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1.
Computing the Information Content of Decoupled Designs 总被引:1,自引:1,他引:0
The information content of uncoupled designs can be computed by summing the information content associated with each functional
requirement. This paper proves that information cannot be summed for decoupled designs. To overcome this problem, this paper
presents two algorithms for computing information content of decoupled designs. One algorithm is applicable to any joint probability
density function for the design parameters; the second algorithm applies only to uniformly distributed design parameters.
The algorithm for uniform distributions is based on a recursive procedure for computing the volume of a convex polytope in
n
-dimensional real space, where
n
is the number of design parameters. An engineering application of the algorithms is presented. The example demonstrates that
summing information content can significantly over-estimate total information when compared to an algorithm that accounts
for correlation. The example also demonstrates that decoupled designs can have lower information content than uncoupled systems
with the same functional requirements and similar components. 相似文献
2.
Beth Adelson 《Research in Engineering Design》1999,11(3):133-144
This work applies a theory-based framework of collaborative negotiation to some of the disputes that regularly arise during
group design. Although the framework was developed to provide general support for group work, this paper focuses on its use
as a design tool. The framework, embodied in our system NegotiationLens, has four facets. It:
1. Provides a negotiation method intended to produce gain for all parties.
2. Provides an efficient process for conflict resolution.
3. Develops working alliances.
4. Lets parties decide quickly when they should go their separate ways.
The framework produces the above results by:
• Helping parties develop well-reasoned and clearly articulated points of view (Adelson and Jordan, 1991; Conklin and Yakemovic,
1991; Conklin and Begeman, 1988; MacLean
et al
., 1991).
• Creating a context of committment and respect.
• Moving negotiating parties away from an adversarial stance and into a collaboration.
• Allowing joint construction of solutions that are more beneficial than the unilateral solutions each party initially brought
to the table.
We present our framework for collaborative negotiation, describe NegotiationLens, and present two cases in which it was used.
We present a third case, a large design project with recurrent design conflicts, and argue how NegotiationLens could have
been of benefit there. 相似文献
3.
Critical design decisions are commonly made throughout the product development process assuming known material and process
behavior. However, stochastic variation during manufacture can inadvertently result in inferior or unacceptable product performance
and reduced production yields. Stochastic simulations have been developed to estimate the end-use performance distribution
prior to the commitment of hard tooling. This article proposes a definition for integrated product and process robustness,
and extends existing stochastic methods to model the important role of the manufacturing flexibility in elimination of defects
and product optimization. The goal is to enable the designer to understand and account for not only the negative effects of
manufacturing variation, but also the positive impact of manufacturing flexibility wherein instantaneous corrections in the
manufacturing process can frequently improve the product quality and eliminate flaws in the product design. Then, a methodology
is introduced and contrasted with conventional development methods in the evaluation of best practices for development of
a molded plastic component. 相似文献
4.
We have developed a taxonomy that classifies those needs of a corporation that impact product design. We call these needs
corporate requirements. In contrast to the consumer or end-user requirements, corporate requirements come from internal sources
such as marketing, finance, manufacturing, and service. This taxonomy allows for an organized method of gathering, managing,
and retrieving the requirements. The taxonomy also helps to facilitate a broader, clearer form of Quality Function Deployment.
Generic in nature, this taxonomy provides a template with which to create taxonomies for a given product within a given company
or industry. We include an industrial case study to demonstrate this concept. 相似文献
5.
In this paper, related product functions are determined for a group of approximately 70 consumer products. Using customer
need data, a new matrix approach is introduced to identify these relationships. Techniques are then created for determining
product similarity. These techniques are clarified and validated through three case studies, including beverage brewers and
material-removal products. The results of these case studies are argued to have significant impact on design-by-analogy procedures,
benchmarking methods, mass customization strategies and modular design. The paper concludes with a discussion of applications
and related procedures for product development. 相似文献
6.
A Theory of Complexity, Periodicity and the Design Axioms 总被引:2,自引:1,他引:1
Nam P. Suh 《Research in Engineering Design》1999,11(2):116-132
One of the topics that has received the attention of mathematicians, scientists and engineers is the notion of complexity.
