Sharif Digital Repository

Due to special constraints in peer-to-peer (P2P) networks (such as bandwidth limitation) and because of their highly dynamic characteristics, a single node cannot provide a reliable multimedia stream to the receivers. Several multi-sender algorithms are proposed to reliably deliver a media stream to the receiver through the intrinsically unreliable P2P networks. Based on upload bandwidths and availability of peers as well as the bandwidths of the links connecting the senders and the receiver, PROMISE selects a set of active senders to maximize the expected bit-rate delivered to the receiver. By careful investigation of PROMISE, in this paper, we present why and how it deviates from finding... 

In this study, a composite patch repair will be designed for an aluminum plate with a central crack placed at 45 degrees to the applied unidirectional tensile load carried by the plate. In this state, the condition of loading is mixed mode. In the first step, behavior of the crack repaired by the composite patch under the applied tensile load is simulated by using ABAQUS commercial software. The crack growth process is modeled with the extended finite element method (XFEM) and the cohesive zone model (CZM) is used to model any damage progression in the adhesive of the composite patch repair. The shape of the five layer composite patch is assumed to be elliptical. For design optimization, the... 

Salicylate selective electrodes based on oxo(phthalocyanato)-vanadium(IV) [VO(Pc), vanadyl phthalocyanine] and oxo(phthalocyanato)molybdenum(IV) [MoO(Pc), molybdenyl phthalocyanine] are described. The electrodes were prepared by incorporating the ionophores into plasticized poly(vinyl chloride) membranes, which were directly coated on the surface of graphite electrodes. The resulting electrodes demonstrate Nernstian responses over a wide linear range (10-7-10-1 M) salicylate. The electrodes have a fast response time, submicromolar detection limit, and could be used over the pH range of 6-9. The proposed sensors revealed selectivity for salicylate over a number of common inorganic and organic... 

The dynamic and static softening phenomena in Al-6Mg alloy were studied through interrupted two-stage hot compression test performed isothermally at 480°C and strain rate range of 0.001-0.1 s-1. The interruptions of 29 and 90 s were considered when the true strain reached 0.5. It was concluded that the effect of static softening on the flow stress was not highlighted by extending the interruption at a constant strain rate. Also, it was exhibited that softening rate highly enhanced with the strain rate decrement at a constant time. Moreover, the static and dynamic recrystallization was revealed as the dominant softening mechanisms at low and high strain rates, respectively  

Almost all existing multi-description coding (MDC) schemes are designed for media streaming over Internet. In this work, a wavelet-based video MDC technique is introduced that fits the criteria of media streaming over peer-to-peer networks. Our proposed method assigns descriptions to the senders due to their characteristic (i.e. bandwidth and availability). In contrast to traditional MDC, different descriptions in the proposed method have different importance in remaking the original media. Our simulation results show considerable improvement of video quality at the receiver (up to 10 dB) as compared to the state-of-the-art. ©2007 IEEE  

Due to the constraints of P2P networks (such as bandwidth limitation) multiple senders should be employed for reliable multimedia streaming. This paper introduces a mathematic approach to select a set of senders among all available senders to provide the most reliable stream for the receiver. This selection is based on upload bandwidths and availability of peers as well as bandwidth of links connecting the senders and the receiver. Our method is called IPROMISE as it is an improved version of the PROMISE algorithm. Simulation results demonstrate improved media quality delivered to the receiver, while the complexity of sender selection remains the same. © 2007 IEEE  

Unlike those on Internet, the media providers on P2P networks are ordinary nodes whose contribution bandwidth is limited. Multi-sender methods are the best solutions known to video streaming on P2P networks. In this paper, we propose use of a multi-cast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. That is while the existing multi-sender methods maximize the bit-rate delivered to the first receiver and cannot provide acceptable bit-rates to the next requesting nodes. © 2006 IEEE  

Due to special constraints in peer-to-peer (P2P) networks (such as bandwidth limitation) and because of their highly dynamic characteristics, a single node cannot provide a reliable multimedia stream to the receivers. Several multi-sender algorithms are proposed to reliably deliver a media stream to the receiver through the intrinsically unreliable P2P networks. Based on upload bandwidths and availability of peers as well as the bandwidths of the links connecting the senders and the receiver, PROMISE selects a set of active senders to maximize the expected bit-rate delivered to the receiver. By careful investigation of PROMISE, in this paper, we present why and how it deviates from finding... 

Unlike those on Internet, the media providers on P2P networks are ordinary nodes with limited shared resources such as bandwidth. Multi-sender methods are the best existing solutions to video streaming on P2P networks. In this paper, we propose use of a multicast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. Experimental results, derived from implementation of the proposed algorithm on Pastry P2P network confirm our claim. Another advantage of our method over the existing methods is its scalability with the number of receivers. © 2007 Elsevier B.V. All rights reserved  

The biophysical and ultrasonographic properties of the skin change in papulosquamous diseases. Aims: To identify biophysical and ultrasonographic properties for the differentiation of five main groups of papulosquamous skin diseases. Methods: Fifteen biophysical and ultrasonographic parameters were measured by multiprobe adapter system and high-frequency ultrasonography in active lesions and normal control skin in patients with chronic eczema, psoriasis, lichen planus, pityriasis rosea and parapsoriasis/mycosis fungoides. Using histological diagnosis as a gold standard, a decision tree analysis was performed based on the mean percentage changes of these parameters [(lesion-control/control)... 

Unlike those on Internet, the media providers on P2P networks are ordinary nodes with limited shared resources such as bandwidth. Multi-sender methods are the best existing solutions to video streaming on P2P networks. In this paper, we propose use of a multicast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. Experimental results, derived from implementation of the proposed algorithm on Pastry P2P network confirm our claim. Another advantage of our method over the existing methods is its scalability with the number of receivers  

Developing heterogeneous catalysts with high performance for peroxymonosulfate (PMS) activation to decontaminate organic pollutants from wastewater is of prominent importance. In this study, spinel cobalt ferrite (CoFe2O4) materials were coated on the surface of powdered activated carbon (CoFe2O4@PAC) via the facile co-precipitation method. The high specific surface area of PAC was beneficial for the adsorption of both bisphenol A (BP-A) and PMS molecules. The CoFe2O4@PAC-mediated PMS activation process under UV light could effectively eliminate 99.4% of the BP-A within 60 min of reaction. A significant synergy effect was attained between CoFe2O4 and PAC towards PMS activation and subsequent... 

In this case–control study, class І and ІІ human leukocyte antigen (HLA) alleles in Iranian patients with benign and severe cutaneous adverse drug reactions (CADRs) due to aromatic anticonvulsants and antibiotics were evaluated. Patients diagnosed with CADRs (based on clinical and laboratory findings) with a Naranjo score of ≥ 4 underwent blood sampling and HLA-DNA typing. The control group comprised 90 healthy Iranian adults. Alleles with a frequency of more than two were reported. Deviations from Hardy–Weinberg equilibrium were not observed. Eighty patients with CADRs including 54 females and 26 males with a mean age of 41.49 ± 16.08 years were enrolled in this study. The culprit drugs...