• The Journal of Advanced Prosthodontics
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• 제14권6호
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• pp.360-368
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• 2022

PURPOSE. This study assessed the physical and mechanical properties of interim crown materials fabricated using various digital techniques after accelerated aging. MATERIALS AND METHODS. Three groups of interim dental restorative materials (N = 20) were tested. The first group (CO) was fabricated using a conventional manual method. The second group (ML) was prepared from prefabricated resin blocks for the milling method and cut into specimen sizes using a cutting disc. The third group (3D) was additively manufactured using a digital light-processing (DLP) 3D printer. Aging acceleration treatments using toothbrushing and thermocycling simulators were applied to half of the specimens corresponding to three years of usage in the oral environment (N = 10). Surface roughness (Ra), Vickers microhardness, 3-point bending, sorption, and solubility tests were performed. A 2-way analysis of variance (ANOVA) and Fisher's multiple comparison test were used to compare the results among the groups. RESULTS. The mean surface roughness (Ra) of the resin after accelerated aging was significantly higher in the CO and ML groups than that before aging, but not in the 3D group. All groups showed reduced hardness after accelerated aging. The flexural strength values were highest in the 3D group, followed by the ML and CO groups after accelerated aging. Accelerated aging significantly reduced water sorption in the ML group. CONCLUSION. According to the tested material and 3D printer type, both 3D-printed and milled interim restoration resins showed higher flexural strength and modulus, and lower surface roughness than those prepared by the conventional method after accelerated aging.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권2호
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• pp.391-411
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• 2023

Aggregates play the skeleton and supporting role in the construction field, high-precision measurement and high-efficiency analysis of aggregates are frequently employed to evaluate the project quality. Aiming at the unbalanced operation time and segmentation accuracy for multi-class segmentation algorithms of aggregate images, a Chaotic Sparrow Search Algorithm (CSSA) is put forward to optimize it. In this algorithm, the chaotic map is combined with the sinusoidal dynamic weight and the elite mutation strategies; and it is firstly proposed to promote the SSA's optimization accuracy and stability without reducing the SSA's speed. The CSSA is utilized to optimize the popular multi-class segmentation algorithm-Multiple Entropy Thresholding (MET). By taking three METs as objective functions, i.e., Kapur Entropy, Minimum-cross Entropy and Renyi Entropy, the CSSA is implemented to quickly and automatically calculate the extreme value of the function and get the corresponding correct thresholds. The image adaptive multi-class segmentation model is called CSSA-MET. In order to comprehensively evaluate it, a new parameter I based on the segmentation accuracy and processing speed is constructed. The results reveal that the CSSA outperforms the other seven methods of optimization performance, as well as the quality evaluation of aggregate images segmented by the CSSA-MET, and the speed and accuracy are balanced. In particular, the highest I value can be obtained when the CSSA is applied to optimize the Renyi Entropy, which indicates that this combination is more suitable for segmenting the aggregate images.

• 여성건강간호학회지
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• 제28권4호
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• pp.329-337
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• 2022

Purpose: The purpose of this study was to investigate the influence of eHealth literacy, reproductive health knowledge, and self-esteem on early adult women's health-promoting behaviors (HPB). This study was based on Pender's health promotion model as a theoretical underpinning. Methods: Early adult women aged 18 to 35 years (n=165) were recruited by posting advertisements on social network sites for a student club and a faith-based community in Ansan, Korea. Willing individuals were invited to participate in the online survey from June 1 to June 30, 2022. Standardized instruments were used to measure HPB, eHealth literacy, reproductive health knowledge, and self-esteem. General characteristics included income level, perceived subjective health, and internet usage time. The collected data were analyzed using the independent t-test, one-way analysis of variance, Pearson correlation coefficients, and multiple regression. Results: The mean age of the respondents was 21.97±3.87 years. The total HPB score was 120.69, corresponding to a moderate level; and the total scores for eHealth literacy (30.24), knowledge of reproductive health (23.04), and self-esteem (35.62) were higher than the midpoint. The model explained 53.3% of variance in HPB, and self-esteem (β=.48, p<.001) was the most influential factor. Other influential factors were, in descending order, higher economic level, higher subjective health status, greater eHealth literacy, and less internet use time (<2 hours/day). Conclusion: In order to promote the health of early adult women, counseling or programs that positively improve self-esteem appear promising, and eHealth literacy should be considered as a way to promote HPB using information technology.

