Development Of Computational Methods Research Articles

Efficient Task Scheduling Approach Relevant to the Hardware/Software Co-Design of Embedded System

Task scheduling is the primary multitasking activity controlled by the real-time executive. As hardware/software co-design of embedded systems has been enabled by advances in computer technologies, reprogrammable hardware can be used to implement a co-processor to perform most of the kernel functions, including task scheduling. In this kind of system design, more complex scheduling approaches can be applied. In this paper, a complex scheduling approach, which takes into account advantages of evolutionary computation (i.e., neurocomputing and genetic search and optimization) is presented. First, we present a model based on the Hopfield-Tank neural network (11). Then, we introduce modifications of the method based on the network model to improve the quality of the solutions. Finally, we propose a mixed approach of this evolutionary computation method and an extension of the Earliest Deadline First approach (3) for scheduling both types of periodic and aperiodic tasks. We also discuss simulation results that demonstrate performance that could be obtained by using this approach.

LEARNABLE EVOLUTION MODEL: Evolutionary Processes Guided by Machine Learning

A new class of evolutionary computation processes is presented, called Learnable Evolution Model or LEM. In contrast to Darwinian-type evolution that relies on mutation, recombination, and selection operators, LEM employs machine learning to generate new populations. Specifically, in Machine Learning mode, a learning system seeks reasons why certain individuals in a population (or a collection of past populations) are superior to others in performing a designated class of tasks. These reasons, expressed as inductive hypotheses, are used to generate new populations. A remarkable property of LEM is that it is capable of quantum leaps (“insight jumps”) of the fitness function, unlike Darwinian-type evolution that typically proceeds through numerous slight improvements. In our early experimental studies, LEM significantly outperformed evolutionary computation methods used in the experiments, sometimes achieving speed-ups of two or more orders of magnitude in terms of the number of evolutionary steps. LEM has a potential for a wide range of applications, in particular, in such domains as complex optimization or search problems, engineering design, drug design, evolvable hardware, software engineering, economics, data mining, and automatic programming.

Development of electrodynamic methods for calculation of printed dipole antennas based on multilayer dielectric structures

We found a solution for the electrodynamic problem of calculating the main characteristics (input resistance, radiation pattern, and directive gain) of a printed dipole radiator located in a no-loss multilayer dielectric structure (MDS).

Using neural networks and genetic algorithms to enhance performance in an electronic nose.

Sensitivity, repeatability, and discernment are three major issues in any classification problem. In this study, an electronic nose with an array of 32 sensors was used to classify a range of odorous substances. The collective time response of the sensor array was first partitioned into four time segments, using four smooth time-windowing functions. The dimension of the data associated with each time segment was then reduced by applying the Karhunen-Loéve (truncated) expansion (KLE). An ensemble of the reduced data patterns was then used to train a neural network (NN) using the Levenberg-Marquardt (LM) learning method. A genetic algorithm (GA)-based evolutionary computation method was used to devise the appropriate NN training parameters, as well as the effective database partitions/features. Finally, it was shown that a GA-supervised NN system (GANN) outperforms the NN-only classifier, for the classes of the odorants investigated in this study (fragrances, hog farm air, and soft beverages).

Applying Vibrational Potential Method to Shop Scheduling Problems

Many deterministic computational methods have addressed flow and job shop scheduling - both being highly representative, critical problems. Such methods become obsolete due to solution time and difficulty due to problem size. Evolutionary computation appears feasible for overcoming these problems because it can handle large problems, but at the expense of closeness to optimal solutions. This paper partially compares the two problems based on evolutionary computational method, the vibrational potential method (VPM). To compare this to the performance of older methods, genetic algorithms (GAs) are used in the shop flow domain. This paper outlines VPM features in scheduling showing new advantages in problem formulation and solution.

The applications of evolutionary computation in software reliability

Software reliability models(SRMs) are the theoretic foundation of software reliability. However, the existence of intrinsic limitation of the preposition in traditional model building confirnes the applications of SRMs. In this paper, a new method evolutionary computation, is used to estimate parameters of SRMs. At the same time, new algorithms are also proposed and employed to build SRMs. As the experiment results demonstrate, evolutionary computation method is poweful and effective.

