• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.664-675
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• 1990

In this study, the performance test and heat transfer experiment for a 4 cylinder and 4-cycle turbocharged gasoline engine were carried out in order to measure the heat transfer coefficient at the inner wall of the combustion chamber. From the result of heat transfer experiment, the energy balance of the fuel energy and the overall efficiency of the turbocharger were calculated, The variation of them was investigated as well with the engine operation conditions.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1562-1568
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• 2014

Based on the average method and the geometrical technique to calculate the average value, the average model of the open-loop step-up converter in CCM operation is established. The DC equilibrium point and corresponding small signal model is derived. The control-to-output transfer function is presented and analyzed. The theoretical analysis and PSIM simulations shows that the control-to-output transfer function includes not only the DC input voltage and the DC duty cycle, but also the two inductors, the two energy-transferring capacitors, the switching frequency and the load. Finally, the hardware circuit is designed, and the circuit experimental results are given to confirm the effectiveness of theoretical derivations and analysis.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.4 s.235
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• pp.519-525
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• 2005

The operation of a low temperature differential model stirling engine is tested and analyzed by Simple analysis model. The heat transfer coefficients are required for Simple analysis, and the coefficients are determined by coinciding the P-V diagram of analysis to the diagram of experiment. The results show a good agreement. However the heat transfer coefficients are quite high by comparison with the ordinary forced convective heat transfer cases.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.4
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• pp.193-203
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• 2012

This study analyzed regular transportation costs between port warehouses and processing plants and between processing plants and central distribution centers and further transportation costs relations according to empty transfer rates in each circulation by examining the distribution routes of imported grain including wheat, barley, corn, and soybean, namely port warehouses, processing plants, and central distribution centers. Based on the results, the study compared and reviewed the logistics transportation costs. The analysis results of the alternative model show that logistics operational costs could be considerably cut down by introducing a flexible vehicle transportation operational method, which is to change the vehicle loading parts for proper substitute transportation after unloading and transport them to other locations such as central distribution centers instead of returning empty, as an alternative to high operational costs deriving from empty vehicle operation in each circulation after unloading items in case of transportation of imported grain and processed items. The results allow for a more realistic approach to general problems with large-scale distribution network operation and provide a theoretical foundation to serve as a guide to establish policies for corporate operation of imported grain logistics systems.

• Korean Journal of Construction Engineering and Management
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• v.15 no.6
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• pp.53-62
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• 2014

Recently, the number of super high-rise building projects have been increased after recovering from international financial crisis. In super high-rise building project, vertical lifting is critical to overall project productivity, due to its limited lifting equipments. Also for projects which buildings' height are higher than 400m, transfer operation in lifting is inevitable because of lifts' maximum lifting height. In transfer operation, setting a transfer floor is essential for saving lifting time of resources. In this research, using discrete event simulation modeling with AnyLogic 7.0 software and metaheuristic optimization with OptQuest software, the method of optimizing a transfer floor for workers during the morning peak time is proposed. Comparing to the result of the case which transfer floor is designated to the middle floor, setting optimized transfer floor significantly decrease the total lifting time of workers. By using proposed simulation and optimization tool, saving budget and time through increasing available working hour is expected.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1225-1228
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• 2005

This paper compares the differences between Java virtual machine and x86 processor in data transfer viewpoint. Memory models of JVM and x86 are analyzed and the data transfer paths are identified. As all operations must be performed to the values on operand stack, a great many data transfer operation is unavoidable in JVM. We also lists the number of data transfer operations necessary for executing some typical high-level language statements including assignment, arithmetic, conditional, and iterative statements.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1305-1310
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• 2016

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2384-2389
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• 2007

The 2nd order response surface method (RSM) has been carried out to get optimum thermal design for enhanced heat transfer on square channel with bleed holes. The RSM was used as an optimization technique with Reynolds-averaged navier-stokes equation. Turbulence model for heat transfer analysis used RNG k-epsilon model. The wall function used enhanced wall function. Numerical local heat transfer coefficients were similar to the experimental tendency. Two design variables such as attack angle of rib (${\alpha}$), rib pitch-to-rib height ratio (p/e) were chosen. Operation condition considered bleeding ratio per bleed hole ($BR_{hole}$). A response surface were constructed by the design variables and operation condition. As a result, adjusted $R^2$ was more than 0.9. Optimization results of various objective function were similar to heat transfer in channel with and without bleed flow. But friction factor was lower than channel without bleed flow.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5D
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• pp.627-634
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• 2009

The BTL (Build-Transfer-Lease) contract of construction project serves as a part for early establishment of industrial foundation for social overhead capital. However, project cost of BTL contract is focused on initial construction cost. Accordingly, operation cost is lowly evaluated because there is no standard criterion for estimating maintenance cost for the facility. The low operation cost can be a factor that reduces service quality of facility operation. This study suggests a resonable method for estimating cost and manpower in the operation phase by using the existing practical data for wastewater treatment plant by BTL contract. The results of the study can be used for evaluating rough operation cost and manpower of similar plant project by facility size.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.189-192
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• 2003

Electrical power in satellite system should persistently satisfy specified power requirement even though that happen the failure of solar array string or battery cell during the mission operation. In this study, the solar array and battery of GEO Communication Satellite with 3kW capacity are designed, and energy balance analysis according to power operation mode are performed to meet specified power capacity at the transfer orbit