Stationarity of electricity series in MENA countries

This paper investigates the stationary properties of electric power consumption in 18 countries in the Middle East and North Africa (MENA) by using yearly data over the period 1971–2013. After having controlled for the presence of cross-section dependence, the ‘second generation’ panel unit root tests reveal mixed results. In fact, the conclusions depend on the choice of the deterministic component (constant vs. constant and trend).     

Effect op the preparation conditions on the reducibility of Cu-Co based oxides

The nature of the active sites of Cu-Co-Al Catalysts used to convert synthesis gas to methanol and higher alcohols is still a matter of debate. The main difficulty to discern the nature of the synergism responsible for alcohol formation is related to the Co reducibility under reaction conditions. In this paper we studied the influence of the preparation conditions on the reducibility of Co. Binary Cu-Co, Cu-Al and Co-Al, and ternary Cu-Co-Al samples were prepared by coprecipitation and characterized by temperature-programmed reduction. X-ray powder diffraction and diffuse reflectance spectroscopy techniques. Depending on the Co/Al ratio and calcination atmosphere, the Co ions were present in three different phases before H₂ activation: CuCoO₂, GO₃O₄ and partly inverse CoAl₂O₄ spinel. The Co reducibility was in the order CuCoO₂ > Co₃O₄ > Co_oh ions in CoAl₂O₄ > Co_td ions in CoAl₂O₄. In all the cases, the presence of Cu activated the reduction of Co²⁺ and Co³⁺ ions. The mixed oxides obtained in nitrogen did not contain CO₃O₄ and the CuCoO₂ phase was formed only when the Co/Al atomic ratio was greater than 0.5. The samples calcined in air contained CO₃O₄ but not CuCoO₂. All the samples contained CoAl₂O₄, spinel phase with finely dispersed CuO. It was found that the preparative procedures and the chemical composition of the samples greatly Influence the reducibility of Co ions, thereby determining the kind of Cu-Co interaction.     

A nonsmooth frictional contact formulation for multibody system dynamics

We present a new node-to-face frictional contact element for the simulation of the nonsmooth dynamics of systems composed of rigid and flexible bodies connected by kinematic joints. The equations of motion are integrated using a nonsmooth generalized-α time integration scheme and the frictional contact problem is formulated using a mixed approach, based on an augmented Lagrangian technique and a Coulomb friction law. The numerical results are independent of any user-defined penalty parameter for the normal or tangential component of the forces and, the bilateral and the unilateral constraints are exactly fulfilled both at position and velocity levels. Finally, the robustness and the performance of the proposed algorithm are demonstrated by solving several numerical examples of nonsmooth mechanical systems involving frictional contact.     

Adjoint time domain method for fluorescent imaging in turbid media

Application of adjoint time domain methods to the inverse problem in 3D fluorescence imaging is a novel approach. We demonstrate the feasibility of this approach experimentally on the basis of a time gating technique completely in the time domain by using a small number of time windows. The evolution of the fluorescence energy density function inside a highly scattering cylinder was reconstructed together with optical parameters. Reconstructed energy density was used in localizing two fluorescent tubes. Relatively accurate reconstruction demonstrates the effectiveness and the potential of the proposed technique.     

Dynamic time-resolved diffuse spectroscopy based on supercontinuum light pulses

We present a detailed characterization of a system for fast time-resolved spectroscopy of turbid media based on supercontinuum generation in a photonic crystal fiber. The light source provides subpicosecond pulses in the 550-1000-nm spectral range, at 85 MHz, at an average power of up to 50 mW. Wavelength-resolved detection is accomplished by means of a spectrometer coupled to a 16-channel, multianode photomultiplier tube, giving a resolution of 4.5-35 nm/channel, depending on the grating. Time-dispersion curves are acquired with time-correlated single-photon counting, and absorption and reduced scattering coefficients are determined by fitting the data to the diffusion equation. We characterized the system by measuring the time-resolved diffuse reflectance of epoxy phantoms and by assessing the performance in terms of accuracy, linearity, noise sensitivity, stability, and reproducibility. The results were similar to those from previous systems, whereas the full-spectrum (610-810 nm) acquisition time was as short as 1 s owing to the parallel acquisition. We also present the first in vivo real-time dynamic spectral measurements showing tissue oxygenation changes in the arm of a human subject.     

Robust Estimation of Object Dimensions and External Defect Detection with a Low-Cost Sensor

The measurement of object dimensions as well as the detection and localization of external defects are of large importance for many sectors in industry including agriculture, transportation and production. In this paper we investigate the feasibility of using commercial depth-sensing devices, based on a time-of-flight technology, such as the Kinect v2 camera, for the measurement and inspection of cuboidal objects (boxes). This paper presents a simplified system using only one Kinect sensor. At the beginning, object dimensions are roughly estimated by discovering the best-fit planes for a cloud of point based on a modified version of RANSAC (RANdom Sample Consensus). The precise geometry and morphology of the objects are then achieved by a transformation from depth to RGB representation of the points estimated as belonging to the object. RGB representation is finally processed (using scanlines on the RGB plane perpendicular to the initial edge estimate) to approximate at best the contour of the bounding box. In addition to the above, the paper proposes a method to automatically highlight defects on the objects’ surfaces: this inspection task is performed through the analysis of both the 2D object contours and the histogram of the normalized depth values. The proposed methodology takes a few seconds to deliver the results for the monitored object and, it experienced encouraging results in terms of accuracy. Indeed, the system measured the dimensions of a set of cuboidal objects with an average error of 5 mm and it was able to identify and locate defects and holes on lateral and topmost surfaces. The experimental outcomes pointed out that the system could be effectively exploited within industrial inspection applications, even more so if the low cost of the system is taken under consideration.     

