• Journal of Periodontal and Implant Science
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• 제50권6호
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• pp.358-367
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• 2020

Purpose: The aim of this study was to investigate the efficacy and validity of subgingival bacterial sampling using a retraction cord, and to evaluate how well this sampling method reflected changes in periodontal conditions after periodontal therapy. Methods: Based on clinical examinations, 87 subjects were divided into a healthy group (n=40) and a periodontitis group (n=47). Clinical measurements were obtained from all subjects including periodontal probing depth (PD), bleeding on probing (BOP), clinical attachment loss (CAL), and the plaque index. Saliva and gingival crevicular fluid (GCF) as a subgingival bacterial sample were sampled before and 3 months after periodontal therapy. The salivary and subgingival bacterial samples were analyzed by reverse-transcription polymerase chain reaction to quantify the following 11 periodontal pathogens: Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythus (Tf), Treponema denticola (Td), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn), Pavimonas micra (Pm), Campylobacter rectus (Cr), Prevotella nigrescens (Pn), Eikenella corrodens (Ec), and Eubacterium nodatum (En). Results: Non-surgical periodontal therapy resulted in significant decreases in PD (P<0.01), CAL (P<0.01), and BOP (P<0.05) after 3 months. Four species (Pg, Tf, Pi, and Pm) were significantly more abundant in both types of samples in the periodontitis group than in the healthy group. After periodontal therapy, Cr was the only bacterium that showed a statistically significant decrease in saliva, whereas statistically significant decreases in Cr, Pg, and Pn were found in GCF. Conclusions: Salivary and subgingival bacterial sampling with a gingival retraction cord were found to be equivalent in terms of their accuracy for differentiating periodontitis, but GCF reflected changes in bacterial abundance after periodontal therapy more sensitively than saliva.

• 한국차세대컴퓨팅학회논문지
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• 제15권5호
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• pp.53-63
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• 2019

모바일 환경에서 딥러닝을 통한 손 제스처 인터페이스를 제공하려면 높은 인식률을 제공하면서 실행속도의 저하를 막기 위한 네트워크 경량화의 연구가 필수적이다. 본 논문은 딥러닝 모델의 경량화를 통해 모바일 기기에서 손가락을 이용하여 공중에 쓴 문자를 실시간으로 인식하는 방법을 제안한다. MobileNet을 특징 추출기로 활용하는 객체 탐지 모델인 SSD (Single Shot Detector)를 기반으로 집게손가락을 탐지하고 손끝 경로를 이어 결과문자 영상을 생성한다. 이 영상은 서버로 전송되어 정규화 과정을 수행한 다음 학습된 OCR 모델을 이용하여 문자를 인식한다. 본 방법을 검증하기 위하여 12명의 사용자가 GALAXY S10+ 기기를 사용하여 1,000개의 단어를 실험한 결과 평균 88.6%의 정확도로 손가락을 인식하고 124 ms 이내로 인식된 텍스트가 출력되어 실시간으로 활용 가능함을 알 수 있었다. 본 연구결과는 모바일 환경에서 손가락을 이용한 간단한 문자 전송, 메모 및 공중 서명 등에 활용될 수 있다.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4122-4129
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• 2021

The counting efficiencies obtained using anthropomorphic physical phantoms are generally used in whole-body counting measurements to determine the level of internal contamination in the body. Geometrical discrepancies between phantoms and measured individuals affect the counting efficiency, and thus, considering individual physical characteristics is crucial to improve the accuracy of activity estimates. In the present study, the counting efficiencies of whole-body counting measurements were calculated considering individual physical characteristics by employing Monte Carlo simulation for calibration. The NaI(Tl)-based stand-up and HPGe-based bed type commercial whole-body counters were used for calculating the counting efficiencies. The counting efficiencies were obtained from 19 computational phantoms representing various shapes and sizes of the measured individuals. The discrepancies in the counting efficiencies obtained using the computational and physical phantoms range from 2% to 33%, and the results indicate that the counting efficiency depends on the size of the measured individual. Taking into account the body size, the equations for estimating the counting efficiencies were derived from the relationship between the counting efficiencies and the body-build index of the subject. These equations can aid in minimizing the size dependency of the counting efficiency and provide more accurate measurements of internal contamination in whole-body counting measurements.

