Journal articles: 'Kappa coefficient'

1

Lin, Yuan Horng. "Fuzzy Kappa Coefficient with Simulated Comparisons." Applied Mechanics and Materials 303-306 (February 2013): 372–75. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.372.

Full text

Abstract:

The purpose of this study is to provide a new Kappa coefficient based on fuzzy scoring. This new Kappa is called fuzzy Kappa. Fuzzy theory has been widely used in quantitative research and many researches indicate its positive utility. Moreover, viewpoints of measurement according to fuzzy theory conform to the thinking of human thoughts. Therefore, it is feasible to measure the scoring of decision-making or judgment. In addition, Kappa coefficient is one kind of rater reliability and it is to measure the consistency on judgment among raters. Traditional Kappa coefficient is based on the crisp measurement and it violates the psychological nature of human decision-making. Therefore, in this study, fuzzy Kappa, which is based on the fuzzy measurement, is provided. Besides, data simulation is designed to compare of these two Kappa coefficients. The results show that fuzzy Kappa performs better than traditional Kappa. Based on the findings of this study, some suggestions and recommendations are discussed for future research.

APA, Harvard, Vancouver, ISO, and other styles

2

Thompson, W. Douglas, and Stephen D. Walter. "A rEAPPRAISAL OF THE KAPPA COEFFICIENT." Journal of Clinical Epidemiology 41, no. 10 (January 1988): 949–58. http://dx.doi.org/10.1016/0895-4356(88)90031-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Warrens, Matthijs J. "New Interpretations of Cohen’s Kappa." Journal of Mathematics 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/203907.

Full text

Abstract:

Cohen’s kappa is a widely used association coefficient for summarizing interrater agreement on a nominal scale. Kappa reduces the ratings of the two observers to a single number. With three or more categories it is more informative to summarize the ratings by category coefficients that describe the information for each category separately. Examples of category coefficients are the sensitivity or specificity of a category or the Bloch-Kraemer weighted kappa. However, in many research studies one is often only interested in a single overall number that roughly summarizes the agreement. It is shown that both the overall observed agreement and Cohen’s kappa are weighted averages of various category coefficients and thus can be used to summarize these category coefficients.

APA, Harvard, Vancouver, ISO, and other styles

4

De Raadt, Alexandra, Matthijs J. Warrens, Roel J. Bosker, and Henk A. L. Kiers. "Kappa Coefficients for Missing Data." Educational and Psychological Measurement 79, no. 3 (January 16, 2019): 558–76. http://dx.doi.org/10.1177/0013164418823249.

Full text

Abstract:

Cohen’s kappa coefficient is commonly used for assessing agreement between classifications of two raters on a nominal scale. Three variants of Cohen’s kappa that can handle missing data are presented. Data are considered missing if one or both ratings of a unit are missing. We study how well the variants estimate the kappa value for complete data under two missing data mechanisms—namely, missingness completely at random and a form of missingness not at random. The kappa coefficient considered in Gwet ( Handbook of Inter-rater Reliability, 4th ed.) and the kappa coefficient based on listwise deletion of units with missing ratings were found to have virtually no bias and mean squared error if missingness is completely at random, and small bias and mean squared error if missingness is not at random. Furthermore, the kappa coefficient that treats missing ratings as a regular category appears to be rather heavily biased and has a substantial mean squared error in many of the simulations. Because it performs well and is easy to compute, we recommend to use the kappa coefficient that is based on listwise deletion of missing ratings if it can be assumed that missingness is completely at random or not at random.

APA, Harvard, Vancouver, ISO, and other styles

5

Kvålseth, Tarald O. "Measurement of Interobserver Disagreement: Correction of Cohen’s Kappa for Negative Values." Journal of Probability and Statistics 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/751803.

Full text

Abstract:

As measures of interobserver agreement for both nominal and ordinal categories, Cohen’s kappa coefficients appear to be the most widely used with simple and meaningful interpretations. However, for negative coefficient values when (the probability of) observed disagreement exceeds chance-expected disagreement, no fixed lower bounds exist for the kappa coefficients and their interpretations are no longer meaningful and may be entirely misleading. In this paper, alternative measures of disagreement (or negative agreement) are proposed as simple corrections or modifications of Cohen’s kappa coefficients. The new coefficients have a fixed lower bound of −1 that can be attained irrespective of the marginal distributions. A coefficient is formulated for the case when the classification categories are nominal and a weighted coefficient is proposed for ordinal categories. Besides coefficients for the overall disagreement across categories, disagreement coefficients for individual categories are presented. Statistical inference procedures are developed and numerical examples are provided.

APA, Harvard, Vancouver, ISO, and other styles

6

Gjørup, Thomas. "The Kappa Coefficient and the Prevalence of a Diagnosis." Methods of Information in Medicine 27, no. 04 (October 1988): 184–86. http://dx.doi.org/10.1055/s-0038-1635539.

Full text

Abstract:

SummaryThe kappa coefficient is a widely used measure of agreement between observers’ independent recording of diagnoses. Kappa adjusts the overall agreement for expected chance agreement. The dependence of kappa on the prevalence . of a diagnosis has not previously been emphasized. This dependence means that kappa does not give a general statement of the reproducibility of a diagnosis. The result of a study of observer agreement should, therefore, not – as it has been done in several studies – be given by the kappa value alone. The kappa value should always be given together with the original results of the study.

APA, Harvard, Vancouver, ISO, and other styles

7

Nguyen, Loc. "A Fast Computational Formula for Kappa Coefficient." Science Journal of Clinical Medicine 4, no. 1 (2015): 1. http://dx.doi.org/10.11648/j.sjcm.20150401.11.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Vanbelle, Sophie. "Asymptotic variability of (multilevel) multirater kappa coefficients." Statistical Methods in Medical Research 28, no. 10-11 (August 22, 2018): 3012–26. http://dx.doi.org/10.1177/0962280218794733.

Full text

Abstract:

Agreement studies are of paramount importance in various scientific domains. When several observers classify objects on categorical scales, agreement can be quantified through multirater kappa coefficients. In most statistical packages, the standard error of these coefficients is only available under the null hypothesis that the coefficient is equal to zero, preventing the construction of confidence intervals in the general case. The aim of this paper is triple. First, simple analytic formulae for the standard error of multirater kappa coefficients will be given in the general case. Second, these formulae will be extended to the case of multilevel data structures. The formulae are based on simple matrix algebra and are implemented in the R package “multiagree”. Third, guidelines on the choice between the different mulitrater kappa coefficients will be provided.

APA, Harvard, Vancouver, ISO, and other styles

9

Lipsitz, Stuart R., Nan M. Laird, Troyen A. Brennan, and Michael Parzen. "Estimating the kappa-coefficient from a Selected Sample." Journal of the Royal Statistical Society: Series D (The Statistician) 50, no. 4 (December 2001): 407–16. http://dx.doi.org/10.1111/1467-9884.00286.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Luz, Laércio Lima, Lívia Maria Santiago, João Francisco Santos da Silva, and Inês Echenique Mattos. "Psychometric properties of the Brazilian version of the Vulnerable Elders Survey-13 (VES-13)." Cadernos de Saúde Pública 31, no. 3 (March 2015): 507–15. http://dx.doi.org/10.1590/0102-311x00011714.

Full text

Abstract:

This study aims to assess the psychometric properties of the Brazilian version of the Vulnerable Elders Survey-13 (VES-13). Interviews were carried out with individuals aged 60 years and over receiving care at an ambulatory cancer centre. Test-retest reliability was assessed using the Spearman correlation coefficient, intraclass correlation coefficients and Cohen's kappa coefficient. Construct validity was assessed by testing convergent and discriminant validity using principal component analysis and Varimax rotation. The Spearman correlation coefficient value of the comparison between test and retest scores was 0.98 (p < 0.001). All intraclass correlation coefficient values were higher than 0.60 and kappa coefficients varied between 0.33 and 0.94. Three identified factors explained 72.6% of overall sample variance. VES-13 presented good convergent validity and reasonable discriminant validity. The psychometric properties of the adapted version of the VES-13 are consistent and adequate for use with the Brazilian population.

