14,737 research outputs found

    Modeling rationality to control self-organization of crowds: An environmental approach

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    In this paper we propose a classification of crowd models in built environments based on the assumed pedestrian ability to foresee the movements of other walkers. At the same time, we introduce a new family of macroscopic models, which make it possible to tune the degree of predictiveness (i.e., rationality) of the individuals. By means of these models we describe both the natural behavior of pedestrians, i.e., their expected behavior according to their real limited predictive ability, and a target behavior, i.e., a particularly efficient behavior one would like them to assume (for, e.g., logistic or safety reasons). Then we tackle a challenging shape optimization problem, which consists in controlling the environment in such a way that the natural behavior is as close as possible to the target one, thereby inducing pedestrians to behave more rationally than what they would naturally do. We present numerical tests which elucidate the role of rational/predictive abilities and show some promising results about the shape optimization problem

    Does financial development cause economic growth in the ASEAN-4 countries

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    This paper empirically examines the short- and long-run finance-growth nexus during the post-1997 financial crisis in the ASEAN-4 countries (i.e., Indonesia,Malaysia, Thailand and the Philippines) by employing battery of times series techniques such as autoregressive distributed lag (ARDL) model, vector error correction model (VECM), variance decompositions (VDCs) and impulseresponse functions (IRFs). Based on the ARDL models, the study documents a long-run equilibrium between economic growth, finance depth, share of investment and inflation. The study also finds that the common sources of economic progress/regress among the countries are price stability and financial development. Granger causality tests based on the VECM further reveals that there are: (i) no causality between finance-growth in Indonesia; the finding in favour of “the independent hypothesis” of Lucas (1988); (ii) a unidirectional causality running from finance to growth in Malaysia, thus supporting “the finance-growth led hypothesis” or “the supply-leading view”; (iii) a bidirectional causality between finance-growth in Thailand, the finding accords with “the feedback hypothesis” or “bidirectional causality view”; and (iv) a unidirectional causality stemming from growth to finance in the Philippines, the finding echoes with “the growth-led finance hypothesis” or “the demand following view” of Robinson (1952). Based on the VDCs and IRFs, the study discovers that the variations in the economic growth rely very much on its own innovations. If policy makers want to promote growth in the ASEAN-4 countries, priority should be given for long run policies, i.e., the enhancement of existing financial institutions both in the banking sector and stock market

    MHD Modeling for Formation Process of Coronal Mass Ejections: Interaction between Ejecting Flux Rope and Ambient Field

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    We performed magnetohydrodynamic simulation of a formation process of coronal mass ejections (CMEs), focusing on interaction (reconnection) between an ejecting flux rope and its ambient field. We examined three cases with different ambient fields: no ambient field, and cases with dipole field of two opposite directions which are parallel and anti-parallel to that of the flux rope surface. As a result, while the flux rope disappears in the anti-parallel case, in other cases the flux ropes can evolve to CMEs and show different amounts of rotation of the flux rope. The results imply that the interaction between an ejecting flux rope and its ambient field is an important process for determining CME formation and CME orientation, and also show that the amount and direction of magnetic flux within the flux rope and the ambient field are key parameters for CME formation. Especially, the interaction (reconnection) plays a significant role to the rotation of the flux rope, with a process similar to "tilting instability" in a spheromak-type experiment of laboratory plasma.Comment: 24 pages, 5 figures. Accepted for publication in Ap
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