Étude des phénomènes de transferts thermiques dans les stérilisateurs à vapeur

Study of heat transfer phenomena in a vapor sterilizer. Steam sterilization occupies a preferential place in the hospital hygiene. Hospital infection designates any sickness contracted in a hospital, allocated to microorganisms which affected sick people or hospital staff. The research work aims at studying heat transfer phenomena in a vapor sterilizer. The interactions between the different modes of heat transfer confer great complexity to this problem. The development of calculation method, zonal method, allowed to predict the field of temperature and heat transfer to optimise vapor sterilizers. This work presents the results of experiments carried out on a cycle of instrument sterilization. The main motivations of this study are the droplets of water which remain pasted to the load at the end of the drying process.

Special Article of Chaos, Self-Organized System

The actual environments under which robots are going to operate from now on are complex and sometimes unstable unlike the arranged environments in factories. It is becoming increasingly necessary for the robots to be able to cope with complexities by maintaining a symbiotic relationship with man who are behaving in mental world in various manners and life styles. This is not a task for the distant future but has already been posing daily problems in the fields of computer information communications that reach an international networked society. In this world, there is already a limitation to top-down controls based on hierarchical knowledge and guidance instructions. Rather, the situations indicate that this world should be taken as a complex adaptive system that requires recognition of the environments based on an autonomy of the system, adaptation and learning by behavior, and formation of orders according to self-organization, through a bottom-up approach. This is a considerable task to be tackled from now on if it is desired that robots are to play an active role in various parts of society in the near future. In considering this problem, it is important to learn from nature, ecological systems, and life systems. In recent years, new academic research fields have been generated that imitate the information processing functions of creatures such as recognition, evolution and adaptation, then reproduce these information processing functions in CG's and robots, and apply them to science and technology. This has been posing large topics relating to the autonomy, adaptation, learning and evolution of complex systems and finally to the creativity of a living body system. The key concept in this case is a chaos edge system called by Langton. In a complex system like a life, there is a self-organization marginal level of a certain scale, above which information is scattered, and below which information is fixed like a crystal. An integration is progressed and emerged in these systems. This characteristic is called the chaos edge system. Along with the outbreak of research in this new field, this has given substantial influence to the research into conventional fuzzy theories, neural networks, and intelligence systems such as artificial brains. Furthermore, along with the development of calculation methods called genetic algorithms which have been learned from the adaptive evolution of creatures, chaos, fuzzy, neuro, AI and GA are all directed towards the structuring of a new intelligent system. We cannot take our attention off the research in this new field. In order for robots to maintain a symbiotic relationship with man in daily life, the new development relating to the complexities of the creatures as described above is necessary. We already open every year an intelligent system symposium which aims at the merging and new developments of fuzzy, neuro and AI. At last year's FAN'95, we opened an organized session whose theme was chaos and self-organization systems. This special article has been organized now to high-light the papers announced at this OS.It has been possible to take up a wide range of issues including ecological systems, living systems, chaos, robots and the mind. I would like to express my thanks to those who have found time in their busy lives to contributed their papers to this special article . There are many more papers that were presented at the symposium and only a function of them were included in this article because of the limitation of space. I look forward to organizing a similar article again for this book, and it will be my great pleasure if readers can understand the latest situation of the research in this field from this issue. Finally, my thanks are also due to Dr. Tetsuro Yabuta (NTT) and Dr. Tadashi Iokibe (Meidensha) who helped in editing this article.

