• 전기학회논문지
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• 제58권5호
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• pp.923-928
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• 2009

The performance analysis and robust control of the interior permanent magnet synchronous motor(IPMSM) greatly depend on accurate value of its parameters. To achieve the high performance of torque control, it is necessary to consider exact inductance values because the inductances are nonlinear parameters of operating the IPMSM. Therefore many different methods have been performed for analysis of the methodology for the exact measurement of synchronous inductances. None of them is considered standard, and accuracy levels of all these methods are also not consistent. Among these experimental methods, the DC current decay test and the vector current control test are ideal for a laboratory environment. In this paper, these two test methods are compared by applying inductances to the IPMSM. The paper analyzes the measured inductances of the two methods and their differences with inductances obtained from the finite element method(FEM).

• 대한기계학회논문집B
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• 제21권10호
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• pp.1262-1272
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• 1997

An experimental study on the frequency control of an inverter heat pump to get the desired indoor room temperature has been conducted for the performance characteristics during the steady, 4, 8, and 16 step frequency operations. The heat pump model used in this study was operated to meet the experimental conditions of ASHRAE standard. The performance of the system was tested by measuring the temperature and pressure of the refrigerant, and cooling capacity, power consumption, etc. of the system. As the controlling frequency steps increased, the running time of the compressor increased as well as the electric consumption of the system and the cooling energy due to the wall heating load. However, the average cooling COP was improved.

• 환경영향평가
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• 제32권5호
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• pp.353-362
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• 2023

TOC는 수중에 있는 유기물질의 90% 이상을 측정할 수 있으며 신속하고 용이하게 측정할 수 있기 때문에 기존에 사용된 유기오염물질의 지표인 BOD와 COD를 대체하고 있다. 수질오염공정시험기준에 따라 TOC를 측정할 때, 시료의 총탄소 중 무기탄소 비율이 50% 이상일 경우 NPOC법으로 분석하고, 휘발성유기화합물이 수 mg/L 이상일 경우 가감(TC-IC)법으로 분석하도록 규정되어 있다. 이러한 분석조건의 제한성을 검증하기 위해 정제수에 총유기탄소와 무기성 탄소의 비율이 다르게 하여 시험용액에서 총유기 탄소 농도결과를 확인하였는데 가감법과 NPOC법에서 큰 차이가 나타나지 않았다. 휘발성유기화합물 표준 용액을 첨가한 시료를 측정한 결과, NPOC법으로 분석할 때에 퍼징으로 인해 유실되는 탄소량은 크지 않은 것으로 나타나 시료에 휘발성유기화합물이 존재 시 분석방법에 따른 차이는 크지 않은 것으로 판단된다. 수질오염공정시험기준과 환경측정기기의 형식승인·정도검사 등에 관한 고시의 기준에 의한 판정 결과가 달라지는 경우를 판단하기 위해 국내에서 널리 사용하고 있는 2종류의 총유기탄소분석기의 현장시료 농도값 차를 비교한 결과, 제조사에 따라 NPOC법과 가감법에서 0.02~0.83 mg/L 차이가 있었으며, 이에 따라 기기 선정시 주의가 필요할 것으로 판단되었다.

• 한국화재소방학회논문지
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• 제26권4호
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• pp.24-30
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• 2012

본 연구에서는 화재실과 인접부 제연구역의 차압 및 방화문의 개방력을 측정할 때의 문제점을 분석하고, 객관적인 방법에 의해 측정된 실측값을 제시하는데 있다. NFSC 501A의 제연설비 가동 시 출입문의 개방에 필요한 힘은 110 N 이하로 규정하고 있다. 제연설비가 설치된 공간에서 제연설비가 작동하지 않을 때는 KS F 2805의 시험방법에 의해서 개방력의 측정이 가능하지만 제연설비가 작동되었을 때는 화재실과 제연실의 차압에 의해 발생되는 추가적인 힘이 필요하므로 기준에서 제시하는 시험방법은 신뢰성이 부족함을 알 수 있다. 제연설비 가동 전 완전히 폐쇄된 상태의 개방력은 아날로그측정기($F_a$) 27.8 N, 디지털측정기($F_d$) 27.4 N을 각각 나타냈다. 그리고 문이 $5^{\circ}$ 개방된 상태의 개방력 $F_a$는 33 N, $F_d$는 33.6 N을 나타냈다. 제연설비가 작동되고 완전히 폐쇄된 상태의 개방력 $F_a$는 45.3 N, $F_d$는 46.9 N을 나타냈고, 문이 $5^{\circ}$ 개방된 상태의 개방력 $F_a$는 77.6 N, $F_d$는 76.0 N 등으로 확인되었다. 따라서 현재의 KS F 2805에서 제시하고 있는 기준과 상이하므로 적절한 기준의 검토가 요구된다.

• 전기학회논문지
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• 제57권12호
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• pp.2351-2357
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• 2008

