• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.36-44
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• 2017

The small commercial fuel cell is a new energy system that produces electricity and heat through electrochemical reaction between air and hydrogen. In Korea, hundreds of domestic small commercial fuel cell systems have been installed and operated every years and many parts in fuel cell systems depend on overseas products. KOGAS(Korea Gas Corporation) has developed the fuel processor which is an important part of fuel cell system and has evaluated the long-term durability. And KOGAS has evaluated domestic and overseas NG blower and fuel processor connected to NG blower. The fuel processor developed by KOGAS have maintained an efficiency of 76% and constant performance over 3,000 hours. The NG blower developed in Korea showed similar characteristics as overseas NG blower in the evaluation of power consumption according to rear pressure and outside temperature. The fuel processor module, fuel processor connected to BOP showed excellent performance.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.877-882
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• 2014

The reduction of CO2 emission has been discussed in the Marine Environment Protection committee in the International Maritime Organization as the biggest causes of GHG for the purpose of indexing CO2 amounts released into the atmosphere from ships. Accordingly, various methods including the change in the hull design to improve energy efficiency, the coating development to reduce friction resistances, the additives development for improving thermal efficiency in an engine, the low-speed operation to reduce fuel consumptions, and etc. have been applied. The main engine of a ship is an electronic engine for improving the efficiency of the whole load area. However, marine generator engines still use mechanical drive engines in intake, exhaust, and fuel injection valve drive cams. In addition, most of marine generator engines in ships apply a part-load operation of less then 80% due to an overload protection system. Therefore, marine auxiliary diesel engine set at 100% load is necessary to readjust in order to efficient operation because of part-load operation. The objective of this study is to report the results of the part-load fuel consumption improvement by injection timing readjust to identifying the operational characteristics of a marine generator engine currently operated in a ship.

• Journal of Trauma and Injury
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• v.32 no.4
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• pp.226-237
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• 2019

Purpose: This study investigated the characteristics of adult patients who had fallen from a height and presented to an emergency room (ER) according to gender and intentionality, with the goal of reducing the harm caused by these injuries. Methods: A retrospective analysis was conducted of fall-from-height patients aged ≥19 years from the in-depth surveillance study of injured patients visiting ERs conducted under the supervision of the Korea Centers for Disease Control and Prevention from 2011 to 2016. Patterns were analyzed according to gender and intentionality. Results: There were 29,838 men (68.5%) and 13,734 women (31.5%), with mean ages of 50.3±15.7 years and 57.2±19.9 years, respectively. The most common height of the fall was ≥1 m to 4 m in men (n=15,863; 53.2%) and <1 m in women (n=7,293; 53.1%). The most common location where the fall occurred was the workplace for men (n=10,500 male; 35.2%) and residential facilities for women (n=7,755; 56.5%). Most falls from height were unintentional (n=41,765; 97.1% vs. n=1,264; 2.9% for intentional falls). Suicide was the most frequent reason for intentional falls, and the age group of 19-30 years predominated in this category (n=377; 29.9%). For intentional falls, the most common interval before presentation to the ER was 0-6 hours (n=370; 29.3%) and the most common height was ≥4 m (n=872; 69.0%). Conclusions: Among men, falls from height most often occurred from ≥1 m to 4 m, at the workplace, and during the course of paid work, whereas among women, they were most common from <1 m, in residential facilities, and during daily activities. Intentional falls most often occurred with the purpose of suicide, in the age group of 19-30 years, with an interval of 0-6 hours until treatment, from ≥4 m, and in residential facilities. Alcohol consumption was more common in intentional falls.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.3
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• pp.25-34
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• 2018

