Evolutionary Multiobjective Optimization algorithm for multimedia delivery in critical applications through Content-Aware Networks

Critical applications which need to deliver multimedia through the Internet, may achieve the required quality of service thanks to the Content-Aware Networks (CAN). The key element of CAN is an efficient decision algorithm responsible for the selection of the best content source and routing paths for content delivery. This paper proposes a two-phase decision algorithm, exploiting the Evolutionary Multiobjective Optimization (EMO) approach. It allows to consider valid information in different time scales, adapting decision-maker to the evolving network and server conditions as well as to get the optimal solution in different shapes of Pareto front. The simulation experiments performed in a large-scale network model, confirm the effectiveness of the proposed two-phase EMO algorithm, comparing to other multi-criteria decision algorithms used in CAN.     

Generating operation specifications from UML class diagrams: A model transformation approach

One of the more tedious and complex tasks during the specification of conceptual schemas (CSs) is modeling the operations that define the system behavior. This paper aims to simplify this task by providing a method that automatically generates a set of basic operations that complement the static aspects of the CS and suffice to perform all typical life-cycle create/update/delete changes on the population of the elements of the CS. Our method guarantees that the generated operations are executable, i.e. their executions produce a consistent state wrt the most typical structural constraints that can be defined in CSs (e.g. multiplicity constraints). In particular, our method takes as input a CS expressed as a Unified Modeling Language (UML) class diagram (optionally defined using a profile to enrich the specification of associations) and generates an extended version of the CS that includes all necessary operations to start operating the system. If desired, these basic operations can be later used as building blocks for creating more complex ones. We show the formalization and implementation of our method by means of model-to-model transformations. Our approach is particularly relevant in the context of Model Driven Development approaches.     

Single crystals morphology of biodegradable double crystalline PLLA-b-PCL diblock copolymers

The morphology of solution grown single crystals of a series of double crystalline diblock copolymers derived from l-lactide and ?-caprolactone has been investigated by means of transmission electron microscopy. The copolymers had a variable composition with a poly(l-lactide) weight percentage that ranged between 81 and 10%. All samples had a low polydispersity index (1.4-1.1) and a similar number average molecular weight (20,000-35,000 g/mol).Bulk crystallization and melting behaviour of diblock copolymers were evaluated by DSC and the results demonstrated the double crystalline nature of the samples. Fractionated crystallization clearly occurred in copolymers having an intermediate composition.Isothermal crystallizations were performed in dilute n-hexanol solutions at temperatures that ranged between 80 and 50 °C. Crystal morphologies were dependent on the crystallization temperature and even on the composition. Thus, the inability of poly(?-caprolactone) (PCL) blocks to crystallize between 80 and 70 °C rendered lozenge, truncated and spindle-shaped crystals associated to the poly(l-lactide) (PLLA) block. These usually had thicker edges due to PLLA overgrowths that mainly took place in their periphery. However, an overgrowth of irregular PCL crystals during subsequent cooling and crystallization at room temperature was also detected. Complex morphologies constituted by lamellar crystals of both PCL and PLLA blocks were developed at intermediate temperatures (70-65 °C), whereas elongated hexagonal morphologies mainly associated to the PCL block were detected at the lowest crystallization temperature. In general, electron diffraction patterns showed for all samples’ reflections associated to both poly(?-caprolactone) and poly(l-lactide) (α-form) crystals. The relative intensity between the two types of reflections varied according to the copolymer composition.     

Design of a General‐Purpose European Compound Screening Library for EU‐OPENSCREEN

This work describes a collaborative effort to define and apply a protocol for the rational selection of a general‐purpose screening library, to be used by the screening platforms affiliated with the EU‐OPENSCREEN initiative. It is designed as a standard source of compounds for primary screening against novel biological targets, at the request of research partners. Given the general nature of the potential applications of this compound collection, the focus of the selection strategy lies on ensuring chemical stability, absence of reactive compounds, screening‐compliant physicochemical properties, loose compliance to drug‐likeness criteria (as drug design is a major, but not exclusive application), and maximal diversity/coverage of chemical space, aimed at providing hits for a wide spectrum of drugable targets. Finally, practical availability/cost issues cannot be avoided. The main goal of this publication is to inform potential future users of this library about its conception, sources, and characteristics. The outline of the selection procedure, notably of the filtering rules designed by a large committee of European medicinal chemists and chemoinformaticians, may be of general methodological interest for the screening/medicinal chemistry community. The selection task of 200K molecules out of a pre‐filtered set of 1.4M candidates was shared by five independent European research groups, each picking a subset of 40K compounds according to their own in‐house methodology and expertise. An in‐depth analysis of chemical space coverage of the library serves not only to characterize the collection, but also to compare the various chemoinformatics‐driven selection procedures of maximal diversity sets. Compound selections contributed by various participating groups were mapped onto general‐purpose self‐organizing maps (SOMs) built on the basis of marketed drugs and bioactive reference molecules. In this way, the occupancy of chemical space by the EU‐OPENSCREEN library could be directly compared with distributions of known bioactives of various classes. This mapping highlights the relevance of the selection and shows how the consensus reached by merging the five different 40K selections contributes to achieve this relevance. The approach also allows one to readily identify subsets of target‐ or target‐class‐oriented compounds from the EU‐OPENSCREEN library to suit the needs of the diverse range of potential users. The final EU‐OPENSCREEN library, assembled by merging five independent selections of 40K compounds from various expert groups, represents an excellent example of a Europe‐wide collaborative effort toward the common objective of building best‐in‐class European open screening platforms.     

