• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.880-884
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• 1995

Manufacturing environment is getting characterized by unstable market demand,short product life cycle and timebased competition. For adapting this environment,machine tools have to be further versatile functionally in order to reduce part's set-up time. Unlike existing manufacturing systems mainly to focus on part flow, it is important to control tool flow using fast tool change device and tool delivery device in parallel machines consisting of versatile machine tools, because complete operations on a part can be performed on one machine tool in a single machine set-up. In this paper, under dynamic tool allocation strategy to share tools among machine tools, we propose a real-time tool allocation and operation esequence model with an objective of minimizing flow time using autonomy and negotiation of agents in parallel machines

• International Journal of Precision Engineering and Manufacturing
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• 제3권3호
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• pp.82-89
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• 2002

The need of ultra-precision machine tools, which manufacture and machine the high precision parts used in computers, semi-conductors and other precision machines, has been increased over years. Therefore it is important to design the driving parts, which affect significantly on their performances. In this paper, the dynamic analyses on the belt-driven system were explored. Relation of the acoustical natural frequency and the tension of belt was derived and presented through experiments. Also, while the dynamic loads on motor system were changed, dynamic deflections were calculated through finite element analysis. Nonlinear characteristics of the bearings having an effect on the dynamic performance were studied and the belt connecting the motor (driving part) to spindle of a machine tool (driven part) was modeled as truss and beam elements fur simulations under various conditions, and a beam element model was verified to be more useful.

• 산업공학
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• 제2권2호
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• pp.15-24
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• 1989

When we design, plan, and schedule for group technology, the limitation on the machine cells and cell size may occur. The purpose of this study is to find machine cells and part families to minimize the exceptional elements, constraining both the number of machine cells and the cell size. To solve this problem, the algorithm extending Kusiak's p-median method is proposed. In the proposed algorithm, the method finding initial solution and reducing the number of constraints is presented for computational efficiency. The proposed algorithm is evaluated and compared with well-known algorithms for machine-part group formation in terms of the exceptional elements. An example is shown to illustrate the proposed algorithm.

• 연구논문집
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• 통권31호
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• pp.101-112
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• 2001

A Twisting machine is to twist yarns for improving yarn stiffness. After twisting yarns, the twisting machine is winding yarn at a bobbin. Traverse cam is main part of winding yarn part. In other to improve twisting machine performance and stability, improve traverse cam part. Original displacement curves of traverse cam has two problems. One is that displacement curve has a vertex point the other is that velocity curve is discontinue point. So that, in this paper proposes a modified displacement curves of traverse cam and new shape design method of the traverse cam using the relative velocity method[1]. The relative velocity method calculates the relative velocity of the follower versus the cam at a center of roller, and then determines a contact point by using the geometric relationship and the kinematical constraints. Finally, we present to compare two designed cam. One is designed using original displacement curves the other is using modified displacement curve.

• 산업경영시스템학회지
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• 제18권34호
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• pp.91-97
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• 1995

This paper presents a possible application of artificial neural network in CM system design. CM systems can be designed based on product lines, part characteristics or part routines. GT(Group Technology) which uses part characteristics to design cells is widely applied, however, the identification of the part-machine families is the fundamental problem in the design process. A heuristic procedure using SOFM which requires only part-machine incidence matrix is proposed in this research. Comparison studies on ZODIAC and ROC with SOFM model are done and the results are discussed and summarized in this paper.

• 지능정보연구
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• 제15권3호
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• pp.53-65
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• 2009

영한 기계번역에서 영어 단어의 품사결정은 번역할 문장에 사용된 어휘의 품사 모호성을 해소하기 위해 필요하다. 어휘의 품사 모호성은 구문 분석을 복잡하게 하고 정확한 번역을 생성하는 것을 어렵게 한다. 본 논문에서는 이러한 문제점을 해결하기 위해 어휘 분석 이후 구문 분석 이전에 품사 모호성을 해소하려 하였으며 품사 모호성을 해소하기 위한 CatAmRes 모델을 제안하고 다른 품사태깅 방법과 성능 비교를 하였다. CatAmRes는 Penn Treebank 말뭉치를 이용하여 Bayesian Network를 학습하여 얻은 확률 분포와 말뭉치에서 나타나는 통계 정보를 이용하여 영어 단어의 품사를 결정을 한다. 본 논문에서 제안한 영어 품사결정 모델 CatAmRes는 결정할 품사의 적정도 값을 계산하는 Calculator와 계산된 적정도 값에 근거하여 품사를 결정하는 POSDeterminer로 구성된다. 실험에서는 CatAmRes의 동작과 성능을 테스트 하기 위해 WSJ, Brown, IBM 영역의 말뭉치에서 추출한 테스트 데이터를 이용하여 품사결정의 정확도를 평가하였다.

• 산업공학
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• 제12권4호
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• pp.532-539
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• 1999

The first step to design a cellular manufacturing system is to make part-families and machine-cells. This process is called the machine-part grouping. This paper considers a machine-cell size when grouping machine-cells. By considering a machine-cell size, an unrealistically big size of machine-cell which may be caused by the chaining effect can be avoid. A heuristic algorithm which minimizes the number of inter-cell movement of parts considering a machine-cell size is presented. The effectiveness and performance of the proposed heuristic algorithm are compared with those of several heuristic algorithms previously reported. The comparison shows that the proposed heuristic algorithm is efficient and reliable in minimizing the number of inter-cell movement of parts and also prevents the chaining effect.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.838-841
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• 2000

To improve the accuracy of products and improve the product quality, we need to enhance the machining accuracy of the machine tools. To this point of view, measurement and inspection of finished part as well as error analysis of machine tools has been studied for last several decades. OMM(On the Machine Measurement) has been issued to alternate with CMM, pointing out disadvantages of high expenses and lots of setting time in CMM. In this paper, we study 1) the spherical surface manufacturing by volumetric error compensation of machine tool, 2) the system development of OMM without detaching work piece from a bed of machine tool after working. 3) the generation of the finished part profile by On the machine measurement. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.46-51
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• 2002

A grinding technology is very essential to finish the surface of IT and BT industrial application parts such as wafer, optical connection part and lenses etc. However the finding machine has bead depended on imports. Especially, it is completely imported for machining high precision part relevant to domestic electric and communicational industries. The amount to import grinding machine is about $110milions. It takes about 35% of total import amount of all the machine tools. A domestic finder manufacturer is a very small-scaled bussinessman and research facilities is poor. Recently, it is increasing to demand high speed and precision grinding technology because it brings cost down and value added up. Its further study will be something related to inteligent grinding system fur value added and high precision part. It will make domestic grinding technology to its advanced country level.

• International Journal of Precision Engineering and Manufacturing
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• 제4권2호
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• pp.71-76
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• 2003

A virtual machine tool (VMT) is presented in this two-part paper. In Part 1, the analytical foundation for a virtual machining system is developed, which is envisioned as the foundation for a comprehensive simulation environment capable of predicting the outcome of cutting processes. The VHT system undergoes "pseudo-real machining", before actual cutting with a CNC machine tool takes place, to provide the proper cutting conditions for process planners and to compensate or control the machining process in terms of the productivity and attributes of the products. The attributes can be characterized by the machined surface error, dimensional accuracy, roughness, integrity, and so forth. The main components of the VMT are the cutting process, application, thermal behavior, and feed drive modules. In Part 1, the cutting process module is presented. When verified experimentally, the proposed models gave significantly better prediction results than any other methods. In Part 2 of this paper, the thermal behavior and feed drive modules are developed, and the models are integrated into a comprehensive software environment.vironment.