• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.165-165
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• 2012

육상, 해양, 항공 등의 응용분야에 위성항법보강시스템의 활용을 위해서는 시스템의 정확성, 무결성, 연속성, 가용성 요구 조건을 만족하도록 설계되어야 하며, 무결성 요구 조건을 만족시키기 위하여 측위 오차 및 위협 요인들을 지상국에서 감시해야한다. 특히, 전리층 변화는 지역적으로 경향 및 세기가 달라 전리층 폭풍 발생 시 지상국과 이동체에서 받은 위성항법 신호에 포함된 전리층 지연 오차의 편차가 심하여 위성항법 사용자의 무결성, 즉 안정성이 위협을 받는 상황이 발생할 수 있으므로, 해당지역의 전리층 변화에 대한 사전 정보를 통해 지역별로 적합한 위협 모델을 구성하여 전리층 활동 감시가 필요하다. 전리층 기울기는 전리층 지연값 분포의 불균일 여부를 정량화한 값으로, 전리층 폭풍 발생시 기울기가 급증하여 전리층 폭풍 감지를 위한 지표로 활용될 수 있다. 이 연구에서는 육상 교통 위성항법보강시스템의 무결성 감시에 전리층 변화 기능을 적용하기 위한 기본 연구로 IGS에서 제공하는 전리층 보정정보를 이용하여 한반도 상공에 대한 전리층 기울기 분포 및 변화 경향을 파악하고, 이러한 분석 결과를 전리층 기울기에 대한 보정정보 오차범위 설정이나 전리층 폭풍 발생 판단에 필요한 임계값 설정 등에 적용하고자 한다.

• Journal of Korean Dental Hygiene Science
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• v.7 no.1
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• pp.29-37
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• 2024

Background: This study investigatedthe factors influencing the degree of education in the Department of Dental Hygiene at K University on the degree of education required for a convergence major related to the medical device industry. Methods: For 5 days from December 5, 2023, 257 students of the Department of Dental Hygiene at a university in Wonju Citywere surveyed, and an online survey was conducted. General characteristics, school satisfaction, satisfaction with majors, perceptions of multi-majors in universities, and the degree of demand for a convergence major related to the medical device industry were examined. Since normality was not satisfied, non-parametric analysis was performed. To confirm the differences in convergence major related to medical device industry education needs according to general characteristics, the Mann-Whitney U test and Kruskal-Wallis test were performed. Post-hoc analysis was performed, and the median, minimum, and maximum values were presented. Multiple regression analysis was performed to confirm the effect on the demand for a convergence major related to the medical device industry, and the statistical significance probability was set at 0.05. Results: As a result of examining the factors affecting the demand for a convergence major related to the medical device industry, it was found that the more experience one has in completing a double major in college (p<0.05) and the higher the degree of satisfaction with the major (p<0.05), the statistically significant need for an interdisciplinary major was higher(p<0.05).

• Food Science and Preservation
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• v.19 no.5
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• pp.774-782
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• 2012

Baechu kimchi without cuttlefish (control), baechu kimchi with cuttlefish (CK), cuttlefish baechu kimchi with yogurt (CK+Y), and cuttlefish baechu kimchi with vitamin C (CK+VC) were prepared, and the fermentation characteristics of the prepared kimchi samples were investigated during 28 days of fermentation at $4^{\circ}C$. The levels of moisture, crude lipid, and crude ash did not differ much among the samples, but the crude protein levels of CK, CK+Y, and CK+VC were greater than that of the control. The pH values of CK+Y and CK+VC slowly decreased compared with those of the control and CK during fermentation. The acidity increased sharply until 21 days then gradually increased thereafter. The total microbial counts achieved maximum levels at 21 days, and the kimchi to which yogurt and vitamin C were added showed values lower than that of the control. The number of Leuconostoc sp. in CK+Y and CK+VC was higher than that in the control. In our sensory evaluations, cuttlefish kimchi with yogurt or vitamin C scored highest in terms of texture, sour taste, ripened taste, and overall acceptability.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.73-84
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• 2006

The objective of this study was to analyze long-term temporal trends of water chemistry and spatial heterogeneity for 10 sampling sites of the Yeongsan River watershed using water quality dataset during 1995 to 2004 (obtained from the Ministry of Environment, Korea). The water quality, based on multi-parameters of biological oxygen demand (BOD), chemical oxygen demand (COD), conductivity, dissolved oxygen (Do), total phosphorus (TP), total nitrogen (TN) and total suspended solids (TSS), largely varied depending on the sampling sites, seasons and years. Largest seasonal variabilities in most parameters occurred during the two months of July to August and these were closely associated with large spate of summmer monsoon rain. Conductivity, used as a key indicator for a ionic dilution during rainy season, and nutrients of TN and TP had an inverse function of precipitation (absolute r values> 0.32, P< 0.01, n= 119), whereas BOD and COD had no significant relations(P> 0.05, n= 119) with rainfall. Minimum values in conductivity, TN, and TP were observed during the summer monsoon, indicating an ionic and nutrient dilution of river water by the rainwater. In contrast, major inputs of total suspended solids (TSS) occurred during the period of summer monsoon. BOD values varied with seasons and the values was closely associated (r=0.592: P< 0.01) with COD, while variations of TN were had high correlations (r=0.529 : P< 0.01) with TP. Seasonal fluctuations of DO showed that maximum values were in the cold winter season and minimum values were in the summer seasons, indicating an inverse relation with water temperature. The spatial trend analyses of TP, TN, BOD, COD and TSS, except for conductivity, showed that the values were greater in the mid-river reach than in the headwater and down-river reaches. Conductivity was greater in the down-river sites than any other sites. Overall data of BOD, COD, and nutrients (TN, TP) showed that water quality was worst in the Site 4, compared to those of others sites. This was due to continuous effluents from the wastewater treatment plants within the urban area of Gwangju city. Based on the overall dataset, efficient water quality management is required in the urban area for better water quality.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.475-481
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• 2013

