Simulation and Experimental Studies of Illumination Effects on the Current Transport of Nitridated GaAs Schottky Diode

Semiconductors - In this paper, we studied the electrical characteristic of Schottky diodes based on gold contact on nitridated GaAs substrates. The used (100) GaAs substrate is n-type with...     

Reliable and Adaptive Distributed Public-Key Management Infrastructure for the Internet of Things

Wireless Personal Communications - The Internet of Things (IoT) is an emerging paradigm in the world of computer networks, where physical objects are connected over the Internet. Given the huge...     

Decomposing global solar radiation into its diffuse and direct normal radiation

ABSTRACT

This work presents a model based on Radial Basis Function (RBF) to estimate the diffused solar radiation (DSR) and direct normal radiation (DNR) fractions of solar radiation from global solar radiation in a semiarid area in Algeria based on a database measured between 2013 and 2015. The data has been collected at Applied Research Unit for Renewable Energies, (URAER) at Ghardaia city situated in the south of Algeria. The experimental results show that RBF model estimates DNR and DSR with high performance. The difference between the measured and the predicted values show a normalised Root Mean Square Error (nRMSE) of 0.033 and 0.065 for DNR and DSR, respectively. The obtained values of Determination Coefficient (R²) and Correlation Coefficient (R) are: 97.3%, 98.60%, respectively for DNR and 88.89%, 91.12% For DSR.

However, the obtained results are very plausible and showed that RBF model estimates the DSR and DNR with good accuracy.     

Reliable and fully distributed trust model for mobile ad hoc networks

A mobile ad hoc network (MANET) is a wireless communication network which does not rely on a pre-existing infrastructure or any centralized management. Securing the exchanges in MANETs is compulsory to guarantee a widespread development of services for this kind of networks. The deployment of any security policy requires the definition of a trust model that defines who trusts who and how. Our work aims to provide a fully distributed trust model for mobile ad hoc networks. In this paper, we propose a fully distributed public key certificate management system based on trust graphs and threshold cryptography. It permits users to issue public key certificates, and to perform authentication via certificates' chains without any centralized management or trusted authorities. Moreover, thanks to the use of threshold cryptography; our system resists against false public keys certification. We perform an overall evaluation of our proposed approach through simulations. The results indicate out performance of our approach while providing effective security.     

Soft computing for solar radiation potential assessment in Algeria

ABSTRACT

Precise estimation of solar radiation is a highly required parameter for the design and assessment of solar energy applications. Over the past years, many machine learning techniques have been proposed in order to improve the forecasting performance using different input attributes. The aim of this study is the forecasting of one day ahead of horizontal global solar radiation using a set of meteorological and geographical inputs. In this respect, the Gaussian process regression methodology (GPR) and least-square support vector machine (LS-SVM) with different kernels are evaluated in order to select the most appropriate forecasting model. In order to assess the proposed models, the southern Algerian city, Ghardaia regions, was selected for this study. A historical data of five years (2013–2017) of meteorological data collected at Renewable Energies (URAER) in Ghardaia city are used. The achieved results demonstrate that all the proposed models give approximately similar results in terms of statistical indicators. In term of processing time, all the models showed acceptable computational efficiency with less computational costs of the GPR model among all machine learning models.     

Context-aware negotiation,reputation and priority traffic light management protocols for VANET-based smart cities

Telecommunication Systems - The traditional transportation system is based on a fixed-timed strategy to control the traffic congestion on urban roads. However, the increase of vehicle density in a...     

Certification-based trust models in mobile ad hoc networks: A survey and taxonomy

A mobile ad hoc network is a wireless communication network which does not rely on a pre-existing infrastructure or any centralized management. Securing the exchanges in such network is compulsory to guarantee a widespread development of services for this kind of networks. The deployment of any security policy requires the definition of a trust model that defines who trusts who and how. There is a host of research efforts in trust models framework to securing mobile ad hoc networks. The majority of well-known approaches is based on public-key certificates, and gave birth to miscellaneous trust models ranging from centralized models to web-of-trust and distributed certificate authorities. In this paper, we survey and classify the existing trust models that are based on public-key certificates proposed for mobile ad hoc networks, and then we discuss and compare them with respect to some relevant criteria. Also, we have developed analysis and comparison among trust models using stochastic Petri nets in order to measure the performance of each one with what relates to the certification service availability.     

Multi-step-ahead forecasting of daily solar radiation components in the Saharan climate

ABSTRACT

Accurate estimation of renewable energy sources plays an important role in their integration into the grid. An unexpected atmospheric change can produce a range of problems related to various solar plant components affecting the electricity generation system. Global solar radiation (GSR) assessment has been increased in the past decade due to its important use in photovoltaic application. In this paper, we propose the use of machine learning-based models for daily global and direct solar radiation forecasting in a semi-arid climate, using a combination set of meteorological parameters on a horizontal surface in the Ghardaïa region. The models are presented and implemented on 3-year measured meteorological data at Applied Research Unit for Renewable Energies (URAER) at Ghardaïa city between 2014 and 2016. The results show that both MLP and RBF models perform well for three-step-ahead forecasting with a slight improvement in MLP models in terms of statistical metrics.     

Secure and distributed certification system architecture for safety message authentication in VANET

Vehicular Ad hoc NETworks (VANETs) are a burgeoning research focus, aimed at creating communication among vehicles to improve the road safety and enhance driving conditions. For such networks, security is one of the most challenging issues due to their nature of wireless transmission and high topology changing frequency. In this paper, we propose a secure and distributed certification system architecture for safety message authentication in VANET, which resists against false public-key certification. To increase the availability of the authentication service, our proposal is designed through a decentralized system, supervised by a root authority. The latter authority delegates to a set of regional certification authorities the privilege of issuing public-key certificates to the vehicles. Each regional certification authority cooperates with its subordinates RSUs to sign public-key certificates using threshold signature. The main purpose of our solution is to ensure the messages authentication while respecting the imposed constraints by the real-time aspect and the nodes mobility. We demonstrate through the practical analysis and simulation results the efficiency of our solution with comparison to other concurrent protocols.