• 한국환경생태학회지
• /
• 제25권3호
• /
• pp.412-420
• /
• 2011

본 연구는 1975년부터 2006년까지 서울시 녹지 연결망의 시계열 변화를 그래프 이론을 적용하여 공간의 다중규모(multi-scale)에서 정량적으로 분석하였다. 분석대상 시기 동안, 서울시 녹지 연결망의 변화가 크게 나타난 공간 규모는 녹지 간 1,000 ~ 1,600 m 거리였다. 1990년 이후 난개발로 단편화되고 훼손되었던 녹지들과 연결망이 점차 복원되고 있음을 확인할 수 있었다. 2006년 개별 녹지의 연결망 분석을 통해, 핵심 녹지와 징검다리 녹지의 두 가지 유형의 녹지 연결망 분포를 확인하였다. 서울시 녹지 분포는 연결성 중요도 지수와 상관관계가 높아서, 남쪽과 북쪽의 가장자리에 핵심 녹지가 분포하고 동쪽, 서쪽, 중앙에 매개 중심성이 높은 징검다리 녹지가 분포함을 정량적으로 표현할 수 있었다. 따라서 서울시 녹지 연결망은 그래프 이론을 적용하여 연결 중심성, 매개 중심성, 연결 중요도 지수 등으로 정량적으로 표현될 수 있다.

• Journal of Information Technology Applications and Management
• /
• 제18권1호
• /
• pp.55-74
• /
• 2011

The growth in the use of ubiquitous computing based on mobile services as an enabler to conduct business more effectively has been phenomenal. Technology acceptance model (TAM) has been applied in different contexts to examine a wide range of information technologies (IT). As more and more companies are finding ways to utilize ubiquitous computing based on mobile services, an important issue is to understand what factors will impact the decisions of consumers in adopting the services. Based on TAM with three additional groups of external factors, i.e., service-related factors (ubiquitous access, context awareness) and technology-related factors (perceived security risk, network connectivity) that are theoretically justified as having influence on both perceived usefulness and perceived ease of use which are additionally considered, a research model for the investigated technology acceptance was developed and empirically examined, using responses from more than intended users of ubiquitous computing based on mobile services. The specific purposes of this study are as follows. Firstly, this study is to identify service beliefs considering unique characteristics for ubiquitous services such as perceived ubiquitous access and perceived context awareness. Secondly, this study is to investigate network characteristics beliefs such as perceived security and perceived connectivity. Thirdly, this paper investigates the relationship among variables such as ubiquitous characteristics, network characteristics, behavioral beliefs, and intention to use ubiquitous web services. This study uses a structural equation model to test the research model. The major results of this study are as follows. Firstly, ubiquitous access has a influence on perceived usefulness and perceived ease of use. Context awareness has an influence on perceived usefulness. Secondly, User familiarity has an influence on perceived usefulness and perceived ease of use, and intention to use. User innovativeness has an influence on perceived ease of use. Thirdly, perceived security risk has an influence on perceived usefulness and perceived ease of use. Network connectivity has an influence on perceived usefulness and perceived ease of use. Fourth, there exist differential effects among factors in structural model among information, transaction, and entertainment services.

• 대한불안의학회지
• /
• 제14권2호
• /
• pp.63-70
• /
• 2018

It has been suggested that aberrant self-referential processing (SRP) is one of the important components of the explanatory models of social anxiety disorder (SAD). The default mode network (DMN), which reflects intrinsic brain functions, is known to play a critical role in SRP. Recently, resting state functional magnetic resonance imaging (fMRI) research on the functional connectivity in the brain network has gained greater attention as a tool to elucidate the neurobiological basis of various psychiatric disorders. We reviewed resting state fMRI studies that investigated the resting state functional connectivity (RSFC) of the DMN in SAD. Despite of the heterogeneity of the analytic methods and occasional negative findings, most studies consistently reported abnormalities of RSFC within the DMN, suggesting that the DMN may be significant neural correlates of aberrant SRP in SAD. Also, changes in RSFC of the DMN are associated with clinical improvements of therapeutic interventions. Moreover, emerging findings provide the basis for potential use of RSFC as a complementary method in diagnosis of SAD. Ongoing and future research to investigate RSFC of the DMN could broaden our understanding regarding the neurobiological basis of SAD, and contribute to the development of novel treatments for SAD.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회 1997년도 추계학술대회발표논문집; 홍익대학교, 서울; 1 Nov. 1997
• /
• pp.138-141
• /
• 1997

In this study, a simulation model is developed to analyze the effects of routing and scale-economy of transmission facilities on the traffic network topology and investment cost changes in a metropolitan telephone network. Computational experiments showed that the wide deployment of bifurcated routing in a dual-homing configuration reduces significantly the traffic network connectivity and the investment cost. Its enhanced version, when combined with the subscriber network cost model, can be used as a prototype cost proxy model for figuring out the access charges in a multi-operator environment.

