• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.4
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• pp.340-348
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• 2004

The air and refrigerant side heat transfer performances are key parameters to improve heat transfer efficiency of the heat exchanger including the fan performance. Design of the fins, treatment of the tube inside, tube diameter and tube array effect heat transfer performance of the heat exchanger. The heat exchanger is used as a condenser at cooling mode and used as an evaporator at heating mode in the heat pump system. The heat pump system uses R410A as the refrigerant. The heat exchangers are consisted with 7 mm diameter tubes with slit-type fins. The study was conducted with variation of arrangement of the refrigerant path and air flow rate and refrigerant pressure drop and heat transfer rate were measured with a code tester. The capacity of the 3 path heat exchanger is more efficient than 2 or 4 path heat exchangers in heating or cooling modes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1182-1194
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• 2016

The single image dehazing algorithm in existence can satisfy the demand only for improving either the effectiveness or efficiency. In order to solve the problem, a novel variational framework for single image dehazing based on restoration is proposed. Firstly, the initial atmospheric scattering model is transformed to meet the kimmel's Retinex variational model. Then, the green light component of image is considered as an input of the variational framework, which is generated by the sensitivity of green wavelength. Finally, the atmospheric transmission map is achieved by multi-resolution pyramid reduction to improve the visual effect of the results. Experimental results demonstrate that the proposed method can remove haze effectively with less memory consumption.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.373-378
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• 2011

As the number of deeply-underground subway station(DUSS) increases, the safety measures for DUSS have been requested. In this research, Shingumho station (The line # 5, Depth: 46m) has been selected as case-study for the analysis of smoke-spread speed with the different fire strength. Field test data measured for actual fan in DUSS was applied as a condition of a simulation. The whole station was covered in this analysis and total of 4 million grids were generated for this simulation. The fire driven flow was analyzed case by case to compare the smoke-spread effect according to the fire strength. in order to enhance the efficiency of calculation, parallel processing by MPI was employed and large eddy simulation method in FDS code was adopted.

• Journal of Navigation and Port Research
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• v.34 no.9
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• pp.705-709
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• 2010

Buildings nowadays are increasingly expected to need higher and more economic performance requirements. Energy consumption in buildings accounts for over 30% of total energy use. The Building Energy Management System (BEMS) and renewable energy (RE) technologies are considered as a potential measure to improve energy efficiency and reduce use of grid-power. It is, however, a challenge to utilise the intermittent energy supply of RE in building energy systems. This paper presents an experimental study on a RE-embedded BEMS. A control algorithm for the RE-embedded BEMS was designed to maximise the utilisation of RE and eventually to reduce electrical utility bill. The proposed system is tested at a laboratorial chamber with an air conditioner, fan and heater. The contribution of RE in building energy system is discussed to this end.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.367-372
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• 2005

This study primarily is concerned with a new device which has been developed following the international standards to measure the ventilation performance at elevated temperature. This device can measure duration of ventilation, performance of electricity, static pressure at elevated temperature and also it is having provision to measure reversible performances during fire hazards. Invented device is closed circuit type system which is best suited for korean industrial environment with low cost and high efficiency. International standards has been compared and performance testing has been major using BS 7346 which is tested by Warrington Fire Research Centre.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.9
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• pp.3721-3737
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• 2015

3D reconstruction based on binocular data is significant to machine vision. In our method, we propose a new and high efficiency 3D reconstruction approach by using a consumer camera aiming to: 1) address the configuration problem of dual camera in the binocular reconstruction system; 2) address stereo matching can hardly be done well problem in both time computing and precision. The kernel feature is firstly proposed in calibration stage to rectify the epipolar. Then, we segment the objects in the camera into background and foreground, for which system obtains the disparity by different method: local window matching and kernel feature-based matching. Extensive experiments demonstrate our proposed algorithm represents accurate 3D model.

• Journal of Biosystems Engineering
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• v.18 no.1
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• pp.3-14
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• 1993

This study was conducted to obtain basic data which affected engine performance of the power tiller being widely used in the rural area. Among the various factors being influenced engine performance, factors of radiator, of capacity of cooling water, and of efficiency of cooling fan were considered as the major factors in this study. Because diesel engine being used to power tiller are scarce of cooling water, it is over-heated in time of rated power. Therefore, a experiment was performed to determine the capacity of cooling water of engine with circuit system of cooling water adhered.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.61-66
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• 1987

The metals has been used to the electric motor frame and brackets. The purpose of this project is to substitute engineering plastic doter frame for metal because of the demand for small size and environmental reliability. As a result of considering of mechanical strength, heat and injection characteristic of engineering plastics. PBT GF 30 has been selected as the material of electric motor frame including brackets. Design of the frame has been carried out on enough consideration of mechanical strength, heat-resisting and endurance. For the prevention of lower efficiency, the length of airgap between stator and rotor is reduced and for the reduction of vibration, slot combination is changed and the length of stator is increased.

• Journal of Ocean Engineering and Technology
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• v.21 no.3 s.76
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• pp.1-7
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• 2007

In this study, the heat balance test of an engine was conducted, and the heat released to coolant is measured and corrected using a power adjustment factor for high fuel temperature to simulate heat rejection of the engine. An engine-converter matching simulation program which can compute the engine speed, transmission output speed, transmission input and output power is developed from the vehicle, transmission and engine performance curve. With this information and the engine heat rejection characteristics, the engine and transmission heat rejection rates can be determined at given condition. In analyzing the air mass flow, a sub program computing the air mass flow rate from the equation of the pressure balance between cooling fan static pressure rise and pressure losses of cooling components is developed.

• Journal of Applied Reliability
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• v.13 no.1
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• pp.31-44
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• 2013

Recently, due to the high rise of energy costs and environmental problem issues, much attention has been paid to wood pellets. Wood pellets are produced by compressing woody biomass into cylindrical form. Wood pellets are suitable for use at various scales in industrial furnaces for heat production to replace conventional fossil fuel energy sources since the use of wood pellet that is carbon neutral can alleviate global warming. This study presents the result of developing two industrial wood pellet boilers with high safety having capacities of 290kW and 440kW. Efficiency has been improved by using a rotating screw bar grate burner. Special attention has been paid to the improvement of the safety of the wood pellet boilers from backfire by adopting a triple protecting system composed of a rotary feeder, an air curtain, and a backfire protecting DC-fan.