Use of Neural Network Based Prediction Algorithms for Powering Up Smart Portable Accessories

Neural Processing Letters - Emerging Trends in the use of smart portable accessories, particularly within the context of the Internet of Things (IoT), where smart sensor devices are employed for...     

Adaptive course generation through learning styles representation

This paper presents an approach to automatic course generation and student modeling. The method has been developed during the European funded projects Diogene and Intraserv, focused on the construction of an adaptive e-learning platform. The aim of the platform is the automatic generation and personalization of courses, taking into account pedagogical knowledge on the didactic domain as well as statistic information on both the student’s knowledge degree and learning preferences. Pedagogical information is described by means of an innovative methodology suitable for effective and efficient course generation and personalization. Moreover, statistic information can be collected and exploited by the system in order to better describe the student’s preferences and learning performances. Learning material is chosen by the system matching the student’s learning preferences with the learning material type, following a pedagogical approach suggested by Felder and Silverman. The paper discusses how automatic learning material personalization makes it possible to facilitate distance learning access to both able-bodied and disabled people. Results from the Diogene and Intraserv evaluation are reported and discussed.     

Excitation energy-dependent nature of Raman scattering spectrum in GaInNAs/GaAs quantum well structures

The excitation energy-dependent nature of Raman scattering spectrum, vibration, electronic or both, has been studied using different excitation sources on as-grown and annealed n- and p-type modulation-doped Ga_1 − xIn_xN_yAs_1 − y/GaAs quantum well structures. The samples were grown by molecular beam technique with different N concentrations (y = 0%, 0.9%, 1.2%, 1.7%) at the same In concentration of 32%. Micro-Raman measurements have been carried out using 532 and 758 nm lines of diode lasers, and the 1064 nm line of the Nd-YAG laser has been used for Fourier transform-Raman scattering measurements. Raman scattering measurements with different excitation sources have revealed that the excitation energy is the decisive mechanism on the nature of the Raman scattering spectrum. When the excitation energy is close to the electronic band gap energy of any constituent semiconductor materials in the sample, electronic transition dominates the spectrum, leading to a very broad peak. In the condition that the excitation energy is much higher than the band gap energy, only vibrational modes contribute to the Raman scattering spectrum of the samples. Line shapes of the Raman scattering spectrum with the 785 and 1064 nm lines of lasers have been observed to be very broad peaks, whose absolute peak energy values are in good agreement with the ones obtained from photoluminescence measurements. On the other hand, Raman scattering spectrum with the 532 nm line has exhibited only vibrational modes. As a complementary tool of Raman scattering measurements with the excitation source of 532 nm, which shows weak vibrational transitions, attenuated total reflectance infrared spectroscopy has been also carried out. The results exhibited that the nature of the Raman scattering spectrum is strongly excitation energy-dependent, and with suitable excitation energy, electronic and/or vibrational transitions can be investigated.     

Characterization of Heat Treated Titanium-Based Implants by Nondestructive Eddy Current and Ultrasonic Tests

This study presents nondestructive characterization of microstructure and mechanical properties of heat treated Ti, Ti-Cu, and Ti-6Al-4V titanium-based alloys and 17-4 PH stainless steel alloy for biomedical implant applications. Ti, Ti-Cu, and 17-4 PH stainless steel based implants were produced by powder metallurgy. Ti-6Al-4V alloy was investigated as bulk wrought specimens. Effects of sintering temperature, aging, and grain size on mechanical properties were investigated by nondestructive and destructive tests comparatively. Ultrasonic velocity in specimens was measured by using pulse-echo and transmission methods. Electrical conductivity of specimens was determined by eddy current tests. Determination of Young’s modulus and strength is important in biomedical implants. Young’s modulus of specimens was calculated by using ultrasonic velocities. Calculated Young’s modulus values were compared and correlated with experimental values.     

Controlling of electronic parameters of GaAs Schottky diode by poly(3,4-ethylenedioxithiophene)-block-poly(ethylene glycol) organic interlayer

The electronic properties of metal-organic semiconductor-inorganic semiconductor structure between GaAs and poly(3,4-ethylenedioxithiophene)-block-poly(ethylene glycol) organic film have been investigated via current-voltage and capacitance-voltage methods. The Au/PEDOT/n-GaAs contact exhibits a rectification behavior with the barrier height of 0.69 eV and ideality factor value of 3.94. The barrier height of the studied diode (0.67 eV) is lower than that of Ni/n-GaAs/In (0.85 eV) and Au/n-GaAs/In Schottky diodes. The decrease in barrier height of Au/n-GaAs/In Schottky diode is likely to be due to the variation in the space charge region in the GaAs. The obtained results indicate that control of the interfacial potential barrier for metal/n-GaAs diode was achieved using thin interlayer of the poly(3,4-ethylenedioxithiophene)-block-poly(ethylene glycol).     

Comparative study between corpus cavernosum-electromyography findings and electron microscopy of cavernosal muscle biopsies in erectile dysfunction patients

BACKGROUND/AIMS: The colonic response to obstruction is poorly understood. Thickening of the proximal bowel following colonic stricture may be due to increased protein synthesis. We have investigated the colonic morphology and collagen concentration during the development of left-sided colonic obstruction in an animal model. METHODS: Twelve male Wistar rats received either a silk ligature obstruction of the colon 2.5 cm above the peritoneal reflection (n = 6) or manipulation of the left colon (controls, n = 6). Twenty-four hours later, three colonic specimens from the ligature zone and from 1 cm proximal and distal to this site, or from equivalent regions in controls, were assayed for hydroxyproline concentration. RESULTS: In controls there was no difference in hydroxyproline concentration between colonic sites. In obstructed rats, the hydroxyproline concentration was greater both at the ligature and distally, when compared with the proximal region. The hydroxyproline concentration was higher (p < 0.05) than corresponding control values at the ligature site (14.95 +/- 2.76 vs. 10.97 +/- 1.95 microgram/mg of dry tissue mean +/- s.d.) but not on either side. CONCLUSION: The colonic collagen concentration is equivalent or raised near an obstruction, demonstrating that obstructed colon may possess an enhanced capacity to hold sutures.     

Use of DTA with infrared analysis of evolved gas to investigate the effect of flame retardants on gas evolution from pyrolysed cellulose (cotton)

DTA combined with infrared analysis of the evolved gas (EGA) has been used to study the temperature behaviour, both in air and nitrogen, of commercial phosphorus- and nitrogen- and/or bromine-containing flame retardants applied to cotton. By reference to the DTA traces and also the maxima occurring in the CO, CO₂ and H₂O evolution rates, seven significant peak temperatures were assigned. Two new relatively low temperature peaks have been observed: the higher of these is DTA-sensitive and occurs in all unretarded and retarded samples and is ascribed to the formation of an ‘activated cellulose’ state previously proposed by Bradbury, Sakai and Shafizadeh;¹⁷ the lower peak is an exotherm (188-220°C) associated with H₂O and CO₂ evolution from flame-retarded samples only. These observations are interpreted in terms of the mechanism of the cellulose pyrolysis/combustion and the influence of the flame retardants.