• The Journal of Advanced Prosthodontics
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• 제16권1호
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• pp.57-65
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• 2024

PURPOSE. The aim of this stuldy was to compare the clinical marginal fit of CAD-CAM inlays obtained from intraoral digital impression or addition silicone impression techniques. MATERIALS AND METHODS. The study included 31 inlays for prosthodontics purposes of 31 patients: 15 based on intraoral digital impressions (DI group); and 16 based on a conventional impression technique (CI group). Inlays included occlusal and a non-occlusal surface. Inlays were milled in ceramic. The inlay-teeth interface was replicated by placing each inlay in its corresponding uncemented clinical preparation and taking interface impressions with silicone material from occlusal and free surfaces. Interface analysis was made using white light confocal microscopy (WLCM) (scanning area: 694 × 510 ㎛²) from the impression samples. The gap size and the inlay overextension were measured from the microscopy topographies. For analytical purposes (i.e., 95-%-confidence intervals calculations and P-value calculations), the procedure REGRESS in SUDAAN was used to account for clustering (i.e., multiple measurements). For p-value calculation, the log transformation of the dependent variables was used to normalize the distributions. RESULTS. Marginal fit values for occlusal and free surfaces were affected by the type of impression. There were no differences between surfaces (occlusal vs. free). Gap obtained for DI group was 164 ± 84 ㎛ and that for CI group was 209 ± 104 ㎛, and there were statistical differences between them (p = .041). Mean overextension values were 60 ± 59 ㎛ for DI group and 67 ± 73 ㎛ for CI group, and there were no differences between then (p = .553). CONCLUSION. Digital impression achieved inlays with higher clinical marginal fit and performed better than the conventional silicone materials.

• 한국균학회지
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• 제52권2호
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• pp.73-96
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• 2024

Root and stem rot caused by Phytophthora palmivora is one of the most serious diseases affecting durian production in Thailand where metalaxyl, an effective fungicide against oomycetes, has been used extensively for a long period to control this disease. Although field isolates of P. palmivora resistant to metalaxyl exist in Thailand, a molecular basis for P. palmivora has not yet been elucidated regarding metalaxyl resistance. The current study tested whether P. palmivora RPA1 (the DNA-directed RNA polymerase I subunit gene), a homolog gene of RPA190 associated with metalaxyl resistance in some isolates of Phytophthora infestans, had a role in the resistance mechanism toward metalaxyl. In total, 40 durian-derived isolates of P. palmivora were assessed for metalaxyl sensitivity using a mycelial growth inhibition assay. The effective concentrations for 50% mycelial growth inhibition values for all isolates tested were in the range 0.01-872.88 mg/L. The isolates were clustered into three groups: sensitive (n=23), moderately resistant (n=11), and resistant (n=6) groups. No polymorphism was revealed based on multiple alignment analysis of the amino acid sequences translated from the corresponding DNA sequences in the region of RPA1 of the metalaxyl-sensitive (n=5), moderately resistant (n=2), and resistant isolates (n=6). Furthermore, investigation of the RPA1 expression among these representative isolates (n=3, each group) indicated that RPA1 expression may not be involved in the regulation of P. palmivora resistance to metalaxyl. Based on this line of evidence, there was no detected relationship regarding metalaxyl resistance and P. palmivora RPA1.

• 대한환경공학회지
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• 제36권6호
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• pp.421-428
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• 2014

상수관망의 수리학적 거동을 해석함에 있어 현재까지 제안된 일반적인 방법은 유량기반 수리해석(Demand Driven Analysis, DDA)과 압력기반 수리해석(Pressure Driven Analysis, PDA)이다. DDA는 상수관망이 정상적으로 운영되는 상태에서 수리해석 결과를 빠르게 제시할 수 있으며, PDA는 관파괴 및 관내 저압력 상태시 DDA 방법으로는 모의할 수 없는 각 절점의 실질적인 공급가능유량을 제시할 수 있다. PDA 수행에 있어 우선적으로 각 절점에서 특정 압력마다 공급가능유량을 산정할 수 있는 관계식(Head-Outflow Relationship, HOR)을 결정해야 한다. 기존 연구들에서는 상수관망을 구성하는 각 절점에서 HOR이 다르고 각 절점의 HOR 검증을 위해서는 현장데이터의 실측이 필요하다고 지적하였다. 또한 다중 관파괴 상황과 같이 수리학적 조건이 변경된 상태에서 각 절점의 HOR 특성을 파악하기 위해서는 모든 절점에 모니터링 시스템이 구축되어 있어야 하는 제약조건이 있다. 본 연구는 실제 상수관망 형태의 모의 상수관망을 제작하여 상수관망의 정상상태 및 현장에서 측정이 어려운 비정상상태 운영조건을 시나리오별로 구성하고 각 조건 하에서 절점들의 압력 및 유량을 실시간으로 확인하였다. 또한 측정된 실험결과와 기존 HOR 관계식을 비교 평가하여 최소 오차 결과를 보이는 HOR을 제시하였으며, 특정 절점에서 다중 관파괴 발생시 HOR 특성을 파악하였다. 이로부터 관파괴 위치가 다르거나 다중 관파괴가 발생하더라도 특정 절점의 압력(수두) 저하에 따른 공급가능유량의 축소 현상은 본래 대상 절점이 가지고 있는 지수함수 형태인 고유한 HOR을 따라 감소하는 것으로 확인되었다. 본 연구에서 실험을 통해 측정한 압력-유량 관계와 기존 HOR 식들을 비교한 결과 최소 오차를 보이는 지수함수 형태의 Wagner 등1)이 제안한 식을 최적의 HOR 관계식으로 제안하며, 해당 식의 지수 m은 3.0으로 적용할 것을 제안한다.

