Дисертації з теми "Electronic traffic controls Research"

Networks of maliciously compromised computers, known as botnets, consisting of thousands of hosts have emerged as a serious threat to Internet security in recent years. These compromised systems, under the control of an operator are used to steal data, distribute malware and spam, launch phishing attacks and in Distributed Denial-of-Service (DDoS) attacks. The operators of these botnets use Command and Control (C2) servers to communicate with the members of the botnet and send commands. The communications channels between the C2 nodes and endpoints have employed numerous detection avoidance mechanisms to prevent the shutdown of the C2 servers. Two prevalent detection avoidance techniques used by current botnets are algorithmically generated domain names and DNS Fast-Flux. The use of these mechanisms can however be observed and used to create distinct signatures that in turn can be used to detect DNS domains being used for C2 operation. This report details research conducted into the implementation of three classes of classification techniques that exploit these signatures in order to accurately detect botnet traffic. The techniques described make use of the traffic from DNS query responses created when members of a botnet try to contact the C2 servers. Traffic observation and categorisation is passive from the perspective of the communicating nodes. The first set of classifiers explored employ frequency analysis to detect the algorithmically generated domain names used by botnets. These were found to have a high degree of accuracy with a low false positive rate. The characteristics of Fast-Flux domains are used in the second set of classifiers. It is shown that using these characteristics Fast-Flux domains can be accurately identified and differentiated from legitimate domains (such as Content Distribution Networks exhibit similar behaviour). The final set of classifiers use spatial autocorrelation to detect Fast-Flux domains based on the geographic distribution of the botnet C2 servers to which the detected domains resolve. It is shown that botnet C2 servers can be detected solely based on their geographic location. This technique is shown to clearly distinguish between malicious and legitimate domains. The implemented classifiers are lightweight and use existing network traffic to detect botnets and thus do not require major architectural changes to the network. The performance impact of implementing classification of DNS traffic is examined and it is shown that the performance impact is at an acceptable level.

Thesis (Ph. D.) -- University of Maryland, College Park, 2006.
Thesis research directed by: Applied Mathematics and Scientific Computation Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Thesis (M.S.)--West Virginia University, 2006.
Title from document title page. Document formatted into pages; contains viii, 173 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 75-76).

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.
Includes bibliographical references (leaves 126-129). Also available in electronic version. Access restricted to campus users.

Road safety is an aspect of major concern on road networks, not only on a local scale in South Africa, but also on a global scale. South Africa is experiencing an unacceptably high rate of fatal road traffic crashes and as a result has one of the highest per capita rate of road fatalities in the world. The Global Plan for the Decade of Action for Road Safety 2011 – 2020 was published in 2011 by the World Health Organisation (WHO) to guide and assist countries with the improvement of road safety. The management of vehicle speeds is one of numerous important interventions identified in the Global Plan. The technical and economic feasibility of using a specific Road safety is an aspect of major concern on road networks, not only on a local scale in South Africa, but also on a global scale. South Africa is experiencing an unacceptably high rate of fatal road traffic crashes and as a result has one of the highest per capita rate of road fatalities in the world. The Global Plan for the Decade of Action for Road Safety 2011 – 2020 was published in 2011 by the World Health Organisation (WHO) to guide and assist countries with the improvement of road safety. The management of vehicle speeds is one of numerous important interventions identified in the Global Plan. The technical and economic feasibility of using a specific technology, namely Vehicle Activated Signs (VAS), to contribute to the overall improvement of road safety on a national level in South Africa were investigated, with particular emphasis on the improvement of road safety through the reduction of fatal road traffic crashes. VAS are part of a range of measures that can be used to curb vehicle speeds, similar to conventional measures like speed cameras and traffic calming devices. VAS technology has seen limited use in South extrapolation of results from SCC’s VAS effectiveness study, and the application of these results to the South African road safety and road user statistics for the one year period March 2011 to March 2012. Key factors relating to speed and general driver obedience were also taken into consideration. It was established that the use of VAS would lead to a moderate reduction in the number of fatal road traffic crashes that occur annually, which in turn holds financial and socio-economic benefits for South Africa. A comparison of selected products available from two South African based electronic road sign manufacturing companies with conventional VAS was also carried out, focussing on product function, use and cost. It has been concluded that it would be technically and economically feasible to introduce VAS on the South African road network to improve the prevailing road safety situation.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Hunter, Michael; Committee Member: Meyer, Michael; Committee Member: Rodgers, Michael. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.
Committee Member: Hunter, Michael; Committee Member: Meyer, Michael; Committee Member: Rodgers, Michael. Part of the SMARTech Electronic Thesis and Dissertation Collection.

The objective of this research is to investigate different propagation models to determine if specified models accurately predict received signal levels for short path 900 MHz spread spectrum radio systems. The City of Denton, Texas provided data and physical facilities used in the course of this study. The literature review indicates that propagation models have not been studied specifically for short path spread spectrum radio systems. This work should provide guidelines and be a useful example for planning and implementing such radio systems. The propagation model involves the following considerations: analysis of intervening terrain, path length, and fixed system gains and losses.

