The EuQoS system: a solution for QoS routing in heterogeneous networks [Quality of Service based Routing Algorithms for Heterogeneous Networks]

EuQoS is the acronym for "end-to-end quality of service support over heterogeneous networks", which is a European research project aimed at building an entire QoS framework, addressing all the relevant network layers, protocols, and technologies. This framework, which includes the most common access networks (xDSL, UMTS, WiFi, and LAN) is being prototyped and tested in a multidomain scenario throughout Europe, composing what we call the EuQoS system. In this article we present the novel QoS routing mechanisms that are being developed and evaluated in the framework of this project. The preliminary performance results validate the design choices of the EuQoS system, and confirm the potential impact this project is likely to have in the near future     

Synthesis and characterisation of chromium lutetium gallium garnet solid solution

The chromium lutetium gallium garnet system has been studied. Samples with 2xCaOxCr₂O₃(3 − 2x)Lu₂O₃5Ga₂O₃ (x = 0.025, 0.05, 0.075, 0.1, 0.2 and 0.3,) and xCr₂O₃(3 − x)Lu₂O₃5Ga₂O₃ (x = 0, 0.05, 0.075 and 0.3) compositions have been prepared in Ca,Cr:LGG and Cr:LGG systems, respectively. Samples were prepared by ceramic method, fired at 1250 °C/6 h and characterised by XRD, lattice parameters, UV-vis-NIR spectroscopy, CIE L^*a^*b^* measurements and SEM/EDX. Results indicate that Ca,Cr:LGG and Cr:LGG solid solutions are obtained. In Cr:LGG system only Cr(III) is stabilised in octahedral positions substituting for Lu(III) and Ga(III). Both Cr(III) and Cr(IV) are present in Ca,Cr:LGG. The calcium is a charge compensator to stabilise Cr(IV) and this is the predominant oxidation state up to x = 0.075 composition. From this composition, Cr(III) becomes more stabilised in garnet lattice. Cr(IV) occupies generally tetrahedral and dodecahedral sites substituting for Ga(III) and Lu(III), while Cr(III) is in octahedral site substituting for Ga(III).     

Improvements of fill factor in solar cells based on blends of polyfluorene copolymers as electron donors

The photovoltaic characteristics of solar cells based on alternating polyfluorene copolymers, poly(2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)) (APFO-3), and poly(2,7-(9,9-didodecyl-fluorene)-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)) (APFO-4), blended with an electron acceptor fullerene molecule [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM), have been investigated and compared. The two copolymers have the same aromatic backbone structure but differ by the length of their alkyl side chain. The overall photovoltaic performance of the solar cells is comparable irrespective of the copolymer used in the active layer. However, the fill factor (FF) values of the devices are strongly affected by the copolymer type. Higher FF values were realized in solar cells with APFO-4 (with longer alkyl side chain)/PCBM bulk heterojunction active layer. On the other hand, devices with blends of APFO-3/APFO-4/PCBM were found to render fill factor values that are intermediate between the values obtained in solar cells with APFO-3/PCBM and APFO-4/PCBM active film. Upon using APFO-3/APFO-4 blends as electron donors, the cell efficiency can be enhanced by about 16% as compared to cells with either APFO-3 or APFO-4. The transport of holes in each polymer obeys the model of hopping transport in disordered media. However, the degree of energetic barrier against hopping was found to be larger in APFO-3. The tuning of the photovoltaic parameters will be discussed based on studies of hole transport in the pure polymer films, and morphology of blend layers. The effect of bipolar transport in PCBM will also be discussed.     

A New Donor–Acceptor–Donor Polyfluorene Copolymer with Balanced Electron and Hole Mobility

A new alternating polyfluorene copolymer poly[2,7‐(9,9‐dioctylfluoren)‐alt‐5,5‐(5′,8′‐di‐2‐thienyl‐(2′,3′‐bis‐(3′′‐octyloxyphenyl)‐quinoxaline))] (APFO‐15), which has electron donor–acceptor–donor units in between the fluorene units, is synthesized and characterized. This polymer has a strong absorption and emission in the visible range of the solar spectrum. Its electroluminescence and photoluminescence emissions extend from about 560 to 900 nm. Moreover, solar cells with efficiencies in excess of 3.5 % have been realized from blends of APFO‐15 and an electron acceptor molecule, a methanofullerene [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM). It has also been observed that electron and hole transport is balanced both in the pure polymer phase and in polymer/PCBM bulk heterojunction films, which makes this material quite attractive for applications in opto‐electronic devices.     

