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Serial electrocardiography to detect newly emerging or aggravating cardiac pathology: a deep-learning approach

BIOMEDICAL ENGINEERING ONLINE 2019年第1期18卷 15-15页

作者： Sbrollini, Agnese De Jongh, Marjolein C. Ter Haar, C. Cato Treskes, Roderick W. Man, Sumche Burattini, Laura Swenne, Cees A. Leiden Univ Med Ctr Cardiol Dept POB 9600 NL-2300 RC Leiden Netherlands Univ Politecn Marche Informat Engn Dept Via Brecce Bianche 12 I-60121 Ancona Italy

Background: Serial electrocardiography aims to contribute to electrocardiogram (ECG) diagnosis by comparing the ECG under consideration with a previously made ECG in the same individual. Here, we present a novel algorithm to construct dedicated deep-learning neural networks (NNs) that are specialized in detecting newly emerging or aggravating existing cardiac pathology in serial ECGs. Methods: We developed a novel deep-learning method for serial ECG analysis and tested its performance in detection of heart failure in post-infarction patients, and in the detection of ischemia in patients who underwent elective percutaneous coronary intervention. Core of the method is the repeated structuring and learning procedure that, when fed with 13 serial ECG difference features (intra-individual differences in: QRS duration;QT interval;QRS maximum;T-wave maximum;QRS integral;T-wave integral;QRS complexity;T-wave complexity;ventricular gradient;QRS-T spatial angle;heart rate;J-point amplitude;and T-wave symmetry), dynamically creates a NN of at most three hidden layers. An optimization process reduces the possibility of obtaining an inefficient NN due to adverse initialization. Results: Application of our method to the two clinical ECG databases yielded 3-layer NN architectures, both showing high testing performances (areas under the receiver operating curves were 84% and 83%, respectively). Conclusions: Our method was successful in two different clinical serial ECG applications. Further studies will investigate if other problem-specific NNs can successfully be constructed, and even if it will be possible to construct a universal NN to detect any pathologic ECG change.

关键词： Serial electrocardiography Vectorcardiography Deep learning Neural networks constructive algorithm

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Inverse Density as an Inverse Problem: the Fredholm Equation Approach 13

Inverse Density as an Inverse Problem: the Fredholm Equation...

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Annual Conference on Neural Information Processing Systems

作者： Qichao Que Mikhail Belkin Department of Computer Science and Engineering The Ohio State University

ISBN: (纸本)9781632660244

We address the problem of estimating the ratio q/p where p is a density function and q is another density, or, more generally an arbitrary function. Knowing or approximating this ratio is needed in various problems of inference and integration often referred to as importance sampling in statistical inference. It is also closely related to the problem of covariate shift in transfer learning. Our approach is based on reformulating the problem of estimating the ratio as an inverse problem in terms of an integral operator corresponding to a kernel, known as the Fredholm problem of the first kind. This formulation, combined with the techniques of reg-ularization leads to a principled framework for constructing algorithms and for analyzing them theoretically. The resulting family of algorithms (FIRE, for Fredholm Inverse Regularized Estimator) is flexible, simple and easy to implement. We provide detailed theoretical analysis including concentration bounds and convergence rates for the Gaussian kernel for densities defined on R~d and smooth d-dimensional sub-manifolds of the Euclidean space. Model selection for unsupervised or semi-supervised inference is generally a difficult problem. It turns out that in the density ratio estimation setting, when samples from both distributions are available, simple completely unsupervised model selection methods are available. We call this mechanism CD-CV for Cross-Density Cross-Validation. We show encouraging experimental results including applications to classification within the covariate shift framework.

关键词： Inverse method Density functions Fredholm equations Transfer (Psychology) Statistical inference Seeds importance sampling Theoretical analysis model selection Inverse integration constructive algorithm

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An Efficient Construction algorithm for Binary Interval Tree Nodes

An Efficient Construction Algorithm for Binary Interval Tree...

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2010 International Conference on Audio,Language and Image Processing(2010年音频、语言与图像处理国际会议 ICALIP 2010)

作者： Pan Wang Si-kun Li Xun Cai Liang Zeng School of Computer Science and Technology National University of Defense Technology Hunan Changsha 410073 China

ISBN: (纸本)9781424458653

The preprocessing almost take half of the whole time in isosurface extraction of large-scale data, thus it will make sense to shorten the preprocessing time to improve visualization efficiency. We develop a new construction algorithm for binary interval tree nodes based on partitioning span space, and it reduce the sorting computation considerably in isosurface extraction preprocessing. Both complexity analysis and experiments demonstrate the effectiveness of our new technique, and it has 50％ around performance promotion in our test data sets. So the new algorithm is practical in large-scale data isosurface extraction, especially for the real-time visualization system.

