Digital Commons Network^™

Learning Mixture Models With The Regularized Latent Maximum Entropy Principle, Shaojun Wang, Dale Schuurmans, Fuchun Peng, Yunxin Zhao

Kno.e.sis Publications

This paper presents a new approach to estimating mixture models based on a recent inference principle we have proposed: the latent maximum entropy principle (LME). LME is different from Jaynes' maximum entropy principle, standard maximum likelihood, and maximum a posteriori probability estimation. We demonstrate the LME principle by deriving new algorithms for mixture model estimation, and show how robust new variants of the expectation maximization (EM) algorithm can be developed. We show that a regularized version of LME (RLME), is effective at estimating mixture models. It generally yields better results than plain LME, which in turn is often better than …

Task-Focused Summarization Of Email, Eric K. Ringger, Richard Campbell, Simon Corston-Oliver, Michael Gamon

Faculty Publications

We describe SmartMail, a prototype system for automatically identifying action items (tasks) in email messages. SmartMail presents the user with a task-focused summary of a message. The summary consists of a list of action items extracted from the message. The user can add these action items to their “to do” list.

Probing The Posthuman: Richard Powers' Galatea 2.2 And The Mind-Body Problem, Miranda Campbell

Reconstruction: Studies in Contemporary Culture

[Editors' Introduction]

In this paper, Miranda Campbell discusses Richard Powers' novel Galatea 2.2 and argues that this work is situated at the intersection of the posthumanist and humanist discourses. Campbell examines Powers' approach to the mind-body problem, his interrogation of the limits and limitations of posthumanism, and its dissolution of the importance of the body, difference, and agency. In the posthuman setting of the Center for Advanced Science of this novel, scientists integrate the mind into the body through its designation as a mechanically functioning brain. At the Center, the binary of human and machine begins to erode with the …

Plone And Content Management, George K. Thiruvathukal, Konstantin Läufer

Computer Science: Faculty Publications and Other Works

In this column, the authors look at Plone, which they feel is one of the best content management systems available today. Even better, it?s distributed under a free open-source license: the cost of getting started is only limited to the time you have available to set up the software on a server. Plone is written in Python and uses the Zope application server infrastructure; it runs on most modern operating systems. The authors have even set it up at Loyola University Chicago in the Department of Computer Science. Besides being two faculty members who rely on Plone to host all …

Incremental Evaluation Of Sliding- Window Queries Over Data Streams, T. M. Ghanem, M. Hammad, M. Mokbel, Walid G. Aref, Ahmed K. Elmagarmid

Department of Computer Science Technical Reports

No abstract provided.

Janus: Towards Robust And Malicious Resilient Routing In Hybrid Wireless Networks, Bogdan Carbunar, Ioanis Ioannidis, Cristina Nita-Rotaru

Department of Computer Science Technical Reports

No abstract provided.

Quality-Aware Replication Of Multimedia Data, Yi-Cheng Tu, Sunil Prabhakar

Department of Computer Science Technical Reports

No abstract provided.

Fuzzy Modeling Of Electromagnetic Emissions From Portable Electronic Devices Onboard Commercial Aircraft, Madiha Jamil Jafri

Electrical & Computer Engineering Theses & Dissertations

The use of Portable Electronic Devices (PEDs) is prohibited during take-off and landing of an aircraft because PEDs may emit signals that can interfere with the aircraft's navigation and communication systems. The electromagnetic interference (EMI) on the aircraft's electronics due to PEDs emissions is examined for Boeing 737 and 747 aircraft. This work, funded by the NASA Graduate Researchers Program, uses Interference Path Loss (IPL) data, collected by researchers from NASA Langley Research Center, Eagles Wings Inc. and United Airlines on several out-of-service United B737 and B747 airplanes.

