• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.129-129
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• 2000

This paper describes the concept and method of Controlling an illuminator using Power-Line Modem. Nowadays it is being studied and developed the Power-Line communication. The communication using Power-Line can realize Building-Automation and Home-Automation easily and chiefly. Because it has no need constructing an additional equipment. In this study it is used The Power-Line Modem, illuminators and microcontrollers which enable RS-232C serial communication.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.212-218
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• 1999

In this study , Computer programs for the optimum and automation desgin of reinforced concrete box culvert were developed. It was shown that even though the strarting points and optimization method are different the objective function and optimum design variables converge to a value within a close range respectively, and consequently the optimum design program developed in the study is reliable and stron. 3D-design drawing can be drawn using automation desgin computer program developed in this study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.211-213
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• 1998

This paper introduces the additional remote monitoring and remote setting functions needed to operate the distribution automation system effectively. we compare the additional functions with the old functions. The remote setting of minimum trip value of fault indicator is an example of additional function. It saves time and line-man's power. Also this paper describes the data transmission flow diagram for operation of distribution automation system using wireless communication method.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1626-1634
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• 2015

LCL filters are widely used in three-phase PWM converter for its advantages of small volume, low cost and inhibition of high frequency current harmonic. However, it is difficult to optimize its design because its parameters are mutually influenced while the value of each parameter for LCL filter has impacts on the converter's cost and size. In this paper, the target of optimization is to minimize the parameter values of LCL filter, and an optimization method for parameters of LCL filter of three-phase PWM converter based on least square method is proposed. With this method, a quantitative calculation of the harmonic component of the converter’s side phase voltage is performed first, and then the quantitative relationship between phase voltage harmonics and grid phase current harmonics is analyzed. After that, the attenuation requirement of each harmonic is obtained by taking into account the requirements for each harmonic component of grid current. Then according to the optimization objective, the objective function with minimum harmonic attenuation deviation is established, and least squares method is adopted for three-dimensional global searching of parameters for LCL filter. Thus, the designed harmonic attenuation curve approximates the minimum attenuation requirements, and the optimized LCL filter parameters are obtained. Finally, the effectiveness of the method is verified by the experiments.

• 한국컴퓨터정보학회논문지
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• 제3권3호
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• pp.139-150
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• 1998

과학과 정보통신의 발달로 그리고 컴퓨터의 폭넓은 보급으로 지금까지 인력에 의해 이루어지던 제반 서류전달 및 서류결재가 컴퓨터에 의해 자동으로 처리하거나 수행할 수있도록 하는 공장자동화(Factory Automaton : FA), 그리고 사무자동화(Office Automation : OA)로 발전하였으며 이러한 기술을 무역업무에 적용시키는 무역의 사무자동화(Trade Automation : TA)에 무역업계와 무역관련기관이 관심을 가지고 있다. 본 논문은 한국의 무역자동화에 관한 현황을 고찰함으로서 EDI의 효용성과 가치, 필요성을 강조하고자 한다.

• 정보보호학회논문지
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• 제33권5호
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• pp.787-799
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• 2023

가정에서 IoT 장비가 많이 활용되면서, IoT 장비를 통합하여 사용자의 편의에 맞게 사용하는 IoT automation system을 향한 관심도 많아졌다. IoT automation system에서는 사전 정의된 자동화규칙에 따라 IoT 장비의 정보를 수집하고, IoT 장비가 작동한다. 하지만 공격자는 패킷을 지연시켜 실제 상태와 시스템에서 인식한 상태의 불일치가 되는 시간을 만든다. 이 시간 동안 시스템은 사전 정의한 자동화 규칙대로 동작하지 않는다. 제안된 지연공격 탐지방법이 일부 있지만, 트래픽량이나 배터리에 민감한 IoT system에 적용하기에 제한사항이 있다. 본 논문에서는 IoT 시스템에 적용할 수 있는 실용적인 패킷 지연 공격 탐지 방법을 제시한다. 제안 방법은 메시지를 전송할 때, 메세지의 전송을 알리는 패킷을 브로드캐스트로 발송함으로써 서버가 이벤트의 발생을 인지할 수 있도록 한다. 평가를 위하여 Raberry pi로 구현된 IoT system을 구성하고, 패킷 지연 공격에 대하여 평균2.2초이내로탐지할 수 있음을 보였다. 실험 결과 소모 전류 Overhead는 초당 평균 2.5 mA, 트래픽 Overhead는 15% 발생하였고, 기존 제안된 탐지방법보다 효율적으로 Delay attack을 탐지할 수 있음을 밝혔다.

