• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.29-54
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• 2012

This study aims to grasp what factors affect users' recognition level and expectation level for library service, being offered at the library of Korea National Open University. Also, this study seeks to conduct a survey and analyze whether users' recognition level by library service dimensions has actually influenced the intention and the satisfaction with using the library. For this, it carried out the theoretical approach, which considers domestic and foreign documents on evaluation of quality of library service, and the empirical approach of questionnaire research and analysis. A research model was designed on the basis of LibQUAL+model to achieve the objective of this research. And the group-based difference was confirmed by carrying out verification on research hypothesis. As a result of analysis, the users' current recognition level by library service dimensions of Korea National Open University was indicated to have influence on the whole satisfaction with library and the continuous use intention. The whole satisfaction was indicated to have an effect on continuous use intention. Also, to enhance users' satisfaction level according to the behavioral characteristics of using library, the core elements for improving the library service of Korea National Open University were cited and these include improving the facility of library, implementing smart digital library system for offering remotely academic information, and securing diversity and currency of academic information sources such as printing materials and electronic materials.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.159-164
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• 2017

Existing employment information system is the result of a number of lists list exists is difficult to determine at a glance when a user searches for a desired jobs. The service used for the strengthening and enhancement of job satisfaction, job seekers in the problems of the existing system, there is a need to improve measures for improving the quality of the environment. In this paper, we developed a system using a mashup Jobs feature that allows users to easily and conveniently search the various regions, the conditions specific jobs you want on the web map. In this paper, we collect the RSS of employment related information from many employment information providers, and we have a mashup function that makes it easy and convenient to search various regional and conditional job information desired by the user on the web map I have developed a job information system that I used.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.84-93
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• 2011

In order to provide the real time and proper information to the pedestrian who is using the transport connection and transfer center through data collecting and processing process, the design of the test-bed (Gimpo airport)'s communication construction and the technology of the pedestrian location tracking has been researched. The design of the communication construction should make sure that it can provide believable data to the user of the transfer center. At the same time, the location tracking should also be considered, so that the require of the communication efficiency and the location tracking efficiency can be met together. In order to make the efficient location tracking technology, the problems related to the commercial technology based real time location identification will be resolved and the new approach method was proposed and be applied and analysed to the test-bed. The wireless access points can be located in the most real-world situation which has added the characteristics of the real building to the electronic map, and through the analysis of theirs location, they can be set as the mainly necessary points for the communication construction design and the location tracking and the method to locate that points has been proposed. How to set, how to apply it to the test-bed and the examination result will be introduced in this paper.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.51-55
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• 2006

Digital satellite communication systems are usually integrated with terrestrial systems to provide various services. In these cases, they should satisfy the performance objectives defined by the terrestrial systems. Recommendation ITU-R S.1062 specifies the error performance objectives of digital satellite communication systems operating below 15 GHz. The error performance are given in terms of bit error probability divided by the number of the average bit errors in the burst ($\alpha$). This paper presents a theoretical method to estimate $\alpha$ that is a very important parameter in the satellite communication systems to analyze the error performance objectives. We show performance estimation result of DVB-RCS turbo code using the presented method, and verify them by comparing to the simulation results.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.10-15
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• 2007

Small size and low profile antenna for mobile vehicular-top-mounted is needed in satellite communication services such as DBS, Satellite Internet and VSAT. In middle latitudes, the development of an array antenna which has the conformal, low profile and 45 degree beam tilted configuration, and has the high gain with sharp beamwidth, low sidelobe and low loss is required for Ku-band satellite communication. In this paper, in order to meet with these performances, an array antenna consisting of the vertical polarized waveguide longitudinal slots based on the leaky-wave mode of traveling wave antenna is proposed. An array antenna consisting of 16 leaky-wave elements is showing 30 dBi of gain, 4.9 degree of beamwidth, below than -20 dB of sidelobe level, 45 degree of beam tilt angle in center frequency. Feed network designed by waveguide cooperated feed shows good performance of wideband and low loss.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.2
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• pp.69-77
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• 2009