APA, Harvard, Vancouver, ISO, and other styles

11

Jumniensuk, Chayanit, Alexander Nobori, Thomas Lee, T. Niroshi Senaratne, Dinesh Rao, and Sheeja Pullarkat. "Concordance of Peripheral Blood and Bone Marrow Next-Generation Sequencing in Hematologic Neoplasms." Advances in Hematology 2022 (March 26, 2022): 1–6. http://dx.doi.org/10.1155/2022/8091746.

Full text

Abstract:

Objective. Mutational analysis by next-generation sequencing (NGS) obtained by peripheral blood NGS has been of clinical interest to use as a minimally invasive screening tool. Our study evaluates the correlation between NGS results on peripheral blood and bone marrow in hematolymphoid disease. Method. We evaluated patients who had NGS for presumed hematologic malignancy performed on peripheral blood and bone marrow within a 1-year interval of each other. We excluded cases in which chemotherapy or bone marrow transplant occurred in the interval between the two tests. The concordance across peripheral blood and bone marrow NGS results was assessed by kappa coefficient analysis. Results. A total of 163 patients were studied. Concordance of peripheral blood and bone marrow NGS found in 150 patients (92.0%) with a kappa coefficient of 0.794 (kappa standard error 0.054) and P value for testing kappa <0.0001. Myeloid neoplasms showed concordant results in 77/78 cases (98.7%) with a kappa coefficient of 0.916. Lymphoid neoplasms showed concordant results in 26/31 cases (83.9%) with a kappa coefficient of 0.599. Nonneoplastic cases showed concordant results in 47/54 cases (87.0%) with a kappa coefficient of 0.743. Conclusion. Peripheral blood NGS is a reliable tool for mutational analysis and provides a less invasive method for screening and monitoring of the molecular profile.

APA, Harvard, Vancouver, ISO, and other styles

12

Srivastava, A., S. Bharadwaj, R. Dubey, V. B. Sharma, and S. Biswas. "MAPPING VEGETATION AND MEASURING THE PERFORMANCE OF MACHINE LEARNING ALGORITHM IN LULC CLASSIFICATION IN THE LARGE AREA USING SENTINEL-2 AND LANDSAT-8 DATASETS OF DEHRADUN AS A TEST CASE." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2022 (May 30, 2022): 529–35. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2022-529-2022.

Full text

Abstract:

Abstract. In recent years, the data science and remote sensing communities have started to align due to user-friendly programming tools, access to high-end consumer computing power, and the availability of free satellite data. In particular, publicly available data from the European Space Agency’s “Sentinel” and American Earth observation satellite” landsat” missions have been used in various remote sensing applications.Google Earth Engine (GEE) is such a tool that publicly allow the use of these available datasets, there is a large amount of available data in GEE, which are being used for computing and analysing purpose. In this article, we compare the classification performance of four supervised machine learning algorithms: Classification and Regression Tree (CART), Random forests (RF), Gradient tree boosting (GTB), Support vector machines (SVM). The study area is located at 30.3165° N, 78.0322° E near the Himalayan foothills, with four land-use land-cover (LULC) classes. The satellite imagery used for the classification were multi-temporal scenes from Sentinel-2 and LANDSAT-8 covering spring, summer, autumn, and winter conditions. Here we collected a total of 2084 sample points in which 536, 506, 505, 540 points belong to urban, water, forest and agriculture points respectively. which were divided into training (70%) and evaluation (30%) subsets. Accuracy was assessed through metrics derived from an error matrix, for accuracy measurement we use confusion and Cohen’s kappa calculation method.We have calculated CART (Accuracy 93.52% and Kappa coefficient 91.36%), Random Forest (Accuracy 95.86% and Kappa coefficient 94.48%),Gradient Tree Boost (Accuracy 95.33% and Kappa coefficient 93.37%),Support Vector Machine (Accuracy 73.54% and Kappa coefficient 76.28%) for Landsat 8 data sets and CART (Accuracy 89.24% and Kappa coefficient 85.64%), Random Forest (Accuracy 91.45% and Kappa coefficient 88.59%),Gradient Tree Boost (Accuracy 87.71% and Kappa coefficient 83.58%),Support Vector Machine (Accuracy 84.96% and Kappa coefficient 79.99%) for Sentinel2 data sets. Further analysis for accuracy and machine learning algorithm are discussed in result section.

APA, Harvard, Vancouver, ISO, and other styles

13

Artstein, Ron, and Massimo Poesio. "Inter-Coder Agreement for Computational Linguistics." Computational Linguistics 34, no. 4 (December 2008): 555–96. http://dx.doi.org/10.1162/coli.07-034-r2.

Full text

Abstract:

This article is a survey of methods for measuring agreement among corpus annotators. It exposes the mathematics and underlying assumptions of agreement coefficients, covering Krippendorff's alpha as well as Scott's pi and Cohen's kappa; discusses the use of coefficients in several annotation tasks; and argues that weighted, alpha-like coefficients, traditionally less used than kappa-like measures in computational linguistics, may be more appropriate for many corpus annotation tasks—but that their use makes the interpretation of the value of the coefficient even harder.

APA, Harvard, Vancouver, ISO, and other styles

14

Lee, James, and K. P. Fung. "Confidence interval of the kappa coefficient by bootstrap resampling." Psychiatry Research 49, no. 1 (October 1993): 97–98. http://dx.doi.org/10.1016/0165-1781(93)90033-d.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

von Eye, Alexander, and Maxine von Eye. "Can One Use Cohen’s Kappa to Examine Disagreement?" Methodology 1, no. 4 (January 2005): 129–42. http://dx.doi.org/10.1027/1614-2241.1.4.129.

Full text

Abstract:

Abstract. This research discusses the use of Cohen’s κ (kappa), Brennan and Prediger’s κn, and the coefficient of raw agreement for the examination of disagreement. Three scenarios are considered. The first involves all disagreement cells in a rater × rater cross-tabulation. The second involves one of the triangles of disagreement cells. The third involves the cells that indicate disagreement by one (ordinal) scale unit. For each of these three scenarios, coefficients of disagreement in the form of κ equivalents are derived. The behavior of the coefficients of disagreement in the three situations is studied. The first and the third case pose no particular problem. The κ equivalents and the other coefficients can be interpreted as usual. In the second case, problems arise such that the range of disagreement κs is restricted because the tables are incomplete. Thus, the standard log-frequency model of rater independence is no longer applicable. When the more general models of quasi-independence are used, negative degrees of freedom can result for smaller tables. Simulation results illustrate the characteristics of the coefficients of disagreement for each of the three scenarios. Empirical data examples are given.

APA, Harvard, Vancouver, ISO, and other styles

16

Roldán-Nofuentes, José Antonio, and Saad Bouh Regad. "Estimation of the Average Kappa Coefficient of a Binary Diagnostic Test in the Presence of Partial Verification." Mathematics 9, no. 14 (July 19, 2021): 1694. http://dx.doi.org/10.3390/math9141694.

