Design Of Concurrent Systems Research Articles

Mapping Petri nets with inhibitor arcs onto basic LOTOS behavior expressions

The integration of different formal description techniques is an important feature in the design of communication protocols and concurrent systems. In this paper we address the problem of translating Petri nets with inhibitor arcs into basic LOTOS specifications, which is an important step in the direction of integrating these two commonly used formalisms. A mapping which preserves strong bisimulation equivalence is formally defined and illustrated by means of an example. The definition of the mapping enables us also to state a new result about the expressive power of the basic LOTOS subset which constitutes the mapping range.

Concurrent iterative design and the integration of finite element analysis results

To help foster concurrency in engineering design, methodologies are needed to support the interpretation and abstraction of numerical simulation results for design modification purposes. A methodology is presented in this paper for the integration of continuum-based numerical simulations into a computational system for concurrent design of mechanical components. The technique involves conversion of low-level numerical data, such as that obtained by finite element analysis, into high-level symbolic representations calledform templates. The form templates are based onrudimentary features which carry meaningful qualitative descriptions abstracted from either manufacturing and/or functional numerical simulations. The form templates are superimposed on the design's primary representation in the solid modeler to facilitate the cognitive mapping of concurrent destructive or constructive solid modeling features for design modifications. Examples are presented to demonstrate the methodology.

User interface system based on active objects

An active-object user interface system (AOUIS) is a user interface system implemented as an active object system (AOS). An AOS is a transition-based object-oriented system suitable for the design of various concurrent systems. In an AOUIS, user interface objects , which are sometimes called "widgets", are represented as active user interface objects (AUIOs). The behavior of an AUIO is defined by the transition rules, the equational assignment statements, and the event routines provided in its class definition. Furthermore, an AUIO can be constructed from its component AUIOs through structural composition as if it were a hardware object. Thus, AUIOs are better encapsulated and provide more flexible communication protocols than ordinary user interface objects. In addition, declarative descriptions of multiple views can be provided for each AUIO.

An Expert System for Concurrent Product and Process Design of Mechanical Parts

A new approach for concurrent product and process design of mechanical parts is presented in this paper. This approach enables designers to ensure that the product will be manufactured with the existing manufacturing facility at high quality and lowest cost. It is composed of an integrated expert and CAD (computer aided design) system that meets the requirements for accomplishing the concept of design for manufacturability or concurrent engineering. The system is based mainly on three tasks: firstly, developing a technique for automated feature recognition from the database of a solid modeller; secondly, interfacing the expert system tool-kit with the solid modelling system; finally, building an expert system that contains extensive information about both manufacturing facilities and product features. The expert system provides feedback about manufacturing concerns such as process limits or design inconsistencies. This work is part of the present extended research plan for developing a generic system suitable for various manufacturing practices based on design for manufacturability strategy.

Assessing the impact of structured real-time design methods

Computer systems in today's society require an increasing amount of embedded real-time software and hardware systems. Their application has introduced new problems for the software engineer related to the complexity of such systems. The early stages of the software development process are vital for the successful implementation of computer systems. Three structured design methods for real-time software systems that are common in industrial projects are compared (SCR, RTSA, DARTS). This comparison is based on the application of all methods to the specification of a commercial heating system which is in the area of 200 function points (6 person-months development time). The complete development process is supported by a heterogeneous CASE environment for reproducibility and hence better comparability. High-order Petri nets are introduced as a graphic formalism for both analysis and architectural design of concurrent systems. The methods are compared quantitatively providing different complexity metrics over time and qualitatively by subjective observations from this and other projects. In the given projects DARTS has some advantages compared to the other methods.

Architecture-directed refinement

As critical computer systems continue to grow in complexity, the task of showing that they execute correctly becomes more difficult. For this reason, research in software engineering has turned to formal methods, i.e., rigorous approaches to demonstrating the correctness of software systems. Unfortunately, the formal methods currently used in the design of concurrent systems do not provide any mechanisms for specifying and reasoning about the mapping of software to hardware. As a result, architectural constraints, even though they play an important role in the design process, are left out of the formal framework. We show how to state architectural constraints in a formal notation, how to prove that programs are allocated correctly to the underlying architecture, and how to factor architectural considerations into a program derivation process which uses a mixture of specification and program refinements. The approach is illustrated by the derivation of two related programs that solve the same problem but are designed to work on distinct architectures.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A fuzzy management decision support system for scenario analysis

