Physical Sciences and Mathematics Commons^™

Reachability And Turn Constraint Paths, Sabrina Wallace

UNLV Theses, Dissertations, Professional Papers, and Capstones

Problems dealing with the development of efficient algorithms for constructing collision-free paths have been explored extensively. We review existing algorithms for constructing collision-free paths under turn-angle constraints. We examine the problem of computing collision-free paths in the presence of polygonal obstacles. We present an algorithm for identifying the placement of a source vertex so that the maximum number of obstacle vertices can be reached via the shortest path tree under turn-angle requirements. We also present some experimental results on the construction of collision-free paths in the presence of polygonal obstacles.

Quantum Grover's Oracles With Symmetry Boolean Functions, Peng Gao

Dissertations and Theses

Quantum computing has become an important research field of computer science and engineering. Among many quantum algorithms, Grover's algorithm is one of the most famous ones. Designing an effective quantum oracle poses a challenging conundrum in circuit and system-level design for practical application realization of Grover's algorithm.

In this dissertation, we present a new method to build quantum oracles for Grover's algorithm to solve graph theory problems. We explore generalized Boolean symmetric functions with lattice diagrams to develop a low quantum cost and area efficient quantum oracle. We study two graph theory problems: cycle detection of undirected graphs and generalized …

Leveraging Model Flexibility And Deep Structure: Non-Parametric And Deep Models For Computer Vision Processes With Applications To Deep Model Compression, Anthony D. Rhodes

Dissertations and Theses

My dissertation presents several new algorithms incorporating non-parametric and deep learning approaches for computer vision and related tasks, including object localization, object tracking and model compression. With respect to object localization, I introduce a method to perform active localization by modeling spatial and other relationships between objects in a coherent "visual situation" using a set of probability distributions. I further refine this approach with the Multipole Density Estimation with Importance Clustering (MIC-Situate) algorithm. Next, I formulate active, "situation" object search as a Bayesian optimization problem using Gaussian Processes. Using my Gaussian Process Context Situation Learning (GP-CL) algorithm, I demonstrate improved …

Multiple Diagram Navigation, Hisham Benotman

Dissertations and Theses

Domain novices learning about a new subject can struggle to find their way in large collections. Typical searching and browsing tools are better utilized if users know what to search for or browse to. In this dissertation, we present Multiple Diagram Navigation (MDN) to assist domain novices by providing multiple overviews of the content matter using multiple diagrams. Rather than relying on specific types of visualizations, MDN superimposes any type of diagram or map over a collection of documents, allowing content providers to reveal interesting perspectives of their content. Domain novices can navigate through the content in an exploratory way …

Selectivity And Robustness Of Sparse Coding Networks, Dylan M. Paiton, Charles Frye, Sheng Y. Lundquist, Joel D. Bowen, Ryan Zarcone, Bruno A. Olshausen

Computer Science Faculty Publications and Presentations

We investigate how the population nonlinearities resulting from lateral inhibition and thresholding in sparse coding networks influence neural response selectivity and robustness. We show that when compared to pointwise nonlinear models, such population nonlinearities improve the selectivity to a preferred stimulus and protect against adversarial perturbations of the input. These findings are predicted from the geometry of the single-neuron iso-response surface, which provides new insight into the relationship between selectivity and adversarial robustness. Inhibitory lateral connections curve the iso-response surface outward in the direction of selectivity. Since adversarial perturbations are orthogonal to the iso-response surface, adversarial attacks tend to be …

Sequentially-Closed And Forward-Closed String Rewriting Systems, Yu Zhang

Legacy Theses & Dissertations (2009 - 2024)

In this dissertation we introduce the new concept of sequentially-closed string rewriting systems which generalizes forward-closed string rewriting systems and monadic string rewriting systems. We also investigate subclasses and properties of finite and regular sequentially-closed systems and forward-closed systems.

