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2011

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Articles 361 - 390 of 1795

Full-Text Articles in Computer Sciences

Linear Obfuscation To Combat Symbolic Execution, Zhi Wang, Jiang Ming, Chunfu Jia, Debin Gao Sep 2011

Linear Obfuscation To Combat Symbolic Execution, Zhi Wang, Jiang Ming, Chunfu Jia, Debin Gao

Research Collection School Of Computing and Information Systems

Trigger-based code (malicious in many cases, but not necessarily) only executes when specific inputs are received. Symbolic execution has been one of the most powerful techniques in discovering such malicious code and analyzing the trigger condition. We propose a novel automatic malware obfuscation technique to make analysis based on symbolic execution difficult. Unlike previously proposed techniques, the obfuscated code from our tool does not use any cryptographic operations and makes use of only linear operations which symbolic execution is believed to be good in analyzing. The obfuscated code incorporates unsolved conjectures and adds a simple loop to the original code, …


Near Optimal Control Of Mobile Robot Formations, Travis Dierks, Bryan Brenner, S. Jagannathan Sep 2011

Near Optimal Control Of Mobile Robot Formations, Travis Dierks, Bryan Brenner, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the infinite horizon optimal tracking control problem is solved online and forward-in-time for leader-follower based formation control of nonholonomic mobile robots. using the backstepping design approach, the dynamical controller inputs for the robots are approximated from nonlinear optimal control techniques in order to track the control velocities designed to keep the formation. the proposed nonlinear optimal control technique, referred to as adaptive dynamic programming, uses neural networks (NN's) to solve the optimal formation control problem in discrete-time in the presence of unknown internal dynamics and a known control coefficient matrix. All NN's are tuned online using novel …


Cross-Layer Throughput Optimization With Power Control In Sensor Networks, Maggie Xiaoyan Cheng, Xuan Gong, Lin Cai, Xiaohua Jia Sep 2011

Cross-Layer Throughput Optimization With Power Control In Sensor Networks, Maggie Xiaoyan Cheng, Xuan Gong, Lin Cai, Xiaohua Jia

Computer Science Faculty Research & Creative Works

In wireless sensor networks, transmission power has a significant impact on network throughput as wireless interference increases with transmission power, and interference negatively impacts the network throughput. in this paper, we try to improve the network throughput through cross-layer optimization. We first present two algorithms to compute the transmission power of each node with the objectives of minimizing the total transmission power and minimizing the total interference, respectively, from which we can obtain a network topology that ensures a connected path from each source to the sink; then, we compute the maximum achievable throughput from the obtained topology by using …


Providing End-To-End Secure Communications In Wireless Sensor Networks, Wenjun Gu, Neelanjana Dutta, Sriram Chellappan, Xiaole Bai Sep 2011

Providing End-To-End Secure Communications In Wireless Sensor Networks, Wenjun Gu, Neelanjana Dutta, Sriram Chellappan, Xiaole Bai

Computer Science Faculty Research & Creative Works

In many Wireless Sensor Networks (WSNs), providing end to end secure communications between sensors and the sink is important for secure network management. While there have been many works devoted to hop by hop secure communications, the issue of end-to-end secure communications is largely ignored. in this paper, we design an end-to-end secure communication protocol in randomly deployed WSNs. Specifically, our protocol is based on a methodology called differentiated key pre-distribution. the core idea is to distribute different number of keys to different sensors to enhance the resilience of certain links. This feature is leveraged during routing, where nodes route …


An Architecture Maturity Model Of Software Product Line, Faheem Ahmed, Luiz Fernando Capretz Sep 2011

An Architecture Maturity Model Of Software Product Line, Faheem Ahmed, Luiz Fernando Capretz

Electrical and Computer Engineering Publications

Software architecture has been a key research area in the software engineering community due to its significant role in creating high-quality software. The trend of developing product lines rather than single products has made the software product line a viable option in the industry. Software product line architecture (SPLA) is regarded as one of the crucial components in the product lines, since all of the resulting products share this common architecture. The increased popularity of software product lines demands a process maturity evaluation methodology. Consequently,this paper presents an architecture process maturity model for software product line engineering to evaluate the …


