Game Theory in Communications:a Study of Two Scenarios

Multi-user communication theory typically studies the fundamental limits of communication systems, and considers communication schemes that approach or even achieve these limits. The functioning of many such schemes assumes that users always cooperate, even when it is not in their own best interest. In practice, this assumption need not be fulfilled, as rational communication participants are often only interested in maximizing their own communication experience, and may behave in an undesirable manner from the system's point of view. Thus, communication systems may operate differently than intended if the behavior of individual participants is not taken into account. In this thesis, we study how users make decisions in wireless settings, by considering their preferences and how they interact with each other. We investigate whether the outcomes of their decisions are desirable, and, if not, what can be done to improve them. In particular, we focus on two related issues. The first is the decision-making of communication users in the absence of any central authority, which we consider in the context of the Gaussian multiple access channel. The second is the pricing of wireless resources, which we consider in the context of the competition of wireless service providers for users who are not contractually tied to any provider, but free to choose the one offering the best tradeoff of parameters. In the first part of the thesis, we model the interaction of self-interested users in a Gaussian multiple access channel using non-cooperative game theory. We demonstrate that the lack of infrastructure leads to an inefficient outcome for users who interact only once, specifically due to the lack of coordination between users. Using evolutionary game theory, we show that this inefficient outcome would also arise as a result of repeated interaction of many individuals over time. On the other hand, if the users correlate their decoding schedule with the outcome of some publicly observed (pseudo) random variable, the resulting outcome is efficient. This shows that sometimes it takes very little intervention on the part of the system planner to make sure that users choose a desirable operating point. In the second part of the thesis, we consider the competition of wireless service providers for users who are free to choose their service provider based on their channel parameters and the resource price. We model this situation as a two-stage game where the providers announce unit resource prices in the first stage and the users choose how much resource they want to purchase from each provider in the second stage. Under fairly general conditions, we show that the competitive interaction of users and providers results in socially optimal resource allocation. We also provide a decentralized primal-dual algorithm and prove its convergence to the socially optimal outcome

Wireless Sensor Networks

The aim of this book is to present few important issues of WSNs, from the application, design and technology points of view. The book highlights power efficient design issues related to wireless sensor networks, the existing WSN applications, and discusses the research efforts being undertaken in this field which put the reader in good pace to be able to understand more advanced research and make a contribution in this field for themselves. It is believed that this book serves as a comprehensive reference for graduate and undergraduate senior students who seek to learn latest development in wireless sensor networks

Assessing the readiness of public healthcare facilities to adopt health information technology (hit)/e-health: a case study of Komfo Anokye Teaching Hospital, Ghana

