[en] The two Coulomb centers problem in a complex plane of an internuclear distance R is considered as a system of the nonlinear equations. The system, which arises at use of a finite-difference method, is solved by the Newton's method with the use of LU-decomposition of the system matrix. At an evaluation of the LU-decomposition and solution of the system the regularization was applied

No abstract available

[en] In the solution of large-scale numerical prob- lems, parallel computing is becoming simultaneously more important and more difficult. The complex organization of today's multiprocessors with several memory hierarchies has forced the scientific programmer to make a choice between simple but unscalable code and scalable but extremely com- plex code that does not port to other architectures. This paper describes how the SMARTS runtime system and the POOMA C++ class library for high-performance scientific computing work together to exploit data parallelism in scientific applications while hiding the details of manag- ing parallelism and data locality from the user. We present innovative algorithms, based on the macro -dataflow model, for detecting data parallelism and efficiently executing data- parallel statements on shared-memory multiprocessors. We also desclibe how these algorithms can be implemented on clusters of SMPS

[en] This paper reports progress on implementing a new capability of adaptive mesh refinement into the Eulerian multimaterial shock- physics code CTH. The adaptivity is block-based with refinement and unrefinement occurring in an isotropic 2:1 manner. The code is designed to run on serial, multiprocessor and massive parallel platforms. An approximate factor of three in memory and performance improvements over comparable resolution non-adaptive calculations has-been demonstrated for a number of problems

[en] The phenomena of transient movements have an wavy character due to the pipe elasticity, inertia and compressibility of the fluid. Disturbances of the boundary conditions would result in local and pressure changes which are further transferred through waves along the whole hydraulic installation. A program based of the method of wave superposition was developed and implemented on PC/386 computers. The program was applied for analysis of water hammer shock effects in the Emergency Core Cooling System at the Nuclear Power Plant Cernavoda

[en] The paper proposes an algorithms to reduce the memory size of look-up tables, when adding and subtracting numbers in the Redundant Logarithmic Number System, which requires voluminous look-up table especially when adding numbers. In the look-up tables are saved only curvature points in the function s_b(z). The point values between two curvature points, required for addition and subtraction, are calculated with a cubic spline interpolation for unequally spaced points. Since the cubic spline interpolation involves a lot of multiplications and divisions, logarithmic arithmetic is used in multiplications and divisions to be implemented easily in hardware. (Author)

[en] In this paper an iterative technique is discussed for finding the algebraic alloy smallest (or largest) eigenvalue of the generalized eigenvalue problem. A-lambda M, where A and M are real, symmetric, and M is positive definite. It is assumed that A and M are such that it is undesirable to factor the matrix A-sigma M for any value of sigma. It is proved that the algorithm is globally convergent, and that convergence is asymptotically quadratic. Finally, the modifications required in the algorithm to make it computationally feasible are discussed

[en] This dissertation describes an implementation of a Relational Data Base Management System on a microcomputer. A specific floppy disk based hardward called TERAK is being used, and high level query interface which is similar to a subset of the SEQUEL language is provided. The system contains sub-systems such as I/O, file management, virtual memory management, query system, B-tree management, scanner, command interpreter, expression compiler, garbage collection, linked list manipulation, disk space management, etc. The software has been implemented to fulfill the following goals: (1) it is highly modularized. (2) The system is physically segmented into 16 logically independent, overlayable segments, in a way such that a minimal amount of memory is needed at execution time. (3) Virtual memory system is simulated that provides the system with seemingly unlimited memory space. (4) A language translator is applied to recognize user requests in the query language. The code generation of this translator generates compact code for the execution of UPDATE, DELETE, and QUERY commands. (5) A complete set of basic functions needed for on-line data base manipulations is provided through the use of a friendly query interface. (6) To eliminate the dependency on the environment (both software and hardware) as much as possible, so that it would be easy to transplant the system to other computers. (7) To simulate each relation as a sequential file. It is intended to be a highly efficient, single user system suited to be used by small or medium sized organizations for, say, administrative purposes. Experiments show that quite satisfying results have indeed been achieved

[en] An error-detection method for serial transmissions is presented that uses an integer arithmetic checksum. The checksum is compared with cyclic-redundancy-check methods with regard to error-detecting ability and efficiency of implementation in software (or firmware). The method is a bit weaker at detection but is more efficient, thus representing a different and potentially useful choice in the cost-benefit spectrum

[en] Aspects of simulation technology are discussed, taking into account microcomputers in simulation, heuristic/adaptive systems, differential equations approaches, available simulation packages, selected operations research applications, and mathematical and statistical tools. Hybrid systems are discussed along with topics of chemical sciences. Subjects related to physical and engineering sciences are explored, giving attention to aeronautics and astronautics, physical processes, nuclear/electrical power technology, advanced computational methods and systems, avionics systems, dynamic systems analysis and control, and industrial systems. Environmental sciences are considered along with biomedical systems, managerial and social sciences, questions of simulation credibility and validation, and energy systems. A description is provided of simulation facilities, and topics related to system engineering and transportation are investigated