Upward Three-Dimensional Grid Drawings of Graphs

A \emph{three-dimensional grid drawing} of a graph is a placement of the vertices at distinct points with integer coordinates, such that the straight line segments representing the edges do not cross. Our aim is to produce three-dimensional grid drawings with small bounding box volume. We prove that every $n$-vertex graph with bounded degeneracy has a three-dimensional grid drawing with $O(n^{3/2})$ volume. This is the broadest class of graphs admiting such drawings. A three-dimensional grid drawing of a directed graph is \emph{upward} if every arc points up in the z-direction. We prove that every directed acyclic graph has an upward three-dimensional grid drawing with $(n^3)$ volume, which is tight for the complete dag. The previous best upper bound was $O(n^4)$. Our main result is that every $c$-colourable directed acyclic graph ($c$ constant) has an upward three-dimensional grid drawing with $O(n^2)$ volume. This result matches the bound in the undirected case, and improves the best known bound from $O(n^3)$ for many classes of directed acyclic graphs, including planar, series parallel, and outerplanar

Convexity-Increasing Morphs of Planar Graphs

We study the problem of convexifying drawings of planar graphs. Given any planar straight-line drawing of an internally 3-connected graph, we show how to morph the drawing to one with strictly convex faces while maintaining planarity at all times. Our morph is convexity-increasing, meaning that once an angle is convex, it remains convex. We give an efficient algorithm that constructs such a morph as a composition of a linear number of steps where each step either moves vertices along horizontal lines or moves vertices along vertical lines. Moreover, we show that a linear number of steps is worst-case optimal. To obtain our result, we use a well-known technique by Hong and Nagamochi for finding redrawings with convex faces while preserving y-coordinates. Using a variant of Tutte's graph drawing algorithm, we obtain a new proof of Hong and Nagamochi's result which comes with a better running time. This is of independent interest, as Hong and Nagamochi's technique serves as a building block in existing morphing algorithms.Comment: Preliminary version in Proc. WG 201

VIRTUE : integrating CFD ship design

Novel ship concepts, increasing size and speed, and strong competition in the global maritime market require that a ship's hydrodynamic performance be studied at the highest level of sophistication. All hydrodynamic aspects need to be considered so as to optimize trade-offs between resistance, propulsion (and cavitation), seakeeping or manoeuvring. VIRTUE takes a holistic approach to hydrodynamic design and focuses on integrating advanced CFD tools in a software platform that can control and launch multi-objective hydrodynamic design projects. In this paper current practice, future requirements and a potential software integration platform are presented. The necessity of parametric modelling as a means of effectively generating and efficiently varying geometry, and the added-value of advanced visualization, is discussed. An illustrating example is given as a test case, a container carrier investigation, and the requirements and a proposed architecture for the platform are outlined

Artificial reefs

Treball desenvolupat en el marc del programa "European Project Semester".This report is a final report of an EPS project about artificial reefs. The project is being carried out by four engineering students who are studying at Universitat Politécnica de Catalunya in Vilanova I La Geltrù. The aim of the project, which began on February 8th, is to design an artificial reef to restore the flora and fauna in a specific area near a marine observatory established by the company SARTI. The report outlines the methodology used to carry out the project during these months of work, which involved research on the existing fauna in the targeted area (fish and crustacean species), creation and analysis of 3D designs, simulation of the different models and other processes in order to create the most suitable design. The report also contains market and competitive research as well as the analysis of different materials. Overall, the report provides a detailed overview of the two models of artificial reefs that have been created to restore the marine environment.Incomin

The simultaneity of complementary conditions:re-integrating and balancing analogue and digital matter(s) in basic architectural education

The actual, globally established, general digital procedures in basic architectural education,producing well-behaved, seemingly attractive up-to-date projects, spaces and first general-researchon all scale levels, apparently present a certain growing amount of deficiencies. These limitations surface only gradually, as the state of things on overall extents is generally deemed satisfactory. Some skills, such as “old-fashioned” analogue drawing are gradually eased-out ofundergraduate curricula and overall modus-operandi, due to their apparent slow inefficiencies in regard to various digital media’s rapid readiness, malleability and unproblematic, quotidian availabilities. While this state of things is understandable, it nevertheless presents a definite challenge. The challenge of questioning how the assessment of conditions and especially their representation,is conducted, prior to contextual architectural action(s) of any kind

Challenges of model-based definition for high-value manufacturing

Manufacturing Industry is moving towards adoption of 3D models as the ultimate authoritative source for complete product definition replacing 2D drawings, which is called “Model-Based Definition”. Starting its journey from geometric information on design, manufacturing, and inspection, the targets are to achieve the ultimate goal of lifecycle model based enterprise, requiring MBD to be more comprehensive and challenging structure of information instead of just a geometric model. The industry has not yet fully achieved implementation of MBD to whole product lifecycle. This journey is long and tough, and we are still at an early stage, but it will be a decisive factor in gaining competitive advantage by the early adopters, especially in high-value manufacturing. Complete adoption of MBD has several issues and challenges that need to be addressed. This paper presents a review of current literature, intending to cover present state of knowledge, issues, challenges, and future research directions, in the development and adoption of MBD

Structural Design of Pressure Pipeline Wedge-Shaped Concrete Piers

This paper proposed a wedge concrete fixed pier device based on self-locking to solve the problems existing in the fixed pier of water supply pipeline in utility tunnels. The system converted the horizontal thrust, originally applied to the weld seam in the pipeline, into oblique downward pressure by bending the pipeline upward. When the pipeline was bent upward at an angle equal to twice the horizontal angle of the wedge concrete fixed pier, then the fixed pier achieved the variable pressure-bearing effect in the horizontal direction through the self-locking between the concrete pier and the bottom plate of the utility tunnels. In addition, this avoided the damage to the fixed pier device, caused by the instantaneous pipeline internal pressure exceeding the maximum bearing thrust of the weld seam. The wedge fixed pier could be poured twice when the pipeline entered the utility tunnels, saving the rework cost of pouring the concrete again due to the changes of the design positioning of the water supply pipeline. As long as the area of the built-in steel fittings in the wedge concrete exceeded a certain range, the wedge concrete pier would not be crushed