• Journal of the Korea Society for Simulation
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• v.26 no.2
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• pp.41-49
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• 2017

In the acquisition program, the conceptual design is the most important step toward specifying the military objectives, establishing requirements and determining future developmental directions, of a target system. However, if both the requirements and directions are incorrectly set due to the lack of development experiences and literature backgrounds in the target systems, such as future ground combat vehicles, it may become a major risk in the future design phases and the entire acquisition program. In order to correct these errors in the future phases, time, effort and cost are required. Therefore, it is necessary to reduce the errors that occur in the initial stages to effectively acquire the future ground combat vehicles. This paper describes the initial design method for verifying the requirements and the developmental directions and estimating the system performance at the conceptual design through the system-level physical modeling and simulation (M&S) and the target system performance analysis. The system-level physical M&S use cutting-edge design tools, model-based designs and geometric-based designs. The system performance estimation is driven from the results of the system-level physical M&S and the specialized system analysis software.

• Journal of Korea Water Resources Association
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• v.51 no.9
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• pp.769-782
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• 2018

Estimation of design floods is typically required for hydrologic design purpose. Design floods are routinely estimated for water resources planning, safety and risk of the existing water-related structures. However, the hydrologic data, especially streamflow data for the design purposes in South Korea are still very limited, and additionally the length of streamflow data is relatively short compared to the rainfall data. Therefore, this study collected a large number design flood data and watershed characteristics (e.g. area, slope and altitude) from the national river database. We further explored to formulate a scaling approach for the estimation of design flood, which is a function of the watershed characteristics. Then, this study adopted a Hierarchical Bayesian model for evaluating both parameters and their uncertainties in the regionalization approach, which models the hydrologic response of ungauged basins using regression relationships between watershed structure and model. The proposed modeling framework was validated through ungauged watersheds. The proposed approach have better performance in terms of correlation coefficient than the existing approach which is solely based on area as a predictor. Moreover, the proposed approach can provide uncertainty associated with the model parameters to better characterize design floods at ungauged watersheds.

• Food Science and Preservation
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• v.24 no.6
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• pp.778-785
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• 2017

This study was conducted to develop a predictive model for the growth of Escherichia coli strain RC-4-D isolated from red kohlrabi sprout seeds. We collected E. coli kinetic growth data during red kohlrabi seed sprouting under isothermal conditions (10, 15, 20, 25, and $30^{\circ}C$). Baranyi model was used as a primary order model for growth data. The maximum growth rate (${\mu}max$) and lag-phase duration (LPD) for each temperature (except for $10^{\circ}C$ LPD) were determined. Three kinds of secondary models (suboptimal Ratkowsky square-root, Huang model, and Arrhenius-type model) were compared to elucidate the influence of temperature on E. coli growth rate. The model performance measures for three secondary models showed that the suboptimal Huang square-root model was more suitable in the accuracy (1.223) and the suboptimal Ratkowsky square-root model was less in the bias (0.999), respectively. Among three secondary order model used in this study, the suboptimal Ratkowsky square-root model showed best fit for the secondary model for describing the effect of temperature. This model can be utilized to predict E. coli behavior in red kohlrabi sprout production and to conduct microbial risk assessments.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.1 s.28
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• pp.69-77
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• 2004

Since there are a lot of changes in climate on domestic and natural disasters owing to the disturbance-development of the land, damages of properties and human life frequently occur due to the coastal floodings. Accordingly, it is necessary to find the area where the danger of flooding coasts is relatively high and to inform resident the characteristics of the area As a part of preventive land management to minimize the flooding damages of the coastal area, this study suggested the generation of the coastal flood hazard map that provides detailed information such as refuge path, a place of refuge, and the location of medical supplies, food, and main rescue equipment, etc. This study selected the southern region of Daebu-do as an exemplary area, conducted a document study to establish GIS data, secured pre-structured data, and suggested the method of establishing GIS data fit to the study area. In particular, it emphasized the efficient construction of the geographical spatial data that were accurate, economic, objective, and realistic in supporting the modeling to predict the flooding zone. The specific type of established database was divided into flooding risk area, flooding warning area, and flooding-volume area. The prototype of coastal flood hazard map can be widely used for efficient disaster management. Furthermore, it is considered that the map could be applied for arousing residents' attentions to the flooding, prior education, and local governments' management actions against the danger of flooding.