• Journal of Oral Medicine and Pain
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• 제44권2호
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• pp.54-58
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• 2019

Purpose: The aim of this study is to evaluate the correlation between tongue pain and tenderness of tongue by digital palpation (DP) in Burning Mouth Syndrome (BMS) patients. Methods: One hundred thirty-four consecutive patients (60 BMS with tongue pain and 74 non-BMS) who attended the Department of Oral Medicine (Chosun University Dental Hospital, Gwangju, Korea) from January 2018 to December 2018 were included in this study. The examined sites were anterior, lateral (right and left) and central part of the tongue. The pain sites were reported by the patients and the tender points on DP test were recorded by the clinicians. DP test was performed by well-trained clinicians with palpation of the tongue with 0.5 kg pressure using the thumb and index finger. Obtained results for BMS and non-BMS group were compared using t-test (p<0.05). Results: 1. The BMS group had higher tender score on DP test of the tongue and there was a significant difference between the BMS and non-BMS groups. 2. The accuracy of the pain site and the tender point was shown to be 0.68 total (anterior 0.68; right lateral 0.69; left lateral 0.70; central 0.61). Conclusions: This study suggests that the tenderness to DP of the tongue could be related to the painsites in the BMS patients. Further study is needed to confirm the usefulness of DP test of the tongue to examine the BMS patients.

• 한국농공학회논문집
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• 제61권4호
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• pp.1-10
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• 2019

Unmanned aerial vehicle(UAV) can acquire images with lower cost than conventional manned aircraft and commercial satellites. It has the advantage of acquiring high-resolution aerial images covering in the field area more than 50 ha. The purposes of this study is to develop the rice grain yield distribution using UAV. In order to develop a technology for estimating the rice yield using UAV images, time series UAV aerial images were taken at the paddy fields and the data were compared with the rice yield of the harvesting area for two rice varieties(Singdongjin, Dongjinchal). Correlations between the vegetation indices and rice yield were ranged from 0.8 to 0.95 in booting period. Accordingly, rice yield was estimated using UAV-derived vegetation indices($R^2=0.70$ in Sindongjin, $R^2=0.92$ in Donjinchal). It means that the rice yield estimation using UAV imagery can provide less cost and higher accuracy than other methods using combine with yield monitoring system and satellite imagery. In the future, it will be necessary to study a variety of information convergence and integration systems such as image, weather, and soil for efficient use of these information, along with research on preparing management practice work standards such as pest control and nutrient use based on UAV image information.

• Structural Engineering and Mechanics
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• 제71권2호
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• pp.185-196
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• 2019

In this investigation, study of the static and dynamic behaviors of functionally graded beams (FGB) is presented using a hyperbolic shear deformation theory (HySDT). The simply supported FG-beam is resting on the elastic foundation (Winkler-Pasternak types). The properties of the FG-beam vary according to exponential (E-FGB) and power-law (P-FGB) distributions. The governing equations are determined via Hamilton's principle and solved by using Navier's method. To show the accuracy of this model (HySDT), the current results are compared with those available in the literature. Also, various numerical results are discussed to show the influence of the variation of the volume fraction of the materials, the power index, the slenderness ratio and the effect of Winkler spring constant on the fundamental frequency, center deflection, normal and shear stress of FG-beam.

• 한국정보전자통신기술학회논문지
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• 제12권3호
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• pp.251-256
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• 2019

본 연구에서는 손동작을 인식하기 위하여 밀리미터파 기반 레이더에서 얻어진 손동작의 주파수 반향 특성을 이용하는 알고리즘 및 시스템을 제안하였다. 제안된 시스템은 밀리미터파 아날로그 송수신부, ADC부 및 신호 처리부가 원칩으로 구현된 시스템을 이용하여 데이터를 수집하도록 구성하였고, 제안한 알고리즘은 반사된 주파수 영상의 제르니케모멘트로부터 얻어진 전역 및 지역 디스크립터로 구성된 BoF에서 K-means 클러스터링을 이용하여 코드 워드를 생성하고 SVM을 이용한 손동작 분류를 수행하였다. 수행 결과는 혼동행렬에서 얻어진 정밀도, 민감도 및 정확도를 이용하여 평가였다. 정확도 평가에서는 제안한 방법은 GZM방법 및 LZM방법과 비교하여 성능 평가를 위한 인덱스에서 제안한 방법이 95.6%의 성능을 보였고 비교한 나머지 두 방법은 88.4% 및 84%을 나타내어 제안한 방법이 기존의 두 방법에 비하여 7~8% 성능이 향상되었으며 정밀도 및 민감도에서도 나머지 두 방법에 대하여 향상된 성능을 나타내었다. 제안한 방법은 소형화된 밀리미터파 기반 레이더를 이용하여 동작 인식을 할 수 있는 임베디드 시스템의 응용가능성을 보여준다.

