基于信息的几个相关问题研究

通过对信息定义的分析比较,对信息的本质和内涵进行了探讨,对信息新的定义进行了尝试,并以信息为理论基础,阐述了数据、信息流、信息场的概念,结合物理场及信息理论对接收信息的度量进行了有益的讨论。     

基于灰关联的彩色图像DWT域信息隐藏算法

基于灰关联的理论思想以及信息隐藏的特点,文中定义了一种新型的灰关联系数的计算方法，并在此定义的基础上提出了一种新的基于彩色图像的信息隐藏算法。该算法通过对原始载体图像DWT域中LH和HL频带的系数进行调整，将秘密数据隐藏到彩色载体图像各个颜色分量的LH和HL频带系数上，根据系数间的灰关联系数大小对秘密信息进行提取，提取时不需要覆盖图像，实现了秘密信息的盲提取。实验结果表明，该算法不仅具有较好的透明性，而且能够对一些常见的攻击如叠加噪声、几何剪切、JPEG压缩、滤波等均具有较好的鲁棒性。     

语言场理论及其在知识发现中的应用

提出了基于认知物理学的语言场理论,给出其基本定义和定理;引入势函数等概念、公式,并把它们分别应用到知识发现的连续属性离散化、聚类两个方面,用以研究解决复杂信息的表示和处理问题。     

基于DOA测量的多目标位置信息场定位精度分析

传统的测向定位理论在对多个目标进行定位时,将测得的DOA参数按目标进行分类是一个难点问题。运用位置信息场定位法不需要对测量参数按目标进行分类,能够同时确定目标数目和多个目标位置。对基于DOA测量的多目标位置信息场定位方法进行了精度分析,通过理论推导得到定位误差的协方差矩阵。在此基础上,利用仿真实验分析了测角精度和基线长度对定位精度的影响,验证了理论推导的正确性,说明了位置信息场定位法是一种有效的多目标定位方法。     

一种新的语言信息计算模型

语言的可计算性问题是理论计算机科学的一个基本问题，字母文字信息的计算模型已经有数十年的历史，而适合汉语信息的计算模型尚未见到．中文信息处理与信息安全的研究迫切需要有适合汉语信息的数学计算模型，提出了两个新的字符串计算模型．在模型1的基础上定义了几个函数运算．利用这两个模型可以将任何汉语信息的处理转换为相应的数值进行处理，对汉语信息处理、汉语程序设计理论的建立和信息安全的研究具有一定的实际意义。     

基于下一代互联网技术的信息网格技术探析

该文首先解释了信息网格的定义,然后与网格计算技术进行了比较,接着讨论了信息网格的发展趋势、关键技术、典型应用,再接着讨论了使用信息网格的注意事项,最后论述了应用信息网格技术的意义,对广大计算机爱好者学习信息网格具有重要的理论和实践指导意义。     

基于势能场模型的RoboCup进攻策略

文中设定了一个势能场来描述比赛的情况。在这样的势能场中，球将向势能降低的方向运动。定义了3种势能场：第一种是对球场定义的；第二种是对每一个球员定义的；最后一种是前两种的结合。在实际中运用的是第一种。把这一方法提供给队员让他们用它来做出判断，他们将依靠判断势能的大小来决定球往哪踢。把这种策略与以往的基于逻辑准则的策略进行了比较，基于势能场的策略在很多情况下会做出更好的决定，在其他情况下也不会比以前的策略更差。     

基于相似性的近似信息系统概念优化算法

在现实的物理世界中，信息系统允许是不完备的、多值的、近似的、离群的，即非定常的（non-deterministic）．本文基于容错粗糙粜理论提出非定常信息系统的形式描述，分析了近似信息系统的六种表现，并给出强相似和弱相似的概念．论文在定义了容错粗糙集的相似性测度的基础上，结合FCA理论对不可定义概念进行了扩展，分别对属性不可定义、对象不可定义和上下文不可定义进行了讨论。并给出了相应的近似系统形式概念的最佳逼近算法．实例仿真表明算法具有较好的时间复杂性．     

基于Poisson方程的曲线形状渐变方法

以定义在分段线性曲线上的离散Poisson方程为理论基础,提出了一种同时适用于平面和空间曲线形状渐变的方法.通过在源曲线和目标曲线上定义局部标架,给出了一种非线性梯度场插值算法,使得源曲线的梯度场逐步过渡到目标曲线的梯度场,所得到的中间梯度场与用户指定的关键节点路径一起输入离散Poisson方程求解得到渐变序列 .该方法不直接插值顶点坐标,而是将源曲线与目标曲线视为定义在公共定义域上的标量场,并在梯度域进行梯度场操纵.对中间帧曲线周长以及平面曲线所包围的内部面积变化的统计表明:该算法尽可能地保持了几何形状的刚性,在中间帧求解的稳定性方面该算法优于同类其他方法.     

