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Artificial intelligence in clinical research of cancers

#artificialintelligence

As a result, AI excels at handling large volumes and complex data, and identifying characteristic from the data, which the human brain cannot recognize. Although AI has been rapidly incorporated into oncologic research, the development of AI solutions is still in its infancy. Only a few AI-based applications have been approved for use in practice, e.g.


Machine Learning for Zombies

#artificialintelligence

Multilayer Perceptrons (MLP), are complex algorithms that take a lot of compute power and a *ton* of data in order to produce satisfactory results in reasonable timeframes. Let's start with what they're not: neural networks, despite the name and every blog post and intro to machine learning text book you've probably read up till now, are not analogs of the human brain. There are some *very* surface-level similarities, but the actual functionality of a neural network has almost nothing in common with the way the neurons that make up the approximately three pounds of meat that sits between your ears and defines everything you do and how you experience reality. Just like a lot of other machine learning algorithms, they use the formula "label equals weight times data value plus offset" (or y w*x b) to define where they draw their lines/hyperplanes for making predictions. In machine learning, that slope is called a weight.)


Simple Explanation to Machine Learning Ensemble concept

#artificialintelligence

I have been always a fan of using analogies and learning examples instead of complicated statistics and math functions in order to understand a concept in Machine learning. That's being said let's look at this situation. You just bought a new football club. Your new football club does not have any players and there are already 3 teams in the league. Team A has conceded 0 goals all seasons thus it is concluded that Team A has the best defense mechanism.


The Future of AI: How Can Model Developers Keep Up?

#artificialintelligence

With 83% of businesses noting that AI is something that they want to prioritize in the coming years, it's unsurprising that demand for data scientists is currently through the roof.[1] Indeed, Google alone requires 30,000 people to work on their machine learning models, showcasing just how much the job market is shifting in favor of programmers.[2] Based on this information, creators may be wondering what the future of machine learning holds for them. It becomes a bit of a minefield out there when technological advancements are outpacing what most people can keep track of. We'd say that preparedness usually yields the best results for algorithm creators, as it allows them to better assess datasets and make necessary adjustments to models over time. So, to make your life as an AI developer easier and keep you on the right path, we've compiled a list of the most important trends to consider when it comes to the future of machine learning.


Extensive Guide to Support Vector Machines - inovex GmbH

#artificialintelligence

Support vector machines (SVMs) are supervised machine learning models. They are the most prominent member of the class of kernel methods. SVMs can be used both for classification and regression. The original SVM proposed in 1963 is a simple binary linear classifier. Special to SVMs is that they use not any hyperplane but the one that maximizes the distance between itself and the two sets of datapoints.


Detect & Reject for Transferability of Black-box Adversarial Attacks Against Network Intrusion Detection Systems

arXiv.org Artificial Intelligence

In the last decade, the use of Machine Learning techniques in anomaly-based intrusion detection systems has seen much success. However, recent studies have shown that Machine learning in general and deep learning specifically are vulnerable to adversarial attacks where the attacker attempts to fool models by supplying deceptive input. Research in computer vision, where this vulnerability was first discovered, has shown that adversarial images designed to fool a specific model can deceive other machine learning models. In this paper, we investigate the transferability of adversarial network traffic against multiple machine learning-based intrusion detection systems. Furthermore, we analyze the robustness of the ensemble intrusion detection system, which is notorious for its better accuracy compared to a single model, against the transferability of adversarial attacks. Finally, we examine Detect & Reject as a defensive mechanism to limit the effect of the transferability property of adversarial network traffic against machine learning-based intrusion detection systems.


Class-aware Sounding Objects Localization via Audiovisual Correspondence

arXiv.org Artificial Intelligence

Audiovisual scenes are pervasive in our daily life. It is commonplace for humans to discriminatively localize different sounding objects but quite challenging for machines to achieve class-aware sounding objects localization without category annotations, i.e., localizing the sounding object and recognizing its category. To address this problem, we propose a two-stage step-by-step learning framework to localize and recognize sounding objects in complex audiovisual scenarios using only the correspondence between audio and vision. First, we propose to determine the sounding area via coarse-grained audiovisual correspondence in the single source cases. Then visual features in the sounding area are leveraged as candidate object representations to establish a category-representation object dictionary for expressive visual character extraction. We generate class-aware object localization maps in cocktail-party scenarios and use audiovisual correspondence to suppress silent areas by referring to this dictionary. Finally, we employ category-level audiovisual consistency as the supervision to achieve fine-grained audio and sounding object distribution alignment. Experiments on both realistic and synthesized videos show that our model is superior in localizing and recognizing objects as well as filtering out silent ones. We also transfer the learned audiovisual network into the unsupervised object detection task, obtaining reasonable performance.