• Journal of Power Electronics
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• 제16권4호
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• pp.1324-1335
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• 2016

This article explores the speed regulation problem of permanent magnet synchronous motor (PMSM) systems subjected to unknown time-varying disturbances. A continuous sliding mode control (CSMC) technique is introduced for the speed loop to enhance the robustness of PMSM systems and eliminate the chattering phenomenon caused by high-frequency switch function in the conventional control law. However, the high control gain of the CSMC law in the presence of strong disturbances leads to large steady-state speed fluctuations for PMSM systems. In many application fields, PMSM systems are affected by time-varying disturbances instead of constant disturbances. For example, electric bicycles are usually affected by changing environmental disturbances, including wind speeds, road conditions, etc. These disturbances may be in the form of constant, ramp, and parabolic disturbances. Hence, a generalized proportional integral (GPI) observer is employed to estimate these types of disturbances. Then, the disturbance estimation method and the aforementioned CSMC method are combined to establish a composite sliding mode control method called the CSMC+GPI method for the speed loop of PMSM systems. Contrary to the conventional sliding mode control technique, the proposed method completely eliminates the chattering phenomenon caused by the switching function in the conventional control law. Moreover, a small control gain for the CSMC+GPI method is chosen by feed-forwarding estimated values to the speed controller. Hence, the steady-state speed fluctuations are small. The effectiveness of the proposed control scheme is verified by simulation and experimental result.

• Journal of Power Electronics
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• 제15권6호
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• pp.1567-1576
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• 2015

Offline inductance identification of a permanent magnet synchronous motor (PMSM) is essential for the design of the closed-loop controller and position observer in sensorless vector controlled drives. On the base of the offline inductance identification method combining direct current (DC) offset and high frequency (HF) voltage injection which is fulfilled at standstill, this paper investigates the inverter nonlinearity effects on the inductance identification while considering harmonics in the induced HF current. The negative effects on d-q axis inductance identifications using HF signal injection are analyzed after self-learning of the inverter nonlinearity characteristics. Then, both the voltage error and the harmonic current can be described. In addition, different cases of voltage error distribution with different injection conditions are classified. The effects of inverter nonlinearities on the offline inductance identification using HF injection are validated on a 2.2 kW interior PMSM drive.

• 한국통신학회논문지
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• 제16권10호
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• pp.992-1000
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• 1991

현대는 생산성 향상을 위하여 이런 방법이 사용되는데 그중 공장 측면에서는 공장 자동화를 함으로서 생산성 향상을 기하는 방법을 사용하고 있다. 공장 자동화의 첫 단계는 각 단위 공장의 자동화이다. 우리나라 현황을 보면 소수의 발전된 공장의 경우 라인의 자동화가 구축되어 있으며 대다수의 기업은 단위 공정의 자동화 장치가 설치되고 있다. 그러나 현재 설치된 장비로서 더 이상의 생산성을 높이기 위해서는 각 단위 공정간의 협력 또는 공조체계 및 사무자동화와의 인계가 이루어져야 한다. 이에 본 논문에서 제시된 공정 감시 제어 SYSTEM은 각 공정의 자동화를 이루고 각 단위 공장의 자동화를 이루고 각 단위 공정을 MAIN COMPUTER와 연결하여 모든 공정을 MASTER SYSTEM화하여 통계처리 및 감시 기능을 하고자 하여 생산성을 향상시키고자 한다.

• Journal of Power Electronics
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• 제16권1호
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• pp.287-296
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• 2016

Conventional maximum power point tracking (MPPT) methods are ineffective under partially shaded conditions because multiple local maximum can be exhibited on power-voltage characteristic curve. This study proposes an improved cuckoo search (ICS) MPPT method after investigating the cuckoo search (CS) algorithm applied in solving multiple MPPT. The algorithm eliminates the random step in the original CS algorithm, and the conception of low-power, high-power, normal and marked zones are introduced. The adaptive step adjustment is also realized according to the different stages of the nest position. This algorithm adopts the large step in low-power and marked zones to reduce search time, and a small step in high-power zone is used to improve search accuracy. Finally, simulation and experiment results indicate that the promoted ICS algorithm can immediately and accurately track the global maximum under partially shaded conditions, and the array output efficiency can be improved.