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Sketchwizard: Wizard Of Oz Prototyping Of Pen-Based User Interfaces, Richard C. Davis, T. Scott Saponas, Michael Shilman, James A. Landay Oct 2007

Sketchwizard: Wizard Of Oz Prototyping Of Pen-Based User Interfaces, Richard C. Davis, T. Scott Saponas, Michael Shilman, James A. Landay

Research Collection School Of Computing and Information Systems

SketchWizard allows designers to create Wizard of Oz prototypes of pen-based user interfaces in the early stages of design. In the past, designers have been inhibited from participating in the design of pen-based interfaces because of the inadequacy of paper prototypes and the difficulty of developing functional prototypes. In SketchWizard, designers and end users share a drawing canvas between two computers, allowing the designer to simulate the behavior of recognition or other technologies. Special editing features are provided to help designers respond quickly to end-user input. This paper describes the SketchWizard system and presents two evaluations of our approach. The …

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Preserving Privacy In Supply Chain Management: A Challenge For Next Generation Data Mining, Madhu Ahluwalia, Zhiyuan Chen, Arrya Gangopadhyay, Zhiling Guo Oct 2007

Preserving Privacy In Supply Chain Management: A Challenge For Next Generation Data Mining, Madhu Ahluwalia, Zhiyuan Chen, Arrya Gangopadhyay, Zhiling Guo

Research Collection School Of Computing and Information Systems

In this paper we identify a major area of research as a topic for next generation data mining. The research effort in the last decade on privacy preserving data mining has resulted in the development of numerous algorithms. However, most of the existing research has not been applied in any particular application context. Hence it is unclear whether the current algorithms are directly applicable in any particular problem context. In this paper we identify a significant application context that not only requires protection of privacy but also sophisticated data analysis. The area in question is supply chain management, arguably one …

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Comparisons Of An Adaptive Neural Network Based Controller And An Optimized Conventional Power System Stabilizer, Wenxin Liu, Ganesh K. Venayagamoorthy, Jagannathan Sarangapani, Donald C. Wunsch, Mariesa Crow, Li Liu, David A. Cartes Oct 2007

Comparisons Of An Adaptive Neural Network Based Controller And An Optimized Conventional Power System Stabilizer, Wenxin Liu, Ganesh K. Venayagamoorthy, Jagannathan Sarangapani, Donald C. Wunsch, Mariesa Crow, Li Liu, David A. Cartes

Electrical and Computer Engineering Faculty Research & Creative Works

Power system stabilizers are widely used to damp out the low frequency oscillations in power systems. In power system control literature, there is a lack of stability analysis for proposed controller designs. This paper proposes a Neural Network (NN) based stabilizing controller design based on a sixth order single machine infinite bus power system model. The NN is used to compensate the complex nonlinear dynamics of power system. To speed up the learning process, an adaptive signal is introduced to the NN's weights updating rule. The NN can be directly used online without offline training process. Magnitude constraint of the …

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Performance Of Network-Coding In Multi-Rate Wireless Environments For Multicast Applications, Luiz F. M. Viera, Archan Misra, Mario Gerla Oct 2007

Performance Of Network-Coding In Multi-Rate Wireless Environments For Multicast Applications, Luiz F. M. Viera, Archan Misra, Mario Gerla

Research Collection School Of Computing and Information Systems

This paper investigates the interaction between net-work coding and link-layer transmission rate diversity in multi-hop wireless networks. By appropriately mixing data packets at intermediate nodes, network coding allows a single multicast flow to achieve higher throughput to a set of receivers. Broadcast applications can also exploit link-layer rate diversity, whereby individual nodes can transmit at faster rates at the expense of corresponding smaller coverage area. We first demonstrate how combining rate-diversity with network coding can provide a larger capacity for data dissemination of a single multicast flow, and how consideration of rate diversity is critical for maximizing system throughput. We …

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Om-Based Video Shot Retrieval By One-To-One Matching, Yuxin Peng, Chong-Wah Ngo, Jianguo Xiao Oct 2007

