• The Journal of Engineering Geology
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• v.22 no.2
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• pp.185-194
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• 2012

The efficient maintenance and management of steep slopes often require excessive professional resources and quantitative investigations. Therefore, it is important to develop technology for objective scientific site investigations and quantitative evaluations of steep slopes. This study proposes a 'Mobile System' for steep slopes in order to improve the effectiveness of site investigations compared with conventional methods using anevaluati on table. By analyzing site investigations and desktop studies, the required software and hardware are identified to develop the 'Mobile System', consisting of a 'Field Information Input System' and an 'Analysis System'. The applicability of the system is verified by its application to an area with steep slopes affected by debris flows. The use of this system is expected to increase the efficiency of maintaining steep slope sand to reduce the time and resources required.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.4
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• pp.1-11
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• 2012

This study prepared the list of planning components required for constructing environment-friendly industrial complex and grasped major environment-friendly planning components by measuring the importance per each planning component via the survey for specialists. As a result of measuring the importance of planning component according to each field for constructing environment-friendly industrial complex, it is indicated that important planning components in natural environment field are establishing complex location plan considering its configuration and slope, excluding projects for steep slope-land, establishing countermeasures for reducing contaminants per its source, and separated location of contamination industry around living space. In living environment field, proposed planning components having relatively high importance are separated location of pollution causing industry, establishing energy saving land use plan, linking with green way, circulation network plan, lowering noise level at roadside, plan for separating between pedestrian and vehicle, securing parking space, extending green park and proper location, installing green buffer zone, conserving and forming landscapes, land use for raising energy efficiency, and expansion of energy source. In case of ecological environment, core planning components such as conserving upper class of ecological naturality degree, conserving main habitat, and biotope forming plan are suggested. This study is limited to find out planning components for constructing environment-friendly physical environment of industrial complex which is a part of non-production process. The approach to solve environmental problem by linking spatially production process and non-production process. There is a need to conduct follow-up study to constructing technique for environment-friendly industrial complex considering production & nonproduction process afterward.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.128-134
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• 2013

In the summer season (June~August) during the study period of Lake Doam, average concentrations of major water quality parameters, COD, SS, TN, and TP were 4.0, 16.2, 3.129 and $0.077mg\;L^{-1}$, respectively, and Chl-a was $11.8mg\;m^{-3}$. The result has indicated that Lake Doam was a meso-eutrotrophic lake. Lake Doam data from the summer season (June~August), precipitation from 2001 to 2012, and water quality (COD, SS, TN, TP, Chl-a etc.) of seven years (2001, 2002, 2004 and 2009~2012), were statistically analyzed for long-term trends by Mann-Kendall test and Sen's slope estimator methods. The statistical results showed that precipitation, SD, COD, TN, $NO_3-N$, $NH_3-N$ and Chl-a had decreasing trends, and EC, turbidity, SS, TP and DIP had increasing trends. Suspended solids and total phosphorus were directly affected by precipitation. In the case of suspended solids, more aggressive and constructive plans need to be implemented than the current turbidity reduction project to achieve the targeted water quality ($5mg\;L^{-1}$ of SS) in Lake Doam. In particular, we need to specify a project that considers the steep topographic characteristics of high, land farming areas and precipitation conditions of the Lake Doam watershed, which can increase the efficiency of a turbidity reduction project.

• Geomechanics and Engineering
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• v.34 no.3
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• pp.267-284
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• 2023

Landslides are one of the most dangerous phenomena and natural disasters. Landslides cause many human and financial losses in most parts of the world, especially in mountainous areas. Due to the climatic conditions and topography, people in the northern and western regions of Iran live with the risk of landslides. One of the measures that can effectively reduce the possible risks of landslides and their crisis management is to identify potential areas prone to landslides through multi-criteria modeling approach. This research aims to model landslide potential area in the Oshvand watershed using a support vector machine algorithm. For this purpose, evidence maps of seven effective factors in the occurrence of landslides namely slope, slope direction, height, distance from the fault, the density of waterways, rainfall, and geology, were prepared. The maps were generated and weighted using the continuous fuzzification method and logistic functions, resulting values in zero and one range as weights. The weighted maps were then combined using the support vector machine algorithm. For the training and testing of the machine, 81 slippery ground points and 81 non-sliding points were used. Modeling procedure was done using four linear, polynomial, Gaussian, and sigmoid kernels. The efficiency of each model was compared using the area under the receiver operating characteristic curve; the root means square error, and the correlation coefficient . Finally, the landslide potential model that was obtained using Gaussian's kernel was selected as the best one for susceptibility of landslides in the Oshvand watershed.

