354 research outputs found
MINNESOTA PRODUCTION AND CONSUMPTION FORECAST OF MAJOR FEED GRAINS BY MINNESOTA COUNTY FOR 1990 AND 2000
Crop Production/Industries,
Effects of Boundary Conditions on Single-File Pedestrian Flow
In this paper we investigate effects of boundary conditions on one
dimensional pedestrian flow which involves purely longitudinal interactions.
Qualitatively, stop-and-go waves are observed under closed boundary condition
and dissolve when the boundary is open. To get more detailed information the
fundamental diagrams of the open and closed systems are compared using
Voronoi-based measurement method. Higher maximal specific flow is observed from
the pedestrian movement at open boundary condition
Generalized Centrifugal Force Model for Pedestrian Dynamics
A spatially continuous force-based model for simulating pedestrian dynamics
is introduced which includes an elliptical volume exclusion of pedestrians. We
discuss the phenomena of oscillations and overlapping which occur for certain
choices of the forces. The main intention of this work is the quantitative
description of pedestrian movement in several geometries. Measurements of the
fundamental diagram in narrow and wide corridors are performed. The results of
the proposed model show good agreement with empirical data obtained in
controlled experiments.Comment: 10 pages, 14 figures, accepted for publication as a Regular Article
in Physical Review E. This version contains minor change
Exploring the Effect of Crowd Management Measures on Passengers’ Behaviour at Metro Stations
To reduce problems of interaction at the platform train interface (PTI) platform edge doors (PEDs) and markings on the platform are used as door positions indicators. The common methods to study the effect of these measures are based on average values of density using Fruin’s Level of Service (LOS), however identification cannot be made of which part of the PTI is more congested. To solve this problem, a new method is proposed. The method included a conceptual model in which the PTI was discretised into 40 cm square cells to identify which part of the platform is more congested. Passengers’ behaviour was recorded considering two situations before the train arrives: i) passengers waiting in front of the doors; ii) passengers waiting beside the doors. Observation was done at existing stations at Metro de Santiago and London Underground. Results show that PEDs changed the behaviour of passengers as they were located beside the doors rather than in front of them. In addition, when markings were used on the platform, then this behaviour was reinforced. Therefore, it is recommended to use this method to better design the PTI rather than the LOS which is used to design the whole platform. Further research is needed to study the effect of PEDs on passengers with reduced mobility
The Fundamental Diagram of Pedestrian Movement Revisited
The empirical relation between density and velocity of pedestrian movement is
not completely analyzed, particularly with regard to the `microscopic' causes
which determine the relation at medium and high densities. The simplest system
for the investigation of this dependency is the normal movement of pedestrians
along a line (single-file movement). This article presents experimental results
for this system under laboratory conditions and discusses the following
observations: The data show a linear relation between the velocity and the
inverse of the density, which can be regarded as the required length of one
pedestrian to move. Furthermore we compare the results for the single-file
movement with literature data for the movement in a plane. This comparison
shows an unexpected conformance between the fundamental diagrams, indicating
that lateral interference has negligible influence on the velocity-density
relation at the density domain . In addition we test a
procedure for automatic recording of pedestrian flow characteristics. We
present preliminary results on measurement range and accuracy of this method.Comment: 13 pages, 9 figure
Reanalysis of Data Taken by the CANGAROO 3.8 Meter Imaging Atmospheric Cherenkov Telescope: PSR B1706-44, SN 1006, and Vela
We have reanalyzed data from observations of PSR B1706-44, SN 1006, and the
Vela pulsar region made with the CANGAROO 3.8 m imaging atmospheric Cherenkov
telescope between 1993 and 1998 in response to the results reported for these
sources by the H.E.S.S. collaboration. In our reanalysis, in which gamma-ray
selection criteria have been determined exclusively using gamma-ray simulations
and OFF-source data as background samples, no significant TeV gamma-ray signals
have been detected from compact regions around PSR B1706-44 or within the
northeast rim of SN 1006. We discuss reasons why the original analyses gave the
source detections. The reanalysis did result in a TeV gamma-ray signal from the
Vela pulsar region at the 4.5 sigma level using 1993, 1994, and 1995 data. The
excess was located at the same position, 0.13 deg. to the southeast of the Vela
pulsar, as that reported in the original analysis. We have investigated the
effect of the acceptance distribution in the field of view of the 3.8 m
telescope, which rapidly decreases toward the edge of the field of the camera,
on the detected gamma-ray morphology. The expected excess distribution for the
3.8 m telescope has been obtained by reweighting the distribution of HESS
J0835-455 measured by H.E.S.S. with the acceptance of the 3.8 m telescope. The
result is morphologically comparable to the CANGAROO excess distribution,
although the profile of the acceptance-reweighted H.E.S.S. distribution is more
diffuse than that of CANGAROO. The integral gamma-ray flux from HESS J0835-455
has been estimated for the same region as defined by H.E.S.S. from the
1993-1995 data of CANGAROO to be F(> 4.0 +/- 1.6 TeV) = (3.28 +/- 0.92) x
10^{-12} photons cm^{-2} s^{-1}, which is statistically consistent with the
integral flux obtained by H.E.S.S.Comment: Published in ApJ, minor improvement
Making a journey in knowledge management strategy
This paper reports results from an ongoing project examining what managers think about knowledge management in the context of their organisation. This was done in a facilitated computerassisted group workshop environment. Here we compare the outcomes of workshops held for two relatively large UK organisations, one public sector and the other private. Our conclusions are that there are relatively few differences between the perceptions of these two groups of managers, and that these differences stem more from the stage of the knowledge management life cycle that the two organisations have reached, rather than from the difference in context between public and private sector. © iKMS & World Scientific Publishing Co
High-statistics modeling of complex pedestrian avoidance scenarios
Quantitatively modeling the trajectories and behavior of pedestrians walking
in crowds is an outstanding fundamental challenge deeply connected with the
physics of flowing active matter, from a scientific point of view, and having
societal applications entailing individual safety and comfort, from an
application perspective.
In this contribution, we review a pedestrian dynamics modeling approach,
previously proposed by the authors, aimed at reproducing some of the
statistical features of pedestrian motion. Comparing with high-statistics
pedestrian dynamics measurements collected in real-life conditions (from
hundreds of thousands to millions of trajectories), we modeled quantitatively
the statistical features of the undisturbed motion (i.e. in absence of
interactions with other pedestrians) as well as the avoidance dynamics
triggered by a pedestrian incoming in the opposite direction. This was
accomplished through (coupled) Langevin equations with potentials including
multiple preferred velocity states and preferred paths. In this chapter we
review this model, discussing some of its limitations, in view of its extension
toward a more complex case: the avoidance dynamics of a single pedestrian
walking through a crowd that is moving in the opposite direction. We analyze
some of the challenges connected to this case and present extensions to the
model capable of reproducing some features of the motion
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