Engineering Commons^™

Reasoning Across Language And Vision In Machines And Humans, Andrei Barbu

Open Access Dissertations

Humans not only outperform AI and computer-vision systems, but use an unknown computational mechanism to perform tasks for which no suitable approaches exist. I present work investigating both novel tasks and how humans approach them in the context of computer vision and linguistics. I demonstrate a system which, like children, acquires high-level linguistic knowledge about the world. Robots learn to play physically-instantiated board games and use that knowledge to engage in physical play. To further integrate language and vision I develop an approach which produces rich sentential descriptions of events depicted in videos. I then show how to simultaneously detect …

Improving Multicore Resource Efficiency And Performance, Syed Ali Raza Jafri

Open Access Dissertations

With clock speeds stagnating for the last few years and multi-cores having replaced uniprocessors, software development must now turn towards shared memory parallel programming to continue enhancing performance. Shared memory parallel programming; however is significantly more challenging than its sequential counterpart. Conventional shared memory parallel programs can fall victim to deadlocks, livelocks and data races which are hard to detect and debug. Aside from programming complexity chipmultiprocessors need a scalable, low latency, high bandwidth interconnect fabric to deliver performance. Conventional interconnects such as crossbars and buses can deliver low latency but do not scale with increasing number of cores. Researchers …

Automatically Optimizing Tree Traversal Algorithms, Youngjoon Jo

Open Access Dissertations

Many domains in computer science, from data-mining to graphics to computational astrophysics, focus heavily on irregular applications. In contrast to regular applications, which operate over dense matrices and arrays, irregular programs manipulate and traverse complex data structures like trees and graphs. As irregular applications operate on ever larger datasets, their performance suffers from poor locality and parallelism. Programmers are burdened with the arduous task of manually tuning such applications for better performance. Generally applicable techniques to optimize irregular applications are highly desired, yet scarce.

In this dissertation, we argue that, for an important subset of irregular programs which arises in …

Resource-Aware Distributed Particle Filtering For Cluster-Based Object Tracking In Wireless Camera Networks, Kihyun Hong

Open Access Dissertations

The proliferation of miniaturized low-power computing devices, advances in wireless communications, and the availability of inexpensive imaging sensors have enabled the development of wireless camera networks (WCN). In this dissertation, we consider the problem of real-time object tracking with a WCN. Existing object tracking methods designed for multi-camera systems do not take into account the unique constraints of WCNs. Specifically, an effective object tracking system for WCNs must anticipate unreliable network communication, limited memory, and limited computational power in each camera node. In particular, unreliable communication degrades the quality of the visual information shared by the cameras, which ultimately degrades …

Source Code Retrieval From Large Software Libraries For Automatic Bug Localization, Bunyamin Sisman

Open Access Dissertations

This dissertation advances the state-of-the-art in information retrieval (IR) based approaches to automatic bug localization in software. In an IR-based approach, one first creates a search engine using a probabilistic or a deterministic model for the files in a software library. Subsequently, a bug report is treated as a query to the search engine for retrieving the files relevant to the bug. With regard to the new work presented, we first demonstrate the importance of taking version histories of the files into account for achieving significant improvements in the precision with which the files related to a bug are located. …

Transition Faults And Transition Path Delay Faults: Test Generation, Path Selection, And Built-In Generation Of Functional Broadside Tests, Bo Yao

Open Access Dissertations

As the clock frequency and complexity of digital integrated circuits increase rapidly, delay testing is indispensable to guarantee the correct timing behavior of the circuits. In this dissertation, we describe methods developed for three aspects of delay testing in scan-based circuits: test generation, path selection and built-in test generation.

We first describe a deterministic broadside test generation procedure for a path delay fault model named the transition path delay fault model, which captures both large and small delay defects. Under this fault model, a path delay fault is detected only if all the individual transition faults along the path are …

Predictive Duty Cycling Of Radios And Cameras Using Augmented Sensing In Wireless Camera Networks, Joonhwa Shin

Open Access Dissertations

Energy efficiency dominates practically every aspect of the design of wireless camera networks (WCNs), and duty cycling of radios and cameras is an important tool for achieving high energy efficiencies. However, duty cycling in WCNs is made complex by the camera nodes having to anticipate the arrival of the objects in their field-of-view. What adds to this complexity is the fact that radio duty cycling and camera duty cycling are tightly coupled notions in WCNs.

Abstract In this dissertation, we present a predictive framework to provide camera nodes with an ability to anticipate the arrival of an object in the …

Ant: A Framework For Increasing The Efficiency Of Sequential Debugging Techniques With Parallel Programs, Jae-Woo Lee

Open Access Dissertations

Bugs in sequential programs cost the software industry billions of dollars in lost productivity each year. Even if simple parallel programming models are created, they will not reduce the level of sequential bugs in programs below that of sequential programs. It can be argued that the complexity of current parallel programming models may increase the number of sequential bugs in parallel programs because they distract the programmer from the core logic of the program.

Tools exist that identify statements related to sequential bugs and allow those bugs to be more quickly located and fixed. Their use in parallel programs will …

Mitigating The Cost, Performance, And Power Overheads Induced By Load Variations In Multicore Cloud Servers, Yu-Ju Hong

Open Access Dissertations

Load variations whether in space or time pose a significant challenge to system designers. These load variations may induce inefficiencies such as load imbalance and over-provisioning, resulting in performance/power/cost overheads. The goal of my research is to mitigate such variation-induced overheads in multicore cloud servers.

