Shunting neural network photodetector arrays in analog CMOS

This paper describes a custom analog CMOS photodetector array IC that exploits nonlinear lateral inhibition to achieve dynamic range compression, edge enhancement, and adaptation to mean input intensity. The neural net array architecture, characterized by nearest-neighbor connections and multiplicative cell interaction, is modeled after biological vision systems. The fabricated IC successfully implements a portion of the compact and powerful nonlinear signal processing performed in the outer layers of the vertebrate retina. Measured results are presented for an optical input intensity range of nearly six decades. A scanning architecture that allows for preferential directional sensitivity is also demonstrated. Measured data agree well with models created using a spreadsheet program     

A process algebraic approach to the specification and analysis ofresource-bound real-time systems

Recently, significant progress has been made in the development of timed process algebras for the specification and analysis of real-time systems. This paper describes a timed process algebra called ACSR, which supports synchronous timed actions and asynchronous instantaneous events. Timed actions are used to represent the usage of resources and to model the passage of time. Events are used to capture synchronization between processes. To be able to specify real systems accurately, ACSR supports a notion of priority that can be used to arbitrate among timed actions competing for the use of resources and among events that are ready for synchronization. The paper also includes a brief overview of other timed process algebras and discusses similarities and differences between them and ACSR     

Approximation of certain functions given by integrals with highlyoscillatory integrands

There is often a need to approximate integrals of highly oscillatory functions when studying scattering and diffraction of electromagnetic waves. This paper presents a method of estimating certain types of these integrals by evaluating one interpolating function and performing one or two relatively easy numerical integrations. The method is demonstrated for the case of a Fresnel integral     

Combined statistical study of joint angles and ground reactionforces using component and multiple correspondence analysis

The purpose of this research is to propose a general methodology to draw gait patterns when including hip, knee and ankle angle excursions in the sagital plane and the three components of the ground reaction force. The multidimensional signal analysis procedure is divided into three main stages: 1) describing the six signals of each step through sliding averages computed for successive time windows, 2) analyzing separately the six step-by-window tables obtained for each signal through principal component analysis to reduce the excessive quantity of data, and 3) analyzing the most informative time windows of the six signals at the same time. To emphasize both linear and nonlinear relationships between the respective time windows, the signal range within a window is cut into fuzzy modalities such as, “low” “medium” and “large.” The resulting table is investigated using multiple correspondence analysis. The outcomes are gait patterns combining both time and space aspects. The factor planes obtained from multiple correspondence analysis constitute initial data models so that new data obtained from pathological gait can be directly projected onto them. Such an operation can be used to show how the rehabilitation of a particular subject evolves in relation to normal gait patterns     

Fundamental quantum 1/f noise in semiconductor devices

The quantum 1/f noise theory has been developed in the last two decades and has been applied to 1/f noise suppression in various electronic devices. This theory derives fundamental quantum fluctuations present in the elementary processes of physics at the level of the quantum mechanical cross sections and process rates. This paper demonstrates the basic simplicity of the theory with an elementary physical derivation followed by a short derivation of the conventional quantum 1/f effect in second quantization, for an arbitrary number of particles N defining the scattered current in the final state. A new derivation of the coherent quantum 1/f effect is also included. No adjustable parameters are present in the quantum 1/f theory. Practical applications to semiconductor materials, p-n junctions, SQUID's and quartz resonators are presented. Optimal design principles based on the quantum 1/f theory are described and explained     

Experiments on hot electron noise in semiconductor materials forhigh-speed devices

Experimental results on noise temperature and spectral density of current fluctuations (electron diffusion) at high electric fields in silicon, gallium arsenide, and indium phosphide are presented. The dominant noise sources are discussed in their relation to electron scattering mechanisms. Physical backgrounds of high speed-low noise performance (noise-speed tradeoff) are considered. Suppression in short samples of the fluctuations having long correlation time constant and (or) high threshold energy is discussed     

Effects of hot carrier induced interface state generation insubmicron LDD MOSFET's

A two-dimensional numerical simulation including a new interface state generation model has been developed to study the performance variation of a LDD MOSFET after a dc voltage stress. The spatial distribution of hot carrier induced interface states is calculated with a breaking silicon-hydrogen bond model. Mobility degradation and reduction of conduction charge due to interface traps are considered. A 0.6 μm LDD MOSFET was fabricated. The drain current degradation and the substrate current variation after a stress were characterized to compare the simulation. A reduction of the substrate current at V_g ≃0.5 V_d in a stressed device was observed from both the measurement and the simulation. Our study reveals that the reduction is attributed to a distance between a maximum channel electric field and generated interface states     

On the hot-carrier-induced post-stress interface trap generation inn-channel MOS transistors

A continued fast interface trap generation is observed in n-channel MOS transistors after termination of the hot-carrier stress. The magnitude of this post-stress effect is strongly dependent on the conditions of the preceding stress, on the post-stress conditions and on the process parameters. For measurements at 293 K, a simple model is proposed which is based on the release of hydrogen by the thermal detrapping of holes, and which can explain the observed dependencies. The importance of the post-stress D_it-generation is illustrated for the case of dynamic stress conditions where it can lead to an apparently deviating degradation behavior     

Measuring efficiency of power plants in Israel by data envelopmentanalysis

An application of data envelopment analysis (DEA) for measuring and evaluating the operating efficiency of power plants in the Israeli Electric Corporation (IEC) is presented. Emphasis is placed on the process of screening the list of potential input and output factors and determining the most relevant ones. Special attention is given to the qualitative factor concerning air pollution, which is treated as a categorical variable. The incorporation of `standard data' is examined and the results are analyzed