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Feature Extraction and Automated Classification of Heartbeats by Machine Learning

arXiv.org Machine Learning

We present algorithms for the detection of a class of heart arrhythmias with the goal of eventual adoption by practicing cardiologists. In clinical practice, detection is based on a small number of meaningful features extracted from the heartbeat cycle. However, techniques proposed in the literature use high dimensional vectors consisting of morphological, and time based features for detection. Using electrocardiogram (ECG) signals, we found smaller subsets of features sufficient to detect arrhythmias with high accuracy. The features were found by an iterative step-wise feature selection method. We depart from common literature in the following aspects: 1. As opposed to a high dimensional feature vectors, we use a small set of features with meaningful clinical interpretation, 2. we eliminate the necessity of short-duration patient-specific ECG data to append to the global training data for classification 3. We apply semi-parametric classification procedures (in an ensemble framework) for arrhythmia detection, and 4. our approach is based on a reduced sampling rate of ~ 115 Hz as opposed to 360 Hz in standard literature.


Kernel Density Estimation for Dynamical Systems

arXiv.org Machine Learning

We study the density estimation problem with observations generated by certain dynamical systems that admit a unique underlying invariant Lebesgue density. Observations drawn from dynamical systems are not independent and moreover, usual mixing concepts may not be appropriate for measuring the dependence among these observations. By employing the $\mathcal{C}$-mixing concept to measure the dependence, we conduct statistical analysis on the consistency and convergence of the kernel density estimator. Our main results are as follows: First, we show that with properly chosen bandwidth, the kernel density estimator is universally consistent under $L_1$-norm; Second, we establish convergence rates for the estimator with respect to several classes of dynamical systems under $L_1$-norm. In the analysis, the density function $f$ is only assumed to be H\"{o}lder continuous which is a weak assumption in the literature of nonparametric density estimation and also more realistic in the dynamical system context. Last but not least, we prove that the same convergence rates of the estimator under $L_\infty$-norm and $L_1$-norm can be achieved when the density function is H\"{o}lder continuous, compactly supported and bounded. The bandwidth selection problem of the kernel density estimator for dynamical system is also discussed in our study via numerical simulations.


Multiple-Instance Logistic Regression with LASSO Penalty

arXiv.org Machine Learning

In this work, we consider a manufactory process which can be described by a multiple-instance logistic regression model. In order to compute the maximum likelihood estimation of the unknown coefficient, an expectation-maximization algorithm is proposed, and the proposed modeling approach can be extended to identify the important covariates by adding the coefficient penalty term into the likelihood function. In addition to essential technical details, we demonstrate the usefulness of the proposed method by simulations and real examples.


Demand Prediction and Placement Optimization for Electric Vehicle Charging Stations

arXiv.org Artificial Intelligence

Effective placement of charging stations plays a key role in Electric Vehicle (EV) adoption. In the placement problem, given a set of candidate sites, an optimal subset needs to be selected with respect to the concerns of both (a) the charging station service provider, such as the demand at the candidate sites and the budget for deployment, and (b) the EV user, such as charging station reachability and short waiting times at the station. This work addresses these concerns, making the following three novel contributions: (i) a supervised multi-view learning framework using Canonical Correlation Analysis (CCA) for demand prediction at candidate sites, using multiple datasets such as points of interest information, traffic density, and the historical usage at existing charging stations; (ii) a mixed-packing-and- covering optimization framework that models competing concerns of the service provider and EV users; (iii) an iterative heuristic to solve these problems by alternately invoking knapsack and set cover algorithms. The performance of the demand prediction model and the placement optimization heuristic are evaluated using real world data.


The AGI Containment Problem

arXiv.org Artificial Intelligence

There is considerable uncertainty about what properties, capabilities and motivations future AGIs will have. In some plausible scenarios, AGIs may pose security risks arising from accidents and defects. In order to mitigate these risks, prudent early AGI research teams will perform significant testing on their creations before use. Unfortunately, if an AGI has human-level or greater intelligence, testing itself may not be safe; some natural AGI goal systems create emergent incentives for AGIs to tamper with their test environments, make copies of themselves on the internet, or convince developers and operators to do dangerous things. In this paper, we survey the AGI containment problem - the question of how to build a container in which tests can be conducted safely and reliably, even on AGIs with unknown motivations and capabilities that could be dangerous. We identify requirements for AGI containers, available mechanisms, and weaknesses that need to be addressed.


Causal Discovery from Subsampled Time Series Data by Constraint Optimization

arXiv.org Artificial Intelligence

This paper focuses on causal structure estimation from time series data in which measurements are obtained at a coarser timescale than the causal timescale of the underlying system. Previous work has shown that such subsampling can lead to significant errors about the system's causal structure if not properly taken into account. In this paper, we first consider the search for the system timescale causal structures that correspond to a given measurement timescale structure. We provide a constraint satisfaction procedure whose computational performance is several orders of magnitude better than previous approaches. We then consider finite-sample data as input, and propose the first constraint optimization approach for recovering the system timescale causal structure. This algorithm optimally recovers from possible conflicts due to statistical errors. More generally, these advances allow for a robust and non-parametric estimation of system timescale causal structures from subsampled time series data.


MIT robot helps deliver babies

#artificialintelligence

Would you trust a robot to help deliver your baby? Robots could eventually play integral roles in labor wards, according to findings from MIT's Computer Science and Artificial Intelligence Laboratory. Robots are currently employed in hospitals to carry out simple actions, like dispensing medication. But can they understand patient needs and make scheduling decisions? The researchers have been working for the past two years to determine whether robots can be more than just helpful companions. They've been conducting experiments to see if a robot can serve as an effective "resource nurse."


Microsoft Mines 'Minecraft' to Study Artificial Intelligence

#artificialintelligence

In the pixelated cube world of "Minecraft," players can create almost anything their hearts desire. Now, Microsoft is using the popular world-building game to build and test artificial intelligence in the fictional environment. Microsoft has made a platform for artificial intelligence (AI) research using a modified version of "Minecraft" that will become available to the public following a limited release to select researchers. Project Malmo (formerly known as Project AIX) allows anyone from ambitious amateur coders to advanced computer scientists to build and test artificial intelligence in the "Minecraft" environment. "We?re trying to put out the tools that will allow people to make progress on those really, really hard research questions," Katja Hofmann, the project's lead researcher, said in a Microsoft blog post announcing the release.


The importance of Alibaba's new 'Internet car'

Washington Post - Technology News

Chinese e-commerce giant Alibaba introduced its first automobile last week, the RX5 sport utility vehicle, set to be delivered to customers in August. The company called the vehicle, made with Chinese carmaker SAIC, the first "Internet car" in a news release. It will run software developed by Alibaba's YunOS division to connect with other smart devices, the company said. It will retail for 148,800 yuan, or 22,300. Alibaba in its announcement said the car will use the company's own e-commerce platform to deliver such services as finding parking spaces, locating gas stations or making restaurant reservations.


Twitter introduces significantly larger animated GIF sizes

The Independent - Tech

Nasa has announced that it has found evidence of flowing water on Mars. Scientists have long speculated that Recurring Slope Lineae -- or dark patches -- on Mars were made up of briny water but the new findings prove that those patches are caused by liquid water, which it has established by finding hydrated salts. Several hundred camped outside the London store in Covent Garden. The 6s will have new features like a vastly improved camera and a pressure-sensitive "3D Touch" display