• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.561-564
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• 2004

Acoustic holography is applied to automobile aeroacoustic noise. Automobile aeroacoustic noise has low coherence due to multiple independent sources and measurement noise. This paper discusses the reliability of acoustic holography on this low coherence condition. Main subjects are the number and position of reference microphones, which is used for a step-by-step scanning method, and measurement noise. A real automobile experiment verifies the results.

• Journal of the Semiconductor & Display Technology
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• v.21 no.3
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• pp.12-16
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• 2022

In this paper, a method for measuring image pattern widths is proposed using gaussian interpolation, in order to improve inconsistent results coming from the different directions in image patterns. The performance of our method is evaluated using image patterns with 9 directions, and compared with previous methods. It is confirmed that the proposed method gives accurate and consistent width results regardless of pattern directions.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.24-28
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• 1996

In this paper, a new measurement system has been developed for measuring servo errors of CNC machine tools. Unlike the ball link bar method using circular path, the developed system uses two orthogonal straight paths for measurement of errors, giving relatively short test length. For position measurment, linear displacement sensor and steel cube have been designed, and the software for relevant data sampling and error evaluation has been implemented.

• Physical Therapy Korea
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• v.20 no.2
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• pp.20-27
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• 2013

The purpose of this study was to compare the slouched and upright sitting positions on lumbar joint reposition error (LJRE). Twenty subjects without low back pain were recruited for this study and, using a random number table, were randomly assigned to two groups; the upright sitting position group (UP group) and the slouched sitting position group (SP group). UP group was first asked to sit in an upright position and the SP group to sit in a slouched position as an intervention, and then the LJRE of both groups was measured at the neutral sitting position (lumbar flexion $0^{\circ}$). The measurement of the LJRE was repeated after one day. The sitting positions were performed for five minutes each and the LJRE was measured using an electronic goniometer. An independent t-test was used to compare the LJRE of both groups after each sitting position and after one day. The results of this study showed that the LJRE after an intervention in the UP group was lower than in the SP group (p<.05) and the LJRE after one day in the UP group was lower than in the SP group (p<.05). The findings of this study indicate that the upright sitting position can be applied to decrease LJRE, compared with the slouched sitting position. These findings also support that the upright sitting position reduces the potential for proprioceptive loss.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1848-1853
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• 2016

Control Rod Position Indicator in nuclear reactor vessel has developed for small reactor in Korea. Because of severe environment in reactor vessel, target of this study is to develop the suitable position indicator. In this study, solenoid type position indicator made of Mineral Insulated Cable(MI Cable) was introduced to adapt in severe environment. And inductance of the solenoid was used to indicate the rod position for high precision. But problem of this concept is that a linear slope of inductance is changed by temperature effect. To resolve this problem, two sensing coils were introduced for temperature compensation. A role of the sensing coil is to make reference linear equation about certain temperature. To confirm this concept, also, inductance of solenoid and sensing coils were measured at room and high temperature (${\sim}300^{\circ}C$). The results of measurement show that the position error of sensing coil between room and high temperature was about 2%. But it was identified that this error was resulted from insufficient test environment (temperature error between solenoid and sensing coils was about 2% at high temperature condition). Therefore, solenoid type position indicator shows that it is very suitable in reactor vessel as a high precision rod position indicator.

• Progress in Medical Physics
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• v.27 no.4
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• pp.213-219
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• 2016

The position verification of the radiation source utilized in brachytherapy forms a critical factor in determining the therapeutic efficiency. Currently, films are used to verify the source position; however, this method is encumbered by the lengthy time interval required from film scanning to analysis, which makes real-time position verification difficult. In general, the source position accuracy is usually tested in a monthly quality assurance check. In this context, this study investigates the feasibility of the real-time position verification of the radiation source in high dose rate (HDR) brachytherapy with the use of scintillating fibers. To this end, we construct a system consisting of scintillating fibers and a silicon photomultiplier (SiPM), optimize the dosimetric software setup and radiation system characteristics to obtain maximum measurement accuracy, and determine the relative ratio of the measured signals dependent upon the position of the scintillating fiber. According to the dosimetric results based on a treatment plan, in which the dwell time is set at 30 and 60 s at two dwell positions, the number of signals is 31.5 and 83, respectively. In other words, the signal rate roughly doubles in proportion to the dwell time. The source position can also be confirmed at the same time. With further improvements in the spatial resolution and scintillating fiber array, the source position can be verified in real-time in clinical settings with the use of a scintillating fiber-based system.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.9 no.1
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• pp.39-52
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• 2003

