• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1591-1604
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• 2023

In ocean color remote sensing, atmospheric correction is a vital process for ensuring the accuracy and reliability of ocean color products. Furthermore, in recent years, the remote sensing community has intensified its requirements for understanding errors in satellite data. Accordingly, research is currently addressing errors in remote sensing reflectance (R_rs) resulting from inaccuracies in meteorological variables (total ozone, pressure, wind field, and total precipitable water) used as auxiliary data for atmospheric correction. However, there has been no investigation into the error in R_rs caused by the variability of the water vapor profile, despite it being a recognized error source. In this study, we used the Second Simulation of a Satellite Signal Vector version 2.1 simulation to compute errors in water vapor transmittance arising from variations in the water vapor profile within the GOCI-II observation area. Subsequently, we conducted an analysis of the associated errors in ocean color products. The observed water vapor profile not only exhibited a complex shape but also showed significant variations near the surface, leading to differences of up to 0.007 compared to the US standard 62 water vapor profile used in the GOCI-II atmospheric correction. The resulting variation in water vapor transmittance led to a difference in aerosol reflectance estimation, consequently introducing errors in R_rs across all GOCI-II bands. However, the error of R_rs in the 412-555 nm due to the difference in the water vapor profile band was found to be below 2%, which is lower than the required accuracy. Also, similar errors were shown in other ocean color products such as chlorophyll-a concentration, colored dissolved organic matter, and total suspended matter concentration. The results of this study indicate that the variability in water vapor profiles has minimal impact on the accuracy of atmospheric correction and ocean color products. Therefore, improving the accuracy of the input data related to the water vapor column concentration is even more critical for enhancing the accuracy of ocean color products in terms of water vapor absorption correction.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1529-1539
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• 2023

The data from Geostationary Ocean Color Imager-II (GOCI-II), which observes the color of the sea to monitor marine environments, undergoes various correction processes in the ground station system, producing data from Raw to Level-2 (L2). Quality issues arising at each processing stage accumulate step by step, leading to an amplification of errors in the satellite data. To address this, improvements were made to the GOCI-II ground station system to measure potential optical quality and geolocation accuracy errors in the Level-1A/B (L1A/B) data. A newly established Radiometric and Geometric Performance Assessment Module (RGPAM) now measures five optical quality factors and four geolocation accuracy factors in near real-time. Testing with GOCI-II data has shown that RGPAM's functions, including data processing, display and download of measurement results, work well. The performance metrics obtained through RGPAM are expected to serve as foundational data for real-time radiometric correction model enhancements, assessment of L1 data quality consistency, and the development of reprocessing strategies to address identified issues related to the GOCI-II detector's sensitivity degradation.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.869-874
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• 2004

The inverse kinematics of five-axis milling machines produce large errors near stationary points of the required surface. When the tool travels cross or around the point the rotation angles may jump considerably leading to unexpected deviations from the prescribed trajectories. We propose three new algorithms to repair the trajectories by adjusting the rotation angles in such a way that the kinematics error is minimized. Given the tool orientations and the inverse kinematics of the machine, we first eliminate the jumping angles exceeding ${\pi}$ by using the angle adjustment algorithm, leaving the jumps less than ${\pi}$ to be further optimized. Next, we propose to apply an angle switching algorithm to compute the rotations and identify an optimized sequence of rotations by the shortest path scheme. Further error reduction is accomplished by the angle insertion algorithm based an o special interpolation to obtain the required rotations near the singularity. We have verified the algorithms by five-axis milling machines, namely, MAHO600E at the CIM Lab of Asian Institute of Technology and HERMLE UWF902H at the CIM Lab of Kasetsart University.

• Archives of Plastic Surgery
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• v.43 no.6
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• pp.604-607
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• 2016

"A smile is happiness you'll find right under your nose"- Tom Wilson. This quote holds true just for patients, not for surgeons. The correction of the nose always poses a challenge to the cosmetic surgeon. Deformities of the external and internal nose may be congenital or acquired and may be secondary to soft tissue and/or osseo-cartilaginous abnormalities, leading to aesthetic and/or functional consequences. Alar flare poses a common problem, sometimes alone and sometimes in conjunction with other external deformities. Alar base reduction is generally considered when the interalar distance exceeds the intercanthal distance. It has been well documented that this simple additional procedure brings about a substantial enhancement in the nose. Various techniques have been described and used in the past, each having their benefits and drawbacks, with the modified Weir wedge excision, Aufricht nasal sill excision, and Bernstein V-Y advancement being the common ones. We hereby describe a technique that is simple yet effective in achieving the desired results and at the same time aims at preventing relapse to obtain satisfactory long term results.

• Journal of The Korean Astronomical Society
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• v.22 no.1
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• pp.63-79
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• 1989

Current estimates, based on the same star-count analysis, of the distance to the globule Bamard 361 range from 300 pc to 650 pc. All the problems associated with the estimates have been fully rectified in this study, and a modification has been made to the classical Wolf diagram to improve the accuracy in the distance determination. A reference field was carefully selected close to the globule but well outside the globule boundary, and star counts for this field were performed on the blue POSS plate in order to set up the reference magnitude sequence appropriate to the general area of B 361. From the reference sequence, the stellar density function has been derived specifically for the direction toward the globule. Correction was made for the general interstellar extinction, and the luminosity function with the Wielen's dip was adopted. The resulting density function clearly reveals the existence of the local Cygnus-Orion arm in the direction of B 361 at about 700 pc away from the Sun. Analysis of the star-count data for the program field locates the globule at distance $600{\pm}50$ pc ; thus, the globule is an object located in the Cygnus-Orion arm, residing somewhat toward its leading edge.