• 지질공학
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• 제13권2호
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• pp.207-225
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• 2003

우리나라의 광역단열도가 작성되었다. 단열들에 대해 장미그림을 그려보면 북북동, 북서, 서북서의 세조의 우세 배향을 보여준다. 단열의 밀도는 태백산 광화대 지역이 가장 높게 나타나고, 태백산지역에서 서울까지 지역, 문경-보은탄전지역과 진안지역, 충남탄전지역, 고령-함안지역, 양산단층 및 가음단층지역 등이 밀도가 높은 편이다. 사천-지리산-전주선의 서남부 지역이 밀도가 가장 낮다. 지질별로는 조선누층군, 평안누층군, 대동누층군, 경상누층군 등 비변성 퇴적암 지역이 선캠브리아 기반암과 쥬라기 화강암 분포지역에 비해 단열 발달 밀도가 높다. 또 쥬라기 화강암에 비해 선켐브리아 기반암에서 단열발달 빈도가 상대적으로 높다. 우리나라의 광역단열을 길이를 토대로 $F_1,{\;}F_2,{\;}F_3,{\;}F_4$의 4등급으로 분류하였다. 등급별 단열의 배향은 자기유사(self-similar)하다고 하겠고 단열의 길이에 대한 누적 수 사이엔 누승법칙(power law) 분포를 지시한다. 지구조 구역별로 볼 때 단열은 경기육괴 지역과 경상분지 지역에서는 $F_1$에서부터 $F_4$까지 모든 등급 단열이 발달하나 그 외 지역은 F$_1$ 단열이 거의 발달되지 않는다. 양산단층을 포함한 대규모 단열들은 대부분 일회의 단층운동에 의해 지금의 연장을 가졌다기보다는 다중변형작용을 통한 변위의 집적으로 지금과 같은 길이를 이루었다고 보아야할 것이다. $F_1$ 단열을 제외한 다른 등급의 단열은 우리나라 전지역을 통해 고르게 발달한다고 볼 수 있다. 또 단열의 밀도는 옥천비변성대에서 가장 높게 나타나고 충남분지와 경상분지도 비교적 높다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권22호
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• pp.9731-9737
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• 2014

Large scale secular registry or surveillance systems have been accumulating vast data that allow mathematical modeling of cancer incidence and mortality rates. Most contemporary models in this regard use time series and APC (age-period-cohort) methods and focus primarily on predicting or analyzing cancer epidemiology with little attention being paid to implications for designing cancer registry, surveillance or evaluation initiatives. This research models age-specific cancer incidence rates using logistic growth equations and explores their performance under different scenarios of data completeness in the hope of deriving clues for reshaping relevant data collection. The study used China Cancer Registry Report 2012 as the data source. It employed 3-parameter logistic growth equations and modeled the age-specific incidence rates of all and the top 10 cancers presented in the registry report. The study performed 3 types of modeling, namely full age-span by fitting, multiple 5-year-segment fitting and single-segment fitting. Measurement of model performance adopted adjusted goodness of fit that combines sum of squred residuals and relative errors. Both model simulation and performance evalation utilized self-developed algorithms programed using C# languade and MS Visual Studio 2008. For models built upon full age-span data, predicted age-specific cancer incidence rates fitted very well with observed values for most (except cervical and breast) cancers with estimated goodness of fit (Rs) being over 0.96. When a given cancer is concerned, the R valuae of the logistic growth model derived using observed data from urban residents was greater than or at least equal to that of the same model built on data from rural people. For models based on multiple-5-year-segment data, the Rs remained fairly high (over 0.89) until 3-fourths of the data segments were excluded. For models using a fixed length single-segment of observed data, the older the age covered by the corresponding data segment, the higher the resulting Rs. Logistic growth models describe age-specific incidence rates perfectly for most cancers and may be used to inform data collection for purposes of monitoring and analyzing cancer epidemic. Helped by appropriate logistic growth equations, the work vomume of contemporary data collection, e.g., cancer registry and surveilance systems, may be reduced substantially.

