Digital Commons Network^™

Sclope: An Algorithm For Clustering Data Streams Of Categorical Attributes, Kok-Leong Ong, Wenyuan Li, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Clustering is a difficult problem especially when we consider the task in the context of a data stream of categorical attributes. In this paper, we propose SCLOPE, a novel algorithm based on CLOPE's intuitive observation about cluster histograms. Unlike CLOPE however, our algorithm is very fast and operates within the constraints of a data stream environment. In particular, we designed SCLOPE according to the recent CluStream framework. Our evaluation of SCLOPE shows very promising results. It consistently outperforms CLOPE in speed and scalability tests on our data sets while maintaining high cluster purity; it also supports cluster analysis that other …

A Two-Level Framework For Coalition Formation Via Optimization And Agent Negotiation, Hoong Chuin Lau, Lei Zhang

Research Collection School Of Computing and Information Systems

We present a two-level coalition formation approach based on a centralized optimization model on the upper level, and a distributed agent-negotiation model on the lower level. This approach allows us to balance agent self-interests against a high joint utility. Experimental results show that the two-level coalition formation mechanism will increase not only the overall utility of the coalition, but also the individual utility of most participating agents. The results also suggest it is better for the agents to be partially cooperative rather than either fully cooperative or self-interested in our setting.

Run-Time Modification Of The Class Hierarchy In A Live Java Development Environment, Joel R. Brandt, Kenneth J. Goldman

All Computer Science and Engineering Research

Class hierarchy design is central to object-oriented software development. However, it is sometimes difficult for developers to anticipate all the implications of a design until implementation is underway. To support experimentation with different designs, we extend prior work on live development environments to allow run-time modification of the class hierarchy. The result is a more fluid object-oriented development process, in which immediate feedback from the executing program can be used to guide hierarchy design. This paper presents a framework and developer support for run-time modification of class inheritance relations in JPie, a live visual programming environment for Java. Most notably, …

Pattern Search Ranking And Selection Algorithms For Mixed-Variable Optimization Of Stochastic Systems, Todd A. Sriver

Theses and Dissertations

A new class of algorithms is introduced and analyzed for bound and linearly constrained optimization problems with stochastic objective functions and a mixture of design variable types. The generalized pattern search (GPS) class of algorithms is extended to a new problem setting in which objective function evaluations require sampling from a model of a stochastic system. The approach combines GPS with ranking and selection (R&S) statistical procedures to select new iterates. The derivative-free algorithms require only black-box simulation responses and are applicable over domains with mixed variables (continuous, discrete numeric, and discrete categorical) to include bound and linear constraints on …

Visual Unified Modeling Language For The Composition Of Scenarios In Modeling And Simulation Systems, Daniel E. Swayne

Theses and Dissertations

The Department of Defense uses modeling and simulation systems in many various roles, from research and training to modeling likely outcomes of command decisions. Simulation systems have been increasing in complexity with the increased capability of low-cost computer systems to support these DOD requirements. The demand for scenarios is also increasing, but the complexity of the simulation systems has caused a bottleneck in scenario development due to the limited number of individuals with knowledge of the arcane simulator languages in which these scenarios are written. This research combines the results of previous AFIT efforts in visual modeling languages to create …

Robust Classification Of Event-Related Potential For Brain-Computer Interface, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

We report the implementation of a text input application (speller) based on the P300 event related potential. We obtain high accuracies by using an SVM classifier and a novel feature. These techniques enable us to maintain fast performance without sacrificing the accuracy, thus making the speller usable in an online mode. In order to further improve the usability, we perform various studies on the data with a view to minimizing the training time required. We present data collected from nine healthy subjects, along with the high accuracies (of the order of 95% or more) measured online. We show that the …

The Changing Usage Of A Mature Campus-Wide Wireless Network, Tristan Henderson, David Kotz, Ilya Abyzov

Dartmouth Scholarship

Wireless Local Area Networks (WLANs) are now commonplace on many academic and corporate campuses. As “Wi-Fi” technology becomes ubiquitous, it is increasingly important to understand trends in the usage of these networks. \par This paper analyzes an extensive network trace from a mature 802.11 WLAN, including more than 550 access points and 7000 users over seventeen weeks. We employ several measurement techniques, including syslogs, telephone records, SNMP polling and tcpdump packet sniffing. This is the largest WLAN study to date, and the first to look at a large, mature WLAN and consider geographic mobility. We compare this trace to a …

Ao2p: Ad-Hoc On-Demand Position-Based Private Routing Protocol, Xiaoxin Wu, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Towards Personalised Web Intelligence, Ah-Hwee Tan, Hwee-Leng Ong, Hong Pan, Jamie Ng, Qiu-Xiang Li

