• Journal of Biosystems Engineering
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• 제36권1호
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• pp.40-47
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• 2011

Image analysis algorithm for the quality evaluation of ginseng seedling was investigated. The images of ginseng seedling were acquired with a color CCD camera and processed with the image analysis methods, such as binary conversion, labeling, and thinning. The processed images were used to calculate the length and weight of ginseng seedlings. The length and weight of the samples could be predicted with standard errors of 0.343 mm, and 0.0214 g respectively, $R^2$ values of 0.8738 and 0.9835 respectively. For the evaluation of the three quality grades of Gab, Eul, and abnormal ginseng seedlings, features from the processed images were extracted. The features combined with the ratio of the lengths and areas of the ginseng seedlings efficiently differentiate the abnormal shapes from the normal ones of the samples. The grade levels were evaluated with an efficient pattern recognition method of support vector machine analysis. The quality grade of ginseng seedling could be evaluated with an accuracy of 95% and 97% for training and validation, respectively. The result indicates that color image analysis with support vector machine algorithm has good potential to be used for the development of an automatic sorting system for ginseng seedling.

• 보건행정학회지
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• 제28권4호
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• pp.369-377
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• 2018

Background: Catastrophic health expenditure (CHE) occurs when medical expenditure of a household passes over a certain ratio of household income. This research studied the effect of gender on CHE based on Korea Health Panel data. Methods: This study implemented binary logistic regression model to figure out whether gender affects CHE and how different gender groups show pattern of CHE process. With gender, age, marital status, income level, economic activity, membership of private insurance, existence of chronic disease, and self-rated health were included in the model. Results: Results showed that females faced CHE 1.5 times more than males (odds ratio, 1.241). Also, main determinants of CHE in female groups were marital status, while age and economic activity status were significant in male groups. Subgroup analysis displayed that married female under 35 years old are located in intersectionality of CHE including pregnancy and delivery, multiple health risk behaviors, mental stress, and relatively vulnerable social status due to lower income. Meanwhile, both gender above 50 years old faced remarkably high chance of CHE, which seems to be caused by complex health risk behaviors and chronic diseases. Conclusion: Such results implied not only that gender is an important determinant of CHE, but also other determinants of CHE differ according to gender, which suggests a necessity of gender-based CHE support and rescue policy.

• 한국자원식물학회지
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• 제29권3호
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• pp.322-330
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• 2016

Understanding the genetic variation among landrace collections is important for crop improvement and utilization of valuable genetic resources. The present study was carried out to analyse the genetic diversity and associated population structure of 621 foxtail millet accessions of Korean landraces using 22 EST-SSR markers. A total of 121 alleles were detected from all accessions with an average of 5.5 alleles per microsatellite locus. The average values of gene diversity, polymorphism information content, and expected heterozygosity were 0.518, 0.594, and 0.034, respectively. Following the unweighted neighbor-joining method with arithmetic mean based clustering using binary data of polymorphic markers, the genotypes were grouped into 3 clusters, and population structure analysis also separated into 3 populations. Principal coordinate analysis (PCoA) explained a variation of 13.88% and 10.99% by first and second coordinates, respectively. However, in PCoA analysis, clear population-level clusters could not be found. This pattern of distribution might be the result of gene flow via germplasm exchanges in nearby regions. The results indicate that these Korean landraces of foxtail millet exhibit a moderate level of diversity. This study demonstrated that molecular marker strategies could contribute to a better understanding of the genetic structure in foxtail millet germplasm, and provides potentially useful information for developing conservation and breeding strategies.

• 치위생과학회지
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• 제21권3호
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• pp.133-139
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• 2021

Background: Smoking in adolescence leads to an intensified addiction to nicotine when physical and mental growth has not yet been completed. With the advent of e-cigarettes, the rate of e-cigarette use among Korean adolescents has been steadily increasing. To date, studies on e-cigarettes and oral health, especially on the relationship between smoking styles and oral health in adolescents, are limited. Therefore, this study aimed to identify the risk factors for oral health problems caused by the repeated use of conventional cigarettes and e-cigarettes. Methods: This explanatory research study compared the adolescents' experiences of periodontal disease symptoms according to smoking type through a secondary analysis of the original data from the 15th Adolescent Health Behavior Survey (2019). Cross-analysis was performed to compare the smoking patterns according to the adolescents' general characteristics. Finally, a binary logistic regression analysis was performed to determine how smoking characteristics affect the adolescents' experience of periodontal disease symptoms. Results: In terms of patients' general characteristics, significant differences were observed in sex, school level, grades, household economic status, type of residence, and father's education level between adolescents who smoked conventional cigarettes alone and those who smoked both conventional cigarettes and e-cigarettes (p<0.05). After checking the factors affecting the smoking pattern and the experience of periodontal disease symptoms in adolescents, it was found that the duplicate smoking group was more likely to experience periodontal disease symptoms (odds ratio, 1.20) than the group that smoked conventional cigarettes alone (p<0.05). Conclusion: Duplicate smokers experienced more symptoms of periodontal disease than those who smoked cigarettes alone. Based on the findings of this study, smoking cessation counseling according to the smoking type and differentiated education for oral health promotion should be provided.

