• Journal of KIISE:Information Networking
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• v.36 no.4
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• pp.360-368
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• 2009

Recently, broadband access networks have been competitively deployed all over the world with the development of various multimedia services for such a network. ETRI(Electronics and Telecommunications Research Institute) built the FTTH(Fiber-To-the-Home) service center to develop a next-generation equipment and a high-quality service/platform as well as to promote domestic industry in the field of optical communication. The FTTH service center has a variety of test equipments such as FTTH standard testbed for a BMT(bench mark test), a network operation center, and IPTV service equipments. Also, ETRI deployed a new type of commercial optical access networks cooperating with ISP(Internet Service Provider). This paper presents the performance evaluation of FTTH E-PON(Ethernet Passive Optical Network) system as a platform for TPS(Triple Play Service) based on QoS(Quality of Service) and QoE(Quality of Expericence) issues. This FTTH E-PON system is successfully demonstrated as an optical access network system by commercial network service provider and the FTTH service center of ETRI.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.522-525
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• 2018

In this paper, we design a UWB / WAS microstrip antenna for wireless local high - speed communication. The substrate of the proposed antenna is FR-4 (er = 4.3) and its size is $30[mm]{\times}30[mm]$. It is designed to have characteristics that can be used in the frequency bands of 3.5 [GHz] and 5.2 [GHz], which are UWB / WAS frequency bands. The simulation was performed using CST Microwave Studio 2014. Simulation results show that the gain is 1.592 [dBi] at 3.5 [GHz] and 2.210 [dBi] at 5.2 [GHz]. The S-parameter also showed a result of less than -10 [dB] (WSWR 2: 1) in the desired frequency band. Microstrip antennas have been miniaturized, high performance, and light weight, and excellent and low cost systems are continuously being developed. In addition, many people use wireless local area network systems used in homes, companies, and public facilities. Since the UWB / WAS technology is proposed according to the development of the system and the demand increase, the antenna that satisfies the above conditions will be designed and the technology applicable to the system will be used more conveniently.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.795-804
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• 2009

An HSS(Home Subscriber Server) system requires a main-memory database on main-memory unit for the real-tine management of the subscriber information in the mobile communication service, in that the system controls not only basic data for handling calls of users, but also additional service data related to user authentication and operational data. Nonetheless, HSS-DBS system, requiring the reliability and stability, need more secure data store method and a back-up technique because the system have a long startup time and the big problem on the failures of main-memory. This paper proposes an efficient back-up replication technique, on the basis of enhancing the stability and performance of HSS system. The proposed shadowing back-up technique adopting the delayed recovery process, can help minimize the real-time back-up overloads by location registration, while the proposed backup replication method enables more stable system operations with replicating the data to remote server in real time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.209-214
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• 2014

IMS(IP Multi-Media Subsystem) is in the limelight as the Integrated wire and wireless Systems because of a sudden increase of smart mobile devices and growth of multimedia additional services such as IPTV. The structure of IMS is designed as a session control layer to provide various multimedia summative service using SIP based on IP communication network in order to carry out set-up, change and release by NGN of course, the existing voice services. But now It is broadly substituting in the IPTV, wire phone company and it is substituted in internet platform base on the soft-switch in currently. Especially, in currently, 4G LTE in a mobile communication company is rapidly growing in market. Therefore, in this study, we had designed and developed to the main prosser that can admit to 1000 user over and SIP gateway which can link the IMS Core that can link SIP Device which adopt the standard protocol on the SIP and to provide variable multimedia services.

• Composites Research
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• v.16 no.2
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• pp.26-32
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• 2003

Optical fibers, for splice, are stripped of their plastic coatings with a plastic stripper and cut off at the end. Therefore, stripped fibers often receive accidental damages and sustain small flaws or cracks. As a result, the breaking strength of a fiber splice made under normal conditions is reduced to about 0.4∼1 ㎏ on the average, nearly one-tenth of the fiber's strength. This makes it necessary to reinforce the splice. One of the most practical and reliable methods for optical fiber splicing is fusion splicing, comprising the steps of tripping the plastic coatings from the two fiber ends to be splice, placing the two bare fiber ends in an end-to-end position, and of fusion splicing, such as are fusion. Generally, steel bar (SB) sleeve is used to reinforce this fusion-splicing region. However, this type of sleeve has a critical defect to keep optical lose after bent by a sudden load. New type of composite spring (CS) sleeve is developed to make up for the weak points in the SB sleeve. This sleeve has an effect on restoration to the original state after eliminating the bending load. The optical spectrum analyzes results show the availability of reinforcement for the fusion splicing optical fiber using small diameter composite springs under the various loading conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.2
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• pp.108-121
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• 1986

