• Nuclear Engineering and Technology
• /
• 제54권10호
• /
• pp.3888-3896
• /
• 2022

Nuclear data is the basis of reactor physics analysis. This paper aim at studying the influence of major evaluated nuclear data libraries, CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, and JENDL-4.0u, on the neutronics modelling of CEFR start-up tests. Results show these four libraries have a good performance and consistency in the modelling CEFR start-up tests. The JEFF-3.3 results exhibit only an 8 pcm k_eff difference with the measurement. The difference in criticality is decomposed by nuclide, which shows the large overestimation of CENDL-3.2 is mainly from the cross-section of ⁵²Cr. Except for few cases, the calculation results are within 1σ of measurement uncertainty in control rod worth, sodium void reactivity, temperature reactivity, and subassembly swap reactivity. In the evaluation of axial and radial reaction distribution, there are about 65% of relative errors that are less than 5% and 82% of relative errors that are less than 10%.

• 한국환경과학회지
• /
• 제33권6호
• /
• pp.355-365
• /
• 2024

This study was conducted to investigate the effects of CO₂ supplement on growth and quality in greenhouse lettuce cultivation. When CO₂ was supplied at 1,500 ppm in lettuce cultivation, overall growth parameters such as number of leaves, leaf area, plant length, fresh weight, and dry weight were superior compared to those of the control group. While there was no significant difference in relative growth rate due to CO₂ supplement, an increase in leaf area index was observed with CO₂ usage. Furthermore, although there was no significant difference in the content of water-soluble vitamins such as Vitamin C, B1, B2, B5, and B6 due to CO₂ supplement, the Vitamin B3 content in the CO₂ treatment group was 0.5 mg/kg higher than in the control group. Therefore, the use of CO₂ in lettuce cultivation resulted in increased yield and promoted growth, enabling early harvesting.

• 한국생활과학회지
• /
• 제21권2호
• /
• pp.349-362
• /
• 2012

This paper explores differences demonstrated by changes of consumers' clothing expenditure in Korea and the United States since the mid-1990s. Evidence for this study was extrapolated from annual data provided by the Household Expenditure Survey, which was carried out in Korea between 1996 and 2008, and the Consumer Expenditure Survey, which was carried out in the United States during the same time period. The results include: (1) The proportion of the clothing expenditure decreased during the subject period in both Korea and the United States; (2) The decrease in proportional clothing expenditure was greater in Korea than in the United States; (3) Although the relative prices of clothes decreased greatly during this period in both countries, it was determined that the decrease in clothing prices in the United States was greater when compared to those in Korea; and (4) By using the DID(Difference in difference) model, the author contends that a decrease in clothing purchases contributed to the decrease of prices for clothing in the United States, while in Korea, the decrease in prices for clothing was also impacted by other factors including changes in household expenditures for education and communication.

• 한국의류산업학회지
• /
• 제5권5호
• /
• pp.503-510
• /
• 2003

The purpose this study is to segments apparel market based on difference real-self image and ideal-self image. The objects of the study were to prepare for the establishment of marketing strategy and alternative plan intended to users which are needed in subdivided market, after analyzing according to what the subdivided market is divided into due to the difference real-self image and idea-self image and what difference do they show as a demographic special quality or as a general active special quality in each subdivided market. Factor analysis was performed to determine the leading difference real-self image and ideal-self image, and cluster analysis was employed to identify groups of respondents based on the delineated five image difference factors. Based on the finding, three distinct groups were formed: ideal-self image seeker group, moderators group, real-self image seeker group. And logistic regression was used to assess the relative importance that demographic characteristics play in determining the segmentation. The results of this study show statistically significant differences among the three groups in terms of demographic. Marketing and management implications for effectively targeting the segments are discussed.