Security In Intranet And Vpn, Sami Kryeziu Sep 2011

Security In Intranet And Vpn, Sami Kryeziu

Theses and Dissertations

Që nga vitet `70 kur edhe janë vitet e para të internetit që është zbuluar nga ARPANET ku në rrjet numronin katër kompjuter deri në ditët e sotëshme ku numërohen me miliarda përdorues qështja më e ndjeshme ka qenë siguria e këtij rrjeti. Në vitet e fundit ndërthuarja në mes të teknologjis informative dhe bizneseve si dhe mënyra se si të ulen kostot buxhetore duke ju mënjanuar teknologjive të kushtueshme bëri që VPN të jet njëra ndër teknologjit e qëlluara. Virtual Private Network është një teknologji që lindi duke e pasur parasysh nevojën e një komunikimi që ofron siguri të …


Driverguard: A Fine-Grained Protection On I/O Flow, Yueqiang Cheng, Xuhua Ding, Robert H. Deng Sep 2011

Driverguard: A Fine-Grained Protection On I/O Flow, Yueqiang Cheng, Xuhua Ding, Robert H. Deng

Research Collection School Of Computing and Information Systems

Most commodity peripheral devices and their drivers are geared to achieve high performance with security functions being opted out. The absence of security measures invites attacks on the I/O data and consequently threats those applications feeding on them, such as biometric authentication. In this paper, we present the design and implementation of DriverGuard, a hypervisor based protection mechanism which dynamically shields I/O flows such that I/O data are not exposed to the malicious kernel. Our design leverages a composite of cryptographic and virtualization techniques to achieve fine-grained protection. DriverGuard is lightweight as it only needs to protect around 2% of …


Kino: A Generic Document Management System For Biologists Using Sa-Rest And Faceted Search, Ajith Harshana Ranabahu, Priti Parikh, Maryam Panahiazar, Amit P. Sheth Sep 2011

Kino: A Generic Document Management System For Biologists Using Sa-Rest And Faceted Search, Ajith Harshana Ranabahu, Priti Parikh, Maryam Panahiazar, Amit P. Sheth

Kno.e.sis Publications

Document management has become an important consideration for the scientific community over the last decade. Human knowledge is central to many scientific domains, thus it is not possible to completely automate the document management process. Managing scientific documents require a semi-automatic approach to overcome issues of large volume, yet support the human participation in the process. In this paper we present Kino, a set of tools that streamline the document management process in life science domains. Kino is integrated with National Center for Biomedical Ontology (NCBO), providing scientists access to quality domain models. Annotated documents are indexed using a faceted …


On Portability And Scalability Issues In Heterogeneous Computing, Zhu Wang Sep 2011

On Portability And Scalability Issues In Heterogeneous Computing, Zhu Wang

Student Theses and Dissertations

In heterogeneous computing systems, computing nodes might be different whereas each computing node contains different system resources such as processors, graphics processing units, memories, networks, storage units, etc. These computing nodes and their internal resources have to collaborate well to provide required computing capacity. Portability is always an issue in heterogeneous computing systems. Data generated on one machine might not be able to be used by others directly because of the incompatibility issues. Data type, endianness, size and padding situation are different in heterogeneous and even in homogeneous computing systems. Data marshaling procedure is indispensable, especially in open systems. In …


Iterative Learning From Texts And Counterexamples Using Additional Information, Sanjay Jain, Efim Kinber Sep 2011

Iterative Learning From Texts And Counterexamples Using Additional Information, Sanjay Jain, Efim Kinber

School of Computer Science & Engineering Faculty Publications

A variant of iterative learning in the limit (cf. Lange and Zeugmann 1996) is studied when a learner gets negative examples refuting conjectures containing data in excess of the target language and uses additional information of the following four types: (a) memorizing up to n input elements seen so far; (b) up to n feedback memberships queries (testing if an item is a member of the input seen so far); (c) the number of input elements seen so far; (d) the maximal element of the input seen so far. We explore how additional information available to such learners (defined and …


Riverland 2.0: Blending Of Multiple User-Defined Slopes In A Procedurally Modeled Terrain, Jeffrey Jensen Sep 2011

Riverland 2.0: Blending Of Multiple User-Defined Slopes In A Procedurally Modeled Terrain, Jeffrey Jensen