Thesis (PhD)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: The debilitating social, economic and environmental ramifications of traffic congestion are experienced in large cities the world over. The optimisation of traffic signal timings at signalised road intersections attempts to mitigate the extent of these adverse effects of traffic congestion by reducing the delay time experienced by vehicles in a transport network. Today, traffic signal control schemes may be classiffied into one of two main classes, namely fixed-time traffic signal control strategies, which are typically cyclic in nature, and vehicle-actuated traffic signal control strategies, which are typically acyclic in nature. Generally, cyclic control strategies tend to lack exibility, and are unable to adapt to short-term uctuations in traffic ow rates, resulting in green times that are either too long or too short. On the other hand, acyclic control strategies tend to lack coordination between intersections, resulting in vehicles being required to stop at the majority of signalised intersections they encounter. Self-organising traffic signal control has been proposed as an attractive alternative form of control which both exhibits exibility and facilitates a global coordination between intersections as a result of localised signal switching policies. Two examples of existing self-organising traffic signal control algorithms from the literature include an algorithm proposed by Lammer and Helbing in 2008 and an algorithm proposed by Gershenson and Rosenblueth in 2012. These algorithms have been shown to outperform both optimised fixed-time traffc signal control techniques as well as state-of-the-art vehicle actuated trffic signal control techniques, in terms of reducing vehicle delay time in a transport network. A draw-back of both of these self-organising approaches, however, is that their effective operation relies on carefully selected parameter values; poorly selected parameter values may render these algorithms very ineffectual. In this dissertation, three novel self-organising traffic signal traffic control algorithms are proposed. These three algorithms assume the use of existing radar detection sensors mounted at the intersection to provide the necessary input data. The radar detection sensors are capable of detecting and tracking individual vehicles approaching an intersection, providing real-time information pertaining to their physical dimensions, velocities, and ranges from the intersection in terms of both time and distance. The three traffic signal control algorithms are free of any user-specialised parameters, and instead rely solely on the data provided by the radar detection sensors to inform their signal switching policies. The first of these traffic signal control algorithms is inspired by inventory control theory, and draws parallels between the monetary costs typically considered in inventory control models and the delay time costs associated with traffic control at signalised intersections, which the algorithm attempts to minimise. The second novel traffic control algorithm is inspired by the chemical process of osmosis in which solvent molecules move unaided from a region where they are highly concentrated, across a semi-permeable membrane, into a region of high solute molecule concentration. The algorithm models vehicles approaching an intersection as solvent molecules and the physical space available for the vehicles to occupy once they have passed through the intersection as solute molecules. Following this analogy, the intersection is considered to be the semi-permeable membrane. The third traffic control algorithm is a hybrid of the inventory and osmosis-inspired algorithms together with an intersection utilisation maximisation technique, which prevents unnecessary or prolonged underutilisation of an intersection. The three novel trafficc control algorithms, together with the algorithms of Lammer and Helbing, and of Gershenson and Rosenblueth, as well as a fixed-time control algorithm, are implemented in a purpose-built microscopic traffic simulation modelling framework. Several measures are employed to evaluate the relative performances of the algorithms. These measures include the usual mean and maximum resulting delay times incurred by vehicles and the saturation level of the roadways in the transport network, as well as three novel performance measure indicators which include the mean number of stops made by vehicles, their mean normalised delay time and the mean normalised number of stops made. The algorithms are compared in the context of a linear corridor road network topology as well as a grid road network topology under various traffic ow conditions. The overall performance of the novel hybrid traffic signal control algorithm is found to be superior for the corridor road network topology, while the performance of the osmosis-inspired algorithm is found to be superior for the grid road network topology.
