Energy
ST unveils inclinometer with machine-learning core
STMicroelectronics has unveiled the IIS2ICLX, a high-accuracy, low-power, 2-axis digital inclinometer for use in applications such as industrial automation and structural-health monitoring. The device features a programmable machine-learning core and 16 independent programmable finite state machines that help edge devices to save both power and reduce data transfers to the cloud. With advanced embedded functions, the IIS2ICLX is able to lower system-level power consumption to extend the operation of battery-powered nodes. The sensor's inherent characteristics simplify integration into high-performing products, while minimizing the effort and cost of calibration. Using MEMS accelerometer technology, the IIS2ICLX has a selectable full scale of 0.5/ 1/ 2/ 3g and provides outputs over an I2C or SPI digital interface.
Whitening and second order optimization both destroy information about the dataset, and can make generalization impossible
Wadia, Neha S., Duckworth, Daniel, Schoenholz, Samuel S., Dyer, Ethan, Sohl-Dickstein, Jascha
Machine learning is predicated on the concept of generalization: a model achieving low error on a sufficiently large training set should also perform well on novel samples from the same distribution. We show that both data whitening and second order optimization can harm or entirely prevent generalization. In general, model training harnesses information contained in the sample-sample second moment matrix of a dataset. For a general class of models, namely models with a fully connected first layer, we prove that the information contained in this matrix is the only information which can be used to generalize. Models trained using whitened data, or with certain second order optimization schemes, have less access to this information; in the high dimensional regime they have no access at all, producing models that generalize poorly or not at all. We experimentally verify these predictions for several architectures, and further demonstrate that generalization continues to be harmed even when theoretical requirements are relaxed. However, we also show experimentally that regularized second order optimization can provide a practical tradeoff, where training is still accelerated but less information is lost, and generalization can in some circumstances even improve.
$k$-means on Positive Definite Matrices, and an Application to Clustering in Radar Image Sequences
Fryer, Daniel, Nguyen, Hien, Castellazzi, Pascal
However, performing k-means on SPD matrices may correspond bijectively to mean centered Gaussian distributions, be difficult, without a computationally efficient form for the and are used to model Brownian motion in Diffusion Frรฉchet mean [13]. Tensor Imaging (DTI), where they are referred to as tensors [1]. The finite-lag autocovariance matrices of time-series are In Section II, we introduce the log-Cholesky distance and SPD, and have been used in compression based clustering closed-form expression for the corresponding Frรฉchet mean.
Researchers use artificial intelligence to strengthen power grid resilience
The US power grid system is not only large but dynamic, which makes it especially challenging to manage. Human operators know how to maintain systems when conditions are static. But when conditions change quickly operators lack a clear way of anticipating how the system should best adapt to meet system security and safety requirements. At the US Department of Energy's (DOE) Argonne National Laboratory a research team has developed a novel approach to help system operators understand how to better control power systems with the help of artificial intelligence. Their new approach could help operators control power systems in a more effective way, which could enhance the resilience of America's power grid, according to a recent article in IEEE Transactions on Power Systems.
ATM Cash demand forecasting in an Indian Bank with chaos and deep learning
Vangala, Sarveswararao, Vadlamani, Ravi
This paper proposes to model chaos in the ATM cash withdrawal time series of a big Indian bank and forecast the withdrawals using deep learning methods. It also considers the importance of day-of-the-week and includes it as a dummy exogenous variable. We first modelled the chaos present in the withdrawal time series by reconstructing the state space of each series using the lag, and embedding dimension found using an auto-correlation function and Cao's method. This process converts the uni-variate time series into multi variate time series. The "day-of-the-week" is converted into seven features with the help of one-hot encoding. Then these seven features are augmented to the multivariate time series. For forecasting the future cash withdrawals, using algorithms namely ARIMA, random forest (RF), support vector regressor (SVR), multi-layer perceptron (MLP), group method of data handling (GMDH), general regression neural network (GRNN), long short term memory neural network and 1-dimensional convolutional neural network. We considered a daily cash withdrawals data set from an Indian commercial bank. After modelling chaos and adding exogenous features to the data set, we observed improvements in the forecasting for all models. Even though the random forest (RF) yielded better Symmetric Mean Absolute Percentage Error (SMAPE) value, deep learning algorithms, namely LSTM and 1D CNN, showed similar performance compared to RF, based on t-test.
