137 results on '"COMs"'
Search Results
2. GOCI operation during the 10 years of sun interference in COMS.
- Author
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Cho, Young-Min and Choi, Woo Chang
- Subjects
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GEOSTATIONARY satellites , *OCEAN color , *METEOROLOGICAL satellites , *ARTIFICIAL satellites , *SUN , *HELIOSEISMOLOGY - Abstract
• Sun interference is studied on the 10 year-operation of Earth observation satellite. • Impact by Sun on Geostationary Ocean Color Imager (GOCI) data reception is examined. • Sun outage is prevented by GOCI imaging time adjustment in real satellite operation. • Simulation and measurement of sun interference are compared by quantitative analysis. • Prevention from sun outage in GOCI image reception is validated by operation results. A practical approach has been studied to cope with the sun interference of Earth observation geostationary satellite and the results of 10-year satellite operation for preventing sun outage are presented with detailed analysis in this paper. The Communication Ocean Meteorological Satellite (COMS) is equipped with the Geostationary Ocean Color Imager (GOCI), which performs ocean observation mission in the geostationary orbit. After the launch of the COMS, this study was initiated to prevent image data loss due to sun interference in receiving GOCI image data at the ground station of the principle user site under the operation configuration of single satellite and single ground station. This paper fully covers the entire research and the operation process which have been conducted over the 10 years from 2011 to 2021, including unexpected changes of operational environment such as ground station antenna change and satellite longitude position change. The specific characteristics of sun interference on the COMS operation is analysed through the theoretical simulation on the strength and the occurrence time of sun interference affecting the GOCI image data reception. The simulation outcomes are used to specify trigger level, date and time of sun outage in the COMS operation. From the concept that the sun outage could be prevented by adjusting the GOCI imaging time in advance, a GOCI special operation plan was established for the practical way of the sun outage prevention that was optimized for the COMS mission and could be applied to actual satellite operation. The approach of this study is verified by confirming the success of the sun outage prevention after the execution of the GOCI special operation plan. The verification is based on the operation results of the satellite link Radio Frequency (RF) signal performance and the image reception success status which has been obtained during the 10 years of the COMS operation. And, this study shows good consistency between the simulation outcomes and the operational measurements as well as the operational flexibility that it is possible to cope with the sun outage successfully even in the unexpected operational changes during the 10 years. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Swift heavy ion irradiation of thymine at cryogenic temperature.
- Author
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Mejía, C., Muniz, G.S. Vignoli, Bender, M., Severin, D., Trautmann, C., Augé, B., Agnihotri, A.N., Boduch, P., Domaracka, A., and Rothard, H.
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IRRADIATION , *THYMINE , *INFRARED absorption , *HEAVY ions , *FOURIER transform infrared spectroscopy , *ASTROPHYSICAL radiation - Abstract
Thymine (C 5 H 6 N 2 O 2) is a basic N -heterocyclic nucleobase in all known organisms, and this molecule is also found in meteoritic materials. This study aims to investigate thymine's physical and chemical modifications under ion irradiation in cryogenic conditions. Space radiation was simulated by exposing thymine at 27 K to 230 MeV 48Ca10+ ions. Fourier transform infrared spectroscopy (FTIR) was employed to monitor the degradation of a 2.8 μm thick sample film under irradiation. From the intensity decrease of the infrared absorptions as a function of ion fluence, the destruction cross-section (σ), required to dissociate or eject a thymine molecule, is deduced by an exponential function. The physical and chemical modifications induced by energetic projectiles can be related to the electronic stopping power S e as σ = S e / D 0 , where D 0 = 9.6 ± 0.4 eV/molecule is the effective mean dose needed to destroy the thymine molecule at 27 K. Also, new molecular species formed under irradiation are observed and, based on infrared spectra, identified as CN−, OCN−, HCNO, and CO. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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4. The Map Data of BRDF-Adjusted Surface Reflectance from GOCI Geostationary Satellite Imagery over Korean Peninsula
- Author
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Jong-Min Yeom
- Subjects
brdf-adjusted surface reflectance ,geostationary ocean color imager ,coms ,ndvi ,Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
In this study, the spatial maps of the BRDF (Bidirectional Reflectance Distribution Function) adjusted surface reflectance (SR) were estimated by using the Geostationary Ocean Color Imager (GOCI) mounted on the Communication, Ocean and Meteorological Satellite (COMS) over the Korean Peninsula. The BRDF-Adjusted surface Reflectance (BAR) is a more effective indicator that not only quantitatively identifies the growth characteristics of vegetation, but also corrects the bidirectional error in the time series observation characteristics, because the surface reflectance is changed according to the solar altitude during the daytime period. Therefore, this BAR products have high data utilization in various fields such as agriculture, environment, land surface information, and atmosphere. In this study, BRDF-adjusted surface reflectance maps were calculated for the Korean peninsula from April 2011 to December 2012 with hourly temporal resolution from 9 a.m. to 4 p.m. For the BAR surface reflectance, the spatial observation range is from latitude 34° N to 39 °N and longitude 125 ° E to 130 ° E, and the spatial resolution is 500 m. The semi-empirical BRDF model was used to calculate the BRDF-adjusted surface reflectance, and the radiometric characteristics of surface reflectance were decomposed into isotropic scattering, geometric scattering, and volumetric scattering. For this model simulation, at least 7 clear pixels are required to fit BRDF model. In this study, unlike the Nadir BRDF-Adjusted surface Reflectance (NBAR) calculation method which was calculated from the existing polar orbiting satellites, semi-empirical BRDF modeling was performed with a value fixed to the satellite viewing angle for each pixel since geostationary satellites of GOCI are difficult to observe in the nadir direction unlike polar satellites. It is more effective to perform BRDF correction by fixing them at the viewing angle in the case of GOCI geostationary satellite.
- Published
- 2021
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5. Concurrent optical and magnetic stimulation therapy in patients with lower extremity hard-to-heal wounds.
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Reinboldt-Jockenhöfer, Finja, Traber, Jürg, Liesch, Georg, Bittner, Christiane, Benecke, Ulf, and Dissemond, Joachim
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LEG injuries ,WOUND healing ,RESEARCH ,CHRONIC wounds & injuries ,CLINICAL trials ,PAIN ,MAGNETOTHERAPY ,COMPARATIVE studies ,QUALITY of life ,WOUND care ,LONGITUDINAL method - Abstract
Objective: The treatment of patients with hard-to-heal wounds represents a major multidisciplinary challenge. Therefore, the development and clinical validation of new technologies remains extremely important. The novel application of concurrent optical and magnetic stimulation (COMS) offers a promising noninvasive approach to support physiological wound healing processes, especially in hard-to-heal wounds. Method: In a multicentre, prospective, comparative, clinical trial, patients with hard-to-heal wounds on lower extremities of different aetiologies were treated with COMS as an adjunct to standard of care (SOC). The primary endpoint was safety; secondary endpoints were wound healing, pain and wound-specific quality of life (Wound-QoL). Results: A total of 40 patients were enrolled in this study (intention to treat population (ITTP), n=40). Of these patients, 37 were included in the analysis of the primary endpoint (primary endpoint population, (PEP), n=37). A further subgroup of 30 patients was included in the analysis of the secondary endpoint (secondary endpoint population (SEP), n=30). Finally, the SEP was stratified regarding patients' responsiveness to SOC in an SOC non-responder subgroup (NRSG), n=21, and in an SOC responder subgroup (RSG), n=9. A total of 102 adverse events (AEs) were recorded, of which 96% were 'mild' or 'moderate', and 91% were either a singular or transient event. Only 11 AEs were serious and associated with inpatient treatments unrelated to the studied intervention. In the NRSG, reductions in wound size were found to be statistically significant within the different study periods. Additionally, an acceleration of the healing rate was detected between the baseline and the first four weeks of COMS treatment (p=0.041). The rate of near-complete and complete wound closure in the SEP after 12 weeks were 60% and 43%, respectively. Pain reduction across the treatment group was statistically significant (p≤0.002 for both the SEP and NRSG). The Wound-QoL score improved by 24% during the study (p=0.001). Conclusion: In this study, COMS treatment for patients with hard-to-heal wounds on lower extremities was a safe and effective novel treatment option, especially for patients who did not respond to SOC. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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6. The Spatial Maps of Paddy Rice Yield over Northeast Asia Using COMS Geostationary Satellite and Reanalysis Meteorological Data
- Author
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Seungtaek Jeong, Jonghan Ko, and Jong-Min Yeom
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rice yield map ,coms ,spectral indices ,agriculture crop ,Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
This study estimated rice yield maps for Northeast Asia by using the Communication, Ocean and Meteorological satellite (COMS), Terra satellite, and Regional Data Assimilation and Prediction System (RDAPS) of the numerical model. The rice yield is highly useful in the study for crop information monitoring according to climate change as well as agriculture information, industry, and economy. This study produced rice yield maps for Northeast Asia including Korea, North Korea, Japan, and three northeastern provinces of China (Heilongjiang, Jilin, and Liaoning) from 2011 to 2017. The estimated spatial resolution of the rice yield maps in Northeast Asia is 500 m. The spatial observation range is 25 ° N ~ 47 ° N and 115 ° E ~ 145 ° E. In order to estimate rice yield, Remote Sensing-integrated Crop Model was employed in this study. The inputs of the RSCM are vegetation indices from Geostationary Ocean Color Imager (GOCI) of the COMS, solar radiation from Meteorological Imager of the COMS, Land Surface Water Index from the MODerate Resolution Imaging Spectroradiometer, and the temperature from the RDAPS were considered as input data. In particular, this study applied the Bidirectional Reflectance Distribution Function to the GOCI time-series images to calculate more improved vegetation indices by minimizing the directional error generated in the satellite observation location. These indices were very effective in the simulation of the rice yield.
