Computer Sciences Commons^™

Location Update Versus Paging Trade-Off In Cellular Networks: An Approach Based On Vector Quantization, Abhishek Roy, Archan Misra, Sajal K. Das

Research Collection School Of Computing and Information Systems

In this paper we propose two information-theoretic techniques for efficiently trading off the location update and paging costs associated with mobility management in wireless cellular networks. Previous approaches attempt to always accurately convey a mobile's movement sequence and hence, cannot reduce the signaling cost below the entropy bound. Our proposed techniques, however, exploit rate-distortion theory to arbitrarily reduce the update cost, at the expense of an increase in the corresponding paging overhead. To this end, we describe two location tracking algorithms, based on spatial quantization and temporal quantization, which first quantize the movement sequence into a smaller set of codewords, …

Malicious Mobile Code Related Experiments With An Extensible Network Simulator, Attila Ondi

Theses and Dissertations

The automated spread of worms such as Code-Red, SQL/Slammer, and Nimda have caused costly problems to computers connected to the Internet. Even users whose machines were not vulnerable to these threats suffered a loss of productivity and experienced great frustration as connectivity and network traffic were negatively impacted during outbreaks. Although the number of new worm attacks reported in the media seems to be declining, it is vital that researchers study the effects of malicious code on the global network to understand how to defend against future threats. The choice of system for studying the spread of worms and viruses …

Matching And Fairness In Threat-Based Mobile Sensor Coverage, Chris Y. T. Ma, Jren-Chit Chin, David K.Y. Yau, Nageswara S. Rao, Mallikarjun Shankar

Department of Computer Science Technical Reports

No abstract provided.

A Direct Algorithm For The K-Nearest-Neighbor Classifier Via Local Warping Of The Distance Metric, Tohkoon Neo

Theses and Dissertations

The k-nearest neighbor (k-NN) pattern classifier is a simple yet effective learner. However, it has a few drawbacks, one of which is the large model size. There are a number of algorithms that are able to condense the model size of the k-NN classifier at the expense of accuracy. Boosting is therefore desirable for increasing the accuracy of these condensed models. Unfortunately, there does not exist a boosting algorithm that works well with k-NN directly. We present a direct boosting algorithm for the k-NN classifier that creates an ensemble of models with locally modified distance weighting. An empirical study conducted …

[Accepted Article Manuscript Version (Postprint)] The Social Implications Of Enjoyment Of Different Types Of Music, Movies, And Television Programming, Alice Hall

Communication and Media Faculty Works

This study investigated how information about an individual’s enjoyment of various genres of music, film, and TV programming could influence an observer’s expectations of that individual. An online survey of young adults found that the influence of information about another person’s genre preferences varied across genres. Enjoyment of some genres, including jazz music, film comedies, and television comedies, tended to raise expectations of the individual, whereas enjoyment of others, including heavy metal music, anime films, and television soap operas, tended to lower them. The implications of the findings are discussed in relation to uses and gratifications perspectives as well as …

Scalable And Adaptive Metadata Management In Ultra Large-Scale File Systems, Yu Hua, Yifeng Zhu, Hong Jiang

School of Computing: Technical Reports

This paper presents a scalable and adaptive decentralized metadata lookup scheme for ultra large-scale file systems (≥ Petabytes or even Exabytes). Our scheme logically organizes metadata servers (MDS) into a multi-layered query hierarchy and exploits grouped Bloom filters to efficiently route metadata requests to desired MDSs through the hierarchy. This metadata lookup scheme can be executed at the network or memory speed, without being bounded by the performance of slow disks. An effective workload balance algorithm is also developed in this paper for server reconfigurations. This scheme is evaluated through extensive trace-driven simulations and prototype implementation in Linux. Experimental results …

Supporting Annotated Relations, M. Y. Eltabakh, M. Ouzzani, Walid G. Aref, Ahmed K. Elmagarmid, Y. Laura-Silva

Department of Computer Science Technical Reports

No abstract provided.