AFRIKAANSE OPSOMMING:Die negatiewe sosiale, ekonomiese en omgewingsimpak van verkeersopeenhoping word in groot stede regoor die w^ereld ervaar. Die doel met die optimering van verkeersligwerkverrigting by straatkruisings is om die omvang van hierdie negatiewe impak tee te werk deur die vertraging van voertuie in 'n vervoernetwerk te verminder. Hedendaagse verkeersbeheeralgoritmes kom in een van twee hoofklasse voor, naamlik vaste-tyd beheerstrategiee, wat gewoonlik siklies van aard is, en beheerstrategiee gebaseer op voertuigopsporing, wat tipies asiklies van aard is. Oor die algemeen beskik sikliese beheerstrategiee nie oor genoegsame buigsaambeid om aan te pas by kort-termyn fluktuasies in verkeersvloei nie, wat tipies daartoe lei dat hul groentye spesifiseer wat of te lank of te kort is. Aan die ander kant is asikliese beheerstrategiee nie daartoe in staat om koordinasie tussen naasliggende straatkruisings te bewerkstellig nie, wat weer daartoe lei dat voertuie genoodsaak word om by die oorgrote meerderheid straatkruisings op hul pad te stop. Die self-organiserende beheer van verkeersligte is as 'n aantrektlike, buigsame alternatief voorgestel wat in staat is om globale koordinasie tussen naasliggende straatkruisings as gevolg van gelokaliseerde seinstrategiee te bewerkstellig. Twee voorbeelde van bestaande self-organiserende verkeersbeheeralgoritmes in die literatuur is die algoritmes wat in 2008 deur Lammer and Helbing en in 2012 deur Gershenson en Rosenblueth voorgestel is. Daar is aangetoon dat hierdie algoritmes daartoe in staat is om ge-optimeerde vaste-tyd beheerstrategiee sowel as gevorderde strategiee gebaseer op voertuigopsporing uit te stof in terme van 'n vermindering van die vertraging van voertuie in 'n vervoernetwerk. 'n Nadeel van beide hierdie self-organiserende benaderings is egter dat hul doeltreffende werkverrigting berus op versigtig-gekose parameterwaardes; willekeurige parameterwaardes mag lei na hoogs ondoeltreffende werkverrigitng van die algoritmes. Drie nuwe self-organiserende verkeersbeheeralgoritmes word in hierdie proefskrif voorgestel. Hierdie drie algoritmes maak vir hul toevoerdata staat op die beskikbaarhed van bestaande radar opsporingsensors wat by straatkruisings geinstalleer is. Die sensors is daartoe in staat om individuele voertuie wat 'n straatkruising nader, op te spoor, te volg en intydse data oor hul fisiese dimensies, snelhede, en afstande na die kruising (in terme van beide tyd en afstand) te lewer. Die drie algoritmes bevat geen gebruikers-gespesifiseerde parameters nie, en maak in plaas daarvan slegs gebruik van die sensortoevoerdata om hul beheerstrategiee te bepaal. Die eerste van hierdie verkeersbeheeralgoritmes is deur die teorie van voorraadbeheer geinspireer en maak gebruik van parallelle tussen die monet^ere kostes wat tipies in voorraadbeheermodelle voorkom en die kostes in terme van vertragingstyd wat met verkeersbeheer by straatkruisings aangegaan word, en wat deur die algoritme geminimeer word. Die tweede verkeersbeheeralgoritme is deur die chemiese proses van osmose geinspireer, waar molekules van 'n oplossingsmiddel sonder eksterne hulp vanaf 'n gebied waar hul in hoe konsentrasie voorkom, deur 'n gedeeltelik-deurlaatbare membraan beweeg na 'n gebied waarin hul ook in hoe konsentrasie, maar in opgeloste vorm voorkom. Die algoritme modelleer voertuie wat 'n straatkruising nader as die molekules van die oplossingsmiddel en die fisiese ruimte wat aan die ander kant van die kruising beskikbaar is om deur voertuie beset te word, as molekules in opgeloste vorm. In hierdie analogie word die kruising self as die gedeeltelik-deurlaatbare membraan beskou. Die derde algoritme is 'n hibriede strategie waarin elemente van die eerste twee algoritmes in samewerking met 'n tegniek vir die maksimering van straatkruisingsbenutting gekombineer word, en wat wat ten doel het om onnodige of verlengte onderbenutting van die kruising te vermy. Hierdie drie nuwe verkeersbeheeralgoritmes word, tesame met die bestaande algoritmes van Lammer en Helbing, en van Gershenson en Rosenblueth, asook 'n vaste-tyd beheeralgoritme, in 'n mikroskopiese verkeersimulasiemodelleringsraamwerk wat spesifiek vir die doel ontwerp is, geimplementeer. Verskeie maatstawwe word ingespan om die relatiewe werkverrigting van die algoritmes te evalueer. Hierdie maatstawwe sluit in die gebruiklike gemiddelde en maksimum vertragingstye van voertuie en die versadigingsvlak van strate in die vervoernetwerk, sowel as drie nuwe maatstawwe, naamlik die gemiddelde aantal stoppe deur voertuie, hul genormaliseerde vertragingstye en die gemiddelde, genormaliseerde aantal stoppe. Die algoritmes word in die kontekste van 'n line^ere topologie van opeenvolgende straatkruisings en 'n netwerktopologie van reghoekige straatblokke onder verskeie verkeersdigthede met mekaar vergelyk. Daar word bevind dat die nuwe hibriede algoritme die beste vaar in die line^ere topologie, terwyl die osmose-ge inspireerde algoritme die ander algoritmes uitstof in die straatblok-netwerktopologie.

