WorldWideScience

Sample records for channel traffic requires

  1. Camouflaging Timing Channels in Web Traffic

    OpenAIRE

    Sellke, Sarah H; Wang, Chih-Chun; Bagchi, Saurabh; Shroff, Ness B.

    2009-01-01

    Web traffic accounts for more than half of Internet traffic today. Camouflaging covert timing channels in Web traffic would be advantageous for concealment. In this paper, we investigate the possibility of disguising network covert timing channels as HTTP traffic to avoid detection. Extensive research has shown that Internet traffic, including HTTP traffic, exhibits self-similarity and long range persistence. Existing covert timing channels that mimic i.i.d. legitimate traffic cannot imitate ...

  2. MODELING OF VEHICULAR STEERING EFFICIENCY IN TRAFFIC DIRECTION MOTION CHANNEL

    OpenAIRE

    V. A. Ganai; S. A. O. Diab Abdullah

    2011-01-01

    The paper formulates and solves an actual problem pertaining to vehicular steering efficiency in traffic direction motion channel. Models of operator-drivers with low, medium and high rates in motivational perception of road conditions and also a model for controlling a traffic direction motion have been taken into ccount in the paper.  Modeling has been done by using MATLAB.

  3. MODELING OF VEHICULAR STEERING EFFICIENCY IN TRAFFIC DIRECTION MOTION CHANNEL

    Directory of Open Access Journals (Sweden)

    V. A. Ganai

    2011-01-01

    Full Text Available The paper formulates and solves an actual problem pertaining to vehicular steering efficiency in traffic direction motion channel. Models of operator-drivers with low, medium and high rates in motivational perception of road conditions and also a model for controlling a traffic direction motion have been taken into ccount in the paper.  Modeling has been done by using MATLAB.

  4. Length Requirement of Self-Similar Network Traffic

    Institute of Scientific and Technical Information of China (English)

    RAOYunhua; XUZhongyang; LIUZhenglin

    2004-01-01

    It is important to study the second-order character of self-similar network traffic in performance evaluation. Especially in real-time applications, traffic autocorrelation is a useful analysis tool, so how to estimate it quickly and reliably is a significant problem. In this paper,we studied the estimation and evaluation of self-similar network traffic autocorrelation structure. With the model of Fractional Gaussian noise (FGN) process, we obtained a simple variance expression of estimated autocorrelation,which is the function of Hurst parameter (H) and traffic data length. The relationship among Hurst parameter, accuracy of the estimated autocorrelation and required data length of self-similar traffic shows that the accuracy of estimated autocorrelation decreases with the increasing Hurst parameter and with the decreasing data length too. But over-long sampled data could not improve the accuracy of estimated autocorrelation remarkably. Furthermore, a sharp variety of accuracy is discovered between H > 0.75 and H < 0.75. It is a very interesting phenomenon that had not been reported before. This shows that Hurst parameter could reflect the second-order character of selfsimilarity, but it is not enough to capture all the traffic features. Experiments, which were performed with synthetical FGN traffics, confirmed the validity of our results.It can also be a reference in estimating the autocorrelation function of other self-similar processes.

  5. Pyridoxine requirements of channel catfish.

    Science.gov (United States)

    Andrews, J W; Murai, T

    1979-04-01

    In 20 and 12 week feeding trials, channel catfish fingerlings were fed purified diets containing five levels (0, 5, 10, 20, and 30 mg/kg) and six levels (0, 1, 2, 5, 10, and 20 mg/kg) of supplemental pyridoxine hydrochloride. Fish fed unsupplemented diets (pyridoxine content of 1.2 mg/kg) were characterized by anoxeria, nervous disorders, tetany, greenish-blue body coloration, and eventual mortality. Anemia, which has been reported in pyridoxine deficient salmonids, was not observed in pyridoxine deficient catfish. However, a microcytic, normochromic anemia was observed in groups fed high dietary levels of pyridoxine (20 mg/kg or greater). The dietary pyridoxine level required for maximal growth was approximately 3 mg/kg of diet. All other deficiency signs were prevented by 2.2 mg/kg of diet. PMID:430257

  6. 78 FR 51664 - Vessel Traffic Service Updates, Including Establishment of Vessel Traffic Service Requirements...

    Science.gov (United States)

    2013-08-21

    ... for Port Arthur, Texas and Expansion of VTS Special Operating Area in Puget Sound'' (77 FR 55439). The... pool gauge is at approximately 13.0 feet or above. Lower Mississippi River--0036699952: New Orleans... of Vessel Traffic Service Requirements for Port Arthur, Texas and Expansion of VTS Special...

  7. A Model for the Handover Traffic and Channel Occupancy Time in LEO Satellite Networks

    Institute of Scientific and Technical Information of China (English)

    WangJingyu; YaoYongyang

    1995-01-01

    This paper presents a method to determine the parameters of the traffic model for the LEO satellite networks-the handover traffic and the mean channel occupancy time.The main idea is that the handover traffic is mainly due to the movement of the satellites and the velocity of the mobile terminals and earth rotation is ignored.The performance level can be calculated accord-ing to different handover queuing model.

  8. A virtual channel network-on-chip for GT and BE traffic

    OpenAIRE

    Kavaldjiev, Nikolay; Smit, Gerard J.M.; Jansen, Pierre G.; Wolkotte, Pascal T.

    2005-01-01

    This paper presents an on-chip network for a run-time reconfigurable System-on-Chip. The network uses packet-switching with virtual channels. It can provide guaranteed services as well as best effort services. The guaranteed services are based on virtual channel allocation, in contrast to other on-chip networks where guarantees are provided by time-division multiplexing. The network is particularly suitable for systems in which the traffic is dominated by streams. We model the data traffic in...

  9. Analysis of Traffic Parameter Estimation and Its Impacts on Wireless Channel

    Institute of Scientific and Technical Information of China (English)

    徐玉滨; 沙学军; 强蔚

    2004-01-01

    Wide band or broadband access was paid much attention with the development of radio transmission technique. The wireless access control procedure play an important role in this type of system and efficiency of control algorithm has a great impact on throughput of channel resource. Based on wide band network control model and the characteristics of radio channel, this paper proposed a channel traffic estimation method and then performed a dynamic parameter control procedure and give detail analysis on estimation error and its impact on channel throughput and delay performance. Computation and simulation of system performance show a positive solution on system design.

  10. Wind farms' influences for traffic safety. Study of distance requirements for road traffic, railway traffic, sea traffic and air travel; Tuulivoimaloiden vaikutukset liikenneturvallisuuteen. Selvitys etaeisyysvaatimuksista tie-, rautatie-, meri- ja lentoliikenteen osalta

    Energy Technology Data Exchange (ETDEWEB)

    Hytoenen, K.; Harju, M.; Piispanen, J.; Haulos, S.

    2012-11-15

    As wind power projects, both design and implementation, have increased rapidly, wind power manufacturers have stated that infrastructure of traffic restricts and complicates implementation of wind power projects. Failure of wind farm and both snow and ice thrown from blades and tower are commonly thought to be dangerous for settlement and for road, railway and sea traffic. Based on the accessible information accidents, which are connected to wind farms, won't cause notable harm for outsiders. Majority of the human injury and fatal accidents concerns the personnel of the wind farm in implementation and operational phases, not outsiders. Purpose of this study has been to clarify how distances requirements in different forms of traffic in Finland differ from other countries that are included in this comparison, and to find grounds for possibly revising these guidelines. In Finland there are still longest distance requirements when placing wind farm nearby the main roads, even after Finnish Traffic Agency revised guidelines in 2012. Regarding roads, differences between all the countries were minor. Also distance requirements regarding railways differ relatively little. Sweden has shortest distance requirement. Distance requirements in Finland and Denmark have been reduced in past few years. Any of these countries have not stated actual defined distance requirements related for example to shipping channels or lanes. International Civil Aviation Organization ICAO has settled internationally rules for obstacle limitation surface nearby airports and marking flight obstacles. Countries have stated national aviation regulations according to these rules and for this reason these regulations are quite consistent. In this study distance requirements are recommended to be calculated for certain basis. In case of roads and railways a general minimum distance requirement is suggested to be 1 x wind farm overall height. Road owner is allowed to require higher distance for

  11. The Performance Analysis of Traffic Channel Coding in Digital Trunking System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The encoding and decoding processes of traffic channel in digital trunking system are studied. On the basis of computer simulation, the BER (bit error ratio) with different RCPC decoding step is analyzed. As a result, the optimal RCPC decoding step is provided, which gives essential theoretical evidences for the implementation of digital trunking system.

  12. Performance Analysis of Spectrum Handoff for Cognitive Radio Ad Hoc Networks without Common Control Channel under Homogeneous Primary Traffic

    CERN Document Server

    Song, Yi

    2011-01-01

    Cognitive radio (CR) technology is regarded as a promising solution to the spectrum scarcity problem. Due to the spectrum varying nature of CR networks, unlicensed users are required to perform spectrum handoffs when licensed users reuse the spectrum. In this paper, we study the performance of the spectrum handoff process in a CR ad hoc network under homogeneous primary traffic. We propose a novel three dimensional discrete-time Markov chain to characterize the process of spectrum handoffs and analyze the performance of unlicensed users. Since in real CR networks, a dedicated common control channel is not practical, in our model, we implement a network coordination scheme where no dedicated common control channel is needed. Moreover, in wireless communications, collisions among simultaneous transmissions cannot be immediately detected and the whole collided packets need to be retransmitted, which greatly affects the network performance. With this observation, we also consider the retransmissions of the collid...

  13. What is required to guarantee data quality for regional traffic management. Implementation of traffic data quality management in the Middle Netherlands

    NARCIS (Netherlands)

    Seelen, P.A.G.; Vrancken, J.L.M.

    2013-01-01

    VERDER, a partnership of different governmental organizations in the Middle Netherlands, initiated different projects for regional traffic management to better use existing road capacity and safeguard mobility in the Middle Netherlands. This active form of traffic management requires traffic data wi

  14. 77 FR 64076 - Vessel Traffic Service Updates, Including Establishment of Vessel Traffic Service Requirements...

    Science.gov (United States)

    2012-10-18

    ... 10, 2012 (77 FR 55439), which proposes to revise and update the Vessel Traffic Service regulations in..., 2012 (77 FR 55439) for instructions on submitting comments. FOR FURTHER INFORMATION CONTACT: Lieutenant... On September 10, 2012, the Coast Guard published a notice of proposed rulemaking (NPRM) (77 FR...

  15. Data requirements for traffic control on a macroscopic level

    NARCIS (Netherlands)

    Knoop, V.L.; Van Lint, J.W.C.; Hoogendoorn, S.P.

    2011-01-01

    With current techniques, traffic monitoring and control is a data intensive process. Network control on a higher level, using high level variables, can make this process less data demanding. The macroscopic fundamental diagram relates accumulation, i.e. the number of vehicles in an area, to the netw

  16. TRP channels and traffic-related environmental pollution-induced pulmonary disease.

    Science.gov (United States)

    Akopian, Armen N; Fanick, E Robert; Brooks, Edward G

    2016-05-01

    Environmental pollutant exposures are major risk factors for adverse health outcomes, with increased morbidity and mortality in humans. Diesel exhaust (DE) is one of the major harmful components of traffic-related air pollution. Exposure to DE affects several physiological systems, including the airways, and pulmonary diseases are increased in highly populated urban areas. Hence, there are urgent needs to (1) create newer and lesser polluting fuels, (2) improve exhaust aftertreatments and reduce emissions, and (3) understand mechanisms of actions for toxic effects of both conventional and cleaner diesel fuels on the lungs. These steps could aid the development of diagnostics and interventions to prevent the negative impact of traffic-related air pollution on the pulmonary system. Exhaust from conventional, and to a lesser extent, clean fuels, contains particulate matter (PM) and more than 400 additional chemical constituents. The major toxic constituents are nitrogen oxides (NOx) and polycyclic aromatic hydrocarbons (PAHs). PM and PAHs could potentially act via transient receptor potential (TRP) channels. In this review, we will first discuss the associations between DE from conventional as well as clean fuel technologies and acute and chronic airway inflammation. We will then review possible activation and/or potentiation of TRP vanilloid type 1 (TRPV1) and ankyrin 1 (TRPA1) channels by PM and PAHs. Finally, we will discuss and summarize recent findings on the mechanisms whereby TRPs could control the link between DE and airway inflammation, which is a primary determinant leading to pulmonary disease.

  17. TRAFFIC CHANNEL SIR ESTIMATION BASED ON REVERSE PILOT CHANNEL IN cdma2000

    Institute of Scientific and Technical Information of China (English)

    Zhou Hua Yang Dacheng

    2004-01-01

    Signal-to-Interference Ratio(SIR) is a very important metric of communication link quality. For wireless cellular systems, several control mechanisms, such as power control mechanisms, rate control mechanisms, and allocation of radio resource, are based on SIR estimation.In previous researches, most of researchers concentrated on WCDMA systems, in which pilot symbol is time-multiplexed with data symbol; the method developed in this case is not feasible for cdma2000 systems where pilot symbol is code-multiplexed with data symbol. This paper first develops the SIR estimators based on the reverse pilot channel and then derives the approximate analytic expression for its Mean Squared Error (MSE) function, the accuracy of which is validated through simulation. It is shown that the MSE of the new SIR estimator is significantly smaller than that of other widely used SIR estimators, especially in low SIR case. Finally, the estimate quality of the proposed method is further improved by long-termly averaging the sample interference.

  18. Protection Over Asymmetric Channels, S-MATE: Secure Multipath Adaptive Traffic Engineering

    OpenAIRE

    Aly, Salah A.; Ansari, Nirwan; Poor, H. Vincent; Walid, Anwar I.

    2010-01-01

    Several approaches have been proposed to the problem of provisioning traffic engineering between core network nodes in Internet Service Provider (ISP) networks. Such approaches aim to minimize network delay, increase capacity, and enhance security services between two core (relay) network nodes, an ingress node and an egress node. MATE (Multipath Adaptive Traffic Engineering) has been proposed for multipath adaptive traffic engineering between an ingress node (source) and an egress node (dest...

  19. Laboratory evaluation of dynamic traffic assignment systems: Requirements, framework, and system design

    Energy Technology Data Exchange (ETDEWEB)

    Miaou, S.-P.; Pillai, R.S.; Summers, M.S.; Rathi, A.K. [Oak Ridge National Lab., TN (United States); Lieu, H.C. [Federal Highway Administration, McLean, VA (United States). Intelligent Systems Div.

    1997-01-01

    The success of Advanced Traveler Information 5ystems (ATIS) and Advanced Traffic Management Systems (ATMS) depends on the availability and dissemination of timely and accurate estimates of current and emerging traffic network conditions. Real-time Dynamic Traffic Assignment (DTA) systems are being developed to provide the required timely information. The DTA systems will provide faithful and coherent real-time, pre-trip, and en-route guidance/information which includes routing, mode, and departure time suggestions for use by travelers, ATIS, and ATMS. To ensure the credibility and deployment potential of such DTA systems, an evaluation system supporting all phases of DTA system development has been designed and presented in this paper. This evaluation system is called the DTA System Laboratory (DSL). A major component of the DSL is a ground- truth simulator, the DTA Evaluation System (DES). The DES is envisioned to be a virtual representation of a transportation system in which ATMS and ATIS technologies are deployed. It simulates the driving and decision-making behavior of travelers in response to ATIS and ATMS guidance, information, and control. This paper presents the major evaluation requirements for a DTA Systems, a modular modeling framework for the DES, and a distributed DES design. The modeling framework for the DES is modular, meets the requirements, can be assembled using both legacy and independently developed modules, and can be implemented as a either a single process or a distributed system. The distributed design is extendible, provides for the optimization of distributed performance, and object-oriented design within each distributed component. A status report on the development of the DES and other research applications is also provided.

  20. BER and FER Prediction of Control and Traffic Channels for a GSM type of interface

    DEFF Research Database (Denmark)

    Wigard, Jeroen; Nielsen, Thomas Toftegaard; Michaelsen, Per Henrik;

    1998-01-01

    Performance analysis of a mobile communications system is often done separately at network and at link level. It is difficult to study a modern mobile communications system like GSM analytically, due to the complexity. Hence simulations are used. It is desirable to include all link aspects...... in a network simulator. The accuracy is within 0.2 dB in case of the BER and 0.5 for the FER. Both traffic and control channels are studied and the method is independent of hopping sequences and speed...... in a network simulator, but without having to simulate every single link, since this would be to time consuming. In this paper a method is presented to find the BER and FER from the signal to interference (C/I) values for a GSM type of air-interface, which can be used for integration of link aspects...

  1. Kir6.2△C26 Channel Traffics to Plasma Membrane by Constitutive Exocytosis

    Institute of Scientific and Technical Information of China (English)

    Ping ZHAO; Wei LI; Yong-Ming DONG; Dan ZHU; An-Lian QU; Tao XU; Zheng-Xing WU

    2006-01-01

    Adenosine triphosphate (ATP)-sensitive K+ (KATP) channels regulate many cellular functions by coupling the metabolic state of the cell to the changes in membrane potential. Truncation of C-terminal 26 amino acid residues of Kir6.2 protein (Kir6.2△C26) deletes its endoplasmic reticulum retention signal, allowing functional expression of Kir6.2 in the absence of sulfonylurea receptor subunit. pEGFP-Kir6.2△C26 and pKir6.2△C26-IRES2-EGFP expression plasmids were constructed and transfected into HEK293 cells. We identified that Kir6.2△C26 was localized on the plasma membrane and trafficked to the plasmalemma by means of constitutive exocytosis of Kir6.2△C26 transport vesicles, using epi-fluorescence and total internal reflection fluorescence microscopy. Our electrophysiological data showed that Kir6.2△C26 alone expressed KATP currents, whereas EGFP-Kir6.2△C26 fusion protein displayed no KATP channel activity.

  2. Pannexin2 oligomers localize into endosomal vesicles in mammalian cells while Pannexin1 channels traffic to the plasma membrane

    Directory of Open Access Journals (Sweden)

    Daniela eBoassa

    2015-02-01

    Full Text Available Pannexin2 (Panx2 is the largest of three members of the pannexin proteins. Pannexins are topologically related to connexins and innexins, but serve different functional roles than forming gap junctions. We previously showed that pannexins form oligomeric channels but unlike connexins and innexins, they form only single membrane channels. High levels of Panx2 mRNA and protein in the Central Nervous System (CNS have been documented. Whereas Pannexin1 (Panx1 is fairly ubiquitous and Pannexin3 (Panx3 is found in skin and connective tissue, both are fully glycosylated, traffic to the plasma membrane and have functions correlated with extracellular ATP release. Here, we describe trafficking and subcellular localizations of exogenous Panx2 and Panx1 protein expression in MDCK, HeLa and HEK293T cells as well as endogenous Panx1 and Panx2 patterns in the CNS. Panx2 was found in intracellular localizations, was partially N-glycosylated, and localizations were non-overlapping with Panx1. Confocal images of hippocampal sections immunolabeled for the astrocytic protein GFAP, Panx1 and Panx2 demonstrated that the two isoforms, Panx1 and Panx2, localized at different subcellular compartments in both astrocytes and neurons. Using recombinant fusions of Panx2 with appended genetic tags developed for correlated light and electron microscopy and then expressed in different cell lines, we determined that Panx2 is localized in the membrane of intracellular vesicles and not in the endoplasmic reticulum as initially indicated by calnexin colocalization experiments. Dual immunofluorescence imaging with protein markers for specific vesicle compartments showed that Panx2 vesicles are early endosomal in origin. In electron tomographic volumes, cross-sections of these vesicles displayed fine structural details and close proximity to actin filaments. Thus, pannexins expressed at different subcellular compartments likely exert distinct functional roles, particularly in the

  3. TRANSIMS traffic flow characteristics

    OpenAIRE

    Nagel, Kai; Stretz, Paula; Pieck, Martin; Donnelly, Rick; Barrett, Christopher L.

    1997-01-01

    Knowledge of fundamental traffic flow characteristics of traffic simulation models is an essential requirement when using these models for the planning, design, and operation of transportation systems. In this paper we discuss the following: a description of how features relevant to traffic flow are currently under implementation in the TRANSIMS microsimulation, a proposition for standardized traffic flow tests for traffic simulation models, and the results of these tests for two different ve...

  4. Requirements for traffic assignment models for strategic transport planning: a critical assessment

    NARCIS (Netherlands)

    Bliemer, M.; Raadsen, M.; De Romph, E.; Smits, E.

    2013-01-01

    Transport planning models are used all over the world to assist in the decision making regarding investments in infrastructure and transport services. Traffic assignment is one of the key components of transport models, which relate travel demand to infrastructure supply, by simulating (future) rout

  5. TRAFFIC OFFLOADING IMPACT ON THE PERFORMANCE OF CHANNEL-AWARE/QOS-AWARE SCHEDULING ALGORITHMS FOR VIDEO-APPLICATIONS OVER LTE-A HETNETS USING CARRIER AGGREGATION

    Directory of Open Access Journals (Sweden)

    Najem N. Sirhan

    2015-09-01

    Full Text Available Long Term Evolution (LTE is defined by the Third Generation Partnership Project (3GPP standards as Release 8/9. The LTE supports at max 20 MHz channel bandwidth for a carrier. The number of LTE users and their applications are increasing, which increases the demand on the system BW. A new feature of the LTE-Advanced (LTE-A which is defined in the 3GPP standards as Release 10/11 is called Carrier Aggregation (CA, this feature allows the network to aggregate more carriers in-order to provide a higher bandwidth. Carrier Aggregation has three main cases: Intra-band contiguous, Intra-band non-contiguous, Inter-band contiguous. In addition to the Carrier Aggregation feature, LTE-A supports Heterogeneous Networks (HetNets. HetNets consists of a mix of macro-cells, remote radio heads, and low power nodes such as pico-cells, and femto-cells. HetNets allow cellular network operators to support higher data traffic by offloading it to a smaller cells such as femto-cells. The aim of this paper is to evaluate the Quality of Service (QoS performance of the Modified Largest Weighted Delay First (MLWDF, the Exponential Rule (Exp-Rule, and the Logarithmic Rule (Log-Rule scheduling algorithms while offloading 50% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to ten femto-cells, and to compare it with the case in-which traffic offloading is not applied. The QoS performance evaluation is based on the system's average throughput, Packet Loss Rate(PLR, average packet delay, and fairness among users. The LTE-Sim-5 with modifications is used in the simulation process. Simulation results show that offloading 100% of the Macro-cell's traffic to five femtocells had the highest maximum throughput, and the best PLR values especially when using the Log-Rule, in-which using it maintained the PLR values around 0.15 despite increasing the number of users. The least average packet delay was

  6. Study and Simulation of Traffic Behavior in Cellular Network

    Science.gov (United States)

    Madhup, D. K.; Shrestha, C. L.; Sharma, R. K.

    2007-07-01

    Cellular radio systems accommodate a large number of users with a limited radio spectrum. The concept of trunking allows a large number of users to share the relatively small number of channels in a cell by providing access to each user, on demand, from a pool of available channels. Traffic engineering deals with provisioning of communication circuits in a given area for a number of subscribers with a required grade of service. Traffic in any cell depends upon the number of users, the average request rate and average call duration. Certain number of channels is required for the required GOS. To design an optimum capacity cellular system, traffic behavior on that system is important. The number of channel required can be estimated by using Erlang formula and Erlang table. Erlang table is not always useful to calculate the probability of blocking in various complex scenarios such as channel borrowing strategies. When the total number of channel available in a given cell are divided to serve partly for newly generated calls and partly for handover calls, and if they use dynamic channel assignment strategies like channel borrowing, then the probability of blocking can't be calculated from Erlang table. Simulation model of the behavior help us to determine the blocking and the channel utilization while using various channel assignment strategies. The title "Study and Simulation of Traffic Behavior in Cellular Network" entail the study of the blocking probability of traffic in cellular network for static channel assignment strategies and dynamic channel borrowing strategies through MATLAB programming language and graphic user interface (GUI). The result shows that the dynamic scheme can perform better than static maximizing the overall utilization of the circuits and minimizing the overall blocking.

  7. Traffic Engineering of Cellular Wireless Communication Systems

    DEFF Research Database (Denmark)

    Iversen, Villy Bæk

    2002-01-01

    In mobile communications an efficient utilisation of the channels is of great importance. In this paper we describe the basic principles for obtaining the maximum utilisation and study strategies for obtaining these limits. In general a high degree of sharing is efficient, but requires service pr...... arrival processes, and multi-rate (multi-media) traffic for third generation systems....

  8. The cyclic nucleotide gated cation channel AtCNGC10 traffics from the ER via Golgi vesicles to the plasma membrane of Arabidopsis root and leaf cells

    Directory of Open Access Journals (Sweden)

    Andres Marilou A

    2007-09-01

    Full Text Available Abstract Background The cyclic nucleotide-gated ion channels (CNGCs maintain cation homeostasis essential for a wide range of physiological processes in plant cells. However, the precise subcellular locations and trafficking of these membrane proteins are poorly understood. This is further complicated by a general deficiency of information about targeting pathways of membrane proteins in plants. To investigate CNGC trafficking and localization, we have measured Atcngc5 and Atcngc10 expression in roots and leaves, analyzed AtCNGC10-GFP fusions transiently expressed in protoplasts, and conducted immunofluorescence labeling of protoplasts and immunoelectron microscopic analysis of high pressure frozen leaves and roots. Results AtCNGC10 mRNA and protein levels were 2.5-fold higher in roots than leaves, while AtCNGC5 mRNA and protein levels were nearly equal in these tissues. The AtCNGC10-EGFP fusion was targeted to the plasma membrane in leaf protoplasts, and lightly labeled several intracellular structures. Immunofluorescence microscopy with affinity purified CNGC-specific antisera indicated that AtCNGC5 and AtCNGC10 are present in the plasma membrane of protoplasts. Immunoelectron microscopy demonstrated that AtCNGC10 was associated with the plasma membrane of mesophyll, palisade parenchyma and epidermal cells of leaves, and the meristem, columella and cap cells of roots. AtCNCG10 was also observed in the endoplasmic reticulum and Golgi cisternae and vesicles of 50–150 nm in size. Patch clamp assays of an AtCNGC10-GFP fusion expressed in HEK293 cells measured significant cation currents. Conclusion AtCNGC5 and AtCNGC10 are plasma membrane proteins. We postulate that AtCNGC10 traffics from the endoplasmic reticulum via the Golgi apparatus and associated vesicles to the plasma membrane. The presence of the cation channel, AtCNGC10, in root cap meristem cells, cell plate, and gravity-sensing columella cells, combined with the previously reported

  9. IDENTIFYING NETWORK LOAD BALANCING REQUIREMENTS ON HISTORICAL TRAFFIC FLOW USING MACHINE LEARNING APPROACH FOR FLEXIBLE MULTIPATH NETWORKS

    Directory of Open Access Journals (Sweden)

    K BALAMURUGAN

    2010-08-01

    Full Text Available Multipath routing uses several paths to distribute traffic from a source to destination. This not only improves network performance but also achieves load balancing and fault tolerance. Though multipath routing is not deployed widely in the internet, current systems chooses the paths with the same lowest cost to the destination and the same administrative distance.In this paper we propose a flexible multipath network wherein multipath routing algorithm is invoked when the quality of service is affected. Our proposal provides a method to gradually shift from a single path existing network to a reliable multipath network in the future.We have used machine learning approach to identify the instance when network load balancing is required with good results.

  10. Traffic Accident Prediction Model Implementation in Traffic Safety Management

    OpenAIRE

    Wen, Keyao

    2009-01-01

    As one of the highest fatalities causes, traffic accidents and collisions always requires a large amounteffort to be reduced or prevented from occur. Traffic safety management routines therefore always needefficient and effective implementation due to the variations of traffic, especially from trafficengineering point of view apart from driver education.Traffic Accident Prediction Model, considered as one of the handy tool of traffic safety management,has become of well followed with interest...

  11. Reducing prospective memory error and costs in simulated air traffic control: External aids, extending practice, and removing perceived memory requirements.

    Science.gov (United States)

    Loft, Shayne; Chapman, Melissa; Smith, Rebekah E

    2016-09-01

    In air traffic control (ATC), forgetting to perform deferred actions-prospective memory (PM) errors-can have severe consequences. PM demands can also interfere with ongoing tasks (costs). We examined the extent to which PM errors and costs were reduced in simulated ATC by providing extended practice, or by providing external aids combined with extended practice, or by providing external aids combined with instructions that removed perceived memory requirements. Participants accepted/handed-off aircraft and detected conflicts. For the PM task, participants were required to substitute alternative actions for routine actions when accepting aircraft. In Experiment 1, when no aids were provided, PM errors and costs were not reduced by practice. When aids were provided, costs observed early in practice were eliminated with practice, but residual PM errors remained. Experiment 2 provided more limited practice with aids, but instructions that did not frame the PM task as a "memory" task led to high PM accuracy without costs. Attention-allocation policies that participants set based on expected PM demands were modified as individuals were increasingly exposed to reliable aids, or were given instructions that removed perceived memory requirements. These findings have implications for the design of aids for individuals who monitor multi-item dynamic displays. (PsycINFO Database Record PMID:27608067

  12. How Much Feedback Is Required for TDD Multi-Antenna Broadcast Channels with User Selection?

    Directory of Open Access Journals (Sweden)

    Salim Umer

    2010-01-01

    Full Text Available The enormous gains in a multi-antenna transmitter broadcast channel require the Channel State Information at the Transmitter (CSIT. Although the fundamental question "How much feedback is required for a broadcast channel?" has been treated in the literature to some extent, a more comprehensive treatment is certainly desirable. We study the time-division duplex broadcast channel with initial assumption of channel state information (CSI neither at the base station (BS nor at the users' side. We provide two transmission strategies through which the BS and the users get necessary CSI. We derive novel lower and upper bounds for the sum rate reflecting the rate loss compared to a perfect CSIT system. Corresponding approximate sum rate expressions are also developed for both schemes. These expressions fully capture the benefits of the CSIT feedback, allowing multi-user diversity gain and better inter-user interference cancellation, and the cost of exchange of information required. These expressions can be optimized for any set of system parameters to unveil the trade-off between the cost and the gains associated to feedback. Thus they allow to characterize the optimal amount of feedback which maximizes the sum rate of the broadcast channel, a well-accepted metric of system performance at the physical layer.

  13. Feeders-TDMA: a distributed-control algorithm for satellite channel capacity assignment in a mixed traffic and faded environment

    OpenAIRE

    Celandroni, Nedo; Ferro, Erina; Potort?, Francesco

    1997-01-01

    This paper presents Faded Environments Effective Distributed Engineering Redundant Signalling (FEEDERS), an access scheme for sharing, in time division multiple access (TDMA) mode, the capacity of a satellite channel among a number of stations, on the basis of user demand, This scheme and its companion Distributed Allocation with Request In Fixed Slots (DRIFS), result from a study carried out by the authors on distributed-control protocols for geostationary satellite access. Both protocols de...

  14. Oligosaccharide composition of the neurotoxin responsive Na+ channel and the requirement of sialic acid for activity

    International Nuclear Information System (INIS)

    The neurotoxin responsive Na+ channel was purified to homogeneity in an 18% yield from a clonal cell line of mouse neuroblastoma, N-18, metabolically labeled with L-[3H]fucose. The Na+ channel, a glycoprotein, M/sub r/=200,000 (gradient 7-14% PAGE) was digested with Pronase and the glycopeptides were characterized by serial lectin affinity chromatography. greater than 90% of the oligosaccharides contained sialic acid and 18% were biantennary, 39% were triantennary and 30% tetraantennary. The glycoprotein was reconstituted into artificial phospholipid vesicles and 86Rb flux was stimulated (65%) by 200 μM veratridine and 1.2 μg of scorpion venom and was inhibited (95%) by 5 μM tetrodotoxin. The requirement of sialic acid for Na+ channel activity was demonstrated since neuraminidase (0.01 U) treatment of the reconstituted glycoprotein eliminated the response of 86Rb flux to the stimulating neurotoxins. In other experiments, treatment of N-18 cells with 10 μM swainsonine, an inhibitor of glycoprotein processing, altered the oligosaccharide composition of the Na+ channel. When the abnormally glycosylated Na+ channel was reconstituted into artificial phospholipid vesicles, 86Rb flux in response to neurotoxins was impaired. Thus, glycosylation of the polypeptide with oligosaccharides of specific composition and structure is essential for expression of the biological activity of the neurotoxin responsive Na+ channel

  15. Pannexin2 oligomers localize in the membranes of endosomal vesicles in mammalian cells while Pannexin1 channels traffic to the plasma membrane.

    Science.gov (United States)

    Boassa, Daniela; Nguyen, Phuong; Hu, Junru; Ellisman, Mark H; Sosinsky, Gina E

    2014-01-01

    Pannexin2 (Panx2) is the largest of three members of the pannexin proteins. Pannexins are topologically related to connexins and innexins, but serve different functional roles than forming gap junctions. We previously showed that pannexins form oligomeric channels but unlike connexins and innexins, they form only single membrane channels. High levels of Panx2 mRNA and protein in the Central Nervous System (CNS) have been documented. Whereas Pannexin1 (Panx1) is fairly ubiquitous and Pannexin3 (Panx3) is found in skin and connective tissue, both are fully glycosylated, traffic to the plasma membrane and have functions correlated with extracellular ATP release. Here, we describe trafficking and subcellular localizations of exogenous Panx2 and Panx1 protein expression in MDCK, HeLa, and HEK 293T cells as well as endogenous Panx1 and Panx2 patterns in the CNS. Panx2 was found in intracellular localizations, was partially N-glycosylated, and localizations were non-overlapping with Panx1. Confocal images of hippocampal sections immunolabeled for the astrocytic protein GFAP, Panx1 and Panx2 demonstrated that the two isoforms, Panx1 and Panx2, localized at different subcellular compartments in both astrocytes and neurons. Using recombinant fusions of Panx2 with appended genetic tags developed for correlated light and electron microscopy and then expressed in different cell lines, we determined that Panx2 is localized in the membrane of intracellular vesicles and not in the endoplasmic reticulum as initially indicated by calnexin colocalization experiments. Dual immunofluorescence imaging with protein markers for specific vesicle compartments showed that Panx2 vesicles are early endosomal in origin. In electron tomographic volumes, cross-sections of these vesicles displayed fine structural details and close proximity to actin filaments. Thus, pannexins expressed at different subcellular compartments likely exert distinct functional roles, particularly in the nervous system.

  16. HCN channels are not required for mechanotransduction in sensory hair cells of the mouse inner ear.

    Directory of Open Access Journals (Sweden)

    Geoffrey C Horwitz

    Full Text Available The molecular composition of the hair cell transduction channel has not been identified. Here we explore the novel hypothesis that hair cell transduction channels include HCN subunits. The HCN family of ion channels includes four members, HCN1-4. They were originally identified as the molecular correlates of the hyperpolarization-activated, cyclic nucleotide gated ion channels that carry currents known as If, IQ or Ih. However, based on recent evidence it has been suggested that HCN subunits may also be components of the elusive hair cell transduction channel. To investigate this hypothesis we examined expression of mRNA that encodes HCN1-4 in sensory epithelia of the mouse inner ear, immunolocalization of HCN subunits 1, 2 and 4, uptake of the transduction channel permeable dye, FM1-43 and electrophysiological measurement of mechanotransduction current. Dye uptake and transduction current were assayed in cochlear and vestibular hair cells of wildtype mice exposed to HCN channel blockers or a dominant-negative form of HCN2 that contained a pore mutation and in mutant mice that lacked HCN1, HCN2 or both. We found robust expression of HCNs 1, 2 and 4 but little evidence that localized HCN subunits in hair bundles, the site of mechanotransduction. Although high concentrations of the HCN antagonist, ZD7288, blocked 50-70% of the transduction current, we found no reduction of transduction current in either cochlear or vestibular hair cells of HCN1- or HCN2- deficient mice relative to wild-type mice. Furthermore, mice that lacked both HCN1 and HCN2 also had normal transduction currents. Lastly, we found that mice exposed to the dominant-negative mutant form of HCN2 had normal transduction currents as well. Taken together, the evidence suggests that HCN subunits are not required for mechanotransduction in hair cells of the mouse inner ear.

  17. Timing and control requirements for a 32-channel AMU-ADC ASIC for the PHENIX detector

    Energy Technology Data Exchange (ETDEWEB)

    Emery, M.S.; Ericson, M.N.; Britton, C.L. Jr. [and others

    1998-02-01

    A custom CMOS Application Specific Integrated Circuit (ASIC) has been developed consisting of an analog memory unit (AMU) has been developed consisting of an analog memory unit (AMU) and analog to digital converter (ADC), both of which have been designed for applications in the PHENIX experiment. This IC consists of 32 pipes of analog memory with 64 cells per pipe. Each pipe also has its own ADC channel. Timing and control signal requirements for optimum performance are discussed in this paper.

  18. Traffic Light Options

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte

    2007-01-01

    light solvency stress test system introduced by the Danish Financial Supervisory Authority (DFSA) in June 2001. This monitoring system requires L&P companies to submit regular reports documenting the sensitivity of the companies' base capital to certain pre-defined market shocks - the red and yellow......This paper introduces, prices, and analyzes traffic light options. The traffic light option is an innovative structured OTC derivative developed independently by several London-based investment banks to suit the needs of Danish life and pension (L&P) companies, which must comply with the traffic...... light scenarios. These stress scenarios entail drops in interest rates as well as in stock prices, and traffic light options are thus designed to pay off and preserve sufficient capital when interest rates and stock prices fall simultaneously. Sweden's FSA implemented a traffic light system in January...

  19. Traffic Light Options

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte

    light solvency stress test system introduced by the Danish Financial Supervisory Authority (DFSA) in June 2001. This monitoring system requires L&P companies to submit regular reports documenting the sensitivity of the companies' base capital to certain pre-defined market shocks - the red and yellow......This paper introduces, prices, and analyzes traffic light options. The traffic light option is an innovative structured OTC derivative developed independently by several London-based investment banks to suit the needs of Danish life and pension (L&P) companies, which must comply with the traffic...... light scenarios. These stress scenarios entail drops in interest rates as well as in stock prices, and traffic light options are thus designed to pay off and preserve sufficient capital when interest rates and stock prices fall simultaneously. Sweden's FSA implemented a traffic light system in January...

  20. EFFICIENT UTILIZATION OF CHANNELS USING DYNAMIC GUARD CHANNEL ALLOCATION WITH CHANNEL BORROWING STRATEGY IN HANDOFFS

    Directory of Open Access Journals (Sweden)

    Alagu S

    2012-05-01

    Full Text Available User mobility in wireless data networks is increasing because of technological advances and the desire for voice and multimedia applications. These applications, however, require fast handoffs between base stations to maintain the quality of the connections. In this paper, the authors describe the use of novel and efficient data structure which dynamically allocates guard channel for handoffs and introduces the concept of channel borrowing strategy. The proposed scheme allocates the guard channels for handoff requests dynamically, based on the traffic load for certain time period. A new originating call in the cell coverage area also uses these guard channels if they are unused. Our basic idea is to allow Guard channels to be shared between new calls and handoff calls. This approach maximizes the channel utilization. The simulation results prove that the channel borrowing scheme improves the overall throughput.

  1. Traffic Light Detection

    DEFF Research Database (Denmark)

    Philipsen, Mark Philip; Jensen, Morten Bornø; Møgelmose, Andreas;

    2015-01-01

    Traffic light recognition (TLR) is an integral part of any intelligent vehicle, which must function in the existing infrastructure. Pedestrian and sign detection have recently seen great improvements due to the introduction of learning based detectors using integral channel features. A similar push...... database is collected based on footage from US roads. The database consists of both test and training data, totaling 46,418 frames and 112,971 annotated traffic lights, captured in continuous sequences under a varying light and weather conditions. The learning based detector achieves an AUC of 0.4 and 0...

  2. Biochemical requirements for inhibition of Connexin26-containing channels by natural and synthetic taurine analogs.

    Science.gov (United States)

    Tao, Liang; Harris, Andrew L

    2004-09-10

    Previous work has shown that protonated taurine and aminosulfonate pH buffers, including HEPES, can directly and reversibly inhibit connexin channels that contain connexin26 (Cx26) (Bevans, C. G., and Harris, A. L. (1999) J. Biol. Chem. 274, 3711-3719). The structural requirements for this inhibition were explored by studies of the effects of structural analogs of taurine on the activity of Cx26-containing reconstituted hemichannels from native tissue. Several analogs inhibited the channels, with a range of relative affinities and efficacies. Each active compound contains a protonated amine separated from an ionized sulfonate or sulfinate moiety by several methylene groups. The inhibition is eliminated if the sulfonate/sulfinate moiety or the amine is not present. Compounds that contain a protonated amine but lack a sulfonate/sulfinate moiety do not inhibit but do competitively block the effect of the active compounds. Compounds that lack the protonated amine do not significantly inhibit or antagonize inhibition. The results suggest involvement of the protonated amine in binding and of the ionized sulfur-containing moiety in effecting the inhibition. The maximal effect of the inhibitory compounds is enhanced when a carboxyl group is linked to the alpha-carbon. Inhibition but not binding is stereospecific, with l-isomers being inhibitory and the corresponding d-isomers being inactive but able to antagonize inhibition by the l-isomers. Whereas not all connexins are sensitive to aminosulfonates, the well defined structural requirements described here argue strongly for a highly specific regulatory interaction with some connexins. The finding that cytoplasmic aminosulfonates inhibit connexin channels whereas other cytoplasmic compounds antagonize the inhibition suggests that gap junction channels are regulated by a complex interplay of cytoplasmic ligands.

  3. Mixing stream and datagram traffic on satellite: A FIFO Order-based Demand Assignment (FODA) Time Division Multiple Access (TDMA) scheme

    Science.gov (United States)

    Beltrame, R.; Bonito, A. B.; Celandroni, N.; Ferro, E.

    1985-11-01

    A FIFO Order based Demand Assignment (FODA) access scheme was designed to handle packetized data and voice traffic in a multiple access satellite broadcast channel of Mbits band. The channel is shared by as many as 64 simultaneously active stations in a range of 255 addressable stations. A sophisticated traffic environment is assumed, including different types of service requirements and an arbitrary load distribution among the stations. The results of 2Mbit/sec simulation tests for an existing hardware environment are presented.

  4. Models for Predictive Railway Traffic Management

    OpenAIRE

    Kecman, P.

    2014-01-01

    The potential growth in transport demand in the next decade and beyond requires a change from reactive to proactive traffic control to maintain and improve the reliability of railway traffic. In order to enable an anticipative approach to traffic management, it is necessary to develop the tools for monitoring, prediction and optimisation of the traffic operations. This thesis presents the models that can be used as components for a decision support system for predictive traffic management.

  5. tmc-1 encodes a sodium-sensitive channel required for salt chemosensation in C. elegans.

    Science.gov (United States)

    Chatzigeorgiou, Marios; Bang, Sangsu; Hwang, Sun Wook; Schafer, William R

    2013-02-01

    Transmembrane channel-like (TMC) genes encode a broadly conserved family of multipass integral membrane proteins in animals. Human TMC1 and TMC2 genes are linked to human deafness and required for hair-cell mechanotransduction; however, the molecular functions of these and other TMC proteins have not been determined. Here we show that the Caenorhabditis elegans tmc-1 gene encodes a sodium sensor that functions specifically in salt taste chemosensation. tmc-1 is expressed in the ASH polymodal avoidance neurons, where it is required for salt-evoked neuronal activity and behavioural avoidance of high concentrations of NaCl. However, tmc-1 has no effect on responses to other stimuli sensed by the ASH neurons including high osmolarity and chemical repellents, indicating a specific role in salt sensation. When expressed in mammalian cell culture, C. elegans TMC-1 generates a predominantly cationic conductance activated by high extracellular sodium but not by other cations or uncharged small molecules. Thus, TMC-1 is both necessary for salt sensation in vivo and sufficient to generate a sodium-sensitive channel in vitro, identifying it as a probable ionotropic sensory receptor. PMID:23364694

  6. Traffic Monitor

    Science.gov (United States)

    1992-01-01

    Mestech's X-15 "Eye in the Sky," a traffic monitoring system, incorporates NASA imaging and robotic vision technology. A camera or "sensor box" is mounted in a housing. The sensor detects vehicles approaching an intersection and sends the information to a computer, which controls the traffic light according to the traffic rate. Jet Propulsion Laboratory technical support packages aided in the company's development of the system. The X-15's "smart highway" can also be used to count vehicles on a highway and compute the number in each lane and their speeds, important information for freeway control engineers. Additional applications are in airport and railroad operations. The system is intended to replace loop-type traffic detectors.

  7. MPLS & Internet Traffic Engineering%MPLS和Internet流量工程

    Institute of Scientific and Technical Information of China (English)

    孟魁; 张根度

    2001-01-01

    Rapid growth of Internet traffic and increasing requirement for service quality have made traffic engineering an essential consideration in the operation of large Internet backbone networks. Historically,traffic engineering in the Internet has been hampered by the conventional IP technologies. This article discusses the challenge of Internet Traffic Engineering and the applications of MPLS to traffic engineering in IP networks.

  8. The Sodium-Activated Potassium Channel Slack Is Required for Optimal Cognitive Flexibility in Mice

    Science.gov (United States)

    Bausch, Anne E.; Dieter, Rebekka; Nann, Yvette; Hausmann, Mario; Meyerdierks, Nora; Kaczmarek, Leonard K.; Ruth, Peter; Lukowski, Robert

    2015-01-01

    "Kcnt1" encoded sodium-activated potassium channels (Slack channels) are highly expressed throughout the brain where they modulate the firing patterns and general excitability of many types of neurons. Increasing evidence suggests that Slack channels may be important for higher brain functions such as cognition and normal intellectual…

  9. An application of queueing theory to the design of channel requirements for special purpose communications satellites. Ph.D. Thesis

    Science.gov (United States)

    Hein, G. F.

    1974-01-01

    Special purpose satellites are very cost sensitive to the number of broadcast channels, usually will have Poisson arrivals, fairly low utilization (less than 35%), and a very high availability requirement. To solve the problem of determining the effects of limiting C the number of channels, the Poisson arrival, infinite server queueing model will be modified to describe the many server case. The model is predicated on the reproductive property of the Poisson distribution.

  10. Light signals for road traffic control.

    OpenAIRE

    Schreuder, D.A.

    1981-01-01

    Signals for road traffic control are a major constituent of the modern traffic scene, particularly in built-up areas. A vast amount of research has been executed in the last two decennia, resulting in a fairly generally accepted view on what the requirements for effective traffic lights are. For the French translation see B 19780

  11. Dynamic traffic grooming in survivable WDM networks

    Science.gov (United States)

    Zhu, Yonghua; Lin, Rujian

    2005-11-01

    This paper investigates the survivable traffic grooming problem for optical mesh networks employing wavelength-division multiplexing (WDM). While the transmission rate of a wavelength channel is high, the bandwidth requirement of a typical connection request can vary from the full wavelength capacity down to subwavelength. To efficiently utilize network resources, subwavelength-granularity connections can be groomed onto direct optical transmission channels, or lightpaths. Meanwhile, the failure of a network element can cause the failure of several lightpaths, thereby leading to large data and revenue loss. Fault-management schemes such as protection are essential to survive such failures. Different low-speed connections may request different bandwidth granularities as well as different protection schemes. How to efficiently groom such low-speed connections while satisfying their protection requirements is the main focus of our investigation. The paper tackles the dynamic survivable traffic grooming problems in multifiber wavelength-routed optical networks by representing the network as a layered graph model. This graph multi layers, where each layer represents a specific wavelength. Each link in the layered graph has more than one fibers and an associated cost. We use a modified Dijkstra algorithm that has a reduced complexity due to the structure of the layered graph. Heuristic algorithms for fiber selection based on a well-designed link-cost metrics are proposed. The performance of various routing algorithms is evaluated through simulation studies.

  12. 复杂业务需求下的光网络规划问题的研究%Study of optical network planning under complex traffic requirements

    Institute of Scientific and Technical Information of China (English)

    巩强; 曾凌; 徐世中; 王晟; 李乐民

    2011-01-01

    This paper studied optical network planning under complex traffic requirements.Formulated the planning problem into an integer linear programming( ILP), where supported connections or applications with different bandwidth requirements and protection requirements.Due to the very high computation complexity induced in solving the ILP for large networks, introduced Bender decomposition.Results show that using Bender decomposition can find the solution for large optical networks effectively, with much less time and memory consumptions.%研究了复杂业务需求下的光网络规划问题,建立了支持多种业务需求和保护需求的ILP数学模型;针对大型光网络相应的整数线性模型规模过大、难以求解的困难,引入了Bender数学分解方法.计算结果表明,利用Bender分解可以有效地求解复杂业务需求和保护需求下的光网络规划问题,同时降低时间和内存的消耗.

  13. Mechanotransduction in mouse inner ear hair cells requires transmembrane channel-like genes

    NARCIS (Netherlands)

    Kawashima, Yoshiyuki; Geleoc, Gwenaelle S. G.; Kurima, Kiyoto; Labay, Valentina; Lelli, Andrea; Asai, Yukako; Makishima, Tomoko; Wu, Doris K.; Della Santina, Charles C.; Holt, Jeffrey R.; Griffith, Andrew J.

