Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 156-159). Also available in electronic version. Access restricted to campus users.

Thesis (M.S.)--University of Florida, 2002. / Title from title page of source document. Includes vita. Includes bibliographical references.

Thesis (MTech. degree in Information Networks)--Tshwane University of Technology, 2009. / With this research, we focus on utilizing a distributed file system to combat congestion problems in wireless networks. The Coda file system is our choice of a distributed file system, as it offers several services, such as data pre-fetching, hoarding of files, disconnected operation and data consistency.

This report describes PlaceMe, a client side, mobile application built on the Android platform that provides personal location-based services such as location reminders, bookmarking, mapping and search nearby. The reminder system allows creating location based reminders, and alerts the user what he needs to do, when he is in the right place to do them. Bookmarking allows the user to virtually “save” places of interest while he is on the move and obtain driving directions. Mapping enables the user to visualize his relative geographic location in real time, and map the location reminders and bookmarks. Finally, search nearby exploits Google’s powerful local search engine to allow finding and bookmarking nearby places such as gas stations, restaurants, etc, and retrieving map-based directions. We first discuss the requirements and use-cases for PlaceMe, followed an introduction to the Android software stack. Next, we describe our design architecture, implementation model, test strategy and key performance enhancements. Then, we evaluate and compare the performance of the Android platform across a set of standard micro-benchmarks. Finally, we conclude with a discussion of future development ideas and present our thoughts on prospects of app-based mobile computing. / text

published_or_final_version / abstract / toc / Electrical and Electronic Engineering / Master / Master of Philosophy

The past few years have witnessed a significant evolution in mobile computing and communications, in which new trends and applications have the traditional role of computer networks into that of distributed service providers. In this thesis we explore an alternative way to form wireless ad-hoc networks whose topologies can be customized as required by the users’ software applications. In particular, we investigate the applicability of mobile codes to networks created by devices equipped with Bluetooth technology. Computer simulations results suggest that our proposed approach can achieve this task effectively, while matching the level of efficiency seen in other salient proposals in this area. This thesis also addresses the issue of service discovery in mobile ad-hoc networks. We propose the use of a directory whose network location varies in an attempt to reduce traffic overhead driven by users’ hosts looking for service information. We refer to this scheme as the Service Directory Placement Algorithm, or SDPA. We formulate the directory relocation problem as a Markov Decision Process that is solved by using Q-learning. Performance evaluations through computer simulations reveal bandwidth overhead reductions that range between 40% and 48% when compared with a basic broadcast flooding approach for networks comprising hosts moving at pedestrian speeds. We then extend our proposed approach and introduce a multi-directory service discovery system called the Service Directory Placement Protocol, or SDPP. Our findings reveal bandwidth overhead reductions typically ranging from 15% to 75% in networks comprising slow-moving hosts with restricted memory availability. In the fourth and final part of this work, we present the design foundations and architecture of a middleware system that called WISEMAN – WIreless Sensors Employing Mobile Agents. We employ WISEMAN for dispatching and processing mobile programs in Wireless Sensor Networks (WSNs). Our proposed system enables the dynamic creation of semantic relationships between network nodes that cooperate to provide an aggregate service. We present discussions on the advantages of our proposed approach, and in particular, how WISEMAN facilitates the realization of service-oriented tasks in WSNs.

<p>Sleek and powerful touchscreen devices with continuous access to high-bandwidth wireless data networks have transformed mobile into a first-class development platform. Many applications (i.e., "apps") written for these platforms rely on remote services such as Dropbox, Facebook, and Twitter, and require users to provide one or more passwords upon installation. Unfortunately, today's mobile platforms provide no protection for users' passwords, even as mobile devices have become attractive targets for password-stealing malware and other phishing attacks.</p><p>This dissertation explores the feasibility of providing strong protections for passwords input on mobile devices without requiring large changes to existing apps.</p><p>We propose two approaches to secure password entry on mobile devices: ScreenPass and VeriUI. ScreenPass is integrated with a device's operating system and continuously monitors the device's screen to prevent malicious apps from spoofing the system's trusted software keyboard. The trusted keyboard ensures that ScreenPass always knows when a password is input, which allows it to prevent apps from sending password data to the untrusted servers. VeriUI relies on trusted hardware to isolate password handling from a device's operating system and apps. This approach allows VeriUI to prove to remote services that a relatively small and well-known code base directly handled a user's password data.</p> / Dissertation

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Mobile devices are increasingly being relied on for computation intensive and/or communication intensive applications that go beyond simple connectivity and demand more complex processing. This has been made possible by two trends. First, mobile devices, such as smartphones and tablets, are increasingly capable devices with processing and storage capabilities that make significant step improvements with every generation. Second, many improved connectivity options (e.g., 3G, WiFi, Bluetooth) are also available to mobile devices. In the rich computing and communication environment, it is promising but also challenging for mobile devices to take advantage of various available resources to improve the performance of mobile applications. First, with varying connectivity, remote computing resources are not always accessible to mobile devices in a predictable way. Second, given the uncertainty of connectivity and computing resources, their contention will become severe. This thesis seeks to address the connectivity challenges for mobile computing and communication. We propose a set of techniques and systems that help mobile applications to better handle the varying network connectivity in the utilization of various computation and communication resources. This thesis makes the following contributions: We design and implement Serendipity to allow a mobile device to use other encountered, albeit intermittently, mobile devices to speedup the execution of parallel applications through carefully allocating computation tasks among intermittently connected mobile devices. We design and implement IC-Cloud to enable a group of mobile devices to efficiently use the cloud computing resources for computation offloading even when the connectivity is varying or intermittent. We design and implement COSMOS to provide scalable computation offloading service to mobile devices at low cost by efficiently managing and allocating cloud computing resources. We design and implement CoAST to allow collaborative application-aware scheduling of mobile traffic to reduce the contention for bandwidth among communication-intensive applications without affecting their user experience.