Full text

Abstract:

The average kappa coefficient of a binary diagnostic test is a measure of the beyond-chance average agreement between the binary diagnostic test and the gold standard, and it depends on the sensitivity and specificity of the diagnostic test and on disease prevalence. In this manuscript the estimation of the average kappa coefficient of a diagnostic test in the presence of verification bias is studied. Confidence intervals for the average kappa coefficient are studied applying the methods of maximum likelihood and multiple imputation by chained equations. Simulation experiments have been carried out to study the asymptotic behaviors of the proposed intervals, given some application rules. The results obtained in our simulation experiments have shown that the multiple imputation by chained equations method provides better results than the maximum likelihood method. A function has been written in R to estimate the average kappa coefficient by applying multiple imputation. The results have been applied to the diagnosis of liver disease.

APA, Harvard, Vancouver, ISO, and other styles

17

Husidic, Edin, Klaus Scherer, Marian Lazar, Horst Fichtner, and Stefaan Poedts. "Toward a Realistic Evaluation of Transport Coefficients in Non-equilibrium Space Plasmas." Astrophysical Journal 927, no. 2 (March 1, 2022): 159. http://dx.doi.org/10.3847/1538-4357/ac4af4.

Full text

Abstract:

Abstract Recent studies have outlined the interest for the evaluation of transport coefficients in space plasmas, where the observed velocity distributions of plasma particles are conditioned not only by the binary collisions, e.g., at low energies, but also by the energization of particles from their interaction with wave turbulence and fluctuations, generating the suprathermal kappa-distributed populations. This paper provides a first estimate of the main transport coefficients based on regularized kappa distributions, which, unlike standard kappa distributions (SKDs), enable macroscopic parameterization without mathematical divergences or physical inconsistencies. All transport coefficients derived here, i.e., the diffusion and mobility coefficients, electric conductivity, thermoelectric coefficient, and thermal conductivity, are finite and well defined for all values of κ > 0. Moreover, for low values of κ (i.e., below the SKD poles), the transport coefficients can be orders of magnitudes higher than the corresponding Maxwellian limits, meaning that significant underestimations can be made if suprathermal electrons are ignored.

APA, Harvard, Vancouver, ISO, and other styles

18

Afhami, Shirin, Mohammad Ali Borumand, Negin Esmailpour Bazzaz, Hiva Saffar, Azar Hadadi, Mahdi Jafary Nezhad, and Nahid Mirzaei Tirabadi. "Antimicrobial resistance pattern of Acinetobacter; a multicenter study, comparing European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standards Institute (CLSI); evaluation of susceptibility testing methods for polymyxin." Immunopathologia Persa 7, no. 1 (July 7, 2020): e04-e04. http://dx.doi.org/10.34172/ipp.2021.04.

Full text

Abstract:

Introduction: Acinetobacter species in clinical isolates cause severe infections including meningitis, bloodstream infection, ventilator-associated pneumonia, and surgical site infections. Objectives: In the present study, we evaluated Acinetobacter drug resistance using both European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standards Institute (CLSI) antimicrobial susceptibility test methods. Materials and Methods: Clinical specimens of 128 patients who were admitted in three referral tertiary care teaching hospitals were enrolled in 2014. Blood and other sterile fluid samples, endotracheal secretion, ulcer, urine and other clinical specimen cultures were included, and microbial resistance of Acinetobacter isolates was determined and compared with disk diffusion and E-test antimicrobial susceptibility methods, using both the EUCAST and CLSI standards. Cohen’s kappa coefficient was also reported. Results: The highest percentage of resistance (96.9%) was found for meropenem and imipenem antimicrobials, and the lowest resistance (82.8%) was found for amikacin. The highest kappa agreement coefficient was for ciprofloxacin (kappa coefficient = 0.783), and the lowest kappa was for amikacin (kappa coefficient = 0.21). Conclusion: According to the results, it is better to consider amikacin as a choice in combination with another effective antimicrobial for treatment of drug resistant Acinetobacter.

APA, Harvard, Vancouver, ISO, and other styles

19

Mishra, Durgesh Kumar, Ashutosh Singh, Sunil Mishra, Priti Singh, and Abhishek Singh. "PM3 Method based QSAR Study of the Derivatives of Thiadiazole and Quinoxaline for Antiepileptic Activity using Topological Descriptors." Asian Journal of Organic & Medicinal Chemistry 7, no. 1 (2022): 99–110. http://dx.doi.org/10.14233/ajomc.2022.ajomc-p370.

Full text

Abstract:

QSAR study of the derivatives of thiadiazole and quinoxaline has been performed for the antiepileptic activity using the topological descriptors viz., molar refractivity, shape index (basic kappa, order 1), shape index (basic kappa, order 2), shape index (basic kappa, order 3), valence connectivity index (order 0, standard), valence connectivity index (order 1, standard) and valence connectivity index (order 2, standard). In the best QSAR model, the descriptors are molar refractivity, shape index (basic kappa, order 1), shape index (basic kappa, order 3) and valence connectivity index (order 0, standard). In this QSAR model, the regression coefficient is 0.872435 and cross-validation coefficient is 0.832189, which indicate that this QSAR model can be used to predict the antiepileptic activity of any compound belonging to this series. QSAR model developed using single descriptor shape index (basic kappa, order 1) or shape index (basic kappa, order 3) or valence connectivity index (order 2, standard) also has good predictive power.

APA, Harvard, Vancouver, ISO, and other styles

20

van Sommeren, Daan D. J. A., C. P. Caulfield, and Andrew W. Woods. "Spatially varying mixing of a passive scalar in a buoyancy-driven turbulent flow." Journal of Fluid Mechanics 742 (February 24, 2014): 701–19. http://dx.doi.org/10.1017/jfm.2014.25.

Full text

Abstract:

AbstractWe perform experiments to study the mixing of passive scalar by a buoyancy-induced turbulent flow in a long narrow vertical tank. The turbulent flow is associated with the downward mixing of a small flux of dense aqueous saline solution into a relatively large upward flux of fresh water. In steady state, the mixing region is of finite extent, and the intensity of the buoyancy-driven mixing is described by a spatially varying turbulent diffusion coefficient $\kappa _v(z)$ which decreases linearly with distance $z$ from the top of the tank. We release a pulse of passive scalar into either the fresh water at the base of the tank, or the saline solution at the top of the tank, and we measure the subsequent mixing of the passive scalar by the flow using image analysis. In both cases, the mixing of the passive scalar (the dye) is well-described by an advection–diffusion equation, using the same turbulent diffusion coefficient $\kappa _v(z)$ associated with the buoyancy-driven mixing of the dynamic scalar. Using this advection–diffusion equation with spatially varying turbulent diffusion coefficient $\kappa _v(z)$, we calculate the residence time distribution (RTD) of a unit mass of passive scalar released as a pulse at the bottom of the tank. The variance in this RTD is equivalent to that produced by a uniform eddy diffusion coefficient with value $\kappa _e= 0.88 \langle \kappa _v \rangle $, where $\langle \kappa _v \rangle $ is the vertically averaged eddy diffusivity. The structure of the RTD is also qualitatively different from that produced by a flow with uniform eddy diffusion coefficient. The RTD using $\kappa _v$ has a larger peak value and smaller values at early times, associated with the reduced diffusivity at the bottom of the tank, and manifested mathematically by a skewness $\gamma _1\approx 1.60$ and an excess kurtosis $\gamma _2\approx 4.19 $ compared to the skewness and excess kurtosis of $\gamma _1\approx 1.46$, $\gamma _2 \approx 3.50$ of the RTD produced by a constant eddy diffusion coefficient with the same variance.

APA, Harvard, Vancouver, ISO, and other styles

21

Strube, Michael J. "A general program for the calculation of the kappa coefficient." Behavior Research Methods, Instruments, & Computers 21, no. 6 (November 1989): 643–44. http://dx.doi.org/10.3758/bf03210592.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Küchenhoff, Helmut, Thomas Augustin, and Anne Kunz. "Partially identified prevalence estimation under misclassification using the kappa coefficient." International Journal of Approximate Reasoning 53, no. 8 (November 2012): 1168–82. http://dx.doi.org/10.1016/j.ijar.2012.06.013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Chabalala, Yingisani, Elhadi Adam, and Khalid Adem Ali. "Machine Learning Classification of Fused Sentinel-1 and Sentinel-2 Image Data towards Mapping Fruit Plantations in Highly Heterogenous Landscapes." Remote Sensing 14, no. 11 (May 31, 2022): 2621. http://dx.doi.org/10.3390/rs14112621.

