Considerations for the design of array processing languages

This paper summarizes the major results of a formal survey of array processor users and indicates how these results were used in the design of a language suitable for array and vector processors. A comparison is also given with an informal survey of other large-scale computer users, which concluded that the best plan was to extend Fortran 77 to meet the requirements for array processing.     

Array automata and operations on array languages

Array automata acting on scenes (two dimensional tapes) are defined. The set of scenes accepted by array automata are proved to be equivalent to the set of arrays generated by array grammars. Certain operators like substitution, homomorphic replication and insertion are extended to sets of arrays. These operators yield interesting classes of pictures.     

Integrating distributed array processing into EMAS 2900

This paper describes the integration of initially one, and later a second, ICL Distributed Array Processor (DAP) into a dual ICL 2972 installation running the Edinburgh Multi-Access System (EMAS). The alterations made to each level of the operating system are briefly described, along with the methods for mounting some of the relevant ICL DAP compiler software. Software enhancements to enable multi-programming of the DAP and a locally designed method for DAP data area expansion are also described. A brief résumé of the user facilities available is included, along with operational policies and some utilization figures.     

Message scheduling for array re-decomposition on distributed memory systems

For many parallel applications on distributed memory systems, array re-decomposition is usually required to enhance data locality and reduce the communication overheads. How to effectively schedule messages to improve the performance of array re-decomposition has received much attention in recent years. This paper is devoted to develop efficient scheduling algorithms using the compiling information provided by array distribution patterns, array alignment patterns and the periodic property of array accesses. Our algorithms not only avoid inter-processor contention, but also reduces real communication cost and communication generation time. The experimental results show that the performance of array redecomposition can be significantly improved using our algorithms     

Tensor-based multiple denoising via successive spatial smoothing,low-rank approximation and reconstruction for R-D sensor array processing

The parameter estimation problem from noisy signal measurements plays a key role in several practical applications in the array signal processing area ranging from telecommunications and radar to biomedical and acoustics. The performance of parameter estimation techniques is sensitive to the signal-to-noise ratio (SNR) and severely degrades in noisy scenarios. Classical denoising using SVD low-rank approximation and its tensor counterpart known as higher order SVD (HOSVD) have been widely applied as a preprocessing step to improve the SNR of the received signal. In this paper, we propose the tensor-based multiple denoising (MuDe) approach that successively applies spatial smoothing, denoising and reconstruction to the noisy data. By taking into account the knowledge of the model order and by exploiting subarrays created by the spatial smoothing, we can successively denoise the data by means of HOSVD-based and SVD-based low-rank approximation for tensor and matrix data, respectively. We show that our proposed approach significantly reduces the noise level, allowing a more accurate estimation of parameters compared to state-of-the-art matrix-based and tensor-based techniques without decreasing the sensor array aperture.     

Algebraic tools for language processing

A language space provides a unified framework to deal with the properties of language constructs by associating them with their specification rules. The concrete syntax is represented by segments of the language space. The semantics is given by derived operations of the algebras where these constructs are interpreted by the processing tools operating on the language space. We examine in this paper only processing tools that collect syntactic information over the language space. Tools involved in semantics processing such as translators and interpreters are also integrated in the language space but are not discussed here.     

Portability—some experiences with FORTRAN

During the development of a portable problem-oriented language processor a number of unexpected difficulties and incompatibilities in various FORTRAN compilers were encountered. These are related, and an approach which minimizes the problems suggested.     

一种新型柔性触觉阵列传感器信号处理电路设计

依据一种利用压阻特性的3×3点阵的柔性触觉传感器,设计了针对这种新型柔性触觉传感器的信号处理电路。该电路能完成信号放大、阵列信号的选通、A／D转换以及通过LED电路对其信号的采集。并详细地阐述了电路的原理和所用芯片的功能。所设计的信号处理电路能够判断出这种触觉传感器单元所受三维加载力的大小和位置。通过在正向压力的加载试验,验证了电路的可行性。     

A cellular logic array for image processing

A cellular logic image processor employing 192 cells in a 16 by 12 hexagonal array is described. The processor has been constructed and its performance assessed. The various classes of functions which can be implemented in the cellular array are discussed and sample programs explained in detail.     

为C++语言开发长度可变的数组类模板

本文详细讨论了可以代替C 数组的C 数组类模板的设计及实现过程，并举例说明了数组类模板的使用。     

An effective framework for asynchronous incremental graph processing

Although many graph processing systems have been proposed, graphs in the real-world are often dynamic. It is important to keep the results of graph computation up-todate. Incremental computation is demonstrated to be an efficient solution to update calculated results. Recently, many incremental graph processing systems have been proposed to handle dynamic graphs in an asynchronous way and are able to achieve better performance than those processed in a synchronous way. However, these solutions still suffer from suboptimal convergence speed due to their slow propagation of important vertex state (important to convergence speed) and poor locality. In order to solve these problems, we propose a novel graph processing framework. It introduces a dynamic partition method to gather the important vertices for high locality, and then uses a priority-based scheduling algorithm to assign them with a higher priority for an effective processing order. By such means, it is able to reduce the number of updates and increase the locality, thereby reducing the convergence time. Experimental results show that our method reduces the number of updates by 30%, and reduces the total execution time by 35%, compared with state-of-the-art systems.     

