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Showing papers on "Network traffic simulation published in 2007"


Patent
03 Jul 2007
TL;DR: In this article, a method of testing a digital mobile phone network such as a GPRS or 3G network comprises either using real traffic or creating test traffic using test mobile phone coupled to a computer, and using the computer to measure a parameter associated with the network's response to the traffic.
Abstract: A method of testing a digital mobile phone network such as a GPRS or 3G network comprises either using real traffic or creating test traffic using test mobile phone coupled to a computer, and using the computer to measure a parameter associated with the network's response to the traffic. The measurements made by the computer are themselves sent as traffic to create one or more data streams within the mobile phone network comprising the traffic, measurements relating to the traffic, and signalling relating to the traffic, whereby this data stream or these streams can be captured at interface points within the network and analysed to investigate the functioning of the network dynamically as the network is exercised with the traffic. Software and test equipment for performing the method are also described.

152 citations


Patent
23 Aug 2007
TL;DR: In this article, a power usage policy is automatically enforced by the network device based on historical traffic patterns and is dynamically adjusted over time based on network traffic statistics for traffic flowing through a network device.
Abstract: Particular embodiments provide power usage management for network devices according to historical traffic pattern data. Network traffic statistics for traffic flowing through a network device may be determined. A traffic pattern for a time period based on the traffic flowing through the network device is then determined. The network device may then manage power based on the pattern. For example, when a pattern indicates that traffic flowing through the network device is light during a time period, then the network device may operate in a lower power mode, such as a standby mode and when it indicates that there is higher usage, the network device may operate in a normal power mode. In one embodiment, a power usage policy may be determined based on the historical traffic patterns and is automatically enforced by the network device. The power usage policy may also be dynamically adjusted over time based on network traffic statistics.

129 citations


Journal ArticleDOI
TL;DR: A mathematical framework and a solution approach are presented for the simultaneous calibration of the demand and supply parameters and inputs to microscopic traffic simulation models as well as a large-scale application emphasizing practical issues.
Abstract: A mathematical framework and a solution approach are presented for the simultaneous calibration of the demand and supply parameters and inputs to microscopic traffic simulation models as well as a large-scale application emphasizing practical issues. Microscopic traffic simulation models provide detailed estimates of evolving network conditions by modeling time-varying demand patterns and individual drivers' detailed behavioral decisions. Such models are composed of elements that simulate different demand and supply processes and their complex interactions. Several model inputs (such as origin-destination flows) and parameters (car-following and lane-changing coefficients) must be specified before these simulation tools can be applied, and their values must be determined so that the simulation output accurately replicates the reality reflected in traffic measurements. A methodology is presented here for simultaneously estimating all microscopic simulation model parameters by using general traffic measurements. A large-scale case study for the calibration of the MITSimLab microscopic traffic simulation model by using the network of Lower Westchester County, New York, is employed to demonstrate the feasibility, application, and benefits of the proposed methodology.

122 citations


Journal ArticleDOI
TL;DR: It is proved that both stability and optimality of the joint system can be guaranteed for sufficiently elastic traffic simply by tuning the cost function used for traffic engineering.
Abstract: In the Internet today, traffic engineering is performed assuming that the offered traffic is inelastic. In reality, end hosts adapt their sending rates to network congestion, and network operators adapt the routing to the measured traffic. This raises the question of whether the joint system of congestion control (transport layer) and routing (network layer) is stable and optimal. Using the established optimization models for TCP and traffic engineering as a basis, we find the joint system can be stabilized and often maximizes aggregate user utility. We prove that both stability and optimality of the joint system can be guaranteed for sufficiently elastic traffic simply by tuning the cost function used for traffic engineering. Then, we present a new algorithm that adapts on a smaller timescale to changes in traffic distribution and is more robust to large traffic bursts. Uniting the network and transport layers in a multi-layer approach, this algorithm, distributed adaptive traffic engineering (DATE), jointly optimizes the goals of end users and network operators and reacts quickly to avoid bottlenecks. Simulations demonstrate that DATE converges quickly