Full text

Abstract:

Mapping smallholder fruit plantations using optical data is challenging due to morphological landscape heterogeneity and crop types having overlapping spectral signatures. Furthermore, cloud covers limit the use of optical sensing, especially in subtropical climates where they are persistent. This research assessed the effectiveness of Sentinel-1 (S1) and Sentinel-2 (S2) data for mapping fruit trees and co-existing land-use types by using support vector machine (SVM) and random forest (RF) classifiers independently. These classifiers were also applied to fused data from the two sensors. Feature ranks were extracted using the RF mean decrease accuracy (MDA) and forward variable selection (FVS) to identify optimal spectral windows to classify fruit trees. Based on RF MDA and FVS, the SVM classifier resulted in relatively high classification accuracy with overall accuracy (OA) = 0.91.6% and kappa coefficient = 0.91% when applied to the fused satellite data. Application of SVM to S1, S2, S2 selected variables and S1S2 fusion independently produced OA = 27.64, Kappa coefficient = 0.13%; OA= 87%, Kappa coefficient = 86.89%; OA = 69.33, Kappa coefficient = 69. %; OA = 87.01%, Kappa coefficient = 87%, respectively. Results also indicated that the optimal spectral bands for fruit trees mapping are green (B3) and SWIR_2 (B10) for S2, whereas for S1, the vertical-horizontal (VH) polarization band. Including the textural metrics from the VV channel improved crop discrimination and co-existing land use cover types. The fusion approach proved robust and well suited for accurate smallholder fruit plantation mapping.

APA, Harvard, Vancouver, ISO, and other styles

24

Eugenio, Barbara Di, and Michael Glass. "The Kappa Statistic: A Second Look." Computational Linguistics 30, no. 1 (March 2004): 95–101. http://dx.doi.org/10.1162/089120104773633402.

Full text

Abstract:

In recent years, the kappa coefficient of agreement has become the de facto standard for evaluating intercoder agreement for tagging tasks. In this squib, we highlight issues that affect κ and that the community has largely neglected. First, we discuss the assumptions underlying different computations of the expected agreement component of κ. Second, we discuss how prevalence and bias affect the κ measure.

APA, Harvard, Vancouver, ISO, and other styles

25

Selem, Soraya Sant'Ana de Castro, Aline Martins de Carvalho, Eliseu Verly-Junior, Jackeline Venâncio Carlos, Juliana Araujo Teixeira, Dirce Maria Lobo Marchioni, and Regina Mara Fisberg. "Validity and reproducibility of a food frequency questionnaire for adults of São Paulo, Brazil." Revista Brasileira de Epidemiologia 17, no. 4 (December 2014): 852–59. http://dx.doi.org/10.1590/1809-4503201400040005.

Full text

Abstract:

OBJECTIVES: To assess the validity and reproducibility of a food frequency questionnaire developed for estimating the food consumption of adults in São Paulo, Brazil, based population study. METHODS: A sample of individuals aged above 20 years, of both genders, living in São Paulo, was used for the validation study (n = 77) and reproducibility study (n = 74) of the food frequency questionnaire. To verify the validity and reproducibility of energy and 19 nutrients were applied two food frequency questionnaires (60 items) and three 24-hour dietary recalls (24HR - reference method). The validity was verified by Spearman correlation coefficient (crude and de-attenuated) and weighted Kappa, and reproducibility by intraclass correlation coefficients and weighted kappa. RESULTS: In analyzes of validity de-attenuated correlation coefficients ranged from 0.21 (carbohydrate) to 0.74 (energy), and weighted kappa exceeded 0.40 for 30% of the nutrients. Polyunsaturated fat and folate did not show significant correlation and weighted kappa. In reproducibility correlation coefficients ranged from 0.36 (polyunsaturated fat) to 0.69 (calcium), and weighted kappa exceeded 0.40 for 80% of the nutrients. CONCLUSION: The food frequency questionnaire analyzed has good validity and reproducibility for estimating the food consumption of adults in São Paulo compared to the reference method, so it is an appropriate instrument to be used in epidemiological studies on similar populations. Estimates of polyunsaturated fat and folate should be interpreted with caution.

APA, Harvard, Vancouver, ISO, and other styles

26

Felipe, Beatriz Caio, Fernanda Chiguti Yamashita, Amanda Lury Yamashita, Ana Carolina Caio Passoni, Breno Gabriel da Silva, Elen de Souza Tolentino, Mariliani Chicarelli, and Lilian Cristina Vessoni Iwaki. "Problem-based learning in dentistry: Diagnostic capability of dentists in the detection of calcified carotid artery atheroma on digital panoramic radiographs." Research, Society and Development 9, no. 11 (December 1, 2020): e70991110451. http://dx.doi.org/10.33448/rsd-v9i11.10451.

Full text

Abstract:

Objective: The aim of this study was to evaluate the diagnostic capability of dentists in the identification of suggestive images of calcified carotid artery atheroma (CCAA) on panoramic radiographs (PRs) before and after using a problem-based learning method (PBL). Methodology: Five dentists (no specialists in oral and maxillofacial radiology) analyzed 102 digital PRs divided into: PRs with suggestive images of CCAA (n=51) and without suggestive images of CCAA (n=51). After the first analysis, the examiners attended an activity on soft tissue calcifications using the PBL method. Afterwards, they analyzed the 102 PRs again. The results of the analysis were calculated using the Cohen's Kappa Test and the Receptor Operational Characteristic Curves (ROC). Results and Discussion: Regarding examiners’ performance before and after the activity, the intra-examiner test showed reasonable Kappa coefficients (0-0.40). For inter-examiner agreement after the activity, the Kappa coefficient was almost perfect (> 0.80). When comparing examiners’ performance after the activity with a template performed by an experienced radiologist, the Kappa Coefficient was > 0.80 with significant agreement (p<0.05). Conclusion: The precision and the probability of correctly detecting suggestive images of CCAA on PRs increased when the examiners participated in the active pedagogical method. The continuing education of the dentist and how it can make a difference in the systemic health of patients should be considered.

APA, Harvard, Vancouver, ISO, and other styles

27

He, Jie, Du Lyu, Liang He, Yujie Zhang, Xiaoming Xu, Haijie Yi, Qilong Tian, Baoyuan Liu, and Xiaoping Zhang. "Combining Object-Oriented and Deep Learning Methods to Estimate Photosynthetic and Non-Photosynthetic Vegetation Cover in the Desert from Unmanned Aerial Vehicle Images with Consideration of Shadows." Remote Sensing 15, no. 1 (December 25, 2022): 105. http://dx.doi.org/10.3390/rs15010105.

