C49 defect influence on the C49–C54 transition

The C49–C54 transformation has been studied in TiSi₂ thin films having different concentration of defects. The defect concentration in the C49 phase has been varied using different thermal processes in the 460–540 °C temperature range; in fact, the defect concentration decreases with increasing the temperature and/or the duration of the thermal process as attested by the large variation of the silicide residual resistivity at 4 K. The kinetics of the transformation at 650 °C has been followed by in situ resistivity measurements and, for each sample, the transition time decreases as the defect concentration in the metastable phase decreases.     

A performance study for IPv4–IPv6 translation in IP multimedia core network subsystem

A Next Generation Network (NGN) is an advanced, packet‐based network that exploits broadband and QoS‐enabled transport technologies for enabling multimedia services. In NGNs, the principles and requirements of IP Multimedia Sub‐system (IMS), which are used to deliver the desired benefits, should be carefully examined and studied. Internet Protocol version 6 (IPv6) is adopted by Third‐generation Partnership Project (3GPP) to solve address storage problem and provide new features (e.g. plug‐and‐play and mobility) for IMS. However, in the early stage of IPv6 deployment, the existing Voice‐over‐IP (VoIP) networks support Internet Protocol version 4 (IPv4) only. For IPv4–IPv6 interworking between IMS and the existing VoIP networks, the IMS‐Application Level Gateway (IMS‐ALG) and the Transition Gateway (TrGW) are proposed to translate Session Initiation Protocol (SIP) and Real‐time Transport Protocol (RTP) packets, respectively. In this paper, we focus on the IPv4–IPv6 translation for RTP packets, which is the bottleneck of VoIP performance. Specifically, we developed a TrGW called National Information and Communications Initiative (NICI)‐TrGW. In NICI‐TrGW, we perform IPv4–IPv6 translation at the Linux kernel and adjust the header room of kernel‐level packet buffer for each packet to reduce memory‐copy operations. We evaluate the performance of NICI‐TrGW and the existing solutions by using the SmartBits. Our study indicates that NICI‐TrGW outperforms the existing solutions in terms of three different output measures including packet loss rate, maximum throughput, and average latency. Copyright © 2009 John Wiley & Sons, Ltd.     

基于分辨关系的决策树构建算法

针对完全以核属性为首选构建决策树算法的不足,本文以粗糙集的分辨关系为基础,提出以决策属性的分辨量和分辨类别两个参数确定条件属性的重要性,择优自顶向下构造决策树.该算法的优点在于算法简洁有效和时空复杂度低.实例分析的结果表明,该方法能获得更为简洁有效的决策树.     

模拟电路软故障诊断的研究

分析了模拟电路软故障诊断的重要性及现有的各种软故障诊断方法。对模拟电路软故障诊断字典法中基于支路屏蔽原理、电路参数随元件参数变化轨迹、节点电压灵敏度序列守恒定理和节点电压增量关系方程的四个研究方向各自的基本原理和优缺点进行了探讨;介绍了基于神经网络,结合模糊理论、小波变换的现代模拟电路软故障诊断的两个方向的研究现状;同时从通用的软故障诊断方法、大规模模拟电路的诊断策略和数模混合集成电路的诊断需求三方面指出了模拟电路软故障诊断的发展趋势和亟待解决的问题。     

一种复杂过程与复合对象三维建模的实现方法

伴随着虚拟现实技术研究的深入和应用的推广,建模方法作为核心内容也会应用于越来越复杂的系统。现有的建模技术将模型,运动和模型与周围环境的关系相互孤立,这不利用高效和快捷地实现复杂系统。针对这些问题,文章首先使用过程建模方法对复杂系统层次化,然后提出关系建模方法对模型,运动和关系建立标准结构,最后针对复杂过程和复合对象两种应用提出实现方法,验证了方法的可行性和有效性。     

Modulation instability of dispersion-shifted fiber couplers

The nonlinear coupled-mode equations are rewritten by even and odd modes. We study modulation instability (MI) of dispersion-shifted fiber couplers when either even or odd mode is launched alone by using zero-dispersion waveleng threlatively long (quasi-cw) pulses. The result shows that there are new types of MI in both the normal-dispersion and the anomalous-dispersion regimes. MI is concerned with forth-order dispersion and has no relation with third-order dispersion.Quasi-cw can be changed into pulses array under certain conditions. We can extract super short pulse from this. Furthermore,the bandwidth of gain spectra widens and its strength accretes as the input power increases.     

基于公共交通乘车查询系统的数学模型及实现方法

根据北京公交站点分布情况,建立了解决公交拥挤的数学模型,并通过算法和程序化运算,解决了任意两站点间最佳线路的查询问题。在邻接矩阵相乘的过程中,剔除了与现实生活中不相符合的数据,对邻接矩阵中的行和列进行了选择,同时假设出公汽交通阻抗值,从而有效地降低了算法复杂度,并通过对深度优先遍历递归算法的进一步优化再次降低了算法的复杂度。     

Noun Sense Identification of Korean Nominal Compounds Based on Sentential Form Recovery

In a machine translation system, word sense disambiguation has an essential role in the proper translation of words when the target word can be translated differently depending on the context. Previous research on sense identification has mostly focused on adjacent words as context information. Therefore, in the case of nominal compounds, sense tagging of unit nouns mainly depended on other nouns surrounding the target word. In this paper, we present a practical method for the sense tagging of Korean unit nouns in a nominal compound. To overcome the weakness of traditional methods regarding the data sparseness problem, the proposed method adopts complement‐predicate relation knowledge that was constructed for machine translation systems. Our method is based on a sentential form recovery technique, which recognizes grammatical relationships between unit nouns. This technique makes use of the characteristics of Korean predicative nouns. To show that our method is effective on text in general domains, the experiments were performed on a test set randomly extracted from article titles in various newspaper sections.     

基于STL模型的模具型腔分割算法研究及应用

文中以大型混凝土铸件为研究对象,针对人工设计多个模具部件时效率较低的问题,提出一种基于STL模型的型腔分割算法。通过改变STL模型三角面片的方向,将大型构件的STL模型转为模具型腔的STL模型。该算法将模具型腔STL模型数据分类,以三角形面片的法向矢量为判定条件,将同属一个型面的面片分类保存到同一个型面STL模型,从而将一个模具型腔的STL模型分为数个型面STL模型,实现了模具型腔的分割。最后通过两个典型案例中算法设计时间和人工设计时间的对比,证明该算法缩短了模具的设计时间,提高了效率,具有可行性。