• 대한안전경영과학회지
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• 제4권3호
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• pp.95-105
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• 2002

This paper considers the sequencing of products in car assembly lines under Just-In-Time systems. Under Just-In-Time systems, the most important goal for the sequencing problem is to keep a constant rate of usage every part used by the systems. In this paper, tabu search technique for this problem is proposed. Tabu search is a heuristic method which can provide a near optimal solution in real time. The performance of proposed technique is compared with existing heuristic methods in terms of solution quality and computation time. Various examples are presented and experimental results are reported to demonstrate the efficiency of the technique.

• 산업공학
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• 제20권2호
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• pp.112-120
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• 2007

As the market rapidly changes, the speed of new product development is highlighted as a critical element which determines the success of firms. While firms endeavor to accelerate the development speed, frequent iterations in a development process hinders the effort of acceleration. For this reason, many previous researches tried to find the optimal structure of the development process which minimizes the number of iterations. However, such researches have a limitation in that they can be applied to only a single-project environment. In a multi-project environment, waiting time induced by lack of resources also delays the process as well as the iterations do. In this paper, we propose dynamic sequencing method focusing on both iterations and waiting time for reducing the durations of development projects in a multi-project environment. This method reduces the waiting time by changing the sequence of development tasks according to the states of resources. While the method incurs additional iterations, they are expected to be offset by the reduced waiting time. The results of simulation show that the dynamic sequencing method dramatically improves the efficiency of a development process. Especially, the improvement is more salient as projects are more crowded and the process is more unbalanced. This method gives a new insight in researches on managing multiple development projects.

• 농업과학연구
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• 제44권4호
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• pp.495-503
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• 2017

Genotyping-by-sequencing (GBS) is an outstanding technology for genotyping and single nucleotide polymorphism (SNP) discovery compared to next generation sequencing (NGS) because it can save time when analyzing large-scale samples and carries a low cost per sample. Recently, studies using GBS have been conducted on major crops and, to a greater extent, on fruit crops. However, many researchers have some problems due to low GBS efficiency resulting from low quality GBS libraries. To overcome this limitation, we developed an efficient GBS library construction method that regulates important conditions such as restriction enzymes (RE) digestion and a PCR procedure for grapevine. For RE digestion, DNA samples are digested with ApeKI (3.6U) at $75^{\circ}C$ for 5 hours and adapters are ligated to the ends of gDNA products. To produce suitable PCR fragments for sequencing, we modified the PCR amplification conditions; temperature cycling consisted of $72^{\circ}C$ (5 min), $98^{\circ}C$ (30 s), followed by 16 cycles of $98^{\circ}C$ (30 s), $65^{\circ}C$ (30 s), $72^{\circ}C$ (20 s) with a final extension step. As a result, we had obtained optimal library construct sizes (200 to 400 bp) for GBS analysis. Furthermore, it not only increased the mapping efficiency by approximately 10.17% compared to the previous method, but also produced mapped reads which were distributed equally on the19 chromosomes in the grape genome. Therefore, we suggest that this system can be used for various fruit crops and is expected to increase the efficiency of various genomic analysis performed.

• 대한산업공학회지
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• 제20권3호
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• pp.79-92
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• 1994

Surface mount technology has been evolving in the electronics industries. Efficient operation of surface mounters is closely related with the productivity of the electronic products. In this study, modeling and optimal algorithm for allocating feeders and sequencing mounting jobs in the rotary type surface mounter, which consider all the constraints, in the hardware and are easy to be used in the field, are developed.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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• pp.305-308
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• 2007

In this paper we suggest an efficient evolutionary approach based on topological sort techniques for precedence constrained TSPs. The determination of optimal sequence has much to offer to downstream project management and opens up new opportunities for supply chains and logistics. Experimental results show that the suggested approach is a good alternative to locate optimal solution for complicated precedence constrained sequencing as in optimization method for instance.

• 지능정보연구
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• 제17권2호
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• pp.1-22
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• 2011

본 논문에서는 선행제약순서결정문제(Sequencing problem with precedence constraints, SPPC)를 효과적으로 해결하기 위한 적응형 유전알고리즘(Adaptive genetic algorithm, aGA)을 제안한다. aGA에서 는 SPPC를 효과적으로 표현하기 위해 위상정렬에 기초한 표현절차(topological sort-based representation procedure) 를 사용한다. 제안된 aGA는 퍼지로직제어를 이용한 적응형구조를 가지고 있으며, 유전 탐색과정을 통해 교차변이 연산자(Crossover operator)의 비율을 적응적으로 조절한다. 수치예제에서는 다양한 형태의 SPPC를 제시하였으며, 그 실험결과는 제안된 aGA가 기존의 알고리즘보다 우수함을 보여주었다. 결론적으로 말하자면 본 논문에서는 제안된 aGA가 다양한 형태의 SPPC에서 최적해 혹은 최적순서를 발견하는데 아주 효과적이라는 것을 밝혔다.