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- 2021
- Full Text
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7. The spatial data of paddy rice classification over Northeast Asia using COMS geostationary satellite
- Author
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Seungtaek Jeong, Jonghan Ko, and Jong-Min Yeom
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paddy map ,coms ,spectral indices ,agriculture ,Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
The Korea Aerospace Research Institute (KARI) estimated paddy rice classification maps over Northeast Asia using the Cheonian geostationary orbiting satellite (COMS: Communication, Ocean and Meteorological Satellite) data. In the case of classification map of rice paddy, it is not only used as input data for estimating rice yield, but also for various fields such as agriculture, weather, climate change, bio energy, and ecology. The spatial resolution of the classified rice map is 500 m, and the classification map was estimated yearly temporal resolution from 2011 to 2017. The spatial coverage of the classification map was the Northeast Asia with the latitude 25 ° N ~ 47 ° N and the longitude 115 ° E ~ 145 ° E as shown in Fig. 1 including Heilongjiang Sheng, Jilin Sheng, and Liaoning Sheng. In this classification map of paddy rice, it was calculated by applying geostationary orbiting satellites based on value-added products from Geostationary Ocean Color Imager (GOCI). In this study, we additionally used MODIS Land Surface Water Indices (LSWI) to support rice classification by considering the physical characteristics of rice cultivation area in the transplanting season. Basically, the radiance value of the top of atmosphere (TOP) observed in GOCI satellite was corrected to the surface reflectance at the top of the canopy through radiative transfer model. After that, NDVI, which can reflect the time series growth characteristics of rice, was estimated first. In addition, the MODIS LSWI index was used to determine the rice cultivation area with the NDVI in Northeast Asia by reflecting the water characteristics of the rice cultivation area during the transplanting period. More details of validation results for this algorithm can be found in previous studies.
- Published
- 2021
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8. Intensity modulated high dose rate ocular brachytherapy using Se-75.
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Dupere, Justine M, Munro III, John J, and Medich, David C
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HIGH dose rate brachytherapy , *LOW dose rate brachytherapy , *GOLD rings , *OPTIC nerve - Abstract
We propose an alternative to LDR brachytherapy for the treatment of ocular melanomas by coupling intensity modulation, through the use of a gold shielded ring applicator, with a middle energy HDR brachytherapy source, Se-75. In this study, we computationally test this proposed design using MCNP6. An array of discrete Se-75 sources is formed into a ring configuration within a gold shielded applicator, which collimates the beam to a conical shape. Varying this angle of collimation allows for the prescription dose to be delivered to the apex of various sized targets. Simulations in MCNP6 were performed to calculate the dosimetric output of the Se-75 ring source for various sized applicators, collimators, and target sizes. The prescription dose was delivered to a range of target apex depths 3.5−8 mm in the eye covering targets 10-15 mm in diameter by using various sized applicators and collimators. For a 16 mm applicator with a collimator opening that delivers the prescription dose to a depth of 5 mm in the eye, the maximum percent dose rate to critical structures was 30.5% to the cornea, 35.7% to the posterior lens, 33.3% to the iris, 20.1% to the optic nerve, 278.0% to the sclera, and 267.3% to the tumor. When using Se-75 in combination with the proposed gold shielded ring applicator, dose distributions are appropriate for ocular brachytherapy. The use of a collimator allows for the dose to more easily conform to the tumor volume. This method also reduces treatment time and cost, and it eliminates hand dose to the surgeon through the use of a remote afterloader device. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
9. How to design, fabricate, and validate a customized COMS-style eye plaque: Illustrated with a narrow-slotted plaque example.
- Author
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Deufel, Christopher L., Dalvin, Lauren A., Qian, Jing, Vaishnav, Birjoo, Cutsinger, Jordan McCauley, Wittich, Michelle Neben, and Petersen, Ivy A.
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OCULAR tumors , *PHYSICAL measurements , *RADIATION dosimetry , *ULTRASONIC imaging , *MAGNETIC resonance - Abstract
A customized Collaborative Ocular Melanoma Study (COMS)-style eye plaque may provide superior dosimetric coverage compared with standard models for certain intraocular tumor locations and shapes. This work provides a recipe for developing and validating such customized plaques. The concept-into-clinical treatment process for a customized COMS-style eye plaque begins with a CAD model design that meets the specifications of the radiation oncologist and surgeon based on magnetic resonance, ultrasound, and clinical measurements, as well as a TG-43 hybrid heterogeneity-corrected dose prediction to model the dose distribution. Next, a 3D printed plastic prototype is created and reviewed. After design approval, a Modulay plaque is commercially fabricated. Quality assurance (QA) is subsequently performed to verify the physical measurements of the Modulay and Silastic and also includes dosimetric measurement of the calibration, depth dose, and dose profiles. Sterilization instructions are provided by the commercial fabricator. This customization procedure and QA methodology is demonstrated with a narrow-slotted plaque that was recently constructed for the treatment of a circumpapillary (e.g., surrounding the optic disk) ocular tumor. The production of a customized COMS-style eye plaque is a multistep process. Dosimetric modeling is recommended to ensure that the design will meet the patient's needs, and QA is essential to confirm that the plaque has the proper dimensions and dose distribution. The customized narrow-slotted plaque presented herein was successfully implemented in the clinic, and provided superior dose coverage of juxtapapillary and circumpapillary tumors compared with standard or notched COMS-style plaques. Plaque development required approximately 30 h of physicist time and a fabrication cost of $1500. Customized eye plaques may be used to treat intraocular tumors that cannot be adequately managed with standard models. The procedure by which a customized COMS-style plaque may be designed, fabricated, and validated was presented along with a clinical example. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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10. Design and optimizing a novel ocular plaque brachytherapy with dual-core of 103Pd and 106Ru.
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Sharifzadeh, Mohsen, Chiniforoush, Tayebeh A., and Sadeghi, Mahdi
- Abstract
• New ocular plaque brachytherapy by combining COMS and BEBIG plaques. • Dual-core plque activated by IRA1-
103 Pd and106 Ru plate. • Dose increasement of ocular tumor relative to COMS and BEBIG plaques separately. • Reduction of exposure time for ocular beachytherapy. In recent decades, eye plaques of brachytherapy have been extensively used as primary treatment as well as a complementary treatment for ocular cancer. The purpose of this study is the development of the eye plaque brachytherapy throughout a new design of eye plaque by combining the COMS plaque and the CCB BEBIG plaque loaded by IRA1-103 Pd and106 Ru, respectively. A new dual-core plaque with a diameter of 20 mm was designed in the way that the BEBIG plaque with a diameter of 20 mm loaded by106 Ru plate is attached to the COMS plaque with a diameter of 20 mm loaded by 24 of IRA1-103 Pd seeds. Dose calculations for the new plaque were performed by using the MCNP5 code. Dose calculations of dual-core plaque including103 Pd seeds (gamma) and106 Ru plate (beta) were separately done for the sake of MCNP constraints in gamma and beta particle transfer simultaneously. The new dual-core plaque delivers a much higher dose rate to the tumor compared with every single plaque, while the dose rate reached to healthy tissues is slightly higher than each plaque separately. Of course, this is acceptable because the treatment time reduces and subsequently the error in radiation therapy reduces. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
11. A Monte Carlo dose calculation system for ophthalmic brachytherapy based on a realistic eye model.
- Author
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Miras del Río, Héctor, Ortiz Lora, Antonio, Bertolet Reina, Alejandro, and Terrón León, José Antonio
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RADIOISOTOPE brachytherapy , *SCLERA , *COMPUTING platforms , *ALGORITHMS , *RADIOTHERAPY , *CLOUD computing , *IMAGING phantoms - Abstract
Purpose: There is a growing trend towards the adoption of model‐based calculation algorithms (MBDCAs) for brachytherapy dose calculations which can properly handle media and source/applicator heterogeneities. However, most of dose calculations in ocular plaque therapy are based on homogeneous water media and standard in‐silico ocular phantoms, ignoring non‐water equivalency of the anatomic tissues and heterogeneities in applicators and patient anatomy. In this work, we introduce EyeMC, a Monte Carlo (MC) model‐based calculation algorithm for ophthalmic plaque brachytherapy using realistic and adaptable patient‐specific eye geometries and materials. Methods: We used the MC code PENELOPE in EyeMC to model Bebig IsoSeed I25.S16 seeds in COMS plaques and 106Ru/106Rh applicators that are coupled onto a customizable eye model with realistic geometry and composition. To significantly reduce calculation times, we integrated EyeMC with CloudMC, a cloud computing platform for radiation therapy calculations. EyeMC is equipped with an evaluation module that allows the generation of isodose distributions, dose–volume histograms, and comparisons with Plaque Simulator three‐dimensional dose distribution. We selected a sample of patients treated with 125I and 106Ru isotopes in our institution, covering a variety of different type of plaques, tumor sizes, and locations. Results from EyeMC were compared to the original plan calculated by the TPS Plaque Simulation, studying the influence of heterogeneous media composition as well. Results: EyeMC calculations for Ru plaques agreed well with manufacturer's reference data and data of MC simulations from Hermida et al. (2013). Significant deviations, up to 20%, were only found in lateral profiles for notched plaques. As expected, media composition significantly affected estimated doses to different eye structures, especially in the 125I cases evaluated. Dose to sclera and lens were found to be about 12% lower when considering real media, while average dose to tumor was 9% higher. 106Ru cases presented a 1%–3% dose reduction in all structures using real media for calculation, except for the lens, which showed an average dose 7.6% lower than water‐based calculations. Comparisons with Plaque Simulator calculations showed large differences in dose to critical structures for 106Ru notched plaques. 125I cases presented significant and systematic dose deviations when using the default calculation parameters from Plaque Simulator version 5.3.8., which were corrected when using calculation parameters from a custom physics model for carrier‐attenuation and air‐interface correction functions. Conclusions: EyeMC is a MC calculation system for ophthalmic brachytherapy based on a realistic and customizable eye‐tumor model which includes the main eye structures with their real composition. Integrating this tool into a cloud computing environment allows to perform high‐precision MC calculations of ocular plaque treatments in short times. The observed variability in eye anatomy among the selected cases justifies the use of patient‐specific models. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
12. EyeDose: An open-source tool for using published Monte Carlo results to estimate the radiation dose delivered to the tumor and critical ocular structures for 125I Collaborative Ocular Melanoma Study eye plaques.
- Author
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Deufel, Christopher L., McCauley Cutsinger, Sarah, Corbin, Kimberly S., Dalvin, Lauren A., and Petersen, Ivy A.
