Confidence voting method ensemble applied to off-line signature verification

In this paper, a new approximation to off-line signature verification is proposed based on two-class classifiers using an expert decisions ensemble. Different methods to extract sets of local and a global features from the target sample are detailed. Also a normalization by confidence voting method is used in order to decrease the final equal error rate (EER). Each set of features is processed by a single expert, and on the other approach proposed, the decisions of the individual classifiers are combined using weighted votes. Experimental results are given using a subcorpus of the large MCYT signature database for random and skilled forgeries. The results show that the weighted combination outperforms the individual classifiers significantly. The best EER obtained were 6.3 % in the case of skilled forgeries and 2.31 % in the case of random forgeries.     

Towards practical anisotropic adaptive FEM on triangular meshes: a new refinement paradigm

Adaptive anisotropic refinement of finite element meshes allows one to reduce the computational effort required to achieve a specified accuracy of the solution of a PDE problem. We present a new approach to adaptive refinement and demonstrate that this allows one to construct algorithms which generate very flexible and efficient anisotropically refined meshes, even improving the convergence order compared to adaptive isotropic refinement if the problem permits.     

Model-based testing of software and systems: recent advances and challenges

Model-based testing is focused on testing techniques which rely on the use of models. The diversity of systems and software to be tested implies the need for research on a variety of models and methods for test automation. We briefly review this research area and introduce several papers selected from the 22nd International Conference on Testing Software and Systems (ICTSS).     

The GPU on the simulation of cellular computing models

Membrane Computing is a discipline aiming to abstract formal computing models, called membrane systems or P systems, from the structure and functioning of the living cells as well as from the cooperation of cells in tissues, organs, and other higher order structures. This framework provides polynomial time solutions to NP-complete problems by trading space for time, and whose efficient simulation poses challenges in three different aspects: an intrinsic massively parallelism of P systems, an exponential computational workspace, and a non-intensive floating point nature. In this paper, we analyze the simulation of a family of recognizer P systems with active membranes that solves the Satisfiability problem in linear time on different instances of Graphics Processing Units (GPUs). For an efficient handling of the exponential workspace created by the P systems computation, we enable different data policies to increase memory bandwidth and exploit data locality through tiling and dynamic queues. Parallelism inherent to the target P system is also managed to demonstrate that GPUs offer a valid alternative for high-performance computing at a considerably lower cost. Furthermore, scalability is demonstrated on the way to the largest problem size we were able to run, and considering the new hardware generation from Nvidia, Fermi, for a total speed-up exceeding four orders of magnitude when running our simulations on the Tesla S2050 server.     

Risk in Transport Investments

We discuss how the standard Cost-Benefit Analysis should be modified in order to take risk (and uncertainty) into account. We propose different approaches used in finance (Value at Risk, Conditional Value at Risk, Downside Risk Measures, and Efficiency Ratio) as useful tools to model the impact of risk in project evaluation. After introducing the concepts, we show how they could be used in CBA and provide some simple examples to illustrate how such concepts can be applied to evaluate the desirability of a new project infrastructure.     

A microbiological survey of fresh meat in the supermarket trade. Part 2: beef retail cuts

