Back end of line (BEOL) metal-insulator-metal capacitors (MIMCAPs) have become a core passive component in modern integrated circuits. International Technology Roadmap for Semiconductors (ITRS) projections for scaling of analog/mixed-signal MIMCAP applications require simultaneously increasing capacitance density while maintaining low leakage current density and low voltage nonlinearity (characterized by the quadratic...
Although machine learning systems are often effective in real-world applications, there are situations in which they can be even better when provided with some degree of end user feedback. This is especially true when the machine learning system needs to customize itself to the end user's preferences, such as in...
Social interactions are a ubiquitous part of our lives, and the creation of online social communities has been a natural extension of this phenomena. Free and Open Source Software (FOSS) development efforts are prime examples of how communities can be leveraged in software development, where groups are formed around communities...
Automatic event extraction from natural text is an important and challenging task for natural language understanding. Traditional event detection methods heavily rely on manually engineered rich features. Recent deep learning approaches alleviate this problem by automatic feature engineering. But such efforts, like tradition methods, have so far only focused on...
The proliferation of mobile users and internet content has advanced a plethora of research areas. Among these areas include mobile networks, transport layer protocols, and smart cities. Research shows that global mobile data traffic will increase sevenfold reaching 49 exabytes per month by 2021, most of which will be mobile...
Coverage algorithms for deployment of WiFO - a hybrid femtocell architecture based on WiFi and Free Space Optical (FSO) technologies are studied to significantly increase wireless throughput of existing WiFi networks. In contrast with existing WiFi networks, WiFO incorporates small cell size, line of sight transmissions, and the Gaussian attenuation...
With explosive growth of Internet access from smart phones and tablets, increasing bandwidth for WIFI system is badly needed. Depending on two years’ research, we produced a novel communication system called WIFO system, which integrates both RF (Radio Frequency) and FSO (Free Space Optical) techniques. WIFO system can significantly increase...
The main goal of automated test generation is to improve the reliability of a program by exposing faults to developers. To this end, testing should cover the largest possible portion of the program given a test budget (i.e., time and resources) as frequently as possible. Coverage of a program entity...
When the term renewable energy is mentioned in a conversation, wind, solar, and hydro energy typically come to mind. However, there is one major resource that has remained mostly untapped: wave energy. Wind and solar power technologies are well established around the world but they cannot generate electricity all the...
We explored an optofluidic sensing mechanism from inkjet-printed droplets on diatom biosilica using surface-enhanced Raman scattering (SERS). Our study revealed a new biosensing strategy that combines the microscopic fluidic flow induced by the droplet evaporation and the photonic crystal effects of diatom frustules, which can provide an ultra-sensitive, cost-effective biosensing...
A bad software development process leads to wasted effort and inferior products. In order to improve a software process, it must be first understood. In this work I focus on understanding software processes.
The first process we seek to understand is Continuous Integration (CI). CI systems automate the compilation, building,...
There are generally two types of multiview video:(1) 3D Multiview Video (“3D MVV” also called “2D plus delta” or “stereo” multi-view video): 3D MVV is widely deployed in cinemas and in the TV industry. 3D MVV typically entails capturing video of an object using two cameras with differing view angles...
Wireless power transfer (WPT) is a way to transfer power from one device to another without any wire or cable connections. Although the technology has been around for more than 100 years, it is gaining popularity in recent years due to the ever-increasing demand for faster and more frequent charging...
Software testing is the process of evaluating the accuracy and performance of software, and automated software testing allows programmers to develop software more efficiently by decreasing testing costs. We compared two advanced random test generators, a Feedback-Directed Random Test Generator (FDR) and a Feedback-Controlled Random Test Generator (FCR), for an...
Mutation testing is one of the effective approaches measuring test adequacy of test suites. It is widely used in both academia and industry. Unfortunately, the adoption and practical use of mutation testing for Python 2.x programs face three obstacles. First, limited useful mutation operators. Existing mutation testing tools support very...
Monte Carlo tree search (MCTS) is a class of online planning algorithms for Markov decision processes (MDPs) and related models that has found success in challenging applications. In the online planning approach, the agent makes a decision in the current state by performing a limited forward search over possible futures...
Due to a lack of grain boundaries, an amorphous metal thin film (AMTF) possesses advantageous mechanical properties and enhanced chemical stability that is potentially useful for thermal inkjet (TIJ) printing applications. The use of an AMTF as a TIJ resistor or cavitation plate could lead to a thinner TIJ cavitation...
