Routing

This paper considers the strategic routing of a fleet of unmanned combat aerial vehicles (UCAVs) to service a set of predetermined targets from a prior surveillance mission. Targets are characterized by their priority or importance level, and minimum and maximum service levels that, respectively, represent the lower bound of munitions for destruction and upper bound of munitions to limit collateral damage. Additional constraints to be respected are the payload capacities of the (possibly heterogeneous) UCAV fleet and the range based on fuel capacity and payload transported. The vital aspect of this paper is the integrated optimal utilization of available resources-weaponry and flight time-while allocating targets to UCAVs and sequencing them to maximize service to targets based on their criticality.

The design of scalable and reliable interconnection net-works for System on Chips (SoCs) introduce new design constraints not present in current multicomputer systems. Although regular topologies are preferred for building NoCs, heterogeneous blocks, fabrication faults and reliabil-ity ...

Advances in wireless personal area networks have made the practical deployment of various services possible, which until a few years ago was considered extremely costly or labor intensive. We build such a wireless sensor network for precision agriculture where real time data of the climatological and other environmental properties are sensed and relayed to a central repository. The architecture comprises of three distinct sections-(a) the sensor-nodes (b) the wireless mesh network and (c) the actuation components. The sensors are selected based on the properties suited for the most common crops and we identify four such attributes. The sensor network is based on the IEEE-802.15.4 standard and we develop a new static routing algorithm suited for the sensing application. The algorithm overrides the deficiency of the Hierarchical Routing scheme inherent in the ZigBee specification where the C skip addressing algorithm limits the possible depth of the network topology due to address wastage. The new algorithm maintains the hierarchical network topology and thus ensures routing at its optimal best. The algorithms for both addressing and routing are provided. The actuation components are also a part of mesh network and are activated wirelessly for controlling irrigation and fertigation.

The efficient implementation of collective communication patterns in a parallel machine is a challenging design effort, that requires the solution of many problems. In this paper we present an in-depth description of how the Quadrics network supports both hardware-and softwarebased collectives. We describe the main features of the two building blocks of this network, a network interface that can perform zero-copy user-level communication and a wormhole routing switch. We also focus our attention on the routing and flow control algorithms, deadlock avoidance and on how the processing nodes are integrated in a global, virtual shared memory. Experimental results conducted on 64-node AlphaServer cluster indicate that the time to complete the hardwarebased barrier synchronization on the whole network is as low as 6 ¡ s, with very good scalability. Good latency and scalability are also achieved with the software-based synchronization, which takes about 15 ¡ s. With the broadcast, similar performance is achieved by the hardware-and software-based implementations, which can deliver messages of up to 256 bytes in 13 ¡ s and can get a sustained asymptotic bandwidth of 288 Mbytes/sec on all the nodes. The hardware-based barrier is almost insensitive to the network congestion, with 93% of the synchronizations taking less than 20 ¡ s when the network is flooded with a background traffic of unicast messages. On the other hand, the software-based implementation suffers from a significant performance degradation. With high load the hardware broadcast maintains a reasonably good latency, delivering messages up to 2KB in 200 ¡ s, while the software broadcast suffers from slightly higher latencies inherited from the synchronization mechanism. Both broadcast algorithms experience a significative performance degradation of the sustained bandwidth with large messages.

In this paper we present new methods for the automated learning of heuristics in knowledge-lean applications and for finding heuristics that can be generalized to unlearned domains. These applications lack domain knowledge for credit assignment; hence, operators for composing new heuristics areg enerally modelfree, domain independent, and syntactic in nature. The operators we have used areg enetics-based; examples of which include mutation and cross-over. Learning is based on a generate-and-test paradigm that maintains a pool of competing heuristics, tests them to a limited extent, creates new ones from those that perform well in the past, and prunes poor ones from the pool. We hav e studied three important issues in learning better heuristics: (a) anomalies in performance evaluation, (b) rational scheduling of limited computational resources in testing candidate heuristics in single-objective asw ell as multiobjective learning, and (c) finding heuristics that can be generalized to unlearned domains. We showexperimental results in learning better heuristics for (a) process placement for distributed-memory multicomputers, (b) node decomposition in a branch-and-bound search, (c) generation of test patterns in VLSI circuit testing, and (d) VLSI cell placement and routing.

