• 산업경영시스템학회지
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• 제36권2호
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• pp.17-24
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• 2013

This paper is to analyze the picking lead time for picking batch size in a warehouse system and to get minimum picking batch size that is the warehouse system feasible. The warehouse system consists of aisles and racks, which two racks face each other through aisle. The products are picked from the storage locations by batch size. The probability that items are picked in the each row of the rack in the aisle for order picking activity is derived. The picking lead time for picking batch size is the time passed from the first picking location to arrival at starting location in aisle picking all items included in a batch size. The picking lead time for picking batch size in an aisle is analyzed. The picking lead time for picking batch size in the whole warehouse system is obtained. The warehouse system is feasible if all items that customers order are picked from the storage locations for same period. The picking batch size that is the warehouse system feasible is obtained. The problem is analyzed, a solution procedure is developed, and a numerical example is shown to explain the problem.

• 한국환경보건학회지
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• 제26권2호
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• pp.70-79
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• 2000

This study was done for the purpose of investigating the status of the use and perceptions of pesticides among the farmers who spray them in person. And it was also done to provide the basic statistics for the Agricultural Health Policy and study. Over the part of agricultural area in Kyungju and Ulsan City, Korea, from July to September 1999, 1032 questionnaires were distributed and 561 of them were collected and 447 were analysed. Major results of this study are as follows. The proportion of those who have special location for pesticides storage was only 5.3%, and that of those who lock hte storage location was only 13.6%. As to the treatment of bottles after use, most common response was 'burn in home'(47.7%). Most farmers purchase pesticides through 'pesticide store' or 'Agricultural Cooperatives'. The knowledge and Usage of pesticides depends in large part on experiences. The farmers who cultivate orchard spray pesticides more frequently than those cultivate paddy rice mainly. Most common pesticides in use are oganophosphates and carbamates. And also the pesticides that contains so-called 'Environmental Hormone' are used. The perception about the hazards of pesticides is rather superficial and insufficient. 'Herbicide(Gramoxon·Paraco)'(38%) is accepted as the most hazardous by farmers.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4030-4048
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• 2022

In this study, road transportation tests were conducted with surrogate fuel assemblies under normal conditions of transport to evaluate the vibration and shock load characteristics of spent nuclear fuel (SNF). The overall test data analysis was conducted based on the measured acceleration and strain data obtained from the speed bump, lane-change, deceleration, obstacle avoidance, and circular tests. Furthermore, representative shock response spectrums and power spectral densities of each test mode were acquired. Amplification or attenuation characteristics were investigated according to the load transfer path. The load attenuated significantly as it transferred from the trailer to the cask. By contrast, the load amplified as it transferred from the cask to the surrogate SNF assembly. The fuel loading location on the cask disk assembly did not exhibit a significant influence on the strain measured from the fuel rods. The principal strain was in the vertical direction, and relatively large strain values were obtained in spans with large spacing between spacer grids. The influence of the lateral location of fuel rods was also investigated. The fuel rods located at the side exhibited relatively large strain values than those located at the center. Based on the strain data obtained from the test results, a hypothetical road transportation scenario was established. A fatigue evaluation of the SNF rod was performed based on this scenario. The evaluation results indicate that no fatigue damage occurred on the fuel rods.

• 한국디지털건축인테리어학회논문집
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• 제12권1호
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• pp.53-59
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• 2012

This research studied the characteristics of the customer circulation in four department store food court restaurants located in Seoul. The characteristics of the customer circulation are the following: Before customers leave the dining space where they eat food, they come and go to spaces such as the water purifier space, the napkin storage, and the cup storage. On the other hand, they do not come and go from the dining space to the waste area or the area where used cups are returned. Therefore the spaces, that need to be located very near the dining space, are the water purifier space, the cup storage, and the napkin storage. The waste area does not have to be placed very near the dining area and the area where used cups are returned is not needed. A minority of customers drink water and use napkins after going to the waste area and the area where dirty dishes are kept. To prevent these customers from going against the circulation of the majority of customers, a water purifier space, a cup storage, and a napkin storage should be placed additionally connecting to the waste area and the area where dirty dishes are kept. For effective circulation plan and spatial composition of food court restaurants, these characteristics of customer circulation should be considered. It is not recommended to place the water purifier space, the napkin storage, and the cup storage, the waste area or the area where used cups are returned, and the hand cleansing facility in the same location just for the convenience of workers.

• International Journal of Internet, Broadcasting and Communication
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• 제10권3호
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• pp.26-34
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• 2018

In this paper, we propose a scheduling scheme that can efficiently serve I/O requests having deadlines in flash storage. The I/O requests with deadlines, namely, real-time requests, are assumed to be issued for streaming services of continuous media. Since a Web-based streaming server commonly supports downloads of HTMLs or images, we also aim to quickly process non-real-time I/O requests, together with real-time ones. For this purpose, we adopt the well-known rate-reservation EDF (RR-EDF) algorithm for determining scheduling priorities among mixed I/O requests. In fact, for the use of an EDF-style algorithm, overhead of task's switching should be low and predictable, as with its application of CPU scheduling. In other words, the EDF algorithm is inherently unsuitable for scheduling I/O requests in HDD storage because of highly varying latency times of HDD. Unlike HDD, time for reading a block in flash storage is almost uniform with respect to its physical location. This is because flash storage has no mechanical component, differently from HDD. By capitalizing on this uniform block read time, we compute bandwidth utilization rates of real-time requests from streams. Then, the RR-EDF algorithm is applied for determining how much storage bandwidth can be assigned to non-real-time requests, while meeting deadlines of real-time requests. From this, we can improve the service times of non-real-time requests, which are issued for downloads of static files. Because the proposed scheme can expand flexibly the scheduling periods of streams, it can provide a full usage of slack times, thereby improving the overall throughput of flash storage significantly.

