Development of CORBA-based engineering applications from legacy Fortran programs

A majority of scientific and engineering applications in aerodynamics and solid mechanics are written in Fortran. To reduce the high cost of software development, NASA researchers reuse most of the legacy Fortran codes instead of developing them from scratch in the numerical propulsion system simulation project. In this paper, we present an efficient methodology for integrating legacy applications written in Fortran into a distributed object framework. Issues and strategies regarding the conversion and wrapping of Fortran codes into common object request broker architecture objects are discussed. Fortran codes are modified as little as possible when they are decomposed into modules and wrapped as objects. We implement a wrapper generator which takes the Fortran application as input and generates the C++ wrapper files and interface definition language file. Tedious programming tasks for wrapping the codes can therefore be reduced.     

Assisting comprehension of animation programs through interactive code visualization

Visual languages have been widely used to help people create animation programs. However, current programming environments lack features supporting efficient code exploration and program comprehension, particularly for understanding relationships among parts of animation programs. In this paper, we present novel interactive visualizations aimed at helping people to understand animation programs. We conducted an empirical study to evaluate the impact of these visualizations on programmer comprehension of the code, showing that our approach enabled programmers to comprehend more information with less effort and in less time. This result is potentially significant because it demonstrates an approach for helping users to explore and understand animation code. We anticipate that this approach could be applied in a wide variety of animation programming tools, which could ease common animation programming tasks that require understanding code.     

Setting checkpoints in legacy code to improve fault-tolerance

In this paper we describe the results of a study of the insertion of checkpoints within a legacy software system in the aerospace domain. The purpose of the checkpoints was to improve program fault-tolerance during program execution by rolling back system control to a saved state from which program execution can continue. The study used novice programmers for the determination of where the checkpoints were to be added. The focus was on the programmer’s understanding of the code, since this affected how the checkpoints were placed. The results should provide guidance to those interested in improving the fault-tolerance of legacy software systems, especially those written in older, nearly obsolescent programming languages.     

Tools to aid in discovering parallelism and localizing arithmetic in Fortran programs

We describe a collection of software tools that analyse and transform Fortran programs. The analysis tools detect parallelism in blocks of code and are primarily intended to aid in adapting existing programs to execute on multiprocessors. The transformation tools are aimed at eliminating data dependencies, thereby introducing parallelism, and at localizing arithmetic in registers, of primary interest in adapting programs to execute on machines that can be memory bound (common for machines with vector architecture). The tools are unified conceptually by their use of a set of conditions for data independence; these conditions have been implemented so as to combine tool analysis with user/tool interaction. We include timing results from applying the tools to programs intended for execution on two machines with different architectures — a Sequent Balance and a CRAY-2. The tools are written in Fortran in the tool-writing environment provided by Toolpack and are easily incorporated into a Toolpack installation.     

Constraint-defined manifolds: A legacy code approach to low-dimensional computation

If the dynamics of an evolutionary differential equation system possess a low-dimensional, attracting, slow manifold, there are many advantages to using this manifold to perform computations for long term dynamics, locating features such as stationary points, limit cycles, or bifurcations. Approximating the slow manifold, however, may be computationally as challenging as the original problem. If the system is defined by a legacy simulation code or a microscopic simulator, it may be impossible to perform the manipulations needed to directly approximate the slow manifold. In this paper we demonstrate that with the knowledge only of a set of “slow” variables that can be used toparameterize the slow manifold, we can conveniently compute, using a legacy simulator, on a nearby manifold. Forward and reverse integration, as well as the location of fixed points are illustrated for a discretization of the Chafee-Infante PDE for parameter values for which an Inertial Manifold is known to exist, and can be used to validate the computational results.     

HP90: A general and flexible Fortran 90 hp-FE code

A general 2D-hp-adaptive Finite Element (FE) implementation in Fortran 90 is described. The implementation is based on an abstract data structure, which allows to incorporate the full hp-adaptivity of triangular and quadrilateral finite elements. The h-refinement strategies are based on h2-refinement of quadrilaterals and h4-refinement of triangles. For p-refinement we allow the approximation order to vary within any element. The mesh refinement algorithms are restricted to 1-irregular meshes. Anisotropic and geometric refinement of quadrilateral meshes is made possible by additionally allowing double constrained nodes in rectangles. The capabilities of this hp-adaptive FE package are demonstrated on various test problems. Received: 18 December 1997 / Accepted: 17 April 1998     

Linking assembly code to PASCAL programs for microprocessors

High level languages used for programming microprocessors still need some assembly code to cover all the programming requirements and aspects. Using assembly code in a high level language program introduces certain difficulties and disadvantages. Practical suggestions to minimise the use of assembly code procedures in a high level language program is presented. (The high level language discussed is pascal/64000.)     