Recent measurements show that BGP peering links can fail as frequently as intradomain links and usually for short periods of time. We propose a new fast-reroute technique where routers are prepared to react quickly to interdomain link failures. For each of its interdomain links, a router precomputes a protection tunnel, i.e. an IP tunnel to an alternate nexthop which can reach the same destinations as via the protected link. We propose a BGP-based auto-discovery technique that allows each router to learn the candidate protection tunnels for its links. Each router selects the best protection tunnels for its links and when it detects an interdomain link failure, it immediately encapsulates the packets to send them through the protection tunnel. Our solution is applicable for the links between large transit ISPs and also for the links between multi-homed stub networks and their providers. Furthermore, we show that transient forwarding loops (and thus the corresponding packet losses) can be avoided during the routing convergence that follows the deactivation of a protection tunnel in BGP/MPLS VPNs and in IP networks using encapsulation.

We consider the problems of conflict detection and resolution in air traffic management (ATM) from the perspective of computational geometry and give algo-rithms for solving these problems efficiently. For con-flict resolution, we propose a simple method that can route ...

Less than 116 ps overall clock skew has been achieved across the 15.02 mm/spl times/15.03 mm die by balanced clock path routing and differential clock signal distribution in the global clock tree of 300 MHz 128-bit 2-way superscalar microprocessor. The shared clock wire configuration and clock buffer layout patterns over the whole die enhance the clock skew insensitivity to process

Routing protocols in wireless sensor networks are generally focused on hierarchical infrastructures, for energy saving reasons. In this paper, we intend to give a taxonomy of these approaches identifying three criteria of classification: the assumptions, the algorithms and their evaluation. We classify projects based on these parameters and we also draw a uniform view over them, which may provide a basis of comparison for different routing protocols built atop hierarchical WSN infrastructures.

new distributed algorithm is presented for dynamically determining weighted shortest paths used for message routing in computer networks. The major features of the algorithm are that the paths .defined do not form transient loops when weights change and the number of steps required to find new shortest paths when network links fail is less than for previous algorithms. Specifically, the worst case recovery time is proportional to the largest number of hops h in any of the weighted shortest paths. For previous loop-free distributed algorithms this recovery time is proportional to h2.

We introduce a load-balanced adaptive routing algorithm for torus networks, GOAL -Globally Oblivious Adaptive Locally -that provides high throughput on adversarial traffic patterns, matching or exceeding fully randomized routing and exceeding the worst-case performance of Chaos , RLB [14], and minimal routing [8] by more than 40%. GOAL also preserves locality to provide up to 4.6× the throughput of fully randomized routing [19] on local traffic. GOAL achieves global load balance by randomly choosing the direction to route in each dimension. Local load balance is then achieved by routing in the selected directions adaptively. We compare the throughput, latency, stability and hot-spot performance of GOAL to six previously published routing algorithms on six specific traffic patterns and 1,000 randomly generated permutations.

Virtual backbone trees have been used for efficient communication between sink node and any other node in the deployed area. But all the proposed virtual backbone trees are not fully energy efficient and EVBTs have few flaws associated with them. In this paper two such virtual backbones are proposed. The motive behind the first algorithm, Most Minimal Energy Virtual Backbone Tree (MMEVBT), is to minimise the energy consumption when packets are transmitted between sink and a target sensor node. The energy consumption is most minimal and optimal and it is shown why it always has minimal energy consumption during any transfer of packet between every node with the sink node. For every node, route path with most minimal energy consumption is identified and a new tree node is elected only when a better minimal energy consumption route is identified for a node to communicate with the sink and vice versa. By moving sink periodically it is ensured the battery of the nodes near sink is not completely drained out. Another backbone construction algorithm is proposed which maximises the network lifetime by increasing the lifetime of all tree nodes. Simulations are done in NS2 to practically test the algorithms and the results are discussed in detail.

