• Title/Summary/Keyword: Change-point analysis

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Validation of Critical Care Non-verbal Pain Scale for Critically Ill Patients (중환자 통증사정 도구의 타당성 평가)

  • Choi, Eun Hee;Kim, Jin Hee;Ko, Mi Suk;Kim, Ji Yang;Kwon, Eun Ok;Jang, In Sun
    • Journal of Korean Clinical Nursing Research
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    • v.19 no.2
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    • pp.245-254
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    • 2013
  • Purpose: This study was done to examine predictive validity of Critical Care Non-verbal Pain Scale (CNPS) and develop criteria for pain assessment using CNPS with critically ill patients who have communication problems. Methods: Data were collected from intensive care units at three major general hospitals in Seoul and Kyunggi province. During each observation, a nurse assessed pain severity using CNPS ratings (range 0-9) at four treatment stages: at rest, during central catheter dressing change (nonpainful procedure), position change and suctioning (routine painful procedures). Patients also assessed their pain using a self-report 4-point VRS-4. Results: There were significant differences between the four treatment stages except between "at rest" and "nonpainful procedure". Strong correlations were found between CNPS and VRS-4 for "at rest" (r=.552, p<.001), central catheter dressing change (r=.505, p<.001), position change (r=.709, p<.001), and suctioning (r=.662, p<.001). ROC curve analysis of CNPS based on 3 point on VRS-4 showed the cutoff point was 3 for CNPS, the starting point for pain management with 73% sensitivity, 92.2% specificity, 73% positive predictive value, and 92.8% negative predictive value. Conclusion: Results indicate that CNPS is a valid tool for measuring pain in critically ill patients with communication problems and 3 point should be the standardized pain treatment point.

An Adaptive Structural Model When There is a Major Level Change (수준에서의 변화에 적응하는 구조모형)

  • 전덕빈
    • Journal of the Korean Operations Research and Management Science Society
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    • v.12 no.1
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    • pp.19-26
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    • 1987
  • In analyzing time series, estimating the level or the current mean of the process plays an important role in understanding its structure and in being able to make forecasts. The studies the class of time series models where the level of the process is assumed to follow a random walk and the deviation from the level follow an ARMA process. The estimation and forecasting problem in a Bayesian framework and uses the Kalman filter to obtain forecasts based on estimates of level. In the analysis of time series, we usually make the assumption that the time series is generated by one model. However, in many situations the time series undergoes a structural change at one point in time. For example there may be a change in the distribution of random variables or in parameter values. Another example occurs when the level of the process changes abruptly at one period. In order to study such problems, the assumption that level follows a random walk process is relaxed to include a major level change at a particular point in time. The major level change is detected by examining the likelihood raio under a null hypothesis of no change and an alternative hypothesis of a major level change. The author proposes a method for estimation the size of the level change by adding one state variable to the state space model of the original Kalman filter. Detailed theoretical and numerical results are obtained for th first order autoregressive process wirth level changes.

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Analysis of Spatial Characteristics of Business-Type-Changed Parcel in Hongik-University Commercial Area, Seoul - Focused on the View Point of Commercial Gentrification - (서울시 홍대상권 내 업종변화 필지의 공간적 특성 분석 - 상업 젠트리피케이션의 관점에서 -)

  • Kim, Dongjun;Kim, Kijung;Lee, Seungil
    • Journal of Korea Planning Association
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    • v.54 no.2
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    • pp.5-16
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    • 2019
  • The purpose of this study is to analyze the spatial characteristics of business-type-changed parcel in the Hongik-University commercial area, from the view point of commercial gentrification. A commercial gentrification occurs through a business-type-change in a spatial basic unit (microscopic spatial unit such as parcel) of an area which has not been considered in relavent policies and research. So, this study analyzed the spatial characteristics of business-type-changed parcels using the Cox's proportional hazard regression model. The main results of this study are as follows. First, as new developments in the adjacent area occur, the business-type-change probability increases. Second, by the commercial area division, the business-type-change probability is different. Finally, the accessibility is better, the probability is higher. These results could suggest that a consideration of the spatial characteristics form microscopic viewpoint is necessary to understand the commercial gentrification. And these could be used as basic data for a gentrification diagnostic and management system, which can predict gentrification from the view point of business-type-change on the basis of a parcel.

Generalization of Point Feature in Digital Map through Point Pattern Analysis (점패턴분석을 이용한 수치지형도의 점사상 일반화)

  • 유근배
    • Spatial Information Research
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    • v.6 no.1
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    • pp.11-23
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    • 1998
  • Map generalization functions to visualize the spatial data or to change their scale by changing the level of details of data. Until recently, the studies on map generalization have concentrated more on line features than on point features. However, point features are one of the essential components of digital maps and cannnot be ignored because of the great amount of information they carry. This study, therefore, aimed to find out a detailed procedure of point features' generalization. Particularly, this work chose the distribution pattern of point features as the most important factor in the point generalization in investigating the geometric characteristics of source data. First, it attempted to find out the characteristics of distribution pattern of point features through quadrat analysis with Grieg-Smith method and nearest-neighbour analysis. It then generalized point features through the generalization threshold which did not alter the characteristics of distribution pattern and the removal of redudant point feautres. Therefore, the generalization procedure of point features provided by this work maintained the geometric characteristics as much as possible.

