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Transformative Machine Learning

arXiv.org Machine Learning

The key to success in machine learning (ML) is the use of effective data representations. Traditionally, data representations were hand-crafted. Recently it has been demonstrated that, given sufficient data, deep neural networks can learn effective implicit representations from simple input representations. However, for most scientific problems, the use of deep learning is not appropriate as the amount of available data is limited, and/or the output models must be explainable. Nevertheless, many scientific problems do have significant amounts of data available on related tasks, which makes them amenable to multi-task learning, i.e. learning many related problems simultaneously. Here we propose a novel and general representation learning approach for multi-task learning that works successfully with small amounts of data. The fundamental new idea is to transform an input intrinsic data representation (i.e., handcrafted features), to an extrinsic representation based on what a pre-trained set of models predict about the examples. This transformation has the dual advantages of producing significantly more accurate predictions, and providing explainable models. To demonstrate the utility of this transformative learning approach, we have applied it to three real-world scientific problems: drug-design (quantitative structure activity relationship learning), predicting human gene expression (across different tissue types and drug treatments), and meta-learning for machine learning (predicting which machine learning methods work best for a given problem). In all three problems, transformative machine learning significantly outperforms the best intrinsic representation.


An Optimal Transport View on Generalization

arXiv.org Machine Learning

We derive upper bounds on the generalization error of learning algorithms based on their \emph{algorithmic transport cost}: the expected Wasserstein distance between the output hypothesis and the output hypothesis conditioned on an input example. The bounds provide a novel approach to study the generalization of learning algorithms from an optimal transport view and impose less constraints on the loss function, such as sub-gaussian or bounded. We further provide several upper bounds on the algorithmic transport cost in terms of total variation distance, relative entropy (or KL-divergence), and VC dimension, thus further bridging optimal transport theory and information theory with statistical learning theory. Moreover, we also study different conditions for loss functions under which the generalization error of a learning algorithm can be upper bounded by different probability metrics between distributions relating to the output hypothesis and/or the input data. Finally, under our established framework, we analyze the generalization in deep learning and conclude that the generalization error in deep neural networks (DNNs) decreases exponentially to zero as the number of layers increases. Our analyses of generalization error in deep learning mainly exploit the hierarchical structure in DNNs and the contraction property of $f$-divergence, which may be of independent interest in analyzing other learning models with hierarchical structure.


Internal Wiring of Cartesian Verbs and Prepositions

arXiv.org Artificial Intelligence

Categorical compositional distributional semantics (CCDS) allows one to compute the meaning of phrases and sentences from the meaning of their constituent words. A type-structure carried over from the traditional categorial model of grammar a la Lambek becomes a 'wire-structure' that mediates the interaction of word meanings. However, CCDS has a much richer logical structure than plain categorical semantics in that certain words can also be given an 'internal wiring' that either provides their entire meaning or reduces the size their meaning space. Previous examples of internal wiring include relative pronouns and intersective adjectives. Here we establish the same for a large class of well-behaved transitive verbs to which we refer as Cartesian verbs, and reduce the meaning space from a ternary tensor to a unary one. Some experimental evidence is also provided.


Unveiling Swarm Intelligence with Network Science$-$the Metaphor Explained

arXiv.org Artificial Intelligence

Self-organization is a natural phenomenon that emerges in systems with a large number of interacting components. Self-organized systems show robustness, scalability, and flexibility, which are essential properties when handling real-world problems. Swarm intelligence seeks to design nature-inspired algorithms with a high degree of self-organization. Yet, we do not know why swarm-based algorithms work well and neither we can compare the different approaches in the literature. The lack of a common framework capable of characterizing these several swarm-based algorithms, transcending their particularities, has led to a stream of publications inspired by different aspects of nature without much regard as to whether they are similar to already existing approaches. We address this gap by introducing a network-based framework$-$the interaction network$-$to examine computational swarm-based systems via the optics of social dynamics. We discuss the social dimension of several swarm classes and provide a case study of the Particle Swarm Optimization. The interaction network enables a better understanding of the plethora of approaches currently available by looking at them from a general perspective focusing on the structure of the social interactions.


Rotational Diversity in Multi-Cycle Assignment Problems

arXiv.org Artificial Intelligence

In multi-cycle assignment problems with rotational diversity, a set of tasks has to be repeatedly assigned to a set of agents. Over multiple cycles, the goal is to achieve a high diversity of assignments from tasks to agents. At the same time, the assignments' profit has to be maximized in each cycle. Due to changing availability of tasks and agents, planning ahead is infeasible and each cycle is an independent assignment problem but influenced by previous choices. We approach the multi-cycle assignment problem as a two-part problem: Profit maximization and rotation are combined into one objective value, and then solved as a General Assignment Problem. Rotational diversity is maintained with a single execution of the costly assignment model. Our simple, yet effective method is applicable to different domains and applications. Experiments show the applicability on a multi-cycle variant of the multiple knapsack problem and a real-world case study on the test case selection and assignment problem, an example from the software engineering domain, where test cases have to be distributed over compatible test machines.


