• Journal of Astronomy and Space Sciences
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• v.10 no.2
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• pp.163-188
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• 1993

On the framework of Tolman spacetime model, the caustics around a local perturbed region in redshift is due to the local expansion rate induced by a local density inhomogeneity in real space. We have compared the caustics in redshift space, which are analytically obtained, with the observed redshift-distance patterns of galaxies which are belonging to Coma and Perseus clusters. For the Abell density distribution model and polytropic density profiles which are well-fitting the optical and X-ray observations, respectively, the size of caustics which is defined by "turnaround radius" of a local density perturbed region should give constraints on the sizes and masses of rich clusters and give also a clue to understand the state of hot X-ray emitting gas.

• Journal for History of Mathematics
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• v.37 no.4
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• pp.93-105
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• 2024

Research on the caustic, the envelope of light rays, began with the geometric optics studies of Huygens and others in the 17th century. One of the most important problems in optics in the 17th century was focusing the sun's rays. This was a problem that had to be solved in order to manufacture various practical optical instruments at the time. Beginning with research on the caustic during this period, the concept of envelope became generalized and expanded to various fields until the 19th century. This paper examines the mathematical history involved in the study of envelope curves. We compare several methods of defining the envelope and provide an example of calculating the envelope accordingly.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.673-684
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• 2011

Shinan-gun in Jeollanam-do has 1,004 islands which is the biggest number in the whole country. As most of the islands in Korea are secluded from the mainland or other islands, biological surveys are very important for the biogeographical perspective. Especially, the species diversity of insecta on an island plays an important role in the food stability of top predators, including birds. This study provides baseline academic resources for the preservation and management of uninhabited islands by providing information about the status of insects on the uninhabited islands in Docho-myeon, Jeollanam-do, Korea. As far as the appearance aspects of the insects in 28 uninhabited islands were 921 individuals, 122 species, 60 families or 12 orders. Ga Island showed the highest appearance as 32 species, 22 families or 9 orders. Appearance of specific insects was investigated unknown species: 1 species, southern characteristic species: 3 species, coastal dune species: 1 species, climate-sensitive indicator species: 1 species.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.837-841
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• 2007

최근 영상을 중심으로 여러 형태의 정보를 결합하여 저장하거나 전송하는 멀티미디어가 많은 관심을 받고 있다. 현재 카메라와 관련된 동영상 캡처기술은 Motion JPEG이 주류를 이루고 있으며, 텔레비전, DMB 등의 방송 분야 및 DVD, VCR 분야에서는 MPEG-2, MPEG-4, H.264 및 WMV9 등의 압축 코덱이 채용되고 사용되고 있다. 그러나 이러한 다양한 영상 표준방식은 디코딩시 호환성 문제가 발생하게 되고 이에 따라 통합 코덱 연구가 필요하다. 이에 본 논문은 일반적 스텝 양자화외에 데드존 양자화를 사용하고 "$4{\times}4$", "$4{\times}8$", "$8{\times}4$", "$8{\times}8$"의 다양한 블록크기의 변환을 지원하는 VC-1을 기반으로 한 ITIQ C언어를 통해 시뮬레이션하고 최적화된 결과를 VHDL로 구현하여 향후 통합코덱 연구에 응용 가능하도록 연구 및 분석평가 하였다. 설계결과 4:2:0의 YCbCr포맷의 최초 $16{\times}16$블록을 복원하는데 483~510클록이 소요되었고 Xilinx XCVPC100 FF1696-6 환경에서 93,128개의 게이트 수와 71.469MHz의 동작속도를 나타내었다. 이는 640*480 크기의 컬러영상을 디코딩 하는데 프레임 당 최대 0.0074초가 소요됨을 의미하며 초당 30프레임의 영상에서도 0.222초면 디코딩이 가능한 결과이다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.170-178
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• 2012

In this study, in order to provide an information for artificial cultivation of wild mushroom, the meteorological effects on wild mushroom appearance were examined using daily meteorological observations in Chiak National Park. The survey of wild mushroom appearance was carried out once a month from June to October. Under high temperature and humidity conditions in July and August, the appearance of wild mushroom was frequent. In contrast, lower number of wild mushroom appeared in October. Wild mushroom appearance was affected by solar radiation, relative humidity, precipitation, and soil water content whereas the impact of air and soil temperature was lower than that of other meteorological elements.

• Journal of the Mineralogical Society of Korea
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• v.4 no.2
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• pp.69-89
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• 1991

The anorthositic rocks and the many other plutons which are of different varieties and age were distributed in the northern extremity of the distributed areas of H-S anorthositic rocks. The purpose of this study was to find plutons which had comagmatic relationships, and to make clear the magmatic process of anorthositic magma. The plutons were classified, and the petrological and the geochemical characteristics of the plutons were compared and researched in this study. And, because, like anorthosite, the rocks which intrude in the deep crust accompany assimilation, an AFC model calculation was performed to make the differentiation process of the anorthositic rocks clear. The plutons in this area were classified into three groups, and the three groups were composed of the Precambrian anorthositic rocks and related rocks, the Jurassic gabbro, and the plutons of undnown age. The anorthositic magma was differentiated from the anorthositic rocks through the tonalite to the alkali-feldspar granite, and it was differentiated under K, Mg, Fe free/lack condition. It was found from the result of AFC model that the anorthositic rocks were differentiated by fractional crystallization, but they were assimilated with wall-rocks, and the assimilation was performed at the rate of r$\leq$0.1. The plutons which intruded the anorthositic rocks subsequently consisted of the gabbro, the megacrystic granite, the fine-grained granite, and the gneissose granite. But they were formed by the repeated intrusion of magma, which may, or may not, be of the same origin. According to the result of the RCF model, these plutons were differentiated by simple fractional crystallization, and they were assimilated relatively less than the anorthositic rocks.