Master's Projects

This writing project attempts to improve on and add features to the current program called RiverLand originally designed and implemented by Dr. Soon Tee Teoh. I discuss the original methods used by RiverLand to create procedurally generated terrain. I then explore the weaknesses of the original RiverLand which include having only linear ridges and undesirable medial axis cells. I then tackle the problem of recurring patterns when texturizing a surface with very few textures. I propose how to solve these problems and explain the methods used to accomplish this. I discuss the user interfaces that were designed to accommodate the …


Information Quality On The World Wide Web: Development Of A Framework, J. Kandari, E. Jones, Fiona Fui-Hoon Nah, R. Bishu Sep 2011

Information Quality On The World Wide Web: Development Of A Framework, J. Kandari, E. Jones, Fiona Fui-Hoon Nah, R. Bishu

Research Collection School Of Computing and Information Systems

Data consumers are provided with easy online access to information on the World Wide Web. However, consumers face information quality problems in their quest for information. This paper focuses on the development of an instrument to measure information quality (IQ) on the World Wide Web from a user's perspective. Based on a comprehensive review of the literature, 20 important IQ frameworks were identified. These models, though varied in their approach and application, share a number of characteristics regarding their classifications of the attributes of quality. The paper identifies common dimensions that exist across the existing IQ frameworks in the literature …


Certificateless Cryptography With Kgc Trust Level 3, Guomin Yang, Chik How Tan Sep 2011

Certificateless Cryptography With Kgc Trust Level 3, Guomin Yang, Chik How Tan

Research Collection School Of Computing and Information Systems

A normal certificateless cryptosystem can only achieve KGC trust level 2 according to the trust hierarchy defined by Girault. Although in the seminal paper introducing certificateless cryptography, Al-Riyami and Paterson introduced a binding technique to lift the KGC trust level of their certificateless schemes to level 3, many subsequent work on certificateless cryptography just focused on the constructions of normal certificateless schemes, and a formal study on the general applicability of the binding technique to these existing schemes is still missing. In this paper, to address the KGC trust level issue, we introduce the notion of Key Dependent Certificateless Cryptography …


Tackling Latency Using Fg, Priya Natarajan Sep 2011

Tackling Latency Using Fg, Priya Natarajan

Dartmouth College Ph.D Dissertations

Applications that operate on datasets which are too big to fit in main memory, known in the literature as external-memory or out-of-core applications, store their data on one or more disks. Several of these applications make multiple passes over the data, where each pass reads data from disk, operates on it, and writes data back to disk. Compared with an in-memory operation, a disk-I/O operation takes orders of magnitude (approx. 100,000 times) longer; that is, disk-I/O is a high-latency operation. Out-of-core algorithms often run on a distributed-memory cluster to take advantage of a cluster's computing power, memory, disk space, and …


Improving Occupancy Grid Fastslam By Integrating Navigation Sensors, Christopher Weyers, Gilbert L. Peterson Sep 2011

Improving Occupancy Grid Fastslam By Integrating Navigation Sensors, Christopher Weyers, Gilbert L. Peterson

Faculty Publications

When an autonomous vehicle operates in an unknown environment, it must remember the locations of environmental objects and use those object to maintain an accurate location of itself. This vehicle is faced with Simultaneous Localization and Mapping (SLAM), a circularly defined robotics problem of map building with no prior knowledge. The SLAM problem is a difficult but critical component of autonomous vehicle exploration with applications to search and rescue missions. This paper presents the first SLAM solution combining stereo cameras, inertial measurements, and vehicle odometry into a Multiple Integrated Navigation Sensor (MINS) path. The FastSLAM algorithm, modified to make use …


An Efficient Adaptive Vortex Particle Method For Real-Time Smoke Simulation, Shengfeng He, Hon-Cheng Wong, Un-Hong Wong Sep 2011

An Efficient Adaptive Vortex Particle Method For Real-Time Smoke Simulation, Shengfeng He, Hon-Cheng Wong, Un-Hong Wong

