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1
Yang, Xinan. "Top-percentile traffic routing problem." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/5883.
Повний текст джерелаАнотація:
Multi-homing is a technology used by Internet Service Provider (ISP) to connect to the Internet via multiple networks. This connectivity enhances the network reliability and service quality of the ISP. However, using multi-networks may imply multiple costs on the ISP. To make full use of the underlying networks with minimum cost, a routing strategy is requested by ISPs. Of course, this optimal routing strategy depends on the pricing regime used by network providers. In this study we investigate a relatively new pricing regime – top-percentile pricing. Under top-percentile pricing, network providers divide the charging period into several fixed length time intervals and calculate their cost according to the traffic volume that has been shipped during the θ-th highest time interval. Unlike traditional pricing regimes, the network design under top-percentile pricing has not been fully studied. This paper investigates the optimal routing strategy in case where network providers charge ISPs according to top-percentile pricing. We call this problem the Top-percentile Traffic Routing Problem (TpTRP). As the ISP cannot predict next time interval’s traffic volume in real world application, in our setting up the TpTRP is a multi-stage stochastic optimisation problem. Routing decisions should be made at the beginning of every time period before knowing the amount of traffic that is to be sent. The stochastic nature of the TpTRP forms the critical difficulty of this study. In this paper several approaches are investigated in either the modelling or solving steps of the problem. We begin by exploring several simplifications of the original TpTRP to get an insight of the features of the problem. Some of these allow analytical solutions which lead to bounds on the achievable optimal solution. We also establish bounds by investigating several “naive” routing policies. In the second part of this work, we build the multi-stage stochastic programming model of the TpTRP, which is hard to solve due to the integer variables introduced in the calculation of the top-percentile traffic. A lift-and-project based cutting plane method is investigated in solving the SMIP for very small examples of TpTRP. Nevertheless it is too inefficient to be applicable on large sized instances. As an alternative, we explore the solution of the TpTRP as a Stochastic Dynamic Programming (SDP) problem by a discretization of the state space. This SDP model gives us achievable routing policies on small size instances of the TpTRP, which of course improve the naive routing policies. However, the solution approach based on SDP suffers from the curse of dimensionality which restricts its applicability. To overcome this we suggest using Approximate Dynamic Programming (ADP) which largely avoids the curse of dimensionality by exploiting the structure of the problem to construct parameterized approximations of the value function in SDP and train the model iteratively to get a converged set of parameters. The resulting ADP model with discrete parameter for every time interval works well for medium size instances of TpTRP, though it still requires too long to be trained for large size instances. To make the realistically sized TpTRP problem solvable, we improve on the ADP model by using Bezier Curves/Surfaces to do the aggregation over time. This modification accelerates the efficiency of parameter training in the solution of the ADP model, which makes the realistically sized TpTRP tractable.
2
Mazandu, Gaston Kuzamunu. "Traffic Engineering using Multipath Routing Approaches." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/679.
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3
Guedrez, Rabah. "Enabling traffic engineering over segment routing." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2018. http://www.theses.fr/2018IMTA0116/document.
Повний текст джерелаАнотація:
La majorité des grands opérateurs utilise la technologie MPLS pour gérer leur réseau via des protocoles de signalisation et de distributions de labels. Or, ces protocoles sont complexes à déployer, à maintenir et la résolution des pannes est souvent très difficile. L'IETF a initié la standardisation d'une architecture de routage par segments (Segment Routing) s'appuyant sur un plan de contrôle simple, léger, facile à gérer et instanciée sur MPLS ou IPv6. Cette architecture repose sur le concept de routage à la source, dans lequel l'en-tête des paquets transporte les indications du chemin à suivre pour atteindre sa destination. Adapté aux cas d'usages simples et offrant nativement une résistance aux pannes, les cas d'usages plus complexes exigent de résoudre des verrous technologiques pour lesquels nous proposons plusieurs solutions. Dans cette thèse effectuée au sein d'Orange Labs, nous nous sommes intéressés à l'instanciation de l'architecture Segment Routing sur le plan de transfert MPLS et plus particulièrement à l'ingénierie de trafic, notamment avec réservation de ressources. Nous avons proposé des solutions aux problèmes liés à la limitation matérielle des routeurs actuels ne permettant pas l'expression de tous les chemins contraints. Ce travail est divisé en deux parties : (i) la proposition d'algorithmes de calcul et d'encodage de chemins de routage par segment afin de contourner les limitations matérielles. (ii) la définition des exigences architecturales et la construction d'une preuve de concept fonctionnelle. Enfin, cette thèse propose de nouvelles pistes d'études afin de consolider les outils d'ingénierie de trafic pour le routage par segmentMost major operators use MPLS technology to manage their network via signalling and label distribution protocols. However, these protocols are complex to deploy, maintain and troubleshooting is often very difficult. The IETF has initiated the standardization of a segment routing architecture based on a simple control plane, lightweight, easyto-manage and instantiated on MPLS or IPv6. This architecture is based on the concept of source routing, in which the packet header carries the indications of the path to follow to reach its destination. Suitable for simple use cases and natively resistant to failure, more complex use cases require the resolution of technological issues for which we offer several solutions.In this thesis carried out within Orange Labs, we were interested in the instantiation of the Segment Routing architecture on the MPLS transfer plan and more particularly in traffic engineering, particularly with resource reservation. We have proposed solutions to the problems related to the hardware limitation of current routers that do not allow the expression of all constrained paths. This work is divided into two parts : (i) the proposal of algorithms for computing and encoding segment routing paths in order to bypass hardware limitations. (ii) the definition of architectural requirements and the construction of a functional proof of concept. Finally, this thesis proposes new research issues to consolidate traffic engineering tools for segment routing
4
Lindblad, Andreas. "Routing of traffic in an IP-network using combined routing patterns." Thesis, Linköpings universitet, Optimeringslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119973.
Повний текст джерелаАнотація:
In IP networks using the OPSF-principle together with the ECMP-principle, thetraffic is routed in all shortest paths. Weights on links are set by an administrator,not knowing how the resulting routing pattern will become. In this final thesis, I givea heuristic solution to the problem of changing a set of desired routing patterns inan ordered way to make them compatible with each other. An implementation of thealgorithm has been made and some testing with provided data for performance is alsopresented.
5
He, Jenny Jing. "Optical flow routing : a routing and switching paradigm for the core optical networks." Thesis, University of Essex, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248654.
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6
Gellman, Michael. "Quality of service routing for real-time traffic." Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/12026.
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7
Tillotson, Peter J. "Multi-agent learning for TCP/IP traffic routing." Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399051.
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8
Sengupta, Sudipta 1974. "Efficient and robust routing of highly variable traffic." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/35532.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2006.Includes bibliographical references (p. 316-324).
Many emerging applications for the Internet are characterized by highly variable traffic behavior over time that is difficult to predict. Classical approaches to network design rely on a model in which a single traffic matrix is estimated. When actual traffic does not conform to such assumptions, desired bandwidth guarantees cannot be provided to the carried traffic. Currently, Internet Service Providers (ISPs) use gross capacity over-provisioning and manual routing adaptation to avoid network congestion caused by unpredictable traffic. These lead to increased network equipment and operational costs. Development of routing infrastructures that optimize network resources while accommodating extreme traffic unpredictability in a robust and efficient manner will be one of the defining themes in the next phase of expansion of the Internet. This thesis proposes two-phase routing as a capacity efficient and robust strategy for handling highly variable traffic. The scheme allows preconfiguration of the network such that all traffic patterns permissible within the network's natural ingress-egress capacity constraints can be routed with bandwidth guarantees without requiring detection of traffic changes in real-time or reconfiguring the network in response to it.
