Chaitanya Joshi
| Ph.D (2011 - TCD), M.Sc. (2003 - IIT-K), B.Sc. (2001 - Mumbai)
| Senior Lecturer, |
| Department of Mathematics and Statistics, |
| Univerisity of Waikato, Hamilton, New Zealand. |
| email: cjoshi@waikato.ac.nz |
| Current Research Interests: Bayesian Prior Elicitation and Robustness, Adversarial Risk Analysis, Bayesian Deep Learning, Modelling in Security and Crime Science |
My Research: I am interested in both: (i) Theoretical and methodological research in Bayesian methods as well as (ii) in modeling complex real life processes using statistical methods.
Theoretical and methodological research:
- I am interested in challenges around elicitation of subjective priors and the robustness of the Bayesian analysis to the choice of prior distributions. I've recently done some work
on developing new classes of prior distributions with
 .
- Going forward, I am hoping to work on developing framework for incorporating subjective expert priors in Bayesian deep learning.
- Along with
 and Ph.D. student Muhammad Ejaz, I have been developing Adversarial
Risk Analysis models for Auctions.
- Previous work includes developing computationally efficient methods for Bayesian inference. Along with and Ph.D. student Paul Brown,
we have developed a computationally efficient algorithm based on low discrepancy sequences which can be used in grid-based Bayesian methods such as
in collaboration with  .
Statistical Modelling:
- I am part of the newly formed NZ Institute of Security and Crime Science. I have done some work on modelling crime in collaboration with NZ Police. I am working on building Adversarial Risk Analysis (ARA) models
in collaboration with
 (ICMAT) and Jesus Rios. I am also involved in modelling and analysis of
Family violence data with  and PhD student Apriel Joliffe-Simpson.
- I am working on a project to model and predict traffic flows for Hamilton city using space-time models and deep learning with Masters student Dale Townsend.
- From time to time, I collaborate with scientists on interesting modelling problems. This includes recent work with
and PhD student Elizabeth Eliot-Hogg on the capacity of urban restored sites to support native birds. Previously, work with  group
on incorporating uncertainty using Bayesian methods. Earlier, I also worked with  (now at Univ. of Wyoming, U.S.) on problems related to modeling
species distribution. We developed a novel mathematical framework called 'Traitspace' which incorporates the various processes/factors which govern the assembly of ecological
communities via their functional traits and predicts the community assembly by using the observed trait values.
Previous work/interests:
- Efficient Bayesian inference on Stochastic Differential Equation (SDE) models, Epidemiology, Clinical trials, Demand estimation and Market research.
- From 2003 until 2007, I worked as a statistician for a number of leading corporations in the pharmaceutical and market research area.
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Current
- Sarah Hall (PhD - current)
- Julia Gasston (PhD - current)
- Apriel Joliffe-Simpson (PhD - current)
Past
- Muhammad Ejaz (PhD. 2021)
- Dale Townsend (Msc. 2021, B.Sc Hons. 2018)
- Elizabeth Eliot-Hogg (PhD. 2020)
- Lingling Yang (M.Sc. 2020)
- Paul Brown (PhD. 2018, B.Sc Hons. 2013)
- Charne Nel (B.Sc Hons. 2018)
- Clayton D'Ath (B.Sc Hons. 2017)
- Xin Li (B.Sc Hons. 2015)
- Claire Forsythe (M.Sc. 2014)
- Bayesian Implementation of the Fault Tree Analysis Chaitanya Joshi , Fabrizio Ruggeri, Simon Wilson. Wiley StatsRef: Statistical Reference Online (forthcoming)
- On approximating the shape of One-Dimensional Posterior Marginals using the Low Discrepancy Points. Chaitanya Joshi , Paul T Brown, Stephen Joe. Communications in Statistics: Theory and Methods (forthcoming)
 .
- Considerations for developing predictive models of crime and new methods for measuring their accuracy. Joshi, C., Curtis-Ham, S., D’Ath, C., Searle, D. ISPRS Int. J. Geo-Inf, 10(9), 597.
- Adversarial Risk Analysis for Auctions using Mirror Equillibrium and Bayes Nash Equillibrium. Muhammad Ejaz, Stephen Joe, Chaitanya Joshi . Decision Analysis, vol. 18 (3): 185 - 202.
- Insider Threat Modeling: an Adversarial Risk Analysis Approach. Chaitanya Joshi , Jesus Rios Aliaga, David Rios Insua. IEEE Transactions on Information Forensics and Security, Vol.16: 1131-1142.
 .
- A Novel Method of Marginalisation using Low Discrepancy Sequences for Integrated Nested Laplace Approximations. Paul T Brown, Chaitanya Joshi , Stephen Joe, Haavard Rue. Comp. Stats. & Data Anal. vol. 157. 107147
- Adversarial Risk Analysis for First-Price Sealed-Bid Auctions. Muhammad Ejaz, Chaitanya Joshi , Stephen Joe. Australia New Zealand Journal of Statistics Vol. 63, Issue 2: 357 -376.
