• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.117-124
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• 2010

Most of the rivers which exist in nature are not a single river but the network that is composed of several branches and mainstreams. The river network are more complicated than other sigle rivers and streams. Therefore the hydraulic characteristics are sensitively changed by reduction and expansion of the width in the confluence or the variation of the flux. In this paper, the hydraulic characteristics were calculated by the change of the width and length in the confluence and the hydraulic model test. The deposit of confluence emerged at the left bank, right bank and the stagnation sector. As the total flow in the branch have increased, stagnation of the left bank and right bank have decreased. When the width of the downstream have been get smaller from 3 m to 2 m, the deposit of the left bank and right bank and stagnation sector have decreased. But as the eddy flow in the center of the confluence is occurred, the erosion has been increased. The result of this paper can be used as a basic data of water management around the junction and for maintenance on the ground of development of the river.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.99-106
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• 2004

This paper presents some comparisons between Cournot-Nash and Stackelberg game in bi-level program, composed of both upper level program and lower level one. The upper level can be formulated to optimize a specific objective function, while the lower formulated to express travelers' behavior patterns corresponding to the design parameter of upper level problem. This kind of hi-level program is to determine a design parameter, which leads the road network to an optimal state. Bi-level program includes traffic signal control, traffic information provision, congestion charge and new transportation mode introduction as well as road expansion. From the view point of game theory, many existing algorithms for bi-level program such as IOA (Iterative Optimization Assignment) or IEA (Iterative Estimation Assignment) belong to Cournot-Nash game. But sensitivity-based algorithms belongs to Stackelberg one because they consider the reaction of the lower level program. These two game models would be compared by using an example network and show some results that there is no superiority between the models in deterministic case, but in stochastic case Stackelberg approach is better than that of Cournot-Nash one as we expect.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.139-145
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• 2016

Dumbbell is the most basic topology that can be used in almost all kind of network experiment within it or just by little expansion. While Transmission Control Protocol TCP is the basic protocol that is used for the connectivity among networks and stations. TCP major and basic goal is to provide path and services to different applications for communication. For that reason TCP has to transfer a lot of data through a communication medium that cause serious congestion problem. To calculate the congestion problem, different kind of pre-cure solutions are developer which are Loss Based Variant and Delay Based Variant. While LBV keep track of the data that is going to be passed through TCP protocol, if the data packets start dropping that means congestion occurrence which notify as a symptom, TCP CUBIC use LBV for notifying the loss. Similarly the DBV work with the acknowledgment procedure that is used in when data ACK get late with respect to its set data rate time, TCP COMPOUND/VAGAS are examples of DBV. Many algorithms have been purposed to control the congestion in different TCP variants but the loss of data packets did not completely controlled. In this paper, the congestion control algorithms are implemented and corresponding results are analyzed in Dumbbell topology, it is typically used to analyze the TCP traffic flows. Fairness of throughput is evaluated for different TCP variants using network simulator (NS-2).

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.209-215
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• 2018

The purpose of this study is to grasp the overall policy decision system of sex crime prevention policy and analyze the interaction and pattern of actors in policy formation process. This is a useful way to identify the causes and ways to improve the policy if the sex crime prevention policy fails. As a research method, we used a model of advocacy through case analysis and language network analysis. In the external environment, low reporting of sex offenses, technical improvement and supplement for preventive management, consciousness of victims of sexual crimes, amendment of legislation, and support of the president. The conflicts between the advocacy coalition opposed the strong regulation, the prevention of recidivism, the expansion of the range of objects to be worn, the temporary effect of the system and the retrospective of the bill. As a problem-solving strategy, it was confirmed that the opposing positions of pros and cons of lack of manpower and negligence of management through the extension of the system were acutely opposed. In the context of media reports, this tendency is more likely to be understood as the concern of prevention and management at the central government level to prevent sex crimes. Therefore, although the methods of prevention of sex crimes have been insufficient in the past, it is hoped that this study will be helpful in breaking the link of negative policy vicious cycle.

• Journal of Korean Society for Geospatial Information Science
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• v.5 no.2 s.10
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• pp.131-144
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• 1997

Traffic jam densified day by day is phenomenon to occur lack of the road capacity in comparison with traffic density, but lack of the road cannot be concluded by main cause of traffic ism. Because the central function of a city would be concentrated upon the downtown and traffic demand would not be evenly distributed by the classification of an hour. Therefore, this study based on the fact that each driver will select the route generating traffic delay very low when path choice from origin to destination in travel plan estimating the quality of passage could be maintained the speed he want will approach to a characteristic grasp of a road, traffic, driver changing every moment by traffic-demand of road increased as a geometrical series with analysis a classification of a street, a intersection along the path on traffic density and highway capacity analysis the path using GIS techniques about complex street network, also will get the path of actual optimum for traffic delay trend creating under various condition the classification per a hour, a day of week and an incident through network such as analysis for traffic generation zone adjacent about street, intersection, afterward will expect the result increasing efficiency of the road-use through a good distribution of traffic by optimum-path choice, accordingly will prepare the scientific, objective, appropriate basis to decide the reasonable time of a road-widen and expansion through section analysis along a rate of traffic volume vs. road capacity.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.24-32
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• 2015

