• Proceedings of the KSRS Conference
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• v.1
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• pp.150-152
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• 2006

The DISCOVER Project (${\underline{D}}istributed$ ${\underline{I}}nformation$ ${\underline{S}}ervices$ for ${\underline{C}}limate$ and ${\underline{O}}cean$ products and ${\underline{V}}isualizations$ for ${\underline{E}}arth$ ${\underline{R}}esearch$) is a NASA funded Earth Science REASoN project that strives to provide highly accurate, carefully calibrated, long-term climate data records and near-real-time ocean products suitable for the most demanding Earth research applications via easy-to-use display and data access tools. A key element of DISCOVER is the merging of data from the multiple sensors on multiple platforms into geophysical data sets consistent in both time and space. The project is a follow-on to the SSM/I Pathfinder and Passive Microwave ESIP projects which pioneered the simultaneous retrieval of sea surface temperature, surface wind speed, columnar water vapor, cloud liquid water content, and rain rate from SSM/I and TMI observations. The ocean products available through DISCOVER are derived from multi-sensor observations combined into daily products and a consistent multi-decadal climate time series. The DISCOVER team has a strong track record in identifying and removing unexpected sources of systematic error in radiometric measurements, including misspecification of SSM/I pointing geometry, the slightly emissive TMI antenna, and problems with the hot calibration source on AMSR-E. This in-depth experience with inter-calibration is absolutely essential for achieving our objective of merging multi-sensor observations into consistent data sets. Extreme care in satellite inter-calibration and commonality of geophysical algorithms is applied to all sensors. This presentation will introduce the DISCOVER products currently available from the web site, http://www.discover-earth.org and provide examples of the scientific application of both the diurnally corrected optimally interpolated global sea surface temperature product and the 4x-daily global microwave water vapor product.

• International Journal of Control, Automation, and Systems
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• v.4 no.4
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• pp.414-427
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• 2006

This paper presents an adaptive feedback linearization control scheme for induction motors with simultaneous variation of rotor and stator resistances. Two typical modeling techniques, rotor flux model and stator flux model, have been developed and successfully applied to the controller design and adaptive observer design, respectively. By using stator fluxes as states, over-parametrization in adaptive control can be prevented and control strategy can be developed without the need of nonlinear transformation. It also decrease the relative degree for the flux modulus by one, thereby, yielding, a simple control algorithm. However, when this method is used for flux observer, it cannot guarantee the convergence of flux. Similarly, the rotor flux model may be appropriate for observers, but it is not so for adaptive controllers. In addition, if these two existing methods are merged into overall adaptive control system, it brings about structural complexies. In this paper, we did not use these two modeling methods, and opted for the airgap flux model which takes on only the positive aspects of the existing rotor flux model and stator flux model and prevents structural complexity from occuring. Through theoretical analysis by using Lyapunov's direct method, simulations, and actual experiments, it is shown that stator and rotor resistances converge to their actual values, flux is well estimated, and torque and flux are controlled independently with the measurements of rotor speed, stator currents, and stator voltages. These results were achieved under the persistent excitation condition, which is shown to hold in the simulation.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.48.3-49
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• 2016

We have five different types of observation modes with regard to the Deep Ecliptic Patrol of the Southern Sky (DEEP-South); Opposition Census (OC) for targeted photometry, Sweet Spot Survey (S1) for discovery and orbit characterization of Atens and Atiras, Ecliptic Survey (S2) for asteroid family studies and comet census, NEOWISE follow-up (NW) for near simultaneous albedo measurements in the visible bands, and Target of Opportunity (TO) observation for follow-up either for unpredictable events or targets of special interests. Different exposures with such different modes result in a wide range of background noise level, the number of background stars and the mover's projected speed in each image. The Moving Object Detection Program (MODP) utilizes multiple mosaic images being taken for the same target fields at different epochs at the three KMTNet sites. MODP employs existing software packages such as SExtractor (Source-Extractor) and SCAMP (Software for Calibrating Astrometry and Photometry); SExtractor generates object catalogs, while SCAMP conducts precision astrometric calibration, then MODP determines if a point source is moving. This package creates animated stamp images for visual inspection with MPC reports, the latter for checking whether an object is known or unknown. We evaluate the astrometric accuracy and efficiency of MODP using the year one dataset obtained from DEEP-South operations.

