• Journal of Wetlands Research
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• v.22 no.4
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• pp.312-320
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• 2020

Various LIDs with natural water circulation function are applied to reduce urban environmental problems and environmental impact of development projects. However, excessive Infiltration and evaporation of LID facilities dry the LID internal soil, thus reducing plant and microbial activity and reducing environmental re duction ability. The purpose of this study was to develop a real-time measurement system with complex sensors to derive the management plan of LID facilities. The test of measurable sensors and Internet of Things (IoT) application was conducted in artificial wetlands shaped in acrylic boxes. The applied sensors were intended to be built at a low cost considering the distributed LID and were based on Arduino and Raspberry Pi, which are relatively inexpensive and commercialized. In addition, the goal was to develop complex sensor measurements to analyze the current state o f LID facilities and the effects of maintenance and abnormal weather conditions. Sensors are required to measure wind direction, wind speed, rainfall, carbon dioxide, Micro-dust, temperature and humidity, acidity, and location information in real time. Data collection devices, storage server programs, and operation programs for PC and mobile devices were developed to collect, transmit and check the results of measured data from applied sensors. The measurements obtained through each sensor are passed through the Wifi module to the management server and stored on the database server in real time. Analysis of the four-month measurement result values conducted in this study confirmed the stability and applicability of ICT technology application to LID facilities. Real-time measured values are found to be able to utilize big data to evaluate the functions of LID facilities and derive maintenance measures.

• Atmosphere
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• v.24 no.2
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• pp.173-188
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• 2014

The KMA has cooperated with the Oklahoma University in USA to develop a Polarimetric Radar Data (PRD) simulator to improve the microphysical processes in Korea Local Analysis and Prediction System (KLAPS), which is critical for the utilization of PRD into Numerical Weather Prediction (NWP) field. The simulator is like a tool to convert NWP data into PRD, so it enables us to compare NWP data with PRD directly. The simulator can simulate polarimetric radar variables such as reflectivity (Z), differential reflectivity ($Z_{DR}$), specific differential phase ($K_{DP}$), and cross-correlation coefficient (${\rho}_{hv}$) with input of the Drop Size Distribution (DSD) and scattering calculation of the hydrometeors. However, the simulator is being developed based on the foreign observation data, therefore the PRD simulator development reflecting rainfall characteristics of Korea is needed. This study analyzed a potential application of the 2-Dimension Video Disdrometer (2DVD) data by calculating the raindrop axis ratio according to the rain-types to reflect Korea's rainfall characteristics into scattering module in the simulator. The 2DVD instrument measures the precipitation DSD including the fall velocity and the shape of individual raindrops. We calculated raindrop axis ratio for stratiform, convective and mixed rainfall cases after checking the accuracy of 2DVD data, which usually represent the scattering characteristics of precipitation. The raindrop axis ratio obtained from 2DVD data are compared with those from foreign database in the simulator. The calculated the dual-polarimetric radar variables from the simulator using the obtained raindrop axis ratio are also compared with in situ dual-polarimetric observation data at Bislsan (BSL). 2DVD observation data show high accuracies in the range of 0.7~4.8% compared with in situ rain gauge data which represents 2DVD data are sufficient for the use to simulator. There are small differences of axis ratio in the diameter below 1~2 mm and above 4~5 mm, which are more obvious for bigger raindrops especially for a strong convective rainfall case. These differences of raindrop axis ratio between domestic and foreign rainfall data base suggest that the potential use of disdrometer observation can develop of a PRD simulated suitable to the Korea precipitation system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.104-111
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• 2016

The steel frame modular housing of which the research and development has been actively carried out recently cannot be constructed through monolithic placement like the reinforced concrete deck of general structure due to the characteristics of construction method of production in the factory and assembly on the site. And floor vertical vibration and deflection caused by inhabitants' activities may become an important issue in the aspect of usability evaluation due to a decrease in the section size of member, a decrease in weight, and so on. Therefore, this study evaluated the vibration performance of deck by using formula of AISC Design Guide 11(hereinafter AISC formula) which was practically used in general for modules where a stud was and wasn't installed at the center of beam in the longitudinal direction in the modular housing to be studied, and examined the applicability of AISC formula through comparison with the results of analysis using a general-purpose analysis program. On the basis of this, a structural cause for an error to occur between analysis result and AISC formula in the deck of module in which a stud was installed was analysed, and measures for considering this were suggested. Besides, an analysis model with the variables of measures for improving the floor vibration performance of modular housing to be studied was established. And measures having excellent vibration performance and economic feasibility were suggested through vibration response analysis and economic evaluation.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.34-45
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• 2004

