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Full-Text Articles in Physical Sciences and Mathematics

Algorithms For Learning The Structure Of Monotone And Nonmonotone Sum-Product Networks, Aaron W. Dennis Dec 2016

Algorithms For Learning The Structure Of Monotone And Nonmonotone Sum-Product Networks, Aaron W. Dennis

Theses and Dissertations

The sum-product network (SPN) is a recently-proposed generative, probabilistic model that is guaranteed to compute any joint or any marginal probability in time linear in the size of the model. An SPN is represented as a directed, acyclic graph (DAG) of sum and product nodes, with univariate probability distributions at the leaves. It is important to learn the structure of this DAG since the set of distributions representable by an SPN is constrained by it. We present the first batch structure learning algorithm for SPNs and show its advantage over learning the parameters of an SPN with fixed architecture. We …


A Common Misconception In Multi-Label Learning, Michael Benjamin Brodie Nov 2016

A Common Misconception In Multi-Label Learning, Michael Benjamin Brodie

Theses and Dissertations

The majority of current multi-label classification research focuses on learning dependency structures among output labels. This paper provides a novel theoretical view on the purported assumption that effective multi-label classification models must exploit output dependencies. We submit that the flurry of recent dependency-exploiting, multi-label algorithms may stem from the deficiencies in existing datasets, rather than an inherent need to better model dependencies. We introduce a novel categorization of multi-label metrics, namely, evenly and unevenly weighted label metrics. We explore specific features that predispose datasets to improved classification by methods that model label dependence. Additionally, we provide an empirical analysis of …


Towards Using Certificate-Based Authentication As A Defense Against Evil Twins In 802.11 Networks, Travis S. Hendershot Nov 2016

Towards Using Certificate-Based Authentication As A Defense Against Evil Twins In 802.11 Networks, Travis S. Hendershot

Theses and Dissertations

Wireless clients are vulnerable to exploitation by evil twins due to flaws in the authentication process of 802.11 Wi-Fi networks. Current certificate-based wireless authentication protocols present a potential solution, but are limited in their ability to provide a secure and usable platform for certificate validation. Our work seeks to mitigate these limitations by exploring a client-side strategy for utilizing alternative trust models in wireless network authentication. We compile a taxonomy of various trust models for conducting certificate-based authentication of wireless networks and methodically evaluate each model according to desirable properties of security, usability, and deployability. We then build a platform …


Peering Through The Cloud—Investigating The Perceptions And Behaviors Of Cloud Storage Users, Justin Chun Wu Oct 2016

Peering Through The Cloud—Investigating The Perceptions And Behaviors Of Cloud Storage Users, Justin Chun Wu

Theses and Dissertations

We present the results of a survey and interviews focused on user perceptions and behaviors with respect to cloud storage services. In particular, we study behaviors such as which services are used, what types of data are stored, and how collaboration and sharing are performed. We also investigate user attitudes toward cloud storage on topics such as payment, privacy, security, and robustness. We find that users are drawn to cloud storage because it enables robust, ubiquitous access to their files, as well as enabling sharing and collaborative efforts. However, users' preferred medium for file sharing continues to be email, due …


Verification Of Task Parallel Programs Using Predictive Analysis, Radha Vi Nakade Oct 2016

Verification Of Task Parallel Programs Using Predictive Analysis, Radha Vi Nakade

Theses and Dissertations

Task parallel programming languages provide a way for creating asynchronous tasks that can run concurrently. The advantage of using task parallelism is that the programmer can write code that is independent of the underlying hardware. The runtime determines the number of processor cores that are available and the most efficient way to execute the tasks. When two or more concurrently executing tasks access a shared memory location and if at least one of the accesses is for writing, data race is observed in the program. Data races can introduce non-determinism in the program output making it important to have data …


The State Of Man-In-The-Middle Tls Proxies: Prevalence And User Attitudes, Mark Thomas Oneill Oct 2016

The State Of Man-In-The-Middle Tls Proxies: Prevalence And User Attitudes, Mark Thomas Oneill

Theses and Dissertations

We measure the prevalence and uses of Man-in-the-Middle TLS proxies using a Flash tool deployed with a Google AdWords campaign. We generate 15.2 million certificate tests across two large-scale measurement studies and find that 1 in 250 TLS connections are intercepted by proxies. The majority of these proxies appear to be benevolent, however we identify over 3,600 cases where eight malware products are using this technology nefariously. We also find thousands of instances of negligent, duplicitous, and suspicious behavior, some of which degrade security for users without their knowledge. Distinguishing these types of practices is challenging in practice, indicating a …


Creating And Automatically Grading Annotated Questions, Alicia Crowder Wood Sep 2016

