• Title/Summary/Keyword: Nonparametric statistics

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Nonparametric estimation of the discontinuous variance function using adjusted residuals (잔차 수정을 이용한 불연속 분산함수의 비모수적 추정)

  • Huh, Jib
    • Journal of the Korean Data and Information Science Society
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    • v.27 no.1
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    • pp.111-120
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    • 2016
  • In usual, the discontinuous variance function was estimated nonparametrically using a kernel type estimator with data sets split by an estimated location of the change point. Kang et al. (2000) proposed the Gasser-$M{\ddot{u}}ller$ type kernel estimator of the discontinuous regression function using the adjusted observations of response variable by the estimated jump size of the change point in $M{\ddot{u}}ller$ (1992). The adjusted observations might be a random sample coming from a continuous regression function. In this paper, we estimate the variance function using the Nadaraya-Watson kernel type estimator using the adjusted squared residuals by the estimated location of the change point in the discontinuous variance function like Kang et al. (2000) did. The rate of convergence of integrated squared error of the proposed variance estimator is derived and numerical work demonstrates the improved performance of the method over the exist one with simulated examples.

Development of implant loading device for animal study about various loading protocol: a pilot study

  • Yoon, Joon-Ho;Park, Young-Bum;Cho, Yuna;Kim, Chang-Sung;Choi, Seong-Ho;Moon, Hong-Seok;Lee, Keun-Woo;Shim, June-Sung
    • The Journal of Advanced Prosthodontics
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    • v.4 no.4
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    • pp.227-234
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    • 2012
  • PURPOSE. The aims of this pilot study were to introduce implant loading devices designed for animal study and to evaluate the validity of the load transmission ability of the loading devices. MATERIALS AND METHODS. Implant loading devices were specially designed and fabricated with two implant abutments and cast metal bars, and orthodontic expansion screw. In six Beagles, all premolars were extracted and two implants were placed in each side of the mandibles. The loading device was inserted two weeks after the implant placement. According to the loading protocol, the load was applied to the implants with different time and method, simulating early, progressive, and delayed loading. The implants were clinically evaluated and the loading devices were removed and replaced to the master cast, followed by stress-strain analysis. Descriptive statistics of remained strain (${\mu}{\varepsilon}$) was evaluated after repeating three cycles of the loading device activation. Statistic analysis was performed using nonparametric, independent t-test with 5% significance level and Friedman's test was also used for verification. RESULTS. The loading devices were in good action. However, four implants in three Beagles showed loss of osseointegration. In stress-strain analysis, loading devices showed similar amount of increase in the remained strain after applying 1-unit load for three times. CONCLUSION. Specialized design of the implant loading device was introduced. The loading device applied similar amount of loads near the implant after each 1-unit loading. However, the direction of the loads was not parallel to the long axis of the implants as predicted before the study.

On asymptotics for a bias-corrected version of the NPMLE of the probability of discovering a new species (신종발견확률의 편의보정 비모수 최우추정량에 관한 연구)

  • 이주호
    • The Korean Journal of Applied Statistics
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    • v.6 no.2
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    • pp.341-353
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    • 1993
  • As an estimator of the conditional probability of discovering a new species at the next observation after a sample of certain size is taken, the one proposed by Good(1953) has been most widely used. Recently, Clayton and Frees(1987) showed via simulation that their nonparametric maximum likelihood estimator(NPMLE) has smaller MSE than Good's estimator when the population is relatively nonuniform. Lee(1989) proved that their conjecture is asymptotically true for truncated geometric population distributions. One shortcoming of the NPMLE, however, is that it has a considerable amount of negative bias. In this study we proposed a bias-corrected version of the NPMLE for virtually all realistic population distributions. We also showed that it has a smaller asymptotic MSE than Good's extimator except when the population is very uniform. A Monte Carlo simulation was performed for small sample sizes, and the result supports the asymptotic results.

