• No results found

Using Social Network Information to Improve the Performance of P2P Networks

N/A
N/A
Protected

Academic year: 2021

Share "Using Social Network Information to Improve the Performance of P2P Networks"

Copied!
85
0
0

Loading.... (view fulltext now)

Full text

(1)

Masters Dissertation in Engineering

Using Social Network Information to Improve

the Performance of P2P Networks

February 2008

Fatmawati Zifa Zaukani

Technology Management, Economics, and Policy Program College of Engineering

(2)

Using Social Network Information to

Improve the Performance of P2P Networks

지도교수 이정동

이 논문을 공학석사 학위논문으로 제출함

2008

2

서울대학교 대학원

협동과정

기술경영경제정책과정

Fatmawati Zifa Zaukani

Fatmawati Zifa Zaukani의 석사학위논문을 인준함

2008

2

위 원 장 _____________________(인)

부위원장 _____________________(인)

위 원 _____________________(인)

(3)

To everyone who matters. This is for you.

It concerns us to know the purpose we seek in life, for then, like archers aiming at a definitive mark, we shall be more likely to attain what we want.

(4)

Using Social Network Information to

Improve the Performance of P2P Networks

Fatmawati Zifa Zaukani

Abstract

Recognizing the importance of social network theory is becoming significant to overcome some problems in current P2P system implementations. Our work will explore the advantages of overlapping boundaries between the two separate fields of social networks and peer-to-peer networks. In order to achieve these objectives, we propose our model and research idea, where our model will be based on a current P2P system implementation, and the idea is a proposal to apply social network theory and information into the model. Our aim is to build a good model of P2P system development, considering technology and human behaviour as well.

We conduct a survey in intention to obtain the possible accountable data for our work. This is to assist us in identifying the factors (or social network information) which can be used for our model, and later we evaluate the outcomes by using a multiple regression analysis. The result based on the analysis will be the framework of our suggestion and recommendation for our stated research problem. The major contribution of this work is to provide an effective framework for P2P systems with social network information applied.

The proposed model will aid potential system developers to identify the interrelationship between the factors of social behaviours and technology, which could contribute to a performance increase in P2P systems. We present the results of applying

(5)

social network information in addressing the performance issues in a P2P system by using Skype as our case study.

This work will begin with an introductory chapter that mainly discusses peer-to-peer networks and social networks in general, research motivation, problem descriptions, research objective, and the questions that triggered this research. The following chapters will discuss the research work, including literature reviews, research model, and the survey analysis. We will also look into the implication of the research and discuss some recommendations and suggestions. Finally, the final chapter will conclude the research and suggest some future extensions to this work.

Keywords: Peer-to-peer networks, social network, social network systems, Skype, KaZaa, survey, multiple regression analysis.

Student Numbers: 2006-22703

Technology Management, Economics, and Policy Program (TEMEP) College of Engineering

(6)

Table of Contents

Abstract ... i

Table of Contents ... iii

List of Tables ... vi

List of Figures ...vii

Chapter 1: Introduction ... 1

1.1. Overview ... 1

1.2. General Concepts ... 1

1.2.1. Peer-to-Peer (P2P) Network ... 2

1.2.2. Social Network ... 6

1.2.3. P2P Network and Social Network... 8

1.3. Research Motivation ... 9

1.4. Problem Description ... 9

1.4.1. Case Study: Skype ... 10

1.5. Research Objective ... 13

1.6. Research Questions ... 14

1.7. Research Methodology ... 14

Chapter 2: Literature Reviews ... 17

2.1. Overview ... 17

2.2. Literature Review on P2P Networks ... 17

2.3. Literature Review on Social Networks ... 18

2.4. Literature Review on P2P and Social Networks ... 18

(7)

Chapter 3: Research Model ... 21

3.1. The Idea ... 21

3.2. The Model ... 23

Chapter 4: Survey and Data ... 26

4.1. Introduction ... 26

4.2. Principle of the Survey ... 27

4.3. Survey Indicators and Input Variables ... 28

4.3.1. Survey Indicators ... 29

4.3.2. Independent Variables ... 30

4.3.3. Dependent Variable ... 30

4.4. Questionnaire Set ... 31

4.4.1. Capturing Personal Opinion towards Skype ... 32

4.4.2. Capturing Personal File-Sharing Activity ... 33

4.4.3. Capturing the Willingness to Share Resources ... 33

Chapter 5: Analysis and Result ... 35

5.1. Introduction ... 35

5.2. Survey Feedbacks ... 35

5.3. Descriptive Analysis ... 36

5.3.1. Analysis on Users Sophistication in Using Online Communication Applications ... 36

5.3.2. Analysis on Personal Opinion towards Skype ... 41

5.3.3. Analysis on File Size Transfer using Skype... 43

5.3.4. Analysis on Super Node Awareness ... 44

5.3.5. Analysis on Resource Sharing Willingness ... 45

5.3.6. Analysis on Conditions to be a Super Node ... 47

5.3.7. Analysis on Important Factors in Being a Super Node ... 48

5.4. Multiple Regression Analysis (MRA) ... 49

(8)

5.4.2. Research MRA Model... 52

5.4.3. The Result ... 53

5.5. Key Findings of the Research ... 56

5.5.1. Compliance of the Research Work ... 56

5.5.2. Parameters Estimators ... 57

5.5.3. P2P-with-social-network-applied System Development Framework ... 58

Chapter 6: Conclusion and Outlook ... 59

6.1. Summary on Research Work ... 59

6.2. Contributions and Implications of the Research ... 59

6.3. Suggestion for Future Work ... 60

6.4. Conclusion ... 61

Bibliography ... 62

Additional Bibliography ... 66

추상적 (국문 초록) ... 67

Appendix A: Survey Variables ... 69

Appendix B: Survey Questionnaire Set... 71

(9)

List of Tables

Table 1.1. P2P Features & Advantages ... 5

Table 1.2. Scenario I (Summary) ... 12

Table 3.1. Results on File Transfers ... 21

Table 3.2. Scenario II (Summary) ... 24

Table 4.1. Survey Indicators ... 29

Table 4.2. Suggested Independent Variables ... 30

Table 4.3. Suggested Dependent Variable ... 31

Table 5.1. Possible Independent Variables for MRA ... 51

Table 5.2. Redefined of Selected Independent Variables ... 52

Table 5.3. Model Descriptive Analysis ... 54

Table 5.4. Model Summary ... 54

Table 5.5. Analysis of Variance (ANOVA) ... 55

(10)

