• Journal of Power Electronics
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• 제16권4호
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• pp.1621-1628
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• 2016

Experiencing power declines when the secondary coil is at the middle position between two primary coils is a serious problem in segmented on-road charging systems with a single energized segmented primary coil. In this paper, the topological transformation of a primary circuit and a hierarchical compensation capacitor control are proposed. Firstly, the corresponding compensation capacitors and receiving powers of different primary structures are deduced under the condition of a fixed frequency. Then the receiving power characteristics as a function of the position variations in systems with a single energized segmented primary coil and those with double segmented primary coils are analyzed comparatively. A topological transformation of the primary circuit and hierarchical compensation capacitor control are further introduced to solve the foregoing problem. Finally, an experimental prototype with the proposed topological transformation and hierarchical compensation capacitor control is carried out. Measured results show that the receiving power is a lot more stable in the movement of the secondary coil. It is a remarkable fact that the receiving power rises from 10.8W to 19.2W at the middle position between the two primary coils. The experimental are in agreement with the theoretical analysis.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.183-190
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• 2008

This paper deals with the characteristics of idle vibration due to the type of constant velocity joints. Based on the kinematics model of constant velocity joints, a offset between the tripod center and tullip center plays a important role in generating unwelcome forces. Moreover, it induced additional forces in lateral direction of a vehicle movement according to the angle of the spider in idle vibration. The difference of mass for each constant velocity joint types affect the natural frequency of the driveshaft and the powertrain. When the static torque is applied to the constant velocity joints, the natural frequencies of the driveshaft are reduced nearby 50Hz. There will be a big opportunity that the dirveshaft and constant velocity joints would be a transfer path of idle vibration at D or R gear range. Experiments indicate that TJ type is better than SFJ and DOJ in idle vibration.

• Tribology and Lubricants
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• 제36권2호
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• pp.64-67
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• 2020

In the conventional gerotor design, the circular arc tooth of the outer rotor is first introduced, and then the inner rotor profile is generated by simulating the outer rotor motion while the inner rotor is fixed. The profile generation of tooth meshing exhibits relativity; therefore, the outer rotor profile can be generated by the movement of the inner rotor. In this study, we propose the design of a gerotor with a pin-tooth inner rotor. First, the pin-tooth inner rotor is devised, and then the outer rotor profile is generated. The profile of the inner rotor is simply composed of equally arranged pins along a circle. The root of the inner rotor is designed as a conjugated arc of two pins. The trajectory of the pin center is obtained by the inner rotor operation, and then the outer rotor profile is determined as a parallel curve of the trajectory. In this gerotor design, the inner rotor has a simple configuration, and contact occurs between the pin parts of the inner rotor and the whole profile of the outer rotor. This affects the material selection and machining process. The pin tooth can be used to design the outer and inner rotors, enabling a double gerotor mechanism corresponding to a planetary gear system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.199-202
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• 2001

An elevator system, which is essential equipment for vertical movement of an object, as a property of building, has been driven by various expenditures and purposes. Since developing electrical control technology, control system are highly developed. The elevator system has expanded widely, but a data accuracy acquisition technique and safety predict technique for securing system safety is still at a basic level. So, objective verification for elevator confidence condition requires an absolute accuracy measurement technique. Therefore, this study is executed in order to acquire a method of depending on sense of a manager with simple numeric measurement data, and to construct a logical, analytical foresight system for more efficient elevator management system. As an artificial intelligence for diagnosis, the fuzzy inference algorithm is used for foreseeing the system in this thesis, because the fuzzy algorithm is the most useful method for resolving subjective ideas and a vague judgment of humans. The fuzzy inference algorithm is developed for each sensor signal(i.e. vibration, velocity, current).

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
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• pp.395-397
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• 2006

Air interlacing serves to protect the yarn against damage, strengthens inter-filament compactness or cohesion, and ensures fabric consistency. The air interlacing nozzle is used to introduce intermittent nips to a filament yarn so as to improve its performance in textile processing. The effect of various interlacing nozzle geometries on the interlacing process was studied. The geometries of interlacing nozzles with single or multiple air inlets located across the width of yarn channels are investigated. The basis case is the yarn channel, with a perpendicular main air inlet in the middle. Other cases have main air inlets, slightly inclined double sub air inlets, The yarn channel cross sectional shapes are either semicircular or rectangular shapes. The compressed impinging jet from the main air inlet hole hits the opposing bottom wall of the yarn channel, is divided into two branches, joins with the compressed air coming out from sub air inlet at the bottom and creates two free jets at both ends of the yarn channel. The compressed air movement in the cross-section consists of two opposing directional vortices. The CFD-FASTRAN flow parallel solver was used to perform steady simulations of impinging jet flow inside of the interlace nozzles. The vortical structure and the flow pattern such as pressure contour, particle traces, velocity vector plots inside of interlace nozzle geometry are discussed in this pater.