ScrewNet: Category-Independent Articulation Model Estimation From Depth Images Using Screw Theory
Jain, Ajinkya, Lioutikov, Rudolf, Niekum, Scott
Robots in human environments will need to interact with a wide variety of articulated objects such as cabinets, drawers, and dishwashers while assisting humans in performing day-to-day tasks. Existing methods either require objects to be textured or need to know the articulation model category a priori for estimating the model parameters for an articulated object. We propose ScrewNet, a novel approach that estimates an object's articulation model directly from depth images without requiring a priori knowledge of the articulation model category. ScrewNet uses screw theory to unify the representation of different articulation types and perform category-independent articulation model estimation. We evaluate our approach on two benchmarking datasets and compare its performance with a current state-of-the-art method. Results demonstrate that ScrewNet can successfully estimate the articulation models and their parameters for novel objects across articulation model categories with better on average accuracy than the prior state-of-the-art method.
Variable selection for Gaussian process regression through a sparse projection
Park, Chiwoo, Borth, David J., Wilson, Nicholas S., Hunter, Chad N.
This paper presents a new variable selection approach integrated with Gaussian process (GP) regression. We consider a sparse projection of input variables and a general stationary covariance model that depends on the Euclidean distance between the projected features. The sparse projection matrix is considered as an unknown parameter. We propose a forward stagewise approach with embedded gradient descent steps to co-optimize the parameter with other covariance parameters based on the maximization of a non-convex marginal likelihood function with a concave sparsity penalty, and some convergence properties of the algorithm are provided. The proposed model covers a broader class of stationary covariance functions than the existing automatic relevance determination approaches, and the solution approach is more computationally feasible than the existing MCMC sampling procedures for the automatic relevance parameter estimation with a sparsity prior. The approach is evaluated for a large number of simulated scenarios. The choice of tuning parameters and the accuracy of the parameter estimation are evaluated with the simulation study. In the comparison to some chosen benchmark approaches, the proposed approach has provided a better accuracy in the variable selection. It is applied to an important problem of identifying environmental factors that affect an atmospheric corrosion of metal alloys.
Counterfactual Explanations for Machine Learning on Multivariate Time Series Data
Ates, Emre, Aksar, Burak, Leung, Vitus J., Coskun, Ayse K.
Applying machine learning (ML) on multivariate time series data has growing popularity in many application domains, including in computer system management. For example, recent high performance computing (HPC) research proposes a variety of ML frameworks that use system telemetry data in the form of multivariate time series so as to detect performance variations, perform intelligent scheduling or node allocation, and improve system security. Common barriers for adoption for these ML frameworks include the lack of user trust and the difficulty of debugging. These barriers need to be overcome to enable the widespread adoption of ML frameworks in production systems. To address this challenge, this paper proposes a novel explainability technique for providing counterfactual explanations for supervised ML frameworks that use multivariate time series data. The proposed method outperforms state-of-the-art explainability methods on several different ML frameworks and data sets in metrics such as faithfulness and robustness. The paper also demonstrates how the proposed method can be used to debug ML frameworks and gain a better understanding of HPC system telemetry data.
Model Generalization in Deep Learning Applications for Land Cover Mapping
Hu, Lucas, Robinson, Caleb, Dilkina, Bistra
Recent work has shown that deep learning models can be used to classify land-use data from geospatial satellite imagery. We show that when these deep learning models are trained on data from specific continents/seasons, there is a high degree of variability in model performance on out-of-sample continents/seasons. This suggests that just because a model accurately predicts land-use classes in one continent or season does not mean that the model will accurately predict land-use classes in a different continent or season. We then use clustering techniques on satellite imagery from different continents to visualize the differences in landscapes that make geospatial generalization particularly difficult, and summarize our takeaways for future satellite imagery-related applications.
How COVID-19 is accelerating the shift away from fossil fuels
Creative destruction "is the essential fact about capitalism," wrote the great Austrian economist Joseph Schumpeter in 1942. New technologies and processes continuously revolutionize the economic structure from within, "incessantly destroying the old one, incessantly creating a new one." Change happens more quickly and creatively during times of economic disruption. Innovations meeting material and cultural needs accelerate. Structures preventing new, more efficient technologies weaken.