Showing papers by "Philips published in 2006"

Mesh network personal emergency response appliance

Abstract: A monitoring system includes one or more wireless nodes forming a wireless mesh network; a user activity sensor including a wireless mesh transceiver adapted to communicate with the one or more wireless nodes using the wireless mesh network; and a digital monitoring agent coupled to the wireless transceiver through the wireless mesh network to request assistance from a third party based on the user activity sensor.

Perfusion-CT Assessment of Infarct Core and Penumbra Receiver Operating Characteristic Curve Analysis in 130 Patients Suspected of Acute Hemispheric Stroke

Abstract: Background and Purpose— Different definitions have been proposed to define the ischemic penumbra from perfusion-CT (PCT) data, based on parameters and thresholds tested only in small pilot studies. The purpose of this study was to perform a systematic evaluation of all PCT parameters (cerebral blood flow, volume [CBV], mean transit time [MTT], time-to-peak) in a large series of acute stroke patients, to determine which (combination of) parameters most accurately predicts infarct and penumbra. Methods— One hundred and thirty patients with symptoms suggesting hemispheric stroke ≤12 hours from onset were enrolled in a prospective multicenter trial. They all underwent admission PCT and follow-up diffusion-weighted imaging/fluid-attenuated inversion recovery (DWI/FLAIR); 25 patients also underwent admission DWI/FLAIR. PCT maps were assessed for absolute and relative reduced CBV, reduced cerebral blood flow, increased MTT, and increased time-to-peak. Receiver-operating characteristic curve analysis was performe...

Molecular machines: nanomotor rotates microscale objects.

Abstract: A molecular motor in a liquid-crystal film uses light to turn items thousands of times larger than itself.

IEEE 802.22: An Introduction to the First Wireless Standard based on Cognitive Radios

Abstract: In November/2004, we witnessed the formation of the first worldwide effort to define a novel wireless air interface (i.e., MAC and PHY) standard based on Cognitive Radios (CRs): the IEEE 802.22 Working Group (WG). The IEEE 802.22 WG is chartered with the development of a CR-based Wireless Regional Area Network (WRAN) Physical (PHY) and Medium Access Control (MAC) layers for use by license-exempt devices in the spectrum that is currently allocated to the Television (TV) service. Since 802.22 is required to reuse the fallow TV spectrum without causing any harmful interference to incumbents (i.e., the TV receivers), cognitive radio techniques are of primary importance in order to sense and measure the spectrum and detect the presence/absence of incumbent signals. On top of that, other advanced techniques that facilitate coexistence such as dynamic spectrum management and radio environment characterization could be designed. In this paper, we provide a detailed overview of the 802.22 draft specification, its architecture, requirements, applications, and coexistence considerations. These not only form the basis for the definition of this groundbreaking wireless air interface standard, but will also serve as foundation for future research in the promising area of CRs.

Towards molecular electronics with large-area molecular junctions

Abstract: The use of molecular electronics is a much-discussed alternative to conventional silicon devices: the prospect of such tiny components has obvious implications for miniaturization. One approach is to replace the conventional semiconductor with a single molecular layer that self-organizes between two electrodes. Molecular tunnel junctions have been made in such systems, but they tend to be hard to reproduce, unstable and limited to small diameters. Now Akkerman et al. have developed a relatively simple way of producing stable, reproducible molecular junctions with large areas from self-assembled monolayers of alkanethiols. The process is compatible with standard integrated circuit technologies and could offer a cheap way forward in the quest for practical molecular electronics. A relatively simple method to fabricate stable, reproducible molecular junctions with large areas from self-assembled monolayers of alkanethiols has been developed — this approach could offer a cheap and promising way forward for molecular electronics. Electronic transport through single molecules has been studied extensively by academic1,2,3,4,5,6,7,8 and industrial9,10 research groups. Discrete tunnel junctions, or molecular diodes, have been reported using scanning probes11,12, break junctions13,14, metallic crossbars6 and nanopores8,15. For technological applications, molecular tunnel junctions must be reliable, stable and reproducible. The conductance per molecule, however, typically varies by many orders of magnitude5. Self-assembled monolayers (SAMs) may offer a promising route to the fabrication of reliable devices, and charge transport through SAMs of alkanethiols within nanopores is well understood, with non-resonant tunnelling dominating the transport mechanism8. Unfortunately, electrical shorts in SAMs are often formed upon vapour deposition of the top electrode16,17,18, which limits the diameter of the nanopore diodes to about 45 nm. Here we demonstrate a method to manufacture molecular junctions with diameters up to 100 µm with high yields (> 95 per cent). The junctions show excellent stability and reproducibility, and the conductance per unit area is similar to that obtained for benchmark nanopore diodes. Our technique involves processing the molecular junctions in the holes of a lithographically patterned photoresist, and then inserting a conducting polymer interlayer between the SAM and the metal top electrode. This simple approach is potentially low-cost and could pave the way for practical molecular electronics.

