• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1076-1080
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• 2015

An inventory control system was developed for a distribution system consisting of a single multiproduct warehouse serving a set of customers and purchasing products from multiple vendors. Purchase orders requesting multiple products are delivered to the warehouse in a process. The receipt of customer orders by the warehouse proceeded in order intervals and in order quantities that are subject to random fluctuations. The objective of warehouse operation is to minimize the total cost while maintaining inventory levels within the warehouse capacity by adjusting the purchase order intervals and quantities. An adaptive model predictive control algorithm was developed using a periodic square wave model to represent the material flows. The adaptive concept incorporated a stabilized minimum variance control-type input calculation coupled with input/output stream parameter predictions. The effectiveness of the scheme was demonstrated using simulations.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.5
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• pp.35-41
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• 1998

This paper presents a decoupling controller of the missile seeker scan loop with a spin-stabilized platform. A precise seeker motion with respect to the scan command is essential for the higher acquisition probability of the target. As the seeker scan loop is a deeply cross-coupled two input two output system, an accurate pointing or scanning for each axis to the target is very difficult, even though provided with the help of a high performance controller. When a decoupling control is applied to the seeker scan loop, the cross-coupling between two axes can be reduced to a remarkable amount. As a low order of controller is required for the real time operation, a PI controller with decoupling filter is suggested and compared with other controllers. A linearized dynamic model of seeker scan loop is used and validated through the comparison of experimental results of step responses.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.3
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• pp.34-42
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• 1993

An analytic approach to wide-band amplification using simplified equivalent MESFET modeling has enabled an ultrabroad-band flat-gain amplifier from DC to microwave. The developed lossy-match ultrabroad-band amplifier operates as a RC coupled circuit in the low-frequency range and lossless impedance matching circuit in the microwave frequency range with gain compensation circuits. The reduced gain caused by external resistors is compensated using 2-stage cascade amplification, and the gain of designed unit is 12.5.+-.1dB from the vicinity of DC to 7GAz. The experimental gain characteristics are good agreement with computer simulated results. The input and output VSWRs are measured under 2:1 over the operating frequency range, and the gain goes down over 15dBrange with various gate bias voltages.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.220-224
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• 2012

We report an experimental demonstration of $4{\times}4$ multiple-input multiple-output (MIMO) wireless visible light communications (VLC) using a charge-coupled device image sensor receiver instead of a photodiode receiver. An image sensor is a kind of digital camera, which is used in most mobile devices such as smart phones or laptop computers and a promising commercial candidate for a VLC receiver. The transmission distance of the experimental result is over 10 m, enough for most indoor communication applications. We expect that the MIMO VLC technique based on image sensor receivers can be widely used with the development of high-speed image sensors.

• Proceedings of the KIEE Conference
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• summer
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• pp.893-895
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• 2004

This paper deals with an automatic design standard computation based on a rated watt for a synchronous reluctance motor(SynRM). The focus of this paper is the design relative to the output power on the basis of rotor shape of a SynRM in each rated watt. The copuled Finite Elements Analysis(FEA) & Preisach model have been used to evaluate nonlinear solutions. The proposed procedure allows to define the rotor gemetric dimensions according to the rotor dia and rated watt starting from an existing motor or a preliminary design.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.126-128
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• 2007

This paper presents a new soft switching dc-to-dc converter that employs IM transformer. Detailed analysis and design considerations of the proposed circuits are presented. By applying the proposed magnetic integration procedure, new integrated magnetic circuits featuring low loss, simple structure are then developed to overcome the limitations of prior art. Consequently, the power loss and the size of the integrated magnetic device are greatly reduced. The operation and performance of the proposed converter are demonstrated with an experimental converter that delivers a 5V/5A output from a 48V input at the maximum efficiency of 90 %.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.5
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• pp.485-491
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• 2013

A new passive lossless snubber for boost converter based on magnetic coupling is proposed. It is composed of a winding coupled with boost inductor, one snubber inductor, two snubber capacitor and three additional diodes. Especially, the snubber inductor can not only limit the reverse recovery current of output diode but also minimize switch turn-on losses greatly. Moreover, all of the energy stored in the snubber is transferred to the load in the manner of resonance. To confirm the validity of proposed system, theoretical analysis, design consideration, and verification of experimental results are presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.70-75
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• 2015

High Step-up DC-DC Converters have been demanded for renewable energy applications. Transformer or coupled inductor is generally used to boost output voltage of converters. This methods can relatively obtain high voltage than others, whereas have heavy weight and high cost. To complement these disadvantages, we studied transformerless high step-up DC-DC converter. In various transformerless topologies, Boost converters combined with Cockcroft-Walton have studied. In this paper, we proposed a symmetrical Cockcroft-Walton circuit for transformerless high step-up DC-DC converter. Finally, we simulated proposed converter to compare with existing converter. As a result, proposed converter has higher duty ratio or lower cost than existing transformerless converters which are discussed in this paper.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1425-1427
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• 2005

In this paper, with loosely coupled transformer series-parallel resonant type DC/DC converter is analyzed. To get more efficient operating mode of the series-parallel resonant type DC/DC converter, theoretical analysis using normalized parameters are accepted. The proposed converter must be operated in Pulse Frequency Modulation(PFM) switching pattern for the Zero Voltage Switching(ZVS) operation. According to PFM control method, the output voltage of the proposed circuit can be controlled.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.617-624
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• 2008

This paper proposes design and implementation of wind turbine simulators which incorporate the turbine dynamic characteristics. At first, the turbine output characteristic in steady state is modelled as a function of wind speed and then dynamic characteristics are modelled such as pitch angle control, torsional vibration, tower shadow effect, wind shear effect, and inertia effect. In addition, a wind speed simulator is developed which can generate the real wind speed pattern. The wind turbine simulator is implemented with 3[kW] M-G set(cage-type induction motor coupled with doubly-fed induction generator) at laboratory.