• International Journal of Computer Science & Network Security
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• 제23권7호
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• pp.219-230
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• 2023

Wireless Body Area Networks (WBANs) have made it easier for healthcare workers and patients to monitor patients' status continuously in real time. WBANs have complex and diverse network structures; thus, management and control can be challenging. Therefore, considering emerging Software-defined networks (SDN) with WBANs is a promising technology since SDN implements a new network management and design approach. The SDN concept is used in this study to create more adaptable and dynamic network architectures for WBANs. The study focuses on comparing the performance of two SDN controllers, POX and Ryu, using Mininet, an open-source simulation tool, to construct network topologies. The performance of the controllers is evaluated based on bandwidth, throughput, and round-trip time metrics for networks using an OpenFlow switch with sixteen nodes and a controller for each topology. The study finds that the choice of network controller can significantly impact network performance and suggests that monitoring network performance indicators is crucial for optimizing network performance. The project provides valuable insights into the performance of SDN-based WBANs using POX and Ryu controllers and highlights the importance of selecting the appropriate network controller for a given network architecture.

• Journal of information and communication convergence engineering
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• 제8권3호
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• pp.251-257
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• 2010

The realization of u-City is coming near in some local governments by applying various city services, namely, u-City services to the city construction field to improve competitiveness of the city. But it is a reality that some local governments are experiencing many trial and errors in application of the u-City service in addition to the problem posing that the u-City service is not considering characteristics of development or application environment of an individual city. The present research proposes a service model for on-site application of the u-City service to solve this problem. The proposed model suggests a method for specifically conceptualizing and objectifying the on-site application that the existing concept-oriented model or an architecture-oriented model, etc. didn't provide. The verification system on effectiveness or effects of the u-City service model to remove ambiguity on the u-City service especially. The verification system of the u-City service model grasps the technology, function, procedure and target, etc. that the u-City service contains, evaluates whether the model satisfies conditions that the model should have, and secures objectivity and predictability of the u-City service model through confirmation on propriety, implementation and effectiveness, etc.

• 산업경영시스템학회지
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• 제14권24호
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• pp.149-154
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• 1991

The one of the important problems in the design of queueing systems is the decision of the order of service stations. The object of this problem is the decision of the order that minimizes the expected sojourn time per customer in the given arrival process and service time distributions. In this paper, the tandem queueing system in series is studied with the emphasis on the optimal order of the tandem queueing system which has three stations with single servers. In one system, customers arrive at the first station with Poisson process. This system is composed of service stations with a constant, a general distribution and a Exponential distribution is studied. To select the optimal order after the orders of each pair of two stations is decided, it is compared the two orders of system. With this results, total expected delay of the systems which has three stations is compared. The result is the best that service station with constant time is on the first place, then the service station with general distribution and the service station with Exponential distribution is followed. And the other system is consist of service stations with a constant and two probabilistic distributions. In this case, two probabilistic distributions has a non-overlapping feature. It is the optimal order that the service station with constant time is on the first place then the service station with longer service time and the service station with shorter service time is followed.

• 한국정보통신학회논문지
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• 제8권2호
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• pp.344-351
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• 2004

정보통신 기술의 발전으로 응용 서비스는 멀티미디어화 되어 가며, 짧은 라이프 싸이클을 보이고 있다. 통신망 사업자와 서비스 제공자는 신속한 서비스 제공과 통신망의 효율적인 유지보수를 위해 TMN (Telecommunication Management Network)과 개방형 정보통신망 (Open Networking Architecture, TINA)을 도입하고 있다. 본 논문에서는 이러한 추세에 따라 TINA-C에서 제안하는 소프트웨어 인프라 구조에서 개발된 개별 서비스를 통합하여 신규 서비스를 생성하는 기능 구조를 모델링하고 이를 구현하였다. TINA 규격에 따른 화상회의와 VOD 서비스를 대상으로 신규 비디오 프리젠테이션 서비스를 컴포지션 하였으며, 컴포지션 객체(CompPA, asCompUAP, CompUSM, SC)를 설계하였다.

