Statistical Learning
SCENE: Reasoning about Traffic Scenes using Heterogeneous Graph Neural Networks
Monninger, Thomas, Schmidt, Julian, Rupprecht, Jan, Raba, David, Jordan, Julian, Frank, Daniel, Staab, Steffen, Dietmayer, Klaus
Abstract--Understanding traffic scenes requires considering heterogeneous information about dynamic agents and the static infrastructure. Task-specific decoders can be applied to predict desired attributes of the scene. To this end, the vehicle needs to correctly estimate which sensory information is reliable I. NDERSTANDING traffic scenes is important for an autonomous vehicle such that it may develop a safe, agents is conveyed by the perception systems of autonomous effective and efficient plan of how to move forward. We raise the hypothesis that considering additional instance, whether a stationary car is parked or just temporarily heterogeneous entities in a traffic scene might add valuable stopped determines whether the autonomous vehicle should information. In particular, reasoning should also involve wait or overtake. Understanding of traffic scenes requires knowledge about static infrastructure, which may either be reasoning about dynamic agents and static infrastructure in perceived or in our case is provided by a High Definition order to predict the intents of nearby dynamic agents (e.g., (HD) map.
Dynamic Tensor Product Regression
Reddy, Aravind, Song, Zhao, Zhang, Lichen
In this work, we initiate the study of \emph{Dynamic Tensor Product Regression}. One has matrices $A_1\in \mathbb{R}^{n_1\times d_1},\ldots,A_q\in \mathbb{R}^{n_q\times d_q}$ and a label vector $b\in \mathbb{R}^{n_1\ldots n_q}$, and the goal is to solve the regression problem with the design matrix $A$ being the tensor product of the matrices $A_1, A_2, \dots, A_q$ i.e. $\min_{x\in \mathbb{R}^{d_1\ldots d_q}}~\|(A_1\otimes \ldots\otimes A_q)x-b\|_2$. At each time step, one matrix $A_i$ receives a sparse change, and the goal is to maintain a sketch of the tensor product $A_1\otimes\ldots \otimes A_q$ so that the regression solution can be updated quickly. Recomputing the solution from scratch for each round is very slow and so it is important to develop algorithms which can quickly update the solution with the new design matrix. Our main result is a dynamic tree data structure where any update to a single matrix can be propagated quickly throughout the tree. We show that our data structure can be used to solve dynamic versions of not only Tensor Product Regression, but also Tensor Product Spline regression (which is a generalization of ridge regression) and for maintaining Low Rank Approximations for the tensor product.
Smart Application for Fall Detection Using Wearable ECG & Accelerometer Sensors
Timely and reliable detection of falls is a large and rapidly growing field of research due to the medical and financial demand of caring for a constantly growing elderly population. Within the past 2 decades, the availability of high-quality hardware (high-quality sensors and AI microchips) and software (machine learning algorithms) technologies has served as a catalyst for this research by giving developers the capabilities to develop such systems. This study developed multiple application components in order to investigate the development challenges and choices for fall detection systems, and provide materials for future research. The smart application developed using this methodology was validated by the results from fall detection modelling experiments and model mobile deployment. The best performing model overall was the ResNet152 on a standardised, and shuffled dataset with a 2s window size which achieved 92.8% AUC, 87.28% sensitivity, and 98.33% specificity. Given these results it is evident that accelerometer and ECG sensors are beneficial for fall detection, and allow for the discrimination between falls and other activities. This study leaves a significant amount of room for improvement due to weaknesses identified in the resultant dataset. These improvements include using a labelling protocol for the critical phase of a fall, increasing the number of dataset samples, improving the test subject representation, and experimenting with frequency domain preprocessing.
