• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.213-216
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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 GMDSS ships and Non-GMDSS ships, increasing deceptive or false distress alerts generated by GMDSS installations, lack of understanding about the GMDSS 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.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.12
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• pp.455-462
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• 2014

In recent years, various services in mobile environments due to the growth of mobile devices and related techniques like wireless networks. Furthermore, as the increasing communication traffic in cellular networks has become a new significant issue, many studies for device-to-device(D2D) communication and D2D-based cooperative services have been performed recently. In this paper, we design a smart agent system for D2D-based cooperative services and propose a dynamic service binding method based on service ontology. We classify roles of mobile devices for cooperative services by defining three types of smart agents, and construct a knowledge base in order to describe properties of 'service' unit. The proposed knowledge model, D2D cooperative service ontology, can enable a autonomous cooperative services between mobile devices by binding a requested service to the appropriate member device according to the real-time context in mobile environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5A
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• pp.284-293
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• 2003

Location service is usually provided by the GPS method using satellites. In the next generation mobile communication systems which use smart antennas, location service can be accomplished using direction of arrival (DOA) estimation techniques. In this paper, we propose a DOA estimation technique for the location service of the next generation mobile communication systems and investigate the validity of the proposed technique through computer simulation. First, DOA estimation problems of distributed sources are considered using vortical and horizontal array processors which are orthogonal to each other. The DOA of the elevation angle is estimated by the vertical array processor and then that of the azimuth angle is estimated by the horizontal array processor. Finally, the procedures of the location service for specific signal sources using three smart antennas are exhibited by computer simulation to show that the proposed DOA estimation technique can be used for the location service in the next generation mobile communication systems.

• The Journal of the Korea institute of electronic communication sciences
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• v.1 no.1
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• pp.70-80
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• 2006

The large portion of communication service areas move from a legacy wire-line voice service to mobile data service. For the purpose of satisfaction on market need, many communication systems should be installed and upgraded based on a mobile wide-band transmission facility. Recently, large part of communication service is based on internet protocol by packet switch techniques and required new technologies such as multimedia processing, QoS achievement, and mobility managememobile communication network such as IS-95A/B and CDMA2000-1X. In this paper, I analyzed the network architecture and service provision methods. in CDMA2000-1X nt. In korea, a CDMA communication technique is standardized for digital mobile communication systems. By using the analysed results, I will extract an efficient method for network evolution and a core technique for next generation mobile communication network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2391-2398
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• 2011

National Information and Communication Services of Public Administration and Security organized by the 'A 'group (Line service network), 'B' group (IP service network), 'C' Group (Voice over Internet protocol(VoIP) service, IP application services) are provided by constructing the infrastructure. National Information and Communications Services 'C' group, providers are providing VoIP services. In this paper, national information and communications service 'C' group, providers of domestic calls, international calls, including calls to move we will study the basic telephone service. And text messaging, video telephony, IP-Centrex services, etc. we will study the seven value-added services. In addition, national information and communication service providers on the status of the project based on the analysis of national information and communication Internet telephone network using Internet telephony is the type of analysis. In this study, national information and communications services industry, will serve as the basis for the development.

• Journal of the Korean Society for information Management
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• v.31 no.3
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• pp.65-87
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• 2014

Organizational communication is an element of organizational structure formation; it is also a process of achieving organizational goals through the information sharing among the staff members in the organization as a social system. Organizational performance is a multidimensional concept composed of efficiency and effectiveness and satisfaction. Effectiveness implies service quality and the degree of goal achievement. Service quality by using the $LibQUAL+^{TM}$ model can be considered as an objective performance measure for libraries. This study aims to identify the effect of organizational communication in public libraries on service quality as a performance measure using the $LibQUAL+^{TM}$ model through statistical analyses of the results from questionnaire surveys of librarieans and users in 8 public libraries in Seoul metropolitan area. The result says the characteristics of organizational communication(upward, horizontal, downward communication) affects the three elements in the library service quality, such as affect of service, information control and library as place.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.6
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• pp.771-781
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• 1999