Research Collection School Of Computing and Information Systems

Smoke simulation is one of the interesting topics in computer animation and it usually involves turbulence generation. Efficient generation of realistic turbulent flows becomes one of the challenges in smoke simulation. Vortex particle method, which is a hybrid method that combines grid-based and particle-based approaches, is often used for generating turbulent details. However, it may cause irrational artifacts due to its initial condition and vorticity forcing approach used. In this paper, a new vorticity forcing approach based on the spatial adaptive vorticity confinement is proposed to address this problem. In this approach, the spatial adaptive vorticity confinement force varies with …


Effective Communication Of Software Development Knowledge Through Community Portals, Christoph Treude, Margaret-Anne Storey Sep 2011

Effective Communication Of Software Development Knowledge Through Community Portals, Christoph Treude, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

Knowledge management plays an important role in many software organizations. Knowledge can be captured and distributed using a variety of media, including traditional help files and manuals, videos, technical articles, wikis, and blogs. In recent years, web-based community portals have emerged as an important mechanism for combining various communication channels. However, there is little advice on how they can be effectively deployed in a software project.In this paper, we present a first study of a community portal used by a closed source software project. Using grounded theory, we develop a model that characterizes documentation artifacts along several dimensions, such as …


Enhancing Brand Equity Through Flow And Telepresence: A Comparison Of 2d And 3d Virtual Worlds, Fiona Fui-Hoon Nah, B. Eschenbrenner, D. Dewester Sep 2011

Enhancing Brand Equity Through Flow And Telepresence: A Comparison Of 2d And 3d Virtual Worlds, Fiona Fui-Hoon Nah, B. Eschenbrenner, D. Dewester

Research Collection School Of Computing and Information Systems

This research uses theories of flow, telepresence, positive emotions, and brand equity to examine the effect of using two-dimensional versus three-dimensional virtual world environments on telepresence, enjoyment, brand equity, and behavioral intention. The findings suggest that the 3D virtual world environment produces both positive and negative effects on brand equity when compared to the 2D environment. The positive effect of the 3D virtual world environment on brand equity occurs through telepresence, a specific aspect of flow, as well as enjoyment. The negative effect on brand equity can be explained using distraction-conflict theory in which attentional conflicts faced by users of …


Mining Top-K Large Structural Patterns In A Massive Network, Feida Zhu, Qiang Qu, David Lo, Xifeng Yan, Jiawei Han, Philip S. Yu Sep 2011

Mining Top-K Large Structural Patterns In A Massive Network, Feida Zhu, Qiang Qu, David Lo, Xifeng Yan, Jiawei Han, Philip S. Yu

Research Collection School Of Computing and Information Systems

With ever-growing popularity of social networks, web and bio-networks, mining large frequent patterns from a single huge network has become increasingly important. Yet the existing pattern mining methods cannot offer the efficiency desirable for large pattern discovery. We propose Spider- Mine, a novel algorithm to efficiently mine top-K largest frequent patterns from a single massive network with any user-specified probability of 1 − ϵ. Deviating from the existing edge-by-edge (i.e., incremental) pattern-growth framework, SpiderMine achieves its efficiency by unleashing the power of small patterns of a bounded diameter, which we call “spiders”. With the spider structure, our approach adopts a …


On Detection Of Erratic Arguments, Jin Han, Qiang Yan, Robert H. Deng, Debin Gao Sep 2011

On Detection Of Erratic Arguments, Jin Han, Qiang Yan, Robert H. Deng, Debin Gao

Research Collection School Of Computing and Information Systems

Due to the erratic nature, the value of a function argument in one normal program execution could become illegal in another normal execution context. Attacks utilizing such erratic arguments are able to evade detections as fine-grained context information is unavailable in many existing detection schemes. In order to obtain such fine-grained context information, a precise model on the internal program states has to be built, which is impractical especially monitoring a closed source program alone. In this paper, we propose an intrusion detection scheme which builds on two diverse programs providing semantically-close functionality. Our model learns underlying semantic correlation of …


Structural Complexity And Programmer Team Strategy: An Experimental Test, Narayan Ramasubbu, Chris F. Kemerer, Jeff Min Teck Hong Sep 2011

Structural Complexity And Programmer Team Strategy: An Experimental Test, Narayan Ramasubbu, Chris F. Kemerer, Jeff Min Teck Hong

