Digital Commons Network^™

Network Simulation And Performance Evalution Of Ip Multicast Using Pim-Dm In Umjanetsim, Jui Hiangh Teoh

Student Works (2000-2009)

The demand for multicast capabilities in IP networks is growing very rapidly. New applications that take advantage of IP Multicast are being introduced constantly. Therefore, IP Multicast is regarded as one of the most important technologies in IP networks today. This dissertation focuses on the simulation and performance evaluation of IP Multicast using Protocol Independent Multicast- Dense Mode (PIM-OM) as the multicast routing protocol. The simulation is executed in a network simulator named UMJaNetSim, where custom components are built in order to simulate IP Multicast. First, the advantages and applications of IP Multicast, multicast addressing, Internet Group Management Protocol (IGMP), …

Mpls Vpn Simulation Using Mp-Ibgp, Tan Fong Ang

Student Works (2000-2009)

As Internet traffic continues to increase, companies are demanding greater speeds and better services to disseminate information to their customers, partners and employees. In order to provide reliable services and to support a variety of secure communications among a wide range of locations, Multiprotocol Label Switching Virtual Private Network (MPLS VPN) has been introduced. MPLS is an emerging technology that aims to address many of the existing issues associated with packet forwarding in today's internetworking environment. Whereas, VPN provides secure private connections through public infrastructure amongst multiple locations. MPLS­ based VPN provides isolation. security, simplified routing, easier provisioning as well …

Performance Evaluation Of Hybrid Coding Of Images Using Wavelet Transform And Predictive Coding, S. R. Subramanya, Chaman Sabharwal

Computer Science Faculty Research & Creative Works

Image compression techniques are necessary for the storage of huge amounts of digital images using reasonable amounts of space, and for their transmission with limited bandwidth. Several techniques such as predictive coding, transform coding, subband coding, wavelet coding, and vector quantization have been used in image coding. While each technique has some advantages, most practical systems use hybrid techniques which incorporate more than one scheme. They combine the advantages of the individual schemes and enhance the coding effectiveness. This paper proposes and evaluates a hybrid coding scheme for images using wavelet transforms and predictive coding. The performance evaluation is done …

Workstation Clusters For Parallel Computing, J. Stone, Fikret Erçal

Computer Science Faculty Research & Creative Works

Workstation clusters have become an increasingly popular alternative to traditional parallel supercomputers for many workloads requiring high performance computing. The use of parallel computing for scientific simulations has increased tremendously in the last ten years, and parallel implementations of scientific simulation codes are now in widespread use. There are two dominant parallel hardware/software architectures in use today: distributed memory, and shared memory. Systems implementing shared memory provide cooperating processes with a shared memory address space that can be accessed by all processors. In shared memory systems, parallel processing occurs through the use of shared data structures, or through emulation of …

Fast Incremental Crc Updates For Ip Over Atm Networks, Florian Braun, Marcel Waldvogel

All Computer Science and Engineering Research

In response to the increasing network speeds, many operations in IP routers and similar devices are being made more efficient. With the advances in other areas of packet processing, the verification and regeneration of cyclic redundancy check (CRC) codes of the data link layer is likely to become a bottleneck in the near future. In this paper, we present a mechanism to defer CRC verification without compromising reliability. This opens the possibility of incremental updates of the CRC. We introduce a new high-speed technique and present efficient implementation, speeding up CRC processing by a factor of 15. Although the paper …

Rad Module Infrastructure Of The Field-Programmable Port Extender (Fpx) Version 2.0, David E. Taylor, John W. Lockwood, Naji Naufel

All Computer Science and Engineering Research

The Field-programmable Port eXtender (FPX) provides dynamic, fast, and flexible mechanisms to process data streams at the ports of the Washington University Gigabit Switch (WUGS-20). In order to facilitate the design and implementation of portable hardware modules for the Reprogrammable Application Device (RAD) on the FPX board, infrastructure components have been developed. These components abstract application module designers from device-specific timing specifications of off-chip memory devices, as well as processing system-level control cells. This document describes the design and internal functionality of the infrastructure components and is intended as a reference for future component revisions and additions. Application module designers …

Network Abstractions For Context-Aware Mobile Computing, Gruia-Catalin Roman, Christine Julien, Qingfeng Huang

