Digital Commons Network^™

A New Backoff Algorithm For The Ieee 802.11 Distributed Coordination Function, Jing Deng, Pramod K. Varshney, Zygmunt J. Haas

Electrical Engineering and Computer Science - All Scholarship

In the IEEE 802.11 Wireless Local Area Networks (WLANs), network nodes experiencing collisions on the shared channel need to backoff for a random period of time, which is uniformly selected from the Contention Window (CW ). This contention window is dynamically controlled by the Binary Exponential Backoff (BEB) algorithm. The BEB scheme, as shown in some studies in the literature, suffers from a fairness problem and low throughput under high traffic load. In this paper, we propose a new backoff algorithm, termed the Linear/Multiplicative Increase and Linear Decrease (LMILD) backoff algorithm, for use with the IEEE 802.11 Distributed Coordination Function. …

Web Usage Mining: Algorithms And Results, Ee Peng Lim, Yew-Kwong Woon, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

No abstract provided.

Reading Over The Shoulder Of The Future At The Library Of Congress, Samuel Gerald Collins

Reconstruction: Studies in Contemporary Culture

[First paragraph]

It is 2003 and I am doing some research at the Library of Congress, the de facto national library for the United States and the largest library in the world. Next to me sit some articles I've printed off of online journals on the Defense Advanced Research Project Agency's Total Information Awareness Project, a plan, still in its formative stage, to throw a panopticon net of surveillance across the United States through a combination of language translation technologies, data search and pattern recognition technologies, and advanced collaborative and decision support tools (DARPA). But I am also doing research …

Imagining The Performance Zone: Overcoming Ambiguity In Consumer Based Electronic Performance Support Systems, Jason Simons

Theses : Honours

The locus of performance support implementation was once the domain of large corporations where its principles offered an attractive alternative to traditional methods of training within the scope of contemporary business practices. Due to economies of scale the large corporations were able to build effective performance support through the precise identification of the PERFORMANCE ZONE. This zone is created through the defining of the three attributes of performance, 1) the nature of the worker, 2) the nature of the task, and 3) the type and amount of support needed. lncreasingly the principles of performance-centred design have been adopted within diverse …

Np-Hardness Of Cache Mapping, Zhiyuan Li, Rong Xu

Department of Computer Science Technical Reports

No abstract provided.

A Toolkit For Xml-Based And Process-Oriented Application Integration, Volker Münch

Theses

Systems integration is hard work; different architectures with different interfaces and an innumerable amount of Legacy applications with non-standard interfaces exist. However the needs to meet changing business requirements and to implement faster and optimised procedures within an enterprise and in cooperation with other external enterprises mean that there is a continuing demand for such integration strategies and products. Integration was often an activity separate from system development and could not be accomplished without re-involving system designers and developers. Such a process is therefore inefficient and costly. This thesis proposes a process-oriented integration strategy that combines the tasks of integration …

Pperfgrid: A Grid Services-Based Tool For The Exchange Of Heterogeneous Parallel Performance Data, John Jared Hoffman

Dissertations and Theses

This thesis details the approach taken in developing PPerfGrid. Section 2 discusses other research related to this project. Section 3 provides general background on the technologies utilized in PPerfGrid, focusing on the components that make up the Grid services architecture. Section 4 provides a description of the architecture of PPerfGrid. Section 5 details the implementation of PPerfGrid. Section 6 presents tests designed to measure the overhead and scalability of the PPerfGrid application. Section 7 suggests future work, and Section 8 concludes the thesis.

Variable Rate Execution, Steve Goddard, Xin Liu

School of Computing: Technical Reports

We present a task model for adaptive real-time tasks in which a task’s execution rate requirements are allowed to change at any time. The model, variable rate execution (VRE), is an extension of the rate-based execution (RBE) model. We relax the constant execution rate assumption of canonical realtime task models by allowing both the worst case execution time (WCET) and the period to be variable. The VRE model also supports tasks joining and leaving the system at any time. Another advantage of the new task model is that the exact execution rate need not be known for soft real-time or …

Toward Building A Social Robot With An Emotion-Based Internal Control, Andreas Marpaung

Electronic Theses and Dissertations

In this thesis, we aim at modeling some aspects of the functional role of emotions on an autonomous embodied agent. We begin by describing our robotic prototype, Cherry--a robot with the task of being a tour guide and an office assistant for the Computer Science Department at the University of Central Florida. Cherry did not have a formal emotion representation of internal states, but did have the ability to express emotions through her multimodal interface. The thesis presents the results of a survey we performed via our social informatics approach where we found that: (1) the idea of having emotions …

Xml In Computational Science, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

In this first article in a series about XML in computational science, I present some background and lightweight examples of XML usage, describe some XML component frameworksalong with their purpose and applicability to computational science, and discuss some technical obstacles to overcome for the language to be taken seriously in computational science.

