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991.
Amirkhanov A Heinzl C Reiter M Gröller E 《IEEE transactions on visualization and computer graphics》2010,16(6):1477-1486
Industrial cone-beam X-Ray computed tomography (CT) systems often face problems due to artifacts caused by a bad placement of the specimen on the rotary plate. This paper presents a visual-analysis tool for CT systems, which provides a simulation-based preview and estimates artifacts and deviations of a specimen's placement using the corresponding 3D geometrical surface model as input. The presented tool identifies potentially good or bad placements of a specimen and regions of a specimen, which cause the major portion of artefacts. The tool can be used for a preliminary analysis of the specimen before CT scanning, in order to determine the optimal way of placing the object. The analysis includes: penetration lengths, placement stability and an investigation in Radon space. Novel visualization techniques are applied to the simulation data. A stability widget is presented for determining the placement parameters' robustness. The performance and the comparison of results provided by the tool compared with real world data is demonstrated using two specimens. 相似文献
992.
Sezgin Meliha Kern-Isberner Gabriele Beierle Christoph 《Annals of Mathematics and Artificial Intelligence》2021,89(10-11):1101-1131
Annals of Mathematics and Artificial Intelligence - Probability kinematics is a leading paradigm in probabilistic belief change. It is based on the idea that conditional beliefs should be... 相似文献
993.
The dimensional measurement of microsystem components is a field of application that is gaining more and more importance. While optical probing systems offer a number of advantages, their performance is strongly affected by the varying optical properties of the measured surfaces. For this reason, tactile probing systems are essential to many fields of micrometrology. Since conventional tactile probing systems are not suitable for the measurement of microparts, there is a demand for new tactile probing systems that are specifically adapted to the requirements of micrometrology. The tactile–optical Werth Fiber Probe is an established solution within this scope of application. In the present paper, two recent approaches to adding full 3D capabilities to the fiber probe principle are proposed. First prototypes of these sensors are shown and the obtained results are discussed. 相似文献
994.
Herrmann S Kaehler M Souffrant R Rachholz R Zierath J Kluess D Mittelmeier W Woernle C Bader R 《Computer methods and programs in biomedicine》2012,105(2):109-119
Instability of artificial joints is still one of the most prevalent reasons for revision surgery caused by various influencing factors. In order to investigate instability mechanisms such as dislocation under reproducible, physiologically realistic boundary conditions, a novel test approach is introduced by means of a hardware-in-the-loop (HiL) simulation involving a highly flexible mechatronic test system. In this work, the underlying concept and implementation of all required units is presented enabling comparable investigations of different total hip and knee replacements, respectively. The HiL joint simulator consists of two units: a physical setup composed of a six-axes industrial robot and a numerical multibody model running in real-time. Within the multibody model, the anatomical environment of the considered joint is represented such that the soft tissue response is accounted for during an instability event. Hence, the robot loads and moves the real implant components according to the information provided by the multibody model while transferring back the position and resisting moment recorded. Functionality of the simulator is proved by testing the underlying control principles, and verified by reproducing the dislocation process of a standard total hip replacement. HiL simulations provide a new biomechanical testing tool for analyzing different joint replacement systems with respect to their instability behavior under realistic movements and physiological load conditions. 相似文献
995.
Marek Chrobak Christoph Dürr Flavio Guí?ez Antoni Lozano Nguyen Kim Thang 《Algorithmica》2012,64(2):267-278
Discrete tomography deals with reconstructing finite spatial objects from their projections. The objects we study in this paper are called tilings or tile-packings, and they consist of a number of disjoint copies of a fixed tile, where a tile is defined as a connected set of grid points. A row projection specifies how many grid points are covered by tiles in a given row; column projections are defined analogously. For a fixed tile, is it possible to reconstruct its tilings from their projections in polynomial time? It is known that the answer to this question is affirmative if the tile is a bar (its width or height is 1), while for some other types of tiles $\mathbb {NP}$ -hardness results have been shown in the literature. In this paper we present a complete solution to this question by showing that the problem remains $\mathbb {NP}$ -hard for all tiles other than bars. 相似文献
996.
997.
