• Title/Summary/Keyword: statistical analysis.

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POLYMERIZATION SHRINKAGE OF COMPOSITE RESINS CURED BY VARIABLE LIGHT INTENSITIES (가변 광도 중합에 따른 복합레진의 중합수축에 관한 연구)

  • Lim, Mi-Young;Cho, Kyung-Mo;Hong, Chan-Ui
    • Restorative Dentistry and Endodontics
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    • v.32 no.1
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    • pp.28-36
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    • 2007
  • The purpose of this study was to compare the effect of exponential curing method with conventional curing and soft start curing method on polymerization shrinkage of composite resins. Three brands of composite resins (Synergy Duo Shade, Z250, Filtek Supreme) and three brands of light curing units (Spectrum 800, Elipar Highlight, Elipar Trilight) were used. 40 seconds curing time was given. The shrinkage was measured using linometer for 90 seconds. The effect of time on polymerization shrinkage was analysed by one-way ANOVA and the effect of curing modes and materials on polymerization shrinkage at the time of 90s were analysed by two-way ANOVA. The shrinkage ratios at the time of 20s to 90s were taken and analysed the same way. The results were as follows : 1. All the groups except Supreme shrank almost within 20s Supreme cured by soft start and exponential curing had no further shrinkage after 30s (p < 0.05). 2. Statistical analysis revealed that polymerization shrinkage varied among materials (p = 0.000) and curing modes (p = 0.003). There was no significant interaction between material and curing mode. 3. The groups cured by exponential curing showed the statistically lower polymerization shrinkage at 90s than the groups cured by conventional curing and soft start curing (p < 0.05). 4. The initial shrinkage ratios of soft start and exponential curing were statistically lower than conventional curing (p < 0.05). From this study, the use of low initial light intensities may reduce the polymerization rate and, as a result, reduce the stress of polymerization shrinkage.

Development of Evaluation Indicators for a Children's Dietary Life Safety Index in Korea (한국 어린이 식생활 안전지수의 평가 지표 개발)

  • Chung, Hae-Rang;Kwak, Tong-Kyung;Choi, Young-Sun;Kim, Hye-Young P.;Lee, Jung-Sug;Choi, Jung-Hwa;Yi, Na-Young;Kwon, Se-Hyug;Choi, Youn-Ju;Lee, Soon-Kyu;Kang, Myung-Hee
    • Journal of Nutrition and Health
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    • v.44 no.1
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    • pp.49-60
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    • 2011
  • This study was performed to develop a children's dietary life safety index required by the Special Act on Safety Management of Children's Dietary Life enacted in 2009. An analytical hierarchy process was used to obtain initial weights of dietary life safety evaluation indicators. The Delphi method was applied to develop the weights along with 98 food and nutrition professionals. Three representative policy indicators, nine strategy indicators, 11 main evaluation indicators, and 20 detailed evaluation indicators were selected for the children's dietary life safety assessment. Three policy indicators and nine strategy indicators were the following: children's food safety indicator (support level of children' safety, safety management level of children's favorite foods, and safety management level of institutional food service), children's nutrition safety indicator (management level of missing meals and obesity, nutrition management level of children's favorite foods, and nutrition management level of institutional food service), and children's perception and practice level indicator ("Dietary Life Law" perception level, perception, and practice level for dietary life safety management, perception, and practice level for nutrition management). Weights of 40%, 40%, and 20% were given for the three representative policy indicators. The relative importance of nine strategic indicators, which were determined by the Delphi method is as follows: For children’s food safety, support level of children's safety, safety management level of children's favorite foods, and safety management level of institutional food service were given weights of 12%, 9%, and 19%, respectively. For children's nutrition safety, the missing meals and obesity management level, nutrition management level of children's favorite foods, and the nutrition management level of institutional food service were given weights of 13%, 11%, and 16%, respectively. The "Dietary Life Law" perception level, perception and practice level of dietary life safety management, and perception and practice level of nutrition management were given weights of 4%, 7%, and 9%, respectively.