Integrating Experiments And Simulators Into A Distributed E-Learning Environment, Frank Koehler

Theses

New information and communication technologies have emerged in the last few years which have made an impact on learning at all levels. At universities, the spectrum of learning support ranges from enriching traditional lectures and courses with multi- media elements to complete web-based interactive learning environments. A special aspect based on the new media technologies is learning within model worlds by use of simulations or real-life experiments. There are normally no links between these applications and the learning content, so it is impossible to tap the full potential of these applications. Research activities in the area of e-learning underline the …

Virtual Personal Assistants In A Pervasive Computing World, John F. Bradley, Brian R. Duffy, Gregory O'Hare, Alan Martin, Bianca Schoen-Phelan

Conference papers

Computing paradigms are constantly evolving-from mainframe to desktop, and on to ubiquitous computing. With a wide variety of devices, each with varying constraints, it would be quite difficult to develop services that would operate in a uniform manner across all platforms. With this in mind we offer an agent based solution. Agent attributes of autonomy, adaptability and mobility make them highly suitable for use in pervasive computing environments. Agent Chameleons illustrates a framework for Virtual Personal Assistants (VPA) for the information age. This paper briefly outlines some of the technologies and concepts that underpin the functionality of a VPA.

An Agent-Based Approach To Adaptive Navigational Support Within 3d-Environments, Bianca Schoen-Phelan, Gregory O'Hare, Brian Duffy, Alan Martin

Conference papers

his paper investigates mechanisms and approaches to assisting user navigation and exploration within 3-dimensional worlds. Specifically it advocates the deployment of an agentbased approach to dynamic system assistance and intervention. A performance equation is presented in a basic and an extended version, which is used to activate system interventions and to evaluate user performances online and offline. The measure is derived via a light-weight computationally inexpensive masking approach. We describe some navigation experiments and the results of navigational intervention via the damping of the sensitivity of the navigational keys. Interestingly the navigational assistance does not yield improvements in the subjects’ …

Interactive Dna Sequence And Structure Design For Dna Nanoapplications, Mingjun Zhang, Chaman Sabharwal, Weimin Tao, Tzyh-Jong Tarn, Ning Xi, Guangyong Li

Computer Science Faculty Research & Creative Works

DNA sequence and structure design is very important for DNA nanoapplications. A computer-aided design tool is needed for exploring DNA sequence and structure of interests before experimental synthesis, which is a time- and labor-consuming process. In this paper, an interactive DNA sequence and structure design software tool called DNA shop is proposed and implemented. The visualization tool can generate DNA structures by specifying, selecting, and moving DNA sequences around and display corresponding structures. Using the tool, DNA sequence and structure can be visually inspected in three-dimensional space before experimental studies.

Interactive Dna Sequence And Structure Design For Dna Nanotechnology And Dna Computation, Mingjun Zhang, Chaman Sabharwal, Weimin Tao, Tzyh-Jong Tarn, Ning Xi, Guangyong Li

Computer Science Faculty Research & Creative Works

DNA sequence and structure design are very important for DNA nanotechnology and DNA computation. A computer aided design tool is needed for exploring DNA sequence and structure of interests before experimental synthesis, which is a very time and labor consuming process. In this paper, an interactive DNA sequence and structure design software tool called DNA shop is proposed and implemented.

Micro Spies, Georae W. Zobrist

Computer Science Faculty Research & Creative Works

No abstract provided.

