• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.695-700
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• 2009

Maintaining an IAQ with fresh in school building is very important because the good IAQ can be possible to improve the academic performance. Since school buildings are very dense and require a lot of fresh air, the need for ERV(Energy Recovery Ventilator) has become obvious. While opening a window does provide ventilation, the building's heat and humidity will then be lost in the winter and gained in the summer, both of which are undesirable for the indoor climate and for energy efficiency. ERV technology offers an optimal solution: fresh air, better climate control and energy efficiency. However, when the outdoor air condition is favorable to control the indoor environment such as spring and autum in Korea, heat exchange in ERV would rather increase the cooling load than diminish. Economizer cycle control which using the outdoor air in controlling the indoor thermal environment has many benefit in terms of energy saving and IAQ control. In this study, the ERV with economizer cycle control will be suggested. And then the system control characteristics and energy saving effect will be analyzed through the TRSNSYS Simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1273-1277
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• 2011

This paper proposes a control-based approach for duty cycle adaptation in wireless sensor networks. The proposed method, QCon, controls duty cycle through queue management in order to achieve high performance under variable traffic rates. To minimize energy consumption while meeting delay requirement, we design a feedback controller, which adapts the sleeping time according to dynamically changing traffic by constraining the queue length at a predetermined value. Based on control theory, we analyze the adaptive behavior of QCon and derive conditions for system stability. Results from asymptotic analysis and simulations indicate that QCon outperforms existing scheduling protocol by achieving more energy savings while satisfying delay requirement.

• Journal of Power Electronics
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• v.15 no.2
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• pp.443-454
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• 2015

This study proposes a novel one-cycle control scheme with a plug-in repetitive controller for load compensator. The novelty of this scheme lies in the combination of high dynamics and the simplicity of a one-cycle controller and good steady-state harmonic suppression ability of the repetitive controller. In addition, the proposed scheme can reduce the effect of the harmonics in phase voltage for the existence of the repetitive controller. Finally, experimental results on a three-phase, four-wire, three-level load compensator are reported to validate the effectiveness of the proposed control scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.330-337
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• 1998

A duty cycle average model is mathematically developed for an average model of buck converter employing hysteresis c control. The derived model is able to simultaneously deal with both the continuous conduction mode (CCM) and the d discontinuous conduction mode (DCM) in the time domain. Also. taking advantage of the MAST language of SABER. a t template of the proposed duty cycle average model is built for the time and frequency domain analyses. The accuracy of t this template is verified through the computer simulations.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.210-215
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• 2004

: A DNA analysis system based on fluorescence analysis has to have a DNA amplifying thermal cycle system. DNA amplification is executed by the temperature control. Accuracy of fluorescence analysis is influenced by the temperature control technology. For that reason, the temperature control is core technology in developing the DNA analysis system. Therefore, the objective of this paper is to develop the hardware to apply thermoelectric module to the DNA amplifying thermal cycle system. In order to verify the developed hardware for controlling the temperature of thermoelectric module, a DNA amplifying thermal cycle test was performed. From the test, the developed hardware controlled the temperature of thermoelectric module successfully. Therefore, it is expected that the developed hardware can be applied to the DNA amplifying thermal cycle system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.154-161
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• 2010

In wireless sensor networks, due to the many-to-one convergence of upstream traffic, congestion more probably appears. The existing congestion control protocols avoid congestion by controlling incoming traffic, but the duty-cycle operation of MAC(Medium Access Control) layer has not considered. In this paper, we propose DCA(Duty-cycle Based Congestion Avoidance), an energy efficient congestion control scheme using duty-cycle adjustment for wireless sensor networks. The DCA scheme uses both a resource control approach by increasing the packet reception rate of the receiving node and a traffic control approach by decreasing the packet transmission rate of the sending node for the congestion avoidance. Our results show that the DCA operates energy efficiently and achieves reliability by its congestion control scheme in duty-cycled wireless sensor networks.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.145-147
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• 2005

This paper presents a methodology for satisfying the thermal comfort of Indoor environment and reducing the summer peak demand power by minimizing the power consumption for an Air-conditioner within a space. KEPCO(Korea Electric Power Corporation) use the fixed duty cycle control method regardless of the indoor thermal environment. This method has disadvantages that energy saying depends on the set-point value of the Air-Conditioner and DLC has no net effects on Air-conditioners if the appliance has a lower operating cycle than the fixed duty cycle. A variable duty cycle estimates the PMV(Predict Mean Vote) at the next step with a predicted temperature and humidity coming from the back propagation neural network model. It is possible to reduce the energy consumption by maintaining the Air-conditioner's OFF state when the PMV lies in the thermal comfort range. The proposed methodology uses the historical real data of Sep. 7th, 2001 from a classroom in seoul to verify the effectiveness of the variable duty cycle method comparing with fixed duty cycle. The result shows that the variable duty cycle reduces the peak demand to 2.6times more than fixed duty cycle and increases the load control ratio by 8% more. Based on the variable duty cycle control algorithm, the effectiveness of DLC is much more improved as compared with the fixed duty cycle.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2169-2170
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• 2011

This paper presents about the analysis on cost factor reduction using the life cycle cost model for motor block in the KTX-1. Until now, most life cycle cost of the system as a whole that has been studied. but in case of railway industry part, LCC studies are needed on the subsystem like a propulsion control system because subsystems are developed continuously localization. Therefore, In this paper presents cost breakdown structure for life cycle cost (LCC) estimation for localization development of propulsion control system (Motor Block) in high speed railway vehicle (KTX-1). Also to analysis LCC on motor block, it was analyzed physical breakdown structure (PBS) and preventive cost on propulsion control system in view of maintenance cost. Based on this, we describe life cycle cost on motor block of KTX-1.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.145-157
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• 2012

The novel limit cycle analysis of the attitude control system using jet thrusters was presented based on a phase plane method by paper. It was shown in the software simulation results that the analysed results of the limit cycle was more accurate than those of the Haloulakos' method. But it was not verified in the real system. The proposed method is verified in the reaction control system for KSLV-I via an real time hardware in the loop simulation. It can be shown in this test that analyzed result of the limit cycle is very accurate.

• Journal of The Korean Association of Information Education
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• v.11 no.4
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• pp.483-495
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• 2007

In this paper, to establish a way controlling educational contents, range of contents for quality control are offered. And a life-cycle suitable for present circumstance has defined and successive quality control process has suggested supporting development and use of the contents through analyzing the life cycle of its software and previous contents. A life cycle is defined as whole process from formation of contents to its extinction. The developing process includes stages of planning, designing, manufacturing, and the applying process includes evaluation, circulation and management. Suitable quality control guidelines for each process have established and offered. Aim of this paper is also to develop a model which is applicable to developers as well as supporters who help the developing process.