497 research outputs found

    Network traffic flow optimization under performance constraints

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    In this paper, a model-based perimeter control policy for large-scale urban vehicular networks is proposed. Assuming a homogeneously loaded vehicle network and the existence of a well-posed Network Fundamental Diagram (NFD), we describe a protected network throughout its aggregated dynamics including nonlinear exit flow characteristics. Within this framework of constrained optimal boundary flow gating, two main performance metrics are considered: (a) first, connected to the NFD, the concept of average network travel time and delay as a performance metric is defined; (b) second, at boundaries, we take into account additional external network queue dynamics governed by uncontrolled inflow demands. External queue capacities in terms of finite-link lengths are used as the second performance metric. Hence, the corresponding performance requirement is an upper bound of external queues. While external queues represent vehicles waiting to enter the protected network, internal queue describes the protected network’s aggregated behavior. By controlling the number of vehicles joining the internal queue from the external ones, herewith a network traffic flow maximization solution subject to the internal and external dynamics and their performance constraints is developed. The originally non-convex optimization problem is transformed to a numerically efficiently convex one by relaxing the performance constraints into time-dependent state boundaries. The control solution can be interpreted as a mechanism which transforms the unknown arrival process governing the number of vehicles entering the network to a regulated process, such that prescribed performance requirements on travel time in the network and upper bound on the external queue are satisfied. Comparative numerical simulation studies on a microscopic traffic simulator are carried out to show the benefits of the proposed method

    Effizienter Erwerb chirurgischer Basistechniken durch "blended learning"

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    Zusammenfasssung: Hintergrund: Große Studierendenzahlen und heterogene Dozierende erschweren einheitliche Kursgestaltungen und die objektive Standardisierung von Prüfungen im chirurgischen Fertigkeitstraining. Diese Arbeit zeigt die Vorteile des Einsatzes neuer Medien im "Blended-learning-Konzept" für das Fertigkeitstraining im Studiengang Humanmedizin der Universität Basel. Material und Methoden: Der studentische chirurgische "Nahtkurs" wurde nach einem Blended-learning-Konzept mit multimedialer CD, Präsenzveranstaltung und SkillsLab restrukturiert. Die Lernziele des Kurses wurden am Ende der Studienjahre anhand von Posten mit Checklisten im OSCE ("objective structured clinical examination") überprüft. Die studentische Kursbeurteilung sowie die Prüfungsergebnisse vor und nach Einführung des "blended learning" wurden miteinander verglichen. Ergebnisse: Sowohl die Beurteilungen der eingesetzten Lehrmittel, des subjektiven Übungserfolges und des prospektiven Nutzens für das Wahlstudienjahr (Praktisches Jahr) als auch die Gesamtkursbeurteilung waren nach Einführung des Blended-learning-Konzeptes signifikant höher als im alten Kursformat. Auch der Anteil an bestandenen Prüfungen war mit einem Zuwachs von 10% signifikant im Vergleich zum alten Kurs erhöht. Schlussfolgerung: "Blended learning” kann sowohl Wahrnehmung und Leistung als auch die Effizienz des Fertigkeitstrainings und der Betreuungszeit verbessern. Dadurch werden indirekt Ressourcen gespart. Chirurgische Verfahren können klar und übersichtlich vermittelt werde

    Compare and Reweight: Distinctive Image Captioning Using Similar Images Sets

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    A wide range of image captioning models has been developed, achieving significant improvement based on popular metrics, such as BLEU, CIDEr, and SPICE. However, although the generated captions can accurately describe the image, they are generic for similar images and lack distinctiveness, i.e., cannot properly describe the uniqueness of each image. In this paper, we aim to improve the distinctiveness of image captions through training with sets of similar images. First, we propose a distinctiveness metric -- between-set CIDEr (CIDErBtw) to evaluate the distinctiveness of a caption with respect to those of similar images. Our metric shows that the human annotations of each image are not equivalent based on distinctiveness. Thus we propose several new training strategies to encourage the distinctiveness of the generated caption for each image, which are based on using CIDErBtw in a weighted loss function or as a reinforcement learning reward. Finally, extensive experiments are conducted, showing that our proposed approach significantly improves both distinctiveness (as measured by CIDErBtw and retrieval metrics) and accuracy (e.g., as measured by CIDEr) for a wide variety of image captioning baselines. These results are further confirmed through a user study

    Optimization and characterization of zeolite-titanate for ibuprofen elimination by sonication/hydrogen peroxide/ultraviolet activity

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    In this study, a photo-catalyst of titanium oxide was coated on zeolite by the sol–gel method. The generation of the zeolite-titanate photo-catalyst was optimized at conditions of calcination temperature (300, 350, 400 and 500 °C), calcination time (1, 2, 3, and 4 h), and titanate content (0, 2, 4, 6, and 8 mL). The catalyst was used for ‘Sonication/UV/H2O2″ activity and finally, eliminating ibuprofen. Physicochemical properties of the as-built photo-catalysts for all optimized conditions were determined using FESEM-EDX-mapping, BET, FTIR, and XRD. The highest percentage of ibuprofen removal (98.9%) was obtained at conditions of zeolite to titanium ratio of 1 g: 2 mL, time in the furnace of 1 h, and temperature of the furnace of 350 °C. The optimum photo-catalytic (namely, Cat-350-1-2) had a surface area value of 39 m2/g and a crystalline size of 4.9 nm. The surface area for all photo-catalysts increased after being used for ibuprofen removal, possibly due to ultrasonic waves. The presence of Ti-O, benzene ring, O-Al-O, O-Si-O, C–H, and O–H in the photo-catalysts structure were confirmed. Growing the calcination time resulted in an increase in the crystallinity of titanium dioxide in the photo-catalysts and, ultimately a reduction in the ibuprofen removal. The consumed energy by the developed system was calculated for the presence (0.094 kJ/g) and absence (17.5 kJ/g) of the ultrasonic wave. The degradation pathway and reaction kinetic are also explored and proposed. The results showed that the ultrasonic-UV-activated H2O2-based technique can be applied as an alternative method for ibuprofen removal from aqueous medi

