• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.591-601
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• 2018

This paper discusses methods to effectively operates and evaluates an infrastructure system for lane-level positioning based on satellite navigation. The lane-level positioning infrastructure provides correction information on range measurements with integrity information on the correction to a user with a single frequency (cheap) satellite navigation receiver in order to perform lane-level positioning and integrity monitoring on the position estimate. The architecture and configuration of the lane-level positioning system are described from the systematic level in order to provide a comprehensive insight of the system. The operation/evaluation system for the integrated infrastructure is then presented. The evaluation results of the real implemented system are provided. Based on the results, we discuss requirements to increase the system stability from the operation perspective.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.525-533
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• 2008

Global circulation models (GCMs) have been used to study impact of climate change on water resources for hydrologic models as inputs. Recently, regional circulation models (RCMs) have been used widely for climate change study, but the RCMs have been rarely used in the climate change impacts on water resources in Korea. Therefore, this study is intended to use a set of climate scenarios derived by RegCM3 RCM ($27km{\times}27km$), which is operated by Korea Meteorological Administration. To begin with, the RCM precipitation data surrounding major rainfall stations are extracted to assess validation of the scenarios in terms of reproducing low frequency behavior. A comprehensive comparison between observation and precipitation scenario is performed through statistical analysis, wavelet transform analysis and EOF analysis. Overall analysis confirmed that the precipitation data driven by RegCM3 shows capabilities in simulating hydrological low frequency behavior and reproducing spatio-temporal patterns. However, it is found that spatio-temporal patterns are slightly biased and amplitudes (variances) from the RCMs precipitation tend to be lower than the observations. Therefore, a bias correction scheme to correct the systematic bias needs to be considered in case the RCMs are applied to water resources assessment under climate change.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.75-83
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• 1998

This study was done to recognize the importance of errors in measurements of cephalometric radiograph and to find the anatomical structures those need special care to select as a reference points through the detection of the systematic errors and estimation of random errors. For this purose, 100 cephalometric radiographs were prepared by usual manner and 61 reference points, and 130 measurement variables were established. Measurement errors were detected and estimated by the comparison of the 25 randomly-selected samples for repeated measurements with the main sample. The following results were obtained : 1. In comparison of the repeated measurements, there were statistical significant differences in 24 variables which were 18.4% of 130 total variables. 2. The frequency of the difference in identification of the reference points between the repeated measurements was very high in the root apex of upper incisor(as), the most posterior wall of maxilla(tu), soft tissue nasion(n'), soft tissue frontal eminence(ft), and ad3 in airway. 3. After correction of reference points marking until the level of below 5% significance, the range of random errors were from 0.67 to 1.71 degree or mm. 4. The variable shown the largest random error was the interincisal angle(ILs-ILi). 5. Measurement errors were mainly caused by the lack of precision in anatomic definitions and obscure radiographic image. From the above results, the author could find the high possibility of errors in cephalometric measurements and from this point, we should include error analysis in all the studies concerning measurments. In is essential to have a concept of error analysis not only for the investigator but also for a reader of other articles.

• Radiation Oncology Journal
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• v.36 no.1
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• pp.54-62
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• 2018

