• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.713-718
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• 2007

Structural tests often involve a large amount of complicated information. Data models can be used to efficiently organize the information. This paper briefly describes a data model for structural tests including hybrid tests, performed by the Real-Time Multi-Directional (RTMD) facility at the ATLSS Center of Lehigh University in America. The RTMD facility is an equipment site within the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES). The data model is called the Lehigh Model. An overview of classes and attributes of the Lehigh Model is presented, and the Lehigh Model is compared with other data models to show its benefits for structural testing.

• Journal of Korean Association for Spatial Structures
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• v.19 no.4
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• pp.103-110
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• 2019

The cable-based retractable membrane roof makes it impossible to maintain its shape and stiffness during driving process, unlike the hard-type retractable roof. Consequently, monitoring using a relatively simple wireless video transmission device is required. However, since video data has a bigger transmission rating than other monitoring data in terms of the structure velocity or acceleration, there is a need to develop transmission device that is easy to install and entails low maintenance cost. This paper studies on a real-time video transmission system for monitoring the cable-based retractable membrane roof while driving. A video transfer software, using the mobile network, is designed and the embedded system is constructed. Ultimately, the data transmission server is tested. Connecting a trolley to the system allows testing of the validity and efficiency of the developed system through the video data transmitted in the driving process. Result of the test shows that the developed system enables multi-device data transfer with monitoring via the mobile network.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.30-34
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• 2005

Due to old Toshiba EMS's database size limit and hardware old aging, KPX(Korea Power Exchange) had introduced New EMS from AREVA(old ALSTOM) in July 2002. After then KPX had committed many man power and time to normalize EMS NA(Network Analysis) functions for using real power system. At initial stage, to normalize State Estimator which is the backbone of all other NA functions and DTS(Dispatcher Training Simulator}, KPX had corrected numerous topology errors, network model errors, non-scanned and wrongly scanned SCADA measured errors. After SE function study, running test and tuning, State Estimator could finally have been run properly and stably from June 2003. Based on SE running, KPX had normalized real time Contingency Analysis, and study mode Power Flow, STNET and DTS. From early 2004, dispatchers have been trained to use NA and DTS for the purpose of stable SE running, NA operation & results reading and urgent equipment outage reviewing. EMS NA have been greatly contributed to operate real time power system stably. Above NA normal operation by KPX own efforts under the no experience of NA running, KPX made a good precedent. This paper is intended to introduce EMS NA normalization process, operation status, and etc in Korea power system operation.

• KIEE International Transactions on Power Engineering
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• v.3A no.4
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• pp.191-197
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• 2003

Accurate detection and classification of faults on transmission lines is vitally important. In this respect, many different types of faults occur, such as inter alia low impedance faults (LIF) and high impedance faults (HIF). The latter in particular pose difficulties for the commonly employed conventional overcurrent and distance relays, and if undetected, can cause damage to expensive equipment, threaten life and cause fire hazards. Although HIFs are far less common than LIFs, it is imperative that any protection device should be able to satisfactorily deal with both HIFs and LIFs. Because of the randomness and asymmetric characteristics of HIFs, their modeling is difficult and numerous papers relating to various HIF models have been published. In this paper, the model of HIFs in transmission lines is accomplished using the characteristics of a ZnO arrester, which is then implemented within the overall transmission system model based on the electromagnetic transients program (EMTP). This paper proposes an algorithm for fault detection and classification for both LIFs and HIFs using Adaptive Network-based Fuzzy Inference System (ANFIS). The inputs into ANFIS are current signals only based on Root-Mean-Square (RMS) values of 3-phase currents and zero sequence current. The performance of the proposed algorithm is tested on a typical 154 kV Korean transmission line system under various fault conditions. Test results demonstrate that the ANFIS can detect and classify faults including LIFs and HIFs accurately within half a cycle.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.7
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• pp.782-787
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• 2014

Due to the complicated steel structure and safety concern, it is very difficult to deploy wireless networks in power plants. This paper presents a hybrid network, named as $P^2HYMN$ (Power Plant HYbrid Maintenance Network), encompassing PLC (Power Line Communication), TLC (Telephone Line Communication), and Wireless LAN. The design goal of $P^2HYMN$ is to integrate multimedia data such as design drawings of control equipment, process data, and video image data for maintenance operation in electric power plants. A Multiplex Line Communication (MLC) device was designed and implemented to integrate PLC, TLC, and Wireless LAN into $P^2HYMN$. Performance test of $P^2HYMN$ has been conducted on a testbed under various conditions. The throughput of TLC was shown as 39 Mbps. Because the bandwidth requirement per camera is 8.5 Mbps on average, TLC is expected to support more thant four video camera at the same time.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1291-1298
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• 2023

Surveillance reconnaissance sensor network is used for surveillance in wartime and area of operation. In this paper, we propose a target localization method using the detection signal strength of seismic sensors. Relay equipment calculates the target location using coordinate information and detection signal strength of the seismic sensors. Target localization error deviation due to environmental factors was minimized by subtracting the dynamic offset when calculating the target location. Field test shows improvement of target localization through reduction of errors. The average error was decreased to 3.62m. Up to 62% improved result was obtained compared to weighted centroid localization method.