• 공업화학
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• 제30권1호
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• pp.29-33
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• 2019

탄소 nanotube, nanofiber 및 powder를 사용하여 아세틸렌 흡착실험을 수행한 결과 탄소 nanotube가 최적의 흡착성분을 보였다. 이를 지지체로 하여 Pd 농도 0~5%, 흡착온도 $30{\sim}80^{\circ}C$ 및 $C_2H_2/CO_2$의 비 3~10의 범위에서 3-요인, 3-수준의 Box-Behnken Design(BBD)으로 15개의 실험 조건을 설계했다. 이를 바탕으로 2차 다항식 회귀분석으로 운전조건에 따른 흡착량 예측식을 도출하였다. ANOVA 분석의 F-value 측정에 따라 흡착온도가 가장 큰 영향지수를 보였고 $C_2H_2/CO_2$의 비는 가장 작은 영향지수 보이는 것으로 나타났다. 하지만 주요인자 간의 교호작용은 거의 없는 것으로 분석되었다. 흡착량 최적화 분석에서 Pd 농도 3.0%, 흡착온도 $47^{\circ}C$ 및 $C_2H_2/CO_2=10$인 조건에서 22.0 mmol/g이 흡착되는 것으로 계산되었고 실제 실험치에 95.9%의 정확도를 보였다.

• 디지털산업정보학회논문지
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• 제14권4호
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• pp.35-45
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• 2018

Users are sharing many of contents such as text, image, video, and so on in SNS. There are various information as like as personal interesting, opinion, and relationship in social media contents. Therefore, many of recommendation systems or search systems are being developed through analysis of social media contents. In order to extract subject-related topics of social context being collected from social media channels in developing those system, it is necessary to develop ontologies for semantic analysis. However, it is difficult to develop formal ontology because social media contents have the characteristics of non-formal data. Therefore, we develop a social topic system based on semantic and subject correlation. First of all, an extracting system of social topic based on semantic relationship analyzes semantic correlation and then extracts topics expressing semantic information of corresponding social context. Because the possibility of developing formal ontology expressing fully semantic information of various areas is limited, we develop a self-extensible architecture of ontology for semantic correlation. And then, a classifier of social contents and feed back classifies equivalent subject's social contents and feedbacks for extracting social topics according semantic correlation. The result of analyzing social contents and feedbacks extracts subject keyword, and index by measuring the degree of association based on social topic's semantic correlation. Deep Learning is applied into the process of indexing for improving accuracy and performance of mapping analysis of subject's extracting and semantic correlation. We expect that proposed system provides customized contents for users as well as optimized searching results because of analyzing semantic and subject correlation.

• Coupled systems mechanics
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• 제8권4호
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• pp.315-338
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• 2019

The numerical investigations have been carried out on reinforced concrete slab against blast loading to demonstrate the accuracy and effectiveness of the finite element based numerical models using commercial package ABAQUS. The response of reinforced concrete slab have been studied against the influence of weight of TNT, standoff distance, boundary conditions, influence of air blast and surface blast. The results thus obtained from simulations were compared with the experiments available in literature. The inelastic behavior of concrete and steel reinforcement bar has been incorporated through concrete damage plasticity model and Johnson-cook models available in ABAQUS were presented. The predicted results through numerical simulations of the present study were found in close agreement with the experimental results. The damage mechanism and stress response of target were assessed based on the intensity of deformations, impulse velocity, von-Mises stresses and damage index in concrete. The results indicate that the standoff distance has great influence on the survivability of RC slab against blast loading. It is concluded that the velocity of impulse wave was found to be decreased from 17 to 11 m/s when the mass of TNT is reduced from 12 to 6 kg. It is observed that the maximum stress in the concrete was found to be in the range of 15 to $20N/mm^2$ and is almost constant for given charge weight. The slab with two short edge discontinuous end condition was found better and it may be utilised in designing important structures. Also it is observed that the deflection in slab by air blast was found decreased by 60% as compared to surface blast.