• Korean Management Science Review
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• v.22 no.2
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• pp.35-49
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• 2005

When new services are introduced, interaction among existing and new services has to be considered. The interaction can be characterized by the substitution or complementary effect among services. This paper analyzes how the interaction among services affects the customers' subscription decision in telecommunication services industry. Based on a face-to-face in-depth survey from a sample of 1,200 respondents, a new wireless internet access service or WiBro is analyzed to identify the substitution/complementary effect in relation to the existing other telecommunication services. Additionally, the important factors explaining both customers' subscription and substitution decisions are identified. The analysis results indicate that males and students are more likely to subscribe WIBro service. Interestingly, family size positively affects the subscription decision. However, heavy users of on-line game are reluctant to subscribe WiBro service. Among the potential WiBro subscribers, the customers who are less satisfied with the existing fixed line broadband internet access service are more likely to stop subscribing the fixed line service, which implies substitution by a new service. We believe that the consideration of the interactions among services is essential to devise a winning strategy for the new services in the highly uncertain telecommunications business environment.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.507-514
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• 2019

Federal communications commissions (FCC) has announced the first set of rules for 3.5 GHz (3,550 - 3,700 MHz) band used Navy radar and fixed satellite service (FSS) earth stations as primary service to sharing for citizen broadband radio service (CBRS) enable development of relatively low powered network technologies like small cells. Since CBRS sharing technique based on the 3-tiered spectrum access system (SAS) is able to protect the higher tiered users from harmful interference from lower tiered users, it has been considered actively to be introduced in Korea. However, 3.5 GHz band had been already allocated to the 5G services in Korea, the sharing studies have been carried out for 3,700 - 5,000 MHz, As the result, the 3.8 GHz (3,800 - 3,900 MHz) band used for only FSS system is able to be sharing, and an introduction of CBRS has been proposed in Korea by analyzing the interference to the FSS earth stations.

• East Asian Economic Review
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• v.28 no.2
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• pp.143-174
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• 2024

This paper empirically examines the relationship between outward foreign direct investment (OFDI) of Korean manufacturing firms and the servicification of domestic employment using a firm-level panel data. In this study, considering the issue of low productivity in the Korean service sector, we categorize service employment into core and non-core services and investigate their relationship with OFDI using the firm-fixed effects model. The empirical results show that the share of core service employment exhibits a positive correlation with the extensive OFDI. On the other hand, the share of non-core service employment, which is expected to generate relatively low value-added, does not show a significant relationship with the extensive OFDI. When we divide the samples based on host countries and the type of subsidiaries, the impact on servicification varies depending on the technological capabilities of host countries and their participation in global value chains. Our study suggests that Korean manufacturing firm's internationalization strategies may facilitate a transition from labor-intensive employment, like the cases in advanced countries, to technology-intensive employment through OFDI and other means.

• YAKHAK HOEJI
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• v.57 no.3
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• pp.213-218
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• 2013

This study examines factors associated with fixed budgets for pharmaceuticals and clawback system for pharmaceutical industry in European countries. We used information from a survey held in 2005~2006 by Austrian Health Institute. Several information including pharmaceutical pricing policies, marketing conditions for pharmaceutical industry and patient' choice of drugs was collected. Five out of twenty five countries in EU were considered as countries with fixed budgets for pharmaceuticals and remaining 20 countries were considered as countries without fixed budget system. Comparisons were made for each information. Countries with fixed budgets for pharmaceuticals were more likely to have internal (or external) reference pricing system and other pricing mechanisms. In addition, they were more likely to permit pharmaceutical industry to be engaged in public advertising and information provision towards patients. They guaranteed patient participation in drug choice decisions. The countries with fixed budgets for pharmaceuticals were more likely to have conditions that enable the fixed budget system to work better compared to those without fixed budget system. Therefore, the study results imply that we need to check whether we have similar conditions to the countries that already have fixed budgets for pharmaceuticals when we want to introduce fixed budget mechanism for pharmaceuticals in Korea in the future.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1033-1036
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• 1999

In storage technology it is desirable to have greater storage capacity at lower costs. Data compression addresses these demands by reducing the amount of data that must be stored to a given size of media, thus lowering the cost of that storage device. In data compressions it is desirable to have faster transfer rates at lower costs. Data compression addresses these demands by reducing the amounts of data that must be transferred over a media with a fixed bandwidth, thus reducing the connection the. Data compression also reduces the media bandwidth required to transfer a fixed amount of data with a fixed quality of service, thus reducing the costs on this service.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.85-90
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• 2015