As the CMOS process scales down to submicron, digital circuit performance improves, while reduced supply voltage and lower transistor intrinsic gain make it difficult to implement analog circuits in a power efficient manner. Therefore, it has become advantageous to shift more analog signal processing functions conventionally realized in voltage (analog)...
This thesis proposes a novel technique that exploits spectrum occupancy behaviors inherent to wideband spectrum access to enable efficient cooperative spectrum sensing. The proposed technique reduces the number of required sensing measurements while accurately recovering spectrum occupancy information. It does so by leveraging compressive sampling theory to exploit the block-like...
3D symmetric tensor fields have a wide range of applications, such as in solid and fluid mechanics, medical imaging, meteorology, molecular dynamics, geophysics and computer graphics. There has been much research carried out in this field, yet our knowledge of the tensor field is still at its initial stage to...
This thesis focuses on the problem of object tracking. Given a video, the general objective of tracking is to track the location over time of one or more targets in the image sequence. This is a very challenging task as algorithms need to deal with problems such as appearance variations,...
CoprHD is an open source software-defined storage and API platform which creates an abstraction layer over multi-vendor heterogeneous storage systems. It offers the ability to discover, pool and automate the management of the storage ecosystem with the help of storage drivers establishing connections between CoprHD and storage systems. On the...
Recent sensor System-on-Chips (SoC) have enabled significant advances in energy-efficiency by incorporating various micro-powered building blocks. Unfortunately, most of these sensor systems do not address the high power cost associated with data storage and transmission, which in some cases vastly exceeds the power consumed by the rest of the SoC....
Markov Decision Processes (MDPs) are the de-facto formalism for studying sequential decision making problems with uncertainty, ranging from classical problems such as inventory control and path planning, to more complex problems such as reservoir control under rainfall uncertainty and emergency response optimization for fire and medical emergencies. Most prior research...
Appropriate representations of variational software simplify the analysis of their properties.This thesis proposes tailored representations of two kinds variational softwares: difference files of merge commits in Git and feature models. For the former, we use the Choice Edit Model, which is based on the choice calculus, to represent changes introduced...
This work is inspired by problems in natural resource management centered on the challenge of invasive species. Computing optimal management policies for maintaining ecosystem sustainable is challenging. Many ecosystem management problems can be formulated as MDP (Markov Decision Process) planning problems. In a simulator-defined MDP, the Markovian dynamics and rewards...
Debugging, an integral part of software development, is difficult for end-user programmers, especially in the case of complex programs. The process of isolating errors is time consuming without the help of debugging support provided by the tool. For example, the visual programming tool LondonTube supports creation of custom mobile-cloud-web applications,...
It has been estimated that data traffic from the different mobile devices that range from smartphones to machine-to-machine (M2M) devices will exceed 15.9 exabyte per month by the year 2018. With this immense data growth, the current wireless communication systems suffer from the scarcity of the radio spectrum and eventually...
General-purpose Graphics Processing Units (GPGPUs) have become a critical component in high-performance computing (HPC) systems in executing modern computational workloads. The high thread level parallelism (TLP) and programmable shader cores allow thousands of threads to execute in Parallel. The fast-scaling of GPGPUs have increased the demand for performance optimizations on...
The current state of research on gossip techniques for wireless broadcasting is very limited because past research efforts have mostly focused on using gossip techniques for multicast communication. On the other hand, those research efforts that have focused on using gossip techniques for wireless broadcast communications ignore energy efficiency and...
Machine learning models for natural language processing have traditionally relied on large numbers of discrete features, built up from atomic categories such as word forms and part-of-speech labels, which are considered completely distinct from each other. Recently however, the advent of dense feature representations coupled with deep learning techniques has...
This dissertation presents a phase domain in-loop-bandwidth spread-spectrum clock generation technique. In this proposed technique, a charge-based discrete-time loop filter is proposed to enable the phase domain in-loop-bandwidth spread-spectrum modulation without a delta-sigma modulator or time-to-digital converter. The in-loop-bandwidth modulation technique maximizes the loop bandwidth to improve phase noise suppression...
Recently, there has been peaked interest in developing high energy producing and optimized power take-off topologies for Wave Energy Converters (WEC). As large as the potential of the oceans may seem, harnessing that energy and effectively converting it to electricity in significant amounts is a challenge. Currently, there are no...