Case study: an incremental approach to re-engineering a legacy FORTRAN Computational Fluid Dynamics code in C++

This article describes a practical approach to the manual re-engineering of numerical software systems. The strategy has been applied to re-develop a medium sized FORTRAN-77 Computational Fluid Dynamics (CFD) code into C++. The motivation for software reverse-engineering is described, as are the special problems which influence the re-use of a legacy numerical code. The aim of this case study was to extract the implicit logical structure from the legacy code to form the basis of a C++ version using an imposed object-oriented design. An important secondary consideration was for the preservation of tried and tested numerical algorithms without excessive degradation of run-time performance. To this end an incremental re-engineering strategy was adopted that consisted of nine main stages, with extensive regression testing between each stage. The stages used in this development are described in this paper, with examples to illustrate the techniques employed and the problems encountered. This paper concludes with an appraisal of the development strategy used and a discussion of the central problems that have been addressed in this case study.     

ISOLA a Fortran code and a Matlab GUI to perform multiple-point source inversion of seismic data

In this paper, a software package for multiple- or single-point source inversion is presented. The package consists of ISOLA-GUI, a user-friendly MATLAB-based interface, and the ISOLA Fortran code, which is the computational core of the application. The methodology used is similar to iterative deconvolution technique, often used in teleseismic studies, but here adjusted for regional and local distances. The advantage of the software is the graphical interface that provides the user with an easy to use environment, rich in graphics and data handling routines, while at the same time the speed of Fortran code is retained. Besides that, the software allows the results to be exported to popular software packages, like Generic Mapping Tools, while at the same time utilizing them for quality plots of the results. The modular design of ISOLA-GUI can be used by users for the addition of supplementary routines in all the stages of processing. An example of the method's ability to obtain a quick insight into the complexity of an earthquake is presented, using records from a moderate size event.     

A wrapping approach for migrating legacy system interactive functionalities to Service Oriented Architectures

Software systems modernisation using Service Oriented Architectures (SOAs) and Web Services represents a valuable option for extending the lifetime of mission-critical legacy systems.This paper presents a black-box modernisation approach for exposing interactive functionalities of legacy systems as Services. The problem of transforming the original user interface of the system into the request/response interface of a SOA is solved by a wrapper that is able to interact with the system on behalf of the user. The wrapper behaviour is defined in the form of Finite State Machines retrievable by black-box reverse engineering of the human-computer interface.The paper describes our wrapper-based migration process and discusses the results of case studies showing process effectiveness and quality of resulting services.     

使用代码动态生成技术提升Java程序灵活性

代码动态生成是指在程序运行时根据实际情况即时生成需要的类代码。它可以提高程序的灵活性,已被用于很多应用架构、脚本语言的实现中。为帮助学生掌握代码动态生成技术,探讨了相关技术的实现方法、工具的应用和教学思路。     

Linkage of Fortran programs with partitioned data sets on IBM,CDC, and DEC computers

The general concept of a partitioned data set (PDS) is outlined and a subroutine package for linkage between Fortran programs and the PDS's of IBM computers is described. Implementation of similar data structures on CDC and DEC-10 computers is also described. Several applications that have benefitted greatly from the PDS concept are discussed.     

SuSpect: A Fortran code for the Supersymmetric and Higgs particle spectrum in the MSSM

We present the Fortran code SuSpect version 2.3, which calculates the Supersymmetric and Higgs particle spectrum in the Minimal Supersymmetric Standard Model (MSSM). The calculation can be performed in constrained models with universal boundary conditions at high scales such as the gravity (mSUGRA), anomaly (AMSB) or gauge (GMSB) mediated supersymmetry breaking models, but also in the non-universal MSSM case with R-parity and CP conservation. Care has been taken to treat important features such as the renormalization group evolution of parameters between low and high energy scales, the consistent implementation of radiative electroweak symmetry breaking and the calculation of the physical masses of the Higgs bosons and supersymmetric particles taking into account the dominant radiative corrections. Some checks of important theoretical and experimental features, such as the absence of non-desired minima, large fine-tuning in the electroweak symmetry breaking condition, as well as agreement with precision measurements can be performed. The program is simple to use, self-contained and can easily be linked to other codes; it is rather fast and flexible, thus allowing scans of the parameter space with several possible options and choices for model assumptions and approximations.