This report represents a concentrated effort that determines the feasibility of audible pedestrian signals. These signals are devices which give auditory cues to help the visually impaired cross safely at difficult intersections. Surveys were sent out to over 100 organizations, audible signal manufacturers, and cities who have knowledge of the devices, and responses were analyzed. The devices were found to be feasible but only at certain complex and confusing intersections. Twelve criteria for the installation of the devices were developed as were twelve criteria for the operation of the devices. Buzzers, constant tones, bird calls, and voice signals were examined by obtaining information from traffic engineers who had experience with each sound. It was determined that intermittent tones were the most effective for human localization. For the most widely used devices, cost data were developed for the products, installation, and maintenance. A partial listing of the U.S. and foreign cities which have the devices was compiled along with a partial listing of audible signal manufacturers. The problems the visually impaired face as well as their suggested solutions are listed. Topics for further study include the use of hand-held devices which activate sound signals at intersections and the development of tone schemes for 4-leg and multi-leg intersections which are not north south and east-west. An additional topic for future study is the development of tone schemes for traffic circles.
Master of Science

Thesis (MScEng)--Stellenbosch University, 2001.
ENGLISH ABSTRACT: With the increased focus on the use of innovative and state-of-the-art technology in Intelligent Transport Systems (ITS), the need for more accurate and more detailed road traffic flow data has become apparent. Data obtained from vehicle detector loops, which merely act as vehicle presence sensors, is neither reliable nor accurate enough anymore. This type of sensor poses the problem that it has to be inserted into the road surface; temporarily obstructing traffic flows, and has to be replaced after pavement reconstruction. One of the solutions to this problem is to develop a traffic surveillance system that uses video image processing. In cities where Intelligent Transport Systems are used extensively, roadways are monitored through Closed Circuit Television Cameras (CCTV) that are closely watched by traffic control centre personnel. These cameras are mounted on posts on the roadside. These cameras can serve a dual purpose, being used for both human monitoring and as inputs to Video Image Processing Systems. In this study some of the digital image processing techniques that could be used in a traffic surveillance system were investigated. This report leads the reader through the various steps in the processing of a scene by a traffic surveillance system based on feature tracking, and discusses the pitfalls and problems that are experienced. The tracker was tested using three image sequences and the results are presented in the final chapter of this report.
AFRIKAANSE OPSOMMING: Met die toenemende fokus op die gebruik van innoverende oplossings en gevorderde tegnologie in Intelligente Vervoerstelsels, het die noodsaaklikheid van akkurater en meer gedetailleerde padverkeer vloeidata duidelik geword. Data wat verkry word d.m.v. voertuig deteksie lusse, wat alleenlik voertuig teenwoordigheid/afwesigheid meet, is nie meer akkuraat of betroubaar genoeg nie. Hierdie tipe sensors het egter die nadeel dat dit in die plaveisel ingesny moet word, dus vloei tydelik kan belemmer, en moet vervang word elke keer as plaveisel rekonstruksie gedoen word. Een van die oplossings vir hierdie probleem is om 'n verkeers waarnemingstelsel te ontwikkel wat van videobeeldverwerking gebruik maak. In stede waar van uitgebreide intelligente verkeerstelsels gebruik gemaak word, word paaie gemonitor d.m.v. geslote baan televisiekameras wat op pale langs die paaie aangebring is. Personeellede van die verkeers beheer sentrum hou dan die inkomende televisiebeelde dop. Hierdie kameras kan 'n dubelle rol vervul deurdat dit vir beide menslike waarneming en as invoer in 'n video-beeldverwerking stelsel gebruik kan word. In hierdie studie was verskeie digitale beeldverwerking tegnieke wat gebruik kan word in 'n verkeers waarnemingstelsel ondersoek. Hierdie verslag lei die leser deur die verskeie stappe in die verwerking van 'n toneel deur 'n verkeers waarneming stelsel wat gebaseer is op die volg van kenmerke. Die verslag beskryf ook die slaggate en probleme wat ondervind word. Die voertuig volger was getoets deur van drie reekse beelde gebruik te maak en die resultate word weergegee in die finale hoodfstuk van hierdie verslag.

This study aims at calculating the traffic signal timing that suits traffic intensity at intersections studied in the inner city of Ubon Rachathani Provice, Thailand. The mixed models between maximum likelihood estimation and Bayesian inference are presented to estimate traffic intensity. A queuing system is used to generate the performance of traffic flow. A fuzzy logic system is applied to calculate the optimal length of each phase of the cycle. The fortran language is used to produce the computer program for computation. The algorithm of the computer programming is based on EM algorithm, Markov Chain Monte Carlo algorithm, queuing generation and fuzzy logic. The output of traffic signal timing from the fuzzy controller are longer than the traffic signal timing from the conventional controller. Cost function is used to evaluate the efficiency of the traffic controller. The result of the evaluation shows that fuzzy controller is more efficient than a conventional controller.

