COOPT — a software package for optimal control of large-scale differential–algebraic equation systems

This paper describes the functionality and implementation of COOPT. This software package implements a direct method with modified multiple shooting type techniques for solving optimal control problems of large-scale differential–algebraic equation (DAE) systems. The basic approach in COOPT is to divide the original time interval into multiple shooting intervals, with the DAEs solved numerically on the subintervals at each optimization iteration. Continuity constraints are imposed across the subintervals. The resulting optimization problem is solved by sparse sequential quadratic programming (SQP) methods. Partial derivative matrices needed for the optimization are generated by DAE sensitivity software. The sensitivity equations to be solved are generated via automatic differentiation.COOPT has been successfully used in solving optimal control problems arising from a wide variety of applications, such as chemical vapor deposition of superconducting thin films, spacecraft trajectory design and contingency/recovery problems, and computation of cell traction forces in tissue engineering.     

CATPAC—An interactive software package for control system design

This report describes a dialogue-oriented software package for computer-aided engineering in control instrumentation. It comprises programmed algorithms for process identification, analysis, simulation, and controller design. For this package a novel architecture was developed to enable a user-friendly interactive application of algorithms. The special structure of the system supports the archiving of computed results, and it facilitates the selection of suitable methods by providing interactive aids.     

SA3—a tool for supporting adaptable software architecture generation for embedded systems

Adaptability is emerging as an important attribute or nonfunctional requirement (NFR) for embedded systems. Intuitively, adaptability is the ability of a software system to accommodate changes in its environment. However, in order for the embedded system to be adaptable its architecture, the first step in the development, should itself be adaptable. It will be helpful if the generation of this architecture could be automated. In this paper, we describe a tool called the Software Architecture Adaptability Assistant (SA³) that helps generate adaptable architectures. SA³ uses the properties of the NFR Framework, in particular its knowledge base properties, to create a catalog of various constituents of architecture such as components and connections, and then searches the catalog to find adaptable constituents for the architecture. In this paper, we describe the theory behind SA³ and then describe the tool itself. We then demonstrate the architecture generation capability of the tool for embedded systems. We also discuss why these architectures are adaptable as well as point out directions for further improvement.     

WindStation—a software for the simulation of atmospheric flows over complex topography

The present paper describes a software system aimed at the simulation of the wind field over complex topography. Two different models are implemented. Both these models predict wind speed and direction based on local measurements made with meteo stations. The whole system was developed under a graphical interface, aiming at a better ease of use and output readability. This paper describes the mathematical models employed and provides an overview of the graphical interface. Simulation results are compared with experimental data for an isolated hill and two situations of complex topography.     

π-schemas — a language for graphic representation of algorithms

The paper describes a language for graphic representation of algorithms based on the graph of a hierarchical structure. The main algorithmic constructs of the language are "sequence," "parallel," "select," "loop," and "substitution."Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 93–107, March–April, 1992.     

KINAL—a program package for kinetic analysis of reaction mechanisms

A program package is provided for analysis of kinetic mechanisms on personal computers. KINAL consists of four programs called DIFF, SENS, PROC and YRED. These require similar input data and use common subroutines. DIFF solves stiff differential equations and SENS computes the local concentration sensitivity matrix. PROC generates the rate sensitivity matrix or the quasi-stationary sensitivity matrix from concentration data or uses a matrix computed by SENS and extracts the kinetic information inherent in sensitivity matrices by principal component analysis. Finally, YRED provides suggestions for the elimination of species from the reaction mechanism.     

Automatic generation of fast algorithms for matrix–vector multiplication

This paper describes the methods for finding fast algorithms for computing matrix–vector products including the procedures based on the block-structured matrices. The proposed methods involve an analysis of the structural properties of matrices. The presented approaches are based on the well-known optimization techniques: the simulated annealing and the hill-climbing algorithm along with its several extensions. The main idea of the proposed methods consists in finding a decomposition of the original matrix into a sparse matrix and a matrix corresponding to an appropriate block-structured pattern. The main criterion for optimizing is a reduction of the computational cost. The methods presented in this paper can be successfully implemented in many digital signal processing tasks.     

DNA algorithms for fractal construction—an application of the SInsDelP system

The SInsDelP system with single contextual insertion and (u, v)-contextual deletion was introduced by Murugan and Easwarakumar. In this paper we discuss an application of the SInsDelP system for the construction of fractal images. The fractal images considered are of self-similar types, such as Koch Snowflake, Anti-Koch Snowflake, Fractal Tree and Sierpinski Triangle. This is performed in two stages. A DNA sequence for the fractal image is generated first by a sequence of SInsDelP operations, and then the respective image is produced through the specialized recognition algorithm.     

Formation optimization for a fleet of wheeled mobile robots — A geometric approach

Tight formation-based operations are critical in several emerging applications for robot collectives — ranging from cooperative payload transport to synchronized distributed data-collection. In this paper, we investigate the optimal relative layout for members of a team of Differentially-Driven Wheeled Mobile Robots (DD-WMRs) moving in formation for ultimate deployment in cooperative payload transport tasks.Our particular focus is on modeling such formations, developing the motion plans and determining the “best formation” in a differential-geometric setting. Specifically, a preferred team-fixed frame serves as a virtual leader inducing motion plans for the individual DD-WMRs which form the vertices of a virtual structure. The resulting motion plans for the DD-WMRs as well as overall team-performance depend both on the specifiedteam-frame motions as well as their relative-layout within the formation.Emphasis is placed on developing suitable invariant (yet quantitative) measures of formation quality and a systematic optimization-based selection of the formation-layout. The use of relative formation-parameterization with respect to a team-frame serves to decouple the team-level optimal layout selection process. The optimal location of each DD-WMR can now be found with respect to the team-frame individually and the feasibility of distributed implementation facilitates scaling to larger-sized formations. Analytical and numerical results, from case studies of formation optimization of three DD-WMRs maneuvering along certain desired planar paths, are presented to highlight the salient features and benefits.     