Research Collection School Of Computing and Information Systems

The Flexible Organizer for Competitive Intelligence (FOCI) is a personalised web intelligence system that provides an integrated platform for gathering, organising, tracking, and disseminating competitive information on the web. FOCI builds personalised information portfolios through a novel method called User-Configurable Clustering, which allows a user to personalise his/her portfolios in terms of the content as well as the organisational structure. This paper outlines the key challenges we face in personalised information management and gives a detailed account of FOCI’s underlying personalisation mechanism. For a quantitative evaluation of the system’s performance, we propose a set of performance indices based on information …

A Qualitative Investigation On Consumer Trust In Mobile Commerce, Keng Siau, Hong Sheng, Fiona Fui-Hoon Nah, Sidney A. Davis

Research Collection School Of Computing and Information Systems

Mobile commerce represents a significant development in e-commerce, offering accessibility, ubiquity, mobility, and localisation to users. Despite the potential of mobile commerce, trust is a major obstacle in its adoption and development. Many consumers feel uncomfortable with the idea of conducting commerce over wireless, hand-held devices. The focus of this research is to understand trust in mobile commerce and to identify factors that are important for trust development. The research builds on Siau and Shen's framework which depicts two key factors influencing trust in mobile commerce. This research not only validates and expands on the existing framework, but also provides …

Heterogeneous Self-Reconfiguring Robotics, Robert Charles Fitch

Dartmouth College Ph.D Dissertations

Self-reconfiguring (SR) robots are modular systems that can autonomously change shape, or reconfigure, for increased versatility and adaptability in unknown environments. In this thesis, we investigate planning and control for systems of non-identical modules, known as heterogeneous SR robots. Although previous approaches rely on module homogeneity as a critical property, we show that the planning complexity of fundamental algorithmic problems in the heterogeneous case is equivalent to that of systems with identical modules. Primarily, we study the problem of how to plan shape changes while considering the placement of specific modules within the structure. We characterize this key challenge in …

Creating And Detecting Doctored And Virtual Images: Implications To The Child Pornography Prevention Act, Hany Farid

Computer Science Technical Reports

The 1996 Child Pornography Prevention Act (CPPA) extended the existing federal criminal laws against child pornography to include certain types of "virtual porn". In 2002, the United States Supreme Court found that portions of the CPPA, being overly broad and restrictive, violated First Amendment rights. The Court ruled that images containing an actual minor or portions of a minor are not protected, while computer generated images depicting a fictitious "computer generated" minor are constitutionally protected. In this report I outline various forms of digital tampering, placing them in the context of this recent ruling. I also review computational techniques for …

Jumpstarting Phylogenetic Analysis, Mark J. Clement, Keith A. Crandall, Kevin Seppi, Quinn O. Snell

Faculty Publications

When a new epidemic strikes, it is often important to determine the relationship between the current organism and others that have been successfully treated previously. The phylogenetic analysis problem generates the most likely family tree for a group of organisms based on DNA sequence data. This process can take a prohibitively long period of time with current algorithms. If trees resulting from prior searches are used to seed the search, correct trees can be found much more quickly. This jumpstarting algorithm can generate superior phylogenetic solutions much more quickly than existing algorithms.

Gentoo Linux: The Next Generation Of Linux, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

One of the reasons scientific programmers love Linux is its less-is-more philosophy. We can configure it to be anything from a desktop replacement with USB port support to a blade in a large SMP compute engine to a powerful Web server. Although Linux's market penetration in these various sectors remains to be seen, plenty of people are pumping resources into the Linux world. In this article, I?ll explain why Gentoo Linux (www.gentoolinux.org) is a good choice for scientists, and how its structure gives us the flexibility and ease of management we need.

On The Security Of The Lee-Hwang Group-Oriented Undeniable Signature Schemes, Guilin Wang, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

Undeniable signature is an intriguing concept introduced by Chaum and van Antwerpen at Crypto89. In 1999, Lee and Hwang presented two group-oriented undeniable signature schemes with a trusted center. Their schemes are natural generalizations of Chaums zero knowledge undeniable signature scheme proposed in 1990. However, we find that the Lee-Hwang schemes are insecure. In this paper, we demonstrate five effective attacks on their schemes: four of them are insider universal forgeries, in which one dishonest member (maybe colluding with a verifier) can get a valid signature on any chosen massage, and another attack allows a dishonest member to prevent honest …

Security Analysis Of Two Signcryption Schemes, Guilin Wang, Robert H. Deng, Dongjin Kwak, Sangjae Moon

Research Collection School Of Computing and Information Systems

Signcryption is a new cryptographic primitive that performs signing and encryption simultaneously, at a cost significantly lower than that required by the traditional signature-then-encryption approach. In this paper, we present a security analysis of two such schemes: the Huang-Chang convertible signcryption scheme, and the Kwak-Moon group signcryption scheme. Our results show that both schemes are insecure. Specifically, the Huang-Chang scheme fails to provide confidentiality, while the Kwak-Moon scheme does not satisfy the properties of unforgeability, coalition-resistance, and traceability.

