This paper deals with the production plan for the foaming process, the core part of the refrigerator manufacturing process. In accordance with this change, the refrigerator manufacturing process has also been converted into the mixed-model production system and it is necessary to optimize the production release pattern for the foaming process. The pattern optimization is to create a mixed-model combination which can minimize the number of setup operations and maintain mixed-model production. The existing method is a simple heuristic that depends on the demand priority. Its disadvantages are low mixed-model configuration rate and high setup frequency. Therefore, demand partitioning occurs frequently. In this study, we introduce the tolerance concept and propose a new pattern optimization algorithm based the large neighborhood search (LNS). The proposed algorithm was applied to a refrigerator plant and it was found that mixed-model configuration rate can be improved without demand partitioning.

본 연구는 식물공장에서 특용작물인 인삼을 대상으로 LED광원, Duty비와 Hertz에 따른 최적 환경조건을 알아보 고자 하였다. LED광원의 종류는 적색+청색 혼합광(R+B), 적색+청색+백색 혼합광(R+B+W)을 이용하였으며, R+B광 원의 Hz는 각각 20, 60, 180, 540, 1620, 4860Hz로 R+B+W 광원의 Hz는 각각 60, 180, 540, 1620Hz로 처리하여 총 10개의 구배를 하였다. 인삼은 1년생 묘삼을 한 화분(지름 24cm×높이23cm)에 3개체씩 이식하여 각 처리구당 5개의 화분을 배치하였다. 그리고 이 실험을 각각 Duty비 30%, 50%, 70%로 총 3번 진행하였다. 실험 결과, 광합성률은 R+B광원에서 Duty비 30%일 때 180Hz가 가장 높았고, Duty비 50%일 때는 20Hz가 가장 높았다. R+B+W광원에 서는 Duty비 50%일 때 60Hz가 가장 높았고, Duty비 70% 일 때는 180Hz가 가장 높았다. 증산률은 R+B광원에서 Duty비 30%일 때 60Hz가 가장 높았고, Duty비 50%일 때 는 20Hz와 1620Hz가 가장 높았다. R+B+W광원에서는 Duty비 30% 일 때 60Hz가 가장 높았고, Duty비 50%일 때는 180Hz와 540Hz 그리고 Duty비 70%일 때는 540Hz가 가장 높았다. 기공전도도는 R+B광원에서 Duty비 30%일 때 60Hz가 가장 높았고, Duty비 50%일 때 20Hz가 가장 높았다. R+B+W광원에서는 Duty비 30%일 때 60Hz가 가 장 높았다. 특히 광합성률에서는 R+B+W광원에서 Duty비 30%일 때 Hertz간의 유의적인 차이는 나타나지 않았지만, R+B와 R+B+W광원 모두 Duty비 30%에서 가장 높은 광합 성률을 보였다. 또한 R+B+W광원에서 보다 R+B광원에서 Duty비 30%일 때 더 높은 광합성률을 보였다. 위의 결과를 종합해보았을 때 R+B와 R+B+W광원 모두 60Hz와 180Hz 에서 가장 최적의 생리·생태학적 반응이 나타났으며, R+B 광원에서 Duty비 30%일 때 인삼의 최적 환경 조건을 유지 하며 에너지 절감 또한 될 것으로 판단된다.

PURPOSES : The purpose of this study is to present a linear programing optimization model for the design of lane-based lane-uses and signal timings for an isolated intersection. METHODS: For the optimization model, a set of constraints for lane-uses and signal settings are identified to ensure feasibility and safety of traffic flow. Three types of objective functions are introduced for optimizing lane-uses and signal operation, including 1) flow ratio minimization of a dual-ring signal control system, 2) cycle length minimization, and 3) capacity maximization. RESULTS : The three types of model were evaluated in terms of minimizing delay time. From the experimental results, the flow ratio minimization model proved to be more effective in reducing delay time than cycle length minimization and capacity maximization models and provided reasonable cycle lengths located between those of other two models. CONCLUSIONS : It was concluded that the flow ratio minimization objective function is the proper one to implement for lane-uses and signal settings optimization to reduce delay time for signalized intersections.

