Game theoretic bandwidth procurement mechanisms in live P2P streaming systems

With the dramatic growth of Internet video streaming applications, resource provisioning for video streaming systems to satisfy their upload bandwidth deficit is a challenging task. The design of incentive mechanisms for taking advantage of unused upload capability of helper peers is proven to be a viable, cost-effective solution for this problem. The existing incentive mechanisms for video streaming systems do not consider the hierarchical nature of helper-server interactions, the limited budget of server to procure the needed bandwidth, and limited information of helpers about the other parties in the system. To address these issues, we designed cooperation mechanisms for two different cases: in the full-information case where the server has the full control over the amount of payments to each helper, a Stackelberg helping game is formulated in which the server as leader determines the amount of payment for each helper and then, helpers as followers decide on their amount of contributed bandwidth accordingly. We characterize the Stackelberg Equilibrium (SE) point of game in which the server shares the benefits of bandwidth sharing with the helpers through a market mechanism. In the partial information case where the helpers’ cost and utility functions are private and unknown to the server, we propose a budget-limited reverse auction in which the helpers, in contrast to the former case, announce the lowest price at which they are willing to sell their upload bandwidth first and the server then selects a subset of the helpers and pays them proportional to their contributions. The results of extensive simulations reveal that the mechanisms are truthful and result in lower server workload and higher peers’ streaming rate and delivery ratio.     

An efficient and controllable ultrasonic-assisted microwave route for flower-like Ta(V)–MOF nanostructures: preparation,fractional factorial design,DFT calculations,and high-performance N<Subscript>2</Subscript> adsorption

With respect to different applications of metal–organic framework (MOF) in the medical, industrial and environmental fields, it is very important to choose a new structure that can be synthesized by fast, eco-friendly and affordable methods with distinctive properties so that the properties could be systematically controlled. In this study, new Ta–MOF nanostructures are synthesized by novel methods of microwave (Mw) and ultrasonic assisted microwave (UAMw) in environmental conditions. The final products are characterized by relevant techniques. Although in the both methods, the synthesized products have favourable properties; the use of the UAMw method would produce samples with distinct features such as high thermal stability of 240 °C, average particle size distribution (PSD) of 23 nm and significant specific surface area (SSA) of 2012 m²/g. For a better comprehension of the Ta–MOF formation, computational studies are performed using DFT calculations. In order to investigate the effect of the synthesis parameters on different features of the products, the fractional factorial design is used. The results of analysis of variance confirm that the parameters such as Mw power, Mw duration, ultrasonic temperature, ultrasonic power and ultrasonic duration have a significant effect on PSD and SSA of Ta–MOF samples. Due to the fractional factorial design of the experiments, response surface methodology would optimize the probability of producing samples with the small PSD of 15 nm and high SSA of 2588 m²/g; this desirable amount would provide situations to use these compounds in diverse fields.     

Detection of river/sea ice deformation using satellite interferometry: limits and potential

In this paper, we present a study consisting of the application of radar interferometry for river/sea ice monitoring in inhabited regions and on commercial waterways. The sites studied are located in Canadian regions where ice jams constitute a common winter hazard that can cause extensive socio-economic damage and impose severe restrictions on ship traffic. ERS and Radarsat images were jointly used with traditional in situ observations to detect ice break-up in order to prevent ice jams and related problems. A coherence study served to define the synthetic aperture radar interferometry (InSAR) limits for river/sea ice dynamics monitoring. Other factors that also help to define the limits of InSAR technology for this application include the frequency of image acquisition, the minimum dimension of detected ice floes and the determination of appropriate ice types. Significant phase shifts were found for small ice floes of several hundred metres with ERS-tandem images. The analysis of the interferograms showed that it is possible to detect deformations in the ice shelf and to discriminate quantitatively the horizontal and vertical components of ice movement when the interferograms are combined with traditional observations such as meteorological data, water level, water flow and ice charts. The deformation estimated on a piece of fast river ice can be interpreted as the first sign of the ice break-up. On an estuary river that is a busy seaway, a qualitative interpretation of the interferograms served to highlight the interaction of river and tidal flows affecting the ice cover. We showed, in particular, the potential of radar interferometry and its integration with other techniques to help the authorities to prevent problems related to ice jams.     

