• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.149-155
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• 2003

This paper generally relates to the field of wireless local area networks(WLANs), and more particularly, to AP selection and association methods for the performance of a station. In these days, IEEE 802.11 Wireless LAN network is widely deployed and used as an emerging service to connect high-speed Internet in the public wireless environment. But, if there are many users in hot spot area, they suffer a severe decrease of performance. Thus it needs an association and access control mechanism especially when it is used in the public environment. In this paper, we suggest a selection and association method using Beacon or Probe Response frames based IEEE 802.11. Station selects AP using the information of the capacity area in a Beacon or a Probe Response frame. According to the present paper, an association method for a public WLAN service, which includes a WLAN user terminal and an AP for relaying WLAN communications to and from the user terminal, includes the steps of the user terminal asking the AP's states for access to a radio channel; and the station selects and associates with the AP. According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.

• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.645-652
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• 2008

The interest on the marine leisure sports is rapidly increasing with the advent of the five-day week and with increments of GNP. The self-governing bodies are trying to drag large investments into the marine leisures industry through international exhibitions and yacht rallies. Unfortunately, the demands in the domestic area don't increase differently from those demand patterns in the advanced countries. In this study, several suggestions for vitalizations on the marine leisure industry are made after surveying the recognition degree of the domestic people on the marine leisures and the current states of their spending on the marine leisures. As results, it has been shown that the policies based upon negative factors coming from negative understandings on the leisure activities should be largely revised. Further, it seems that the policies for the preparations of the laws and the regulations for the marine leisures as well as for the R&D policies should be taken systematically so that the infra structures are constructed while improving the negative understandings on the leisures. The fundamental databases investigated in this study will help the policy makers and the investors reduce the risks of the policy and the investments in the field of marine leisure sports.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.920-929
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• 2004

Nowadays, wireless packet data services are provided over cdma2000 1x/1xEV-DO mobile communication network and Portable Internet are being standardized for users demanding higher data rate services. Portable Internet can provide high data rate services, but its service coverage is relatively small. If Portable Internet may be integrated with cdma2000 mobile networks, users are able to choose the best service according to service areas and get seamless services while they are moving around. At the same time, it is cost-effective for operators to construct and maintain the integrated network. For the purpose of effectively integrating Portable Internet into cdma2000 networks, we propose an integration scheme including network architecture, protocol architecture, functions in network elements, interfaces between them, and call-flow procedures. The integration scheme proposed in this paper adopts a tightly-coupled architecture for unified authentication/accounting and seamless services. In addition, the scheme can be implemented without modifying the existing cdma2000 mobile communication networks. It is also simple to develop the dual-mode mobile station. Through the simulation results based on the performance model for handoffs between cdma2000 and Portable Internet, it has teen validated that the proposed scheme diminishes packet losses compared with the loosely-coupled architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1040-1047
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• 2015

This study is investigated for M2M Communication Network Standard based on 3GPP. The environment of M2M communication, we can predict the new mobile service that gathering, handling, controlling, transferring of the data for Intelligence, so that we can consider new direction for a lot of subject of study development issue. This study is shown three types of M2M network structure and four types of use cases on 3GPP International Standard. In Addition, we can introduce the future M2M communication network model, it can be propagate the industry and academic cooperation with 3GPP standards. The suggestion develops multiple applications and multiple devices for industry and academic. With the deployment of network provider, this environment support our current communication market that the standard devices of M2M network and service requirement. We are suggest this study for grasp the initial market with the intellectual property right (IPR) based on International Standards. In the future, we wish the success that grap the initial market or initial academic study with helpful issue.

• Korean Security Journal
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• no.34
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• pp.185-207
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• 2013

Nowadays, national criminal policy focuses on "specialization", "advancement", and "choice and concentration" to enhance the efficiency and effectiveness of public peace services. Consequently, the space that a nation manages diminishes and there appears vacant space of security. For that reason, in most developed countries including South Korea, there has been a significant expansion in the size and role of Private Security(PS). From this point of view, the Japanese government has adopted the PFI(Private Finance Initiative) system in private prisons. These cases clearly show the role and significance of "PS". By applying know-how of the private sector, these PFI prisons make efficient use of installation by the united efforts of government and people. Criteria such as solution for risk baring, regional coexistence, preservation of public security, response management and operating skills are considered important particularly in Kitsuregawa and Harima prisons. Thus, this study examines the implications and applicability for the expansion of PS in South Korea.