Development of NQ-E, Nutrition Quotient for Korean elderly: item selection and validation of factor structure (노인 대상 영양지수 개발 : 평가항목 선정과 구성 타당도 검증)

  • Chung, Min-Jae;Kwak, Tong-Kyung;Kim, Hye-Young;Kang, Myung-Hee;Lee, Jung-Sug;Chung, Hae Rang;Kwon, Sehyug;Hwang, Ji-Yun;Choi, Young-Sun
    • Journal of Nutrition and Health
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    • v.51 no.1
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    • pp.87-102
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    • 2018
  • Purpose: The purpose of this study was to develop a valid instrument for measuring the dietary quality and behaviors of Korean elderly. Methods: The development of the Nutrition Quotient for Elderly (NQ-E) was conducted in three steps: item generation, item reduction, and validation. The 41 items of the NQ-E checklist were derived from a systematic literature review, expert in-depth interviews, statistical analyses of the fifth Korean National Health and Nutrition Examination Survey data, and national nutrition policies and recommendations. Pearson's correlation was used to determine the level of agreement between the questionnaires and nutrient intake level, and 24 items were selected for a nationwide survey. A total of 1,000 nationwide elderly subjects completed the checklist questionnaire. The construct validity of the NQ-E was assessed using confirmatory factor analysis, LISREL. Results: The nineteen checklist items were used as final items for NQ-E. Checklist items were composed of four-factors: food behavior (6 items), balance (4 items), diversity (6 items), and moderation (3 items). The standardized path coefficients were used as the weights of the items. The NQ-E and four-factor scores were calculated according to the obtained weights of the questionnaire items. Conclusion: NQ-E would be a useful tool for assessing the food behavior and dietary quality of the elderly.

The Need for Paradigm Shift in Semantic Similarity and Semantic Relatedness : From Cognitive Semantics Perspective (의미간의 유사도 연구의 패러다임 변화의 필요성-인지 의미론적 관점에서의 고찰)

  • Choi, Youngseok;Park, Jinsoo
    • Journal of Intelligence and Information Systems
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    • v.19 no.1
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    • pp.111-123
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    • 2013
  • Semantic similarity/relatedness measure between two concepts plays an important role in research on system integration and database integration. Moreover, current research on keyword recommendation or tag clustering strongly depends on this kind of semantic measure. For this reason, many researchers in various fields including computer science and computational linguistics have tried to improve methods to calculating semantic similarity/relatedness measure. This study of similarity between concepts is meant to discover how a computational process can model the action of a human to determine the relationship between two concepts. Most research on calculating semantic similarity usually uses ready-made reference knowledge such as semantic network and dictionary to measure concept similarity. The topological method is used to calculated relatedness or similarity between concepts based on various forms of a semantic network including a hierarchical taxonomy. This approach assumes that the semantic network reflects the human knowledge well. The nodes in a network represent concepts, and way to measure the conceptual similarity between two nodes are also regarded as ways to determine the conceptual similarity of two words(i.e,. two nodes in a network). Topological method can be categorized as node-based or edge-based, which are also called the information content approach and the conceptual distance approach, respectively. The node-based approach is used to calculate similarity between concepts based on how much information the two concepts share in terms of a semantic network or taxonomy while edge-based approach estimates the distance between the nodes that correspond to the concepts being compared. Both of two approaches have assumed that the semantic network is static. That means topological approach has not considered the change of semantic relation between concepts in semantic network. However, as information communication technologies make advantage in sharing knowledge among people, semantic relation between concepts in semantic network may change. To explain the change in semantic relation, we adopt the cognitive semantics. The basic assumption of cognitive semantics is that humans judge the semantic relation based on their cognition and understanding of concepts. This cognition and understanding is called 'World Knowledge.' World knowledge can be categorized as personal knowledge and cultural knowledge. Personal knowledge means the knowledge from personal experience. Everyone can have different Personal Knowledge of same concept. Cultural Knowledge is the knowledge shared by people who are living in the same culture or using the same language. People in the same culture have common understanding of specific concepts. Cultural knowledge can be the starting point of discussion about the change of semantic relation. If the culture shared by people changes for some reasons, the human's cultural knowledge may also change. Today's society and culture are changing at a past face, and the change of cultural knowledge is not negligible issues in the research on semantic relationship between concepts. In this paper, we propose the future directions of research on semantic similarity. In other words, we discuss that how the research on semantic similarity can reflect the change of semantic relation caused by the change of cultural knowledge. We suggest three direction of future research on semantic similarity. First, the research should include the versioning and update methodology for semantic network. Second, semantic network which is dynamically generated can be used for the calculation of semantic similarity between concepts. If the researcher can develop the methodology to extract the semantic network from given knowledge base in real time, this approach can solve many problems related to the change of semantic relation. Third, the statistical approach based on corpus analysis can be an alternative for the method using semantic network. We believe that these proposed research direction can be the milestone of the research on semantic relation.

