit policies, a greater availability for the leverage due to

financial liberalization and the consequent increase in shortage lending and price increase.

*Asst.prof(S.G), Dept of Humanities, PSG College of technology, Coimbatore-641004

** III B.E (SW) EEE , PSG College of technology, Coimbatore-641004



www.gjmr.org 11

INTRODUCTION

Real estate sector in India is witnessing tremendous boom and is presently worth $12 billion and is

growing at the rate of 30 per cent per annum.It is the second largest employer next to

agriculture.India is fast evolving in the real estate market witnessing a growth in construction

activities both in residential as well as commercial and retail segments. It has observed that the real

estate action is no longer limited to the large metropolises of India but has now permeated to the

burgeoning smaller towns and cities. These emerging centers of growth are lending sparkle to India's

booming economy. It has emerged as the most profitable business venture to invest US $ 90 billion

by 2015 also witnessing huge FDI (Foreign Direct Investment), not only due to the 100 per cent

Government allowance with fast track approvals but also due to high potential investment returns of

more than 25-30 per cent. Eighty per cent share of the real estate market is garnered by residential

sector and the rest is comprised of offices, shopping malls, hotels and hospitals.One Rupee invested

in real estate sector results in 78 paise being added to the GDP of the country.With the urban

population of India is likely to grow from 285.3 million in 2001 to 360 million in 2010, 410 million

in 2015, 468 million in 2020 and 533 million in 2025 gives a huge potential simultaneously demand

for affordable residents which is considered as the basic need of human being of food, water and

shelter. The current size of real estate construction industry in India is estimated to be approximately

US$44 billion. The boom in retail industry has also spurred the growth in real estate sector. India at

the moment is witnessing a spurt in extremely large retail spaces.The industry is highly fragmented.

The top 10 players account for approximately 10 per cent of the total revenue of the industry, while a

major part is attributed to unorganized real estate contractors.The industry is expected to witness an

annual average growth rate of approximately 26 per cent till 2014. The main focus area of almost all

real estate companies is the ‘affordable housing,’ which controls more than 50 per cent of residential

sales in key residential areas such as Chennai, Gurgaon and Mumbai.The prevailing stature of the real

estate market in India and it growth statistics motivated us to carry this introspective study. Real

estate construction industry is also getting benefited from government initiatives. The Government of

India, in order to attract foreign direct investment in the industry, is working out on easier rules for

overseas investors to invest in smaller real estate projects.



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NEED FOR THE STUDY

Low interest rates, modern attitudes to home ownership (the average age of a new homeowner is now

32 years compared with 45 years a decade ago), economic prosperity along with a change of attitude

amongst the young working population from that of ‘save and buy’ to ‘buy and repay’ and liberalized

FDI regime have all contributed to sector in this boom. The above stated definition has created a need

for framing the below mentioned objective of the study to analyse the consumers preference for

towards the modern town ship development, their simultaneous perception and motivating factors at

micro level.

OBJECTIVES OF THE STUDY

To analyze the level of perception of consumers towards the Township Project.

To state the factors influencing the purchase of Villas in Township project.

To offer suggestion for Taamaesek Engineering Consortium India and S.P.Apparels in

promoting the Township.

SCOPE FOR THE STUDY

This study provides scope to review the pattern of consumer’s attitude towards the modern township

development proposal at Tirupur and Coimbatore Districts and also draw an introspective view of the

property promoters’ perception about the same. Thus it supposed that the current study to

demonstrate functional issues of real estate business development to research scholars, academician,

economic planners and the marketers as a whole.

INTRODUCTION TO THE COMPANY

The current study is based on the real-time project proposal joint-venture signed between the

Taamaesek Engineering Consortium India and SP Apparels to develop a modern town-ship.

Taamaesek Engineering Consortium India established in the year 2000,having worked on many

prestigious projects in Singapore, viz Fullerton Hotels, Ritz Carlton, Hazel Park & Flora Vale

condominiums, Millennia towers & Centennial towers etc., is ably assisted by a core team of 20



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engineers with various levels of International work execution and project management expertise and

100 engineering professionals from all streams of engineering contributing to a value engineered

design. Drawing on the multi - disciplinary expertise, generates a value engineered design to create

maximum value and enhance quality of life is the MISSION and VISION of the organization.

Taamaesek Engineering Consortium India’s total involvement and comprehensive value engineering,

in every project cutting across all services such as civil, structure, trades, electrical, air conditioning,

plumbing, fire detection and suppression, networking, water treatment, interiors. The Major

competitors for the concern are; JLL, CBRE and CUSMAN.

SPAL, well known Knitwear Garment manufacturer is in the business for nearly two decades. SPAL

is one of the largest Knitwear Exporter in India and is ranked second among 5000 Exporters in

Knitwear town of Tirupur, South India. SPAL is focused on producing extensive range of Knit

Garments viz. Kids wear – 50per cent, Ladies Garments -35per cent & Men’s wear-15per cent. SPAL

is catering to major global brands and chain stores. The unit has set up globally acceptable standards

and quality norms. With this expertise gained in the manufacturing,SPAL plans to build domestic

brand in order cash in vibrant and expending domestic garment market. SPAL holds 70 per cent

equity stake in Crocodile Products Private Limited in. The Joint Venture Partner being Crocodile

International Private Limited, Singapore. Further it is proposed to commence more stores all over the

country. The Company has vertically integrated manufacturing set up starting from Spinning,

Knitting, Processing (Dyeing), Printing & Embroidery, Sewing Facility and Retail in domestic

market.To be the best clothing supplier in the world aggressively work into US, & other EU

Countries and increase the customer base by 25 per cent a year, to grow into a 2000 cr. Company by

2015 and to create a retail presence pan India within one year is the MISSION and VISION of the

organization.

RESEARCH METHODOLOGY

Real estate property development joint venture named “OPULENCE” has been signed between

Taamaesek Engineering Consortium India and SP apparels to build a modern town ship. A marketing

research has been conducted on their request to know the feasibility of developing a town ship

connected directly by the NH 49 National High Way Road Line. The data was collected through a



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well structured interview schedule. The chi-square test is an important test amongst the several tests

of significance.It is a statistical measure used in the context of sampling analysis for comparing a

variable to a theoretical variance. As a non-parametric test, it can be used to determine if categorical

data shows dependency or the two classifications are independent. The entire hypothesis test in this

study was carried out at 5 per cent level of significance.An attempt was made to analyze the main

factors influencing the level of buyer preference with the evident of the selected sample respondents

in the study area. For the purpose of the detailed analysis, variable are classified in two important

strata which are termed as dependent variables and independent variables. The buyer preference

interms of opinion towards likeliness, opinion towards uniqueness and opinion towards willingness

by the sample respondent was taken as dependent variables and the independent variables used in

this study are age, location, annual family income. The instrument used in collecting the primary data

was Structured Questionnaire. The questionnaire consisted of both closed and open ended questions.