Existing Semangeum's water balance analysis simplifies whole basin to single basin and achieved volume of effluence that produce by Kajiyama way to foundation. But Semangeum is complicated and various rice-wine strainer supply system. And there is difficulty to apply as elastic when water balance element is changed at free point. Divided to unit possession station for suitable water balance analysis model application to Semangeum in this study. And developed basin water balance model of GIS base that can do details analysis is bite about development and transfer of an appropriation in the budget of basin water resources. Achieved study including abstraction and concept design that use UML (unified modeling language) diagram for details analysis, stream network composition for rice-wine strainer supply system application, preprocessing of GIS base and postprocessing module development, model revision and verification etc. Support of this water balance analysis model is available to establish efficient water resources administration plan through outward flow process analysis of water resources. And support is considered to be possible in more convenient and, reasonable water resources administration way establishment by minimizing manual processing in systematic water resources government official to user and support diversified analysis system.

• The Journal of the Acoustical Society of Korea
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• v.39 no.4
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• pp.351-363
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• 2020

Launch vehicles are subject to airborne acoustic loads during atmospheric flight and these effects become pronounced especially in transonic region. As the vibration due to the acoustic loads can cause malfunction of payloads, it is essential to predict and reduce the acoustic loads. In this study, a complete process has been developed for predicting airborne vibro-acoustic environment inside the payload pairing and subsequent noise reduction procedure employing acoustic blankets and Helmholtz resonators. Acoustic loads were predicted by Reynolds-Averaged Navier-Stokes (RANS) analysis and a semi-empirical model for pressure fluctuation inside turbulent boundary layer. Coupled vibro-acoustic analysis was performed using VA One SEA's Finite Element Statistical Energy Analysis (FE-SEA) hybrid module and ANSYS APDL. The process has been applied to a hammerhead launch vehicle to evaluate the effect of acoustic load reduction and accordingly to verify the effectiveness of the process. The presently developed process enables to obtain quick analysis result with reasonable accuracy and thus is expected to be useful in the initial design phase of a launch vehicle.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.3
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• pp.257-266
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• 2007

The research on red tide is generally in progress through field work, such as the naked eye and sampling. It was difficult to forecast exactly the course, from appearance of red tide to disappearance. with the established ways of investigation and analysis. Accordingly it is need to analyze environmental factors in time and space, the appearance of red tide and the path of its migration by more objective and scientific methods. In this study, GIS is applied to analyse the space character of red tide and the interpolation of IDW(Inverse Distance Weight) is applied to assume the density distribution of red tide after gather data by using Arc/Info. After IDW interpolation, the sea area occurred over 1,000 cells/ml of red tide density is extracted with CON and SUM Function of Grid Module, and the density of the sea area is accumulated daily. As a result of this study, the distribution condition of red tide is found timely and spacially by applying GIS to the sea area of red tide, the results indicated that the spatial density and the cumulative frequency about the origin of red tide using GIS, the sea area demonstrated that the maximum density and the maximum frequency varied significantly over the Nammyun of Namhae-Is. with the maximum frequency being 49 times. accordingly if data about the areas of red tide will occur from the present are accumulated, the shifting route of red tide occurrence and extinction can be predicted.