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MONTE Carlo method , *UVEA cancer , *OCULAR tumors , *RADIATION doses , *COMPUTED tomography , *LACRIMAL apparatus , *OPTIC disc - Abstract
Radiation side effects and visual outcome for uveal melanoma patients managed with plaque radiotherapy are dependent on the radiation dose administered to the tumor and nearby healthy tissues. We have developed an open-source software tool, EyeDose, to simplify and standardize tumor and critical structure dose reporting for Collaborative Ocular Melanoma Study eye plaques. EyeDose is a MATLAB-based program that calculates point dose and volume dose metrics for standard models of the tumor and critical ocular structures. It uses published three-dimensional dose distributions for eye plaques, calculated with Monte Carlo methods, which are oriented with respect to the eye using the tumor's position on a fundus diagram. A standard model for the ocular structures was created using published measurements and patient CT scans. EyeDose reports radiation statistics for the fovea, optic disc, lens, lacrimal gland, retina, and tumor. The dosimetric margin for implant placement uncertainty is also calculated. EyeDose calculations were validated against previously published Monte Carlo results for eight different tumor positions, including the dose to the fovea, optic disc, lacrimal gland, lens, and along the central axis. EyeDose accepts a spreadsheet input for rapidly processing large retrospective patient data sets, with an average run time of <40 s per patient. EyeDose is published as an open-source tool for easy adaptation at different institutions. EyeDose calculates radiation statistics for Collaborative Ocular Melanoma Study eye plaque patients with Monte Carlo accuracy and without a treatment planning system. EyeDose streamlines data collection for large retrospective studies and can also be used prospectively to assess plaque applicability. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
13. Mortality after deferral of treatment or no treatment for choroidal melanoma
- Author
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Bradley R Straatsma, Marie Diener-West, Robert Caldwell, Robert E Engstrom, and For The Collaborative Ocular Melanoma Study Group
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Choroidal melanoma ,COMS ,melanoma ,mortality ,uveal melanoma ,Ophthalmology ,RE1-994 - Abstract
Purpose: To report mortality of patients who were eligible for enrollment in the Collaborative Ocular Melanoma Study (COMS) clinical trials of medium-sized choroidal melanoma or large-sized choroidal melanoma but chose to defer treatment or receive no melanoma treatment. Design: Prospective nonrandomized multicenter cohort study as an adjunct to COMS randomized clinical trials. Methods: Patient follow-up procedures included examinations, correspondence, telephone contacts, and National Death Index searches. Primary outcome was patient death measured by all-cause mortality. Secondary outcomes were melanoma treatment and melanoma metastasis. Results: Of 77 patients eligible for COMS clinical trials who chose to defer or receive no melanoma treatment, 61 were appropriate candidates and 45 (74%) enrolled in the natural history study (NHS). In all, 42 patients (42 eyes) had medium melanoma, and the median follow-up was 5.3 years (range, 4–10.7 years). In all, 22 patients (52%) had subsequent melanoma treatment, and 20 (48%) had no melanoma treatment. For the 42 patients, Kaplan–Meier estimate of 5-year mortality was approximately 30% [95% confidence interval (CI), 18%–47%]. For COMS medium melanoma trial, 5-year mortality was 18% (95% CI, 16%–20%), not statistically significantly different from the NHS patients. After adjusting for differences in age and longest basal diameter, the 5-year risk of death for NHS patients versus COMS trial patients was 1.54 (95% CI, 0.93–2.56). Three patients had large melanoma. Melanoma metastasis was confirmed or suspected in 8 (42%) of 19 deaths. Conclusion: Greater mortality and higher risk of death for NHS patients are probative but not conclusive evidence of a beneficial, life-extending effect of medium melanoma treatment.
- Published
- 2018
- Full Text
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14. Experimental validation of a new COMS-like 24 mm eye plaque for the treatment of large ocular melanoma tumors.
- Author
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McCauley Cutsinger, Sarah, Forsman, Renae, Corner, Stephen, and Deufel, Christopher L.
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PHYSICAL measurements , *VERNIERS , *EYE , *SCLERA , *UVEA cancer , *OCULAR tumors - Abstract
A new Collaborative Ocular Melanoma Study (COMS)-like 24 mm eye plaque was experimentally characterized using physical and dosimetric measurements in preparation for clinical usage. The new eye plaque will enable surgeons and radiation oncologists to accommodate patients who have larger ocular melanoma tumors. Physical measurement of the Modulay radius of curvature was performed using a FARO Edge, and the base thickness of the Silastic insert was measured with a depth gauge and Vernier caliper. Dosimetric measurements, using Gafchromic film, were used to determine the absolute dose as a function of the depth along the plaque's central axis, profiles as a function of polar angle, and basal coverage at the inner sclera. The measured results were compared with a theoretical model, which incorporated the plaque's heterogeneities using a modified TG-43 formalism. The Modulay radius of curvature measured 14.7 mm (specification = 14.55 mm). The Silastic base thickness measured 0.9 mm (specification = 1.0 mm). For a 24 mm plaque fully loaded with 1.27 U 125I model 2301 seeds, the dose rate at a prescription depth of 5 mm from the inner sclera was measured to be 36 cGy U−1 hr−1. The basal coverage for the same prescription depth was 17.9 mm. The experimental measurements were in close agreement with the theoretical predictions. The new 24 mm COMS-like plaque was experimentally validated for clinical use. Physical and dosimetric measurements for the 24 mm plaque agreed with nominal specifications and theoretical predictions. The 24 mm plaque provides greater basal coverage and lower surface doses than existing COMS plaques. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
15. Conserved Pheromone Production, Response and Degradation by Streptococcus mutans.
- Author
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Ricomini Filho, Antonio Pedro, Khan, Rabia, Åmdal, Heidi Aarø, and Petersen, Fernanda C.
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STREPTOCOCCUS mutans ,PHEROMONES ,LUCIFERASES ,REPORTER genes ,BIOLOGICAL assay - Abstract
Streptococcus mutans , a bacterium with high cariogenic potential, coordinates competence for natural transformation and bacteriocin production via the XIP and CSP pheromones. CSP is effective in inducing bacteriocin responses but not competence in chemically defined media (CDM). This is in contrast to XIP, which is a strong inducer of competence in CDM but can also stimulate bacteriocin genes as a late response. Interconnections between the pathways activated by the two pheromones have been characterized in certain detail in S. mutans UA159, but it is mostly unknown whether such findings are representative for the species. In this study, we used bioassays based on luciferase reporters for the bacteriocin gene cipB and the alternative sigma factor sigX to investigate various S. mutans isolates for production and response to CSP and XIP pheromones in CDM. Similar to S. mutans UA159, endogenous CSP was undetectable in the culture supernatants of all tested strains. During optimization of the bioassay using the cipB reporter, we discovered that the activity of exogenous CSP used as a standard was reduced over time during S. mutans growth. Using a FRET-CSP reporter peptide, we found that S. mutans UA159 was able to degrade CSP, and that such activity was not significantly different in isogenic mutants with deletion of the protease gene htrA or the competence genes sigX , oppD , and comR. CSP cleavage was also detected in all the wild type strains, indicating that this is a conserved feature in S. mutans. For the XIP pheromone, endogenous production was observed in the supernatants of all 34 tested strains at peak concentrations in culture supernatants that varied between 200 and 26000 nM. Transformation in the presence of exogenous XIP was detected in all but one of the isolates. The efficiency of transformation varied, however, among the different strains, and for those with the highest transformation rates, endogenous XIP peak concentrations in the supernatants were above 2000 nM XIP. We conclude that XIP production and inducing effect on transformation, as well as the ability to degrade CSP, are conserved functions among different S. mutans isolates. Understanding the functionality and conservation of pheromone systems in S. mutans may lead to novel strategies to prevent or treat unbalances in oral microbiomes that may favor diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
16. Atomic Layer Deposition (ALD) of Metal Gates for CMOS.
- Author
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Zhao, Chao and Xiang, Jinjuan
- Subjects
INDIUM gallium zinc oxide ,ATOMIC layer deposition ,COMPLEMENTARY metal oxide semiconductors ,FIELD-effect transistors ,THRESHOLD voltage ,ELECTRON work function - Abstract
Featured Application: Metal gate of CMOS devices. The continuous down-scaling of complementary metal oxide semiconductor (CMOS) field effect transistors (FETs) had been suffering two fateful technical issues, one relative to the thinning of gate dielectric and the other to the aggressive shortening of channel in last 20 years. To solve the first issue, the high-κ dielectric and metal gate technology had been induced to replace the conventional gate stack of silicon dioxide layer and poly-silicon. To suppress the short channel effects, device architecture had changed from planar bulk Si device to fully depleted silicon on insulator (FDSOI) and FinFETs, and will transit to gate all-around FETs (GAA-FETs). Different from the planar devices, the FinFETs and GAA-FETs have a 3D channel. The conventional high-κ/metal gate process using sputtering faces conformality difficulty, and all atomic layer deposition (ALD) of gate stack become necessary. This review covers both scientific and technological parts related to the ALD of metal gates including the concept of effect work function, the material selection, the precursors for the deposition, the threshold voltage (V
t ) tuning of the metal gate in contact with HfO2 /SiO2 /Si. The ALD of n-type metal gate will be detailed systematically, based mainly on the authors' works in last five years, and the all ALD gate stacks will be proposed for the future generations based on the learning. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
17. Dosimetric comparison of circular Eye Physics and Collaborative Ocular Melanoma Study plaques to treat uveal melanoma.
- Author
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Dean, Mary K., Studenski, Matthew T., Paez-Escamilla, Manuel A., Walter, Scott D., Kwon, Deukwoo, Markoe, Arnold M., Harbour, J. William, and Samuels, Stuart E.
- Subjects
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UVEA cancer , *OPTIC disc , *MELANOMA , *EYE , *PHYSICS , *MEETING planning , *MELANOMA treatment - Abstract
We sought to formally compare Collaborative Ocular Melanoma Study (COMS) and similar-shaped (circular) eye physics (EP) plaques dosimetrically by examining both tumor coverage and critical structure doses. The plans of patients with uveal melanoma treated consecutively with eye plaque brachytherapy at a single institution from January 2016 to December 2017 were reviewed. Both a COMS plan and an EP plan using plaques of the same shape were generated for each patient using the Isoaid Plaque Simulator software such that >90% of the tumor + 2 mm margin received 85 Gy over 72 hours from iodine-125 sources. Dose statistics were recorded and analyzed using standard statistical methods. Plans from a total of 62 patients were analyzed. The mean tumor volume was 0.46 cm3 (range: 0.02-2.02), and tumors were located on average 5.89 mm (range: 0-15.0) from the macula and 6.25 mm (range: 0-16.0) from the optic disc. All plans met the treatment planning criteria for tumor coverage and were optimized to reduce dose to the adjacent organs at risk. There were no significant differences in the mean doses to the fovea (mean difference [MD] = −0.87 Gy; 95% confidence interval [CI]: −4.90 to 3.16; p = 0.80), macula (MD = −1.02 Gy; 95% CI: −4.15 to 2.11; p = 0.65), or optic disc (MD = 1.07 Gy; 95% CI: −0.77 to 2.91; p = 0.34) between the COMS and circular EP plaques. Overall, neither the COMS plaques nor the circular EP plaques provided consistently superior dosimetry for the treatment of uveal melanoma. The choice of plaque may be based on other considerations such as cost and surgeon preference. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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18. Spatial distribution of soil moisture estimates using a multiple linear regression model and Korean geostationary satellite (COMS) data.