The sample size taken for my study is about 200 respondents. Area sampling was done. If cluster

happen to be some geographic subdivisions, cluster sampling is better known as area sampling. In

other words, cluster designs, where the primary sampling unit represents a cluster of unit based on

geographic area, are distinguished as area samplings. The frequency distribution of the variables were

calculated with help of simple percentage, by writing the formula FD = F/N x 100. Where F denotes

the number of respondents, and N denotes the total number of sample population.

Chi–square test (2) = E

EO 2)(

Degrees of freedom = (R-1) (C-1)

Where O = observed frequency

E = expected frequency

R = number of rows

C = number of columns



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The 2 values obtained as such should be compared with relevant table value of 2 and the inference

can be drawn. If the calculated value is greater than the table value the hypothesis framed will be

rejected, otherwise accepted.

TABLE-I

FACTORS INFLUENCING THE BUYERS DECISION

S.NO FACTORS TOTAL

SCORE RANK

1. Price 1640 1

2. Location 1404 2

3. Transport, Shops and Public

Amenities 1040 3

4. Facilities & Amenities 798 4

5. Brand Image of builder / property

developer 530 6

6. Landscape Area (Sq.Ft) 48 10

7. License of the Builder 368 7

8 Registration & Documents 240 8

9. Loans & EMI 660 5

10. Security of the Property 112 9

Source-primary data

It is found from the analysis that most of the respondents are influenced by competitive price, locality

and transport, shops and public amenities.



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FIGURE-I

AGE AND FACTOR SCORE

FIGURE-II

AGE AND FACTOR RANKING



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FIGURE-III

GENDER AND FACTOR SCORE

FIGURE-IV

GENDER AND FACTOR RANKING

FIGURE-V



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ANNUAL INCOME AND FACTOR PRICE

FIGURE-VI

ANNUAL INCOME AND FACTOR RANKING



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FACTORS INFLUENCING TO BUY TOWNSHIP

The following variables have been selected to the level of likeliness; uniqueness and willingness to

purchase the property are Age, Location, Annual family income and Profession.

TABLE-II

AGE AND OPINION ABOUT WILLINGNESS TO BUY A TOWNSHIP

Age

(in yrs)

Opinion towards willingness

Total Definitely

would buy

Probably

would buy

Might

or

might

not buy

Probably

would not

buy

Definitely

would not

buy

20 – 30 16

(44.4)

6

(16.7)

4

(11.1)

0

(0)

10

(27.8) 36

30 – 40 16

(24.2)

22

(33.3)

20

(30.3)

4

(6.1)

4

(6.1) 66

40 – 50 8

(12.1)

32

(48.5)

8

(12.1)

4

(6.1)

14

(21.2) 66

Above 50 4

(12.5)

16

(50)

4

(12.5)

0

(0)

8

(25) 32

Total 44 76 36 8 36 200

SOURCE-PRIMARY DATA



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TABLE-III

CHI-SQUARE TEST

Factor Calculated 2

Value

Table

Value D.F Result

Age 28.750 21.026 12 Rejected

The above table shows that the calculated chi-square value (28.750) is greater than the table value

(21.026). So, the null hypothesis is rejected. Hence, there is a close significant relationship between

age and opinion about willingness to buy a township.

TABLE-IV

ANNUAL FAMILY INCOME AND OPINION ABOUT WILLINGNESS TO BUY A

TOWNSHIP

Annual Family

Income


Total

Score Definitely Probably Might or

Might not

Probably

not

Definitely

not

Less than

2,00,000

2

(25)

2

(25)

0

(0)

2

(25)

2

(25) 8

2,00,001 –

4, 00, 000

2

(20)

0

(0)

4

(40)

2

(20)

2

(20) 10

4,00,001 –

6,00,000

4

(18.2)

16

(72.7)

2

(9.1)

0

(0)

0

(0) 22

6,00,001 – 10 18 8 0 0 36



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8,00,000 (27.8) (50) (22.2) (0) (0)

8,00,001 –

10,00,000

10

(22.7)

16

(36.4)

6

(13.6)

2

(4.6)

10

(22.7) 44

Above 10,00,000 16

(20)

24

(30)

16

(20)

2

(2.5)

22

(27.5) 80

Total 44 76 36 8 36 200

SOURCE-PRIMARY DATA

TABLE-V

CHI-SQUARE TEST

Factor Calculated 2

Value

Table

Value D.F Result

Annual

family

income

54.138 31.410 20 Rejected



annual family income and opinion about willingness to buy a township.



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TABLE-VI

LOCATION AND OPINION ABOUT WILLINGNESS TO BUY A TOWNSHIP

Location


Total Definitely Probably

Might or

Might not

Probably

not

Definitely

not

Coimbatore 12

(12)

46

(46)

12

(12)

6

(6)

24

(24) 100

Tirupur 32

(32)

30

(30)

24

(24)

2

(2)

12

(12) 100

Total 44 76 36 8 36 200

SOURCE-PRIMARY DATA

TABLE-VII

CHI-SQUARE TEST

Factor Calculated 2

Value

Table

Value D.F Result

Location 13.368 9.488 4 Rejected



location and opinion about willingness to buy township



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TABLE-VIII

PROFESSION AND OPINION ABOUT WILLINGNESS

TO BUY A TOWNSHIP

Profession



Might or

Might not

Probably

not

Definitely

not

Business /

Industrialist

18

(22.5)

32

(40)

16

(20)

2

(2.5)

12

(15) 80

Self Employee 16

(26.67)

24

(40)

8

(13.33)

2

(3.33)

10

(16.67) 60

Employee 10

(16.67)

20

(33.33)

12

(20)

4

(6.67)

14

(23.33) 60

Total 44 76 36 8 36 200

SOURCE-PRIMARY DATA

TABLE-IX

CHI-SQUARE TEST

Factor Calculated 2

Value

Table

Value D.F Result

Profession 5.898 15.507 8 Accepted



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The above table shows that the calculated chi-square value (5.898) is less than the table value

(15.507). So, the null hypothesis is accepted. Hence, there is no significant relationship between

profession and opinion about willingness to buy a township.