The control system of a direct drive servo valve is a nonlinear system, and the flow force effect on the spool motion is significant and dependent on the load pressure. To satisfy the control system design requirements, the optimal parameters of the lead-lag controller and the derivative feedback controller are searched for using a genetic algorithm and a complex constrained direct search type method. The obtained controller parameters successfully perform their role to satisfy the control system design requirements.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.6-10
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• 2011

This article deals with a problem of setting reliability targets of the railroad systems where the punctuality target is given to the operator and a penalty is imposed for the year when the target is not met. The operator should set the reliability targets of the railroad system and sub-systems because the reliability affects the expected number of years when the penalty is imposed. This paper presents a procedure for setting the service reliability target and equations to calculate the expected number of years when the penalty is imposed and the probability that the operator should pay the penalty per year according to the mean kilometer between service failures of the railroad system and sub-systems.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.317-326
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• 2003

In order to improve our knowledge of the characteristics of organic compounds in coastal waters, water samples were collected from the Incheon coastal region, the Hyungsan River in Youngil Bay and the Busan coastal region. Also, mooring was carried out near the Kanghwa Island and Seo Island. In this study, the relationship between the total organic carbon (TOC) and salinity, chemical oxygen demand (COD) and salinity were evaluated and determined. Riverine end-member of TOC into the Korean coastal area and its COD estimated from these relationships were 5.32 mg C/l and 8.87 mg O$_2$/l, respectively. The oxidation efficiency of COD to TOC estimated using the high-temperature catalytic oxidation method was about 47％. The linear relationship between TOC and COD was derived as COD (mg O$_2$/l)=0.61${\times}$TOC (mg C/l) -0.03, (R$^2$=0.66). Therefore, it is possible to estimate total organic carbon using this equation from previously reported chemical oxygen demand.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2030-2037
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• 2012

The purpose of this research is to suggest a model or method of needs analysis for designing syllabuses. As the learner-centered approach in teaching and learning methods becomes general, the learners' needs or wants should be reflected on the syllabus design. However, standardized scores in the previous research have disadvantages to be distorted in data interpretations because the difference between the maximum value and minimum value is so big compared to the Likert 5 scales. To solve this disadvantage, the Max-Min method is used in the needs analysis for the syllabus design. So, the differences are presented. Needs analyses need to be selected variously according to situations. Thus, further researches are needed to develop several new methods as well as the Max-Min method or the standardized score method for the whole needs analyses.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.477-480
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• 2001

무선 정보 환경의 변화에 따라 다양한 정보에 대한 풍족함이 요구되면서 양질의 정보를 정확하고 빠르게 선별하여 획득하는 기술이 점점 중요하게 되었으며, 이러한 페러다임의 요구에 Mobile Agent는 중요한 연구가 된다. 본 논문에서는 Mobile Agent가 가져야 할 보안적 요구사항 중 신뢰할 수 있는 Proxy Server를 이용한 인증을 통해 Sever와 Mobile Agent간의 안전한 통신 방법을 제시하며, Server나 Mobile Agent의 부정이 발견되었을 경우 DSS(Digital Signature Standard) 방식의 서명값을 이용하여 이를 증명함으로써 보다 안전하고 효율적인 상호인증 방식을 제안하였다.

• The Optical Journal
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• s.96
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• pp.49-54
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• 2005

프로젝션 TV, 비디오 카메라나 CD 등과 같은 전자 광학((Electro-optics) 제품 시장이 확대되고 있다. 이들 제품의 광학 부품을 소형경량화·고성능화·저가격화 하기 위해 각 제조업체에서 독자적인 비구면 가공 기술을 개발하고 있으며, 종전의 유리 렌즈에서 좀더 가벼운 플라스틱 렌즈로 이동하고 있다. 이 광학 부품들의 요구 정밀도는 형상 정밀도, 면 거칠기 모두 요구값이 높아지고 있으며 초정밀 비구면 경면 절삭 기술이 이용되고 있다. 본 고에서는 프로젝션 TV 및 비디오 카메라의 비구면 플라스틱용 금형을 대상으로 무전해 니켈 도금막의 초정밀 경면 절삭 기술에 대해 소개한다.