• Journal of Environmental Impact Assessment
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• v.24 no.5
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• pp.407-419
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• 2015

The unit load of paddy field was estimated by several methods and compared in this study. Four year field study was conducted at the paddy fields located in Yeongsan river and Sumjin river basins. The unit load was estimated by four methods; (1) averaging field monitored load; (2) NIER (National Institute of Environmental Research) method which use EMC(Event Mean Concentration) and runoff ratio of rainfall groups with rainfall weighting factors; (3)method using EMC determined by best fit probability distribution; (4)method using arithmetic mean EMC and runoff ratio. The result of this study showed that the unit loads of water quality constituents by field monitoring was similar to those of NIER method whereas those by probability distribution(log-normal, gamma) method were less than unit loads of NIER method. The unit loads by arithmetic mean EMC and runoff ratio were larger than those by NIER method. The unit load by NIER method showed higher BOD, COD, SS, lesser T-N, and similar T-P values when compared to unit loads determined by MOE in 1995.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.948-953
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• 2002

The electric power load during the peak time in summer is strongly affected by cooling load, which decreases the preparation ratio of electricity and brings about the failure in the supply of electricity in the electric power system. The ice-storage system and heat pump system are possible solutions to settle this problem. In this study. the method of estimating temperature and humidity to forecast the cooling load of ice-storage system is suggested, then the method of forecasting the cooling load using fuzzy logic is suggested by simulating that the cooling load is calculated using actual temperature and humidity. The forecast of the temperature, humidity and cooling load are simulated, and it is shown that the forecasted data approach to the actual data. Operating the ice-storage system by the forecast of cooling load with night electric power will improve the ice-storage system efficiency and reduce the peak electric power load during the summer season as a result.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.128-129
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• 2016

This study is to categorize the loading of multiple persons on a vertical building elements into three types to test the size of crowd pressure under each loading patterns. The loading patterns is divided under the combination of loading method and loading persons. The loading method is categorized into the method of instantaneous loading of hand on a force plate and the method of continuous loading. The loading persons has been composed of 1~5 persons under the loading patterns. The loading patterns is also divided into lateral loading, longitudinal loading, and agglomeration loading. The subject group has been composed of 12 males in 20s. The load measurement device(size 1800×600×36mm, capacity 20kN, rigidity 28kN/cm) has been designed and manufactured directly. To eliminate the difference of individual, the size of crowd pressure has been converted into the strength to weight ratio (maximum load/weight) for computation. The strength to weight ratio in lateral loading was about 0.91 under instantaneous loading and about 0.47 under continuous loading. The strength to weight ratio in longitudinal loading was about 0.65 under instantaneous loading and about 0.36 under continuous loading. The strength to weight ratio in agglomeration loading was about 0.65 under instantaneous loading and about 0.36 under continuous loading.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.295-297
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• 2000

In case of power demand forecasting the most important problem is to deal with the load of special-days, Accordingly, this paper presents a method that forecasting special-days load with regression models and neural networks. Special-days load in summer season was forecasted by the multiple regression models using weekday change ratio Neural networks models uses pattern conversion ratio, and orthogonal polynomial models was directly forecasted using past special-days load data. forecasting result obtains % forecast error of about $1{\sim}2[%]$. Therefore, it is possible to forecast long and short special-days load.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.3
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• pp.113-122
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• 2015

HVAC&R systems account for more than 50% of the energy consumption of buildings. The purpose of this study is to propose an optimal design method for the HVAC&R system and to examine the possibility for the energy conservation of a selected system. The energy demand for cooling and heating is determined by using TRNSYS and HEET. By an interaction between total system efficiency and cooling-to-heating load ratio, the optimal HVAC&R systems will be decided. The results showed that this proposed method is significantly capable of determining optimal system and building design for saving energy.