The subject is still being debated, as it lacks a common definition of complexity, concrete theories that can predict complex
phenomena, and the mathematical tools that can deal with problems involving complexity. In axiomatic design, complexity is
defined only when specific functional requirements or the exact nature of the query are defined. Complexity is defined as
a measure of uncertainty in achieving a set of specific functions or functional requirements. Complexity is related to information,
which is defined in terms of the probability of success of achieving the Functional Requirements (FRs). There are two classes
of complexity: time-dependent complexity and time-independent complexity. There are two orthogonal components of time-independent
complexity, i.e., real complexity and imaginary complexity. The vector sum is called absolute complexity. Real complexity of coupled design is larger than that of uncoupled or decoupled designs. Imaginary complexity can be reduced
when the design matrix is known. As an example of time-independent imaginary complexity, the design of a printing machine
based on xerography is discussed. There are two kinds of time-dependent real complexity: time-dependent combinatorial complexity and time-dependent periodic complexity. Using a robot-scheduling problem as an example, it is shown that a coupled design with a combinatorial complexity can be
reduced to a decoupled design with periodic complexity. The introduction of periodicity simplifies the design by making it
deterministic, which requires much less information. Whenever a combinatorial complexity is converted to a periodic complexity,
complexity and uncertainty is reduced and design simplified. 相似文献
7.
Information technology is the foundation for collaborative design. This paper reviews the state-of-the-art of the current
research on product modeling, and a schema for a Design-Oriented Model (DOM) containing functional, structural and management
data is proposed. The functional data explains the design purpose, function, object behavior and design rationale; the management
data is for keeping the consistency of the model data, capturing the evolution process and controlling the operation action
and authority; the structural data is the core of the model data. The integration of functional and management data directs
the model towards design integration in place of application integration. The modeling system adopts the Component Agent (CA)
mechanism that represents a complex product in an intelligent, autonomous hierarchy. A CA encapsulates the DOM data and consists
of a definer, a communicator, an adaptor and a manager. These units are responsible for defining the model data, interacting
with other agents, deriving special data and managing the constraints, version, authority and operation. Finally, several
aspect supporting the collaborative design enabled by the CADOM (CA-based DOM) are discussed, as the multi-views model, the
semantics communication between perspectives, the dynamic constraints management, the version and authority management, and
the product and process integration. The discussion indicate that the model is an information infrastructure with more capabilities
for collaborative design. 相似文献
8.
One of the major planning issues in large scale automated transportation systems is so-called empty vehicle management, the timely supply of vehicles to terminals in order to reduce cargo waiting times. Motivated by a Dutch pilot project on
an underground cargo transportation system using Automated Guided Vehicles (AGVs), we developed several rules and algorithms
for empty vehicle management, varying from trivial First-Come, First-Served (FCFS) via look-ahead rules to integral planning.
For our application, we focus on attaining customer service levels in the presence of varying order priorities, taking into
account resource capacities and the relation to other planning decisions, such as terminal management. We show how the various
rules are embedded in a framework for logistics control of automated transportation networks. Using simulation, the planning
options are evaluated on their performance in terms of customer service levels, AGV requirements and empty travel distances.
Based on our experiments, we conclude that look-ahead rules have significant advantages above FCFS. A more advanced so-called
serial scheduling method outperforms the look-ahead rules if the peak demand quickly moves amongst routes in the system.
Received: June 21, 2000 / Accepted: January 22, 2001 相似文献
9.
Graham Coates Robert Ian Whitfield Alex H. B. Duffy Bill Hills 《Research in Engineering Design》2000,12(2):73-89
This is the second of two papers surveying research in coordination approaches and systems. This paper is concerned with operational
coordination, which is aimed at coordinating activities such that the design process can be performed in a near optimal manner
with respect to time, and the allocation and utilisation of resources. Aspects of coordination categorised as operational
include resource management, scheduling and planning. The first of these two papers presents a review of coordination from
a strategic perspective, which is concerned with the decision management aspects of coordination. Greater emphasis is now
being placed on the significance of organising the design process as this affects time to market, product quality, cost, and
consequently product success. The aim of this paper is to present a fundamental review of operational coordination approaches
and systems. The 1990s has seen much progress being made towards a greater understanding and appreciation of coordination
in various disciplines through the development of a wide range of approaches and systems. However, there remains a requirement
to formally identify the key issues involved in coordination such that a widely accepted representation can be agreed upon.
Consequently, research should continue to be supported in the exploration for a unified approach to coordination which will
permit a broader and greater understanding of those aspects involved. 相似文献
10.