- Predictive Validity of the DYRA and SAFVR: New Zealand Police Family Violence Risk Assessment Measures. Apriel Joliffe-Simpson, Chaitanya Joshi , Devon Polaschek. Criminal Justice and Behaviour. Vol. 48, Issue 10: 1487 -1508.
| Papers under review/revision |
- Habitat provision is more important than predation in driving native bird communities in restored urban forests. Elizabeth Elliot Noe, John Innes, Andrew Barnes, Chaitanya Joshi , Bruce Clarkson.
- Adversarial Risk Analysis for auctions using non-strategic play and level-k thinking: A general case of n bidders with regret. Muhammad Ejaz, Chaitanya Joshi ,Stephen Joe.
- Looking for the structure in structured professional judgement: Risk factors for family violence recurrence recorded by a multi-agency family violence response. Jolliffe Simpson, A. D., Joshi, C. & Polaschek, D. L. L.
- Methods for eliciting informative prior distributions. Falconer, J.R., Frank, E., Polaschek, D. L. L. and Joshi, C.
- A predictive class of prior distributions that accounts for uncertainty in the data Chaitanya Joshi , Fabrizio Ruggeri
 .
- Urban forest restoration provides habitat for invasive mammals which decrease regeneration success. Elizabeth Elliot Noe, John Innes, Chaitanya Joshi , Kiri Joy Wallace, Bruce Clarkson.
- Predictive ability of New Zealand Police’s family violence risk assessment instruments: Practical implications for frontline policing. Jolliffe Simpson, A., Joshi, C. , Polaschek, D., Police Science, 5(2), 24 – 25 (2020)
- Perpetrators of family harm already serving correctional sentences: Risk profiles and episode characteristics.Jolliffe Simpson, A., Moore, D., Joshi, C., Polaschek, D., Psychology Aotearoa, 11(2), 138
- Generating species assemblages for ecological restoration: a new method that simultaneously converges on average trait values and maximizes functional diversity. Daniel Laughlin, Lois Chalmandrier, Chaitanya Joshi , M. Renton, J.Funk, J. Dwyer. Methods in Ecology and Evolution , Vol 9, 7:1764-71
- Bayesian Robustness for Fault Tree Analysis. Chaitanya Joshi , Fabrizio Ruggeri, Simon P. Wilson.IEEE Transactions on Reliability, 67(1):170 - 183.
- The carbon balance of temperate grasslands part I: The impact of increased species diversity. Rutledge S, Wall AM, Mudge PL, Troughton B, Campbell DI, Pronger J, Joshi C, Schipper LA. Agriculture, Ecosystems and Environment 239:132-142
- The carbon balance of temperate grasslands part II: The impact of pasture renewal via direct drilling. Rutledge S, Wall AM, Mudge PL, Troughton B, Campbell DI, Pronger J, Joshi C, Schipper LA. Agriculture, Ecosystems and Environment 239:310-323
- Isotope tracing of long-term cadmium fluxes in an agricultural soil. Salmanzadeh Mahdiyeh, Hartland Adam, Stirling Claudine, Balks Megan, Schipper Louis, Joshi Chaitanya, George Ejin.(submitted)
- Improving grid based Bayesian inference. Joshi Chaitanya, Brown Paul T., Joe Stephen. MCQMC Conference 2016, Stanford University
- Spatio-temporal modelling of crime using low discrepancy sequences. Brown Paul T., Joshi Chaitanya, Joe Stephen, N. McCarter. International Workshop on Statistical Modeling 2016, Rennes, France.
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 : A
Predictive Model for Trait Based Community Assembly of Plant Species. R package version 1.0. Joshi Chaitanya, Li Xin, Laughlin Daniel C.,
- Low discrepancy sequences for faster Bayesian inference. Joshi Chaitanya, Paul T. Brown, Stephen Joe, BISP 2015, talk.
- Inferring user actions from provenance logs. Li Xin, Joshi Chaitanya, Tan Y.S, Ko R.K.L, (proceedings of the IEEE TrustCom 2015).
- Theoretical consequences of trait-based environmental filtering for the breadth and shape of the niche: New testable hypotheses generated by the Traitspace model. Laughlin Daniel C., Joshi Chaitanya, Ecological Modelling, 307, pp.10-21
- Quantifying multimodal trait distributions improves trait-based predictions of species abundances and functional diversity. Laughlin Daniel C., Joshi Chaitanya, Richardson Sarah J., Duane A. Peltzer, Mason Norman W.H., David A. Wardle, Journal of Vegetation Science (2014)
- Integrated nested Laplace approximation using low discrepancy sequences. Joshi Chaitanya, Paul T. Brown, Stephen Joe, ISBA World meeting 2014, poster (2014).
