• Nuclear Engineering and Technology
• /
• v.49 no.5
• /
• pp.1100-1108
• /
• 2017

A thermal-hydraulic system code is an essential tool for the design and safety analysis of a nuclear power plant, and its accuracy quantification is very important for the code assessment and applications. The fast Fourier transform-based method (FFTBM) by signal mirroring (FFTBM-SM) has been used to quantify the accuracy of a system code by using a comparison of the experimental data and the calculated results. The method is an improved version of the FFTBM, and it is known that the FFTBM-SM judges the code accuracy in a more consistent and unbiased way. However, in some applications, unrealistic results have been obtained. In this study, it was found that accuracy quantification by FFTBM-SM is dependent on the frequency spectrum of the fast Fourier transform of experimental and error signals. The primary objective of this study is to reduce the frequency dependency of FFTBM-SM evaluation. For this, it was proposed to reduce the cut off frequency, which was introduced to cut off spurious contributions, in FFTBM-SM. A method to determine an appropriate cut off frequency was also proposed. The FFTBM-SM with the modified cut off frequency showed a significant improvement of the accuracy quantification.

• The Journal of Advanced Prosthodontics
• /
• v.14 no.4
• /
• pp.236-249
• /
• 2022

PURPOSE. The present study compared the accuracy between digital and conventional implant impressions. MATERIALS AND METHODS. The experimental models were divided into six groups depending on the implant location and the scanning span. Digital impressions were captured using the intraoral optical scanner TRIOS (3Shape, Copenhagen, Denmark). Conventional impressions were taken with the monophase impression material based on addition-cured silicones, Honigum-Mono (DMG, Hamburg, Germany). A high-precision laboratory scanner D900 (3Shape, Copenhagen, Denmark) was used to obtain digital data of resin models and stone casts. Surface tessellation language (STL) datasets from scanner were imported into the analysis software Geomagic Qualify 14 (3D Systems, Rock Hill, SC, USA), and scan body deviations were determined through two-dimensional and three-dimensional analyses. Each scan body was measured five times. The Sidak t test was used to analyze the experimental data. RESULTS. Implant position and scanning distance affected the impression accuracy. For a unilateral arch implant and the mandible models with two implants, no significant difference was observed in the accuracy between the digital and conventional implant impressions on scan bodies; however, the corresponding differences for trans-arch implants and mandible with six implants were extremely significant (P<.001). CONCLUSION. For short-span scanning, the accuracy of digital and conventional implant impressions did not differ significantly. For long-span scanning, the precision of digital impressions was significantly inferior to that of the traditional impressions.

• IEIE Transactions on Smart Processing and Computing
• /
• v.5 no.6
• /
• pp.390-394
• /
• 2016

This paper presents a new comparison method for haze-removal algorithms in next-generation automotive systems. Compared to previous peak signal-to-noise ratio-based comparisons, which measure similarity, the proposed modulation transfer function-based method checks sharpness to select a more suitable haze-removal algorithm for lane detection. Among the practical filtering schemes used for a haze-removal algorithm, experimental results show that Gaussian filtering effectively preserves the sharpness of road images, enhancing lane detection accuracy.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.11a
• /
• pp.535-538
• /
• 2004

Recently, Ministry of Government Administration and Home Affairs and Local Governments drafted plan to digitize cadastral maps for making effective land management and development. Cadastral map have difference in comparison with actual area's boundary since they used long time and continuously. In this study, verification of accuracy has concerned in comparison with cadastral map and IKONOS satellite image which has geometrical correction.

• The Journal of Korean Academy of Prosthodontics
• /
• v.59 no.3
• /
• pp.370-378
• /
• 2021

Purpose. The purpose of this study was to evaluate the currently published literatures investigating the accuracy of computer-aided design and computer-aided manufacturing removable partial denture (CAD-CAM RPD) framework with different manufacturing techniques and methods. Materials and methods. A comprehensive search for literatures was conducted in PubMed database using specific keywords with the patient, intervention, comparison, and outcome (PICO) question, "Is there a difference in accuracy of RPD frameworks manufactured using digital workflow according to the manufacturing process and methods?" Results. A total of 7 articles were selected. Two studies compared intraoral scanning and laboratory scanning for RPD frameworks and had heterogenous results. In the studies using different manufacturing process, RPD frameworks had clinically acceptable accuracy in both subtractive and additive manufacturing. Polyetheretherketone (PEEK)-milled RPD frameworks showed higher fit accuracy than traditionally casted or 3D printed RPDs. Direct milling method showed a higher accuracy than indirect milling method. However, in rapid prototyping, indirect method showed higher accuracy than direct method. Conclusion. The RPD frameworks fabricated using CAD-CAM technology showed a clinically acceptable level of accuracy regardless of manufacturing process or techniques. Consistent results have not been reported regarding the digital impression methods, which were intra oral scanning or laboratory scanning, and further studies are needed.

