As one solution, designers are moving to higher level of abstraction or System Level design which covers both Hardware (HW) and Software (SW). This is realized through a model based design methodology which utilizes virtual environment for early validation of the specification and at... ]]> Akash Agarwal http://iris.lib.neu.edu/elec_comp_theses/105 http://iris.lib.neu.edu/elec_comp_theses/105 Tue, 16 Apr 2013 10:04:26 PDT Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to increase reliability, efficiency and safety in PV systems. Conventional fault protection methods usually add fuses or circuit breakers in series with PV components. But these protection devices are only able to clear faults and isolate faulty circuits if they carry a large fault current. However, this research shows that faults in PV arrays may not be cleared by fuses under some fault scenarios, due to the current-limiting nature and non-linear output characteristics of PV arrays.

First, this thesis introduces new simulation and analytic models that are suitable for... ]]> Ye Zhao http://iris.lib.neu.edu/elec_comp_theses/104 http://iris.lib.neu.edu/elec_comp_theses/104 Thu, 11 Apr 2013 07:21:55 PDT The design and analysis of a monolithic quad-ferential amplifier is presented. A quad-ferential amplifier consists of four inputs, four outputs, and a V_ocm pin which controls the output common-mode voltage. It is similar to a differential amplifier in that it amplifies differences and rejects overall input common-mode. An overview of a quad-ferential amplifier is offered which includes a symbol, a description of each pin, a block diagram and a brief circuit level discussion. The transfer function derivation demonstrates that symmetry of feedback and gain resistors is required for the quad-ferential amplifier to approach its ideal behavior.

The core of a... ]]> Tina Rookmaaker http://iris.lib.neu.edu/elec_comp_theses/103 http://iris.lib.neu.edu/elec_comp_theses/103 Wed, 10 Apr 2013 09:17:31 PDT This document proposes a design approach to a Parametric Measurement Unit (PMU) as well as integration of the PMU onto the same Integrated Circuit (IC) as a 600MHz Driver, Comparator, and Active Load (DCL). These circuits are necessary components of many Automated Test Equipment (ATE) systems used to test ICs and are often referred to collectively as the Pin Electronics (PE). While PMUs have been used in test systems for many years, to the author's knowledge a design approach to such circuits has yet to be published. PMUs are high accuracy low bandwidth circuits that have to drive a range... ]]> Edward Lawrence Collins http://iris.lib.neu.edu/elec_comp_theses/102 http://iris.lib.neu.edu/elec_comp_theses/102 Wed, 10 Apr 2013 07:27:49 PDT The classical sampling theory is based on Shannon-Nyquist theorem: the sampling rate must be at least twice higher than the maximum frequency in the signal. Recently a new sampling theory called compressive sensing asserts that in some cases the sampled signal can be well recovered far below the Nyquist rate. This applies to signals that are sparse in a given basis. Compressive sensing can be applied in many areas, such as signal precessing, imaging, earth probing, radar, and holography. In this thesis we introduce the basic concepts of compressive sensing and its application in coherent imaging and antenna synthesis. In... ]]> Hongyi Zhang http://iris.lib.neu.edu/elec_comp_theses/101 http://iris.lib.neu.edu/elec_comp_theses/101 Tue, 09 Apr 2013 13:29:33 PDT Most discussions of the structure and associated properties of nanotubes refer to isolated (unsupported) nanotubes. Supported nanotubes, however, should interact strongly with the substrate, and as a result a number of deformations may arise. Experimental studies, however, are mostly performed using nanotubes that are dispersed on a substrate or on nanotubes grown over lithographically defined trenches where they interact with the underlying surfaces. It is important to quantify these interactions for a variety of potential applications of nanotechnology. One such example is a CNT based nanoswitch consisting of a CNT bridging over a trench. Actuation of the CNT causes it... ]]> Mithun Chandrasekar http://iris.lib.neu.edu/elec_comp_theses/100 http://iris.lib.neu.edu/elec_comp_theses/100 Fri, 29 Mar 2013 12:28:37 PDT Remote sensing of chemical vapors with hyperspectral imaging devices plays an important part in many civilian and military applications. The EPA uses hyperspectral imaging to monitor the chemical vapor output from smoke stacks while the military uses it for detection of chemical warfare agents (CWAs) in the battleeld. Detection algorithms have been studied for decades now but a major limitation thus far has been the library of signatures available. In previous years, the signature libraries have been of very good quality but because of the effort needed per signature, only a handful of chemical plume signatures were available. On the... ]]> Andrew Lai http://iris.lib.neu.edu/elec_comp_theses/99 http://iris.lib.neu.edu/elec_comp_theses/99 Fri, 29 Mar 2013 08:10:36 PDT Modulo 2ⁿ+1 squarer is widely used in the digital system, such as digital signal processing (DSP), cryptography and residue arithmetic as an important component. In this thesis, an improved high-speed low-power design of modulo 2ⁿ+1 squarer is proposed. The primary improvement comes from algorithm, circuit implementation and implementation technology. For the algorithm, the partial product matrix reconstruction is optimized to achieve a larger range of input and fewer operation steps. Modified Wallace tree is also employed in partial product compression process. For the circuit implementation, full adders in traditional Wallace tree structure are replaced by the 3:2 compressors and a... ]]> Weifu Li http://iris.lib.neu.edu/elec_comp_theses/98 http://iris.lib.neu.edu/elec_comp_theses/98 Thu, 14 Mar 2013 08:36:16 PDT Dynamic information flow tracking is a well-known dynamic software analysis technique with a wide variety of applications that range from making systems more secure, to helping developers and analysts better understand the code that systems are executing. Traditionally, the fine-grained analysis capabilities that are desired for the class of these systems which operate at the binary level require that these analyses are tightly coupled to a specific ISA. This fact places a heavy burden on developers of these systems since significant domain knowledge is required to support each ISA, and our ability to amortize the effort expended on one ISA... ]]> Ryan James Whelan http://iris.lib.neu.edu/elec_comp_theses/97 http://iris.lib.neu.edu/elec_comp_theses/97 Fri, 08 Mar 2013 11:06:35 PST Graphics processing units (GPUs) have become widely accepted as the computing platform of choice in many high performance computing domains, due to the potential for approaching or exceeding the performance of a large cluster of CPUs for many parallel applications. The availability of programming standards such as OpenCL makes the use of GPUs even more popular to leverage the inherent parallelism offered by them. However, given the power consumption of GPUs, some devices can exhaust power budgets quickly. Better solutions are needed to effectively exploit the power-efficiency available on heterogeneous systems.