• Korean journal of food and cookery science
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• v.19 no.4
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• pp.477-492
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• 2003

The purposes of the study were to establish HACCP-based standards and guidelines for conducting a plan review to build, or renovate, hospital food service establishments, and ensure the safety of foodservice and reduce the risk of food borne illness. The scope of the study included suggestion for the planning of hospital foodservice facilities: layout, design, equipment and modeling. The results of this study can be summarized as follows: 1) The development of a foodservice facility plan based on the results of a survey, literature reviews and the results of interviews with foodservice managers from 9 general hospitals. This was composed of operational policies in foodservices, layout characteristics, space allocation, selection, design, specification standards for equipment and the construction principles of foodservice facilities. 2) Two foodservice facility models were developed, one for general hospitals with 900 beds (2,000 patients and 2,500 employee meals per day) and the other for general hospitals with 300 beds (600 patients and 650 employees meals per day). 3) The suggested kitchen space requirements for the foodservice facility models were 341.2 ㎡ (W 17,100mm x L 23,700mm) and 998.8㎡ (W 35,600mm x L 32,800mm) for the 300 and 900 beds hospitals, respectively, with both designs being rectangular. The space requirements for the equipment, in relation to the total operational area, in terms of ratios were 1:3.5 and 1:3.8 for the 300 and 900 beds hospitals, respectively. The recommended space allowances per bed for the developed foodservice facility models were 1.15 ㎡ and 1.11 ㎡ for the 300 and 900 beds hospitals, respectively, which were increased by more than 30% compared to those suggested in the precedent study, and considered appropriate for the implementation of the HACCP system. 4) The hospital foodservice facilities plans and models were developed based on the general sanitation standards, guidelines and the HACCP system, and included foodservice facility layout, product flow, physical separation between contaminated and sanitary areas, foodservice facility specifications with a 1/300 scale for a 300 bed, and a 1/400 scale for a 900 beds blueprint. 5) The main features of the developed foodservice facility plans and models were; physical separation between contaminated and sanitary areas to prevent cross contamination, product flow in one direction from the arrival of the raw material to the finished product, and separation of different work areas and the process of receiving & preparation of products, refrigeration & storage, cooking, assembly, cleaning & disinfection, employee areas and janitorial facilities. The proposed models from this study were presented as examples for those wanting to build, or renovate, their facility for the production of foods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.141-155
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• 2016

This research is a descriptive study that aimed to identify the health knowledge and optimistic bias related to stroke of middle-aged adults and the effect these had on their health-promoting lifestyle. The research was conducted from July 15 to August 15, 2015. The research subjects were 191 adults aged between 40 to 60 years. A structured questionnaire was used and self-administered for data collection. The PASW Statistics 21.0 and AMOS 21.0 programs were used for data analysis, and analysis of variance, correlation analysis, and structural equation modeling analysis were conducted. It was found that the middle-aged adults recognized smoking and hypertension as higher risk factors for stroke than diabetes, and there was a slight optimistic bias for stroke. Health knowledge about stroke had correlations with optimistic bias (r = -.143, p = .048) and health-promoting lifestyle (r = .268, p = < .001), while optimistic bias had correlations with interpersonal relationships and stress (r = .177, p = .014) in health-promoting lifestyle. In addition, health-promoting lifestyle affected health knowledge more than optimistic bias. In conclusion, it was found that the active information acquisition, health knowledge, and optimistic bias of middle-aged adults toward stroke were important factors pertaining to a stroke-related health-promoting lifestyle. Therefore, an education program to improve the health-promoting lifestyle related to stroke in middle-aged adults should be considered as a way to enhance stroke-related health knowledge and reduce optimistic bias.