• 대한방사선기술학회지:방사선기술과학
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• 제33권2호
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• pp.97-107
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• 2010

연구 목적은 virtual digital test pattern method을 이용하여 REGIUS 150 CR 시스템의 각 LUT별 프로세싱 커브를 도출하고, Dry Imager의 특성을 파악하여 CR의 영상처리 방법을 분석하는 것이다. 실험은 먼저, CR의 화상데이터에 맞게 virtual digital test pattern 파일을 만들고, 인위적으로 입력하여 virtual digital test pattern step의 변화를 통해 각 LUT(THX, ST, STM, LUM, BONE, LIN)별 프로세싱 커브를 구한다. 그리고 하드카피 이미지를 통해 Dry Imager의 프로세싱 커브도 도출한다. 마지막으로, CR 본체의 영상처리 파라미터들을 변화시켜 각각의 특성을 알아낸다. 실험 결과를 살펴보면, 입 출력 값을 통해 CR 시스템의 입력 다이나믹 레인지의 LUT별 프로세싱 커브를 구하였다. 프로세싱 커브는 모두 곡선으로 이어져 있었으며(LIN mode 제외), 각 커브마다 조금씩 차이를 보였다. 또한 Dry Imager의 프로세싱 커브는 중간부분에만 선형성이 나타났다. 그리고 프로세싱 파라미터의 G value는 기울기와, S value는 감도의 shift량과 관련된다는 것을 알 수 있었고, 선량에 따라 S value가 비례하여 변화한다는 것 또한 유추해 낼 수 있었다. 결론적으로 CR 시스템은 각 회사별로 내부 처리가 다르고, 구조 또한 복잡하기 때문에 내부 영상처리의 파악이 어렵다. 하지만 본 연구에서 사용한 virtual digital test pattern method는 CR 시스템의 내부처리 구조와 영상 파라미터의 변화에 따른 특성을 추정할 수 있으므로, 이 방법을 통해 타 장비의 CR 시스템과 Dry Imager의 전체적인 영상처리 특성을 비교, 분석 가능할 것이다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권2호
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• pp.133-142
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• 2020

Objectives: In this study, we determined the incidence and pattern of screw loosening in patients who received dental implants. Materials and Methods: Patients who received implants between January 2008 and October 2013 and completed their prosthetic rehabilitation were evaluated for the incidence, frequency, and onset of screw loosening using dental charts and radiographs. The association between each factor and screw loosening was analyzed using the chi-square test and a multivariate analysis with binary logistic regression models (P<0.05). Results: Total 1,928 implants were placed in 837 patients (448 males, 389 females), whose follow-up period after loading varied from 0.25 to 70 months (mean period, 31.5 months). Screw loosening occurred in 7.2% of implants. Most cases occurred less than six months after loading. Among those, 22.3% experienced recurrent screw loosening. Screw loosening was most common in the molar region (8.5%) and frequently associated with an implant diameter of ≥5 mm (14.2%). External implant-abutment connections (8.9%) and screw-retained implant prostheses (10.1%) showed higher incidence of problems than internal implant-abutment connections and cement-retained implants, respectively. Screw loosening was most common in implant prostheses with single crowns (14.0%). Conclusion: Within the limits of the current study, we conclude that the incidence of screw loosening differs significantly according to the position of implant placement, the type of implant and manufacturer, implant diameter, the type of implant-abutment connection, the type of retention in the implant prosthesis, and the type of implant prosthesis.

• 한국재난정보학회 논문집
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• 제18권3호
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• pp.433-443
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• 2022

연구목적: 본 논문에서는 스마트 디바이스의 높은 보급률을 활용하여 근감소증을 추정 및 예측하는 딥러닝 알고리즘을 제안과 연구를 수행한다. 연구방법: 딥러닝 학습을 위해 스마트 디바이스에 내장된 관성센서를 활용하여 실험 데이터를 수집하였다. 데이터를 수집하는 테스트용 어플리케이션 구현하여 '정상'과 '비정상'걸음과 '달리기', '낙상', '스쿼트' 자세의 5 가지 상태를 구분하여 데이터를 수집하였다. 연구결과: LSTM, CNN, RNN model 사용 시 예측 정확도를 분석했고 CNN-LSTM 융합형 모델을 활용하여 이진분류 정확도 99.87%, 다중 분류 92.30%의 정확도를 보였다. 결론: 근감소증이 있는 사람의 경우 걸음걸이의 이상이 생긴다는 점에 착안하여 스마트 디바이스를 활용한 연구를 진행하였다. 본 연구를 활용하여 근감소증으로 인해 생기는 재난안전을 강화 할 수 있을 것이다.

