A Distributed Real-Time Operating System

A distributed real-time operating system, Fados, has been developed for an embedded multiprocessor system. The operating system is based on a host-target approach and provides for communication between arbitrary processes on host and target machines. The facilities offered are, apart from process communication, access to the file system on the host by programs on the target machine and monitoring and debugging of programs on the target machine from the host. The process communication has been designed in such a way that the possibilities are the same as those offered by the Ada programming language. The operating system is implemented on an MC 68000 based multiprocessor system in combination with a Unix

1 Unix is a trademark of A. T. & T. Bell laboratories.

host.     

A recovery block scheme for a VAX11/750 running unix

In this paper we describe an implementation of a scheme that is widely used in software fault tolerance, the recovery block scheme. This scheme is usually implemented using special purpose hardware and software. Our implementation runs on a VAX11/750 which has not been modified in any way. This machine uses a very slightly altered version of Berkeley's 4.2 Unix

1 Unix is a trademark of AT&T Bell Laboratories in the USA and other countries.

.     

水下航行器导引仿真系统的三维动画显示

该文利用ＯｐｅｎＧＬ图形库在ＵＮＩＸ环境下实现水下航行器导引规律的３Ｄ动画显示,论述了图形库数据结构、三维几何造型、计算机图形处理和开发软件,给出了水下航行器３Ｄ运动轨迹动画显示的主要源程序及仿真结果,对于复杂物体造型采用简便实用的拓扑点连接法,仿真实验的优良结果表明,水下航行器导引仿真中实现计算呆视化和数据可示化具有很好的直观性和更多的信息量。     

Description of a menu creation and interpretation system

The Menu Creation and Interpretation System (MCIS) is a menu system development tool that can provide the high-level control structure and the user interface for any application program or software system. MCIS simplifies the task of building menu-driven systems while presenting a user interface that is easily learned and easy to use. Human factors considerations have been stressed in the system design. A user is able to jump from one menu to another, obtain help whenever it is needed, and easily recover from errors. Menu systems created with MCIS are extensible and easily modified, enabling them to meet changing user needs. In addition, through the specification of user profiles, menu systems can be customized to meet the needs of individual users. MCIS is written in the C programming language under the UNIX

1 Unix is a trademark of Bell Laboratories.

operating system. It can be used in any environment that includes a C compiler and the UNIX standard I/O library.     

NSEDIT: A syntax-directed editor and testing tool based on Nassi—Shneiderman charts

This paper describes a programming environment for Pascal, called NSEDIT, which runs under VAX/VMS

1 VAX/VMS is a trademark of the Digital Equipment Corporation.

. NSEDIT is based upon the notion of Nassi-Shneiderman charts (abbreviated to N-S charts in this paper) and is designed for ease of use by novice programmers in a teaching situation. A key component of the system is the editor, which enables structural features of Pascal to be manipulated in terms of their N-S chart box representations. Simultaneous editing of more than one program or module is permitted. Another key feature of the system is a semiautomatic interface to the VAX/VMS Pascal compiler, with subsequent display of execution counts as part of the N-S charts. In this way users can obtain immediate feedback on the coverage of program elements by test runs, while still inside an editing session.     

弯曲成形动态模拟系统：BSIMU

本文针对自动弯曲机模具设计的关键环节之一——弯曲成形过程的实现,介绍了利用CAD技术进行动态模拟的BSIMU系统。描述了与其相关的模型的建立方法;成形动态模拟中所涉及的数据结构及处理方法;详细分析和介绍了模拟中从预处理、中间成形到边界成形全过程的整套算法及实施情况,并给出了算法框图;讨论了特殊情况的处理方法;叙述了工件在成形模拟中几何信息的获取和校正的方法;同时还讨论了本系统的适用范围。作为BSIMU的实际应用,本文最后给出了一个较为复杂的弯曲件动态成形模拟的实例。     

The Unix System and Software Reusability

The Unix system contains a variety of facilities that enhance the reuse of software. These vary from the utterly conventional, such as function libraries, to basic architectural mechanisms, such as the Unix pipe. The Unix pipe, which makes whole programs building blocks of larger computational structures, has been the primary reason for the development of a literature of useful, but specialized programs-programs that would be too costly to write in a conventional programming language such as C. It has led to high levels of program reuse both by the nature of its operation and through its effect on programming conventions (e.g., programs structured as simple filters). Another facility enhancing reuse on Unix is the on-line C source code for Unix system programs. This has led to a shared style of programming in which existing programs are used as models for new programs, allowing the reuse of ideas, algorithms and source code. Finally, the Unix system contains many other reuse enhancing facilities, such as generic facilities for screen management (curses and termcap) and program generators (lex and yacc).     

