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Entropy inference and the James-Stein estimator, with application to nonlinear gene association networks

arXiv.org Machine Learning

We present a procedure for effective estimation of entropy and mutual information from small-sample data, and apply it to the problem of inferring high-dimensional gene association networks. Specifically, we develop a James-Stein-type shrinkage estimator, resulting in a procedure that is highly efficient statistically as well as computationally. Despite its simplicity, we show that it outperforms eight other entropy estimation procedures across a diverse range of sampling scenarios and data-generating models, even in cases of severe undersampling. We illustrate the approach by analyzing E. coli gene expression data and computing an entropy-based gene-association network from gene expression data. A computer program is available that implements the proposed shrinkage estimator.


Empirical Bernstein Bounds and Sample Variance Penalization

arXiv.org Machine Learning

W e give improved constants for data dependent and variance sensitive confidence bounds, called empirical Bernstein bounds, and extend these inequalities to hold uniformly over classes of functions whose growth function is polynomial in the sample size n . The bounds lead us to consider sample variance penalization, a novel learning method which takes into account the empirical variance of the loss function. W e give conditions under which sample variance penalization is effective. In particular, we present a bound on the excess risk incurred by the method. Using this, we argue that there are situations in which the excess risk of our method is of order 1 /n, while the excess risk of empirical risk minimization is of order 1 / n . W e show some experimental results, which confirm the theory. Finally, we discuss the potential application of our results to sample compression schemes.


The Single Machine Total Weighted Tardiness Problem - Is it (for Metaheuristics) a Solved Problem ?

arXiv.org Artificial Intelligence

The article presents a study of rather simple local search heuristics for the single machine total weighted tardiness problem (SMTWTP), namely hillclimbing and Variable Neighborhood Search. In particular, we revisit these approaches for the SMTWTP as there appears to be a lack of appropriate/challenging benchmark instances in this case. The obtained results are impressive indeed. Only few instances remain unsolved, and even those are approximated within 1% of the optimal/best known solutions. Our experiments support the claim that metaheuristics for the SMTWTP are very likely to lead to good results, and that, before refining search strategies, more work must be done with regard to the proposition of benchmark data. Some recommendations for the construction of such data sets are derived from our investigations.


Developing an End-to-End Planning Application from a Timeline Representation Framework

AAAI Conferences

This paper describes aspects of a project aiming at creating general, flexible and reusable software architecture to address planning problems in space missions. It introduces recent work to realize an open software framework for supporting development of planning and scheduling space applications. The framework, which is named TRF (Timeline-based Representation Framework), aims at supporting application development within different space missions for the European Space Agency (ESA). It is currently being tested on three problem examples, all solved on top of the TRF functionalities. This paper describes the TRF three-layered software architecture and shows how it has been used to deploy a complete application, named MrSPOCK, an interactive system for Long Term Planning in the Mars Express operational mission.


Q-Strategy: Automated Bidding and Convergence in Computational Markets

AAAI Conferences

Agents and market mechanisms are widely elaborated and applied to automate interaction and decision processes among others in robotics, for decentralized control in sensor networks and by algorithmic traders in financial markets. Currently there is a high demand of efficient mechanisms for the provisioning, usage and allocation of distributed services in the Cloud. Such mechanisms and processes are not manually manageable and require decisions taken in quasi real-time. Thus agent decisions should automatically adapt to changing conditions and converge to optimal values. This paper presents a bidding strategy, which is capable of automating the bid generation and utility maximization processes of consumers and providers by the interaction with markets as well as to converge to optimal values. The bidding strategy is applied to the consumer side against benchmark bidding strategies and its behavior and convergence are evaluated in two market mechanisms, a centralized and a decentralized one.


Using AI to Solve Inspection Scheduling Problem for a Buying Office

AAAI Conferences

This paper presents a project awarded by MGB HK to handle their inspection scheduling problem. MGB HK is the buying office of one of the largest retailers in the world, Metro Group. MGB HK handles all product procurement of Metro Group out of Europe. The inspection process is one of their critical processes along their entire procurement exercise. The objective of this project is to provide an effective scheduling engine so that in-house inspectors can handle as many inspections as possible using the least amount of time and costs. Meanwhile, we also help the company overcome their difficulties of data collection and maintenance as a result of the system we developed. Our engine will be deployed and integrated into the company’s IMS. The engine recorded an improvement in the scheduling of their inspections and initial prognosis indicates that delayed inspections have been greatly reduced by compared with previous schedule. The system can effectively schedule inspections by urgency, shipment value, and supplier’s historical performance. Other than the schedule, the AI engine can also generate solutions based on different strategies and criteria, which facilitate the decision-making process for the scheduling team and management at MGB HK.


Automated Critique of Sketched Mechanisms

AAAI Conferences

Designers often use a series of sketches to explain how their design goes through different states or modes to achieve its intended function. Learning how to create such explanations turns out to be a difficult problem for engineering students. An automated "crash test dummy" to let students practice explanations would be desirable. This paper describes how to carry out a core piece of the reasoning needed in such system. We show how an open-domain sketch understanding system can be used to enter many aspects of such explanations, and how qualitative mechanics can be used to check the plausibility of the intended state transitions. The system is evaluated using a corpus of sketches based on designs from an engineering school design and communications course.


Hashigo: A Next-Generation Sketch Interactive System for Japanese Kanji

AAAI Conferences

Language students can increase their effectiveness in learning written Japanese by mastering the visual structure and written technique of Japanese kanji.  Yet, existing kanji handwriting recognition systems do not assess the written technique sufficiently enough to discourage students from developing bad learning habits.  In this paper, we describe our work on Hashigo, a kanji sketch interactive system which achieves human instructor-level critique and feedback on both the visual structure and written technique of students’ sketched kanji.  This type of automated critique and feedback allows students to target and correct specific deficiencies in their sketches that, if left untreated, are detrimental to effective long-term kanji learning.


Not So Naive Online Bayesian Spam Filter

AAAI Conferences

Spam filtering, as a key problem in electronic communication, has drawn significant attention due to increasingly huge amounts of junk email on the Internet. Content-based filtering is one reliable method in combating with spammers' changing tactics. Naive Bayes (NB) is one of the earliest content-based machine learning methods both in theory and practice in combating with spammers, which is easy to implement while can achieve considerable accuracy. In this paper, the traditional online Bayesian classifier are enhanced  by two ways. First, from theory's point of view, we devise a self-adaptive mechanism to gradually weaken the assumption of independence required by original NB in the online training process, and as a result of that our NSNB is no longer ``naive''. Second, we propose other engineering ways to make the classifier more robust and accuracy. The experiment results show that our NSNB does give state-of-the-art classification performance on online spam filtering on large benchmark data sets while it is extremely fast and takes up little memory in comparison with other statistical methods.


A Data-Mining Approach to 3D Realistic Render Setup Assistance

AAAI Conferences

Realistic rendering is the process of generating a 2D image from an abstract description of a 3D scene, aiming at achieving the quality of a photo. The quality of the generated image depends on the accuracy with which the employed render method simulates the behaviour of the light particles through the scene. According to the current practice, it is up to the user to choose optimal settings of input parameters for these methods in terms of time-efficiency, as well as image quality. This is an iterative trial and error process, even for expert users. This paper describes a novel approach based on techniques from the field of data mining and genetic computing to assist the user in the selection of render parameters. Experimental results are presented which show the benefits of this approach.