Optimisation of the weighting functions of an H ∞ controller using genetic algorithms and structured genetic algorithms

In this article, the optimisation of the weighting functions for an H _∞ controller using genetic algorithms and structured genetic algorithms is considered. The choice of the weighting functions is one of the key steps in the design of an H _∞ controller. The performance of the controller depends on these weighting functions since poorly chosen weighting functions will provide a poor controller. One approach that can solve this problem is the use of evolutionary techniques to tune the weighting parameters. The article presents the improved performance of structured genetic algorithms over conventional genetic algorithms and how this technique can assist with the identification of appropriate weighting functions’ orders.     

Raising the standard—System-independent programming for educational software

This paper introduces the need for a hardware— and operating system—independent programming environment for educational software production. The proposed system is based upon the graphics library developed at ILECC using the GKS standard. As a result of adopting such a standard developers can expect to achieve software portability, and avoid the problems that were encountered when moving from 8 to 16 bit microcomputers.     

RRtools—a Maple package for aiding the discovery and proof of finite Rogers–Ramanujan type identities

The purpose of this paper is to introduce the RRtools and recpf Maple packages which were developed by the author to assist in the discovery and proof of finitizations of identities of the Rogers–Ramanujan type.     

Teaching about the electricity supply industry—The development and evaluation of a computer based teaching package for schools

This paper describes the development of a computer based teaching package for use at upper secondary school level. The project was funded by Understanding Electricity, which is the educational service of the Electricity Council. The principles of electricity supply are integral to several subject areas in the school curriculum. The purpose of this package is firstly to provide well-resourced teaching material to cover these curriculum needs and secondly to provide an industrial context in which to apply the technical skills acquired in individual subject disciplines. The package is based on a computer simulation that enables the user to experience the problems of running an electricity supply system. The use of the computer in this way enables a powerful investigative approach to be adopted in the classroom.The paper begins by discussing the background to joint industry/education projects and the procedural models that have emerged. It continues by presenting the project history, the development team model used and the educational concepts of electricity supply that provide the background to the computer simulation. Attention is drawn to the ways in which the finished package matches the industrial resource material to curriculum needs.Teachers were involved from the beginning, both in the development of the computer software and in the production of curriculum material. They also undertook the design of investigations in specific subject areas—economics, physics, mathematics and geography. This paper presents the results of field trials and discusses the problems of evaluating and marketing educational material.Although the detail of this paper deals specifically with educational material developed for the Electricity Council, the principles discussed have significance for approaches to the production of educational software generally.     

Design of moiré-free metal meshes using ray tracing for touch screen panels

Using a ray tracing technique, we investigate the dependence of the moiré effect on the crossing angles between touch screen panels (TSPs) and display panels, the metal grid structures (spacing and width), and metal grid shapes (non-uniform and random grids). Of those design parameters, adjusting the crossing angle (∼45°), reducing the grid width (∼1 μm), and employing a random grid in the shape of irregular hexagon are found to suppress the moiré phenomenon to a great extent. We also provide the simulation scheme that can capture the moiré patterns observed experimentally and useful design guidelines for metal grids.     

Local equivalences of distances between clusterings—a geometric perspective

In comparing clusterings, several different distances and indices are in use. We prove that the Misclassification Error distance, the Hamming distance (equivalent to the unadjusted Rand index), and the χ ² distance between partitions are equivalent in the neighborhood of 0. In other words, if two partitions are very similar, then one distance defines upper and lower bounds on the other and viceversa. The proofs are geometric and rely on the concavity of the distances. The geometric intuitions themselves advance the understanding of the space of all clusterings. To our knowledge, this is the first result of its kind.     

A CPU–GPU framework for optimizing the quality of large meshes

The automatic generation of 3D finite element meshes (FEM) is still a bottleneck for the simulation of large fluid dynamic problems. Although today there are several algorithms that can generate good meshes without user intervention, in cases where the geometry changes during the calculation and thousands of meshes must be constructed, the computational cost of this process can exceed the cost of the FEM. There has been a lot of work in FEM parallelization and the algorithms work well in different parallel architectures, but at present there has not been much success in the parallelization of mesh generation methods. This paper will present a massive parallelization scheme for re-meshing with tetrahedral elements using the local modification algorithm. This method is frequently used to improve the quality of elements once the mesh has been generated, but we will show it can also be applied as a regeneration process, starting with the distorted and invalid mesh of the previous step. The parallelization is carried out using OpenCL and OpenMP in order to test the method in a multiple CPU architecture and also in Graphics Processing Units (GPUs). Finally we present the speedup and quality results obtained in meshes with hundreds of thousands of elements and different parallel APIs.     

Conditions of the correctness for the algebra of estimates calculation algorithms with μ-operators over a set of binary-data recognition problems

This paper is aimed to show that specialized neural networks can be useful for finding exact solutions of the recognition problems involving binary data. For this purpose, as an original subclass, we take the subclass of estimates calculation algorithms (ECAs) in which all algorithms correspond to three-level multilayer neural networks (μ-blocks). The correctness conditions are defined that allow a correct algorithm to be constructed in the algebra over this ECA subclass for each Ω-regular recognition problem. This approach does not require additional constraints, except for a trivial one, on the system of ECA support sets.