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Articles 4861 - 4890 of 7332

Full-Text Articles in Computer Sciences

Discontinuities And Best Practices In Virtual Research Collaboration, Vipin Arora, Deepak Khazanchi, Bjørn Erik Munkvold, Dawn Owens, Karen Stendal, Alvin Tarrell, Adeola Wale-Kolade, Sofi Westin, Ilze Zigurs May 2012

Discontinuities And Best Practices In Virtual Research Collaboration, Vipin Arora, Deepak Khazanchi, Bjørn Erik Munkvold, Dawn Owens, Karen Stendal, Alvin Tarrell, Adeola Wale-Kolade, Sofi Westin, Ilze Zigurs

Information Systems and Quantitative Analysis Faculty Proceedings & Presentations

Research collaboration has become increasingly global, as collaboration technologies continue to advance and as research problems become more interdisciplinary and global. Virtual research teams have processes and challenges that are unique from a typical virtual team, and we need a better understanding of how such teams can utilize virtual research environments to their advantage. We examine this question from a review of the relevant literature and an analysis of experiences and reflections from a doctoral seminar that studied and experienced the process of virtual research collaboration.


Insider Threat Mitigation Models Based On Thresholds And Dependencies, Harini Ragavan May 2012

Insider Threat Mitigation Models Based On Thresholds And Dependencies, Harini Ragavan

Graduate Theses and Dissertations

Insider threat causes great damage to data in any organization and is considered a serious issue. In spite of the presence of threat prevention mechanisms, sophisticated insiders still continue to attack a database with new techniques. One such technique which remains an advantage for insiders to attack databases is the dependency relationship among data items. This thesis investigates the ways by which an authorized insider detects dependencies in order to perform malicious write operations. The goal is to monitor malicious write operations performed by an insider by taking advantage of dependencies. A term called `threshold' is associated with every data …


Method And Apparatus For Rapid Identification Of Column Heterogeneity, Bing Tian Dai, Nikolaos Koudas, Beng Chin Ooi, Divesh Srivastava, Suresh Venkatasubranmanian May 2012

Method And Apparatus For Rapid Identification Of Column Heterogeneity, Bing Tian Dai, Nikolaos Koudas, Beng Chin Ooi, Divesh Srivastava, Suresh Venkatasubranmanian

Research Collection School Of Computing and Information Systems

A method and apparatus for rapid identification of column heterogeneity in databases are disclosed. For example, the method receives data associated with a column in a database. The method computes a cluster entropy for the data as a measure of data heterogeneity and then determines whether said data is heterogeneous in accordance with the cluster entropy.


Organizing User Search Histories, Heasoo Hwang, Hady W. Lauw, Lise Getoor, Alexandros Ntoulas May 2012

Organizing User Search Histories, Heasoo Hwang, Hady W. Lauw, Lise Getoor, Alexandros Ntoulas

Research Collection School Of Computing and Information Systems

Users are increasingly pursuing complex task-oriented goals on the web, such as making travel arrangements, managing finances, or planning purchases. To this end, they usually break down the tasks into a few codependent steps and issue multiple queries around these steps repeatedly over long periods of time. To better support users in their long-term information quests on the web, search engines keep track of their queries and clicks while searching online. In this paper, we study the problem of organizing a user's historical queries into groups in a dynamic and automated fashion. Automatically identifying query groups is helpful for a …


Spatial Queries In Wireless Broadcast Environments [Keynote Speech], Kyriakos Mouratidis May 2012

Spatial Queries In Wireless Broadcast Environments [Keynote Speech], Kyriakos Mouratidis

Research Collection School Of Computing and Information Systems

Wireless data broadcasting is a promising technique for information dissemination that exploits the computational capabilities of mobile devices, in order to enhance the scalability of the system. Under this environment, the data are continuously broadcast by the server, interleaved with some indexing information for query processing. Clients may tune in the broadcast channel and process their queries locally without contacting the server. In this paper we focus on spatial queries in particular. First, we review existing methods on this topic. Next, taking shortest path computation as an example, we showcase technical challenges arising in this processing model and describe techniques …


Spalendar: Visualizing A Group's Calendar Events Over A Geographic Space On A Public Display, Chen Xiang, Sebastian Boring, Sheelagh Carpendale, Anthony Tang, Saul Greenberg May 2012

