• 대한산업공학회지
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• 제37권2호
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• pp.132-143
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• 2011

This paper deals with a coal supply planning problem for power plants. We propose a mathematical optimization model to make decisions for coal pile sections, movement of reclaimers, and operation time of conveyor belts. The objective of the proposed model is to minimize the total operation time of conveyor belts and total movement time of reclaimers. The algorithm firstly selects a pile section by considering both the location of reclaimers and the stock amount on that pile section. And then the shortest path from the selected pile section has to be put into the operation schedule and check whether the total operation time is satisfied. Then finally the new schedule is updated. To this end, we have tested the proposed algorithm comparing with the general standard optimization package for the simplified problem SCSPP. From the numerous test runs for comparing with the existing coal supply scheduling methods, We see that the proposed model may improve the coal supply operation by reducing significant coal supply costs.

• 한국건설관리학회논문집
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• 제4권1호
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• pp.106-113
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• 2003

건설 프로젝트의 자원관리는 공사원가의 절감, 건축물의 공정 및 품질확보에 직접적으로 관계되어 이외의 공사관리요소와 함께 매우 중요한 요소를 차지하고 있다. 하지만 자원소요계획은 공사초기에 수립되고 고려요소가 다양하여 전사적 차원의 자원소요계획을 수립하기에는 한계가 있고, 관리자간의 정보단절로 실적정보관리가 불가능하다. 건설공사의 유기적 관리를 위해서는 각 관리요소의 체계적 구성이 필요하며, 각 관리간의 사업수행정보와 실적자료의 주기적인 갱신으로 이루어져야 한다. 이에 현장변동상창을 반영하고 효과적인 자원소요계획을 수립하기 위해서는 비용 일정 통합관리의 실적 데이터를 이용하여 자원소요량 산출근거를 명확히 하고, 효율적인 자원소요계획체계를 구성하여야 한다. 본 논문에서는 비용$\cdot$일정 통합관리를 이용한 자원소요량 산출방법을 제시하였으며, 비용$\cdot$일정 통합관리를 이용한 자원 조달관리 업무프로세스를 분석하여 체계적인 자원소요계획 체계를 마련하였다.

• Journal of Construction Engineering and Project Management
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• 제5권2호
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• pp.11-15
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• 2015

The Last PlannerSystem (LPS) has been implemented on construction projects to increase work flow reliability, a precondition for project performance againstproductivity and progress targets. The LPS encompasses four tiers of planning processes:master scheduling, phase scheduling, lookahead planning, and commitment / weeklywork planning. This research highlights deficiencies in the current implementation of LPS including poor lookahead planning which results in poor linkage between weeklywork plans and the master schedule. This poor linkage undetermines the ability of theweekly work planning process to select for execution tasks that are critical to projectsuccess. As a result, percent plan complete (PPC) becomes a weak indicator of project progress. The purpose of this research is to improve lookahead planning (the bridgebetween weekly work planning and master scheduling), improve PPC, and improve theselection of tasks that are critical to project success by increasing the link betweenShould, Can, Will, and Did (components of the LPS), thereby rendering PPC a betterindicator of project progress. The research employs the case study research method to describe deficiencies inthe current implementation of the LPS and suggest guidelines for a better application ofLPS in general and lookahead planning in particular. It then introduces an analyticalsimulation model to analyze the lookahead planning process. This is done by examining the impact on PPC of increasing two lookahead planning performance metrics: tasksanticipated (TA) and tasks made ready (TMR). Finally, the research investigates theimportance of the lookahead planning functions: identification and removal ofconstraints, task breakdown, and operations design.The research findings confirm the positive impact of improving lookaheadplanning (i.e., TA and TMR) on PPC. It also recognizes the need to perform lookaheadplanning differently for three types of work involving different levels of uncertainty:stable work, medium uncertainty work, and highly emergent work.The research confirms the LPS rules for practice and specifically the need to planin greater detail as time gets closer to performing the work. It highlights the role of LPSas a production system that incorporates deliberate planning (predetermined andoptimized) and situated planning (flexible and adaptive). Finally, the research presents recommendations for production planningimprovements in three areas: process related, (suggesting guidelines for practice),technical, (highlighting issues with current software programs and advocating theinclusion of collaborative planning capability), and organizational improvements(suggesting transitional steps when applying the LPS).

