• Journal of the Optical Society of Korea
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• v.16 no.3
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• pp.299-304
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• 2012

A high angular tolerance spectral filter was realized incorporating an etalon, which consists of a $TiO_2$ cavity sandwiched between a pair of Ag/Ge mirrors. The effective angle was substantially extended thanks to the cavity's high refractive index. The device was created by embedding a 313-nm thick $TiO_2$ film in 16-nm thick Ag/Ge films through sputtering, with the Ge layer alleviating the roughness and adhesion of the Ag layer. For normal incidence, the observed center wavelength and transmission were ~900 nm and ~60%, respectively; throughout the range of $50^{\circ}$, the relative wavelength shift and transmission variation amounted to only ~0.06 and ~4%, respectively.

• The Korean Journal of Ecology
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• v.8 no.4
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• pp.205-214
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• 1985

At the Changnyeung natural bod, the flood in the freshwater wetland and the adaptation of the insect at this area were investigated by the species diversity index and the cluster analysis. Most dominant species was Diplonychus esakii collected at the site of the water edge and its dominance index was 0.797. This area had lower species diversity indices with the value of 0.340 to 1.712 than that of the grassland and water stream. The number of the species in this area was not rich. Some ground beetles inhabited at the flooded or wet area were important species for the pair group between the sites by the cluster analysis. The composition of the insect species at this natural wetland affected by the irregular flood was very simple and specific.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.344-356
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• 2001

This paper deals with the subsequence searching problem under time-warping in sequence databases. Our work is motivated by the observation that subsequence searches slow down quadratically as the average length of data sequences increases. To resolve this problem, the Segment-Based Approach for Subsequence Searches (SBSS) is proposed. The SBASS divides data and query sequences into a series of segments, and retrieves all data subsequences that satisfy the two conditions: (1) the number of segments is the same as the number of segments in a query sequence, and (2) the distance of every segment pair is less than or equal to a tolerance. Our segmentation scheme allows segments to have different lengths; thus we employ the time warping distance as a similarity measure for each segment pair. For efficient retrieval of similar subsequences, we extract feature vectors from all data segments exploiting their monotonically changing properties, and build a spatial index using feature vectors. Using this index, queries are processed with the four steps: (1) R-tree filtering, (2) feature filtering, (3) successor filtering, and (4) post-processing. The effectiveness of our approach is verified through extensive experiments.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.2
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• pp.123-130
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• 1985

This paper was conducted for the purpose of evaluating the accuracy of the observed time difference in Loran-C when the ground wave propagated on the surface included both land sea. The time difference of X and Y station in North East Pacific Chain GRI 5970 was measured at 25 points in Cheju areas. The results obtained are as follows: (1) The errors of time difference for M-X pair are increased when the Loran-C wave propagates above 500m heights of Hanla mountain on propagation path between the observed point and master or X, Y slave station. (2) The errors of time difference for M-X pair are able to decrease by way of correction for the propagation velocity and the geodetic datum, but errors of the time difference for M-Y pair very irregularly because irregular terrain include in propagation path from X station and propagation path from Y station is twice longer than X station. (3) It is confirmed that accuracy of Loran-C fix can elevate by the way of all correction for a geodetic datum transformation, the propagation velocity with refractive index of radio wave and the propagation velocity over land.

• The KIPS Transactions:PartB
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• v.15B no.4
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• pp.355-364
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• 2008

In general, we can use an inverted index for retrieving element lists from structured documents. An inverted index can retrieve a list of elements that have the same tag name. In this approach, however, the cost of query processing is linear to the length of a path query because all the structural relationships (parent-child and ancestor-descendant) should be resolved by structural join operations. In this paper, we propose an inverted index technique and a novel structural join technique for accelerating XML path query evaluation. Our inverted index can retrieve element lists for path segments in a parent-child relationship. Our structural join technique can handle lists of element pairs while the existing techniques handle lists of elements. We show through experiments that these two proposed techniques are integrated to accelerate evaluation of XML path queries.

• Journal of Korea Port Economic Association
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• v.35 no.4
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• pp.107-120
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• 2019

Crude oil is a resource that is being used as a raw material in major industries, representing the price of the raw material market. It is also an important element that affects the shipping market in terms of fuel costs for freight vessels. As a result, crude oil and freight rates are closely related. Therefore, from January 2009 to June 2019, this study analyzed the dependency structure between oil price (WTI) and freight rates (BDI, BCI, BPI, BSI, and BHI) using daily data. The main results are summarized as follows. First, according to the copula results, survival Gumbel copula in WTI-BDI, Clayton copula in WTI-BCI, Survival Joe copula in WTI-BPI, Joe copula in WTI-BSI, and survival Gumbel copula in WTI-BHI were selected as the best-fitted model. Second, looking at Kendall's tau correlation, there is a positive correlation between BDI and oil price. Furthermore, freight rate index (BCI, BPI, BSI) and oil price show positive dependencies. In particular, the strongest dependence was found in BCI and oil price returns. However, BHI and oil price show a negative dependency. Third, looking at the tail-dependency structure, a pair between oil price and BDI, BCI showed a lower tail-dependency. The pair between oil price and BSI showed the upper tail-dependency.

