• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.168-174
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• 2009

High water vapour content in air can cause a number of problems as for human or surrounding materials. For human a high water vapour can create physiological stress, discomfort, and also can encourage ill health. While, the cause for the environment is can accelerate the corrosion of metals, accelerate the growth of spores and mould, can reduce the electrical resistance of insulators and etc. Desiccant systems have been proposed as energy saving alternatives to vapor compression air conditioning for handling especially the latent load and also sensible load. Use of liquid desiccants offers several design and performance advantages over solid desiccants, especially when solar energy is used for regeneration. The liquid desiccants contact the gas inside the packed tower of liquid desiccant solar cooling system and the heat transfer and mass transfer will occur. This thesis is trying to study the characteristics inside the packed tower of dehumidifier systems. This characteristics consist of mass transfer rate, heat transfers rate, human comfort and energy that consume by the system. Those characteristics were affected by air flow rates, air temperature and humidity, and desiccant temperature and all that variation will influence the performance of the systems. The results of this thesis later on can be used to determine the best performance of the systems.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.107-114
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• 2003

This study investigated the effect of 2-methoxy ethanol (2-Me) non-solvent as additive included in casting solution. Macroporous polymer membranes were prepared by using polyethersufone (PES)/N-methyl-2-pyrrolidone (NMP)/2-Me casting solution and water coagulant. The phase separation co-process of the vapor-induced phase separation (VIPS) and liquid-induced phase separation (LIPS) were used by means of membrane preparation method. The pore size and pore size distribution were controlled with additive (non-solvent), and measured with Automated Perm Porometer. By increasing additive (non-solvent) in the casting solution, the membranes produced changed from finger structure to sponge structure. That is due to the different diffusion rates. At slow diffusion process, sponge-like structure was formed and at fast diffusion process, finger-like structure was formed. Also relative humidity, evaporation time, temperature of casting solution and coagulation bath etc. had effects on the pore size distribution and the porosity of the membrane.

• Journal of Hydrogen and New Energy
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• v.30 no.6
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• pp.578-584
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• 2019

The occurrence of white plume in the cooling tower is phenomenon that the steam in the air through the cooling tower fan is condensed again by the cold ambient air to become saturated moist air. Accordingly, this can cause many problems like spoiling landscape around the cooling tower, odor of ambient air, falling accident by frozenness in the winter, and traffic accident, etc. This study was to install the heat exchanger in the inside of the cooling tower in order to prevent the white plume phenomenon in the cooling tower without affecting the performance of cooling tower. In addition, this study was to discharge the part of cooling water into the atmosphere through the recirculation of heat exchanger after creating dry air by heating the saturated moist air to the dew point temperature. At that time, this study was to conduct the experimental study in order to secure the optimal design data to prevent the white plume in the cooling tower because it checked the dry·moist temperature and relative humidity in the inside·outside of cooling tower on the moist air, and evaluated the performance of the heat exchanger.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.501-504
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• 2004

This paper proposes degree of hydration based shrinkage prediction model of 40MPa HPC. This model shows degree of hydration which is defined as the ratio between the hydrated cement mass and the initial mass of cement is very closely related to shrinkage deformation. In this study, degree of hydration was determined by CEMHYD-3D program of NIST. Verification of the predicted degree of hydration is performed by comparison between test results of compressive strength and estimated one by CEMHYD-3D. Proposed model is determined by statistical nonlinear analysis using the program Origin of Origin Lab. Co. To get coefficients of the model, drying shrinkage tests of four specimen series were followed with basic material tests. Testes were performed in constant temperature /humidity chamber, with difference moisture curing ages to know initial curing time effect. Verification with another specimen, collected construction field of FCM bridge, was given in the same condition as pre-tested specimens. Finally, all test results were compared to propose degree of hydration based model and other code models; AASHTO, ACI, CEB-FIP, JSCE, etc.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.5
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• pp.47-55
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• 2005

This study was conducted to suggest revegetation character for environment factor of slope. Field test carried out for the man-made slope with three types(0.5cm no net, 3.0cm no net, 3.0cm net) revegetation methods in Hwaseong. Test revegetation plants were Festuca arundinacea, Lolium perenne, Lespedeza cyrtobotrya and Indigofera pseudo-tinctoria M. The result of this study can be summarized as follows; 1. The soil hardness, the soil acidity, and the soil humidity of three types(0.5cm no net, 3.0cm no net, 3.0cm net) revegetation methods were at a suitable value for plants growth. 2. All plant growth index(seedling number, ground coverage, plant height, plant weight, etc) of south slope were better than north slope. But plant growth index of net plots were similar to no net plots. 3. For washout investigation, washout quantity of north slope was plentifully measured from south slope, and 1 amount of rainfall will be big was visible appears plentifully.

