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1.
2.
Glass laminates have been readily obtained by photocuring at ambient temperature of an acrylic adhesive consisting either of a liquid resin or a solid thermoplastic polymer. The light-induced polymerization process was followed by real-time infrared spectroscopy. Close to 100% conversion was reached within a few seconds of exposure, by taking as the photoinitiator an α-hydroxy alkylphenone or an aryl phosphine oxide. A liquid formulation containing an aliphatic polyurethane–acrylate oligomer, acrylic acid, and butyl acrylate gives the best performance in terms of reactivity, adhesion, impact resistance, and transparency. The impact resistance was further increased by introducing a polycarbonate core between the two glass plates. The solid thermoplastic polymer was obtained either by casting from a solution containing an aliphatic polyurethane, an acrylate oligomer, and the photoinitiator or by mixing these compounds in the molten state and further extrusion. The glass assembly was heated above the softening temperature (80°C) under a 1 MPa pressure and cured by a 1 min exposure to UV radiation to give a strongly adhesive laminate showing good transparency and long term weatherability. © 1995 John Wiley & Sons, Inc. 相似文献
3.
We present the first step of a research aimed at automating a driven interactive 3D modeling of an existing architectural object. The method is based on oriented multi-image spherical panoramas produced by stitching techniques. The photogrammetric process has two steps: the creation of a semi-automatic process to find homolog points in two panoramas; the creation of parametric definitions for an interactive modeling creating points, segments, and surfaces based on the plotted points in the first step. By connecting these two steps, the creation of the model will be automatic, as we indicate the necessary points in just one panoramic photo. The principals of multi-view geometry and epipolar geometry were applied to simplify the calculation in the first step in order to create an automatic identification of the correspondent points in the other panorama. The epipolar geometry is described by both analytical and graphical programming, implementing in the first case a C++ application and in the second case a Rhinoceros and Grasshopper application. A case study of the Ponte Rotto in Rome (Italy) is presented. 相似文献
4.
This work aims at demonstrating the interest of a new methodology for the design and optimization of composite materials and structures. Coupling reliability methods and homogenization techniques allow the consideration of probabilistic design variables at different scales. The main advantage of such an original micromechanics-based approach is to extend the scope of solutions for engineering composite materials to reach or to respect a given reliability level. This approach is illustrated on a civil engineering case including reinforced fiber composites. Modifications of microstructural components properties, manufacturing process, and geometry are investigated to provide new alternatives for design and guidelines for quality control. 相似文献
5.
Moussa Yahia Pascal Acco Malek Benslama 《International Journal of Control, Automation and Systems》2011,9(6):1021-1027
This paper proposes to decompose the nonlinear dynamic of a chaotic system with Chebyshev polynomials to improve performances
of its estimator. More widely than synchronization of chaotic systems, this algorithm is compared to other nonlinear stochastic
estimator such as Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF). Chebyshev polynomials orthogonality properties
is used to fit a polynomial to a nonlinear function. This polynomial is then used in an Exact Polynomial Kalman Filter (ExPKF)
to run real time state estimation. The ExPKF offers mean square error optimality because it can estimate exact statistics
of transformed variables through the polynomial function. Analytical expressions of those statistics are derived so as to
lower ExPKF algorithm computation complexity and allow real time applications. Simulations under the Additive White Gaussian
Noise (AWGN) hypothesis, show relevant performances of this algorithm compared to classical nonlinear estimators. 相似文献
6.
Hachem Moussa Tong Gao I-Ling Yen Farokh Bastani Jun-Jang Jeng 《Service Oriented Computing and Applications》2010,4(1):17-31
Many application domains are increasingly leveraging service-oriented architecture (SOA) techniques to facilitate rapid system
deployment. Many of these applications are time-critical and, hence, real-time assurance is an essential step in the service
composition process. However, there are gaps in existing service composition techniques for real-time systems. First, admission
control is an essential technique to assure the time bound for service execution, but most of the service composition techniques
for real-time systems do not take admission control into account. A service may be selected for a workflow during the composition
phase, but then during the grounding phase, the concrete service may not be able to admit the workload. Thus, the entire composition
process may have to be repeated. Second, communication time is an important factor in real-time SOA, but most of the existing
works do not consider how to obtain the communication latencies between services during the composition phase. It is clear
that maintaining a full table of communication latencies for all pairs of services is infeasible. Obtaining communication
latencies between candidate services during the composition phase can also be costly, since many candidate services may not
be used for grounding. Thus, some mechanism is needed for estimating the communication latency for composite services. In
this paper, we propose a three-phase composition approach to address the above issues. In this approach, we first use a highly
efficient but moderately accurate algorithm to eliminate most of the candidate compositions based on estimated communication
latencies and assured service response latency. Then, a more accurate timing prediction is performed on a small number of
selected compositions in the second phase based on confirmed admission and actual communication latency. In the third phase,
specific concrete services are selected for grounding, and admissions are actually performed. The approach is scalable and
can effectively achieve service composition for satisfying real-time requirements. Experimental studies show that the three-phase
approach does improve the effectiveness and time for service composition in SOA real-time systems. In order to support the
new composition approach, it is necessary to effectively specify the needed information. In this paper, we also present the
specification model for timing-related information and the extension of OWL-S to support this specification model. 相似文献
7.
