Time travel

Summary

Time travel is the hypothetical activity of traveling into the past or future. Time travel is a widely recognized concept in philosophy and fiction, particularly science fiction. In fiction, time travel is typically achieved through the use of a hypothetical device known as a time machine. The idea of a time machine was popularized by H. G. Wells' 1895 novel The Time Machine. It is uncertain if time travel to the past is physically possible, and such travel, if at all feasible, may give rise to questions of causality. Forward time travel, outside the usual sense of the perception of time, is an extensively observed phenomenon and well-understood within the framework of special relativity and general relativity. However, making one body advance or delay more than a few milliseconds compared to another body is not feasible with current technology. As for backward time travel, it is possible to find solutions in general relativity that allow for it, such as a rotating black hole. Travel

Official source

https://en.wikipedia.org/wiki/Time_travel

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (41)

Related publications

Related people (6)

Related people

Related units (2)

Related units

Related concepts (28)

Related concepts

Related courses (11)

We present the role of particle physics in cosmology and in the description of astrophysical phenomena. We also present the methods and technologies for the observation of cosmic particles.

Bases des références géodésiques, principe de mesure utilisé en localisation par satellites et de l'estimation de la qualité de positions GNSS (Global Navigation Satellites Systems).

Cosmology is the study of the structure and evolution of the universe as a whole. This course describes the principal themes of cosmology, as seen from the point of view of observations.

Related courses

Related lectures (18)

Related lectures

2014

This research deals with self-supplied navigation systems (SNS), a combination of the technology of gathering travel time using floating car data (FCD) and dynamic route guidance (DRG). Using similar on-board equipment, these two systems can easily be combined in the same vehicle. The main goal is to prove the relationship between the percentage of SNS-equipped vehicles and the performance that can be expected from the use of this technology. After the description of the SNS architecture, an evaluation method based on microscopic traffic simulation results is proposed. The different components of a SNS are introduced, particularly the statistics and treatment module, which estimates and predicts travel times from the data transmitted by equipped vehicles. An innovative approach, resulting from the disaggregated observation of these travel times, is proposed in order to improve existing estimation techniques. The description of the parameters influencing this estimation's performance is followed by an analysis of their combined impact. It stresses the necessity of adopting a combination of these parameters, depending on the equipment rate of the vehicles, in order to maximise the estimation's precision. Before the comparison between the performances of equipped and non-equipped vehicles, based on the Lausanne city centre road network, the realism of existing traffic assignment models is analysed. As a consequence, a new alternative for traffic assignment is proposed, consisting of an iterative approach based on the use of historic knowledge of a "typical" day and on a differentiation of three driver categories: standard, expert and tourist. The SNS performance evaluation, mainly in terms of travel time, shows that an equipment rate of only 1 to 2 0/00 is sufficient in order for equipped vehicles to show similar performances to standard drivers, this category representing the majority of drivers. An equipment rate of 5 to 50 0/00 is needed in order to pass above the expert category, which has a perfect knowledge of the road network. For higher equipment rates the benefit compared with the other drivers is less noticeable, but the overall performance of all vehicles is highly improved. Finally, a behaviour study of SNS-equipped vehicles in the case of an incident on the network shows certain limits implied by the fact that the guided vehicles and the ones providing traffic data are the same ones.

EPFL2005

Increasing Traffic Flows with DSRC Technology: Field Trials and Performance Evaluation

Aurélien Pomini

As traffic congestion becomes a huge problem for most developing and developed countries across the world, intelligent transportation systems (ITS) are becoming a hot topic that is attracting attention of researchers and the general public alike. In this paper, we demonstrate a specific implementation of an ITS system whereby traffic lights are actuated by DSRC radios installed in vehicles. More specifically, we report the design of prototype of a DSRC-Actuated Traffic Lights (DSRC-ATL) system. It is shown that this system can reduce the travel time and commute time significantly, especially during rush hours. Furthermore, the results reported in this paper do NOT assume or require all vehicles to be equipped with DSCR radios. Even with low penetration ratios, e.g., when only 20% of all vehicles in a city are equipped with DSRC radios, the overall performance of the designed system is superior to the current traffic control systems.

IEEE2018

EPFL2005