Spalendar: Visualizing A Group's Calendar Events Over A Geographic Space On A Public Display, Chen Xiang, Sebastian Boring, Sheelagh Carpendale, Anthony Tang, Saul Greenberg

Research Collection School Of Computing and Information Systems

Portable paper calendars (i.e., day planners and organizers) have greatly influenced the design of group electronic calendars. Both use time units (hours/days/weeks/etc.) to organize visuals, with useful information (e.g., event types, locations, attendees) usually presented as - perhaps abbreviated or even hidden - text fields within those time units. The problem is that, for a group, this visual sorting of individual events into time buckets conveys only limited information about the social network of people. For example, people’s whereabouts cannot be read ‘at a glance’ but require examining the text. Our goal is to explore an alternate visualization that can …


Pamr: Passive-Aggressive Mean Reversion Strategy For Portfolio Selection, Bin Li, Peilin Zhao, Steven C. H. Hoi, Vivekanand Gopalkrishnan May 2012

Pamr: Passive-Aggressive Mean Reversion Strategy For Portfolio Selection, Bin Li, Peilin Zhao, Steven C. H. Hoi, Vivekanand Gopalkrishnan

Research Collection School Of Computing and Information Systems

This project proposes a novel online portfolio selection strategy named ``Passive Aggressive Mean Reversion" (PAMR). Unlike traditional trend following approaches, the proposed approach relies upon the mean reversion relation of financial markets. Equipped with online passive aggressive learning technique from machine learning, the proposed portfolio selection strategy can effectively exploit the mean reversion property of markets. By analyzing PAMR's update scheme, we find that it nicely trades off between portfolio return and volatility risk and reflects the mean reversion trading principle. We also present several variants of PAMR algorithm, including a mixture algorithm which mixes PAMR and other strategies. We …


Design And Construction Of An Entity Resolution System That Supports Entity Identity Information Management And Asserted Resolution, Eric D. Nelson Apr 2012

Design And Construction Of An Entity Resolution System That Supports Entity Identity Information Management And Asserted Resolution, Eric D. Nelson

Theses and Dissertations

This work describes the design and construction of an open source, entity resolution system that enables users to assign and maintain persistent identifiers for master data items. Two key features of this system that are not available in current ER systems and that make persistent identification possible are (1) The capture and management of entity identity information (2) Support for user-directed asserted resolution to complement automated direct matching and transitive closure Another important feature of the design is that the system can be easily configured at run-time into any one of four types of entity resolution architectures including * Traditional …


User Expectations Of Library Genealogy Databases V. What They Actually Get, Rosemary L. Meszaros, Katherine Pennavaria Apr 2012

User Expectations Of Library Genealogy Databases V. What They Actually Get, Rosemary L. Meszaros, Katherine Pennavaria

DLPS Faculty Publications

An analysis and comparison of two genealogical databases: Ancestry.com and Heritagequest.com.


Asynchronous Ultrasonic Trilateration For Indoor Positioning Of Mobile Phones, Viacheslav Filonenko, Charlie Cullen, James Carswell Apr 2012

Asynchronous Ultrasonic Trilateration For Indoor Positioning Of Mobile Phones, Viacheslav Filonenko, Charlie Cullen, James Carswell

Conference papers

In this paper we discuss how the innate ability of mobile phone speakers to produce ultrasound can be used for accurate indoor positioning. The frequencies in question are in a range between 20 and 22 KHz, which is high enough to be inaudible by humans but still low enough to be generated by today’s mobile phone sound hardware. Our tests indicate that it is possible to generate the given range of frequencies without significant distortions, provided the signal volume is not turned excessively high. In this paper we present and evaluate the accuracy of our asynchronous trilateration method (Lok8) for …


Effects Of Variations In 3d Spatial Search Techniques On Mobile Query Speed Vs Accuracy, Junjun Yin, James Carswell Apr 2012

Effects Of Variations In 3d Spatial Search Techniques On Mobile Query Speed Vs Accuracy, Junjun Yin, James Carswell

Conference papers

This paper presents three Spatial Search Algorithms for determiningthe three dimensional visibility shape (threat dome) at a user’s current locationin a built environment. Users then utilize this 3D shape as their query“window” to retrieve information on only those objects visible within a spatialdatabase. Visibility shape searching addresses the information overloadproblem by providing “Hidden Query Removal” functionality for mobile LBS.This functionality will be especially useful in the Web 4.0 era when trillions ofmicro-sensors become available for query through standard IP access.


