The frequency spectrum allocated to cellular mobile telephone systems is very limited. Efficient channel assignment schemes can significantly increase the utilization of the available frequency channels. Virtually Fixed Channel Assignment (VFCA) is a dynamic channel assignment method. The idea behind it is simple: each cell is allocated a set of nominal channels. A call request generated in a cell is assigned a nominal channel if one is available. Otherwise, a channel from an adjacent cell is borrowed to serve this call as long as frequency interference constraints are satisfied. VFCA is a promising method because (i) it is efficient in channel assignment, and (ii) it is relatively easy to implement compared to other dynamic channel assignment methods. VFCA has been analyzed based primarily on simulation studies in the past twenty years. In this thesis, we focus our study on development of new channel borrowing strategies and analytical models for VFCA. The contribution of this work is summarized as follows. (1) Development of an queuing model for performance analysis of VFCA. This model may also be used to conduct sensitivity analysis on some system parameters when VFCA is used. (2) Proposed a new channel reservation scheme for handoffs. (In a cellular system, when a call using a channel crosses a cell boundary, it needs to be handed off to a new channel in the new cell. This is called a handoff.) An optimization model for this channel reservation scheme is developed. (3) Applied the fluid-flow approach to modeling an integrated mobile cellular system that uses VFCA to estimate the distribution of data queue length in a cell of the system. These results are useful in the design, performance analysis and optimization of VFCA schemes.

台灣目前行動電話市場已趨向飽和，所以已經擁有了高普及率，那麼高使用率就是下一階段該努力的方向。而加值服務就是促使高使用量的關鍵。 加值服務讓行動電話從「耳朵的時代」轉變成「眼睛的時代」，不再只是接打電話的工具，而是可以下載電影、聽音樂，甚至行動電話不再是工具，而是個人代表。 行動商務的運用需要三個條件。基礎建設的創新、加值服務的應用與手持式裝置的成熟。基礎建設的創新是要讓無線網路的技術穩定、快速且全面無死角，才有辦法談到後續的加值服務。其次是加值服務的應用，加值服務的應用不需贅言，他會是加值應用服務的核心，其必須滿足使用者的需求才有意義。最後則是手持式裝置的成熟，其中包括顯示方式、大小及格式相容等問題。 在強調以人為本的現代社會，行動電話也將從人出發，滿足使用者的需求。所以Mobile 2.0就這樣出現。 所以本研究將以Mobile 2.0概念出發，研究未來行動商務的應用和可能發展的硬體裝置。 / The mobile communication market in Taiwan has reached saturation with cell phones being readily accessible. The focus for future development hence points to increasing the usage of such communication devices, and the key lies in the introduction of accessorial services. These accessorial services allowed telecommunication to evolve from the “age of hearing” to the “age of visualization”. Communication devices no longer serve to simply communicate, but also to download movies and to listen to music. They are no longer used as tools, but as a representation of the user. There are three factors involved in the application of telecommunication in business: infrastructure, accessorial services, and hardware installation. A well-established infrastructure involves a stable, efficient, and well-covered wireless network and enables the use of accessorial services. The application of accessorial services must fulfill the customer's needs. In addition, the installation of hardware must be well developed to be fully compatible between differences in size, graphics, formats, etc. With the modern society taking the idea of individualism as the center, communication devices will do the same to fulfill users' demands. This is the idea behind "Mobile 2.0." The study is based on the ideas of Mobile 2.0 to study future business applications and hardware accessories.

Our increasing reliance on mobile devices has given rise to a new class of software applications (i.e., mobile apps). Tens of thousands of developers have developed hundreds of thousands of mobile apps that are available across multiple platforms. These apps are used by millions of people around the world every day. However, most software engineering research has been performed on large desktop or server applications. We believe that research efforts must begin to examine mobile apps. Mobile apps are rapidly growing, yet they differ from traditionally-studied desktop/server applications. In this thesis, we examine such apps by performing three quantitative studies. First, we study differences in the size of the code bases and development teams of desktop/server applications and mobile apps. We then study differences in the code, dependency and churn properties of mobile apps from two different mobile platforms. Finally, we study the impact of size, coupling, cohesion and code reuse on the quality of mobile apps. Some of the most notable findings are that mobile apps are much smaller than traditionally-studied desktop/server applications and that most mobile apps tend to be developed by only one or two developers. Mobile app developers tend to rely heavily on functionality provided by the underlying mobile platform through platform-specific APIs. We find that Android app developers tend to rely on the Android platform more than BlackBerry app developers rely on the BlackBerry platform. We also find that defects in Android apps tend to be concentrated in a small number of files and that files that depend on the Android platform tend to have more defects. Our results indicate that major differences exist between mobile apps and traditionally-studied desktop/server applications. However, the mobile apps of two different mobile platforms also differ. Further, our results suggest that mobile app developers should avoid excessive platform dependencies and focus their testing efforts on source code files that rely heavily on the underlying mobile platform. Given the widespread use of mobile apps and the lack of research surrounding these apps, we believe that our results will have significant impact on software engineering research. / Thesis (Master, Computing) -- Queen's University, 2013-01-24 10:15:56.086

