Sewage flow optimization algorithm for large-scale urban sewer networks based on network community division

By considering the flow control of urban sewer networks to minimize the electricity consumption of pumping stations, a decomposition-coordination strategy for energy savings based on network community division is developed in this paper. A mathematical model characterizing the steady-state flow of urban sewer networks is first constructed, consisting of a set of algebraic equations with the structure transportation capacities captured as constraints. Since the sewer networks have no apparent natural hierarchical structure in general, it is very difficult to identify the clustered groups. A fast network division approach through calculating the betweenness of each edge is successfully applied to identify the groups and a sewer network with arbitrary configuration could be then decomposed into subnetworks. By integrating the coupling constraints of the subnetworks, the original problem is separated into N optimization subproblems in accordance with the network decomposition. Each subproblem is solved locally and the solutions to the subproblems are coordinated to form an appropriate global solution. Finally, an application to a specified large-scale sewer network is also investigated to demonstrate the validity of the proposed algorithm.

Multi-Core Virtual Concatenation Scheme Considering Inter-Core Crosstalk in Spatial Division Multiplexing Enabled Elastic Optical Networks

Spatial division multiplexing enabled elastic optical networks(SDM-EONs) are the potential implementation form of future optical transport networks, because it can curve the physical limitation of achievable transmission capacity in single-mode fiber and single-core fiber. However, spectrum fragmentation issue becomes more serious in SDM-EONs compared with simple elastic optical networks(EONs) with single mode fiber or single core fiber. In this paper, multicore virtual concatenation(MCVC) scheme is first proposed considering inter-core crosstalk to solve the spectrum fragmentation issue in SDM-EONs. Simulation results show that the proposed MCVC scheme can achieve better performance compared with the baseline scheme, i.e., single-core virtual concatenation(SCVC) scheme, in terms of blocking probability and spectrum utilization.

Real-Time Upstream Services Demonstration in Orthogonal Frequency Division Multiplexing- Passive Optical Network System

Abstract： Real-time digital service and mul- timedia service upstream transmission in Dig- ital Signal Processing （DSP）-based Orthogo- nal Frequency Division Multiplexing-Passive Optical Network （OFDM-PON） is experimen- tally demonstrated with Centralised Light Sou- rce （CLS） configuration in this paper. After transmitted over 25 km Standard Single Mode Fibre （SSMF） with -16.5 dBm optical power at receiver, the Bit Error Rate （BER） is 9.5 ×10^-11. The implementations of digital domain up-conversion and down-conversion based on Field Programmable Gate Array （FPGA） are int- roduced, which can reduce the cost of In-ph- ase and Quadrature （IQ） radio frequency mix- ers utilised at transmitter and receiver. A car- rier synchronization algorithm is implemented for compensating carrier offset. A channel eq- ualization algorithm is adopted for compen- sating the damage of channel. A new structure of Frequency Synchronization Unit （FSU） des- igned in FPGA is also proposed to cope with the frequency shifting at receiver.

Modeling and Dynamic Analysis in Software Systems Based on Complex Networks

A software network model with multiple links is constructed on the basis of a dynamical model of a general complex network with mukiple links. The principle of network division of multiple links is introduced. Following these principles, the software network model is decomposed into three types of subnets and different relationships between classes are revealed. Then, the dynamic analysis of software networks is presented. A sufficient condition for the stability of general complex networks is obtained followed by that of software networks. Finally, the dynamics of an open-source software system is analyzed, and their simulations are provided to demonstrate the effectiveness of the presented model.

Equilibrium Analysis for Anycast in WDM Networks

In this paper, the wavelength-routed WDM network was analyzed for the dynamic case where the arrival of anycast requests was modeled by a state-dependent Poisson process. The equilibrium analysis was also given with the UWNC algorithm.

ROUTING AND WAVELENGTH ASSIGNMENT ALGORITHMS BASED ON EQUIVALENT NETWORKS

In this paper, a Wavelength Division Multiplexing (WDM) network model based on the equivalent networks is described, and wavelength-dependent equivalent arc, equivalent networks, equivalent multicast tree and some other terms are presented. Based on this model and relevant Routing and Wavelength Assign- ment (RWA) strategy, a unicast RWA algorithm and a multicast RWA algorithm are presented. The wave- length-dependent equivalent arc expresses the schedule of local RWA and the equivalent network expresses the whole topology of WDM optical networks, so the two algorithms are of the flexibility in RWA and the optimi- zation of the whole problem. The theoretic analysis and simulation results show the two algorithms are of the stronger capability and the lower complexity than the other existing algorithms for RWA problem, and the complexity of the two algorithms are only related to the scale of the equivalent networks. Finally, we prove the two algorithms’ feasibility and the one-by-one corresponding relation between the equivalent multicast tree and original multicast tree, and point out the superiorities and drawbacks of the two algorithms respectively.

