Urban modeling from LiDAR point clouds is an important topic in computer vision, computer graphics, photogrammetry and remote sensing. 3D city models have found a wide range of applications in smart cities, autonomous navigation, urban planning and mapping etc. However, existing datasets for 3D modeling mainly focus on common objects such as furniture or cars. Lack of building datasets has become a major obstacle for applying deep learning technology to specific domains such as urban modeling. In this paper, we present a urban-scale dataset consisting of more than 160 thousands buildings along with corresponding point clouds, mesh and wire-frame models, covering 16 cities in Estonia about 998 Km2. We extensively evaluate performance of state-of-the-art algorithms including handcrafted and deep feature based methods. Experimental results indicate that Building3D has challenges of high intra-class variance, data imbalance and large-scale noises. The Building3D is the first and largest urban-scale building modeling benchmark, allowing a comparison of supervised and self-supervised learning methods. We believe that our Building3D will facilitate future research on urban modeling, aerial path planning, mesh simplification, and semantic/part segmentation etc.
Daniel Patterson, Noble Mushtak, Andrew Wagner
et al.
Programs are rarely implemented in a single language, and thus questions of type soundness should address not only the semantics of a single language, but how it interacts with others. Even between type-safe languages, disparate features frustrate interoperability, as invariants from one language can easily be violated in the other. In their seminal 2007 paper, Matthews and Findler proposed a multi-language construction that augments the interoperating languages with a pair of boundaries that allow code from one language to be embedded in the other. While the technique has been widely applied, their syntactic source-level interoperability doesn't reflect practical implementations, where behavior of interaction is defined after compilation to a common target, and any safety must be ensured by target invariants or inserted target-level "glue code." In this paper, we present a framework for the design and verification of sound language interoperability that follows an interoperation-after-compilation strategy. Language designers specify what data can be converted between types of the languages via a relation $τ_A \sim τ_B$ and specify target glue code implementing conversions. Then, by giving a semantic model of source types as sets of target terms, we can establish soundness of conversions: i.e., whenever $τ_A \sim τ_B$, the corresponding pair of conversions convert target terms that behave as $τ_A$ to target terms that behave as $τ_B$, and vice versa. We can then prove semantic type soundness for the entire system. We illustrate our framework via a series of case studies that demonstrate how our semantic interoperation-after-compilation approach allows us both to account for complex differences in language semantics and make efficiency trade-offs based on particularities of compilers or targets.
We experimentally generate cylindrically polarized wavepackets with transverse orbital angular momentum, demonstrating the coexistence of spatiotemporal optical vortex with spatial polarization singularity. The results in this paper extend the study of spatiotemporal wavepackets to a broader scope, paving the way for its applications in various areas such as light-matter interaction, optical tweezers, spatiotemporal spin-orbit angular momentum coupling, etc.
The development of functions of real variables in Taylor and Frobenius series (whole series which are formed in nonorthogonal, nonperiodic bases), in sinusoidal Fourier series (bases of orthogonal, periodic functions), in series of special functions (bases of orthogonal, nonperiodic functions), etc. is a commonly used method for solving a wide range of ordinary differential equations (ODEs) and partial differential equations (PDEs).In this article, based on an in-depth analysis of the properties of periodic sinusoidal Fourier series (SFS), we will be able to apply this procedure to a much broader category of ODEs (all linear, homogeneous and non-homogeneous equations with constant coefficients, a large category of linear and non-linear equations with variable coefficients, systems of ODEs, integro-differential equations, etc.). We will also extend this procedure and we use it to solve certain ODEs, on non-orthogonal periodic bases, represented by non sinusoidal periodic Fourier series (SFN).
Linglong Dai, Ruicheng Jiao, Fumiyuki Adachi
et al.
Wireless communications are envisioned to bring about dramatic changes in the future, with a variety of emerging applications, such as virtual reality (VR), Internet of things (IoT), etc., becoming a reality. However, these compelling applications have imposed many new challenges, including unknown channel models, low-latency requirement in large-scale super-dense networks, etc. The amazing success of deep learning (DL) in various fields, particularly in computer science, has recently stimulated increasing interest in applying it to address those challenges. Hence, in this review, a pair of dominant methodologies of using DL for wireless communications are investigated. The first one is DL-based architecture design, which breaks the classical model-based block design rule of wireless communications in the past decades. The second one is DL-based algorithm design, which will be illustrated by several examples in a series of typical techniques conceived for 5G and beyond. Their principles, key features, and performance gains will be discussed. Furthermore, open problems and future research opportunities will also be pointed out, highlighting the interplay between DL and wireless communications. We expect that this review can stimulate more novel ideas and exciting contributions for intelligent wireless communications.