TABLE-X

PROFESSION AND OPINION ABOUT WILLINGNESS

TO BUY A TOWNSHIP

Profession



Might or

Might not

Probably

not

Definitely

not

Business /

Industrialist

18

(22.5)

32

(40)

16

(20)

2

(2.5)

12

(15) 80

Self Employee 16

(26.67)

24

(40)

8

(13.33)

2

(3.33)

10

(16.67) 60

Employee 10

(16.67)

20

(33.33)

12

(20)

4

(6.67)

14

(23.33) 60

Total 44 76 36 8 36 200



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TABLE-XI

CHI-SQUARE TEST

Factor Calculated 2

Value

Table

Value D.F Result

Profession 5.898 15.507 8 Accepted

The above table shows that the calculated chi-square value (5.898) is less than the table value

(15.507). So, the null hypothesis is accepted. Hence, there is no significant relationship between

profession and opinion about willingness to buy a township.

FINDINGS

Price got the first rank in all categories of gender and landscape area got the tenth rank in all

categories of gender.

It brings from the analysis that majority of the respondents are very much interested to buy a

township.

Most of the respondents are influenced to buy a township by its competitive price, locality and

transport, shops and public amenities.

While in the case of Annual family income level, the respondents who earn eight lakhs to ten

lakhs opined that they are willing to purchase township. The result of chi-squared test

accepted the result at 5 per cent level of significance.

It is clear from the analysis that the respondents who are businessman and self employees are

opined that they probably would buy the township than the other group of the respondents.

RECOMMENDATION

The current study aims on the consumer’s attitude on purchase of opulence township, so as to take

informed business decisions (which would form as inputs to go ahead with the proposed township)

and through this process of study it has been found that India’s real estate market is poised for

tremendous growth potential with a wave of development and investment into these “exciting”



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assets. It is recommended that the “Opulence” has been well received by the industry stakeholders

company and they can go forward with the project. Opulence can be further added to the project

proposal green property with infrastructure, keeping tradition & technology under one roof .It is also

recommended that the concern can added amenities which can provide Yoga / meditation centers,

Gym, Clinics, Crèche, ATMs etc., Developers can look at Coimbatore - Tirupur belt for the further

business promotions.The price tag should be moderately range between 30 – 40 lakhs to attract all

categories of potential buyers.

CONCLUSION

It was observed that the main factor affecting the real estate business in Coimbatore and Tirupur

districts is due to the increased in land prices, followed by government policies / lack of infrastructure

and lastly by fluctuation in interest rate in home loans.India is emerging as one of the places to live

in with tranquility and a better social life. India now is not only a place to find greenery and an

enriched culture but also it is the place to find various opportunities in terms of jobs and money. Due

to growth in income class there has been an unprecedented rise in the real estate business in India.

. Real Estate Agents are good option as well, for those service class people who hardly have enough

time to search for place to put up their effects. There is a discernible hunger for knowledge and

interaction as developers and investors begin to penetrate the Indian real estate market. The

Opulence’s key success lies in the provision of pollution free environment, hassle free traffic,

optimum utilization of the scope of upcoming projects proposed area, existing educational

establishments (for multiplex/malls) and location proximity etc.,

References:

Books-

1. C.R.Kothari- Research methodology and techniques, second edition, new age international (p)

Limited publications, Reprinted, 2005.

2. O.R. Krishnaswamy and M.Ranganatham- Methodology of Research in social science;

Himalaya Publishing House; reprint 2006.



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3. Philip Kotler, “Marketing Management”, prentice hall of India private Ltd., New Delhi, 2000.

4. Pillai,R.S.N and Bagavathi, “Modern Marketing”, S.Chand and Company Ltd., 2004

Journals and Magazines-

1. Rands Joseph, Real Estate Development in India; Published 10/07/2006

2. Samuel Zell, Real estate industry- The true barometer for a country’s economy; Keynote

Address, Chairman Equity Group Investments, USA in a International Symposium; a Global

Platform where Developers & Investors Gather to Discuss Emerging Opportunities in India

Real Estate Market; 23-25 April 2007, Renaissance Mumbai Hotel & Convention Centre,

Mumbai, India.

3. Jones Lang LaSalle Meghraj (2007); Emerging Trends and Adoption of Sustainable practices

in India; New Delhi, 25 November.

Web Sites-

1. http://www.buzzle.com/articles/real-estate-developements-india.html

2. Mizra Sajid; Properties in south India; Article sphere; May 2007. :

http://www.articlesphere.com/Article /Properties-in-south-India/156562.



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WIRELESS SIGNAL STRENGTH ENHANCEMENT IN LOCAL AREA NETWORK (WLAN)

M. Umair Saleem*

Tasleem Mustafa**

Ahsan Raza Sattar***

Dr. Muhammad Saleem****

Dr. Shaukat Ali*****

ABSTRACT

With the improvement in IEEE 802.11 standards, wireless networks are increasing in number.

With the advancement of technology, the data rates and coverage of Wi-Fi and usage for

different high bandwidth increases. The major problem in the Wireless Local Area network

(WLAN) is its coverage. In this research, different techniques were implemented to increase the

signal strength of wireless network (WLAN). Various forms of antennas (circular, parabolic etc.)

with different types of material (aluminum, steel and iron etc) were prepared locally. These

devices were used to increase the signal strength of WLAN in a minimum cost. These equipments

were attached with the AP (Access point) to enhance its efficiency and signal strength.

Furthermore comparative study among these devices with AP and existing devices were carried

out to evaluate the performance of above mentioned antennas.

*Computer Network Engineer, MIT College of Commerce and Computer, Faisalabad, Pakistan.

** Chairman, Department of Computer Science, University of Agriculture Faisalabad, Pakistan.

*** Lecturer, Department of Computer Science, University of Agriculture Faisalabad, Pakistan

**** Senior Research officer, Dept. of water management, University of agriculture Faisalabad, Pakistan.

***** Assistant Professor, University of Agriculture Faisalabad, Pakistan



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INTRODUCTION

In the present, the industry is grown towards portability of network. Most of the phone

companies and signal based network companies launch wireless network facilities instead of

wired network. This mobility supports efficiency as well as service opportunities not achievable

with wired networks.