Access Controls In Relational Databases, Rebekah Broome Apr 2012

Access Controls In Relational Databases, Rebekah Broome

Senior Seminars

There are many companies of all sizes that use databases to keep their data organized and easy to access. Databases have multiple parts, such as domains and constraints, Database Management System, and Metadata that make them unique. Not only does this paper cover the elements of a database but more specifically the elements of relational databases. This paper will go over the definition of relation databases, what makes this kind of database unique with the relation between tables, and how Standard Query Language is used by relational database. Then the paper will move on to the access controls that are …


Motivated Learning For The Development Of Autonomous Agents, Janusz A. Starzyk, James T. Graham, Pawel Raif, Ah-Hwee Tan Apr 2012

Motivated Learning For The Development Of Autonomous Agents, Janusz A. Starzyk, James T. Graham, Pawel Raif, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

A new machine learning approach known as motivated learning (ML) is presented in this work. Motivated learning drives a machine to develop abstract motivations and choose its own goals. ML also provides a self-organizing system that controls a machine’s behavior based on competition between dynamically-changing pain signals. This provides an interplay of externally driven and internally generated control signals. It is demonstrated that ML not only yields a more sophisticated learning mechanism and system of values than reinforcement learning (RL), but is also more efficient in learning complex relations and delivers better performance than RL in dynamically changing environments. In …


Detecting Extreme Rank Anomalous Collections, Hanbo Dai, Feida Zhu, Ee-Peng Lim, Hwee Hwa Pang Apr 2012

Detecting Extreme Rank Anomalous Collections, Hanbo Dai, Feida Zhu, Ee-Peng Lim, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

Anomaly or outlier detection has a wide range of applications, including fraud and spam detection. Most existing studies focus on detecting point anomalies, i.e., individual, isolated entities. However, there is an increasing number of applications in which anomalies do not occur individually, but in small collections. Unlike the majority, entities in an anomalous collection tend to share certain extreme behavioral traits. The knowledge essential in understanding why and how the set of entities becomes outliers would only be revealed by examining at the collection level. A good example is web spammers adopting common spamming techniques. To discover this kind of …


Mining Social Dependencies In Dynamic Interaction Networks, Freddy Chong-Tat Chua, Hady W. Lauw, Ee Peng Lim Apr 2012

Mining Social Dependencies In Dynamic Interaction Networks, Freddy Chong-Tat Chua, Hady W. Lauw, Ee Peng Lim

Research Collection School Of Computing and Information Systems

User-to-user interactions have become ubiquitous in Web 2.0. Users exchange emails, post on newsgroups, tag web pages, co-author papers, etc. Through these interactions, users co-produce or co-adopt content items (e.g., words in emails, tags in social bookmarking sites). We model such dynamic interactions as a user interaction network, which relates users, interactions, and content items over time. After some interactions, a user may produce content that is more similar to those produced by other users previously. We term this effect social dependency, and we seek to mine from such networks the degree to which a user may be socially dependent …


Obfuscating The Topical Intention In Enterprise Text Search, Hwee Hwa Pang, Xiaokui Xiao, Jialie Shen Apr 2012

Obfuscating The Topical Intention In Enterprise Text Search, Hwee Hwa Pang, Xiaokui Xiao, Jialie Shen

Research Collection School Of Computing and Information Systems

The text search queries in an enterprise can reveal the users' topic of interest, and in turn confidential staff or business information. To safeguard the enterprise from consequences arising from a disclosure of the query traces, it is desirable to obfuscate the true user intention from the search engine, without requiring it to be re-engineered. In this paper, we advocate a unique approach to profile the topics that are relevant to the user intention. Based on this approach, we introduce an (ε 1, ε 2)-privacy model that allows a user to stipulate that topics relevant to her intention …


Structural Analysis In Multi-Relational Social Networks, Bing Tian Dai, Freddy Chong Tat Chua, Ee-Peng Lim Apr 2012