B737 and B747 IPL data has been analyzed using a graphical analysis …

Improving Tcp Performance By Estimating Errors In A Long Delay, High Error Rate Environment, Stephanie E. Carroll

Theses and Dissertations

Interest in finding methods of improving TCP performance over satellite and wireless networks is high. This has been an active area of research within the networking community. This research develops an algorithm, CETEN-R for TCP to determine if a particular packet is lost due to congestion or corruption and react accordingly. An analysis of the performance of CETEN-R under a variety of conditions is studied and then compared to TCP Reno and TCP New Reno. When delay is high and the error rate is high CETEN-R showed a 77.5% increase in goodput over TCP New Reno and a 33.8% increase …

Learning Multiple Correct Classifications From Incomplete Data Using Weakened Implicit Negatives, Dan A. Ventura, Stephen Whiting

Faculty Publications

Classification problems with output class overlap create problems for standard neural network approaches. We present a modification of a simple feed-forward neural network that is capable of learning problems with output overlap, including problems exhibiting hierarchical class structures in the output. Our method of applying weakened implicit negatives to address overlap and ambiguity allows the algorithm to learn a large portion of the hierarchical structure from very incomplete data. Our results show an improvement of approximately 58% over a standard backpropagation network on the hierarchical problem.

Qos Provisioning For Multi-Class Traffic In Wireless Networks, Mona El-Kadi Rizvi

Computer Science Theses & Dissertations

Physical constraints, bandwidth constraints and host mobility all contribute to the difficulty of providing Quality of Service (QoS) guarantees in wireless networks. There is a growing demand for wireless networks to support all the services that are available on wired networks. These diverse services, such as email, instant messaging, web browsing, video conferencing, telephony and paging all place different demands on the network, making QoS provisioning for wireless networks that carry multiple classes of traffic a complex problem. We have developed a set of admission control and resource reservation schemes for QoS provisioning in multi-class wireless networks.

We present three …

An Interactive Learning Environment For A Dynamic Educational Digital Library, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng, Eng-Kai Suen

Research Collection School Of Computing and Information Systems

GeogDL is a digital library of geography examination resources designed to assist students in preparing for a national geography examination in Singapore. We describe an interactive learning environment built into GeogDL that consists of four major components. The practice and review module allows students to attempt individual examination questions, the mock exam provides a simulation of the actual geography examination, the trends analysis tool provides an overview of the types of questions asked in previous examinations, while the contributions module allows students and teachers to create and share knowledge within the digital library.

Teabag: A Debugger For Curry, Stephen Lee Johnson

Dissertations and Theses

This thesis describes TeaBag, which is a debugger for functional logic computations. TeaBag is an accessory of a virtual machine currently under development. A distinctive feature of this machine is its operational completeness of computations, which places novel demands on a debugger. This thesis describes the features of TeaBag, in particular the handling of non-determinism, the ability to control nondeterministic steps, to remove context information, to toggle eager evaluation, and to set breakpoints on both functions and terms. This thesis also describes TeaBag's architecture and its interaction with the associated virtual machine. Finally, some debugging sessions of defective programs are …

An Empirical Investigation On End-Users’ Acceptance Of Enterprise Systems, Fiona Fui-Hoon Nah, Xin Tan, Soon Hing Teh

Research Collection School Of Computing and Information Systems

Despite the huge investments by organizations in ERP implementation, maintenance, and user training, ERP implementation failures and less-than-satisfactory productivity improvements are common. End-users’ reluctance or unwillingness to adopt or use the newly implemented ERP system is often cited as one of the main reasons for ERP failures. To examine factors leading to the lack of end-user acceptance of ERP systems, we reviewed the literature on user adoption of IT in mandatory contexts, developed hypotheses to explain ERP user acceptance, and conducted a survey study to test the hypotheses. In particular, we examined end-users’ attitudes toward system use and symbolic adoption, …

Infosemm: Infosys It Security Maturity Model: A Report, Arcot Desai Narasimhalu, N. Dayasindhu, Raghavan Subramanian

Research Collection School Of Computing and Information Systems

Businesses are faced with a continuing battle related to cyber security related issues ranging from cyber attacks all the way to cyber (information) war. These issues affect result in information, system, reputation, and revenue related risks. These risks arise because of vulnerabilities introduced in three major parts of the enterprise – infrastructure, intelligence and practices. This report provides a rating system for representing the security health of enterprises.

Biased Support Vector Machine For Relevance Feedback In Image Retrieval, Steven Hoi, Chi-Hang Chan, Kaizhu Huang, Michael R. Lyu, Irwin King

Research Collection School Of Computing and Information Systems

Recently, support vector machines (SVMs) have been engaged on relevance feedback tasks in content-based image retrieval. Typical approaches by SVMs treat the relevance feedback as a strict binary classification problem. However, these approaches do not consider an important issue of relevance feedback, i.e. the unbalanced dataset problem, in which the negative instances largely outnumber the positive instances. For solving this problem, we propose a novel technique to formulate the relevance feedback based on a modified SVM called biased support vector machine (Biased SVM or BSVM). Mathematical formulation and explanations are provided for showing the advantages. Experiments are conducted to evaluate …

Knowledge Management Using Semantic Web Languages And Technologies, Steven J. Gollery, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Each organization of more than a few persons generates a number of documents containing information about the activities of the organization. The sum of these documents provides a kind of organizational memory that can be used both in evaluations of past performance and as the basis of future planning based on previous experience.