List of Figures

Figure 1.1. Centralized Architecture ... 3

Figure 1.2. Decentralized (Pure) Architecture ... 4

Figure 1.3. Hybrid Architecture ... 4

Figure 1.4. Skype Architecture ... 11

Figure 1.5. Skype Environment ... 13

Figure 1.6. Research Framework ... 16

Figure 3.1. Research Idea ... 23

Figure 3.2. Research Model ... 24

Figure 5.1. Skype Usage Frequency Analysis ... 37

Figure 5.2. Other Similar Applications Usage Analysis among Skype Users ... 38

Figure 5.3. Cumulative Percentage on Skype Functions Usage ... 39

Figure 5.4. Cumulative Percentage on Group Formation in Contact List ... 40

Figure 5.5. Percentage on Total of Contact List Size in Skype ... 41

Figure 5.6. Cumulative Percentage on Analysis on Personal Opinion on Skype ... 42

Figure 5.7. Size of File Transferred using Skype ... 43

Figure 5.8. Percentage on Awareness of Being a Super Node ... 44

Figure 5.9. Cumulative Percentage on Resource Sharing Willingness ... 46

Figure 5.10. Cumulative Percentage of Conditions to be a Super Node ... 47

Figure 5.11. Important Factors in Being a Super Node ... 48

(11)

Chapter 1:

Introduction

1.1.

Overview

Peer-to-peer technology has attracted many attentions for the advantages it offers and its capabilities to share resources in an economic way. To date, this area is still widely open for interesting possibilities, opportunities and new ideas to be explored. Apart from being a very promising technology that overlay the Internet infrastructure, peer-to-peer network experienced many problems that impede its success to fulfill the expectations.

Interests in social network area are also increasing in recent years. The hidden power of social networks; waited to be discovered and benefited, will help in addressing the critical interactions that occur in a network. Social network analysis will give the inputs and snapshots of the available information in the network, then ideally will provide the opportunity to tap into the potential right solution for certain problems. Researchers have been studying on how to leverage the invisibility in social networks in order to manage the outcomes and results for better future insights.

This chapter will begin with a section that explains the general concepts of the networks. Then, we will discuss our motivation to pursue this work, followed by the problem descriptions and the research objective that enlightens our direction. Finally, we fronted the questions we try to answer within the scope of this research and followed by explanation on the methodology used to find the solution for the problem.

1.2.

General Concepts

There are two major keywords that will be used throughout our work, which are peer-to-peer networks and social networks. We will discuss the concepts from various definitions, the architectures and the assumptions in studying the networks. Later, through the explanation on both networks, we will be able to discuss the similarity between the networks. This is important in order to give a level of

(12)

understanding to the readers, which will assist further readings to the next following chapters.

1.2.1. Peer-to-Peer (P2P) Network

Peer-to-peer1 technology is designed to access distributed resources in a very economic way. Researchers look forward into the possibilities and opportunities offered by P2P technology, mainly for developing new Internet-based applications [1] to replace the client-server technology. P2P is fast in gaining its popularity because it functions “to pool together and harness large amounts of resources” [2], while the connections among peers (or computers) are done in an ad-hoc manner from distributed environment, without using the centralized servers. In [3], the basic definition of a P2P system is “a self-organizing system of equal, autonomous entities (peers) aims for the shared usage of distributed resources in a networked environment avoiding central services”.

Intel P2P working group defines P2P as “the sharing of computer resources and services by direct exchange between systems” [3], where this technology offers the economic way of file (and most importantly, resource) sharing across huge networks without the needs for expensive hardware like servers. P2P also referred to as “a class of systems and applications that employ distributed resources to perform a critical function in a decentralized manner” [4].

P2P systems are designed based on unstructured network and structured network. Unstructured network attracts more intentions because it offers scalability as its best feature. Furthermore, it offers researchers opportunities to study and propose many innovations in developing P2P systems. In the unstructured network, there are three (3) types of architectures, which are centralized, pure and hybrid architecture. These architectures are described as below:

i. Centralized Architecture.

– The network contains a central server that connects to all peers in the

1

(13)

network. The central server is responsible in keeping the records of all peers in the network. Figure 1.1 presents this architecture.

Figure 1.1. Centralized Architecture

– Once a peer enters the network, it will establish its connection with the central server. This architecture uses the client-server mechanism for the tasks like searching, and P2P mechanism for other activities such as file uploading and downloading. The central server will have the authority to control the information exchange, while data flow activities will occur among the peers.

– Some examples of the applications that are designed based on this

architecture are Napster, iMesh and Audiogalaxy.

ii. Pure (Decentralized) Architecture:

– The decentralized (some may refer to ‘pure’) architecture is the

solution the overcome centralized architecture problems. Figure 1.2 presents this architecture.

Peer

Peer Central

(14)

Figure 1.2. Decentralized (Pure) Architecture

– The structure of this architecture is “radically decentralized” [3] and very complex. The failure or shutdown of any particular peer does not impact the rest of the system because existing and connected peers will self-organize and build up the network again.

– Some examples of the applications that are designed based on this

architecture are Gnutella 0.4 and Freenet.

iii. Hybrid Architecture:

– A combination of pure and centralized architectures have been

proposed and implemented to have better a performance in P2P networks. The central server will play important role in the network, but unlike the centralized architecture, hybrid architecture allow unlimited numbers of central servers. Figure 1.3 presents this architecture.

Figure 1.3. Hybrid Architecture

– A peer with high resources (i.e. computing power, bandwidth, etc.)

will be selected as a central server, or better acknowledged as a super peer. This architecture is also claimed can overcome the manageability problems in the previous two P2P architectures.

– In this environment, once a peer enters the network, it will be

connected to a number of super peers. This peer is acknowledged as ordinary peer (or leaf node). A super peer will maintain a number of

Peer Super

Peer Super

(15)

ordinary peers and form a group. The connection between groups is done between super peers.

– Some examples of the applications that are designed based on this

architecture are Gnutella 0.6 and FastTrack protocol.

P2P technology offers many advantages. Its distinguishing features may also relate to its advantages. It is scalable because of its decentralized and distributed nature that resulted to no limitation of its size compared to the client-server technology. Table 1.1 will summarize the features and advantages of a P2P network.

Table 1.1. P2P Features & Advantages Feature and

Advantage Description

Scalability

System will have no algorithmic or technical limitation regarding the size. The complexity of the system should be constant regardless of the number of nodes in the system.

Resource availability

Clients/peers/nodes provide resources (i.e. files, bandwidth, storage space, and computing power). Nodes arrive and increase the demand on the system and increase in the total capacity of the system.

Load-balancing

The system workload performance algorithm is built to support equal capability and distributed load among peers in P2P network.

Distributed environment

No central authority where communication between peers occur directly.

Large-scale and complex system

An open system with an anarchist topology which contributed to difficulties in analyzing the properties. Related information is very hard to describe theoretically.

