• Journal of the Korean Geographical Society
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• v.45 no.2
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• pp.256-274
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• 2010

The aim of this study is to examine agglomeration patterns of advertising industries and spatial networks of advertisement production in Korea. The focus of analysis is the agglomeration pattern of advertising industries within Seoul because these are agglomerated in Seoul like other business services. Analysis methods are local Moran's I index and location quotient with the regional percentages of each sector's number of employees. Clusters in Gangnam Area are related to start-up advertising firms and global agencies entering domestic advertising markets. Network analysis is used to investigate the spatial networks of TV advertisement production between advertising agencies(AA) and film productions(FP). After transformation of AA-FP network matrix to regional matrix centrality index and brokerage scores are calculated. This analysis shows individual region's different role and position in the AA-FP network. Many agencies in or out of Gangnam Area outsource most advertisement makings to film productions in Gangnam Area. Advertising industry dusters in Gangnam Area is important as of the destination of advertisement production networks and the circulation of those networks.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.514-516
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• 2002

현재 많은 패킷 스위칭을 이용하는 네트워크로부터 발생되는 트래픽에서 burstiness 성질이 넓은 범위의 시간 축 상에 걸쳐 나타난다. 이런 트래픽 특성이 self-similar 현상을 보이고 있다는 것이 알려지고 있다. 본 논문에서는 다중연결 스위치의 self-similarity 특성을 분석하고 특히 각 스위치의 이용도와 self-similarity 와의 관계를 분석한다. 그리고 본 논문의 연구 결과는 ATM 등과 같은 초고속 스위치의 설계시 사용될 수 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.11-21
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• 2022

Drought occurs extensively over a long period and causes great socio-economic damage. Since drought risk consists of social, environmental, physical, and economic factors along with meteorological and hydrological factors, it is important to quantitatively identify their impacts on drought risk. This study investigated the relationship among drought hazard, vulnerability, response capacity, and risk in Chungcheongbuk-do using a structural equation model and evaluated their impacts on drought risk using Bayesian networks. We also performed sensitivity analysis to investigate how the factors change drought risk. Overall results showed that Chungju-si had the highest risk of drought. The risk was calculated as the largest even when the hazard and response capacity were changed. However, when the vulnerability was changed, Eumseong-gun had the greatest risk. The sensitivity analysis showed that Jeungpyeong-gun had the highest sensitivity, and Jecheon-si, Eumseong-gun, and Okcheon-gun had highest individual sensitivities with hazard, vulnerability, and response capacity, respectively. This study concluded that it is possible to identify impact factors on drought risk using regional characteristics, and to prepare appropriate drought countermeasures considering regional drought risk.

• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.47-56
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• 2013

The present study proposed a methodology to analyze the networking efficiency of arterial road networks. The methodology was motivated to design three-dimensional networks and to analyze the networking ability quantitatively, which is a novel approach compared to existing methods depending on the two-dimensional network definition and the qualitative analysis for improving arterial road networks. The method considered the interdependence between high-level freeways and low-level highways, the ITS-based information for traffic and road conditions, and the physical networking. These three factors were quantified by a networking index (NI), and the networking efficiency was measured by a networking rate (NR). The present study proved that the networking efficiency (NR) was influenced by travel information sharing (i.e., ITS) and physical factors. This supports the fact that the integrated improvements of physical and ITS factors are necessary for an arterial road. The proposed method was applied for an actual arterial road network. It was found that the nation-wide NR was higher than that for the metropolitan area, which might be due to the difficulty in switching between high- and low-level networks and the lack of ITS functions in the metropolitan area.

• Journal of the Korea Convergence Society
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• v.13 no.1
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• pp.51-62
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• 2022

AI-based speed prediction studies have been conducted quite actively. However, while the importance of explainable AI is emerging, the study of interpreting and reasoning the AI-based speed predictions has not been carried out much. Therefore, in this paper, 'Explainable Deep Graph Neural Network (GNN)' is devised to analyze the speed prediction and assess the nearby road influence for reasoning the critical contributions to a given road situation. The model's output was explained by comparing the differences in output before and after masking the input values of the GNN model. Using TOPIS traffic speed data, we applied our GNN models for the major congested roads in Seoul. We verified our approach through a traffic flow simulation by adjusting the most influential nearby roads' speed and observing the congestion's relief on the road of interest accordingly. This is meaningful in that our approach can be applied to the transportation network and traffic flow can be improved by controlling specific nearby roads based on the inference results.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.54-54
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• 2017

