An Efficient Anonymous Authentication Scheme Using Registration List in VANETs

Nowadays, Vehicular Ad hoc Networks (VANETs) are popularly known as they can reduce traffic and road accidents. These networks need several security requirements, such as anonymity, data authentication, confidentiality, traceability and cancellation of offending users, unlinkability, integrity, undeniability and access control. Authentication is one of the most important security requirements in these networks. So many authentication schemes have been proposed up to now. One of the well-known techniques to provide users authentication in these networks is the authentication based on the smartcard (ASC). In this paper, we propose an ASC scheme that not only provides necessary security requirements such as anonymity, traceability and unlinkability in the VANETs but also is more efficient than the other schemes in the literatures.Comment: 5 pages, 4 figures, Accepted for ICEE202

A Low Complexity Space-Time Block Codes Detection for Cell-Free Massive MIMO Systems

The new generation of telecommunication systems must provide acceptable data rates and spectral efficiency for new applications. Recently massive MIMO has been introduced as a key technique for the new generation of telecommunication systems. Cell-free massive MIMO system is not segmented into cells. Each BS antennas are distributed throughout the environment and each user is served by all BSs, simultaneously. In this paper, the performance of the multiuser cell-free massive MIMO-system exploying space-time block codes in the uplink, and with linear decoders is studied. An Inverse matrix approximation using Neumann series is proposed to reduce the computational and hardware complexity of the decoding in the receiver. For this purpose, each user has two antennas, and also for improving the diversity gain performance, space-time block codes are used in the uplink. Then, Neumann series is used to approximate the inverse matrix in ZF and MMSE decoders, and its performance is evaluated in terms of BER and spectral efficiency. In addition, we derive lower bound for throughput of ZF decoder. The simulation results show that performance of the system , in terms of BER and spectral efficiency, is better than the single-antenna users at the same system. Also, the BER performance in a given system with the proposed method will be close to the exact method.Comment: 5 pages, 4 figures, Accepted for ICEE202

Ab initio prediction of semiconductivity in a novel two-dimensional Sb2X3 (X= S, Se, Te) monolayers with orthorhombic structure

Sb 2S 3 and Sb 2Se 3 are well-known layered bulk structures with weak van der Waals interactions. In this work we explore the atomic lattice, dynamical stability, electronic and optical properties of Sb 2S 3, Sb 2Se 3 and Sb 2Te 3 monolayers using the density functional theory simulations. Molecular dynamics and phonon dispersion results show the desirable thermal and dynamical stability of studied nanosheets. On the basis of HSE06 and PBE/GGA functionals, we show that all the considered novel monolayers are semiconductors. Using the HSE06 functional the electronic bandgap of Sb 2S 3, Sb 2Se 3 and Sb 2Te 3 monolayers are predicted to be 2.15, 1.35 and 1.37 eV, respectively. Optical simulations show that the first absorption coefficient peak for Sb 2S 3, Sb 2Se 3 and Sb 2Te 3 monolayers along in-plane polarization is suitable for the absorption of the visible and IR range of light. Interestingly, optically anisotropic character along planar directions can be desirable for polarization-sensitive photodetectors. Furthermore, we systematically investigate the electrical transport properties with combined first-principles and Boltzmann transport theory calculations. At optimal doping concentration, we found the considerable larger power factor values of 2.69, 4.91, and 5.45 for hole-doped Sb 2S 3, Sb 2Se 3, and Sb 2Te 3, respectively. This study highlights the bright prospect for the application of Sb 2S 3, Sb 2Se 3 and Sb 2Te 3 nanosheets in novel electronic, optical and energy conversion systems. © 2021, The Author(s)

Paleoearthquakes and slip rates of the North Tabriz Fault, NW Iran: preliminary results

