• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.555-562
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• 2008

In this paper we proposed a practical low-power design technique using clock-gating in RTL. An efficient low-power methodology is that a high-level designer analyzes a generic system and designs a controller for clock-gating. Also the desirable flow is to derive clock-gating in normal synthesis process by synthesis tool than to insert directly gate to clock line. If low-power is considered in coding process, clock is gated in coding process. If not considered, after analyzing entire operation. clock is Bated in periods of holding data. After analyzing operation for clock-gating, a controller was designed for it, and then a low-power circuit was generated by synthesis tool. From result, we identified that the consumed power of register decreased from 922mW to 543mW, that is the decrease rate is 42%. In case of synthesizing the test circuit using synthesizer of Power Theater, it decreased from 322mW to 208mW (36.5% decrease).

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.11
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• pp.621-628
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• 2016

Recently, remote controls for home appliances have been produced as many as the number of home appliances per household, and new home appliances are being released, but the number of new remote controls is continuously increasing due to their separate functions. Therefore, it is not inconvenient for first time users to use many remote controls because it is difficult and bulky. In recent years, the practical use of a universal remote control, such as large companies such as SAMSUNG and LG are producing a variety of forms. In this paper, we explain how to transmit and receive data format and infrared remote control through custom code identification method used in IR remote control for each company, and to see the size, characteristics and difference with ordinary remote control through ATmega128 remote control experiment. The ATmega128 can be used to control various home appliances displayed on the LCD. As a result, it can be seen that the number of remote controllers having only each function is reduced, and the integrated remote controller using ATmega128 Can handle household appliances.

• Journal of Practical Engineering Education
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• v.8 no.2
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• pp.111-120
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• 2016

Education equipment for field programmable gate array (FPGA) design of sensor-based IOT (Internet Of Thing) system is introduced. Because sensors have different interfaces, several types of interface controller on FPGA need. Using this equipment, several types of interface controller, which can control ADC (analog-to-digital converter) for analog sensor outputs and $I^2C$ (Inter-Integrated Circuit), SPI (Serial Peripheral Interface Bus), and GPIO (General-Purpose Input/Output) for digital sensor outputs, can be designed on FPGA. Image processing hardware using image sensors and display controller for real and image-processed images or videos can be design on FPGA chip. This equipment can design a SOC (System On Chip) consisting of a hard process core on Linux OS and a FPGA block for IOT system which can communicate with wire and wireless networks. Using the education equipment, an example of hardware design using image sensor and accelerometer is described, and an example of syllabus for "Digital system design using FPGA" course is introduced. Using the education equipment, students can develop the ability to design some hardware, and to train the ability for the creative capstone design through conceptual, partial-level, and detail designs.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.14-21
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• 2011

Reliability means that a product maintains its initial quality and performance at certain period of time(time, distance, cycle etc) under given condition without failure. Given conditions include both environmental condition and operating condition. Environmental condition means common natural environment such as temperature, humidity, vibration, and working condition means artificial environment such as voltage, current load, install place, hours of use, which occurs during using the product. In the field of railway vehicles, although components of railway vehicles with reliability are the trend of mandatory as persisting period of railway vehicles is extended, using components of railway vehicles is insufficient for the practical reliability assessment. but the meaning of the first railway operating agnecy to acquire the parts in the field, the data suggest the reliability of products if you can and can show the reliability of modular units and modular units can provide the reliability of if you can present reliability of the entire system is thought to be here. In this study, lifespan of micro-switch for master controller is analyzed and prediction is performed based on its field data considering the special circumstances of railway vehicles operating agency, such as a large number of trains operates on the same line.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.194-198
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• 2012

This paper describes flying inspection apparatus for 22.9kV distribution line. This apparatus is composed of multi-copter(more than 4 propellers), camcorder and remote controller. The existing inspections, such as hot-line inspection job and optical inspection method and distribution Line Checking Robot, have many restrictions. A electric working vehicle and hot-line job license are essential in hot-line inspection job. Besides its high cost, it can't be applied to the electric pole over 18m and road-blocked area. Optical method can't inspect upper side of electric facilities mounted on the electric pole. Robot method can't be applied to the corroded overhead earth wire and nothing of overhead earth wire. To solve the problems, in Korea Electric Power Co., we have applied flying inspection apparatus to the 22.9kV distribution line. The results of trial application show that this paper is practical and effective for the inspection technical method in 22.9kV distribution line