• Journal of Ecology and Environment
• /
• v.35 no.2
• /
• pp.91-98
• /
• 2012

This study was performed in order to suggest the possibility of tree species classification using high-resolution QuickBird-2 images spectral characteristics comparison(digital numbers [DNs]) of tree species, tree species classification, and accuracy verification. In October 2010, the tree species of three conifers and eight broad-leaved trees were examined in the areas studied. The spectral characteristics of each species were observed, and the study area was classified by image classification. The results were as follows: Panchromatic and multi-spectral band 4 was found to be useful for tree species classification. DNs values of conifers were lower than broad-leaved trees. Vegetation indices such as normalized difference vegetation index (NDVI), soil brightness index (SBI), green vegetation index (GVI) and Biband showed similar patterns to band 4 and panchromatic (PAN); Tukey's multiple comparison test was significant among tree species. However, tree species within the same genus, such as $Pinus$ $densiflora-P.$ $rigida$ and $Quercus$ $mongolica-Q.$ $serrata$, showed similar DNs patterns and, therefore, supervised classification results were difficult to distinguish within the same genus; Random selection of validation pixels showed an overall classification accuracy of 74.1% and Kappa coefficient was 70.6%. The classification accuracy of $Pterocarya$ $stenoptera$, 89.5%, was found to be the highest. The classification accuracy of broad-leaved trees was lower than expected, ranging from 47.9% to 88.9%. $P.$ $densiflora-P.$ $rigida$ and $Q.$ $mongolica-Q.$ $serrata$ were classified as the same species because they did not show significant differences in terms of spectral patterns.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.12
• /
• pp.5001-5004
• /
• 2015

The Reid colposcopic index (RCI) helps physicians for interpret the results of colposcopic examination. To compare the accuracy of RCI in colposcopic evaluation between general and oncologic gynecologists, this prospective trial was conducted by invited women over 20 years of age who were scheduled for a colposcopy at Chiang Mai University Hospital between August, 2008 and May, 2014 to participate. Pregnant patients or those having a history of hysterectomy or conization were excluded. During the colposcopy, all patients were simultaneously evaluated by general and oncologic gynecologists utilizing the RCI. Further management with either a biopsy or LEEP in each patient was dependent on the decision of the attending oncologic gynecologist. The accuracy of the RCI in diagnosing HSIL or more was calculated by the comparison with the final histology. Finally, 135 patients were recruited into this study. The sensitivity, specificity, PPV, NPV, and accuracy of RCI in diagnosing HSIL or more in general gynecologists were 45.2%, 80.7%, 41.1%, 83.2% and 72.6% while in the oncologic gynecologists were 51.6%, 85.6%, 51.6%, 85.6% and 77.8%, respectively. The difference in accuracy between evaluator groups was not significant (p-value=0.28). Of 3 patients with invasive cervical cancer, all were undetected by the general gynecologists using RCI while only 1 invasive cervical cancer was missed via RCI by the oncologic gynecologists. We conclude that RCI could be used by general gynecologists in provincial hospitals with major concerns about missing invasive cervical cancer. A short training period regarding colposcopy might help to resolve this problem.

• The Journal of Advanced Prosthodontics
• /
• v.14 no.3
• /
• pp.150-161
• /
• 2022

PURPOSE. The purpose of the study was to assess the influence of build orientations and density of support structures on the trueness of the 3D printed removable partial denture (RPD) frameworks. MATERIALS AND METHODS. A maxillary Kennedy class III and mandibular class I casts were 3D scanned and used to design and produce two 3D virtual models of RPD frameworks. Using digital light processing (DLP) 3D printing, 47 RPD frameworks were fabricated at 3 different build orientations (100, 135 and 150-degree angles) and 2 support structure densities. All frameworks were scanned and 3D compared to the original virtual RPD models by metrology software to check 3D deviations quantitatively and qualitatively. The accuracy data were statistically analyzed using one-way ANOVA for build orientation comparison and independent sample t-test for structure density comparison at (α = .05). Points study analysis targeting RPD components and representative color maps were also studied. RESULTS. The build orientation of 135-degree angle of the maxillary frameworks showed the lowest deviation at the clasp arms of tooth 26 of the 135-degree angle group. The mandibular frameworks with 150-degree angle build orientation showed the least deviation at the rest on tooth 44 and the arm of the I-bar clasp of tooth 45. No significant difference was seen between different support structure densities. CONCLUSION. Build orientation had an influence on the accuracy of the frameworks, especially at a 135-degree angle of maxillary design and 150-degree of mandibular design. The difference in the support's density structure revealed no considerable effect on the accuracy.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2016.05a
• /
• pp.302-304
• /
• 2016

The purpose of this paper is to draw comparison between the performance of ${\alpha}-{\beta}-{\gamma}$ filter and Kalman filter of a tracking module for ARPA system on board high dynamic warship. The comparison is based on the filters' capability to reduce residual error and maintain a stable transient response. The residual error is computed from the difference between the observed the predicted positions for the entire tracking period. The results indicate that the Kalman filter has a higher tracking accuracy compared to the optimal ${\alpha}-{\beta}-{\gamma}$ filter. However, both filters have a similar transient response.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.4 no.2
• /
• pp.27-41
• /
• 1986

In this study, practical use of TM (Thematic Mapper) data was evaluated by comparison of LANDSAT- 5 TM and MSS (Multispectral Scanner) data. The comparison of TM and MSS data was achieved by analyzing the result of landuse mapping of Incheon area, and in addition, the comparison of accuracy according to image enhancement method was made. From the results of this study, we found that TM data was more accurate by about 20% than MSS data in landuse mapping, and that smoothing was effective in image enhancement processing of TM data.