One of the most effective measures of congestion control on freeways has been ramp metering, where vehicle entry to the freeway is regulated by traffic signals (meters). Meters are run with calibrated influx rates to prevent highway saturation. However, recent observations of some metering sites in San Diego, CA indicate that metering, during peak hour demand, is helping freeway flow while sometimes creating considerable traffic back-ups on local streets, transferring congestion problems from the freeway to intersections. Metering problems stem largely from the difficulty of designing an integrated, dynamic metering scheme that responds not only to changing freeway conditions but also to fluctuating demand throughout the ramp network; a scheme whose objective is to maintain adequate freeway throughput as well as minimize disproportionate ramp delays and queue overspills onto surface streets. Simulation modeling is a versatile, convenient, relatively inexpensive and safe systems analysis tool for evaluating alternative strategies to achieve the above objective. The objective of this research was to establish a basic building block for a discrete system simulation model, ONRAMP, based on a stochastic, mesoscopic, queueing approach. ONRAMP is for modeling entrance ramp geometry, vehicular generation, platooning and arrivals, queueing activities, meters and metering rates. The architecture of ONRAMP's molecular unit is designed in a fashion so that it can be, with some model calibration, duplicated for a number of ramps and, if necessary, integrated into some other larger freeway network models. SLAM.II simulation language is used for computer implementation. ONRAMP has been developed and partly validated using data from eight ramps at Interstate-B in San Diego. From a systems perspective, simulation will be short-sided and problem analysis is incomplete unless the other non-technical metering problems are explored and considered. These problems include the impacts of signalizing entrance ramps on the vitality of adjacent intersections, land use and development, "fair" geographic distribution of meters and metering rates throughout the freeway corridor, public acceptance and enforcement, and the role and influence of organizations in charge of decision making in this regard. Therefore, an outline of a contextual systems approach for problem analysis is suggested. Benefits and problems of freeway control via ramp metering, both operational short-term and strategic long-term, are discussed in two dimensions: global (freeway) and local (intersection). The results of a pilot study which includes interviews with field experts and law enforcement officials and a small motorist survey are presented.

The deployment of third generation (3G) cellular systems is resulting in a transition from cellular systems that predominantly carry constant-bit-rate (CBR) voice traffic to multi-service packet based systems that predominantly carry variable-bit-rate (VBR) traffic. With 3G DS-CDMA cellular systems there is a direct relationship between user traffic and propagation dependent performance as additional traffic causes increased system interference. This thesis investigates the impact of VBR traffic on the propagation dependent performance of DS-CDMA cellular systems that utilise frame-by-frame dynamic resource allocation on the radio channel. A DS-CDMA cellular system model is developed and the downlink performance of both outdoor macro-cellular and indoor pico-cellular systems is evaluated with a variety of traffic types. Both traffic scheduling performance and propagation dependent performance are evaluated as the two are inter-linked. Scenarios are identified where propagation dependent performance is sensitive to the statistical properties of the user traffic streams and it is shown that a significant performance difference potentially exists between different traffic types when the number of users per cell is low. When a significant performance difference does exist, burstier more variable traffic generally results in superior propagation dependent performance. The base transceiver station (BTS) transmitter power mean and variance provides a good indication of the level of propagation dependent performance regardless of the specific traffic type. Traffic scheduling policies that deliberately reduce the variability of user traffic streams are considered and in terms of propagation dependent performance these are shown to have a minimal impact on the performance difference between different traffic types. The implications of VBR traffic on DS-CDMA cellular system design are outlined and it is shown that VBR traffic can be approximated as CBR traffic in many scenarios and this is a convenient approximation as it simplifies system design and detailed traffic models do not need to be developed.

Rising from the “excess demand” modern societies and economies place on limited road resources, congestion causes increased vehicle emissions, decreases national efficiency, and wastes time (Downs, 2004). In order to minimise congestion’s impacts, traffic management systems gather traffic data and use it to implement efficient management algorithms (Downs, 2004). This dissertation’s purpose has been the development of a distributable vehicle presence detection sensor, which will wirelessly provide vehicle presence information in real time. To address the sensor’s wireless power requirements, the feasibility of self-powering the device via harvested energy has been investigated. Piezoelectric, electrostatic, and electromagnetic energy harvesting devices’ principles of operation and underlying theory has been investigated in detail and an overview presented alongside a literature review of previous vibration energy harvesting research. An electromagnetic energy harvesting device was designed, which consists of: a nylon reinforced rubber bladder, hydraulic piston, neodymium magnets, and wire-wound coil housing. Preliminary testing demonstrated a harvested energy between 100mJ and 205mJ per axle. This amount is able to be transferred to a 100O load when driven over at speeds between 10km/h and 50km/h. Combined with an embedded circuit, the energy harvester facilitated the development of a passive sensor, which is able to wirelessly transmit a vehicle’s presence signal to a host computer. The vehicle detected event is displayed via a graphical user interface. Energy harvesting’s ability to power the embedded circuit’s wireless transmission, demonstrated the feasibility of developing systems capable of harvesting energy from their environment and using it to power discrete electronic components. The ability to wirelessly transmit a vehicle’s presence facilitates the development of distributable traffic monitoring systems, allowing for remote traffic monitoring and management.