• Journal of Distribution Research
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• v.15 no.4
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• pp.87-117
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• 2010

'Entrepreneurship' which means spirit or activity seeking new value by challenging boldly the uncertainty is one of the most important concept in 21st century business environment. Franchise Industry taking a relationship with distribution industry also needs entrepreneurship. As franchise industry consists of small and medium enterprises, the entrepreneurship of franchisor's CEO is important for the franchisor's growth. The purpose of this study is to analyze the factors influencing on the entrepreneurship of franchisor's CEO, and the effect of the CEO's entrepreneurship on franchisor's performance. For this purpose, this study set CEO's psychological characteristics, market characteristics, and social-institutional characteristics as independent variables, CEO's entrepreneurship as parameter variables, and franchisor's performance as dependent variables. And to analyze this study model, this study collected questionnaires from 152 franchisors' CEOs, and uses SEM(Structural Equation Modeling). As the result, 'CEO's Entrepreneurship' influenced on both 'Franchisor's Financial Performance' and 'Franchisor's Non Financial Performance'. The results of this study provide some guides for franchisor's CEO and government policies.

• Journal of health informatics and statistics
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• v.42 no.4
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• pp.309-316
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• 2017

Objectives: Radon and its progeny pose environmental risks as a carcinogen, especially to the lungs. Investigating factors affecting indoor radon concentrations and models thereof are needed to prevent exposure to radon and to reduce indoor radon concentrations. The purpose of this study was to identify factors affecting indoor radon concentration and to construct a comprehensive model thereof. Methods: Questionnaires were administered to obtain data on residential environments, including building materials and life style. Decision tree and structural equation modeling were applied to predict residences at risk for higher radon concentrations and to develop the comprehensive model. Results: Greenery ratio, impermeable layer ratio, residence at ground level, daily ventilation, long-term heating, crack around the measuring device, and bedroom were significantly shown to be predictive factors of higher indoor radon concentrations. Daily ventilation reduced the probability of homes having indoor radon concentrations ${\geq}200Bq/m^3$ by 11.6%. Meanwhile, a greenery ratio ${\geq}65%$ without daily ventilation increased this probability by 15.3% compared to daily ventilation. The constructed model indicated greenery ratio and ventilation rate directly affecting indoor radon concentrations. Conclusions: Our model highlights the combined influences of geographical properties, groundwater, and lifestyle factors of an individual resident on indoor radon concentrations in Korea.

• 한국노년학
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• v.28 no.4
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• pp.969-989
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• 2008

This study attempts to explain how depression among community elderly relate to suicidal ideation and whether or not the psycho-social characteristics of elderly persons moderate the relationship between these two variables. This study was conducted in Seoul, Busan, and Daegu and included 273 persons 65 years and above who were using senior welfare centers in the communities. For the questionnaire and analysis, this research uses the Health Care, Life Event, Self-esteem, Family Assessment scales. This research utilizes a wide range of statistical analyses, such as descriptive analysis, Pearson's correlation, reliability analysis, multiple regression, and general linear modeling. The calculations employed the use of SPSS/PC+ 12.0. This research indicates, among other things, that elderly persons with a high level of depression and psycho-social characteristics show a tendency toward higher suicidal ideation and that the level of self-esteem, life event, and family communication plays a moderating role in the relationship between depression and suicidal ideation among community elderly. In conclusion, elderly persons who experienced with a high level of psycho-social characteristics shows a relatively greater tendency toward suicidal ideation when compared to elderly persons having a low level of psycho-social characteristics. The intervention's effectiveness in reducing suicidal ideation can reinforce self-esteem, and cope with stressful life events and family discord as prevention strategy to reduce risk factors for suicide in late life.

• Journal of the Korean Society of Child Welfare
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• no.53
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• pp.105-133
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• 2016

The purpose of this study was to examine the relationships among child abuse, depression, and smartphone addiction by gender. Data were gathered though questionnaires surveying 1,601 adolescents living in the Seoul and Kyeonggi areas. The results of t-tests and multiple regression analyses using structural equation modeling are as follow. First, approximately 40 percent of adolescents reported having experienced child abuse in the past year. Second, 24.5 percent of adolescents were found to be at risk of smartphone addiction. Third, child abuse was associated with depression and smartphone addiction among adolescents, and depression was found to have a mediating effect on the relationship between child abuse and smartphone addiction. Lastly, gender differences were also found: for male students, child abuse was directly related to smartphone addiction; for female adolescents, depression was found to mediate the relationship between child abuse and smartphone addiction. The results suggest different intervention strategies according to gender and a necessity of intervention to prevent child depression and smartphone addiction. The implications for social work practice were also discussed.