Improving the Reliability of Software-Defined Networks with Distributed Controllers Through Leader Election Algorithm and Colored Petri-Net

Wireless Personal Communications - Software-Defined Networks (SDNs) are developed to compensate the complicated function of the controlling parts of the given network elements and making the...     

Correction to: Cloud-based vehicular networks: a taxonomy,survey, and conceptual hybrid architecture

Wireless Networks - The original version of this article unfortunately contained a mistake in the title. The correct title has been published with this erratum.     

Comparative study of maximum power point tracking techniques for hybrid renewable energy system

The power generation demand is increasing day-by-day throughout the world, therefore, the use of hybrid systems becomes a significant solution. The hybrid renewable energy system (HRES) is used for delivering power in various regions in order to overcome intermittence of wind and solar resources. Because of increasing environmental problems, for example, greenhouse gas emission and energy cost have interested novel research into substitute methods in favour of electrical power generation. Maximum Power Point Tracking (MPPT) control method is a vast deal of novel research used for enhancing the efficiency of HRES. The authors have revealed that the hybrid techniques i.e. Global MPPT, fuzzy-neuro systems, Adaptive Neuro-Fuzzy Inference System (ANFIS), Perturbed and Observe (P&O) + Adaptive Neural Network (ANN) etc. can provide best results as compared to other MPPT control methods. This paper offering a state of art review of MPPT control techniques for HRES.     

Proposal for st-Routing Protocol

A routing protocol chooses one of the several paths (routes) from a source node to a destination node in the computer network, to send a packet of information. In this paper, we propose a new routing protocol, which we call st-routing protocol, based on st-numbering of a graph. The protocol fits well in noisy environments where robustness of routing using alternative paths is a major issue. The proposed routing protocol provides a systematic way to retry alternative paths without generating any duplicate packets. The protocol works for only those networks that can be represented by biconnected graphs.     

Progress and prospects of group-III nitride semiconductors

We review recent progress in the group-III nitride and related materials, and electronic and optical devices based on them. Blue and UV (e.g. ultra violet) emitters and detectors, and high temperature/high power electronics which has long been coveted are beginning to be realized either in the laboratory or in the commercial arena, due in part to the breathtaking progress made in the last few years in the art and science of GaN, InN, AlN and their salloys. With brief references to the historical aspect of the relevant developments, this review concerns itself primarily with the current status of wide bandgap gallium nitride and related semiconductors from both the materials and devices points of view. Following a discussion of the structural properties of these materials, their electrical and optical properties are described in detail. The available data on metal contacts, the properties of which are indeed very conducive for the devices mentioned, from the points of view of ohmic contacts and Schottky barriers, are elaborated on. Recent progress on processing issues such as etching are reviewed. The review then embarks on an indash;depth discussion and analysis of field effect transistors, bipolar transistors, light emitting diodes, laser and photo detectors.     

The potential for greenhouse gases mitigation in household sector of Iran: cases of price reform/efficiency improvement and scenario for 2000–2010

Iran's demographic profile is sharply youth oriented and this upcoming generation's needs for employment and housing, coupled with low-energy efficiency vectors and consumption patterns, has created a constant rise in energy demand and greenhouse gas (GHGs) emissions in the residential sector. Improved energy efficiency as a national policy lynchpin for demand reduction and GHGs mitigation, has become commonplace. OPEC countries however, Iran included, suffer an obvious lack of consumer incentive because of low fuel prices. This study evaluates the twin impacts of price reform and efficiency programs on energy carriers’ consumption and GHGs mitigation in the Iranian housing sector. For this purpose, the demand functions for energy carriers, has been developed by econometrics process models.     

A critical review of Iran''s buyback contracts

Iran's oil and gas industry requires investments of US$ 15 billion in the short term and over US$70 billion in the medium term. Iran tries to interest international oil companies (IOC) in investing in Iran's oil and gas business by offering buyback contracts. Under a buyback contract an IOC invests and when production starts, the field is handed over to the National Iranian Oil Company (NIOC) or one of its representatives. The IOC gets its costs and an agreed upon profit paid out of the oil and/or gas gross profits, assuming the field produces as agreed upon and the international energy prices are high enough. According to the Iranian government, the buyback contract contains sufficient incentives for an IOC to invest in Iran. The IOCs, however, disagree. They claim that they solely bare the risks in a buyback contract, whereas the Iranian counterpart receives all windfall profits. Furthermore, the IOCs claim that the utilisation of Iran's oil and gas reserves will be sub-optimal if they are not involved in optimising long-term recovery. In this paper, we investigate these claims and show that they are partly correct. Given Iran's need for investment capital, Iran might have to change its policy.     

Optimization of Output Power and Thermal Efficiency of Solar‐Dish Stirling Engine Using Finite Time Thermodynamic Analysis

This paper presents an investigation on finite time thermodynamic (FTT) evaluation of a solar‐dish Stirling heat engine. FTTs has been applied to determine the output power and the corresponding thermal efficiency, exergetic efficiency, and the rate of entropy generation of a solar Stirling system with a finite rate of heat transfer, regenerative heat loss, conductive thermal bridging loss, and finite regeneration process time. Further imperfect performance of the dish collector and convective/radiative heat transfer mechanisms in the hot end as well as the convective heat transfer in the heat sink of the engine are considered in the developed model. The output power of the engine is maximized while the highest temperature of the engine is considered as a design parameter. In addition, thermal efficiency, exergetic efficiency, and the rate of entropy generation corresponding to the optimum value of the output power is evaluated. Results imply that the optimized absorber temperature is some where between 850 K and 1000 K. Sensitivity of results against variations of the system parameters are studied in detail. The present analysis provides a good theoretical guidance for the designing of dish collectors and operating the Stirling heat engine system.     

A Molecular Dynamics Study of Description Models for Shear Viscosity in Nanochannels: Mixtures and Effect of Temperature

Equilibrium molecular dynamics simulation was utilized to calculate the shear viscosity of monoatomic molecules liquid flow confined in a nanochannel in the pure state and their binary mixtures. The pure flow viscosity data of argon, krypton, and xenon were used to predict their binary mixture viscosities using prediction methods proposed in the literature. Each method was evaluated by comparison of its results with those obtained by validated molecular dynamics simulation at different temperatures. In addition, correlative methods for mixture viscosity estimation and temperature dependence models were evaluated and corresponding model parameters were obtained. Moreover, the relations representing mixture parameter values as a function of the pure ones were determined and evaluated according to their accuracy.