• 대한조선학회논문집
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• 제48권6호
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• pp.509-515
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• 2011

The radar cross section (RCS) of warships is a crucial design factor to improve the survivability in terms of not only low observablity of the platform but also efficiency of on-board sensors and jamming devices against enemy threat. In design stage, numerical models are generated in order to quantitatively assess RCS, of which hull surfaces are modeled with the finite number of the flat plate. However, in practice, hull surfaces are permanently deformed by various kinds of loads such as winds and ocean waves faced during operations. In this paper, the effect of these shell plate deformation to RCS is numerically investigated. For this purpose, RCS calculations are carried out for various kinds of numerical models, such as single plates, dihedrals, large-sized undulate plates, and virtual warships, with some extent of permanent deformation. The results are compared with those of corresponding models without permanent deformation. It is concluded that the permanent deformation of hull surface highly influences RCS characteristics of warships, therefore they should be considered in the RCS analysis.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권6호
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• pp.762-781
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• 2018

This paper presents the ballistic armor performance examination and thickness estimation for the latest naval ship structure materials in the Republic of Korea. Up to date, research regarding methods of ballistic experiments establishing database on the latest hull structure materials as well as a precise method of estimating required thickness of armor against specific projectiles have been rarely researched. In order to build a database and estimate proper thicknesses of structure materials, this study used four structure materials that have been widely applied in naval ships such as AH36 steel, AL5083, AL5086, and Fiber Reinforced Plastics (FRP). A $7.62{\times}39mm$ mild steel core bullet normally fired by AK-47 gun was considered as a threat due to its representativeness. Tate and Alekseevskii's penetration algorithm was also used to calculate a correction factor (${\alpha}$) and then estimate the armor thickness of naval ship hull structure materials with a given impact velocity. Through live fire experiments, the proposed method performance difference was measured to be 0.6% in AH36, 0.4% in AL5083, 0.0% in AL5086, and 8.0% in FRP compared with the experiment results.

• 기술혁신학회지
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• 제7권1호
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• pp.64-88
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• 2004

This paper aims at investigating which factors play important roles in selecting government's new core IT industries and how competitive they are. We surveyed 6 competitiveness factors and 17 IT industries for the expert group. The logit and probit models were estimated and SWOT analysis was performed. The empirical results show that government put emphasis on marketability, externality and technology, not publicity, when selecting IT new core industry. The skilled human resources turn out to be a threat factor in the government selected IT new core industries such as home-network, third generation semi-conductor. Therefore, training or education system for skilled labors is required to develop and nurture such industries. The contribution to small medium venture industry and publicity are lower in the several industries such as intelligent service robots, post PC, embodied S/W, next generation battery, which are selected by government, not by standardized data based criterion. in such industries, marketabilities, technology, skilled human resources are threats factors to such industries. Therefore every effort for enhancing the marketability and R&D investment and education system for skilled labor are necessary to develop the industries.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.518-520
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• 2014

레이더를 이용하여 표적을 탐지함에 있어 표적의 Radar Cross Section(RCS)은 매우 중요한 요소이다. 동일한 표적이라도 레이더를 바라보는 방향에 따라 RCS 값이 크게 차이 나며, 레이더로 표적을 탐지하는 확률을 높이기 위해 RCS가 크게 나타나는 곳에 레이더를 배치하는 것이 유리하다. 북한의 탄도미사일은 우리의 안보에 큰 위협이 되고 있으며, 탄도미사일 방어를 위해 레이더를 이용하여 미사일을 조기에 탐지하여 추적하여야한다. 본 논문에서는 탄도미사일의 RCS 특성과 북한 탄도미사일의 탄도를 분석하여 탄도미사일의 탐지확률을 높이기 위한 레이더 배치 방안을 제시하였다.

• 한국수산과학회지
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• 제54권5호
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• pp.596-616
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• 2021

A global increase in fish consumption has led to a rapid expansion of aquaculture production, which has been linked to enhancing the spread of infectious diseases. Viral diseases can cause high mortality in many cultured fish species, posing a serious threat to the aquaculture industry. Infectious hematopoietic necrosis virus (IHNV) is one of the primary threats to aquacultured salmonid species, causing huge economic losses. Since the first report in cultured sockeye salmon Oncorhynchus nerka during the 1950s in North America, IHNV has spread to other regions, including Europe, Asia, South America, and Africa by transportation of infected fish and eggs, causing disease and increasing mortality in a wide variety of salmonid species. Here, we review existing information relevant to IHNV: its phylogenetic characteristics, origin, infection history, virulence determinants, susceptible hosts, vectors, and vaccine development. This review also addresses a possible cross-species transmission of IHNV to a new host, olive flounder Paralichthys olivaceus, a cultured fish of economic importance in East Asian countries.