Work environments within the firm with a concept of mobile office is growing divided into two sections. It's Wi-Fi FMC(Fixed Mobile Convergence) field Which are implemented in a telephone service available from existing fixed-line service in the center of the smart phones and the EMS(Enterprise Mobility Service) field to make people will be able to handle PC the center of the information system within an enterprise using a smart phone instead of terminal facility connects to a system in the workplace and external. This paper developed FMC controller to allow execution IMS(IP Multi-Media Subsystem) services to complement the issues of the FMC corporation, telephony service associated. The controller includes FMC automatic enrollment services, voice quality enhancement of the mobile phone, anywhere within the firm on his mobile phone calls can provide mobility and is also implemented FMC LCR function that use status information from mobile soft-phone within the IP-PBX.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.130-139
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• 2014

Due to the unpredictable nature of channel availability, carrying delay-sensitive traffic in cognitive radio networks (CRNs) is very challenging. Spectrum leasing of radio resources has been proposed in the so called coordinated CRNs to improve the quality of service (QoS) experienced by secondary users (SUs). In this paper, the performance of coordinated CRNs under fixed-rate with hard-delay-constraints traffic is analyzed. For the adequate and fair performance comparison, call admission control strategies with fractional channel reservation to prioritize ongoing secondary calls over new ones are considered. Maximum Erlang capacity is obtained by optimizing the number of reserved channels. Numerical results reveal that system performance strongly depends on the value of the mean secondary service time relative to the mean primary service time. Additionally, numerical results show that, in CRNs without spectrum leasing, there exists a critical utilization factor of the primary resources from which it is not longer possible to guarantee the required QoS of SUs and, therefore, services with hard delay constraints cannot be even supported in CRNs. Thus, spectrum leasing can be essential for CRN operators to provide the QoS demanded by fixed-rate applications with hard delay constraints. Finally, the cost per capacity Erlang as function of both the utilization factor of the primary resources and the maximum allowed number of simultaneously rented channels is evaluated.

• Journal of Communications and Networks
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• v.9 no.2
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• pp.159-166
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• 2007

In this paper, we propose an efficient and robust interference mitigation technique based on a nullsteering multi-user multiple-input multiple-output (MU-MIMO) spatial division multiple access (SDMA) scheme for frequency sharing between IMT-advanced and fixed satellite service (FSS) in the 3400-4200 and 4500-4800 MHz bands. In the proposed scheme, the pre-existing precoding matrix for SDMA unitary precoded (UPC) MIMO proposed by the authors is modified to construct nulls in the spatial spectrum corresponding to the direction angles of the victim FSS earth station (ES). Furthermore, a numerical formula to calculate the power of the interference signal received at the FSS ES when IMT-Advanced base stations (BS) are operated with the interference mitigation technique is presented. This formula can be derived in closed form and is simply implemented with the help of simulation, resulting in significantly reduced time to obtain the solution. Finally, the frequency sharing results are analyzed in the co-channel and adjacent channel with respect to minimum separation distance and direction of FSS earth station (DOE). Simulation results indicate that the proposed mitigation scheme is highly efficient in terms of reducing the separation distance as well as robust against DOE estimation errors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.6
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• pp.273-286
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• 1985

Nowadays, the satellite communication systems provide worldwide or international service through organizations such as INTELSAT and INMARSAT, and the satellite communication technology has brought remarkable changes in the maritime mobile service as well as the fixed service on land. In our country, the international fixed satellite service via INTELSAT is no means inferior to the advanced countries, but to the contrary, we feel ashamed to admit that the facilities and technologies of our maritime satellite service via INMARSAT system donot keep abreast with the development pace of the world. This paper describes first the historical review of the development of satellite communication system is the world, then analyses the problems to bring the systems into wider use as early as possible, and filnally, I will make the following suggestions for the promotive direction on the INMARSAT systems. 1. Estabilishment of the earth stations at sea and on land. 2. Standardization of the qualification of the principal communicator on board. 3. Promotion of the international cooperation for the maritime mobile satellite service. 4. Establishment of the research institute on the INMARSAT systems.

• The Korean Journal of Health Service Management
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• v.11 no.3
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• pp.1-11
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• 2017

Objectives : The purpose of this study was to analyze factors affecting the performance of public hospitals in South Korea. Methods : We collected management performance data from 2013 to 2015 from income statements, balance sheets, and annual reports from 32 local public hospitals. The dependent variable used was profitability, which included operating margin, return on assets and net profit to gross revenues. The independent variables were general characteristics, liquidity, stability, and activity. Results : Patient revenues, total assets, and total capital had increased steadily but patient expenses had increased to a greater extent. Operating profit, and net profit were consistently in deficits and the management status of local public hospitals had recently been in difficulty. The debt ratio, quick ratio, ratio of fixed liability and fixed assets turnover rate have a significant positive(+) effect on performance in the years 2013-2015. Conclusions : We suggest management strategies for these hospitals based on the results analyzed.