Boosting support vector machines for imbalanced data sets

Real world data mining applications must address the issue of learning from imbalanced data sets. The problem occurs when the number of instances in one class greatly outnumbers the number of instances in the other class. Such data sets often cause a default classifier to be built due to skewed vector spaces or lack of information. Common approaches for dealing with the class imbalance problem involve modifying the data distribution or modifying the classifier. In this work, we choose to use a combination of both approaches. We use support vector machines with soft margins as the base classifier to solve the skewed vector spaces problem. We then counter the excessive bias introduced by this approach with a boosting algorithm. We found that this ensemble of SVMs makes an impressive improvement in prediction performance, not only for the majority class, but also for the minority class.     

A survey of models and algorithms for winter road maintenance. Part IV: Vehicle routing and fleet sizing for plowing and snow disposal

This is the last part of a four-part survey of optimization models and solution algorithms for winter road maintenance planning. The two first parts of the survey address system design problems for winter road maintenance. The third part concentrates mainly on vehicle routing problems for spreading operations. The aim of this paper is to provide a comprehensive survey of optimization models and solution methodologies for the routing of vehicles for plowing and snow disposal operations. We also review models for the fleet sizing and fleet replacement problems.     

Impact of high pressure treatment on the structure of montmorillonite

The modification of sodium montmorillonite after a high pressure pasteurization treatment was followed by X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis. Regardless of the treatment intensity (300 and 800 MPa), the structure of montmorillonite was clearly modified. Such changes should be taken into consideration when binging montmorillonite–polymer nanocomposites into contact with food.     

Concomitant use of liquid–liquid batch and continuous plug flow reactors for kinetic model discrimination. Application to the Rh/TPPTS catalysed reduction of the C–C double bond in dimethylitaconate

The biphasic catalytic reduction of the C–C double bond of dimethylitaconate with a water soluble rhodium/triphenylphosphinetrisulphonated sodium salt (TPPTS) complex is investigated. Kinetic studies in a well-mixed batch reactor provide kinetics parameters and an activation energy of 71 kJ mol⁻¹ but cannot discriminate between a first order or a complex kinetic model within the range of substrate concentration where the approximation of linear liquid/liquid partition is respected. Catalytic tests in the centrifugal partition chromatograph (CPC) reactor under steady-state operations in chemical regime and plug flow mode allow discriminating the kinetic models, the complex kinetic rate law being preferred.     

Cold Compaction and Solid-State Sintering of WC-Co-Based Structures: Experiments and Modeling

Cold compaction (200-1900 MPa) and sintering (1250°-1350°C) of cermets based on WC-Co were experimentally studied using die compaction, cold isostatic pressing, sintering, and creep tests. Two different-sized WC powders were used. The cobalt content varied over a range of 10-30 wt%. Cold-compaction behavior has been described by using a Cam-Clay model. Die-wall friction was measured by using green powder compacts that had different aspect ratios. Friction coefficients were 0.28-0.85, depending on the WC particle size and cobalt content. Simple constitutive equations have been used to model the high-temperature behavior (sintering and creep). The constitutive equations were implemented in a finite-element program to model the compaction, ejection, and sintering of bilayer structures that had different cobalt contents. The model can represent the effect of die-wall friction on the average density, as well as deformation inside the green compact. Density gradients were generated; they were revealed during sintering, because the compact does not deform homogeneously. Simulation also can be used to evaluate deformations that are induced by sintering.     

Variable energy positron beam study of Xe-implanted uranium oxide

Doppler broadening of annihilation gamma-line combined with a slow positron beam was used to measure the momentum density distribution of annihilating pair in a set of sintered UO₂ samples. The influence of surface polishing, of implantation with 800-keV ¹³⁶Xe²⁺ at fluences of 1 × 10¹⁵ and 1 × 10¹⁶ Xe cm^?2, and of annealing were studied by following the changes of the momentum distribution shape by means of S and W parameters. The program used for this purpose was VEPFIT. At the two fluences in the stoichiometric as-implanted UO₂, formation of Xe bubbles was not detected. The post-implantation annealing and over-stoichiometry in the as-implanted sample caused Xe precipitation and formation of Xe bubbles.     