A block scrambling-based encryption scheme is presented to enhance the security of Encryption-then-Compression (EtC) systems with JPEG compression, which allow us to securely transmit images through an untrusted channel provider, such as social network service providers. The proposed scheme enables the use of a smaller block size and a larger number of blocks than the conventional scheme. Images encrypted using the proposed scheme include less color information due to the use of grayscale images even when the original image has three color channels. These features enhance security against various attacks such as jigsaw puzzle solver and brute-force attacks. In an experiment, the security against jigsaw puzzle solver attacks is evaluated. Encrypted images were uploaded to and then downloaded from Facebook and Twitter, and the results demonstrated that the proposed scheme is effective for EtC systems.
In this paper it is developed a simple, analytical and very efficient method capable to provide control of optical beam's intensity over an arbitrary curvilinear (planar) trajectory. The same method also provides the possibility of managing multifurcations of the optical beam. The results presented here can have valuable applications in fields like optical tweezers, optical lithography, atom optical guiding, structured light, etc..
The LLVM compiler framework supports a selection of loop transformations such as vectorization, distribution and unrolling. Each transformation is carried-out by specialized passes that have been developed independently. In this paper we propose an integrated approach to loop optimizations: A single dedicated pass that mutates a Loop Structure DAG. Each transformation can make use of a common infrastructure such as dependency analysis, transformation preconditions, etc.
Could elementary complex analysis, which covers the topics such as algebra of complex numbers, elementary complex functions, complex differentiation and integration, series expansions of complex functions, residues and singularities, and introduction to conformal mappings, be made more elementary? In this paper we demonstrate that a little reorientation of existing elementary complex analysis brings a lot of benefits, including operating with single-valued logarithmic and power functions, making the Cauchy integral formula as a part of fundamental theorem of calculus, removal of residues and singularities, etc. Implicitly, this reorientation consists of resolving the multivalued nature of complex logarithm by considering its Riemann surface. But instead of the advanced mathematical concepts such as manifolds, differential forms, integration on manifolds, etc, which are necessary for introducing complex analysis in Riemann surfaces, we use rather elementary methods of multiplicative calculus. We think that such a reoriented elementary complex analysis could be especially successful as a first course in complex analysis for the students of engineering, physics, even applied mathematics programs who indeed do not see a second and more advanced course in complex analysis. It would be beneficial for the students of pure mathematics programs as well because it is more appropriate introduction to complex analysis on Riemann surfaces rather than the existing one.
The Barcelona-Catania-Paris-Madrid (BCPM) functional recently proposed to describe nuclear structure properties of finite nuclei is generalized as to include a realistic effective mass. The resulting functional is as good as the previous one in describing binding energies, radii, deformation properties, etc and, in addition, the description of Giant Quadrupole Resonance energies is greatly improved.
Cloud computing is the new buzzword in the head of the techies round the clock these days. The importance and the different applications of cloud computing are overwhelming and thus, it is a topic of huge significance. It provides several astounding features like Multitenancy, on demand service, pay per use etc. This manuscript presents an exhaustive survey on cloud computing technology and potential research issues in cloud computing that needs to be addressed.
In order to study quantum measurement theory, sequential product defined for any two quantum effects is introduced. Physically motivated conditions ask the sequential product to be continuous with respect to the strong operator topology. In this paper, we study the continuity problems of the sequential product with respect to the other important topologies, as norm topology, weak operator topology, order topology, interval topology, etc.
In this paper we mainly study the dynamical complexity of Birkhoff ergodic average under the simultaneous observation of any number of continuous functions. These results can be as generalizations of [6,35] etc. to study Birkhorff ergodic average from one (or finite) observable function to any number of observable functions from the dimensional perspective. For any topological dynamical system with $g-$almost product property and uniform separation property, we show that any {\it jointly-irregular set}(i.e., the intersection of a series of $φ-$irregular sets over several continuous functions) either is empty or carries full topological pressure. In particular, if further the system is not uniquely ergodic, then the {\it completely-irregular set}(i.e., intersection of all possible {\it nonempty $φ-$irregular} sets) is nonempty(even forms a dense $G_δ$ set) and carries full topological pressure. Moreover, {\it irregular-mix-regular sets} (i.e., intersection of some $ φ-$irregular sets and $ \varphi-$regular sets) are discussed. Similarly, the above results are suitable for the case of BS-dimension. As consequences, these results are suitable for any system such as shifts of finite type or uniformly hyperbolic diffeomorphisms, time-1 map of uniformly hyperbolic flows, repellers, $β-$shifts etc..
