Anonymous TollPass: A Blockchain-Based Privacy-Preserving Electronic Toll Payment Model

As big data,Artificial Intelligence,and Vehicle-to-Everything(V2X)communication have advanced,Intelligent Transportation Systems(ITS)are being developed to enable efficient and safe transportation systems.Electronic Toll Collection(ETC),which is one of the services included in ITS systems,is an automated system that allows vehicles to pass through toll plazas without stopping for manual payment.The ETC system is widely deployed on highways due to its contribution to stabilizing the overall traffic system flow.To ensure secure and efficient toll payments,designing a distributed model for sharing toll payment information among untrusted toll service providers is necessary.However,the current ETC system operates under a centralized model.Additionally,both toll service providers and toll plazas know the toll usage history of vehicles.It raises concerns about revealing the entire driving routes and patterns of vehicles.To address these issues,blockchain technology,suitable for secure data management and data sharing in distributed systems,is being applied to the ETC system.Blockchain enables efficient and transparent management of ETC information.Nevertheless,the public nature of blockchain poses a challenge where users’usage records are exposed to all participants.To tackle this,we propose a blockchain-based toll ticket model named AnonymousTollPass that considers the privacy of vehicles.The proposed model utilizes traceable ring signatures to provide unlinkability between tickets used by a vehicle and prevent the identity of the vehicle using the ticket from being identified among the ring members for the ticket.Furthermore,malicious vehicles’identities can be traced when they attempt to reuse tickets.By conducting simulations,we show the effectiveness of the proposed model and demonstrate that gas fees required for executing the proposed smart contracts are only 10%(when the ring size is 50)of the fees required in previous studies.

Particle-in-Cell Simulation Study on the Floating Potential of Spacecraft in the Low Earth Orbit

In order to further understand the characteristics of the floating potential of low earth orbit spacecraft,the effects of the electron current collection area,background electron temperature,photocurrent emission,spacecraft wake,and the shape of spacecraft on spacecraft floating potential were studied here by particle-in-cell simulation in the low earth orbit.The simulation results show that the electron current collection area and background electron temperature impact on the floating potential by changing the electron current collection of spacecraft.By increasing the electron current collection area or background electron temperature,the spacecraft will float at a lower electric potential with respect to the surrounding plasma.However,the spacecraft wake affects the floating potential by increasing the ion current collected by spacecraft.The emission of the photocurrent from the spacecraft surface,which compensates for the electrons collected from background plasma,causes the floating potential to increase.The shape of the spacecraft is also an important factor influencing the floating potential.

A 2.1 μA WAKE-UP CIRCUIT FOR CHINESE ETC SYSTEM

This paper proposes a low power wake-up baseband circuit used in Chinese Electronic Toll Collection (ETC) system. To reduce the static power consumption, a low power biasing strategy is proposed. The proposed circuit is fabricated in TSMC 0.18 μm technology with an area of 0.09 mm 2 . Its current consumption is only 2.1 μA under 1.8 V power supply. It achieves a sensitivity of 0.95 mV at room temperature with a variation of only ±28% over -35℃ to 105℃.

Propagation of Ion Solitary Pulses in Dense Astrophysical Electron-Positron-Ion Magnetoplasmas

In this paper,we theoretically investigate the existence and propagation of low amplitude nonlinear ion waves in a dense plasma under the influence of a strong magnetic field.The plasma consists of ultra-relativistic and degenerate electrons and positrons and non-degenerate cold ions.Firstly,the appearance of two distinct linear modes and their evolution is studied by deriving a dispersion equation with the aid of Fourier analysis.Secondly,the dynamics of low amplitude ion solitary structures is investigated via a Korteweg-de Vries equation derived by employing a reductive perturbation method.The effects of various plasma parameters like positron concentration,strength of magnetic field,obliqueness of field,etc.,are discussed in detail.At the end,analytical results are supplemented through numerical analysis by using typical representative parameters consistent with degenerate and ultra-relativistic magnetoplasmas of astrophysical regimes.

