Research Publication

Manuscripts

1. Gotherwal, D. and Ranjan, P. (2025), "Systematic Literature Review of Verification and Validation of Simulation Models in Business and Manufacturing using Topic Modeling" (submitted).

2. Danish, S., Ranjan, P. and Kumar, A. (2025) "Post-Grant Patent Vulnerability in India: An Empirical Analysis of Litigation and Renewal Outcomes" (submitted).

R packages

1. Spencer, N., Ranjan, P. and Mendivil, F. (2020). "IsoCheck: Isomorphism Check for Multi-Stage Factorial Designs with Randomization Restrictions." R package version 0.1.0. https://CRAN.R-project.org/package=IsoCheck

2. Zhang, R. Lin, C.D., and Ranjan, P. (2018). "DynamicGP: Local Gaussian Process Model for Large-Scale Dynamic Computer Experiments." R package. https://CRAN.R-project.org/package=DynamicGP

3. MacDonald, K.B., Chipman, H. and Ranjan, P. (2012), “GPfit: A Computationally Stable Approach of Fitting a Gaussian Process Model to Deterministic Simulator Outputs”. R package. https://CRAN.R-project.org/package=GPfit 

Publications

1. Mukherjee, S., Ranjan, P. and Bhattacharya, J. (2025), "Assessing the influence of social media feedback on travelers’ future trip-planning behavior: A multi-model machine learning approach" Asia Pacific Journal of Tourism Research (in press). [https://doi.org/10.1080/10941665.2025.2574034]

2. Lin, C.D. and Ranjan, P. (2025), "Adaptive Designs for Computer Experiments", Handbook of Statistical Methods for Computer Models Uncertainty Quantification, Chapman & Hall/CRC  (in press).

3. Shahrokhian, A., Deng, X., Lin, C.D., Ranjan, P., and Xu, L. (2025), "Adaptive Design for Contour Estimation from Computer Experiments with Quantitative and Qualitative Inputs",  SIAM/ASA Journal on Uncertainty Quantification (in press). [https://doi.org/10.48550/arXiv.2504.05498]

4. Ranjan, P. , Koley, A., Pal, S.K., and Kundu, D. (2025), "Failure Time Prediction Model for an Injection Molding System"  In Special Proceedings of the 27th Annual Conference of SSCA held at NEHU, Shillong; pp 1-11. ISBN #: 978-81-950383-8-1 [https://SSCA.org.in]

5. Pal, S.K., Koley, A., Ranjan, P., and Kundu, D. (2024), "Modeling time to failure using a temporal sequence of events", Quality Engineering, 37(3), 493–512. https://doi.org/10.1080/08982112.2024.2441367 [https://arxiv.org/abs/2412.05836] 

6. Danish, S., Ranjan, P. and Sharma, R. (2024), "Estimating Future Value of Patents Using Varying Depreciation Rate: An Application of Renewal Decision Model",  Technology Analysis and Strategy Management, 1-18, https://doi.org/10.1080/09537325.2024.2369563.

7. Kumar, A., Ranjan, P., Koley, A. and Danish, S. (2024) "A new hybrid machine learning model for predicting the renewal life of patents", PLOS One, 19(6), e0306186 [https://doi.org/10.1371/journal.pone.0306186].

8. Danish, S., Ranjan, P. and Sharma, R. (2024), "Analysis of patent mortality rate across different technology fields in India", Asian Journal of Technology Innovation, 32:1, 83-105. [https://doi.org/10.1080/19761597.2022.2163907]

9. Batra, P., Spencer, N.A. and Ranjan, P. (2023), "Isomorphism Check for Two-level Multi-Stage Factorial Designs with Randomization Restrictions via an R Package: IsoCheck", Statistics, Optimization and Information Computing, 11(4), 892-910. [https://doi.org/10.19139/soic-2310-5070-1494]

10. Ranjan, P., Resch, J. and Mandal, A. (2023), "Solving an Inverse Problem for Time Series Valued Computer Simulators via Multiple Contour Estimation" Journal of Statistical Theory and Practice, 17, 23 [https://doi.org/10.1007/s42519-022-00312-5 / arXiv:2211.0.119 / https://rdcu.be/c5cTz]

11. Danish, S., Ranjan, P. and Sharma, R. (2022), "Assessing the Impact of Patent Attributes on the Value of Discrete and Complex Innovation", International Journal of Innovation Management, 26(2), 2250016. [https://dx.doi.org/10.1142/S1363919622500165 / arXiv:2208.07222]

12. Ranjan, P. and Harshvardhan, M. (2022), "The Evolution of Dynamic Gaussian Process Model with Applications to Malaria Vaccine Coverage Prediction" in Applied Statistical Methods: ISGES 2020, Pune, India, January 2-4. Springer Proceedings in Mathematics & Statistics [Eds: Hanagal, D.D., Latpatel R.V. and Chandra, G.; arXiv:2012.11124; https://doi.org/10.1007/978-981-16-7932-2_7]

