Showing papers on "Product design specification published in 1994"

Integration analysis of product decompositions

Abstract: This paper describes a methodology for the analysis of product design decompositions The technique is useful for developing an understanding of the "system engineering" needs which arise because of complex interactions between components of a design This information can be used to define the product architecture and to organize the development teams The method involves three steps: 1) decomposition of the system into elements, 2) documentation of the interactions between the elements, and 3) clustering the elements into architectural and team chunks By using this approach, development teams can better understand the complex interactions within the system, thus simplifying the development process for large and complex projects arranged in chunks The choice of product architecture has broad implications for product performance, product change, product variety, and manufacturability Product architecture is also strongly coupled to the firm's development capability, manufacturing specialties, and product strategy Selecting the proper architecture of the product is an extremely influential decision which must be made during the concept development and system-level design phases of the project; the architecture defines the sub-systems upon which the team will work for the bulk of the development effort In product development, analysis of the product decomposition provides valuable insight into the structure of the problem and the choice of architecture The integration analysis presented in this paper considers the interactions which occur between the elements of the decomposition The building blocks (called chunks) which result from integration analysis can be used to define the product architecture and to structure the development teams Examples of architecture and team structure can be found in any highly engineered product In the automobile industry, development programs include hundreds or thousands of team members It would be impractical to design the entire vehicle at once (too complex); nor would it be possible to develop the thousands of components one at a time (too slow) The vehicle is decomposed into a few major systems: body, powertrain, chassis, interior, climate control, electrical, and trim Each of these major systems is in turn decomposed into a large number of sub-systems, resulting in hundreds of interconnected pieces with names like: passenger restraint system, fuel delivery system, remote entry system, etc Finally, these sub-systems are decomposed into component parts which are designed and tested individually and together The decomposition of the vehicle into sub-systems and components facilitates the rapid development of the individual pieces, yet this strategy does not address the needs for integration of the components' functions during the development process

Managing Product Definition in High-Technology Industries: A Pilot Study:

Abstract: Product definition creation and management are critical aspects of the new product development process. A well-developed product definition reflects understanding of customer and user needs, the competitive environment, technology availability, and regulatory and standards issues. A robust product definition is one that stands up to challenge and guides the product development process, allowing the development team to make tradeoffs and decisions quickly and effectively. This article examines the product definition creation and management processes at six major U.S. electronics companies. Customer and user needs assessment is a particularly critical aspect of product definition; clear, widespread communication of product definition elements throughout a product development team is important; and change to a product definition during product development must be carefully and explicitly managed to obtain the best chances of overall product success. Many of the firms in this study used surprisingly rudimentary procedures to bring together the requisite product definition information and failed to distinguish the creation of product definition as an important phase of the product development process. Further, few of the firms understood that product definitions will change during product development and they did not have mechanisms for managing that change.

Effects of concurrent engineering on make-to-order products

Abstract: An increasing number of manufacturing organizations are using concurrent engineering product development processes, which rely on parallel scheduling of activities throughout the product development cycle. This study examines the impact of such practices on product development time, product quality, and delivery leadtime. Using data obtained from structured interviews with product managers and engineers, six hypotheses are tested using a sample of 31 make-to-order (MTO) products from several industries. The results suggest that concurrent engineering may he appropriate for incremental innovation, but may have some "hidden costs" in the form of increased defects when applied to new "breakthrough" innovations. However, this strategy may be entirely suited to a specific customer segment that is willing to work with the manufacturer on debugging the product in the field. The study points out the importance of considering the hidden costs of concurrent engineering, and discusses the strategic implications of such decisions for technology managers. >

The specification of business rules: A comparison of selected methodologies

Abstract: Business rules are an important element of information systems. The notion business rule encompasses different phenomena; therefore, some classification criteria are presented and several examples are introduced to demonstrate different types of business rules. Given their practical importance, the necessity of a consistent treatment in the life-cycle of information systems is obvious. Therefore, commonly used functionand data-oriented methodologies for systems analysis are examined with respect to their ability to express business rules. It is shown that common methods are insufficient or at least inconvenient for a complete and systematic modeling of business rules. Some relevant enhancements of these methods are more powerful but still emphasize only certain aspects and types of business rules. Keyword Codes: D.2.1; H.2.m

Quality of structural timber-product specification system required by end-users

Abstract: Interviews conducted with the end-users of timber products revealed that their knowledge of timber is very poor. However, building contractors are not satisfied with the quality of timber, primarily as a result of its excessive warp. Their requirements are not passed on to the producers in the forest and sawmill industry. The quality of a timber product should be described in a specification of requirements for each individual product. In this paper, a systematic analysis of the end user's expectations is presented and is illustrated using a product specification for wall studs. The proposed acceptance levels are based on interviews with contractors and derived from the requirements set for the wall. The current grading rules are more generous than our proposal. Field tests by carpenters showed that our proposal limits appear to be reasonable. A study of commercially-available studs showed that it should be possible both technically and economically to produce studs which fulfil our requirements. If timber is to hold its own as a building material, the forest and sawmill industry will have to produce products which match the end user's requirements.