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Clinical Experiences with Foreign Body Granuloma of the Nose: 7-Year Experience with 18 Patients (비부 이물 육아종의 임상적 경험)

  • Park, Tae-Hwan;Seo, Sang-Won;Kim, June-Kyu;Chang, Choong-Hyun
    • Archives of Plastic Surgery
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    • v.38 no.4
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    • pp.391-397
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    • 2011
  • Purpose: The injection of various materials, including medical fillers and unregulated products, is widespread, potentially causing the development of foreign body granulomas. Should this occur on the nose, the contour deformity and inflammatory signs that result from these granulomas are aesthetically undesirable to patients. The purpose of our study is to share our experiences using different surgical approaches, depending on the affected portion of the nose, to optimize management of this challenging problem and to evaluate patient's satisfaction using our in-house questionnaire along with degree of improvement by two independent plastic surgeons. Methods: We treated 18 patients who underwent surgical excision of nasal foreign body granulomas via a perilesional approach to the lesion (n=12) or by transcolumellar incision (n=6) at our hospital over a period of seven years from March 2003 to October 2010. Nonparametric statistics were used and are presented as medians (25th-75th). Patient satisfaction was evaluated on a scale of 1 to 5 using an in-house questionnaire. All pre-and post-operative photographs were analyzed by two independent plastic surgeons. Post-operative outcomes were evaluated based on the surgeons' consensus ratings. Results: All patients receiving the transcolumellar approach reported a high level of satisfaction with the results. All but two patients who received the perilesional approach were satisfied with the outcome. No outcomes were rated as no change or worse by the consensus ratings. Conclusion: For the upper two-thirds of the nose, perilesional surgical excision can lead to substantial patient satisfaction with modified contour deformity and infection control. The transcolumellar approach resulted in better outcomes and patient satisfaction for the lower one-third of the nose.

The Effect of social Support on Chronic Stress and Immune System in Male Manufacturing Workers (사회적 지지가 만성적 스트레스와 면역체계에 미치는 영향)

  • Koh, Sang-Baek;Park, Jong-Ku;Cha, Bong-Suk;Chang, Sei-Jin
    • Journal of Preventive Medicine and Public Health
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    • v.35 no.4
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    • pp.287-294
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    • 2002
  • Objectives : To examine whether cumulative chronic stress influences the immune status, and to verify the effect of social support on the relationship between these two dimensions in male manufacturing workers. Methods : A total of 39 workers were recruited for this study. A structured-questionnaire was used to assess general characteristics, job characteristics (work demand and decision latitude), psychosocial distress, and social support. The serum levels of CD4 and CD8 were measured as immune markers, and were collected between 8:00 and 10:00am in order to standardize the markers. Nonparametric statistics were used to estimate the differences between job characteristics and the immune markers. Results : General characteristics, and health-related behaviors, were not associated with CD4, CD8 or CD4/CD8. No relationships were found between job characteristics and the mean levels of immune reactivity. These results were consistent, even after controlling for social support. Social support failed to modify the relationship toward work demand, decision latitude or psychosocial distress to CD4, CD8, and CD4/CD8. Conclusion : Cumulative chronic life stress might not influence the immune status, and the effects of social support on the immune function under chronic stress, may not play a crucial role in modifying the relationships. This implication supports that the effect of stress on the immune function may be determined by the characteristics of that stress. further research should effectively considers the type, magnitude and timing of a stress event, and modifiable factors, such as personality traits, coping style, and hormone excretion levels, on the alteration of immune status.