Privacy-Preserving Record Linkage for Cardinality Counting
Wu, Nan, Vatsalan, Dinusha, Kaafar, Mohamed Ali, Ramesh, Sanath Kumar
Several applications require counting the number of distinct items in the data, which is known as the cardinality counting problem. Example applications include health applications such as rare disease patients counting for adequate awareness and funding, and counting the number of cases of a new disease for outbreak detection, marketing applications such as counting the visibility reached for a new product, and cybersecurity applications such as tracking the number of unique views of social media posts. The data needed for the counting is however often personal and sensitive, and need to be processed using privacy-preserving techniques. The quality of data in different databases, for example typos, errors and variations, poses additional challenges for accurate cardinality estimation. While privacy-preserving cardinality counting has gained much attention in the recent times and a few privacy-preserving algorithms have been developed for cardinality estimation, no work has so far been done on privacy-preserving cardinality counting using record linkage techniques with fuzzy matching and provable privacy guarantees. We propose a novel privacy-preserving record linkage algorithm using unsupervised clustering techniques to link and count the cardinality of individuals in multiple datasets without compromising their privacy or identity. In addition, existing Elbow methods to find the optimal number of clusters as the cardinality are far from accurate as they do not take into account the purity and completeness of generated clusters. We propose a novel method to find the optimal number of clusters in unsupervised learning. Our experimental results on real and synthetic datasets are highly promising in terms of significantly smaller error rate of less than 0.1 with a privacy budget {\epsilon} = 1.0 compared to the state-of-the-art fuzzy matching and clustering method.
Fast and Correct Gradient-Based Optimisation for Probabilistic Programming via Smoothing
Khajwal, Basim, Ong, C. -H. Luke, Wagner, Dominik
We study the foundations of variational inference, which frames posterior inference as an optimisation problem, for probabilistic programming. The dominant approach for optimisation in practice is stochastic gradient descent. In particular, a variant using the so-called reparameterisation gradient estimator exhibits fast convergence in a traditional statistics setting. Unfortunately, discontinuities, which are readily expressible in programming languages, can compromise the correctness of this approach. We consider a simple (higher-order, probabilistic) programming language with conditionals, and we endow our language with both a measurable and a smoothed (approximate) value semantics. We present type systems which establish technical pre-conditions. Thus we can prove stochastic gradient descent with the reparameterisation gradient estimator to be correct when applied to the smoothed problem. Besides, we can solve the original problem up to any error tolerance by choosing an accuracy coefficient suitably. Empirically we demonstrate that our approach has a similar convergence as a key competitor, but is simpler, faster, and attains orders of magnitude reduction in work-normalised variance.
Scaling Laws for Generative Mixed-Modal Language Models
Aghajanyan, Armen, Yu, Lili, Conneau, Alexis, Hsu, Wei-Ning, Hambardzumyan, Karen, Zhang, Susan, Roller, Stephen, Goyal, Naman, Levy, Omer, Zettlemoyer, Luke
Generative language models define distributions over sequences of tokens that can represent essentially any combination of data modalities (e.g., any permutation of image tokens from VQ-VAEs, speech tokens from HuBERT, BPE tokens for language or code, and so on). To better understand the scaling properties of such mixed-modal models, we conducted over 250 experiments using seven different modalities and model sizes ranging from 8 million to 30 billion, trained on 5-100 billion tokens. We report new mixed-modal scaling laws that unify the contributions of individual modalities and the interactions between them. We also find four empirical phenomena observed during the training, such as emergent coordinate-ascent style training that naturally alternates between modalities, guidelines for selecting critical hyper-parameters, and connections between mixed-modal competition and training stability. Finally, we test our scaling law by training a 30B speechtext model, which significantly outperforms the corresponding unimodal models. Overall, our research provides valuable insights into the design and training of mixed-modal generative models, an important new class of unified models that have unique distributional properties. Generative language models have been developed for a wide range of data modalities, including natural language text Brown et al. (2020), code (Chen et al., 2021; Fried et al., 2022), images (Ramesh et al., 2021; Yasunaga et al., 2022), and molecules or proteins (Chilingaryan et al., 2022; Hsu et al., 2022). Recent work has also introduced unified models (Aghajanyan et al., 2022; Reed et al., 2022; Wang et al., 2022; Zellers et al., 2022) that can simultaneously model multiple modalities. One advantage of generative modeling in these cases is that the models scale well in practice; adding data, compute, or parameters typically improves model quality. These scaling trends have been carefully studied for uni-modal models (Kaplan et al., 2020; Hoffmann et al., 2022) and some recent work focuses on pairs of modalities (Droppo & Elibol, 2021; Henighan et al., 2020).