13. Danish, S., Ranjan, P. and Sharma, R. (2021), "Determinants of Patent Survival in Emerging Economies: Evidence from Residential Patents in India". Journal of Public Affairs, 21(2),e2211, .[http://dx.doi.org/10.1002/pa.2211 / arXiv:2208.05292]

14. Ranjan, P. (2020), "Statistical Modelling and Calibration of a Dynamic Computer Simulator", In Proceedings of the 22nd Annual Conference of SSCA held at Savitribai Phule Pune University, Pune; pp 85–101 [https://ssca.org.in/]

15. Danish, S., Ranjan, P. and Sharma, R. (2020), “Valuation of patents in emerging economies: A renewal model based study of Indian patent", Technology Analysis and Strategy Management, 32(4),457-473. [https://doi.org/10.1080/09537325.2019.1668552 / arXiv:2208.06157]

16. Yang, F., Lin, C.D., and Ranjan, P. (2020), "Global Fitting of the Response Surface via Estimating Multiple Contours of a Simulator" Journal of Statistical Theory and Practice,14(9),1-21  [arXiv:1902.01011] [https://doi.org/10.1007/s42519-019-0077-0]

17. Spencer, N.A., Ranjan, P., and Mendivil, F., (2019), "Isomorphism Check for 2^n Factorial Designs with Randomization Restrictions", Journal of Statistical Theory and Practice,13(60),1-24 [arXiv:1310.3574] [https://doi.org/10.1007/s42519-019-0064-5]

18. Zhang, R., Lin, C.D., and Ranjan, P. (2019), “A Sequential Design Approach for Calibrating Dynamic Computer Simulators”, SIAM/ASA Journal on Uncertainty Quantification, 7(4), 1245-1274. [arXiv:1811.00153] [https://doi.org/10.1137/18M1224544] 

19. Harshvardhan, M. and Ranjan P. (2019), "Statistical Modelling and Analysis of the Computer-Simulated Datasets" In B. Gupta, & D. Agrawal (Eds.), Handbook of Research on Cloud Computing and Big Data Applications in IoT (pp. 202-228). Hershey, PA: IGI Global. doi:10.4018/978-1-5225-8407-0.ch011 [Book Chapter / arXiv:2012.11122]

20. Bhattacharjee, N.V., Ranjan, P., Mandal, A. and Tollner, E.W. (2019), “A History Matching Approach for Calibrating Hydrological Models" , Environmental and Ecological Statistics, 26(1), 87-105. [https://arxiv.org/abs/1709.02907]

21. Mukhoti, S., and Ranjan, P., (2019), “A New Class of Discrete-time Stochastic Volatility Model with Correlated Errors”, Applied Economics, 51 (3), 259-277. [https://arxiv.org/pdf/1703.06603.pdf]

22. Zhang, R., Lin, C.D., and Ranjan, P. (2018), “Local Gaussian Process Model for Large-Scale Dynamic Computer Experiments”, Journal of Computational and Graphical Statistics, 27(4), 798-807.  [https://arxiv.org/pdf/1611.09488.pdf]

23. Ranjan, P., Thomas, M., Teismann, H. and Mukhoti, S., (2016), “Inverse problem for time-series valued computer model via scalarization”, Open Journal of Statistics, 6, 528-544.[http://dx.doi.org/10.4236/ojs.2016.63045]

24. Mukhoti, S., and Ranjan, P., (2016), “Mean-correction and Higher Order Moments for a Stochastic Volatility Model with Correlated Errors”, International Journal of Statistics and Probability, 5(4), 102-110. [https://arxiv.org/abs/1605.02418]

25. Gramacy, R., Gray, G., Le Digabel, S., Lee, H., Ranjan, P., Wells, G., and Wild, S. (2016), “Modeling an Augmented Lagrangian for Improved Blackbox Constrained Optimization”, (with discussion and rejoinder) Technometrics, 58(1), 1--29. [https://arxiv.org/pdf/1403.4890.pdf] 

26. MacDonald, K.B., Ranjan, P. and Chipman, H. (2015). GPfit: An R Package for Fitting a Gaussian Process Model to Deterministic Simulator Outputs. Journal of Statistical Software, 64(12), 1-23. [10.18637/jss.v064.i12]

27. Ranjan, P. and Spencer, N. (2014), “Space-filling Latin Hypercube Designs based on Randomization Restrictions in Factorial Experiments”, Statistics & Probability Letters, 94, 239 - 247.

