• Industrial Engineering and Management Systems
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• 제12권4호
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• pp.330-335
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• 2013

A surface mount device (SMD) assembles electronic components on printed circuit boards (PCB). Since a component assembly process is a bottleneck process in a PCB assembly line, making an efficient SMD plan is critical in increasing the PCB assembly line productivity. Feeder assignment is an important part of the SMD plan optimization. In this paper, we propose a feeder re-assign improvement algorithm for a specific type of SMD machine with a piano type multi-head gantry. Computational results on some real-world benchmark data sets show the effectiveness of our proposed algorithm.

• Journal of Ship and Ocean Technology
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• 제2권1호
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• pp.42-57
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• 1998

Genetic Algorithm (GA) is applied to obtain optimal Inspection plan for fatigue deteriorating structures. The optimization problem is defined so as to minimize inspection cost in the 1ifs-time of the structure under the constraint that the increment of failure probability in each inspection interval is maintained below a target value. Optimization parameters are the inspection timing and the inspection quality. The inspection timing is selected from the discrete intervals such as one year, two years, three years, etc. The inspection quality is selected from the followings; no inspection, normal inspection, sampling inspection or precise inspection. The applicability of the proposed GA approach is demonstrated through the numerical calculations assuming a structure consisting of four member sets. Influences of the level of target failure probability, initial defect condition and stress increase due to plate thickness reduction caused by corrosion on inspection planning are discussed.

• Industrial Engineering and Management Systems
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• 제11권1호
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• pp.39-47
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• 2012

Requirements definition, which determines a project baseline, has a strong impact on the success of a project. However, since in-depth requirements are gradually revealed through the requirements definition process, the requirements definition is not a straight forward process and often falls into disorder. Thus project management standpoints are critical for the success of the requirements definition. In this paper, we present a framework and mechanisms of communication-centered project management, which controls the requirements definition process based on the situation of communication-oriented activities among stakeholders. In addition, we present a communication-centered project plan with a planning method. The project plan, which represents a time schedule of requirements definition activities, is made by a simulation-optimization algorithm using a stakeholder matrix showing the relations of requirements domains and relevant stakeholders. The effectiveness and the significance of communication-centered project management at the requirements definition phase are demonstrated by numerical examples.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1047-1052
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• 2009

As buildings nowadays become taller in height and larger in size the safety review of lifting plan takes larger portion in construction project management. However, the cost and safety in lifting plan have a contradictory effect on each other. Therefore, an optimization algorithm needs devising as a solution of the contradictory problem. In many cases at construction sites, selections and stability review of tower cranes are assigned to equipment suppliers or field managers, which cause the problems in safety and cost of the projects. To improve the part of the current situation, a study on the optimization algorithm for designing the foundation of tower cranes is conducted in this study, which can be utilized by equipment suppliers or field managers to check the stability of tower cranes easily and promptly without substantial knowledge.

• 한국인터넷방송통신학회논문지
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• 제14권4호
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• pp.107-112
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• 2014

본 연구에서는 다중 사용자 환경의 볼륨 가시화(Volume Rendering)에서 변환 함수(Transfer Function)의 최적화 방안을 연구한다. 볼륨 데이터에 따라 필요한 변환 함수의 형태가 다르기 때문에 여러 번의 시행착오를 겪어야 필요한 변환 함수를 얻을 수 있는데, 이를 방지하기 위해 크라우드 소싱 기법을 이용하여 변환 함수의 파라미터를 최적화 하는 방안을 제안한다. 다중 사용자 환경에서 각 사용자마다 신뢰도에 따른 레벨을 지정하여 가중치로 사용한다. 이전 사용자가 사용했던 변환 함수 파라미터는 가중치만큼 다음 사용자에게 제공되기 때문에 다음 사용자는 변환 함수의 최적 파라미터를 찾기 위한 시도횟수를 줄일 수 있다.

• 한국해양공학회지
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• 제18권4호
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• pp.65-70
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• 2004

Many port states, such as New Zealand, U.S.A., Australia, and Canada, have strict regulations to prevent arriving ships from discharging polluted ballast water that contains harmful aquatic organisms and pathogens. They are notified that transfer of polluted ballast water can cause serious injury to public health and damage to property and environment. For this reason, ballast exchange in deep sea is perceived as the most effective method of emptying ballast water. The ballast management plan contains the effective exchange method, ballast system, and safety considerations. In this study, we pursued both nautical engineering analysis and optimization of the algorithm, in order to generate the sequence of stability and rapidity. A heuristic algorithm was chosen on the basis of optimality and applicability to a sequential exchange problem. We have built an optimized algorithm for the automatic exchange of ballast water, by redefining core elements of the A$\ast$ algorithm, such as node, operator, and evaluation function. The final version of the optimized algorithm has been applied to existing bulk carrier, and the performance of the algorithm has been successfully verified.

• 한국건설관리학회논문집
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• 제25권3호
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• pp.68-82
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• 2024

The planning stage of laser scanning is crucial for acquiring high-quality 3D source data. It involves assessing the target space's environment and formulating an effective measurement strategy. However, existing practices often overlook on-site conditions, with decisions on scanner deployment and scanning locations relying heavily on the operators' experience. This approach has resulted in frequent modifications to scanning locations and diminished 3D data quality. Previous research has explored the selection of optimal scanner locations and conducted preliminary reviews through simulation, but these methods have significant drawbacks. They fail to consider scanner inaccuracies, do not support the use of multiple scanners, rely on less accurate 2D drawings, and require specialized knowledge in 3D modeling and programming. This study introduces an optimization technique for laser scanning planning using 3D simulation to address these issues. By evaluating the accuracy of scan data from various laser scanners and their positioning for scanning a retaining wall structure in a small-scale building, this method aids in refining the laser scanning plan. It enhances the decision-making process for end-users by ensuring data quality and reducing the need for plan adjustments during the planning phase.

• 교통기술과정책
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• 제12권6호
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• pp.16-24
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• 2015

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.941-942
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• 2005

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1414-1420
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• 2022

High dose rate (HDR) brachytherapy treatment planning usually involves optimization methods to deliver uniform dose to the target volume and minimize dose to the healthy tissues. Four optimizations were used to evaluate the high-risk clinical target volume (HRCTV) coverage and organ at risk (OAR). Dose-volume histogram (DVH) and dosimetric parameters were analyzed and evaluated. Better coverage was achieved with PGO (mean CI = 0.95), but there were no significant mean CI differences than GrO (p = 0.03322). Mean EQD₂ doses to HRCTV (D₉₀) were also superior for PGO with no significant mean EQD₂ doses than GrO (p = 0.9410). The mean EQD₂ doses to bladder, rectum, and sigmoid were significantly higher for NO plan than PO, GrO, and PGO. PO significantly reduced the mean EQD₂ doses to bladder, rectum, and sigmoid but compromising the conformity index to HRCTV. PGO was superior in conformity index (CI) and mean EQD₂ doses to HRCTV compared with the GrO plan but not statistically significant. The mean EQD₂ doses to the rectum by PGO plan slightly exceeded the limit from ABS recommendation (mean EQD₂ dose = 78.08 Gy EQD₂). However, PGO can shorten the treatment planning process without compromising the CI and keeping the OARs dose below the tolerance limit.