Self-organized, robust and resilient

Nodes are self-organized within the same group occasionally over time, contributing to the robustness and resilience of the network.

Autonomy and Nodes join the network and obey a set of rules in

(16)

Feature and

Advantage Description

anonymous their autonomy as individuals. Nodes also appear to be

anonymous to protect privacy.

Dynamic, adaptability and fault tolerant

The formation change rapidly and in continuous renewal. Peer can enter and leave the network at any time. Able to react to perturbations appropriately, i.e. peers restructuring, peers’ authorization etc. Adapts to arrivals, departures and failures of nodes/peers automatically. In short, no single point of failure in the system.

These advantages are the main factors for system developers to design their applications and systems based on P2P technology. It is obvious that P2P technology is offering economic environment in implementing a large scale system, compared to the client-server technology. Client-server technology needs more expensive equipments in its implementation, and is not exploiting the rich and available resources in the network the way P2P technology did.

1.2.2. Social Network

Social network is “a social structure made of nodes that are tied by one or more specific types of interdependency” [5]. ‘Nodes’; in this context, generally may refer to individuals or organizations. ‘Interdependency’ may refer to values, visions, idea, financial exchange, friends, kinship, dislike, conflict, trade or any other factors or characteristics that a social network researcher may want to study. Social network is also defined as a set of people, organizations or other social entities, connected by a set of socially meaningful relationships (i.e. friendship, co-working or information exchange, and interactions).

A book club consists of ten people is a social network, where these people share the same interest. This community may become bigger in time, and the interactions may become more complicated as the network grows. In [6], the authors

(17)

argue that the relationships among nodes are depending on “the characteristics of the individuals and their interactions”. Therefore, in doing a social network research, one must assume that:

i. Actors are interdependent, and

ii. Behaviors and outcomes are understood through the relationship with

others.

Since the term “social network” firstly highlighted by J. A. Barnes in his study entitled “Class and Committees in a Norwegian Island Parish” (1954), this area has gained increased intention. The study of social networks has expanded from social theories and has converged itself into variously different disciplines such as mathematics, biology, business management and of late: computer science and information technology.

Social Network Information (SNI)

Social networks contain many invaluable inputs and information. The networks are created, managed and evolve in a self-organized manner, where these processes eventually lead to better desired outcomes, particularly by sharing expertise, resources, and information [7]. The available information will show the interaction patterns in the networks, how the people are interconnecting with each other, how their mutual interest will benefit the networks by attracting larger crowds, as well as enable any interested parties to gather the collective knowledge for their own purposes (such as for business opportunity, professional networking etc.).

Moreover, the analysis of the available social network information could benefit academia, such as in the studies of agent-based models, knowledge management, semantic webs or system and application development, among many others areas, too.

In short, social network information is the encyclopedia that provides inputs to describe the social structure, where the outcome of the analysis is used “to provide formal models that capture the common properties of all (social) networks and a set of

(18)

methods applicable to the analysis of networks in general” [8].

1.2.3. P2P Network and Social Network

In this section, a general description on overlapping area between peer-to-peer network and social network will be explained. We will look at the similarities between both networks that worth fair attention throughout doing this research. In addition to that, social network theory will be the essence of this work, on how this area will give significant impacts on a P2P system, which will be discussed further in the next following chapters.

An actor in a social network is referring to a peer in a P2P network. The reason beneath this statement is the activity between two peers can be considered as a relationship (or tie) between two actors that share common interest. This is also highlighted in [9] by stating that a collection of peers may contain few nodes that belong to the subset of other group at the same time is “similar to human social networks”.

Recently, many literatures proposed a combination of P2P and social network, which created the ‘peer-to-peer social networks’ wave in the research area. Some researchers include ‘community’ concepts to study P2P network, where these P2P communities are created based on the clubs that belong to the same interests. “Communities are created, implicitly when one or more entities claim an interest in the same topic” [10].

P2P network is an open and evolving society of nodes that assemble into a social network of resource sharing and pooling for mutual benefit, where this resources normally represented by available data in the network. Interaction in P2P is very much resembles the “interaction in real world communities” [11]. Human are communicating in a group that share common good and interests.

It is also emphasized that the P2P networks “are considered as emerging social network for pooling network and information resources” in [12]. For all of these reasons, it is significant to consider both social network and P2P are dynamically

(19)

created, therefore will allow us to see how both networks resemble each other in order to propose the appropriate solution in this paper.

1.3.

Research Motivation

The convergence of both P2P and social network; as claimed by many literatures recently, has promised better technology deployment of P2P systems in the future. Apparently, the idea of implementing the combination of both networks has also raised some questions and issues. What is the best strategy in applying social network theory in a P2P development? What are the best social network properties that should be considered in a P2P system? How will the new result; based on P2P systems with social network, be applied, significantly different from the current implementation? Hence, our work will propose a solution to answer and tackle these issues.

This works is initially motivated by our enthusiasm as Skype users. We have noticed from our observation that studying Skype has opened a lot of opportunities awaited to be explored. Moreover, the P2P technology used in Skype’s overlay network implementation is a good example that makes Skype different and outstanding from other similar applications. It also contributes to Skype’s high quality of services compared to its competitors. According to these reasons, in our opinion, Skype will be the best case study that allows us to experiment with our main idea: using the social network information in a P2P system development.

1.4.

Problem Description

Existing P2P networks emerge particularly triggered by the need of resource sharing in a simplest way among distributed environment, with the minimal cost possible. P2P systems also are designed to be anonymous “to ensure that the identity of the agent who performs some action remains hidden from other observers” [13]. This feature benefits the interaction process in a very large environment, while keeping the “network interactions privacy and secrecy” [2, 14].

(20)

Besides, P2P systems are also designed to be autonomous and fault tolerance, to cope with the dynamic environment caused by peers entering and –leaving the system. In studying a P2P system, one must be aware that P2P network is dynamic in nature and pose great challenges of “large populations, high turnover, asymmetry of interest, collusion, zero-cost identities, and traitors” [15].

Despite of the fact the P2P systems are developed and designed to exploit the advantages and features as described in Table 1.1, many of these P2P systems are still facing performance-related issues. Technology enhancement alone is not a solid solution to overcome the performance issues. The performance in P2P networks depends on two factors, which are technology and user behaviour [16]. This triggers the idea of applying social network theory in implementing P2P systems [16, 17, 7].

Our work will look into the possibility of applying social network information into a currently existing P2P system. We will evaluate a case study that implements P2P technology and propose our model and later, will analyze outcome of the findings based on our proposed model. Therefore, we will study Skype to aid further understanding of the significance of our research objective and subsequently to answer the research questions.