(cont.) The scheme routes traffic in two phases -- traffic entering the network is sent from the source to a set of intermediate nodes in predetermined split ratios that depend on the intermediate nodes, and then from the intermediate nodes to the final destination. The scheme has the desirable properties of supporting static optical layer provisioning in IP-over-Optical networks and indirection in specialized service overlay models unlike previous approaches -- like direct source-destination path routing - for handling variable traffic. This thesis represents the first comprehensive study, problem formulation, and algorithm design for many aspects of two-phase routing. Our contributions can be grouped into three broad parts. First, we consider the problems of minimum cost network design and maximum throughput network routing for the scheme. We give a simple solution for minimum cost network design. For maximum throughput network routing. we design linear program.ling based and combinatorial algorithms. We show how the algorithms can handle a total cost constraint for maximum throughput two-phase routing. This can be used to solve the link capacitate version of minimum cost two-phase routing.
(cont.) We establish theoretical bounds on the resource requirements of two-phase routing under throughput and cost models with respect to the optimal scheme that is allowed to make the routing dynamically dependent on the current traffic matrix. We also generalize the traffic split ratios to depend not only on the intermediate nodes but also on source and destination of traffic and solve the corresponding optimization problems. Second, we consider making two-phase routing resilient to network failures. Two-phase routing in IP-over-Optical networks can be protected against router node failures through redistribution of traffic split ratio for the failed router node to other intermediate nodes. We propose two different schemes for provisioning the optical layer to handle router node failures. We develop linear programming formulations for both schemes and a fast combinatorial algorithm for the second scheme so as to maximize network throughput. Two-phase routing can be made resilient against link failures by protecting the first and second phase paths using pre-provisioned restoration mechanisms. We consider three such restoration mechanisms - local (link/span) restoration, K-route path restoration, and shared backup path restoration.
(cont.) We provide linear programming formulations and combinatorial algorithms for maximum throughput two-phase routing with local restoration and K-route path restoration. We show that the problem of maximum throughput two-phase routing with shared backup path restoration is JVP-hard. Assuming an approximation oracle for a certain disjoint paths problem (which we also show to be AP-hard), we design a combinatorial algorithm with provable guarantees. Third, we consider the application of two-phase routing to multi-hop Wireless Mesh Networks (WMNs). These networks have recently been of much research interest due to their lowered need for wired infrastructure support and due to envisaged new applications like community wireless networks. We extend our optimization framework for maximum throughput two-phase routing in wired networks to handle routing and scheduling constraints that are peculiar to WMNs and arise from the requirement to handle radio transmit/receive diversity and the phenomenon of wireless link interference. We evaluate various aspects of two-phase routing on actual ISP topologies using the developed algorithms. For the WMN application, we use randomly generated WMN topologies for the evaluations.
by Sudipta Sengupta.
Ph.D.
9
Tajtehranifard, Hasti. "Incident duration modelling and system optimal traffic re-routing." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/110525/1/Hasti_Tajtehranifard_Thesis.pdf.
Повний текст джерелаАнотація:
Traffic incidents are among the most significant contributory factors to congestion, particularly in metropolitan areas. In this dissertation, we have developed state-of-the-art statistical models to provide in-depth insights into how various incident-specific characteristics and the associated temporal and spatial determinants impact freeway incident durations. Next, we have proposed, developed and tested two novel and computationally efficient System Optimal incident traffic re-routing algorithms that provide optimal traffic flow patterns, for minimized total system travel time. Specifically, a single-destination System Optimal Dynamic Traffic Assignment model and a multi-destination System Optimal Quasi-Dynamic Traffic Assignment model are proposed, developed and demonstrated to improve total system travel times, both under incident-free and incident scenarios.
10
Gao, Ruomei. "Interdomain Traffic Engineering for Multi-homed Networks." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19732.
Повний текст джерелаАнотація:
Interdomain traffic engineering (TE) controls the flow of traffic
between autonomous systems (ASes) to achieve performance goals under
various resource constraints. Interdomain TE can be categorized
into ingress TE and egress TE, which aim to control the ingress and
egress traffic flow in a network, respectively. Most interdomain TE
techniques are based on BGP, which was not designed to support
performance based routing. Hence even though some basic interdomain
TE techniques are widely deployed, their overall effectiveness and
impact on interdomain traffic are not well understood. Furthermore,
systematic practices for deploying these techniques have yet to be
developed.
In this thesis, we explore these open issues for both ingress and
egress TE. We first focus on the AS-Path prepending technique in
interdomain ingress TE. We design a polynomial algorithm that
takes network settings as input and produces the optimal prepending
at each ingress link. We also develop methods to measure the inputs
of the optimal algorithm by leveraging widely available looking
glass severs and evaluate the errors of such measurement. We
further propose an algorithm, based on this optimal algorithm, that
is robust to input errors.
We then focus on Intelligent Routing Control (IRC) systems often
used at multihomed networks for egress interdomain TE. To address
the possible traffic oscillation problem caused by multiple IRC
systems, we design a class of randomized IRC algorithms. Through
simulations, we show that the proposed algorithms can effectively
mitigate oscillations. We also show that IRC systems using
randomized path switching algorithms perform better than those
switching path deterministically, when both types of IRC systems
co-exist.
To further understand the performance impact of IRC systems, we next
focus on the performance of applications, such as TCP
connections. We study the synergistic and antagonistic
interactions between IRC and TCP connections, through a simple
dual-feedback model. We first examine the impact of sudden RTT and
available bandwidth changes in TCP connection. We then examine the
effect of IRC measurement delays on closed loop traffic. We also
show the conditions under which IRC is beneficial under various path
impairment models.
11
Sheu, Hsin-Teng. "A coordinated decentralized flow and routing control algorithm for an automated highway system /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu148758564557836.
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12
Teixeira, António Edgar Carvalho. "Simple and stable dynamic traffic engineering for provider scale ethernet." Master's thesis, Faculdade de Ciências e Tecnologia, 2010. http://hdl.handle.net/10362/4998.
Повний текст джерелаАнотація:
Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia InformáticaThe high speeds and decreasing costs of Ethernet solutions has motivated providers’ interest in using Ethernet as the link layer technology in their backbone and aggregation networks. Provider scale Ethernet offers further advantages, providing not only an easy to manage solution for multicast traffic, but also transparent interconnection between clients’ LANs. These Ethernet deployments face altogether different design issues, requiring support for a significantly higher number of hosts. This support relies on hierarquization, separating address and virtual network spaces of customers and providers. In addition, large scale Ethernet solutions need to grant forwarding optimality. This can be achieved using traffic engineering approaches. Traffic engineering defines the set of engineering methods and techniques used to optimize the flow of network traffic. Static traffic engineering approaches enjoy widespread use in provider networks, but their performance is greatly penalized by sudden load variations. On the other hand, dynamic traffic engineering is tailored to adapt to load changes. However, providers are skeptical to adopt dynamic approaches as these induce problems such as routing instability, and as a result, network performance decreases. This dissertation presents a Simple and Stable Dynamic Traffic Engineering framework (SSD-TE), which addresses these concerns in a provider scale Ethernet scenario. The validation results show that SSD-TE achieves better or equal performance to static traffic engineering approaches, whilst remaining both stable and responsive to load variations.
13
Guo, Yu. "Multi-plane routing for fast failure recovery and traffic engineering." Thesis, University of Surrey, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538032.
