Statistical Learning
Dimensionality Reduction: Machine Learning with Python - sena Course
Become a Data Scientist expert! Everything you need to get the job you want! "Dimensionality Reduction: Machine Learning with Python" is likely a guide or tutorial that focuses on the topic of dimensionality reduction in the context of machine learning. In machine learning, dimensionality reduction is the process of reducing the number of features in a dataset while preserving as much of the important information as possible. This is often necessary because high-dimensional datasets can be difficult to work with, and can lead to problems such as overfitting and increased computational complexity. This guide likely covers these techniques with some implementation of these techniques using python libraries like numpy, scikit-learn and matplotlib .
Linear regression in detail. Linear regression is a statistical…
Linear regression is a statistical method for modeling the relationship between a dependent variable and one or more independent variables. It is a widely-used technique for predicting the outcome of a continuous variable, and it is especially useful when you have a large amount of data. In this blog post, we will discuss the theory behind linear regression, how to perform it in practice, and some of its applications. The basic idea behind linear regression is to find a line that best fits a set of data points. The line is represented by the equation y mx b, where y is the dependent variable, x is the independent variable, m is the slope of the line, and b is the y-intercept.
Step-by-Step Guide to Overcoming the Sparsity Challenge in Machine Learning Datasets
Sparse datasets are a common problem in machine learning, where many examples have a large number of missing or zero-valued features. This can lead to poor model performance and reduced interpretability of the results. In this article, we will provide a step-by-step guide on how to address the sparsity challenge in datasets, with a focus on real-world application. The first step in resolving the sparsity challenge is to understand why your dataset is sparse in the first place. Sparsity can be caused by the presence of irrelevant features, missing data, or categorical variables with a large number of levels.
AGMN: Association Graph-based Graph Matching Network for Coronary Artery Semantic Labeling on Invasive Coronary Angiograms
Zhao, Chen, Xu, Zhihui, Jiang, Jingfeng, Esposito, Michele, Pienta, Drew, Hung, Guang-Uei, Zhou, Weihua
Mailing address: 1400 Townsend Dr, Houghton, MI 49931 Abstract Semantic labeling of coronary arterial segments in invasive coronary angiography (ICA) is important for automated assessment and report generation of coronary artery stenosis in the computer-aided diagnosis of coronary artery disease (CAD). However, separating and identifying individual coronary arterial segments is challenging because morphological similarities of different branches on the coronary arterial tree and human-to-human variabilities exist. Inspired by the training procedure of interventional cardiologists for interpreting the structure of coronary arteries, we propose an association graph-based graph matching network (AGMN) for coronary arterial semantic labeling. We first extract the vascular tree from invasive coronary angiography (ICA) and convert it into multiple individual graphs. Then, an association graph is constructed from two individual graphs where each vertex represents the relationship between two arterial segments. Thus, we convert the arterial segment labeling task into a vertex classification task; ultimately, the semantic artery labeling becomes equivalent to identifying the artery-to-artery correspondence on graphs. More specifically, using the association graph, the AGMN extracts the vertex features by the embedding module, aggregates the features from adjacent vertices and edges by graph convolution network, and decodes the features to generate the semantic mappings between arteries. By learning the mapping of arterial branches between two individual graphs, the unlabeled arterial segments are classified by the labeled segments to achieve semantic labeling. A dataset containing 263 ICAs was employed to train and validate the proposed model, and a five-fold cross-validation scheme was performed. Our AGMN model achieved an average accuracy of 0.8264, an average precision of 0.8276, an average recall of 0.8264, and an average F1-score of 0.8262, which significantly outperformed existing coronary artery semantic labeling methods. In conclusion, we have developed and validated a new algorithm with high accuracy, interpretability, and robustness for coronary artery semantic labeling on ICAs. Keywords: coronary artery disease, invasive coronary angiography, coronary arterial anatomy, semantic labeling, graph matching network 1. Introduction Coronary artery disease (CAD), caused by narrowing or blockages of the coronary arteries, is the most common cardiovascular disease in the United States [1,2]. The narrowing is due to the buildup of fatty plaque along the artery walls, composed of cholesterol, lipids, and fibrous tissue [3]. If one or more of these arteries become severely obstructed, thereby reducing downstream blood flow, this may have the deleterious consequence of resulting in myocardial ischemia or infarction [4].
Fast conformational clustering of extensive molecular dynamics simulation data
Hunkler, Simon, Diederichs, Kay, Kukharenko, Oleksandra, Peter, Christine
We present an unsupervised data processing workflow that is specifically designed to obtain a fast conformational clustering of long molecular dynamics simulation trajectories. In this approach we combine two dimensionality reduction algorithms (cc\_analysis and encodermap) with a density-based spatial clustering algorithm (HDBSCAN). The proposed scheme benefits from the strengths of the three algorithms while avoiding most of the drawbacks of the individual methods. Here the cc\_analysis algorithm is for the first time applied to molecular simulation data. Encodermap complements cc\_analysis by providing an efficient way to process and assign large amounts of data to clusters. The main goal of the procedure is to maximize the number of assigned frames of a given trajectory, while keeping a clear conformational identity of the clusters that are found. In practice we achieve this by using an iterative clustering approach and a tunable root-mean-square-deviation-based criterion in the final cluster assignment. This allows to find clusters of different densities as well as different degrees of structural identity. With the help of four test systems we illustrate the capability and performance of this clustering workflow: wild-type and thermostable mutant of the Trp-cage protein (TC5b and TC10b), NTL9 and Protein B. Each of these systems poses individual challenges to the scheme, which in total give a nice overview of the advantages, as well as potential difficulties that can arise when using the proposed method.