Full text

Abstract:

Soil erosion is a global environmental problem. The rapid monitoring of the coverage changes in and spatial patterns of photosynthetic vegetation (PV) and non-photosynthetic vegetation (NPV) at regional scales can help improve the accuracy of soil erosion evaluations. Three deep learning semantic segmentation models, DeepLabV3+, PSPNet, and U-Net, are often used to extract features from unmanned aerial vehicle (UAV) images; however, their extraction processes are highly dependent on the assignment of massive data labels, which greatly limits their applicability. At the same time, numerous shadows are present in UAV images. It is not clear whether the shaded features can be further classified, nor how much accuracy can be achieved. This study took the Mu Us Desert in northern China as an example with which to explore the feasibility and efficiency of shadow-sensitive PV/NPV classification using the three models. Using the object-oriented classification technique alongside manual correction, 728 labels were produced for deep learning PV/NVP semantic segmentation. ResNet 50 was selected as the backbone network with which to train the sample data. Three models were used in the study; the overall accuracy (OA), the kappa coefficient, and the orthogonal statistic were applied to evaluate their accuracy and efficiency. The results showed that, for six characteristics, the three models achieved OAs of 88.3–91.9% and kappa coefficients of 0.81–0.87. The DeepLabV3+ model was superior, and its accuracy for PV and bare soil (BS) under light conditions exceeded 95%; for the three categories of PV/NPV/BS, it achieved an OA of 94.3% and a kappa coefficient of 0.90, performing slightly better (by ~2.6% (OA) and ~0.05 (kappa coefficient)) than the other two models. The DeepLabV3+ model and corresponding labels were tested in other sites for the same types of features: it achieved OAs of 93.9–95.9% and kappa coefficients of 0.88–0.92. Compared with traditional machine learning methods, such as random forest, the proposed method not only offers a marked improvement in classification accuracy but also realizes the semiautomatic extraction of PV/NPV areas. The results will be useful for land-use planning and land resource management in the areas.

APA, Harvard, Vancouver, ISO, and other styles

28

Skinner, Mark, Chatree Chai-Adisaksopha, Randall Curtis, Neil Frick, Davide Matino, Michael Nichol, Declan Noone, et al. "VP57 Test-Retest Reliability Analysis Of The Patient Reported Outcomes Burdens And Experiences (PROBE) Study Questionnaire Test-Retest Reliability Analysis Of The PROBE Study Questionnaire." International Journal of Technology Assessment in Health Care 33, S1 (2017): 174–75. http://dx.doi.org/10.1017/s0266462317003361.

Full text

Abstract:

INTRODUCTION:The Patient Reported Outcomes Burdens and Experiences (PROBE) questionnaire was developed with direct patient involvement in questionnaire design, conduct and analysis using patient-centered outcomes to assess health status in patients with hemophilia (PWH). Phase 1 confirmed robustness of the methodology and feasibility. Phase 2a investigated individual test-retest reliability. Phase 2b will explore population level reproducibility.METHODS:PWH and non-PWH individuals who attended a hemophilia-related workshop were asked to complete the PROBE questionnaire 3 times (paper-based survey on 2 consecutive days and then a web-based version). Test-retest reliability was analyzed using the percentage agreement and Kappa statistic. Kappa coefficient interpretation .81-1.00 almost perfect, .61- .80 substantial; .41- .60 moderate; .21 -.40 fair; .00 -.20, slight; and < .00 poor agreement.RESULTS:Sixty-three participants from twenty-one countries were enrolled with a median age of 50 (range 14–76) years. Of these, thirty (47.6 percent) were PWH or carriers, thirty-three (52.5 percent) were participants with no known bleeding disorders. On general health domain, Kappa coefficients ranged from .69 to .92, indicating substantial to almost perfect agreement, for all items. Reliability of the web-based questionnaire showed moderate to substantial agreement for all except one item. For the hemophilia-related domain, Kappa coefficients ranged from .5-1.0. Of these, five of eleven items were in perfect agreement (Kappa = 1.0). Reliability of web-based questionnaire items were in substantial to almost perfect agreement. For overall health related quality of life, the EuroQol five dimensions questionnaire (EQ-5D) had Kappa coefficients of .62 to .92. Intraclass correlation coefficient of visual analog scale (VAS) was .90 (95 percent Confidence Interval, CI; .83-.94). Test-retest reliability was comparable between hemophilia patients and participants with no known bleed.CONCLUSIONS:Phase 2a demonstrated individual test-retest reliability and suggests PROBE is a reliable tool to assess Patient Reported Outcomes in PWH. The Web-based questionnaire has an acceptable agreement with the standard paper-based version in all domains. PROBE Phase 2b, to demonstrate reproducibility at the population level, is on-going. To date, 1,039 participants have been recruited from 10 countries.

APA, Harvard, Vancouver, ISO, and other styles

29

DOĞAN, İsmet, and Nurhan DOĞAN. "Evaluation of Cohen Kappa Coefficient and Distinguishability for Binary Data: A Simulation Study." Turkiye Klinikleri Journal of Biostatistics 14, no. 3 (2022): 190–98. http://dx.doi.org/10.5336/biostatic.2022-89212.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Islami, F. A., S. D. Tarigan, E. D. Wahjunie, and B. D. Dasanto. "Accuracy Assessment of Land Use Change Analysis Using Google Earth in Sadar Watershed Mojokerto Regency." IOP Conference Series: Earth and Environmental Science 950, no. 1 (January 1, 2022): 012091. http://dx.doi.org/10.1088/1755-1315/950/1/012091.

Full text

Abstract:

Abstract Mojokerto Regency is one of the regencies in East Java with a high population growth rate of around 0.96%, thus encouraging significant land use changes on built-up areas. Classifying remote sensing imageries to obtain reliable and accurate land use and land cover (LULC) information remains a challenge that depends on many factors such as complexity of the landscape, the remote sensing data selected, image processing, and classification methods. This study examined the accuracy assessment of LULC classification using Google Earth in Sadar Watershed, Mojokerto, East Java Indonesia for the years 2010, 2015, and 2020. The land use was classified into five categories; those are agriculture land (paddy field, field, and plantation), non-agriculture land (forest land, bushland, grazing land), bare land, settlement land, and water bodies. Around 85 random points were generated in ArcGIS and verified with Google Earth. The results showed that the Overall Accuracy of LULCC for 2010 was 80.2% and Kappa Coefficient was 0.74; for 2015, the Overall Accuracy was 85.3% and Kappa Coefficient was 0.8, and for 2020, the Overall Accuracy was 84.0%, and Kappa Coefficient was 0.79. All accuracy is considered as good categorized and acceptable in both overall accuracy and Kappa Coefficient.

APA, Harvard, Vancouver, ISO, and other styles

31

MORI, Ryota. "A Proposal for Measurement Methods of Mental Models using Kappa Coefficient." Transactions of Japan Society of Kansei Engineering 15, no. 4 (2016): 537–43. http://dx.doi.org/10.5057/jjske.tjske-d-16-00019.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Vanbelle, S., and A. Albert. "A note on the linearly weighted kappa coefficient for ordinal scales." Statistical Methodology 6, no. 2 (March 2009): 157–63. http://dx.doi.org/10.1016/j.stamet.2008.06.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Petersen, Ina Sleimann, and Hygiene Henrik Wachmann. "Using the Kappa Coefficient as a Measure of Reliability or Reproducibility." Chest 114, no. 3 (September 1998): 946–47. http://dx.doi.org/10.1378/chest.114.3.946-a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Nofuentes, J. A. Roldán, J. D. Luna del Castillo, and M. A. Montero Alonso. "Confidence Intervals of Weighted Kappa Coefficient of a Binary Diagnostic Test." Communications in Statistics - Simulation and Computation 38, no. 8 (July 22, 2009): 1562–78. http://dx.doi.org/10.1080/03610910903039473.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Haley, Stephen M., and J. Scott Osberg. "Kappa Coefficient Calculation Using Multiple Ratings Per Subject: A Special Communication." Physical Therapy 69, no. 11 (November 1, 1989): 970–74. http://dx.doi.org/10.1093/ptj/69.11.970.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Guo, Ying, and Amita K. Manatunga. "Modeling the Agreement of Discrete Bivariate Survival Times using Kappa Coefficient." Lifetime Data Analysis 11, no. 3 (September 2005): 309–32. http://dx.doi.org/10.1007/s10985-005-2965-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

SHOUKRI, M. M., and I. U. H. MIAN. "MAXIMUM LIKELIHOOD ESTIMATION OF THE KAPPA COEFFICIENT FROM BIVARIATE LOGISTIC REGRESSION." Statistics in Medicine 15, no. 13 (July 15, 1996): 1409–19. http://dx.doi.org/10.1002/(sici)1097-0258(19960715)15:13<1409::aid-sim269>3.0.co;2-n.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Ipach, Ingmar, Eva-Maria Arlt, Falk Mittag, Beate Kunze, Petra Wolf, and Torsten Kluba. "A Classification-System Improves the Intra- and Interobserver Reliability of Radiographic Diagnosis of “Pistol-Grip-Deformity”." HIP International 21, no. 6 (November 2011): 732–39. http://dx.doi.org/10.5301/hip.2011.8821.

