Background replacement using chromatic adaptation transform for visual communication

Replacing a video chat background with a landscape image can generate the realism of a user actually being in the landscape. To enhance this realism, we proposed in our previous study a background replacement method that uses a chromatic adaptation transform. This method can enhance the realism of video chat by fitting the color of the foreground image to an illuminant color of a landscape, which is used as the new background image. However, if an incorrect color of the landscape illuminant is obtained through this method, which estimates the illuminant color on the basis of a gray world assumption, the method might not enhance the realism. This is because it converts the foreground color to an incorrect color. In this paper, we therefore propose a method to estimate illuminant color on the basis of the dichromatic reflection model, which improves background replacement using the chromatic adaptation transform. We perform a subjective evaluation using 13 subjects to examine the effects of the proposed method. The results indicate that the proposed method can effectively enhance the realism of the background replacement video.     

Nonlinear growth in weighted networks with neighborhood preferential attachment

We propose a nonlinear growing model for weighted networks with two significant characteristics: (i) the new weights triggered by new edges at each time step grow nonlinearly with time; and (ii) a neighborhood local-world exists for local preferential attachment, which is defined as one selected node and its neighbors. Global strength-driven and local weight-driven preferential attachment mechanisms are involved in our model. We study the evolution process through both mathematical analysis and numerical simulation, and find that the model exhibits a wide-range power-law distribution for node degree, strength, and weight. In particular, a nonlinear degree–strength relationship is obtained. This nonlinearity implies that accelerating growth of new weights plays a nontrivial role compared with accelerating growth of edges. Because of the specific local-world model, a small-world property emerges, and a significant hierarchical organization, independent of the parameters, is observed.     

读“等效的磁荷观点”有感

文章在假想的“磁荷世界”中修改了麦克斯韦方程组和洛伦兹力公式.由磁的库仑定律出发,并根据磁荷与电荷产生的电磁场的等效性,得到真空中静磁场的高斯定理和环路定理.仿照“电荷世界”中的电流定义了磁流强度,又根据磁场的相对论变换,由毕奥—萨伐尔定律和法拉第电磁感应定律得到稳恒电场D的高斯定理和环路定理.     

概率XML数据模型的综述

随着XML成为网络信息表示和交换的标准以及不确定数据的广泛存在,概率XML数据库管理技术成为了当今研究的热点,研究者根据概率数据的类型和解决实际问题的需要提出了多种概率XML数据模型。首先介绍了概率XML数据管理技术的概念,特点和挑战;其次综述了概率XML数据和概率XML数据模型,各种模型的核心思想都来自于可能世界模型,通过选择孩子节点以及删除节点可得到一个可能世界的实例,而且所有实例的概率之和为1;最后介绍了不同模型之间的转换关系。为概率XML数据库的查询、规范化理论奠定了基础。     

无线多媒体传感器网络部署控制算法

已有的无线多媒体传感器网络（WMSNs）研究针对传感器放置在目标区域内的情况进行,且没有考虑节点通过云台的转动获得的整个可能感知区域对覆盖率的影响。本文首先针对节点放置点高于目标区域的应用进行研究,综合考虑节点感知区域和可能感知区域,建立了延时和无延时感知模型,并针对不同的感知模型提出了传感器网络部署控制算法（IVPDCA）,算法中改进了虚拟势场算法,定义了节点质量的概念来表示节点间覆盖重叠的大小,建立受力模型,使得节点在合力作用下进行重新部署,同时关闭冗余节点,既延长了网络寿命,又提高了区域覆盖率。仿真结果验证了算法的有效性。     

Theoretical analysis on the energy density of a laser field measured along an inertial world line of the space-time

Some mathematical relationships, in both the time and frequency domains, are presented in relation to the energy density and dipole-moment matrix element associated with a linearly polarized laser field evaluated on an inertial world line of the Minkowski space-time. As final result, we arrive at a formula for the minimum value of the time interval along which the field is evaluated.     

中国革命和世界政治视野下的民主集中制

政体是把一个国家组织起来的根本性制度或手段,在中国,民主集中制不仅是一种事实性政体,体现了党和国家领导制度的关系原则,并贯穿在横向的“行政−立法”“政治−经济”和纵向的“中央−地方” “国家−社会”的四大结构性维度之中。民主集中制同时还是一个政策过程,作为连接现代化的国家治理体系和实现现代化的治理能力的中介机制,展现了中国国家治理的体制吸纳力、制度组织力和政策执行力。     

规范 · 推论 · 交往 · 世界—布兰顿哲学的四个维度

布兰顿首先将“规范”当作人类活动的核心特征,并以实用主义的方式回答了规范的性质问题;然后再由规范引出推论作为语言意义的根据,并澄清了实质推论的基础地位;接着又进一步,细致解析了推论的实际运作机制,将推论落实于社会交往的过程之中,认为社会交往本质上是不同成员之间的道义计分;最后,在推论主义框架下解释了真、表象语汇的必要性,并对语言与世界的关系做出了推论主义的说明。他的哲学体系由规范、推论、交往、世界四个维度组成。它们层层递进,形成了一个具有严密内在结构的有机整体。原本分散甚至对立的论题,在此得到整合。     

世界而非东亚的鲁迅—鲁迅与法兰西文化谈片

鲁迅对文艺复兴以来拉丁语系的意大利和法兰西文明的认识,其系统性和深度明显超过他对东北欧诸弱小民族（主要是斯拉夫语系文学）的译介。鲁迅关注法兰西文明,重点在文艺,也兼顾科学技术、政治历史和思想学术。他关心法国现代科技背后的人文思想,反思“法兰西革命”之后个人与群体的关系,关心当代法国政治（包括法国在北非殖民地的政策）,留意法国文化人的政治立场,从中获得对现代中国知识分子有益的启迪。鲁迅并非法国文学专家,也不通法语,但他毕生关心法国文学,零星的译介积少成多。他对卢梭、雨果、波德莱尔、罗曼·罗兰、法朗士、安德烈·纪德、德哥派拉等法国作家的理解相当深入。他在现代创作版画方面的“拿来”和“送去”,更是中法文艺交流史上辉煌的一页。梳理鲁迅与法兰西文明的关系,有利于突破过去将鲁迅囿于中国或东亚的狭隘视野,更清楚地看出“世界鲁迅”的大气象。