Polynomial characterization of inhomogeneous media and theirreconstruction using an open-ended waveguide

B. Sanadiki and M. Moustafavi (1991) described how an inhomogeneous continuously varying dielectric profile can be inverted using a stepwise successive refinement procedure when an open-ended waveguide is used as the source. Here, an alternative approach based on polynomial characterization of the dielectric medium is discussed. It is shown that this method is more efficient and avoids the convergence difficulties of the previous method for most cases except for discontinuous or stratified profiles     

Medial canthoplasty for optimum support of the lower eyelid in 14 patients

BACKGROUND AND OBJECTIVES: Medial canthoplasty surgically fuses the upper and lower lids medial to the puncta. The authors modified the procedure by inserting a temporary lacrimal stent in order to avoid kinking and scar contracture of the canaliculi. PATIENTS AND METHODS: A medial canthoplasty successfully corrected lower eyelid laxity in 14 patients with the following conditions: (1) exposure and/or neurotrophic keratitis with medial ectropion and/or retraction of the lower eyelid (11 patients), and (2) inability to retain a prosthesis because of lower eyelid ectropion and contracture of the inferior conjunctival fornix (3 anophthalmic patients). RESULTS: All patients had a satisfactory cosmetic result despite minimal vertical and horizontal narrowing of the palpebral fissure. Complications included partial wound dehiscence and pyogenic granuloma. CONCLUSION: The modified medial canthoplasty described in this article corrects medial ectropion with minimal cosmetic deformity.     

H2 production by γ and He ions water radiolysis, effect of presence TiO2 nanoparticles

The effect of TiO₂ particles on the yield of H₂ formation under water radiolysis is measured. Irradiations were performed using a ⁶⁰Co γ−ray source as well as with He ions particles (4He2⁺) generated by a cyclotron with an external beam energy of 6 MeV. The resulting hydrogen as a stable product of radiolysis was measured by mass spectrometry. G(H₂) obtained for water radiolysis by He ions−irradiation in aerated and argon water are found to be 1.91 × 10⁻⁷ and 1.35 × 10⁻⁷ mol J⁻¹, respectively. In the presence of titanium oxide anatase−type dispersed in water, under He ions−irradiation, G(H₂) is found to increase slightly from 1.04 × 10⁻⁷ to 1.35 × 10⁻⁷ mol J⁻¹ by increasing the specific surface from 8 to 253 m²/g, respectively. Under γ-irradiation, G(H₂) is found to be 0.41 × 10⁻⁷ mol J⁻¹ close to primary yield of hydrogen in presence of OH. Radical scavenger. In addition, radiolysis of water adsorbed in the titanium oxide with low water content, which corresponds to a few layers of water sorbed onto the solid surface gives a huge values of the G(H₂). For the same amount of water, with using the dose absorbed by TiO₂ particles, for He ions-irradiation, G(H₂) increases from 14.5 × 10⁻⁷ to 35 × 10⁻⁷ mol J^-1 by increasing the surface area of TiO₂ nanoparticles from 4 to 52 m²/g, respectively. For γ−irradiation G(H₂) is found to be 5.25 × 10⁻⁷ mol J^-1 for the sample with 8 m²/g specific surface area.     

Partnership ability and co-authorship network of information literacy field

Scientometrics - Scientific collaboration or co-authorship has different forms and can be a factor in creating knowledge and even increasing the quality of scientific works. Beyond the quantity,...     

Effect of Particle Shape on Inline Particle Size Measurement Techniques

The influence of the particle shape on the results of different measuring techniques was investigated. Considered were single‐frequency ultrasound technique, 3D optical reflectance measurement (advanced particle analyzing system with multi capture signal technology), and focused‐beam reflectance measurement probes as techniques which are usable inline and in suspension density ranges usually present in industrial crystallization processes. Advantages and shortcomings of these techniques are compared and discussed.     

A Stochastic Approximation Approach for Foresighted Task Scheduling in Cloud Computing

Wireless Personal Communications - With the increasing and elastic demand for cloud resources, finding an optimal task scheduling mechanism become a challenge for cloud service providers. Due to...