Computer Sciences Commons^™

Petarxiv: An Archive For Scientific Simulations In Petashare, Tyler Barker

Honors Capstones

No abstract provided.

Breaking The Multi Colored Box: A Study Of Captcha, Sumit Khanna

Masters Theses and Doctoral Dissertations

Communication is faster than ever. Innovations in low cost network computing have brought an era in which people can effortlessly and instantaneously view and post opinions collaboratively with others across the world. With such an infrastructure of public message boards, chat rooms and instant messaging systems, there is also a large potential for abuse by people wishing to capitalize on such open services by posting unsolicited advertisements. An entire industry has been constructed around the prevention of unsolicited electronic advertisements (SPAM). This thesis examines various techniques for preventing SPAM, focusing on Completely Automated Public Turing Tests to Tell Computers and …

Semsos: Semantic Sensor Observation Service, Cory Andrew Henson, Josh Pschorr, Amit P. Sheth, Krishnaprasad Thirunarayan

Kno.e.sis Publications

Sensor observation service (SOS) is a Web service specification defined by the Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) group in order to standardize the way sensors and sensor data are discovered and accessed on the Web. This standard goes a long way in providing interoperability between repositories of heterogeneous sensor data and applications that use this data. Many of these applications, however, are ill equipped at handling raw sensor data as provided by SOS and require actionable knowledge of the environment in order to be practically useful. There are two approaches to deal with this obstacle, make the …

My Guild, My Team: Applying The Technology Capabilities Of Massively Multiplayer Online Games To Virtual Project Teams, Dawn Owens, Deepak Khazanchi

Information Systems and Quantitative Analysis Faculty Proceedings & Presentations

Millions of people are playing Massively Multiplayer Online Games (MMOGs), a computer game genre where thousands of players interact daily in highly complex virtual world environments. These players self-organize, develop skills, and acquire various roles. MMOGs appear to mirror the complexity of the business context while offering unique technology capabilities that appear to encourage group participation and emergent leadership. Managing a remote workforce across different time zones, geography and culture requires effective virtual collaboration and management of communication, coordination challenges and control issues. Therefore, the purpose of this paper is to explore the unique technology capabilities of MMOGs and propose …

Incremental Validation Of Formal Specifications, Paul S. Corwin

Master's Theses

This thesis presents a tool for the mechanical validation of formal software specifications. The tool is based on a novel approach to incremental validation. In this approach, small-scale aspects of a specification are validated, as part of the stepwise refinement of a formal model.

The incremental validation technique can be considered a form of "lightweight" model checking. This is in contrast to a "heavyweight" approach, wherein an entire large-scale model is validated en masse.

The validation tool is part of a formal modeling and specification language (FMSL), used in software engineering instruction. A lightweight, incremental approach to validation is beneficial …

Pairing Software-Managed Caching With Decay Techniques To Balance Reliability And Static Power In Next-Generation Caches, Kelly Shaw, Margaret Martonosi

Department of Math & Statistics Technical Report Series

Since array structures represent well over half the area and transistors on-chip, maintaining their ability to scale is crucial for overall technology scaling. Shrinking transistor sizes are resulting in increased probabilities of single events causing single- and multi-bit upsets which require adoption of more complex and power hungry error detection and correction codes (ECC) in hardware. At the same time, SRAM leakage energy is increasing partly due to technology trends and partly due to the increasing number of transistors present.

This paper proposes and evaluates methods of reducing the static power requirements of caches, while also maintaining high reliability. In …

The Effects Of Carbon Nanotubes On Cpu Cooling, Sashi Kiran Challa

Masters Theses and Doctoral Dissertations

Computers today have evolved from being big bulky machines that took up rooms of space into small simple machines for net browsing and into small but complicated multi-core servers and supercomputing architectures. This has been possible due to the evolution of the processors. Today processors have reached 45nm specifications with millions of transistors. Transistors produce heat when they run. Today more than ever we have a growing need for managing this heat efficiently. It is indicated that increasing power density can cause a difficulty in managing temperatures on a chip. It is also mentioned that we need to move to …

Ss-Ids: Statistical Signature Based Ids, Payas Gupta, Chedy Raissi, Gerard Dray, Pascal Poncelet, Johan Brissaud

Research Collection School Of Computing and Information Systems

Security of web servers has become a sensitive subject today. Prediction of normal and abnormal request is problematic due to large number of false alarms in many anomaly based Intrusion, Detection Systems(IDS). SS-IDS derives automatically the parameter profiles from the analyzed data thereby generating the Statistical Signatures. Statistical Signatures are based on modeling of normal requests and their distribution value without explicit intervention. Several attributes are used to calculate the behavior of the legitimate request on the web server. SS-IDS is best suited for the newly installed web servers which doesn't have low gene number of requests in. the data …

A Survey Of Monge Properties, Swetha Sethumadhavan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Monge properties play an important role in theoretical computer science. Many greedy algorithms are based on such properties, as is speedup in dynamic programming. Monge properties are simple monotonicity properties which are observed and used in various settings such as resource optimization, computational geometry, statistical sampling, computational biology and coding.

