Regression
Machine learning model closely predicts patient waiting times for CT, MRI
"We noticed that most patients who were dissatisfied with the displayed waiting times were delayed for longer than predicted, so the need for more accurate models became imminent," Curtis et al. said. "We also wanted to predict not only waiting times for walk-in facilities, but also delays for the scheduled facilities." Stepping outside of existing research, Curtis and her co-authors zoned in on machine learning, an artificial intelligence modality that can reflect sophisticated trends otherwise difficult to capture with traditional regression approaches. Machine learning models can also resist noise, adapt to changing environments and run without human supervision, the researchers wrote, which fit the needs of a waiting room to a T. The team considered CT exams, MRI, ultrasound and radiography--only the last of which offered walk-in appointments--for the study. They evaluated 10 machine learning algorithms, including neural network, random forest, support vector machine, elastic net, multivariate adaptive regression splines, k-th nearest neighbor and linear regression, to find the algorithm that most closely predicted waiting times.
Machine learning model closely predicts patient waiting times for CT, MRI
"We noticed that most patients who were dissatisfied with the displayed waiting times were delayed for longer than predicted, so the need for more accurate models became imminent," Curtis et al. said. "We also wanted to predict not only waiting times for walk-in facilities, but also delays for the scheduled facilities." Stepping outside of existing research, Curtis and her co-authors zoned in on machine learning, an artificial intelligence modality that can reflect sophisticated trends otherwise difficult to capture with traditional regression approaches. Machine learning models can also resist noise, adapt to changing environments and run without human supervision, the researchers wrote, which fit the needs of a waiting room to a T. The team considered CT exams, MRI, ultrasound and radiography--only the last of which offered walk-in appointments--for the study. They evaluated 10 machine learning algorithms, including neural network, random forest, support vector machine, elastic net, multivariate adaptive regression splines, k-th nearest neighbor and linear regression, to find the algorithm that most closely predicted waiting times.
The 10 Statistical Techniques Data Scientists Need to Master
Regardless of where you stand on the matter of Data Science sexiness, it's simply impossible to ignore the continuing importance of data, and our ability to analyze, organize, and contextualize it. Drawing on their vast stores of employment data and employee feedback, Glassdoor ranked Data Scientist #1 in their 25 Best Jobs in America list. So the role is here to stay, but unquestionably, the specifics of what a Data Scientist does will evolve. With technologies like Machine Learning becoming ever-more common place, and emerging fields like Deep Learning gaining significant traction amongst researchers and engineers -- and the companies that hire them -- Data Scientists continue to ride the crest of an incredible wave of innovation and technological progress. While having a strong coding ability is important, data science isn't all about software engineering (in fact, have a good familiarity with Python and you're good to go).
Large-scale Nonlinear Variable Selection via Kernel Random Features
Gregorovรก, Magda, Ramapuram, Jason, Kalousis, Alexandros, Marchand-Maillet, Stรฉphane
We propose a new method for input variable selection in nonlinear regression. The method is embedded into a kernel regression machine that can model general nonlinear functions, not being a priori limited to additive models. This is the first kernel-based variable selection method applicable to large datasets. It sidesteps the typical poor scaling properties of kernel methods by mapping the inputs into a relatively low-dimensional space of random features. The algorithm discovers the variables relevant for the regression task together with learning the prediction model through learning the appropriate nonlinear random feature maps. We demonstrate the outstanding performance of our method on a set of large-scale synthetic and real datasets.
Two Use Cases of Machine Learning for SDN-Enabled IP/Optical Networks: Traffic Matrix Prediction and Optical Path Performance Prediction
Choudhury, Gagan, Lynch, David, Thakur, Gaurav, Tse, Simon
We describe two applications of machine learning in the context of IP/Optical networks. The first one allows agile management of resources at a core IP/Optical network by using machine learning for short-term and long-term prediction of traffic flows and joint global optimization of IP and optical layers using colorless/directionless (CD) flexible ROADMs. Multilayer coordination allows for significant cost savings, flexible new services to meet dynamic capacity needs, and improved robustness by being able to proactively adapt to new traffic patterns and network conditions. The second application is important as we migrate our metro networks to Open ROADM networks, to allow physical routing without the need for detailed knowledge of optical parameters. We discuss a proof-of-concept study, where detailed performance data for wavelengths on a current flexible ROADM network is used for machine learning to predict the optical performance of each wavelength. Both applications can be efficiently implemented by using a SDN (Software Defined Network) controller.