Mobile service provisioning is intended to serve interoperable functionality from mobile devices over the network. The mobile service paradigm shifts the role of mobile devices from consumers to providers, opening up new opportunities for a multitude of collaborative services and applications ranging from sharing personal information to collaborative participatory sensing. Although many basic principles of the standard Web service approach continue to apply, the inherent limitations of mobile devices and broadband wireless access render the deployment of standard architectures in mobile environments inefficient. This research introduces two concepts that revolutionize mobile service provisioning: personal and cloud-assisted service provisioning. Personal services are intended to offer a range of user-centric data services to a limited set of consumers that are explicitly authorized by the user providing the service. Personal services facilitate prevailing trends such as social networking and mobile healthcare services, without compromising personal privacy. Cloud-assisted service provisioning bridges the gap between limited resources of mobile devices and increasing resource demands of mobile applications. This approach provides reliable and efficient mobile services, while alleviating the burden on limited mobile resources. Both approaches take advantage of the device's mobility and real time access to various context information. Experimental results reveal that personal services offer personalization based on the user's context and preferences, while cloud-assisted service provisioning, in addition to optimizing the consumption of mobile scarce resources, offers significant improvement to the reliability and availability of mobile services. / Thesis (Ph.D, Computing) -- Queen's University, 2013-09-03 10:28:42.795

We extend the Jinni mobile agent architecture with a multicast network transport layer, an agent-to-agent delegation mechanism and a reflection based Prolog-to-Java interface. To ensure that our agent infrastructure runs efficiently, independently of router-level multicast support, we describe a blackboard based algorithm for locating a randomly roaming agent. As part of the agent-to-agent delegation mechanism, we describe an alternative to code-fetching mechanism for stronger mobility of mobile agents with less network overhead. In the context of direct and reflection based extension mechanisms for Jinni, we describe the design and the implementation of a reflection based Prolog-to-Java interface. The presence of subtyping and method overloading makes finding the most specific method corresponding to a Prolog call pattern fairly difficult. We describe a run-time algorithm which provides accurate handling of overloaded methods beyond Java's reflection package's limitations.

The purpose of this thesis is to present a comprehensive colligation of applications of mobile agents in networks, and provide a baseline association of these systems. This work has been motivated by the fact that mobile agent systems have been deemed proficuous alternatives in system applications. Several mobile agent systems have been developed to provide scalable and cogent solutions in network-centric applications. This thesis examines some existing mobile agent systems in core networking areas, in particular, those of network and resource management, routing, and the provision of fault tolerance and security. The inherent features of these systems are discussed with respect to their specific functionalities. The applicability and efficacy of mobile agents are further considered in the specific areas mentioned above. Although an initial foray into a collation of this nature, the goal of this annotated bibliography is to provide a generic referential view of mobile agent systems in network applications.

The fusion of computers and communications has promised to herald the age of information super-highway over high speed communication networks where the ultimate goal is to enable a multitude of users at any place, access information from anywhere and at any time. This, in a nutshell, is the goal envisioned by the Personal Communication Services (PCS) and Xerox's ubiquitous computing. In view of the remarkable growth of the mobile communication users in the last few years, the radio frequency spectrum allocated by the FCC (Federal Communications Commission) to this service is still very limited and the usable bandwidth is by far much less than the expected demand, particularly in view of the emergence of the next generation wireless multimedia applications like video-on-demand, WWW browsing, traveler information systems etc. Proper management of available spectrum is necessary not only to accommodate these high bandwidth applications, but also to alleviate problems due to sudden explosion of traffic in so called hot cells. In this dissertation, we have developed simple load balancing techniques to cope with the problem of tele-traffic overloads in one or more hot cells in the system. The objective is to ease out the high channel demand in hot cells by borrowing channels from suitable cold cells and by proper assignment (or, re-assignment) of the channels among the users. We also investigate possible ways of improving system capacity by rescheduling bandwidth in case of wireless multimedia traffic. In our proposed scheme, traffic using multiple channels releases one or more channels to increase the carried traffic or throughput in the system. Two orthogonal QoS parameters, called carried traffic and bandwidth degradation, are identified and a cost function describing the total revenue earned by the system from a bandwidth degradation and call admission policy, is formulated. A channel sharing scheme is proposed for co-existing real-time and non-real-time traffic and analyzed using a Markov modulated Poisson process (MMPP) based queueing model. The location management problem in mobile computing deals with the problem of a combined management of location updates and paging in the network, both of which consume scarce network resources like bandwidth, CPU cycles etc. An easily implementable location update scheme is developed which considers per-user mobility pattern on top of the conventional location area based approach and computes an update strategy for each user by minimizing the average location management cost. The cost optimization problem is elegantly solved using a genetic algorithm.