This paper introduces the new interactive Java sketching software KamiWaAi, recently developed at the University of Fukui. Its graphical user interface enables the user without any knowledge of both mathematics or computer science, to do full three dimensional "drawings" on the screen. The resulting constructions can be reshaped interactively by dragging its points over the screen. The programming approach is new. KamiWaAi implements geometric objects like points, lines, circles, spheres, etc. directly as software objects (Java classes) of the same name. These software objects are geometric entities mathematically defined and manipulated in a conformal geometric algebra, combining the five dimensions of origin, three space and infinity. Simple geometric products in this algebra represent geometric unions, intersections, arbitrary rotations and translations, projections, distance, etc. To ease the coordinate free and matrix free implementation of this fundamental geometric product, a new algebraic three level approach is presented. Finally details about the Java classes of the new GeometricAlgebra software package and their associated methods are given. KamiWaAi is available for free internet download. Key Words: Geometric Algebra, Conformal Geometric Algebra, Geometric Calculus Software, GeometricAlgebra, Java Package, Interactive 3D Software, Geometric Objects
This paper gives a personal global point of view on two sciences: electronics and photonics towards plasmonics and solar energy conversion. The new research directions in these two sciences are pointed out by comparison and in the perspective of future new solar devices. A parallel and the equivalence between electronics and photonics are presented. Starting from electron in electronics, photon, solitons and plasmons in photonics, electrical cables - optical fibers, plasmonic wave guides, electrical circuits - optical circuits, electrical transistors - optical transistors, plasmonster, electrical generators - pulsed lasers and spasers, photonics gets step by step all the tools already existing in electronics. Solar energy could be converted in many ways, the most known is the conversion in electricity. Today we need that the energy is in form of electricity because most of the apparatus that we use are based on electricity: informatics, motors, etc. However, the progress in photonics with optical circuits, optical transistors etc., shows that the photonics informatics could be possible. Also the optical manipulation and optical engines concept were already demonstrated experimentally. If the laser propulsion will be achieved, and the optical engines will work, the question that will rise tomorrow is: "Shall we still use the electricity in the future? What will be the solar devices tomorrow?"
The Laplacian matrix of a simple graph is the difference of the diagonal matrix of vertex degree and the (0,1) adjacency matrix. In the past decades, the Laplacian spectrum has received much more and more attention, since it has been applied to several fields, such as randomized algorithms, combinatorial optimization problems and machine learning. This paper is primarily a survey of various aspects of the eigenvalues of the Laplacian matrix of a graph for the past teens. In addition, some new unpublished results and questions are concluded. Emphasis is given on classifications of the upper and lower bounds for the Laplacian eigenvalues of graphs (including some special graphs, such as trees, bipartite graphs, triangular-free graphs, cubic graphs, etc.) as a function of other graph invariants, such as degree sequence, the average 2-degree, diameter, the maximal independence number, the maximal matching number, vertex connectivity, the domination number, the number of the spanning trees, etc.
In this work I present location to first mentioning to result of Robert Geroch Preprint deals with conserving quantities of metric gravitational theories They are constructed from Killing vector fields (if any exists) and symmetric tensors of arbitrary rank with vanishing divergence I also suggest alternative approach by introducing spinorial fields allowing to construct conserved integrals of energy-momentum etc
In this paper, we relate the seemingly unrelated concepts of treewidth and boxicity. Our main result is that, for any graph G, boxicity(G) <= treewidth(G) + 2. We also show that this upper bound is (almost) tight. Our result leads to various interesting consequences, like bounding the boxicity of many well known graph classes, such as chordal graphs, circular arc graphs, AT-free graphs, co--comparability graphs etc. All our bounds are shown to be tight up to small constant factors. An algorithmic consequence of our result is a linear time algorithm to construct a box representation for graphs of bounded treewidth in a space of constant dimension. We also show many structural results as a consequence. In particular, we show that, if the boxicity of a graph is b >= 3, then there exists a simple cycle of length at least b-3 as well as an induced cycle of length at least floor of (log(b-2) to the base Delta) + 2, where Delta is its maximum degree. We also relate boxicity with the cardinality of minimum vertex cover, minimum feedback vertex cover etc. Another structural consequence is that, for any fixed planar graph H, there is a constant c(H) such that, if boxicity(G) >= c(H) then H is a minor of G.