PURPOSES : This study was conducted to derive the optimum mixing ratio of phosphorescent pigment for the development of phosphorescent line marking. METHODS: In this study, we utilized a literature review and case study methodology, to describe the domestic and foreign state of practice for the production and mixing of phosphorescent pigment for use in line marking. The optimal mixing ratio was derived by comparing the reduction in luminance over time for the various phosphorescent pigment mixing ratios identified in the literature. In addition, performance and construction characteristics were analyzed using field testing techniques. RESULTS : The results were as follows: 1) the results of the luminance performance standards tests showed that all of the phosphorescence test specimens satisfied the phosphorescent fire protection standard. As the phosphorescent pigment mixing ratio increased, the luminance value increased, 2) the luminance reduction rate was minimum at the mixing ratio of 50%. However, when compared to a mixing ratio 40%, a small difference was recorded, the luminance reduction rate from the mixing ratio of 40% is judged as being converged. Therefore, in view of the economic efficiency, it was determined that the optimal mixing ratio was 40%, 3) as a result of construction on the field, a mixing ratio of 40% was found to have a higher luminance value than the general line marking for up to three hours after sunset, 4) it was found that the phosphorescent line markings without glass beads spraying had a higher luminance value than the phosphorescent line markings with glass beads spraying. CONCLUSIONS : Through the results of the basic experiments of the line markings obtained by blending a phosphorescent pigment, the results could be applied to play an important role in the development of phosphorescent line marking paint technology and in establishing application planning for on-site construction characteristics.

과거 짧은 시간 내에 급격한 도로 인프라의 건설로 대다수 포장도로의 노령화 정도가 유사하고, 이에 따라 대규모 도로시설물 유지보수 사업을 위한 물량이 도출될 것으로 예상한다. 이에 대한 서울시의 예산 및 시간 제한문제를 고려할 때, 최적의 포장도로 유지 ․ 보수 전략 수립이 필요하다. 또한, 서울시 도로시 설물 공사는 주로 야간에 시행되며 도로포장면의 강성확보를 위한 타설 후 포장면 온도저하를 위한 충분 한 시간부족으로 조기파손 및 영구변형량 증가의 문제를 야기하고 있어, 도로 재포장 주기의 급격한 감소 의 원인이 되고 있다. 교통량이 많은 주간에 보수공사를 시행할 경우 도로용량을 감소시켜 교통혼잡으로 인한 사회적 비용이 발생될 우려가 있다. 국외에서는 여러 공사시간대의 교통지체, 교통량, 차량통제방안, 공사비용, 운전자지체비용을 고려한 사회적비용을 공사 전에 산출하여 비용이 최소화되는 최적의 공사시간대를 도출하는 것으로 나타났다. 하 지만, 검토한 국외 방법론은 야간공사의 제한된 공사시간으로 인한 짧은 양생 시간을 간과하였다. 따라서 본 연구는 서울시의 교통혼잡 최소화 및 양생시간 확보로 공사의 품질 보장이 반영된 사회적비용을 최소 화 할 수 있는 최적의 공사시간대를 수립하는데 목적이 있다. 본 연구에서는 야간공사로 인해 늘어나는 서울시의 재공사비용을 줄이기 위한 방안으로 야간공사의 주 간시간대 확대에 따른 비용편익 비교분석을 시행하였다. 비용편익 비교분석은 야간공사와 주간공사의 비 용분석과 편익분석으로 이루어진다. 본 연구의 비용분석으로 도로공사 자체의 사업비와 함께 야간공사와 주간공사의 지체 비용을 비교분석할 것이다. 또한 편익분석으로 도로포장 갱생시간과 수명간의 관계식을 산출하여 충분한 도로포장체의 갱생시간 확보에 따른 포장체 수명연장으로 발생하는 공사비 절감편익과 사회비용 절감편익을 계산할 것이다. 잦은 재포장에 따른 교통지체에 의한 사회비용 및 사업비 등을 고려할 때, 충분한 포장면의 온도저하시 간확보를 위한 주간시간대로의 도로공사 시간 확대는 결과적으로 6배 이상의 사회비용 절감 및 서울시의 예산절감의 효과를 가능하게 할 것으로 보인다. 도로포장면의 수명을 확보하기 위해 도로포장면 다짐 후 충분한 온도저하시간동안 차량통행을 통제하여도 실제적인 지체에 의한 사회비용은 공사비에 비해 낮은 수준이다.

