• Title/Summary/Keyword: Statistical moment

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Dose and Image Assessment according to Radiologic Factors Variation at Digital Humerus X-ray Examination (디지털 환경에서 Humerus 검사 시 촬영인자 변화에 따른 선량 및 화질 평가)

  • Kim, Seong Min;Hong, Seon Sook;Lee, Kwan Sup;Ha, Dong Yun
    • Korean Journal of Digital Imaging in Medicine
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    • v.14 no.2
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    • pp.1-8
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    • 2012
  • Purpose : We aim at presenting the optimum radiologic factor through the evaluation of dose variation and of image quality through the use of a grid in Humerus examination and the change of dose because of the change of radiologic factor. Materials and Methods : We divided it in 3 cases: when using a grid or not and when using IP(Image Plate) in a digital system. Also, as fixing kVp to 70kVp it changed mAs, and fixing mAs to 10 it changed kVp, we put up resolution chart and Burger rose phantom on the acrylic phantom of 7cm (the same level of Humerus) to evaluate the dose and image. We used Image J program to evaluate the quantitative resolution of the obtained image, and made the qualitative evaluation and statistical analysis of the image saved in PACS for 20 radiologic technologist with more than 10 years of experience in order of evaluate its contrast. We used SPSS10(SPSS Inc. Chicago, Illinois) for statistical analysis. Results : We observed the analytic result of resolution by the change of kVp that it was $4.539dGycm^2$ in 60kVp and $757.472dGycm^2$ in 75kVp, which increased about 64.6% of dose, while for the resolution it had the pixel value 30.7% better with 851 in 60kVp than 651 in 75kVp. Also, we analyzed the result of resolution by the change of mAs that it was $3.106dGycm^2$ in 5mAs, and $12.470dGycm^2$ in 20mAs, which increased about 400% of dose, while for the resolution DR had 678 in 5mAs, and 724 in 20mAs that increased about 6.8% of resolution. We made the qualitative evaluation of contrast by the change of kVp that DR showed the higher quality than CR, but the contrast by the change of kVp had no special different at the moment of visual evaluation, nor statistically significant difference(P>0.05). We observed the qualitative evaluation of contraste by the change of mAs that the contrast increased as DR increased mAs, and had statistically significant difference(P<0.05). On the other hand, CR had no significant difference for more than 10mAs nor statistically significant difference(P>0.05). Conclusion : In case of some patients with radiographic exposure by the repeated examination such as emergent patient or Follow up patient, they are considered to try to limit the use of a grid, to set kVp under 65kVp in fixed mode, to select less than 10mAs and to reduce the possibility of patient being bombed.

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Reliability-Based Design Optimization Using Enhanced Pearson System (개선된 피어슨 시스템을 이용한 신뢰성기반 최적설계)

  • Kim, Tae-Kyun;Lee, Tae-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.2
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    • pp.125-130
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    • 2011
  • Since conventional optimization that is classified as a deterministic method does not consider the uncertainty involved in a modeling or manufacturing process, an optimum design is often determined to be on the boundaries of the feasible region of constraints. Reliability-based design optimization is a method for obtaining a solution by minimizing the objective function while satisfying the reliability constraints. This method includes an optimization process and a reliability analysis that facilitates the quantization of the uncertainties related to design variables. Moment-based reliability analysis is a method for calculating the reliability of a system on the basis of statistical moments. In general, on the basis of these statistical moments, the Pearson system estimates seven types of distributions and determines the reliability of the system. However, it is technically difficult to practically consider the Pearson Type IV distribution. In this study, we propose an enhanced Pearson Type IV distribution based on a kriging model and validate the accuracy of the enhanced Pearson Type IV distribution by comparing it with a Monte Carlo simulation. Finally, reliability-based design optimization is performed for a system with type IV distribution by using the proposed method.

A Comparison Analysis among Structural Equation Modeling (AMOS, LISREL and PLS) Using the Same Data (동일 데이터를 이용한 구조방정식 툴 간의 비교분석)

  • Nam, Soo-tai;Kim, Do-goan;Jin, Chan-yong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.7
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    • pp.978-984
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    • 2018
  • Structural equation modeling is pointing to statistical procedures that simultaneously perform path analysis and confirmatory factor analysis. Today, this statistical procedure is an essential tool for researchers in the social sciences. There are as AMOS, LISREL and PLS representative tools that can perform structural equation modeling analysis. AMOS provides a convenient graphical user interface for beginners to use. PLS has the advantage of not having a constraint on normal distribution as well as a graphical user interface. Therefore, we compared and analyzed the three most commonly used tools (applications) in social sciences. Based on structural equation modeling, confirmatory factor analysis was performed using the IBM AMOS Ver. 23, the LISREL 8.70 and the SmartPLS 2.0. The comparative results show that LISREL has the highest explanatory power of dependent variables than other analytical tools. The path coefficients and T-values presented by the analysis results showed similar results for all three analysis tools. This study suggests practical and theoretical implications based on the results.