An increasing number of technologies and applications have begun to focus on mobile computing and the wireless Web as a way to conduct commerce-oriented transactions. M-commerce Websites that are usability friendly must emphasize information quality, system quality, and service quality, as these are proxy measures to mobile commerce user satisfaction (MCUS). Measureable variables can help researchers to understand how satisfaction induces users to return to a Website. Although several studies on m-commerce user satisfaction focus on content quality, appearance, service quality, and ease of use, the results of these studies were inconclusive because they do not address contextual usability barriers for the mobile Web. The task context, which consist of two activities, search and transaction, is a prominent contextual factor that affects mobile usability positively or negatively in achieving MCUS. The researcher determined what end user expectations and actual usage beliefs result in disconfirmation or MCUS. An empirical field study of an online retailer and search platform was conducted using a sampling of 98 participants. The participants used a smartphone to search and complete a transaction in the participant's natural setting. The study results indicated that expectations and usability measures including efficiency, errors, and flexibility significantly influence actual usage leading to MCUS. The original Expectation Confirmation Theory (ECT) model assumed that user's expectations could lead to actual usage. However, in the modified ECT model, it is the actual usage experience itself that determines MCUS. Disconfirmation is an inconsistent measure tied to actual usage, purchase intent, or satisfaction as mobile users often make purchases from m-commerce Websites because of convenience, flexibility, efficiency, and accessibility. If the user experiences an error during the search or transaction activity, such a drawback can cost a mobile Website future traffic, the loss of a transaction, and lead to lower levels of satisfaction.

Crowdsourcing is the outsourcing of a job or task to a large group of individuals. Crowdsourcing has emerged from the concepts of Outsourcing, Open Source Software (OSS) Collaboration, Open Innovation, and User Innovation. While Crowdsourcing has provided an innovative way in which work can be outsourced to a large group of people, the advent of Mobile Telephony in Africa has provided a whole new dimension. This is the merging of the concepts of Crowdsourcing and Mobile Telephony, to form Mobile Crowdsourcing. Mobile Crowdsourcing has the potential to contribute significantly to the use of Information Technology (IT) in developing countries by providing a platform that would enable people such as those in peri-urban Kenyan communities, to utilise their mobile handsets to perform a set of mobile-based tasks. Payment for these tasks is made possible through mobile money platforms such as “M-Pesa”. Such innovation could provide a means for social empowerment for many of these unemployed technology users. This study sets forth to examine a set of factors that are likely to predict the “participation intention” of peri-urban Kenyan youths in Mobile Crowdsourcing. Motivational Theory, and the Theory of Reasoned Action (TRA) form the core of the theoretical framework used for this study. The McKnight Model is used as a supporting theory, to examine “trusting beliefs”. In addition, the constructs “perceived credibility”, “social influence” and “community identification” are derived from prior studies that use Socio Cognitive Theory and an extended version of the Technology Acceptance Model (TAM). These also play a supporting role. Using a survey instrument, data was collected from peri-urban youths in four peri-urban communities, and 279 usable responses were obtained for this study. Findings show that “self-development”, “integrity”, and “reputation” are the most significant predictors of “participation intention”. These three variables account for 17% of the variance in “participation intention”. Contrary to suggestions made in prior literature on Crowdsourcing, “monetary compensation” was not found to be a key motivator. This finding will no doubt spark future debate as to the role money plays in Crowdsourcing, especially in Africa. Additional findings show that “attitude” was found to be a strong mediator of the relationship between “technology anxiety” and “participation intention”. Moreover, “community identification” was found to be a full moderator of the relationship between “social influence” and “participation intention”. Findings made uncovered new insights about the perceptions and attitudes of mobile phone users in developing countries. Contributions made to theory and practice are also discussed.

Thesis advisor: S. Anukriti / Since the launch of M-PESA in 2007, mobile money has created the potential to increase financial inclusion by providing a safe and convenient place to store wealth. This paper analyzes the impact of mobile money on savings practices in Sub-Saharan Africa. Using 2015 survey data from Uganda, Kenya, and Tanzania, I find that mobile money account holders are 10.9 percent more likely to save than non-account holders, holding constant other characteristics. Mobile money has a positive and significant impact on saving for daily consumption, for protection against income shocks, and for business and education investments. In addition, I find that mobile money is a complement to formal savings (bank accounts) and a substitute for informal savings. By increasing saving, mobile money better enables individuals to rely on savings in the event of a negative income shock. These results are consistent with a policy agenda that promotes financial inclusion by increasing access to mobile technologies. / Thesis (BA) — Boston College, 2017. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Economics.