Om-Based Video Shot Retrieval By One-To-One Matching, Yuxin Peng, Chong-Wah Ngo, Jianguo Xiao

Research Collection School Of Computing and Information Systems

This paper proposes a new approach for shot-based retrieval by optimal matching (OM), which provides an effective mechanism for the similarity measure and ranking of shots by one-to-one matching. In the proposed approach, a weighted bipartite graph is constructed to model the color similarity between two shots. Then OM based on Kuhn-Munkres algorithm is employed to compute the maximum weight of a constructed bipartite graph as the shot similarity value by one-to-one matching among frames. To improve the speed efficiency of OM, two improved algorithms are also proposed: bipartite graph construction based on subshots and bipartite graph construction based on …

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Gapprox: Mining Frequent Approximate Patterns From A Massive Network, Chen Chen, Xifeng Yan, Feida Zhu, Jiawei Han Oct 2007

Gapprox: Mining Frequent Approximate Patterns From A Massive Network, Chen Chen, Xifeng Yan, Feida Zhu, Jiawei Han

Research Collection School Of Computing and Information Systems

Recently, there arise a large number of graphs with massive sizes and complex structures in many new applications, such as biological networks, social networks, and the Web, demanding powerful data mining methods. Due to inherent noise or data diversity, it is crucial to address the issue of approximation, if one wants to mine patterns that are potentially interesting with tolerable variations. In this paper, we investigate the problem of mining frequent approximate patterns from a massive network and propose a method called gApprox. gApprox not only finds approximate network patterns, which is the key for many knowledge discovery applications on …

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Efficient Discovery Of Frequent Approximate Sequential Patterns, Feida Zhu, Xifeng Yan, Jiawei Han, Philip S. Yu Oct 2007

Efficient Discovery Of Frequent Approximate Sequential Patterns, Feida Zhu, Xifeng Yan, Jiawei Han, Philip S. Yu

Research Collection School Of Computing and Information Systems

We propose an efficient algorithm for mining frequent approximate sequential patterns under the Hamming distance model. Our algorithm gains its efficiency by adopting a "break-down-and-build-up" methodology. The "breakdown" is based on the observation that all occurrences of a frequent pattern can be classified into groups, which we call strands. We developed efficient algorithms to quickly mine out all strands by iterative growth. In the "build-up" stage, these strands are grouped up to form the support sets from which all approximate patterns would be identified. A salient feature of our algorithm is its ability to grow the frequent patterns by iteratively …

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Mining Modal Scenarios From Execution Traces, David Lo, Shahar Maoz, Siau-Cheng Khoo Oct 2007

Mining Modal Scenarios From Execution Traces, 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 method, a framework, and a tool, for mining inter-object scenario-based specifications in the form of a UML2-compliant variant of Damm and Harel's Live Sequence Charts (LSC), which 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. Moreover, we use previous research work and tools developed for LSC to visualize, analyze, manipulate, test, and thus evaluate the scenario-based specifications we mine. Our …

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Flexible Access Control To Jpeg 2000 Image Code-Streams, Yongdong Wu, Di Ma, Robert H. Deng Oct 2007

Flexible Access Control To Jpeg 2000 Image Code-Streams, Yongdong Wu, Di Ma, Robert H. Deng

Research Collection School Of Computing and Information Systems

JPEG 2000 is an international standard for still image compression in the 21st century. Part 8 of the standard, named JPSEC, is concerned with all the security aspects, in particular to access control and authentication. This paper presents a novel access control scheme for JPEG 2000 image code-streams. The proposed scheme is secure against collusion attacks and highly efficient. The scheme is also very flexible, allowing access control to JPEG 2000 image code-streams according to any combination of resolution, quality layer and region of interest. The "encrypt once, decrypt many ways" property of our scheme is designed to work seamlessly …

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A Multitude Of Opinions: Mining Online Rating Data, Hady Wirawan Lauw, Ee Peng Lim Oct 2007

A Multitude Of Opinions: Mining Online Rating Data, Hady Wirawan Lauw, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Online rating system is a popular feature of Web 2.0 applications. It typically involves a set of reviewers assigning rating scores (based on various evaluation criteria) to a set of objects. We identify two objectives for research on online rating data, namely achieving effective evaluation of objects and learning behaviors of reviewers/objects. These two objectives have conventionally been pursued separately. We argue that the future research direction should focus on the integration of these two objectives, as well as the integration between rating data and other types of data.