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A Family of Tests for Trend Change in Mean Residual Life with Known Change Point

  • Na, Myung-Hwan;Kim, Jae-Joo
    • Communications for Statistical Applications and Methods
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    • v.7 no.3
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    • pp.789-798
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    • 2000
  • The mean residual function is the expected remaining life of an item at age x. The problem of trend change in the mean residual life is great interest in the reliability and survival analysis. In this paper, we develop a family of test statistics for testing whether or not the mean residual life changes its trend. The asymptotic normality of the test statistics is established. Monte Carlo simulations are conducted to study the performance of our test statistics.

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The Change Point Analysis in Time Series Models

  • Lee, Sang-Yeol
    • Proceedings of the Korean Statistical Society Conference
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    • 2005.11a
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    • pp.43-48
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    • 2005
  • We consider the problem of testing for parameter changes in time series models based on a cusum test. Although the test procedure is well-established for the mean and variance in time series models, a general parameter case has not been discussed in the literature. Therefore, here we develop a cusum test for parameter change in a more general framework. As an example, we consider the change of the parameters in an RCA(1) model and that of the autocovariances of a linear process. We also consider the variance change test for unstable models with unit roots and GARCH models.

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A trend analysis of seasonal average temperatures over 40 years in South Korea using Mann-Kendall test and sen's slope (Mann-Kendall 비모수 검정과 Sen's slope를 이용한 최근 40년 남한지역 계절별 평균기온의 경향성 분석)

  • Jin, Dae-Hyun;Jang, Sung-Hwan;Kim, Hee-Kyung;Lee, Yung-Seop
    • The Korean Journal of Applied Statistics
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    • v.34 no.3
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    • pp.439-447
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    • 2021
  • Due to the frequent emergence of global abnormal climates, related studies on meteorological change is being actively proceed. However, the research on trend analysis using weather data accumulated over a long period of time was insufficient. In this study, the trend of temperature time series data accumulated from automated surface observing system (ASOS) for 40 years was analyzed by using a non-parametric analysis method. As a result of the Mann-Kendall test on the annual average temperature and seasonal average temperature time series data in South Korea, it has shown that an upward trend exists. In addition, the result of calculating the Sen's slope, which can determine the degree of tendency before and after the searched change point by applying the Pettitt test, recent data after the fluctuation point confirmed that the tendency of temperature rise was even greater.

Correlation Analysis of Edema Sensation in Postpartum Mothers, Inbody Edema Index, and Weight Change before and after Childbirth (산욕기 산모의 부종감각과 Inbody 부종지수, 출산 전후 체중변화의 상관성 분석)

  • Kim, Young-Eun;Kim, An-Na;Seo, Su-Min;Kim, Pyung-Wha;Son, Mi-Ju;Lee, Eun-Hee;Jang, Hyun-Chul
    • The Journal of Korean Obstetrics and Gynecology
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    • v.35 no.1
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    • pp.1-11
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    • 2022
  • Objectives: Management of the postpartum period is important for the health of mothers, and postpartum edema is one of the management targets. In this study, the relationship between the value measured by the device and the postpartum edema sensation was examined to explain the subjective sensation of the mother as an objective value. Methods: Data from 54 cases provided by 24 mothers within 6 weeks postpartum were used in the study. The degree of postpartum edema sensation was measured using a visual analog scale (VAS), and the effect of VAS changes on the body edema index and weight change before and after childbirth was estimated through linear regression analysis. Results: As a result of the regression analysis, when the edema sensation of the mothers VAS increased by 1 point, the Inbody edema index increased by 0.002 points (p=0.000, R2=0.272), and when the VAS increased by 1 point, the weight gain increased by 0.99 kg compared to before pregnancy (p=0.000, R2=0.243), and when VAS increased by 1 point, weight loss decreased by 0.56 kg compared to just before childbirth (p=0.004, R2=0.136). Conclusions: The results of this study, in which the edema sensation of postpartum mothers was statistically significantly related to the edema index and weight change before and after childbirth, showed that the edema sensation complained by the mother could be used as an evaluation index for postpartum edema management in the future.

Analysis for Force Distribution on Surface Between Busbar Contacts (부스바 접점 가동시 접촉면에서 압점력 해석)

  • Oh, Y.H.;Song, K.D.;Kim, K.S.;Kim, J.K.
    • Proceedings of the KIEE Conference
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    • 2003.04a
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    • pp.82-84
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    • 2003
  • In case contact between point of contacts is not achieved well, contact resistance is grown, and by current concentration at current conducting contacts can weld. In order to decrease contact resistance between contacts in case of busbar, installing spring between fixed contact and moving contact. and then force on faying surface of contacts increase and contact resistance decrease. But, in case increase force of spring to widen contact area, operating force moving contact can grow, on the contrary force of spring is small, contact resistance becomes low. Therefore, need to optimize force and number of spring. position, and also need to examine force change on contact surface at point of contact moving. In this paper, dynamic kinetics analysis for force on faying surface of contacts is performed at unsteady state. It is showed to not uniform force on surface between contacts, and we can got more uniform force by means of change spring position.

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