1.4.1. Case Study: Skype

Skype [16] is a Voice-over-Internet Protocol (VoIP) application that is designed using FastTrack protocol and implemented based on KaZaA. It is an overlay P2P network application that enables high quality telephone conferencing, instant messaging, file transfer, short message service and video conferencing. Skype is very popular mainly because of its ability to bypass network address translators (NAT) and firewalls (hereafter, both will be acknowledged as NAT2).

Skype is considered as proprietary software, because its development blue

2

Network Address Translation (NAT) is developed to solve IPv4 shortage problem. It converts IP addresses and port numbers in IP headers by turning all packets into a single public IP address, despite of the actual source or destination. NAT is located between the public Internet and private network. It secures the network by disguising the internal and external network.

(21)

prints and documentation are not available publicly. One may conclude that Skype has similar protocol with KaZaA, particularly because the inventors of KaZaA are also the inventors of Skype. Both KaZaA and Skype apply two-tier hierarchical system that consists of super node (hereafter will be acknowledged as SN) and ordinary node (hereafter will be acknowledged as ON) architecture.

The above described architecture is presented in Figure 1.4.

Figure 1.4. Skype Architecture

The architecture can be described as:

i. Super node (SN) is a node3 that has high resources and capabilities such as high bandwidth, storage capacity, or processing power and non-NATed accessibility, and publicly reachable by any peers in Skype network. ii. Ordinary node (ON) is a node with less resources and capabilities. The ON

will connect to the appointed SN by the Skype, once it enters the network. In many cases, NAT will disable P2P communication. This will make the peers behind the NAT are usually unreachable for the peers with globally valid IP addresses [18]. Once Skype encounters this situation where one peer is located behind the NAT, Skype will use relay nodes approach to enable the interactions among the peers in its network [19]. A peer with higher resources will be selected as a SN and

3

‘Node’; in the context of this work, can also be referred to as ‘peer’ or ‘computer’. All words will bring the same meaning hereafter.

Ordinary Node (ON) Super Node (SN)

Skype Login Server

(22)

will act as the bridge between the ONs thus, enables the interactions to occur.

In this research, we will analyze Skype accordingly the work of [20]. We begin the discussion with a current model implementation of file sharing activity in a Skype environment. It is informed previously that any nodes with higher resources will be automatically chosen to be super nodes in a Skype network. Anyway, in order to limit the burden of the super nodes in the network, the file transfer total speed is limited to 5 kb/sec only.

We will consider this file sharing activity based on Scenario I. A node; Node A, is located in a public network whereas another node; Node B, is located behind the NAT in a private network. Node A wants to send a file to Node B. Node A has to locate the super node of Node B; which is Super Node Y, through its super node, Super Node X. Super Node X will find Super Node Y. After that, Node A is capable to send the file to Super Node Y. Super Node Y will forward the file to its node, Node B. Node B will receive the file through Super Node Y, and the Super Node Y will acknowledge Node A.

Table 1.2 presents the summary of Scenario I.

Table 1.2. Scenario I (Summary)

1. Node A wants to send file to Node B. Node A has to locate the super node of

Node B through its super node, Super Node X. The super nodes selection is done automatically by Skype.

2. Super Node X finds the super node of the Node B, Super Node Y.

• In order to do so, Super Node X will use designated searching algorithm

(i.e. flooding message, random walk etc.) to find Super Node Y.

3. Node A sends the file to Super Node Y directly.

4. Super Node Y forwards the file to its node, Node B.

5. Node B acknowledges and receives file from Super Node Y.

(23)

The whole process of the Scenario I can be overviewed as in Figure 1.5.

Figure 1.5. Skype Environment

Scenario I will be the reference of our work, where we will consider proposing our idea and model based on the current performance issues in the current Skype environment.

1.5.

Research Objective

The objective of our work is to demonstrate that social network information could contribute to address the performance issues in peer-to-peer (P2P) networks, by taking Skype as a case example.

Fi re w al l/ N A T Node B Node A Super Node X Private Network Super Node Y Firewall/NAT

5

4

3

2

1

6

(24)

1.6.

Research Questions

The research is conducted to seek answers for the following questions:

i. Can social network information improve the performance of a P2P

system? Which social network information should be considered? We are interested to study the impact of social networks in a P2P system implementation. Based on our model, we create a survey, which later is used to obtain all possible factors. The analysis could contribute to proposing the appropriate model that considers social behaviours in a P2P technology deployment.

ii. If so, under what condition, when and how it can be applied? With

whom, or how much are people willing to share their resources?

Human and the social behaviours are hard to predict and measure. We are interested to see how social behaviors and technology will influence each other in a P2P network. Based on the data of the social network information obtained, we will be able to identify the answers for these questions.

iii. Are the factors identified can improve the design of current P2P

system? What can be inferred from the newly proposed P2P topology with social network information? The analysis from our study will provide a framework for the new topology formations in a P2P network. The new topology proposed from applying social networks will give a preliminary evaluation on the P2P system development in the future.

1.7.

Research Methodology

The methodology used in this research consists of several steps, which are: i. Literature reviews. An intensive review of journals and publications will

(25)

network applied, and Skype. Chapter 2 will give a further description about literature reviews.

ii. Research idea and model. We propose and develop our idea and research model to achieve the research objective and answer the research questions. Chapter 3 will discuss about the related information.

iii. Survey. A survey will be conducted to assist our work in obtaining possible information to strengthen our proposed solution. This survey, at the same time, will be used to gather and identify the appropriate social network information, which later will be used in deploying a P2P system. The questionnaire set is intentionally designed to include as many information about social network as possible. Chapter 4 will explain more about the survey.

iv. Result analysis and comparison. Based on the feedbacks obtained from the survey, we will use multiple regression analysis on the data and finalize the report for our work. Result will be analyzed by using a multiple regression analysis. A series of experiments with various possible independent variables will be evaluated to see their interdependencies with the dependent variable. Chapter 5 will include all explanation about the analysis and result.

In general, our work is conducted by following the steps described above and is implemented accordingly to our research framework, as presented in Figure 1.6.

(26)

Figure 1.6. Research Framework Literature reviews Research idea and model Conducting a survey Result analysis and comparison

Literature reviews and readings on related topics in this work, such as P2P, social network, P2P and social network, and Skype. The purpose is to gain deep understanding about the topics, in order to propose the appropriate solution, as well as to achieve research’s objective.

We propose our research idea and research model that will allow us to manipulate and apply the social network information into a P2P system.

A survey is conducted to get feedbacks from our targeted group: a population of students.

Variables from the survey feedbacks will be analyzed by using a multiple regression model. A series of experiment and analysis will be conducted in order to identify the variables which can simulate a more conducive resource sharing environment.