All Computer Science and Engineering Research

Context-Aware computing is characterized by the ability of a software system to continuously adapt its behavior to a changing environment over which it has little or no control. Previous work along these lines presumed a rather narrow definition of context, one that was centered on resources immediately available to the component in question, e.g., communication bandwidth, physical location, etc. This paper explores context-aware computing in the setting of ad hoc networks consisting of numerous mobile hosts that interact with each other opportunistically via transient wireless interconnections. We extend the context to encompass awareness of an entire neighborhood within the ad …

Indra: A Distributed Approach To Network Intrusion Detection And Prevention, Qi Zhang, Ramaprabhu Janakiraman

All Computer Science and Engineering Research

While advances in computer and communications technology have made the network ubiquitous, they ahve also rendered networked systems vulnerable to malicious attacks orchestrated from a distance. These attacks, usually called cracker attacks or intrusions, start with crackers infiltrating a network through a vulnerable host and then going on to launch further attacks. Crackers depend on increasingly sophisticated techniques like using distributed attack sources. On the other hand, software that guards against them remains rooted in traditional centralized techniques, presenting an easily-targetable single point of failure. Scalable, distributed network intrusion prevention software is sorely needed. We propose Indra - a distributed …

The Need For Information And Communication Technology (Ict) Literacy Among Lower Secondary Students, Sri Kumaran Rajendran

Student Works (2000-2009)

The purpose of this study is to determine the need for ICT literacy among lower secondary students. The study was designed to answer the following objectives: 1) Whether there is any significance difference between the need for a structured ICT syllabus and that of informal learning of ICT through friends, reading materials, parents, CD-ROM, and interest. 2) To gauge the interest shown towards ICT related activities after undergoing structured ICT syllabus. The study focused on two secondary schools in the Petaling District of Selangor. A questionnaire was distributed to a total 300 student from Form One, Two, and Three of …

Language Support For Morton-Order Matrices, David S. Wise, Gregory A. Alexander, Jeremy D. Frens

University Faculty Publications and Creative Works

The uniform representation of 2-dimensional arrays serially in Morton order (or Ee Cyrillic sign order) supports both their iterative scan with cartesian indices and their divide-and-conquer manipulation as quaternary trees. This data structure is important because it relaxes serious problems of locality and latency, and the tree helps to schedule multi-processing. Results here show how it facilitates algorithms that avoid cache misses and page faults at all levels in hierarchical memory, independently of a specific runtime environment. We have built a rudimentary C-to-C translator that implements matrices in Morton-order from source that presumes a row-major implementation. Early performance from LAPACK's …

[Introduction To] Basic Java Programming: A Laboratory Approach, Lewis Barnett

Bookshelf

For first- and second-year undergraduates, an introduction to programming with Java, an object-oriented programming language that is a popular choice for Web applications. Kent and Barnett (U. of Richmond) introduce algorithms and problem-solving approaches that are important to programming general.

Machine Learning In Euchre: A Comparison Of Techniques, Michael J. Holmes

Dissertations and Theses @ UNI

This study compares the effectiveness of inductive and analytical learning techniques for a specific type of problem. The set of problems has a large number of parameter combinations as inputs, and a small set of possible output solutions. The card game, Euchre, was the basis for research. Four algorithms were used for comparison. Two were variants of induction using decision tree learning, and the other two used variants of explanation-based learning, an analytical approach. The example data were gathered from human players, along with one set of random, "noisy" data. These data were then used as training sets for the …

Incorporating Window-Based Passage-Level Evidence In Document Retrieval, Wensi Xi, Richard Xu-Rong, Christopher Soo Guan Khoo, Ee Peng Lim

Research Collection School Of Computing and Information Systems

This study investigated whether document retrieval can be improved if documents are divided into smaller sub-documents or passages and the retrieval score for these passages are incorporated in the final retrieval score for the whole document. The documents were segmented by sliding a window of a certain size across the document and extracting the words displayed each time the window stopped. A retrieval score was calculated for each of the passages extracted and the highest score obtained by a passage of that size was taken as the document’s passage-level score for that window size. A range of window sizes was …

A Framework For Performance And Value Assessment Of E-Business Systems In Corporate Travel Distribution, A.M. Chircu, Robert J. Kauffman

Research Collection School Of Computing and Information Systems

This chapter proposes and illustrates a framework that the authors call the value life cycle for e-commerce systems. Based on recent research results that relate to technology investments in the corporate travel industry and related theoretical and empirical perspectives, the authors lay out the corporate travel e-commerce system solutions value life cycle. The perspective involves estimating the maximum value that that an organization can obtain by implementing an e-commerce system in a specific industry and competitive environment. It also considers multiple factors that act as value contingencies for the implementation process. These create barriers to value accrual and to …

