Optimized Waveform Relaxation Solution of Electromagnetic and Circuit Problems

New algorithms are needed to solve electromagnetic problems using today\u27s widely available parallel processors. In this paper, we show that applying the optimized waveform relaxation approach to a partial element equivalent circuit will yield a powerful technique for solving electromagnetic problems with the potential for a large number of parallel processor nodes

Custom Integrated Circuits

Contains reports on seven research projects.U.S. Air Force - Office of Scientific Research (Contract F49620-84-C-0004)National Science Foundation (Grant ECS81-18160)Defense Advanced Research Projects Agency (Contract NOO14-80-C-0622)National Science Foundation (Grant ECS83-10941

Delay Extraction based Macromodeling with Parallel Processing for Efficient Simulation of High Speed Distributed Networks

This thesis attempts to address the computational demands of accurate modeling of high speed distributed networks such as interconnect networks and power distribution networks. In order to do so, two different approaches towards modeling of high speed distributed networks are considered. One approach deals with cases where the physical characteristics of the network are not known and the network is characterized by its frequency domain tabulated data. Such examples include long interconnect networks described by their Y parameter data. For this class of problems, a novel delay extraction based IFFT algorithm has been developed for accurate transient response simulation. The other modeling approach is based on a detailed knowledge of the physical and electrical characteristics of the network and assuming a quasi transverse mode of propagation of the electromagnetic wave through the network. Such problems may include two dimensional (2D) and three dimensional (3D) power distribution networks with known geometry and materials. For this class of problem, a delay extraction based macromodeling approaches is proposed which has been found to be able to capture the distributed effects of the network resulting in more compact and accurate simulation compared to the state-of-the-art quasi-static lumped models. Furthermore, waveform relaxation based algorithms for parallel simulations of large interconnect networks and 2D power distribution networks is also presented. A key contribution of this body of work is the identification of naturally parallelizable and convergent iterative techniques that can divide the computational costs of solving such large macromodels over a multi-core hardware

Custom Integrated Circuits

Contains reports on four research projects.U.S. Air Force - Office of Scientific Research (Contract F49620-81-C-0054)U.S. Air Force - Office of Scientific Research (Contract F49620-84-C-0004)National Science Foundation (Grant ECS81-18160)National Science Foundation (Grant ECS83-10941

Optimized Schwarz Waveform Relaxation for Advection Reaction Diffusion Equations in Two Dimensions

Optimized Schwarz Waveform Relaxation methods have been developed over the last decade for the parallel solution of evolution problems. They are based on a decomposition in space and an iteration, where only subproblems in space-time need to be solved. Each subproblem can be simulated using an adapted numerical method, for example with local time stepping, or one can even use a different model in different subdomains, which makes these methods very suitable also from a modeling point of view. For rapid convergence however, it is important to use effective transmission conditions between the space-time subdomains, and for best performance, these transmission conditions need to take the physics of the underlying evolution problem into account. The optimization of these transmission conditions leads to a mathematically hard best approximation problem of homographic type. We study in this paper in detail this problem for the case of linear advection reaction diffusion equations in two spatial dimensions. We prove comprehensively best approximation results for transmission conditions of Robin and Ventcel type. We give for each case closed form asymptotic values for the parameters, which guarantee asymptotically best performance of the iterative methods. We finally show extensive numerical experiments, and we measure performance corresponding to our analysisComment: 42 page

Custom Integrated Circuits

Contains reports on twelve research projects.Analog Devices, Inc.International Business Machines, Inc.Joint Services Electronics Program (Contract DAAL03-86-K-0002)Joint Services Electronics Program (Contract DAAL03-89-C-0001)U.S. Air Force - Office of Scientific Research (Grant AFOSR 86-0164)Rockwell International CorporationOKI Semiconductor, Inc.U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)Charles Stark Draper LaboratoryNational Science Foundation (Grant MIP 84-07285)National Science Foundation (Grant MIP 87-14969)Battelle LaboratoriesNational Science Foundation (Grant MIP 88-14612)DuPont CorporationDefense Advanced Research Projects Agency/U.S. Navy - Office of Naval Research (Contract N00014-87-K-0825)American Telephone and TelegraphDigital Equipment CorporationNational Science Foundation (Grant MIP-88-58764

Biomedical integrated circuit design for an electro-therapy device : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Electronics and Computer Engineering (Bioelectronics) at School of Engineering and Advanced Technology, Massey University, Albany Campus, New Zealand