115 citations


Proceedings ArticleDOI
27 Jun 2007
TL;DR: The eye-in-the-sky alternative to collecting real-time temporal/spatial data using small unmanned helicopters is proposed to monitor traffic, evaluate and assess traffic patterns and provide accurate vehicle counts.
Abstract: The eye-in-the-sky alternative to collecting real-time temporal/spatial data using small unmanned helicopters is proposed to: monitor traffic, evaluate and assess traffic patterns and provide accurate vehicle counts. Collected real-time visual data are converted to traffic statistical profiles and used as continuously updated inputs to existing traffic simulation models improving calibration, accuracy (in terms of variable parameter values) and future traffic predictions. Functionality of simulation models is enhanced, and reliability is improved The proposed approach offers significant advantages over conventional methods where historical and outdated data is used to run poorly calibrated traffic simulation models.

113 citations


Patent
25 Jul 2007
TL;DR: In this article, the authors present a real-time, synchronized simulation system for process control systems, which includes a simulation process control network and a process model which are automatically updated periodically during the operation of the actual control network to reflect changes made to the process control system, as well as to account for changes in the plant itself.
Abstract: A process control system simulation technique performs real-time simulation of an actual process control network as that network is running within a process plant in a manner that is synchronized with the operation of the actual process control network. This real-time, synchronized simulation system includes a simulation process control network and a process model which are automatically updated periodically during the operation of the actual process control network to reflect changes made to the process control network, as well as to account for changes in the plant itself i.e., changes which require an updated process model. The disclosed simulation system provides for more readily accessible and usable simulation activities, as the process control network and the process models used within the simulation system are synchronized with and up-to-date with respect to the current process operating conditions. Moreover, this simulation system is more accurate as it uses process models developed from the current state of the process whenever the simulation system beings to perform a simulation. Still further, the disclosed simulation system is easy to operate, as it uses the same user interface applications as the actual process control network and can be initialized and used at any time during operation the process plant without any significant configuration or set-up activities.

88 citations


Proceedings ArticleDOI
10 Sep 2007
TL;DR: A hybrid simulation approach is proposed that can significantly reduce the number of scheduled events by making use of statistical models and is demonstrated in a first application study where a speed funnel is built using inter-vehicle communications.
Abstract: To study the impact of inter-vehicle communications on (vehicular) transport efficiency, e.g., for traffic management purposes, there is a need for efficient and accurate large-scale simulations that jointly consider both, the vehicular traffic and the communication system. To overcome the scalability limitations of current discrete event-based network simulators like NS-2, we propose a hybrid simulation approach that can significantly reduce the number of scheduled events by making use of statistical models. Basically, we treat some data traffic, which is not the primary concern of the simulation study, as 'noise' (e.g., beaconing of nodes). While accurately modeling this background traffic we only need to simulate via discrete event-based simulation the actual application we are interested in (e.g., a data dissemination protocol). We outline how the characterization of the background traffic is gained, statistically validated and used. The achievable speed-up is demonstrated in a first application study where a speed funnel is built using inter-vehicle communications. In this scenario, the conservatively estimated speed-up factor is about 500 compared to a pure discrete event-based simulation.

88 citations


Posted Content
TL;DR: The first network performance measure that can be used to assess the efficiency of a network in the case of either fixed or elastic demands is proposed and allows one to determine the criticality of various nodes (as well as links) through the identification of their importance and ranking.
Abstract: In this paper, we propose the first network performance measure that can be used to assess the efficiency of a network in the case of either fixed or elastic demands. Such a measure is needed for many different applications since only when the performance of a network can be quantifiably measured can the network be appropriately managed. Moreover, as we demonstrate, the proposed performance measure, which captures flow information and behavior, allows one to determine the criticality of various nodes (as well as links) through the identification of their importance and ranking. We present specific networks for which the performance/efficiency is computed along with the importance rankings of the nodes and links. The new measure can be applied to transportation networks, supply chains, financial networks, electric power generation and distribution networks as well as to the Internet and can be used to assess the vulnerability of a network to disruptions.

