• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.1-14
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• 2006

This paper presents the techniques developed using the line source method to internally generate waves on an arc in a rectangular grid system. For five different types of wave generation layouts, quantitative experiments were conducted under the following conditions: the propagation of waves on a flat bottom, the refraction and shoaling of waves on a planar slope, and the diffraction of waves to a semi-infinite breakwater. Numerical experiments were conducted using the extended mild-slope equations of Suh et al. (1997). The fifth type of wave generation layout, consisting of two parallel lines connected to a semicircle, showed the best solutions, especially for a small grid size.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.202-207
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• 2015

A CMOS relaxation oscillator, with high robustness over process, voltage and temperature (PVT) variations, is designed in $0.18{\mu}m$ CMOS. The proposed oscillator, consisting of full-differential charge-discharge timing circuit and switched-capacitor based voltage-to-current conversion, could be expanded to a simple open-loop frequency synthesizer (FS) with output frequency digitally tuned. Experimental results show that the proposed oscillator conducts subcarrier generation for frequency-modulated ultra-wideband (FM-UWB) transmitters with triangular amplitude distortion less than 1%, and achieves frequency deviation less than 8% under PVT and phase noise of -112 dBc/Hz at 1 MHz offset frequency. Under oscillation frequency of 10.5 MHz, the presented design has the relative FS error less than 2% for subcarrier generation and the power dissipation of 0.6 mW from a 1.8 V supply.

• Analytical Science and Technology
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• v.22 no.3
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• pp.272-276
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• 2009

This study was performed to investigate the disinfection efficiency and the generation characteristics of disinfection by-products (DBPs) in the sewage effluent. In the case of total coliforms, disinfection efficiency higher than 99%, the required contact time was 30 min at chlorine dose of 0.5 mg/L, 20 min at 1.0 mg/L, and 10 min at 1.5 mg/L, respectively. When the sewage effluent was disinfected with chlorine dose of 0.5 mg/L for 10 min, the maximum generation concentration of trihalomethanes (THMs), haloacetonitriles (HANs) and haloacetic acid (HAAs) were $32.2{\mu}g/L$, $2.97{\mu}g/L$, and $16.29{\mu}g/L$, respectively. The concentration of chloroform was $28.4{\mu}g/L$ corresponding to 88.1% of the THMs. The concentration of HANs and HAAs were found to be inconsiderable. The average residual chlorine concentration of sewage effluent was 0.4 mg/L, the generation concentration of THMs was maximum $1.72{\mu}g/L$ and average $2.79{\mu}g/L$. HANs and HAAs were under the detection limit by GC/MSD.

• Journal of the Korean Solar Energy Society
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• v.36 no.1
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• pp.63-73
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• 2016

How effectively a wind farm captures high market prices can greatly influence a wind farm's viability. This research identifies and creates an understanding of the effects that result in various capture prices (average revenue earned per unit of generation) that can be seen among different wind farms, in the current and future competitive SMP (System Marginal Price) market in South Korea. Through the use of a neural network to simulate changes in SMP caused by increased renewables, based on the Korea Institute of Energy Research's extensive wind resource database for South Korea, the variances in current and future capture prices are modelled and analyzed for both onshore and offshore wind power generation. Simulation results shows a spread in capture price of 5.5% for the year 2035 that depends on both a locations wind characteristics and the generations' correlation with other wind power generation. Wind characteristics include the generations' correlation with SMP price, diurnal profile shape, and capacity factor. The wind revenue cannibalization effect reduces the capture price obtained by wind power generation that is located close to a substantial amount of other wind power generation. In onshore locations wind characteristics can differ significantly/ Hence it is recommended that possible wind development sites have suitable diurnal profiles that effectively capture high SMP prices. Also, as increasing wind power capacity becomes installed in South Korea, it is recommended that wind power generation be located in regions far from the expected wind power generation 'hotspots' in the future. Hence, a suitable site along the east mountain ridges of South Korea is predicted to be extremely effective in attaining high SMP capture prices. Attention to these factors will increase the revenues obtained by wind power generation in a competitive electricity market.

