• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.189-193
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• 2010

SIP 프로토콜 기반 VoIP 서비스는 편리함과 저렴한 통신비용으로 사용자 수가 급증하고 있다. 하지만 Text 형태의 SIP 헤더 정보를 UDP 방식으로 전송하기 때문에 손쉽게 위변조 할 수 있으며, 최근 SIP를 통해 제공되는 다양한 형태의 부가서비스에 대한 보안 위협이 증가하고 있다. FMC 폰을 통해 제공되는 동시착신, 착신전환, 3인통화 등과 같은 부가서비스에 대한 공격을 통해 과금우회 공격 등을 수행할 수 있다. 따라서 본 연구에서는 FMC 환경에서 제공되는 주요 SIP 부가서비스를 대상으로 각각의 취약성에 대해 조사 분석하였으며, 분석된 내용을 중심으로 SIP 기반 인터넷전화 부가서비스에 대한 공격 시나리오를 단계별로 설계 및 개발하였다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.3
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• pp.492-503
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• 1994

In this study, the control and scheduling of the flexible manufacturing cell (FMC) is discussed, which can perform the mixed production and relieve the effect of machine failure. The control of the FMC isvery complex task due to the property of multiple jobs and the dynamically changing states. For effective control of proposed FMC, the hierarchical scheme is introduced and the functions of each levels are defined. Especially for the control functions of shop floor level and cell level, the intelligent scheduler is implemented. To show the efficiency of the intelligent scheduler, the production method fo the existing assembly lines was evaluated and compared with the proposed intelligent FMC method. The results from the production performance show that the proposed method is superior to the existing method in various performance indices.

• Journal of the Korea Society of Computer and Information
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• v.4 no.3
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• pp.13-19
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• 1999

In this paper, we suggests a WIP (Work In Process) of FMC (Flexible Manufacturing Cell) analysis methods based on the TPN (Time Petri Nets) unfolding. Unfolding of PN is a partial order-based method for the verification of concurrent system without the state space explosion. The aim of this work is to formulate the general cyclic state scheduling problem to minimize the WIP to satisfy economical constraints. The method is based on unfolding of the original net into the equivalent acyclic description.

• Journal of the Korea Society for Simulation
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• v.1 no.1
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• pp.55-63
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• 1992

This paper presents a simulation based analysis of a service robot operating in a robot-centered FMC, in which the robot is located at the approximate center of the cell and the machines are arranged in a partial circle around it. The robot's function is to locate and service the parts which require a series of unloading, moving, and loading operations. The main purpose of the analysis is to determine the best movement decision for the robot's arm in each instance. The results from the study, based on both statistical and nonstatistical analysis suggest the best policy for the robot's arm's movement that holds promise for application to the robot-centeredFMC.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.28-28
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• 1992

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.273-274
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• 2010

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.99-103
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• 2009

Recently, as wired and wireless communication services have rapidly developed and multimodal mobile devices which have various characteristics have widely spread, the need for new convergence services increases. The growing population of VoIP technologies and the high communication expense yield that the market of IP based telephony such as WiFi phone and IP phone is substituted for one of the conventional PSTN telephony. With the help of this trend, the wireline network operators desire to find a market in mobile networks. Therefore, they focus on Fixed Mobile Convergence (FMC) service as one of the key factors to accomplish this goal. FMC services are able to provide the mobility of voice services between circuit switched and packet switched networks. IP Multimedia Subsystem (IMS) based Voice Call Continuity (VCC) is one of the schemes to embody FMC services. As Application Server (AS) which has this VCC function provides seamless handover of services between heterogeneous networks, FMC subscribers can communicate seamlessly with others m WiFi domain and COMA domain using WiFi-COMA dual phone. Most of enterprises have already introduced IP network infrastructure and IP-PBX (Private Branch eXchange) for telephony. However, the problems of high communication cost and work inefficiency due to frequent outside jobs or business trips have remained. In order to solve these problems, demands for enterprise FMC services increase. In this paper, we introduce a new IP-PBX based VCC model that can provide seamless handover of voice services between WiFi and COMA networks for enterprise users and we investigate some interworking and security issues between Soft Switch (SSW) and IMS, or between IMSs. In addition, we introduce a new service that can provide the continuity of voice sessions as well as video sessions using Multimedia Session Continuity (MMSC) technology which has evolved from VCC. This service is expected to be one of the next-generation personalized services based on user's context.

• 정보화사회
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• s.182
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• pp.6-7
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• 2006

유무선 통합 서비스가 통신 업계를 뒤흔들고 있다. 오래 전부터 소리 소문 없이 유무선 통합 서비스 논의는 계속 있어 왔지만, 올해들어 본격적인 도입 움직임이 일고 있다. 영국 BT를 시작으로 프랑스텔레콤이 불을 당겨 유럽은 이미 FMC 중심에 위치했다. 국내에서도 LG텔레콤의 '기분존' 서비스가 인기를 누리면서 FMC에대한 관심이 부쩍 높아졌다. 이에 따라 단말기 업체들도 시장 선점을 위해 잇따라 제품을 선보이고 있다. 바야흐로 유선과 무선의 경계가 허물어지고 있는 것이다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.503-503
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• 1995

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.529-534
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• 2005

In this paper, a new type of output feedback control, called a $H_2/H_{\infty}$ fnite memory control (FMC), is proposed for deterministic state space systems. Constraints such as linearity, unbiasedness property, and finite memory structure with respect to an input and an output are required in advance to design $H_2/H_{\infty}$ FMC in addition to the performance criteria in both $H_2$ and $H_{\infty}$ sense. It is shown that $H_2$, $H_{\infty}$, and mixed $H_2/H_{\infty}$ FMC design problems can be converted into convex programming problems written in terms of linear matrix inequalities (LMIs) with some linear equality constraints. Through simulation study, it is illustrated that the proposed $H_2/H_{\infty}$ FMC is more robust against uncertainties and faster in convergence than the existing $H_2/H_{\infty}$ output feedback control schemes.