• Journal of Korea Multimedia Society
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• v.21 no.6
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• pp.649-658
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• 2018

In this paper, we propose a mechanical contact inner tap inspection system that can inspect the defect of the inner tap immediately after inner tap is processed within the machining center. The inspection module has the collet chuck structure, so it can mounted on the main spindle of the machining center during inspection. It was developed with a focus on inspection for tap having 20 mm depth which is primarily fabricated in automotive parts and has a double sided PCB-type control system including sensing function based on Zigbee module, micom and IR sensor for wireless transmission of measured data with low power operation, and also a battery for supplying electric power. The current consumption is 46.8mA in the inspection operation mode and 0.0268mA in the power saving mode for 3.7V of the applied power source, so that 30,000 times or more inspection can be performed with assumed 5 seconds inspection time for one tap. Experiments in test jig system and actual machining center confirm that the proposed inner tap inspection system can be applied to the batch process of simultaneous inspection after tapping in the machining center.

• Journal of Multimedia Information System
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• v.6 no.4
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• pp.239-244
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• 2019

With the development of Cyber-Physical Systems(CPS), several technologies such as automation control, automotive and intelligent house systems have been developed. To enable communication among various components of such systems, several wired and wireless communication protocols are used. The Controller Area Network(CAN) is one of such wired communication protocols that is popularly used for communication in automobiles and other machinery in the industry. In this paper, we designed and implemented a response time analysis system for CAN communication. The reliable data transfer among various electronic components in a significant time is crucial for the smooth operation of an electric vehicle. Therefore, this system is designed to conveniently analyze the response time of various electronic components of a CAN enabled system. The priority for transmission of the messages in the CAN bus is determined by the message identifier. As the number of nodes increases the transmission of low priority messages is delayed due to the existence of higher priority messages on the bus. We used Raspberry Pi3 and PiCAN2 board to simulate the data transfer for studying the comparative delay in low priority nodes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2311-2316
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• 2009

Lately, in the automotive market appeared keywords such as convenience, safety in presentation and increase importance of pan of vehicle. Accordingly, the use of many electronic devices was required essentially and communication between electronic devices is being highlighted. Various devices such as controllers, sensors and multimedia device(audio, speakers, video, navigation) in-vehicle connected car network such as CAN, MOST. Modem in-vehicle network managed and operated as purpose of each other. In this Paper, intelligent car navigation considering convenience and safety implement on MOST Network and present system to control CAN Network in vehicle.

• Journal of Adhesion and Interface
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• v.7 no.4
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• pp.10-12
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• 2006

The successful use of adhesively bonded parts depends on the defect-free bond of the components. Therefore it is necessary to detect relevant faults and defects in an early state of the production. A 100% test should be pursued, but especially at complicated structures the detection of defects is not easy. Possible testing methods, which show a high potential for the NDT of adhesively bonded parts, are thermography based NDT methods. At present mainly two different procedures of active thermography are being used: Pulse and Lock-In Thermography. With pulse thermography the examined material is warmed up with a short energy pulse (light, eddy current or ultrasonic pulse) and the heat response is recorded after a certain time. The result is an infrared image which indicates material defects in different depths. This paper presents a variety of images showing the capability of Lock-In Thermography to image subsurface defects. Several examples of adhesives joints qualify the ultrasonic Lock-In-Thermography for the in-process quality control for adhesive bonded components.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.1
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• pp.25-32
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• 2005

Falling film heat transfer has been widely used in many applications in which heat and mass transfer occur simultaneously, such as evaporative coolers, cooling towers, absorption chillers, etc. In such cases, it is desirable that the falling film spreads widely on the surface forming thin liquid film to enlarge contact surface and to reduce the thermal resistance across the film and/or the flow resistance to the vapor stream over the film. In this work, the surface is treated to have thin porous layer on the surface. With this treatment, the liquid can be spread widely on the surface by the capillary force resulting from the porous structure. In addition to this, the liquid can be held within the porous structure to improve surface wettedness regardless of the surface inclination. The experiment on the evaporative cooling of an inclined surface has been conducted to verify the effectiveness of the surface treatment. It is measured that the evaporative heat transfer increases about $50\%$ by the porous layer treatment as compared with that from orignal bare surfaces.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.277-285
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• 1998