Robust Design of Virtual Topology for WDM Networks under Bandwidth Demand Uncertainties

In this paper, a novel method is proposed to address the problem of designing virtual topology over wavelength division multiplexing （WDM） networks under bandwidth demand uncertainties. And a bandwidth demand model under uncertainties is presented. The optimization goal of virtual topology design is defined as minimizing the maximum value amongp percentiles of the bandwidth demand distribution on all Hght-paths. Correspondingly, we propose a heuristic algorithm called an improved decreasing multi-hop logical topology design algorithm （ID-MLTDA） that involves with a degree of uncertainties to design virtual topology. The proposed algorithm yields better performance than previous algorithms. Additionally, the simplicity and efficiency of the proposed algorithm can be in favor of the feasibility for topology design of large networks.

神经网络相平面分区控制器研究与仿真

将神经网络的在线学习、即时调节功能与相平面分区的逻辑判断特性相结合提出了一种新的智能控制器———神经网络相平面分区控制器.该控制器将系统响应的基本性能与相应工况的控制作用力的划分和作用强度在相平面上建立起了实时的相互对应关系,从而使各分区内的控制参数能随着被控对象的变化在线自动调节参数,具有自适应能力.仿真结果表明,利用该方法设计的控制器闭环性能好、鲁棒性强.该方法为非线性控制提供了一种有效的控制器设计途径.

网络结构视角下的中国电力系统生产效率研究

电力系统在国家能源安全战略中占据重要地位,综合评估电力系统及其发电、输电、配电子部门生产效率对于社会经济高质量发展具有重要意义。采用网络数据包络分析方法(data envelopment analysis,DEA)模型对2014—2017年间中国电力系统生产效率进行分析。相比于传统DEA模型,网络DEA模型可通过上网电量、配电量等连接变量对系统内部联系进行建模并探索系统效率低下的内部因素。研究表明:中国电力系统生产效率区域差异性明显,新一轮电力体制改革对于电力系统的发展具有促进作用。外界环境的异质性导致区域电力系统各部门发展情况不同,生产绩效的提升应根据区域实际情况有所侧重。

农村中压配电网供电模型研究

目前,国内对农村网架结构的研究主要集中在接线模式,不能体现农村不同区域属性条件下变电站的供电结构问题。借鉴国内外城市配电网典型供电模型的设计经验,提出了农村中压配电网典型供电模型的构建方法。在对农网供电模型进行定义并分析其构建影响因素的基础上,采用分区加权Voronoi图对农网供电区域进行划分,实现农网的分区供电;采用最小生成树(MST)生成农村中压配电网的供电架构和结合接线模式,构建适合农村地区的、系列化、差异化供电模型。通过对农网供电模型扩展的进一步研究,为农村电网建设与配电网改造提供支撑。

直流调速系统神经模糊自适应控制器设计

针对传统PID控制的不足,将传统PID控制和神经网络控制有效结合,构成神经模糊自适应控制器,作为双闭环直流调速系统的转速调节器,电流调节器仍采用PID控制。同时采用分目标误差学习规则对神经网络进行训练,使系统过渡过程平稳,稳态无静差。仿真结果表明,转速调节器改进后系统的超调量明显减小,调节时间变短,动态特性和抗干扰性均有所提高。

城市轨道交通中压环网大分区供电保护方案比选

介绍了城市轨道交通中压环网供电保护的各种方案,包含过流时间级差方案、硬线闭锁方案、近区速动方案、动态加速方案、GOOSE(面向通用对象的变电站事件)网络方案、电流选跳方案及线路母线全差动方案等。对比分析了各方案的可靠性、选择性、经济性和复杂性等性能。其比较结果可为城市轨道交通后续工程供电保护方案选择提供参考。

多井口分区式通风网络简化技术研究及实践

晋华宫矿在生产中,形成河北、河南两大生产区域共“十进四回”的通风方式。日常生产中,虽然整体通风系统稳定、十个进风井均有服务区域,但由于风井数量较多,仅在风井管理上就投入大量的精力。且井田内可采储量逐步萎缩,可进行采、掘活动的煤层逐渐减少。少数煤层已多年处于残采供风状态,不仅占用了风量资源,而且需投入大量的人力、物力去进行日常管理和系统维护。为此,开展此项研究,旨在通过梳理矿井现状,分析相关区域尤其是残采盘区优化收缩及进风井口简化的可行性,并研究制定具体的实施方案。