• Nutrition Research and Practice
• /
• 제14권6호
• /
• pp.679-690
• /
• 2020

BACKGROUND/OBJECTIVES: Concerns about regional disparities in heathy eating and nutritional status among South Korean adults are increasing. This study aims to identify the magnitude of regional disparities in diet and nutritional status among Korean adults who completed the 2017 Korea National Health and Nutrition Examination Survey (KNHANES). SUBJECTS/METHODS: The participants were a nationally representative sample of Korean adults aged 19 years and older from the 2017 KNHANES (n = 6,126). We employed the svy commands in STATA to accommodate the complex survey design. The relative concentration index (RCI), absolute concentration index (ACI) and index of disparity were used to measure regional nutritional inequalities. RESULTS: Overweight and obese adults were more prevalent among the poor than among the rich in urban areas (RCI = -0.041; P < 0.05), while overweight and obese adults were more prevalent among the rich than among the poor in rural areas of South Korea (RCI = 0.084; P < 0.05). Economic inequality in fruit and vegetable intake ≥ 500 g per day was greater in rural areas than in urban areas in both relative size (RCI = 0.228 vs. 0.091, difference in equality = 0.137; P < 0.05) and absolute size (ACI = 0.055 vs. 0.023, difference in equality = 0.032; P < 0.05). CONCLUSIONS: This study provides useful information identifying opposite directions in the relative concentration curves between urban and rural areas. Adult overweight/obesity was more prevalent among the poor in urban areas, while adult overweight/obesity was more prevalent among the rich in rural areas. Public health nutrition systems should be implemented to identify nutritional inequalities that should be targeted across regions in South Korea.

• 한국항해항만학회지
• /
• 제36권6호
• /
• pp.429-435
• /
• 2012

위성항법시스템의 기술발전이 지속적으로 진행되고 있지만 여전히 신호차폐가 빈번히 발생하는 지역에서는 측위정확도 확보에 어려움을 겪고 있다. 이 연구에서는 통합 GPS/GLONASS 이중차분 상대측위 알고리즘을 구현하고 신호차폐 환경의 시뮬레이션을 수행해 그 성능을 검증하였다. 동쪽, 서쪽, 남쪽 방향으로 고층건물에 의해 신호차폐가 발생하는 환경을 시뮬레이션 하고 시뮬레이션 상황에 따른 GPS와 GPS/GLONASS의 정확도 평가를 수행하였다. 그 결과, 신호차폐 시뮬레이션 환경에서는 GPS/GLONASS가 GPS에 비해 최소 0.3m에서 최대 13m이상의 수평정확도가 향상되었다.

• 한국의학물리학회지:의학물리
• /
• 제28권1호
• /
• pp.33-38
• /
• 2017

Creating individualized build-up material for superficial photon beam radiation therapy at irregular surface is complex with rice or commonly used flat shape bolus. In this study, we implemented a workflow using 3D printed patient specific bolus and describe our clinical experience. To provide better fitted build-up to irregular surface, the 3D printing technique was used. The PolyLactic Acid (PLA) which processed with nontoxic plant component was used for 3D printer filament material for clinical usage. The 3D printed bolus was designed using virtual bolus structure delineated on patient CT images. Dose distributions were generated from treatment plan for bolus assigned uniform relative electron density and bolus using relative electron density from CT image and compared to evaluate the inhomogeneity effect of bolus material. Pretreatment QA is performed to verify the relative electron density applied to bolus structure by gamma analysis. As an in-vivo dosimetry, Optically Stimulated Luminescent Dosimeters (OSLD) are used to measure the skin dose. The plan comparison result shows that discrepancies between the virtual bolus plan and printed bolus plan are negligible. (0.3% maximum dose difference and 0.2% mean dose difference). The dose distribution is evaluated with gamma method (2%, 2 mm) at the center of GTV and the passing rate was 99.6%. The OSLD measurement shows 0.3% to 2.1% higher than expected dose at patient treatment lesion. In this study, we treated Mycosis fungoides patient with patient specific bolus using 3D printing technique. The accuracy of treatment plan was verified by pretreatment QA and in-vivo dosimetry. The QA results and 4 month follow up result shows the radiation treatment using 3D printing bolus is feasible to treat irregular patient skin.