Buckets: Smart Objects For Digital Libraries, Michael L. Nelson

Computer Science Faculty Publications

Current discussion of digital libraries (DLs) is often dominated by the merits of the respective storage, search and retrieval functionality of archives, repositories, search engines, search interfaces and database systems. While these technologies are necessary for information management, the information content is more important than the systems used for its storage and retrieval. Digital information should have the same long-term survivability prospects as traditional hardcopy information and should be protected to the extent possible from evolving search engine technologies and vendor vagaries in database management systems. Information content and information retrieval systems should progress on independent paths and make limited …

External Memory Algorithms For Factoring Sparse Matrices, Florin Dobrian

Computer Science Theses & Dissertations

We consider the factorization of sparse symmetric matrices in the context of a two-layer storage system: disk/core. When the core is sufficiently large the factorization can be performed in-core. In this case we must read the input, compute, and write the output, in this sequence. On the other hand, when the core is not large enough, the factorization becomes out-of-core, which means that data movement and computation must be interleaved.

We identify two major out-of-core factorization scenarios: read-once/write-once (R1/W1) and read-many/write-many (RM/WM). The former requires minimum traffic, exactly as much as the in-core factorization: reading the input and writing the …

Seaway: A Multi-Agent Decision-Support System For Naval Expeditionary Logistic Operations, Anthony Wood, Kym Jason Pohl, Justin Crawford, Mark Lai, John Fanshier, Ken Cudworth, Tom Tate, Hisham Assal, Shawn Pan, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This report describes work performed by CDM Technologies Inc. in conjunction with the Collaborative Agent Design (CAD) Research Center of California Polytechnic State University (Cal Poly), San Luis Obispo, for the Office of Naval Research (ONR), on the SEAWAY experimental system for planning, gaming and executing maritime logistic operations from a sea base. SEAWAY incorporates three fundamental concepts that distinguish it from existing (i.e., legacy) command and control applications. First, it is a collaborative system in which computer-based agents assist human operators by monitoring, analyzing and reasoning about events in near real-time. Second, SEAWAY includes an ontological model of the …

Software Quality Function Deployment, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

Any product development involves projecting its potential success in achieving its functional and commercial goals. Better quality designs that match customer needs and preferences and integrate other lifecycle issues early in the software development process are more likely to be competitive. Thus, there is significant concern in industry about quality product design, which is addressed by quality function deployment (QFD). QFD uses matrices to organize and relate pieces of data to each other. These matrices are often combined to form a basic tool of QFD, called a House of Quality (HoQ). QFD was developed in the Kobe shipyards as a …

Control Challenges In Multi-Level Adaptive Video Streaming, Dylan Mcnamee, Charles Krasic, Kang Li, Ashvin Goel, Erik Walthinsen, David Steere, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Streaming video is one of the fastest-growing applications of the Internet. The Internet’s diversity and dynamism demands that video streams adapt to ensure maximum quality at all times. This paper describes the control challenges we have encountered in the Quasar project’s “multi-level” adaptive streaming video player. We first describe the framework and environment of the player. This framework uses software feedback to control resource allocation as well as the quality of media delivery. We present the control challenges raised by our framework, which include horizontal and vertical feedback composition, difficult to model systems, and unpredictable, non-linear actuators. We describe some …

Reconstructing Ancient Egyptian Tombs, Hany Farid

Computer Science Technical Reports

From the pyramids of Giza to the tombs of Thebes (modern Luxor), ancient Egypt's glorious history has produced remarkable architecture. Sadly, the nearly four million yearly tourists have taken a heavy toll on many of these ancient structures. Of particular concern are many of the tombs located opposite to Luxor on the western bank of the Nile. Digital reconstruction of these tombs has the potential to help document and preserve these important historical structures. Photographing and reconstruction of these tombs poses new and unique problems that this paper begins to address. Techniques for removing image distortions, recovering 3-D shape, and …

Bayes Optimal Metasearch: A Probabilistic Model For Combining The Results Of Multiple Retrieval Systems, Javed A. Aslam, Mark Montague

Computer Science Technical Reports

We introduce a new, probabilistic model for combining the outputs of an arbitrary number of query retrieval systems. By gathering simple statistics on the average performance of a given set of query retrieval systems, we construct a Bayes optimal mechanism for combining the outputs of these systems. Our construction yields a metasearch strategy whose empirical performance nearly always exceeds the performance of any of the constituent systems. Our construction is also robust in the sense that if ``good'' and ``bad'' systems are combined, the performance of the composite is still on par with, or exceeds, that of the best constituent …

