A dynamic overproduce-and-choose strategy for the selection of classifier ensembles

The overproduce-and-choose strategy, which is divided into the overproduction and selection phases, has traditionally focused on finding the most accurate subset of classifiers at the selection phase, and using it to predict the class of all the samples in the test data set. It is therefore, a static classifier ensemble selection strategy. In this paper, we propose a dynamic overproduce-and-choose strategy which combines optimization and dynamic selection in a two-level selection phase to allow the selection of the most confident subset of classifiers to label each test sample individually. The optimization level is intended to generate a population of highly accurate candidate classifier ensembles, while the dynamic selection level applies measures of confidence to reveal the candidate ensemble with the highest degree of confidence in the current decision. Experimental results conducted to compare the proposed method to a static overproduce-and-choose strategy and a classical dynamic classifier selection approach demonstrate that our method outperforms both these selection-based methods, and is also more efficient in terms of performance than combining the decisions of all classifiers in the initial pool.     

Adaptive ROC-based ensembles of HMMs applied to anomaly detection

Hidden Markov models (HMMs) have been successfully applied in many intrusion detection applications, including anomaly detection from sequences of operating system calls. In practice, anomaly detection systems (ADSs) based on HMMs typically generate false alarms because they are designed using limited amount of representative training data. Since new data may become available over time, an important feature of an ADS is the ability to accommodate newly acquired data incrementally, after it has originally been trained and deployed for operations. In this paper, a system based on the receiver operating characteristic (ROC) is proposed to efficiently adapt ensembles of HMMs (EoHMMs) in response to new data, according to a learn-and-combine approach. When a new block of training data becomes available, a pool of base HMMs is generated from the data using a different number of HMM states and random initializations. The responses from the newly trained HMMs are then combined to those of the previously trained HMMs in ROC space using a novel incremental Boolean combination (incrBC) technique. Finally, specialized algorithms for model management allow to select a diversified EoHMM from the pool, and adapt Boolean fusion functions and thresholds for improved performance, while it prunes redundant base HMMs. The proposed system is capable of changing the desired operating point during operations, and this point can be adjusted to changes in prior probabilities and costs of errors. Computer simulations conducted on synthetic and real-world host-based intrusion detection data indicate that the proposed system can achieve a significantly higher level of performance than when parameters of a single best HMM are estimated, at each learning stage, using reference batch and incremental learning techniques. It also outperforms the learn-and-combine approaches using static fusion functions (e.g., majority voting). Over time, the proposed ensemble selection algorithms form compact EoHMMs, while maintaining or improving system accuracy. Pruning allows to limit the pool size from increasing indefinitely, thereby reducing the storage space for accommodating HMMs parameters without negatively affecting the overall EoHMM performance. Although applied for HMM-based ADSs, the proposed approach is general and can be employed for a wide range of classifiers and detection applications.     

Questions éthiques en psychologie.

This book is the result of months of work by a small group interested in ethical debates surrounding diverse professional practices. The different chapters examine the relationships among ethics, morality, and psychology. Of special interest are ethical questions relating to the conduct of research; the use and interpretation of standardized tests, given issues of validity and reliability; and the problems of developing and transmitting expertise in psychological practice. The values of respect, liberty, and justice are seen as relevant and applicable to psychological practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Runoff of pharmaceuticals and personal care products following application of biosolids to an agricultural field

Municipal biosolids are a source of nutrients for crop production. Beneficial Management Practices (BMPs) can be used to minimize the risk of contamination of adjacent water resources with chemical or microbial agents that are of public or environmental health concern. In this field study, we applied biosolids slurry at a commercial rate using either subsurface injection or broadcast application followed by incorporation. Precipitation was simulated at 1, 3, 7, 22, 36 and 266 days post-application on 2 m² microplots to evaluate surface runoff of 9 model pharmaceuticals and personal care products (PPCPs), atenolol, carbamazepine, cotinine, gemfibrozil, naproxen, ibuprofen, acetaminophen, sulfamethoxazole and triclosan. In runoff from the injected plots, concentrations of the model PPCPs were generally below the limits of quantitation. In contrast, in the broadcast application treatment, the concentrations of atenolol, carbamazepine, cotinine, gemfibrozil, naproxen, sulfamethoxazole and triclosan on the day following application ranged from 70-1477 ng L^− 1 in runoff and generally declined thereafter with first order kinetics. The total mass of PPCPs mobilized in surface runoff per m² of the field ranged from 0.63 µg for atenolol to 21.1 µg for ibuprofen. For ibuprofen and acetaminophen, concentrations in runoff first decreased and then increased, suggesting that these drugs were initially chemically or physically sequestered in the biosolids slurry, and subsequently released in the soil. Carbamazepine and triclosan were detected at low concentrations in a runoff event 266 days after broadcast application. Overall, this study showed that injection of biosolids slurry below the soil surface could effectively eliminate surface runoff of PPCPs.     

