• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.3
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• pp.116-123
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• 2003

This paper deals with an experimental study for on-line monitoring the performance of a universal motor for vacuum cleaner. Performance tests are conducted on the PC-based virtual instrumentation system designed using the graphical programming language LabVIEW. The proposed monitoring system is capable of performing real time measurement functions, including data acquisition, display, and analyses in the time and frequency domains, as well as data archiving. The measured mechanical and iron loss, voltage, current, input power, power factor, torque, and efficiency characteristics are presented as function of speed.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.5
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• pp.205-213
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• 2001

This paper presents a virtual instrumentation(VI) system for LIMs performance on-line monitoring. The VI is designed using the graphical programming language LabVIEW and is capable of performing on-line measurement functions, including data acquisition, display, and analyses in the time and frequency domains, as well as data archiving. To monitor in real time the steady-state and transient electromagnetic thrust of LIMs, the search coil is used for the determination of the flux linkage components, which is then multiplied by the appropriate current components to yield a signal proportional to the electromagnetic thrust. This paper reports the LIM's dynamics measured by the proposed on-line monitoring system.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.160-162
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• 2002

This paper presents a virtual instrumentation (VI) system for on-line monitoring the performance of universal motor. The VI is designed using the graphical programming language LabVIEW and is capable of performing real time measurement functions, including data acquisition, display, and analyses in the time and frequency domains, as well as data archiving. The electrical quantities and the mechanical quantities on the performance of universal motor monitored by the proposed system are reported.

• Smart Structures and Systems
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• v.19 no.5
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• pp.513-521
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• 2017

The purpose of this paper is to study the capabilities of the impulse response method in length and flaw detecting for concrete piles and provide a suggested method to find small-size flaws in piles. In this work, wavelet transform is used to decompose the recorded time domain signal into a series of levels. These levels are narrowband, so the mix of different dominant bandwidths can be avoided. In this study, the impulse response method is used to analyze the signal obtained from the wavelet transform to improve the judgment of the flaw signal so as to detect the flaw location. This study provides a new way of thinking in non-destructive testing detection. The results show that the length of a pile is easy to be detected in the traditional reflection time or frequency domain method. However, the small flaws within pile are difficult to be found using these methods. The proposed approach in this paper is able to greatly improve the results of small-size flaw detection within piles by reducing the effects of any noise and clarifying the signal in the frequency domains.

• Journal of Korean Clinical Nursing Research
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• v.26 no.2
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• pp.217-231
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• 2020

Purpose: To identify the clinical role of Advanced Practice Nurses (APN), and evaluate how other medical personnel perceive their work(difficulty, importance). Methods: A questionnaire survey was performed with 277 health care providers (APN 52, nurses 88, and medical doctors 137 [professors 51, fellows 44, & residents 42]) in a single, tertiary hospital. The questionnaire was categorized into 6 domains (total 40 tasks): 6 tasks on identifying health issues (A); 3 tasks on prescribing and conducting diagnostic tests (D); 18 tasks on disease treatment (T); 4 tasks regarding prescribing medicine (M); 3 tasks regarding medical collaboration (C); 6 tasks regarding patient education (E). The survey measured the frequency, difficulty, and importance of APN's clinical tasks, and evaluated the willingness of authorizing clinical tasks to APN. Results: The most frequent tasks for APN were A domain, lowest were T domain. The scores for perceived job difficulty were lower than those for job importance in all groups. The proportion of willingness to legally delegate clinical practices to APN was higher in A and E domains, but lower in D and T domains. However, professors, who spent the most time with APN, showed a higher willingness to legally delegate clinical practice. The participants favored medical doctors as substitutes for tasks which were not legislated for delegated job performance. Conclusion: In this study identified clinical roles that medical doctors considered possible for legal delegation to APN were identified. The results can be used as evidence for the legalization of the practice of APN.

• Wind and Structures
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• v.14 no.4
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• pp.337-357
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• 2011

The collection of wind speed time series by means of digital data loggers occurs in many domains, including civil engineering, environmental sciences and wind turbine technology. Since averaging intervals are often significantly larger than typical system time scales, the information lost has to be recovered in order to reconstruct the true dynamics of the system. In the present work we present a simple algorithm capable of generating a real-time wind speed time series from data logger records containing the average, maximum, and minimum values of the wind speed in a fixed interval, as well as the standard deviation. The signal is generated from a generalized random Fourier series. The spectrum can be matched to any desired theoretical or measured frequency distribution. Extreme values are specified through a postprocessing step based on the concept of constrained simulation. Applications of the algorithm to 10-min wind speed records logged at a test site at 60 m height above the ground show that the recorded 10-min values can be reproduced by the simulated time series to a high degree of accuracy.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.11
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• pp.9-16
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• 2005

This paper proposes a programmable PLL (phase locked loop) based clock generator supporting a wide-range-frequency input and output for high performance and low power SoC with multiple clock frequencies domains. The propose system reduces the locking time and obtains a wide range operation frequency by using a dual-charge pumps scheme. For low power operation of a chip, the locking processing circuits of the proposed PLL doesn't be working in the standby mode but the locking data are retained by the DAC. Also, a tracking ADC is designed for the fast relocking operation after stand-by mode exit. The programmable output frequency selection's circuit are designed for supporting a optimized DFS operation according to job tasks. The proposed PLL-based clock system has a relock time range of $0.85{\mu}sec{\sim}1.3{\mu}sec$($24\~26$cycle) with 2.3V power supply, which is fabricated on $0.35{\mu}m$ CMOS Process. At power-down mode, PLL power saves more than $95\%$ of locking mode. Also, the PLL using programmable divider has a wide locking range ($81MHz\~556MHz$) for various clock domains on a multiple IPs system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.866-872
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• 2008

Torsional oscillations of the mechanical drivetrain in electric vehicles are generated under rapid driving conditions. These lead to an uncomfortable jerking of the vehicle and to an increased stress of the mechanical components. To analyze this phenomenon, a drivetrain model is constructed with lumped parameters. The model parameters are identified by geometrical design data and experimental tests. The proposed model is validated by simulation and experimental tests in the time and the frequency domains. As a result, the torsional oscillations are observed at 7Hz of a low damped natural frequency. Also, the analysis of the effect of the parameter variations on the oscillations shows that the oscillation characteristic is mainly dependent on the rotor inertia, and the stiffness of the mounting of the drive aggregate and the driveshaft. The results will be utilized on the basis of the design of an electric drivetrain and an active control of drivetrain oscillations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.11
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• pp.1034-1042
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• 2004

In this paper, as one of countermeasure techniques for a frequency selective fading, an adaptive analog slope equalizer(ASE) applicable to 64-QAM digital radio relay system is presented in terms of principle, implementation, and its performance. Also interference of cross-talk between I- and Q-channel caused by a fiequency selective lading has been analyzed by doing channel model in the baseband, which make it possible to derive the solution for implementing ASE in If-band. The effects of signal for the faded channel are investigated in the time and the frequency domains, respectively, with/without ASE. As system performance, it is shown that the signature is improved up to 6.2 dB at the edge of signal bandwidth for a given BER 10$\^$-3/.

• The Journal of the Acoustical Society of Korea
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• v.29 no.6
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• pp.365-373
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• 2010

For effective underwater digital communications, a frame structure is used, which includes pilots in time and frequency domains for channel estimation at a receiver. To estimate channel precisely, the each pilot should be located less than coherence time and coherence bandwidth. This paper measured underwater communication environments to provide coherence time and coherence bandwidth. Based on the measurement, the paper exhibits the calculated coherence time and coherent bandwidth is adequate by computer simulations.