We present a model of energy consumption in IP networks. Using this model, we identify energy ldquohotspotsrdquo and estimate how energy consumption will grow with increasing network capacity. Todaypsilas Internet uses less than 1% of the available electricity supply. However, network energy consumption could grow substantially as access rates increase.

Delay-Tolerant network (DTN) is a network in which no simultaneous end-to-end path exists. And the messages delivered in the DTN usually have large delivery latency due to network partition. These special characteristics make DTN routing a challenging problem. For this purpose, we updated the shortest path based routing algorithms using conditional intermeeting times and proposed to route the messages over conditional shortest paths. This proposes Conditional Shortest Path Routing (CSPR) protocol that route the messages over conditional shortest paths in which the cost of links between nodes is defined by conditional intermeeting times rather than the conventional intermeeting times.

This paper investigates communication in distributed memory multiprocessors to support tasklevel parallelism for real-time applications. It is shown that wormhole routing, used in second generation multicomputers, does not support task-level pipelining because its oblivious contention resolution leads to output inconsistency in which a constant throughput is not guaranteed. We propose scheduled routing which guarantees constant throughputs by integrating task specifications with flow-control. In this routing technique, communication processors provide explicit flowcontrol by independently executing switching schedules computed at compile-time. It is deadlock-free, contention-free, does not load the intermediate node memory, and makes use of the multiple equivalent paths between non-adjacent nodes. The resource allocation and scheduling problems resulting from such routing are formulated and related implementation issues are anal yzed. A comparison with wormhole routing for various generalized hyp ercubes and tori shows that scheduled routing is effective in providing a constant throughput when wormhole routing does not and enables pipelining at higher input arrival rates.

This paper presents a framework that develops algorithms for solving combined locational and multihop routing optimization problems. The objective is to determine resource node locations in a multiagent network and to specify the multihop routes from each agent to a common destination through a network of resource nodes that minimize total communication cost. These problems are computationally complex (NP-hard) where

NFV-based network implements a variety of network functions with software on general-purpose servers and this allows the network operator to select any capacity and location of network functions without any physical constraints. It is essential for economical NFV-based network design to determine the place where each network function should be located in the network and what its capacity should be. The authors proposed an algorithm of virtual routing function allocation in the NFV-based network for minimizing the network cost and provided effective allocation guidelines for virtual routing functions. This paper proposes the deployment algorithm of virtual firewall function in addition to virtual routing function for minimizing the network cost. Our evaluation results have revealed the following: (1) Installing a packet filtering function, which is a part of the firewall function, in the sending-side area additionally can reduce wasteful transit bandwidth and routing processing and thereby reduce the network cost. (2) The greater the number of packets filtered by packet filtering function in the sending-side area, the more the reduction of network cost is increased. (3) The greater the bandwidth cost relative to the routing function cost, the greater the effect of statistical multiplexing on reducing the network cost. (4) The proposed algorithm would be approaching about 95% of the deployment with the optimal solution.

Mobile ad-hoc networks (MANETs) consist of special kind of wireless mobile nodes which form a temporary network without using any infrastructure or centralized administration. MANETs can be used in wide range of future applications as they have the capability to establish networks at anytime, anywhere without aid of any established infrastructure. It is a challenging task to find most efficient routing due to the changing topology and the dynamic behavior of the nodes in MANET. It has been found that ant colony optimization (ACO) algorithms can give better results as they are having characterization of Swarm Intelligence (SI) which is highly suitable for finding the adaptive routing for such type of volatile network. ACO algorithms are inspired by a foraging behavior of group of ants which are able to find optimal path based upon some defined metric which is evaluated during the motion of ants. ACO routing algorithms use simple agents called artificial ants which establish optimum paths between source and destination that communicate indirectly with each other by means of stigmergy. Keeping in view of the above, in this paper we provide a taxonomy of various ant colony algorithms with advantages and disadvantages of each others with respect to various metrics.