NEED FOR RESEARCH

In wireless network, the communication of network is based on signals. If everything is alright

then the user (who is wirelessly connected with the network) is using network by sitting at a far

distance, he must has a network coverage problem. But how the network increases its signals and

covers a long distance in a minimum cost. When the signal drops then the speed of the network

access will automatically decrease. Hence the signal must be strong and covers long distance

with networks original speed. The major problem in the Wireless Local Area Network (WLAN)

is its coverage. But it is possible to increase signals with the use different types of antennas. But

these are much costly antenna devices. Small CPW-fed T-shaped antenna for MIMO application

was presented to gain signal strength of wireless network. The size of the antenna was only 35%

of conventional CPW-fed T-shaped antenna, which had been satisfied return loss bandwidth and

Omni-directional radiation characteristics. Wi-Fi Access Points are being configured in most of

the possible areas like public parks, hotels, banks and universities.

ANTENNA CHARACTERISTICS

The D-Link Extreme Antenna was a multipurpose antenna designed to help get better

performance of wireless signals. It was an Omni-directional antenna (360o coverage) with the

range of 200 meters shown in figure (1). The dimensions of this antenna was (2.9” x 4.2” x 5.3”).

Operating Temperature of the antenna was (-3°F to 150°F (-21°C to 66°C)) and Storage

Temperature was (-21°F to 170°F (-29°C to 80°C)) it was so much expensive antenna as

compared to signal strength. The market price of this antenna was 180$.



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Figure (1): D-Link Extreme N™ 2.4GHz Antenna

WIRELESS SIGNAL RADIATION OF D-LINK EXTREME ANTENNA IN

AIR:

The above antenna spreads the wireless signals in a circular form shown in figure (2). It radiates

the signals up and down like a jumping ball.

Figure (2): Wireless signal radiation of D-Link Extreme antenna

MATERIAL USED TO BUILD D-LINK EXTREME ANTENNA:

The first step in building of wireless antenna is the collection of the material required for

building. The essential materials for the wireless antenna are as follows.

1. Low resistance aluminum wire



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2. Special plastic for coating

3. Special nut to connect with Access Point

4. Aluminum connectors

5. Ninety degree straight building of antenna

6. Fine soldering

7. Low resistance Copper wire

In this research, different techniques and types of antennas were judged-in for the investigation

to increase the signal strength and spread signals of wireless network. Various forms of antennas

(Omni-directional) with different types of material (aluminum, steel iron etc) were prepared

indigenously.

These devices were used to increase the signal strength of WLAN in a minimum cost. The total

cost of these type of antennas was approximately 3$ to 5$. These equipments were attached with

the AP (Access point) built in antenna to enhance its efficiency. The range of these antennas was

approximately above 1000 meters (1km) in outdoor use. Furthermore comparative study among

these devices with AP and existing devices was carried out to evaluate the performance of above

mentioned antennas.

PROBLEM STATEMENT:

In a wireless based network, signal range is a big problem. A user who wants to connect with a

wireless network from a far distance must have a signal problem. When the signal drops then the

speed of the network access will automatically decrease. The user cannot make a reliable

connection with the network. A 5-dbi Access Point antenna has no enough signal strength. The

maximum outdoor range of that antenna was 100 meter. In this research, we investigated new

home made antenna to increase signal strength of Wireless Network.

PROPOSED SOLUTION:



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A new home made wireless antenna was investigated to increase signal strength. This antenna

was used to increase signals up-to 1000 meters and also in a minimum cost. Following are the

specification of homemade antenna.

Wireless signal radiation of homemade wifi antenna in air:

The following figure (3) shows that the signal spread in the air horizontally. The signal strength

level was not same in all the directions. It depends on the environment and other factors i.e.

building, furniture and trees etc. It spreads signals at least 1 km.

a. Horizontal View

Figure (3): Wireless signal radiation of homemade wifi antenna

b. Vertical View

The following figure (4) shows, how the signal spread in the air. The vertically view of signals

shows that the signals are spreading like a fountain. The signal strength level is not same in all

the sides. Middle lobe is approximately 300 meter up in the air and side lobes covers 1000 meter

approximately in left and right. The signal strength depends on the environment and some other

factors i.e. building, furniture and trees etc. But with all these factors this antenna spreads signals

at least 1 kilo meter.



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Figure (4): Wireless signal radiation of homemade wifi antenna

Material to build Homemade antenna.

The first step in building the wireless home antenna is the collection of the material required for

building. The essential materials for the homemade wireless antenna are as follows

1. Local packing aluminum foil

2. Local Copper wire

3. Aluminum wire

4. Nuts and Bolts

ADVANTAGES

RANGE as compared to other antennas:

The range of any antenna depends on the material of antenna and also the environment in which

that antenna is used. This antenna was made up of a local material like aluminum, iron and steel.

The range of this antenna was more than 1000 meters (1 km).

The user can connect with the network easily while he will away from the access point up to

1000 meter. The efficiency of this antenna is very high than the other wireless antennas.

OUTDOOR Adjustment:

The antenna should be placed outdoor approximately 20 feet high from the ground.

Material used



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A local material was used to build homemade antenna. A simple rough aluminum and plane steel

was required to build this antenna.

PRICE compared to the other antennas:

The price will depended on the material which is used to manufacturing of antenna. This

research also concluded that these antennas were made up of a local aluminum and iron material.

The Total cost to build this antenna was approximately 3$-5$. It was most reasonable price

antenna.

Research Methodology

The major problem of WLAN network is the network coverage range. When the signal drops

then the speed of the network access will automatically decrease. The requirements, was to

increase the network signal strength also in a minimum cost. In this research, we were

investigated new techniques to increase signal strength of WLAN. Various forms of antennas

with different types of materials i.e Aluminum and iron etc was prepared locally. These devices

were used to increase the signal strength of WLAN and in a minimum cost. These antennas were

attached with the AP (Access point) antenna to enhance its efficiency. The signals which were

emits from the AP were reflected by these antennas and travels a long distance as compared to

the AP.

Materials and Methods

Wireless Networks are spreading day by day due to their reliability, ease and low cost. The speed

and the reliability of communication of communicating devices is depends on wireless signal.

These signals must be strong, powerful and covered long distance as possible in a minimum cost.

These are strong if the user is using network in its coverage range. The aim of this research was

investigated that how to improve the signal strength of Wireless Local Area Network (WLAN)

and new ways of improving existing standards in terms of distance covered and data rates.

There are lot of software available in the market to measure the strength once the access point

has been installed (Net Stumbler, 2007) or to even plot-out maps of signal strength (Air Magnet,

2007); however to gain this information in proceed of the installation requires a degree of

calculation. This is particularly important in business environments, where it is necessary to

know that network connection cannot be made to the network from outside the building.