• The korean journal of orthodontics
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• v.48 no.1
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• pp.30-38
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• 2018

Objective: The purpose of this study was to investigate factors influencing the success rate of orthodontic microimplants (OMIs) using panoramic radiographs (PRs). Methods: We examined 160 OMIs inserted bilaterally in the maxillary buccal alveolar bone between the second premolars and first molars of 80 patients (51 women, 29 men; mean age, $18.0{\pm}6.1years$) undergoing treatment for malocclusion. The angulation and position of OMIs, as well as other parameters, were measured on PRs. The correlation between each measurement and the OMI success rate was then evaluated. Results: The overall success rate was 85.0% (136/160). Age was found to be a significant predictor of implant success (p < 0.05), while sex, side of placement, extraction, and position of the OMI tip were not significant predictors (p > 0.05). The highest success rate was observed for OMIs with tips positioned on the interradicular midline (IRML; central position). Univariate analyses revealed that the OMI success rate significantly increased with an increase in the OMI length and placement height of OMI (p = 0.001). However, in simultaneous analyses, only length remained significant (p = 0.027). Root proximity, distance between the OMI tip and IRML, interradicular distance, alveolar crest width, distance between the OMI head and IRML, and placement angle were not factors for success. Correlations between the placement angle and all other measurements except root proximity were statistically significant (p < 0.05). Conclusions: Our findings suggest that OMIs positioned more apically with a lesser angulation, as observed on PRs, exhibit high success rates.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.401-408
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• 2005

Recently shield TBM tunnellings are being applied to subway construction in Korean cities. Generally these kinds of tunnellings have the problems in the stability of ground such as subsidence because urban subway is constructed in the shallow depth. A sinkhole occurred on the road just above the tunnel during tunneling in Kwangju, so a survey for upper layer of the tunnel was needed. But conventional Ground Probing Radar can't be applicable due to the presence of steel-mesh screen in the shield segment, so no existent geophysical method is applicable in this site. Because the outer surface of each shield segment is electrically insulated, dipole-dipole resistivity method which is popular in engineering site investigation, was tried to this survey for the first time. Specially manufactured flexible ring-type electrodes were installed into the grouting holes at an interval of 2.4 m on the ceiling. The K-Ohm II system which has been developed by KIGAM and tested successfully in many sites, was used in this site. The system consists of 1000Volt-1Ampere constant-current transmitter, optically isolated 24 bit sigma-delta A/D conversion receiver - maximum 12 channel simultaneous measurements, and graphical automatic acquisition software for easy data quality check in real time. Borehole camera logging with circular white LED lighting was also done to investigate the state of the layer. Measured resistivity data lack of some stations due to failing opening lids of holes, shows general high-low trend well. The dipole-dipole resistivity inversion results discriminate (1) one approximately 4 meter diameter cavity (grouted but incompletely hardened, so low resistivity - less than $30{\Omega}m$), (2) weak zone (100-200${\Omega}m$), and (3) hard zone (high resistivity - more than 1000${\Omega}m$) very well for the distance of 320 meters. The 2-D inversion neglects slight absolute 3-D effect, but we can get satisfactory and useful information. Acquired resistivity section and video tapes by borehole camera logging will be reserved and reused if some problem occurs in this site in the future.

• Spatial Information Research
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• v.7 no.1
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• pp.63-79
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• 1999

In this research, the operational principle and the internal algorithm of theodolite measuring systems are studied and coded for a new software, and the feasibility of the laser system for the above mentioned usage is studied by simulation set-up of the system in the laboratory environment, and for the theodolite system modules for the communication between theodolite and computer is implemented, the data collection and storage, the simultaneous photogrammetric ' bundle ' adjustment for the theodolite position and the target points are coded, compiled and tested. for the simulation set-up of the laser system extensive studies on laser sources and laser detectors are performed, the system composition for the system simulation in the laboratory environment is studied and implemented, and the beam fluctuation due to the environmental changes in the course of the laser beam, such as changes in current of wind or in temperature is experimented. According to Experiment on the Source of 17 meters interval and the Detector, Laser beam is almost doesn't depend on air How, but it is effected by variations of temperature and light. Selecting cloudy day and time without change of temperature, it was realized that it is possible to perform deformation measurement more than approximately 2mm precision.precision.

• Ocean and Polar Research
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• v.26 no.3
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• pp.489-499
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• 2004

The climatological characteristics of the polar ionospheric currents obtained from the simultaneous observations of the ionospheric electric field and conductivity are examined. For this purpose, 43 and 109 days of measurements from the Chatanika and Sondrestrom incoherent scatter radars are utilized respectively. The ionospheric current density is compared with the corresponding ground magnetic disturbance. Several interesting characteristics about the polar ionosphere are apparent from this study: (1) The sun determines largely the conductance over the Sondrestrom radar, while the nighttime conductance distribution over the Chatanika radar is significantly affected by auroral precipitation. (2) The regions of the maximum N-S electric field over the Chatanika radar are located approximately at the dawn and dusk sectors, while they tend to shift towards dayside over the Sondrestrom radar. The N-S component over Son-drestrom is slightly stronger than Chatanika. However, the E-W component over Chatanika is negligible compared to that of Sondrestrom. (3) The E-W ionospheric current flows dominantly in the night hemisphere over Chatanika, while it flows in the sunlit hemisphere over Sondrestrom. The N-S current over Chatanika flows prominently in the dawn and dusk sectors, while a strong southward current flows in the prenoon sector over Sondrestrom. (4) The assumption of infinite sheet current approximation is far from realistic, underestimating the current density by a factor of 2 or more. It is particularly serious for the higher latitude region. (5) The correlation between ${\Delta}H\;and\;J_E$ is higher than the one between ${\Delta}D\;and\;J_N$, indicating that field-aligned current affects ${\Delta}D$significantly.

