628 research outputs found
Saving Human Lives: What Complexity Science and Information Systems can Contribute
We discuss models and data of crowd disasters, crime, terrorism, war and
disease spreading to show that conventional recipes, such as deterrence
strategies, are often not effective and sufficient to contain them. Many common
approaches do not provide a good picture of the actual system behavior, because
they neglect feedback loops, instabilities and cascade effects. The complex and
often counter-intuitive behavior of social systems and their macro-level
collective dynamics can be better understood by means of complexity science. We
highlight that a suitable system design and management can help to stop
undesirable cascade effects and to enable favorable kinds of self-organization
in the system. In such a way, complexity science can help to save human lives.Comment: 67 pages, 25 figures; accepted for publication in Journal of
Statistical Physics [for related work see http://www.futurict.eu/
Neural models of inter-cortical networks in the primate visual system for navigation, attention, path perception, and static and kinetic figure-ground perception
Vision provides the primary means by which many animals distinguish foreground objects from their background and coordinate locomotion through complex environments. The present thesis focuses on mechanisms within the visual system that afford figure-ground segregation and self-motion perception. These processes are modeled as emergent outcomes of dynamical interactions among neural populations in several brain areas. This dissertation specifies and simulates how border-ownership signals emerge in cortex, and how the medial superior temporal area (MSTd) represents path of travel and heading, in the presence of independently moving objects (IMOs).
Neurons in visual cortex that signal border-ownership, the perception that a border belongs to a figure and not its background, have been identified but the underlying mechanisms have been unclear. A model is presented that demonstrates that inter-areal interactions across model visual areas V1-V2-V4 afford border-ownership signals similar to those reported in electrophysiology for visual displays containing figures defined by luminance contrast. Competition between model neurons with different receptive field sizes is crucial for reconciling the occlusion of one object by another. The model is extended to determine border-ownership when object borders are kinetically-defined, and to detect the location and size of shapes, despite the curvature of their boundary contours.
Navigation in the real world requires humans to travel along curved paths. Many perceptual models have been proposed that focus on heading, which specifies the direction of travel along straight paths, but not on path curvature. In primates, MSTd has been implicated in heading perception. A model of V1, medial temporal area (MT), and MSTd is developed herein that demonstrates how MSTd neurons can simultaneously encode path curvature and heading. Human judgments of heading are accurate in rigid environments, but are biased in the presence of IMOs. The model presented here explains the bias through recurrent connectivity in MSTd and avoids the use of differential motion detectors which, although used in existing models to discount the motion of an IMO relative to its background, is not biologically plausible. Reported modulation of the MSTd population due to attention is explained through competitive dynamics between subpopulations responding to bottom-up and top- down signals
Towards A Computational Intelligence Framework in Steel Product Quality and Cost Control
Steel is a fundamental raw material for all industries. It can be widely used in vari-ous fields, including construction, bridges, ships, containers, medical devices and cars. However, the production process of iron and steel is very perplexing, which consists of four processes: ironmaking, steelmaking, continuous casting and rolling. It is also extremely complicated to control the quality of steel during the full manufacturing pro-cess. Therefore, the quality control of steel is considered as a huge challenge for the whole steel industry. This thesis studies the quality control, taking the case of Nanjing Iron and Steel Group, and then provides new approaches for quality analysis, manage-ment and control of the industry.
At present, Nanjing Iron and Steel Group has established a quality management and control system, which oversees many systems involved in the steel manufacturing. It poses a high statistical requirement for business professionals, resulting in a limited use of the system. A lot of data of quality has been collected in each system. At present, all systems mainly pay attention to the processing and analysis of the data after the manufacturing process, and the quality problems of the products are mainly tested by sampling-experimental method. This method cannot detect product quality or predict in advance the hidden quality issues in a timely manner. In the quality control system, the responsibilities and functions of different information systems involved are intricate. Each information system is merely responsible for storing the data of its corresponding functions. Hence, the data in each information system is relatively isolated, forming a data island. The iron and steel production process belongs to the process industry. The data in multiple information systems can be combined to analyze and predict the quality of products in depth and provide an early warning alert. Therefore, it is necessary to introduce new product quality control methods in the steel industry. With the waves of industry 4.0 and intelligent manufacturing, intelligent technology has also been in-troduced in the field of quality control to improve the competitiveness of the iron and steel enterprises in the industry. Applying intelligent technology can generate accurate quality analysis and optimal prediction results based on the data distributed in the fac-tory and determine the online adjustment of the production process. This not only gives rise to the product quality control, but is also beneficial to in the reduction of product costs. Inspired from this, this paper provide in-depth discussion in three chapters: (1) For scrap steel to be used as raw material, how to use artificial intelligence algorithms to evaluate its quality grade is studied in chapter 3; (2) the probability that the longi-tudinal crack occurs on the surface of continuous casting slab is studied in chapter 4;(3) The prediction of mechanical properties of finished steel plate in chapter 5. All these 3 chapters will serve as the technical support of quality control in iron and steel production
Crowd dynamics
Crowd dynamics are complex. This thesis examines the nature of the crowd
and its dynamics with specific reference to the issues of crowd safety. A model
(Legion) was developed that simulates the crowd as an emergent phenomenon using
simulated annealing and mobile cellular automata. We outline the elements of that
model based on the interaction of four parameters: Objective, Motility, Constraint
and Assimilation. The model treats every entity as an individual and it can simulate
how people read and react to their environment in a variety of conditions. Which
allows the user to study a wide range of crowd dynamics in different geometries and
highlights the interactions of the crowd with their environment. We demonstrate that
the model runs in polynomial time and can be used to assess the limits of crowd
safety during normal and emergency egress.
Over the last 10 years there have been many incidents of crowd related
disasters. We highlight deficiencies in the existing guidelines relating to crowds. We
compare and contrast the model with the safety guidelines and highlight specific
areas where the guides may be improved. We demonstrate that the model is capable
of reproducing these dynamics without additional parameters, satisfying Occam's
Razor. The model is tested against known crowd dynamics from field studies,
including Wembley Stadium, Balham Station and the Hong Kong Jockey club. We
propose an alternative approach to assessing the dynamics of the crowd through the
use of the simulation and analysis of least effort behaviour. Finally we test the
model in a variety of applications where crowd related incidents warrant structural
alterations at client sites. We demonstrate that the model explains the variance in a
variety of field measurements, that it is robust and that it can be applied to future
designs where safety and crowd comfort are criteria for design and cost savings
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