在不改变译码性能的条件下,为了加快最大后验概率(Maximum A Posteriori Probability,MAP)译码器状态信息更新的速度和降低算法的复杂度,提出了一种用于Turbo码的MAP译码器的免归一化处理算法。算法采用二进制补码加法器和减法器将MAP...在不改变译码性能的条件下,为了加快最大后验概率(Maximum A Posteriori Probability,MAP)译码器状态信息更新的速度和降低算法的复杂度,提出了一种用于Turbo码的MAP译码器的免归一化处理算法。算法采用二进制补码加法器和减法器将MAP译码过程中的状态信息投影到一个归一化圆上,当状态信息更新时所有的状态信息在归一化圆上移动,通过保持归一化圆上状态信息的正确关系来计算似然比。归一化过程中不用搜索或估计状态信息的最大值,通过简化状态信息归一化过程加速了MAP译码器的状态信息更新并降低了复杂度。所提算法在与传统算法译码性能相同的情况下,可以降低36.2%的计算复杂度和17.4%的关键路径延迟,达到MAP译码器实现中的高速、低复杂度目标。展开更多
In 1965 Baker first considered the distribution of Julia sets of transcendental entire maps and proved that the Julia set of an entire map cannot be contained in any finite set of straight lines.In this paper we shall...In 1965 Baker first considered the distribution of Julia sets of transcendental entire maps and proved that the Julia set of an entire map cannot be contained in any finite set of straight lines.In this paper we shall consider the distribution problem of Julia sets of meromorphic maps.We shall show that the Julia set of a transcendental meromorphic map with at most finitely many poles cannot be contained in any finite set of straight lines.Meanwhile,examples show that the Julia sets of meromorphic maps with infinitely many poles may indeed be contained in straight lines.Moreover,we shall show that the Julia set of a transcendental analytic self-map of C*can neither contain a free Jordan arc nor be contained in any finite set of straight lines.展开更多
Reaction wheel or reaction thruster is employed to maintain the attitude of the base of space robot fixed in attitude control of free flying space robot. However, in this method, a large amount of fuel will be consume...Reaction wheel or reaction thruster is employed to maintain the attitude of the base of space robot fixed in attitude control of free flying space robot. However, in this method, a large amount of fuel will be consumed, and it will shorten the on orbit life span of space robot, it also vibrate the system and make the system unsteady. The restricted minimum disturbance map (RMDM) based algorithm of attitude control is presented to keep the attitude of the base fixed during the movement of the manipulator. In this method it is realized by planning motion trajectory of the end effector of manipulator without using reaction wheel or reaction thruster. In order to verify the feasibility and effectiveness of the algorithm attitude control presented in this paper, computer simulation experiments have been made and the experimental results demonstrate that this algorithm is feasible.展开更多
Depth maps are used for synthesis virtual view in free-viewpoint television （FTV） systems. When depth maps are derived using existing depth estimation methods, the depth distortions will cause undesirable artifacts ...Depth maps are used for synthesis virtual view in free-viewpoint television （FTV） systems. When depth maps are derived using existing depth estimation methods, the depth distortions will cause undesirable artifacts in the synthesized views. To solve this problem, a 3D video quality model base depth maps （D-3DV） for virtual view synthesis and depth map coding in the FTV applications is proposed. First, the relationships between distortions in coded depth map and rendered view are derived. Then, a precisely 3DV quality model based depth characteristics is develop for the synthesized virtual views. Finally, based on D-3DV model, a multilateral filtering is applied as a pre-processed filter to reduce rendering artifacts. The experimental results evaluated by objective and subjective methods indicate that the proposed D-3DV model can reduce bit-rate of depth coding and achieve better rendering quality.展开更多
