• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2001년도 가을 학술발표논문집 Vol.28 No.2 (3)
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• pp.457-459
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• 2001

오늘날 MPLS 망에서의 제어 부분(control plane)을 다양한 장치의 스위칭(switching)과 포워딩(forwarding) 기술 및 계층을 포함할 수 있도록 확장하기 위해서 IETF에서 GMPLS 망이 제안되고 있다. 그리고 망은 보호(protection)와 복구(restoration)를 통해서 망의 생존성(survivability)을 지원해야만 한다. 망은 어떤 장애에서도 서비스가 제공될 수 있어야 한다. 본 논문은 Kini에 의해서 제안된[5] MPLS망에서 망의 장애 시에 망의 생존성과 효율성을 고려해서 복구하기 위해서, 백업 패스(Backup Path)를 설정하는 방법을 GMPLS에서 적용하려고 한다. 즉, GMPLS 망에서 망에 장애가 발생했을 때 효율적으로 복구하기 위해서, RSVF-TE(resource Reservation Protocol with Traffic Engineering)를 이용해서 백업 패스를 잡는다.

• 디지털콘텐츠학회 논문지
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• 제5권4호
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• pp.316-320
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• 2004

본 논문에서는 이미지 데이터의 저작권 보호를 위해 워터마크 삽입시 워터마크 영상에 DM-SS 기법을 적용하고 DM-SS 방식에서의 Burst성 에러에 강인한 Reed-Solomon 부호화를 적용하여 워터마크 복원에 대한 성능 개선을 하였다. 그리고 영상에 대한 외부 공격으로는 OFDM/QPSK 전송 시스템을 이용하여 전송 시 생기는 여러 가지 요인을 고려하였다.

• ETRI Journal
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• 제24권2호
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• pp.69-81
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• 2002

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP-centric signaling and control architecture based on the generalized multi-protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross-connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS-based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user-network interface and network-network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to generalized MPLS signaling.

• KIEE International Transactions on Power Engineering
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• 제4A권4호
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• pp.201-206
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• 2004

With the advent of distributed generation, power systems in general are impacted in regards to stability and power quality. Distributed generation has positive impacts on system restoration following a fault, higher reliability, and mitigation of effect due to voltage sag. However, distributed generation also has negative impacts on the decrease of reliability such as changes of protective device setting and mal-operation. Because bulk power systems consist of various sources and loads, it is complicated to analyze power systems that have distributed generation. The types of distributed generation usually are classified as the rotating machinery system and the inverter-based system. In this paper, distributed generation is designed as a synchronous generator, and the distribution system with its distributed generation model is simulated using EMTP. In addition, this paper shows the simulation results according to the types of distributed generation

• Journal of Forest and Environmental Science
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• 제36권2호
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• pp.91-112
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• 2020

In Ethiopia, dry land vegetation including the fairly intact lowland and western escarpment woodlands occupy the largest vegetation resource of the country. These forests play a central role in environmental regulation and socio-economic assets, yet they received less scientific attention than the moist forests. This study evaluated the woody plant species composition, population structure and carbon sequestration potential of the A. senegal woodland across three distance gradients from the settlements. A total of 45 sample quadrants were laid along a systematically established nine parallel transect lines to collect vegetation and soil data across distance gradients from settlement. Mature tree dry biomass with DBH>2.5 cm was estimated using allometric equations. A total of 41 woody plant species that belong to 20 families were recorded and A. senegal was the dominant species with 56.4 IVI value. Woody plant species diversity, density and richness were significantly higher in the distant plots compared to the nearest plots to settlement (p<0.05). The cumulative DBH class distribution of all individuals had showed an interrupted inverted J-shape population pattern. There were 19 species without seedlings, 15 species without saplings and 14 species without both seedlings and saplings. A significant above ground carbon (5.3 to 12.7 ton ha^-1), root carbon (1.6 to 3.6 ton ha^-1), soil organic carbon (35.6 to 44.5 ton ha^-1), total carbon stock (42.5 to 60.7 ton ha^-1) and total carbon dioxide equivalent (157.7 to 222.8 ton ha^-1) was observed consistently with an increasing of distance from settlement (p<0.05). Distance from settlement had significant and positive correlation with species diversity and carbon stock at 0.64^⁎⁎ and 0.78^⁎⁎. Disturbance intensity may directly influence the variation of species composition, richness and density along the A. senegal woodland. The sustainability of the A. senegal woodland needs urgent protection, conservation and restoration.

• 한국환경복원기술학회지
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• 제17권5호
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• pp.43-49
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• 2014

Fairy Pittas use the forest around the valley and Gotjawal as breeding places. This survey was conducted to investigate the characteristic of earthworms, specifically its population density, body size around the breeding site in Gotjawal and the forest around the valley areas from the middle of July to the end of July 2013. A total of 405 individual earthworms were collected in the 100 small established quadrats, in which 315 were found in Gotjawal and 90 were found in the forest around the valley area. The density of earthworms in Gotjawal was significantly higher compared to that forest around the valley area. It was also observed that the body size of earthworms was significantly different between Gotjawal and the forest around the valley area. Proportion of number of individuals which are larger than 7cm in body size was 43%(n=135) in Gotjawal and 84%(n=76) in the forest around the valley area, respectively. Soil area was not important factor to the density of earthworms. We suggest that Gotjawal can be considered as a suitable breeding site for Fairy Pitta because of the richness of its primary food in this area.

