城市土地储备制度探究

阐述了城市土地储备制度的含义,研究了城市土地储备制度的发展及土地储备制度在我国出现的必然性,介绍了目前我国城市土地储备制度的类型及优缺点,提出了城市土地储备制度的发展建议,从而真正做到土地市场的与时俱进。     

"预约/随需"充放电服务模式下电动汽车聚合商服务策略

现有充放电服务模式研究中,电动汽车聚合商大多依托用户时移灵活性进行充放电引导,未从用户入网规律性角度考虑。基于此,文章提出“预约/随需”充放电服务模式,以服务预约的方式提前锁定入网规律性用户的充电需求,从而提升电动汽车聚合商的引导效果。首先梳理了“预约/随需”服务业务流程;其次从用户服务角度出发,综合经济影响及便利影响两方面,以最大化用户效用为目标,构建各类用户的最优服务购买策略,分析用户购买意愿;最后从电动汽车聚合商的角度出发,构建基于效用的用户服务选择行为分析模型,帮助其把握不同用户选择的影响,并模拟主从博弈过程进行定价寻优,构建价格引导策略。算例结果表明,相较于现有单一服务模式,“预约/随需”服务模式不仅提升了用户服务质量,而且也节约了电动汽车聚合商的购电成本。     

一种内嵌式永磁同步电机启动策略

针对基于高频电压信号注入法的内嵌式永磁同步电机低速无位置传感器控制系统无法估计转子初始位置导致电机启动运行困难的问题,提出了一种内嵌式永磁同步电机启动策略。该策略通过向d,q轴注入高频脉振三角波电压信号,利用连续信号的解调思想傅里叶分解高频响应电流进行信号调制,获取角度误差信息,采用Luenberger观测器代替单PI调节器构成的锁相环估计转子角度;高频脉振三角波电压信号注入法存在无法进行永磁体N/S极判断问题,该策略采用两次转子预定位法简单有效地将转子定位于位置观测器可准确估计的位置,无需永磁体N/S极判断,控制过程简单易行。Matlab/Simulink仿真结果表明所提出的启动策略稳定有效。     

光互联网体系结构及其关键技术

光互联网络的典型特征是高速宽带、灵活可控、资源高效利用。光突发交换（OBS）结合了光电路交换和光分组交换的优点,又克服了二者的不足,将成为下一代光互联网的一种典型的核心支撑技术。文章分析和讨论了OBS网络增强型通用多协议标记交换（GMPLS）控制面技术、多粒度光交换技术,以及光网络节点结构模型、波长资源预留与调度机制、竞争解决机制、OBS网络故障监测技术等关键技术;还分析和讨论了下一代光互联网络的光虚拟专用网（OVPN）关键技术问题。文章指出为了增强目前光网络在资源分配、服务发现、服务质量保障等方面缺乏与上层IP网络的协同支持,需要对网络控制面体系结构、流量工程和业务管理等方面加强研究。     

Clustering‐based scheduling: A new class of scheduling algorithms for single‐hop lightwave networks

In wavelength division multiplexing (WDM) star networks, the construction of the transmission schedule is a key issue, which essentially affects the network performance. Up to now, classic scheduling techniques consider the nodes' requests in a sequential service order. However, these approaches are static and do not take into account the individual traffic pattern of each node. Owing to this major drawback, they suffer from low performance, especially when operating under asymmetric traffic. In this paper, a new class of scheduling algorithms for WDM star networks, which is based on the use of clustering techniques, is introduced. According to the proposed Clustering‐Based Scheduling Algorithm (CBSA), the network's nodes are organized into clusters, based on the number of their requests per channel. Then, their transmission priority is defined beginning from the nodes belonging to clusters with higher demands and ending to the nodes of clusters with fewer requests. The main objective of the proposed scheme is to minimize the length of the schedule by rearranging the nodes' service order. Furthermore, the proposed CBSA scheme adopts a prediction mechanism to minimize the computational complexity of the scheduling algorithm. Extensive simulation results are presented, which clearly indicate that the proposed approach leads to a significantly higher throughput‐delay performance when compared with conventional scheduling algorithms. We believe that the proposed clustering‐based approach can be the base of a new generation of high‐performance scheduling algorithms for WDM star networks. Copyright © 2008 John Wiley & Sons, Ltd.     

