Industrial energy efficiency: the need for investment decision support from a manager perspective

Global competition, commitment to the Kyoto Protocol and a deregulated, integrated European electricity market will in all probability increase the demand for energy efficiency on the part of companies in Sweden. Investment decisions are an important part of meeting the new demands, because they decide the future efficiency of industrial energy systems. The objective of this study is to investigate, from a managerial perspective, the need to improve decision support in some industries, which can help to facilitate and improve investment decisions concerning energy efficiency. This work has been conducted through in-depth interviews with representatives for a number of energy-intensive companies and non-energy-intensive companies from different sectors. One need that was identified was the improvement of working methods in order to support the decision-making process. Here, external players seem to be playing an increasingly important role. Access to correct information, better follow-up activities, and transparent, understandable calculations are also considered to be important. The study will form the foundation for subsequent work on decision support and energy efficiency in industry.     

互联网下会计信息系统内部控制研究

网络会计给企业带来利益的同时 ,也给企业内部控制带来新问题。讨论了建立适应互联网环境下会计信息系统的内部控制 ,其措施应基于企业内部和外部的组织与管理、系统开发及网络系统安全控制等方面的问题     

以外供液氮替代膨胀机的深度冷冻循环

介绍空分制氮装置采用膨胀机循环与液氮循环的两种工艺流程及能量平衡 ,示出了两种循环的实例比较。指出外供液氮可以作为冷源替代膨胀机 ,且单耗低、操作更方便 ,设备维护量更小、氮气提取率更高     

Control of Wind-Induced Self-Excited Oscillations by Transfer of Internal Energy to Higher Modes of Vibration. II: Application to Taut Cables

In Part I of this paper, a theoretical basis is presented using a two-degrees-of-freedom model. In this second part of the study, the passive control and the two types of semiactive controls introduced in Part I are examined numerically for a taut cable experiencing wind-induced galloping motion. The passive and the semiactive control schemes for taut cables show a good similarity with the results obtained for the two-degrees-of-freedom model. The potential of using these control schemes in practical applications to flexible structures is demonstrated.     

考虑电气价因素的压气站运行优化模型研究

针对压气站运行优化模型，引入了两个开关型变量：压气站开关变量和压缩机开关变量：同时还引入了考虑提供单位功率所需的能耗量两个变量。其优点是考虑了压气站越站和站内压缩机停机的情形，而且还直接引入与价格相关的变量，使得模型在运行优化的结果上更能体现某种方案的经济性，这对于管道运行商来说，更具有直观性。     

Location and calculation-free node-scheduling schemes in large wireless sensor networks

In wireless sensor networks that consist of a large number of low-power, short-lived, unreliable sensors, one of the main design challenges is to obtain long system lifetime without sacrificing system original performance (sensing coverage and sensing reliability). To solve this problem, one of the potential approaches is to identify redundant nodes at the sensing interface and then assign them an off-duty operation mode that has lower energy consumption than the normal on-duty mode. In our previous work [J. Wireless Commun. Mobile Comput. 3 (2003) 271; Processing of ACM Wireless Sensor Network and Application Workshop 2002, September 2002], we proposed a node-scheduling scheme, which can provide a 100% sensing coverage preservation capability. This, however, requires each node to be aware of its own and its neighbors’ location information. Also, in that scheme, each node has to do accurate geometrical calculation to determine whether to take an off-duty status. In this paper, we propose and study several alternative node-scheduling schemes, which cannot completely preserve the original system coverage, but are nonetheless light-weighted and flexible compared with the previous one. Our simulation results compare these schemes with the previous one and demonstrate their effectiveness.     

基于嵌入式以太网的异步电机矢量控制系统体系结构设计

为了实现异步电机现场控制与上层管理的无缝集成，提出在通用变频器一异步电动机调速系统的基础上，采用基于ARM7TDMI核的微控制器和以太网控制芯片，实现异步电机的网络化控制。详细介绍了该系统的体系结构设计方案。     

The Role of Network Topologies in the Optical Core of IP-over-WDM Networks with Static Wavelength Routing

In this paper, we present a performance analysis of network topologies for the optical core of IP-over-WDM networks with static wavelength routing. The performance analysis is focused on regular degree four topologies, and, for comparison purposes, degree three topologies are also considered. It is shown that the increase of the nodal degree from three (degree three topology with smallest diameter) to four (degree four topology with smallest diameter) improves the network performance if a larger number of wavelengths per link is available. However, the influence of wavelength interchange on the nodal degree gain is small. The performance of regular degree four topologies with smallest diameter is also compared with the performance of mesh–torus topologies (which are also degree four topologies), and it is shown that the blocking probability of degree four topologies with smallest diameter is about two orders of magnitude lower than the blocking probability of mesh–torus topologies. It is also presented a performance comparison of WDM-based networks with nodal degrees ranging from two to five and it is shown that the increase of the nodal degree from two to three leads to high nodal degree gains, while de increase of the nodal degree from four to five leads to low nodal degree gains. These results show that degree three and degree four topologies are very attractive for use in the optical core of IP-over-WDM networks.     

电子数据交换EDI

介绍了电子数据交换的概念、EDI系统的组成，阐述了传统交易模式与EDl交易模式的区别，分析了实现EDI的三项挂心技术，介绍了EDl与Internet的关系、实施EDI的效益以及EDI的应用与EDI的前景。     

基于面像识别技术的公安网上追逃系统

研究了公安网上追逃系统的体系结构和系统的程序流程，阐述了ASP COM 后台比对服务的3层B／S模式面像网上比对的实现方法，最后给出系统的性能指标和特点。