自由贸易协定作为国际贸易的重要议题,是加快构建各国新发展格局的重要内容。基于Web of Science核心数据库中的669篇与自由贸易协定相关的英文论文,运用CiteSpace和R语言进行文献计量分析及知识图谱绘制,探究该领域的研究现状和趋势。...自由贸易协定作为国际贸易的重要议题,是加快构建各国新发展格局的重要内容。基于Web of Science核心数据库中的669篇与自由贸易协定相关的英文论文,运用CiteSpace和R语言进行文献计量分析及知识图谱绘制,探究该领域的研究现状和趋势。结果表明:中国和美国相关研究较多,且与其他国家和机构之间的合作较为紧密;相关研究涉及自由贸易协定的定义特点、测度其影响程度的模型工具以及与其他贸易政策工具的对比分析等主题;研究热点的演进从关注如何构建自由贸易协定转向如何更加完善有效地测度自由贸易协定的影响程度。展开更多
文摘在不改变译码性能的条件下,为了加快最大后验概率(Maximum A Posteriori Probability,MAP)译码器状态信息更新的速度和降低算法的复杂度,提出了一种用于Turbo码的MAP译码器的免归一化处理算法。算法采用二进制补码加法器和减法器将MAP译码过程中的状态信息投影到一个归一化圆上,当状态信息更新时所有的状态信息在归一化圆上移动,通过保持归一化圆上状态信息的正确关系来计算似然比。归一化过程中不用搜索或估计状态信息的最大值,通过简化状态信息归一化过程加速了MAP译码器的状态信息更新并降低了复杂度。所提算法在与传统算法译码性能相同的情况下,可以降低36.2%的计算复杂度和17.4%的关键路径延迟,达到MAP译码器实现中的高速、低复杂度目标。
文摘In 1965 Baker first considered the distribution of Julia sets of transcendental entire maps and proved that the Julia set of an entire map cannot be contained in any finite set of straight lines.In this paper we shall consider the distribution problem of Julia sets of meromorphic maps.We shall show that the Julia set of a transcendental meromorphic map with at most finitely many poles cannot be contained in any finite set of straight lines.Meanwhile,examples show that the Julia sets of meromorphic maps with infinitely many poles may indeed be contained in straight lines.Moreover,we shall show that the Julia set of a transcendental analytic self-map of C*can neither contain a free Jordan arc nor be contained in any finite set of straight lines.
文摘Reaction wheel or reaction thruster is employed to maintain the attitude of the base of space robot fixed in attitude control of free flying space robot. However, in this method, a large amount of fuel will be consumed, and it will shorten the on orbit life span of space robot, it also vibrate the system and make the system unsteady. The restricted minimum disturbance map (RMDM) based algorithm of attitude control is presented to keep the attitude of the base fixed during the movement of the manipulator. In this method it is realized by planning motion trajectory of the end effector of manipulator without using reaction wheel or reaction thruster. In order to verify the feasibility and effectiveness of the algorithm attitude control presented in this paper, computer simulation experiments have been made and the experimental results demonstrate that this algorithm is feasible.
基金supported by the National Natural Science Foundation of China(Grant No.60832003)Key Laboratory of Advanced Display and System Application(Shanghai University),Ministry of Education,China(Grant No.P200902)the Key Project of Science and Technology Commission of Shanghai Municipality(Grant No.10510500500)
文摘Depth maps are used for synthesis virtual view in free-viewpoint television （FTV） systems. When depth maps are derived using existing depth estimation methods, the depth distortions will cause undesirable artifacts in the synthesized views. To solve this problem, a 3D video quality model base depth maps （D-3DV） for virtual view synthesis and depth map coding in the FTV applications is proposed. First, the relationships between distortions in coded depth map and rendered view are derived. Then, a precisely 3DV quality model based depth characteristics is develop for the synthesized virtual views. Finally, based on D-3DV model, a multilateral filtering is applied as a pre-processed filter to reduce rendering artifacts. The experimental results evaluated by objective and subjective methods indicate that the proposed D-3DV model can reduce bit-rate of depth coding and achieve better rendering quality.
文摘自由贸易协定作为国际贸易的重要议题,是加快构建各国新发展格局的重要内容。基于Web of Science核心数据库中的669篇与自由贸易协定相关的英文论文,运用CiteSpace和R语言进行文献计量分析及知识图谱绘制,探究该领域的研究现状和趋势。结果表明:中国和美国相关研究较多,且与其他国家和机构之间的合作较为紧密;相关研究涉及自由贸易协定的定义特点、测度其影响程度的模型工具以及与其他贸易政策工具的对比分析等主题;研究热点的演进从关注如何构建自由贸易协定转向如何更加完善有效地测度自由贸易协定的影响程度。
