Physical Sciences and Mathematics Commons^™

An Exploratory Study Of High Performance Graphics Application Programming Interfaces, Joseph A. Shiraef

Masters Theses and Doctoral Dissertations

This study was conducted to take an in depth look at the newest APIs offered to graphics programmers. With the recent releases of Vulkan (2016) and DirectX 12 (2015) from industry giants like the Khronos Group and Microsoft, it’s clear they are pushing for a much lower-level, closer-to-hardware approach for future graphics programming solutions. These changes can be credited to the drastic improvements we’ve seen in graphics processors over the last 5 years. It will take a significant amount of time for these API’s to become industry standard. The goal of this research is to verify the value and benefits …

Harsh And Variable Ecological Conditions Modulate The Relationship Between Social Structure And Direct Fitness In A Plurally Breeding Small Mammal, Kathleen Anne Carroll

Masters Theses and Doctoral Dissertations

Evidence suggests that harsh and variable environmental conditions modulate the fitness benefits associated with increased group size in some species. Social network analysis is a more powerful approach to examine this relationship, as the quality of interactions is more important than quantity. Using 9 years of data, I determined how mean and coefficient of variation (CV) of nine ecological variables modulated the relationship between social network metrics on direct fitness in the plurally breeding rodent, Octodon degus. As predicted, increased social structure was most beneficial when food abundance was more variable, mean monthly rainfall was highest, predator abundance was more …

Hdidx: High-Dimensional Indexing For Efficient Approximate Nearest Neighbor Search, Ji Wan, Sheng Tang, Yongdong Zhang, Jintao Li, Pengcheng Wu, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

Fast Nearest Neighbor (NN) search is a fundamental challenge in large-scale data processing and analytics, particularly for analyzing multimedia contents which are often of high dimensionality. Instead of using exact NN search, extensive research efforts have been focusing on approximate NN search algorithms. In this work, we present "HDIdx", an efficient high-dimensional indexing library for fast approximate NN search, which is open-source and written in Python. It offers a family of state-of-the-art algorithms that convert input high-dimensional vectors into compact binary codes, making them very efficient and scalable for NN search with very low space complexity.

Domain-Specific Cross-Language Relevant Question Retrieval, Bowen Xu, Zhenchang Xing, Xin Xia, David Lo, Qingye Wang, Shanping Li

Research Collection School Of Computing and Information Systems

In software development process, developers often seek solutions to the technical problems they encounter by searching relevant questions on Q&A sites. When developers fail to find solutions on Q&A sites in their native language (e.g., Chinese), they could translate their query and search on the Q&A sites in another language (e.g., English). However, developers who are non-native English speakers often are not comfortable to ask or search questions in English, as they do not know the proper translation of the Chinese technical words into the English technical words. Furthermore, the process of manually formulating cross-language queries and determining the weight …

A Key-Insulated Cp-Abe With Key Exposure Accountability For Secure Data Sharing In The Cloud, Hanshu Hong, Zhixin Sun, Ximeng Liu

Research Collection School Of Computing and Information Systems

ABE has become an effective tool for data protection in cloud computing. However, since users possessing the same attributes share the same private keys, there exist some malicious users exposing their private keys deliberately for illegal data sharing without being detected, which will threaten the security of the cloud system. Such issues remain in many current ABE schemes since the private keys are rarely associated with any user specific identifiers. In order to achieve user accountability as well as provide key exposure protection, in this paper, we propose a key-insulated ciphertext policy attribute based encryption with key exposure accountability (KI-CPABE-KEA). …

Efspredictor: Predicting Configuration Bugs With Ensemble Feature Selection, Bowen Xu, David Lo, Xin Xia, Ashish Sureka, Shanping Li

Research Collection School Of Computing and Information Systems

The configuration of a system determines the system behavior and wrong configuration settings can adversely impact system's availability, performance, and correctness. We refer to these wrong configuration settings as configuration bugs. The importance of configuration bugs has prompted many researchers to study it, and past studies can be grouped into three categories: detection, localization, and fixing of configuration bugs. In the work, we focus on the detection of configuration bugs, in particular, we follow the line-of-work that tries to predict if a bug report is caused by a wrong configuration setting. Automatically prediction of whether a bug is a configuration …

