• 한국해양공학회지
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• 제33권3호
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• pp.252-258
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• 2019

In this paper, the time history of the surface elevation measured at the Draupner platform in the North Sea in 1995 is used to examine the statistical characteristics of the wave data. The wave statistics for 48 surface measurements, which contain three freak wave occurrences, are summarized. The quartiles, boxplots, correlations, and pair plots of 15 variables, along with the abnormality index, are presented. The kurtosis and skewness of the surface elevation are two variables that are highly correlated with the abnormality index, which defines freak waves. Principal coordinate analysis showed that the direction of the changes in the abnormality index agreed with the changes in the kurtosis and skewness. In addition, various wave heights, except the maximum wave height, showed a similar direction for the height changes, and various wave periods showed a similar direction for the period changes. Based on the correlations and PCA analysis, the kurtosis and skewness of the surface profiles are the two most important variables to predict the abnormality index.

• 무역학회지
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• 제47권4호
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• pp.293-309
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• 2022

The purpose of this paper is to analyze the import and export volume of Jeollabuk-do to establish a plan to activiation Saemangeum New Port. To this end, this study utilized the HHI(Herfindahl-Hirschman Index), LQ(Location Quotient) analysis using the annual data set from the Korea Trade Statistics Promotion Institution between 2015 to 2020. As a result, it has been confirmed that the degree of export volume concentration (HHI (Herfindahl-Hirschman Index)) in Jeollabuk-do has been increasing over the past 5 years. According to results of LQ(Location Quotient) analysis, Brazil had the highest index in the case of exporting countries, and Meat, edible meat offal (HS 2) had the highest index in the case of export items. This paper is meaningful in analyzing the export structure using import and export volumes and proposing a plan to improve the competitiveness of Saemangeum New Port.

• 한국지리정보학회지
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• 제2권3호
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• pp.16-22
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• 1999

생물서식지의 다양한 공간구조는 생물의 종 다양성과 밀접한 관계를 가지고 있다. 인구의 증가, 농업의 발달, 그리고 도시의 발전은 최근에 다양한 경관의 변화를 가져왔다. 이러한 경관의 변화는 생태적 구성인자의 서식지 감소와 파편화(fragmentation)를 초래하였다. 본 연구에서는 Landsat TM을 이용하여 식생지수를 산출하고 이를 식생 패치의 경계길이 대 면적 (perimeter : area, P/A ratio), Shape Index(SI), 프렉탈 디멘죤(D)에 의해 추출한 파편화지수를 분석하였다. NDVI에 의한 경관파편화의 분석은 0.5~1의 구간 값을 이용하는 것이 가장 파편화를 용이하게 구분할 수 있음을 알 수 있었다. 또한, 서울 경기지역의 식생 파편화는 프렉탈 디멘죤에 의해 구분할 때 가장 효과적으로 식생 패치의 파편화를 구분해 낼 수 있음을 알 수 있었다. 향후 동일지역에 대한 식생 패치의 시계열적인 분석과 다양한 토지이용에 대한 식생 파편화의 분석을 비교 연구하여 식생 보전과 생물다양성의 전략을 제시할 수 있을 것이다.

• 펄프종이기술
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• 제44권4호
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• pp.43-50
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• 2012

The crystallinity index is an important characteristic of cellulose. The crystallinity value is different depending on the adopted instrument. In this study, we determined a crystallinity index of cotton and wood celluloses using wide-angle X-ray scattering (WAXS), powder X-ray diffractometer (PXRD), and cross polarization/magic angle spinning solid-state $^{13}C$ nuclear magnetic resonance spectroscopy (CP/MAS solid-state $^{13}C$ NMR). The specimen was prepared in forms of powder, sheet and pallet. With the comparison of the obtained crystallinity indices of the cellulose, the effects of the analysis instrument, the sample preparation and analysis method were investigated. Among three instruments, the crystallinity indices by PXRD and NMR had a good relationship and reproducibility, and WAXS gave the crystallinity index with poor reproducibility. In the case of analysis methods of crystallinity indices, the Segal method showed higher value than that of the Ruland-Vonk method. We expect that this study would be applicable to evaluate the crystallinity index of various cellulose materials with accuracy and reproducibility.

• 대한전자공학회논문지
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• 제23권4호
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• pp.522-528
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• 1986

Based on the modified effective index method, analysis of dielectric rectangular waveguides and directional couplers are presented. Aside from the effective index concept of channel region, the equivalent index concept of cladding region is proposed. The error problem of eigenvalues, which has been experienced when the effective index method is used, is improved. Our approxiamtions give similar accuracy when compared with the results of other regorous approxiamtion techiniques. The advantage of the modified effective index methods is utilized by replacing the directional coupler with the equivalent slab guides, and the coupling constant is calculated by the coupled mode theory. The effectiveness of the equivalent index concept is positively confirmed.

