A new evolutionary system for evolving artificial neural networks

This paper presents a new evolutionary system, i.e., EPNet, for evolving artificial neural networks (ANNs). The evolutionary algorithm used in EPNet is based on Fogel's evolutionary programming (EP). Unlike most previous studies on evolving ANN's, this paper puts its emphasis on evolving ANN's behaviors. Five mutation operators proposed in EPNet reflect such an emphasis on evolving behaviors. Close behavioral links between parents and their offspring are maintained by various mutations, such as partial training and node splitting. EPNet evolves ANN's architectures and connection weights (including biases) simultaneously in order to reduce the noise in fitness evaluation. The parsimony of evolved ANN's is encouraged by preferring node/connection deletion to addition. EPNet has been tested on a number of benchmark problems in machine learning and ANNs, such as the parity problem, the medical diagnosis problems, the Australian credit card assessment problem, and the Mackey-Glass time series prediction problem. The experimental results show that EPNet can produce very compact ANNs with good generalization ability in comparison with other algorithms.  

A modal logic for message passing processes

A first-order modal logic is given for describing properties of processes which may send and receive values or messages along communication ports. We give two methods for proving that a process enjoys such a property. The first is the construction, for each processP and formulaF, of acharacteristic formula P satF such thatP enjoys the propertyF if and only if the formulaP satF is logically equivalent to tt. The second is a sound and complete proof system whose judgements take the formB P: F, meaning: under the assumptionB the processP enjoys the propertyF.The notion ofsymbolic operational semantics plays a crucial role in the design of both the characteristic formulae and the proof system.This work was been supported by the SERC grant GR/H16537 and the ESPRIT BRA CONCUR II  

Adaptive tracking control of an MEMS gyroscope with H-infinity performance

Microelectromechanical systems (MEMSs) pose unique measurement and control problems compared with conventional ones because of their small size,low cost,and low power consumption.The vibrating gyroscope is one of those MEMS devices that have significant potential in many industry applications.When the MEMS gyroscope system is considered simultaneously with the coupling terms,the exogenous disturbances and the parameter variations,the controller design of this system becomes very challenging.This paper investigates the primary control problem of a perturbed vibrating MEMS gyroscope.A nonlinear robust adaptive control scheme is proposed for the drive axis of a vibrating MEMS gyroscope.By combining the dynamic surface control (DSC) method with the H-infinity disturbance attenuation technique,a simpler systematic design procedure is developed.The derived H-infinity controller has a simplified structure,and it can drive the drive axis to resonance,regulate the output amplitude of the drive axis to a desired value,and attenuate the generalized disturbances.The features of the derived controller are discussed and illustrated by the simulation of a closed-loop system.The analysis and simulation show that the obtained controller possesses good adaptability and robustness to system uncertainties.  

On the model-based approach to nonlinear networked control systems

The problem of model-based stabilization of a nonlinear system based on its approximate discrete-time model is addressed, under the assumption that both the feedforward and the feedback paths are subject to network-induced constraints. These constraints include irregularity of the transfer intervals, time-varying communication delays, and the possibility of packet losses. A communication protocol that copes with these constraints is proposed. A “Stability+performance recovery” result for the nonlinear model-based networked control system (NCS) is formulated and proven.Simulation results presented confirm that the proposed method improves the maximum allowable transfer interval.  

Fingerprint Retrieval for Identification

This paper presents a front-end filtering algorithm for fingerprint identification, which uses orientation field and dominant ridge distance as retrieval features. We propose a new distance measure that better quantifies the similarity evaluation between two orientation fields than the conventional Euclidean and Manhattan distance measures. Furthermore, fingerprints in the data base are clustered to facilitate a fast retrieval process that avoids exhaustive comparisons of an input fingerprint with all fingerprints in the data base. This makes the proposed approach applicable to large databases. Experimental results on the National Institute of Standards and Technology data base-4 show consistent better retrieval performance of the proposed approach compared to other continuous and exclusive fingerprint classification methods as well as minutia-based indexing schemes  

