• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.642-651
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• 2016

For the acceleration and brake systems of an autonomous vehicle, the dynamic models from acceleration (brake) pedal input to driving(braking) torque at the vehicle wheel are represented by a set of linear transfer functions in this paper. We present an experimental method that can identify these models using a single rectangular pulse response data. Various magnitude of inputs with different running speeds are applied to experimental tests. All the identified models are demonstrated by the measured data. Both acceleration and brake models have been also validated by comparing the velocity of a full vehicle model associated with the proposed models with the measured vehicle velocity.

• Journal of the Korean Society for Railway
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• v.9 no.3 s.34
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• pp.277-281
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• 2006

The center pivot in the power car of KTX carries the traction force of the motor bogie to the carbody. The damage to the center pivot due to failure of swivel joint causes a serious hazard of the train. To prevent the hazard, information on the relative motion between bogie and carbody is necessary. In this paper, a method to measure the relative rotation of the center pivot is proposed and an actual test to verify the method and safety is conducted. The test results show that the rotation of the center pivot is within the allowable limit and the damage due to the relative motion doesn't take place.

• Journal of the Korean Institute of Navigation
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• v.21 no.3
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• pp.49-54
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• 1997

It is very important to measure and monitor hull stress which is caused by a buoyant force and a weight of cargo for safety of ship. However, an exact measurement of hul stress, using the traditional strain gage which is made of metal or semiconductor, is very difficult, because a ship would be exposed by the severe temperature environment of $-20 ^{\circ}C$ to $80 ^{\circ}C$. This paper propose a new concept strain gage which can improve accuracy and compensage effectively affects due to temperature. The strain gage is consists of two parts. One is the Hull Deformation Amplifier which introuce several lever and link system, and another is a transducer converting distance into voltage signal. The HDA measure the amount of deformation and amplify it. And a lever and link system of the HDA is introduced for compensating temperature deformation by installing in perpendicular direction without stress. This paper also reports on the results of the experiments to verify linearity of the strain gage.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.255-261
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• 2003

It is advantageous to use NDE methods to assess the mechanical properties of materials since the conventional method is time-consuming and sometimes requires cutting of sample from the component. The NDE parameters such as ultrasonic velocity and attenuation, electric resistivity, and magnetic coercive force and remanance have been utilized to evaluate changes of material properties due to heat treatment condition. It has been found that changes of materials properties under quenched and tempered/PWHT treatments could not be detected using EMAT and Electrical resistivity methods. However, victors hardness and magnetic hysteresis loop decreased with heat treatment procedures. These results were obtained using 3Cr-lMo-0.25V steel. The magnetic parameters were found to be most sensitive to changes of material properties.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.4
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• pp.159-164
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• 2003

In this paper, a three-dimensional finite element method and construction of equivalent-circuit for a linear ultrasonic motor are presented. The validity of three-dimensional finite element routine in this paper is experimentally confirmed by analyzing impedance of a piezoelectric transducer. Using this confirmed finite element routine, impedance and vibration mode of a linear ultrasonic motor are calculated. Elliptical motion of contact point between vibrator and rail of the linear ultrasonic motor is shown for determination of contact points. By using the finite element method and analytic equations, characteristics of the linear ultrasonic motor, such as thrust force, speed, losses, powers and efficiency, are calculated. The results are confirmed by experiment. Finally, equivalent circuit parameters of the linear ultrasonic motor are obtained using the three-dimensional finite element method and analytic equations.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.236-238
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• 2002

A noble fiberoptic voltage sensor system utilizing an interferometric transducer has been introduced for high voltage measurement. The sensor system employs a fiberoptic Fabry-Perot interferometric strain sensor to convert voltage to displacement in an auxiliary movable electrode. The operating mechanism is based on the fact that the electrostatic force acting on the electrode system by the applied voltage results in strain variation on the Fabry-Perot interferometry. The experiment results show that the proposed voltage sensor has the potential to be extended to very high voltage system with appropriate auxiliary electrodes.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.165-172
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• 1998

The electromechanical energy conversion conditioning and processing implementation in USM direct motion control system is generally divided into two power stages: the two-phase high-frequency ac power inversion stage for driving piezoelectric ceramic PZT transducer array off the USM stator and the mechanical thrust power conversion stage based on the frictional force between the piezo electric stator array and the rotary slider of the USM. However, the dynamic and steady-state mathematical modeling of the USM is extremely default from a theoretical point of view because it contains many complicated an nonlinear characteristics dependant on operation temperature. In +2$0^{\circ}C$~3$0^{\circ}C$, the operating characteristics of the USM has represented normal condition. But the other temperature, it has abnormal condition so that driving frequency, current and motor speed will be down. The recent USM has controller without temperature compensation. This study represents the fuzzy controller for speed compensation according to operating temperature by driving frequency.