Model Selection in Batch Policy Optimization

arXiv.org Machine Learning

We study the problem of model selection in batch policy optimization: given a fixed, partial-feedback dataset and $M$ model classes, learn a policy with performance that is competitive with the policy derived from the best model class. We formalize the problem in the contextual bandit setting with linear model classes by identifying three sources of error that any model selection algorithm should optimally trade-off in order to be competitive: (1) approximation error, (2) statistical complexity, and (3) coverage. The first two sources are common in model selection for supervised learning, where optimally trading-off these properties is well-studied. In contrast, the third source is unique to batch policy optimization and is due to dataset shift inherent to the setting. We first show that no batch policy optimization algorithm can achieve a guarantee addressing all three simultaneously, revealing a stark contrast between difficulties in batch policy optimization and the positive results available in supervised learning. Despite this negative result, we show that relaxing any one of the three error sources enables the design of algorithms achieving near-oracle inequalities for the remaining two. We conclude with experiments demonstrating the efficacy of these algorithms.


Selective Multiple Power Iteration: from Tensor PCA to gradient-based exploration of landscapes

arXiv.org Machine Learning

We propose Selective Multiple Power Iterations (SMPI), a new algorithm to address the important Tensor PCA problem that consists in recovering a spike $\bf{v_0}^{\otimes k}$ corrupted by a Gaussian noise tensor $\bf{Z} \in (\mathbb{R}^n)^{\otimes k}$ such that $\bf{T}=\sqrt{n} \beta \bf{v_0}^{\otimes k} + \bf{Z}$ where $\beta$ is the signal-to-noise ratio (SNR). SMPI consists in generating a polynomial number of random initializations, performing a polynomial number of symmetrized tensor power iterations on each initialization, then selecting the one that maximizes $\langle \bf{T}, \bf{v}^{\otimes k} \rangle$. Various numerical simulations for $k=3$ in the conventionally considered range $n \leq 1000$ show that the experimental performances of SMPI improve drastically upon existent algorithms and becomes comparable to the theoretical optimal recovery. We show that these unexpected performances are due to a powerful mechanism in which the noise plays a key role for the signal recovery and that takes place at low $\beta$. Furthermore, this mechanism results from five essential features of SMPI that distinguish it from previous algorithms based on power iteration. These remarkable results may have strong impact on both practical and theoretical applications of Tensor PCA. (i) We provide a variant of this algorithm to tackle low-rank CP tensor decomposition. These proposed algorithms also outperforms existent methods even on real data which shows a huge potential impact for practical applications. (ii) We present new theoretical insights on the behavior of SMPI and gradient descent methods for the optimization in high-dimensional non-convex landscapes that are present in various machine learning problems. (iii) We expect that these results may help the discussion concerning the existence of the conjectured statistical-algorithmic gap.


Surrogate Likelihoods for Variational Annealed Importance Sampling

arXiv.org Machine Learning

Variational inference is a powerful paradigm for approximate Bayesian inference with a number of appealing properties, including support for model learning and data subsampling. By contrast MCMC methods like Hamiltonian Monte Carlo do not share these properties but remain attractive since, contrary to parametric methods, MCMC is asymptotically unbiased. For these reasons researchers have sought to combine the strengths of both classes of algorithms, with recent approaches coming closer to realizing this vision in practice. However, supporting data subsampling in these hybrid methods can be a challenge, a shortcoming that we address by introducing a surrogate likelihood that can be learned jointly with other variational parameters. We argue theoretically that the resulting algorithm permits the user to make an intuitive trade-off between inference fidelity and computational cost. In an extensive empirical comparison we show that our method performs well in practice and that it is well-suited for black-box inference in probabilistic programming frameworks.