Shape Constraints from Parametric and Non-parametric Models

Shape Constraints from Parametric and Non-parametric Models PDF Author: Ari David Gross
Publisher:
ISBN:
Category :
Languages : en
Pages : 444

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Shape Constraints from Parametric and Non-parametric Models

Shape Constraints from Parametric and Non-parametric Models PDF Author: Ari David Gross
Publisher:
ISBN:
Category :
Languages : en
Pages : 444

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Book Description


Nonparametric Estimation under Shape Constraints

Nonparametric Estimation under Shape Constraints PDF Author: Piet Groeneboom
Publisher: Cambridge University Press
ISBN: 0521864011
Category : Business & Economics
Languages : en
Pages : 429

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Book Description
This book introduces basic concepts of shape constrained inference and guides the reader to current developments in the subject.

Nonparametric Estimation Under Shape Constraints

Nonparametric Estimation Under Shape Constraints PDF Author: P. Groeneboom
Publisher:
ISBN: 9781139020893
Category : Estimation theory
Languages : en
Pages :

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Parametric and Nonparametric Inference for Statistical Dynamic Shape Analysis with Applications

Parametric and Nonparametric Inference for Statistical Dynamic Shape Analysis with Applications PDF Author: Chiara Brombin
Publisher: Springer
ISBN: 9783319263106
Category : Mathematics
Languages : en
Pages : 115

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Book Description
This book considers specific inferential issues arising from the analysis of dynamic shapes with the attempt to solve the problems at hand using probability models and nonparametric tests. The models are simple to understand and interpret and provide a useful tool to describe the global dynamics of the landmark configurations. However, because of the non-Euclidean nature of shape spaces, distributions in shape spaces are not straightforward to obtain. The book explores the use of the Gaussian distribution in the configuration space, with similarity transformations integrated out. Specifically, it works with the offset-normal shape distribution as a probability model for statistical inference on a sample of a temporal sequence of landmark configurations. This enables inference for Gaussian processes from configurations onto the shape space. The book is divided in two parts, with the first three chapters covering material on the offset-normal shape distribution, and the remaining chapters covering the theory of NonParametric Combination (NPC) tests. The chapters offer a collection of applications which are bound together by the theme of this book. They refer to the analysis of data from the FG-NET (Face and Gesture Recognition Research Network) database with facial expressions. For these data, it may be desirable to provide a description of the dynamics of the expressions, or testing whether there is a difference between the dynamics of two facial expressions or testing which of the landmarks are more informative in explaining the pattern of an expression.

An Introduction to the Advanced Theory and Practice of Nonparametric Econometrics

An Introduction to the Advanced Theory and Practice of Nonparametric Econometrics PDF Author: Jeffrey S. Racine
Publisher: Cambridge University Press
ISBN: 1108757286
Category : Business & Economics
Languages : en
Pages : 436

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Book Description
Interest in nonparametric methodology has grown considerably over the past few decades, stemming in part from vast improvements in computer hardware and the availability of new software that allows practitioners to take full advantage of these numerically intensive methods. This book is written for advanced undergraduate students, intermediate graduate students, and faculty, and provides a complete teaching and learning course at a more accessible level of theoretical rigor than Racine's earlier book co-authored with Qi Li, Nonparametric Econometrics: Theory and Practice (2007). The open source R platform for statistical computing and graphics is used throughout in conjunction with the R package np. Recent developments in reproducible research is emphasized throughout with appendices devoted to helping the reader get up to speed with R, R Markdown, TeX and Git.

Semi- and Non-parametric Methods for Interval Censored Data with Shape Constraints

Semi- and Non-parametric Methods for Interval Censored Data with Shape Constraints PDF Author: Clifford Isaac Anderson-Bergman
Publisher:
ISBN: 9781303810138
Category :
Languages : en
Pages : 213

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Book Description
Interval censoring occurs when event times are known to have occurred within an interval, rather than observing the exact time of event. This includes observations that are right censored, left censored and contained in intervals such that the left side is greater than the origin and the right side is finite (i.e. neither right censored or left censored). For interval censored data, the most common survival estimator used is the non-parametric maximum likelihood estimator (NPMLE), a generalization of the Kaplan-Meier curve which does not require any uncensored event times. The popularity of this estimator is due in part to the fact that assessing model fit for interval censored data can be very difficult. However, the extreme flexibility of the estimator comes at the cost of high variance, often providing an n^(1/3) convergence rate rather than the more typical n^(1/2). In a compromise between a highly constrained parametric estimator and the overly flexible NPMLE, we apply the popular log-concave density constraint to the NPMLE. By constraining a non-parametric estimator to have a log-concave density, an inves- tigator can improve the performance without needing to select a parametric family or smoothing parameter. We describe a fast algorithm we have developed for finding the log-concave NPMLE for interval censored data. We demonstrate that using the constraint significantly reduces the variance of the survival estimates in comparison to the unconstrained NPMLE via simulations. Next, we present three inference methods for our new estimator. This includes a goodness of fit test, two methods of confidence interval construction and a Cox PH model which incorporates a baseline log-concave distribution. We evaluate the power of the goodness of fit test and compare the other inference methods with the unconstrained counterparts via simulation. We apply these methods to a study on the effects of different environments on the rates of lung cancer among mice and another study investigating age at menopause. While our work demonstrates that the application of the shape constraints can be very helpful in the context of interval censored data, in some situations the log- concave constraint may not allow for as heavy tailed distributions as the investigator would like. To address this, we propose a new, more flexible "inverse convex" shape constraint, examine its behavior via simulation and show that it provides a better fit than the log-concave estimator when applied to real income data, which is well known to be heavy tailed. We are very optimistic about applying this new estimator to censored data, although we have yet to implement an algorithm to do so. We end this work with an algorithm for finding the (unconstrained) bivariate NPMLE for interval censored data. The bivariate NPMLE is used when each subject has two censored outcomes and the investigator is interested in modeling the relation between the two outcomes. Quickly finding the NPMLE has proven to be a challenging computational problem, as the number of parameters to consider is of order O(n^2). We present an efficient EM algorithm to find the bivariate NPMLE. We note that this is not related to shape constrained estimation.