The Oral Health Behaviors for Children and Teachers by Teacher-Supervised Toothbrushing in Community Child Center (지역아동센터 교사의 칫솔질 지도여부에 따른 아동과 교사의 구강보건행태)

  • Shin, Sun-Jung;Jang, Jung-Yoo;Kim, Chang-Hee
    • Journal of dental hygiene science
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    • v.12 no.6
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    • pp.572-582
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    • 2012
  • The purpose of this research was to compare the oral health behaviors for children and teachers in toothbrushing facilities installed community child center related with teacher-supervised toothbrushing. This research was follow-up study from the Korean Dental Hygienists Association third project '2010 program of making of the diamond tooth'. 266 child support teachers were invited and 201 were included in the study (response rate: 75.6%). Statistical analysis conducted using PASW ver. 18.0 for Windows. The difference on the distribution of independent variables related with teacher-supervised toothbrushing was verified with chi-square test. The results of this research could be summarized as follows: The children in the teacher-supervised toothbrushing community child center, the practice rate of toothbrushing was higher than the children in the non-supervised toothbrushing community child center (p<0.05). Teachers offered children one of snacks and drinks per day independently of teacher-supervised toothbrushing (p>0.05). Most of participated teachers accepted to be responsible for oral health of children (73.4%) and demanded that improve facilities for a toothbrushing in community child center (77.2%). In conclusion, this study suggests that a programme of daily teacher-supervised toothbrushing can be effectively targeted into community child center.

A Study on the Stressors of Dental Hygienists and Student Hygienists during the Clinical Practice by Medical Center Type (임상실습 시 병원형태별 치과위생사와 실습학생이 경험하게 되는 스트레스 요인에 관한 연구)

  • Jang, Sung-Yeon;Kwon, Soon-Bok;Yang, Seung-Kyeong
    • Journal of dental hygiene science
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    • v.12 no.6
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    • pp.682-688
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    • 2012
  • This study investigates the stressors of dental hygienists and student hygienists during the bedside training by the medical center type. The survey is based on some dental hygienists who are working for dental college hospitals, general hospitals, dental hospitals and dental clinics in Seoul and Gyeonggi area which the Clinical Practice of dental hygienics students is under way in. Included are the students who are studying dental hygienics at Kyungbok University and have taken the bedside training in dental college hospitals, general hospitals, dental hospitals and dental clinics. A statistical analysis shows the following results using SPSS program. By medical center type, dental hygienists described the clinical practice of students as relatively satisfying. It also found that there is a positive correlation between stress zones, and they feel most stressed in the "Role and Activity" zone. Student hygienists felt relatively satisfied with the bedside training, and there is a positive correlation between stress zones except "Practice". It found students, who have taken the bedside training in all types of medical centers except dental clinics, felt most stressed in "Environment". It also found that students who have taken the bedside training in dental clinics felt most stressed in "Role and Activity". In conclusion, most of the dental hygienists are satisfied with students' clinical practice by pattern of hospital. Positive correlation was shown between stress factors. Behavior and attitude and ideal and value are high in stress in college dental hospitals, role and activity and treatment fields are high in stress in dental hospital, and interpersonal relationships are high in stress in dental clinics.