• Journal of Korea Water Resources Association
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• v.44 no.9
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• pp.765-776
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• 2011

Flood discharge capacity in a dam downstream reach has been decreased after dam construction because of the river cross section reduction impacted by farm lands, sand-bars and parking lots, etc. in river flood plains. Those obstacles being in the river inside areas have caused negative influences to the dam operation policy. Therefore, the dam downstream river improvement work associated with the dam operation improvement plan is under construction for removing reduction factors on the dam effective storage, assuring flood safety in the dam downstream river and incrementing dam operation benefits. But the project has issued some problems such as project feasibility, economic evaluation, cost allocation and benefit share, etc. Since a dam enterpriser has not committed such kind of project before, it is necessary to set up an objective analysis process and a quantitative financial valuation. This study examines the measurable economic benefits and the cost allocation of the project for the fairness between benefit owners (central government and water electricity enterprisers). As a result, the total economic benefit from 3 dams (Imha, Daechung and Youngdam Dam) accounts for 14.41 Billion Won/year. The financial valuation of K-water as a project enterpriser is approximately estimated at 40% of the total value and the government is 60%.

• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.1-10
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• 2014

This study discusses crossmedia storytelling strategy plans by utilizing N-Screen service. It conceptualizes the definitions of N-Screen service in terms of smart contents. Related previous researches are extensively introduced to clarify how N-Screen service would be different from previous similar services. Most domestic N-Screen services have adopted OSMU method which provides the same contents from various platforms. It is, however, centered only on a development company's one-sided service and neglects to reflect the characteristics of a media or platform. In this light of gap, this study introduces ASMD method which is based on cross media. By providing right contents services according to types of smart media and enhancing a user's participation, users can enjoy a variety of entertainment and rich contents experiences and development companies can expect better promotion effects and an increase in sales. Finally, this study argues for strategies of crossmedia storytelling by using ASMD method, based on both domestic and overseas examples of contents development with crossmedia. As more and more diverse forms of media and platform would be introduced in the future, new strategies and perspectives would be imperative to cope with new environment. Conventional OSMU method bears inherent limitations to cover the range of N-Screen application. This study discusses the ways to mitigate the limitations by proposing ASMD method with crossmedia.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.635-641
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• 2019

Domestic southwest offshore wind farms have problems such as the reduction in fishing rights by prohibiting vessel traffic, which delays their development. As such, there is a need to develop offshore windfarms in Europe to permit the passage of vessels and fishing operations in specific offshore windfarm areas. In this study, we used the environmental stress (ES model) and the IALA Waterway Risk Assessment Program (IWRAP) to determine the ratio of risk to the route type (cross pattern, grid pattern) and traffic volume (present, 3 times, 5 times and 10 times) to derive the risk factors of specific vessels for offshore windfarms. As a result, ship operators' risk related to offshore windfarms did not rise in both route types and there was no significant difference in the annual probability of collision in the present traffic volume. In conditions that increased traffic volume by 3 times, 5 times and 10 times, the risk ratio increased as ship operator risk and collision probability increased at the crossing points. Furthermore, when the traffic volume of the ship increased, the risk could be more effectively distributed in the grid route compared to the cross route. The results of this study are expected to apply to the operation type, route operation method, safety measures, etc. in offshore wind farms.

• International Commerce and Information Review
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• v.16 no.1
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• pp.227-245
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• 2014

It was ten yeas ago that Bolero Bill of Lading was been introduced on the base of efforts of UN and CMI to solve the crisis of Bill of Lading, but Electronic Bill of Lading is not utilized in practice owing to the problems to be settled. Bolero Bill of Lading is not in widespread use owing to absence of collaboration model between Bolero and e-Trade service providers in each nation in the early stage. In the situation that Bolero Bill of Lading is not utilized in practice, Korean Commercial Law regulates the designation of the registration authority of Electronic Bill of Lading. Therefore, the Minister of Justice designated KTNET as Registration Authority of Electronic Bill of Lading and KTNET opened the e-B/L Korea (www.eblkorea.or.kr) to provide the Electronic Bill of Lading service to domestic trade community. But there is many problems in supplying the Electronic Bill of Lading service by the e-B/L Korea in compared with Bolero Bill of Lading. These problems are related with the characteristics of designation of Registration authority of Electronic Bill of Lading. Therefore the purpose of this paper is to contribute to the activation of Electronic Bill of Lading domestically by studying the designation of Registration authority of Electronic Bill of Lading in Korea and finding the characteristics of the designation and the issues and problems regarding the characteristics.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.2
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• pp.54-68
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• 2015

The advantage of electric taxies is that people who are not familiar with electric vehicle(EV) can have easily experience to ride EV. So, EV taxi would be a reasonable strategy for triggering EV market expansion. However, the EV taxi can be adopted by taxi companies with financial benefits. Therefore the feasibility study should be required by analyzing the cost with the points of view of the taxi company. In this study we suggested the methodology for feasibility study of the EV taxi based on the real taxi data and presented political implication. According to the study result, EV taxies could have economic value under the specific conditions such that the government subsidy is added to the purchase price of the vehicle. Also, the charging time should be used as drivers' rest time or mealtime in order not to consider the loss cost. We suggest that the new feasibility study which compares an EV taxi with other alternative vehicles such as PHEV or with an old EV taxi is needed as the future works.