• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.215-228
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• 2023

The State Space Representation (SSR) method provides individual corrections for each Global Navigation Satellite System (GNSS) error components. This method can lead to less bandwidth for transmission and allows selective use of each correction. Precise Point Positioning (PPP) - Real-Time Kinematic (RTK) is one of the carrier-based precise positioning techniques using SSR correction. This technique enables high-precision positioning with a fast convergence time by providing atmospheric correction as well as satellite orbit and clock correction. Currently, the positioning service that supports PPP-RTK technology is the Quazi-Zenith Satellite System Centimeter Level Augmentation System (QZSS CLAS) in Japan. A system that provides correction for each GNSS error component, such as QZSS CLAS, requires monitoring of each error component to provide reliable correction and integrity information to the user. In this study, we conducted an analysis of the performance of residual error bounding for each error component. To assess this performance, we utilized the correction and quality indicators provided by QZSS CLAS. Performance analyses included the range domain, dispersive part, non-dispersive part, and satellite orbit/clock part. The residual root mean square (RMS) of CLAS correction for the range domain approximated 0.0369 m, and the residual RMS for both dispersive and non-dispersive components is around 0.0363 m. It has also been confirmed that the residual errors are properly bounded by the integrity parameters. However, the satellite orbit and clock part have a larger residual of about 0.6508 m, and it was confirmed that this residual was not bounded by the integrity parameters. Users who rely solely on satellite orbit and clock correction, particularly maritime users, thus should exercise caution when utilizing QZSS CLAS.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.1-8
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• 2013

In this paper, we propose a new method to correct the perspective distortion that occurs in the process of acquiring the integral images. In the proposed method, the distortion correction is based on the spectral characteristics of integral images. As element images of an integral image are repeated nearly periodically, its Fourier spectrum is given as an impulse train. On the contrary, the impulse train do not appear in the spectra of distorted images. In the proposed method, therefore, the perspective distortion parameters are detected by using the characteristics of the spectrum obtained through the Fourier transform, and then the distorted images are corrected by using the parameters. Through experiments, we verify that the proposed method effectively works for the perspective distortion correction.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.1-8
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• 2019

In this paper, we propose a correcting method of depth pixels which are failed to measure since temporary camera error. A block is modeled to plane and sphere surfaces through measured depth pixels in the block. Depth values in the block are estimated through each modeled surface and a error for the modeled surface is calculated by comparing the original and estimated pixels, then the surface which has the least error is selected. The pixels which are failed to measure are corrected by estimating depth values through selected surface. Simulation results show that the proposed method increases the correction accuracy by an average of 20% compared with the correction method of $5{\times}5$ median method.

• Journal of Drive and Control
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• v.16 no.2
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• pp.72-79
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• 2019

Despite the development of electronic components and microprocessors, hydraulic actuators are still being applied in various applications. In some applications, there is a desire to apply a hydraulic actuator with a relatively small position error to the system. Various studies have been conducted to reduce the position error of hydraulic actuators. In this paper, the position error of the hydraulic actuator when the hydraulic oil pressure is supplied is defined as the offset generated by the servo valve, and the method for correcting the servo valve offset has been studied. A method for compensating the servo valve offset was proposed and it was verified through experiments that the position error of the hydraulic actuator was reduced. We also compared the servo valve offset correction method and controller using the PID control and disturbance observer used to reduce the position error of the hydraulic actuator. No-load test and load test were performed to confirm the performance of the servo valve offset correction method. The results of the study were compared with those obtained by using the disturbance observer and PID control.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1266-1270
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• 2020

A code is developed to correct for the coincidence summing effect in detecting a voluminous gamma source, and this code is applied to a¹⁵²Eu standard source as a test case. The source is 1000 mL of liquid in a cylindrical shape. To calculate the coincidence summing effect, the cylindrical source is considered as 10(radial) × 8(height) sectional sources. For each sectional source, the peak efficiency and total efficiency are obtained by Monte Carlo simulation at each energy for 10 energies between 50 keV and 2000 keV. The efficiencies of each sector are then expressed as polynomials of gamma energy. To calculate the correction coefficients for the coincidence summing effect, the KORSUM code is used after modification. The magnitudes of correction are 4%-17% for the standard ¹⁵²Eu source measured in this study. The relative deviation of 4.7% before the coincidence correction is reduced to 0.8% after the correction is applied to the efficiency based on the measured gamma line. Hence, this study has shown that a new method has been developed that is applicable for correcting the coincidence effect in a voluminous source, and the method is applied to the measured data of a standard ¹⁵²Eu cylinder source.