This paper presents the deformation characteristics of the moving pressure plate in a balanced type vane pump that widely used automotive power steering systems. Moving pressure plate can control the clearance between rotor and plate in accordance with load pressure variation; it always guarantees that pump to have optimal volumetric efficiency. In this paper, firstly, we calculate the acting force on the pressure plate, which is used to determine the angular position and load condition for analyzing the deformation of pressure plate. Secondary, finite element method is used for the deformation analysis. As results of acting force analysis, it is found that maximum difference of forces occurs at angular position 28$\circ$ from the small arc center of cam ring and load pressure is a dominant factor to affect acting force variation. The deformation of pressure plate increases as load pressure increases. At high load pressure, the deformation of pressure plate becomes larger than the initial clearance between rotor and plate. Therefore, it is required to design the plate for controlling the deformation.

• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.193-199
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• 2017

Mechanical tappet is used to reduce the cost and friction loss compared with hydraulic tappet. But the mechanical tappet doesn't have the ability to control the clearance between cams and valves and is selected by measuring the distance between valves and cams in order to minimize the clearance of valves by considering thermal expansion of valves. So, the valve clearance is nearly zero after fully warming-up periods, but there is valve clearance before warming-up. Especially at cold condition, the clearance is relatively large and can bring about some problems. In this study, the valve motions like lift, velocity, seating velocity and bouncing height were studied at various valve clearance conditions by experiment and analysis. As the valve clearance increases, the ramp area becomes shorten and it causes the valve train motion to have bad effects.

• Journal of Drive and Control
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• v.16 no.4
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• pp.87-92
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• 2019

Rotary dampers are damping devices which provide high resistance to shaft rotation. Rotary dampers are being used in various areas to enable the gentle opening and closing of the rotation motion relative to home furniture, industry machinery and automotive parts. Rotary dampers can be installed directly at the rotating point of a various part and can achieve uniform, gentle movement which increases quality and value of products. And generally, the silicone fluid is used as the damping medium because of its stable viscous properties. The movement of these little decelerators can be achieved with a high viscosity of working fluid and throttles installed in the body of the rotary damper. The damping force can be achieved clockwise, anti-clockwise or in both directions according to the structure of the orifices or throttles. In this paper, the torque performances of the rotary damper containing air in the working fluid were studied. For this purpose, the torque characteristic of the rotary damper according to the variation of various operating conditions such as clearance of leakage, dimensions of groove orifice, content ratio of air, etc., were simulated with AMEsim software.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.2
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• pp.185-190
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• 2016

This paper deals with analysis of the characteristics of mobile robot's motion by automatic detection of markers on a robot using a camera. Analysis of motion behaviors according to parameters is important in developing control algorithm for robot operation or autonomous navigation. For this purpose, we use four chessboard patterns on the robot. Their location on the robot is adjusted to be on single plane. Homography is used to compute the actual amount of movement of the robot. Presented method is tested using P3-AT robot and it gives reliable results.

• Journal of Mechanical Science and Technology
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• v.17 no.9
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• pp.1249-1260
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• 2003

This present work focuses on the influence of nonlinearities associated with impact on the rocking behavior of a rigid body block subjected to a two-dimensional excitation in the horizontal and vertical directions. The nonlinearities in rocking system are found to be strongly dependent on the impact between the block and the base that abruptly reduces the kinetic energy. In this study, the rocking systems of the two types are considered : The first is an undamped rocking system model that disregards the energy dissipation during the impact and the second is a damped rocking system, which incorporates energy dissipation during the impact. The response analysis is carried out by a numerical method using a non-dimensional rocking equation in which the variations in the excitation levels are considered. Chaos responses are observed over a wide range of parameter values, and particularly in the case of large vertical displacements, the chaotic characteristics are observed in the time histories, Poincare sections, the power spectral density and the largest Lyapunov exponents of the rocking responses. Complex behavior characteristics of rocking responses are illustrated by the Poincare sections.