Structural Analysis In Multi-Relational Social Networks, Bing Tian Dai, Freddy Chong Tat Chua, Ee-Peng Lim

Research Collection School Of Computing and Information Systems

Modern social networks often consist of multiple relationsamong individuals. Understanding the structureof such multi-relational network is essential. In sociology,one way of structural analysis is to identify differentpositions and roles using blockmodels. In thispaper, we generalize stochastic blockmodels to GeneralizedStochastic Blockmodels (GSBM) for performing positionaland role analysis on multi-relational networks.Our GSBM generalizes many different kinds of MultivariateProbability Distribution Function (MVPDF) tomodel different kinds of multi-relational networks. Inparticular, we propose to use multivariate Poisson distributionfor multi-relational social networks. Our experimentsshow that GSBM is able to identify the structuresfor both synthetic and real world network data.These structures can further be used for predicting …


Evaluating The Effect Of Smart Parking Technology On Campus Parking System Efficiency Using Discrete Event Simulation, Glenn Phillip Surpris Apr 2012

Evaluating The Effect Of Smart Parking Technology On Campus Parking System Efficiency Using Discrete Event Simulation, Glenn Phillip Surpris

Doctoral Dissertations and Master's Theses

This study was conducted to investigate the effect of smart parking systems (SPS) on parking search times (PST) in large parking lots. SPSs are systems that disseminate real-time parking spot availability to drivers searching for parking. The literature review revealed discrete event simulation (DES) to be a suitable tool for studying the dynamic behavior in parking lots. The parking lot selected for data collection was a university parking lot with 234 spaces. The data collected included arrival rates, departure rates, the geometric properties of the parking lot, preferred parking search strategies, and driving speeds. Arena 13.9, by Rockwell Automation, Inc, …


Stochastic Analysis Of Horizontal Ip Scanning, Derek Leonard, Zhongmei Yao, Xiaoming Wang, Dmitri Loguinov Mar 2012

Stochastic Analysis Of Horizontal Ip Scanning, Derek Leonard, Zhongmei Yao, Xiaoming Wang, Dmitri Loguinov

Computer Science Faculty Publications

Intrusion Detection Systems (IDS) have become ubiquitous in the defense against virus outbreaks, malicious exploits of OS vulnerabilities, and botnet proliferation. As attackers frequently rely on host scanning for reconnaissance leading to penetration, IDS is often tasked with detecting scans and preventing them. However, it is currently unknown how likely an IDS is to detect a given Internet-wide scan pattern and whether there exist sufficiently fast scan techniques that can remain virtually undetectable at large-scale. To address these questions, we propose a simple analytical model for the window-expiration rules of popular IDS tools (i.e., Snort and Bro) and utilize a …


On Superposition Of Heterogeneous Edge Processes In Dynamic Random Graphs, Zhongmei Yao, Daren B. H. Cline, Dmitri Loguinov Mar 2012

On Superposition Of Heterogeneous Edge Processes In Dynamic Random Graphs, Zhongmei Yao, Daren B. H. Cline, Dmitri Loguinov

Computer Science Faculty Publications

This paper builds a generic modeling framework for analyzing the edge-creation process in dynamic random graphs in which nodes continuously alternate between active and inactive states, which represent churn behavior of modern distributed systems. We prove that despite heterogeneity of node lifetimes, different initial out-degree, non-Poisson arrival/failure dynamics, and complex spatial and temporal dependency among creation of both initial and replacement edges, a superposition of edge-arrival processes to a live node under uniform selection converges to a Poisson process when system size becomes sufficiently large. Due to the convoluted dependency and non-renewal nature of various point processes, this result significantly …


Localized Deconvolution: Characterizing Nmr-Based Metabolomics Spectroscopic Data Using Localized High-Throughput Deconvolution, Paul E. Anderson, Ajith H. Ranabahu, Deirdre A. Mahle, Nicholas V. Reo, Michael L. Raymer, Amit P. Sheth, Nicholas J. Delraso Mar 2012

Localized Deconvolution: Characterizing Nmr-Based Metabolomics Spectroscopic Data Using Localized High-Throughput Deconvolution, Paul E. Anderson, Ajith H. Ranabahu, Deirdre A. Mahle, Nicholas V. Reo, Michael L. Raymer, Amit P. Sheth, Nicholas J. Delraso

