• 열처리공학회지
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• 제9권1호
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• pp.53-61
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• 1996

Effects of carbon and Ti on damping capacity are investigated in an Fe-17%Mn alloy. The suppressive force of carbon against ${\gamma}{\rightarrow}{\varepsilon}$ transformation increases linearly with an increase in its content, lowering Ms temperature and volume fraction of ${\varepsilon}$ martensite. Carbon deteriorates damping capacity by reducing the interfacial area of damping sources and mobility of the boundaries contributing to anelastic deformation. The reduction in damping capacity is accelerated when carbon-containing alloy is aged at higher temperatures above room temperature. The effect of Ti on damping capacity is found to be benificial in carbon-containing alloy, which is attributed to the depletion of carbon solute due to the formation of TiC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.454-456
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• 1987

A more specialized area of transient evaluations is transmission line fault-detecting and protection system. During the first cycle or two following a power system fault, a high-speed protective relay is expected to make a decision as to the severity or location of the fault, usually based on 60 Hz information, i.e. the phase and magnitude of 60 Hz voltage or current signals. It is precisely at this time however that the signal is badly corrupted by noise, in the form of a de offset or frequencies above 50 Hz. One of several possible sources of transients in protection measuring signals is in the primary system for which protection is required in its response to the impact of short circuit fault on-set. Other sources are in the primary voltage and current transducers from which protection signals are derived, and, often of particular importance, in the interface circuits between the transducer secondaries and the comparator and measuring elements of the protection system. However, the noise signals that will be described in this paper are due to the main power system only and do not include errors due to current or voltage transducers.

• 경영과정보연구
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• 제6권
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• pp.89-115
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• 2001

Recently, administrators of Korean university are struggling to survive against rapidly changing environment. But, the customer service of university organizations are generally recognized inferior to those of business service. Thus, the measuring of service quality is the beginning of works to improve customer service in university. SERVQUAL is known the most generalized scale to measure service quality. After SERVQUAL was published as a measure of perceived service quality by PZB(1985), several arguments have been made against its validity and the other measures have been suggested by Tears(1993), Cronin and Taylor(1992). Therefore, this paper reviews about SERVQUAL controversies. Also, this paper analyzed the dimensions of service quality and its relevant concepts. For this empirical study, 288 respondents drawn from university student in Pusan area are collected and 5 hypotheses are analyzed by using regression analysis. The results of empirical study are as follows. (1) three dimensions of service quality(specialty, reliability, tangiables) are perceived from factor analysis. (2) dimensions of service quality are related to the overall service quality and customer satisfaction, especially specialty is varified as the most important dimension. (3) customer satisfaction affects repurchase intention and word-of-mouth effect positively. In conclusion, however this study have a few limitations about sampling and questionnaire, offers some strategic directions for improving the service quality of university organizations.

• 대한기계학회논문집B
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• 제20권1호
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• pp.384-398
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• 1996

An improved multi-channel Impedance Void Meter (IVM) is developed to measure an area-averaged void fraction. It consists of a main sensor, a reference sensor and a signal processor. The sensor was designed to be flush-mounted to the inner wall of the test section to avoid the flow disturbances. Guard electrodes are used to obtain evenly distributed electrical field in a measuring volume. A reference sensor is also installed to eliminate the drift in void signal caused by the changes in electrical properties of working fluid. The signal processor with three channels is specially designed so as to minimize the inherent error due to the phase difference between channels. As an example of applications, the mean and fluctuating components of void fraction are measured for bubbly and slug flow regime, and it is shown that IVM has good dynamic resolution which is required to investigate the structural developments of bubbly flow and the propagation of void waves in a flow channel.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.612-617
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• 2007

Water meter frost in winter is a nuisance to the water administration and citizen as well. It causes stop of water supply, possibility of accident due to leakage freezing, and additional official work to change frost water meters. This study was carried out to give some basic information of water meter frost condition, to verify the effect of frost protection devices such as lagging vinyl cover, electric heater, and meter pit using subterranean heat. Nearly half of the number of the water meter frost happens in old apartment house with outer corridor, and temperature of the meter box was measured in that kind of apartment house, comparing with atmosphere temperature. The capability of three kinds of lagging vinyl cover was investigated by measuring the inside temperature of the insulated box. Also the capability of existing meter pits and new meter pits using subterranean heat was compared by measuring the inside temperature of the pits. One of the result is that the inside temperature of meter pits using subterranean heat was higher than that of the existing ones, and deeper pit causes higher inside temperature in case of using subterranean heat.

