Change Detection in Multivariate Data: Likelihood and Detectability LossGiacomo Boracchi
Talk at IBM TJ Watson, Giacomo Boracchi
Abstract
We address the problem of detecting changes in multivariate data, and we investigate the intrinsic difficulty that change-detection methods have to face when the data dimension scales. In particular, we consider algorithms that compute at first the data log-likelihood, and then detect changes by comparing the distribution of this latter over different time windows / portions of the dataset. Despite this approach constitutes the frame of several change-detection methods, its effectiveness when data dimension scales has never been investigated, which is indeed the goal of our research.
We show that the magnitude of the change can be naturally measured by the symmetric Kullback-Leibler divergence between the pre- and post-change distributions, and that the detectability of changes of a given magnitude worsens when the data dimension increases. This problem, which we refer to as "detectability loss", is due to the linear relationship between the variance of the log-likelihood and the data dimension.
We analytically derive the detectability loss on Gaussian-distributed data, and empirically demonstrate that this problem holds also in real-world datasets, where it can be harmful even at low data-dimensions. We finally discuss few implications of detectability loss, illustrating as a case study the detection of defects in SEM images of nanofibers by means of anomaly-detection algorithms based on sparse representations.
Learning In Nonstationary Environments: Perspectives And Applications. Part1:...Giacomo Boracchi
This document discusses concept drift and the challenges it poses for machine learning models when applied to streaming data. Concept drift occurs when the underlying data distribution changes over time, violating the assumption of data being independently and identically distributed (i.i.d.). This can cause classification performance to decrease unless the model adapts. The document outlines different types of concept drift and compares the performance of simple adaptation strategies, such as continuously updating the model versus only using recent data, on a toy example to demonstrate the need for more sophisticated adaptive methods.
Este documento descreve o Mestrado em Planeamento Regional e Urbano oferecido pela Universidade de Aveiro em Portugal. O curso tem duração de 2 anos e foca-se em dotar os alunos de competências para analisar e intervir sobre o território considerando suas dimensões física, ambiental, social, econômica e política. O curso admite licenciados de várias áreas e tem 45 vagas disponíveis em 3 fases de candidatura.
Delicious es un servicio web que permite a los usuarios guardar marcadores de páginas web de forma centralizada y compartirlos con otros. Los usuarios pueden visualizar sus propios marcadores desde cualquier ordenador e incluso ver los marcadores que otros han compartido. Delicious introdujo el concepto de marcadores sociales, permitiendo a los usuarios almacenar y clasificar enlaces e interactuar compartiéndolos.
1. O documento discute a arte pública na perspectiva de uma retórica total do espaço urbano, da esfera pública e do horizonte cultural.
2. O autor propõe ver a cidade como um lugar onde deliberamos sobre o passado, presente e futuro comuns, incluindo formas de ação estética e artística.
3. A cultura urbana não pode abdicar de repensar as ações de comunicação urbana propriamente ditas.
Change Detection in Multivariate Data: Likelihood and Detectability LossGiacomo Boracchi
Talk at IBM TJ Watson, Giacomo Boracchi
Abstract
We address the problem of detecting changes in multivariate data, and we investigate the intrinsic difficulty that change-detection methods have to face when the data dimension scales. In particular, we consider algorithms that compute at first the data log-likelihood, and then detect changes by comparing the distribution of this latter over different time windows / portions of the dataset. Despite this approach constitutes the frame of several change-detection methods, its effectiveness when data dimension scales has never been investigated, which is indeed the goal of our research.
We show that the magnitude of the change can be naturally measured by the symmetric Kullback-Leibler divergence between the pre- and post-change distributions, and that the detectability of changes of a given magnitude worsens when the data dimension increases. This problem, which we refer to as "detectability loss", is due to the linear relationship between the variance of the log-likelihood and the data dimension.
We analytically derive the detectability loss on Gaussian-distributed data, and empirically demonstrate that this problem holds also in real-world datasets, where it can be harmful even at low data-dimensions. We finally discuss few implications of detectability loss, illustrating as a case study the detection of defects in SEM images of nanofibers by means of anomaly-detection algorithms based on sparse representations.