Effects Of Dependency Injection On Maintainability, Ekaterina Razina, David S. Janzen

Computer Science and Software Engineering

Software maintenance consumes around 70% of the software life cycle. Improving software maintainability could save software developers significant time and money. This paper examines whether the pattern of dependency injection significantly reduces dependencies of modules in a piece of software, therefore making the software more maintainable. This hypothesis is tested with 20 sets of open source projects from sourceforge.net, where each set contains one project that uses the pattern of dependency injection and one similar project that does not use the pattern. The extent of the dependency injection use in each project is measured by a new Number of DIs …

An Architectural Approach To Improving The Availability Of Parity-Based Raid Systems, Lei Tian, Hong Jiang, Dan Feng, Qin Xin, Sai Huang

School of Computing: Technical Reports

In this paper, we propose an architectural approach, Supplementary Partial Parity (SPP), to addressing the availability issue of parity encoded RAID systems. SPP exploits free storage space and idle time to generate and update a set of partial parity units that cover a subset of disks (or data stripe units) during failure-free and idle/lightly-loaded periods, thus supplementing the existing full parity units for improved availability. By applying the exclusive OR operations appropriately among partial parity, full parity and data units, SPP can reconstruct the data on the failed disks with a fraction of the original overhead that is proportional to …

Supporting Views In Data Stream Management System, Thanaa M. Ghanem, Walid G. Aref, Ahmed K. Elmagarmid, Per-Ake Larson

Department of Computer Science Technical Reports

No abstract provided.

Amp: An Affinity-Based Metadata Prefetching Scheme In Large-Scale Distributed Storage Systems, Lin Li, Xuemin Li, Hong Jiang, Yifeng Zhu

School of Computing: Technical Reports

Prefetching is an effective technique for improving file access performance, which can reduce access latency for I/O systems. In distributed storage system, prefetching for metadata files is critical for the overall system performance. In this paper, an Affinity-based Metadata Prefetching (APM) scheme is proposed for metadata servers in large-scale distributed storage systems to provide aggressive metadata prefetching. Through mining useful information about metadata assesses from past history, AMP can discover metadata file affinities accurately and intelligently for prefetching. Compared with LRU and some of the latest file prefetching algorithms such as NEXUS and C-miner, trace-driven simulations show that AMP can …

Supporting Flight Control For Uav-Assisted Wilderness Search And Rescue Through Human Centered Interface Design, Joseph L. Cooper

Theses and Dissertations

Inexpensive, rapidly deployable, camera-equipped Unmanned Aerial Vehicle (UAV) systems can potentially assist with a huge number of tasks. However, in many cases such as wilderness search and rescue (WiSAR), the potential users of the system may not be trained as pilots. Simple interface concepts can be used to build an interaction layer that allows an individual with minimal operator training to use the system to facilitate a search or inspection task. We describe an analysis of WiSAR as currently accomplished and show how a UAV system might fit into the existing structure. We then discuss preliminary system design efforts for …

Leveraging Semantic Web Techniques To Gain Situational Awareness, Amit P. Sheth

Kno.e.sis Publications

No abstract provided.

Camp: A Common Api For Measuring Performance, Mark Gabel, Michael Haungs

Computer Science and Software Engineering

Accurate performance testing of heterogeneous distributed systems, such as those created using GRID technology, requires a consistent method for retrieving system performance data from multiple platforms. This paper presents CAMP: a low-level platform independent performance data API designed for use with distributed testing frameworks.

CAMP is not necessarily tied to the distributed testing task: it provides a simple, low-level interface into operating system performance data that can be used to build complex performance measurement applications. This paper discusses CAMP's functionality and implementation in detail. It also contains a detailed analysis of the API's correctness, performance, and overhead.

Interactive Thin Shells – A Model Interface For The Analysis Of Physically-Based Animation, James Skorupski, Zoë J. Wood, Alex Pang

Computer Science and Software Engineering

Realism has always been a goal in computer graphics. However, the algorithms involved in mimicking the physical world are often complex, abstract, and sensitive to changes in experimental parameters. We present an interface to a physically-based algorithm, a thin shell animation, which focuses on visualization, experimentation, and control. Through the use of dynamic surface coloring, abstract visual cues, robust user interaction, and full control over the algorithm parameters, our system facilitates experimentation and the process of discovery. The system is targeted at enhancing the user’s learning experience by clarifying interactions between various components of many physically-based animations.

