• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.225-232
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• 2007

This work intends to investigate the effects of shift characteristics on the propulsion performance of a manual wheelchair with an automatic transmission. A planetary gear train is employed to generate a two-stage shift automatically, based on the distance traveled from rest. Motion analysis has been performed for measuring kinematic properties of the arm and then the inverse dynamics has been applied for estimating joint forces/torques. Then, a parametric study has been performed to find a set of the shift ratios and the shift intervals for optimizing propulsion performance. Results show that the propulsion performance is closely related to the shift condition. It is found that a short shift interval is desirable for a short distance propulsion. However, an optimum shift interval for a long distance propulsion is inversely proportional to the shift ratio approximately. Consequently, the automatic transmission can greatly lower the joint loadings by the speed reduction, which eventually contribute to prevent joint injuries of wheelchair users.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.119-124
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• 2000

The 3-stage centrifugal compressor is used in order to measure the noise spectra of compressor, and analyze the results. Two cases are investigated for compressor noise components. Case I includes total system such as compressor, inter-cooler, motor, and Case II excludes cooling system. BPF tonal noise is important in compressor, and cooling system including inter-cooler contributes to broadband noise. Also, motor, gear box, and motor cooling fan are the second contributions to total compressor noise. Centrifugal compressor flow-field is calculated using two-dimensional grid and Navier-Stokes equations. Static pressure increases, and total pressure decreases, as air passes through the compressor components.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.257-263
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• 2018

The purpose of this study is to develop an automatic inspection system for a part of the differential drive gear into the transmission. This technology will make using the microvision automatic test equipment and automatic test equipment microlaser. This is that the operator intends to make the defect rate 0 in the inspection stage of the product which has been carelessly processed. The equipment developed in this research project will be applied to many areas. Packaging companies, nut bolt processing company, precisely supplier for printing on top of the semiconductor, SMT, etc. The company wants to sell the vision inspection equipment for various applications. If the defective rate of 0 is achieved through this research project, it is also possible to secure a stable supply from the parent company, and to lay the foundations for exporting based on product reliability. When the automatic inspection system is applied to domestic automobile parts processing companies, the reliability of automobiles in Korea will be greatly increased.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.159.2-159.2
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• 2011

Hyundai Heavy Industries has developed a tidal current energy converter utilizing the accumulated technology as the world largest constructor for ship and offshore structures. The model has two sets of turbines in both ends in order to utilize the bi-directional current flows in flood and ebb tide. The torque produced by turbine in tidal current is directly delivered to generator along the horizontal axis, in which the turbine, gear, generator, gear and turbine are connected successively. The manufactured model for field test has the turbine diameter of 5 meters to produce the maximum power of 500kW at maximum current speed of 5m/s. The technical verification of tidal power converter was performed by means of small scale model test in towing tank as well as field test at the Strait of Uldolmok located in Jindo of Jeollanamdo province. Field test was performed by mounting the tidal current converter on the SEP(Self Elevating Platform) which could lower the 4 vertical legs on the seabed and could elevate platform over the water surface using the hydraulic power for itself. The field test performed for a month shows that power output is similar or larger compared with the expected one in design stage. This paper presents the development of tidal current energy converter and real sea field test by Hyundai Heavy Industries. This project has finished successfully and provided the technical advance toward commercial services for tidal current power generation in the south-west region in Korea.

• Journal of the Semiconductor & Display Technology
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• v.6 no.4
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• pp.23-27
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• 2007

Rotary stages in semiconductor, display industry and many other fields require challenging accuracy to perform their functions properly. Especially, Axis of rotation error on rotary system is significant; such as the spindle error motion of the aligner, wire bonder and inspector machine which result in the poor quality products. To evaluate and improve the performance of such precision rotary stage, undesired movements on the other 5 degrees of freedom of the rotary stage must be measured and analyzed. In this paper, we have measured the three translations and two tilt motions of the worm gear type spindle with high precision capacitive sensors. To obtain the radial error motion, we have used Donaldson's reversal technique. And the axial components of the spindle tilt error motion can be obtained accurately from the axial direction outputs of sensors by Estler face motion reversal technique. Further more we have designed and developed the sensor mounting jig with standard cylinder for reversal method.

• Journal of Drive and Control
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• v.19 no.4
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• pp.36-45
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• 2022

The aim of this study was to verify an E-driving system of a 44 kW-class electric tractor using agricultural workload data. Workload data were acquired during field test (plow tillage, rotary tillage, loader operation, field driving, asphalt driving) using a conventional tractor with a load measurement system. These workload data were converted to data of a 44 kW-class tractor based on the load factor of the engine. These data were used to verify the design of the E-driving system of an electric tractor. High-load operations such as plow tillage, rotary tillage, and loader operation could be performed at stage L and stage M. High-speed operation (asphalt driving) could be effectively performed at stage H using a rated rotational speed of the motor. As a result, the E-driving system of the electric tractor was possible to perform all major agricultural operations according to gear stages of range shift. Based on results of this research, we plan to develop an electric tractor equipped with an E-driving system and conduct research on actual vehicle verification in the future.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.89-94
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• 2006

The tire delivering power generated from engine to the ground pulls a vehicle to move. Radius of tires is changeable due to elasticity that depends on the speed of vehicle and traction force. The main objectives on this study are real time measurement of dynamic radius and slip ratio according to the speed and traction force. The dynamic radius is proportional to speed and traction force. According to measurement, the dynamic radius is increased about 3mm under 100km/h compared to stop. It is also increased about 1.5mm when a traction force is supplied as much as 4kN compared to no load state at low speed. There is no strong relationship between slip ratio and vehicle speed. The slip ratio is measured up to 4% under WOT at first stage gear. Through this research, the method of measuring dynamic radius and slip ratio is set up and is expected to be applied to the measurement of traction force in chassis dynamometer or accelerating and climbing ability.

• Journal of Advanced Marine Engineering and Technology
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• v.10 no.3
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• pp.94-106
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• 1986

Since the oil shock of '70s the engine makers have developed new types of diesel engine with low fuel consumption. There is an obvious tendency towards the use of poorer quality fuels, such as the residual oil from chemical processes of refinery. The shaft driving generators is also widely adopted on behalf of the auxiliary diesel engines, which are driving on the expensive diesel oil and have high fuel oil consumption rates, and some mania propulsion diesel engines are equipped with reduction gear systems to get better propulsive efficiency by slower propeller revolutions. The propulsion shafting system equipped with the shaft driving generator or the geared diesel engine shafting system has flexible couplings, and it requires extensive investigations of the torsional vibration and torque fluctuation in order to ensure the acceptable operation range in service. The characteristics of misfiring must be especially examined for the high viscosity fuels to be used. Both torsional vibration and fluctuating torque resulted from misfiring, should be examined for thier effects on the flexible coupling and propulsion shafting system. This paper is to investigate and solve the above mentioned problems which must be predicted on the design-stage of marine propulsion shafting system. A computer program is developed to calculate the indicated diagram, fluctating torque and torsional vibration for both normal and misfiring conditions.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.1
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• pp.151-158
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• 2003

Design changes frequently occur while design activities are performed. If the impact of design changes is estimated, design efficiency can be improved. But, the types of design changes are various and they can affect other design parts. Hence, it is difficult to deal with design changes directly. The purpose of this research is to develop systematic algorithms for change propagation tracing and change impact analysis, and then to implement a change impact analysis system. We have selected a process-based design and a design environment which is composed of design parameters and constraints. The algorithm for change propagation tracing tracks the change propagation of design parameters and finds design parameters, constraints and tasks which are probably changed. In the algorithm for change impact analysis, a change impact value is calculated from the list of changeable tasks. These two algorithms have been implemented into change impact analysis system (CIAS). CIAS has been applied to the redesign of 2 stage gear drives. CIAS can improve the efficiency of design activities. If there are many alternatives for a design change at the redesign step, designers can calculate the change impact value of each alternative and perform design change activities in the direction of minimizing design change impact.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.408-414
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• 2014

After drilling operations at the offshore plant to production to crude oil to high pressure. After that time the low pressured of pipe inside when the secondary produce so oil recovery is reduced. At that time injection sea water at the pipe inside through water injection pump that the device Increase recovery so to be research and development at many industry. So developing 3-stage water injection pump at the domestic company. A variety of mathematical analysis during the detailed design analysis was not made through the dynamics characteristic. In this paper, a 2D finite element analysis is performed through the dynamics of the present study was the validation of the model.