Efficient analysis and experimental verification of substrate‐integrated slab waveguides for wideband microwave applications

This article presents a substrate integrated waveguide, named the substrate‐integrated slab waveguide (SISW), which exhibits a wide operation bandwidth. It consists of an integrated rectangular waveguide filled with a periodically perforated dielectric medium. An efficient procedure has been developed for the calculation of the dispersion diagram of SISWs, based on the Floquet theorem, in conjunction with the segmentation technique and the boundary‐integral–resonant‐mode‐expansion (BI‐RME) method. Numerical and experimental results confirm the performance of these waveguides and the efficiency of the analysis method. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

Virtual agent multimodal mimicry of humans

This work is about multimodal and expressive synthesis on virtual agents, based on the analysis of actions performed by human users. As input we consider the image sequence of the recorded human behavior. Computer vision and image processing techniques are incorporated in order to detect cues needed for expressivity features extraction. The multimodality of the approach lies in the fact that both facial and gestural aspects of the user’s behavior are analyzed and processed. The mimicry consists of perception, interpretation, planning and animation of the expressions shown by the human, resulting not in an exact duplicate rather than an expressive model of the user’s original behavior.     

冷却剂丧失条件下钠冷快堆棒束传热的三维蒙特卡罗模拟方法

采用蒙特卡罗方法分析钠冷快堆在假想冷却剂丧失条件下燃料棒束的钠两相流传热问题。以分子运动理论的基本定律为基础，开发出替代宏观经验模型来分析反应堆棒束中的钠蒸发率和冷凝率的微观模型，且采用三维蒙特卡罗方法模拟分子的运动轨迹，分子间的碰撞率以及分子与棒束、分子与棒束组件盒壁的碰撞率。对包壳干涸区的再浸润现象用动力膜模型描述，并计算了通过液膜的液体速度分布和平均液膜速度，对于从冷凝液膜蒸发的钠分子则被重新记为蒙特卡罗计算的源项。用微观和宏观模型相结合的方法数字模拟了德国卡斯鲁尔研究中心的堆外钠沸腾实验。     

Analytical framework for end-to-end design of optical burst-switched networks

This paper presents an analytical model of TCP throughput in optical burst-switched (OBS) networks. Several parameters characterize this system and influence the network design process, such as the assembly time, the access bandwidth, the burst loss rate, and they are taken into account in the formulation of TCP send rates. Moreover burst loss is considered a consequence of contention in core nodes and it is formulated in relation to a quite general core node architecture. The novelty of the work is represented by the possibility of analytically representing the whole end-to-end connection so that a fast and effective tool to evaluate the relationships between network and access design is provided. An application example is given to prove the practical significance of the approach. Simulation results are provided to validate the model and the related assumptions.     

Modified friction factor correlation for CICC’s based on a porous media analogy

The first cool-down of the EDIPO (European DIPOle) test facility is foreseen to take place in 2011 by means of the existing 1.2 kW cryoplant at EPFL-CRPP Villigen. In this work, the thermo-hydraulic analysis of the EDIPO cool-down is performed in order both to assess the its duration and to optimize the procedure. The cool-down is driven by the helium flowing in both the outer cooling channel and in the windings connected hydraulically in parallel. We take into account limitations due to the pressure drop in the cooling circuit and the refrigerator capacity as well as heat conduction in the iron yoke. Two schemes of the hydraulic cooling circuit in the EDIPO windings are studied (coils connected in series and coils connected in parallel). The analysis is performed by means of an analytical model complemented by and numerical model. The results indicate that the cool-down to 5 K can be achieved in about 12 days.     

Pre-emptive versus non-pre-emptive real time scheduling in intelligent mobile robotics

Autonomous and semi-autonomous mobile robots have to perform a multiplicity of concurrent activities in order to carry out useful tasks in unstructured human-populated environments. Even if it is commonly accepted that a successful accomplishment of assigned tasks requires some sort of real time capability to quickly react and adapt to environmental changes, it is not clear which operating system support is best suited for the scheduling and synchronizing of concurrent activities with different timing requirements. This paper discusses this problem, comparing two different real time scheduling policies for autonomous robot applications: pre-emptive rate monotonic and non pre-emptive Earliest Deadline First (EDF). Experimental results are presented and evaluated.     

Definition of a practical multi-criteria procedure for selecting the best coagulant in a chemically assisted primary sedimentation process for the treatment of urban wastewater

Chemically assisted primary sedimentation (CAPS) or chemically enhanced primary treatment (CEPT) consists of adding chemicals in order to increase the coagulation, flocculation and sedimentation of raw wastewater. Over the last twenty years, the use of CAPS has increased due to the development of better coagulants and flocculation enhancers, stricter standards as well as the need for low-energy treatment technologies, especially in developing countries. This paper defines a very simple multi-criteria procedure to be used in order to select the best combination of coagulant and dose when using jar tests. It is based on the adoption of the following 5 criteria: COD percentage removal, sludge volume after 2 h, coagulant dose, coagulant cost, pH percentage variation. The mathematical affordability of the procedure was tested by comparing it with the well known analytic hierarchy process.     

19-Azasqualene-2,3-epoxide and its N-oxide: Metabolic fate and inhibitory effect on sterol biosynthesis in Saccharomyces cerevisiae

19-Azasqualene-2,3-epoxide was more inhibitory than the corresponding N-oxide against 2,3-oxidosqualene cyclase (OSC) solubilized from Saccharomyces cerevisiae (IC₅₀ 7±2 and 25±5 μM, respectively). Both compounds showed a reversible, noncompetitive-type inhibition on solubilized OSC. Different inhibitory properties between the compounds were especially evident when measuring [¹⁴C]acetate incorporation into nonsaponifiable lipids extracted from treated cells. In cells treated with 19-azasqualene-2,3-epoxide at 30 μM, the radioactivity associated with the oxidosqualene fraction, which was negligible in the controls, rose to over 40% of the nonsaponifiable lipids, whereas it remained at a slightly appreciable level in cells treated with the N-oxide derivative under the same conditions. 19-Azasqualene-2,3-epoxide was also more effective than the N-oxide as a cell growth inhibitor (minimal concentration of compound needed to inhibit yeast growth: 45 and >100 μM, respectively). The two inhibitors underwent different metabolic fates in the yeast: while 19-azasqualene-2,3-epoxide did not undergo any transformation, its N-oxide was actively reduced to the corresponding amine in whole and in “ultrasonically stimulated” cells. The N-oxide reductases responsible for this transformation appear to be largely confined within the microsomal fractions and require NADPH for their activity. A possible relationship between the inhibitory properties of the two compounds and their metabolic fates is discussed.     

Presentation‐Oriented Key‐Frames Coding Based on Fractals

This paper focuses on the problem of key‐frames coding and proposes a new promising approach based on the use of fractals. The summary, made of a set of key‐frames selected from a full‐length video sequence, is coded by using a 3D fractal scheme. This allows the video presentation tool to expand the video sequence in a “natural” way by using the property of the fractals to reproduce the signal at several resolutions. This feature represents an important novelty of this work with respect to the alternative approaches, which mainly focus on the compression ratio without taking into account the presentation aspect of the video summary. In devising the coding scheme, we have taken care of the computational complexity inherent in fractal coding. Accordingly, the key‐frames are first wavelet transformed, and the fractal coding is then applied to each subband to reduce the search range. Experimental results show the effectiveness of the proposed approach.