Research Collection School Of Computing and Information Systems

This study develops and empirically tests the idea that the impact of structural complexity on perfective maintenance of object-oriented software is significantly determined by the team strategy of programmers (independent or collaborative). We analyzed two key dimensions of software structure, coupling and cohesion, with respect to the maintenance effort and the perceived ease-of-maintenance by pairs of programmers. Hypotheses based on the distributed cognition and task interdependence theoretical frameworks were tested using data collected from a controlled lab experiment employing professional programmers. The results show a significant interaction effect between coupling, cohesion, and programmer team strategy on both maintenance effort and …


Towards Ground Truthing Observations In Gray-Box Anomaly Detection, Jiang Ming, Haibin Zhang, Debin Gao Sep 2011

Towards Ground Truthing Observations In Gray-Box Anomaly Detection, Jiang Ming, Haibin Zhang, Debin Gao

Research Collection School Of Computing and Information Systems

Anomaly detection has been attracting interests from researchers due to its advantage of being able to detect zero-day exploits. A gray-box anomaly detector first observes benign executions of a computer program and then extracts reliable rules that govern the normal execution of the program. However, such observations from benign executions are not necessarily true evidences supporting the rules learned. For example, the observation that a file descriptor being equal to a socket descriptor should not be considered supporting a rule governing the two values to be the same. Ground truthing such observations is a difficult problem since it is not …


Structural Analysis Of The Hot Spots In The Binding Between H1n1 Ha And The 2di Antibody: Do Mutations Of H1n1 From 1918 To 2009 Affect Much On This Binding?, Qian Liu, Steven C. H. Hoi, Chinh T. T. Su, Zhenhua Li, Chee-Keong Kwoh, Limsoon Wong, Jinyan Li Sep 2011

Structural Analysis Of The Hot Spots In The Binding Between H1n1 Ha And The 2di Antibody: Do Mutations Of H1n1 From 1918 To 2009 Affect Much On This Binding?, Qian Liu, Steven C. H. Hoi, Chinh T. T. Su, Zhenhua Li, Chee-Keong Kwoh, Limsoon Wong, Jinyan Li

Research Collection School Of Computing and Information Systems

Worldwide and substantial mortality caused by the 2009 H1N1 influenza A has stimulated a new surge of research on H1N1 viruses. An epitope conservation has been learned in the HA1 protein that allows antibodies to cross-neutralize both 1918 and 2009 H1N1. However, few works have thoroughly studied the binding hot spots in those two antigen–antibody interfaces which are responsible for the antibody cross-neutralization. We apply predictive methods to identify binding hot spots at the epitope sites of the HA1 proteins and at the paratope sites of the 2D1 antibody. We find that the six mutations at the HA1's epitope from …


Spectral Geometry Image: Image Based 3d Models For Digital Broadcasting Applications, Boon Seng Chew, Lap Pui Chau, Ying He, Dayong Wang, Steven C. H. Hoi Sep 2011

Spectral Geometry Image: Image Based 3d Models For Digital Broadcasting Applications, Boon Seng Chew, Lap Pui Chau, Ying He, Dayong Wang, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

The use of 3D models for progressive transmission and broadcasting applications is an interesting challenge due to the nature and complexity of such content. In this paper, a new image format for the representation of 3D progressive model is proposed. The powerful spectral analysis is combined with the state of art Geometry Image(GI) to encode static 3D models into spectral geometry images(SGI) for robust 3D shape representation. Based on the 3D model's surface characteristics, SGI separated the geometrical image into low and high frequency layers to achieve effective Level of Details(LOD) modeling. For SGI, the connectivity data of the model …


When Recommendation Meets Mobile: Contextual And Personalised Recommendation On The Go, Jinfeng Zhuang, Tao Mei, Steven C. H. Hoi, Ying-Qing Xu, Shipeng Li Sep 2011

When Recommendation Meets Mobile: Contextual And Personalised Recommendation On The Go, Jinfeng Zhuang, Tao Mei, Steven C. H. Hoi, Ying-Qing Xu, Shipeng Li

Research Collection School Of Computing and Information Systems

Mobile devices are becoming ubiquitous. People use their phones as a personal concierge discovering and making decisions anywhere and anytime. Understanding user intent on the go therefore becomes important for task completion on the phone. While existing efforts have predominantly focused on understanding the explicit user intent expressed by a textual or voice query, this paper presents an approach to context-aware and personalized entity recommendation which understands the implicit intent without any explicit user input on the phone. The approach, highly motivated from a large-scale mobile click-through analysis, is able to rank both the entity types and the entities within …