• 한국물환경학회지
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• 제39권4호
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• pp.261-268
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• 2023

The benthic macroinvertebrates index (BMI) was developed based on the 5-day biochemical oxygen demand (BOD₅), which is the amount of biodegradable organic matter in stream water. However, benthic macroinvertebrates mainly live in the streambed substrate and are affected by the interaction of water quality and substrate. This study was conducted to examine the interactive relationship between water quality items (BOD₅, total phosphorus (TP), total suspended solids (TSS)) and substrate with BMI by performing statistical analyses (four-way analysis of variance, Pearson's correlation analysis, partial correlation analysis and multiple regression analysis). The data used in the analyses were collected from 19,915 sampling units at 1,937 sites in South Korea from 2010 to 2020. The interaction effect between BOD₅ and substrate types was confirmed through a four-way analysis of variance. Partial correlation analysis and multiple regression analysis estimated the degree of influence on the change in BMI value in the order of mean grain size of the substrate as (𝜱_m) > BOD₅ > TP > TSS. BMI can be regarded as an index that evaluates the comprehensive effects of water quality and streambed status, although it is an index that was developed based on the amount of biodegradable organic matter in a water column.

• 한국IT서비스학회지
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• 제12권4호
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• pp.423-434
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• 2013

Since acquiring intelligence about political situations around the Korea Peninsular in a direct manner is nearly impossible, it is inevitable for the individuals or companies to rely on open and indirect data such as newspapers. However, since the contents in the newspapers are substantially unstructured and very large, conventional content analysis is time-consuming and hence very costly. Hence, this paper aims to propose a sentimental analysis method which computes daily 'peace index' from unstructured data in the newspapers. From the content analysis, words and phrases which represent the sentiment of a nation are carefully identified. To show the feasibility of the idea proposed in this paper, a prototype system with vocabulary repository about political situations was developed for estimating peace index automatically.

• Geomechanics and Engineering
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• 제12권2호
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• pp.313-326
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• 2017

Based on the reliability theory and limit analysis method, the roof stability of a shallow tunnel is investigated under the condition of surface settlement. Nonlinear Hoek-Brown failure criterion is adopted in the present analysis. With the consideration of surface settlement, the internal energy and external work are calculated. Equating the rate of energy dissipation to the external rate of work, the expression of support pressure is derived. With the help of variational approach, a performance function is proposed to reliability analysis. Improved response surface method is used to calculate the Hasofer-Lind reliability index and the failure probability. In order to assess the validity of the present results, Monte-Carlo simulation is performed to examine the correctness. Sensitivity analysis is used to estimate the influence of different variables on reliability index. Among random variables, the unit weight significantly affects the reliability index. It is found that the greater coefficient of variation of variables lead to the higher failure probability. On the basis of the discussions, the reliability-based design is achieved to calculate the required tunnel support pressure under different situations when the target reliability index is obtained.

• 산업경영시스템학회지
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• 제32권4호
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• pp.79-86
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• 2009

The purpose of this paper is to analyze the 24 mail center's efficiency and productivity changes from first quarter to fourth quarter of 2008 using window analysis and Malmquist productivity index. Row views of window analysis results make it possible to determine trends and/or observed behavior with the same data set, and column views to examine the stability of results across different data sets. Malmquist productivity indexes greater than unity translate into improvements in productivity, and less than unity mean deterioration in performance over time. The results of this study suggest that DEA models under dynamic situations such as window analysis and Malmquist productivity index enable us to comprehend the efficiency and productivity changes over time and to show the direction of improvements.

• 대한한방부인과학회지
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• 제21권4호
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• pp.169-182
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• 2008

Purpose: The purpose of this study is to find out the relations between the index of obesity by body composition analysis (EMI. %BF and WHR) and results of other oriental health examinations (QSCC II, HRV and APG) on some women. Methods: 114 women who were tested by oriental health examination between May 2006 and August 2008 were studied. Results: As a result of the study on the relations between the index of obesity by body composition analysis and sasang constitution, it was found that each of them had significant differences among themselves and Taeumin had the highest significance than other sasang constitution. As a result of the study on the relations between the index of obesity by body composition analysis and HRV, it was discovered that there was no significant relationship between BMI and WHR and HRV. However, %BF had negative correlations with autonomic activity, stress resistance and stress index. As a result of the study on the relations between the index of obesity by body composition analysis and APG, it was found that they had positive correlations with each other. Conclusion: In conclusion, there are significant relations between the index of obesity by body composition analysis and results of other oriental health examinations.