• Nutrition Research and Practice
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• 제15권3호
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• pp.346-354
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• 2021

BACKGROUND/OBJECTIVES: While the use of food additives in food processing has become a common practice worldwide, consumers' worry about potential hazards has not diminished. The purpose of this study was to identify trends in South Korean parents' perceptions about food additives by analyzing the results of surveys conducted from 2014 to 2018. SUBJECTS/METHODS: We conducted an off-line survey in Korea annually between 2014 and 2018 on perceptions about food additives. The numbers of survey respondents in each year from 2014 to 2018 were 381, 426, 301, 519, and 369, respectively. Our consumer respondents were parents of elementary-school-aged children. RESULTS: The ratios of respondents perceiving "food safety" as the most important factor in purchasing processed foods and "food additives" as the biggest threat to food safety have decreased over the years. However, most consumers still have negative perceptions of food additives. Additionally, among consumers lower confidence in or trust of the Korean government continued throughout the study period and appeared to be the main problem that needs to be overcome. CONCLUSIONS: This study found that Korean parents are still troubled by food additives. Consumers' confidence in the government needs to be increased through public communications. More multifaceted educational programs communicating scientific knowledge of food additives are needed in order to correct consumers' misperceptions.

• Nutrition Research and Practice
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• 제15권sup1호
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• pp.70-78
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• 2021

BACKGROUND/OBJECTIVES: The recent coronavirus disease 2019 pandemic has brought to light issues regarding personal and environmental cleanliness. Individuals may have concerns about cleanliness at food service establishments when they consume food prepared at a restaurant. In Korea, a new restaurant hygienic certificate system was implemented in 2017. The effect of this new system has not been evaluated. SUBJECTS/METHODS: This study investigated consumers' perceptions of these new certificates using the protection motivation theory (PMT). An online survey was conducted to collect data and then exploratory factor analysis, analysis of variance, and multiple regression tests were run. RESULTS: The results of this study indicate that 3 different certificates had significant differences in threat (P < 0.001) and benefit (P < 0.001) perception. However, experience with a foodborne illness from a restaurant did not effect on the PMT variables. In addition, the 3-tier certificate did not motivate consumers to protect themselves against foodborne illnesses, while previous experiences of foodborne illness (P < 0.05), coping (P < 0.001), and benefits (P < 0.01) affected this protection motivation. CONCLUSIONS: This study suggests that consumers were not influenced by different certificate levels regarding their motivation to protect themselves from foodborne illnesses. Therefore, an improved plan should be initiated to clarify the meaning of these certificates. The results of this study can help the application and development of a new system for future adaptations.

• 한국해양공학회지
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• 제37권4호
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• pp.145-157
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• 2023

Due to a recent increase in maritime activities in South Korea, the frequency of maritime distress is escalating and poses a significant threat to lives and property. The aim of this study was to validate a drift trajectory prediction technique to help mitigate the damages caused by maritime distress incidents. In this study, OpenDrift was verified using satellite drifter data from the Korea Hydrographic and Oceanographic Agency. OpenDrift is a Monte-Carlo-based Lagrangian trajectory modeling framework that allows for considering leeway, an important factor in predicting the movement of floating marine objects. The simulation results showed no significant differences in the performance of drift trajectory prediction when considering leeway using four evaluation methods (normalized cumulative Lagrangian separation, root mean squared error, mean absolute error, and Euclidean distance). However, leeway improved the performance in an analysis of location prediction conformance for maritime search and rescue operations. Therefore, the findings of this study suggest that it is important to consider leeway in drift trajectory prediction for effective maritime search and rescue operations. The results could help with future research on drift trajectory prediction of various floating objects, including marine debris, satellite drifters, and sea ice.

• 융합경영연구
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• 제3권4호
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• pp.5-11
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• 2015

The study examined the socio-economic factors influencing the participation of rural farming households in barter trade in Ondo State, Nigeria. The objectives were to compare the socio-economic characteristics of the participants and non-participants in barter trade, analyze the preference for barter trade and identify the constraints to it. Also, the factors affecting respondents' participation in barter trade were identified. Empirical results indicated that there were significant differences in the socio-economic characteristics of the participants and non-participants in barter trade. The SWOT analysis showed that possession of agrarian attributes by the locality where the trade is practiced was the strongest factor ensuring the survival of barter in the study area. Double coincidence of wants was found to be the most prevailing weakness associated with barter while the major reason for participation by some households was that the quantity of commodities received is usually higher compared with cash transactions. Transportation cost to barter markets was found to be the greatest threat to the continued existence of barter trade in the area. The results of the Probit model showed that age, household size, transportation cost to cash markets, farm size, distance to barter markets, and formal education significantly affected the probability participating in barter trade.

• 한국식생활문화학회지
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• 제21권2호
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• pp.131-141
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• 2006

The purpose of this research is to develop the management strategy for a take-out specialty sore on the basis of SWOT analysis which requires analysis of internal and external environmental informations. The survey was performed in order to gather the internal and external customer informations for a take-out specialty store. The questionnaires developed were distributed to customers (N=188) and employees (N=23) at 5 take-out specialty store branches from April 25, 2002 to April 29, 2002. The statistical data analysis was completed by SPSS WIN 10.0 for descriptive analysis, factor nalaysis, and Pearson's correlation. IPA(Importance-Performance Analysis) was applied in order to identify the critical management issues which would be explained with the organization's weakness or strength. SWOT analysis was performed through identifying the organizational strength and weakness as internal environment factors and external environmental opportunity and threat as uncontrollable external factors.