• ETRI Journal
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• v.34 no.4
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• pp.503-510
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• 2012

We analyze the relationship between channel coherence bandwidth and two complexity-reduced lattice reduction aided detection (LRAD) algorithms for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems in correlated fading channels. In both the adaptive LR algorithm and the fixed interval LR algorithm, we exploit the inherent feature of unimodular transformation matrix P that remains the same for the adjacent highly correlated subcarriers. Complexity simulations demonstrate that the adaptive LR algorithm could eliminate up to approximately 90 percent of the multiplications and 95 percent of the divisions of the brute-force LR algorithm with large coherence bandwidth. The results also show that the adaptive algorithm with both optimum and globally suboptimum initial interval settings could significantly reduce the LR complexity, compared with the brute-force LR and fixed interval LR algorithms, while maintaining the system performance.

• Journal of Korean Society for Quality Management
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• v.25 no.4
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• pp.168-184
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• 1997

The primary objective of this paper is to develop an interactive computer graphic aided decision su, pp.rt system for the design of inspection plans for complex production systems. This research first develops a computer simulator, called Simulator for Inspection Systems(SIS), in order to represent the production system as a network model. The simulator elicits fundamental information about the system from the decision maker(DM) in an interactive manner. A decision su, pp.rt system is then proposed by combining SIS and Compromise Programming. The system simulates a set of possible inspection strategies implicitly, observes all the important measurements about the inspection system, and employs the compromise programming a, pp.oach to help the DM determine the best compromising allocation of inspection effort considering his/her preferences. Finally, the performance of the proposed system is evaluated using two test cases. The pros and cons of the system are also discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.623-624
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• 2006

Over the past decade, changes in product development processes and increased consumer demands have dramatically influenced engineering working practices and targets. The information technology revolution has made its appearance concurrent to this relentless escalation in product engineering requirement. It has offered hopes for improved productivity despite these increasing demands. The wide availability of personal computing power, virtually inexhaustible sources of information and an abundance of computerized engineering tools have created great expectations. CAPP (Computer Aided Process Planning) Expert system and database were developed using VB.NET and Microsoft SQL 2000 Server.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.25-28
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• 2002

This paper is concerned with the design of roller profiles in tube/pipe straightener with both methods of Computer Aided Design and Computer Aided Engineering. Design analysis is carried out from two point of view. The one is the research in the minimization of tube pitch which was very important factor in levelling process. In order to minimize tube pitch, profiles of the roller were calculated so that the contact region between roller and tube was maximized. The other is determination of an optimum amount of intermesh for the proper progress without a jam in levelling process. Generally the jamming trouble was casued by excessive amount of intermesh in levelling process. The optimum amount of intermesh was determined through the finite element analysis.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1097-1098
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• 2006

This study investigated the needs and effectiveness of the application of Computer-Aided Systems Engineering Tool in order to enhance the chance of success of the large and complex system development projects like City Train System. Furthermore, it was shown that the merits of Systems Engineering and Project Management must be complementary to each other in their interaction in a project. Especially, for the project plans must be executed based on the fully understood system being developed, the technical and management data of the system development need be integrated and be able to support exact and rapid decision making of project planning. As an alternative solution approach, a model for development knowledge capture integrating both technical and management data of system development was proposed using Computer Aided Systems Engineering tool-Cradle.

• Electronics and Telecommunications Trends
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• v.11 no.1 s.39
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• pp.49-64
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• 1996

Computer-Aided Control Engineerig(CACE) 프레임워크는 컴퓨터 제어시스템의 개발비용과 신뢰성에 대한 위기에 대처하여, 제어시스템 엔지니어링 분야의 독립적인 소프트웨어 패키지들을 상호 호환성 있게 통합하여 컴퓨터 제어시스템의 모델링과 구현, 유지보수 및 소프트웨어 재사용에 이르는 라이프사이클 전단계에 걸쳐 일관적으로 사용될 수 있어야 한다. 이러한 개념의 개방형 통합 소프트웨어 패키지 운영체제가 광범위한 응용분야에서 재사용될 수 있도록 하기 위해서는 다음과 같은 5가지 서비스 클래스를 제공하는 프레임워크라는 기반구조에 의해 개발되어야 한다. 프레임워크에서 제공하려는 서비스들은 여러 응용분야의 소프트웨어 패키지들을 통합적으로 운영하기 위하여 필수적으로 요구되는 서비스 개념으로서 데이터베이스 서비스, 모델정의 서비스, 태스크 운영 서비스, 사용자 대화 서비스, 프로세스 통신을 위한 메시지 서비스들이 존재한다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.5
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• pp.15-23
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• 2003

A feature-based inspection planning system is proposed in this research to develop more efficient measuring methodology for the OMM(On-Machine Measurement) or CMM(coordinate Measuring Machine) for complicated workpiece having many primitive form features. This paper is proposed solution that optimum inspection sequence of the objective features. The sequences are determined by analyzing the feature information such as the nearest relationship and the possible probe-approach direction(PAD) of the features, and forming feature groups. A series of heuristic rules are developed to accomplish it. Also, each feature is decomposed into its constituent geometric elements for inspection process, and then the number of sampling points, location of the measuring points, optimum probing path are determined.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.353-358
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• 2002

A feature-based inspection planning system is proposed in this research to develop more efficient measuring methodology for the OMM (On-machine measurement) for complicated workpiece having many primitive form features. This paper focuses on the development of the CAIP (computer-aided inspection system) methodologies. The optimum inspection sequences for the features are determined by analyzing the feature information such as the nested relations and the possible probe approaching directions of the features, and forming feature groups. A series of heuristic rules are developed to accomplish it. Also, each feature is decomposed into its constituent geometric elements, and then the number of sampling points, the locations of the measuring point, the optimum probing path are determined by applying the fuzzy logic, Hammersley's method, and the TSP algorithm. To verify the proposed methodologies, simulations are carried out and the results are analyzed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.4
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• pp.551-561
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• 1999

본 논문에서는 쉘 최적화에 대한 연구 결과를 기술하였다. 본 연구의 주목적은 쉘 구조물의 최적형상과 두께 분포를 찾는데 있다. 쉘의 변형에너지를 목적함수로 사용하고 초기 쉘의 부피를 제약조건을 고려하였다. 본 연구에서는 Computer-Aided Geometric Design (CAGD) 기법을 이용하여 쉘의 형상과 그 두께 분포를 표현하였고 쉘의 변형에너지를 측정하기 위해서 가변형 도를 채용한 퇴화 쉘 요소(Degenerated Shell Element)를 도입하였다. 최적 값을 구하기 위해서 세 가지 수학적 프로그래밍 기법을 제공하는 프로그램 DOT를 사용하였다. 마지막으로 새로이 개발된 쉘 최적화시스템의 효율성을 최적화예제로써 증명하였다.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.104-109
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• 1994

This research describes some developments of computer-aided process planning and die design for hot forging products of H-shaped plane strain produced by the press. The system is composed of three main modules(process planning module, die design module and simulation module) which are used independently or in all. Systm capabilities include as follows: 1. In die design module, using the results of process planning module, the shape and size of bolcker and finish die in each operation are determined and the ouput id generated in graphic form for manufacturing drawing. 3. In simulation module, the flow pattern of workpiece and the load/stroke curve are approximately predicted. Design rules for process planning and die design are extracted from plasticity theories, handbooks, relevant references and empirical know-how of field experts in hot forging companies. The developed system provides poweful capabilities for process planning and die design of hot forging products.