• Physical Therapy Rehabilitation Science
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• 제2권1호
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• pp.31-38
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• 2013

Objective: To determine the efficacy and reliability of measuring direct current microcurrent applied through the skin to determine injury in the underlying tissues. Design: Case control study. Methods: First, microcurrent was measured as decreased blood flow induced hypoxia in healthy subjects. Next, reliability was assessed by measuring over ten days with set variations in pressure and distance between the electrodes. Finally, measurements over sprained ankle were compared to measurements over comparable uninjured areas on the same injured subject. Results: For the blood flow test phase, microcurrent significantly decreased an average of 17% after 5 minutes (p<0.05), remained decreased for 30 seconds, and returned to non-occlusive levels after 2 minutes of normal circulation. The results indicate that the microcurrent decrease was not due to blood flow, and most likely from hypoxic cellular damage. For the reliability phase, the coefficients of variation averaged 10.3% for the shoulder, 14.8% for the low back, and 29.1% for the knee. Changing distance 2.5 cm between the electrodes resulted in insignificant changes. Changes in pressure had some significant effect after an increase in force of 2.6 N, affirming the need for consistent pressure for measurement. For the injury test phase, a significant 69% decrease occurred comparing injured areas to the same area on the uninjured side, and a significant 74% occurred comparing injured and non-injured areas on the same limb. Conclusions: Microcurrent through the skin shows promise as an objective method of assessing a soft tissue injury by detecting damage likely due to hypoxia.

• 센서학회지
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• 제5권3호
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• pp.75-85
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• 1996

본 논문에서는 실시간으로 수질을 감시하기 위한 온라인 감시시스템을 개발하였다. 개발된 시스템은 중앙 감시 제어부, 데이타 수집기 및 단위 오염 성분 측정기들로 구성되며, 이들을 계층적인 구조로 체계적으로 결합시켜 융통성과 확장성을 가지도록하여 효율적인 데이타 수집 및 관리가 이루어지도록 하였다. 또한 수질측정의 기본이 되는 물의 염도, 전기전도도, 온도, 용존산소량 및 대장균 측정기를 원격 무인 측정이 가능하도록 설계 제작하였다.

• 한국의류학회지
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• 제6권2호
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• pp.57-67
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• 1982

The purpose of this study was to improve the clothing life of the children between the nine to twelve by making a scientific and rational basic bodice pattern. The comparison of the eight pattern drafting currently used in Korea was referred in order to make new basic pattern. Three hundred fifty-two subjects from 9 to 12 years old in Seoul area were measured on 19 items. The measurements (24 items including 19 measured items and 5 drafted items that were difficult to measure) were analyzed by mean values and correlation coefficients between each item. This new pattern attempted to set the ease for clothing from experiments of the changes of body surface in motion. On the basis of the above results, a new bodice basic pattern was developed and tested with wearing three times. Through the experiments in measuring the changes of the body surface in motion, it was concluded that it desirable to set a standard of 12cm clothing ease on the bust circumference and 4cm on the waist circumference. The correlation coefficient of the tack width to across back was relatively high (r= .677), therefore, the latter measuring items were eliminated. A grading method was adopted to determine the width and depth of neckline and shoulder slope.

• 한국안전학회지
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• 제34권4호
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• pp.15-21
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• 2019

In order to secure the safety of various machinery, it is very important to develop a technique for accurately and quickly measuring the cracks generated in the mechanical equipment and evaluating the mechanical characteristics. The evaluation of the mechanical properties is accompanied by an appropriate strain measurement according to the material and crack occurrence of the target structure. Especially, when micro cracks are generated, the evaluation method is very important. Digital image correlation is an optical full field displacement measuring method which is using currently with speckles in the interested area. However the evaluation method and conditions of image distributions have to be considered carefully to measure the crack occurrence because the images of the speckle patterns affect the quality of displacement results. In this study, the speckle pattern density is characterized to improve the accuracy of the measurement method. And also the micro crack initiation is detected by the measured displacement in the adopted speckle pattern distribution. It is shown that the proposed method is useful to determine the density pattern distribution for the accurate measurement and crack detection.

• Nuclear Engineering and Technology
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• 제34권1호
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• pp.30-41
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• 2002

The neutron beam is fully characterized for the prompt gamma activation analysis facility at Hanaro in the Korea Atomic Energy Research Institute(KAERI). The facility uses thermal neutrons which are diffracted vertically from a horizontal beam port by a set of pyrolytic graphite(PG) crystals positioned at the Bragg angle of 45" Neutron spectra, neutron flux and Cd-ratio are determined for the three extraction modes of diffracted beam by means of the theoretical and experimental efforts. To obtain theoretical result, the reflectivity of pyrolytic graphite is calculated in the diffraction model for mosaic crystal and the angular divergence after diffraction by mosaic crystal is estimated from Monte Carlo simulation. The time-of-flight spectrometer and gold activation wire are used for measuring the neutron spectra. Both the calculated and measured spectra have proven that the unique feature of polychromatic beam obtained by PG crystals are useful for PGAA. The thermal neutron flux of 7.9$\times$107 n/cm$^2$s and the Cd-ratio of 266 for gold have been achieved at the sample position while the reactor operates at 24 MW The uniformity of beam flux is 12% in the central 1$\times$1 cm$^2$ area. Finally, the beam is briefly characterized by the effective velocity and temperature which are determined by measuring the prompt Y-ray spectra for thin and thick boron samples.ples.