Evolutionary programming IV: Proceedings of the fourth annual conference on evolutionary programming

From the Publisher: March 1-3, 1995, San Diego, California Evolutionary programming is one of the predominate algorithms withing the rapidly expanding field of evolutionary computation. These edited contributions to the Fourth Annual Conference on Evolutionary Programming are by leading scientists from academia, industry, and defense. The papers describe both the theory and practical application of evolutionary programming, as well as other methods of evolutionary computation including evolution strategies, genetic algorithms, genetic programming, and cultural algorithms. Topics include: Novel Areas of Evolutionary Programming and Evolution Strategies. Evolutionary Computation with Medical Applications. Issues in Evolutionary Optimization Pattern Discovery, Pattern Recognition, and System Identification. Hierarchical Levels of Learning. Self-Adaptation in Evolutionary Computation. Morphogenic Evolutionary Computation. Issues in Evolutionary Optimization. Evolutionary Applications to VLSI and Part Placement. Applications of Evolutionary Computation to Biology and Biochemistry Control. Applications of Evolutionary Computation. Genetic and Inductive Logic Programming. Genetic Neural Networks. The Future of Evolutionary Computation. A Bradford Book. Complex Adaptive Systems series

A Comparison of Evolutionary Programming and Genetic Algorithms on Selected Constrained Optimization Problems

Evolutionary programming and genetic algorithms are compared on two constrained optimization problems. The constrained problems are redesigned as related unconstrained problems by the application of penalty functions. The experiments indicate that evolutionary programming outperforms the genetic algorithm. The results are statistically significant under nonparametric hypothesis testing. The results also indicate potential difficulties in the design of suitable penalty functions for constrained optimization problems. A discussion is offered regarding the suitability of different methods of evolutionary computation for such problems.

Non-standard methods in evolutionary computation

The paper presents non-standard methods in evolutionary computation and discusses their applicability to various optimization problems. These methods maintain populations of individuals with nonlinear chromosomal structure and use ‘genetic’ operators enhanced by the problem specific knowledge.

Development of Calculation Method of B-10 Concentration in Heavy Water for FUGEN

Abstract Reactivity control of the Fugen Nuclear Power Station is performed by the control rods and the adjustment of the concentration of 10B dissolved in the heavy water as boric acid. An accurate evaluation of the 10B concentration in the heavy water is important in order to determine the excess reactivity. It has been a conventional method to sample the heavy water and measure the 10B concentration in it directly, which is time- and labor-consuming and. moreover, costly. We have developed an economical and expedient calculation method to determine the 10B concentrations in the heavy water. This method uses a model of boric acid injection, boric acid removal, poison burning in the core and heavy water purification system. The calculation result has been evaluated by the comparison of calculated 10B concentrations with the data obtained by mass spectrometry method, and the calculation accuracy is approximately ±0.1 ppm. This calculation program is practical and successfully in use now.

Life-expectancy formulas based on the load model

Reduction in life expectancy is already used as a supplementary measure of radiation safety and has been widely investigated in radiological experiments. Usually, the median or the mean life expetancy calculated form the onset of radiation exposure has been considered. Considerable data on the dependence of the reduction in median and mean life expectancy on the dose in different exposure conditions has now been accumulated. The development of calculation methods for different exposure conditions would facilitate the generalization of these and other data characterizing the change in lifetime under the action of ionizing radiation and their wider use in estimating radiation safety. A mathematical model of cohort extinction in normal conditions and in unfavorable circumstances (henceforward called the load model of mortality) that is in satisfactory agreement with observational data has been previously proposed. The aim of the present work is to obtain expressions for the median and mean life expectancy on the basis of this model. Formulas for the radiational load and age at the onset of irradiation and their relationship are derived for low levels of radiation. Particular attention is paid to short- and long-term radiation exposure.

Mathematical modeling of low-frequency electromagnetic fields in a three-dimensional medium

