Constrained FBS knowledge cell model, representation, and applications for conceptual design

A RFBSE model for capturing engineers’ useful knowledge and experience during the design process

Representation of functional micro-knowledge cell (FMKC) for conceptual design

Modern product development becomes increasingly collaborative and integrated, which raises the need for effectively and efficiently sharing and re-using design knowledge in a distributed and collaborative environment. To address this need, a framework is developed in this research to support design knowledge representation, retrieval, reasoning and fusion, which takes account of structural, functional and behavioral data, various design attributes and knowledge reasoning cases. Specifically, a multi-level knowledge representation based on the Base Object Model (BOM) is proposed to enable knowledge sharing using Web services technologies. On this basis, a multi-level knowledge reuse method is developed to support the retrieval, matching and assembly of knowledge records. Due to the tree structure of BOM, both depth-first and breadth-first searching strategies are employed in the retrieval algorithm while a novel measure is proposed to evaluate similarity. Moreover, a method based on the D-S evidence theory is developed to enable knowledge fusion and thus support effective decision-making. The framework has been implemented and integrated into an HLA-based simulation platform on which the development of a missile simulation example is conducted. It is demonstrated in the case study that the proposed framework and methods are useful and effective for design knowledge representation and reuse.

Conceptual design is an early phase in the design process, which involves the generation of solution concepts to satisfy the functional requirements of a design problem. There can be more than one solution to a problem; this means that there is scope for producing improved designs if one could explore a solution space larger than is possible at present. Computer support to conceptual design could be effective to this end, if an adequate understanding of the required design knowledge and subsequent tools for its representation and manipulation were available. This three-part series of articles describes one approach to synthesis of solutions to a class of mechanical design problems; these involve transmission and transformation of mechanical forces and motion, and can be described by a set of inputs and outputs. The approach involves(1) identifying a set of primary functional elements and rules of combining them, and(2) developing appropriate representations and reasoning procedures for synthesising solution concepts using these elements and their combination rules; these synthesis procedures can produce an exhaustive set of solution concepts, in terms of their topological as well as spatial configurations, to a given design problem. Part I provides an overview of the scope and the approach, adopted in the entire series, to identify the design knowledge required for synthesis, and a method for its validation. It specifically focuses on the extraction and representation of this knowledge. Part II describes synthesis of topological (graph structure) descriptions of possible solutions to a given problem. Part III describes a procedure for producing spatial configurations of these solutions.

In order to solve the problems of complicated design process, insufficient optimization of design parameters and low reuse of design knowledge during traditional mechanical product detailed design process, this paper proposes a rule-driven product configuration design method. Traditional mechanical product design process is divided into a number of design nodes and partially complex functions of traditional design process are defined in nodes. Design nodes are configured and connected after forming rule-driven nodes ,which sharply simplifies the configuration process of traditional design process and can realize the optimization of design parameters. The basic database that adapt to the design node is developed and the design knowledge is integrated into the basic database and node rules, which improves the configurability of the design process and better supports the parameter optimization of the design process and reuse of design knowledge. Finally, the system software is developed and the design process of Marine diesel turbocharger is taken as an example to verify the effectiveness of the method.

Engineering design tasks are mainly knowledge-intensive cognitive actions. Therefore, an adequate computer-based structure and representation of engineering design knowledge is a crucial point to support the design engineer's cognitive tasks. On the one hand, this knowledge representation should correspond to an intuitive way of thinking. On the other hand, this representation should comply with conscious systematic design methods without limiting human problem solving. In a first step of an analytical research approach, this contribution is concerned with deriving detailed requirements on a useful knowledge representation for computer-aided engineering design. For that purpose, generalised characteristics of human problem solving and information processing can be specified for design problem solving. According to their fulfilment of these requirements, eight main models of knowledge representation were compared concerning their utility to support human problem solving in engineering design. As a result of this evaluation, a useful model of knowledge representation is suggested and illustrated by an example of use.

A new function-based patent knowledge retrieval tool for conceptual design of innovative products

Knowledge and reasoning in design systems

Product design tends to be more complex and needs the effective cooperation among multidisciplinary designers and engineers. An ideal product design environment, which is both collaborative and intelligent, will be much appreciated. Agent technology is an innovative and promising approach to implementing distributed systems and is becoming popular in various areas of computing in recent years. In this paper, the dynamic nature of collaborative design process and the representation of collaborative design knowledge are presented. In order to model constantly evolving design process and the rationales resulted from collaboration, a Collaborative Product Data Model (CPDM), which extends traditional Product Data Model (PDM), and a constraint-based Collaborative Design Process Model (CDPM) are proposed. These are intended to facilitate the management and coordination of collaborative product design process and knowledge management. A design example is used to illustrate CDPM. While the system is being implemented, the architecture of our agent-based collaborative product design environment based on CPDM and CDPM is described.

