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Weak Detection in the Spiked Wigner Model with General Rank

arXiv.org Machine Learning

We study the statistical decision process of detecting the presence of signal from a 'signal+noise' type matrix model with an additive Wigner noise. We derive the error of the likelihood ratio test, which minimizes the sum of the Type-I and Type-II errors, under the Gaussian noise for the signal matrix with arbitrary finite rank. We propose a hypothesis test based on the linear spectral statistics of the data matrix, which is optimal and does not depend on the distribution of the signal or the noise. We also introduce a test for rank estimation that does not require the prior information on the rank of the signal.


Human-like Time Series Summaries via Trend Utility Estimation

arXiv.org Machine Learning

In many scenarios, humans prefer a text-based representation of quantitative data over numerical, tabular, or graphical representations. The attractiveness of textual summaries for complex data has inspired research on data-to-text systems. While there are several data-to-text tools for time series, few of them try to mimic how humans summarize for time series. In this paper, we propose a model to create human-like text descriptions for time series. Our system finds patterns in time series data and ranks these patterns based on empirical observations of human behavior using utility estimation. Our proposed utility estimation model is a Bayesian network capturing interdependencies between different patterns. We describe the learning steps for this network and introduce baselines along with their performance for each step. The output of our system is a natural language description of time series that attempts to match a human's summary of the same data.


Adaptive Gradient Sparsification for Efficient Federated Learning: An Online Learning Approach

arXiv.org Machine Learning

--Federated learning (FL) is an emerging technique for training machine learning models using geographically dispersed data collected by local entities. It includes local computation and synchronization steps. T o reduce the communication overhead and improve the overall efficiency of FL, gradient sparsification (GS) can be applied, where instead of the full gradient, only a small subset of important elements of the gradient is communicated. Existing work on GS uses a fixed degree of gradient sparsity for i.i.d.-distributed data within a datacenter . In this paper, we consider adaptive degree of sparsity and non-i.i.d. We first present a fairness-aware GS method which ensures that different clients provide a similar amount of updates. Then, with the goal of minimizing the overall training time, we propose a novel online learning formulation and algorithm for automatically determining the near-optimal communication and computation tradeoff that is controlled by the degree of gradient sparsity. The online learning algorithm uses an estimated sign of the derivative of the objective function, which gives a regret bound that is asymptotically equal to the case where exact derivative is available. Experiments with real datasets confirm the benefits of our proposed approaches, showing up to 40% improvement in model accuracy for a finite training time. Modern consumer and enterprise users generate a large amount of data at the network edge, such as sensor measurements from Internet of Things (IoT) devices, images captured by cameras, transaction records of different branches of a company, etc. Such data may not be shareable with a central cloud, due to data privacy regulations and communication bandwidth limitation [1]. In these scenarios, federated learning (FL) is a useful approach for training machine learning models from local data [1]-[5]. The basic process of FL includes local gradient computation at clients and model weight (parameter) aggregation through a server. Instead of sharing the raw data, only model weights or gradients need to be shared between the clients and the server in the FL process.


Information Newton's flow: second-order optimization method in probability space

arXiv.org Machine Learning

We introduce a framework for Newton's flows in probability space with information metrics, named information Newton's flows. Here two information metrics are considered, including both the Fisher-Rao metric and the Wasserstein-2 metric. Several examples of information Newton's flows for learning objective/loss functions are provided, such as Kullback-Leibler (KL) divergence, Maximum mean discrepancy (MMD), and cross entropy. The asymptotic convergence results of proposed Newton's methods are provided. A known fact is that overdamped Langevin dynamics correspond to Wasserstein gradient flows of KL divergence. Extending this fact to Wasserstein Newton's flows of KL divergence, we derive Newton's Langevin dynamics. We provide examples of Newton's Langevin dynamics in both one-dimensional space and Gaussian families. For the numerical implementation, we design sampling efficient variational methods to approximate Wasserstein Newton's directions. Several numerical examples in Gaussian families and Bayesian logistic regression are shown to demonstrate the effectiveness of the proposed method.


Explainable Deep Convolutional Candlestick Learner

arXiv.org Machine Learning

Candlesticks are graphical representations of price movements for a given period. Although deep convolutional neural networks have achieved great success for recognizing the candlestick patterns, their reasoning hides inside a black box. The traders cannot make sure what the model has learned. In this contribution, we provide a framework which is to explain the reasoning of the learned model determining the specific candlestick patterns of time series. Based on the local search adversarial attacks, we show that the learned model perceives the pattern of the candlesticks in a way similar to the human trader.


Competence Assessment as an Expert System for Human Resource Management: A Mathematical Approach

arXiv.org Artificial Intelligence

Efficient human resource management needs accurate assessment and representation of available competences as well as effective mapping of required competences for specific jobs and positions. In this regard, appropriate definition and identification of competence gaps express differences between acquired and required competences. Using a detailed quantification scheme together with a mathematical approach is a way to support accurate competence analytics, which can be applied in a wide variety of sectors and fields. This article describes the combined use of software technologies and mathematical and statistical methods for assessing and analyzing competences in human resource information systems. Based on a standard competence model, which is called a Professional, Innovative and Social competence tree, the proposed framework offers flexible tools to experts in real enterprise environments, either for evaluation of employees towards an optimal job assignment and vocational training or for recruitment processes. The system has been tested with real human resource data sets in the frame of the European project called ComProFITS.