Algorithmic Problems Arising In Posets And Permutations, Shahrzad Haddadan

Dartmouth College Ph.D Dissertations

Partially ordered sets and permutations are combinatorial structures having vast applications in theoretical computer science. In this thesis, we study various computational and algorithmic problems related to these structures. The first chapter of the thesis contains discussion about randomized fully polynomial approximation schemes obtained by employing Markov chain Monte Carlo. In this chapter we study various Markov chains that we call: the gladiator chain, the interval chain, and cube shuffling. Our objective is to identify some conditions that assure rapid mixing; and we obtain partial results. The gladiator chain is a biased random walk on the set of permutations. This …

Privacy-Preserving Controls For Sharing Mhealth Data, Aarathi Prasad

Dartmouth College Ph.D Dissertations

Mobile devices allow people to collect and share health and health-related information with recipients such as health providers, family and friends, employers and insurance companies, to obtain health, emotional or financial benefits. People may consider certain health information sensitive and prefer to disclose only what is necessary. In this dissertation, we present our findings about factors that affect people’s sharing behavior, describe scenarios in which people may wish to collect and share their personal health-related information with others, but may be hesitant to disclose the information if necessary controls are not available to protect their privacy, and propose frameworks to …

Constraint-Based Robot Knot Tying, Weifu Wang

Dartmouth College Ph.D Dissertations

In this thesis, we present different approaches to tying knots using robots by enforcing different types of constraints. We attack the problem from three different directions; mechanical design, motion planning with simple control strategies, and theoretical analysis. We present the first complete generalized fixture based knot tying approach that is able to arrange and tighten knots, building on Matthew Bell’s work on arranging simple knots using fixtures [Bel10]. Physical constraints are provided by these fixtures to reduce the possible string deformation during knot tying. Fixtures are designed automatically using proposed design principles, and constructed based on the designs using 3D …

Activity Pattern Discovery From Network Captures, Alan C. Lin, Gilbert L. Peterson

Faculty Publications

Investigating insider threat cases is challenging because activities are conducted with legitimate access that makes distinguishing malicious activities from normal activities difficult. To assist with identifying non-normal activities, we propose using two types of pattern discovery to identify a person's behavioral patterns in network data. The behavioral patterns serve to deemphasize normal behavior so that insider threat investigations can focus attention on potentially more relevant. Results from a controlled experiment demonstrate the highlighting of a suspicious event through the reduction of events belonging to discovered patterns. Abstract © 2016 IEEE.

The Eagle Programming Language, Samuel G. Horlbeck Olsen

Mathematics, Statistics, and Computer Science Honors Projects

C remains the dominant systems programming language despite many new languages attempting to take its place. Modern languages generally value abstraction and safety over speed and direct control of hardware. They are therefore not well suited to the low-level tasks for which C was designed. This paper introduces a novel programming language, Eagle, which represents a fast, elegant alternative to C. It allows low-level programming while providing optional modern features like reference counting, closures, generators, and classes. In addition to specifying this language and reviewing the current alternatives, the paper describes the implementation of a working Eagle compiler. The language …

Bases For Mckay Centralizer Algebras, Lucas Gagnon

Mathematics, Statistics, and Computer Science Honors Projects

The finite subgroups of the special unitary group SU2 have been classified to be isomorphic to one of the following groups: cyclic, binary dihedral, binary tetrahedral, binary octahedral, and binary icosahedral, of order n, 4n, 24, 48, and 120, respectively. Associated to each group is a representation graph, which by the McKay correspondence is a Dynkin diagram of type Aˆ n−1, Dˆ n+2, Eˆ 6, Eˆ 7, or Eˆ 8. The centralizer algebra Zk(G) = EndG(V ⊗k ) is the algebra of transformations that commute with G acting on the k-fold tensor product of the defining representation V = C …

