Computer Engineering Commons^™

Modeling Movement Decisions In Networks: A Discrete Choice Model Approach, Larry Lin Junjie

Dissertations and Theses Collection (Open Access)

In this dissertation, we address the subject of modeling and simulation of agents and their movement decision in a network environment. We emphasize the development of high quality agent-based simulation models as a prerequisite before utilization of the model as an evaluation tool for various recommender systems and policies. To achieve this, we propose a methodological framework for development of agent-based models, combining approaches such as discrete choice models and data-driven modeling.

The discrete choice model is widely used in the field of transportation, with a distinct utility function (e.g., demand or revenue-driven). Through discrete choice models, the movement decision …

Logging, Visualization, And Analysis Of Network And Power Data Of Iot Devices, Neal Huynh Nguyen

Master's Theses

There are approximately 23.14 billion IoT(Internet of Things) devices currently in use worldwide. This number is projected to grow to over 75 billion by 2025. Despite their ubiquity little is known about the security and privacy implications of IoT devices. Several large-scale attacks against IoT devices have already been recorded.

To help address this knowledge gap, we have collected a year’s worth of network traffic and power data from 16 common IoT devices. From this data, we show that we can identify different smart speakers, like the Echo Dot, from analyzing one minute of power data on a shared power …

A Framework For Characterizing The Security Posture Of Cyber Systems, Matthew Ridley

Theses and Dissertations

Modern day applications can be spread across multiple virtual or physical systems, and be accessed or attacked by pretty much any one any where. Cybersecurity is used to mitigate these cyber threats but there are limited resources that can be dedicated to security. As result, trade-offs and decisions must be made around what is prioritized and what isn’t. Cyber risk management provides methodologies for identifying threats, evaluating risks and making decisions, however, it can be difficult to determine whether the system is actually secure enough and the risk is actually within an acceptable parameters. This thesis provides a framework for …

Teen Driver System Modeling: A Tool For Policy Analysis, Celestin Missikpode, Corrine Peek-Asa, Daniel V. Mcgehee, James Torner, Wayne Wakeland, Robert Wallace

Complex Systems Faculty Publications and Presentations

Background: Motor vehicle crashes remain the leading cause of teen deaths in spite of preventive efforts. Prevention strategies could be advanced through new analytic approaches that allow us to better conceptualize the complex processes underlying teen crash risk. This may help policymakers design appropriate interventions and evaluate their impacts.

Methods: System Dynamics methodology was used as a new way of representing factors involved in the underlying process of teen crash risk. Systems dynamics modeling is relatively new to public health analytics and is a promising tool to examine relative influence of multiple interacting factors in predicting a health …

Autonomous Collision Avoidance In Small Scale Vehicles, Justin T. Sharpe

Honors Theses

The undergraduate research performed in this study focused on autonomous collision avoidance in small scale vehicles. The goal of this study was to find equipment to build a fully autonomous small scale vehicle for use in different applications. Radio frequency communication, ultrasonic sensors, and single board computers were used to create an autonomous vehicle for multiple applications. Different communication protocols and sensors were investigated, and an explanation was specified concerning the hardware choice. The main communication protocol tested was Long Range Wide Area Network, and the main electronics tested and used were ultrasonic sensors, First Person View cameras, and the …

Empathetic Computing For Inclusive Application Design, Kenny Choo Tsu Wei

Dissertations and Theses Collection (Open Access)

The explosive growth of the ecosystem of personal and ambient computing de- vices coupled with the proliferation of high-speed connectivity has enabled ex- tremely powerful and varied mobile computing applications that are used every- where. While such applications have tremendous potential to improve the lives of impaired users, most mobile applications have impoverished designs to be inclusive– lacking support for users with specific disabilities. Mobile app designers today haveinadequate support to design existing classes of apps to support users with specific disabilities, and more so, lack the support to design apps that specifically target these users. One way to resolve …

Automatically `Verifying’ Discrete-Time Complex Systems Through Learning, Abstraction And Refinement, Jingyi Wang, Jun Sun, Shengchao Qin, Cyrille Jegourel

Research Collection School Of Computing and Information Systems

Precisely modeling complex systems like cyber-physical systems is challenging, which often render model-based system verification techniques like model checking infeasible. To overcome this challenge, we propose a method called LAR to automatically ‘verify’ such complex systems through a combination of learning, abstraction and refinement from a set of system log traces. We assume that log traces and sampling frequency are adequate to capture ‘enough’ behaviour of the system. Given a safety property and the concrete system log traces as input, LAR automatically learns and refines system models, and produces two kinds of outputs. One is a counterexample with a bounded …