• Journal of Environmental Impact Assessment
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• v.17 no.5
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• pp.271-278
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• 2008

The purpose of this research provides the basic solution about waterfront and promotes the inherent capability, that recoveries both the river and gives the river for water quality to improve plan. In this study, we compare and analysis the slope contact between filter media of the porous concrete and planting concrete. As a result, when appling the porous concrete, it can show the removal efficiency is SS 53%, BOD 39%, COD 20%, T-N 36% T-P 42% and appling planting concrete is SS 58%, BOD42%, COD 26%, T-N 45%, T-P 53%. Therefore, planting concrete is higher removal efficiency (SS 5%, BOD 3%, COD 6%, T-N 9%, T-P 10%) than porous concrete. The experimental results show that using purification filter media on planting concrete is better than on porous concrete, because it have the higher purification filter efficiency. The quality of water improves vegetarian concrete, that can expect the increase of the self-purification capacity and improve the spectacle for providing the waterside and planting of planting concrete. In addition, it can complete and apply the research if having enough time for experimentation and accurate study for mechanism by plant, we can use both planting concrete filter media and the existing dike. As a result, we can gain the better quality of the water of the city's rivers and good economic value, that is spread by all cities applicable technologies. So it can be expected using well for future.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.85-89
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• 2011

In this paper, a novel Class-E power amplifier using metamaterials has been realized with one RF LDMOS diffusion metal-oxide-semiconductor field effect transistor. The CRLH structure can lead to metamaterial transmission line with the Class-E power amplifier tuning capability. The CRLH TL is achieved by the frequency offset and the nonlinear phase slope of the CRLH TL for the matching network of the power amplifier. Also, the proposed power amplifier has been realized by using the CRLH structure in the output matching network for better efficiency. Operating frequencies are chosen at 13.56 MHz in this work. The measured results show that the output power of 39.83 dBm and the gain of 11.83dB was obtained. At this point, we have obtained the power-added efficiency (PAE) of 73 % at operation frequency.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.56-61
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• 2010

In this paper, high efficient power amplifier with dual band has been realized. Dual band power amplifier have used modify stub matching for single FET, center frequency 2.14GHz and 5.2GHz respectively. The dual-band operation of the CRLH TL is achieved by the frequency offset and the nonlinear phase slope of the CRLH TL for the matching network of the power amplifier. Because the control of the all harmonic components is very difficult m dual-band, we have managed only the second- and third-harmonics to obtain the high efficiency with the CRLH TL in dual-band. Dual-band characteristics in the output has to balance. Two operating frequencies are chosen at 2.14 GHz and 5.2 GHz in this work. The measured results show that the output power of 28.56 dBm and 29 dBm was obtained at 2.14 GHz and 5.2 GHz, respectively. At this point, we have obtained the power-added efficiency (PAE) of 65.824 % and 69.86 % at two operation frequencies, respectively.

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.36-43
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• 2017

Blade design optimization of QTP-UAV prop-rotor was conducted using ModelCenter(R). Performance efficiency of the blade in hover and forward flight were adopted as the multi-objective function. Required power and pitch link force applied to constraint in each flight mode and limited lower than the value of the baseline blade. Design variables of root chord length of the blade, taper ratio, twist slope, twist angle at 0.5R of the blade, anhedral angle, parabolic coefficient of a tip shape and location of airfoil were used to generate the blade planform. CAMRAD-II, the comprehensive analysis program of rotorcraft, was used for performance analysis of prop-rotor blade in design process. Performance of the optimized blade improved 1.6% of figure of merit in hover and 13.6% of propulsive efficiency in forward flight. Pitch link force also reduced approximately 30% less than that of the baseline blade.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.717-726
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• 2020

The physical characteristics of the major varieties of perilla were analyzed to use as basic data for the design of a high-quality, high-efficiency perilla cleaner and stone separator. Because the size, thousand-grain weight, angle of repose, angle of friction, bulk density and terminal velocity of perilla have significant differences according to the perilla variety, the different of characteristics by variety should be considered for performance improvement of a perilla cleaner and stone separator. Therefore the cleaner and stone separator using a sieve could be improved by the application of a detachable sieve or by using equipment such as a 2 - 3 stage sieve and regulating the slope. Moreover, because differences in the terminal velocity occur due to the differences in the size and thousand-grain weight according to the perilla variety, a blower with an adjustable fan speed was considered for the design of the improved cleaner. Additionally, it was shown that the length of perilla has the greatest correlation based on a comparison of the coefficients of the other characteristics. Accordingly, the length of perilla could be used as a major factor for the fine adjustment and parts replacement of the device. These results can be used as basic data for a high-quality, high-efficiency perilla cleaner and stone separator. In the future, the development of the machine and follow-up studies based on the basic data are needed to determine the optimized operating conditions and mechanism of action.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.59-64
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• 2024

In this study, we conducted research on a miniaturized transmission system suitable for ultra-compact electric vehicles, such as electric arts or small electric cars. While conventional electric vehicles eliminate multi-gear transmissions and control motor output or secure initial driving force through reducers, in vehicles like electric karts or compact electric cars, which have relatively small battery capacities, the driving range can be reduced or the motor can be stressed epending on the loading state. Therefore, in this study, we developed a low stage ratio 0.625 and high stage ratio 1.6 a two-stage transmission system that can change gears as needed, considering factors such as slope conditions and loading status, by applying the continuously variable transmission (CVT) mechanism. Based on the selected gear ratios, we designed the transmission and created a test rig to verify the power transmission efficiency of the developed transmission. Using the test rig, we varied the rotational speed and load of the transmission to confirm its power transmission characteristics and also examined the heat generation characteristics during shifting and operation. As a result, developed a two-stage transmission with a CVT structure.