• 산업경영시스템학회지
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• 제40권2호
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• pp.111-120
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• 2017

This paper proposes an improved standard genetic algorithm (GA) of making a near optimal schedule for integrated process planning and scheduling problem (IPPS) considering tool flexibility and tool related constraints. Process planning involves the selection of operations and the allocation of resources. Scheduling, meanwhile, determines the sequence order in which operations are executed on each machine. Due to the high degree of complexity, traditionally, a sequential approach has been preferred, which determines process planning firstly and then performs scheduling independently based on the results. The two sub-problems, however, are complicatedly interrelated to each other, so the IPPS tend to solve the two problems simultaneously. Although many studies for IPPS have been conducted in the past, tool flexibility and capacity constraints are rarely considered. Various meta-heuristics, especially GA, have been applied for IPPS, but the performance is yet satisfactory. To improve solution quality against computation time in GA, we adopted three methods. First, we used a random circular queue during generation of an initial population. It can provide sufficient diversity of individuals at the beginning of GA. Second, we adopted an inferior selection to choose the parents for the crossover and mutation operations. It helps to maintain exploitation capability throughout the evolution process. Third, we employed a modification of the hybrid scheduling algorithm to decode the chromosome of the individual into a schedule, which can generate an active and non-delay schedule. The experimental results show that our proposed algorithm is superior to the current best evolutionary algorithms at most benchmark problems.

• 대한조선학회논문집
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• 제50권5호
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• pp.298-306
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• 2013

Nowadays, a transporter manager plans the schedule of the block transportation by considering the experience of the manager, the production process of the blocks and the priority of the block transportation in shipyard. The schedule planning of the block transportation should be rearranged for the reflection of the path blocking cases occurred by unexpected obstacles or delays in transportation. In this paper, the optimal block transportation path planning system is developed for rearranging the schedule of the block transportation by considering the damaged path. $A^*$ algorithm is applied to calculate the new shortest path between the departure and arrival of the blocks transported through the damaged path. In this algorithm, the first node of the damaged path is considered as the starting position of the new shortest path, and then the shortest path calculation is completed if the new shortest path is connected to the one of nodes in the original path. In addition, the data structure for the algorithm is designed. This optimal block transportation path planning system is applied to the Philippine Subic shipyard and the ability of the rapid path modification is verified.

• 산업공학
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• 제9권2호
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• pp.143-158
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• 1996

This paper deals with the development of a software module for production planning and scheduling activities of an actual die-production management system. Scheduling problems, such as master schedule and detailed schedule, are the focal point of the whole article and they are considered in terms of operation procedures. Schedule-explosion module and load levelling module are the essential components of schedule management. The scheduling module allocates the resources, determines the process priority and the planned start and completion dates of processes. Rescheduling can be done to manipulate unforeseen situations that schedule is delayed owing to inducing defectives, machine breakdowns and lumpy demands. This study indicates a practical model for the die-producation management and helps to apply it for jobs in the real situation.

• Journal of Computational Design and Engineering
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• 제3권2호
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• pp.132-139
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• 2016

In this paper, a minimum time path planning strategy is proposed for multi points manufacturing problems in drilling/spot welding tasks. By optimizing the travelling schedule of the set points and the detailed transfer path between points, the minimum time manufacturing task is realized under fully utilizing the dynamic performance of robotic manipulator. According to the start-stop movement in drilling/spot welding task, the path planning problem can be converted into a traveling salesman problem (TSP) and a series of point to point minimum time transfer path planning problems. Cubic Hermite interpolation polynomial is used to parameterize the transfer path and then the path parameters are optimized to obtain minimum point to point transfer time. A new TSP with minimum time index is constructed by using point-point transfer time as the TSP parameter. The classical genetic algorithm (GA) is applied to obtain the optimal travelling schedule. Several minimum time drilling tasks of a 3-DOF robotic manipulator are used as examples to demonstrate the effectiveness of the proposed approach.

