特定三维人脸建模方法综述

介绍人脸建模的研究背景、研究内容以及研究热点,总结近期三维人脸建模的常用方法及优缺点,展望今后人脸建模的研究方向。三维建模是计算机视觉和计算机图形学领域中一个基本的问题,人脸因其普遍性和特殊性,成为众多研究人员的研究目标。     

基于KPI体系和主题模型的火力发电企业辅助决策系统的实现

针对火力发电企业的生产、经营、燃料和环保的关键绩效指标（KPI）,分别应用同环比分析、趋势分析、杜邦分析、量本利分析、对标分析等模型和方法,采用主题模型的设计思想,实现了火力发电企业辅助决策系统,在电量分析、安全生产、费用监控、节能减排等方面为发电企业提供分析和决策依据,从而在更高层次上提升其生产和经营的管理水平。     

最小通路法在通信保密装备可靠性建模中的应用

针对通信保密装备可靠性建模难度大的问题,提出了一种新的适用于复杂系统的可靠性建模方法一最小通路法。通过在系统拓扑结构图上搜索出所有能够使系统正常工作的最小通路,建立系统的可靠性模型。该方法基于广义的网络拓扑结构,因此网络的源节点和目标节点不必局限于严格的定义,可以随意指定,具有很大的灵活性。实例证明,该方法可行有效。     

基于HLA的海航作战仿真系统设计研究

首先对基于高层体系结构（HLA）的海航作战仿真系统进行了介绍和分析,在分析作战特点的基础上,依据HLA的体系结构规范,构建了海航作战仿真系统的体系结构框架,并利用统一建模语言（UML）,完成了系统对象类和交互类模型设计,研究了仿真成员代码实现的方法,对航空兵作战仿真的进一步研究和系统开发具有一定的借鉴意义。     

Hybrid information retrieval policies based on cooperative cache in mobile P2P networks

The concept of Peer-to-Peer (P2P) has been introduced into mobile networks, which has led to the emergence of mobile P2P networks, and originated potential applications in many fields. However,mobile P2P networks are subject to the limitations of transmission range, and highly dynamic and unpredictable network topology, giving rise to many new challenges for efficient information retrieval. In this paper, we propose an automatic and economical hybrid information retrieval approach based on cooperative cache. In this method, the region covered by a mobile P2P network is partitioned into subregions, each of which is identified by a unique ID and known to all peers. All the subregions then constitute a mobile Kademlia (MKad) network. The proposed hybrid retrieval approach aims to utilize the floodingbased and Distributed Hash Table (DHT)-based schemes in MKad for indexing and searching according to the designed utility functions. To further facilitate information retrieval, we present an effective cache update method by considering all relevant factors. At the same time, the combination of two different methods for cache update is also introduced. One of them is pull based on time stamp including two different pulls: an on-demand pull and a periodical pull, and the other is a push strategy using update records. Furthermore, we provide detailed mathematical analysis on the cache hit ratio of our approach. Simulation experiments in NS-2 showed that the proposed approach is more accurate and efficient than the existing methods.     

话题发现与追踪技术研究

话题发现与追踪以新闻流为处理对象,采用基于事件的信息组织方式进行研究,一直是自然语言处理领域里的热点。该研究借鉴大量相关研究尤其是信息检索中的经典模型和方法,取得了很大成功。首先介绍了话题发现与追踪的主要研究内容、评价方法以及发展历史;然后对其多个研究内容提出一个统一研究框架,并对该框架中的关键技术进行了详细分析;最后指出该领域中的关键问题及难点,并对未来研究做出展望。     

Magnitude bounds of generalized frequency response functions for nonlinear Volterra systems described by NARX model

In order to reveal the relationship between system time domain model parameters and system frequency response functions, new magnitude bounds of frequency response functions for nonlinear Volterra systems described by NARX model are established. The magnitude bound of the nth-order generalized frequency response function (GFRF) can be expressed as a simple n-degree polynomial function of the magnitude of the first order GFRF, whose coefficients are functions of the model parameters and frequency variables. Thus the system output spectrum can also be bounded by a polynomial function of the magnitude of the first order GFRF. These results demonstrate explicitly the analytical relationship between model parameters and system frequency response functions, and provide a significant insight into the magnitude based analysis and synthesis of nonlinear systems in the frequency domain.     

Comment on ‘Frequency domain identification of Wiener models’, by E.W. Bai, Automatica 39 (2003), 1521–1530

A frequency-domain identification method is proposed by Bai (2003) for Wiener systems. The key component is a phase estimator that gives estimates of the linear subsystem phase for different frequencies. These estimates are then used to identify the whole system. In this note, it is shown that the phase estimator is not generally consistent. Consequently, consistency of the overall identification method is in turn not generally guaranteed.     

Numeric and curve parameters for freeform surface feature models

The success of feature modelling systems depends to a large extent on offering user-friendly ways for specifying and varying feature models. In this paper, several new facilities are introduced for this.Numeric and curve parameters are presented for specification and variation of freeform surface feature models. Several properties of the parameters can be defined, such as the direction of evaluation for a curve parameter. In addition to parameters present in features, other parameters can be added to a feature model, including intersection curves between features.To provide these facilities, a new three-level structure is introduced, which includes a partially evaluated model that can capture new generic model entities, including feature intersection curves. The work has been implemented in a prototype surface feature modelling system with functionality for feature class definition, feature model creation, and advanced feature model variation through the new types of parameters.     

基于曲率流的点模型编辑方法*

为了对点模型表面进行保细节的自由形状编辑,提出了一种基于曲率流的点模型形状编辑方法。该方法定义了基于平均曲率流的光顺算子,通过此光顺算子获得点模型不同光滑程度的曲面表示。运用对应曲面上点之间的向量差进行相应几何细节的抽取,在相邻的曲面表示之间将几何细节剥离出来。用户可以在不同的曲面上进行自由形状编辑,而无须关心几何细节。在变形后的曲面上再将相应的几何细节映射回去,实现对模型保细节的变形。实验结果表明该方法是一种有效的点模型造型算法,在变形的同时,有效地保持了模型表面的细节特征。