• The Bulletin of The Korean Astronomical Society
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• v.34 no.1
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• pp.116.1-116.1
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• 2009

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.43.1-43.1
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• 2010

We have carried out 43-GHz VLBI test observations of the Korean VLBI Network (KVN), which has obtained the first fringes at 22/43-GHz in 2009 (a talk by Sohn, Bong Won). In collaboration with VERA (VLBI Exploration of Radio Astrometry) in Japan, we have observed Active Galactic Nuclei (AGNs) and Orion-KL at 43GHz on 22nd and 23rd December, 2009, in order to evaluate the baseline- and image-sensitivity of KVN and KVN+VERA. In this talk we report the preliminary results of the VLBI test observations of the Korean VLBI Network at 43GHz.

• The Bulletin of The Korean Astronomical Society
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• v.34 no.1
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• pp.115.2-115.2
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• 2009

• Publications of The Korean Astronomical Society
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• v.20 no.1 s.24
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• pp.63-71
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• 2005

e-VLBI was invented to enhance the efficiency of VLBI (Very-Long-Baseline Interferometry) system by transmitting the data via high speed network. Korean VLBI Network (KVN) has a plan to construct e-VLBI system named e-KVN. High speed backbone network and efficient network model are essential to implement successful e-VLBI system. This paper introduces a network model based on PC cluster technology. The present status of high speed backbone network in Korea is overviewed. We suggest that the network link via Korea Advanced Research Network (KOREN) is one of feasible way for e-KVN. We also describe the principles of e-VLBI and protocol for network transmission such as VSI-E (VLBI Standard Interface - Electronic), RTP (Real-Time Transport Protocol) and RTCP (Real-Time Transport Control protocol).

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.59.1-59.1
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• 2010

We have carried out VLBI test observations of the Korean VLBI Network (KVN) at 22/43-GHz in collaboration with Japanese VLBI Exploration of Radio Astrometry (VERA). In order to evaluate the VLBI system of KVN, we have observed several sources using KVN+VERA. They consist of Active Galactic Nuclei (AGNs), which are expected to be compact and to have very well-known structures at spatial resolutions of 50-250 Mega-wavelengths, and Galactic star-forming regions and late-type stars, which have bright H2O and SiO maser emission regions. We have investigated baseline and imaging sensitivities of KVN+VERA. In this talk we report the preliminary results.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.4
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• pp.67-77
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• 2021

Space development has been led by the state due to huge investment, risks of development failure, and restrictions on international cooperation on technology development and transfer. For this reason, it has been developed mainly by some advanced countries and industrial network formed among them. However, Korean space industry is being promoted by the successful launch of 'KSLV-I' and 'CAS 500-I' and the space launch vehicle "KSLV-II" under development. Recently, Korea and U.S. agreed to end bilateral missile guidelines. Therefore it is expected that development of Korean space industry will be accelerated due to the disappearance of the constraining factors for the development of space launch vehicles. Accordingly, this study examined the development and formation of the Korean space industry through the framework of network analysis. Based on this, the effect of structural position in the industrial network as a resource on the performance of Korean space companies was examined. Panel analysis was applied. Through this study, ideas for fostering the domestic space industry and implications for national policy related with building an industrial ecosystem are derived. It contributes to the development of space industry in Korea.

• International Journal of High-Rise Buildings
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• v.8 no.1
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• pp.49-56
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• 2019

Against the background of the rapid development of the Shanghai Metro network, this paper attempts to establish an analytical approach to evaluate the impact of multiple transport network accessibilities on commercial space use in metro station areas. Ten well-developed metro station areas in central Shanghai are selected as samples. Commercial space floor area and visitors in these areas are collected. Using ArcGIS and Spatial Design Network Analysis, the Shanghai Metro network and road network are modeled to compute diversified transport accessibilities. Evidence from land use and commercial space floor area within a 0-to-500-meter buffer zone of stations is consistent with location and land-use theory: commercial land use is concentrated closer to stations. Correlation analysis suggests that hourly visitors to the shopping mall are mainly influenced by metro network accessibility, while retail stores and restaurants are affected by both metro and pedestrian accessibility.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.172-174
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• 2007

In this paper, we designed a embedded system that will perform a primary role of Tangible Space implementation. This hardware includes function of image capture through camera interface, image process and sending off image information by LAN(local area network) or WLAN(wireless local area network). We define this hardware as a network based Visual Agent Platform for Tangible Space, This Visual Agent Platform includes the software that is RTLinux and CORBA

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.42.2-42.2
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• 2010

2009년부터 2010년에 걸쳐 22 및 43GHz 대역에서의 KVN 단일경 시험관측이 이루어졌다. KVN 관측소는 연세대학교, 울산대학교, 탐라대학교에 위치하고 있으며, 시험관측의 주된 내용은 안테나 지향모델 구축, 22/43 GHz 빔 정렬, 이득곡선 측정 및 안테나 효율측정 등이다. 구축된 지향오차의 정밀도는 세 곳의 관측소 모두 rms가 5초 이내였으며, 두 빔도 5초 이내로 정렬되어 있음이 확인되었다. 안테나 효율은 22 및 43GHz에서 모두 60%를 넘는 값을 얻을 수 있었다.

• Journal of Electrical Engineering and information Science
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• v.3 no.2
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• pp.151-157
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• 1998

Free-space optical interconnection networks can be classified into two types, space variant and space invariant, according to the degree of space variance. In terms of physical implementations, the degree of space variance can be interpreted as the degree of sharing beam steering optics among the nodes of a given network. This implies that all nodes in a totally space-invariant network can share a single beam steering optics to realize the given network topology, whereas, in a totally space variant network, each node requires a distinct beam steering optics. However, space invariant networks require mechanisms for distinguishing the origins of incoming signals detected at the node since several signals may arrive at the same time if the node degree of the network is greater than one. This paper presents a signal source encoding scheme for distinguishing incoming signals efficiently, in terms of the number of detectors at each node or the number of unique wavelengths. The proposed scheme is solved by developing a new parallel genetic algorithm called distributed asynchronous genetic algorithm (DAGA). Using the DAGA, we solved signal distinction schemes for various network sizes of several topologies such as hypercube, the mesh, and the de Brujin.