Development of a decision making system for selection of dental implant abutments based on the fuzzy cognitive map

Dental implant is a medical operation used to restore the functions of damaged or missing teeth. Correct implantation requires the proper selection of size and shape among the implant structures. In this paper, we propose a method of constructing a Web-based decision making system that enables the selection of a suitable type of abutment by taking into account the patient’s anatomical data and preferences that are based on an expert’s knowledge and experience for those patients. After the classification of the types of abutment that can be connected to fixtures of implants, we built a knowledge base and case base library according to the characteristics of osseous tissue and teeth shape to select optimal abutment. Moreover, we introduce a fuzzy cognitive map that takes into consideration expert’s knowledge for factors that affect implantation. After the determination of the cause-and-effect relationship among the concepts of the fuzzy cognitive map, an osseointegration factor with the highest conceptual concentration weight is inferred from the decision making system. In addition, the selection process for abutment is expressed as a decision making tree and then, it is applied for the rule-based reasoning and case-based reasoning. The optimized selection result is finally extracted based on the fuzzy membership function using fuzzy inference.     

Sandglass-type product specification management method for supporting modular design of semiconductor manufacturing equipment

The product life cycle for semiconductor manufacturing facilities has been significantly reduced as a result of the technological advancement of the semiconductor manufacturing process and the expansion of its demand. To ensure long-term market competitiveness under this environment, many companies attempt to convert their systems into mass customization production systems. In general, the specification management for semiconductor manufacturing equipment has adopted the method of making the bill of materials structure of the existing equipment into a new one based on the same physical structure and then customizing it according to a customer’s demands in the detail design phase. However, this method results in longer lead times and difficulties maintaining data consistency due to frequent design changes in connection with various derived products. We suggest a sandglass-type product specification management method to efficiently reflect varying and versatile requirements in product development and shorten the design lead time. In addition, we propose a method to support the modular design of semiconductor manufacturing equipment by classifying the standard specifications for a final product into product component and part component specifications. Finally, we develop a closed-loop product specification management system called NEXUS using our method, and apply this system to semiconductor manufacturing processes.

     

OpenPDM-based product data exchange among heterogeneous PDM systems in a distributed environment

In a global product development environment, more and more companies are implementing distributed engineering processes in order to shorten the time to market and merge different core competences. One of the important issues in collaborative product development during the whole product creation is to easily and quickly access the digital product definition models and documents of relevant partners. The essential problems of product data distribution are that each partner has to know what information to find in which system, how to collect the necessary information from individual systems, and how to assemble partial information so that it becomes complete. Even more difficult is the need to ensure the partner adapts to every change in the distribution model of information. To solve these problems, we propose the OpenPDM-based product data exchange method among heterogeneous PDM systems, which is a concept of a virtual data warehouse that provides data access to all partners in a distributed environment. The method is effective for partners who require real-time access to data residing in multiple heterogeneous PDM systems. We also implemented an integrated PDM system for logically linking product data which are physically distributed, and we used this system in a data exchange experiment.     

An integrated translation of design data of a nuclear power plant from a specification-driven plant design system to neutral model data

How to efficiently integrate and manage lifecycle data of a nuclear power plant has gradually become an important object of study. Because plants usually have a very long period of operation and maintenance, the plant design data need to be presented in a computer-interpretable form and to be independent of any commercial systems. The conversion of plant design data from various design systems into neutral model data is therefore an important technology for the effective operation and maintenance of plants. In this study, a neutral model for the efficient integration of plant design data is chosen from among the currently available options and extended in order to cover the information model requirements of nuclear power plants in Korea. After the mapping of the neutral model and the data model of a specification-driven plant design system, a plant data translator is also implemented in accordance with the schema mapping results.     

Development of an authoring framework for the simplified customization of PDM systems