Progress in Manifold Learning part1(Machine Learning)
Abstract: Isomap algorithm is a representative manifold learning algorithm. The algorithm simplifies the data analysis process and is widely used in neuroimaging, spectral analysis and other fields. However, the classic Isomap algorithm becomes unwieldy when dealing with large data sets. Our object is to accelerate the classical algorithm with quantum computing, and propose the quantum Isomap algorithm. The algorithm consists of two sub-algorithms.
5 Growing Libraries in Python for Causality Analysis
At least in neuroscience, mainly 2 models have been mostly used (or abused): Granger causality and Dynamic causal modeling (DCM). Those are, at the same time, the Good, the Bad, and the Ugly. Granger causality (so called from its inventor) is based on the idea that if one time series (called the "predictor") has some predictive power for another time series (called the "predictand"), then past values of the predictor should contain information that can help forecast future values of the predictand. To test for Granger causality, researchers typically use statistical techniques such as regression analysis or vector autoregression (VAR) to estimate the strength of the relationship between the two-time series. If the predictor series is found to significantly improve the forecast of the predictand series, it is said to have Granger causality with respect to the predictand.
Machine learning modeling for the prediction of plastic properties in metallic glasses
Metallic glasses are one of the most interesting mechanical materials studied in the last years, but as amorphous solids, they differ strongly from their crystalline counterparts. This matter can be addressed with the development and application of predictive techniques capable to describe the plastic regime. Here, machine learning models were employed for the prediction of plastic properties in CuZr metallic glasses. To this aim, 100 different samples were subjected to tensile tests by means of molecular dynamics simulations. A total of 17 materials properties were calculated and explored using statistical analysis. Strong correlations were found for stoichiometry, temperature, structural, and elastic properties with plastic properties. Three regression models were employed for the prediction of six plastic properties. Linear and Ridge regressions delivered the better prediction capability, with coefficients of determination above $$\sim$$ 80% for three plastic properties, whereas Lasso regression rendered lower performance, with coefficients of determination above $$\sim$$ 60% for two plastic properties. Overall, our work shows that molecular dynamics simulations together with machine learning models can provide a framework for the prediction of plastic behavior of complex materials.
Generative Time Series Forecasting with Diffusion, Denoise, and Disentanglement
Li, Yan, Lu, Xinjiang, Wang, Yaqing, Dou, Dejing
Time series forecasting has been a widely explored task of great importance in many applications. However, it is common that real-world time series data are recorded in a short time period, which results in a big gap between the deep model and the limited and noisy time series. In this work, we propose to address the time series forecasting problem with generative modeling and propose a bidirectional variational auto-encoder (BVAE) equipped with diffusion, denoise, and disentanglement, namely D3VAE. Specifically, a coupled diffusion probabilistic model is proposed to augment the time series data without increasing the aleatoric uncertainty and implement a more tractable inference process with BVAE. To ensure the generated series move toward the true target, we further propose to adapt and integrate the multiscale denoising score matching into the diffusion process for time series forecasting. In addition, to enhance the interpretability and stability of the prediction, we treat the latent variable in a multivariate manner and disentangle them on top of minimizing total correlation. Extensive experiments on synthetic and real-world data show that D3VAE outperforms competitive algorithms with remarkable margins. Our implementation is available at https://github.com/PaddlePaddle/PaddleSpatial/tree/main/research/D3VAE.