arXiv subjects

Timo Korhonen

Publications and source records attributed to Timo Korhonen.

4 recordsLinked to original sources

arXiv2024

CrowdEgress: A Multi-Agent Simulation Platform for Pedestrian Crowd

This article introduces a simulation platform to study complex crowd behavior in social context. The agent-based model is extended based on the social force model, and it mainly describes how agents interact with each other, and also with surrounding facilities such as walls, doors and exits. The simulation platform is compatible to FDS+Evac, and the input data in FDS+Evac could be imported into our simulation platform to create single-floor compartment geometry, and a flow solver is used to generate the roadmap towards exits. Most importantly, we plan to integrate advanced social and psychological theory into our simulation platform, especially investigating human behavior in emergency evacuation,such as pre-evacuation behavior, exit-selection activities, social group and herding effect and so forth.

physics.soc-ph↗

arXiv2022

Simulation of Crowd Egress with Environmental Stressors

This article introduces a modeling framework to characterize evacuee response to environmental stimuli during emergency egress. The model is developed in consistency with stress theory, which explains how an organism reacts to environmental stressors (e.g., alarm signals or hazardous factors such as smoke and fire). We integrate the theory into the well-known social force model, and develop a framework to simulate crowd evacuation behavior in multi-compartment buildings. Our method serves as a theoretical basis to study crowd movement at bottlenecks, and simulate their herding behavior and way-finding activities in normal and hazardous conditions. The pre-movement behavior is also investigated by using opinion dynamics with a social group model. The algorithms have been partly tested in FDS+EVAC as well as our simulation platform crowdEgress.

physics.soc-ph↗

arXiv2001

Timing system of the Swiss Light Source

The timing system of the Swiss Light Source is based on the event system concept of APS, Argonne [1]. However, for SLS the hardware was completely redesigned while preserving the software compatibility with the APS system. This gave us a head start in the implementation: we could use the latest available hardware and take advantage of the features integrated in the EPICS software. The event system is used as the sole timing distribution method, for hardware trigger delivery (assisted with a high-precision delay at a few places) and for controlling all the timing-related tasks of operation: injector sequencing, filling patterns, software synchronization, timestamps and so on. The event network is also extended to the beamlines to allow synchronization of the beamline experiments. The implementation consists of the hardware (Gigabit Ethernet link, FPGAs) and a firmware core written in VHDL. The functionality of the cards can be modified in situ by rewriting the firmware in flash memory. On the other hand, the functionality can be easily ported to new hardware architectures, allowing smooth upgrade paths and maximal reusability of the soft- and hardware resources. [1] F.R.Lenkszus et.al., 'The Advanced Photon Source Event System', Proc. ICALEPCS'95

physics.acc-ph↗

arXiv1999

Development of a Laser Wire Beam Profile Monitor (I)

A conceptual design work and a basic experimental study of a new beam profile monitor have been performed. The monitor will be used to measure emittance of an electron beam in the ATF damping ring at KEK, in which the transverse beam size of about 10 micron is expected. It utilizes a CW laser and an optical cavity, instead of a material wire, to minimize interference with an electron beam. A laser beam with a very thin waist is realized by employing the cavity of nearly concentric mirror configuration while the intensity is amplified by adjusting the cavity length to a Fabry-Perot resonance condition. We built a test cavity to establish a method to measure important parameters such as a laser beam waist and a power enhancement factor. Three independent methods were examined for the measurement of the beam waist. It was found that the cavity realized the beam waist of 20 micron with the power enhancement factor of 50.

hep-ex↗