Unfortunately, the nature of these documents mitigates against the reuse of information for purposes other than those for which each document was originally intended. To locate all the information about some aspect of the organization, it frequently becomes necessary for human beings to search a mass of …

Type-Safe Operating System Abstractions, Lea Wittie

Dartmouth College Ph.D Dissertations

Operating systems and low-level applications are usually written in languages like C and assembly, which provide access to low-level abstractions. These languages have unsafe type systems that allow many bugs to slip by programmers. For example, in 1988, the Internet Worm exploited several insecure points in Unix including the finger command. A call to finger with an unexpected argument caused a buffer overflow, leading to the shutdown of most Internet traffic. A finger application written in a type-safe language would have prevented its exploit and limited the points the Internet Worm could attack. Such vulnerabilities are unacceptable in security-critical applications …

Load Balancing Parallel Explicit State Model Checking, Rahul Kumar

Theses and Dissertations

This research first identifies some of the key concerns about the techniques and algorithms developed for distributed and parallel model checking; specifically, the inherent problem with load balancing and large queue sizes resultant in a static partition algorithm. This research then presents a load balancing algorithm to improve the run time performance in distributed model checking, reduce maximum queue size, and reduce the number of states expanded before error discovery. The load balancing algorithm is based on Generalized Dimension Exchange (GDE). This research presents an empirical analysis of the GDE based load balancing algorithm on three different supercomputing architectures---distributed memory …

Outdoor Experimental Comparison Of Four Ad Hoc Routing Algorithms, Robert S. Gray, David Kotz, Calvin Newport, Nikita Dubrovsky, Aaron Fiske, Jason Liu, Christopher Masone, Susan Mcgrath, Yougu Yuan

Computer Science Technical Reports

Most comparisons of wireless ad hoc routing algorithms involve simulated or indoor trial runs, or outdoor runs with only a small number of nodes, potentially leading to an incorrect picture of algorithm performance. In this paper, we report on the results of an outdoor trial run of four different routing algorithms, APRL, AODV, GPSR, and STARA, running on top of thirty-three 802.11-enabled laptops moving randomly through an athletic field. The laptops generated random traffic according to the traffic patterns observed in a prototype application, and ran each routing algorithm for a fifteen-minute period over the course of the hour-long trial …

Simulating Mobile Ad Hoc Networks: A Quantitative Evaluation Of Common Manet Simulation Models, Calvin Newport

Dartmouth College Undergraduate Theses

Because it is difficult and costly to conduct real-world mobile ad hoc network experiments, researchers commonly rely on computer simulation to evaluate their routing protocols. However, simulation is far from perfect. A growing number of studies indicate that simulated results can be dramatically affected by several sensitive simulation parameters. It is also commonly noted that most simulation models make simplifying assumptions about radio behavior. This situation casts doubt on the reliability and applicability of many ad hoc network simulation results. In this study, we begin with a large outdoor routing experiment testing the performance of four popular ad hoc algorithms …

Ppl: A Packet Processing Language, Eric G. Krupski

Dartmouth College Undergraduate Theses

Any computing device or system that uses the internet needs to analyze and identify the contents of network packets. Code that does this is often written in C, but reading, identifying, and manipulating network packets in C requires writing tricky and tedious code. Previous work has offered specification languages for describing the format of network packets, which would allow packet type identification without the hassles of doing this task in C. For example, McCann and Chandra's Packet Types [3] system allows the programmer to define arbitrary packet types and generates C unctions which match given data against a specified packet …

Solving Large Mdps Quickly With Partitioned Value Iteration, David Wingate

Theses and Dissertations

Value iteration is not typically considered a viable algorithm for solving large-scale MDPs because it converges too slowly. However, its performance can be dramatically improved by eliminating redundant or useless backups, and by backing up states in the right order. We present several methods designed to help structure value dependency, and present a systematic study of companion prioritization techniques which focus computation in useful regions of the state space. In order to scale to solve ever larger problems, we evaluate all enhancements and methods in the context of parallelizability. Using the enhancements, we discover that in many instances the limiting …