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.1
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• pp.1162-1170
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• 2001

This paper proposes a practical gain-scheduling control law considering robust stability and performance of Linear Parameter Varying(LPV) systems in the presence of nonlinearities and uncertainties. The proposed method introduces LMI-based pole placement synthesis and also associates with a recently developed fuzzy control system based on Takagei-Sugenos fuzzy model. The sufficient conditions for robust controller design of linearized local dynamics and robust stabilization of fuzzy control systems are reduced to a finite set of Linear Matrix inequalities(LMIs) and solved by using co-evolutionary algorithms. The proposed method is applied to the longitudinal acceleration control of high performance aircraft with linear and nonlinear simulations.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.71-72
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• 2011

This paper presents a novel and direct dead time compensation method of the 3 phase inverter using space vector pulse width modulation(SVPWM) topology. In the turn on time calculation of the effective voltage, the dead time effect is directly compensated according to the current direction of the midium voltage reference. Since the turn on time of the effective voltage vector is affected by the dead time, the loss time is compensated to turn on time of the effective voltage vector. And the dead time is added to the calculated voltage vector switching times according to the current direction. For the more effective compensation, the direction of the midium phase current is considered by the practical direction and voltage drops in the power devices. The proposed method can compensate the dead time which is considered feedback error or direction of middle phase current without coordinate transform in added controller. The proposed dead time compensation scheme is verified by the computer simulation and experiments of 3 phase R L load.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.164-174
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• 1996

This paper presents control and response characteristics of a continuously variable ER(electrorheological) damper for small-sized vehicles. The ER damper is devised and its governing equation of motion is derived from the bond graph model. The field-dependent yield shear stresses are distilled from experimental investigation on the Bingham property of the ER fluid. The distilled data are incorporated into the governing system model and, on the basis of this model, an appropriate size of the ER damper is manufactured. After evaluating the field-dependent damping performance of the proposed ER damper, the skyhook control algorithm is formulated to achieve desired level of the damping force. The controller is then experimentally implemented and control characteristics of the ER damper are presented in order to demonstrate superior controllability of the damping force. In addition, response characteristics of the damping force with respect to the electric field with fast on-off frequency are provided to show the feasibility of practical application.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.315-322
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• 2009

Penetration and installation of a new dynamic technology known as Flexible AC Transmission Systems (FACTS) in a practical and dynamic network requires and force expert engineer to develop robust and flexible strategy for planning and control. Unified Power Flow Controller (UPFC) is one of the recent and effective FACTS devices designed for multi control operation to enhance the power system security. This paper presents a dynamic strategy based on Particle Swarm Optimization (PSO) for optimal parameters setting of UPFC to enhance the system loadability. Firstly, we perform a multi power flow analysis with load incrementation to construct a global database to determine the initial efficient bounds associated to active power and reactive power target vector. Secondly a PSO technique applied to search the new parameters setting of the UPFC within the initial new active power and reactive power target bounds. The proposed approach is implemented with Matlab program and verified with IEEE 30-Bus test network. The results show that the proposed approach can converge to the near optimum solution with accuracy, and confirm that flexible multi-control of this device coordinated with efficient location enhance the system security of power system by eliminating the overloaded lines and the bus voltage violation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4529-4548
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• 2016

DDoS attacks have had a devastating effect on the Internet, which can cause millions of dollars of damage within hours or even minutes. In this paper we propose a practical dynamic defense approach that overcomes the shortage of static defense mechanisms. Our approach employs a group of SDN-based proxy switches to relay data flow between users and servers. By substituting backup proxy switches for attacked ones and reassigning suspect users onto the new proxy switches, innocent users are isolated and saved from malicious attackers through a sequence of remapping process. In order to improve the speed of attacker segregation, we have designed and implemented an efficient greedy algorithm which has been demonstrated to have little influence on legitimate traffic. Simulations, which were then performed with the open source controller Ryu, show that our approach is effective in alleviating DDoS attacks and quarantining the attackers by numerable remapping process. The simulations also demonstrate that our dynamic defense imposes little effect on legitimate users, and the overhead introduced by remapping procedure is acceptable.