Kno.e.sis Publications

The interpretation of nuclear magnetic resonance (NMR) experimental results for metabolomics studies requires intensive signal processing and multivariate data analysis techniques. Standard quantification techniques attempt to minimize effects from variations in peak positions caused by sample pH, ionic strength, and composition. These techniques fail to account for adjacent signals which can lead to drastic quantification errors. Attempts at full spectrum deconvolution have been limited in adoption and development due to the computational resources required. Herein, we develop a novel localized deconvolution algorithm for general purpose quantification of NMR-based metabolomics studies. Localized deconvolution decreases average absolute quantification error by 97% and …


Quality And Leniency In Online Collaborative Rating Systems, Hady W. Lauw, Ee Peng Lim, Ke Wang Mar 2012

Quality And Leniency In Online Collaborative Rating Systems, Hady W. Lauw, Ee Peng Lim, Ke Wang

Research Collection School Of Computing and Information Systems

The emerging trend of social information processing has resulted in Web users’ increased reliance on user-generated content contributed by others for information searching and decision making. Rating scores, a form of user-generated content contributed by reviewers in online rating systems, allow users to leverage others’ opinions in the evaluation of objects. In this article, we focus on the problem of summarizing the rating scores given to an object into an overall score that reflects the object’s quality. We observe that the existing approaches for summarizing scores largely ignores the effect of reviewers exercising different standards in assigning scores. Instead of …


Road: A New Spatial Object Search Framework For Road Networks, Ken C. K. Lee, Wang-Chien Lee, Baihua Zheng, Yuan Tian Mar 2012

Road: A New Spatial Object Search Framework For Road Networks, Ken C. K. Lee, Wang-Chien Lee, Baihua Zheng, Yuan Tian

Research Collection School Of Computing and Information Systems

In this paper, we present a new system framework called ROAD for spatial object search on road networks. ROAD is extensible to diverse object types and efficient for processing various location-dependent spatial queries (LDSQs), as it maintains objects separately from a given network and adopts an effective search space pruning technique. Based on our analysis on the two essential operations for LDSQ processing, namely, network traversal and object lookup, ROAD organizes a large road network as a hierarchy of interconnected regional subnetworks (called Rnets). Each Rnet is augmented with 1) shortcuts and 2) object abstracts to accelerate network traversals and …


Decision-Making Models, Decision Support And Problem Solving, Mark R. Lehto, Fiona Fui-Hoon Nah, Ji Soo Yi Mar 2012

Decision-Making Models, Decision Support And Problem Solving, Mark R. Lehto, Fiona Fui-Hoon Nah, Ji Soo Yi

Research Collection School Of Computing and Information Systems

This chapter focuses on the broad topic of human decision making. Decision making is often viewed as a stage of human information processing because people must gather, organize, and combine information from various sources to make decisions. However, as decisions grow more complex, information processing actually becomes part of decision making, and methods of decision sup-port that help decision makers process information become of growing importance. Decision making also overlaps with problem solving. The point where decision making becomes problem solving is fuzzy, but many decisions require problem solving, and the opposite is true as well. Cognitive models of problem …


Framework For The Analysis Of Coordination In Crisis Response, Hemant Purohit, Andrew Hampton, Valerie L. Shalin, Amit P. Sheth, John M. Flach Feb 2012

Framework For The Analysis Of Coordination In Crisis Response, Hemant Purohit, Andrew Hampton, Valerie L. Shalin, Amit P. Sheth, John M. Flach

Kno.e.sis Publications

Social Media play a critical role during crisis events, revealing a natural coordination dynamic. We propose a computational framework guided by social science principles to measure, analyze, and understand coordination among the different types of organizations and actors in crisis response. The analysis informs both the scientific account of cooperative behavior and the design of applications and protocols to support crisis management.


