• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.35-45
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• 2012

Existing studies on land values tend to show the use of simple euclidean distances as the accessibility variable and OLS as the analysis method. However, applying such euclidean distance-based accessibility to dense CBD areas has limitations in the incorporating the characteristics of network structure whereas using OLS, the typical method for non-spatial data, tends to exclude spatial effects of spatial data. In this study, we analyzed land values focusing on the revised accessibility variables and the analytical technique that can include spatial effects. First, we adopted space syntax theory in order to consider not simple shortest distances along the streets but distances based on street network structure. Second, we compared OLS with GWR that includes spatial effects. Third, we used different size grid-cells for the spatial units considering MAUP theory and applied them to Gangnam-gu area. Each cell was analyzed for overall influence of independent variables using OLS, and coefficients were presented by GWR which enables local analysis and visualization. As a result, we found that suggested accessibility variables have a meaningful effects for land value analyses, and we were able to verify that GWR produces improved results compared to OLS. Also, we observed that the resulting values vary depending on the sizes of spatial units.

• Spatial Information Research
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• v.23 no.2
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• pp.83-93
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• 2015

U-Services, which are offered from local governments based on their Ubiquitous City Plans, are only focused on facility and urban management services. Also Citizen oriented U-service is only planned. This study's purpose is to propose the implication for provide of the Citizen oriented U-service comparing with U-Service plan of 'Ubiquitous City Comprehensive Plan' and 'Ubiquitous City Plan' through a network text analysis and word frequency analysis. It was calculated a important keyword that was extracted the service plan contents of the 'Ubiquitous City Comprehensive Plan' and 'Ubiquitous City Plan' of the four local governments. The network text analysis and keyword frequency analysis was performed through derived keyword. Based on the analysis results, awareness of the citizens can be expected to increase about U-City by activating a excavation of Citizen oriented U-service in a variety of sector through additional services and policy of financial support in the next Ubiquitous City Comprehensive Plan.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.10
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• pp.3668-3684
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• 2021

Video action recognition is widely used in video surveillance, behavior detection, human-computer interaction, medically assisted diagnosis and motion analysis. However, video action recognition can be disturbed by many factors, such as background, illumination and so on. Two-stream convolutional neural network uses the video spatial and temporal models to train separately, and performs fusion at the output end. The multi segment Two-Stream convolutional neural network model trains temporal and spatial information from the video to extract their feature and fuse them, then determine the category of video action. Google Xception model and the transfer learning is adopted in this paper, and the Xception model which trained on ImageNet is used as the initial weight. It greatly overcomes the problem of model underfitting caused by insufficient video behavior dataset, and it can effectively reduce the influence of various factors in the video. This way also greatly improves the accuracy and reduces the training time. What's more, to make up for the shortage of dataset, the kinetics400 dataset was used for pre-training, which greatly improved the accuracy of the model. In this applied research, through continuous efforts, the expected goal is basically achieved, and according to the study and research, the design of the original dual-flow model is improved.

• Journal of Korean Association for Spatial Structures
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• v.21 no.1
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• pp.79-86
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• 2021

Control performance of a smart tuned mass damper (TMD) mainly depends on control algorithms. A lot of control strategies have been proposed for semi-active control devices. Recently, machine learning begins to be applied to development of vibration control algorithm. In this study, a reinforcement learning among machine learning techniques was employed to develop a semi-active control algorithm for a smart TMD. The smart TMD was composed of magnetorheological damper in this study. For this purpose, an 11-story building structure with a smart TMD was selected to construct a reinforcement learning environment. A time history analysis of the example structure subject to earthquake excitation was conducted in the reinforcement learning procedure. Deep Q-network (DQN) among various reinforcement learning algorithms was used to make a learning agent. The command voltage sent to the MR damper is determined by the action produced by the DQN. Parametric studies on hyper-parameters of DQN were performed by numerical simulations. After appropriate training iteration of the DQN model with proper hyper-parameters, the DQN model for control of seismic responses of the example structure with smart TMD was developed. The developed DQN model can effectively control smart TMD to reduce seismic responses of the example structure.

• Journal of Korea Spatial Information System Society
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• v.2 no.2 s.4
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• pp.75-84
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• 2000

GIS has been building for various application fields with the aids of NGIS project, especially numerous municipal governments are building a UIS in the level of local governments' informatization. Although there are some difference between municipal governments' business, still many things are in common. So far, individual municipal governments have developed a UIS for their own use, which lead to duplicated development of the UIS. The component technology has been introduced to remove such duplicated efforts and it enabled maximizing the reusablilty of the UIS already developed. This paper proposes a component design for network analysis of the drinking water to calculate the amount of flow and the head loss. This component design provides the initial water amount to estimate the amount of the network flow and the head loss, thereby supports the decision making such as installation or extension of the pipe network. The process of the component design accompanies the business reengineering to support the standardized business work flow. Also, the design of the network analysis component uses the algorithms induced with UML specification. Based on the component design, the component development has been progressing and the network analysis system would be followed. In the near future, another component to integrate the network analysis and the business related to the drinking water needs to be developed.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.185-194
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• 2008

When forecasting demand for a new road, a select link analysis is usually used to understand the OD pairs that send trips along paths that use the selected link (i.e., the new road). These OD pairs and their associated volumes are listed in a select link analysis. However, there is no research about other methods to obtain these results, so experts are almost always dependent on select link analysis results to obtain these results. The purpose of this study is to propose a model with a different approach from select link analysis to obtain the previously mentioned results. Time and spatial characteristics of networks are used in this new approach. Select link analysis results are used as a comparison index for the results by the proposed model. Also, two case studies (interzonal trips and intracity trips) are performed to validate the significance of the model. Consequently, a correlation coefficient between the results by the proposed model and the comparison index shows high significance: 0.82.

