• Journal of Communications and Networks
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• 제9권3호
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• pp.319-329
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• 2007

This paper presents a price-based quality-of-service (QoS) control framework for two-class network services, in which circuit-switched and packet-switched services are defined as "premium service class" and "best-effort service class," respectively. Given the service model, a customer may decide to use the other class as a perfect or an imperfect substitute when he or she perceives the higher utility of the class. Given the framework, fixed-point problems are solved numerically to investigate how static pricing can be used to control the demand and the QoS of each class. The rationale behind this is as follows: For a network service provider to determine the optimal prices that maximize its total revenue, the interactions between the QoS-dependent demand and the demand-dependent QoS should be thoroughly analyzed. To test the robustness of the proposed model, simulations were performed with gradually increasing customer demands or network workloads. The simulation results show that even with substantial demands or workloads, self-adjustment mechanism of the model works and it is feasible to obtain fixed points in equilibrium. This paper also presents a numerical example of guaranteeing the QoS statistically in the short term-that is, through the implementation of pricing strategies.

• 한국위성정보통신학회논문지
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• 제10권3호
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• pp.137-142
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• 2015

본 논문에서는 Ku-대역에서 고정위성업무를 위한 주파수 신규 분배를 검토하는 WRC-15 의제에 대한 배경 및 연구 동향을 분석하고, 향후 국내 대응 방안을 고찰하였다. 위성 주파수는 전파규칙이 규정한 국제등록 절차에 따라 확보되는 자원이며, 주파수 자원은 한정된 천연자원으로 인식되어 각 국가들의 자원 선점을 위한 경쟁이 점점 심화되고 있다. 이러한 상황에서 WRC-15에서는 고정위성업무용으로 주파수 추가 분배를 검토하게 되는데, 기존 업무의 적절한 보호 및 향후 고정위성업무의 이용 계획을 고려하여 적절히 대응할 필요가 있다.

• Journal of information and communication convergence engineering
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• 제18권3호
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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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.465-468
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• 2000

The interference situation for the satellite networks using non-geostationary satellite orbit (NGSO) is more complicated than the situation between geostationary satellite orbit (GSO) networks because of the time varying orbital characteristics of NGSO systems. Most of frequency bands are allocated to fixed-satellite service and liked-service in co-primary basis. In this paper, the sharing criteria between NGSO/FSS systems and HDFS (High Density Fixed-Service) are examined.

• 한국항행학회논문지
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• 제20권6호
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• pp.503-510
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• 2016

최근 이동형 글로벌 광대역 통신 및 위성기반의 양방향 인터넷 서비스에 대한 수요가 증가함에 따라 ESIM (earth station in motion)이라는 새로운 형태의 위성 터미널이 개발되고 있다. 이 서비스는 ITU-R Resolution 158(WRC-15)에서 FSS 업링크에 27.5-29.5 GHz 대역사용을 고려하고 있어 동일대역에서 1순위 업무로 분배된 FS와의 간섭분석에 대한 연구가 요구되고 있다. 이에 본 논문에서는 ESIM이 기존의 FS(fixed service)에 미치는 간섭영향을 안테나의 포인팅 에러와 방위각을 고려하여 4 가지 시나리오에 대해 분석하였다. 그 결과 에러 초과확률 5% 및 10% 기준에서 앙각이 $20^{\circ}{\sim}40^{\circ}$에 따라 두 시스템간의 분리거리는 32~52 km 정도 요구되고 있다. 이에 분리거리를 최소화하면서 동일대역의 FS를 보호하기 위해서는 안테나 포인팅 에러뿐만 아니라 이동 터미널의 방위각을 제어할 수 있어야 한다.

• 대한치과보철학회지
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• 제61권1호
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• pp.63-72
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• 2023

완전 무치악에서 전악 임플란트 고정성 수복물로 구강회복 치료를 진행할 경우, 해당 악궁의 해부학적 상황과 대합치와의 관계를 고려하여 최종 보철물의 형태와 위치를 결정하는 과정과 이에 따라 다수의 임플란트를 계획된 방향과 각도로 식립하는 과정은 매우 중요하다. 본 증례는 기존 의치의 불편감으로 내원한 상악 무치악 환자를 computer-guided surgery를 통해 상부 보철물에 기반하여 이상적으로 계획된 위치에 임플란트를 식립하였다. 이를 통해 상악 전악 임플란트 고정성 보철물을 제작하여 구강 회복을 진행한 치료로 환자와 술자 모두 기능 및 심미적으로 만족할만한 결과를 얻었기에 이를 보고하고자 한다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.394-397
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• 2008

Recently WiBro network is installed for high speed wireless internet service by telecommunication service provider, however WiBro service is not provided in the region of mountain or difficult region to install network infra. Fixed repeater is used to resolve those shadow area problem in current WiBro network. This paper study introducing Ad-hoc based multi-hop relay instead of using fixed repeater in order to resolve those shadow area problem. Cost down of fixed repeater and active network expansion is possible to resolve shadow area problem by introducing multi-hop relay technology.

• 보건의료산업학회지
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• 제5권2호
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• pp.105-117
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• 2011

The purpose of this study is to investigate evaluation and improvement of long-term care hospitals for changing long-term care hospitals fee system. Data were collected from 104 CEOs in nationwide long-term care hospitals using structured self-administered questionnaires during August 17 to 31, 2009. Major results of the empirical analysis are as follows; first, to change fixed sum medical fee per day caused to decline the level of geriatric service in 87% of CEOs. Second, 79% of CEOs were dissatisfied with changing fixed sum medical fee per day, and 47% of them were dissatisfied with graded fee for doctor and nurse management. Finally, they suggested that to specialize and to differentiate of long-term care hospitals will drive to improve long-term care hospitals function and to measure workforce based on rate of filled vacancies will increase efficiency and productivity of doctor and nurse management.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.549-551
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• 2004

This paper used OPNET to simulate video streaming service a test IP network and MPLS network with the traffic shaping that have with CQ_ LLQ algorithm, LSP of fixed bandwidth, policy of limitation users and measures parameters such as delay, throughput, packet loss. To verify the performance of video streaming service in IP network and MPLS network, two scenario that have same topology and traffic source. One is the simulation for best-effort service in pure IP network. The other is the simulation for QoS-enabled service in MPLS Network. Based on simulation result, the MPLS network with CQ_ LLQ algorithm and fixed LSP show advantage of the video streaming service QoS, specially delay and packet loss

• 보건의료산업학회지
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• 제10권3호
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• pp.13-25
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• 2016

Objectives : The purposes of this study was to analyze business performance of university hospitals for the past 10 years. Methods : Management and finance data from 2005 to 2014 were collected from balance sheets, income statements and annual reports from 27 university hospitals. The dependant variable used was profitability which included return on assets, operating margin and net profit to gross revenues 1. The independent variables were general characteristics, liquidity, stability, activity and financial ratios. Results : University hospitals over the last 10 years had achieved good management performance. Using financial leverage, patient revenues, operating profit, nonpatient revenues, total assets and total debt, the total amount had increased by more than double. The ratio of fixed liability and fixed assets turnover was found to have a significant positive (+) effect on management performance in the years 2012-2014. Conclusions : Based on these results, this study suggests a more in-depth analysis using fixed liabilities and fixed assets.