• Journal of Korea Port Economic Association
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• v.25 no.2
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• pp.259-276
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• 2009

The study herein has focused on offering foundation infrastructure in order for seamen who arrive at Korean ports to use internet service smoothly in waiting time and free time. It also concentrated on how to build communication infrastructure for efficient operations when improving existing ports and developing new ports. For this, it has grasped the tendency of researches concerning the existing port communication and has also investigated the status and problems of communication infrastructure being used currently in ports. So it has suggested several realistic development methods based on mesh network and has reviewed them in terms of the stability, economic feasibility and efficiency. Additionally, this research offers the results of the performance test conducted on major equipment in market by the suggested methods. This research can be a good guideline in building wireless communication systems of ports and is expected to contribute to creating traffic volume by improving the image of ports.

• Journal of Information Technology Services
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• v.22 no.5
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• pp.99-108
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• 2023

As the computerization of hospitals becomes more advanced, security issues regarding data generated from various medical devices within hospitals are gradually increasing. For example, because hospital data contains a variety of personal information, attempts to attack it have been continuously made. In order to safely protect data from external attacks, each hospital has formed an internal team to continuously monitor whether the computer network is safely protected. However, there are limits to how humans can monitor attacks that occur on networks within hospitals in real time. Recently, artificial intelligence models have shown excellent performance in detecting outliers. In this paper, an experiment was conducted to verify how well an artificial intelligence model classifies normal and abnormal data in network traffic data generated from medical devices. There are several models used for outlier detection, but among them, Random Forest and Tabnet were used. Tabnet is a deep learning algorithm related to receive and classify structured data. Two algorithms were trained using open traffic network data, and the classification accuracy of the model was measured using test data. As a result, the random forest algorithm showed a classification accuracy of 93%, and Tapnet showed a classification accuracy of 99%. Therefore, it is expected that most outliers that may occur in a hospital network can be detected using an excellent algorithm such as Tabnet.

• Journal of Advanced Navigation Technology
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• v.17 no.4
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• pp.421-428
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• 2013

Voice over IP refers to technology that enables routing of voice conversations over the Internet or a TCP/IP network. VoIP communication costs cheaper than traditional analog phone. Phone calls can be made to anywhere / anyone: Both to VoIP numbers as well as people with normal phone numbers. VoIP protocol equipment available today follows the SIP standard. Older VoIP equipment though would follow H 323, MGCP, Megaco/H.248. A SIP server is the main component of an IP PBX, dealing with the setup of all SIP calls in the TCP/IP network. A SIP server is also referred to a Asterisk IP-PBX. A VoIP telephone, also known as a SIP phone or a softphone, allows the user to make phone calls to any softphone, mobile or PC by using App store. A VoIP telephone can be a simple software-based softphone. However, the SIP Server and the program is vulnerable to VoIP attacks. In this paper, eavesdropping attacks tested by using the Asterisk SIP server. Eavesdropping attacks and TLS security methods apply to VoIP system. TLS can be applied to determine whether the eavesdropping available for VoIP Environments.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.489-497
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• 1999

국내의 ATM 기술은 대부분 교환기 시스템 개발에 집중되어 있었고 최근에는ATM 서비스 분야에 대한 개발 요구가 있다. 이러한 가운데 Internet 서비스는 데이타 망의 기본 서비스로 자리잡았으며, ATM망도 기본적으로 Internet 서비스를 지원하여야 한다. IETF의 IPOA (Classical IP and ARP over ATM)는 국내 망 여건 및 구현의 용이성으로 Internet 서비스를 위한 프로토콜중 가장 선호 대상이지만 RFC사양의 허술함, 구현자의 사양에 대한 이해 부족과 초기 외산 장비 제조 업체들의 자체 사양때문에 기존의 IPOA장비들과 상호 운용 시험에서 후발 IPOA 개발자는 시행착오를 겪어야만 한다. 본 논문에서는 기존 외산 IPOA 장비들과 자체 개발한 장비와 상호 운용 시험을 수행하면서 겪은 사례 연구를 정리하였고 이를 기초로 기존의 외산 IPOA와 상호 운용할 수 있는 최종 요구 사항을 제시하였다. 본 논문을 기초로 IPOA 장비를 개발한다면 국내 후발 ATM 장비 업체는 개발의 시간 및 노력을 줄일 수 있고 향후 IP/ATM 국내 기술력 향상에 도움이 될 것이다.Abstract While we have been focusing on development of ATM switching systems, recently the demand on service by use of ATM switching system is increasing rapidly. Among various ATM services, the Internet service should be provided in an ATM network since the Internet service has been the basic data service. Many domestic engineers consider the classical IP and ARP over ATM (IPOA) to be an appropriate method for interworking of IP and ATM because the IP is the network protocol used in most domestic data networks, and the IPOA is simpler and has less overhead than other approaches. However, it is not easy for a developer to implement the IPOA function module interoperable with other existing ones due to the incomplete description of IETF's RFC specifications, misunderstanding of designer and/or developer, and incompatible vendors' specifications. In this paper, we show several case studies undertaken for interoperability tests of IPOA products between our product and other vendor's products, and discuss the implementation requirement of the IPOA software to be interoperable with the existing IPOA equipment.The design and implementation requirements presented in this paper will reduce the effort of IPOA-developing engineers and time required for interoperability test. Also, this contribution will be helpful in IP/ATM interworking areas.