Computer-aided conceptual design (CACD) aims to increase efficiency and quality of design work but with little essential progress due to the gap between abstract concept and detailed structure. In order to tackle the problem concerned with conceptual design process and automation, this paper introduces the concept of functional surface as the information carrier to link together product function and structure and describes a product genetic model to represent and organize product information. Functional surface is used to formalize the product gene, a varied-length coding scheme for functional surface and product gene is proposed, and the design process model for conceptual design is established based on product gene. Finally, a prototype system for CACD is introduced to demonstrate how a product can be designed based on the proposed model.

By analyzing the distinguishing features of the current popular weapons fault diagnosis expert system, as well as using component-based software design and complex knowledge representation methods, this paper proposes a solution of overall design and a description of user interfaces about the Weapons Fault Diagnosis Expert System Platform. It studies and discusses the complex knowledge representation about the reusable expert system. The implementation essentials in a variety of reasoning mechanisms are also discussed. It is proved that, a special weapons fault diagnosis expert system can be generated using this expert system platform and the special knowledge of the weapons fault.

Representing design knowledge as a network of function, behaviour and structure

Creativity is an important topic in design research. Attempts have been made to develop methods and tools that can help designers become more creative. Yet how and why creativity occurs is still unknown to researchers. In this paper, we propose a theoretical model for creative design. This theoretical model builds on two postulates: 1 design reasoning follows a nonlinear dynamics, which may become chaotic; and 2 there is an inverse U shaped relationship between designer's mental stress and design creativity. In the first postulate, the nonlinear dynamics assumes the form of design governing equation and can be solved by Environment Based Design EBD. The first postulate implies that design reasoning is sensitive to initial conditions, which are defined by the combination of design problem, design solutions, design knowledge, and other design related information. Since the major components in initial conditions may evolve simultaneously and are subject to continuous change during the design process, the design process is highly unpredictable. Some of the unpredictable solutions, which could be of high quality and useful, can be deemed creative. From this first postulate, three paths to creative design are derived, which specify how the initial conditions can be changed. The second postulate states that design creativity occurs when a designer is under a medium mental stress. Mental stresses are positively related to the workload associated with a design problem and negatively related to the designer's mental capacity. The workload is related to the complexity of the design problem and the amount of work in the design process whereas the mental capacity is related to the knowledge and skills required by the design process and to the designer's affect when dealing with the stresses arising from uncertainties and unpredictability of the design dynamics. To show how this theoretical model can be used to study design phenomena, an interpretation of the roles of sketching in design is presented.

The provision of automated assistance to designers is discussed. The primary concern in design is the conceptual design phase. If the problem specification is high level and deliberately vague and the designer is prepared to consider any proposal meeting some elements of the specification, then the related design is regarded as the conceptual design. The process is facilitated by providing some mechanism to record design decisions, and on that basis to make potential design decisions more evident in the representation of designs. The author identifies these activities as structural rationalization, operational rationalization, reusability, etc. These are high-level design heuristics taking different, and often not so obvious, interpretations depending on the application. Petri nets are used as a framework for carrying out the chosen design tasks. The case study has identified a number of separate steps in the design process. Each step is motivated by a clear objective, finding a distinct expression in the representation of the design. >

Effective and efficient provision and reuse of knowledge across a knowledge network in the global value chain still faces two challenges, namely the interpretability of model and the efficacy of construction. This research aims to address these challenges by proposing a novel representation model for design knowledge. First, a knowledge representation model based on the integration of the cognitive process theory and the Requirement-Function-Behavior-Structure model (C-RFBS model) is proposed to incorporate key elements from the cognitive process of designers to capture the rationale of deliberation and the context of decision-making, which the knowledge records created become more interpretable. Second, knowledge graph is employed to improve the productivity of knowledge records creation, storage and exploration. On this basis, we describe the creation of knowledge records using the C-RFBS model as well as the computational framework and methods for storing knowledge using knowledge graph. The proposed model and methods are implemented in a knowledge retrieval system on which we have conducted a fork design case study to evaluate and demonstrate the models and methods. As shown in the evaluation, the proposed model can effectively support knowledge elicitation and achieved improved performance in terms of knowledge retrieval through incorporating knowledge graph.