The North Tabriz Fault is a major seismogenic fault in NW Iran. The last damaging earthquakes on this fault occurred in 1721, rupturing the southeastern fault segment, and in 1780, rupturing the northwestern one. The understanding of the seismic behavior of this fault is critical for assessing the hazard in Tabriz, one of the major cities of Iran; the city suffered major damage in both the 1721 and 1780 events. Our study area is located on the northwestern fault segment, west of the city of Tabriz. We performed geomorphic and trenching investigations, which allowed us to recognize evidence for repeated faulting events since the Late Pleistocene. From the trenches, we found evidence for at least four events during the past 3.6 ka, the most recent one being the 1780 earthquake. On the basis of different approaches, horizontal slip per event and slip rates are found in the ranges of 4 ± 0.5 m and 3.1-6.4 mm/yr, respectively. We also attempted an estimate of the average recurrence intervals which appears to be in the range 350-1430 years, with a mean recurrence interval of 821 ± 176 years. On the basis of these results, the northwestern segment of the North Tabriz Fault does not appear to present a major seismic potential for the near future, however, not enough is known about the southeastern segment of the fault to make a comparable conclusion

Analysis of sand dunes to determine wind direction and detect sand source sites (case study: Khartooran Erg, Iran)

Wind regime and sand grain size are two of the factors that determine the morphology and dynamics of sand dunes in desert areas. Regarding the importance of wind effects on sand dunes especially in Iran, in this study, Khartooran Erg was analyzed to determine wind direction and to detect sand source sites. Khartooran Erg is located on eastern north of Iran and lies in Khorasan Razavi and Semnan provinces. The area of Erg was determined based on geological and topographical maps and satellite images. Then, sand dunes of erg were classified, based on aerial photograph and satellite image interpretation. Sand dune forms in the Khartooran Erg are often barchans and combination of barchanic ridges, but there are also complex types of linear sand dunes. Based on field survey findings, the stabilized in the southern part of the Erg were separated, because of these sand dunes having been deformed. According to the presented models relationship between morphology and wind direction, the sand dunes were analyzed. The studies have shown that wind prevailing direction is eastern-north to western-south, the strong wind being in north-south direction. It can also be said that sand dunes which are located in the adjacent of Erg and are simple and separate can be used as the most suitable criteria to determine predominant wind. Also, regarding the Erg location with respect to upper plains and determined wind direction, it can be noted that sand sources mostly come from silt-clay flats of ending parts of Sabzevar Kal River rather than Jajarm Kal River

Platelet clearance via shear-induced unfolding of a membrane mechanoreceptor

Mechanisms by which blood cells sense shear stress are poorly characterized. In platelets, glycoprotein (GP)Ib-IX receptor complex has been long suggested to be a shear sensor and receptor. Recently, a relatively unstable and mechanosensitive domain in the GPIba subunit of GPIb-IX was identified. Here we show that binding of its ligand, von Willebrand factor, under physiological shear stress induces unfolding of this mechanosensory domain (MSD) on the platelet surface. The unfolded MSD, particularly the juxtamembrane € Trigger' sequence therein, leads to intracellular signalling and rapid platelet clearance. These results illustrate the initial molecular event underlying platelet shear sensing and provide a mechanism linking GPIb-IX to platelet clearance. Our results have implications on the mechanism of platelet activation, and on the pathophysiology of von Willebrand disease and related thrombocytopenic disorders. The mechanosensation via receptor unfolding may be applicable for many other cell adhesion receptors

DESIGN OF MAGNETIC BPM AND ERROR CORRECTIONS*

Abstract For beam position monitoring (BPM) purposes, two prominent approaches as a physical effect have been applied including electrostatic and magnetic. In electrostatic types, secondary emission from the electrodes can be a problem when strong beam loss occurs, in such a situation, a magnetic BPM may be chosen. For this purpose we made a magnetic BPM including a square shape of polyethylene core with winding on each side. In this case study we used it for detecting the position of wire which is including a pulsed current (as an electron bunch) produced by a PROTEK G305 pulse generator. A Tektronix 2235A oscilloscope was calibrated and used to measure the induced voltage of magnetic BPM. Measurement results have been compared with simulation using CST software and performed error corrections which are presented, with this regard we could measure the wire position with high resolution furthermore we deduced the wire position hasn't linear relation with induced voltage and needs more physical and mathematical analyzing. This way propose us that we can use magnetic BPMs in this approach and calibrate them before installing on accelerator