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A Conversation with Dick Dudley

Vladimir Koltchinskii, Richard Nickl, Philippe Rigollet.

Source: Statistical Science, Volume 34, Number 1, 169--175.

Abstract:
Richard Mansfield Dudley (Dick Dudley) was born in 1938. He received the A.B. from Harvard in 1952 and the Ph.D. from Princeton in 1962 (under the supervision of Gilbert Hunt and Edward Nelson). Following an appointment at UC Berkeley as an assistant professor, he joined the Department of Mathematics at MIT in 1967. Dick Dudley has made fundamental contributions to the theory of Gaussian processes and Probability in Banach Spaces. Among his major achievements is the development of a general framework for empirical processes theory, in particular, for uniform central limit theorems. These results have had and continue having tremendous impact in contemporary statistics and in mathematical foundations of machine learning. A more extensive biographical sketch is contained in the preface to the Selected works of R. M. Dudley (editors: E. Giné, V. Koltchinskii and R. Norvaisa) published in 2010. This conversation took place (mostly, via email) in the fall of 2017.




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Generalized Multiple Importance Sampling

Víctor Elvira, Luca Martino, David Luengo, Mónica F. Bugallo.

Source: Statistical Science, Volume 34, Number 1, 129--155.

Abstract:
Importance sampling (IS) methods are broadly used to approximate posterior distributions or their moments. In the standard IS approach, samples are drawn from a single proposal distribution and weighted adequately. However, since the performance in IS depends on the mismatch between the targeted and the proposal distributions, several proposal densities are often employed for the generation of samples. Under this multiple importance sampling (MIS) scenario, extensive literature has addressed the selection and adaptation of the proposal distributions, interpreting the sampling and weighting steps in different ways. In this paper, we establish a novel general framework with sampling and weighting procedures when more than one proposal is available. The new framework encompasses most relevant MIS schemes in the literature, and novel valid schemes appear naturally. All the MIS schemes are compared and ranked in terms of the variance of the associated estimators. Finally, we provide illustrative examples revealing that, even with a good choice of the proposal densities, a careful interpretation of the sampling and weighting procedures can make a significant difference in the performance of the method.




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Gaussian Integrals and Rice Series in Crossing Distributions—to Compute the Distribution of Maxima and Other Features of Gaussian Processes

Georg Lindgren.

Source: Statistical Science, Volume 34, Number 1, 100--128.

Abstract:
We describe and compare how methods based on the classical Rice’s formula for the expected number, and higher moments, of level crossings by a Gaussian process stand up to contemporary numerical methods to accurately deal with crossing related characteristics of the sample paths. We illustrate the relative merits in accuracy and computing time of the Rice moment methods and the exact numerical method, developed since the late 1990s, on three groups of distribution problems, the maximum over a finite interval and the waiting time to first crossing, the length of excursions over a level, and the joint period/amplitude of oscillations. We also treat the notoriously difficult problem of dependence between successive zero crossing distances. The exact solution has been known since at least 2000, but it has remained largely unnoticed outside the ocean science community. Extensive simulation studies illustrate the accuracy of the numerical methods. As a historical introduction an attempt is made to illustrate the relation between Rice’s original formulation and arguments and the exact numerical methods.




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Rejoinder: Response to Discussions and a Look Ahead

Vincent Dorie, Jennifer Hill, Uri Shalit, Marc Scott, Dan Cervone.

Source: Statistical Science, Volume 34, Number 1, 94--99.

Abstract:
Response to discussion of Dorie (2017), in which the authors of that piece express their gratitude to the discussants, rebut some specific criticisms, and argue that the limitations of the 2016 Atlantic Causal Inference Competition represent an exciting opportunity for future competitions in a similar mold.




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Comment: Contributions of Model Features to BART Causal Inference Performance Using ACIC 2016 Competition Data

Nicole Bohme Carnegie.

Source: Statistical Science, Volume 34, Number 1, 90--93.

Abstract:
With a thorough exposition of the methods and results of the 2016 Atlantic Causal Inference Competition, Dorie et al. have set a new standard for reproducibility and comparability of evaluations of causal inference methods. In particular, the open-source R package aciccomp2016, which permits reproduction of all datasets used in the competition, will be an invaluable resource for evaluation of future methodological developments. Building upon results from Dorie et al., we examine whether a set of potential modifications to Bayesian Additive Regression Trees (BART)—multiple chains in model fitting, using the propensity score as a covariate, targeted maximum likelihood estimation (TMLE), and computing symmetric confidence intervals—have a stronger impact on bias, RMSE, and confidence interval coverage in combination than they do alone. We find that bias in the estimate of SATT is minimal, regardless of the BART formulation. For purposes of CI coverage, however, all proposed modifications are beneficial—alone and in combination—but use of TMLE is least beneficial for coverage and results in considerably wider confidence intervals.