Robot vision with cellular neural networks: a practical implementation of new algorithms

Cellular neural networks (CNNs) are well suited for image processing due to the possibility of a parallel computation. In this paper, we present two algorithms for tracking and obstacle avoidance using CNNs. Furthermore, we show the implementation of an autonomous robot guided using only real‐time visual feedback; the image processing is performed entirely by a CNN system embedded in a digital signal processor (DSP). We successfully tested the two algorithms on this robot. Copyright © 2006 John Wiley & Sons, Ltd.     

Parameter identification and computational simulation of polyurethane foaming process by finite pointset method

Numerical simulation of the polyurethane foaming process is a valuable method to analyze the molding process at an early stage of product development to shorten time-to-market cycles and cut costs by using fewer prototypes. However, this process involves highly coupled thermo-chemo-rheological modeling and needs adequate model parameters’ identification. A theoretical model including chemical reactions and thermo-rheological coupling of conservation equations was developed. Based on the theoretical model, three-dimensional numerical simulation for mold filling of the polyurethane foam was carried out by using Finite Pointset Method (FPM) to predict flow field, flow front advancement, temperature and density distributions during mold filling. A FOAMAT system was used to monitor foam height rise and reaction temperature on a cylindrical test tube and foam viscosity was measured by using a dynamic rotational rheometer with parallel-plate system. The parameters of the model were identified by an inverse analysis method which consists in determining the parameters by comparing the computed quantities to those measured experimentally. The overall modeling was validated by using short shot foams obtained with a panel mold cavity. Mold filling of an automotive underlay carpet cavity was investigated numerically. Flow front results were successfully compared to short shot foams obtained with the industrial mold cavity.     

The role of communication practices in the strengthening of counter networks: Case experiences from the health care sector of Mozambique

In this article we provide a theoretically informed empirical analysis of the introduction and use of information and communication technology (ICT) within the primary health care (PHC) sector of Mozambique. The theoretical lens for this analysis is developed from Manuel Castells' (1996, 1997, 2001) ideas on the network society and counter domination. These ideas help us to conceptualize the communicative action required to strengthen the PHC sector as a “counter network,” which has the normative aim to strengthen the health information system (HIS) as a key strategy to improve health care delivery. Taking an informational perspective, the role of communication is highlighted as playing an important constitutive basis in the strengthening of this network. These conceptual ideas are applied to the empirical analysis of an ongoing project (the Health Information Systems Programme or HISP), and to analyze some key constraints and strategies for strengthening these networks. This study makes key contributions to both the theoretical and practical domains of HIS in developing countries. © 2005 Wiley Periodicals, Inc.     

An evolutionary approach to complex schema matching

The schema matching problem can be defined as the task of finding semantic relationships between schema elements existing in different data repositories. Despite the existence of elaborated graphic tools for helping to find such matches, this task is usually manually done. In this paper, we propose a novel evolutionary approach to addressing the problem of automatically finding complex matches between schemas of semantically related data repositories. To the best of our knowledge, this is the first approach that is capable of discovering complex schema matches using only the data instances. Since we only exploit the data stored in the repositories for this task, we rely on matching strategies that are based on record deduplication (aka, entity-oriented strategy) and information retrieval (aka, value-oriented strategy) techniques to find complex schema matches during the evolutionary process. To demonstrate the effectiveness of our approach, we conducted an experimental evaluation using real-world and synthetic datasets. The results show that our approach is able to find complex matches with high accuracy, similar to that obtained by more elaborated (hybrid) approaches, despite using only evidence based on the data instances.     

Knowledge base specification to automate the fluid critical point of fluids

In this paper an analytical procedure implemented to structure the knowledge required by an expert system applied for controlling a chemical process is described. The analytical approach is based on L ifecycle of Systems and on Task Model approaches. It was validated with an experimental procedure related to the determination of the critical point of pure fluids (CO₂, N₂O, SF₆) and mixtures of low concentration (CO₂-limonene). For the implementation of the control system an expert system shell (CHRONOS?) was used.