• Journal of Communications and Networks
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• 제17권2호
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• pp.100-109
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• 2015

Mobile phone carriers face challenges from three synergistic dimensions: Wireless, social, and mobile. Despite significant advances that have been made about social networks and human mobility, respectively, our knowledge about the interplay between two layers remains largely limited, partly due to the difficulty in obtaining large-scale datasets that could offer at the same time social and mobile information across a substantial population over an extended period of time. In this paper, we take advantage of a massive, longitudinal mobile phone dataset that consists of human mobility and social network information simultaneously, allowing us to explore the impact of human mobility patterns on the underlying social network. We find that human mobility plays an important role in shaping both local and global structural properties of social network. In contrast to the lack of scale in social networks and human movements, we discovered a characteristic distance in physical space between 10 and 20 km that impacts both local clustering and modular structure in social network. We also find a surprising distinction in trajectory overlap that segments social ties into two categories. Our results are of fundamental relevance to quantitative studies of human behavior, and could serve as the basis of anchoring potential theoretical models of human behavior and building and developing new applications using social and mobile technologies.

• 한국언어정보학회:학술대회논문집
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• 한국언어정보학회 2007년도 정기학술대회
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• pp.321-329
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• 2007

This paper reports on the application of network analysis approaches to investigate the characteristics of graph representations of Japanese word associations. Two semantic networks are constructed from two separate Japanese word association databases. The basic statistical features of the networks indicate that they have scale-free and small-world properties and that they exhibit hierarchical organization. A graph clustering method is also applied to the networks with the objective of generating hierarchical structures within the semantic networks. The method is shown to be an efficient tool for analyzing large-scale structures within corpora. As a utilization of the network clustering results, we briefly introduce two web-based applications: the first is a search system that highlights various possible relations between words according to association type, while the second is to present the hierarchical architecture of a semantic network. The systems realize dynamic representations of network structures based on the relationships between words and concepts.

• 한국컴퓨터정보학회논문지
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• 제25권7호
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• pp.47-55
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• 2020

본 논문에서는 앵커 프리 방법을 이용한 FCN(Fully Convolutional Network)기반의 1단계 다중 크기 얼굴 검출기를 제안한다. 최근 대부분의 연구들은 사전 정의된 앵커를 사용하여 얼굴이 있을 만한 위치를 예측한다. 그러나 사전 정의 앵커를 이용함으로써 학습 시 하이퍼 파라미터의 설정과 추가적인 계산이 필요하다. 제안하는 방법의 핵심 아이디어는 앵커 프리 방법을 사용하여 하이퍼 파라미터를 없애고 여러 개의 특징 맵을 사용함으로써 클래스 내 불균형 문제를 완화하는 것이다. 이 방법들은 다음과 같은 효과가 있다. 첫째로 사전정의 앵커를 없앰으로써 앵커와 관련된 하이퍼 파라미터와 추가적인 계산을 피한다. 둘째로 클래스 내 불균형을 완화하기 위해 여러개의 특징 맵으로부터 얼굴을 예측한다. 정량적 평가를 통해 제안하는 방법에 따른 검출 성능을 평가 및 분석한다. FDDB(Face Detection Dataset & Benchmark) 데이터 셋의 실험 결과에서 제안하는 방법이 효과가 있음을 증명했다.

• 한국건설관리학회논문집
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• 제10권4호
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• pp.151-164
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• 2009

전략적 제휴를 통해 형성되는 기업 간의 네트워크는 정보, 자원, 지식이 공유되고 확산되는 경로이자 새로운 자원으로서, 제휴네트워크의 구조적 특성은 기업의 성과에 영향을 미치고 있으므로 전략경영의 중요한 연구대상이 되었다. 본 연구는 건설기업간의 제휴네트워크를 대상으로 중앙성, 결속성, 등위성, 무척도성 등과 같은 구조적 특성을 분석하고, 이러한 특성이 성과에 미치는 영향을 확인한다. 연구 결과 건설기업 간의 제휴네트워크는 대부분의 기업이 상호 연결된 거대한 집단구조임과 동시에 일부의 허브 기업이 전체 제휴의 대다수를 차지하고 있음을 발견히였다. 그리고 네트워크에 포함된 기업을 5개의 역할 집단으로 분류할 수 있었으며, 상위집단의 경쟁과 협력 구도를 파악하였다. 또한 척도 없는 네트워크의 속성이 존재하여 제휴의 양극화가 진행 중임을 확인하였다. 최근 10년간의 네트워크에 대한 실증적 분석을 통해 참여한 프로젝트가 많고 네트워크에서 중심에 있는 기업의 성과가 지속적으로 높음을 검증하였다. 제휴를 통해 형성되는 네트워크에서 기업이 자리 매김(embedding)하는 미시적 행태와 네트워크의 거시적, 구조적인 속성은 참여한 기업에게 편익과 제약을 동시에 제공하고 있다. 이제 기업의 전략방향과 일치하는 네트워크전략의 수립과 포지셔닝 및 네트워크자원의 관리는 새로운 중요한 전략적 과제이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권4호
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• pp.1392-1403
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• 2015

The rapid development of both communication traffic and increasing optical network sizes has increased energy consumption. Traditional algorithms and strategies don't apply to controlling the expanded network. Immunization algorithms originated from the complex system theory are feasible for large-scale systems based on a scale-free network model. This paper proposes the immunization strategy for complex systems which includes random and targeted immunizations to solve energy consumption issues and uses traffic to judge the energy savings from the node immunization. The simulation results verify the effectiveness of the proposed strategy. Furthermore, this paper provides a possibility for saving energy with optical transmission networks.

