Parameterization and modelling of large off-road tyres for ride analyses : Part 1 : Obtaining parameterization data

Multi-body vehicle dynamic simulations play a significant role in the design and development process of off-road vehicles. These simulations require tyre models to describe the forces and moments, which are generated in the tyre-road contact patch. All external forces acting on the vehicle are either generated in the tyre–road interface or are due to aerodynamic effects, which can be neglected at typical off-road driving speeds. The accuracy of the tyre model describing the forces in the tyre–road interface is thus of exceptional importance. The parameterization of most tyre models relies on some experimental test data that is used to extract the necessary information to fit model parameters. Acquiring the test data, with sufficient accuracy, is often the biggest challenge in the parameterization process. Published data for large off-road tyres is virtually non-existent. This paper describes different methods to acquire the required parameterization data. Experimental measurements are conducted on a 16.00R20 Michelin XZL tyre. Laboratory tests, as well as field tests, over discrete obstacles and uneven hard surfaces were conducted. The paper presents an extensive set of parameterization and validation test data on a large off-road tyre that can be used by researchers to develop and validate tyre models.http://www.elsevier.com/locate/jterrahb201

Three-Dimensional Phylogeny Explorer: Distinguishing paralogs, lateral transfer, and violation of "molecular clock" assumption with 3D visualization

<p>Abstract</p> <p>Background</p> <p>Construction and interpretation of phylogenetic trees has been a major research topic for understanding the evolution of genes. Increases in sequence data and complexity are creating a need for more powerful and insightful tree visualization tools.</p> <p>Results</p> <p>We have developed 3D Phylogeny Explorer (3DPE), a novel phylogeny tree viewer that maps trees onto three spatial axes (species on the X-axis; paralogs on Z; evolutionary distance on Y), enabling one to distinguish at a glance evolutionary features such as speciation; gene duplication and paralog evolution; lateral gene transfer; and violation of the "molecular clock" assumption. Users can input any tree on the online 3DPE, then rotate, scroll, rescale, and explore it interactively as "live" 3D views. All objects in 3DPE are clickable to display subtrees, connectivity path highlighting, sequence alignments, and gene summary views, and etc. To illustrate the value of this visualization approach for microbial genomes, we also generated 3D phylogeny analyses for all clusters from the public COG database. We constructed tree views using well-established methods and graph algorithms. We used Scientific Python to generate VRML2 3D views viewable in any web browser.</p> <p>Conclusion</p> <p>3DPE provides a novel phylogenetic tree projection method into 3D space and its web-based implementation with live 3D features for reconstruction of phylogenetic trees of COG database.</p

System Calibration for Direct Georeferencing

Within the last years extensive tests were done to investigate the accuracy performance of integrated GPS/inertial systems for direct georeferencing in airborne photogrammetric environments. Based on commercially available high performance GPS/inertial systems direct georeferencing was shown to be a serious alternative to standard indirect image orientation using classical or GPS-supported aerial triangulation. Nonetheless, correct overall system calibration including the GPS/inertial component as well as the imaging sensor itself is the limiting factor in this approach. Since direct georeferencing without ground control relies on an extrapolation process only, remaining errors in the system calibration will significantly decrease the quality of object point determination. Therefore, special focus has to be laid on the overall system calibration procedure. Within this context the stability of system calibration over longer time periods and the influence of additional self-calibration on the calibration parameter estimation are of special interest. The investigations presented in this paper are based on test material from a real flight test, where as one part of a big project a calibration field was flown several times within a two month period using the same GPS/inertial-camera system installation. From this test data first statements on the long term stability of system calibration are feasible, which are important especially from a practical point of view when applying direct georeferencing in photogrammetric production processes. KURZFASSUNG In den letzten Jahren wurden ausgiebige Tests zur Ermittlung des Genauigkeitspotenzials der direkten Georeferenzierung mi

On a Framework for Federated Cluster Analysis

Federated learning is becoming increasingly popular to enable automated learning in distributed networks of autonomous partners without sharing raw data. Many works focus on supervised learning, while the area of federated unsupervised learning, similar to federated clustering, is still less explored. In this paper, we introduce a federated clustering framework that solves three challenges: determine the number of global clusters in a federated dataset, obtain a partition of the data via a federated fuzzy c-means algorithm, and validate the clustering through a federated fuzzy Davies-Bouldin index. The complete framework is evaluated through numerical experiments on artificial and real-world datasets. The observed results are promising, as in most cases the federated clustering framework's results are consistent with its nonfederated equivalent. Moreover, we embed an alternative federated fuzzy c-means formulation into our framework and observe that our formulation is more reliable in case the data are noni.i.d., while the performance is on par in the i.i.d. case

Running head: On Embedding Binary Trees into Hypercubes Proofs should be sent to:

Please direct all correspondence to Prof. Stallmann at the above address

A ONE-WAY ARRAY ALGORITHM FOR MATROID SCHEDULING

The greedy algorithm is a standard paradigm for solving matroid optimization problems on sequential computers. This paper presents a greedy algorithm suitable for a fully-pipelined linear array of processors, a generalization of Huang&apos;s algorithm [Hua90] for minimum spanning trees. Application of the algorithm to uniprocessor scheduling with release times and deadlines is discussed in detail. A key feature of the algorithm is its use of matroid contraction

UNIFORM PLANAR EMBEDDING IS NP-COMPLETE

An instance of the uniform planar embedding (UPE) problem is described by giving a (planar) graph G = (V, E) and a set of uniformity constraints of the form (v: el...ed,w: fl... fd), where {el,...,ed} is the set of edges incident on vertex v and {fl,..., fd} the set incident on w-f- v (v and w must have the same degree). A positive instance is one in which G has a planar embedding that satisfies all uniformity constraints, that is, for each constraint the cyclic permutation of el... ed around v is the same as that of fl...A around w. Uniformity constraints arise in VLSI design applications, where, in a hierarchical design, modules of the same type are required to observe the same pin order. The usual method for enforcing this constraint is to fix the pin order for all modules before doing the layout. The resulting single-layer routing problem can be solved easily in linear time [5], but puts unnecessary restrictions on the layout. UPE is a more general formulation of single-layer routing, which does not impose pin order in advance. Single layer routing problems are important for two reasons: a) one layer, typically metal, may have superior electrical characteristics, making it desirable to place all importan