冗余机器人的双向自运动路径规划

冗余机器人的自运动路径规划是在保持手端任务向量不变的情况下,在关节空间内寻找一条连接机器人初始关节构形和期望关节构型的几何路径.本文给出一种双向自运动路径规划算法,其基本思想是使位于初始关节构形的真实机器人和位于期望关节构形的虚拟机器人在自运动流形上运动并收敛到同一关节构形,从而得到一条连接初始和期望关节构形的自运动几何路径.该算法克服了以往算法容易陷入局部极小构形的缺陷.仿真结果证实了算法的有效性.     

Network protection codes: Providing self-healing in autonomic networks using network coding

Agile recovery from link failures in autonomic communication networks is essential to increase robustness, accessibility, and reliability of data transmission. However, this must be done with the least amount of protection resources, while using simple management plane functionalities. Recently, network coding has been proposed as a solution to provide agile and cost efficient self-healing against link failures, in a manner that does not require data rerouting, packet retransmission, or failure localization, hence leading to simple control and management planes. To achieve this, separate paths have to be provisioned to carry encoded packets, hence requiring either the addition of extra links, or reserving some of the resources for this purpose.In this paper we introduce self-healing strategies for autonomic networks in order to protect against link failures. The strategies are based on network coding and reduced capacity, which is a technique that we call network protection codes (NPC). In these strategies, an autonomic network is able to provide self-healing from various network failures affecting network operation. Also, network protection codes are extended to provide self-healing from multiple link failures in autonomic networks. Although this leads to reducing the network capacity, the network capacity reduction is asymptotically small in most cases of practical interest. We provide implementation aspects of the proposed strategies, derive bounds and show how to construct network protection code. The paper also develops an Integer Linear Program formulation to evaluate the cost of provisioning connections using the proposed strategies, and uses results from this formulation to show that it is more resource efficient than 1 + 1 protection. A simulation study to evaluate the recovery times, and the buffering requirements due to network coding is also conducted using the OPNET simulator.     

Simple token ring local area network

The implementation of a simple token ring system is described. A token ring is a form of local area network in which hosts must capture the token, a unique bit pattern, to use the communications medium. Many existing token ring implementations designate a separate host as a monitor station for the ring. Thus ring initialization and recovery are centralized, so it the monitor is down the ring becomes unusable.Our aim was to build a simple cheap token ring which would have advantages over an Ethernet-style local area network in terms of guaranteed access time upper bounds. We also attempted to decentralize initialization and recovery by giving each host the ability to initialize and repair the ring.     

Topological network design for SONET ring architecture

Service restoration and survivability have become increasingly important in telecommunications network planning with the introduction of fiber-optic high-speed networks. Synchronous optical network (SONET) technology promotes the use of interconnected rings in designing reliable networks. We describe a heuristic approach for designing networks comprised of interconnected rings. Our approach is particularly attractive for relatively sparse networks in which the set of all cycles (constituting the potential rings) can be determined at a reasonable computational effort. Most networks fall into this category. Given a set of nodes, with demand among all possible node-pairs, and a set of available links that connect the nodes, the problem is to select an optimal subset of rings, utilizing only allowable links, such that each node is included in at least one ring and each ring is connected to at least one other ring at two or more nodes. Such a multiple ring network ensures instantaneous restoration of service in case of a single link or node failure. We first generate a large set of candidate rings and approximate the cost of each ring based on the nodes that are served by the ring and based on the demands. We then apply a set covering algorithm that selects a (minimum cost) subset of the candidate rings such that each node is included on at least one ring. Finally, we select a few additional rings in order to achieve the required connectivity among the rings. We present computational results for realistic-size (e.g., 500 nodes) telecommunication networks     

Queuing network decomposition and facilities planning

We have shown previously that open, closed, and mixed networks of queues are viable means of analyzing the configuration and composition of resources in facility layout problems. In this paper, we explore the scope and limitations of decomposition techniques for modelling general arrival and service processes M/G/C, M/D/C and GI/G/C within facilities. The robustness of our analytical approach is then compared with a simulation analysis of an example facility.     