Safety and congestion are ever present and increasingly severe transportation problems in urban areas throughout the nation and world. These phenomena can have wide-ranging consequences relating to safety, the economy, and the environment. Adverse weather conditions represent another significant challenge to safety and mobility on highways. Oregon is not immune from either of these global issues. Oregon Route (OR) 217, to the southwest of the downtown Portland, is one of the worst freeways for congestion in the state and is also subject to the Pacific Northwest's frequently inclement and unpredictable climate. High crash rates, severe recurrent bottlenecks and highly unreliable travel times continuously plague the corridor, making it a major headache for the thousands of commuters using it every day. In an effort to more effectively combat both congestion and adverse weather, transportation officials all over the world have been turning to increasingly technological strategies like Active Traffic Management (ATM). This can come in many forms, but among the most common are variable speed limit (VSL) systems which use real-time data to compute and display appropriate reduced speeds during congestion and/or adverse weather. After numerous studies and deliberations, Oregon Department of Transportation (ODOT) selected Oregon Route (OR) 217 as one of the first locations in the state to be implemented with an advisory VSL system, and that system began operation in the summer of 2014. This thesis seeks to evaluate the effectiveness of this VSL system through the first eight months of its operation through an in-depth and wide-ranging "before and after" analysis. Analysis of traffic flow and safety data for OR 217 from before the VSL system was implemented made clear some of the most prevalent issues which convinced ODOT to pursue VSL. Using those issues as a basis, a framework of seven specific evaluation questions relating to both performance and safety, as well as both congestion and adverse weather, was established to guide the "before and after" comparisons. Hypotheses, and measures of effectiveness for each question were developed, and data were obtained from a diverse array of sources including freeway detectors, ODOT's incident database, and the National Oceanic and Atmospheric Administration (NOAA). The results of the various "before and after" comparisons performed as a part of this thesis indicate that conditions have changed on OR 217 in a number of ways since the VSL system was activated. Many, but not all, of the findings were consistent with the initial hypotheses and with the findings from other VSL studies in the literature. Certain locations along the corridor have seen significant declines in speed variability, supporting the common notion that VSL systems have a harmonizing effect on traffic flow. Crash rates have not decreased, but crashes have become less frequent in the immediate vicinity of VSL signs. Flow distribution between adjacent lanes has been more even since VSL implementation during midday hours and the evening peak, and travel time reliability has seen widespread improvement in three of the corridor's four primary travel lanes during those same times. The drops in flow that generally occur upstream of bottlenecks once they form have had diminished magnitudes, while the drops in flow downstream of the same bottlenecks have grown. Finally, the increase in travel times that is usually brought about by adverse weather has been smaller since VSL implementation, while the decline in travel time reliability has largely disappeared.

Bus priority treatments such as busways, bus lanes and bus priority at traffic signals are all utilised in Australian metropolitan areas. These treatments are designed to reduce the travel time for buses and make this transportation mode more efficient and attractive. The common applications of such treatments for Australian conditions are assessed in this research to identify the travel time impacts of introducing bus priority. This will assist in the selection of bus priority measures on arterial roads for Australian conditions. The methodology applied here entails the identification of optimum conditions for using typical bus priority treatments. This research identifies the number of bus passengers necessary to justify various forms of bus priority treatments with varying traffic conditions. The traffic conditions modelled varied from low through to high degree of saturation for general purpose traffic on the road network. The resultant analyses demonstrated that as the degree of saturation increases, higher numbers of bus passengers are necessary to justify reducing the capacity by introducing bus priority. It is concluded however that an economic analysis using travel time costs should not be the only criteria used to identify the appropriate bus priority treatment. It is suggested that bus priority should be part of an overall traffic management approach in conjunction with cost disincentives to cars and appropriate marketing for public transport. The current trends in bus priority treatments are addressed by considering a case study for the Gold Coast Highway located on Queensland's Gold Coast. This work provides an evaluation of bus priority treatments and conditions for justification for such measures. The research summarises the impact of introducing bus lanes, transit lanes, bus priority at traffic signals and improved passenger information and ticketing systems for the Gold Coast Highway. The analysis indicates that journey time saving for buses of up to 20 percent may be achieved with these bus priority treatments.