• 한국정보통신학회논문지
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• 제26권9호
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• pp.1367-1373
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• 2022

본 논문에서는 셀프리 다중안테나 네트워크에서 하위 성능 사용자의 주파수 효율을 증대시키기 위한 전력 재할당 기법을 고려한다. AP(Access Point)는 사용자의 대규모 페이딩(large-scale fading) 채널 정보를 이용해 채널 세기에 비례하여 전력을 할당하여 전체 네트워크의 전력효율을 극대화한다. 다음으로 AP는 하위 성능 사용자의 주파수 효율을 증가시키기 위해 할당전력 중 임계비율 이상의 전력을 할당받은 사용자의 전력을 임계비율과 같아지도록 줄이고, 회수한 전력을 채널이 가장 나쁜 사용자에게 추가로 할당한다. 시뮬레이션을 통해 전력 재할당 기법을 통해 증가시킬 수 있는 하위 성능 사용자의 주파수 효율을 정량적으로 검증한다.

• Bioinformatics and Biosystems
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• 제2권2호
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• pp.71-74
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• 2007

Cell phenotypes are determined by groups of functionally related genes. Microarray profiling of gene expression provides us response of cellular state to its perturbation. Several methods for uncovering a cellular network show reliable network reconstruction. In this study, we present reconstruction of genetic regulatory network of inflammation bowel disease in human peripheral blood mononuclear cell. The microarray based on Affymetrix Gene Chip Human Genome U133 Array Set HG-U133A is processed and applied network reconstruction algorithm, ARACNe. As a result, we will show that inferred network composed of 450 nodes and 2017 edges is roughly scale-free network and hierarchical organization. The major hub, CCNL2 (cyclin A2), in inferred network is shown to be associated with inflammatory function as well as apoptotic function.

• Genomics & Informatics
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• 제1권1호
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• pp.7-19
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• 2003

The latest measure of the relative evolutionary age of protein structure families was applied (based on taxonomic diversity) using the protein structural interactome map (PSIMAP). It confirms that, in general, protein domains, which are hubs in this interaction network, are older than protein domains with fewer interaction partners. We apply a hypothesis of 'biological network evolution' to explain the positive correlation between interaction and age. It agrees to the previous suggestions that proteins have acquired an increasing number of interaction partners over time via the stepwise addition of new interactions. This hypothesis is shown to be consistent with the scale-free interaction network topologies proposed by other groups. Closely co-evolved structural interaction and the dynamics of network evolution are used to explain the highly conserved core of protein interaction pathways, which exist across all divisions of life.

• Asian Journal of Innovation and Policy
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• 제6권1호
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• pp.85-93
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• 2017

This paper focuses on the relationship between the characteristics of network and the productivity of scientists, which is rarely examined in previous studies. Utilizing a unique dataset from the Korean Citation Index (KCI), we examine the overall characteristics of the research network (e.g. distribution of nodes, density and mean distance), and analyze whether the network centrality is related to the scientific productivity. According to the results, firstly we have found that the collaborative research network of the Korean academics in the field of statistics and computer science is a scale-free network. Secondly, these research networks show a disciplinary difference. The network of statisticians is denser than that of computer scientists. In addition, computer scientists are located in a fragmented network compared to statisticians. Thirdly, with regard to the relationship between the researchers' network position and scientific productivity, a significant relation and their disciplinary difference have been observed. In particular, the degree centrality is the strongest predictor for the scientists' productivity. Based on these findings, some policy implications are put forward.

• 대한가정학회지
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• 제36권6호
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• pp.13-26
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• 1998

This study investigated first, socio-economic, residential characteristics, and values for future life among low-income family wives. Second, the relationship of these characteristics to the wives' stress was examined. The subjects were 249 mothers of urban low-income families whose children attended one of 20 daycare centers located in poor residential areas. The instruments included Social Network Scale, Home Stress Scale, and Occupation Stress Scale. Data were analyzed by means, standard deviations, frequencies, paired t-tests, and the stepwise multiple regressions. We found that a majority of the mothers and their husbands had high school educational status and simple labor or sales/service work status. They lived in rental houses or apartments. Their families of origin were a major source of emotional supports. Insufficient income for non-employed wives, long work hours and lack of free time for employed wives were a major stress. Levels of the wives' home-related job-related stress were negatively related to their own and their hudsbands' work status.