Creating And Automatically Grading Annotated Questions, Alicia Crowder Wood

Theses and Dissertations

We have created a question type that allows teachers to easily create questions, helps provide an intuitive user experience for students to take questions, and reduces the time it currently takes teachers to grade and provide feedback to students. This question type, or an "annotated" question, will allow teachers to test students' knowledge in a particular subject area by having students "annotate" or mark text and video sources to answer questions. Through user testing we determined that overall the interface and the implemented system decrease the time it would take a teacher to grade annotated quiz questions. However, there are …


From Qualitative To Quantitative: Supporting Robot Understanding In Human-Interactive Path Planning, Daqing Yi Aug 2016

From Qualitative To Quantitative: Supporting Robot Understanding In Human-Interactive Path Planning, Daqing Yi

Theses and Dissertations

Improvements in robot autonomy are changing human-robot interaction from low-level manipulation to high-level task-based collaboration. When a robot can independently and autonomously executes tasks, a human in a human-robot team acts as a collaborator or task supervisor instead of a tele-operator. When applying this to planning paths for a robot's motion, it is very important that the supervisor's qualitative intent is translated into aquantitative model so that the robot can produce a desirable consequence. In robotic path planning, algorithms can transform a human's qualitative requirement into a robot's quantitative model so that the robot behavior satisfies the human's intent. In …


Usable, Secure Content-Based Encryption On The Web, Scott Ruoti Jul 2016

Usable, Secure Content-Based Encryption On The Web, Scott Ruoti

Theses and Dissertations

Users share private information on the web through a variety of applications, such as email, instant messaging, social media, and document sharing. Unfortunately, recent revelations have shown that not only is users' data at risk from hackers and malicious insiders, but also from government surveillance. This state of affairs motivates the need for users to be able to encrypt their online data.In this dissertation, we explore how to help users encrypt their online data, with a special focus on securing email. First, we explore the design principles that are necessary to create usable, secure email. As part of this exploration, …


The Quest To Secure Email: A Usability Analysis Of Key Management Alternatives, Jeffrey Thomas Andersen Jul 2016

The Quest To Secure Email: A Usability Analysis Of Key Management Alternatives, Jeffrey Thomas Andersen

Theses and Dissertations

The current state of email security is lacking, and the need for end-to-end encryption of email is clear. Recent research has begun to make progress towards usable, secure email for the masses (i.e., novice users without IT support). In this paper, we evaluate the usability implications of three different key management approaches: PGP, IBE, and passwords. Our work is the first formal A/B evaluation of the usability of different key management schemes, and the largest formal evaluation of secure email ever performed. Our results reveal interesting inherent usability trade-offs for each approach to secure email. Furthermore, our research results in …


The Asynchronous T-Step Approximation For Scheduling Batch Flow Systems, David R. Grimsman Jun 2016

The Asynchronous T-Step Approximation For Scheduling Batch Flow Systems, David R. Grimsman

Theses and Dissertations

Heap models in the max-plus algebra are interesting dynamical systems that can be used to model a variety of tetris-like systems, such as batch flow shops for manufacturing models. Each heap in the model can be identified with a single product to manufacture. The objective is to manufacture a group of products in such an order so as to minimize the total manufacturing time. Because this scheduling problem reduces to a variation of the Traveling Salesman Problem (known to be NP-complete), the optimal solution is computationally infeasible for many real-world systems. Thus, a feasible approximation method is needed. This work …


A Distributed Control Algorithm For Small Swarms In Cordon And Patrol, C Kristopher Alder Jun 2016

A Distributed Control Algorithm For Small Swarms In Cordon And Patrol, C Kristopher Alder

Theses and Dissertations

Distributed teams of air and ground robots have the potential to be very useful in a variety of application domains, and much work is being done to design distributed algorithms that produce useful behaviors. This thesis presents a set of distributed algorithms that operate under minimal human input for patrol and cordon tasks. The algorithms allow the team to surround and travel between objects of interest. Empirical analyses indicate that the surrounding behaviors are robust to variations on the shape of the object of interest, communication loss, and robot failures.


Using Perceptually Grounded Semantic Models To Autonomously Convey Meaning Through Visual Art, Derrall L. Heath Jun 2016

Using Perceptually Grounded Semantic Models To Autonomously Convey Meaning Through Visual Art, Derrall L. Heath

Theses and Dissertations

Developing advanced semantic models is important in building computational systems that can not only understand language but also convey ideas and concepts to others. Semantic models can allow a creative image-producing-agent to autonomously produce artifacts that communicate an intended meaning. This notion of communicating meaning through art is often considered a necessary part of eliciting an aesthetic experience in the viewer and can thus enhance the (perceived) creativity of the agent. Computational creativity, a subfield of artificial intelligence, deals with designing computational systems and algorithms that either automatically create original and functional products, or that augment the ability of humans …


Graphical Narrative Interfaces: Representing Spatiotemporal Information For A Human-Robot Team With A Highly Autonomous Robot, Hiroaki Nakano May 2016

