1,396 research outputs found

    Co-projection-plane based 3-D padding for polyhedron projection for 360-degree video

    Full text link
    The polyhedron projection for 360-degree video is becoming more and more popular since it can lead to much less geometry distortion compared with the equirectangular projection. However, in the polyhedron projection, we can observe very obvious texture discontinuity in the area near the face boundary. Such a texture discontinuity may lead to serious quality degradation when motion compensation crosses the discontinuous face boundary. To solve this problem, in this paper, we first propose to fill the corresponding neighboring faces in the suitable positions as the extension of the current face to keep approximated texture continuity. Then a co-projection-plane based 3-D padding method is proposed to project the reference pixels in the neighboring face to the current face to guarantee exact texture continuity. Under the proposed scheme, the reference pixel is always projected to the same plane with the current pixel when performing motion compensation so that the texture discontinuity problem can be solved. The proposed scheme is implemented in the reference software of High Efficiency Video Coding. Compared with the existing method, the proposed algorithm can significantly improve the rate-distortion performance. The experimental results obviously demonstrate that the texture discontinuity in the face boundary can be well handled by the proposed algorithm.Comment: 6 pages, 9 figure

    Analytical method of designing a comparable milling machine model based on Matlab/Simulink

    Get PDF
    Because of time-varying, nonlinearity and complexity of the machining process, the traditional PID control has been unable to meet the requirements, which are being high-speed and high-precision. However, an advanced control methods can be a good solution for this kind of control system, a prefect simulation results depends on the accuracy of the modeling process, such models can be used to develop more precise and formalized description of process activities, on modeling process, and now a days a lot of software had been used do this issue. This paper aims to create a milling machine process model using the Simulink modeling method, which use the logic of cutting process as a mathematical terms indicates areal milling machining equations, and give it appropriate processing parameters to ensure the simulating results are comparable, the step response method will be used as good indicator to compare the Model process, using Matlab analysis, first the process will be modelled in the Matlab software to test the step response under various parameters and then compare the results

    A 2-Approximation Algorithm for the Complementary Maximal Strip Recovery Problem

    Get PDF
    The Maximal Strip Recovery problem (MSR) and its complementary (CMSR) are well-studied NP-hard problems in computational genomics. The input of these dual problems are two signed permutations. The goal is to delete some gene markers from both permutations, such that, in the remaining permutations, each gene marker has at least one common neighbor. Equivalently, the resulting permutations could be partitioned into common strips of length at least two. Then MSR is to maximize the number of remaining genes, while the objective of CMSR is to delete the minimum number of gene markers. In this paper, we present a new approximation algorithm for the Complementary Maximal Strip Recovery (CMSR) problem. Our approximation factor is 2, improving the currently best 7/3-approximation algorithm. Although the improvement on the factor is not huge, the analysis is greatly simplified by a compensating method, commonly referred to as the non-oblivious local search technique. In such a method a substitution may not always increase the value of the current solution (it sometimes may even decrease the solution value), though it always improves the value of another function seemingly unrelated to the objective function

    Response Time Analysis of Hierarchical Scheduling: the Synchronized Deferrable Servers Approach

    Get PDF
    Hierarchical scheduling allows reservation of processor bandwidth and the use of different schedulers for different applications on a single platform. We propose a hierarchical scheduling interface called synchronized deferrable servers that can reserve different processor bandwidth on each core, and can combine global and partitioned scheduling on a multicore platform. Significant challenges will arise in the response time analysis of a task set if the tasks are globally scheduled on a multiprocessor platform and the processor bandwidth reserved for the tasks on each processor is different; as a result, existing works on response time analysis for dedicated scheduling on identical multiprocessor platforms are no longer applicable. A new response time analysis that overcomes these challenges is presented and evaluated by simulations. Based on this new analysis, we show that evenly allocating bandwidth across cores is “better” than other allocation schemes in terms of schedulability, and that the threshold between lightweight and heavyweight tasks under hierarchical scheduling may be different from the threshold under dedicated scheduling
    • …
    corecore