• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.204-209
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• 2003

In an urban area telecommunication using wireless system, the accurate prediction and analysis of wave propagation characteristics are very important to determine the service area, optimized selection of base station, and cell design, etc. In the stage of these analyses, we have to present the propagation prediction model which is varied with the type of antenna, directional angle, and configuration of the ground in our urban area. In addition we need to perform an analysis of the conventional model which is similar to ours and dig out the parameters to evaluate the wave environment before the cell design for the selected area. In this paper, we propose a wave propagation prediction model concerning the topography and obstacles in our urban area. We extract the parameters and apply them to the proposed wave environment for the simulation analyzing the propagation characteristics. Throughout these analyzing procedure, we extracted the essential parameters such as the position of the base station, the height of topography, and adequate type and height of the antenna with our preferable correctness.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.3
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• pp.296-304
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• 2015

Vessel Traffic Service (VTS) is the service that provides ships navigating on a sea transportation route with guidance and advice about geographical environment and other attentive information for their safety. In this study we point out that currently, constructing additional VTSs is required to prevent ships from unexpected accident on their navigation. We first select several candidate locations for constructing VTSs, based on the amount of marine transportation and its potential development possibility. Then, we present an optimization model in which the maximum area coverage is achieved by determining new locations of VTS subject to budget limitation. The problem can be modeled as a binary integer program and it provides an optimal solution for new VTS locations to be constructed under the consideration of the currently located VTSs in Korea.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5344-5356
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• 2018

Nowadays with the help of Location-Based Social Networks (LBSNs), users of Point-of-Interest (POI) recommendation service in LBSNs are able to publish their geo-tagged information and physical locations in the form of sign-ups and share their experiences with friends on POI, which can help users to explore new areas and discover new points-of-interest, and promote advertisers to push mobile ads to target users. POI recommendation service in LBSNs is attracting more and more attention from all over the world. Due to the sparsity of users' activity history data set and the aggregation characteristics of sign-in area, conventional recommendation algorithms usually suffer from low accuracy. To address this problem, this paper proposes a new recommendation algorithm based on a novel Preference-Content-Region Model (PCRM). In this new algorithm, three kinds of information, that is, user's preferences, content of the Point-of-Interest and region of the user's activity are considered, helping users obtain ideal recommendation service everywhere. We demonstrate that our algorithm is more effective than existing algorithms through extensive experiments based on an open Eventbrite data set.

• Asia pacific journal of information systems
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• v.32 no.4
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• pp.890-915
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• 2022

Although existing studies on e-health have usually focused on e-health services adoption intention, there is a dearth of studies on the barriers that affect e-health services retention intention especially in India. Additionally, although studies have mostly focused on utilizing expectation-confirmation model to understand innovation related barriers, innovation resistance theory (IRT) has been overlooked. As Indian e-health service providers face stiff challenges due to customer's unwillingness to continue using the service, there is a need to bridge the research gap that exists in this context. This mixed-method study, based on responses received from 289 participants and 1154 online negative reviews from e-Health providers in India, examines the barriers from the IRT stance. Results of this study reveal a notable negative association between tradition, value and financial barrier and intention to continue using e-health services. Additionally, continuance intention affects recommendation. The study concludes with various implications and scope for future research.

• Atmosphere
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• v.27 no.3
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• pp.317-329
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• 2017