Artificial Intelligence #2: Polynomial & Logistic Regression
In statistics, Logistic Regression, or logit regression, or logit model is a regression model where the dependent variable (DV) is categorical. This article covers the case of a binary dependent variable--that is, where the output can take only two values, "0" and "1", which represent outcomes such as pass/fail, win/lose, alive/dead or healthy/sick. Cases where the dependent variable has more than two outcome categories may be analysed in multinomial logistic regression, or, if the multiple categories are ordered, in ordinal logistic regression. In the terminology of economics, logistic regression is an example of a qualitative response/discrete choice model. Logistic Regression was developed by statistician David Cox in 1958.
Modeling and Simultaneously Removing Bias via Adversarial Neural Networks
Moore, John, Pfeiffer, Joel, Wei, Kai, Iyer, Rishabh, Charles, Denis, Gilad-Bachrach, Ran, Boyles, Levi, Manavoglu, Eren
In real world systems, the predictions of deployed Machine Learned models affect the training data available to build subsequent models. This introduces a bias in the training data that needs to be addressed. Existing solutions to this problem attempt to resolve the problem by either casting this in the reinforcement learning framework or by quantifying the bias and re-weighting the loss functions. In this work, we develop a novel Adversarial Neural Network (ANN) model, an alternative approach which creates a representation of the data that is invariant to the bias. We take the Paid Search auction as our working example and ad display position features as the confounding features for this setting. We show the success of this approach empirically on both synthetic data as well as real world paid search auction data from a major search engine.
RSG: Beating Subgradient Method without Smoothness and Strong Convexity
In this paper, we study the efficiency of a {\bf R}estarted {\bf S}ub{\bf G}radient (RSG) method that periodically restarts the standard subgradient method (SG). We show that, when applied to a broad class of convex optimization problems, RSG method can find an $\epsilon$-optimal solution with a low complexity than SG method. In particular, we first show that RSG can reduce the dependence of SG's iteration complexity on the distance between the initial solution and the optimal set to that between the $\epsilon$-level set and the optimal set. In addition, we show the advantages of RSG over SG in solving three different families of convex optimization problems. (a) For the problems whose epigraph is a polyhedron, RSG is shown to converge linearly. (b) For the problems with local quadratic growth property, RSG has an $O(\frac{1}{\epsilon}\log(\frac{1}{\epsilon}))$ iteration complexity. (c) For the problems that admit a local Kurdyka-\L ojasiewicz property with a power constant of $\beta\in[0,1)$, RSG has an $O(\frac{1}{\epsilon^{2\beta}}\log(\frac{1}{\epsilon}))$ iteration complexity. On the contrary, with only the standard analysis, the iteration complexity of SG is known to be $O(\frac{1}{\epsilon^2})$ for these three classes of problems. The novelty of our analysis lies at exploiting the lower bound of the first-order optimality residual at the $\epsilon$-level set. It is this novelty that allows us to explore the local properties of functions (e.g., local quadratic growth property, local Kurdyka-\L ojasiewicz property, more generally local error bounds) to develop the improved convergence of RSG. We demonstrate the effectiveness of the proposed algorithms on several machine learning tasks including regression and classification.
US army boffins use AI to spot faces in the dark
US army researchers have developed a convolutional neural network and a range of algorithms to recognise faces in the dark. "This technology enables matching between thermal face images and existing biometric face databases or watch lists that only contain visible face imagery," explained Benjamin Riggan on Monday, co-author of the study and an electronics engineer at the US army laboratory. "The technology provides a way for humans to visually compare visible and thermal facial imagery through thermal-to-visible face synthesis." The thermal images are processed and passed to a convolutional neural network to extract facial features using landmarks that mark the corners of the eyes, nose and lips to determine its overall shape. The system, dubbed "multi-region synthesis" is trained with a loss function so that the error between the thermal images and the visible ones is minimized, creating an accurate portrayal of what someone's face looks like despite only glimpsing it in the dark.