• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.40-45
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• 2002

An AS/RS construction cost minimization model under throughput rate requirement constraint has been developed, whose objective function includes S/R machine cost, storage rack cost, and interrace conveyor cost. S/R machine cost is a function of the storage rack height, the unit load weight, and the control logic used by the system, while storage rack cost is a function of the storage rack height, the weight and the volume of the unit load. Since the model is a nonlinear integer programming problem which is very hard to solve exactly with large problem size, a solution procedure is developed to determine the height and the length of the storage rack with a fixed number of S/R machines, while increasing the number of S/R machines one by one to meet the throughput rate requirement.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.5 no.6
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• pp.1-6
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• 1982

The objective of this thesis to Provide a better insight into the effect of the amount of in-process storage has on the efficiency of production line with variable operation times. It is assumed that the material enters the line at the first work station and is then processed progressively through the line until it exits at the last work station, a finite amount of in-process storage is provided before all but the first work station of the line and the operation time of the work stations are statistically independent and follow exponential distribution. Under the above assumption, optimum allocation model is developed and following two approaches are used : 1) Given the available storage capacity, optimum allocation which minimizes the number of items in the line. 2) Given the available storage capacity, optimum allocation which. maximizes the utilization factor of the line. In a balanced three stage line, the production line efficiency is maximized under both categories when the second in-process storage is larger than the first.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2449-2456
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• 2013

The column-oriented database storage is a very advanced model for large-volume data analysis systems because of its superior I/O performance. Traditional data storages exploit row-oriented storage where the attributes of a record are placed contiguously in hard disk for fast write operations. However, for search-mostly datawarehouse systems, column-oriented storage has become a more proper model because of its superior read performance. Recently, solid state drive using MLC flash memory is largely recognized as the preferred storage media for high-speed data analysis systems. In this paper, we introduce fast column-oriented data storage model and then propose a new storage management scheme using a cross compressed replication for the high-speed column-oriented datawarehouse system. Our storage management scheme which is based on two MLC SSD achieves superior performance and reliability by the cross replication of the uncompressed segment and the compressed segment under high workloads of CPU and I/O. Based on the results of the performance evaluation, we conclude that our storage management scheme outperforms the traditional scheme in the respect of update throughput and response time of the column segments.

• Journal of the Korea Society for Simulation
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• v.21 no.2
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• pp.91-101
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• 2012

Automobile manufacturing consists of body-line, painting-line, and assembly-line. These production lines are disposed in series and go through a flow process, so according to the status of pre & post processing, a suspension happens in a line by a starvation(impossibility of production by insufficient supply) or blocking(impossibility of production by exceed capacity). Therefore, to prevent a loss of production coming from a starvation or blocking, a storage such as WBS or PBS is independently owned and operated. The paper suggests the simulation model of integrated storage which can operate it by integrating each storage performing a role as a buffer of line. Specifically, the paper found the answers about reasonable number of Stacker Crane and AGV(Automatic Guided Vehicle) and suggested a methodology of operation which is available to operate them. Also, it compared an efficiency between a model of current storage and integrated storage through simulation. As a result, it turned out that the model suggested in the paper was more efficient on suspension of painting-line stop than a current storage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.96-104
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• 2017

A one-shot system (device) refers to a system that is stored for a long period of time and is then disposed of after a single mission because it is accompanied by a chemical reaction or physical destruction when it operates, such as shells, munitions in a defense weapon system and automobile airbags. Because these systems are primarily related with safety and life, it is required to maintain a high level of storage reliability. Storage reliability is the probability that the system will operate at a particular point in time after storage. Since the stored one-shot system can be confirmed only through inspection, periodic inspection and maintenance should be performed to maintain a high level of storage reliability. Since the one-shot system is characterized by a large loss in the event of a failure, it is necessary to determine an appropriate inspection period to maintain the storage reliability above the reliability goal. In this study, we propose an optimal inspection policy that minimizes the total cost while exceeding the reliability goal that the storage reliability is set in advance for the one-shot system in which periodic inspections are performed. We assume that the failure time is the Weibull distribution. And the cost model is presented considering the existing storage reliability model by Martinez and Kim et al. The cost components to be included in the cost model are the cost of inspection $c_1$, the cost of loss per unit time between failure and detection $c_2$, the cost of minimum repair of the detected breakdown of units $c_3$, and the overhaul cost $c_4$ of $R_s{\leq}R_g$. And in this paper, we will determine the optimal inspection policy to find the inspection period and number of tests that minimize the expected cost per unit time from the finite lifetime to the overhaul. Compare them through numerical examples.