Noninvasive radial artery pulse wave has been widely used not only for the pulse wave analysis(PWA) itself but also for assessment of arterial stiffness with estimated aortic pulse wave from peripheral pulse wave. However, it has been found that the deformation of pulse shape can be caused readily by changing measuring position, indentation pressure, and so on. So, in this study, we have developed a system which can measure radial pulse wave and skin displacement simultaneously while the indentation body goes down to occlude subject's radial artery. This system can be divided into a measuring apparatus part, an indentation control hardware part, a data acquisition part and a control and computation part. And, the measuring apparatus consists of an arm-rest, a step motor, an indentation body, a laser displacement sensor(LK-G30, Keyence Co.) and pulse wave sensor. Under load-free condition and radial artery loaded condition, the evaluation of developed system has been performed. From these results, we can conclude: 1) The developed system can control the indentation body quantitatively and the adopted laser displacement sensor shows linear output characteristic even with skin as a reflector. 2) This system can measure the pulse wave and the displacement of indentation body, that is, skin displacement simultaneously at each specific level of indentation body. 3) This system can provide the number of motor steps used to get down the indentation body, the measured skin displacement, the calculated indentation pressure, the calculated pulse pressure and the pulse waveform as well as the information generated by combining these with each others. 4) This system can reveal the relationship between the morphological changes of pulse wave and the estimated displacement of radial artery wall by indentation. Consequently, the developed system can furnish more abundant information on radial artery than previous diagnosis systems based on tonometric measurement. In further study, we expect to setup the standard measuring process and to concrete the algorithm for the estimation of radial artery's diameter and of displacement of radial artery's wall. Furthermore, with well designed clinical studies, we hope to turn out the usefulness of developed system in the field of cardiovascular system evaluation.

• Korea-Australia Rheology Journal
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• 제16권4호
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• pp.169-173
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• 2004

The control of the rheological properties of a fluid during processing is important and can determine the efficiency of the production in addition to the performance of the final product. The vast majority of process fluids are viscoelastic, hence an instrument that measures both the viscous and elastic properties of the material during processing would be of great practical use. However, most in-line instruments commercially available to date are only capable of measuring viscosity at a single shear rate. An in-line rheometer that measures both the viscous and elastic properties of fluids over a wide range of shear rates simultaneously has been described in a previous publication (Glasscock et at., 2003) in which the results of measurements on flowing sunflower oil were presented. Before this instrument can be used in an industrial situation, it must be demonstrated that the generated results are the same as, or bear some fixed relationship to, the results obtained by conventional off-line rheometers. To this end, the present investigation describes the measurements of a standard reference fluid, polyisobutylene dissolved in 2,6,10,14-tetramethylpentadecane, labelled SRM2490 by the National Institute of Standards and Technology (NIST) in the USA. The results obtained using the in-line rheometer show remarkably good correlation for viscosity, using a modified Cox­Merz rule, with the results supplied with the reference material from NIST.

• 화약ㆍ발파
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• 제18권2호
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• pp.14-22
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• 2000

발파소음을 계측하여 예측방법의 타당성을 검토하였고, 환경규제 기준으로의 변환방식을 규명하였다. 환산거리에 따른 발파소음의 예측은 환산거리와 음압레벨의 상관성이 더 좋았으나, 상관계수가 낮아서 환산거리 설계 의한 발파소음의 조절은 어려움이 있었다. 발파시 동시에 측정된 음압레벨과 소음레벨의 상관식에 의한 변환과, 음압레벨의 우세주파수에 해당하는 청감보정회로의 보정치만큼 간이 보정하여 변환하는 방법과, 퓨리에 변환을 하여 청감보정한 후 소음레벨을 구하는 방법을 시도하였다. 세 가지 방법 모두 변환하는 데에는 많은 오차가 발생하였으나 우세주파수, FFT를 이용한 변환보다는 발파시 동시에 측정된 음압레벨과 소음레벨의 상관식에 의한 변환 방법이 가장 실용적인 방법이었다.

• 한국산업융합학회 논문집
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• 제25권2_2호
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• pp.299-307
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• 2022

Wireless earphones, along with smart devices, are the most sought-after products by consumers. Compared to general earphones, wireless earphones do not have twisted wires and are easy to use, so various types of products are currently on the market. However, information on quality is somewhat lacking, so consumers tend to purchase products according to brand awareness, and manufacturers are delivering information to consumers using different standards for each product because there is no standard for quality control. In particular, the playback time of wireless earphones is a factor that directly affects consumers' purchases, so a standard measurement method is needed to properly measure it. In this paper, we present a method for measuring the audio playback time of wireless earphones derived from domestic wireless earphone status survey, commercial product measurement test, and research analysis, and a developed standard measurement method. In addition, this paper proposes a measurement result reporting format to provide accurate information to consumers and induce a fair competitive environment for each product to manufacturers.

• 드라이브 ㆍ 컨트롤
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• 제15권1호
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• pp.1-9
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• 2018

The spool displacement of directional control valve can be considered as the standard signal to measure the bandwidth frequency of a directional control valve. When the spool displacement is not available, the metering-orifice system is implemented in this research as an alternative way of measuring the 90 degrees phase bandwidth frequency of the hydraulic directional control valve. The inertia effect on the transmission line oil induces the phase lead of the valve load pressure when compared with the phase of spool displacement. The capacitance effect of the oil induces the phase lag of the valve load pressure. The phase of the load pressure can be adjusted to be the same as that of the spool displacement by controlling the opening area of the metering orifice. A series of experiments were conducted to verify the effectiveness of the metering orifice. The 90 degrees phase bandwidth frequency measured from the valve load pressure was significantly deviated in some cases from the frequency of the spool displacement. The metering orifice was hard to be applied to measure the -90 degrees phase bandwidth frequency of the high precision.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1647-1653
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• 2011

In the case of an urban rail chopper type subway train, varistors have been installed for protecting usual electronic equipments, semiconductor devices(diodes, transistors, thyrister, etc.) communications, measuring, control device and absorbing opening & closing surge of electromagnetic valve. These varistors were steadily reduced dielectric strength as becoming superannuated. Thus there is a problem that reacts more sensitive at the same surge in the general control operation. On existing maintenance, there is not specific standard to replace superannuated varistor. So when maintaining chopper type subway train, all varistors or old varistors that workers checked a discoloration & crack with the naked eye and noticed degradation smell by deterioration are replaced. This study suggests detail standards for judgement that varistors are good or bad chopper type subway train, and it draw a efficient maintenance which efficient maintenance can check more easy the degradation properties variation.