75 citations


Journal ArticleDOI
TL;DR: This paper focuses on how to combine the kernel re-entering and discrete-event simulation methodologies to execute simulations quickly and the performance and scalability of NCTUns.

63 citations


Journal ArticleDOI
TL;DR: Simulation results show that the degree distribution of the networks constructed in synchronized flow has two power law regions, so the distinction in topological structure can really reflect the different dynamics in traffic flow.
Abstract: Complex networks are constructed in the evolution process of traffic flow, and the states of traffic flow are represented by nodes in the network. The traffic dynamics can then be studied by investigating the statistical properties of those networks. According to Kerner's three-phase theory, there are two different phases in congested traffic, synchronized flow and wide moving jam. In the framework of this theory, we study different properties of synchronized flow and moving jam in relation to complex network. Scale-free network is constructed in stop-and-go traffic, i.e., a sequence of moving jams [Chin. Phys. Lett. 10, 2711 (2005)]. In this work, the networks generated in synchronized flow are investigated in detail. Simulation results show that the degree distribution of the networks constructed in synchronized flow has two power law regions, so the distinction in topological structure can really reflect the different dynamics in traffic flow. Furthermore, the real traffic data are investigated by this method, and the results are consistent with the simulations.

59 citations


01 Jan 2007
TL;DR: Wireless and mobile networks present substantial challenges in the validation of large-scale network models and simulation, even beyond the already difficult problem of validation in more conventional wired and stationary networks.
Abstract: Wireless and mobile networks present substantial challenges in the validation of large-scale network models and simulation, even beyond the already difficult problem of validation in more conventional wired and stationary networks. These additional challenges are due to the complications and subtleties of physical movement and wireless propagation, making the system highly variable and substantially increasing the complex interactions between the parts of the system and the surrounding environment. These same factors also make wireless and mobile experiments in the real world not easily or accurately repeatable, reducing the use of such experiments for validation. In particular, the position and movement of nodes in the network can have a significant effect on the behavior and performance of the system being modeled. The position and possible movement of other objects in the environment around the nodes themselves, such as buildings, hills, and trees, or vehicles, people, and rain, can also significantly effect the system being modeled. Furthermore, to accurately control an entire experiment in the real world, all of these positions and movements would need to be controlled to within a fraction of a wavelength of the radios involved, due to differences in the radio multipath environment even such small position differences can cause. Having complete control over all of these factors is simply not fully achievable in any real system, and so models and real experiments, to some degree, can only be approximations.

Patent
12 Jun 2007
TL;DR: In this article, a distributed mediation network and method of employing such is provided, having a plurality of different types of network module, each module has a non-reciprocal path therethrough for network traffic and the distribution of network traffic across the network is managed by an autonomic control plane.
Abstract: A distributed mediation network and method of employing such is provided, having a plurality of different types of network module. Each module has a non-reciprocal path therethrough for network traffic and the distribution of network traffic across the network is managed by an autonomic control plane.

Journal ArticleDOI
TL;DR: Typical data sets are given and the network architecture and traffic specifications that generated the multifractal traffic are described in detail.

Proceedings ArticleDOI
01 Oct 2007
TL;DR: An extensive analysis of the gains of network coding as compared to traditional transmission strategies in a single-hop setting is provided, and it is shown that the gains are significant in general and can be considerably large in some cases.
Abstract: We study the scaling law governing the delay gains of network coding as compared to traditional transmission strategies in unreliable wireless networks. We distinguish between two types of traffic, namely elastic and inelastic, where the elasticity of a flow is based on the delay constraints associated with it. This novel formulation is useful in that it allows for the modeling of real-time traffic more accurately. Considering the limited availability of feedback in such systems, we focus on strategies with minimal acknowledgement requirements. Under both traffic types, we provide an extensive analysis of the gains of network coding as compared to traditional transmission strategies in a single-hop setting, and show that the gains are significant in general and can be considerably large in some cases. We further provide a method for realizing these gains in multi-hop networks with general topologies using the analysis of the single hop scenario.

