Research interests.

  • Statistics:
    • Mathematical Statistics.
      • Estimation theory. Density, distribution and hazard rate function estimation. Particular focus in kernel based methods and automatic bandwidth selection.
      • Statistical Inference. Development of hypothesis tests for goodness of fit, or assessment of symmetry of densities.
    • Computational Statistics. Applications of bootstrap and cross validation based methods in mathematical statistics.
    • In addition, a wide variety of miscellaneous topics in statistics, including applications.
  • Probability:
    • Applications of Martingales and Edgeworth Expansions to statistical inference.
    • Probabilistic bounds.

    Publications in international peer reviewed academic journals.

    1. D. Bagkavos and A. Kalamatianou, Analysis of duration of studies data by kernel methods, Communications in dependability and quality management, 10(2): 19-27, (2007).
    2. D. Bagkavos and P.N. Patil, Local polynomial fitting in failure rate estimation, IEEE Transactions on reliability, (57): 41-52, (2008). S-plus code.
    3. D. Bagkavos and P.N. Patil, Variable bandwidths for nonparametric hazard rate estimation, Communications in Statistics, Theory and Methods, (38): 1055-1078, (2009). S-plus code.
    4. D. Bagkavos, Transformations in hazard rate estimation, Journal of Nonparametric Statistics, (20): 721-738, (2008). S-plus code.
    5. D. Bagkavos, Local Linear Hazard Rate Estimation And Bandwidth Selection, Annals of the Institute of Statistical Mathematics, (63), 1019-1046, (2011).
    6. D. Bagkavos, Local linear variable bandwidth hazard rate estimation, Journal of Statistical Computation and Simulation, (81), 1517-1531, (2011). S-plus code.
    7. P.N. Patil, P.P. Patil and D. Bagkavos, A Measure of Asymmetry, Statistical papers, (53), 971-985, (2012). S-plus code.
    8. P.N. Patil and D. Bagkavos, Semiparametric Smoothing of Discrete Failure Time Data, Biometrical Journal, (54), 5-19, (2012). S-plus code. Sterilization Data.
    9. D. Bagkavos and D. Ioannidis, Smooth confidence intervals for the survival function under random right censoring, Electronic Journal of Statistics, (6), 843-860, (2012).
    10. P.N. Patil and D. Bagkavos, Histogram for Hazard Rate Estimation, Sankhya B, (74), 286-301, (2013). S-plus code.
    11. D. Bagkavos, D. Ioannides and A. Kalamatianou, A goodness of fit test for the survival function under random right censoring, Electronic Journal of Statistics, (7), 2550-2576, (2013). R code.
    12. P.N. Patil, D. Bagkavos and A.T.A. Wood, A measure of asymmetry based on a new necessary and sufficient condition for symmetry, Sankhya, (76), 123-145, (2014). S-plus code.
    13. H. Hua, P.N. Patil and D. Bagkavos, Semiparametric smoothing approach to hazard rate estimation, Journal of Nonparametric Statistics, (26), 669-693, (2017).
    14. D. Bagkavos and P.N. Patil, A new test of bivariate independence, Journal of Multivariate Analysis, (160), 117-133, (2017). R code.
    15. H. Hua, P.N. Patil and D. Bagkavos, An L1 analysis of a kernel-based hazard rate estimator, Australian and New Zealand Journal of Statistics, (60), 43-64, (2018).
    16. F. Alevizos, D. Bagkavos and D. Ioannides, Efficient estimation of a distribution based on censored data, Statistics and Probability Letters, (145), 359-364 (2019).
    17. D. Bagkavos and D. Ioannides, Fixed design local polynomial smoothing and bandwidth selection for right censored data, Computational Statistics and Data Analysis, (153), 107064 (2021).
    18. D. Bagkavos and P.N. Patil, Improving the Wilcoxon signed rank test by a kernel smooth probability integral transformation, Statistics and Probability Letters (171), 109026 (2021).
    19. P. Economou, A. Batsidis, G. Tzavelas and D. Bagkavos, Hypothesis testing for the population mean and variance based on r-size biased samples, Statistics, (55), 894-924, (2021).
    20. D. Bagkavos and D. Ioannides, Local polynomial smoothing based on the Kaplan-Meier estimate, Journal of Statistical Planning and Inference, (221), 212-229, (2022).
    21. D. Bagkavos, P.N. Patil and A.T.A Wood, Nonparametric goodness-of-fit testing for a continuous multivariate parametric model, Journal of Multivariate Analysis, (196), 105182, (2023).
    22. D. Bagkavos and P.N. Patil, Goodness-of-fit testing for normal mixture densities, Computational Statistics and Data Analysis, (188), 107815, (2023).
    23. D. Bagkavos, M. Guillen and J.P. Nielsen, Nonparametric conditional survival function estimation and plug-in bandwidth selection with multiple covariates, TEST, (2024). R code.