Organization And Management Of The Sead Help Desk, Ann Evans Durbin

Regis University Student Publications (comprehensive collection)

ARNe (Regis University Academic Research Network Enterprise), is the graduate student run and managed intranet which is organized as an IT company. The operating structure is based upon a Service Oriented Architecture where each student is involved in an operating portion of the network. New students participating in the SEAD practicum are required to work the ARNe help desk as a requirement of their project. They are expected to login to Track-It! on a daily basis and check for new tickets in the queue. The tickets are submitted by students as well as faculty. Without having a defined "walk through" …

The Librarian As Hacker, Getting More From Google, R Philip Reynolds

Librarian and Staff Publications

This paper will cover four areas. First it will discuss the research habits of search engine users and some of the problems with these habits. Then it will discuss librarians' use of search engines. Here we encounter the real question: Do we do much better? Can we use a search engines to their full potential? When needed, can we hack an engine to make it perform beyond its intended function? Can we use a clever workaround to solve a problem? Or are we on a level playing field with our patrons once we get outside traditional database searching? Google currently …

Conjunctive Queries For A Tractable Fragment Of Owl 1.1, Markus Krotzsch, Sebastian Rudolph, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Despite the success of the Web Ontology Language OWL, the development of expressive means for querying OWL knowledge bases is still an open issue. In this paper, we investigate how a very natural and desirable form of queries-namely conjunctive ones-can be used in conjunction with OWL such that one of the major design criteria of the latter-namely decidability-can be retained. More precisely, we show that querying the tractable fragment EL++ of OWL 1.1 is decidable. We also provide a complexity analysis and show that querying unrestricted EL++ is undecidable.

Can Semantic Web Techniques Empower Comprehension And Projection In Cyber Situational Awareness?, Amit P. Sheth

Kno.e.sis Publications

No abstract provided.

Semantic Convergence Of Wikipedia Articles, Christopher J. Thomas, Amit P. Sheth

Kno.e.sis Publications

Social networking, distributed problem solving and human computation have gained high visibility. Wikipedia is a well established service that incorporates aspects of these three fields of research. For this reason it is a good object of study for determining quality of solutions in a social setting that is open, completely distributed, bottom up and not peer reviewed by certified experts. In particular, this paper aims at identifying semantic convergence of Wikipedia articles; the notion that the content of an article stays stable regardless of continuing edits. This could lead to an automatic recommendation of good article tags but also add …

Uncertainty As The Source Of Knowledge Transfer Opportunity, Alex Dekhtyar, Jane Huffman Hayes, Judy Goldsmith

Computer Science and Software Engineering

Uncertainty creeps into the software development process in many ways, shapes and forms. In the early stages of software development, key sources of uncertainty are the human stakeholders who help formulate the requirements of the software product. An added layer of uncertainty is inherent as requirements analysts have to deal with subjective, and often conflicting, estimates that humans make, estimates that may significantly affect both the software development process and the eventual software product. Our position is two-fold. We stipulate that in situations where analysts (and later developers) have to deal with human evaluations of uncertainty, special methods and procedures …

Journal Of Combinatorial Optimization, Special Issue On Communication Networks And Internet Applications, Maggie Xiaoyan Cheng

Computer Science Faculty Research & Creative Works

No abstract provided.

Distinct Value Estimation By Sampling On Unstructured Peer To Peer Networks, Zubin Matthew Joseph

Computer Science and Engineering Theses - Archive

Peer-to-Peer networks have become very popular on the Internet, with millions of peers all over the world sharing large volumes of data. The sheer scale of these networks has made it difficult to gather statistics that could be used for building new features. This thesis presents a technique of obtaining estimations of the number of distinct values matching a query on the network. The method is then analyzed by considering simulation results that demonstrate its effectiveness and flexibility in supporting a variety of queries and applications.