Microheated substrates for patterning cells and controlling development

Here, we seek to control cellular development by devising a means through which cells can be subjected to a microheated environment in standard culture conditions. Numerous techniques have been devised for controlling cellular function and development via manipulation of surface environmental cues at the micro- and nanoscale. It is well understood that temperature plays a significant role in the rate of cellular activities, migratory behavior (thermotaxis), and in some cases, protein expression. Yet, the effects and possible utilization of micrometer-scale temperature fields in cell cultures have not been explored. Toward this end, two types of thermally isolated microheated substrates were designed and fabricated, one with standard backside etching beneath a dielectric film and another with a combination of surface and bulk micromachining and backside etching. The substrates were characterized with infrared microscopy, finite element modeling, scanning electron microscopy, stylus profilometry, and electrothermal calibrations. Neuron culture studies were conducted on these substrates to 1) examine the feasibility of using a microheated environment to achieve patterned cell growth and 2) selectively accelerate neural development on regions less than 100 /spl mu/m wide. Results show that attached neurons, grown on microheated regions set at 37/spl deg/C, extended processes substantially faster than those incubated at 25/spl deg/C on the same substrate. Further, unattached neurons were positioned precisely along the length of the heater filament (operating at 45/spl deg/C) using free convection currents. These preliminary findings indicate that microheated substrates may be used to direct cellular development spatially in a practical manner.  

Stability criteria in terms of two measures for discrete systems

This paper studies stability problems for two kinds of discrete systems in terms of two different measures. The basic idea of this approach is to discuss the qualitative behaviour of a map h along solutions of discrete systems whose initial value are measured by a second map h₀. By doing this, one may deal with, in a unified way, several concepts and associated problems, which are usually considered separately. Stability criteria in terms of two measures are established employing the method of Lyapunov functions and Razumikhin techniques.  

Virtual DesignWorks—designing 3D CAD models via haptic interaction

Haptic devices (force feedback interfaces) show great promise for use in the design of CAD models. However, current haptic systems are used primarily to verify rather than to interact with CAD systems to design a model.The paper discusses a haptic-based CAD system—Virtual DesignWorks. It is the world's first haptic application for the design of CAD models based on component technology (COM+). With haptic devices, the system allows engineers, in virtual space, to directly touch a native B-Rep CAD model, and deform it by pushing, pulling and dragging its surfaces in a natural three-dimensional environment. Virtual DesignWorks adopts the novel COM-based haptic model, which demonstrates significant advantages compared to the traditional haptic models. Force feedback gives designers the greatest flexibility for the design of complex surfaces, and haptics has the potential to become a critical interface for design applications.  

New Grid Scheduling and Rescheduling Methods in the GrADS Project

The goal of the Grid Application Development Software (GrADS) Project is to provide programming tools and an execution environment to ease program development for the Grid. This paper presents recent extensions to the GrADS software framework: a new approach to scheduling workflow computations, applied to a 3-D image reconstruction application; a simple stop/migrate/restart approach to rescheduling Grid applications, applied to a QR factorization benchmark; and a process-swapping approach to rescheduling, applied to an N-body simulation. Experiments validating these methods were carried out on both the GrADS MacroGrid (a small but functional Grid) and the MicroGrid (a controlled emulation of the Grid).  

A control scheme for stable force-reflecting teleoperation over IP networks.

The problem of force-reflecting teleoperation over Internet protocol networks is addressed. The existence of time-varying communication delay and the possibility of data losses are taken into consideration. Since significant data loss may result in discontinuity of the reference trajectory transmitted through the communication channel, the proposed control scheme includes a filter that provides a smooth approximation of a possibly discontinuous reference trajectory. The stability of the overall system is guaranteed by a version of the input-to-output stable small-gain theorem for functional differential equations. If the communication delay in the forward channel is an "approximately smooth" function of time, the proposed scheme guarantees that the slave manipulator tracks the delayed trajectory of the master within a prescribed small error.