• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.146-153
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• 2009

Recently, the research relative to NGN(Next Generation Network) is progressing in 3GPP(The 3rd Generation Partnership Progect), IETF(Internet Engineering Task Force), and so on. Although user needs frequently mobility which is various service pattern, In accordance with the development of these various applications, IMS(IP Multimedia Subsystem) and hierarchical networks ie, Femtocell/WiBro/3G etc is constructed for more user demands which provide service in anytime, anywhere. It is necessary to optimum network selection criterion which consider to wireless signal quality add to user service profile and service network traffic balance. NGN also needs a method to perform heterogeneous handover and to constraint Ping-pong phenomenon when using existing terminal-based handover decision. This paper proposes scheme for network selection and heterogeneous handover procedure in hierarchical wireless multi-access network based on SIP-MIH(Session Initiation Protocol-Media Independent Handover) with IMS by using user service profile that the considerations are dealing with not only selection and registration of various access network but also easy of developing the terminal.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.5
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• pp.209-217
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• 2012

In the present, Wireless Sensor Network(WSN) has been used for the purpose of the military operation with surveillance systems and for collecting useful information from the natural environment. Basically, low-power, easy deployment and low cost are the most important factors to be deployed for WSNs. Lots of researches have been studied to meet those requirements, especially on the node capacity and battery lifetime improvements. Recently, the study of wireless mesh networks applied into the surveillance systems has been proceeded as a solution of easy deployment. In this paper, we proposed large-scale intelligent multi-layer surveillance systems based on QoS assuring Wireless Mesh Networks and implemented them in the real testbed environment. The proposed system explains functions and operations for each subsystem as well as S/W and H/W architectures. Experimental results are shown for the implemented subsystems and the performance is satisfactory for the surveillance system. We can identify the possibility of the implemented multi-layer surveillance system to be used in practice.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.7
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• pp.688-696
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• 2000

A scheme for fault detection on the subsystem level is presented. The method uses analytical redundancy and consists in generating residuals by comparing each measurement with an estimate computed from the reference models. In this study regression neural network models are used as reference models. The regression neural network is memory-based feed forward network that provides estimates of continuous variables. The simulation result demonstrated that the proposed method can effectively detect faults in an air handling unit(AHU). The results show that the regression models are accurate and reliable estimators of the highly nonlinear and complex AHU.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.36-45
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• 2000

Automated production system is composed of many complicated techniques and it become a very difficult task to control, monitor and diagnose this compound system. Moreover, it is required to develop an effective diagnosing technique and reduce the diagnosing time while operating the system in parallel under many faults occurring concurrently. This study develops a Modular Artificial Neural Network(MANN) which can perform a diagnosing function of multiple faults with the following steps: 1) Modularizing a complicated system into subsystems. 2) Formulating a hierarchical structure by dividing the subsystem into many detailed elements. 3) Planting an artificial neural network into hierarchical module. The system developed is implemented on workstation platform with $X-Windows^{(r)}$ which provides multi-process, multi-tasking and IPC facilities for visualization of transaction, by applying the software written in $ANSI-C^{(r)}$ together with $MOTIF^{(r)}$ on the fault diagnosis of PI feedback controller reactor. It can be used as a simple stepping stone towards a perfect multiple diagnosing system covering with various industrial applications, and further provides an economical approach to prevent a disastrous failure of huge complicated systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.511-514
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• 1998

본 논문은 대용량 통신처리 시스템의 프레임 릴레이망 접속을 통한 인터넷 접속 서비스 기능을 제공하는 프레임 릴레이망 정합 서브 시스템(FNAS : Frame relay Network Access Subsystem)의 설계구조 및 구현사항에 대하여 기술한다. 프레임 릴레이망 정합 서브 시스템은 대용량 통신처리 시스템에 연결되어 전화망(PSTN) 또는 종합 정보통신망(ISDN) 사용자 단말기에 PPP접속기능을 제공하여 프레임 릴레이망에 접속되어 있는 ISP나 CP의 접속을 통한 인터넷 접속 서비스를 제공하거나 정보 제공자(Information Provider)의 DB를 검색하도록 개발하였다.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.380-383
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• 2009