The effects of coating parameters were investigated in wear resistance coatings of Diamalloy-406 on Inconel 718 to obtain an optimum coating condition by high velocity oxy-fuel spraying. The coating parameters, the flow rates of source gases (hydrogen and oxygen), the powder feed rate, and the spray distance, were designed by the Taguchi method. The optimal conditions were determined: oxygen flow rate 34 FRM, hydrogen flow rate 57 FRM, powder feed rate 35 g/min, and spray distance 7 inch. Friction coefficients of the coating and the substrate decreased with an increasing sliding surface temperature from 25 oC to 450 oC. The friction coefficient of Diamalloy-4006 coating decreased as the sliding surface temperature increased from 0.43 ± 0.01 at 25 oC to 0.29 ± 0.01 at 450 oC. The wear trace and wear depth of the coating were smaller than the substrate at all temperatures tested. The relationship between spray parameters and wear resistance was discussed extensively, based on the measured roughness, hardness, and porosity in each coating.

최근 고기능성 제품에 대한 수요가 증가함에 따라 ICT 기능과의 융합을 통한 스마트 의류는 일상생활 분야로 확대되고 있다. 그 중 하나로, 발열 텍스타일 및 제어 모듈을 통해 의복 내 발열기능을 조절하는 스마트 의류에 대한 관심이 높아지고 있으며, 발열 기능을 갖는 스마트 의류의 시장 전망이 높아지고 있으나, 발열 패드 부착위 치에 따른 발열 기능의 효용성 및 온열감에 대한 연구는 부족한 실정이다. 본 연구에서는 발열 패드의 위치에 따 른 피부온의 변화와 온열감에 대한 실증적 연구를 통하여 발열기능의 스마트 의류 개발을 위한 최적의 발열 위 치를 도출하고자 하였다. 이를 위하여 20대 표준체형의 남성 10명을 피험자로 선정하였으며, 영하 5 ℃의 인공기후실에서 20분의 안정기, 20분의 처치기, 40분의 회복기를 통해 11군데에서의 피부온, 직장온과 주관적 온열감을 측정, 평가하였다. 최종적으로, 발열패드를 위한 최적의 위치를 도출하고 제시하였다.

In this study, granting the optimal loan limit on SME (Small and Medium Enterprise) loans of financial institutions was proposed using the traditional newsvendor model. This study was the first domestic case study that applied the newsvendor model that was mainly used to calculate the optimum order quantity under some uncertain demands to the calculation of the loan limit (debt ceiling) of institutions. The method presented in this study made it possible to calculate the loan limit (debt ceiling) to maximize the revenue of a financial institution using probability functions, applied the newsvendor model setting the order volume of merchandise goods as the loan product order volume of the financial institution, and proposed, through the analysis of empirical data, the availability of additional loan to the borrower and the reduction of the debt ceiling and a management method for the recovery of the borrower who could not generate profit. In addition, the profit based loan money management model presented in this study also demonstrated that it also contributed to some extent to the prediction of the bankruptcy of the borrowing SME (Small and Medium Enterprise), as well as the calculation of the loan limit based on profit, by deriving the result values that the borrowing SME (Small and Medium Enterprise) actually went through bankruptcy at later times once the model had generated a signal of loan recovery for them during the validation of empirical data. accordingly, The method presented in this study suggested a methodology to generated a signal of loan recovery to reduce the losses by the bankruptcy.

Recently, the Ministry of Labour, published clause 2 of Article 41 (Risk Assessment) of the Act "Industrial Safety and Health" dated 12 June 2013 in connection with continuous increase of accidents at construction sites in order to prevent accidents in industrial safety and health in new construction in accordance with the risk assessment on construction projects are realized after March 13, 2014. In this paper, positive method of calculating risk discussed by performing research the awareness of general contractors and sub-contractors with presenting risky situation is considered. The purpose will be a positive method of calculating risk and would be a sufficient basе and give a positive direction in the development of new systems currently working in the construction and risk assessment which consider the characteristics of sufficient risk assessment system for future research.

The risk assessment carried out on the construction site at the beginning of the implementation depends on the subjective judgment of risk of general contractor and subcontractors, whose opinion about frequency and intensity of risk is different. In this paper, research the awareness of general contractors and subcontractors about process of risk assessment at the construction site and its effectiveness. Researching of the main factors "frequency", "intensity" which determines the degree of risk gives the opportunity to find an option for improving the effective implementation of risk assessment.