Program summary

Title of program:SuSpectCatalogue identifier:ADYR_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYR_v1_0Program obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandLicensing provisions:noneProgramming language used:FORTRAN 77Computer:Unix machines, PCNo. of lines in distributed program, including test data, etc.:21 821No. of bytes in distributed program, including test data, etc.:249 657Distribution format:tar.gzOperating system:Unix (or Linux)RAM:approximately 2500 KbytesNumber of processors used:1 processorNature of problem:SuSpect calculates the supersymmetric and Higgs particle spectrum (masses and some other relevant parameters) in the unconstrained Minimal Supersymmetric Standard Model (MSSM), as well as in constrained models (cMSSMs) such as the minimal Supergravity (mSUGRA), the gauge mediated (GMSB) and anomaly mediated (AMSB) Supersymmetry breaking scenarii. The following features and ingredients are included: renormalization group evolution between low and high energy scales, consistent implementation of radiative electroweak symmetry breaking, calculation of the physical particle masses with radiative corrections at the one- and two-loop level.Solution method:The main methods used in the code are: (1) an (adaptative fourth-order) Runge-Kutta type algorithm (following a standard algorithm described in “Numerical Recipes”), used to solve numerically a set of coupled differential equations resulting from the renormalization group equations at the two-loop level of the perturbative expansions; (2) diagonalizations of mass matrices; (3) some mathematical (Spence, etc) functions resulting from the evaluation of one and two-loop integrals using the Feynman graphs techniques for radiative corrections to the particle masses; (4) finally, some fixed-point iterative algorithms to solve non-linear equations for some of the relevant output parameters.Restrictions:(1) The code is limited at the moment to real input parameters. (2) It also does not include flavor non-diagonal terms which are possible in the most general soft supersymmetry breaking Lagrangian. (3) There are some (mild) limitations on the possible range of values of input parameter, i.e. not any arbitrary values of some input parameters are allowed: these limitations are essentially based on physical rather than algorithmic issues, and warning flags and other protections are installed to avoid as much as possible execution failure if unappropriate input values are used.Running time:between 1 and 3 seconds depending on options, with a 1 GHz processor.     

数字化图书及英语交互学习RIA平台的研究

为解决基于Web学习平台交互性不足和通用性较差的问题,采用RIA技术设计了英语交互学习平台.为提高平台的实用性和内容的表现力,通过实现图书的数字化,统一了内容展示形式;通过实现手写与识别技术、拖动与碰撞技术,实现平台的富交互特性;根据英语学科的特点,提出了使用媒体标记技术实现听力与内容的同步.在此基础上,给出了系统的总体结构和基于MVVM模式的设计框架,通过采用MVVM模式,解决了软件的耦舍度和复用性问题.实例结果表明了系统的实用性.     

基于VoiceXML的语音交互平台的设计与实现

设计并实现了一种基于VoiceXML(voice extensible markup language)的呼叫中心语音交互平台.该平台以OpenVXI开源项目的VoiceXML解析器为核心,以C/S三层结构框架来设计,在集成了杭州三汇语音板卡的基础上实现了语音合成、语音识别、呼叫处理等呼叫中心的基本功能.利用该平台,电信运营商不仅能方便地建立呼叫中心,而且可以联合SP/CP(service proyider/content provider)推出各种语音增值业务.介绍了该平台的总体架构设计,并详细讲述关键技术的实现,最后给出了系统测试实例及其运行结果.     

嵌入式软件目标码仿真测试平台的研究与设计

为了满足当前提出的对安全关键软件进行目标码测试的要求,改变目标码测试工具缺乏的现状,提出了一种目标码仿真测试平台的设计方案.分析了目标码测试的特点,在此基础上提出了一种基于虚拟软件测试环境的支持嵌入式软件目标码测试的仿真测试平台的设计结构,给出了虚拟运行平台构建,目标文件静态分析、测试用例加载、测试信息采集记录和目标码覆盖率统计的解决方法.通过设计TMS320C67x目标码仿真测试平台,验证了该设计的有效性.     

AADL构件到RTLinux平台C代码的转换方法研究*

为了提高嵌入式软件开发的自动化程度,代码自动生成是一种值得采用的有效方法.在研究体系结构分析与设计语言(AADL)和RTLinux(real-time Linux)平台C代码的特性的基础上,提出了AADL构件到RTLinux平台C代码的转换规则;然后用一个实例实现了代码自动生成,从而验证了转换规则的有效性.