Journal articles in Appendix A removed for copyright reasons. Chapters 3, 4 and 5 published respectively as: Abbas Al-Darkazly, Ibtisam A., & Hasan, S. M. Rezaul. (2016). A waveform generator circuit for extra low‐frequency CMOS micro‐power applications, International Journal of Circuit Theory and Applications, 44, 266-279. https://doi-org.ezproxy.massey.ac.nz/10.1002/cta.2074 Abbas Al-Darkazly, Ibtisam A., & Hasan, S. M. Rezaul. (2016). Dual-band waveform generator with ultra-wide low-frequency tuning-range, IEEE Access, 4, 3169-3181. DOI: 10.1109/ACCESS.2016.2557843 Abbas Al-Darkazly, Ibtisam A., & Hasan, S. M. Rezaul. (2017). Optimized low-power CMOS active-electrode-pair for low-frequency multi-channel biomedical stimulation, Microelectronics Journal, 66, 18-24. https://doi-org.ezproxy.massey.ac.nz/10.1016/j.mejo.2017.05.014A biomedical integrated circuit design (IC) is utilized for the development of a novel non-invasive electro-therapy device, for low frequency multi-channel biomedical stimulation to transform immune activity and induce anti-viral state. Biomedical integrated circuit design is an important branch of modern electronic engineering that uses the application of electronic engineering principles for biomedical disciplines, to develop bioelectronics devices that are implanted within the body and for non-invasive devices to improve patient’s lives. These devices use the application of an electric field to stimulate reactions to restore normal cell functions and activate the cells to treat a variety of disorders or disease conditions. Bioelectronics devices can be designed for use as alternative treatments to overcome the deficiencies of several conventional medical treatments. It could potentially assist as drug-free relief when therapeutic drugs become ineffective, costly, with serious side effects and cannot be replaced, loss of future treatment options, and hence, life threatening, as for drug resistant Human immunodeficiency virus (HIV-1) patients. Since the underlying mechanisms of the biological system and disease state is dominated by electrostatic interactions, specifically, the interaction between HIV-1 and the host cell that is predominantly by electrostatic interactions (protein charge-charge interaction) has an important role in its life cycle replication. At given pulses, the charge distribution and polarization of the electro-active protein molecules takes place, inducing conformation change which can enhance immune activity and inhibit the interaction of HIV-1 and host cells, disturbing its life cycle, leading to the mechanisms of the inactivation signal-induced virus death. These electrically induced protein transformations is used in this research as blood-cell treatment and as anti-HIV-1 electrotherapy. Advances in bioelectronics technology, which involve new CMOS IC design, and in bio-electrochemistry science, which include cellular function, electro-active biomolecules and their responses, have contributed to this project to develop the concept of a novel electro-therapy device, for biomedical treatment applications. This involves understanding of the underlying mechanisms of the biological system and disease condition from an electronic engineer’s point of view as well as the interface between the electronic signal and the biological cells, and how electronic devices and circuitry directly communicate with the electro-active body tissue and blood cells. This research project addresses the design and development of a novel energy efficient miniature biomedical device using a new CMOS technology. It can generate, deliver and control an appropriate periodical low frequency electrical pulses, through the low-resistance skin surface to a patient’s blood. The notable feature of such a smart device is its cellular specificity: the parameters of the generated electrical pulse which are designed and selected in order to stimulate only one particular type of tissue (blood) leaving the others unaffected. The device comprises a mixed-signal low power dualband waveform generator (WFG) chip along with a novel two band tuning system. It was fabricated using Global Foundries (GF) 8RF-DM 130-nm CMOS process with a supply voltage of ±1V for the analog circuit and +1V for logic circuits. The WFG core (band I) can be tuned in the range 6.44 kHz - 1003 kHz through bias current adjustment, while a lower frequency (band II) in the range 0.1 Hz to 502 kHz can be provided digitally. Two WFG approaches, that comprise relaxation oscillators with different relaxation timing networks, have been developed for comparison. Since the aim of this work is to transfer electrical signal in a specifically controlled fashion through the tissue, a novel low power active electrode-pair signal delivery system, compatible with human skin with high signal integrity, is developed. The circuit was fabricated in a 130-nm CMOS process using a low supply-voltage of +1.2V to deliver bi-phase square waveform signals from 16 selectable low-frequency channels. The individual active electrode can also be used to deliver mono-phase square/triangular waveform output signals. Accuracy, safety, low power, light-weight, miniature and low-cost characteristics are the main concerns. Being a miniature bioelectronics component with low power consumption, the proposed device is suitable both as a non-invasive and as an implantable biomedical device, in which WFG and electrodes circuitry can communicate with the electro-active biomolecule, strongly stimulating certain events in a complex biological system. A theoretical analysis, experiment design and performance are carried out in invitro environments to examine the effect of the designed signal on human blood cellular proteins. Proteins that display a heterogeneous structure have various conductivities and permittivity (determining the interaction with the electrical field) and possess dielectric properties with a large conformation change, undergoing structural rearrangements in response to cellular signals. The frequency-dependent dielectric present in proteins involves the redistribution and alignment of the proteins charged molecule and its polar molecule in response to an applied external electrical field can also induce conformation change. Interference polarization within proteins could interrupt the interaction between both sides of predominantly host cell proteins and of the HIV-1 infective envelope and its protein particles. This could disturb the signalling proteins for cell activation, and, hence, the virus cannot conjugate with the target cells and control the host cell protein activity. Since the virus is unable to reproduce out of a host cell, hence the virus cannot mutate and develop resistance easily, and use alternative binding and entry mechanisms as in the pharmacological approaches. After carefully studying the interaction of the HIV-1 virus and the host cell, with respect to signal transfer, CD4 receptor, co-receptors CCR5 and nuclear transport factor nucleoporins FGNup153 proteins of the lymphatic system, which are essential targets for HIV-1 infection and its life cycle replication represent an attractive target to investigate in this research project. The activities of the underlying mechanism of the target cell are then examined utilizing immunofluorescence microscopy technique with specific fluorescent labelled antibodies, and accurate results are obtained with relatively low cost. The results demonstrated that the low frequency electrical pulse could inhibit virus attachment and fusion. It is also could provide a permeability barrier, that prevents the import and export of large macromolecule virus particles through the nuclear pore complex. These effects could induce an antiviral state for a period of time, and stope HIV-1 virus replication, with no potential risks and harm to the host cells, compared to the common drugs. This is promising for the conception of HIV-1 treatment in vivo. Although further investigations are required in order to fully use the application of electrical stimulation in vivo for treatment, the result is provides the necessary impetus for the applications of low frequency electrical stimulation on human immune response. This might offer important antiviral therapy against the most devastating pathogens in human history. This doctoral research is not only of academic interest but also highly relevant to medical applications. It is considered potentially beneficial in the development of knowledge in advanced technology for electro-medical treatment devices, their design, structure and applications to extend life, and for future growth in the biotechnology industry, therefore beneficial for the patients, physicians and for humanity