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14
Al-Qassas, Raad S. "On the performance of traffic-aware reactive routing in MANETs." Thesis, University of Glasgow, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443330.
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15
Staats, Richard C. (Richard Charles). "Integration of predictive routing information with dynamic traffic signal control." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/35433.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaves 306-310).
by Richard C. Staats.
Ph.D.
16
Lim, Sejoon. "Congestion-aware traffic routing for large-scale mobile agent systems." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78452.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 191-201).
Traffic congestion is a serious world-wide problem. Drivers have little knowledge of historical and real-time traffic congestion for the paths they take and often tend to drive suboptimal routes. Congestion phenomena are sure to be influenced by the coming of autonomous cars. This thesis presents route planning algorithms and a system for either autonomous or human-driven cars in road networks dealing with travel time uncertainty and congestion. First, a stochastic route planning algorithm is presented that finds the best path for a group of multiple agents. Our algorithm provides mobile agents with optimized routes to achieve time-critical goals. Optimal selections of agent and visit locations are determined to guarantee the highest probability of task achievement while dealing with uncertainty of travel time. Furthermore, we present an efficient approximation algorithm for stochastic route planning based on pre-computed data for stochastic networks. Second, we develop a distributed congestion-aware multi-agent path planning algorithm that achieves the social optimum, minimizing aggregate travel time of all the agents in the system. As the number of agents grows, congestion created by agents' path choices should be considered. Using a data-driven congestion model that describes the travel time as a function of the number of agents on a road segment, we develop a practical method for determining the optimal paths for all the agents in the system to achieve the social optimum. Our algorithm uses localized information and computes the paths in a distributed manner. We implement the algorithm in multi-core computers and demonstrate that the algorithm has a good scalability. Third, a path planning system using traffic sensor data is then implemented. We predict the traffic speed and flow for each location from a large set of sensor data collected from roving taxis and inductive loop detectors. Our system uses a data-driven traffic model that captures important traffic patterns and conditions using the two sources of data. We evaluate the system using a rich set of GPS traces from 16,000 taxis in Singapore and show that the city-scale congestion can be mitigated by planning drivers' routes, while incorporating the congestion effects generated by their route choices.
by Sejoon Lim.
Ph.D.
17
Day, Jeffrey. "Management of railroad impedances for shortest path-based routing." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/25483.
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18
Prete, Joseph Michael. "Aircraft routing in the presence of hazardous weather." Online access, 2007. http://hdl.handle.net/1951/44608.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Stony Brook University, 2007.This official electronic copy is part of the DSpace Stony Brook theses & dissertations collection maintained by the University Libraries, Special Collections & University Archives on behalf of the Stony Brook Graduate School. It is stored in the SUNY Digital Institutional Repository and can be accessed through the website. Presented to the Stony Brook University Graduate School in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer Science; as recommended and accepted by the candidate's degree sponsor, the Dept. of Computer Science. Includes bibliographical references (p. 92-99).
19
Barros, Joyce Moniz Martim. "Models and methods for Traffic Engineering problems with single-path routing." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/238366.
Повний текст джерелаАнотація:
Traffic Engineering (TE) uses methods and models from a variety of mathematical fields, such as statistics and optimization, to improve the performance of telecommunication networks. In this thesis, we study TE problems dealing with networks that impose single-path routing. As the name infers, in this type of routing, the traffic flow of each "commodity" cannot be split in its path between its origin and destination. Given its cheap cost, single-path routing is widely used in today's data centers, where thousands of stored servers perform computations or host Internet services. One common case of single-path routing is the one enforced by the Spanning Tree Protocol (STP) in switched Ethernet networks. The STP requires the network to keep its activated links loop-free, while maintaining the other redundant links ready for back-up, in case of link failure. The Multiple Spanning Tree Protocol (MSTP) extends the STP by installing multiple virtual networks compliant with the STP, over a single physical topology. Therefore, the MSTP is greatly beneficial for network service providers, as it allows for a more efficient use of the existing resources.Network design problems dealing with the MSTP are generally highly combinatorial and very hard to solve. As such, TE literature mainly suggests heuristic methods, which can quickly produce reasonable designs. Notwithstanding, due to a scarce existence of lower bounds to the optimum values of such problems, there is little knowledge about the quality of the solutions provided by these heuristics.In this sense, we propose mathematical programming models and methods that can provide optimal designs for these networks, or at the very least, obtain valid lower bounds. Taking into mind the goal of avoiding congestion in the network, we focus on two problems that deal with the following load-balancing objectives: the minimization of the worst-case link utilization, and the minimization of flow costs given by piecewise linear functions that penalize heavily-loaded links. The study of both these problems yielded relevant by-products: the first is the study of a MSTP network design problem, where we minimize the total load, and the second is the study of a fundamental unsplittable multicommodity flow problem with piecewise linear costs.For all the considered problems, we provide studies of complexity, extensive polyhedral studies to compare the proposed formulations, and a wide array of computational experiments to evaluate the performance of the proposed models and methods.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
20
Darshana, Dipika. "DELAY SENSITIVE ROUTING FOR REAL TIME TRAFFIC OVER AD-HOC NETWORKS." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2802.
Повний текст джерелаАнотація:
Wireless ad hoc network consists of inexpensive nodes that form a mobile communication network. Due to limitations of the transmission range, the nodes rely on each other to forward packets such that messages can be delivered across the network. The selection of the path along which a packet is forwarded from the source node to the destination node is done by the routing algorithm. Most commonly used routing algorithms, though effective for non-real time applications, cannot handle real-time applications that require strict delay bounds on packet delivery. In this thesis, we propose a routing protocol that ensures timely delivery of real time data packets. The idea is to route packets in such a way that irrespective of factors like traffic load and node density, the average delay remains within acceptable bounds. This is done by carefully accessing the resources available to a route before a session is admitted along that route. Each link in the route is checked for sufficient bandwidth not only for the new session to be admitted but also for the sessions that are already using that link. The new session is admitted only if the admission does not violate the delay bounds of any on-going sessions. This method of route selection coupled with per-hop link reservations allows us to provide bounds on the delay performance. Extensive simulation experiments have been conducted that demonstrate the performance of the proposed routing protocol in terms of throughput, session blocking probability, packet drop probability, average path length, and delay.M.S.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Engineering MSCpE
21
Gao, Song 1976. "Optimal adaptive routing and traffic assignment in stochastic time-dependent networks." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30188.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2005.Includes bibliographical references (p. 233-237).
A stochastic time-dependent (STD) network is defined by treating all link travel times at all time periods as random variables, with possible time-wise and link-wise stochastic dependency. A routing policy is a decision rule which specifies what node to take next out of the current node based on the current time and online information. A formal framework is established for optimal routing policy problems in STD networks, including generic optimality conditions, and a comprehensive taxonomy with insights into variants of the problem. A variant pertinent to road traffic networks is studied in detail, where a discrete joint distribution of link travel times is used to accommodate the most general stochastic dependency among link travel times, and the access to perfect online information about link travel times is assumed. Both exact and approximation solution algorithms are designed and tested. The criteria of optimality are then extended to reliability measures, such as travel time variance and expected early/late schedule delays. The first routing-policy-based stochastic dynamic traffic assignment (DTA) model is established. A general framework is provided and the equilibrium problem is formulated as a fixed point problem with three components: the optimal routing policy generation module, the routing policy choice model and the policy-based dynamic network loader. An MSA (method of successive averages) heuristic is designed. Computational tests are carried out in a. hypothetical network, where random incidents are the source of stochasticity. The heuristic converges satisfactorily in the test network under the proposed test settings. The' adaptiveness in the routing policy based model leads to travel time savings at equilibrium.
