• 한국IT서비스학회:학술대회논문집
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• 한국IT서비스학회 2009년도 춘계학술대회
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• pp.87-90
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• 2009

A u-city is a vision of a city with computers and sensors built in to its infrastructure, and data sharing among the various information systems. A u-City provides several u-City services to the u-City clients. The u-City services for local governments contain two types of functions: common function and specified function. It is needed a study on generation of specified service models of local governments. The proposed service model divides functions of the city into two service areas: common support service and specified support service. And we suggest the way to generate the u-services of each local government in this paper.

• 한국경영과학회지
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• 제26권2호
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• pp.111-130
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• 2001

This study aims to examine the difference between market orientation, organizational service orientation, performances (employee satisfactions and business performances) across the type of hotel grade, and investigate the effect on performances of market orientation, organizational service orientation, and interaction of these two factors. For these purposes the authors developed 13 research proposals. The data for this research which were collected from Korean hotel firms’ managers and employees were analyzed with one-way ANOVA, regression analysis. The findings can be summarized as follows. First, five-star hotels display higher levels of market orientation, organizational service orientation, performance (employee satisfaction, business performance) than four-star and three-star hotels. Second, market orientation, organizational service orientation, and interaction of these two variables have significant effects on performances(employee satisfaction, business performance).

• 정보교육학회논문지
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• 제23권4호
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• pp.343-353
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• 2019

본 연구의 목적은 수감각이 요구되는 문제 해결과정에서 초등예비교사들이 선호하는 전략을 분석한 후, 컴퓨팅 사고력에 기반하여 수감각 능력을 향상시키는 방안을 연구함에 있다. 두 가지 다른 수감각 요소로 구성된 검사지를 이용하여 57명의 초등예비교사들이 선호하는 전략을 분석한 결과, 그들은 수감각 기반 전략보다 규칙기반 전략을 더 선호하였으며, 이러한 결과는 선행연구[13][14][20]과 일치하였다. 이러한 상황을 개선하기 위해, 분석된 결과와 CSTA와 ISTE(2011)의 9가지 컴퓨팅 사고력 요소를 활용하여 수감각 능력을 향상시킬 수 있는 방법을 제시한다.

• Journal of Information Processing Systems
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• 제14권2호
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• pp.377-395
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• 2018

Aiming at the problem of service reliability in resource reservation in cloud computing environments, a model of dynamic cloud resource reservation based on trust is proposed. A domain-specific cloud management architecture is designed in which resources are divided into different management domains according to the types of service for easier management. A dynamic resource reservation mechanism (DRRM) is used to test users' reservation requests and reserve resources for users. According to user preference, several resources are chosen to be candidate resources by fuzzy cluster analysis. The fuzzy evaluation method and a two-way trust evaluation mechanism are adopted to improve the availability and credibility of the model. An analysis and simulation experiments show that this model can increase the flexibility of resource reservation and improve user satisfaction.

• 동아시아식생활학회지
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• 제20권6호
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• pp.987-996
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• 2010

The purpose of this study was to measure customers' perception of the service quality of Korean restaurants and then compare differences in perceived service quality according to customer nationality. Self-administered questionnaires were completed by 2812 subjects, and data were analyzed by frequency, chi-square, t-test, one-way ANOVA, factor, reliability, cluster, and discriminant analysis. Results of the study were as follows. The factor analysis of perceived service quality produced four factors, employee service (5 variables), menu quality (4 variables), price & value (4 variables), and physical environment (4 variables). Cronbach's alpha values for reliability were over 0.8 for all factors. Further, a significant difference was observed in service quality, which was perceived according to customer nationality. A higher mean value of perceived service quality was held by foreigners when compared to Koreans. Especially, the mean value of perceived service quality was significantly low for all items for Japanese compared to foreigners. Cluster analysis divided subjects into two groups based on attitude toward service quality of Korean restaurants: an unfavorable group and favorable group. These two groups differed from each other in general characteristics as well. Limitations and future research directions are also discussed.

• 산업경영시스템학회지
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• 제39권2호
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• pp.28-36
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• 2016

Recently, owing to the development of ICT industry and wide spread of smart phone, the number of people who use car sharing service are increased rapidly. Currently two-way car sharing system with same rental and return locations are mainly operated since this system can be easily implemented and maintained. Currently the demand of one-way car sharing service has increase explosively. But this system have several obstacle in operation, especially, vehicle stock imbalance issues which invoke vehicle relocation. Hence in this study, we present an optimization approach to depot location and relocation policy in one-way car sharing systems. At first, we modelled as mixed-integer programming models whose objective is to maximize the profits of a car sharing organization considering all the revenues and costs involved and several constraints of relocation policy. And to solve this problem efficiently, we proposed a new method based on particle swarm optimization, which is one of powerful meta-heuristic method. The practical usefulness of the approach is illustrated with a case study involving satellite cities in Seoul Metrolitan Area including several candidate area where this kind systems have not been installed yet and already operating area. Our proposed approach produced plausible solutions with rapid computational time and a little deviation from optimal solution obtained by CPLEX Optimizer. Also we can find that particle swarm optimization method can be used as efficient method with various constraints. Hence based on this results, we can grasp a clear insight into the impact of depot location and relocation policy schemes on the profitability of such systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1418-1432
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• 2013