Longitudinal Partitioning Waveform Relaxation Methods For The Analysis of Transmission Line Circuits

Three research projects are presented in this manuscript. Projects one and two describe two waveform relaxation algorithms (WR) with longitudinal partitioning for the time-domain analysis of transmission line circuits. Project three presents theoretical results about the convergence of WR for chains of general circuits. The first WR algorithm uses a assignment-partition procedure that relies on inserting external series combinations of positive and negative resistances into the circuit to control the speed of convergence of the algorithm. The convergence of the subsequent WR method is examined, and fast convergence is cast as a generic optimization problem in the frequency-domain. An automatic suboptimal numerical solution of the min-max problem is presented and a procedure to construct its objective function is suggested. Numerical examples illustrate the parallelizability and good scaling of the WR algorithm and point out to the limitation of resistive coupling. In the second WR algorithm, resistances from the previous insertion are replaced with dissipative impedances to address the slow convergence of standard resistive coupling of the first algorithm for low-loss highly reactive circuits. The pertinence and feasibility of impedance coupling are demonstrated and the properties of the subsequent WR method are studied. A new coupling strategy proposes judicious approximations of the optimal convergence conditions for faster speed of convergence. The proposed strategy avoids the difficult problem of optimisation and uses coarse macromodeling of the transmission line to construct approximations with delay under circuit form. Numerical examples confirm a superior speed of convergence which leads to further runtime saving. Finally, new results concerning the nilpotent WR algorithm are presented for chains of circuits when dissipative coupling is used. It is shown that optimal local convergence is necessary to achieve the optimal WR algorithm. However, the converse is not correct: the WR algorithm with optimal local convergences factors can be nilpotent yet not optimal or even be non-nilpotent at all. The second analysis concerns resistive coupling. It is demonstrated that WR always converges for chains circuits. More precisely, it is shown that WR will converge independently of the length of the chain when this late is made of identical symmetric circuits