Purpose: To investigate set-up errors, suggest the adequate planning target volume (PTV) margin and image-guided radiotherapy frequency in head and neck (H&N) cancer treated with intensity-modulated radiotherapy (IMRT) assessed by kV cone-beam computed tomography (CBCT). Methods: We analyzed 360 CBCTs in 60 patients with H&N cancer treated with IMRT. The target delineation was contoured according to ICRU62. PTVs were generated by adding a 3-5 mm margin in all directions to the respective clinical target volumes. The kV CBCT images were obtained at first three days of irradiation and weekly thereafter. The overall mean displacement, range, systematic (${\Sigma}$) and random (${\sigma}$) errors were calculated. Adequate PTV margins were calculated according to the van Herk formula ($2.5{\Sigma}+0.7r$). Results: The mean of set-up errors was less than 2 mm in any direction. The overall frequency of set-up displacements greater than 3 mm was 3.9% in medial-lateral (ML) direction, 8% in superior-inferior (SI) direction, and 15.5% in anterior-posterior (AP) direction. The range of translations shifts was 0-9 mm in ML direction, 0-5 mm in SI direction and 0-10 mm in AP direction, respectively. After systematic set-up errors correction, the adequate margin to overcome the problem of set-up errors was found to be less than 3 mm. Conclusion: Image-guided kV CBCT was effective for the evaluation of set-up accuracy in H&N cancer. The kV CBCT at first three fractions and followed-by weekly appears adequate for reducing significantly set-up errors in H&N cancer treated with IMRT technique. Finally, 3-5 mm PTV margins appear adequate and safe to overcome the problem of set-up errors.

• Journal of Korea Water Resources Association
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• v.42 no.10
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• pp.773-783
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• 2009

The effects of rainfall input uncertainty on predictions of stream flow are studied based extended GLUE (Generalized Likelihood Uncertainty Estimation) approach. The uncertainty in the rainfall data is implemented by systematic/non-systematic rainfall measurement analysis in Weida catchment, Germany. PDM (Probability Distribution Model) rainfall runoff model is selected for hydrological representation of the catchment. Using general correction procedure and DUE(Data Uncertainty Engine), feasible rainfall time series are generated. These series are applied to PDM in MC(Monte Carlo) and GLUE method; Posterior distributions of the model parameters are examined and behavioural model parameters are selected for simplified GLUE prediction of stream flow. All predictions are combined to develop ensemble prediction and 90 percentile of ensemble prediction, which are used to show the effects of uncertainty sources of input data and model parameters. The results show acceptable performances in all flow regime, except underestimation of the peak flows. These results are not definite proof of the effects of rainfall uncertainty on parameter estimation; however, extended GLUE approach in this study is a potential method which can include major uncertainty in the rainfall-runoff modelling.

• Journal of Power Electronics
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• v.15 no.3
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• pp.621-633
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• 2015

This paper proposes the analysis and design of a DC-side symmetrical zero-current-switching (ZCS) Class-D current-source driven resonant rectifier to improve the low power-factor and high line current harmonic distortion of lighting applications. An analysis of the junction capacitance effect of Class-D ZCS rectifier diodes, which has a significant impact on line current harmonic distortion, is discussed in this paper. The design procedure is based on the principle of the symmetrical Class-D ZCS rectifier, which ensures more accurate results and provides a more systematic and feasible analysis methodology. Improvement in the power quality is achieved by using the output characteristics of the DC-side Class-D ZCS rectifier, which is inserted between the front-end bridge-rectifier and the bulk-filter capacitor. By using this symmetrical topology, the conduction angle of the bridge-rectifier diode current is increased and the low line harmonic distortion and power-factor near unity were naturally achieved. The peak and ripple values of the line current are also reduced, which allows for a reduced filter-inductor volume of the electromagnetic interference (EMI) filter. In addition, low-cost standard-recovery diodes can be employed as a bridge-rectifier. The validity of the theoretical analysis is confirmed by simulation and experimental results.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.56.1-56.1
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• 2013

Supernovae type Ia (SNe Ia) cosmology is providing the only direct evidence for the presence of dark energy. This result is based on the assumption that the look-back time evolution of SNe Ia luminosity, after light-curve shape correction, would be negligible. However, the most recent compilation of SNe Ia data shows systematic difference in the Hubble residual (HR) between the E and Sd/Irr galaxies, indicating that the light-curve fitters used by the SNe Ia community cannot quite correct for a large portion of the population age effect. In order to investigate this possibility more directly, we have obtained low-resolution spectra for 30 nearby early-type host galaxies. This data set is used to estimate the luminosity-weighted mean ages and metallicities of host galaxies by employing the population synthesis models. We found an interesting trend between the host galaxy age and HR, in the sense that younger galaxies have positive residuals (i.e., light-curve corrected SNe Ia luminosity is fainter). This result is rather independent of the choice of the population synthesis models employed. Taken at face value, this age (evolution) effect can mimic a large fraction of the HR used in the discovery of the dark energy. This result is significant at 1.4 - 3 sigma levels, depending on the light curve fitters adopted, and further observations and analyses are certainly required to confirm the trend reported here.