• Conservation Science in Museum
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• v.3
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• pp.21-27
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• 2001

In National Central Museum, we recently preserved paper cultural assets, such as ancient maps, books and antique documents etc, to prepare "A Dynamic World of External Relations in Goryeo & Joseon Dynasty". The paper cultural assets generally react sensitively to their environments; temperature, humidity, light and physical force acting. Biological damages, which are caused by microbe, contraction, swelling and damage from insects occurred. Wrinkles on relics, which are made my physical force, stains on relics which are due to moisture, weakening of adhesive strength and damages from insects were found during the recent preservation handling. Therefore we are trying to find out any damage, which could be occurred in paper cultural assets and introduce brief emergency operation to prevent the damages and develop the preservation handling.

• Journal of KIISE:Databases
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• v.33 no.1
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• pp.32-41
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• 2006

In data-centric networks, various data items, such as temperature, humidity, etc. are sensed and stored in sensor nodes. As these attributes are mostly scalar values and inter-related, multi-dimensional range queries are useful. To process multi-dimensional range queries efficiently in data-centric storage, data addressing is essential. The Previous work focused on efficient query processing without considering overall network lifetime. To prolong network lifetime and support multi-dimensional range queries, we propose a dynamic data distribution method for multi-dimensional data, where data space is divided into equal-sized regions and linearized by using Hilbert space filling curve.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.439-439
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• 2015

The temporal and spatial relationship of the weather elements such as rainfall and temperature is closely linked to the streamflow simulation, especially, to the flood forecasting problems. For the study area, Imjin river basin, which has the specific characteristics in geography with river cross operation between North and South Korea, the meteorological information in the northern area is totally deficiency, lead to the inaccuracy of streamflow estimation. In the paper, this problem is solved by using the combination of global (such as soil moisture content, land use) and local hydrologic components data such as weather data (precipitation, evapotranspiration, humidity, etc.) for the model-driven runoff (surface flow, lateral flow and groundwater flow) data in each subbasin. To compute the streamflow in Imjin river basin, this study is applied the hydrologic model SURR (Sejong Univ. Rainfall-Runoff) which is the continuous rainfall-runoff model used physical foundations, originally based on Storage Function Model (SFM) to simulate the intercourse of the soil properties, weather factors and flow value. The result indicates the spatial variation in the runoff response of the different subbasins influenced by the input data. The dependancy of runoff simulation accuracy depending on the qualities of input data and model parameters is suggested in this study. The southern region with the dense of gauges and the adequate data shows the good results of the simulated discharge. Eventually, the application of SURR model in Imjin riverbasin gives the accurate consequence in simulation, and become the subsequent runoff for prediction in the future process.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1180-1185
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• 2006

Modern people spend most of time at indoor space, such as office or classroom. Especially, occupants are exposed to the airtight indoor air quality (IAQ) for a long time, At present, many studies on the air-conditioning systems are more focused on the individual thermal comfort than the thermal efficiency due to increase of the concern of health. There are several factors which are influenced thermal comfort, such as temperature, humidity, convection and air movement, etc. Also, the individual factor, such as age, gender, Physical constitution and habit, should be considered. The 4-way cassette type air conditioner is known to bring out better performance about thermal comfort than the traditional one. This study is performed on the higher ceiling environment than the common buildings or classrooms. Also, this study analyzed on the Indoor thermal comfort by diffusing direction of 4-way cassette air conditioner with various discharge angles, $45^{\circ},\;50^{\circ},\;55^{\circ}$ and $60^{\circ}$. Using a commercial code, FLUENT, three-dimensional transient air thermal flow fields are calculated with appropriate wall boundary conditions and standard $k-{\epsilon}$ turbulence model. Results of velocity and temperature distributions are graphically depicted with various discharge angles.

• International Journal of Advanced Culture Technology
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• v.6 no.4
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• pp.190-194
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• 2018

The runway visual range is one of the important factors that decide the possibility of taking offs and landings of the airplane at local airports. The runway visual range is affected by weather conditions like fog, wind, etc. The pilots and aviation related workers check a local weather forecast such as runway visual range for safe flight. However there are several local airfields at which no other forecasting functions are provided due to realistic problems like the deterioration, breakdown, expensive purchasing cost of the measurement equipment. To this end, this study proposes a prediction model of runway visual range for a local airport by applying convolutional neural network that has been most commonly used for image/video recognition, image classification, natural language processing and so on to the prediction of runway visual range. For constituting the prediction model, we use the previous time series data of wind speed, humidity, temperature and runway visibility. This paper shows the usefulness of the proposed prediction model of runway visual range by comparing with the measured data.