• 한국정보통신학회논문지
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• 제15권2호
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• pp.292-298
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• 2011

생체신호 데이터의 의미와 그들 간의 연관관계를 정의하여 새로운 정보를 획득할 수 있는 형태의 모델링방법으로 온톨로지가 제시되고 있다. 온톨로지를 이용하여 생체신호 데이터를 지속적으로 관리함으로써 생체 신호 데이터의 체계적이고 논리적으로 표현이 가능하고, 이는 나아가 의료정보, 건강서비스 등 다양한 분야에서 질적으로 향상된 서비스를 제공하게 해주는 지식 자원으로 활용된다. 하지만 현재로는 생체 신호간의 연관 관계 중요성에 비해서 관련 연구가 활발하게 이루어지지 않고 있다. 따라서 생체 신호간의 연관관계를 찾아서 정의하고, 생체정보간의 의미표현이 필요하다. 그러기 위해서는 다양한 생체정보간의 연관 관계를 통해 체계적이고 구조화 된 정보를 만드는 것이 필요하다. 본 논문에서는 생체정보를 체계적이고 구조화 된 도메인 지식으로 활용하기 위한 모델로써 온톨로지를 이용하여 생체정보 온톨로지를 구축하고, 시나리오를 통해서 생체정보 온톨로지의 유용성을 검증하였다.

• 한국정보통신학회논문지
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• 제18권10호
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• pp.2403-2408
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• 2014

본 논문에서는 사용자들의 인접성(Proximity)과 밀집도(Density) 정보를 기반으로 D2D 광고 확산 목표 지역을 설정하고, 이 지역들을 대상으로 광고 전송을 수행함으로써 기존의 D2D 광고 확산 알고리즘에서 특정 지역으로 광고 전송이 편중되고 광고 범위 중첩되는 광고 효율 저하 문제를 해결하고자 한다. 본 논문에서 제안하는 광고 확산 알고리즘은 광고 확산을 위해 설정된 목표지역을 기반으로 광고 확산 경로를 점차적 설정하여 확장해 나감으로써 D2D 광고 확산 효율 향상에 기여한다. 또한, 제안 방안의 D2D 광고 확산 범위에 대해서 수학적으로 분석하고, 시뮬레이션을 통하여 다양한 사용자 밀집도 환경에 대한 기존 방안과 제안 방안의 성능 결과를 비교 분석한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.3159-3176
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• 2014

This work presents an analysis of the buffer features of an access router, especially the size, the impact on delay and the packet loss rate. In particular, we study how these features can affect the Quality of Service (QoS) of multimedia applications when generating traffic bursts in local networks. First, we show how in a typical SME (Small and Medium Enterprise) network in which several multimedia flows (VoIP, videoconferencing and video surveillance) share access, the upgrade of the bandwidth of the internal network may cause the appearance of a significant amount of packet loss caused by buffer overflow. Secondly, the study shows that the bursty nature of the traffic in some applications traffic (video surveillance) may impair their QoS and that of other services (VoIP and videoconferencing), especially when a certain number of bursts overlap. Various tests have been developed with the aim of characterizing the problems that may appear when network capacity is increased in these scenarios. In some cases, especially when applications generating bursty traffic are present, increasing the network speed may lead to a deterioration in the quality. It has been found that the cause of this quality degradation is buffer overflow, which depends on the bandwidth relationship between the access and the internal networks. Besides, it has been necessary to describe the packet loss distribution by means of a histogram since, although most of the communications present good QoS results, a few of them have worse outcomes. Finally, in order to complete the study we present the MOS results for VoIP calculated from the delay and packet loss rate.

• 한국멀티미디어학회논문지
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• 제7권5호
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• pp.721-736
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• 2004