    2011-01-01

    Inner ear hair cells convert the mechanical stimuli of sound, gravity, and head movement into electrical signals. This mechanotransduction process is initiated by opening of cation channels near the tips of hair cell stereocilia. Since the identity of these ion channels is unknown, and mutations in

  14. REQUIREMENTS OF MODERNIZATION ASSESSMENT AND MAINTENANCE OF THE NORTH CHANNEL OF OBRA

    Directory of Open Access Journals (Sweden)

    Paweł Kozaczyk

    2015-07-01

    Full Text Available In an attempt to assess the needs of the modernization of the North Channel of Obra, the construction began in 1852. The condition of drainage occurring on this course coming generally from the early 20th century and is unsatisfactory. This is the result of longstanding neglect and lack of maintenance. The first modernization works started in 1986. Undergoing on the North Channel of Obra are primarily made in the framework of four tasks, which was the regulation of the water course on a length of approximately 35 km 8 dams were built and 9 dams were demolished. The cost of upgrading the North Channel of The Obra was significantly different, what is the result of the works. They include the cost of reconstruction of the drainage channels, and the reconstruction of hydraulic structures. At this work, in addition to the needs assessment of the North Channel of Obra, further modernization needs were indicated.

  15. The β1-subunit of Na(v1.5 cardiac sodium channel is required for a dominant negative effect through α-α interaction.

    Directory of Open Access Journals (Sweden)

    Aurélie Mercier

    Full Text Available Brugada syndrome (BrS is an inherited autosomal dominant cardiac channelopathy. Several mutations on the cardiac sodium channel Na(v1.5 which are responsible for BrS lead to misfolded proteins that do not traffic properly to the plasma membrane. In order to mimic patient heterozygosity, a trafficking defective mutant, R1432G was co-expressed with Wild Type (WT Na(v1.5 channels in HEK293T cells. This mutant significantly decreased the membrane Na current density when it was co-transfected with the WT channel. This dominant negative effect did not result in altered biophysical properties of Na(v1.5 channels. Luminometric experiments revealed that the expression of mutant proteins induced a significant reduction in membrane expression of WT channels. Interestingly, we have found that the auxiliary Na channel β(1-subunit was essential for this dominant negative effect. Indeed, the absence of the β(1-subunit prevented the decrease in WT sodium current density and surface proteins associated with the dominant negative effect. Co-immunoprecipitation experiments demonstrated a physical interaction between Na channel α-subunits. This interaction occurred only when the β(1-subunit was present. Our findings reveal a new role for β(1-subunits in cardiac voltage-gated sodium channels by promoting α-α subunit interaction which can lead to a dominant negative effect when one of the α-subunits shows a trafficking defective mutation.

  16. Statistical Multiplexing of Video Traffic and Data Traffic

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper studies statistical multiplexing performance byinput of video traffic and data traffic. The inputs have different Qos requirements such as loss and delay jitter. By applying a modified FBM model, we present methods to estimate effective bandwidth of the aggregated traffic. Simulationswere paformed to evaluate effective bandwidth. The comparison between the estimation and the simulation shows that the estimations can give correct data for the effective bandwidths in terms of our interests. The analysis of gain by using priority multiplexing also addresses proper Qos configuration for the inputs in order to achieve positive gains.

  17. 47 CFR 80.325 - Control of distress traffic.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Control of distress traffic. 80.325 Section 80... Safety Procedures § 80.325 Control of distress traffic. (a) Distress traffic consists of all messages relating to the immediate assistance required by the mobile station in distress. In distress traffic,...

  18. Effect of Ad-Hoc Vehicular Network on Traffic Flow: Simulations in the Context of Three-Phase Traffic Theory

    OpenAIRE

    Kerner, B. S.; Klenov, S. L.; Brakemeier, A.

    2009-01-01

    Effects of vehicle-to-vehicle (or/and vehicle-to-infrastructure communication, called also V2X communication)on traffic flow, which are relevant for ITS, are numerically studied. To make the study adequate with real measured traffic data, a testbed for wireless vehicle communication based on a microscopic model in the framework of three-phase traffic theory is developed and discussed. In this testbed, vehicle motion in traffic flow and analyses of a vehicle communication channel access based ...

  19. Magnesium excretion in C. elegans requires the activity of the GTL-2 TRPM channel.

    Directory of Open Access Journals (Sweden)

    Takayuki Teramoto

    Full Text Available Systemic magnesium homeostasis in mammals is primarily governed by the activities of the TRPM6 and TRPM7 cation channels, which mediate both uptake by the intestinal epithelial cells and reabsorption by the distal convoluted tubule cells in the kidney. In the nematode, C. elegans, intestinal magnesium uptake is dependent on the activities of the TRPM channel proteins, GON-2 and GTL-1. In this paper we provide evidence that another member of the TRPM protein family, GTL-2, acts within the C. elegans excretory cell to mediate the excretion of excess magnesium. Thus, the activity of GTL-2 balances the activities of the paralogous TRPM channel proteins, GON-2 and GTL-1.

  20. Lost in traffic? The K+ channel of lily pollen, LilKT1, is detected at the endomembranes inside yeast cells, tobacco leaves and lily pollen

    Directory of Open Access Journals (Sweden)

    Minou Jasmin Safiarian

    2015-02-01

    Full Text Available Fertilization in plants relies on fast growth of pollen tubes through the style tissue towards the ovules. This polarized growth depends on influx of ions and water to increase the tube’s volume. K+ inward rectifying channels were detected in many pollen species, with one identified in Arabidopsis. Here, an Arabidopsis AKT1-like channel (LilKT1 was identified from Lilium longiflorum pollen. Complementation of K+ uptake deficient yeast mutants was only successful when the entire LilKT1 C-terminus was replaced by the AKT1 C-terminus. No signals were observed in the plasma membrane (PM of pollen tubes after expression of fluorescence-tagged LilKT1 nor were any LilKT1-derived peptides detectable in the pollen PM by mass spectrometry analysis. In contrast, fluorescent LilKT1 partly co-localized with the lily PM H+ ATPase LilHA2 in the PM of tobacco leaf cells, but exhibited a punctual fluorescence pattern and also sub-plasma membrane localization. Thus, incorporation of LilKT1 into the pollen PM seems tighter controlled than in other cells with still unknown trafficking signals in LilKT1’s C-terminus, resulting in channel densities below detection limits. This highly controlled incorporation might have physiological reasons: an uncontrolled number of K+ inward channels in the pollen PM will give an increased water influx due to the raising cytosolic K+ concentration, and finally, causing the tube to burst.

  1. Research on green channel system of first aid to highway traffic accident injury in Kunming city%昆明市军警联动高速公路急救绿色通道体系研究

    Institute of Scientific and Technical Information of China (English)

    刘军; 郝江; 边革元; 江岩

    2012-01-01

    Objective To study the current situation in the first aid of highway traffic accident injury in Kunming city, and to discuss and improve the first aid pattern through highway green channel established by the joint military and police. Methods Through the establishment of joint military and police first aid system, the coordination in calling emergency, sending an ambulance, field first aid,conveying,and hospitalized emergency care were specified by regulations and strengthened. Results Joint military and police green channel of highway first aid was superior to the traditional first aid system in the aspects of reaction time, successful rescue rate. Conclusion It is worthwhile to further promote the joint military and police green channel of highway first aid.%目的 研究昆明市高速公路交通伤急救的现状,探讨完善军警联动高速公路绿色通道急救模式.方法 通过设立紧急军警联动急救体系,在呼救协调、出车、现场急救、转运、院内抢救等方面给予制度规范及加强.结果 军警联动急救高速公路绿色通道在反应时间、抢救成功率上,均明显优于传统急救体系.结论 军警联动急救高速公路绿色通道值得进一步推广.

  2. Technical Documentation in Traffic Technology

    OpenAIRE

    Čurepić, Danko; Toš, Zdravko

    2009-01-01

    The requirements for the prompt usage of traffic infrastructure capacities define the technological frames which ensure updated maintenance and development of new traffic infrastructure capacities by implementing graphical and computer systems. Technical documentation (TD) based on the technology of geographic information systems (GIS) allows fast analysis of graphical and alphanumerical data with the aim of identifying spatial relations among various cartographic elements. The paper analyses...

  3. An organelle K+ channel is required for osmoregulation in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Xu, Feifei; Wu, Xiaoan; Jiang, Lin-Hua; Zhao, Hucheng; Pan, Junmin

    2016-08-01

    Fresh water protozoa and algae face hypotonic challenges in their living environment. Many of them employ a contractile vacuole system to uptake excessive water from the cytoplasm and expel it to the environment to achieve cellular homeostasis. K(+), a major osmolyte in contractile vacuole, is predicted to create higher osmolarity for water influx. Molecular mechanisms for K(+) permeation through the plasma membrane have been well studied. However, how K(+) permeates organelles such as the contractile vacuole is not clear. Here, we show that the six-transmembrane K(+) channel KCN11 in Chlamydomonas is exclusively localized to contractile vacuole. Ectopic expression of KCN11 in HEK293T cells results in voltage-gated K(+) channel activity. Disruption of the gene or mutation of key residues for K(+) permeability of the channel leads to dysfunction of cell osmoregulation in very hypotonic conditions. The contractile cycle is inhibited in the mutant cells with a slower rate of contractile vacuole swelling, leading to cell death. These data demonstrate a new role for six-transmembrane K(+) channels in contractile vacuole functioning and provide further insights into osmoregulation mediated by the contractile vacuole. PMID:27311484

  4. An organelle K+ channel is required for osmoregulation in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Xu, Feifei; Wu, Xiaoan; Jiang, Lin-Hua; Zhao, Hucheng; Pan, Junmin

    2016-08-01

    Fresh water protozoa and algae face hypotonic challenges in their living environment. Many of them employ a contractile vacuole system to uptake excessive water from the cytoplasm and expel it to the environment to achieve cellular homeostasis. K(+), a major osmolyte in contractile vacuole, is predicted to create higher osmolarity for water influx. Molecular mechanisms for K(+) permeation through the plasma membrane have been well studied. However, how K(+) permeates organelles such as the contractile vacuole is not clear. Here, we show that the six-transmembrane K(+) channel KCN11 in Chlamydomonas is exclusively localized to contractile vacuole. Ectopic expression of KCN11 in HEK293T cells results in voltage-gated K(+) channel activity. Disruption of the gene or mutation of key residues for K(+) permeability of the channel leads to dysfunction of cell osmoregulation in very hypotonic conditions. The contractile cycle is inhibited in the mutant cells with a slower rate of contractile vacuole swelling, leading to cell death. These data demonstrate a new role for six-transmembrane K(+) channels in contractile vacuole functioning and provide further insights into osmoregulation mediated by the contractile vacuole.

  5. The TRPM2 ion channel is required for sensitivity to warmth.

    Science.gov (United States)

    Tan, Chun-Hsiang; McNaughton, Peter A

    2016-08-25

    Thermally activated ion channels are known to detect the entire thermal range from extreme heat (TRPV2), painful heat (TRPV1, TRPM3 and ANO1), non-painful warmth (TRPV3 and TRPV4) and non-painful coolness (TRPM8) through to painful cold (TRPA1). Genetic deletion of each of these ion channels, however, has only modest effects on thermal behaviour in mice, with the exception of TRPM8, the deletion of which has marked effects on the perception of moderate coolness in the range 10-25 °C. The molecular mechanism responsible for detecting non-painful warmth, in particular, is unresolved. Here we used calcium imaging to identify a population of thermally sensitive somatosensory neurons which do not express any of the known thermally activated TRP channels. We then used a combination of calcium imaging, electrophysiology and RNA sequencing to show that the ion channel generating heat sensitivity in these neurons is TRPM2. Autonomic neurons, usually thought of as exclusively motor, also express TRPM2 and respond directly to heat. Mice in which TRPM2 had been genetically deleted showed a striking deficit in their sensation of non-noxious warm temperatures, consistent with the idea that TRPM2 initiates a 'warm' signal which drives cool-seeking behaviour. PMID:27533035

  6. The TRPM2 ion channel is required for sensitivity to warmth.

    Science.gov (United States)

    Tan, Chun-Hsiang; McNaughton, Peter A

    2016-08-25

    Thermally activated ion channels are known to detect the entire thermal range from extreme heat (TRPV2), painful heat (TRPV1, TRPM3 and ANO1), non-painful warmth (TRPV3 and TRPV4) and non-painful coolness (TRPM8) through to painful cold (TRPA1). Genetic deletion of each of these ion channels, however, has only modest effects on thermal behaviour in mice, with the exception of TRPM8, the deletion of which has marked effects on the perception of moderate coolness in the range 10-25 °C. The molecular mechanism responsible for detecting non-painful warmth, in particular, is unresolved. Here we used calcium imaging to identify a population of thermally sensitive somatosensory neurons which do not express any of the known thermally activated TRP channels. We then used a combination of calcium imaging, electrophysiology and RNA sequencing to show that the ion channel generating heat sensitivity in these neurons is TRPM2. Autonomic neurons, usually thought of as exclusively motor, also express TRPM2 and respond directly to heat. Mice in which TRPM2 had been genetically deleted showed a striking deficit in their sensation of non-noxious warm temperatures, consistent with the idea that TRPM2 initiates a 'warm' signal which drives cool-seeking behaviour.

  7. The foot structure from the type 1 ryanodine receptor is required for functional coupling to store-operated channels.

    Science.gov (United States)

    Sampieri, Alicia; Diaz-Muñoz, Mauricio; Antaramian, Anaid; Vaca, Luis

    2005-07-01

    In the present study we have explored structural determinants of the functional interaction between skeletal muscle ryanodine receptor (RyR1) and transient receptor potential channel 1 (TRPC1) channels expressed in Chinese hamster ovary cells. We have illustrated a functional interaction between TRPC1 channels and RyR1 for the regulation of store-operated calcium entry (SOCE) initiated after releasing calcium from a caffeine-sensitive intracellular calcium pool. RNA interference experiments directed to reduce the amount of TRPC1 protein indicate that RyR1 associates to at least two different types of store-operated channels (SOCs), one dependent and one independent of TRPC1. In contrast, bradykinin-induced SOCE is completely dependent on the presence of TRPC1 protein, as we have previously illustrated. Removing the foot structure from RyR1 results in normal caffeine-induced release of calcium from internal stores but abolishes the activation of SOCE, indicating that this structure is require for functional coupling to SOCs. The footless RyR1 protein shows a different cellular localization when compared with wild type RyR1. The later protein shows a higher percentage of colocalization with FM-464, a marker of plasma membrane. The implications of the foot structure for the functional and physical coupling to TRPC and SOCs is discussed.

  8. Phosphorylation of rat aquaporin-4 at Ser(111) is not required for channel gating

    DEFF Research Database (Denmark)

    Assentoft, Mette; Kaptan, Shreyas; Fenton, Robert A;

    2013-01-01

    is therefore of therapeutic interest. Phosphorylation of some aquaporins has been proposed to regulate their water permeability via gating of the channel itself. Protein kinase (PK)-dependent phosphorylation of Ser(111) has been reported to increase the water permeability of AQP4 expressed in an astrocytic......Aquaporin 4 (AQP4) is the predominant water channel in the mammalian brain and is mainly expressed in the perivascular glial endfeet at the brain-blood interface. AQP4 has been described as an important entry and exit site for water during formation of brain edema and regulation of AQP4...... cell line. This possibility was, however, questioned based on the crystal structure of the human AQP4. Our study aimed to resolve if Ser(111) was indeed a site involved in phosphorylation-mediated gating of AQP4. The water permeability of AQP4-expressing Xenopus oocytes was not altered by a range...

  9. The Effect of Channel Fading on Providing Quality

    Directory of Open Access Journals (Sweden)

    Marzieh Varposhti

    2008-09-01

    Full Text Available Transferring real-time traffic such as voice and video over wireless LAN network (WLAN requires stringent delay and jitter requirements. One of the methods to provide QoS in this standard is Enhanced Distributed Channel Access (EDCA which benefits form the concept of traffic categories. However, EDCA is a contention based method; therefore it can not guarantee strict QoS required by real-time services without proper network control mechanisms. One of the challenging problems in wireless networks is the failure of transmitting media due to fading. Normally the node does not differentiate between the media access collision and the channel failure. The performance of this method in case of fading channel has not yet been evaluated. In this paper, we analyze the effect of loss and delay caused by fading channel on EDCA performance. Then, we propose a modification to the media access scheme to elevate the performance against channel failures. Moreover an adjustment for the maximum number of retransmissions is proposed to maintain the delay and jitter requirements of the real-time traffic. The performances of the proposed methods are evaluated by simulations.

  10. Revolutionizing Technology Prioritizing Emergency Vehicles in Traffic

    Directory of Open Access Journals (Sweden)

    B. Ramya Sundaram

    2014-08-01

    Full Text Available The following study brings to the fore a technology exclusively engineered to eradicate the snags and inadequacies persisting in the existing system of traffic control and thus aims to provide a sophisticated operation and uninterrupted course for the emergency vehicles. The traffic in Indian roads has shown a tremendous rise over the years and the conventional pre-timed traffic signals and frequent traffic congestions, delaying the road commuters, have led to outrage and chaos on several occasions. This traffic management system has proved a nuisance for the effective operation of emergency vehicles, with the public adding to the woes, as each driver races along with the signal, unmindful of the emergency vehicles. A life threatening scenario ensues when emergency vehicles get blocked by the traffic, due to inefficient traffic management system and subsequently these emergency vehicles get delayed. The existing system requires manual interruption to guide other vehicles when an emergency vehicle passes through traffic junctions. It is therefore essential to implement a self-regulating and automated system in the traffic signals to facilitate smooth movement of emergency vehicles without posing a danger to other vehicles. The innovative traffic control system devised by us provides a truly dependable alternative to monitoring traffic flow when emergency vehicles pass by.

  11. Lead levels on traffic-less islands.

    Science.gov (United States)

    Elwood, P C; Blaney, R; Robb, R C; Essex-Cater, A J; Davies, B E; Toothill, C

    1985-09-01

    Surveys were conducted on three traffic-less islands: Tory and Aran, off the coast of Ireland, and Sark, one of the Channel Islands off the coast of France. Identical methods were used in surveys in three other areas, all of which have heavy gasoline driven traffic. These were Jersey, another of the Channel Islands, Ebbw Vale--a mixed industrial area, and Cardiff--the capital city of Wales. Environmental lead levels were very low in two of the traffic-less islands, but on the third, house dust lead levels were comparable with levels found throughout Wales. Blood lead levels on one of the islands were similar to those which have been reported for unaccultured remote tribes, but on the other two traffic-less islands blood lead levels were comparable with those of areas on the mainland of Wales.

  12. QoS Support Polling Scheme for Multimedia Traffic in Wireless LAN MAC Protocol

    Institute of Scientific and Technical Information of China (English)

    YANG Zhijun; ZHAO Dongfeng

    2008-01-01

    Quality of service (QoS) support is a key attribute for multimedia traffic including video, voice, and data in wireless local area networks (LANs) but is limited in 802.11-based wireless LANs. A polling-based scheme called the point coordination function (PCF) was developed for 802.11 LANs to support the trans-mission of multimedia traffic. However, the PCF is not able to meet the desired practical traffic differentiation requirements for real-time data. This paper describes a QoS support polling scheme based on the IEEE 802.11 medium access control (MAC) protocol. The scheme uses a two-level polling mechanism with the QoS classes differentiated by two different access policies. Stations with higher priority traffic such as key or real-time data form the first level and can access the common channel through an exhaustive access policy. Other stations with lower priority traffic form the second level and can access the channel through a gated access policy. A system model based on imbedded Markov chain theory and a generation function were setup to explicitly analyze the mean information packet waiting time of the two-level polling scheme. Theo-retical and simulation results show that the new scheme efficiently differentiates services to guarantee better QoS and system stability.

  13. Performance of a distributed DCA algorithm under inhomogeneous traffic modelled from an operational GSM network

    NARCIS (Netherlands)

    Kennedy, K.D.; Vries, E.T. de; Koorevaar, P.

    1998-01-01

    This paper presents results obtained from two different Dynamic Channel Allocation (DCA) algorithms, namely the Timid and Persistent Polite Aggressive (PPA) algorithms, simulated under both static homogeneous and dynamic inhomogeneous traffic. The dynamic inhomogeneous traffic is modelled upon real

  14. General requirement for harvesting antennae at Ca2+ and H+ channels and transporters

    Directory of Open Access Journals (Sweden)

    Cristián Martínez

    2010-09-01

    Full Text Available The production and dissipation of energy in cells is intimately linked to the movement of small molecules in and out of enzymes, channels and transporters. An analytical model of diffusion was described previously, which was used to estimate local effects of these proteins acting as molecular sources. The present article describes a simple but more general model, which can be used to estimate the local impact of proteins acting as molecular sinks. The results show that the enzymes, transporters and channels, whose substrates are present at relatively high concentrations like ATP, Na+, glucose, lactate and pyruvate, do not operate fast enough to deplete their vicinity to a meaningful extent, supporting the notion that for these molecules the cytosol is a well-mixed compartment. One specific consequence of this analysis is that the well-documented cross-talk existing between the Na+/K+ ATPase and the glycolytic machinery should not be explained by putative changes in local ATP concentration. In contrast, Ca2+ and H+ transporters like the Na+/Ca2+ exchanger NCX and the Na+/H+ exchanger NHE, show experimental rates of transport that are two to three orders of magnitude faster than the rates at which the aqueous phase may possibly feed their binding sites. This paradoxical result implies that Ca2+ and H+ transporters do not extract their substrates directly from the bulk cytosol, but from an intermediate “harvesting” compartment located between the aqueous phase and the transport site.

  15. Jamitons: Phantom Traffic Jams

    Science.gov (United States)

    Kowszun, Jorj

    2013-01-01

    Traffic on motorways can slow down for no apparent reason. Sudden changes in speed by one or two drivers can create a chain reaction that causes a traffic jam for the vehicles that are following. This kind of phantom traffic jam is called a "jamiton" and the article discusses some of the ways in which traffic engineers produce…

  16. A TRAFFIC OVERSTOCK RESLOVE SCHEME IN WLAN

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new Multiple Access Control (MAC) protocol-User Adaptive Scheduling Multiple Access (UASMA) protocol is proposed in this paper. It can well schedule the packet transmission according to the exact number of active Mobile Terminals (MTs) determined by selforganizing algorithm and adjust the number of packets sent by one node in one frame properly.UASMA protocol employs a special frame structure, which makes it possible to allocate channel resource to uplink and downlink traffic according to their respective service requirements. The proposed concept of referenced-frame-length can ensure the frame length varies in a certain range,and consequently increase the utilization efficiency of the channel greatly. Meanwhile, UASMA protocol uses an efficient collision resolution algorithm to guarantee that active MTs can access the channel rapidly. Finally, the performance of UASMA protocol is evaluated by simulation and it is also compared with carrier sense multiple access, rounding-poll and UPMA protocols. The results show that the UASMA has better performance than others.

  17. Side channel analysis of some hash based MACs:A response to SHA-3 requirements

    DEFF Research Database (Denmark)

    function which is more resistant to known side channel attacks (SCA) when plugged into HMAC, or that has an alternative MAC mode which is more resistant to known SCA than the other submitted alternatives. In response to this, we perform differential power analysis (DPA) on the possible smart card...... implementations of some of the recently proposed MAC alternatives to NMAC (a fully analyzed variant of HMAC) and HMAC algorithms and NMAC/HMAC versions of some recently proposed hash and compression function modes. We show that the recently proposed BNMAC and KMDP MAC schemes are even weaker than NMAC....../HMAC against the DPA attacks, whereas multi-lane NMAC, EMD MAC and the keyed wide-pipe hash have similar security to NMAC against the DPA attacks. Our DPA attacks do not work on the NMAC setting of MDC-2, Grindahl and MAME compression functions. This talk outlines our results....

  18. Side channel analysis of some hash based MACs: A response to SHA-3 requirements

    DEFF Research Database (Denmark)

    Gauravaram, Praveen; Okeya, Katsuyuki

    2008-01-01

    function which is more resistant to known side channel attacks (SCA) when plugged into HMAC, or that has an alternative MAC mode which is more resistant to known SCA than the other submitted alternatives. In response to this, we perform differential power analysis (DPA) on the possible smart card...... implementations of some of the recently proposed MAC alternatives to NMAC (a fully analyzed variant of HMAC) and HMAC algorithms and NMAC/HMAC versions of some recently proposed hash and compression function modes. We show that the recently proposed BNMAC and KMDP MAC schemes are even weaker than NMAC....../HMAC against the DPA attacks, whereas multi-lane NMAC, EMD MAC and the keyed wide-pipe hash have similar security to NMAC against the DPA attacks. Our DPA attacks do not work on the NMAC setting of MDC-2, Grindahl and MAME compression functions....

  19. CK2 activity is required for the interaction of FGF14 with voltage-gated sodium channels and neuronal excitability.

    Science.gov (United States)

    Hsu, Wei-Chun J; Scala, Federico; Nenov, Miroslav N; Wildburger, Norelle C; Elferink, Hannah; Singh, Aditya K; Chesson, Charles B; Buzhdygan, Tetyana; Sohail, Maveen; Shavkunov, Alexander S; Panova, Neli I; Nilsson, Carol L; Rudra, Jai S; Lichti, Cheryl F; Laezza, Fernanda

    2016-06-01

    Recent data shows that fibroblast growth factor 14 (FGF14) binds to and controls the function of the voltage-gated sodium (Nav) channel with phenotypic outcomes on neuronal excitability. Mutations in the FGF14 gene in humans have been associated with brain disorders that are partially recapitulated in Fgf14(-/-) mice. Thus, signaling pathways that modulate the FGF14:Nav channel interaction may be important therapeutic targets. Bioluminescence-based screening of small molecule modulators of the FGF14:Nav1.6 complex identified 4,5,6,7 -: tetrabromobenzotriazole (TBB), a potent casein kinase 2 (CK2) inhibitor, as a strong suppressor of FGF14:Nav1.6 interaction. Inhibition of CK2 through TBB reduces the interaction of FGF14 with Nav1.6 and Nav1.2 channels. Mass spectrometry confirmed direct phosphorylation of FGF14 by CK2 at S228 and S230, and mutation to alanine at these sites modified FGF14 modulation of Nav1.6-mediated currents. In 1 d in vitro hippocampal neurons, TBB induced a reduction in FGF14 expression, a decrease in transient Na(+) current amplitude, and a hyperpolarizing shift in the voltage dependence of Nav channel steady-state inactivation. In mature neurons, TBB reduces the axodendritic polarity of FGF14. In cornu ammonis area 1 hippocampal slices from wild-type mice, TBB impairs neuronal excitability by increasing action potential threshold and lowering firing frequency. Importantly, these changes in excitability are recapitulated in Fgf14(-/-) mice, and deletion of Fgf14 occludes TBB-dependent phenotypes observed in wild-type mice. These results suggest that a CK2-FGF14 axis may regulate Nav channels and neuronal excitability.-Hsu, W.-C. J., Scala, F., Nenov, M. N., Wildburger, N. C., Elferink, H., Singh, A. K., Chesson, C. B., Buzhdygan, T., Sohail, M., Shavkunov, A. S., Panova, N. I., Nilsson, C. L., Rudra, J. S., Lichti, C. F., Laezza, F. CK2 activity is required for the interaction of FGF14 with voltage-gated sodium channels and neuronal

  20. On traffic modelling in GPRS networks

    DEFF Research Database (Denmark)

    Madsen, Tatiana Kozlova; Schwefel, Hans-Peter; Prasad, Ramjee;

    2005-01-01

    Optimal design and dimensioning of wireless data networks, such as GPRS, requires the knowledge of traffic characteristics of different data services. This paper presents an in-detail analysis of an IP-level traffic measurements taken in an operational GPRS network. The data measurements reported...... here are done at the Gi interface. The aim of this paper is to reveal some key statistics of GPRS data applications and to validate if the existing traffic models can adequately describe traffic volume and inter-arrival time distribution for different services. Additionally, we present a method of user...

  1. An urban traffic extension of a freeway driver model for use in the OpenTraffic® open source traffic simulation

    NARCIS (Netherlands)

    Schakel, W.J.; Van Arem, B.

    2012-01-01

    This paper presents an extension of a microscopic freeway driver model for urban traffic. As urban traffic is more complex than freeway traffic, and because scientific models require extensive development, scientific models are often limited to freeways. For urban studies commercial software is ofte

  2. HYBRID INTERNET TRAFFIC CLASSIFICATION TECHNIQUE1

    Institute of Scientific and Technical Information of China (English)

    Li Jun; Zhang Shunyi; Lu Yanqing; Yan Junrong

    2009-01-01

    Accurate and real-time classification of network traffic is significant to network operation and management such as QoS differentiation, traffic shaping and security surveillance. However, with many newly emerged P2P applications using dynamic port numbers, masquerading techniques, and payload encryption to avoid detection, traditional classification approaches turn to be ineffective. In this paper, we present a layered hybrid system to classify current Internet traffic, motivated by variety of network activities and their requirements of traffic classification. The proposed method could achieve fast and accurate traffic classification with low overheads and robustness to accommodate both known and unknown/encrypted applications. Furthermore, it is feasible to be used in the context of real-time traffic classification. Our experimental results show the distinct advantages of the proposed classification system, compared with the one-step Machine Learning (ML) approach.

  3. Activation of L-type calcium channels is required for gap junction-mediated intercellular calcium signaling in osteoblastic cells

    Science.gov (United States)

    Jorgensen, Niklas Rye; Teilmann, Stefan Cuoni; Henriksen, Zanne; Civitelli, Roberto; Sorensen, Ole Helmer; Steinberg, Thomas H.

    2003-01-01

    The propagation of mechanically induced intercellular calcium waves (ICW) among osteoblastic cells occurs both by activation of P2Y (purinergic) receptors by extracellular nucleotides, resulting in "fast" ICW, and by gap junctional communication in cells that express connexin43 (Cx43), resulting in "slow" ICW. Human osteoblastic cells transmit intercellular calcium signals by both of these mechanisms. In the current studies we have examined the mechanism of slow gap junction-dependent ICW in osteoblastic cells. In ROS rat osteoblastic cells, gap junction-dependent ICW were inhibited by removal of extracellular calcium, plasma membrane depolarization by high extracellular potassium, and the L-type voltage-operated calcium channel inhibitor, nifedipine. In contrast, all these treatments enhanced the spread of P2 receptor-mediated ICW in UMR rat osteoblastic cells. Using UMR cells transfected to express Cx43 (UMR/Cx43) we confirmed that nifedipine sensitivity of ICW required Cx43 expression. In human osteoblastic cells, gap junction-dependent ICW also required activation of L-type calcium channels and influx of extracellular calcium.

  4. A Marine Traffic Flow Model

    OpenAIRE

    Tsz Leung Yip

    2013-01-01

    A model is developed for studying marine traffic flow through classical traffic flow theories, which can provide us with a better understanding of the phenomenon of traffic flow of ships. On one hand, marine traffic has its special features and is fundamentally different from highway, air and pedestrian traffic. The existing traffic models cannot be simply extended to marine traffic without addressing marine traffic features. On the other hand, existing literature on marine traffic focuses on...

  5. SELF-SIMILAR TRAFFIC GENERATOR

    OpenAIRE

    Linawati Linawati; I Made Suartika

    2009-01-01

    Network traffic generator can be produced using OPNET. OPNET generates the traffic as explicit traffic or background traffic. This paper demonstrates generating traffic in OPNET 7.0 as background traffic. The traffi generator that was simulated is self-similar traffic with different Hurst parameter. The simulation results proved that OPNET with background traffic function can be as a qualified self-similar traffic generator. These results can help in investigating and analysing network perfor...

  6. The H-loop in the Second Nucleotide-binding Domain of the Cystic Fibrosis Transmembrane Conductance Regulator is Required for Efficient Chloride Channel Closing

    OpenAIRE

    Kloch, Monika; Milewski, Michał; Nurowska, Ewa; Dworakowska, Beata; Cutting, Garry R; Dołowy, Krzysztof

    2010-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a cAMP-activated chloride channel. The recent model of CFTR gating predicts that the ATP binding to both nucleotide-binding domains (NBD1 and NBD2) of CFTR is required for the opening of the channel, while the ATP hydrolysis at NBD2 induces subsequent channel closing. In most ABC proteins, efficient hydrolysis of ATP requires the presence of the invariant histidine res...

  7. A Survey on the Common Network Traffic Sources Models

    Directory of Open Access Journals (Sweden)

    Ahmed M. Mohammed

    2011-05-01

    Full Text Available Selecting the appropriate traffic model can lead to successful design of computer networks. Themore accurate the traffic model is the better the system quantified in terms of its performance.Successful design leads to enhancement the overall performance of the whole of network. Inliterature, there is innumerous traffic models proposed for understanding and analyzing the trafficcharacteristics of computer networks. Consequently, the study of traffic models to understand thefeatures of the models and identify eventually the best traffic model, for a concerned environmenthas become a crucial and lucrative task. Good traffic modeling is also a basic requirement foraccurate capacity planning. This paper provides an overview of some of the widely used networktraffic models, highlighting the core features of these models and traffic characteristics. Finally wefound that the N_BURST traffic model can capture the traffic characteristics of most types ofcomputer networks.

  8. An efficient method to detect periodic behavior in botnet traffic by analyzing control plane traffic

    Science.gov (United States)

    AsSadhan, Basil; Moura, José M.F.

    2013-01-01

    Botnets are large networks of bots (compromised machines) that are under the control of a small number of bot masters. They pose a significant threat to Internet’s communications and applications. A botnet relies on command and control (C2) communications channels traffic between its members for its attack execution. C2 traffic occurs prior to any attack; hence, the detection of botnet’s C2 traffic enables the detection of members of the botnet before any real harm happens. We analyze C2 traffic and find that it exhibits a periodic behavior. This is due to the pre-programmed behavior of bots that check for updates to download them every T seconds. We exploit this periodic behavior to detect C2 traffic. The detection involves evaluating the periodogram of the monitored traffic. Then applying Walker’s large sample test to the periodogram’s maximum ordinate in order to determine if it is due to a periodic component or not. If the periodogram of the monitored traffic contains a periodic component, then it is highly likely that it is due to a bot’s C2 traffic. The test looks only at aggregate control plane traffic behavior, which makes it more scalable than techniques that involve deep packet inspection (DPI) or tracking the communication flows of different hosts. We apply the test to two types of botnet, tinyP2P and IRC that are generated by SLINGbot. We verify the periodic behavior of their C2 traffic and compare it to the results we get on real traffic that is obtained from a secured enterprise network. We further study the characteristics of the test in the presence of injected HTTP background traffic and the effect of the duty cycle on the periodic behavior. PMID:25685512

  9. Channel Power in Multi-Channel Environments

    NARCIS (Netherlands)

    M.G. Dekimpe (Marnik); B. Skiera (Bernd)

    2004-01-01

    textabstractIn the literature, little attention has been paid to instances where companies add an Internet channel to their direct channel portfolio. However, actively managing multiple sales channels requires knowing the customers’ channel preferences and the resulting channel power. Two key compon

  10. Traffic Flow Theory

    OpenAIRE

    Maerivoet, Sven; De Moor, Bart

    2005-01-01

    The scientific field of traffic engineering encompasses a rich set of mathematical techniques, as well as researchers with entirely different backgrounds. This paper provides an overview of what is currently the state-of-the-art with respect to traffic flow theory. Starting with a brief history, we introduce the microscopic and macroscopic characteristics of vehicular traffic flows. Moving on, we review some performance indicators that allow us to assess the quality of traffic operations. A f...

  11. Optimizing Traffic Flow

    OpenAIRE

    Huberman, Bernardo A.; Helbing, Dirk

    1998-01-01

    We present an economics-based method for deciding the optimal rates at which vehicles are allowed to enter a highway. The method exploits the naturally occuring fluctuations of traffic flow and is flexible enough to adapt in real time to the transient flow characteristics of road traffic. Simulations based on realistic parameter values show that this strategy is feasible for naturally occuring traffic, and that even far from optimality, injection policies can improve traffic flow. Our results...

  12. Traffic-flow simulation

    OpenAIRE

    OMAHEN, ANDRAŽ

    2015-01-01

    This diploma thesis presents the behavior of program, which uses the traffic light enhanced transport network to simulate the traffic flow of vehicles that behave according to the IDM model. We upgraded the program to allow, for the given network, to optimize the traffic flow. Because of the overwhelming problem of road closures or their rearrangement, we added a graphical user interface with which a user can create or modify the road network to observe changes in traffic. The objective of...

  13. 32 CFR 636.11 - Installation traffic codes

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Installation traffic codes 636.11 Section 636.11... CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION (SPECIFIC INSTALLATIONS) Fort Stewart, Georgia § 636.11 Installation traffic codes In addition to the requirements in § 634.25(d) of this...

  14. 14 CFR 213.2 - Reports of traffic data.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Reports of traffic data. 213.2 Section 213... traffic data. The Department may at any time require any foreign air carrier to file with the Department traffic data disclosing the nature and extent of such carrier's engagement in transportation...

  15. Traffic Flow Estimates.

    Science.gov (United States)

    Hart, Vincent G.

    1981-01-01

    Two examples are given of ways traffic engineers estimate traffic flow. The first, Floating Car Method, involves some basic ideas and the notion of relative velocity. The second, Maximum Traffic Flow, is viewed to involve simple applications of calculus. The material provides insight into specialized applications of mathematics. (MP)

  16. Learning Behavior Models for Interpreting and Predicting Traffic Situations

    OpenAIRE

    Gindele, Tobias

    2014-01-01

    In this thesis, we present Bayesian state estimation and machine learning methods for predicting traffic situations. The cognitive ability to assess situations and behaviors of traffic participants, and to anticipate possible developments is an essential requirement for several applications in the traffic domain, especially for self-driving cars. We present a method for learning behavior models from unlabeled traffic observations and develop improved learning methods for decision trees.

  17. Measures related to traffic planning for air pollution control

    Energy Technology Data Exchange (ETDEWEB)

    Baumueller, J.; Reuter, U. [Office of Environmental Protection, Stuttgart (Germany). Dept. for Climatology

    1995-12-31

    The immense increase of motor traffic, in the future reinforced by the European market and the opening of boarders to the east countries, requires new efforts in traffic policy. In the city agglomerations the motor traffic is nearly collapsing. The increase of motor traffic is the reason for a considerable degradation of environment, especially by noise and air pollution. For the region of Stuttgart the problems and possibilities of counter-measures are discussed. (author)

  18. Fault Node Accurately Mining Algorithm Based on Traffic Channel Carrier Balance%正交通信信道载波均衡故障节点准确挖掘算法

    Institute of Scientific and Technical Information of China (English)

    张海霞

    2015-01-01

    Construction of accurate positioning and detection of cloud server fault fast mining model of fault node in large-scale cloud computing is important. In the traditional method, using the protocol stack of constraint and management of node, achieve the fault node fast mining purposes, the algorithm is deployed in the position of the Sink node is not properly considered, it is easy to neighboring nodes overlap between channels in the transmission spectrum of main lobe, and fault node mining is not good. Aiming at this problem, a method to calculate the Federation server fault is the traffic channel car⁃rier equilibrium cloud is proposed based on fast mining algorithm, a node fault information fusion model is obtained, the characteristic analysis of the information is taken, the fusion process is taken, the new cloud computing server receiving end and the transmitting end fault localization training sequence mining, the equivalent baseband model of fault node based on OFDM system is constructed, the communication channel carrier is balanced in fast mining cloud server failure node. The simulation results show that, the algorithm can realize the accurate location of fault node, mining performance is good, probability of detection is increased, it is superior to the traditional model.%大型云计算联合服务器中故障节点的快速挖掘模型构建可以实现对云服务器故障的准确定位和检测。传统方法中采用协议堆栈对节点进行约束与管理,达到故障节点快速挖掘的目的,然而该算法在Sink节点位置部署考虑欠好,在通信传输中很容易相邻节点信道间频谱主瓣重叠,故障节点挖掘性能不好。针对这一问题,提出一种基于正交通信信道载波均衡的云计算联合服务器故障节点快速挖掘算法,建立故障节点信息融合模型,进行特征分析,在信息融合过程中,组成新的云计算联合服务器接收端和发射端故障节点定位训练

  19. A digital simulation of message traffic for natural disaster warning communications satellite

    Science.gov (United States)

    Hein, G. F.; Stevenson, S. M.

    1972-01-01

    Various types of weather communications are required to alert industries and the general public about the impending occurrence of tornados, hurricanes, snowstorms, floods, etc. A natural disaster warning satellite system has been proposed for meeting the communications requirements of the National Oceanic and Atmospheric Administration. Message traffic for a communications satellite was simulated with a digital computer in order to determine the number of communications channels to meet system requirements. Poisson inputs are used for arrivals and an exponential distribution is used for service.

  20. Modelling the Traffic System

    Directory of Open Access Journals (Sweden)

    Važan Pavel

    2014-12-01

    Full Text Available The paper presents the simulation study results of the traffic system in the city of Hlohovec. The authors describe the process of building the model in Witness 2013c simulator. The individual entities of simulation model are explained in details, as the Witness simulator is primarily suitable for manufacture or service simulation and not for traffic system simulation. The goal of this paper is to analyse the traffic system and to suggest the changes for improving the traffic in the city of Hlohovec. All proposed measures will bring about 20% improvement of traffic when compared to the current state.

  1. Shal/K(v4 channels are required for maintaining excitability during repetitive firing and normal locomotion in Drosophila.

    Directory of Open Access Journals (Sweden)

    Yong Ping

    Full Text Available BACKGROUND: Rhythmic behaviors, such as walking and breathing, involve the coordinated activity of central pattern generators in the CNS, sensory feedback from the PNS, to motoneuron output to muscles. Unraveling the intrinsic electrical properties of these cellular components is essential to understanding this coordinated activity. Here, we examine the significance of the transient A-type K(+ current (I(A, encoded by the highly conserved Shal/K(v4 gene, in neuronal firing patterns and repetitive behaviors. While I(A is present in nearly all neurons across species, elimination of I(A has been complicated in mammals because of multiple genes underlying I(A, and/or electrical remodeling that occurs in response to affecting one gene. METHODOLOGY/PRINCIPAL FINDINGS: In Drosophila, the single Shal/K(v4 gene encodes the predominant I(A current in many neuronal cell bodies. Using a transgenically expressed dominant-negative subunit (DNK(v4, we show that I(A is completely eliminated from cell bodies, with no effect on other currents. Most notably, DNK(v4 neurons display multiple defects during prolonged stimuli. DNK(v4 neurons display shortened latency to firing, a lower threshold for repetitive firing, and a progressive decrement in AP amplitude to an adapted state. We record from identified motoneurons and show that Shal/K(v4 channels are similarly required for maintaining excitability during repetitive firing. We then examine larval crawling, and adult climbing and grooming, all behaviors that rely on repetitive firing. We show that all are defective in the absence of Shal/K(v4 function. Further, knock-out of Shal/K(v4 function specifically in motoneurons significantly affects the locomotion behaviors tested. CONCLUSIONS/SIGNIFICANCE: Based on our results, Shal/K(v4 channels regulate the initiation of firing, enable neurons to continuously fire throughout a prolonged stimulus, and also influence firing frequency. This study shows that Shal/K(v4

  2. Classification and Analysis of Computer Network Traffic

    DEFF Research Database (Denmark)

    Bujlow, Tomasz

    2014-01-01

    to create realistic traffic profiles of the selected applications, which can server as the training data for MLAs. We assessed the usefulness of C5.0 Machine Learning Algorithm (MLA) in the classification of computer network traffic. We showed that the application-layer payload is not needed to train the C5...... various classification modes (decision trees, rulesets, boosting, softening thresholds) regarding the classification accuracy and the time required to create the classifier. We showed how to use our VBS tool to obtain per-flow, per-application, and per-content statistics of traffic in computer networks......Traffic monitoring and analysis can be done for multiple different reasons: to investigate the usage of network resources, assess the performance of network applications, adjust Quality of Service (QoS) policies in the network, log the traffic to comply with the law, or create realistic models...

  3. Impact of Traffic Sign on Pedestrians’ Walking Behavior

    OpenAIRE

    Hui Xiong; Pingfu Yao; Xuedong Guo; Chenglong Chu; Wuhong Wang

    2015-01-01

    To study the impact of traffic sign on pedestrian walking behavior, the paper applies cellular automaton to simulate one-way pedestrian flow. The channel is defined as a rectangle with one open entrance and two exits of equal width. Traffic sign showing that exit is placed with some distance in the middle front of the two exits. In the simulation, walking environment is set with various input density, width of exit, width and length of the channel, and distance of the traffic sign to exit. Si...

  4. Implications of traffic characteristics on interdomain traffic engineering

    OpenAIRE

    Uhlig, Steve

    2004-01-01

    This thesis discusses the implications of the traffic characteristics on interdomain traffic engineering with BGP. We first provide an overview of the interdomain traffic control problem. Then, we present results concerning the characteristics of the interdomain traffic, based on the analysis of real traffic traces gathered from non-transit ASes. We discuss the implications of the topological properties of the traffic on interdomain traffic engineering. Based on this knowledge of the...

  5. Study on Rural Poverty Reduction Effect of Traffic Infrastructure

    Institute of Scientific and Technical Information of China (English)

    Junping; GUO; Bin; ZHANG; Xiyan; ZHANG

    2014-01-01

    To systematically comb and explore the rural poverty reduction effect of traffic infrastructure,the author analyzed the mechanism,main channels and actual effect of rural traffic infrastructure on poverty reduction.It revealed that rural traffic infrastructure exerts positive or negative effect on poverty reduction directly or indirectly.The positive channel includes increasing non-agricultural employment opportunities,reducing costs for agricultural production,transportation and labor transfer,increasing availability of social service,and promoting adjustment of agricultural industrial structure and development of rural tourism resources.On the whole,traffic infrastructure has significant positive influence on rural poverty reduction.Finally,it summarized policy recommendations for building pro-poor traffic infrastructure,and came up with vacancy of related research field and future exploration direction.

  6. Trajectory Based Traffic Analysis

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin;

    2013-01-01

    We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point-and-click a......We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point......-and-click analysis, due to a novel and efficient indexing structure. With the web-site daisy.aau.dk/its/spqdemo/we will demonstrate several analyses, using a very large real-world data set consisting of 1.9 billion GPS records (1.5 million trajectories) recorded from more than 13000 vehicles, and touching most...

  7. Internet Traffic Engineering

    OpenAIRE

    Bonaventure, Olivier; Trimintzios, Panos; Pavlou, George; Quoitin, Bruno; Azcorra, Arturo; Bagnulo, Marcelo; Fegkas, Paris; García-Martínez, Alberto; Georgatsos, Panos; Georgiadis, Leonidas; Jacquenet, Christian; Swinnen, Louis; Tandel, Sebastien; Uhlig, Steve

    2004-01-01

    Traffic engineering encompasses a set of techniques that can be used to control the flow of traffic in data networks. We discuss several of those techniques that have been developed during the last few years. Some techniques are focused on pure IP networks while others have been designed with emerging technologies for scalable Quality of Service (QoS) such as Differentiated Services and MPLS in mind. We first discuss traffic engineering techniques inside a single domain. We show that by using...

  8. Distraction in traffic.

    OpenAIRE

    2013-01-01

    Many drivers, as well as cyclists and pedestrians, are occupied with all kinds of activities that can distract their attention from traffic, like listening to music, conducting a conversation on their mobile phone, or texting. Distraction has negative effects on traffic behaviour. Most studies estimate that distraction plays a role in the occurrence of about 5-25% of the car crashes. Considering the increasing diffusion of electronic devices in traffic, portable media devices as well as advan...

  9. Traffic Signs Inventory System

    Directory of Open Access Journals (Sweden)

    J. Ružbarský

    2013-06-01

    Full Text Available The paper is focused on practical application of Cambridge Correlator. The goal is to propose a traffic signs inventory system by using excellent characteristics of correlator in the rapid optical correlation. The proposal of this inventory system includes obtaining of traffic signs to create the database either collecting the GPS coordinates. It is necessary to know the traffic signs position and also to document the entire surface route for later evaluation in offline mode.

  10. Using memory for prior aircraft events to detect conflicts under conditions of proactive air traffic control and with concurrent task requirements.

    Science.gov (United States)

    Bowden, Vanessa K; Loft, Shayne

    2016-06-01

    In 2 experiments we examined the impact of memory for prior events on conflict detection in simulated air traffic control under conditions where individuals proactively controlled aircraft and completed concurrent tasks. Individuals were faster to detect conflicts that had repeatedly been presented during training (positive transfer). Bayesian statistics indicated strong evidence for the null hypothesis that conflict detection was not impaired for events that resembled an aircraft pair that had repeatedly come close to conflicting during training. This is likely because aircraft altitude (the feature manipulated between training and test) was attended to by participants when proactively controlling aircraft. In contrast, a minor change to the relative position of a repeated nonconflicting aircraft pair moderately impaired conflict detection (negative transfer). There was strong evidence for the null hypothesis that positive transfer was not impacted by dividing participant attention, which suggests that part of the information retrieved regarding prior aircraft events was perceptual (the new aircraft pair "looked" like a conflict based on familiarity). These findings extend the effects previously reported by Loft, Humphreys, and Neal (2004), answering the recent strong and unanimous calls across the psychological science discipline to formally establish the robustness and generality of previously published effects. (PsycINFO Database Record PMID:27295467

  11. PTSD in post-road traffic accident patients requiring hospitalization in Indian subcontinent: A review on magnitude of the problem and management guidelines.

