1980 Preface * 1999 Preface * 1999 Acknowledgements * Introduction * 1 Circular Logic * 2 Phase Singularities (Screwy Results of Circular Logic) * 3 The Rules of the Ring * 4 Ring Populations * 5 Getting Off the Ring * 6 Attracting Cycles and Isochrons * 7 Measuring the Trajectories of a Circadian Clock * 8 Populations of Attractor Cycle Oscillators * 9 Excitable Kinetics and Excitable Media * 10 The Varieties of Phaseless Experience: In Which the Geometrical Orderliness of Rhythmic Organization Breaks Down in Diverse Ways * 11 The Firefly Machine 12 Energy Metabolism in Cells * 13 The Malonic Acid Reagent ('Sodium Geometrate') * 14 Electrical Rhythmicity and Excitability in Cell Membranes * 15 The Aggregation of Slime Mold Amoebae * 16 Numerical Organizing Centers * 17 Electrical Singular Filaments in the Heart Wall * 18 Pattern Formation in the Fungi * 19 Circadian Rhythms in General * 20 The Circadian Clocks of Insect Eclosion * 21 The Flower of Kalanchoe * 22 The Cell Mitotic Cycle * 23 The Female Cycle * References * Index of Names * Index of Subjects

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/596B270197FE27DE5FABB598B6210622/S0025557200150892a.pdf/div-class-title-span-class-italic-the-geometry-of-biological-time-span-by-a-t-winfree-pp-544-dm68-corrected-second-printing-1990-isbn-3-540-52528-9-springer-div.pdf

The geometry of biological time , by A. T. Winfree. Pp 544. DM68. Corrected Second Printing 1990. ISBN 3-540-52528-9 (Springer)

https://users.dimi.uniud.it/~antonio.dangelo/Robotica/2012/helper/leggedRobot/Ijspeert08NN.pdf

2008 Special Issue: Central pattern generators for locomotion control in animals and robots: A review

The goal of this paper is to review in brief the basic physics of single-election devices, as well as their-current and prospective applications. These devices based on the controllable transfer of single electrons between small conducting "islands", have already enabled several important scientific experiments. Several other applications of analog single-election devices in unique scientific instrumentation and metrology seem quite feasible. On the other hand, the prospect of silicon transistors being replaced by single-electron devices in integrated digital circuits faces tough challenges and remains uncertain. Nevertheless, even if this replacement does not happen, single electronics will continue to play an important role by shedding light on the fundamental size limitations of new electronic devices. Moreover, recent research in this field has generated some by-product ideas which may revolutionize random-access-memory and digital-data-storage technologies.

Single-electron devices and their applications

The electronic properties of inorganic devices such as memristors can be used to simulate neurological behaviour. In particular, ionic and electronic effects in a silver sulphide device are now shown to mimic short- and long-term synaptic functions. Memory is believed to occur in the human brain as a result of two types of synaptic plasticity: short-term plasticity (STP) and long-term potentiation (LTP; refs 1, 2, 3, 4). In neuromorphic engineering5,6, emulation of known neural behaviour has proven to be difficult to implement in software because of the highly complex interconnected nature of thought processes. Here we report the discovery of a Ag2S inorganic synapse, which emulates the synaptic functions of both STP and LTP characteristics through the use of input pulse repetition time. The structure known as an atomic switch7,8, operating at critical voltages, stores information as STP with a spontaneous decay of conductance level in response to intermittent input stimuli, whereas frequent stimulation results in a transition to LTP. The Ag2S inorganic synapse has interesting characteristics with analogies to an individual biological synapse, and achieves dynamic memorization in a single device without the need of external preprogramming. A psychological model related to the process of memorizing and forgetting is also demonstrated using the inorganic synapses. Our Ag2S element indicates a breakthrough in mimicking synaptic behaviour essential for the further creation of artificial neural systems that emulate characteristics of human memory.

/pdf/short-term-plasticity-and-long-term-potentiation-mimicked-in-3c6onjbc0r.pdf

Short-term plasticity and long-term potentiation mimicked in single inorganic synapses

Computational geometry

We present an inhibitory neural network implemented on analog CMOS chips, whose neurons compete with each other in the frequency and time domains. The circuit for each neuron was designed to produce sequences in time of identically shaped pulses, called spikes. The results of experiments and simulations revealed that the network more efficiently achieved the selective activation and inactivation of the neural circuits on the basis of spike timing than on the basis of firing rates. The results indicate that neural processing based on the spike timing of neural circuits provides a possible way to overcome the low-tolerance problems of analog devices in noisy environments.

