• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.143-148
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• 2020

In the case of a system that detects and controls the phase of an alternating voltage, the analog control method compensates the phase offset part by filtering for the detected phase and applies it to the control. However, in the digital control method, precise control cannot be achieved due to an error between the operating frequency of the microprocessor or the microcontroller and the input phase time when controlled using such phase detection. In general, when the method used is a certain time, the accumulated error is compensated and adjusted at random. To solve this problem, a method of detecting a zero point in real time and compensating for the operating frequency of the microprocessor is needed. Therefore, the research to be performed in this paper to reduce these errors and apply them to precise digital control is as follows. 1) Research on how to implement Zero Crossing Detection algorithm through simulation modeling to compensate the zero point to match the operating frequency through detection. 2) A study on the method of detecting zero points in real time through the Zero Crossing Detection design using a microcontroller and compensating for the operating frequency of the microprocessor. 3) A study on the estimation of the rotor position of BLDC motors using the Zero Crossing Detection circuit.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.86-92
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• 2007

A discrete dynamic model for tracking feature points in 2D images is developed. Conventional snake approaches deform a contour to lock onto features of interest within an image by finding a minimum of its energy functional, composed of internal and external forces. The neighborhood around center snaxel is a space matrix, typically rectangular. The structure of the model proposed in this paper is a set of connected vertices. Energy model is designed for its local minima to comprise the set of alternative solutions available to active process. Block on tracking is one dimension, line type. Initial starting points are defined to the satisfaction of indent states, which is then automatically modified by an energy minimizing process. The track is influenced by curvature constraints, ascent/descent or upper/lower points. The advantages and effectiveness of this layer approach may also be applied to feature points tracking of digital image whose pixels have one directional properties with high autocorrelation between adjacent data lines, vertically or horizontally. The test image is the ultrasonic carotid artery image of human body, and we have verified its effect on intima/adventitia starting points tracking.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.6
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• pp.29-34
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• 2007

It is important to analyse the frequency spectrum for the measurement of modulated signal, distortion, and noise. The frequency spectrum analysis is performed by the execution of Radix-2 DIT DFT i.e. FFT algorithm. The discrete input signal converted by A/D converter from the input signal in time domain is mathematically transformed to the frequency spectrum by FFT algorithm. In this study, we design the digital spectrum analyser by the hardware based on the TMS320F2812 DSP and AD9244 converter, and by the software based on the C28x S/W modules. We can timely analyse the frequency spectrum in mobile communication system by the digital frequency analyser based on the high performance DSP and S/W modules. This real-time analysing capability is the important performance in the internet-based mobile communication server system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.7 s.337
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• pp.21-26
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• 2005

An area efficient, low power switch-matrix semidigital FIR reconstruction filter for delta-sigma D/A converter is proposed. Filter coefficients are quantified to 7-bit and 7 current sources that correspond to each coefficient bit are used. The proposed semidigital FIR reconstruction filter is designed in a 0.25 um CMOS process and incorporates 1.5 mm$^{2}$ of active area and a power consumption is 3.8 mW at 2.5 V supply. The number of switching transistors is 1419 at 205 filter order. Simulation results show that the filter output has a dynamic range of 104 dB and 84 dB attenuation of out-of-band quantization noise.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.195-200
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• 2015

This paper presents SVBS-TDC (Semi-Vernier Binary-Search Time-to-Digital Converter) for the noise improvement of ADPLL (All-Digital Phase Locked Loop. We used a Semi-Vernier BS-TDC (Binary-Search TDC) architecture to improve the operation speed more then 10 times compared with the previous conventional BS-TDC and ensured a 510ps wide input range. The proposed Semi-Vernier BS-TDC was designed in a 65ns CMOS process and the simulation results showed 200MHz speed and 4ps resolution with a 1.2V supply voltage, and considerable noise improvement of ADPLL.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.67-73
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• 2010

We have developed a millimeter-wave passive imaging system with reflector for detection of concealed objects. We have designed a millimeter-wave sensor, control device for reflector control, and a lens for focusing of millimeter-wave signal at center frequency of 94GHz. DC signal from millimeter-wave sensor output is filtered by low pass filter and amplified by video amplifier, and then converted into digital signal by using ADC/DAQ. This signal is image processed by computer, and it is possible to obtain millimeter-wave passive image with resolution of $18{\times}64$ pixel using the fabricated system. It is shown that we can obtain the image of men and concealed object with the system.

• Journal of Digital Convergence
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• v.16 no.2
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• pp.203-213
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• 2018

Purpose. This study was conducted to identify effects of the high fidelity simulation for nursing students. Methods. A non-equivalent quasi-experimental design was used to experimental group (N=43) and control group (N=39) for 8 weeks, 5 times from September 26 to November 9, 2013. Clinical performance was measured by using standardized patients. Critical thinking was measured through the questionnaire and clinical judgement was measured through observation by Lasater's rubric. Results. Clinical performance (F=211.15, p<.001), critical thinking (t=3.00, p<.004) and clinical judgement (t=7.60, p<.001) were significantly higher in experimental group with simulation education program than control group. Conclusion. Simulation education program were effective to improve clinical performance, critical thinking disposition and clinical judgement for nursing students.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.322-328
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• 2012

This paper deals with a digital Desoldering system for removing lead-free solder. We proposed a Desoldering system that is to cope with the changed work environment of the solder materials changing from lead solder to lead-free solder, we can be quickly stable to the set temperature, and continuous operation is possible. Proposed system consists of a Desoldering station and a Desoldering gun. For the PID temperature control, we designed the 8bit MCU peripheral circuit. We had a few experiments to confirm the performance of the proposed system, and compared with the specification of same kind of imports. As a result, proposed system than the imported products showed good performance as follows: the time to reach operating temperature is 11 seconds faster, ripple temperature variation is $1.5^{\circ}C$ lower, temperature recovery rate is about $0.14^{\circ}C$/sec faster.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.190-201
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• 2005

MPEG-21 has identified the need fur Event Reporting in its vision for an interoperable multimedia framework. Event Reporting is required within the MPEG-21 multimedia framework in order to provide a standardized means for sharing information about Events amongst Peers and Users. Such Events relate to Digital Items and/or Peers that interact with them. Arising from an each Event, there is the opportunity to describe what occurred. However, there are a number of difficulties in providing an accurate report about an Event. Different observers of the Event may have vastly different perspectives, needs, and focuses. They may emphasize certain elements to the detriment of others, or they may describe an Event in a way that others may find confusing. In this paper, we design how to express Event Reporting message structure and system architecture in compliance with ISO/IEC 21000-15. And we implement the system for MPEG-21 Event Reporting service.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.487-497
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• 2014

This study was to examine the effect of the Self-efficacy Promotion Exercise Program to the elderly hypertensive with Stage 1. This research was the quasi-experimental study. The Self-efficacy Promotion Exercise Program combined to Aerobic exercise which is incrementally at a level of 40~60% HRmax and the source of the Self-efficacy Promotion Exercise. This research was carried out to experimental(33 patients) and control(32 patients), 60 minutes per day, 3 times a week for 12 weeks. The Self-efficacy Promotion Program was effect on enhancing the general(p<.001) and exercise self-efficacy(p<.001), the self-care behaviors(p<.001) and decreasing the systolic blood pressure(p<.001) to the elderly hypertensives. The 12 weeks Self-efficacy Promotion Exercise Program will be considering to useful for various care settings to the elderly hypertensives.