    Science.gov (United States)

    Undavalli, Chaitanya; Das, Piyush; Dutt, Taru; Bhoi, Sanjeev; Kashyap, Rahul

    2014-10-01

    Traumatic events after a road traffic accident (RTA) can be physical and/or psychological. Posttraumatic stress disorder (PTSD) is one of the major psychological conditions which affect accident victims. Psychological issues may not be addressed in the emergency department(ED) immediately. There have been reports about a mismatch between the timely referrals from ED to occupational or primary care services for these issues. If left untreated, there may be adverse effects on quality of life (QOL) and work productivity. Hospital expenses, loss of income, and loss of work could create a never ending cycle for financial difficulties and burden in trauma victims. The aim of our review is to address the magnitude of PTSD in post-RTA hospitalized patients in Indian subcontinent population. We also attempted to emphasis on few management guidelines. A comprehensive search was conducted on major databases with Medical Subject Headings (MeSH) term 'PTSD or post-traumatic stress' and Emergency department and vehicle or road or highway or automobile or car or truck or trauma and India. Out of 120 studies, a total of six studies met our inclusion criteria and were included in the review. Our interpretation of the problem is that; hospital expenditure due to trauma, time away from work during hospitalization, and reduction in work performance, are three major hits that can lead RTA victims to financial crisis. Proposed management guidelines are; establish a coordinated triage, implementing a screening tool in the ED, and provide psychological counseling.

  12. PTSD in post-road traffic accident patients requiring hospitalization in Indian subcontinent: A review on magnitude of the problem and management guidelines

    Directory of Open Access Journals (Sweden)

    Chaitanya Undavalli

    2014-01-01

    Full Text Available Traumatic events after a road traffic accident (RTA can be physical and/or psychological. Posttraumatic stress disorder (PTSD is one of the major psychological conditions which affect accident victims. Psychological issues may not be addressed in the emergency department(ED immediately. There have been reports about a mismatch between the timely referrals from ED to occupational or primary care services for these issues. If left untreated, there may be adverse effects on quality of life (QOL and work productivity. Hospital expenses, loss of income, and loss of work could create a never ending cycle for financial difficulties and burden in trauma victims. The aim of our review is to address the magnitude of PTSD in post-RTA hospitalized patients in Indian subcontinent population. We also attempted to emphasis on few management guidelines. A comprehensive search was conducted on major databases with Medical Subject Headings (MeSH term ′PTSD or post-traumatic stress′ and Emergency department and vehicle or road or highway or automobile or car or truck or trauma and India. Out of 120 studies, a total of six studies met our inclusion criteria and were included in the review. Our interpretation of the problem is that; hospital expenditure due to trauma, time away from work during hospitalization, and reduction in work performance, are three major hits that can lead RTA victims to financial crisis. Proposed management guidelines are; establish a coordinated triage, implementing a screening tool in the ED, and provide psychological counseling.

  13. Requirement of subunit co-assembly and ankyrin-G for M-channel localization at the axon initial segment

    DEFF Research Database (Denmark)

    Rasmussen, Hanne B; Frøkjaer-Jensen, Christian; Jensen, Camilla Stampe;

    2007-01-01

    The potassium channel subunits KCNQ2 and KCNQ3 are believed to underlie the M current of hippocampal neurons. The M-type potassium current plays a key role in the regulation of neuronal excitability; however, the subcellular location of the ion channels underlying this regulation has been controv...

  14. Slack sodium-activated potassium channel membrane expression requires p38 mitogen-activated protein kinase phosphorylation.

    Science.gov (United States)

    Gururaj, Sushmitha; Fleites, John; Bhattacharjee, Arin

    2016-04-01

    p38 MAPK has long been understood as an inducible kinase under conditions of cellular stress, but there is now increasing evidence to support its role in the regulation of neuronal function. Several phosphorylation targets have been identified, an appreciable number of which are ion channels, implicating the possible involvement of p38 MAPK in neuronal excitability. The KNa channel Slack is an important protein to be studied as it is highly and ubiquitously expressed in DRG neurons and is important in the maintenance of their firing accommodation. We sought to examine if the Slack channel could be a substrate of p38 MAPK activity. First, we found that the Slack C-terminus contains two putative p38 MAPK phosphorylation sites that are highly conserved across species. Second, we show via electrophysiology experiments that KNa currents and further, Slack currents, are subject to tonic modulation by p38 MAPK. Third, biochemical approaches revealed that Slack channel regulation by p38 MAPK occurs through direct phosphorylation at the two putative sites of interaction, and mutating both sites prevented surface expression of Slack channels. Based on these results, we conclude that p38 MAPK is an obligate regulator of Slack channel function via the trafficking of channels into the membrane. The present study identifies Slack KNa channels as p38 MAPK substrates. PMID:26721627

  15. The L-type calcium channel Cav1.3 is required for proper hippocampal neurogenesis and cognitive functions.

    Science.gov (United States)

    Marschallinger, Julia; Sah, Anupam; Schmuckermair, Claudia; Unger, Michael; Rotheneichner, Peter; Kharitonova, Maria; Waclawiczek, Alexander; Gerner, Philipp; Jaksch-Bogensperger, Heidi; Berger, Stefan; Striessnig, Jörg; Singewald, Nicolas; Couillard-Despres, Sebastien; Aigner, Ludwig

    2015-12-01

    L-type voltage gated Ca(2+) channels (LTCCs) are widely expressed within different brain regions including the hippocampus. The isoforms Cav1.2 and Cav1.3 have been shown to be involved in hippocampus-dependent learning and memory, cognitive functions that require proper hippocampal neurogenesis. In vitro, functional LTCCs are expressed on neuronal progenitor cells, where they promote neuronal differentiation. Expression of LTCCs on neural stem and progenitor cells within the neurogenic regions in the adult brain in vivo has not been examined so far, and a contribution of the individual isoforms Cav1.2 and Cav1.3 to adult neurogenesis remained to be clarified. To reveal the role of these channels we first evaluated the expression patterns of Cav1.2 and Cav1.3 in the hippocampal dentate gyrus and the subventricular zone (SVZ) in adult (2- and 3-month old) and middle-aged (15-month old) mice on mRNA and protein levels. We performed immunohistological analysis of hippocampal neurogenesis in adult and middle-aged Cav1.3(-/-) mice and finally addressed the importance of Cav1.3 for hippocampal function by evaluating spatial memory and depression-like behavior in adult Cav1.3(-/-) mice. Our results showed Cav1.2 and Cav1.3 expression at different stages of neuronal differentiation. While Cav1.2 was primarily restricted to mature NeuN(+) granular neurons, Cav1.3 was expressed in Nestin(+) neural stem cells and in mature NeuN(+) granular neurons. Adult and middle-aged Cav1.3(-/-) mice showed severe impairments in dentate gyrus neurogenesis, with significantly smaller dentate gyrus volume, reduced survival of newly generated cells, and reduced neuronal differentiation. Further, Cav1.3(-/-) mice showed impairment in the hippocampus dependent object location memory test, implicating Cav1.3 as an essential element for hippocampus-associated cognitive functions. Thus, modulation of LTCC activities may have a crucial impact on neurogenic responses and cognition, which should be

  16. Visual Analysis of Air Traffic Data

    Science.gov (United States)

    Albrecht, George Hans; Pang, Alex

    2012-01-01

    In this paper, we present visual analysis tools to help study the impact of policy changes on air traffic congestion. The tools support visualization of time-varying air traffic density over an area of interest using different time granularity. We use this visual analysis platform to investigate how changing the aircraft separation volume can reduce congestion while maintaining key safety requirements. The same platform can also be used as a decision aid for processing requests for unmanned aerial vehicle operations.

  17. Distraction in traffic.

    NARCIS (Netherlands)

    2013-01-01

    Many drivers, as well as cyclists and pedestrians, are occupied with all kinds of activities that can distract their attention from traffic, like listening to music, conducting a conversation on their mobile phone, or texting. Distraction has negative effects on traffic behaviour. Most studies estim

  18. Costs of traffic injuries

    DEFF Research Database (Denmark)

    Kruse, Marie

    2015-01-01

    assessed using Danish national healthcare registers. Productivity costs were computed using duration analysis (Cox regression models). In a subanalysis, cost per severe traffic injury was computed for the 12 995 individuals that experienced a severe injury. RESULTS: The socioeconomic cost of a traffic...

  19. The Traffic Light Challenge

    Science.gov (United States)

    Roman, Harry T.

    2014-01-01

    Traffic lights are an important part of the transportation infrastructure, regulating traffic flow and maintaining safety when crossing busy streets. When they go awry or become nonfunctional, a great deal of havoc and danger can be present. During power outages, the street lights go out all over the affected area. It would be good to be able to…

  20. Road Traffic in China

    NARCIS (Netherlands)

    Jie, L.; Van Zuylen, H.J.

    2014-01-01

    Traffic is tightly related to the social and economic development in a country. In China the development of the economy has been very fast in the past 30 years and this is still continuing. The transport infrastructure shows a similar pattern, while traffic is also rapidly growing. In urban areas th

  1. Controlled Traffic Farming

    OpenAIRE

    Controlled Traffic Farming Europe

    2011-01-01

    Metadata only record Controlled Traffic Farming (CTF) is a farming method used to reduce soil compaction, decrease inputs, and improve soil structure when coupled with reduced-till or no-till practices. This practices utilizes permanent traffic/wheel zones to limit soil compaction to a specific area. This website provides practical information on CTF, case studies, workshops, and links to additional resources.

  2. Turning Traffic Jams to Jelly

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Beijing, known for having the worst traffic in China, is brewing up a traffic plan with the harshest ever measures to ensure smooth traffic flow as the capital’s gridlock during rush hour and private car sales soar.

  3. Zebrafish TRPA1 Channels Are Required for Chemosensation But Not for Thermosensation or Mechanosensory Hair Cell Function

    OpenAIRE

    Prober, David A.; Zimmerman, Steven; Myers, Benjamin R.; McDermott, Brian M.; Kim, Seok-Hyung; Caron, Sophie; Rihel, Jason; Solnica-Krezel, Lilianna; Julius, David; Hudspeth, A J; Schier, Alexander F.

    2008-01-01

    Transient receptor potential (TRP) ion channels have been implicated in detecting chemical, thermal, and mechanical stimuli in organisms ranging from mammals to Caenorhabditis elegans. It is well established that TRPA1 detects and mediates behavioral responses to chemical irritants. However, the role of TRPA1 in detecting thermal and mechanical stimuli is controversial. To further clarify the functions of TRPA1 channels in vertebrates, we analyzed their roles in zebrafish. The two zebrafish T...

  4. A knowledge-based system for controlling automobile traffic

    Science.gov (United States)

    Maravas, Alexander; Stengel, Robert F.

    1994-01-01

    Transportation network capacity variations arising from accidents, roadway maintenance activity, and special events as well as fluctuations in commuters' travel demands complicate traffic management. Artificial intelligence concepts and expert systems can be useful in framing policies for incident detection, congestion anticipation, and optimal traffic management. This paper examines the applicability of intelligent route guidance and control as decision aids for traffic management. Basic requirements for managing traffic are reviewed, concepts for studying traffic flow are introduced, and mathematical models for modeling traffic flow are examined. Measures for quantifying transportation network performance levels are chosen, and surveillance and control strategies are evaluated. It can be concluded that automated decision support holds great promise for aiding the efficient flow of automobile traffic over limited-access roadways, bridges, and tunnels.

  5. Bayesian analysis of traffic flow on interstate I-55: The LWR model

    OpenAIRE

    Polson, Nicholas; Sokolov, Vadim

    2014-01-01

    Transportation departments take actions to manage traffic flow and reduce travel times based on estimated current and projected traffic conditions. Travel time estimates and forecasts require information on traffic density which are combined with a model to project traffic flow such as the Lighthill–Whitham–Richards (LWR) model. We develop a particle filtering and learning algorithm to estimate the current traffic density state and the LWR parameters. These inputs are related to the so-called...

  6. Market driven network neutrality and the fallacies of Internet traffic quality regulation

    OpenAIRE

    Knieps, Günter

    2011-01-01

    In the U.S. paying for priority arrangements between Internet access service providers and Internet application providers to favor some traffic over other traf-fic is considered unreasonable discrimination. In Europe the focus is on mini-mum traffic quality requirements. It can be shown that neither market power nor universal service arguments can justify traffic quality regulation. In particular, heterogeneous demand for traffic quality for delay sensitive versus delay insen-sitive applicati...

  7. Agent Based Individual Traffic Guidance

    DEFF Research Database (Denmark)

    Wanscher, Jørgen

    This thesis investigates the possibilities in applying Operations Research (OR) to autonomous vehicular traffic. The explicit difference to most other research today is that we presume that an agent is present in every vehicle - hence Agent Based Individual Traffic guidance (ABIT). The next...... evolutionary step for the in-vehicle route planners is the introduction of two-way communication. We presume that the agent is capable of exactly this. Based on this presumption we discuss the possibilities and define a taxonomy and use this to discuss the ABIT system. Based on a set of scenarios we conclude...... that the system can be divided into two separate constituents. The immediate dispersion, which is used for small areas and quick response, and the individual alleviation, which considers the longer distance decision support. Both of these require intrinsicate models and cost functions which at the beginning...

  8. 44 CFR 15.14 - Vehicular and pedestrian traffic.

    Science.gov (United States)

    2010-10-01

    ... NATIONAL EMERGENCY TRAINING CENTER § 15.14 Vehicular and pedestrian traffic. (a) Drivers of all vehicles... signals and directions of the Police/Security Force or other authorized officials and all posted traffic signs; (b) Drivers must comply with NETC parking requirements and vehicle registration requirements;...

  9. Traffic Flow Wide-Area Surveillance system

    Energy Technology Data Exchange (ETDEWEB)

    Allgood, G.O.; Ferrell, R.K.; Kercel, S.W.; Abston, R.A.

    1994-09-01

    Traffic management can be thought of as a stochastic queuing process where the serving time at one of its control points is dynamically linked to the global traffic pattern, which is, in turn, dynamically linked to the control point. For this closed-loop system to be effective, the traffic management system must sense and interpret a large spatial projection of data originating from multiple sensor suites. This concept is the basis for the development of a Traffic Flow Wide-Area Surveillance (TFWAS) system. This paper presents the results of a study by Oak Ridge National Laboratory to define the operational specifications and characteristics, to determine the constraints, and to examine the state of technology of a TFWAS system in terms of traffic management and control. In doing so, the functions and attributes of a TFWAS system are mapped into an operational structure consistent with the Intelligent Vehicle Highway System (IVHS) concept and the existing highway infrastructure. This mapping includes identifying candidate sensor suites and establishing criteria, requirements, and performance measures by which these systems can be graded in their ability and practicality to meet the operational requirements of a TFWAS system. In light of this, issues such as system integration, applicable technologies, impact on traffic management and control, and public acceptance are addressed.

  10. VBR video traffic models

    CERN Document Server

    Tanwir, Savera

    2014-01-01

    There has been a phenomenal growth in video applications over the past few years. An accurate traffic model of Variable Bit Rate (VBR) video is necessary for performance evaluation of a network design and for generating synthetic traffic that can be used for benchmarking a network. A large number of models for VBR video traffic have been proposed in the literature for different types of video in the past 20 years. Here, the authors have classified and surveyed these models and have also evaluated the models for H.264 AVC and MVC encoded video and discussed their findings.

  11. Road Traffic Injuries

    Institute of Scientific and Technical Information of China (English)

    WANG Zheng-guo

    2005-01-01

    @@ As everybody knows that automobiles have been greatly changing our life. However, everything has two sides, motor vehicles have also caused a huge number of people's deaths, injuries and property damage. Traffic crashes are perhaps the number one public health problem in developed countries [1]. In the United States, pre-retirement years of life lost in traffic crashes are more than that of the two combined leading diseases: cancer and heart disease [1]. Today road traffic crash (RTC) ranks 11th in leading cause of death and accounts for 2.1% of all deaths globally.

  12. Requirement of Fra proteins for communication channels between cells in the filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120.

    Science.gov (United States)

    Omairi-Nasser, Amin; Mariscal, Vicente; Austin, Jotham R; Haselkorn, Robert

    2015-08-11

    The filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120 differentiates specialized cells, heterocysts, that fix atmospheric nitrogen and transfer the fixed nitrogen to adjacent vegetative cells. Reciprocally, vegetative cells transfer fixed carbon to heterocysts. Several routes have been described for metabolite exchange within the filament, one of which involves communicating channels that penetrate the septum between adjacent cells. Several fra gene mutants were isolated 25 y ago on the basis of their phenotypes: inability to fix nitrogen and fragmentation of filaments upon transfer from N+ to N- media. Cryopreservation combined with electron tomography were used to investigate the role of three fra gene products in channel formation. FraC and FraG are clearly involved in channel formation, whereas FraD has a minor part. Additionally, FraG was located close to the cytoplasmic membrane and in the heterocyst neck, using immunogold labeling with antibody raised to the N-terminal domain of the FraG protein.

  13. Energy-Efficient Relay Selection and Optimal Relay Location in Cooperative Cellular Networks with Asymmetric Traffic

    CERN Document Server

    Yang, Wei; Sun, Wanlu

    2010-01-01

    Energy-efficient communication is an important requirement for mobile relay networks due to the limited battery power of user terminals. This paper considers energy-efficient relaying schemes through selection of mobile relays in cooperative cellular systems with asymmetric traffic. The total energy consumption per information bit of the battery-powered terminals, i.e., the mobile station (MS) and the relay, is derived in theory. In the Joint Uplink and Downlink Relay Selection (JUDRS) scheme we proposed, the relay which minimizes the total energy consumption is selected. Additionally, the energy-efficient cooperation regions are investigated, and the optimal relay location is found for cooperative cellular systems with asymmetric traffic. The results reveal that the MS-relay and the relay-base station (BS) channels have different influence over relay selection decisions for optimal energy-efficiency. Information theoretic analysis of the diversity-multiplexing tradeoff (DMT) demonstrates that the proposed sc...

  14. Massively parallel processor networks with optical express channels

    Science.gov (United States)

    Deri, R.J.; Brooks, E.D. III; Haigh, R.E.; DeGroot, A.J.

    1999-08-24

    An optical method for separating and routing local and express channel data comprises interconnecting the nodes in a network with fiber optic cables. A single fiber optic cable carries both express channel traffic and local channel traffic, e.g., in a massively parallel processor (MPP) network. Express channel traffic is placed on, or filtered from, the fiber optic cable at a light frequency or a color different from that of the local channel traffic. The express channel traffic is thus placed on a light carrier that skips over the local intermediate nodes one-by-one by reflecting off of selective mirrors placed at each local node. The local-channel-traffic light carriers pass through the selective mirrors and are not reflected. A single fiber optic cable can thus be threaded throughout a three-dimensional matrix of nodes with the x,y,z directions of propagation encoded by the color of the respective light carriers for both local and express channel traffic. Thus frequency division multiple access is used to hierarchically separate the local and express channels to eliminate the bucket brigade latencies that would otherwise result if the express traffic had to hop between every local node to reach its ultimate destination. 3 figs.

  15. Two dimensional mixed traffic flow considering the transit traffic

    OpenAIRE

    Lingjiang Kong; Junhui Hu; Li Yang

    2012-01-01

    Based on the two-dimension cellular automaton traffic flow model (BML model), a mixed traffic flow model for urban traffic considering the transit traffic is established in this paper by using the Don't block the box rules. We have investigated the influences of the transit traffic ratio, and found that, in most cases, the urban traffic flow exhibited jam phase. Moreover, focusing on the traffic lights cycle, it is found that the average flow has the periodic fluctuation phenomenon, and we ha...

  16. Development and Evaluation of a Control System for Regional Traffic Management

    Directory of Open Access Journals (Sweden)

    John L. McLin

    2011-01-01

    Full Text Available Traffic congestion is a worsening problem in metropolitan areas which will require integrated regional traffic control systems to improve traffic conditions. This paper presents a regional traffic control system which can detect incident conditions and provide integrated traffic management during nonrecurrent congestion events. The system combines advanced artificial intelligence techniques with a traffic performance model based on HCM equations. Preliminary evaluation of the control system using traffic microsimulation demonstrates that it has the potential to improve system conditions during traffic incidents. In addition, several enhancements were identified which will make the system more robust in a real traffic control setting. An assessment of the control system elements indicates that there are no substantial technical barriers in implementing this system in a large traffic network.

  17. Dynamic random channel reservation protocol

    Institute of Scientific and Technical Information of China (English)

    Ren Yanying; Zhang Wenjun; Yu Songyu

    2005-01-01

    Demand assignment MAC protocols have been used widely in wireless networks. It can effectively utilize wireless bandwidth. Some strategies can be used by demand assignment MAC protocols to further improve their efficiency. The concept of transmit probability is introduced. This concept allows a request slot to be assigned to many different traffic classes at the same time. Based on it, the dynamic random channel reservation (DRCR) protocol is proposed. The DRCR protocol operates dynamically by observing the traffic conditions. It uses information about the recent traffic conditions to assign transmit probability with which an mobile station can select request slots with lower traffic. The performance of DRCR is evaluated and compared with RSCA. The results show that DRCR is more stable than RSCA, it offers shorter delays of requests than RSCA and can relieve heavily stressed traffic classes faster than RSCA.

  18. Non-Traffic Citations

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Non-traffic citations (NTCs, also known as "summary offenses") document low-level criminal offenses where a law enforcement officer or other authorized official...

  19. Dementia and Traffic Accidents

    DEFF Research Database (Denmark)

    Petersen, Jindong Ding; Siersma, Volkert; Nielsen, Connie Thurøe;

    2016-01-01

    BACKGROUND: As a consequence of a rapid growth of an ageing population, more people with dementia are expected on the roads. Little is known about whether these people are at increased risk of road traffic-related accidents. OBJECTIVE: Our study aims to investigate the risk of road traffic...... Central Research Register, and/or (2) at least one dementia diagnosis-related drug prescription registration in the Danish National Prescription Registry. Police-, hospital-, and emergency room-reported road traffic-related accidents occurred within the study follow-up are defined as the study outcome...... selection bias due to nonparticipation and loss to follow-up. Furthermore, this ensures that the study results are reliable and generalizable. However, underreporting of traffic-related accidents may occur, which will limit estimation of absolute risks....

  20. Accurate Multisteps Traffic Flow Prediction Based on SVM

    OpenAIRE

    Zhang Mingheng; Zhen Yaobao; Hui Ganglong; Chen Gang

    2013-01-01

    Accurate traffic flow prediction is prerequisite and important for realizing intelligent traffic control and guidance, and it is also the objective requirement for intelligent traffic management. Due to the strong nonlinear, stochastic, time-varying characteristics of urban transport system, artificial intelligence methods such as support vector machine (SVM) are now receiving more and more attentions in this research field. Compared with the traditional single-step prediction method, the mul...

  1. Turning Traffic Jams to Jelly

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ Beijing, known for having the worst traffic in China, is brewing up a traffic plan with the harshest ever measures to ensure smooth traffic flow as the capital's gridlock during rush hour and private car sales soar. On December 13, the Beijing Municipal Government started soliciting public opinions for a draft plan designed to relieve the city's traffic problems.

  2. Traffic-Adaptive Routing

    OpenAIRE

    Kammenhuber, Nils

    2011-01-01

    Despite the bursty and highly volatile traffic, routing in the Internet today is optimised only on coarse time scales, as load-adaptive routing is known to induce performance deterioration by causing massive oscillations. We describe ReplEx, an universally applicable distributed algorithm for dynamic routing/traffic engineering, which is based on game theory. We show through extensive realistic simulations that ReplEx does not oscillate, and that it achieves performance gains comparable to tr...

  3. Traffic engineering eye diagram

    OpenAIRE

    Kowalik, Karol; Collier, Martin

    2005-01-01

    It is said that a picture is worth a thousand words - this statement also applies to networking topics. Thus, to effectively monitor network performance we need tools which present the performance metrics in a graphical way which is also clear and informative. We propose a tool for this purpose which we call the traffic engineering eye diagram (TEED). Eye diagrams are used in digital communications to analyse the quality of a digital signal; the TEED can similarly he used in the traffic engin...

  4. Penalties in traffic.

    OpenAIRE

    2009-01-01

    Traffic offenders are penalized in various ways: fines, (temporary) driving licence suspensions, confiscation of their vehicles, penalty points, mandatory participation in rehabilitation programmes, prison sentences or community service. The aim of penalties is to punish offenders, to protect society and to influence the behaviour of offenders and all citizens (prevention). Many studies have found that the combination of enforcement and penalties prevent the violation of traffic regulations a...

  5. RESEARCH OF ENGINEERING TRAFFIC IN COMPUTER UZ NETWORK USING MPLS TE TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    V. M. Pakhomovа

    2014-12-01

    Full Text Available Purpose. In railway transport of Ukraine one requires the use of computer networks of different technologies: Ethernet, Token Bus, Token Ring, FDDI and others. In combined computer networks on the railway transport it is necessary to use packet switching technology in multiprotocol networks MPLS (MultiProtocol Label Switching more effectively. They are based on the use of tags. Packet network must transmit different types of traffic with a given quality of service. The purpose of the research is development a methodology for determining the sequence of destination flows for the considered fragment of computer network of UZ. Methodology. When optimizing traffic management in MPLS networks has the important role of technology traffic engineering (Traffic Engineering, TE. The main mechanism of TE in MPLS is the use of unidirectional tunnels (MPLS TE tunnel to specify the path of the specified traffic. The mathematical model of the problem of traffic engineering in computer network of UZ technology MPLS TE was made. Computer UZ network is represented with the directed graph, their vertices are routers of computer network, and each arc simulates communication between nodes. As an optimization criterion serves the minimum value of the maximum utilization of the TE-tunnel. Findings. The six options destination flows were determined; rational sequence of flows was found, at which the maximum utilization of TE-tunnels considered a simplified fragment of a computer UZ network does not exceed 0.5. Originality. The method of solving the problem of traffic engineering in Multiprotocol network UZ technology MPLS TE was proposed; for different classes its own way is laid, depending on the bandwidth and channel loading. Practical value. Ability to determine the values of the maximum coefficient of use of TE-tunnels in computer UZ networks based on developed software model «TraffEng». The input parameters of the model: number of routers, channel capacity, the

  6. Dystrophin is required for the normal function of the cardio-protective K(ATP channel in cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Laura Graciotti

    Full Text Available Duchenne and Becker muscular dystrophy patients often develop a cardiomyopathy for which the pathogenesis is still unknown. We have employed the murine animal model of Duchenne muscular dystrophy (mdx, which develops a cardiomyopathy that includes some characteristics of the human disease, to study the molecular basis of this pathology. Here we show that the mdx mouse heart has defects consistent with alteration in compounds that regulate energy homeostasis including a marked decrease in creatine-phosphate (PC. In addition, the mdx heart is more susceptible to anoxia than controls. Since the cardio-protective ATP sensitive potassium channel (K(ATP complex and PC have been shown to interact we investigated whether deficits in PC levels correlate with other molecular events including K(ATP ion channel complex presence, its functionality and interaction with dystrophin. We found that this channel complex is present in the dystrophic cardiac cell membrane but its ability to sense a drop in the intracellular ATP concentration and consequently open is compromised by the absence of dystrophin. We further demonstrate that the creatine kinase muscle isoform (CKm is displaced from the plasma membrane of the mdx cardiac cells. Considering that CKm is a determinant of K(ATP channel complex function we hypothesize that dystrophin acts as a scaffolding protein organizing the K(ATP channel complex and the enzymes necessary for its correct functioning. Therefore, the lack of proper functioning of the cardio-protective K(ATP system in the mdx cardiomyocytes may be part of the mechanism contributing to development of cardiac disease in dystrophic patients.

  7. Ant traffic rules.

    Science.gov (United States)

    Fourcassié, Vincent; Dussutour, Audrey; Deneubourg, Jean-Louis

    2010-07-15

    Many animals take part in flow-like collective movements. In most species, however, the flow is unidirectional. Ants are one of the rare group of organisms in which flow-like movements are predominantly bidirectional. This adds to the difficulty of the task of maintaining a smooth, efficient movement. Yet, ants seem to fare well at this task. Do they really? And if so, how do such simple organisms succeed in maintaining a smooth traffic flow, when even humans experience trouble with this task? How does traffic in ants compare with that in human pedestrians or vehicles? The experimental study of ant traffic is only a few years old but it has already provided interesting insights into traffic organization and regulation in animals, showing in particular that an ant colony as a whole can be considered as a typical self-organized adaptive system. In this review we will show that the study of ant traffic can not only uncover basic principles of behavioral ecology and evolution in social insects but also provide new insights into the study of traffic systems in general. PMID:20581264

  8. Urban planning and traffic safety at night

    Science.gov (United States)

    Ispas, N.; Trusca, D.

    2016-08-01

    Urban planning including traffic signs serve vital functions, providing road users with regulatory, warning and guidance information about the roadway and surrounding environment. There are a large number of signs and even more guidelines on how these signs should be designed, installed, and maintained in concordance with on road surface traffic signs. More requirements for signs are made for night urban traffic, including appearance (size, shape, colour), placement (height, lateral, and longitudinal), maintenance (visibility, position, damage) and signs light and retroreflective. In the night, traffic signs visibility can interact by on pedestrian visibility and diminish urban traffic safety. The main aim of this paper are the scientific determination of an urban specific zone visibility for evaluate at night real conditions in case of a traffic accident in the Braşov city area. The night visibility study was made using PC-Rect version 4.2. Other goal of the paper was to modify some urban planning solution in order to increase the urban safety in Brașov.

  9. Traffic Monitoring and Control Using RFID

    Directory of Open Access Journals (Sweden)

    Gaurav Thakur

    2013-09-01

    Full Text Available Traffic congestion and tidal flow management were recognized as major problems in modern urban areas, which have caused much frustration and loss of man hours. The operation of standard traffic lights which are currently deployed in many junctions, are based on predetermined timing schemes, which are fixed during the installation and remain until further resetting. The timing is no more than a default setup to control what may be considered as normal traffic. Although every road junction by necessity requires different traffic light timing setup, many existing systems operate with a default sequence. To design an intelligent and efficient traffic control system, a number of parameters that represent the status of the road conditions must be identified and taken into consideration. Approach: In order to solve the problem an intelligent RFID traffic control has been developed. This project is based on monitoring the traffic density at the signal using RFID Reader. RFID tags which is placed (instead of number plate at each vehicle will serve as the unique number of vehicle .Reader will count the number of tags at the signal and take decision of increasing or decreasing the signal time .This reader is also use to find the violation(VIN of violator of the signal. Each passive tag will have certain number of bytes information will be different for different vehicles. Whenever any tag will approach any signal, reader will take that bytes of information and simultaneously will also increment the number of vehicles for making decision to change the signal timing. Each tag of data will be stored in main memory (database.This unique data will also help in determining the violator of the signal .Thus it will save human efforts and resources to a greater extent and reduce waiting of the people at the signal. After implementation of this project, now all people waiting at the signal will get proper time (green light according to the traffic density

  10. Traffic Information System for Hanoi

    OpenAIRE

    Sohr, Alexander; Brockfeld, Elmar; Sauerländer-Biebl, Anke; Melde, Eric

    2016-01-01

    To improve the traffic situation in Hanoi it is necessary to have a good overview of the existing traffic situation and to monitor the development of the traffic over longer time periods. Floating Car Data (FCD) Systems can help to acquire area wide traffic information; here a FCD system based on taxis, busses and motor-cycles is described. It consists of Web and App tools and a Hotspot-Monitoring for long term traffic analysis.

  11. Traffic management as a service: the traffic flow pattern classification problem

    OpenAIRE

    Carlos T. Calafate; David Soler; Juan-Carlos Cano; Pietro Manzoni

    2015-01-01

    Intelligent Transportation System (ITS) technologies can be implemented to reduce both fuel consumption and the associated emission of greenhouse gases. However, such systems require intelligent and effective route planning solutions to reduce travel time and promote stable traveling speeds. To achieve such goal these systems should account for both estimated and real-time traffic congestion states, but obtaining reliable traffic congestion estimations for all the streets/avenues in a city...

  12. AN MAC PROTOCOL SUPPORTING MULTIPLE TRAFFIC OVER MOBILE AD HOC NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Tian Hui; Li Yingyang; Hu Jiandong; Zhang Ping

    2003-01-01

    This letter presents the design and performance of a multi-channel MAC protocol that supports multiple traffics for IEEE 802.11 mobile ad-hoc networks. The dynamic channel selection scheme by receiver decision is implemented and the number of the data channel is independent of the network topology. The priority for real-time traffic is assured by the proposed adaptive back off algorithm and different IFS. The protocol is evaluated by simulation and the results have shown that it can support multiple traffics and the performance is better than the performance that IEEE 802.11 standard provides.

  13. AN MAC PROTOCOL SUPPORTING MULTIPLE TRAFFIC OVER MOBILE AD HOC NETWORKS

    Institute of Scientific and Technical Information of China (English)

    TianHui; LiYingyang

    2003-01-01

    This letter presents the design and performance of a multi-channel MAC protocol that supports multiple traffics for IEEE 802.11 mobile ad-hoc networks.The dynamic channel selection scheme by receiver decision is implemented and the number of the data channel is independent of the network topology.The priority for real-time traffic is assured by the proposed adaptive back off algorithm and different IFS.The protocol is evaluated by simulation and the results have shown that it can support multiple traffics and the performance is better than the performance that IEEE 802.11 standard provides.

  14. Molecular Motors and Apical CFTR Traffic in Epithelia

    Directory of Open Access Journals (Sweden)

    Dmitri V. Kravtsov

    2013-05-01

    Full Text Available Intracellular protein traffic plays an important role in the regulation of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR chloride channels. Microtubule and actin-based motor proteins direct CFTR movement along trafficking pathways. As shown for other regulatory proteins such as adaptors, the involvement of protein motors in CFTR traffic is cell-type specific. Understanding motor specificity provides insight into the biology of the channel and opens opportunity for discovery of organ-specific drug targets for treating CFTR-mediated diseases.

  15. Efficient particle-based estimation of marginal costs in a first-order macroscopic traffic flow model

    NARCIS (Netherlands)

    Zuurbier, F.S.; Hegyi, A.; Hoogendoorn, S.P.

    2010-01-01

    Marginal costs in traffic networks are the extra costs incurred to the system as the result of extra traffic. Marginal costs are required frequently e.g. when considering system optimal traffic assignment or tolling problems. When explicitly considering spillback in a traffic flow model, one can use

  16. Traffic danger detection by visual attention model of sparse sampling

    Institute of Scientific and Technical Information of China (English)

    夏利民; 刘涛; 谭论正

    2015-01-01

    A method to detect traffic dangers based on visual attention model of sparse sampling was proposed. The hemispherical sparse sampling model was used to decrease the amount of calculation which increases the detection speed. Bayesian probability model and Gaussian kernel function were applied to calculate the saliency of traffic videos. The method of multiscale saliency was used and the final saliency was the average of all scales, which increased the detection rates extraordinarily. The detection results of several typical traffic dangers show that the proposed method has higher detection rates and speed, which meets the requirement of real-time detection of traffic dangers.

  17. A New Cellular Automaton Model for Traffic Flow

    Institute of Scientific and Technical Information of China (English)

    YongtaoHU

    1999-01-01

    Establishment of effective traffic models to reveal fundamental traffic characteristics is an essential requirement in the design,planning and operation of transportation systems .In 1992 Nagel and Schreckenberg presented a cellular automaton model describing traffic flow of N cars on a single lane and applied it in the famous project TRANSIMS on transportation simulation.In this paper,the author proposes a new model for the same problem and gives a comparison of simulation results with the former ones.The comparison shows that the new model works better under the condition of high traffic density.

  18. 14 CFR 298.61 - Reporting of traffic statistics.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Reporting of traffic statistics. 298.61... Requirements § 298.61 Reporting of traffic statistics. (a) Each commuter air carrier and small certificated air... statistics shall be compiled in terms of each flight stage as actually performed. The detail T-100 data...

  19. Road lighting and traffic safety : a functional approach.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1970-01-01

    Requirements to be made on the traffic facilities in order to reduce the number of night-time accidents are covered. Traffic facilities include apart from public lighting and road lighting by means of headlamps of vehicles, also road markings and signs, marker lights, catadioptric devices and others

  20. Hydrogen sulfide-induced itch requires activation of Cav3.2 T-type calcium channel in mice

    Science.gov (United States)

    Wang, Xue-Long; Tian, Bin; Huang, Ya; Peng, Xiao-Yan; Chen, Li-Hua; Li, Jun-Cheng; Liu, Tong

    2015-01-01

    The contributions of gasotransmitters to itch sensation are largely unknown. In this study, we aimed to investigate the roles of hydrogen sulfide (H2S), a ubiquitous gasotransmitter, in itch signaling. We found that intradermal injection of H2S donors NaHS or Na2S, but not GYY4137 (a slow-releasing H2S donor), dose-dependently induced scratching behavior in a μ-opioid receptor-dependent and histamine-independent manner in mice. Interestingly, NaHS induced itch via unique mechanisms that involved capsaicin-insensitive A-fibers, but not TRPV1-expressing C-fibers that are traditionally considered for mediating itch, revealed by depletion of TRPV1-expressing C-fibers by systemic resiniferatoxin treatment. Moreover, local application of capsaizapine (TRPV1 blocker) or HC-030031 (TRPA1 blocker) had no effects on NaHS-evoked scratching. Strikingly, pharmacological blockade and silencing of Cav3.2 T-type calcium channel by mibefradil, ascorbic acid, zinc chloride or Cav3.2 siRNA dramatically decreased NaHS-evoked scratching. NaHS induced robust alloknesis (touch-evoked itch), which was inhibited by T-type calcium channels blocker mibefradil. Compound 48/80-induced itch was enhanced by an endogenous precursor of H2S (L-cysteine) but attenuated by inhibitors of H2S-producing enzymes cystathionine γ-lyase and cystathionine β-synthase. These results indicated that H2S, as a novel nonhistaminergic itch mediator, may activates Cav3.2 T-type calcium channel, probably located at A-fibers, to induce scratching and alloknesis in mice. PMID:26602811

  1. Emergent traffic jams

    CERN Document Server

    Nagel, K; Nagel, Kai; Paczuski, Maya

    1995-01-01

    We study a single-lane traffic model that is based on human driving behavior. The outflow from a traffic jam self-organizes to a critical state of maximum throughput. Small perturbations of the outflow far downstream create emergent traffic jams with a power law distribution P(t) \\sim t^{-3/2} of lifetimes, t. On varying the vehicle density in a closed system, this critical state separates lamellar and jammed regimes, and exhibits 1/f noise in the power spectrum. Using random walk arguments, in conjunction with a cascade equation, we develop a phenomenological theory that predicts the critical exponents for this transition and explains the self-organizing behavior. These predictions are consistent with all of our numerical results.

  2. Inaccuracy in traffic forecasts

    DEFF Research Database (Denmark)

    Flyvbjerg, Bent; Holm, Mette K. Skamris; Buhl, Søren Ladegaard

    2006-01-01

    This paper presents results from the first statistically significant study of traffic forecasts in transportation infrastructure projects. The sample used is the largest of its kind, covering 210 projects in 14 nations worth US$58 billion. The study shows with very high statistical significance......, the difference between actual and forecasted traffic is more than +-20%; for 25% of road projects, the difference is larger than +-40%. Forecasts for roads are more accurate and more balanced than for rail, with no significant difference between the frequency of inflated versus deflated forecasts. But for both...... forecasting. Highly inaccurate traffic forecasts combined with large standard deviations translate into large financial and economic risks. But such risks are typically ignored or downplayed by planners and decision-makers, to the detriment of social and economic welfare. The paper presents the data...

  3. Traffic Engineering in Metro Ethernet

    Directory of Open Access Journals (Sweden)

    Padmaraj Nair

    2010-05-01

    Full Text Available Traffic engineering is one of the major issues that has to be addressed in Metro Ethernet networks for quality of service and efficient resource utilization. This paper aims at understanding the relevant issues and outlines novel algorithms for multipoint traffic engineering in Metro Ethernet. We present an algorithmic solution for traffic engineering in Metro Ethernet using optimal multiple spanning trees. This iterative approach distributes traffic across the network uniformly without overloading network resources. We also introduce a new traffic specification model for Metro Ethernet, which is a hybrid of two widely used traffic specification models, the pipe and hose models.

  4. An analytical model of pipelined circuit switching in hypercubes in the presence of hot spot traffic

    OpenAIRE

    Safaei, F.; Khonsari, A.; Fathy, M.; Ould-Khaoua, M.

    2005-01-01

    Several recent studies have revealed that PCS can provide superior performance characteristics over wormhole switching under uniform traffic. Analytical model of PCS for common networks (e.g., hypercube) under uniform traffic pattern have recently been reported in the literature. In this paper we propose an analytical model of PCS in the hypercube network augmented with virtual channel in the presence of hot spot traffic. The model has a good agreement with simulation experiments.

  5. Generalized Deterministic Traffic Rules

    CERN Document Server

    Fuks, H; Fuks, Henryk; Boccara, Nino

    1997-01-01

    We study a family of deterministic models for highway traffic flow which generalize cellular automaton rule 184. This family is parametrized by the speed limit $m$ and another parameter $k$ that represents a ``degree of aggressiveness'' in driving, strictly related to the distance between two consecutive cars. We compare two driving strategies with identical maximum throughput: ``conservative'' driving with high speed limit and ``aggressive'' driving with low speed limit. Those two strategies are evaluated in terms of accident probability. We also discuss fundamental diagrams of generalized traffic rules and examine limitations of maximum achievable throughput. Possible modifications of the model are considered.

  6. An online railway traffic prediction model

    NARCIS (Netherlands)

    Kecman, P.; Goverde, R.M.P.

    2013-01-01

    Prediction of train positions in time and space is required for traffic control and passenger information. However, in practice only the last measured train delays are known and dispatchers must predict the arrival times of trains without adequate computer support. This paper presents a real-time to

  7. The Earliest Ion Channels

    Science.gov (United States)

    Pohorille, A.; Wilson, M. A.; Wei, C.

    2009-12-01

    Supplying protocells with ions required assistance from channels spanning their membrane walls. The earliest channels were most likely short proteins that formed transmembrane helical bundles surrounding a water-filled pore. These simple aggregates were capable of transporting ions with efficiencies comparable to those of complex, contemporary ion channels. Channels with wide pores exhibited little ion selectivity but also imposed only modest constraints on amino acid sequences of channel-forming proteins. Channels with small pores could have been selective but also might have required a more precisely defined sequence of amino acids. In contrast to modern channels, their protocellular ancestors had only limited capabilities to regulate ion flux. It is postulated that subsequent evolution of ion channels progressed primarily to acquire precise regulation, and not high efficiency or selectivity. It is further proposed that channels and the surrounding membranes co-evolved.

  8. Traffic Management as a Service: The Traffic Flow Pattern Classification Problem

    Directory of Open Access Journals (Sweden)

    Carlos T. Calafate

    2015-01-01

    Full Text Available Intelligent Transportation System (ITS technologies can be implemented to reduce both fuel consumption and the associated emission of greenhouse gases. However, such systems require intelligent and effective route planning solutions to reduce travel time and promote stable traveling speeds. To achieve such goal these systems should account for both estimated and real-time traffic congestion states, but obtaining reliable traffic congestion estimations for all the streets/avenues in a city for the different times of the day, for every day in a year, is a complex task. Modeling such a tremendous amount of data can be time-consuming and, additionally, centralized computation of optimal routes based on such time-dependencies has very high data processing requirements. In this paper we approach this problem through a heuristic to considerably reduce the modeling effort while maintaining the benefits of time-dependent traffic congestion modeling. In particular, we propose grouping streets by taking into account real traces describing the daily traffic pattern. The effectiveness of this heuristic is assessed for the city of Valencia, Spain, and the results obtained show that it is possible to reduce the required number of daily traffic flow patterns by a factor of 4210 while maintaining the essence of time-dependent modeling requirements.

  9. Aberrantly Over-Expressed TRPM8 Channels in Pancreatic Adenocarcinoma: Correlation with Tumor Size/Stage and Requirement for Cancer Cells Invasion

    Directory of Open Access Journals (Sweden)

    Nelson S. Yee

    2014-05-01

    Full Text Available The transient receptor potential melastatin-subfamily member 8 (TRPM8 channels control Ca2+ homeostasis. Recent studies indicate that TRPM8 channels are aberrantly expressed and required for cellular proliferation in pancreatic adenocarcinoma. However, the functional significance of TRPM8 in pancreatic tissues is mostly unknown. The objectives of this study are to examine the expression of TRPM8 in various histopathological types of pancreatic tissues, determine its clinical significance in pancreatic adenocarcinoma, and investigate its functional role in cancer cells invasion. We present evidence that, in normal pancreatic tissues, anti-TRPM8 immunoreactivity is detected in the centroacinar cells and the islet endocrine cells. In pre-malignant pancreatic tissues and malignant neoplasms, TRPM8 is aberrantly expressed to variable extents. In the majority of pancreatic adenocarcinoma, TRPM8 is expressed at moderate or high levels, and anti-TRPM8 immunoreactivity positively correlates with the primary tumor size and stage. In the pancreatic adenocarcinoma cell lines that express relatively high levels of TRPM8, short hairpin RNA-mediated interference of TRPM8 expression impaired their ability of invasion. These data suggest that aberrantly expressed TRPM8 channels play contributory roles in pancreatic tumor growth and metastasis, and support exploration of TRPM8 as a biomarker and target of pancreatic adenocarcinoma.

  10. Identification of Amino Acid Residues in Fibroblast Growth Factor 14 (FGF14) Required for Structure-Function Interactions with Voltage-gated Sodium Channel Nav1.6.

    Science.gov (United States)

    Ali, Syed R; Singh, Aditya K; Laezza, Fernanda

    2016-05-20

    The voltage-gated Na(+) (Nav) channel provides the basis for electrical excitability in the brain. This channel is regulated by a number of accessory proteins including fibroblast growth factor 14 (FGF14), a member of the intracellular FGF family. In addition to forming homodimers, FGF14 binds directly to the Nav1.6 channel C-tail, regulating channel gating and expression, properties that are required for intrinsic excitability in neurons. Seeking amino acid residues with unique roles at the protein-protein interaction interface (PPI) of FGF14·Nav1.6, we engineered model-guided mutations of FGF14 and validated their impact on the FGF14·Nav1.6 complex and the FGF14:FGF14 dimer formation using a luciferase assay. Divergence was found in the β-9 sheet of FGF14 where an alanine (Ala) mutation of Val-160 impaired binding to Nav1.6 but had no effect on FGF14:FGF14 dimer formation. Additional analysis revealed also a key role of residues Lys-74/Ile-76 at the N-terminal of FGF14 in the FGF14·Nav1.6 complex and FGF14:FGF14 dimer formation. Using whole-cell patch clamp electrophysiology, we demonstrated that either the FGF14(V160A) or the FGF14(K74A/I76A) mutation was sufficient to abolish the FGF14-dependent regulation of peak transient Na(+) currents and the voltage-dependent activation and steady-state inactivation of Nav1.6; but only V160A with a concomitant alanine mutation at Tyr-158 could impede FGF14-dependent modulation of the channel fast inactivation. Intrinsic fluorescence spectroscopy of purified proteins confirmed a stronger binding reduction of FGF14(V160A) to the Nav1.6 C-tail compared with FGF14(K74A/I76A) Altogether these studies indicate that the β-9 sheet and the N terminus of FGF14 are well positioned targets for drug development of PPI-based allosteric modulators of Nav channels. PMID:26994141

  11. Distributed learning and multi-objectivity in traffic light control

    Science.gov (United States)

    Brys, Tim; Pham, Tong T.; Taylor, Matthew E.

    2014-01-01

    Traffic jams and suboptimal traffic flows are ubiquitous in modern societies, and they create enormous economic losses each year. Delays at traffic lights alone account for roughly 10% of all delays in US traffic. As most traffic light scheduling systems currently in use are static, set up by human experts rather than being adaptive, the interest in machine learning approaches to this problem has increased in recent years. Reinforcement learning (RL) approaches are often used in these studies, as they require little pre-existing knowledge about traffic flows. Distributed constraint optimisation approaches (DCOP) have also been shown to be successful, but are limited to cases where the traffic flows are known. The distributed coordination of exploration and exploitation (DCEE) framework was recently proposed to introduce learning in the DCOP framework. In this paper, we present a study of DCEE and RL techniques in a complex simulator, illustrating the particular advantages of each, comparing them against standard isolated traffic actuated signals. We analyse how learning and coordination behave under different traffic conditions, and discuss the multi-objective nature of the problem. Finally we evaluate several alternative reward signals in the best performing approach, some of these taking advantage of the correlation between the problem-inherent objectives to improve performance.

  12. Surface Traffic Management Research

    Science.gov (United States)

    Jung, Yoo Chul

    2012-01-01

    This presentation discusses an overview of the surface traffic management research conducted by NASA Ames. The concept and human-in-the-loop simulation of the Spot and Runway Departure Advisor (SARDA), an integrated decision support tool for the tower controllers and airline ramp operators, is also discussed.