Lower Limbs Muscle Comparative Research for Verification Effect of Rehabilitation Training Program of Total Hip Arthroplasty (재활운동 프로그램에 참가한 엉덩인공관절 수술자의 하지근력 변화에 대한 비교연구)

  • Jin, Young-Wan
    • Journal of Life Science
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    • v.20 no.4
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    • pp.543-548
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    • 2010
  • The purpose of this study was to examine the differences in kinetics between 6 months of rehabilitation training and 12 months of rehabilitation training after total hip arthroplasty. 10 unilateral THA participants performed kinetic tests. Three dimensional kinematics and hip flexors and abductors electromyography (EMG) were collected during each trial. T-test was used for statistical analysis (p<0.05). There was no significant difference in EMG data between the two groups, but the mean comparison EMG data was higher in the 12 months rehabilitation training group than the 6 months rehabilitation training group. The moment value was found with motion-dependent interaction analyzing method which was used by Feltner and Dapena. There was no significant difference between moment values of the two groups. There was no significant difference between ground reaction forces of the two groups; however, there were some differences shown in Fz (vertical reaction force) between the two groups ($892{\pm}104\;N$, $820{\pm}87\;N$). The first peak impact force was about 9% lower in the 12 months group compared to the 6 months group. The second peak active force was nearly equal between the two groups. More research is necessary to determine exactly what constitutes optimal rehabilitation training biomechanics for patients with total hip arthroplasty.

Biomechanical and Physiological Comparative Analysis of the Single-Radius Knee Arthroplasty Systems and Multi-Radius Knee Arthroplasty Systems (무릎인공관절 단축범위(Single-Radius) 수술자와 다축범위(Multi-Radius) 수술자의 운동역 학적 및 운동생리학적 비교분석)

  • Jin, Young-Wan;Kwak, Yi-Sub
    • Journal of Life Science
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    • v.18 no.11
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    • pp.1532-1537
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    • 2008
  • The purpose of this study was to investigate the effect of different arthroplasty designs on knee kinematic and lower limb muscular activation for up-stair and down-stair movement. 3-D video analysis of whole body and joint kinematics and EMG analysis of quadriceps and hamstrings were conducted. One-way ANOVAs were used for statistical analyses (p=0.05). The single-radius group exhibited more arthroplasty limb quadriceps EMG and hamstring coactivation EMG than the multi-radius group. Single-radius demonstrated more abduction angular displacement and reached peak abduction earlier than the multi-radius arthroplasty limb. The single- radius the percent body fat showed similar values in the Elderly, Single and Multi-radius group among the periods, however Control group was Lowered among the periods. Single-radius group limb also increased the quadriceps muscle activation level to produce more knee extension moment to compensate for the short quadriceps moment arm. Resting metabolic rate was significantly increased in control group in the period of LI. Energy expenditure was extremely increased in all groups except control group among the periods. We can say this is the exercise effects.

Characteristic of Raindrop Size Distribution Using Two-dimensional Video Disdrometer Data in Daegu, Korea (2차원 광학 우적계 자료를 이용한 대구지역 우적크기분포 특성 분석)

  • Bang, Wonbae;Kwon, Soohyun;Lee, GyuWon
    • Journal of the Korean earth science society
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    • v.38 no.7
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    • pp.511-521
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    • 2017
  • This study analyzes Two-dimensional video disdrometer (2DVD) data while summer 2011-2012 in Daegu region and compares with Marshall and Palmer (MP) distribution to find out statistical characteristics and characteristics variability about drop size distribution (DSD) of Daegu region. As the characterize DSD of Daegu region, this study uses single moment parameters such as rainfall intensity (R), reflectivity factor (Z) and double moment parameters such as generalized characteristics number concentration ($N{_0}^{\prime}$) and generalized characteristics diameter ($D{_m}^{\prime}$). Also, this study makes an assumption that DSD function can be expressed as general gamma distribution. The results of analysis show that DSD of Daegu region has ${\log}_{10}N{_0}^{\prime}=2.37$, $D{_m}^{\prime}=1.04mm$, and c =2.37, ${\mu}=0.39$ on average. When the assumption of MP distribution is used, these figures then end up with the different characteristics; ${\log}_{10}N{_0}^{\prime}=2.27$, $D{_m}^{\prime}=0.9mm$, c =1, ${\mu}=1$ on average. The differences indicate liquid water content (LWC) of Daegu distribution is generally larger than MP distribution at equal Z. Second, DSD shape of Daegu distribution is concave upward. Other important facts are the characteristics of Daegu distribution change when Z changes. DSD shape of Daegu region changes concave downward (c =2.05~2.55, ${\mu}=0.33{\sim}0.77$) to cubic function-like shape (c =3.0, ${\mu}=-0.13{\sim}-0.33$) at Z > 45 dBZ. 35 dBZ ${\leq}$ Z > 45 dBZ group of Daegu distribution has characteristics similar to maritime cluster of diverse climate DSD study. However, Z > 45 dBZ group of Daegu distribution has a difference from the cluster.

