• Progress in Superconductivity
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• v.10 no.1
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• pp.1-5
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• 2008

Magnetocardiography (MCG) is a non-contact, non-invasive, and harmless diagnostic tool to detect the abnormal electrical conductivities of the heart caused by the various coronary artery disease or cardiac muscular disease. The purpose of this study is to identify whether MCG signals and MCG parameter values vary depending on the location of sensor assembly. It will be an important reference for the standard measurement. Four healthy male subjects (33.3$\pm$6.3 years) participated in this study. Basal recording was made at 20 mm apart from the chest surface. All subjects were requested to take a regular breathe while MCG was taken. The gap between the chest surface and the bottom of the sensor assembly was 20, 40, 60, and 80 mm. Recording was made using 64 channel MCG system (Axial type, first order gradiometer) developed by Korea Research Institute of Standards and Science (KRISS). After resting for two minutes in a supine position on the bed in magnetically shielded room, MCG were recorded for 30 s. As the sensor location is getting away from the chest surface signal, the amplitude of R and T wave peak decreases to 70% (at 40 mm gap), 50% (at 60 mm), and 37% (at 80 mm) of the reference strength measured (y = $1.3903e^{-0.0169x}$, $R^2$ = 0.99; where y=amplitude remained after reduction, x=distance between chest surface and sensor location). The regression equations may be used as a good reference to calculate how much strength will be decreased by the distance. In MCG parameters, most values of parameters were decreased as the gap was increased. As an example, the current moment at T-wave peak reduced to 52% (at 40 mm gap), 33% (at 60 mm), and 19% (at 80 mm). However, the difference caused by the gap could be reduced by considering the distance when the MCG parameters were calculated. The study results can be used as a useful reference to design the baseline and the sensor location.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.3
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• pp.103-112
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• 2014

BY the Transformers and reactors, the input electrical energy is converted into magnetic energy. At the end through the magnetic energy was passed at the output parameter. Specially At the flyback transformer or a reactor airgap were designed to contain more magnetic energy. But that work is very difficult for the optimal design. It is that Contradictions are between the length of the Air-gap, Winding inductance, DC bias. As to e Several conflicting conditions in order to determine the optimum Air-gap has a lot of experience and trial & error is necessary. The approach proposed in this paper, the auxiliary winding on the core attached to part of primary core, that by applying a DC voltage has a dramatic effect like Core with designed Air-gap. This inventiveness and advantage is to regulate arbitrarily the Saturation Flux Quantity by the input signal to secondary winding. Accordingly obtained the biggest effect is that increasing limits of the saturation current destined by the material and shape of the conventional core. In other words, that can decreas the size of the transformer and reactor, While maintaining the current saturation capacity. This paper, prove its effect as using the local flux saturation in transformers and reactors for research by the computer program using the finite element method (FEM) simulation, followed by actual experiment to verify

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4C
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• pp.347-353
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• 2012

In this paper, we carried out experiments to analyze influence of vocal cords according to changes of water temperature. We would like to particularly perform a study to design voice measurement system for significant extraction about vibration patterns of vocal cords according to temperature changes of water to drink. To this end, we measured elements value of voice analysis vibration of vocal cords to change, when drank, temperature difference of step 8 from $0^{\circ}C$ to $70^{\circ}C$ to $10^{\circ}C$ intervals. As a result of us experiment, when drank water of $30^{\circ}C{\sim}40^{\circ}C$, vibration of vocal cords stabilized and accuracy of pronunciation improved. We can analyzed that water of $30^{\circ}C{\sim}40^{\circ}C$ had a good effect in vocal cords.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.155-160
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• 2007

Because output of multi-code CDMA system adapted high speed data transmission becoming multi-level system use linear amplifier in output stage and complex output signal. Therefore, Multi-Code CDMA system has shortcoming of high price, high complexity etc.. Binary CDMA technology that allow fetters in existing CDMA technology to supplement this shortcoming proposed. In binary CDMA system When correlator process high speed data, bottle-neck phenomenon is happened on synchronization acquisition process, it is very important parameter. Because existent correlator must there be advantage that power consumption is small but flow addition of several stages to receive correlation's value, the processing speed has disadvantage because the operation amount is much. Therefore in this paper, proposed correlator has characteristic such as data is able to high speed processing, chip area is independent and power consumption is constant in structure in binary CDMA system.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.177-182
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• 2008

