Is Spiking Logic the Route to Memristor-Based Computers?

Memristors have been suggested as a novel route to neuromorphic computing based on the similarity between neurons (synapses and ion pumps) and memristors. The D.C. action of the memristor is a current spike, which we think will be fruitful for building memristor computers. In this paper, we introduce 4 different logical assignations to implement sequential logic in the memristor and introduce the physical rules, summation, `bounce-back', directionality and `diminishing returns', elucidated from our investigations. We then demonstrate how memristor sequential logic works by instantiating a NOT gate, an AND gate and a Full Adder with a single memristor. The Full Adder makes use of the memristor's memory to add three binary values together and outputs the value, the carry digit and even the order they were input in.Comment: Conference paper. Work also reported in US patent: `Logic device and method of performing a logical operation', patent application no. 14/089,191 (November 25, 2013

Reduction of Observable Robbery and Larceny-Theft in the Twelve Largest Cities in the United States from 1980 to 2009

The reduction in crime rates that occurred in large cities across the United States (US) over the course of the past two decades has been the subject of much speculation and research. However, there have been no definitive empirical studies that conclusively determine the causes for this phenomenon. The goal of this study is to identify the impact of certain factors to the reduction of crime in large US cities that occurred over the past two decades by examining data over a thirty-year period (1980-2009). The identification of contributing factors may allow government officials, both on a local and national level, to focus their efforts on the implementation of policies that, based on empirical study, are likely to reduce crime. This study focuses on Observable Crime, which is operationalized as robberies and larcenies reported in the Uniform Crime Report (UCR) Part II Offenses that were likely to be visible to the police. Those crimes likely to be visible police are determined to be all robberies that were not committed in residences and larcenies that were committed in public areas excluding stores. Law enforcement strategies that were examined in this study include Quality of Life (QOL) Enforcement and Police Presence, which is operationalized as arrests for drug offenses as reported in UCR Part II Arrests and Police Officers per 100,000 residents as reported in the UCR, respectively. The findings of this research supports the hypothesis that Quality of Life Enforcement significant in reducing crime in the twelve largest US cities from 1980-2009

Beyond Markov Chains, Towards Adaptive Memristor Network-based Music Generation

We undertook a study of the use of a memristor network for music generation, making use of the memristor's memory to go beyond the Markov hypothesis. Seed transition matrices are created and populated using memristor equations, and which are shown to generate musical melodies and change in style over time as a result of feedback into the transition matrix. The spiking properties of simple memristor networks are demonstrated and discussed with reference to applications of music making. The limitations of simulating composing memristor networks in von Neumann hardware is discussed and a hardware solution based on physical memristor properties is presented.Comment: 22 pages, 13 pages, conference pape

On computing in fine-grained compartmentalised Belousov-Zhabotinsky medium

We introduce results of computer experiments on information processing in a hexagonal array of vesicles filled with Belousov-Zhabotinsky (BZ) solution in a sub-excitable mode. We represent values of Boolean variables by excitation wave-fragments and implement basic logical gates by colliding the wave-fragments. We show that a vesicle filled with BZ mixture can implement a range of basic logical functions. We cascade BZ-vesicle logical gates into arithmetic circuits implementing addition of two one-bit binary numbers. We envisage that our theoretical results will be applied in chemical laboratory designs of massive-parallel computers based on fine-grained compartmentalisation of excitable chemical systems

The Short-term Memory (D.C. Response) of the Memristor Demonstrates the Causes of the Memristor Frequency Effect

A memristor is often identified by showing its distinctive pinched hysteresis curve and testing for the effect of frequency. The hysteresis size should relate to frequency and shrink to zero as the frequency approaches infinity. Although mathematically understood, the material causes for this are not well known. The d.c. response of the memristor is a decaying curve with its own timescale. We show via mathematical reasoning that this decaying curve when transformed to a.c. leads to the frequency effect by considering a descretized curve. We then demonstrate the validity of this approach with experimental data from two different types of memristors.Comment: Conference paper, to appear in CASFEST 2014 June, Melbourn

Vesicle computers: Approximating Voronoi diagram on Voronoi automata

Irregular arrangements of vesicles filled with excitable and precipitating chemical systems are imitated by Voronoi automata --- finite-state machines defined on a planar Voronoi diagram. Every Voronoi cell takes four states: resting, excited, refractory and precipitate. A resting cell excites if it has at least one excited neighbour; the cell precipitates if a ratio of excited cells in its neighbourhood to its number of neighbours exceed certain threshold. To approximate a Voronoi diagram on Voronoi automata we project a planar set onto automaton lattice, thus cells corresponding to data-points are excited. Excitation waves propagate across the Voronoi automaton, interact with each other and form precipitate in result of the interaction. Configuration of precipitate represents edges of approximated Voronoi diagram. We discover relation between quality of Voronoi diagram approximation and precipitation threshold, and demonstrate feasibility of our model in approximation Voronoi diagram of arbitrary-shaped objects and a skeleton of a planar shape.Comment: Chaos, Solitons & Fractals (2011), in pres