Co-Location Resistant Virtual Machine Placement In Cloud Data Centers, Amit Agarwal, Nguyen Binh Duong Ta

Research Collection School Of Computing and Information Systems

Due to increasing number of avenues for conducting cross-virtual machine (VM) side-channel attacks, the security of public IaaS cloud data centers is a growing concern. These attacks allow an adversary to steal private information from a target user whose VM instance is co-located with that of the adversary. To reduce the probability of malicious co-location, we propose a novel VM placement algorithm called “Previously Co-Located Users First”. We perform a theoretical and empirical analysis of our proposed algorithm to evaluate its resource efficiency and security. Our results, obtained using real-world cloud traces containing millions of VM requests and thousands of …

Early Prediction Of Merged Code Changes To Prioritize Reviewing Tasks, Yuanrui Fan, Xin Xia, David Lo, Shanping Li

Research Collection School Of Computing and Information Systems

Modern Code Review (MCR) has been widely used by open source and proprietary software projects. Inspecting code changes consumes reviewers much time and effort since they need to comprehend patches, and many reviewers are often assigned to review many code changes. Note that a code change might be eventually abandoned, which causes waste of time and effort. Thus, a tool that predicts early on whether a code change will be merged can help developers prioritize changes to inspect, accomplish more things given tight schedule, and not waste reviewing effort on low quality changes. In this paper, motivated by the above …

Mitigating Loss Of Control In General Aviation: A Human-Systems Integrated Flight Test Method For Mapping Pilot Cognition And Aircraft Dynamics, Tiziano Bernard

Theses and Dissertations

General aviation (GA) loss of control accidents, in the United States, have continued to occur despite efforts by government and non-government research agencies. The lack of data during loss of control events (due to the absence of data recorders in small aircraft) does not allow for an accurate reconstruction of the accidents, causing accident investigators to focus on generic causes like pilot error. Flight test research has shown that there are various systems induced causal factors that can potentially set up an aircraft to depart controlled flight and do not aid pilot efforts. An example of these causal factors is …

Mindful: A Novel Virtual System Migration Decision-Making Framework For Automated Cyber-Resiliency, Nicholas James Lowing

Theses and Dissertations

Virtual system migration has revolutionized modern computing. As an advantageous byproduct of virtualization, virtual system migration has allowed for cheaper, more robust cloud management. The selection of a destination host during migration is a key component of migration management. However, there is currently no state-of-the-art, standardized framework for making this decision. Previous work related to automated load balancing is plentiful, but when load balancing is not the primary focus of the cloud management strategy there is a lack of research. We focus on this case, where virtual systems are no longer moved based on some predefined optimization pattern, but rather …

Modeling And Simulation Methodologies For Spinal Cord Stimulation., Saliya Kumara Kirigeeganage

Electronic Theses and Dissertations

The use of neural prostheses to improve health of paraplegics has been a prime interest of neuroscientists over the last few decades. Scientists have performed experiments with spinal cord stimulation (SCS) to enable voluntary motor function of paralyzed patients. However, the experimentation on the human spinal cord is not a trivial task. Therefore, modeling and simulation techniques play a significant role in understanding the underlying concepts and mechanics of the spinal cord stimulation. In this work, simulation and modeling techniques related to spinal cord stimulation were investigated. The initial work was intended to visualize the electric field distribution patterns in …

Automatic Performance Optimization On Heterogeneous Computer Systems Using Manycore Coprocessors, Chenggang Lai

Graduate Theses and Dissertations

Emerging computer architectures and advanced computing technologies, such as Intel’s Many Integrated Core (MIC) Architecture and graphics processing units (GPU), provide a promising solution to employ parallelism for achieving high performance, scalability and low power consumption. As a result, accelerators have become a crucial part in developing supercomputers. Accelerators usually equip with different types of cores and memory. It will compel application developers to reach challenging performance goals. The added complexity has led to the development of task-based runtime systems, which allow complex computations to be expressed as task graphs, and rely on scheduling algorithms to perform load balancing between …

An Rs-485 Transceiver In A Silicon Carbide Cmos Process, Maria Raquel Benavides Herrera