• Steel and Composite Structures
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• v.33 no.3
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• pp.375-388
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• 2019

This paper aims to investigate the axial load behavior and stability strength of square tubed steel-reinforced concrete (TSRC) columns. Unlike concrete filled steel tubular (CFST) column, the outer steel tube of a TSRC column is mainly used to provide confinement to the core concrete. Ten specimens were tested under axial compression, and the main test variables included length-to-width ratio (L/B) of the specimens, width-to-thickness ratio (B/t) of the steel tubes, and with or without stud shear connectors on the steel sections. The failure mode, ultimate strength and load-tube stress response of each specimen were summarized and analyzed. The test results indicated that the axial load carried by square tube due to friction and bond of the interface increased with the increase of L/B ratio, while the confinement effect of tube was just the opposite. Parametric studies were performed through ABAQUS based on the test results, and the feasibility of current design codes has also been examined. Finally, a method for calculating the ultimate strength of this composite column was proposed, in which the slenderness effect on the tube confinement was considered.

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.35-40
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• 2016

OBJECTIVES : The objective of this study is to analyze the nonlinear behavior of block pavements using multi-load level falling weight deflectometer (FWD) deflections. METHODS : Recently, block pavements are employed not only in sidewalks, but also in roadways. For the application of block pavements in roadways, the structural capacities of subbase and subgrade are important factors that support the carry traffic load. Multi-load level FWD testing was conducted on block pavements to analyze their nonlinear behavior. The deflection ratio due to the increase in load was analyzed to estimate the nonlinearity of block pavements. Finite element method with nonlinear soil model was applied to simulate the actual nonlinear behavior of the block pavement under different levels of load. RESULTS : The results of the FWD testing show that the center deflections in block pavements are approximately ten times greater than that in asphalt pavements. The deflection ratios of the block pavement due to the increase in the load range from 1.2 to 1.5, indicating that the deflection increased by 20~50%. The material coefficients of the nonlinear soil model were determined by comparing the measured deflections with the predicted deflections using the finite element method. CONCLUSIONS : In this study, the nonlinear behavior of block pavements was reviewed using multi-load level FWD testing. The deflection ratio proposed in this study can estimate the nonlinearity of block pavements. The use of nonlinear soil model in subbase and subgrade increases the accuracy of predicting deflections in finite element method.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.127-133
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• 2002

The objective of this study is to investigate fatigue life and fatigue crack propagation behavior The experiment of fatigue life for MMC have been carried out for the stress ratio R＝0.1 at 20Hz. Fatigue lift limit of AC4CH alloy is about 70 ㎫ and Fatigue limit of MMC has been increment to 120 ㎫, therefore, fatigue limits of MMC is about 71 % higher than that of AC4CH alloy Crack propagation tests on half-size CT specimen of thickness 12.5mm were conducted by using sinusoidal waveform. The crack length was monitored by compliance method. Test conditions were at 0.1 and 0.05 of load ratio at 10Hz of loading frequency and test load was 2.3kN. The effects of stress ratio on the fatigue crack propagation behavior for MMC was discussed within the Paris law. As the results of this study, Fatigue crack propagation increased with increasing the load ratio.

• Structural Engineering and Mechanics
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• v.12 no.1
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• pp.1-16
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• 2001

A reliable and accurate method has been developed to predict the flexural deformation response of structural concrete members subject to service load. The method that has been developed relates the extent of concrete cracking, measured as a function of the magnitude of applied moment in a member, to the reduction in the effective moment of inertia of cracked reinforced concrete members under service load conditions. The ratio of the area of the moment diagram where the moment exceeds the cracking moment, to the total area of the moment diagram for any loading, provides the basis for the calculation of the effective moment of inertia. This ratio also represents mathematically a probability of crack occurrence. Verification of this method for the determination of the effective moment of inertia has been achieved from an experimental test program, and has included beam tests with different loading configurations, and shear wall tests subjected to a range of vertical and lateral load levels. Further verification of this method has been made with reference to the experimental investigation of other recently published work.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.752-757
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• 2001

To reduce stress concentration around the intersection between a spherical pressure vessel and a cylindrical nozzle under various load conditions using less material, the optimization for the distribution of reinforcement has researched. The ranked bidirectional evolutionary structural optimization(R-BESO) method is developed recently, which adds elements based on a rank, and the performance indicator which can estimate a fully stressed model. The R-BESO method can obtain the optimum design using less iteration number than iteration number of the BESO. In this paper, the optimized intersection shape is sought using R-BESO method for a flush and a protruding nozzle. The considered load cases are a radial compression, torque and shear force.