• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.1
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• pp.33-38
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• 2006

This paper proposes a simple MPPT control scheme of a based Current-Control-Loop system that can be obtains a lot of advantage to compare with another digital control method, P&O(Perturbation and Observation) and IncCond(Incremental Conductance) algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. Therefore, it is applied a small home power generation system that required many expenses. But, a proposed method is easy to solve the cost reduction and power unbalance Problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment results on battery charger using PIC that is the microprocessor of a low price.

• Biomedical Science Letters
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• v.26 no.4
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• pp.275-287
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• 2020

Since its introduction in the forensic field, quantitative PCR (qPCR) has played an essential role in DNA analysis. Quality of DNA should be evaluated before short tandem repeat (STR) profiling to obtain reliable results and reduce unnecessary costs. To this end, various human DNA quantification kits have been developed. Among these kits, the PowerQunat® System was designed not only to determine the total amount of human DNA and human male DNA from a forensic evidence item, but also to offer data about degradation of DNA samples. However, a crucial limitation of the PowerQunat® System is its high cost. Therefore, to minimize the cost of DNA quantification, we evaluated kit performance using a reduced volume of reagents (1/2-volume) using DNA samples of varying types and concentrations. Our results demonstrated that the low-volume method has almost comparable performance to the manufacturer's method for human DNA quantification, human male DNA quantification, and DNA degradation index. Furthermore, using a reduced volume of regents, it is possible to run 2 times more reactions per kit. We expect the proposed low-volume method to cut costs in half for laboratories dealing with large numbers of DNA samples.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.440-447
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• 2002

This paper considerated about exact flow volume calculation method from factors having an influence on measurement and introduced in anesthesia ventilator realized spirometry system. System used differential pressure sensing method with factors, that is temperature, pressure, gas density, humidity and mucus etc. System optimized for low power system for mobile system. System composed analog interface part, signal processing part, display part. Analog interface part have differential pressure flow sensor and defferential pressure sensor. Signal processing part have AVR processor for low power system display part use serial port (RS232, SPT). so it display at pc monitor or send to anesthesia ventilator. System is stable by linearizing 2th characteristics of flow-differential pressure, auto correction of sensor. Noise reduced by algorithm with analog filter and digital processing. Small, light, low power system is good at mobile system and applied to patient in emergency or mobile. and, System is useful at anesthesia ventilator by using flow sensor.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.10
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• pp.2006-2013
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• 2015

In this paper we propose a multi-protocol gateway system based on low power wireless communications. The proposed multi-protocol gateway system was designed to allow real-time monitoring and control of the on-site situation through wired and wireless networks by gathering information for streetlight power control and environmental monitoring. The sensing data using multi-sensors with composite processing that selectively used wired or wireless communication (e.g., CDMA, Ethernet (TCP/IP), GPS, etc.) were designed to act as intermediaries that transmitted to the main server through ZigBee. Inaddition, they were designed by separating a CPU board and baseboard to ensure low maintenance cost and ease of hardware replacement. The proposed multi-protocol gateway system's power, impact, continuous operation stability, and immunity test results obtained a normal operation success rate of over 95% and normal continuous operation results. Moreover, in the voltage drop test, instantaneous immunity test, and conductive RF electromagnetic field immunity test, it obtained an average rating result of "A".

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.361-365
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• 2005

Since the fuel cell uses the hydrogen for its fuel. it has no emission and higher efficiency than an internal combustion engine. Also fuel cell is much quieter than engine generator and generates heat much less than engine generator. So it has advantage of Army's 'si lent watch' capability and the ability to operate undetected by the enemy. The fuel cell hybrid system combines a fuel cell power system with an ESS. The ESS (e.g., batteries or ultracapacitors) reduces the fuel cell's peak power and transient response requirements. It allows the fuel cell to operate more efficiently and recovery of vehicle energy during deceleration. The battery has high energy density, so it has the advantage regarding driving distance. However, it has a disadvantage considering dynamic characteristic because of low power density. One other hand. the ultracapacitor has higher power density, so it can handle sudden change or discharge of required power. Yet. it has lower energy density. so it will be bigger and heavier than the battery when it has the same energy. This paper proposes the power management strategy for multi-power source fuel cell hybrid system. which is applied with the merits of both battery and ultra capacitor by using both of them simultaneous.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1219-1226
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• 2014