关键词： constructive algorithm tree nodes Isosurfaces New constructions Pretreatment new technique observational data Binary Complexity Analysis

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Layered_CasPer: Layered cascade artificial neural networks

Layered_CasPer: Layered cascade artificial neural networks

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International Joint Conference on Neural Networks

作者： Tengfei Shen Dingyun Zhu Research School of Computer Science College of Engineering and Computer Science The Australian National University

ISBN: (纸本)9781467314886

Previous research has demonstrated that constructive algorithms are powerful methods for training feedforward neural networks. The CasPer algorithm is a constructive neural network algorithm that generates networks from a simple architecture and then expands it. The A_CasPer algorithm is a modified version of the CasPer algorithm which uses a candidate pool instead of a single neuron being trained. This research adds an extension to the A_CasPer algorithm in terms of the network architecture - the Layered_CasPer algorithm. The hidden neurons form as layers in the new version of the network structure which results in less computational cost being required. Beyond the network structure, other aspects of Layered_CasPer are the same as A_CasPer. The Layered_CasPer algorithm extension is benchmarked on a number of classification problems and compared to other constructive algorithms, which are CasCor, CasPer, A_CasPer, and AT_CasPer. It is shown that Layered_CasPer has a better performance on the datasets which have a large number of inputs for classification tasks. The Layered_CasPer algorithm has an advantage over other cascade style constructive algorithms in being more similar in topology to the familiar layered structure of traditional feedforward neural networks.

关键词： Cascade constructive algorithms Feedforward neural network CasPer A_CasPer CasCor AT_CasPer Layered_CasPer feedforward neural nets NETWORK STRUCTURE Artificial neural networks algorithms constructivity cascades Dataset constructive algorithm topology

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Incremental computation of complex object queries 01

Incremental computation of complex object queries

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ACM SIGPLAN Conference on Object-oriented Programming, Systems, Languages, and Applications

作者： Hiroaki Nakamura IBM Research Tokyo Research Laboratory 1623-14 Shimotsuruma Yamato-shi Kanagawa-ken 242-8502 Japan

ISBN: (纸本)1581133359

The need for incremental algorithms for evaluating database queries is well known, but constructing algorithms that work on object-oriented databases (OODBs) has been difficult. The reason is that OODB query languages involve complex data types including composite objects and nested collections. As a result, existing algorithms have limitations in that the kinds of database updates are restricted, the operations found in many query languages are not supported, or the algorithms are too complex to be described precisely. We present an incremental computation algorithm that can handle any kind of database updates, can accept any expressions in complex query languages such as OQL, and can be described precisely. By translating primitive values and records into collections, we can reduce all query expressions comprehension. This makes the problems with incremental computation less complicated and thus allows us to decribe of two parts: one is to maintain the consistency in each comprehension occurrence and the other is to update the value of an entire expression. The algorithm is so flexible that we can use strict updates, lazy updates, and their combinations. By comparing the performance of applications built with our mechanism and that of equivalent hand written update programs, we show that our incremental algorithm can be iplemented efficiently.

关键词： data base language Incremental algorithms data types data querying object-oriented databases arithmetic constructive algorithm

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ACTION RECOGNITION USING SALIENT NEIGHBORING HISTOGRAMS

ACTION RECOGNITION USING SALIENT NEIGHBORING HISTOGRAMS

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IEEE International Conference on Image Processing

作者： Huamin Ren Thomas B. Moeslund Visual Analysis of People Lab Aalborg University Denmark

ISBN: (纸本)9781479923427

Combining spatio-temporal interest points with Bag-of-Words models achieves state-of-the-art performance in action recognition. However, existing methods based on "bag-of-words" models either are too local to capture the variance in space/time or fail to solve the ambiguity problem in spatial and temporal dimensions. Instead, we propose a salient vocabulary construction algorithm to select visual words from a global point of view, and form compact descriptors to represent discriminative histograms in the neighborhoods. Those salient neighboring histograms are then trained to model different actions. Our approach yields a competitive result on the KTH dataset compare to state-of-the-art methods. On the more challenging UCF Sports dataset, we obtain 95.21%, which is approximately 4% better than the current best published results.

关键词： Salient visual words neighboring histograms action recognition histograms Word Spacetime Dataset constructive algorithm

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A novel online recalibration strategy for continuous glucose measurement sensors employing LMI techniques

A novel online recalibration strategy for continuous glucose...