The Effect of Perfectionism on Stress and Anxiety during Scaling Practice (완벽주의가 스케일링 실습 시 실습불안과 스트레스에 미치는 영향)

  • Lim, Soon-Ryun;Woo, Hee-Sun
    • Journal of dental hygiene science
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    • v.9 no.2
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    • pp.161-167
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    • 2009
  • The purpose of this Study was to examine the effect of perfectionism on stress and anxiety during scaling practice in an effort to find efficient way of helping students with getting good skills. The subjects in this study were students who practiced a scaling at the oral hygiene practice lab in the Department of dental hygiene in S college from May 1 to May 31, 2008. They were divided into four groups based on their subscales of perfectionism : mixed perfectionist group, achievement striving perfectionist group, failure avoidance perfectionist group and non-perfectionist group. The measurements used were Two-Dimensional Perfectionism Scale, Stress level, Trait anxiety, State anxiety. There were no significant differences in the stress level before practice between 4 groups. There were significant differences in trait anxiety, state anxiety, total anxiety before scaling practice between 4 groups. However, these results were due to differences between mixed perfectionist group and non-perfectionist group. After practice, total anxiety was decreased from 93.71 to 89.66 and state anxiety was decreased from 45.49 to 43.38. These results were statistically significant. In order to investigate the influence of achievement striving factor and failure avoidance factor on the change of state anxiety during the scaling practice Standard Multiple Regression were employed for the statistical analysis. Failure avoidance factor was related with the increase of state anxiety during the scaling practice. So leachers have to give all effort to reduce the anxiety of students during scaling practice and provide students with motivation of achievement.

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Clinical Efficacy of Bunny Multifocal Intraocular Lens after Cataract Surgery (버니 다초점인공수정체의 임상적 효용성)

  • Cho, Myung Ho;Park, Jae Yeong;Park, Byung Gun;Lee, Jong Soo
    • Journal of The Korean Ophthalmological Society
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    • v.59 no.12
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    • pp.1129-1136
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    • 2018
  • Purpose: To compare the postoperative clinical outcomes after cataract surgery and implantation using the BunnyLens $MF^{(R)}$ and $ReSTOR^{(R)}$ multifocal intraocular lenses. Methods: Sixty-five eyes implanted with multifocal intraocular lenses were divided into two groups involving either $ReSTOR^{(R)}$ (39 eyes) or BunnyLens $MF^{(R)}$ (26 eyes) lenses. In these two groups, the distant and near visual acuity, astigmatism, spherical equivalent, and contrast sensitivity test were examined at preoperative and postoperative 1 week, 8 weeks, and 24 weeks. We compared the clinical efficacy between the two groups before and after cataract surgery using statistical analysis. Results: The mean value of distant and near visual acuity, and spherical equivalent of both groups after intraocular lens implantation were significantly improved, compared with the preoperative values (p < 0.05), while there was no significant differences between the two groups (p > 0.05). The means of postoperative distant and near visual acuity, astigmatism, and contrast sensitivity test were not significantly different between $ReSTOR^{(R)}$ and BunnyLens $MF^{(R)}$ lenses (p > 0.05). The mean numeric error of spherical equivalent at the final postoperative 24 weeks was $-0.17{\pm}0.50$ diopters (D) for the $ReSTOR^{(R)}$ lenses and $-0.34{\pm}0.52D$ for the BunnyLens $MF^{(R)}$ lenses (p > 0.05). Conclusions: BunnyLens $MF^{(R)}$ and $ReSTOR^{(R)}$ lenses showed no significant difference in clinical efficacy, including distance and near vision, spherical equivalent error, and contrast sensitivity test after cataract surgery. However, it should be noted that BunnyLens $MF^{(R)}$ lenses had a tendency toward myopic shift compared with $ReSTOR^{(R)}$ lenses.