Application of an optimistic concurrency control method

This paper illustrates the implementation feasibility of an optimistic approach to concurrency control. After reviewing the approach and clarifying the underlying algorithms and assumptions, it is applied to the design of a multi-user version of an existing relational database management system. Two different system architectures for a UNIX

1 UNIX is a trademark of Bell Laboratories.

-based environment are presented and prototype implementations have been constructed. We also provide some performance statistics on the optimistic approach to concurrency control and compare it with a traditional locking protocol.     

UNIX with satellite processors

The steps necessary to extend the UNIX

1 UNIX is a trademark of Bell Laboratories.

time sharing system to a network which includes a central processor and a set of satellite processors is described. Software interfaces permit a program in the satellite processor to behave as if it were running in the central processor. Tasks are executed in parallel in several processors resulting in improved reliability and response time. The economics of such systems becomes more feasible with the reduction of the cost of CPUs and memories and the increasing demand for dedicated local computers.     

Animating simulations using TESS

Animation techniques provide for displaying the dynamics and operating strategies of a simulation graphically. Thus, both analysts and decision makers can see how a simulation represented the modeled system. Within its framework for performing simulation studies, TESS provides a framework for animating simulations. Animations are performed as a post-simulation presentation tool using color-raster graphics. Animations are shown on a schematic diagram of the system, driven by a list of the event occurrences in the simulation, and related to the simulation by a set of statements called a rule.An example animation illustrates the use of the TESS animation framework. A case study shows its application to an actual system.     

Procedural rhythmic character animation: an interactive Chinese lion dance

The creation of a stylistic animation through the use of high‐level controls has always been a design goal for computer animation software. In this paper, we propose a procedural animation system, called rhythmic character animation playacting (RhyCAP), which allows a designer to interactively direct animated characters by adjusting rhythmic parameters such as tempo, exaggeration, and timing. The motions thus generated reflect the intention of the director and also adapt to environmental obstacle constraints. We use a sequence of martial‐art steps in the performance of a Chinese lion dance to illustrate the effectiveness of the system. The animation is generated by composition of common motion elements, concisely represented in an action graph. We have implemented an animation control program that allows Chinese lion dance to be choreographed interactively. This authoring tool also serves as a useful means for preserving this part of world cultural heritage. Copyright © 2006 John Wiley & Sons, Ltd.     

Visualizing and animating the winged-edge data structure

The winged- and half-edge data structures are commonly used representations for polyhedron models. Due to the complexity, students in an introductory course to computer graphics usually have difficulty in handling these data structures and developing applications. This paper describes the authors’ effort in the development of a visualization and animation tool for teaching and learning these data structures. This tool also includes a simple pseudo-code-like language for algorithm design. Instructors may employ this tool for presentation and demonstration purposes. Students may use the simple language to develop and experiment with new algorithms before their actual implementation. The visualization and animation system may be used to explore and understand the relationship among mesh elements and algorithm execution.     

MA3D：三维造型动画系统的OOP实现

本文介绍了一个基于ＯＯＰ程序设计方法的三维造型动车集成系统，在该系统中，造型与动画具有统一的数据结构，系统提供的命令语言使得用户能够定义模型及其运动，系统输出的数据文件用以描述动画的每一帧画面，它们可以作为生成三维浓淡图的绘制程序的输入，从而生成三维动车画面。目前，系统提供了以线框图形式进行动画预演的工具。     

Easy Algorithm Animation on the Web

The animation environment Jeliot automates visualization of algorithms over the Internet. The user can visualize algorithms of his own, not merely the selection supplied by a service provider. Jeliot is based on self-animating data types: the user selects the data objects of the source code to be visualized, and Jeliot produces the animation based on operations performed on those types. We present the design of Jeliot and the principles of its implementation. In addition, we discuss the educational applications of Jeliot.     