Journal of Electronics ManufacturingVol. 04, No. 01, pp. 1-9 (1994) PAPERSNo AccessA fuzzy management decision support system for scenario analysisL.P. KHOO, N.C. HO and T.W. CHOAL.P. KHOOSchool of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 2263, Singapore Search for more papers by this author , N.C. HOGINTIC Institute of Manufacturing Technology, Nanyang Technological University, Nanyang Avenue, Singapore 2263, Singapore Search for more papers by this author and T.W. CHOASchool of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 2263, Singapore Search for more papers by this author https://doi.org/10.1142/S096031319400002XCited by:7 Next AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractForecasting the future is an important aspect of strategic planning. In recent years, an increasing number of corporate planners and forecasters have been turning to forecasting techniques to assist them in management decision-making. This paper presents a fuzzy management decision support system for scenario analysis. The system, developed in dBFAST, comprises two modules: data input and scenario generation. It is aimed at emulating the expert’s reasoning process in forecasting. It adopts a hybrid technique—a combination of fuzzy Delphi analysis and fuzzy reasoning—for problem solving. Three widely accepted forecasting techniques—the Delphi method, trend impact analysis and cross-impact analysis—are briefly reviewed. The hybrid technique developed and the details of the fuzzy management decision support system for scenario analysis are described. Using a case study on the penetration of computer-integrated manufacturing (CIM) in the electronics industry in Singapore as an example, the performance of the system is discussed.Keywords:Fuzzy reasoningfuzzy Delphi analysisscenario analysiscross-impact analysistrend impact analysisDelphi methodcomputer-integrated manufacturingquantitative reasoningqualitative reasoning FiguresReferencesRelatedDetailsCited By 7Multi-person Collaborative Augmented Reality Assembly Process Evaluation System Based on HoloLensJingFei Wang, YaoGuang Hu and XiaoNan Yang29 May 2022Hybrid intelligent scenario generator for business strategic planning by using ANFISSorousha Moayer and Parisa A. Bahri1 May 2009 | Expert Systems with Applications, Vol. 36, No. 4Adaptive Neuro-Fuzzy Inference System for generating scenarios in business strategic planningSorousha Moayer, Parisa A. Bahri and Ali Nooraii1 Oct 2007A PDES/STEP-based model and system for concurrent integrated design and assembly planningX.F Zha and H Du1 Dec 2002 | Computer-Aided Design, Vol. 34, No. 14A fuzzy-based genetic approach to the diagnosis of manufacturing systemsL.P. Khoo, C.L. Ang and J. Zhang1 Jun 2000 | Engineering Applications of Artificial Intelligence, Vol. 13, No. 3Designing with scenarios: A critical review of current research and practiceDespina Filippidou1 Mar 1998 | Requirements Engineering, Vol. 3, No. 1Framework of a fuzzy quality function deployment systemL. P. KHOO and N. C. HO1 Feb 1996 | International Journal of Production Research, Vol. 34, No. 2 Recommended Vol. 04, No. 01 Metrics History Received 1 August 1993 Accepted 1 October 1993 KeywordsFuzzy reasoningfuzzy Delphi analysisscenario analysiscross-impact analysistrend impact analysisDelphi methodcomputer-integrated manufacturingquantitative reasoningqualitative reasoningPDF download

Comparison of Limit Surface Approach with other Approaches in Fixture Planning with Friction

A fixture planning module is being developed as part of a computational system for concurrent product and process design. In general, three kinds of constraints such as geometric, kinematic, force constraints are considered to provide an appropriate fixturing for a given machining process. Since many fixture arrangements rely on friction to hold a part, the ability to reason about friction is an important component of fixture planning. Limit surface in force/moment space are introduced as a convenient formalism to check whether parts will slip and to help in specifying clamping forces. In this paper, the use of limit surfaces obtained either by scanning over the space of possible motions or by Minkowski sums is compared with other four approaches to establishing the relationships among applied forces and moments and the corresponding direction of sliding motion. Since the other approaches in the literature have only been applied to planar examples, the discussion in this paper will be confined to the case of a planar pressure distribution.

Structural Active Object Systems for Manufacturing Control

A structural active object system (SAOS) is a transition-based object-oriented system suitable for the design of various concurrent systems. A SAOS consists of a collection of interacting structural active objects (SAOs) whose behaviors are determine

Compilation of process algebra expressions into delay-insensitive circuits

The main advantage of delay-insensitive design of circuits is that it ensures that circuits function correctly independently of delays in their components and wires. Timing constraints do not have to be considered, which facilitates top-down design. Process algebras provide a suitable formalism for specification, design and verification of concurrent systems, but there are few methods for practical compilation of electronic circuits using these algebras. The paper illustrates such a method for the compilation of algebraic expressions to delay-insensitive circuits. Compilation if facilitated by the use of two new forms of the decision wait element. The implementation of these elements is also examined.

Distributed artificial intelligence for group decision support: Integration of problem solving, coordination, and learning

Decision support systems (DSS's) for aiding group problem-solving situations have become increasingly important for supporting and coordinating complex organizations. This paper describes a framework for designing, developing, and formalizing group problem-solving systems based on distributed artificial intelligence (DAI). Among the issues, we find the coordination mechanisms and the learning schemes to be of particular importance in supporting group problem solving. Two implementation examples, one on a network of expert systems, one on a multi-agent concurrent design system, are used to illustrate the distributed artificial intelligence approach to group decision support.