QOOK 인터넷전화는 BcN(Broadband Convergence Network) IMS(IP Multimedia Subsystem)기반으로 음성/영상 전화를 제공한다. 본 논문에서 소개하는 QOOK 부가서비스인 한글로서비스는 인터넷 전화기를 이용하여 착신자 전화번호를 눌러 발,착신자간에 통화가 이루어지는 것이 아니라 전화번호를 모르더라도 한글이름을 입력하여 발,착신자간에 통화가 이루어지는 서비스이다. 본 논문은 일반 전화번호기반의 통화서비스에서 진화되어 전화번호가 아닌 한글이름을 이용하여 발신, 착신을 위한 BcN_소프트스위치, 응용서버 등에서 입력된 이름을 처리하는 기능을 소개한다.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.325-333
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• 2014

An ADS-B system, which is a critical technology in surveillance area of the CNS/ATM, can replace or compensate a conventional radar based surveillance system through the communications among aircrafts. An ADS-B ground system which is to use the ADS-B on the ground air traffic management system consists of various subsystem devices such as ground stations that communicate with the aircrafts, and ADS-B/TIS-B/FIS-B servers. The ADS-B ground system has a form of distributed system and is interconnected through the network. Therefore, a system which can monitor and control the status of the multiple subsystem devices of the ADS-B ground system is essential. In this paper, we designed and implemented a remote status monitor and control system for the ADS-B system that can monitor and control the subsystem devices of the ADS-B system in remote place via SNMP protocol.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.798-804
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• 2009

A high-resolution electro-optical camera system, EOS-C, is under development in Satrec Initiative. This system is the mission payload of a 400-kg Earth observation satellite. We designed this system to give improved opto-mechanical and thermal performance compared with a similar camera system to be flown on the DubaiSat-1 system. The thermal control subsystem (TCS) of the EOS-C system uses heaters to meet the opto-mechanical requirements during in-orbit operation and it uses different thermal coating materials and multi-layer insulation (MLI) blankets to minimize the heater power consumption. We performed its thermal analysis for the mission orbit using a thermal analysis model and the result shows that its TCS satisfies the design requirements.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.99-104
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• 2015

Service platform which can offer various multimedia communication as the video, audio, voice and data is IMS(IP Multi-Media Subsystem). It is effective in the company is introducing only such convergence IMS services to be required to provide various multimedia services at the lowest cost and existing communication environment while keeping the maximum Therefore, in this study, we had developed IMS 코어 main system that not more than 1,000 employees of companies can effectively establish IMS solutions. This system is located at the middle between IMS terminal and CSCF(Call Session Control Function) in line with IMS services and provides CSCF in response to the IMS terminal and IMS terminal in response to the CSCF. As well, corded telephone and SIP phone which were used as terminal is linked with gateway.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.166-178
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• 2000

As the 21st century signifies an information-oriented society, the computer integration takes place in all walks of human presence. Needs for computer and network-integrated automation present new challenges in military as well as commercial facility systems engineering. Since the first intelligent building appeared in USA in 1984, it gradually became an essential capability for the building industry requirement these days. Intelligent Building System(IBS) is evolving to be very complex because there are many subsystems such as telecommunication(TC), office automation(OA), building automation(BA), security, construction environments, etc. During the planing phase of IBS development, therefore, a disciplined systems engineering must be performed to analyze stake- holder's requirements to build an optimized system while minimizing trial-and-error expenses and risks. This paper presents a conceptual design of BAS applying systems engineering methods. The contribution of this study includes the development of IBS subsystem specification for building automation subsystem, which is a part of IBS, using the methodology of requirement analysis, functional analysis, synthesis, and verification. A computer-aided systems engineering s/w, RDD-100, was used to improve the system design efficiency and to promote the product design knowledge management for reuse in later design programs.