The Silencing Power Of Algorithms: How The Facebook News Feed Algorithm Manipulates Users' Perceptions Of Opinion Climates, Callie Jessica Morgan

University Honors Theses

This extended literature review investigates how the architecture and features of the Facebook Newsfeed algorithm, EdgeRank, can inhibit and facilitate the expression of political opinions. This paper will investigate how Elisabeth Noelle-Neumann's theory on public opinion, Spiral of Silence, can be used to assess the Facebook news feed as a political opinion source that actively shapes users' perceptions of minority and majority opinion climates. The feedback loops created by the algorithm's criteria influences users' decisions to self-censor or express their political opinions with interpersonal connections and unfamiliar connections on the site.

An Efficient System For Subgraph Discovery, Aparna Joshi

Legacy Theses & Dissertations (2009 - 2024)

Subgraph discovery in a single data graph---finding subsets of vertices and edges satisfying a user-specified criteria---is an essential and general graph analytics operation with a wide spectrum of applications. Depending on the criteria, subgraphs of interest may correspond to cliques of friends in social networks, interconnected entities in RDF data, or frequent patterns in protein interaction networks to name a few. Existing systems usually examine a large number of subgraphs while employing many computers and often produce an enormous result set of subgraphs. How can we enable fast discovery of only the most relevant subgraphs while minimizing the computational requirements?

On Problems Dual To Unification : The String-Rewriting Case, Zumrut Akcam Kibis

Legacy Theses & Dissertations (2009 - 2024)

Unification, with or without background theories such as associativity and commutativity,

Network Pruning For Scaling Dynamic Community Detection, Gaurav Ghosh

Legacy Theses & Dissertations (2009 - 2024)

Local community detection is an important tool for the analysis of networks of different genres. The goal is to identify only the best communities in a network instance as opposed to computing a partitioning of the whole network. The majority of the work on local community detection has focused on static networks with less attention on networks that evolve over time. Given a trace of temporal interaction among nodes in a network, how can we detect a period of high interaction for a specific group of nodes? To help temporal community detection with the need to search in the time …

Synchronous Subgraphs In Networks, Navita Jain

Legacy Theses & Dissertations (2009 - 2024)

Community detection is a central problem in network analysis. The majority of existing work defines communities as subsets of nodes that are structurally well-connected and isolated from the rest of the network. Apart from their underlying connectivity, nodes in real-world networks exhibit temporal activity: user posts in social networks, browsing activity on web pages and neuron activations in brain networks to name a few. While edges encode potential for community interactions, participation in the community can be quantified by synchronized member activity. Given both the network structure and individual node activity, how can we detect communities that are both well-connected …

Efficient Execution Of Top-K Closeness Centrality Queries, Paul W. Olsen

Legacy Theses & Dissertations (2009 - 2024)

Many of today's applications can benefit from the discovery of the most central entities in real-world networks.

A Theory Of Name Resolution, Pierre Néron, Andrew Tolmach, Eelco Visser, Guido Wachsmuth

Computer Science Faculty Publications and Presentations

We describe a language-independent theory for name binding and resolution, suitable for programming languages with complex scoping rules including both lexical scoping and modules. We formulate name resolution as a two-stage problem. First a language-independent scope graph is constructed using language-specific rules from an abstract syntax tree. Then references in the scope graph are resolved to corresponding declarations using a language-independent resolution process. We introduce a resolution calculus as a concise, declarative, and language- independent specification of name resolution. We develop a resolution algorithm that is sound and complete with respect to the calculus. Based on the resolution calculus we …

Concurrent Localized Wait-Free Operations On A Red Black Tree, Vitaliy Kubushyn

UNLV Theses, Dissertations, Professional Papers, and Capstones

A red-black tree is a type of self-balancing binary search tree. Some wait-free algorithms have been proposed for concurrently accessing and modifying a red-black tree from multiple threads in shared memory systems. Most algorithms presented utilize the concept of a "window", and are entirely top-down implementations. Top-down algorithms like these have to operate on large portions of the tree, and operations on nodes that would otherwise not overlap at all still have to compete with and help one another.