Autoscopy: Detecting Pattern-Searching Rootkits Via Control Flow Tracing, Ashwin Ramaswamy

Dartmouth College Master’s Theses

Traditional approaches to rootkit detection assume the execution of code at a privilege level below that of the operating system kernel, with the use of virtual machine technologies to enable the detection system itself to be immune from the virus or rootkit code. In this thesis, we approach the problem of rootkit detection from the standpoint of tracing and instrumentation techniques, which work from within the kernel and also modify the kernel's run-time state to detect aberrant control flows. We wish to investigate the role of emerging tracing frameworks (Kprobes, DTrace etc.) in enforcing operating system security without the reliance …

A Study Of Relevance Feedback In Vector Space Model, Deepthi Katta

UNLV Theses, Dissertations, Professional Papers, and Capstones

Information Retrieval is the science of searching for information or documents based on information need from a huge set of documents. It has been an active field of research since early 19^th century and different models of retrieval came in to existence to cater the information need.

This thesis starts with understanding some of the basic information retrieval models, followed by implementation of one of the most popular statistical retrieval model known as Vector Space Model. This model ranks the documents in the collection based on the similarity measure calculated between the query and the respective document. The user …

Evaluating The Use Of Snmp As A Wireless Network Monitoring Tool For Ieee 802.11 Wireless Networks, Robert Johnson

All Theses

The increasing popularity of wireless networks has led to instances of high utilization and congestion, some of which have resulted in an interruption of network service. A thorough understanding of how IEEE 802.11 wireless networks operate is crucial to predicting and preventing future interruptions. There have been many studies performed on wireless networks. Of those that have captured data from the wireless side, most have used a form of wireless network monitoring known as Vicinity Sniffing (wireless sniffing from a location that is physically close to an access point to be in the broadcast range) as the primary means of …

Ocular Vergence Response Over Anaglyphic Stereoscopic Videos, Brian Daugherty

All Theses

The effect of anaglyphic stereographic stimuli on ocular vergence response is examined. An experiment is performed comparing ocular vergence response induced by anaglyphic stereographic display versus standard monoscopic display. Two visualization tools, synchronized three-dimensional scanpath playback and real-time dynamic heatmap generation,
are developed and used to subjectively support the quantitative analysis of ocular disparity. The results of a one-way ANOVA indicate that there is a highly significant effect of anaglyphic stereoscopic display on ocular vergence for a majority of subjects although consistency of vergence response is difficult to predict.

Teaching Specifications Using An Interactive Reasoning Assistant, Dana Leonard

All Theses

The importance of verifiably correct software has grown enormously in recent years as software has become integral to the design of critical systems, including airplanes, automobiles, and medical equipment. Hence, the importance of solid analytical reasoning skills to complement basic programming skills has also increased. If developers cannot reason about the software they design, they cannot ensure the correctness of the resulting systems. And if these systems fail, the economic and human costs can be substantial.
In addition to learning analytical reasoning principles as part of the standard Computer Science curriculum, students must be excited about learning these skills and …

How Tagging Helps Bridge The Gap Between Social And Technical Aspects In Software Development, Christoph Treude, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

Empirical research on collaborative software development practices indicates that technical and social aspects of software development are often intertwined. The processes followed are tacit and constantly evolving, thus not all of them are amenable to formal tool support. In this paper, we explore how ldquotaggingrdquo, a lightweight social computing mechanism, is used to bridge the gap between technical and social aspects of managing work items. We present the results from an empirical study on how tagging has been adopted and adapted over the past two years of a large project with 175 developers. Our research shows that the tagging mechanism …

Distributed Constraint Optimization With Structured Resource Constraints, Akshat Kumar, Boi Faltings, Adrian Petcu

