• Title/Summary/Keyword: response variability

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Statistical notes for clinical researchers: simple linear regression 3 - residual analysis

  • Kim, Hae-Young
    • Restorative Dentistry and Endodontics
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    • v.44 no.1
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    • pp.11.1-11.8
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    • 2019
  • In the previous sections, simple linear regression (SLR) 1 and 2, we developed a SLR model and evaluated its predictability. To obtain the best fitted line the intercept and slope were calculated by using the least square method. Predictability of the model was assessed by the proportion of the explained variability among the total variation of the response variable. In this session, we will discuss four basic assumptions of regression models for justification of the estimated regression model and residual analysis to check them.

Isolate Virulence and Cultivar Response in the Winter Wheat: Pyrenophora tritici-repentis (Tan Spot) Pathosystem in Oklahoma

  • Kader, Kazi A.;Hunger, Robert M.;Payton, Mark E.
    • The Plant Pathology Journal
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    • v.37 no.4
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    • pp.339-346
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    • 2021
  • Prevalence of tan spot of wheat caused by the fungus Pyrenophora tritici-repentis has become more prevalent in Oklahoma as no-till cultivation in wheat has increased. Hence, developing wheat varieties resistant to tan spot has been emphasized, and selecting pathogen isolates to screen for resistance to this disease is critical. Twelve isolates of P. tritici-repentis were used to inoculate 11 wheat cultivars in a greenhouse study in splitplot experiments. Virulence of isolates and cultivar resistance were measured in percent leaf area infection for all possible isolate x cultivar interactions. Isolates differed significantly (P < 0.01) in virulence on wheat cultivars, and cultivars differed significantly in disease reaction to isolates. Increased virulence of isolates detected increased variability in cultivar response (percent leaf area infection) (r = 0.56, P < 0.05) while increased susceptibility in cultivars detected increased variance in virulence of the isolates (r = 0.76, P < 0.01). A significant isolate × cultivar interaction indicated specificity between isolates and cultivars, however, cluster analysis indicated low to moderate physiological specialization. Similarity in wheat cultivars in response to pathogen isolates also was determined by cluster analysis. The use of diverse isolates of the fungus would facilitate evaluation of resistance in wheat cultivars to tan spot.

The effect of foundation soil behavior on seismic response of long bridges

  • Hoseini, Shima Sadat;Ghanbari, Ali;Davoodi, Mohammad;Kamal, Milad
    • Geomechanics and Engineering
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    • v.17 no.6
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    • pp.583-595
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    • 2019
  • In this paper, a comprehensive investigation of the dynamic response of a long-bridge subjected to spatially varying earthquake ground motions (SVEGM) is performed based on a proposed analytical model which includes the effect of soil-structure interaction (SSI). The spatial variability of ground motions is simulated by the powerful record generator, SIMQKE II. Modeling of the SSI in the system is simplified by replacing the pile foundations and soil with sets of independent equivalent linear springs and dashpots along the pile groups. One of the most fundamental objectives of this study is to examine how well the proposed model simulates the dynamic response of a bridge system. For this purpose, the baseline data required for the evaluation process is derived from analyzing a 3D numerical model of the bridge system which is validated in this paper. To emphasize the importance of the SVEGM and SSI, bridge responses are also determined for the uniform ground motion and fixed base cases. This study proposing a compatible analytical model concerns the relative importance of the SSI and SVEGM and shows that these effects cannot be neglected in the seismic analysis of long-bridges.

