A Practical Investigation into Achieving Bio-Plausibility in Evo-Devo Neural Microcircuits Feasible in an FPGA

Many researchers has conjectured, argued, or in some cases demonstrated, that bio-plausibility can bring about emergent properties such as adaptability, scalability, fault-tolerance, self-repair, reliability, and autonomy to bio-inspired intelligent systems. Evolutionary-developmental (evo-devo) spiking neural networks are a very bio-plausible mixture of such bio-inspired intelligent systems that have been proposed and studied by a few researchers. However, the general trend is that the complexity and thus the computational cost grow with the bio-plausibility of the system. FPGAs (Field- Programmable Gate Arrays) have been used and proved to be one of the flexible and cost efficient hardware platforms for research' and development of such evo-devo systems. However, mapping a bio-plausible evo-devo spiking neural network to an FPGA is a daunting task full of different constraints and trade-offs that makes it, if not infeasible, very challenging. This thesis explores the challenges, trade-offs, constraints, practical issues, and some possible approaches in achieving bio-plausibility in creating evolutionary developmental spiking neural microcircuits in an FPGA through a practical investigation along with a series of case studies. In this study, the system performance, cost, reliability, scalability, availability, and design and testing time and complexity are defined as measures for feasibility of a system and structural accuracy and consistency with the current knowledge in biology as measures for bio-plausibility. Investigation of the challenges starts with the hardware platform selection and then neuron, cortex, and evo-devo models and integration of these models into a whole bio-inspired intelligent system are examined one by one. For further practical investigation, a new PLAQIF Digital Neuron model, a novel Cortex model, and a new multicellular LGRN evo-devo model are designed, implemented and tested as case studies. Results and their implications for the researchers, designers of such systems, and FPGA manufacturers are discussed and concluded in form of general trends, trade-offs, suggestions, and recommendations

Design of a man-wearable control station for a robotic rescue system

This report details the design, development, and testing of a man-wearable operator control station for the use of a low-cost robotic system in Urban Search and Rescue (USAR). The complete system, dubbed the "Scarab", is the 1st generation developed and built in the Robotics and Agents Research Laboratory (RARL) at the University of Cape Town (UCT), and was a joint effort between three MSc students. Robots have found a place in USAR as replaceable units which can be deployed into dangerous and confined voids in the place of humans. As such, they have been utilized in a large variety of disaster environments including ground, aerial, and underwater scenarios, and have been gathering research momentum since their first documented deployment in the rescue operations surrounding the 9/11 terrorist attacks. However one issue is their cost as they are not economical solutions, making them less viable for inclusion into a rescue mission as well as negatively affecting the operator‟s decisions in order to prioritise the safety of the unit. Another concern is their difficulty of transport, which becomes dependent on the size and portability of the robot. As such, the Scarab system was conceived to provide a deployable robotic platform which was lowcost, with a budget goal of US $ 500. To address the transportability concerns, it aimed to be portable and light-weight; being able to be thrown through a window by a single hand and withstanding a drop height of 3 m. It includes an internal sensor payload which incorporates an array of sensors and electronics, including temperature monitors and two cameras to provide both a normal and IR video feed. Two LED spotlights are used for navigation, and a microphone and buzzer is included for interaction with any discovered survivors. The operator station acts as the user interface between the operator and the robotic platform. It aimed to be as intuitive as possible, providing quick deployment and minimalizing the training time required for its operation. To further enhance the Scarab system‟s portability, it was designed to be a manwearable system, allowing the operator to carry the robotic platform on their back. It also acts as a charging station, supplying power to the robotic platform‟s on-board charging circuitry. The control station‟s mechanical chassis serves as the man-wearable component of the system, with the functionality being achieved by integration onto a tactical vest. This allows the operator to take the complete system on and off as a single unit without assistance, and uses two mounting brackets to dock the robotic platform. Key areas focussed upon during design were the weight and accessibility of the system, as well as providing a rugged housing for the internal electronics. All parts were manufactured in the UCT Mechanical Engineering workshop

Trade-off analysis of modes of data handling for earth resources (ERS), volume 1

Data handling requirements are reviewed for earth observation missions along with likely technology advances. Parametric techniques for synthesizing potential systems are developed. Major tasks include: (1) review of the sensors under development and extensions of or improvements in these sensors; (2) development of mission models for missions spanning land, ocean, and atmosphere observations; (3) summary of data handling requirements including the frequency of coverage, timeliness of dissemination, and geographic relationships between points of collection and points of dissemination; (4) review of data routing to establish ways of getting data from the collection point to the user; (5) on-board data processing; (6) communications link; and (7) ground data processing. A detailed synthesis of three specific missions is included