Knowledge Integration of Collaborative Product Design Using Cloud Computing Infrastructure

arXiv.org Artificial Intelligence

-- T he pivotal key for the success of manufacturing enterprises is sustainable and innovative product design and development. In collaborative design, stakehol ders are heterogeneously distributed chain - like . Due to the growing volume of data and knowledge, an effective management of the knowledge acquired in the product design and development is one of the key challenges facing most manufacturing enterprises. Opportunities for improving efficiency and performance of IT - based product design applications through centralization of resources such as knowledge and computation have increased in the last few years with maturation of technologies such as SOA, virtualization, grid computing, and /or cloud computing. The main focus of this paper is the concept of ongoing research in providing the knowledge integration service for collaborative product design and development using cloud computing infra structure . P otential s of the cloud computing to support the Knowledge integration functionalities as a Service by providing functionalities such as knowledge mapping, merging, searching, and transferring in product design procedure are described in this paper . Proposed knowledge integration services support users by giving real - time access to knowledge resources. The framework has the advantage of availability, efficiency, cost reduction, less time to result, and scalability . Changes made during the early design stage do not cause the significant increase in costs, while during the production stage, sharp increase in costs will occur since many blueprints, design documents or components would require re - work and re - design [ 5 ] . Today's research is focused on optimising the development methodologies to enable shorter time, lower costs and higher quality of the systems [ 2 ] . The pivotal key for the success of manufacturing enterprises is sustainable and innovative product design and development . In order to achieve this goal, it is required to have a real and deep knowledge of former and current procedures in the manufacturing enterprise [4] and future needs as well as customer feedback s and various stages of production cha in activities. Realization of an efficient knowledge transfer between different stakeholders of product development process such as linking customers and suppliers proactively throughout the entire value chain, and collaborating across boundaries in distri buted enterprise s is reinforcing this trend.


Practical Approach of Knowledge Management in Medical Science

arXiv.org Artificial Intelligence

Knowledge organization, infrastructure, and knowledge-based activities are all subjects that help in the creation of business strategies for the new enterprise. In this paper, the first basics of knowledge-based systems are studied. Practical issues and challenges of Knowledge Management (KM) implementations are then illustrated. Finally, a comparison of different knowledge-based projects is presented along with abstracted information on their implementation, techniques, and results. Most of these projects are in the field of medical science. Based on our study and evaluation of different KM projects, we conclude that KM is being used in every science, industry, and business. But its importance in medical science and assisted living projects are highlighted nowadays with the most of research institutes. Most medical centers are interested in using knowledge-based services like portals and learning techniques of knowledge for their future innovations and supports.


Optimal by Design: Model-Driven Synthesis of Adaptation Strategies for Autonomous Systems

arXiv.org Artificial Intelligence

--Many software systems have become too large and complex to be managed efficiently by human administrators, particularly when they operate in uncertain and dynamic environments and require frequent changes. Requirements-driven adaptation techniques have been proposed to endow systems with the necessary means to autonomously decide ways to satisfy their requirements. However, many current approaches rely on general-purpose languages, models and/or frameworks to design, develop and analyze autonomous systems. Unfortunately, these tools are not tailored towards the characteristics of adaptation problems in autonomous systems. D proposes a model (and a language) for the high-level description of the basic elements of self-adaptive systems, namely the system, capabilities, requirements and environment. Based on those elements, a Markov Decision Process (MDP) is constructed to compute the optimal strategy or the most rewarding system behavior . Furthermore, this defines a reflex controller that can ensure timely responses to changes. One novel feature of the framework is that it benefits both from goal-oriented techniques, developed for requirement elicitation, refinement and analysis, and synthesis capabilities and extensive research around MDPs, their extensions and tools. Our preliminary evaluation results demonstrate the practicality and advantages of the framework. Autonomous systems such as unmanned vehicles and robots play an increasingly relevant role in our societies. Many factors contribute to the complexity in the design and development of those systems. First, they typically operate in dynamic and uncontrollable environments [1]-[5]. Therefore, they must continuously adapt their configuration in response to changes, both in their operating environment and in themselves. Since the frequency of change cannot be controlled, decision-making must be almost instantaneous to ensure timely responses. From a design and management perspective, it is desirable to minimize the effort needed to design the system and to enable its runtime updating and maintenance. A promising technique to address those challenges is requirements-driven adaptation that endow systems with the necessary means to autonomously operate based on their requirements. Requirements are prescriptive statements of intent to be satisfied by cooperation of the agents forming the system [6]. They say what the system will do and not how it will do it [7].


Engineering AI Systems: A Research Agenda

arXiv.org Artificial Intelligence

Deploying machine-, and in particular deep-learning, (ML/DL) solutions in industry-strength, production quality contexts proves to challenging. This requires a structured engineering approach to constructing and evolving systems that contain ML/DL components. In this paper, we provide a conceptualization of the typical evolution patterns that companies experience when employing ML/DL well as a framework for integrating ML/DL components in systems consisting of multiple types of components. In addition, we provide an overview of the engineering challenges surrounding AI/ML/DL solutions and, based on that, we provide a research agenda and overview of open items that need to be addressed by the research community at large.