• Journal of Korea Society of Industrial Information Systems
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• v.23 no.1
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• pp.23-29
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• 2018

A stand-alone Photovoltaic (PV) system is one of the most important energy system for Mongolian nomadic herders. Basically, a stand-alone PV system uses two DC-DC converters. This makes the system costly, size bigger and difficult to move from one place to another place for the nomadic herders. A combined control algorithm for charging the battery using Stage of Charge (SOC) and Maximum Power Point Tracking (MPPT) is proposed in this paper. The batteries are charged by the three stage method; bulk, absorption and float charge. In the bulk stage used the MPPT function in this study. The performance of the proposed control algorithm is evaluated in both steady and changing weather conditions. The results are obtained using PSIM software. The results obtained in this paper are useful in designing a stand-alone PV system in the rural life like Mongolian nomadic herders.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.213-218
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• 2007

Domestic by opening of world construction market with recent FTA should be achieved systematic action that of exoteric surrounding construction environment to inculcate this because consciousness structure unpreparedness of legation fields about quality is expose for hindrance factor for QI in construction spot by quality and organization management official important thing for building company's QI because conquest is possible through QI of construction to possess government official and international competitiveness of customer satisfaction by offering consumer building of change and good quality rapidly, organization's CEO determination must become side improvement the formation government official enemy, and when inspect by each process, responsible persons participate cooperation enterprise space-time. To improve this because complete charge department for quality control appears that organization management need complete charge department being expose by greatly unprepared misgovernment in heavy hydrogen building company, expense that CEO under direct control histiocyte modeling air with AHP analysis is economical will be cost, but is construed can bring excellent effect in operation management side of quality and organization such as cost-cutting effect in maintenance side and I should do so that can occupy competitive power high position with tissue at active quality complete charge deputy.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.569-576
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• 2023

An agricultural drones are gradually increasing in utilization due to economic efficiency, and consist of a main frame in charge of flying spray system in charge of moving pesticide to control targets. Therefore, the environment and characteristics of crops should be considered when controlling pesticides using drones and conditions such as systematic flying altitude of flight, speed, and spray time should be changed accordingly. However, pest control work using agricultural drones has different spray effects depending on level the operation proficiency and spray impact. In addition, there are variations in operating standards and control efficiency for agricultural drones, which hinder the distribution of agricultural control drones in the field of pest control work. Therefore, this study attempts to identify the spraying characteristics of agricultural drones, apply the effective spraying time, interval and experimentally verify the system that can calculation of spray area compared to previous studies. Through this experimental verification, it is intended to apply the optimal control process by minimizing the obstacles to pest control work by applying the operation method and systematic figures to agricultural drones.

• Journal of IKEEE
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• v.16 no.3
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• pp.203-210
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• 2012

Since the non-overlapping gate driver used in conventional DC-DC boost converters generates fixed dead-times, the converters suffer from the body-diode conduction loss or the charge-sharing loss. To reduce the efficiency degradation due to these losses, this paper presents a PWM DC-DC boost converter with adaptive dead-time control. The proposed DC-DC boost converter delivering 3.3V output from a 2.5V input is designed with CMOS $0.3{\mu}m$ technology. It operates at 500kHz and has a maximum power efficiency of 97.3%.

• Tunnel and Underground Space
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• v.20 no.4
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• pp.299-307
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• 2010

The model experiments, which employ a charge hole and guide hole, are simulated to examine the effect of the guide hole on the crack propagation control in blasting. Crack patterns resulted from the analysis models, which consider the distance between the charge hole and guide hole, were compared. From the simulation analysis for the model experiments, it was revealed that all the guide holes used in this study were effective for controlling the crack propagation in blasting.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.3
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• pp.231-237
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• 2016

Recently, the interest in DC systems to achieve more efficient connection with renewable energy sources, energy storage systems, and DC loads has been growing extensively. DC systems are more advantageous than AC systems because of their low conversion losses. However, the DC-link voltage is variable during operation because of different random effects. This study focuses on DC voltage stabilization applied in stand-alone DC microgrids by means of voltage ranges, power management, and coordination scheme. The quality and stability of the entire system are improved by keeping the voltage within acceptable limits. In terms of optimized control, the maximum power should be tracked from renewable resources during different operating modes of the system. The ESS and VSDG cover the power shortage after all available renewable energy is consumed. Keeping the state of charge of the ESS within the allowed bands is the key role of the control system. Load shedding or power generation curtailment should automatically occur if the maximum tolerable voltage variation is exceeded. PSIM-based simulation results are presented to evaluate the performance of the proposed control measures.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.40-48
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• 2015

As advantages of LPG-DI engine, LPG is directly injected into combustion chamber during compression stroke to reduce compression temperature, prevent knock and spontaneous combustion, and adjust engine output using the amount of directly injected fuel, thereby reducing pumping loss caused by throttle valve. Stratified charge can be supplied nearby spark plugs to allow for overall lean combustion, which improves thermal efficiency and can cope with problems regarding emission regulations. In addition, it is characterized by free designing of intake manifold. Despite the fact that LPG-DI has many advantages as described above, there is lack of detailed investigation and study on spray characteristics, combustion flame characteristics, and ignition probability. In this study, a visualization experiment system that consists of visualization combustion chamber, air supply control system, emission control system, LPG fuel supply system, electronic control system and image data acquisition system was designed and manufactured. For supply of stratified charge in the combustion chamber, alignment of injector and spark plugs was made linear.

• Journal of Magnetics
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• v.17 no.1
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• pp.27-32
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• 2012

Transcranial magnetic stimulation requires an electric field composed of dozens of V/m to achieve stimulation. The stimulation system is composed of a stimulation coil to form the electric field by charging and discharging a capacitor in order to save energy, thus requiring high-pressure kV. In particular, it is charged and discharged in capacitor to discharge through stimulation coil within a short period of time (hundreds of seconds) to generate current of numerous kA. A pulse-type magnetic field is formed, and eddy currents within the human body are triggered to achieve stimulation. Numerous pulse forms must be generated to initiate eddy currents for stimulating nerves. This study achieved high internal pressure, a high number of repetitions, and rapid switching of elements, and it implemented numerous control techniques via introduction of the half-bridge parallel load method. In addition it applied a quick, accurate, high-efficiency charge/discharge method for transcranial magnetic stimulation to substitute an inexpensive, readily available, commercial frequency condenser for a previously used, expensive, high-frequency condenser. Furthermore, the pulse repetition rate was altered to control energy density, and grafts compact, one-chip processor with simulation to stably control circuit motion and conduct research on motion and output characteristics.

• Tunnel and Underground Space
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• v.20 no.2
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• pp.125-130
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• 2010

Model blast experiments of mortar blocks were performed to investigate the effect of the guide hole on crack growth. The mortar block specimens have a blast charge hole and 8 guide holes. Two of circular guide hole, notched guide hole, diamond shaped guide hole and diamond shaped guide holder are installed around 110 mm, 165 mm and 220 mm apart from the charge hole for each specimen. From the blast experiments, it was revealed that all the guide hole used in this study were effective for controlling the crack growth at the fracture control.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2636-2640
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• 2003

KARI had developed an Local Area Augmentation System for aircraft precision landing as following ICAO SARPs(Standards and Recommended Practices) draft and FAA's recommended algorithm( carrier smoothing techniques). JPO in charge of managing GPS has introduced the signal structure of GPS modernization program. This paper estimates the accuracy performance of KARI-LAAS with modernized GPS signal but the same processing algorithm.