Optimisation Of John The Ripper In A Clustered Linux Environment, Christian Frichot

Theses : Honours

To aid system administrators in enforcing strict password policies, the use of password cracking tools such as Cisilia (C.I.S.I.ar, 2003) and John the Ripper (Solar Designer, 2002), have been employed as software utilities to look for "weak" passwords. John the Ripper (JtR) attempts to crack the passwords by using a dictionary, brute-force or "other" mode of attack. The computational intensity of cracking passwords has led to the utilisation of parallel-processing environments to increase the speed of the password-cracking task. Parallel-processing environments can consist of either single systems with multiple processors, or a collection of separate computers working together as a …

Exploring The Possibilities Of Three Dimensional Image Manipulations On Mobile Devices, Thanuja Nuwan Hettiarachchi

Theses : Honours

With the introduction of more powerful mobile microprocessors and colour screen technology, complex image manipulations on various mobile devices such as mobile phones and handheld devices have become a reality. As a consequence of these improvements, there has been an increasing demand by users for interactive computer games which produce complex graphics by utilizing these advanced hardware technologies. Three dimensional (3D) graphics have been used to produce realistic interactive imaging for computer games during recent years. Java, through its mobile device programming platform, provides the framework for such complex image manipulations in computer games deployed on Java compatible mobile devices. …

Qos Routing Optimization Strategy Using Genetic Algorithm In Optical Fiber Communication Networks, Zhaoxia Wang, Zengqiang Chen, Zhuzhi Yuan

Research Collection School Of Computing and Information Systems

This paper describes the routing problems in optical fiber networks, defines five constraints, induces and simplifies the evaluation function and fitness function, and proposes a routing approach based on the genetic algorithm, which includes an operator [OMO] to solve the QoS routing problem in optical fiber communication networks. The simulation results show that the proposed routing method by using this optimal maintain operator genetic algorithm (OMOGA) is superior to the common genetic algorithms (CGA). It not only is robust and efficient but also converges quickly and can be carried out simply, that makes it better than other complicated GA.

Resource Harvesting Within The Oai-Pmh Framework, Herbert Van De Sompel, Michael L. Nelson, Carl Lagoze, Simeon Warner

Computer Science Faculty Publications

Motivated by preservation and resource discovery, we examine how digital resources, and not just metadata about resources, can be harvested using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). We review and critique existing techniques for identifying and gathering digital resources using metadata harvested through the OAI-PMH. We introduce an alternative solution that builds on the introduction of complex object formats that provide a more accurate way to describe digital resources. We argue that the use of complex object formats as OAI-PMH metadata formats results in a reliable and attractive approach for incremental harvesting of resources using the OAI-PMH.

Interworking Methodologies For Dcom And Corba., Edwin Kraus

Electronic Theses and Dissertations

The DCOM and CORBA standards provide location-transparent access to network-resident software through language independent object interfaces. Although the two standards address similar problems, they do so in incompatible ways: DCOM clients cannot use CORBA objects, and CORBA clients cannot utilize DCOM objects, due to incompatible object system infrastructures.

This thesis investigates the performance of bridging tools to resolve the incompatibilities between DCOM and CORBA, in ways that allow clients to cross object system boundaries. Two kinds of tools were constructed and studied: tools that bind clients to services at compile time, and tools that support dynamic client-server bindings. Data developed …

A Study Of The Suitability Of Irobex For High-Speed Exchange Of Large Data Objects, Casey T. Deccio, Joseph Ekstrom, Charles D. Knutson, D. Ryan Partridge, Kevin B. Tew

Faculty Publications

This paper demonstrates that careful tuning of the OBEX and IrLAP negotiated parameters allows OBEX to scale well for use with large data objects and high transmission rates. Due to the substantial time overhead inherent in link turnarounds, minimizing turnarounds during the transmission of a large object helps to maximimize link efficiency. The IrLAP window size and OBEX packet size significantly impact the number of required turnarounds during the transmission of a large object. When these parameters are properly tuned, maximum throughput can be achieved, and OBEX performs efficiently at high data rates.

Semantic (Web) Technology In Action: Ontology Driven Information Systems For Search, Integration, And Analysis, Amit P. Sheth, Cartic Ramakrishnan

Kno.e.sis Publications

Semantics is seen as the key ingredient in the next phase of the Web infrastructure as well as the next generation of information systems applications. In this context, we review some of the reservations expressed about the viability of the Semantic Web. We respond to these by identifying a Semantic Technology that supports the key capabilities also needed to realize the Semantic Web vision, namely representing, acquiring and utilizing knowledge. Given that scalability is a key challenge, we briefly review our observations from developing three classes of real world applications and corresponding technology components: search/browsing, integration, and analytics. We distinguish …

Semantic Web Processes: Semantics Enabled Annotation, Discovery, Composition, And Orchestration Of Web Scale Processes, Jorge Cardoso, Amit P. Sheth

Kno.e.sis Publications

This tutorial deals with the evolution of inter- Enterprise and Web scale process to support e-commerce and e-services. It taps into the promises of two of the hottest R&D and technology areas: Web services and the Semantic Web. It presents how applying semantics to each of the steps in the Semantic Web Process lifecycle can help address critical issues in reuse, integration and scalability.

