An environment for prototyping distributed applications

Designing a distributed application is an extremely complex task. Proper facilities for prototyping distributed applications can be useful in evaluating a design, and also in understanding the effect of different parameters on the performance of an application. We describe a language for prototyping distributed applications, that supports different communication primitives with specified delay, and provides primitives to aid debugging and evaluation. Our environment for executing distributed programs supports heterogeneous computation in which processes can execute on different hardware. Different source languages can be used for coding different modules of the processes. The system has a centralized control and monitoring facility which is based on the Suntools window system.     

An environment for distributed prototyping of real time systems

Designing and reasoning about real-time systems are difficult activities, in which timing and reactive behaviour requirements add significant complexity to system validation. In this paper, a new technique for distributed prototyping of real-time systems is presented. It enables system prototypes to be concurrently developed and tested by a geographically distributed team, in such a way that each developer can validate his or her part of the system against the other parts which are being built in other development sites. A set of tools has been implemented that supports validation of functional and time behaviour through distributed animation of graphical prototypes with a consistent vision of simulated time.     

Alphorn: a remote procedure call environment for fault-tolerant,heterogeneous, distributed systems

Alphorn, a software environment for programming distributed computer systems, is described. Programs running on different computers, possibly of different types and running different operating systems, communicate in a client-server relationship by means of remote procedure calls. This efficient construct structures programs neatly. The paper covers distributed process control, Alphorn's object-based programming style, remote procedure calls, the service interface language, configuration, runtime and debugging, and fault tolerance support     

Framework for distributed video surveillance in heterogeneous environment

In order to overcome the disadvantages of traditional centralized video monitoring system or distributed systems based on wired network, we propose a framework for distributed video surveillance in heterogeneous environment. Video flows are compressed with the scalable video encoding standard MPEG-4 and transmitted over lnternet or wireless network. Video surveillance can be performed wherever there is Internet or mobile telephone signal. The feasibility of this framework has been demonstrated with a prototype implementation. The system is cheaper and easier to achieve with simple equipments, so it can be widely used in practice.     

A message-based distributed kernel for a full heterogeneous environment

This paper presents the design and implementation of a message-based distributed operating system kernel NDOS.The main purpose of the kernel is to support a distributed data processing system and a distributed DBMS.It uses the abstraction of communication between processes as basic mechanism.In NDOS,services and facilities such as message passing and process synchronization,which are related to IPC and may cause the change of the state of a process,are integrated into a single concept,an event,The initial verdion of NDOS kernel has been implemented on a full heterogeneous environment of different machines.LANs,and OSs wih the original high-layered sys,ems and applications are still provided.     

分布异构环境下数据库访问技术的研究

详细分析了当前分布异构数据库访问技术的研究现状和发展趋势,结合Web Services的优势构造了一个基于Web Services的分布异构数据库访问系统,并阐述了系统的实现过程。该系统能够有效地支持分布式数据查询,数据源透明并且支持跨平台检索。     

A flexible environment for rapid prototyping and analysis of distributed real-time safety-critical systems

Currently, there is a plethora of low-cost commercial off-the-shelf (COTS) hardware available for implementing control systems. These range from devices with fairly low intelligence, e.g. smart sensors and actuators, to dedicated controllers such as PowerPC, programmable logic controllers (PLCs) and PC-based boards to dedicated systems-on-a-chip (SoC) ASICS and FPGAs. When considering the construction of complex distributed systems, e.g. for a ship, aircraft, car, train, process plant, the ability to rapidly integrate a variety of devices from different manufacturers is essential. A problem, however, is that manufacturers prefer to supply proprietary tools for programming their products. As a consequence of this lack of ‘openness’, rapid prototyping and development of distributed systems is extremely difficult and costly for a systems integrator. Great opportunities thus exist to produce high-performance, dependable distributed systems. However, the key element that is missing is software tool support for systems integration. The objective of the Flexible Control Systems Development and Integration Environment for Control Systems (FLEXICON) project IST-2001-37269 is to solve these problems for industry and reduce development and implementation costs for distributed control systems by providing an integrated suite of tools to support all the development life-cycle of the system. Work within the Rolls-Royce supported University Technology Centre (UTC) is investigating rapid prototyping of controllers for aero-engines, unmanned aerial vehicles and ships. This paper describes the use of the developed co-simulation environment for a high-speed merchant vessel propulsion system application.     