• 한국HCI학회:학술대회논문집
• /
• 한국HCI학회 2008년도 학술대회 2부
• /
• pp.456-459
• /
• 2008

현재는 CE 와 PC 를 중심으로 한 디지털 컨버전스의 시대이지만, 그에 반대급부로 많은 제품군의 다양화가 동시에 이루어지고 있다. 각 제품들은 독립적으로 기능을 수행하고 있지만, 유비쿼터스, 홈 네트워크의 개념이 부각되며 모든 제품들은 추후 네트워크상에 연결되게 될 것이며, 기기와 기기간의 연결을 통한 사용에 대한 시장의 요구가 지배적으로 부각될 것이다. 이러한 추세로 볼 때, 제품의 다양화는 결국 수 많은 경우의 수를 가지는 연결형태를 낳을 수 밖에 없으며 제품의 다양화에 따른 수 많은 연결형태에 대한 정의와 제어구조가 필요하다. 이에 더불어 다양한 제품들을 네트워크 상에서 유기적으로 연결하여 사용할 수 있는 다양한 디자인 방법론이 제시되어 왔지만, 실제 사용자의 사용행태 및 각 기기가 가지고 있는 기능적인 특정을 반영하는 기준이 정립되어 있지 않은 경우가 많다. 본 논문에서는 이러한 많은 경우의 수의 연결형태를 구분하고, 제어구조를 확립하기 위한 기기간 연결성디자인방법론을 제시하고 있다. 연결성디자인 가이드라인은 폭 넓은 기기간 연결을 제공하여야 하며, 여러 기기간의 동시제어(3-box 모델)에 대한 고려도 있어야 한다. 연결성디자인의 가이드라인을 제시하기 위해 우리는 사용자의 제품경험단계를 연결, 설정, 사용, 해제의 4 단계로 나눔으로써 수 많은 경우의 수의 연결형태의 구분에 대한 초기적인 정의를 하였다. 이러한 초기적인 정의를 바탕으로, 세부적인 연결형태의 구분을 위해 본 논문에서는 각 사용자 경험단계별 연결형태의 기준을 제시한다.

• Korean Journal of Radiology
• /
• 제24권3호
• /
• pp.247-258
• /
• 2023

Objective: To localize the neuroanatomical substrate of rapid eye movement sleep behavior disorder (RBD) and to investigate the neuroanatomical locational relationship between RBD and α-synucleinopathy neurodegenerative diseases. Materials and Methods: Using a systematic PubMed search, we identified 19 patients with lesions in different brain regions that caused RBD. First, lesion network mapping was applied to confirm whether the lesion locations causing RBD corresponded to a common brain network. Second, the literature-based RBD lesion network map was validated using neuroimaging findings and locations of brain pathologies at post-mortem in patients with idiopathic RBD (iRBD) who were identified by independent systematic literature search using PubMed. Finally, we assessed the locational relationship between the sites of pathological alterations at the preclinical stage in α-synucleinopathy neurodegenerative diseases and the brain network for RBD. Results: The lesion network mapping showed lesions causing RBD to be localized to a common brain network defined by connectivity to the pons (including the locus coeruleus, dorsal raphe nucleus, central superior nucleus, and ventrolateral periaqueductal gray), regardless of the lesion location. The positive regions in the pons were replicated by the neuroimaging findings in an independent group of patients with iRBD and it coincided with the reported pathological alterations at post-mortem in patients with iRBD. Furthermore, all brain pathological sites at preclinical stages (Braak stages 1-2) in Parkinson's disease (PD) and at brainstem Lewy body disease in dementia with Lewy bodies (DLB) were involved in the brain network identified for RBD. Conclusion: The brain network defined by connectivity to positive pons regions might be the regulatory network loop inducing RBD in humans. In addition, our results suggested that the underlying cause of high phenoconversion rate from iRBD to neurodegenerative α-synucleinopathy might be pathological changes in the preclinical stage of α-synucleinopathy located at the regulatory network loop of RBD.