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Lee, Yonggwan, Jung, Chunggil, and Kim, Seongjoon
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- *
SOIL moisture , *REGRESSION analysis , *GEOSTATIONARY satellites , *LAND surface temperature , *METEOROLOGICAL precipitation - Abstract
Highlights • Generate daily COMS Land Surface Temperature (LST) collected every 15 min. • Develop an multiple linear regression (MLR) model using daily COMS LST and MODIS NDVI data in addition to interpolated precipitation (PCP). • Estimate the Surface Soil Moisture (SSM) from January 2013 to May 2015 based on the MLR model. • Compare the quality of this product with in situ measurements and spatial distribution of the soil moisture index (SMI). Abstract This study attempts to estimate the spatial distribution of the soil moisture (SM) in South Korea (99,260 km2) from January 2013 to May 2015 using a multiple linear regression (MLR) model with data from the Korean multipurpose geostationary Communication, Ocean and Meteorological Satellite (COMS), and land surface temperature (LST) data. The normalized distribution vegetation index (NDVI) from the moderate-resolution imaging spectroradiometer (MODIS) on board the Terra satellite was used to reflect the vegetation variations. Observed precipitation data measured by automatic weather stations (AWSs) operated by the Korea Meteorological Administration (KMA) were collected, and SM data were collected from 38 stations operated by various institutions. The regression coefficients of the MLR model were estimated seasonally considering five days of preceding precipitation. The p-values of all regression coefficients were below 0.05, and all coefficients of determination (R2) ranged from 0.17 to 0.63. Specifically, the R2 of loam in the summer was the highest at 0.63, and most of the R2 values were 0.4 or higher. The results of the SM regression showed that the overall R2 was higher than 0.4 and that the root mean square error (RMSE) was less than 5% at all but a few stations. A time series analysis of the simulated SM revealed that the observed SM data ranged from 0 to 20% for sand, 10 to 30% for loam, 20 to 40% for clay and 30 to 50% for silt. The simulated SM followed the volatility of the observed data in most of the soils. The spatial distribution of the simulated SM showed the same trends with the observed data on the monthly spatial precipitation map. Consequently, the estimated map of the soil moisture index (SMI) can be used to better understand the severity of drought and the variability in the SM. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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19. European Guidelines for Obesity Management in Adults
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Volkan Yumuk, Constantine Tsigos, Martin Fried, Karin Schindler, Luca Busetto, Dragan Micic, Hermann Toplak, and for the Obesity Management Task Force of the European Association for the Study of Obesity
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European guidelines ,Obesity management ,Multidisciplinary ,Primary care ,OMTF ,COMs ,Nutrition. Foods and food supply ,TX341-641 ,Nutritional diseases. Deficiency diseases ,RC620-627 - Abstract
Obesity is a chronic metabolic disease characterised by an increase of body fat stores. It is a gateway to ill health, and it has become one of the leading causes of disability and death, affecting not only adults but also children and adolescents worldwide. In clinical practice, the body fatness is estimated by BMI, and the accumulation of intra-abdominal fat (marker for higher metabolic and cardiovascular disease risk) can be assessed by waist circumference. Complex interactions between biological, behavioural, social and environmental factors are involved in regulation of energy balance and fat stores. A comprehensive history, physical examination and laboratory assessment relevant to the patient's obesity should be obtained. Appropriate goals of weight management emphasise realistic weight loss to achieve a reduction in health risks and should include promotion of weight loss, maintenance and prevention of weight regain. Management of co-morbidities and improving quality of life of obese patients are also included in treatment aims. Balanced hypocaloric diets result in clinically meaningful weight loss regardless of which macronutrients they emphasise. Aerobic training is the optimal mode of exercise for reducing fat mass while a programme including resistance training is needed for increasing lean mass in middle-aged and overweight/obese individuals. Cognitive behavioural therapy directly addresses behaviours that require change for successful weight loss and weight loss maintenance. Pharmacotherapy can help patients to maintain compliance and ameliorate obesity-related health risks. Surgery is the most effective treatment for morbid obesity in terms of long-term weight loss. A comprehensive obesity management can only be accomplished by a multidisciplinary obesity management team. We conclude that physicians have a responsibility to recognise obesity as a disease and help obese patients with appropriate prevention and treatment. Treatment should be based on good clinical care, and evidence-based interventions; should focus on realistic goals and lifelong multidisciplinary management.
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- 2015
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20. Direct Short-Term Forecast of Photovoltaic Power through a Comparative Study between COMS and Himawari-8 Meteorological Satellite Images in a Deep Neural Network
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Minho Kim, Hunsoo Song, and Yongil Kim
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PV power ,direct PV forecast ,Himawari-8 ,COMS ,deep neural network ,Science - Abstract
Meteorological satellite images provide crucial information on solar irradiation and weather conditions at spatial and temporal resolutions which are ideal for short-term photovoltaic (PV) power forecasts. Following the introduction of next-generation meteorological satellites, investigating their application on PV forecasts has become imminent. In this study, Communications, Oceans, and Meteorological Satellite (COMS) and Himawari-8 (H8) satellite images were inputted in a deep neural network (DNN) model for 2 hour (h)- and 1 h-ahead PV forecasts. A one-year PV power dataset acquired from two solar power test sites in Korea was used to directly forecast PV power. H8 was used as a proxy for GEO-KOMPSAT-2A (GK2A), the next-generation satellite after COMS, considering their similar resolutions, overlapping geographic coverage, and data availability. In addition, two different data sampling setups were designed to implement the input dataset. The first setup sampled chronologically ordered data using a relatively more inclusive time frame (6 a.m. to 8 p.m. in local time) to create a two-month test dataset, whereas the second setup randomly sampled 25% of data from each month from the one-year input dataset. Regardless of the setup, the DNN model generated superior forecast performance, as indicated by the lowest normalized mean absolute error (NMAE) and normalized root mean squared error (NRMSE) results in comparison to that of the support vector machine (SVM) and artificial neural network (ANN) models. The first setup results revealed that the visible (VIS) band yielded lower NMAE and NRMSE values, while COMS was found to be more influential for 1 h-ahead forecasts. For the second setup, however, the difference in NMAE results between COMS and H8 was not significant enough to distinguish a clear edge in performance. Nevertheless, this marginal difference and similarity of the results suggest that both satellite datasets can be used effectively for direct short-term PV forecasts. Ultimately, the comparative study between satellite datasets as well as spectral bands, time frames, forecast horizons, and forecast models confirms the superiority of the DNN and offers insights on the potential of transitioning to applying GK2A for future PV forecasts.
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- 2020
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21. Attenuation Correction of X-Band Radar Reflectivity Using Adjacent Multiple Microwave Links
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Min-Seong Kim and Byung Hyuk Kwon
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X-band dual-polarimetric radar ,radar attenuation correction ,multiple microwave links ,COMS ,S-band radar reflectivity ,Science - Abstract
Rain attenuation can hinder the implementation of quantitative precipitation estimations using X-band weather radar. Numerous studies have been conducted on correcting the attenuation of radar reflectivity by utilizing a dual-polarimetric radar and an arbitrary-oriented microwave link; however, there is a need to optimize the required number of microwave links and their locations. In this study, we tested four attenuation correction methods and proposed a novel algorithm based on the sole use of adjacent multiple microwave links. The attenuation of the X-band radar reflectivity was corrected by performing forward iterations at each link, and the correction coefficients were statistically analyzed to reduce the instability problem. The algorithms of each method were evaluated by studying the cases of convective and stratiform rainfall, and then validated by comparing the corrected reflectivity of the X-band radar with the qualitatively controlled reflectivity of the S-band radar. The new method was as efficient as the conventional method based on the specific differential phase of dual-polarimetric radar. Furthermore, the correction coefficient was more effectively optimized and stabilized using seven microwave links rather than a single link, and no further independent reference data were required. In addition, the attenuation correction also accounted for spatiotemporal differentiation depending on the rainfall type, and could recover the physical structure of the rainfall. The method developed herein can facilitate estimations of quantitative rainfall in developing countries where dual-polarization weather radars are not common. The exploitation of microwave link data is a promising method for rainfall remote sensing.
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- 2020
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22. Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and Syringomyelia
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Clare Rusbridge, Felicity Stringer, and Susan P. Knowler
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complex craniosynostosis syndrome ,basilar invagination ,COMS ,Chiari type I malformation ,cine MRI ,balanced steady-state free precession sequence ,Veterinary medicine ,SF600-1100 - Abstract
Chiari-like malformation (CM) and syringomyelia (SM) is a frequent diagnosis in predisposed brachycephalic toy breeds since increased availability of MRI. However, the relevance of that MRI diagnosis has been questioned as CM, defined as identification of a cerebellar herniation, is ubiquitous in some breeds and SM can be asymptomatic. This article reviews the current knowledge of neuroanatomical changes in symptomatic CM and SM and diagnostic imaging modalities used for the clinical diagnosis of CM-pain or myelopathy related to SM. Although often compared to Chiari type I malformation in humans, canine CM-pain and SM is more comparable to complex craniosynostosis syndromes (i.e., premature fusion of multiple skull sutures) characterized by a short skull (cranial) base, rostrotentorial crowding with rostral forebrain flattening, small, and ventrally orientated olfactory bulbs, displacement of the neural tissue to give increased height of the cranium and further reduction of the functional caudotentorial space with hindbrain herniation. MRI may further reveal changes suggesting raised intracranial pressure such as loss of sulci definition in conjunction with ventriculomegaly. In addition to these brachycephalic changes, dogs with SM are more likely to have craniocervical junction abnormalities including rostral displacement of the axis and atlas with increased odontoid angulation causing craniospinal junction deformation and medulla oblongata elevation. Symptomatic SM is diagnosed on the basis of signs of myelopathy and presence of a large syrinx that is consistent with the neuro-localization. The imaging protocol should establish the longitudinal and transverse extent of the spinal cord involvement by the syrinx. Phantom scratching and cervicotorticollis are associated with large mid-cervical syringes that extend to the superficial dorsal horn. If the cause of CSF channel disruption and syringomyelia is not revealed by anatomical MRI then other imaging modalities may be appropriate with radiography or CT for any associated vertebral abnormalities.
