• Journal of Energy Engineering
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• v.10 no.4
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• pp.335-341
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• 2001

Pressure pulsations generated by the blade-tongue interaction induce vibration of the piping systems and the structure connected to pumps, resulting in the severe noise and fatigue fracture. Experiments were made on the natural frequencies of liquid columns in piping systems with a single suction, single stage, centrifugal volute pump. Experimental results show that the natural frequencies of the liquid columns in the pump piping systems depend on the dimensions of the pipes and the impeller shapes, and are not affected substantially by the rate of discharge and the rotating speed of the pump.

• Structural Engineering and Mechanics
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• v.5 no.2
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• pp.137-148
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• 1997

In computing eigenvalues for a large finite element system it has been observed that the eigenvalue extractors produce eigenvectors that are in some sense more accurate than their corresponding eigenvalues. From this observation the paper uses a patch type technique based on the eigenvector for one mesh quality to provide an eigenvalue error indicator. Tests show this indicator to be both accurate and reliable. This technique was first observed by Stephen and Steven for an error estimation for buckling and natural frequency of beams and two dimensional in-plane and out-of-plane structures. This paper produces and error indicator for the more difficult problem of three dimensional brick elements.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.139-144
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• 2008

Experimental studies using tuned liquid damper(TLD) and multiple tuned liquid damper(MTLD), which are passive control devices consisting of a rigid tank filed with liquid, are used to suppress vibration of structures. This TLD and MTLD are attributable to several potential advantage -low costs, easy; easy to install in existing structures: effective even for small amplitude vibrations. For this, we conducted shaking table experiments for two natural frequencies (0.44Hz, 0.55Hz) according to the excitation amplitude(1mm, 3mm, 5mm, 10mm, 20mm) So, the majority of studies suggested optimized natural frequence and excitation amplitude for control devices.(TLD and MTLD type : circle, rectangular) As the analysis result, we verified vibration reduction effects of a MTLD by analyzing the performance experiment of TLD and MTLD

• Journal of Power Electronics
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• v.12 no.1
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• pp.67-74
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• 2012

According to electrical output up rating of a permanent magnet motor and request to operate for a large variable speed range, resonance between structural natural vibration and electromagnetic force inside the motor can take place and make noise. This paper describes the mechanism of a resonance between them and noise lowering procedure by frequency shift when they are applied to the reluctance torque largely employed new motor named Permanent magnet Reluctance Motor (PRM).

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1961-1963
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• 1997

A new higher reaching speed algorithm for the position control systems of the treveling wave type Ultrasonic Motors(USM) is presented. As the frictional forces of the stator materials revolves the rotor, the temperature of the contact surfaces is increased. It deteriorates the performance of control system so that the control frequency of inverter deviate from the natural resonant frequence of USM during the normal operation. In order to get higher reaching speed in the position control, we propose a novel algorithm that detect the resonant frequency of USM using the simple hardware and decision Processing. The effectiveness of proposed algorithm is verified by the experimental results.

• Phonetics and Speech Sciences
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• v.3 no.4
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• pp.109-115
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• 2011

The purposes of this study were to identify acoustic parameters of connected speech and to contribute to acoustic analysis of dysphonic voice about patient's natural speech voice as well as sustained phonation of vowels. Acoustic parameters of sentences included LTAS (long-term average spectrum) mean and spectral slope over frequence ranges such as 0-4kHz, 0-6kHz, 0-8kHz, 0-12.5kHz as well as HNR. Acoustic parameters of the vowel 'a' included jitter, RAP, shimmer, NHR, and HNR. Based on 'G' of GRBAS for the severity of dysphonia, two experienced raters judged and classified as four groups including controls, mild, moderate and severe dysphonic group. Connected speech was two sentences extracted from 'stroll' passage. Parameters of the vowel and LTAS mean of the sentences were measured by CSL. The spectral slope of the sentences and HNR of the vowel and the sentences were measured by Praat. Data were statistically analyzed by Spearman correlation and Kruskal-Wallis test using SPSS 12.0. The results of this study are as follows: First, jitter, RAP, shimmer and NHR were significantly different between the groups. Second, for several frequencies, LTAS mean and spectral slope of the sentences were significantly different between the groups. Third, the HNR of the sentences were significantly different between the groups. Forth, there was a presence of correlation between HNR and NHR of the vowel and HNR of the sentences. Accordingly, this study concluded that LTAS, spectral slope, and HNR were predictive parameters of connected speech voice for dysphonic voice.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.141-147
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• 1999

