Computer Sciences Commons^™

Aggregate Nearest Neighbor Queries In Spatial Databases, Dimitris Papadias, Yufei Tao, Kyriakos Mouratidis, Chun Kit Hui

Research Collection School Of Computing and Information Systems

Given two spatial datasets P (e.g., facilities) and Q (queries), an aggregate nearest neighbor (ANN) query retrieves the point(s) of P with the smallest aggregate distance(s) to points in Q. Assuming, for example, n users at locations q1,...qn, an ANN query outputs the facility p belongs to P that minimizes the sum of distances |pqi| for 1 is less than or equal to i is less than or equal to n that the users have to travel in order to meet there. Similarly, another ANN query may report the point p belongs to P that minimizes the maximum distance that …

Learning Outcomes Oriented Assessment Methods In An Active Learning Environment, Arcot Desai Narasimhalu

Research Collection School Of Computing and Information Systems

Singapore Management University uses interactive seminar style teaching in class rooms. Most of its students hail from Singapore and are generally new to active learning and constructive participation in the seminar style classes. This paper reports findings from a freshmen first term course titled IS 101: Seminar for ISM Majors.

Breaking Public Key Cryptosystems On Tamper Resistant Devices In The Presence Of Transient Faults, Feng Bao, Robert H. Deng, Y. Han, A. Jeng, Arcot Desai Narasimhalu, T. Ngair

Research Collection School Of Computing and Information Systems

In this paper we present a method of attacking public-key cryptosystems (PKCs) on tamper resistant devices. The attack makes use of transient faults and seems applicable to many types of PKCs. In particular, we show how to attack the RSA, the E1Gamal signature scheme, the Schnorr signature scheme, and the DSA. We also present some possible methods to counter the attack.

Active Contours Using A Constraint-Based Implicit Representation, Weiming Liu, Bryan S. Morse, Kalpathi Subramanian, Terry S. Yoo

Faculty Publications

We present a new constraint-based implicit active contour, which shares desirable properties of both parametric and implicit active contours. Like parametric approaches, their representation is compact and can be manipulated interactively. Like other implicit approaches, they can naturally adapt to non-simple topologies. Unlike implicit approaches using level-set methods, representation of the contour does not require a dense mesh. Instead, it is based on specified on-curve and off-curve constraints, which are interpolated using radial basis functions. These constraints are evolved according to specified forces drawn from the relevant literature of both parametric and implicit approaches. This new type of active contour …

A Semi-Supervised Active Learning Framework For Image Retrieval, Steven Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Although recent studies have shown that unlabeled data are beneficial to boosting the image retrieval performance, very few approaches for image retrieval can learn with labeled and unlabeled data effectively. This paper proposes a novel semi-supervised active learning framework comprising a fusion of semi-supervised learning and support vector machines. We provide theoretical analysis of the active learning framework and present a simple yet effective active learning algorithm for image retrieval. Experiments are conducted on real-world color images to compare with traditional methods. The promising experimental results show that our proposed scheme significantly outperforms the previous approaches.

Knowledge Management Mechanisms Of Financial Service Sites, Fiona Fui-Hoon Nah, Keng Siau, Y. Tian

Research Collection School Of Computing and Information Systems

How can we effectively acquire, use, and manage knowledge via the Web?

Conceptual Partitioning: An Efficient Method For Continuous Nearest Neighbor Monitoring, Kyriakos Mouratidis, Marios Hadjieleftheriou, Dimitris Papadias

Research Collection School Of Computing and Information Systems

Given a set of objects P and a query point q, a k nearest neighbor (k-NN) query retrieves the k objects in P that lie closest to q. Even though the problem is well-studied for static datasets, the traditional methods do not extend to highly dynamic environments where multiple continuous queries require real-time results, and both objects and queries receive frequent location updates. In this paper we propose conceptual partitioning (CPM), a comprehensive technique for the efficient monitoring of continuous NN queries. CPM achieves low running time by handling location updates only from objects that fall in the vicinity of …

On Assigning Place Names To Geography Related Web Pages, Wenbo Zong, Dan Wu, Aixin Sun, Ee Peng Lim, Dion Hoe-Lian Goh

Research Collection School Of Computing and Information Systems

In this paper, we attempt to give spatial semantics to web pages by assigning them place names. The entire assignment task is divided into three sub-problems, namely place name extraction, place name disambiguation and place name assignment. We propose our approaches to address these sub-problems. In particular, we have modified GATE, a well-known named entity extraction software, to perform place name extraction using a US Census gazetteer. A rule-based place name disambiguation method and a place name assignment method capable of assigning place names to web page segments have also been proposed. We have evaluated our proposed disambiguation and assignment …

Evaluating G-Portal For Geography Learning And Teaching, Chew-Hung Chang, John G. Hedberg, Yin-Leng Theng, Ee Peng Lim, Tiong-Sa Teh, Dion Hoe-Lian Goh

Research Collection School Of Computing and Information Systems

This paper describes G-Portal, a geospatial digital library of geographical assets, providing an interactive platform to engage students in active manipulation and analysis of information resources and collaborative learning activities. Using a G-Portal application in which students conducted a field study of an environmental problem of beach erosion and sea level rise, we describe a pilot study to evaluate usefulness and usability issues to support the learning of geographical concepts, and in turn teaching.