An assessment was made of the microbiological quality of the final product (different retail cuts), produced by two different retail supermarket groups (A & B). The influence of sanitary conditions on the microbiological quality of the final product was evaluated, and the possible influences on shelf life were determined. Supermarket group A (Sup group A) received carcasses with significantly lower surface counts of micro-organisms than supermarket group B (Sup group B), while the latter had a more efficient overall sanitation programme than supermarket group A. Five cuts were monitored for the presence of total aerobic counts, psychrotrophic counts, lactobacilli, Enterobacteriaceae and numbers of Pseudomonadaceae present. A shelf life study was also executed by repeating these enumerations on the same meat samples after refrigerated storage at 5°C for 2 and 4 days, respectively. It is generally accepted that a good refrigeration or chilling regime will preserve the inherent meat quality, but in this study it was found that neither served as a guarantee of quality. The more stringent hygiene at retail level of Sup group B yielded consistently lower mean counts of the different bacterial groups for all the meat cuts monitored and, thus meat with an extended shelf life. The total count (at 30°C) on meat cuts was the highest, followed by the psychrotrophs, the Pseudomonadaceae the Enterobacteriaeae and the lactobacilli. Minced meat generally had the highest mean aerobic total microbial counts. This count on minced meat might be a suitable indicator for monitoring the overall sanitary condition of a retail premises. The results re-emphasized the multi-factorial complexity of fresh meat quality and shelf life. The microbial quality of the raw material (carcasses), the maintenance of the cold chain, sanitary condition of premises, equipment and personnel surfaces and general management practices are factors that collectively determine the microbiological quality of the product.     

The influence of different centralised pre-packaging systems on the shelf-life of fresh pork

The influence of different centralised pre-packaging systems (PVC, modified atmosphere packaging (MAP), 25% CO(2) and 75% O(2), vacuum skin packaging (VSP) and the mother bag concept, 100% CO(2)) on the shelf-life (0, 7, 14 and 21 days at 0°C) of fresh pork was determined using microbiological, colour, odour and acceptability characteristics. All the packaging treatments were equally efficient for the first 4 days of retail display. In the extended shelf-life study (7, 14 and 21 days) the mother bag centralised packaging system gave the most promising shelf-life results (21 days) and was also judged superior in terms of odour. Modified atmosphere packaging (14 days) and VSP (7 days) may be considered as other possible options.     

Operator stress and monitoring practices

This study attempted to identify the major sources of work-related stress among telephone operators, with special emphasis on computer monitoring and telephone surveillance. A cross-sectional random sample of over 700 telephone operators participated in a questionnaire survey (response rate = 88%). The survey included items designed to measure perceived stress, management practices, specific job stressors and monitoring preferences. Call-time pressure items were most strongly linked to job stress by operators, with 70% reporting that difficulty in serving a customer well and still keeping call-time down contributed to their feelings of stress to a large or very large extent. About 55% of operators reported that telephone monitoring contributed to their feelings of job stress. If given the opportunity, 44% of operators stated they would prefer not to be monitored by telephone at all, while 23% stated they would prefer some monitoring; 33% had no preference. The setting of inappropriate individual-call-time objectives, which may be consistently unachievable for some operators and which create conflict between management demands for quantity and quality and also between workers values concerning quality and productivity demands, appears to be the most stress-inducing aspect of the job. In terms of telephone surveillance, the issues of timeliness and specificity of feedback appear to be less important than call-time pressure.     

Differentiation of Cancer Stem Cells by Using Synthetic Small Molecules: Toward New Therapeutic Strategies against Therapy Resistance

Despite the existing arsenal of anti-cancer drugs, 10 million people die each year worldwide due to cancers; this highlights the need to discover new therapies based on innovative modes of action against these pathologies. Current chemotherapies are based on the use of cytotoxic agents, targeted drugs, monoclonal antibodies or immunotherapies that are able to reduce or stop the proliferation of cancer cells. However, tumor eradication is often hampered by the presence of resistant cells called cancer stem-like cells or cancer stem cells (CSCs). Several strategies have been proposed to specifically target CSCs such as the use of CSC-specific antibodies, small molecules able to target CSC signaling pathways or drugs able to induce CSC differentiation rendering them sensitive to classical chemotherapy. These latter compounds are the focus of the present review, which aims to report recent advances in anticancer-differentiation strategies. This therapeutic approach was shown to be particularly promising for eradicating tumors in which CSCs are the main reason for therapeutic failure. This general view of the chemistry and mechanism of action of compounds inducing the differentiation of CSCs could be particularly useful for a broad range of researchers working in the field of anticancer therapies as the combination of compounds that induce differentiation with classical chemotherapy could represent a successful approach for future therapeutic applications.