Compressionless routing: a framework for adaptive andfault-tolerant routing

Compressionless routing (CR) is an adaptive routing framework which provides a unified framework for efficient deadlock free adaptive routing and fault tolerance. CR exploits the tight coupling between wormhole routers for flow control to detect and recover from potential deadlock situations. Fault tolerant compressionless routing (FCR) extends CR to support end to end fault tolerant delivery. Detailed routing algorithms, implementation complexity, and performance simulation results for CR and FCR are presented. These results show that the hardware for CR and FCR networks is modest. Further, CR and FCR networks can achieve superior performance to alternatives such as dimension order routing. Compressionless routing has several key advantages: deadlock free adaptive routing in toroidal networks with no virtual channels, simple router designs, order preserving message transmission, applicability to a wide variety of network topologies, and elimination of the need for buffer allocation messages. Fault tolerant compressionless routing has several additional advantages: data integrity in the presence of transient faults (nonstop fault tolerance), permanent fault tolerance, and elimination of the need for software buffering and retry for reliability. The advantages of CR and FCR not only simplify hardware support for adaptive routing and fault tolerance, they also can simplify software communication layers     

基于节点偏序关系的路由可用性框架研究

为了维护路由可用性,需要采取一定的路由保护策略来防止网络故障可能对网络造成的影响。因此,提出了一种基于节点偏序关系的路由可用性框架,该框架首先利用节点之间的偏序关系构造有向无环图,然后根据构造的有向无环图为每个节点计算备份下一跳节点。在此框架基础上,根据节点之间的偏序关系提出了四种路由保护方法。实验结果表明,四种路由保护算法都拥有较高的故障保护率,能有效降低故障造成的网络中断,在真实拓扑中故障保护率可以到达89.76%,在模拟拓扑中故障保护率达到98.995%,几乎接近100%。     

New routing framework base on rumor routing in wireless sensor networks

Rumor routing is a classic routing algorithm based on agents’ random walk. This paper proposes a novel approach based on this routing algorithm. Here, we try to improve the latency and energy consumption of the traditional algorithm using propagation of query and event agents within straight lines, instead of using purely random walk paths. As can be seen in our results, this method improves the delivery ratio of the queries which is a drawback of traditional rumor routing. Due to the reduction of final path length between source and destination, we introduce a second layer geographical routing. Moreover, a method is proposed to reduce the cost of localization equipments by using cheaper equipments like AoA antennas. In order to compare the performance measures with traditional algorithm, a simulation framework is developed and extensive simulations are performed.     

H.323网守在呼叫路由中的应用研究

以H．323网守在VoIP体系结构中的作用和地位为基础,重点阐述了H．323网守在呼叫路由中的应用;通过实际的项目开发经验和理论研究成果,提出了一种分布式网守拓扑结构中域内和域间呼叫路由的解决方案,使用这种网守拓扑结构作为对分级网守结构中网络拓展的一种补充,从而加速了H．323网守在VoIP体系中进行注册节点地址解析和呼叫路由的进程。目前,这种方法在VANLINK公司H．323网守中已经得到证实。     

ZigBee协议改进和在医用呼叫系统中的应用

针对目前ZigBee协议中所采用的按需平面距离矢量(AODV)路由协议在节能性和安全性方面存在的局限和不足的问题,提出了采用发射功率可调技术和捎带确认技术对此作出两方面改进,并且通过仿真验证其可实现性。同时,将改进后的ZigBee协议栈应用到医用呼叫系统中。作为医用呼叫系统,该系统在完成呼叫系统的功能同时,添加了医用输液监控的功能。系统使用CC2450芯片为核心的射频模块完成无线数据传输,采用ARM Cortex-M3内核的STM32系列处理器作为系统的主控芯片,保证系统的功能的实现。实验结果表明,该系统安装方便,使用简单,价格低廉,功耗更低,可广泛应用于酒店、银行、餐厅、娱乐场所等其他服务性行业中,具有广阔的市场前景。     

Computational-mechanism design: a call to arms

Computational-mechanism design has an important role to play in developing complex distributed systems comprising multiple interacting agents. Game theory has developed powerful tools for analyzing, predicting, and controlling the behavior of self-interested agents and decision making in systems with multiple autonomous actors. These tools, when tailored to computational settings, provide a foundation for building multiagent software systems. This tailoring gives rise to the field of computational-mechanism design, which applies economic principles to computer systems design.     