Research Collection School Of Computing and Information Systems

Distributed constraint optimization (DCOP) provides a framework for coordinated decision making by a team of agents. Often, during the decision making, capacity constraints on agents' resource consumption must be taken into account. To address such scenarios, an extension of DCOP-Resource Constrained DCOP - has been proposed. However, certain type of resources have an additional structure associated with them and exploiting it can result in more efficient algorithms than possible with a general framework. An example of these are distribution networks, where the flow of a commodity from sources to sinks is limited by the flow capacity of edges. We present …

On Mining Rating Dependencies In Online Collaborative Rating Networks, Hady W. Lauw, Ee Peng Lim, Ke Wang

Research Collection School Of Computing and Information Systems

The trend of social information processing sees e-commerce and social web applications increasingly relying on user-generated content, such as rating, to determine the quality of objects and to generate recommendations for users. In a rating system, a set of reviewers assign to a set of objects different types of scores based on specific evaluation criteria. In this paper, we seek to determine, for each reviewer and for each object, the dependency between scores on any two given criteria. A reviewer is said to have high dependency between a pair of criteria when his or her rating scores on objects based …

Zeros And Ones, M. Thulasidas

Research Collection School Of Computing and Information Systems

Computers are notorious for their infuriatingly literal obedience. I am sure anyone who has ever worked with a computer has come across the lack of empathy on its part – it follows our instructions to the dot, yet ends up accomplishing something altogether different from what we intend. Let’s spare a thought for the way your glorified adding machine makes sense of things

Predicting Outcome For Collaborative Featured Article Nomination In Wikipedia, Meiqun Hu, Ee Peng Lim, Ramayya Krishnan

Research Collection School Of Computing and Information Systems

In Wikipedia, good articles are wanted. While Wikipedia relies on collaborative effort from online volunteers for quality checking, the process of selecting top quality articles is time consuming. At present, the duty of decision making is shouldered by only a couple of administrators. Aiming to assist in the quality checking cycles so as to cope with the exponential growth of online contributions to Wikipedia, this work studies the task of predicting the outcome of featured article (FA) nominations. We analyze FA candidate (FAC) sessions collected over a period of 3.5 years, and examine the extent to which consensus has been …

Turn Constrained Path Planning Problems, Victor M. Roman

UNLV Theses, Dissertations, Professional Papers, and Capstones

We consider the problem of constructing multiple disjoint paths connecting a source point s to a target point t in a geometric graph. We require that the paths do not have any sharp turn angles. We present a review of turn constrained path planning algorithms and also algorithms for constructing disjoint paths. We then combine these techniques and present an O(nlogn) time algorithm for constructing a pair of edge disjoint turn constrained paths connecting two nodes in a planar geometric graph. We also consider the development of a turn constrained shortest path map in the presence of …

Predicting Rna Secondary Structures By Folding Simulation: Software And Experiments, Joel Omni Gillespie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We present a new method for predicting the secondary structure of RNA sequences. Using our method, each RNA nucleotide of an RNA Sequence is represented as a point on a 3D triangular lattice. Using the Simulated Annealing technique, we manipulate the location of the points on the lattice. We explore various scoring functions for judging the relative quality of the structures created by these manipulations. After near optimal configurations on the lattice have been found, we describe how the lattice locations of the nucleotides can be used to predict a secondary structure for the sequence. This prediction can be further …

Optimal Candidate Generation In Spatial Co-Location Mining, Zhongshan Lin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Existing spatial co-location algorithms based on levels suffer from generating extra, nonclique candidate instances. Thus, they require cliqueness checking at every level. In this thesis, a novel, spatial co-location mining algorithm that automatically generates co-located spatial features without generating any nonclique candidates at any level is proposed. Subsequently, this algorithm generates fewer candidates than other existing level-wise, co-location algorithms without losing any pertinent information. The benefits of this algorithm have been clearly observed at early stages in the mining process.

Covert Botnet Implementation And Defense Against Covert Botnets, Lokesh Babu Ramesh Babu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The advent of the Internet and its benevolent use has benefited mankind in private and business use alike. However, like any other technology, the Internet is often used for malevolent purposes. One such malevolent purpose is to attack computers using botnets. Botnets are stealthy, and the victims are typically unaware of the malicious activities and the resultant havoc they can cause. Computer security experts seek to combat the botnet menace. However, attackers come up with new botnet designs that exploit the weaknesses in existing defense mechanisms and, thus, continue to evade detection.

Therefore, it is necessary to analyze the weaknesses …

A Computational Geometry Approach To Digital Image Contour Extraction, Pedro J. Tejada

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We present a method for extracting contours from digital images, using techniques from computational geometry. Our approach is different from traditional pixel-based methods in image processing. Instead of working directly with pixels, we extract a set of oriented feature points from the input digital images, then apply classical geometric techniques, such as clustering, linking, and simplification, to find contours among these points. Experiments on synthetic and natural images show that our method can effectively extract contours, even from images with considerable noise; moreover, the extracted contours have a very compact representation.