The test for internal and external rotation of hip joint, was donet from September 2 to 9, 2002, with the participation of 50 male/female university students who are in a normal health condition. Results are : 1. When applying the external rotation of 45 degrees angle ; 1) In a sitting position, for male it results in an increase of 5 degrees on right and left sides each. 2) In a sitting position, for female there is no change on both right and left sides. 3) In a supine position, for both male and female it results in an increase of 5 to 10 degrees on right and left sides each. 4) In a prone position, for male it results in an increase of 5 degrees on the left side only. 5) In a prone position, for female it results in an increase of 5 to 10 degrees on right and left sides each. 2. When applying the internal rotation of 45 degrees angle ; 1) In a sitting position, for male it results in a decrease of 5 degrees on right and left sides each. 2) In a sitting position, for female there is no change on both right and left sides. 3) In a supine and prone position, there is no change for male. 4) In a supine position, for female it results in an increase of 5 to 10 degrees on right and left sides each. 5) In a prone position, for female it results in an increase of 5 degrees on right and left sides each.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.219-228
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• 2013

The surveillance imaging equipments are functioning to observe the shape of the target in real time or to measure its location precisely. The roles of such equipments are becoming more important in today's weapon systems.The aforementioned imaging equipments can be classified based on the modes of operations such as fixed, installed on cars, or composite of those. Also, according to different concepts of sensor operation, a separate type uses independent housing for each sensor whereas in a composite type a set of multiple sensors are housed into a unit altogether. The sensors in general have magnetism, thereby introducing the possible negative effects, particularly in the composite types, in locating the reference position, which is carried out by the digital compass. The use of shielding material/housing could be an option but results in increased weight and reduced portability, restricting its use in composite type equipments. As such, the objective of this paper is to study on how to reduce such magnetic effects on the position location. To do so, in the absence of magnetic shielding, a variety of sensor positions were first modeled. By combing the result with the fact that the functions of PAN & Tilt are used in the equipments, a new position location algorithm is proposed. The use of the new algorithm can automate the position location process as compared to the manual process of the existing approach. In the algorithm developed, twelve locations are measured in connection with both the azimuth and elevation angles in comparison to the six locations alone around the azimuth angle. As a result, it turns out that the measurement range has been widened but the measurement time reduced. Also, note that the effect of errors the operators may make during measurement could be reduced.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.328-337
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• 2015

Objectives: The purpose of this study is to investigate differences in concentration according to the position at the left or right shoulder within a 30 cm of radius of workers' respirators and provide basic data for the establishment of an industrial health policy. Methods: Personal samples were collected from a total of 65 workers from 27 manufacturing firms in South Gyeongsang-do Province from November 5, 2011 to December 30, 2012 after classifying the laborers into left- and right-side groups. The organic compound samples were collected and analyzed in accordance with the NIOSH Manual of Analytical Methods (NMAM) 1501. Results: In terms of the concentration of organic compounds collected from both left and right shoulders at the position of workers' respirators, isobutyl acetate was the highest with 145 ppm at the left shoulder, followed by ethyl acetate (133.5 ppm) and toluene (38.13 ppm). At the right shoulder, on the contrary, ethyl acetate (149.3 ppm) was the highest, followed by toluene (46.26 ppm), xylene (29.63ppm) and isopropyl alcohol (28.06 ppm). Overall, the right shoulder was higher than the left shoulder in terms of concentrations. Conclusions: For the measurement of the working environment, workers' personal samples should be collected at the place closest to the respirator. In terms of the reduction of error, the attachment of two sample media is expected to reduce errors in exposure assessment.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.1
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• pp.33-41
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• 2015

Compact Network Real-Time Kinematic (RTK) is a method that combines compact RTK and network RTK, and it can effectively reduce the time and spatial de-correlation errors. A network RTK user receives multiple correction information generated from reference stations that constitute a network, calculates correction information that is appropriate for one's own position through a proper combination method, and uses the information for the estimation of the position. This combination method is classified depending on the method for modeling the GPS error elements included in correction information, and the user position accuracy is affected by the accuracy of this modeling. Among the GPS error elements included in correction information, tropospheric delay is generally eliminated using a tropospheric model, and a combination method is then applied. In the case of a tropospheric model, the estimation accuracy varies depending on the meteorological condition, and thus eliminating the tropospheric delay of correction information using a tropospheric model is limited to a certain extent. In this study, correction information modeling accuracy performances were compared focusing on the Low-Order Surface Model (LSM), which models the GPS error elements included in correction information using a low-order surface, and a modified LSM method that considers tropospheric delay characteristics depending on altitude. Both of the two methods model GPS error elements in relation to altitude, but the second method reflects the characteristics of actual tropospheric delay depending on altitude. In this study, the final residual errors of user measurements were compared and analyzed using the correction information generated by the various methods mentioned above. For the performance comparison and analysis, various GPS actual measurement data were collected. The results indicated that the modified LSM method that considers actual tropospheric characteristics showed improved performance in terms of user measurement residual error and position domain residual error.