Short-term scheduling of crude oil operations in refinery with high-fusion-point oil and two transportation pipelines

In some refineries, storage tanks are located at two different sites, one for low-fusion-point crude oil and the other for high one. Two pipelines are used to transport different oil types. Due to the constraints resulting from the high-fusion-point oil transportation, it is challenging to schedule such a system. This work studies the scheduling problem from a control-theoretic perspective. It proposes to use a hybrid Petri net method to model the system. It then finds the schedulability conditions by analysing the dynamic behaviour of the net model. Next, it proposes an efficient scheduling method to minimize the cost of high-fusion-point oil transportation. Finally, it gives a complex industrial case study to show its application.     

Resource conflict detection and removal strategy for nondeterministic emergency response processes using Petri nets

Correctness of an emergency response process specification is critical to emergency mission success. Therefore, errors in the specification should be detected and corrected at build-time. In this paper, we propose a resource conflict detection approach and removal strategy for emergency response processes constrained by resources and time. In this kind of emergency response process, there are two timing functions representing the minimum and maximum execution time for each activity, respectively, and many activities require resources to be executed. Based on the RT_ERP_Net, the earliest time to start each activity and the ideal execution time of the process can be obtained. To detect and remove the resource conflicts in the process, the conflict detection algorithms and a priority-activity-first resolution strategy are given. In this way, real execution time for each activity is obtained and a conflict-free RT_ERP_Net is constructed by adding virtual activities. By experiments, it is proved that the resolution strategy proposed can shorten the execution time of the whole process to a great degree.     

Strengthening the Global Financial Safety Net: Challenges and Prospects

The paper shares the idea on the current global financial circumstance; whereas rapid financial globalization was a basic source of the systemic risks of the global financial crisis, the world economy is even more integrated in the aftermath of the global crisis. It emphasizes the importance of the global community to strengthening the GFSN to respond to a crisis. Kim argues that the GFSN should be a multi-layered structure, and only a single layer alone would not be sufficient to handle the global crisis due to its impact of economic damage. More specifically, the paper suggests a multi-layered structure of the GFSN as follows: self-insurance with foreign exchange reserves, bilateral currency swaps by central banks, RFAs already influencing regional financial recourse and stability in several regions, and global arrangements, such as the IMF facilities.     

Coloured Logic Petri Nets and analysis of their reachable trees

Logic Petri nets (LPNs) can describe and analyse the batch processing function and passing value indeterminacy in cooperative systems, and alleviate the state space explosion problem. However, the indeterminate data of logical output transitions cannot be described explicitly in LPNs. Therefore, Coloured Logic Petri nets (CLPNs) are defined in this paper. It can determine the indeterminate data of logic output transitions in LPNs, i.e., the indeterminate data can be represented definitely in CLPNs. A vector matching method is proposed to judge the enabling transitions and analyse CLPNs. From the marking equation and the proposed reachable tree generation algorithm of CLPNs, a reachable tree can be built, and reachable markings are calculated. The advantage of CLPNs can be shown based on the number of leaf nodes of the reachability tree, and CLPNs can solve the indeterminate data of logical output transitions. Finally, an example shows that CLPNs can further reduce the dimensionality of reachable markings.     

基于电缆网时域反射信号检测与预处理技术研究

运行电缆网时域反射信号检测与预处理技术研究。应用小波分析变换电缆网时域反射信号的奇异点进行检测与预处理误差较大,采用小波分析的反射波消噪技术提出一种小波分析最优分解层数的自适应确定函数算法。     

基于Petri网的钢铁企业原料供应物流优化

分析了钢铁企业原料供应物流优化的重要性,利用Petri网建模方法和Arena仿真软件对原料到达入库的物流系统进行了分析并提出了优化措施。     

Central Bank Currency Swaps and the International Monetary System

Central bank currency swaps have emerged as a de facto key feature of the international monetary system, with the US Federal Reserve having extensive recourse to them during the financial crisis, and their exploitation by the People’s Bank of China to help internationalizing the renminbi. Combined with the unlimited and exclusive power of central banks to create money these swaps can match the volatility of international capital flows. However, they have so far not been associated with conditionality, and are more precarious than alternative institutional arrangements. Strictly framing the discretionary use of this tool seems unrealistic but an internationally agreed set of principles would enable a fairer and perhaps more efficient exploitation of this instrument.     

基于Petri网的冷链配送流程仿真优化研究

应用Petri网理论．对冷链配送流程进行优化研究。根据某企业目前的配送流程,利用Petri网理论进行建模。之后运用ExSpect软件对模型进行了仿真。得到仿真结果后,对结果进行分析,并基于效率提高和流程重构两种优化措施对流程进行改进。最后．再次利用软件对改进后的流程进行仿真,说明改进措施的有效性,并增加了随机性仿真,加强仿真结果的可信度。     

基于GSPN的装备器材供应链建模与分析

研究了广义随机Petri网（GSPN）的建模及分析方法,建立了基于GSPN的装备器材供应链流程模型,并将Petri网模型转化为等价的马尔可夫链,得出了供应链模型的主要性能指标,据此分析制约供应链的瓶颈。     

一种高安全性的电子商务解决方案

通过对电子商务解决方案中的关键技术的初步探讨,针对电子商务的安全性问题的解决提出了一种新的解决方案;它可以通过计算机技术和非计算机技术两个方面的手段来增强系统的安全性,这是在电子商务解决方案中的一种有效尝试.该方案具有较强的可操作性,可以推动电子商务技术的发展.