• Annals of Occupational and Environmental Medicine
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• 제35권
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• pp.14.1-14.10
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• 2023

Background: Shift work is known to cause changes in the circadian rhythm of the human body and adversely affect not only physical health but also mental health. Some studies have demonstrated the correlation between shift work and thyroid stimulating hormone (TSH), a hormone that changes according to the diurnal rhythm, but few studies have reported the different TSH levels according to the shift work type. This study aimed to investigate changes in TSH according to the shift work type. Methods: This study included 1,318 female workers who had a medical checkup at a university hospital in Changwon from 2015 to 2019. Shift work types were classified as non-shift work, regular 2 shifts, and irregular three shifts, and a TSH ≥ 4.2 mIU/L was defined as abnormal. A general linear model (GLM) was used to compare the TSH levels and the risk of subclinical hypothyroidism in each year, and a binary logistic analysis was performed using a generalized estimation equation (GEE) to compare the risk of subclinical hypothyroidism over the 5-year period. Results: Of the 1,318 participants included in this study, 363, 711, and 244 were non-shift, two-shift, and irregular three-shift workers, respectively. In the GEE analysis, after adjusting for age, body mass index, smoking, and alcohol consumption, the odds ratios (ORs) were 1.81 (95% confidence interval [CI]: 1.15-2.86; p = 0.011) in 2 shifts and 2.02 (95% CI: 1.23-3.32; p = 0.006) in irregular three shifts, compared to non-shift. Conclusions: Our results showed that shift work had a higher risk of subclinical hypothyroidism than non-shift work and that there was a significant difference in the risk of subclinical hypothyroidism according to the shift work type. These findings suggest that the shift work type can be considered in future thyroid function tests and evaluations.

• 미생물학회지
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• 제32권3호
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• pp.222-231
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• 1994

Saccharomyces cerevisiae에서 얻은 purine nucleoside phosphorylase (PNP)의 반응 기작을 밝히기 위해 반응속도론적 분석이 수행되어졌다. 반응기작에 PNP${\cdot}$phosphate와 PNP${\cdot}$ribose 1-phosphate의 binary complex가 형성되는 것으로 추정되어진다. Initial velocity와 product inhibition study의 결과는 반응이 ordered bi, bi reaction으로 일어난다는 것과 일치하고 있다. 두 개의 기질중 무기인산이 효소에 먼저 붙고, 그 다음에 nucleoside, 그리고 base가 효소를 떠나는 첫 번째 생성물이고 마지막으로 ribose 1-phosphate가 생성되고 효소는 원래의 상태로 돌아간다. 반응속도론적 분석에 이해 제안된 작용기작은 sulfhydryl reagents인 p-chloromercuribenzoate(PCMB) and 5,5'-dithiobisnitrobenzoate (DTNB)에 의한 효소의 불활성화에 대한 기질으 보호작용의 결과와 일치하고 있다. PNP는 ribose 1-phosphate와 phosphate에 의해 보호되지만 nucleoside나 base에 의해서는 아무런 효과과 없다는 사실은 반응 순서가 효소에 무기인산이 먼저 붙는 ordered bi, bi 기작이라는 것을 지지하고 있다. PCMB 나 DTNB에 의해 불활성화된 PNP는 dithiothreitol(DTT)에 의해서는 활성이 완전히 회복되고 2-mercaptoethanol에 의해서는 77%의 활성이 회복된다는 사실은 효소의 불활성화가 가역적이라는 것을 시사하고 있다. PCMB에 의해 불활성화된 효소는 inosine이 변화하는 기질일때 정상효소보다 높은 $K_m$과 낮은 $V_m$ 값을 보여주고 이런 현상은 DTT 처리시 원래의 상태로 돌아온다. DTNB에 의해 불활성화된 효소는 PCMB 처리시와 비슷하게 정상효소보다 높은 $V_m$ 값을 보이지만 $V_m$ 값은 큰 변화가 없다. S. cerevisiae PNP에서 발견되는 높은 무기인산의 농도에서의 하위단위체간의 음성적 협동성이 PCMB나 DTNB를 처리한 PNP에서는 보이지 않았다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권1호
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• pp.25-44
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• 2010

With the increasing popularity of mobile devices, it has become necessary to protect private information and content in these devices. Face recognition has been favored over conventional passwords or security keys, because it can be easily implemented using a built-in camera, while providing user convenience. However, because mobile devices can be used both indoors and outdoors, there can be many illumination changes, which can reduce the accuracy of face recognition. Therefore, we propose a new face recognition method on a mobile device robust to illumination variations. This research makes the following four original contributions. First, we compared the performance of face recognition with illumination variations on mobile devices for several illumination normalization procedures suitable for mobile devices with low processing power. These include the Retinex filter, histogram equalization and histogram stretching. Second, we compared the performance for global and local methods of face recognition such as PCA (Principal Component Analysis), LNMF (Local Non-negative Matrix Factorization) and LBP (Local Binary Pattern) using an integer-based kernel suitable for mobile devices having low processing power. Third, the characteristics of each method according to the illumination va iations are analyzed. Fourth, we use two matching scores for several methods of illumination normalization, Retinex and histogram stretching, which show the best and $2^{nd}$ best performances, respectively. These are used as the inputs of an SVM (Support Vector Machine) classifier, which can increase the accuracy of face recognition. Experimental results with two databases (data collected by a mobile device and the AR database) showed that the accuracy of face recognition achieved by the proposed method was superior to that of other methods.