(cont.) As a byproduct, travel time reliability is also enhanced. The value of online information is an increasing function of the incident probability. Travel time savings are high when market penetrations are low. However, the function of travel time saving against market penetration is not monotonic. This suggests that in a travelers' information system or route guidance system, the information penetration needs to be chosen carefully to maximize benefits.
by Song Gao.
Ph.D.
22
Cheng, Yufei, and Egemen K. Çetinkaya. "Performance Comparison of Routing Protocols for Transactional Traffic over Aeronautical Networks." International Foundation for Telemetering, 2011. http://hdl.handle.net/10150/595682.
Повний текст джерелаАнотація:
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, NevadaEmerging airborne telemetry networks present several challenges such that traditional MANET protocols do not perform well. On the other hand, application traffic characteristics are expected to be identical in this domain. Transactional application traffic performance has been studied for traditional MANETs, however this type of traffic has not been studied for domain-specific MANET scenarios. We present the simulation model for transactional traffic used in highly-mobile environments. Using the ns-3 simulator, we examine the performance of a domain-specific routing protocol, AeroRP, to route transactional traffic over the aeronautical environment and present performance comparison with two reactive (AODV and DSR) and two proactive (DSDV and OLSR) MANET routing protocols.
23
Yee, George Carleton University Dissertation Information and Systems Science. "Optimal routing in dimensioning communication networks with time-varying traffic demand." Ottawa, 1985.
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24
Zhou, Ji Zhe. "Modeling and dynamic routing for traffic flow through multi-agent system." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3950602.
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25
Pai, Arun S. "Development of deterministic collision-avoidance algorithms for routing automated guided vehicles /." Online version of thesis, 2008. http://hdl.handle.net/1850/7289.
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Sørensen, Anette Ostbø. "An Investigation Into Braess' Paradox and Selfish Routing in Traffic Flow : Solving the non-linear traffic program with linear cost functions on traffic networks." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25619.
Повний текст джерелаАнотація:
The aim of this master thesis was to investigate Braess' Paradox in traffic flow and to look at the effect of selfish routing in optimization of flow distribution on traffic networks. Braess' Paradox is a well known phenomenon in traffic flow. It occurs when extention of a road network by one road leads to increased travel times for all travelers due to a redistribution of the traffic.Selfish routing is about how travelers choose their travel route selfishly. Compared to flow distribution at system optimal flow, selfish routing may result in increased travltime for some or all travelers.The optimal flow distribution was found by a non-linear program, and Nash equilibrium and system optimal flow are achieved with different objective functions. The non-linear program is solved as quadratic programming, since the travel time functions are linear. The method to solve the program was an interior-point method based on a predictor-corrector method. The results of occurences of Braess' paradox are compared to the results from a mathematical characterization of the paradox from the litterature.Four different traffic networks was investigated. The first network was the network model originally used by Braess with one origin and one destination. Furthermore, a network of one origin and two destinations was used, which contributed to two different networks when the direction of two roads were changed. Another network is of two origins and one destination, which also contributed to two networks. Lastly, a three times symmetric network was used, with three origin-destination pairs. Each of the networks were nvestigated to find occurences of Braess' paradox, and to investigate the effect of selfish routing. In the analyses the values of function parameters and demand between origin and destination was changed. In the work it was showed that Braess' paradox occures at some limited intervals of demand, which is dependent on the parameters in the travel time functions. It seems to exist an upper limit for the increase in travel time caused by the added road. The paradox occures when the path with the additional road is utilized together with and at the same time as one or several other paths. Selfish routing affects the travel time when demand is within a limited interval. The travel times at system optimal flow distribution is in some intervals most unfavorable for some of the travelers, compared to the travel time at user optimal flow.
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Tekdogan, Ridvan. "Improving Throughput By Traffic Aware Routing In Non-transparent Ieee 802.16j Networks." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611806/index.pdf.
Повний текст джерелаАнотація:
WiMAX is one of the rising communications technology which enables last mile broadband mobile wireless Internet connectivity. IEEE Std 802.16-2009 is the last accepted standard which targets mobile and fixed wireless broadband access. The standard defines two types of stations which are base and mobile stations. A base station has a wired connection to backhaul network and gives broadband wireless service to mobile stations. IEEE 802.16j standard which is an amendment to IEEE 802.16, introduces Multihop Relaying for increasing coverage and throughput. Deployment of relay stations, where the backbone network does not exist, is a cost effective solution. Two modes of operations are defined for relay station: transparent mode and non-transparent mode. Relays in transparent mode, are deployed for improving signal quality, so that mobile stations can use relay link for increasing throughput. In non-transparent mode, relays can send management packets, so that mobile stations, which are not in the direct reach of a base station, can connect to network through relay stations.
In domain specific networks main data traffic is caused by the communication between subscribers in same region. In this thesis shortcut routing scheme is proposed as sending packets to destination directly through relay station for data traffic between two subscribers with a common relay. With shortcut routing, network throughput is increased by preventing links at higher layer in topology from becoming bottleneck. Moreover, by traversing fewer hops, latency decreases. We also propose traffic aware path selection method, where a path will more.
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Khalaf, Gamal Abdel-Fadeel Mohamed. "Traffic estimation, routing and bandwidth allocation in packet-based speech communication networks." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46388.
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Thiessen, Christian. "Resilient routing and spectrum assignment in Elastic Optical Networks under Dynamic Traffic." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-155684.
