• Journal of Information Technology Services
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• v.8 no.1
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• pp.193-202
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• 2009

Cloud computing emerges as a new computing paradigm which targets reliable and customizable services. The term builds on decades of research in virtual machine, distributed and parallel computing, utility computing, and more recently networking, web service, and software as a service. In this paper, we provide a seamless connection migration of web services. This is useful for cloud computing environment in which many client terminals have mobility. With the wireless internet facility, those mobile users can move place to place during internet communication. Therefore, we provide solutions to the two major problems in current virtualization based migration: communication failure problems and connection re-establishment. Communication channel flushing by zero window notification helps to resolve the communication failure problems and TCP port inheritance prevents connection re-establishment errors during socket reconstruction. Thus, our web service migration facility is now able to preserve open network connections, and even for server sockets. This is a highly transparent approach, in that we did not Introduce additional messages for channel flushing and did not make any modification to the TCP protocol stack. Experimental results show that the overhead due to connection migration of web services is almost negligible when compared with time to take the conventional web service migration.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.309-316
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• 2016

Recently, the voice service over a mobile communication system tends to be provided based on the packet-based technology. Even though the sufficient transmission rate is supported by LTE mobile communication system, the quality of VoIP service that is experienced by the user can be degraded by the change in the transmission conditions and the terminal mobility. This paper has established an environment on which experiments are conducted for the different values of the major parameters that represent the transmission conditions. The result can contribute to the decision of the requirement that the mobile system should meet for maintaining the quality of VoIP service.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.1
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• pp.25-32
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• 2009

The advancements in the infusion of broadcasting and communication and the radio frequency identification technology have made the next generation mobile communication service technology be recognized as an important technology in many different fields and demanded systems of practical service using the technology. Designed in the study was a multimedia platform that would increase the utilization efficiency of limited frequency resources, which made an important part of the next generation mobile communication technology using the radio frequency identification technology, search for vacant frequencies not generating interfering signals to the old frequency users, and consider the growth of infused and complex services. In order to implement the platform, the investigator applied STI as a research model to maximize the functions of a service system and improve reliability. And also suggested IDMA of information required for platform building to maximize the functions of a service system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.324-327
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• 1996

In this paper, the affecting factors of the access demand for the cellular service are derived, and the access demand function of the cellular service is estimated. The results obtained in this study are as follows: First, the price (access charge) and the income elasticities of cellular services there exists a network externality in cellular communication services. Third, the technological capability of the service provider has played an essential role in expanding the size of subscribers. Fourth, the access demand of cellular communication service is not sensitive to the usage charge. According to the above results, it can be inferred that if the access charge is lowered, the number if subscribers will increase to the critical mass, and then the cellular communication market will grow up to a saturation point naturally.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.703-704
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• 2008

Multi-agent technologies are essential in realizing the upcoming ubiquitous environment. In the multi-agent environment, each agent has its own set of services and stores these services in the service repository of the multi-agent system. By using this repository, the user can retrieve the most appropriate service. In this paper, we propose an efficient service repository architecture that can improve the existing agent-based service discovery.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.116-130
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• 2012

Service provision and consumption platforms are more and more used to enable communication between sensors, actuators and intelligent devices, since they provide mechanisms that make possible the combination of components to create composed services. However, these kinds of platforms have limitations to adapt themselves to new and unknown devices. In this work we analyze the challenge of component or bundle communication by using the Open Services Gateway Initiative (OSGi) technology and we propose three mechanisms with the aim of contributing to flexible component communication: Common Service, Specific Service and WSIF Web Service Invocation. We provide these solutions with some architectural models and validate them through different example services. Finally we compare them regarding performance, flexibility and application complexity.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.187-193
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• 2010

This paper introduces a new mobile advertisement management system (AMS) utilizing on-line music service in communication networks. The developed AMS delivers commercial advertisement through music service that is preferred in communication networks, which enable advertisers to perform a customer based advertisement and listeners to get a discount on their bills for music service. And eventually the proposed AMS can provide the effective commercial service to the advertisers and the effective clients recruit ways to music providers.

• The Journal of Korean Academic Society of Nursing Education
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• v.22 no.4
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• pp.559-566
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• 2016

Purpose: This study aimed to examine the communication styles and nursing service satisfaction of clinical research nurses perceived by clinical subjects. Methods: The data were collected with self-administrated questionnaires after receiving consents from 200 clinical trial subjects. The data were analysed with descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients and stepwise multiple regression analysis using SPSS 21.0 statistic program. Result: Clinical subjects perceived that clinical research nurses used the informative, affective, and non-authoritative communication styles. The study identified factors influencing the nursing service satisfaction, and they were the informative communication styles (${\beta}$=.34, p<.001) and affective communication styles (${\beta}$=.35, p<.001, $R^2$=37%) by multiple linear regression. Conclusion: If educational programs on communication are developed to help clinical research nurses use the informative and affective communication styles according to the characteristics of subjects and applied to the field of practice, they will be able to increase the nursing service satisfaction and contribute to the higher quality of clinical trials.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.733-738
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• 2005

The distress communication system in the maritime mobile service had almost depended on the wireless telephony or telegraphy technique. The GMDSS (Global Maritime Distress and Safety System) which was introduced in 1992 brought a lot of changes in the maritime distress communication service such as the automatic transmission of distress signals and implementation of global search and rescue networks. However, there are some deficiencies in the GMDSS distress communication system such as a lack of compatibility in the maritime distress communication between CMDSS ships and Non-GMDSS ships, increasing deceptive or false distress alerts generated by GMDSS installations, lack of understanding about the CMDSS installations for the operators. In this paper, the problems of distress communication system in the maritime mobile service are analyzed and the methods to solve or minimize these problems are suggested.

• Journal of Digital Convergence
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• v.10 no.3
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• pp.265-271
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• 2012

This paper proposes a communication distance performance evaluation method for mobility of service robots equipped with a Wi-Fi module. Service robots have function of mobile communication system according to classified services and utilize a (preferred) communication method, wireless lan(IEEE802.11 a/b/gin) communication method of ISM band(2.4GHz and 5.8GHz). For evaluating degradation performance of wireless data for the service robot's mobility. We measured and presented reference vectors obtained by utilizing a distance attenuation correlation method in the real world environment. To evaluate performance of the proposed method, path loss of reference vectors was assigned to the Azimuth 301W and then transmission rate and the transmit throughput of the test sample were measured by the Chariot. The proposed measurement method is necessary for securing wireless LAN communication distance for mobility of mobile smart device and service robots. In addition, if the proposed measurement method os adopted, It would be expected that mobile smart device vendors would utilize the method as an effective wireless LAN mobility communication distance performance evaluation method.