460 research outputs found

    Effective network grid synthesis and optimization for high performance very large scale integration system design

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    制度:新 ; 文部省報告番号:甲2642号 ; 学位の種類:博士(工学) ; 授与年月日:2008/3/15 ; 早大学位記番号:新480

    Crexens™: an expandable general-purpose electrochemical analyzer

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    2019 Fall.Includes bibliographical references.Electrochemical analysis has gained a great deal of attention of late due to its low-cost, easy-to-perform, and easy-to-miniaturize, especially in personal health care where accuracy and mobility are key factors to bring diagnostics to patients. According to data from Centers for Medicare & Medicaid Services (CMS) in the US, the share of health expenditure in the US has been kept growing in the past 3 decades and reached 17.9% of its overall Gross Domestic Product till 2016, which is equivalent to 10,348foreverypersonintheUSperyear.Ontheotherhand,healthcareresourcesareoftenlimitednotonlyinruralareabutalsoappearedinwelldevelopedcountries.TheurgentneedandthelackofhealthresourcebringstofronttheresearchinterestofPointofCare(PoC)diagnosisdevices.Electrochemicalmethodshavebeenlargelyadoptedbychemistandbiologistfortheirresearchpurposes.However,severalissuesexistwithincurrentcommercialbenchtopinstrumentsforelectrochemicalmeasurement.Firstofall,thecurrentcommercialinstrumentsareusuallybulkyanddonothavehandheldfeatureforpointofcareapplicationsandthecostareeasilynear10,348 for every person in the US per year. On the other hand, health care resources are often limited not only in rural area but also appeared in well-developed countries. The urgent need and the lack of health resource brings to front the research interest of Point-of-Care (PoC) diagnosis devices. Electrochemical methods have been largely adopted by chemist and biologist for their research purposes. However, several issues exist within current commercial benchtop instruments for electrochemical measurement. First of all, the current commercial instruments are usually bulky and do not have handheld feature for point-of-care applications and the cost are easily near 5,000 each or above. Secondly, most of the instruments do not have good integration level that can perform different types of electrochemical measurements for different applications. The last but not the least, the existing generic benchtops instruments for electrochemical measurements have complex operational procedures that require users to have a sufficient biochemistry and electrochemistry background to operate them correctly. The proposed Crexens™ analyzer platform is aimed to present an affordable electrochemical analyzerwhile achieving comparable performance to the existing commercial instruments, thus, making general electrochemical measurement applications accessible to general public. In this dissertation, the overall Crexens™ electrochemical analyzer architecture and its evolution are presented. The foundation of the Crexens™ architecture was derived from two separate but related research in electrochemical sensing. One of them is a microelectrode sensor array using CMOS for neurotransmitter sensing; the other one is a DNA affinity-based capacitive sensor for infectious disease, such as ZIKA. The CMOS microelectrode sensor array achieved a 320uM sensitivity for norepinephrine, whereas the capacitive sensor achieved a dynamic range of detection from 1 /uL to 105 /uL target molecules (20 to 2 million targets), which makes it be within the detection range in a typical clinical application environment. This dissertation also covers the design details of the CMOS microelectrode array sensor and the capacitive sensor design as a prelude to the development of the Crexens™ analyzer architecture. Finally, an expandable integrated electrochemical analyzer architecture (Crexens™) has been designed for mobile point-of-care (POC) applications. Electrochemical methods have been explored in detecting various bio-molecules such as glucose, lactate, protein, DNA, neurotransmitter, steroid hormone, which resulted in good sensitivity and selectivity. The proposed system is capable of running electrochemical experiments including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), electrochemical capacitive spectroscopy (ECS), amperometry, potentiometry, and other derived electrochemical based tests. This system consist of a front-end interface to sensor electrodes, a back-end user interface on smart phone and PC, a base unit as master module, a low-noise add-on module, a high-speed add-on module, and a multi-channel add-on module. The architecture allows LEGO™-like capability to stack add-on modules on to the base-unit for performance enhancements in noise, speed or parallelism. The analyzer is capable of performing up to 1900 V/s CV with 10 mV step, up to 12 kHz EIS scan range and a limit of detection at 637 pA for amperometric applications with the base module. With high performance module, the EIS scan range can be extended upto 5 MHz. The limit of detection can be further improved to be at 333 fA using the low-noise module. The form factor of the electrochemical analyzer is designed for its mobile/point-of-care applications, integrating its entire functionality on to a 70 cm² area of surface space. A glutamine enzymatic sensor was used to valid the capability of the proposed electrochemical analyzer and turned out to give good linearity and reached a limit of detection at 50 uM