  13. Air Traffic Flow Management

    CERN Document Server

    Ganu, Hrishikesh V

    2008-01-01

    Air Traffic Flow Management is the regulation of air traffic in order to avoid exceeding airport or flight sector capacity in handling traffic, and to ensure that available capacity is used efficiently. We have tried to explore the logic behind the claims by Bertsimas et.al about integral solutions to the LP relaxation of the Traffic Flow Management Problem(TFMP). Polyhedral theory only indicates that the stronger TFMP formulation of Bertsimas et.al might lead to integral solutions in some cases. Our computations indicate that the encouraging results reported by Bertsimas et.al are not merely fortuitous or due to their specific data set. Indeed, we found that the TFMP had integral solutions even in case of artificial data sets generated to include severe conflicts in the flight schedules. In our limited tests with 4-5 scenarios, we obtained non-integral solutions only once. This is of significant practical importance because, the LP relaxation can be solved even on small machines with low memory and processor...

  14. Occupant traffic estimation through structural vibration sensing

    Science.gov (United States)

    Pan, Shijia; Mirshekari, Mostafa; Zhang, Pei; Noh, Hae Young

    2016-04-01

    The number of people passing through different indoor areas is useful in various smart structure applications, including occupancy-based building energy/space management, marketing research, security, etc. Existing approaches to estimate occupant traffic include vision-, sound-, and radio-based (mobile) sensing methods, which have placement limitations (e.g., requirement of line-of-sight, quiet environment, carrying a device all the time). Such limitations make these direct sensing approaches difficult to deploy and maintain. An indirect approach using geophones to measure floor vibration induced by footsteps can be utilized. However, the main challenge lies in distinguishing multiple simultaneous walkers by developing features that can effectively represent the number of mixed signals and characterize the selected features under different traffic conditions. This paper presents a method to monitor multiple persons. Once the vibration signals are obtained, features are extracted to describe the overlapping vibration signals induced by multiple footsteps, which are used for occupancy traffic estimation. In particular, we focus on analysis of the efficiency and limitations of the four selected key features when used for estimating various traffic conditions. We characterize these features with signals collected from controlled impulse load tests as well as from multiple people walking through a real-world sensing area. In our experiments, the system achieves the mean estimation error of +/-0.2 people for different occupant traffic conditions (from one to four) using k-nearest neighbor classifier.

  15. Traffic Management for Next Generation Transport Networks

    DEFF Research Database (Denmark)

    Yu, Hao

    management functions at the edge of the network, scheduling traffic on behalf of the other nodes. The topology-based hierarchical scheduling scheme is able to provide outstanding flow isolation due to its centralized scheduling ability, which is essential for providing IPTV services. In order to reduce...... their network capacities. However, in order to provide more advanced video services than simply porting the traditional television services to the network, the service provider needs to do more than just augment the network capacity. Advanced traffic management capability is one of the relevant abilities...... the required bandwidth, multicast is favored for providing IPTV services. Currently, transport networks lack sufficient multicast abilities. With the increase of the network capacity, it is challenging to build a multicast-enabled switch for the transport network, because, from the traffic management’s...

  16. Traffic Engineering in Metro Ethernet

    OpenAIRE

    Padmaraj Nair; Suku Nair; Girish Chiruvolu

    2010-01-01

    Traffic engineering is one of the major issues that has to be addressed in Metro Ethernet networks for quality of service and efficient resource utilization. This paper aims at understanding the relevant issues and outlines novel algorithms for multipoint traffic engineering in Metro Ethernet. We present an algorithmic solution for traffic engineering in Metro Ethernet using optimal multiple spanning trees. This iterative approach distributes traffic across the network uniformly without overl...

  17. Chaotic Control of Network Traffic

    Institute of Scientific and Technical Information of China (English)

    YANG Tan; CUI Yi-Dong; JIN Yue-Hui; CHENG Shi-Duan

    2009-01-01

    A method of chaotic control on network traffic is presented.By this method,the chaotic network traffic can be controlled to a pre-assigned equilibrium point according to chaotic prediction and the largest Lyapunov exponent of the traffic on congested link is reduced,thereby the probability of traffic burst and network congestion can be reduced.Numerical examples show that this method is effective.

  18. Road Traffic Accidents in Kazakhstan

    OpenAIRE

    Alma Aubakirova; Alibek Kossumov; Nurbek Igissinov

    2013-01-01

    Background: The article provides the analysis of death rates in road traffic accidents in Kazakhstan from 2004 to 2010 and explores the use of sanitary aviation. Methods: Data of fatalities caused by road traffic accidents were collected and analysed. Descriptive and analytical methods of epidemiology and biomedical statistics were applied. Results: Totaly 27,003 people died as a result of road traffic accidents in this period. The death rate for the total population due to road traffic accid...

  19. Traffic flow modeling: a Genealogy

    OpenAIRE

    Van Wageningen-Kessels, F.L.M.; Hoogendoorn, S.P.; Vuik, C.; Lint, van J. W. C.

    2014-01-01

    80 years ago, Bruce Greenshields presented the first traffic flow model at the Annual Meeting of the Highway Research Board. Since then, many models and simulation tools have been developed. We show a model tree with four families of traffic flow models, all descending from Greenshields' model. The tree shows the historical development of traffic flow modeling and the relations between models. Based on the tree we discuss the main trends and future developments in traffic flow modeling and si...

  20. Traffic sign detection and analysis

    DEFF Research Database (Denmark)

    Møgelmose, Andreas; Trivedi, Mohan M.; Moeslund, Thomas B.

    2012-01-01

    Traffic sign recognition (TSR) is a research field that has seen much activity in the recent decade. This paper introduces the problem and presents 4 recent papers on traffic sign detection and 4 recent papers on traffic sign classification. It attempts to extract recent trends in the field...

  1. Impact of traffic noise on railway traffic safety

    Directory of Open Access Journals (Sweden)

    Zdravko TOŠ

    2008-01-01

    Full Text Available Traffic noise is one of the dominant factors of ergo-assessment. The harmful impact of traffic noise on the engine driver as target group can be studied in isolation from other ergo-assessment factors only in the initial phase of research. The simultaneous action of several related factors in the system of ergo-assessment factors has cumulative effect on the perception and psychomotoric status of the railway traffic participants in the appropriate traffic situation. The initial partial research of traffic noise by a combination of several scientific methods needs to be eventually upgraded by studying the relations among several concurrent important or dominant ergo-assessment factors.

  2. Policy Refinement for Traffic Management in Home Area Networks: Problem Statement

    OpenAIRE

    Rana, Annie Ibrahim; O Foghlu, Micheal

    2009-01-01

    Traditional home area network (HAN) equipment is usually unmanaged and network traffic is served in best effort fashion. This type of unmanaged network sometimes causes quality-of-service issues in the HAN, for example loss of quality in streamed video or audio content. Traffic management rules using policies to prioritise certain types of traffic according to user requirements and to assign bandwidth limits to other traffic types. However very little work has been done yet addressing the ...

  3. COLOMBO: Exploiting Vehicular Communications at Low Equipment Rates for Traffic Management Purposes

    OpenAIRE

    Krajzewicz, Daniel; Leich, Andreas; Blokpoel, Robbin; Milano, Michela; Stützle, Thomas

    2015-01-01

    While most standardized vehicular communication applications aim on increasing traffic safety, the exchange of messages between vehicles and the environment may be well used for other purposes at no additional cost as well. One possible area of applications is traffic management. Traffic management requires data about the state of the road network. Before being able to predict or control traffic, according data is needed. The COLOMBO project, co-funded by the European Commission, examines the...

  4. Survivable Impairment-aware Traffic Grooming in WDM Rings

    NARCIS (Netherlands)

    Beshir, A.; Fernando Kuipers, F.; Orda, A.; Van Mieghem, P.

    Wavelength Division Multiplexing (WDM) optical networks offer a large amount of bandwidth using multiple, but independent wavelength channels (or lightpaths), each operating at several Gb/s. Since the traffic between users is usually only a fraction of the capacity offered by a wavelength, several i

  5. Effects of Traffic Lights on CA Traffic Model

    Institute of Scientific and Technical Information of China (English)

    SuweiFENG; GuoqingGU

    1997-01-01

    Cellular automaton traffic models can include various factors in traffic system with simple regulations and the corresponding computations and simulations are rather convenient and effective.In this paper,the Biham-Middleton-Levine model(briefly saying the BML model)is improved by removing its limitation of synchronized change of traffic lights.In new model,the traffic light at each crossing could arbitrarily change its starting time and tempo of variation and hence the model could more realistically describe the influence of traffic lights on the performance of traffic systems.The cases of traffic light with unsynchronized starting time and different tempo of variation are simulated in this paper.

  6. A Network Traffic Control Enhancement Approach over Bluetooth Networks

    DEFF Research Database (Denmark)

    Son, L.T.; Schiøler, Henrik; Madsen, Ole Brun;

    2003-01-01

    This paper analyzes network traffic control issues in Bluetooth data networks as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. An adaptive distributed network traffic control scheme is proposed as an approximated...... solution of the stated optimization problem that satisfies quality of service requirements and topologically induced constraints in Bluetooth networks, such as link capacity and node resource limitations. The proposed scheme is decentralized and complies with frequent changes of topology as well...... as capacity limitations and flow requirements in the network. Simulation shows that the performance of Bluetooth networks could be improved by applying the adaptive distributed network traffic control scheme...

  7. Limited sharing with traffic prediction for dynamic bandwidth allocation and QoS provisioning over Ethernet passive optical networks

    Science.gov (United States)

    Luo, Yuanqiu; Ansari, Nirwan

    2005-09-01

    Feature Issue on Optical Access Networks (OAN) As an inexpensive, simple, and scalable solution for broadband access, Ethernet passive optical networks (EPONs) have the capability of delivering integrated broadband services to the end users. A critical issue of EPONs is the utility of a shared upstream channel among the local users, and thus an efficient bandwidth allocation mechanism is required to facilitate statistical multiplexing among the local network traffic. In this paper we propose a dynamic bandwidth allocation scheme, i.e., limited sharing with traffic prediction (LSTP), for upstream channel sharing over EPONs. LSTP enables dynamic bandwidth negotiation between the optical line terminal (OLT) and its associated optical network units (ONUs), alleviates data delay by predicting the traffic arrived during the waiting time and prereserving a portion of bandwidth for delivery, and avoids the aggressive bandwidth competition by upper bounding the allocated bandwidth to each ONU. Theoretical analysis and simulation results verify the feasibility of LSTP by showing that LSTP outperforms other existing schemes with respect to QoS metrics of data delay and data loss.

  8. Real-Time Communication Support for Cooperative, Infrastructure-Based Traffic Safety Applications

    Directory of Open Access Journals (Sweden)

    Annette Böhm

    2011-01-01

    Full Text Available The implementation of ITS (Intelligent Transport Systems services offers great potential to improve the level of safety, efficiency and comfort on our roads. Although cooperative traffic safety applications rely heavily on the support for real-time communication, the Medium Access Control (MAC mechanism proposed for the upcoming IEEE 802.11p standard, intended for ITS applications, does not offer deterministic real-time support, that is, the access delay to the common radio channel is not upper bounded. To address this problem, we present a framework for a vehicle-to-infrastructure-based (V2I communication solution extending IEEE 802.11p by introducing a collision-free MAC phase assigning each vehicle an individual priority based on its geographical position, its proximity to potential hazards and the overall road traffic density. Our solution is able to guarantee the timely treatment of safety-critical data, while minimizing the required length of this real-time MAC phase and freeing bandwidth for best-effort services (targeting improved driving comfort and traffic efficiency. Furthermore, we target fast connection setup, associating a passing vehicle to an RSU (Road Side Unit, and proactive handover between widely spaced RSUs. Our real-time MAC concept is evaluated analytically and by simulation based on a realistic task set from a V2I highway merge assistance scenario.

  9. Virtualized Traffic at Metropolitan Scales

    Directory of Open Access Journals (Sweden)

    David eWilkie

    2015-05-01

    Full Text Available Few phenomena are more ubiquitous than traffic, and few are more significant economically, socially, or environmentally. Any virtual reality system, including virtual globes and immersive multi-player worlds that are set in a modern or futuristic setting feature traffic systems. Virtual reality models can also aid in addressing the challenges of real-world traffic systems, the ever-present gridlock and congestion in cities worldwide: traffic engineers and planners can diagnose system instabilities and explore control strategies in virtual worlds reconstructed from available sensor data. To create these systems, road network models need to be created and represented. Traffic needs to be realistically and efficiently simulated. To analyze real-world scenarios, the traffic conditions need to be estimated and reconstructed. To create virtual scenarios, such as simulated cities, traffic needs to be intelligently and efficiently routed.

  10. Web traffic and firm performance

    DEFF Research Database (Denmark)

    Farooq, Omar; Aguenaou, Samir

    2013-01-01

    Does the traffic generated by websites of firms signal anything to stock market participants? Does higher web-traffic translate into availability of more information and therefore lower agency problems? And if answers to above questions are in affirmative, does higher web-traffic traffic translate...... into better firm performance? This paper aims to answer these questions by documenting a positive relationship between the extent of web-traffic and firm performance in the MENA region during the 2010. We argue that higher web-traffic lowers the agency problems in firms by disseminating more information...... to stock market participants. Consequently, lower agency problems translate into better performance. Furthermore, we also show that agency reducing role of web-traffic is more pronounced in regimes where information environment is already bad. For example, our results show stronger impact of web...

  11. MERGING AND SPLITTING SECOND-ORDER SELF-SIMILAR PROCESSES (TRAFFICS)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Recent traffic measurements in corporate LANs, Variable-Bit-Rate (VBR) video sources, ISDN control channels, and other communication systems, have indicated traffic behavior of self-similar nature, which has implications for design, control and analysis of high-speed networks. Merging and splitting are two basic networking operations. This paper gave the necessary and sufficient conditions for that merging of second-order self-similar traffic streams also results in a second-order self-similar stream. It shows that splitting traffic streams of the second-order self-similar stream are still self-similar streams by the independent splitting operation.

  12. Road Traffic Noise

    Science.gov (United States)

    Beckenbauer, Thomas

    Road traffic is the most interfering noise source in developed countries. According to a publication of the European Union (EU) at the end of the twentieth century [1], about 40% of the population in 15 EU member states is exposed to road traffic noise at mean levels exceeding 55 dB(A). Nearly 80 million people, 20% of the population, are exposed to levels exceeding 65 dB(A) during daytime and more than 30% of the population is exposed to levels exceeding 55 dB(A) during night time. Such high noise levels cause health risks and social disorders (aggressiveness, protest, and helplessness), interference of communication and disturbance of sleep; the long- and short-term consequences cause adverse cardiovascular effects, detrimental hormonal responses (stress hormones), and possible disturbance of the human metabolism (nutrition) and the immune system. Even performance at work and school could be impaired.

  13. Dementia and Traffic Accidents

    DEFF Research Database (Denmark)

    Petersen, Jindong Ding; Siersma, Volkert; Nielsen, Connie Thurøe;

    2016-01-01

    BACKGROUND: As a consequence of a rapid growth of an ageing population, more people with dementia are expected on the roads. Little is known about whether these people are at increased risk of road traffic-related accidents. OBJECTIVE: Our study aims to investigate the risk of road traffic......-related accidents for people aged 65 years or older with a diagnosis of dementia in Denmark. METHODS: We will conduct a nationwide population-based cohort study consisting of Danish people aged 65 or older living in Denmark as of January 1, 2008. The cohort is followed for 7 years (2008-2014). Individual's personal...... data are available in Danish registers and can be linked using a unique personal identification number. A person is identified with dementia if the person meets at least one of the following criteria: (1) a diagnosis of the disease in the Danish National Patient Register or in the Danish Psychiatric...

  14. Physics of Traffic Flow

    Science.gov (United States)

    Davis, L. C.

    2015-03-01

    The Texas A&M Transportation Institute estimated that traffic congestion cost the United States 121 billion in 2011 (the latest data available). The cost is due to wasted time and fuel. In addition to accidents and road construction, factors contributing to congestion include large demand, instability of high-density free flow and selfish behavior of drivers, which produces self-organized traffic bottlenecks. Extensive data collected on instrumented highways in various countries have led to a better understanding of traffic dynamics. From these measurements, Boris Kerner and colleagues developed a new theory called three-phase theory. They identified three major phases of flow observed in the data: free flow, synchronous flow and wide moving jams. The intermediate phase is called synchronous because vehicles in different lanes tend to have similar velocities. This congested phase, characterized by lower velocities yet modestly high throughput, frequently occurs near on-ramps and lane reductions. At present there are only two widely used methods of congestion mitigation: ramp metering and the display of current travel-time information to drivers. To find more effective methods to reduce congestion, researchers perform large-scale simulations using models based on the new theories. An algorithm has been proposed to realize Wardrop equilibria with real-time route information. Such equilibria have equal travel time on alternative routes between a given origin and destination. An active area of current research is the dynamics of connected vehicles, which communicate wirelessly with other vehicles and the surrounding infrastructure. These systems show great promise for improving traffic flow and safety.

  15. Assessing road traffic expression

    OpenAIRE

    Fábio Silva; Cesar Analide; Paulo Novais

    2014-01-01

    Road traffic is a problem which is increasing in cities with large population. Unrelated to this fact the number of portable and wearable devices has also been increasing throughout the population of most countries. With this advent, the capacity to monitor and register data about people habits and locations as well as more complex data such as intensity and strength of movements has created an opportunity to contribute to the general wealth and comfort within these environments. Ambient Inte...

  16. Organic traffic control

    OpenAIRE

    Prothmann, Holger

    2011-01-01

    Modern cities cannot be imagined without traffic lights controlling the road network. To handle the network's changing demands efficiently, the signal plan specification needs to be shifted from the design time to the run-time of a signal system. The generic observer/controller architecture proposed for Organic Computing facilitates this shift. A two-levelled learning mechanism optimises signal plans on-line while a distributed coordination mechanism establishes green waves in the road network.

  17. Untieing the Traffic Knot

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Beijing is working to resolve its longtime transportation problems before the 2008 Olympics One traffic jam after another, annoying horns, endless lines of cars,impatient sighs from passengers on an overcrowded bus, the youstomped-on-my-toe quarreling in the subway train, all have led to the unsurprising result that Beijing scored at the tail end of a survey of 287 cities in the category of transport satisfaction in China’s 2006 Report on the Quality of Urban Life.

  18. Intelligent Video Traffic Smooth Mechanism for Multimedia Communication

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A principal challenge in supporting real-time video services over ATM is the need to provide synchronous play-out in the face of stochastic end-to-end network delays. In this paper, an intelligent traffic smooth mechanism ( ITSM ) is proposed to meet the continuity requirement which is composed of a back-propagation neural network ( BPNN ) traffic predictor, a play-out buffer, and a fuzzy neural network ( FNN ) based play-out rate determinator. The BPNN traffic predictor online predicts the mean packet rate of the traffic in the future interval ( FI ) and the FNN is designed to adaptively determinate the play-out time according to the number of packets in the buffer and the traffic character predicted. Simulation results show that compared to the window mechanism, ITSM achieves high continuity with accepted delay. Furthermore, ITSM can be adaptively modified to meet the QoS of different kinds of services by FNN parameter training.

  19. The Physics of Traffic

    Science.gov (United States)

    Davis, L. Craig

    2006-03-01

    Congestion in freeway traffic is an example of self-organization in the language of complexity theory. Nonequilibrium, first-order phase transitions from free flow cause complex spatiotemporal patterns. Two distinct phases of congestion are observed in empirical traffic data--wide moving jams and synchronous flow. Wide moving jams are characterized by stopped or slowly moving vehicles within the jammed region, which widens and moves upstream at 15-20 km/h. Above a critical density of vehicles, a sudden decrease in the velocity of a lead vehicle can initiate a transition from metastable states to this phase. Human behaviors, especially delayed reactions, are implicated in the formation of jams. The synchronous flow phase results from a bottleneck such as an on-ramp. Thus, in contrast to a jam, the downstream front is pinned at a fixed location. The name of the phase comes from the equilibration (or synchronization) of speed and flow rate across all lanes caused by frequent vehicle lane changes. Synchronous flow occurs when the mainline flow and the rate of merging from an on-ramp are sufficiently large. Large-scale simulations using car-following models reproduce the physical phenomena occurring in traffic and suggest methods to improve flow and mediate congestion.

  20. Assessing Road Traffic Expression

    Directory of Open Access Journals (Sweden)

    Fábio Silva

    2014-12-01

    Full Text Available Road traffic is a problem which is increasing in cities with large population. Unrelated to this fact the number of portable and wearable devices has also been increasing throughout the population of most countries. With this advent, the capacity to monitor and register data about people habits and locations as well as more complex data such as intensity and strength of movements has created an opportunity to contribute to the general wealth and comfort within these environments. Ambient Intelligence and Intelligent Decision Making processes can benefit from the knowledge gathered by these devices to improve decisions on everyday tasks such as deciding navigation routes by car, bicycle or other means of transportation and avoiding route perils. The concept of computational sustainability may also be applied to this problem. Current applications in this area demonstrate the usefulness of real time system that inform the user of certain conditions in the surrounding area. On the other hand, the approach presented in this work aims to describe models and approaches to automatically identify current states of traffic inside cities and use methods from computer science to improve overall comfort and the sustainability of road traffic both with the user and the environment in mind. Such objective is delivered by analyzing real time contributions from those mobile ubiquitous devices to identifying problematic situations and areas under a defined criteria that have significant influence towards a sustainable use of the road transport infrastructure.

  1. Dynamic multicast traffic grooming in WDM networks

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiao-jun; GE Ning; FENG Chong-xi

    2006-01-01

    Dynamic multicast traffic grooming in wavelength division multiplexing (WDM) networks was analyzed to minimize networkwide costs and to increase the network resource utilization.A network model was developed for dynamic multicast traffic grooming with resource constraints and an algorithm that can provide quality of service (QoS)was proposed.The QoS is measured by the maximum number of lightpaths passing between the source and the destinations.The blocking probability of the algorithm was assessed in simulations.The results show that a higher QoS requirement results in higher blocking probability,and when the QoS requirement is low,changes in the QoS requirements have only small effects on the blocking probability.

  2. Trace Analysis of Driver Behavior on Traffic Violator by Using Big Data (Traffic Program) in Korea

    OpenAIRE

    Lee, Jonghak

    2016-01-01

    This study aims to prove the effectiveness of traffic safety education program for traffic violators. Traffic violators who finished the traffic safety education programs were tracked down. In order to analyze the effectiveness of traffic safety education program, traffic violator’s data during ten-year period were used. This study analyzed how traffic violators changed their attitudes about traffic law abidance. Also predicted social benefits from traffic safety education program...

  3. Accurate Multisteps Traffic Flow Prediction Based on SVM

    Directory of Open Access Journals (Sweden)

    Zhang Mingheng

    2013-01-01

    Full Text Available Accurate traffic flow prediction is prerequisite and important for realizing intelligent traffic control and guidance, and it is also the objective requirement for intelligent traffic management. Due to the strong nonlinear, stochastic, time-varying characteristics of urban transport system, artificial intelligence methods such as support vector machine (SVM are now receiving more and more attentions in this research field. Compared with the traditional single-step prediction method, the multisteps prediction has the ability that can predict the traffic state trends over a certain period in the future. From the perspective of dynamic decision, it is far important than the current traffic condition obtained. Thus, in this paper, an accurate multi-steps traffic flow prediction model based on SVM was proposed. In which, the input vectors were comprised of actual traffic volume and four different types of input vectors were compared to verify their prediction performance with each other. Finally, the model was verified with actual data in the empirical analysis phase and the test results showed that the proposed SVM model had a good ability for traffic flow prediction and the SVM-HPT model outperformed the other three models for prediction.

  4. Distributed Trajectory Flexibility Preservation for Traffic Complexity Mitigation

    Science.gov (United States)

    Idris, Husni; Wing, David; Delahaye, Daniel

    2009-01-01

    The growing demand for air travel is increasing the need for mitigation of air traffic congestion and complexity problems, which are already at high levels. At the same time new information and automation technologies are enabling the distribution of tasks and decisions from the service providers to the users of the air traffic system, with potential capacity and cost benefits. This distribution of tasks and decisions raises the concern that independent user actions will decrease the predictability and increase the complexity of the traffic system, hence inhibiting and possibly reversing any potential benefits. In answer to this concern, the authors propose the introduction of decision-making metrics for preserving user trajectory flexibility. The hypothesis is that such metrics will make user actions naturally mitigate traffic complexity. In this paper, the impact of using these metrics on traffic complexity is investigated. The scenarios analyzed include aircraft in en route airspace with each aircraft meeting a required time of arrival in a one-hour time horizon while mitigating the risk of loss of separation with the other aircraft, thus preserving its trajectory flexibility. The experiments showed promising results in that the individual trajectory flexibility preservation induced self-separation and self-organization effects in the overall traffic situation. The effects were quantified using traffic complexity metrics based on Lyapunov exponents and traffic proximity.

  5. CATS-based Air Traffic Controller Agents

    Science.gov (United States)

    Callantine, Todd J.

    2002-01-01

    This report describes intelligent agents that function as air traffic controllers. Each agent controls traffic in a single sector in real time; agents controlling traffic in adjoining sectors can coordinate to manage an arrival flow across a given meter fix. The purpose of this research is threefold. First, it seeks to study the design of agents for controlling complex systems. In particular, it investigates agent planning and reactive control functionality in a dynamic environment in which a variety perceptual and decision making skills play a central role. It examines how heuristic rules can be applied to model planning and decision making skills, rather than attempting to apply optimization methods. Thus, the research attempts to develop intelligent agents that provide an approximation of human air traffic controller behavior that, while not based on an explicit cognitive model, does produce task performance consistent with the way human air traffic controllers operate. Second, this research sought to extend previous research on using the Crew Activity Tracking System (CATS) as the basis for intelligent agents. The agents use a high-level model of air traffic controller activities to structure the control task. To execute an activity in the CATS model, according to the current task context, the agents reference a 'skill library' and 'control rules' that in turn execute the pattern recognition, planning, and decision-making required to perform the activity. Applying the skills enables the agents to modify their representation of the current control situation (i.e., the 'flick' or 'picture'). The updated representation supports the next activity in a cycle of action that, taken as a whole, simulates air traffic controller behavior. A third, practical motivation for this research is to use intelligent agents to support evaluation of new air traffic control (ATC) methods to support new Air Traffic Management (ATM) concepts. Current approaches that use large, human

  6. Robust and reactive traffic engineering for dynamic traffic demands

    OpenAIRE

    Casas Hernandez, Pedro; Fillatre, Lionel; Vaton, Sandrine

    2008-01-01

    Traffic engineering (TE) has become a challenging mechanism for network management and resources optimization due to uncertain and difficult to predict traffic patterns. Recent works have proposed robust optimization techniques to cope with uncertain traffic, computing a stable routing configuration that is immune to demand variations within certain uncertainty set. However, using a single routing configuration for longtime periods can be highly inefficient. Even more, the presence of abnorma...

  7. Dividing the Traffic Matrix to Approach Optimal Traffic Engineering

    OpenAIRE

    Balon, Simon; Leduc, Guy

    2006-01-01

    In this paper we propose a new method to approach optimal Traffic Engineering routing. The method consists of dividing the traffic matrix into $N$ sub-matrices, called strata, and route each of these independently. We propose two different implementations of our method in routers. Our method can also be used to compute a very precise approximation of the optimal value of a given objective function for comparison to heuristic Traffic Engineering algorithms. For this application, our algorithm ...

  8. Traffic Data and Their Implications for Consistent Traffic Flow Modeling

    OpenAIRE

    Helbing, Dirk

    1998-01-01

    The paper analyzes traffic data of the Dutch freeway A9 with respect to certain aspects which are relevant for traffic flow modeling as well as the calibration of model parameters and functions. Apart from the dynamic velocity distribution, the density-dependence and the temporal evolution of various, partly lane-specific quantities is investigated. The results are well compatible with recent macroscopic traffic flow models which have been derived from the dynamics of driver-vehicle units. Th...

  9. Evaluation of Traffic Management Measures on Road Traffic Noise

    OpenAIRE

    Bhaskar, A.; Chung, E; Dumont, A.-G.

    2006-01-01

    Road traffic noise affects the quality of life in the areas adjoining the road. The effect of traffic noise on people is wide ranging and may include sleep disturbance and negative impact on work efficiency. To address the problem of traffic noise, it is necessary to estimate the noise level. For this, a number of noise estimation models have been developed which can estimate noise at the receptor points, based on simple configuration of buildings. Howe...

  10. Lagrangian Multi-Class Traffic State Estimation

    OpenAIRE

    Y. Yuan

    2013-01-01

    Road traffic is important to everybody in the world. People travel and commute everyday. For those who travel by cars (or other types of road vehicles), traffic congestion is a daily experience. One essential goal of traffic researchers is to reduce traffic congestion and to improve the whole traffic system operation and the environment. To achieve this goal, we have to first understand prevailing traffic situations, then perform pro-active traffic control and management. The estimation of tr...

  11. HIERARCHICAL GENETIC ALGORITHM FOR DYNAMIC CHANNEL UNITS ALLOCATION IN TDCDMA/ TDD SYSTEM

    Directory of Open Access Journals (Sweden)

    Kuo-Ming Hung

    2009-11-01

    Full Text Available Hierarchical Genetic Algorithms (HGA as a tool for search and optimizing methodology have now reached a mature stage. The minimum resource facility to carry user traffic, termed a channel unit (CU,is composed of a one time-slot and one code in the TD-CDMA/TDD system. The control of the number of CUs depends on the traffic load solves varied and asymmetrical traffic problems in the 3G system. In acellular network, the call arrival rate, call duration and the communication overhead between the base stations and the control center are vague and uncertain, regardless of whether the criteria of concern are nonlinear, constrained, discrete or NP hard. In this paper, the HGA is used to tackle the neural network (NN topology as well as the fuzzy logic controller for the dynamic CU allocation scheme in wireless cellular networks. Therefore, we propose a new efficient HGA CUs Allocation (HGACA in cellular networks. It aims to efficiently satisfy the diverse quality-of-service (QoS requirements of multimedia traffic. The results show our algorithm has a lower blocking rate, lower dropping rate, less update overhead, and shorter channel-acquisition delay than previous methods.

  12. Handling Deafness Problem of Scheduled Multi-Channel Polling MACs

    Science.gov (United States)

    Jiang, Fulong; Liu, Hao; Shi, Longxing

    Combining scheduled channel polling with channel diversity is a promising way for a MAC protocol to achieve high energy efficiency and performance under both light and heavy traffic conditions. However, the deafness problem may cancel out the benefit of channel diversity. In this paper, we first investigate the deafness problem of scheduled multi-channel polling MACs with experiments. Then we propose and evaluate two schemes to handle the deafness problem. Our experiment shows that deafness is a significant reason for performance degradation in scheduled multi-channel polling MACs. A proper scheme should be chosen depending on the traffic pattern and the design objective.

  13. Traffic forecasts ignoring induced demand

    DEFF Research Database (Denmark)

    Næss, Petter; Nicolaisen, Morten Skou; Strand, Arvid

    2012-01-01

    Although the phenomenon of induced traffic has been theorized for more than 60 years and is now widely accepted among transport researchers, the traffic-generating effects of road capacity expansion are still often neglected in transport modelling. Such omission can lead to serious bias...... performance of a proposed road project in Copenhagen with and without short-term induced traffic included in the transport model. The available transport model was not able to include long-term induced traffic resulting from changes in land use and in the level of service of public transport. Even though...... the model calculations included only a part of the induced traffic, the difference in cost-benefit results compared to the model excluding all induced traffic was substantial. The results show lower travel time savings, more adverse environmental impacts and a considerably lower benefitcost ratio when...

  14. Research on Prediction of Traffic Congestion State

    Directory of Open Access Journals (Sweden)

    Zhao Jun

    2015-01-01

    Full Text Available This method of prediction using the data mining to analyze huge amounts of data as a preferred tool has been widely used in various fields. In the midst of it, the routine traffic data exists in a large number of isolated data in real time without establishing relationships with other data, and detects the amount of data which is greater than that at present. The usage of these data which is relatively shallow requires an in-depth analysis of its data model. Therefore, this paper uses a fuzzy clustering analysis method of feature points to study the traffic flow, uses a Markov decision chain model to study traffic jams, uses quantitative sample points based on the information entropy to calculate traffic flow trends and uses a heuristic prediction model to predict the road con-gestion. Through the simulation experiment which verifies the correctness of the model, this research is to advance the development of the road and to provide a basis for a dredging plan.

  15. Interdomain traffic engineering with BGP

    OpenAIRE

    Quoitin, Bruno; Uhlig, Steve; Pelsser, Cristel; Swinnen, Louis; Bonaventure, Olivier

    2003-01-01

    Traffic engineering is performed by means of a set of techniques that can be used to better control the flow of packets inside an IP network We discuss the utilization of these techniques across interdomain boundaries in the global Internet. We first analyze the characteristics of interdomain traffic on the basis of measurements from three different Internet service providers and show that a small number of sources are responsible for a large fraction of the traffic. Across interdomain bounda...

  16. Framework for Traffic Congestion Management

    OpenAIRE

    Mahmud Hassan TALUKDAR

    2013-01-01

    Traffic Congestion is one of many serious global problems in all great cities resulted from rapid urbanization which always exert negative externalities upon society. The solution of traffic congestion is highly geocentric and due to its heterogeneous nature, curbing congestion is one of the hard tasks for transport planners. It is not possible to suggest unique traffic congestion management framework which could be absolutely applied for every great cities. Conversely, it is quite feasible t...

  17. Traffic noise and cardiovascular disease

    OpenAIRE

    Selander, Jenny

    2010-01-01

    Traffic noise is an increasing problem in urban areas worldwide, but health effects in relation to traffic noise exposure are not well understood. Several studies show that noise may give rise to acute stress reactions, possibly leading to cardiovascular effects, but the evidence is limited on cardiovascular risks associated with traffic noise exposure. Cardiovascular effects have been indicated for other environmental stressors such as occupational noise exposure and job ...

  18. Estimating Emissions from Railway Traffic

    DEFF Research Database (Denmark)

    Jørgensen, Morten W.; Sorenson, Spencer C.

    1998-01-01

    Several parameters of importance for estimating emissions from railway traffic are discussed, and typical results presented. Typical emissions factors from diesel engines and electrical power generation are presented, and the effect of differences in national electrical generation sources...... illustrated as well as the degree of electrification for different countries. Traffic parameters such as passenger occupancy rates, per capita freight and passenger traffic are presented for European conditions. The relationship between average train speed and distance between stops is shown for a variety...

  19. Road traffic injuries

    Institute of Scientific and Technical Information of China (English)

    WANG Zheng-guo 王正国

    2003-01-01

    @@ The appearance of cars has raised materialistic civilization and living standard to an unprecedented level. Today, it is hard to imagine how we human beings can live without cars.Yet, motor vehicles can cause a great number of deaths and injuries as well as considerable economic losses, which have constituted the global burden. Understanding of the occurrence and development of road traffic injuries will contribute to the prevention and control of crash and to the implementation of "everybody has the right to enjoy health" proposed by WHO.

  20. Road traffic noise and stroke

    DEFF Research Database (Denmark)

    Sørensen, Mette; Hvidberg, Martin; Andersen, Zorana J;

    2011-01-01

    Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before.......Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before....

  1. A Modified Efficient Traffic Scheduling Algorithm for Routing in Optical WDM Mesh Networks

    Science.gov (United States)

    Kavitha, T.; Rajamani, V.

    2013-09-01

    This paper is proposing an efficient traffic scheduling for routing in optical networks supported by Wavelength Division Multiplexing (WDM). Normally the traffic is routed through the primary path or back-up path towards the destination. In order to meet the transmission of higher data rates, the path of the WDM should be capable of carrying the traffic without any failure. Whenever the transmission through primary or backup path fails due to excessive overhead or network failure or congestion or excessive load, existing router mechanisms are not scheduling the traffic in an effective manner. This paper deals with an efficient traffic scheduling algorithm which effectively routes the traffic using multipath technique that satisfies the optical constraints. The whole procedure of routing algorithm is separated into two phases: the connection node establishment phase and multipath transmission from the connection node to destination phase. The connection node is selected on the basis of load and current traffic carrying capacity of that node. Then the traffic is routed to the destination using multiple paths. The proposed method tries to minimize the blocking probability of 70% compared to the existing Resource Efficiency Factor (REF) algorithm and also increase the throughput of 30% and better channel utilization of 23% based on data rate and 20% based on traffic time interval. Hence, the proposed algorithm is effectively routes the traffic within the network.

  2. FPGA Based Real-time Network Traffic Analysis using Traffic Dispersion Patterns

    Energy Technology Data Exchange (ETDEWEB)

    Khan, F; Gokhale, M; Chuah, C N

    2010-03-26

    The problem of Network Traffic Classification (NTC) has attracted significant amount of interest in the research community, offering a wide range of solutions at various levels. The core challenge is in addressing high amounts of traffic diversity found in today's networks. The problem becomes more challenging if a quick detection is required as in the case of identifying malicious network behavior or new applications like peer-to-peer traffic that have potential to quickly throttle the network bandwidth or cause significant damage. Recently, Traffic Dispersion Graphs (TDGs) have been introduced as a viable candidate for NTC. The TDGs work by forming a network wide communication graphs that embed characteristic patterns of underlying network applications. However, these patterns need to be quickly evaluated for mounting real-time response against them. This paper addresses these concerns and presents a novel solution for real-time analysis of Traffic Dispersion Metrics (TDMs) in the TDGs. We evaluate the dispersion metrics of interest and present a dedicated solution on an FPGA for their analysis. We also present analytical measures and empirically evaluate operating effectiveness of our design. The mapped design on Virtex-5 device can process 7.4 million packets/second for a TDG comprising of 10k flows at very high accuracies of over 96%.

  3. Differential effects of traffic sign stimuli upon speeding in school zones following a traffic light interruption.

    Science.gov (United States)

    Gregory, Bree; Irwin, Julia D; Faulks, Ian J; Chekaluk, Eugene

    2016-01-01

    Motorists whose journey has been interrupted by signalized traffic intersections in school zones resume their journey at a faster vehicle speed than motorists who have not been required to stop. Introducing a flashing "check speed" sign 70m after the traffic intersections counteracts this interruptive effect. The present study examined which aspects of a reminder sign are responsible for reducing the speeding behavior of interrupted motorists. When a sign that combines both written text and flashing lights was introduced, interrupted motorists did not speed, traveling on average 0.82km/h below the 40km/h speed limit when measured 100m from traffic intersections. Alternatively, when only the flashing lights were visible the interrupted motorists sped 3.36km/h over the 40km/h speed limit. Similar vehicular speeds were observed when only the written text was visible and when no sign was present (7.67 and 7.49km/h over the 40km/h speed limit, respectively). This indicates that static reminder signs add little value over the absence of a school zone reminder sign; the presence of both cues is necessary to fully offset the interruptive effect. This study also highlights the benefit of using exogenous visual cues in traffic signs to capture drivers' attention. These findings have practical implications for the design and use of traffic signs to increase compliance with posted speed limits. PMID:26545011

  4. A shared data environment for the Military Traffic Management Command Directorate of International Traffic

    Energy Technology Data Exchange (ETDEWEB)

    Russell, D.L.; Wheeler, V.V. (Tennessee Univ., Knoxville, TN (United States)); Truett, L.F. (Oak Ridge National Lab., TN (United States))

    1992-01-01

    In September 1991, Oak Ridge National Laboratory (ORNL) completed tasking to assist the Military Traffic Management Command Directorate of International Traffic (MTIT) in the analysis of a potential Shared Data Environment (SDE) for MTIT automated cargo traffic systems. This analysis was a preliminary effort with emphasis on documentation of requirements, examination of design alternatives, and identification of specific MTIT systems' data sharing problems. This report records the results of the ORNL analysis. The SDE envisioned by ORNL at this point in the analysis is not merely a repository of information; it is also a system that allows processing of distributed data. To provide high-level access to and control over international cargo processes, ORNL recommends a loosely coupled, replicated database design with high-speed communications among all sites.

  5. A shared data environment for the Military Traffic Management Command Directorate of International Traffic

    Energy Technology Data Exchange (ETDEWEB)

    Russell, D.L.; Wheeler, V.V. [Tennessee Univ., Knoxville, TN (United States); Truett, L.F. [Oak Ridge National Lab., TN (United States)

    1992-01-01

    In September 1991, Oak Ridge National Laboratory (ORNL) completed tasking to assist the Military Traffic Management Command Directorate of International Traffic (MTIT) in the analysis of a potential Shared Data Environment (SDE) for MTIT automated cargo traffic systems. This analysis was a preliminary effort with emphasis on documentation of requirements, examination of design alternatives, and identification of specific MTIT systems` data sharing problems. This report records the results of the ORNL analysis. The SDE envisioned by ORNL at this point in the analysis is not merely a repository of information; it is also a system that allows processing of distributed data. To provide high-level access to and control over international cargo processes, ORNL recommends a loosely coupled, replicated database design with high-speed communications among all sites.

  6. Trace Analysis of Driver Behavior on Traffic Violator by Using Big Data (Traffic Program in Korea

    Directory of Open Access Journals (Sweden)

    Lee, Jonghak

    2016-01-01

    Full Text Available This study aims to prove the effectiveness of traffic safety education program for traffic violators. Traffic violators who finished the traffic safety education programs were tracked down. In order to analyze the effectiveness of traffic safety education program, traffic violator’s data during ten-year period were used. This study analyzed how traffic violators changed their attitudes about traffic law abidance. Also predicted social benefits from traffic safety education program for traffic violators. Effectiveness of traffic accident prevention through traffic safety education program is approximately 93%. In terms of social benefits, it shows more than $12 billion Even though the effectiveness of traffic safety education program represents remarkable results, but this program is made for traffic violators who have already committed traffic offenses in the past. So in order to prevent traffic violations in advance, specific education program for potentially risky drivers is necessary.

  7. Switch Based Opportunistic Spectrum Access for General Primary User Traffic Model

    KAUST Repository

    Gaaloul, Fakhreddine

    2012-06-18

    This letter studies cognitive radio transceiver that can opportunistically use the available channels of primary user (PU). Specifically, we investigate and compare two different opportunistic channel access schemes. The first scheme applies when the secondary user (SU) has access to only one channel. The second scheme, based on channel switching mechanism, applies when the SU has access to multiple channels but can at a given time monitor and access only one channel. For these access schemes, we derive the exact analytical results for the novel performance metrics of average access time and average waiting time under general PU traffic models.

  8. Measuring the Complexity of Self-organizing Traffic Lights

    CERN Document Server

    Zubillaga, Dario; Aguilar, Luis Daniel; Zapotecatl, Jorge; Fernandez, Nelson; Aguilar, Jose; Rosenblueth, David A; Gershenson, Carlos

    2014-01-01

    We apply measures of complexity, emergence and self-organization to an abstract city traffic model for comparing a traditional traffic coordination method with a self-organizing method in two scenarios: cyclic boundaries and non-orientable boundaries. We show that the measures are useful to identify and characterize different dynamical phases. It becomes clear that different operation regimes are required for different traffic demands. Thus, not only traffic is a non-stationary problem, which requires controllers to adapt constantly. Controllers must also change drastically the complexity of their behavior depending on the demand. Based on our measures, we can say that the self-organizing method achieves an adaptability level comparable to a living system.

  9. Web Conferencing Traffic - An Analysis Using DIMDIM as Example

    Directory of Open Access Journals (Sweden)

    Patrick Seeling

    2010-11-01

    Full Text Available In this paper, we present an evaluation of the Ethernet traffic for host and attendees of the popular opensourceweb conferencing system DimDim. While traditional Internet-centric approaches such as theMBONE have been used over the past decades, current trends for web-based conference systems makeexclusive use of application-layer multicast. To allow for network dimensioning and QoS provisioning, anunderstanding of the underlying traffic characteristics is required.We find in our exemplary evaluations that the host of a web conference session produces a large amountof Ethernet traffic, largely due to the required control of the conference session, that is heavily-taileddistributed and exhibits additionally long-range dependence. For different groups of activities within aweb conference session, we find distinctive characteristics of the generated traffic.

  10. Real Time Traffic Models, Decision Support for Traffic Management

    NARCIS (Netherlands)

    Wismans, L.; De Romph, E.; Friso, K.; Zantema, K.

    2014-01-01

    Reliable and accurate short-term traffic state prediction can improve the performance of real-time traffic management systems significantly. Using this short-time prediction based on current measurements delivered by advanced surveillance systems will support decision-making processes on various con

  11. Large scale traffic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Nagel, K.; Barrett, C.L. [Los Alamos National Lab., NM (United States)]|[Santa Fe Institute, NM (United States); Rickert, M. [Los Alamos National Lab., NM (United States)]|[Universitaet zu Koeln (Germany)

    1997-04-01

    Large scale microscopic (i.e. vehicle-based) traffic simulations pose high demands on computational speed in at least two application areas: (i) real-time traffic forecasting, and (ii) long-term planning applications (where repeated {open_quotes}looping{close_quotes} between the microsimulation and the simulated planning of individual person`s behavior is necessary). As a rough number, a real-time simulation of an area such as Los Angeles (ca. 1 million travellers) will need a computational speed of much higher than 1 million {open_quotes}particle{close_quotes} (= vehicle) updates per second. This paper reviews how this problem is approached in different projects and how these approaches are dependent both on the specific questions and on the prospective user community. The approaches reach from highly parallel and vectorizable, single-bit implementations on parallel supercomputers for Statistical Physics questions, via more realistic implementations on coupled workstations, to more complicated driving dynamics implemented again on parallel supercomputers. 45 refs., 9 figs., 1 tab.

  12. On 1-qubit channels

    OpenAIRE

    Uhlmann, Armin

    2000-01-01

    The entropy H_T(rho) of a state rho with respect to a channel T and the Holevo capacity of the channel require the solution of difficult variational problems. For a class of 1-qubit channels, which contains all the extremal ones, the problem can be significantly simplified by associating an Hermitian antilinear operator theta to every channel of the considered class. The concurrence of the channel can be expressed by theta and turns out to be a flat roof. This allows to write down an explicit...

  13. On 1-qubit channels

    CERN Document Server

    Uhlmann, A

    2001-01-01

    The entropy H_T(rho) of a state rho with respect to a channel T and the Holevo capacity of the channel require the solution of difficult variational problems. For a class of 1-qubit channels, which contains all the extremal ones, the problem can be significantly simplified by associating an Hermitian antilinear operator theta to every channel of the considered class. The concurrence of the channel can be expressed by theta and turns out to be a flat roof. This allows to write down an explicit expression for H_T. Its maximum would give the Holevo (1-shot) capacity.

  14. Fastlane: Traffic flow modeling and multi-class dynamic traffic management

    OpenAIRE

    Schreiter, T.; Van Wageningen-Kessels, F.L.M.; Yuan, Y; Lint, van J. W. C.; Hoogendoorn, S.P.

    2012-01-01

    Dynamic Traffic Management (DTM) aims to improve traffic conditions. DTM usually consists of two steps: first the current traffic is estimated, then appropriate control actions are determined based on that estimate. In order to estimate and control the traffic, a suitable traffic flow model that reproduces the properties of traffic well must be used. One of the most important properties is that traffic is composed of multiple vehicle classes. While many traffic flow models have been proposed ...

  15. A Survey of Network Optimization Techniques for Traffic Engineering

    OpenAIRE

    Fedrigo, Enrico; Granelli, Fabrizio

    2008-01-01

    TCP/IP represents the reference standard for the implementation of interoperable communication networks. Nevertheless, the layering principle at the basis of interoperability severely limits the performance of data communication networks, thus requiring proper configuration and management in order to provide effective management of traffic flows. This paper presents a brief survey related to network optimization using Traffic Engineering algorithms, aiming at providing additional insight to t...

  16. Congestion transition in air traffic networks.

    Science.gov (United States)

    Monechi, Bernardo; Servedio, Vito D P; Loreto, Vittorio

    2015-01-01

    Air Transportation represents a very interesting example of a complex techno-social system whose importance has considerably grown in time and whose management requires a careful understanding of the subtle interplay between technological infrastructure and human behavior. Despite the competition with other transportation systems, a growth of air traffic is still foreseen in Europe for the next years. The increase of traffic load could bring the current Air Traffic Network above its capacity limits so that safety standards and performances might not be guaranteed anymore. Lacking the possibility of a direct investigation of this scenario, we resort to computer simulations in order to quantify the disruptive potential of an increase in traffic load. To this end we model the Air Transportation system as a complex dynamical network of flights controlled by humans who have to solve potentially dangerous conflicts by redirecting aircraft trajectories. The model is driven and validated through historical data of flight schedules in a European national airspace. While correctly reproducing actual statistics of the Air Transportation system, e.g., the distribution of delays, the model allows for theoretical predictions. Upon an increase of the traffic load injected in the system, the model predicts a transition from a phase in which all conflicts can be successfully resolved, to a phase in which many conflicts cannot be resolved anymore. We highlight how the current flight density of the Air Transportation system is well below the transition, provided that controllers make use of a special re-routing procedure. While the congestion transition displays a universal scaling behavior, its threshold depends on the conflict solving strategy adopted. Finally, the generality of the modeling scheme introduced makes it a flexible general tool to simulate and control Air Transportation systems in realistic and synthetic scenarios. PMID:25993476

  17. Traffic Based Optimization of Spectrum Sensing in Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Changhua Yao

    2014-01-01

    Full Text Available We propose a more practical spectrum sensing optimization problem in cognitive radio networks (CRN, by considering the data traffic of second user (SU. Compared with most existing work, we do not assume that SU always has packets to transmit; instead, we use the actual data transmitted per second rather than the channel capacity as the achievable throughput, to reformulate the Sensing-Throughput Tradeoff problem. We mathematically analyze the problem of optimal sensing time to maximize the achievable throughput, based on the data traffic of SU. Our model is more general because the traditional Sensing-Throughput Tradeoff model can be seen as a special case of our model. We also prove that the throughput is a concave function of sensing time and there is only one optimal sensing time value which is determined by the data traffic. Simulation results show that the proposed approach outperforms existing methods.

