12,663 research outputs found
Metropolitan Growth Policies and New Housing Supply: Evidence from Australia\u27s Capital Cities
This paper empirically examines the relationship between house price change, metropolitan growth policies, and new housing supply in Australia\u27s five major capital cities. Our hypothesis suggests capital cities with tighter regulations on new development will have fewer housing starts and price elasticities than those in less- regulated markets. The empirical procedure used in this paper utilises the Urban Growth Model of Housing Supply developed in Mayer and Somerville (2000a and 2000b) and employed in Zabel and Patterson (2006) by using quarterly data on housing approvals and house prices from 1996-2010. Data on metropolitan growth policies in Australia is borrowed from Hamnett and Kellett (2007). Preliminary findings indicate that new housing supply in Australian capital cities is elastic to housing price changes, as a one per cent increase in prices leads to an approximately 4-6 per cent increase in housing approvals over five quarters. While this indicates a properly functioning housing market, the estimated elasticity is about a third of other developed countries, such as the United States. Furthermore, the use of established growth policies, such as urban growth boundaries and urban consolidation, appears to have a greater impact on new housing approvals than adoption of new-style growth policies, such as development corporations and infrastructure levies. However, both types of policies decrease new housing supply
Photoionization cross section calculations for the halogen-like ions Kr and Xe
Photoionization cross sections calculations on the halogen-like ions; Kr
and Xe have been performed for a photon energy range from each ion
threshold to 15 eV, using large-scale close-coupling calculations within the
Dirac-Coulomb R-matrix approximation. The results from our theoretical work are
compared with recent measurements made at the ASTRID merged-beam set-up at the
University of Aarhus in Denmark and from the Fourier transform ion cyclotron
resonance (FT-ICR) trap method at the SOLEIL synchrotron radiation facility in
Saint-Aubin, France and the Advanced Light Soure (ALS). For each of these
complex ions our theoretical cross section results over the photon energy range
investigated are seen to be in excellent agreement with experiment. Resonance
energy positions and quantum defects of the prominent Rydberg resonances series
identified in the spectra are compared with experiment for these complex
halogen like-ions.Comment: Accepted for publicatio
Performance constraints and compensation for teleoperation with delay
A classical control perspective is used to characterize performance constraints and evaluate compensation techniques for teleoperation with delay. Use of control concepts such as open and closed loop performance, stability, and bandwidth yield insight to the delay problem. Teleoperator performance constraints are viewed as an open loop time delay lag and as a delay-induced closed loop bandwidth constraint. These constraints are illustrated with a simple analytical tracking example which is corroborated by a real time, 'man-in-the-loop' tracking experiment. The experiment also provides insight to those controller characteristics which are unique to a human operator. Predictive displays and feedforward commands are shown to provide open loop compensation for delay lag. Low pass filtering of telemetry or feedback signals is interpreted as closed loop compensation used to maintain a sufficiently low bandwidth for stability. A new closed loop compensation approach is proposed that uses a reactive (or force feedback) hand controller to restrict system bandwidth by impeding operator inputs
Adaptive Bayesian decision feedback equalizer for dispersive mobile radio channels
The paper investigates adaptive equalization of time dispersive mobile ratio fading channels and develops a robust high performance Bayesian decision feedback equalizer (DFE). The characteristics and implementation aspects of this Bayesian DFE are analyzed, and its performance is compared with those of the conventional symbol or fractional spaced DFE and the maximum likelihood sequence estimator (MLSE). In terms of computational complexity, the adaptive Bayesian DFE is slightly more complex than the conventional DFE but is much simpler than the adaptive MLSE. In terms of error rate in symbol detection, the adaptive Bayesian DFE outperforms the conventional DFE dramatically. Moreover, for severely fading multipath channels, the adaptive MLSE exhibits significant degradation from the theoretical optimal performance and becomes inferior to the adaptive Bayesian DFE
K-shell x-ray spectroscopy of atomic nitrogen
Absolute {\it K}-shell photoionization cross sections for atomic nitrogen
have been obtained from both experiment and state-of-the-art theoretical
techniques. Due to the difficulty of creating a target of neutral atomic
nitrogen, no high-resolution {\it K}-edge spectroscopy measurements have been
reported for this important atom. Interplay between theory and experiment
enabled identification and characterization of the strong
resonance features throughout the threshold region. An experimental value
of 409.64 0.02 eV was determined for the {\it K}-shell binding energy.Comment: 4 pages, 2 graphs, 1 tabl
PSR J0737-3039B: A probe of radio pulsar emission heights
In the double pulsar system PSR J0737-3039A/B the strong wind produced by
pulsar A distorts the magnetosphere of pulsar B. The influence of these
distortions on the orbital-dependent emission properties of pulsar B can be
used to determine the location of the coherent radio emission generation region
in the pulsar magnetosphere. Using a model of the wind-distorted magnetosphere
of pulsar B and the well defined geometrical parameters of the system, we
determine the minimum emission height to be ~ 20 neutron star radii in the two
bright orbital longitude regions. We can determine the maximum emission height
by accounting for the amount of deflection of the polar field line with respect
to the magnetic axis using the analytical magnetic reconnection model of Dungey
and the semi-empirical numerical model of Tsyganenko. Both of these models
estimate the maximum emission height to be ~ 2500 neutron star radii. The
minimum and maximum emission heights we calculate are consistent with those
estimated for normal isolated pulsars.Comment: 29 pages, 14 figures, Accepted by ApJ on 3 March 201
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