휴대용 컴퓨터나 PDA등의 증가로 이동성에 대한 사용자의 요구가 점점 늘어나고 있으나 현재의 프로토콜은 자신의 IP 주소를 변경하지 않고 다른 네트워크로 이동할 경우 호스트의 새로운 위치로 IP 패킷을 전달할 수 없다. 이러한 문제를 해결하기 위해 IETF에서는 이동 IP라는 프로토콜을 제안하였다. 오늘날 인터넷은 최신형 서비스라 불리는 서비스를 제공하고 있다. 그러나 인터넷이 상업화됨에 따라 서비스 요구가 다양해지고 있으며 동시에 QoS에 대한 요구가 급증하고 있다. 정책기반 네트워크 관리는 IP 망을 대상으로 관리의 복잡성, QoS 및 보안에 있어서의 문제점을 해결할 수 있는 방안으로 제시하고 있다. 따라서 본 논문은 이동 IP 환경에서 인터넷 차별화 서비스를 제공하는 정책기반 네트워크 관리에 대한 네트워크 토폴로지 구성을 살펴보고 그들의 동작 절차와 구조를 제안하고, 정책 시나리오를 표현하기 위해 정책 클래스로 정책들을 나누어서 본 논문에서 제안하는 정책 언어를 사용하여 제시하였다. 또한 여러 가지 제어와 네트워크 동작 절차를 실행하기 위해 이동 IP 환경에서 인터넷 차별화 서비스를 제공하는 정책기반 네트워크 관리를 구현하였다.

• 한국융합학회논문지
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• 제10권11호
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• pp.463-470
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• 2019

의료용 대마의 소비 프로세스가 복잡해 환자 중심의 서비스 제공이 필요한 시점이다. 본 연구는 사용자 중심의 소비 프로세스 방향성 연구를 위해 의료용 대마의 소비 과정을 세 단계와 다섯 개의 절차로 정의하고 의료용 대마 구매 경험이 있는 사용자 인터뷰를 통해 소비 여정 지도를 작성하여 소비 과정에서 발생하는 페인 포인트를 발견하였다. 그 후 미국과 캐나다의 사례연구를 바탕으로 국내에 적용 가능한 시나리오를 시행범위에 따라 세 가지를 제시하였다. 의료용 대마 소비자의 경험에 기반한 사용자 중심의 연구라는 점에 의의가 있으며 향후 소비 프로세스 개선 시 참고 자료로 활용되길 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권7호
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• pp.3412-3432
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• 2019

Recent advances in radio frequency (RF) power transfer provide a promising technology to power sensor nodes. Adoption of mobile chargers to replenish the nodes' energy has recently attracted a lot of attention and the mobility assisted energy replenishment provides predictable and sustained power service. In this paper, we study the joint optimization of mobile charging and data gathering in sensor networks. A wireless multi-functional vehicle (WMV) is employed and periodically moves along specified trajectories, charge the sensors and gather the sensed data via one-hop communication. The objective of this paper is to maximize the uplink throughput by optimally allocating the time for the downlink wireless energy transfer by the WMV and the uplink transmissions of different sensors. We consider two scenarios where the WMV moves in a straight line and around a circle. By time discretization, the optimization problem is formulated as a 0-1 programming problem. We obtain the upper and lower bounds of the problem by converting the original 0-1 programming problem into a linear programming problem and then obtain the optimal solution by using branch and bound algorithm. We further prove that the network throughput is independent of the WMV's velocity under certain conditions. Performance of our proposed algorithm is evaluated through extensive simulations. The results validate the correctness of our proposed theorems and demonstrate that our algorithm outperforms two baseline algorithms in achieved throughput under different settings.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1845-1865
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• 2019

Current Internet is designed by lots of service providers with different objects and policies which make the direct deployment of radically new architecture and protocols on Internet nearly impossible without reaching a consensus among almost all of them. Network virtualization is proposed to fend off this ossification of Internet architecture and add diversity to the future Internet. As an important part of network virtualization, virtual network embedding (VNE) problem has received more and more attention. In order to solve the problems of large embedding cost, low acceptance ratio (AR) and environmental adaptability in VNE algorithms, cognitive method is introduced to improve the adaptability to the changing environment and a cognitive virtual network embedding algorithm based on weighted relative entropy (WRE-CVNE) is proposed in this paper. At first, the weighted relative entropy (WRE) method is proposed to select the suitable substrate nodes and paths in VNE. In WRE method, the ranking indicators and their weighting coefficients are selected to calculate the node importance and path importance. It is the basic of the WRE-CVNE. In virtual node embedding stage, the WRE method and breadth first search (BFS) algorithm are both used, and the node proximity is introduced into substrate node ranking to achieve the joint topology awareness. Finally, in virtual link embedding stage, the CPU resource balance degree, bandwidth resource balance degree and path hop counts are taken into account. The path importance is calculated based on the WRE method and the suitable substrate path is selected to reduce the resource fragmentation. Simulation results show that the proposed algorithm can significantly improve AR and the long-term average revenue to cost ratio (LTAR/CR) by adjusting the weighting coefficients in VNE stage according to the network environment. We also analyze the impact of weighting coefficient on the performance of the WRE-CVNE. In addition, the adaptability of the WRE-CVNE is researched in three different scenarios and the effectiveness and efficiency of the WRE-CVNE are demonstrated.