  18. Traffic flow modeling: a Genealogy

    NARCIS (Netherlands)

    Van Wageningen-Kessels, F.L.M.; Hoogendoorn, S.P.; Vuik, C.; Van Lint, J.W.C.

    2014-01-01

    80 years ago, Bruce Greenshields presented the first traffic flow model at the Annual Meeting of the Highway Research Board. Since then, many models and simulation tools have been developed. We show a model tree with four families of traffic flow models, all descending from Greenshields' model. The

  19. Reports on internet traffic statistics

    NARCIS (Netherlands)

    Hoogesteger, Martijn; Oliveira Schmidt, de Ricardo; Sperotto, Anna; Pras, Aiko

    2013-01-01

    Internet traffic statistics can provide valuable information to network analysts and researchers about the way nowadays networks are used. In the past, such information was provided by Internet2 in a public website called Internet2 NetFlow: Weekly Reports. The website reported traffic statistics fro

  20. Transitions towards sustainable traffic management

    NARCIS (Netherlands)

    Wilmink, I.; Immers, B.; Potters, P.; Knaap, R. van der

    2006-01-01

    Traffic management (TM) has come a long way over the past years. However, several problems inhibit further development of traffic management and the large-scale implementation of successful pilot projects with innovative TM solutions. Given the still increasing mobility and its undesirable side-effe

  1. Optimizing urban traffic control using a rational agent

    Institute of Scientific and Technical Information of China (English)

    Salvador IBARRA-MARTÍNEZ; José A. CASTÁN-ROCHA; Julio LARIA-MENCHACA

    2014-01-01

    This paper is devoted to developing and evaluating a set of technologies with the objective of designing a method-ology for the implementation of sophisticated traffic lights by means of rational agents. These devices would be capable of op-timizing the behavior of a junction with multiple traffic signals, reaching a higher level of autonomy without losing reliability, accuracy, or efficiency in the offered services. In particular, each rational agent in a traffic signal will be able to analyze the requirements and constraints of the road, in order to know its level of demand. With such information, the rational agent will adapt its light cycles with the view of accomplishing more fluid traffic patterns and minimizing the pollutant environmental emissions produced by vehicles while they are stopped at a red light, through using a case-based reasoning (CBR) adaptation. This paper also integrates a microscopic simulator developed to run a set of tests in order to compare the presented methodology with traditional traffic control methods. Two study cases are shown to demonstrate the efficiency of the introduced approach, increasing vehicular mobility and reducing harmful activity for the environment. For instance, in the first scenario, taking into account the studied traffic volumes, our approach increases mobility by 23%and reduces emissions by 35%. When the roads are managed by sophisticated traffic lights, a better level of service and considerable environmental benefits are achieved, demon-strating the utility of the presented approach.

  2. Analysis of Trajectory Flexibility Preservation Impact on Traffic Complexity

    Science.gov (United States)

    Idris, Husni; El-Wakil, Tarek; Wing, David J.

    2009-01-01

    The growing demand for air travel is increasing the need for mitigation of air traffic congestion and complexity problems, which are already at high levels. At the same time new information and automation technologies are enabling the distribution of tasks and decisions from the service providers to the users of the air traffic system, with potential capacity and cost benefits. This distribution of tasks and decisions raises the concern that independent user actions will decrease the predictability and increase the complexity of the traffic system, hence inhibiting and possibly reversing any potential benefits. In answer to this concern, the authors proposed the introduction of decision-making metrics for preserving user trajectory flexibility. The hypothesis is that such metrics will make user actions naturally mitigate traffic complexity. In this paper, the impact of using these metrics on traffic complexity is investigated. The scenarios analyzed include aircraft in en route airspace with each aircraft meeting a required time of arrival in a one-hour time horizon while mitigating the risk of loss of separation with the other aircraft, thus preserving its trajectory flexibility. The experiments showed promising results in that the individual trajectory flexibility preservation induced self-separation and self-organization effects in the overall traffic situation. The effects were quantified using traffic complexity metrics, namely dynamic density indicators, which indicated that using the flexibility metrics reduced aircraft density and the potential of loss of separation.

  3. Dissociative Tendencies and Traffic Incidents

    Directory of Open Access Journals (Sweden)

    Valle, Virginia

    2012-01-01

    Full Text Available This paper analyses the relationship between dissociative experiences and road traffic incidents (crashes and traffic tickets in drivers (n=295 from Mar del Plata (Argentina city. A self-report questionnaire was applied to assess traffic crash involvement and sociodemographic variables. Dissociative tendencies were assessed by a modified version of the DES scale. To examine differences in DES scores tests of the difference of means were applied. Drivers who reported to be previously involved in traffic incidents obtained higher puntuations in the dissociative experiences scale than drivers who did not report such events. This result is observed for the total scale and for the three sub-scales (absorption, amnesia and depersonalization. However, differences appeared mainly for minor damage collisions. Further studies are needed to evaluate the role of dissociative tendencies as a risk factor in road traffic safety.

  4. Basic model for traffic interweave

    Science.gov (United States)

    Huang, Ding-wei

    2015-09-01

    We propose a three-parameter traffic model. The system consists of a loop with two junctions. The three parameters control the inflow, the outflow (from the junctions,) and the interweave (in the loop.) The dynamics is deterministic. The boundary conditions are stochastic. We present preliminary results for a complete phase diagram and all possible phase transitions. We observe four distinct traffic phases: free flow, congestion, bottleneck, and gridlock. The proposed model is able to present economically a clear perspective to these four different phases. Free flow and congestion are caused by the traffic conditions in the junctions. Both bottleneck and gridlock are caused by the traffic interweave in the loop. Instead of directly related to conventional congestion, gridlock can be taken as an extreme limit of bottleneck. This model can be useful to clarify the characteristics of traffic phases. This model can also be extended for practical applications.

  5. Traffic Impact Simulation for Road Construction Project

    OpenAIRE

    Yazao Yang; Xiaoni Hao; Junshao Luo

    2012-01-01

    With the increasing traffic contradiction between supply and demand, urban traffic problems have become quite complex. Reasons for traffic congestion have become much more diverse. During the construction of urban road project, the surrounding road network will encounter a huge impact, traffic problems therefore emerged. Simulation is an important means for transport impact assessment, which has an important role for construction traffic impact analysis. Accordingly, traffic simulation i...

  6. Traffic Matrix Reloaded: Impact of Routing Changes

    OpenAIRE

    Teixeira, Renata; Duffield, Nick; Rexford, Jennifer; Roughan, Matthew

    2005-01-01

    International audience A traffic matrix represents the load from each ingress point to each egress point in an IP network. Although networks are engineered to tolerate some variation in the traffic matrix, large changes can lead to congested links and poor performance. The variations in the traffic matrix are caused by statistical fluc-tuations in the traffic entering the network and shifts in where the traffic leaves the network. For an accurate view of how the traffic matrix evolves over...

  7. An Open-Source Microscopic Traffic Simulator

    OpenAIRE

    Treiber, Martin; Kesting, Arne

    2010-01-01

    We present the interactive Java-based open-source traffic simulator available at www.traffic-simulation.de. In contrast to most closed-source commercial simulators, the focus is on investigating fundamental issues of traffic dynamics rather than simulating specific road networks. This includes testing theories for the spatiotemporal evolution of traffic jams, comparing and testing different microscopic traffic models, modeling the effects of driving styles and traffic rules on the efficiency ...

  8. Traffic Survey Techniques Study Based on the Freight Vehicles GPS Data%基于货运车辆GPS数据的交通调查技术研究

    Institute of Scientific and Technical Information of China (English)

    詹起林; 高峻; 王磊

    2011-01-01

    基于GPS轨迹点与道路网络拓扑数据,利用GIS技术进行OD点和交通通道的调查研究.利用货运车辆GPS轨迹数据,分析轨迹点的时间、速度及其空间分布特征,实验并确定合理的阈值过滤出点簇,生成OD点;用轨迹点捕获含有拓扑关系的临近路段,通过最短路径算法生成货运车辆沿道路的线型轨迹,最终获得完整的货运车辆出行通道调查数据.与传统交通调查方法相比,该方法的组织实施环节大大减少,调查数据和成果更加客观可靠,是一种通过信息技术进行交通调查研究的全新尝试.%Traffic survey is the foundation of urban transportation plan, construction and management. In the traditional study of traffic survey,a lot of manpower and material resources are required. After studying the research progress in the traffic survey,based on the GPS track points, road network topology data, and GIS technology, traffic technology research of OD points and traffic channel was realized in this paper. 1) By using freight vehicles GPS track data under customs' monitoring, the time, speed and mileage information of track point, and the spatial distribution characteristics about these track points were analyzed, by determining a reasonable threshold to filter out the cluster of stop points, and then traffic OD points were generated. 2) GPS track points can be captured to the nearest road, it can obtain the linear track of freight vehicles travelling through the shortest path algorithm. Additional the road sections without any track points recorded were collected to produce a complete vehicle traffic channel travel during freight vehicles driving. 3) In the end,it calculated the channel operation data combined with track points GPS attribute information on the channel. The traffic survey technology was used in the fourth comprehensive traffic survey in Shanghai, ultimately got a number of achievements that reflect traffic conditions, for example the OD

  9. Application of Chaos Theory in the Prediction of Motorised Traffic Flows on Urban Networks

    Directory of Open Access Journals (Sweden)

    Aderemi Adewumi

    2016-01-01

    Full Text Available In recent times, urban road networks are faced with severe congestion problems as a result of the accelerating demand for mobility. One of the ways to mitigate the congestion problems on urban traffic road network is by predicting the traffic flow pattern. Accurate prediction of the dynamics of a highly complex system such as traffic flow requires a robust methodology. An approach for predicting Motorised Traffic Flow on Urban Road Networks based on Chaos Theory is presented in this paper. Nonlinear time series modeling techniques were used for the analysis of the traffic flow prediction with emphasis on the technique of computation of the Largest Lyapunov Exponent to aid in the prediction of traffic flow. The study concludes that algorithms based on the computation of the Lyapunov time seem promising as regards facilitating the control of congestion because of the technique’s effectiveness in predicting the dynamics of complex systems especially traffic flow.

  10. Traffic information computing platform for big data

    International Nuclear Information System (INIS)

    Big data environment create data conditions for improving the quality of traffic information service. The target of this article is to construct a traffic information computing platform for big data environment. Through in-depth analysis the connotation and technology characteristics of big data and traffic information service, a distributed traffic atomic information computing platform architecture is proposed. Under the big data environment, this type of traffic atomic information computing architecture helps to guarantee the traffic safety and efficient operation, more intelligent and personalized traffic information service can be used for the traffic information users

  11. Web application for traffic flow forecasting

    OpenAIRE

    Dubravac, Dragan

    2015-01-01

    Disturbances in traffic on highways usually lead to an increase in traffic flow density or even traffic jams. The main goal of the diploma thesis is to produce an application that will predict traffic flow and traffic jams on any given date and time based on traffic flow in the past. By using an estimated desired speed the traffic information gained from flow counters we can forecast the evolution of traffic jams. The application presents a graph that represents the number of vehicles on a...

  12. Traffic information computing platform for big data

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Zongtao, E-mail: ztduan@chd.edu.cn; Li, Ying, E-mail: ztduan@chd.edu.cn; Zheng, Xibin, E-mail: ztduan@chd.edu.cn; Liu, Yan, E-mail: ztduan@chd.edu.cn; Dai, Jiting, E-mail: ztduan@chd.edu.cn; Kang, Jun, E-mail: ztduan@chd.edu.cn [Chang' an University School of Information Engineering, Xi' an, China and Shaanxi Engineering and Technical Research Center for Road and Traffic Detection, Xi' an (China)

    2014-10-06

    Big data environment create data conditions for improving the quality of traffic information service. The target of this article is to construct a traffic information computing platform for big data environment. Through in-depth analysis the connotation and technology characteristics of big data and traffic information service, a distributed traffic atomic information computing platform architecture is proposed. Under the big data environment, this type of traffic atomic information computing architecture helps to guarantee the traffic safety and efficient operation, more intelligent and personalized traffic information service can be used for the traffic information users.

  13. A Useful Metaheuristic for Dynamic Channel Assignment in Mobile Cellular Systems

    Directory of Open Access Journals (Sweden)

    Deepak Kumar Singh

    2012-09-01

    Full Text Available The prime objective of a Channel Assignment Problem (CAP is to assign appropriate number of required channels to each cell in a way to achieve both efficient frequency spectrum utilization and minimization of interference effects (by satisfying a number of channel reuse constraints. Dynamic Channel Assignment (DCA assigns the channels to the cells dynamically according to traffic demand, and hence, can provide higher capacity (or lower call blocking probability, fidelity and quality of service than the fixed assignment schemes. Channel assignment algorithms are formulated as combinatorial optimization problems and are NP-hard. Devising a DCA, that is practical, efficient, and which can generate high quality assignments, is challenging. Though Metaheuristic Search techniques like Evolutionary Algorithms, Differential Evolution, Particle Swarm Optimization prove effective in the solution of Fixed Channel Assignment (FCA problems but they still require high computational time and therefore may be inefficient for DCA. A number of approaches have been proposed for the solution of DCA problem but the high complexity of these proposed approaches makes them unsuitable/less efficient for practical use. Therefore, this paper presents an effective and efficient Hybrid Discrete Binary Differential Evolution Algorithm (HDB-DE for the solution of DCA Problem

  14. The Physics of Traffic and Regional Development

    CERN Document Server

    Helbing, Dirk

    2013-01-01

    This contribution summarizes and explains various principles from physics which are used for the simulation of traffic flows in large street networks, the modeling of destination, transport mode, and route choice, or the simulation of urban growth and regional development. The methods stem from many-particle physics, from kinetic gas theory, or fluiddynamics. They involve energy and entropy considerations, transfer the law of gravity, apply cellular automata and require methods from evolutionary game theory. In this way, one can determine interaction forces among driver-vehicle units, reproduce breakdowns of traffic including features of synchronized congested flow, or understand changing usage patterns of alternative roads. One can also describe daily activity patterns based on decision models, simulate migration streams, and model urban growth as a particular kind of aggregation process.

  15. Traffic routes and signals for the tonoplast.

    Science.gov (United States)

    Pedrazzini, Emanuela; Komarova, Nataliya Y; Rentsch, Doris; Vitale, Alessandro

    2013-06-01

    Tonoplast, the membrane delimiting plant vacuoles, regulates ion, water and nutrient movement between the cytosol and the vacuolar lumen through the activity of its membrane proteins. Correct traffic of proteins from the endoplasmic reticulum (ER) to the tonoplast requires (i) approval by the ER quality control, (ii) motifs for exit from the ER and (iii) motifs that promote sorting to the tonoplast. Recent evidence suggests that this traffic follows different pathways that are protein-specific and could also reflect vacuole specialization for lytic or storage function. The routes can be distinguished based on their sensitivity to drugs such as brefeldin A and C834 as well as using mutant plants that are defective in adaptor proteins of vesicle coats, or dominant-negative mutants of Rab GTPases.

  16. CQ Switch Analysis under Traffic Overload

    Directory of Open Access Journals (Sweden)

    I. Maljević

    2011-06-01

    Full Text Available An analysis of 2x2 crossbar packet switch with buffers at crosspoints and round robin scheduling algorithm is presented in this paper. The analysis is performed for a non-admissible traffic pattern, where output ports are overloaded. The case of full offered load is observed and output ports are loaded with packets that have different arrival probabilities. In addition to the parameters that are commonly observed in such an analysis (throughput and average packet delay, memory requirements for the implementation of the buffer, as well as fair representation when servicing the buffer - the so-called fairness are also analyzed. The results show that even for a switch with a small number of ports very large buffers should be implemented, if we want to achieve satisfactory performance under traffic overload.

  17. A COMPACT MODEL FOR PREDICTING ROAD TRAFFIC NOISE

    Directory of Open Access Journals (Sweden)

    R. Golmohammadi ، M. Abbaspour ، P. Nassiri ، H. Mahjub

    2009-07-01

    Full Text Available Noise is one of the most important sources of pollution in the metropolitan areas. The recognition of road traffic noise as one of the main sources of environmental pollution has led to develop models that enable us to predict noise level from fundamental variables. Traffic noise prediction models are required as aids in the design of roads and sometimes in the assessment of existing, or envisaged changes in, traffic noise conditions. The purpose of this study was to design a prediction road traffic noise model from traffic variables and conditions of transportation in Iran.This paper is the result of a research conducted in the city of Hamadan with the ultimate objective of setting up a traffic noise model based on the traffic conditions of Iranian cities. Noise levels and other variables have been measured in 282 samples to develop a statistical regression model based on A-weighted equivalent noise level for Iranian road condition. The results revealed that the average LAeq in all stations was 69.04± 4.25 dB(A, the average speed of vehicles was 44.57±11.46 km/h and average traffic load was 1231.9 ± 910.2 V/h.The developed model has seven explanatory entrance variables in order to achieve a high regression coefficient (R2=0.901. Comparing means of predicted and measuring equivalent sound pressure level (LAeq showed small difference less than -0.42 dB(A and -0.77 dB(A for Tehran and Hamadan cities, respectively. The suggested road traffic noise model can be effectively used as a decision support tool for predicting equivalent sound pressure level index in the cities of Iran.

  18. KINEMATIC WAVE PROPERTIES OF ANISOTROPIC DYNAMICS MODEL FOR TRAFFIC FLOW

    Institute of Scientific and Technical Information of China (English)

    姜锐; 吴清松; 朱祚金

    2002-01-01

    The analyses of kinematic wave properties of a new dynamics model for traffic flow are carried out. The model does not exhibit the problem that one characteristic speed is always greater than macroscopic traffic speed, and therefore satisfies the requirement that traffic flow is anisotropic. Linear stability analysis shows that the model is stable under certain condition and the condition is obtained. The analyses also indicate that the model has a hierarchy of first-and second-order waves, and allows the existence of both smooth traveling wave and shock wave. However, the model has a distinctive criterion of shock wave compared with other dynamics models, and the distinction makes the model more realistic in dealing with some traffic problems such as wrong-way travel analysis.

  19. Framework for Traffic Congestion Management

    Directory of Open Access Journals (Sweden)

    Mahmud Hassan TALUKDAR

    2013-06-01

    Full Text Available Traffic Congestion is one of many serious global problems in all great cities resulted from rapid urbanization which always exert negative externalities upon society. The solution of traffic congestion is highly geocentric and due to its heterogeneous nature, curbing congestion is one of the hard tasks for transport planners. It is not possible to suggest unique traffic congestion management framework which could be absolutely applied for every great cities. Conversely, it is quite feasible to develop a framework which could be used with or without minor adjustment to deal with congestion problem. So, the main aim of this paper is to prepare a traffic congestion mitigation framework which will be useful for urban planners, transport planners, civil engineers, transport policy makers, congestion management researchers who are directly or indirectly involved or willing to involve in the task of traffic congestion management. Literature review is the main source of information of this study. In this paper, firstly, traffic congestion is defined on the theoretical point of view and then the causes of traffic congestion are briefly described. After describing the causes, common management measures, using world- wide, are described and framework for supply side and demand side congestion management measures are prepared.

  20. Traffic Based Optimization of Spectrum Sensing in Cognitive Radio Networks

    OpenAIRE

    Changhua Yao; Qihui Wu; Linfang Zhou

    2014-01-01

    We propose a more practical spectrum sensing optimization problem in cognitive radio networks (CRN), by considering the data traffic of second user (SU). Compared with most existing work, we do not assume that SU always has packets to transmit; instead, we use the actual data transmitted per second rather than the channel capacity as the achievable throughput, to reformulate the Sensing-Throughput Tradeoff problem. We mathematically analyze the problem of optimal sensing time to maximize the ...

  1. Traffic Light Detection at Night

    DEFF Research Database (Denmark)

    Jensen, Morten Bornø; Philipsen, Mark Philip; Bahnsen, Chris;

    2015-01-01

    Traffic light recognition (TLR) is an integral part of any in- telligent vehicle, it must function both at day and at night. However, the majority of TLR research is focused on day-time scenarios. In this paper we will focus on detection of traffic lights at night and evalu- ate the performance...... of three detectors based on heuristic models and one learning-based detector. Evaluation is done on night-time data from the public LISA Traffic Light Dataset. The learning-based detector out- performs the model-based detectors in both precision and recall. The learning-based detector achieves an average...

  2. Transition Characteristic Analysis of Traffic Evolution Process for Urban Traffic Network

    OpenAIRE

    Longfei Wang; Hong Chen; Yang Li

    2014-01-01

    The characterization of the dynamics of traffic states remains fundamental to seeking for the solutions of diverse traffic problems. To gain more insights into traffic dynamics in the temporal domain, this paper explored temporal characteristics and distinct regularity in the traffic evolution process of urban traffic network. We defined traffic state pattern through clustering multidimensional traffic time series using self-organizing maps and construct a pattern transition network model tha...

  3. Real-Time Corrected Traffic Correlation Model for Traffic Flow Forecasting

    OpenAIRE

    Lu, Hua-pu; Sun, Zhi-yuan; Qu, Wen-cong; Wang, Ling

    2015-01-01

    This paper focuses on the problems of short-term traffic flow forecasting. The main goal is to put forward traffic correlation model and real-time correction algorithm for traffic flow forecasting. Traffic correlation model is established based on the temporal-spatial-historical correlation characteristic of traffic big data. In order to simplify the traffic correlation model, this paper presents correction coefficients optimization algorithm. Considering multistate characteristic of traffic ...

  4. Spatiotemporal traffic-flow dependency and short-term traffic forecasting

    OpenAIRE

    Yang Yue; Anthony Gar-On Yeh

    2008-01-01

    Short-term traffic forecasting is playing an increasing role in modern transport management. Although many short-term traffic forecasting methods have been explored, the spatiotemporal dependency of traffic flow, an important characteristic of traffic dynamics that can benefit the forecasting of traffic changes, is often neglected in short-term traffic forecasting. This paper first investigates the spatiotemporal dependency of traffic flow using cross-correlation analysis and then discusses i...

  5. A Two-Stage Fuzzy Logic Control Method of Traffic Signal Based on Traffic Urgency Degree

    OpenAIRE

    Yan Ge

    2014-01-01

    City intersection traffic signal control is an important method to improve the efficiency of road network and alleviate traffic congestion. This paper researches traffic signal fuzzy control method on a single intersection. A two-stage traffic signal control method based on traffic urgency degree is proposed according to two-stage fuzzy inference on single intersection. At the first stage, calculate traffic urgency degree for all red phases using traffic urgency evaluation module and select t...

  6. RFI channels

    Science.gov (United States)

    Mceliece, R. J.

    1980-01-01

    A class of channel models is presented which exhibit varying burst error severity much like channels encountered in practice. An information-theoretic analysis of these channel models is made, and conclusions are drawn that may aid in the design of coded communication systems for realistic noisy channels.

  7. Characteristics of synchronized traffic in mixed traffic flow

    Institute of Scientific and Technical Information of China (English)

    Ning Hong-Xin; Xue Yu

    2012-01-01

    In this paper,the characteristics of synchronized traffic in mixed traffic flow are investigated based on the braking light model.By introducing the energy dissipation and the distribution of slowdown vehicles,the effects of the maximum velocity,the mixing ratio,and the length of vehicles on the synchronized flow are discussed.It is found that the maximum velocity plays a great role in the synchronized flow in mixed traffic.The energy dissipation and the distribution of slowdown vehicles in the synchronized flow region are greatly different from those in free flow and a traffic jamming region.When all of vehicles have the same maximum velocity with Vmax > 15,the mixed traffic significantly displays synchronized flow,which has been demonstrated by the relation between flow rate and occupancy and estimation of the cross-correlation function.Moreover,the energy dissipation in the synchronized flow region does not increase with occupancy.The distribution of slowdown vehicles shows a changeless platform in the synchronized flow region.This is an interesting phenomenon. It helps to deeply understand the synchronized flow and greatly reduce the energy dissipation of traffic flow.

  8. Distributed sampling measurement method of network traffic in high-speed IPv6 networks

    Institute of Scientific and Technical Information of China (English)

    Pan Qiao; Pei Changxing

    2007-01-01

    With the advent of large-scale and high-speed IPv6 network technology, an effective multi-point traffic sampling is becoming a necessity. A distributed multi-point traffic sampling method that provides an accurate and efficient solution to measure IPv6 traffic is proposed. The proposed method is to sample IPv6 traffic based on the analysis of bit randomness of each byte in the packet header. It offers a way to consistently select the same subset of packets at each measurement point, which satisfies the requirement of the distributed multi-point measurement. Finally, using real IPv6 traffic traces, the conclusion that the sampled traffic data have a good uniformity that satisfies the requirement of sampling randomness and can correctly reflect the packet size distribution of full packet trace is proved.

  9. Inferring traffic burstiness by sampling the buffer occupancy

    NARCIS (Netherlands)

    Mandjes, Michel; Meent, van de Remco

    2004-01-01

    Common practice to determine the required bandwidth capacity for a network link is to measure the 5 minute average link load and then add a safety margin to cater for traffic bursts on small time-scales. Because of the substantial measurement effort required to appropriately determine the effect of

  10. Assessment of Traffic Noise Impacts

    DEFF Research Database (Denmark)

    Rich, Jeppe Husted; Nielsen, Otto Anker

    2004-01-01

    the true social benefit of infrastructure plans. The paper presents a noise assessment model for the Copenhagen region, which brings together GIS technology and non-linear hedonic regression models to reveal the implicit costs of traffic noise measured as the marginal percentage loss in property values...... with respect to the decibel traffic noise. The model distinguishes between houses and apartments and shows that the ability to include refined accessibility variables have significant impact on estimated prices.......A steady growth in traffic intensities in most urban areas throughout the world has forced planners and politicians to seriously consider the resulting environmental impact, such as traffic noise, accidents and air pollution. The assessment of such negative factors is needed in order to reveal...

  11. A multiagent urban traffic simulation

    CERN Document Server

    Tranouez, Pierrick; Langlois, Patrice

    2012-01-01

    We built a multiagent simulation of urban traffic to model both ordinary traffic and emergency or crisis mode traffic. This simulation first builds a modeled road network based on detailed geographical information. On this network, the simulation creates two populations of agents: the Transporters and the Mobiles. Transporters embody the roads themselves; they are utilitarian and meant to handle the low level realism of the simulation. Mobile agents embody the vehicles that circulate on the network. They have one or several destinations they try to reach using initially their beliefs of the structure of the network (length of the edges, speed limits, number of lanes etc.). Nonetheless, when confronted to a dynamic, emergent prone environment (other vehicles, unexpectedly closed ways or lanes, traffic jams etc.), the rather reactive agent will activate more cognitive modules to adapt its beliefs, desires and intentions. It may change its destination(s), change the tactics used to reach the destination (favorin...

  12. Automatic Traffic Recorder (ATR) Stations

    Data.gov (United States)

    Department of Homeland Security — The data included in the GIS Traffic Stations Version database have been assimilated from station description files provided by FHWA for Weigh-in-Motion (WIM), and...

  13. 2013 Traffic Safety Culture Index

    Science.gov (United States)

    ... endorse products or manufacturers. ©2014, AAA Foundation for Traffic Safety Introduction In the quarter century from 1988 through 2012, the lives of 1,018,581 men, women, and children have ended violently as the result ...

  14. Hybrid Traffic Management Model for Multi-Protocol Label Switching Network

    OpenAIRE

    E.R. Naganathan; Rajagopalan, S.

    2011-01-01

    Problem statement: MPLS is a highly scalable, protocol agnostic and data-carrying mechanism. Traffic engineering is the major research area in MPLS due to the emerging requirements of MPLS and the internet usage. A major objective of traffic engineering is to minimize or eliminate high-loss situations. Another goal of traffic engineering is to balance the Quality of Service (QoS) against the cost of operating and maintaining the network. Approach: This study proposes a hybrid model for effect...

  15. Minimizing the Disruptive Effects of Prospective Memory in Simulated Air Traffic Control

    OpenAIRE

    Loft, Shayne; Smith, Rebekah E.; Remington, Roger

    2013-01-01

    Prospective memory refers to remembering to perform an intended action in the future. Failures of prospective memory can occur in air traffic control. In two experiments, we examined the utility of external aids for facilitating air traffic management in a simulated air traffic control task with prospective memory requirements. Participants accepted and handed-off aircraft and detected aircraft conflicts. The prospective memory task involved remembering to deviate from a routine operating pro...

  16. Intelligent Testing of Traffic Light Programs: Validation in Smart Mobility Scenarios

    OpenAIRE

    Javier Ferrer; José García-Nieto; Enrique Alba; Francisco Chicano

    2016-01-01

    In smart cities, the use of intelligent automatic techniques to find efficient cycle programs of traffic lights is becoming an innovative front for traffic flow management. However, this automatic programming of traffic lights requires a validation process of the generated solutions, since they can affect the mobility (and security) of millions of citizens. In this paper, we propose a validation strategy based on genetic algorithms and feature models for the automatic generation of different ...

  17. Lagrangian Multi-Class Traffic State Estimation

    NARCIS (Netherlands)

    Yuan, Y.

    2013-01-01

    Road traffic is important to everybody in the world. People travel and commute everyday. For those who travel by cars (or other types of road vehicles), traffic congestion is a daily experience. One essential goal of traffic researchers is to reduce traffic congestion and to improve the whole traffi

  18. 36 CFR 4.13 - Obstructing traffic.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Obstructing traffic. 4.13... VEHICLES AND TRAFFIC SAFETY § 4.13 Obstructing traffic. The following are prohibited: (a) Stopping or... interfere with the normal flow of traffic....

  19. Study on Macro-traffic Model

    Institute of Scientific and Technical Information of China (English)

    FangGe; GuowuZhang; BaojunYuan; KepingLi

    2004-01-01

    Macro-traffic model is an effective tool for supporting traffic programmer to This article is based on the software products VISEM (demand model) and VISUM (supply model) from PTV Company of Germany, and studies macro-traffic model on the basis of considering that traffic system is an interactive system of between a supply system and a demand system.

  20. Assessing Vessel Traffic Service Operator Situation Awareness

    NARCIS (Netherlands)

    Wiersma, J.W.F.

    2010-01-01

    This thesis describes my study of situation awareness assessment of Vessel Traffic Service (VTS) operators. VTS operators are the traffic controllers on the water. They are responsible for a safe and efficient handling of vessel traffic. They monitor traffic, provide information on request and coord

  1. Internet Load and Traffic Balancing

    Institute of Scientific and Technical Information of China (English)

    李文正; 郭巧; 郭为民

    2005-01-01

    Load and traffic balancing for the Internet are analyzed. An intelligent domain name system(DNS) policy for the control and management of content distribution networks (CDN) is presented. An CDNs network based Urtitech IntelliDNS is built, and performance of the network in realizing traffic and load balancing is measured. It is proved that CDNs provide a valuable service and the methods are feasible.

  2. Stochastic control of traffic patterns

    DEFF Research Database (Denmark)

    Gaididei, Yuri B.; Gorria, Carlos; Berkemer, Rainer;

    2013-01-01

    A stochastic modulation of the safety distance can reduce traffic jams. It is found that the effect of random modulation on congestive flow formation depends on the spatial correlation of the noise. Jam creation is suppressed for highly correlated noise. The results demonstrate the advantage...... of heterogeneous performance of the drivers in time as well as individually. This opens the possibility for the construction of technical tools to control traffic jam formation....

  3. Future Emissions from Railway Traffic

    DEFF Research Database (Denmark)

    Sorenson, Spencer C.

    1998-01-01

    In investigation of the expected development in factors which influence railway energy consumption and emissions. Traffic factors such as train speed, load, an occupancy were considered. Tehcnical factors such an emissions factors, fleet composition and train weight were also considered. An estim......In investigation of the expected development in factors which influence railway energy consumption and emissions. Traffic factors such as train speed, load, an occupancy were considered. Tehcnical factors such an emissions factors, fleet composition and train weight were also considered...

  4. Reports on internet traffic statistics

    OpenAIRE

    Hoogesteger, Martijn; Oliveira Schmidt, de, Ricardo; Sperotto, Anna; Pras, Aiko

    2013-01-01

    Internet traffic statistics can provide valuable information to network analysts and researchers about the way nowadays networks are used. In the past, such information was provided by Internet2 in a public website called Internet2 NetFlow: Weekly Reports. The website reported traffic statistics from the Abilene network on a weekly basis. At that time, the network connected 230 research institutes with a 10Gb/s link. Although these reports were limited to the behavior of the Albeline's users,...

  5. Estimating emissions from railway traffic

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, M.W.; Sorenson, C.

    1997-07-01

    The report discusses methods that can be used to estimate the emissions from various kinds of railway traffic. The methods are based on the estimation of the energy consumption of the train, so that comparisons can be made between electric and diesel driven trains. Typical values are given for the necessary traffic parameters, emission factors, and train loading. Detailed models for train energy consumption are presented, as well as empirically based methods using average train speed and distance between stop. (au)

  6. Characterization and Modeling of Network Traffic

    DEFF Research Database (Denmark)

    Shawky, Ahmed; Bergheim, Hans; Ragnarsson, Olafur;

    2011-01-01

    This paper attempts to characterize and model backbone network traffic, using a small number of statistics. In order to reduce cost and processing power associated with traffic analysis. The parameters affecting the behaviour of network traffic are investigated and the choice is that inter......-arrival time, IP addresses, port numbers and transport protocol are the only necessary parameters to model network traffic behaviour. In order to recreate this behaviour, a complex model is needed which is able to recreate traffic behaviour based on a set of statistics calculated from the parameters values....... The model investigates the traffic generation mechanisms, and grouping traffic into flows and applications....

  7. An Open-Source Microscopic Traffic Simulator

    CERN Document Server

    Treiber, Martin; 10.1109/MITS.2010.939208

    2010-01-01

    We present the interactive Java-based open-source traffic simulator available at www.traffic-simulation.de. In contrast to most closed-source commercial simulators, the focus is on investigating fundamental issues of traffic dynamics rather than simulating specific road networks. This includes testing theories for the spatiotemporal evolution of traffic jams, comparing and testing different microscopic traffic models, modeling the effects of driving styles and traffic rules on the efficiency and stability of traffic flow, and investigating novel ITS technologies such as adaptive cruise control, inter-vehicle and vehicle-infrastructure communication.

  8. Fastlane: Traffic flow modeling and multi-class dynamic traffic management

    NARCIS (Netherlands)

    Schreiter, T.; Van Wageningen-Kessels, F.L.M.; Yuan, Y.; Van Lint, J.W.C.; Hoogendoorn, S.P.

    2012-01-01

    Dynamic Traffic Management (DTM) aims to improve traffic conditions. DTM usually consists of two steps: first the current traffic is estimated, then appropriate control actions are determined based on that estimate. In order to estimate and control the traffic, a suitable traffic flow model that rep

  9. Quasi-dynamic traffic assignment: static traffic assignment with queueing and spillback

    NARCIS (Netherlands)

    Bliemer, M.C.J.; Brederode, L.; Wismans, L.J.J.; Smits, E.S.

    2012-01-01

    Historical traffic patterns can be used for the prediction of traffic flows, as input for macroscopic traffic models, for the imputation of missing or erroneous data and as a basis for traffic management scenarios. This paper investigates the determination of historical traffic patterns by means of

  10. Interaction of Airspace Partitions and Traffic Flow Management Delay

    Science.gov (United States)

    Palopo, Kee; Chatterji, Gano B.; Lee, Hak-Tae

    2010-01-01

    To ensure that air traffic demand does not exceed airport and airspace capacities, traffic management restrictions, such as delaying aircraft on the ground, assigning them different routes and metering them in the airspace, are implemented. To reduce the delays resulting from these restrictions, revising the partitioning of airspace has been proposed to distribute capacity to yield a more efficient airspace configuration. The capacity of an airspace partition, commonly referred to as a sector, is limited by the number of flights that an air traffic controller can safely manage within the sector. Where viable, re-partitioning of the airspace distributes the flights over more efficient sectors and reduces individual sector demand. This increases the overall airspace efficiency, but requires additional resources in some sectors in terms of controllers and equipment, which is undesirable. This study examines the tradeoff of the number of sectors designed for a specified amount of traffic in a clear-weather day and the delays needed for accommodating the traffic demand. Results show that most of the delays are caused by airport arrival and departure capacity constraints. Some delays caused by airspace capacity constraints can be eliminated by re-partitioning the airspace. Analyses show that about 360 high-altitude sectors, which are approximately today s operational number of sectors of 373, are adequate for delays to be driven solely by airport capacity constraints for the current daily air traffic demand. For a marginal increase of 15 seconds of average delay, the number of sectors can be reduced to 283. In addition, simulations of traffic growths of 15% and 20% with forecasted airport capacities in the years 2018 and 2025 show that delays will continue to be governed by airport capacities. In clear-weather days, for small increases in traffic demand, increasing sector capacities will have almost no effect on delays.

  11. Data reduction in modeled packet traffic

    OpenAIRE

    Mehrabian, Maryam

    2012-01-01

        Within Ericsson there is a continuous activity of traffic modeling. Traffic modeling is a practice to analyze traffic patterns and determine necessary resources to handle it optimally. This activity focuses on gathering and analyzing live network measurements, implementing and presenting traffic models. One example of concept in packet traffic modeling is transmission object log which is an aggregation of packet data traces from a measured network over a transmission period. These trace l...

  12. Economic Evaluation of Road Traffic Safety Measures

    OpenAIRE

    Gul, Ejaz

    2013-01-01

    The number of road traffic casualties is still very lofty and the trend shows a boost with each passing day. The road traffic accidents involve fatalities due to which economic resources are damaged and the productivity of the economy is correspondingly impaired. Costs resulting from traffic accidents represent the largest single part of the overall cost of traffic to the economy. Knowledge about the harm of these traffic accidents to the economy is essential if measures to reduce road traffi...

  13. Economic Efficacy of Road Traffic Safety Measures

    OpenAIRE

    Gul, Ejaz

    2013-01-01

    The number of road traffic casualties is still very lofty and the trend shows a boost with each passing day. The road traffic accidents involve fatalities due to which economic resources are damaged and the productivity of the economy is correspondingly impaired. Costs resulting from traffic accidents represent the largest single part of the overall cost of traffic to the economy. Knowledge about the harm of these traffic accidents to the economy is essential if measures to reduce road traffi...

  14. Traffic Signal Using Smart Agent System

    OpenAIRE

    Cheonshik Kim; You S. Hong

    2008-01-01

    In this research, we propose an electro-sensitive traffic light using the smart agent algorithm to reduce traffic congestion and traffic accidents. The multi-agent system approach can provide a new and preferable solution. The proposed method adaptively controls the cycle of traffic signals even though the traffic volume varies. Consequently, we reduce the car waiting time and start-up delay time using fuzzy control of feedback data. In particular, we have designed and implemented a system to...

  15. Functional Apical Large Conductance, Ca2+-activated, and Voltage-dependent K+ Channels Are Required for Maintenance of Airway Surface Liquid Volume*

    OpenAIRE

    Manzanares, Dahis; Gonzalez, Carlos; Ivonnet, Pedro; Chen, Ren-Shiang; Valencia-Gattas, Monica; Gregory E. Conner; Larsson, H. Peter; Salathe, Matthias

    2011-01-01

    Large conductance, Ca2+-activated, and voltage-dependent K+ (BK) channels control a variety of physiological processes in nervous, muscular, and renal epithelial tissues. In bronchial airway epithelia, extracellular ATP-mediated, apical increases in intracellular Ca2+ are important signals for ion movement through the apical membrane and regulation of water secretion. Although other, mainly basolaterally expressed K+ channels are recognized as modulators of ion transport in airway epithelial ...

  16. Boosting of synaptic potentials and spine Ca transients by the peptide toxin SNX-482 requires alpha-1E-encoded voltage-gated Ca channels.

    Directory of Open Access Journals (Sweden)

    Andrew J Giessel

    Full Text Available The majority of glutamatergic synapses formed onto principal neurons of the mammalian central nervous system are associated with dendritic spines. Spines are tiny protuberances that house the proteins that mediate the response of the postsynaptic cell to the presynaptic release of glutamate. Postsynaptic signals are regulated by an ion channel signaling cascade that is active in individual dendritic spines and involves voltage-gated calcium (Ca channels, small conductance (SK-type Ca-activated potassium channels, and NMDA-type glutamate receptors. Pharmacological studies using the toxin SNX-482 indicated that the voltage-gated Ca channels that signal within spines to open SK channels belong to the class Ca(V2.3, which is encoded by the Alpha-1E pore-forming subunit. In order to specifically test this conclusion, we examined the effects of SNX-482 on synaptic signals in acute hippocampal slices from knock-out mice lacking the Alpha-1E gene. We find that in these mice, application of SNX-482 has no effect on glutamate-uncaging evoked synaptic potentials and Ca influx, indicating that that SNX-482 indeed acts via the Alpha-1E-encoded Ca(V2.3 channel.

  17. Urban Traffic Control Using Adjusted Reinforcement Learning in a Multi-agent System

    Directory of Open Access Journals (Sweden)

    Mahshid Helali Moghadam

    2013-09-01

    Full Text Available Dynamism, continuous changes of states and the necessity to respond quickly are the specific characteristics of the environment in a traffic control system. Proposing an appropriate and flexible strategy to meet the existing requirements is always an important issue in traffic control. This study presents an adaptive approach to control urban traffic using multi-agent systems and a reinforcement learning augmented by an adjusting pre-learning stage. In this approach, the agent primarily uses some statistical traffic data and then uses traffic engineering theories for computing appropriate values of the traffic parameters. Having these primary values, the agents start the reinforcement learning based on the basic calculated information. The proposed approach, at first finds the approximate optimal zone for traffic parameters based on traffic engineering theories. Then using an appropriate reinforcement learning, it tries to exploit the best point according to different conditions. This approach was implemented on a network in traffic simulator software. The network was composed of six four phased intersections and 17 two lane streets. In the simulation, pedestrians were not considered in the system. The load of the network is defined in terms of Origin-Destination matrices whose entries represent the number of trips from an origin to a destination as a function of time. The simulation ran for five hours and an average traffic volume was used. According to the simulation results, the proposed approach behaved adaptively in different conditions and had better performance than the theory-based fixed-time control.

  18. BLIND CHANNEL ESTIMATION IN DELAY DIVERSITY FOR FREQUENCY SELECTIVE CHANNELS

    Institute of Scientific and Technical Information of China (English)

    Zhao Zheng; Jia Ying; Yin Qinye

    2003-01-01

    Delay diversity is an effective transmit diversity technique to combat adverse ef-fects of fading. Thus far, previous work in delay diversity assumed that perfect estimates ofcurrent channel fading conditions are available at the receiver and training symbols are requiredto estimate the channel from the transmitter to the receiver. However, increasing the number ofthe antennas increases the required training interval and reduces the available time within whichdata may be transmitted. Learning the channel coefficients becomes increasingly difficult for thefrequency selective channels. In this paper, with the subspace method and the delay character ofdelay diversity, a channel estimation method is proposed, which does not use training symbols. Itaddresses the transmit diversity for a frequency selective channel from a single carrier perspectivein the form of a simple equivalent fiat fading model. Monte Carlo simulations give the perfor-mance of channel estimation and the performance comparison of our channel-estimation-baseddetector with decision feedback equalization, which uses the perfect channel information.

  19. DTALite: A queue-based mesoscopic traffic simulator for fast model evaluation and calibration

    Directory of Open Access Journals (Sweden)

    Xuesong Zhou

    2014-12-01

    Full Text Available A number of emerging dynamic traffic analysis applications, such as regional or statewide traffic assignment, require a theoretically rigorous and computationally efficient model to describe the propagation and dissipation of system congestion with bottleneck capacity constraints. An open-source light-weight dynamic traffic assignment (DTA package, namely DTALite, has been developed to allow a rapid utilization of advanced dynamic traffic analysis capabilities. This paper describes its three major modeling components: (1 a light-weight dynamic network loading simulator that embeds Newell’s simplified kinematic wave model; (2 a mesoscopic agent-based DTA procedure to incorporate driver’s heterogeneity; and (3 an integrated traffic assignment and origin–destination demand calibration system that can iteratively adjust path flow volume and distribution to match the observed traffic counts. A number of real-world test cases are described to demonstrate the effectiveness and performance of the proposed models under different network and data availability conditions.

  20. Air traffic generation for new terminal area air traffic management concepts design and evaluation

    OpenAIRE

    Besada Portas, Juan Alberto; Marquinez Prado, Iñigo; Portillo Garcia, Javier Ignacio; Miguel Vela, Gonzalo de; Bernardos Barbolla, Ana M.

    2015-01-01

    This paper describes two systems that can be used to obtain realistic random traffic samples in a terminal area: a real traffic analyser and a synthetic traffic generator. These two systems allow the air traffic management (ATM) engineer to gain insight on the traffic structure of the area under analysis, and allow obtaining realistic traffic samples enabling the evaluation of new operational concepts, the validation or system performance measurement after procedure changes, the analysis of A...

  1. Percolation properties in a traffic model

    Science.gov (United States)

    Wang, Feilong; Li, Daqing; Xu, Xiaoyun; Wu, Ruoqian; Havlin, Shlomo

    2015-11-01

    As a dynamical complex system, traffic is characterized by a transition from free flow to congestions, which is mostly studied in highways. However, despite its importance in developing congestion mitigation strategies, the understanding of this common traffic phenomenon in a city scale is still missing. An open question is how the traffic in the network collapses from a global efficient traffic to isolated local flows in small clusters, i.e. the question of traffic percolation. Here we study the traffic percolation properties on a lattice by simulation of an agent-based model for traffic. A critical traffic volume in this model distinguishes the free state from the congested state of traffic. Our results show that the threshold of traffic percolation decreases with increasing traffic volume and reaches a minimum value at the critical traffic volume. We show that this minimal threshold is the result of longest spatial correlation between traffic flows at the critical traffic volume. These findings may help to develop congestion mitigation strategies in a network view.

  2. Percolation properties in a traffic model

    CERN Document Server

    Wang, Feilong; Xu, Xiaoyun; Wu, Ruoqian; Havlin, Shlomo

    2015-01-01

    As a dynamical complex system, traffic is characterized by a transition from free flow to congestions, which is mostly studied in highways. However, despite its importance in developing congestion mitigation strategies, the understanding of this common traffic phenomenon in a city-scale is still missing. An open question is how the traffic in the network collapses from a global efficient traffic to isolated local flows in small clusters, i.e. the question of traffic percolation. Here we study the traffic percolation properties on a lattice by simulation of an agent-based model for traffic. A critical traffic volume in this model distinguishes the free-state from congested state of traffic. Our results show that the threshold of traffic percolation decreases with increasing traffic volume and reaches a minimum value at the critical traffic volume. We show that this minimal threshold is the result of longest spatial correlation between traffic flows at the critical traffic volume. These findings may help to dev...

  3. Evaluation of 'user-oriented' and 'black-box' traffic models for link provisioning

    NARCIS (Netherlands)

    R. van de Meent; M.R.H. Mandjes

    2005-01-01

    To offer users a sufficient performance level, network links should be properly provisioned. The required bandwidth capacity may be determined through the use of a model of the real network traffic. In this paper, we study the use of two classes of traffic models: (i) 'user-oriented models', which c

  4. 14 CFR 91.221 - Traffic alert and collision avoidance system equipment and use.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Traffic alert and collision avoidance... RULES Equipment, Instrument, and Certificate Requirements § 91.221 Traffic alert and collision avoidance... collision avoidance system installed in a U.S.-registered civil aircraft must be approved by...

  5. Distributed Air Traffic Control Simulator

    Directory of Open Access Journals (Sweden)

    R. Radovanović

    2013-06-01

    Full Text Available During initial training air traffic control students acquire theoretical knowledge in various fields including air traffic management, aircraft performance, air traffic control equipment and systems, navigation and others. This paper proposes a simulator and explains its use and features that allows students to gain a practical insight into their coursework in order to complement their training. The goal of the simulator is to realistically implement all the key functionalities needed to cover the topics that were presented in class. The simulator offers a user friendly, distributed, and multi-role environment that can be deployed on regular PCs. Moreover, this paper discusses and resolves some of the main conceptual and implementational issues that were faced during simulator development.

