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91.
The crystallization of calcium carbonate was investigated on pristine and non-covalently modified carbon nanotubes (CNTs) using the vapor diffusion technique in a calcium chloride solution. Non-covalent modification was accomplished by treating the carbon nanostructures with the amphiphilic copolymer poly(isoprene-b-acrylic acid). Calcium carbonate crystals grown on the surface and in the interstitial channels of CNT buckypapers were observed in both cases. Scanning electron microscopy analysis of the untreated CNTs showed the characteristic rhombohedral morphology of calcite crystals, while in the case of modified material spherical and ellipsoidal crystals, consisted of nanocrystallites, were observed. X-ray diffraction analysis showed the presence of calcite crystals in both cases. 相似文献
92.
A new feature extraction process is proposed for gait representation and recognition. The new system is based on the Radon transform of binary silhouettes. For each gait sequence, the transformed silhouettes are used for the computation of a template. The set of all templates is subsequently subjected to linear discriminant analysis and subspace projection. In this manner, each gait sequence is described using a low-dimensional feature vector consisting of selected Radon template coefficients. Given a test feature vector, gait recognition and verification is achieved by appropriately comparing it to feature vectors in a reference gait database. By using the new system on the Gait Challenge database, very considerable improvements in recognition performance are seen in comparison to state-of-the-art methods for gait recognition. 相似文献
93.
Motion segmentation refers to the problem of separating the objects in a video sequence according to their motion. It is a fundamental problem of computer vision, since various systems focusing on the analysis of dynamic scenes include motion segmentation algorithms. In this paper we present a novel approach, where a video shot is temporally divided in successive and overlapping windows and motion segmentation is performed on each window respectively. This attribute renders the algorithm suitable even for long video sequences. In the last stage of the algorithm the segmentation results for every window are aggregated into a final segmentation. The presented algorithm can handle effectively asynchronous trajectories on each window even when they have no temporal intersection. The evaluation of the proposed algorithm on the Berkeley motion segmentation benchmark demonstrates its scalability and accuracy compared to the state of the art. 相似文献
94.
In this paper we present the Gaia2JADE process concerning how one can implement a multi-agent system with the JADE framework using the Gaia methodology for analysis and design purposes. This process is particularly dedicated to the conversion of Gaia models to JADE code. It is described using the Software Process Engineering Metamodel (SPEM) and extends the one proposed by FIPA for describing the Gaia modeling process. Thus, it proposes to potential MAS developers a process that covers the full software development lifecycle. This work is based on the experience we have acquired by applying this process for implementing a real-word multi-agent system conceived for providing e-services to mobile users. With this paper, we share this experience with future multi-agent systems (MAS) developers, who would like to follow this process, taking into account several technical issues that emerged during the implementation phase, helping them to easily model and implement their systems. 相似文献
95.
Bryan Godbolt Nikolaos I. Vitzilaios Alan F. Lynch 《Journal of Intelligent and Robotic Systems》2013,70(1-4):385-399
Autonomous helicopter flight provides a challenging control problem. In order to evaluate control designs, an experimental platform must be developed in order to conduct flight tests. However, the literature describing existing platforms focuses on the hardware details, while little information is given regarding software design and control algorithm implementation. This paper presents the design, implementation, and validation of an experimental helicopter platform with a primary focus on a software framework optimized for controller development. In order to validate the operation of this platform and provide a basis for comparison with more sophisticated nonlinear designs, a PID controller with feedforward gravity compensation is derived using the generally accepted small helicopter model and tested experimentally. 相似文献
96.
Nikolaos Thomos Nikolaos V Boulgouris Michael G Strintzis 《IEEE transactions on image processing》2005,14(11):1890-1901
A novel image transmission scheme is proposed for the communication of set partitioning in hierarchical trees image streams over wireless channels. The proposed scheme employs turbo codes and Reed-Solomon codes in order to deal effectively with burst errors. An algorithm for the optimal unequal error protection of the compressed bitstream is also proposed and applied in conjunction with an inherently more efficient technique for product code decoding. The resulting scheme is tested for the transmission of images over wireless channels. Experimental evaluation clearly demonstrates the superiority of the proposed transmission system in comparison to well-known robust coding schemes. 相似文献
97.