Full text

Abstract:

Early detection of pistol-grip-deformity may be beneficial in optimising the outcome and the cost effectiveness of surgery. It is important to identify reliable radiographic parameters in assessing femoro-acetabular impingement (FAI) to develop a treatment algorithm. Radiographs of 47 patients ranging from “pistol grip deformity” to a normal head-neck-junction were measured for alpha angle and head ratio, and then classified by two different observers. The Bland-Altman plot was used for inter- and intraobserver agreement of alpha angle and head ratio. Inter- and intraobserver agreement for classification of “pistol grip deformity” was determined using weighted Cohen's kappa coefficient. Observer I achieved a kappa coefficient of 0.97. Observer II achieved a kappa coefficient of 0.92. An interobserver kappa coefficient between 0.87 and 0.92 was achieved by using a classification system. By testing for interobserver agreement, a bias of –0.004 with an upper limit of 0.461 and a lower limit of –0.47 was seen for the ratio and a bias of –3.7 with an upper limit of 17.2 and a lower limit of –24.6 for the alpha angle. Therefore, poor results were seen for intra- and interobserver reliability by using only a single plane for classification of “pistol grip deformity”. The strength of agreement could be improved by using a classification system (based on two planes).

APA, Harvard, Vancouver, ISO, and other styles

39

Fresneda, Mariano J., Juan J. Dere, Carlos H. Yacuzzi, and Matías Costa Paz. "ISAKOS Classification of Meniscal Tears. Intra and Interobserver Reliability." Orthopaedic Journal of Sports Medicine 2, no. 12_suppl4 (December 1, 2014): 2325967114S0023. http://dx.doi.org/10.1177/2325967114s00239.

Full text

Abstract:

Objectives: To analyze the intra and interobserverreliability of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification of meniscal tears. Methods: Thearthroscopic classification of meniscal lesions created by the ISAKOS was used. Thirty one arthroscopic videos, made between June and December 2013,with different meniscal tear characteristics were analyzedby three orthopedic surgeons (two specialists in knee surgery and a fellowship), twice at an interval of 30 days. The Kappa Coefficients (k) was used to assess the intraobserver reliability and intraclass correlation coefficient (ICC) for interobserverreliability. Results: The averageintraobserver reliability was for the first observer 51%, the second 65% and the third 58%, reaching moderate agreement according to the Kappa coefficient used by Landis and Koch. Regarding interobserver reliability, good agreement (ICC = 0.71) was obtained as the intraclass correlation coefficient. The whole results were significantlystatical (p <0.05). Conclusion: While this classification provides a detailed description of meniscal lesions, the intraobserver reliability did not reach the optimum values obtained despite having on average a moderate agreement. However interobserver reliability results showed on average 70% of agreement (good agreement), which can affirm that the agreement and interobserver reliability is acceptable.

APA, Harvard, Vancouver, ISO, and other styles

40

Mello, Paulo Roberto Bezerra de, Claudia de Souza Ozores Caldas, Sandra Coenga de Souza, and Ageo Mário Cândido da Silva. "The agreement between two screening tests for language evaluation in premature and low weight children." Revista Brasileira de Saúde Materno Infantil 16, no. 3 (September 2016): 295–302. http://dx.doi.org/10.1590/1806-93042016000300005.

Full text

Abstract:

Abstract Objectives: to evaluate the agreement of the results in two screening tests on children's development - Denver II and Early Language Milestone Scale (ELM) aged two to three years old, born prematurely and with low weight. Methods: two screening instruments: Denver II and ELM were applied for the development in an observational cross-sectional descriptive study. The agreement between Denver II Test and its language sector and ELM were assessed by Kappa coefficient. Results: 77 children evaluated, 36.3% had an overall loss of the development performed by Denver II and 32.5% loss of the language by ELM. The agreement between the results of Denver II test considering all sectors versus ELM showed Kappa coefficient of 0.856 (p<0.001) and considering only the language sector of Denver II versus ELM, the Kappa coefficient was 0.886 (p<0.001). Conclusions: the developmental impairment observed in the children studied by assessing Denver II and through its language sector showed agreement with changes in the language abilities observed in ELM.

APA, Harvard, Vancouver, ISO, and other styles

41

Wieland, Marc, and Sandro Martinis. "A Modular Processing Chain for Automated Flood Monitoring from Multi-Spectral Satellite Data." Remote Sensing 11, no. 19 (October 8, 2019): 2330. http://dx.doi.org/10.3390/rs11192330.

Full text

Abstract:

Emergency responders frequently request satellite-based crisis information for flood monitoring to target the often-limited resources and to prioritize response actions throughout a disaster situation. We present a generic processing chain that covers all modules required for operational flood monitoring from multi-spectral satellite data. This includes data search, ingestion and preparation, water segmentation and mapping of flooded areas. Segmentation of the water extent is done by a convolutional neural network that has been trained on a global dataset of Landsat TM, ETM+, OLI and Sentinel-2 images. Clouds, cloud shadows and snow/ice are specifically handled by the network to remove potential biases from downstream analysis. Compared to previous work in this direction, the method does not require atmospheric correction or post-processing and does not rely on ancillary data. Our method achieves an Overall Accuracy (OA) of 0.93, Kappa of 0.87 and Dice coefficient of 0.90. It outperforms a widely used Random Forest classifier and a Normalized Difference Water Index (NDWI) threshold method. We introduce an adaptable reference water mask that is derived by time-series analysis of archive imagery to distinguish flood from permanent water. When tested against manually produced rapid mapping products for three flood disasters (Germany 2013, China 2016 and Peru 2017), the method achieves ≥ 0.92 OA, ≥ 0.86 Kappa and ≥ 0.90 Dice coefficient. Furthermore, we present a flood monitoring application centred on Bihar, India. The processing chain produces very high OA (0.94), Kappa (0.92) and Dice coefficient (0.97) and shows consistent performance throughout a monitoring period of one year that involves 19 Landsat OLI ( μ Kappa = 0.92 and σ Kappa = 0.07 ) and 61 Sentinel-2 images ( μ Kappa = 0.92 , σ Kappa = 0.05 ). Moreover, we show that the mean effective revisit period (considering cloud cover) can be improved significantly by multi-sensor combination (three days with Sentinel-1, Sentinel-2, and Landsat OLI).

APA, Harvard, Vancouver, ISO, and other styles

42

Syauqy, Ahmad, Diana Nur Afifah, Rachma Purwanti, Choirun Nissa, Deny Yudi Fitranti, and Jane C. J. Chao. "Reproducibility and Validity of a Food Frequency Questionnaire (FFQ) Developed for Middle-Aged and Older Adults in Semarang, Indonesia." Nutrients 13, no. 11 (November 20, 2021): 4163. http://dx.doi.org/10.3390/nu13114163.