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Comment: Causal Inference Competitions: Where Should We Aim?

Ehud Karavani, Tal El-Hay, Yishai Shimoni, Chen Yanover.

Source: Statistical Science, Volume 34, Number 1, 86--89.

Abstract:
Data competitions proved to be highly beneficial to the field of machine learning, and thus expected to provide similar advantages in the field of causal inference. As participants in the 2016 and 2017 Atlantic Causal Inference Conference (ACIC) data competitions and co-organizers of the 2018 competition, we discuss the strengths of simulation-based competitions and suggest potential extensions to address their limitations. These suggested augmentations aim at making the data generating processes more realistic and gradually increase in complexity, allowing thorough investigations of algorithms’ performance. We further outline a community-wide competition framework to evaluate an end-to-end causal inference pipeline, beginning with a causal question and a database, and ending with causal estimates.




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Comment on “Automated Versus Do-It-Yourself Methods for Causal Inference: Lessons Learned from a Data Analysis Competition”

Susan Gruber, Mark J. van der Laan.

Source: Statistical Science, Volume 34, Number 1, 82--85.

Abstract:
Dorie and co-authors (DHSSC) are to be congratulated for initiating the ACIC Data Challenge. Their project engaged the community and accelerated research by providing a level playing field for comparing the performance of a priori specified algorithms. DHSSC identified themes concerning characteristics of the DGP, properties of the estimators, and inference. We discuss these themes in the context of targeted learning.




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Matching Methods for Causal Inference: A Review and a Look Forward

Elizabeth A. Stuart

Source: Statist. Sci., Volume 25, Number 1, 1--21.

Abstract:
When estimating causal effects using observational data, it is desirable to replicate a randomized experiment as closely as possible by obtaining treated and control groups with similar covariate distributions. This goal can often be achieved by choosing well-matched samples of the original treated and control groups, thereby reducing bias due to the covariates. Since the 1970s, work on matching methods has examined how to best choose treated and control subjects for comparison. Matching methods are gaining popularity in fields such as economics, epidemiology, medicine and political science. However, until now the literature and related advice has been scattered across disciplines. Researchers who are interested in using matching methods—or developing methods related to matching—do not have a single place to turn to learn about past and current research. This paper provides a structure for thinking about matching methods and guidance on their use, coalescing the existing research (both old and new) and providing a summary of where the literature on matching methods is now and where it should be headed.




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Heteromodal Cortical Areas Encode Sensory-Motor Features of Word Meaning

The capacity to process information in conceptual form is a fundamental aspect of human cognition, yet little is known about how this type of information is encoded in the brain. Although the role of sensory and motor cortical areas has been a focus of recent debate, neuroimaging studies of concept representation consistently implicate a network of heteromodal areas that seem to support concept retrieval in general rather than knowledge related to any particular sensory-motor content. We used predictive machine learning on fMRI data to investigate the hypothesis that cortical areas in this "general semantic network" (GSN) encode multimodal information derived from basic sensory-motor processes, possibly functioning as convergence–divergence zones for distributed concept representation. An encoding model based on five conceptual attributes directly related to sensory-motor experience (sound, color, shape, manipulability, and visual motion) was used to predict brain activation patterns associated with individual lexical concepts in a semantic decision task. When the analysis was restricted to voxels in the GSN, the model was able to identify the activation patterns corresponding to individual concrete concepts significantly above chance. In contrast, a model based on five perceptual attributes of the word form performed at chance level. This pattern was reversed when the analysis was restricted to areas involved in the perceptual analysis of written word forms. These results indicate that heteromodal areas involved in semantic processing encode information about the relative importance of different sensory-motor attributes of concepts, possibly by storing particular combinations of sensory and motor features.

SIGNIFICANCE STATEMENT The present study used a predictive encoding model of word semantics to decode conceptual information from neural activity in heteromodal cortical areas. The model is based on five sensory-motor attributes of word meaning (color, shape, sound, visual motion, and manipulability) and encodes the relative importance of each attribute to the meaning of a word. This is the first demonstration that heteromodal areas involved in semantic processing can discriminate between different concepts based on sensory-motor information alone. This finding indicates that the brain represents concepts as multimodal combinations of sensory and motor representations.




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Smart women don't smoke / Biman Mullick.

London (33 Stillness Road, London SE23 1NG) : Cleanair, Campaign for a Smoke-free Environment, [1989?]