A 13.56-MHz RFID System Based on Organic Transponders

Abstract: RFID tags based on organic transistors are described, discussing in detail the IC blocks used to build the logic and the radio. Tags energized and read out at 13.56 MHz, de facto standard frequency for item-level identification, have been tested and enabled for the first time multiple-object identification, using different 6-bit codes. A complete 64-bit transponder, the most complex organic RFID tag reported to date, operates at 125 kHz and employs 1938 transistors

Read-proof hardware from protective coatings

Abstract: In cryptography it is assumed that adversaries only have black box access to the secret keys of honest parties. In real life, however, the black box approach is not sufficient because attackers have access to many physical means that enable them to derive information on the secret keys. In order to limit the attacker’s ability to read out secret information, the concept of Algorithmic Tamper Proof (ATP) security is needed as put forth by Gennaro, Lysyanskaya, Malkin, Micali and Rabin. An essential component to achieve ATP security is read-proof hardware. In this paper, we develop an implementation of read-proof hardware that is resistant against invasive attacks. The construction is based on a hardware and a cryptographic part. The hardware consists of a protective coating that contains a lot of randomness. By performing measurements on the coating a fingerprint is derived. The cryptographic part consists of a Fuzzy Extractor that turns this fingerprint into a secure key. Hence no key is present in the non-volatile memory of the device. It is only constructed at the time when needed, and deleted afterwards. A practical implementation of the hardware and the cryptographic part is given. Finally, experimental evidence is given that an invasive attack on an IC equipped with this coating, reveals only a small amount of information on the key.

Liver fibrosis: non‐invasive assessment with MR elastography

Abstract: The aim of this study was to assess the feasibility of using non-invasive MR elastography for determining the stage of liver fibrosis. Twenty-five consecutive patients who had liver biopsy for suspicion of chronic liver disease were included in the study. The stage of fibrosis on the biopsies was assessed according to the METAVIR scoring system from F0, no fibrosis, to F4, cirrhosis. MR elastography was performed by transmitting low-frequency (65 Hz) mechanical waves into the liver with a transducer placed at the back of the patients. The MR pulse sequence was a motion-sensitized spin-echo sequence, phase-locked to the mechanical excitation. The phase maps were processed to obtain shear elasticity and shear viscosity maps. The mean hepatic shear elasticity increased with increasing stage of fibrosis. The mean elasticity was 2.24 +/- 0.23 kPa in the 11 patients without substantial fibrosis (F0-F1 grades), 2.56 +/- 0.24 kPa in the four patients with substantial fibrosis (F2-F3) and 4.68 +/- 1.61 kPa in the 10 patients with cirrhosis (F4). The differences between groups were statistically significant (p

Multiple Nose Region Matching for 3D Face Recognition under Varying Facial Expression

Abstract: An algorithm is proposed for 3D face recognition in the presence of varied facial expressions. It is based on combining the match scores from matching multiple overlapping regions around the nose. Experimental results are presented using the largest database employed to date in 3D face recognition studies, over 4,000 scans of 449 subjects. Results show substantial improvement over matching the shape of a single larger frontal face region. This is the first approach to use multiple overlapping regions around the nose to handle the problem of expression variation

Supercurrent reversal in quantum dots

Abstract: When two superconductors are electrically connected by a weak link--such as a tunnel barrier--a zero-resistance supercurrent can flow. This supercurrent is carried by Cooper pairs of electrons with a combined charge of twice the elementary charge, e. The 2e charge quantum is clearly visible in the height of voltage steps in Josephson junctions under microwave irradiation, and in the magnetic flux periodicity of h/2e (where h is Planck's constant) in superconducting quantum interference devices. Here we study supercurrents through a quantum dot created in a semiconductor nanowire by local electrostatic gating. Owing to strong Coulomb interaction, electrons only tunnel one-by-one through the discrete energy levels of the quantum dot. This nevertheless can yield a supercurrent when subsequent tunnel events are coherent. These quantum coherent tunnelling processes can result in either a positive or a negative supercurrent, that is, in a normal or a pi-junction, respectively. We demonstrate that the supercurrent reverses sign by adding a single electron spin to the quantum dot. When excited states of the quantum dot are involved in transport, the supercurrent sign also depends on the character of the orbital wavefunctions.