Proceedings ArticleDOI
11 May 2007
TL;DR: This work developed an integrated traffic/network simulation tool for evaluating network protocols in realistic VANET environments and employed well-studied microsimulation models and wireless ad hoc network models from the domain of transportation and traffic science and the networking community.
Abstract: Simulation of network protocol behavior in Vehicular Ad Hoc Network (VANET) scenarios is the predominant basis for evaluating the applicability of particular protocols developed in the Mobile Ad Hoc Network (MANET) domain. As the selection of a mobility model influences the outcome of simulations to a great deal, the use of a representative model is necessary for producing meaningful evaluation results. In this work, we discuss and motivate the needs for coupling traffic micro simulation with standard network simulation. In particular, we developed such an integrated traffic/network simulation tool for evaluating network protocols in realistic VANET environments. In our work, we employed well-studied microsimulation models and wireless ad hoc network models from the domain of transportation and traffic science and the networking community, respectively. It could be shown that network simulations that make use of realistic traffic models produce vastly different results than those relying on commonly used simplistic models, while their adoption incurs only negligible performance penalties.

Journal ArticleDOI
TL;DR: A simplified game theory model is proposed for simulating the evolution of the traffic network, where three network manipulators, passengers, an urban public traffic company, and a government traffic management agency play games in a network evolution process.
Abstract: We have studied urban public traffic networks from the viewpoint of complex networks and game theory. Firstly, we have empirically investigated an urban public traffic network in Beijing in 2003, and obtained its statistical properties. Then a simplified game theory model is proposed for simulating the evolution of the traffic network. The basic idea is that three network manipulators, passengers, an urban public traffic company, and a government traffic management agency, play games in a network evolution process. Each manipulator tries to build the traffic lines to magnify its “benefit”. Simulation results show a good qualitative agreement with the empirical results.

Proceedings ArticleDOI
01 May 2007
TL;DR: A software infrastructure that embeds physical hosts in a simulated network that is flexible, secure, and scalable-attributes inherited directly from the VPN implementation, and conducted a set of preliminary experiments to assess the performance limitations of the emulation infrastructure.
Abstract: We present a software infrastructure that embeds physical hosts in a simulated network. Aiming to create a large-scale real-time virtual network testbed, our real-time interactive simulation approach combines the advantages of both simulation and emulation, by maintaining flexibility of the simulation models and increasing fidelity as real systems are included in the simulation. In our approach, real-world distributed applications and network services can run together with the real-time simulator; real packets are injected into the simulation and subject to the simulated network conditions computed as a result of both real and virtual traffic competing for network resources. A prototype of the proposed emulation infrastructure has been implemented based on virtual private network (VPN). One distinct advantage of our approach is that it does not require special hardware. Furthermore, it is flexible, secure, and scalable-attributes inherited directly from the VPN implementation. We conducted a set of preliminary experiments to assess the performance limitations of our emulation infrastructure. We also present an interesting case study to demonstrate the capability of our approach.

Journal ArticleDOI
TL;DR: A new transportation network efficiency measure that can be used to assess the performance of a transportation network and which differs from other proposed measures, including complex network measures, in that it captures flows, costs, and travel behavior information, along with the topology.
Abstract: In this paper, we propose a transportation network efficiency measure that can be used to assess the performance of a transportation network and which differs from other proposed measures, including complex network measures, in that it captures flows, costs, and travel behavior information, along with the topology. The new transportation network efficiency measure allows one to determine the criticality of various nodes (as well as links) as we demonstrate through a network component importance definition, which is well-defined even if the network becomes disconnected. Several illustrative transportation network examples are provided in which the efficiencies and importance of network components are explicitly computed, and their rankings tabulated. This framework can be utilized to assess the vulnerability of network components in terms of their criticality to network efficiency/performance and to, ultimately, enhance security.