• Parasites, Hosts and Diseases
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• v.26 no.4
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• pp.255-262
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• 1988

An epidemiological study on brugian filariasis was carried out in endemic areas including Cheju Island in Korea, with a brief review of literatures. The results showed that the incidence among residents has remarkably decreased in Cheju Island, which was the main endemic area. Reviewing available informations on the prevalence of filariasis reported in recent years and also judging from the present socio·economic conditions which enable people to practice personal protection against mosquitos, it can be said with confidence that alariasis has almost disappeared from Cheju Island and inland areas. The disease is considered to remain at a low level of endemicity in Hugsan Islands. Certainly mass diethylcarbamasine (DEC) treatment carried out in Cheju Island in the 1960s and 1970s and remarkable economic growth followed by improved living standard and altered life-style of inhabitants could all have combined effects on the disappearance of this mosquito-borne disease in this island. If the present trends go on, the possibility of resurgence of filariasis in Cheju Island is hardly postulated.

• Korean Journal of Culture and Social Issue
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• v.22 no.2
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• pp.203-222
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• 2016

Previous research has demonstrated that imagined contact is useful to reducing prejudice against minorities (e.g. Turner & Crisp, 2010). In this research, we investigated whether imagined contact increases attraction to physically unattractive women, and whether this effect is moderated by perceiver's physical attractiveness and appearance orientation in romantic relationships. Single male participants (n = 98) responded to items assessing their physical attractiveness and appearance orientation, and then were randomly assigned to one of the two conditions. In the imagined contact condition, participants were told to imagine communicating with a physically unattractive woman and come up with some interesting things about her. In the control condition, participants were told to simply imagine a physically unattractive woman. Next, participants saw a picture of a physically unattractive woman and rated her likeability, perceived attractiveness, and willingness to ask her out, which were averaged to form the composite measure of attraction. We found a significant main effect of imagined contact, as expected. This main effect was moderated by appearance orientation, but not by perceivers' physical attractiveness. The effect of imagined contact was significant among those low in appearance orientation, but not among those high in appearance orientation.

• Science of Emotion and Sensibility
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• v.11 no.3
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• pp.313-324
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• 2008

The purpose of the study is to investigate the influence of Ring-Back-Tone(RBT) music on the evaluation of the phone-call receiver's personality in dimensions of Openness, Extroversion, and Neuroticism. In a preliminary test, the subjects listened to 17 RBT music stimuli in random order and assessed the personality associated with liking for each music(N=15). Among the 17 RBTs, three were selected to be used in Experiments I and II and they were distinguished from each other in terms of the three personality dimensions(p<0.001). In Experiment I, the subjects were divided into four groups and were asked to make a call to interview an unknown receiver(N=60). Different RBT music was installed depending on the group to which each subject belonged. It was found that different RBT influences the caller's evaluation of the receiver's personality, supporting Hypothesis 1(p<0.001). Moreover, the ratings of the receiver's were highly correlated with those of the RBT music stimuli in terms of Openness(r=0.722, p<0.001) and Extroversion(r=0.753, p<0.001). In Experiment II, an identical experiment design was applied for a new group of subjects who were acquainted with the receiver(N=40). It was hypothesized that previous knowledge about a person would weaken the RBT effect. The results showed that RBT exerted no effect on the evaluation of the receiver's personality when the caller knew the receiver. It was also found that 12 personality traits, where each of the three personality dimensions is described by four traits, facilitated assessment of the character of the RBT music as well as the personality of the receiver.

• (The) Research of the performance art and culture
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• no.39
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• pp.801-833
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• 2019

This article has reviewed on the characteristics of the Beompae (Buddhist chanting) performed by Gyeongjaeeosan Wonmyeongchang(唱) based on the result of musical style of Gyeongjae Anchaebi-sori as defined under the previous studies. And, through the comparison with the Beompae performed by Songam-chang (唱), a same type of musical piece, it contemplates on musical differences between the two singers. Results of the study are shown as follows. of Gyeongjaeeosan Seolhoeinyu-pyeon and of Socheongsaja-pyeon are sunged as Yuchi-Seong(聲) among Anchaebi-sori. 'main melody type' and 'ending type' are generally similar to the musical characteristics of the Yuchi-Seong(聲), and the differences between the two singers are detected from main melody type D and ending type b. In particular, under of Socheongsaja-pyeon, only the type a is detected among the two types. becouse ending note of ending-type 'a' is ended with 'sol'. The basic frame of the Jjaimsae(musical form) has been clarified in the previous studies that the Jjaimsae of Yuchi-Seong(聲) has been maintained just the way it is. However, even for the same Seong(聲), the combination of the 'main melody type' of passage has not been unified, and depending on the musical piece, it has been discovered that the combination of the 'main melody type' has been diversely organized. of Gyeongjaeeosan Bongsongsajapyeon belongs to Pyeon-gae-seong(聲) broadly from the Anchaebi-sori and it is shown to be So-seong(聲) in details. In particular, in the previous studies, the 'ending melody' of So-seong(聲) and the closing melody of were similar with a slight difference for the 'ending melody'. Such a difference is relation to the characteristics for sequentially descending melody of Wonmyeong-chang(唱). The 'Jjaimsae(The musical structure)' is not much different from the previous studies, and the 'yeok-eum(weaving lyrics)' of Songam-chang(唱) has strong tendency of 3-sobak rhythm while the Wonmyeong-chang (唱) is shown the tendency of 2-sobak rhythm in general for the difference.