• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.564-570
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• 2020

In order to propose a realistic demand forecast for harbor pilots, define a direction for securing a supply of pilots for the betterment of national logistic services, and ensure the competitiveness of Korean ports, this study intended first to propose a new forecasting process for harbor pilot requirements through conducting analysis of determining factors affecting harbor pilot demand. Additionally, analyzing relevant previous studies allowed us to estimate the number of pilots required in the past and asses the studies limitations. Our second purpose was to propose a more stable allocation method among different pilot areas after forecasting the demand of harbor pilots until 2027 through application of the new forecasting process. From this application, the total number of pilots required was forecasted at 270, suggesting the total demand for harbor pilots will be increased by 7.57% compared with 251 pilots in 2018.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1890-1896
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• 2006

Lumostatic operation for cultivation of Haematococcus pluvialis was assessed to test the scale-up strategy of photobioreactors. Lumostatic operation is a method of maintaining a proper light condition based on the specific light uptake rate ($q_e$), by cells. Lumostatic operations were performed in 0.4-, 2-, 10-, and 30-1 scale bubble column photobioreactors and the results were compared with cultures illuminated with constant light intensity. Significant differences were observed in the maximal cell concentrations obtained from 0.4-, 2-, 10-, and 30-1 scale photobioreactors under constant light intensity, yielding the maximal cell concentrations of $2.8{\times}10^5$, $2.2\times10^5$, $1.5\times10^5$, and $1.1\times10^5$ cells/ml, respectively. The maximal cell concentration in a 0.4-1 photobioreactor under lumostatic operation was $4.3\times10^5$ cells/ml. Furthermore, those in 2-, 10-, and 30-1 scale photobioreactors were about the same as that in the 0.4-1 photobioreactor. The results suggest that lumostatic operation with proper $q_e$ is a good strategy for increasing the cell growth of Haematococcus pluvialis compared with a constant supply of light energy. Therefore, lumostatic operation is not only an efficient way to achieve high cell density cultures with minimal power consumption in microalgal cultures but it is also a perfect parameter for the scale-up of photobioreactors.

• Journal of the Society of Disaster Information
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• v.20 no.2
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• pp.448-461
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• 2024

Purpose: The purpose of this study is to establish a life zone class suitable for Korean characteristics in the post-COVID-19 era and to classify the types for the installation and operation of living SOC facilities. Method: The concept of the life zone was established through policies and previous studies related to the life zone, and data in various fields such as population, employment, transportation, economy, and education were classified using the z-score technique. Result: Korea's life zones can be classified into metropolitan life zones, regional life zones, urban life zones, village life zones, and neighborhood life zones, and depending on their roles, they can be classified into central life zones, workplace-residential balanced life zones, residential life zones, industrial life zones, and low-density life zones. Conclusion: The results of this study show that proper life zone establishment and proper living SOC supply can prevent the decline of underdeveloped areas and contribute to balanced regional development

• Korean Journal of Construction Engineering and Management
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• v.11 no.1
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• pp.142-150
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• 2010

The purpose of this study is to analyze maintenance costs and estimation of elemental costs for educational buildings. The adapted research method selected four school buildings in seoul region as BTL projects. On the basis of the selected case, the study suggested a model to establish a system for each parts and estimate analyzed construction costs and maintenance costs according to that system. According to the analysis, the study proposed a partial construction costs analysis table and maintenance costs table and analyzed proper construction costs and maintenances costs. The results of this study are as follows 1) The average ratio followed by calculation of partial construction costs of the four school buildings are as followings. The total construction costs is analysed 6,666million won and each part of average rations is structure 47.15%, exterior of building 8.34%, interior of building 23.37%, electricity & fire fighting facility 5.74%, water supply & healthy facility 4.27%, heating & water supply facility 5.25%, landscape 1.36%, civil engineering works 4.51%. 2)The average ratio followed by analysis of partial maintenance costs of the four school buildings are as followings. The total maintenance costs is analysed 4,309 million won and each part of average ratio is exterior of building 11.02%, interior of building 41.81%, electricity & fire fighting facility 14.81%, water supply & healthy facility 11.22%, heating & water supply facility 12.76%, landscape 5.75%, civil engineering works 2.63%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4260-4266
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• 2015

In this study, the optimal control method for minimizing of energy consumption for central cooling system with proper occupant comfort level is researched by simulation. The optimal control method is that the optimal set temperatures such as the condenser water temperature, supply air temperature, and chilled water temperature with environment variable change such as outdoor air dry-bulb and wet-bulb temperatures are obtained by suggested optimal control algorithm with maximum and part building load. The TRNSYS program is used for system modeling and the control performances with the suggested optimal control method are compared with the existing control method of fixed set points. The suggested optimal control method shows better responses in energy consumption in comparison with existing control ones.