Tetrahydroindoles as Multipurpose Screening Compounds and Novel Sirtuin Inhibitors

Indoles are privileged structures in medicinal and bioorganic chemistry that are particularly well suited to serve as platforms for diversity. Among many other therapeutic areas, the indole scaffold has been used to design aromatic compounds useful to interfere with enzymes engaged in the regulation of substrate acylation status, such as sirtuins. However, the planarity of the indole ring is not necessarily optimal for all target enzymes, especially when functionalization with aromatic side chains is required. Replacement of flat scaffolds by nonplanar molecular cores dominated by sp³ hybridization is a common strategy to avoid the disadvantages associated with poor solubility and high promiscuity, while covering less-well-explored areas of chemical space. Thus, we synthesized fragment-like tetrahydroindoles suitable for fragment-based drug discovery as well as a well-characterized small library intended as multipurpose screening compounds. For proof of principle, these compounds were screened against sirtuins 1–3, enzymes known to be addressable by indoles. We found that 2,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indole-3-carboxamides are potent and selective SIRT2 inhibitors. Compound 16 t displayed an IC₅₀ value of 0.98 μm and could serve as exquisite starting point for hit-to-lead profiling.     

Anti-Inflammatory Effect of Very High Dose Local Vessel Wall Statin Administration: Poly(L,L-Lactide) Biodegradable Microspheres with Simvastatin for Drug Delivery System (DDS)

Atherosclerosis involves an ongoing inflammatory response of the vascular endothelium and vessel wall of the aorta and vein. The pleiotropic effects of statins have been well described in many in vitro and in vivo studies, but these effects are difficult to achieve in clinical practice due to the low bioavailability of statins and their first-pass metabolism in the liver. The aim of this study was to test a vessel wall local drug delivery system (DDS) using PLA microstructures loaded with simvastatin. Wistar rats were fed high cholesterol chow as a model. The rat vessels were chemically injured by repeated injections of perivascular paclitaxel and 5-fluorouracil. The vessels were then cultured and treated by the injection of several concentrations of poly(L,L-lactide) microparticles loaded with the high local HMG-CoA inhibitor simvastatin (0.58 mg/kg) concentration (SVPLA). Histopathological examinations of the harvested vessels and vital organs after 24 h, 7 days and 4 weeks were performed. Microcirculation in mice as an additional test was performed to demonstrate the safety of this approach. A single dose of SVPLA microspheres with an average diameter of 6.4 μm and a drug concentration equal to 8.1% of particles limited the inflammatory reaction of the endothelium and vessel wall and had no influence on microcirculation in vivo or in vitro. A potent pleiotropic (anti-inflammatory) effect of simvastatin after local SVPLA administration was observed. Moreover, significant concentrations of free simvastatin were observed in the vessel wall (compared to the maximum serum level). In addition, it appeared that simvastatin, once locally administered as SVPLA particles, exerted potent pleiotropic effects on chemically injured vessels and presented anti-inflammatory action. Presumably, this effect was due to the high local concentrations of simvastatin. No local or systemic side effects were observed. This approach could be useful for local simvastatin DDSs when high, local drug concentrations are difficult to obtain, or systemic side effects are present.     

Synthesis, Autoorganization and Reactivity of Amphiphilic Derivatives of 1-Aminoisoindole in Water and Formamide

In this work, we present the synthesis of cationic surfactants based on 1-aminoisoindole. The physico-chemical properties were studied by conductometry, tensiometry, dynamic light scattering and transmission electron microscopy in water and in formamide. The reactivity of these novel surfactants has been studied at concentrations below and above critical aggregation concentrations (CAC) and it was found that reactions can proceed in structured media without the addition of other catalysts.     

Understanding Interactive Legends: a Comparative Evaluation with Standard Widgets

Interactive information visualization systems rely on widgets to allow users to interact with the data and modify the representation. We define interactive legends as a class of controls combining the visual representation of static legends and interaction mechanisms of widgets. As interactive legends start to appear in popular websites, we categorize their designs for common data types and evaluate their effectiveness compare to standard widgets. Results suggest that 1) interactive legends can lead to faster perception of the mapping between data values and visual encodings and 2) interaction time is affected differently depending on the data type. Additionally, our study indicates superiority both in terms of perception and interaction of ordinal controls over numerical ones. Numerical techniques are mostly used in today's systems. By providing solutions to allowing users to modify ranges interactively, we believe that interactive legends make it possible to increase the use of ordinal techniques for visual exploration.