• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.2
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• pp.72-78
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• 2014

In a cold chain, the refrigerator is also employed for defrosting, by using an electric heater, which consumes 15% of the power for the system operation. In this study, the condensation heat of the refrigerant was suggested as the heat source of defrosting heat, instead of that from an electric defrost heater. The heat for defrosting was stored to a phase change material (PCM, NMP : $52^{\circ}C$) in thermal storage, and was periodically supplied to the evaporator by a circulation loop of brine. As a result, a defrost time by the PCM was obtained that was less than or equal to that by the electric heater. Moreover, power consumption during defrosting was saved by up to 99% of that of the electric heater.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.449-453
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• 2009

기존 주택 및 고층건물화재에서 발생하는 화재 폭발 사고에 대해서는 많은 연구가 이루어지고 있으나, 이천 냉동창고 화재와 같이 많은 인명피해가 발생되는 작업환경에서의 화재 특히 밀폐공간에서의 화재 폭발 위험성 및 특성은 주택 및 고층건물화재에 비교하여 높은 폭발위험성 및 빠른 화염전파 특성을 보이나 이에 관한여 구체적인 연구는 미비한 실정이다. 본 연구는 밀폐공간 작업환경에서의 화재 폭발 위험성 특성 분석을 위하여 밀폐공간에서 작업 시 발생되어지는 가연성 가스의 확산 특성 분석 및 폭발 위험성 분석 방법에 관한 연구와 밀폐공간에서의 화염 확산 특성에 관한 연구논문 이다.

• Journal of Institute of Convergence Technology
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• v.2 no.1
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• pp.1-6
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• 2012

The cold chain system in South-East Asia is requiring to maintain freshness of refrigerated or frozen food. In this study, Thermal storage system using Phase change material (PCM) was developed and evaluated its performance about temperature and cold keeping time. For various application of cold chain system, we developed portable cold box, cold roll container and freezing station. Keeping time on laboratory tests of portable cold box in case of refrigeration and freezing were 6 hours and 4 hours, respectively. Cold container was developed to 2.5 ton scale. Evaluation in Indonesia, it was showed to keep the setting temperature of $-10^{\circ}C$ over 40 hours at $30^{\circ}C$ of ambient air. Freezing station using PCM was kept over 24 hours under $-20^{\circ}C$.

• The Korean Journal of Food And Nutrition
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• v.16 no.4
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• pp.397-405
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• 2003

The cleanness of Korean(n=292), Chinese(n=46), Japanese(n=114) and Western(n=74) styles restaurants in 25 districts in Seoul was evaluated in terms of kitchen area(6 criteria), handling of raw materials(3 criteria), hygiene practice for cook(1 criteria), treatment of wastes(2 criteria) and hall(2 criteria). The western-style restaurants were scored the highest points in all criteria. The other three restaurants were poorly evaluated compared with western-style ones in kitchen area, including cleanness of inside of the kitchen, hygiene practice, ventilation and working environment, drainage, and storage of utensils. The most critical criterion which represents the overall evaluation was the ventilation and working environment of the kitchen for Chinese, Japanese and Western-style restaurants, and was the cleanness of inside the kitchen for Korean-style restaurants.

• Tunnel and Underground Space
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• v.12 no.3
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• pp.142-151
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• 2002

Claesson(2001)'s analytical solution, and two numerical models with Dirichlet and Neuman interior boundary condition respectively were investigated to estimate the transient temperature distribution with distances from the Taejon underground food cold storage pilot cavern. Claesson's solution, which is based on constant temperature boundary condition at the rock wall during a temperature decline step, showed relatively good agreement with temperature measurements in the rock mass in order of average error difference, 0.89$\^{C}$ without any adjustments on laboratory thermal properties to represent the rock mass. For the numerical model with heat flux through the rock wall, a boundary condition setting technique was newly proposed to overcome the difficulty of prescribing variable convective heat tranfer coefficient and far-field air temperature inside the cavern as they may be certainly changed according to the cooling-down time. The results showed also good agreement with measurements in order of average error difference, 1.58$\^{C}$, and were compared to those of the numerical model with fixed temperature at the rock wall. Finally, the most proper procedure to precisely predict the temperature profile around a cavern was proposed as a series of analysis steps including an analytical exact solution and numerical models.

• Journal of Food Hygiene and Safety
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• v.22 no.1
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• pp.63-75
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• 2007

A survey on sanitary management at 98 food service institutions located in Jeollabuk-Do were conducted. Food service institutions included 13 hospitals, 38 schools, 40 enterprises, and 7 others. The sterilization in boiling water was used for disinfection of tableware, spoon and chopsticks, and dish towel. Cooking kit, refrigerator, chopping board, and knife were sterilized with disinfectant. Frequency of sanitary training program on employees was 56.1% for 1 time/month, 12.2% for 2-3 times/month, and 11.3% for 1 time/week. Preparing ratio of defrosting, warehouse and rest room, and washing and sterilization diary were 73.8, 60.5, and 54.5%, respectively. However, checking ratio of environments (9.5%), personal sanitation (10.8%), and sanitary training program diary(8.4%) were low. Major obstacle factors on the introduction of Hazard analysis critical control point (HACCP) system into food service institutions were lack of equipment and facilities (54.1%) and lack of understanding and data on HACCP system (17.3%). Therefore, in order to reduce the outbreak of food-borne diseases increasing frequency, we estimated that the introduction of sanitary management system and the conversion of dietician' perception on sanitary managements in food service institutions were needed.