Given that the amount of product data in firms is explosively increasing, a PDM system for effective data management is considered indispensable for product development. However, considerable time and specialized human resources are needed to customize a generic PDM system for satisfying the specific requirements of individual firms. To overcome this problem, we propose the use of UML object models in a PDM authoring framework. A PDM authoring framework, which provides authoring functions for the effective customization of PDM systems, will reduce the need for the intervention of PDM specialists in the design of the object models of the PDM system. We describe how a PDM authoring framework may be designed by using UML object models, and show how model-oriented application development (MOAD), in conjunction with the PDM authoring framework, can be used to build object models into a PDM system. Furthermore, we confirm the value of the framework by evaluating its performance under several conditions. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Inho Song is a postdoctoral associate in the Department of Mechanical Engineering, Carnegie Mellon University, USA. He received the Ph.D. degree in Mechanical Engineering from Hanyang University, Seoul, Korea in 2007. From 2002 to 2007, he served as a CAx team leader of the INOPS Company (CIES R&D Center), Seoul, Korea. He has developed the sketch-based CAD system for an automotive company. His research interests include collaborative design, sketch-based CAD, geometry translation, geometry compression, product data exchange, PDM/PLM, digital manufacturing, and virtual reality. Jeongsam Yang is an assistant professor in the Department of Industrial & Information Systems Engineering and is leading the CAD laboratory() at Ajou University. He worked at Clausthal University of Technology (Germany) as a visiting researcher and the University of Wisconsin-Madison (USA) as a postdoctoral associate. He obtained his Ph.D. in mechanical engineering in 2004 at KAIST. His current research interests are product data quality (PDQ), VR application in product design, product data management (PDM), knowledge-based design system, and STEP. Peom Park is a professor in the Department of Industrial & Information Systems Engineering and is leading the Human Technology Research Center and Human Factors/HCI laboratory () at Ajou University. He worked on HCI and Telecommunication system at ETRI as a senior researcher. He obtained his Ph.D. in Industrial and Manufacturing Systems Engineering at Iowa State University on 1992. His current research interests are uT applications, u-Healthcare/Telemedicine, Telematics and Ergonomic/Safety Design.     

Sharing product data of nuclear power plants across their lifecycles by utilizing a neutral model

Many public and private Korean organizations are involved during the lifecycle of a domestic nuclear power plant. Korea Plant Engineering Co. (KOPEC) participates in the design stage, Korea Hydraulic and Nuclear Power (KHNP) operates and manages all nuclear power plants in Korea, Doosan Heavy Industry and Construction Co. manufactures the main equipment, and a construction company constructs the plant. Even though each organization has its own digital data management system and obtains a certain level of automation, data sharing among organizations is poor. KHNP obtains drawings and technical specifications from KOPEC in the form of paper. This results in manual re-work of definitions, and errors can potentially occur in the process. In order to establish an information bridge between design and operation and maintenance (O&M) phases, a generic product model (GPM), a data model from Hitachi, is extended for constructing a neutral data warehouse and the Korean Nuclear Power Plant Information Sharing System (KNPISS) is implemented.     

Development of an analysis system for geometric contour error evaluation in ultra-precision machining for microlens arrays

A basic principle for acquiring precisely shaped machined parts is to create dense tool path data. However, as the density of tool paths increases, the volume of data increases. The significant increase in data consumes more memory and machining time. Therefore, the creation of tool path data of unlimited density is impractical. This paper proposes a contour error evaluation system. The system makes correct decisions based on the expected quality of a workpiece. Specifically, the user creates tool path data by calculating deviations in the contour in relation to variations in the intervals of the tool path. The user can create tool paths by adjusting the amount of tool path data within the desired quality level. Accordingly, before the start of the machining process, the user can predict any machining loss likely to result from the excessive amount of data created in the creation phase. In addition, the tool path data of the proposed system are experimentally compared with the actual shape of a part machined with a microlens array machining system.     

Establishment of an effective product liability prevention plan by analyzing product liability cases

The tightening of product liability (PL) law and the growth of consumer demand for product safety make PL a critical issue of business management. In this paper, we establish an effective PL prevention plan by analyzing representative PL cases in Korea, the United States, and Japan. We consider the type of product, the type of defect, the cause of defects, and the results of PL lawsuits. Most PL problems are due to manufacturing defects. Damage and defects are uniformly distributed over various types of products. The analysis results indicate that we should not be limited to issues of product safety. We should also consider a responsible PL prevention plan that can protect consumers from risk of damage. In preventing design defects, we should give special consideration to the technical and legal aspects of a design review so that we can improve the conventional prevention plans. Manufacturing defects should be prevented through a product safety review tailored to the product characteristics. Moreover, we endeavor to prevent instruction defects by analyzing the characteristics of the environment in which a product is used. Copyright © 2010 John Wiley & Sons, Ltd.     

Development of a feature-recognition and measurement path generation system based on NURBS surfaces for 5-axis on-machine measurement

Journal of Mechanical Science and Technology - On-machine measurement (OMM), which is used to measure the machined surfaces of a workpiece during or after the machining of the workpiece, enables...     

Reconstruction of primitive-shaped pipe elbows from a triangular mesh in ship outfitting model

Journal of Mechanical Science and Technology - Integration of heterogeneous computer-aided design (CAD) models into shipbuilding CAD systems is necessary during ship modeling in shipyards. Vendor...