Analysis of the Datagram Congestion Control Protocol’s connection management procedures using the sweep-line method

State space explosion is a key problem in the analysis of finite state systems. The sweep-line method is a state exploration method which uses a notion of progress to allow states to be deleted from memory when they are no longer required. This reduces the peak number of states that need to be stored, while still exploring the full state space. The technique shows promise but has never achieved reductions greater than about a factor of 10 in the number of states stored in memory for industrially relevant examples. This paper discusses sweep-line analysis of the connection management procedures of a new Internet standard, the Datagram Congestion Control Protocol (DCCP). As the intuitive approaches to sweep-line analysis are not effective, we introduce new variables to track progress. This creates further state explosion. However, when used with the sweep-line, the peak number of states is reduced by over two orders of magnitude compared with the original. Importantly, this allows DCCP to be analysed for larger parameter values. Somsak Vanit-Anunchai was partially supported by an Australian Research Council Discovery Grant (DP0559927) and Suranaree University of Technology. Guy Edward Gallasch was supported by an Australian Research Council Discovery Grant (DP0559927).     

Real-time measurement of pointing action by using DSP

This paper presents an approach of measuring in real-time the vector of finger that is pointing to an object. DSP is used in the operation processing unit in order to do the real-time processing. The steps include the extraction of flesh-colored regions from an image, the labeling of the flesh-colored regions, and the detection of two characteristic positions on the finger so that the direction that the finger is pointing at will be calculated. The entire process takes about 29 msec, which makes it possible to have the frame rate of 34 fps. With this frame rate, this measurement approach is considered real-time and promising to be merged into other application systems. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Entrainment and musicality in the human system interface

What constitutes our human capacity to engage and be in the same frame of mind as another human? How do we come to share a sense of what ‘looks good’ and what ‘makes sense’? How do we handle differences and come to coexist with them? How do we come to feel that we understand what someone else is experiencing? How are we able to walk in silence with someone familiar and be sharing a peaceful space? All of these aspects are part of human ‘interaction’. In designing interactive technologies designers have endeavoured to explicate, analyse and simulate, our capacity for social adaptation. Their motivations are mixed and include the desires to improve efficiency, improve consumption, to connect people, to make it easier for people to work together, to improve education and learning. In these endeavours to explicate, analyse and simulate, there is a fundamental human capacity that is beyond technology and that facilitates these aspects of being, feeling and thinking with others. That capacity, we suggest, is human entrainment. This is our ability to coordinate the timing of our behaviours and rhythmically synchronise our attentional resources. Expressed within the movements of our bodies and voices, it has a quality that is akin to music. In this paper, disparate domains of research such as pragmatics, social psychology, behaviourism, cognitive science, computational linguistics, gesture, are brought together, and considered in light of the developments in interactive technology, in order to shape a conceptual framework for understanding entrainment in everyday human interaction.     

Effects of Y and Ce on Microstructures and Properties of Nb-Si System Composites

The effects of yttrium and cerium on microstructures and properties of Nb-Si system composites were investigated by scanning electron microscopy( SEM), energy dispersive spectrum(EDS), X-ray diffraction(XRD) and high temperature oxidation experiments.It is found that the coarse primary silicide phase became finer and more homogeneous with Y and Ce addition.The results of high temperature oxidation experiments show that the oxidation rates of NbSi system composites with an appropriate amount of Y and Ce decrease compared with those of alloys without Y or Ce addition, and oxidation products mainly distribute along the phase boundaries between the Nb solid solution and silicide.     

Cyclic oxidation response of multiphase niobium-based alloys

Cyclic oxidation tests were performed on multiphase Nb-based alloys containing silicide, Laves, and Nb solid solution phases. In particular, the oxidation resistance of six alloys with various compositions (Nb, Ti, Hf, Cr, Ge, and Si) and microstructures was characterized by thermal cycling from ambient temperature to a peak temperature that ranges from 900 °C to 1400 °C. Weight change data were obtained and the corresponding spalled oxides were collected and identified by X-ray diffraction. The results indicated that Nb-based alloys formed a mixture of CrNbO₄, Nb₂O₅, and Nb₂O₅ · TiO₂, with possibly small amounts of SiO₂ or GeO₂. The oxidation resistance was improved when CrNbO₄ formed instead of Nb₂O₅ and Nb₂O₅ · TiO₂. These results were used to assess the influence of microstructure and composition on the oxidation resistance of multiphase Nb-based alloys.     

基于嵌入式Linux的远程数据采集系统

以嵌入式微控制器为核心,将传感器网络收集来的数据通过无线电发射机发送到远程接收机,从而实现远程数据采集.系统的优势是充分利用了短波无线链路资源,适合于工作在无人区等场合.以ARM7为控制器,功耗小,性能稳定,维护方便;通信方式采用串口通信,连接线少,实现相对简单.系统设计主要应用嵌入式μCLinux系统设计、无线电发射、调制解调器等方面的知识,文中给出了调制解调器拨号协议、系统原理和软件流程等.     

WCDMA系统中SPT数字滤波器的一种设计方法

相对于传统的数字滤波器实现方法,符号的2次幂和(SPT)滤波器用移位寄存器替代乘法器,因而资源消耗少、速度快,更加适于专用集成电路(ASIC)设计.介绍了一种适用于宽带码分多址(WCDMA)前向信道中给定基带成形滤波器单位脉冲响应后设计SPT滤波器的方法.相对于传统的理想SPT系数优化方法,此方法更适于给定单位脉冲响应后SPT滤波器的设计,计算复杂度低;仿真结果显示,相对于更加简单的四舍五入方法,此算法在性能上又有可观的增益.     

Thomas Fincke und die <Emphasis Type="Italic">Geometria rotundi</Emphasis>

Thomas Fincke (January 6^th, 1561–April 24^th, 1656), born in Flensburg (Germany), was one of the very most important and significant scientists in Denmark during the seventeenth century, a mathematician and astrologer and physician in the beginning of modern science, a representative of humanism and an influentual academic organizer. He studied in Strasbourg (since 1577) and Padua (since 1583) and received his M.D. in Basel (1587), he practised as a physician throughout his life (since 1587 or 1590) and became a professor at Copenhagen (1591). But he was best known because of his Geometriae rotundi libri XIIII (1583), a famous book on plane and spherical trigonometry, based not on Euclid but on Petrus Ramus. In this influentual work, in which Fincke introduced the terms tangent and secant and probable first noticed the Law of Tangents and the so-called Newton-Oppel-Mauduit-Simpson-Mollweide-Gauss-formula, he showed himself to be „abreast of the mathematics of his time“.