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Annual International Conference of the IEEE Engineering in Medicine and Biology Society

作者： Harald Kirchsteiger Luca Zaccarian Eric Renard Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz 4040

ISBN: (纸本)9781457702150

This paper considers the problem of online calibration and recalibration of continuous glucose monitoring devices. A parametric relation between interstitial and blood glucose is investigated and a constructive algorithm to adaptively estimate the parameters within this relation is proposed. The algorithm explicitly considers measurement uncertainty of the device used to collect the calibration measurements and enables automatic detection of measurements which are not suitable to be used for calibration. The method was assessed on clinical data from 17 diabetic patients and the improvements with respect to the current state of the art is shown.

关键词： recalibration constructive algorithm Blood Glucose automatic detection measurement uncertainty Interim Local Management Interface current status Arts state of the art diabetic patient interstitial

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On a Converse theorem for Finite-time Lyapunov Functions to Estimate Domains of Attraction

On a Converse theorem for Finite-time Lyapunov Functions to ...

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American Control Conference

作者： Ayush Pandey Aaron D. Ames Department of Control and Dynamical Systems California Institute of Technology Pasadena CA

ISBN: (数字)9781538682661

ISBN: (纸本)9781538682678

The main result of the paper is a new converse theorem for finite-time Lyapunov functions. We show the existence of a finite-time Lyapunov function for an autonomous continuous-time nonlinear dynamical system if the origin of the system is asymptotically stable. Our proof extends the recent results in finite-time Lyapunov function theory by providing an alternative converse proof for the existence of finite-time Lyapunov functions. In particular, we show that given asymptotic stability of the origin, the linearized dynamics satisfy global finite-time Lyapunov function conditions hence proving the converse theorem. Using our results, we present a consolidated theory for using and constructing Lyapunov functions to certify system stability properties. We also propose a constructive algorithm to efficiently compute non-conservative estimates of the domain of attraction for nonlinear dynamical systems.

关键词： Liapunov function Converse Attraction Nonlinear dynamical systems Phyla Theorem constructive algorithm region of attraction

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Discovering the Structure of a Planar Mirror System from Multiple Observations of a Single Point

Discovering the Structure of a Planar Mirror System from Mul...

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IEEE Conference on Computer Vision and Pattern Recognition

作者： Ilya Reshtouski Alkhazur Manakov Ayush Bhandari Ramesh Raskar Hans-Peter Seidel Ivo Ihrke Saarland University MIT Media Lab MPI Informatik

ISBN: (纸本)9781467364102

We investigate the problem of identifying the position of a viewer inside a room of planar mirrors with unknown geometry in conjunction with the room's shape parameters. We consider the observations to consist of angularly resolved depth measurements of a single scene point that is being observed via many multi-bounce interactions with the specular room geometry. Applications of this problem statement include areas such as calibration, acoustic echo cancelation and time-of-flight imaging. We theoretically analyze the problem and derive sufficient conditions for a combination of convex room geometry, observer, and scene point to be reconstructable. The resulting constructive algorithm is exponential in nature and, therefore, not directly applicable to practical scenarios. To counter the situation, we propose theoretically devised geometric constraints that enable an efficient pruning of the solution space and develop a heuristic randomized search algorithm that uses these constraints to obtain an effective solution. We demonstrate the effectiveness of our algorithm on extensive simulations as well as in a challenging real-world calibration scenario.

关键词： cancelation time-of-flight imaging therefore single turnout CANCELLATIONS Solution space Mirrors geometric constraint Viewer Device Component Planar Exploration Echo cancellers SEARCHING algorithm geometry Rooms constructive algorithm

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On the Construction of In-Block Controllable Covers of Nonlinear Systems on Polytopes

On the Construction of In-Block Controllable Covers of Nonli...

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IEEE Annual Conference on Decision and Control

作者： Mohamed K. Helwa Peter E. Caines Department of Electrical and Computer Engineering and Centre for Intelligent Machines (CIM) McGill University Montreal Quebec H3A 0E9 Canada

ISBN: (纸本)9781479978878

This paper initiates the study of the problem of constructing in-block controllable covers of nonlinear systems on polytopes, which is useful in studying approximate mutual accessibility problems of nonlinear systems on polytopes. In particular, for a given nonlinear system and a given polytope, we study how to systematically construct polytopic covers of the given polytope such that the affine systems, resulting from the linearization of the nonlinear system inside the polytopic regions of the cover, are in-block controllable. By exploring the geometry of the problem, we first provide some constructive guidelines for building such covers. Then, for a special class of nonlinear systems, we provide a constructive algorithm. We also give illustrative examples of the main results.

关键词： Polytopes constructive algorithm Linearization

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