Network on Chip is an efficient on-chip communication architecture for SoC architectures. It enables the integration of a large number of computational and storage blocks on a single chip. The router is the basic element of NoC with multiple, connecting to other router and to a local IP core. This router architecture can be used later for building a NoC with standard or arbitrary topology with low latency and high speed and High maximal peak performance. The low latency and high speed is achieved by allowing for each input port a routing function which runs in parallel with Link controler and with distributed arbiters. To evaluate our approach, A wormhole input queued 2-D mesh router was created to verify the capability of our router. Various parameterized designs were synthesized to provide a comparative study with other implementations in FPGA thechnology, with different flit size.

We propose a market-managed QoS (Quality of Service) interconnection model for heterogeneous networking environments. The deployment of this model will help autonomous systems to reduce the cost of their network services as well as increase social welfare. We describe a technical solution for a next generation Internet, where networks are managed based on either technology requirements (QoS networks) or market principles (market-managed networks). Our solution requires two technologies: BMP (Bandwidth Management Point) and a modified version of BGP (Border Gateway Protocol). The modified version of BGP, as proposed in this paper, provides additional routing exchange information such as price and QoS level specifications. Both technologies are discussed with regard to the impact on routing, QoS provisioning, and charging. In order to show the benefit of our approach for inter-domain routing and interconnection, we present some analytical and simulation results, showing the significant increase in network service revenue as well as the increase in social welfare. These results draw important implications for designing the next generation Internet with regard to investment in QoS networks.

In this paper, we focus on broadband wireless mesh networks like 3GPP LTE-Advanced. This technology is a key enabler for next generation cellular networks which are about to increase by an order of magnitude the capacity provided to users. Such an objective needs a significative densification of cells which requires an efficient backhauling infrastructure. In many urban areas as well as under-developed countries, wireless mesh networking is the only available solution. Besides, economical and environmental concerns require that the energy expenditure of such infrastructure is optimized.

This paper investigates implementation and design issues for a heterogeneous network for structural monitoring. The proposed application uses wireless sensors and the controller area network (CAN) to provide energy efficient monitoring. The contributions include: implementation of the PIC18f4680 platform in TinyOS, creating a message protocol over CAN, and developing a sensor board.

Abstract Summary form only given. In a broadcasting problem, a message is sent from a source to all the other nodes in the network. Blind flooding is a classical mechanism for broadcasting, where each node retransmits received message to all its neighbors. We ...

The AS-level topology of the Internet has been quite a hot research topic in the last few years. However, only a small number of studies have been developed that give a structural interpretation of this graph. Such an interpretation is crucially important in order to test protocols and optimal routing algorithms, to design efficient networks, and for failure detection purposes. Moreover, most research does not highlight the role that IXPs have on the AS-level structure of the Internet, although their role is recognized as fundamental. The initial contribution of this study is an analysis of the most important AS-level topologies that are publicly found on the web and an analysis of the topology obtained when they are merged. We compiled structural information from this topology making considerable use of the k-core decomposition technique to delineate various particular classes of nodes. Next, we associated node properties with a reasonable modus operandi of the ASs on the Internet. The second contribution is a study of the impact that ASs connected to IXPs and BGP connections crossing IXPs have on the AS-level topology. To achieve this, we developed a procedure to gather reliable information related to IXPs and their participants. 1 The IPv4 Routed /24 AS Links Dataset, Y.

Abstract. Distributed denial of service (DDoS) attacks are a serious problem in the present-day Internet. We consider the design of a scalable agent-based system for collecting information about the structure and dynamics of DDoS attacks. Our system requires ...

