• 제목/요약/키워드: Just-in-Time job

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다수의 경쟁이 존재하는 환경에서 적시 스케줄링에 관한 연구 (Just-in-time Scheduling with Multiple Competing Agents)

  • 정대영;최병천
    • 한국경영과학회지
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    • 제37권1호
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    • pp.19-28
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    • 2012
  • We consider a multi-agent scheduling problem such that each agent tries to maximize the weighted number of just-in-time jobs. Two objectives are considered : the first is to find the optimal solution for one agent with constraints on the other agents' weight functions, and the second is to find the largest set of efficient schedules of which corresponding objective vectors are different for the case with identical weights. We show that when the number of agents is fixed, the single machine case with the first objective is NP-hard in the ordinary sense, and present the polynomial- time algorithm for the two-machine flow shop case with the second objective and identical weights.

Analysis of Feedback Queues with Priorities

  • Hong, Sung-Jo;Hirayama, Tetsuji
    • 대한산업공학회지
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    • 제19권4호
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    • pp.137-146
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    • 1993
  • We consider single server feedback queueing systems with priorities. In the model, there are J stations and job classes. Jobs of class i arrive at station i according to a Poisson process, and have a general service time distribution. We derive the generating functions of the number of jobs at each station just after a busy period and the formula for the mean sojourn time that a specific tagged job spends at station j from its arrival to departure from the system.

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JIT(Just-In-Time) 하의 작업스케쥴링을 위한 인공신경망 (An Artificial Neural Network for Job Scheduling under Just-In-Time Environment)

  • 김수영;이문규;윤찬균
    • 대한산업공학회지
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    • 제21권1호
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    • pp.3-16
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    • 1995
  • JIT manufacturing requires that materials and services should be done neither too early nor tardy. Therefore, related jobs have to be performed just-in-time. In this paper, we consider a problem of determining a schedule of jobs with a common due date. The objective is to minimize the squared deviation of complete times from the due date. An artificial neural network which is based on the mean field theory is proposed for the problem. Computational results obtained from computer simulations show that the network performs very well.

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A Study on Information System Improvement for Air Logistics SCM

  • Choi, Hyung-Rim;Park, Nam-Kyu;Lee, Hyun-Chul;Seo, Young-Joon;Shin, Joong-Jo
    • 한국정보시스템학회지:정보시스템연구
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    • 제14권3호
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    • pp.63-70
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    • 2005
  • Compared with land logistics and sea logistics, air logistics takes not only less transportation time, but also makes just-in-time delivery possible. Because of this, in spite of high freight rates, many shippers make good use of airlines. To cope with borderless competition in this global age, most shippers using air logistics want to receive diverse information including just-in-time cargo delivery and dangerous situation as well as convenience and speed in job handling. Nevertheless, most domestic forwarders, who perform many kinds of important businesses for air logistics, mainly put emphasis on demanding information from overseas partners through their business agreements, that is, focusing on horizontal integration, instead of sharing information or improving job performance among air logistics participants. As a result, it is almost impossible to satisfy the needs of shippers. Airline users want to remove the uncertainties over their cargo movement. And in time of emergency, they want to take immediate measures through speedy information sharing and decision-making. In order to satisfy shipper's needs, all the organizations participating in the air logistics supply chain-cargo senders, cargo receivers, forwarders, transporters, licensed customs brokers, airlines as well as foreign partners-have to set up a vertical cooperation system. For effective air logistics SCM, it is very important to remove overlapping jobs, strengthen the efficiency of job handling, and provide online monitoring on cargo information in order to support decision-making. To this end, this paper has applied the concept of RTE (Real Time Enterprise), a new business management system, which tries to maximize competitiveness by removing many hindrance factors on an ongoing basis in managing and fulfilling core business processes based on up-to-the-minute information. In order to realize RTE-based information system for air logistics SCM, this paper has analyzed the information required by business process and by air logistics participant, and suggested the method for information sharing, point of time for information input and output, and its means.

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작업치료사의 직무 스트레스에 관한 연구 (The Study of Job Stress in Occupational Therapist)

  • 양영애;허진강;노영만;이규창
    • 대한인간공학회지
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    • 제26권3호
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    • pp.1-9
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    • 2007
  • The purpose of this study was going to research relation of job stress and society psychologic stress according to general characteristic, work characteristic, health characteristic and personality characteristic for the occupational therapist in the working domestic rehabilitation therapy with hospital and welfare center occupational therapist. The research was 91 of withdrawal questionnaire among 102 occupational therapist from 1. November 2005 to 31. December 2005. In the result of analysis the given question for the ninety one occupational therapist showed just normal group 25% 23 person, potential stress group 47% 43 person, and the rest 28% 25 person high risk group. The result shows significance different in general characteristic of job stress about age, final scholarship and marriage. Job stress was included income, working time, office form and working position etc. Health special job stress was significance different according to sleep time. So we have to know a fact of job stress of occupational therapist and prevent of loss of business services. And we have to endeavoring removals factor of stress and good office culture fixation.