Proceedings of the Second Caltech Conference on Very Large Scale Integration, held at the California Institute of Technology 19-21 January, 1981 ; Organized by the Caltech Computer Science Department and the Caltech Industrial Associates Office, and sponsored by Caltech Industrial Associates and the National Science Foundation

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A low voltage 900 MHz CMOS mixer.

by Cheng Wang Chi.Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.Includes bibliographical references (leaves 108-111).Abstracts in English and Chinese.Abstract --- p.i摘要 --- p.iiiAcknowledgments --- p.vContents --- p.viiList of Tables --- p.xiiiList of Figures --- p.xivChapter Chapter1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.2 --- Technical Challenges of CMOS RF Design --- p.2Chapter 1.3 --- General Background --- p.2Chapter 1.3.1 --- Bipolar and CMOS Mixers --- p.4Chapter 1.4 --- Research Goal --- p.4Chapter 1.5 --- Thesis Outline --- p.5Chapter Chapter2 --- RF Fundamentals --- p.6Chapter 2.1 --- Introduction --- p.6Chapter 2.2 --- Frequency Translation --- p.6Chapter 2.3 --- Conversion Gain --- p.8Chapter 2.4 --- Linearity --- p.8Chapter 2.4.1 --- 1-dB Compression Point --- p.11Chapter 2.4.2 --- Third Intercept Point (IP3) --- p.11Chapter 2.5 --- Dynamic Range (DR) --- p.13Chapter 2.5.1 --- Spurious-Free Dynamic Range (SFDR) --- p.13Chapter 2.5.2 --- Blocking Dynamic Range (BDR) --- p.14Chapter 2.6 --- Blocking and Desensitization --- p.15Chapter 2.7 --- Port-to-Port Isolation --- p.15Chapter 2.8 --- Single-Balanced and Double-Balanced Mixers --- p.16Chapter 2.9 --- Noise --- p.16Chapter 2.9.1 --- Noise in the Local Oscillator --- p.17Chapter 2.9.2 --- Noise Figure --- p.18Chapter Chapter3 --- Downconversion Mixer --- p.19Chapter 3.1 --- Introduction --- p.19Chapter 3.2 --- Review of Mixer Topology --- p.19Chapter 3.2.1 --- Square-Law Mixer --- p.20Chapter 3.2.2 --- CMOS Gilbert Cell --- p.21Chapter 3.2.3 --- Potentiometric Mixer --- p.22Chapter 3.2.4 --- Subsampling Mixer --- p.23Chapter Chapter4 --- Proposed Downconversion Mixer --- p.24Chapter 4.1 --- Analysis of Proposal Mixer --- p.24Chapter 4.2 --- Current Folded Mirror Mixer --- p.24Chapter 4.2.1 --- Operating Principle --- p.25Chapter 4.2.2 --- Large Signal Analysis --- p.26Chapter 4.2.3 --- Small Signal Analysis --- p.29Chapter 4.3 --- Current Mode Mixer --- p.32Chapter 4.3.1 --- Operating Principle --- p.33Chapter 4.3.2 --- Large Signal Analysis --- p.33Chapter 4.3.3 --- Small Signal Analysis --- p.34Chapter 4.3.4 --- V-I Converter --- p.36Chapter 4.3.4.1 --- Equation Analysis --- p.37Chapter 4.4 --- Second Order Effects --- p.38Chapter 4.4.1 --- Device Mismatch --- p.38Chapter 4.4.2 --- Body Effect --- p.39Chapter 4.5 --- Single-ended to Differential-ended converter --- p.39Chapter 4.6 --- Output Buffer Stage --- p.40Chapter 4.7 --- Noise