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.

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 …

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 …

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 …

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 …

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 …