Building Voters: Exploring Interdependent Preferences In Binary Contexts, Ian Calaway

Mathematics, Statistics, and Computer Science Honors Projects

In this thesis we develop a new method for constructing binary preference orders for given interdependent structures, called characters. We introduce the preference space, which is a vector space of preference vectors. The preference vectors correspond to binary preference orders. We show that the hyperoctahedral group, Z2 o Sn, describes the symmetries of binary preferences orders and then define an action of Z2 o Sn on our preference vectors. We find a natural basis for a preference space. These basis vectors are indexed by subsets of proposals. We show that when completely separable binary preference vectors are decomposed using this …

Global Supply Sets In Graphs, Christian G. Moore

Electronic Theses and Dissertations

For a graph G=(V,E), a set S⊆V is a global supply set if every vertex v∈V\S has at least one neighbor, say u, in S such that u has at least as many neighbors in S as v has in V \S. The global supply number is the minimum cardinality of a global supply set, denoted γgs (G). We introduce global supply sets and determine the global supply number for selected families of graphs. Also, we give bounds on the global supply number for general graphs, trees, and grid graphs.

Immobilization Of Heteropolyacids In Silica Gel, Opeyemi Adetola

Electronic Theses and Dissertations

Silica gels containing incorporated heteropolyacids (HPAs) were synthesized in acidic media by co-condensation of tetraethoxysilane (TEOS) with phosphotungstic or phosphomolybdic acids using sol-gel technique. Effect of the synthesis conditions on their structure and morphology was studied. Yields of modified materials were some lower as compared to non-modified silica gels. All materials were mesoporous but contained micropores in their structures. Presence of bands of Keggin’s structures in FT-IR spectra along with absence of XRD patterns of crystalline HPAs confirmed their fine incorporation into silica network. Particle sizes of modified materials were 800-1100 nm excepting for W-containing sample obtained with trimethylstearylammonium chloride. …

Peccaries (Artiodactyla: Tayassuidae) From The Late Miocene To Early Pliocene Gray Fossil Site: Regional Implications With A Review Of Tayassuinae, Evan M. Doughty

Electronic Theses and Dissertations

Analysis of the Gray Fossil Site peccary material indicates the presence of up to three species. Comparisons with the tayassuid material known from the Tyner Farm and Bone Valley Formation of Florida allows the identification of Mylohyus elmorei and at the GFS. Within the GFS material, Prosthennops cf. P. serus and cf. Catagonus sp. are also tentatively recognized but further verification is required. The known range for Prosthennops is expanded into the Appalachian region. Presence of M. elmorei at the Gray Fossil Site provides the first known occurrence of this species outside of the Palmetto fauna of Florida, indicating that …

Investigating Mineral Stability Under Venus Conditions: A Focus On The Venus Radar Anomalies, Erika Kohler

Graduate Theses and Dissertations

Radar studies of the surface of Venus have identified regions with high radar reflectivity concentrated in the Venusian highlands: between 2.5 and 4.75 km above a planetary radius of 6051 km, though it varies with latitude. Previous research has proposed several theories on the source of these anomalies, including increased surface roughness, metallic materials with higher dielectric constants, or ferroelectric materials. Prior work suggests several processes that could be the origin of these anomalies, such as surface-atmospheric interactions or low lying clouds or fog. Alternatively, these anomalies could result from a semi-metallic compound trapped at the cooler conditions in the …

Placental ‘€˜Omics’€™ Study To Understand The Pathogenesis Of Preeclampsia, Komal Kedia

Theses and Dissertations

Preeclampsia (PE) is a potentially fatal complication of pregnancy characterized by an increase in blood pressure (>140/90 mmHg) and proteinuria (>300 mg/24 hrs), often accompanied by edema. Symptoms of PE start after 20 weeks of gestation. If PE remains untreated, it can lead to eclampsia, grand-mal seizures responsible for most fatalities. PE is believed to affect 2-10% of pregnancies worldwide, and claims the lives of over 75,000 mothers and 500,000 newborns yearly. No therapeutic agents have been developed to prevent or cure PE. Part of the reason for this is the absence of a complete understanding of the …