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- 2018
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23. Improvements of a COMS Land Surface Temperature Retrieval Algorithm Based on the Temperature Lapse Rate and Water Vapor/Aerosol Effect
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A-Ra Cho, Youn-Young Choi, and Myoung-Seok Suh
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land surface temperature ,split-window algorithm ,COMS ,MODIS ,Science - Abstract
The National Meteorological Satellite Center in Korea retrieves land surface temperature (LST) by applying the split-window LST algorithm (CSW_v1.0) to Communication, Ocean, and Meteorological Satellite (COMS) data. Considerable errors were detected under conditions of high water vapor content or temperature lapse rates during validation with Moderate Resolution Imaging Spectroradiometer (MODIS) LST because of the too simplified LST algorithm. In this study, six types of LST retrieval equations (CSW_v2.0) were developed to upgrade the CSW_v1.0. These methods were developed by classifying “dry,” “normal,” and “wet” cases for day and night and considering the relative sizes of brightness temperature difference (BTD) values. Similar to CSW_v1.0, the LST retrieved by CSW_v2.0 had a correlation coefficient of 0.99 with the prescribed LST and a slightly larger bias of −0.03 K from 0.00K; the root mean square error (RMSE) improved from 1.41 K to 1.39 K. In general, CSW_v2.0 improved the retrieval accuracy compared to CSW_v1.0, especially when the lapse rate was high (mid-day and dawn) and the water vapor content was high. The spatial distributions of LST retrieved by CSW_v2.0 were found to be similar to the MODIS LST independently of the season, day/night, and geographic locations. The validation using one year’s MODIS LST data showed that CSW_v2.0 improved the retrieval accuracy of LST in terms of correlations (from 0.988 to 0.989), bias (from −1.009 K to 0.292 K), and RMSEs (from 2.613 K to 2.237 K).
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- 2015
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24. A New Application of Unsupervised Learning to Nighttime Sea Fog Detection.
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Shin, Daegeun and Kim, Jae-Hwan
- Abstract
This paper presents a nighttime sea fog detection algorithm incorporating unsupervised learning technique. The algorithm is based on data sets that combine brightness temperatures from the 3.7 μm and 10.8 μm channels of the meteorological imager (MI) onboard the Communication, Ocean and Meteorological Satellite (COMS), with sea surface temperature from the Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA). Previous algorithms generally employed threshold values including the brightness temperature difference between the near infrared and infrared. The threshold values were previously determined from climatological analysis or model simulation. Although this method using predetermined thresholds is very simple and effective in detecting low cloud, it has difficulty in distinguishing fog from stratus because they share similar characteristics of particle size and altitude. In order to improve this, the unsupervised learning approach, which allows a more effective interpretation from the insufficient information, has been utilized. The unsupervised learning method employed in this paper is the expectation-maximization (EM) algorithm that is widely used in incomplete data problems. It identifies distinguishing features of the data by organizing and optimizing the data. This allows for the application of optimal threshold values for fog detection by considering the characteristics of a specific domain. The algorithm has been evaluated using the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) vertical profile products, which showed promising results within a local domain with probability of detection (POD) of 0.753 and critical success index (CSI) of 0.477, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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25. Mortality after deferral of treatment or no treatment for choroidal melanoma.
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Straatsma, Bradley R., Diener-West, Marie, Caldwell, Robert, Engstrom Jr, Robert E., Engstrom, Robert E, and Collaborative Ocular Melanoma Study Group*
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MELANOMA treatment , *NEUROENDOCRINE tumors , *CLINICAL trials , *RADIOISOTOPE brachytherapy , *DISEASE progression , *COMPARATIVE studies , *ENUCLEATION of the eye , *LONGITUDINAL method , *RESEARCH methodology , *MEDICAL cooperation , *MELANOMA , *RESEARCH , *SURVIVAL , *EVALUATION research , *UVEA , *PASSIVE euthanasia , *TUMOR treatment , *TUMORS - Abstract
Purpose: To report mortality of patients who were eligible for enrollment in the Collaborative Ocular Melanoma Study (COMS) clinical trials of medium-sized choroidal melanoma or large-sized choroidal melanoma but chose to defer treatment or receive no melanoma treatment.Design: Prospective nonrandomized multicenter cohort study as an adjunct to COMS randomized clinical trials.Methods: Patient follow-up procedures included examinations, correspondence, telephone contacts, and National Death Index searches. Primary outcome was patient death measured by all-cause mortality. Secondary outcomes were melanoma treatment and melanoma metastasis.Results: Of 77 patients eligible for COMS clinical trials who chose to defer or receive no melanoma treatment, 61 were appropriate candidates and 45 (74%) enrolled in the natural history study (NHS). In all, 42 patients (42 eyes) had medium melanoma, and the median follow-up was 5.3 years (range, 4-10.7 years). In all, 22 patients (52%) had subsequent melanoma treatment, and 20 (48%) had no melanoma treatment. For the 42 patients, Kaplan-Meier estimate of 5-year mortality was approximately 30% [95% confidence interval (CI), 18%-47%]. For COMS medium melanoma trial, 5-year mortality was 18% (95% CI, 16%-20%), not statistically significantly different from the NHS patients. After adjusting for differences in age and longest basal diameter, the 5-year risk of death for NHS patients versus COMS trial patients was 1.54 (95% CI, 0.93-2.56). Three patients had large melanoma. Melanoma metastasis was confirmed or suspected in 8 (42%) of 19 deaths.Conclusion: Greater mortality and higher risk of death for NHS patients are probative but not conclusive evidence of a beneficial, life-extending effect of medium melanoma treatment. [ABSTRACT FROM AUTHOR]- Published
- 2018
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26. Improved detection of low stratus and fog at dawn from dual geostationary (COMS and FY-2D) satellites.
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Yoo, Jung-Moon, Choo, Gyo-Hwang, Lee, Kwon-Ho, Wu, Dong L., Yang, Jung-Hyun, Park, Jun-Dong, Choi, Yong-Sang, Shin, Dong-Bin, Jeong, Jin-Hee, and Yoo, Jung-Min
- Subjects
- *
STRATUS clouds , *FOG , *COMPUTER simulation , *GEOSTATIONARY satellites , *METEOROLOGICAL satellites , *METEOROLOGY - Abstract
A novel method was proposed to detect low stratus and fog (LSF) at dawn during the summertime using near-simultaneous observations from dual geostationary-orbit satellites (GEOs): the Korean Communication, Ocean and Meteorological Satellite (COMS; 128.2°E) and the Chinese Feng-Yun-2D (FY-2D; 86.5°E). The orbital positions of the GEOs provided a large difference (~46.5°) in the viewing zenith angle (VZA) in the study region (122–132°E, 32.5–42.5°N) and high contrast observations at dawn. Numerical simulations were carried out to derive the optical properties of the LSF and the radiative differences between the GEOs due to both the VZA and spectral response function (SRF). The conventional threshold method, which used the visible reflectance at 0.67 μm (R 0.67 ) and the brightness temperature difference between 3.7 μm and 11 μm (BTD 3.7–11 ), had limitations in detecting LSF at dawn due to weak visible light and fast night-to-day transition. We utilized the observed stereo differences (ΔR 0.67 , ΔBTD 3.7–11 ) between the two GEOs to improve LSF detection. The dual-satellite observations were verified with ground-based data from 45 stations in South Korea co-located with each GEO pixel. The ΔR 0.67 threshold value showed better accuracy (78% vs. 67%) than the conventional R 0.67 threshold method. In addition, the ΔBTD 3.7–11 threshold was better (55% vs. 38%) than the BTD 3.7–11 threshold. The dual-satellite method allowed more reliable LSF detection using the combination of ΔR 0.67 and R 0.67 , particularly for LSF without cumuliform or high clouds. Our method is applicable to multiple geostationary satellites for continuous LSF monitoring. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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27. Simulation of Human Eye for Ophthalmic Brachytherapy Dosimetry Using MCNP-4C Code
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Asadi, S., Farhad Masoudi, S., Shahriari, M., Magjarevic, Ratko, editor, Dössel, Olaf, editor, and Schlegel, Wolfgang C., editor
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- 2009
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28. Assessment of Surface Urban Heat Islands over Three Megacities in East Asia Using Land Surface Temperature Data Retrieved from COMS
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Youn-Young Choi, Myoung-Seok Suh, and Ki-Hong Park
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land surface temperature ,surface urban heat island ,COMS ,spatio-temporal variation ,Science - Abstract
Surface urban heat island (SUHI) impacts control the exchange of sensible heat and latent heat between land and atmosphere and can worsen extreme climate events, such as heat waves. This study assessed SUHIs over three megacities (Seoul, Tokyo, Beijing) in East Asia using one-year (April 2011–March 2012) land surface temperature (LST) data retrieved from the Communication, Ocean and Meteorological Satellite (COMS). The spatio-temporal variations of SUHI and the relationship between SUHI and vegetation activity were analyzed using hourly cloud-free LST data. In general, the LST was higher in low latitudes, low altitudes, urban areas and dry regions compared to high latitudes, high altitudes, rural areas and vegetated areas. In particular, the LST over the three megacities was always higher than that in the surrounding rural areas. The SUHI showed a maximum intensity (10–13 °C) at noon during the summer, irrespective of the geographic location of the city, but weak intensities (4–7 °C) were observed during other times and seasons. In general, the SUHI intensity over the three megacities showed strong seasonal (diurnal) variations during the daytime (summer) and weak seasonal (diurnal) variations during the nighttime (other seasons). As a result, the temporal variation pattern of SUHIs was quite different from that of urban heat islands, and the SUHIs showed a distinct maximum at noon of the summer months and weak intensities during the nighttime of all seasons. The patterns of seasonal and diurnal variations of the SUHIs were clearly dependent on the geographic environment of cities. In addition, the intensity of SUHIs showed a strong negative relationship with vegetation activity during the daytime, but no such relationship was observed during the nighttime. This suggests that the SUHI intensity is mainly controlled by differences in evapotranspiration (or the Bowen ratio) between urban and rural areas during the daytime.