• 대한통합의학회지
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• 제6권4호
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• pp.149-169
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• 2018

Purpose : This study was to develop a strategy for modeling future workforce projections to serve as a basis for analyzing annual supply of and demand for physical therapists across the South Korea into 2030. Methods : In-and-out movement model was used to project the supply of physical therapists. The demand was projected according to the demand-based method which consists of four-stages such as estimation of the utilization rate of the base year, forecasting of health care utilization of the target years, forecasting of the requirements of clinical physical therapists and non-clinical physical therapists based on the projected physical therapists. Results : Based on the current productivity standards, there will be oversupply of 39,007 to 40,875 physical therapists under the demand scenario of average rate in 2030, undersupply of 44,663 to 49,885 under the demand scenario of logistic model, oversupply of 16,378 to 19,100 under the demand scenario of logarithm, and oversupply of 18,185 to 20,839 under the demand scenario of auto-regressive moving average (ARIMA) model in 2030. Conclusion : The result of this projection suggests that the direction and degree of supply of and demand for physical therapists varied depending on physical therapists productivity and utilization growth scenarios. However, the need for introduction of a professional physical therapist system and the need to provide long-term care rehabilitation services are actively being discussed in entering the aging society. If community rehabilitation programs for rehabilitation of disabled people and the elderly are activated, the demand of physical therapists will increase, especially for elderly people. Therefore, healthcare policy should focus on establishing rehabilitation service infrastructure suitable for an aging society, providing high-quality physical therapy services, and effective utilization of physical therapists.

• 보건행정학회지
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• 제28권4호
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• pp.378-391
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• 2018

Background: People who were born in different years, that is, different birth cohorts, grow in varying socio-historical and dynamic contexts, which result in differences in social dispositions and physical abilities. Methods: This study used age-period-cohort analysis method to establish explanatory models on healthcare expenditure in Korea reflecting birth cohort factor using intrinsic estimator. Based on these models, we tried to investigate the effects of ageing population on future healthcare expenditure through simulation by scenarios. Results: Coefficient of cohort effect was not as high as that of age effect, but greater than that of period effect. The cohort effect can be interpreted to show 'healthy ageing' phenomenon. Healthy ageing effect shows annual average decrease of -1.74% to 1.57% in healthcare expenditure. Controlling age, period, and birth cohort effects, pure demographic effect of population ageing due to increase in life expectancy shows annual average increase of 1.61%-1.80% in healthcare expenditure. Conclusion: First, since the influence of population factor itself on healthcare expenditure increase is not as big as expected. Second, 'healthy ageing effect' suggests that there is a need of paradigm shift to prevention centered-healthcare services. Third, forecasting of health expenditure needs to reflect social change factors by considering birth cohort effect.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.5723-5743
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• 2018

The evolving internet-based services demand high-speed data transmission in conjunction with scalability. The next generation optical network has to exploit artificial intelligence and cognitive techniques to cope with the emerging requirements. This work proposes a novel way to solve the dynamic provisioning problem in optical network. The provisioning in optical network involves the computation of routes and the reservation of wavelenghs (Routing and Wavelength assignment-RWA). This is an extensively studied multi-objective optimization problem and its complexity is known to be NP-Complete. As the exact algorithms incurs more running time, the heuristic based approaches have been widely preferred to solve this problem. Recently the software-defined networking has impacted the way the optical pipes are configured and monitored. This work proposes the dynamic selection of path computation algorithms in response to the changing service requirements and network scenarios. A software-defined controller mechanism with a novel packet matching feature was proposed to dynamically match the traffic demands with the appropriate algorithm. A software-defined controller with Path Computation Element-PCE was created in the ONOS tool. A simulation study was performed with the case study of dynamic path establishment in ONOS-Open Network Operating System based software defined controller environment. A java based NOX controller was configured with a parent path computation element. The child path computation elements were configured with different path computation algorithms under the control of the parent path computation element. The use case of dynamic bulk path creation was considered. The algorithm selection method is compared with the existing single algorithm based method and the results are analyzed.