The Social Network Of Software Engineering Research, Subhajit Datta, Nishant Kumar, Santonu Sarkar Feb 2012

The Social Network Of Software Engineering Research, Subhajit Datta, Nishant Kumar, Santonu Sarkar

Research Collection School Of Computing and Information Systems

The social network perspective has served as a useful framework for studying scientific research collaboration in different disciplines. Although collaboration in computer science research has received some attention, software engineering research collaboration has remained unexplored to a large extent. In this paper, we examine the collaboration networks based on co-authorship information of papers from ten software engineering publication venues over the 1976-2010 time period. We compare time variations of certain parameters of these networks with corresponding parameters of collaboration networks from other disciplines. We also explore whether software engineering collaboration networks manifest symptoms of the small-world phenomenon, conform to the …


Extreme Learning Machine Terrain-Based Navigation For Unmanned Aerial Vehicles, Ee May Kan, Meng Hiot Lim, Yew Soon Ong, Ah-Hwee Tan, Swee Ping Yeo Feb 2012

Extreme Learning Machine Terrain-Based Navigation For Unmanned Aerial Vehicles, Ee May Kan, Meng Hiot Lim, Yew Soon Ong, Ah-Hwee Tan, Swee Ping Yeo

Research Collection School Of Computing and Information Systems

Unmanned aerial vehicles (UAVs) rely on global positioning system (GPS) information to ascertain its position for navigation during mission execution. In the absence of GPS information, the capability of a UAV to carry out its intended mission is hindered. In this paper, we learn alternative means for UAVs to derive real-time positional reference information so as to ensure the continuity of the mission. We present extreme learning machine as a mechanism for learning the stored digital elevation information so as to aid UAVs to navigate through terrain without the need for GPS. The proposed algorithm accommodates the need of the …


Mitigating The True Cost Of Advertisement-Supported "Free" Mobile Applications, Azeem J. Khan, Vigneshwaran Subbaraju, Archan Misra, Srinivasan Seshan Feb 2012

Mitigating The True Cost Of Advertisement-Supported "Free" Mobile Applications, Azeem J. Khan, Vigneshwaran Subbaraju, Archan Misra, Srinivasan Seshan

Research Collection School Of Computing and Information Systems

The dominant, "ad-supported free application" model for consumer-oriented mobile computing is seemingly imperiled by the growing global adoption of metered data pricing plans by mobile operators. In this paper, we explore the opportunities for addressing this emerging conflict by enabling more intelligent ad delivery to such mobile devices. One especially promising path is leveraging the increasing availability of heterogeneous wireless access technologies (e.g., WiFi, femtocells) that offer less restrictive and more energy-efficient transport substrates for such data traffic. To understand the possibilities that exist, we first profile the advertisement traffic characteristics for some of the most popular advertisement-supported consumer applications, …


An Examination Of Coordination Among Friends And Strangers From A Coordination Theory Perspective, Christopher D. Wamble Jan 2012

An Examination Of Coordination Among Friends And Strangers From A Coordination Theory Perspective, Christopher D. Wamble

Theses

Within mobile social coordination, there is a field of study known as outeraction, the communicative processes used by people to manage future interactions. It is an important area of research because it identifies how informal interactions support complex collaboration between individuals and groups. Outeraction is primarily conducted through the interpersonal communication channels of texting, instant messaging (IM), face-to-face, and mobile phone or Skype conversations. Currently this area of research in mobile outeraction support systems is weak. It lacks a firm foundation in system building, has very few if any conceptual frameworks, and little empirical knowledge of user requirements and attitudes …


Discovering Fine-Grained Sentiment In Suicide Notes, Wenbo Wang, Lu Chen, Ming Tan, Shaojun Wang, Amit P. Sheth Jan 2012

Discovering Fine-Grained Sentiment In Suicide Notes, Wenbo Wang, Lu Chen, Ming Tan, Shaojun Wang, Amit P. Sheth

Kno.e.sis Publications

This paper presents our solution for the i2b2 sentiment classification challenge. Our hybrid system consists of machine learning and rule-based classifiers. For the machine learning classifier, we investigate a variety of lexical, syntactic and knowledge-based features, and show how much these features contribute to the performance of the classifier through experiments. For the rule-based classifier, we propose an algorithm to automatically extract effective syntactic and lexical patterns from training examples. The experimental results show that the rule-based classifier outperforms the baseline machine learning classifier using unigram features. By combining the machine learning classifier and the rule-based classifier, the hybrid system …