First, I focus on power/performance overheads in on-chip networks of a multicore chip. We design an on-chip network that is robust in both performance and energy across applications for time- and space-varying loads. Existing flow control mechanisms that perform well at high (low) loads suffer power and/or energy overheads at low (high) loads. In contrast, …

Hypothesize-And-Verify Based Solutions For Place Recognition And Mobile Robot Self-Localization In Interior Hallways, Khalil Mustafa Ahmad Yousef

Open Access Dissertations

There is much research interest currently in having mobile robots build accurate and visually dense models ofinterior space as they traverse through such spaces. One of the interesting problems that has came out of this research is that of visual place recognition and self-localization. This is the problem that forms the focus of the present dissertation. We show how dense and accurate 3D models of the interior space can be constructed using a hierarchical sensor-fusion architecture. Our system fuses images from a single photometric camera with range data from a laser scanning sensor. The range data used is rudimentary--the range …

Enhanced Diagnostic Accuracy Of Mammograms On A Mobile Device, Sharanya Padmanabhan

Open Access Theses

With the death of a woman every 13 minutes in the US, and one every minute worldwide, due to breast cancer, the need for early detection cannot be overstated. Mammography is a boon for both early detection and screening of breast tumors. It is an imaging system that uses low dose (9mrem) x-rays for examining the breasts, by the electrons reflected from the tissues (thermoelectric effect). However, there are 20% false positives and 10% false negatives in current practice. Hence, there is a critical need for enhancing the accuracy of these mammograms. Towards this, this thesis was aimed at enhancing …

Combining Multiple, Inexpensive Gps Receivers To Increase Accuracy And Reliability, Daniel Kenneth Schrader

Open Access Theses

GPS is a technology that allows for accurate tracking of various parameters, namely speed and location. Many modern systems and tools require a rapidly-refreshing report of their speed and/or location, but the GPS technology available to most users may not be accurate enough for some applications. Methods currently

exist to improve GPS accuracy, but many or all of these methods are expensive, difficult, or simply not available without special technology and permission.

The research presented in this thesis describes an attempt to improve the accuracy and/or reliability of GPS, without using any expensive or restricted methods. The ability for any …

Statistical And Visual Analysis Of Spatio-Temporal Dynamics Of Dengue Fever Epidemic, Amana Arshad

Open Access Theses

Public health-care data possess spatio-temporal features and it evolves with time. For example, patient count visiting an ER in a hospital evolves with time. Clustering of such input data patterns into different groups over a certain temporal duration is useful for the purpose of health-care surveillance purpose. The objective of this study is to visualize and analyze these data patterns to get an insight into data characteristics for the purpose of the health-surveillance and to correlate these findings with the possible reasons for epidemic spread. The dynamics of this spatio-temporal pattern analysis is useful for epidemic spread surveillance in large …

Analysis Of An Actuated Two Segment Leg Model Of Locomotion, Nikhil Vinayak Rao

Open Access Theses

Research studies on dynamic models of legged locomotion have generally focused on telescoping-type leg models. Such telescoping spring loaded inverted pendulum (SLIP) models have been able to accurately predict observed center of mass (CoM) trajectories. There have been comparatively fewer studies on dynamics of locomotion

with segmented legs. Some earlier studies on the dynamics due to leg segmentation appear straightforward. For example, a simple model with the only joint moment being due to a passive springy knee has been shown to behave similarly to a telescoping spring-mass model. However, in real-life animal locomotion, there are multiple joint-moments acting at the …

Adaptive Nonlinear Control For Autonomous Ground Vehicles, William Spencer Black

Open Access Theses

We present the background and motivation for ground vehicle autonomy, and focus on uses for space-exploration. Using a simple design example of an autonomous ground vehicle we derive the equations of motion. After providing the mathematical background for nonlinear systems and control we present two common methods for exactly linearizing nonlinear systems, feedback linearization and backstepping. We use these in combination with three adaptive control methods: model reference adaptive control, adaptive sliding mode control, and extremum-seeking model reference adaptive control. We show the performances of each combination through several simulation results. We then consider disturbances in the system, and design …

Interactive Multivariate Data Exploration For Risk-Based Decision Making, Silvia Oliveros Torres

Open Access Theses

Risk-based decision making is a data-driven process used to gather data about outcomes, analyze different scenarios, and deliver informed decisions to mitigate risk.

An interactive visual analytics system can help derive insights from large amounts of data and facilitate the risk management process thereby providing a suitable solution to examine different decision factors. This work introduces two separate systems that

incorporate visual analytics techniques to help the users in the tasks of identifying patterns, finding correlations, designing mitigation strategies, and assisting in the long term planning and assessment process. The first system looks at the National Health

and Nutrition Examination …

Design Of A Running Robot And The Effects Of Foot Placement In The Transverse Plane, Timothy James Sullivan

Open Access Theses

The purpose of this thesis is to make advances in the design of humanoid bipedal running robots. We focus on achieving dynamic running locomotion because it is one metric by which we can measure how far robotic technologies have advanced, in relation to existing benchmarks set by humans and other animals. Designing a running human-inspired robot is challenging because human bodies are exceptionally complex mechanisms to mimic. There are only a few humanoid robots designed specifically for running and the existing robots are either constrained to a plane, do not yet exhibit human-like motion, or are unstable.

One aspect of …