• Fire Science and Engineering
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• v.30 no.4
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• pp.73-81
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• 2016

A self-regulating heating cable is an electrical heating element by flowing an electric current between parallel conductors filled with an extruded semi-conductive polymer. Self-regulating heating cables are used mainly for frost protection purposes because the construction is convenient and the price is low. On the other hand, structural problems with imperfections of the insulation can cause a fire despite their usefulness. This paper deduced a direct method to derive the cause by investigating the scene of a fire due to a self-regulating heating cable and analyzed the basic problem using fault tree analysis. In this paper, the actual fire scene was a cold storage warehouse, and fire investigation was conducted. After investigating the fire scene and fault tree analysis, the cause of the fire could be attributed to dielectric breakdown of the self-regulating heating cable. This paper could be utilized in the fire safety activities and similar fire investigations.

• Korean journal of food and cookery science
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• v.26 no.5
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• pp.603-616
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• 2010

Based on recent dramatic increases in foodborne outbreaks in restaurants, self-managed sanitation systems are now recommended to control contributing risk factors. This study aimed to improve sanitation management practices in restaurants and had two objectives. First, we tried to develop a self-managed sanitation check-list, including risk factors contributing to foodborne illness and Korean food hygiene regulation articles. We also tried to evaluate current sanitation management practices in restaurants according to operation and restaurant type. Thirty restaurants were evaluated by on-the-spot inspectors using an auditing tool consisting of four dimensions, seventeen categories, and forty-one items. Total compliance rate categorized by operation type significantly differed between chain restaurants and self-managed restaurants, with values of 85.5% and 51.6%, respectively. Therefore, self-managed restaurants, which showed the lowest compliance rate of below 30.0%, need more strict control to improve current unsanitary management practices, specifically relating to 'sterilization of knives, chopping boards, and wiping cloths', 'sanitation training', 'not allowing access into the kitchen to outsiders', 'handling of food or utensils on shelves at a 15 cm distance away from floor', 'prevention of cross-contamination of cooked foods or vegetables', and 'records of kitchen access or inspection'. Thus, an effective food sanitation system is essential and should be implemented to improve the existing sanitary conditions in restaurants. However, the most important factor to achieving food sanitation management objectives is food handlers' self-motivation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.602-612
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• 2010

This study was conducted to investigate the state of hygiene education aimed for by bakers, and the evaluations of the importance and the performance concerning sanitary characteristics by the bakers. The questionnaires were administered to 186 bakers in Busan and the data evaluated by 5 scales method of Likert were statistically analyzed. 20.4% of bakers have not received hygiene education. Only 32.8% of bakers have experienced hygiene education regularly. The more the bakers were educated, the more they practiced the contents of hygiene education. The major reason of education unfulfilment was due to insufficient equipments and facilities. The scores of the hygienic performance of educated bakers were significantly (p<0.05) higher than those of uneducated bakers in food sanitation, especially for sanitary characteristics on inspection, pre-preparation and distribution. The mean scores of the importance and the performance evaluated by bakers were 4.05/5.00 and 3.76/5.00, respectively. The bakers assessed the highest scores on the importance and the performance of personal hygiene. The gap score was -0.30 between the importance and the performance for sanitary characteristics. The baker recognized that sanitary management was not performed as much as they recognized its importance. The importance and the performance grid of bakers revealed that the items of checking the certification for the origin of new food ingredient, inspecting deliveries as quickly as possible, separation between preparing and breading time, thawing frozen food under running tap water/in refrigerator, separating disposal gloves and utensils by the purpose, putting products in cleaned and sterilized utensils, letting consumes know the expiration date of products, preventing a rubber hose from being left on the kitchen floor, checking insect nets frequently and so on showed lower scores compared to the mean scores of the importance and the performance. The levels of the hygienic performance by bakers were positively correlated (p<0.01) with the recognitions of the importance on sanitary characteristics. These results might provide basic data for hygienic training and play a role on the improvement of the sanitary management in bakery.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.4
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• pp.577-586
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• 2011

This study was carried out to investigate food service management practices in various operation types of child care center in Gyeonggi area of Korea, and to provide basic information for improving food service management policies at child care centers. Self-administrated questionnaires were collected from 102 child care center directors. The statistical analysis was completed using SPSS ver. 18.0 program. Approximately 97.1% of the directors were women. The number of total children were difference in public, private and home care centers respectively (p<0.001), and time of operation was significantly (p<0.01). Only 8.9% of the centers employed a dietitian, whereas 92.5% of the centers employed cook or assistant cook, thus food service was not managed by professionals in most centers. All of the centers had been self-operated and meals were prepared in a conventional manner. In approximately 89.2% of the centers servings snacks twice a day. Menu planner of the centers which have no dietitian was the child care information center (47.5%) or the director (34.7%). In most centers, the directors was also purchasing manager and 36.0% of the center purchased food every day. These results indicated that food service management guidelines need to be established by the child care center type with the government control and financial support. We recommended that they furnish the efficient food service program for food service management.