Institution
Philips
Company•Vantaa, Finland•
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.
Papers published on a yearly basis
Papers
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02 May 2008TL;DR: In this article, the authors proposed to increase a surface area of one or more heat-dissipating elements proximate a trajectory of air flow through the fixture, resulting in a high air-flow rate.
Abstract: LED-based lighting fixtures suitable for general illumination in surface-mount or suspended installations, in which heat dissipation properties of the fixtures are significantly improved by decreasing thermal resistance between LED junctions and the ambient air. In various examples, improved heat dissipation is accomplished by increasing a surface area of one or more heat-dissipating elements proximate a trajectory of air flow through the fixture. In one aspect, various structural components of the fixtures are particularly configured to create and maintain a “chimney effect” within the fixture, resulting in a high air-flow rate, natural convection cooling system capable of efficiently dissipating the waste heat from the fixture without active cooling.
246 citations
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TL;DR: This work claims to be the first method to reliably measure SpO2 remotely during significant subject motion using the new ratio-of-ratios measurement principle, i.e. that the optimal signature remains the same when the SNR of the PPG signal drops significantly due to motion or limited measurement area.
Abstract: Finger-oximeters are ubiquitously used for patient monitoring in hospitals worldwide. Recently, remote measurement of arterial blood oxygenation (SpO2) with a camera has been demonstrated. Both contact and remote measurements, however, require the subject to remain static for accurate SpO2 values. This is due to the use of the common ratio-of-ratios measurement principle that measures the relative pulsatility at different wavelengths. Since the amplitudes are small, they are easily corrupted by motion-induced variations. We introduce a new principle that allows accurate remote measurements even during significant subject motion. We demonstrate the main advantage of the principle, i.e. that the optimal signature remains the same even when the SNR of the PPG signal drops significantly due to motion or limited measurement area. The evaluation uses recordings with breath-holding events, which induce hypoxemia in healthy moving subjects. The events lead to clinically relevant SpO2 levels in the range 80–100%. The new principle is shown to greatly outperform current remote ratio-of-ratios based methods. The mean-absolute SpO2-error (MAE) is about 2 percentage-points during head movements, where the benchmark method shows a MAE of 24 percentage-points. Consequently, we claim ours to be the first method to reliably measure SpO2 remotely during significant subject motion.
246 citations
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TL;DR: An ultrasonic human-blood-flow velocity profile measurement method using time-domain correlation of consecutive echo pairs has been developed and the interdependencies of window length, beam width, vessel diameter, and viewing angle are evaluated.
Abstract: An ultrasonic human-blood-flow velocity profile measurement method using time-domain correlation of consecutive echo pairs has been developed. The time shift between a pair of range gated echoes is estimated by searching for the shift that results in the maximum correlation. The time shift indicates the distance a group of scatterers has moved, from which flow velocity is estimated. The basis for the computer simulations and error analyses of the scheme includes a band-passed white Gaussian noise signal model for an echo from a scattering medium, the estimate of flow velocity from both a single scatterer and multiple scatterers, and a derived precision estimation. The error analysis via computer simulation includes an evaluation of errors associated with the correlation method. For a uniform flow velocity profile, beamwidth modulation represents the greatest error source. However, for a nonuniform flow velocity profile, the jitter caused by a small flow velocity gradient can exceed the other error sources. A detailed computer simulation evaluated the interdependencies of window length, beam width, vessel diameter, and viewing angle on the estimation of flow velocity. >
246 citations
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TL;DR: This work advances a general route for facile fabrication of thin-film devices from solution by incorporating a glass-inducing diluent that enables controlled crystallization from an initial vitreous state of the organic semiconductor, formed in a selected area of the phase diagram of the two constituents.
Abstract: Electronic devices based on single crystals of organic semiconductors provide powerful means for studying intrinsic charge-transport phenomena and their fundamental electronic limits1–4. However, for technological exploitation, it is imperative not to be confined to the tedious growth and cumbersome manipulation of molecular crystals—which generally show notoriously poor mechanical properties—but to be able to process such materials into robust architectures by simple and efficient means. Here, we advance a general route for facile fabrication of thin-film devices from solution. The key beneficial feature of our process—and the principal difference from existing vapour deposition5–7 and solution-processing schemes7–10—is the incorporation of a glass-inducing diluent that enables controlled crystallization from an initial vitreous state of the organic semiconductor, formed in a selected area of the phase diagram of the two constituents. We find that the vitrifying diluent does not adversely affect device performance. Indeed, our environmentally stable, discrete rubrene-based transistors rival amorphous silicon devices, reaching saturated mobilities of up to 0.7 cm2 V−1 s−1, ON–OFF ratios of ≥106 and subthreshold slopes as steep as 0.5 V per decade. A nearly temperature-independent device mobility, indicative of a high crystalline quality of our solution-processed, rubrene-based films11, corroborates these findings. Inverter and ring-oscillator structures are also demonstrated.
246 citations
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TL;DR: A novel error protection method that can provide adaptive quality-of-service (QoS) to layered coded video by utilizing priority queueing at the network layer and retry-limit adaptation at the link layer is proposed.
Abstract: Robust streaming of video over 802.11 wireless LANs (WLANs) poses many challenges, including coping with packets losses caused by network buffer overflow or link erasures. In this paper, we propose a novel error protection method that can provide adaptive quality-of-service (QoS) to layered coded video by utilizing priority queueing at the network layer and retry-limit adaptation at the link layer. The design of our method is motivated by the observation that the retry limit settings of the MAC layer can be optimized in such a way that the overall packet losses that are caused by either link erasure or buffer overflow are minimized. We developed a real-time retry limit adaptation algorithm to trace the optimal retry limit for both the single-queue (or single-layer) and multiqueue (or multilayer) cases. The video layers are unequally protected over the wireless link by the MAC with different retry limits. In our proposed transmission framework, these retry limits are dynamically adapted depending on the wireless channel conditions and traffic characteristics. Furthermore, the proposed priority queueing discipline is enhanced with packet filtering and purging functionalities that can significantly save bandwidth by discarding obsolete or un-decodable packets from the buffer. Simulations show that the proposed cross-layer protection mechanism can significantly improve the received video quality.
245 citations
Authors
Showing all 68268 results
Name | H-index | Papers | Citations |
---|---|---|---|
Mark Raymond Adams | 147 | 1187 | 135038 |
Dario R. Alessi | 136 | 354 | 74753 |
Mohammad Khaja Nazeeruddin | 129 | 646 | 85630 |
Sanjay Kumar | 120 | 2052 | 82620 |
Mark W. Dewhirst | 116 | 797 | 57525 |
Carl G. Figdor | 116 | 566 | 52145 |
Mathias Fink | 116 | 900 | 51759 |
David B. Solit | 114 | 469 | 52340 |
Giulio Tononi | 114 | 511 | 58519 |
Jie Wu | 112 | 1537 | 56708 |
Claire M. Fraser | 108 | 352 | 76292 |
Michael F. Berger | 107 | 540 | 52426 |
Nikolaus Schultz | 106 | 297 | 120240 |
Rolf Müller | 104 | 905 | 50027 |
Warren J. Manning | 102 | 606 | 38781 |