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Figure 5: Wireless signals in building

Some security point of views was also a big question that It is necessary to guarantee that the

user cannot be connect to the network if he wants to connect to the network from outside of the

building. If his device full strength signals then he can easily connected to the network. Figure 5

shows an example of the results of a survey, which is color-coded to aid the explanation of the

information.

Increasing Signal Strength with Homemade Antenna

A homemade antenna was attached with the Access point to increase its efficiency. When the

user was out of range from the access point range, low speed of 5.5 Mbps shown in Figure (6). It

cannot connect a reliable connection, and have no access of network with the proper speed.

Figure 6: Wireless network out of range



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A homemade antenna was attached with the Access point, that antenna was gain the signal

strength up to double of signals original coverage of access point. A user who was received 5.5

Mbps signals with original antenna of AP, was received 54 Mbps speed with the home made

local antenna shown in the figure (7).

Watch out the speed: 5.5 Mbps

Watch out the signal strength level: 3 of 5 lights are glowed.

Signal quality was also very low. Hence the sent and receive capability would also be

decrease due to low signals.

Figure (7): Wireless network increase high range

Signal Measurement Calculator:

PdBm = Log Pmw x 10

1 Watt = 1x 1000 mW

PdBm = Log 1000 x 10 = 30 dBm

100 mW; P dBm = Log 100 x 10 = 20 dBm

For link budget calculations, the dBm convention is more convenient than the Watts convention.



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Signal Attenuation

Attenuation (fading) of an RF signal is defined as follows:

Pin : power level input at the attenuator input

Pout: power level output at the attenuator output

Attenuation is expressed in dB as follows: PdB = 10 x Log (Pout / Pin)

i.e., If, due to attenuation, 1/2 power is lost (Pout/Pin = 2),

Attenuation in dB is 10 x Log (2) = 3dB

Path Loss

Path loss is the loss of power of an RF signal travelling (propagating) through space. It is

expressed in dB. Path loss depends on:

Antenna height is a great factor of path loss.

Line of sight clearance between the receiving and transmitting antennas.

The distance between receiving and transmitting antennas.

Loss of Free Space

Attenuation of the electromagnetic wave while propagating through space. This attenuation is

Calculated using the following formula:

Loss of Free space = 20 * Log R (Km) + 20 * Log F (MHz) + 32.4

F = RF frequency expressed in MHz.

R = distance b/t the receiving and transmitting antennas.

At 2.4 Ghz, this formula is: 20 * Log R (Km) + 100

THE EXPERIMENTS

In total, three experiments were performed. The following are the experiments.

Experiment 1st Sniffing for sources of the interference

While performing all experiments, other 802.11 wireless equipments can potentially affect any

results obtained. Thus, the aim of the experiment had been identified, ' II" I I other potential

802.11 causes of the interference using a wireless sniffer. A wireless sniffer was a program that

has ability to capture and report to the user all traffic in the form of the packets (including beacon

frames) that traverses in free space. Wireless on had been a tool that allows users to monitor the

status of the wireless adapter(s) and gather information about nearby wireless access points in

real-time, it can help users to:



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The measure of the network throughput and view available data rates

Verifying the their network configuration had been correct

Experiment 2nd: The Time Variance

The correct variance over the time of the signal power and Packet mistake Rate had been

unknown. This testing aims to settle on if the signal power and ultimately the error rates alter

considerably over time. We had been chosen any measurement point relatively close to the AP

(ensure packets will be conventional by the wireless swarm) and run the program for as long as

possible.

Experiment 3rd: Signal propagation

The main aim of this experiment had been to determine the signal strength and the amount of the

loss throughout in the area. All of this area had been measured in which experiment had to be

conducted. The plan captured the emit packets from the AP side and record data to the TXT and

database files.

Uploading the data

Once the experiments had been completed during allocated slot, the collected data from all above

three experiments has been then uploaded using a wired connection to a desktop system. The

files that are uploaded include

Text files

Wireless Mon files

Signal strength files

Data Analysis

The statistically software had been needed to that analyzed the experimental results of the

experiment and proceeded to collate the recorded data within the text and database files into

meaningful and compact information set. The program outputs of this information on a single

line along with the particular area. The information set had been present in the database a file

determines. The round trip time i.e. time in which packet send and received had been to the

system at a particular distance and at a particular packet size, the average signal strength had

been the total number of the packets collected and finally the number of the packets was missed.

REUSLTS AND DISCUSSION

It was studied the motivation by the need for fundamental understanding of ultimate limits of

bandwidth efficient delivery of higher bitrates in digital wireless communications and to also



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begin to look into how these limits might be approached. He examined that exploitation of multi

element array (MEA) technology that was processing the spatial dimension (not just the time

dimension) to improve wireless signal strength and capacities in certain applications.

Measuring and Performance signal strength:

Access point was sending Normal signals, and Pc was received average signals before

implemented homemade (Locally) metallic material antenna behind Access point shown in the

figure 18.

Figure (8) signal strength

Access point was sending High signals and Pc receives high signals after implementing

homemade (Locally) antenna behind Access point shown in the figure 8.



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Figure (9): Boost signal strength

Analysis of reason of Signal loss

The requirements, is to increase the network signal strength also in a minimum cost. In this

research, we were investigated new techniques to increase signal strength of WLAN. Various

forms of antennas with different types of materials i.e. Aluminum and iron etc was prepared

locally. These devices were used to increase the signal strength of WLAN in a minimum cost.

These antennas were attached with the AP (Access point) antenna to enhance its efficiency. The

signals which were emitting from the AP were reflected by these antennas and travel a long

distance as compared to the AP.

Distance Vs Mean

020406080

100120140160180200

0 50 100 150 200 250

Mean

Dis

tan

ce

Mean

Figure 10: Distance Vs Mean RTT

The above figure 10 shows that the distance VS mean. The distance increase and distance

decrease was affected negatively on the network. The distance of 90 feet and 110 feet was

significant effect. The distance of 170 feet has the mean of 140

Byte Vs Mean RTT

0

20

40

60

80

100

120

140

160

0 10000 20000 30000 40000 50000 60000 70000

Byte

Mea

n

Mean

Figure 11: Byte Vs Mean RTT



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The above figure 11 shows that the bytes vs. mean RTT. 5000 bytes have the mean of 16.95,

15000 have the mean of 41.62, 25000 have the mean of 65.45, 35000 have the mean of 74.616,

45000 have the mean of 92.977, 55000 have the mean of 120.598, 65000 have the mean of

139.697.