High-efficient electron collection capability of graded Al compositional GaN nanowire arrays cathode

Based on the purpose of solving the"secondary absorption"of adjacent nanowires and the lateral emission in the Ga N nanowire arrays(NWAs)cathode,an exponential-doping and graded Al compositional Ga N NWAs photocathode is proposed,which could generate internal electric field to increase the quantum efficiency(QE)of top surface,and the introduction of an external electric field promote the side-emission electrons to shift toward the collecting side.The QE and collection efficiency(CE)of exponential-doping and graded compositional Ga N NWAs under different array structure parameters,incident angles and external electric field intensities are analyzed.The results show that although the collection ratio of emitted electrons in the exponential-doping Ga N NWAs is higher,the graded Al compositional photocathode with a stronger built-in electric field can obtain better CE under the application of an external electric field,and the peak value can reach 33.2%in a specific structure.External electric field has a more significant effect on the CE of uniform-doping Ga N NWAs.The solutions provided in this study can make the Ga N NWAs photocathode more suitable for the strict requirements of vacuum electron sources.

Ultrathin ALD coating on TiO_2 photoanodes with enhanced quantum dot loading and charge collection in quantum dots sensitized solar cells

TiO_2 nanocrystals are widely used in photoanodes for quantum dot solar cells(QDSCs) owing to their chemical stability and suitable energy band structure.However, surface defects and grain boundaries of TiO_2 nanocrystals photoanodes allow high surface charge recombination,which limits the performance of QDSCs. In this work, an ultrathin TiO_2 layer is introduced to the surface of TiO_2 photoanodes by atomic layer deposition(ALD).The ultrathin layer not only reduces the surface defects of TiO_2 nanoparticles and strengthens the connection between adjacent nanoparticles to suppress the charge recombination for improving the electron collection efficiency(ηcc), but also increases the surface energy of photoanodes to load more quantum dots(QDs) for enhancing the light harvesting efficiency(LHE). As a result, the solar cell based on CdS/CdSe QDs with ALD treatment exhibits an efficiency of 5.07% that is much higher than that of the cells without modification(4.03%).

Improved electron capture capability of field-assisted exponential-doping GaN nanowire array photocathode

The exponential-doping GaN nanowire arrays(GaN NWAs)photocathode has a"light-trapping effect",and the built-in electric field can promote the concentration of the photogene rated carrier center to the top surface of the nanowire.However,in the preparation ofactual NWAs photocathodes,the problem that photons emitted from the sides of the nanowires cannot be effectively collected has been encountered.Our proposed field-assisted exponential-doping GaN NWAs can bend the motion trajectory of the emitted electrons toward the collecting side.In this study,the quantum efficiency(QE)and collection efficiency(CE)of the external field-assisted exponential-doping GaN NWAs photocathode are derived based on the two-dimensional carrier diffusion equation and the initial energy and angular distribution,respectively.For a field-assisted exponential-doping GaN NWAs with a width d=200 nm and a height H=400 nm,the optimal structural parameters are obtained:the incident angleθ=50°and the nanowire spacing is L=335.6 nm.On this basis,the field intensity of 0.5 V/μm can maximize the CE of the NWAs.All the results show that the field-assisted approach does contribute to the collection of emitted electrons,which can provide theoretical guidance for high-performance electron sources based on exponential-doping GaN NWAs photocathodes.And field-assisted exponential-doping GaN NWAs cathode is expected to be verified by the experimental results in the future.

Synergistic effect of TiO_2 hierarchical submicrospheres for high performance dye-sensitized solar cells

The performance of dye-sensitized solar cells(DSCs) could be improved by using rationally designed mesoporous film structure for electron collection, dye adsorption and light scattering. The development of a novel double layer film prepared by TiO_2 hierarchical submicrospheres and nanoparticles was reported in this article. The submicrospheres were composed of rutile nanorods of 10 nm diameter and the length of 150–250 nm, which facilitated fast electron transport, charge collection and light scattering. Using a double layer structure consisting of the 10 wt% film as a dye loading layer and the 50 wt% film as the light scattering layer, C101 sensitizer and liquid electrolyte, DSC yielded power conversion efficiency of 9.68% under 1 sun illumination.