Ocean mixed layer (OML) depth affects diurnal cycle of sea surface temperature (SST) induced by change of solar radiation absorption and heat budget in ocean. The diurnal SST variation can lead to convection over the ocean, which can impact on localized precipitation both over coastal and inland. In this study, we investigate the OML characteristics affecting the diurnal cycle of SST for the Korean Peninsula and surrounding areas. To analyze OML characteristics, HYCOM oceanic mixed layer depth (MLD) and wind field at 10 m from ERA-interim during 2008~2016 are used. In the winter, MLD is deeply formed when the strong wind field is located on perpendicular to continental slope over deep seafloor areas. Besides, cooling SST-induced vertical mixing in OML is reinforced by dry cold air originated from Siberia. The OML in summer is shallowly distributed about 20 m. In order to estimate the impact of OML model in high resolution NWP model, four experimental simulations are performed. At this time, the prognostic scheme of skin SST is applied in NWP to simulate diurnal SST. The simulation results show that CNTL (off-OML) overestimates diurnal cycle of SST, while EXPs (on-OML) indicate similar results to observations. The prediction performance for precipitation of EXPs shows improvement compared with CNTL over coastal as well as inland. This results suggest that the application of the OML model in summer season can contribute to improving the prediction for performance of SST and precipitation over coastal area and inland.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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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.

• Journal of Korea Technology Innovation Society
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• v.18 no.1
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• pp.176-203
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• 2015

While the importance of adopting cloud computing service has been emerged, comparatively little research has been conducted on examining factors of an individual user's intention to switch toward cloud computing service. Hereafter, this study presents and empirically tests users' intention to switch to cloud computing. Our model posits that the characteristics of cloud computing such as effectiveness, economics, accessability, switching cost, security concern, and satisfaction toward existing IT service to cloud service affect perceived value, which in turn, influences intention to switch. An experimental study using student subjects provided empirical validation for our proposed model. Survey data from 204 respondents was used to test the model using partial least square analysis. As the result of the analysis, five hypotheses out of seven hypotheses were supported. According to our results, among the characteristics of cloud computing, effectiveness, economics, switching cost, and security concern were found to have significant impact on users' intention to switch that mediated by perceived value. Based on our research findings, we hope that this research will stimulate researchers' interest in the emerging area of cloud computing adoption.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.97-108
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• 2020

Nowadays, '1+N' is the operation model of compound bookstores. This study firstly investigated the general information and needs of customers and analyzed 4 basic behaviors of customers in 10 functional space of bookstore. Secondly, a preliminary analysis framework of interior design of compound bookstore was established, by applying 3 research tools of service design to 3 design elements of interior design. Thirdly, the case was analyzed in the preliminary analysis framework to find out the detailed process of the interaction between the customer and the bookstore, the touchpoint and the interior design project, to find out the blind spots in design, and put forward the solutions. Finally, after being refined, a compound bookstore interior design model based on the concept of service design was established. This model can be used to test the design content and service quality of the interior functional area of the compound bookstore, and to find out the design blank points.

• Journal of Information Technology and Architecture
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• v.10 no.4
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• pp.537-552
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• 2013

Software-as-a-Service (SaaS) has led to paradigm shifts in the information management area by combining it with SOA and Mashup. System developers now have more chances to access various high-quality functions through API opened on the web. But external resources are controlled by service providers so that it raises the component's uncertainty in system management which is related to external resources. In the cloud environment, components related to external resources causes negative effects on system's maintainability by making them dependant on service providers. This study proposes a way to enhance maintainability by using stable external resources. For this work, we suggest the N+1-tier model in which an external resource tier is added to the N-tier model. After that, we analyze how adding an external resource tier affects the decreasing complexity of maintainability and improving maintainability on web application.

• Journal of the Korean Society for information Management
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• v.22 no.4 s.58
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• pp.61-78
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• 2005

This study investigates the influences of the service qualify of public libraries, including printed publications, internet and electronic materials, culture programs and. service, library environment and facilities, and library staff, on the general satisfaction of the users, complaining intentions, and loyalty including reuse intentions. It develops a library user satisfaction model and testifies it through path analysis using questionnaires from 443 public library users in Daegu Metropolitan City area. This study shows that service qualities of printed publications, culture programs and service, library environment and facilities, and library staff Influence significantly on the general satisfaction of the users, and that service quality of library environment and facilities is the major variable which influences satisfaction and loyalty of the public library.