Observations on Modes of Incremental Change in Design

Abstract: SUMMARY This paper presents a framework for the classification of modes of historical development of normal design, and for tracing this development as products mature. Normal design involves the incremental development of an existing design principle. Designs are defined in terms of sets of explicit and implicit attributes, and the framework is based on a model in which design involves searching within a design space, subject to the requirements of a product design specification. Five modes of design change are identified: design parameter space exploration; improvement in understanding of design attribute relationships; change in product design specification; modification of the feasible design space; and adoption of a new design principle. These modes of change are illustrated by considering the development of automotive engine piston design.

A Functional Data Model for Assemblies Used to Verify Product Design Specifications

Abstract: During the design of a product periodic reviews must be conducted to verify that the product will meet its specification. However, there are few, if any, computer-based design systems that aid in engineering processes other than those involving low-level geometry. This paper describes two applications that use a functional representation of a product to aid the designer during the redesign process. The applications are aimed at assisting designers in checking that a design meets all the requirements in a product's specification. The form of the data used by the applications is defined by a data model that allows the representation of the function of each feature, component and assembly in the product. This functional data model has the strength that it can represent a product as both a structural and a functional hierarchy. The paper concludes by describing results of experiments using a mechanical engineering product as a case study.

Evaluating the relationship between product and user

Abstract: The paper describes a research project which seeks to develop a conceptual model of the process of product design evaluation. The paper presents a method for evaluating concept design proposals by means of quantifying the attributes, in user terms, that a particular product should possess. The work is based on current product design practice and a computer aided evaluation system tool is used to implement the evaluation methodology.

Object-oriented product modelling for computer-integrated manufacturing

Abstract: Design representations currently used in CAD systems are inadequate for the full integration of CAD with planning and production systems used in automated manufacturing facilities. To facilitate this integration and adequately support engineering and managerial activities in computer-integrated manufacturing systems (CIMS), product design representation should satisfy at least the following requirements: information completeness, data and knowledge encapsulation, and data model accessibility. An object-oriented product model has therefore been developed to satisfy these requirements and provides for the design representation of a product. The model has a multi-level hierarchical structure incorporating the following six classes of objects: product, sub-assembly, part, CSGtree, solid primitive and feature. Each of these classes provides a particular set of information required by design and manufacturing. The product model has been implemented in Smalltalk as part of an integrated modelling system...

Design for manufacture

Abstract: Many industrial manufacturing problems and inefficiencies can be traced back to the design process. Substantial reductions in manufacturing costs can result from revisions at the design stage and such measures can crucially affect the success of a product. Often the benefits of a redesign are realized too late.

A morphological approach to product design in a concurrent engineering environment

Abstract: The development of product design in a concurrent engineering environment requires the consideration and inclusion of life cycle factors early in the design process. This paper proposes a product design framework where these factors are considered. The phases of product design in a concurrent engineering environment include: design requirements, design functions, design alternatives, design attributes, and design environments. A five-step algorithm is proposed by which the optimal design alternative, among all the feasible alternatives, is selected. In order to illustrate the proposed framework, the design of a braking system is presented in each phase. A morphological approach to product design is proposed that consists of two related morphologies. Morphology 1 addresses the innovative aspect of product design. Morphology 2 considers the computational and optimisation aspect of product design. In conclusion, an integrated approach which reconciles both morphologies is suggested.

The importance of formal specification in the design of hardware systems

Abstract: This paper discusses the rules or guidelines to follow when writing a system specification. These guidelines were derived from an investigation to evaluate how people understand a written specification. The specification can be written at three basic levels: (a) the designer/manufacturer specification, (b) the supplier/retailer specification, (c) the buyer/user specification. The rules relating to the writing of these specifications are discussed.

System and method for evaluating product design specification

Abstract: PURPOSE:To generate relation among defective phenomena of past trial products, evaluation items at the time of an analysis of a product, and various elements of respective designs of the product and to evaluate and optimize a design specification plan for a new product on the basis of the relation. CONSTITUTION:A trial product data management part 24 has data including design specification defect information on existent trial products and a design knowledge management part 25 has respective analytic programs for the evaluation items. Feature quantities of a product shape and material are extracted from the design specification plan for the new product, data having feature quantities similar to the extracted feature quantities are take out of the trial product data management part 24, and a defect causal relation generation part 26 generates the relation (causal relation) among three elements, i.e., the defect phenomena, evaluation items, and various design elements. On the basis of the defect causal relation, an evaluation order generation part 28 generates the order of the evaluation items to be evaluated. In this order, the evaluation items are analyzed by a simulation program stored in the design knowledge management part 25 and a design plan evaluation part 42 decides whether or not the values of various design elements of the inputted product design specification plan need to be corrected on the basis of the analysis results.