Collaborative Model And Algorithms For Supporting Real-Time Distribution Logistics Systems, Hoong Chuin Lau, Qi Zhang Liu

Research Collection School Of Computing and Information Systems

We study a complex optimization problem that arises due to an emerging trend in distribution logistics. The problem involves the integration of an inventory management problem and the vehicle routing problem with time windows, both of which are known to be NP-hard. We describe a collaborative approach to solve this problem in real-time. The novelty of our approach lies in the tight algorithmic integration between two sub-problems, and suggests an elegant scheme to deal with other integrated optimization problems of the same nature. For first sub-problem, we will present two algorithms: a complete mathematical model integrating integer programming with constraint …

Computational Geometry Column 40, Joseph O'Rourke

Computer Science: Faculty Publications

It has recently been established by Below, De Loera, and Richter-Gebert that finding a minimum size (or even just a small) triangulation of a convex polyhedron is NP-complete. Their 3SAT-reduction proof is discussed.

Simulation Of Instability Onset In A Gas Turbine, S. Fleeter, Elias N. Houstis, John R. Rice, C. Zhou

Department of Computer Science Technical Reports

No abstract provided.

A Proactive Approach To Distributed Dos Prevention Using Route-Based Packet Filtering, Kihong Park, Heejo Lee

Department of Computer Science Technical Reports

No abstract provided.

Impact Of Tile-Size Selection For Skewed Tiling, Yonghong Song, Zhiyuan Li

Department of Computer Science Technical Reports

No abstract provided.

Combinatorial Approach To Planar Non-Colliding Robot Arm Motion Planning, Ileana Streinu

Computer Science: Faculty Publications

We propose a combinatorial approach to plan non-colliding motions for a polygonal bar-and-joint framework. Our approach yields very efficient deterministic algorithms for a category of robot arm motion planning problems with many degrees of freedom, where the known general roadmap techniques would give exponential complexity. It is based on a novel class of one-degree-of-freedom mechanisms induced by pseudo triangulations of planar point sets, for which we provide several equivalent characterization and exhibit rich combinatorial and rigidity theoretic properties. The main application is an efficient algorithm for the Carpenter's Rule Problem: convexify a simple bar-and-joint planar polygonal linkage using only non …

Knowledge Discovery As An Aid To Organizational Creativity, Keng Siau

Research Collection School Of Computing and Information Systems

Computers can play an important role in the creative process. With the abundance of data and increasing speed of computers, creativity can now be stimulated and enhanced with knowledge mined from available data. The process is known as knowledge discovery or data mining. Knowledge discovery is the process of discovering interesting associations among data in the database. Users in the creativity process can feed on the discovered associations to generate creative solutions. The objective of this paper is to present knowledge discovery as an aid to creativity. The paper first presents the concept of knowledge discovery and then discusses the …

Generalized Tcp Congestion Avoidance And Its Effect On Bandwidth Sharing And Variability, Archan Misra, John Baras, Teunis Ott

Research Collection School Of Computing and Information Systems

To model possible suggested changes in TCP window adaptation in response to randomized feedback, such as ECN (explicit congestion notification), we formulate a generalized version of the TCP congestion avoidance algorithm. We first consider multiple such generalized TCP flows sharing a bottleneck buffer under the assured service model and use a fixed point technique to obtain the mean window sizes and throughputs for the TCP flows, To further study how changes in the adaptation algorithm affect the variability in the throughput, we use an analytical-cum-numerical technique to derive the window distribution (and related statistics) of a single generalized flow under …

An Efficient And Practical Scheme For Privacy Protection In E-Commerce Of Digital Goods, Feng Bao, Robert H. Deng, Peirong Feng

Research Collection School Of Computing and Information Systems

It is commonly acknowledged that customers’ privacy in electronic commerce should be well protected. The solutions may come not only from the ethics education and legislation, but also from cryptographic technologies. In this paper we propose and analyze a privacy protection scheme for e-commerce of digital goods. The scheme takes cryptography as its technical means to realize privacy protection for online customers. It is efficient in both computational cost and communication cost. It is very practical for real e-commerce systems compared with previous solutions. The cryptographic technique presented in this paper is rather simple. But the scheme has great application …