面向P2P特定信息的传播动力学模型研究

鉴于P2P特定信息传播与传染病传播的相似性,传播动力学是P2P特定信息传播的最新研究方向。针对现有传播动力学模型都不能准确模拟P2P特定信息传播过程的问题,对现有的SEIR传播动力学模型进行改进,建立了SEInR模型。该模型的主要特点包括:将传统的感染者(I)分为n个子类,每个子类赋予不同的模型参数;建立潜伏者(E)与移除者(R)之间的转换关系等。应用现代数学中的矩阵理论,得到SEInR模型的基本再生数计算公式,并对其进行分析。仿真结果表明,所提出的SEInR模型比传统SEIR模型能够更准确地模拟P2P特定信息传播过程,得到的基本再生数计算公式能够准确反映P2P特定信息的传播阂值。     

基于重复任务的复杂结构挖掘

过程挖掘对于部署新的商业流程以及审计、分析和改进已有的流程是非常有帮助的。在商业流程系统日志中,同名任务和重复任务是大量存在的。现有的挖掘算法都不能很好地区分,这导致在过程挖掘的结果中往往会产生不准确的流程模型。为了提高过程挖掘的准确性,提出了一种改进方法,它不仅能够挖掘日志中的循环结构、非自由选择结构等复杂结构,还能够挖掘日志中的同名任务和重复任务。     

ORDBMS中继承层次查询的设计与实现

文章针对新型工程数据库系统－对象－关系数据库的面向对象的特点,研究了复杂对象的继承机制,设计了对继承层次查询的方法,并在工程数据库ANGEL－Ⅱ中实现了该设计。     

基于DSP的HPI与主机通信的实现

本文介绍利用TMS320VC5402中主机接口HPI实现与主机通信,不需要增加太多额外的硬件设备和软件开销,外部主机通过HPI口对DSP系统的RAM进行访问.不会影响DSP的其它处理过程.实现了一种TMS320VC5402 DSP与AT89C51单片机通信的硬件连接方案和软件实现方法,给出了部分程序代码.实验结论证明这种方案可行、有效,对于一些复杂系统的设计具有很好的借鉴意义.     

Color system for skin color extraction

This paper describes a skin color extraction method which has high speed and high accuracy. There were many systems which could achieve the requirements, but they were useless due to tough limitations such as using two cameras to recognize correct coordinates, running only a specific background, wearing several gears, learning the users detailed information in advance, making a personalized database, and so on. In contrast, our approach, which uses the YIQ color system with a background estimation method for skin color extraction, achieved a good performance more than 30 fps, with strong robustness in complicated and poorly illuminated environments. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007     

K(Knowledge)-net: building up and its dynamics

The essence of intelligence is to use certain abilities to obtain knowledge, to use that knowledge, and to operate with that knowledge. New knowledge learned by a human is often related to old existing knowledge, and sometimes we could have more conceptual knowledge based on old knowledge. So, the knowledge in the brain exists in a related structural form, and this structure is dynamic, and therefore is evolvable. Based on the understanding of the real process of learning by a human being, we discuss how to make a model to describe the dynamic structure of knowledge. This model is also a principle of artificial brain design. Most of the knowledge a child learns is from natural language and perception information, and we define this as semantic knowledge. The model to describe the process and structure of knowledge growing in a network form is called a K-net. It is a dynamic network with two main dynamics: one is new knowledge added, and the other is aggregating knowledge existing in the network with some probability. Under these very natural conditions, we found that the network is originally a simple random net, and then some characteristics of a complex network gradually appear when more new knowledge is added and aggregated. A more interesting phenomenon is the appearance of a random hierarchical structure. Does this mean emergence?     

Towards a continuous microfluidic rheometer

In a previous paper we presented a way to measure the rheological properties of complex fluids on a microfluidic chip (Guillot et al., Langmuir 22:6438, 2006). The principle of our method is to use parallel flows between two immiscible fluids as a pressure sensor. In fact, in a such flow, both fluids flow side by side and the size occupied by each fluid stream depends only on both flow rates and on both viscosities. We use this property to measure the viscosity of one fluid knowing the viscosity of the other one, both flow rates and the relative size of both streams in a cross-section. We showed that using a less viscous fluid as a reference fluid allows to define a mean shear rate with a low standard deviation in the other fluid. This method allows us to measure the flow curve of a fluid with less than 250 μL of fluid. In this paper we implement this principle in a fully automated set up which controls the flow rate, analyzes the picture and calculates the mean shear rate and the viscosity of the studied fluid. We present results obtained for Newtonian fluids and complex fluids using this set up and we compare our data with cone and plate rheometer measurements. By adding a mixing stage in the fluidic network we show how this set up can be used to characterize in a continuous way the evolution of the rheological properties as a function of the formulation composition. We illustrate this by measuring the rheological curve of four formulations of polyethylene oxide solution with only 1.3 mL of concentrated polyethylene oxide solution. This method could be very useful in screening processes where the viscosity range and the behavior of the fluid to an applied stress must be evaluated.     

基于眼睛特征的人脸检测方法*

由于眼球的灰度级较低,而眼球周围白色区域的灰度级较高,因此在其交界处灰度级产生强烈突变。利用这一特征先从图像中找出可能的眼睛对,定位可能的人脸区域,通过计算其对称性来确定各种人脸特征的存在,更进一步验证可能的人脸区域。实验证明,此方法能迅速准确地从复杂背景图像中检测出人脸,而且对多人脸图像同样有效。     

基于多Agent计算机仿真实验平台Swarm的综述*

结合具体实例“热虫实验”,解释了Swarm在人工世界环境下进行计算机仿真模拟的基本思想,探讨了Swarm的主要概念和系统结构;进而以Java语言为例介绍了面向对象思想用于Swarm编程的基本情况,并对Swarm所提供的软件工具包给出了Java形式的详细说明。     

基于VC++复数模板实现一般复矩阵的奇异值分解运算

Ｖｉｓｕａｌ　Ｃ＋＋以其方便的可视化集成编程环境,高效的代码实现功能,强大的基内库以及兼有低级语言可控制硬件操作的优点,成为一般工程项目的首选软件开发平台。涉及信号处理的实际工程常常需要处理复的数字信号,因此Ｖｉｓｕａｌ　Ｃ＋＋下如何实现复数运算是工程技术中软件开发必须面对的问题。该文详细阐述了ＶｉｓｕａｌＣ＋＋中利用复数模板实现复数运算的方法,给出了一些基本复数运算的实现代码;并基于该方法实现了算法已知的一般复矩阵的奇异值分解（ＣＳＶＤ）运算,很好地满足了实际工程信号处理软件模块的需要,证明了该方法的正确性。发现了 Ｖｉｓｕａｌ　Ｃ＋＋５．０和Ｖｉｓｕａｌ　Ｃ＋＋６．０一个声明的复数模板函数在其标准Ｃ＋＋库中没有具体实现,通过编写同名模板函数解决了这一问题。