Phase stability diagram program for personal computers

Phase stability diagrams (PSD's) have become widely used in the analysis of metallurgical problems. As manual construction of these diagrams is very time consuming, many computer programs have been developed to perform this task.A new algorithm is described for the construction of PSD's. After specification of all of the possible components to be considered for the desired diagram, the component to be plotted on the x and y axes and the temperature, the balanced equations for all of the possible three condensed phase equilibria are created. The coordinates for the points on the PSD which represent three condensed phase equilbrium are then calculated. Finally, the “stable” three condensed phase equilibria points and the correct order for their connection are established, and the resulting diagram constructed and presented. The FORTRAN program which performs the above calculations runs on an IBM-PC and is very fast and user-friendly. Several examples of its use are presented.     

A pascal program suitable to solve large sparse linear systems on personal computers

Large and very sparse linear systems are common in many real problems, such as those involving electrical networks, structural analyses, power distribution systems, nuclear reactor and operational research. In this paper a Pascal program suitable to solve such a kind of problem is given. The program is tailored to be used on personal computers. The code is based on the classical Gauss-Seidel iterative method.     

基于快速鲁棒特征的CamShift跟踪算法

为了解决CamShift算法由于对颜色敏感导致的跟踪效果变差或失效的问题,提出一种基于局部特征匹配的CamShift跟踪算法。采用快速鲁棒特征(SURF)方法在多通道图像的目标区域和搜索区域提取包含图像信息的局部特征点,并利用近似最近邻搜索对特征点进行匹配;使用提纯后的匹配结果得到特征点的位置、尺度及方向信息,对CamShift方法进行约束和更新,以提高跟踪精度和稳定性。实验结果表明,与经典CamShift算法和同类的改进算法相比,该算法能够较好地实现对复杂背景下旋转和放缩运动目标的实时跟踪。     

Sorting with near linear speed-up on tightly coupled multiprocessors

A new parallel sorting algorithm, called parsort, suitable for implementation on tightly coupled multiprocessors is presented. The algorithm is based upon quicksort and two-way merging. An asynchronous parallel partitioning algorithm is used to distribute work evenly during merging to ensure a good load balance amongst processors, which is crucial if we are to achieve high efficiency. The implementation of this parallel sorting algorithm exhibits theoretical and measured near linear speed-up when compared to sequential quicksort. This is illustrated by the results of experiments carried out on the Sequent Balance 8000 multiprocessor.     

Scheduling on two identical machines with a speed-up resource

We address a variant of scheduling problem on two identical machines, where we are given an additional speed-up resource. If a job uses the resource, its processing time may decrease. However, at any time the resource can only be used by at most one job. The objective is to minimize the makespan. For the offline version, we present an FPTAS. For the online version where jobs arrive over list, we propose an online algorithm with competitive ratio of 1.781, and show a lower bound of 1.686 for any online algorithm.     

Turbomachinery CFD on parallel computers

The role of multistage turbomachinery simulation in the development of propulsion system models is discussed. Particularly, the need for simulations with higher fidelity and faster turnaround time is highlighted. It is shown how such fast simulations can be used in engineering-oriented environments. The use of parallel processing to achieve the required turnaround times is discussed. Current work by several researchers in this area is summarized, as well as efforts at the NASA Lewis Research Center. The latter efforts are focused on implementing the average-passage turbomachinery model on MIMD, distributed memory parallel computers. Performance results are given for inviscid, single blade row and viscous, multistage applications on several parallel computers, including networked workstations.     

Industrial simulation on parallel computers

Parallel computers have demonstrated their principle suitability for numerical simulation during the eighties and early nineties. In particular, they were able to provide a cost-effective means of achieving high performance computing (HPC) power. Even so, there was only a limited impact of this technology on industrial computing. In order to foster the take-up of this technology by industrial users, the European Commission launched a number of projects as part of the Esprit programme to parallelize commercial application programs, to demonstrate, document and disseminate the benefits of parallel architectures, and to explore the potential of parallel simulation in new application areas. Large-scale technology transfer initiatives such as Europort,¹ Europort-D and Preparatory Support and Transfer Programme (PST) aimed at helping the industry in Europe to exploit the benefits of HPC, based on parallel computing, thus increasing their competitiveness. This paper gives a review on major activities and highlights their impact on industry by means of some selected examples.     