• Membrane Journal
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• v.15 no.4
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• pp.310-319
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• 2005

This paper describes the preliminary study on the development of multi-stage membrane demonstration plant for removal of carbon dioxide from flue gas stream being emitted from LNG boiler in thermal power generation plant. The prerequisite requirement is to design and develop the membrane process producing a $99\%\;CO_2$ with $90\%$ recovery from LNG flue gas of 1,000 $Nm^3$/day. Asymmetric polyethersulfone hollow fiber membranes and membrane modules developed in this laboratory[1] were used in this study. Using the permeation data for the hollow fiber membranes, modelling on the membrane module and multi-stage membrane process was done to meet the requirement condition of the process design. The effects of the operating pressure of feed and permeate side and feed concentration on $CO_2$ purity and recovery were investigated experimentally with the developed hollow fiber modules. These experimental results matched well with theoretical modelling results.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.42-48
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• 2012

In this study, experiment on phosphorus removal was performed by using microbubble liquid film flotation tank with microbubble module. After dissolving gas and liquid in dissolving tank, microbubble liquid film system created microbubbles in equal size under fixed low pressure. After being passed through $A_2O$ and m-$O_3$ process, secondary treatment wastewater was used as influent in phosphorus removal process. When the T-P concentration of influent was 2.89 mg/L, alum(8%, 30 mg/L) was injected into a microbubble flotation tank, the treatment resulted 94% of T-P removal rate. Remaining T-P concentration was less than 0.2 mg/L, which is in accord with the effluent quality standard. Seasonal variations in water temperature showed no differences in T-P removal property. When the inflow concentration of SS was 1.0 mg/L or more, it served as coagulation nuclei in the coagulation process. In that condition, average T-P removal rate was higher than 97%. When 50% of floated scum was returned, coagulator Al included in scum assisted the injected coagulator and maximized the coagulation efficiency of pollutant. In such treatment, the T-P concentration was measured as 0.18 mg/L and satisfied the outflow water quality standard, which is 0.2 mg/L or less.

• Archives of design research
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• no.16
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• pp.101-110
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• 1996

CHOOSA GORACK which is a typical example of traditional houses in the CHO SEON dynasty consists of the four terraced builfing group. Among those,SADANG CHAI are located in the highest level,and SADANG CHAI and SADANG CHAI are toward south direction.It means that building orientation and level were influenced by the distinction of social level and the idea of ancester worship. Floor and ceiling level in the same building is different which was caused by the distinetion of social level in the CHO SEON dynasty and an ariental dual as a variety of openings,exposed ceilings,and furniture against a wall were creating a typical Korean visual harmony. Although the furniture and equipments were very important elements in ONDOL BANG the occupance ratio of these were low because the free space in BANG should be utilized effectively to accommodate the space variation.Both an AN CHAI and SARANG CHAI were composed by the standard space module called KAN.And interior elements were established by several factors such as the human scale,the behavior pattern in traditional sitting life style, and the lumber size of post and lintel construction of Korean house.BANG and DAE GHUNG, composed of KAN,were expanded and arranged side by side so that the natural light and ventilation through them could be used in the result of the kind of lay out,traffic circulation was disturved.In conclusion,CHOOSA GOTACK was formed by the sirect effice of the KOREAN penisula. However this study was based on one sample. It may not enough to deduct soild conclusion.Therefore continuous and farher study is needed for the sestemane evaluation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3708-3713
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• 2015

The objective of this study is to numerically investigate the heat transfer rate for evaluating the thermal performances of the stack thermal system using the commercial software. In order to perform this, the cooling performances of the stack system for fuel cell electric vehicle were tested under both driving road conditions including the general driving road and uphill driving road and operating conditions with and without of the air conditioning system. The heat transfer rate of the stack radiator for the stack system was increased with the increase of the inlet air flow velocity. The heat transfer rate of the stack radiator increased by 105.3% at the coolant flow rate of 20 l/min and 221.3% at the coolant flow rate of 120 l/min with the increase of the air flow velocity from 2 m/s to 10 m/s. $9.45^{\circ}C$ of inlet coolant temperature of the stack radiator at the severe driving condition of the slope of 8% and velocity of 50 km/h showed higher 85.3% than $5.1^{\circ}C$ of inlet coolant temperature at the general driving condition of the slope of 0% and velocity of 120 km/h. In addition, as the fuel cell electric vehicle with the air conditioning system operation was driving under severe uphill driving condition, the radiator coolant temperature for a stable stack operation could be exceeded over $70^{\circ}C$.