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Npake+: A Hierarchical Group Password-Authenticated Key Exchange Protocol Using Different Passwords, Zhiguo Wan, Robert H. Deng, Feng Bao, Bart Preneel Oct 2007

Npake+: A Hierarchical Group Password-Authenticated Key Exchange Protocol Using Different Passwords, Zhiguo Wan, Robert H. Deng, Feng Bao, Bart Preneel

Research Collection School Of Computing and Information Systems

Although two-party password-authenticated key exchange (PAKE) protocols have been intensively studied in recent years, group PAKE protocols have received little attention. In this paper, we propose a hierarchical group PAKE protocol nPAKE+ protocol under the setting where each party shares an independent password with a trusted server. The nPAKE+ protocol is a novel combination of the hierarchical key tree structure and the password-based Diffie-Hellman exchange, and hence it achieves substantial gain in computation efficiency. In particular, the computation cost for each client in our protocol is only O(logn). Additionally, the hierarchical feature of nPAKE+ enables every subgroup obtains their own …

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Analyzing Service Usage Patterns: Methodology And Simulation, Qianhui (Althea) Liang, Jen-Yao Chung Oct 2007

Analyzing Service Usage Patterns: Methodology And Simulation, Qianhui (Althea) Liang, Jen-Yao Chung

Research Collection School Of Computing and Information Systems

This paper proposes that service mining technology will power the construction of new business services via both intra- and inter-enterprise service assembly within the Service Oriented Architecture (SOA) framework. We investigate the methodologies of service mining at the component level of service usage. We also demonstrate how mining of service usage patterns is intended to be used to improve different aspects of service composition. Simulation experiments conducted for mining at the component level are analyzed. The processing details within a general service mining deployment are demonstrated.

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Follow The Leader? Price Change Timing In Internet-Based Selling, R. J. Kauffman, Charles A. Wood Oct 2007

Follow The Leader? Price Change Timing In Internet-Based Selling, R. J. Kauffman, Charles A. Wood

Research Collection School Of Computing and Information Systems

Internet technologies should lessen information asymmetry, prompting competitive price reactions, but this does not seem to be happening in Internet-based selling. We study empirical regularities of price change timing for music CD vendors and booksellers to assess several theoretical explanations. Our sample includes 123, 680 daily prices for 169 products and 53 firms. Bertrand competition is insufficient to explain our observation that sellers do not shift prices this way. Tacitly collusive responses to competitors' price changes are observed rather than price changes solely in response to demand or cost shifts as would be expected with Bertrand competition. We find evidence …

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Option-Based Risk Management: A Field Study Of Sequential Information Technology Investment Decisions, Michel Benaroch, Mark Jeffery, Robert John Kauffman, Sandeep Shah Oct 2007

Option-Based Risk Management: A Field Study Of Sequential Information Technology Investment Decisions, Michel Benaroch, Mark Jeffery, Robert John Kauffman, Sandeep Shah

Research Collection School Of Computing and Information Systems

This field study research evaluates the viability of applying an option-based risk management (OBRiM) framework, and its accompanying theoretical perspective and methodology, to real-world sequential information technology (IT) investment problems. These problems involve alternative investment structures that bear different risk profiles for the firm, and also may improve the payoffs of the associated projects and the organization's performance. We sought to surface the costs, benefits, and risks associated with a complex sequential investment setting that has the key features that OBRiM treats. We combine traditional, purchased real options that subsequently create strategic flexibility for the decision maker, with implicit or …

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Blacklistable Anonymous Credentials: Blocking Misbehaving Users Without Ttps (Extended Version), Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith Sep 2007

Blacklistable Anonymous Credentials: Blocking Misbehaving Users Without Ttps (Extended Version), Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith

