• 상하수도학회지
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• 제29권1호
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• pp.11-21
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• 2015

When designing Water Distribution System (WDS), determination of life cycle for WDS needs to be preceded. And designer should conduct comprehensive design including maintenance and management strategies based on the determined life cycle. However, there are only a few studies carried out until now, and criteria to determine life cycle of WDS are insufficient. Therefore, methodology to determine life cycle of WDS is introduced in this study by using Life Cycle Energy Analysis (LCEA). LCEA adapts energy as an environmental impact criterion and calculates all required energy through the whole life cycle. The model is build up based on the LCEA methodology and model itself can simulate the aging and breakage of pipes through the target life cycle. In addition the hydraulic analysis program EPANET2.0 is linked to developed model to analyze hydraulic factors. Developed model is applied to two WDSs which are A WDS and B WDS. Model runs for 1yr to maximum 100yr target life cycle for both WDSs to check the energy tendency as well as to determine optimal life cycle. Results show that 40yr and 54yr as optimal life cycle for each WDS, and tendency shows the effective energy is keep changing according to the target life cycle. Introduced methodology is expected to use as an alternative option for determining life cycle of WDS.

• 동아시아식생활학회지
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• 제21권1호
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• pp.125-133
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• 2011

This study was carried out to strengthen productivity and employee management through the development of simple pre-processed foods based on Hansik (Korean foods) and to investigate the utilization of fresh vegetable menus, pretreatment, and cooking time in the preparation of vegetable side dishes. The reasons for not using pretreated foods were increased cost, required product size is not available, and not hygienic. The acceptable rate of increase in cost when purchasing simple pre-processed foods was under 10%. The expected developed products of simple pre-processed vegetable foods were balloon flower root salad, seasoned green vegetables, and sheredded white radish. The expected developed products of simple mixed vegetable pre-processed foods were deodeok+balloon flower root and white radish+pear. Based on these findings, to increase the utilization of simple preprocessed foods, development of various product sizes and sauces is needed, cost must be reduced, and hygiene improved.

• 동아시아식생활학회지
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• 제21권1호
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• pp.1-13
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• 2011

The number of North Korean refugees residing in the Republic of Korea (South) has reached 17,000, and this number is expected to exceed 20,000 (North Korean Supporter's Association, 2009). Refugees have developed improper dietary habits while hiding and escaping North Korea. They have also developed preferences for exotic food. This thesis attempts determine the changes in Korean food. This study also describes the view on South Korean food by North Korean refugees. According to our survey, women refugees had better dietary habits than men. Moreover, women and those in their 40's showed a tendency to choose food based on quality over quantity. Both men and women refugees responded that they cook food based on North Korean recipes. Those who view their current financial status as average or higher stated that South Korean food is tastier than North Korean food. Those whose financial status among North Koreans was average or higher when they lived in North Korea appreciated the splendor and beauty of South Korean food more. The results of this study are expected to assist in determining the differences in dietary habits between those from the North compared to Koreans living in the Republic of Korea. Therefore, studies between South and North Korean food should continue.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2011년도 춘계학술발표대회 논문집
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• pp.65-68
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• 2011

The average increase in life expectancy obtained as a gift of modern science cannot hold itself responsible for extended life's happiness. It admits of no argument that the necessity of social preparation for minimizing bad health and longevity of unhappiness to aged people who are in the state of these continuous growth. Recently, because of an aging trend, targeting on elderly housing expected continuous increased demand in housing market, this study is to comprehend it's characteristic and offer implications. For the characteristic of elderly housing, firstly it needs scientific analysis of related theory and analysis of statistical data. Also this study aims to look through and suggest an alternative included the special matters of Korean society with advanced foreign country's analysis of an alternative. And judging from economic characteristics of elderly housing to be presented as an important factor, choices of housing according to economic level are anticipated to show different forms. In future, to supply elderly housing, therefore, the introduction of the concept of housing providing various opportunity of choice is necessary. If studies proceed through expanded alternative, it is judged to be able to draw more varied results in elderly housing. Also, if going along with political dimension study, it is expected to offer more specific and effective solutions of the problem of elderly housing.

• 응용통계연구
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• 제19권2호
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• pp.217-230
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• 2006

본 연구에서는 낮은 이항비율에 관한 구간추정을 위해서 어떤 신뢰구간이 바람직한지를 살펴보았다. 실제 적으로 희귀질병, 특정 산업재해율, 그리 고 기생충에 관한 실태조사를 위해서 대규모 표본조사가 실시된다. 표본 규모가 크고, 0 < p ${\leq}$ 0.1인 상황에서 모비율 p의 추정에 바람직한 신뢰구간을 살펴보았다. 위의 조건에서 6가지의 신뢰구간들에 대해 평균포함확률과 평균제곱오차의 제곱근, 그리고 평균기대폭을 사용한 결과 Mid-p 신뢰 구간이 가장 바람직하고 다음으로 AC, score와 Jeffrey 신뢰 구간들이 적절한 것으로 밝혀졌다.