    Selected publications in peer reviewed conference proceedings.

    1. D. Bagkavos (2013): Transformations In Hazard Rate Estimation For Heavy-Tailed Data, In: Bakhtadze, N., Chernyshov, K., Dolgui, A. and Lototsky, V. (Eds.). 7th IFAC Conference on Manufacturing Modelling, Management and Control, International Federation of Automatic Control, St. Petersburg, Russia, Springer. R code. DFL data.
    2. P.N. Patil and D. Bagkavos (2014): Power Assessment of a New Test of Independence, In: Akritas M., Lahiri S., Politis D. (eds) Topics in Nonparametric Statistics. Springer Proceedings in Mathematics and Statistics, vol 74. Springer, New York, NY.
    3. D. Bagkavos, P.N. Patil and A.T.A. Wood (2016): A Numerical Study of the Power Function of a New Symmetry Test, In: Cao R., Gonzalez Manteiga W., Romo J. (eds) Nonparametric Statistics. Springer Proceedings in Mathematics and Statistics, vol 175. Springer, Cham.
    4. D. Bagkavos and P.N. Patil (2020): A Kernel Goodness-of-fit Test for Maximum Likelihood Density Estimates of Normal Mixtures, In: La Rocca M., Liseo B., Salmaso L. (eds) Nonparametric Statistics. ISNPS 2018. Springer Proceedings in Mathematics and Statistics, vol 339. Springer, Cham.
    5. D. Ioannides and D. Bagkavos (2020): Smooth nonparametric survival analysis, In: La Rocca M., Liseo B., Salmaso L. (eds) Nonparametric Statistics. ISNPS 2018. Springer Proceedings in Mathematics and Statistics, vol 339. Springer, Cham.

    Contributed R packages (CRAN).

    1. NPHazardRate: Functions and examples for histogram, kernel (classical, variable bandwidth, transformations based, local linear), discrete and semiparametric hazard rate estimators. The package implements the majority of methods and techniques of articles 2, 3, 4, 5, 8, 9, 15, 17 and 20.
    2. asymmetry.measures: Functions and examples for the weak and strong asymmetry measures developed in articles 7 and 12.
    3. RSizeBiased: Functions and examples for testing hypothesis about the population mean and variance on samples drawn by r-size biased sampling schemes. The package implements the methods and techniques of article 19.
    4. L2DensityGoFtest: Provides functions for the implementation of a density goodness-of-fit test, based on piecewise approximation of the L2 distance. The package implements the methods and techniques of article 21.
    5. HQM: Provides a nonparametric smoothed kernel density estimator for the future conditional hazard when time-dependent covariates are present. It also provides pointwise and uniform confidence bands and a bandwidth selection.

    Refereed for:

    Test (3), Journal of Statistical Planning and Inference (3), Computational Statistics and Data Analysis (3), Statistics and Probability Letters (3), Communications in Statistics - Theory and Methods (3), Computational Statistics (3), Metrika (3), Communications in Statistics - Simulation and Computation (3), Journal of Nonparametric Statistics (2), Journal of the Royal Statistical Society, Section A (1), Journal of the Royal Statistical Society Section B (1), Journal of Applied Statistics (1), Australian and New Zealand Journal of Statistics (1), Journal of the Korean Statistical Society (1), Statistical Papers (1), Communications in Statistics - Case studies and Data analysis (1), Journal of Computational and Applied Mathematics (1), Fuzzy Sets and Systems (1).