• 전자공학회논문지
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• 제51권5호
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• pp.20-28
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• 2014

본 논문에서는 분산 제어망에서 통신 오류가 발생한 노드를 실시간으로 탐지할 수 있는 기법을 제안한다. 기존의 분산 제어망은 노드 내 오류가 발생하는 지점을 탐지하기 위해, 노드 간 의존성의 영향을 고려해야 하며 이는 전체적인 분산 제어망의 성능 저하의 원인이 될 수 있다. 이를 해결하기 위하여, 본 논문에서 제안된 기법은 각 노드의 손상으로 인해 발생되는 고장노드들을 빠른 시간 내에 탐지하기 위해 단일 Bose-Chaudhuri-Hocquenghem (BCH) 비트를 Cyclic Redundancy Check (CRC) 코드에 삽입하여 기존의 CRC 코드 내 비트와 대체하는 방식을 택한다. 고장 노드 판정의 탐지 정확성을 높이기 위해 고장 가중치 계수를 통한 고장 판단 기법을 제안한다. 제안된 기법의 효용성을 증명하기 위해 MATLAB을 이용하여 모의실험 환경을 구축하고, 제안된 기법의 성능을 분석하였다. 이를 통하여, BCH 코드 내 비트 간 분배를 통해 수정되는 정도에 관계없이 CRC 코드의 성능이 우수하게 보존됨을 알 수 있었으며, 기존의 CRC 코드 기법보다 빠른 시간 내에 손상된 노드를 탐지할 수 있음을 보였다.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1643-1653
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• 2014

This paper presents the design and implementation of a wind-solar hybrid power system for LED street lighting and an isolated power system. The proposed system consists of photovoltaic modules, a wind generator, a storage system (battery), LED lighting, and the controller, which can manage the power and system operation. This controller has the functions of maximum power point tracking (MPPT) for the wind and solar power, effective charging/discharging for the storage system, LED dimming control for saving energy, and remote data logging for monitoring the performance and maintenance. The proposed system was analyzed in regard to the operation status of the hybrid input power and the battery voltage using a PSIM simulation. In addition, the characteristics of the proposed system's output were analyzed through experimental verification. A prototype was also developed which uses 300[W] of wind power, 200[W] of solar power, 60[W] LED lighting, and a 24[V]/80[Ah] battery. The control system principles and design scheme of the hardware and software are presented.

• 제어로봇시스템학회논문지
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• 제21권5호
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• pp.442-446
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• 2015

As electricity consumption is increasing rapidly these days, an urgent. need exists to minimize consumption through smart and intelligent ways in order to prevent a future energy crisis. For this purpose, development of an intelligent peak power management system should be required. As the number of appliances and consumer electrical devices increase, power consumption in unit business tends to grow. Generally, electricity consumption can be minimized using a peak power management system capable of. effectively controlling the load power by continuously monitoring the power. In this work, a peak power management system which consists of arduino microprocessor equipped with ethernet and Zigbee shield is presented. To verify the feasibility of the proposed scheme, laboratory-scale experiments are carried out.

• 한국정보처리학회논문지
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• 제1권4호
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• pp.490-501
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• 1994

본 연구에서는 ATM 네트워크 트래픽 제어에서 사용되는 셀 마킹 기법의 문제점을 제시하고 사용자 레벨의 우선순위를 고려한 확장된 셀 마킹 기법을 제안하였다. 기존 의 트래픽 모니터링 기법에서는 셀의 트래픽 규약 위반 사항만을 가지고 셀의 CLP 비트를 1로 마킹하였다. 이렇게 함으로써 낮은 순위의 셀이 늘어나고, 사용자 레벨의 우선 순위와는 상관없이 셀의 등급이 낮아지게 되었다. 본 연구에서는 FCI 비트와 CLP 비트를 결합하여 3 레벨의 우선 순위 방식을 제안한다. CLP=0인 셀의 레벨을 2 단 계로 구분하였다. 결과적으로 제안한 기법이 기존의 방법보다 높은 순위 셀을 더 많이 보존할 수 있었으며 높은 순위의 셀 손실도 줄일 수 있었다. 또한 제안한 3 레벨에 대 해 두개의 임계차를 갖는 부분 버퍼 공유 기법(PBS : partial buffer sharing)으로 성 능을 분석하였다. 분석 결과 두개의 임계치를 갖는 PBS가 우선 순위없는 기법이나 한 개의 임계치를 가진 PBS 보다 더 효율적인 제어가 가능하였다.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1472-1481
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• 2001

In this paper, an advanced shift controller that supervises the shift transients with adaptive compensation is presented. Modern shift control systems for vehicle automatic transmission are designe d to provide smooth transients for passengers' comfort and better component durability. In the conventional methods, lots of testing and calibration works have been done to tune gains of the controller, but it does not assure optimum shift quality at all times owing to system variations often caused by uncertainties in shifting hydraulic systems and external disturbances. In the proposed control scheme, an adaptive compensation controller with intelligent supervisor is implemented to achieve improved shift quality over the system variations. The control input pattern which generates clutch pressure commands in hydraulic actuating systems, is updated through a learning process to adjust for each subsequent shift based on continuous monitoring of shifting performance and environmental changes. The proposed algorithm is implemented and evaluated on the experimental test setup. Results from the experimental studies for several operation modes show both improved performance and adaptability of the proposed shift controller to uncertain changes of the shifting environment in vehicle power transmission systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권12호
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• pp.4385-4399
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• 2021

The Internet of Things (IoT) eHealth systems composed by Wireless Body Area Network (WBAN) has emerged recently. Sensor nodes are placed around or in the human body to collect physiological data. WBAN has many different applications, for instance health monitoring. Since the limitation of the size of the battery, besides speed, reliability, and accuracy; design of WBAN protocols should consider the energy efficiency and time delay. To solve these problems, this paper adopt the end-edge-cloud orchestrated network architecture and propose a transmission based on reinforcement algorithm. The priority of sensing data is classified according to certain application. System utility function is modeled according to the channel factors, the energy utility, and successful transmission conditions. The optimization problem is mapped to Q-learning model. Following this online power control protocol, the energy level of both the senor to coordinator, and coordinator to edge server can be modified according to the current channel condition. The network performance is evaluated by simulation. The results show that the proposed power control protocol has higher system energy efficiency, delivery ratio, and throughput.