오늘날의 컴퓨팅 환경은 통신 네트워크의 복잡성과 다양한 멀티미디어 서비스 처리를 위해 객체지향 기술을 분산 시스템에 도입하고 통신망을 소프트웨어 계층적 모델로 구조화한 개방형 정보 통신망 구조 연구가 활발히 진행되고 있다. 본 논문은 분산환경에서 멀티미디어 스트림 데이타를 전송하기 위한 아키텍쳐에 관한 모델의 설계 및 구현에 관한 것으로 분산 환경에서 멀티미디어 스트림 데이타를 효율적으로 전송할 수 있는 구조를 제시하고 있다. 설계한 구조는 Point-to-Point와 멀티캐스트를 지원하며 컴퓨터 통신망에서 멀티캐스트 연결을 효율적으로 관리하고 추후 기능 확장 및 기능 변경이 용이하도록 모듈화하고 유연성을 가지는 연결 관리 구조를 설계하고 구현하였다. 신호기능은 CORBA(Common Object Request Broker Architecture)의 ORB를 이용하여 실현하였으며, 데이타 전송 기능은 TCP/IP연결을 이용하였다. 이렇게 신호처리 부분과 데이타 전송 부분을 독립적으로 만들어서 하부망 기술에 독립적인 연결 관리 구조를 채택하고 있으므로 향후 다른 환경에서도 신호처리 부분을 그대로 적용할 수 있다. 분산 객체 개념을 적용하여 연결 관리 기능을 분산 객체화 하였으며 각 분산 객체간 인터페이스를 OMG(Object Management Group) IDL(Interface Definition Language)로 정의함으로써 유연성을 갖도록 하였다.AbstractThis paper proposes communication service architecture to support dynamic communication configuration and multiple connection management which are required to handle a variety of multimedia multicast application. Our communication service architecture was designed to fulfil the objectives as the following:- To build a common networking system for various multimedia multicast services- To build a platform for rapid service development and provisioning- To provide service networking independent on transport network technologiesWe implemented communication service architecture based on Common Object Request Broker Architecture (CORBA) for multimedia multicast applications. Our communication service architecture is distributed and object-oriented for extensibility and easy modification. The interfaces between the distributed objects are specified in (Object Management Group) OMGs Interface Definition Language.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.42-46
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• 2012

This paper analyses technical and economical conditions which activate the use of mobile communication spectrum not to limit the growth of mobile broadband service because of mobile big data traffic and proposes the method which activate the use of mobile communication spectrum. To activate new mobile communication spectrum the expenditure and income of investment should be balanced. The activation of new mobile communication spectrum to process mobile big data traffic depends on technical and economical conditions, internal and external factors of service provider. The investment expenditure is relate to CAPEX, OPEX which is internal factors of service provider and to spectrum price which is external factor of service. The investment income is relate to tariff system which is internal factors of service provider and to spectrum neutrality which is external factor of service provider. The activation of new mobile communication spectrum can be implemented when the investment expenditure and investment income meet the balance including the spectrum price in the investment expenditure and the tariff system which is able to extend network and the income based on traffic increase by external contents in the investment income.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.5
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• pp.325-330
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• 2014

The era of convergence is being applied to all areas of Information and Communication Technology (ICT). The convergence of broadcasting service and communication service almost occurs on smart devices including smartphone. The smart hybrid Digital Multimedia Broadcasting (DMB) is a typical example of the convergence of broadcasting and wireless communication service. The hybrid mobile broadcasting service can support seamless video, 3D, high quality, and additional data services based on network connection between the broadcasting and wireless network. The gateway and terminal (including apps on the smartphone) take the role of the main components on the hybrid service. This paper presents the service concept, main components structure, the implementation of gateway and terminals, and field test to the urban areas for the mobile hybrid system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.321-326
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• 2015

Smart metering is one of the most implementable internet-of-thing service. In order to implement the smart metering, a wireless communication network should be newly designed and evaluated so as to satisfy quality-of-service of smart metering. In this paper, we consider a wireless network for the smart metering implemented with multi-purpose wireless chips and channel coding-functioned micro controllers. Especially, channel coding is newly adopted to improve successful frame transmission probability. Based on the successful frame transmission probability, average transmission delay and delay violation probability are analyzed. Using the analytical results, service coverage expansion is evaluated. Through the delay analysis, service feasibility can be verified. According to our results, channel coding needs not to be utilized to improve the delay performance if the smart metering service coverage is several tens of meters. However, if more coverage is required, chanel coding adoption definitely reduces the delay time and improve the service feasibility.