Jeffery Karafa Mihalis M. Golias Stephanie Ivey Georgios K. D. Saharidis Nikolaos Leonardos 《The International Journal of Advanced Manufacturing Technology》2013,65(1-4):473-484
In this paper, the berth allocation problem with stochastic vessel handling times is formulated as a bi-objective problem. To solve the resulting problem, an evolutionary algorithm-based heuristic and a simulation-based Pareto front pruning algorithm is proposed. Computational examples show that the proposed approach provides solutions superior to the ones where the expected value of the vessel handling times is used. 相似文献
98.
Multi-Camera Human Activity Monitoring 总被引:1,自引:0,他引:1
Loren Fiore Duc Fehr Robot Bodor Andrew Drenner Guruprasad Somasundaram Nikolaos Papanikolopoulos 《Journal of Intelligent and Robotic Systems》2008,52(1):5-43
With the proliferation of security cameras, the approach taken to monitoring and placement of these cameras is critical. This
paper presents original work in the area of multiple camera human activity monitoring. First, a system is presented that tracks
pedestrians across a scene of interest and recognizes a set of human activities. Next, a framework is developed for the placement
of multiple cameras to observe a scene. This framework was originally used in a limited X, Y, pan formulation but is extended to include height (Z) and tilt. Finally, an active dual-camera system for task recognition at multiple resolutions is developed and tested. All
of these systems are tested under real-world conditions, and are shown to produce usable results.
This work has been supported by the NSF through grants #IIS-0219863, #CNS-0224363, #CNS-0324864, #IIP-0443945, #CNS-0420836,
#IIP-0726109, and #CNS-0708344. 相似文献
99.
Nikolaos Dimitratos Jose Antonio Lopez-Sanchez Graham J. Hutchings 《Topics in Catalysis》2009,52(3):258-268
The use of renewable feedstocks, derived from biomass, for the chemical industry is discussed. The modern chemical industry
is based around platform chemicals, e.g. ethene, propene, benzene and xylenes, which are readily derived from oil, and using
these intermediates a broad range of finished products can be derived. While it is feasible that biomass can be converted
to syngas and hence to existing key platform chemicals, this loses all of the chemical complexity that is inherent in bio-derived
molecules. In this paper some of the options are considered and, in particular, the oxidation of glucose and glycerol using
gold nanoparticles supported on carbon is described. We also contrast the oxidation of glycerol using supported gold and gold–palladium
alloys prepared using an impregnation technique, since the gold–palladium alloys have been shown to be highly effective for
the oxidation of alcohols and the synthesis of hydrogen peroxide. 相似文献
100.
Vaios T. Karathanos Ioannis Mourtzinos Konstantina Yannakopoulou Nikolaos K. Andrikopoulos 《Food chemistry》2007,101(2):652-658
In the present study, complexes of vanillin with β-cyclodextrin (β-CD) were prepared by the freeze-drying method. The formation of the inclusion complex was confirmed by differential scanning calorimetry (DSC). DSC thermograms indicated that the endothermic peak of vanillin and the physical mixture of vanillin with β-CD, due to the melting of vanillin crystals, were absent in DSC thermograms obtained for the freeze-dried inclusion complex. Moreover, the DSC studies under oxidation conditions indicate that the complex of vanillin with β-CD is protected towards oxidation since it remains intact at temperatures where the free vanillin is oxidising. The structure of the complex in aqueous solutions was established by nuclear magnetic resonance (NMR) studies and specifically by two-dimensional rotational frame NOE spectra. NMR studies showed inclusion of the entire vanillin molecule in the β-CD in a tilted manner and with the aldehyde group in the primary side. The stoichiometry of the complex was 1:1. A phase solubility study was performed by mixing an excess amount of vanillin with aqueous solutions containing increasing amounts of β-CD. The results indicated that the complex of a vanillin/β-CD inclusion is more soluble in water than vanillin alone. 相似文献