PSP: An Advanced Surface-Potential-Based MOSFET Model for Circuit Simulation

Abstract: This paper describes the latest and most advanced surface-potential-based model jointly developed by The Pennsylvania State University and Philips. Specific topics include model structure, mobility and velocity saturation description, further development and verification of symmetric linearization method, recent advances in the computational techniques for the surface potential, modeling of gate tunneling current, inclusion of the retrograde impurity profile, and noise sources. The emphasis of this paper is on incorporating the recent advances in MOS device physics and modeling within the compact modeling context

Cellular effect of high doses of silica-coated quantum dot profiled with high throughput gene expression analysis and high content cellomics measurements

Abstract: Quantum dots (Qdots) are now used extensively for labeling in biomedical research, and this use is predicted to grow because of their many advantages over alternative labeling methods. Uncoated Qdots made of core/shell CdSe/ZnS are toxic to cells because of the release of Cd2+ ions into the cellular environment. This problem has been partially overcome by coating Qdots with polymers, poly(ethylene glycol) (PEG), or other inert molecules. The most promising coating to date, for reducing toxicity, appears to be PEG. When PEG-coated silanized Qdots (PEG-silane-Qdots) are used to treat cells, toxicity is not observed, even at dosages above 10−20 nM, a concentration inducing death when cells are treated with polymer or mercaptoacid coated Qdots. Because of the importance of Qdots in current and future biomedical and clinical applications, we believe it is essential to more completely understand and verify this negative global response from cells treated with PEG-silane-Qdots. Consequently, we examined the mole...

Rapid online quantification of left ventricular volume from real-time three-dimensional echocardiographic data.

Abstract: Aims Determination of left ventricular (LV) volumes and ejection fraction (EF) from two-dimensional echocardiographic (2DE) images is subjective, time-consuming, and relatively inaccurate because of foreshortened views and the use of geometric assumptions Our aims were (1) to validate a new method for rapid, online measurement of LV volumes from real-time three-dimensional echocardiographic (RT3DE) data using cardiac magnetic resonance (CMR) as the reference and (2) to compare its accuracy and reproducibility with standard 2DE measurements Methods and results CMR, 2DE, and RT3DE datasets were obtained in 50 patients End-systolic and end-diastolic volumes (ESV and EDV) were calculated from the 2DE images using biplane method of disks ES and ED RT3DE datasets were analysed using prototype software designed to automatically detect the endocardial surface using a deformable shell model and calculate ESV and EDV from voxel counts 2DE and RT3DE-derived volumes were compared with CMR (linear regression, Bland–Altman analysis) In most patients, analysis of RT3DE data required <2 min per patient RT3DE measurements correlated highly with CMR ( r : 096, 097, and 093 for EDV, ESV, and EF, respectively) with small biases (−14 mL, −65 mL, −1%) and narrow limits of agreement (SD: 17 mL, 16 mL, 64%) 2DE measurements correlated less well with CMR ( r : 089, 092, 086) with greater biases (−23 mL, −15 mL, 1%) and wider limits of agreement (SD: 29 mL, 24 mL, 95%) RT3DE resulted in lower intra-observer (EDV: 79 vs 23%; ESV: 76 vs 26%) and inter-observer variability (EDV: 11 vs 26%; ESV: 13 vs 31%) Conclusion Semi-automated detection of the LV endocardial surface from RT3DE data is suitable for clinical use because it allows rapid, accurate, and reproducible measurements of LV volumes, superior to conventional 2DE methods

Accuracy of 16-row multidetector computed tomography for the assessment of coronary artery stenosis.