Computer Science Technical Reports

Several credential systems have been proposed in which users can authenticate to services anonymously. Since anonymity can give users the license to misbehave, some variants allow the selective deanonymization (or linking) of misbehaving users upon a complaint to a trusted third party (TTP). The ability of the TTP to revoke a user's privacy at any time, however, is too strong a punishment for misbehavior. To limit the scope of deanonymization, systems such as ``e-cash'' have been proposed in which users are deanonymized under only certain types of well-defined misbehavior such as ``double spending.'' While useful in some applications, it is …

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Limitations And Extensions Of The Wolf-Phc Algorithm, Philip R. Cook Sep 2007

Limitations And Extensions Of The Wolf-Phc Algorithm, Philip R. Cook

Theses and Dissertations

Policy Hill Climbing (PHC) is a reinforcement learning algorithm that extends Q-learning to learn probabilistic policies for multi-agent games. WoLF-PHC extends PHC with the "win or learn fast" principle. A proof that PHC will diverge in self-play when playing Shapley's game is given, and WoLF-PHC is shown empirically to diverge as well. Various WoLF-PHC based modifications were created, evaluated, and compared in an attempt to obtain convergence to the single shot Nash equilibrium when playing Shapley's game in self-play without using more information than WoLF-PHC uses. Partial Commitment WoLF-PHC (PCWoLF-PHC), which performs best on Shapley's game, is tested on other …

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Using A Mini-Uav To Support Wilderness Search And Rescue: Practices For Human-Robot Teaming, Julie A. Adams, Brian G. Buss, Joseph L. Cooper, Michael A. Goodrich, Curtis Humphrey, Ron Zeeman Sep 2007

Using A Mini-Uav To Support Wilderness Search And Rescue: Practices For Human-Robot Teaming, Julie A. Adams, Brian G. Buss, Joseph L. Cooper, Michael A. Goodrich, Curtis Humphrey, Ron Zeeman

Faculty Publications

Wilderness Search and Rescue can benefit from aerial imagery of the search area. Mini Unmanned Aerial Vehicles can potentially provide such imagery, provided that the autonomy, search algorithms, and operator control unit are designed to support coordinated human-robot search teams. Using results from formal analyses of the WiSAR problem domain, we summarize and discuss information flow requirements for WiSAR with an eye toward the efficient use of mUAVs to support search. We then identify and discuss three different operational paradigms for performing field searches, and identify influences that affect which human-robot team paradigm is best. Since the likely location of …

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A Utile Function Optimizer, James Carroll, Christopher K. Monson, Kevin Seppi Sep 2007

A Utile Function Optimizer, James Carroll, Christopher K. Monson, Kevin Seppi

Faculty Publications

We recast the problem of unconstrained continuous evolutionary optimization as inference in a fixed graphical model. This approach allows us to address several pervasive issues in optimization, including the traditionally difficult problem of selecting an algorithm that is most appropriate for a given task. This is accomplished by placing a prior distribution over the expected class of functions, then employing inference and intuitively defined utilities and costs to transform the evolutionary optimization problem into one of active sampling. This allows us to pose an approach to optimization that is optimal for each expressly stated function class. The resulting solution methodology …

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Parallel Pso Using Mapreduce, Andrew Mcnabb, Christopher K. Monson, Kevin Seppi Sep 2007

Parallel Pso Using Mapreduce, Andrew Mcnabb, Christopher K. Monson, Kevin Seppi

Faculty Publications

In optimization problems involving large amounts of data, such as web content, commercial transaction information, or bioinformatics data, individual function evaluations may take minutes or even hours. Particle Swarm Optimization (PSO) must be parallelized for such functions. However, large-scale parallel programs must communicate efficiently, balance work across all processors, and address problems such as failed nodes. We present MapReduce Particle Swarm Optimization (MRPSO), a PSO implementation based on the MapReduce parallel programming model. We describe MapReduce and show how PSO can be naturally expressed in this model, without explicitly addressing any of the details of parallelization. We present a benchmark …

