The PANOPTIC Camera: A Plenoptic Sensor with Real-Time Omnidirectional Capability

A new biologically-inspired vision sensor made of one hundred “eyes” is presented, which is suitable for real-time acquisition and processing of 3-D image sequences. This device, named the Panoptic camera, consists of a layered arrangement of approximately 100 classical CMOS imagers, distributed over a hemisphere of 13 cm in diameter. The Panoptic camera is a polydioptric system where all imagers have their own vision of the world, each with a distinct focal point, which is a specific feature of the Panoptic system. This enables 3-D information recording such as omnidirectional stereoscopy or depth estimation, applying specific signal processing. The algorithms dictating the image reconstruction of an omnidirectional observer located at any point inside the hemisphere are presented. A hardware architecture which has the capability of handling these algorithms, and the flexibility to support additional image processing in real time, has been developed as a two-layer system based on FPGAs. The detail of the hardware architecture, its internal blocks, the mapping of the algorithms onto the latter elements, and the device calibration procedure are presented, along with imaging results.     

Use of signal processing imaging for the study of a 3D package in harsh environment

Assembly technologies follow the reduction in size of circuit board components and correlatively the number of active layers increases significantly. Therefore, during a conventional acoustic analysis, the obtained image becomes more and more complicated to analyze. In a previous paper, we focused our research on a method for a suitable visualization of the timescale of an acoustic signal (CWT). In this paper we present the use of the non-destructive control for the study of a 3D package submitted to accelerated ageing tests using harsh conditions.     

Nido-Hydroborate-Based Electrolytes for All-Solid-State Lithium Batteries

Hydroborate-based solid electrolytes have recently been successfully employed in high voltage, room temperature all-solid-state sodium batteries. The transfer to analogous lithium systems has failed up to now due to the lower conductivity of the corresponding lithium compounds and their high cost. Here LiB₁₁H₁₄ nido-hydroborate as a cost-effective building block and its high-purity synthesis is introduced. The crystal structures of anhydrous LiB₁₁H₁₄ as well as of LiB₁₁H₁₄-based mixed-anion solid electrolytes are solved and high ionic conductivities of 1.1 × 10⁻⁴ S cm⁻¹ for Li₂(B₁₁H₁₄)(CB₁₁H₁₂) and 1.1 × 10⁻³ S cm⁻¹ for Li₃(B₁₁H₁₄)(CB₉H₁₀)₂ are obtained, respectively. LiB₁₁H₁₄ exhibits an oxidative stability limit of 2.6 V versus Li⁺/Li and the proposed decomposition products are discussed based on density functional theory calculations. Strategies are discussed to improve the stability of these compounds by modifying the chemical structure of the nido-hydroborate cage. Galvanostatic cycling in symmetric cells with two lithium metal electrodes shows a small overpotential increase from 22.5 to 30 mV after 620 h (up to 0.5 mAh cm⁻²), demonstrating that the electrolyte is compatible with metallic anodes. Finally, the Li₂(B₁₁H₁₄)(CB₁₁H₁₂)  electrolyte is employed in a proof-of-concept half cell with a TiS₂ cathode with a capacity retention of 82% after 150 cycles at C/5.     

Smart gateways switching control algorithms based on tropospheric propagation forecasts

The use Q/V band spectrum for the feeder links of high throughput satellites and the need to cope with the significant propagation impairments at those frequencies motivate the development of smart diversity techniques. Those techniques aim at improving the availability level of the overall feeder link with a limited level of redundancy. The combinatorial gain of availability provided by those techniques can be obtained only if efficient switching methodologies are developed, performing the best trade‐off between system flexibility and channel prediction accuracy. This paper proposes various propagation forecast mechanisms for the control of switching between gateways in smart diversity, corresponding to various system assumptions in terms of required anticipation time for the triggering of the switches. The performances of those algorithms are then assessed against measured attenuation and meteorological data. It enables to evaluate the performance degradation regarding an idealized case.     

Improving mobile ad hoc network routing with satellite out‐of‐band signaling

Routing in mobile ad hoc networks is a complex task due to the mobility of the nodes and the constraints linked to a wireless multihop network (e.g., limited bandwidth, collisions, and bit errors). These adverse conditions impair not only data traffic but also routing signaling traffic, which feeds route computation. In this contribution, we propose to use satellite communications to help in the distribution of mobile ad hoc network routing signaling. The optimized link‐state routing (OLSR) is chosen among several routing protocols to be extended with satellite‐based signaling, yielding a version we call OLSR hybrid signaling (OLSR‐H). This new scheme is evaluated through simulations and yields improvements of approximately 10% in the data delivery ratio compared with a regular OLSR. This evaluation is conducted using two different network topology models, one being fit for representing forest firefighting operations. Copyright © 2013 John Wiley & Sons, Ltd.     

Microstructured air-silica fibres: Recent developments in modelling, manufacturing and experiment

The main modelling methods devoted to microstructured air-silica optical fibres (MOFS) are presented and discussed. Then, the specific propagation properties ofMOFS are studied in detail. Characteristics measured on fibres manufactured in our laboratory or reported in the literature are analysed. A large number of potential and demonstrated applications are presented and the obtained performances are discussed. A particular attention is given to hollow-core photonic bandgap fibres and their applications.     

如何实现真实世界下的PC“绿色”能效

计算机原设备制造商（OEM）正面对商业、环保和法规等多方面的压力,需要体现他们产品的能效,提供更“绿色”的台式个人电脑（PC）和服务器。这使设计这些产品的工程师需要设计出符合诸如美国80 PLUS、“能源之星”（ENERGYSTAR）和计算产业拯救气候行动计划（CSCI）等能效标准的PC电源。     

Environmental selenium research: from microscopic processes to global understanding

Selenium is a natural trace element that is of fundamental importance to human health. The extreme geographical variation in selenium concentrations in soils and food crops has resulted in significant health problems related to deficient or excess levels of selenium in the environment. To deal with these kinds of problems in the future it is essential to get a better understanding of the processes that control the global distribution of selenium. The recent development of analytical techniques and methods enables accurate selenium measurements of environmental concentrations, which will lead to a better understanding of biogeochemical processes. This improved understanding may enable us to predict the distribution of selenium in areas where this is currently unknown. These predictions are essential to prevent future Se health hazards in a world that is increasingly affected by human activities.     

Modelling mechanical properties of spruce and Douglas fir timber by means of X-ray and grain angle measurements for strength grading purpose

This study proposes a model using data from a scanner (X-ray and grain angle measurements) to perform strength grading. The research also includes global measurements of modulus of elasticity (obtained by vibrations and ultrasound methods), static bending stiffness and bending strength of 805 boards of Douglas fir and 437 boards of spruce. This model can be used in an industrial context since it requires low computational time. The results of this study show that the developed model gives better results than the global non-destructive measurements of the elastic modulus commonly used in the industry. It also shows that this improvement is particularly higher in the case of Douglas fir than for spruce. The comparison has been made on both the quality of the mechanical properties assessment and on the improvement of the grading process according to the European standards by using different index.