A Methodology To Design Pipelined Simulated Annealing Kernel Accelerators On Space-Borne Field-Programmable Gate Arrays, Jeffrey Michael Carver

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Increased levels of science objectives expected from spacecraft systems necessitate the ability to carry out fast on-board autonomous mission planning and scheduling. Heterogeneous radiation-hardened Field Programmable Gate Arrays (FPGAs) with embedded multiplier and memory modules are well suited to support the acceleration of scheduling algorithms. A methodology to design circuits specifically to accelerate Simulated Annealing Kernels (SAKs) in event scheduling algorithms is shown. The main contribution of this thesis is the low complexity scoring calculation used for the heuristic mapping algorithm used to balance resource allocation across a coarse-grained pipelined data-path. The methodology was exercised over various kernels with different …

Object Trajectory Estimation Using Optical Flow, Shuo Liu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Object trajectory tracking is an important topic in many different areas. It is widely used in robot technology, traffic, movie industry, and others. Optical flow is a useful method in the object tracking branch and it can calculate the motion of each pixel between two frames, and thus it provides a possible way to get the trajectory of objects. There are numerous papers describing the implementation of optical flow. Some results are acceptable, but in many projects, there are limitations. In most previous applications, because the camera is usually static, it is easy to apply optical flow to identify the …

Semisupervised Svm Batch Mode Active Learning With Applications To Image Retrieval, Steven C. H. Hoi, Rong Jin, Jianke Zhu, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Active learning has been shown as a key technique for improving content-based image retrieval (CBIR) performance. Among various methods, support vector machine (SVM) active learning is popular for its application to relevance feedback in CBIR. However, the regular SVM active learning has two main drawbacks when used for relevance feedback. First, SVM often suffers from learning with a small number of labeled examples, which is the case in relevance feedback. Second, SVM active learning usually does not take into account the redundancy among examples, and therefore could select multiple examples in relevance feedback that are similar (or even identical) to …

Sharing Hierarchical Mobile Multimedia Content Using The Mobitop System, Quang Minh Nguyen, Thi Nhu Quynh Kim, Dion Hoe-Lian Goh, Ee-Peng Lim, Yin-Leng Theng, Kalyani Chatterjea, Chew-Hung Chang, Aixin Sun, Khasfariyati Razikin

Research Collection School Of Computing and Information Systems

We introduce MobiTOP (Mobile Tagging of Objects and People), a map-based application which allows users to contribute and share geo-referenced multimedia annotations via mobile devices. An important feature of MobiTOP is that annotations are hierarchical, allowing annotations to be annotated to an arbitrary depth. MobiTOP's interface was designed using a participatory design methodology to ensure that the user interface meets the needs of potential users. In an evaluation, a group of student-teachers involved in a geographical field study were tasked to collaboratively identify rock formations using the MobiTOP system. The students who were in the field were guided by their …

Constraint-Based Dynamic Programming For Decentralized Pomdps With Structured Interactions, Akshat Kumar, Shlomo Zilberstein

Research Collection School Of Computing and Information Systems

Decentralized partially observable MDPs (DEC-POMDPs) provide a rich framework for modeling decision making by a team of agents. Despite rapid progress in this area, the limited scalability of solution techniques has restricted the applicability of the model. To overcome this computational barrier, research has focused on restricted classes of DEC-POMDPs, which are easier to solve yet rich enough to capture many practical problems. We present CBDP, an efficient and scalable point-based dynamic programming algorithm for one such model called ND-POMDP (Network Distributed POMDP). Specifically, CBDP provides magnitudes of speedup in the policy computation and generates better quality solution for all …

Dynamic Programming Approximations For Partially Observable Stochastic Games, Akshat Kumar, Shlomo Zilberstein

Research Collection School Of Computing and Information Systems

Partially observable stochastic games (POSGs) provide a rich mathematical framework for planning under uncertainty by a group of agents. However, this modeling advantage comes with a price, namely a high computational cost. Solving POSGs optimally quickly becomes intractable after a few decision cycles. Our main contribution is to provide bounded approximation techniques, which enable us to scale POSG algorithms by several orders of magnitude. We study both the POSG model and its cooperative counterpart, DEC-POMDP. Experiments on a number of problems confirm the scalability of our approach while still providing useful policies.