Small size and low profile antenna for mobile vehicular-top-mounted is needed in satellite communication services such as DBS, Satellite Internet and VSAT. In middle latitudes, the development of an array antenna which has the conformal, low profile and 45 degree beam tilted configuration, and has the high gain with sharp beamwidth, low sidelobe and low loss is required for Ka band satellite communication. In this paper, in order to meet with these performances, an array antenna consisting of the vertical polarized waveguide longitudinal slots based on the leaky-wave mode of traveling wave antenna is proposed. Especially, for the lower sidelobe level the radiation power control using a design method of the different slot width is proposed. An array antenna consisting of 32 leakywave elements is showing 34.4 dBi of gain, 3.6 degree of beamwidth, below than -25 dB of sidelobe level, 43 degree of beam tilt angle in center frequency 20.0 GHz. Feed network designed by waveguide cooperated feed shows good performance of wideband and low loss.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.6
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• pp.281-288
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• 2017

In Smart-cities, various types of integrated services must be linked to provide services to applications. Therefore, flexibility must be ensured between services so that various services can be efficiently provided. In order to secure the flexibility among services, it is very important to have a function to dynamically discover and invoke a desired service by searching for a semantic service by reflecting a recognized context through real-time context-aware in smart-cities. To date, quite a number of semantic service discovery techniques have been developed. However, they have not been verified as suitable for use in the smart-city domain. In this study, we tried to verify the existing ones to use a suitable one. We tested most of existing semantic service discovery techniques, but we found that none of them is suitable to our research. Therefore, we developed our own semantic service discovery technique. This paper introduces our work and presents the performance evaluation results that demonstrate that our developed works well and show good performance. For the performance evaluation, the experimental system was actually constructed and the real performance was measured. In the experiment, we implemented the semantic service discovery scenario that dynamically searches and calls the services needed to provide fire accident management services in smart cities.

• Journal of Satellite, Information and Communications
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• v.10 no.1
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• pp.33-43
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• 2015

This study, by using SNS, is to find ways to improve the recognition of the audience on creative musical for performance planning and marketing after looking into how the choice attributes of creative musical has the different impact on satisfaction. As a result, the audiences who use SNS show that the composition of content(1st ranking), main actors(2nd ranking), reviews on musical(3rd raking), and production(4th ranking) have the impact on their satisfaction but the stage composition, staff service, satisfaction on theater, and admission fee haven't. For those who don't use SNS, however, the composition of content(1st ranking), reviews on musical(2nd ranking), production(3rd raking), and main actors(4th ranking) affect the satisfaction while the staff service, stage composition, admission fee, satisfaction on theater hardly make any effect on it.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.12
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• pp.437-444
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• 2022

Recently, research on mobile edge services has been conducted to handle computationally intensive and latency-sensitive tasks occurring in wireless networks. However, MEC, which is fixed on the ground, cannot flexibly cope with situations where task processing requests increase sharply, such as commuting time. To solve this problem, a technology that provides edge services using UAVs (Unmanned Aerial Vehicles) has emerged. Unlike ground MEC servers, UAVs have limited battery capacity, so it is necessary to optimize energy efficiency through load balancing between UAV MEC servers. Therefore, in this paper, we propose a load balancing technique with consideration of the energy state of UAVs and the mobility of vehicles. The proposed technique is composed of task offloading scheme using genetic algorithm and task migration scheme using Q-learning. To evaluate the performance of the proposed technique, experiments were conducted with varying mobility speed and number of vehicles, and performance was analyzed in terms of load variance, energy consumption, communication overhead, and delay constraint satisfaction rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1055-1063
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• 2002

In this paper, we have studied path selection problem using multiple metric. Current Internet selects a path using only one metric. The path selected by one metric is a best-effort service that can satisfy one requirements. In order to satisfy a call with various Qualify-of-Service(QoS) requirements, the path must satisfy multiple constraints. In many cases, path selection is NP-complete. The proposed algorithm is widest-least cost routing algorithm that selects a path based on cost metric which is basically a delay metric influenced by the network status. The proposed algorithm is a multiple metric path selection algorithm that has traffic distribution ability to select shortest path when network load is light and move traffic to other alternate path when the link load is high. We have compared the results with other routing algorithms.