Verifying Completeness Of Relational Query Results In Data Publishing, Hwee Hwa Pang, Arpit Jain, Krithi Ramamritham, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

In data publishing, the owner delegates the role of satisfying user queries to a third-party publisher. As the publisher may be untrusted or susceptible to attacks, it could produce incorrect query results. In this paper, we introduce a scheme for users to verify that their query results are complete (i.e., no qualifying tuples are omitted) and authentic (i.e., all the result values originated from the owner). The scheme supports range selection on key and non-key attributes, project as well as join queries on relational databases. Moreover, the proposed scheme complies with access control policies, is computationally secure, and can be …

Correspondence Expansion For Wide Baseline Stereo, Parris K. Egbert, Kevin L. Steele

Faculty Publications

We present a new method for generating large numbers of accurate point correspondences between two wide baseline images. This is important for structure-from-motion algorithms, which rely on many correct matches to reduce error in the derived geometric structure. Given a small initial correspondence set we iteratively expand the set with nearby points exhibiting strong affine correlation, and then we constrain the set to an epipolar geometry using RANSAC. A key point to our algorithm is to allow a high error tolerance in the constraint, allowing the correspondence set to expand into many areas of an image before applying a lower …

A Scenario-Based Performance Evaluation Of Multicast Routing Protocols For Ad Hoc Networks, Manoj Pandey, Daniel Zappala

Faculty Publications

Current ad hoc multicast routing protocols have been designed to build and maintain a tree or mesh in the face of a mobile environment, with fast reaction to network changes in order to minimize packet loss. However, the performance of these protocols has not been adequately examined under realistic scenarios. Existing performance studies generally use a single, simple mobility model, with low density and often very low traffic rates. In this paper we explore the performance of ad hoc multicast routing protocols under scenarios that include realistic mobility patterns, high density and high traffic load. We use these scenarios to …

An Evolutionary Algorithm To Generate Hyper-Ellipsoid Detectors For Negative Selection, Joseph M. Shapiro, Gary B. Lamont, Gilbert L. Peterson

Faculty Publications

This paper introduces hyper-ellipsoids as an improvement to hyper-spheres as intrusion detectors in a negative selection problem within an artificial immune system. Since hyper-spheres are a specialization of hyper-ellipsoids, hyper-ellipsoids retain the benefits of hyper-spheres. However, hyper-ellipsoids are much more flexible, mostly in that they can be stretched and reoriented. The viability of using hyper-ellipsoids is established using several pedagogical problems. We conjecture that fewer hyper-ellipsoids than hyper-spheres are needed to achieve similar coverage of nonself space in a negative selection problem. Experimentation validates this conjecture. In pedagogical benchmark problems, the number of hyper-ellipsoids to achieve good results is significantly …

The Effects Of Digital Audio On Social Presence, Motivation And Perceived Learning In Asynchronous Learning Networks, Eunhee Kim

Dissertations

This study explores the possibilities of applying digital audio to the ALN environment, so that students can speak and listen rather than type and read. Two sets of 1x2 field experiments (text vs. digital audio) were conducted with two formats of digital audio -recorded voice messages and narrated Microsoft PowerPoint presentation - used in several NJIT courses conducted via ALN. The perceptions of communication media were measured from two different user perspectives: active use when the subjects created their assignments using prescribed communication media (audio or text) and passive use when the subjects viewed/listened to other students' work.

The perceptions …

Some Topics On Deterministic Scheduling Problems, Yumei Huo

Dissertations

Sequencing and scheduling problems are motivated by allocation of limited resources over time. The goal is to find an optimal allocation where optimality is defined by some problem specific objectives.