- Inferential tests and modelling of functional trait convergence along environmental gradients. Chaitanya Joshi, Paul T. Brown, Daniel C. Laughlin, Proceedings of the World Statistics Congress 2013, in print (2013)
- Implementing ecological compensation - stakeholder perspectives and a way forward. Marie A. Brown, Bruce D. Clarkson, Barry J. Barton, Chaitanya Joshi, Journal of the Royal Society of New Zealand (2013)
- Ecological compensation: an evaluation of regulatory compliance in New Zealand. Marie A. Brown, Bruce D. Clarkson, Barry J. Barton, Chaitanya Joshi, Impact Assessment and Project Appraisal, in print (2013)
- A predictive model of community assembly that incorporates intraspecific trait variation. Daniel C. Laughlin, Chaitanya Joshi , Peter M. Van Bodegom, Zachary A. Bastow, Peter Z. Fule. Ecology Letters, 15, p.1291-1299.
- Modeling trait based ecological community assembly. Chaitanya Joshi , Daniel C. Laughlin, Peter M. Van Bodegom, Zachary A. Bastow, Peter Z. Fule. Proceedings of the 27th International Workshop on Statistical Modelling, Volume I, p.177-178.
- A new solution to a perennial problem: predicting species abundances using intraspecific trait variation - oral presentation (2012)
Laughlin, Daniel C, Joshi, Chaitanya , Ecological Society of Australia - 2012 Annual Conference.
- On Computationally Efficient Estimation of the Variance of the Randomised Quasi Monte Carlo Estimate - oral presentation (2012)
Joshi, Chaitanya. 10th International Conference on Monte Carlo and Quasi Monte Carlo Methods in Scientific Computing, UNSW, Sydney, Australia
- Adaptive sampling strategy for assessment of avian biodiversity. Gore, A. P., Paranjpe, S. A., Joshi, C. , Pramod, P., Daniels, R., Gerow, K. International Journal of Statistical Sciences (Special Issue), p.75-89.
- On efficient estimation of the variance of the Randomised Quasi Monte Carlo estimate. Haslett, J., Joshi, C. , Geveli, R. V. TCD-Statistics-11-08. Trinity College, Dublin, 2011. p.1-13.
- Review of 'An explicit link between Gaussian fields and Gaussian Markov random fields: The SPDE approach'. Haslett, J., Joshi, C. , Garreta, V. Journal of the Royal Statistical Society: Series B (Statistical Methodology). v73, no4, 2011. p.423-498.
- Grid based Bayesian inference for Stochastic Differential Equation models. Joshi, C. , Wilson, S. TCD-Statistics-11-07. Trinity College, Dublin, 2011. p.1-34.
- Modeling dynamic force using Stochastic differential equations. Joshi, C. , Wilson, S. TCD-Statistics-11-06. Trinity College, Dublin, 2011. p.1-11.
- A New Method to Implement Bayesian Inference on Stochastic Differential Equation Models (Ph.D. thesis). Chaitanya Joshi . Trinity College Dublin, University of Dublin, Ireland, 2011. p.1-143.
- GaMBA: For fast Bayesian Inference on Stochastic Differential Equation Models - oral presentation (2011)
Joshi, Chaitanya and Wilson Simon P. Workshop on Bayesian Inference for Latent Gaussian Models with Applications. February 2-5, 2011. University of Zurich, Switzerland.
- Stochastic Differential Equation Models for Dynamic Force - poster (2010)
Joshi C., Wilson S.P., O'Brien E., and Taheri A. - ISBA 10/Valencia 9 conference held at Benidorm,Spain.
- A New Method to Approximate Bayesian Inference on Diffusion Processes - oral presentation (2009)
Joshi C., and Wilson S.P. - 6th Bayesian Inference for Stochastic Processes (BISP-6) conference held in Bressanone, Italy.
- Abatacept Reduces Fatigue and Pain Severity and Sleep Problems through 2 years in Rheumatoid Arthritis Patients in the AIM and ATTAIN Trials. Dougados, M., Russell, A., Li, T., Sherrer, Y., Becker, J., Gandhi, M., Joshi, C. , Westhovens, R.Ann Rheum Dis. v., BMJ, p.429-429
- Introduction to Clinical Trials and the role of Bio-statistician.- invited talk (2007)
Joshi Chaitanya - Symposium on Recent Advances in Mathematical Sciences held at Indian Institute of Technology Kanpur, India.
Current
- Sarah Hall (PhD - current)
- Julia Falconer (PhD - current)
- Apriel Simpson (PhD - current)
Past
- Muhammad Ejaz (PhD. 2021)
- Dale Townsend (Msc. 2021, B.Sc Hons. 2018)
- Elizabeth Eliot-Hogg (PhD. 2021)
- Linlin Yang (Msc. 2020)
- Paul Brown (PhD. 2018, B.Sc Hons. 2013)
- Charne Nel (B.Sc Hons. 2018)
- Clayton D'Ath (B.Sc Hons. 2017)
- Xin Li (B.Sc Hons. 2015)
- Claire Forsythe (M.Sc. 2014)
COURSES I teach/have taught:
- STATS531 Multivariate Analysis
- STATS522 Statistical Inference
- STATS521 Computational Statistics
- STATS326 Computational Bayesian Statistics
- STATS322 Probability and Mathematical Statistics
- STATS222 Principles of Probability and Statistical Inference
- STATS221 Statistical Data Analysis
- STATS111 Statistics for Science
- STATS160 Management Statistics
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