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- 2014
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29. Development and Intercomparison Study of an Atmospheric Motion Vector Retrieval Algorithm for GEO-KOMPSAT-2A
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Soo Min Oh, Régis Borde, Manuel Carranza, and In-Chul Shin
- Subjects
GK-2A ,atmospheric motion vector (AMV) ,Himawari-8 ,target box size ,height assignment ,COMS ,MTG ,intercomparison ,Science - Abstract
We derived an atmospheric motion vector (AMV) algorithm for the Geostationary Korea Multipurpose Satellite (GEO-KOMPSAT-2A; GK-2A) launched on 4 December 2018, using the Advanced Himawari Imager (AHI) onboard Himawari-8, which is very similar to the Advanced Meteorological Imager onboard GK-2A. This study clearly describes the main steps in our algorithm and optimizes it for the target box size and height assignment methods by comparing AMVs with numerical weather prediction (NWP) and rawinsonde profiles for July 2016 and January 2017. Target box size sensitivity tests were performed from 8 × 8 to 48 × 48 pixels for three infrared channels and from 16 × 16 to 96 × 96 pixels for one visible channel. The results show that the smaller box increases the speed, whereas the larger one slows the speed without quality control. The best target box sizes were found to be 16 × 16 for CH07, 08, and 13, and 48 × 48 pixels for CH03. Height assignment sensitivity tests were performed for several methods, such as the cross-correlation coefficient (CCC), equivalent blackbody temperature (EBBT), infrared/water vapor (IR/WV) intercept, and CO2 slicing methods for a cloudy target as well as normalized total contribution (NTC) and normalized total cumulative contribution (NTCC) for a clear-air target. For a cloudy target, the CCC method is influenced by the quality of the cloud’s top pressure. Better results were found when using EBBT and IR/WV intercept methods together rather than individually. Furthermore, CO2 slicing had the best statistics. For a clear-air target, the combined use of NTC and NTCC had the best statistics. Additionally, the mean vector difference, root-mean-square (RMS) vector difference, bias, and RMS error (RMSE) between GK-2A AMVs and NWP or rawinsonde were smaller by approximately 18.2% on average than in the case of the Communication, Ocean and Meteorology Satellite (COMS) AMVs. In addition, we verified the similarity between GK-2A and Meteosat Third Generation (MTG) AMVs using the AHI of Himawari-8 from 21 July 2016. This similarity can provide evidence that the GK-2A algorithm works properly because the GK-2A AMV algorithm borrows many methods of the MTG AMV algorithm for geostationary data and inversion layer corrections. The Pearson correlation coefficients in the speed, direction, and height of the prescribed GK-2A and MTG AMVs were larger than 0.97, and the corresponding bias/RMSE were0.07/2.19 m/s, 0.21/14.8°, and 2.61/62.9 hPa, respectively, considering common quality indicator with forecast (CQIF) > 80.
- Published
- 2019
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30. Atomic Layer Deposition (ALD) of Metal Gates for CMOS
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Chao Zhao and Jinjuan Xiang
- Subjects
COMS ,metal gate ,atomic layer deposition ,high-κ dielectric ,threshold voltage ,flatband voltage ,effective work function ,effective oxide thickness ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The continuous down-scaling of complementary metal oxide semiconductor (CMOS) field effect transistors (FETs) had been suffering two fateful technical issues, one relative to the thinning of gate dielectric and the other to the aggressive shortening of channel in last 20 years. To solve the first issue, the high-κ dielectric and metal gate technology had been induced to replace the conventional gate stack of silicon dioxide layer and poly-silicon. To suppress the short channel effects, device architecture had changed from planar bulk Si device to fully depleted silicon on insulator (FDSOI) and FinFETs, and will transit to gate all-around FETs (GAA-FETs). Different from the planar devices, the FinFETs and GAA-FETs have a 3D channel. The conventional high-κ/metal gate process using sputtering faces conformality difficulty, and all atomic layer deposition (ALD) of gate stack become necessary. This review covers both scientific and technological parts related to the ALD of metal gates including the concept of effect work function, the material selection, the precursors for the deposition, the threshold voltage (Vt) tuning of the metal gate in contact with HfO2/SiO2/Si. The ALD of n-type metal gate will be detailed systematically, based mainly on the authors’ works in last five years, and the all ALD gate stacks will be proposed for the future generations based on the learning.
- Published
- 2019
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31. Probability Index of Low Stratus and Fog at Dawn using Dual Geostationary Satellite Observations from COMS and FY-2D near the Korean Peninsula
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Jung-Hyun Yang, Jung-Moon Yoo, Yong-Sang Choi, Dong Wu, and Jin-Hee Jeong
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fog ,LSF ,dawn ,probability index ,COMS ,FY-2D ,remote sensing ,threshold ,radiative transfer model ,Science - Abstract
We developed a new remote sensing method for detecting low stratus and fog (LSF) at dawn in terms of probability index (PI) of LSF from simultaneous stereo observations of two geostationary-orbit satellites; the Korean Communication, Ocean, and Meteorological Satellite (COMS; 128.2°E); and the Chinese FengYun satellite (FY-2D; 86.5°E). The algorithm was validated near the Korean Peninsula between the months of April and August from April 2012 to June 2015, by using surface observations at 45 meteorological stations in South Korea. The optical features of LSF were estimated by using satellite retrievals and simulated data from the radiative transfer model. The PI was calculated using the combination of three satellite-observed variables: 1) the reflectance at 0.67 μm (R0.67) from COMS, and 2) the FY-2D R0.67 minus the COMS R0.67 (△R0.67) and 3) the FY-2D-COMS difference in the brightness temperature difference between 3.7 and 11.0 μm (ΔBTD3.7-11). The three variables, adopted from the top three probability of detection (POD) scores for their fog detection thresholds: △R0.67 (0.82) > ΔBTD3.7-11 (0.73) > R0.67 (0.70) > BTD3.7-11 (0.51). The LSF PI for this algorithm was significantly better in the two case studies compared to that using COMS only (i.e., R0.67 or BTD3.7-11), so that this improvement was due to △R0.67 and ΔBTD3.7-11. Overall, PI in the LSF spatial distribution has the merits of a high detection rate, a specific probability display, and a low rate of seasonality and variability in detection accuracy. Therefore, PI would be useful for monitoring LSF in near-real-time, and to further its forecast ability, using next-generation satellites.
- Published
- 2019
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32. Toward Improved Solar Irradiance Forecasts: Comparison of the Global Horizontal Irradiances Derived from the COMS Satellite Imagery Over the Korean Peninsula.
- Author
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Kim, Chang, Kim, Hyun-Goo, Kang, Yong-Heack, and Yun, Chang-Yeol
- Subjects
SPECTRAL irradiance ,SOLAR radiation ,CLIMATOLOGY ,GLOBAL warming - Abstract
This study introduces the University of Arizona Solar Irradiance Based on Satellite/Korea Institute of Energy Research, which is usually called UASIBS/KIER model. Then the evaluation of modeling performance is done against the ground observations for the instantaneous, hourly, and daily time scales over the Korean Peninsula in this study. The relative root mean square error for the instantaneous time scale is 7.4 and 16.7% for the clear and cloudy skies, respectively. The hourly mean estimates are compared with the in situ measurements from 35 ground observation stations, resulting in a relative root mean square error ranging from 9.1 to 15.5%. The daily aggregates are proven as the most reliable estimates. The UASIBS/KIER estimates are also compared with the routine solar insolation product from the Korea Meteorological Administration. Finally, the solar energy resource map has been built by the daily solar irradiance derived from the UASIBS/KIER model, followed by its comparison with the other gridded datasets. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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33. Evaluation of Land Surface Temperature Operationally Retrieved from Korean Geostationary Satellite (COMS) Data
- Author
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A-Ra Cho and Myoung-Seok Suh
- Subjects
land surface temperature ,split-window algorithm ,COMS ,MODIS ,evaluation ,Science - Abstract
We evaluated the precision of land surface temperature (LST) operationally retrieved from the Korean multipurpose geostationary satellite, Communication, Ocean and Meteorological Satellite (COMS). The split-window (SW)-type retrieval algorithm was developed through radiative transfer model simulations under various atmospheric profiles, satellite zenith angles, surface emissivity values and surface lapse rate conditions using Moderate Resolution Atmospheric Transmission version 4 (MODTRAN4). The estimation capabilities of the COMS SW (CSW) LST algorithm were evaluated for various impacting factors, and the retrieval accuracy of COMS LST data was evaluated with collocated Moderate Resolution Imaging Spectroradiometer (MODIS) LST data. The surface emissivity values for two SW channels were generated using a vegetation cover method. The CSW algorithm estimated the LST distribution reasonably well (averaged bias = 0.00 K, Root Mean Square Error (RMSE) = 1.41 K, correlation coefficient = 0.99); however, the estimation capabilities of the CSW algorithm were significantly impacted by large brightness temperature differences and surface lapse rates. The CSW algorithm reproduced spatiotemporal variations of LST comparing well to MODIS LST data, irrespective of what month or time of day the data were collected from. The one-year evaluation results with MODIS LST data showed that the annual mean bias, RMSE and correlation coefficient for the CSW algorithm were −1.009 K, 2.613 K and 0.988, respectively.
- Published
- 2013
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34. CURRENT CONTROLLED TRANSCONDUCTANCE AMPLIFIER (CCTA) USING ADVANCED DESIGN SYSTEM
- Author
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Mayuri A. Deshmukh and U.A. Kshirsagar
- Subjects
Hardware_GENERAL ,mosfts ,lcsh:Electronics ,Hardware_INTEGRATEDCIRCUITS ,lcsh:TK7800-8360 ,Hardware_PERFORMANCEANDRELIABILITY ,coms ,ccccta ,advanced design system ,Hardware_LOGICDESIGN - Abstract
Complementary Metal Oxide Semiconductor (CMOS) is a technology used to produce integrated circuit. CMOS circuits are found in several types of electronic components, including microprocessors, batteries and digital camera image sensors. The MOS in CMOS refers to the transistor in a CMOS component called MOSFETs (metal oxide semiconductor field-effect transistors). In the project we are going to design novel CCCCTA, developed in CMOS technology using Advanced Design System (ADS). Current conveyors are unity gain active building block having high linearity, wide dynamic range and provide higher gain-bandwidth product. The current conveyors operate at low voltage supplies and consume less power. It has high input impedance, low output impedance, high CMRR and high slew rate. The current mode circuits such as Current conveyors have emerged as an important class of circuits in the field of analog electronics. The new structured CCCCTA the balanced differential-pair structure is used instead of the trans-linear structure as in the original CCCCTA and our proposed block are the requirements of bias current which is used to control the parasitic resistance at the input current port and the number of MOSFETs.
