Europe
Power System Parameters Forecasting Using Hilbert-Huang Transform and Machine Learning
Kurbatsky, Victor, Tomin, Nikita, Spiryaev, Vadim, Leahy, Paul, Sidorov, Denis, Zhukov, Alexei
A novel hybrid data-driven approach is developed for forecasting power system parameters with the goal of increasing the efficiency of short-term forecasting studies for non-stationary time-series. The proposed approach is based on mode decomposition and a feature analysis of initial retrospective data using the Hilbert-Huang transform and machine learning algorithms. The random forests and gradient boosting trees learning techniques were examined. The decision tree techniques were used to rank the importance of variables employed in the forecasting models. The Mean Decrease Gini index is employed as an impurity function. The resulting hybrid forecasting models employ the radial basis function neural network and support vector regression. Apart from introduction and references the paper is organized as follows. The section 2 presents the background and the review of several approaches for short-term forecasting of power system parameters. In the third section a hybrid machine learning-based algorithm using Hilbert-Huang transform is developed for short-term forecasting of power system parameters. Fourth section describes the decision tree learning algorithms used for the issue of variables importance. Finally in section six the experimental results in the following electric power problems are presented: active power flow forecasting, electricity price forecasting and for the wind speed and direction forecasting.
Data mining for censored time-to-event data: A Bayesian network model for predicting cardiovascular risk from electronic health record data
Bandyopadhyay, Sunayan, Wolfson, Julian, Vock, David M., Vazquez-Benitez, Gabriela, Adomavicius, Gediminas, Elidrisi, Mohamed, Johnson, Paul E., O'Connor, Patrick J.
Models for predicting the risk of cardiovascular events based on individual patient characteristics are important tools for managing patient care. Most current and commonly used risk prediction models have been built from carefully selected epidemiological cohorts. However, the homogeneity and limited size of such cohorts restricts the predictive power and generalizability of these risk models to other populations. Electronic health data (EHD) from large health care systems provide access to data on large, heterogeneous, and contemporaneous patient populations. The unique features and challenges of EHD, including missing risk factor information, non-linear relationships between risk factors and cardiovascular event outcomes, and differing effects from different patient subgroups, demand novel machine learning approaches to risk model development. In this paper, we present a machine learning approach based on Bayesian networks trained on EHD to predict the probability of having a cardiovascular event within five years. In such data, event status may be unknown for some individuals as the event time is right-censored due to disenrollment and incomplete follow-up. Since many traditional data mining methods are not well-suited for such data, we describe how to modify both modelling and assessment techniques to account for censored observation times. We show that our approach can lead to better predictive performance than the Cox proportional hazards model (i.e., a regression-based approach commonly used for censored, time-to-event data) or a Bayesian network with {\em{ad hoc}} approaches to right-censoring. Our techniques are motivated by and illustrated on data from a large U.S. Midwestern health care system.
Probabilistic Archetypal Analysis
Seth, Sohan, Eugster, Manuel J. A.
Archetypal analysis (AA) represents observations as composition of pure patterns, i.e., archetypes, or equivalently convex combinations of extreme values (Cutler and Breiman, 1994). Although AA bears resemblance with many well established prototypical analysis tools, such as principal component analysis (PCA, Mohamed et al, 2009), nonnegative matrix factorization (NMF, F evotte and Idier, 2011), probabilistic latent semantic analysis (Hofmann, 2013), andk -means (Steinley, 2006); AA is arguably unique, both conceptually and computationally . Conceptually, AA imitates the human tendency of representing a group of objects by its extreme elements (Davis and Love, 2010): this makes AA an interesting exploratory tool for applied scientists (e.g., Eugster, 2012; Seiler and Wohlrabe, 2013). Computationally, AA is data-driven, and requires the factors to be probability vectors: these make AA a computationally demanding tool, yet brings better interpretability . The concept of AA was originally formulated by Cutler and Breiman (1994).
Structural Intervention Distance (SID) for Evaluating Causal Graphs
Peters, Jonas, Bühlmann, Peter
Causal inference relies on the structure of a graph, often a directed acyclic graph (DAG). Different graphs may result in different causal inference statements and different intervention distributions. To quantify such differences, we propose a (pre-) distance between DAGs, the structural intervention distance (SID). The SID is based on a graphical criterion only and quantifies the closeness between two DAGs in terms of their corresponding causal inference statements. It is therefore well-suited for evaluating graphs that are used for computing interventions. Instead of DAGs it is also possible to compare CPDAGs, completed partially directed acyclic graphs that represent Markov equivalence classes. Since it differs significantly from the popular Structural Hamming Distance (SHD), the SID constitutes a valuable additional measure. We discuss properties of this distance and provide an efficient implementation with software code available on the first author's homepage (an R package is under construction).