Frequency- and temporal-domain neural competition in analog integrate-and-fire neurochips

Fig. 1. Schematic of the proposed current reference circuit. Intelligent network systems for the future will require a great number of smart sensor LSIs that measure various physical data in surroundings. These LSIs have to operate with a low power, tens of microwatts or less, because they will probably be placed in non-ideal environments where energy for operation cannot be obtained sufficiently. To achieve such ultra-low power operation, CMOS circuits in sensor LSIs have to be operated in the subthreshold region of MOSFETs. For this purpose, we need to develop a circuit that provides a small reference current of less than tens of nanoamperes for the subthreshold CMOS circuits. We propose such a reference current circuit that is insensitive to temperature and power supply voltage. Current references for subthreshold CMOS circuits have been proposed by Oguey and Aebischer [1], and Hirose and others [2, 3]. The former current reference, however, shows a positive temperature coefficient of output current. The latter shows a zero temperature coefficient but consists of a complex circuit with many MOSFETs. Therefore, they are unsuitable for our purpose. The current reference circuit we propose will solve these problems and can be used for lowpower subthreshold MOS LSIs. The following describes the details of our current reference circuit.

/pdf/current-reference-circuit-for-subthreshold-cmos-lsis-3fqu8n48xb.pdf

Current Reference Circuit for Subthreshold CMOS LSIs

A new planarization technique in the LSI process utilizing Si-Ge film oxidation is proposed. The Si-Ge film is deposited by the thermal decomposition of SiH4 and GeH4 and then oxidized in wet O2 ambient. During the oxidation, a large degree of fluidity appears below 800°C, a temperature much lower than that needed for phosphosilicate glass flow. The oxide growth rate is more than one order of magnitude higher than that in crystalline Si. The oxide thickness decreases with increasing Ge content and oxidation temperature, owing to Ge evaporation. This planarization is related to Ge evaporation. After the entire Si-Ge film has been oxidized, neither glass flow nor Ge evaporation occur, even at temperatures higher than that of the oxidation. The electrical properties of the Si-Ge oxide film are good enough for its use as an insulating layer. The film does not react with an underlying SiO2 or Si3N4 layer.

A New Planarization Technique for LSI Fabrication Utilizing Si-Ge Film Oxidation

Neuromorphic computing based on single-electron circuit technology has become widely noticed because of the recent claim about its massively increased computational efficiency and its increasing relevance between computer technology and nanotechnology. Its impact will be strongly felt when single-electron circuits based on a fault- and noise-tolerant neural structure are able to operate in a room-temperature environment. To fabricate such robust single-electron devices, we investigated stochastic resonance in an ensemble of single-electron boxes. We here employ a single-electron transistor on a Schottky wrap-gate device, instead of a single-electron box, as a neuron, and examine statistical results of the network by numerical simulation.

Stochastic resonance among single-electron neurons on Schottky wrap-gate device

The junctions between low-pressure CVD a-Si-Ge-B and n-type crystalline GaAs are characterized through detailed investigation of the barrier heights. The a-Si-Ge-B/GaAs junction is similar to the metal/GaAs junction. However, the barrier height of the former, which depends on the composition of the a-Si-Ge-B, is far larger than the maximum barrier height of the latter, and can be more than 1 V. The barrier height increases, while the work function of the a-Si-Ge-B decreases, as the Ge content of the a-Si-Ge-B increases. It is found that barrier heights estimated by the C-V method are larger than those estimated by the I-V method, and that the difference between the values estimated by the two methods is beyond the extent predicted by existing junction theories. The experimental results are interpreted in accordance with a generalized amorphous-crystalline junction model proposed in this paper.

Yoshihito Amemiya

Papers

Frequency- and temporal-domain neural competition in analog integrate-and-fire neurochips

Current Reference Circuit for Subthreshold CMOS LSIs

A New Planarization Technique for LSI Fabrication Utilizing Si-Ge Film Oxidation

Stochastic resonance among single-electron neurons on Schottky wrap-gate device

Barrier Heights of Junctions between Amorphous Si-Ge-B and Crystalline GaAs