• The Journal of Korean Medicine
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• v.20 no.1 s.37
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• pp.60-65
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• 1999

We have conducted a study of the interobserver reliabilities of Modified Barthel Index and Motor Assessment Scale with 30 patients hospitalized with strokes in the department of circulatory internal medicine, Sang Ji University Oriental Hospital. The observations were performed by two staff and residents in the circulatory internal medicine department. Raters were assigned in random pairs to individual patients. Evaluations were performed independently by the two observers. In order to minimize the impact of fluctuations in the patients' clinical status, the second set of observations immediately followed the first. Each patient was used for only one pair of evaluations. The results were as follows. 1. Mean kappa value of 13 items in Modified Barthel Index(MBD was 0.742, which indicated excellent interobserver reliability. The kappa values indicated almost $perfect({\kappa}:\;0.81-1.00)$ for 4, substantial for $9({\kappa}:\;0.61-0.80)$, and moderate for $2({\kappa}:\;0.41-0.60)$ of 13 items. All items. except Grooming item, showed statistically significant interobserver agreement(p<0.01) 2. Mean kappa value of 8 items. except General tonus, in Motor Assessment Scale(MAS) was 0.823, which indicated excellent interobserver reliability. and this value of Motor Assessment Scale was more high than MBI' s value. 0.81. The kappa values indicated almost perfect for 5, substantial for 3 of 8 items. All items showed statistically significant interobserver agreement(P<0.01).

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.143-149
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• 2007

To certify predictability for the times of phenological stages from cumulative air temperature in springtime, the first times of budding, leafing, flower budding, flowering and deflowering for 14 woody plants were monitored and air temperature was measured from 2005 to 2006 at Namsan. Year day index (YDI) and Nuttonson's Index (Tn) were calculated from daily mean air temperature. Of the 14 woody species, mean coefficient of variation was 0.04 in Robinia pseudo-acacia and 0.09 in Alnus hirsuta. However, mean coefficient of variation was 0.30 in Forsythia koreana and Stephanandra incisa and 0.32 in Zanthoxylum schinifolium. Therefore, the times of each phenological stage could be predicted in the former two species but not in latter three species by two indices. Of the five phenological stages, mean coefficient of variation was the smallest at deflowering time and the largest at budding time. In five phenological stages, mean coefficient of variation of YDI was in the range of $0.11{\sim}0.21$ but that of Tn was in the range of $0.15{\sim}0.26$. Therefore, the former was a better index than the latter. Of the species-phenological stage pair, coefficient of variation of YDI was 0.01 in Acer pseudo-sieboldianum - flower budding and below 0.05 in 11 pairs, whereas the YDIs over 0.40 were 4 pairs comprising of Prunus leveilleana - budding (0.51). Coefficient of variation of Tn was 0.01 in A. hirsuta - budding and below 0.05 in 8 pairs. The Tns over 0.40 were 5 pairs comprising of F. koreana - flower budding (0.66).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.469-482
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• 2013

This study identified problems of the existing ecosystem-based fisheries assessment approach, and suggested new methods for scoring risk and for the estimation of fishery risk index. First, risk scores of zero to two for target and limit reference points for each indicator were replaced by those of zero to three, and the risk scores were calculated from new formulae which were developed in this study. Second, a new method for estimating fishery risk index (FRI) was developed in this study, considering the level of indicators. New method was applied to the Korean large purse seine fishery, large pair trawl fishery and drag net fishery. More precise and detailed risk scores were obtained from the new method, which can explain the risks by the wider range of both risk levels for 'better than target' and 'beyond limit'. The new method for estimating FRI could avoid the basic problem related with duplicated computations of fishery-level indicators, which improved the estimated FRI to be more accurate. Also, a method for estimating variance of FRI using the bootstrap was proposed in this study.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.3
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• pp.26-34
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• 2004

It is expected that the different techniques of stream restoration could be caused the different conditions of the stream ecosystem. The study was to investigate and compare plants and vegetation clusters of appearing plant species in the upper and lower section of the Seo-Ho stream, It was classified and listed all of the plants appeared in the upper and lower section of the stream, It was used the belt-transect method and Unweighted pair group method using arithmetic algorithm in order to examine and analyzed discover the vegetation clusters, In the result, 28 families and 114 species appeared in the upper section, In the other side, 26 families and 93 species appeared in the lower section of the steam. The naturalized index of the upper section was 21%, and that of the lower section was 27%. In addition, the upper section has more various geographical features than lower section of the stream. So that, consequently the study shows that the different techniques of stream restoration could be caused the different growth of the stream ecosystem.