Nonparametric and Semiparametric Models

Nonparametric and Semiparametric Models PDF Author: Wolfgang Härdle
Publisher: Springer Science & Business Media
ISBN: 9783540207221
Category : Business & Economics
Languages : en
Pages : 340

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Book Description
The statistical and mathematical principles of smoothing with a focus on applicable techniques are presented in this book. It naturally splits into two parts: The first part is intended for undergraduate students majoring in mathematics, statistics, econometrics or biometrics whereas the second part is intended to be used by master and PhD students or researchers. The material is easy to accomplish since the e-book character of the text gives a maximum of flexibility in learning (and teaching) intensity.

Nonparametric and Semiparametric Models

Nonparametric and Semiparametric Models PDF Author: Wolfgang Karl Härdle
Publisher: Springer Science & Business Media
ISBN: 364217146X
Category : Mathematics
Languages : en
Pages : 317

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Book Description
The statistical and mathematical principles of smoothing with a focus on applicable techniques are presented in this book. It naturally splits into two parts: The first part is intended for undergraduate students majoring in mathematics, statistics, econometrics or biometrics whereas the second part is intended to be used by master and PhD students or researchers. The material is easy to accomplish since the e-book character of the text gives a maximum of flexibility in learning (and teaching) intensity.

Handbook of Methods for Designing, Monitoring, and Analyzing Dose-Finding Trials

Handbook of Methods for Designing, Monitoring, and Analyzing Dose-Finding Trials PDF Author: John O'Quigley
Publisher: CRC Press
ISBN: 149874611X
Category : Mathematics
Languages : en
Pages : 306

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Book Description
Handbook of Methods for Designing, Monitoring, and Analyzing Dose-Finding Trials gives a thorough presentation of state-of-the-art methods for early phase clinical trials. The methodology of clinical trials has advanced greatly over the last 20 years and, arguably, nowhere greater than that of early phase studies. The need to accelerate drug development in a rapidly evolving context of targeted therapies, immunotherapy, combination treatments and complex group structures has provided the stimulus to these advances. Typically, we deal with very small samples, sequential methods that need to be efficient, while, at the same time adhering to ethical principles due to the involvement of human subjects. Statistical inference is difficult since the standard techniques of maximum likelihood do not usually apply as a result of model misspecification and parameter estimates lying on the boundary of the parameter space. Bayesian methods play an important part in overcoming these difficulties, but nonetheless, require special consideration in this particular context. The purpose of this handbook is to provide an expanded summary of the field as it stands and also, through discussion, provide insights into the thinking of leaders in the field as to the potential developments of the years ahead. With this goal in mind we present: An introduction to the field for graduate students and novices A basis for more established researchers from which to build A collection of material for an advanced course in early phase clinical trials A comprehensive guide to available methodology for practicing statisticians on the design and analysis of dose-finding experiments An extensive guide for the multiple comparison and modeling (MCP-Mod) dose-finding approach, adaptive two-stage designs for dose finding, as well as dose–time–response models and multiple testing in the context of confirmatory dose-finding studies. John O’Quigley is a professor of mathematics and research director at the French National Institute for Health and Medical Research based at the Faculty of Mathematics, University Pierre and Marie Curie in Paris, France. He is author of Proportional Hazards Regression and has published extensively in the field of dose finding. Alexia Iasonos is an associate attending biostatistician at the Memorial Sloan Kettering Cancer Center in New York. She has over one hundred publications in the leading statistical and clinical journals on the methodology and design of early phase clinical trials. Dr. Iasonos has wide experience in the actual implementation of model based early phase trials and has given courses in scientific meetings internationally. Björn Bornkamp is a statistical methodologist at Novartis in Basel, Switzerland, researching and implementing dose-finding designs in Phase II clinical trials. He is one of the co-developers of the MCP-Mod methodology for dose finding and main author of the DoseFinding R package. He has published numerous papers on dose finding, nonlinear models and Bayesian statistics, and in 2013 won the Royal Statistical Society award for statistical excellence in the pharmaceutical industry.

Recent Advances in Computer Vision

Recent Advances in Computer Vision PDF Author: Mahmoud Hassaballah
Publisher: Springer
ISBN: 3030030008
Category : Technology & Engineering
Languages : en
Pages : 425

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Book Description
This book presents a collection of high-quality research by leading experts in computer vision and its applications. Each of the 16 chapters can be read independently and discusses the principles of a specific topic, reviews up-to-date techniques, presents outcomes, and highlights the challenges and future directions. As such the book explores the latest trends in fashion creative processes, facial features detection, visual odometry, transfer learning, face recognition, feature description, plankton and scene classification, video face alignment, video searching, and object segmentation. It is intended for postgraduate students, researchers, scholars and developers who are interested in computer vision and connected research disciplines, and is also suitable for senior undergraduate students who are taking advanced courses in related topics. However, it is also provides a valuable reference resource for practitioners from industry who want to keep abreast of recent developments in this dynamic, exciting and profitable research field.