Indiana University-Purdue University Indianapolis (IUPUI)
Yan, Jiaxiang. M.S.E.C.E., Purdue University, May 2013. Modeling, Monitoring and Optimization of Discrete Event Systems Using Petri Nets. Major Professor: Lingxi Li. In last decades, the research of discrete event systems (DESs) has attracts more and more attention because of the fast development of intelligent control strategies. Such control measures combine the conventional control strategies with discrete decision-making processes which simulate human decision-making processes. Due to the scale and complexity of common DESs, the dedicated models, monitoring methods and optimal control strategies for them are necessary. Among various DES models, Petri nets are famous for the advantage in dealing with asynchronous processes. They have been widely applied in intelligent transportation systems (ITS) and communication technology in recent years. With encoding of the Petri net state, we can also enable fault detection and identification capability in DESs and mitigate potential human errors. This thesis studies various problems in the context of DESs that can be modeled by Petri nets. In particular, we focus on systematic modeling, asynchronous monitoring and optimal control strategies design of Petri nets. This thesis starts by looking at the systematic modeling of ITS. A microscopic model of signalized intersection and its two-layer timed Petri net representation is proposed in this thesis, where the first layer is the representation of the intersection and the second layer is the representation of the traffic light system. Deterministic and stochastic transitions are both involved in such Petri net representation. The detailed operation process of such Petri net representation is stated. The improvement of such Petri net representation is also provided with comparison to previous models. Then we study the asynchronous monitoring of sensor networks. An event sequence reconstruction algorithm for a given sensor network based on asynchronous observations of its state changes is proposed in this thesis. We assume that the sensor network is modeled as a Petri net and the asynchronous observations are in the form of state (token) changes at different places in the Petri net. More specifically, the observed sequences of state changes are provided by local sensors and are asynchronous, i.e., they only contain partial information about the ordering of the state changes that occur. We propose an approach that is able to partition the given net into several subnets and reconstruct the event sequence for each subnet. Then we develop an algorithm that is able to reconstruct the event sequences for the entire net that are consistent with: 1) the asynchronous observations of state changes; 2) the event sequences of each subnet; and 3) the structure of the given Petri net. We discuss the algorithmic complexity. The final problem studied in this thesis is the optimal design method of Petri net controllers with fault-tolerant ability. In particular, we consider multiple faults detection and identification in Petri nets that have state machine structures (i.e., every transition in the net has only one input place and one output place). We develop the approximation algorithms to design the fault-tolerant Petri net controller which achieves the minimal number of connections with the original controller. A design example for an automated guided vehicle (AGV) system is also provided to illustrate our approaches.

Indiana University-Purdue University Indianapolis (IUPUI)
In recent decades, Petri nets (PNs) have been used to model traffic networks for different purposes, such as signal phase control, routing, and traffic flow estimation, etc. Because of the complex nature of traffic networks where both discrete and continuous dynamics come into play, the Hybrid Petri net (HPN) model becomes an important tool for the modeling and analysis of traffic networks. In Chapter 1 a brief historical summery about traffic systems control and then related work is mentioned followed by the major contributions in this research. Chapter 2 provides a theoretical background on Petri nets. In Chapter 3, we develop a HPN model for a single signalized intersection first, then we extend this model to study a simple traffic network that consists of two successive intersections. Time delays between different points of network are also considered in order to make the model suitable for analysis and simulation. In addition to HPN models, we also consider discrete Petri nets where their modeling simplicity enables the characterization of the occurrences of all events in the system. This discrete PN is particularly useful to give a higher-level representation of the traffic network and study its event occurrences and correlations. In Chapter 4, we build a discrete PN model to represent a traffic network with two successive intersections. However, we find that the model leads to unbounded places which cannot accurately reflect the dynamics of the traffic in terms of event occurrences. Hence, we introduce the Modified Binary Petri nets (MBPN) to overcome the limitation and resolve the confliction problem when we design our controllers. This MBPN model is a powerful tool and can be useful for the modeling and analysis of many other applications in traffic networks. Chapter 5 gives a summary for each chapter, provides conclusion and discusses future work for both discrete and hybrid Petri nets.

M.Ing. (Transportation)
Consecutive green phases at signalized intersections are separated by an amber and sometimes all-red period to allow a safe changeover from flow in one direction to another. Al though this signal change interval consists of only a few seconds, existing practice in setting this signal change interval varies considerably. Research on this subj ect has focused on understanding how individual drivers react when they are confronted by a change signal. Identifying the factors that describe the need for different change intervals can most easily be determined by measuring the aggregated behaviour of motorists under conditions where these factors vary. Evidence suggests that the South African driver overseas counterpart regarding his attitude towards interval differs from his the signal change Field observations of drivers' aggregated behaviour when confronted by a change interval were made at 17 approaches to 9 different intersections. The linear relationship between the signal change interval and various factors which apparently have an influence on the need for such a period were determined. The regression models were also structured to allow evaluation of existing models such as the well-known ITE-formula. The results were evaluated statistically. It was not possible to calibrate the ITE-formula for South African conditions. The approach adopted here conforms to tiling designs that use a constant (for a specific approach) amber interval. This constant is probably a summation of the influence of all the factors which influence the need for a signal change interval. The use of the clearance time for a crossing, as the all-red period, is also ascertained.

Thesis (Ph. D.)--Florida International University, 2006.
Includes bibliographical references (p. 146-152). Also available online via the Florida International University Digital Commons website (http://digitalcommons.fiu.edu/).