• 대한물리의학회지
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• 제15권3호
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• pp.21-27
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• 2020

PURPOSE: This study investigated the efficacy of interferential current (IFC) treatment on the improvement of pain, disability, and balance in patients with chronic nonspecific low back pain. METHODS: A double-blind randomized clinical trial was conducted with 40 patients with chronic nonspecific low back pain. The patients were randomly allocated into two groups: the IFC treatment group (n = 20) and the placebo treatment group (n = 20). The IFC group received 30 minutes of IFC treatment on the lumbar region, while the placebo group received IFC treatment without real electrical stimulation. The intervention was administered five days a week for two weeks. RESULTS: The primary outcomes of resting pain and pain during functional movement were measured by a visual analogue scale. The secondary measurements included the Oswestry disability index (ODI) for low back pain and postural sway. The measurements were performed before and after the two-week intervention period. Compared to the placebo treatment group, the IFC treatment group showed significantly greater improvement in pain during anterior trunk flexion in the standing position (p = .029), ODI (p = .039), and postural sway when subjects stood with their eyes closed (p = .010) at the end of the intervention. CONCLUSION: Our findings show that IFC treatment can improve pain, disability, and postural sway, thus, highlighting the benefits of somatosensory stimulation from IFC.

• 지역연구
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• 제10권1호
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• pp.89-104
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• 1994

Recently, environmental issues have remained high on the agendas of public discussion and economic research. In the case of Korea, democratic movement in the late 80's centered people's concerns on the environmental dispute according to landfill, correctional institution, crematory, and nuclear powerplant, etc., Moreover, the failure to provide these kinds of facilities in time have caused serious social problems associated with environmental protection and economic development. The purposes of this paper are threefolds. First, they organize foreign and domestic NIMBYS case studies which have been settled in a desirable way. The second concern is to analyze the consciousness of NIMBYS resident by making up a questionnaire. Third, they estimate the market values of urban unwanted facilities by employing CVM(Contingent Valuation Method) procedure. The results of the study have a double implication : that NIMBYS resident are reluctant to accept government mechanical compensation based on simple published land values, and that unique concensus to preserve the viability and healthfulness of our environment among three main bodies: residents, people, government is necessary in solving NIMBYS subjects in Korea. In addition, this first implication develops to emphasize the intrduction of releveant measures taken to reconcile NIMBYS disagreement, which are complete openness of government policies, full support of local economic development, and perfect management of pollution protection systems for NIMBYS facilities.

• 대한원격탐사학회지
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• 제34권1호
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• pp.17-24
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• 2018

Grounding line of a glacier or ice shelf where ice bottom meets the ocean is sensitive to changes in the polar environment. Recent rapid changes of grounding lines have been observed especially in southwestern Antarctica due to global warming. In this study, ERS-1/2 and Sentinel-1A Synthetic Aperture Radar (SAR) image were interferometrically acquired in 1996 and 2015, respectively, to monitor the movement of the grounding line in the western part of Ronne Ice Shelf near the Antarctic peninsula. Double-Differential Interferometric SAR (DDInSAR) technique was applied to remove gravitational flow signal to detect grounding line from the interferometric phase due to the vertical displacement of the tide. The result showed that ERS-1/2 grounding lines are almost consistent with those from Rignot et al. (2011) which used the similar dataset, confirming the credibility of the data processing. The comparison of ERS-1/2 and Sentinle-1A DDInSAR images showed a grounding line retreat of $1.0{\pm}0.1km$ from 1996 to 2015. It is also proved that the grounding lines based on the 2004 MODIS Mosaic of Antarctica (MOA) images and digital elevation model searching for ice plain near coastal area (Scambos et al., 2017), is not accurate enough especially where there is a ice plain with no tidal motion.

• 대한방사선기술학회지:방사선기술과학
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• 제16권2호
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• pp.19-26
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• 1993

Magnetic Resonance Image represents three-dimensional diagnostic imaging technique using both nuclear magnetic resonance phenomenon and computer. Compared with computed tomography (CT), MRI have advantages harmless to patient's body, three-dimensional image with high resolution and disadvantages long data acquisition time because of long T1 relaxation time, relatively low signal to noise ratio, high cost of setting, also. As physiologic motion of tissue results in motion ghost in MRI, high 2.0Tesla make improve low signal to noise ratio. This study have aim to improve image quality with controling motion ghost of tissue. Supposing a moving pixel in constant frequency, one pixel make two ghosts which are same size and different anti-phase. So, this study will show adjust parameter on locational control of motion ghost. Author made moving phantom replaced by respiratory movement of human, researched change of motion frequency, FOV by location shift, and them decided optimal FOV (field of view). The results are as follows: 1. The frequency content of the motion determines how far the image always appear in phase-encoding direction, the morphology of the ghost image is characteristic of the direction of the motion and its amplitude. 2. Double FOV of fixed signal object for locational control of motion ghost is recommended. Decreasement of spatial resolution by increasing FOV can compensate on increasing of matrix in spite of scan time increasement.

• 공학교육연구
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• 제22권5호
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• pp.49-55
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• 2019

Folded structure is widely applied in various engineering fields. Many of the Japanese folding fans in the Edo era (1603-1868) have been successfully blended with the processing technology of "natural materials" that is the origin of Japan's "Monodzukuri" (craftsmanship) and its application "artistic originality". The charm of a fan lies in the diversity of stereoscopic expression not born in plane representation. For example, the effects of folds, the expression of the front and back sides flowing from the front to the back by double-sided description, and the two-layer effect of raising the backside from the surface using the permeability of Japanese paper, the calculated depiction are also seen. Moreover, by handling the fan, it also produced an illusion effect which skillfully calculated the change due to movement of the viewpoint. Students experience the natural materials such as Japanese paper, bamboo and starch paste, which are the materials of paint and fan at the time, and processing method, and know the difference with the current one. This study is to verify the effectiveness of engineering education which gains experience by making concrete fans and to understand deeply this traditional technology with the artistry of a Japanese fan at the same time. And we can learn from the characteristics of the fan to Japan's history and culture.