Achieving self-healing in service delivery software systems by means of case-based reasoning

Self-healing, i.e. the capability of a system to autonomously detect failures and recover from them, is a very attractive property that may enable large-scale software systems, aimed at delivering services on a 24/7 fashion, to meet their goals with little or no human intervention. Achieving self-healing requires the elicitation and maintenance of domain knowledge in the form of 〈service failure diagnosis, repair plan〉 patterns, a task which can be overwhelming. Case-Based Reasoning (CBR) is a lazy learning paradigm that largely reduces this kind of knowledge acquisition bottleneck. Moreover, the application of CBR for failure diagnosis and remediation in software systems appears to be very suitable, as in this domain most errors are re-occurrences of known problems. In this paper, we describe a CBR approach for providing large-scale, distributed software systems with self-healing capabilities, and demonstrate the practical applicability of our methodology by means of some experimental results on a real world application.     

Advances in Clustering Collaborative Filtering by means of Fuzzy C-means and trust

Several approaches for recommending products to the users are proposed in literature, and collaborative filtering has been proved to be one of the most successful techniques. Some issues related to the quality of recommendation and to computational aspects still arise (e.g., cold-start recommendations). In this paper, we investigate the application of model-based Collaborative Filtering (CF) techniques and in particular propose a clustering CF framework and two clustering CF algorithms: Item-based Fuzzy Clustering Collaborative Filtering (IFCCF) and Trust-aware Clustering Collaborative Filtering (TRACCF). We compare several approaches by means of Epinions, MovieLens, Jester, and Poste Italiane datasets (with real customers). Experimental results show an increased value of coverage of the recommendations provided by TRACCF without affecting recommendation quality. Moreover, trust information guarantees high level recommendation for different users.     

A New Class of 1‐Aryl‐5,6‐dihydropyrrolo[2,1‐a]isoquinoline Derivatives as Reversers of P‐Glycoprotein‐Mediated Multidrug Resistance in Tumor Cells

A number of aza‐heterocyclic compounds, which share the 5,6‐dihydropyrrolo[2,1‐a]isoquinoline (DHPIQ) scaffold with members of the lamellarin alkaloid family, were synthesized and evaluated for their ability to reverse in vitro multidrug resistance in cancer cells through inhibition of P‐glycoprotein (P‐gp) and/or multidrug‐resistance‐associated protein 1. Most of the investigated DHPIQ compounds proved to be selective P‐gp modulators, and the most potent modulator, 8,9‐diethoxy‐1‐(3,4‐diethoxyphenyl)‐3‐(furan‐2‐yl)‐5,6‐dihydropyrrolo[2,1‐a]isoquinoline‐2‐carbaldehyde, attained sub‐micromolar inhibitory potency (IC₅₀: 0.19 μm ). Schiff bases prepared by the condensation of some 1‐aryl‐DHPIQ aldehydes with p‐aminophenol also proved to be of some interest, and one of them, 4‐((1‐(4‐fluorophenyl)‐5,6‐dihydro‐8,9‐dimethoxypyrrolo[2,1‐a]isoquinolin‐2‐yl)methyleneamino)phenol, had an IC₅₀ value of 1.01 μm . In drug combination assays in multidrug‐resistant cells, some DHPIQ compounds, at nontoxic concentrations, significantly increased the cytotoxicity of doxorubicin in a concentration‐dependent manner. Studies of structure–activity relationships and investigation of the chemical stability of Schiff bases provided physicochemical information useful for molecular optimization of lamellarin‐like cytotoxic drugs active toward chemoresistant tumors as well as nontoxic reversers of P‐gp‐mediated multidrug resistance in tumor cells.     

Comparison of the effect of epoxy microspheres on the thermomechanical and rheological properties of an epoxy resin system

The rheological and thermomechanical behaviors of toughened epoxy resins filled with thermosetting microsized spherical particles were investigated. Two epoxy systems were used to prepare microspheres: a Bisphenol A‐type resin (EPON825) cured with 2,4‐diaminotoluene and a Bisphenol F‐based epoxy resin (PY306) crosslinked with diethyltoluenediamine. Both systems of microspheres were synthesized through dispersion polymerization and differed to each other in size, as evidenced by morphological analysis. These microparticles were blended, in different weight percents (10 and 20 wt%), with a matrix consisting of diglycidyl ether of Bisphenol A (EPON828) and 3,3′‐diaminodiphenylsulphone (3,3′DDS). Rheological behavior of the prepared blends was preliminarily studied. After cure, the dynamic‐mechanical properties of the composites were also investigated. Results indicated that the reactivity of the uncured blends, as well as the viscoelastic properties of crosslinked systems, are influenced not only by the nature and the amount of the microparticles introduced, but also, in a significant way, by their size. POLYM. ENG. SCI. 46:1739–1747, 2006. © 2006 Society of Plastics Engineers.