A Genetic Programming Problem Definition Language Code Generator for the EpochX Framework

There are many different genetic programming (GP) frameworks that can be used to implement algorithms to solve a particular optimization problem. In order to use a framework, users need to become familiar with a large numbers of source code before actually implementing the algorithm, adding a learning overhead. In some cases, this can prevent users from trying out different frameworks. This paper discusses the implementation of a code generator in the EpochX framework to facilitate the implementation of GP algorithms. The code generator is based on the GP defini- tion language (GPDL), which is a framework-independent language that can be used to specify GP problems

A new sequential covering strategy for inducing classification rules with ant colony algorithms

Ant colony optimization (ACO) algorithms have been successfully applied to discover a list of classification rules. In general, these algorithms follow a sequential covering strategy, where a single rule is discovered at each iteration of the algorithm in order to build a list of rules. The sequential covering strategy has the drawback of not coping with the problem of rule interaction, i.e., the outcome of a rule affects the rules that can be discovered subsequently since the search space is modified due to the removal of examples covered by previous rules. This paper proposes a new sequential covering strategy for ACO classification algorithms to mitigate the problem of rule interaction, where the order of the rules is implicitly encoded as pheromone values and the search is guided by the quality of a candidate list of rules. Our experiments using 18 publicly available data sets show that the predictive accuracy obtained by a new ACO classification algorithm implementing the proposed sequential covering strategy is statistically significantly higher than the predictive accuracy of state-of-the-art rule induction classification algorithms

Event-based graphical monitoring in the EpochX genetic programming framework

EpochX is a genetic programming framework with provision for event management – similar to the Java event model – allowing the notification of particular actions during the lifecycle of the evolutionary algorithm. It also provides a flexible Stats system to gather statistics measures. This paper introduces a graphical interface to the EpochX genetic programming framework, taking full advantage of EpochX's event management. A set of representation-independent and tree-dependent GUI components are presented, showing how statistic information can be presented in a rich format using the information provided by EpochX's Stats system

A mathematically assisted reconstruction of the initial focus of the yellow fever outbreak in Buenos Aires (1871)

We discuss the historic mortality record corresponding to the initial focus of the yellow fever epidemic outbreak registered in Buenos Aires during the year 1871 as compared to simulations of a stochastic population dynamics model. This model incorporates the biology of the urban vector of yellow fever, the mosquito Aedes aegypti, the stages of the disease in the human being as well as the spatial extension of the epidemic outbreak. After introducing the historical context and the restrictions it puts on initial conditions and ecological parameters, we discuss the general features of the simulation and the dependence on initial conditions and available sites for breeding the vector. We discuss the sensitivity, to the free parameters, of statistical estimators such as: final death toll, day of the year when the outbreak reached half the total mortality and the normalized daily mortality, showing some striking regularities. The model is precise and accurate enough to discuss the truthfulness of the presently accepted historic discussions of the epidemic causes, showing that there are more likely scenarios for the historic facts.Comment: 25 pages, 12 figure

Non-parametric Estimation of Stochastic Differential Equations with Sparse Gaussian Processes

The application of Stochastic Differential Equations (SDEs) to the analysis of temporal data has attracted increasing attention, due to their ability to describe complex dynamics with physically interpretable equations. In this paper, we introduce a non-parametric method for estimating the drift and diffusion terms of SDEs from a densely observed discrete time series. The use of Gaussian processes as priors permits working directly in a function-space view and thus the inference takes place directly in this space. To cope with the computational complexity that requires the use of Gaussian processes, a sparse Gaussian process approximation is provided. This approximation permits the efficient computation of predictions for the drift and diffusion terms by using a distribution over a small subset of pseudo-samples. The proposed method has been validated using both simulated data and real data from economy and paleoclimatology. The application of the method to real data demonstrates its ability to capture the behaviour of complex systems

Evolving Recursive Programs using Non-recursive Scaffolding

Genetic programming has proven capable of evolving solutions to a wide variety of problems. However, the successes have largely been with programs without iteration or recursion; evolving recursive programs has turned out to be particularly challenging. The main obstacle to evolving recursive programs seems to be that they are particularly fragile to the application of search operators: a small change in a correct recursive program generally produces a completely wrong program. In this paper, we present a simple and general method that allows us to pass back and forth from a recursive program to an associated non-recursive program. Finding a recursive program can be reduced to evolving non-recursive programs followed by converting the optimum non-recursive program found to the associated optimum recursive program. This avoids the fragility problem above, as evolution does not search the space of recursive programs. We present promising experimental results on a test-bed of recursive problems

First observation of single-top-quark production

This paper reports the first observation of the electroweak production of single top quarks in p¯p collisions at a center-of-mass energy of 1.96TeV based on 2.3 fb−1 and 3.2 fb−1 of data collected by the DØ and CDF detectors, respectively, at the Fermilab Tevatron Collider. Using various multivariate techniques to separete the small signal from the large backgrounds, both experiments obtained a significance of the observed data of 5.0 standard deviations. DØ measures σ(p¯p → tb + X, tqb + X) = 3.94 ± 0.88 pb and CDF measures 2.3+0.6−0.5 pb. The CKM matrix element that couples the top and the bottom quarks is also measured. DØ reports |Vtb| > 0.78 at 95%CL when f1L = 1 and |Vtbf1L| = 1.02 ± 0.12. CDF measures |Vtb| = 0.91±0.11(stat+syst)±0.07(theory) and sets the limit |Vtb| > 0.71 at 95% CL

Procedures in the biochemical estimation of age of vertebrates

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147143/1/pope0152.pd

Creeping and structural effects in Faradaic artificial muscles

Reliable polymeric motors are required for the construction of rising accurate robots for surgeon assistance. Artificial muscles based on the electrochemistry of conducting polymers fulfil most of the required characteristics, except the presence of creeping effects during actuation. To avoid it, or to control it, a deeper knowledge of its physicochemical origin is required. With this aim here bending bilayer tape/PPy-DBSH (Polypyrrole-dodecylbenzylsulphonic acid) full polymeric artificial muscles were cycled between −2.5 and 1 V in aqueous solutions with parallel video recording of the described angular movement. Coulo-voltammetric (charge-potential, QE), dynamo-voltammetric (angle-potential, αE), and coulo-dynamic (charge-angle, Qα) muscular responses corroborate that 10 % of the charge is consumed by irreversible reactions overlapping the polymer reduction at the most cathodic potentials. In parallel, the range of the bending angular movement (145°) shifts by 15° per cycle (creeping effect) pointing to the irreversible charge as possible origin of the irreversible swelling of the PPy-DBS film. Different slopes in the closed loop part of the QE identify the different reaction driven structural processes in the film: oxidation-shrinking, oxidation compaction, reduction-relaxation, reduction-swelling, and reduction-vesicle’s formation. Despite the irreversible charge fraction, the muscle motor keeps a Faradaic behaviour: described angles are linear functions of the consumed charge in the full potential range