• 문화기술의 융합
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• 제9권6호
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• pp.319-327
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• 2023

이 연구의 목적은 고속도로 휴게소에 설치된 소형 LPG 저장탱크의 폭발에 따른 영향범위를 분석하는데 있다. 이를 위해 휴게소에 설치된 2,900 kg 소형 LPG 저장탱크의 증기운 폭발(VCE)과 비등액체팽창증기 폭발(BLEVE)로 인한 과압과 복사열의 영향범위를 ALOHA(Areal Location of Hazardous Atmospheres)프로그램을 적용하여 정량적으로 평가하였다. 도출된 폭발 과압과 복사열의 영향범위는 각각 최대 반경 336 m와 423 m로 나타났다. 269 m 이내의 사람들은 3.5 psi이상의 과압으로 중상을 입을 수 있고, 192 m 이내의 사람들은 10 kw/m²이상의 복사열로 사망할 수 있는 것으로 예측되었다. 나아가 고속도로 휴게소 부대시설과 피해 영향범위를 고려한 LPG 저장 탱크의 안전관리 방안에 대해 논의하였다. 이러한 연구 결과는 고속도로 휴게소에 설치된 소형 LPG 저장탱크의 안전관리뿐만 아니라 휴게소 환경 및 시설을 고려한 안전사고 예방 규정 개선에 도움을 줄 수 있을 것이다.

• 산업기술연구
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• 제22권A호
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• pp.127-135
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• 2002

In this study, the preliminary risk assessment for the underground storage tanks(UST) in Chunchon city was implemented using the geographical information system(GIS). The estimation variables, such as the installation year, storage capacity, the distances from streams, and from groundwater pumping wells, were selected to estimate the relative risk levels. The weighting factors were given to all the estimation variables. Cumulative scores were induced by the combination of all the scores of the corresponding variables using the buffering technique and the overlay analysis in ArcView. Using the these process, the relative risk level of each UST was estimated. Some sites in this study are simplified and reduced because the number of useable data are limited or too enormous. Thus the selection of the comprehensive estimation variables and the proper weighting values are required for the future study. The methodology in this study could be served not only for the preliminary risk assessment of UST but also for the selection of the proper location of new and old UST. And, it can be used for the effective management system of UST.

• 한국화재소방학회논문지
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• 제34권1호
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• pp.26-36
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• 2020

랙크식 창고 화재의 경우 랙크에 적재된 가연성물품사이의 송기공간을 통한 급격한 화재확산으로 인해 화재진압이 매우 어렵다. 현재 국내 랙크식 창고의 소방시스템은 많은 문제점이 있으며, 이를 해결하기 위하여 새로운 소방시스템을 설계되고 개발되었다. 극 초기감지와 화재발생위치정보를 얻기 위하여 감지기 네트워크와 인공지능을 활용한 지능형 시스템을 설계되었다. 극초기에 화재 위치 인근에서 살수가 가능하도록 수직 일제살수 배관과 습식배관, 그리고 전자밸브를 사용하여 시스템을 구성하였다. 설계 결과를 기반으로 실제 시스템의 설치 및 실대형 시험을 진행하였으며, 성공적으로 시험이 완료되었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.514-519
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• 2009

The purpose of this study is to show the method of applying snow thermal storage system through the analysis of the cases in Japan. The results were as follows. (1) The systems in Japan were installed at the location whose annual mean air temperature was $14.6^{\circ}C$ or below and annual snowfall was 59 cm or above. (2) By analyzing the characteristics of the systems, meltwater circulation system with a backup chiller was confirmed to be most suitable for Korea. (3) For the first time in Korea, the system with the snow storage of 500 ton was designed at Muju after analyzing regional climate characteristics.

• Earthquakes and Structures
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• 제13권1호
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• pp.67-77
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• 2017

Oil storage tanks are vital life-line structures, suffered significant damages during past earthquakes. In this study, a numerical model for an unanchored vertical vaulted-type tank was established by ANSYS software, including the tank-liquid coupling, nonlinear uplift and slip effect between the tank bottom and foundation. Four actual earthquakes recorded at different soil sites were selected as input to study the dynamic characteristics of the tank by nonlinear time-history dynamic analysis, including the elephant-foot buckling, the liquid sloshing, the uplift and slip at the bottom. The results demonstrate that, obvious elephant-foot deformation and buckling failure occurred near the bottom of the tank wall under the seismic input of Class-I and Class-IV sites. The local buckling failure appeared at the location close to the elephant-foot because the axial compressive stress exceeded the allowable critical stress. Under the seismic input of Class-IV site, significant nonlinear uplift and slip occurred at the tank bottom. Large amplitude vertical sloshing with a long period occurred on the free surface of the liquid under the seismic wave record at Class-III site. The seismic properties of the storage tank were affected by site class and should be considered in the seismic design of large tanks. Effective measures should be taken to reduce the seismic response of storage tanks, and ensure the safety of tanks.