This paper outlines the development of an effective and consistent ‘designing-in-quality’ strategy that can be used to deal
with concepts of uncertainty, quality and robustness in engineering design. Specifically, this paper presents a decision analysis-based
robust design metric that seamlessly integrates objective evaluations on the goodness of a design alternative with the designer’s
intent and preferences. This is achieved through the development of a set of performance-reflecting dominance indices for
the attributes and their utilization in a preference-influenced multiattribute utility formulation. Such a knowledge feedback-based
decision model development will be particularly useful when dealing with complex iteration-based engineering design process
where little information on the expected outcomes may be known a priori, or where product performance is computationally expensive to evaluate. Application of this robust design metric in a multi-stage
experimentation and modeling design process is presented. The characteristics of the proposed design metric and the effectiveness
of the overall design procedure in dealing with constrained engineering design problems are examined with the aid of demonstrative
case studies and the results are discussed. 相似文献
11.
Industrial product development requires continuous improvements in work procedures as a result of constantly changing demands.
Support tools have proven to be an oft chosen way to meet new demands; however, few research efforts have been made in how to implement new tools. This article is a contribution to knowledge on carrying out the implementation of support tools. The basis consists
of four field studies performed during 1994–1999, containing 78 qualitative research interviews and focusing on the implementation
and use of different support tools. A re-analysis has been performed of selected interviews from the field studies, in total
30 interviews. This resulted in recommendations for an implementation framework, consisting of an Implementation Cycle, Organizational Change Field and Managerial Consistence, and five implementation keys: Goal setting, Kowledge Development, Anchoring at All Levels, Suitable Resources and Focus on the Individual. 相似文献
12.
In this paper, a novel technique is presented to solve tolerance design problems. To achieve the desired performance tolerance,
the technique uses a subtle, but significant, change in the design: the addition of a tuning parameter in place of an increase
in component precision. Statistical models are used to develop a framework for the tuning parameter design method. Also developed
is a new, dimensionless design metric which ranks candidate tuning parameters. A step-by-step method is developed for the
application of tuning parameters using this metric. The step-by-step tuning parameter design method is applied to a heavy-duty
manual stapler as a clarifying example. 相似文献
13.
Designing Assemblies 总被引:5,自引:0,他引:5
D. E. Whitney R. Mantripragada J. D. Adams S.J. Rhee 《Research in Engineering Design》1999,11(4):229-253
This paper presents a theory to support the design of assemblies. It brings together prior work in a new synthesis, resulting
in a top-down process for designing assemblies so that they deliver geometric Key Characteristics (KCs) that achieve top level
customer requirements. The theory applies to assemblies that take the form of mechanisms (e.g. engines) or structures (e.g.
aircraft fuselages), but has less relevance to assemblies that take the form of connective or distributive systems (e.g. hydraulic
piping). The theory shows how kinematically constrained (statically determinate) assemblies can be unambiguously designed
to satisfy geometrically-defined customer requirements. The top-down process presented here begins by creating a kinematic
constraint structure and a systematic scheme by which parts are located in space relative to each other, followed by declaration
of assembly features that join parts in such a way as to create the desired constraint relationships. This process captures
design intent by creating a connective data model that contains information to support relevant analyses such as variation
buildup, constraint analysis, and establishment of constraint-consistent assembly sequences. Adjustable assemblies, assemblies
built using fixtures, and selective assemblies can also be described by this theory. Problems arising from multiple KCs and
KC conflict can be identified. Issues unresolved by the theory are also noted. 相似文献
14.
Structure and Matrix Models for Tolerance Analysis from Configuration to Detail Design 总被引:8,自引:0,他引:8
A substantial amount of all quality problems that arise during assembly can be referred back to the geometrical design, and
especially the geometrical concept of the product, i.e. the way in which parts are designed and located with each other. Special
emphasis should thus be put on geometry design, especially during the early design phases, to try to find robust concepts
and avoid solutions that may cause down-stream production problems.
This paper presents a generic set of evaluation tools for robust geometry design encountering (i) potential tolerance chain
detection in configuration design, (ii) assembly robustness evaluation in concept design, and (iii) tolerance sensitivity
analysis in detail design. Special attention is given to the development of a new matrix-based evaluation tool for the configuration
design part. The tool presented is based on a new way of representing geometry variation constraints in an enhanced function-means
tree structure model. Different parts of the function-means tree that are of interest for analysis purposes are then extracted
and converted to matrix representation. The reason for doing this is that the structure model is most suitable for modeling,
but becomes unsuitable for analysis as the model complexity increases. For this latter purpose, the matrix representation
is far better. The use of the different tools is demonstrated in the design of a new vehicle front system for which the geometry
a priori
is unknown. 相似文献
15.
