Philips

About: Philips is a company organization based out in Vantaa, Finland. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 68260 authors who have published 99663 publications receiving 1882329 citations. The organization is also known as: Koninklijke Philips Electronics N.V. & Royal Philips Electronics.

Energy-Efficient Distributed Spectrum Sensing for Cognitive Sensor Networks

Abstract: Reliability and energy consumption in detection are key objectives for distributed spectrum sensing in cognitive sensor networks. In conventional distributed sensing approaches, although the detection performance improves with the number of radios, so does the network energy consumption. We consider a combined sleeping and censoring scheme as an energy efficient spectrum sensing technique for cognitive sensor networks. Our objective is to minimize the energy consumed in distributed sensing subject to constraints on the detection performance, by optimally choosing the sleeping and censoring design parameters. The constraint on the detection performance is given by a minimum target probability of detection and a maximum permissible probability of false alarm. Depending on the availability of prior knowledge about the probability of primary user presence, two cases are considered. The case where a priori knowledge is not available defines the blind setup; otherwise the setup is called knowledge-aided. By considering a sensor network based on IEEE 802.15.4/ZigBee radios, we show that significant energy savings can be achieved by the proposed scheme.

Submillimeter three-dimensional coronary MR angiography with real-time navigator correction: comparison of navigator locations.

Abstract: Three-dimensional free-breathing coronary magnetic resonance angiography was performed in eight healthy volunteers with use of real-time navigator technology. Images acquired with the navigator localized at the right hemidiaphragm and at the left ventricle were objectively compared. The diaphragmatic navigator was found to be superior for vessel delineation of middle to distal portions of the coronary arteries.

121.9-Gb/s PDM-OFDM Transmission With 2-b/s/Hz Spectral Efficiency Over 1000 km of SSMF

Abstract: We discuss optical multi-band orthogonal frequency division multiplexing (OFDM) and show that by using multiple parallel OFDM bands, the required bandwidth of the digital-to-analogue/ analogue-to-digital converters and the required cyclic prefix can significantly be reduced. With the help of four OFDM bands and polarization division multiplexing (PDM) we report continuously detectable transmission of 10 times121.9-Gb/s (112.6-Gb/s without OFDM overhead) at 50-GHz channel spacing over 1,000-km standard single mode fiber (SSMF) without any inline dispersion compensation. In this experiment 8 QAM subcarrier modulation is used which confines the spectrum of the 121.9 Gb/s PDM-OFDM signal within a 22.8 GHz optical bandwidth. Moreover, we propose a digital signal processing method to reduce the matching requirements for the wideband transmitter IQ mixer structures required for PDM-OFDM.

Tri-color white light led lamp

Abstract: The invention relates to a tri-color lamp for generating white 1ight comprising a phosphor composition comprising a phosphor of general formula (Ba1-x-y-z-SrxCay)2SiO4:Euz, wherein 0 ≤ x ≤1, 0 ≤ y ≤1 and 0 < z < 1. The phosphor composition may also comprise a red phosphor. The two phosphors can absorb radiation emitted by a 1ight emitting diode, particularly a blue LED. This arrangement provides a mixing of three light sources -light emitted from the two phosphors and unabsorbed light from the LED. The invention also relates to an alternative to a green LED comprising a single green phosphor of general formula (Ba1-x-y-z-SrxCay)2SiO4:Euz, wherein 0 ≤ x ≤1, 0 ≤ y ≤1 and 0 < z < 1, that absorbs radiation from a blue LED. A resulting device provides green light of high absorption efficiency and high luminous equivalent va1ues.