• ETRI Journal
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• v.26 no.6
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• pp.665-668
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• 2004

The introduction of a mobile virtual network operator (MVNO) system is expected to increase consumer benefits, boost competition in the mobile market, utilize idle bandwidth, and expedite mobile-fixed line convergence and growth in the mobile Internet market. This research endeavors to study the optimal access charge for an MVNO system, which is expected to be introduced to the Korean mobile communications market. We found that the optimal access charge is higher in the interdependent model than in the independent model if demand for mobile phone service is based on a substitution relationship. We also found that the optimal access charge is higher than the marginal cost.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.3
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• pp.9-18
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• 2008

Mobile devices do not need the fixed network infrastructure in ad-hoc network, these devices communicate each other through the distributed control. Accordingly, mobile devices can discover several services using dynamic searching method and provide safely public ownership of these services. Ad-hoc network needs the distributed control and topology of dynamic network because the limited power for processing and network communication. This paper is devoted to provide the secure protocol that provides efficient services discovery using SDP(Service Discovery Protocol) and considers the security requirements. Proposed protocol provides the distributed control based on PKI without central server, the discovery of trusted service, secure telecommunication, the identification among mobile devices, and service access control by user authority.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1350-1354
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• 2014

Although there were many activities to provide FMC (Fixed Mobile Convergence) service by several foreign countries such as United States, FMC service could not make a good success for a number of reasons for example, customers indifference and lack of needs. On the other hand, recently FMC is showing its good progress at B2B market in foreign government such as in Germany and US satisfying e-government and BYOD (Bring Your Own Device) needs. This paper studies FMC service of foreign countries and as a result makes a analysis presenting issues for Korean e-government service. Also, we make several suggestions to energize FMC service success.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.358-361
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• 2003

As the information and communication technology has been developed, demand for internet and multimedia is increased and customer's needs becomes diverse. Therefore, the convergence of fixed and mobile networks has emerged. Fixed - Mobile Convergence (FMC) service means that it provides users with one type of services from network access to billing regardless of networks and terminal. FMC service is expected to provide an advanced value with both networks providers and users. Wireless local area network (WLAN) and 2.3㎓ HPi are promising services that will generate enormous demands among FMC services. For that reason, this paper investigates the trend of WLAN and HPi in Korea and abroad and suggests future deployment based on reviewing the literature.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.428-434
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• 2017

In recent years, owing to the growing user demand for the two-way internet service based on the mobile global broadband communications, a new type of satellite terminal has been developed, known as ESIM(Earth Station in Motion). This service was required by Resolution 158(WRC-15) to study on the coexistence with the co-primary FS(Fixed Service) in 27.5-29.5 GHz as a FSS(Fixed Satellite Service) uplink. In this paper, the average received power on ESIM within -10 dB of beam width of FS and its outage probability was analyzed theoretically and also simulated to account for the azimuth angle with uniform distribution. From the results, it can be concluded that this theoretical analysis is very useful to analyze the interference from ESIM into FS based on the statistical and probabilistic method. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the inclination angle of moving path, the operation hours, and the speed of ESIM to protect the co-primary FS.

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.155-161
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• 2020

The fifth generation (5G) is a state-of-the-art mobile communication access technology that uses sub 6 GHz bands and mmWave. Presently, the 5G network is partially deployed along with 4G in areas with dense traffic. In the future, the demand for the 5G bandwidth may increase. Thus, it is necessary to study the coexistence between the 5G and radio systems using adjacent or same channels to eliminate the interference between radio systems and efficiently utilize the frequency. This paper analyzed the impact of 5G new radio downlink on the fixed-satellite service earth station operating at the co-channel and adjacent channel in the upper 3.7 GHz band using the Spectrum Engineering Advanced Monte Carlo Analysis Tool, which is based on the Monte Carlo method. The results of this paper can be utilized for planning the frequency allocation of 5G networks; they can also be used as a guideline for deploying 5G base stations around a fixed-satellite service earth station.

• Journal of Navigation and Port Research
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• v.35 no.2
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• pp.159-165
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• 2011

The aim of paper is to calculate the optimized size of Mobile Harbor(MH) which would be operated in South Korea coast area. MH is the combined entity which has the function of both ship and container port. In estimating the optimized size, the total cost concept is applied to the different size of MH. Trade-off factors for calculating total cost are MH cost and the over-capacity lost cost. The factors for MH cost estimation are the cargo demand, distance from origin to destination, voyage route and MH's fixed and variable cost in both sailing and port. The other cost is the over-capacity lost cost which is occurred from dead space in case of oversize compared with a voyage demand. The alternatives for the least cost are 250TEU, 500TEU, 750TEU and 1,000TEU sized vessel. The result of research is that 250TEU sized vessel is optimized in a South Korea costal service. If the coastal area be separated in terms of voyage distance or the specific area in considering trade, the optimized size is changed depending upon distance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.259-264
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• 2010

In this paper, for supporting more variable services than typical DSRC, brand call service, truck and an official vehicle services, etc. using location information and mobile communication network could be adapted. emergence helping information providing, multimedia service that are wireless internet, movies and games, are increasingly needed for competible wireless car mobile terminal. Those needs would make a development a wireless telemetries system based on WiBro interface in ubiquitous vehicle environment. We analysis the proposed telematics mobile terminal using simulation which is concerned about fixed bandwidth and dynamic bandwidth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3275-3279
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• 2011

The matter of the calculation of the mutual access fee has become one of the hottest issues among service providers and attracted concerns from concerned regulatory authorities. It is essential to conclude a rational and systematic procedure for interconnection costs and charge between fixed and mobile networks. In this paper, I proposed the conversion factor scheme between circuit switched voice and packet switched data service in the domestic CDMA mobile system based on analysis of the rational GSM allocation method of common cost.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.234-242
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• 2010

The demand on various broadcasting services has been greatly increasing in the area of mobile communication. In IEEE802.16e standard and mobile WiMAX, the multicast broadcast service (MBS) uses shared downlink channel for efficiently supporting a number of users. In this paper we propose a dynamic modulation and coding scheme with relay network to enhance the performance of MBS. The proposed approach employs the adaptive modulation and coding scheme for both the base station and relay station to achieve consistently high throughput. The result of computer simulation with NS-2 shows that the throughput and transmission time are significantly improved by using the proposed approach compared to the existing schemes having a fixed modulation level for the RSs.