• Physical Therapy Korea
• /
• v.22 no.3
• /
• pp.61-70
• /
• 2015

To develop an effective and efficient measurement system for tracking changes of functional status across two measures, it is essential to integrate information and communicate scores across two measures. The lack of communication between two measures leads to score incompatibility. A potential solution would be the development of a crosswalk table between those measures. Prior to creating a crosswalk table, selecting common items between two measures is critical. By using the Oswestry low back pain disability questionnaire (Oswestry) and a short form measuring disability resulting from low back pain, item level statistics as well as differential item functioning (DIF) using the Rasch measurement were investigated. Eighty-two participants with known group validity were recruited. Based on the application of the Rasch measurement model, item difficulties across the two measures were logically and hierarchically ordered. Ceiling effects for both measures were detected, which were not be able to be effectively measured with the two measures. The DIF analysis across the two measures confirmed that five paired items were found to have DIF and five common items were selected for common items. Although five paired items function differently across the Oswestry and the short form, all items of both measures were well targeted study participants. The common items selected by the Rasch measurement model may be effective when creating a crosswalk table between the Oswestry and the short form.

• Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
• /
• v.12 no.6
• /
• pp.641-654
• /
• 2018

Elevator noise in apartment houses is one of the factors which prevent the residents from quiet and comfortable life. The elevator noise measurement method [KS F ISO 16032] is introduced from the matching ISO standard, however, it has problems in the application to the actual measurement. To visualize the problems, measurements in an apartment house are conducted, which has been suffering from the elevator noise for a long time. The measurement itself is extremely difficult due to the low sound pressure level of elevator, which is lower than 35 dB (A), and the even higher background noise level. However the vibration levels measured at the same time are relatively less disturbing As a result of vibration measurement, it was found that the vibration is clearly measured on the wall, and presents a high correlation coefficient of over 0.8 with the noise levels measured This shows that the vibration level measured on the elevator walls may be rather reliable numbers than the elevator noise levels in the actual noisy condition of elevator halls and the vicinity.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.4
• /
• pp.143-147
• /
• 2018

Water levels are measured in various fields such as sewage treatment plants, water treatment plants, rivers, dams, factory storages' tanks. Ultrasonic instruments for water level measurement are expensive and are used for industrial field. Rapid advances in electronics have made it possible to build a wide variety of measurement, monitoring and control functions at low cost. This study was started to make ultrasonic level measurement system at low price. The system was constructed with an Arduino, an ultrasonic sensor and a temperature sensor for use in the experiment. The ultrasonic sensor measures the time from the sensor to the liquid surface. The temperature sensor measures the atmospheric temperature and improves the accuracy of the ultrasonic distance measurement by correcting the sound speed. Arduino controls measurements and calculates the water level. All components of the system are assembled into a device holder. Experiments with this system show that the water level measured by the system is very close to the actual value. This system is also inexpensive and easy to install and maintain, making it suitable for laboratory use.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.54 no.9
• /
• pp.403-406
• /
• 2005

Precise measurement of extremely low resistance shunt is important for characterization and calibration of high current instruments. We tested resistance measurement method for extremely high current shunt (up to 140 kA), where resistance is determined by precise measurement of voltage drop at 10 A test current in the frequency range of 40 Hz to 10 kHz. For the extremely low ac voltage to be precisely measured, a verification of the measurement method was also carried, where the inherent noise is systematically evaluated. The measurement uncertainty was estimated to be $1\;\%\;at\;95\;\%$ confidence level (k=2) for about 50 $\mu\Omega$.

• Journal of the Korean housing association
• /
• v.12 no.3
• /
• pp.125-131
• /
• 2001

The residence environment is the basis and the receptacle of daily lives and activitives. It influences on the formation of mans personality as an artificial environment. This study aims to analyze the residence environment level of the some local cities by using the Z-score method and to propose a higher residence environment. The elements of measurement in this study are determined by the general methodology. The results are as followings: 1. The residence environment level of Yeosu and Mokpo is high, that of Andong and Kyeongsan is low in this study. The ratio of road paving is the most related element in the correlation analysis. 2. The ratio of sewage supply is low compared with the scale of the dwelling area. So the sanitation environment should be improved. 3. In this correlation analysis on the residence pattern, the ratio of a single detached house is more positive than that of a multi-family house. So the single detached house pattern will be desirable in the residence environment.