Full text

Abstract:

We assessed the reproducibility and validity of a food frequency questionnaire (FFQ) among middle-aged and older adults in Semarang, Indonesia. A total of 259 subjects aged 40–80 years completed two FFQs (nine-month apart) and nine 24 h dietary recalls (24HDRs, as a reference method). The reproducibility of the FFQ was analyzed using correlation coefficient, intra-class correlation coefficient (ICC), weighted kappa statistics and misclassification analysis. The validity was estimated by comparing the data acquired from FFQ1 and 24HDRs. The crude Pearson’s correlation coefficients and ICC for total energy and nutrients between FFQ1 and FFQ2 ranged from 0.50 to 0.81 and 0.44 to 0.78, respectively. Energy adjustment decreased the correlation coefficients for most nutrients. The crude, energy-adjusted and de-attenuated correlation coefficients for FFQ1 and 24HDRs ranged from 0.41 to 0.70, 0.31 to 0.89 and 0.54 to 0.82, respectively. The agreement rates for the same or adjacent quartile classifications were 81.1–94.6% for two FFQs and 80.7–89.6% for FFQ1 and 24HDRs. The weighted kappa values were 0.21 to 0.42 for two FFQs and 0.20 to 0.34 for FFQ1 and 24HDRs. A positive mean difference was found in the Bland–Altman analyses for energy and macronutrients. The FFQ could be acceptable for nutritional epidemiology study among Indonesians.

APA, Harvard, Vancouver, ISO, and other styles

43

Hosen, Md Ismail, Nathalie Forey, Geoffroy Durand, Catherine Voegele, Selin Bilici, Patrice Hodonou Avogbe, Tiffany Myriam Delhomme, et al. "Development of Sensitive Droplet Digital PCR Assays for Detecting Urinary TERT Promoter Mutations as Non-Invasive Biomarkers for Detection of Urothelial Cancer." Cancers 12, no. 12 (November 27, 2020): 3541. http://dx.doi.org/10.3390/cancers12123541.

Full text

Abstract:

Somatic mutations in the telomerase reverse transcriptase (TERT) promoter regions are frequent events in urothelial cancer (UC) and their detection in urine (supernatant cell-free DNA or DNA from exfoliated cells) could serve as putative non-invasive biomarkers for UC detection and monitoring. However, detecting these tumor-borne mutations in urine requires highly sensitive methods, capable of measuring low-level mutations. In this study, we developed sensitive droplet digital PCR (ddPCR) assays for detecting TERT promoter mutations (C228T, C228A, CC242-243TT, and C250T). We tested the C228T and C250T ddPCR assays on all samples with sufficient quantity of urinary DNA (urine supernatant cell-free DNA (US cfDNA) or urine pellet cellular DNA (UP cellDNA)) from the DIAGURO (n = 89/93 cases and n = 92/94 controls) and from the IPO-PORTO (n = 49/50 cases and n = 50/50 controls) series that were previously screened with the UroMuTERT assay and compared the performance of the two approaches. In the DIAGURO series, the sensitivity and specificity of the ddPCR assays for detecting UC using either US cfDNA or UP cellDNA were 86.8% and 92.4%. The sensitivity was slightly higher than that of the UroMuTERT assay in the IPO-PORTO series (67.4% vs. 65.3%, respectively), but not in the DIAGURO series (86.8% vs. 90.7%). The specificity was 100% in the IPO-PORTO controls for both the UroMuTERT and ddPCR assays, whereas in the DIAGURO series, the specificity dropped for ddPCR (92.4% versus 95.6%). Overall, an almost perfect agreement between the two methods was observed for both US cfDNA (n = 164; kappa coefficient of 0.91) and UP cellDNA (n = 280; kappa coefficient of 0.94). In a large independent series of serial urine samples from DIAGURO follow-up BC cases (n = 394), the agreement between ddPCR and UroMuTERT was (i) strong (kappa coefficient of 0.87), regardless of urine DNA types (kappa coefficient 0.89 for US cfDNA and 0.85 for UP cellDNA), (ii) the highest for samples with mutant allelic fractions (MAFs) > 2% (kappa coefficient of 0.99) and (iii) only minimal for the samples with the lowest MAFs (< 0.5%; kappa coefficient 0.32). Altogether, our results indicate that the two methods (ddPCR and UroMuTERT) for detecting urinary TERT promoter mutations are comparable and that the discrepancies relate to the detection of low-allelic fraction mutations. The simplicity of the ddPCR assays makes them suitable for implementation in clinical settings.

APA, Harvard, Vancouver, ISO, and other styles

44

Hiraga, Kaoru, and Tamotsu Ikeda. "On the Kohnen plus space for Hilbert modular forms of half-integral weight I." Compositio Mathematica 149, no. 12 (September 6, 2013): 1963–2010. http://dx.doi.org/10.1112/s0010437x13007276.

Full text

Abstract:

AbstractIn this paper, we construct a generalization of the Kohnen plus space for Hilbert modular forms of half-integral weight. The Kohnen plus space can be characterized by the eigenspace of a certain Hecke operator. It can be also characterized by the behavior of the Fourier coefficients. For example, in the parallel weight case, a modular form of weight $\kappa + (1/ 2)$ with $\xi \mathrm{th} $ Fourier coefficient $c(\xi )$ belongs to the Kohnen plus space if and only if $c(\xi )= 0$ unless $\mathop{(- 1)}\nolimits ^{\kappa } \xi $ is congruent to a square modulo $4$. The Kohnen subspace is isomorphic to a certain space of Jacobi forms. We also prove a generalization of the Kohnen–Zagier formula.

APA, Harvard, Vancouver, ISO, and other styles

45

Kane-Gill, Sandra L., Levent Kirisci, and Dev S. Pathak. "Are the Naranjo Criteria Reliable and Valid for Determination of Adverse Drug Reactions in the Intensive Care Unit?" Annals of Pharmacotherapy 39, no. 11 (November 2005): 1823–27. http://dx.doi.org/10.1345/aph.1g177.

Full text

Abstract:

BACKGROUND The Naranjo criteria are frequently used for determination of causality for suspected adverse drug reactions (ADRs); however, the psychometric properties have not been studied in the critically ill. OBJECTIVE To evaluate the reliability and validity of the Naranjo criteria for ADR determination in the intensive care unit (ICU). METHODS All patients admitted to a surgical ICU during a 3-month period were enrolled. Four raters independently reviewed 142 suspected ADRs using the Naranjo criteria (review 1). Raters evaluated the 142 suspected ADRs 3–4 weeks later, again using the Naranjo criteria (review 2). Inter-rater reliability was tested using the kappa statistic. The weighted kappa statistic was calculated between reviews 1 and 2 for the intra-rater reliability of each rater. Cronbach alpha was computed to assess the inter-item consistency correlation. The Naranjo criteria were compared with expert opinion for criterion validity for each rater and reported as a Spearman rank (rs) coefficient. RESULTS The kappa statistic ranged from 0.14 to 0.33, reflecting poor inter-rater agreement. The weighted kappa within raters was 0.5402–0.9371. The Cronbach alpha ranged from 0.443 to 0.660, which is considered moderate to good. The rs coefficient range was 0.385–0.545; all rs coefficients were statistically significant (p < 0.05). CONCLUSIONS Inter-rater reliability is marginal; however, within-rater evaluation appears to be consistent. The inter-item correlation is expected to be higher since all questions pertain to ADRs. Overall, the Naranjo criteria need modification for use in the ICU to improve reliability, validity, and clinical usefulness.

