Recently, delta-sigma modulation has become a widely applied technique for high-performance analog-to-digital conversion of narrow-band signals. Most of the early designs used discrete-time structure for good accuracy and good linearity. The transfer functions are independent of the clock frequency. However, high unity-gain bandwidths of the opamps are required to satisfy...
Harvesting energy from the environment for powering micro-power devices have been increasing in popularity. These types of devices can be used in embedded applications or in sensor networks where battery replacement is impractical. In this dissertation, different methods of energy harvesting from the environment are explored as alternative sources of...
Forward Error Correction and retransmission are two approaches used to reliably broadcast data in a network with poor quality of service. Taking some assumptions, it has been suggested that a retransmission based reliable broadcasting scheme using network coding should in theory provide an increase in bandwidth efficiency by combining packets...
An automated method, requiring the fabrication of a small set of test structures, efficiently extracts the coefficients of Z-parameter based macromodels. The extraction approach has been validated for both heavily and lightly doped substrates and can be applied to a variety of technologies. After the parameters of a macromodel have...
Web applications are popular attack targets. Misuse detection systems use signature databases to detect known attacks. However, it is difficult to keep the database up to date with the rate of discovery of vulnerabilities. They also cannot detect zero-day attacks. By contrast, anomaly detection systems learn the normal behavior of...
Although the digital revolution can realize many of past analog components in the digital forms, our world is surrounded with analog signals such as voice, temperature, etc. The bridge between these two worlds is one of key performance limitations among overall systems and it includes analog filters and data converters....
Active participation and collaboration of community members are crucial to the continuation and expansion of open source software projects. Researchers have recognized the value of community in open source development and studied various aspects of it including structure of communities, motivations for participation, and collaboration among members. However, the majority...
The world’s energy consumption is growing at an alarming rate and the need for renewable energy is apparent now more than ever. Estimates have shown that optimization of the extraction of energy from the ocean could significantly aid the world’s quest for sustainable and affordable energy services for all. From...
Building intelligent computer assistants has been a long-cherished goal of AI. Many intelligent assistant systems were built and fine-tuned to specific application domains. In this work, we develop a general model of assistance that combines three powerful ideas: decision theory, hierarchical task models and probabilistic relational languages. We use the...
Analog-to-Digital Data Converters (ADCs) used in instrumentation and measurements often require high absolute accuracy, including excellent linearity and negligible dc offset. Incremental data converters (IDCs) provide a solution for such measurement applications. Since IDCs are essentially delta-sigma converters with reset operation before each conversion, they retain most of the advantages...
Multiple-input multiple-output (MIMO) communication systems have recently been considered as one of the most significant technology breakthroughs for modern wireless communications, due to the higher spectral efficiency and improved link reliability. The sphere decoding algorithm (SDA) has been widely used for maximum likelihood (ML) detection in MIMO systems. It is...
The purpose of this thesis is to explore methods which can reduce the power dissipation of a mobile system while decoding MPEG video. MPEG decoding is a microprocessor intensive process that makes heavy use of both the L1 and L2 caches as well as main memory. The heavy load placed...
There has been little prior research reporting strategy usage in end-user problem solving, and even less using gender as a factor. Without this type of information, enduser programming systems cannot know the “target” at which to aim, if they are to support male and female end-user programmers’ debugging. As a...
The problem of locating a signal source, or an emitter, has many civilian and military applications, such as communication regulations enforcement, military reconnaissance, and search-and-rescue operations. Many of the most widely used emitter location methods rely on the accurate and robust estimation of the differential time delay,
or time-difference-of-arrival (TDOA),...
Protecting end-users privacy and building trust are the two most important factors needed to support the growth of ecommerce. The increased dependence on the Internet for a wide variety of daily transactions causes a corresponding loss in privacy for many users, as virtually all websites collect data from users directly...
Remote sensors are becoming the standard for observing and recording ecological data in the field. Such sensors can record data at fine temporal resolutions, and they can operate under extreme conditions prohibitive to human access. Unfortunately, sensor data streams exhibit many kinds of errors ranging from corrupt communications to partial...
A significantly untapped renewable energy source exists in the world's oceans. It is estimated that if 0.2% of the ocean's untapped energy could be harnessed, it could provide power sufficient for the entire world. Ocean energy extraction is an old concept, and it is currently seeing the benefit of advancing...
The primary objective of this thesis is to explore new absorber and p-type window layer materials for thin-film solar cell applications. A new thin-film electron beam deposition system has been installed, is now operational, and has been used to deposit several types of solar cell absorber layers. Material investigations include...
The world's oceans contain tremendous renewable energy potentials. It is estimated that if 0.2% of the ocean's untapped energy could be harnessed, it could provide power sufficient for the entire world [1]. This thesis provides a comprehensive description of the state-of-the-art of ocean energy extraction technologies and lessons learned from...
Systems biology is becoming increasingly important for the study of living organisms. It focuses on the mathematical understanding of biological systems. Cells, the basic units of all living creatures, are biological systems of major interest. Considerable work is being done towards modeling cells as mathematical systems. At the same time,...