Effect of Web-Based Video Self-Management Education Program for Infection Prevention in Patients with Cancer Receiving Chemotherapy: A Preliminary Study (항암화학요법을 받는 환자를 위한 웹기반 동영상 감염예방 자가관리 교육프로그램 효과: 예비연구)

  • Ha, Boo-Young;Lee, Insook;Jeong, Seon-Gyeong;Jang, Chun-sun
    • Journal of Korean Academic Society of Home Health Care Nursing
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    • v.27 no.3
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    • pp.294-305
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    • 2020
  • Purpose: The aim of this study was to examine the preliminary effects of applying a developed web-based video education program in patients with cancer receiving chemotherapy. Methods: A one-group pre-post test design was used. The web-based video education program to prevent infection consisted of 5 subjects. The program was confirmed to be valid by an expert group of doctors and nurses. Convenience sampling of 23 subjects was performed to evaluate the effectiveness of the web-based video education program. Data were analyzed based on nonparametric statistics using SPSS 25.0 software. Results: Per the results of the study, knowledge and self-management behavior of infection prevention significantly improved after application of the program; however, there was no significant difference in self-efficacy. Conclusion: It was confirmed that the web-based video education program is effective to improve the knowledge and self-management behavior of infection prevention. However, as a preliminary study, this study did not have external validity. Therefore, it is necessary to verify the effectiveness of the program through randomized controlled trials and confirm the true infection prevention effect that was not considered in this research design.

Effects of therapeutic horse-riding program on the walking ability of students with intellectual disabilities

  • Kang, Ok-Deuk
    • Journal of Animal Science and Technology
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    • v.63 no.2
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    • pp.440-452
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    • 2021
  • The purpose of this study was to determine if an 8-week therapeutic riding (TR) program was effective in improving the walking ability of students with intellectual disabilities. Thirteen students diagnosed with intellectual disabilities participated in the TR program. TR sessions were conducted twice a week (30 min per session), with a total of 16 rides taking place over an 8-week period. A gait measurement analyzer was used to measure progress based on a turn test (6-m walking and turning test), walk test (10-m walking), and timed up and go (TUG) test. Measurements were made three times: before horse-riding (P0), after 4 weeks (8 rides) of horse-riding (P1), and after 8 weeks (16 rides) of horse-riding (P2). Data analysis was conducted using SPSS software (ver. 22.0). Descriptive statistics were generated on the general characteristics of the subjects, and the Kolmogorov-Smirnov test was used to verify the normality of the data. Because of the lack of normality, the data were analyzed using a nonparametric method and the significance level was set to 0.05. Measurements of the duration of the forward gait cycle (s) in the turn test and the forward gait speed (m/s) in the walk test indicated improved walking ability after the TR program (p < 0.001); the stride length (% height) also increased significantly (p < 0.05). The walk test revealed a significant effect of the program on the duration of the forward gait cycle (p < 0.05), while there were significant improvements on the left and right of the elaborated strides (p < 0.001). No significant improvement in TUG test performance was observed after the TR program. In this study, an 8-week TR program had positive results on gait. Therefore, further research is merited, where TR programs are likely to improve the walking ability of individuals with intellectual disabilities.

Effect of nicotine on orthodontic tooth movement and bone remodeling in rats

  • Lee, Sung-Hee;Cha, Jung-Yul;Choi, Sung-Hwan;Kim, Baek-il;Cha, Jae-Kook;Hwang, Chung-Ju
    • The korean journal of orthodontics
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    • v.51 no.4
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    • pp.282-292
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    • 2021
  • Objective: To quantitatively analyze the effect of nicotine on orthodontic tooth movement (OTM) and bone remodeling in rats using micro-computed tomography and tartrate-resistant acid phosphatase immunostaining. Methods: Thirty-nine adult male Sprague-Dawley rats were randomized into three groups: group A, 0.5 mL normal saline (n = 9, 3 per 3, 7, and 14 days); group B, 0.83 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days); and group C, 1.67 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days). Each animal received daily intraperitoneal injections of nicotine/saline from the day of insertion of identical 30-g orthodontic force delivery systems. A 5-mm nickel-titanium closed-coil spring was applied between the left maxillary first molar (M1) and the two splinted incisors. The rate of OTM and volumetric bone changes were measured using micro-computed tomography. Osteoclasts were counted on the mesial alveolar bone surface of the distobuccal root of M1. Six dependent outcome variables, including the intermolar distance, bone volume fraction, bone mineral density, trabecular thickness, trabecular volume, and osteoclast number, were summarized using simple descriptive statistics. Nonparametric Kruskal-Wallis tests were used to evaluate differences among groups at 3, 7, and 14 days of OTM. Results: All six dependent outcome variables showed no statistically significant among group-differences at 3, 7, and 14 days. Conclusions: The findings of this study suggest that nicotine does not affect OTM and bone remodeling, although fluctuations during the different stages of OTM in the nicotine groups should be elucidated in further prospective studies.