• 한국환경과학회지
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• 제31권4호
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• pp.295-309
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• 2022

The purpose of this study was to evaluate the operational characteristics of wastewater treatment using Sequencing Batch Reactor (SBR) with Aerobic Granular Sludge (AGS) separator in the pilot plant. Pilot plant experiments were conducted using SBR with AGS separator and pollution removal efficiencies were evaluated based on the operational condition and surface properties of AGS. The results of the operation on water quality of the effluent showed that the average concentration of total organic carbon, suspended solids, nitrogen, and phosphorus was 6.89 mg/L, 7.33 mg/L, 7.33 mg/L, and 0.2 mg/L, respectively. All these concentrations complied the effluent standard in Korea. The concentration of mixed liquor suspended solid (MLSS) fluctuated, but the AGS/MLSS ratio was constant at 86.5±1.3%. Although the AGS/MLSS ratio was constant, sludge volume index improved. These results suggested that the particle discharged fine sludge and increased the AGS praticle size in the AGS. Optical microscopy revealed the presence of dense AGS at the end of the operation, and particles of > 0.6 mm were found. Compared to those of belt-type AGS separator, the required area and power consumption of the hydrocyclone-type AGS separator were reduced by 27.5% and 83.8%, respectively.

• 농업생명과학연구
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• 제43권2호
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• pp.31-38
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• 2009

DNA sequencer는 template로 이용하는 DNA의 quality와 sequencing 반응 산물의 정제 방법, 그리고 gel 농도에 민감하다고 알려져 있다. 이에 우리는 plasmid DNA의 준비, 정제, sequencing 반응, gel 농도와 injection medium 등에 대한 최적 조건을 구축하기 위한 연구를 수행하였다. Plasmid DNA 준비과정에서 phenol을 사용한 것 보다 chloroform을 사용한 것이 평균 reading length가 532 bp에서 684 bp로 향상되었으며, 2.5% DMSO를 첨가한 것이 첨가하지 않은것에 비해 200 bp 더 길게 염기서열 분석이 되었다. 또한, sequencing 반응산물 정제 시 50 mM EDTA와 0.6 M sodium acetate를 미리 섞어서 pH 8.0으로 맞춘 것을 사용한 것이 50 mM EDTA(pH 8.0)와 0.6 M sodium acetate(pH 5.2)를 각각 사용한 것 보다 20 bp 길게 염기서열 분석이 되었다. Injection medium으로는 실험실에서 resin으로 탈 이온화 시킨 formamide보다 정제된 ABI formamide를 사용한 것이 보다 재현성 있게 reading length가 90 bp 더 길게 분석 되었으며, 4% PAGE gel 보다 3.6% PAGE gel을 사용한 것이 150 bp 더 길게 분석 되었다. Template 준비 시 chloroform으로 정제하고 2.5% DMSO를 첨가, sequencing 반응산물 정제 시 carrier의 pH를 8.0으로 맞춘 것을 이용, 그리고 ABI formamide와 3.6% gel 농도를 사용하는 최적의 조건으로 평균 700 bp, 85% score를 얻을 수 있었다.

• 한국경영과학회지
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• 제13권1호
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• pp.13-13
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• 1988

This paper considers the sequencing problem in mixed model assembly lines with hybrid workstation types and sequence-dependent setup times. Computation time is often a critical factor in choosing a method of determining the sequence. We develop a mathematical formulation of the problem to minimize the overall length of a line, and present a tabu search technique which can provide a near optimal solution in real time. The proposed technique is compared with a genetic algorithm and a branch-and-bound method. Experimental results are reported to demonstrate the efficiency of the technique.

• 대한산업공학회지
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• 제5권1호
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• pp.67-82
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• 1979

For many capacity expansion problems, distinct capacity types must be specified to identify capacity at different locations or capacities with different costs and operating characteristics. In this study, a project-sequencing model is developed that allows operating costs to influence the timing decisions for project establishment. Under certain conditions, the power expansion formulation is derived that may be solved through the dynamic programming approach, and its first application to planning in electric power systems is selected to investigate an optimal policy and to show the impact of requiring system to service more than one type of demand. Several sample testing results indicate that in some systems the efficiency of the large nuclear plants is higher than that of smell ones that it may overcome the effects of the drop in reliability.