• 한국콘텐츠학회논문지
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• 제10권1호
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• pp.407-416
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• 2010

최근 유비쿼터스 기술이 발달하고 일상생활에 접목되면서, 관광 정보 서비스에 유비쿼터스 기술 도입이 추진되고 있다. 그러나 유비쿼터스 기술을 적용하고 관광 콘텐츠를 개발하는데 있어 각 지자체는 선례나 기준이 없어 개별적이고 독자적으로 구축, 서비스하고 있는 실정이다. 본 연구는 향후 가속화될 유비쿼터스 관광정보 서비스의 표준적이고 효과적인 구축 방안을 수립하기 위한 기초단계로서 현재 국내에서 구축, 서비스되고 있는 유비쿼터스 관광정보서비스의 사례를 수집, 분석하고자 하였다. 먼저, 문헌 조사를 통하여 관광정보서비스에 활용 가능한 다양한 유비쿼터스 기술 동향에 대해 살펴보고, 유비쿼터스 관광정보서비스의 대표적인 사례들을 수집하여 유비쿼터스 적용기술, 디바이스 활용, 서비스 콘텐츠의 내용과 형식 등 네 가지 측면에서 현황과 문제점을 분석하였다. 분석 결과를 종합하여 향후 유비쿼터스 관광정보 서비스의 개괄적인 구축에 대한 시사점을 네 가지 각 항목에 따라 토의하였다. 본 연구는 각 지자체가 개별적이고 독자적으로 구축하고 있는 유비쿼터스 관광 콘텐츠의 총괄적인 현황과 문제점을 파악할 수 있게 하며, 전국적인 표준안을 마련하여 통합, 구축 및 운영에 대한 필요성을 역설하고 구축을 위한 개괄적인 방향을 시사한다는데 의의가 있다고 하겠다.

• 한국의료질향상학회지
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• 제26권2호
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• pp.66-76
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• 2020

Purpose:Hospitals provide top medical service using exceptional manpower, medical technology, and state-of-the-art equipment, thus raising the standard of customer satisfaction. In addition, their medical service is becoming higher than before. One-stop service is a good way to improve the quality of customer-centered service as a qualitative marketing strategy. This study thus aims to facilitate subsequent research and compare customer satisfaction before and after one-stop service. Methods: The study included 72 patients who received the reserved examination and one-stop service for 20 days from April 23 to May 12, 2014. The surveyed questionnaire data were analyzed using SPSS 18.00. Results: The comparison results of customer satisfaction showed that the satisfaction score was generally high in the areas of kindness of examination staff, the speedy/accuracy of work processing of examination staff, and the kindness of reservation staff. The group before one-stop service showed their dissatisfaction with repeated visits and difficulty of booking a desired day. The group after one-stop service showed dissatisfaction with the long waiting time for examination or same-day treatment. Conclusion: The one-stop service showed good results, but new uncomfortable issues for the customer were revealed as well, which may result in more work of employees. Considering the characteristics of various clinical departments, the author hopes to find an efficient operation plan through the development and improvement of an appropriate one-stop service method.

• 서비스연구
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• 제11권2호
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• pp.67-77
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• 2021

본 연구는 기존의 장례의식 중심의 상조기업 비즈니스가 조문객과 상주 중심의 서비스로 변모하기 위해 반드시 필요한 고객경험 중심 혁신전략 방법론에 관한 연구이다. 이를 위해서 서비스사이언스 관점에서 장례산업의 환경변화와 그 안에서의 고객경험 의의 및 가치, 고객경험관리 차원의 긍정적 고객경험, 부정적 고객경험 등의 문헌 연구를 수행하였고, 상조회사의 고객경험 혁신을 위한 구체적인 모델을 제시하고 입증하기 위한 연구를 수행하였다. 장례산업의 고객경험 혁신 전략의 의미는 현재 상태에서 목표 상태에 도달할 수 있는 여러 대안을 고객을 중심으로 탐색하고 그 중 최적의 전환 계획을 선택하는 것이다. 적용효과는 고객의 선호적인 감정을 유발시켜 차별화를 만들어내는 핵심이 되며, 고객경험 데이터가 상조회사의 경제적 관점의 자원 투입에 중요한 의사결정에 높은 도움이 된다는 것이다. 이와 같은 상조회사 혁신모델을 제시하였다. 고객중심의 상조서비스를 분석하여 그 가치를 연구하였다. 마지막으로 고객경험에 대한 측정 절차, 진단/평가, 혁신전략, 상조기업의 성과를 변수로 활용하여 단순회귀분석 기반으로 인과관계를 분석하였고, 결과적으로 관계가 유의미하다는 것이 설명되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권10호
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• pp.4680-4697
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• 2017

In future, since the user experience plays a more and more important role in the development of today's communication systems, quality of experience (QoE) becomes a widely used metric, which reflects the subjective experience of end users for wireless service. In addition, the energy efficiency is an increasingly important problem with the explosive growth in the amount of wireless terminals and nodes. Hence, a QoE-aware energy efficiency maximization based joint user access selection and power allocation approach is proposed to solve the problem. We transform the joint allocation process to an optimization of energy efficiency by establishing an energy efficiency model, and then the optimization problem is solved by chaotic clone immune algorithm (CCIA). Numerical simulation results indicate that the proposed algorithm can efficiently and reliably improve the QoE and ensure high energy efficiency of networks.