(27)

Chapter 2:

Literature Reviews

2.1.

Overview

This section will discuss about the current research regarding P2P, social network, P2P with social network applied, and Skype.

2.2.

Literature Review on P2P Networks

The works of [4] and [21] provide the best fundamental knowledge about P2P networks. The papers discuss comprehensively all needed information to understand P2P systems, defines all related matters through terminology, architectures, goals, components, and challenges. It also provides some case studies, and tips on challenges based on the lessons learnt. In addition, the papers also give clear and complete survey of P2P networks according to the clues of its development and evolution process.

Authors in [22] give an overview on understanding one of the highlighted features of P2P network which is dynamism by analyzing Maze log dataset. Some of the findings are the previous measurement did not include appropriate system dynamic properties, high available peers do not have diurnal online patterns, join and leave is very frequent and aged peers are more stable than young peers.

The rational that lies beneath our work is based on the works of [10], [16] and [23]. In [10], the authors focus on efficient method to discover P2P communities by proposing an algorithm based on interest similarity among peers. Interest is divided into 3 classes of attributes (personal, claimed and group). While in [16], the paper proposes a model that combines club economics approach with information retrievals computer science literatures, as continuity to the authors’ previous work (2003), which is focusing on interest-based P2P self-organization. The authors define ‘utility’ to measure peers’ information needs and use it to cluster clubs accordingly and conceptualize the network as ‘a collection of interconnected clubs operated by

(28)

‘ultrapeers’. In [23], the authors analyze the economics of P2P networks from the aspects of incentives, user behaviours and motivation, reputation and trust, and intellectual property. P2P networks have been the important tool to share/distribute contents. Authors also emphasize that P2P networks researches in social and economic analysis are still few but very crucial to develop efficient protocol and systems.

2.3.

Literature Review on Social Networks

Analysis on different cases of social networks will give different outputs and interpretations as in [24]. The result shows that different cases will give different outputs. Therefore social network application developers should understand various data collection techniques will affect social network in the real world.

The works of [25], [26] and [27] discuss about the utility of network formations and analysis of cost and benefit of the relationship in the network. [25] characterizes the whole class of symmetric connection model, to complement the previous work done by Jackson and Wolinsky (1996) that focused on specific form of model in social network formation. The author also suggests that certain properties in utility functions could assist in identifying the importance of each property of a network formation’s utility function. In [26], one of the significant results is the utility maximizing process can have multiple stable equilibrium structures. In [27], the author presents the equilibrium of cost-benefit in social ties in a network using a modified theorem for the equilibrium forms. The varieties in cost-benefit regimes will generate different structures and various consequences of decision makings.

2.4.

Literature Review on P2P and Social Networks

This section will discuss some literatures that use and apply social network theory in P2P networks. A credit system is proposed in [7]; considering two new properties based on social networks (transferring credit and proximity of data source), to increase the cooperation among peers in a P2P network. The algorithm proposed is

(29)

proven to reduce the problems of overall balance of network and average number of hops.

Despite of our previous understanding that a P2P network is a very large and vast environment, the work of [9] proves that social network exists in a P2P network, by using and taking the theory of ‘small world’ into accountable of the research’s scope. The authors did a statistical analysis on P2P social networks that implement the social associations. Six (6) major peer social networks and original topologies were analyzed

based on some social network analysis properties (degree distribution, clustering

coefficient, average path length, betweenness and degree-degree correlations).

In [11], the authors also consider ‘small world’ theory in studying the P2P networks. This paper uses graph theory; particularly directed graph, to model the network and propose incentive mechanism using social network to develop P2P system. It applies ‘small world’ properties (consignable requests, transferable requests,

friendship rebuilding cost and distributed/local history memory) to solve P2P problems. The work of [12] will give an overview of peers’ behaviours in forming the network by applying the social network theory and using the game-theoretic approach to exploit emerging self-organized networks. The research models a self-organizing P2P network without referring any particular network, assuming that only super peer has resource-sharing information (i.e. content, bandwidth and computing power). The authors develop an analytical model to measure P2P system parameters. The formation dynamics used are individual sharing decision, internal transfer mechanism, group formation decision and interconnection formation decision.

Both works of [28] and [29] also agree that social network theory can contribute to improving the performance of a P2P system.

2.5.

Literature Review on Skype

The basic assumption in our research is based on the work of [20]. This paper also gives an overview on how Skype works, where the experiments are done to evaluate Skype functions and identify its key components. The experiment is done to

(30)

identify Skype key component (i.e. ports, host cache, codecs, buddy list, encryption

and NAT & firewalls) using Skype version 1.4.0.84 and 1.2.0.18. The observation is made on both platforms of Windows and Linux. Experiment is also done to evaluate Skype functions (i.e. startup, login, login process, user search, call establishment &

teardown, media transfer & codecs and keep-alive messages). In addition, the authors also compare Skype with other IM/Voice application (MSN, Yahoo and Google Talk).

This paper also discovers that Skype will choose super node (SN) automatically and this is unavoidable. It concludes that Skype can work even behind NAT. Skype offers higher quality compared to its competitors. Anyway, its underlying search technique for user search remains unclear. A summary on comparison of Skype with other similar applications is also included.

The work of [30] and [31] evaluate the Skype performance, whereas [32] discuss Skype accordingly to ‘small world’ theory. In [33], the authors propose gradient topology techniques to improve relay node mechanisms, which is related to the way Skype manage its peers that are located behind the NAT.

(31)

Chapter 3:

Research Model

3.1.

The Idea

Our purpose is to demonstrate that social network information could contribute to address the performance issues in P2P networks. In the scope and limitation of this work, we will focus the idea and solution on the willingness of a super node to share its resources within its contact list.

Given the current situation in the Skype network, which is described previously in Scenario I (Figure 1.5); where one of the interconnected nodes is located behind the NAT, Skype will use the super node relay approach to ensure the file transfer transaction can be done. Skype will automatically perform the super nodes selection in the network based on the accessibility of the node and the size of the bandwidth to the Internet. Anyway, to decrease the super nodes’ burden that may cause performance degradation, Skype limits the speed transaction to 5 Kb/s only.

We conduct a simple test to illustrate the implications of Scenario I. For that, we compare two (2) situations that involve file transfer using Skype; which are between (i)both PCs are located in the same public network, and (ii) one PC is located behind the NAT while the other PC is in public network (Scenario I). The size of the file transferred is approximately 360MB.

Table 3.1 presents the simple test result.