Viewer-Based Directional Querying For Mobile Applications, Keith Gardiner, James Carswell

Conference papers

With the steady and fast advancements in the integration of geographic information systems and mobile location-based services, interest in exploiting this technology for Cultural Heritage (CH) data sharing has become apparent. In this area there has been an increasing need to integrate positional information with non-positional data and add a spatial dimension to the definition of a users “context”. In this paper we describe an implementation of a viewer-based directional query processor that operates on an Oracle Spatial database. The spatial position and orientation are taken from the viewer’s perspective. Using this frame of reference a view-port is defined in …

Structuring Lecture Videos For Distance Learning Applications, Chong-Wah Ngo, Feng Wang, Ting-Chuen Pong

Research Collection School Of Computing and Information Systems

This paper presents an automatic and novel approach in structuring and indexing lecture videos for distance learning applications. By structuring video content, we can support both topic indexing and semantic querying of multimedia documents. In this paper, our aim is to link the discussion topics extracted from the electronic slides with their associated video and audio segments. Two major techniques in our proposed approach include video text analysis and speech recognition. Initially, a video is partitioned into shots based on slide transitions. For each shot, the embedded video texts are detected, reconstructed and segmented as high-resolution foreground texts for commercial …

Validating And Refining Clusters Via Visual Rendering, Keke Chen, Ling Liu

Kno.e.sis Publications

The automatic clustering algorithms are known to work well in dealing with clusters of regular shapes, e.g. compact spherical/elongated shapes, but may incur higher error rates when dealing with arbitrarily shaped clusters. Although some efforts have been devoted to addressing the problem of skewed datasets, the problem of handling clusters with irregular shapes is still in its infancy, especially in terms of dimensionality of the datasets and the precision of the clustering results considered. Not surprisingly, the statistical indices works ineffective in validating clusters of irregular shapes, too. We address the problem of clustering and validating arbitrarily shaped clusters with …

Semantic E-Workflow Composition, Jorge Cardoso, Amit P. Sheth

Kno.e.sis Publications

Systems and infrastructures are currently being developed to support Web services. The main idea is to encapsulate an organization's functionality within an appropriate interface and advertise it as Web services. While in some cases Web services may be utilized in an isolated form, it is normal to expect Web services to be integrated as part of workflow processes. The composition of workflow processes that model e-service applications differs from the design of traditional workflows, in terms of the number of tasks (Web services) available to the composition process, in their heterogeneity, and in their autonomy. Therefore, two problems need to …

Towards (Semi-) Automatic Generation Of Bio-Medical Ontologies, Vipul Kashyap, Cartic Ramakrishnan, Thomas Rindflesch

Kno.e.sis Publications

The design and construction of domain specific ontologies and taxonomies requires allocation of huge resources in terms of cost and time. These efforts are human intensive and we need to explore ways of minimizing human involvement and other resources. In the biomedical domain, we seek to leverage resources such as the UMLS1 Metathesaurus and NLP-based applications such as MetaMap2 in conjunction with statistical clustering techniques, to (partially) automate the process. This is expected to be useful to the team involved in developing MeSH and other biomedical taxonomies to identify gaps in the existing taxonomies, and to be able to quickly …

Content-Aware Authentication Of Motion Jpeg2000 Stream In Lossy Networks, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

Stream authentication schemes (SAS) aim to achieve effective authentication of multicast streams over lossy networks. Almost all the existing SASs is designed for stream data integrity protection only. In this paper, we argue that content integrity protection is more important than data integrity to human users. We present a content-aware SAS in motion JPEG2000 streaming. In our scheme, a chunk of JPEG2000 codestreams is encapsulated into a block of packets using multiple description coding (MDC). Our MDC exploits the inherent structure of motion JPEG2000 codestreams and is used to preserve the semanteme/content of the stream over lossy networks. To achieve …