• International Journal of Fluid Machinery and Systems
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• v.10 no.3
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• pp.254-263
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• 2017

The cavitation erosion remains an industrial issue for many applications. This paper deals with the cavitation intensity, which can be described as the fluid mechanical loading leading to cavitation damage. The estimation of this quantity is a challenging problem both in terms of modeling the cavitating flow and predicting the erosion due to cavitation. For this purpose, a numerical methodology was proposed to estimate cavitation intensity from 3D unsteady cavitating flow simulations. CFD calculations were carried out using Code_Saturne, which enables U-RANS equations resolution for a homogeneous fluid mixture using the Merkle's model, coupled to a $k-{\varepsilon}$ turbulence model with the Reboud's correction. A post-process cavitation intensity prediction model was developed based on pressure and void fraction derivatives. This model is applied on a flow around a hydrofoil using different physical (inlet velocities) and numerical (meshes and time steps) parameters. The article presents the cavitation intensity model as well as the comparison of this model with experimental results. The numerical predictions of cavitation damage are in good agreement with experimental results obtained by pitting test.

• The Korean Journal of Pain
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• v.19 no.2
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• pp.296-298
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• 2006

Droopy shoulder syndrome (DSS) is a rare disease, characterized by drooping shoulders, which stretches the brachial plexus, and causes pain, but without any signs of neurological impairment. These patients suffer from pain in the neck, shoulders, arms and hands, which result in long, graceful, swan necks, low-set shoulders, and horizontal or down sloping clavicles. No abnormalities in the vascular, neurological or electrical findings have also been known. The T1 and/or T2 bodies can be seen in the lateral view in a radiological study of the cervical spine. In the majority of cases, conservative treatments, such as postural correction and shoulder girdle strengthening exercise, are commonly recommended. However, DSS may be misdiagnosed as severe thoracic outlet syndrome or herniated cervical disc disease, leading to unnecessary and hazardous invasive treatments. The presented case was consistent with DSS, and was treated with stellate ganglion block, trigger point injection, and shoulder girdle strengthening exercise.

• Journal of Chest Surgery
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• v.19 no.4
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• pp.627-632
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• 1986

This report describes our 17-years experience with intracardiac repair in 123 patients older than 15 years with tetralogy of Fallot. Major clinical manifestation was cyanosis and clubbing [102 Pts], but other minor associated manifestation were infective endocarditis, pulmonary tuberculosis, brain abscess, congestive heart failure, nephrotic syndrome, and tuberculous spondylitis. Prior palliative shunts had been performed in 10 patients. Preoperative hemoglobin ranged from 9.7 gm/dl to 25 gm/dl [mean 19 gm/dl]. The type of ventricular septal defect were typical perimembranous type, and total canal defect [13%]. The right ventricular outflow tract obstruction was due to combined [58.5%], infundibular [35%], and valvular stenosis [6.5%]. Transannular patch was used in 17% of patients. Hospital mortality was 9.8% in overall, but decreased to 1.7% since 1982. There was two late death [12 year actuarial survival [97%] due to fulminant hepatitis, residual abnormalities [PS, VSD]. Ninety two percent of survivors at follow-up are asymptomatic and leading an active normal life. Residual ventricular septal defect was detected with radionuclide single pass study in 15.3% of patients but almost cases were Qp/Qs less than 1.5, and only two patients had been candidates for reoperation.

• Journal of Distribution Science
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• v.17 no.1
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• pp.11-19
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• 2019

Purpose - We document the impact of economic policy uncertainty (EPU) in the US and China on the dynamic spillover effect of macroeconomics such as stock price, housing price in Korea. Research design, data, and methodology - We use the nine variables to analyze the effect which produces a result among the EPU indexes of the US and China on economic variables which is the consumer price index (CPI), housing purchase price composite index, housing lease price, the stock price index in banking industry, construction industry and distribution industry, and composite leading indicator from January 1995 to December 2016 with the Vector Error Correction Model. Result - The US EPU index has significantly a negative relation on the CPI, housing purchase price index, housing lease price index, the stock price index in banking industry, construction industry, and distribution industry in Korea. Conclusions - We find the dynamic effect of the EPU indexes in the US and China on the macroeconomics returns in Korea. This study has an empirical evidence that the economy market in Korea is influenced by the EPU index of the US rather than it of China. The higher EPU, the more risky the economy of in Korea.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1088-1096
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• 2017

Load variations on a distribution line result in voltage fluctuations at the point of common coupling (PCC). In order to keep the magnitude of the PCC voltage constant at its rated value and obtain zero voltage regulation (ZVR), a D-STATCOM is installed for voltage correction. Moreover, the ZVR mode of a D-STATCOM can also be used to balance the source current during unbalanced loading. For medium voltage and high power applications, a D-STATCOM is realized by the cascaded H-bridge topology. In the ZVR mode, the D-STATCOM may draw unbalanced current and in this process is required to handle different phase powers leading to deviations in the cluster voltages. Zero sequence voltage needs to be injected for ZVR mode, which creates circulating power among the phases of the D-STATCOM. The computed zero sequence voltage and the individual DC capacitor balancing controller help the DC cluster voltage follow the reference voltage. The effectiveness of the control scheme is verified by modeling the system in MATLAB/SIMULINK. The obtained simulations are further validated by the experimental results using a dSPACE DS1106 and five-level D-STATCOM experimental set up.