In this work, we evaluate the power-performance trade-offs of... ]]> Yash Sanjeev Ukidave http://iris.lib.neu.edu/elec_comp_theses/96 http://iris.lib.neu.edu/elec_comp_theses/96 Thu, 07 Mar 2013 08:54:41 PST Detecting subpixel objects is a difficult but core problem in hyperspectral imagery (HSI). This is accomplished by using a detection algorithm with the object's signature on each pixel in a scene. However, the effectiveness of a detector for a subpixel object depends on the background and the fraction of the pixel inhabited by the object (fill fraction). In this work, two spectral detectors are considered: the matched filter, and t-detector (cosine). A technique, relying on characteristic function inversion, is developed for computing the probability of detection and probability of false alarm for each detector under a multivariate normal (MVN) model... ]]> Eric Olsson Truslow http://iris.lib.neu.edu/elec_comp_theses/95 http://iris.lib.neu.edu/elec_comp_theses/95 Thu, 07 Mar 2013 08:06:43 PST The ability of the Phasor Measurement Unit (PMU) to directly measure the system state, has led to steady increase in the use of PMU in the past decade. However, in spite of its high accuracy and the ability to measure the states directly, they cannot completely replace the conventional measurement units due to high cost. Hence it is necessary for the modern estimators to use both conventional and phasor measurements together.