Theory --- p.41Chapter 4.7.1 --- SSB and DSB Noise Figure --- p.42Chapter 4.7.2 --- Noise Figure --- p.43Chapter Chapter5 --- Simulation Results --- p.44Chapter 5.1 --- Introduction --- p.44Chapter 5.2 --- Current Folded Mirror Mixer --- p.44Chapter 5.2.1 --- Conversion Gain --- p.45Chapter 5.2.2 --- Linearity --- p.46Chapter 5.2.2.1 --- 1dB Compression Point and IIP3 --- p.49Chapter 5.2.3 --- Output Buffer Stage --- p.49Chapter 5.3 --- Current Mode Mixer --- p.51Chapter 5.3.1 --- Conversion Gain --- p.51Chapter 5.3.2 --- Linearity --- p.52Chapter 5.3.2.1 --- 1-dB Compression Point and IIP3 --- p.52Chapter 5.3.3 --- Output Buffer Stage --- p.53Chapter 5.3.4 --- V-I Converter --- p.54Chapter 5.4 --- Single-ended to Differential-ended Converter --- p.55Chapter Chapter6 --- Layout Consideration --- p.57Chapter 6.1 --- Introduction --- p.57Chapter 6.2 --- CMOS transistor Layout --- p.57Chapter 6.3 --- Resistor Layout --- p.59Chapter 6.4 --- Capacitor Layout --- p.60Chapter 6.5 --- Substrate Tap --- p.62Chapter 6.6 --- Pad Layout --- p.63Chapter 6.7 --- Analog Cell Layout --- p.64Chapter Chapter7 --- Measurements --- p.65Chapter 7.1 --- Introduction --- p.65Chapter 7.2 --- Downconversion mixer --- p.66Chapter 7.3 --- PCB Layout --- p.66Chapter 7.4 --- Test Setups --- p.68Chapter 7.4.1 --- Measurement Setup for S-Parameter --- p.68Chapter 7.4.2 --- Measurement Setup for 1-dB Compression Point and IIP3 --- p.70Chapter 7.5 --- Measurement Result of the Current Folded Mirror Mixer --- p.72Chapter 7.5.1 --- S-Parameter Measurement --- p.75Chapter 7.5.2 --- Conversion Gain and the Effect of the IF Variation --- p.77Chapter 7.5.3 --- 1-dB Compression Point --- p.78Chapter 7.5.4 --- IIP3 --- p.79Chapter 7.5.5 --- LO Power Effect to the Mixer --- p.81Chapter 7.5.6 --- Performance Summaries of the Current Folded Mirror Mixer --- p.82Chapter 7.5.7 --- Discussion --- p.83Chapter 7.6 --- Measurement Result of the Current Mode Mixer --- p.84Chapter 7.6.1 --- S-Parameter Measurement --- p.87Chapter 7.6.2 --- Conversion Gain and the Effect of the IF Variation --- p.89Chapter 7.6.3 --- 1-dB Compression Point --- p.90Chapter 7.6.4 --- IIP3 --- p.91Chapter 7.6.5 --- LO Power Effect to the Mixer --- p.93Chapter 7.6.6 --- Performance Summaries of the Current Mode Mixer --- p.94Chapter 7.6.7 --- Discussion --- p.95Chapter 7.7 --- Measurement Result of the Single-ended to Differential-ended converter --- p.96Chapter 7.7.1 --- Measurement Setup for the Phase Difference --- p.97Chapter 7.7.2 --- Phase Difference Measurement --- p.98Chapter 7.7.3 --- Discussion --- p.99Chapter Chapter8 --- Conclusion --- p.100Chapter Appendix A --- Characteristics of the Gilbert Quad Pair --- p.102Chapter A.1 --- Large-Signal Analysis --- p.102Chapter Appendix B --- Characteristics of the V-I Converter --- p.105Chapter B.1 --- Large-Signal Analysis --- p.105Bibliography --- p.10

