Mohammad Hossein Ahmadi

Mohammad Hossein Ahmadi, Alireza Baghban, Milad Sadeghzadeh et al.

Solar energy is a renewable resource of energy that is broadly utilized and has the least emissions among renewable energies. In this study, machine learning methods of artificial neural networks (ANNs), least squares support vector machines (LSSVM), and neuro-fuzzy are used for advancing prediction models for the thermal performance of a photovoltaic-thermal solar collector (PV/T). In the proposed models, the inlet temperature, flow rate, heat, solar radiation, and the sun heat have been considered as the inputs variables. Data set has been extracted through experimental measurements from a novel solar collector system. Different analyses are performed to examine the credibility of the introduced approaches and evaluate their performance. The proposed LSSVM model outperformed ANFIS and ANNs models. LSSVM model is reported suitable when the laboratory measurements are costly and time-consuming, or achieving such values requires sophisticated interpretations.

Mohammad Ahmadi, Mostafa Vali, Farez Moghaddam et al.

Security issues are the most challenging problems in cloud computing environments as an emerging technology. Regarding to this importance, an efficient and reliable user authentication and data protection model has been presented in this paper to increase the rate of reliability cloud-based environments. Accordingly, two encryption procedures have been established in an independent middleware (Agent) to perform the process of user authentication, access control, and data protection in cloud servers. AES has been used as a symmetric cryptography algorithm in cloud servers and RSA has been used as an asymmetric cryptography algorithm in Agent servers. The theoretical evaluation of the proposed model shows that the ability of resistance in face with possible attacks and unpredictable events has been enhanced considerably in comparison with similar models because of using dual encryption and an independent middleware during user authentication and data protection procedures.