Повний текст джерелаАнотація:
Transparent Elastic Optical Networks (EON) are seen as a promising solution for future optical transport networks to keep up with internet traffic growth, as they allow provisioning connections with different bandwidth requirements in an efficient way. To achieve high spectrum efficiency in these networks, making good Routing, Modulation and Spectrum Assignment (RMLSA) decisions is essential. Since fiber cuts are common, resiliency against single-link failures is another important topic. This can be provided efficiently through shared-path protection (SPP), which in turn complicates the RMLSA problem. Existing routing, modulation and spectrum assignment algorithms for SPP focus on the two-step approach, where primary paths are selected independently of their backup path options. However, selecting a different primary path can allow for a better backup path with higher shareability of backup resources if primary and backup path pairs are considered together. Previous studies on SPP in EONs mostly consider the static traffic scenario. Under a dynamic traffic scenario, where unpredictable connection re-quests arrive and terminate over time, fragmentation of spectral resources has a significant impact on the network performance. In this thesis, a new algorithm is proposed for SPP in EONs against single-link failures where primary and backup path pairs are selected jointly, thereby minimizing fragmentation and maximizing shareability which leads to better network performance in terms of blocking probability. Unlike existing algorithms, the primary and backup path and spectrum are decided simultaneously from a set of candidate path pairs and the spectrum assignment is done using a hybrid cost metric. The metric is a weighted combination of existing metrics that integrates fragmentation and shareability into a multi-objective function. Using network traffic simulations in two reference networks, the effect of the different cost functions on the algorithm’s behavior is explored and an optimal set of weights is determined. With this parameterization, traffic simulations in a scaled-down sample US network topology with load values of 190-240 Erlang, corresponding to blocking probabilities of 0.1% to 1%, show an average improvement over the reference algorithm of 79% in blocking probability, 6.9% in shareability and 5.9% in spectrum fragmentation. It is also shown that most of this improvement is caused by joint primary-backup path assignments. The hybrid cost function reduces blocking by a further 10%.Transparenta Elastiska Optiska Nätverk (EON) ses som en lovande lösning för framtida optiska transportnät för att hänga med Internettrafikens tillväxt, eftersom de möjliggör att tillhandahålla förbindelser med olika krav på bandbredd på ett effektivt sätt. För att uppnå hög spektrumeffektivitet i dessa nätverk är det viktigt att fatta bra beslut vad avser routing, modulering och spektrumtilldelning (Routing, Modulation Level and Spectrum Assignment, RMLSA). Eftersom fiberavbrott är vanliga, så är tåligheten mot enstaka länkfel et annat viktigt ämne. Detta kan ske effektivt genom att skydda gemensamma reservvägar (Shared Path Protection, SPP), vilket dock försvårar RMLSA-problemet. Befintliga routing, modulering och spektrumtilldelningsalgoritmer för SPP fokuserar på strategier i två steg, där först de primära vägarna väljs oberoende av deras backupalternativ. Att välja en annan primär väg, kan dock möjliggöra en bättre reservväg med bättre delning av backupresurser om i stället par av primära och sekundära vägar bedöms tillsammans. Tidigare studier på SPP i EONs anser främst statiska trafikscenarier. I ett dynamiskt trafikscenario, där oförutsägbara anslutningsbegäranden inkommer och avslutas över tiden, så kommer fragmenteringen av spektrala resurser ha en betydande inverkan på nätverkets prestanda. I denna avhandling föreslås en ny algoritm för SPP i EONs för hantering av enskilda länkfel, där par av primära och sekundära vägar väljs gemensamt, vilket minimerar fragmentering och maximerar delning vilket leder till bättre nätverksprestanda i form av minskat blockering. Till skillnad från befintliga algoritmer beslutas den primära och sekundära vägen och spektrum samtidigt från en uppsättning av par av kandidatvägar och spektrumtilldelningen görs med en hybrid-kostnadsfunktion. Funktionen är en viktad kombination av befintliga mått som integrerar fragmentering och delning till en multi-objektiv målfunktion. Med användning av nätverkstrafiksimuleringar i två referensnätverk studeras effekten av olika kostnadsfunktioner på algoritmens beteende och en optimal uppsättning av vikter bestäms. Med dessa parametrar, trafiksimuleringar i en reducerad US-nätverkstopologi med belastningsvärden på 190-240 Erlang, motsvarande blockeringssannolikheter på 0,1 - 1%, visar en genomsnittlig förbättring under referensalgoritmen på 79% i blockeringens sannolikhet, 6.9% i delning och 5,9% i fragmentering. Det visas också att det mesta av denna förbättring beror på det samtidiga tilldelning av primära och reservlänkar. Hybridkostnadsfunktionen minskar blockeringen med ytterligare 10%.
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Karaer, Alican. "Effects of Traffic Incidents on Adjacent Facilities and Alternative Re-Routing Strategies." UNF Digital Commons, 2018. https://digitalcommons.unf.edu/etd/781.
Повний текст джерелаАнотація:
This study presents an analysis of detour operations as a concept of congestion management. Since a large portion of traffic delay emanates from traffic incidents, the goal of the study was to alleviate incident-induced impacts on freeways by diverting congested traffic on to adjacent roadway facilities. To balance the demand between freeway and arterial systems, optimization was required through Integrated Corridor Management (ICM). This thesis examines the justification and optimization of dynamic traffic routing strategies.
Previous studies have justified detour operations based solely on traffic simulation results. This study quantifies the impacts from freeway incidents on a parallel arterial roadway using a data-driven signal processing technique, with operating speeds adopted as a performance measure. Results show that rerouting traffic to an adjacent arterial road, due to a freeway incident, can mitigate the mobility of the corridor with a probability of up to 88% depending on the type of incident and occurrence time. Results also indicate that diverting traffic during off-peak hours, especially for minor incidents, provides minimal mobility benefits.
A secondary focus of this study explored the optimum dynamic traffic diversion, to an adjacent arterial roadway, from incident-induced freeway congestion to better utilize the freeway’s available corridor capacity. VISSIM, a microsimulation tool, was employed to simulate a freeway incident and measure the performance of detour operations. A 23 full factorial central composite design was used to establish a relationship between the performance of the detour operation and three control factors: incident duration, diversion rate, and demand level. The resulting regression equation predicts the corridor delay with over 83% accuracy. The findings of this study can potentially serve as a building block in the understanding and development of future ICM systems and incident management plans.
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Shek, Lai-yee Liza, and 石麗儀. "Ad Hoc routing and time-slot scheduling in bluetooth networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B29699393.
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Zhu, Lei. "Routing Map Topology Analysis and Application." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/347053.
Повний текст джерелаАнотація:
The transportation routing map is increasingly used in various transportation network modeling applications such as vehicle navigation and traffic assignment modeling. A typical navigation GIS map contains all detailed road facility layers and may not be as computationally efficient as a lower-resolution map for path finding. A lower-resolution transportation routing map retains only route-finding related roadways and is efficient for path finding but may result in sub-optimal routes because of misclassification links. With the goal in balancing the traffic analysis requirement of intended application and computation requirements of transportation navigation and traffic assignment, the systematic abstraction of the lower-resolution transportation routing map from high resolution map is an important and non-trivial task. For vehicle navigation applications, the traffic analysis requirement is the shortest path quality. An innovative transportation routing map abstraction method or Connectivity Enhancement Algorithm (CEA) is proposed to deal with vehicle navigation application routing map abstraction. The algorithm starts from a low-resolution network and keeps updating the map by adding links and nodes when it processes each search set. The outcome of the algorithm is an abstract map that retains the original detailed map's hierarchical structure with quality topological connectivity at a significant computations saving. With the development of traffic assignment modeling, a detailed network is desired to describe the real world traffic network. It is the consensus that one should not directly apply a GIS map blind-sight without a systematic approach and unnecessarily overuse the network details causes excessive run time. The traffic analysis requirement of those applications is the dynamic user equilibrium (DUE) condition network performance is identical or near-identical with high resolution network. The lowest network resolution level that meets the requirements of emerging traffic analysis is not easy to determine. The proposed traffic analysis network abstraction method gives a solution for this problem. It is an iterative network abstraction approach and considers the link travel time with DUE traffic condition. The case study and numerical analysis prove that the two network abstraction methods are sound and promising. The transportation routing map abstraction method could detect most misclassification links and is robust for different network scales. The abstracted navigation map provides the identical or near-identical SP cost/travel time for any OD pair while the computation burden is much lighter than that on original map. In another hand, the case studies about the traffic analysis network abstraction tell that the method converges very quick and the rendered the abstracted network that has lowest resolution of network or least links and nodes but the DUE condition network performance or trips cost/travel time is much closer to that on the original map.
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Muchanga, Americo Francisco. "Interdomain Traffic Engineering and Faster Restoration in Optical Networks." Doctoral thesis, KTH, Elektronik- och datorsystem, ECS, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4220.