Patent
30 Mar 2007
TL;DR: In this paper, a traffic manager may monitor network performance, detect that the network performance has changed, and may prioritize network traffic based on which application or function is associated with the traffic.
Abstract: A traffic manager may monitor network performance, detect that the network performance has changed, and may prioritize network traffic based on which application or function is associated with the traffic. Each packet of network traffic may be analyzed to determine a source application or source function and allowed or disallowed along the network based on a set of predetermined priorities. Several sets of priorities may be established for various network performance conditions. In some embodiments, traffic may be routed along different paths using the sets of priorities and the source application or function. The traffic manager is adaptable for web-based services, applications, or other functions provided over a network connection.

Journal ArticleDOI
TL;DR: The reported results indicate that the generator based on multiplexing strictly alternating ON/off sources may perform better than generators based on chaotic maps, provided that more than 100 ON/OFF sources can be used.

Proceedings ArticleDOI
14 Mar 2007
TL;DR: DiSenS (DIstributed SENsor network Simulation) is introduced -- a highly scalable distributed simulation system for sensor networks that achieves greater scalability than even many discrete event simulators.
Abstract: Simulation is widely used for developing, evaluating and analyzing sensor network applications, especially when deploying a large scale sensor network remains expensive and labor intensive. However, due to its computation intensive nature, existent simulation tools have to make trade-offs between fidelity and scalability and thus offer limited capabilities as design and analysis tools. In this paper, we introduce DiSenS (DIstributed SENsor network Simulation) -- a highly scalable distributed simulation system for sensor networks. DiSenS does not only faithfully emulates an extensive set of sensor hardware and supports extensible radio/power models, so that sensor network applications can be simulated transparently with high fidelity, but also employs distributed-memory parallel cluster system to attack the complex simulation problem. Combining an efficient distributed synchronization protocol and a sophisticated node partitioning algorithm (based on existent research), DiSenS achieves greater scalability than even many discrete event simulators. On a small to medium size cluster (16-64 nodes), DiSenS is able to simulate hundreds of motes in realtime speed and scale to thousands in sub-realtime speed. To our knowledge, DiSenS is the first full-system sensor network simulator with such scalability.

Patent
10 Oct 2007
TL;DR: In this article, a system and method for dynamic network traffic prioritization is presented, which can include the operation of offering a plurality of prioritization options to a user on a network.
Abstract: A system and method are provided for dynamic network traffic prioritization. The method can include the operation of offering a plurality of network traffic prioritization options to a user on a network. A user selected network traffic prioritization option can be communicated to a network configuration device through the network. Another operation is using the network configuration device to configure a plurality of networking devices dynamically. This can provide network prioritization through the network based on the user's selected network traffic prioritizations.

Proceedings Article
17 Jun 2007
TL;DR: The design and evaluation of a system that can shed excess load in the presence of extreme traffic conditions, while maintaining the accuracy of the traffic queries within acceptable levels are presented.
Abstract: Monitoring and mining real-time network data streams is crucial for managing and operating data networks. The information that network operators desire to extract from the network traffic is of different size, granularity and accuracy depending on the measurement task (e.g., relevant data for capacity planning and intrusion detection are very different). To satisfy these different demands, a new class of monitoring systems is emerging to handle multiple arbitrary and continuous traffic queries. Such systems must cope with the effects of overload situations due to the large volumes, high data rates and bursty nature of the network traffic. In this paper, we present the design and evaluation of a system that can shed excess load in the presence of extreme traffic conditions, while maintaining the accuracy of the traffic queries within acceptable levels. The main novelty of our approach is that it is able to operate without explicit knowledge of the traffic queries. Instead, it extracts a set of features from the traffic streams to build an on-line predictionmodel of the query resource requirements. This way the monitoring system preserves a high degree of flexibility, increasing the range of applications and network scenarios where it can be used. We implemented our scheme in an existing network monitoring system and deployed it in a research ISP network. Our results show that the system predicts the resources required to run each traffic query with errors below 5%, and that it can efficiently handle extreme load situations, preventing uncontrolled packet losses, with minimum impact on the accuracy of the queries' results.