Uncertainty analysis framework for trust based routing in MANET

MANET (Mobile Ad hoc Network) has distinctive characteristics like node mobility, broadcast nature of wireless communication, and peer to peer data transfer. Due to these characteristics uncertainty is an integral part of MANET behavior. Uncertainty quantification is important for performance evaluation and better decision making in MANET. Packet dropping is a serious issue in MANET which degrades the performance of the network to a great extent. The packet dropping attack increases uncertainty in the network communication and eventually of the MANET. Trust based routing mechanisms are useful for neutralizing packet dropping attack. There are many existing trust based routing protocols which uses uncertainty for precise trust calculations. Thus, trust and uncertainty are closely related to each other. The paper proposes Uncertainty Analysis Framework (UAF) for MANET, it calculates the network Belief, Disbelief, and Uncertainty (BDU) values. The UAF framework integrated into different trust variants of AODV protocol which use direct trust, indirect trust, and global trust. The research work discovers impact of different trust models on MANET BDU using various mobility models. Experimental analysis shows that, trust based routing protocols show average 3 % gain in packet delivery ratio and at least 5 % increase in the network belief.     

基于RF5框架的XDAIS标准算法封装与调用

介绍了TI DSP算法标准XDAIS(TMS320 algorithm standard)和算法参考框架RF5(Reference Framework 5),分析了XDAIS算法接口的实现和RF5框架中数据元素的操作流程。通过建立标准算法库,并在实例工程中基于RF5框架实现标准算法的封装与调用,较大地提高了算法性能。     

A general framework for efficient geographic routing in wireless networks

We propose a new link metric called normalized advance (NADV) for geographic routing in multihop wireless networks. NADV selects neighbors with the optimal trade-off between proximity and link cost. Coupled with the local next hop decision in geographic routing, NADV enables an adaptive and efficient cost-aware routing strategy. Depending on the objective or message priority, applications can use the NADV framework to minimize various types of link cost.We present efficient methods for link cost estimation and perform detailed experiments in simulated environments. Our results show that NADV outperforms current schemes in many aspects: for example, in high noise environments with frequent packet losses, the use of NADV leads to 81% higher delivery ratio. When compared to centralized routing under certain settings, geographic routing using NADV finds paths whose cost is close to the optimum. We also conducted experiments in Emulab testbed and the results demonstrate that our proposed approach performs well in practice.     

A unified framework for off-line permutation routing in parallel networks

In this paper we present a general strategy for finding efficient permutation routes in parallel networks. Among the popular parallel networks to which the strategy applies are mesh networks, hypercube networks, hypercube-derivative networks, ring networks, and star networks. The routes produced are generally congestion-free and take a number of routing steps that is within a small constant factor of the diameter of the network. Our basic strategy is derived from an algorithm that finds (in polynomial time) efficient permutation routes for aproduct network, G×H, given efficient permutation routes forG andH. We investigate the use of this algorithm for routingmultiple permutations and extend its applicability to a wide class of graphs, including several families ofCayley graphs. Finally, we show that our approach can be used to find efficient permutation routes among the remaining live nodes infaulty networks.This research was supported in part by a grant from the NSF, Grant No. CCR-88-12567.     

From means to ends: The transformation of ERP in a manufacturing company

In this paper, we present a case study of the restructuring of an Enterprise Resource Planning (ERP) system within a manufacturing company, in particular the combination of Material Requirement Planning (MRP) with a Just In Time (JIT) material management procedure at the assembly lines. We focus in this study upon the mutual shaping of technology and organizational culture, in particular the virtualization of the organization. It is argued that the implementation of ERP in this specific context was more than an adaptation of a standardized information system relative to organizational requirements, and that the organizational adaptations were more than a re-engineering of business processes relative to ERP. Instead, we suggest that in this case the ERP system itself has been transformed, including a change in the signification of ERP within the company.     

A game theoretic framework for stochastic multipath routing in self-organized MANETs

In this paper we propose a game theoretic framework for stochastic multipath routing in mobile ad hoc networks (MANETs). In a MANET, intelligent and adaptive attackers may try to hijack, jam or intercept data packets traveling from source to destination. In our proposed game, at each stage the source node keeps track of the available multiple paths, the residual bandwidth of the paths and the strategy of the attackers from the information gathered during the previous stage. Based on these observations, the source node selects a path for data communication and switching strategy among the multiple established paths between the source node and the destination node. Accordingly, it selects an optimal routing strategy to send data packets to the destination at each stage of the game. Using minimax-Q learning, the selected routing strategy maximizes the expected sum of per stage discounted payoff, which is the utilization of residual bandwidth between a source–destination pair along with the probability that the path is safe. Performance analysis and numerical results show that our proposed scheme achieves significant performance gains in terms of residual bandwidth utilization, average end-to-end delay, packet delivery ratio, routing overhead and security.     