  6. On vehicular traffic data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Brics, Martins; Mahnke, Reinhard [Institute of Physics, Rostock University (Germany)

    2011-07-01

    This contribution consists of analysis of empirical vehicular traffic flow data. The main focus lies on the Next Generation Simulation (NGSIM) data. The first findings show that there are artificial structures within the data due to errors of monitoring as well as smoothing position measurement data. As a result speed data show discretisation in 5 feet per second. The aim of this investigation is to construct microscopic traffic flow models which are in agreement to the analysed empirical data. The ongoing work follows the subject of research summarized by Christof Liebe in his PhD thesis entitled ''Physics of traffic flow: Empirical data and dynamical models'' (Rostock, 2010).

  7. ATP hydrolysis is critically required for function of CaV1.3 channels in cochlear inner hair cells via fueling Ca2+ clearance.

    Science.gov (United States)

    Weiler, Simon; Krinner, Stefanie; Wong, Aaron B; Moser, Tobias; Pangršič, Tina

    2014-05-14

    Sound encoding is mediated by Ca(2+) influx-evoked release of glutamate at the ribbon synapse of inner hair cells. Here we studied the role of ATP in this process focusing on Ca(2+) current through CaV1.3 channels and Ca(2+) homeostasis in mouse inner hair cells. Patch-clamp recordings and Ca(2+) imaging demonstrate that hydrolyzable ATP is essential to maintain synaptic Ca(2+) influx in inner hair cells via fueling Ca(2+)-ATPases to avoid an increase in cytosolic [Ca(2+)] and subsequent Ca(2+)/calmodulin-dependent inactivation of CaV1.3 channels.

  8. Traffic Signal Using Smart Agent System

    Directory of Open Access Journals (Sweden)

    Cheonshik Kim

    2008-01-01

    Full Text Available In this research, we propose an electro-sensitive traffic light using the smart agent algorithm to reduce traffic congestion and traffic accidents. The multi-agent system approach can provide a new and preferable solution. The proposed method adaptively controls the cycle of traffic signals even though the traffic volume varies. Consequently, we reduce the car waiting time and start-up delay time using fuzzy control of feedback data. In particular, we have designed and implemented a system to create optimum traffic signals in congested conditions. The effectiveness of this method was shown through simulation of multiple intersections.

  9. Structure Model of Urban Traffic System Evolution

    Institute of Scientific and Technical Information of China (English)

    JIANG Ke-jin; ZHANG Dian-ye

    2008-01-01

    A structure model of urban traffic system evolution is built based on the analysis of the factors influencing the system evolution and the hierarchy between the factors. Then the influencing degrees of the factors are quantificationally analyzed by DEMATE (decision making trial and evaluation laboratory). The analysis results indicate that the traffic mode structure which achieves the highest central degree is the dominant influencing factor of the urban traffic system evolution, and that economy development and the traffic poficy axe the second important factors that also affect the traffic mode structures. Furthermore, physical geography is a basic restriction to the urban traffic system evolution.

  10. Traffic-Sign Recognition Systems

    CERN Document Server

    Escalera, Sergio

    2011-01-01

    This work presents a full generic approach to the detection and recognition of traffic signs. The approach is based on the latest computer vision methods for object detection, and on powerful methods for multiclass classification. The challenge was to robustly detect a set of different sign classes in real time, and to classify each detected sign into a large, extensible set of classes. To address this challenge, several state-of-the-art methods were developed that can be used for different recognition problems. Following an introduction to the problems of traffic sign detection and categoriza

  11. Agent Based Individual Traffic guidance

    DEFF Research Database (Denmark)

    Wanscher, Jørgen Bundgaard

    2004-01-01

    can be obtained through cellular phone tracking or GPS systems. This information can then be used to provide individual traffic guidance as opposed to the mass information systems of today -- dynamic roadsigns and trafficradio. The goal is to achieve better usage of road and time. The main topic......When working with traffic planning or guidance it is common practice to view the vehicles as a combined mass. >From this models are employed to specify the vehicle supply and demand for each region. As the models are complex and the calculations are equally demanding the regions and the detail...

  12. Traffic Flow Management and Optimization

    Science.gov (United States)

    Rios, Joseph Lucio

    2014-01-01

    This talk will present an overview of Traffic Flow Management (TFM) research at NASA Ames Research Center. Dr. Rios will focus on his work developing a large-scale, parallel approach to solving traffic flow management problems in the national airspace. In support of this talk, Dr. Rios will provide some background on operational aspects of TFM as well a discussion of some of the tools needed to perform such work including a high-fidelity airspace simulator. Current, on-going research related to TFM data services in the national airspace system and general aviation will also be presented.

  13. Traffic and Granular Flow '11

    CERN Document Server

    Buslaev, Alexander; Bugaev, Alexander; Yashina, Marina; Schadschneider, Andreas; Schreckenberg, Michael; TGF11

    2013-01-01

    This book continues the biannual series of conference proceedings, which has become a classical reference resource in traffic and granular research alike. It addresses new developments at the interface between physics, engineering and computational science. Complex systems, where many simple agents, be they vehicles or particles, give rise to surprising and fascinating phenomena.   The contributions collected in these proceedings cover several research fields, all of which deal with transport. Topics include highway, pedestrian and internet traffic, granular matter, biological transport, transport networks, data acquisition, data analysis and technological applications. Different perspectives, i.e. modeling, simulations, experiments and phenomenological observations, are considered.

  14. Effects of traffic infrastructure and road design on safe driving

    NARCIS (Netherlands)

    Horst, A.R.A. van der

    2014-01-01

    One of the building blocks of the Dutch success in road safety is the Sustainable Safety approach. This philosophy specifies that road safety should be a design requirement in road traffic with a focus on the use of human characteristics as a starting point, considering both humans’ physical vulnera

  15. Dynamic one-way traffic control in automated transportation systems

    NARCIS (Netherlands)

    Ebben, M; van der Zee, DJ

    2004-01-01

    In a project on underground freight transportation using Automated Guided Vehicles, single lanes for traffic in two directions are constructed to reduce infrastructure investment. Intelligent control rules are required to manage vehicle flows such, that collision is avoided and waiting times are min

  16. Trunk Reservation in Multi-service Networks with BPP Traffic

    DEFF Research Database (Denmark)

    Zheng, H.; Zhang, Qi; Iversen, Villy Bæk

    2006-01-01

    algorithm which allows for calculation of individual performance measures for each service, in particular the traffic congestion. The algorithm is numerically robust and requires a minimum of computer memory and computing time. The approximation is good when the services have equal mean service times....

  17. Aberrant over-expression of TRPM7 ion channels in pancreatic cancer: required for cancer cell invasion and implicated in tumor growth and metastasis

    Directory of Open Access Journals (Sweden)

    Nelson S. Yee

    2015-03-01

    Full Text Available Our previous studies in zebrafish development have led to identification of the novel roles of the transient receptor potential melastatin-subfamily member 7 (TRPM7 ion channels in human pancreatic cancer. However, the biological significance of TRPM7 channels in pancreatic neoplasms was mostly unexplored. In this study, we determined the expression levels of TRPM7 in pancreatic tissue microarrays and correlated these measurements in pancreatic adenocarcinoma with the clinicopathological features. We also investigated the role of TRPM7 channels in pancreatic cancer cell invasion using the MatrigelTM-coated transwell assay. In normal pancreas, TRPM7 is expressed at a discernable level in the ductal cells and centroacinar cells and at a relatively high level in the islet endocrine cells. In chronic pancreatitis, pre-malignant tissues, and malignant neoplasms, there is variable expression of TRPM7. In the majority of pancreatic adenocarcinoma specimens examined, TRPM7 is expressed at either moderate-level or high-level. Anti-TRPM7 immunoreactivity in pancreatic adenocarcinoma significantly correlates with the size and stages of tumors. In human pancreatic adenocarcinoma cells in which TRPM7 is highly expressed, short hairpin RNA-mediated suppression of TRPM7 impairs cell invasion. The results demonstrate that TRPM7 channels are over-expressed in a proportion of the pre-malignant lesions and malignant tumors of the pancreas, and they are necessary for invasion by pancreatic cancer cells. We propose that TRPM7 channels play important roles in development and progression of pancreatic neoplasm, and they may be explored as clinical biomarkers and targets for its prevention and treatment.

  18. Traffic Engineering of Cellular Wireless Communication Systems

    DEFF Research Database (Denmark)

    Iversen, Villy Bæk

    2002-01-01

    In mobile communications an efficient utilisation of the channels is of great importance. In this paper we describe the basic principles for obtaining the maximum utilisation and study strategies for obtaining these limits. In general a high degree of sharing is efficient, but requires service...

  19. Adaptive Resource Allocation and Internet Traffic Engineering on Data Network

    Directory of Open Access Journals (Sweden)

    Hatim Hussein

    2015-02-01

    Full Text Available This research paper describes the issues of bandwid th allocation, optimum capacity allocation, network operational cost reduction, and improve Int ernet user experience. Traffic engineering (TE is used to manipulate network traffic to achie ve certain requirements and meets certain needs. TE becomes one of the most important buildin g blocks in the design of the Internet backbone infrastructure. Research objective: effici ent allocation of bandwidth across multiple paths. Optimum path selection. Minimize network tra ffic delays and maximize bandwidth utilization over multiple network paths. The bandwi dth allocation is performed proportionally over multiple paths based on the path capacity.

  20. Wireless traffic steering for green cellular networks

    CERN Document Server

    Zhang, Shan; Zhou, Sheng; Niu, Zhisheng; Shen, Xuemin (Sherman)

    2016-01-01

    This book introduces wireless traffic steering as a paradigm to realize green communication in multi-tier heterogeneous cellular networks. By matching network resources and dynamic mobile traffic demand, traffic steering helps to reduce on-grid power consumption with on-demand services provided. This book reviews existing solutions from the perspectives of energy consumption reduction and renewable energy harvesting. Specifically, it explains how traffic steering can improve energy efficiency through intelligent traffic-resource matching. Several promising traffic steering approaches for dynamic network planning and renewable energy demand-supply balancing are discussed. This book presents an energy-aware traffic steering method for networks with energy harvesting, which optimizes the traffic allocated to each cell based on the renewable energy status. Renewable energy demand-supply balancing is a key factor in energy dynamics, aimed at enhancing renewable energy sustainability to reduce on-grid energy consum...

  1. Highway and traffic engineering in developing countries

    DEFF Research Database (Denmark)

    1996-01-01

    Describes road and traffic engineering methods and problems in developing countries as opposed to similar problems in industrialized countries......Describes road and traffic engineering methods and problems in developing countries as opposed to similar problems in industrialized countries...

  2. Cubesat Constellation Design for Air Traffic Monitoring

    Science.gov (United States)

    Nag, Sreeja; Rios, Joseph Lucio; Gerhardt, David; Pham, Camvu

    2015-01-01

    Suitably equipped global and local air traffic can be tracked. The tracking information may then be used for control from ground-based stations by receiving the Automatic Dependent Surveillance-Broadcast (ADS-B) signal. The ADS-B signal, emitted from the aircraft's Mode-S transponder, is currently tracked by terrestrial based receivers but not over remote oceans or sparsely populated regions such as Alaska or the Pacific Ocean. Lack of real-time aircraft time/location information in remote areas significantly hinders optimal planning and control because bigger "safety bubbles" (lateral and vertical separation) are required around the aircraft until they reach radar-controlled airspace. Moreover, it presents a search-and-rescue bottleneck. Aircraft in distress, e.g. Air France AF449 that crashed in 2009, take days to be located or cannot be located at all, e.g. Malaysia Airlines MH370 in 2014. In this paper, we describe a tool for designing a constellation of small satellites which demonstrates, through high-fidelity modeling based on simulated air traffic data, the value of space-based ADS-B monitoring and provides recommendations for cost-efficient deployment of a constellation of small satellites to increase safety and situational awareness in the currently poorly-served surveillance area of Alaska. Air traffic data has been obtained from the Future ATM Concepts Evaluation Tool (FACET), developed at NASA Ames Research Center, simulated over the Alaskan airspace over a period of one day. The simulation is driven by MATLAB with satellites propagated and coverage calculated using AGI's Satellite ToolKit(STK10).

  3. Macroscopic models for traffic safety.

    NARCIS (Netherlands)

    Oppe, S.

    1988-01-01

    Recently there has been an increased interest in the application of macroscopic models for the description of developments in traffic safety. A discussion was started on the causes of the sudden decrease in the number of fatal and injury accidents after 1974. Before that time these numbers had incre

  4. Traffic Congestion and Congestion Pricing

    OpenAIRE

    Verhoef, E.T.; Lindsey, C.R.

    2000-01-01

    For several decades growth of traffic volumes has outstrippedinvestments inroad infrastructure. The result has been a relentless increase intrafficcongestion. This paper reviews the economic principles behindcongestionpricing in static and dynamic settings, which derive from thebenefits ofcharging travellers for the externalities they create. Specialattention ispaid to various complications that make simple textbook congestionpricingmodels of limited relevance, and dictate that congestion pri...

  5. Learning to Detect Traffic Signs

    DEFF Research Database (Denmark)

    Møgelmose, Andreas; Trivedi, Mohan M.; Moeslund, Thomas B.

    2012-01-01

    This study compares the performance of sign detection based on synthetic training data to the performance of detection based on real-world training images. Viola-Jones detectors are created for 4 different traffic signs with both synthetic and real data, and varying numbers of training samples...

  6. Multi-Layer Traffic Steering

    DEFF Research Database (Denmark)

    Fotiadis, Panagiotis; Polignano, Michele; Gimenez, Lucas Chavarria;

    2013-01-01

    This paper investigates the potentials of traffic steering in the Radio Resource Control (RRC) Idle state by evaluating the Absolute Priorities (AP) framework in a multilayer Long Term Evolution (LTE) macrocell scenario. Frequency priorities are broadcast on the system information and RRC Idle...

  7. The role of traffic rules.

    NARCIS (Netherlands)

    Noordzij, P.C.

    1988-01-01

    Experienced road users seem to have their own set of traffic rules (including rules about when to violate the official rules). The number of violations is enormous, causing great concern for the authorities. The situation could be improved by separating a set of rules with the aim of deterring road

  8. Improving Experience-Based Admission Control through Traffic Type Awareness

    Directory of Open Access Journals (Sweden)

    Jens Milbrandt

    2007-04-01

    Full Text Available Experience-based admission control (EBAC is a hybrid approach combining the classical parameter-based and measurement-based admission control. EBAC calculates an appropriate overbooking factor used to overbook link capacities with resource reservations in packet-switched networks. This overbooking factor correlates with the average peak-to-mean rate ratio of all admitted traffic flows on the link. So far, a single overbooking factor is calculated for the entire traffic aggregate. In this paper, we propose typespecific EBAC which provides a compound overbooking factor considering different types of traffic that subsume flows with similar peak-to-mean rate ratios. The concept can be well implemented since it does not require measurements of type-specific traffic aggregates. We give a proof of concept for this extension and compare it with the conventional EBAC approach. We show that EBAC with type-specific overbooking leads to better resource utilization under normal conditions and to faster response times for changing traffic mixes.

  9. Simulation of Road Traffic Applying Model-Driven Engineering

    Directory of Open Access Journals (Sweden)

    Alberto FERNÁNDEZ-ISABEL

    2016-05-01

    Full Text Available Road traffic is an important phenomenon in modern societies. The study of its different aspects in the multiple scenarios where it happens is relevant for a huge number of problems. At the same time, its scale and complexity make it hard to study. Traffic simulations can alleviate these difficulties, simplifying the scenarios to consider and controlling their variables. However, their development also presents difficulties. The main ones come from the need to integrate the way of working of researchers and developers from multiple fields. Model-Driven Engineering (MDE addresses these problems using Modelling Languages (MLs and semi-automatic transformations to organise and describe the development, from requirements to code. This paper presents a domain-specific MDE framework for simulations of road traffic. It comprises an extensible ML, support tools, and development guidelines. The ML adopts an agent-based approach, which is focused on the roles of individuals in road traffic and their decision-making. A case study shows the process to model a traffic theory with the ML, and how to specialise that specification for an existing target platform and its simulations. The results are the basis for comparison with related work.

  10. Performance Modeling for Heterogeneous Wireless Networks with Multiservice Overflow Traffic

    DEFF Research Database (Denmark)

    Huang, Qian; Ko, King-Tim; Iversen, Villy Bæk

    2009-01-01

    Performance modeling is important for the purpose of developing efficient dimensioning tools for large complicated networks. But it is difficult to achieve in heterogeneous wireless networks, where different networks have different statistical characteristics in service and traffic models....... Multiservice loss analysis based on multi-dimensional Markov chain becomes intractable in these networks due to intensive computations required. This paper focuses on performance modeling for heterogeneous wireless networks based on a hierarchical overlay infrastructure. A method based on decomposition...... of the correlated traffic is used to achieve an approximate performance modeling for multiservice in hierarchical heterogeneous wireless networks with overflow traffic. The accuracy of the approximate performance obtained by our proposed modeling is verified by simulations....

  11. On the ground truth problem of malicious DNS traffic analysis

    DEFF Research Database (Denmark)

    Stevanovic, Matija; Pedersen, Jens Myrup; D’Alconzo, Alessandro;

    2015-01-01

    DNS is often abused by Internet criminals in order to provide flexible and resilient hosting of malicious content and reliable communication within their network architecture. The majority of detection methods targeting alicious DNS traffic are data-driven, most commonly having machine learning...... of obtaining ground truth by incorporating the operator's insight in efficient and effective manner. We evaluate the proposed approach on a case study based on DNS traffic from an ISP network by comparing it with the popular labeling practices that rely on domain name and IP blacklists and whitelisting...... algorithms at their core. These methods require accurate ground truth of both malicious and benign DNS traffic for model training as well as for the performance evaluation. This paper elaborates on the problem of obtaining such a ground truth and evaluates practices employed by contemporary detection methods...

  12. Fatigue Minimization Work Shift Scheduling for Air Traffic Controllers

    Directory of Open Access Journals (Sweden)

    Ta-Chung Wang

    2013-05-01

    Full Text Available It is common for Air Traffic Controllers to control air traffic during the night and to experience fatigue. Although fatigue is not the direct cause of aviation accidents, 21 percent of accidents are fatigue-related. Therefore countries and companies have tried to regulate work hours to avoid extreme fatigue, thus decreasing human error resulting from fatigue. However, these regulations may not reflect that actual fatigue variation and fatigue levels can be decreased still more by scheduling appropriately. This paper focuses on optimal work shift scheduling to reduce air traffic controller fatigue. First, a mathematical model is established to describe fatigue levels. The objective function is to reduce the fatigue peak produced by work shifts as much as possible. Various constraints, such as holidays and manpower requirements are considered. The optimization problem is then solved using integer programming. We take a sample schedule and draw conclusions by comparing our results with the original fatigue levels.

  13. The Embedding Capacity of Information Flows Under Renewal Traffic

    CERN Document Server

    Marano, Stefano; He, Ting; Tong, Lang

    2011-01-01

    Given two independent point processes and a certain rule for matching points between them, what is the fraction of matched points over infinitely long streams? In many application contexts, e.g., secure networking, a meaningful matching rule is that of a maximum causal delay, and the problem is related to embedding a flow of packets in cover traffic such that no traffic analysis can detect it. We study the best undetectable embedding policy and the corresponding maximum flow rate ---that we call the embedding capacity--- under the assumption that the cover traffic can be modeled as arbitrary renewal processes. We find that computing the embedding capacity requires the inversion of very structured linear systems that, for a broad range of renewal models encountered in practice, admits a fully analytical expression in terms of the renewal function of the processes. Our main theoretical contribution is a simple closed form of such relationship. This result enables us to explore properties of the embedding capaci...

  14. Traffic Engineering And Supporting QoS

    OpenAIRE

    2003-01-01

    ABSTRACT Traffic Engineering describes techniques for optimising network performance by measuring, modelling, characterizing and controlling Internet traffic for specific performance goals [11]. This is a comprehensive definition. Traffic engineering performance goals typically fall into one of two categories. The first one is traffic related performance objectives such as minimizing packet loss, lowering end-to-end delay, or supporting a contracted Service Level Agreement (SLA). The se...

  15. Protection Methods in Traffic Engineering MPLS Networks

    OpenAIRE

    Kimani, Peter

    2013-01-01

    The objective of this project was to perform a theoretical review of Multiprotocol Label Switching (MPLS) Traffic Engineering (TE) technology and traffic protection methods in the Traffic Engineering on MPLS networks and implement traffic protection in an ISP’s (Internet Service Provider’s) network. The project was carried out first by introducing VPN (Virtual Private Network) and its different categories and modes. VPN is closely related to MPLS. The MPLS-TE was introduced and its operat...

  16. Traffic Signals in Motorcycle Dependent Cities

    OpenAIRE

    Do, Quoc Cuong

    2009-01-01

    Traffic signal control was first invented in 1868 in Great Britain. Then, it has quickly spread across many other countries, what are now usually developed countries. Therefore, during a long history of development, traffic signals usually have been dealing with traffic in which four-wheel vehicles play an important role in motorised traffic. However, as a result of an unequal development among countries, many Motorcycle Dependent Cities (MDCs) nowadays still exist mostly in the developing co...

  17. Space-time modeling of traffic flow

    OpenAIRE

    Kamarianakis, Yiannis; Prastacos, Poulicos

    2002-01-01

    A key concern in transportation planning and traffic management is the ability to forecast traffic flows on a street network. Traffic flows forecasts can be transformed to obtain travel time estimates and then use these as input to travel demand models, dynamic route guidance and congestion management procedures. A variety of mathematical techniques have been proposed for modeling traffic flow on a street network. Briefly, the most widely used theories are: -Kinetic models based on partial di...

  18. Vehicle Traffic Congestion Estimation Based on RFID

    OpenAIRE

    Al-Naima, Fawzi M.; Hamd, Hassan A.

    2012-01-01

    Due to the proliferation in the number of vehicles on the road, traffic problems are bound to exist. Therefore, the use of Intelligent Transportation Systems (ITS) has become mandatory for obtaining traffic information from roads. Radio Frequency Identification (RFID) technology has been used to obtain vehicles’ IDs (tag ID) from RFID readers and to collect traffic information in real‐time. This paper proposes a simulation system for the Vehicle Traffic Congestion Estimation (VTCE) based on R...

  19. Poisson vs. Long-Tailed Internet traffic

    OpenAIRE

    2005-01-01

    In this thesis, we reexamine the long discussion on which model is suitable for studying Internet traffic: Poisson or Long-tailed Internet traffic. Poisson model, adapted from telephone network, has been used since the beginning of World Wide Web, while long-tailed distribution gradually takes over with believable evidence. Instead of using Superposition of Point Processes to explain why traffic that is not Poisson tends towards Poisson traffic as the load increases, as it is recent...

  20. Traffic Monitoring Using M2M Communication

    OpenAIRE

    Kumar, Shiu; Ham, Eun Sik; Lee, Seong Ro

    2014-01-01

    This paper presents an intelligent traffic monitoring system using wireless vision sensor network that captures and processes the real-time video image to obtain the traffic flow rate and vehicle speeds along different urban roadways. This system will display the traffic states on the front roadways that can guide the drivers to select the right way and avoid potential traffic congestions. On the other hand, it will also monitor the vehicle speeds and store the vehicle details, for those brea...

  1. Particle hopping models and traffic flow theory

    OpenAIRE

    Nagel, Kai

    1995-01-01

    This paper shows how particle hopping models fit into the context of traffic flow theory. Connections between fluid-dynamical traffic flow models, which derive from the Navier-Stokes-equations, and particle hopping models are shown. In some cases, these connections are exact and have long been established, but have never been viewed in the context of traffic theory. In other cases, critical behavior of traffic jam clusters can be compared to instabilities in the partial differential equations...

  2. Empirical Phase Diagram of Congested Traffic Flow

    OpenAIRE

    Lee, H. Y.; Lee, H. -W.; Kim, D.

    1999-01-01

    We present an empirical phase diagram of the congested traffic flow measured on a highway section with one effective on-ramp. Through the analysis of local density-flow relations and global spatial structure of the congested region, four distinct congested traffic states are identified. These states appear at different levels of the upstream flux and the on-ramp flux, thereby generating a phase digram of the congested traffic flow. Observed traffic states are discussed in connection with rece...

  3. Approaches for Intelligent Traffic System: A Survey

    OpenAIRE

    Pratishtha Gupta; G. N. Purohit; Amrita Dadhich

    2012-01-01

    This survey presents various approaches for intelligent traffic systems. The potential research fields in which Intelligent Traffic System emerges as an important application area are highlighted andvarious issues have been identified which need to be handled while developing such a system for an urban area, where an efficient traffic management has become the need of hour.A model is also proposed capable of managing intelligent traffic system using CCTV cameras and WAN. The proposed model wi...

  4. TRAFFIC SENSITIVE AND TRAFFIC LOAD AWARE PATH SELECTION ALGORITHM FOR MMR WIMAX NETWORKS

    Directory of Open Access Journals (Sweden)

    Sandhya Kulkarni

    2011-08-01

    Full Text Available The recent developments in the broadband wireless access (BWA communication systems haveintroduced several major changes to the existing systems. Legacy IEEE 802.16j is one such amendment tothe existing IEEE 802.16 WiMAX family. The key modification introduced by 802.16j system is theconcept of relay station (RS, which may be used to enhance the system coverage or to make systemthroughput optimal. The end terminals, subscriber stations (SS are unchanged in the standard. Theoverall change pertinent to the system has raised many unresolved issues related to RS and multi-hoprelay base station (MR-BS. The selection of path from a SS to MR-BS via a RS is also one of the issues,need to be addressed. The path selection of a SS in both uplink and downlink directions is left open in thestandard. It is very significant to satisfy the traffics of stringent quality of service (QoS requirements andto appropriately manage the resources of a cell under different circumstances. This paper proposes apath selection algorithm to achieve the aforementioned qualities in the network. The path selectionmetrics include traffic load of the transparent relay station and traffic sensitivity factor of the SS. Anextensive simulation work discusses the performance evaluation of the proposed work using QualNetsimulator.

  5. Road Traffic Accidents in Kazakhstan

    Directory of Open Access Journals (Sweden)

    Alma Aubakirova

    2013-03-01

    Full Text Available Background: The article provides the analysis of death rates in road traffic accidents in Kazakhstan from 2004 to 2010 and explores the use of sanitary aviation.Methods: Data of fatalities caused by road traffic accidents were collected and analysed. Descriptive and analytical methods of epidemiology and biomedical statistics were applied.Results: Totaly 27,003 people died as a result of road traffic accidents in this period. The death rate for the total population due to road traffic accidents was 25.0±2.10/0000. The death rate for men was (38.3±3.20/0000, which was higher (P<0.05 than that for women (12.6±1.10/0000. High death rates in the entire male population were identified among men of 30-39 years old, whereas the highest rates for women were attributed to the groups of 50-59 years old and 70-79 years old. In time dynamics, death rates tended to decrease: the total population (Тdec=−2.4%, men (Тdec=−2.3% and women (Тdec=−1.4%. When researching territorial relevance, the rates were established as low (to 18.30/0000, average (between18.3 and24.00/0000 and high (from 24.00/0000 and above. Thus, the regions with high rates included Akmola region (24.30/0000, Mangistau region (25.90/0000, Zhambyl region (27.30/0000, Almaty region (29.30/0000 and South Kazakhstan region (32.40/0000.Conclusion: The identified epidemiological characteristics of the population deaths rates from road traffic accidents should be used in integrated and targeted interventions to enhance prevention of injuries in accidents.

  6. Traffic fatalities and economic growth.

    Science.gov (United States)

    Kopits, Elizabeth; Cropper, Maureen

    2005-01-01

    This paper examines the relationship between traffic fatality risk and per capita income and uses it to forecast traffic fatalities by geographic region. Equations for the road death rate (fatalities/population) and its components--the rate of motorization (vehicles/population) and fatalities per vehicle (F/V)--are estimated using panel data from 1963 to 1999 for 88 countries. The natural logarithm of F/P, V/P, and F/V are expressed as spline (piecewise linear) functions of the logarithm of real per capita GDP (measured in 1985 international prices). Region-specific time trends during the period 1963-1999 are modeled in linear and log-linear form. These models are used to project traffic fatalities and the stock of motor vehicles to 2020. The per capita income at which traffic fatality risk (fatalities/population) begins to decline is 8600 US dollars (1985 international dollars) when separate time trends are used for each geographic region. This turning point is driven by the rate of decline in fatalities/vehicles as income rises since vehicles/population, while increasing with income at a decreasing rate, never declines with economic growth. Projections of future traffic fatalities suggest that the global road death toll will grow by approximately 66% over the next twenty years. This number, however, reflects divergent rates of change in different parts of the world: a decline in fatalities in high-income countries of approximately 28% versus an increase in fatalities of almost 92% in China and 147% in India. The road death rate is projected to rise to approximately 2 per 10,000 persons in developing countries by 2020, while it will fall to less than 1 per 10,000 in high-income countries.

  7. 30 CFR 56.9100 - Traffic control.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Traffic control. 56.9100 Section 56.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Dumping Traffic Safety § 56.9100 Traffic control. To provide for the safe movement of...

  8. Computational intelligence for traffic and mobility

    CERN Document Server

    Wang, Wuhong

    2012-01-01

    This book presents the new development of computation intelligence for traffic, transportation and mobility, the main contents include traffic safety, mobility analysis, intelligent transportation system, smart vehicle, transportation behavior, driver modeling and assistance, transportation risk analysis and reliability system analysis, vehicle operation and active safety, urban traffic management and planning.

  9. Predicting Information Flows in Network Traffic.

    Science.gov (United States)

    Hinich, Melvin J.; Molyneux, Robert E.

    2003-01-01

    Discusses information flow in networks and predicting network traffic and describes a study that uses time series analysis on a day's worth of Internet log data. Examines nonlinearity and traffic invariants, and suggests that prediction of network traffic may not be possible with current techniques. (Author/LRW)

  10. Empirical analysis of heterogeneous traffic flow

    NARCIS (Netherlands)

    Ambarwati, L.; Pel, A.J.; Verhaeghe, R.J.; Van Arem, B.

    2013-01-01

    Traffic flow in many developing countries is strongly mixed comprising vehicle types, such as motorcycles, cars, (mini) buses, and trucks; furthermore, traffic flow typically exhibits free inter-lane exchanges. This phenomenon causes a complex vehicle interaction, rendering most existing traffic flo

  11. Traffic Flow Models and Their Numerical Solutions

    OpenAIRE

    Jin, Wenlong

    2004-01-01

    In this thesis, Riemann problems and Godunov methods are developed for higher order traffic flow models. A rigorous analysis of the first order traffic flow model of inhomogeneous road is presented. A two-level simulation framework of network vehicular traffic is proposed as a Godunov-type finite difference system with the supply-demand method as an alternative of Riemann solver.

  12. 36 CFR 1004.13 - Obstructing traffic.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Obstructing traffic. 1004.13 Section 1004.13 Parks, Forests, and Public Property PRESIDIO TRUST VEHICLES AND TRAFFIC SAFETY § 1004.13 Obstructing traffic. The following are prohibited: (a) Stopping or parking a vehicle upon a Presidio...

  13. 49 CFR 236.769 - Locking, traffic.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking, traffic. 236.769 Section 236.769... Locking, traffic. Electric locking which prevents the manipulation of levers or other devices for changing the direction of traffic on a section of track while that section is occupied or while a...

  14. 49 CFR 1139.2 - Traffic study.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Traffic study. 1139.2 Section 1139.2... of General Commodities § 1139.2 Traffic study. (a) The respondents shall submit a traffic study for... “base-calendar year—actual.” The study shall include a probability sampling of the actual...

  15. 15 CFR 265.22 - Bicycle traffic.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Bicycle traffic. 265.22 Section 265.22... STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE REGULATIONS GOVERNING TRAFFIC AND CONDUCT REGULATIONS GOVERNING TRAFFIC AND CONDUCT ON THE GROUNDS OF THE NATIONAL INSTITUTE OF STANDARDS &...

  16. Prediction of Railway Passenger Traffic Volume

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The current situation of the railway passenger traffic (RPT) andthe traffic marketing is analyzed. The grey model theory is adopted to establish a prediction model for the railway passenger traffic volume (RPTV). The RPTV from 2001 to 2005 is predicted with the proposed model, and a few suggestions are put forward.

  17. Capturing Internet Traffic Dynamics through Graph Distances

    NARCIS (Netherlands)

    Uhlig, S.; Fu, B.; Jamakovic, A.

    2009-01-01

    Studies of the Internet have typically focused either on the routing system, i.e. the paths chosen to reach a given destination, or on the evolution of traffic on a physical link. In this paper, we combine routing and traffic, and study for the first time the evolution of the traffic on the Internet

  18. ReFlow: Reports on Internet Traffic

    NARCIS (Netherlands)

    Hoogesteger, Martijn; Oliveira Schmidt, de Ricardo; Sperotto, Anna; Pras, Aiko

    2014-01-01

    Internet traffic statistics can provide valuable information to network analysts and researchers about the traffic, technologies and main characteristics of today’s networks. For many years Internet2 maintained a public website with statistics about the traffic in the Abilene network. This site was

  19. Phase diagram distortion from traffic parameter averaging.

    NARCIS (Netherlands)

    Stipdonk, H. Toorenburg, J. van & Postema, M.

    2010-01-01

    Motorway traffic congestion is a major bottleneck for economic growth. Therefore, research of traffic behaviour is carried out in many countries. Although well describing the undersaturated free flow phase as an almost straight line in a (k,q)-phase diagram, congested traffic observations and theori

  20. STAQ: Static Traffic Assignment with Queing

    NARCIS (Netherlands)

    Brederode, L.; Bliemer, M.C.J.; Wismans, L.

    2010-01-01

    Because of computation time issues on large networks, most strategic regional and urban transport models today use static instead of dynamic traffic assignment procedures. Mathematical models of traffic assignment are usually based upon Wardrop’s principle. To solve this static traffic equilibrium p

  1. NEW POSSIBILITIES OF RAILWAY TRAFFIC CONTROL SYSTEMS

    Directory of Open Access Journals (Sweden)

    Lionginas LIUDVINAVIČIUS

    2016-06-01

    Full Text Available This article analyses the train traffic control systems in 1435 mm and 1520 mm gauge railways. The article analyses the aspects of train traffic control and locomotive energy saving by using the coordinates of track profile change that have been received from GPS. In the article, achievements of Lithuanian railways (LG in the area of train traffic control optimisation are presented.

  2. NEW POSSIBILITIES OF RAILWAY TRAFFIC CONTROL SYSTEMS

    OpenAIRE

    Lionginas LIUDVINAVIČIUS; Stasys DAILYDKA; Aleksander SŁADKOWSKI

    2016-01-01

    This article analyses the train traffic control systems in 1435 mm and 1520 mm gauge railways. The article analyses the aspects of train traffic control and locomotive energy saving by using the coordinates of track profile change that have been received from GPS. In the article, achievements of Lithuanian railways (LG) in the area of train traffic control optimisation are presented.

  3. An Efficient AI Based Approach for Multimedia Traffic Management in Wireless Network

    Directory of Open Access Journals (Sweden)

    Abdul Hanan Abdullah

    2013-06-01

    Full Text Available This study presents Artificial Intelligence based channel estimation and monitoring technique call AIMonitoring System (AIMS, for integration of Multimedia traffic in wireless network. Through AIMS technique every node in the network has the capability to monitor the neighbour node transmission and also before sending the traffic. The sending node evaluates the SNR ratio as primary parameter and queue limit of the receiving node as secondary. With the help of AIMS every node has the pre-determined information about the selected channel as well as node. Based on conditional and distribution probability model, the proposed Bay Estimator model analyses the SNR ratio before forwarding the multimedia traffic on selected path. We determine the performance of our proposed technique by obtaining the recursive analysis matrix methodology. Amendment of pre-distinct parameters make us capable to maintain the quality of service, multipath adaptability for attack prevention, as well as minimize the packet loss ratio.

  4. A traffic model of optical networks based on time-space complexity and traffic grooming

    Institute of Scientific and Technical Information of China (English)

    Zhao Yongli; Zhang Jie; Han Dahai; Wang Lei; Chen Xiuzhong; Gu Wanyi

    2009-01-01

    This paper researched the traffic of optical networks in time-space complexity, proposed a novel traffic model for complex optical networks based on traffic grooming, designed a traffic generator GTS (generator based on time and space) with "centralized + distributed" idea, and then made a simulation in C language. Experiments results show that GTS can produce the virtual network topology which can change dynamically with the characteristic of scaling-free network. GTS can also groom the different traffic and trigger them under real-time or scheduling mechanisms, generating different optical connections. This traffic model is convenient for the simulation of optical networks considering the traffic complexity.

  5. Traffic Measurement for Traffic Engineering in IP/MPLS Based Telecom Core Networks

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Telecommunication networks will become IP-based networks with all voice, data and multimedia traffic carried as packets with appropriate quality and class of service for each traffic type. It is very important for service provider to apply Traffic Engineering (TE) with the dramatic growth of networks traffic. In this paper, we discuss traffic engineering based on IP/MPLS and emphasize traffic measurement in telecom core networks. We specify the technology and scientific principles of the measurement, modeling, characterization, and the traffic flow matrix. The paper concludes with a preliminary analysis of TE measurement and a discussion about the development of TE measurement.

  6. A real-time traffic scheduling algorithm in CDMA packet networks

    NARCIS (Netherlands)

    Zan, Lei; Heijenk, Geert; El Zarki, Magda; Gong, K.; Niu, Z.

    2003-01-01

    The demands for multimedia and packet data services over wireless devices have increased over the past few years. The direct impact on performance makes scheduling for real-time traffic important. This paper presents a novel scheduling algorithm called fair channel-dependent scheduling which schedul

  7. Dynamic Channel Allocation in Sectored Cellular Systems

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It is known that dynamic channel assignment(DCA) strategy outperforms the fixed channel assignment(FCA) strategy in omni-directional antenna cellular systems. One of the most important methods used in DCA was channel borrowing. But with the emergence of cell sectorization and spatial division multiple access(SDMA) which are used to increase the capacity of cellular systems, the channel assignment faces a series of new problems. In this paper, a dynamic channel allocation scheme based on sectored cellular systems is proposed. By introducing intra-cell channel borrowing (borrowing channels from neighboring sectors) and inter-cell channel borrowing (borrowing channels from neighboring cells) methods, previous DCA strategies, including compact pattern based channel borrowing(CPCB) and greedy based dynamic channel assignment(GDCA) schemes proposed by the author, are improved significantly. The computer simulation shows that either intra-cell borrowing scheme or inter-cell borrowing scheme is efficient enough to uniform and non-uniform traffic service distributions.

  8. Clear Channel Assessment in Integrated Medical Environments

    Directory of Open Access Journals (Sweden)

    Bin Zhen

    2008-03-01

    Full Text Available Complementary WLAN and WPAN technologies as well as other wireless technologies will play a fundamental role in the medical environments to support ubiquitous healthcare delivery. This paper investigates clear channel assessment (CCA and its impact on the coexistence of WLAN (IEEE 802.11 high rate direct sequence spread spectrum (HR/DSSS PHY and WPAN (IEEE 802.15.4b in the 2.4 GHz industrial, scientific, and medical (ISM band. We derived closed-form expressions of both energy-based CCA and feature-based CCA. We qualified unequal sensing abilities between them and termed this inequality asymmetric CCA, which is different from the traditional “hidden node” or “exposed node” issues in the homogeneous network. The energy-based CCA was considered in the considered integrated medical environment because the 2.4 GHz ISM band is too crowded to apply feature-based CCA. The WPAN is oversensitive to the 802.11 HR/DSSS signals and the WLAN is insensitive to the 802.15.4b signals. Choosing an optimal CCA threshold requires some prior knowledge of the underlying signals. In the integrated medical environment we considered here, energy-based CCA can effectively avoid possible packet collisions when they are close within the “heterogeneous exclusive CCA range” (HECR. However, when they are separated beyond the HECR, WPAN can still sense the 802.11 HR/DSSS signals, but WLAN loses its sense to the 802.15.4b signals. The asymmetric CCA leads to WPAN traffic in a position secondary to WLAN traffic.

  9. Clear Channel Assessment in Integrated Medical Environments

    Directory of Open Access Journals (Sweden)

    Hara Shinsuke

    2008-01-01

    Full Text Available Abstract Complementary WLAN and WPAN technologies as well as other wireless technologies will play a fundamental role in the medical environments to support ubiquitous healthcare delivery. This paper investigates clear channel assessment (CCA and its impact on the coexistence of WLAN (IEEE 802.11 high rate direct sequence spread spectrum (HR/DSSS PHY and WPAN (IEEE 802.15.4b in the 2.4 GHz industrial, scientific, and medical (ISM band. We derived closed-form expressions of both energy-based CCA and feature-based CCA. We qualified unequal sensing abilities between them and termed this inequality asymmetric CCA, which is different from the traditional "hidden node" or "exposed node" issues in the homogeneous network. The energy-based CCA was considered in the considered integrated medical environment because the 2.4 GHz ISM band is too crowded to apply feature-based CCA. The WPAN is oversensitive to the 802.11 HR/DSSS signals and the WLAN is insensitive to the 802.15.4b signals. Choosing an optimal CCA threshold requires some prior knowledge of the underlying signals. In the integrated medical environment we considered here, energy-based CCA can effectively avoid possible packet collisions when they are close within the "heterogeneous exclusive CCA range" (HECR. However, when they are separated beyond the HECR, WPAN can still sense the 802.11 HR/DSSS signals, but WLAN loses its sense to the 802.15.4b signals. The asymmetric CCA leads to WPAN traffic in a position secondary to WLAN traffic.

  10. Traffic Control in ATM Networks : Engineering Impacts of Realistic Traffic Processes

    OpenAIRE

    Jena, Ajit K.; Popescu, Adrian; Pruthi, Parag; Erramilli, Ashok

    1996-01-01

    This paper reviews the current state of the art in the rapidly developing areas of ATM traffic controls and traffic modeling, and identifies future research areas to facilitate the implementation of control methods that can support a desired quality of service without sacrificing network utilizations. Two sets of issues are identified, one on the impacts of realistic traffic on the efficacy of traffic controls in supporting specific traffic management objectives, and the other dealing with th...

  11. Modeling and Simulation of a Traffic Flow Model Considering the Influence of Traffic Interruption

    OpenAIRE

    Yang, Shu-hong; Li, Chui-Gui; Xia, Dong-Xue; Wang, Meng; Wang, Xiao-Rong

    2013-01-01

    In this paper, we present a new lattice model of traffic flow by considering the effects of traffic interruption probability. The stability condition of the proposed model is obtained by employing the linear stability theory. The results show that the stability of traffic flow is improved by considering the influence of traffic interruption. Applying the method of nonlinear analysis, the modified Korteweg-de Vries (mKdV) equation is derived to describe the traffic behavior near the critical p...

  12. Tailoring particle translocation via dielectrophoresis in pore channels.

    Science.gov (United States)

    Tanaka, Shoji; Tsutsui, Makusu; Theodore, Hu; Yuhui, He; Arima, Akihide; Tsuji, Tetsuro; Doi, Kentaro; Kawano, Satoyuki; Taniguchi, Masateru; Kawai, Tomoji

    2016-01-01

    Understanding and controlling electrophoretic motions of nanoscopic objects in fluidic channels are a central challenge in developing nanopore technology for molecular analyses. Although progress has been made in slowing the translocation velocity to meet the requirement for electrical detections of analytes via picoampere current measurements, there exists no method useful for regulating particle flows in the transverse directions. Here, we report the use of dielectrophoresis to manipulate the single-particle passage through a solid-state pore. We created a trap field by applying AC voltage between electrodes embedded in a low-aspect-ratio micropore. We demonstrated a traffic control of particles to go through center or near side surface via the voltage frequency. We also found enhanced capture efficiency along with faster escaping speed of particles by virtue of the AC-mediated electroosmosis. This method is compatible with nanopore sensing and would be widely applied for reducing off-axis effects to achieve single-molecule identification. PMID:27527126

  13. Memory effects in quantum channel discrimination

    OpenAIRE

    Chiribella G.; D'Ariano G.M.; Perinotti P.

    2008-01-01

    We consider quantum-memory assisted protocols for discriminating quantum channels. We show that for optimal discrimination of memory channels, memory assisted protocols are needed. This leads to a new notion of distance for channels with memory. For optimal discrimination and estimation of sets of unitary channels memory-assisted protocols are not required.

  14. Traffic Flow Prediction Using MI Algorithm and Considering Noisy and Data Loss Conditions: An Application to Minnesota Traffic Flow Prediction

    OpenAIRE

    Hosseini, Seyed Hadi; Moshiri, Behzad; Rahimi-Kian, Ashkan; Nadjar Araabi, Babak

    2014-01-01

    Traffic flow forecasting is useful for controlling traffic flow, traffic lights, and travel times. This study uses a multi-layer perceptron neural network and the mutual information (MI) technique to forecast traffic flow and compares the prediction results with conventional traffic flow forecasting methods. The MI method is used to calculate the interdependency of historical traffic data and future traffic flow. In numerical case studies, the proposed traffic flow forecasting method was test...

  15. Temporal Characteristics of Large IP Traffic Flows

    OpenAIRE

    Abrahamsson, Henrik; Ahlgren, Bengt

    2003-01-01

    Several studies of Internet traffic have shown that it is a small percentage of the flows that dominate the traffic. This is often referred to as the mice and elephants phenomenon. It has been proposed that this might be one of very few invariants of Internet traffic and that this property could somehow be used for traffic engineering purposes. The idea being that one in a scalable way could control a major part of the traffic by only keeping track of a small number of flows. But for this the...

  16. Urban traffic congestion propagation and bottleneck identification

    Institute of Scientific and Technical Information of China (English)

    LONG JianCheng; GAO ZiYou; REN HuaLing; LIAN AiPing

    2008-01-01

    Bottlenecks in urban traffic network are sticking points in restricting network col-lectivity traffic efficiency.To identify network bottlenecks effectively is a founda-tional work for improving network traffic condition and preventing traffic conges-tion.In this paper,a congestion propagation model of urban network traffic is proposed based on the cell transmission model (CTM).The proposed model in-cludes a link model,which describes flow propagation on links,and a node model,which represents link-to-link flow propagation.A new method of estimating average journey velocity (AJV) of both link and network is developed to identify network congestion bottlenecks.A numerical example is studied in Sioux Falls urban traffic network.The proposed model is employed in simulating network traffic propaga-tion and congestion bottleneck identification under different traffic demands.The simulation results show that continual increase of traffic demand is an immediate factor in network congestion bottleneck emergence and increase as well as re-ducing network collectivity capability.Whether a particular link will become a bot-tleneck is mainly determined by its position in network,its traffic flow (attributed to different OD pairs) component,and network traffic demand.

  17. A Wideband Channel Model for Intravehicular Nomadic Systems

    Directory of Open Access Journals (Sweden)

    François Bellens

    2011-01-01

    Full Text Available The increase in electronic entertainment equipments within vehicles has rendered the idea of replacing the wired links with intra-vehicle personal area networks. Ultra-wideband (UWB seems an appropriate candidate technology to meet the required data rates for interconnecting such devices. In particular, the multiband OFDM (MB-OFDM is able to provide very high transfer rates (up to 480 MBps over relatively short distances and low transmit power. In order to evaluate the performances of UWB systems within vehicles, a reliable channel model is needed. In this paper, a nomadic system where a base station placed in the center of the dashboard wants to communicate with fixed devices placed at the rear seat is investigated. A single-input single-output (SISO channel model for intra-vehicular communication (IVC systems is proposed, based on reverberation chamber theory. The model is based on measurements conducted in real traffic conditions, with a varying number of passengers in the car. Temporal variations of the wireless channels are also characterized and parametrized. The proposed model is validated by comparing model-independent statistics with the measurements.

  18. Modelling traffic pollution in streets

    Energy Technology Data Exchange (ETDEWEB)

    Berkowicz, R.; Hertel, O. [National Environmental Research Inst., Dept. of Atmospheric Environment, Roskilde (Denmark); Larsen, S.E.; Soerensen, N.N.; Nielsen, M. [Risoe National Lab., Dept. of Meteorology and Wind Energy, Roskilde (Denmark)

    1997-01-01

    This report concerns mainly the subject related to modelling air pollution from traffic in urban streets. A short overview is presented over the theoretical aspects and examples of most commonly used methods and models are given. Flow and dispersion conditions in street canyons are discussed and the presentation is substantiated with the analysis of the experimental data. The main emphasis is on the modelling methods that are suitable for routine applications and a more detailed presentation is given of the Operational Street Pollution Model (OSPM), which was developed by the National Environmental Research Institute. The model is used for surveillance of air pollution from traffic in Danish cities and also for special air pollution studies. (au) 76 refs.

  19. Crowding effects in vehicular traffic

    CERN Document Server

    Combinido, Jay Samuel L

    2012-01-01

    While the impact of crowding on the diffusive transport of molecules within a cell is widely studied in biology, it has thus far been neglected in traffic systems where bulk behavior is the main concern. Here, we study the effects of crowding due to car density and driving fluctuations on the transport of vehicles. Using a microscopic model for traffic, we found that crowding can push car movement from a superballistic down to a subdiffusive state. The transition is also associated with a change in the shape of the probability distribution of positions from negatively-skewed normal to an exponential distribution. Moreover, crowding broadens the distribution of cars' trap times and cluster sizes. At steady state, the subdiffusive state persists only when there is a large variability in car speeds. We further relate our work to prior findings from random walk models of transport in cellular systems.