A Study on the Safety and Health Management Plan of Subway Construction Workers using Macpa Stress Index (맥파 스트레스 지수를 활용한 도시철도 건설공사자의 안전보건관리 방안에 관한 연구)

  • Joung Sik, Chae;Yu Jeong, Lee;Jong bin, Lee;Seong Rok, Chang
    • Journal of the Korean Society of Safety
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    • v.37 no.6
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    • pp.102-107
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    • 2022
  • South Korea will soon be a super-aged society, as more than 20.6% of its population will be 65 years and older by 2025. As of 2022, 17.5% of the total population in South Korea is 65 years and older, which exceeds the set threshold for an aged society, where more than 14% of the population is 65 years and older. The proportion of older subway construction workers has increased. Aging workers and their work stress negatively impact their workability. A previous study demonstrated that the stress index measured using the uBioMacpa measurement device (Macpa stress index) had a significant correlation with work stress in South Korea. The device tests vascular health and measures stress levels via Macpa signal analysis. In this study, the pulse waves of subway construction workers were measured using uBioMacpa to identify their stress levels. The stress levels were analyzed by age, years of service, job position, employment type, and work type. Herein, these statistics could not be easily represented by a normal distribution; therefore, the Kruskal-Wallis test, a nonparametric statistical method, was used for the analysis of data. The results showed that age, job position, employment type, and working type affected the Macpa stress index and the stress levels of workers increased with age. In terms of job position, technical engineers were more stressed than other workers because of their poor working environment. In terms of employment type, daily-wage workers were more stressed than other workers. In terms of working type, tunneling, waterproofing, and construction scored the highest Macpa stress indexes without any significant difference, whereas earthworks scored the lowest. Based on the analysis of Macpa stress index, safety and health management plans were proposed to reduce the stress levels of workers. Moreover, a manual for efficient stress management must be developed for subway construction workers.

Analysis of Factor Affecting for Improving Construction Engineering Market

  • Park, Junho;Yu, Jungho
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.450-453
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    • 2015
  • The Construction Engineering Industry (CEI) is construction field based on professional knowledge, staff and information service, and is distinguished by construction activity. The contemporary CEI market has extended globally and diversified construction work classifications. International construction engineering companies now have an important economic and social effect. Over the last five years (2009 to 2013), the top-200 global engineering firms reported global revenue that grew from 54.4 billion to 71.5 billion, about 27% growth (ENR, 2014). Countries such as the U.S.A., Canada, those in Europe (Several developed countries, i.e., United Kingdom, Netherlands, France, Spain, France, Italy, and Spain), Australia, Japan, China, and Korea comprise the bulk of world construction engineering revenue. Although the construction engineering market continues to grow, much of the work is limited to Europe, mid-Asia, and Asia. Additionally, specific construction types are focused on building projects, industrial plants, and refining plants. As such, there are imbalances in the construction engineering market and some market saturation. Further, there is heavy competition and the construction engineering market may shrink in the future. This paper analyzed various factors affecting the construction engineering market, specifically looking at construction classifications and factors related to a global market. To accomplish this, we collected to data from Engineering News Record (ENR) and recast each variable. And we used nonparametric statistics because the number of cases were small, making it difficult to assume a case's population parameter. Then we tested with the Kruskal-Wallis test and drew results. The results indicate that concentration in particular construction types and extending global regional markets will be have a positive effect on the overall global construction engineering market..

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