This chapter introduces the topic of wireless sensor networks from the applications perspective. A wireless sensor network consists of a possibly large number of wireless devices able to take environmental measurements such as temperature, light, sound, and humidity. These sensor readings are transmitted over a wireless channel to a running application that makes decisions based on these sensor readings. Authors describe some examples of proposed wireless sensor applications, and consider the following two questions to motivate an application-based viewpoint. What aspects of wireless sensors make the implementation of applications more challenging, or at least different? One widely recognized issue is the limited power available to each wireless sensor node, but there are other challenges such as limited storage or processing. What services are required for a wireless sensor network application to achieve its intended purpose? A number of widely applicable services, such as time synchronization and location determination are briefly discussed in this chapter. Other services are needed to support database requirements, such as message routing, topology management, and data aggregation and storage. As most of these topics are covered in separate chapters, this chapter serves to provide a broad framework to enable the reader to see how these different topics tie together into a cohesive set of capabilities for building wireless sensor network applications.

Wireless Sensor Network depends on nodes have limited energy, memory, computational power, range and it is important to increase energy efficiency by saving the battery power so as to extend the life time of the given WSN deployment. In WSN, data is measured by nodes and same is send to Base Station at regular interval. Different protocols are used for energy consumption, in wireless sensor network. In this paper for energy consumption in wireless sensor network we study about LEACH protocol, EEUC protocol and zone-divided and energy-balanced clustering routing protocol (ZECR) which divides the area into several zones according to the distance and uses the clustering method among these zones. The key idea of these protocols is that within a cluster there is a -cluster-head‖ which receive the data from remaining nodes and such data is sent to base station.

In this paper we present a tabu search algorithm for the min-max k-Chinese postman problem (MM k-CPP). Given an undirected edge-weighted graph and a distinguished depot node, the MM k-CPP consists of finding k > 1 tours (starting and ending at the depot node) such that each edge is traversed by at least one tour and the length of the longest tour is minimized. A special emphasis is put on investigating the trade-off between running time effort and solution quality when applying different improvement procedures in the course of the neighborhood construction. Furthermore, different neighborhoods are analyzed. Extensive computational results show that the tabu search algorithm outperforms all known heuristics and improvement procedures. Scope and purpose Given a road network, the Chinese postman problem (CPP) is to find the shortest postman tour covering all the roads in the network. Applications of the CPP include road maintenance, garbage collection, mail delivery, etc. Since usually large road networks have to be serviced the work load must be distributed among k 2 vehicles. In contrast to the usual objective to minimize the total distance traveled by the k vehicles (k-CPP), for the min-max k-Chinese postman problem (MM k-CPP) the aim is to minimize the length of the longest of the k tours. This kind of objective is preferable when customers have to be served as early as possible. Furthermore, tours will be enforced to be more balanced resulting in a fair scheduling of tours. Although the CPP and the k-CPP are polynomially solvable, the MM k-CPP is NP-hard. Hence, we must rely on heuristics producing approximate solutions. The purpose of this paper is to present a tabu search algorithm for the MM k-CPP which outperforms all known heuristics. In many cases we obtained solutions which could be proved to be near-optimal or even optimal.

This paper studies the stochastic vehicle routing problem with soft time windows (SVRPSTW). Vehicles with limited capacity are routed from the central depot to a set of geographically dispersed customers with unknown demands, predefined presence probability and time windows. The late arrival at the customer is allowed by adding a penalty to the objective value. A mathematical model is developed to describe the behavior of this kind of delivery system. A novel age based genetic scheduling algorithm is proposed as an optimization tool to solve this intractable vehicle routing problem in order to minimize the total cost. The effectiveness of the proposed scheduling algorithm is illustrated by using a set of randomly generated numerical examples. The results indicate that the proposed genetic approach is a simple but effective means for solving these problems.