Towards Compositional Distributional Discourse Analysis

arXiv.org Artificial Intelligence

In the last couple of decades, the traditional symbolic approach to AI and cognitive science -- which aims at characterising human intelligence in terms of abstract logical processes -- has been challenged by so-called connectionist AI: the study of the human brain as a complex network of basic processing units [18]. When it comes to human language, the same divide manifests itself as the opposition between two principles, which in turn induce two distinct approaches to Natural Language Processing (NLP). On one hand Frege's principle of compositionality asserts that the meaning of a complex expression is a function of its sub-expressions, and the way in which they are composed -- distributionality on the other hand can be summed up in Firth's maxim "You shall know a word by the company it keeps". Once implemented in terms of concrete algorithms we have expert systems driven by formal logical rules on one end, artificial neural networks and machine learning on the other. Categorical Compositional Distributional (DisCoCat) models, first introduced in [4], aim at getting the best of both worlds: the string diagrams notation borrowed from category theory allows to manipulate the grammatical reductions as linear maps, and compute graphically the semantics of a sentence as the composition of the vectors which we obtain from the distributional semantics of its constituent words. In this paper, we introduce basic anaphoric discourses as mid-level representations between natural language discourse on one end -- formalised in terms of basic discourse representation structures (DRS) [2]; and knowledge queries over the Semantic Web on the other -- given by basic graph patterns in the Resource Description Framework (RDF) [19]. We construct discourses as formal diagrams of real-valued matrices and we then use these diagrams to give abstract reformulations of NLP problems: probabilistic anaphora resolution and question answering.


Classical Copying versus Quantum Entanglement in Natural Language: The Case of VP-ellipsis

arXiv.org Artificial Intelligence

This paper compares classical copying and quantum entanglement in natural language by considering the case of verb phrase (VP) ellipsis. VP ellipsis is a non-linear linguistic phenomenon that requires the reuse of resources, making it the ideal test case for a comparative study of different copying behaviours in compositional models of natural language. Following the line of research in compositional distributional semantics set out by (Coecke et al., 2010) we develop an extension of the Lambek calculus which admits a controlled form of contraction to deal with the copying of linguistic resources. We then develop two different compositional models of distributional meaning for this calculus. In the first model, we follow the categorical approach of (Coecke et al., 2013) in which a functorial passage sends the proofs of the grammar to linear maps on vector spaces and we use Frobenius algebras to allow for copying. In the second case, we follow the more traditional approach that one finds in categorial grammars, whereby an intermediate step interprets proofs as non-linear lambda terms, using multiple variable occurrences that model classical copying. As a case study, we apply the models to derive different readings of ambiguous elliptical phrases and compare the analyses that each model provides.


Meet Furhat, the terrifying AI assistant with a face: Robot is trained to move and talk like a human

Daily Mail - Science & tech

A Stockholm-based startup has developed a talking AI assistant with a face. Furhat combines digital assistant technology akin to Alexa or Siri and humanoid robots like SoftBank's Pepper to create a device that's creepily lifelike. It's essentially a disembodied head that can be customized with different faces - even characters from the sci-fi film Avatar. Furhat is a social robot created by Stockholm-based startup Furhat Robotics. It weighs just over 7lbs and is essentially a disembodied head with a face projected onto it.


Theory proposed by Alan Turing explains the patterns of tooth-like scales found on sharks

Daily Mail - Science & tech

Tooth-like scales of sharks and chicken feathers are created by the same process and explained by a theory from the legendary code-breaker Alan Turing. His reaction-diffusion theory is widely accepted as the way in which many animals get unique patterns in their feathers, fur, teeth and teeth. It has now been extended to include the development of shark scales - a group of animals that are very distantly related to the other known animals. The findings help explain how the scales of a shark evolved to reduce drag and be more energy efficient while swimming. Scientists believe this patterning could help in designing shark-inspired materials to improve energy efficiency.


Self driving vehicles could lead to 'mobile brothels' that drive to client's houses

Daily Mail - Science & tech

Self driving cars are set to have a huge effect on commuters - but will also dramatically change other businesses, a new report has warned. Academics from the University of Surrey and the University of Oxford say the advent of autonomous vehicles will affect everything from red light districts in major cities to restaurants and hotels. They also warn of potential for terrorism facilitated by autonomous vehicles (AVs) also raises genuine security fears. A Waymo self-driving car is seen during the annual Google I/O developers conference in Mountain View. Academics from the University of Surrey and the University of Oxford say the advent of autonomous vehicles will affect a huge range of industries.