• 대한산업공학회지
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• 제27권2호
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• pp.169-175
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• 2001

Most of studies on automated storage/retrieval (AS/R) system assumed that storage capacity is given, although it is a very important decision variable in the design phase. We propose a simple algorithm to estimate the required storage capacity, i.e., number of aisles and number of openings in vertical and horizontal directions in each aisle, of an AS/R system under stochastic demand, in which storage requests occur endogenously and exogenously while the retrieval requests occur endogenously from the machines. Two design criteria, maximum permissible overflow probability and maximum allowable storage/retrieval (S/R) machine utilization, are used to compute the storage capacity. This model can be effectively used in the design phase of new AS/R systems.

• 한국시뮬레이션학회논문지
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• 제10권3호
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• pp.71-82
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• 2001

Considering material handling delay which occurs between storage and processing stations, we propose an algorithm to estimate the required storage capacity, i.e., number of aisles and number of openings in vertical and horizontal directions in each aisle, of an automated storage/retrieval(AS/R) system. Due to the random nature of storage and retrieval requests, proportion of single and dual commands is not known in advance. Two design criteria, maximum permissible overflow probability and maximum allowable storage/retrieval(S/R) machine utilization, are used to compute the storage capacity. Most of studies assume that storage capacity of AS/R systems is given, although it is a very important decision variable in the design phase. Therefore, the proposed model can be effectively used in the design phase of new AS/R systems.

• 한국농공학회논문집
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• 제63권5호
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• pp.49-62
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• 2021

The objective of this study was to evaluate the flood control capacity of the agricultural reservoir based on state-of-the-art climate change scenario - SSP (Shared Socioeconomic Pathways). 18 agricultural reservoirs were selected as the study sites, and future rainfall data based on SSP scenario provided by CMIP6 (Coupled Model Intercomparison Project 6) was applied to analyze the impact of climate change. The frequency analysis module, the rainfall-runoff module, the reservoir operation module, and their linkage system were built and applied to simulate probable rainfall, maximum inflow, maximum outflow, and maximum water level of the reservoirs. And the maximum values were compared with the design values, such as design flood of reservoirs, design flood of direct downstream, and top of dam elevation, respectively. According to whether or not the maximum values exceed each design value, cases were divided into eight categories; I-O-H, I-O, I-H, I, O-H, O, H, X. Probable rainfall (200-yr frequency, 12-h duration) for observed data (1973~2020) was a maximum of 445.2 mm and increased to 619.1~1,359.7 mm in the future (2011~2100). For the present, 61.1% of the reservoirs corresponded to I-O, which means the reservoirs have sufficient capacity to discharge large inflow; however, there is a risk of overflowing downstream due to excessive outflow. For the future, six reservoirs (Idong, Baekgok, Yedang, Tapjung, Naju, Jangsung) were changed from I-O to I-O-H, which means inflow increases beyond the discharge capacity due to climate change, and there is a risk of collapse due to dam overflow.

• 대한토목학회논문집
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• 제28권6C호
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• pp.379-388
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• 2008

대형말뚝기초의 양방향 재하시험에서 재하용량 기준이 정확하게 규정되어 있지 않다. 그래서 양방향말뚝재하시험을 수행함에 있어 많은 혼란이 발생하고 있으며 재하용량에서 최대 2배까지의 차이가 나타나고 있다. 본 연구에서는 양방향 말뚝재하시험 기준들을 고찰하였으며, 국내에서 수행된 양방향 말뚝재하시험 사례들에 기초하여 최대등가시험하중, 재하하중 증가비, 재하용량 증가비 및 설계하중 충족비를 분석하였다. 양방향 말뚝재하시험 기준은 1방향 재하용량으로 정의되어야 하며, 1방향 재하용량은 설계하중의 2배 이상 이어야 한다는 것을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.585-592
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• 2002

Discharge capacity of PBD is the most important factor of specification items to control any product of PBD. There is no standard specification for the PBD. Because the degree of discharge capacity is related to well resistance, install depth, maximum strain etc in the field. Discharge capacity test of PBD, permeability test of filter are conducted using PBD materials used in Korea. This paper proposes the critical discharge capacity for deep PBD under condition of non well resistance based upon their test and theoretical calculation. It was found that discharge capacity more than about 10 ㎤/sec is enough to undergo designing of deep PBD without well resistance.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.327-332
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• 1997

This study is aimed to investigate the effect of load and deflection on steel fiber reinforced concrete slab. Slabs were made with Hooked and Straight types steel fiber and compared a change of steel fiber contents and fiber types. Test were carried out to evaluate he first crack load, maximum load and deflection of slab. At the result, the first crack load, maximum load and energy absorption capacity were increased remarkably as steel fiber contents wee increased. And we found that the deflection of slab at same load ere decreased as steel fiber contents were increased, too. As the aspect ration was increased, the first crack load, maximum load and energy absorption capacity were increased.