城市供水管网分区供水技术分析

管网分区供水能够提升供水产销差率、控制管网漏损、提升水损失计量精度,是城市供水从粗放式向精细化转型的重要手段。文章对城市供水管网分区供水技术进行分析,阐述管网分区供水方案设计流程及分区规则,说明建立管网水力模型和MATLAB最短路径计算的方法,并以江苏省苏州市工业园区某处管网实际数据为基础,验证该方法的有效性。

Optical SDMA for applying compressive sensing in WSN

In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space division multiple access, and a sensor node uses a modulating retro-reflector for communication. Thus while a random sampling matrix is used to guide the establishment of links between head cluster and sensor nodes, the random linear projection is accomplished. To establish multiple links at the same time, an optical space division multiple access antenna is designed. It works in fixed beams switching mode and consists of optic lens with a large field of view（FOV）, fiber array on the focal plane which is used to realize virtual channels segmentation, direction of arrival sensor, optical matrix switch and controller. Based on the angles of nodes＇ laser beams, by dynamically changing the route, optical matrix switch actualizes the multi-beam full duplex tracking receiving and transmission. Due to the structure of fiber array, there will be several fade zones both in the focal plane and in lens＇ FOV. In order to lower the impact of fade zones and harmonize multibeam, a fiber array adjustment is designed. By theoretical, simulated and experimental study, the antenna＇s qualitative feasibility is validated.

A cost-effective structure of a centralized-light-source WDM-PON utilizing inverse-duobinary-RZ downstream and DPSK upstream

In this paper, we propose a new structure of a centralized-light-source wavelength division multiplexed passive op- tical network （WDM-PON） utilizing inverse-duobinary-return-to-zero （inverse-duobinary-RZ） downstream and DPSK up- stream. It reuses downstream light for the upstream modulation, which retrenches lasers assembled at each optical network unit （ONU）, and ultimately cuts down the cost of ONUs a great deal. Meanwhile, a 50-km-reach WDM-PON experiment with 10-Gb/s inverse-duobinary-RZ downstream and 6-Gb/s DPSK upstream is demonstrated here. It is revealed to be a novel cost-effective alternative for the next generation access network.

2 Tbit/s based coherent wavelength division multiplexing passive optical network for 5G transport

Future high-speed mobile communication systems require low latency and high capacity networks.Coherent wavelength division multiplexing(WDM)passive optical network(PON)scheme is expected to play a vital role in these systems.In this paper,coherent WDM-PON scheme based on dual-polarization 16-quadrature amplitude modulation(DP-16 QAM)transceiver has been investigated.The aim of this scheme is to build a 2 Tbit/s(125 Gbit/s/λ×16 wavelengths)network that will be used in the construction of the transport architecture of fifth generation(5 G)and beyond 5 G(B5 G)cellular networks either in mobile front haul(MFH)or mobile back haul(MBH).The results indicate that the proposed scheme is very adequate for both 5 G and B5 G cellular networks requirements.

Shared-p-cycles method for design of survivable WDM networks

In future high-capacity wavelength division multiplexed(WDM)optical networks,the failure of a network component such as a fiber link can lead to severe disruption in the networks’traffic.Hence,it is imperatively important to provide fast and full protection in WDM optical networks.In this paper,we propose a new approach,called shared preconfigured protection cycles(shared-p-cycles),for the design of survivable WDM networks.We develop an integer linear program(ILP)formulation to solve the problem of shared-p-cycles design for WDM networks with and without wavelength conversion.Numerical results show that the shared-p-cycles design is more efficient in the use of spare capacity and requires much less spare capacity than the conventional pcycles design.

矩阵型网络DEA模型及其实证检验

针对传统DEA模型无法有效的评价矩阵型网络系统的效率,本文构建了矩阵型网络决策单元的生产可能集,建立了矩阵型网络DEA模型。在此基础上证明了决策单元在矩阵型网络DEA模型下为弱DEA有效的充分必要条件为其每个子系统均为弱DEA有效。最后,选用美国的十个电力公司作为决策单元对模型进行实证检验,得出结论:矩阵型网络DEA模型弥补了传统DEA模型无法反映内部有效性从而可能得到错误结果的缺陷,并能精确地计算出各个子过程的效率,辨识出具体需要改进的子过程。同时新模型为评价复杂系统的效率提供了新的思路。