• 한국음향학회지
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• 제22권1호
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• pp.1-6
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• 2003

본 논문에서는 시스토릭 어레이 구조를 갖는 선택적 최소분산 비왜곡응답 (MVDR) 및 최소자승 회귀기법 (RLS) 빔형성기법에 대한 성능 분석을 하였다. 원하는 사용자 신호와 잡음을 포함한 스냅샷 벡터들이 어레이 안테나에 입사되는 경우, 수신신호의 품질을 향상시키기 위해서 MVDR 및 RLS 알고리즘을 이용한 빔형성기법이 적용될 수 있다. 이를 통해 채널 용량을 증가시키기 위해 각 안테나 소자의 출력에 복소 가중치를 곱하여 원하는 사용자 신호방향으로 안테나의 빔을 형성하도록 하여 원하는 신호의 다중경로 성분들은 강조하고, 간섭 성분들의 입사 방향들로는 널을 발생시켜 다중간섭과 잡음에 대한 전력을 상대적으로 감소시키는 공간필터링 효과를 얻을 수 있다. 본 논문에서는 이러한 공간 필터 역할을 하는 MVDR기법과 RLS 기법을 병렬처리를 통해 수행할 수 있는 시스토릭 어레이 구조의 MVDR 및 RLS 빔형성기법에 대하여 소개하며, 이를 다중 경로와 다중 접속 간섭이 존재하는 채널 환경에 적용하여 수신 성능을 분석하였다. 컴퓨터 모의 실험을 통하여 제안된 시스토릭 어레이 구조의 빔 형성기법을 적용한 공간필터의 우수성을 보여주기 위해 사용자 증가에 따른 BER (Bit Error Rate) 곡선과 빔패턴을 제시하였고, 기대치와 실험치가 잘 부합됨을 확인하였다.

• Toxicological Research
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• 제30권1호
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• pp.7-11
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• 2014

Malondialdehyde (MDA), used as an oxidative stress marker, is commonly assayed by measuring the thiobarbituric acid reactive substances (TBARS) using HPLC, as an indicator of the MDA concentration. Since the HPLC method, though highly specific, is time-consuming and expensive, usually it is not suitable for the rapid test in large-scale environmental epidemiologic surveys. The purpose of this study is to develop a simple and rapid method for estimating TBARS levels by using a multiple regression equation that includes TBARS levels measured with a microplate reader as an independent variable. Twelve hour urine samples were obtained from 715 subjects. The concentration of TBARS was measured at three different wavelengths (fluorescence: ${\lambda}-_{ex}$ 530 nm and ${\lambda}-_{em}$ 550 nm; ${\lambda}-_{ex}$ 515 nm and ${\lambda}-_{em}$ 553 nm; and absorbance: 532 nm) using microplate reader as well as HPLC. 500 samples were used to develop a regression equation, and the remaining 215 samples were used to evaluate the validity of the regression analysis. The induced multiple regression equation is as follows: TBARS level (${\mu}M$) = -0.282 + 1.830 ${\times}$ (TBARS level measured with a microplate reader at the fluorescence wavelengths ${\lambda}-_{ex}$ 530 nm and ${\lambda}-_{em}$ 550 nm, ${\mu}M$) -0.685 ${\times}$ (TBARS level measured with a microplate reader at the fluorescence wavelengths ${\lambda}-_{ex}$ 515 nm and ${\lambda}-_{em}$ 553 nm, ${\mu}M$) + 0.035 ${\times}$ (TBARS level measured with a microplate reader at the absorbance wavelength 532 nm, ${\mu}M$). The estimated TBARS levels showed a better correlation with, and are closer to, the corresponding TBARS levels measured by HPLC compared to the values obtained by the microplate method. The TBARS estimation method reported here is simple and rapid, and that is generally in concordance with HPLC measurements. This method might be a useful tool for monitoring of urinary TBARS level in environmental epidemiologic surveys with large sample sizes.