A Study of Improvement of School Health in Korea (학교보건(學校保健)의 개선방안(改善方案) 연구(硏究))

  • Lee, Soo Hee
    • Journal of the Korean Society of School Health
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    • v.1 no.2
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    • pp.118-135
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    • 1988
  • This study is designed to analyze the problems of health education in schools and explore the ways of enhancing health education from a historical perspective. It also shed light on the managerial aspect of health education (including medical-check-up for students disease management. school feeding and the health education law and its organization) as well as its educational aspect (including curriculum, teaching & learning, and wishes of teachers). At the same time it attempted to present the ways of resolving the problems in health education as identified her. Its major findings are as follows; I. Colculsion and Summary 1. Despite the importance of health education, the area remains relatively undeveloped. Students spend a greater part of their time in schools. Hence the government should develop a keener awareness of the importance of health education and invest more in it to ensure a healthy, comfortable life for students. 2. At the moment the outcomes of medical-check-up for students, which constitutes the mainstay of health education, are used only as statistical data to report to the relevant authorities. Needless to say they should be used to help improve the wellbeing of students. Specifically, nurse-teachers and home-room teachers should share the outcomes of medical-check-up to help the students wit shortcomings in growth or development or other physical handicaps more clearly recognize their problems and correct them if possible. 3. In the area of disease management, 62.6, 30.3 and 23.0 percent of primary, middle, and highschool students, respectively, were found to suffer from dental ailments. By contrast 2.2, 7.8, and 11.5 percent of primary, middle and highschool students suffered from visual disorders. The incidence of dental ailments decreases while that of visual impairments increases as students grow up. This signifies that students are under tremendous physical strain in their efforts to be admitted by schools of higher grade. Accordingly the relevant authorities should revise the current admission system as well as improve lighting system in classrooms. 4. Budget restraints have often been cited as a major bottleneck to the expansion of school feeding. Nevertheless it should be extended at least, to all primary schools even at the expense of parents to ensure the sound growth of children by improving their diet. 5. The existing health education law should be revised in such a way as to better meet the needs of schools. Also the manpower for health education should be strengthened. 6. Proper curriculum is essential to the effective implementation of health education. Hence it is necessary to remove those parts in the current health education curriculum that overlaps with other subjects. It is also necessary to make health education a compulsory course in teachers' college at the same time the teachers in charge of health education should be given an in-service training. 7. Currently health education is being taught as part of physical education, science, home economics or other courses. However these subjects tend to be overshadowed by English, mathematics, and other subjects which carry heavier weight in admission test. It is necessary among other things, to develop an educational plan specifying the course hours and teaching materials. 8. Health education is carried out by nurse-teachers or home-room teachers. In connection with health education, they expressed the hope that health education will be normalized with newly-developed teaching material, expanded opportunity for in-service training and increased budget, facilities and supply of manpower. These are the mainpoints that the decision-makers should take into account in the formation of future policy for health education. II. Recommendations for the Improvement of Health Education 1. Regular medical check-up for students, which now is the mainstay of health education, should be used as educational data in an appropriate manner. For instance the records of medical check-up could be transferred between schools. 2. School feeding should be expanded at least in primary schools at the expense of the government or even parents. It will help improve the physical wellbeing of youths and the diet for the people. 3. At the moment the health education law is only nominal. Hence the law should be revised in such a way as to ensure the physical wellbeing of students and faculty. 4. Health education should be made a compulsory course in teachers' college. Also the teachers in service should be offered training in health education. 5. The curriculum of health education should be revised. Also the course hours should be extended or readjusted to better meet the needs of students. 6. In the meantime the course hours should be strictly observed, while educational materials should be revised in no time. 7. The government should expand its investment in facilities, budget and personnel for health education in schools at all levels.

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How Customer Experience Management in the Hotel Industry can Lead to a Willingness to Pay More (호텔 기업의 고객경험관리(CEM)는 기꺼이 더 지불하게 하는가?)