Working With Multiple Representations in a Concurrent Design System

The essence of concurrent engineering is to address multiple concerns (e.g., function, geometry, manufacturing) as a design evolves rather than waiting until the geometry of the design is complete. To support concurrent engineering a computational system must therefore be able to work with multiple representations and to keep them consistent. We have built environments for the design of assemblies and machined components in a prototype concurrent design system called Next-Cut and we use these environments to illustrate how such capabilities can be achieved. We discuss the strengths and limitations of the approach taken in Next-Cut and conclude with a discussion of directions for future work.

Concurrent tool and production system design for a surface broach cutting tool: a knowledge-based systems approach

This paper presents the economics of broaching operations, as analysed within the framework of concurrent design of the broach tool and its operating conditions. The tool is specified by its cutting teeth—tooth structure, tooth pitch and the number of such teeth—which in turn determine the length of the tool. Its operation is specified by the depth of cut per tooth and by the speed of broaching. Design constraints include broaching machine capabilities and surface finish requirements. A nonlinear mathematical optimization model, which incorporates all design variables and constraints, is developed and used to analyse broach design and operation for an illustrative case.

Fixture Planning With Friction

A fixture planning module is being developed as part of a computational system for concurrent product and process design. The module employs symbolic and numerical analyses at different levels of detail, from fast geometric checks to more time consuming force and friction analyses, depending on the completeness of the machining plan. In this paper we focus on the approaches used for analyzing fixture kinematics and clamping forces, including the analysis of friction. Since many fixture arrangements rely on friction to hold a part, the ability to reason about friction is an important component of fixture planning. Limit surfaces in force/moment space are introduced as a convenient formalism to check whether parts will slip and to help in specifying clamping forces.

A knowledge-based CAD system for concurrent product design in injection moulding

Abstract The synthesis of supplementary features of injection-moulded parts has been done empirically, since it requires profound knowledge about the features mouldability and causal effects on the properties of the part, which are not available to designers through the current CAD systems. RIBBER is a knowledge module which contains knowledge to permit nonexperts as well as mould design experts to generate acceptable supplementary features of injection-moulded pans. A knowledge-based CAD system is constructed by adding the knowledge module, RIBBER, for mould feature synthesis and appropriate CAE programs for mould design analysis to an existing geometric modeller in order to provide designers, at the initial design stage, with comprehensive process knowledge for feature synthesis, performance analysis and feature-based geometric modelling. A knowledge-based CAD system is a new tool which enables the concurrent design and CIM, with integrated and balanced design decisions, at the initial design stage of i...

A notion of entity based on petri nets

We discuss a formal model that is intended to support a modular approach to the design and verification of concurrent systems. A new notion of entity is introduced which is defined as Petri net together with a set of labellings, with each labelling treated as an access point designed for communiication with others entities or for the observation of the behaviour of an entity itself. Operations on entities, such as parallel composition, abstraction and encapsulation are defined A notion of equivalence of entities is introduced based on bisimulation. The equivalence is shown to be a congruence relation with respect to the operations introduced Finally, the application of the above model to some problems of communication protocols theory is illustrated

Concurrent design and economic justification in developing a product

SUMMARY In today's globally competitive world it is essential to design products with maximized functionality and minimized costs. An environment that facilitates the interactions between design and justification would enhance such a decision process. A conceptual framework for such a concurrent design and justification system is presented in this paper. A prototype implementation was developed to explore the usefulness of the design justification concept Actual data from the design of an electromagnetic/radio frequency shield, a component in electrical metering equipment, was used. In this implementation the design justification environment allowed the decision maker to see the potential economic implications of different design alternatives. It also enabled the decision maker to take advantage of their present knowledge and combine it with that of the environment to better analyse the design of the shield throughout the entire product development period.

On the design of reactive systems

The notion of joint actions provides a framework in which the granularity of atomic actions can be refined in the design of concurrent systems. An example of a telephone exchange is elaborated to demonstrate the feasibility of this approach for reactive systems and to illustrate transformations that are justifiable in such a process. Particular problems arise when a refinement would allow new interleavings of semantically relevant events. The meaning of a reactive computation is specified in a way that makes this possible.

Integrated environments for formally well-founded design and simulation of concurrent systems

An ongoing project concerned with the development of environments that support the specification and design of concurrent systems is reported. The project has two key aspects: an existing and working system, Clara, that supports Milner's CCS as a specification and design language; and the development of general techniques for computer-aided generation of Clara-like environments for other concurrent languages. The Clara environment is emphasized. It has two main components: support for the usage of formal techniques in the design process, and a rich and highly interactive simulation facility. A further distinguishing feature is the environment's graphical user interface which is based on a pictorial version of CCS. The semantics of CCS is defined nonprocedurally in two phases: an operational semantics given as a set of inference rules, and an algebraic semantics represented by a set of equational rules. >

Dimensional design: A software engineering tool for the design of concurrent systems

It is argued that a design representation for concurrent systems needs to be capable of representing the characteristics of sequence, parallelism and — as an essential element of the design process — refinement. The notation of Dimensional Design is outlined and examples given to illustrate its potential as such a representational tool.