본 논문에서는 균열 진전문제에 대하여 페리다이나믹스 이론을 이용하여 설계민감도 해석 및 구조 최적설계를 수행하였다. 페리다이나믹스는 해의 불연속성을 다루기 어려웠던 기존의 연속체 이론에 비해 균열 진전문제와 같은 불연속성을 가지는 문제를 자연스럽게 표현할 수 있다는 장점을 가지고 있다. 최적설계를 진행하기 위하여 애조인 변수법으로 설계민감도를 유도하였다. 특히 균열이 진전되더라도 애조인 변수법으로 계산된 변위장과 변형에너지에 대한 설계민감도 값은 유한차분법과 비교하여 매우 정확하고 효율적임을 보였다. 이를 바탕으로 간단한 인장응력 하의 균열진전 문제에 대하여 균열의 분기가 발생하는 위치를 조절하기 위하여 정해진 시간구간에서 변형에너지 값을 줄이는 방향으로 최적설계를 수행하였다. 최적의 재료분포로 해석을 수행한 결과 균열의 분기점을 늦출수 있음을 확인하였다.

한국산 억새를 산, 알칼리 및 증기폭쇄법으로 전처리한 시료의 최적 효소당화조건을 탐색하고, 당화물을 이용한 에탄올 생산성을 구명하였다. 억새의 화학적 조성은 저분자화합물이 5.0%, lignin 17.0%, hemicellulose 55.1%, cellulose 22.7%이었다. 효소 당화율은 단용효소 처리구보다 혼용효소 처리구에서 높았다. Celluclast 처리구는 Viscozyme보다 높은 당화율을 보였으며, 가장 높은 당화율을 보인 효소 처리구는 EM-3(Celluclast 24.3FPU/g 기질+Viscozyme 80.6FBG/g 기질)로 약 70%의 당화율을 보였다. 산,알칼리 전처리를 통해 정제된 α-cellulose의 효소 당화율은 1% NaOH 처리 증기폭쇄재 보다 16% 높게 나타났다. 효소 cocktail의 당화에 가장 적합한 온도는 50℃였고, 모든 기질에서 효소 반응시간이 증가할수록 당화율이 증가하였다. 억새의 당화물은 오탄당으로 xylose가 육탄당으로 glucose가 주를 이루었다. S. cerevisiae KCCM 11215를 이용한 당화물의 에탄올 발효에서도 각 효소조합과 시료 전처리가 매우 중요한 것으로 나타났다. 억새시료 1kg 당 350g 이상의 에탄올 생산성을 보였으며, 1% NaOH 및 1% KOH를 처리한 증기폭쇄 시료보다 α-cellulose를 기질로 사용한 처리구에서 에탄올 생산성이 높았다.

This study aims to estimate optimal harvesting production, fishing efforts, and stock levels of yellow croaker caught by the offshore Stow Net and the offshore Gill Net fisheries using the current value Hamiltonian method and the surplus production model. As analyzing processes, firstly, this study uses the Gavaris general linear model to estimate standardized fishing efforts of yellow croaker caught by the above multiple fisheries. Secondly, this study applies the Clarke·Yoshimoto·Pooley(CY&P) model among the various exponential growth models to estimate intrinsic growth rate(r), environmental carrying capacity(K), and catchability coefficient(q) of yellow croaker which inhabits in offshore area of Korea. Thirdly, the study determines optimal harvesting production, fishing efforts, and stock levels of yellow croaker using the current value Hamiltonian method which is including average landing price of yellow croaker, average unit cost of fishing efforts, and social discount rate based on standard of the Korean Development Institute. Finally, this study tries sensitivity analysis to understand changes in optimal harvesting production, fishing efforts, and stock levels of yellow croaker caused by changes in economic and biological parameters. As results drawn by the current value Hamiltonian model, the optimal harvesting production, fishing efforts, and stock levels of yellow croaker caught by the multiple fisheries were estimated as 19,173 ton, 101,644 horse power, and 146,144 ton respectively. In addition, as results of sensitivity analysis, firstly, if the social discount rate and the average landing price of yellow croaker continuously increase, the optimal harvesting production of yellow croaker increases at decreasing rate and then finally slightly decreases due to decreases in stock levels of yellow croaker. Secondly, if the average unit cost of fishing efforts continuously increases, the optimal fishing efforts of the multiple fisheries decreases, but the optimal stock level of yellow croaker increases. The optimal harvest starts climbing and then continuously decreases due to increases in the average unit cost. Thirdly, when the intrinsic growth rate of yellow croaker increases, the optimal harvest, fishing efforts, and stock level all continuously increase. In conclusion, this study suggests that the optimal harvesting production and fishing efforts were much less than actual harvesting production(35,279 ton) and estimated standardized fishing efforts(175,512 horse power) in 2013. This result implies that yellow croaker has been overfished due to excessive fishing efforts. Efficient management and conservative policy on stock of yellow croaker need to be urgently implemented.