• Journal of Hydrogen and New Energy
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• v.21 no.4
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• pp.249-257
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• 2010

In this paper, a three-dimensional hydrogen absorption model is developed to precisely study hydrogen absorption reaction and resultant heat and mass transport phenomena in metal hydride hydrogen storage vessels. The 3D model is first experimentally validated against the temperature evolution data available in the literature. In addition to model validation, the detailed simulation results shows that at the initial absorption stage, the vessel temperature and H/M ratio distributions are uniform throughout the entire vessel, indicating that the hydrogen absorption is so efficient during the early hydriding process and thus local cooling effect is not influential. On the other hand, nonuniform distributions are predicted at the latter absorption stage, which is mainly due to different degrees of cooling between the vessel wall and core regions. This numerical study provides the fundamental understanding of detailed heat and mass transfer phenomena during hydrogen absorption process and further indicates that efficient design of storage vessel and cooling system is critical to achieve fast hydrogen charging and high hydrogen storage efficiency.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.697-700
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• 2005

Aquifer Thermal Energy Storage (ATES) system can be very cost-effective and renewable energy sources, depending on site-specific parameters and load characteristics. In order to develop an ATES system which has certain hydrogeological characteristics, understanding of the thermo hydraulic processes of an aquifer is necessary for a proper design of an aquifer heat storage system under given conditions. The thermo hydraulic transfer for heat storage is simulated using FEFLOW according to two sets of pumping and waste water reinjection scenarios of heat pump operation in a two layered confined aquifer. In the first set of model, the movement of the thermal front and groundwater level are simulated by changing the locations of injection and pumping well in seasonal cycle. However, in the second set of model the simulation is performed in the state of fixing the locations of pumping and injection well. After 365 days simulation period, the temperature distribution is dominated by injected water temperature and the distance from injection well. The small temperature change is appears on the surface compared to other slices of depth because the first layer has very low porosity and the transfer of thermal energy are sensitive at the porosity of each layer. The groundwater levels and temperature changes in injection and pumping wells are monitored to validate the effectiveness of the used heat pump operation method and the thermal interference between wells is analyzed.

• Journal of Biosystems Engineering
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• v.33 no.5
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• pp.309-316
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• 2008

The goal of this study was to develop prediction models to estimate the storage days of tomato. The transmittance spectral data measured on tomato were preprocessed through normalization, SNV, Savitzky-Golay, and Norris Gap and then were used to build the prediction models using partial least square (PLS) method. For the experiments, the tomato samples of different varieties were collected at different harvest time. The samples were taken right after harvest from the field and then were stored in a low-temperature storage room in which room temperature was maintained at $10^{\circ}C$. The transmittance spectral data of the tomato samples were measured at three-day intervals for 16 days. The performance of the prediction models was affected by the preprocessing techniques as well as the varieties and harvest time of the tomato. The best model was found when SNV was applied. The accuracy of the best model was 90.2%. It can be concluded that the transmittance spectra are useful information for predicting the period of storage of tomato.

• The Korea Journal of Herbology
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• v.27 no.5
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• pp.37-44
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• 2012

Objectives : The present study was undertaken to determine whether the ethanol extact of Citri Pericarpium (CP, Pericarp of Citrus unshiu Markovich, Rutaceae) is effective against atopic dermatitis according to it's storage period. Methods : To evaluate antiallergic effect of CP and OCP (Old Citri Pericarpium) evaluated in vivo their inhibitory effects against passive cutaenous anaphylaxis (PCA) reaction induced by IgE-antigen complex and scratching behaviors by compound 48/80. The Anti-atopic effects were measured by contact dermatitis, prurient animal model and PCA reaction. Contact dermatitis in mice as a model of the Type IV reaction caused by Oxazolone. Results : The results showed that anti-pruritus effects, analgesic effects of CP was depends on its hesperetin contents. And It also showed that keep longer in storage appeared to be higher in hesperetin contents. Both CP and OCP(Old CP) have a dose-dependent analgesic action in acetic acid induced writhing syndrome. OCP Potently inhibited PCA reaction in mice, although OCP weakly inhibited in long term contact dermatitis model in mice. Conclusions : These results suggest that the Proportional to the storage period, Citri Pericarpium possesses analgesic effects and anti-allergic effects.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.724-726
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• 1996

In this paper, we propose an optimal daily operation model for the total energy system which includes cogeneration, thermal storage and electrical charger and ice storage facilities. Storing and utilizing the surplus thermal and electrical energy, the daily operation cost could be reduced and more efficient use of thermal energy could be achieved. The ice storage cooling system has a merit of reduce the electricity cost by time of day rate(peak/off-peak). And also, refrigerator can be down sized compare to the other cooling system From this model, operation costs of the sample cogeneration system with/without auxiliary facilities are obtained and compared to each other. In case study, the sensitivity of operating cost is simulated according to the variation of cogeneration production cost, electricity rate, etc.