• 한국벤처창업학회:학술대회논문집
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• 2024.04a
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• pp.17-20
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• 2024

우리는 대표적인 디지털 플랫폼인 온라인 음식 주문 배달 산업을 대상으로 디지털 경제의 긴꼬리 효과를 계량화한다. 특히, 코로나19 시기를 거치면서 음식배달플랫폼 입점으로 인한 긴꼬리 효과의 변화 양상을 고찰한다. 배달의민족에 입점한 음식점 15,000곳을 무작위로 선별하고 이들 매장의 2019년부터 2021년까지 전체 주문 정보를 취합(aggregation)하여 선형로그변환 후 기울기를 추정하여 디지털 경제의 긴꼬리 효과를 실증 분석하였다. 2019년부터 2021년까지 관찰기간 동안 음식 배달 플랫폼 활용 음식점 주비모수 분포의 긴꼬리 효과는 강건하게 관찰되었다. 이는 코로나19 이후 음식배달 플랫폼을 통한 음식점의 디지털 전환이 틈새시장 확장에 일정 부분 기여하였음을 의미한다. 또한, 긴꼬리 효과는 객단가가 높을수록 매출액 상위 집단일수록 더 커지는 반면, 비황금 시간대 매출비중이 높은 경우 긴꼬리 효과가 통계적으로 유의하게 증가하지 않았다. 이 결과는 피자, 족발 등 단가가 높고 비교적 배달서비스가 활발한 카테고리에서 음식 주문 및 배달 산업의 디지털 전환 효과가 증가한다는 업계 실무자들의 관찰과 부합한다. 타 업종에서도 상대적으로 경쟁이 치열한 시장 구분에서 디지털 경제의 긴꼬리 효과가 보다 강건하게 관찰될 것이라고 여겨진다. 음식점 간 경쟁강도가 상대적으로 약한 비황금시간대 매출비중이 긴꼬리 효과에 통계학적으로 유의한 영향을 주지 않는다는 실증결과 또한 동일한 함의가 있다.

• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.52-56
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• 2016

A single specimen (700 mm in disc length) of Plesiobatis daviesi, belonging to the family Plesiobatididae, was firstly collected in the north-eastern coastal waters of Jejudo Island, Korea by using a bottom trawl on 24 October 2010. This species was characterized by having five pairs of gill openings, tail with one to three large spines, long snout length, long caudal fin, and pleated margin of nasal curtain. It is morphologically similar to Urolophus aurantiacus, but the former is distinguished from the latter by having longer caudal fin and snout length. We add P. daviesi to the Korean fish fauna and suggest the new Korean names, "Gin-kko-ri-huin-ga-o-ri-gwa", "Gin-kko-ri-huin-ga-o-ri-sok" and "Gin-kko-ri-huin-ga-o-ri" for the family, genus and species, respectively.

• Korean journal of applied entomology
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• v.57 no.2
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• pp.77-85
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• 2018

We surveyed 281 sites of tropical plants and 666 sites of fruit plants for three years (2015~2017) on Pseudococcus longispinus and Pseudococcus orchidicola which have not been surveyed domestically. In tropical plants, P. longispinus were found at 34 sites, while P. orchidicola were found at 87 sites. However, both species were not found in fruit plants. The developmental characteristics of P. longispinus and P. orchidicola were investigated under various temperatures. The female nymph of P. longispinus did not develop at $14^{\circ}C$ and the developmental period was the longest at $16^{\circ}C$ for 361.4 days and the shortest at $32^{\circ}C$ for 39.0 days. The longevity of female adult of P. longispinus was the shortest at $28^{\circ}C$ as 71.7 days. The number of offspring was highest at 177.7 at $32^{\circ}C$. The female nymph of P. orchidicola did not develop at $12^{\circ}C$. However, the developmental period was the longest at $14^{\circ}C$ for 184.9 days and the shortest at $28^{\circ}C$ for 21.5 days. The longevity of female adult of P. orchidicola was the shortest at 51.5 days at $28^{\circ}C$. The number of offspring was highest at 143.8 at $28^{\circ}C$. The net reproductive rate ($R_0$) and intrinsic rate of increase ($r_m$) of P. longispinus were 162.3 and 0.127 at $32^{\circ}C$, respectively. The $R_0$ and $r_m$ of P. orchidicola were 98.3 and 0.139 at $28^{\circ}C$, respectively. These results suggest that the optimum temperature of P. longispinus and P. orchidicola was $32^{\circ}C$ and $28^{\circ}C$, respectively. Therefore, we guess that they can never be able to survive the winter of Korea.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.40-47
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• 2000

