• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.395-397
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• 1999

This paper presents a method of improving the power factor and the waveform of A.C line currents and the out waveforms of AC to DC fully bridge converter systems which is achieved by connecting converters in series and parallel. The results of simulation show that the power factor and the source voltage and current waveforms are improved by the method of connecting converter in series, and the controlled input voltage and current waveform using a current limit controller.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.5
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• pp.407-413
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• 2014

The diesel engine and reduction gear combination is one of the common propulsion system in a naval vessel. Since the diesel engine has torsional vibration caused by reciprocating motion of the mass and gas pressure force of the cylinder, high cycle torsional fatigue can be occurred. Therefore, ROK navy restricts the maximum stress of the propulsion shaft according to MIL G 17859D. In this paper, the root cause for the failure of the diesel engine and reduction gear connecting shaft occurred in typical naval vessel is investigated based on the measured bending and torsional moment according to MIL G 17859D procedure.

• Journal of the military operations research society of Korea
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• v.29 no.1
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• pp.43-56
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• 2003

This paper is intended to investigate the Build-up Method of SCM(Supply Chain Management) Connection applying EC Standard. SCM helps companies plan and supply to meet customer demand. SCM is the only solution available today that enables an organization to strategize, plan and execute a company's buy, make, move, store, fulfill and service business processes across multiple enterprises for total profitability. The research of modern scientists has thrown new light on the subject. However, the study of SCM for EC Standard has been strangely neglected by critics. Consequently, existing SCM systems, which require to introduce the functions of EC, need to be changed. Summarizations of the main points that have been analyzed in this paper are as follows:. the sharing information for connection and the Rosetta-net standard of the existing SCM system(Order management module(PIP 3A4) of the Rosetta-net specifications for connection by the Rosetta-net). Finally, it shows the process of the gateway for connecting among the existing SCM systems.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.4
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• pp.66-74
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• 1990

Friction between piston-ring assembly and cylinder wall of a spark ignition engine was evaluated under various engine operating conditions utilizing a grasshopper linkage system. The friction force was estimated by the force balance relation at the small end of connecting rod. Three forces were chosen to be measured for the objective. They were gas pressure inside the cylinder, inertia force of the piston-ring assembly, and the force exerted by the connecting rod. These forces were measured by a piezo type pressure sensor, an accelerometer and strain gauges, respectively. Comparisons were made with the frictional force evaluated by the conventional method where the assumption of constant rotational speed of engines was adopted. Due to the variation of rotational speed of engines, the conventional method was found to lead to a large error in the evaluation of the frictional force.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.11a
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• pp.267-270
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• 1998

Current valve protection cover had problem that the hight of cover cap and road level could not match when the road was repaired and overcovered. But new developed device can solve this problem by forming several grooves in the connecting pipe. This device is devided into col=netting pipe (down side) and cap part.(upper side) On the outside diameter of connecting pipe, several horizontal grooves and two vertical grooves are formed. Through the horizontal grooves, the hight of cap part ran be adjusted with ground level. Therefore, this device can help easy maintenence in running water pipe.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.1-10
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• 1994

By applying of total electric capacitance method on engine connecting rod bearing during engine operating, the influence of engine operating conditions and lubricants on bearing oil film thickness was investigated. Minimum oil film thickness increases with kinematic viscosity, but as increasing of viscosity, the increasing ratio of film thickness is reduced. Also minimum oil film thickness increases with engine speed but there is a limit. Above this limit, film thickness decreases in opposition because of crankshaft inertia. As increasing of engine torque and oil temperature, munimum oil film thickness decreases linearly. For non-Newtonian oils, the correlation between $100{\circ}C$ kinematic viscosity and munimum oil film thickness is very poor.

• Education of Primary School Mathematics
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• v.5 no.1
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• pp.41-55
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• 2001

The purpose of this study was to compare and analyze the curricula of kindergarten and elementary school and to present a plan for connecting the two curricula. The curricula emphasized mathematical thinking and problem solving instead of fragmentary knowledge and adopted the streamed curriculum based on children’s ability and interest. And both of them consisted of number and operation, geometry, measurement, statistics, and put emphasis on activity such as real life experience, play, manipulation of concrete objects, and communication. However, there are some kinds of differences between them, because the kindergarten curriculum is not included in the common curriculum, from 1st grade to 10th grade. Thus, this study recommended several ideas based. Thus, this study recommended several ideas based on theories to connect the mathematics curricula of kindergarten and elementary school.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.207-211
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• 2015

In this paper, 2 kinds of models about bike frame are simulated with static structural analysis. A bike frame with diamond type is compared with another model that Down tube is eliminated from original diamond frame. About both types of models, Property of a material and conditions of restriction & load are the same. This study shows reinforcement effects of a partial frame by adding down tube and impacts generated by applying a load at the frame such as weak points & high stress parts as well as expected deformation. The structural result of this study indicates that the equivalent stress or total deformation decreases by 57.1% or 36.4%, respectively. Also stress concentration sites are leg connecting parts, front/rear wheels fixed region and Max deformation is generated from Seat tube. In conclusion, A Down tube is highly efficient as reinforcement than frame without non down tube. Furthermore, The safety rises in case of reducing top tube thickness and increasing a reinforcement at leg connecting parts or concentration regions.

• Smart Structures and Systems
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• v.15 no.5
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• pp.1293-1309
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• 2015

3D two adjacent buildings with different heights founded in different kinds of soil connected with viscous dampers groups, with especial arrangement in plane, were investigated. Soil structure interaction for three different kinds of soil (stiff, medium and soft) were modeled as 3D Winkler model to give the realistic behavior of adjacent buildings connected with viscous dampers under various earthquake excitations taking in the account the effect of different kinds of soil beneath the buildings, using SAP2000n to model the whole system. A range of soil properties and soil damping characteristics are chosen which gives broad picture of connected structures system behavior resulted from the influence soil-structure interaction. Its conclusion that the response of connected structures system founded on soft soil are more critical than those founded on stiff soil. The behavior of connected structures is different from those with fixed base bigger by nearly 20%, and the efficiency of viscous dampers connecting the two adjacent buildings is reduced by nearly 25% less than those founded on stiff soil.

• Journal of Power System Engineering
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• v.12 no.1
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• pp.66-71
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• 2008

Alumium alloys hot forging process are gaining increased acceptance in the automotive and electronic industries and hot forging is one of the most efficient manufacturing method for mass product parts. It has been investigated the microstructures and mechanical properties of Al-11.7Si-0.5Mg (KNT40-T6)alloy fabricated by hot forging process for development of connecting rod in this study. The microstructure of hot forged specimen was composed of eutectic structure of alumimum solid solution and $Mg_2Si$ precipitates. The tensile strength of solutionized Al-11.7Si-0.5Mg alloy was 217MPa. This alloy showed a good corrosion resistance using electrochemical polarization test.