8,967 research outputs found
Decoding the `Nature Encoded' Messages for Distributed Energy Generation Control in Microgrid
The communication for the control of distributed energy generation (DEG) in
microgrid is discussed. Due to the requirement of realtime transmission, weak
or no explicit channel coding is used for the message of system state. To
protect the reliability of the uncoded or weakly encoded messages, the system
dynamics are considered as a `nature encoding' similar to convolution code, due
to its redundancy in time. For systems with or without explicit channel coding,
two decoding procedures based on Kalman filtering and Pearl's Belief
Propagation, in a similar manner to Turbo processing in traditional data
communication systems, are proposed. Numerical simulations have demonstrated
the validity of the schemes, using a linear model of electric generator dynamic
system.Comment: It has been submitted to IEEE International Conference on
Communications (ICC
Testing for Explosive Behaviour in Relative Inflation Measures: Implications for Monetary Policy
In this paper we test for large deviations in headline measures of the price level relative to core measures using the recently proposed test of Phillips et al. (2011a). We find evidence of explosive behaviour in the headline price index of personal consumption expenditures (PCE) relative to the core PCE (less food and energy prices) on three occasions from 1982-2010. Two of these episodes correspond to energy supply shocks (OPEC price collapse of 1986 and Hurricane Katrina). The third one is during March 2008 through September 2008 which seems to be driven by both food and energy prices as these indices exhibit explosive behaviour. We also find evidence suggesting that inflation expectations behave differently under normal and explosive periods. In particular, unemployment and interest rates also help predict inflation expectations during explosive episodes relative to normal times. Furthermore, explosive episodes in the relative measure between headline and core inflation is found to be more important than the relative volatile periods implied by a Markov-switching model when studying inflation expectations. The findings of this paper suggest that explosive behaviour of headline versus core PCE should be taken into account when conducting monetary policy as it is a key determinant in consumers’ inflation expectations.Explosive behaviour, core inflation, relative measure, inflation expectations
The curious morphology and orientation of Orion proplyd HST-10
HST-10 is one of the largest proplyds in the Orion Nebula and is located
approximately 1' SE of the Trapezium. Unlike other proplyds in Orion, however,
the long-axis of HST-10 does not align with theta 1 C Ori, but is instead
aligned with the rotational axis of the HST-10 disk. This cannot be easily
explained using current photo-evaporation models. In this letter, we present
high spatial resolution near-infrared images of the Orion proplyd HST-10 using
Keck/NIRC2 with the Laser Guide Star Adaptive Optics system, along with
multi-epoch analysis of HH objects near HST-10 using Hubble Space Telescope
WFPC2 and ACS cameras. Our narrow-band near-IR images resolve the proplyd
ionization front (IF) and circumstellar disk down to 23 AU at the distance to
Orion in Br gamma, He I, H_2, and PAH emission. Br gamma and He I emission
primarily trace the IF (with the disk showing prominently in silhouette), while
the H_2 and PAH emission trace the surface of the disk itself. PAH emission
also traces small dust grains within the proplyd envelope which is asymmetric
and does not coincide with the IF. The curious morphology of the PAH emission
may be due to UV-heating by both theta 1C Ori and theta 2A Ori. Multi-epoch HST
images of the HST-10 field show proper motion of 3 knots associated with HH
517, clearly indicating that HST-10 has a jet. We postulate that the
orientation of HST-10 is determined by the combined ram-pressure of this jet
and the FUV-powered photo-ablation flow from the disk surface.Comment: 12 pages, 2 figures. Accepted for publication in ApJ Letters, 4 Nov
201
First Science Observations with SOFIA/FORCAST: 6 TO 37 micron Imaging of Orion BN/KL
The BN/KL region of the Orion Nebula is the nearest region of high mass star
formation in our galaxy. As such, it has been the subject of intense
investigation at a variety of wavelengths, which have revealed it to be
brightest in the infrared to sub-mm wavelength regime. Using the newly
commissioned SOFIA airborne telescope and its 5-40 micron camera FORCAST,
images of the entire BN/KL complex have been acquired. The 31.5 and 37.1 micron
images represent the highest resolution observations (<=4") ever obtained of
this region at these wavelengths. These observations reveal that the BN object
is not the dominant brightness source in the complex at wavelengths >31.5
microns, and that this distinction goes instead to the source IRc4. It was
determined from these images and derived dust color temperature maps that IRc4
is also likely to be self-luminous. A new source of emission has also been
identified at wavelengths >31.5 microns that coincides with the northeastern
outflow lobe from the protostellar disk associated with radio source I.Comment: 6 pages, 3 figures, accepted for publication in ApJ
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