This paper presents a heating source of carbon nanofibers for the efficiency and the drying performance of laundry dryer, and focuses on the applicability-evaluation of its source. To design the proposed heating module, experiments were conducted in terms of surface temperature and surface temperature distribution characteristics of carbon nanofiber lamps. The surface temperature of the lamps increased linearly with increment of a current to flow a lamp and revealing the increasing pattern as the length of the ramps is shorter. The proposed heating source was evaluated based on drying efficiency, moisture evaporation rate at laundry, and internal temperature of a drum during drying process. The drying efficiency satisfied a 45% which is specified in KS C 9319. The moisture evaporation rate and the internal temperature of the drum were respectively 98.88% and $61.1^{\circ}C$, which are similar to that of S's company dryer. From the evaluation and actual drying test results, the proposed carbon nanofiber lamp heating module is considered to be applicable as a heat source for laundry dryer in terms of drying efficiency and drying performance. it is possible to obtain a heat source at a high temperature, an excellent calorific value, an improvement in drying performance, and an effect of sterilizing laundry due to the emission of far-infrared rays. In addition to the applicability, the difference of the drying efficiency between the dryers was analyzed in detail based on the power consumption of the heat sources.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.75-84
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• 2018

Thermal stress of livestock has been issued due to recent climate change trends and this causes reproductive disorders, decreased feed consumption, immunosuppression, and increased mortality of animals. Concept of THI has been widely used to quantitatively evaluate the degree of thermal stress for animals, however use of this concept is restricted for animals living in the enclosed facilities such as mechanically ventilated broiler houses. In this study, time-based internal energy flow and variation trends of temperature and humidity were analyzed based on BES technique. Local weather data, insulation characteristics of building materials, heat and moisture generation rate from broilers according to age, algorithm of ventilation operation were adopted for boundary condition of the model to accurately compute THI values inside the mechanically ventilated broiler house. From the BES computation, excess frequency of THI threshold in Jeju city was highest on the assumption that air conditioning equipments were not installed. When general raising density ($39kg\;m^{-2}$) was adopted, total 2,191 hours were exceeded. Excess hours of THI threshold were strongly related to the cumulative air temperature ($R^2=0.87$).

• Journal of Biosystems Engineering
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• v.28 no.3
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• pp.217-224
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• 2003

To find out heating load and to determine the power of heat pump compressor for the Ondol room heating the COP of heat pump, the variation of Ondol room air temperature, the variation of ambient temperature and power consumption of heat pump are analyzed. The results from this study were summarized as follows: 1. The COP of the heat pump in close loop decreased as the ambient air temperature. The COP was 2.26 when the temperature difference of condenser was $20\pm3^{\circ}C$. 2. The Ondol surface temperature was $25\pm3^{\circ}C$ when the hot water of $40^{\circ}C$ was supplied from hot water storage tank to the Ondol and the temperature difference between the Ondol surface and the room air temperature was $7~8^{\circ}C$. 3. The ratio of thermal conduction heating load to total heating load in Ondol heating space was found to be 83% and ratio of ventilation heating load was 17%. Therefore, the thermal conduction heating load was confirmod to be a major heating load in Ondol heating space. 4. In case of the ambient temperature of $3.2^{\circ}C$, the efficiency of heat exchange of Ondol heating system was 85%. 5. The heating load per Ondol heating surface area and volume of Ondol room space were theoretically analyzed. In case of the room temperature of $20^{\circ}C$ and the ambient temperature of $-3.2~3.8^{\circ}C$, the heating load per Ondol surface area was 115.8~167.6kJ/h ㆍ㎥ and per Ondol mom space volume was 50.2~72.7kJ/h ㆍ㎥. 6. The compressor power of heat pump fur the Ondol room heating could be determined with the heating load analyzed in this study In case of the Ondol room air temperature of 17~2$0^{\circ}C$ and the ambient temperature of -5~3.8$^{\circ}C$, the compressor power of heat pump per Ondol surface area was analyzed to be $2.3\times10^{-2}psm^2$, and per volume of Ondol room space $1.0\times10^{-2}1.4\times10^{-2}ps/m^2$ps.

