• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.138-141
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• 2006

This paper considers a two-machine flow-shop scheduling problem for minimizing mean flow time. Each job has three non-preemptive operations, where the first and third operations must be Processed on the first and second machines, respectively, but the second operation can be processed on either machine. A lower bound based on SPT rule is derived, which is then used to develop a branch-and-bound algorithm. Also, an efficient simple heuristic algorithm is developed to generate a near-optimal schedule. Numerical experiments are performed to evaluate the performances of the proposed branch-and-bound and the heuristic algorithm

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.243-248
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• 1992

Computer Integrated Manufacturing(CIM) is a growing technology as a solution for the total automation of a manufacturing system. However, the implementation in the shop floor is extremely difficult due to many reasons. Flexible Manufacturing System (FMS) is usually considered as a solution for the shop floor automation. One of the difficulties in FMS is the communications problem. Since various machinaries with different communications protocols are included, applying a unified scheme is almost impossible. Therefore, a systematic approach is a key point to solve the communication problem. A cell is defined as an automation unit where closely related for a job reside together. A cell is a messenger between upper level computers and lower level machine equipment. In this research, the functions of the cell are defined to have more capabilities than conventional cell since a cell can be often a total manufacturing system in a small to medium sized factory. The cell conducts communications with different machines through the communications schemes established here. A set of software system has been developed according to the defined communications. The software has been tested for a simulation and real experiments for proof.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.1
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• pp.69-74
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• 2004

A sequencing problem is to find an ordered sequence of some entities which maximizes (or minimize) the domain specific objective function. As some typical examples of sequencing problems, there are traveling salesman problem, job shop scheduling, flow shop scheduling, and so on. This paper introduces a new type of sequencing problems, named a sequencing problem with fuzzy preference relation, where a fuzzy preference relation is provided for the evaluation of the quality of sequences. It presents how such a problem can be formulated in terms of objective function. It also proposes a genetic algorithm applicable to such a sequencing problem.

• Culinary science and hospitality research
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• v.22 no.4
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• pp.222-239
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• 2016

This study is composed of both a research of research literature and empirical analysis. With regard to literature based, consideration was given to present conditions of domestic coffee shops, thhe definition of barista, the duty characteristics baristas, and intention to change job. Empirical analysis established hypotheses and verified the effect of duty characteristics on job satisfaction and turnover intention. A survey to verifying the hypothesis of study was performed for 400 baristas who were working at their coffee shops with selecting coffee shops randomly in Seoul and Kyeonggi-do. 2012.08.15~2012.08.30, for 15 days, I performed survey, without faithless answers and questionnaires which weren't written, I used total 331 papers for actual analysis. Collected basic data were analyzed through SPSS 18.0 program by frequency analysis, correlation analysis, factorial analysis, reliability analysis, regression analysis, and so on. I suggested like this for managing effective human resources. For increasing satisfaction of duty of barista, manager should give opportunity for attending important duty to barista, and because of this, barista can feel sense of responsibility and self-esteem.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.353-363
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• 2012

Purpose: To establish basic data for effective clinical practice program by investigating the clinical practice importance and needs for ophthalmic optics students and optical shop owners. Methods: 263 students and 100 optical shop owners who had experience in clinical practice were surveyed in importance and needs of clinical practice and analyzed the results. Results: In general importance for clinical practice, realized the optician's job aptitude $4.29{\pm}0.72$ was highest among students and understanding the work of optician $4.48{\pm}0.52$ was highest among shop owners. Importance of specific duty for clinical practice, communication strategy & customer service was highest in both students $4.46{\pm}0.70$ and shop owners $4.18{\pm}0.86$ each. Importance of time & optical shop for clinical practice, supportive guide and education by opticians & shop owner was highest in both students $4.53{\pm}0.66$ and shop owners $4.35{\pm}0.59$ each. Importance of school support for clinical practice, administrative support for optical shop and students was highest among students $4.10{\pm}0.78$ and orientation from the school before clinical practice $3.98{\pm}0.68$ was highest among shop owners. In general needs for clinical practice, expanding the clinical practice field $4.43{\pm}0.73$ was highest among students and needs of clinical practice in the curriculum $4.39{\pm}0.65$ was highest among shop owners. Needs of specific duty for clinical practice, spectacle fitting $4.40{\pm}0.71$ was highest among students and ophthalmic dispensing $4.12{\pm}0.83$ was highest among shop owners. Conclusions: For effective clinical practice, clinical practice program should be develop which is reflecting the importance and needs of students and optical shop and also cooperation and interest of school and optical shop are required.

• Journal of Fashion Business
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• v.16 no.4
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• pp.186-199
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• 2012

Most of employees in service area frequently and strongly experience job-stress caused by emotional labour than in general. This job-stress is supposed to incur employees' burn-out, which burn-out brings a lower service quality in various aspects of physical and spiritual hospitality. The purpose of this study is to identify the impacts of burn-out on emotional labour of hair designer, with 155 primary data from a sample of 200 employees of hair shop in Seoul and Gyeongnam area. The reliability and validity of the collected data were checked through the calculation of Cronbach's ${\alpha}$ and factor analysis. The empirical research made by regression analysis confirms that emotional labour significantly has a negative effect on burn-out of hair designer. Therefore, hypothesis presented to mediate the effect of burn-out on emotional labour of hair designer was supported in positive. Hopefully, this study contributes to hair business shops for setting up a management strategy on effective job-satisfaction of hair designer.

• Management Science and Financial Engineering
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• v.3 no.2
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• pp.29-43
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• 1997

Many heuristics have been developed in order to overcome the computational complexity of job shop problems. In this research, we develop a new heuristic by selecting four simple dispatching rules, i.e., SPT, LPT, SR and LR, dynamically as scheduling proceeds. The selection is accomplished by using artificial neural networks. As a result of testing on 50 problems, the makespan obtained by our heuristic is, on the average, 13.0% shorter than the longest makespan, and 0.4% shorter than the shortest makespan obtained by existing dispatching rules.

• Journal of the Korea Society for Simulation
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• v.3 no.1
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• pp.1-16
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• 1994

In this paper, the modeling capabilities of an object-oriented simulator, AgvTalk is demonstrated by designing and simulating a conceptually configuration of AGV systems, known as the tandem configuration. The characteristics and design methodology in AgvTalk are described between the tandem configuration for AGV systems and conventional AGV systems. Also, simulation between the conventional AGV system and its corresponding tandem AGV system are compared with AgvTalk in the job shop environment. From the simulation results, the characteristics of each system observed are discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.353-359
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• 1993

본 연구에서는 객체지향 개념과 분산형 문제해결 방법의 장점을 혼합한 FMS 생산현장통제 시스템을 제안하였다. 제안된 시스템은 FMS의 모든 구성요소를 지능적인 객체로써 표현하고, 객체들간의 Bidding 과정을 통하여 생산 현장의 상태변화에 대응해 나가는 구조를 가지고 있다. 실험 결과, 제안된 시스템은 기존의 Dispatching rule에 비하여, job의 시스템내 체류시간이 감소하며 기계부하가 평준화되는 현상을 나타내었다.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.482-487
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• 1991

The scheduling algorithm based on the hierarchical scheduling policy is presented for the Job Shop type FMC control, and the simulation results using this hierarchical scheduling policy are with the results which are based on the heuristic scheduling policy. The results show that the hierarchical ling policy is more efficient than the heuristic scheduling policy in either case that there exist machine failures in the FMC or not.