Abstract: ContextMultidetector computed tomography (MDCT) has been proposed as a noninvasive method to evaluate coronary anatomy.ObjectiveTo determine the diagnostic accuracy of 16-row MDCT for the detection of obstructive coronary disease based exclusively on quantitative analysis and performed in a multicenter study.Design, Setting, and PatientsEleven participating sites prospectively enrolled 238 patients who were clinically referred for nonemergency coronary angiography from June 2004 through March 2005. Following a low-dose MDCT scan to evaluate coronary artery calcium, 187 patients with an Agatston score of less than 600 underwent contrast-enhanced MDCT. Conventional angiography was performed 1 to 14 days after MDCT. Conventional angiographic and MDCT studies were analyzed by independent core laboratories.Main Outcome MeasuresSegment-based and patient-based sensitivities and specificities for the detection of luminal stenosis of more than 50% (of luminal diameter) and more than 70% (of luminal diameter) based on quantitative coronary angiography.ResultsOf 1629 nonstented segments larger than 2 mm in diameter, there were 89 (5.5%) in 59 (32%) of 187 patients with stenosis of more than 50% by conventional angiography. Of the 1629 segments, 71% were evaluable on MDCT. After censoring all nonevaluable segments as positive, the sensitivity for detecting more than 50% luminal stenoses was 89%; specificity, 65%; positive predictive value, 13%; and negative predictive value, 99%. In a patient-based analysis, the sensitivity for detecting patients with at least 1 positive segment was 98%; specificity, 54%; positive predictive value, 50%; and negative predictive value, 99%. After censoring all nonevaluable segments as positive, the sensitivity for detecting more than 70% luminal stenoses was 94%; specificity, 67%; positive predictive value, 6%; and negative predictive value, 99%. In a patient-based analysis, the sensitivity for detecting patients with at least 1 positive segment was 94%; specificity, 51%; positive predictive value, 28%; and negative predictive value, 98%.ConclusionsThe results of this study indicate that MDCT coronary angiography performed with 16-row scanners is limited by a high number of nonevaluable cases and a high false-positive rate. Thus, its routine implementation in clinical practice is not justified. Nevertheless, given its high sensitivity and negative predictive value, 16-row MDCT may be useful in excluding coronary disease in selected patients in whom a false-positive or inconclusive stress test result is suspected.

Throughput Analysis of Synchronous Data Flow Graphs

Abstract: Synchronous Data Flow Graphs (SDFGs) are a useful tool for modeling and analyzing embedded data flow applications, both in a single processor and a multiprocessing context or for application mapping on platforms. Throughput analysis of these SDFGs is an important step for verifying throughput requirements of concurrent real-time applications, for instance within design-space exploration activities. Analysis of SDFGs can be hard, since the worst-case complexity of analysis algorithms is often high. This is also true for throughput analysis. In particular, many algorithms involve a conversion to another kind of data flow graph, the size of which can be exponentially larger than the size of the original graph. In this paper, we present a method for throughput analysis of SDFGs, based on explicit state-space exploration and we show that the method, despite its worst-case complexity, works well in practice, while existing methods often fail. We demonstrate this by comparing the method with state-ofthe- art cycle mean computation algorithms. Moreover, since the state-space exploration method is essentially the same as simulation of the graph, the results of this paper can be easily obtained as a byproduct in existing simulation tools.

Choosing governance modes for external technology sourcing

Abstract: This study examines the effect of uncertainty on governance mode choice of interfirm relationships in new business development (NBD). We combine transaction cost economics and real options reasoning, arguing that in the early stages of NBD, where technological and market uncertainty are very high, companies are better off using governance modes that are reversible and involve a low level of commitment. When uncertainty has decreased as a result of prior R&D investments, transaction costs considerations become dominant and companies will shift towards governance modes that are less reversible and more hierarchical. We argue that technological distance leads to less hierarchical governance modes and prior cooperation between firms leads to subsequent choices for more hierarchical modes. Finally, we propose that higher exogenous uncertainty leads to less hierarchical governance modes.

Temperature‐Stable Dielectrics Based on Chemically Inhomogeneous BaTiO3

Abstract: The dielectric properties and chemical homogeneity of BaTiO3 ceramics sintered with additions of the pseudophase “CdBi2Nb2O9” were investigated using SEM, TEM, STEM, and EDX. In materials showing the “X7R” dielectric temperature characteristic, the microstructure exhibits the grain core-grain shell structure. The perovskite material in the shell shows a temperature characteristic determined by mixed crystals of BaTiO3 with the complex perovskites Ba(Bi1/2Nb1/2)O3 and Ba(Cd1/3Nb2/3)O3 having an approximate Curie point of -80°C. The chemical inhomogeneity emerges during a process of reactive liquid-phase sintering. Application of too-high sintering temperatures leads to uniform distributions of the additives via solid-state diffusion and to the loss of the X7R characteristic.