- Published
- 2020
- Full Text
- View/download PDF
35. Icing Detection over East Asia from Geostationary Satellite Data Using Machine Learning Approaches
- Author
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Seongmun Sim, Jungho Im, Sumin Park, Haemi Park, Myoung Hwan Ahn, and Pak-wai Chan
- Subjects
icing detection ,machine learning ,geostationary satellite data ,COMS ,Himawari-8 ,Science - Abstract
Even though deicing or airframe coating technologies continue to develop, aircraft icing is still one of the critical threats to aviation. While the detection of potential icing clouds has been conducted using geostationary satellite data in the US and Europe, there is not yet a robust model that detects potential icing areas in East Asia. In this study, we proposed machine-learning-based icing detection models using data from two geostationary satellites—the Communication, Ocean, and Meteorological Satellite (COMS) Meteorological Imager (MI) and the Himawari-8 Advanced Himawari Imager (AHI)—over Northeast Asia. Two machine learning techniques—random forest (RF) and multinomial log-linear (MLL) models—were evaluated with quality-controlled pilot reports (PIREPs) as the reference data. The machine-learning-based models were compared to the existing models through five-fold cross-validation. The RF model for COMS MI produced the best performance, resulting in a mean probability of detection (POD) of 81.8%, a mean overall accuracy (OA) of 82.1%, and mean true skill statistics (TSS) of 64.0%. One of the existing models, flight icing threat (FIT), produced relatively poor performance, providing a mean POD of 36.4%, a mean OA of 61.0, and a mean TSS of 9.7%. The Himawari-8 based models also produced performance comparable to the COMS models. However, it should be noted that very limited PIREP reference data were available especially for the Himawari-8 models, which requires further evaluation in the future with more reference data. The spatio-temporal patterns of the icing areas detected using the developed models were also visually examined using time-series satellite data.
- Published
- 2018
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- View/download PDF
36. Modelling and Preliminary Prediction of Thermal Balance Test for COMS
- Author
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Hyoung Yoll Jun, Jung-Hoon Kim, and Cho Young Han
- Subjects
COMS ,geostationary orbit ,thermal control ,thermal analysis ,thermal balance test ,thermal vacuum chamber ,Astronomy ,QB1-991 - Abstract
COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and developed by KARI for communication, ocean and meteorological observations. It will be tested under vacuum and very low temperature conditions in order to verify thermal design of COMS. The test will be performed by using KARI large thermal vacuum chamber, which was developed by KARI, and the COMS will be the first flight satellite tested in this chamber. The purposes of thermal balance test are to correlate analytical model used for design evaluation and predicting temperatures, and to verify and adjust thermal control concept. KARI has plan to use heating plates to simulate space hot condition especially for radiator panels of satellite such as north and south panels. They will be controlled from 90 K to 273 K by circulating GN2 and LN2 alternatively according to the test phases, while the main shroud of the vacuum chamber will be under constant temperature, 90 K, during all thermal balance test. This paper presents thermal modelling including test chamber, heating plates and the satellite without solar array wing and Ka-band reflectors and discusses temperature prediction during thermal balance test.
- Published
- 2009
- Full Text
- View/download PDF
37. Analysis and Design of the Automatic Flight Dynamics Operations For Geostationary Satellite Mission
- Author
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Byoung-Sun Lee, Yoola Hwang, Sangwook Park, Young-Ran Lee, and Javier Santiago Noguero Galilea
- Subjects
satellite orbit ,flight dynamics ,mission control ,automation ,COMS ,Astronomy ,QB1-991 - Abstract
Automation of the key flight dynamics operations for the geostationary orbit satellite mission is analyzed and designed. The automation includes satellite orbit determination, orbit prediction, event prediction, and fuel accounting. An object-oriented analysis and design methodology is used for design of the automation system. Automation scenarios are investigated first and then the scenarios are allocated to use cases. Sequences of the use cases are diagramed. Then software components and graphical user interfaces are designed for automation. The automation will be applied to the Communication, Ocean, and Meteorology Satellite (COMS) flight dynamics system for daily routine operations.
- Published
- 2009
- Full Text
- View/download PDF
38. Development of COMS DATS C&M S/W
- Author
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Su-Jun Kim, Durk-Jong Park, In-Hoi Koo, and Sang-Il Ahn
- Subjects
COMS ,C&M ,data acquisition and transmission ,image data acquisition and control ,Astronomy ,QB1-991 - Abstract
COMS DATS C&M software is an integrated management system providing control and monitoring functionalities for COMS IDACS (Image Data Acquisition and Control System). DATS C&M S/W consists of a system management module, a control and monitoring module, a data management module, and a trend analysis module. COMS SOC is supposed to operate IDACS as a backup of MSC. Especially, for the backup operation, the control and monitoring module of DATS C&M S/W is designed to support the synchronization of the two IDACS systems. This paper describes design, implementation, and result of development of DATS C&M S/W.
- Published
- 2009
- Full Text
- View/download PDF
39. Antenna Pointing to the Geo Satellite Using Converted NORAD TLE from Osculating Orbital Elements
- Author
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Byoung-Sun Lee, Hae-Yeon Kim, Yoola Hwang, and Jaehoon Kim
- Subjects
NORAD TLE ,COMS ,antenna pointing ,Astronomy ,QB1-991 - Abstract
Antenna pointing analysis for a geostationary satellite has been performed for using the NORAD Two-Line-Elements (TLE) converted from osculating Keplerian orbital elements. In order to check the possibility of the reception of the satellite signal, the antenna offset angles have been derived for the Communications, Ocean, and Meteorological Satellite (COMS) which carries out weekly East-West and North-South station-keeping maneuvers and twice a day thruster assisted momentum dumping. Throughout the analysis, it is shown that the use of converted NORAD TLE simplifies the antenna pointing related interfaces in satellite mission control system. For a highly eccentric transfer orbit cases, further analysis presents that the converted NORAD TLE from near apogee gives more favorable results.
- Published
- 2007
- Full Text
- View/download PDF
40. Analysis of Damage Probability for Collision Between Space Debris and a Satellite in Low-Earth Orbit
- Author
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Jae-Eun Lee, Sang-Young Park, Young-Rok Kim, Kyu-Hong Choi, Eunghyun Kim, and Gyu-Sun Kim
- Subjects
COMS ,antenna pointing ,space debris ,collision probability ,satellite damage ,Astronomy ,QB1-991 - Abstract
Space environment becomes more hazardous for satellite because of increasing number of space debris. This research is to analyze collision hazards between KOMPSAT 3 in low-earth orbit and space debris generated by the explosion of FengYun satellite on the January 11, 2007. Based on the observed data of the space debris from FengYun satellite, the mass and number distribution of the debris are estimated including undetectable debris from the explosion of FengYun satellite. The spatial density and flux for the space debris can be calculated according to size. This study also brings out the analysis for the assessment of collision probability and damage probability. The algorithm developed in the current paper can be used to estimate the level of risk due to space debris for the satellites that will be launched in the future.
- Published
- 2007
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- View/download PDF
41. Determination of User Distribution Image Size and Position of Each Observation Area of Meteorological Imager in COMS
- Author
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Jeong-Soo Seo, Seok-Bae Seo, and Eun-Kyou Kim
- Subjects
COMS ,meteorological imager ,field of view ,the geostationary projection ,observation area ,observation scheduling ,Astronomy ,QB1-991 - Abstract
In this paper, requirements of Meteorological Administration about Meteorological Imager (MI) of Communications, Ocean and Meteorological Satellite (COMS) is analyzed for the design of COMS ground station and according to the analysis results, the distribution image size of each observation area suitable for satellite Field Of View (FOV) stated at the requirements of meteorological administration is determined and the precise satellite FOV and the size of distribution image is calculated on the basis of the image size of the determined observation area. The results in this paper were applied to the detailed design for COMS ground station and also are expected to be used for the future observation scheduling and the scheduling of distribution of user data.
- Published
- 2006
- Full Text
- View/download PDF
42. Station-Keeping For COMS Satellite by Analytic Methods
- Author
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Young-Rok Kim, Hae-Yeon Kim, Sang-Young Park, Byoung-Sun Lee, Jae Woo Park, and Kyu-Hong Choi
- Subjects
station-keeping ,geostationary orbit maneuver ,COMS ,Astronomy ,QB1-991 - Abstract
In this paper, an automation algorithm of analyzing and scheduling the station-keeping maneuver is presented for Communication, Ocean and Meteorological Satellite (COMS). The perturbation analysis for keeping the position of the geostationary satellite is performed by analytic methods. The east/west and north/south station-keeping maneuvers are simulated for COMS. Weekly east/west and biweekly north/south station-keeping maneuvers are investigated for a period of one year. Various station-keeping orbital parameters are analyzed. As the position of COMS is not yet decided at either 128.2°E or 116.0°E, both cases are simulated. For the case of 128.2°E, east/west station-keeping requires Δ V of 3.50m/s and north/south station-keeping requires Δ V of 52.71m/s for the year 2009. For the case of 116.0°E, Δ V of 3.86m/s and Δ V of 52.71m/s are required for east/west and north/south station-keeping, respectively. The results show that the station-keeping maneuver of COMS is more effective at 128.2°E.
- Published
- 2006
- Full Text
- View/download PDF
43. Investigating the dosimetric impact of seed location uncertainties in Collaborative Ocular Melanoma Study–based eye plaques.
- Author
-
Johnson, Jedediah E., Deufel, Christopher L., and Furutani, Keith M.
- Subjects
- *
EYE cancer , *MELANOMA treatment , *GAUSSIAN processes , *DEGREES of freedom , *RADIATION dosimetry , *CANCER treatment - Abstract
Purpose To quantify the dosimetric effects of random and systematic seed position uncertainties in Collaborative Ocular Melanoma Study–based eye plaques. Methods and Materials An eye plaque dose calculation routine was created using Task Group 43 formalism. A variety of clinical configurations were simulated, including two seed models: 125 I and 103 Pd, three eye plaque sizes, and eight plaque/eye orientations. Dose was calculated at four ocular anatomic sites and three central axis plaque depths. Random seed positional uncertainty was modeled by adding Gaussian random displacements, in one of three seed-motion degrees of freedom, to each seed's nominal coordinate. Distributions of dosimetric outcomes were obtained and fitted after 10 6 randomizations. Similar analysis was performed for deterministic, systematic shifts of the plaque along the eye surface and radially from the globe center. Results Random seed placement uncertainties of 0.2-mm root mean square (RMS) (amplitude) produce dose changes that are typically <4% for each degree of freedom (95% confidence interval). Systematic seed placement uncertainties are generally greater than random uncertainty 95% confidence intervals (factor of 0.72–2.15), with the relative magnitudes depending on plaque size and location of interest. Eye plaque dosimetry is most sensitive to seed movement toward the center of the eye. Dosimetric uncertainty also increases with increasing dose gradients, which are typically greatest near the inner sclera, with smaller plaques, and with lower energy radionuclides (e.g., 103 Pd). Conclusions Dosimetric uncertainties due to the random seed positional displacements anticipated in the clinic are expected to be <4% for each degree of freedom in most circumstances. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
44. Geospatial blending to improve spatial mapping of precipitation with high spatial resolution by merging satellite-based and ground-based data.