Tamper Detection In The Epc Network Using Digital Watermarking, Shui-Hua Han, Chao-Hsien Chu, Zongwei Luo Sep 2011

Tamper Detection In The Epc Network Using Digital Watermarking, Shui-Hua Han, Chao-Hsien Chu, Zongwei Luo

Research Collection School Of Computing and Information Systems

One of the most relevant problems in radio frequency identification (RFID) technology is the lack of security measures in its wireless communication channel between the reader and tag. This article analyzes potential data tampering threats in the electronic product code (EPC) network and proposes solutions using fragile watermarking technologies.


Improved Ordinary Measure And Image Entropy Theory Based Intelligent Copy Detection Method, Dengpan Ye, Longfei Ma, Lina Wang, Robert H. Deng Sep 2011

Improved Ordinary Measure And Image Entropy Theory Based Intelligent Copy Detection Method, Dengpan Ye, Longfei Ma, Lina Wang, Robert H. Deng

Research Collection School Of Computing and Information Systems

Nowadays, more and more multimedia websites appear in social network. It brings some security problems, such as privacy, piracy, disclosure of sensitive contents and so on. Aiming at copyright protection, the copy detection technology of multimedia contents becomes a hot topic. In our previous work, a new computer-based copyright control system used to detect the media has been proposed. Based on this system, this paper proposes an improved media feature matching measure and an entropy based copy detection method. The Levenshtein Distance was used to enhance the matching degree when using for feature matching measure in copy detection. For entropy …


Privacy Beyond Single Sensitive Attribute, Yuan Fang, Mafruz Zaman Ashrafi, See Kiong Ng Sep 2011

Privacy Beyond Single Sensitive Attribute, Yuan Fang, Mafruz Zaman Ashrafi, See Kiong Ng

Research Collection School Of Computing and Information Systems

Publishing individual specific microdata has serious privacy implications. The k-anonymity model has been proposed to prevent identity disclosure from microdata, and the work on ℓ-diversity and t-closeness attempt to address attribute disclosure. However, most current work only deal with publishing microdata with a single sensitive attribute (SA), whereas real life scenarios often involve microdata with multiple SAs that may be multi-valued. This paper explores the issue of attribute disclosure in such scenarios. We propose a method called CODIP (Complete Disjoint Projections) that outlines a general solution to deal with the shortcomings in a naïve approach. We also introduce two measures, …


Anomaly Detection In Network Streams Through A Distributional Lens, Chrisil Arackaparambil Sep 2011

Anomaly Detection In Network Streams Through A Distributional Lens, Chrisil Arackaparambil

Dartmouth College Ph.D Dissertations

Anomaly detection in computer networks yields valuable information on events relating to the components of a network, their states, the users in a network and their activities. This thesis provides a unified distribution-based methodology for online detection of anomalies in network traffic streams. The methodology is distribution-based in that it regards the traffic stream as a time series of distributions (histograms), and monitors metrics of distributions in the time series. The effectiveness of the methodology is demonstrated in three application scenarios. First, in 802.11 wireless traffic, we show the ability to detect certain classes of attacks using the methodology. Second, …


Extensions Of Snomed Taxonomy Abstraction Networks Supporting Auditing And Complexity Analysis, Duo Wei Aug 2011

Extensions Of Snomed Taxonomy Abstraction Networks Supporting Auditing And Complexity Analysis, Duo Wei

Dissertations

The Systematized Nomenclature of Medicine – Clinical Terms (SNOMED CT) has been widely used as a standard terminology in various biomedical domains. The enhancement of the quality of SNOMED contributes to the improvement of the medical systems that it supports.

In previous work, the Structural Analysis of Biomedical Ontologies Center (SABOC) team has defined the partial-area taxonomy, a hierarchical abstraction network consisting of units called partial-areas. Each partial-area comprises a set of SNOMED concepts exhibiting a particular relationship structure and being distinguished by a unique root concept. In this dissertation, some extensions and applications of the taxonomy framework are considered. …