• Journal of the Korean Solar Energy Society
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• v.30 no.3
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• pp.33-38
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• 2010

The evaporative desalination system using solar thermal energy would be the efficient and attractive method to get fresh water from brine due to low carbon dioxide generation. In this research the solar desalination system as a heating source of refrigerant R123 in the evaporator was considered. The circulation of refrigerant in the evaporator can reduce the energy consumption of the system, because of using the latent heat of the refrigerant 123 instead of the sensible heat of present hot water. The system was comprised of the single-stage fresh water production unit on the capacity of 1ton/day with shell and tube type evaporator, heaters instead of solar collector to supply the proper heat to refrigerant, and refrigerant and brine circulation systems. Various operating flowrate and temperature ranges were varied in the experiments to get the optimum design data. The results showed that the optimum flow rate of brine feed rate to evaporator was 1.2Liter/min, and the yield of fresh water was increased as higher temperature of feed brine. It was confirmed that the circulation flowrate of heating source of refrigerant was decrease of one fifth of the present warm water system, and very efficient system for solar desalination.

• Journal of Animal Science and Technology
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• v.60 no.8
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• pp.20.1-20.4
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• 2018

Platelet rich plasma (PRP) is popularly used in the horse industry to enhance regeneration of tissue injury that has limitation of blood supply. This study aimed to compare the methods for platelet rich plasma preparation since they has not been established yet. Blood was collected from six horses and platelets were concentrated by three different methods (2-step centrifugation, separated centrifugation and separated centrifugation using histopaque). Concentrated blood was analyzed using Advia hematology systems. In the result, separated centrifugation with histopaque showed the significantly lower number of red blood cells than other groups. The 2-step centrifugation showed the significantly higher number of white blood cells than other groups, while it contained the highest concentration of red blood cells among three groups. In the 2-step centrifugation, separated centrifugation and separated centrifugation with histopaque, platelets were concentrated 4.5, 5.3 and 5.6 times, respectively. And no significant difference of the platelet concentration between the three groups was found. This study demonstrated that separated centrifugation using histopaque was the best method for platelet rich plasma preparation because of the proper amount of platelets and the separation of red blood cells from platelet rich plasma.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.662-673
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• 2012

This study introduces a condition diagnosis technique for a turbine governor system. The governor system is an important control system to handle turbine speed in a nuclear power plant. The turbine governor system includes turbine valves and stop valves which have their own functions in the system. Because a turbine governor system is operated by high oil pressure, it is very difficult to maintain under stable operating conditions. Turbine valves supply oil pressure to the governor system for proper operation. Using the pressure variation of turbine and governor valves, operating conditions of the turbine governor control system are detected and identified. To achieve automatic detection of valve status, time-based and frequency-based analysis is employed. In this study, a new approach, wavelet decomposition, was used to extract specific features from the pressure signals of the governor and stop valves. The extracted features, which represent the operating conditions of the turbine governor system, include important information to control and diagnose the valves. After extracting the specific features, decision rules were used to classify the valve conditions. The rules were generated by a decision tree algorithm (a typical simple method for data-based rule generation). The results given by the wavelet-based analysis were compared to detection results using time- and frequency-based approaches. Compared with the several related studies, the wavelet transform-based analysis, the proposed in this study has the advantage of easier application without auxiliary features.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.46
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• pp.159-177
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• 2010

This work intends to study some problems in relation to the issuance of letters of credit. Those problems are the delay of issuing letters of credit, the reissuing letters of credit, and the issuing letters of credit in the third party's name. Sellers and buyers must keep in mind that the supply of letter of credit by buyer is the condition precedent for a seller's shipment obligation. A seller has no obligation to ship the goods until he receives the letter of credit by buyer's bank, issuing bank. An issuing bank can have the risk that an original letter of credit and a reissued letter of credit can be used double in the exporting country. The most safe method for issuing bank is to cancel the original letter of credit and to reissue a new letter of credit. When an issuing bank issues a letter of credit in the third party's name, the bank should investigate the background of the transaction and give the buyer a proper line of credit.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.48-50
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• 2005

New environment change of electric power system focused in consumer's energy supply and demand. But electric power reliability preservation and reliability improvement countermeasure also need for long-term. It is need that change equipments that is composing electric power system in well-timed time and by maintaining, prevent breakdown beforehand and prevent consumer's power interruption by equipment fail. However, as only quantitative estimation is available by reliability estimation method that is presented in existing, it is no to use in dictionary fault prevention. Therefore, applied optimum reliability preservation through existent equipment fault data analysis of electric power system in equipment replace side, and this when maintain equipment replace of electric power system for reliability preservation using responsiveness analysis to base ordering evaluate. In existing about main equipment plain that this paper is power system the valued failure rate use this by score and precedence of electric power system equipment for replace of system considered expense.