Design and implementation of NoC routers and their application to Prdt-based NoC\u27s

With a communication-centric design style, Networks-on-Chips (NoCs) emerges as a new paradigm of Systems-on-Chips (SoCs) to overcome the limitations of bus-based communication infrastructure. An important problem in the design of NoCs is the router design, which has great impact on the cost and performance of a NoC system. This thesis is focused on the design and implementation of an optimized parameterized router which can be applied in mesh/torus-based and Perfect Recursive Diagonal Torus (PRDT)-based NoCs; In specific, the router design includes the design and implementation of two routing algorithms (vector routing and circular coded vector routing), the wormhole switching scheme, the scheduling scheme, buffering strategy, and flow control scheme. Correspondingly, the following components are designed and implemented: input controller, output controller, crossbar switch, and scheduler. Verilog HDL codes are generated and synthesized on ASIC platforms. Most components are designed in parameterized way. Performance evaluation of each component of the router in terms of timing, area, and power consumption is conducted. The efficiency of the two routing algorithms and tradeoff between computational time (tsetup) and area are analyzed; To reduce the area cost of the router design, the two major components, the crossbar switch and the scheduler, are optimized. Particularly, for crossbar switch, a comparative study of two crossbar designs is performed with the aid of Magic Layout editor, Synopsys CosmosSE and Awaves; Based on the router design, the PRDT network composed of 4x4 routers is designed and synthesized on ASIC platforms

Non‐Rayleigh Statistics of Ultrasonic Backscattered Echo from Tissues

The envelope of the backscattered signal from tissues can exhibit non‐Rayleigh statistics if the number density of scatterers is small or if the variations in the scattering cross sections are random. The K distribution which has been used extensively in radar, is introduced to model this non‐Rayleigh behavior. The generalized K distribution is extremely useful since it encompasses a wide range of distributions such as Rayleigh, Lognormal, and Rician. Computer simulations were conducted using a simple one‐dimensional discrete scatteringmodel to investigate the properties of the echo envelope. In addition to cases of low number densities, significant departures from Rayleigh statistics were seen as the scattering cross sections of the scatterers become random. The validity of this model was also tested using data from tissue mimicking phantoms. Results indicate that the density function of the envelope can be modeled by the K distribution and the parameters of the K distribution can provide information on the nature of the scattering region in terms of the number density of the scatterers as well as the scattering cross sections of the scatterers in the range cell. [Work was supported by NSF Grant No. BCS‐9207385.

DEVELOPMENT OF A TELEREHABILITATION SOLUTION FOR REMOTE MONITORING AND CARE

Ph.DDOCTOR OF PHILOSOPH

Modularity detection in protein-protein interaction networks

BACKGROUND: Many recent studies have investigated modularity in biological networks, and its role in functional and structural characterization of constituent biomolecules. A technique that has shown considerable promise in the domain of modularity detection is the Newman and Girvan (NG) algorithm, which relies on the number of shortest-paths across pairs of vertices in the network traversing a given edge, referred to as the betweenness of that edge. The edge with the highest betweenness is iteratively eliminated from the network, with the betweenness of the remaining edges recalculated in every iteration. This generates a complete dendrogram, from which modules are extracted by applying a quality metric called modularity denoted by Q. This exhaustive computation can be prohibitively expensive for large networks such as Protein-Protein Interaction Networks. In this paper, we present a novel optimization to the modularity detection algorithm, in terms of an efficient termination criterion based on a target edge betweenness value, using which the process of iterative edge removal may be terminated. RESULTS: We validate the robustness of our approach by applying our algorithm on real-world protein-protein interaction networks of Yeast, C.Elegans and Drosophila, and demonstrate that our algorithm consistently has significant computational gains in terms of reduced runtime, when compared to the NG algorithm. Furthermore, our algorithm produces modules comparable to those from the NG algorithm, qualitatively and quantitatively. We illustrate this using comparison metrics such as module distribution, module membership cardinality, modularity Q, and Jaccard Similarity Coefficient. CONCLUSIONS: We have presented an optimized approach for efficient modularity detection in networks. The intuition driving our approach is the extraction of holistic measures of centrality from graphs, which are representative of inherent modular structure of the underlying network, and the application of those measures to efficiently guide the modularity detection process. We have empirically evaluated our approach in the specific context of real-world large scale biological networks, and have demonstrated significant savings in computational time while maintaining comparable quality of detected modules

Fluid Dynamic and Performance Behavior of Multiphase Progressive Cavity Pumps

It is common for an oil well to produce a mixture of hydrocarbons that flash when exposed to atmospheric pressure. The separation of oil and gas mixtures on site may prove expensive and lead to higher infrastructure and maintenance costs as well. A multiphase pump offers a good alternative with a lower capital cost and increased overall production. A Progressive Cavity Pump (PCP) is a positive displacement pump type that can be used to pump a wide range of multiphase mixtures, including high viscosity fluids with entrained gas and solid particles in suspension. Despite its advantages, a PCP has a reduced ability to handle high gas-liquid ratios due to limitations of its elastomeric stator material required to overcome thermo and mechanical effects. Also the efficiency decreases significantly with increases in gas volume fractions and reduced differential pressures. The current study focuses on studying the behavior of this unique pump in a wide range of GVFs and studying the effect of this ratio on overall efficiency, temperature and pressure distribution on the stator. The pump exhibits vibration issues at specific differential pressures and they have been studied in this work. This can be of critical value as severe vibration issues can damage the pump components such as couplings and bearings leading to high maintenance costs. Another important issue addressed by this research is the behavior of this pump in transient conditions. Oil well production is highly unpredictable with unexpected rises and drops in GVFs. These transient conditions have been simulated by varying the GVF over wide ranges and studying the pump's behavior in terms of load, temperature rises and instantaneous pressure profiles on the pump stator. This thesis provides a comprehensive study of this pump, its operating ranges and behavior in off-design conditions to assist oil and gas exploration ventures in making an informed choice in pump selection for their applications based on field conditions

