Sharing spray and wait routing algorithm in opportunistic networks

Due to the instability and intermittent connectivity of links among the nodes and the lack of connectivity in opportunistic network, it is not feasible to use common routing for delivering messages. The only practical method for routing and delivering messages is to use the store-carry-forward routing method. As a case in point, spray and wait is considered to be one of the most appropriate routing methods. The efficiency of this method depends directly on the proper selection of the next hop and the number of copies when it encounters a node. In this paper, a method was proposed that constantly selects the next node and considers the number of copies a node can deliver. In the proposed method, the selection of the next node and the number of message copies to be transmitted by the next hop are based on message carrying time and the probability of message delivery. The network model, based on Markov chain, is extended for analysis. Simulation and analysis results showed that significant enhancement is obtained with the proposed method when measuring metrics such as delay, delivery ratio and copy do comparisons with similar methods.     

Experimental investigation into Fe3O4/SiO2 nanoparticle performance and comparison with other nanofluids in enhanced oil recovery

Nanofluids because of their surface characteristics improve the oil production from reservoirs by enabling different enhanced recovery mechanisms such as wettability alteration, interfacial tension (IFT) reduction, oil viscosity reduction, formation and stabilization of colloidal systems and the decrease in the asphaltene precipitation. To the best of the authors’ knowledge, the synthesis of a new nanocomposite has been studied in this paper for the first time. It consists of nanoparticles of both SiO₂ and Fe₃O₄. Each nanoparticle has its individual surface property and has its distinct effect on the oil production of reservoirs. According to the previous studies, Fe₃O₄ has been used in the prevention or reduction of asphaltene precipitation and SiO₂ has been considered for wettability alteration and/or reducing IFTs in enhanced oil recovery. According to the experimental results, the novel synthesized nanoparticles have increased the oil recovery by the synergistic effects of the formed particles markedly by activating the various mechanisms relative to the use of each of the nanoparticles in the micromodel individually. According to the results obtained for the use of this nanocomposite, understanding reservoir conditions plays an important role in the ultimate goal of enhancing oil recovery and the formation of stable emulsions plays an important role in oil recovery using this method.     

Highly Efficient Quasi 2D Blue Perovskite Electroluminescence Leveraging a Dual Ligand Composition

Perovskite light-emitting diodes (PeLEDs) are advancing because of their superior external quantum efficiencies (EQEs) and color purity. Still, additional work is needed for blue PeLEDs to achieve the same benchmarks as the other visible colors. This study demonstrates an extremely efficient blue PeLED with a 488 nm peak emission, a maximum luminance of 8600 cd m⁻², and a maximum EQE of 12.2% by incorporating the double-sided ethane-1,2-diammonium bromide (EDBr₂) ligand salt along with the long-chain ligand methylphenylammonium chloride (MeCl). The EDBr₂ successfully improves the interaction between 2D perovskite layers by reducing the weak van der Waals interaction and creating a Dion–Jacobson (DJ) structure. Whereas the pristine sample (without EDBr₂) is inhibited by small stacking number (n) 2D phases with nonradiative recombination regions that diminish the PeLED performance, adding EDBr₂ successfully enables better energy transfer from small n phases to larger n phases. As evidenced by photoluminescence (PL), scanning electron microscopy (SEM), and atomic force microscopy (AFM) characterization, EDBr₂ improves the morphology by reduction of pinholes and passivation of defects, subsequently improving the efficiencies and operational lifetimes of quasi-2D blue PeLEDs.     

在新兴便携式应用中集成Li-xx充电管理元件

新兴的便携式产品在提高功能与性能的同时，体积变得越来越小巧。因此，OEM 厂商希望能够缩小包括电池充电管理等电源管理功能所需要的空间。本文将探讨高度集成充电控制元件带来的挑战及优势，同时将详细说明该领域中的最新产品与 IC 组件。充电控制中的3“C”充电控制与管理是所有采用了可充电电池的便携式设计中的关键功能。先进的设计技术需确保满足以下3项关键要求。电池安全 (Cell Safety)此项要求不单单限于满足电池制造商建议的、在充电最后阶段±1%的电压调整容限要求，而且还包含了其他功能，如：可安全处理深放电电池的预处…     

Cholesterol and fat contents of Spanish commercial pork cuts

A study was carried out to determine the fat and cholesterol contents of several commercial pork cuts as function of sex. Fat and cholesterol content ranged from 2.7% and 57 mg/100 g in loin to 30.3% and 116 mg/100 g in dewlap. The higher the fat content the higher was the cholesterol content. Sex did not influence fat content and the fat/cholesterol ratio, but cholesterol content was higher in females than in males.     

A new design of optical add/drop filters and multi-channel filters based on hexagonal PhCRR for WDM systems

Photonic Network Communications - In this research, using photonic crystal dielectric rods with a triangular lattice constant, a photonic crystal ring resonator (PhCRR) has been designed in order...     

Virtual Machine Consolidation in Cloud Computing Systems: Challenges and Future Trends

Wireless Personal Communications - Cloud Computing Systems (CCSs) provides a computing capability through the Internet. It enables organizations or individuals to have a computing power without...     

A 0.5–1 GHz single stage linear-in-decibel VGA with 80 dB gain range in 0.18 μm CMOS

Communication systems require a wide gain range. For example the code-division multiple access system (CDMA) requires more than 80 dB of gain range so that, many variable gain amplifiers (VGAs) must be used, resulting in high power consumption and low linearity because of VGA non-linearity factors. In this paper, a one-stage VGA in 0.18 μm technology is presented. The VGA based on the class AB power amplifier is designed and simulated for a high linearity and an 80 dB tuning range. For the linear-in-decibel tuning range, transistors in sub-threshold region is used. The current control circuit of the VGA changes gain continuously from ?68 to 18 dB at 0.5 GHz and ?60 to 20 dB at 1 GHz with gain error of less than 2 dB. The power consumption enjoys a highest value about 13.5 mW in the maximum gain and P1dB is also about ?3.4 dBm at 0.5 GHz and 2.2 dBm at 1 GHz.     

Pricing mechanism for interconnection between phone operators and virtual mobile VoIP operators

Lately software based virtual mobile voice over Internet Protocol (VMVoIP) services have become available to end-users which may endanger profit of regular telephone operators from phone calls. In this situation, telephone operators should decide on a proper mechanism for interconnection with such VMVoIP operators which secures mutual benefit of both operators. In this paper, we study both monopolistic and oligopolistic markets of VMVoIP in which a single VMVoIP and several VMVoIP operators available in the market respectively. We model the interaction among a phone operator, VMVoIP operators and end-users as a leader-follower dynamic game and find a sub-game perfect Nash equilibrium (SPNE) for the game. The SPNE shows the phone operator’s best pricing strategy (i.e., wholesale price for VMVoIP operators and retail price for end-users) and its best decision on the interconnection with VMVoIP operators. We further study economic interpretation of the SPNE. We show that in specific end-users’ demands, the phone operator may increase its total profit by allowing the interconnection and taking right price discrimination strategy.     

New evolution in two-way relay networks based on physical layer network coding

Telecommunication Systems - In this paper, a physical-layer network coding (PNC) method is offered for a two-way relay network with spatial modulation (SM) for source node and relay node. For this...