• Journal of Communications and Networks
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• 제7권4호
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• pp.509-524
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• 2005

Due to the strict requirements of emerging applications, per-flow admission control is gaining increasing importance. One way to implement per-flow admission control is using an on­path resource reservation protocol, where the admission decision is made hop-by-hop after a new flow request arrives at the network boundary. The next-steps in signaling (NSIS) working group of the Internet engineering task force (IETF) is standardising such an on-path signaling protocol. One of the reservation methods considered by NSIS is reduced-state mode, which, suiting the differentiated service (DiffServ) concept, only allows per-class states in interior nodes of a domain. Although there are clear benefits of not dealing with per-flow states in interior nodes-like scalability and low complexity-, without per-flow states the handling of re-routed flows, e.g., after a failure, is a demanding and highly non-trivial task. To be applied in carrier-grade networks, the protocol needs to be resilient in this situation. In this article, we will explain the consequences of a route failover to resource reservation protocols: Severe congestion and incorrect admission decisions due to outdated reservation states. We will set requirements that handling solutions need to fulfill, and we propose extensions to reduced-state protocols accordingly. We show with a set of simulated scenarios that with the given solutions reduced-state protocols can handle re-routed flows practically as fast and robust as stateful protocols.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권9호
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• pp.4242-4263
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• 2017

Multi-User Multiple-Input Multiple-Output (MU-MIMO) technology has recently attracted significant attention from academia and industry because of it is increasingly important role in improving networks' capacity and data rate. Moreover, MU-MIMO systems for the Fifth Generation (5G) have already been researched. High Quality of Service (QoS) and efficient operations at the Medium Access Control (MAC) layer have become key requirements. In this paper, we propose a downlink MU-MIMO MAC protocol based on adaptive Channel State Information (CSI) feedback (called MMM-A) for Wireless Local Area Networks (WLANs). A modified CSMA/CA mechanism using new frame formats is adopted in the proposed protocol. Specifically, the CSI is exchanged between stations (STAs) in an adaptive way, and a packet selection strategy which can guarantee a fairer QoS for scenarios with differentiated traffic is also included in the MMM-A protocol. We then derive the expressions of the throughput and access delay, and analyze the performance of the protocol. It is easy to find that the MMM-A protocol outperforms the commonly used protocols in terms of the saturated throughput and access delay through simulation and analysis results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.2061-2080
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• 2013

Roaming authentication protocol is widely used in wireless network which can enable a seamless service for the mobile users. However, the classical approach requires the home server's participation during the authentication between the mobile user and the foreign server. So the more the roaming requests are performed the heavier burden will be on the home server. In this paper, we propose a new roaming authentication framework for wireless communication without the home server's participation. The new roaming authentication protocol in the new framework takes advantage of the ID-based cryptography and provides user anonymity. It has good performance compared with the roaming authentication protocols whose authentication do not need the home server's participation in terms of security and computation costs. Moreover, a new User-to-User authentication protocol in the new framework is also present. All the authentications proposed in this paper can be regarded as a common construction and can be applied to various kinds of wireless networks such as Cellular Networks, Wireless Mesh Networks and Vehicle Networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.3921-3944
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• 2015

Currently Energy-Saving (ES) methods in cellular networks could be improved, as compensation method for irregular Base Station (BS) deployment is not effective, most regional ES algorithm is complex, and performance decline caused by ES action is not evaluated well. To resolve above issues, a low-complexity energy efficient BS cooperation mechanism for Long Time Evolution (LTE) networks is proposed. The mechanism firstly models the ES optimization problem with coverage, resource, power and Quality of Service (QoS) constraints. To resolve the problem with low complexity, it is decomposed into two sub-problems: BS Mode Determination (BMD) problem and User Association Optimization (UAO) problem. To resolve BMD, regional dynamic multi-stage algorithms with BS cooperation pair taking account of load and geographic topology is analyzed. And then a distributed heuristic algorithm guaranteeing user QoS is adopted to resolve UAO. The mechanism is simulated under four LTE scenarios. Comparing to other algorithms, results show that the mechanism can obtain better energy efficiency with acceptable coverage, throughput, and QoS performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권5호
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• pp.2177-2193
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• 2018

This paper studies resource allocation schemes for the relay-aided cooperative system consisting of multiple source-destination pairs and decode-forward (DF) relays. Specially, relaying selection, multisubcarrier pairing and assignment, and power allocation are investigated jointly. We consider a combinatorial optimization problem on quality of experience (QoE) and energy consumption based on relay-aided cooperative system. For providing better QoE and lower energy consumption we formulate a multi-objective optimization problem to maximize the total mean opinion score (MOS) value and minimize the total power consumption. To this end, we employ the nondominated sorting genetic algorithm version II (NSGA-II) and obtain sets of Pareto optimal solutions. Specially, two formulas are devised for the optimal solutions of the multi-objective optimization problems with and without a service priority constraint. Moreover, simulation results show that the proposed schemes are superior to the existing ones.

• 전력전자학회논문지
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• 제24권3호
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• pp.139-146
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• 2019

As the number of electric vehicles (EVs) in Jejudo Island increases, the secondary use of EV batteries is becoming increasingly mandatory not only in reducing greenhouse gas emissions but also in promoting resource conservation. For the secondary use of EV batteries, their capacity and performance at the end of automotive service should be evaluated properly. In this study, the battery state information from the on-board diagnostics or OBD2 port was acquired in real time while driving three distinct routes in Jejudo Island, and then the battery operating characteristics were assessed with the driving routes. The route with higher altitude led to higher current output, i.e., higher C-rate, which would reportedly deteriorate state of health (SOH) faster. In addition, the SOH obtained from the battery management system (BMS) of a 2017 Kia Soul EV with a mileage of 55,000 km was 100.2%, which was unexpectedly high. This finding was confirmed by the SOH estimation based on the ratio of the current integral to the change in state of charge. The SOH larger than 100% can be attributed to the rated capacity that was lower than the nominal capacity in EV application. Therefore, considering the driving environment and understanding the SOH estimation process will be beneficial and necessary in evaluating the capacity and performance of retired batteries for post-vehicle applications.