Seismic Response Evaluation of PSCI Girder Bridges Considering Stiffness Variation in Elastic Bearings (탄성받침의 강성 변동을 고려한 PSCI 거더 교량의 지진 응답 평가)

  • Yoon, Hyejin;Cho, Chang-Beck;Kim, Young-Jin;Kang, Jun Won
    • Journal of the Earthquake Engineering Society of Korea
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    • v.27 no.4
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    • pp.187-192
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    • 2023
  • An elastic bearing must be strong against vertical loads and flexible against horizontal loads. However, due to the material characteristics of rubber, it may show variability due to the manufacturing process and environmental factors. If the value applied in the bridge design stage and the actual measured value have different values or if the performance during operation changes, the performance required in the design stage may not be achieved. In this paper, the seismic response of bridges was compared and analyzed by assuming a case where quality deviation occurs during construction compared to the design value for elastic bearings, which have not only always served as traditional bearings but also have had many applications in recent seismic reinforcement. The bearing's vertical stiffness and shear stiffness deviation were considered separately for the quality deviation. In order to investigate the seismic response, a time history analysis was performed using artificial seismic waves. The results confirmed that the change in the bearing's shear stiffness affects the natural period and response of the structure.

ABCB1 Polymorphisms and Imatinib Response in Chronic Myeloid Leukemia Patients: A Systematic Review and Meta-analysis (ABCB1 유전적 다형성이 만성 골수성 백혈병 환자의 Imatinib 치료 반응에 미치는 영향: 체계적 문헌고찰 및 메타분석)

  • Ha, Hye Min;Chun, Pusoon
    • YAKHAK HOEJI
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    • v.60 no.3
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    • pp.118-127
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    • 2016
  • A growing number of studies have demonstrated that ABCB1 gene polymorphisms are associated with the variability of responses to imatinib. However, the effects of ABCB1 polymorphisms on imatinib response in chronic myeloid leukemia (CML) are inconsistent. The aim of the present study was to clarify the associations between ABCB1 polymorphisms and imatinib response in CML. A systematic literature review was performed. The databases of PubMed, Embase, and Cochrane Library were searched for all published studies from inception to December 2015. The following terms were used with functions of 'AND' and 'OR': 'chronic myeloid leukemia', 'CML', 'ABCB1', 'MDR1', 'polymorphism', 'SNP', and 'imatinib'. Using the Review Manager 5, odds ratios (ORs) were pooled to estimate the effect of ABCB1 polymorphisms on imatinib response in CML. The pooled analysis showed that ABCB1 2677 G allele was significantly associated with poor response to imatinib in African and Asian patients (GG vs TT, OR: 0.32, p<0.0001; GG+GT vs TT, OR: 0.44, p=0.0005). In subgroup analyses, African patients carrying ABCB1 1236 C allele exhibited higher risk for worse response, whereas Asian patients with 1236 C allele showed better response (CC+CT vs TT, OR: 0.41, p=0.008 for African; OR: 1.65, p=0.03 for Asian). There was no association between C3435T polymorphisms and imatinib response in African, Asian, and Caucasian CML patients.

Robust passive damper design for building structures under uncertain structural parameter environments

  • Fujita, Kohei;Takewaki, Izuru
    • Earthquakes and Structures
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    • v.3 no.6
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    • pp.805-820
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    • 2012
  • An enhanced and efficient methodology is proposed for evaluating the robustness of an uncertain structure with passive dampers. Although the structural performance for seismic loads is an important design criterion in earthquake-prone countries, the structural parameters such as storey stiffnesses and damping coefficients of passive dampers are uncertain due to various factors or sources, e.g. initial manufacturing errors, material deterioration, temperature dependence. The concept of robust building design under such uncertain structural-parameter environment may be one of the most challenging issues to be tackled recently. By applying the proposed method of interval analysis and robustness evaluation for predicting the response variability accurately, the robustness of a passively controlled structure can be evaluated efficiently in terms of the so-called robustness function. An application is presented of the robustness function to the design and evaluation of passive damper systems.

Control Variates for Percentile Estimation of Project Completion Time in PERT Network (통제변수를 이용한 PERT 네트워크에서 프로젝트 완료확률의 추정)

  • 권치명
    • Journal of the Korea Society for Simulation
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    • v.9 no.4
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    • pp.67-75
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    • 2000
  • Often system analysts are interested in the estimation of percentile for system performance. For instance, in PERT network system, the percentile that the project. Typically the control variate method is used to reduce the variability of mean response using the correlation between the response and the control variates with a little additional cost during the course of simulation. In the same spirit, we apply this method to estimate the percentile of project completion time in PERT system, and evaluate the efficiency of the controlled estimator for its percentile.1 Simulation results indicate that the controlled estimators are more effective in reducing the variances of estimators than the simple estimators, however those tend to a little underestimate the percentiles for some critical values. We need more simulation experiments to examine such a kind of bias problem. We expect this research presents a step forward in the area of variance reduction techniques of stochastic simulation.