The location routing problem (LRP) appears as a combination of two difficult problems: the facility location problem (FLP) and the vehicle routing problem (VRP). In this work, we consider a discrete LRP with two levels: a set of potential capacitated distribution centres (DC) and a set of ordered customers. In our problem we intend to determine the set of installed DCs as well as the distribution routes (starting and ending at the DC). The problem is also constrained with capacities on the vehicles. Moreover, there is a homogeneous fleet of vehicles, carrying a single product and each customer is visited just once. As an objective we intend to minimize the routing and location costs.

The automation of engineering processes through Knowledge Based Engineering methods and technologies can provide significant savings in project scheduling and cost, increasing competitiveness in a changing aerospace market. In this paper we present outcomes of a research project aimed at improving engineering automation capability through development of a system for automatic rule based path-finding for the complex engineering task of aircraft electrical harness and pipe routing.

This letter proposes the enhanced hierarchical routing protocol (EHRP) for ZigBee Mesh Networks. The EHRP finds the shortest hierarchical path based on the ZigBee hierarchical addressing scheme. The EHRP provides efficient and reliable routing paths. In addition, the EHRP is completely compatible with ZigBee v.1.0 standard. Simulation results demonstrate that the EHRP reduces routing overhead and route discovery delay of ZigBee mesh networks significantly compared with the hierarchical routing protocol (HRP) defined in ZigBee v1.0.

Underwater Wireless Sensor Network (UWSN) is a particular kind of sensor networks which is characterized by using acoustic channels for communication. UWSN is challenged by great issues specially the energy supply of sensor node which can be wasted rapidly by several factors. The most proposed routing protocols for terrestrial sensor networks are not adequate for UWSN, thus new design of routing protocols must be adapted to this constrain. In this paper we propose two new clustering algorithms based on Fuzzy C-Means mechanisms. In the first proposition, the cluster head is elected initially based on the closeness to the center of the cluster, then the node having the higher residual energy elects itself as a cluster head. All non-cluster head nodes transmit sensed data to the cluster head. This latter performs data aggregation and transmits the data directly to the base station. The second algorithm uses the same principle in forming clusters and electing cluster heads but operates in multi-hop mode to forward data
from cluster heads to the underwater sink (uw-sink). Furthermore the two proposed algorithms are tested for static and dynamic deployment. Simulation results demonstrate the effectiveness of the proposed algorithms resulting in an extension of the network lifetime.

Order picking has long been identified as the most labour-intensive and costly activity for almost every warehouse; the cost of order picking is estimated to be as much as 55% of the total warehouse operating expense. Any underperformance in order picking can lead to unsatisfactory service and high operational cost for its warehouse, and consequently for the whole supply chain. In order to operate efficiently, the orderpicking process needs to be robustly designed and optimally controlled. This paper gives a literature overview on typical decision problems in design and control of manual order-picking processes. We focus on optimal (internal) layout design, storage assignment methods, routing methods, order batching and zoning. The research in this area has grown rapidly recently. Still, combinations of the above areas have hardly been explored. Order-picking system developments in practice lead to promising new research directions.

Abstract—There are many classical algorithms for finding routing in FPGA. But Using DNA computing we can solve the routes efficiently and fast. The run time complexity of DNA algorithms is much less than other classical algorithms which are used for solving routing in FPGA. The ...

In this paper we consider the daily aircraft routing and scheduling problem (DARSP). It consists of determining daily schedules which maximize the anticipated profits derived from the aircraft of a heterogeneous fleet. This fleet must cover a set of operational flight legs ...

This paper describes the concept of sensor networks which has been made viable by the convergence of microelectro-mechanical systems technology, wireless communications and digital electronics. First, the sensing tasks and the potential sensor networks applications are explored, and a review of factors influencing the design of sensor networks is provided. Then, the communication architecture for sensor networks is outlined, and the algorithms and protocols developed for each layer in the literature are explored. Open research issues for the realization of sensor networks are also discussed. Ó 2002 Published by Elsevier Science B.V.