• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.693-696
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• 2005

KIGAM (Korea Institute of Geoscience and Mineral Resources) launched a new project to develop the low-temperature geothermal water in the area showing high geothermal anomaly, north of Pohang city, for large-scale space heating. Surface geologic and geophysical surveys including Landsat 1M image analysis, gravity, magnetic, Magnetotelluric (MT) and controlled-source audio-frequency MT (CSAMT), and self-potential (SP) methods have been conducted and the possible fracture zone was found that would serve as deeply connected geothermal water conduit. In 2004, two test wells of 1.1km and 1.5km depths have been drilled and various kinds of borehole survey including geophysical logging, pumping test, SP monitoring, core logging and sample analysis have followed. Temperature of geothermal water at the bottom of 1.5km borehole reached over $70^{\circ}C$ and the pumping test showed that the reservoir contained huge amount of geothermal water. Drilling for the production well of 2 km depth is on going. After test utilization and the feasibility study, geothermal water developed from the production well is going to be provided to nearby apartments.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.215-219
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• 2005

A macro spreadsheet model, WEANES (Wet Pond Annual Efficiency Simulation Model), has been developed to predict the long-term or annual removal efficiencies of wet retention/detention basins. The model uses historical, site-specific, multi-year, rainfall data, usually available from a nearby National Oceanic and Atmospheric Administration (NOAA) climatological station to estimate basin efficiencies which are calculated based on annual mass loads. Other required input parameters are: 1) watershed parameters; drainage area, pervious curve number, directly connected impervious area, and ti me of concentration, 2) pond parameters; control and overflow elevations, pond side slopes, surface areas at control elevation and pond bottom; 3) outlet structure parameters; 4) pollutant event mean concentrations; and 5) pond loss rate which is defined as the net loss due to evaporation, infiltration and water reuse. The model offers default options for parameters such as pollutant event mean concentrations and pond loss rate. The model can serve as a design, planning, and permitting tool for consulting engineers, planners and government regulators.

• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.761-768
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• 1997

A numerical model is developed to analyze the incompressible unsteady flow induced by the pump trip-out in the cooling water discharge culvert of thermal power plants. The numerical models has various features to deal concureently with the overall behavior of complicated unsteady flow due to the presence of cooling water internal system, seal well, air chamber, culvert, manholes, open channel and sea water. A leap-frog finite difference scheme is employed to solve governing equations, and the model is tested for a simple case of two tanks connected with a pipe. A fixed free surface boundary condition used earlier at the downstream end of culvert for large water body is investigated.

• Archives of Reconstructive Microsurgery
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• v.5 no.1
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• pp.16-23
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• 1996

The omental pedicle based on right gastroepiploic vessels is designed new experimental model for prefabrication(revasculirization) of skin flaps in rats. A $2.5{\times}4cm$ pack of omentum with right gastroepiploic vessels was transferred under a bipediceld panniculocutaneous flap which is $2.5{\times}8cm$ size. At day 7, all four margin was divided and the flap was rasied as an secondary island flap connected only by its vascular pedicle, then the composite flap sutured back in place. The flap perfusion was examined by dermofluorometry and flap survival area was measured at day 12. The Secondary island flap demonstrated a dye fluorescence index(DFI%) of $31.38{\pm}12.33$ and survival rate $80.47{\pm}9.61$ The survival rate was increased when DFI% and contact surface between vascular carrier and skin flap was increased. An india ink injection and histologic examination provided visual evidence of revasculization. The omental pedicle is a promising and safe model for revasculirization of other tissues.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.10
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• pp.1481-1487
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• 2017

This paper proposes a sensorless speed control algorithm for parallel-connected dual Surface-mounted Permanent Magnet Synchronous Motors fed by a single inverter. For stable parallel operation of synchronous motors with a single inverter, each motor has to be constantly kept in the synchronization state regardless of load torque. If the master motor with the larger load is controlled, the synchronous state will be maintained. Therefore, detection of the master motor is essential. Conventionally, the master motor is determined by comparing the rotor position error from the relation between the back-EMF for torque angle and the flux position. consequently, the position sensor is deemed essential for finding the rotor position. In this paper, we proposed a method that decides the magnitude of the load from the power angle of two motors due to the load variation and selects the motor to control through the sign function for the sensorless speed control without the position sensor. The results of simulation and experiment conducted verify the efficacy of the proposed method.