Software Defined Storage is a term for data storage software to manage policy-based provisioning and management of heterogeneous data storage system abstracting underlying hardware. CoprHD is a software defined storage controller and API platform which enables policy-based management and cloud automation of storage resources for block, object and file storage...
The ability to create reproducible cryptographically secure keys from temporal environments (e.g., images) has the potential to be a contributor to effective cryptographic mechanisms. Due to the noisy nature of these environments, achieving this goal in a user friendly fashion is a very challenging task, especially since there exists a...
Recognizing human actions in videos is a long-standing problem in computer vision with a wide range of applications including video surveillance, content retrieval, and sports analysis. This thesis focuses on addressing efficiency and robustness of video classification in unconstrained real-world settings. The thesis work can be broadly divided into four...
With the development of technologies in genome sequencing and variant detection, a huge number of variants are detected. To further analyze the variants, it requires an efficient tool to annotate the functional effect of variants. This project managed to develop an efficient program to annotate the functional effect of variants...
We demonstrated a low-cost and high-sensitivity DNA detection method using quantum dot-fullerene based molecular beacons (MBs) and magnetic nanoparticles. The MB tethered magnetic nanoparticles can be well dispersed in analytes for efficient DNA capture and concentrated by an external magnetic field for enhanced fluorescence signal detection. The detection requires only...
In bioacoustics, automatic animal voice detection and recognition from audio recordings is an emerging topic for animal preservation. Our research focuses on bird bioacoustics, where the goal is to segment bird syllables from the recording and predict the bird species for the syllables. Traditional methods for this task addresses the...
Spintronics is an emerging field of research wherein the electron spin instead of, or along with, the conventional electron charge may be utilized in developing next generation logic devices. One of the most promising aspects of spintronics is that information transfer may be achieved by spin waves in logic devices,...
This dissertation focuses on the development of ultra-compact optical devices for free-space modulation. We propose a surface-normal modulator using metallic photonic crystals for free-space optical interconnects. The active control of light intensity is achieved by engineering the Fano resonances in metallic photonic crystals. Both thermo-optic modulation and electro-optic modulation of...
Software testing is a very important task during software development and it can be used to improve the quality and reliability of the software system. One potential way to reduce the cost and increase the efficiency of software testing is to generate test data automatically. Search-based approaches successfully generate unit...
Incremental ADCs (IADCs) have found wide applications in sensor interface circuitry since, compared to ∆Σ ADCs, they provide low-latency high-accuracy conversion and easy multiplexing among multiple channels. On the other hand, continuous-time ∆Σ ADCs (CTDSM) have been receiving more and more attention as a power-efficient solution in targeting medium to...
Continuous integration (CI) systems automate the compilation, building, and testing of software. Despite CI being one of the most widely used processes in software engineering, we do not know what motivates developers to use CI, and what barriers and unmet needs they face. Without such knowledge developers make easily avoidable...
Deep learning has greatly improved visual recognition in recent years. However, recent research has shown that there exist many adversarial examples that can negatively impact the performance of such an architecture. Different from previous perspectives that focus on improving the classifiers to detect the adversarial examples, this work focuses on...
To protect user’s privacy and system’s integrity, mobile platforms use permission models to control accesses to protected resources such as GPS location, Contacts, etc. The previous major version of Android used a static permission model, which compromised the security and privacy of apps. Android 6 overhauled its permission model to...
Cognitive radio technology emerges as a promising solution for overcoming shortage and inefficient use of spectrum resources. In cognitive radio networks, secondary users, which are users equipped with cognitive radios, can opportunistically access spectrum assigned to primary users, the spectrum license holders. Although it improves spectrum utilization efficiency, this opportunistic...
Massive MIMO is a promising technique for future 5G communications due to its high spectrum and energy efficiency. To realize its potential performance gain, accurate channel state information at transmitter side (CSIT) is essential. Frequency division duplex (FDD) is widely employed by the most cellular systems today. However, it requires...
In wireless communication, channel state information (CSI) is essential for data detection. Fast fading coefficients estimation is important in order to acquire accurate CSI. Kalman filters (KF) are widely used for real time parameter estimation and can be used to estimate the fast fading coefficients of a mobile communication channel....
The rapid scaling of network bandwidth and data center throughput has motivated the wide adoption of high speed transceivers. Silicon photonics (Si-Photonic) is one of the most promising techniques to realize tightly integrated optical transceivers for next-generation high speed I O standards. This dissertation focuses on the design techniques of...