  20. Transit Traffic Analysis Zone Delineating Method Based on Thiessen Polygon

    Directory of Open Access Journals (Sweden)

    Shuwei Wang

    2014-04-01

    Full Text Available A green transportation system composed of transit, busses and bicycles could be a significant in alleviating traffic congestion. However, the inaccuracy of current transit ridership forecasting methods is imposing a negative impact on the development of urban transit systems. Traffic Analysis Zone (TAZ delineating is a fundamental and essential step in ridership forecasting, existing delineating method in four-step models have some problems in reflecting the travel characteristics of urban transit. This paper aims to come up with a Transit Traffic Analysis Zone delineation method as supplement of traditional TAZs in transit service analysis. The deficiencies of current TAZ delineating methods were analyzed, and the requirements of Transit Traffic Analysis Zone (TTAZ were summarized. Considering these requirements, Thiessen Polygon was introduced into TTAZ delineating. In order to validate its feasibility, Beijing was then taken as an example to delineate TTAZs, followed by a spatial analysis of office buildings within a TTAZ and transit station departure passengers. Analysis result shows that the TTAZs based on Thiessen polygon could reflect the transit travel characteristic and is of in-depth research value.

  1. Real Time Network Traffic Monitoring

    OpenAIRE

    Tripp, Gerald

    1999-01-01

    This paper looks at the problems of real time network traffic monitoring. Some of the existing approaches are reviewed, looking at both simple filtering systems and also systems based on the use of finite state machines that can report specific events or capture data only when in particular states. Finally, some existing implementation techniques are examined and an outline proposal made for the design of a network monitoring system that uses finite state machines implemented using associativ...

  2. Field Programmable Gate Array (FPGA Model of Intelligent Traffic Light System with Saving Power

    Directory of Open Access Journals (Sweden)

    Ali Hashim Jryian

    2012-01-01

    Full Text Available In this paper, a FPGA model of intelligent traffic light system with power saving was built. The intelligent traffic light system consists of sensors placed on the side's ends of the intersection to sense the presence or absence of vehicles. This system reduces the waiting time when the traffic light is red, through the transition from traffic light state to the other state, when the first state spends a lot of time, because there are no more vehicles. The proposed system is built using VHDL, simulated using Xilinx ISE 9.2i package, and implemented using Spartan-3A XC3S700A FPGA kit. Implementation and Simulation behavioral model results show that the proposed intelligent traffic light system model satisfies the specified operational requirements.

  3. Beating the traffic with commuting alternatives

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-05-01

    This pamphlet describes how, by encouraging commuting options, local governments can help reduce air pollution, fuel consumption, and traffic congestion. Minimizing these problems makes the community more appealing to businesses, residents, and visitors and boosts the local economy. Approaches to alternative transportation are as varied as the communities devising and using them. But the critical factor is initiative from local governments, often one of communities largest employers. They can use and promote commuting alternatives among their employees. Local governments can also promote alternative transportation among other employers and the general public. They can provide information on commuting options, improve the infrastructure, and use local authority to require and reward those changes necessary to make alternative transportation a widely accepted part of community life. Best of all, local governments can lead by example and establish a template for other employers to follow.

  4. Decentralized and Tactical Air Traffic Flow Management

    Science.gov (United States)

    Bertsimas, Dimitris; Odoni, Amedeo R.

    1997-01-01

    This project dealt with the following topics: 1. Review and description of the existing air traffic flow management system (ATFM) and identification of aspects with potential for improvement. 2. Identification and review of existing models and simulations dealing with all system segments (enroute, terminal area, ground) 3. Formulation of concepts for overall decentralization of the ATFM system, ranging from moderate decentralization to full decentralization 4. Specification of the modifications to the ATFM system required to accommodate each of the alternative concepts. 5. Identification of issues that need to be addressed with regard to: determination of the way the ATFM system would be operating; types of flow management strategies that would be used; and estimation of the effectiveness of ATFM with regard to reducing delay and re-routing costs. 6. Concept evaluation through identification of criteria and methodologies for accommodating the interests of stakeholders and of approaches to optimization of operational procedures for all segments of the ATFM system.

  5. Intelligent Testing of Traffic Light Programs: Validation in Smart Mobility Scenarios

    Directory of Open Access Journals (Sweden)

    Javier Ferrer

    2016-01-01

    Full Text Available In smart cities, the use of intelligent automatic techniques to find efficient cycle programs of traffic lights is becoming an innovative front for traffic flow management. However, this automatic programming of traffic lights requires a validation process of the generated solutions, since they can affect the mobility (and security of millions of citizens. In this paper, we propose a validation strategy based on genetic algorithms and feature models for the automatic generation of different traffic scenarios checking the robustness of traffic light cycle programs. We have concentrated on an extensive urban area in the city of Malaga (in Spain, in which we validate a set of candidate cycle programs generated by means of four optimization algorithms: Particle Swarm Optimization for Traffic Lights, Differential Evolution for Traffic Lights, random search, and Sumo Cycle Program Generator. We can test the cycles of traffic lights considering the different states of the city, weather, congestion, driver expertise, vehicle’s features, and so forth, but prioritizing the most relevant scenarios among a large and varied set of them. The improvement achieved in solution quality is remarkable, especially for CO2 emissions, in which we have obtained a reduction of 126.99% compared with the experts’ solutions.

  6. A DISTRIBUTED DYNAMIC CHANNEL ALLOCATION IN CELLULAR COMMUNICATION

    Directory of Open Access Journals (Sweden)

    Dipti Varpe

    2011-07-01

    Full Text Available Now a days, mobile users are growing rapidly and the available frequency spectrum is limited. Therefore the available spectrum must be efficiently utilized. In response a large number of channel assignment and allocation policies have been proposed. Mostly Dynamic Channel Allocation (DCA has become an important subject of research and development for cellular networks. In this paper, we propose a distributed dynamic channel allocation (DDCA algorithm for originating calls. This algorithm is executed at each base station and to allocate the channel to mobile station, base station communicates with each other. In DDCA, the total number of channels is divided into three groups. Any cell in the cluster can acquire the channel group as long as no one of its adjacent cells is holding the same group. Due to this the cochannel interference is avoided. The result show blocking rate of distributed dynamic channel allocation is reduced as compared to dynamic channel allocation algorithm with non-uniform traffic distribution

  7. Traffic and Granular Flow ’07

    CERN Document Server

    Chevoir, François; Gondret, Philippe; Lassarre, Sylvain; Lebacque, Jean-Patrick; Schreckenberg, Michael

    2009-01-01

    This book covers several research fields, all of which deal with transport. Three main topics are treated: road traffic, granular matter, and biological transport. Different points of view, i.e. modelling, simulations, experiments, and phenomenological observations, are considered. Sub-topics include: highway or urban vehicular traffic (dynamics of traffic, macro/micro modelling, measurements, data analysis, security issues, psychological issues), pedestrian traffic, animal traffic (e.g. social insects), collective motion in biological systems (molecular motors...), granular flow (dense flows, intermittent flows, solid/liquid transition, jamming, force networks, fluid and solid friction), networks (biological networks, urban traffic, the internet, vulnerability of networks, optimal transport networks) and cellular automata applied to the various aforementioned fields.

  8. Image Processing Based Traffic Sign Recognising System

    Directory of Open Access Journals (Sweden)

    Neha M. Betgeri

    2013-11-01

    Full Text Available Road traffic signs provide important information for guiding, warning, or regulating the behaviors of driver in order to make driving safer and easier. Automatic recognition of traffic signs is important for an automated intelligent driving vehicle or for driver assistance systems. We have designed such a robust and a fault tolerant system so that it can be a part of the so called “Driver Support Systems”. This paper presents a study to recognize traffic sign patterns using Hough transform and slope detection method. Images are pre-processed with several image processing techniques, such as, boundary trace, edge detection, erosion etc. And then using slope detection technique, which is different and new approach than color based and shape based technique, respective traffic sign is detected. Which in turns give commands to wireless robot to move according to the detected traffic sign. (Here we are specifically considering traffic sign boards of arrow.

  9. Car-following models of vehicular traffic

    Institute of Scientific and Technical Information of China (English)

    翁彦琳; 吴铁军

    2002-01-01

    The Car-following model is a kind of microscopic simulation model for vehicular traffic, which describe the one-by-one following behaviors of vehides in the same traffic lane. As a common traffic phenomenon, following behavior is of great importance in the micro-study of intelligent traffic control.Compared with other traffic-flow models, car-following model embodies the human factors and feflects the real traffic sit-uation in a better way. This paper gives a systematic review of the development and actuality of car-following models by introducing and analyzing in detail the advantages and disavantages of GHR model, OV model,CA model and fuzzy-logic model. In addition, local stability and asymptotic stability of car-following models are discussed in this paper.

  10. Traffic Flow Management Wrap-Up

    Science.gov (United States)

    Grabbe, Shon

    2011-01-01

    Traffic Flow Management involves the scheduling and routing of air traffic subject to airport and airspace capacity constraints, and the efficient use of available airspace. Significant challenges in this area include: (1) weather integration and forecasting, (2) accounting for user preferences in the Traffic Flow Management decision making process, and (3) understanding and mitigating the environmental impacts of air traffic on the environment. To address these challenges, researchers in the Traffic Flow Management area are developing modeling, simulation and optimization techniques to route and schedule air traffic flights and flows while accommodating user preferences, accounting for system uncertainties and considering the environmental impacts of aviation. This presentation will highlight some of the major challenges facing researchers in this domain, while also showcasing recent innovations designed to address these challenges.

  11. Car-following models of vehicular traffic

    Institute of Scientific and Technical Information of China (English)

    翁彦琳; 吴铁军

    2002-01-01

    The Car-following models is a kind of microscopic simulation model f or vehicular traffic, which describe the one-by-one following behaviors of v ehicles in the same traffic lane. As a common traffic phenomenon, following behavior is of great importance in the micro-study of intelligent traffic control. Compared with other traffic-flow models, car-following model embodies the human factors a nd reflects the real traffic situation in a better way. This paper gives a syste matic review of the development and actuality of car-following models by introd u cing and analyzing in detail the advantages and disadvantages of GHR model, OV m odel, CA model and fuzzy-logic model. In addition, local stability and asymptot ic stability of car-following models are discussed in this paper.

  12. A Framework For Concept Drifting P2P Traffic Identification

    Directory of Open Access Journals (Sweden)

    Guanghui Yan

    2013-08-01

    Full Text Available Identification of network traffic using port-based or payload-based analysis is becoming increasing difficult with many Peer-to-Peer (P2P application using dynamic ports, masquerading techniques, and encryption to avoid detection. To overcome this problem, several machine learning technique were proposed to classify P2P traffics. But in the real P2P network environment, new communities of peers often attend and old communities of peers often leave. It requires the identification methods to be capable of coping with concept drift, and updating the model incrementally. In this paper, we present a concept-adapting algorithm CluMC which is based on streaming data mining techniques to identify P2P applications in Internet traffic. The CluMC use micro-cluster structures which contain potential micro-cluster structures and outlier micro-cluster structures to classify the P2P traffic and discover the concept drift with limited memory. Our performance study over a number of real data sets that we captured at a main gateway router demonstrates the effectiveness and efficiency of our method.

  13. Hazard based models for freeway traffic incident duration.

    Science.gov (United States)

    Tavassoli Hojati, Ahmad; Ferreira, Luis; Washington, Simon; Charles, Phil

    2013-03-01

    Assessing and prioritising cost-effective strategies to mitigate the impacts of traffic incidents and accidents on non-recurrent congestion on major roads represents a significant challenge for road network managers. This research examines the influence of numerous factors associated with incidents of various types on their duration. It presents a comprehensive traffic incident data mining and analysis by developing an incident duration model based on twelve months of incident data obtained from the Australian freeway network. Parametric accelerated failure time (AFT) survival models of incident duration were developed, including log-logistic, lognormal, and Weibul-considering both fixed and random parameters, as well as a Weibull model with gamma heterogeneity. The Weibull AFT models with random parameters were appropriate for modelling incident duration arising from crashes and hazards. A Weibull model with gamma heterogeneity was most suitable for modelling incident duration of stationary vehicles. Significant variables affecting incident duration include characteristics of the incidents (severity, type, towing requirements, etc.), and location, time of day, and traffic characteristics of the incident. Moreover, the findings reveal no significant effects of infrastructure and weather on incident duration. A significant and unique contribution of this paper is that the durations of each type of incident are uniquely different and respond to different factors. The results of this study are useful for traffic incident management agencies to implement strategies to reduce incident duration, leading to reduced congestion, secondary incidents, and the associated human and economic losses.

  14. Traffic Control System by Incorporating Message Forwarding Approach

    Directory of Open Access Journals (Sweden)

    K.V.Ramana Ph.D

    2011-10-01

    Full Text Available During the last few years, continuous progresses in wireless communications have opened new research fields in computer networking, aimed at extending data networks connectivity to environments where wired solutions are impracticable. Among these, vehicular traffic is attracting a growing attention from both academia and industry, due to the amount and importance of related distributive applications to mobile entertainment. VANETs are self-organized networks built up from moving vehicles, and are part of the broader class of MANETs. Because of these peculiar characteristics, VANETs require new networking techniques, whose feasibility and performance are usually tested by means of simulation. In order to meet performance goals, it is widely agreed that VANETs must rely heavily on node-to-node communication. In VANET, each vehicle acts as a node and communicates with other vehicles within the range or communicates with base stations. The main idea is to deploy a wireless communication network that has a capability of sending and receiving messages between transmitter and mobile devices in the particular network. Results can be shown using an effective VEINS Simulator. This Simulator can produce detailed vehicular movement traces and can simulate different traffic conditions through fully customizable scenarios. The Framework is expected to be employed using such simulator that makes use of traffic modulator, network simulator and coupling module that integrates the traffic and network.

  15. Traffic Control System by Incorporating Message Forwarding Approach

    Directory of Open Access Journals (Sweden)

    K.V.Ramana, Raghu.B.Korrapati, N.Pattabhi Ram & K.Syam Kumari

    2011-11-01

    Full Text Available During the last few years, continuous progresses in wireless communications have opened new researchfields in computer networking, aimed at extending data networks connectivity to environments wherewired solutions are impracticable. Among these, vehicular traffic is attracting a growing attention fromboth academia and industry, due to the amount and importance of related distributive applications tomobile entertainment. VANETs are self-organized networks built up from moving vehicles, and are part ofthe broader class of MANETs. Because of these peculiar characteristics, VANETs require newnetworking techniques, whose feasibility and performance are usually tested by means of simulation. Inorder to meet performance goals, it is widely agreed that VANETs must rely heavily on node-to-nodecommunication. In VANET, each vehicle acts as a node and communicates with other vehicles within therange or communicates with base stations. The main idea is to deploy a wireless communication networkthat has a capability of sending and receiving messages between transmitter and mobile devices in theparticular network. Results can be shown using an effective VEINS Simulator. This Simulator canproduce detailed vehicular movement traces and can simulate different traffic conditions through fullycustomizable scenarios. The Framework is expected to be employed using such simulator that makesuse of traffic modulator, network simulator and coupling module that integrates the traffic and network.

  16. MCMC simulation of GARCH model to forecast network traffic load

    Directory of Open Access Journals (Sweden)

    Akhter Raza Syed

    2012-05-01

    Full Text Available The performance of a computer network can be enhanced by increasing number of servers, upgrading the hardware, and gaining additional bandwidth but this solution require the huge amount to invest. In contrast to increasing the bandwidth and hardware resources, network traffic modeling play a significant role in enhancing the network performance. As the emphasis of telecommunication service providers shifted towards the high-speed networks providing integrated services at a prescribed Quality of Service (QoS, the role of accurate traffic models in network design and network simulation becomes ever more crucial. We analyze a traffic volume time series of internet requests made to a workstation. This series exhibits a long-range dependence and self-similarity in large time scale and exhibits multifractal in small time scale. In this paper, for this time series, we proposed Generalized Autoregressive Conditional Heteroscedastic, (GARCH model, and practical techniques for model fitting, Markov Chain Monte Carlo simulation and forecasting issues are demonstrated. The proposed model provides us simple and accurate approach for simulating internet data traffic patterns.

  17. A Simple Traffic Aware Algorithm To Improve Firewall Performance

    Directory of Open Access Journals (Sweden)

    Anirudhan Sudarsan

    2014-11-01

    Full Text Available Firewalls play an extremely important role in today’s networks. They are present universally in almost every corporate network across the globe and serve to protect such networks from unauthorized access. The firewall is most commonly implemented as a packet filter. The packet filter works by comparing incoming packets against a set of predefined rules called an access control list (ACL. It is vital to improve the performance of packet filtering firewalls as much as possible. Most of the research work in this area barring a few has not focused on utilizing traffic characteristics to improve the performance of packet filters. In this paper, we propose a simple algorithm that exploits traffic behavior by utilizing incoming traffic statistics to dynamically modify rule ordering in access control lists. Hence repeated packets or multiple packets from the same source require lesser number of comparisons before a rule is matched. When testing was performed for the proposed work using both a simulated firewall and simulated traffic the performance of the firewall showed considerable improvement.

  18. Air traffic management evaluation tool

    Science.gov (United States)

    Sridhar, Banavar (Inventor); Sheth, Kapil S. (Inventor); Chatterji, Gano Broto (Inventor); Bilimoria, Karl D. (Inventor); Grabbe, Shon (Inventor); Schipper, John F. (Inventor)

    2012-01-01

    Methods for evaluating and implementing air traffic management tools and approaches for managing and avoiding an air traffic incident before the incident occurs. A first system receives parameters for flight plan configurations (e.g., initial fuel carried, flight route, flight route segments followed, flight altitude for a given flight route segment, aircraft velocity for each flight route segment, flight route ascent rate, flight route descent route, flight departure site, flight departure time, flight arrival time, flight destination site and/or alternate flight destination site), flight plan schedule, expected weather along each flight route segment, aircraft specifics, airspace (altitude) bounds for each flight route segment, navigational aids available. The invention provides flight plan routing and direct routing or wind optimal routing, using great circle navigation and spherical Earth geometry. The invention provides for aircraft dynamics effects, such as wind effects at each altitude, altitude changes, airspeed changes and aircraft turns to provide predictions of aircraft trajectory (and, optionally, aircraft fuel use). A second system provides several aviation applications using the first system. Several classes of potential incidents are analyzed and averted, by appropriate change en route of one or more parameters in the flight plan configuration, as provided by a conflict detection and resolution module and/or traffic flow management modules. These applications include conflict detection and resolution, miles-in trail or minutes-in-trail aircraft separation, flight arrival management, flight re-routing, weather prediction and analysis and interpolation of weather variables based upon sparse measurements. The invention combines these features to provide an aircraft monitoring system and an aircraft user system that interact and negotiate changes with each other.

  19. Traffic Engineering With Traditional IP Routing Protocols

    OpenAIRE

    Fortz, Bernard; Rexford, Jennifer; Thorup, Mikkel

    2002-01-01

    Traffic engineering involves adapting the routing of traffic to the network conditions, with the joint goals of good user performance and efficient use of network resources. In this paper, we describe an approach to intradomain traffic engineering that works within the existing deployed base of Interior Gateway Protocols (IGPs), such as Open Shortest Path First (OSPF) and Intermediate System-Intermediate System (IS-IS). We explain how to adapt the configuration of link weights, based on a ...

  20. Fractal Analysis On Internet Traffic Time Series

    CERN Document Server

    Chong, K B

    2002-01-01

    Fractal behavior and long-range dependence have been observed in tele-traffic measurement and characterization. In this paper we show results of application of the fractal analysis to internet traffic via various methods. Our result demonstrate that the internet traffic exhibits self-similarity. Time-scale analysis show to be an effective way to characterize the local irregularity. Based on the result of this study, these two Internet time series exhibit fractal characteristic with long-range dependence.

  1. Modelling and control of road traffic networks

    OpenAIRE

    Haut, Bertrand

    2007-01-01

    Road traffic networks offer a particularly challenging research subject to the control community. The traffic congestion around big cities is constantly increasing and is now becoming a major problem. However, the dynamics of a road network exhibit some complex behaviours such as nonlinearities, delays and saturation effects that prevent the use of some classical control algorithms. This thesis presents different models and control algorithms used for road traffic networks. The dynamics ar...

  2. Residential Exposure to Traffic and Spontaneous Abortion

    OpenAIRE

    Green, Rochelle S; Malig, Brian; Windham, Gayle C.; Fenster, Laura; Ostro, Bart; Swan, Shanna

    2009-01-01

    Background Studies have shown associations between air pollution or traffic exposure and adverse birth outcomes, such as low birth weight. However, very few studies have examined the effect of traffic emissions on spontaneous abortion (SAB). Objective The goal of this study was to determine whether residential exposure to vehicular traffic was associated with SAB. Methods Pregnant women from a prepaid health plan in California were recruited into a prospective cohort study in 1990–1991. Three...

  3. Deep Learning Predictors for Traffic Flows

    OpenAIRE

    Polson, Nicholas; Sokolov, Vadim

    2016-01-01

    We develop a deep learning predictor for modeling traffic flows. The challenge arises as traffic flows have sharp nonlinearities resulting from transitions from free flow to breakdown and then to congested flow. Our methodology uses a deep learning architecture to capture nonlinear spatio-temporal flow effects. We show how traffic flow data, from road sensors, can be predicted using deep learning. For comparison, we use a benchmark sparse $\\ell_1$ trend filter and we illustrate our methodolog...

  4. LED Traffic Light as Communication Device

    OpenAIRE

    Kwan, TO; Chan, CH; Liu, HS; Pang, GKH

    1999-01-01

    The visible light from an LED (light emitting diode) traffic light can be modulated and encoded with information. Hence, it can be used for the broadcasting of audio messages or any traffic or road information. Essentially all LED traffic lights can be used as communications devices. The paper focuses on the description of an audio information system made up of high brightness, visible light emitting diodes (LEDs) in which one or more LEDs are modulated and encoded with audio messages. The sy...

  5. Stochastic Modeling of Traffic Air Pollution

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    2014-01-01

    In this paper, modeling of traffic air pollution is discussed with special reference to infrastructures. A number of subjects related to health effects of air pollution and the different types of pollutants are briefly presented. A simple model for estimating the social cost of traffic related air...... and using simple Monte Carlo techniques to obtain a stochastic estimate of the costs of traffic air pollution for infrastructures....

  6. Traffic calming schemes : opportunities and implementation strategies.

    OpenAIRE

    Schagen, I.N.L.G. van (samenst.)

    2003-01-01

    Commissioned by the Swedish National Road Authority, this report aims to provide a concise overview of knowledge of and experiences with traffic calming schemes in urban areas, both on a technical level and on a policy level. Traffic calming refers to a combination of network planning and engineering measures to enhance road safety as well as other aspects of liveability for the citizens. More specifically, in the current report the starting point is that traffic calming schemes in residentia...

  7. The use of Grey System Theory in predicting the road traffic accident in Fars province in Iran

    Directory of Open Access Journals (Sweden)

    Ali Mohammadi

    2011-10-01

    Full Text Available Traffic accidents have become a more and more important factor that restrict the development of economy and threaten the safety of human beings. Considering the complexity and uncertainty of the influencing factors on traffic accidents, traffic accident forecasting can be regarded as a grey system with unknown and known information, so be analyzed by grey system theory. Grey models require only a limited amount of data to estimate the behavior of unknown systems. In this paper, first, the original predicted values of road traffic accidents are separately obtained by the GM (1,1 model, the Verhulst model and the DGM(2,1 model. The results of these models on predicting road traffic accident show that the forecasting accuracy of the GM(1,1 is higher than the Verhulst model and the DGM(2,1 model. Then, the GM(1,1 model is applied to predict road traffic accident in Fars province.

  8. Mitochondrial Ion Channels

    Science.gov (United States)

    O’Rourke, Brian

    2009-01-01

    In work spanning more than a century, mitochondria have been recognized for their multifunctional roles in metabolism, energy transduction, ion transport, inheritance, signaling, and cell death. Foremost among these tasks is the continuous production of ATP through oxidative phosphorylation, which requires a large electrochemical driving force for protons across the mitochondrial inner membrane. This process requires a membrane with relatively low permeability to ions to minimize energy dissipation. However, a wealth of evidence now indicates that both selective and nonselective ion channels are present in the mitochondrial inner membrane, along with several known channels on the outer membrane. Some of these channels are active under physiological conditions, and others may be activated under pathophysiological conditions to act as the major determinants of cell life and death. This review summarizes research on mitochondrial ion channels and efforts to identify their molecular correlates. Except in a few cases, our understanding of the structure of mitochondrial ion channels is limited, indicating the need for focused discovery in this area. PMID:17059356

  9. Critical density of urban traffic

    CERN Document Server

    da Silva, Adilton Jose

    2010-01-01

    A modified version of the Intelligent Driver Model was used to simulate traffic in the district of Afogados, in the city of Recife, Brazil, with the objective to verify whether the complexity of the underlying street grid, with multiple lane streets, crossings, and semaphores, is capable of exhibiting the effect of critical density: appearance of a maximum in the vehicle flux versus density curve. Numerical simulations demonstrate that this effect indeed is observed on individual avenues, while the phase offset among the avenues results in damping of this effect for the region as a whole.

  10. A study into ward traffic

    Directory of Open Access Journals (Sweden)

    P. Hardcatle

    1982-09-01

    Full Text Available The study was undertaken in 1980 and was prompted by a need to highlight some of the problems associated with the ward milieu, both for patient care and for nurse teaching. Being associated at that time with the clinical teaching department the author was very interested in looking into the amount of traffic entering the ward area. It seemed that the ward sister had a very difficult task in providing a therapeutic environment for her patients, and that patient care was always being criticised with little thought to what was actually occurring in the ward.

  11. On the reproducibility of spatiotemporal traffic dynamics with microscopic traffic models

    Science.gov (United States)

    Knorr, Florian; Schreckenberg, Michael

    2012-10-01

    Traffic flow is a very prominent example of a driven non-equilibrium system. A characteristic phenomenon of traffic dynamics is the spontaneous and abrupt drop of the average velocity on a stretch of road leading to congestion. Such a traffic breakdown corresponds to a boundary-induced phase transition from free flow to congested traffic. In this paper, we study the ability of selected microscopic traffic models to reproduce a traffic breakdown, and we investigate its spatiotemporal dynamics. For our analysis, we use empirical traffic data from stationary loop detectors on a German Autobahn showing a spontaneous breakdown. We then present several methods to assess the results and compare the models with each other. In addition, we will also discuss some important modeling aspects and their impact on the resulting spatiotemporal pattern. The investigation of different downstream boundary conditions, for example, shows that the physical origin of the traffic breakdown may be artificially induced by the setup of the boundaries.

  12. On the reproducibility of spatiotemporal traffic dynamics with microscopic traffic models

    CERN Document Server

    Knorr, Florian

    2012-01-01

    Traffic flow is a very prominent example of a driven non-equilibrium system. A characteristic phenomenon of traffic dynamics is the spontaneous and abrupt drop of the average velocity on a stretch of road leading to congestion. Such a traffic breakdown corresponds to a boundary-induced phase transition from free flow to congested traffic. In this paper, we study the ability of selected microscopic traffic models to reproduce a traffic breakdown, and we investigate its spatiotemporal dynamics. For our analysis, we use empirical traffic data from stationary loop detectors on a German Autobahn showing a spontaneous breakdown. We then present several methods to assess the results and compare the models with each other. In addition, we will also discuss some important modeling aspects and their impact on the resulting spatiotemporal pattern. The investigation of different downstream boundary conditions, for example, shows that the physical origin of the traffic breakdown may be artificially induced by the setup of...

  13. Real-Time Corrected Traffic Correlation Model for Traffic Flow Forecasting

    Directory of Open Access Journals (Sweden)

    Hua-pu Lu

    2015-01-01

    Full Text Available This paper focuses on the problems of short-term traffic flow forecasting. The main goal is to put forward traffic correlation model and real-time correction algorithm for traffic flow forecasting. Traffic correlation model is established based on the temporal-spatial-historical correlation characteristic of traffic big data. In order to simplify the traffic correlation model, this paper presents correction coefficients optimization algorithm. Considering multistate characteristic of traffic big data, a dynamic part is added to traffic correlation model. Real-time correction algorithm based on Fuzzy Neural Network is presented to overcome the nonlinear mapping problems. A case study based on a real-world road network in Beijing, China, is implemented to test the efficiency and applicability of the proposed modeling methods.

  14. Urban Traffic Information Service Application Grid

    Institute of Scientific and Technical Information of China (English)

    Chang-Jun Jiang; Yang Luo; An-Qing Zhou; Lin Chen; Lei Liu; Zhao-Hui Zhang; Guo-Sun Zeng; Hong-Zhong Chen; Duo-Qian Miao; Yu Fang; Xiao-Feng Tao; Qing Zhi; Feng Yue

    2005-01-01

    Traffic information processing is very complicated because of dynamic, cooperative and distributed features. This paper describes the prototype system version 2.0 of Urban Traffic Information Service Application Grid (UTISAG),which is based on the previous version. In this version, a new architecture and more enhanced services are introduced.The remarkable characteristic of the new system is providing dynamic information services for travelers by grid technology. Therefore, the key research includes integrating large multi-source traffic data, forecasting route status, simulating regional traffic flow parallelly, and implementing optimum dynamic travel scheme based on massive GPS data.

  15. Air Traffic Management Research at NASA Ames

    Science.gov (United States)

    Davis, Thomas J.

    2012-01-01

    The Aviation Systems Division at the NASA Ames Research Center conducts leading edge research in air traffic management concepts and technologies. This overview will present concepts and simulation results for research in traffic flow management, safe and efficient airport surface operations, super density terminal area operations, separation assurance and system wide modeling and simulation. A brief review of the ongoing air traffic management technology demonstration (ATD-1) will also be presented. A panel discussion, with Mr. Davis serving as a panelist, on air traffic research will follow the briefing.

  16. A Brief Introduction of Air Traffic Management

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    Air Traffic Management (ATM) started publication in 1995 by Air Traffic Management Bureau of CAAC. It is the first magazine about ATM field in CAAC. The chairman of Editorial Board of ATM is Mr. Bao Peide, Vice Minister of CAAC. Mr. Chen Ziye, Vice President of the 1st Research Institute of CAAC and Chen Xuhua, General Director of Air Traffic Management Bureau are vice chairmen of the editorial board, and six general directors of local air traffic management bureau and some professors and experts are members of the editorial board.

  17. A queuing model for road traffic simulation

    International Nuclear Information System (INIS)

    We present in this article a stochastic queuing model for the raod traffic. The model is based on the M/G/c/c state dependent queuing model, and is inspired from the deterministic Godunov scheme for the road traffic simulation. We first propose a variant of M/G/c/c state dependent model that works with density-flow fundamental diagrams rather than density-speed relationships. We then extend this model in order to consider upstream traffic demand as well as downstream traffic supply. Finally, we show how to model a whole raod by concatenating raod sections as in the deterministic Godunov scheme

  18. Robust Traffic Flow Management: Coevolutionary Approach Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We will develop a Coevolutionary Decision Support Tool (CDST) that explicitly incorporates weather uncertainty (non-probabilistically) into strategic Traffic Flow...

  19. Adaptive radio resource allocation for multiple traffic OFDMA broadband wireless access system

    Institute of Scientific and Technical Information of China (English)

    LU Yan-hui; LUO Tao; YIN Chang-chuan; YUE Guang-xin

    2006-01-01

    In this article, an adaptive radio resource allocation algorithm applied to multiple traffic orthogonal frequency division multiple access (OFDMA) system is proposed, which distributes subcarriers and bits among users according to their different quality of service requirements and traffic type. By classifying and prioritizing the users based on their traffic characteristic and ensuring resource for higher priority users, the new scheme decreases tremendously the outage probability of the users requiting a real-time transmission without impact on the spectrum efficiency of system, as well as the outage probability of data users is not increased compared with the radio resource allocation methods published.

  20. REDUCTION IN PROBABILITY OF TRAFFIC CONGESTION ON HIGH-CLASS ROAD USING RAMP ACCESS CONTROL

    Directory of Open Access Journals (Sweden)

    R. Yu. Lagerev

    2016-01-01

    Full Text Available Мerging traffic junctions on high-class roads are considered as bottlenecks in the network and quality of their operation determines a probability for formation of traffic congestions. Investigations on congestion situations in the merging zones of ramp and freeway traffic flows have demonstrated that queuing ramp traffic flow leads to formation of so called “turbulence” effect due to re-arrangement of transport facilities and reduction in their speed on main road direction. Having high queuing traffic flow on main road the “turbulence” component can result in formation of an impact blow in the main traffic flow. It has been proved that an impact of the ramp traffic flow on congestion probability is higher in comparison with main road traffic flow. The paper makes it possible to establish that some transport facilities moving along a high-way simul taneously occupy two lanes in the merging traffic zones and they reduce capacity of the used road section. It is necessary to take into account this specific feature and it is necessary to pay attention to it in the zones of “turbulence” effect formation. The paper presents main approaches, methodology, principles and stages required for access control of high-class roads which are directed on higher quality of their operation including improvement of road traffic safety. The paper proposes a methodоlogy that allows to evaluate and optimize ramp control in the context of a transport queue length minimization at adjoining ramps for the purposes of probability reduction in transport congestion.

  1. Characteristics of ant-inspired traffic flow: Applying the social insect metaphor to traffic models

    OpenAIRE

    John, Alexander; Schadschneider, Andreas; Chowdhury, Debashish; Nishinari, Katsuhiro

    2009-01-01

    We investigate the organization of traffic flow on preexisting uni- and bidirectional ant trails. Our investigations comprise a theoretical as well as an empirical part. We propose minimal models of uni- and bi-directional traffic flow implemented as cellular automata. Using these models, the spatio-temporal organization of ants on the trail is studied. Based on this, some unusual flow characteristics which differ from those known from other traffic systems, like vehicular traffic or pedestri...

  2. Influence of Traffic Mix on PCU Value of Vehicles under Heterogeneous Traffic Conditions

    OpenAIRE

    Prema Somanathan Praveen; Venkatachalam Thamizh Arasan

    2013-01-01

    Study of the basic traffic flow characteristics like traffic volume is the pre-requisites for the effective planning, design, operation and management of roadway systems. Traffic in developing countries like India is heterogeneous in nature consisting of vehicles of different categories with widely varying dimensional and operational characteristics. The moving vehicles of heterogeneous traffic occupy any convenient lateral position on the road without any lane discipline, based on the availa...

  3. Selecting noise source and traffic representations that capture urban traffic noise dynamics

    OpenAIRE

    CAN, Arnaud; Leclercq, Ludovic; Lelong, Joël

    2009-01-01

    Considering traffic dynamics greatly improves noise estimation in urban area. This can be achieved by coupling a dynamic traffic model with both noise emission laws and sound propagation calculation. Determining the relevant noise source and traffic representations to estimate classical noise descriptors (LAeq and statistical descriptors) near traffic signals has been recently studied. This research topic is extended in this paper to more specific descriptors which are able to capture noise d...

  4. 77 FR 18297 - Air Traffic Noise, Fuel Burn, and Emissions Modeling Using the Aviation Environmental Design Tool...

    Science.gov (United States)

    2012-03-27

    ... Federal Aviation Administration Air Traffic Noise, Fuel Burn, and Emissions Modeling Using the Aviation... one airport, or includes actions above 3,000 feet , noise modeling will be conducted using [the Noise... required tool for noise, fuel burn, and emissions modeling of air traffic airspace and procedure...

  5. The traffic crisis and a tale of two cities: Traffic and air quality in Bangkok and Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Pendakur, V.S.; Badami, M.G.

    1995-12-31

    This paper focuses on congestion management techniques, traffic congestion levels and air quality. By using data from Bangkok and Mexico City, it illustrates the need for drastic changes in transportation policy tools and techniques for congestion management and for improving environmental quality. New approaches to investment and regulatory policy analysis and implementation are suggested. This requires the inclusion of all costs and benefits (economic and ecological) in the policy matrix so that investment and regulatory policies act in unison. Megacities are dominant in social, political and economic terms. 30 to 60% of national GDP is typically produced in these cities. Their human and motor vehicle populations have been doubling every 15-20 and 6-10 years respectively. They also have the most severe traffic congestion and air quality problems. They have the nation`s highest incidence of poverty and absolute poverty. Large portions of their populations endure severely unhealthy housing and sanitation conditions. Following are important characteristics of urban transportation systems in the megacities: the city centres are heavily congested with motorized traffic; traffic crawl rates vary from 2 to 10 km/hr; car and motorcycle ownership are increasing at annual rates of 10-12% and 15-20% respectively; significant air pollution with no relief in sight; TDM strategies are primarily creating new supply of road capacity; fairly high transit trips with substantial transit investments; weak air pollution monitoring and enforcement; and fairly cheap fuel and high costs of vehicles.

  6. Simple and stable dynamic traffic engineering for provider scale ethernet

    OpenAIRE

    Teixeira, António Edgar Carvalho

    2010-01-01

    The 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 host...

  7. Traffic Light Control by Multiagent Reinforcement Learning Systems

    NARCIS (Netherlands)

    Bakker, B.; Whiteson, S.; Kester, L.J.H.M.; Groen, F.C.A.

    2010-01-01

    Traffic light control is one of the main means of controlling road traffic. Improving traffic control is important because it can lead to higher traffic throughput and reduced traffic congestion. This chapter describes multiagent reinforcement learning techniques for automatic optimization of traffi

  8. Traffic light control by multiagent reinforcement learning systems

    NARCIS (Netherlands)

    B. Bakker; S. Whiteson; L. Kester; F.C.A. Groen

    2010-01-01

    Traffic light control is one of the main means of controlling road traffic. Improving traffic control is important because it can lead to higher traffic throughput and reduced traffic congestion. This chapter describes multiagent reinforcement learning techniques for automatic optimization of traffi

  9. 14 CFR 93.123 - High density traffic airports.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false High density traffic airports. 93.123... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93.123 High density traffic airports. (a) Each of the following airports is designated as a...

  10. A method for classification of network traffic based on C5.0 Machine Learning Algorithm

    DEFF Research Database (Denmark)

    Bujlow, Tomasz; Riaz, M. Tahir; Pedersen, Jens Myrup

    2012-01-01

    Monitoring of the network performance in high-speed Internet infrastructure is a challenging task, as the requirements for the given quality level are service-dependent. Backbone QoS monitoring and analysis in Multi-hop Networks requires therefore knowledge about types of applications forming...... current network traffic. To overcome the drawbacks of existing methods for traffic classification, usage of C5.0 Machine Learning Algorithm (MLA) was proposed. On the basis of statistical traffic information received from volunteers and C5.0 algorithm we constructed a boosted classifier, which was shown...... and classification, an algorithm for recognizing flow direction and the C5.0 itself. Classified applications include Skype, FTP, torrent, web browser traffic, web radio, interactive gaming and SSH. We performed subsequent tries using different sets of parameters and both training and classification options...

  11. A Behavioural Model of Traffic Congestion: Endogenizing Speed Choice, Traffic Safety and Time Losses

    NARCIS (Netherlands)

    Verhoef, E.T.; Rouwendal, J.

    2004-01-01

    Conventional economic models of traffic congestion assume that the relation between traffic flow and speed is a technical one. This paper develops a behavioural model of traffic congestion, in which drivers optimize their speeds by trading off time costs, expected accident costs and fuel costs. Sinc

  12. Influence of Traffic Mix on PCU Value of Vehicles under Heterogeneous Traffic Conditions

    Directory of Open Access Journals (Sweden)

    Prema Somanathan Praveen

    2013-09-01

    Full Text Available Study of the basic traffic flow characteristics like traffic volume is the pre-requisites for the effective planning, design, operation and management of roadway systems. Traffic in developing countries like India is heterogeneous in nature consisting of vehicles of different categories with widely varying dimensional and operational characteristics. The moving vehicles of heterogeneous traffic occupy any convenient lateral position on the road without any lane discipline, based on the availability of space. The interaction between moving vehicles under such traffic condition is highly complex in nature, which can be represented in terms of the amount of impedance caused to flow of traffic by a vehicle type in comparison with that of standard vehicle (passenger car. Passenger Car Unit (PCU can be an appropriate measure to represent the relative impedance caused by a vehicle in heterogeneous traffic. This paper is concerned with the application micro-simulation technique to derive equivalency values (PCU factors on a purely homogeneous (cars-only traffic stream as well as on a heterogeneous traffic stream for different categories of road vehicles over a wide range of traffic flow and compositions on four-lane divided urban roads in India. The PCU values obtained for the different types of vehicles, for a wide range of traffic volume and composition, indicate that the PCU values of a vehicle type significantly changes with change in traffic volume and composition.

  13. Urban traffic noise and the relation to urban density, form, and traffic elasticity

    NARCIS (Netherlands)

    Salomons, E.M.; Berghauser Pont, M.

    2012-01-01

    Traffic noise in cities has serious effects on the inhabitants. Well-known effects are annoyance and sleep disturbance, but long-term health effects such as cardiovascular disease have also been related to traffic noise. The spatial distribution of traffic noise in a city is related to the distribut

  14. Traffic Dynamics of Computer Networks

    CERN Document Server

    Fekete, Attila

    2008-01-01

    Two important aspects of the Internet, namely the properties of its topology and the characteristics of its data traffic, have attracted growing attention of the physics community. My thesis has considered problems of both aspects. First I studied the stochastic behavior of TCP, the primary algorithm governing traffic in the current Internet, in an elementary network scenario consisting of a standalone infinite-sized buffer and an access link. The effect of the fast recovery and fast retransmission (FR/FR) algorithms is also considered. I showed that my model can be extended further to involve the effect of link propagation delay, characteristic of WAN. I continued my thesis with the investigation of finite-sized semi-bottleneck buffers, where packets can be dropped not only at the link, but also at the buffer. I demonstrated that the behavior of the system depends only on a certain combination of the parameters. Moreover, an analytic formula was derived that gives the ratio of packet loss rate at the buffer ...

  15. Tractor accidents in Swedish traffic.

    Science.gov (United States)

    Pinzke, Stefan; Nilsson, Kerstin; Lundqvist, Peter

    2012-01-01

    The objective of this study is to reach a better understanding of accidents on Swedish roads involving tractors and to suggest ways of preventing them. In an earlier study we analyzed police-reported fatal accidents and accidents that led to physical injuries from 1992 to 2005. During each year of this period, tractors were involved in 128 traffic accidents on average, an average of 7 people were killed, 44 sustained serious injuries, and 143 sustained slight injuries. The number of fatalities in these tractor accidents was about 1.3% of all deaths in traffic accidents in Sweden. Cars were most often involved in the tractor accidents (58%) and 15% were single vehicle accidents. The mean age of the tractor driver involved was 39.8 years and young drivers (15-24 years) were overrepresented (30%). We are now increasing the data collected with the years 2006-2010 in order to study the changes in the number of accidents. Special attention will be given to the younger drivers and to single vehicle accidents. Based on the results we aim to develop suggestions for reducing road accidents, e.g. including measures for making farm vehicles more visible and improvement of the training provided at driving schools. PMID:22317543

  16. Geometric pumping in autophoretic channels

    CERN Document Server

    Michelin, Sebastien; De Canio, Gabriele; Lobato-Dauzier, Nicolas; Lauga, Eric

    2015-01-01

    Many microfluidic devices use macroscopic pressure differentials to overcome viscous friction and generate flows in microchannels. In this work, we investigate how the chemical and geometric properties of the channel walls can drive a net flow by exploiting the autophoretic slip flows induced along active walls by local concentration gradients of a solute species. We show that chemical patterning of the wall is not required to generate and control a net flux within the channel, rather channel geometry alone is sufficient. Using numerical simulations, we determine how geometric characteristics of the wall influence channel flow rate, and confirm our results analytically in the asymptotic limit of lubrication theory.

  17. Leukotriene-C4 Synthase, a Critical Enzyme in the Activation of Store-independent Orai1/Orai3 Channels, Is Required for Neointimal Hyperplasia*

    Science.gov (United States)

    Zhang, Wei; Zhang, Xuexin; González-Cobos, José C.; Stolwijk, Judith A.; Matrougui, Khalid; Trebak, Mohamed

    2015-01-01

    Leukotriene-C4 synthase (LTC4S) generates LTC4 from arachidonic acid metabolism. LTC4 is a proinflammatory factor that acts on plasma membrane cysteinyl leukotriene receptors. Recently, however, we showed that LTC4 was also a cytosolic second messenger that activated store-independent LTC4-regulated Ca2+ (LRC) channels encoded by Orai1/Orai3 heteromultimers in vascular smooth muscle cells (VSMCs). We showed that Orai3 and LRC currents were up-regulated in medial and neointimal VSMCs after vascular injury and that Orai3 knockdown inhibited LRC currents and neointimal hyperplasia. However, the role of LTC4S in neointima formation remains unknown. Here we show that LTC4S knockdown inhibited LRC currents in VSMCs. We performed in vivo experiments where rat left carotid arteries were injured using balloon angioplasty to cause neointimal hyperplasia. Neointima formation was associated with up-regulation of LTC4S protein expression in VSMCs. Inhibition of LTC4S expression in injured carotids by lentiviral particles encoding shRNA inhibited neointima formation and inward and outward vessel remodeling. LRC current activation did not cause nuclear factor for activated T cells (NFAT) nuclear translocation in VSMCs. Surprisingly, knockdown of either LTC4S or Orai3 yielded more robust and sustained Akt1 and Akt2 phosphorylation on Ser-473/Ser-474 upon serum stimulation. LTC4S and Orai3 knockdown inhibited VSMC migration in vitro with no effect on proliferation. Akt activity was suppressed in neointimal and medial VSMCs from injured vessels at 2 weeks postinjury but was restored when the up-regulation of either LTC4S or Orai3 was prevented by shRNA. We conclude that LTC4S and Orai3 altered Akt signaling to promote VSMC migration and neointima formation. PMID:25540197

  18. Developing a Minimum Data Set for an Information Management System to Study Traffic Accidents in Iran

    Science.gov (United States)

    Mohammadi, Ali; Ahmadi, Maryam; Gharagozlu, Alireza

    2016-01-01

    Background: Each year, around 1.2 million people die in the road traffic incidents. Reducing traffic accidents requires an exact understanding of the risk factors associated with traffic patterns and behaviors. Properly analyzing these factors calls for a comprehensive system for collecting and processing accident data. Objectives: The aim of this study was to develop a minimum data set (MDS) for an information management system to study traffic accidents in Iran. Materials and Methods: This descriptive, cross-sectional study was performed in 2014. Data were collected from the traffic police, trauma centers, medical emergency centers, and via the internet. The investigated resources for this study were forms, databases, and documents retrieved from the internet. Forms and databases were identical, and one sample of each was evaluated. The related internet-sourced data were evaluated in their entirety. Data were collected using three checklists. In order to arrive at a consensus about the data elements, the decision Delphi technique was applied using questionnaires. The content validity and reliability of the questionnaires were assessed by experts’ opinions and the test-retest method, respectively. Results: An (MDS) of a traffic accident information management system was assigned to three sections: a minimum data set for traffic police with six classes, including 118 data elements; a trauma center with five data classes, including 57 data elements; and a medical emergency center, with 11 classes, including 64 data elements. Conclusions: Planning for the prevention of traffic accidents requires standardized data. As the foundation for crash prevention efforts, existing standard data infrastructures present policymakers and government officials with a great opportunity to strengthen and integrate existing accident information systems to better track road traffic injuries and fatalities. PMID:27247791

  19. Data preprocessing for a vehicle-based localization system used in road traffic applications

    Science.gov (United States)

    Patelczyk, Timo; Löffler, Andreas; Biebl, Erwin

    2016-09-01

    This paper presents a fixed-point implementation of the preprocessing using a field programmable gate array (FPGA), which is required for a multipath joint angle and delay estimation (JADE) used in road traffic applications. This paper lays the foundation for many model-based parameter estimation methods. Here, a simulation of a vehicle-based localization system application for protecting vulnerable road users, which were equipped with appropriate transponders, is considered. For such safety critical applications, the robustness and real-time capability of the localization is particularly important. Additionally, a motivation to use a fixed-point implementation for the data preprocessing is a limited computing power of the head unit of a vehicle. This study aims to process the raw data provided by the localization system used in this paper. The data preprocessing applied includes a wideband calibration of the physical localization system, separation of relevant information from the received sampled signal, and preparation of the incoming data via further processing. Further, a channel matrix estimation was implemented to complete the data preprocessing, which contains information on channel parameters, e.g., the positions of the objects to be located. In the presented case of a vehicle-based localization system application we assume an urban environment, in which multipath propagation occurs. Since most methods for localization are based on uncorrelated signals, this fact must be addressed. Hence, a decorrelation of incoming data stream in terms of a further localization is required. This decorrelation was accomplished by considering several snapshots in different time slots. As a final aspect of the use of fixed-point arithmetic, quantization errors are considered. In addition, the resources and runtime of the presented implementation are discussed; these factors are strongly linked to a practical implementation.