• 한국지역지리학회지
• /
• 제21권1호
• /
• pp.1-20
• /
• 2015

이 논문은 네트워크도시 이론의 정책적 함의와 분석적 유용성을 고찰하면서 그 한계를 보완하고, 이를 영남권 지역에 적용하여 지역 발전을 위한 전망을 제시하고자 한다. 네트워크도시는 상대적 자립성을 가진 중소도시들이 네트워크를 구축하여 상호보완성과 시너지를 확보함으로써 개별 도시와 권역의 발전을 동시에 추구한다는 점에서, 지구 지방화 과정에 대한 도시 및 지역의 적극적인 대응방안이 될 수 있다. 그러나 네트워크도시 이론과 이를 응용한 경험적 연구가 가지는 한계와 문제를 해소하기 위하여, 네트워크도시의 연계성을 경험적으로 고찰하기 위한 분석기법의 체계화, 연계성 지표의 확장, 네트워크도시에 내재된 규범성의 재확인, 네트워크도시를 위한 협력적 거버넌스 구축, 네트워크도시와 연계된 도시 내부 공동체의 발전 방안의 모색 등이 요구된다. 이 이론을 활용한 영남권 도시지역에 관한 예비적 분석에서 이 지역은 네트워크도시에 근접하고 있지만, 명확히 네트워크도시라고 판단하기는 어렵다. 그러나 규범적, 정책적 측면에서 영남권 도시지역이 네트워크도시를 지향하기 위하여, 권역 내 도시 및 지역들 간 교통통신 인프라의 확충, 경제적 상호연계성의 강화, 협력적 거버넌스의 구축, 권역 차원의 기능적 연계성의 국지적 착근화가 필요하다는 점이 제시된다.

• 한국환경복원기술학회지
• /
• 제17권3호
• /
• pp.75-86
• /
• 2014

An urban ecosystem is a complex system that includes social, economic and ecosystems. Therefore, it is important to consider its environmental capacity while developing a city plan. Most of the plans, however, consider only the social aspects, which fragments the green spaces and disturbs the movement of species. Sungnam has approximately 100 parks with unexecuted development plans and with great potential to contribute towards urban ecosystem enhancement. Therefore, this study applied network analysis to prioritize the development of city parks and contribute towards improving the green network, with Parus spp. as the target species. To compensate for the drawbacks of binary and possibility-based network analysis, this study included two indices, namely $BC^{PC}_K$, $BC^{IIC}_K$, $dPCconnector_k$ and $dIICconnector_k$. These indices make it possible to find patches that could play an important role in green network enhancement. The urban park with greater value gets a higher priority to be transformed into a park. Thus, our methodology could prove to be very useful in prioritizing the undeveloped parks, thereby supporting decision-making.

• Journal of Communications and Networks
• /
• 제9권3호
• /
• pp.282-295
• /
• 2007

Due to the nature that high datarate leads to shorter transmission range, the performance enhancement by high datarate 802.11 WLANs may be degraded when applying high datarate to an 802.11 based multihop ad hoc network. In this paper, we evaluate, through extensive simulations, the performance of multihop ad hoc networks at multiple transmission datarates, in terms of the number of hops between source and destination, throughput, end-to-end delay and packet loss. The study is conducted based on both stationary chain topology and mesh topologies with or without node mobility. From numerical results on network performance based on chain topology, we conclude that there is almost no benefit by applying the highest datarate when the chain length is 6 hops or more. With node mobility in mesh topology, the benefit of using high datarate diminishes at even shorter number of hops. To explore the main reasons for this behavior, analyses on multihop end-to-end throughput and network k-connectivity have been conducted later in the paper, and correspondingly an auto-rate adaptation algorithm has been proposed.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권10호
• /
• pp.5014-5034
• /
• 2016

This paper discusses how to effectively guarantee the coverage and connectivity quality of wireless sensor networks when joint perception model is used for the nodes whose communication ranges are multi-level adjustable in the absence of position information. A Connect Coverage Algorithm Based on Joint Sensing model (CCAJS) is proposed, with which least working nodes are chosen based on probability model ensuring the coverage quality of the network. The algorithm can balance the position distribution of selected working nodes as far as possible, as well as reduce the overall energy consumption of the whole network. The simulation results show that, less working nodes are needed to ensure the coverage quality of networks using joint perception model than using the binary perception model. CCAJS can not only satisfy expected coverage quality and connectivity, but also decrease the energy consumption, thereby prolonging the network lifetime.