The comparative toxicity of ten acaricides, seven insecticides and five fungicides to the two-spotted spider mite, Tetranychus urticae and its predators, Amblyseius womersleyi and A. eharai was evaluated by a leaf spray bioassay. Five of the acaricides tested, bifenazate, etoxazole, acequinocyl, flufenoxuron and chlorfenapyr were much less toxic to adult females of A. womersleyi and A. eharai than to T. urticae adult females. A. womersleyi adult females treated with five acaricides produced $52{\sim}93%$ as many eggs as untreated adult females. And A. eharai adult females treated with five acaricides laid $54{\sim}73%$ as many eggs as untreated adult females. The remaining acaricides showed high toxicity to adult females of A. womersleyi and A. eharai. All the insecticides tested were less toxic to T. urticae adult females than to adult females of A. womersleyi and A. eharai. However, tebufenozide and diflubenzuron did not significantly affect the survival and reproduction of adult females of A. womersleyi and A. eharai. All the fungicides tested showed low mortality (${\leq}24%$) to adult females of predatory mites. However, benomyl had significant effect on the reproduction of adult females of A. womersleyi and A. eharai. Four acaricides (bifenazate, acequinocyl, flufelloxuron and chlorfenapyr) were much less toxic to eggs of A. womersleyi and A. eharai than to T. urticae eggs. However, etoxazole caused relatively low hatchability ($58{\sim}62%$) of eggs of A. womersleyi and A. eharai. All the insecticides and fungicides tested did not significantly affect the hatch of eggs of predatory mites. It may be suggested from these results that four acaricides, two insecticides and four fungicides described could be Incorporated into the integrated mite management system with A. womersleyi and A. eharai in pear orchard.

• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.475-482
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• 1998

9 species of parasitoids emerged from chestnut gall samples collected at Chunchon, Kangwon in June to July 1995 - 1997, and 8 species emerged from gall samples at the 5 investigation sites in December 1997. The primary parasitoids among them were Torymus sinensis, Torymus geranii, Sycophila variegata, Megastigmus nipponicus, Megastigmus maculipennis, Eurytoma brunniventris, Ormyrus flavitibialis, Ormyrus punctiger, Eupelmus urozonus, while the secondary parasitoids were Torymus geranii, Sycophila variegata, Eupelmus urozonus, Eupelmus sp., Eurytoma setigera, Ormyrus punctiger. Torymus sp.. Some of secondary parasitoids were facultative hyperparasitoids, parasitizing the gall wasp as well as primary parasitoids, Among these natural enemies, Torymus sinensis was dominant at all sites. At Chunchon, the rate of gall formation showed decreasing tendency as the function of generation and the parasitism rate of Torymus sinensis showed increasing tendency gradually. But the rate of parasitization of the secondary parasitoids(Sycophila variegata, Eupelmus urozonus, Torymus geranii, Ormyrus puntiger) ranged from 4.0% to 10.5%. The mortality was high during June to October which was immature stage of Torymus sinensis, and mainly caused by secondary parasitoids. Torymus sinensis emerged from April to May and the estimated dates of 50% emergence was 21st April. The estimated dates of 50% emergence for the other, Sycophila variegata, Eupelmus urozonus, Torymus geranii, and Ormyrus puntiger were 25th April, 30th April, 4th May, and 22nd May, respectively.

• Animal Systematics, Evolution and Diversity
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• v.12 no.3
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• pp.211-220
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• 1996

A new species of the Diastylidae, Diastylis paratricinta, collected from the coasts of the Yellow Sea and Korea Strait, is described and illustrated. The new species resembles closely to Diastylis tricinta (Zimmer), 1903 from Japan, but is easily distinguished by bearing a horizontal ridge on each postero-lateral surface of the carapace.

• Korean Journal of Plant Taxonomy
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• v.45 no.1
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• pp.17-21
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• 2015

A new species belonging to Lycopodiaceae Mirb. Huperzia Bernh. s.l. is described and illustrated: Huperzia jejuensis B.-Y. Sun & J. Lim. H. jejuensis has been considered conspecific with H. integrifolia (Matsuda) B. ${\emptyset}$llg. ex. Z. Satou, but it is clearly distinguished by the characteristics of linear-lanceolate leaves with parallel margins from the base to the mid-part, minute dentate margins from the mid-part to the end of the leaf, and cuspidate gemma apex. Because the habitat of the new species was confined to Jeju Island, 'jejuensis' was chosen as the specific epithet of the scientific name of the new taxon.

• Animal Systematics, Evolution and Diversity
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• v.16 no.1
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• pp.113-122
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• 2000

Diaphanosoma dubium Manuilova, frequently confused with the species group of D. brachyurum Lieven and misidentified as an invalid species of D. leuchtenber-gianum Fischer in the Far East, was redescribed and illustrated. Redescription was based on the materials collected from various freshwater habitats at 76 localities in South Korea during the period from May 1978 to June 1999. Previous records of Diaphanosoma species from Korea were examined. D. dubium is well distinguished from other related species by having large head, longer swimming antennae with a thin seta on the outer distal side of basipod, carapace lacking dorsal spine at the posterior carapace margin, and fewer denticles on the ventro-posterior carapace margin.

• Korean journal of applied entomology
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• v.36 no.3
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• pp.224-230
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• 1997

A~nblyseius eharui and A. firllat~dic~w~esr e most abundant among Korean phytoseiid mites. The most favored plant\ chosen for habitats by Korean phytoseiid mites were Castanetr CI-enatcia nd P ~ L ~ ~.sIerLruIlaSt( i var. spontruleo. A. ehcirui, A. finltrr~(lic.us.a nd A. rc~omrrvleyia re most common and found on majority of plants observed.

• Korean Journal of Ichthyology
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• v.12 no.3
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• pp.203-207
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• 2000

The synaphobranchid eel, Dysomma anguillare was redescribed on the basis of a specimen collected from the Yellow Sea, Chollabuk-do, Korea. The D. anguillare was characterized by many fleshy plicae at the front of upper and lower jaws, dorsal fin originated in slight advance than pectoral fin base, degenerated eyes, very short trunk and long tail, anus located below near tip of pectoral fin and no scales.