Study on the LOWTRAN7 Simulation of the Atmospheric Radiative Transfer Using CAGEX Data. (CAGEX 관측자료를 이용한 LOWTRAN7의 대기 복사전달 모의에 대한 조사)

  • 장광미;권태영;박경윤
    • Korean Journal of Remote Sensing
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    • v.13 no.2
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    • pp.99-120
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    • 1997
  • Solar radiation is scattered and absorbed atmospheric compositions in the atmosphere before it reaches the surface and, then after reflected at the surface, until it reaches the satellite sensor. Therefore, consideration of the radiative transfer through the atmosphere is essential for the quantitave analysis of the satellite sensed data, specially at shortwave region. This study examined a feasibility of using radiative transfer code for estimating the atmospheric effects on satellite remote sensing data. To do this, the flux simulated by LOWTRAN7 is compared with CAGEX data in shortwave region. The CAGEX (CERES/ARM/GEWEX Experiment) data provides a dataset of (1) atmospheric soundings, aerosol optical depth and albedo, (2) ARM(Aerosol Radiation Measurement) radiation flux measured by pyrgeometers, pyrheliometer and shadow pyranometer and (3) broadband shortwave flux simulated by Fu-Liou's radiative transfer code. To simulate aerosol effect using the radiative transfer model, the aerosol optical characteristics were extracted from observed aerosol column optical depth, Spinhirne's experimental vertical distribution of scattering coefficient and D'Almeida's statistical atmospheric aerosols radiative characteristics. Simulation of LOWTRAN7 are performed on 31 sample of completely clear days. LOWTRAN's result and CAGEX data are compared on upward, downward direct, downward diffuse solar flux at the surface and upward solar flux at the top of the atmosphere(TOA). The standard errors in LOWTRAN7 simulation of the above components are within 5% except for the downward diffuse solar flux at the surface(6.9%). The results show that a large part of error in LOWTRAN7 flux simulation appeared in the diffuse component due to scattering mainly by atmispheric aerosol. For improving the accuracy of radiative transfer simulation by model, there is a need to provide better information about the radiative charateristrics of atmospheric aerosols.

The Effects on the Blood Lipid Profiles and Body Fat by Long Term Administration of Red Ginseng Product (장기간 홍삼복방제 투여가 혈중 지질 및 체지방 변화에 미치는 영향)

  • Kim, Sung-Soo;Park, Ho-Yoon;Byun, Yong-Hyun;Hwang, Bu-Geun;Lee, Jae-Hyun;Shim, Young-Jae;Park, Chae-Kyu;Park, Myung-Han;Yang, Jai-Won
    • Journal of Ginseng Research
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    • v.26 no.2
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    • pp.67-73
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    • 2002
  • This study was done in order to evaluate the of effects on the blood lipid profiles, the body weight and body fat in 28 healthy female volunteers who had over 30% body fat by the long term intake of red ginseng product. Subjects were divided into four groups (placebo group n=7, red ginseng product group; n=7, exorcise group; n=7, exercise & red ginseng product group; n=7). Blood sampling and measuring of the body fat were taken by pre-treatment, 3 weeks, and after 12 weeks. Statistical techniques for data analysis were applied one-way ANOVA and repeated measures ANOVA. The 5% level of significance was used as the critical level for this study. In summary of results, total cholesterol, triglyceride and low density lipoproprotein cholesterol were reduced in three groups (red ginseng product group, p<0.001, exercise group, p<0.01 ; exercise & red ginseng product group, p<0.001) except placebo group. HDL-C was improved in three groups (red ginseng product group, p<0.05; exercise group, p<0.01; exercise & red ginseng product group, p<0.001) except placebo group. Body weight, percent body fat and body fat mass were reduced in three groups (red ginseng product group, p<0.01, exercise group, p<0.01 ; exercise & red ginseng product group, p<0.001) except placebo group. Finally, lean body mass was improved in three groups (red ginseng product group, p<0.05; exercise group, p<0.01; exercise & red ginseng product group, p<0.001) except placebo group.