Primitives for distributed computing in a heterogeneous local areanetwork environment

Epsilon is a testbed for monitoring distributed applications involving heterogeneous computers, including microcomputers, interconnected by a local area network. Such a hardware configuration is usual but raises difficulties for the programmer. First, the interprocess communication mechanisms provided by the operating systems are rather cumbersome to use. Second, they are different from one system to another. Third, the programmer of distributed applications should not worry about system and/or network aspects that are not relevant for the application level. The authors present the solution chosen in Epsilon. A set of high-level communication primitives has been designed and implemented to provide the programmer with an interface independent of the operating system and of the underlying interprocess communications facilities. A program participating in a distributed application can be executed on any host without any change in the source code except for host names     

Rapid prototyping for distributed virtual environments

The authors combine rapid and exploratory prototyping techniques to capture initially unknown, interdependent requirements in the development of distributed virtual environment applications. They employ containerization to accelerate data exchange     

异构分布环境下数据获取与多态发布

随着生产全球化和协作化的发展,企业生产与外界的交互和相互依赖日益密切,出现了如何按照数据消费者的需求将企业内部多样分布的数据友好地向外发布的问题。为了解决这一问题,提出了一种基于XML和J2EE的数据获取与发布技术,并以一个报表生成系统的设计为例阐明这一技术。利用XML可以方便、准确地描述企业的数据并且可以灵活地将数据发布到Web上,而J2EE可以将异构分布的企业信息系统与Web集成起来。     

An efficient list-based task scheduling algorithm for heterogeneous distributed computing environment

The task scheduling in heterogeneous distributed computing systems plays a crucial role in reducing the makespan and maximizing resource utilization. The diverse nature of the devices in heterogeneous distributed computing systems intensifies the complexity of scheduling the tasks. To overcome this problem, a new list-based static task scheduling algorithm namely Deadline-Aware-Longest-Path-of-all-Predecessors (DA-LPP) is being proposed in this article. In the prioritization phase of the DA-LPP algorithm, the path length of the current task from all its predecessors at each level is computed and among them, the longest path length value is assigned as the rank of the task. This strategy emphasizes the tasks in the critical path. This well-optimized prioritization phase leads to an observable minimization in the makespan of the applications. In the processor selection phase, the DA-LPP algorithm implements the improved insertion-based policy which effectively utilizes the unoccupied leftover free time slots of the processors which improve resource utilization, further least computation cost allocation approach is followed to minimize the overall computation cost of the processors and parental prioritization policy is incorporated to further reduce the scheduling length. To demonstrate the robustness of the proposed algorithm, a synthetic graph generator is used in this experiment to generate a huge variety of graphs. Apart from the synthetic graphs, real-world application graphs like Montage, LIGO, Cybershake, and Epigenomic are also considered to grade the performance of the DA-LPP algorithm. Experimental results of the DA-LPP algorithm show improvement in performance in terms of scheduling length ratio, makespan reduction rate , and resource reduction rate when compared with other algorithms like DQWS, DUCO, DCO and EPRD. The results reveal that for 1000 task set with deadline equals to two times of the critical path, the scheduling length ratio of the DA-LPP algorithm is better than DQWS by 35%, DUCO by 23%, DCO by 26 %, and EPRD by 17%.     

BPL: A set-based language for distributed system prototyping

Rapid prototyping of software and hardware is recognized as a very important step in timely, cost-effective system development. The complexity inherent in designing distributed computing systems and distributed problem solutions emphasizes the need for effective rapid prototyping tools. ADL/ADS is a testbed user interface tool for experimentation with critical research and design issues pertaining to distributed data processing (DDP). The experimenter expresses a candidate distributed system in terms of experiment objects, along with attributes and relationships. The experiment objects represent hardware, software, and behavior. This paper provides a brief overview of ADL/ADS, and gives especial emphasis to the Behavior Prototyping Language (BPL) within ADL/ADS. BPL is designed for expressing Behavior Modules (B_MODULEs)—the most versatile of the behavior objects. BPL incorporates set-theoretical approaches, and provides syntax designed for effectively describing manipulations of experiment objects, and their attributes and relationships.     

Distributed object management integrating distributed information in heterogeneous environment

Organizations today need an optimized environment that builds and integrates diverse operating systems, hardware and applications. Distributed Computing provides us with a facility to transparently access all data, resources in the network. Current Research, projects that distributed object management concept along with the distributed computing environment can provide a single interface to manage the complexities of a heterogeneous environment. Using a uniform framework based on the DCE standard, we attempt to create an Object Oriented Distributed Computing Environment that will help us create open distributed applications with location independence for client applications in a multivendor network.