Effect of walls vs. Packet Loss

The above table shows the %age packet loss which shows that as we increase the number of

walls packet loss increases but there is another consideration that if the size of packet is small

there is almost no loss in case of six walls even so we conclude that if the packet size is small the

loss will be almost nil and if we want to communicate from such a location we must maneuver

packet size.

Effect of number of floors vs. RTT

We conducted experiment in university administration block to check the effect of %age packet

loss and increase in RTT in multi-Floor building. We designed a scenario in which first we

placed AP at 3rd Floor and PC on second, first and ground respectively. Than we place AP on

2nd floor and PC on first and first and ground Floor, the last part of the experiment was to place

AP at 1st floor and PC at ground floor. The analysis of variance table is below:

SUMMARY

Main aim of my research had been to look in the current technologies influencing the market like

“wireless local area networks” due to the cheap cost and efficiency, how were the Access Point

sends the signals, how were the antenna boost the signals. In wireless network, the

communication of network is based on signals. If everything is alright then the user (who is

wirelessly connected with the network) is using network by sitting at a far distance, he must has

a network coverage problem. But how the network increases its signals and covers a long

distance in a minimum cost. When the signal drops then the speed of the network access will

automatically decrease. Hence the signal must be strong and covers long distance with networks

original speed. The major problem in the Wireless Local Area Network (WLAN) is its coverage.

But it is possible to increase signals with the use different types of antennas. But these are much

costly antenna devices.

In this research, we have been investigated new techniques to increase signal strength of WLAN.

Various forms of antennas with different types of materials i.e. Aluminum and iron etc have been



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42

prepared locally. These devices were used to increase the signal strength of WLAN in a

minimum cost. This antenna was attached with the AP (Access point) antenna to enhance its

efficiency. The signals which were emitted from the AP will amplified with these antennas and

travel a long distance as compared to the original signals of AP. Furthermore comparative study

among these devices with AP and existing devices will be carried out to evaluate the

performance of above mentioned antennas.

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for propagation prediction for indoor wireless communications. IEEE Antennas and Propagation

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slot antenna. Progress In Electromagnetics Research, 7(6): 237-242.

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using ordinary kriging, Proceedings of the Winter Simulation Conference, 9(8): 2888-2896.

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SECURITY IN VEHICULAR AD-HOC NETWORKS - CHALLENGES

AND COUNTERMEASURES

Ann Baby*

.Dr.Sreekumar**

ABSTRACT

Vehicular Ad-hoc Networks (VANETS) are a kind of MANETs (Mobile Ad Hoc Networks) which

operate without any predefined infrastructure. Vehicular Networks are conceived from the

Intelligent Transportation Systems. Ad hoc (or self-organizing) networks operate without

predefined infrastructure. In VANETs, vehicles equipped with Wi-Fi hardware constitute the

mobile nodes (hosts). VANETs help in inter vehicular and intra vehicular communication. The

most challenging issue in VANETs is the security aspect. This paper is an effort in discussing the

security aspects in VANETs, the challenges, requirements and a possible solution to overcome e

the security aspects in VANETs.

Keywords: VANETs, V2V, V2I, RSU, DCF, PCF, Vehicular Public Key Infrastructure, Digital

Signatures.

*Computer Science Department, Rajagiri College of Social Sciences, Kalamassery, Kerala

** Computer Science Departments, Cochin University of Science and Technology, Cochin, Kerala.



1. INTRODUCTION

The innovations and improvement in the networking technologies has resulted in the

development of VANETs. VANETS (Vehicular Ad Hoc Networks) is a special kind of

MANETs (Mobile Ad Hoc Networks)) which aids in Vehicular Communication. Vehicular

Communication offers safer roads, efficient driving and easier maintenance. VANETs help in

saving time and money. The IEEE 802.11 Wireless standards are of high acceptance in today’s

academic and commercial standards. Driving cars includes two aspects: the first one being driver

assistance and car safety and the second one is infotainment for the travelers in the car (1). The

exchange of data and information between vehicles helps in the process of transferring real

time data. It also helps in communication about the road traffic and environment conditions.

VANETS also finds its applications in determining free parking slots and online help for car

maintenance. Research is also in progress for inter-vehicle communication. The field of inter-

vehicular communications (IVC), including both vehicle-to-vehicle communications (V2V) and

vehicle-to roadside communications (V2R), also known as VANET, is recognized as an

important component of ITS (Intelligent Transport Systems) in various national plans.(2) Traffic

fatalities are the leading causes of death in many countries. (3)This paper discusses the IEEE

802.11 standards for VANETS, the security problems that occurs in VANETs and the

countermeasures to overcome them.

2. VANET BASICS

Vehicular ad hoc networks are also known under a number of different terms such as inter

vehicle communication (IVC), Dedicated Short Range Communication (DSRC) or WAVE.(3) A

MANET is a self forming network which can function without the help of a centralized control.

Each node in this type of an ad-hoc network can act as both a terminal to store data and also as a

router. The nodes communicate through wireless medium in their specific radio range. VANETs

are a type of MANETs. As installing IEEE802.11 access points in all roads is expensive, it is

beneficial to go for an ad-hoc network. It also helps in quicker deployment. The greatest

challenge in creating a VANET is the rapidly changing network topology. The approximate time



period in which two vehicles are in the same communication range is approximately one minute,

which is a greatest challenge for implementing VANETS. The error-rate in wireless networks is

also comparatively higher. Another challenge is the limited ad-hoc mode provided by the

IEEE802.11 protocols.

3. WORKING OF VANETS

VANETS can be of V2V or V2R (also known as V2I- Vehicle-to-infrastructure) approaches. In a

V2V approach which requires zero infrastructures to outside devices is purely ad-hoc. In this

approach, vehicles communicate with each other to determine the traffic situation. The number

of vehicles needed to use the system to get quality information need to be determined. In the

second approach which employs both V2V and V2R requires roadside devices or units (RSUs)

as outside infrastructure. RSUs are usually placed in the traffic lights, road dividers etc. Using

this technology, vehicles can communicate with RSUs (also known as OBUs-On-Board Units)

and with other vehicles. Thus, a VANET is an ad-hoc network with vehicles, other network

services and applications (2).

