Bismuth Oxide Thin Films for Optoelectronic and Humidity Sensing Applications

Bismuth oxide thin films still prove attractive to both scientists and engineers due to their semiconducting behavior, large energy bandgap and high refractive index, despite their often complex structure, both polymorphic and polycrystalline. We present here a summary and a comparison of the morpho-structural and optical properties of such films prepared through three physical vapor deposition (PVD) techniques on several types of substrates kept at different temperatures. Thermal vapor deposition, thermal oxidation in air and pulsed laser deposition are discussed as largely used PVD methods. It is proved that the physical properties of the bismuth oxide thin films can be tailored by changing the substrate nature and its temperature during the deposition process in a way even more relevant than even the chosen deposition method. Thus, bismuth oxide thin films with energy bandgaps ranging from the infrared up to near-ultraviolet can be obtained, depending on their structure and morphology. High refractive index of the films can be also attained for specific spectral ranges. When deposited on certain conductive substrates, the films have much lower electrical resistance and even became sensitive to water vapor. Therefore, humidity sensing and optoelectronic applications of the analyzed bismuth oxide thin films can be easily found and used in both science and technology

Higher-Order Kinematics in Dual Lie Algebra

In this chapter, using the ring properties of dual number algebra, vector and tensor calculus, a computing method for the higher-order acceleration vector field properties in general rigid body motion is proposed. The higher-order acceleration field of a rigid body in a general motion is uniquely determined by higher-order time derivative of a dual twist. For the relative kinematics of rigid body motion, equations that allow the determination of the higher-order acceleration vector field are given, using an exponential Brockett-like formula in the dual Lie algebra. In particular cases, the properties for velocity, acceleration, jerk, and jounce fields are given. This approach uses the isomorphism between the Lie algebra of the rigid displacements se(3), of the Special Euclidean group, SE3,and the Lie algebra of dual vectors. The results are coordinate free and in a closed form

Boosting Deep Neural Networks with Geometrical Prior Knowledge: A Survey

While Deep Neural Networks (DNNs) achieve state-of-the-art results in many different problem settings, they are affected by some crucial weaknesses. On the one hand, DNNs depend on exploiting a vast amount of training data, whose labeling process is time-consuming and expensive. On the other hand, DNNs are often treated as black box systems, which complicates their evaluation and validation. Both problems can be mitigated by incorporating prior knowledge into the DNN. One promising field, inspired by the success of convolutional neural networks (CNNs) in computer vision tasks, is to incorporate knowledge about symmetric geometrical transformations of the problem to solve. This promises an increased data-efficiency and filter responses that are interpretable more easily. In this survey, we try to give a concise overview about different approaches to incorporate geometrical prior knowledge into DNNs. Additionally, we try to connect those methods to the field of 3D object detection for autonomous driving, where we expect promising results applying those methods.Comment: Survey Pape

The Complexity of Rational Synthesis

We study the computational complexity of the cooperative and non-cooperative rational synthesis problems, as introduced by Kupferman, Vardi and co-authors. We provide tight results for most of the classical omega-regular objectives, and show how to solve those problems optimally

CLOUD COVER AND INTERPLANETARY MAGNETIC FIELD: POSSIBLE RELATIONSHIP

Solar energy is the main driver of the climate on Eart, thus the variation of solar activity may affect climate variability via changes in irradiation, energetic particles, cosmic ray flux or solar wind parameters. Solar wind is characterized by speed, magnetic and electric fields, flow pressure, particle flux, dynamic pressure, with various effects on atmospheric processes. One of these is the formation and evolution of clouds which play a crucial role in the terrestrial climate, since they induce cooling or warming effects, depending on their heights and composition. Possible relationship between solar activity and cloud cover variability are lately the subject of various studies, but no clear conclusion exists due to contradictory results obtained so far. This article studies the possible relationship between mean cloud cover and the interplanetary magnetic field at global scale, as well as geographical/regional characteristics for the 1984 – 2009 period, i. e. for solar cycles 22-23, when satellite observations are available at global scale and on a continuous basis. The study also shows the seasonal dependence and is made for different cloud height and composition, i. e. for low/middle/high and liquid/ice types of clouds