• Fashion & Textile Research Journal
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• v.21 no.6
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• pp.697-707
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• 2019

This review paper deals with materials, classification, and a current article investigation on smart textile sensors for wearable vital signs monitoring (WVSM). Smart textile sensors can lose electrical conductivity during vital signs monitoring when applying them to clothing. Because they should have to endure severe conditions (bending, folding, and distortion) when wearing. Imparting electrical conductivity for application is a critical consideration when manufacturing smart textile sensors. Smart textile sensors fabricate by utilizing electro-conductive materials such as metals, allotrope of carbon, and intrinsically conductive polymers (ICPs). It classifies as performance level, fabric structure, intrinsic/extrinsic modification, and sensing mechanism. The classification of smart textile sensors by sensing mechanism includes pressure/force sensors, strain sensors, electrodes, optical sensors, biosensors, and temperature/humidity sensors. In the previous study, pressure/force sensors perform well despite the small capacitance changes of 1-2 pF. Strain sensors work reliably at 1 ㏀/cm or lower. Electrodes require an electrical resistance of less than 10 Ω/cm. Optical sensors using plastic optical fibers (POF) coupled with light sources need light in-coupling efficiency values that are over 40%. Biosensors can quantify by wicking rate and/or colorimetry as the reactivity between the bioreceptor and transducer. Temperature/humidity sensors require actuating triggers that show the flap opening of shape memory polymer or with a color-changing time of thermochromic pigment lower than 17 seconds.

• Journal of Sensor Science and Technology
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• v.20 no.3
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• pp.213-218
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• 2011

The load cell is a force sensor and a transducer that is used to convert a physical force into a electrical signal for weighing equipment. Most conventional load cells are widely used a metal foil strain gauge for sensing element when force being applied spring element in order to converts the deformation to electrical signals. The sensitivity of a load cell is limited by its low gauge factor, hysteresis and creep. But silicon-based sensors perform with higher reliability. This paper presents the basic design and development of the silicon type load cell with an SUS630 diaphragm. The load cell consists of two parts the silicon strain gauge and the SUS630 structure with diaphragm. Structure analysis of load cell was researched by theory to optimize the load cell diaphragm design and to determine the position of peizoresistors on a silicon strain gauge. The piezo-resistors are integrated in the four points of silicon strain gauge processed by ion implantation. The thickness of the silicon strain gauge was polished by CMP under 100 ${\mu}M$. The 10 mm diameter SUS630 diaphragm was designed for loads up to 10 kg with 300 ${\mu}M$ of diaphragm thickness. The load cell was successfully tested, the variation of ${\Delta}$R(%) of four points on the silicon strain gauge is good linearity properties and sensitivity.

• International Neurourology Journal
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• v.22 no.4
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• pp.246-251
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• 2018

Purpose: To determine whether responses to serotonin are altered in bladder strips from cats diagnosed with a naturally occurring form of bladder pain syndrome/interstitial cystitis termed feline interstitial cystitis (FIC). Methods: Full thickness bladder strips were isolated from aged matched healthy control cats and cats with clinically verified FIC. Bladder strips were mounted in an organ bath and connected to a tension transducer to record contractile activity. A serotonin dose response ($0.01-10{\mu}M$) was determined for each strip with the mucosa intact or denuded. Results: Bladder strips from control and FIC cats contracted in response to serotonin in a dose-dependent manner. The normalized force of serotonin-evoked contractions was significantly greater in bladder strips from cats with FIC (n=7) than from control cats (n=4). Removal of the mucosa significantly decreased serotonin-mediated responses in both control and FIC bladder preparations. Furthermore, the contractions in response to serotonin were abolished by $1{\mu}M$ atropine in both control and FIC bladder strips. Conclusions: The effect of serotonin on contractile force, but not sensitivity, was potentiated in bladder strips from cats with FIC, and was dependent upon the presence of the mucosa in control and FIC groups. As atropine inhibited these effects of serotonin, we hypothesize that, serotonin enhances acetylcholine release from the mucosa of FIC cat bladder strips, which could account for the increased force generated. In summary, FIC augments the responsiveness of bladder to serotonin, which may contribute to the symptoms associated with this chronic condition.