• Korean Journal of Acupuncture
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• v.29 no.3
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• pp.431-440
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• 2012

Objectives : Recently, network science is very popular topic in various scientific fields and many studies have reported that it gives meaningful results on studying characteristics of a complex system. In this study, based on network theory, we made acupoints network using data of combined acupoints which appeared at "Beijiqianjinyaofang". We focused to find out the distinctive roles of remote and local combinations on the network. Furthermore, we aimed to identify the possibility of numerical and quantitative application to acupuncture researches. Methods : Based on examples of combined acupoints in "Beijiqianjinyaofang", the network consisted of 291 nodes and 2,431 links. The spatial distances between combined acupoints were calculated by the human dummy model. We removed the links step by step for the three cases - remote, local, and random cases, and observed the characteristic changes by calculating path lengths, similarity indices, and clustering coefficients. Also cluster analysis was carried out. Results : The network had a small number of remote links, and a large number of local links. These two links had the distinct characteristics. Whereas the local links formed a cluster of nearby nodes, remote links played a role to increase the correlation between the clusters. Conclusions : These results suggest that acupoints network increases the connectivity between the distal part and the trunk of human body, and enables various combinations of the acupoints. This finding conclusively showed that mechanism of combined acupoints could be interpreted meaningfully by applying network theory in acupuncture researches.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.3
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• pp.58-72
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• 2021

In July 2021, UNCTAD classified Korea as a developed country. After the Korean War in the 1950s, economic development was promoted despite difficult conditions, resulting in epoch-making national growth. However, in order to respond to the rapidly changing global economy, it is necessary to continuously study the domestic industrial ecosystem and prepare strategies for continuous change and growth. This study analyzed the industrial ecosystem of the automobile industry where it is possible to obtain transaction data between companies by applying complexity spatial network analysis. For data, 295 corporate data(node data) and 607 transaction data (link data) were used. As a result of checking the spatial distribution by geocoding the address of the company, the automobile industry-related companies were concentrated in the Seoul metropolitan area and the Southeastern(Dongnam) region. The node importance was measured through degree centrality, betweenness centrality, closeness centrality, and eigenvector centrality, and the network structure was confirmed by identifying density, distance, community detection, and assortativity and disassortivity. As a result, among the automakers, Hyundai Motor, Kia Motors, and GM Korea were included in the top 15 in 4 indicators of node centrality. In terms of company location, companies located in the Seoul metropolitan area were included in the top 15. In terms of company size, most of the large companies with more than 1,000 employees were included in the top 15 for degree centrality and betweenness centrality. Regarding closeness centrality and eigenvector centrality, most of the companies with 500 or less employees were included in the top 15, except for automakers. In the structure of the network, the density was 0.01390522 and the average distance was 3.422481. As a result of community detection using the fast greedy algorithm, 11 communities were finally derived.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.1
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• pp.24-34
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• 2014

To understand urban space and make appropriate plans, the integrative analyses considering road and land use simultaneously are required. In addition, studies that involve both horizontal and vertical spaces must be taken into consideration. Therefore, the purpose of this study is to conduct a classification analysis of road network-based land use considering spatial structure. The methods of this study were as follows; first, a space syntax theory considering the structure of road network was introduced for roads. For land use, to consider both horizontal and vertical development densities of residential and commercial buildings were used. And the explanatory power of three variables-Euclidean distance, global integration and length-reflected global integration-were compared. Third, based on road as an appropriate variable, modified-IPA was conducted with land use and the results were categorized into four areas. The proposed method was applied to Gangnam-gu, a CBD area in Seoul, and results were analyzed and visualized using GIS.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.397-406
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• 2013

Wetland conservation plan has been established to protect ecologically important wetlands based on vegetation integrity, spatial distribution of endangered species, but recently more demands are concentrated on the landscape ecological approaches such as topological relationship, neighboring area, spatial arrangements between wetlands at the broad scale. Landscape ecological analysis and graph theory are conducted to identify spatial characteristics related to core nodes and weak links of wetland networks in Nakdong basin. Regular planar model, which is selected for wetland networks, is applied in the Nakdong basin. The analysis indicates that 5 regional groups and 4 core wetlands are extracted with 15km threshold distance. The IIC and PC values based on the binary and probability models suggest that the wetland group C composed of main stream of Nakdong river and Geumho river is the most important area for wetland network. Wetland conservation plan, restoration projected of damaged and weak links between wetlands should be proposed through evaluating the node, links, and networks from wetlands at the local to the regional scale in Nakdong basin.