Figure 1: Conceptual Schematic of a VANET

The IEEE has completed the standards IEEE P1609.1, P1609.2, P1609.3, and P1609.4 for

vehicular networks and recently released them for trial use. (4)

4. VANET APPLICATIONS

The three major areas of applications of VANETs are safety oriented, convenience oriented and

commercial oriented. (5) Safety applications include a Slow/Stop Vehicle Advisor (SVA) which



happens through V2V. Another safety application is Emergency Electronic Brake Light (EBBL).

Broadcast warning message about a vehicle involved in accident is done through Post Crash

Notification (PCN). Road Hazard Control Notification (RHCN) notifies other cars about road

slides, floods etc. Co-operative Collision Warning (CCW) alerts vehicles about potential crash

routes.

Convenience applications include Congested Road Notification (CRN) which alerts and notifies

congestion routes. Parking Availability Notification (PAN) helps in locating available parking

lots.

Commercial Applications include RVP/D, CMDD, RTVR and SA. Remote Vehicle

Personification/Diagnostics (RVP/D) downloads and uploads vehicle settings from/to

infrastructure. Content Map Database Download (CMDD) helps in obtaining information from

other stations. Real Time Video Relay (RTVR) helps in viewing videos for entertainment.

Service Announcements (SA) helps in giving alerts about gas stations, restaurants and restrooms

on the highway. (5) The U.S. Federal Communications Commission (FCC) recently allocated 75

MHz of Dedicated Short Range Communications (DSRC) spectrum, a one or two-way short to

medium range wireless communication channels at 5.9 GHz, to be used exclusively for V2V

and V2R communications(6).

5. MAC PROTOCOLS FOR VANETS

VANET Medium Access Control (MAC) protocols have to cater to the fast changing network

topologies and the different kinds of applications. VANET MAC protocols have to also reduce

the medium access delay for safety applications. Modifications need to be thus made to the MAC

layer to create wide scale VANETs, to share the wireless channel medium. It is the duty of the

MAC to ensure nodes from transmitting at the same time and to avoid collision. Due to the large

availability of cheap IEEE 802.11 based wireless devices, both the MAC and physical layer can

be addressed. (3)

Carrier Sense Multiple Access with Collision Detection (CSMA/CD) with acknowledgements

helps the network in avoiding collisions. Two protocols namely Distributed Co-ordinate

Function(DCF), a contention based, easy to implement access protocol where all the nodes

planning to send data compete for the channel, and Point Co-ordinate Function (PCF), a



contention free protocol , which is not applicable to ad-hoc networks are defined by 802.11

standards. (7)

5.1 IEEE 802.11 Standards

IEEE defines a MAC sub layer, protocols and services for the WLANs and three physical (PHY)

layers. The SME (Station Management Entity) and MLME (MAC Layer Management Entity)

control the MAC sub layer.

The IEEE working group has now come out with the 802.11p, an approved amendment (2009) to

the IEEE 802.11 standard for implementing wireless access in vehicular environments (WAVE),

the next generation dedicated short-range communications (DSRC) state-of-the art technology to

support VANETs. IEEE 802.11p includes vehicular safety applications, data transfer enabled

through V2V and V2R, in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz). The IEEE

802.11p also states that in the United States proposes that the information about an accident

should be communicated through VANET within half a second to all equipped vehicles in 500

meters range. (7) 802.11p will be used as the groundwork for DSRC based on the ISO CALM

architecture standard looking at vehicle-based communication networks, particularly for

applications such as toll collection, vehicle safety services, and commerce transactions via cars.

(8) CALM is an acronym for Continuous Air interface for Long and Medium distance. WAVE

uses the CSMA/CA as the basic medium access scheme for sharing links between vehicles and

stations.

6. INTER VEHICLE AND INTRA VEHICLE COMMUNICATION

Communicating vehicles can be possible by microwaves for broadcast communication and

infrared for directional communication, though microwaves are used more often (9). Bluetooth

technology is also used widely. Communication requests can be refused due to the master/slave

setup of Bluetooth. Directional MAC (DMAC) protocol, which uses only directional

transmissions (10) helps in avoiding hidden terminal and deafness problems among nodes. A

Circular Request to Send (CRTS) consisting of RTS-CTS-DATA-ACK is sent directionally. The

source transmits its data when it receives Clear to Send (CTS) message. Though DMAC should

have better performance, it is hindered by mobile portability. (10) The Adaptive Space Division

Multiplexing (ASDM) addresses the denial of Service (DoS) attacks. It is an extension of Space



Division Multiple Access (SDMA) where time slots are assigned based on the location of

vehicles on the highway.

Communication functions inside a vehicle can be performed using the wireless technologies.

IEEE 802.15.1(Bluetooth), IEEE 802.15.3(UWB (Ultra Wide Band), high data rate) and IEEE

802.15.4 (ZigBee, low data rate) can be used for the inter vehicle communication. Bluetooth

which is a proven, cheap technology can transmit both voice and data with good security

features. The power requirement is low and security features are good. It conforms to the

Frequency Hopping Spread Spectrum (FHSS) mode and supports star topology and has error

correcting mechanisms (11).

7. SECURITY REQUIREMENTS IN VANETS

Similar to any other networks, VANETS are also vulnerable to attackers and adversaries. The

CIAN (Confidentiality, Integrity, Availability and Non-Repudiation) are of most importance to a

VANET.

Confidentiality- It ensures that information is accessible only to those nodes authorized to have

access. It prevents unauthorized access. Not all data are confidential but critical data require

confidentiality. This type of access includes printing, transmitting, displaying and other forms of

disclosure, including simply revealing the existing of a vehicle.

Integrity and Authentication – It ensures safeguarding the accuracy and completeness of

information and processing methods. Data cannot be modified.

Availability – Availability ensures that authorized users have access to information and

associated assets when required. Availability requires that vehicle details are available to

authorized parties. Availability is a requirement intended to assure that systems work promptly

and service is not denied to authorize users.

Non Repudiation – The sender of the message cannot deny having sent the message. It ensures

that a transferred message has been sent and received by the parties claiming to have sent and

received the message. It guarantees that the sender of a message cannot later deny having sent

the message and that the recipient cannot deny having received the message.



Privacy and Anonymity: Drivers of vehicles will not want their personal information accessed

by other users or drivers of other vehicles. As all these information are included in the

transferred data among vehicles, it is possible that the driver of a particular vehicle can be traced

down, thus raising issues to his privacy and anonymity.

Real time Constraints: Vehicles should transmit only real time data based upon real time

constraints. Old data and outdated messages have to be eliminated by the network.

