• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.34.3-34.3
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• 2010

We present the results of flux monitoring of BL Lac object 0716+71 and 0954+65 at 22GHz and 43GHz. Both of the flat spectrum radio sources are known as Intraday variables (IDVs) which are characterized by fast flux variation on time scales of a day or less. In general, the IDV phenomenon is interpreted as the effect of refractive scintillation in the interstellar medium or the evidence of source intrinsic flux variation. The observations were made simultaneously at 22GHz and 43GHz with KVN Yonsei 21m radio telescope.

• 한국경제지리학회지
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• 제16권1호
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• pp.50-70
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• 2013

창조경제 새로운 패러다임의 변화는 사회적 관계의 변화에 영향을 끼치고 있으며, 소셜 네트워크 서비스 등의 발전에 따라 나타나는 새로운 관계의 공간적 특성에도 영향을 끼치고 있다. 본 논문에서는 이러한 변화에 영향을 미치는 동력을 '소셜 네트워크 리소스(social network resource)'로 명명하고, 그에 따라 나타나는 제반 특징과 경제지리학적 관점에서의 공간적 특성을 설명하고자 하였다. '소셜 네트워크 리소스'는 개방성과 공유, 참여, 협력의 특징을 보여주는 동시에, 공간적으로는 로컬과 글로벌의 특징을 모두 아우르는 소위 '트랜스 로컬리티'의 특성을 보이고 있는데, 서울시의 사회적 지식공유 웹 플랫폼인 '위키서울닷컴'의 사례를 통해 그러한 특성을 확인할 수 있었다. 특히, 물리적자원, 인적자원, 정보자원의 특성과 함께 관계자원으로서의 특징이 모두 나타나고 있으며, 이러한 특징에 공간이 투영되어, 사회적 관계가 공간에 표출되는 질적 공간의 특성 또한 나타남을 확인할 수 있었다.

• 천문학회보
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• 제37권2호
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• pp.239.1-239.1
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• 2012

This paper presents the results of one of early sciences with Korean VLBI Network (KVN): a large fringe survey of compact radio sources at 43GHz. We established the catalog of correlated flux densities in three ranges of baseline projection lengths of 637 sources from a 43 GHz (Q-band) survey observed with the Korean VLBI Network. Of them, 623 sources have not been observed before at Q-band with VLBI. The goal of this work in the early science phase of the new VLBI array is twofold: to evaluate the performance of the new instrument that operates in a frequency range of 22--129 GHz and to build a list of objects that can be used as targets and as calibrators. We have observed the list of 799 target sources with declinations down to $-40{\circ}$. Among them, 724 were observed before with VLBI at 22 GHz and had correlated flux densities greater than 200 mJy. The overall detection rate is 78%. The detection limit, defined as the minimum flux density for a source to be detected with 90% probability in a single observation, was in a range of 115--180 mJy depending on declination. However, some sources as weak as 70 mJy have been detected. Of 623 detected sources, 33 objects are detected for the first time in VLBI mode. We determined their coordinates with the median formal uncertainty 20 mas. The results of this work set the basis for future efforts to build the complete flux-limited sample of extragalactic sources at frequencies 22 GHz and higher at 3/4 of the celestial sphere.

• 천문학회보
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• 제37권2호
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• pp.240.2-240.2
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• 2012

AGN(Active Galactic Nucleus) consists of a supermassive black hole located at its center, an accretion disk around the black hole, and bipolar jets. Since May 2011, we have performed the MOGABA(Monitoring Of GAmma-ray Bright AGN) project for observing gamma-ray bright AGN once a week at multifrequencies using KVN(Korean VLBI Network) 21m radio telescopes. The MOGABA project is the observations for measuring the degree of polarization, polarization angle, and total flux of about 20 AGN at 22, 43 and 86GHz. By this project, we are able to investigate polarization characteristics, spectral index, and variation of rotation measure at radio wavelengths of gamma-ray bright AGN and to study possible relation between gamma-ray flares and magnetic field structure change in AGN. According to previous research, gamma-ray flares of some AGN are coincident with large changes in angle of linear polarization. In this paper we report the preliminary results of linear polarization and total flux at 22, 43, 86GHz of gamma-ray bright quasars 3C279 and 1510-089 showing noticeable variation of total flux at 22GHz in late 2011, and discuss possible correlation with gamma ray light curves.

• 천문학회보
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• 제46권1호
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• pp.60.3-61
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• 2021

The Korean VLBI Network (KVN) consists of three 21m radio telescopes installed in Seoul, Ulsan, and Jeju Island with the world's first 4-channel receiver that can observe four different frequencies (e.g., 22, 43, 86, 129 GHz) simultaneously. This receiving system of KVN is particularly effective in millimeter-wavelength VLBI (mm-VLBI) observations by compensating fast atmospheric fluctuations effectively. This technology is now being enhanced with a compact triple-band receiver, becoming the world standard for a mm-VLBI system. In 2020, KVN supported 54 observing programs (KVN: 28, EAVN: 26) including the 2nd KVN Key Science Program (KSP) which supports 8Gbps data recording rate and the East Asian VLBI Network (EAVN) programs. KVN also participated in the European VLBI Network (EVN) and GMVA (Global Millimeter VLBI Array) sessions regularly. Here, we report current status and future propsects of KVN.

