基于现场总线技术的工业控制系统研究

现场总线是现代工业控制技术的发展方向,对于现场总线来说,其特点是现场通信、现场设备互联,具有较好的互操作性,并且功能模块分散化,同时具有开放式互联网等。本文通过对现场总线技术,以及通信协议进行仔细分析和研究,对几种常用的现场总线进行比较,说明了由其构成的工业控制系统的结构,最后针对CAN总线设计了一种工业控制系统并强调了在设计中所需注意的问题。     

Climate cooperation from Kyoto to Paris: What can be learnt from the CDM experience?

The mitigation of greenhouse gas concentration has become a first-order issue for decision making in environmental sustainability. Countries can meet their mitigation commitments and environmental objectives through multiple instruments. A key role is played by cooperative mechanisms, such as the Clean Development Mechanism (CDM), under the Kyoto Protocol, and a similar mechanism established by the Paris Agreement (Art. 6), whose implementation rules are still under negotiation. However, another form of cooperation was already established under the different framework of the Official Development Assistance (ODA), potentially sharing abatement purposes. This paper aims to compare the mitigation actions implemented either as CDM or ODA projects. We conduct a multi-criteria econometric analysis, based on an originally created, harmonised dataset that merges renewable energy CDM projects and comparable ODA projects to investigate the role of the institutional framework in influencing the effectiveness of reducing emissions worldwide. Results show that the Kyoto Protocol had a positive impact in terms of cost-effectiveness for renewable energy projects and that it stimulated policy actions for environmental sustainability. Accordingly, in view of the implementation of Article 6 of the Paris Agreement, it is extremely important both to look to the past to draw lessons from Kyoto's successes and failures and to apply multi-criteria decision-making approaches for the design of environmental policies.     

Profibus-DP现场总线通信接口设计

PROFIBUS已经成为一种国际化的、开放的现场总线标准。文中在阐述现场总线PROFIBUS的基本特性和SIEMENS公司提供的PROFIBUS-DP专用协议芯片SPC3的基础上,探讨了用SPC3开发PROFIBUS-DP智能化从站通信接口的方案,并给出了该方案的硬件实现方法。     

Trading under the proof-of-stake protocol – A continuous-time control approach

We develop a continuous-time control approach to optimal trading in a Proof-of-Stake (PoS) blockchain, formulated as a consumption-investment problem that aims to strike the optimal balance between a participant's (or agent's) utility from holding/trading stakes and utility from consumption. We present solutions via dynamic programming and the Hamilton–Jacobi–Bellman (HJB) equations. When the utility functions are linear or convex, we derive close-form solutions and show that the bang-bang strategy is optimal (i.e., always buy or sell at full capacity). Furthermore, we bring out the explicit connection between the rate of return in trading/holding stakes and the participant's risk-adjusted valuation of the stakes. In particular, we show when a participant is risk-neutral or risk-seeking, corresponding to the risk-adjusted valuation being a martingale or a sub-martingale, the optimal strategy must be to either buy all the time, sell all the time, or first buy then sell, and with both buying and selling executed at full capacity. We also propose a risk-control version of the consumption-investment problem; and for a special case, the “stake-parity” problem, we show a mean-reverting strategy is optimal.     

对计算机嵌入式实时操作系统的研究及分析

在信息迅速发展的今天,计算机信息技术已经成为一种主导技术,信息产业也成为主导的产业,信息产业已经成为当今社会一种新的经济增长点。信息产业在与计算机技术和通信产业相结合的基础上,迅速的发展成一门庞大的学科。对计算机嵌入式实时操作系统的研究及分析,已成为一种必须的解决的重要课题,以适应当今社会的高速发展。下面就针对如何做好对计算机嵌入式实时操作系统的研究及分析谈谈自己的感受和体会。     

用自由口模式实现S7-200系列PLC与IPC的通讯

介绍了如何用自由口模式实现西门子公司的S7 200系列PLC与上位机的通讯,给出了一种简单的用户自定义协议,着重介绍了上,下位机之间具体通讯过程的实现,并给出了部分程序和流程图。该方案具有硬件简单、使用灵活的特点,对中小型控制系统实现通讯有一定的参考价值。     

中继终端设备的天地网关功能设计与性能测试

近年来,空间网络协议大力发展,CCSDS空间网络协议体系已成为事实上的标准。基于跟踪与数据中继卫星系统（TDRSS）地面站中低速中继终端设备进行相应改造,增加网关路由板卡,加载CCSDS空间传输协议软件,将原来的中低速中继终端设备改造成带有路由网关功能的中低速中继终端设备。在此基础上,采用两台增加路由网关功能的中低速中继终端设备以及信道模拟器搭建天地网络演示验证系统,并分别对采用TCP协议和PEP增强协议作为传输层协议的HTTP应用进行了性能分析比对,证明PEP增强协议更能适应天地网络传输。     

Ad Hoc 网络中的路由技术

作为下一代网络的重要组成部分,Ad Hoc网是目前的一个重要研究热点。根据Ad Hoc网络的特点,总结了Ad Hoc网中的路由技术。从路由查找和维护的角度分析和归纳了网络中关于单播路由、组播路由和QoS路由等的技术特点,指出了不同协议及算法的设计思路和解决策略,为寻求和设计更为高效的适合自组网特点的新型路由技术奠定基础。     

无线网络中的G3传真通信技术

无线通信技术已经广泛应用于社会各个方面,但是基于无线网络的传真应用却是刚刚起步。介绍了在CDMA、GSM等无线网络中的传真通信技术,研究设计了基于GSM的无线传真通信规程,并通过实验完成了无线传真终端与普通G3传真机的传真通信。     

基于SCPS协议的快速自组织可重构天基信息网组网

根据快速自组织天基信息网的特点,设计了组网模型,分析了所需协议的结构,提出了基于空间通信协议规范（SCPS）协议的快速自组织天基信息网的组网抗毁策略,优化了天基信息系统运行效率,提高了其生存能力。