This paper is concerned with the optimal design of hyperbaric oxygen therapy system chamber with separated rooms for multi-users using stress analysis. Hyperbaric oxygen therapy is very important medical remedy for increasing the concentration of melted oxygen in human and animal body to recover the impaired cell for the healthy condition. This research proposed the proper procedures to design the physical specifications and investigate the mechanical design safety of hyperbaric oxygen chamber with two separated rooms using computational stress analysis with Solidworks program. The result of this research will be used to make the real size model of practical hyperbaric oxygen therapy system for multi-users with separated chamber.

Zermelo's navigation problem is that the ship reaches a particular target point in the minimum-time when it travels with a constant speed in a region of strong currents and its heading angle is the control variable. Its approximate solution for the minimum-time control may be found using the calculus of variation. However, the accuracy of its approximate solution is low since the solution is based on graph or table form from a complicated nonlinear equations. To improve the accuracy, we use a neural network. Through the computer simulation study we have found that the proposed method is superior to the conventional ones.

PURPOSES : A study on the efforts to minimize the road traffic noise has been underway. An attempt has been made to measure the noise level using a noise map; however, the attempt is limited to certain areas only. In general, a noise barrier is employed to prevent road traffic noise; however, unplanned noise barriers developed without considering the surrounding environment, including excessively high walls, cause problems such as infringement on prospect right. Noise ceiling at daytime in Korea is 68 dB(A), which is relatively higher than in other countries. METHODS: The noise barrier used mainly for road noise reduction was analyzed to estimate the optimal height. Related variables such as road width, the height of the upper part, distance to the building, and angle (for instance, 30。). RESULTS : A formula to calculate the optical height of the noise barrier, considering the road environment (i.e., parameters such as road width and distance to building), was developed in this study in an attempt to mitigate the noise generated from the road. CONCLUSIONS : The formula to calculate the noise barrier is expected to lead to cost saving, accurate installation of barriers, and protection of the right of prospect.

This research carried out an analysis on input cost and leakage reduction effect by leakage reduction method, focusing on the project for establishing an optimal water pipe network management system in the Taebaek region, which has been executed annually since 2009. Based on the result, optimal cost-benefit analysis models for water distribution network rehabilitation project were developed using DEA(data envelopment analysis) and multiple regression analysis, which have been widely utilized for efficiency analysis in public and other projects. DEA and multiple regression analysis were carried out by applying 4 analytical methods involving different ratios and costs. The result showed that the models involving the analytical methods 2 and 4 were of low significance (which therefore were excluded), and only the models involving the analytical methods 1 and 3 were suitable. From the result it was judged that the leakage management method to be executed with the highest priority for the improvement of revenue water ratio was installation of pressure reduction valve, followed by replacement of water distribution pipe, replacement of water supply pipe, and then leakage detection and repair; and that the execution of leakage management methods in this order would be most economical. In addition, replacement of water meter was also shown to be necessary in case there were a large number of defective water meters.

Optimal design of the water supply pipe network aims to minimize construction cost while satisfying the required hydraulic constraints such as the minimum and maximum pressures, and velocity. Since considering one single design factor (i.e., cost) is very vulnerable for including future conditions and cannot satisfy operator’s needs, various design factors should be considered. Hence, this study presents three kinds of design factors (i.e., minimizing construction cost, maximizing reliability, and surplus head) to perform multi-objective optimization design. Harmony Search (HS) Algorithm is used as an optimization technique. As well-known benchmark networks, Hanoi network and Gyeonggi-do P city real world network are used to verify the applicability of the proposed model. In addition, the proposed multi-objective model is also applied to a real water distribution networks and the optimization results were statistically analyzed. The results of the optimal design for the benchmark and real networks indicated much better performance compared to those of existing designs and the other approach (i.e., Genetic Algorithm) in terms of cost and reliability, cost, and surplus head. As a result, this study is expected to contribute for the efficient design of water distribution networks.