In this paper we propose a compact split step Padé scheme (CSSPS) to solve the scalar higher-order nonlinear Schrödinger equation (HNLS) with higher-order linear and nonlinear effects such as the third and fourth order dispersion effects, Kerr dispersion, stimulated Raman scattering and power law nonlinearity. The stability of this method has been proved. It has been shown as well that the CSSPS method gives the same results as classical numerical methods like the split step Fourier method and Crank–Nicholson (CN) method but it presents many advantages over theme. It is more efficient. This proposed scheme is well suited to higher-order dispersion effects and readily generalized for nonlinear and dispersion managed fibers. We tested this scheme for the case of the quintic nonlinearity and confirmed that this effect has no significant role on the propagation of single solitons. 相似文献
8.
Moussa Sofiane Karoui Yannick Deville Shahram Hosseini Abdelaziz Ouamri 《Pattern recognition》2012,45(12):4263-4278
Remote sensing has become an unavoidable tool for better managing our environment, generally by realizing maps of land cover using classification techniques. Traditional classification techniques assign only one class (e.g., water, soil, grass) to each pixel of remote sensing images. However, the area covered by one pixel contains more than one surface component and results in the mixture of these surface components. In such situations, classical classification is not acceptable for many major applications, such as environmental monitoring, agriculture, mineral exploration and mining, etc. Most methods proposed for treating this problem have been developed for hyperspectral images. On the contrary, there are very few automatic techniques suited to multispectral images. In this paper, we propose new unsupervised spatial methods (called 2D-Corr-NLS and 2D-Corr-NMF) in order to unmix each pixel of a multispectral image for better recognizing the surface components constituting the observed scene. These methods are related to the blind source separation (BSS) problem, and are based on sparse component analysis (SCA), clustering and non-negativity constraints. Our approach consists in first identifying the mixing matrix involved in this BSS problem, by using the first stage of a spatial correlation-based SCA method with very limited source sparsity constraints, combined with clustering. Non-negative least squares (NLS) or non-negative matrix factorization (NMF) methods are then used to extract spatial sources. An important advantage of our proposed methods is their applicability to the possibly globally underdetermined, but locally (over)determined BSS model in multispectral remote sensing images. Experiments based on realistic synthetic mixtures and real multispectral images collected by the Landsat ETM+ and the Formosat-2 sensors are performed to evaluate the performance of the proposed approach. We also show that our methods significantly outperform the sequential maximum angle convex cone (SMACC) method. 相似文献
9.
Context
Formal methods are very useful in the software industry and are becoming of paramount importance in practical engineering techniques. They involve the design and modeling of various system aspects expressed usually through different paradigms. These different formalisms make the verification of global developed systems more difficult.Objective
In this paper, we propose to combine two modeling formalisms, in order to express both functional and security timed requirements of a system to obtain all the requirements expressed in a unique formalism.Method
First, the system behavior is specified according to its functional requirements using Timed Extended Finite State Machine (TEFSM) formalism. Second, this model is augmented by applying a set of dedicated algorithms to integrate timed security requirements specified in Nomad language. This language is adapted to express security properties such as permissions, prohibitions and obligations with time considerations.Results
The proposed algorithms produce a global TEFSM specification of the system that includes both its functional and security timed requirements.Conclusion
It is concluded that it is possible to merge several requirement aspects described with different formalisms into a global specification that can be used for several purposes such as code generation, specification correctness proof, model checking or automatic test generation. In this paper, we applied our approach to a France Telecom Travel service to demonstrate its scalability and feasibility. 相似文献10.
A new concept of a buffer layer in superconducting thick film technology was tested. The idea is based on increasing the NdBa2Cu3Ox melt viscosity at the processing temperature near the substrate by using higher ratios of Nd4Ba2Cu2Oz solid phase in the first screen printed pass which is considered as a buffer layer. Different compositions, thicknesses and
thermal schedules were used to optimise the buffer layer. The optimised buffer layer was employed in the fabrication of NdBa2Cu3Oy thick films on yttria stabilized zirconia (YSZ) substrates using the top seeding melt growth (TSMG) technique. Using the
buffer layer was effective in preventing a large amount of liquid (BaCuO2-CuO) from severe interaction with the substrate during the prolonged time in the TSMG technique. Consequently, a large superconducting
single domain was obtained. Thick films were melt processed in 0.1% O2 in Ar atmosphere to suppress the Nd1 + xBa2 − xCu3Oy (Nd123SS) solid solution formation. The produced thick films have high transition temperature (TC) and improved microstructures. 相似文献