• Journal of Power Electronics
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• v.16 no.2
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• pp.666-674
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• 2016

In this paper, a high efficiency satellite electrical power supply system is proposed. The increased efficiency of the power supply system allows for downscaling of the solar array and battery weight, which are among the most important satellite design considerations. The satellite power supply system comprises two units, namely a generation unit and a storage unit. To increase the efficiency of the solar array, a maximum power point tracker (MPPT) is used in the power generation unit. In order to improve the MPPT performance, a novel algorithm is proposed on the basis of the hill climbing method. This method can track the main peak of the array power curve in satellites with long duration missions under unpredicted circumstances such as a part of the array being damaged or the presence of a shadow. A lithium-ion battery is utilized in the storage unit. An algorithm for calculating the optimal rate of battery charging is proposed where the battery is charged with the maximum possible efficiency considering the situation of the satellite. The proposed system is designed and manufactured. In addition, it is compared to the conventional power supply systems in similar satellites. Results show a 12% increase in the overall efficiency of the power supply system when compared to the conventional method.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.2
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• pp.27-35
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• 2006

Large dams are managed with operation standard and flood forecasting systems, while small dams do not have management method generally. Shortage of water resources and natural disasters due to drought and flood raised public concerns for management of small dams. Most of small dams are irrigation dams, which need diversified water uses. However, the lack of systematic management of small dams have caused serious water wastage and increased natural disasters. Storage management method and system were developed to solve these problems in small dams. The system was applied to Seongju dam for effective management. The storage management method was established considering hydrology simulation and statistical analysis using the system. This method can bring additional available water, even in the same conditions of the water demand and the supply conditions of watershed. It can improve the flood control capacity and water utilization efficiency by' the flexible operation of storage space.

• Preventive Nutrition and Food Science
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• v.5 no.3
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• pp.177-178
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• 2000

Chemical and photochemical precesses during food storage an preparation rapidly degrade $\beta$-carotene, the most active form of carotenoids. We investigated the possibility of liposomes as tool to preserve $\beta$-carotene. Liposomes with $\beta$-carotene were prepared as multilamellar vesicles by using soybean phosphatidylcholine, in terms of the ratio of $\beta$-carotene to phospholipid and pH. Incorporated efficiency was 99.7% at 1:0.05 of phospholipid : $\beta$-carotene and at pH 9.0. As the concentration of $\beta$-carotene increased, the incorporated efficiency increased progressively. pH did not affect the incorporation efficiency greatly.

• Journal of the Korea Safety Management & Science
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• v.21 no.4
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• pp.75-80
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• 2019

Sales of the Korean clothing industry grew to 16.9 percent on-year in 2010, but the growth rate dropped to 3 percent from 2011 to 2016 and the overall market began to slump to 1.1.6 percent in 2017. The competitiveness of clothing companies is also a major sector in logistics capability, and the average logistics cost of domestic clothing companies is 8.3 percent of sales in 2011, higher than the average 8 percent of domestic industries, and 36.4 percent of the total storage cost in 2011, higher than the 28.8 percent share of the total storage cost of domestic companies. As domestic production conditions such as wage hikes and labor disputes worsened in the 1990s, production facilities were rapidly moved overseas, which led many clothing companies to have no production facilities or a minimal production base in Korea and focus on marketing and design capabilities. The total storage capacity and storage efficiency of the logistics center became very important as the products were changed to the form of mass warehousing and small-volume forwarding. Research shows that building column spacing, a model of this research, can affect the amount of hanger rack storage empirically, so for sustainable growth of clothing companies, it is necessary to improve competitiveness in the logistics market by reducing costs and improving efficiency to overcome difficulties in corporate management. Because logistics costs are 8.3 percent and operating profit to sales ratio is 2 percent, it is expected that operating profit will increase by 41.5 percent if logistics costs are reduced by 10 percent. If 10% of storage cost is saved based on storage cost, operating profit is expected to increase by 15% To strengthen the competitiveness of the clothing industry, a reduction in logistics costs is essential. Therefore, the purpose of this study is to provide hints that logistics experts can have empirically small amounts in reducing storage costs through column spacing adjustment of logistics centers that have not been dealt with statistically until now, and to contribute to the continued growth of clothing companies and the development of the domestic logistics industry.

• The Transactions of the Korea Information Processing Society
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• v.13 no.3
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• pp.102-110
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• 2024

Blockchain records all transactions issued by users, which are then replicated, stored, and shared by participants of the blockchain network. Therefore, the capacity of the ledger stored by participants continues to increase as the blockchain network operates. In order to address this issue, research is being conducted on methods that enhance storage efficiency while ensuring that valid values are stored in the ledger even in the presence of device failures or malicious participants. One direction of research is applying techniques such as Reed-Solomon encoding to the storage of blockchain ledgers. In this paper, we apply Reed-Solomon encoding to the key-value store used for ledger storage in an open-source blockchain, and measure the storage efficiency and increasing computational overhead. Experimental results confirm that storage efficiency increased by 86% while the increase in CPU operations required for encoding was only about 2.7%.