Technology 2000, volume 1

The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity

An investigation into multi-spectral excitation power sources for Electrical Impedance Tomography

Electrical Impedance Tomography is a non-invasive, non-ionizing, non-destructive and painless imaging technology that can distinguish between cancerous and non-cancerous cells by reproducing tomographic images of the electrical impedance distribution within the body. The primary scope of this thesis is the study of hardware modules required for an EIT system. The key component in any EIT system is the excitation system. Impedance measurement can be performed by applying either a current or voltage through emitting electrodes and then measuring the resulting voltages or current on receiving electrodes. In this research, both types of excitation systems are investigated and developed for the Sussex EIM system. Firstly, a current source (CS) excitation system is investigated and developed. The performance of the excitation system degrades due to the unwanted capacitance within the system. Hence two CS circuits: Enhance Howland Source (EHS) and EHS combined with a General impedance convertor (GIC: to minimise the unwanted capacitance) are evaluated. Another technique (guard-amplifier) has also been investigated and developed to minimise the effect of stray capacitance. The accuracy of both types of CS circuits are evaluated in terms of its output impedance along with other performance parameters for different loading conditions and the results are compared to show their performance. Both CS circuits were affected by the loading voltage problem. A bootstrapping technique is investigated and integrated with both CS circuits to overcome the loading voltage problem. The research shows that both CS circuits were unable to achieve a high frequency bandwidth (i.e. ≥10MHz) and were limited to 2-3MHz. Alternatively, a discrete components current source was also investigated and developed to achieve a high frequency bandwidth and other desirable performance parameters. The research also introduces a microcontroller module to control the multiplexing involved for different CS circuit configurations via serial port interface software running on a PC. For breast cancer diagnosis, the interesting characteristics of breast tissues mostly lie above 1MHz, therefore a wideband excitation source covering high frequencies (i.e. ≥1-10MHz) is required. Hence, a second type of the excitation system is investigated. A constant voltage source (VS) circuit was developed for a wide frequency bandwidth with low output impedance. The research investigated three VS architectures and based on their initial bandwidth comparison, a differential VS system was developed to provide a wide frequency bandwidth (≥10MHz). The research presents the performance of the developed VS excitation system for different loading configurations reporting acceptable performance parameters. A voltage measurement system is also developed in this research work. Two different differential amplifier circuits were investigated and developed to measure precise differential voltage at a high frequency. The research reports a performance comparison of possible types of excitation systems. Results are compared to establish their relationship to performance parameters: frequency bandwidth, output impedance, SNR and phase difference over a wide bandwidth (i.e. up to 10MHz). The objective of this study is to investigate which design is the most appropriate for constructing a wideband excitation system for the Sussex EIM system or any other EIT based biomedical application with wide a bandwidth requirement

An investigation into multi-spectral excitation power sources for Electrical Impedance Tomography

Electrical Impedance Tomography is a non-invasive, non-ionizing, non-destructive and painless imaging technology that can distinguish between cancerous and non-cancerous cells by reproducing tomographic images of the electrical impedance distribution within the body. The primary scope of this thesis is the study of hardware modules required for an EIT system. The key component in any EIT system is the excitation system. Impedance measurement can be performed by applying either a current or voltage through emitting electrodes and then measuring the resulting voltages or current on receiving electrodes. In this research, both types of excitation systems are investigated and developed for the Sussex EIM system. Firstly, a current source (CS) excitation system is investigated and developed. The performance of the excitation system degrades due to the unwanted capacitance within the system. Hence two CS circuits: Enhance Howland Source (EHS) and EHS combined with a General impedance convertor (GIC: to minimise the unwanted capacitance) are evaluated. Another technique (guard-amplifier) has also been investigated and developed to minimise the effect of stray capacitance. The accuracy of both types of CS circuits are evaluated in terms of its output impedance along with other performance parameters for different loading conditions and the results are compared to show their performance. Both CS circuits were affected by the loading voltage problem. A bootstrapping technique is investigated and integrated with both CS circuits to overcome the loading voltage problem. The research shows that both CS circuits were unable to achieve a high frequency bandwidth (i.e. ≥10MHz) and were limited to 2-3MHz. Alternatively, a discrete components current source was also investigated and developed to achieve a high frequency bandwidth and other desirable performance parameters. The research also introduces a microcontroller module to control the multiplexing involved for different CS circuit configurations via serial port interface software running on a PC. For breast cancer diagnosis, the interesting characteristics of breast tissues mostly lie above 1MHz, therefore a wideband excitation source covering high frequencies (i.e. ≥1-10MHz) is required. Hence, a second type of the excitation system is investigated. A constant voltage source (VS) circuit was developed for a wide frequency bandwidth with low output impedance. The research investigated three VS architectures and based on their initial bandwidth comparison, a differential VS system was developed to provide a wide frequency bandwidth (≥10MHz). The research presents the performance of the developed VS excitation system for different loading configurations reporting acceptable performance parameters. A voltage measurement system is also developed in this research work. Two different differential amplifier circuits were investigated and developed to measure precise differential voltage at a high frequency. The research reports a performance comparison of possible types of excitation systems. Results are compared to establish their relationship to performance parameters: frequency bandwidth, output impedance, SNR and phase difference over a wide bandwidth (i.e. up to 10MHz). The objective of this study is to investigate which design is the most appropriate for constructing a wideband excitation system for the Sussex EIM system or any other EIT based biomedical application with wide a bandwidth requirement

Index to NASA tech briefs, 1971

The entries are listed by category, subject, author, originating source, source number/Tech Brief number, and Tech Brief number/source number. There are 528 entries