• Archives of design research
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• v.16 no.2
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• pp.281-290
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• 2003

In the knowledge and information-based age of today, it would be fair to say that the compatibility of each person, enterprise, and nation can be evaluated by how each of them manages and maintains the knowledge created from data and information. Since the importance and necessity of knowledge management has been acknowledged, there have been studies to create, apply, and evaluate the knowledge concerning design. Previous studies done on this subject can be divided into three main categories - CRM, online statistical research, and eCRM - according to the materials used to create knowledge. These studies are meaningful in that they can create knowledge in their respective fields, although they are somewhat inadequate because the designers can't create as much knowledge as can be applied in business; design-related consumers demand composite knowledge integrating the characteristics of all three fields. In other words, they want to know the ordinary customers'preferences in the previous off-line market in the CRM field, the research results of statistical questionnaires to the various elements of design in statistical research fields, and even the pattern of preference and consumption of many and unspecified persons transcending the time and place in eCRU field. This study proposes to solve the problem related with web-based design knowledge maintenance through the synthetic application of CRM, Statistical Research, and eCRM The information proposed in the solution can De expected to help designers working at design-related enterprises, as well as research institutes, to develop the knowledge necessary to design more consumer-oriented products.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.553-568
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• 2018

Popular music is a spce where intrinsic desires and values of young people are well exposed in its process of production and consumption. Previous discussions of Korean youth and youth culture have been proceeding mainly in the sense of their resistances to older generation. However, this is limited in that it neglects the inherent microscopic characteristics of youth culture. The purpose of this study is to investigate what the signs and discourses of youth generation make and share in popular music, and how it relates to social context through the 'Mimesis' theory. As a result, the songs of the 1990s remarkably showed the resistance to the old generation in its narrative structure and have signs which expresses repression and uniformity. On the other hand, the songs of the 2010s have many fragmented signs which has been reconstructed into individualized discourse structure. It is assumed that the songs have been able to gain a lot of empathy and popularity from the young generation by visualizing emotions and desires experienced by themselves in the social context. Through this study, it suggests to pay attention to the sensitivity, desire and creativity of young people in music in the social and cultural context of the time.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.499-512
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• 2020

The development of the economy and network environment has a great impact on physical stores, and physical bookstores are gradually upgrading and transforming with the pace of the times. This study takes the modern bookstore under the concept of the third space as the research object. The purpose of it is to understand the needs of consumers for the space of the modern bookstores, explore the characteristics and development direction of them, which provides theoretical guidance for the follow-up development of the modern bookstore. Based on the concept of the third space and the theory of lifestyle shops and reorganizing theoretical investigation and prior research, the researcher extracts the characteristic elements of modern bookstores in line with the concept of the third space. Moreover, the research analyzes five bookstores opened in large-scale commercial facilities after 2010 as research cases. Through the analysis of the results, it shows that the modern bookstore is a multi-functional and compounded space which is gradually transformed from a single bookseller to a seller of selling lifestyle proposal. And through the analysis of big data to predict the changes in market consumption, we can find out the different needs of consumers, so as to carry out the targeted design of bookstore space and then improve the value of it. In the context of the co-development of economy and culture, the transformation of modern bookstores actually conforms to the change of consumer demand and realizes a virtuous circle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.601-610
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• 2020

Recently, damage caused by drought is becoming worse and worse due to the global climate change. To overcome these problems, movable-weir to control the water level has been installed instead of a fixed-weir made from concrete. On the other hand, it is difficult to operate an existing moveable-weir because of the high cost of facility management and manpower consumption. In addition, because most moveable-weirs are installed in power systems, the operating cost and the cost of connection for power systems increase when they are located in remote areas. Therefore, this paper proposes an optimal design algorithm and the evaluation algorithm of the SOC (state of charge) of a lithium-ion battery to replace an existing power supply with eco-friendly movable-power with a power supply system using PV modules and lithium-ion batteries. In addition, this study modeled a 50kW power supply system of a movable-weir using PSCAD/EMTDC S/W. The simulation results confirmed that the proposed algorithm has stable operation characteristics in an independent operation mode and interconnection operation mode and that there is the possibility of commercialization with a benefits evaluation of the eco-friendly power supply system of a movable-weir.