Most health information technology (HIT)/e-Health initiatives in developing countries are still in project phases and few have become part of routine healthcare delivery due to the lack of clear implementation roadmap. Ghana has been piloting a number of e-Health initiatives, which have not guaranteed a sustainable implementation of such systems. The objective of this research study was to explore the information technology (IT) readiness of public healthcare institutions (primary, secondary and tertiary) in Ghana to adopt e-Health in order to develop a standard HIT/e-Health readiness assessment model. For a population of 28,678,251 people there are only 2,615 medical doctors on the Ministry of Health’s (MoH) payroll as at 2013 and 1818 public hospitals. Consequently, the doctor to population ratio is extremely low as compared to other developing countries, which falls far below the WHO revised standard of 1:600. Under these circumstances there is evidence in developed countries that adoption of health informatics technologies can contribute to improving the situation. An extensive review of literature on e-health in developing countries has identified a general lack of adoption due to a lack of readiness to incorporate the technology into the healthcare environment. Literature provides myriad but fragmented models/frameworks of health information technology (HIT)/e-Health adoption readiness assessment limited measuring tools to assess factors of HIT readiness. This risks the outcomes of HIT/e-Health readiness assessment, which eventually limits knowledge about the strategic gaps warranting the need for the implementation of HIT/e-Health systems in public healthcare institutions in Ghana. Whiles previous studies acknowledge the existence of HIT readiness assessment factors, there exist very limited measuring items for these factors. Simply put, there is not just limited studies on HIT readiness assessment, but there is also no standard guiding readiness assessment model. This study has identified the lack of standard assessment model/framework as well as their accompanying measuring tools for effective outcomes as major gaps. Thus, there was the need for gaining a deeper understanding of existing readiness factors and their applicability in the context of the readiness of public healthcare facilities in Ghana and how they promote or impede HIT/e-Health adoption in order to develop standard HIT readiness assessment model, which comprises readiness factors and most importantly their measuring tools. This study used a mixed method approach, specifically the exploratory sequential design (the exploratory design) where the outcome of qualitative data collected from 13 senior health CIOs and leaders of e-Health initiatives in Ghana analysed built to quantitative data collection instrument. The survey instrument was used to collect quantitative data from 298 clinical and non-clinical staff (Administration/Management leadership) Komfo Anokye Teaching Hospital (KATH) in a form of case study to confirm the findings of the initial exploratory study. This was because the mixed method is rooted in the pragmatism of philosophical assumptions, which guide the direction of the collection and analysis of data and the mixture of qualitative and quantitative approaches in many phases of the research process. Furthermore, mixed research methods design strategy provides a powerful mechanism for IS researchers in dealing with the rapidly changing environment of ICT. An initial standard regression analysis using IBM SPSS version 23 established that five factors (Technology readiness (TR); Operational resource readiness (ORR); Organizational cultural readiness (OCR); Regulatory policy readiness (RPR); and Core readiness (CR)) and 63 indicators (measuring tools) promote and/or impede HIT/e-Health adoption readiness in public healthcare facilities in Ghana. Consequently, these factors were used in developing a standard HIT readiness assessment model. Whiles these five factors all proved to have strong association with the dependent variable Health Information Technology readiness (HITR) in the standard regression, (R2 = 0.971) the findings of a latter PLS-SEM, an advanced regression analysis deployed suggest that Regulatory policy readiness (RPR) and remarkably Core readiness (CR) did not impact on the readiness of KATH to adopt e-Health/HIT. As many public healthcare organizations in Ghana have already begun the process of implementing various HIT/e-Health systems without any reliable HIT/e-Health regulatory policy in place, there is a critical need for reliable HIT/e-Health regulatory policies (RPR) and some improvement in HIT/e-Health strategic planning (core readiness). The final model (R2 = 0.558 and Q2= 0.378) suggest that TR, ORR, and OCR explained 55.8% of the total amount of variance in health information technology/e-Health readiness in the case of KATH, partially supporting the hypotheses of this study. Although no formal hypotheses were proposed for the relationships/effects, which exist between exogenous/independent constructs in the model structure, the SmartPLS3 model path analysis did show that there exist such relationships. For instance, the significant paths from regulatory policy readiness (RPR) to organizational resource readiness (ORR) (t = 23.891; Beta = 0.774) and from technological readiness (TR) to operational resource readiness (ORR) (t = 11.667; Beta = 0.624) obtained from SmartPLS3 bootstrap procedure indicate the presence of mediation. Fit values (SRMR = 0.054; NFI = 0.739). Generally, the GoF for this SEM are encouraging and can substantially be improved when public healthcare facilities in Ghana intending to implement HIT/e-Health pay equal attention to relevant regulatory policies and strategic planning. The readiness assessment model developed this study essentially offers a useful basis for healthcare organizations to enhance the conditions under which HIT/eHealth is launched in order to achieve successful and sustainable adoption with particularly attention being paid to HIT/e-Health regulatory policies and strategic planning. When evaluations such as this are carried out effectively, there could be a circumvention of large losses in money effort and time, delays and disappointments among planners, staff and users of services whiles facilitating the process of change in the institutions and communities involved. This study was conducted with selected subjects and selected public healthcare facilities in the southern cities/parts of Ghana. Therefore, a replication or transfer of this study to other parts of Ghana especially the rural areas and the private healthcare environment should consider the potential differences resulting from varying cultural, socioeconomic and political backgrounds since healthcare is a much-institutionalised industry. The same caution must be exercise when replicating this study in other developing countries and across the globe