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Blueprint For Iteratively Hardening Power Grids Employing Unified Power Flow Controllers, William M. Siever, Ann K. Miller, Daniel R. Tauritz Sep 2007

Blueprint For Iteratively Hardening Power Grids Employing Unified Power Flow Controllers, William M. Siever, Ann K. Miller, Daniel R. Tauritz

Electrical and Computer Engineering Faculty Research & Creative Works

A stable electricity supply is vital for modern society. However, many parts of our power transmission grid are operating near their operational limits. Such stressed systems are vulnerable to cascading failures, where a few small faults can induce a cascade of failures potentially leading to a major blackout The unified power flow controller (UPFC), the most powerful highspeed, semi-conductor based power flow device, can be used as a theoretical model to study how these devices can be used to improve power grid resilience. The blueprint presented here can be used to iteratively identify critical weaknesses in power grids and to …

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Interactive Web Portal Application For Ambalta School For Children With Autism, Cathy Talbot Sep 2007

Interactive Web Portal Application For Ambalta School For Children With Autism, Cathy Talbot

Regis University Student Publications (comprehensive collection)

Abalta is a school, based in Galway, designed to educate children who suffer from autism. The school was borne out of the identified need for children with autism to get a specific focused education. In July, 2001, four sets of parents came together, using their own personal funds, to establish the school and had it up and running by September, 2001. It took months of hard work, political negotiating, and lobbying, culminating with a high court case to attain funding from the state. In today's Internet-oriented world, a web application is essential for businesses, organiiations and individuals to optimiie their …

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Improving Neural Network Classification Training, Michael Edwin Rimer Sep 2007

Improving Neural Network Classification Training, Michael Edwin Rimer

Theses and Dissertations

The following work presents a new set of general methods for improving neural network accuracy on classification tasks, grouped under the label of classification-based methods. The central theme of these approaches is to provide problem representations and error functions that more directly improve classification accuracy than conventional learning and error functions. The CB1 algorithm attempts to maximize classification accuracy by selectively backpropagating error only on misclassified training patterns. CB2 incorporates a sliding error threshold to the CB1 algorithm, interpolating between the behavior of CB1 and standard error backpropagation as training progresses in order to avoid prematurely saturated network weights. CB3 …

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A Computational Model Of Culture-Specific Conversational Behavior, Dusan Jan, David Herrera, Bilyana Martinovski, David Novick, David Traum Sep 2007

A Computational Model Of Culture-Specific Conversational Behavior, Dusan Jan, David Herrera, Bilyana Martinovski, David Novick, David Traum

Selected Works Temporary Series

This paper presents a model for simulating cultural differences in the conversational behavior of virtual agents. The model provides parameters for differences in proxemics, gaze and overlap in turn taking.We present a review of literature on these factors and show results of a study where native speakers of Nrth American English, Mexican Spanish and Arabic were asked to rate the realism of the simulations generated based on different cultural parameters with respect to their culture.

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Hardness For Explicit State Software Model Checking Benchmarks, Eric G. Mercer, Neha Rungta Sep 2007

Hardness For Explicit State Software Model Checking Benchmarks, Eric G. Mercer, Neha Rungta

Faculty Publications

Directed model checking algorithms focus computation resources in the error-prone areas of concurrent systems. The algorithms depend on some empirical analysis to report their performance gains. Recent work characterizes the hardness of models used in the analysis as an estimated number of paths in the model that contain an error. This hardness metric is computed using a stateless random walk. We show that this is not a good hardness metric because models labeled hard with a stateless random walk metric have easily discoverable errors with a stateful randomized search. We present an analysis which shows that a hardness metric based …

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Poisson Disk Point Sets By Hierarchical Dart Throwing, David Cline, Parris K. Egbert, Kenric B. White Sep 2007

Poisson Disk Point Sets By Hierarchical Dart Throwing, David Cline, Parris K. Egbert, Kenric B. White

