• Journal of Astronomy and Space Sciences
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• v.33 no.3
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• pp.177-183
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• 2016

Active galactic nuclei (AGN) are too compact to be resolved by any existing optical telescope facility, making it difficult to understand their structure and the emission processes responsible for their huge energy output. However, variability, one of their characteristic properties, provides a tool to probe the inner regions of AGN. Blazars are the best candidates for such a study, and hence a considerable amount of effort is being made to investigate variability in these sources across the electromagnetic spectrum. Here, using the Mt. Abu infrared observatory (MIRO) blazar monitoring program, we present intra-night, inter-night, and long term aspects of the variability in S5 0716+71, 3C66A, and OJ 287. These stars show significant variability on short (a few tens of mins, to a few hours, to a few days) to long term (months to years) timescales. Based on the light travel time argument, the shortest variability timescales (micro-variability) provide upper limits to the size of the emission region. While S5 0716 shows a very high duty cycle of variability (> 80 %), 3C66A shows a much lower intra day variability (IDV) duty cycle (< 20 %). All three show rapid variations within 2.5 to 3.5 hr, which, perhaps, are generated near the vicinity of black holes. Assuming this, estimates of the masses of the black holes are made at ~10⁹, 8×10⁸, and 2.7×10⁹ M_⨀ for S5 0716+71, 3C66A, and OJ 287, respectively. Multi-wavelength light-curves for the blazar PKS 1510-089 are discussed to infer the emission processes responsible for the recent flaring episodes in this source.

• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.175-182
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• 2002

Dental caries is a chronic disease that causes the destruction of tooth structure by the interaction of plaque bacteria, food debris, and saliva. There has been attempts to induce remineralization by supersaturating the Intra-oral environment around the surface enamel, where there is incipient caries. In this study, supersaturated remineralized solution "R" was applied to specimens with incipient enamel caries, and the quantitative analysis of remineralization was evaluated using microradiography. Thirty subjects volunteered to participate in this study. Removable appliances were constructed for the subjects, and the enamel specimen with incipient caries were embedded in the appliances. The subjects wore the intra-oral appliance for 15 days except while eating and sleeping. The removable appliance were soaked in supersaturated solution "R", saline, or Senstime$^{\circledR}$ to expose the specimen to those solutions three times a day, 5 minutes each time. After 15 days, microradiography was retaken to compare and evaluate remineralization The results were as the following: 1. The ratio of remineralized area to demineralized area was significantly higher in the supersaturated solution "R" and Senstime$^{\circledR}$ than in the saline (p<0.05) 2. Remineralization in the supersaturated buffer solution "R" occurred in the significantly deeper parts of the tooth. compared to the Senstime$^{\circledR}$ group containing high concentration or fluoride. (p<0.05) As in the above results, the remineralization effect of remineralized buffer solution "R" on incipient enamel caries has been proven. For clinical utilization, further studies on soft tissue reaction and the effect on dentin and cementum are necessary In conclusion compared to commercially available fluoride solution. remineralization solution“R”showed better remineralization effect on early enamel caries lesion, so it is considered as effecient solution for clinical application.

• Research in Community and Public Health Nursing
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• v.32 no.4
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• pp.415-429
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• 2021

Purpose: The purpose of this study was to develop the Self-Care Non-adherence Risk Assessment Scale (SCNRAS) for patients with chronic illness in South Korea. Methods: This study was conducted from April to July, 2020 and utilized a convenience sampling method to recruit 336 patients with chronic illness from three hospitals located in South Korea. The content, factorial structure, item-convergent/discriminant validity, convergent validity, internal consistency reliability, and test-retest reliability of the scale were evaluated. The data were analyzed using exploratory and confirmatory factor analyses, Pearson's correlation coefficient, Cronbach's α, and intra-class correlation coefficient. Results: The exploratory and confirmatory factor analyses yielded six-factors. Convergent validity was demonstrated using measures of defining issues. Internal consistency reliability and test-retest reliability were found to be acceptable, as indicated by a Cronbach's α of .65~.81 and an intra-class correlation coefficient of .93~.98. The Self-Care Non-adherence Risk Assessment Scale for patients with chronic illness is a new instrument that comprehensively measures the knowledge, skill, physical function status, access to health care, social support, motivation, and confidence. It comprises 18 items scored on a 5-point Likert scale. The validity and reliability of the scale were verified. Conclusion: The scale developed through this study is expected to screen those who need nursing intervention early by predicting the self-care non-adherence risk group.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.383-388
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• 2021

Purpose: The aim of this study was to evaluate the root canal morphology of mesial roots of mandibular first molars. Materials and Methods: Forty extracted mandibular first molars were used in this study. The morphological examination of root canals was conducted in accordance with the Vertucci classification using micro-computed tomography (micro-CT). Any aberrant root canal configurations not included in the Vertucci classification were recorded, and their frequency was established using descriptive statistics. Intra-observer reliability was assessed using the Wilcoxon signed-rank test, while inter-observer reliability was assessed using the Cohen kappa test. Significance was evaluated at the P<0.05 level. Results: The mesial roots of mandibular first molars had canal configurations of type I (15%), type II (7.5%), type III (25%), type IV (10%), type V (2.5%), type VI (7.5%), and type VII (7.5%). The images showed 10 (25%) additional configuration types that were not included in the Vertucci classification. These types were 1-3-2-3, 1-2-3-2-3, 2-3-1, 2-3, 1-2-3-1, 2-1-2-3, 3-2-1, 1-2-3-1, 2-3-2-3, and 1-2-1-2-1. The intra-observer differences were not statistically significant(P>0.05) and the kappa value for inter-observer agreement was found to be 0.957. Conclusion: Frequent variations were detected in mesial roots of mandibular first molars. Clinicians should take into consideration the complex structure of the root canal morphology before commencing root canal treatment procedures to prevent iatrogenic complications. Micro-CT was a highly suitable method to provide accurate 3-dimensional visualizations of root canal morphology.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.449-458
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• 2023