Algorithms on ensemble quantum computers

In ensemble (or bulk) quantum computation, all computations are performed on an ensemble of computers rather than on a single computer. Measurements of qubits in an individual computer cannot be performed; instead, only expectation values (over the complete ensemble of computers) can be measured. As a result of this limitation on the model of computation, many algorithms cannot be processed directly on such computers, and must be modified, as the common strategy of delaying the measurements usually does not resolve this ensemble-measurement problem. Here we present several new strategies for resolving this problem. Based on these strategies we provide new versions of some of the most important quantum algorithms, versions that are suitable for implementing on ensemble quantum computers, e.g., on liquid NMR quantum computers. These algorithms are Shor’s factorization algorithm, Grover’s search algorithm (with several marked items), and an algorithm for quantum fault-tolerant computation. The first two algorithms are simply modified using a randomizing and a sorting strategies. For the last algorithm, we develop a classical-quantum hybrid strategy for removing measurements. We use it to present a novel quantum fault-tolerant scheme. More explicitly, we present schemes for fault-tolerant measurement-free implementation of Toffoli and s_z^1/4,\sigma_{z}^{1/4}, as these operations cannot be implemented “bitwise”, and their standard fault-tolerant implementations require measurement.     

Computational aerodynamics on large computers

Three examples of advances in computational aerodynamics—three-dimensional inviscid transonic analysis, design calculations for wings, and the computation of viscous-induced aileron buzz—are reviewed. The importance of large computers in promoting these kinds of advances and the need for continuing increases in computer size and speed are emphasized. NASA's plans for a numerical aerodynamic simulation facility, intended to provide the aeronautics community with a substantial increase in computer capability for the 1980s, are briefly described.     

Effects of computers on Japanese schools

In this paper I consider how the computer can or should be accepted in Japanese schools. The concept of teaching in Japan stresses learning from a long-term perspective. Whereas in the instructional technology, on which the CAI or the Tutoring System depends, step-by-step attainments in relatively short time are emphasized. The former is reluctant in using the computer, but both share the Platonic perspective which are goal-oriented. However, The Socratic teacher, who intends to activate students' innate disposition to be better, would find another way of teaching and use of the computer.     

The use of speed-up techniques for a speech recognizer system

In speech recognition, not just the accuracy of an automatic speech recognition application is important, but also its speed. However, if we want to create a real-time speech recognizer, this requirement limits the time that is spent on searching for the best hypothesis, which can even affect the recognition accuracy. Thus the applied search method plays an important role in the speech recognition task, and so does its efficiency, i.e. how quickly it finds the uttered words. To speed up this search process, various ideas are available in the literature: we can use search heuristics, multi-pass search, or apply a family of aggregation operators. In this paper we test all these methods in turn, and combine them with a set of other novel speed-up ideas. The test results confirm that all of these techniques are valuable: using combinations of them helped make the speech recognition process over 12 times faster than the basic multi-stack decoding algorithm, and almost 11 times faster than the Viterbi beam search method.     

Quenched physics on APE computers

The author summarizes some of the physics results obtained by groups using computers of the APE family.     

Data-parallel programming on MIMD computers

The implementation of two compilers for the data-parallel programming language Dataparallel C is described. One compiler generates code for Intel and nCUBE hypercube multicomputers; the other generates code for Sequent multiprocessors. A suite of Dataparallel C programs has been compiled and executed, and their execution times and speedups on the Intel iPSC/2, the nCUBE 3200 and the Sequent Symmetry are presented     

Thermal testing on reconfigurable computers

Ring-oscillators are useful to monitor the thermal status of reconfigurable computers. No analog parts exist, and the sensors can be dynamically inserted, moved, or eliminated     

Microprocessor-based computers

The development of the computer and the evolution of the integrated circuit have been intertwined since the first commercial IC appeared in 1961. The author explores microprocessor history and ponders future developments