Johann Gagnon-Bartsch, Yotam Shem-Tov.

Source: The Annals of Applied Statistics, Volume 13, Number 3, 1464--1483.

Abstract:
The gold standard for identifying causal relationships is a randomized controlled experiment. In many applications in the social sciences and medicine, the researcher does not control the assignment mechanism and instead may rely upon natural experiments or matching methods as a substitute to experimental randomization. The standard testable implication of random assignment is covariate balance between the treated and control units. Covariate balance is commonly used to validate the claim of as good as random assignment. We propose a new nonparametric test of covariate balance. Our Classification Permutation Test (CPT) is based on a combination of classification methods (e.g., random forests) with Fisherian permutation inference. We revisit four real data examples and present Monte Carlo power simulations to demonstrate the applicability of the CPT relative to other nonparametric tests of equality of multivariate distributions.

Piotr Kokoszka, Neda Mohammadi Jouzdani.

Source: Bernoulli, Volume 26, Number 3, 2383--2399.

Abstract:
This paper is concerned with frequency domain theory for functional time series, which are temporally dependent sequences of functions in a Hilbert space. We consider a variance decomposition, which is more suitable for such a data structure than the variance decomposition based on the Karhunen–Loéve expansion. The decomposition we study uses eigenvalues of spectral density operators, which are functional analogs of the spectral density of a stationary scalar time series. We propose estimators of the variance components and derive convergence rates for their mean square error as well as their asymptotic normality. The latter is derived from a frequency domain invariance principle for the estimators of the spectral density operators. This principle is established for a broad class of linear time series models. It is a main contribution of the paper.

Ulrike Mayer, Henryk Zähle, Zhou Zhou.

Source: Bernoulli, Volume 26, Number 3, 1891--1911.

Abstract:
We derive a functional weak limit theorem for a local empirical process of a wide class of piece-wise locally stationary (PLS) time series. The latter result is applied to derive the asymptotics of weighted empirical quantiles and weighted V-statistics of non-stationary time series. The class of admissible underlying time series is illustrated by means of PLS linear processes and PLS ARCH processes.

Yating Liu, Gilles Pagès.

Source: Bernoulli, Volume 26, Number 2, 1171--1204.

Abstract:
We establish conditions to characterize probability measures by their $L^{p}$-quantization error functions in both $mathbb{R}^{d}$ and Hilbert settings. This characterization is two-fold: static (identity of two distributions) and dynamic (convergence for the $L^{p}$-Wasserstein distance). We first propose a criterion on the quantization level $N$, valid for any norm on $mathbb{R}^{d}$ and any order $p$ based on a geometrical approach involving the Voronoï diagram. Then, we prove that in the $L^{2}$-case on a (separable) Hilbert space, the condition on the level $N$ can be reduced to $N=2$, which is optimal. More quantization based characterization cases in dimension 1 and a discussion of the completeness of a distance defined by the quantization error function can be found at the end of this paper.

Peggy Cénac, Basile de Loynes, Yoann Offret, Arnaud Rousselle.

Source: Bernoulli, Volume 26, Number 2, 858--892.

Abstract:
The recurrence and transience of persistent random walks built from variable length Markov chains are investigated. It turns out that these stochastic processes can be seen as Lévy walks for which the persistence times depend on some internal Markov chain: they admit Markov random walk skeletons. A recurrence versus transience dichotomy is highlighted. Assuming the positive recurrence of the driving chain, a sufficient Fourier criterion for the recurrence, close to the usual Chung–Fuchs one, is given and a series criterion is derived. The key tool is the Nagaev–Guivarc’h method. Finally, we focus on particular two-dimensional persistent random walks, including directionally reinforced random walks, for which necessary and sufficient Fourier and series criteria are obtained. Inspired by ( Adv. Math. 208 (2007) 680–698), we produce a genuine counterexample to the conjecture of ( Adv. Math. 117 (1996) 239–252). As for the one-dimensional case studied in ( J. Theoret. Probab. 31 (2018) 232–243), it is easier for a persistent random walk than its skeleton to be recurrent. However, such examples are much more difficult to exhibit in the higher dimensional context. These results are based on a surprisingly novel – to our knowledge – upper bound for the Lévy concentration function associated with symmetric distributions.

Jing Lei.

Source: Bernoulli, Volume 26, Number 1, 767--798.

