• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.410-411
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• 2011

본 논문에서는 태양광 전원, 배터리, 마이크로터빈, 스마트 홈 등 다양한 목적과 특성을 가진 요소로 구성된 마이크로그리드를 효율적으로 제어, 관리하기 위한 분산 지능형 제어원리를 제안한다. 기존의 중앙집중식 제어원리는 중앙에서 전체 시스템에 대한 정보를 취득하여 운영에 대한 의사결정을 독점하는 구조였다면 제안하는 원리는 마이크로그리드의 구성요소가 각각 지능형 에이전트를 기반으로 스스로 데이터를 취득하고 이웃 에이전트와의 대화와 협조를 통해 분산제어를 수행하는 방식이다. 각 에이전트 사이는 근거리 무선통신 방식인 Zigbee를 이용하였고 마이크로그리드를 실시간으로 해석하기 위하여 MATLAB 기반의 실시간 시뮬레이터를 이용하였다. 실시간 마이크로그리드 시뮬레이션 모델과 에이전트 역할을 하는 마이크로 컨트롤러를 연계하여 Hardware-in-the-loop 기반의 데모시스템을 구축하였고 제안하는 원리에 대해 검증하였다.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.247-248
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• 2007

컴퓨터의 발전은 철도 산업에 큰 영향을 끼치고 있다. 특히 기계식이나 수동식 신호 장치들이 마이크로프로세서를 탑재하면서 전자식, 자동식으로 변경되면서 철도 신호 시스템에 큰 변화를 가져왔다. 이로 인해 안전성은 더 높아지고 수송력 또한 증가하게 되었다. 이런 변화에 핵심적인 역할을 하는 것이 바로 열차집중제어장치이다 열차집중제어장치는 기본적인 역할은 운행되는 열차들의 운전정보를 획득하고 이 정보들을 이용하여 효율적으로 차량을 운행하게 제어하는 것이다. 하지만, 다양한 철도 차량들이 생겨나고 신호 시스템이 발전하게 되면서 열차집중제어장치도 더 다양한 기능과 처리 능력을 가지도록 설계되어져야 한다. 특히, 현재 큰 관심을 받고 있는 무인운전, 무선을 이용한 철도 시스템에서는 열차집중제어장치의 역할이 매우 중요한 부분이 되고 있다. 본 논문에서는 이런 상황을 고려하여 실시간으로 정보를 처리하고, 차량을 안전하게 제어하며, 모든 상황들을 정보화할 수 있는 열차집중제어장치에 대한 설계를 하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.7
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• pp.33-40
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• 2010

The hand over between different radio access networks, especially where their coverage overlaps, suffers various complications since the different access networks provide different service characteristics. In this paper, it is about the system which can control the wireless LAN network management system and the wireless LAN access point of variety vendor which is in different areas. Successful development of mobile sink wireless LAN network management system which supports multi-vendor devices and have center-local interoperability structure. In proposed system, speed of the mobile station give about 10% improvement when the map domain size is 5 than the existing system. Through a data plane and management system of message way, it give a stability system and consistency network.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.3
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• pp.323-328
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• 2009

In this paper, a decentralized fuzzy output feedback controller for the nonlinear networked control system is proposed for wireless sensor network. Especially, it is assumed that the networked control system has the output packet loss and the input transmission failure. For the fuzzy control of the nonlinear subsystem, it presents Takagi-Sugeno (T-S) fuzzy model of each subsystem and it designs the decentralized fuzzy output feedback controller. The stability condition of the closed-loop system with the proposed controller is obtained by Lyapunov functional. The obtained stability condition is represented to the linear matrix inequality (LMI) form, and the control gain is obtained by LMI. An example is given to show the verification discussed throughout the paper.

