• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.259-264
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• 2006

It is well known that the uncertainty of the covariance parameters of the process noise (Q) and the observation errors (R) has a significant impact on Kalman filtering performance. Q and R influence the weight that the filter applies between the existing process information and the latest measurements. Errors in any of them may result in the filter being suboptimal or even cause it to diverge. The conventional way of determining Q and R requires good a priori knowledge of the process noises and measurement errors, which normally comes from intensive empirical analysis. Many adaptive methods have been developed to overcome the conventional Kalman filter's limitations. Starting from covariance matching principles, an innovative adaptive process noise scaling algorithm has been proposed in this paper. Without artificial or empirical parameters to be set, the proposed adaptive mechanism drives the filter autonomously to the optimal mode. The proposed algorithm has been tested using road test data, showing significant improvements to filtering performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.452-472
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• 2019

Most existing wavelet-based multiplicative watermarking methods are affected by geometric attacks to a certain extent. A serious limitation of wavelet-based multiplicative watermarking is its sensitivity to rotation, scaling, and translation. In this study, we propose an image watermarking method by using dual-tree complex wavelet transform with a multi-objective optimization approach. We embed the watermark information into an image region with a high entropy value via a multiplicative strategy. The major contribution of this work is that the trade-off between imperceptibility and robustness is simply solved by using the multi-objective optimization approach, which applies the watermark error probability and an image quality metric to establish a multi-objective optimization function. In this manner, the optimal embedding factor obtained by solving the multi-objective function effectively controls watermark strength. For watermark decoding, we adopt a maximum likelihood decision criterion. Finally, we evaluate the performance of the proposed method by conducting simulations on benchmark test images. Experiment results demonstrate the imperceptibility of the proposed method and its robustness against various attacks, including additive white Gaussian noise, JPEG compression, scaling, rotation, and combined attacks.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.6
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• pp.309-317
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• 2022

In this paper, we propose a machine learning-based copy-move forgery detection network with dual branches. Because the rotation or scaling operation is frequently involved in copy-move forger, the conventional convolutional neural network is not effectively applied in detecting copy-move tampering. Therefore, we divide the input into rotation-invariant and scaling-invariant features based on the wavelet coefficients. Each of the features is input to different branches having the same structure, and is fused in the combination module. Each branch comprises feature extraction, correlation, and mask decoder modules. In the proposed network, VGG16 is used for the feature extraction module. To check similarity of features generated by the feature extraction module, the conventional correlation module used. Finally, the mask decoder model is applied to develop a pixel-level localization map. We perform experiments on test dataset and compare the proposed method with state-of-the-art tampering localization methods. The results demonstrate that the proposed scheme outperforms the existing approaches.

• Korean journal of food and cookery science
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• v.24 no.6
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• pp.763-770
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• 2008

A taste-testing method that accurately measures consumer-acceptance is critical during the course of the product development stage. Although various types of consumer-acceptance tests are available, the testing protocol appropriate for measuring the acceptance of ready-to-eat-meals (REM) has not yet been verified. In this study, various hedonic taste-testing methods (9-point hedonic scaling, best-worst scaling, open ended response) were compared for their efficiency and power in identifying the preferred REM menu of consumers. Forty-four consumers evaluated the acceptance of five types of REM menu samples consisting of a wide variety of flavors. Consumers initially used the 9-point hedonic rating method to choose the best and the worst sample among the 5 meals tested. Finally, consumers were asked to fill out open-ended comments where they could freely describe their liking and disliking of each sample. The results showed that the REM menu acceptance measured by the 9-point hedonic method that rated best-worst scaling exhibited a similar preference pattern. The open-ended response method could not provide a quantifiable acceptance data but was able to provide supplementary information regarding the limitations of the samples and therefore, provide a general idea of the direction of improvement during the product development.

• The Journal of Advanced Prosthodontics
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• v.10 no.3
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• pp.197-204
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• 2018

PURPOSE. To determine the extent of treatment traces, the roughness depth, and the quantity of titanium nitride (TiN) removed from the surface of CAD/CAM abutments after treatment with various instruments. MATERIALS AND METHODS. Twelve TiN coated CAD/CAM abutments were investigated for an in vitro study. In the test group (9), each abutment surface was subjected twice (150 g vs. 200 g pressure) to standardized treatment in a simulated prophylaxis measure with the following instruments: acrylic scaler, titanium curette, and ultrasonic scaler with steel tip. Three abutments were used as control group. Average surface roughness (Sa) and developed interfacial area ratio (Sdr) of treated and untreated surfaces were measured with a profilometer. The extent of treatment traces were analyzed by scanning electron microscopy. RESULTS. Manipulation with ultrasonic scalers resulted in a significant increase of average surface roughness (Sa, P<.05) and developed interfacial area ratio (Sdr, P<.018). Variable contact pressure did not yield any statistically significant difference on Sa-values for all instruments (P=.8). Ultrasonic treatment resulted in pronounced surface traces and partially detachment of the TiN coating. While titanium curettes caused predominantly moderate treatment traces, no traces or detectable substance removal has been determined after manipulation with acrylic curettes. CONCLUSION. Inappropriate instruments during regular plaque control may have an adverse effect on the integrity of the TiN coating of CAD/CAM abutments. To prevent defects and an increased surface roughness at the transmucosal zone of TiN abutments, only acrylic scaling instruments can be recommended for regular maintenance care.