28. Bingham, D., Ranjan, P., and Welch, W. (2014), “Sequential Design of Computer Experiments for Optimization, Estimating Contours, and Related Objectives”, in Statistics in Action: A Canadian Outlook. (J. F. Lawless, eds.) pp 109 – 124, Chapman and Hall/CRC, ISBN: 978-1-4822-3623-1, DOI: 10.1201/b16597-8. [Book Chapter]

29. Butler, A., Haynes, R., Humphries, T.D., and Ranjan, P. (2014), “Efficient Optimization of the Likelihood Function in Gaussian Process Modeling”, Computational Statistics and Data Analysis, 73, 40–52. [https://arxiv.org/abs/1309.6897]

30. Agarwal, R., and Ranjan, P. (2014), “A New Tree-Based Classifier for Satellite Images”, In J. Wang (Ed.), Encyclopedia of Business Analytics and Optimization (pp. 30-38). IGI Global, Hershey, PA: Business Science Reference. doi:10.4018/978-1-4666-5202-6.ch003. [Book Chapter]

31. Agarwal, R., Ranjan, P. and Chipman, H. (2014), “A new Bayesian Ensemble of Trees Ap- proach for Land Cover Classification of Satellite Imagery”, Canadian Journal of Remote Sensing, 39, 507–520. [https://doi.org/10.5589/m14-003]

32. Ranjan, P. (2013), “Comment: EI Criteria for Noisy Computer Simulators” – Discussion of ‘Quantile-Based Optimization of Noisy Computer Experiments with Tunable Precision’ by Picheny et al. (2013), Technometrics, 55(1), 24–28. DOI: 10.1080/00401706.2012.739107

33. Ranjan, P. and Spencer, N. (2013), “A Unified Approach to Factorial Designs with Randomization Restrictions” In Calcutta Statistical Association Bulletin, 65(1-4), 43–62. 

34. Franey, M., Ranjan, P. and Chipman, H., (2012), “A Short Note on Gaussian Process Modeling for Large Datasets using Graphics Processing Units” (https://arxiv.org/abs/1203.1269 [stat.CO]).

35. Chipman, H., Ranjan, P. and Wang, W. (2012), “Sequential Design for Computer Experiments with a Flexible Bayesian Additive Model”, Canadian J. Statis., 40(4), 663–678. [ https://doi.org/10.1002/cjs.11156]

36. Linkletter, C.D., Ranjan, P., Lin, C.D., Bingham, D.R., Brenneman, W.A., Lockhart, R.A. and Loughin, T.M. (2012), “Compliance Testing for Random Effects Models with Joint Acceptance Criterion”, Technometrics, 54(3), 243–255. [https://doi.org/10.1080/00401706.2012.680394]

37. Ranjan, P., Haynes, R. and Karsten, R. (2011), “A Computationally Stable Approach to Gaussian Process Interpolation of Deterministic Computer Simulation Data”, Technometrics, 53(4), 366–378. [https://doi.org/10.1198/TECH.2011.09141]

38. Ranjan, P., Lu, W., Bingham, D., Reese, S., Williams, B. J., Chou, C-C., Doss, F., Grosskopf, M. and Holloway, J. P. (2011), “Follow-up Experiment Designs for Computer Models and Physical Processes”, Journal of Statistical Theory and Practice, 5(1), 119–136.

39. Franey, M., Ranjan, P. and Chipman, H. (2011), “Branch and Bound Algorithms for Maximizing Expected Improvement Functions”, Journal of Statistical Planning and Inference, 141(1), 42 – 55.

40. Ranjan, P., Bingham, D. and Mukerjee, R. (2010), “Stars and Regular Fractional Factorial Designs with Randomization Restrictions”, Statistica Sinica, 20, 1637 – 1653.

41. Ranjan, P. (2010), “Comment on Article by Vernon et al.” – Discussion of ‘Galaxy Formation: a Bayesian Uncertainty Analysis’ by Vernon, I., Goldstein M. and Bower, R., Bayesian Analysis, 5(4), 677 – 682. [https://doi.org/10.1214/10-BA524B]

42. Ritcey, D. and Ranjan, P. (2010), “Statistical Models for the Banker’s Offer in Deal or No Deal”, The Atlantic Electronic Journal of Mathematics, 4(1), 1 – 22.

43. Stanley, C., O’Driscoll, N. and Ranjan, P. (2010), “Determining the Magnitude of True Analytical Error in Geochemical Analysis”, Geochemistry: Exploration, Environment, Analysis, 10(4), 355 – 364. 

44. Ranjan, P., Bingham, D. and Dean, A. (2009), “Existence and Construction of Randomization Defining Contrast Subspaces for Regular Factorial Designs”, The Annals of Statistics, 37(6A), 3580 – 3599.

45. Mandal, A., Ranjan, P. and Wu, C.J.F. (2009), “G-SELC: Optimization by Sequential Elimination of Level Combinations using Genetic Algorithms and Gaussian Processes”, Annals of Applied Statistics, 3(1), 398 – 421. [https://dx.doi.org/10.1214/08-AOAS199]

46. Ranjan, P., Bingham, D. and Michailidis, G. (2008), “Sequential Experiment Design for Contour Estimation from Complex Computer Codes”, Technometrics, 50, 527-541. [https://doi.org/10.1198/004017008000000541] Errata, Technometrics, 53(1), 109–110. [https://www.tandfonline.com/doi/abs/10.1198/TECH.2011.10192] 

Posters: presented at conferences

1. Design and Analysis of Experiments (DAE) 2012, Athens, Georgia [pdf]

2. Statistical Society of Canada (SSC) meetings - 2009, Vancouver [pdf]

Ph.D. Thesis: Factorial and Fractional Factorial Designs with Randomization Restrictions - A Projective Geometric Approach,  Simon Fraser University. [pdf]