• Clinical and Experimental Pediatrics
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• v.60 no.2
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• pp.45-49
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• 2017

Purpose: Serum level of 25-hydroxyvitamin D (25-OHD) is considered as the most appropriate marker of vitamin D status. However, only a few studies have investigated the relationship between 25-OHD and parathyroid hormone (PTH) in children. To this end, this study was aimed at evaluating the lowest 25-OHD level that suppresses the production of parathyroid hormone in children. Methods: A retrospective record review was performed for children aged 0.2 to 18 years (n=193; 106 boys and 87 girls) who underwent simultaneous measurements of serum 25-OHD and PTH levels between January 2010 and June 2014. Results: The inflection point of serum 25-OHD level for maximal suppression of PTH was at 18.0 ng/mL (95% confidence interval, 14.3-21.7 ng/mL). The median PTH level of the children with 25-OHD levels of <18.0 ng/mL was higher than that of children with 25-OHD levels ${\geq}$ 18.0 ng/mL (P<0.0001). The median calcium level of children with 25-OHD levels<18.0 ng/mL was lower than that of children with 25-OHD levels${\geq}18.0ng/mL$ (P=0.0001). The frequency of hyperparathyroidism was higher in the children with 25-OHD levels<18.0 ng/mL than in the children with 25-OHD levels${\geq}18.0ng/mL$ (P<0.0001). Hypocalcemia was more prevalent in the children with 25-OHD levels<18.0 ng/mL than in the children with 25-OHD levels${\geq}18.0ng/mL$ (P<0.0001). Conclusion: These data suggest that a vitamin D level of 18.0 ng/mL could be the criterion for 25-OHD deficiency in children at the inflection point of the maximal suppression of PTH.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.4
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• pp.257-263
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• 2018

Purpose: Studies on the physiology of the transposed stomach as an esophageal substitute in the form of a gastric pull-up or a gastric tube in children are limited. We conducted a study of motility and the pH of gastric esophageal substitutes using manometry and 24-hour pH measurements in 10 such patients. Methods: Manometry and 24 hour pH studies were performed on 10 children aged 24 to 55 months who had undergone gastric esophageal replacement. Results: Six gastric tubes (4, isoperistaltic; 2, reverse gastric tubes) and 4 gastric pull-ups were studied. Two gastric tubes and 4 gastric pull-ups were transhiatal. Four gastric tubes were retrosternal. The mean of the lowest pH at the midpoint of the substitute was 4.0 (range, 2.8-5.0) and in the stomach remaining below the diaphragm was 3.3 (range, 1.9-4.2). In both types of substitute, the difference between the peak and the nadir pH recorded in the intra-thoracic and the sub-diaphragmatic portion of the stomach was statistically significant (p<0.05), with the pH in the portion below the diaphragm being lower. The lowest pH values in the substitute and in the remnant stomach were noted mainly in the evening hours whereas the highest pH was noted mainly in the morning hours. All the cases showed a simultaneous rise in the intra-cavitatory pressure along the substitute while swallowing. Conclusion: The study suggested a normal gastric circadian rhythm in the gastric esophageal substitute. Mass contractions occurred in response to swallowing. The substitute may be able to effectively clear contents.

• Archives of Craniofacial Surgery
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• v.20 no.6
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• pp.361-369
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• 2019

Background: Trauma is one of the most common causes of enophthalmos, and post-traumatic enophthalmos primarily results from an increased volume of the bony orbit. We achieved good long-term results by simultaneously using an anatomical absorbable implant and iliac bone graft to correct post-traumatic enophthalmos. Methods: From January 2012 to December 2016, we performed operations on seven patients with post-traumatic enophthalmos. In all seven cases, reduction surgery for the initial trauma was performed at our hospital. Hertel exophthalmometry, clinical photography, three-dimensional computed tomography (3D-CT), and orbital volume measurements using software to calculate the specific volume captured on 3D-CT (ITK-SNAP, Insight Toolkit-SNAP) were performed preoperatively and postoperatively. Results: Patients were evaluated based on exophthalmometry, clinical photographs, 3D-CT, and orbital volume measured by the ITK-SNAP program at 5 days and 1 year postoperatively, and all factors improved significantly compared with the preoperative baseline. Complications such as hematoma or extraocular muscle limitation were absent, and the corrected orbital volume was well maintained at the 1-year follow-up visit. Conclusion: We present a method to correct enophthalmos by reconstructing the orbital wall using an anatomical absorbable implant and a simultaneous autologous iliac bone graft. All cases showed satisfactory results for enophthalmos correction. We suggest this method as a good option for the correction of post-traumatic enophthalmos.