• Journal of Korean Society of Disaster and Security
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• v.9 no.1
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• pp.39-45
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• 2016

The disasters in Korea, such as the Sewol Ferry Ship sinking disaster has had problems related to the medical response system, with the problems of emergency medical support team in the site, the cooperation between medical staff and fire department officer at disaster site, field medical support and hospital acceptance of the wounded in trouble, the lack of specific systematic medical response manual. Therefore, from May 2014, when the disaster emergency information center in Central Emergency Medical Center starts, collection, modification and education of scattered preexisting disaster emergency medical manual had appeared as important issues. So, it was necessary to develop the early medical response system to disaster. The correction planning of disaster emergency medical response system by Central Emergency Medical Center included quick response system with the fast medical team operation, but the practical application was not enough. So the researcher and his team developed the first Korean disaster emergency medical response manual and the process of development was documented and arranged with the application by education and training.

• Journal of Korean society of Dental Hygiene
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• v.10 no.3
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• pp.503-512
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• 2010

Objectives : In this study, in order to provide basic data for more efficient and systematic clinical practice training by recognizing the need of effective and standardized operation of clinical practice accomplished in clinical fields belonging to the curriculum of dental hygiene department, grasping, investigating, and analyzing satisfaction degree of the clinical practice through student's frequency of observation practice and performance practice. Methods : A survey was conducted against 208 students in the 3rd grade of 4 dental hygiene departments located in Jeonbuk province. Results : As results, it was found that for the observation practice frequency according to clinical practice term by universities, the basic clinical practice was higher in A, B, and D university and that the correction and practice was higher in D university. For the performance practice frequency, it was found that basic care practice was higher in B and D university, oral medicine practice, preventive dentistry practice, and periodontal practice were higher in A and C university, pediatric dentistry practice was higher in B and C university, prosthetic dentistry practice was higher in A, B, and C university, and oral surgery practice was higher in B university. It was identified that satisfaction was higher in the basic care practice, the preventive dentistry practice, and the periodontal practice in the range of clinical practice, and the A and C university receiving higher score in the performance practice frequency got higher score in the oral medicine practice, the preventive dentistry practice, and the periodontal practice. Conclusions : As the basic care practice items in the clinical practice area which got relatively higher score in observation practice, performance practice, and satisfaction degree of the dental hygiene trainee are basic and essential works that they will perform the most frequently, it is considered that integrated clinical practice training including the intramural practice course is required.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.21-32
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• 1999

Mapping and precise point determination by photogrammetry have been shown to be an economic solution. But control points are necessary to determine the exterior orientation parameters. Although the number of required control points has been reduced based on extended bundle adjustment and reinforced cross-strip, the ground survey is a significant factor of whole expenses in photogrammetry. The status of GPS-photogrammetry with kinematic DGPS-positioning to overcome this disadvantages, is now steadly progressive since the first possibility has been proved. The completed satellite configuration, powerful receiver function and upgraded software for kinematic DGPS-positioning have extensively improved the accuracy of combined bundle adjustment. So the research for the operational use of GPS-photogrammetry is absolutely necessary. The presented test field was designed for identification of subsidences in a coal mining area, flown with 60％ sidelap and cross strips. Just with 6 control points and combined block adjustment instead of the traditionally used 21 horizontal and 81 vertical control points the same ground accuracy has been reached. The accuracy of kinematic GPS-positioning and combined block adjustment was independent upon the distance of the ground reference station. It also has been showed that the special model for the systematic error correction in the combined block adjustment.