• Journal of the Korean Society of Safety
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• v.21 no.3 s.75
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• pp.1-7
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• 2006

Nowadays, out of other transmission parts, the sleeve is getting more and more important part for exact and smooth shifting from gear ratio change whenever drivers are needed. To exact and smooth shifting when drivers are needed, all the parts connected with gear shifting should be machined exactly and having dimensions designers are intended. Especially, in case of the sleeve that the most important functional part to shift from gear ratio change that drivers are intended, it needs high precision grade and quality in both sides runout and outer dia runout as well as inner spline small dia & large dia. Because it's assembled with the synchro hub spline and shifted directly with the mating cone. So, it should be applied the hear treatment(hereinafter referred to H.T.M.T) to prevent the friction and percussion loss from shifting with mating cone. At this time, the deformation problems are raised from almost H.T.M.T. process and it makes the inferior part.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.153-159
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• 2004

This study was focused on evaluating physical properties and SO$_{x}$ removal capability of porous lime filters prepared by a foaming and a gelcasting method. Porosities of lime filters ranged from 55% to 85%, and their mean pore sizes were about 95 ${\mu}{\textrm}{m}$. It was observed that porous lime filters had the continuous pore structure that most pores were inter-connected by many windows. Before SO$_{x}$ removal reaction a surface of porous lime filters was made up of calcium oxide, but after reaction calcium sulfate became a main component. The SO$_{x}$ removal efficiency and the conversion ratio of calcium oxide to calcium sulfate increased according to reaction temperature and porosity. At 100$0^{\circ}C$, SO$_{x}$ removal efficiency of filters was always over 98% regardless of the porosity. In case of the filter with the porosity of 85%, the conversion ratios of calcium oxide increased according to the reaction temperature, and they were in the range 30% to 60%. to 60%.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.15-21
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• 2014

The aim of this work is conduct the study on light weight and structural performance improvement of the composite wind power blade. GFRP (Glass Fiber Reinforced Plastic) pre-empted by CFRP(Carbon Fiber Reinforced Plastic), the major material of wind power blade, was identified the superiority of mechanical performance through the tensile and fatigue test. SENT(Single Edge Notched Tension) specimen fracture test was conducted on the specimen that laminated together 2 ply CFRP with 4 ply GFRP through DIC(Digital Image Correlation) analysis. The SENT specimen thickness and $a_0/W$ ratio is 1.45 mm and 0.2, respectively. The fracture test accomplished with displacement control with 0.1 mm/min at the room temperature. The experimental apparatus used for the fracture test consisted of a 50kN universal dynamic tester and CCD camera connected to a personal computer (PC), which was used to record images of the specimen surface. Following data acquisition, the images and load-displacements were transferred to the PC, on which the DIC software was implement. The experiment and DIC analysis results show that CFRP/GFRP laminated composite exhibits improvement of the strength, compared with that of the existing blade material. This study shows the result that the strength of CFRP rotor blade of wind turbine satisfies through the experimental and DIC method.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.62-69
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• 2020

This paper proposes a pattern recognition and classification algorithm based on a circular structure that can reflect the characteristics of the sEMG (surface electromyogram) signal measured in the arm without putting the placement limitation of electrodes. In order to recognize the same pattern at all times despite the electrode locations, the data acquisition of the circular structure is proposed so that all sEMG channels can be connected to one another. For the performance verification of the sEMG pattern recognition and classification using the developed algorithm, several experiments are conducted. First, although there are no differences in the sEMG signals themselves, the similar patterns are much better identified in the case of the circular structure algorithm than that of conventional linear ones. Second, a comparative analysis is shown with the supervised learning schemes such as MLP, CNN, and LSTM. In the results, the classification recognition accuracy of the circular structure is above 98% in all postures. It is much higher than the results obtained when the linear structure is used. The recognition difference between the circular and linear structures was the biggest with about 4% when the MLP network was used.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.1
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• pp.4-14
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• 2005

CarboKorea and HydroKorea are the domestic projects aiming to improve our understanding of carbon and water cycles in a typical Korean forest located in a complex terrain with a watershed connected to large rivers. The ultimate goal is to provide a nowcasting of these cycles for the whole Peninsula. The basic strategy to achieve such goal is through the inter- and multi-disciplinary studies that synthesize the in-situ field observation, modeling and remote sensing technology. The challenge is the fact that natural ecosystems are nonlinear and heterogeneous with a wide range of spatio-temporal scales causing the variations of mass and energy exchanges from a leaf to landscape scales. Our paradigm now shifts from temporal variation at a point to spatial patterns and from spatial homogeneity to complexity of water and carbon at multiple scales. Yet, a large portion of our knowledge about land-atmosphere interactions has been established based on tower observations, indicating that the development of scaling logics holds the key to the success of CarboKorea and HydroKorea. Here, we review the pioneering work of FIFE (First ISLSCP Field Experiment) on scaling issues in a temperate grassland and discuss the lessons from it for the application to Gwangneung forest site.