Visual Programming System VIM

In this paper, aspects of creation of the visual programming system VIM based on filmification of application algorithms and methods are considered. Abstract self-explanatory films, which are series of frames/pictures with video, animation, audio, and other multimedia effects, are used for presentation of the method. Each frame of such a film corresponds to a certain stage, called computational step, of problem solution. A hierarchical organization of objects of such a system is suggested. The objects include both multimedia components, which demonstrate properties or an idea of the algorithm, and corresponding template programs serving for automated generation of the program created on the basis of the film specification and formulas defined by the user during the input dialog.     

Incremental View Maintenance By Base Relation Tagging in Distributed Databases

The incremental view maintenance problem deals with the efficient updating of materialized views in response to updates to base relations. This paper considers the problem in a distributed database environment, with communication cost minimization as the primary objective. The views considered are defined based on the relational join operation. The approach is to use yes/no tags as auxiliary data on tuples in the base relations to indicate whether the tuples participate in joins. These tags will help avoid sending irrelevant data over the network and thus reduce the communication cost. Two basic view maintenance algorithms are proposed using the tags. In addition to reducing communication costs, an important feature of these two basic algorithms is that they derive the exact change to views without looking at the old views. This feature allows us to maintain certain aggregates on views without actually materializing the views themselves; this feature is useful in applications such as active databases where many conditions or constraints must be tested whenever updates occur, since a condition is true exactly when some corresponding view has nonzero number of tuples. The paper then combines the use of tags with the counting algorithm to derive a tagged counting algorithm that further reduces the communication cost. The paper illustrates the algorithms by examples and studies their performance via a statistical analysis. The illustrating examples and the performance analysis show that, under uniform distribution with reasonable join participation rates, the use of tags significantly improves the efficiency of view maintenance over similar algorithms without tags. The performance analysis also identifies the situations where a particular algorithm is superior to others. The use of tags for memoing values of subexpressions in a view definition is also explored in the paper.     

Mixed feelings: expression of non-basic emotions in a muscle-based talking head

We present an algorithm for generating facial expressions for a continuum of pure and mixed emotions of varying intensity. Based on the observation that in natural interaction among humans, shades of emotion are much more frequently encountered than expressions of basic emotions, a method to generate more than Ekmans six basic emotions (joy, anger, fear, sadness, disgust and surprise) is required. To this end, we have adapted the algorithm proposed by Tsapatsoulis et al. [1] to be applicable to a physics-based facial animation system and a single, integrated emotion model. A physics-based facial animation system was combined with an equally flexible and expressive text-to-speech synthesis system, based upon the same emotion model, to form a talking head capable of expressing non-basic emotions of varying intensities. With a variety of life-like intermediate facial expressions captured as snapshots from the system we demonstrate the appropriateness of our approach.

JCAT: Collaborative active textbooks using Java

This paper describes JCAT, a Java-based system for building Web-based collaborative active textbooks on algorithms. JCAT augments the expressive power of Web pages for publishing passive multimedia information with a full-fledged interactive algorithm animation system. The system is built in such a way that views of a running program may reside on different machines, thereby making JCAT particularly well-suited for electronic classrooms. In such a setting, an instructor controls the animation, while students view the animation by pointing their Web browsers at the appropriate page.     

Computing all minimal hitting sets by subset recombination

In model-based diagnosis from first principles, the efficient computation of all minimal hitting sets (MHS) as candidates for the conflict component sets of a device is a vital task. However, deriving all MHS is NP-hard. In this paper, the principle of “Divide and Conquer” is used to decompose a large family of conflict sets into many smaller sub-families. To efficiently merge the sub-MHS to give sub-families of conflict sets, the relations between the sub-MHS and sub-families of conflict sets are exploited. Based on this, a new method called Subset-Rec-MHS is proposed. In theory, our method based on sub-MHS recombination generally has lower complexity than that based on whole MHS families, as it avoids a large number of set unions and comparisons (to minimize the family of hitting sets). Compared with the direct merge of whole MHS families, the proposed approach reduces the computation time by a factor of approximately \(\frac {7}{16}\). Experimental results on both synthetic examples and ISCAS-85 benchmark circuit conflict sets show that, in many cases, our approach offers better performance than previous algorithms.