• 한국환경복원기술학회지
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• 제9권1호
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• pp.1-13
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• 2006

The recent environmental protection issue has diminished the supply of sand for soft ground improvements so much that the prices of sand have shown a sudden rise. Plastic material is one of substitutes for sand material, but plastic is nonperishable and doubtable if it has potential environmental hormone disrupting substances. Moderate-priced natural fiber drain board made with coconut coir and jute filter are in the spotlight recently as an alternative material for sand and plastic drain board etc. Natural fiber drain has not only competitive price but also a characteristic of assimilation into the soils after finishing of its own function. Discharge capacity of the fiber drain board evaluated by triaxial type discharge capacity test was relatively lower than that of plastic drain board. Nevertheless, settlement and pore pressure dissipation behaviors of the fiber drain board and the plastic drain board which were installed in the clayey soil during the composite discharge capacity test were almost similar. It was also found that biodegradation of the fiber drain board was in progress until 18 month after installation in the clayey soil, but they had still enough engineering properties to use at field.

• 한국조경학회지
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• 제38권5_2호
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• pp.206-213
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• 2010

This paper looks into how to preserve Gyeongju's natural environment and to restore its historic landscaping works, one of the greate factor that compose ancient city as a way of wisely preserving Gyeongju, one of the oldest cities of Korea. Gyeongju, a city based in its natural environment, is formated inside of a basin of mountains and streams. Mountains and streams are the major two factors when on thinks of preserving the ancient city of Gyeongju. Four mountains surrounding the city play a direct role in marking coordinates of major city landmarks, while streams influence the structure and formation of the city in a great deal. More precisely, mountains should be able to be seen from the center of the city and streams should be restored in a way that they can serve as scenic identities of their time. Efforts should also be put into restoring such elements as ancient gardens, royal forests and water ways. The research team believes that such efforts themselves will be a great methods in reclaiming historic values and significance of places of Gyeongju. Restoring an ancient city is not limited merely restoring a city in an artificial concept, it reaches to preserving natural environment as a backdrop of the city and traces of landscaping works. When it comes to restoring an ancient city, one must understand that preserving natural environment and historic landscaping works are as valuable as restoring city structure or constructional elements. We believe that defining subjects of ancient city restoration must be more precise, clear and detail down the road.

• 한국환경복원기술학회지
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• 제2권1호
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• pp.58-65
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• 1999

The purpose of this study was to evaluate the effect of rehabilitation measures on the fired woodland of Chesuk-bong in Mt. Chiri through the vegetation structure and comparison of growth pattern between natural seedlings and transplanted Abies koreana seedlings. It was also discussed the rate of standing and fallen trees of dead conifers in the management strategy for vegetation regeneration and protection of sub-alpine area. In this fired woodland, shrub layers consisting of Weigela subsessilis, Sambucus williamsii var. coreana, Rhododendron schlippenbachii, R. mucronulatum, Tripterygium regelii, and etc. were gradually expanded, and tree species such as Betula ermani, Sorbus commixta, Acer pseudosieboldianum, and Malus baccata var. mandshurica were also regenerated. The growth of height and crown width of Abies koreana seedlings transplanted for vegetation regeneration were a little lower than those of natural seedlings. The seedlings of A. koreana transplanted in this fired woodland grew about 50.6% normally, but the others had multi-branched or growth stopped by death of terminal shoot. Because the number of dead conifers by fire tend to be gradually increased as time passed, it can occurs to the soil erosion and landslide by weakness of the cohesion and resistance of soil. Therefore, it is consider that rehabilitation measures projects of the fired woodland in subalpine area may be more prevention a natural disaster like soil erosion, flood and landslide.

• 한국환경복원기술학회지
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• 제14권1호
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• pp.89-104
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• 2011

This study was carried out to the development of ecological planting model to make up of coastal windbreak forest on the Suncheon-bay in Sucheon-si, Korea. Make up of coastal windbreak forest in this site was needed for appropriate bioresource, biodiversity and ecological structure, and for conservation of the eco-tour resource and protection of human life and property by the unforeseen disaster from the coast. Based on the plant-social principle, the planting model of windbreak forest was developed to facilitate growth of trees, considering planting locations. The ecological planting model for the coastal windbreak was composed of warm temperate evergreen and windbreak forest which is spreading around the inland area in Korea. The horizontal forest style was composed of forest edge community and inner forest community, and the vertical forest style was composed of upper, middle, low and ground planting class. The target of the present model was quasi-natural forest, and the species of tree were selected based on the adaptability to surroundings depending on a goal to create a forest and forest style. To achieve both functions of wind break forest and visual effect in short period of time, small trees and seedlings were planted with high-density of 40,000/ha in an expectation of easy natural maintenance in the future. The significance of the present study is a suggestion for a guideline to create ecological coastal windbreak forest in the Suncheon-bay in which the harmony of human life and the ecological conservation is of great importance. Also, the ecological coastal windbreak forest model should be developed further through the long term monitoring after construction of forest.