Arc routing in a node routing environment

We describe a special variant of the vehicle routing problem (VRP), where there are many customers per road segment. This class of VRPs arises in, e.g. mail delivery, and is a borderline case where both arc routing and node routing techniques may be applied for modeling and solving. In a real-world setting, the problem should be modeled so as to incorporate all important constraining factors. We use a simplified node routing model and aggregate customers into supernodes to reduce problem size. A tabu search metaheuristic for the standard node routing-based VRP is then applied to the aggregated version of the problem. Our method is tested both on test instances from the literature as well as on a portfolio of new test instances especially made to fit the problem at hand. Experimental results are reported, showing that aggregation of customers can lead to substantial improvements both in solution time and solution quality in this setting, especially for larger instances.     

EMSC: a joint multicast routing,scheduling, and call admission control in multi–radio multi–channel WMNs

This paper deals with the problem of joint multicast routing, scheduling, and call admission control in multiradio multi-channel wireless mesh networks. To heuristically solve this problem, we propose a cross-layer algorithm named “extended MIMCR with scheduling and call admission control phases (EMSC)”. Our model relies on the ondemand quality of service (QoS) multicast sessions, where each admitted session creates a unique tree with a required bandwidth. The proposed scheme extends the MIMCR algorithm to fairly schedule multiple non-interfering transmissions in the same time slot. It also exploits a call admission control mechanism to protect the QoS requirements of the multicast traffics. EMSC reduces the number of occupied time slots, with consideration of spatial reuse, both Intra-flow and Inter-flow interferences, and selecting the minimuminterference minimum-cost paths. This subsequently leads to better radio resource utilization and increases the network throughput. Simulation results show that the proposed algorithm outperforms the other algorithms and improves the network performance.     

Frog call classification: a survey

Over the past decade, frog biodiversity has rapidly declined due to many problems including habitat loss and degradation, introduced invasive species, and environmental pollution. Frogs are greatly important to improve the global ecosystem and it is ever more necessary to monitor frog biodiversity. One way to monitor frog biodiversity is to record audio of frog calls. Various methods have been developed to classify these calls. However, to the best of our knowledge, there is still no paper that reviews and summarizes currently developed methods. This survey gives a quantitative and detailed analysis of frog call classification. To be specific, a frog call classification system consists of signal pre-processing, feature extraction, and classification. Signal pre-processing is made up of signal processing, noise reduction, and syllable segmentation. Following signal preprocessing, the next step is feature extraction, which is the most crucial step for improving classification performance. Features used for frog call classification are categorized into four types: (1) time domain and frequency domain features (we classify time domain and frequency domain features into one type because they are often combined together to achieve higher classification accuracy), (2) time-frequency features, (3) cepstral features, and (4) other features. For the classification step, different classifiers and evaluation criteria used for frog call classification are investigated. In conclusion, we discuss future work for frog call classification.     

Security in storage: a call for participation

The present treatment of stored critical information, especially personal portable storage, provides inadequate protection. Through many means, the IEEE is examining the issue of security in storage and working to make technologies and standards available that advance the interests of society and protect its many critical functions.     

Evaluation framework for adaptive context-aware routing in large scale mobile peer-to-peer systems

The proliferation of novel wireless network technologies creates new opportunities for complex peer-to-peer information dissemination systems. A key challenge that remains in this area is how to select the best algorithms and protocols to communicate effectively on a large scale. In this paper, we focus in particular on large scale mobile networks where effectiveness depends on the requirements of the application at hand and on the context of the peers in the network. We propose a framework for context-aware adaptive information sharing that allows the evaluation of and comparison with alternative information routing protocols using network metrics to measure a variety of quality attributes of the information dissemination protocols. These metrics can then be used to verify which protocol is best suited for a particular application. We illustrate our evaluation framework with different information dissemination protocols in an inter-vehicle communication scenario.     

The call of duty: Self-organised task allocation in a population of up to twelve mobile robots

Teams with up to 12 real robots were given the mission to maintain the energy stocked in their nest by collecting food-items. To achieve this mission efficiently, we implemented a simple and decentralised task allocation mechanism based on individual activation-thresholds, i.e. the energy level of the nest under which a given robot decides to go collect food-items. The experiments show that such a mechanism — already studied among social insects — results in an efficient dynamical task allocation even under the noisy conditions prevailing in real experiments. Experiments with different team sizes were carried out to investigate the effect of team size on performance and risk of mission failure.