Concurrent Product Design and Manufacturing

Abstract: Publisher Summary This chapter describes the difficulties in concurrent product design and manufacturing. It explains the foregoing methodologies and practical procedures for solving the difficulties. Concurrent engineering represents an ideal configurational system for actual product design and manufacturing. This has advantages over the usual sequential systems in use. In industrial companies, each work activity of product planning, research and development, product design, manufacturing and marketing is performed in the corresponding division. When company scale is large, communication among the divisions is not smooth. Such inefficient communication may create obstacles for producing products with a higher product performance and a lower product manufacturing cost. In the product design, configurations or shapes of products are determined under the evaluative criterion of the product performance. On the other hand, in the process design for manufacturing, methods for realizing the designed shapes are determined under the criterion of the manufacturing cost. The chapter describes the advantages and difficulties of concurrent decision making.

A structured approach to requirements specification for software-based systems using operational procedures

Abstract: This paper describes a specification notation and specification methodology that use the operational procedure construct to formulate a complete description of a system. The specification that is generated captures the operation of the system, manages the evolution of the operation of the system, and facilitates the rapid formulation and adaptation of implementation models for software-based systems. >

Redesigning hardware-software systems

Abstract: During the life cycle of a digital reactive real-time system implemented as a hardware-software board or chip, some of its components must be redesigned, either because a refocusing of the product market resulted in a specification change, or because bugs in the specification were found at a later stage of the design. We address the problem of automatically checking if a new version of a specification can utilize a hardware-software implementation of a previous version of the same specification by just changing the software portion of the design. The redesigning strategy we propose is divided into four phases. In the first phase, we check which parts of the specification were changed. In the second phase, we extract timing constraints from the previous hardware implementation that must be satisfied by the new software implementation. Then, we schedule and select the instructions in the software routine such that the timing constraints are observed. Finally, we check if the final implementation satisfies the specification rate constraints of the design. We present an example of a keyboard/mouse device, and we show that the hardware-software synthesis system can be made robust with respect to small changes in the specification. >

An expert system for feasibility assessment of product development

Abstract: This article presents an expert system used for assessing the chances of success of a new product. This system was successfully used in a commercial environment for the development of a pharmaceutical product. This system is not limited to specific aspects of a specific product nor to a particular domain. The domain considered comprises economic, financial, and marketing aspects. The expert system encompasses relationships among the many factors of the decision-making process across these domains. This approach is a dynamic one that, beyond today's choices, will help with future decisions.

Accelerating new product development : an empirical test of a hierarchy of implementation

Abstract: Over the past few years there has been an emphasis on methods a firm can use to speed up its new product development process. Millson, Raj, and Wilemon [1992] have proposed a hierarchy to the implementation of these methods. They argue that companies which accelerate in accord with this hierarchy will experience better results. In this paper this hierarchy is tested, both for its effect on faster new product development and financial performance. The results of the empirical study show that companies that accelerate in accord with the hierarchy do manage to develop their new products faster, and do have a better financial performance. Companies that accelerate their new product development but do not pay special attention to the order of implementation of the acceleration methods do tum out new products faster too. However, they do not experience an improvement in their financial performance.

Application Protocol, Initial Graphics Exchange Specification (IGES), Layered Electrical Product

Abstract: An application protocol is an information systems engineering view of a specific product The view represents an agreement on the generic activities needed to design and fabricate the product the agreement on the information needed to support those activities, and the specific constructs of a product data standard for use in transferring some or all of the information required. This application protocol describes the data for electrical and electronic products in terms of a product description standard called the Initial Graphics Exchange Specification (IGES). More specifically, the Layered Electrical Product IGES Application Protocol (AP) specifies the mechanisms for defining and exchanging computer-models and their associated data for those products which have been designed in two dimensional geometry so as to be produced as a series of layers in IGES format The AP defines the appropriateness of the data items for describing the geometry of the various parts of a product (shape and location), the connectivity, and the processing and material characteristics. Excluded is the behavioral requirements which the product was intended to satisfy, except as those requirements have been recorded as design rules or product testing requirements.

DICE MO-a collaborative DFMA analysis tool

Abstract: The ability to reason about product features and resource capabilities while developing manufacturing processes allows for finely tuned production processes. Conversely, providing a design team insight into the manufacturing process and the resources at hand will enable fine tuning of the design for manufacturing and assembly. The DICE-Manufacturing Optimization program investigated support for collaboration between product design teams and process development teams. The primary output of the investigation is a prototype software system that provides production cost and yield estimations determined from EXPRESS based product and enterprise information models. Support is provided for feedback of suggested product design changes from the process development team to the product design team. >

Issues in real-time process controller realization

Abstract: The first step in the software development process is the construction of a requirements specification. Ideally such a specification expresses all requirements to be posed upon the software to be developed. Current formal methods lack one desirable property: their use requires skills that are often not possessed by specialists from other disciplines. This lack of understandability complicates the realization of systems. In this paper we address problems that arise in the specification of timing requirements for a software controller. It turns out that such requirements are often implicitly present in the domain oriented specification. This process is illustrated with a case study. Finally we address solutions for the problems encountered, which emphasize the need for developing specification formalisms that are suited to specialists from various disciplines. >

Automatic verifying approach for product specification using FTA

Abstract: We propose a verification method for software specification. In order to avoid software faults, our method derives safety assertions using FTA, computes the behavioral graph of specification and analyzes statically whether this graph satisfies safety assertions. Moreover, when there exists an assertion which can not hold, our method localizes software design faults. >