Abstract:
We provide upper bounds of the expected Wasserstein distance between a probability measure and its empirical version, generalizing recent results for finite dimensional Euclidean spaces and bounded functional spaces. Such a generalization can cover Euclidean spaces with large dimensionality, with the optimal dependence on the dimensionality. Our method also covers the important case of Gaussian processes in separable Hilbert spaces, with rate-optimal upper bounds for functional data distributions whose coordinates decay geometrically or polynomially. Moreover, our bounds of the expected value can be combined with mean-concentration results to yield improved exponential tail probability bounds for the Wasserstein error of empirical measures under Bernstein-type or log Sobolev-type conditions.

Saint Paul schools are in the market for a vendor to provide background checks, while the Education Technology Joint Powers Authority is seeking media repositories. A Texas district wants quotes on technology for new campuses.

The post Calif. Ed-Tech Consortium Seeks Media Repository Solutions; Saint Paul District Needs Background Check Services appeared first on Market Brief.

Delta said it is making the move to protect employees amid the coronavirus pandemic, but planes have been flying near empty

Claudia Kirch, Matthew C. Edwards, Alexander Meier, Renate Meyer.

Source: Bayesian Analysis, Volume 14, Number 4, 1037--1073.

Abstract:
Nonparametric Bayesian inference has seen a rapid growth over the last decade but only few nonparametric Bayesian approaches to time series analysis have been developed. Most existing approaches use Whittle’s likelihood for Bayesian modelling of the spectral density as the main nonparametric characteristic of stationary time series. It is known that the loss of efficiency using Whittle’s likelihood can be substantial. On the other hand, parametric methods are more powerful than nonparametric methods if the observed time series is close to the considered model class but fail if the model is misspecified. Therefore, we suggest a nonparametric correction of a parametric likelihood that takes advantage of the efficiency of parametric models while mitigating sensitivities through a nonparametric amendment. We use a nonparametric Bernstein polynomial prior on the spectral density with weights induced by a Dirichlet process and prove posterior consistency for Gaussian stationary time series. Bayesian posterior computations are implemented via an MH-within-Gibbs sampler and the performance of the nonparametrically corrected likelihood for Gaussian time series is illustrated in a simulation study and in three astronomy applications, including estimating the spectral density of gravitational wave data from the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO).

Muteb Alharthi, Theodore Kypraios, Philip D. O’Neill.

Source: Bayesian Analysis, Volume 14, Number 3, 927--956.

Abstract:
We consider the problem of model choice for stochastic epidemic models given partial observation of a disease outbreak through time. Our main focus is on the use of Bayes factors. Although Bayes factors have appeared in the epidemic modelling literature before, they can be hard to compute and little attention has been given to fundamental questions concerning their utility. In this paper we derive analytic expressions for Bayes factors given complete observation through time, which suggest practical guidelines for model choice problems. We adapt the power posterior method for computing Bayes factors so as to account for missing data and apply this approach to partially observed epidemics. For comparison, we also explore the use of a deviance information criterion for missing data scenarios. The methods are illustrated via examples involving both simulated and real data.

Pantelis Samartsidis, Shaun R. Seaman, Anne M. Presanis, Matthew Hickman, Daniela De Angelis.

Source: Statistical Science, Volume 34, Number 3, 486--503.

Abstract:
Researchers are often challenged with assessing the impact of an intervention on an outcome of interest in situations where the intervention is nonrandomised, the intervention is only applied to one or few units, the intervention is binary, and outcome measurements are available at multiple time points. In this paper, we review existing methods for causal inference in these situations. We detail the assumptions underlying each method, emphasize connections between the different approaches and provide guidelines regarding their practical implementation. Several open problems are identified thus highlighting the need for future research.

Yuan Ke, Stanislav Minsker, Zhao Ren, Qiang Sun, Wen-Xin Zhou.

Source: Statistical Science, Volume 34, Number 3, 454--471.

Abstract:
We provide a survey of recent results on covariance estimation for heavy-tailed distributions. By unifying ideas scattered in the literature, we propose user-friendly methods that facilitate practical implementation. Specifically, we introduce elementwise and spectrumwise truncation operators, as well as their $M$-estimator counterparts, to robustify the sample covariance matrix. Different from the classical notion of robustness that is characterized by the breakdown property, we focus on the tail robustness which is evidenced by the connection between nonasymptotic deviation and confidence level. The key insight is that estimators should adapt to the sample size, dimensionality and noise level to achieve optimal tradeoff between bias and robustness. Furthermore, to facilitate practical implementation, we propose data-driven procedures that automatically calibrate the tuning parameters. We demonstrate their applications to a series of structured models in high dimensions, including the bandable and low-rank covariance matrices and sparse precision matrices. Numerical studies lend strong support to the proposed methods.