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An Interactive Method for Multicriteria Simulation Optimization with Integer Variables (이산형 다기준 시뮬레이션 최적화를 위한 대화형 방법)

  • Shin, Wan-S.;Kim, Jae-Yong
    • Journal of Korean Institute of Industrial Engineers
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    • v.22 no.4
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    • pp.633-649
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    • 1996
  • An interactive multicriteria method, which is called the Modified Pairwise Comparison Stochastic Cutting Plane (MPCSCP) method, is proposed for determining the best levels of the integer decision variables needed to optimize a stochastic computer simulation with multiple response functions. MPCSCP combines good features from interactive tradeoff cutting plane methods and response surface methodologies. The proposed method uses a simple pairwise man-machine interaction and searches an integer space uniformly by using the experimental design which evaluates the decision space centering around an integer center point. The characteristics of the proposed method are investigated through an extensive computational study. The parameter configurations examined in the study are (1) variability of the sampling errors, (2) the size of experimental design, (3) the relaxation of cutting planes, and (4) the levels of decision maker's inconsistency.

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Endoscopic activity in inflammatory bowel disease: clinical significance and application in practice

  • Kyeong Ok Kim
    • Clinical Endoscopy
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    • v.55 no.4
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    • pp.480-488
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    • 2022
  • Endoscopy is vital for diagnosis, assessing treatment response, monitoring and surveillance in patients with inflammatory bowel disease (IBD). With the growing importance of mucosal healing as a treatment target, the assessment of disease activity by endoscopy has been accepted as the standard of care for IBD. There are many endoscopic activity indices for facilitating standardized reporting of the gastrointestinal mucosal appearance in IBD, and each index has its strengths and weaknesses. Although most endoscopic indices do not have a clear-cut validated definition, endoscopic remission or mucosal healing is associated with favorable outcomes, such as a decreased risk of relapse. Therefore, experts suggest utilizing endoscopic indices for monitoring disease activity and optimizing treatment to achieve remission. However, the regular monitoring of endoscopic activity is limited in practice owing to several factors, such as the complexity of the procedure, time consumption, inter-observer variability, and lack of a clear-cut, validated definition of endoscopic response or remission. Although experts have recently suggested consensus-based definitions, further studies are needed to define the values that can predict long-term outcomes.

Comparative antigen analysis of yrichomonus vaginulis by enzyme-linked immunoelectrotransfer blot technique (효소면역 전기영동 이적법을 이용한 질트리코모나스 항원의 비교 분석)

  • 민득영;임미혜
    • Parasites, Hosts and Diseases
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    • v.30 no.4
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    • pp.323-328
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    • 1992
  • Analysis of siR isolates of Trichemenes veginalis was carried out with sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunoelectrotransfer blot (EITB). Trichloroacetic acid-treated antigens of the 6 isolates revealed 25 protein profiles ranging 12~170 kDa of molecular weight in SDS-PAGE. In EITB, the specific immunogenic bands were visualized at 51 kDa and 96 kDa when HY-1 antigen was probed with difFerent mice sera immunized with 6 isolates of T. vaginalis. The banding patterns with different sera showed isolate-to-isolate variability. In EITB, homologous antigen (HY-1) did not show any enhanced response in reacting to homologous antiserum(HY-1) when 6 isolates of T. vaginalis were probed with a single serum (HY-1). It is assumed that the different banding patterns of six isolates show isolate-to-isolate variability and immunogenic common bands in 41, 47, 74 and 9:k kDa on EITB may connote the important significance on immune response in T. vaginalis infection.

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