Supporting Complex Thematic, Spatial And Temporal Queries Over Semantic Web Data, Matthew Perry, Amit P. Sheth, Farshad Hakimpour, Prateek Jain

Kno.e.sis Publications

Spatial and temporal data are critical components in many applications. This is especially true in analytical domains such as national security and criminal investigation. Often, the analytical process requires uncovering and analyzing complex thematic relationships between disparate people, places and events. Fundamentally new query operators based on the graph structure of Semantic Web data models, such as semantic associations, are proving useful for this purpose. However, these analysis mechanisms are primarily intended for thematic relationships. In this paper, we describe a framework built around the RDF metadata model for analysis of thematic, spatial and temporal relationships between named entities. We …

Mining Modal Scenarios-Based Specifications From Execution Trace Of Reactive Systems, David Lo, Shahar Maoz, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Specification mining is a dynamic analysis process aimed at automatically inferring suggested specifications of a program from its execution traces. We describe a novel method, framework, and tool, for mining inter-object scenario-based specifications in the form of a UML2-compliant variant of Damm and Harels Live Sequence Charts (LSC). LSC extends the classical partial order semantics of sequence diagrams with temporal liveness and symbolic class level lifelines, in order to generate compact and expressive specifications. The output of our algorithm is a sound and complete set of statistically significant LSCs (i.e., satisfying given thresholds of support and confidence), mined from an …

Model Checking In The Absence Of Code, Model And Properties, David Lo, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Model checking is a major approach in ensuring software correctness. It verifies a model converted from code against some formal properties. However, difficulties and programmers ’ reluctance to formalize formal properties have been some hurdles to its widespread industrial adoption. Also, with the advent of commercial off-the-shelf (COTS) components provided by third party vendors, model checking is further challenged as often only a binary version of the code is provided by vendors. Interestingly, latest instrumentation tools like PIN and Valgrind have enable execution traces to be collected dynamically from a running program. In this preliminary study, we investigate what can …

Self-Organization Of Scroll Waves In Excitable Media : Parallel Simulations On A 64-Opteron Linux Cluster, Igor Kaplun

Theses, Dissertations and Culminating Projects

Spiral waves have been observed and studied in a variety of biological, physical and chemical systems, known as excitable media. The most famous examples of excitable media include cardiac tissue, the Belousov-Zhabotinsky chemical reaction, and aggregation of starving slime mold amoeba.

It had been shown previously that spiral waves could self-organize into multi- armed spirals. A 3D analog of a 2D spiral wave is called a scroll wave. It rotates around a 1D imaginary tube known as a filament. A later study based on the so-called Puschino model has reported formation of multi-armed scroll waves in 3D. But a question …

Predictive Congestion Control Protocol For Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Available congestion control schemes, for example transport control protocol (TCP), when applied to wireless networks, result in a large number of packet drops, unfair scenarios and low throughputs with a significant amount of wasted energy due to retransmissions. To fully utilize the hop by hop feedback information, this paper presents a novel, decentralized, predictive congestion control (DPCC) for wireless sensor networks (WSN). The DPCC consists of an adaptive flow and adaptive back-off interval selection schemes that work in concert with energy efficient, distributed power control (DPC). The DPCC detects the onset of congestion using queue utilization and the embedded channel …

Effects Of Electromagnetic Interference On Control Area Network Performance, Fei Ren, Y. Rosa Zheng, Maciej Jan Zawodniok, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the effects of electromagnetic interference (EMI) on control area network (CAN) communications are investigated by hardware experiments. Distinct CAN bit rates, communication cables, and networks are used to test effects of EMI on CAN bus. Waveforms of CAN data frames in EMI environment are observed and analyzed for figuring out details of effects. Experiments show that the EMI pulses frequently encountered in automobile and off-road machinery can cause the reduction of bit rates and errors in high-speed CAN communications. Replacing traditional unshielded parallel communication cables with shielded communication cables is proved to be an effective method of …

Incremental Procedures For Partitioning Highly Intermixed Multi-Class Datasets Into Hyper-Spherical And Hyper-Ellipsoidal Clusters, Qinglu Kong, Qiuming Zhu

Computer Science Faculty Publications

Two procedures for partitioning large collections of highly intermixed datasets of different classes into a number of hyper-spherical or hyper-ellipsoidal clusters are presented. The incremental procedures are to generate a minimum numbers of hyper-spherical or hyper-ellipsoidal clusters with each cluster containing a maximum number of data points of the same class. The procedures extend the move-to-front algorithms originally designed for construction of minimum sized enclosing balls or ellipsoids for dataset of a single class. The resulting clusters of the dataset can be used for data modeling, outlier detection, discrimination analysis, and knowledge discovery.