Learning In Nonstationary Environments: Perspectives And Applications. Part1:...Giacomo Boracchi
This document discusses concept drift and the challenges it poses for machine learning models when applied to streaming data. Concept drift occurs when the underlying data distribution changes over time, violating the assumption of data being independently and identically distributed (i.i.d.). This can cause classification performance to decrease unless the model adapts. The document outlines different types of concept drift and compares the performance of simple adaptation strategies, such as continuously updating the model versus only using recent data, on a toy example to demonstrate the need for more sophisticated adaptive methods.
Este documento descreve o Mestrado em Planeamento Regional e Urbano oferecido pela Universidade de Aveiro em Portugal. O curso tem duração de 2 anos e foca-se em dotar os alunos de competências para analisar e intervir sobre o território considerando suas dimensões física, ambiental, social, econômica e política. O curso admite licenciados de várias áreas e tem 45 vagas disponíveis em 3 fases de candidatura.
Delicious es un servicio web que permite a los usuarios guardar marcadores de páginas web de forma centralizada y compartirlos con otros. Los usuarios pueden visualizar sus propios marcadores desde cualquier ordenador e incluso ver los marcadores que otros han compartido. Delicious introdujo el concepto de marcadores sociales, permitiendo a los usuarios almacenar y clasificar enlaces e interactuar compartiéndolos.
1. O documento discute a arte pública na perspectiva de uma retórica total do espaço urbano, da esfera pública e do horizonte cultural.
2. O autor propõe ver a cidade como um lugar onde deliberamos sobre o passado, presente e futuro comuns, incluindo formas de ação estética e artística.
3. A cultura urbana não pode abdicar de repensar as ações de comunicação urbana propriamente ditas.
Designing an automated and data-driven organizationIndia Quotient
This document discusses product-oriented organizational design for tech startups. It recommends designing the organization like a product with specific workflows for each team, complete access to internal data, and machine learning training for all employees. It promotes using tools like Slack, Trello, Jenkins, Ansible, New Relic, AWS and custom analytics stacks to increase productivity, automation, and data-driven decision making. The goal is to manage all aspects of the consumer product through these systems and data sources to maximize customer delight, order fulfillment, and growth.
The document discusses entrepreneurship education in India. It aims to study the significance and current status of entrepreneurship education in India, and suggest ways to improve its quality. Entrepreneurship education can help address India's challenges of unemployment, especially among youth, and the need for more job creation and economic development. While universities and institutions have started entrepreneurship programs, there are still questions around how to best structure such education - whether teaching should focus on entrepreneurship itself or managing businesses, and how to balance academic and practical experience. The document analyzes various types of entrepreneurship education programs and institutions involved in India, and provides suggestions like reducing the research gap between coursework and industry needs.
The document summarizes key points from a presentation on search engine optimization (SEO) techniques given by Jessica Bowman. The presentation covered topics such as keyword research, optimizing page content, link building strategies, integrating SEO best practices, and common SEO mistakes to avoid. Bowman emphasized the importance of optimizing for both human visitors and search engine crawlers.
Evolución del clima y Cambios Climáticosbgbocairent
El documento resume la evolución del clima a lo largo de la historia de la Tierra, desde el Precámbrico hasta el Cuaternario, destacando periodos de calentamiento, enfriamiento y glaciaciones. Explica que los cambios climáticos se deben a factores como la concentración de gases de efecto invernadero, la distribución de los continentes y la radiación solar. Finalmente, analiza el consenso científico sobre el cambio climático actual y el origen antropogénico del calentamiento.
Harold Laswell and Charles Wright were theorists who studied mass communication in the 1940s-1960s. Laswell viewed communication through a scientific lens, comparing society's functions to biological systems. Wright took a sociological approach, analyzing communication's macro and micro impacts on social cohesion. Both saw mass media as fulfilling necessary functions in surveillance, interpretation, socialization, and entertainment to maintain social stability.
- Noboru Kano introduces himself as a new grad from 2016 with interests in NLP, statistics, and machine learning. He has 1 year of experience as a ML engineer at a startup.
- The presentation will cover what chatbots are, the history of chatbots including ELIZA from 1966, types of chatbots including rule-based, dialogue database, and generative models. It will include an algorithm explanation and demo of a image captioning chatbot created by the presenter.
- Types of chatbots include rule-based using if-then statements, dialogue database matching user input to stored responses, and generative models using statistical methods like Markov chains or neural networks to generate new sentences.
