M.S. - Information and Computer Sciences
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ItemThe Cipher Mail Transport Protocol (CMTP)([Honolulu] : [University of Hawaii at Manoa], [August 2016], 2016-08)The Cipher Mail Transport Protocol (CMTP) is a new mail transport system designed to make encryption the default option for email. This thesis lays out what a modern email system is, how it works, the shortcomings of the current system and will propose CMTP as a solution. CMTP provides a solution to these problems in an effort to secure email transmission and storage. In- spired by the Pretty Good Privacy (PGP) email security system, CMTP implements public key cryptography, hidden from users, while maintaining the broad usability of email. This is in contrast to secure protocols that pre-date CMTP and generally provide good security, but reduce usability. After an initial, unauthenticated key exchange, CMTP encrypts and authenticates all messages. In this way, CMTP provides security without compromising usability.
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ItemAutomated cinematography and editing for 3D computer graphics scenes([Honolulu] : [University of Hawaii at Manoa], [December 2010], 2010-12)We present an approach to generate cinematic sequences from event-based descriptions of 3D computer graphics scenes of conversations between groups of actors. We break the problem into two parts: cinematography and editing. Our cinematography approach creates camera setups using a combination of geometric constraints and aesthetic parameters, while ensuring that the resulting cinematic sequence obeys the heuristics of traditional cinematography. More specifically, our main contributions are a method for defining hierarchical lines of action and the identification and use of relevant first principles of cinematography for using these lines of actions. Our approach is more flexible and powerful than those proposed in previous work, mainly because it naturally generalizes to any number of actors in a scene. On the editing side, we present a set of heuristics for editing shots into a coherent movie clip which obeys the conventions of continuity editing. Our approach mimics the decision processes of an editor assembling a clip out of filmed footage involving multiple camera setups. Given a set of stylistic rules, our software applies a number of heuristics to produce a final result satisfying those rules, as well as the fundamental rules of continuity editing. The main contribution of this work is in the formulation of editing heuristics which take into account stylistic rules, enabling different edits of the same scene into cinematic clips of various styles. We demonstrate the use of these heuristics on three scenes taken from actual film clips.
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ItemThe Lusus Protocol( 2005-08)Wireless sensor networks are groups of nodes which sample data from one or more attached sensors and cooperate via wireless links to transmit this data to a destination. This document introduces Lusus, a new protocol designed to operate wireless sensor networks for ecological monitoring. Unlike other protocols with a more general design focus, Lusus assumes that the vast majority of information travels towards a central point. This allows Lusus to use specific routes in an efficient manner since the only route a node need know is the next hop towards the center of the network. Lusus uses a limited form of route discovery transmitted periodically from the center of the network and relayed by each node in the network. This periodic route discovery flood is done on the order of hours to save bandwidth. The routing overhead in Lusus is significantly less than in other protocols. Lusus assumes that data items are small (several bytes) in size. Furthermore Lusus is designed to optimize transferring small units of data. Individual pieces of data in a Lusus network are packaged within self-contained units. Because of this, nodes are allowed to combine the data from multiple separate packets into a single outgoing packet. This allows Lusus networks to save on overhead and thus increase their efficiency. This combining of data results in an overhead of 27% per piece of data whereas without combining the overhead is 85%. To help ensure data reception, Lusus uses hop-by-hop acknowledgments. This type of acknowledgment is necessary to support the data combining feature of Lusus. This document describes the operation of Lusus and offers an analysis of its performance for large and for dense networks.
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ItemFactors influencing use of a web-based community space for K-12 professional development(University of Hawaii at Manoa, 2003-12)This study examines participation in an online community space developed to support K-12 professional development efforts conducted as part of a National Science Foundation Rural Systemic lnitiative-Hawaiʻi Networked Learning Communities (HNLC). HNLC was designed to contribute to science, mathematics, engineering, and technology system reform efforts of the Hawaiʻi Department of Education. HNLC's website, hnle.org, was designed to support the HNLC initiative and serve HNLC participants as an online community space. Results indicate that participants have not adopted hnle.org as a tool for their ownuse, and are instead using hnle.org almost exclusively during highly structured workshops where hnle.org use is required. Active participation in the online community is rare. Participant interviews and focus groups revealed that there exists a disconnect between the stated needs of educators and the offerings of hnle.org. Participants were primarily concerned with uses of technology by their students, while hnle.org is targeted to educators' own professional development efforts.
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ItemMultipath on-demand routing in sensor network topologies(University of Hawaii at Manoa, 2003-05)The Multi-path On-demand Routing (MOR) Protocol is an on-demand, load balancing routing protocol designed for the Pods project at the University of Hawaiʻi at Manoa. Pods is a Remote Ecological Micro-Sensor Network where robustness and energy efficiency are high priorities. Pods sensors are wireless and often cannot communicate with a base station directly. MOR addresses these Pods needs through an on-demand routing mechanism using multiple paths where possible. MOR differs from other protocols in the use of a hop-by-hop reliability layer to optimize data delivery in low mobility environments. The reliability layer reroutes packets that fail to transmit (to the next hop) to a different path. Rerouting is possible since MOR utilize gradients for route direction, resulting in non-disjoint multipaths. MOR attempts to lower energy usage by minimizing the number of network floods necessary to establish routes. MOR was compared using simulation with DSR and AODV in reasonable dense and sparse sensor network topologies. MOR showed substantial improvements over DSR and AODV in terms of energy use and data delivery rate.
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ItemImproving software quality through extreme coverage with Jblanket(University of Hawaii at Manoa, 2003-05)Unit testing is an important part of software testing that aids in the discovery of bugs sooner in the software development process. Extreme Programming (XP), and its Test First Design technique, relies so heavily upon unit tests that the first code implemented is made up entirely of test cases. Furthermore, XP considers a feature to be completely coded only when all of its test cases pass. However, passing all test cases does not necessarily mean the test cases are good. Extreme Coverage (XC) is a new approach that helps to assess and improve the quality of software by enhancing unit testing. It extends the XP requirement that all test cases must pass with the requirement that all defect-prone testable methods must be invoked by the tests. Furthermore, a set of flexible rules are applied to XC to make it as attractive and light-weight as unit testing is in XP' One example rule is to exclude all methods containing one line of code from analysis. I designed and implemented a new tool, called JBlanket, that automates the XC measurement process similar to the way that JUnit automates unit testing. JBlanket produces HTML reports similar to JUnit reports which inform the user about which methods need to be tested next. In this research, I explore the feasibility of JBlanket, the amount of effort needed to reach and maintain XC, and the impact that knowledge of XC has on system implementation through deployment and evaluation in an academic environment. Results show that most students find JBlanket to be a useful tool in developing their test cases, and that knowledge of XC did influence the manner in which students implemented their systems. However, more studies are needed to conclude precisely how much effort is needed to reach and maintain XC. This research lays the foundation for future research directions. One direction involves increasing its flexibility and value by expanding and refining the rules of XC. Another direction involves tracking XC behavior to find out when it is and is not applicable.