  • Choi, Wook-Hee
    • Culinary science and hospitality research
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    • v.22 no.7
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    • pp.267-280
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    • 2016
  • Customer Experience Management (CEM) appeared as a complementary solution to overcome CRM limitations. CEM enhances profitability through building long-term relations with customers by understanding their experiences. This study aims at investigating the impact of customer experience quality on the willingness to pay more through customer satisfaction in the hotel businesses. The survey for this study was carried out on customers who had domestic hotel experience s within the last 6 months. Out of the 306 questionnaires retrieved, 225 valid responses were used for the empirical analysis that utilizied the statistical package programs SPSS 18.0 and AMOS 18.0. The research findings may be summarized as follows. First, as an outcome of the research hypothesis that each component of customer experience management would influence satisfaction, 'the peace of mind' & 'the moment of truth' were shown to have a significantly positive (+) impact on it. On the other hand, 'the product experience' was shown not to significantly influence it in a positive (+) way. Second, as an outcome of the research hypothesis that satisfaction would influence willingness to pay more. From the findings of the study, theoretical implications are as follows. It can be predicted that customer experience management will likely make customers more profitable because customers are willing to pay more with a sense of loyalty built through satisfaction of the hotel industry. In the practical implications, the dimension of experience quality examined by the study can be used as an index to measure and manage customer experience in the hotel industry.

Effect of Mouthguard on Tooth Distortion During Clenching (이악물기 시 발생되는 치아변형에 대한 구강보호장치의 역할)

  • Lee, Yun;Choi, Dae-Gyun;Kwon, Kung-Rock;Lee, Richard Sung-Bok;Noh, Kwan-Tae
    • Journal of Dental Rehabilitation and Applied Science
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    • v.26 no.4
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    • pp.405-417
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    • 2010
  • Previous studies have already shown that mouthguard is effective in protecting jaw bone, teeth and oral tissue against sports trauma. However, other than severe trauma, repetitive force, such as disorders like clenching, cause teeth or oral tissue damage. These kinds of disorders usually present pathologic attrition in the posterior teeth, resorption in alveolar bone, loss of teeth and destruction of occlusion. Wearing a mouthguard is believed to be effective in preventing these disorders. But its effect is not examined thoroughly enough. The purpose of this study is to identify whether mouthguard is effective in reducing strain caused by clenching. Mandibular first molars in the normal occlusal relationship without any history of dental treatment were chosen. Biaxial type strain gauge was placed on the buccal surface of the tooth. Having maximum occlusal force, measured by load cell, as a standard, clenching intensity were divided into three stages; moment of slightly tooth contact, medium bite force (50% of maximum bite force), maximum bite force. Strain occurring in dentition in each stage with and without mouthguard was measured. Changes in strain (on dentition) between each stage and difference in strain, between with or without mouthguard were recorded by PCD-300 analyzer and PCD-30 soft ware. The data was statistically analyzed by Wilcoxon signed rank test. The following results were drawn; Without mouthguard, strain given on dentition increased as the clenching force increased. With mouthguard, strain given on dentition also increased as the clenching force increased. With mouthguard, strain decreased, in all cases of clenching force stages. Data on the moment of slightly tooth contact stage, had no statistical significance. However, with mouthguard, 50-90% of decrease in strain could be obtained in maximum occlusal force, compared to the group without mouthguard. Mouthguard decreased the strain on the dentition, caused by clenching. Therefore, mouthguard seems to be effective in preventing damage on dentition, by acting against clenching, which occurs both consciously and unconsciously during sports activities.

A Reliability Analysis of Shallow Foundations using a Single-Mode Performance Function (단일형 거동함수에 의한 얕은 기초의 신뢰도 해석 -임해퇴적층의 토성자료를 중심으로-)

  • 김용필;임병조
    • Geotechnical Engineering
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    • v.2 no.1
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    • pp.27-44
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    • 1986
  • The measured soil data are analyzed to the descriptive statistics and classified into the four models of uncorrelated-normal (UNNO), uncorrelated-nonnormal (VNNN), correlatedonnormal(CONN), and correlated-nonnormal(CONN) . This paper presents the comparisons of reliability index and check points using the advanced first-order second-moment method with respect to the four models as well as BASIC Program. A sin91e-mode Performance function is consisted of the basic design variables of bearing capacity and settlements on shallow foundations and input the above analyzed soil informations. The main conclusions obtained in this study are summarized as follows: 1. In the bearing capacity mode, cohesion and bearing-capacity factors by C-U test are accepted for normal and lognormal distribution, respectively, and negatively low correlated to each other. Since the reliability index of the CONN model is the lowest one of the four model, which could be recommended a reliability.based design, whereas the other model might overestimate the geotechnical conditions. 2. In the case of settlements mode, the virgin compression ratio and preccnsolidation pressure are fitted for normal and lognormal distribution, respectively. Constraining settlements to the lower ones computed by deterministic method, The CONN model is the lowest reliability of the four models.

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