AAAI Conferences Calendar
DISASTER ROBOTICS LOGIC IN GAMES Robin R. Murphy Johan van Benthem "A thorough overview and A comprehensive examination intellectually stimulating of the interfaces of logic, treatment of foundational and computer science, and game advanced concepts by one of theory, drawing on twenty the pioneers in the field, this years of research on logic book is an authoritative refer-and games. HCOMP 2013 to be Held in Pittsburgh! The Second AAAI Conference on Human Computation and Crowdsourcing (HCOMP-2014) will be held November 2-4 in Pittsburgh, Pennsylvania, USA. The HCOMP conference is cross-disciplinary, and invites submissions across the broad spectrum of crowdsourcing and human computation work. Human computation and crowdsourcing is unique in its direct engagement and reliance on both human-centered studies and traditional computer science.
AI Challenge Problem: Scalable Models for Patterns of Life
Folsom-Kovarik, J. T. (Soar Technology, Inc.) | Schatz, Sae (MESH Solutions, LLC, a DSCI Company) | Jones, Randolph M. (Soar Technology, Inc.) | Bartlett, Kathleen (MESH Solutions, LLC, a DSCI Company) | Wray, Robert E. (Soar Technology, Inc.)
Innovative Applications of Artificial Intelligence 2013
Muñoz-Avila, Héctor (Lehigh University) | Stracuzzi, David (Sandia National Laboratories)
These articles were selected for their description of AI technologies that are either in practical use or close to it. Five of the articles describe deployed application case studies. These articles present fielded AI applications that distinguish themselves for their innovative use of AI technology. One article describes an emerging application. It presents an area where AI technology can have a practical impact. Another article describes a challenge problem; it presents to the AI community at large a problem where AI could make a significant difference.
A Constraint-Based Dental School Timetabling System
Cambazard, Hadrien (Université de Grenoble) | O' (University College Cork) | Sullivan, Barry (University College Cork) | Simonis, Helmut
We describe a constraint-based timetabling system that was developed for the dental school based at Cork University Hospital in Ireland. This sy stem has been deployed since 2010. Dental school timetabling differs from other university course scheduling in that certain clinic sessions can be used by multiple courses at the same time, provided a limit on room capacity is satisfied. Starting from a constraint programming solution using a web interface, we have moved to a mixed integer programming-based solver to deal with multiple objective functions, along with a dedicated Java application, which provides a rich user interface. Solutions for the years 2010, 2011 and 2012 have been used in the dental school, replacing a manual timetabling process, which could no longer cope with increasing student numbers and resulting resource bottlenecks. The use of the automated system allowed the dental school to increase the number of students enrolled to the maximum possible given the available resources. It also provides the school with a valuable “what-if” analysis tool.
Integrating Digital Pens in Breast Imaging for Instant Knowledge Acquisition
Sonntag, Daniel (German Research Center for AI) | Weber, Markus (German Research Center for AI) | Cavallaro, Alexander (Imaging Science Institute Erlangen) | Hammon, Matthias (Imaging Science Institute Erlangen)
Future radiology practices assume that the radiology reports should be uniform, comprehensive, and easily managed. This means that reports must be readable to humans and machines alike. In order to improve reporting practices in breast imaging, we allow the radiologist to write structured reports with a special pen on paper with an invisible dot pattern. In this way, we provide a knowledge acquisition system for printed mammography patient forms for the combined work with printed and digital documents. In this domain, printed documents cannot be easily replaced by computer systems because they contain free-form sketches and textual annotations, and the acceptance of traditional PC reporting tools is rather low among the doctors. This is due to the fact that current electronic reporting systems significantly add to the amount of time it takes to complete the reports. We describe our real-time digital paper application and focus on the use case study of our deployed application. We think that our results motivate the design and implementation of intuitive pen-based user interfaces for the medical reporting process and similar knowledge work domains. Our system imposes only minimal overhead on traditional form-filling processes and provides for a direct, ontology-based structuring of the user input for semantic search and retrieval applications, as well as other applied artificial intelligence scenarios which involve manual form-based data acquisition.
Constrained speaker linking
van Leeuwen, David A., Brümmer, Niko
In this paper we study speaker linking (a.k.a.\ partitioning) given constraints of the distribution of speaker identities over speech recordings. Specifically, we show that the intractable partitioning problem becomes tractable when the constraints pre-partition the data in smaller cliques with non-overlapping speakers. The surprisingly common case where speakers in telephone conversations are known, but the assignment of channels to identities is unspecified, is treated in a Bayesian way. We show that for the Dutch CGN database, where this channel assignment task is at hand, a lightweight speaker recognition system can quite effectively solve the channel assignment problem, with 93% of the cliques solved. We further show that the posterior distribution over channel assignment configurations is well calibrated.