A wait-free framework is proposed for obtaining ownership of small portions of the tree at a time in a bottom-up manner. …

Using The Web 1t 5-Gram Database For Attribute Selection In Formal Concept Analysis To Correct Overstemmed Clusters, Guymon Hall

UNLV Theses, Dissertations, Professional Papers, and Capstones

Information retrieval is the process of finding information from an unstructured collection of data. The process of information retrieval involves building an index, commonly called an inverted file. As part of the inverted file, information retrieval algorithms often stem words to a common root. Stemming involves reducing a document term to its root. There are many ways to stem a word: affix removal and successor variety are two common categories of stemmers. The Porter Stemming Algorithm is a suffix removal stemmer that operates as a rule-based process on English words. We can think of stemming as a way to cluster …

Implementing Influence Diagram Concepts To Optimize Border Patrol Operations Using Unmanned Aerial Vehicles, Ashish Karki

UNLV Theses, Dissertations, Professional Papers, and Capstones

The most common approach for border patrol operations is the use of human personnel and manned ground vehicles, which is expensive, at times inefficient and sometimes even hazardous to people involved. The length of the US border, mostly covering unpopulated areas, with harsh atmospheric conditions makes it more susceptible to illegal human activities. Automated border surveillance by unattended, fixed, ground sensors forming an electronic fence has proven expensive, inefficient and was prone to unacceptable rate of false alarms.

A better approach would be using Unmanned Aerial Vehicles (UAVs) in combination with such ground sensors. This would help improve the overall …

A Survey Of Tabu Search In Combinatorial Optimization, Lemasri Piniganti

UNLV Theses, Dissertations, Professional Papers, and Capstones

Tabu search is a Meta heuristic loosely connected to evolutionary computing. It has been used to tackle hard problems, especially combinatorial optimization problems. Tabu search is designed to overcome difficult regions of a search space by imposing restrictions. Various methods for diversification and intensification are applied depending on the particular problem type and on what type of solutions (within the set of good solutions) are sought. Tabu search uses memory - short term, long term and intermediate - to achieve diversification and intensification. Furthermore, aspiration criteria may be used to tune the optimization process.

Thus the Tabu search Meta heuristic …

A Light-Weight Real-Time Privacy Protection Scheme For Video Surveillance By Unmanned Aircraft Systems, Surendra Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Unmanned Aircraft Systems (UAS)have raised a great concern on privacy recently. A practical method to protect privacy is needed for adopting UAS in civilian airspace. This thesis examines the privacy policies, filtering strategies, existing techniques, then proposes a new method based on encrypted video stream and cloud-based privacy servers. In this scheme, all video surveillance images are initially encrypted, then delivered to a privacy server. The privacy server decrypts the video using the shared key with the camera, and filters the image according to the privacy policy specified for the surveyed region. The sanitized video is delivered to the surveillance …

Scheduling Jobs On Two Uniform Parallel Machines To Minimize The Makespan, Sandhya Kodimala

UNLV Theses, Dissertations, Professional Papers, and Capstones

The problem of scheduling n independent jobs on m uniform parallel machines such that the total completion time is minimized is a NP-Hard problem. We propose several heuristic-based online algorithms for machines with different speeds called Q₂||C_max. To show the efficiency of the proposed online algorithms, we compute the optimal solution for Q₂||C_max using pseudo-polynomial algorithms based on dynamic programming method. The pseudo-polynomial algorithm has time complexity O (n T²) and can be run on reasonable time for small number of jobs and small processing times. This optimal offline algorithm is …

Calibration Of Traffic Flow Models, Victor Molano

College of Engineering: Graduate Celebration Programs

This study proposes a methodology to calibrate microscopic traffic flow simulation models. A Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm searches for the set of model parameters that minimizes the difference between actual and simulated values

Fast Sobel Edge Detection Using Parallel Pipeline-Based Architecture On Fpga, Mohammad Shokrolah Shirazi, Brendan Morris

College of Engineering: Graduate Celebration Programs

Implementing image processing algorithms on FPGA has recently become more popular since it provides high speed in comparison with software-based approaches. In this paper, we have presented fast pipeline-based architecture for one of the most popular edge detection algorithms called Sobel edge detection. The objective of our work is to present two fast pipeline-based architectures for Sobel edge detection on FPGA benefiting one and two way parallelism. We used Verilog language to implement our designs and we synthesized each one for Cyclone IV FPGA. Experimental results show that our pipeline-based architectures perform edge detection process more than 379 and 751 …

