555 research outputs found
Bicycle traffic and its interaction with motorized traffic in an agent-based transport simulation framework
Cycling as an inexpensive, healthy, and efficient mode of transport for everyday traveling is becoming increasingly popular. While many cities are promoting cycling, it is rarely included in transport models and systematic policy evaluation procedures. The purpose of this study is to extend the agent-based transport simulation framework MATSim to be able to model bicycle traffic more realistically. The network generation procedure is enriched to include attributes that are relevant for cyclists (e.g. road surfaces, slopes). Travel speed computations, plan scoring, and routing are enhanced to take into account these infrastructure attributes. The scoring, i.e. the evaluation of simulated daily travel plans, is furthermore enhanced to account for traffic events that emerge in the simulation (e.g. passings by cars), which have an additional impact on cyclists’ decisions. Inspired by an evolutionary computing perspective, a randomizing router was implemented to enable cyclists to find realistic routes. It is discussed in detail why this approach is both feasible in practical terms and also conceptually consistent with MATSim’s co-evolutionary simulation approach. It is shown that meaningful simulation results are obtained for an illustrative scenario, which indicates that the developed methods will make real-world scenarios more realistic in terms of the representation of bicycle traffic. Based on the exclusive reliance on open data, the approach is spatially transferable
Too close? lnvestigating the distance between cars and bikes when overtaking with regards to the infrastructure using the OpenBikeSensor and information from OpenStreetMap
Cycling in Germany- and also in many countries in Europe and all over the world-has become more relevant in recent years especially due to the corona pandemic. People have been afraid using public transport and tend to use individual means of transport more intensive. Many cities across Europe supported cycling and pop-up cycle lanes were marked on streets with yellow lines in order to give cyclists more space for safe and comfortable riding. Cities like Brussels, Vienna or Berlin implemented these kinds of ''unconventional' infrastructure in 2020 during tbe first Corona lockdowns. Though, evaluations have shown that the use of these pop-up lanes led to increasing numbers of users on these tracks, these tracks were marked only on a marginal share of the streets in contrast to the whole cycling network of a city. Other indicators depicting that cycling is advancing are the numbers of sales and the increased willingness to pay for a new bicycle. In Germany, the average price over all sold bicycles in 2021 was about €1,400 EUR. Compared to 2019 (€929 per bike) this is an increase ofabout 50%. This increase of sales numbers of e-bikes explains this increase. In 2021 about two million e-bikes were sold in Germany in contrast to 2. 7 million conventional bikes. The overall market value of sold bicycles in Germany was 6.56 billion euros which is an increase by 60% in comparison to 2011. Nevertheless, a recent Germany-wide survey with over 11,000 participants shows that 91 % of tbe cyclists feel unsafe in Gennan traffic. 69% state that the keeping too little distance between other traffic participants is one of the reasons that people feel unsafe in traffic. The survey also reveals that the feeling of safety would increase by building more bicycle infrastructure (81%) and a clear separation between motorized and nonmotorized
traffic (62%). [from Introduction
Global Optimization of Minority Game by Smart Agents
We propose a new model of minority game with so-called smart agents such that
the standard deviation and the total loss in this model reach the theoretical
minimum values in the limit of long time. The smart agents use trail and error
method to make a choice but bring global optimization to the system, which
suggests that the economic systems may have the ability to self-organize into a
highly optimized state by agents who are forced to make decisions based on
inductive thinking for their limited knowledge and capabilities. When other
kinds of agents are also present, the experimental results and analyses show
that the smart agent can gain profits from producers and are much more
competent than the noise traders and conventional agents in original minority
game.Comment: 5 pages, 5 figure
Directed motion emerging from two coupled random processes: Translocation of a chain through a membrane nanopore driven by binding proteins
We investigate the translocation of a stiff polymer consisting of M monomers
through a nanopore in a membrane, in the presence of binding particles
(chaperones) that bind onto the polymer, and partially prevent backsliding of