16.
Matthew I. Campbell Jonathan Cagan Kenneth Kotovsky 《Research in Engineering Design》1999,11(3):172-192
This paper provides an introduction to a new design methodology known as A-Design, which combines aspects of multi-objective
optimization, multi-agent systems, and automated design synthesis. The A-Design theory is founded on the notion that engineering
design occurs in interaction with an ever-changing environment, and therefore computer tools developed to aid in the design
process should be adaptive to these changes. In this paper, A-Design is introduced along with some simple test problems to
demonstrate the capabilities of different aspects of the theory. The theory of A-Design is then shown as the basis for a design
tool that adaptively creates electro-mechanical configuration designs for changing user preferences. 相似文献
17.
Improving Systems by Combining Axiomatic Design, Quality Control Tools and Designed Experiments 总被引:2,自引:0,他引:2
Fredrik Engelhardt 《Research in Engineering Design》2000,12(4):204-219
This paper presents an approach for solving design problems in existing designs. A design analysis with Axiomatic Design,
called Design Object Analysis, describes a product or a system in terms of Customer Needs (CNs), Functional Requirements (FRs),
Design Parameters (DPs) and Process Variables (PVs), as well as their associated Design Matrices (DMs). In this paper, the
design analysis is combined with a thorough investigation of possible problems within the design, utilizing the seven quality
tools, noise factor analysis, and designed experiments to form an approach for quality improvements and problem solving. The
Design Object Analysis helps secure valid input-factors to the designed experiments, and the designed experiments correct
or improve the assumptions made in the Design Object Analysis. Thus, a combination of product modeling by Axiomatic Design
and designed experiments overcomes shortcomings of the two methods. The benefits of performing a Design Object Analysis, as
compared to other methods, become clear when it comes to evaluating the results from the designed experiment, and preventing the problem. Once the critical parameters are confirmed, and the design matrices are updated, suggested design improvements
can then be checked against the design matrices, and the system effect of a design-change-order can be estimated. The approach
described in this paper was successfully applied and verified in a case study at a large automotive company. 相似文献
18.
This article describes an engineering process representation and modeling tool. The approach is especially suitable for describing
large-scale, mature design processes involving numerous tasks, some of which may be performed by automated computer agents.
The underlying representation is a graph of information-processing units with explicitly defined input and output feature
elements. We show that this representation is more complete than those used in previous process modeling approaches and overcomes
some of their limitations when dealing with design processes involving dependencies at multiple levels of detail. The representation
is combined with rules for automatically operating upon the graph to preserve consistency when traversing to higher or lower
levels of detail. 相似文献
19.
In the new and emerging agile manufacturing paradigm, where multiple firms cooperate under flexible virtual enterprise structures, there exists a great need for a mechanism to manage and control information flow among collaborating partners. In response to this pressing need, this paper addresses the design and implementation of an agile manufacturing information system integrating manufacturing databases dispersed at various partner sites. We propose a framework in which: (1) information is modeled in a hierarchical fashion using object-oriented methodology (OOM); (2) information transactions are specified by the workflow hierarchy consisting of partner workflows; (3) information flow between partners is controlled by a set of distributed workflow managers (WM) interacting with partner knowledge bases, which reflect partner specific information control rules on internal data exchange, as well as inter-partner mutual protocols for joint partner communications; (4) the prototype system is accomplished using the World Wide Web based on a client-server architecture. The overall approach and system provides within a dynamic environment, where virtual partnerships are synthesized in response to specific business initiatives, a dynamic and flexible mechanism to support partner information exchange and to keep the dispersed information consistent. 相似文献
20.
Vincent François Jean Christophe Cuillie`re Michel Gueury 《Research in Engineering Design》1999,11(1):55-66
This paper presents a method to integrate in a better way the finite element method in the CAD/CAM process for two-dimensional
problems, through efficient and automatic meshing and remeshing procedures. During the design step, the lack of integration
between geometric modeling and numerical analysis remains a crucial problem and it still tends to restrain the use of finite
element methods to a small number of engineers. Here we tackle the problem of the automatic remeshing of an object in the
context of minor changes in its geometry and topology without restarting the mesh generation from the beginning. We have developed
a mesh generator that is able to adapt a previous mesh, through two complementary strategies (for 2D cases) to a new geometry
without destroying the whole initial discretization. We also present the possible extension of these concepts to three-dimensional
problems. 相似文献