Large bichromatic point sets admit empty monochromatic 4-gons

We consider a variation of a problem stated by Erd˝os and Szekeres in 1935 about the existence of a number fES(k) such that any set S of at least fES(k) points in general position in the plane has a subset of k points that are the vertices of a convex k-gon. In our setting the points of S are colored, and we say that a (not necessarily convex) spanned polygon is monochromatic if all its vertices have the same color. Moreover, a polygon is called empty if it does not contain any points of S in its interior. We show that any bichromatic set of n ≥ 5044 points in R2 in general position determines at least one empty, monochromatic quadrilateral (and thus linearly many).Postprint (published version

Application of Geographic Information Systems

The importance of Geographic Information Systems (GIS) can hardly be overemphasized in today’s academic and professional arena. More professionals and academics have been using GIS than ever – urban & regional planners, civil engineers, geographers, spatial economists, sociologists, environmental scientists, criminal justice professionals, political scientists, and alike. As such, it is extremely important to understand the theories and applications of GIS in our teaching, professional work, and research. “The Application of Geographic Information Systems” presents research findings that explain GIS’s applications in different subfields of social sciences. With several case studies conducted in different parts of the world, the book blends together the theories of GIS and their practical implementations in different conditions. It deals with GIS’s application in the broad spectrum of geospatial analysis and modeling, water resources analysis, land use analysis, infrastructure network analysis like transportation and water distribution network, and such. The book is expected to be a useful source of knowledge to the users of GIS who envision its applications in their teaching and research. This easy-to-understand book is surely not the end in itself but a little contribution to toward our understanding of the rich and wonderful subject of GIS

Collection of abstracts of the 24th European Workshop on Computational Geometry

International audienceThe 24th European Workshop on Computational Geomety (EuroCG'08) was held at INRIA Nancy - Grand Est & LORIA on March 18-20, 2008. The present collection of abstracts contains the 63 scientific contributions as well as three invited talks presented at the workshop

Proceedings of the NASA Conference on Space Telerobotics, volume 1

The theme of the Conference was man-machine collaboration in space. Topics addressed include: redundant manipulators; man-machine systems; telerobot architecture; remote sensing and planning; navigation; neural networks; fundamental AI research; and reasoning under uncertainty

LIPIcs, Volume 274, ESA 2023, Complete Volume

LIPIcs, Volume 274, ESA 2023, Complete Volum

Advanced Techniques for Design and Manufacturing in Marine Engineering

Modern engineering design processes are driven by the extensive use of numerical simulations; naval architecture and ocean engineering are no exception. Computational power has been improved over the last few decades; therefore, the integration of different tools such as CAD, FEM, CFD, and CAM has enabled complex modeling and manufacturing problems to be solved in a more feasible way. Classical naval design methodology can take advantage of this integration, giving rise to more robust designs in terms of shape, structural and hydrodynamic performances, and the manufacturing process.This Special Issue invites researchers and engineers from both academia and the industry to publish the latest progress in design and manufacturing techniques in marine engineering and to debate the current issues and future perspectives in this research area. Suitable topics for this issue include, but are not limited to, the following:CAD-based approaches for designing the hull and appendages of sailing and engine-powered boats and comparisons with traditional techniques;Finite element method applications to predict the structural performance of the whole boat or of a portion of it, with particular attention to the modeling of the material used;Embedded measurement systems for structural health monitoring;Determination of hydrodynamic efficiency using experimental, numerical, or semi-empiric methods for displacement and planning hulls;Topology optimization techniques to overcome traditional scantling criteria based on international standards;Applications of additive manufacturing to derive innovative shapes for internal reinforcements or sandwich hull structures

Using MapReduce Streaming for Distributed Life Simulation on the Cloud

Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

Scale-Bridging of Elasto-Plastic Microstructures using Statistically Similar Representative Volume Elements

Die vorliegende Arbeit behandelt die numerische Modellierung des mechanischen Verhaltens mikroheterogener Materialien, wobei das Hauptaugenmerk auf Dualphasenstähle gelegt wird. Ihr makroskopisches Verhalten wird durch die Interaktion der Einzelphasen auf mikrostruktureller Ebene geprägt. Der Einfluss der Morphologie einer realistischen Mikrostruktur kann durch die Verwendung von repräsentativen Volumenelementen (RVEs) unter Anwendung der FE²-Methode direkt in die Materialmodellierung einbezogen werden. Dabei entsteht für RVEs, die als Ausschnitte einer realen Mikrostruktur konstruiert werden, ein enormer Rechenaufwand. Eine Reduzierung des Aufwands ist durch die Verwendung von statistisch ähnlichen RVEs (SSRVEs) möglich. Diese sind durch Ähnlichkeit in Bezug auf bestimmte statistische Maße definiert und liefern gleichzeitig Gleichartigkeit des mechanischen Verhaltens. Die verschiedenen Aspekte der Konstruktion von SSRVEs sind ein Schwerpunkt dieser Arbeit. Es wird gezeigt, dass SSRVEs die mechanischen Eigenschaften der realen Mikrostruktur widerspiegeln und damit ihre Verwendung im Rahmen der FE² -Methode ermöglicht wird. Die Simulation makroskopischer Eigenschaften basierend auf polykristallinen RVEs wird gezeigt. Diese ermöglichen die Beschreibung polykristalliner Materialien, welche von ihrer mikrostrukturellen Textur geprägt werden.The present work deals with the numerical modeling of the mechanical behavior of microheterogeneous materials, with a focus on dual-phase steel. The macroscopic behavior of this material is largely influenced by an interaction of the microstructural constituents. The influence of the morphology of a real microstructure can be included in the material modeling by the application of a suitable representative volume element (RVE) in a direct micro-macro homogenization scheme (also known as FE²-method). However, the use of sections of a real microstructure as an RVE can lead to huge computational costs. A cost reduction can be achieved by the application of statistically similar RVEs (SSRVEs). They are governed by similarities of selected statistical measures with respect to a real microstructure and show a comparable mechanical behavior. The different aspects in the construction method are a main focus of this work. It is shown that SSRVEs can resemble the mechanical behavior of a real DP steel microstructure appropriately, which permits their use in FE²-simulations instead of real microstructures. Aiming for a description of polycrystalline materials governed by texture, the simulation of macroscopic properties based on polycrystalline RVEs is shown