Повний текст джерелаАнотація:
Internet traffic has surpassed voice traffic and is dominating in transmission networks. The Internet Protocol (IP) is now being used to encapsulate various kinds of services. The new services have different requirements than the initial type of traffic that was carried by the Internet network and IP. Interactive services such as voice and video require paths than can guarantee some bandwidth level, minimum delay and jitter. In addition service providers need to be able to improve the performance of their networks by having an ability to steer the traffic along the less congested links or paths, thus balancing the load in a uniform way as a mechanism to provide differentiated service quality. This needs to be provided not only within their domains but also along paths that might traverse more than one domain. For this to be possible changes have been proposed and some are being applied to provide quality of service (QoS) and traffic engineering (TE) within and between domains. Because data networks now carry critical data and there are new technologies that enable providers to carry huge amount of traffic, it is important to have mechanisms to safeguard against failures that can render the network unavailable. In this thesis we propose and develop mechanisms to enable interdomain traffic engineering as well as to speed up the restoration time in optical transport networks. We propose a mechanism, called abstracted path information, that enable peering entities to exchange just enough information to engage in QoS and TE operations without divulging all the information about the internal design of the network. We also extend BGP to carry the abstracted information. Our simulations show that BGP could still deliver the same performance with the abstracted information. In this thesis we also develop a method of classifying failures of links or paths. To improve the restoration time we propose that common failures be classified and assigned error type numbers and we develop a mechanism for interlayer communication and faster processing of signalling messages that are used to carry notification signals. Additionally we develop a mechanism of exchanging the failure information between layers through the use of service primitives; that way we can speed up the restoration process. Finally we simulate the developed mechanism for a 24 node Pan American optical transport network.QC 20100913
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Ehrenkranz, Toby, and Toby Ehrenkranz. "Ensuring a Valid Source and Destination for Internet Traffic." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12445.
Повний текст джерелаАнотація:
The Internet has become an indispensable resource for today's society. It is at the center of the today's business, entertainment, and social world. However, the core of our identities on the Internet, the IP addresses that are used to send and receive data throughout the Internet, are insecure. Attackers today are able to send data purporting to be from nearly any location (IP spoofing) and to reroute data destined for victims to the attackers themselves (IP prefix hijacking). Victims of these attacks may experience denial of service, misplaced blame, and theft of their traffic. These attacks are of the utmost importance since they affect the core layer of the Internet. Although the mechanisms of the attacks are different, they are essentially different sides of the same coin; spoofing attacks forge the identity of the sender, while hijacking attacks forge the identity of the receiver. They revolve around the same underlying lack of a secure identity on the Internet. This research reviews the existing state of the art IP spoofing and IP prefix hijacking research and proposes new defenses to close the missing gaps and provide a new level of security to our identities on the Internet.
This material is based upon work supported by the National Science Foundation under Grants No. CNS-0520326 and CNS-1118101. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
This dissertation includes both previously published/unpublished and co-authored material.
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Al-Momin, Mohammed M. Saeed Abdullah. "QoS-aware content oriented flow routing in optical computer network." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7670.
Повний текст джерелаАнотація:
In this thesis, one of the most important issues in the field of networks communication is tackled and addressed. This issue is represented by QoS, where the increasing demand on highquality applications together with the fast increase in the rates of Internet users have led to massive traffic being transmitted on the Internet. This thesis proposes new ideas to manage the flow of this huge traffic in a manner that contributes in improving the communication QoS. This can be achieved by replacing the conventional application-insensitive routing schemes by others which take into account the type of applications when making the routing decision. As a first contribution, the effect on the potential development in the quality of experience on the loading of Basra optical network has been investigated. Furthermore, the traffic due to each application was dealt with in different ways according to their delay and loss sensitivities. Load rate distributions over the various links due to the different applications were deployed to investigate the places of possible congestions in the network and the dominant applications that cause such congestions. In addition, OpenFlow and Optica Burst Switching (OBS) techniques were used to provide a wider range of network controllability and management. A centralised routing protocol that takes into account the available bandwidth, delay, and security as three important QoS parameters, when forwarding traffics of different types, was proposed and implemented using OMNeT++ networks simulator. As a novel idea, security has been incorporated in our QoS requirements by incorporating Oyster Optics Technology (OOT) to secure some of the optical links aiming to supply the network with some secure paths for those applications that have high privacy requirements. A particular type of traffic is to be routed according to the importance of these three QoS parameters for such a traffic type. The link utilisation, end to end delays and securities due to the different applications were recorded to prove the feasibility of our proposed system. In order to decrease the amount of traffic overhead, the same QoS constraints were implemented on a distributed Ant colony based routing. The traditional Ant routing protocol was improved by adopting the idea of Red-Green-Blue (RGB) pheromones routing to incorporate these QoS constraints. Improvements of 11% load balancing, and 9% security for private data was achieved compared to the conventional Ant routing techniques. In addition, this Ant based routing was utilised to propose an improved solution for the routing and wavelength assignment problem in the WDM optical computer networks.
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Grzybwska, Hanna. "Combination of vehicle routing models and dynamic traffic simulation for city logistics applications." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/125067.
Повний текст джерелаАнотація:
The urban network is a highly dynamic system. Thus, a modern and efficient fleet management in urban areas should account for dynamics of traffic conditions, variability in travel times, changes in demand and fleet availability. All these factors significantly affect the distribution of goods and the provision of services. As a consequence, the freight operations optimizing approaches should be based on the time-dependent travel time estimates rather than on the average static values commonly employed as input data.
Proficient dynamic fleet management decisions need to take into consideration all the factors conditioning the addressed problem. Hence, the customers’ requests and service conditions (demands, time windows, etc.), operational conditions of the employed fleet (vehicles’ availability, status, positions, current occupancy of the carriage space, etc.) and traffic conditions need to be reckoned with. This information can be provided in the real-time fashion and at an affordable price by the ICT applications and tools such as: ATIS, GPS, GPRS or other.
Instead of relying exclusively on the experience of a dispatcher, it is effective to base the freight management decisions on information provided by a professional Decision Support System facilitating the consideration of all the factors conditioning the addressed issue.
The objective of the present thesis is to propose, implement and computationally test, on the basis of a simulation, the architecture of a Decision Support System for real-time freight management able of accounting for all the dynamic factors mentioned above. Its design is based on integration of a selected pickup and delivery vehicle routing model and dynamic traffic simulation models, whose purpose is to carefully emulate the evolving traffic conditions. The optimal dynamic routing and scheduling of a vehicle fleet is obtained due to dynamic modifications of the current routing and scheduling plan on the basis of the recently revealed information conditioning the addressed problem. The obtained results of computational experiments show that the performance of freight fleet strongly depends on the traffic information used to create the routing and scheduling plan. Due to the special character of transport operations performed in metropolitan areas it is possible that not all the scheduled customers would be served, although a feasible initial solution is created on the basis of the historical travel times’ data.