The electrical distribution network planning problem

In this paper we are dealing with the electrical distribution network planning problem where a network configuration has to be specified in order to meet demand, to satisfy the operating constraints, and to minimize investment, operating, and power–loss costs. The iterative procedure includes several heuristic algorithms to generate a radial network, to choose a set of open feeders to meet the reliability constraint, and to solve the reconfiguration problem in order to reduce the power–loss costs. Furthermore, in order to compare the reliability of potential solutions, a predictive reliability assessment measure is established.     

多跳环形量子网络密钥共享协议的研究

为有效解决量子网络的安全问题,提出了多跳环形量子网络的量子密钥共享协议.该协议在由2N+1个量子节点组成的环形网络中通过EPR对传输密钥.量子节点t0利用CONT门、H门操作,将密钥通过t1传递给t2,再多跳的依次传递给量子节点t4,…,t2通过t3…t2N-1,最终将共享信息传递给最后的量子节点.该协议利用现有的手段可以实现.     

光纤环网中建立数据传输模型的方法研究*

为了在光线环网中高效地传输数据,首先确定了所研究光纤环网的物理拓扑结构,是一种多信道单向环网,然后详细地阐述了在其中建立数据传输模型的步骤和方法,以及各个模块的流程图,最后在设计的实验平台上对模型进行了完整的测试,测试结果表明数据传输模型可以在光纤环网中高效且正确地运行。     

5G无线智能网络规划方案研究

5G移动通信引入大规模阵列天线、新场景、新业务、新频段等关键技术,未来网络演进的目标是通过人工智能的引入实现网络的自主决策和自主演进,5G网络规划也面临智能化演进的需求。从5G网络规划部署各个阶段探讨了从工作流程、规划方案等方面,如何在大数据基础上,结合机器学习等技术,基于价值建网,形成整体5G网络规划方案,应用于指导5G网规规划建设。     

Corrective action planning using RBF neural network

In recent years, voltage limit violation and power system load-generation imbalance, i.e., line loading limit violation have been responsible for several incidents of major network collapses leading to partial or even complete blackouts. Alleviation of line overloads is the suitable corrective action in this regard. The control action strategies to limit the line loading to the security limits are generation rescheduling/load shedding. In this paper, an approach based on radial basis function neural network (RBFN) is presented for corrective action planning to alleviate line overloading in an efficient manner. Effectiveness of the proposed method is demonstrated for overloading alleviation under different loading/contingency conditions in 6-bus system and 24-bus RTS system.     

Multicriteria distribution network planning using simulated annealing

The classical long-range distribution network planning problem involves deciding network investments to meet future demand at a minimum cost while meeting technical restrictions (thermal limits and maximum voltage drop). The decision whether to construct facilities and branches leads to a mixed integer programming problem with a large number of decision variables. The great deal of uncertainty associated with data that cannot be modeled using probabilistic methods leads to the use of fuzzy models to capture the uncertainty. In addition, several criteria must be taken into account that is resulting in the problem being fuzzy multiobjective. The combinatorial nature of the problem limits the use of traditional mathematical tools to limited size problems. This contribution presents a methodology that generates a sample of efficient solutions for the fuzzy multiobjective problem, based on a meta-heuristic, simulated annealing (SA). The results obtained with this approach are shown to be satisfactory compared to other methods under similar conditions.     