Experimental Characterization of Adsorption and Transport Properties for Advanced Thermo-Adsorptive Batteries

Thermal energy storage has received significant interest for delivering both heating and cooling in electric vehicles, to minimize the use of the on-board electric batteries for heating, ventilation and air-conditioning (HVAC). An advanced thermoadsorptive battery (ATB) is currently being developed, to provide both heating and cooling for an electric vehicle. We present a detailed thermophysical and physicochemical characterization of adsorptive materials for the development of the ATB. We discuss the feasibility of using contemporary adsorptive materials, such as zeolite 13X, by carrying out a detailed experimental characterization. In this study, zeolite 13X is combined with aluminum hydroxide (Al(OH)3) as a binder to improve the thermal conductivity. We also investigate the effect of densification on the overall transport characteristics of the adsorbent-binder composite material. Accordingly, the effective thermal conductivity, surface area, adsorption capacity and surface chemistry were characterized using the laser flash technique, surface sorption analyzer, thermogravimetric analyzer, and x-ray scattering technique. Thermal conductivity predictions of both zeolite 13X and its combination with the binder were made with existing conductivity models. Thermal conductivity in excess of 0.4 W/mK was achieved with the addition of 6.4 wt.% of Al(OH)3. However, a 10.6 % decrease in adsorption capacity was also observed. The experimental characterization presented herein is an essential step towards the development of the proposed ATB for next-generation electric vehicles. Topics: Experimental characterizationUnited States. Advanced Research Projects Agency-Energ

Diversity in Software Engineering Conferences and Journals

Diversity with respect to ethnicity and gender has been studied in open-source and industrial settings for software development. Publication avenues such as academic conferences and journals contribute to the growing technology industry. However, there have been very few diversity-related studies conducted in the context of academia. In this paper, we study the ethnic, gender, and geographical diversity of the authors published in Software Engineering conferences and journals. We provide a systematic quantitative analysis of the diversity of publications and organizing and program committees of three top conferences and two top journals in Software Engineering, which indicates the existence of bias and entry barriers towards authors and committee members belonging to certain ethnicities, gender, and/or geographical locations in Software Engineering conferences and journal publications. For our study, we analyse publication (accepted authors) and committee data (Program and Organizing committee/ Journal Editorial Board) from the conferences ICSE, FSE, and ASE and the journals IEEE TSE and ACM TOSEM from 2010 to 2022. The analysis of the data shows that across participants and committee members, there are some communities that are consistently significantly lower in representation, for example, publications from countries in Africa, South America, and Oceania. However, a correlation study between the diversity of the committees and the participants did not yield any conclusive evidence. Furthermore, there is no conclusive evidence that papers with White authors or male authors were more likely to be cited. Finally, we see an improvement in the ethnic diversity of the authors over the years 2010-2022 but not in gender or geographical diversity.Comment: 13 pages, 10 figures, 4 table

Path-Integral Formula for Computing Koopman Eigenfunctions

The paper is about the computation of the principal spectrum of the Koopman operator (i.e., eigenvalues and eigenfunctions). The principal eigenfunctions of the Koopman operator are the ones with the corresponding eigenvalues equal to the eigenvalues of the linearization of the nonlinear system at an equilibrium point. The main contribution of this paper is to provide a novel approach for computing the principal eigenfunctions using a path-integral formula. Furthermore, we provide conditions based on the stability property of the dynamical system and the eigenvalues of the linearization towards computing the principal eigenfunction using the path-integral formula. Further, we provide a Deep Neural Network framework that utilizes our proposed path-integral approach for eigenfunction computation in high-dimension systems. Finally, we present simulation results for the computation of principal eigenfunction and demonstrate their application for determining the stable and unstable manifolds and constructing the Lyapunov function

Design of flexible spot welding cell for Body-In-White (BIW) assembly

In this paper, a flexible spot welding cell - which is flexible both at fixture and work cell level is developed to handle multiple Body-In-White (BIW) part varieties. The work-cell is a human-robot cooperative cell where the operator loads/unloads the parts on one side, whereas the robot concurrently performs welding operation on other side. The fixture is made modular and is reconfigured for change in part varieties. The flexibility of proposed work cell and fixture are investigated and validated by considering two different BIW spot weld assemblies. The performance of robot, cycle time estimation for the process, checking of fixtures, collision detection between weld gun and fixtures are evaluated in virtual environment. The flexible weld cell is proved to be compatible for both the BIW assemblies considered for study. The proposed concept shorten the design & fabrication time of fixture - squeezing the investment cost, assembly cost and floor space; besides reducing the cycle time and improving the robot utilization by 30% - 40% when compared to the conventional method