Benign Overfitting in Time Series Linear Model with Over-Parameterization
Nakakita, Shogo, Imaizumi, Masaaki
The success of large-scale models in recent years has increased the importance of statistical models with numerous parameters. Several studies have analyzed over-parameterized linear models with high-dimensional data that may not be sparse; however, existing results depend on the independent setting of samples. In this study, we analyze a linear regression model with dependent time series data under over-parameterization settings. We consider an estimator via interpolation and developed a theory for the excess risk of the estimator. Then, we derive bounds of risks by the estimator for the cases where the temporal correlation of each coordinate of dependent data is homogeneous and heterogeneous, respectively. The derived bounds reveal that a temporal covariance of the data plays a key role; its strength affects the bias of the risk, and its nondegeneracy affects the variance of the risk. Moreover, for the heterogeneous correlation case, we show that the convergence rate of risks with short-memory processes is identical to that of cases with independent data, and the risk can converge to zero even with long-memory processes. Our theory can be extended to infinite-dimensional data in a unified manner. We also present several examples of specific dependent processes that can be applied to our setting.
Action Dynamics Task Graphs for Learning Plannable Representations of Procedural Tasks
Mao, Weichao, Desai, Ruta, Iuzzolino, Michael Louis, Kamra, Nitin
ADTG focuses solely on actions and avoids representing states in the graph, thereby making the size of the graph With the advent of augmented reality and advanced visionpowered much smaller than typical task graph representations. It uses AI systems, we envision a future of next generation robust visual representations of actions learnt by treating actions AI assistants that will be able to deeply understand the athome as "transformations between states". We also present tasks that users are doing from visual data and assist an approach to learn: (i) task tracking and (ii) next action them to accomplish these tasks. These AI assistants with reasoning prediction models based on ADTG using video demonstrations capabilities would be able to track the user's actions and paired action annotations of a procedural task. in an ongoing complex task, detect mistakes, and provide actionable guidance to the users such as next steps to take. Our approach allows us to observe users while they perform Such user-centric guidance can either help the user better procedural tasks and generate actionable plans for perform a task or help them learn a new task more efficiently.
Variational Inference: Posterior Threshold Improves Network Clustering Accuracy in Sparse Regimes
Variational inference has been widely used in machine learning literature to fit various Bayesian models. In network analysis, this method has been successfully applied to solve the community detection problems. Although these results are promising, their theoretical support is only for relatively dense networks, an assumption that may not hold for real networks. In addition, it has been shown recently that the variational loss surface has many saddle points, which may severely affect its performance, especially when applied to sparse networks. This paper proposes a simple way to improve the variational inference method by hard thresholding the posterior of the community assignment after each iteration. Using a random initialization that correlates with the true community assignment, we show that the proposed method converges and can accurately recover the true community labels, even when the average node degree of the network is bounded. Extensive numerical study further confirms the advantage of the proposed method over the classical variational inference and another state-of-the-art algorithm.
Factors other than climate change are currently more important in predicting how well fruit farms are doing financially
Obster, Fabian, Bohle, Heidi, Pechan, Paul M.
Machine learning and statistical modeling methods were used to analyze the impact of climate change on financial wellbeing of fruit farmers in Tunisia and Chile. The analysis was based on face to face interviews with 801 farmers. Three research questions were investigated. First, whether climate change impacts had an effect on how well the farm was doing financially. Second, if climate change was not influential, what factors were important for predicting financial wellbeing of the farm. And third, ascertain whether observed effects on the financial wellbeing of the farm were a result of interactions between predictor variables. This is the first report directly comparing climate change with other factors potentially impacting financial wellbeing of farms. Certain climate change factors, namely increases in temperature and reductions in precipitation, can regionally impact self-perceived financial wellbeing of fruit farmers. Specifically, increases in temperature and reduction in precipitation can have a measurable negative impact on the financial wellbeing of farms in Chile. This effect is less pronounced in Tunisia. Climate impact differences were observed within Chile but not in Tunisia. However, climate change is only of minor importance for predicting farm financial wellbeing, especially for farms already doing financially well. Factors that are more important, mainly in Tunisia, included trust in information sources and prior farm ownership. Other important factors include farm size, water management systems used and diversity of fruit crops grown. Moreover, some of the important factors identified differed between farms doing and not doing well financially. Interactions between factors may improve or worsen farm financial wellbeing.
Inverse Quantum Fourier Transform Inspired Algorithm for Unsupervised Image Segmentation
Akinola, Taoreed, Li, Xiangfang, Wilkins, Richard, Obiomon, Pamela, Qian, Lijun
Image segmentation is a very popular and important task in computer vision. In this paper, inverse quantum Fourier transform (IQFT) for image segmentation has been explored and a novel IQFT-inspired algorithm is proposed and implemented by leveraging the underlying mathematical structure of the IQFT. Specifically, the proposed method takes advantage of the phase information of the pixels in the image by encoding the pixels' intensity into qubit relative phases and applying IQFT to classify the pixels into different segments automatically and efficiently. To the best of our knowledge, this is the first attempt of using IQFT for unsupervised image segmentation. The proposed method has low computational cost comparing to the deep learning-based methods and more importantly it does not require training, thus make it suitable for real-time applications. The performance of the proposed method is compared with K-means and Otsu-thresholding. The proposed method outperforms both of them on the PASCAL VOC 2012 segmentation benchmark and the xVIEW2 challenge dataset by as much as 50% in terms of mean Intersection-Over-Union (mIOU).