A Comparative Approach To Question Answering Systems, Josue Balandrano Coronel

Theses and Dissertations

In this paper I will analyze three different algorithms and approaches to implement Question Answering Systems (QA-Systems). I will analyze the efficiency, strengths, and weaknesses of multiple algorithms by explaining them in detail and comparing them with each other. The overarching aim of this thesis is to explore ideas that can be used to create a truly open context QA-System. Open context QA-Systems remain an open problem.

The various algorithms and approaches presented in this work will be focused on complex questions. Complex questions are usually verbose and the context of the question is equally important to answer the query …

Global Entropy Based Greedy Algorithm For Discretization, Sai Jyothsna Jonnalagadda

Theses and Dissertations

Discretization algorithm is a crucial step to not only achieve summarization of continuous attributes but also better performance in classification that requires discrete values as input. In this thesis, I propose a supervised discretization method, Global Entropy Based Greedy algorithm, which is based on the Information Entropy Minimization. Experimental results show that the proposed method outperforms state of the art methods with well-known benchmarking datasets. To further improve the proposed method, a new approach for stop criterion that is based on the change rate of entropy was also explored. From the experimental analysis, it is noticed that the threshold based …

Lie Symmetry To Nonlinear Oscillator Systems And Applications, Xiaoyan Li

Theses and Dissertations

In this paper, we apply the theory of Lie symmetry to study a generalized second-order nonlinear differential equation, which includes several physical nonlinear oscillators such as force-free Helmholtz oscillator, force-free Duffing and Duffing-van der Pol oscillators, modified Emden-type equation and its hierarchy etc, and investigate the dynamical properties of this rather general equation. We identify and classify several new integrable cases for arbitrary values of exponents, which determine the tangent vector as well as the infinitesimal generator. Using the Lie point symmetry, we find the useful infinitesimal generators and canonical coordinates, and obtain the first integrals of the second-order nonlinear …

On Hypergroups Of Order At Most 6, Jordy C. Lopez

Theses and Dissertations

This thesis surveys recent results on hypergroups as defined by Frédéric Marty in [3] and [4] and their relation to association schemes as presented in [5]. We show that every association scheme is a hypergroup. Then, we compile a few general results on hypergroups needed for our investigation of hypergroups with three, four and six elements. From [1] and [7], we give examples of hypergroups that do not come from finite schemes and from no scheme at all. Our main result occurs when considering hypergroups S with six elements that have a non-normal closed subset T of order 2 with …

Development Of A Phased Array Using Lnbs With Non-Synchronized Clocks, James I. Murray

Theses and Dissertations

A passive phased array is an array of antennas in which the phases of the signals on each element are controlled to be added to form a spatial beam. The advantage is that one can steer the beam without physically moving the constituent elements as well as create multiple beams on the sky simultaneously. This has application in the field of satellite and spacecraft communications where there is expected to be a large increase in satellite volume due to the increasing access to space. Traditional phased arrays can become costly to synchronize at satellite down-link frequencies, therefore we have built …

Identification Of Synthetic Chemical Compound Inhibitors Of Pseudomonas Aeruginosa Protein Synthesis And The Development Of Lead Series, Stephanie O. Palmer

Theses and Dissertations

Pseudomonas aeruginosa is a ubiquitous Gram-negative bacteria and a primary cause of nosocomial infections. An aminoacylation/translation (A/T) assay was developed using P. aeruginosa components to perform poly(U) mRNA directed protein synthesis. Using scintillation proximity assay (SPA) technology a high-throughput screening (HTS) platform was developed. A synthetic chemical compound library (>900) was screened, 36 hit compounds were identified and molecular targets were determined. Compounds were analyzed for enzymatic inhibition (IC50) and inhibition of bacterial cultures (MIC). Time-kill studies determined bacterial growth to be bacteriostatic or bactericidal in the presence of inhibitor. Mechanism of action, effects on eukaryotic cytosolic and mitochondrial …

