8,409,029 research outputs found
DSN acquisition of Magellan high-rate telemetry data
The Magellan Project levied the stringent requirement of a 98 percent high-rate telemetry data capture rate on the Deep Space Network (DSN) during the Magellan Prime Mapping Mission. To meet this requirement, the DSN undertook extensive development of the DSN Telemetry System, as well as extensive DSN operation planning and test and training. In actuality, the DSN substantially exceeded the requirement by achieving a Prime Mapping Mission high-rate telemetry data capture rate of 99.14 percent. This article details the DSN telemetry system development, and DSN operations planning and test and training. In addition, the actual high-rate telemetry data outages are comprehensively presented and analyzed
Rate data encoder
An apparatus and technique for encoding rate data is described. The expected range of the rate data is determined and the data falling within that range is encoded by conventional digital techniques. If the data falls either below or above the range, the encoding is stopped and signals are transmitted indicating that the data is not within the expected range
High data rate systems for the future
Information systems in the next century will transfer data at rates that are much greater than those in use today. Satellite based communication systems will play an important role in networking users. Typical data rates; use of microwave, millimeter wave, or optical systems; millimeter wave communication technology; modulators/exciters; solid state power amplifiers; beam waveguide transmission systems; low noise receiver technology; optical communication technology; and the potential commercial applications of these technologies are discussed
Foreign Exchange Rate Expectations: Micro Survey Data
This paper analyzes the panel data of bi-weekly surveys, conducted by the Japan Center for International Finance, on the yen/dollar exchange rate expectations of forty-four institutions for two years. There are three major findings in this paper. First, market participants are found to be heterogeneous. There are significant "individual effects" in their expectation formation. Second, many institutions are found to violate the rational expectation hypothesis. Third, forecasts with long horizons showed less yen appreciation than those with short horizons. Cross-equation constraints implied by the consistencyof the forecast term structure are strongly rejected in the data.
Constraining Galileon gravity from observational data with growth rate
We studied the cosmological constraints on the Galileon gravity obtained from
observational data of the growth rate of matter density perturbations, the
supernovae Ia (SN Ia), the cosmic microwave background (CMB), and baryon
acoustic oscillations (BAO). For the same value of the energy density parameter
of matter , the growth rate in Galileon models is enhanced,
relative to the CDM case, because of an increase in Newton's constant.
The smaller is, the more growth rate is suppressed. Therefore,
the best fit value of in the Galileon model, based only the
growth rate data, is quite small. This is incompatible with the value of
obtained from the combination of SN Ia, CMB, and BAO data. On
the other hand, in the CDM model, the values of
obtained from different observational data sets are consistent. In the analysis
of this paper, we found that the Galileon model is less compatible with
observations than the CDM model. This result seems to be qualitatively
the same in most of the generalized Galileon models in which Newton's constant
is enhanced.Comment: 16 pages, 8 figures, 2 tables, Accepted for publication in Progress
of Theoretical Physic
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