• 대한원격탐사학회지
• /
• 제26권2호
• /
• pp.87-98
• /
• 2010

한반도 전역과 같은 상대적으로 넓은 지역의 정확한 분류를 위해서는 단일 영상 분류 후 영상정합 방식보다는 영상 정합 후 분류방법이 보다 정확하다. 또한 다중시기 정보는 분류에 매우 유용하게 사용될 수 있다. 본 연구에서는 한반도 전역을 대상으로 최적의 Landsat ETM+ 영상정합 방식을 제시하였다. 한반도 전역에 대해 2000년부터 2001년까지 획득된 총 65개의 Landsat ETM+영상을 이용하여 낙엽기, 이앙기, 개엽기 각각 정합 영상을 제작하였다. 이때 보다 정확한 영상정합을 위해 히스토그램 매칭, 중앙영상을 기준으로 한 1차 회귀식적용방법, Landsat 촬영 패스별로 적용한 1차 회귀식 적용방법, 총 세 가지 상대복사보정 방법을 적용하였다. 적용 결과, 패스별 상대복사보정한 결과가 그 보정 효과가 크면서, 높은 분류 정확도를 나타냈다. 또한 시기별 정합영상을 살펴보면, 개엽기의 정합영상이 타시기에 비해 상대적으로 인접한 영상 간 지표물의 변이가 다양하게 나타나는 것을 볼 수 있었다.

• 한국지반환경공학회 논문집
• /
• 제23권5호
• /
• pp.5-13
• /
• 2022

본 연구에서는 국내 지진모의시험 수행 시 모래지반의 모사를 위해 국내에서 널리 이용되는 지반재료인 인공규사를 대상으로 상대밀도 차이에 따른 진동삼축시험을 수행하여 인공규사의 동적특성 및 액상화 저항특성을 실험적으로 분석하였다. 상대밀도 조건을 40%, 60%, 80%로 달리한 시험결과를 통해 상대밀도에 따른 액상화 저항특성을 확인하였으며, 액상화 진동저항응력비(Cyclic resistance stress ratio, CRR) 산정 곡선을 도시하였다. 또한, 액상화 진동저항응력비(CRR) 산정곡선의 타당성을 검토하기 위해 실내진동삼축시험에 사용된 규사로 이루어진 인공지반을 조성한 후, 간편예측법과 상세예측법을 통한 액상화 평가를 수행하여 각각의 안전율을 비교·검토하였다. 최종적으로, 상대밀도를 달리한 실험을 통해 인공규사의 동적물성을 파악하여 결과를 도출하였으며, 이 결과를 물성치로 적용한 상대밀도 40% 간편예측법은 안전율이 1로 안전한 지반으로 도출된 반면 상세예측법은 0.05작은 값으로 결과가 도출되었다.

• 재무관리연구
• /
• 제23권2호
• /
• pp.85-107
• /
• 2006

이 논문에서는 새로운 뉴스에 대해 선물시장이 현물시장보다 더 민감하게 반응하는지와 더 큰 가격변동폭을 보이는지를 검증한다. 뉴스에 대한 민감도는, 선물가격의 일간변동을 이론가격 변동에 관해 회귀시킨 식의 회귀계수에 의해 측정한다. 그리고 가격변동폭은 선물가격과 이론가격의 평균범위차이($\overline{RD}$), 평균고가차이($\overline{HD}$) 및 평균저가차이($\overline{LD}$)라는 세 가지 척도를 사용하여 측정한다. 이 논문에서 사용한 자료는 코스피200 지수선물시장의 개설 초기인 1996년 7월부터 최근의 2005년 12월말까지 최근월물과 차근원물의 선물가격과 이론가격이다. 민감도의 차이를 나타내는 $\hat{\beta}$는 1과 크게 유의한 차이를 보이지 않으므로 뉴스에 대한 두 시장의 민감도는 대체로 큰 차이가 있는 것으로 보이지 않는다. 그러나 최근기간(2002년 11월${\sim}$2005년 12월)에는 최근월물 및 차근월물 모두 1보다 큰 값을 보이고 있어 선물시장이 더 민감하게 반응하고 있다. 또 최근기간에 최근월물의 가격이 좋은 뉴스에 대해 현물시장보다 더 민감하게 반응하였다. 전체기간 및 하위기간의 ($\overline{RD}$)는 대체로 0과 유의한 차이를 갖지 않는다. 그러나 최근월물의 평균고가차이($\overline{HD}$)는 전체기간과 하위기간 모두에서 뚜렷하게 유의한 양의 값을 보이고 있다. 이것은 최근월물 선물가격의 좋은 뉴스에 대한 가격변동폭이 현물가격보다 더 크다는 것을 의미한다.