• Journal of Information Processing Systems
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• 제15권2호
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• pp.440-448
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• 2019

The Internet of Things (IoT) is one of the main enablers for situation awareness needed in accomplishing smart cities. IoT devices, especially for monitoring purposes, have stringent timing requirements which may not be met by cloud computing. This deficiency of cloud computing can be overcome by fog computing for which fog nodes are placed close to IoT devices. Because of low capabilities of fog nodes compared to cloud data centers, fog nodes may not be deployed with all the services required by IoT devices. Thus, in this article, we focus on the issue of fog service placement and present the recent research trends in this issue. Most of the literature on fog service placement deals with determining an appropriate fog node satisfying the various requirements like delay from the perspective of one or more service requests. In this article, we aim to effectively place fog services in accordance with the pre-obtained service demands, which may have been collected during the prior time interval, instead of on-demand service placement for one or more service requests. The concept of the logical fog network is newly presented for the sake of the scalability of fog service placement in a large-scale smart city. The logical fog network is formed in a tree topology rooted at the cloud data center. Based on the logical fog network, a service placement approach is proposed so that services can be placed on fog nodes in a resource-effective way.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.175-176
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• 2018

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.887-890
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• 2007

현재 많은 대학에서는 대학경쟁력 강화 차원에서 유비쿼터스 캠퍼스에 대한 연구를 활발히 진행하고 있으며, 일부 대학에서는 통신회사와 함께 구축하여 학내 서비스로 활용하고 있다. 그러나 현재의 유비쿼터스 캠퍼스 환경은 학생들이 해당 서비스를 실질적으로 사용하기에는 관련기기의 보급이 미흡하여 실용성이 떨어지고, 대학과 업체 중심의 개발로 인해 진정한 학생 중심의 서비스를 지원하지 못한다는 한계점을 갖고 있다. 이에 본 논문에서는 사용자 IT 인프라 분석을 통한 실효성 있는 서비스의 구현을 통해서 보다 학생 중심적이고 학생의 유비쿼터스 활용을 분석할 수 있는 모델에 관해 연구하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권12호
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• pp.4364-4384
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• 2021

The dynamic network state and the mobility of the terminals make the service function chain (SFC) orchestration mechanisms based on static and deterministic assumptions hard to be applied in SDN/NFV mobile edge computing networks. Designing dynamic and online SFC orchestration mechanism can greatly improve the execution efficiency of compute-intensive and resource-hungry applications in mobile edge computing networks. In order to increase the overall profit of service provider and reduce the resource cost, the system running time is divided into a sequence of time slots and a dynamic orchestration scheme based on an improved column generation algorithm is proposed in each slot. Firstly, the SFC dynamic orchestration problem is formulated as an integer linear programming (ILP) model based on layered graph. Then, in order to reduce the computation costs, a column generation model is used to simplify the ILP model. Finally, a two-stage heuristic algorithm based on greedy strategy is proposed. Four metrics are defined and the performance of the proposed algorithm is evaluated based on simulation. The results show that our proposal significantly provides more than 30% reduction of run time and about 12% improvement in service deployment success ratio compared to the Viterbi algorithm based mechanism.

• 인터넷정보학회논문지
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• 제21권1호
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• pp.103-110
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• 2020

The EDISON is a platform that supports numerical analysis for problem solving in computational science and engineering. We provide a cloud service for users, and provide an environment to access and execution of the simulation service on the web. For now, the EDISON platform provides simulation services for eight applied field on computational science engineering. Users can check the numerical analysis result by web in the computational science and engineering platform. In addition, various services such as community activity with other researchers, and the configuration of simulation environment by user 's needs can be provided. A representative service of the EDISON platform is a web-based simulation service that performs numerical analysis for problem solving of various computational science and engineering. Currently, EDISON platform provides workbench simulation service. It is the web-based simulation execution environment, and result analysis to provide simulation regardless of various personal computing resource or environment in each numerical analysis. In this paper, we build an interface for pre and post processor that can be used in conjunction with the workbench-based simulation service provided by EDISON platform. We provide a development environment with interface that is implemented by applying a pre and post processor optimized for the simulation service. According to simulation and execution are performed by linking the new workbench-based simulation service to the pre and post processor.

• International Journal of Quality Innovation
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• 제9권1호
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• pp.113-133
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• 2008

In recent years, speedy development of Taiwan's hotel industry intensifies market competition, customers' demands on hotel services quality also increase with the increase of their consumption consciousness, and their demands on hotel types diversify, therefore hotel industry should concern on their unique management services quality brought by their different hotel types. The current designed service system or service transmission process may fail to meet customers' demands owing to emphasizing degree gap in service quality. What is worse, it is difficult for hotel industry to actualize complete customer segregation and to provide customized services, therefore comprehensive understanding of customers' demands on the service quality of different types hotels would contribute to operating management improvement of Taiwan hotel industry. This paper divides Taiwan hotels into three types: international tourism commercial type, holiday type and motel, the general hotels. It studies the emphasize degree gap in service quality between the industry and the customers. Data analysis shows that service quality gap (perceived gap) of hotels of different types exists in several quality aspects; what's more, the perceived gaps, service quality aspects, and its items of different types of hotel are also different. After an integrated analysis, this paper puts forward a general and customer-oriented quality item suitable for hotel industry to shorten the perceived gap of service quality, so that the hotel industry could design a service system and service transfer system, which could meet most lodging customers' demands in the context of pluralized customer sources.