• Journal of Korean Society for Atmospheric Environment
• /
• v.10 no.E
• /
• pp.299-302
• /
• 1994

At a nuclear power plant, environmental radioactivity monitoring is routine work for the radiation safety management For the environmental monitoring of tritium($^3$H) activity in water sampled liquid scintillation counting( LSC) method is applied to measure low- energy beta activity from tritium in the samples. The $^3$H activity is measured using the BECKMAN 5801 system at the KRISS( Korea Research Institute of Standards and Science) for evaluating the lower limits of detection( LLD) of $^3$H measurement and the measuring capability of low-level $^3$H activity at four nuclear Power Plant sites. The LSC systems used for low-level $^3$H activity measurements at the nuclear Power Plants are confirmed to satisfy throughout an intercomparison study under the experimental arrangements by the KRISS.

• 유체기계공업학회:학술대회논문집
• /
• 2001.11a
• /
• pp.433-438
• /
• 2001

Noise is one of the major environmental problems in human life. To reduce the noise emitted from the control valve it is necessary to develop the measurement method, measurement system, analysis method applicable to the field. In this study IEC and ISO standards were investigated and measurement method for the valve noise was proposed. Noise from the valve was measured in the reverberation room and sound power level was calculated. The sound power level increased as the flow rate and pressure difference increased. The noise characteristics are useful to predict valve noise for given conditions, to compare the performance of different valves and to develope low-noise valves.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.521-526
• /
• 2004

In order to evaluate the effect of blasting vibration in buildings and it's resident located around blasting construction field in urban area, blasting vibration characteristics were measured the vibration level, vibration velocity. The 250g and 750g of charged powder were used at the apartment and at the ground, respectively. In the measurement of the ground, Z(perpendicularity) axis was the highest value in vibration level, but vertical axis was the highest value at 25m point and longitudinal axis was the highest value at 50m point in vibration velocity. The amount of measurement was high value when measuring point is higher than blasting source, while that of measurement was low value when measuring point is lower than blasting source. In the measurement of the apartment, 2 axis was the highest value in vibration level, but in vibration velocity transverse axis was the highest value at ground, was vertical axis at 1st floor, was longitudinal axis at 3rd floor and was vertical and longitudinal axis at 5th floor. The vibration level and the vibration velocity of 50m point showed higher correlation value than 25m point at the ground, but those of 25m point showed higher correlation value than 50m point at the apartment.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.14 no.7
• /
• pp.632-638
• /
• 2004

In order to evaluate the effect of blasting vibration in buildings and it's resident located around blasting construction field in urban area, blasting vibration characteristics were measured by the vibration level, vibration velocity. The 250g and 750g of charged powder were used at the apartment and at the ground, respectively. In the measurement of the ground, 2 (perpendicularity) axis was the highest value in vibration level, but vertical direction was the highest value at 25 m point and longitudinal direction was the highest value at 50 m point in vibration velocity. The amount of measurement was high value when measuring point is higher than blasting source, while that of measurement was low value when measuring point is lower than blasting source. In the measurement of the apartment, Z axis was the highest value in vibration level, but in vibration velocity transverse direction was the highest value at ground, was vertical direction at 1st floor, was longitudinal direction at 3rd floor and was vertical and longitudinal direction at 5th floor. The vibration level and the vibration velocity of 50 m point showed higher correlation value than 25 m point at the ground, but those of 25 m point showed higher correlation value than 50 m point at the apartment.

• Transactions on Electrical and Electronic Materials
• /
• v.2 no.1
• /
• pp.16-21
• /
• 2001

A new technique to measure low level capacitance variations of a gyroscope is proposed. It is based on the improved CVC(capacitance to voltage converter) biased by a d.c. current source and the peak detector without any low pass filter. This setup of the measurement system makes it possible to provide higher speed of measurement and wide operation range. The d,c, drift of the conventional CVC and stray capacitances are automatically compensated. Key parameters that affect the performance of the measurement system are illustrated and computer simulation results are presented. The demonstrated measurement system for micromachined gyroscope applications shows a linearity of 0.99972 and a resolution of 0.67fF from 10 fF to 120 fF at 10 kHz.