• Journal of Periodontal and Implant Science
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• v.43 no.6
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• pp.283-290
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• 2013

Purpose: The concept of gingival biotype has been used as a predictor of periodontal therapy outcomes since the 1980s. In the present study, prospective and controlled experiments were performed to compare periodontal pocket depth (PPD) reduction and gingival shrinkage (GSH) after scaling and root planing (SRP) according to gingival biotype. Methods: Twenty-five patients diagnosed with chronic periodontitis participated in the present study. The PPD and GSH of the labial side of the maxillary anterior teeth (from the right canine to the left canine) were evaluated at baseline and 3 months after SRP. Changes in the PPD following SRP were classified into 4 groups according to the gingival thickness and initial PPD. Two more groups representing normal gingival crevices were added in evaluation of the GSH. The results were statistically analyzed using the independent t-test. Results: In the end, 16 patients participated in the present study. With regard to PPD reduction, there were no significant differences according to gingival biotype (P>0.05). Likewise, sites with a PPD of over 3 mm failed to show any significant differences in the GSH (P>0.05). However, among the sites with a PPD of under 3 mm, those with the thin gingival biotype showed more GSH (P<0.05). Conclusions: PPD changes after SRP were not affected by gingival biotype with either shallow or deep periodontal pockets. GSH also showed equal outcomes in all the groups without normal gingival crevices. The results of SRP seem not to differ according to gingival biotype.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.561-564
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• 2008

Concrete scaling is the progressive surface deterioration of susceptible subjected to freeze-thaw cycling in the presence of moisture. Particularly, it has been recognized that chlorides present in deicing agents can significantly increase concrete surface scaling. Domestic area of most be happened chloride deicer damage. Because daily mean temperature is below 0$^{\circ}C$ from the area of domestic most. Use of deicing chemicals has been and will continue to be a major part of highway snow and ice control methods. Chloride-containing chemicals such as calcium chloride or rock salt are main deicers for the road. Extensive use of chloride deicers is, however, not only the source of substantial cost penalties due to their corrosive action and ability to deterioration roadway surface materials but also the source of environmental damages. In this study, Use of (40, 27, 21MPa) pavement concrete analyze freeze-thaw test and scaling on the chlorides present.

• Journal of dental hygiene science
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• v.19 no.3
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• pp.190-197
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• 2019

Background: The Internet has advantages in terms of accessibility and amount of information, and the search for health information over the Internet is increasing exponentially. The purpose of this study is to analyze the information generated about some dental treatment on the internet by year. Methods: Naver Knowledge (JisikIn in Korean) which is an interactive search service was selected as the first search site in Korea. Scaling, wisdom tooth extraction, and endodontic treatment that can be paid by Korean health insurance were selected. Finally, 4,729 questions about scaling, 23,963 wisdom teeth extraction questions and 17,733 endodontic treatment questions were extracted. The question contents, the information about the questioner and the answerer, and an error of answers were investigated. Frequency analysis was used and chi-square test was used if necessary. Results: The most frequently asked questions were discomfort and dissatisfaction after the treatment. The need for treatment was the second in questions of the wisdom tooth extraction and endodontic treatment, but the health insurance benefit was the second in dental scaling. Most of the questioners didn't disclose personal information. The public answered the most in 2013~2014, but the highest percentage of the respondents was experts in 2017. Responses were mostly personal experience, but showed a tendency to decrease with years, and professional knowledge showed an increasing tendency. The error of the answer has also gradually decreased. Conclusion: Questions about dental care over the Internet are increasing exponentially, experts are responding increasingly, and errors in answers are decreasing. Nevertheless, it is necessary to pay attention to the related expert group to prevent misinformation.

• Journal of Environmental Science International
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• v.29 no.1
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• pp.25-32
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• 2020

The determination of soil parameters is important in predicting the simulated surface runoff using either a distributed or a lumped rainfall-runoff model. Soil characteristics can be collected using remote sensing techniques and represented as a digital map. There is no universal agreement with respect to the determination of a representative parameter from a gridded digital map. Two representative methods, i.e., arithmetic and predominant, are introduced and applied to both FLO-2D and HEC-HMS to improve the model's accuracy. Both methods are implemented in the Yongdam catchment, and the results show that the former seems to be more accurate than the latter in the test site. This is attributed to the high conductivity of the dominant soil class, which is A type.

• Journal of Korean society of Dental Hygiene
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• v.12 no.4
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• pp.647-654
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• 2012

Objectives : To propose the data for prevention of oral health problems through assessment on the knowledge, cognition and practice about oral health care of the clients who visit dental clinics. Methods : The subjects were total 400 clients from the four dental clinics in Busan city. Their knowledge, cognition and performances about oral healthcare collected with questionnaire survey from February to March, 2011. The rate and mean compared by chi-square test, t-test, and ANOVA. Results : Mean level of their knowledge, recognition and practice were 72.5, 80.2, and 65.6, respectively. Theses levels were higher in women (p<0.01), in the group of higher interested (p<0.001), immediately treated (p<0.001), correct tooth brushing (p<0.05), toothbrushing educated (p<0.001), take regular scaling (p<0.001), use assistant hygiene items (p<0.001), instead no differences by age and education level. And, the rate of correct toothbrushing was higher as 1.24 (1.03~1.50) times in the group with higher knowledge level, the rate of immediate treatment and regular scaling were higher as 1.35 (1.07~1.70) times, and 2.26 (1.41~3.64) times in the group with higher recognition level, respectively. Conclusions : These results demonstrate that insufficient knowledge and recognition of oral health care are related to a lack of its practice. Though their primary goal of the visits was treatment, the clients' attention needed to raise the comprehensive knowledge and recognition levels for their oral health promotion, especially reach to the performance level rather than simple knowledge acquisition. And more, to achieve the efficient oral health promotion, the importance of early treatment and strengthened efforts for prevention should be emphasized.