A Spectroscopy Of Texts For Effective Clustering, Wenyuan Li, Wee-Keong Ng, Kok-Leong Ong, Ee Peng Lim

Research Collection School Of Computing and Information Systems

For many clustering algorithms, such as k-means, EM, and CLOPE, there is usually a requirement to set some parameters. Often, these parameters directly or indirectly control the number of clusters to return. In the presence of different data characteristics and analysis contexts, it is often difficult for the user to estimate the number of clusters in the data set. This is especially true in text collections such as Web documents, images or biological data. The fundamental question this paper addresses is: ldquoHow can we effectively estimate the natural number of clusters in a given text collection?rdquo. We propose to use …

A Development Framework For Rapid Metaheuristics Hybridization, Hoong Chuin Lau, M. K. Lim, W. C. Wan, S. Halim

Research Collection School Of Computing and Information Systems

While meta-heuristics are effective for solving large-scale combinatorial optimization problems, they result from time-consuming trial-and-error algorithm design tailored to specific problems. For this reason, a software tool for rapid prototyping of algorithms would save considerable resources. This work presents a generic software framework that reduces development time through abstract classes and software reuse, and more importantly, aids design with support of user-defined strategies and hybridization of meta-heuristics. Most interestingly, we propose a novel way of redefining hybridization with the use of the "request and response" metaphor, which form an abstract concept for hybridization. Different hybridization schemes can now be formed …

Shared-Storage Auction Ensures Data Availability, Hady W. Lauw, Siu-Cheung Hui, Edmund M. K. Lai

Research Collection School Of Computing and Information Systems

Most current e-auction systems are based on the client-server architecture. Such centralized systems provide a single point of failure and control. In contrast, peer-to-peer systems permit distributed control and minimize individual node and link failures' impact on the system. The shared-storage-based auction model described decentralizes services among peers to share the required processing load and aggregates peers' resources for common use. The model is based on the principles of local computation at each peer, direct inter-peer communication, and a shared storage space.

Improving The Boosted Correlogram, Nicholas Howe, Amanda Ricketson

Computer Science: Faculty Publications

Introduced seven years ago, the correlogram is a simple statistical image descriptor that nevertheless performs strongly on image retrieval tasks. As a result it has found wide use as a component inside larger systems for content-based image and video retrieval. Yet few studies have examined potential variants of the correlogram or compared their performance to the original. This paper presents systematic experiments on the correlogram and several variants under different conditions, showing that the results may vary significantly depending on both the variant chosen and its mode of application. As expected, the experimental setup combining correlogram variants with boosting shows …

Modeling Usage Of An Online Research Community, Yi Zhang

Dissertations

Although online communities have been thought of as a new way for collaboration across geographic boundaries in the scientific world, they have a problem attracting people to keep visiting. The main purpose of this study is to understand how people behave in such communities, and to build and evaluate tools to stimulate engagement in a research community. These tools were designed based on a research framework of factors that influence online participation and relationship development.

There are two main objectives for people to join an online community, information sharing and interpersonal relationship development, such as friends or colleagues. The tools …

Slimsvm : A Simple Implementation Of Support Vector Machine For Analysis Of Microarray Data, Avik Karmaker

Theses

Support Vector Machine (SVM) is a supervised machine learning technique being widely used in multiple areas of biological analysis including microarray data analysis. SlimSVM has been developed with the intention of replacing OSU SVM as the classification component of GenoIterSVM in order to make it independent of other SVM packages. GenolterSVM, developed by Dr. Marc Ma, is a SVM implementation with an iterative refinement algorithm for improved accuracy of classification of genotype microarray data. SlimSVM is an object-oriented, modular, and easy-to-use implementation written in C++. It supports dot (linear) and polynomial (non-linear) kernels. The program has been tested with artificial …

An Ecological Display For Robot Teleoperation, Robert W. Ricks

Theses and Dissertations

This thesis presents an interface for effectively teleoperating robots that combines an ecological display of range and video information with quickening based on dead-reckoning prediction. This display is built by viewing range and video information from a virtual camera trailing the robot. This is rendered in 3-D by using standard hardware acceleration and 3-D graphics software. Our studies demonstrate that this interface improves performance for most people, including those that do not have much previous experience with robotics. These studies involved 32 test subjects in a simulated environment and 8 in the real world. Subjects were required to drive the …

Singular Value Decomposition Of Analogs Of Gbr 12909, Anna Fiorentino

Theses

Analogs of GBR 12909 are drugs that could potentially be used to treat cocaine addiction. Singular Value Decomposition (SVD) is a multivariate analysis technique used to show relationships between the data and the variables associated with the data. The input data consists of the conformers of each analog (DM324, 728 conformers; TP250, 739 conformers) along with the eight torsional angles (Al, A2, B1-B6). A novel scaling technique was developed to address the problem of data circularity by subtracting the values of the torsional angles of the global energy minimum conformation from those of each conformer.

