• 소성∙가공
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• 제14권7호
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• pp.613-618
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• 2005

The paper is concerned with the process design and the die design for manufacturing the preform of a large pressure vessel. The cold-working processes are introduced to improve the fatigue strength and to simplify the manufacturing process. By the finite element simulation, the parameter design is carried out, which is subjected to constraints such as the blank sire, press capacity and other minor limitations. The proposed design results are verified by the model experiments, in which the model is scaled down to one tenth of the original size.

• 산업경영시스템학회지
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• 제23권61호
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• pp.137-146
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• 2000

One of the problems faced in implementing cellular manufacturing systems is machine-part group formation. This paper proposes machine-part grouping algorithms based on Self-Organizing Map(SOM) neural networks and K-Means algorithm in cellular manufacturing systems. Although the SOM spreads out input vectors to output vectors in the order of similarity, it does not always find the optimal solution. We rearrange the input vectors using SOM and determine the number of groups. In order to find the number of groups and grouping efficacy, we iterate K-Means algorithm changing k until we cannot obtain better solution. The results of using the proposed approach are compared to the best solutions reported in literature. The computational results show that the proposed approach provides a powerful means of solving the machine-part grouping problem. The proposed algorithm Is applied by simple calculation, so it can be for designer to change production constraints.

• 대한산업공학회지
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• 제19권4호
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• pp.41-48
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• 1993

Prime advantage of flexible manufacturing systems(FMS) is a flexibility. Flexibility is expected to prolong the service life of a manufacturing facility and enable it to respond quickly and economically to dynamic market change. The FMS loading decision is concerned with the allocation of operations and tools to machines subject to technological and capacity constraints of the system. Modern FMS loading problem has the multiple objectives such as processing cost, time and work load balance. We propose multi-objectives which could be used to formulate the loading/routeing problem and sequencing decision which should be adopted for each part type in order to maximize the machine flexibility by Hamming distance matrix based on Incidance matrix. Finally, a numerical example is provided to illustrate the proposed model.

• 대한산업공학회지
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• 제9권1호
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• pp.23-31
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• 1983

A group scheduling problem, which is production scheduling problem associated with the concept of group technology, is studied under due date constraints in multi-stage manufacturing systems. The purpose of this paper is to develop and evaluate a practical heuristic procedure for determining group sequence and job sequence within each group to minimize total tardiness in multi-stage manufacturing systems. A heuristic algorithm has been developed by introducing the concept of relative measures of job tardiness and group tardiness for job sequencing and group sequencing, respectively. A numerical example is shown to illustrate the proposed procedure. The heuristic algoirthm is tested by comparisons with problems with known optimal solutions and also with random group schedules for a set of large-size problems. Results indicate that the proposed heuristic algorithm provides good solutions with small computational requirements, and thus is viable for large size problems in practice.

• Industrial Engineering and Management Systems
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• 제11권3호
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• pp.224-232
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• 2012

The paper proposes a non-parametric methodology, data envelopment analysis, for measuring efficiency and productivity in service delivery systems with capacity constraints. The methodology provides allocation approaches for studying behaviors of firm and customers in service delivery strategy. The experimental study is carried out to investigate allocation behaviors and conduct an objective tradeoff between efficiency approach and productivity approach. The experimental result indicates that the efficiency approach allocates resource via maximizing customer efficiency rather than firm productivity as in the productivity approach. Moreover, the experiment reveals that there exists an objective tradeoff between the efficiency approach and the productivity approach. These findings provide strategic options for allocation policy in service delivery systems.

• 산업공학
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• 제13권4호
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• pp.564-571
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• 2000

Manufacturing companies are implementing a so-called customer-centered supply chain management to have a competitive advantage. In these efforts, collaboration not only within a company but also with suppliers, partners and customers is emphasized. The fast delivery, reducing the total lead-time from development to delivery, is pursued more than ever, though the quality and cost are still importantly regarded. Die manufacturing companies are not exception from these trends, because a die is a necessary tool for almost manufacturing industries. The planning and scheduling system plays an important role in supply chain management. In this study, we address a scheduling problem of a die manufacturing company. The problem is very complex due to many reasons including the uncertainty in environment and the complexity of constraints. Considering the importance of due-date satisfaction and human planners' roles, we designed the solution algorithm and the user interface respectively. In the implementation phase, modeling constructs and basic solution algorithms of ILOG solver and ILOG scheduler are used. In the paper, the problem and the algorithm are described with ILOG constructs, and the experience of use is also addressed.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제3권9호
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• pp.335-340
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• 2014

