• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.9
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• pp.2246-2267
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• 2013

BitTorrent is one of the most important applications in the current Internet. Despite of its interest, we still have little knowledge regarding the connectivity properties of real BitTorrent swarms. In this paper we leverage a dataset including the connectivity information of 250 real torrents and more than 150k peers to carefully study the connectivity properties of peers. The main topology parameters of the studied swarms suggest that they are significantly less resilient than random graphs. The analysis of the peer level connectivity properties reveals that peers continuously change more than half of their neighbours. Furthermore, we also find that a leecher typically keeps stable connections with a handful of neighbours with which it exchanges most of its traffic whereas seeders do not establish long-term connections with any peer so that they can homogeneously distribute chunks among leechers. Finally, we have discovered that a significant portion of the studied peers (45%) have an important locality-biased neighbourhood composition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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• pp.338-343
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• 2006

Histological observations of the barbels of torrent catfish (Amblycipitidae) in Korea are reported. The bullhead torrent catfish (Liobagrus andersoni) and Korean torrent catfish (L. obesus) have eight obvious barbels in two pairs each on the maxilla and mandible. Each barbel is composed of an epidermis, dermis, and central cartilagerod. The epidermis of the maxillary and mandibular barbels of the bullhead torrent catfish is thicker than that of the Korean torrent catfish (P<0.05) and is formed of stratified epithelium that contains many cutaneous taste buds and a few small club cells. There are many taste buds on the upper part of each barbel. The dermis consists of loose connective tissue fibers that enclose blood vessels and bundles of nerve fibers. The barbels of these fish can be categorized into stiff and flexible types and are accessory, feeding, and sensory structures. Our results validate the barbels as gustatory receptor organs for these fishes.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.176-181
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• 2013

The impacts of habitats changes of benthic macroinvertebrae species and individuals of the torrents due to construction of torrent structures can be summarized as follows. Approximately 16 to 40 species and 352 to 4,333.3 individuals of benthic macroinvertebrae were found around the local position of the torrent structures. Construction of torrential structures can increases the stability in the riverbed by preventing vertical corrosion and reducing the flow rate. However, if pond is created due to increase flow rate of rainfall, the temporal confusion of micro-habitats may lead to decrease in the number of species and induce reduced number of diversity as well as cause simplification in the community structure. Therefore, erosion control structures in torrent cause influence on the habitual ecosystem, though there are differences in the degree per distance depending on the types and heights of the structure. Before establishing torrent erosion control structure in mountainous torrent area, ecosystem status should be studied carefully from the planning stage and torrent habitats should be protected by deciding type, height and scale of structure, to minimize the influence on local habitants.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.226-227
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• 2010

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.48-53
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• 1998

In this paper, the new electrochemical machining method is proposed for the micro unit fabrication by using the point electrode tools. The precision shape control capacity is improved by using the point electrode method. It was observed that an electric discharge phenomenon occurs during the electrochemical machining process by using the spraying and torrent type electrolyte supply method.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.65-77
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• 2013

Recently the ratio of the Internet traffic generated by video streaming applications including video-on-demand (VOD) is getting higher and higher, while P2P-based naive content distribution has been the main source of the Internet traffic in the past. As a result, the paradigm of cooperatively distributed systems (e.g., P2P) is changing to support streaming applications. Most P2P assisted approaches for video streaming today are based on Bit Torrent thanks to its simplicity of implementation and easy adaptability. They, however, have immanent vulnerability to free-riding inherited from Bit Torrent, which inevitably hurts their performance under limited system resources with free-riding. This paper studies the weakness to free-riding of existing Bit Torrent-based video streaming applications and investigates the adaptability of T-Chain (which was originally designed to prevent free-riding in cooperatively distributed systems) to video streaming applications. Our experiment results show that the video streaming approach based on T-Chain outperforms most existing Bit Torrent-based ones by 60% on average under limited system resources with free-riding.

• KOGO NEWS
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• v.11 no.2
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• pp.3-6
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• 2011

• Journal of Contemporary Eastern Asia
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• v.11 no.1
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• pp.21-29
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• 2012

The popularity of the Internet has affected international politics in many ways; however, it is seemingly overlooked by most scholars, and in particular, realists who view the Internet as low-politics. This article argues that the impact of the Internet on international politics should not be underestimated. By focusing on the capabilities of the Internet in general and P2P networks in particular, this paper shows how the Internet is able to disseminate soft power resources. This is demonstrated by an examination of the dissemination of Japanese soft power resources through BitTorrent. Finally, it is concluded that the Internet is a plausible agent for distributing the resources of soft power; however, once disseminated, soft power resources do not always transform into soft power. In the end, contextual conditions within states always apply.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.85-88
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• 2011

요즘은 "손 안의 컴퓨터"라 불리는 smartphone이 전 세계적으로 열풍이다. 휴대전화가 보급되어 일반사람들도 이동하면서 전화가 가능하게 된 지 얼마 되지도 않았다. Blackberry, apple, HTC, nokia, samsung, LG 등 수많은 제조업체들이 이미 smartphone 시장에 뛰어든 지 오래이며, 이들 간의 경쟁은 갈수록 치열해지고 있다. 이 논문은 이러한 우리들의 생각을 반영하여 만들게 된 프로그램에 대한 것이고 따라서, "smartphone OS 중 가장 개발자를 위한다"는 평을 받고 있는 Android 기반의 P2P 프로그램에 대한 것이다. P2P는 많은 사람들이 파일공유를 목적으로 사용하는 프로그램으로, 이미 컴퓨터에서는 많이 사용되고 있다. 이는 트래커 서버 운영을 기반으로 한다. Android smartphone에서도 이러한 수요는 앞으로 급증할 것으로 보여서, 이 프로그램의 개발은 유저의 요구를 반영할 수 있는 의미있는 작업이라 하겠다.

• Development and Reproduction
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• v.22 no.1
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• pp.9-18
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• 2018

This study was conducted to investigate the skeletal development of bullhead torrent catfish, Liobagrus obesus larvae and to utilize them as basic data for the taxonomic study of Liobagrus larvae. Skeletal development was observed by being divided into cranium, visceral skeleton, shoulder girdle bone, pelvic girdle bone and vertebra. On the first day after hatching, the pre-larvae had an average total length of 7.92 mm, and a line-shaped parasphenoid ossified in the cranium. In the jaw bone, the dentary supporting the lower jaw and the maxillary supporting the upper jaw were ossified. In the anterior abdominal vertebrae of the vertebra, seven centrums began to ossify and five neural spines ossified simultaneously. On the 3 day after hatching, pre-larvae had an average total length of 8.95 mm, and the prefrontal ossified in cranium. The number of abdominal vertebrae was increased to 14, and three parapophysis developed from the front side. On the 24th day after hatching, post-larvae had an average total length of 15.2 mm and the epural bone ossified in coccyx. The parhypural bone was ossified, and ossification of coccyx and pelvic girdle bone was completed. On the 30th day after hatching, the average total length of the juvenile was 17.8 mm, and the ossification of cranium and visceral skeleton was all completed while the preorbital and three suborbitals were ossified in the orbital region of the cranium.