• Journal of Mechanical Science and Technology
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• v.18 no.5
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• pp.753-761
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• 2004

In this paper, an efficient method for generating 5-axis cutting data for a turbine blade is presented. The interference elimination of 5-axis cutting currently is very complicated, and it takes up a lot of time. The proposed method can generate an interference-free tool path, within an allowance range. Generating the cutting data just point to the cutting process and using it to obtain NC data by calculating the feed rate, allows us to maintain the proper feed rate of the 5-axis machine. This paper includes the algorithms for: (1) CL data generation by detecting an interference-free heel angle, (2) finding the optimal tool path interval considering the cusp-height, (3) finding the adaptive feed rate values for each cutter path, and (4) the inverse kinematics depending on the structure of the 5-axis machine, for generating the NC data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.6.1-10
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• 1996

Starting from the Debye theory of rotational Brownian motion equation, we derive an expression for explaining the generation of Maxwell displacement current (MDC) across single monolayers on a material surface. The orientational order parameter and the dielectric relaxation the of monolayers are derived. Based on fille analyses developed here, we examine the MDC across phospholipid monolayers with thermal stimulation due to the change in the spontaneous polarization, and the generation of MDC from 4-cyano-4\`-5-alkayl-biphenyl(5CB) Langmuir-film at the onset of transition by monolayer compression

• Wind and Structures
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• v.9 no.5
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• pp.369-386
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• 2006

A combination Aerodynamic/Atmospheric Boundary Layer (AABL) Wind and Gust Tunnel with a unique active gust generation capability has been developed for wind engineering and industrial aerodynamics applications. This facility is a cornerstone component of the Wind Simulation and Testing (WiST) Laboratory of the Department of Aerospace Engineering at Iowa State University (ISU). The AABL Wind and Gust tunnel is primarily a closed-circuit tunnel that can be also operated in open-return mode. It is designed to accommodate two test sections ($2.44m{\times}1.83m$ and $2.44m{\times}2.21m$) with a maximum wind speed capability of 53 m/s. The gust generator is capable of producing non-stationary gust magnitudes around 27% of the mean flow speed. This paper describes the motivation for developing this gust generator and the work related to its design and testing.

• Journal of Hydrogen and New Energy
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• v.31 no.5
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• pp.436-443
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• 2020

The performance prediction model of a solid oxide fuel cell stack has been developed using deep neural network technique, one of the machine learning methods. The machine learning has been received much interest in various fields, including energy system mo- deling. Using machine learning technique can save time and cost requried in developing an energy system model being compared to the conventional method, that is a combination of a mathematical modeling and an experimental validation. Results reveal that the mean average percent error, root mean square error, and coefficient of determination (R2) range 1.7515, 0.1342, 0.8597, repectively, in maximum. To improve the predictability of the model, the pre-processing is effective and interpolative machine learning and application is more accurate than the extrapolative cases.

• Land and Housing Review
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• v.7 no.3
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• pp.131-136
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• 2016

The aim of this study was to improve the performance of hybrid energy harvesting block merge the vibrations and the pressure developed in the previous study. The power generation performance of the energy block improved in this manner was measured and compared with the energy performance of the products previously developed. In previous models, the center has placed a piezoelectric, the two sides had arranged a vibration applying electromagnetic inducing type. Improved model was disposed three in a row of three unit modules for one block. We change the design in the following way. That is, a unit module has been placed the upper piezoelectric body, the lower portion were arranged three electron donation. In laboratory conditions, the power generation performance evaluation results of the improved energy block is as follows. Once when the vibration, power generation was determined to 1.066W. When compared with previous studies, and power generation performance is improved up to 235%. When the vibration in a row 5, power generation was determined to 1.830W. When compared with previous studies, the performance is improved to 177%. The purpose of developing a hybrid energy block is intended to produce electricity by the pressure and vibration when a vehicle passes through the energy block installed in the car park the mouth portion. Electricity produced will try to take advantage of for the purpose of operating a guiding beacon and LED signage in the parking lot entrance. Therefore, it is determined that there is a need in the experiment to compare the performance of the power generation in the field.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.431-448
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• 2021

We decided the efficient application timings of organo-synthetic insecticides for controlling the first generation larvae of O. furnacalis through investigations of insect stage-specific densities, damage aspects in maize, and effects of insecticides. A waxy maize cultivar, Ilmichal, was cultivated from April 20 (sowing) to July 26 (harvest, dough stage of maize) in Suwon, 2016. The maximum and 50% cumulative catch dates of the overwintering generation adults in the sex pheromone trapping were May 29 and May 31, respectively. Most of the first generation larvae finished their occurrence till the early reproductive stage of maize. The first generation larvae fed on leaves inside the whorl leaves before tassel and stem development of maize, sequentially moved to tassel and stem, and then moved finally to stem and ear parts. In the results of insecticide applications at different dates, the 9-11 leaf stage (June 10~17) and the 6-7 leaf stage (June 3) of maize were the most efficient application timings for direct spray of Etofenprox EC to maize, and for application of Carbofuran granules onto soil surface, respectively, which resulted in suppression of tunnelling damages. The timings for the two insecticides were 12-19 days and 5 days after the adult maximum catch date, respectively. Those timings after the 50% cumulative adult catch date were advanced 2 days.