Dipl.-Wi.-Ing. Christoph Flath Dipl.-Wi.-Ing. David Nicolay Dr. Tobias Conte PD Dr. Clemens van Dinther Dr. Lilia Filipova-Neumann 《WIRTSCHAFTSINFORMATIK》2012,54(1):33-42
The introduction of smart meter technology is a great challenge for the German energy industry. It requires not only large investments in the communication and metering infrastructure, but also a redesign of traditional business processes. The newly incurring costs cannot be fully passed on to the end customers. One option to counterbalance these expenses is to exploit the newly generated smart metering data for the creation of new services and improved processes. For instance, performing a cluster analysis of smart metering data focused on the customers?? time-based consumption behavior allows for a detailed customer segmentation. In the article we present a cluster analysis performed on real-world consumption data from a smart meter project conducted by a German regional utilities company. We show how to integrate a cluster analysis approach into a business intelligence environment and evaluate this artifact as defined by design science. We discuss the results of the cluster analysis and highlight options to apply them to segment-specific tariff design. 相似文献
998.
We consider an online scheduling problem, motivated by the issues present at the joints of networks using ATM and TCP/IP. Namely, IP packets have to be broken down into small ATM cells and sent out before their deadlines, but cells corresponding to different packets can be interwoven. More formally, we consider the online scheduling problem with preemptions, where each job j is revealed at release time r j , and has processing time p j , deadline?d j , and weight w j . A?preempted job can be resumed at any time. The goal is to maximize the total weight of all jobs completed on time. Our main results are as follows. Firstly, we prove that when the processing times of all jobs are at most k, the optimum deterministic competitive ratio is ??(k/log?k). Secondly, we give a deterministic algorithm with competitive ratio depending on the ratio between the smallest and the largest processing time of all jobs. In particular, it attains competitive ratio 5 in the case when all jobs have identical processing times, for which we give a lower bound of 2.598. The latter upper bound also yields an O(log?k)-competitive randomized algorithm for the variant with processing times bounded by k. 相似文献
999.
Breitenbach Stefan Unterweger Christoph Lumetzberger Alexander Duchoslav Jiri Stifter David Hassel Achim Walter Fürst Christian 《Journal of Porous Materials》2021,28(3):727-739
Journal of Porous Materials - In this study, the production of porous carbon fibers from viscose fibers was investigated. The effects of final carbonization temperature... 相似文献
1000.
Vivek Jeyakumar Nedaa Amraish Eugenia Niculescu-Morsza Christoph Bauer Dieter Pahr Stefan Nehrer 《International journal of molecular sciences》2021,22(8)
Tissue engineering strategies promote bone regeneration for large bone defects by stimulating the osteogenesis route via intramembranous ossification in engineered grafts, which upon implantation are frequently constrained by insufficient integration and functional anastomosis of vasculature from the host tissue. In this study, we developed a hybrid biomaterial incorporating decellularized cartilage extracellular matrix (CD-ECM) as a template and silk fibroin (SF) as a carrier to assess the bone regeneration capacity of bone marrow-derived mesenchymal stem cells (hBMSC’s) via the endochondral ossification (ECO) route. hBMSC’s were primed two weeks for chondrogenesis, followed by six weeks for hypertrophy onto hybrid CD-ECM/SF or SF alone scaffolds and evaluated for the mineralized matrix formation in vitro. Calcium deposition biochemically determined increased significantly from 4-8 weeks in both SF and CD-ECM/SF constructs, and retention of sGAG’s were observed only in CD-ECM/SF constructs. SEM/EDX revealed calcium and phosphate crystal localization by hBMSC’s under all conditions. Compressive modulus reached a maximum of 40 KPa after eight weeks of hypertrophic induction. μCT scanning at eight weeks indicated a cloud of denser minerals in groups after hypertrophic induction in CD-ECM/SF constructs than SF constructs. Gene expression by RT-qPCR revealed that hBMSC’s expressed hypertrophic markers VEGF, COL10, RUNX2, but the absence of early hypertrophic marker ChM1 and later hypertrophic marker TSBS1 and the presence of osteogenic markers ALPL, IBSP, OSX under all conditions. Our data indicate a new method to prime hBMSC’S into the late hypertrophic stage in vitro in mechanically stable constructs for ECO-mediated bone tissue regeneration. 相似文献