APA, Harvard, Vancouver, ISO, and other styles

46

CASTRO, CAÍQUE JAUHAR DE, LUIS EDUARDO CARELLI TEIXEIRA DA SILVA, LUIZ EDUARDO ALMEIDA, ALDERICO GIRÃO CAMPOS DE BARROS, ROBSON TEIXEIRA VITAL, MÁRCIA MARIA RODRIGUES JARDIM, and GIULIANA VASCONCELOS DE SOUZA FONSECA. "INTRA- AND INTEROBSERVER ANALYSIS OF PEDICLE SCREW PLACEMENT IN SCOLIOSIS CORRECTION." Coluna/Columna 19, no. 3 (July 2020): 172–75. http://dx.doi.org/10.1590/s1808-185120201903224255.

Full text

Abstract:

ABSTRACT Objective To establish the statistical interobserver and intraobserver concordance of thoracic pedicle screw placement in scoliosis surgery, with a 4-week interval between the two analyses. Methods Of 55 patients that evaluated the intra- and interobserver concordances of the screw positions (according to the Abul-Kasim classification) using the Kappa coefficient. Results The intraobserver concordance ranged from a Kappa coefficient of 0.516 to 0.889 (“moderate” to “almost perfect”) between the two analyses performed four weeks apart. Interobserver concordance ranged from 0.379 to 0.633 (“reasonable” to “strong”). Conclusion The intraobserver concordance was always greater than the interobserver concordance. No concordance coefficient was classified as “insignificant” or “weak”. Level of Evidence III; Retrospective study.

APA, Harvard, Vancouver, ISO, and other styles

47

Wu, Yanan, Jing Liu, Baolin He, Xiaotong Zhang, and Lu Yu. "Adaptive Filtering Improved Apnea Detection Performance Using Tracheal Sounds in Noisy Environment: A Simulation Study." BioMed Research International 2020 (May 27, 2020): 1–8. http://dx.doi.org/10.1155/2020/7429345.

Full text

Abstract:

Objective. Tracheal sounds were used to detect apnea on various occasions. However, ambient noises can contaminate tracheal sounds which result in poor performance of apnea detection. The objective of this paper was to apply the adaptive filtering (AF) algorithm to improve the quality of tracheal sounds and examine the accuracy of the apnea detection algorithm using tracheal sounds after AF. Method. Tracheal sounds were acquired using a primary microphone encased in a plastic bell, and the ambient noises were collected using a reference microphone resting outside the plastic bell in quiet and noisy environments, respectively. Simultaneously, the flow pressure signals and thoracic and abdominal movement were obtained as the standard signals to determine apnea events. Then, the normalized least mean square (NLMS) AF algorithm was applied to the tracheal sounds mixed with noises. Finally, the algorithm of apnea detection was used to the tracheal sounds with AF and the tracheal sounds without AF. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and Cohen’s kappa coefficient of apnea detection were calculated. Results. Forty-six healthy subjects, aged 18-35 years and with BMI<21.4, were included in the study. The apnea detection performance using tracheal sounds was as follows: in the quiet environment, the tracheal sounds without AF detected apnea with 97.2% sensitivity, 99.9% specificity, 99.8% PPV, 99.4% NPV, 99.5% accuracy, and 0.982 kappa coefficient. The tracheal sounds with AF detected apnea with 98.2% sensitivity, 99.9% specificity, 99.4% PPV, 99.6% NPV, 99.6% accuracy, and 0.985 kappa coefficient. While in the noisy environment, the tracheal sounds without AF detected apnea with 81.1% sensitivity, 96.9% specificity, 85.1% PPV, 96% NPV, 94.2% accuracy, and 0.795 kappa coefficient and the tracheal sounds with AF detected apnea with 91.5% sensitivity, 97.4% specificity, 88.4% PPV, 98.2% NPV, 96.4% accuracy, and 0.877 kappa coefficient. Conclusion. The performance of apnea detection using tracheal sounds with the NLMS AF algorithm in the noisy environment proved to be accurate and reliable. The AF technology could be applied to the respiratory monitoring using tracheal sounds.

APA, Harvard, Vancouver, ISO, and other styles

48

Sim, Julius, and Chris C. Wright. "The Kappa Statistic in Reliability Studies: Use, Interpretation, and Sample Size Requirements." Physical Therapy 85, no. 3 (March 1, 2005): 257–68. http://dx.doi.org/10.1093/ptj/85.3.257.

Full text

Abstract:

Abstract Purpose. This article examines and illustrates the use and interpretation of the kappa statistic in musculoskeletal research. Summary of Key Points. The reliability of clinicians' ratings is an important consideration in areas such as diagnosis and the interpretation of examination findings. Often, these ratings lie on a nominal or an ordinal scale. For such data, the kappa coefficient is an appropriate measure of reliability. Kappa is defined, in both weighted and unweighted forms, and its use is illustrated with examples from musculoskeletal research. Factors that can influence the magnitude of kappa (prevalence, bias, and nonindependent ratings) are discussed, and ways of evaluating the magnitude of an obtained kappa are considered. The issue of statistical testing of kappa is considered, including the use of confidence intervals, and appropriate sample sizes for reliability studies using kappa are tabulated. Conclusions. The article concludes with recommendations for the use and interpretation of kappa.

APA, Harvard, Vancouver, ISO, and other styles

49

Spyratos, Spyridon, Demetris Stathakis, Michael Lutz, and Chrisa Tsinaraki. "Using Foursquare place data for estimating building block use." Environment and Planning B: Urban Analytics and City Science 44, no. 4 (July 27, 2016): 693–717. http://dx.doi.org/10.1177/0265813516637607.

Full text

Abstract:

Information about the land use of built-up areas is required for the comprehensive planning and management of cities. However, due to the high cost of the land use surveys, land use data is out-dated or not available for many cities. Therefore, we propose the reuse of up-to-date and low-cost place data from social media applications for land use mapping purposes. As main case study, we used Foursquare place data for estimating nonresidential building block use in the city of Amsterdam. Based on the Foursquare place categories, we estimated the use of 9827 building blocks, and we compared the classification results with a reference building block use dataset. Our evaluation metric is the kappa coefficient, which determines if the classification results are significantly better than a random guess result. Using the optimal set of parameter values, we achieved the highest kappa coefficient values for the land use categories “ hotels, restaurants and cafes” (0.76) and “ retail” (0.65). The lowest kappa coefficients were found for the land use categories “ industries” and “ storage and unclear”. We have also applied the methodology in another case study area, the city of Varese in Italy, where we had similar accuracy results. We therefore conclude that Foursquare place data can be trusted only for the estimation of particular land use categories.

APA, Harvard, Vancouver, ISO, and other styles

50

Sharma, Abhishek, and Tarun Gulati. "Change Detection from Remotely Sensed Images Based on Stationary Wavelet Transform." International Journal of Electrical and Computer Engineering (IJECE) 7, no. 6 (December 1, 2017): 3395. http://dx.doi.org/10.11591/ijece.v7i6.pp3395-3401.

Full text

Abstract:

The major issue of concern in change detection process is the accuracy of the algorithm to recover changed and unchanged pixels. The fusion rules presented in the existing methods could not integrate the features accurately which results in more number of false alarms and speckle noise in the output image. This paper proposes an algorithm which fuses two multi-temporal images through proposed set of fusion rules in stationary wavelet transform. In the first step, the source images obtained from log ratio and mean ratio operators are decomposed into three high frequency sub-bands and one low frequency sub-band by stationary wavelet transform. Then, proposed fusion rules for low and high frequency sub-bands are applied on the coefficient maps to get the fused wavelet coefficients map. The fused image is recovered by applying the inverse stationary wavelet transform (ISWT) on the fused coefficient map. Finally, the changed and unchanged areas are classified using Fuzzy c means clustering. The performance of the algorithm is calculated in terms of percentage correct classification (PCC), overall error (OE) and Kappa coefficient (K<sub>c</sub>). The qualitative and quantitative results prove that the proposed method offers least error, highest accuracy and Kappa value as compare to its preexistences.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Kappa coefficient'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles