• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.2
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• pp.28-37
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• 2008

In this study, we perform land surface monitoring of NDVI (Normalized Difference Vegetation Index) variation by using remote sensing data during 1999-2005 over North Korea, which can't easily access to measure directly land surface characteristics due to one of the world's most closed societies. North Korea forest region has most abundant forest vegetation - so called Lungs of Korea in the Korea peninsula. NDVI represents vegetation activity used in many similar studies. In this study, we detect vegetation variation and analysis factors of the change over North Korea. By using variation of NDVI, we can infer that effect of drought over North Korea, and reduced vegetation indices by typhoon in North Korea. Land surface type except barren ground with decreased NDVI value is considered as when North Korea region was suffering from drought and typhoon effects, which show lower than mean of 7-year NDVI value. Especially, in recently, the food production of North Korea with political and economical issues can be inferred indirectly these trends by using estimated output data from this study.

• Journal of Preventive Medicine and Public Health
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• v.26 no.3 s.43
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• pp.430-441
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• 1993

The objectives of this study are two-fold : to identify geographic variations in the rate of tonsillectomy and adenoidectomy (T&A) and appendectomy and analyze the socioeconomic variables and health resources which affect geographic variation in the rate. The nationwide three month's cases of the two surgical procedures in 1991 are obtained from the record of the National Federation of Medical Insurance. The analysis shows two to ten-fold variations in the regional rates for the performance of two common procedures such as T&A and appendectomy. T&A shows a bigger regional variations than appendectomy. As a result of multiple regression, the factor of bed supply has been found significant for the dependent variable of the rate of T&A. The finding of large variations in the rate of surgical procedures throughout the country would have important implications for allocating scarce resources and managing quality of care. Further analysis is needed for the elaboration of the above implications.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.533-534
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• 2000

In general, intertidal gastropods display a considerable amount of intraspecific shell variation (De Wolf et al., 1998). Particularly, thaisid species, including Thais clavigera(=T.c.), have been shown a variety of shell variation in the world ocean (e.g. T, emerginata in Kitching, 1976). Nomura (1926) noted local variation of shell morphology based on five Japanese populations. Ahe (1985) classified Japanese T.c. into two forms (Form-C ＆. -P). In the Korean waters, a strong variation in nodule shape of T.c, shell has also been noted by Choe ＆ Park (1997). Taxonomy of T.c. is controversial so far. (omitted)

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.452-454
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• 2006

• Journal of the Korean Association of Geographic Information Studies
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• v.4 no.3
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• pp.51-60
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• 2001

The travel behavior can be analysed microscopically using GPS because the travel characteristics can be found out by travelling two test cars loaded with GPS equipments. The speed difference and spacing variation between the lead vehicle and the following's in uninterrupted flow are the important variables related to capacity and safety. This study analysed these with data obtained by travelling the 4th Line and 28th Line of the national road. The variation width in speed difference in the run time is below 3.0%. But, related to the speed difference in the situation of acceleration and deceleration the difference after 4second is bigger than that just after the start. The spacing variation is similar to this. The spacing just before deceleration concerning safety was analysed. When the theoretical values by the modeling method and observed values were compared, the observed values were analysed 12.52% shorter than the other in average.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.139-150
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• 2003

There was a close relationship between spatio-temporal distribution of Cochlodinium polykrikoides red tide and meso-scale variation of oceanographic environment around the Korean waters. Oceanographic conditions of Narodo island, where red tide usually first occurred during summer seasons were formation of the thermohaline frontal zone from 1995 to 2001. Huge C. polykrikoides red tides were observed in every uneven year during the past 7 years (1995~2001) and quasi-biennial oscillation also occurred in the oceanographic variations of sea surface temperature and salinity in the northern part of the East China Sea during the same years. The distribution area and moving pattern of C. polykrikoides red tides were definitely depended on the temporal and spatial variation of upwelling cold water originated form the southeastern coast of the Korean peninsula in summer season.

• Animal Systematics, Evolution and Diversity
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• v.29 no.1
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• pp.18-22
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• 2013

A recent study on the mitochondrial genetic variation of the Carassius auratus population in South Korea suggested that there are 3 distinct mitochondrial lineages in the country, and that they are geographically separated between westward rivers and southward rivers, respectively. In this study, the population genetic structure of amplified fragment length polymorphism (AFLP) of Carassius auratus was investigated. The results of analysis of molecular variance (AMOVA) supported the geographic distinction between westward and southward river populations, but only 3.66% of total genetic variance lies among these populations. The panmicticity of the AFLP genetic variation is backed up by the results of the neighbor-joining dendrogram drawn from a linearized pairwise $F_{ST}$ matrix and Bayesian clustering analysis. The discordance of genetic structure between mitochondrial and AFLP genetic variation may come from difference in effective population size between these markers and/or gene flow between westward and southward river populations through river capture events.

• Knowledge Management Research
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• v.17 no.3
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• pp.45-64
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• 2016

As the digital retail environement becomes prevalent, consumers are given greater opportunities to make purchases across physical and digital boundaries. Prior research emphasizes that the attractiveness of the digital or online channel is relatively determined by spatial specifics of physical locations. The overall market trend combined with prior research suggests that understanding spatial specifics becomes a key to managing both offline and online sales performance together. In this study, we focus on geographic variation in sales performance through offline and online channels and aim to investigate the channel-level sales difference between central and subsidiary areas. To this end, we obtain sales data of skincare and makeup products from a leading cosmetic company. Next, we examine spatial autocorrelations in data and then employ the spatial error models to study the effects of spatial specifics. The empirical findings are as follows. First, there are significant differences in category-specific and channel-level sales between central and subsidiary areas. Second, Moran's I statistics demonstrate the spatial autocorrelations of each variable. Third, spatial error models outperform simple regression models with lower AIC values. Finally, spatial specifics play a greater role in understanding online sales in subsidiary areas whereas they exert greater influence on offline sales in central areas. We believe our study advances the related theory and knowledge of multi-channel retailing and also contributes practically to location-dependent multi-channel strategies and sales data analytics.

• Health Policy and Management
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• v.6 no.2
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• pp.58-90
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• 1996

This study provides an empirical analysis of location competition for demand maximization by central place theory among physicians in nonmetropolitan areas of Korea. The results show that the primary care physicians distribute themselves evenly from urban communities to rural communities. The subspecialists, however, cluster together in major cities rather than decentralize themselves in rural counties. This study establishes the three statistical models : Primary care physicians, subspecialist physicians, and total physicians. Two models of primary care physicians and total physicians have a strong significance in multiple regression analysis (p=-.0001). The primary care model explains approximately 45% of the variation and the total physicians model explains approximately 70% of the variation in physician/1,000 population ratios across national counties. The subspecialist physicians model analysze the tobit regreassion because of the left consored and truncated values(57 cases = 0). In all three models, analysis of the coefficiencts for physician centralization degrees in the 0- to 5- and 5- to 10-km rings around the core county reveals each a positive and negative association betwee these degrees and the physician/1,000 population ratios in the core county. Also, the results provide moderate evidence that the relationship between clinic physicians and community hospitals is competitive, and the relationship between clinic physicians and pharmaceutists is synergistic. This suggests that public policy makers and local self-governing bodies must take an active role to ensure procider availability and the regional health planning in all nonmetropolitan areas of Korea.

• The Korean Journal of Zoology
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• v.34 no.1
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• pp.110-122
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• 1991

기름종개과의 N. toni, L. costota, N. multifasciata 3종에 대한 형태분석, 핵형분석 및 전기영동법에 의한 유전자 분석을 실시 각 종의 지리적 변이 및 계통적 유연관계를 조사하였다. 형태 측정치에 대한 discriminant 분석결과 연 yoni 월악산집단, 1. costoto 거제도집단 그리고 환multifasc지물 산철집단이 같은 종내 타 집단들과 형태상 완전히 분리 되어졌다. 핵형분석에서 N. muftifosciota와 1. costoto는 2n: 50으로 염색체수는 조사된 전 집단이 변리없이 동일하였다. N to티 삼척과 진부집단은 2n: 50으로 동일하였으나 고성집단은 2n=50, In : 48인 염색체상이 한개체에서 동시에 발견되었고, 인형성부위의 위치 및 형태가 타 집단과 차이가 있었다. 전기영동을 실시하여 총 28개의 유전자를 검출, 분석하였다. 3종중 N. multifosciata 청도집단의 유전적 변이 (HDi 123, HG : .160)가 가장 높았고, N. toni 고성집단이 가장 적었다. ( HD= .017, HG= .015). N. yoni 고성집단과 강릉집단은 각 집단의 고유한 genetic marker를 다수 갖고 있으며 타집단들과 유전적 근연관계도 매우 먼 것으로 나타나 각기 독립된 별종으로 추정된다.