22,591 research outputs found
Using film cutting in interface design
It has been suggested that computer interfaces could be made more usable if their designers utilized cinematography techniques, which have evolved to guide
the viewer through a narrative despite frequent discontinuities in the presented scene (i.e., cuts between shots). Because of differences between the domains of
film and interface design, it is not straightforward to understand how such techniques can be transferred. May and Barnard (1995) argued that a psychological
model of watching film could support such a transference. This article presents an extended account of this model, which allows identification of the practice of collocation
of objects of interest in the same screen position before and after a cut. To verify that filmmakers do, in fact, use such techniques successfully, eye movements
were measured while participants watched the entirety of a commerciall
Florida's West Coast inlets: shoreline effects and recommended action
This report responds to the 1986 Beaches Bill which, in recognition of the
potential deleterious impact on Florida's beaches of inlets modified for navigation,
mandated a study of those inlets with identification of recommended action to reduce
the impacts. This report addresses west Coast inlets; East Coast inlets are the
subject of a companion report.
There are 37 inlets along that portion of Florida's West Coast commencing from
Pensacola Bay Entrance to Caxambas Pass at the south end of Marco Island. Compared to
those on the East Coast, most West Coast inlets have not had the deleterious effects
on the adjacent beaches, yet all modified inlets without proper management have the
potential of impacting unfavorably on the adjacent shorelines. Moreover, at present
there is interest in opening three West Coast entrances which either have been open
in the past (Midnight Pass) or which have opened occasionally (Navarre Pass and
Entrance to Phillips Lake).
A review of inlets in their natural condition demonstrates the presence of a
shallow broad outer bar across which the longshore transport Occurs. These shallow
and shifting bar features were unsuitable for navigation which in many cases has led
to the deepening of the channels and fixing with one or two jetty structures. Inlets in this modified state along with inappropriate maintenance practices have the
potential of placing great ero$ional stress along the adjacent beaches. Moreover.
channel dredging can reduce wave sheltering of the shoreline by ebb tidal shoals and
alter the equilibrium of the affected shoreline segments. The ultimate in poor sand
management practice is the placement of good quality beach sand in water depths too
great for the sand to reenter the longshore system under natural forces; depths of 12
ft. or less are considered appropriate for Florida in order to maintain the sand in
the system.
With the interference of the nearshore sediment transport processes by inlets
modified for navigation, if the adjacent beaches are to be stabilized there must be
an active monitoring program with commitment to placement of dredged material of
beach quality on shoreline segments of documented need. Several East Coast inlets
have such transfer facilities; however. the quantities of sand transferred should be
increased. Although an evolution and improvement in the technical capability to
manage sand resources in the vicinity of inlets is expected, an adequate capability
exists today and a concerted program should be made to commence a scheduled
implementation of this capability at those entrances causing greatest erosional
stress on the adjacent shorelines.
A brief summary review for each of the 37 West Coast inlets is presented
including: a scaled aerial photograph, brief historical information, several items
related to sediment losses at each inlet and special characteristics relevant to
State responsibilities. For each inlet, where appropriate, the above infor~tion is
utilized to develop a recommenced action. (PDF has 101 pages.
Phonons in potassium doped graphene: the effects of electron-phonon interactions, dimensionality and ad-atom ordering
Graphene phonons are measured as a function of electron doping via the
addition of potassium adatoms. In the low doping regime, the in-plane carbon
G-peak hardens and narrows with increasing doping, analogous to the trend seen
in graphene doped via the field-effect. At high dopings, beyond those
accessible by the field-effect, the G-peak strongly softens and broadens. This
is interpreted as a dynamic, non-adiabatic renormalization of the phonon
self-energy. At dopings between the light and heavily doped regimes, we find a
robust inhomogeneous phase where the potassium coverage is segregated into
regions of high and low density. The phonon energies, linewidths and tunability
are remarkably similar for 1-4 layer graphene, but significantly different to
doped bulk graphite.Comment: Accepted in Phys. Rev. B as a Rapid Communication. 5 pages, 3
figures, revised text with additional dat
Thermal Casimir drag in fluctuating classical fields
A uniformly moving inclusion which locally suppresses the fluctuations of a
classical thermally excited field is shown to experience a drag force which
depends on the dynamics of the field. It is shown that in a number of cases the
linear friction coefficient is dominated by short distance fluctuations and
takes a very simple form. Examples where this drag can occur are for stiff
objects, such as proteins, nonspecifically bound to more flexible ones such as
polymers and membranes.Comment: 4 pages RevTex, 2 figure
Diffusion of active tracers in fluctuating fields
The problem of a particle diffusion in a fluctuating scalar field is studied.
In contrast to most studies of advection diffusion in random fields we analyze
the case where the particle position is also coupled to the dynamics of the
field. Physical realizations of this problem are numerous and range from the
diffusion of proteins in fluctuating membranes and the diffusion of localized
magnetic fields in spin systems. We present exact results for the diffusion
constant of particles diffusing in dynamical Gaussian fields in the adiabatic
limit where the field evolution is much faster than the particle diffusion. In
addition we compute the diffusion constant perturbatively, in the weak coupling
limit where the interaction of the particle with the field is small, using a
Kubo-type relation. Finally we construct a simple toy model which can be solved
exactly.Comment: 13 pages, 1 figur
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