92,045 research outputs found
The Aga Khan University (International) in the United Kingdom Institute for the Study of Muslim Civilisations : recognition scheme for educational oversight : review
Vision-model-based Real-time Localization of Unmanned Aerial Vehicle for Autonomous Structure Inspection under GPS-denied Environment
UAVs have been widely used in visual inspections of buildings, bridges and
other structures. In either outdoor autonomous or semi-autonomous flights
missions strong GPS signal is vital for UAV to locate its own positions.
However, strong GPS signal is not always available, and it can degrade or fully
loss underneath large structures or close to power lines, which can cause
serious control issues or even UAV crashes. Such limitations highly restricted
the applications of UAV as a routine inspection tool in various domains. In
this paper a vision-model-based real-time self-positioning method is proposed
to support autonomous aerial inspection without the need of GPS support.
Compared to other localization methods that requires additional onboard
sensors, the proposed method uses a single camera to continuously estimate the
inflight poses of UAV. Each step of the proposed method is discussed in detail,
and its performance is tested through an indoor test case.Comment: 8 pages, 5 figures, submitted to i3ce 201
Active control transport design criteria
Vehicle design considerations for active control applications to subsonic transports are examined. Active control is defined along with those functions which are considered in the study of design criteria. The FAA regulations governing transport aircraft design are briefly discussed
03-03 "Reconciling Growth and Environment"
Macroeconomic theory and policy are strongly based on the assumption that economic growth is a fundamental goal. The environmental realities of the twenty- first century compel a reassessment of macro theory in terms of the impact of current growth patterns on planetary ecosystems.This paper examines the macroeconomic impacts of growth in terms of several major areas of conflict between economic demands and ecosystem capacities:
Fluorescence visualization of a convective instability which modulates the spreading of volatile surface films
The spontaneous spreading of a thin liquid film along the surface of a deep liquid layer of higher surface tension is a ubiquitous process which provides rapid and efficient surface transport of organic or biological material. For a source of constant concentration, the leading edge of a nonvolatile, immiscible film driven to spread by gradients in surface tension is known to advance as t^3/4 in time. Recent experiments using laser shadowgraphy to detect the advancing front of spreading films indicate, however, that immiscible but volatile sources of constant concentration spread with a reduced exponent according to t^1/2. Using a novel technique whereby fluorescent lines are inscribed in water, we have detected the evolution of a thermal instability beneath the leading edge of volatile films which strongly resembles a Rayleigh-BĂ©nard roll. We propose that the increased dissipation from this rotational flow structure is likely responsible for the reduction in spreading exponent. This observation suggests a conceptual framework for coupling the effects of evaporation to the dynamics of spreading
Coherent energy migration in solids: Determination of the average coherence length in oneâdimensional systems using tunable dye lasers
The coherent nature of energy propagation in solids at low temperatures was established from the time resolved response of the crystal to short optical pulses obtained from a dye laser (pumped by a nitrogen gas laser). The trapping and detrapping of the energy by shallow defects (x traps) was evident in the spectra and enabled us to extract the coherence length: lâł700 Ă
=186 molecules for the oneâdimensional triplet excitons of 1,2,4,5âtetrachlorobenzene crystals at T<4.2° K. This length which clearly exceeds the stochastic random walk limit is related to the thermalization mechanisms in this coupled excitonâtrap system, and its magnitude supports the notion that excitonâphonon coupling is responsible for the loss of coherence on very long molecular chains (trap concentration is 1/256â000)
Rule Managed Reporting in Energy Controlled Wireless Sensor Networks
This paper proposes a technique to extend the network lifetime of a wireless sensor network, whereby each sensor node decides its network involvement, based on energy resources and the information in each message (ascertained through a system of rules). Results obtained from the simulation of an industrial monitoring scenario have shown that a considerable increase in the lifetime and connectivity can be obtained
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