This dissertation considers the scheduling of a set of ri tasks, with precedence constraints, on m >= 1 identical and parallel processors so as to minimize the makespan. Specifically, it considers the situation where tasks, along with their precedence constraints, are released at different times, and the scheduler has to make scheduling decisions without knowledge of future releases. Both preemptive and nonpreemptive schedules are considered. This dissertation shows that optimal …

Scheduling Policies For Disks And Disk Arrays, Chang Liu

Dissertations

Recent rapid advances of magnetic recording technology have enabled substantial increases in disk capacity. There has been less than 10% improvement annually in the random access time to small data blocks on the disk. Such accesses are very common in OLTP applications, which tend to have stringent response time requirements. Scheduling of disk requests is intended to improve their response time, reduce disk service time, and increase disk access bandwidth with respect to the default FCFS scheduling policy.

Shortest Access Time First policy has been shown to outperform other classical disk scheduling policies in numerous studies. Before verifying this conclusion, …

Image Watermarking, Steganography, And Morphological Processing, Yi-Ta Wu

Dissertations

With the fast development of computer technology, research in the fields of multimedia security, image processing, and robot vision have recently become popular. Image watermarking, steganogrphic system, morphological processing and shortest path planning are important subjects among them. In this dissertation, the fundamental techniques are reviewed first followed by the presentation of novel algorithms and theorems for these three subjects.

The research on multimedia security consists of two parts, image watermarking and steganographic system. In image watermarking, several algorithms are developed to achieve different goals as shown below. In order to embed more watermarks and to minimize distortion of watermarked …

Collaborative Examinations In Asyncronous Learning Networks : Field Experiments On Collaborative Learning Through Online Assessments, Jia Shen

Dissertations

With the proliferation of computer networks and the emergence of virtual teams, learning and knowledge sharing in the online environment has become an increasingly important topic. Applying constructivism and collaborative learning theories to assessment, the collaborative online exam is designed featuring students' active participation in various phases of the exam process through small group activities online. A participatory online exam process is designed featuring similar procedures except that students' involvement in each phase of the exam is individual. The collaborative online exam and the participatory online exam are investigated regarding student exam study strategies, group process, exam outcomes, faculty satisfaction, …

Algorithms And Complexity Analyses For Some Combinational Optimization Problems, Hairong Zhao

Dissertations

The main focus of this dissertation is on classical combinatorial optimization problems in two important areas: scheduling and network design.

In the area of scheduling, the main interest is in problems in the master-slave model. In this model, each machine is either a master machine or a slave machine. Each job is associated with a preprocessing task, a slave task and a postprocessing task that must be executed in this order. Each slave task has a dedicated slave machine. All the preprocessing and postprocessing tasks share a single master machine or the same set of master machines. A job may …

Just-In-Time Hypermedia, Li Zhang

Dissertations

Many analytical applications, especially legacy systems, create documents and display screens in response to user queries "dynamically" or in real time . These documents and displays do not exist in advance, and thus hypermedia must be generated 'just in time" -automatically and dynamically.

This dissertation details the idea of 'just-in-time" hypermedia and discusses challenges encountered in this research area. A fully detailed literature review about the research issues and related research work is given. A framework for the 'just-in-time" hypermedia compares virtual documents with static documents, as well as dynamic with static hypermedia functionality. Conceptual 'just-in-time" hypermedia architecture is proposed …

High-Dimensional Indexing Methods Utilizing Clustering And Dimensionality Reduction, Lijuan Zhang

Dissertations

The emergence of novel database applications has resulted in the prevalence of a new paradigm for similarity search. These applications include multimedia databases, medical imaging databases, time series databases, DNA and protein sequence databases, and many others. Features of data objects are extracted and transformed into high-dimensional data points. Searching for objects becomes a search on points in the high-dimensional feature space. The dissimilarity between two objects is determined by the distance between two feature vectors. Similarity search is usually implemented as nearest neighbor search in feature vector spaces. The cost of processing k-nearest neighbor (k-NN) queries via a sequential …

Improving Document Representation By Accumulating Relevance Feedback : The Relevance Feedback Accumulation (Rfa) Algorithm, Razvan Stefan Bot

Dissertations

Document representation (indexing) techniques are dominated by variants of the term-frequency analysis approach, based on the assumption that the more occurrences a term has throughout a document the more important the term is in that document. Inherent drawbacks associated with this approach include: poor index quality, high document representation size and the word mismatch problem. To tackle these drawbacks, a document representation improvement method called the Relevance Feedback Accumulation (RFA) algorithm is presented. The algorithm provides a mechanism to continuously accumulate relevance assessments over time and across users. It also provides a document representation modification function, or document representation learning …

Order Scheduling In Dedicated And Flexible Machine Environments, Haibing Li

Dissertations

Order scheduling models are relatively new in the field of scheduling. Consider a facility with m parallel machines that can process k different products (job types). Each machine can process a given subset of different product types. There are n orders from n different clients. Each order requests specific quantities of the various different products that can be produced concurrently on their given subsets of machines; it may have a release date, a weight and a due date. Preemptions may be allowed. An order can not be shipped until the processing of all the products for the order has been …