Evaluation of incremental learning algorithms for HMM in the recognition of alphanumeric characters

We present an evaluation of incremental learning algorithms for the estimation of hidden Markov model (HMM) parameters. The main goal is to investigate incremental learning algorithms that can provide as good performances as traditional batch learning techniques, but incorporating the advantages of incremental learning for designing complex pattern recognition systems. Experiments on handwritten characters have shown that a proposed variant of the ensemble training algorithm, employing ensembles of HMMs, can lead to very promising performances. Furthermore, the use of a validation dataset demonstrated that it is possible to reach better performances than the ones presented by batch learning.     

Moving toward a global psychology: Changing theories and practice to meet the needs of a changing world.

Increasingly, the United States is becoming internationalized as a result of sophisticated communication technologies that put us in touch with countries known previously to only a few, through economic development and multinational investment, and by the immigration of people who are sometimes fleeing hostile homelands. US citizens, like others abroad, will need to be responsive to the demands of a multiethnic, multiracial, and multinational society. The challenges of this changing world can and will range from such dilemmas as ethical decisions of who can and will have access to expensive technology that saves and prolongs life; to the development of conflict management strategies for peaceful coexistence with neighbors whose behaviors, beliefs, and values are strongly shaped by their religious, cultural, and ethnic backgrounds and socioeconomic circumstances. With the inauguration of this section, US psychology is invited to consider its contribution to meeting the needs of a changing society. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Securing high resolution grayscale facial captures using a blockwise coevolutionary GA

In biometric systems, reference facial images captured during enrollment are commonly secured using watermarking, where invisible watermark bits are embedded into these images. Evolutionary Computation (EC) is widely used to optimize embedding parameters in intelligent watermarking (IW) systems. Traditional IW methods represent all blocks of a cover image as candidate embedding solutions of EC algorithms, and suffer from premature convergence when dealing with high resolution grayscale facial images. For instance, the dimensionality of the optimization problem to process a 2048 × 1536 pixel grayscale facial image that embeds 1 bit per 8 × 8 pixel block involves 49k variables represented with 293k binary bits. Such Large-Scale Global Optimization problems cannot be decomposed into smaller independent ones because watermarking metrics are calculated for the entire image. In this paper, a Blockwise Coevolutionary Genetic Algorithm (BCGA) is proposed for high dimensional IW optimization of embedding parameters of high resolution images. BCGA is based on the cooperative coevolution between different candidate solutions at the block level, using a local Block Watermarking Metric (BWM). It is characterized by a novel elitism mechanism that is driven by local blockwise metrics, where the blocks with higher BWM values are selected to form higher global fitness candidate solutions. The crossover and mutation operators of BCGA are performed on block level. Experimental results on PUT face image database indicate a 17% improvement of fitness produced by BCGA compared to classical GA. Due to improved exploration capabilities, BCGA convergence is reached in fewer generations indicating an optimization speedup.     

A semi‐discrete shell finite element for textile composite reinforcement forming simulation

A triangular shell element for the simulation of textile composite reinforcements forming is proposed. This element is made up of unit woven cells. The internal virtual works are added on all woven cells of the element. They depend on tensions, in‐plane shear and bending moments that are directly those given by the experimental tests that are specific to textile composite reinforcement. The element has only displacement degrees of freedom; the bending curvatures are obtained from the displacement of the neighbouring elements. A set of example shows the efficiency of the approach and the relative roles of the tensile, in‐plane shear and bending rigidities. Especially their influence on the appearance and the development of wrinkles in draping and forming tests is analysed. Copyright © 2009 John Wiley & Sons, Ltd.     

International psychology: Is the whole greater than the sum of its parts?

The beginning of international psychology dates back to the end of the 19th century, with the 1st International Congress held in Paris in 1889, but its first official structure, the International Union of Scientific Psychology, was created only in 1951. A rapid development then followed and today, 68 national societies of psychology involving more than one half billion psychologists throughout the world are currently represented by the Union, which has indeed become the voice of psychology on the international scene. The present structure of international psychology and its various elements are presented and discussed, and the role and function it assumes are described in relation to the development of psychology as a science and a profession. Examples are given of the capacity-building role to which international psychology has given priority and of diverse research projects pursued in collaboration with United Nations agencies, such as the United Nations Education Scientific and Cultural Organization (UNESCO) and World Health Organization. Current issues, such as the unity of psychology and the archiving of primary psychological data, are discussed, and future perspectives and directions are identified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)