Graduate Theses and Dissertations

This thesis presents the design, simulation and test results of a silicon carbide (SiC) RS-485 transceiver for high temperature applications. This circuit is a building block in the design and fabrication of a digital data processing and control system. Automation processes for extreme environments, remote connection to high temperature locations, deep earth drilling, and high temperature data acquisition are some of the potential applications for such a system. The transceiver was designed and developed in a 1.2 µm SiC-CMOS process by Raytheon Systems, Ltd. (UK). It has been tested with a supply voltage of 12 V and 15 V, temperatures …

Smart Surge Irrigation Using Microcontroller Based Embedded Systems And Internet Of Things, Prashant Dinkar Borhade

Graduate Theses and Dissertations

Surge Irrigation is a type of furrow irrigation and one of many efficient irrigation techniques. It is one of the economical techniques and requires minimum labor for monitoring it. In surge irrigation, water is applied intermittently to a field to achieve uniform distribution of water along the furrows, which is important while irrigating, as it ensures that there is enough water near the root zone of the crop. The uneven distribution can cause a loss in crop productivity.

Surge irrigation uses a surge valve, which is an electro-mechanical device that irrigates a field. The commercial surge valves available on the …

Design And Analysis Of Binary Driven Coherent M-Ary Qam Transmitter For Next Generation Optical Networks, Naji Albakay

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

This work presents a design for a binary driven optical square M-ary quadrature amplitude modulation (QAM) transmitter for high speed optical networks. The transmitter applies tandem quadrature phase shift keying (QPSK) modulators to eliminate the need for linear broadband amplifiers and high-resolution digital to analog converters (DACs), which are both required by conventional transmitters. The transmitter design could be scaled to any order of square M-ary QAM by simply adding more QPSK modulators in tandem. It also provides a Gray coded symbol constellation, insuring the lowest bit error rate possible during symbol recovery. We also provide the design for the …

Building A Smart Nation: Singapore's Digital Journey, Siu Loon Hoe

Research Collection School Of Computing and Information Systems

Singapore’s smart nation journey began when the drive was officially announced by the country’s Prime Minister Lee Hsien Loong in November 2014 (Lee, 2014). The vision is to improve people’s lives and create more opportunities through information and communications technology (ICT). The smart nation drive is an effort by the government to co-create innovative, people-centric solutions with citizens and businesses. The three priority areas, underpinned by cyber security, are elderly, transportation and data. Since then, various digital strategies and policies have been further articulated, and digital programmes and projects implemented in the country.

Deep Unsupervised Pixelization, Chu Han, Qiang Wen, Shengfeng He, Qianshu Zhu, Yinjie Tan, Guoqiang Han, Tien-Tsin Wong

Research Collection School Of Computing and Information Systems

In this paper, we present a novel unsupervised learning method for pixelization. Due to the difficulty in creating pixel art, preparing the paired training data for supervised learning is impractical. Instead, we propose an unsupervised learning framework to circumvent such difficulty. We leverage the dual nature of the pixelization and depixelization, and model these two tasks in the same network in a bi-directional manner with the input itself as training supervision. These two tasks are modeled as a cascaded network which consists of three stages for different purposes. GridNet transfers the input image into multi-scale grid-structured images with different aliasing …

Evoalloy: An Evolutionary Approach For Analyzing Alloy Specifications, Jianghao Wang

School of Computing: Dissertations, Theses, and Student Research

Using mathematical notations and logical reasoning, formal methods precisely define a program’s specifications, from which we can instantiate valid instances of a system. With these techniques, we can perform a variety of analysis tasks to verify system dependability and rigorously prove the correctness of system properties. While there exist well-designed automated verification tools including ones considered lightweight, they still lack a strong adoption in practice. The essence of the problem is that when applied to large real world applications, they are not scalable and applicable due to the expense of thorough verification process. In this thesis, I present a new …

Controller Evolution And Divergence: A Software Perspective, Balaji Balasubramaniam

School of Computing: Dissertations, Theses, and Student Research

Successful controllers evolve as they are refined, extended, and adapted to new systems and contexts. This evolution occurs in the controller design and also in its software implementation. Model-based design and controller synthesis can help to synchronize this evolution of design and software, but such synchronization is rarely complete as software tends to also evolve in response to elements rarely present in a control model, leading to mismatches between the control design and the software.

In this thesis, we perform a first-of-its-kind study on the evolution of two popular open-source safety-critical autopilot control software -- ArduPilot, and Paparazzi, to better …