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.

Steven Poser
Jun 1, 2003; 23:4420-4427
Cellular

KM Harris
Aug 1, 1989; 9:2982-2997
Articles

Italian translation of Press Release about BIS General Manager Agustín Carstens giving a speech on "Money in the digital age: what role for central banks?" (6 February 2018)

Customer service doesn't have to suffer while your company goes through a difficult transition. In fact, 78 percent of consumers said they stopped doing business with a company because of poor customer service. Now is the time to show your most valuable buyers how you'll keep them informed, updated and respected throughout this crisis by adapting your practices to the moment.

02020-02-07: Badain Jaran Desert

Speech by Mr Agustín Carstens, General Manager of the BIS, at the Fourteenth ASBA-BCBS-FSI High-level Meeting on Global and Regional Supervisory Priorities, Lima, 1 October 2019.

In the face of changing weather driven by climate change and the increasing demand for food, Conservation Agriculture (CA) aims to achieve sustainable and profitable agriculture and improve farmers’ livelihoods. Here are five things you need to know. 1. CA observes three main principles that you should remember Direct seeding involves growing crops without mechanical seedbed preparation and with minimal soil disturbance [...]

Ecosystem services make human life possible by, for example, providing nutritious food and clean water, regulating disease and climate, supporting the pollination of crops and soil formation, and providing recreational, cultural and spiritual benefits. In 2014, the value of ecosystem services was estimated at a staggering US$ 125 trillion.  Ecosystem services, provided by biodiversity, are fundamental to food production and [...]

Radio culture is gaining more and more ground as millions of listeners take to audio podcasts as a convenient and accessible way to learn new information.  Which is why FAO is stepping up into the medium to bring you insights into some of the issues concerning food and agriculture worldwide. Here are the first seven audio offerings of FAO’s new podcast [...]

How the beloved figure has become a lightning rod in a heated environmental debate

As monarchs leave their winter hideaways, conservationists are seeking assistance in studying their migration routes

"Occupy White Walls" allows players to design their own art galleries—and explore others' out-of-the-box creations

The carvings, which depict animals including camels, leopards, cows and mules, may date back to 3000 B.C.

The Chicago White Sox were heavy favorites going into the 1919 World Series. But they were defeated by the Cincinnati Reds - and it soon became clear that the game was rigged

The graphic designer is receiving a Lifetime Achievement Award from Cooper Hewitt for her recognizable computer icons, typefaces and graphics

The pandemic has put psychological theories of politics to a very interesting test.

A young boy is recovering in hospital after being hit by a car in Montreal's LaSalle borough Friday afternoon, police say.

Overcoming scorching heat and little rain, experimental vineyards teach winemakers to cope with climate change

Vowing to return next summer, this year's Little League World Series was cancelled due to the coronavirus pandemic. All seven World Series tournaments and their respective regional qualifying events are off this summer.

Winnipeg will soon test "small cell" technology to improve cellular reception in parts of Winnipeg, ahead of a possible future transition to 5G service. 

Google soon will require all advertisers to prove their legitimacy, regardless of the advertising content. All advertisers will have to verify their identity, submit personal IDs and business verification documents, said John Canfield, Google's director of product management for ads integrity. Google began requiring political advertisers to verify their identity in the runup to the 2018 elections.

Global real residential property prices rose 1.4% year/year in aggregate in Q3 2019, reflecting subdued developments both in advanced (+ 1.5%) and emerging market economies (+ 1.3%).

The formative moment for a new generation.

The Canadian three-time world champion figure skater displayed his four-wheeler driving skills as part of the Americares Blades for the Brave fundraiser for front-line workers.

The World pairs champion and Olympic gold medallist played the piano during a special hosted by fellow Canadian figure skater Kaitlyn Weaver, to raise funds for the United Nation's COVID-19 Solidarity Response Fund.

The following is a guest post from Music Reference Specialist James Wintle. Let me begin with a personal anecdote. My parents are or were both musicians – my father was a composer – and so my appreciation for classical music was probably equal parts nature and nurture. So, when I entered graduate school as a […]

Pence says lack of religious services has been 'burden'  WSET