This thesis presents an alternative method to incorporate the new PMU measurements into the existing state estimator in a systematic manner such that no major modification is necessary to... ]]> Aditya Tarali http://iris.lib.neu.edu/elec_comp_theses/94 http://iris.lib.neu.edu/elec_comp_theses/94 Fri, 01 Mar 2013 10:26:37 PST This thesis describes a novel, innovative high power density electromagnetic energy harvester device powered by rotational motion. The primary aim of the thesis was to develop high power density energy scavenging device extracting power from rotational motion. In this thesis, a novel permanent magnet array based energy harvesting device is developed and a charging circuit was prototyped to extract the power generated by energy harvester and deliver it to battery. The design of the rotational energy harvester improves the performance, and the use of the axial flux permanent magnets enables inducing strong magnetic field in the coil, which resulted in... ]]> Sumeet Mohan Patil http://iris.lib.neu.edu/elec_comp_theses/93 http://iris.lib.neu.edu/elec_comp_theses/93 Thu, 28 Feb 2013 13:08:23 PST The objective of this research is to propose a novel circuit design that enables wireless energy harvesting, which is a new paradigm that scavenges energy from radio frequency (RF) electromagnetic radiation. Compared to other commonly observed alternative energy sources, such as solar and wind, RF harvesting can provide continuous supply of energy, and is not completely impaired by bad weather conditions and indoor use. However, obtaining a usable yield from this energy source is challenging as the amplitude of the arriving signals is considerably low, and the requirements for operating a commercially available sensor mote are proportionally high. The existing... ]]> Ufuk Muncuk http://iris.lib.neu.edu/elec_comp_theses/92 http://iris.lib.neu.edu/elec_comp_theses/92 Tue, 26 Feb 2013 12:03:38 PST Radio Frequency (RF) energy harvesting is relatively unexplored research area, owing to the challenges involved in converting efficiently the low energy density of RF energy in the ambient environment to useful electrical power. The proposed research is aimed at making a case for self-sustaining RF energy harvesting sensors powered by the continuous radiation emitted from external television (TV) stations as part of their scheduled program broadcasts. This thesis explores the prototype design and investigates the limitations of creating such a self-powered network using RF energy harvesting circuits operating around 600 MHz in the VHF digital television broadcast frequency band. A... ]]> David Richard Lewis http://iris.lib.neu.edu/elec_comp_theses/91 http://iris.lib.neu.edu/elec_comp_theses/91 Mon, 25 Feb 2013 10:02:41 PST The objective of the thesis is to design a novel ADPLL with local passive interpolation time-to-digital (LPI-TDC) based on a tri-state inverter for clock synchronization, clock recovery, and noise and jitter suppression in modern microprocessors. When compared to traditional implementations of PLLs, an all-digital approach turns out to be more suitable for the integrated circuits in order to improve overall system timing issues.

In order to accomplish a fast lock of ADPLL, the higher resolution of TDC is needed. An All-Digital Phase-Locked Loop (ADPLL) design is proposed to achieve short locking time using a circuitry of the LPI-TDC based on... ]]> Moon Seok Kim http://iris.lib.neu.edu/elec_comp_theses/90 http://iris.lib.neu.edu/elec_comp_theses/90 Tue, 19 Feb 2013 08:49:51 PST Ground-penetrating radar (GPR) is a mature technology which has developed into a popular tool for subsurface imaging; however its application in landmine detection is still in its infancy. Landmines are typically buried in dispersive soils below a rough surface where the effectiveness of conventional air-coupled GPR is limited. By utilizing ground-contact antennas the signal penetration is dramatically improved and data analysis is simplified. In order to canvas an area while achieving ground-contact with the antennas, this research proposes that the antennas be mounted to the bottom of the feet of a walking robotic platform developed by Square One Systems Design,... ]]> Margery Jeanne Hines http://iris.lib.neu.edu/elec_comp_theses/89 http://iris.lib.neu.edu/elec_comp_theses/89 Fri, 15 Feb 2013 07:57:00 PST Visualization and correct assessment of alveolar volume via intact lung imaging is important to study and assess respiratory mechanics. Optical Coherence Tomography (OCT), a real time imaging technique based on near-infrared interferometry, can image several layers of distal alveoli in intact, ex-vivo lung tissue. However optical effects associated with heterogeneity of lung tissue, including the refraction caused by air-tissue interfaces along alveoli and duct walls, and changes in speed of light as it travels through the tissue, result in inaccurate measurement of alveolar volume. Experimentally such errors have been difficult to analyze because of lack of ''ground truth,'' as the... ]]> Ali Golabchi