Molecular Dynamic Simulation Studies Of The Androgen Receptor Complexed With 5Α-Dihydrotestosterone And An Allosteric Ligand, Everardo Villarreal Ii

Theses and Dissertations

Receptors are important drug targets for the pharmaceutical industry, since they are involved in many illnesses. Nuclear receptors are a subset of receptors that control a variety of physiological events, by expression of genes from DNA. One of the nuclear receptors, the androgen receptor, is a steroid binding receptor that controls a variety of regulatory and development functions in the body. It is also the cause of some types of cancer, so the inhibition of this receptor is crucial. One of the processes studied to inhibit the function of the receptor is to see if an allosteric ligand, TRIAC, can …

Analysis And Simulation Of A Social Network, Twitter: A Case Study, Jonatan Reyes

Theses and Dissertations

The use of online social networks empowers its users to efficiently disseminate information across traditional social networks. Typically, the weight and value of messages are relative to its readers’ culture and interests. Nevertheless, in some instances, messages take the form of viral phenomenon, which circulates around the world in very short periods of time. Therefore, despite the actual content of the message spread over the network, the determination of the effectiveness of message dissemination across the social network becomes an attractive opportunity for scientific study. Since a meticulous analysis of a complete online social network would require the acquisition of …

Hydrodesulfurization Of Dibenzothiophene Using Comos2, Jacob S. Sollner

Theses and Dissertations

The hydrodesulphurization (HDS) of crude oils is an important industrial process to remove sulfur from fuels. In this study, DBT was used as a model compound to study the removal of sulfur from a decahydronaphthalene solution. The catalyst was synthesized through low pressure pathways in the absence of H2S. All the synthesized catalyst were investigated using a combination of SEM, RAMAN spectroscopy, and XRD. The materials were studied for their ability to remove DBT from solution and the reaction products were analyzed. It was observed that the major reaction pathway was the direct desulphurization pathway and zero order reaction kinetics …

The Complete Structure Of Linear And Nonlinear Deformations Of Frames On A Hilbert Space, Devanshu Agrawal

Electronic Theses and Dissertations

A frame is a possibly linearly dependent set of vectors in a Hilbert space that facilitates the decomposition and reconstruction of vectors. A Parseval frame is a frame that acts as its own dual frame. A Gabor frame comprises all translations and phase modulations of an appropriate window function. We show that the space of all frames on a Hilbert space indexed by a common measure space can be fibrated into orbits under the action of invertible linear deformations and that any maximal set of unitarily inequivalent Parseval frames is a complete set of representatives of the orbits. We show …

Takens Theorem With Singular Spectrum Analysis Applied To Noisy Time Series, Thomas K. Torku

Electronic Theses and Dissertations

The evolution of big data has led to financial time series becoming increasingly complex, noisy, non-stationary and nonlinear. Takens theorem can be used to analyze and forecast nonlinear time series, but even small amounts of noise can hopelessly corrupt a Takens approach. In contrast, Singular Spectrum Analysis is an excellent tool for both forecasting and noise reduction. Fortunately, it is possible to combine the Takens approach with Singular Spectrum analysis (SSA), and in fact, estimation of key parameters in Takens theorem is performed with Singular Spectrum Analysis. In this thesis, we combine the denoising abilities of SSA with the Takens …

Strategies Of Balancing: Regulation Of Posture As A Complex Phenomenon, Allison Leich Hilbun

Electronic Theses and Dissertations

The complexity of the interface between the muscular system and the nervous system is still elusive. We investigated how the neuromuscular system functions and how it is influenced by various perturbations. Postural stability was selected as the model system, because this system provides complex output, which could indicate underlying mechanisms and feedback loops of the neuromuscular system. We hypothesized that aging, physical pain, and mental and physical perturbations affect balancing strategy, and based on these observations, we constructed a model that simulates many aspects of the neuromuscular system. Our results show that aging changes the control strategy of balancing from …