• 동아시아식생활학회지
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• 제19권2호
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• pp.278-286
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• 2009

Restaurants have two strategic levers for revenue management: duration control and demand-based pricing. Reducing dining times, especially during peak periods, can add considerable revenue for restaurants. Managing meal duration, however, can be far more complex than manipulating the price. This paper examines dining duration expectations for restaurants types(Family, Korean, Quick service restaurant), customers characteristics(gender, age, occupation, meal period, visiting frequency, dining occasion, dining companions) using an a adaptation of a price sensitivity measurement tool, naming it 'Time Sensitivity measurement tool' or TSM. The TSM is then used to derive the optimal time points, and the range of acceptable times. The results demonstrate that there is a relatively wide spread of acceptable dining duration times in family restaurant. Furthermore, the optimal time points was shorter than the mean expected dining times, which suggests that many restaurants may be able to shorten dining duration without compromising customer satisfaction. The paper explores whether demographic and dining variables have an impact on time preferences, and finds whether gender, age, meal periods, visiting frequency, and dining companion effects are significant. Specifically, women in their thirties tended to prefer a significantly longer dining times for dinner.

• 한국기계가공학회지
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• 제19권2호
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• pp.47-54
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• 2020

Themo-mechanical analysis was carried out using the finite element method for the steel shell of a cupola furnace. When the outer surface of the shell was cooled with water to within the temperature range of 35-80 ℃ during operation of the cupola, the inner surface of the shell was expected to exhibit a temperature of 65-248 ℃ based on heat transfer analysis. The shell was also expected to have an equivalent stress range of 100-280 MPa in the outer surface over the temperature range examined. Upon cooling the shell to obtain an outer surface temperature <80 ℃, the maximum equivalent stress of the shell did not exceed the yield strength. Although the temperature of the outer surface varied between 35 and 80 ℃ periodically due to the cooling control problem, the fatigue stress at the outer surface of the shell was calculated to be within the fatigue strength. During a non-operational period to examine the system between furnace operations, the thermal stress presented in the shell was sufficiently low to reach the desired yield strength and fatigue limit.

• 한국기계가공학회지
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• 제17권4호
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• pp.150-159
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• 2018

The present research deals with a finite element analysis and fatigue evaluation of a steam separator of a high-pressure evaporator for the Heat Recovery Steam Generator (HRSG). The fatigue during the expected life of the HRSG was evaluated according to the ASME Boiler and Pressure Vessel Code Section VIII Division 2 (ASME Code). First, based on the eight transient operating conditions prescribed for the HRSG, temperature distribution of the steam separator was analyzed by a transient thermal analysis. Results of the thermal analysis were used as a thermal load for the structural analysis and used to determine the mean cycle temperature. Next, a structural analysis for the transient conditions was carried out with the thermal load, steam pressure, and nozzle load. The maximum stress location was found to be the riser nozzle bore, and hence fatigue was evaluated at that location, as per ASME Code. As a result, the cumulative usage factor was calculated as 0.00072 (much less than 1). In conclusion, the steam separator was found to be safe from fatigue failure during the expected life.

• 한국초등과학교육학회지:초등과학교육
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• 제18권2호
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• pp.103-117
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• 1999

The importance of pedagogical content knowledge(PCK) has been recognized in learning science teaching. PCK is based partly on the essence of subject matter knowledges. Therefore, the effective teaching of science content knowledges is fundamental in preservice education of student teachers. But, particularly the science curriculum of primary teachers' colleges is composed of less lessons than needed. This research was executed to identify the content and context of earth science which were contained in questions by student teachers These questions which were written by the students about the earth science content in elementary science texts and teachers' guide books were collected and analyzed. Frequency and context concentration of questions about the themes of contents were obtained. In each unit of the text books, scatter diagrams of question frequency and context concentration of themes showed various features. The main results were as follows. first, in case of the units which contents ate composed of themes expected to be experienced in everyday life, the question frequency and context concentration showed positive correlation between them. But, other units, which everyday life experiences are not expected to influence, did not show distinct correlation.

• 대한지역사회영양학회지
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• 제5권2호
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• pp.333-342
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• 2000

The purpose of this study was to evaluate microbiological quality for each stage of the kimbap manufacturing process in summer and winter. Under the various controlled conditions through the simulation, the time-temperature data were collected and the microbiological quality(including total plate count, coliforms, and fecal coliform count) were evaluated. To determine the expected shelf life of Kimbap, a microbiolgical analysis according to the length of the storage time was performed. The microbiological analysis on both sanitary and unsanitary utensils was compared. The microbiological quality of the raw materials of Kimbap in summer was not at an acceptable level, but that of the heat-treated raw materials of Kimbap met the requirement according to the standards set by the Natick Research Center. The number of the microorganisms of the unsanitary utensils and the Kimbap made from unsanitary utensils was more than the acceptable criteria. Sanitary management is necessary to prohibit cross-contamination and to manufacture Kimbap safely. Results from storage times and storage temperature conditions(chilled and room-temperature storage) showed that the expected shelf-life of the Kimbap with the room-temperature storage was as less than 3 hours in summer, while it was as 7-10 hours in winter.