• 제어로봇시스템학회논문지
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• 제11권12호
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• pp.984-990
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• 2005

The aim of this paper is to investigate a control framework for mobile robots, operating in shared environment with humans. The Intelligent Space (iSpace) can sense the whole space and evaluate the situations in the space by distributing sensors. The mobile agents serve the inhabitants in the space utilizes the evaluated information by iSpace. The iSpace evaluates the situations in the space and learns the walking behavior of the inhabitants. The human intelligence manifests in the space as a behavior, as a response to the situation in the space. The iSpace learns the behavior and applies to mobile agent motion planning and control. This paper introduces the application of fuzzy-neural network to describe the obstacle avoidance behavior teamed from humans. Simulation results are introduced to demonstrate the efficiency of this method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권6호
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• pp.2606-2626
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• 2016

This article investigates the distributed data storage problem in the space information network (SIN) using distributed fountain codes. Since space nodes in the SIN are resource-limited, in order to reduce energy consumption while improving the storage reliability, an efficient distributed storage based on fountain codes and probabilistic broadcasting (DSFPB) strategy is proposed. In the proposed strategy, source packets are disseminated among the entire network according to probabilistic broadcasting (PBcast), and the final degree distribution is close to the desired robust soliton distribution (RSD), this is benefited from the appropriate packets encoding procedure of the proposed strategy. As presented by the analysis and simulations, the total cost of data dissemination is greatly reduced compared with existing representative strategies, while improving the decoding performance.

• 한국지능시스템학회논문지
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• 제18권4호
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• pp.572-578
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• 2008

본 논문에서는 대규모 베이지안 망 구조 학습을 위해 제안되었던 R-CORE 방법의 탐색 공간의 크기에 대한 개략적인 분석과 실제 문제에 적용하였을 경우의 효과에 대한 실험적 결과를 제시한다. R-CORE 방법은 베이지안 망 구조 학습의 탐색 공간을 축소하기 위해 제안된 확률변수들의 재귀적 군집화와 오더 제한 방법이다. 알려진 벤치마크 베이지안 망을 이용한 분석을 통해, 제안되었던 R-CORE 방법이 worst case에는 기존의 방법과 유사한 탐색 공간을 가지나 평균적으로 기존방법보다 훨씬 적은 탐색 공간만을 고려한다는 것을 보인다. 또한 평균적으로 훨씬 적은 탐색 공간만을 고려하는 결과, 구조 탐색에서 기존 방법에 비해 상대적으로 적은 overfitting이 일어남을 실험적으로 보인다.

• 한국ITS학회 논문지
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• 제15권6호
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• pp.71-79
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• 2016

도시부 보행네트워크의 보행성 평가를 위해서 Space Syntax Theory(공간구문론)을 반영한 보행모형 구축이 요구된다. 공간구문론은 통합도를 도출하여 보행로의 중심성에 대한 정량적 평가지료를 제공한다. 보행모형은 이동성, 편리성, 안전성의 보행지표로서 보행성을 나타내는 정량적 판단근거를 제시한다. 그러나 보행네트워크에서 공간구문론을 반영하기 위해서는 회전지체 반영을 위한 네트워크구축기법의 검토가 요구된다. 특히 기존의 연구에서 제안된 나무기반 Dial 알고리즘은 회전지체 반영을 위하여 네트워크확장이 요구되었다. 본 연구는 덩굴망기반 Dial 알고리즘과 공간구문론의 통합방안을 제시하였다. 덩굴망기반 Dial 알고리즘은 인접링크의 사이에서 발생하는 회전지체를 포함하는 3단계 수행과정을 수행하므로 네트워크확장의 우회가 가능하다. 따라서 공간구문론의 축노드와 축노드가 만나는 시각교차점에서 회전지체가 발생하는 상황에서도 네트워크의 변형을 최소화하면서 시각거리와 물리거리를 일치시키는 측면에서 덩굴망기반 Dial 알고리즘이 활용이 필요하다. 도시부도로와 같이 보행이 복잡한 권역의 평가를 위해서 활용이 가능함을 향후 연구로 제시하였다. 특히 사례연구를 통해서 제안된 기법의 수행과정을 도출하였다.

• 대한건축학회논문집:계획계
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• 제35권5호
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• pp.21-30
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• 2019

The purpose of this study is to present the direction of the new space plan by reflecting the opinions of the user (student) in the existing standardized elementary school space planning. The purpose of this study is to investigate the activities of elementary school students by using socio - spatial network analysis method and to propose the direction of new elementary school space planning through the results. We analyzed the results of each centrality by using the analysis of closeness analysis, betweeness analysis, girvan-newman clustering, and concor analysis. The results of this study are as follows. First, it should be planned to use the classroom and the special room as one area by utilizing the corridor. Second, it should be planned that the outdoor space and the indoor space are closely related to each other by utilizing the hall, the lobby and the classroom. Third, the school should create a small space where physical activity is possible in an indoor space of the school. In order to improve the standardized elementary school space, this study proposes a method to reflect the opinions of the users in the school planning stage.