• Geomechanics and Engineering
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• v.12 no.2
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• pp.269-294
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• 2017

This study aimed to realize the creation of fuzzy stochastic damage to describe reliability more essentially with the analysis of harmony of damage conception, probability and fuzzy degree of membership in interval [0,1]. Two kinds of fuzzy behaviors of damage development were deduced. Fuzzy stochastic damage models were established based on the fuzzy memberships functional and equivalent normalization theory. Fuzzy stochastic damage finite element method was developed as the approach to reliability simulation. The three-dimensional fuzzy stochastic damage mechanical behaviors of Jianshan mine slope were analyzed and examined based on this approach. The comprehensive results, including the displacement, stress, damage and their stochastic characteristics, indicate consistently that the failure foci of Jianshan mine slope are the slope-cutting areas where, with the maximal failure probability 40%, the hazardous Domino effects will motivate the neighboring rock bodies' sliding activities.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.3
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• pp.27-43
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• 1991

연소 가공은 고품질 고정도를 필요로 하는 경우 매우 유효한 가공방법이지만 그 공정이 많은 Parameter에 의해 구성되기 때문에 동일한 조건에서도 정량적인 평가가 어려우므로 작업현장 에서는 과학적 원리와 공학적 지식 보다는 숙련자의 경험과 기능에 의존하고 있는 실정이다. 본 연구에서는 이와 같은 국면에 대처한 문제 해결을 위해 Computer가 인간사고에 근접 할 수 있도록 Fuzzy 이론과 Default 이론을 도입하고 전문가의 이론적 지식과 숙련자의 감각적 지식을 적극 수용 하여 연소용 Expert system (최적 가공 조건의 설정 System과 Trouble shooting system)을 개발하였다. 또한 연소 가공 Data의 불확실한 애매성을 효과적으로 이용 할 수 있도록 Fuzzy 가능성이론에 의해 가공 Datad을 회귀 분석하여 실가공 Data base에 축적시켜 재활용토록 설계하었으며 개발된 본 System 의 실행 결과 그 활용성이 높음을 입증하였다.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.59-65
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• 1996

A major problem in automation of turning operations is the difficulty in obtaining a sufficient and reliable chip control. Therefore it becomes desirable to find a method which can detect the chip form. Newly born chips in usual metal cutting radiate infrared rays. When such chips run out of cutting point quickly, the radiated energy from the zone around the tool is low compared with that of the case when long tangled chips are staying around the tool. The difference in chip pattern can be detected from the output of pyrometer. But, strictly speaking, only the output of pyrometer does not identify the chip form because that is the removal of chip. Therefore, in this paper, a method of the identification of chip form using output of pyrometer and fuzzy inference is developed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.164-169
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• 1998

This paper deals with condition monitoring for tool wear during tuning operation. To develop economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique are proposed. To identify noise sources of tool wear and reject background noise, noise rejection methodology is proposed. features to represent condition of tool wear are obtained through analysis using adaptive filter and FFT in time and frequency domain. By using fuzzy pattern recognition, we extract features, which are sensitive to condition of tool wear, from several features and make a decision on tool wear. The validity of the proposed system is condirmed through the large number of cutting tests in two cutting conditions.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.1898-1909
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• 1993

In this paper, a convenient scheme for solving multi-objective optimization problems including fuzzy information in both objective functions and constraints is presented. At first, a multi-objective problem is converted into single objective problem based on the norm method, and a merbership function is constructed by selecting its type and providing the parameters defined by the norm method. Finally, this fuzzy programming problem is converted into an ordinary optimization problem which can be solved by usual nonlinear programming techniques. With this scheme, a designer can conveniently obtain pareto optimal solutions of a fuzzy system only by providing some parameters corresponding to the importance of the objectiv functions. Proposed scheme is simple and efficient in treating multi-objective fuzzy systems compared with and method by with membership function value is provided interactively. To show the validity of the scheme, a simple 3-bar truss example and optimal cutting problem are solved, and the results show that the scheme is very useful and easy to treat multi-objective fuzzy systems.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.172-179
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• 1996

This paper described the application of fuzzy multiobjective linear programming to solving a multiple-use problem of forest resources management. At first the concepts of linear programming, fuzzy linear programming and fuzzy multiobjective linear programming were introduced briefly. In order to illustrate a role of fuzzy multiobjective linear programming in the process of multiple-use forest planning, the natural recreation forest in Mt. Yoomyung was selected for this study. A fuzzy multiobjective linear programming model is formulated with data obtained from this Mt. Yoomyumg natural recreation forest to solve the multiple-use management planning problem of forest resources. Finally, the results, which were obtained from the calculation of this model, were discussed. The maximal value of the membership function(${\lambda}$) was 0.29, when the timber production and the forest recreation function were optimized at the same time through the fuzzy multiobjective linear programming. The cutting area in each period was 102.7ha, while total cutting area was 410.8ha for 4 periods. During 4 periods $57,904m^3$ will be harvested from this natural recreation forest and at the same time total visitors were estimated to be about 8.6 millions persons.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.214-222
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• 2003

Studies on the optimization of machining process can be divided into two different approaches: off-line feedrate scheduling and adaptive control. Each approach possesses its respective strong and weak points compared to each other. That is, each system can be complementary to the other. In this regard, a combined system, which is a feedrate control system fur cutting force optimization, was proposed in this paper to make the best of each approach. Experimental results show that the proposed system could overcome the weak points of the off-line feedrate scheduling system and the adaptive control system. In addition, from the figure, it can be confirmed that the off-line feedrate scheduling technique can improve the machining quality and can fulfill its function in the machine tool which has a adaptive controller.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1382-1385
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• 1993

In order to improve productivity, an intelligent control system is presented in the pater. In this intelligent control system, a feedforward neural network and a fuzzy feedback mechanism are adopted to achieve a constant milling force with an adjustable feedrate under a variety of cutting conditions in milling operations.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.123.3-123
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• 2001

To recycle the uranium resources in the spent nuclear fuels, all the fuel rods are extracted from the spent fuel assemblies. The remaining components of the spent fuel assembly after extracting all the rods, so called a NFBC(Non-Fuel Bearing Components), should be compacted to minimize the waste volume. To this present, KAERI (Korea Atomic Research Institute) has developed he NFBC compactor by introducing a new concept of cutting and compaction, In this paper, to achieve he maximum compaction ration of the NFBC volume while reducing compactor size, an fuzzy controller, which determines the reference force of the compactor, is proposed with using he fuzzy-inference.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.2
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• pp.127-132
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• 2001

In turning, the chip may be produced in the form of continuous chip or discontinuous chip. The continuous chips are dangerous to the operator and difficult to be handled at high speed machining. The signal of AE(Acoustic Emission) is found out to be related to cutting conditions, tool materials, test conditions and tool geometry in turning. In this study, the relationship between AE signal and chip form was experimentally investigated. The experimental results show that the types of chip form are possible to be classified from the AE signal using fuzzy logic.