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Three-phase Traffic Theory
Three-phase traffic theory is a theory of traffic flow developed by Boris Kerner between 1996 and 2002. It focuses mainly on the explanation of the physics of traffic breakdown and resulting congested traffic on highways. Kerner describes three phases of traffic, while the classical theories based on the fundamental diagram of traffic flow have two phases: ''free flow'' and ''congested traffic''. Kerner’s theory divides congested traffic into two distinct phases, ''synchronized flow'' and ''wide moving jam'', bringing the total number of phases to three: # Free flow (''F'') # Synchronized flow (''S'') # Wide moving jam (''J'') The word "wide" is used even though it is the length of the traffic jam that is being referred to. A phase is defined as a ''state in space and time.'' Free flow (''F'') In free traffic flow, empirical data show a positive correlation between the flow rate q (in vehicles per unit time) and vehicle density k (in vehicles per unit distance). This rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Theory
A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be scientific, belong to a non-scientific discipline, or no discipline at all. Depending on the context, a theory's assertions might, for example, include generalized explanations of how nature works. The word has its roots in ancient Greek, but in modern use it has taken on several related meanings. In modern science, the term "theory" refers to scientific theories, a well-confirmed type of explanation of nature, made in a way consistent with the scientific method, and fulfilling the criteria required by modern science. Such theories are described in such a way that scientific tests should be able to provide empirical support for it, or empirical contradiction (" falsify") of it. Scientific theories are the most reliable, rigorous, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Autonomous Car
A self-driving car, also known as an autonomous car, driver-less car, or robotic car (robo-car), is a car that is capable of traveling without human input.Xie, S.; Hu, J.; Bhowmick, P.; Ding, Z.; Arvin, F.,Distributed Motion Planning for Safe Autonomous Vehicle Overtaking via Artificial Potential Field IEEE Transactions on Intelligent Transportation Systems, 2022. Self-driving cars use sensors to perceive their surroundings, such as optical and thermographic cameras, radar, lidar, ultrasound/ sonar, GPS, odometry and inertial measurement units. Control systems interpret sensory information to create a three-dimensional model of the surroundings. Based on the model, the car identifies appropriate navigation paths, and strategies for managing traffic controls (stop signs, etc.) and obstacles.Hu, J.; Bhowmick, P.; Jang, I.; Arvin, F.; Lanzon, A.,A Decentralized Cluster Formation Containment Framework for Multirobot Systems IEEE Transactions on Robotics, 2021. Once the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Mathematical Modeling
A mathematical model is a description of a system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used in the natural sciences (such as physics, biology, earth science, chemistry) and engineering disciplines (such as computer science, electrical engineering), as well as in non-physical systems such as the social sciences (such as economics, psychology, sociology, political science). The use of mathematical models to solve problems in business or military operations is a large part of the field of operations research. Mathematical models are also used in music, linguistics, and philosophy (for example, intensively in analytic philosophy). A model may help to explain a system and to study the effects of different components, and to make predictions about behavior. Elements of a mathematical model Mathematical models can take many forms, including dynamical systems, statistica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Kerner’s Breakdown Minimization Principle
Boris S. Kerner (born 1947) is a German physicist and civil engineer who created three phase traffic theory. ttp://www.aps.org/publications/apsnews/200404/upload/apr04.pdf Article by Davis in "APS News" titled "Physicists and traffic flow"/ref> The three phase traffic theory is the framework for the description of empirical vehicular traffic states in three traffic phases: (i) free traffic flow (F), (ii) synchronized traffic flow (S), and (iii) wide moving jam (J). The synchronized traffic flow and wide moving jam phases belong to congested traffic. Biography Kerner is an engineer and physicist. He was born in Moscow, Soviet Union in 1947 and graduated from the Moscow Technical University MIREA in 1972. Boris Kerner was received Ph.D. and Sc.D. (Doctor of Sciences) degrees in the Academy of Sciences of the Soviet Union, respectively, in 1979 and 1986. Between 1972 and 1992, his major interests include the physics of semiconductors, plasma and solid state physics. During thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Nucleation
In thermodynamics, nucleation is the first step in the formation of either a new thermodynamic phase or structure via self-assembly or self-organization within a substance or mixture. Nucleation is typically defined to be the process that determines how long an observer has to wait before the new phase or self-organized structure appears. For example, if a volume of water is cooled (at atmospheric pressure) below 0°C, it will tend to freeze into ice, but volumes of water cooled only a few degrees below 0°C often stay completely free of ice for long periods (supercooling). At these conditions, nucleation of ice is either slow or does not occur at all. However, at lower temperatures nucleation is fast, and ice crystals appear after little or no delay. Nucleation is a common mechanism which generates first-order phase transitions, and it is the start of the process of forming a new thermodynamic phase. In contrast, new phases at continuous phase transitions start to form im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Overtaking
Overtaking or passing is the act of one vehicle going past another slower moving vehicle, travelling in the same direction, on a road. The lane used for overtaking another vehicle is often a passing lane farther from the road shoulder which is to the left in places that drive on the right and to the right in places that drive on the left. Rules of overtaking In English-speaking countries On a single-carriageway/undivided-highway road, the lane used for overtaking is often the same lane that is used by oncoming traffic. An overtaking vehicle must be able to see clearly ahead of them for the entire overtaking manoeuvre plus a margin of error. For example, in New Zealand it's instructed in the Road Code that an overtaking driver must be able to see at least of clear road in front of them as they finish the passing manoeuvre. In the UK, guidance for passing and overtaking is given in rules 162-169 of the Highway Code. In some jurisdictions, the "overtaking zone" is indicate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |