715 research outputs found
Weighted spatiotemporal filtering using principal component analysis for analyzing regional GNSS position time series
Shape predominant effect in pattern recognition of geometric figures of rhesus monkey
AbstractThree monkeys were trained successively with discrimination, concurrent matching to sample, and sameness–difference judgment tasks in which learning curves were compared. Then, the display duration for the stimuli was shortened to 100, 50, and 30 ms respectively to test the changes in accuracy and reaction time. All results in three experimental paradigms suggested consistently that the geometric shape (triangle, circle, and square) plays a more predominant role than topological features (the hole inside of a figure and the hole numbers) in monkey figure recognition. The results are different from the experiment by human subjects who presented hole predominant in figure recognition. Therefore, the precedence in perception depends on subject species, stimulus set, and ecological significance of the perceiving process
China and the Fifth Estate: Net Delusion or Democratic Potential?
Arguably, liberal democratic societies are seeing the emergence of a ‘Fifth Estate’ that is being enabled by the Internet. This new organizational form is comparable to, but potentially more powerful than, the Fourth Estate, which developed as a significant force in an earlier period with an independent press and other mass media. While the significance of the press and the Internet to democratic governance is questioned in all societies, there is particular skepticism of their relevance outside the most liberal democratic regimes, which have a relatively free press and more pluralistic political systems, such as in North America and West Europe. Nevertheless, there have been vivid examples of where networked individuals have appeared to assert greater communicative power in the politics of governance, the media and everyday life, even in non-liberal democratic regimes, such as Hong Kong, and in some cases, China. This potential points to the need for more systematic empirical research in a wider variety of economic and political settings worldwide, particularly in states in which the Internet might offer a potential for more democratic governance and greater accountability of government controlled media. This paper examines cases in which networked individuals in China used the Internet to hold governmental and press institutions more accountable. The cases provide support for the relevance of the Fifth Estate concept in China, and also illuminates the process – showing how the Internet can be used to empower networked individuals in more autocratic regimes
Population dynamics under demographic and environmental stochasticity
The present paper is devoted to the study of the long term dynamics of
diffusion processes modelling a single species that experiences both
demographic and environmental stochasticity. In our setting, the long term
dynamics of the diffusion process in the absence of demographic stochasticity
is determined by the sign of , the external Lyapunov exponent, as
follows:
implies convergence to a unique positive stationary distribution . If
the system is of size for small (the
intensity of demographic stochasticity), demographic effects will make the
extinction time finite almost surely. This suggests that to understand the
dynamics one should analyze the quasi-stationary distribution (QSD)
of the system. The existence and uniqueness of the QSD is
well-known under mild assumptions.
We look at what happens when the population size is sent to infinity, i.e.,
when . We show that the external Lyapunov exponent still plays a
key role: 1) If , then , the mean
extinction time is of order and the extinction rate associated
with the QSD has a lower bound of order
; 2) If , then ,
the mean extinction time is polynomial in and the
extinction rate is polynomial in . Furthermore, when
we are able to show that the system exhibits multiscale dynamics:
at first the process quickly approaches the QSD and then, after
spending a polynomially long time there, it relaxes to the extinction state. We
give sharp asymptotics in for the time spent close to
.Comment: 59 page
The Dynamics of Public Attention to Online Disaster Information
This study explored the dynamics of public attention to online news on disappearance of Malaysia Airlines Flight 370 (MH370). Results revealed that increase of public attention to news has a leading effect on media attention. Moreover, public attention is influenced by daily news pressure, square of timelines, news topic, nationality of media organizations. In addition, public’ interest in news content is different in various phases of the disappearance. In the early aftermath, public purse news on stakeholder responses, and then public attention focus shift to disaster survey. Finally, news on stakeholder responses and disaster relief attracts more public attention
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