본 연구에서는 배수분구를 기준으로 서울특별시의 총 239개 지역 배수관망의 네트워크 특성을 깁스모형(Gibbs' model)을 이용하여 분석하였다. 깁스모형은 추계학적 하천망 모형으로 배수관망 네트워크의 특성을 검토하는데 사용된다. 또한 추계학적 모형이므로 같은 특성을 가지는 배수관망의 모의에도 이용된다. 분석결과 배수분구를 기준으로 서울시 총 239개 중 배수관망이 미 발단된 2개 지역을 제외한 237개를 값에 따라 총 8단계로 구분하여 분석하였다. ${\beta}$값이 $10^{-4}{\sim}10^{-1}$으로 비교적 비효율적인 배수관망은 전체 배수관망의 약 68%를 차지하는 것으로 나타났고, ${\beta}$값이 $10^0{\sim}10^3$으로 비교적 효율적인 배수관망은 전체 배수관망의 약 32%를 차지하는 것으로 나타났다. 따라서 서울시의 배수관망 특성은 비효율적인 관망이 지배적인 것으로 나타났다. 2010년과 2011년의 침수 흔적도와 ${\beta}$ 값의 상관분석을 수행한 결과 비효율적인 네트워크 특성을 가진 유역보다 상대적으로 효율적인 네트워크 특성을 가진 유역이 침수가 발생할 확률이 높다는 것을 밝혀냈다. 이러한 결과는 지속가능한 도시지역 배수관망 설계에 도움을 주고, 방재 관련 사업수립 및 침수원인 분석을 위한 연구에 기여할 것으로 판단된다.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.3
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• pp.492-507
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• 2008

Many classical network analysis methods approach networks in aspatial perspectives. Measuring network reliability and finding critical nodes in particular, the analyses consider only network connection topology ignoring spatial components in the network such as node attributes and edge distances. Using local network autocorrelation measure, this study handles the problem. By quantifying similarity or clustering of individual objects' attributes in space, local autocorrelation measures can indicate significance of individual nodes in a network. As an application, this study analyzed internet backbone networks in the United States using both classical disjoint product method and Getis-Ord local G statistics. In the process, two variables (population size and reliability) were applied as node attributes. The results showed that local network autocorrelation measures could provide local clusters of critical nodes enabling more empirical and realistic analysis particularly when research interests were local network ranges or impacts.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.3
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• pp.99-104
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• 2003

Ad-hoc is the wireless network and consists of moving Hosts in environments which don't have a network-based Frame. Because ad-hoc is considered as broadcast network and network which has useful benefits, multicast muting protocols have been studied on ad-hoc network For this work we scrutinized ad-hoc and multicast routing protocols presented in previous works. And we presents a protocol for Ad-hoc network.

• Annual Conference on Human and Language Technology
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• 2018.10a
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• pp.13-18
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• 2018

구문 분석은 문장의 구조를 이해하며 의미의 중의성을 해결하는 것이다. 일반적으로 한국어는 어순 배열의 자유도가 높고 문장 성분의 생략이 빈번한 특성이 있기 때문에 의존 구문 분석이 주된 연구 대상이 되어 왔다. 스택-포인터 네트워크 모델은 의존 구문 파서에 맞게 포인터 네트워크 모델을 확장한 것이다. 스택-포인터 네트워크는 각 단어에서 의존소를 찾는 하향식 방식의 모델로 기존 모델의 장점을 유지하면서 각 단계에서 파생된 트리 정보도 사용한다. 본 연구에서는 스택-포인터 네트워크 모델을 한국어에 적용해보고 이와 함께 어절 정보를 반영하는 방법을 제안한다. 모델의 실험 결과는 세종 구문 구조를 중심어 후위(head-final)를 엄격히 준수하여 의존 구문 구조로 변환한 것을 기준으로 UAS 92.65%의 정확도를 얻었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.5
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• pp.378-383
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• 2005

Traffic engineering is a technology that guarantees quality of service that users want and maximize inflection degree of network resources at the same time as evenly distributing traffic to whole network. To improve performance of network at traffic and resources level, traffic engineering aims at utilizing network resource efficiently and effectively and must be satisfied performance requirement concerned with traffic. In this paper, two models to embody traffic engineering are analyzed and finally functional structure of IP/WDM traffic engineering is explained.