Patent
11 Oct 2007
TL;DR: In this paper, a policy-based network flow management system and method is presented, where various policy conditions are configured based at least in part upon source network conditions and multi-layer information associated with network traffic.
Abstract: A policy-based network flow management system and method. In one embodiment, various policy conditions are configured based at least in part upon source network conditions and multi-layer information (e.g., Layer 2, Layer 3, and so on) associated with network traffic. Where network traffic from a content requester is determined to satisfy a policy condition, a corresponding policy action is effectuated, e.g., dropping the network traffic, forwarding the network traffic, redirecting the network traffic, or queuing the network traffic.

01 Jan 2007
TL;DR: A scalable algorithm for statistically estimating a traffic matrix from the readily available link counts that relies on a divide-andconquer strategy to lower the computational cost without losing estimation accuracy.
Abstract: Traffic matrices are extremely useful for network configuration, management, engineering, and pricing Direct measurement is, however, expensive in general and impossible in some cases This paper proposes a scalable algorithm for statistically estimating a traffic matrix from the readily available link counts It relies on a divide-andconquer strategy to lower the computational cost without losing estimation accuracy The proposed algorithm is tested on a real network with 18 nodes The estimates are comparable to the direct estimates but require dramatically less computation Keywords—divide-and-conquer, MLE, link counts, scalability, statistical estimation, traffic matrix

Proceedings ArticleDOI
01 Dec 2007
TL;DR: A method for creating a model of the full TCP application workload that generates the traffic flowing on a network link and how workload models can be re-sampled to generate statistically valid randomized and rescaled variations is presented.
Abstract: In order to perform valid experiments, traffic generators used in network simulators and testbeds require contemporary models of traffic as it exists on real network links. Ideally one would like a model of the workload created by the full range of applications running on the Internet today. Unfortunately, at best, all that is available to the research community are a small number of models for single applications or application classes such as the web or peer-to-peer. We present a method for creating a model of the full TCP application workload that generates the traffic flowing on a network link. From this model, synthetic workload traffic can be generated in a simulation that is statistically similar to the traffic observed on the real link. The model is generated automatically using only a simple packet-header trace and requires no knowledge of the actual identity or mix of TCP applications on the network. We present the modeling method and a traffic generator that will enable researchers to conduct network experiments with realistic, easy-to-update TCP application workloads. An extensive validation study is performed using Abilene and university traces. The method is validated by comparing traces of synthetically generated traffic to the original traces for a set of important measures of realism. We also show how workload models can be re-sampled to generate statistically valid randomized and rescaled variations.

Proceedings ArticleDOI
Geza Szabo1, Daniel Orincsay1, Balázs Peter Gerö1, Sandor Gyori1, Tamas Borsos1 
22 Oct 2007
TL;DR: In this paper, the authors compare and benchmark the currently known traffic classification methods on network traces captured in an operational 3G mobile network and propose a novel combined method aiming at improving the completeness and accuracy of classification.
Abstract: Detailed knowledge about the traffic mixture is essential for network operators and administrators, as it is a key input for numerous network management activities. Several traffic classification approaches co-exist in the literature, but none of them performs well for all different application traffic types present in the Internet. In this study we compare and benchmark the currently known traffic classification methods on network traces captured in an operational 3G mobile network. Utilizing the experiences about the strengths and weaknesses of the existing approaches, a novel combined method is proposed aiming at improving the completeness and accuracy of classification. The novel method is based on a complex decision mechanism, which can provide appropriate identification for each different application type. As a main contribution, with the help of the new method it is shown that applications previously used only in fixed access networks may appear in mobile broadband environment.