• 한국대기환경학회지
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• 제15권5호
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• pp.649-655
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• 1999

Biofiltration of polluted gas streams contained $H_2S$ was studied. The experiments were performed in a laboratory-scale reactor with a porous ceramic media inoculated with sulfur oxidizing bacterium, TAS which was isolated from activiated sludge. The concentration of $H_2S$ in the inlet gas varied from 109 to 3,841 ppm, at the various space velocities(SV) of 50 $h^{-1}$ to 250 $h^{-1}$. Various tests have been conducted to evaluate the effects of such parameters as pH, concentration of sulfate ion and retention time on the pressure drop and maximum elimination capacity. The removal efficiency of $H_2S$ decreased as the $H_2S$ concentration or gas velocity increased in the inlet gas. Pressure drop was insignificant in this system. The maximum elimination capacity could reach up to 16.35g-S/kg-dry packing material/day.

• 대한산업공학회지
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• 제25권2호
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• pp.184-191
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• 1999

The k most vital arcs (k-MVA) of a maximum flow problem is defined as those k arcs whose simultaneous removal from the network causes the greatest decrease in the throughput capability of the remaining system between a specified pair of nodes. In this study, we present a method for determining all the k-MVA in maximum flow problem using a minimal cardinality cut algorithm and k-th minimal cut ranking algorithm. For ranking cardinality cuts, we use Hamacher's ranking algorithm for cut capacity and by comparing present residual capacity of cardinality cut with expected residual capacity of next cardinality cut, we also present termination condition for this algorithm. While the previous methods cannot find all the alternatives for this problem, a method presented here has advantage of determining all the k-MVA.

• Journal of Information Processing Systems
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• 제16권6호
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• pp.1261-1270
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• 2020

The physical security layer of industrial wireless sensor networks in the event of an eavesdropping attack has been investigated in this paper. An optimal sensor selection scheme based on the maximum channel capacity is proposed for transmission environments that experience Nakagami fading. Comparing the intercept probabilities of the traditional round robin (TRR) and optimal sensor selection schemes, the system secure performance is analyzed. Simulation results show that the change in the number of sensors and the eavesdropping ratio affect the convergence rate of the intercept probability. Additionally, the proposed optimal selection scheme has a faster convergence rate compared to the TRR scheduling scheme for the same eavesdropping ratio and number of sensors. This observation is also valid when the Nakagami channel is simplified to a Rayleigh channel.

• 한국전문물리치료학회지
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• 제4권3호
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• pp.17-33
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• 1997

The objective of this study was to identify pulmonary functional variations in relation to postural changes, lapse after changing position, and the use of abdominal band in the cervical cord injured. The subjects of this study were 19 quadriplegic patients who had been admitted to the department of the Rehabilitation Hospital, College of Medicine, Yousei University, from April, 1997 through May 3, 1997. A spiroanalyzer was used to measure pulmonary function in supine, standing, time after changing position, and recording to the position, application method, and tightness of the abdominal band. The data were analyzed by the repeated measure one-way ANOVA, and Wilcoxon signed rank test. The findings were as follows: 1. All phase of the patients' pulmonary function improved significantly in supine posture in contrast to standing (vital capacity by $0.46{\ell}$ and expiratory reserve volume by $0.09{\ell}$). 2. The longer the time lapsed from supine posture to standing, the patient's expiratory reserve volume, maximum ventilation volume, vital capacity, and forced expiratory volume increased. 3. When the patient lay in supine position, the maximum ventilation volume, vital capacity, and the forced vital capacity increased then the center line of the abdominal band was placed along iliac crest; on the other hand, when the patient was standing, placing the bottom line of the abdominal band along iliac crest increased the maximum ventilation volume, vital capacity, and forced expiratory volume. 4. In placing the abdominal band in the patients, leaving space between the top and bottom lines of the band helped increased in maximum ventilation volume, vital capacity, and forced vital capacity for patient in supine as well as in standing. 5. When placing the abdominal band to patients in supine posture, reducing the length of the band by 2.5% along the patient's waist line increased the patients' vital capacity, while reducing the length by 10% to patients in standing increased the maximum ventilation volume. The abdominal band should be placed in such a way that the bottom part of the band should be more tightly fastened while leaving enough room for a hand to be placed in between the body and the band for the top part of the hand. It should also be noted that in a supine position, the bottom line of the band should be placed along the iliac crest, while in standing, the center line should be placed along the iliac crest. The length of the band should also be reduced by 2.5% of the waist line in supine position, and in standing, the length should be reduced by 10%. It should also be noted that the pulmonary function of the patients should be measured at least 10 minutes after one position change.