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21.
A system for the automatic measurement of the circadian activity deviations in telemedicine has been developed within the framework of a "Health Integrated Smart Home Information System" (HIS2). HIS2 is an experimental platform for the evaluation and the development of technologies in order to ensure the security and quality of life for patients who need home based medical monitoring. Location sensors are placed in each room of the HIS2, allowing the monitoring of patient's successive activity phases within the patient's home environment. We proceeded with a sampling in an hourly schedule to detect weak rhythmic variations. Based on numerous measurements, we established a mean value with confidence limits. These also allowed us to define a zone within which the patient's activity is qualified to be "predictable." Alerts are set off if the patient's activity deviates from this zone.  相似文献   
22.
Recently Victor Shoup noted that there is a gap in the widely believed security result of OAEP against adaptive chosen-ciphertext attacks. Moreover, he showed that, presumably, OAEP cannot be proven secure from the one-wayness of the underlying trapdoor permutation. This paper establishes another result on the security of OAEP. It proves that OAEP offers semantic security against adaptive chosen-ciphertext attacks, in the random oracle model, under the partial-domain one-wayness of the underlying permutation. Therefore, this uses a formally stronger assumption. Nevertheless, since partial-domain one-wayness of the RSA function is equivalent to its (full-domain) onewayness, it follows that the security of RSA-OAEP can actually be proven under the sole RSA assumption, although the reduction is not tight.  相似文献   
23.
The conversion of low frequency noise into phase noise in microwave oscillators is studied through an analytical calculation of the pushing factor. This calculation is based on a simplified equivalent circuit for two types of active devices : field effect transistors (Fet) and heterojunction bipolar transistors (hbt). The preeminence in the conversion process of the gate- source capacitance in theFet and the base- emitter junction in thehbt is pointed out. Practical methods are proposed to reduce the phase noise in these circuits.  相似文献   
24.
Emerging communication paradigms like the cognitive radio require extremely flexible physical layer functional units that can be parameterized at runtime for supporting multiple modes. Parameterizing the hardware accelerators in the cognitive radio baseband incurs a latency penalty, which is a function of the amount of reconfiguration data required by the accelerators. In an opportunistic spectrum access scenario, the cumulative latency required to reconfigure all the physical layer units when switching to a new channel reduces the useful time available for transmission, leading to a lower system throughput. Against this background, this paper gives an overview of the amount of reconfiguration data required by different candidate accelerator architectures for performing the computationally intensive channelization function, in the digital front-end of the cognitive radio terminal. The paper also identifies opportunities for reusing hardwired stages of a channelization accelerator across multiple modes, while minimizing the reconfiguration overhead.  相似文献   
25.
This paper presents the insulated TO-220AB TRIAC package aging when these devices are subjected to experimental power cycling test with various case temperature swings (ΔTcase). This study includes reliability tests set-up, results and failure analysis. An innovative failure analysis flow is proposed to identify the failure mechanism implied. This new failure analysis process flow is necessary due to the complex stack of these devices. Finally, thanks to the reliability tests and the complete failure analysis results, the thermal resistance (Rth) change is correlated to the physical defect modification. This whole study gives the first data collection that is required to propose a lifetime prediction model for insulated TO-220AB TRIAC package during power cycling accelerated aging tests.  相似文献   
26.
The primary objective of this study was to develop a computer-aided method for the quantification of three-dimensional (3-D) cartilage changes over time in knees with osteoarthritis (OA). We introduced a local coordinate system (LCS) for the femoral and tibial cartilage boundaries that provides a standardized representation of cartilage geometry, thickness, and volume. The LCS can be registered in different data sets from the same patient so that results can be directly compared. Cartilage boundaries are segmented from 3-D magnetic resonance (MR) slices with a semi-automated method and transformed into offset-maps, defined by the LCS. Volumes and thickness are computed from these offset-maps. Further anatomical labeling allows focal volumes to be evaluated in predefined subregions. The accuracy of the automated behavior of the method was assessed, without any human intervention, using realistic, synthetic 3-D MR images of a human knee. The error in thickness evaluation is lower than 0.12 mm for the tibia and femur. Cartilage volumes in anatomical subregions show a coefficient of variation ranging from 0.11% to 0.32%. This method improves noninvasive 3-D analysis of cartilage thickness and volume and is well suited for in vivo follow-up clinical studies of OA knees.  相似文献   
27.
The high integration level associated to the increase of the operating frequency of microelectronic integrated circuits create complex electromagnetic coupling in the interconnection lines which lead to mismatch and frequency dispersion. In the present paper, we propose a full-wave analysis to characterise the electromagnetic behaviour of interconnection planar lines using mixed-potential integral equations technique. The theoretical and numerical treatments of Green’s functions for the specific structures are firstly presented. The calculated results for parallel and coplanar strips are compared to the published ones. The effect of the finite ground plane on the propagation constant and the characteristic impedance is then analysed for different permittivities. The obtained theoretical and experimental results for the reflection coefficient of straight resonators confirm finally the observed effect of the finite ground plane on the frequency dispersion and the scattering characteristics.  相似文献   
28.
The separation ability of branched alkane isomers (nHEX, 3MP, 22DMB) of the flexible and functionalized microporous iron(III) dicarboxylate MIL‐53(Fe)‐(CF3)2 solid is evaluated through a combination of breakthrough experiments (binary or ternary mixtures), adsorption isotherms, X‐ray diffraction temperature analysis, quasi‐elastic neutron scattering measurements and molecular dynamics simulations. A kinetically controlled molecular sieve separation between the di‐branched isomer of hexane 22DMB from a mixture of paraffins is achieved. The reported total separation between mono‐ and di‐branched alkanes which was neither predicted nor observed so far in any class of porous solids is spectacular and paves the way towards a potential unprecedented upgrading of the RON of gasoline.  相似文献   
29.
The color of polymer solar cells using an opaque electrode is given by the reflected light, which depends on the composition and thickness of each layer of the device. Metal‐oxide‐based optical spacers are intensively studied in polymer solar cells aiming to optimize the light absorption. However, the low conductivity of materials such as ZnO and TiO2 limits the thickness of such optical spacers to tenths of nanometers. A novel synthesis route of cluster‐free Al‐doped ZnO (AZO) nanocrystals (NCs) is presented for solution processing of highly conductive layers without the need of temperature annealing, including thick optical spacers on top of polymer blends. The processing of 80 nm thick optical spacers based on AZO nanocrystal solutions on top of 200 nm thick polymer blend layer is demonstrated leading to improved photocurrent density of 17% compared to solar cells using standard active layers of 90 nm in combination with thin ZnO‐based optical spacers. These AZO NCs also open new opportunities for the processing of high‐efficiency color tuned solar cells. For the first time, it is shown that applying solution‐processed thick optical spacer with polymer blends of different thicknesses can process solar cells of similar efficiency over 7% but of different colors.  相似文献   
30.
Optimum conditions for scaling up the synthesis of furyl-2 oxyrane from furfural have been determined. A continuous stirred tank reactor proved the most efficient configuration for the production of the oxirane. The kinetic model makes it possible to predict the yields of epoxide per unit volume and unit time.  相似文献   
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