• Korean journal of food and cookery science
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• v.19 no.1
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• pp.83-95
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• 2003

Investigations were conducted on the changes in carotenoids content, and quantification of cis-trans-${\beta}$-carotene Isomers in pureed and cooked carrot and spinach during storage. The isomerization and degradation of carotenoids were monitored by high-performance liquid chromatography on a C$\_$30/ reversed-phase column with diode-array detection. The results showed that lutein, ail-trans-${\beta}$-carotene, ${\alpha}$-carotene, 9-cis-${\beta}$-carotene and 13-cis-${\beta}$-carotene were present in carrot and spinach. Zeaxanthin and cryptoxanthin were present in raw spinach. The contents of lutein, zeaxanthin, cryptoxanthin, ${\alpha}$-carotene and all-trans-${\beta}$-carotene in pureed and cooked carrot and spinach decreased with increasing storage period. The 9-cis and 13-cis carotenoid isomers were the major types formed in cooked carrot during storage. Cooking was not found to alter the carotenoid profile of the sample, but increased the total amount of carotenoids compared with pured ones. This increase could be explained that cooking itself increased the extraction efficiency and inactivated the enzymes degradating carotenoids.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.9
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• pp.703-711
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• 1991

In this paper, an efficient storage reclamation algorithm for RISC parallel processing in the object orented programming environments is presented. The memory management for the dynamic memory allocation and the frequent memory access in object oriented programming is the main factor that decreases RISC parallel processing performance. The proposed algorithm can be efficiently allocated the memory space of RISCy computer which is required the frequent memory access, so it can be increased RISC parallel processing performance. The proposed algorithm is verified the efficiency by implementing C language on SUN SPARC(4.3 BSD UNIX).

• Journal of the Korean Solar Energy Society
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• v.35 no.5
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• pp.21-29
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• 2015

In this study, the performance of hybrid solar air-water heater when the heated air was used as inlet air was investigated during air and liquid were heated simultaneously. Temperature difference between inlet air and ambient was set as $0^{\circ}C$, $13^{\circ}C$ and $22^{\circ}C$ and it was maintained during the daily operation. As a result, thermal efficiency of liquid heating was increased when the inlet air temperature was increased and heat gain of the water in heat storage tank was also increased with increment of temperature difference between inlet air and ambient temperature. On the contrary to this, the decrement of air heating efficiency and total efficiency of collector was confirmed with increment of inlet air temperature and it is considered that heat gain of liquid side is lower than heat loss of air side that occurring by using heated air as inlet air of collector. So, from these results, maximum temperature that the liquid in heat storage tank can reach was expected to increase if the return air or any heated air was used as inlet air. But air and total efficiency of hybrid solar air-water is decreased, so using outdoor air as inlet air is considered as better way on perspective of using of solar thermal energy by hybrid solar collector. However, it is hard to conclude that using outdoor air is better than heated air on the perspective of energy saving of building because the performance of heat storage performance was increased even air and total thermal efficiency was decreased, so the necessity of more profound consideration about these result in further research was confirmed for putting the hybrid solar air-water heater to practical use.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.330-335
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• 2017

Increased fossil fuel consumption causes global warming, environmental pollution, and abnormal climate change. Wind-generated power installation is proposed to solve this problem. Recently, the wind power plant construction case encourages the installation of the energy storage system (ESS) to improve the intermittency of wind power. The maximized ESS operation profits connected to wind power are not generated in the simplest operation pattern of charging at night and discharging at day. The battery charging efficiency improvement should be considered to get more profits. Thus, there is a possibility of increasing ESS operation profits by analyzing the battery AC and DC charging/discharging efficiency and the yearly average sealed maintenance free (SMP) in hours. In this paper, the battery impedance characteristic, AC and DC charging/discharging efficiency, and the yearly average SMP are analyzed. The operation scenario to improve the ESS battery charging efficiency connected to wind power is proposed and verified via simulation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.104-118
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• 1995

This study was performed to evaluate factors affecting desorption of organic solvents collected on charcoal tube and to find out the optimum condition. Desorption efficiency for polar analytes was improved when several polar desorption solvents such as methanol, dimethylformamide(DMF), 2-(2-butoxyethoxy)ethanol were added to carbon disulfide($CS_2$). The best improvement was achieved when 10% dimethylformamide(DMF) in $CS_2$ was used as desorption solvent. During storage of polar analytes, recovery was greatly reduced. Especially, the recovery of cyclohexanone was decreased to 18.1 % after a month storage at $34^{\circ}C$. After two weeks storage, recovery of polar analytes was sharply decreased. Water adsorbed on charcoal interfered the recovery of polar analytes but didn't interfere that one of nonpolar solvent, toluene. When 10% DMF in $CS_2$ was used as desorption solvent, the effect of water on recovery was decreased, comparing with Desorption efficiency increased when analyte loading increased, and usage of 10% DMF in $CS_2$ decreased the loading effect. Increasing volume of desorption solvent was not effective to improve desorption efficiency of analytes when 10% DMF was used. Continuous shaking and sonication is not helpful to increase the desorption efficiency of analytes except cyclohexanone using 10% DMF. When silica gel used as adsorbent, methanol was better desorbent than dimethylsulfoxide. Analytes adsorbed on silica gel showed high recovery in low concentration and less affected by humidity. On the basis of this study, the following conclusions have been drawn. To improve the recovery of polar organic materials in air samples, it is necessary to analyze samples as soon as possible after they were collected. Otherwise, samples must be stored at low temperature. Using two components of desorption solvents, such as 10% DMF in $CS_2$, the effects of loading and humidity decreased for polar analytes such as methyl ethyl ketone and methyl isobutyl ketone. When work place has high humidity with low concentration of polar organic solvents, silica gel can be used as adsorbent, because it produces quantitative recovery for polar analytes at this condition. But it should be noted that high humidity makes breakthrough easy in silica gel samples.