Faculty Publications

Poisson disk point sets are “ideally” generated through a process of dart throwing. The naive dart throwing algorithm is extremely expensive if a maximal set is desired, however. In this paper we present a hierarchical dart throwing procedure which produces point sets that are equivalent to naive dart throwing, but is very fast. The procedure works by intelligently excluding areas known to be fully covered by existing samples. By excluding covered regions, the probability of accepting a thrown dart is greatly increased. Our algorithm is conceptually simple, performs dart throwing in O(N) time and memory, and produces a maximal point …

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Image-Based Color Schemes, Bryan S. Morse, Daniel Thornton, Qing Xia, John Uibel Sep 2007

Image-Based Color Schemes, Bryan S. Morse, Daniel Thornton, Qing Xia, John Uibel

Faculty Publications

This paper presents a novel method for generating color schemes based on images intended to anchor color designs. This has wide applicability for web pages, printed materials, or other applications where images are used as a key part of the overall design. Unlike methods that are variants of color quantization and try to pixel-wise approximate the image, this method draws on graphic-design principles by emphasizing hue selection first, weighting effects of color by saturation, and considering the local spatial coherency in order to determine the overall visual impact of a color. Results demonstrate that the method generalizes to a wide …

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A Survey Of Schema Matching Research, Roger Blake Sep 2007

A Survey Of Schema Matching Research, Roger Blake

College of Management Working Papers and Reports

Schema matching is the process of developing semantic matches between two or more schemas. The purpose of schema matching is generally either to merge two or more databases, or to enable queries on multiple, heterogeneous databases to be formulated on a single schema (Doan and Halevy 2005). This paper develops a taxonomy of schema matching approaches, classifying them as being based on a combination schema matching technique and the type of data used by those techniques. Schema matching techniques are categorized as being based on rules, learning, or ontology, and the type of data used is categorized as being based …

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Evaluating Bag-Of-Visual-Words Representations In Scene Classification, Jun Yang, Yu-Gang Jiang, Alexander G. Hauptmann, Chong-Wah Ngo Sep 2007

Evaluating Bag-Of-Visual-Words Representations In Scene Classification, Jun Yang, Yu-Gang Jiang, Alexander G. Hauptmann, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Based on keypoints extracted as salient image patches, an image can be described as a “bag of visual words” and this representation has been used in scene classification. The choice of dimension, selection, and weighting of visual words in this representation is crucial to the classification performance but has not been thoroughly studied in previous work. Given the analogy between this representation and the bag-of-words representation of text documents, we apply techniques used in text categorization, including term weighting, stop word removal, feature selection, to generate image representations that differ in the dimension, selection, and weighting of visual words. The …

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Novelty Detection For Cross-Lingual News Stories With Visual Duplicates And Speech Transcripts, Xiao Wu, Alexander G. Hauptmann, Chong-Wah Ngo Sep 2007

Novelty Detection For Cross-Lingual News Stories With Visual Duplicates And Speech Transcripts, Xiao Wu, Alexander G. Hauptmann, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

An overwhelming volume of news videos from different channels and languages is available today, which demands automatic management of this abundant information. To effectively search, retrieve, browse and track cross-lingual news stories, a news story similarity measure plays a critical role in assessing the novelty and redundancy among them. In this paper, we explore the novelty and redundancy detection with visual duplicates and speech transcripts for cross-lingual news stories. News stories are represented by a sequence of keyframes in the visual track and a set of words extracted from speech transcript in the audio track. A major difference to pure …

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Difference Computation Of Large Models, Christoph Treude, Stefan Berlik, Sven Wenzel, Udo Kelter Sep 2007

Difference Computation Of Large Models, Christoph Treude, Stefan Berlik, Sven Wenzel, Udo Kelter

Research Collection School Of Computing and Information Systems

Modern software engineering practices lead to large models which exist in many versions. Version management systems should offer a service to compare, and possibly merge, these models. The computation of a difference between large models is a big challenge; current algorithms are too inefficient here. We present a new technique for computing differences between models. In practical tests, this technique has been an order of magnitude faster than currently known algorithms. The main idea is to use a high-dimensional search tree for efficiently finding similar model elements. Individual elements are mapped onto a vector of numerical values using a collection …

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