输入串联输出并联全桥变换器强制负载法均压策略

输入串联输出并联全桥变换器在高压大功率DC-DC场合应用十分广泛.本文为了解决输入串联输出并联全桥变换器的输入不均压问题,探究了输入串联输出并联全桥变换器输入侧分压不均和输出侧分流不均的根本原因,研究了该型变换器负载大小对输入均压的影响,定量分析了负载大小和输入不均压程度的关系公式;基于这种分析,提出了通过均压电阻强制给定负载的方法实现输入均压,从而实现了该型变换器的控制简化.文章最后通过仿真和样机实验验证了该方法的有效性和正确性,运用该方法的输入串联输出并联全桥变换器输入电压不均压程度控制在输入电 压的2％,满足工程实践要求.     

基于SSH+Ajax的校园文档资源共享平台设计

针对大学校园文档资源统一管理、交互共享等问题,提出采用SSH框架与Ajax技术,设计交互共享、开放式校园文档资源管理平台。完成平台文档模块接口与类以及平台数据库设计,支持多种格式文档的快速搜索、浏览、上传、下载。实验表明,使用SSH框架可提高文档共享平台的可靠性与复用性,使用Ajax技术提高了资源的共享效率。该平台可有效解决校园文档信息孤岛问题,为高校教学资源的开放共享提供了良好的管理手段。     

离散型合作研发联盟内部收益分配与投资策略研究

研究进行新产品研发时,一个牵头企业与单个合作企业组成的离散型研发联盟内部的利润分配以及投资策略问题。由于研发投入具有较强的时效性,因此,将主要以收益率为决策指标评价投资决策的优劣。通过构建各自的收益率模型,提出两种不同情况下的合作企业U与牵头企业D之间的收益分配和投资策略。一种情况下,两个企业的收益率同时达到最大,而另一种情况下则刚好相反。对于第二种情况提出采用动态利润分配策略来进行系统协调,使U和D的最优策略一致。最后,通过一个算例验证了该模型的有效性。     

Constructions and Properties of General (k,n) Block‐Based Progressive Visual Cryptography

Recently, Hou and others introduced a (2, n) block‐based progressive visual cryptographic scheme (BPVCS) in which image blocks can be gradually recovered step by step. In Hou and others’ (2, n)‐BPVCS, a secret image is subdivided into n non‐overlapping image blocks. When participants stack their shadow images, all the image blocks associated with these t participants will be recovered. However, Hou and others’ scheme is only a simple 2‐out‐of‐n case. In this paper, we discuss a general (k, n)‐BPVCS for any k and n. Our main contribution is to give two constructions (Construction 1 and Construction 2) of this general (k, n)‐BPVCS. Also, we theoretically prove that both constructions satisfy a threshold property and progressive recovery of the proposed (k, n)‐BPVCS. For , Construction 1 is reduced to Hou and others’ (2, n)‐BPVCS.]     

Price‐based interference management in dense femtocell systems

Femtocell technology has been drawing considerable attention as a cost‐effective means of improving cellular coverage and capacity. However, under co‐channel deployment, femtocell system in dense environment may incur high uplink interference to existing macrocells and experiences strong inter‐cell interference at the same time. To manage the uplink interference to macrocell, as well as the inter‐cell interference, this paper proposes a price‐based uplink interference management scheme for dense femtocell systems. Specifically, on the one hand, to guarantee the macrocell users' quality of service, the macrocell base station prices the interference from femtocell users (FUEs) subject to a maximum tolerable interference power constraint. On the other hand, the inter‐cell interference is also taken into consideration. Moreover, a Stackelberg game model is adopted to jointly study the utility maximization of the macrocell base station and FUEs. Then, in order to reduce the amount of information exchange, we design a distributed power allocation algorithm for FUEs. In addition, admission control is adopted to protect the active FUEs' performance. Numerical results show that the price‐based interference management scheme is effective. Meanwhile, it is shown that the distributed power allocation combined with admission control is capable of robustly protecting the performance of all the active FUEs. Copyright © 2013 John Wiley & Sons, Ltd.     

整合实践教学环节的高年级建筑设计教学模式优化探索——以华南理工大学建筑学院为例

本科教学中的实践教学环节及学研产相结合对应用型人才培养至关重要。在建筑学专业高年级实践教学中推行专题设计和"导师制",将实践教学与设计教学相融合,探索"教学、研究、实践"三者相结合的开放式教育模式,有助于实现专业能力拓展的教学目标。     

深圳地铁三号线综合监控系统的特点

简单介绍深圳地铁三号线综合监控项目的内容,综合监控系统的意义,系统中群组监控、后备线控车站、集中维护的管理平台、分布式软件架构、模块化软件设计、联动等多种控制方式和多系统信息共享等特点,并根据项目特点及运营信息化需求,简述综合监控系统的发展趋势。     

博弈的设计:面向土地发展权共享的空间治理

面对空间资源趋向匮乏、产权交易日益频繁的现实情景,土地再开发的制度设计成为新一轮"存量规划"的核心工具。目前,我国的土地发展权存在城乡分割、垄断竞争、公民权利边缘化的问题。土地交易的"市场经济"对应土地分配的"计划经济",导致空间开发陷入既得利益积累的无限循环。针对发展权垄断造成的空间蔓延,政府应设立城市增长边界,剥离地方政府经营土地的职能,强化价值规律对资源的配置作用。同时,进一步明确公共利益的法律定义,加快公众参与的立法赋权。最终,通过土地发展权的共享,实现空间权利的"社会共治"。     

车联网中基于联盟合作博弈的带宽分享策略

近几年来,车联网领域快速发展并引起广泛关注.在此背景下提出了一种混合Wi-Fi、WiMAX和3G/LTE的网络架构,在这种架构下,车辆可以根据自身的情况选择合适的方式接入网络.网络带宽分享采用基于联盟合作博弈的方式,车辆可以选择加入或离开合作联盟来最大化自身收益.模型从理论上证明了通过车辆间的效用分配与博弈合作,最终将形成一个纳什稳定的联盟划分并能适应车辆的动态变化.仿真结果表明,模型的算法性能接近于最优联盟分配.     

Analysis of the risk-sharing ratio in PPP projects based on government minimum revenue guarantees

Public-private partnership (PPP) projects have been widely applied in infrastructure construction. A suitable risk distribution strategy is crucial for promoting negotiations between the government and investors. The government usually provides guarantees to investors to distribute risk. However, an excessive guarantee increases the government's financial burden, whereas an insufficient guarantee reduces the confidence of the investors participating in the project. In a minimum revenue guarantee (MRG), the government subsidizes the investors the difference between the actual revenue and the government guarantee line if there is a loss. In PPP power plant and highway projects, investors' revenues come from two sources: government guarantees and the project company's self-sale. To support project companies and to optimize the projects' benefits, the government should set a reasonable benchmark for purchase amounts. Based on the traditional principal-agent model, this paper introduces the reciprocal preference theory to analyze the risk-sharing ratio most suitable for the government. Then, an optimal incentive mechanism is established to guarantee the project's income. The results indicate that by setting a different guarantee strategy for different participants, the government can utilize reciprocal preference to incentivize investors to exert more effort during a partnership and avoid moral hazard.