RFID-Tags for anti-counterfeiting

Abstract: RFID-tags are becoming very popular tools for identification of products. As they have a small microchip on board, they offer functionality that can be used for security purposes. This chip functionality makes it possible to verify the authenticity of a product and hence to detect and prevent counterfeiting. In order to be successful for these security purposes too, RFID-tags have to be resistant against many attacks, in particular against cloning of the tag. In this paper, we investigate how an RFID-tag can be made unclonable by linking it inseparably to a Physical Unclonable Function (PUF). We present the security protocols that are needed for the detection of the authenticity of a product when it is equipped with such a system. We focus on off-line authentication because it is very attractive from a practical point of view. We show that a PUF based solution for RFID-tags is feasible in the off-line case.

Liquid Crystal Display Device and Method for Fabricating the Same

Abstract: A liquid crystal display (LCD) device includes an array substrate; a gate line formed on the array substrate; a data line formed on the array substrate crossing the gate lines; a thin film transistor formed on the array substrate, the thin film transistor being formed at an intersection between the gate line and the data line; a pixel electrode formed on the array substrate and connected to the thin film transistor; an insulating interlayer formed on an entire surface of the array substrate; a common electrode formed on the insulating interlayer and having a plurality of slits; a metal line formed on the insulating interlayer overlapping the data line and the common electrode; a color filter substrate attached to the array substrate; and a liquid crystal layer formed between the array substrate and the color filter substrate.

Three-dimensional radial ultrashort echo-time imaging with T2 adapted sampling.

Abstract: The application of 3D radial sampling of the free-induction decay to proton ultrashort echo-time (UTE) imaging is reported. The effects of T2 decay during signal acquisition on the 3D radial point-spread function are analyzed and compared to 2D radial and 1D sampling. It is found that in addition to the use of ultrashort TE, the proper choice of the acquisition-window duration TAQ is essential for imaging short-T2 components. For 3D radial sampling, a maximal signal-to-noise ratio (SNR) with negligible decay-induced loss in spatial resolution is obtained for an acquisition-window duration of TAQ ≈ 0.69 T2. For 2D and 1D sampling, corresponding values are derived as well. Phantom measurements confirm the theoretical findings and demonstrate the impact of different acquisition-window durations on SNR and spatial resolution for a given T2 component. In vivo scans show the potential of 3D UTE imaging with T2-adapted sampling for musculoskeletal imaging using standard MR equipment. The visualization of complex anatomy is demonstrated by extracting curved slices from the isotropically resolved 3D UTE image data. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc.

Metal artifact reduction in CT using tissue-class modeling and adaptive prefiltering.

Abstract: High-density objects such as metal prostheses, surgical clips, or dental fillings generate streak-like artifacts in computed tomography images. We present a novel method for metal artifact reduction by in-painting missing information into the corrupted sinogram. The information is provided by a tissue-class model extracted from the distorted image. To this end the image is first adaptively filtered to reduce the noise content and to smooth out streak artifacts. Consecutively, the image is segmented into different material classes using a clustering algorithm. The corrupted and missing information in the original sinogram is completed using the forward projected information from the tissue-class model. The performance of the correction method is assessed on phantom images. Clinical images featuring a broad spectrum of metal artifacts are studied. Phantom and clinical studies show that metal artifacts, such as streaks, are significantly reduced and shadows in the image are eliminated. Furthermore, the novel approach improves detectability of organ contours. This can be of great relevance, for instance, in radiation therapy planning, where images affected by metal artifacts may lead to suboptimal treatment plans.

Methods and apparatus for high power factor controlled power delivery using a single switching stage per load

Abstract: Methods and apparatus for high power factor power transfer to a load using a single switching stage. In exemplary implementations, a controllable variable power may be delivered to a load using a single switching stage while maintaining high power factor, in some cases without requiring any feedback information relating to the load conditions (i.e., without monitoring load voltage and/or current) to control normal switching operations in the single switching stage, and without requiring regulation of load voltage and/or load current. In one example, a single stage high power factor driver is used to control power delivery to an LED-based light source.