Assessing the readiness of public healthcare facilities to adopt health information technology (hit)/e-health: a case study of Komfo Anokye Teaching Hospital, Ghana

Most health information technology (HIT)/e-Health initiatives in developing countries are still in project phases and few have become part of routine healthcare delivery due to the lack of clear implementation roadmap. Ghana has been piloting a number of e-Health initiatives, which have not guaranteed a sustainable implementation of such systems. The objective of this research study was to explore the information technology (IT) readiness of public healthcare institutions (primary, secondary and tertiary) in Ghana to adopt e-Health in order to develop a standard HIT/e-Health readiness assessment model. For a population of 28,678,251 people there are only 2,615 medical doctors on the Ministry of Health’s (MoH) payroll as at 2013 and 1818 public hospitals. Consequently, the doctor to population ratio is extremely low as compared to other developing countries, which falls far below the WHO revised standard of 1:600. Under these circumstances there is evidence in developed countries that adoption of health informatics technologies can contribute to improving the situation. An extensive review of literature on e-health in developing countries has identified a general lack of adoption due to a lack of readiness to incorporate the technology into the healthcare environment. Literature provides myriad but fragmented models/frameworks of health information technology (HIT)/e-Health adoption readiness assessment limited measuring tools to assess factors of HIT readiness. This risks the outcomes of HIT/e-Health readiness assessment, which eventually limits knowledge about the strategic gaps warranting the need for the implementation of HIT/e-Health systems in public healthcare institutions in Ghana. Whiles previous studies acknowledge the existence of HIT readiness assessment factors, there exist very limited measuring items for these factors. Simply put, there is not just limited studies on HIT readiness assessment, but there is also no standard guiding readiness assessment model. This study has identified the lack of standard assessment model/framework as well as their accompanying measuring tools for effective outcomes as major gaps. Thus, there was the need for gaining a deeper understanding of existing readiness factors and their applicability in the context of the readiness of public healthcare facilities in Ghana and how they promote or impede HIT/e-Health adoption in order to develop standard HIT readiness assessment model, which comprises readiness factors and most importantly their measuring tools. This study used a mixed method approach, specifically the exploratory sequential design (the exploratory design) where the outcome of qualitative data collected from 13 senior health CIOs and leaders of e-Health initiatives in Ghana analysed built to quantitative data collection instrument. The survey instrument was used to collect quantitative data from 298 clinical and non-clinical staff (Administration/Management leadership) Komfo Anokye Teaching Hospital (KATH) in a form of case study to confirm the findings of the initial exploratory study. This was because the mixed method is rooted in the pragmatism of philosophical assumptions, which guide the direction of the collection and analysis of data and the mixture of qualitative and quantitative approaches in many phases of the research process. Furthermore, mixed research methods design strategy provides a