Robust network planning in nonuniform traffic scenarios

Robustness to the environmental variations is an important feature of any reliable communication network. This paper reports on a network theory approach to the design of such networks where the environmental changes are traffic fluctuations, topology modifications, and changes in the source of external traffic. Motivated by the definition of betweenness centrality in network science, we introduce the notion of traffic-aware betweenness (TAB) for data networks, where usually an explicit (or implicit) traffic matrix governs the distribution of external traffic into the network. We use the average normalized traffic-aware betweenness, which is referred to as traffic-aware network criticality (TANC), as our main metric to quantify the robustness of a network. We show that TANC is directly related to some important network performance metrics, such as average network utilization and average network cost. We prove that TANC is a linear function of end-to-end effective resistances of the graph. As a result, TANC is a convex function of link weights and can be minimized using convex optimization techniques. We use semi-definite programming method to study the properties of the optimization problem and derive useful results to be employed for robust network planning purposes.     

论信息系统网络改造规划

中国电子口岸数据中心建设十余年来,随着业务不断增长,已经发展成为以口岸通关管理向物流商务延伸的统一网络信息平台。作为直属关的xx分中心,急需对现有的网络进行安全等相关方面扩容和改造及相关项目的跨平台对接,实现业务延伸。     

利用增强烟花算法对RFID网络进行规划

为了实现面向复杂环境下的RFID（Radio Frequency Identification）网络规划,提出利用增强烟花算法,并采用分层方法来实现多目标RFID网络的规划。通过建立优化模型,在满足标签100%覆盖率、部署更少的阅读器、使用较少的发射功率和避免信号干扰四个目标的基础上,使用标准基测试集进行测试,与GPSO（Global topology Particle Swarm Optimization）、VNPSO（Von Neumann topology Particle Swarm Optimization）、GPSO-RNP（Global topology Particle Swarm Optimization-RFID Network Planning）和VNPSO-RNP（Von Neumann topology Particle Swarm Optimization-RFID Network Planning）四种算法进行了对比分析。实验结果表明,增强烟花算法在对多目标RFID进行网络规划时表现更优异,可以更有效地求出最优化方案。     

Multistage ring network: An interconnection network for large scale shared memory multiprocessors

Unidirectional ring-based networks are currently popular choices for high performance large scale shared memory multiprocessors. This class of networks is attractive for their simple hardware interfaces, high speed communication, wider data path, and easy addition of extra nodes. However, a single ring does not scale well due to the fixed bandwidth, and the hierarchical ring networks as a natural extension of a single ring show limited scalability due to their limited bandwidth near the root. In this paper we present a new interconnection network called the Multistage Ring Network (MRN). The MRN has a 2-level hierarchy of rings, and its interconnection of global rings forms a type of the multistage network. The architecture of the MRN is effective at diffusing the global traffic on the network to all global rings, and the bandwidth of the network increases proportionally with increases in the system size. Our results show that in a peak throughput, the MRN performs seven times better than the hierarchical ring network for system size of 1024.     

基于虚拟位置的无线传感器网络环路由协议

无线传感器网络中节点的能源和处理能力受限,难以提供大规模的、以数据为中心的服务。为了解决以上问题,提出了一个基于虚拟位置的环路由协议。此协议使用分布式哈希表管理数据。虚拟位置概念的引入减少了冗余的路由信息并优化了路由的路径,从而减轻了节点的负担并提升了数据传送的效率。根据仿真结果以及与相关协议的对比,证明了此协议的有效性和可扩展性。     

Toward self-healing infrastructure systems

A joint industry-government initiative is developing a mathematical basis and practical tools for improving the security, performance, reliability and robustness of energy, financial, telecommunications and transportation networks. The first challenges are to develop appropriate models for this degree of complexity and to create tools that let components adaptively reconfigure the network as needed     

Hierarchical task network and operator-based planning: two complementary approaches to real-world planning

Work on generative planning systems has focused on two diverse approaches to plan construction. Hierarchical task network (HTN) planners build plans by successively refining high-level goals into lower-level activities. Operator-based planners employ means-end analysis to directly formulate plans consisting of low-level activities. While many have argued the universal dominance of a single approach, this paper presents an alternative view: that in different situations either may be most appropriate. To support this view, a number of advantages and disadvantages of these approaches are described in light of experiences in developing two real-world, fielded planning systems.