• International Journal of Control, Automation, and Systems
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• 제4권2호
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• pp.204-216
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• 2006

Latest advances in hardware technology and state of the art of mobile robot and artificial intelligence research can be employed to develop autonomous and distributed monitoring systems. And mobile service robot requires the perception of its present position to coexist with humans and support humans effectively in populated environments. To realize these abilities, robot needs to keep track of relevant changes in the environment. This paper proposes a localization of mobile robot using the images by distributed intelligent networked devices (DINDs) in intelligent space (ISpace) is used in order to achieve these goals. This scheme combines data from the observed position using dead-reckoning sensors and the estimated position using images of moving object, such as those of a walking human, used to determine the moving location of a mobile robot. The moving object is assumed to be a point-object and projected onto an image plane to form a geometrical constraint equation that provides position data of the object based on the kinematics of the intelligent space. Using the a priori known path of a moving object and a perspective camera model, the geometric constraint equations that represent the relation between image frame coordinates of a moving object and the estimated position of the robot are derived. The proposed method utilizes the error between the observed and estimated image coordinates to localize the mobile robot, and the Kalman filtering scheme is used to estimate the location of moving robot. The proposed approach is applied for a mobile robot in ISpace to show the reduction of uncertainty in the determining of the location of the mobile robot. Its performance is verified by computer simulation and experiment.

• 대한전기학회논문지:전력기술부문A
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• 제48권10호
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• pp.1293-1302
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• 1999

In this paper, an on-line process scheme is presented for implementation of a intelligent on-line modeling of nonlinear complex system. The proposed on-line process scheme is composed of FNN-based model algorithm and PLC-based simulator, Here, an adaptive fuzzy-neural networks and HCM(Hard C-Means) clustering method are used as an intelligent identification algorithm for on-line modeling. The adaptive fuzzy-neural networks consists of two distinct modifiable sturctures such as the premise and the consequence part. The parameters of two structures are adapted by a combined hybrid learning algorithm of gradient decent method and least square method. Also we design an interface S/W between PLC(Proguammable Logic Controller) and main PC computer, and construct a monitoring and control simulator for real process system. Accordingly the on-line identification algorithm and interface S/W are used to obtain the on-line FNN model structure and to accomplish the on-line modeling. And using some I/O data gathered partly in the field(plant), computer simulation is carried out to evaluate the performance of FNN model structure generated by the on-line identification algorithm. This simulation results show that the proposed technique can produce the optimal fuzzy model with higher accuracy and feasibility than other works achieved previously.

• 한국사이버테러정보전학회:학술대회논문집
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• 한국사이버테러정보전학회 2004년도 제1회 춘계학술발표대회
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• pp.275-282
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• 2004

디지털 저작물의 전송환경이 빠른 속도로 바뀜에 따라서 디지털 저작물의 저작권 보호가 중요한 이슈로 부각되고 있다. DRM(Digital Right Management)은 디지털 저작자나 출판업자, 그리고 인터넷 서비스 제공자들에게 디지털 저작물을 접근하고 사용하는데 있어서 신뢰할수 있는 환경을 만들수 있는 관심있는 분야이다. 본 논문에서는 라이선스 에이전트를 이용하여 기존의 DRM 기법이 가지고 있는 정적인 DRM이나 온라인환경에 제한된 어플리케이션의 단점을 개선한 디지털 저작물의 보호기법에 대하여 제안한다. 제안된 논문은 동적인 DRM기법으로 동적인 요구 제어 기술을 바탕으로 라이선스 에이전트를 이용하여 온라인과 오프라인 환경에서 동시에 모니터링과 추적을 수행한다. 제안된 시스템은 PKI 보안 환경에서 사용자의 행동이나 데이터 보안을 실시간으로 감시하여 불법적인 접근과 사용을 막는다.

• Journal of Communications and Networks
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• 제18권5호
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• pp.846-856
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• 2016

Wireless sensor networks (WSNs) are widely applied in monitoring and control of environment parameters. It is sometimes necessary to disseminate data through wireless links after they are deployed in order to adjust configuration parameters of sensors or distribute management commands and queries to sensors. Several approaches have been proposed recently for data dissemination in WSNs. However, none of these approaches achieves both high efficiency and low complexity simultaneously. To address this problem, cluster-tree based network architecture, which divides a WSN into hierarchies and clusters is proposed. Upon this architecture, data is delivered from base station to all sensors in clusters hierarchy by hierarchy. In each cluster, father broadcasts data to all his children with instantly decodable network coding (IDNC), and a novel scheme targeting to maximize total transmission gain (MTTG) is proposed. This scheme employs a new packet scheduling algorithm to select IDNC packets, which uses weight status feedback matrix (WSFM) directly. Analysis and simulation results indicate that the transmission efficiency approximate to the best existing approach maximum weight clique, but with much lower computational overhead. Hence, the energy efficiency achieves both in data transmission and processing.