The global success of PSY's Gangnam Style was mediated through combination of YouTube and SNS. PSY's success led into some communication scholars' consideration of new international circulation of Korean pop culture (Korean Trend 2.0). In terms of global circulation of pop culture, it is noticeable how users appropriate YouTube channel beyond mere watching music videos and mere international circulation of Korean pop culture. The mode of fan's activity and appropriation contributes to the expansion of the width and amplification of the volume of Korean popular culture as well. The circulation of pop culture was considered in the level of exchange of tangible commodities such as CD, DVD, and so on until the adoption of digital media and Internet. YouTube has brought new mode in which the international circulation of pop culture is mediated without exchange of tangible commodities but was amplified with the diffusion of network. This study grasps how the mode of users' appropriation contributes to international circulation of pop culture through case studies of some K-pop music videos and international K-pop fans' tribute activities. In terms of theoretical perspective, fandom studies will be examined. In terms of research method, the researcher adopts netnography, a participatory observation on network, to find the feature of fandom and its contribution to the international circulation of pop cultures.

• Journal of the Economic Geographical Society of Korea
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• v.3 no.2
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• pp.43-61
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• 2000

This study investigate the spatial characteristics and corporate networks of foreign business service firms in Korea. Specifically intrafirm and extrafirm organization of foreign firms are addressed utilizing the corporate network perspective. For this purpose, this study conducted questionnaire and interview surveys for the foreign firms. Parent-subsidiary relationships are focused on the mechanisms by which Transnational Corporations (TNCs) headquarters control and coordinate their foreign affiliates and subsidiaries in order to achieve investment purpose in Korea (overseas market expansion). But extrafirm networks of foreign business services firms in Korea do not appear to play an important role in regional development to date. A low proportion of foreign firms is engaged in academics-industry linkages, and a low number o( foreign firms is formally linked with government organizations, research institutes, and trade associations. To conclude, Foreign direct investment firms in business services in Korea are characteristics by globalized intrafirm networks and localized interfirm and extrafirm networks. It is understood that regional development can be vitalized when Korean local firms have close relationships with technologically advanced foreign firms in tacit knowledge capacity. Foreign firms are able to play an important role in the development of business services in Korea. This study suggests that regional foreign direct investment policy should be targeted towards the corporate networking with foreign firms and domestic firms and incrementation of the potential of foreign firms as a knowledge-intensive industry.

• The Journal of Small Business Innovation
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• v.21 no.1
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• pp.15-26
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• 2018

SMEs need a strategy to respond to rapid changes in the global business environment of the Fourth Industrial Revolution. In order to overcome such a business environment, SMEs must concentrate on the core competency. Because of the structural characteristics of SMEs, government support is very important, as it is difficult for SMEs to carry out the entire supply chain role. The support of GRIs is very important for ensuring competitiveness through technological innovation of SMEs. Recently, the construction of SMEs network for business expansion is demanded. SMEs can form networks to induce synergistic effects. In order to secure the competitiveness of SMEs by utilizing the advantages of mutually cooperating networks, the necessity of cooperation of SMEs is increasing. The government has proposed various support programs to support network cooperation. In this research, in order to derive an effective strategy of the SME support program, we analyzed the difference in necessity and satisfaction of the GRIs support program. We analyze the differences between government policies and perceptions for SMEs and to derive strategies for supporting SMEs in a systematic approach for the development of SMEs. In a situation where research to revitalize SMEs is insufficient, in consideration of the market demand of SMEs, we grasp the problems of the current system and try to guide improvement strategies. Also, we suggest policies that can derive and utilize support strategies for SMEs. From a long-term perspective, research related SMEs must be conducted and a sustainable support program for SMEs must be developed.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.249-254
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• 2019

According to the recent expansion of the network environment, the spread of smart devices is continuously increasing. With the spread of smart devices such as smart phones, smart pads and wearables, changes are taking place in smart technologies and IT convergence technologies. The development of smart technology is a key element of the 4th industrial technology. The Fourth Industrial Revolution expanded the new service-based industry by adding intelligence to residential, industrial and production environments using IT convergence and smart devices. Research on providing various services using smart technologies, such as smart home, smart factory, smart farm, and smart healthcare, is being conducted in variety. In particular, There is a sharp rise in smart homes due to the proliferation of IoT devices and the growth of sensor technology, control technology, applications, data management, and cloud services. Smart home services using smart technology provide residents with convenient, beneficial services and environments. Smart home service has complemented the existing home network service, but there still are flaws to be modified. In other words, the spread of smart devices, the development of service provider-oriented services, and the interlocking of services have limitations in providing services in consideration of user environment and user state. In order to solve this problem, this study proposes a smart home service system that considers the situation of the elderly.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.645-647
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• 2015

We have initiated a Very Long Baseline Interferometer (VLBI) monitoring project of 36 methanol maser sources at 6.7 GHz using the Japanese VLBI Network (JVN) and East-Asian VLBI Network (EAVN), starting in August 2010. The purpose of this project is to systematically reveal 3-dimensional (3-D) kine-matics of rotating disks around forming high-mass protostars. As an initial result, we present proper mo- tion detections for two methanol maser sources showing an elliptical spatial morphology, G 002.53+00.19 and G 006.79-00.25, which could be the best candidates associated with the disk. The detected proper motions indicate a simple rotation in G 002.53+00.19 and rotation with expansion in G 006.79-00.25, respectively, on the basis of disk model fits with rotating and expanding components. The expanding motions might be caused by the magnetic-centrifugal wind on the disk.