In SVD the original data …

Sb9: The Ninth Catalogue Of Spectroscopic Binary Orbits, Dimitri Pourbaix, Andrei A. Tokovinin, Alan H. Batten, Francis C. Fekel, William I. Hartkopf, Hugo Levato, Nidia I. Morrell, Guillermo Torres, Stephane Udry

Information Systems and Engineering Management Research Publications

The Ninth Catalogue of Spectroscopic Binary Orbits (http://sb9.astro.ulb.ac.be) continues the series of compilations of spectroscopic orbits carried out over the past 35 years by Batten and collaborators. As of 2004 May 1st, the new Catalogue holds orbits for 2386 systems. Some essential differences between this catalogue and its predecessors are outlined and three straightforward applications are presented: (1) completeness assessment: period distribution of SB1s and SB2s; (2) shortest periods across the H-R diagram; (3) period-eccentricity relation.

A Qualitative Method For Dynamic Transport Selection In Heterogeneous Wireless Environments, Heidi R. Duffin

Theses and Dissertations

Computing devices are commonly equipped with multiple transport technologies such as IrDA, Bluetooth and WiFi. Transport switching technologies, such as Quality of Transport (QoT), take advantage of this heterogeneity to keep network sessions active as users move in and out of range of various transports or as the networking environment changes. During an active session, the goal is to keep the device connected over the best transport currently available. To accomplish that, this thesis introduces a two-phase decision making protocol. In phase one, intra-device prioritization, users indicate the relative importance of criteria such as speed, power, service charge, or signal …

Direct Least-Squares Ellipse Fitting, Jane Courtney, Annraoi Depaor

Conference Papers

Many biological and astronomical forms can be best represented by ellipses. While some more complex curves might represent the shape more accurately, ellipses have the advantage that they are easily parameterised and define the location, orientation and dimensions of the data more clearly. In this paper, we present a method of direct least-squares ellipse fitting by solving a generalised eigensystem. This is more efficient and more accurate than many alternative approaches to the ellipse-fitting problem such as fuzzy c-shells clustering and Hough transforms. This method was developed for human body modelling as part of a larger project to design a …

Scheduling Algorithms For Cioq Switches, Prashanth Pappu, Jonathan S. Turner

All Computer Science and Engineering Research

Most scalable switches are required to buffer packets at both their inputs and outputs to overcome the slow memory speeds of packet queues. This thesis deals with the design of scheduling algorithms for such Combined Input and Output Queued (CIOQ) switches. For crossbar based CIOQ switches, we demonstrate the underperformance of commercially used scheduling algorithms under overload traffic conditions using targeted stress tests and present ideas to develop robust, stress resistant versions of these algorithms that are still simple enough to be implemented in high speed switches. To regulate the flow of traffic in buffered, multi-stage switches, we introduce a …

The Tirac™ Development Toolkit: Purpose And Overview, Jens G. Pohl, Kym Jason Pohl, Russell Leighton, Michael Zang, Steven Gollery, Mark Porczak

Collaborative Agent Design (CAD) Research Center

This report provides an overview description of the Toolkit for Information Representation and Agent Collaboration (TIRAC™) software framework for the development of intelligent decision-support applications. More technical descriptions of TIRAC™ are contained in a companion CDM Technical Report (CDM-19-03) entitled: ‘The TIRAC™ Development Toolkit: Technical Description’.

TIRAC™ is an application development framework and toolkit for decision-support systems incorporating software agents that collaborate with each other and human users to monitor changes (i.e., events) in the state of problem situations, generate and evaluate alternative plans, and alert human users to immediate and developing resource shortages, failures, threats, and similar adverse conditions. …

T-Spline Simplification And Local Refinement, David L. Cardon, G. Thomas Finnigan, Nicholas S. North, Thomas W. Sederberg, Jianmin Zheng, Tom Lyche

Faculty Publications

A typical NURBS surface model has a large percentage of superfluous control points that significantly interfere with the design process. This paper presents an algorithm for eliminating such superfluous control points, producing a T-spline. The algorithm can remove substantially more control points than competing methods such as B-spline wavelet decomposition. The paper also presents a new T-spline local refinement algorithm and answers two fundamental open questions on T-spline theory.