    MIL-101(Cr)-cobalt ferrite magnetic nanocomposite: synthesis, characterization and applications for the sonocatalytic degradation of organic dye pollutants

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    In this study, for the first time, a novel magnetically recyclable MIL-101(Cr)/CoFe2O4nanocomposite was preparedviaa facile solvothermal method. The morphology, structural, magnetic and optical properties of the nanocomposite were characterizedviafield emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), UV-visible spectroscopy (UV-visible) and BET surface area analysis. Furthermore, the sonocatalytic activity of the MIL-101(Cr)-based magnetic nanocomposite was explored for the degradation of organic dye pollutants such as Rhodamine B (RhB) and methyl orange (MO) under ultrasound irradiation in the presence of H2O2. Under optimized conditions, the degradation efficiency reached 96% for RhB and 88% for MO. The sonocatalytic activity of MIL-101(Cr)/CoFe2O4was almost 12 and 4 times higher than that of the raw MIL-101(Cr) and pure CoFe2O4, respectively. The improved sonocatalytic performance of the as-prepared binary nanocomposite can be attributed to the relatively high specific surface area of MIL-101(Cr) and magnetic property of CoFe2O4, as well as the fast generation and separation of charge carriers (electrons and holes) in MIL-101(Cr) and CoFe2O4. In addition, the trapping tests demonstrated that ·OH radicals are the main active species in the dye degradation process. Moreover, the most influencing factors on the sonocatalytic activity such as the H2O2amount, initial dye concentration and catalyst dosage were investigated. Finally, the nanocomposite was magnetically separated and reused without any observable change in its structure and performance even after four consecutive runs

    Achieving Steady and Stable Energy from AlGaAsGaAs Solar Cells

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    The hetero junction operating as a solar cell is based on n GaAs p GaAs p Al0.75Ga0.25As. This paper investigates the influence of radiation electron ray on layers of hetero-junction AlGaAsGaAs. Long term operation in the radiation zone degrades solar cell power operating parameters and reduces overall cell’s life. The impact of radiation electron ray has been analyzed with various doses on layers of the AlGaAsGaAs hetero junction. V-A characteristics and parameters such as the photocurrent density (Jsc), voltage at open circuit (Voc) and energy conversion efficiency ( (η), are evaluated for different doses of electron radiations. It is shown that current and voltage decrease when irradiation doses increase. Further, Jsc and η parameters decrease proportionally to the increase of the electron radiation doses whereas Voc is only slightly decreased

    Acoustic Analysis of Crying Signal in Infants with Disabling Hearing Impairment

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    Objective: Crying is a multimodal, dynamic behavior and the first way to communicate. Early identification of hearing impairment is critical for prevention of speech and language disorders. The present study aimed to assess the acoustic features of infant's cry signals to find possible differences between two groups including hearing-impaired (HI) infants and normal hearing (NH) control. Methods: The data were collected from 34 (17 HI, 17 NH) infants under 2 months of age. Recording of the infant cry signals was collected during the examination of the Babinski reflex and was subsequently submitted for acoustic analysis. The total duration of the recording for each infant was approximately 30 seconds. The acoustical features included fundamental frequency (F0), formants (F1, F2, and F3), intensity, jitter, shimmer, ratios of F2/F1 and F3/F1, ratio of harmonic to noise, and voice break. The recording device was an Olympus ws-321M voice recorder with 44,100 Hz sampling frequency in the stereo form. Praat analysis software (version 27, 3, 5) was used to analyze the crying signals. The data were then statistically analyzed using SPSS version 21. Results: Acoustic analysis of the crying signals showed that HI infants have lower intensity and higher F0 and voice break than NH infants. However, the other differences were not statistically significant. Conclusion: The results of the present study demonstrated that the acoustic components including F0, intensity, and voice break may be used as indices to discriminate HI infants from NH infants under 2 months of age. These findings can be increased our knowledge concerning the functional mechanisms of the vocal organ in HI and NH infants. © 201

    A Mutation in HOXA2 Is Responsible for Autosomal-Recessive Microtia in an Iranian Family

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    Microtia, a congenital deformity manifesting as an abnormally shaped or absent external ear, occurs in one out of 8,000-10,000 births. We ascertained a consanguineous Iranian family segregating with autosomal-recessive bilateral microtia, mixed symmetrical severe to profound hearing impairment, and partial cleft palate. Genome-wide linkage analysis localized the responsible gene to chromosome 7p14.3-p15.3 with a maximum multi-point LOD score of 4.17. In this region, homeobox genes from the HOXA cluster were the most interesting candidates. Subsequent DNA sequence analysis of the HOXA1 and HOXA2 homeobox genes from the candidate region identified an interesting HOXA2 homeodomain variant: a change in a highly conserved amino acid (p.Q186K). The variant was not found in 231 Iranian and 109 Belgian control samples. The critical contribution of HoxA2 for auditory-system development has already been shown in mouse models. We built a homology model to predict the effect of this mutation on the structure and DNA-binding activity of the homeodomain by using the program Modeler 8v2. In the model of the mutant homeodomain, the position of the mutant lysine side chain is consistently farther away from a nearby phosphate group; this altered position results in the loss of a hydrogen bond and affects the DNA-binding activity. © 2008 The American Society of Human Genetics
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