Analysis of blocking probability in optical burst switched networks

In this article, we study the blocking probability in a wavelength division multiplexing (WDM) based asynchronous bufferless optical burst switched (OBS) network, equipped with a bank of wavelength converters. Our analysis encloses two wavelength reservation schemes JIT (just-in-time) and JET (just-enough-time), and two-class data rate. The contribution of our work includes: (i) derivation of an accurate model for blocking probability of lower priority bursts in case of a non-preempted model; (ii) provision of the analytical model for blocking probability calculation in the OBS network, which includes these variables: two signaling schemes, partial wavelength conversion, two-class data, traffic intensity, cross-connect speed, number of wavelengths in WDM fiber, number of fibers in the node, number of wavelength converters, and number of nodes in the path; (iii) simulation results, which show that partial wavelength conversion provide quite satisfactory quality of service. We compare performance in a single OBS node, under various sets of parameter values. The OBS network shows great flexibility in terms of used multiclass data, and there is no dependence on the used higher layer protocol.     

A novel simplified tone reservation combined with cross antenna rotation and inversion to reduce PAPR for MIMO‐OFDM system

In this paper, we first propose a simplified tone reservation (STR) method with low computational complexity which is based on the Fourier series expansion. Then, we analyze how to combine the STR method with the cross antenna rotation and inversion method to reduce the peak‐to‐average power ratio (PAPR) for multi‐input multi‐output orthogonal frequency division multiplexing (MIMO‐OFDM) system. To validate the analytical results, extensive simulations are conducted and the numerical results show the efficiency of the proposed schemes including the PAPR reduction and low computational complexity for MIMO‐OFDM system. Copyright © 2010 John Wiley & Sons, Ltd.     

河流下浅埋深薄基岩煤层部分开采可行性分析

控制覆岩破坏高度是实现水体下安全开采的关键。针对“浅埋深、薄基岩、坚硬顶板”河流下压覆煤炭资源的问题，采用数值模拟的方法，计算了巷柱式和房柱式等部分开采的覆岩破坏高度，并从防水煤岩柱留设、岩梁极限跨度以及煤柱稳定性3个方面论述河流下部分开采的可行性。研究结果表明，部分开采能够很好地控制覆岩破坏高度，煤岩柱厚度基本满足留设防水安全煤岩柱要求；由于上覆基岩柱中存在厚度大于10 m的粗砂岩，在跨度小于8.53 m的情况下可以支撑上覆岩层；设计煤柱安全系数为1.28～1.81，均满足要求。采用采6 m、留6 m的巷柱（窄条带）式开采是最佳方案，面积采出率为50%，按总采出率45%计算，可解放河流压覆区域约52万t煤炭。     

An Efficient Reliability Evaluation Approach for Networks with Simultaneous Multiple‐Node‐Pair Flow Requirements

This paper proposes an efficient approach for reliability evaluation of multiple‐sources and multiple‐destinations flow networks. The proposed approach evaluates multiple node pair capacity related reliability. The proposed approach is a three‐step approach; in the first step, it enumerates network minimal cut sets. These network minimal cut sets are then used to enumerate subset cuts in the second step. Third step involves the evaluation of multiple node pair capacity related reliability from the enumerated subset cuts using a multi‐variable inversion sum‐of‐disjoint set approach. The proposed approach can be used for optimal network design as it combines multiple performance requirements, that is, flow requirements between multiple node pairs and network reliability, in a single criterion. Copyright © 2016 John Wiley & Sons, Ltd.