Efficient Wait-Free Implementation Of Atomic Multi-Word Buffer, Rachel B. Ringel

Dartmouth College Undergraduate Theses

This thesis proposes algorithms for implementing a atomic multi-word buffer, which can be accessed concurrently by multiple readers and a single writer, from the hardware-supported shared memory. The algorithms are required to be wait-free: each process reads or writes the multi-word buffer in a bounded number of its own steps, regardless of whether other processes are fast, slow or have crashed. Our first algorithm is built from multi-writer, multi-reader variables whereas the second algorithm is built from single-writer, multi-reader variables. For either algorithm, the worst-case running time of a read or a write operation on the m-word buffer is O(m). …

Testing The Greenpass Wireless Security System, Kimberly S. Powell

Dartmouth College Undergraduate Theses

Greenpass, developed by Nick Goffee, Sung Hoon Kim, Meiyuan Zhao and John Marchesini under the supervision of Sean Smith and Punch Taylor, is a wireless security solution that implements SPKI/SDSI delegation on top of X.509 keypairs within the EAP-TLS authentication protocol. This system aims to model the decentralized way that authorization flows in real-world enterprise settings and provide a seamless solution that allows for easy access to all resources in the network by both registered users and authorized guests. These goals are achieved through the deployment of a delegation tool, which allows an active entity associated to the organization's network …

A Secure Network Node Approach To The Policy Decision Point In Distributed Access Control, Geoffrey H. Stowe

Dartmouth College Undergraduate Theses

To date, the vast majority of access control research and development has been on gathering, managing, and exchanging information about users. But an equally important component which has yet to be fully developed is the Policy Decision Point - the system that decides whether an access request should be granted given certain attributes of the requestor. This paper describes the research and implementation of a new PDP system for an undergraduate honors project. This PDP system employs three unique features which differentiate it from existing technology: collaboration capabilities, trusted management, and interoperability with other access control systems. Security considerations and …

Content-Based Framework For Component Libraries, Franz J. Kurfess, Ching Kang Cheng, Z. Y. Wang, L. Jololian

Computer Science and Software Engineering

The construction of large software systems from existing components requires efficient access to possibly large collections of such components. In this paper, we present a content-based framework to organize this large collection of components in a semi-automatic fashion, according to an extensible user-defined ontology. Neural associative memories are used for fast, similarity-based access. Relevant characteristics of components are extracted and stored as a ``signature'' in such an associative memory, and during retrieval the closest matches to the query are indicated in very short time. In addition to content-based characteristics such as keywords, function and variable names, comments, and the location …

Algorithmic Fusion Of Gene Expression Profiling For Diffuse Large B-Cell Lymphoma Outcome Prediction, Qiuming Zhu, Hongmei Cui, Kahai Cao, Wing C. Chan

Computer Science Faculty Publications

Many different methods and techniques have been investigated for the processing and analysis of microarray gene expression profiling datasets. It is noted that the accuracy and reliability of the results are often dependent on the measurement approaches applied, and no single measurement so far is guaranteed to generate a satisfactory result. In this paper, an algorithmic fusion approach is presented for extracting genes that are predictive to clinical outcomes (survival-fatal) of diffuse large B-cell lymphoma on a set of microarray data for gene expression profiling. The approach integrates a set of measurements from different aspects in terms of the discrepancy …

Experimental Evaluation Of Wireless Simulation Assumptions, David Kotz, Calvin Newport, Robert S. Gray, Jason Liu, Yougu Yuan, Chip Elliott

Computer Science Technical Reports

All analytical and simulation research on ad~hoc wireless networks must necessarily model radio propagation using simplifying assumptions. Although it is tempting to assume that all radios have circular range, have perfect coverage in that range, and travel on a two-dimensional plane, most researchers are increasingly aware of the need to represent more realistic features, including hills, obstacles, link asymmetries, and unpredictable fading. Although many have noted the complexity of real radio propagation, and some have quantified the effect of overly simple assumptions on the simulation of ad~hoc network protocols, we provide a comprehensive review of six assumptions that are still …

Robust Security Mechnisms For Data Streams Systems, Mohamed Ali, Mohamed Eltabakh, Cristina Nita-Rotaru

Department of Computer Science Technical Reports

No abstract provided.