In this paper, the development of a simulator for the performance estimation and parameter optimization of an integrates voice/data packet communication network is described. The simulator implemented is capable of simulating the integrated voice/data network that handles packet voice terminals as well as data terminals and hosts operating under standard CCITT protocols. Of the three descrete event simulation approaches presently known, the process interaction method has been chose. With this approach one can implement a simulator that is related most Closely with the real system. The simulator has been implemented in PL/I and GPSS simulation languages, resulting in a software package of about 4,000 lines. To reduce the computer run time of the simulator, we have used a method of reducing conditional events based on a GPSS LINK block. We describe various aspects of the simulation model developed. We then investigate the performance of a 7-node network using the simulator, and present the results. For validation of the simulator developed, we construct a simulation model for a simple voice/ data multiplexer, and compare the results of simulation with those of an analytical model.

• The KIPS Transactions:PartD
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• v.9D no.4
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• pp.667-676
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• 2002

Digital environment that is represented to Internet is displacing business way of industry and business achievement way with the fast speed being giving great change on life whole. Improve existent business process utilizing Internet and Web connection technology, information superhighway to tradition industrialist manufacturer and e-Transformation's propulsion that wish to maximize productivity and administration efficiency is spread vigorously. In this paper, administration efficiency raising of Web-based factory monitoring system to do monitoring when everywhere integrating operation present condition current point of time of discrete factories in inside and outside of the country by purpose design and implemented. That is, do to normalize system structure and achievement function, and administration data of Web-based, and design using VML (Unified Modeling Language) and take advantage of ASP (Active Server Pages) and implemented web function. Implemented Web-based factory monitoring system is applying two factory (Kl, K2) of K CO., LTD. tire operation division to caravan, and application result was evaluated by very efficient thing to grasp operation situation of whole factory synthetically.

• Smart Media Journal
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• v.7 no.4
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• pp.52-60
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• 2018

Energy Management System(EMS) of Microgrid(MG) collects and analyzes data from devices in the microgrid to provide information to operators, users and other systems. In the middle of the process, it is required to securely provide information through both wired and wireless communication networks. In this paper, we design and implement a module that provides encryption and decryption, key management, key distribution, and message authentication functions, thus enabling the development of a system which is safe from the exposure and modulation of data potentially occurrable during data transmission between RTU(Remote Terminal Unit) and EMS. Our method can increase the efficiency of connection and key management for RTU by connecting a virtual device(VD) to RTU.

• Journal of IKEEE
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• v.23 no.3
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• pp.777-784
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• 2019

A pre-fire awareness and automatic notification system are required because it is possible to minimize the damage if the fire situation is precisely detected after a fire occurs in a place where people are unusual or in a mountainous area. In this study, we developed a RaspberryPi-based fire recognition system using Faster-recurrent convolutional neural network (F-RCNN) and single shot multibox detector (SSD) and demonstrated a fire alarm system that works with power line communication. Image recognition was performed with a pie camera of RaspberryPi, and the detected fire image was transmitted to a monitoring PC through an inductive power line communication network. The frame rate per second (fps) for each learning model was 0.05 fps for Faster-RCNN and 1.4 fps for SSD. SSD was 28 times faster than F-RCNN.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.565-573
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• 2022

Current mobile communication system is in the mid-process of conversion from 4G LTE to 5G network. According to the generalization of mobile communication services, personal information such as user's identifiers and location information is transmitted through a mobile communication network. The importance of security technology is growing according to the characteristics of wireless mobile communication networks, the use of wireless shared channels is inevitable, and security technology cannot be applied to all network system elements in order to satisfy the bandwidth and speed requirements. In particular, for security threat analysis, researches are being conducted on various attack types and vulnerability analysis through rogue base stations or attacker UE to make user services impossible in the case of 5G networks. In this paper, we established a 5G network testbed using open sources. And we analyzed three security vulnerabilities related to NAS COUNT and confirmed the validity of two vulnerabilities based on the testbed or analyzing the 3GPP standard.