Proceedings ArticleDOI
23 Oct 2007
TL;DR: This study focuses on the statistical analysis of the traffic load measured in a campus-wide IEEE802.11 infrastructure at each AP and found that the time-series of traffic load at a given AP has a small intrinsic dimension.
Abstract: Network traffic load in an IEEE802.11 infrastructure arises from the superposition of traffic accessed by wireless clients associated with access points (APs). An accurate characterization of these data can be beneficial in modelling network traffic and addressing a variety of problems including coverage planning, resource reservation and network monitoring for anomaly detection. This study focuses on the statistical analysis of the traffic load measured in a campus-wide IEEE802.11 infrastructure at each AP.Using the Singular Spectrum Analysis approach, we found that the time-series of traffic load at a given AP has a small intrinsic dimension. In particular, these time-series can be accurately modelled using a small number of leading (principal) components. This proved to be critical for understanding the main features of the components forming the network traffic.The statistical analysis of leading components has demonstrated that even a few first components form the main part of the information. The residual components capture the small irregular variations, which do not fit in the basic part of the network traffic and can be interpreted as a stochastic noise. Based on these properties, we also studied contributions of the various components to the overall structure of the traffic load of an AP and its variation over time.

01 Jan 2007
TL;DR: This research aims at developing an integrated dynamic simulation-assignment model, DynaTAIWAN under mixed traffic flow conditions, for Advanced Traffic Management Systems as well as Advanced Traveler Information Systems.
Abstract: This research aims at developing an integrated dynamic simulation-assignment model, DynaTAIWAN under mixed traffic flow conditions, for Advanced Traffic Management Systems as well as Advanced Traveler Information Systems. The model is composed of two layers, namely simulation-layer and real-time control layer. The simulation layer is designed to simulate traffic flow patterns according to assumed tripmaker characteristics and/or under a set of given conditions; the real-time control layer receives real-time vehicle information and forecast short-term traffic flow patterns. In this paper, the simulation layer is discussed in detail and numerical experiments are conducted to illustrate functional capabilities of the proposed model. In the simulation process, each vehicle is moved and tracked individually. Four different vehicle types are explicitly considered in DynaTAIWAN, including car, bus, motorcycle, and truck. Vehicles are moving along the link through macroscopic flow relationships, speeds of each type of vehicle are adjusted. Numerical experiments are conducted in a 50-node test network and a Taichung City Network.

Proceedings ArticleDOI
06 Nov 2007
TL;DR: This paper proposes a new development paradigm, simulation-based augmented reality, in which simulation is used to enhance development on physical hardware by seamlessly integrating a running simulated network with a physical deployment in a way that is transparent to each.
Abstract: Software development for sensor network is made difficult by resource constrained sensor devices, distributed system complexity, communication unreliability, and high labor cost. Simulation, as a useful tool, provides an affordable way to study algorithmic problems with flexibility and controllability. However, in exchange for speed simulation often trades detail that ultimately limits its utility. In this paper, we propose a new development paradigm, simulation-based augmented reality, in which simulation is used to enhance development on physical hardware by seamlessly integrating a running simulated network with a physical deployment in a way that is transparent to each. The advantages of such an augmented network include the ability to study a large sensor network with limited hardware and the convenience of studying a part of the physical network with simulation's debugging, profiling and tracing capabilities. We implement the augmented reality system based on a sensor network simulator with high fidelity and high scalability. Key to the design are "super" sensor nodes which are half virtual and half physical that interconnect simulation and physical network with fine-grained traffic forwarding and accurate time synchronization. Our results detail the overhead associated with integrating live and simulated networks and the timing accuracy between virtual and physical parts of the network. We also discuss various application scenarios for our system.