    VLSI Design

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    This book provides some recent advances in design nanometer VLSI chips. The selected topics try to present some open problems and challenges with important topics ranging from design tools, new post-silicon devices, GPU-based parallel computing, emerging 3D integration, and antenna design. The book consists of two parts, with chapters such as: VLSI design for multi-sensor smart systems on a chip, Three-dimensional integrated circuits design for thousand-core processors, Parallel symbolic analysis of large analog circuits on GPU platforms, Algorithms for CAD tools VLSI design, A multilevel memetic algorithm for large SAT-encoded problems, etc

    NASA SERC 1990 Symposium on VLSI Design

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    This document contains papers presented at the first annual NASA Symposium on VLSI Design. NASA's involvement in this event demonstrates a need for research and development in high performance computing. High performance computing addresses problems faced by the scientific and industrial communities. High performance computing is needed in: (1) real-time manipulation of large data sets; (2) advanced systems control of spacecraft; (3) digital data transmission, error correction, and image compression; and (4) expert system control of spacecraft. Clearly, a valuable technology in meeting these needs is Very Large Scale Integration (VLSI). This conference addresses the following issues in VLSI design: (1) system architectures; (2) electronics; (3) algorithms; and (4) CAD tools

    NASA Space Engineering Research Center Symposium on VLSI Design

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    The NASA Space Engineering Research Center (SERC) is proud to offer, at its second symposium on VLSI design, presentations by an outstanding set of individuals from national laboratories and the electronics industry. These featured speakers share insights into next generation advances that will serve as a basis for future VLSI design. Questions of reliability in the space environment along with new directions in CAD and design are addressed by the featured speakers

    Engineering Education and Research Using MATLAB

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    MATLAB is a software package used primarily in the field of engineering for signal processing, numerical data analysis, modeling, programming, simulation, and computer graphic visualization. In the last few years, it has become widely accepted as an efficient tool, and, therefore, its use has significantly increased in scientific communities and academic institutions. This book consists of 20 chapters presenting research works using MATLAB tools. Chapters include techniques for programming and developing Graphical User Interfaces (GUIs), dynamic systems, electric machines, signal and image processing, power electronics, mixed signal circuits, genetic programming, digital watermarking, control systems, time-series regression modeling, and artificial neural networks

    Inverter design and analysis using multiple reference frame theory

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    Multiple reference frame theory allows for periodically time varying signals to be represented as a set of dc signals. In other words, every periodic signal can be expanded into a Fourier series representation. By modeling an inverter connected to a boost maximum power point tracker (MPPT) in this manner, frequency transfer properties can be preserved and harmonics throughout the system can be predicted. A state space model taking into account the dc and fundamental grid frequency is presented and used to optimize the controller gains of the system. Using information from the dq-axis values of the measured grid current and voltage, the double frequency dc-link voltage component is predicted. The double frequency component is removed from the controller input using feedforward. As a result, there is a reduction in output harmonics in the grid current. The same method is applied to the MPPT, where the double frequency component is predicted and removed from the controller input. This allows for a MPPT with reduced oscillations in the input power waveform. Next, a method is presented to generate a large-signal model of a H-bridge inverter. A set of algorithms are presented, which take a standard set of large-signal (user generated) dynamic equations and performs a Fourier series expansion on the inputs and states of the equations. These algorithms work for an arbitrary finite set of harmonics and preserve the frequency transfer properties between harmonics. The solution to the generated equations is the steady state output of the inverter. Lastly, a set of algorithms are presented which take a user generated netlist in and automatically outputs a truncated harmonic transfer function (THTF) --Abstract, page iii

    An enhanced feedforward flux weakening control for high‐speed permanent magnet machine drive applications

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    Permanent magnet machines have been used in the high-speed drive applications due to their high-efficiency, high-power-density, and wide-speed range characteristics. However, control of such high-speed permanent magnet machines machine is always challenging and proper flux-weakening controller design is essential to achieve high performance of these machines. In this paper, an improved feedforward flux-weakening control scheme for interior permanent magnet synchronous machine (IPMSM) drives are proposed. The proposed method identifies optimal d-axis and q-axis currents under different operation regions using maximum-torque-per-ampere curve, voltage limit, and current limit curves with a fast Newton–Raphson algorithm. To ensure the optimal performance of the control mechanism, effects of inductance variations due to the magnetic saturation are considered and an innovative high-frequency staircase voltage injection method is used to identify the q-axis inductance. The experimental results show that compared with other existing flux-weakening methods, the proposed technique can improve the DC-link voltage utilisation without the need to tune any controller gains and can fully utilise maximum available torque with desirable transient performance
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