• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4355-4374
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• 2018

Crowd escape event detection has become one of the hottest problems in intelligent surveillance filed. When the 'escape event' occurs, pedestrians will escape in a disordered way with different velocities and directions. Based on these characteristics, this paper proposes a Direction-Collectiveness Model to detect escape event in crowd scenes. First, we extract a set of trajectories from video sequences by using generalized Kanade-Lucas-Tomasi key point tracker (gKLT). Second, a Direction-Collectiveness Model is built based on the randomness of velocity and orientation calculated from the trajectories to express the movement of the crowd. This model can describe the movement of the crowd adequately. To obtain a generalized crowd escape event detector, we adopt an adaptive threshold according to the Direction-Collectiveness index. Experiments conducted on two widely used datasets demonstrate that the proposed model can detect the escape events more effectively from dense crowd.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.1
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• pp.47-53
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• 2022

The escape behavior of prey fish to predator attack is directly linked to the survival of the fish. In this study, I explored the escape behavior of Medaka fish to bird attacks. To simulate the attack, I designed a model triangular-shaped bird to slide along a fishing line connected between rods at both ends of the tank. The triangular shape was set to 10×15 (S=1), 15×20 (S=2), and 20×25 cm (S=3) with base×height. The slope (θ) of the fishing line, which determines the attack speed of the model bird, was set to values of 15° (θ=1), 30° (θ=2), and 45° (θ=3). The escape behavior was characterized using five variables: escape speed (ν), escape acceleration (α), responsiveness (γ), branch length similarity entropy (ε), and alignment (ϕ). The experimental results showed when (S, θ)=(fixed, varied), the change in values of the five variables were not significant. Thus, the fish respond more sensitively to S than to θ In contrast, when (S, θ)=(varied, fixed), ν, α, and γ showed increasing trends but ε and ϕ did not change much. This indicates the nature of fish escape behavior irrespective of the threat is inherent in ε and ϕ. I found that fish escape behavior can be divided into two types for the five physical quantities. In particular, the analysis showed that the type was mainly determined by the size of the model bird.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.5
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• pp.1-7
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• 2009

Escape distance and escape barrier are critical elements for the quantitative evaluation of escape safety. Through theoretical demonstration and modeling in precedent studies, they have been analyzed for their generality and applicability. To make more practical evaluation method, we should quantitatively analyze the influence of each barrier and escape condition on escape safety considering various barriers in escaping routes. In this study, to develop more accurate and applicable escape analysis model, we have focused on three research methods as below: First, we derived quantified function to predict various escape barriers in escaping routes by theoretical analyses of the escape barriers and conditions. Second, we substituted the derived quantified function for an evaluation tool of escape safety suggested by precedent studies. Third, we examined applicability and feasibility of the developed method by modeling with the consideration of the escape conditions and barriers.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.306-312
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• 2001

In this research, we are trying to develop a framework to evaluate the prevention program for Tsunami disaster based on the Multi-agent simulation model. Tsunami has arisen by the earthquake. It happened after flew minutes or few hours when it occurred. It is clear that Tsunami will come after earthquake and from seashore. If we prevent the damage by Tsunami, we should make people who is in the seashore and lived near the seaside escape from there. Moreover we must forecast the escape activity from Tsunami. Former research of this field, some researches try to forecast the escape activity as macro level. However, people who escape from Tsunami is differ from their physical ability and ability of information processing. It needs a more accuracy model to forecast the escape activity of them. Furthermore they make a decision step by step using the various information. Therefore escape activity from Tsunami will describe using an agent based model which can only treat the information processing of human being. In this paper, we develop the evacuation model from Tsunami disaster using the Multi agent based model. The purpose of this study is to analyze the human action pattern when Tsunami occurred, and to make an accurately assessment for damages by Tsunami. The Fujisawa city government is planning and operating the various prevention program far Tsunami. However nobody assess it, because they do not have any simulation models for Tsunami disaster. If they want to set an effective prevention program for Tsunami, they should have any kinds of simulation model. The results of this study are 1) To develop the Multi agent based evacuees escape activity model. 2) Assess the damage of Tsunami in Fujisawa-City.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.193-198
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• 2022

