JBEAM: multiscale curve coding via beamlets.

A multiscale coder for curves and boundaries is presented. It utilizes a multiscale structure--beamlets--that is designed primarily for linear and curvilinear features. The coder is composed of three main components: 1) a rate-distortion optimized beamlet-based representation, 2) a tree-based coding from a beamlet representation to a symbol stream, and 3) an entropy coder. This coder is named "JBEAM." Taking advantage of its multiscale property, we utilized tree-based coding to make it progressive. The derived coder has a low order of computational complexity. Simulations demonstrate an advantage over the state-of-the-art industrial standard: JBIG 2. A software package, which includes an implementation of JBEAM, is made available. Variations and potential improvements of this method will be discussed. This work may inspire more activities in this line of research, improving curve coding.     

Minimizing total completion time for UET tasks with release time and outtree precedence constraints

Brucker et al. (Math Methods Oper Res 56: 407–412, 2003) have given an O(n ²)-time algorithm for the problems , outtree and , outtree . In this note, we show that their algorithm admits an O(n log n)-time implementation.     

Initial stages of Ti growth on diamond (100) surfaces: from single adatom diffusion to quantum wire formation

Using first-principles total energy calculations within density functional theory, we investigate the energetics, kinetics, and transport properties of Ti on clean and hydrogen-terminated diamond (100)-2x1 surfaces at increasing Ti coverages. On a clean surface, an isolated Ti adatom prefers to adsorb on top of a C-C dimer row, and also diffuses faster along the dimer row direction. As the Ti coverage increases, the preferred adsorption site converts from an atop site to a site located between the dimer rows. Passivation of the surface at the monohydride coverage not only greatly enhances the Ti mobility, but also weakens the diffusion isotropy. Based on these energetic and kinetic characteristics, we propose a viable approach to fabricate ideal Ti quantum wires on hydrogen-terminated diamond substrates.     

Attosecond pulse extreme-ultraviolet photoionization in a two-color laser field

Attosecond-pulse extreme-ultraviolet (XUV) photoionization in a two-color laser field is investigated. Attosecond pulse trains with different numbers of pulses are examined, and their strong dependence on photoelectronic spectra is found. Single-color driving-laser-field-assisted attosecond XUV photoionization cannot determine the number of attosecond pulses from the photoelectronic energy spectrum that are detected orthogonally to the beam direction and the electric field vector of the linearly polarized laser field. A two-color-field-assisted XUV photoionization scheme is proposed for directly determining the number of attosecond pulses from a spectrum detected orthogonally.     

可视电话系统中视频模块的软件实现

介绍了可视电话系统中视频模块的软件实现,包括用ＭＭＸ实现视频实时编解码、对“块效应”后处理以提高视频主观质量、以及视频采集和视频显示。     

自动交换光网络的生存性及保护恢复

自动交换光网络(ASON)是当前光传输领域的研究热点，其中保护恢复策略将为增强网络生存性奠定新的基石。本首先介绍了ASON中的保护和恢复机制以及它们各自的特点。并在此基础上讨论它们与传统SDH网络保护恢复机制比较所表现出的几点优势，最后，针对ASON的传送平面和控制平面的保护恢复提出主要的技术要求，这些要求将有助于保证ASON在生存性方面优势的真正实现。     

YAP系列晶体光纤的生长和LD泵浦的Nd:YAP单晶光纤激光器

本文叙述了YAP系列晶体光纤的优点和生长方法;用激光加热小基座法生长出直径范围为50～500μm,直径波动<±1％/cm的YAP系列晶体光纤。研制成用LD泵浦的单晶Nd∶YAP光纤激光器,输出为1.0795μm波长的线偏光,最大输出功率为1mW。     

变参数自由电子激光器中电子的随机运动

本文讨论了变参数自由电子激光器中电子的运动,指出部分电子的轨道是非周期性,随机型的。随着参数变化率增大,随机轨道电子所占比例愈大。文中还提出了当随机运动较强时统计描述的方法,以及随机运动对效率的影响。 关键词：     

FPCS——一种适用于积木块方式的布局及平面规划系统

本文简述了一种分级式的自下而上结群和自上而下分划定位相结合的全定制方式的积木块(building block)布局及平面规划(floorplanning)系统.本方法基于积木块的尺寸、形状、连接状况、引线位置以及芯片引线端等的要求逐级优化组合若干种积木块组,并且根据工艺条件进行了布线区面积估计,以便得到较好的布局结果.如果积木块的尺寸或其长宽比可以改变,则本系统可改变其尺寸及形状从而优化布局结果.由于采用了多种有效的实用方法,并把它们有机地统一在系统中,因此使布局能在基本满足用户要求的条件下,做到和布线结果基本匹配.实验结果表明,这种方法是令人满意的.