• 한국항해항만학회지
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• 제32권4호
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• pp.295-304
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• 2008

In order to achieve a sustainable competitive advantage in the expanding maritime transportation market, most shipping companies are making every effort to reduce transportation costs. Likewise, the car shipping companies, which carry more than 80% of total car import and export logistics volume, also do their utmost for transportation cost saving. Until now many researches have been made for efficient maritime transportation, but studies for car shipping companies have rarely been made. For this reason, this study has tried to develop a maritime transportation planning support system which can help to save logistics costs and increase a competitive power of car shipping companies. To this end, instead of manual effort to solve the routing problem of car carrier vessels, this study has used an integer programming model to make an optimal transportation planning at the minimum cost. Also in response to the frequent changes both in the car production schedule and ship's arrival schedule after the completion of transportation planning, this research has developed a decision support system of maritime transportation, so that users can easily modify their existing plans.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.597-600
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• 2008

최근 국내에서 도심재생을 위한 입체복합공간 개발사업으로 여러 메가프로젝트가 수행중이지만, 메가프로젝트 실적 자료 및 경험, 기술부족으로 인해 여러 가지 문제점들이 드러나고 있다. 다양한 유형의 프로젝트들로 구성된 입체 복합공간 개발 사업에서 프로그램 및 프로젝트 수준으로 메가프로젝트를 관리할 수 있는 기술이 요구된다. 메가프로젝트는 다년간에 걸쳐 수행되는 사업으로 사업기간 예측과 그에 따른 공정관리가 무엇보다 중요하다. 따라서 메가프로젝트 특성에 맞는 프로그램레벨에서의 공정관리 기술 개발이 필요하다. 본 연구에서는 공정관리 기술개발의 선행연구로 사업초기단계 사업기간 예측 및 일정 계획 방법에 대해서 제시하였다. 먼저 과거 수행된 단일시설 및 복합시설의 프로젝트 속성정보와 설계 및 공사기간의 일정데이터를 수집하여, 프로젝트 기간 예측을 위한 DB의 개발방향을 제시하였다. 그리고 메가프로젝트 사업초기단계 사업기간 예측 시 영향을 미치는 발주자의 요구사항과 사업비 투입계획에 따라 시나리오를 개발하여 사업기간 예측 방법에 대해 제시하였고, CCPM을 통한 사업기간 단축가능성을 제시하였다.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5890-5896
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• 2013

본 연구는 BIM 기반의 납품체계에서 IFC 파일의 공정정보를 축적하고 활용하기 위한 방안을 제시하였다. 이를 위해 첫 번째로, 공정정보의 활용방안에 대하여 기존연구를 분석하였고, IFC 표준을 고찰하였다. 두 번째로, 공정요소를 도출하기 위해 공정계획 수립절차를 분석하였으며, 공정프로세스와 상용소프트웨어를 분석하여 공정정보항목을 도출하였다. 또한 도출된 공정정보항목을 기반으로 IFC 스키마를 분석하여 IFC의 공정요소를 도출하였다. 마지막으로 IFC 납품파일의 축적을 위해 조달청의 시설사업 BIM 적용 기본 지침서를 분석하여 개념적인 BIM 모델의 납품프로세스를 통한 축적방법과 활용방안을 제시하였다. 본 연구는 국가적으로 진행되고 있는 BIM 도입과정에서 BIM모델의 정보를 축적하는데 기여할 것으로 기대된다.