- Author
-
Jongjin, Baik, Jongmin, Park, Dongryeol, Ryu, and Minha, Choi
- Subjects
METEOROLOGICAL precipitation ,HYDROLOGY ,METEOROLOGICAL satellites ,GEOGRAPHIC spatial analysis ,RAINFALL - Abstract
Estimating accurate spatial distribution of precipitation is important for understanding the hydrologic cycle and various hydro-environmental applications. Satellite-based precipitation data have been widely used to measure the spatial distribution of precipitation over large extents, but an improvement in accuracy is still needed. In this study, three different merging techniques (Conditional Merging, Geographical Differential Analysis and Geographical Ratio Analysis) were used to merge precipitation estimations from Communication, Ocean and Meteorological Satellite (COMS) Rainfall Intensity data and ground-based measurements. Merged products were evaluated with varying rain-gauge network densities and accumulation times. The results confirmed that accuracy of detecting quantitative rainfall was improved as the accumulation time and network density increased. Also, the impact of spatial heterogeneity of precipitation on the merged estimates was investigated. Our merging techniques reproduced accurate spatial distribution of rainfall by adopting the advantages of both gauge and COMS estimates. The efficacy of the merging techniques was particularly pronounced when the spatial heterogeneity of hourly rainfall, quantified by variance of rainfall, was greater than 10 mm
2 /accumulation time2 . Among the techniques analysed, Conditional Merging performed the best, especially when the gauge density was low. This study demonstrates the utility of the COMS Rainfall Intensity product, which has a shorter latency time (1 h) and higher spatio-temporal resolution (hourly, 4 km by 4 km) than other widely used satellite precipitation products in estimating precipitation using merging techniques with ground-based point measurements. The outcome has important implications for various hydrologic modelling approaches, especially for producing near real-time products. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
45. European Guidelines for Obesity Management in Adults.
- Author
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Yumuk, Volkan, Tsigos, Constantine, Fried, Martin, Schindler, Karin, Busetto, Luca, Micic, Dragan, and Toplak, Hermann
- Subjects
OBESITY ,BODY mass index ,WAIST circumference ,WEIGHT loss ,QUALITY of life ,LOW-calorie diet ,AEROBIC exercises ,COGNITIVE therapy - Abstract
Obesity is a chronic metabolic disease characterised by an increase of body fat stores. It is a gateway to ill health, and it has become one of the leading causes of disability and death, affecting not only adults but also children and adolescents worldwide. In clinical practice, the body fatness is estimated by BMI, and the accumulation of intra-abdominal fat (marker for higher metabolic and cardiovascular disease risk) can be assessed by waist circumference. Complex interactions between biological, behavioural, social and environmental factors are involved in regulation of energy balance and fat stores. A comprehensive history, physical examination and laboratory assessment relevant to the patient's obesity should be obtained. Appropriate goals of weight management emphasise realistic weight loss to achieve a reduction in health risks and should include promotion of weight loss, maintenance and prevention of weight regain. Management of co-morbidities and improving quality of life of obese patients are also included in treatment aims. Balanced hypocaloric diets result in clinically meaningful weight loss regardless of which macronutrients they emphasise. Aerobic training is the optimal mode of exercise for reducing fat mass while a programme including resistance training is needed for increasing lean mass in middle-aged and overweight/obese individuals. Cognitive behavioural therapy directly addresses behaviours that require change for successful weight loss and weight loss maintenance. Pharmacotherapy can help patients to maintain compliance and ameliorate obesity-related health risks. Surgery is the most effective treatment for morbid obesity in terms of long-term weight loss. A comprehensive obesity management can only be accomplished by a multidisciplinary obesity management team. We conclude that physicians have a responsibility to recognise obesity as a disease and help obese patients with appropriate prevention and treatment. Treatment should be based on good clinical care, and evidence-based interventions; should focus on realistic goals and lifelong multidisciplinary management. © 2015 S. Karger GmbH, Freiburg [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
46. High Temperature Measurement Using Very High Shutter Speed to Avoid Image Saturation.
- Author
-
Zhen Ma and Yang Zhang
- Subjects
- *
PYROMETRY , *IMAGE processing , *COLOR temperature , *TUNGSTEN lamps , *DIGITAL cameras , *HIGH-speed photography - Abstract
This paper explores the adaptation of the two-colour principle to develop a high-speed colour temperature correlation system, which is able to cover a range of temperature that is challenging to achieve before. A colour digital camera has built in RGB filters. It is possible to measure the temperature from the ratio of intensity of the green and red pixels using the two-colour principle based on the expansion of the Plank's radiation law. In this study, experiments were carried out using a temperature calibrated tungsten ribbon lamp which can be tuned to vary from 1300 to 2200°C. Using very high shutter speed and small aperture, the high-speed camera successfully captured the tungsten ribbon without image saturation at the full temperature scale. Tests have been carried out at different temperature and camera settings. The sensitivity and errors have been analysed, and experiment results demonstrate the potential of using very high shutter speed is available for measuring the temperature even beyond 2200°C. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
47. A modified COMS plaque for iris melanoma
- Author
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Daniel J. Scanderbeg, Deepta Vasudev, Roger K. Rice, Michael Goldbaum, and Arno J. Mundt
- Subjects
brachytherapy ,COMS ,eye plaque ,iris melanoma ,Medicine - Abstract
Melanoma of the iris is a rare condition compared to posterior ocular tumors and in this case report we presenta 51-year-old female patient with diffuse iris melanoma. Traditional COMS (Collaborative Ocular Melanoma Study)plaques are used at our institution for radiation therapy, so a novel modification of the traditional plaque was requiredto allow better conformance with placement on the cornea. The usual silastic insert was machined to dimensions incompliance with the cornea, placed without incident, and treatment delivered with excellent patient tolerance of themodified plaque.
- Published
- 2011
48. 보급형 천리안 위성 기상정보 수신시스템을 위한 FPGA 기반 기상정보 데이터 수신회로 개발
- Author
-
류상문
- Abstract
COMS(Communication, Ocean and Meteorological Satellite), the first Korean geostationary meteorological satellite, provides free meteorological information through HRIT/LRIT(High/Low Rate Information Transmission) service. This work presents the development of data receiver circuit that is essential to the implementation of a low-cost meteorological information receiver system. The data receiver circuit processes the data units according to the specification of physical layer and data link layer of HRIT/LRIT service. For this purpose, the circuit consists of a Viterbi decoder, a sync. word detector, a derandomizer, a Reed-Solomon decoder and so on. The circuit also supports PCI express interface to pass the information data on to the host PC. The circuit was implemented on an FPGA(field programmable gate array) and its function was verified through simulations and hardware implementation. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
49. Analysis of the angle-only orbit determination for optical tracking strategy of Korea GEO satellite, COMS.
- Author
-
Choi, Jin, Jo, Jung Hyun, Roh, Kyoung-Min, Son, Ju-Young, Kim, Myung-Jin, Choi, Young-Jun, Yim, Hong-Suh, Moon, Hong-Kyu, Kim, Bang-Yeop, Park, Jang-Hyun, and Pavlis, Erricos C.
- Subjects
- *
ORBIT determination , *GEOSTATIONARY satellites , *EARTH'S orbit , *OPTICAL resolution , *RADAR - Abstract
Increasing numbers of Geostationary Earth Orbit satellites have led to the requirement of accurate station keeping and precise orbit prediction to avoid collision between satellites. In the case of ground-based optical observation, angular resolution is better than other tracking systems, such as radar systems; however, the observation time of optical observation is limited by weather or lighting conditions. To develop an effective optical observation strategy, the optical observation campaign from January to February 2014 for Communication, Ocean and Meteorological Satellite (COMS) was conducted. Because COMS is a controlled satellite with station keeping manoeuvres performed twice a week, the observation results for 1- and 2-day observations were analysed. Sparse and sporadic cases for the sequential observation of multiple satellites and a dense case for the intensive observation of specific targets were assumed for the experiments. In the 1-day arc observation experiment, the estimated orbits for dense observation cases over 10% of the orbital period showed that the maximum difference was less than 40 km (station keeping area) for 7-day propagation compared to the estimation result using the whole 1-day measurement. For the 2-day arc observation, the orbit estimation difference could be maintained within 2 km using a more frequent observation than the 1-h interval for 13 h that was used in the sparse case. Additionally, the longitudinal and latitudinal positions via the estimation result using the optical observation were compared with the Two-Line Elements (TLEs) and operator’s data. Through this study, an adequate optical tracking strategy was studied, and the possibility of cooperation with other systems was also validated. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
50. Evaluation of geostationary satellite (COMS) based Priestley–Taylor evapotranspiration.
- Author
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Baik, Jongjin and Choi, Minha
- Subjects
- *
GEOSTATIONARY satellites , *WATER use , *IRRIGATION farming , *EVAPOTRANSPIRATION measurement , *ATMOSPHERE - Abstract
Effective water use in the irrigated agriculture requires an accurate estimation of evapotranspiration (ET) to understand the interaction between land surface and the atmosphere. The operationally available polar orbit satellite datasets with low temporal resolutions have long been utilized for the estimation of ET from field to regional scale. However, geostationary satellites, which are continuously measuring several factors related to land surface and the atmosphere over large regional scales, have high temporal resolution compared to polar orbit satellites. Thus, in this study, we present a framework for estimating potential ET at three different temporal scales (instantaneous, 3-h and daily) using the Priestley–Taylor (ET PT ) method with a new geostationary satellite, the Communication, Ocean, and Meteorological Satellite (COMS) dataset. The derived ET PT estimates were compared with ground based flux tower [Cheongmi (CFC) and Sulma (SMC)] measurements, with ET PT calculated from MODerate Resolution Imaging Spectroradiometer (MODIS) and with ET PT calculated from Global Land Data Assimilation System (GLDAS) datasets during the growing seasons of 2011. The GLDAS ET PT were significantly overestimated compared to the flux tower ET PT (bias of 147.92 and 169.69 W m −2 at 3-h time scale and bias of 2.64 and 3.37 mm day −1 at daily time scale for SMC and CFC, respectively), while the COMS and MODIS ET PT were slightly underestimated (bias ranged from −15.31 to −55.65 W m −2 at instantaneous time scale and bias ranged from −0.04 to −1.03 mm day −1 at daily time scale for SMC and CFC, respectively). Based on the results, the COMS estimated ET PT was slightly more accurate than MODIS ET PT in comparison with the flux tower ET PT , yielding the index of agreement (IOA) between ∼0.89 and 0.96 for all time scale. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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