• Journal of Chest Surgery
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• v.32 no.10
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• pp.930-934
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• 1999

Background: The purpose of this study is to analyze the clinical results ad operative compatability by Ravitch methods with pectus excavatum. Material and Method: From 1984 to 1997, were performed Ravitch operations in 40 patients of pectus excavatum and analyzed the effects of correction and postoperative complication according to time of operation retrospectively. The group comprised 35 mem and women whose mean age was 8.9$\pm$7.9 years(between 2 to 35 years). All patients had corrected with Ravitch operation or its modified operation. Modified fixations were accomplished with K-wire in 15 patients and internal plate in 2 and the materials were removed 3 months after operation. The result of correction was estimated with the degree of changed distance between inner surface of sternal body and vertebral in 3 months after correction. Result: Postoperative complications were wound disruption in 14 patients. Estimated distances after correction ranged 0.4 cm to 4 cm. The acceptability for chest wall correction was high(6 excellent, 29 good in criteria of Humphreys). Conclusion: We concluded that the benefits of Ravitch operation were a high acceptability of patients and their family, and sufficient correction with no specific complications related operation.

• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3488-3493
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• 2022

Accelerator driven subcritical systems have long been discussed as facilities which can be used for solving the nuclear waste problem. The physics of these systems is very different from conventional reactors and new techniques had to be developed for reactivity monitoring. One such technique is the Area Ratio Method which studies the response of a subcritical system upon insertion of a large number of neutron pulses. An issue associated with this technique is the spatial dependence of measured reactivity which is intrinsic to the sub criticality of the system since the reactor does not operate on the fundamental mode and measured reactivity depends on the detector position. This is generally addressed by defining Bell-Glasstone spatial correction factor. This factor upon multiplication with measured reactivity gives the correct reactivity which is independent of detector location. Monte Carlo Methods are used for evaluating these factors. This paper presents a complete three dimensional map of spatial correction factors for BRAHMMA subcritical system. In addition, the dataset obtained also helps in identifying detector locations where the correction factor is close to unity, thereby implying no correction if the detector is used at those locations.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.137-143
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• 2004

Erythrocyte sedimentation rate(ESR) measurements were performed in a total of 191 blood samples from patients below a hematocrit of 35% by both the Test-1(SIRE Analytical Systems, Udine, Italy) and the Westergren method, endorsed as the reference method for ESR by the International Council for Standardization in Hematology(ICSH). The corrected Westergren ESR values were also obtained applying the formula of Fabry (corrected ESR = ESR measured x 15/55-Hct). Linear regression analysis showed a close correlation (r=0.85) between the two methods both before and after ESR correction in total samples. There was no significant correlation difference between two methods in both two groups with hemoglobin $${\geq_-}9g/dl$$ and <9g/dl before and after ESR correction (r=0.873, r=0.827 respectively before correction and r=0.867, r=0.830 respectively after correction). Also, for two groups with hematocrit $${\geq_-}24%$$ and <24%, no significant difference was observed (r=0.859, r=0.792 respectively before correction and r=0.782, r=0.842 respectively after correction). However, for samples with <60mm of Westergren ESR before correction, a better correlation coefficient was obtained than samples with $${\geq_-}60mm$$(r=0.701, r=0.541 respectively). In corrected Westergren ESR, also samples that were obtained with <40mm showed better correlation than samples with $${\geq_-}40mm$$ (r=0.690, r=0.347 respectively). In conclusion, we found a good correlation between Test-1 and Westergren measurements in patients with anemia but an expert group discussion is required to solve discrepancy between two methods in blood samples with very high ESR.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.799-804
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• 1993

In this paper, the scheme of combining the orbit correction and attitude control of a 3-axis stabilized satellite is suggested. Being coupled and complimentary, it is preferable to achieve the required orbit correction and the desired attitude control simultaneously. A solution of the probes simultaneous control of orbit correction and attitude of a satellite, is obtained by solving the two point boundary value problem numerically. The first-order gradient algorithm is used to solve the numerical problem. The simulation results show that the East-West station keeping process with the combined system of an orbit correction and an attitude control is satisfactory.

• Archives of Craniofacial Surgery
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• v.12 no.1
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• pp.28-32
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• 2011

Purpose: A cranioremodeling helmet for correcting plagiocephaly was recently developed. However, no discrete objective methods to evaluate how the deformity is being corrected have been developed. We have established an easy and cost-effective method that can be used not only to show the correction process, but can also be used by physicians to assess the degree of plagiocephaly two-dimensionally. Methods: For two-dimensional evaluation, a length of malleable memory wire (2 mm in diameter) resembling "Sun-Wukong's headband" was placed on the patient's head. The wire around the patient's head was positioned on a plane including points 1 cm above the eyebrow and 1 cm above the auricle. The wire was placed on a sheet of paper and the outline was marked using pens of various colors during each visit. The degree of plagiocephaly correction could then be shown to the patient's parents at every consultation. Results: The method established by the present study easily shows the horizontal cross-section transformation of the head, illustrates plagiocephaly correction by the helmet, and shows the degree of correction in a two-dimensional manner. Conclusion: A soft-shell helmet is widely used for correcting plagiocephaly. However, evaluating the effectiveness of the helmet has been determined in a subjective manner, and a more objective method is now in demanded. Our study found that a "Sun-Wukong's headband" wire can accurately measure two-dimensional changes. Future studies will be required to identify landmarks needed for assessing plagiocephaly correction.