Table 3.1. Results on File Transfers

Situation Time taken (minute)

i. Both PCs are in the same public network 1.05

(32)

The transmission time for both transactions is significantly different. For the second situation of Scenario I, this is the result of the super node relay approach implementation, with the limitation of speed as well. This situation eventually will discourage file transfer activities in the Skype environment. People may transfer files with limited size, which will also contribute to a limited usage of applications too. The current architecture and implementation will give us Result A, which become the main reason that opens the opportunity and drive our motivation to do this research.

Therefore, if a user wants to transfer a large file in the Skype network, the user has to tolerate a very long transmission time, despite of using a P2P-based application. In order to address this issue, social network information will play a very important role. A successful P2P system implementation is not depending on the technology itself only, but also is depending on the users’ behaviours [16]. It is essential to understand human and social behaviours to overcome many of the performance issues in a P2P system. Social network information is a good input in assisting computer scientists in developing and deploying successful P2P systems.

The idea of our research is to gather social network information and apply the input to Scenario I. We believe by using social network information, the problem caused by Scenario I can be reduced. At the moment, super node selections are done automatically and randomly by Skype, only considering the access speed to the Internet and the accessibility of the users’ network.

Therefore, we suggest that the implementation of a P2P system will allow a node to choose its super node from its contact list. Referring to the case of Scenario I, we propose that Node A and Node B can choose their own super nodes from their contact lists (which are their social networks), rather than depending on the appointed super nodes in the Skype network.

With this new setting, the limitation of speed while doing the file transfer can be removed. This additional change will create a new setting, Scenario II. The new setting will give better transmission times, Result B.

(33)

Figure 3.1. Research Idea

In short, we are interested to see the impact of applying social network information into P2P networks. We would like to see the result by studying the currently popular Voice-over-IP (VoIP) application that uses P2P technology in its implementation: Skype.

3.2.

The Model

Consider that Node A is located in a public network while Node B is currently located in a private network. The scenario will begin with Node A, who wants to send a file to Node B. Due to the condition that Node B is located behind the NAT; the file transfer activity has to be pursued through a super node. At this point, the process will happen differently from the current model implementation.

In our research model, to which we refer to as Scenario II, Node A will choose its super node, Super Node Y from its contact list4. Node B is also choosing its super node, Super Node X from its contact list. After that Super Node X will find Super Node Y. When Super Node X acknowledges Node A about the result, Node A will establish the connection with Super Node Y directly. Node A will send the file to Node B through Super Node Y. Node B will acknowledge Super Node Y for the transaction.

4

‘Contact list’ and ‘buddy list’ will give the same interpretation throughout this work.

SKYPE SKYPE SKYPE SKYPE Result A Add Social Network Information Result B

(34)

Table 3.2 presents the summary of Scenario II.

Table 3.2. Scenario II (Summary)

1. Node A chooses a super node, which is also in its contact list, Super Node X.

2. Node B chooses a super node, which is also in its contact list, Super Node Y.

3. Super Node X finds the Super Node Y.

4. Node A sends the file to Super Node Y directly.

5. Super Node Y forwards the file to its node, Node B.

6. Node B acknowledges and receives file from Super Node Y.

7. Super Node Y acknowledges Node A.

Figure 3.2 presents the whole process of Scenario II.

Figure 3.2. Research Model

Fire wa ll /N AT Node B Node A Super Node X Private Network Super Node Y Firewall/NAT

6

5

4

3

1

7

2

(35)

For the reason that Node B is one of Super Node Y’s contact list or ‘buddy’, Super Node Y will give higher resources and priority to the file transmission. Super Node Y will allow a higher speed for the transmission. Therefore, the file transfer can be done faster, compared to the current implementation. This assumption of Scenario II is based on our research questions as discussed in Section 1.6. Moreover, we believe that “people will provide more resources for the benefit of their contacts”.

Anyway, how much a node with the higher capability is willing to be a super node and share its resources within its social network? What will make a super node to be willing to contribute and share its resources for the benefits of its contacts (social network)?

In intention to seek answers and explanation to our questions, as well as to validate our idea and research model of applying social network information into P2P systems, we will collect the related data from Skype users. In order to do so, we will use survey methodology to obtain information about users’ willingness to use our potential application. The feedbacks and inputs collected and analyzed from the survey will assist us in finding the empirical evidence to our work.

(36)

Chapter 4:

Survey and Data

4.1.

Introduction

Surveys are the most widely used methodology to gain data collection for studying user behaviour. This survey will assist us in identifying and analyzing some variables and indicators to propose our solution. In order to do so, a set of questions has been prepared to study Skype users’ behaviours and opinion towards resource sharing. The goals of the survey are:

i. to learn about the social behaviours of users that can be used to improve the resource sharing performance in a P2P environment,

ii. to examine the composition of peers in contact list (‘buddy list’ in Skype’s context), and

iii. to recognize the conditions that will motivate users with rich resources to contribute their resources (i.e. to be a super node within the Skype network). In this situation, the super nodes should be aware of their increased responsibility towards the ordinary nodes that are connected them.

The result and analysis of the survey will be used as a foundation to develop a new P2P system with social network information applied. It also can assist the P2P system development team to have preliminary evaluation on the limitation and potential of the proposed topology for future deployment.

The subject group in this interview is a population of university students of a Master program and a PhD program. We picked this group of students for the reason all of them are computer literates and use the computer frequently for communication. The set of questionnaire is distributed through e-mails. Based on the feedbacks, we analyze the answers and produce a report on key findings of the survey.

(37)

4.2.

Principle of the Survey

There are some important matters that should be considered while doing a survey. The principles we have considered in our work are:

i. Outlining the plan for the survey process. It will be significantly valuable if a survey is conducted based on certain specific goals to achieve. The predefined goals will assist us to create and include the questions that are directly addressing those goals, later to ensure the survey is processed and conducted in the right direction and accordingly to the information that we want to learn. An appropriate number of questions that could be answered in a considerable amount of time (less than 15 minutes) will be a good alternative to increase respondent participants. Besides, we should also consider some options to encourage feedbacks, including advance reminders and information to the targeted participants. The set of questionnaire should also support the later processes of analysis work and final report we wish to produce. The targeted participants should have basic knowledge to answer the questionnaire set, and to determine this, one should conduct a pilot-test with a small amount of participants. During this preliminary test, we are able to identify problems, particularly in the question wordings usage and instruction, gain early insights, and then find the appropriate remedy for the problems. This preliminary test also assists us in designing a better, flexible and easier survey format. Finally, we distributed the survey to targeted group through the emails. ii. Organize the survey design. A general explanation of the purpose of the

questionnaire, time estimated to answer the whole set and a clear instruction is given in the introductory part of the questionnaire. We also conclude the questionnaire at the end of the survey set by including a ‘thank you’ note and appreciation to the participants. The questions in the set must also arranged accordingly to the level of difficulties in answering;

(38)

simple questions will be placed at the beginning of the survey, whereas the difficult ones should be placed toward the end of the questionnaire. This is important to make the potential participants feel comfortable while answering the questionnaire set. Another important task we do in designing this survey is keeping the number of the questions discretely short and concise without neglecting the practicality of the set, in order to increase the number of the feedbacks from the population that we have selected.

iii. Questionnaire set design and construction. We construct the questions as clear as possible by writing them specifically for our intended group. The intended group of participants belongs to multiple races with different mother tongues spoken. Therefore, the usage of simple English without complex statements by omitting technical words and jargons is critical so that all participants could understand the questionnaire during the very first reading.

iv. Indicators and variables identifications. We have identified the some indicators and variables (independent and dependant) that should be tested for this survey.