近年來，在公開的大規模人工標注數據集上訓練通用行人檢測器的方法有了顯著的進步。然而，當通用行人檢測器被應用到一個特定的，未公開過的場景中時，它的性能會不如預期。這是由待檢測的數據（源樣本）與訓練數據（目標樣本）的不匹配，以及新場景中視角、光照、分辨率和背景噪音的變化擾動造成的。
在本論文中，我們提出一個新的自動將通用行人檢測器適應到特定場景中的框架。這個框架分為兩個階段。在第一階段，我們探索監控錄像場景中提供的特定表征。利用這些表征，從目標場景中選擇正負樣本並重新訓練行人檢測器，該過程不斷迭代直至收斂。在第二階段，我們提出一個新的機器學習框架，該框架綜合每個樣本的標簽和比重。根據這些比重，源樣本和目標樣本被重新權重，以優化最終的分類器。這兩種方法都屬於半監督學習，僅僅需要非常少的人工干預。
使用提出的方法可以顯著提高通用行人檢測器的准確性。實驗顯示，由方法訓練出來的檢測器可以和使用大量手工標注的目標場景數據訓練出來的媲美。與其它解決類似問題的方法比較，該方法同樣好於許多已有方法。
本論文的工作已經分別於朲朱朱年和朲朱朲年在杉杅杅杅計算機視覺和模式識別會議（权杖材杒）中發表。
In recent years, significant progress has been made in learning generic pedestrian detectors from publicly available manually labeled large scale training datasets. However, when a generic pedestrian detector is applied to a specific, previously undisclosed scene where the testing data (target examples) does not match with the training data (source examples) because of variations of viewpoints, resolutions, illuminations and backgrounds, its accuracy may decrease greatly.
In this thesis, a new framework is proposed automatically adapting a pre-trained generic pedestrian detector to a specific traffic scene. The framework is two-phased. In the first phase, scene-specific cues in the video surveillance sequence are explored. Utilizing the multi-cue information, both condent positive and negative examples from the target scene are selected to re-train the detector iteratively. In the second phase, a new machine learning framework is proposed, incorporating not only example labels but also example confidences. Source and target examples are re-weighted according to their confidence, optimizing the performance of the final classifier. Both methods belong to semi-supervised learning and require very little human intervention.
The proposed approaches significantly improve the accuracy of the generic pedestrian detector. Their results are comparable with the detector trained using a large number of manually labeled frames from the target scene. Comparison with other existing approaches tackling similar problems shows that the proposed approaches outperform many contemporary methods.
The works have been published on the IEEE Conference on Computer Vision and Pattern Recognition in 2011 and 2012, respectively.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Wang, Meng.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 42-45).
Abstracts also in Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- PedestrianDetection --- p.1
Chapter 1.1.1 --- Overview --- p.1
Chapter 1.1.2 --- StatisticalLearning --- p.1
Chapter 1.1.3 --- ObjectRepresentation --- p.2
Chapter 1.1.4 --- SupervisedStatisticalLearninginObjectDetection --- p.3
Chapter 1.2 --- PedestrianDetectioninVideoSurveillance --- p.4
Chapter 1.2.1 --- ProblemSetting --- p.4
Chapter 1.2.2 --- Challenges --- p.4
Chapter 1.2.3 --- MotivationsandContributions --- p.5
Chapter 1.3 --- RelatedWork --- p.6
Chapter 1.4 --- OrganizationsofChapters --- p.9
Chapter 2 --- Label Inferring by Multi-Cues --- p.10
Chapter 2.1 --- DataSet --- p.10
Chapter 2.2 --- Method --- p.12
Chapter 2.2.1 --- CondentPositiveExamplesofPedestrians --- p.13
Chapter 2.2.2 --- CondentNegativeExamplesfromtheBackground --- p.17
Chapter 2.2.3 --- CondentNegativeExamplesfromVehicles --- p.17
Chapter 2.2.4 --- FinalSceneSpecicPedestrianDetector --- p.19
Chapter 2.3 --- ExperimentResults --- p.20
Chapter 3 --- Transferring a Detector by Condence Propagation --- p.24
Chapter 3.1 --- Method --- p.25
Chapter 3.1.1 --- Overview --- p.25
Chapter 3.1.2 --- InitialEstimationofCondenceScores --- p.27
Chapter 3.1.3 --- Re-weightingSourceSamples --- p.27
Chapter 3.1.4 --- Condence-EncodedSVM --- p.30
Chapter 3.2 --- Experiments --- p.33
Chapter 3.2.1 --- Datasets --- p.33
Chapter 3.2.2 --- ParameterSetting --- p.35
Chapter 3.2.3 --- Results --- p.36
Chapter 4 --- Conclusions and Future Work --- p.40

M.Ing. (Mechanical Engineering)
The purpose of this study was to investigate the accuracy of SOAP84-simulations of delay and percentage stops at isolated signalized intersections. In the application, capacity was distinguished in terms of lane configuration only. Results at the intersections showed SOAP overestimating both delay and percentage stops by as much as 100%. It is recommended that the same investigations be repeated with more accurate information on the capacity of the intersections.

Thesis (M.S.)--Florida State University, 2006.
Advisor: James R. Simpson, Florida State University, College of Engineering, Dept. of Industrial Engineering. Title and description from dissertation home page (viewed Sept. 22, 2006). Document formatted into pages; contains ix, 95 pages. Includes bibliographical references.