Hence, there is a need to implement real-time rerouting strategies allowing modifications of the original routes in order to feasibly fulfil the routing tasks. In addition, the tighter the constraints specifying the customers’ time windows and the higher the number of dynamically appearing requests, the higher the cost of the performance and the level of utilization of the freight fleet.La red urbana es un sistema altamente dinámico. Por lo tanto, la gestión moderna y eficiente de la flota en las zonas urbanas debe tener en cuenta la dinámica de las condiciones del tráfico, la variabilidad en los tiempos de viaje y los cambios en la disponibilidad de la demanda y de la flota, ya que afectan de manera significativa en la distribución de bienes y la prestación de servicios. Como consecuencia, los enfoques para optimizar las operaciones de carga deben basarse en las estimaciones de los tiempos de viaje dependientes del tiempo y no en los valores medios estáticos comúnmente empleados como datos de entrada. Las decisiones competentes de gestión dinámica de las flotas necesitan tener en cuenta todos los factores que condicionan el problema abordado. Por lo tanto, hay que considerar las características de las peticiones y las condiciones de servicio de los clientes (demanda, ventanas de tiempo, etc.), las condiciones operacionales de la flota empleada (disponibilidad de los vehículos, estatus, ubicación, ocupación actual del espacio de transporte, etc.) y las condiciones de tráfico. Esta información puede ser proporcionada en tiempo real a un precio asequible por las aplicaciones de las TIC y herramientas tales como: ATIS, GPS, GPRS u otros. En lugar de confiar exclusivamente en la experiencia de un distribuidor, también sería correcto basar las decisiones de gestión de transporte de mercancías en la información proporcionada por un sistema profesional de apoyo a la toma de decisiones que facilita la consideración de todos los factores que condicionan el problema abordado. El objetivo de esta tesis es proponer, implementar y validar computacionalmente en base a la simulación, la arquitectura de un Sistema de Apoyo a la Toma de Decisiones para la gestión de transporte de mercancías en tiempo real capaz de considerar todos los factores dinámicos previamente mencionados. Su diseño se basa en la integración de un modelo seleccionado de rutas de vehículos con recogida y entrega y modelos de simulación de tráfico dinámicos cuyo propósito es emular detalladamente las condiciones de tráfico que cambian con el paso del tiempo. Las rutas y los horarios dinámicos óptimos para una flota de vehículos que transporta mercancías se obtienen de las modificaciones dinámicas de un plan actual de rutas y horarios en base a la nueva información recibida que condiciona el problema abordado. Los resultados obtenidos de los experimentos computacionales demuestran que el rendimiento de la flota de transporte de mercancías depende en gran medida de la información de tráfico utilizada para crear el plan de rutas y los horarios. Debido al carácter especial de las operaciones de transporte realizadas en las áreas metropolitanas, a pesar de una solución inicial factible que se crea sobre la base de los datos históricos de los tiempos de viaje, es posible que no todos los clientes sean servidos. Por lo tanto, hay una necesidad de implementar estrategias de cambios de rutas en tiempo real, que permiten modificar las rutas originales con el fin de cumplir las tareas de enrutamiento viables. Además, más estrictas son las limitaciones que especifican las ventanas del tiempo de los clientes y más alto es el número de solicitudes de servicio que aparecen de forma dinámica, mayor será el coste final de las prestaciones del servicio y el nivel de utilización de la flota de transporte de mercancías.
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Kim, Minseok. "A heuristic for routing hazmat transport given real-time weather and traffic information." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3530.
Повний текст джерелаАнотація:
Thesis (M.S.) -- University of Maryland, College Park, 2006.Thesis research directed by: Dept. of Civil and Environmental Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Khajuriwala, Burhanuddin F. "Dynamic adaptive routing for traffic management and fault tolerance in high speed networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0015/MQ49383.pdf.
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Kayahan, Hüseyin. "Treatment Framework : Traffic Steering via Source-Routing in SDN for Service Function Chaining." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-247926.
Повний текст джерелаАнотація:
The middlebox architecture is long known for its inharmonious presence within the Internet architecture. Network functions realized in middleboxes are inclined to interpose end to end connections, modifying the datagram header or spawning new connections on behalf, which renders policy enforcement challenging. Moreover, their tight coupling with metadata makes its distributed persistence difficult, which hampers the flexible utilization and scalable provisioning of the middlebox infrastructure resources under varying loads. Existing attempts at mitigating these problems include middlebox placement, packet tagging and metadata migration; each solving only a part of the problem.Investing in the extensible nature of IPv6, the Treatment Framework (TRF) exploits source routing with the flavor of a discretionarily classifiable address space. Datagrams traverse the treatment domain with an extension header pushed and popped at the domain’s edges, for which forwarding takes place based on the information encoded within. The forwarding mechanics that leverage SDN consists of one match and three OpenFlow actions implementation, whereby TRF obviates the need for an underlying transport. Customizable address space allows providers to tailor routing aggregation to their middlebox farms topology, reducing the number of flow rules in the core to preinstallable sizes.Middleboxes in a treatment domain match traffic to the respective local policy based on the information encoded in the extension header. Extension headers are native to IPv6 and defined by standards, hence the middlebox modification problem is addressed without requiring alteration nor visibility into proprietary code. The framework resolves the policy enforcement problem altogether and allows asymmetric service chaining. While eliminating the flow setup time in the core, the framework’s footprint at ingress that push the extension header can get heavy with respect to flow churn rate.Det har länge varit känt att arkitektur baserad på mellanliggande utrustning, s.k.middlebox-arkitektur, inte alltid rimmar väl med Internet i övrigt. Nätverksfunktioner som implmenteras i middleboxar tenderar att leda till olika typer av förbindelser, modifierande av pakethuvuden eller nya uppkopplingar, vilket medför att det blir utmanande att verkställa olika typer av policy. Middlebox-lösningar är dessutom tätt kopplade till olika typer av metadata vilket innebär svårigheter för dess distribuerade fortlevnad och hindrar ett flexibelt utnyttjande och skalbar utbyggnad middleboxresurser under varierande trafiklast. Befintliga försök att mildra sådana problem inkluderar placering av mellanliggande utrustning, paketmärkning och migration av metadata; vart och ett av dessa löser endast delar av problemet.TRF (Treatment Framework) drar nytta av den utbyggbarhet som finns i IPv6 och använder vägval som styrs helt från avsändaren tillsammans med diskretionär adressrymd. IP-paketen traverserar en behandlings-domän och ett utökat pakethuvud används inom domänen. Det utökade pakethuvudet läggs till när paketet är på väg in i domänen och tas bort när paketet lämnar domänen. Inom domänen används information i det utökade pakethuvudet för att styra vidarebefordringen av paketet. Mekanismerna för vidarebefordring av paket använder sig av SDN och består av en match-operation och tre OpenFlow-åtgärder, varmed TRF kringgår behov av en underliggande transport. En anpass-ningsbart adressrymd gör det möjligt för leverantörer att skräddarsy vägvalsaggregering till sin middlebox-lösning, vilket gör att antalet trafikregler i kärnan av deras nät kan reduceras till förinställbara storlekar.En middlebox-lösning i en behandlings-domän matchar trafik mot respektive lokal policy baserad på information kodad i det utökade pakethuvudet. Tekniken med utökat pakethuvud är inbyggd i IPv6 och standardiserad vilket göra att paketmodifiering i en middlebox kan adresseras utan att kräva ändringar eller insyn i proprietär programvara. Ramverket löser problemet med verkställa olika typer av policy i sin helhet och medger skapandet av assymtriska kedjor av paketbehandlingstjänster. Tiden för att sätta upp paketflöden i kärnan av nätet kan elimineras, men det fotavtryck som ramverket ger i ingressdelen av domänen, där det utökade pakethuvudet skapas och läggs till inkommand paket, kan bli betydande med avseende på flödeshastigheten.
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Gao, Song 1976. "Routing problems in stochastic time-dependent networks with applications in dynamic traffic assignment." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8310.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.Includes bibliographical references (p. 155-157).
Stochasticity is prevalent in transportation networks in general, and traffic networks in particular. The overall objective of this thesis is to study implications and significance of stochasticity in the development of models and algorithms for dynamic traffic flows in road networks. There are two major parts in this thesis. We first study the best routing policy problems in stochastic and time-dependent networks, and then develop policy-based stochastic dynamic traffic assignment models and algorithms. Routing problems are not only useful to develop dynamic traffic assignment (DTA) methods, but are also fundamental network optimization problems with a wider application domain. We define the problem in general and give a framework, which we believe is the first in the literature. We give a comprehensive taxonomy and an indepth discussion of most of the variants of the problem. We study in detail a variant pertinent to the traffic in road networks. We give an exact solution algorithm to this variant, analyze its running time complexity and point out the importance of finding good approximation algorithms. We then present several approximations, and study their effectiveness against the exact algorithm, both theoretically and computationally. We proceed to develop a policy-based stochastic dynamic traffic assignment model. We give a conceptual framework and then develop models for users' choice of policies and the dynamic network loading problem. These models are two major components of the overall DTA model. We give solution algorithms for these models, and present a heuristic algorithm to solve the proposed policy-based DTA model. Using an example, we show that policy-based DTA models have solutions that are different in expected travel times than the path-based models.
by Song Gao.