Many people think that sign language is only for people who are deaf and cannot speak, but of course it is necessary for people who want to talk with them. One of the biggest challenges in ASL(American Sign Language) alphabet recognition is the high inter-class similarities and high intra-class variance. In this paper, we proposed an architecture that can overcome these two problems, which performs similarity learning to reduces inter-class similarities and intra-class variance between images. The proposed architecture consists of the same convolutional neural network with a double configuration that shares parameters (weights and biases) and also applies the Keras API to reduce similarity learning and variance through this pathway. The similarity learning results the use of the dual CNN shows that the accuracy is improved by reducing the similarity and variability between classes by not including the poor results of the two classes.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.106-107
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• 2010

본 논문에서는 H.264/AVC의 부호화 효율을 향상 시킬 수 있는 방법을 제안하였다. 제안하는 알고리즘은 확장된 매크로 블록에서 향상된 인트라 예측 및 인터 예측 블록 혼합 코딩 방법을 사용한다. 그리고 인터 블록부터 먼저 부호화 및 복호화하여 인트라 예측 시 참조 픽셀로 사용하는 것을 제안한다. 기존의 인트라 예측 방법에서는 현재 블록의 우측 픽셀들과 하단에 위치한 픽셀들을 이용하지 못하기 때문에 예측 정확도가 높지 않았다. 따라서 본 논문에서는 현재 부호화하려는 블록의 상단과 좌측뿐만 아니라 우측 또는 하단의 복호화가 완료된 픽셀을 이용하여, 예측을 수행하는 확장된 인트라 예측 방법을 제안한다. 그리고 실험을 통하여 제안하는 방법이 기존 기술에 비해 효율적인 것을 보인다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.78-81
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• 2010

In this paper, we propose an efficient and effective selective protection scheme to SVC that exploit the propagation of protection effect by protecting significant frames that can give the maximum visual quality degradation. We model SVC dependency coding structure as a directed acyclic graph which is characterized with an estimated visual quality value as the attribute at each node. The estimated visual quality is calculated by using our model based on the proportions of intra- and inter-predicted MBs, amounts of residual, and estimated visual quality of reference frames. The proposed selective protection scheme traverses the graph to find optimal protection paths that can give maximum visual quality degradation. Experimental results show that the proposed selective protection scheme reduces the required number of frames to be protected by 46.02% compared to the whole protection scheme and 27.56% compared to the layered protection scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.1093-1104
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• 2014

The High Efficiency Video Coding (HEVC) is a new video coding standard that can provide much better compression efficiency than its predecessor H.264/AVC. However, it is computationally more intensive due to the use of flexible quadtree coding unit structure and more choices of prediction modes. In this paper, a fast intraframe coding scheme is proposed for HEVC. Firstly, a fast bottom-up pruning algorithm is designed to skip the mode decision process or reduce the candidate modes at larger block size coding unit. Then, a low complexity rough mode decision process is adopted to choose a small candidate set, followed by early DC and Planar mode decision and mode filtering to further reduce the number of candidate modes. The proposed method is evaluated by the HEVC reference software HM8.2. Averaging over 5 classes of HEVC test sequences, 41.39% encoding time saving is achieved with only 0.77% bitrate increase.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.111-111
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• 2012

In this talk, we represent a novel approach to investigating intra-nanorod surface plasmon coupling with control over block compositions. The multi-component rod-like nanostructures, which consist of optically active components (Au and Ag) and optically less active component (for example, Ni) in UV-vis-NIR spectral window, showed interesting optical response depending on each block length and the total length of the structure. By controlling the composition and relative lengths of the blocks that comprise these structures, we can tailor the overall optical properties. Depending on the relative fraction of Au and Ag blocks, the intensity of the transverse modes varied without noticeable peak shifts. However, the strong intraparticle surface plasmon coupling resulted in the collective appearance of longitudinal LSP modes, including higher-order modes. The experimental observations were confirmed by theoretical calculation, using a discrete dipole approximation method. In addition, we will briefly discuss how single nanorod solar cells can be synthesized by using by using electrochemical deposition and AAO hard templates.

• Journal of Korean Dental Science
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• v.6 no.1
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• pp.4-12
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• 2013

Purpose: This study sought to verify the usefulness of mini-implant and surgical steel wire in the treatment of mandibular fracture through the objective identifi cation of the change of bone structure and bone density before and after reduction by evaluating radiological change through fractal analysis when mandibular fracture is treated using mini-implant and surgical wire. Materials and Methods: This study looked at 45 patients (males: 38, female: 7) diagnosed with mandibular fracture in the oral and maxillofacial surgery division of Chung-Ang University Dental Hospital and who received open reduction and intra-osseous fi xation. Result: The average fracture dimension values were higher for the group of the patients who had mini-implants and surgical wire treatment. Conclusion: Based on the results of the study on the usefulness of the reduction technique using mini-implant and surgical steel wire in the treatment of mandibular fracture through the fractal analysis method, the reduction technique using mini-implant and surgical steel wire is regarded as an effective method of minimizing the gap between mandibular fracture fragments.