Because output of multi-code CDMA system adapted high speed data transmission becoming multi-level system use linear amplifier in output stage and complex output signal. Therefore, Multi-Code CDMA system has shortcoming of high price, high complexity etc. Binary CDMA technology that allow fetters in existing CDMA technology to supplement this shortcoming proposed. In binary CDMA system When correlator process high speed data, bottle-neck phenomenon is happened on synchronization acquisition process, it is very important parameter. Because existent correlator must there be advantage that power consumption is small but flow addition of several stages to receive correlation's value, the processing speed has disadvantage because the operation amount is much. Therefore in this paper, proposed correlator has characteristic such as data is able to high speed processing, chip area is independent and power consumption is constant in structure in binary CDMA system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.959-962
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• 2005

Servomotors are used as key components of automated system by performing accurate positioning, accurate speed regulation, and precise motion control in response to commands from computers and sensors. Especially linear brushless servomotors have numerous advantages over ball screws, timing belts, rack/pinion drives and friction drives compared with rotary servomotors. This paper proposes the estimation of unknown parameters from the linear brushless DC motor which is operated by sinusoidal commutation. The estimated parameters are used to tune the controller gain and disturbance observer. In order to agree with this purpose, Digital Signal Processor(TMS320F240), developed for implementation of a speed Field Oriented Control(FOC), adopted in this study. The processor playing an important role in controller has A/D converters, PWM generators, riched I/O port internally.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.5
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• pp.86-94
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• 2008

In this paper proposed the solar tracking system to use a fuzzy based on PC in of order to increase an output of the PV(Photovoltaic) array. The solar tracking system operated two DC motors driving by signal of photo sensor. The control of dual axes is not an easy task due to nonlinear dynamics and unavailability of the parameters. Recently, artificial intelligent control of the fuzzy control, neural-network and genetic algorithm etc. have been studies. The fuzzy control made a nonlinear dynamics to well perform and had a robust and highly efficient characteristic about a parameter variable as well as a nonlinear characteristic. Hence the fuzzy control was used to perform the tracking system after comparing with error values of setting-up, nonlinear altitude and azimuth. In this paper designed a fuzzy controller for improving output of PV array and evaluated comparison with efficient of conventional PI controller. The data which were obtained by experiment were able to show a validity of the proposed controller.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.154-160
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• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. The limitation of this control scheme is that the feedback signal does not account for additional dynamics of the tool post and the material removal process. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surfice. However, as the accuracy requirement gets tighter and desired surface cnotours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated dapth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in additn to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamoneter. Based on the parameter estimation of cutting dynamics and the admitance model-based nanodynamic control scheme, simulation results are shown.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.879-886
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• 2008

This paper addresses the analysis and the design optimization of differential interconnects for Low-Voltage Differential Signaling (LVDS) applications. Thanks to the differential transmission and the low voltage swing, LVDS offers high data rates and improved noise immunity with significantly reduced power consumption in data communications, high-resolution display, and flat panel display. We present an improved model and new equations to reduce impedance mismatch and signal degradation in cascaded interconnects using optimization of interconnect design parameters such as trace width, trace height and trace space in differential flexible printed circuit board (FPCB) transmission lines. We have carried out frequency-domain full-wave electromagnetic simulations, time-domain transient simulations, and S-parameter simulations to evaluate the high-frequency characteristics of the differential FPCB interconnects. The 10% change in trace width produced change of approximately 6% and 5.6% in differential impedance for trace thickness of $17.5{\mu}m$ and $35{\mu}m$, respectively. The change in the trace space showed a little change. We believe that the proposed approach is very helpful to optimize high-speed differential FPCB interconnects for LVDS applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.659-666
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• 2006

Servo-motors are used as key components of automated system by performing precise motion control as accurate positioning and accurate speed regulation in response to the commands from computers and sensors. Especially, the linear brushless servo-motors have numerous advantages over the rotary servo motors which have connection with the friction induced transfer mechanism such as ball screws, timing belts, rack/pinion. This paper proposes an estimation method of unknown motor system parameters using the informations from the sinusoidal driving type linear brushless DC motor dynamics and outputs. The estimated parameters can be used to tune the controller gain and a disturbance observer. In order to meet this purpose high performance Digital Signal Processor, TMS320F240, designed originally for implementation of a Field Oriented Control(FOC) technology is adopted as a controller of the liner BLDC servo motor. Having A/D converters, PWM generators, rich I/O port internally, this servo motor application specific DSP play an important role in servo motor controller. This linear BLDC servo motor system also contains IPM(Intelligent Power Module) driver and hail sensor type current sensor module, photocoupler module for isolation of gate signals and fault signals.