  20. Reduction of the air traffic's contribution to climate change: A REACT4C case study

    OpenAIRE

    Grewe, V; Champougny, T.; Matthes, Sigrun; Frömming, Christine; Brinkop, Sabine; Soevde, Amund; Irvine, Emma A.; Halscheidt, Lucia

    2014-01-01

    Air traffic alters the atmospheric composition and thereby contributes to climate change. Here we investigate the trans-Atlantic air traffic for one specific winter day and analyse, which routing changes were required to achieve a reduction in the air traffic’s contribution to climate change. We have applied an atmosphere-chemistry model to calculate so-called five dimensional climate cost functions (CCF), which describe the climate effect of a locally confined emission. The five dimensions r...

  1. Optimal Traffic Allocation for Multi-Stream Aggregation in Heterogeneous Networks

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana; Iversen, Villy Bæk

    2015-01-01

    This paper investigates an optimal traffic rate allocation method for multi-stream aggregation over heterogeneous networks that deals with effective integration of two or more heterogeneous links for improved data throughput and enhanced quality of experience. The heterogeneity and the dynamic...... variations. Furthermore, services with different traffic characteristics in terms of quality of service requirements are considered. The simulation results show the advantages of our scheme with respect to efficient increase in data rate and delay performance compared to traditional schemes....

  2. Channel modeling for fifth generation cellular networks and wireless sensor networks

    Science.gov (United States)

    Torabi, Amir

    In view of exponential growth in data traffic demand, the wireless communications industry has aimed to increase the capacity of existing networks by 1000 times over the next 20 years. A combination of extreme cell densification, more bandwidth, and higher spectral efficiency is needed to support the data traffic requirements for fifth generation (5G) cellular communications. In this research, the potential improvements achieved by using three major 5G enabling technologies (i.e., small cells, millimeter-wave spectrum, and massive MIMO) in rural and urban environments are investigated. This work develops SPM and KA-based ray models to investigate the impact of geometrical parameters on terrain-based multiuser MIMO channel characteristic. Moreover, a new directional 3D channel model is developed for urban millimeter-wave (mmW) small cells. Path-loss, spatial correlation, coverage distance, and coherence length are studied in urban areas. Exploiting physical optics (PO) and geometric optics (GO) solutions, closed form expressions are derived for spatial correlation. Achievable spatial diversity is evaluated using horizontal and vertical linear arrays as well as planar 2D arrays. In another study, a versatile near-ground field prediction model is proposed to facilitate accurate wireless sensor network (WSN) simulations. Monte Carlo simulations are used to investigate the effects of antenna height, frequency of operation, polarization, and terrain dielectric and roughness properties on WSNs performance.

  3. Network Packet Length Covert Channel Based on Empirical Distribution Function

    Directory of Open Access Journals (Sweden)

    Lihua Zhang

    2014-06-01

    Full Text Available Network packet length covert channel modulates secret message bits onto the packet lengths to transmit secret messages. In this paper, a novel network packet length covert channel is proposed. The proposed scheme is based on the empirical distribution function of packet length series of legitimate traffic. Different from the existing schemes, the lengths of packets which are generated by the covert sender follow the distribution of normal traffic more closely in our scheme. To validate the security of the proposed scheme, the state-of-the-art packet length covert channel detection algorithm is adopted. The experimental results show that the packet length covert channel provides a significant performance improvement in detection resistance meanings

  4. Brands & Channels

    Institute of Scientific and Technical Information of China (English)

    Alice Yang

    2009-01-01

    @@ "Brands" and "Channels" are the two most important things in Ku-Hai Chen's eyes when doing business with Main-land China. Ku-Hai Chen, Executive Director of the International Trade Institute of Taiwan External Trade Development Council (TAITRA), flies frequently between Chinese Taipei and Mainland China, and was in Beijing earlier this month for his seminar.

  5. 77 FR 55439 - Vessel Traffic Service Updates, Including Establishment of Vessel Traffic Service Requirements...

    Science.gov (United States)

    2012-09-10

    ... regarding our public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). D. Public... FR 36316, July 15, 1994), the Coast Guard instituted two VTS Special Areas within the VTS Puget Sound... CFR Subpart C was revised and the definitions were moved from 33 CFR 160.203 to 33 CFR 160.204 (68...

  6. Effect of primary user traffic on sensing-throughput tradeoff for cognitive radios

    KAUST Repository

    Tang, Liang

    2011-04-01

    The effect of the primary user traffic on the performance of the secondary network is investigated for the tradeoff between the sensing quality and the achievable throughput. Numerical results show that the actual secondary network performance when the random departure or arrival of the primary user is taken into account is worse than the predicted secondary network performance in the literature assuming constant occupancy state of the primary user. The degree of degradation depends on the traffic intensity as well as the received signal-to-noise ratio at the secondary user. Also, unlike the conventional model where the occupancy state of the primary user is assumed constant, the optimal sensing time in the new model varies for different primary channel conditions when the primary user traffic is considered. © 2011 IEEE.

  7. A possible mechanism for self coordination of bi-directional traffic across nuclear pores

    CERN Document Server

    Kapon, Ruti; Mukamel, David; Reich, and Ziv

    2008-01-01

    Nuclear pore complexes are constantly confronted by large fluxes of macromolecules and macromolecular complexes that need to get into and out of the nucleus. Such bi-directional traffic occurring in a narrow channel can easily lead to jamming. How then is passage between the nucleus and cytoplasm maintained under the varying conditions that arise during the lifetime of the cell? Here, we address this question using computer simulations in which the behaviour of the ensemble of transporting cargoes is analyzed under different conditions. We suggest that traffic can exist in two distinct modes, depending on concentration of cargoes and dissociation rates of the transport receptor-cargo complexes from the pores. In one mode, which prevails when dissociation is quick and cargo concentration is low, transport in either direction proceeds uninterrupted by the other direction. The result is that overall-traffic-direction fluctuates rapidly and unsystematically between import and export. Remarkably, when cargo concen...

  8. Transumo: Toward sustainable and integrated traffic management

    NARCIS (Netherlands)

    Arem, B. van; Pommer, J.

    2009-01-01

    The current and expected increase of traffic demand can not be matched with expansion of road infrastructure. Nor will traditional traffic management measures suffice in the long run. As a consequence we are faced with increasing congestion, an unreliable road network as well as safety and environme

  9. Consistency Analysis of Network Traffic Repositories

    NARCIS (Netherlands)

    Lastdrager, Elmer; Pras, Aiko

    2009-01-01

    Traffic repositories with TCP/IP header information are very important for network analysis. Researchers often assume that such repositories reliably represent all traffic that has been flowing over the network; little thoughts are made regarding the consistency of these repositories. Still, for var

  10. Analysis of urban traffic patterns using clustering

    NARCIS (Netherlands)

    Weijermars, Wilhelmina Adriana Maria

    2007-01-01

    Mobility is still increasing, as are its corresponding negative side effects such as congestion and air pollution. To be able to take adequate measures to minimize these side effects, it is important to obtain insight into the functioning of the traffic system. In common practice, the traffic analys

  11. Women Traffic Officer Project. Final Report.

    Science.gov (United States)

    Department of California Highway Patrol, Sacramento, CA.

    To determine the feasibility of employing women as state traffic officers (STOs), the California Highway Patrol (CHP) conducted a two-year study. The CHP employed forty-one women and forty-two men as traffic officers and gave them the standard sixteen-week training given all new officers. After graduation, the officers were assigned to highway…

  12. Floating car data for traffic monitoring

    DEFF Research Database (Denmark)

    Torp, Kristian; Lahrmann, Harry Spaabæk

    2005-01-01

    This paper describes a complete prototype system that uses Floating Car Data (FCD) for both automatic and manual detection of queues in traffic. The system is developed under EU’s Tempo program. The systems consists of small hardware units placed in mobile traffic report units (we use taxis...

  13. An analysis of the traffic safety phenomenon.

    NARCIS (Netherlands)

    Asmussen, E. & Kranenburg, A.

    1982-01-01

    The lack of traffic safety is a combination of the critical coincidence of circumstances in the traffic of incidents (near-accidents) and accidents with unwanted (permanent) consequences, such as fatalities, injured and disabled persons and material damage. This definition covers the whole of the cr

  14. SIMPLE LATTICE BOLTZMANN MODEL FOR TRAFFIC FLOWS

    Institute of Scientific and Technical Information of China (English)

    Yan Guangwu; Hu Shouxin

    2000-01-01

    A lattice Boltzmann model with 5-bit lattice for traffic flows is proposed.Using the Chapman-Enskog expansion and multi-scale technique,we obtain the higher-order moments of equilibrium distribution function.A simple traffic light problem is simulated by using the present lattice Boltzmann model,and the result agrees well with analytical solution.

  15. Traffic Light Detection Using Conic Section Geometry

    Science.gov (United States)

    Hosseinyalmdary, S.; Yilmaz, A.

    2016-06-01

    Traffic lights detection and their state recognition is a crucial task that autonomous vehicles must reliably fulfill. Despite scientific endeavors, it still is an open problem due to the variations of traffic lights and their perception in image form. Unlike previous studies, this paper investigates the use of inaccurate and publicly available GIS databases such as OpenStreetMap. In addition, we are the first to exploit conic section geometry to improve the shape cue of the traffic lights in images. Conic section also enables us to estimate the pose of the traffic lights with respect to the camera. Our approach can detect multiple traffic lights in the scene, it also is able to detect the traffic lights in the absence of prior knowledge, and detect the traffics lights as far as 70 meters. The proposed approach has been evaluated for different scenarios and the results show that the use of stereo cameras significantly improves the accuracy of the traffic lights detection and pose estimation.

  16. Calculating Traffic based on Road Sensor Data

    NARCIS (Netherlands)

    Bisseling, Rob; Gao, Fengnan; Hafkenscheid, Patrick; Idema, Reijer; Jetka, Tomasz; Guerra Ones, Valia; Sikora, Monika

    2014-01-01

    Road sensors gather a lot of statistical data about traffic. In this paper, we discuss how a measure for the amount of traffic on the roads can be derived from this data, such that the measure is independent of the number and placement of sensors, and the calculations can be performed quickly for la

  17. Border Effects in Passenger Air Traffic

    OpenAIRE

    Klodt, Henning

    2003-01-01

    National borders substantially matter in passenger air traffic. Empirical estimates based upon a new data set on domestic and international departures from German airports indicate that the German border reduces air traffic activity by a factor of four to five. This result adds a further piece of evidence to the significance of border effects in various kinds of economic activity.

  18. Road traffic emission monitoring on motorways

    NARCIS (Netherlands)

    Dittrich, M.G.; Beek, P.J.G. van

    2006-01-01

    Road traffic noise is one of the major environmental noise sources that is known to cause health problems. Despite existing noise reception items, the continuing growth of traffic causes higher levels than the lims allow. Consequently, excessive costs are incurred for noise barriers along roads and

  19. Statistical Physics Algorithms for Traffic Reconstruction

    OpenAIRE

    De La Fortelle, Arnaud; Lasgouttes, Jean-Marc; Furtlehner, Cyril

    2007-01-01

    Concepts and techniques from statistical physics inspired a new method for traffic prediction. This method is particularly suitable in settings where the only information available is floating car data. We propose a system, based on the Ising model of statistical physics, which both reconstructs and predicts the traffic in real time using a message-passing algorithm.

  20. Survivable Impairment-Aware Traffic Grooming

    NARCIS (Netherlands)

    Beshir, A.; Nuijts, R.; Malhotra, R.; Kuipers, F.

    2011-01-01

    Traffic grooming allows efficient utilization of network capacity by aggregating several independent traffic streams into a wavelength. In addition, survivability and impairment-awareness (i.e., taking into account the effect of physical impairments) are two important issues that have gained a lot o

  1. GPS queues with heterogeneous traffic classes

    NARCIS (Netherlands)

    Borst, Sem; Mandjes, Michel; Uitert, van Miranda

    2002-01-01

    We consider a queue fed by a mixture of light-tailed and heavy-tailed traffic. The two traffic classes are served in accordance with the generalized processor sharing (GPS) discipline. GPS-based scheduling algorithms, such as weighted fair queueing (WFQ), have emerged as an important mechanism for a

  2. Epidemiology of deaths due to traffic accidents in Kermanshah province (2012

    Directory of Open Access Journals (Sweden)

    Azam Malekifar

    2016-01-01

    Full Text Available Background: The increasing trend of traffic accidents is one of the most serious problems of public health. The aim of this paper was to investigate the fatal traffic accidents in Kermanshah province. Method: All research data required were obtained from Legal Medicine Organization and analyzed by Stata-11 software. Traffic statistics available on the Road Maintenance and Transportation Organization website were used to study the death rate per month and day according to traffic level on suburban highways. Results: The incidence rate of age-standardized deaths due to road traffic accidents was 26.1per 100,000 people, and the mean age of the dead was 39.98±21.60 years. The mortality rate was higher in men, those more than 40 years old, married, illiterate and self-employed. Considering the traffic rate on suburban roads, the highest death rate occurred in the warmest months of the year during the day. Furthermore, most deaths were due to collisions and the highest frequency of death was reported for the car occupants. In most cases, head injuries and head traumas were the final cause of death. A significant correlation was reported between the type of vehicle and the cause of death and how the accident occurred (P<0.05. Conclusion: The mortality rate due to traffic accidents in Kermanshah province is high. Surveillance over the suburban roads in hot seasons and male drivers is of particular importance.

  3. ACCOUNT OF ROAD CONDITIONS WHILE INVESTIGATING TRAFFIC ACCIDENTS

    OpenAIRE

    D. D. Selioukov; I. I. Leonovich

    2014-01-01

    The paper considers problems on better traffic safety at government, authority, engineering and driver activity levels, account of road conditions while investigating traffic accidents. The paper also provides road defects mentioned in forensic transport examinations of traffic accidents.

  4. Modeling Network Traffic in Wavelet Domain

    Directory of Open Access Journals (Sweden)

    Sheng Ma

    2004-12-01

    Full Text Available This work discovers that although network traffic has the complicated short- and long-range temporal dependence, the corresponding wavelet coefficients are no longer long-range dependent. Therefore, a "short-range" dependent process can be used to model network traffic in the wavelet domain. Both independent and Markov models are investigated. Theoretical analysis shows that the independent wavelet model is sufficiently accurate in terms of the buffer overflow probability for Fractional Gaussian Noise traffic. Any model, which captures additional correlations in the wavelet domain, only improves the performance marginally. The independent wavelet model is then used as a unified approach to model network traffic including VBR MPEG video and Ethernet data. The computational complexity is O(N for developing such wavelet models and generating synthesized traffic of length N, which is among the lowest attained.

  5. Intelligent Model for Traffic Safety Applications

    Directory of Open Access Journals (Sweden)

    C. Chellappan

    2012-01-01

    Full Text Available Problem statement: This study presents an analysis on road traffic system focused on the use of communications to detect dangerous vehicles on roads and highways and how it could be used to enhance driver safety. Approach: The intelligent traffic safety application model is based on all traffic flow theories developed in the last years, leading to reliable representations of road traffic, which is of major importance in achieving the attenuation of traffic problems. The model also includes the decision making process from the driver in accelerating, decelerating and changing lanes. Results: The individuality of each of these processes appears from the model parameters that are randomly generated from statistical distributions introduced as input parameters. Conclusion: This allows the integration of the individuality factor of the population elements yielding knowledge on various driving modes at wide variety of situations.

  6. Distributed traffic signal control using fuzzy logic

    Science.gov (United States)

    Chiu, Stephen

    1992-01-01

    We present a distributed approach to traffic signal control, where the signal timing parameters at a given intersection are adjusted as functions of the local traffic condition and of the signal timing parameters at adjacent intersections. Thus, the signal timing parameters evolve dynamically using only local information to improve traffic flow. This distributed approach provides for a fault-tolerant, highly responsive traffic management system. The signal timing at an intersection is defined by three parameters: cycle time, phase split, and offset. We use fuzzy decision rules to adjust these three parameters based only on local information. The amount of change in the timing parameters during each cycle is limited to a small fraction of the current parameters to ensure smooth transition. We show the effectiveness of this method through simulation of the traffic flow in a network of controlled intersections.

  7. [Clinical examinations for the traffic accident patients].

    Science.gov (United States)

    Hitosugi, Masahito

    2008-11-30

    Traffic accident is a leading cause of unintentional death and about six-thousands annually died in Japan. As about one-million of persons suffer from traffic injuries, most of them seek medical attention. Therefore, medical staffs have to find the injuries accurately and treat immediately. Furthermore, the cause of accident should also be considered; why the accident was occurred, human error of the driver? To solve these problems, clinical examinations were needed. Medical staffs have to understand the characteristics of the traffic injuries: severe and multiple blunt injuries, popular injuries can be estimated with considering the pattern of the accident. Because some of the accidents are occurred when the driver is under the influence of alcohol and other drugs, screening of these subjects should be performed. Because the public is largely unaware of the preventable nature of traffic injuries, in addition to diagnose and treat accurately, we medical staffs have to attend on the primary prevention of the traffic injuries.

  8. The Analysis of Rail Traffic Control Systems

    Directory of Open Access Journals (Sweden)

    Darius Gaidelis

    2011-04-01

    Full Text Available The systems used for rail traffic control are compared. Their advantages and disadvantages are analysed. The present and future development of rail traffic control systems in various countries is considered. The possibility of adapting these microprocessor-based traffic control systems to the conditions of Lithuania is analysed. For this purpose, the analysis of goods transported by Lithuanian railways is made, and the non-uniform amount of goods transported on different road sections is evaluated. The number of the delayed trains due to the failure of traffic control systems in recent years is determined, the cost of installing a new microprocessor-based traffic control system at the railway station, as well as its repay time and the demand for employees are calculated. Article in Lithuanian

  9. Traffic flow dynamics data, models and simulation

    CERN Document Server

    Treiber, Martin

    2013-01-01

    This textbook provides a comprehensive and instructive coverage of vehicular traffic flow dynamics and modeling. It makes this fascinating interdisciplinary topic, which to date was only documented in parts by specialized monographs, accessible to a broad readership. Numerous figures and problems with solutions help the reader to quickly understand and practice the presented concepts. This book is targeted at students of physics and traffic engineering and, more generally, also at students and professionals in computer science, mathematics, and interdisciplinary topics. It also offers material for project work in programming and simulation at college and university level. The main part, after presenting different categories of traffic data, is devoted to a mathematical description of the dynamics of traffic flow, covering macroscopic models which describe traffic in terms of density, as well as microscopic many-particle models in which each particle corresponds to a vehicle and its driver. Focus chapters on ...

  10. Traffic congestion in interconnected complex networks

    CERN Document Server

    Tan, Fei; Xia, Yongxiang; Tse, Chi K

    2014-01-01

    Traffic congestion in isolated complex networks has been investigated extensively over the last decade. Coupled network models have recently been developed to facilitate further understanding of real complex systems. Analysis of traffic congestion in coupled complex networks, however, is yet to come. In this paper, we try to explore the effect of interconnections on traffic congestion in interconnected BA scale-free networks. We find that assortative coupling can alleviate traffic congestion better than disassortative and random coupling when the node processing capacity is allocated based on node usage probability. Furthermore, the optimal coupling probability can be found for assortative coupling. However, three types of coupling preferences achieve similar traffic performance if all nodes share the same processing capacity. We analyze interconnected Internet AS-level graphs of Japan and South Korea and obtain similar results. Some practical suggestions are presented to optimize such real-world interconnect...

  11. Traffic and Granular Flow ’03

    CERN Document Server

    Luding, Stefan; Bovy, Piet; Schreckenberg, Michael; Wolf, Dietrich

    2005-01-01

    These proceedings are the fifth in the series Traffic and Granular Flow, and we hope they will be as useful a reference as their predecessors. Both the realistic modelling of granular media and traffic flow present important challenges at the borderline between physics and engineering, and enormous progress has been made since 1995, when this series started. Still the research on these topics is thriving, so that this book again contains many new results. Some highlights addressed at this conference were the influence of long range electric and magnetic forces and ambient fluids on granular media, new precise traffic measurements, and experiments on the complex decision making of drivers. No doubt the “hot topics” addressed in granular matter research have diverged from those in traffic since the days when the obvious analogies between traffic jams on highways and dissipative clustering in granular flow intrigued both c- munities alike. However, now just this diversity became a stimulating feature of the ...

  12. A traffic-depended multi-buffer node architecture and an effective access technique under symmetric and asymmetric IP traffic scenarios for unslotted ring WDM MANs

    Science.gov (United States)

    Baziana, Peristera A.

    2016-09-01

    This study aims to put forward an extensive discussion about the increasing demand for available bandwidth to serve the multiple types of traffic in modern wavelength division multiplexing (WDM) metropolitan area networks (MANs). A traffic-depended multi-buffer node architecture in conjunction with an efficient asynchronous transmission WDM access (WDMA) protocol to serve the variable size Internet packets in ring MANs is proposed. The structure of the multi-buffer node architecture is determined by the probability distribution of each packet size category in the MAN traffic, providing storage and dropping events equity among the nodes. The adopted WDMA algorithm satisfies the requirement for high performance efficiency especially under high offered load, by taking care to optimally face the bandwidth fragmentation problem and to maximize the bandwidth exploitation, while it effectively avoids both the packets collisions over the wavelengths and the destination conflicts. Numerical results prove that the proposed network model achieves throughput improvement up to 334% as compared with the relative study of Pranggono and Elmirghani (2011). An analytical framework is developed for the protocol throughput predictions under both symmetric and asymmetric IP traffic scenarios. Also, the proposed protocol performance is thoroughly investigated through simulation results based on Poisson and self-similar traffic model statistics, for both traffic scenarios.

  13. MEMS in microfluidic channels.

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, Carol Iris Hill; Okandan, Murat; Michalske, Terry A.; Sounart, Thomas L.; Matzke, Carolyn M.

    2004-03-01

    Microelectromechanical systems (MEMS) comprise a new class of devices that include various forms of sensors and actuators. Recent studies have shown that microscale cantilever structures are able to detect a wide range of chemicals, biomolecules or even single bacterial cells. In this approach, cantilever deflection replaces optical fluorescence detection thereby eliminating complex chemical tagging steps that are difficult to achieve with chip-based architectures. A key challenge to utilizing this new detection scheme is the incorporation of functionalized MEMS structures within complex microfluidic channel architectures. The ability to accomplish this integration is currently limited by the processing approaches used to seal lids on pre-etched microfluidic channels. This report describes Sandia's first construction of MEMS instrumented microfluidic chips, which were fabricated by combining our leading capabilities in MEMS processing with our low-temperature photolithographic method for fabricating microfluidic channels. We have explored in-situ cantilevers and other similar passive MEMS devices as a new approach to directly sense fluid transport, and have successfully monitored local flow rates and viscosities within microfluidic channels. Actuated MEMS structures have also been incorporated into microfluidic channels, and the electrical requirements for actuation in liquids have been quantified with an elegant theory. Electrostatic actuation in water has been accomplished, and a novel technique for monitoring local electrical conductivities has been invented.

  14. Hardware simulation of a multi-processor system for measuring road traffic parameters in real-time

    International Nuclear Information System (INIS)

    The real-time measurement and analysis of various road traffic parameters such as volume, speed and head ways are increasingly required for traffic control and management. Image processing technique is now considered as an attractive and flexible technique for automatic analysis and data collection in traffic engineering. The computational requirements in real-time image processing applications, such as road traffic, is beyond the capacity of conventional computers, therefore, most systems built/designed for this purpose usually use multi-processor systems. As the complexity and sophistication of modern multi-processor systems are very high and still increasing, it becomes essential to simulate the system before building it, in order to detect errors, measure its performance and find ways to improve it. In this paper design, modeling, hardware simulation and results of a multi-microprocessor system for measuring road traffic parameters in real-time are presented. (author)

  15. Traffic engineering in ambient networks: challenges and approaches

    OpenAIRE

    Abrahamsson, Henrik; Gunnar, Anders

    2004-01-01

    The focus of this paper is on traffic engineering in ambient networks. We describe and categorize different alternatives for making the routing more adaptive to the current traffic situation and discuss the challenges that ambient networks pose on traffic engineering methods. One of the main objectives of traffic engineering is to avoid congestion by controlling and optimising the routing function, or in short, to put the traffic where the capacity is. The main challenge for traffic engin...

  16. Winning strategies in congested traffic

    CERN Document Server

    Jarai-Szabo, Ferenc

    2012-01-01

    One-directional traffic on two-lanes is modeled in the framework of a spring-block type model. A fraction $q$ of the cars are allowed to change lanes, following simple dynamical rules, while the other cars keep their initial lane. The advance of cars, starting from equivalent positions and following the two driving strategies is studied and compared. As a function of the parameter $q$ the winning probability and the average gain in the advancement for the lane-changing strategy is computed. An interesting phase-transition like behavior is revealed and conclusions are drawn regarding the conditions when the lane changing strategy is the better option for the drivers.

  17. Traffic Dynamics of Computer Networks

    Science.gov (United States)

    Fekete, Attila

    2008-10-01

    Two important aspects of the Internet, namely the properties of its topology and the characteristics of its data traffic, have attracted growing attention of the physics community. My thesis has considered problems of both aspects. First I studied the stochastic behavior of TCP, the primary algorithm governing traffic in the current Internet, in an elementary network scenario consisting of a standalone infinite-sized buffer and an access link. The effect of the fast recovery and fast retransmission (FR/FR) algorithms is also considered. I showed that my model can be extended further to involve the effect of link propagation delay, characteristic of WAN. I continued my thesis with the investigation of finite-sized semi-bottleneck buffers, where packets can be dropped not only at the link, but also at the buffer. I demonstrated that the behavior of the system depends only on a certain combination of the parameters. Moreover, an analytic formula was derived that gives the ratio of packet loss rate at the buffer to the total packet loss rate. This formula makes it possible to treat buffer-losses as if they were link-losses. Finally, I studied computer networks from a structural perspective. I demonstrated through fluid simulations that the distribution of resources, specifically the link bandwidth, has a serious impact on the global performance of the network. Then I analyzed the distribution of edge betweenness in a growing scale-free tree under the condition that a local property, the in-degree of the "younger" node of an arbitrary edge, is known in order to find an optimum distribution of link capacity. The derived formula is exact even for finite-sized networks. I also calculated the conditional expectation of edge betweenness, rescaled for infinite networks.

  18. Performance evaluation and traffic modeling

    NARCIS (Netherlands)

    Berg, J.L. van den; Bohnert, T.M.; Cabral, O.; Moltchanov, D.; Staehle, D.; Velez, F.

    2009-01-01

    Mobile and wireless communication systems are becoming more and more complex, making understanding the interaction of different technologies on different layers a very difficult task. The introduction of sophisticated techniques on the physical layer that react to changes of the wireless channel on

  19. Efficient Traffic Control of VoD System

    CERN Document Server

    Kanrar, Soumen

    2011-01-01

    It has been a challenging issue to provide digital quality multimedia data stream to the remote user through the distributed system. The main aspects to design the real distributed system, which reduce the cost of the network by means of reduce packet loss and enhanced over all system performance. Since the number of user increased rapidly in the network it posed heavy load to the video servers. The requested clients, servers are all distributed in nature and the data stream delivered to the user without error. In this work I have presented the performance of the video on demand server by efficient traffic control at real time with respect to incoming multirate traffic pattern . In this work, I present how the overall system performance gradually decreases when the client population sized in the clusters increase. This work indicated the load balancing required for the on demand video distributed system to provide efficient cost effective service to the local or remote clients.

  20. Quality function deployment applied to local traffic accident reduction.

    Science.gov (United States)

    Sohn, S Y

    1999-11-01

    One of the major tasks of police stations is the management of local road traffic accidents. Proper prevention policy which reflects the local accident characteristics could immensely help individual police stations in decreasing various severity levels of road traffic accidents. In order to relate accident variation to local driving environmental characteristics, we use both cluster analysis and Poisson regression. The fitted result at the level of each cluster for each type of accident severity is utilized as an input to quality function deployment. Quality function deployment (QFD) has been applied to customer satisfaction in various industrial quality improvement settings, where several types of customer requirements are related to various control factors. We show how QFD enables one to set priorities on various road accident control policies to which each police station has to pay particular attention.

  1. Monitoring information model for traffic engineering over MPLS VPNs

    Science.gov (United States)

    Cherkaoui, Omar; Sarrazin, Alain; Francoeur, Guy; Chen, Ken

    2001-07-01

    Monitoring is the part of Traffic Engineering (TE) that aims at optimizing the use of network resources and assists both in informing the provider and proving to the customer that the service offered respects the SLAs required to optimize the network resources utilization. In this paper, we present a monitoring framework for MPLS-VPN services. We first briefly review MPLS, VPN, NBVPN, Constrained Based Routing to provide a background for the discussion of traffic Engineering. We then discuss the general issues surrounding the design of a MPLS VPN from the point of view of TE and go on to present a management framework that extends the DEN information specific to MPLS VPNs. In this framework, we add policy actions that react dynamically to abnormal results by changing the sampling frequency.

  2. Efficient Traffic Control of VoD System

    Directory of Open Access Journals (Sweden)

    Soumen kanrar

    2011-10-01

    Full Text Available It has been a challenging issue to provide digital quality multimedia data stream to the remote user through the distributed system. The main aspects to design the real distributed system, which reduce the cost of the network by means of reduce packet loss and enhanced over all system performance. Since thenumber of user increased rapidly in the network it posed heavy load to the video servers. The requested clients, servers are all distributed in nature and the data stream delivered to the user without error. In this work I have presented the performance of the video on demand server by efficient traffic control at real time with respect to incoming multirate traffic pattern . In this work, I present how the overall system performance gradually decreases when the client population sized in the clusters increase. Thiswork indicated the load balancing required for the on demand video distributed system to provide efficient cost effective service to the local or remote clients.

  3. Drawing for Traffic Marking Using Bidirectional Gradient-Based Detection with MMS LIDAR Intensity

    Science.gov (United States)

    Takahashi, G.; Takeda, H.; Nakamura, K.

    2016-06-01

    Recently, the development of autonomous cars is accelerating on the integration of highly advanced artificial intelligence, which increases demand for a digital map with high accuracy. In particular, traffic markings are required to be precisely digitized since automatic driving utilizes them for position detection. To draw traffic markings, we benefit from Mobile Mapping Systems (MMS) equipped with high-density Laser imaging Detection and Ranging (LiDAR) scanners, which produces large amount of data efficiently with XYZ coordination along with reflectance intensity. Digitizing this data, on the other hand, conventionally has been dependent on human operation, which thus suffers from human errors, subjectivity errors, and low reproductivity. We have tackled this problem by means of automatic extraction of traffic marking, which partially accomplished to draw several traffic markings (G. Takahashi et al., 2014). The key idea of the method was extracting lines using the Hough transform strategically focused on changes in local reflection intensity along scan lines. However, it failed to extract traffic markings properly in a densely marked area, especially when local changing points are close each other. In this paper, we propose a bidirectional gradient-based detection method where local changing points are labelled with plus or minus group. Given that each label corresponds to the boundary between traffic markings and background, we can identify traffic markings explicitly, meaning traffic lines are differentiated correctly by the proposed method. As such, our automated method, a highly accurate and non-human-operator-dependent method using bidirectional gradient-based algorithm, can successfully extract traffic lines composed of complex shapes such as a cross walk, resulting in minimizing cost and obtaining highly accurate results.

  4. DRAWING FOR TRAFFIC MARKING USING BIDIRECTIONAL GRADIENT-BASED DETECTION WITH MMS LIDAR INTENSITY

    Directory of Open Access Journals (Sweden)

    G. Takahashi

    2016-06-01

    Full Text Available Recently, the development of autonomous cars is accelerating on the integration of highly advanced artificial intelligence, which increases demand for a digital map with high accuracy. In particular, traffic markings are required to be precisely digitized since automatic driving utilizes them for position detection. To draw traffic markings, we benefit from Mobile Mapping Systems (MMS equipped with high-density Laser imaging Detection and Ranging (LiDAR scanners, which produces large amount of data efficiently with XYZ coordination along with reflectance intensity. Digitizing this data, on the other hand, conventionally has been dependent on human operation, which thus suffers from human errors, subjectivity errors, and low reproductivity. We have tackled this problem by means of automatic extraction of traffic marking, which partially accomplished to draw several traffic markings (G. Takahashi et al., 2014. The key idea of the method was extracting lines using the Hough transform strategically focused on changes in local reflection intensity along scan lines. However, it failed to extract traffic markings properly in a densely marked area, especially when local changing points are close each other. In this paper, we propose a bidirectional gradient-based detection method where local changing points are labelled with plus or minus group. Given that each label corresponds to the boundary between traffic markings and background, we can identify traffic markings explicitly, meaning traffic lines are differentiated correctly by the proposed method. As such, our automated method, a highly accurate and non-human-operator-dependent method using bidirectional gradient-based algorithm, can successfully extract traffic lines composed of complex shapes such as a cross walk, resulting in minimizing cost and obtaining highly accurate results.

  5. Mechanosensitive Channels: In Touch with Piezo

    OpenAIRE

    Xiao, Rui; Xu, X. Z. Shawn

    2010-01-01

    Mechanosensory transduction underlies touch, hearing and proprioception and requires mechanosensitive channels that are directly gated by forces; however, the molecular identities of these channels remain largely elusive. A new study has identified Piezo1 and Piezo2 as a novel class of mechanosensitive channels.

  6. Auto-Mobile Vehicle Direction in Road Traffic using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    M.Rathinakumar

    2013-07-01

    Full Text Available So far Most of the current work on this area dealswith traffic volume prediction during peak hours and thereasons behind accidents only. This work presents the analysis of automobile vehicle directing in varioustraffic flow conditions using Artificial neural network architecture. Now a days, due to unprecedentedincrease in automobile vehicular traffic especiallyin metro-Politian cities, it has become highly imperativethat we must choose an optimum road route in accordance with our requirements. The requirements are :volume of the traffic, Distance between source anddestination, no of signals in between the source anddestination, the nature of the road condition , fuel consumption and Travel Timing. Artificial Neuralnetworks, a soft computing technique, modeled afterbrain biological neuron functioning, helps to obtainthe required road way or route as per the traininggiven to it. Here we make use of Back propagationnetwork, which changes the weights value of the hidden layers, thereby activation function value whichfires the neuron to get the required output.

  7. The Stability of Multi-modal Traffic Network

    Science.gov (United States)

    Han, Ling-Hui; Sun, Hui-Jun; Zhu, Cheng-Juan; Wu, Jian-Jun; Jia, Bin

    2013-07-01

    There is an explicit and implicit assumption in multimodal traffic equilibrium models, that is, if the equilibrium exists, then it will also occur. The assumption is very idealized; in fact, it may be shown that the quite contrary could happen, because in multimodal traffic network, especially in mixed traffic conditions the interaction among traffic modes is asymmetric and the asymmetric interaction may result in the instability of traffic system. In this paper, to study the stability of multimodal traffic system, we respectively present the travel cost function in mixed traffic conditions and in traffic network with dedicated bus lanes. Based on a day-to-day dynamical model, we study the evolution of daily route choice of travelers in multimodal traffic network using 10000 random initial values for different cases. From the results of simulation, it can be concluded that the asymmetric interaction between the cars and buses in mixed traffic conditions can lead the traffic system to instability when traffic demand is larger. We also study the effect of travelers' perception error on the stability of multimodal traffic network. Although the larger perception error can alleviate the effect of interaction between cars and buses and improve the stability of traffic system in mixed traffic conditions, the traffic system also become instable when the traffic demand is larger than a number. For all cases simulated in this study, with the same parameters, traffic system with dedicated bus lane has better stability for traffic demand than that in mixed traffic conditions. We also find that the network with dedicated bus lane has higher portion of travelers by bus than it of mixed traffic network. So it can be concluded that building dedicated bus lane can improve the stability of traffic system and attract more travelers to choose bus reducing the traffic congestion.

  8. The Stability of Multi-modal Traffic Network

    Institute of Scientific and Technical Information of China (English)

    HAN Ling-Hui; Sun Hui-Jun; ZHU Cheng-Juan; WU Jian-Jun; JIA Bin

    2013-01-01

    There is an explicit and implicit assumption in multimodal traffic equilibrium models,that is,if the equilibrium exists,then it will also occur.The assumption is very idealized; in fact,it may be shown that the quite contrary could happen,because in multimodal traffic network,especially in mixed traffic conditions the interaction among traffic modes is asymmetric and the asymmetric interaction may result in the instability of traffic system.In this paper,to study the stability of multimodal traffic system,we respectively present the travel cost function in mixed traffic conditions and in traffic network with dedicated bus lanes.Based on a day-to-day dynamical model,we study the evolution of daily route choice of travelers in multimodal traffic network using 10000 random initial values for different cases.From the results of simulation,it can be concluded that the asymmetric interaction between the cars and buses in mixed traffic conditions can lead the traffic system to instability when traffic demand is larger.We also study the effect of travelers' perception error on the stability of multimodal traffic network.Although the larger perception error can alleviate the effect of interaction between cars and buses and improve the stability of traffic system in mixed traffic conditions,the traffic system also become instable when the traffic demand is larger than a number.For all cases simulated in this study,with the same parameters,traffic system with dedicated bus lane has better stability for traffic demand than that in mixed traffic conditions.We also find that the network with dedicated bus lane has higher portion of travelers by bus than it of mixed traffic network.So it can be concluded that building dedicated bus lane can improve the stability of traffic system and attract more travelers to choose bus reducing the traffic congestion.

  9. Performance Analysis of Mobile WiMAX System using Turbo Coding Technique for Different Modulation Schemes under AWGN and Rayleigh Channel

    Directory of Open Access Journals (Sweden)

    P. Samundiswary

    2013-02-01

    Full Text Available In wireless communication, future demands must be met using more data throughput wireless technologies. Since bandwidth is limited and user demand continues to grow. This problem could be solved by WiMAX technology based on IEEE 802.16e specifications, which provides high data services on mobile environment. So, to support high data rate traffic, the error correction could be enhanced by incorporating a better channel coding technique in mobile WiMAX physical layer. Further, coding technique is used for providing reliable information through the transmission channel to the user. It is used to reduce the level of noise and interferences in electronic medium. The amount of error detection and correction required and its effectiveness depends on the signal to noise ratio. The advantages of Forward Error Correction (FEC are that a back-channel is not required, or that retransmission of data can often be avoided, at the cost of higher bandwidth requirements on average. In this paper, the performance of mobile WiMAX system with convolutional turbo coding is determined and analyzed for various modulation schemes under different channels. The BER performance of mobile WiMAX system using convolutional turbo Coding is determined and compared with the existing concatenated Reed Solomon(RS coding in the presence of AWGN and Rayleigh Channel. From the simulation results, it is verified that convolutional turbo coding provides better BER performance than concatenated RS coding

  10. Physics of Traffic and the Crowds Theory: AMultidisciplinary Approach to Mobility Education

    Institute of Scientific and Technical Information of China (English)

    Laura Tamburini[1,2; Sabrina Colomban[3

    2015-01-01

    Crowding is a reality in which we find ourselves involved daily. The crowd produced in a traffic jam is a dynamic entity inwhich the application of physics, mathematics and biology can provide practical help to understand how and why this problematicsituation occurs and what solutions can be found to resolve it. In the mobility education project "SicuraMENTE", we carried out anexperiment on the conduct of a crowd by simulating a situation of intense city traffic. Taking a cue from an experimental situationproposed in traffic physics, we have verified that a route with limited access can generate a traffic jam and the crowd of pedestrianscan be mitigated by forcing the crowd to use dedicated streets. Taking the outgoing time of the student crowd from the outlet road,with and without the presence of an obstacle in the middle of the roadway, it was found that the traffic jam is resolved more quicklyin the situation with an obstacle because the flow of people is divided into two separate channels, reducing the probability that twoindividuals are close and that this creates an obstruction (example of counter-intuitive physical principle). We also verified that thespeed of the elements of the crowd influences the formation of traffic jams, which are on average more likely in the case of higherspeed. These important aspects in the design of road networks and transport infrastructure have made students reason on physics'topics, but also on the correct conduct in traffic. The multidisciplinary approach in education for safe and sustainable mobility, soinnovative in Italy, turned out to be effective in terms of teaching in the frame of a mix of academic disciplines, in which road safetyeducation has become the context and the goal.

  11. Modeling Traffic Flow and Management at Un-signalized, Signalized and Roundabout Road Intersections

    Directory of Open Access Journals (Sweden)

    R. Kakooza

    2005-01-01

    Full Text Available Traffic congestion continues to hinder economic and social development and also has a negative impact on the environment. A simple mathematical model is used to analyze the different types of road intersections in terms of their Performance in relation to managing traffic congestion and to establish the condition for stability of the road intersections after sufficiently longer periods of time (steady-state. In the analysis, single and double lane un-signalized, signalized and roundabout intersections are evaluated on the basis of their performance (expected number of vehicles and waiting time. Experimental scenarios are carefully designed to analyze the performance of the different types of intersections. It is noted that under light traffic, roundabout intersections perform better than un-signalized and signalized in terms of easing congestion. However under heavy traffic, signalized intersection perform better in terms of easing traffic congestion compared to un-signalized and roundabout intersections. It is further noted that for stability of a road intersection, the proportion of the time a road link stopping at an intersection is delayed should not exceed the utilization factor (the ratio of the arrival rate of vehicles to the product of number of service channels and service rate.

  12. Fixed channel assignment in cellular communication systems considering the whole set of packed patterns

    DEFF Research Database (Denmark)

    Borges, Pedro Manuel F. C.; Vidal, Rene Victor Valqui

    2000-01-01

    This paper addresses the problem of fixed channel assignment in cellular communication systems with nonuniform traffic distribution. The objective of the channel assignment is to minimise the average blocking probability. Methods for finding a good allocation can be based on first building a numb...

  13. Strategies for prevention of road traffic injuries (RTIs) in Pakistan: situational analysis.

    Science.gov (United States)

    Khan, Adeel Ahmed; Fatmi, Zafar

    2014-05-01

    Road traffic injuries (RTIs) are one of the leading causes of death among productive age group. Using systems approach framework (SAF), current preventive strategies for RTI control were reviewed in Pakistan. A review of the literature was done using four international search engines. Only ten studies on preventive strategies for RTI stemming from Pakistan were found. The first Road Traffic Injuries Research Network (RTIRN) surveillance system for road traffic injuries was established in urban city (Karachi) in Pakistan has shown promise for injury control and should be scaled up to other cities. Enforcement of traffic laws on seat-belt and helmet wearing is poor. National Highway and Motorway Police Ordinance (2000) was one of the few legislative measure so far taken in Pakistan. Using SAF, efforts are required to implement interventions targeting human, vehicle design and also making environment safer for road users.

  14. What Can Wireless Cellular Technologies Do about the Upcoming Smart Metering Traffic?

    DEFF Research Database (Denmark)

    Nielsen, Jimmy Jessen; Madueño, Germán Corrales; Pratas, Nuno;

    2015-01-01

    The introduction of smart electricity meters with cellular radio interface puts an additional load on the wireless cellular networks. Currently, these meters are designed for low duty cycle billing and occasional system check, which generates a low-rate sporadic traffic. As the number of...... higher rates per device. In this paper, we characterize the current traffic generated by smart electricity meters and supplement it with the potential traffic requirements brought by introducing enhanced Smart Meters, i.e., meters with PMU-like capabilities. Our study shows how GSM/GPRS and LTE cellular...... system performance behaves with the current and next generation smart meters traffic, where it is clearly seen that the PMU data will seriously challenge these wireless systems. We conclude by highlighting the possible solutions for upgrading the cellular standards, in order to cope with the upcoming...

  15. Intra-City Urban Network and Traffic Flow Analysis from GPS Mobility Trace

    CERN Document Server

    Leung, Ian X Y; Hui, Pan; Lio', Pietro

    2011-01-01

    We analyse two large-scale intra-city urban networks and traffic flows therein measured by GPS traces of taxis in San Francisco and Shanghai. Our results coincide with previous findings that, based purely on topological means, it is often insufficient to characterise traffic flow. Traditional shortest-path betweenness analysis, where shortest paths are calculated from each pairs of nodes, carries an unrealistic implicit assumption that each node or junction in the urban network generates and attracts an equal amount of traffic. We also argue that weighting edges based only on euclidean distance is inadequate, as primary roads are commonly favoured over secondary roads due to the perceived and actual travel time required. We show that betweenness traffic analysis can be improved by a simple extended framework which incorporates both the notions of node weights and fastest-path betweenness. We demonstrate that the framework is superior to traditional methods based solely on simple topological perspectives.

  16. A critical review of principal traffic noise models: Strategies and implications

    International Nuclear Information System (INIS)

    The paper presents an exhaustive comparison of principal traffic noise models adopted in recent years in developed nations. The comparison is drawn on the basis of technical attributes including source modelling and sound propagation algorithms. Although the characterization of source in terms of rolling and propulsion noise in conjunction with advanced numerical methods for sound propagation has significantly reduced the uncertainty in traffic noise predictions, the approach followed is quite complex and requires specialized mathematical skills for predictions which is sometimes quite cumbersome for town planners. Also, it is sometimes difficult to follow the best approach when a variety of solutions have been proposed. This paper critically reviews all these aspects pertaining to the recent models developed and adapted in some countries and also discusses the strategies followed and implications of these models. - Highlights: • Principal traffic noise models developed are reviewed. • Sound propagation algorithms used in traffic noise models are compared. • Implications of models are discussed

  17. Partial QoS-Aware Opportunistic Relay Selection Over Two-Hop Channels: End-to-End Performance Under Spectrum-Sharing Requirements

    KAUST Repository

    Yuli Yang,

    2014-10-01

    In this paper, we propose a partial quality-of-service (QoS)-oriented relay selection scheme with a decode-and-forward (DF) relaying protocol, to reduce the feedback amount required for relay selection. In the proposed scheme, the activated relay is the one with the maximum signal-to-noise power ratio (SNR) in the second hop among those whose packet loss rates (PLRs) in the first hop achieve a predetermined QoS level. For the purpose of evaluating the performance of the proposed scheme, we exploit it with transmission constraints imposed on the transmit power budget and interference to other users. By analyzing the statistics of received SNRs in the first and second hops, we obtain the end-to-end PLR of this scheme in closed form under the considered scenario. Moreover, to compare the proposed scheme with popular relay selection schemes, we also derive the closed-form PLR expressions for partial relay selection (PRS) and opportunistic relay selection (ORS) criteria in the same scenario under study. Illustrative numerical results demonstrate the accuracy of our derivations and substantiate that the proposed relay selection scheme is a promising alternative with respect to the tradeoff between performance and complexity.

  18. A First Look at Modern Enterprise Traffic

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Ruoming; Mark Allman, Mark; Bennett, Mike; Lee, Jason; Paxson, Vern; Tierney, Brian

    2005-06-01

    While wide-area Internet traffic has been heavily studied for many years, the characteristics of traffic inside Internet enterprises remain almost wholly unexplored. Nearly all of the studies of enterprise traffic available in the literature are well over a decade old and focus on individual LANs rather than whole sites. In this paper we present a broad overview of internal enterprise traffic recorded at a medium-sized site. The packet traces span more than 100 hours, over which activity from a total of several thousand internal hosts appears. This wealth of data--which we are publicly releasing in anonymized form--spans a wide range of dimensions. While we cannot form general conclusions using data from a single site, and clearly this sort of data merits additional in-depth study in a number of ways, in this work we endeavor to characterize a number of the most salient aspects of the traffic. Our goal is to provide a first sense of ways in which modern enterprise traffic is similar to wide-area Internet traffic, and ways in which it is quite different.

  19. Traffic breakdown at a signal: classical theory versus the three-phase theory of city traffic

    International Nuclear Information System (INIS)

    Physical reasons for a crucial difference between the results of a three-phase theory developed recently (Kerner 2011 Phys. Rev. E 84 045102(R); 2013 Europhys. Lett. 102 28010; 2014 Physica A 397 76) and the classical theory are explained. Microscopic characteristics of traffic passing a traffic signal during the green signal phase and their dependence on the duration of the green phase have been found. It turns out that a moving synchronized flow pattern (MSP), which occurs in under-saturated traffic at the signal, causes ‘compression’ of traffic flow: the rate of MSP discharge can be considerably larger than the saturation flow rate of the classical traffic theory of city traffic. This leads to a considerably larger rate of traffic passing the signal in comparison with the saturation flow rate. This effect together with traffic behavior at the upstream queue front explains the metastability of under-saturated traffic with respect to a random time-delayed traffic breakdown. (paper)

  20. Traffic breakdown at a signal: classical theory versus the three-phase theory of city traffic

    Science.gov (United States)

    Kerner, Boris S.; Klenov, Sergey L.; Schreckenberg, Michael

    2014-03-01

    Physical reasons for a crucial difference between the results of a three-phase theory developed recently (Kerner 2011 Phys. Rev. E 84 045102(R); 2013 Europhys. Lett. 102 28010; 2014 Physica A 397 76) and the classical theory are explained. Microscopic characteristics of traffic passing a traffic signal during the green signal phase and their dependence on the duration of the green phase have been found. It turns out that a moving synchronized flow pattern (MSP), which occurs in under-saturated traffic at the signal, causes ‘compression’ of traffic flow: the rate of MSP discharge can be considerably larger than the saturation flow rate of the classical traffic theory of city traffic. This leads to a considerably larger rate of traffic passing the signal in comparison with the saturation flow rate. This effect together with traffic behavior at the upstream queue front explains the metastability of under-saturated traffic with respect to a random time-delayed traffic breakdown.