系统资源受限环境下的证书解析方法研究

证书解析是证书应用的基础,目前已知的证书解析操作均运行于操作系统应用层。这种证书解析方法尽管具有较强的通用性,但代码复杂,占用系统资源较多。本文在研究证书格式的基础上,给出了一种适用于操作系统内核层、嵌入式系统等资源受限环境的解析方法,具有实现简单、占用资源少、运行速度快等特点。     

LM3S9896的μDMA高速网络驱动程序设计

针对Cortex—M3核的微控制器LM3S9896,提出了一种基于tzDMA的高速网络驱动程序的设计方案。在简要介绍LM3S9896的以太网控制器、网络驱动程序的作用后,对该网络驱动程序设计的各个部分进行了详细描述,包括网络驱动初始化程序、数据包发送程序、数据包接收程序和中断处理程序等。     

μC／OS—III为缩短中断关闭时间作出的改进

本文介绍了实时内核的中断机制,研究了μC／OS-III为缩短中断关闭时间做出的改进。通过对比μc／OS—II以及μC／OS—III的中断管理办法,分析μC／OS—III在哪些方面作出了改进。这些改进使得μC／OS—III的实时性能得到显著提升,使得μC／OS—III的中断关闭时间大大缩短。     

A grid-based clustering algorithm for wild bird distribution

Advanced satellite tracking technologies provide biologists with long-term location sequence data to understand movement of wild birds then to find explicit correlation between dynamics of migratory birds and the spread of avian influenza. In this paper, we propose a hierarchical clustering algorithm based on a recursive grid partition and kernel density estimation (KDE) to hierarchically identify wild bird habitats with different densities. We hierarchically cluster the GPS data by taking into account the following observations: 1) the habitat variation on a variety of geospatial scales; 2) the spatial variation of the activity patterns of birds in different stages of the migration cycle. In addition, we measure the site fidelity of wild birds based on clustering. To assess effectiveness, we have evaluated our system using a large-scale GPS dataset collected from 59 birds over three years. As a result, our approach can identify the hierarchical habitats and distribution of wild birds more efficiently than several commonly used algorithms such as DBSCAN and DENCLUE.     

Robust preparation of four-qubit decoherence-free states for superconducting quantum interference devices against collective amplitude damping

Based on the quantum Zeno dynamics, we present an approach for deterministic preparation of arbitrary four-qubit decoherence-free state of superconducting quantum interference devices with respective to collective amplitude damping in a decoherence-free way, namely, not only the form of the target state is free of decoherence, but also the whole process for preparation. The operation is fast and convenient since we only need to manipulate three weak laser pulses sequentially. Other decoherence effects such as cavity decay and the spontaneous emission of qubits are also taken into account in virtue of master equation, and the strictly numerical simulation signifies the final fidelity is high corresponding to the current experimental technology.     

餐厅网络运营服务系统

本文介绍了××餐饮管理服务有限公司酒店对网络运营管理服务信息系统的开发过程,包括软件工程的需求分析、系统功能结构设计、数据库设计以及调试在内的所有开发过程。本文中所论述的网络运营管理服务信息系统是一个将业务处理从纯人工操作转换成人工与计算机共同处理的一个实例,并对转换过程进行了详细策划,可作为同类计算机网络运营管理服务信息系统的应用参考。     

基于Java技术网络电话系统的设计与设想

基于Java技术的软件开发,应用RMI,JDBC等技术实现一个小型网络电话系统,应用ACCESS数据库记录相关数据,使用JDBC实现Java程序与数据库的连接,通过对端口的设计,实现两台计算机之间的模拟通讯。     

规则与实例相结合的公文标题汉英机器翻译系统

随着我国对外开放的不断深入,越来越多的外国朋友希望了解中国的方针政策,而公文是贯彻执行我国方针政策的有力工具,标题作为公文的一大要素,起着点明主题的作用。因此,在信息公开化不断发展的今天,政府网站或公报不仅需要刊载中文版的信息,而且有必要刊载英文版的。鉴于行政机关法定公文标题格式固定、要素稳定的特点,本文基于自建小型公文标题语料库,经分析得出公文标题的表达式和10个词表,然后结合实例,设计一公文标题翻译系统。这只是行政机关公文翻译系统的初步探索,希望能为减轻文秘人员的工作负担、最终实现公文的语言自由转换提供一点帮助。     

QuickBird and Hyperion data analysis of an invasive plant species in the Galapagos Islands of Ecuador: Implications for control and land use management

In the Galapagos Islands of Ecuador, one of the greatest threats to the terrestrial ecosystem is the increasing number and areal extent of invasive species. Increased human presence on the islands has hastened the introduction of plant and animal species that threaten the native and endemic flora and fauna. Considerable research on invasive species in the Galapagos Islands has been conducted by the Charles Darwin Foundation. We complement that work through a spatially- and spectrally-explicit satellite assessment of an important invasive plant species (Psidium guajava — guava) on Isabela Island that integrates diverse remote sensing systems, data types, spatial and spectral resolutions, and analytical and image processing approaches. QuickBird and Hyperion satellite data are processed to characterize the areal extent and spatial structure of guava through the following approaches: (1) QuickBird data are classified through a traditional pixel-based approach (i.e., an unsupervised classification approach using the ISODATA algorithm), as well as an Object-Based Image Analysis (OBIA) approach; (2) multiple approaches for spectral “unmixing” of the Hyperion hyper-spectral data are assessed to construct spectral end-members from QuickBird data using linear and non-linear mixture modeling approaches; and (3) landscape pattern metrics are calculated and compared for the pixel-based, object-based, and spectral unmixing approaches. The spectral–spatial characteristics of guava are interpreted relative to management strategies for the control of guava and the restoration of natural ecosystems in the Galapagos National Park.