A better model for Open Distributed Computing aided by Object Oriented concepts is offered. Some of the research issues in realizing such a model are contemplated. We integrate an Object Manager with the OSF' DCE and discuss its benefits.     

INFOHARNESS: managing distributed, heterogeneous information

Today, important information is scattered in so many places, formats, and media, that getting the right information at the right time and place is an extremely difficult task. Developing a single software product, for example, includes the creation of documents ranging from the requirements specification and project schedules to marketing presentations, multimedia tutorials, and more. Each document may be created by a different person using a different tool, and each may be stored in a different place. InfoHarness is an information integration system, platform, and tool set that addresses these problems, managing huge amounts of herterogeneous information in a distributed environment. Through a powerful, consistent user interface, InfoHarness provides rapid search of and access to information assets including documents and parts of documents, mail messages, images, code files, video clips, Web pages with URLs, InfoHarness queries, and views of relational tables. The system makes all these artifacts available without relocating, restructuring, or reformatting the data     

PProto: An environment for prototyping parallel programs

This paper describes Parallel Proto (PProto), an integrated environment for constructing prototypes of parallel programs. Using functional and performance modeling of dataflow specifications, PProto assists in analysis of high-level software and hardware architectural tradeoffs. Facilities provided by PProto include a visual language and an editor for describing hierarchical dataflow graphs, a resource modeling tool for creating parallel architectures, mechanisms for mapping software components to hardware components, an interactive simulator for prototype interpretation, and a reuse capability. The simulator contains components for instrumenting, animating, debugging, and displaying results of functional and performance models. The Pproto environment is built on top of a substrate for managing user interfaces and database objects to provide consistent views of design objects across system tools.     

UPE: Utah prototyping environment for robot manipulators

Developing an environment that enables optimal and flexible design of robot manipulators using reconfigurable links, joints, actuators, and sensors is an essential step for efficient robot design and prototyping. Such an environment should have the right mix of software and hardware components for designing the physical parts and the controllers, and for the algorithmic control of the robot modules (kinematics, inverse kinematics, dynamics, trajectory planning, analog control and digital computer control). Specifying object-based communications and catalog mechanisms between the software modules, controllers, physical parts, CAD designs, and actuator and sensor components is a necessary step in the prototyping activities.In this paper, we propose a flexible prototyping environment for robot manipulators with the required subsystems and interfaces between the different components of this environment. This environment provides a close tie between the design parameters of the robot manipulator by the different subsystems involved in the design process. The design and implementation of this environment along with the implementation of some of the subsystems are presented, and some examples that demonstrate the functionality of the environment are discussed. This work was supported in part by DARPA grant N00014-91-J-4123, NSF grant CDA 9024721, and a University of Utah Research Committee grant. All opinions, findings, conclusions or recommendations expressed in this document are those of the author and do not necessarily reflect the views of the sponsoring agencies.     

Grape-II: a system-level prototyping environment for DSPapplications

We propose a rapid-prototyping setup to minimize development cost and a structured-prototyping methodology to reduce programming effort. The general-purpose hardware consists of commercial DSP processors, bond-out versions of core processors, and field-programmable gate arrays (FPGAs) linked to form a powerful, heterogeneous multiprocessor, such as the Paradigm RP developed within the Retides (Real-Time DSP Emulation System) Esprit project. Our Graphical Rapid Prototyping Environment (Grape-II) automates the prototyping methodology for these hardware systems by offering tools for resource estimation, partitioning, assignment, routing, scheduling, code generation, and parameter modification. Grape-II has been used successfully in three real-world DSP applications     

PROTOB: An object-oriented case tool for modelling and prototyping distributed systems

The PROTOB object-oriented methodology for the executable specification of large-scale event-driven systems is introduced and described. Two supporting features of PROTOB are also presented: the graphic and textual language that formally describes the behaviour of objects, which is based on high-level Petri nets called “PROT nets” and which is demonstrated to be more powerful than SA/RT dataflows; and a CASE environment with tools for specification, modelling, simulation and prototyping. Use of PROTOB is illustrated by discussion of the automated generation of distributed systems running on a network of VMS and UNIX computers.