A Toy Rock Climbing Robot, Matthew P. Bell

Dartmouth College Undergraduate Theses

The goal of this thesis was to build a simple toy rock climbing robot, and to explore problems related to grasping, path planning, and robot control. The robot is capable of climbing a wall of pegs either under manual control through a host system and an infrared interface, or on the basis of a set of pre-recorded keyframes. In addition, the robot can climb certain peg configurations using a cyclic gait. The robot climbs in an open-loop mode without sensor feedback. All communications are sent through the IR connection, and the tether to the robot consists only of two power …

Energy Balanced Broadcasting Through Delayed Intelligence, Michael R. Gosnell, Ryan Arbarelli, Maggie Xiaoyan Cheng, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

Ad hoc wireless networks are growing in popularity and usefulness, however they rely on broadcasting as a fundamental process for routing. Improvements to broadcasting have made ad hoc networks more feasible, but sometimes benefit only specific situations. Delayed intelligence (DI) is proposed as a new load balancing approach where small delays are introduced to allow distributed responsibility delegation. Preliminary results show delayed intelligence, when applied in existing broadcasting methods such as passive clustering, can be used to improve the energy disparity and therefore extend ad hoc network lifetime.

Approximation Algorithms For Variants Of The Traveling Salesman Problem, Ankur Gupta

Theses

The traveling salesman problem, hereafter abbreviated and referred to as TSP, is a very well known NP-optimization problem and is one of the most widely researched problems in computer science. Classical TSP is one of the original NP - hard problems [1]. It is also known to be NP - hard to approximate within any factor and thus there is no approximation algorithm for TSP for general graphs, unless P = NP. However, given the added constraint that edges of the graph observe triangle inequality, it has been shown that it is possible achieve a good approximation to the optimal …

Rebuild Performance Enhancement Using Onboard Caching And Delayed Vacation Termination In Clustered Raid 5, Akheel Ahmed

Theses

The Clustered Raid 5 (CRAID5) architecture with a parity group size(G) smaller than the number of disks(N) increases the load by the declustering ratio denoted by α = (G -1)/(N -1), which can be lesser than that in Raid 5 while switching to, and subsequently operating in rebuild mode. The Nearly Random Permutation (NRP) layout provides the flexibility to vary the declustering ratio (α) for a given N, and the Vacationing Server Model (VSM) of processing the rebuild requests provides acceptable rebuild and user response times.

The rebuild performance and the user response time can be improved by introducing an …

Sharing The Big Apple : A Survey Study Of People, Place And Locatability, Samer Nadim Karam

Theses

Over the past half century social trends and new technologies have weakened local social ties and thus, the fabric of civil society itself. Mobile location-aware community systems offer one path to redress these problems by enhancing community cohesion and the formation of social capital by helping people to meet each other and coordinate their actions. However, little is known about the general population's desire and attitude towards these systems.

The design space described by the People-to-People-to-Geographical-Places Framework (P3-Framework), was used to guide a survey study of the impact of 'place' on people's social information needs and their willingness to share …

Structure And Dynamics Of Soluble Guanylyl Cyclase, Kentaro Sugino

Theses

Soluble guanylyl cyclase (sGC) is one of the key enzymes involved in many fundamental biological processes including vasodilatation. It can be allosterically activated by synthetic compound such as YC-l. Recently, the 3D structure of adenylyl cyclase (AC), which is a homologue of sGC, was determined. Using AC as template and homology modeling, the 3D structure of sGC is predicted. Prior experimental work has suggested two binding modes of YC- 1. In the current investigation, molecular dynamics simulations (MD) were conducted to seek more detail of molecular mechanism of sGC activation.

From these MD simulations, a tentative mechanism of sGC activation …

An Overview Of The Security Of Wireless Networks, Eduardo B. Fernandez, Imad Jawbar, Maria M. Larrondo-Petrie, Michael Van Hilst

CCE Faculty Books and Book Chapters

Handbook of Wireless Local Area Networks: Applications, Technology, Security, and Standards captures the current state of wireless LANs, and serves as the single comprehensive reference on the subject. Addressing challenges related to the further development of WLAN technology, the Handbook covers the entire spectrum of topics from basic concepts to research grade material.

Consisting of 25 articles contributed by expert authors from around the world, the Handbook begins with a detailed introduction that provides an overview of LAN technologies, performance, security, and security protocols. It then delves further into WLAN technology, covering space-time processing, WLAN and cellular convergence, and a …