In this study, for the purpose of reducing the catch of small giant octopus in a net pot, an escape experiment of octopus was performed on five types of escape rings of different sizes. As a result of the experiment, the smallest giant octopus with a weight of 406 g was found to escape from an escape ring with a diameter of 30 mm or larger, and 592 g octopus, a weight similar to the octopus of the current minimum landing weight (600 g), escaped from an escape ring with a diameter of larger than 40 mm. An individual weight with 406 g becomes 39 mm when converted from a diameter of 25 mm circular escape vent; that is, the circumference to the inner diameter of the mesh. It can be inferred that the converted mesh size of 39 mm cannot escape. Logistic regression analysis was performed using a generalized linear model (GLM) to investigate the correlation between the ratio of escape ring size/Mantle diameter (R/MD) and the escape rate. As a result, it was found that there was a significant correlation between the R/MD ratio and the escape rate and that the higher the R/MD ratio, the greater the escape rate. As a result of logistic regression analysis, the R/MD value was denoted 0.520 with the 50% escape rate. In addition, it can be estimated to be about 50 mm when converted to the mesh size. Therefore, in this study, the diameter of the escape ring and the size of the escape possible of the octopus were experimentally considered. It was found that there was a significant correlation.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.135-140
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• 2001

In the last years there have been some severe accidents with passenger vessels. So, International Maritime Organization(IMO) has recognized that computer stimulation of the evacuation may be required for passenger vessels. Human elements is a key issues of escape analysis on shipboard. There are technical requirements to simulate of escape analysis for human elements. Technical requirements include model of ship structure, evacuation algorithm, human behaviour analysis and influence of ship listing/motion. This paper provides the key issues and technologies of simulation for human escape on shipboard.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.2
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• pp.115-125
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• 2010

In order to design the optimal escape vent for the coon strip shrimp pot, the tank experiments were conducted with the model pot of five different slit height and slit width, respectively. The optimal height and width of escape vent were determined to 20mm and 40mm by tank experiments, respectively. These were determined by the 50% selection carapace length which was denoted to 25mm in selectivity curve. The escape experiments were conducted to determine a number of escape vent with the original shrimp pot to be set the designed escape vent from 2 vents to 10 vents increasing at intervals of 2 vents in tank. The optimal number of escape vents denoted 8 vents. Therefore, to apply the escape vent in commercial shrimp pot will be efficient to reduce small size shrimps to catch.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2977-2983
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• 2023

During normal operation, some parts of the fission product in the defective fuel rods can release into the primary loops in PWR and the escape rate coefficients are widely used to assess quantitatively the release behaviors of fission products in the industry. The escape rate coefficients have been standardized and have been validated by some drilling experiments before the 1970s. In the paper, the model to determine the escape rate coefficients of fission products has been established and the typical escape rate coefficients of noble gas and iodine have been deduced based on the measured radiochemical data in one operating PWR. The result shows that the apparent escape rate coefficients vary with the release-to-birth and decay constants for different fission products of the same element. In addition, it is found that the escape rate coefficients from the defective rod with large defects are much higher than the standard escape rate coefficients, i.e., averagely 4.4 times and 1.8 times for noble gas and iodine respectively. The enhanced release of fission products from the severe secondary hydriding of several defective fuel rods in one cycle may lead to the potential risk of the temporary shutdown of the operating reactors.

• Journal of Magnetics
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• v.7 no.4
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• pp.156-159
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• 2002

We have investigated the escape rate of nano-magnetic particle with a magnetic field applied along the easy axis. The model studied here is described by the Hamiltonian H=$K_1\hat{S}{_z^2}$ ＋ $K_2\hat{S}{_y^2}$ ＋ $g{\mu}_bB$ $\hat{S}_x(K_1>K_2>0)$ and the escape rate was calculated with in the semiclassical approximation. We have obtained a diagram for orders of the phase transition depending on the anisotropy constant and the external field. For $K_2$/$K_1>$0.85 the present model reveals the existence of the first order transition within the quantum regime.

• Journal of Ecology and Environment
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• v.31 no.2
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• pp.89-95
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• 2008

Sensing the approach of a predator is critical to the survival of prey, especially when the prey has no choice but to escape at a precisely timed moment. Escape behavior has been approached from both proximate and ultimate perspectives. On the proximate level, empirical research about electrophysiological mechanisms for detecting predators has focused on vision, an important modality that helps prey to sense approaching danger. Studies of looming-sensitive neurons in locusts are a good example of how the selective sensitivity of nervous systems towards specific targets, especially approaching objects, has been understood and realistically modeled in software and robotic systems. On the ultimate level, general optimality models have provided an evolutionary framework by considering costs and benefits of visually elicited escape responses. A recent paper showed how neural network models can be used to understand the evolution of visually mediated antipredatory behaviors. We discuss this new trend towards integration of these relatively disparate approaches, the proximate and the ultimate perspectives, for understanding of the evolution of behavior of predators and prey. Focusing on one of the best-studied escape pathway models, the Orthopteran LGMD/DCMD pathway, we discuss how ultimate-level optimality modeling can be integrated with proximate-level studies of escape behaviors in animals.