8. SECURITY CHALLENGES IN VANETS

The degree of attack is more, as a variant of the IEEE 802.11 protocol is used. Here in this paper,

we explore the various kinds of vulnerabilities and challenges VANETS are prone to.

DoS Attacks- DoS Attacks are often executed for no obvious reasons in VANETs. This can be

overcome to an extent by switching between channels. Here, networks are jammed by sending

dummy messages

Bogus Information: Attackers diffuse false information to divert other drivers on the highway

and to thus get a clear road ahead for themselves.

Hidden Vehicle: This is a type of sophisticated attack where vehicle A meets with an

accident/crash and broadcasts warning messages to other vehicles. Vehicle B, on receiving the

broadcast message from vehicle A dissuades A from further broadcasting by pretending to be in

a better position than A, for broadcasting the accident message. Thus, A stops broadcasting, on

the belief that B would do the service, and thus playing a role in reducing congestion. So, A is

hidden to other vehicles. (12) Here, there is a c chance that other vehicles are not informed in

time, thus disabling the system.

Tunneling: As transmission of messages and signals disappear in tunnels, false data can be

transmitted by attackers before the vehicle enters the tunnel. The concept of double tunneling

(wormhole) (13) is also prevalent in VANETs.

Sybil Attack: In this type of an attack, vehicles forge their identities. This mostly happens when

there is a Certification Authority (CA) to verify the identity of users. This usually occurs when a

vehicle can get more than one digital signature from the same CA. (14)



Big Brother Scenario: This involves the monitoring of the patterns of targeted vehicles for

constructive (e.g.: car-rental) or destructive (e.g.: terrorism) purposes.

Delay: As the connection in V2V and V2I are done mostly using thee Bluetooth technology,

there would be a connection setup delay of not more than 3 seconds between users. This would

also count up to the master/slave architecture used among the vehicles.

Logical Attacks: Logical attacks are triggered by external attackers who attack the wireless

communication and internal attackers who attack the on-board software interfaces (15). Though

security mechanisms are applied to the software, the increase in software complexity is the main

reason that is being exploited (16). Software attacks which arise due to the design,

implementation and interface (11), active and passive attacks on the VANETs and the

communication channels, eavesdropping, fabrication, replay attacks etc are the main issues faced

by VANETs.

Physical Attacks: Physical or hardware attacks are attacks done to the physical on-board unit. It

can be an active, passive, invasive or non-invasive attack (16). Physical attacks can also take

place in the in-vehicle networks where damage can be done to the components of the on-board

units. (12)

Masquerading: An attacker can pretend to have the identity of another vehicle by using false

identities, and thus misleading another vehicle. (13)

Adversaries: There can be greedy drivers who broadcast false messages and information

convincing the neighbors that there is congestion ahead and to take alternative paths, so as the

road ahead is clear for the greedy driver. Driver profiling and tracking is not acceptable to all

users. There are the possibilities of drivers to play pranks and hack information. Malicious

programs can be uploaded by mechanics when the vehicles go in for maintenance. There can also

be malicious attackers like terrorists and criminals who would want to track down specific

vehicles for selfish destructive needs. Message packets can be selectively dropped so as to

suppress congestion alerts. Existing data can be altered by fabrication or by replaying previous

stream of data.

9. SECURITY ISSUES- CHALLENGES



There have been several studies regarding the threat model, Authentication and key management,

Privacy and Secure positioning of VANETs. Authentication and privacy is of most concern in

VANETs as the network would want to bind each driver to a single entity. The availability of

only 50-60% (13) of vehicles neighbors that would receive a broadcast message in DSRC is also

a problem. The low tolerance for error in collision avoidance/warning systems is also a

challenge. High mobility of vehicles in the VNET network with constantly shifting set of

neighbors is a challenge for VANETs. Key distribution also poses threats as to where and how

many keys to install. The Certification authority (CA) of the PKIs is also a point of argument in

VANETs.

10. COUNTERMEASURES TO VANET SECURITY ISSUES

The security of Vehicle Communication is mainly based upon three aspects - the hardware,

devices like ECUs, sensors, actuators, gateways, etc., the software or firmware which operates

and controls the ECU behavior and the communication channel for different communication

types including V2V, V2I and in-vehicle. There should be an in-vehicle security module within

each vehicle which has IDS (Intrusion Detection System) and a firewall (17, 18). The IDS should

be able to add rules to the firewall table dynamically to deny or disable a service. As vehicles

have a long lifespan, it is hard to change its on-board systems regularly. There is also the risk

that owners can try to modify or enhance their vehicles. No technical expertise is required from

the user of a VC system. (19)The alerts and messages should be readily alerted and taken action

as a real time system. Liability and conformance of a VC system can also formulate legal and

financial issues (20, 21). VC security mechanisms should be flexible to allow later modification

to the changing security requirements.

To address this aspect, we can employ the use of substitutive cryptographic algorithms (22,23)

for the vehicles. In today’s scenario of car manufacturing, vehicles cannot be equipped with the

latest state-of-the-art technology processors, as the vehicle cost will rise drastically. Digital

Signatures and tamper proof devices should be used in the processors built in vehicles (12).

Inclusion of Electronic License Plates (ELP) (24) for vehicles can ensure cryptographically

verifiable number plates to track vehicles when they are speeding on the highway or when it is



stolen. The Vehicular Public Key Infrastructure (VPKI) (22)can be ensured in which a

Certification Authority (CA) ensures the distribution of keys, key management, certificate

revocation etc. Data Correlation techniques can be used to keep track of bogus information

records. Verifiable multilateration techniques can be used for secure positioning of vehicles.

Acknowledgements

1. Rainer Baumann,”Vehicular Ad hoc Networks”, ETH Zurich 2004

2 Yi Qian, Kejie Lu, and Nader Moayeri, “A Secure VANET Mac Protocol For DSRC

Applications”

3. Nathan Balon, “Introduction to Vehicular Ad Hoc Networks and the Broadcast Storm

Problem”

4. IEEE Draft P1609.0/D01, February 2007.

5. Mainak Ghosh & Sumit Goswami, “Intelligent Transportation using VANET”, IIT, Kharagpur

6. Dedicated Short Range Communications (DSRC)

http://www.leearmstrong.com/DSRC/DSRCHomeset.

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19. Maria Fazio, Claudio E. Palazzi, Shirshanka Das†, Mario Gerla, “Facilitating Real-time

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for Applications and Management Messages, November 2005.

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