Crowd Sourcing 기반의 Social App Manufacturing 환경에서는 소규모 앱 개발 프로젝트를 익명의 가상팀에 의해 시공간의 제약이 없이 수행하며 이를 위해 앱 개발 관리를 위한 자동화된 방법을 필요로 한다. Social App Manufacturing의 특징인 익명성을 갖는 가상팀은 프로젝트 진행 상황에 대한 가시성의 저하와 프로젝트 완료 여부의 불확실성을 증가시키는 핵심 요인이다. 본 연구에서는 Social App Manufacturing 환경하의 프로젝트 관리 방법의 하나로 개발 지연이 프로젝트에 주는 위험 영향을 정량적으로 측정할 수 있는 위험영향도 측정 모델을 제안한다. 제시한 측정 모델은 작업일정 지연에 따른 위험 영향 유형과 위험영향도 특성함수를 정의하고 진행 성과에 따른 프로젝트 위험영향도 측정식을 제안한다. Social App Manufacturing 환경에서 수행하는 프로젝트 관리에 이 모델을 활용하여 진행 상황에 대한 가시성을 확보하고 일정 지연으로 실패 위험이 발생하는 프로젝트를 식별하고 미리 대처할 수 있도록 한다.

• Journal of Platform Technology
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• 제12권2호
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• pp.3-11
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• 2024

제4차 산업혁명으로 촉발된 디지털 전환과 비대면 서비스의 증가라는 흐름 속에서 클라우드 컴퓨팅 서비스에 대한 수요가 가파르게 촉진되고 있다. 현재 클라우드는 공공, IT, 금융 등 다양한 산업 분야에 도입되고 있으며, 제조산업 역시 미래 지속가능성 확보를 위하여 클라우드를 도입, 스마트 제조를 통한 혁신을 추진하고 있다. 하지만 제조기업이 클라우드를 도입하는 데는 보안 우려사항으로 인한 제약이 존재하는 것으로 나타났다. 클라우드 보안위험을 확인한 기존 연구는 제조산업을 고려했다기 보다는 일반적인 클라우드 보안위험이나 기술적 보안위험을 중심으로 클라우드 보안위험을 제시한 한계가 있었다. 이에 본 연구는 제조산업 현장에서 실제 우려하는 사항을 바탕으로 제조산업 클라우드 보안위험을 분석하고자 하였다. 이를 위해 전문가 인터뷰와 문헌조사를 시행해서 제조산업 클라우드 보안위험을 새롭게 식별하였으며, 선정된 보안위험에 대하여 설문조사를 통해 적합성과 시급성을 검증했다. 본 연구를 기반으로 향후 제조산업 클라우드 보안관리 체계가 설계된다면, 제조산업의 클라우드 도입이 보다 활성화될 것으로 기대한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.219-224
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• 2002

This paper aims to derive a mathematical model of the dynamics of handling tasks in robot finger which stable grasping and manipulates a rigid object with some dexterity. Firstly, a set of differential equation describing dynamics of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. Secondly, problems of controlling both the internal force and the rotation angle of the grasped object under the constraints of area-contacts of tight area-contacts are discussed. The effect of geometric constraints of area-contacts on motion of the overall system is analyzed and a method of computer simulation for overall system of differential-algebraic equations is presented. Thirdly, simulation results are shown and the effects of geometric constraints of area-contact is discussed. Finally, it is shown that even in the simplest case of dual single D.O.F manipulators there exists a sensory feedback from sensing data of the rotational angle of the object to command inputs to joint actuators and this feedback connection from sensing to action eventually realizes secure grasping of the object, provided that the object is of rectangular shape and motion is confined to a horizontal plane.

• The Journal of Asian Finance, Economics and Business
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• 제8권12호
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• pp.129-139
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• 2021

The aim of this study is to provide insight into tax avoidance through planning and management, and its investment consequences in financially constrained and unconstrained firms, as well as to empirically examine the interrelationships between the variables studied. Data was extracted from the financial statement analysis of non-financial companies listed on the Pakistan stock exchange (PSX) published by the State Bank of Pakistan, covering ten major manufacturing sectors. KZ index and WW index are used to identify financially constrained and unconstrained firms. Tax avoidance is measured by using GETR and LETR. All the equations are estimated through panel data regression models using common, fixed, and random effects. The empirical investigation of the role of tax avoidance in all firms collectively and constrained and unconstrained firms separately showed that the tax avoidance behavior of these firms is translated into investments by these firms. The study will help policymakers in strategy formulation and implementation related to tax planning and investment decisions in constrained and unconstrained firms to overcome their financial constraints and to optimize their investment decisions for value maximization. This will substantially increase the investment in the country by providing growth opportunities and lowering the tax rates.