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Angel over the city.

1990.




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We thank you for not smoking / design : Biman Mullick.

London (33 Stillness Rd, London, SE23 1NG) : Cleanair, Campaign for a Smoke-free Environment, [198-?]




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'Smoke gets in your eyes' / Biman Mullick.

London (33 Stllness Rd, London, SE23 1NG) : Cleanair, Campaign for a Smoke-free Environment, [198-?]




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'Smoking is slow-motion suicide' / Biman Mullick.

London (33 Stillness Rd, London, SE23 ING) : Cleanair, Campaign for a Smoke-free Environment, [198-?]




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Smoking affects us all. / Biman Mullick.

London (33 Stillness Rd, London, SE23 1NG) : Cleanair, Campaign for a Smoke-free Environment, [198-?]




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If you must smoke don't exhale / design : Biman Mullick.

London (33 Stillness Rd, London, SE23 1NG) : Cleanair, Campaign for a Smoke-free Environment, [198-?]




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Passive smoking kills / Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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Be nice to yourself and others / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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Pollution / Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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Cleanair not smoke / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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No smoking no hate / Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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No smoking zone / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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Heart burn. / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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Smoking is anti-social / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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Tapadh leibh airson nach do smoc sibh / design : Biman Mullick.

London (33 Stillness Rd, SE23 1NG) : Cleanair, Campaign for a Smoke-free Environment, [198-?]




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No smoking is the norm / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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We thank you for not smoking / design : Biman Mullick.

London (33 Stillness Rd, London, SE23 1NG) : Cleanair, Campaign for a Smoke-free Environment, [198-?]




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No smoking zone / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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We thank you for not smoking / Biman Mullick.

London : Cleanair, [1988?]




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If you must smoke don't exhale / Biman Mullick.

London : Cleanair, [1988?]




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Muchas gracias por no fumar / Biman Mullick.

London : Cleanair, [1988?]




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Merci de ne pas fumer / Biman Mullick.

London : Cleanair, [1988?]




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Elle est classe, elle ne fume pas / Biman Mullick.

London (33 Stillness Road, London SE23 1NG) : Cleanair, [1989?]




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We thank you for not smoking / design : Biman Mullick.

London (33 Stillness Rd, London, SE23 1NG) : Cleanair, Campaign for a Smoke-free Environment, [198-?]




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No smoking is the norm / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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Be nice to yourself and others / design : Biman Mullick.

London : Cleanair, Smoke-free Environment (33 Stillness Rd, London, SE23 1NG), [198-?]




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दिल की जलन। = Heart burn. / design : Biman Mullick.

London : Cleanair (33 Stillness Rd, London, SE23 1NG), [1989?]




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Dila jalana = Heart burn. / design : Biman Mullick.

London : Cleanair (33 Stillness Rd, London, SE23 1NG), [198-?]




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Hārtabarna = Heart burn. / design : Biman Mullick.

London : Cleanair (33 Stillness Rd, London, SE23 1NG), [198-?]




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Ha gubin wadnahaaga! = Heart burn. / design : Biman Mullick.

London : Cleanair (33 Stillness Rd, London, SE23 1NG), [198-?]




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Hārta jbalē = Heart burn. / design : Biman Mullick.

London : Cleanair (33 Stillness Rd, London, SE23 1NG), [198-?]




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Heat burn. / design : Biman Mullick.

London : Cleanair (33 Stillness Rd, London, SE23 1NG), [198-?]




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Gracias por no fumar / deseño : Biman Mullick.

[London] : Cleanair, Campaña para un Medio Ambiente Libre de Humo, [198-?]




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No fumar es la moda / deseño : Biman Mullick.

[London] : Cleanair, Campaña para un Medio Ambiente Libre de Humo, [198-?]




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Muchas gracias por no fumar / Biman Mullick.

[London] : Cleanair, [1989?]




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Tapadh leibh airson nach do smoc sibh / design: Biman Mullick.

London (33 Stillness Road London SE23 1NG) : Cleanair Campaign for a Smoke-free Environment, [198-?]




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Zona de no fumar / deseño : Biman Mullick.

London : Cleanair Campaña para un Medio Ambiente Libre de Humo, [198-?]




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Elle est classe, elle ne fume pas / Biman Mullick.

London (33 Stillness Rd, SE23 1NG) : Cleanair, [198-?]




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Cleanair posters to create a smoke-free environment / designed by Biman Mullick ; published by Cleanair.

London (33 Stillness Road, London SE23 ING) : Cleanair, [198-?]




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Smoking is bad for your image / design : Biman Mullick.

[London?], [199-?]