Šeit apkopotas dažas šobrīd aktuālas starptautiskās iniciatīvas, kā arī UNESCO Latvijas Nacionālās komisijas izstrādāti materiāli, kurus iespējams iekļaut mācību procesā arī attālināti
Prezentācija Jelgavas Valsts ģimnāzijas Pasaules lielākajai mācību stundailiela_stunda
This document provides instructions for an activity where students will watch a video about hunger, discuss in groups the causes of hunger in Belgium, Latvia, and worldwide, brainstorm solutions to hunger on post-its, create a poster presenting their chosen solution, present their poster to another group, and then create an online meme about solving hunger problems.
Designing an automated and data-driven organizationIndia Quotient
This document discusses product-oriented organizational design for tech startups. It recommends designing the organization like a product with specific workflows for each team, complete access to internal data, and machine learning training for all employees. It promotes using tools like Slack, Trello, Jenkins, Ansible, New Relic, AWS and custom analytics stacks to increase productivity, automation, and data-driven decision making. The goal is to manage all aspects of the consumer product through these systems and data sources to maximize customer delight, order fulfillment, and growth.
The document discusses entrepreneurship education in India. It aims to study the significance and current status of entrepreneurship education in India, and suggest ways to improve its quality. Entrepreneurship education can help address India's challenges of unemployment, especially among youth, and the need for more job creation and economic development. While universities and institutions have started entrepreneurship programs, there are still questions around how to best structure such education - whether teaching should focus on entrepreneurship itself or managing businesses, and how to balance academic and practical experience. The document analyzes various types of entrepreneurship education programs and institutions involved in India, and provides suggestions like reducing the research gap between coursework and industry needs.
The document summarizes key points from a presentation on search engine optimization (SEO) techniques given by Jessica Bowman. The presentation covered topics such as keyword research, optimizing page content, link building strategies, integrating SEO best practices, and common SEO mistakes to avoid. Bowman emphasized the importance of optimizing for both human visitors and search engine crawlers.
Evolución del clima y Cambios Climáticosbgbocairent
El documento resume la evolución del clima a lo largo de la historia de la Tierra, desde el Precámbrico hasta el Cuaternario, destacando periodos de calentamiento, enfriamiento y glaciaciones. Explica que los cambios climáticos se deben a factores como la concentración de gases de efecto invernadero, la distribución de los continentes y la radiación solar. Finalmente, analiza el consenso científico sobre el cambio climático actual y el origen antropogénico del calentamiento.
Harold Laswell and Charles Wright were theorists who studied mass communication in the 1940s-1960s. Laswell viewed communication through a scientific lens, comparing society's functions to biological systems. Wright took a sociological approach, analyzing communication's macro and micro impacts on social cohesion. Both saw mass media as fulfilling necessary functions in surveillance, interpretation, socialization, and entertainment to maintain social stability.
- Noboru Kano introduces himself as a new grad from 2016 with interests in NLP, statistics, and machine learning. He has 1 year of experience as a ML engineer at a startup.
- The presentation will cover what chatbots are, the history of chatbots including ELIZA from 1966, types of chatbots including rule-based, dialogue database, and generative models. It will include an algorithm explanation and demo of a image captioning chatbot created by the presenter.
- Types of chatbots include rule-based using if-then statements, dialogue database matching user input to stored responses, and generative models using statistical methods like Markov chains or neural networks to generate new sentences.
Šeit apkopotas dažas šobrīd aktuālas starptautiskās iniciatīvas, kā arī UNESCO Latvijas Nacionālās komisijas izstrādāti materiāli, kurus iespējams iekļaut mācību procesā arī attālināti
Prezentācija Jelgavas Valsts ģimnāzijas Pasaules lielākajai mācību stundailiela_stunda
This document provides instructions for an activity where students will watch a video about hunger, discuss in groups the causes of hunger in Belgium, Latvia, and worldwide, brainstorm solutions to hunger on post-its, create a poster presenting their chosen solution, present their poster to another group, and then create an online meme about solving hunger problems.
Salaspils novada pašvaldības pirmsskolas izglītības iestāde "Atvasīte" 5 – 6 gadus veco bērnu grupiņā "Bitītes" īstenoja Pasaules lielāko mācību stundu „Katram šķīvim savs stāsts”. Autores: Karīna Gavriļčenko un Ilze Cakule.