Graphical Narrative Interfaces: Representing Spatiotemporal Information For A Human-Robot Team With A Highly Autonomous Robot, Hiroaki Nakano

Theses and Dissertations

Having a well-developed Graphical User Interface (GUI) is often necessary for a human-robot team, especially when the human and the robot are not in close proximity to each other or when the human does not interact with the robot in real time. Most current GUIs process and display information in real time, but the time to interact with these systems does not scale well when the complexity of the displayed information increases or when information must be fused to support decision-making. We propose a new interface concept, a Graphical Narrative Interface (GNI), which presents story-based summaries driven by accumulated data. …


Intelligent Pen: A Least Cost Search Approach To Stroke Extraction In Historical Documents, Kevin L. Bauer May 2016

Intelligent Pen: A Least Cost Search Approach To Stroke Extraction In Historical Documents, Kevin L. Bauer

Theses and Dissertations

Extracting strokes from handwriting in historical documents provides high-level features for the challenging problem of handwriting recognition. Such handwriting often contains noise, faint or incomplete strokes, strokes with gaps, overlapping ascenders and descenders and competing lines when embedded in a table or form, making it unsuitable for local line following algorithms or associated binarization schemes. We introduce Intelligent Pen for piece-wise optimal stroke extraction. Extracted strokes are stitched together to provide a complete trace of the handwriting. Intelligent Pen formulates stroke extraction as a set of piece-wise optimal paths, extracted and assembled in cost order. As such, Intelligent Pen is …


Barriers To Initiation Of Open Source Software Projects In Research Libraries, Jason Curtis Thacker May 2016

Barriers To Initiation Of Open Source Software Projects In Research Libraries, Jason Curtis Thacker

Theses and Dissertations

Libraries share a number of core values with the Open Source Software (OSS) movement, suggesting there should be a natural tendency toward library participation in OSS projects. However, Dale Askey's 2008 Code4Lib column entitled We Love Open Source Software. No, You Can't Have Our Code, claims that while libraries are strong proponents of OSS, they are unlikely to actually contribute to OSS projects. He identifies, but does not empirically substantiate, six barriers that he believes contribute to this apparent inconsistency. The goal of this thesis is to empirically investigate not only Askey's central claim but also the six barriers he …


Confirm: Clustering Of Noisy Form Images Using Robust Matching, Christopher Alan Tensmeyer May 2016

Confirm: Clustering Of Noisy Form Images Using Robust Matching, Christopher Alan Tensmeyer

Theses and Dissertations

Identifying the type of a scanned form greatly facilitates processing, including automated field segmentation and field recognition. Contrary to the majority of existing techniques, we focus on unsupervised type identification, where the set of form types are not known apriori, and on noisy collections that contain very similar document types. This work presents a novel algorithm: CONFIRM (Clustering Of Noisy Form Images using Robust Matching), which simultaneously discovers the types in a collection of forms and assigns each form to a type. CONFIRM matches type-set text and rule lines between forms to create domain specific features, which we show outperform …


An Analyzer For Message Passing Programs, Yu Huang May 2016

An Analyzer For Message Passing Programs, Yu Huang

Theses and Dissertations

Asynchronous message passing systems are fast becoming a common means for communication between devices. Two problems existing in message passing programs are difficult to solve. The first problem, intended or otherwise, is message-race where a receive may match with more than one send in the runtime system. This non-determinism often leads to intermittent and unexpected behavior depending on the resolution of the race. Another problem is deadlock, which is a situation in that each member process of the group is waiting for some member process to communicate with it, but no member is attempting to communicate with it. Detecting if …


Increment - Interactive Cluster Refinement, Logan Adam Mitchell Mar 2016

Increment - Interactive Cluster Refinement, Logan Adam Mitchell

Theses and Dissertations

We present INCREMENT, a cluster refinement algorithm which utilizes user feedback to refine clusterings. INCREMENT is capable of improving clusterings produced by arbitrary clustering algorithms. The initial clustering provided is first sub-clustered to improve query efficiency. A small set of select instances from each of these sub-clusters are presented to a user for labelling. Utilizing the user feedback, INCREMENT trains a feature embedder to map the input features to a new feature space. This space is learned such that spatial distance is inversely correlated with semantic similarity, determined from the user feedback. A final clustering is then formed in the …


Enabling Optimizations Through Demodularization, Blake Dennis Johnson Mar 2016

Enabling Optimizations Through Demodularization, Blake Dennis Johnson

Theses and Dissertations

Programmers want to write modular programs to increase maintainability and create abstractions, but modularity hampers optimizations, especially when modules are compiled separately or written in different languages. In languages with syntactic extension capabilities, each module in a program can be written in a separate language, and the module system must ensure that the modules interoperate correctly. In Racket, the module system ensures this by separating module code into phases for runtime and compile-time and allowing phased imports and exports inside modules. We present an algorithm, called demodularization, that combines all executable code from a phased modular program into a single …