powerful mechanism for IS researchers in dealing with the rapidly changing environment of ICT. An initial standard regression analysis using IBM SPSS version 23 established that five factors (Technology readiness (TR); Operational resource readiness (ORR); Organizational cultural readiness (OCR); Regulatory policy readiness (RPR); and Core readiness (CR)) and 63 indicators (measuring tools) promote and/or impede HIT/e-Health adoption readiness in public healthcare facilities in Ghana. Consequently, these factors were used in developing a standard HIT readiness assessment model. Whiles these five factors all proved to have strong association with the dependent variable Health Information Technology readiness (HITR) in the standard regression, (R2 = 0.971) the findings of a latter PLS-SEM, an advanced regression analysis deployed suggest that Regulatory policy readiness (RPR) and remarkably Core readiness (CR) did not impact on the readiness of KATH to adopt e-Health/HIT. As many public healthcare organizations in Ghana have already begun the process of implementing various HIT/e-Health systems without any reliable HIT/e-Health regulatory policy in place, there is a critical need for reliable HIT/e-Health regulatory policies (RPR) and some improvement in HIT/e-Health strategic planning (core readiness). The final model (R2 = 0.558 and Q2= 0.378) suggest that TR, ORR, and OCR explained 55.8% of the total amount of variance in health information technology/e-Health readiness in the case of KATH, partially supporting the hypotheses of this study. Although no formal hypotheses were proposed for the relationships/effects, which exist between exogenous/independent constructs in the model structure, the SmartPLS3 model path analysis did show that there exist such relationships. For instance, the significant paths from regulatory policy readiness (RPR) to organizational resource readiness (ORR) (t = 23.891; Beta = 0.774) and from technological readiness (TR) to operational resource readiness (ORR) (t = 11.667; Beta = 0.624) obtained from SmartPLS3 bootstrap procedure indicate the presence of mediation. Fit values (SRMR = 0.054; NFI = 0.739). Generally, the GoF for this SEM are encouraging and can substantially be improved when public healthcare facilities in Ghana intending to implement HIT/e-Health pay equal attention to relevant regulatory policies and strategic planning. The readiness assessment model developed this study essentially offers a useful basis for healthcare organizations to enhance the conditions under which HIT/eHealth is launched in order to achieve successful and sustainable adoption with particularly attention being paid to HIT/e-Health regulatory policies and strategic planning. When evaluations such as this are carried out effectively, there could be a circumvention of large losses in money effort and time, delays and disappointments among planners, staff and users of services whiles facilitating the process of change in the institutions and communities involved. This study was conducted with selected subjects and selected public healthcare facilities in the southern cities/parts of Ghana. Therefore, a replication or transfer of this study to other parts of Ghana especially the rural areas and the private healthcare environment should consider the potential differences resulting from varying cultural, socioeconomic and political backgrounds since healthcare is a much-institutionalised industry. The same caution must be exercise when replicating this study in other developing countries and across the globe