Alternative Hull Detection Techniques For Preprocessing In Proton Computed Tomography Reconstruction, Blake Edward Schultze

Theses Digitization Project

The purpose of this study was to develop computationally efficient hull detection techniques appropriate for image reconstruction using sparse matrices. The hull detection techniques investigated were space carving (SC), modified space carving (MSC), and space modeling (SM) and these were compared to the cone-beam version of filtered back projection (FBP) algorithm in terms of their computation time and the quality of the object hull they produced.

Quantum Cryptography, Razvan Augustin Dinu

Theses Digitization Project

This study builds a case for using a quantum computer for solving cryptographic problems. It looks at the quantum turing machine concept, explores why use quantum computers and presents Deutsch's problem which allows one to select from amongst the parallel paths a quantum computer calculates.

Message Passing Algorithm For Different Problems Sum, Mean, Guide And Sorting In A Rooted Tree Network., Sabaresh Nageswara Rao Maddula

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this thesis, we give message passing algorithms in distributed environment for five different problems of a rooted tree having n nodes. In the first algorithm, every node has a value; the root calculates the sum of those values, and sends it to all the nodes in the network. In the second algorithm, the root computes the value of mean of values of all the nodes, and sends it to all nodes of the network. The third algorithm calculates the guide pairs. Guide pair of a node x is an ordered pair (pre_index(x), post_index(x)), where pre_index(x) and post_index(x) are the …

Enhancing Trust In The Smart Grid By Applying A Modified Exponentially Weighted Averages Algorithm, Andrew T. Kasperek

Theses and Dissertations

The main contribution of this thesis is the development and application of a modified Exponentially Weighted Moving Algorithm (EWMA) algorithm, and its ability to robustly function in the face varying numbers of bad (malicious or malfunctioning) Special Protection System (SPS) nodes. Simulation results support the use of the proposed modified EWMA reputation based trust module in SPSs within a smart grid environment. This modification results in the ability to easily maintain the system above the minimum acceptable frequency of 58.8 Hz at the 95% confidence interval, when challenged with test cases containing 5, 10 and 15 bad node test cases …

A Global Positioning System On The Lunar Sphere Utilizing Cubesats, Armani Giann Batista

Theses Digitization Project

The purpose of this thesis was to research the viability and feasibility of a new Lunar GPS that would utilize the CubeSat platform, newly emerging technology, and the consideration of satellites without the large, currently employed, chemically atomic clocks.

Resizable, Scalable, Concurrent Hash Tables, Josh Triplett, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We present algorithms for shrinking and expanding a hash table while allowing concurrent, wait-free, linearly scalable lookups. These resize algorithms allow the hash table to maintain constant-time performance as the number of entries grows, and reclaim memory as the number of entries decreases, without delaying or disrupting readers.

We implemented our algorithms in the Linux kernel, to test their performance and scalability. Benchmarks show lookup scalability improved 125x over readerwriter locking, and 56% over the current state-of-the-art for Linux, with no performance degradation for lookups during a resize.

To achieve this performance, this hash table implementation uses a new concurrent …

Hardware Acceleration Of Inference Computing: The Numenta Htm Algorithm, Dan Hammerstrom

Systems Science Friday Noon Seminar Series

In this presentation I will describe the latest version of the Numenta HTM Cortical Learning Algorithm and why it is interesting for doing research into radical new computer architectures. Then I will discuss the hardware acceleration research we are doing, and briefly look at some preliminary applications development.

Reordered Subsets Reconstruction Of Proton Computed Tomography, Wenzhe Xue

Theses Digitization Project

This project investigates the improvement of iterative reconstruction using reordered subsets. Block iterative projection and Ordered Subset reconstruction algorithms are developed to improve the performance of image reconstruction. Contains source code.

Beyond Regular : Pattern Matching With Extended Regular Expressions, Benjamin Robert Carle

Legacy Theses & Dissertations (2009 - 2024)

Regular expression pattern matching or some variant thereof is present