the polymer through the pore. The process is characterized by the rates: k for
the polymer to make a diffusive jump through the pore, q for unbinding of a
chaperone, and the rate q kappa for binding (with a binding strength kappa);
except for the case of no binding kappa=0 the presence of the chaperones give
rise to an effective force that drives the translocation process. Based on a
(2+1) variate master equation, we study in detail the coupled dynamics of
diffusive translocation and (partial) rectification by the binding proteins. In
particular, we calculate the mean translocation time as a function of the
various physical parameters.Comment: 22 pages, 5 figures, IOP styl
Modeling bicycle traffic in an agent-based transport simulation
Cycling as an inexpensive, healthy, and efficient mode of transport for everyday traveling is becoming increasingly popular. While many cities are promoting cycling, it is rarely included in transport models and systematic policy evaluation procedures. The purpose of this study is to extend the agent-based transport simulation framework MATSim to take into account attributes of the infrastructure that are relevant for cycling and the decisions that cyclists take. It is shown that meaningful simulation results are obtained for both an illustrative test scenario and a Berlin scenario. Further attributes (e.g. personal or bicycle-related attributes) that have an effect on the behavior of cyclists can be included into the simulation and, by this, into policy evaluation. Based on the exclusive reliance on open data, the approach is transferable to other spatial contexts
Subdiffusive transport in intergranular lanes on the Sun. The Leighton model revisited
In this paper we consider a random motion of magnetic bright points (MBP)
associated with magnetic fields at the solar photosphere. The MBP transport in
the short time range [0-20 minutes] has a subdiffusive character as the
magnetic flux tends to accumulate at sinks of the flow field. Such a behavior
can be rigorously described in the framework of a continuous time random walk
leading to the fractional Fokker-Planck dynamics. This formalism, applied for
the analysis of the solar subdiffusion of magnetic fields, generalizes the
Leighton's model.Comment: 7 page
Dynamics of DNA Ejection From Bacteriophage
The ejection of DNA from a bacterial virus (``phage'') into its host cell is
a biologically important example of the translocation of a macromolecular chain
along its length through a membrane. The simplest mechanism for this motion is
diffusion, but in the case of phage ejection a significant driving force
derives from the high degree of stress to which the DNA is subjected in the
viral capsid. The translocation is further sped up by the ratcheting and
entropic forces associated with proteins that bind to the viral DNA in the host
cell cytoplasm. We formulate a generalized diffusion equation that includes
these various pushing and pulling effects and make estimates of the
corresponding speed-ups in the overall translocation process. Stress in the
capsid is the dominant factor throughout early ejection, with the pull due to
binding particles taking over at later stages. Confinement effects are also
investigated, in the case where the phage injects its DNA into a volume
comparable to the capsid size. Our results suggest a series of in vitro
experiments involving the ejection of DNA into vesicles filled with varying
amounts of binding proteins from phage whose state of stress is controlled by
ambient salt conditions or by tuning genome length.Comment: 17 pages, 5 figure
Chaperone-assisted translocation of a polymer through a nanopore
Using Langevin dynamics simulations, we investigate the dynamics of
chaperone-assisted translocation of a flexible polymer through a nanopore. We
find that increasing the binding energy between the chaperone and
the chain and the chaperone concentration can greatly improve the
translocation probability. Particularly, with increasing the chaperone
concentration a maximum translocation probability is observed for weak binding.
For a fixed chaperone concentration, the histogram of translocation time
has a transition from long-tailed distribution to Gaussian distribution with
increasing . rapidly decreases and then almost saturates with
increasing binding energy for short chain, however, it has a minimum for longer
chains at lower chaperone concentration. We also show that has a minimum
as a function of the chaperone concentration. For different , a
nonuniversal dependence of on the chain length is also observed.
These results can be interpreted by characteristic entropic effects for
flexible polymers induced by either crowding effect from high chaperone
concentration or the intersegmental binding for the high binding energy.Comment: 10 pages, to appear in J. Am. Chem. So
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