급식형태와 우리나라 영양사의 직무만족도의 관련성에 관한 연구 (Relationships Between Characteristics of Foodservice and Job Satisfaction of the Korean Dietitian)

  • 문현경;정효지;조정순
    • 대한지역사회영양학회지
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    • 제2권2호
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    • pp.232-245
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    • 1997
  • This study was carried out to investigate relationships between characteristics of foodservice and job satisfaction of Korean dietitians. The subjects were 2987 dietitians who responded to the questionnaire distributed at the annual education program of the Korean Dietetic As-sociation in 1995. The results were followings; 1)The level of jov satisfaction of Korean dietitians was low for payment work environment and value achievement as a dietitian while it was relatively high for the relationship with col-leagues. The other parts of job satissatisfaction such as work load work contents supervision by the superiors participation of policy decision and selp disccertion were just below average. 2)The type of operating style menu style and serving time in foodservise were not sig-nificantly related to all fields of job satisfaction but the kinds of meals served a day and the to-tal number of persons served a day were significantly correlated. 3) The dietitians who had to provide meal plans such as breakfast+dinner and + snack or all day serving had significantly lower job satisfaction in all fields. 4)Job satisfaction was significantly higher when the total number of persons served a day was between 500-700.(Korean J Community Nutrition 2(2) : 232~245, 1997)

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운동 강도가 손 안정성에 미치는 영향 (Effects of Exercise Intensity on Hand Steadiness)

  • 한승조;김선욱;구교찬
    • 산업경영시스템학회지
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    • 제36권1호
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    • pp.1-7
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    • 2013
  • This study is aimed to investigate the association between anaerobic-aerobic exercise intensity and hand steadiness. Hand steadiness is the decisive contributor to affecting the job performance just as in the rifle shooting and archery in sports and the microscope-related jobs requiring hand steadiness in industries. In anaerobic exercise condition hand steadiness is measured through hand steadiness tester having 9 different diameter holes after each subject exerts 25%, 50%, 75%, and 100% of maximum back strength. In aerobic exercise occasion it is evaluated at each time heart rate reaches 115%, 130%, and 145% of reference heart rate measured in no task condition after they do jumping jack. The results indicate that an increased intensity in both types of exercise reduces hand steadiness, but hand steadiness at 25% of maximum back strength and 115% of reference heart rate is rather greater than at no exercise. Just as the relation between cognitive stress and job performance has upside-down U form, so does the association of physical loading to hand steadiness, which means that a little exercise tends to improve hand steadiness in comparison with no exercise.

JIT 시스템 운용의 출발점 - Cellular 제조라인의 구축 (A Study on the Formation of Cellular Manufacturing Line for Construction JIT System's Basis)

  • 구일섭;신현표
    • 산업경영시스템학회지
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    • 제17권31호
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    • pp.43-48
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    • 1994
  • In an effort to become more competitive and cost efficient many companies have shifted from traditional job-shop production to production using group technology (GT) and cell manufacturing (CM). Cellular manufacturing is critical to implementing Just-in-Time (JIT) production which pointed out in the previous articles. and adopt the U-shaped cell which allows for entry at one end of the U and exist at the other. This paper looks at the availability of cellular manufacturing, by applying those concepts to the small and medium sized industry.

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중소기업을 위한 JIT 생산방식 : 생산계획(生産計劃)의 수립과 칸반의 운용(運用) (Production Planning and Kanban Operations in JIT Systems for Small Manufacturers)

  • 정남기;유철수
    • 산업공학
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    • 제5권2호
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    • pp.29-37
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    • 1992
  • An approach to Just-In-Time for small job-shop-type manufacturers is presented. This is aimed at those who understand the pull production system, however, cannot afford either swift changeover in workcenters or frequent delivery to customers. First, as a production planning technique, a lot-sizing model entitled Multilevel Least Total Cost Model(MLTCM) is developed; The production order quantities of each components be those requiremensts of the end item production lot. The contribution of MLTCM is shown via simulation. Then, a framework of the Kanban operations is designed; A Production Control Kanban is introduced as a communication tool with Production Kanban in a job-shop.

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국내 건축시공(建築施工) 전공교육(全功敎育)에 대한 건설현장(建設現場)의 인식(認識) 및 요구(要求)에 관한 연구(硏究) (Comparison of the required abilities in construction site between field managers and students)

  • 이학주;송재혁;서장우;강경인
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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    • pp.123-126
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    • 2008
  • The construction industry highly depends on each specialized manager which is essential to successful project. However, a new employee, who has just graduated from architectural engineering college, is requested additional education for 1~2 years such as On-the-Job-Training (O.J.T) to perform his/her professional job in construction site. It is wasteful for both construction company and the employee in terms of time and cost. The purpose of this paper is to investigate the required abilities and analyze the gap of demanded abilities between field managers and students. To collect data for analysis, questionnaire which uses Likert Scale has been performed to both parts. As a result, the analysis show that the graduate's abilities related to field experience get especially low degrees in compare with non-field experience factors. These results will contribute architectural engineering education in college to make more realized.

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