12,771 research outputs found
Multiple Transactions Model: A Panel Data Approach to Estimate Housing Market Indices
In this paper, a multiple transactions model with a panel data approach is used to estimate housing market indices. The multiple transactions model keeps the same features of the repeat transactions index model (i.e., tracking the price appreciation of same houses). However, the multiple transactions model overcomes the shortcomings of the repeat transactions model by avoiding the correlated error terms. The indicative empirical analysis on a small sample of actual house transaction data demonstrates that the proposed multiple transactions model is superior to the repeat transactions model in terms of index variance, robustness of estimate, index revision volatility, and out-of-sample prediction of individual house prices.
Anyon Wave Function for the Fractional Quantum Hall Effect
An anyon wave function (characterized by the statistical factor )
projected onto the lowest Landau level is derived for the fractional quantum
Hall effect states at filling factor ( and are
integers). We study the properties of the anyon wave function by using detailed
Monte Carlo simulations in disk geometry and show that the anyon ground-state
energy is a lower bound to the composite fermion one.Comment: Reference adde
Machine Learning for Soft Robot Sensing and Control: A Tutorial Study
Developing feedback controllers for robots with embedded sensors is challenging and typically requires expert knowledge. As machine learning (ML) advances, the development of learning-based controllers has become more and more accessible, even to non-experts. This work presents the development of a tutorial to educate non-roboticists about ML-based sensing and control in cyber-physical systems using a soft robotic device. We demonstrated this by creating a recurrent neural network-based closed-loop force controller for a soft finger with embedded soft sensors. Our hypothesis is validated in a 2.5-hour workshop session for students with no prior knowledge of robot control. This work serves as a tutorial for participants aiming to experience and perform a general benchmark for soft robot control tasks, with little or even no expertise in robotics
Rapidly variable Fe K line in NGC 4051
We present a detailed analysis on the variability of the Fe K emission line
in NGC 4051 using ASCA data. Through simple Gaussian line fits, we find not
only obvious Fe K line variability with no significant difference in the X-ray
continuum flux between two ASCA observations which were separated by 440
days, but also rapid variability of Fe K line on time scales s
within the second observation. During the second observation, the line is
strong (EW = 733 eV) and broad (
keV) when the source is brightest, and become weaker (EW = 165
eV) and narrower ( keV) whilst the source is weakest. The
equivalent width of Fe K line correlates positively with the continuum flux,
which shows an opposite trend with another Seyfert 1 galaxy MCG --6-30-15.Comment: 12 pages with 5 figures, to appear in ApJ Vol. 516, L6
Traumatic Brain Injury in the Elderly: Is it as Bad as we Think?
Traumatic brain injury in elderly patients is a neglected global disease burden. The main cause is fall, followed by motor vehicle accidents. This review article summarizes different aspects of geriatric traumatic brain injury, including epidemiology, pathology, and effects of comorbidities and pre-injury medications such as antiplatelets and anticoagulants. Functional outcome with or without surgical intervention, cognitive outcome, and psychiatric complications are discussed. Animal models are also reviewed in attempt to explain the relationship of aging and outcome, together with advances in stem cell research. Though elderly people in general did fare worse after traumatic brain injury, certain âyounger elderlyâ people, aged 65â75Â years, could have a comparable outcome to younger adults after minor to moderate head injury
The charged-hadron/pion ratio at the Relativistic Heavy Ion Collider
The hadron/pion ratio is calculated in 200 GeV AuAu collisions at
midrapidity, applying pQCD and non-universal transverse-momentum broadening.
Arguments are presented for such non-universality, and the idea is implemented
in a model, which explains the enhancement of the hadron/pion ratio in central
AuAu collisions. The model also describes the qualitative difference between
the recently-measured dAu nuclear enhancement factors for pions and charged
hadrons.Comment: 4 pages, 3 figure
Intrinsic response time of graphene photodetectors
Graphene-based photodetectors are promising new devices for high-speed
optoelectronic applications. However, despite recent efforts, it is not clear
what determines the ultimate speed limit of these devices. Here, we present
measurements of the intrinsic response time of metal-graphene-metal
photodetectors with monolayer graphene using an optical correlation technique
with ultrashort laser pulses. We obtain a response time of 2.1 ps that is
mainly given by the short lifetime of the photogenerated carriers. This time
translates into a bandwidth of ~262 GHz. Moreover, we investigate the
dependence of the response time on gate voltage and illumination laser power
Nuclear Effects on Heavy Boson Production at RHIC and LHC
We predict W and Z transverse momentum distributions from proton-proton and
nuclear collisions at RHIC and LHC. A resummation formalism with power
corrections to the renormalization group equations is used. The dependence of
the resummed QCD results on the non-perturbative input is very weak for the
systems considered. Shadowing effects are discussed and found to be unimportant
at RHIC, but important for LHC. We study the enhancement of power corrections
due to multiple scattering in nuclear collisions and numerically illustrate the
weak effects of the dependence on the nuclear mass.Comment: 21 pages, 11 figure
Photo-Thermoelectric Effect at a Graphene Interface Junction
We investigate the optoelectronic response of a graphene interface junction,
formed with bilayer and single-layer graphene, by photocurrent (PC) microscopy.
We measure the polarity and amplitude of the PC while varying the Fermi level
by tuning a gate voltage. These measurements show that the generation of PC is
by a photo-thermoelectric effect. The PC displays a factor of ~10 increase at
the cryogenic temperature as compared to room temperature. Assuming the
thermoelectric power has a linear dependence on the temperature, the inferred
graphene thermal conductivity from temperature dependent measurements has a
T^{1.5} dependence below ~100 K, which agrees with recent theoretical
predictions
- âŠ