4.3.

Survey Indicators and Input Variables

By referring to the definition of social networks from [5] and [6], we have identified the appropriate indicators and variables for the survey. All variables and indicators from the survey are listed in Appendix A. In this section, we will discuss the survey indicators, the dependent5 variables and the independent6 variables.

5

Dependent variable is also known as the response variable, the regressand, the measured

variable, the responding variable, the explained variable, or the outcome variable (Source:

Wikipedia, 2007).

6

Independent variable is also known as predictor variables, regressors, controlled variables,

(39)

4.3.1. Survey Indicators

We specify some variables to be the indicators for the latter analysis part. The survey indicators are used to gather inputs about application usage behaviours, functions used in Skype, group formation proportions as well as the awareness of being a super node. Table 4.1 presents the list of survey indicators.

Table 4.1. Survey Indicators

Variable ID Label and Description Question

No.

use_freq This variable is to collect data regarding Skype usage frequency among the participants. The non-Skype users are omitted from the analysis.

1

oth_app This variable is to collect data about user’s other similar applications usage. It collects input about the tendency among the users regarding other similar application usage.

2

skype_function

This variable is to collect data about the functions in Skype usually used, such as PC-to-PC call, instant messaging (IM), PCs conference, file transfer, and other functions.

3

group_perc

This variable is to collect data about the proportion of group formation in a user’s contact list, such as family member, close friends, loose contact, work acquaintances, friend of a friend and other group as well.

5

will_share This variable is to collect data about users’ proportion group

formations in their contact list. 10

sn_know This variable is to collect data about a user’s awareness of being

selected as a super node in Skype network. 9

Based on these indicators, we could verify our result in selecting the appropriate independent variables, so that we could have neat results afterwards, during modeling the multiple regression analysis.

(40)

4.3.2. Independent Variables

There are many inputs related to social network information that are potentially could be the included in our model. To this point, we try to include as many variables as we could, which are accordingly to social network theory literatures as discussed in Section 2.3 and Section 2.4. Table 4.2 will present the possible independent variables.

Table 4.2. Suggested Independent Variables

Variable_ID Label and Description Question No.

ind_view This variable is to measure user’s opinion on Skype and their

behaviour patterns. 4

buddy_list This variable is to obtain inputs about a user’s contact list size. 6

file_tran This variable is to measure the frequency of file transfer in the

general way (emails, etc.) and by using Skype. 7

size_ft This variable is to collect data about the size of files usually

transferred in general and by using Skype. 8

cond_share This variable is to measure the conditions that could encourage

any users to share their resources with their contact list. 11a-11f

super_node This variable will measure the factors of being a super node. 12a-12b,

12f-12k

These independent variables will be analyzed and tested in consequences of finding the optimum result in the following chapter.

4.3.3. Dependent Variable

The independent variables in the survey will be used to measure the dependent variable, y. The suggested dependent variable of this work is as shown in Table 4.3.

(41)

Table 4.3. Suggested Dependent Variable

Variable_ID Label and Description Question No

ds_01 This variable is to measure the users’ willingness share resources

with the people in their contact list. 12c

This variable is chosen to fit our research model and idea”. Referring to Chapter 3, we believe that users are willing to provide resources to those people that are in their contact list. Therefore, this statement can capture the needed measurement which later can be used for the regression analysis.

4.4.

Questionnaire Set

As defined in Oxford Dictionary, questionnaire is “a set of printed questions, usually with a choice of answers, devised for a survey or statistical study” which originally came from French. Questionnaire is an important tool used in many disciplines to obtain information in order to answer a research question.

In our work, the questionnaire set is designed in a simple way accordingly to the purpose of the survey: to collect information regarding the values, attitudes, beliefs, and behaviours of Skype usage among the students. It contains the combination of various formats of questions, which are:

i. Yes/No,

ii. Multiple-choice, iii. Checklists, iv. Rankings, and

v. Open-ended.

To note, 50% of the questions are with ranking format because this format is suggested as the “most easily done in written questionnaires, where respondents can see all the alternatives to be ranked and can fill in the rankings themselves” [34].

(42)

estimated to take fifteen (15) minutes to answer the whole set. The questionnaire is divided and arranged logically in order to avoid confusions among the participants. This is also to ensure the validity and consistency of the questions with the research direction.

The questions are essentially intended to assess information by grouping them accordingly to three (3) categories, which are intended to capture personal opinion towards Skype, personal file-sharing activity, and the willingness to share resources. The full set of the questionnaire is attached in Appendix B.

4.4.1. Capturing Personal Opinion towards Skype

In this part, we are interested to obtain information about personal opinions towards Skype. Therefore, we include questions to study the application usage frequency, user preference of other similar applications, Skype functions frequently used and user’s contact list.

i. Question 1. This question is to identify participant’s usage behaviour, whether the participant is a permanent user, frequent user, occasional user, infrequent user or never use Skype at all.

ii. Question 2. This question is to identify participant’s preference over similar applications to Skype. We also list down those similar applications, such as MSN Messenger, Yahoo Messenger, Gizmo, Google Talk and an open-ended answer which allow participant to write down the application that they are currently using but not enlisted in the survey.

iii. Question 3. This question requires participant to rate 1-Never, 2-Rarely, 3-Sometimes, or 4-Frequently on the Skype’s functions they usually used (PC-to-PC call, instant messaging, PCs conference, PC-to-landline/mobile call, file transfer, finding new friends and other function).

iv. Question 4. For this question, we enlist eight statements to oversee participant’s opinions towards Skype and their contact list organization.

(43)

Participants have to rate their preferences accordingly to 1-Strongly Disagree, 2-Disagree, 3-Neutral, 4-Agree, or 5-Strongly Agree.

v. Question 5. In this open-ended question, participant is required to estimate the percentage of the groups in their Skype contact list. The groups listed are family members, close friends, loose contacts, work acquaintances, people introduced by friends, and people that send invitations to be friends. Participant also could fill up their own group which is not listed in the question.

vi. Question 6. Participant is required to choose from the list about the amount of people in their Skype contact list.