Optical disk technology with a laser beam for data recording and retrieval is one of the most promising route for high density information storage in multimedia era. As the storage density and data transfer rates are increased, mechanical issues, mainly noise and vibration, become critical. Rubber materials are extensively used in various machine design application, mainly for vibration/shock/noise control devices. Over the years an enormous effort has been put into developing procedures to provide properties of rubber components with complex shape and under pre-deformed state. In this paper, non-linear large deformations of a rubber mount for optical disk drive were investigated using the finite element method. A tension test of rubber material was performed, to calculate a strain energy function. According to the pre-deformed state, the variation of rubber mount stiffness were calculated and the reliability of numerical results were checked by compared with the measuring the deflection values. Also, the effects of the pre-deformed rubber mount on the system dynamic characteristics were investigated and the relation between the static stiffness variation of rubber mount and the natural frequence variation of system was discussed.

• Journal of Life Science
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• v.17 no.10
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• pp.1441-1446
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• 2007

This study was conducted to establish the individual identification system and to estimate the genetic characteristic of Jeju native horse (JNH) using 13 microsatellite markers located on different horse autosomes. The markers were genotyped on 191 animals from five horse breeds including Jeju native horse (JNH). In total, 138 alleles were detected from the genotypes of 13 microsatellite markers. The average heterozygosities ranged from 0.317 to 0.902 and the polymorphic information content (PIC) ranged from 0.498 to 0.799 in JNH. We found that there were significant differences in allele frequencies in JNH when compared with other horse breeds. In ATH4 marker, there were specific allele frequence pattern that some of allele only found in JNH, Mongolian horse (MONG) and Jeju racing horse (JRH). The calculated cumulative power of discrimination (CPD) was 99.9% when nine microsatellite loci were used for analysis in the individual identification system. Also, the matching probability that two unrelated animals would show the same genotypes, was estimated to be $0.60{\times}10^{-10}$. Therefore, in the nine markers used in this study can be used for individual identification in the Jeju native horse population.

• The Journal of Internal Korean Medicine
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• v.18 no.1
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• pp.156-174
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• 1997

This study is investigation of clinical statistics toward to old patients of 164 persons over full 65 years old to go to hospital in 5 internal medicine department of the Dongguk University Oriental Medicine Hospital for full one year from 1995. 8 to 1996. 7. The results are followings ; 1. The ratio of male and female was 1:1.6, and in offspring figures five persons or more(60.3%) was most. A couple(32.3%) was extremely much in residing forms, but in accordance to sexual distinction in male a couple(51.7%), in female solitude(31.0%) and an eldest son couple(30.0%) was far much. 2. An attack time, first cure was most in western hospital(59.2%), 81.1% of them desired western-oriental medicine cooperation, in a medical fee charging, themselves(50.7%) were far much, and most were affirmative(76.8%) against aging prevention of restorative. 3. Main diseases were cerebral nerve(41.5%) and circulatory system(25.6%), hypertention (23.8%, 9.8%) was most in complication and the past. In defecation constipation(31.7%), in urination frequence(46.7%) was far much. 4. In preventive measures of diseases invigorant(25.6%) and nothing(24.3%) was far much and in a person tending the sick a mate in male(16.7%), a son in female(13.0%) was extremely much. 5. In sexual life most of(91.5%) didn't act, a mate death was 53.1% and female was far much. And paralysis attack was extremely much in 65-74 years old(76.5%).

• Fire Science and Engineering
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• v.29 no.6
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• pp.98-108
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• 2015

An integrated command system is critical for the safety of firefighters and effective work in the headquarters of a special disaster areas such as natural disaster or large man-made hazard. The integrated command system requires environmental information such as temperature, humidity, and $CO_2$ levels, as well as personal physical information such as pulse and air respirator levels. An Analog to Digital Converter (ADC) chip converts sensed information into digital signals, and a Micro Controller Unit (MCU) transmits the digital signals to a transmission board using serial communication through a Serial Peripheral Interface (SPI). The digital signals are saved in a transmission board and transmitted to the integrated command system by a Radio Frequency (RF) unit. The location of fire-fighters in a building are determined using a gyro sensor and an inertial sensor. The collected information is applied to the integrated command system for firefighter safety and to ensure that they can effectively carry out their duties. Tthis study theoretically and experimentally investigated the technologies of RF transmission, indoor position, and an integrated command system that supports decision making using the transmitted information.