云平台下高校教学信息资源整合研究

云计算给信息产业带来一场工业革命,各行各业依托云计算这样一种新型平台,对信息资源进行全面的整合,高校教学信息资源整合一直是教育信息化的重点,本文在结合当前高校教学信息资源整合现状基础上,通过对云计算定义及优势的分析,提出了云平台下整合高校教学信息资源的构想。     

Modeling of reliability with possibility theory

Possibility theory aims at representing and handling uncertain information. An important property of this theory is the ability to merge different data sources in order to increase the quality of the information. Different fusion rules have been defined in the literature, each with its own advantages and drawbacks. However, these rules usually cannot deal rigorously with contradictory data. Therefore, this paper proposes a new approach, based on a fusion rule using a vector expressing the reliability of the data sources. Comparisons are made with classical fusion rules. An algorithm assessing the indexes of reliability of the data used by the new role is given, and an index of the quality of the result is proposed. These three tools define a new method dealing with the reliability of the data in the fusion field, and enable a clear distinction between the data and their quality     

Glyphs for visualizing uncertainty in vector fields

Environmental data have inherent uncertainty which is often ignored in visualization. Meteorological stations and doppler radars, including their time series averages, have a wealth of uncertainty information that traditional vector visualization methods such as meteorological wind barbs and arrow glyphs simply ignore. We have developed a new vector glyph to visualize uncertainty in winds and ocean currents. Our approach is to include uncertainty in direction and magnitude, as well as the mean direction and length, in vector glyph plots. Our glyph shows the variation in uncertainty, and provides fair comparisons of data from instruments, models, and time averages of varying certainty. We also define visualizations that incorporate uncertainty in an unambiguous manner as verity visualization. We use both quantitative and qualitative methods to compare our glyphs to traditional ones. Subjective comparison tests with experts are provided, as well as objective tests, where the information density of our new glyphs and traditional glyphs are compared. The design of the glyph and numerous examples using environmental data are given. We show enhanced visualizations, data together with their uncertainty information, that may improve understanding of environmental vector field data quality     

Intensional answers to database queries

In addition to data, database systems store various kinds of information about their data. Examples are: class hierarchies, to define the various data classes and their relationships; integrity constraints, to state required relationships among the data; and inference rules, to define new classes in terms of known classes. This information is often referred to as intensional information (the data are referred to as extensional information). There have been several independent research works that suggested ways by which intensional information may be used to improve the conventional (extensional) database answers. Although each of these efforts developed its own specific methods, they all share a common belief: database answers would be improved if accompanied by intensional statements that describe them more abstractly. We study and compare the various approaches to intensional answers by using various classifications; we examine their relative merits with regard to key aspects; we discuss remaining issues; and we offer new research directions     

A new vector field distance transform and its application to mesh processing from 3D scanned data

In this paper we define a new 3D vector field distance transform to implicitly represent a mesh surface. We show that this new representation is more accurate than the classic scalar field distance transform by comparing both representations with an error metric evaluation. The widely used marching cube triangulation algorithm is adapted to the new vector field distance transform to correctly reconstruct the resulting explicit surface. In the reconstruction process of 3D scanned data, the useful mesh denoising operation is extended to the new vector field representation, which enables adaptive and selective filtering features. Results show that mesh processing with this new vector field representation is more accurate than with the scalar field distance transform and that it outperforms previous mesh filtering algorithms. Future work is discussed to extend this new vector field representation to other mesh useful operations and applications.     

A congruence relation for sPBC

In this paper we define a congruence relation for regular terms of sPBC (stochastic Petri Box Calculus), by means of which we identify those processes that have the same behaviour, not only in terms of the multiactions that they can perform, but also taking into account the stochastic information that they have associated. In order to define this equivalence relation we have to define an adequate semantics for the synchronization operator, as well as a new labelled transition system for regular terms of sPBC.     

Exploiting geographic references of documents in a geographical information retrieval system using an ontology-based index

Both Geographic Information Systems and Information Retrieval have been very active research fields in the last decades. Lately, a new research field called Geographic Information Retrieval has appeared from the intersection of these two fields. The main goal of this field is to define index structures and techniques to efficiently store and retrieve documents using both the text and the geographic references contained within the text. We present in this paper two contributions to this research field. First, we propose a new index structure that combines an inverted index and a spatial index based on an ontology of geographic space. This structure improves the query capabilities of other proposals. Then, we describe the architecture of a system for geographic information retrieval that defines a workflow for the extraction of the geographic references in documents. The architecture also uses the index structure that we propose to solve pure spatial and textual queries as well as hybrid queries that combine both a textual and a spatial component. Furthermore, query expansion can be performed on geographic references because the index structure is based in an ontology.     

基于有向关联信息的知识约简

关联信息是度量两个定性变量之间非线性关系的一个统计量。论文定义了信息系统以及目标信息系统属性之间的有向关联信息,用来度量信息系统以及目标信息系统属性之间的关联程度,基于此给出信息系统以及目标信息系统的知识约简一种新的判定定理。最后以信息系统以及不协调目标信息系统知识约简的实例证明这种知识约简是简单有效的。     

自然语言处理中词语上下文有效范围的定量描述

词语的上下文（context）是语料库语言学中自然语言知识获取和解决自然语言处理中多种实际应用问题必须依靠的资源和基础,但上下文“窗口”开多大为宜呢？为克服当前仅凭主观经验或通过某一特定应用问题中最终结果正确率界定上下文有效范围的不足,我们在引入信息增益方法确定上下文各位置的信息量后,构造上下文位置信息量函数,最终通过多项式积分确定85％信息量的上下文边界,即汉语核心词语最近距离[－8,＋9]和英文[－16,＋13]位置之间的上下文范围,该文的结果对上下文在自然语言处理中的价值和作用提出了一个具有统计意义的量化解释。     

结合最大熵模型和tag 特征的混合推荐系统

由于用户数目的不断增多以及信息量的快速膨胀,传统协同过滤（CF）中的数据矩阵稀疏性问题显得愈为突出。为此我们提出了一种新的混合推荐方法。首先,我们在最大熵模型下综合考虑tag信息和rating信息作为约束条件,然后分别针对tag信息和rating信息定义相关的特征并且计算其相应的权重,最后利用先前计算出的权重预测当前用户对于目标项目的评分概率分布,并且选出概率最大的作为预测评分。实验证明,该方法能有效提升推荐系统的准确率。