S.M.
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MAHAPATRA, ABINASH. "QOS AND ENERGY AWARE ROUTING FOR REAL TIME TRAFFIC IN WIRELESS SENSOR NETWORKS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1070555178.
Повний текст джерела
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Kolar, Vinay. "Routing and traffic-engineering in multi-hop wireless networks an optimization based approach /." Diss., Online access via UMI:, 2007.
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胡玉蓉 and Yurong Hu. "Datagram routing for low earth orbit satellite networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31224441.
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Heidari, Fariba. "Quality of service routing using decentralized learning." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115672.
Повний текст джерелаАнотація:
This thesis presents several decentralized, learning-based algorithms for on-line routing of bandwidth guaranteed paths. The presented routing algorithms do not need any a-priori knowledge of traffic demand; they use only their locally observed events and update their routing policy using learning schemes. The employed learning algorithms are either learning automata or the multi-armed bandit algorithms. We investigate the asymptotic behavior of the proposed routing algorithms and prove the convergence of one of them to the user equilibrium. Discrete event simulation results show the merit of these algorithms in terms of improving the resource utilization and increasing the network admissibility compared with shortest path routing.We investigate the performance degradation due to decentralized routing as opposed to centralized optimal routing policies in practical scenarios. The system optimal and the Nash bargaining solutions are two centralized benchmarks used in this study. We provide nonlinear programming formulations of these problems along with a distributed recursive approach to compute the solutions. An on-line partially-decentralized control architecture is also proposed to achieve the system optimal and the Nash bargaining solution performances. Numerical results in some practical scenarios with well engineered networks, where the network resources and traffic demand are well matched, indicate that decentralized learning techniques provide efficient, stable and scalable approaches for routing the bandwidth guaranteed paths.
In the context of on-line learning, we propose a new algorithm to track the best action-selection policy when it abruptly changes over time. The proposed algorithm employs change detection mechanisms to detect the sudden changes and restarts the learning process on the detection of an abrupt change. The performance analysis of this study reveals that when all the changes are detectable by the change detection mechanism, the proposed tracking the best action-selection policy algorithm is rate optimal. On-line routing of bandwidth guaranteed paths with the potential occurrence of network shocks such as significant changes in the traffic demand is one of the applications of the devised algorithm. Simulation results show the merit of the proposed algorithm in tracking the optimal routing policy when it abruptly changes.
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Sawant, Uttara. "Grid-based Coordinated Routing in Wireless Sensor Networks." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5437/.
Повний текст джерелаАнотація:
Wireless sensor networks are battery-powered ad-hoc networks in which sensor nodes that are scattered over a region connect to each other and form multi-hop networks. These nodes are equipped with sensors such as temperature sensors, pressure sensors, and light sensors and can be queried to get the corresponding values for analysis. However, since they are battery operated, care has to be taken so that these nodes use energy efficiently. One of the areas in sensor networks where an energy analysis can be done is routing. This work explores grid-based coordinated routing in wireless sensor networks and compares the energy available in the network over time for different grid sizes.
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Kammenhuber, Nils [Verfasser]. "Traffic-adaptive routing / Nils Kammenhuber." 2008. http://d-nb.info/991745469/34.
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Cho, Woon Hyung. "TIDR traffic-aware inter-domain routing /." 2007. http://etd.lib.fsu.edu/theses/available/etd-07092007-213717.
Повний текст джерелаАнотація:
Thesis (M.S.)--Florida State University, 2007.Advisor: Zhenhai Duan, Florida State University, College of Arts and Sciences, Dept. of Computer Science. Title and description from dissertation home page (viewed Oct. 8, 2007). Document formatted into pages; contains vii, 25 pages. Includes bibliographical references.
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Chang, Hsien-Cheng, and 張晛承. "Exploiting Traffic Patterns for Real-Time Traffic Prediction and Vehicle Routing." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/58543183899669637088.
Повний текст джерелаАнотація:
碩士國立清華大學
資訊工程學系
101
Real-time traffic prediction is a fundamental capability of reducing traffic congestion and improving traffic mobility. Recently, the traffic information in the urban area of the Taipei city is available from Institute of Transportation, Ministry of Transportation and Communications, Taiwan. Given this information, it is possible to analyze and extract some traffic patterns. In this paper, we use these patterns to design a semi-parametric prediction model which provides an efficient mean to estimate accurately the future traffic conditions. Furthermore, we propose a novel vehicle routing algorithm which can plan routes with less delay for the drivers. The vehicle routing algorithm is composed of our proposed prediction model and the existing shortest path algorithm. Finally, in the performance evaluation, we show the capability of our methodology to predict future traffic conditions accurately and to enable the drivers to arrive the destinations within less time.
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Chen, Yun-Wen, and 陳韻文. "QoS Routing Algorithms for Multiple Traffic Classes." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/06201570684456489166.
Повний текст джерелаАнотація:
碩士國立中正大學
資訊工程研究所
88
One of the most important features of the next generation Internet is the ability to provide quality of service (QOS) guarantee. Recent developments in Internet provide at least two types of service. For example, guaranteed service and controlled load service in Integrated services networks, and expedited forwarding and assured forwarding in Differentiated services networks. Providing guaranteed service and expedited service, referred to as bandwidth-guaranteed traffic, requires reservation of a fixed amount of bandwidth while controlled load service and assured forwarding service, referred to as fair-shared traffic, requires reservation of a minimum amount of bandwidth to ensure finite queue length. Routing in a network with these two types of service should take their traffic and QOS characteristics into consideration. In this paper, we propose three routing algorithms that use different cost functions and routing strategies when routing different class of traffic. Our simulation results show that the proposed algorithms are able to yield low blocking probability for bandwidth-guaranteed traffic and high max-min fair share rate for fair-shared traffic under various traffic conditions.
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洪夢麟. "Finding Link Disjoint Routing Paths Based on Traffic Intensity for Alternate Routing." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/27775067472401303114.
Повний текст джерелаАнотація:
碩士國立清華大學
資訊工程學系
95
An alternate routing algorithm requires a set of predetermined routing paths for each sourcedestination pair. To reduce the connection blocking probability, it is desirable that the predetermined routing paths between each source-destination pair be link-disjoint. The predetermined routing paths used in previous works on alternate routing are the k-shortest paths in terms of hop count. However, depending on the traffic requirements of all source-destination pairs, hop count based k-shortest paths may not be the best choice for the predetermined routing paths. This thesis proposes a method to find a set of link-disjoint routing paths for each sourcedestination pair to be used by an alternate routing algorithm in order to reduce the connection blocking probability. The key idea is to utilize the routing paths that are used by the optimal traffic pattern in the network. Then, for each source-destination pair, we select a set of link-disjoint routing paths from the routing paths that are used by the optimal traffic pattern such that the selected set of link-disjoint routing paths carries the most of the traffic between the source-destination pair. Simulations are performed to compare the performance of two alternate routing algorithms that use the link-disjoint routing paths found by the proposed method as the predetermined routing paths and those of the same alternate routing algorithms that employ the hop count based k-shortest link-disjoint paths as the predetermined routing paths. Our simulation results show that using the link-disjoint routing paths found by the proposed method yields significantly lower connection blocking probability than employing the hop count based k-shortest link-disjoint paths.