This paper studies the problem of secure information exchange between two sources via multiple relays in the presence of an eavesdropper. To this end, we propose a relay beamforming scheme, i.e., relay beamforming with artificial noise (RBwA), where the relay beamforming vector and the artificial noise vector are jointly designed to maintain the received signal-to-interference-ratio (SINR) at the two sources over a predefined Quality of Service (QoS) threshold while limiting the received SINR at the eavesdropper under a predefined secure threshold. For comparison, the relay beamforming without artificial noise (RBoA) is also considered. We formulate two optimization problems for the two schemes, where our goal is to seek the optimal beamforming vector to minimize the total power consumed by relay nodes such that the secrecy of the information exchange between the two sources can be protected. Since both optimization problems are nonconvex, we solve them by semidefinite program (SDP) relaxation theory. Simulation results show that, via beamforming design, physical layer secrecy of two-way relay networks can be greatly improved and our proposed RBwA outperforms the RBoA in terms of both low power consumption and low infeasibility rate.

• 한국IT서비스학회지
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• 제11권2호
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• pp.93-106
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• 2012

Recently, a Game Shut-down policy, partially limiting the time for the use of online game service, has been implemented in order to protect the youth from the excessive use of games by limiting their access to games in the late hours, based on the serious side effects of online games on the youth. However, the effectiveness of a Game Shut-down policy becomes a social issue. Thus, this study aims to investigate the alternative policies through the levels of the communications suggested by the theory of excellence, for the successful implementation of the policy. As a result of the study, the government and students, the recipient of those policies, need to strengthen their two-way communication in respect of the Game Shut-down policy, breaking from the existing views on the perception. The problem is that the current government's way of the communication for the Game Shut-down policy is one-way and it is aiming at achieving the objectives only. Thus, the communication in this manner will cause the side effect. 'the opportunistic violation of the system in the future', even if the students seemingly accept the system. Two-way communication will enhance the motivation for the voluntary acceptance of the system and lower the motivation for the opportunistic violation of the system. Thus, the government needs to strengthen two-way communication in the future.

• 한국통신학회논문지
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• 제31권11B호
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• pp.969-978
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• 2006

멀티미디어 서비스의 증가는 인터넷 콘텐츠의 새로운 국면으로 나타나고 있다. IP텔레폰, 화상채팅과 같은 멀티미디어 서비스는 대역폭, 지터, 패킷유실, 전송지연 듯의 네트워크 파라미터에 민감한 데이터이다. 멀티미디어 서비스의 QoS 보장을 위해서 RTP/RTCP를 이용하여 네트워크 상황을 판단하고 전송률을 조절하는 기법이 연구되고 있다. 본 논문에서는 최선형(Best-Effort) 서비스를 제공하는 현 인터넷 구조에서 RTP/RTCP 구조를 확장하여 단방향 전송 지연시간을 구하고 이를 이용하여 네트워크 상황을 판단하는 기법을 제안한다. 또한 단방향 전송지연을 이용하여 급변하는 네트워크 상황에 즉각적으로 대처하기 위한 동적인 RTCP 구조를 제안한다. 모의 실험결과 제안한 단방향 전송 지연 기법은 GPS를 이용한 단방향 전송 기법과 유사한 성능을 보였으며, 제안한 동적 RTCP 기법은 적은 RTCP RR패킷 전송으로 패킷 손실률이 감소하는 효과를 얻었다.

• 설비공학논문집
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• 제26권5호
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• pp.218-223
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• 2014

Korea District heating corp. recently give an attention to combine the district heating and supply pipes as a two pipe system that are in the present system separated with room heating and warm water supply pipe, and the two pipe system is commonly applied for heating service in European countries. In the new two pipe system, only one heat source is supplied to a house and partitioned into room heating and warm water supply by household substation. So the effective distribution of supplied heat source in accordance to user intention is very important. This paper presents the development and performance test of three-way proportional control valve for a combined heat source system in district heating. The proposed valve is controlled to partition heat source into two different directions : hot water distributor for space heating and household substation for warm water supply in response to the pressure drops of tap water caused by the user. The performance investigation is shown within 3% of error compared to the theoretical model of the three-way proportional valve and its controllability is verified.