4.4.2. Capturing Personal File-Sharing Activity

In this part, we are interested to obtain information about user behaviours in file-sharing activity using Skype/other medium and size of files usually transferred. For these questions, we use the rating format, divided into four category of 1-Never, 2-Rarely, 3-Sometimes, and 4-Frequently.

Question 7. This question is to collect input about file transfer frequency and type of file in general and by using Skype. We list down the most popular file formats (word document, other office-based file format, images, audio files, movie files and an open-ended answer filled up by participants) commonly transferred electronically.

Question 8. Participants are required to choose the size of the file commonly transferred electronically. The sizes range from less than 100kB to more than 100MB.

4.4.3. Capturing the Willingness to Share Resources

In this part, we are interested to obtain information about user’s level of acceptance, conditions agreed to share resources and personal opinion of being super

(44)

node. This part begins with a question to acknowledge participant’s awareness about super node selection in Skype network. The following questions are in ranking format to measure participant’s opinions towards resource sharing, with whom they are willing to share, conditions to allow resource sharing, and opinions towards being a super node.

i. Question 9. This question requires participants to answer whether they are aware about the super nodes selection or not..

ii. Question 10. This question requires participants to rate their opinion with 1-Strongly Disagree, 2-Disagree, 3-Neutral, 4-Agree, or 5-Strongly Agree, regarding resource sharing accordingly to the listed groups (family members, close friends, loose contacts, work acquaintances, people introduced by friends, people who send invitations and other group which will be listed by the participants).

iii. Question 11. We list down six conditions that we think will encourage participant to be willing of being selected as a super node in Skype network. The questions are in ranking format, divided into 3 categories of 1-Unimportant, 2-Neutral, and 3-Important.

iv. Question 12. For this section, we list down ten statements that require the participant to rate their opinion with 1-Strongly Disagree, 2-Disagree, 3-Neutral, 4-Agree, and 5-Strongly Agree accordingly.

(45)

Chapter 5:

Analysis and Result

5.1.

Introduction

In commencement of this chapter, we would like to reemphasize our goals and attentions in pursuing our work, which are to:

i. address the performance issues in a P2P system,

ii. validate our idea and model of enhancing a P2P system with social

network information,

iii. provide evidence that “people are willing to provide more resources for the benefit of their contact (‘buddies’)” in at least one (1) condition which is later described in Section 5.3,

iv. analyze the inputs and their consequences in identifying the related cases to include into the outputs, and

v. to use the outputs from the analysis to propose a framework in developing a P2P system with social network applied.

The descriptive analysis is used to evaluate the subject population and the feedbacks received from the survey. At the same time, the analysis will be the foundation to select the right independent variables for our model. The multiple regression analysis will be used in identifying the factors that will affect users’ willingness to share their resources in a P2P network.

This chapter will begin with the survey feedbacks, descriptive analysis to discuss the significant of our chosen variables for the multiple regression analysis, followed by the regression analysis model, result and the key findings discussion.

5.2.

Survey Feedbacks

As concluded in [35], a data set is composed of information from a set of units and the information from a unit is known as an observation. An observation consists of

(46)

one or more pieces of information about the unit; these are called variables. A feedback is considered an observation. We receive 60 observations7, which is a good rate of responses, considering the overall total of the potential numbers of participants in the targeted group.

5.3.

Descriptive Analysis

This section will discuss the descriptive analysis on the data obtained from the survey. In particular, we perform a descriptive analysis about users’ sophistication in using online communication applications, personal opinions towards Skype, file transfer activity using Skype, awareness about the super nodes selection, resource sharing willingness, conditions to be a super node, and finally important factors in being a super node.

This section is very important for it will be the criteria to determine the independent variables for the multiple regression analysis, as well as will be used to answer some of our research questions.

5.3.1. Analysis on Users Sophistication in Using Online Communication Applications

This section will evaluate and summarize the sophistication of the users in using the online communication applications such as Skype, MSN Messenger, Yahoo Messenger or Google Talk. Even though our focus will be solely on Skype, it is within our interest coverage to see the behaviour patterns among the users while using the various online communication applications concurrently with Skype.

5.3.1.1 Skype Usage Frequency

In the questionnaire set, we are interested to overview the behaviour patterns among the targeted group in using Skype. For the first question, the answers are categorized into five (5), which are permanent, frequent, occasional infrequent and

7

(47)

never use. From the observations received, we compare the result for each answer and summarize the result in percentage. Figure 5.1 presents the chart of the percentage analysis. Never Infrequent Occasional Frequent Permanent 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 N o. o f Observat ions 11.67% 16.67% 23.33% 23.33% 25.0%

Figure 5.1. Skype Usage Frequency Analysis

As we may conclude, 83.3% from the observations are using Skype and the remainder of 16.67% belongs to the non-Skype users. Next, we omit the non-Skype users from our following analysis, and the evaluation is done on the remainder of fifty (50) observations.

5.3.1.2 Similar Applications Usage Frequency

The second question in the survey is intended to see the patterns of application usage among the Skype users only. The result shows only 2% of the observations are using Skype only, and 98% of the Skype users are also using other similar applications. Our preliminary overview shows that none of the observations are using Gizmo. Thus, we exclude Gizmo from our analysis.

From the 98% of the Skype users, 22.49% are using MSN only, 14.29% are using Yahoo Messenger (YM) only and 4.08% are using Google Talk (GT) only. A

References

Related documents

Pertaining to the secondary hypothesis, part 1, whether citalopram administration could raise ACTH levels in both alcohol-dependent patients and controls, no significant

They would not only become aware of their own inner strengths and characteristics (Seligman et al., 2009), but they would also feel the use of true partnership of the family

It was decided that with the presence of such significant red flag signs that she should undergo advanced imaging, in this case an MRI, that revealed an underlying malignancy, which

Final game project classes give students a more holistic view of computer science and teach or reinforce a variety of skills, including computational thinking skills, software

The use of sodium polyacrylate in concrete as a super absorbent polymer has promising potential to increase numerous concrete properties, including concrete

The user submits each Highway Conveyance Document through the Portal (see Appendix 1 for required data elements). Prior to submission, the Portal automatically checks syntax to

The personal development ethos is supported by a wide range of training courses offered by Glanbia – management training course and accounting courses are just some of

through RANSAC algorithm; ( lower left ) detection of the non-occluded parts of the tomato, ω i t + 1 , through region growing algorithm; ( lower right ) initialization of the