Event-based optimization of admission control in open queueing networks

In this paper, we use the event-based optimization framework to study the admission control problem in an open Jackson network. The external arriving customers are controlled by an admission controller. The controller makes decision only at the epoch when an event of customer arrival happens. Every customer in the network obtains a fixed reward for each service completion and pays a cost with a fixed rate during its sojourn time (including waiting time and service time). The complete information of the system state is not available for the controller. The controller can observe only the number of total customers in the network. Based on the property of closed form solution of Jackson networks, we prove that the system performance is monotonic with respect to the admission probabilities and the optimal control policy has a threshold form. That is, when the number of total customers is smaller than a threshold, all of the arriving customers are admitted; otherwise, all are rejected. The sufficient condition and necessary condition of optimal policy are also derived. Furthermore, we develop an iterative algorithm to find the optimal policy. The algorithm can be executed based on a single sample path, which makes the algorithm online implementable. Simulation experiments are conducted to demonstrate the effectiveness of our approach.     

半刚性钢-混凝土组合节点受弯承载力的计算

在半刚性钢 -混凝土组合框架中 ,混凝土板中的纵向钢筋增加了节点的强度和刚度 ,但是 ,传统的设计方法往往忽略纵向钢筋的作用而采用简化的计算模型。因此 ,出于经济效益考虑 ,应该根据半刚性组合节点的实际受力性能建立更加准确的计算方法。这里详细介绍了考虑混凝土板纵向钢筋作用的半刚性组合节点受弯承载力的计算方法 ,计算结果表明 ,建议的公式与试验结果吻合良好 ,可供规范制定和工程应用参考。     

动态格点搜索的改进算法用于团簇结构快速优化

结合高效的动态格点搜索(DLS)算法与扰动操作(Perturbation Operation)提出一种新的改进方法(DLS-PO),用于确定团簇的最低能量结构。针对一个特定构型,DLS算法总能给出其对应搜索空间的最规则结构。然而,一次失败的DLS优化将消耗大量的运算资源。为此,采取原子移动和结构旋转的扰动操作成功地改变了构型,再结合后续的DLS操作,提高了优化效率。将该算法用于原子数高达309的Lennard-Jones团簇及100原子NP-B函数铝团簇的结构优化。优化结果显示相比于DLS算法,DLS-PO算法更为高效。     

基于改进符号化度量方法的机场噪声异常检测

机场噪声中的异常情况拥有很大价值,利用它能够及时完善飞机和机场的设备。结合机场噪声数据的特点,对上述问题进行研究并提出一种基于改进的符号化聚集近似(Symbolic Aggregate Approximation,SAX)相似性度量的单监测点的时间序列异常检测方法。其运用相似性度量方法计算出度量结果,再运用k近邻异常检测方法进行异常发现,最后发现异常时间段。该方法在理论验证可行性之后在某机场的实测数据中进行应用,取得了良好的效果。     

深圳市大康河综合整治工程生态化治理研究

以大康河综合整治工程为背景对河道生态化整治进行研究,对工程涉及的防洪、水质、景观等基本现状进行评价,提出了生态治理的指导思想,并具体介绍了防洪、水质、景观等综合治理措施,通过对大康河的综合整治,使得工程既能满足防洪要求又能实现良好的生态景观效果。     

Making sky lanterns from polygonal meshes

Releasing sky lanterns is a popular way of celebrating festivals and ceremonies in the Asian countries. This paper presents a computer-aided approach to help novice users to design flyable sky lantern with desired shape. Given a closed up-right 3D model with a user-specified cutting on the bottom, our system optimizes the shape by regularizing the boundary, smoothing the geometry and improving the volume-to-area ratio to make it feasible for flying. The optimized shape is then approximated by a set of developable patches. Next, through a physical analysis step that tests the flying condition and determines the optimal size, the approximated shape is flattened into 2D patches, which can be printed out and glued together to form the airbag. Finally, the user can attach the airbag to a bamboo frame and assemble the fuel cell. We successfully apply our prototype system to design and construct real sky lanterns.     

An FAR-SW based approach for webpage information extraction

Automatically identifying and extracting the target information of a webpage, especially main text, is a critical task in many web content analysis applications, such as information retrieval and automated screen reading. However, compared with typical plain texts, the structures of information on the web are extremely complex and have no single fixed template or layout. On the other hand, the amount of presentation elements on web pages, such as dynamic navigational menus, flashing logos, and a multitude of ad blocks, has increased rapidly in the past decade. In this paper, we have proposed a statistics-based approach that integrates the concept of fuzzy association rules (FAR) with that of sliding window (SW) to efficiently extract the main text content from web pages. Our approach involves two separate stages. In Stage 1, the original HTML source is pre-processed and features are extracted for every line of text; then, a supervised learning is performed to detect fuzzy association rules in training web pages. In Stage 2, necessary HTML source preprocessing and text line feature extraction are conducted the same way as that of Stage 1, after which each text line is tested whether it belongs to the main text by extracted fuzzy association rules. Next, a sliding window is applied to segment the web page into several potential topical blocks. Finally, a simple selection algorithm is utilized to select those important blocks that are then united as the detected topical region (main texts). Experimental results on real world data show that the efficiency and accuracy of our approach are better than existing Document Object Model (DOM)-based and Vision-based approaches.     

用顶空-气相色谱法检测水中一氯苯

介绍了使用顶空-气相色谱法检测水中一氯苯的方法。该方法使氯苯分子在气液两相之间、在一定温度下达到了动态平衡。此时,一氯苯在气相中的浓度与它在液相中的浓度成正比。通过测定气相中一氯苯的浓度,即可计算出水样中氯苯的浓度。使用该方法可以直接测定水样,与国标方法相比,它无需琐碎的前处理过程,避免了实验人员与有毒有害溶剂的接触,而且测定结果稳定性较好,能够满足测定需求。     

毕业生MIS系统在高职院校的研究与应用

毕业生信息管理在高校的日常管理工作中是核心工作,自动化信息化管理会给学校的日常管理工作带来很大的方便。基于江苏海事职业技术学院的实际需求,本文设计开发了毕业生信息管理系统。本系统主要分为四个部分:网站门户、就业信息管理、资料管理和毕业论文管理。系统开发采用JSP技术,使用开源My SQL数据库,系统部署在开源Web服务器Tomcat上,操作系统是Linux系统。