This paper introduces a hardware simulator for the LVRT operation analysis of the grid-tied PMSG wind power system with a power dissipation circuit. The power dissipation circuit, which is composed of chopper and resistor, suppresses the sudden increase of DC-link voltage in the back-to-back converter of the grid-tied PMSG wind power system. The LVRT operation was first analyzed using computer simulations with PSCAD/EMTDC. A wind power simulator including the power dissipation circuit and the fault simulator composed of variac and IGBT were built to analyze the LVRT operation. Various experiments were conducted to verify the effectiveness of the power dissipation circuit for the LVRT operation. The developed hardware simulator can be extensively utilized for the analysis of various LVRT operations of the grid-tied wind power system.

• Journal of Power System Engineering
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• v.13 no.4
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• pp.56-61
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• 2009

In recent years, since the continuing increase in the capacity in personal computer such as the optimal performance, high quality and high resolution image, the computer system's components produce large amounts of heat during operation. This study analyzes and investigates the ability and efficiency of a cooling system inside a computer by means of central processing unit (CPU) and power supply cooling fan. This research was conducted to enhancement of efficiency of the cooling system inside the computer by making a structure which produces different air pressures in an air inflow tube. Consequently, when temperatures of the CPU and room inside computer were compared with a general personal computer, temperatures of the tested CPU, the room and the heat sink were as low as $5^{\circ}C$, $2.5^{\circ}C$ and $7^{\circ}C$ respectively. In addition to, revolution per minute (RPM) was shown as low as 250 after 1 hour operation. This research explored the possibility of enhancing the effective cooling of high-performance computer systems.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2147-2150
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• 2003

Recently, many technologies of the P.L.C (Power Line Carrier) are introduced for an efficient communication. P.L.C communication sends information in the carrier signals by conduction over the power wire. An arc detector is proposed in this paper for the effective transmission. The Power Line Carrier has an advantage in low cost because it uses existent power line. It can be easily applied anywhere that a power line socket is available. But the P.L.C. is very noisy, because many electronic devices in generate electronic noise in modulated signals. This problem should be considered carefully in the design of the arc detector system using P.L.C in railway. The proposed system can be applied for monitoring the arc detector system and the arc locator system in railway. Hence the system will be able to exchange the arc information to be T.C.M.S. (Train Control Management System), bogies and even between a station and trains in railway and use to suspicion fire in train.

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.503-510
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• 2010

This paper proposes the use of fuzzy applications to a 4-machine and 10-bus system to check stability in open conditions. Fuzzy controllers and the excitation of a synchronous generator are added. Power system stabilizers (PSSs) are added to the excitation system to enhance damping during low frequency oscillations. A fuzzy logic power system stabilizer (PSS) for stability enhancement of a multi-machine power system is also presented. To attain stability enhancement, speed deviation ($\Delta\omega$) and acceleration ($\Delta\varpi$) of the Kota Thermal synchronous generator rotor are taken as inputs to the fuzzy logic controller. These variables have significant effects on the damping of generator shaft mechanical oscillations. The stabilizing signals are computed using fuzzy membership functions that are dependent on these variables. The performance of the fuzzy logic PSS is compared with the open power system, after which the simulations are tested under different operating conditions and changes in reference voltage. The simulation results are quite encouraging and satisfactory. Similarly, the system is tested for the different defuzzification methods, and based on the results, the centroid method elicits the best possible system response.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.3
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• pp.95-103
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• 2007

Portable multimedia Player (PMP) devices have been gaining in its popularity with the emerging digital convergence of data, video, audio, etc. Since the PMP devices are typically equipped with DSP, a bigger LCD screen, and a hard disk, efficient power management has become more crucial than the other portable devices. This paper builds up a hardware/software-based power measurement system based on data acquisition devices. Subsequently, it measures and analyzes the power consumed in commercial PMP devices under different types of events: the system boot & shutdown, video playback, and the use of different video-coding types. Finally, our analysis of the measured power consumption patterns reveals useful information for the design of low-power PMP devices.