• Journal of Biosystems Engineering
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• v.20 no.3
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• pp.226-235
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• 1995

An unmanned speed sprayer was developed using a remote control and an inductive cable guidance systems to protect operators and environment from hazardous pesticides. The sprayer consists of a remote control system, an induction system, obstacle detectors, control actuators and an one-chip microcomputer. The sprayer can be operated by the induction guidance and/or remote control. The following summarize characteristics of the developed speed sprayer. 1) Both the remote control and the induction guidance operation were possible with the developed speed sprayer. 2) Sixteen functions of the forwarding, backing, halting, steering, 3-way valve for nozzles and fan operating etc. were utilized on the remote control system. 3) It was concluded that the DTMF method, having less transmitting error, performed better than the FSK method for an agricultural remote controller. A radio station may be necessary. 4) The digital inductive guidance system, consisting of five low-impedance detection coils and a window comparator circuit, performed better than the analog detecting system, guiding route using inductive voltage differential from tow detection coils.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.81-90
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• 2003

Existing web-based system management software solutions show some limitations in time and space. Moreover, they possess such as shortcomings unreliable error message announcements and difficulties with real-time assistance suppers and emergency measures. In order to solve these deficiencies, Wireless Remote Control System was designed and implemented. Wireless Remote Control System is able to manage and monitor remote systems by using mobile communication devices for instantaneous control. The implementation of Wireless Remote Control System leads to these security Problems as well as solutions to aforementioned issues with existing web-based system management software solutions. Therefore, this paper has focused on the security matters related to Wireless Remote Control System. The designed security functions include mobile device user authentication and target system access control. For security verification of these security functions introduced CPN(Coloured Petri Nets) which is capable of expressing every possible state for each stage. And then in this paper was verified its security through PI(Place Invariant) based on CPN(Coloured Petri Nets). The CPN expression and analysis method of the proposed security function can also be a useful method for analyzing other services in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.405-408
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• 2014

오늘날 사람들은 편리함을 추구함으로써 대부분의 현관문에는 전자식 도어락이 설치되고 있다. 여기에는 전자키 시스템, 기계식 조합키등 다양한 방식으로 개인을 인증한다. 이러한 방식들은 사용자가 직접 도어락을 제어해야 한다는 불편한 점이 있고 오래 사용하다 보면 자주 사용한 버튼이 고장이 나거나 사용 흔적이 남아 보안에 취약하다는 문제점이 있다. 본 논문에서는 기존의 도어락 시스템에 불편함과 문제점을 해결하기 위해 안드로이드 기반의 스마트폰과 아두이노 모듈을 활용하여 NFC 및 개인 스마트폰 인증 방식으로 원격 도어락 시스템을 구현한다.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.3
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• pp.156-161
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• 2012

Random access protocol takes advantage of constructing a decentralized wireless network due to its intrinsic spectrum sensing capability. Such technical feature goes well with cognitive radio networks consisting of heterogeneous wireless systems, in which a centralized control between heterogeneous wireless systems is hard to be implemented. Motivated by the decentralized feature of the random access, we adopt the random access protocol in cognitive radio networks, and evaluate the performance of a CSMA-based cognitive radio network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.572-580
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• 2013

IEEE 802.15.4e is a prospective standard for low latency control application in industries. This paper proposes a framework to evaluate the closed loop IEEE 802.15.4e based WNCS performance. The framework consists of two models: closed loop control system model and network model. The network model focuses on the PHY parameters of wireless link and takes the channel parameters into consideration. The PHY model combining with MAC model gives the control system model the probability of packet loss in a super-frame. In addition, redundancy mechanism is considered in IEEE 802.15.4e to reduce to data frame loss probability. The simulation is implemented in Matlab, PHY model takes the channel parameters from empirical results. Hence our evaluation gives insight into behavior of WNCS in different environments and it provides us a tool to design wireless network to achieve a good performance for control system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.2
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• pp.1-8
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• 2012

We propose a new frame length control scheme for cognitive radio systems. In the proposed algorithm, the property that the probability of a primary packet arrival continually increases as time elapses during the primary user's idle period is utilized. When reducing the secondary frame length in accordance with the increasing primary packet arrival probability, spectrum sensing is conducted more frequently as time elapses and the primary packet arrival is detected more quickly. We obtain the optimal frame lengths by maximizing the secondary throughput while satisfying the interference constraint. Numerical results show a significant throughput enhancement via the frame length control.