Three-dimensional, wavefield imaging of broadband seismic array data

This paper describes an implementation of a three-component, three-dimensional plane wave migration method to image P-to-S converted waves that arrive following the direct P waves of teleseismic earthquakes. The programs described assume that the input data have been deconvolved to produce a set of vector impulse response functions with the initial P pulse centered at time 0. This method was implemented as three different application programs called pwstack, pwmig, and gridstacker. pwstack produces local-scale plane wave decompositions using the pseudostation concept. The output of pwstack is an estimate of the plane wave response over a grid of slowness vectors interpolated onto a regular grid in space. The Gaussian smoother that is used for the pseudostation method has the additional benefit of serving as a type of spatial antialiasing filter. The program called pwmig takes the output of pwstack and inverts the plane wave data for radial and transverse scattering potential using an inverse generalized Radon transform. Data can be back-projected using a conventional longitudinal, radial, transverse coordinate system or a novel depth-variable method that computes a transformation matrix linking each vector sample to an equivalent dipping-layer coordinate system at the corresponding scattering point. Because pwmig is a prestack method, a final program, gridstacker, is needed to stack data from multiple events that characterize real data. gridstacker is a general solution for stacking data with different grid geometries and variable data quality. Weighting functions can be defined externally by a user-supplied recipe or one can use a set of robust estimation methods coded in gridstacker. The programs are validated with simulation data produced by recently developed elastic finite-difference code and a model that simulates the edge of a subduction zone. Finally, I show an example of an application of these programs to image the western United States with the USArray.     

An algebraic model for programming languages

The language of universal algebras is used as a model for programming language specification. BNF rules are employed for specifying the signature of the language algebra instead of the context free syntax. The algorithm for program evaluation is inductively defined by the following universal algebraic construction:

Any function defined on the generators of a free algebra taking values in the carrier of another similar algebra can be uniquely extended to a homomorphism between the two algebras.

Any conventional programming language can be specified by a finite set of BNF rules and its algebra of symbols is generated by a finite set of generator classes. Thus any function defined on the finite set of generators offers an algebraic mechanism for a universal algorithm for source language program evaluation.     

Exorcise—an algorithm for detection of spurious values and prediction of missing data

A FORTRAN program is presented which generates a statistical model of broadscale spatially coherent data, and from that model identifies and removes outlying data values. The algorithm also interpolates missing data values by making use of this model, as well as the assumption of broadscale coherence. Examples of the application of this technique to geomagnetic data are presented. A significant improvement in the statistical efficiency and consistency of subsequent estimators is seen to obtain from preprocessing data with this method.     

Speech and Language processing as assistive technologies

We are delighted to bring you this special issue on speech and language processing for assistive technology. It addresses an important research area that is gaining increased recognition from researchers in speech and language processing as a rich and fulfilling area on which to focus their work, and by researchers in assistive technology as the means to dramatically improve communication technologies for individuals with disabilities. This special issue brings a wide swath of approaches and applications highlighting the variety this area offers.     

Parallel programming with logic languages: A survey

Formal properties of logic languages are largely studied; however, their impact on the practice of software design and programming is currently minimal. In this paper we survey some interesting representatives of the family of logic languages aiming at comparing the different capabilities they offer for designing and programming parallel systems. The logic languages Prolog, Aurora, Flat Concurrent Prolog, Parlog, GHC, and DeltaProlog were chosen, because a suitable set of relevant examples has been published, mostly by the language designers themselves. A number of sample programs is used to expose and compare the languages with respect to their object oriented programming capabilities for multiprocess coordination, interprocess communication, and resource management. Special attention is devoted also to metaprogramming as well, seen as a useful technique for specifying and building the operating environments of the languages themselves. The paper ends with a discussion on positive and negative features found comparing these languages, and indicates some guidelines to be followed in the design of new logic languages.     

一种面向数据流处理的VLIW阵列处理机设计

针对高密度数据计算的要求,提出了一种VLIW处理器阵列多芯片互联的简单方法,通过独特的微码结构,建立具有可配置特征的高速数据通道的控制模型,适合构建高性能的媒体处理器阵列,模型能有效地改善系统扩展所需要的灵活性,实现高带宽的存储器接口和高性能的总线控制结构,提高了数据存取的连续性和灵活性,避免了运行过程中大量不必要的系统中断和功能切换开销,可显著提高数据处理带宽。     

The definition of comments in programming languages

This paper examines the concept of comments in programming languages and answers the questions: Why are they needed? How are they defined and implemented in existing languages? What should be provided in future languages?