Further development of the methods of electromagnetic prospecting of mineral deposits essentially depends on mathematical modeling of electromagnetic fields in nonhomogeneous media. This necessitates the development of methods for calculation of electromagnetic fields with sufficiently complex models of the medium and the source. The development of the integral equation method and the finite-difference method tbr two-dimensional problems was virtually completed by the end of the 1970s. In recent years, these methods have begun to be used in three-dimensional modeling. However, in the threedimensional case, the efficiency of the finite-difference method is not competitive with that of the integral equation method. The main ideas of the integral equation method for three-dimensional problems are described in [1-3]. The most complete discussion of the theory of integral equations in boundary-value problems of electrodynamics and theoretical justification of the integral equation method can be found in [4]. Initially, the integral equation method was applied to the model of a half-space with a nonhomogeneous inclusion. In [5], an algorithm is proposed for calculating the electromagnetic field in a layered medium with a nonhomogeneous inclusion in any layer. The method is further developed in [6, 7]. Some additional possibilities of efficient use of machine time and memory, which is a highly relevant factor for the solution of three-dimensional problems, are suggested in [7]. The integral equation method thus has reached a sufficiently high level of development and can be used for detailed numerical analysis of anomalous fields and local ore bodies. It also provides a technique for the development of interpretation methods for various problems of electrical ore prospecting. In this paper, we generalize the electrical prospecting problem to the case when the body is located in several layers. The results make it possible to analyze the effect of subsurface inclusions that frequently occur in the first layer or changes of the layer boundary. We also propose a more general method of solving the integral equation and examine examples of numerical calculations for various media. Consider a three-dimensional body with conductivity oh(x, y, z) located arbitrarily in a layered medium with conductivity am(Z). Above the medium, at z > 0, extends a half-space (air) with conductivity a o = 0. The medium is magnetically homogeneous, i.e., the magnetic permeability of the medium is constant and equal to the magnetic permeability of the vacuum (/z = /Jo)- The time dependence is taken in the form exp(-ka). The expressions for the electromagnetic field at any point in the layered medium have the form [6]

Development of Calculation Method of B-10 Concentration in Heavy Water for FUGEN

Development of Calculation Method of B-10 Concentration in Heavy Water for FUGEN

Development of calculation methods for the design of structural fire protection

In this country, as well as in most others, the level of structural fire protection is set by the regulatory authorities, in terms of a specified fire resistance period. The engineer must demonstrate that each element of structure would survive for the required period if it were subjected to the standard fire resistance test of BS476. This is normally demonstrated by using tabular data, such as the deemed‐to‐satisfy tables in the Building Regulations, or by obtaining a report of a test of a replica of the particular element.

Turbulence Measurements Near the Stern of a Ship Model

An experimental investigation in which Reynolds stress profiles were measured in the thick three-dimensional turbulent boundary layer at the stern of a ship model has been carried out. The measurements were performed using a specially developed hot-wire technique in which the mean velocity component perpendicular to the surface was considered. A large number of results are given in diagrams, and an error estimation for the different Reynolds stresses is presented. Efforts have been made, when positioning the measured turbulence profiles, to enable future development of calculation methods based on these results. The measured profiles have revealed a strong influence of streamline convergence (divergence) on the Reynolds stresses. Also, the effects of wall curvature are of importance, and since most parts of the investigated region have a convex curvature the average level of the stresses is reduced.

Development of calculation method for ac resistance of power cable conductors with individually insulated strands

Development of calculation method for ac resistance of power cable conductors with individually insulated strands

Measurements and Calculations of the Isothermal Flow in Axisymmetric Models of Combustor Geometries

Measurements with laser-Doppler anemometry and calculations with finite-difference solutions of the time-averaged Navier-Stokes equations and a two-equation turbulence model, have been obtained for the turbulent isothermal flow in an axisymmetric geometry related to gas-turbine combustors. The results quantify the flow patterns in the arrangement and demonstrate the extent to which they can be represented by calculation. The discrepancies between measured and calculated results are shown to depend more on the distribution of grid nodes than on the turbulence model. Even with a distribution of nodes which is considered to be near optimum, differences between measurement and calculation exist and are particularly significant in the regions of steep velocity gradient immediately downstream of the incoming annular jet. The general trends are, however, correctly represented, and the calculation method has been used to determine the influence of the width of the annulus and of the jet gap. The results provide information of relevance to the development of calculation methods for real combustors, and this is discussed.

Recent Developments in Calculation Methods for Turbulent Boundary Layers With Pressure Gradients and Heat Transfer

A review is given of the recent development in turbulent boundary layers. At first, for the case of incompressible flow, the variation of the shape of velocity profile with the pressure gradient is discussed; also the temperature distribution and heat transfer in incompressible boundary layers are treated. Finally, problems of the turbulent boundary layer in compressible flow are considered.