Network-aware video streaming for future media Internet

272 p

MIMO-based Friendly Jamming and Interference Management Techniques for Secure Wireless Communications

The ever-increasing growth of wireless systems has made them an essential part of our daily life. People rely heavily on wireless networks for communications and to conduct critical transactions from their mobile devices, including financial transactions, access to health records, etc. The proliferation of wireless communication devices opens the door for many security breaches, ranging from eavesdropping to jamming attacks. Such a disadvantage stems from the broadcast nature of wireless transmissions, which creates an exposed environment. In this dissertation, we focus on eavesdropping attacks. While cryptographic techniques can be used to thwart eavesdropping attacks and enable secure wireless communications, they are not sufficient to protect the lower-layer headers of a packet (i.e., PHY and MAC headers). Hence, even though the secret message is encrypted, these unencrypted headers can be exploited by an adversary to extract invaluable information and initiate malicious attacks (e.g., traffic classification). Physical-layer (PHY-layer) security has been introduced as a promising candidate to prevent attacks that exploit unencrypted lower layer headers. PHY-layer security techniques typically rely on injecting an intentional interference into the medium so as to confuse nearby eavesdroppers (Eve). Specifically, a legitimate transmit-receive (Alice-Bob) pair generates a bogus signal, namely friendly jamming (FJ), along with the information signal, to increase interference at Eve(s) but without affecting the legitimate receiver (Bob). Depending on which end of a legitimate link is responsible for generating the FJ signal, two types of FJ techniques exist: transmitter-based (TxFJ) and receiver-based (RxFJ). In this dissertation, we propose to advance the state-of-art in PHY-layer security by considering multi-link scenarios, including multi-user multiple-input multiple-output (MU-MIMO) and peer-to-peer (P2P) networks. Specifically, we consider a scenario where one or more external Eve(s) attempt to snoop on communications of various links. In such networks, transmission of one link may be interfered with neighboring links' transmissions. Thus, special care must be dedicated to handling interference. In our first contribution in this dissertation, we consider a P2P network tapped by external Eve(s) in which each Alice-Bob pair conceals its communications using TxFJ. TxFJ is realized at Alice side using MIMO precoding. The goal is to design the precoders for both information and TxFJ signals at all Alices so as to maximize a given utility (e.g., sum of communication rates) while preventing eavesdropping elsewhere. Because legitimate links do not cooperate with each other and there is no centralized authority to perform optimization, every link selfishly aims at maximizing its secrecy rate. Using non-cooperative game theory, we design a distributed method for maximizing the sum of secrecy rates. Under the exact knowledge of eavesdropping channels, we show that our distributed method has a comparable secrecy sum-rate to a centralized approach. In our next contribution, we focus on employing practical precoders in our design for a P2P network. Specifically, we employed a zero-forcing-based (ZF-based) precoder for the TxFJ of each Alice-Bob pair in a P2P network. We also assume that each link has a certain rate demand to be satisfied. In such a scenario, even though the non-cooperative game designed for this P2P network is shown to be convergent to its unique Nash Equilibrium (NE), there is still no guarantee that the resulting NE is Pareto-optimal. Hence, we propose a modified price-based game, in which each link is penalized for generating interference on other legitimate links. We show that the price-based game converges to the Pareto-optimal point of secrecy rate region. We then leverage mixed-strategy games to provide solutions that are robust to uncertainties in knowledge of eavesdropping channels. The proposed ZF-based design of precoders is also implemented on software-defined radios to assess its performance on a single link in real-world scenarios. In another contribution of this dissertation, we consider to further enhance the secrecy of each link in a P2P network by equipping each receiver with RxFJ. Hence, in addition to the power allocation between TxFJ and information signals, we optimize RxFJ power as well. We show that by using RxFJ at each Bob, we could leverage the well-established concept of concave games, which compared to non-convex games enjoy more simplified game-theoretic analysis. We derive sufficient conditions under which the game admits a unique NE. We also propose another version of our power control algorithm that can be implemented asynchronously, making it robust to transmission delays in the network. In our last contribution, we consider the downlink of a MU-MIMO network in the presence of an external Eve. No knowledge of Eve's location is assumed at the access point. The network is studied in underloaded and overloaded conditions. In an underloaded (overloaded) network, the number of antennas at the access point is larger (smaller) than the total number of downlink users' antennas. In the overloaded setting, traditional methods of creating TxFJ, such as ZF-based methods, are infeasible. We propose a linear precoding scheme that relaxes such infeasibility in overloaded MU-MIMO networks. In the worst-case scenario where Eve has knowledge of the channels between access point and downlink users, we show that our method imposes the most stringent condition on the number of antennas required at Eve to cancel out TxFJ signals. We also show that choosing the number of independent streams to be sent to downlink users has an important role in achieving a tradeoff between security, reliability, and the achievable rate

JTIT

kwartalni

SPATIAL TRANSFORMATION PATTERN DUE TO COMMERCIAL ACTIVITY IN KAMPONG HOUSE

ABSTRACT Kampung houses are houses in kampung area of the city. Kampung House oftenly transformed into others use as urban dynamics. One of the transfomation is related to the commercial activities addition by the house owner. It make house with full private space become into mixused house with more public spaces or completely changed into full public commercial building. This study investigate the spatial transformation pattern of the kampung houses due to their commercial activities addition. Site observations, interviews and questionnaires were performed to study the spatial transformation. This study found that in kampung houses, the spatial transformation pattern was depend on type of commercial activities and owner perceptions, and there are several steps of the spatial transformation related the commercial activity addition. Keywords: spatial transformation pattern; commercial activity; owner perception, kampung house; adaptabilit