Segmentation of multiple sclerosis lesions in brain MRI: A review of automated approaches

Automatic segmentation of multiple sclerosis (MS) lesions in brain MRI has been widely investigated in recent years with the goal of helping MS diagnosis and patient follow-up. However, the performance of most of the algorithms still falls far below expert expectations. In this paper, we review the main approaches to automated MS lesion segmentation. The main features of the segmentation algorithms are analysed and the most recent important techniques are classified into different strategies according to their main principle, pointing out their strengths and weaknesses and suggesting new research directions. A qualitative and quantitative comparison of the results of the approaches analysed is also presented. Finally, possible future approaches to MS lesion segmentation are discussed.     

Superparamagnetic Ag@Co‐Nanocomposites on Granulated Cation Exchange Polymeric Matrices with Enhanced Antibacterial Activity for the Environmentally Safe Purification of Water

Cation exchange polymeric matrices are widely used in water treatment protocols to reduce the mineral content of hard waters, even for human consumption. However, they are not antibacterial and flowing bacteria can be trapped in their structures and proliferate, thus acting as microbial contamination sources. Here, Ag@Co‐nanoparticles (Ag@Co‐NPs) with a low‐cost superparamagnetic Co⁰‐core and an antibacterial Ag‐shell are synthesized on granulated cation exchange polymeric matrices under soft reaction conditions. The presence of these NPs provides the final nanocomposite (NC) with additional functionalities (superparamagnetism and antibacterial activity) making it ideal for water purification applications. Ag@Co‐NPs are synthesized in situ on four cation exchange polymeric matrices containing either strong (sulfonic) or weak (carboxylic) acid functional groups homogeneously distributed (C‐type) or concentrated on an external shell (SST‐type) by the intermatrix synthesis (IMS) method. The NCs are characterized (metal content, NP size and distribution, metal oxidative state, and metal release) and evaluated for water purification applications.     

Reputation-based decisions for logic-based cognitive agents

Computational trust and reputation models have been recognized as one of the key technologies required to design and implement agent systems. These models manage and aggregate the information needed by agents to efficiently perform partner selection in uncertain situations. For simple applications, a game theoretical approach similar to that used in most models can suffice. However, if we want to undertake problems found in socially complex virtual societies, we need more sophisticated trust and reputation systems. In this context, reputation-based decisions that agents make take on special relevance and can be as important as the reputation model itself. In this paper, we propose a possible integration of a cognitive reputation model, Repage, into a cognitive BDI agent. First, we specify a belief logic capable to capture the semantics of Repage information, which encodes probabilities. This logic is defined by means of a two first-order languages hierarchy, allowing the specification of axioms as first-order theories. The belief logic integrates the information coming from Repage in terms if image and reputation, and combines them, defining a typology of agents depending of such combination. We use this logic to build a complete graded BDI model specified as a multi-context system where beliefs, desires, intentions and plans interact among each other to perform a BDI reasoning. We conclude the paper with an example and a related work section that compares our approach with current state-of-the-art models.     

Optimising by the response surface methodology the enzymatic elimination of clogging of a microfiltration membrane by pectin cake

The aim of this paper, in which clogging occurs on the filter at a constant vacuum pressure and constant pectin weight, is to find the optimal values of the variables, temperature and time, to know the best conditions to reduce this clogging by enzymatic hydrolysis. Moreover, different properties of the compression of the cake in the filter were determined such as the filtering medium total resistance (R_fT), bed porosity (ε) and the cake‐specific resistance (α) at different times and temperatures. The filter area was 0.142 m², and the value of the mass fraction of solids in the filtered suspension (S) was 0.12. Scanning electron microsopy (SEM) analyses were performed. The results showed that the compressive stress corresponding to the cake improves the flow rate in the filtration flux at the optimal temperature and time for the process, where the enzyme reaches its highest activity. The test results of this study can be applied in different system of filters during cross‐flow filtration.     

Synthesis of poly(ester amide)s composed of lactic acid and glycolic acid units by the bulk polycondensation of metal halide salts

Thermal polycondensation of the potassium salt of N‐methylchloroacetyl‐6‐aminohexanoic acid (LAHK) was found to be effective in the preparation of a new poly(ester amide) based on lactic acid units with a high yield and a moderate molecular weight. The reaction started in the solid state and proceeded through the formation of potassium chloride salt as the driving force. The use of a monomer having an amide linkage diminished the secondary reactions previously found in the synthesis of polylactide from 2‐halogenopropionates. The polymerization of potassium salt of N‐chloroacetyl‐6‐aminohexanoic acid (GAHK) took place in a similar temperature range as that of the 2‐chloropropionyl derivative; in this way, it was possible to conduct the copolymerization processes. The polymerization kinetics of LAHK and its mixture with GAHK was studied by Fourier transform infrared spectroscopy. The bulk polycondensation reaction was faster for GAHK than for LAHK, but the kinetic differences were not significant enough to prevent copolymerization at a temperature close to 160°C. Therefore, new degradable materials with tuned properties according to the glycolic acid/lactic acid content were obtained. ¹H‐NMR spectroscopy was useful for following the time evolution of the copolymerization process and for determining the final composition. Calorimetric data showed that all of the samples were thermally stable and that decreases in the melting temperature and enthalpy were observed at intermediate compositions. The existence of an eutectic point became proof that effective copolymerization was achieved in the thermal polycondensation process. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43197.