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61.
I. Maggio-Aprile Ch. Renner A. Erb E. Walker Ø. Fischer 《Journal of Low Temperature Physics》1996,105(5-6):1129-1134
Scanning Tunneling Spectroscopy (STS) measurements have been carried out on the high Tc superconductor (HTS) YBa2Cu3O7– (YBCO). Using very high quality single crystals as well as hard tips, we obtained differential conductance spectra which showed various conductance features in agreement with other spectroscopic techniques. The reproducibility of our spectra allowed us to map for the first time the vortex lattice on a HTS using a STS technique1. The vortices are arranged in a short range order oblique lattice, while the cores of the flux lines show an anisotropic shape. These observations can be related to the in-plane anisotropy of YBCO. 相似文献
62.
Julián D. Arias-Londoño Author Vitae Juan I. Godino-Llorente Author Vitae Nicolás Sáenz-Lechón Author Vitae Author Vitae Germán Castellanos-Domínguez Author Vitae 《Pattern recognition》2010,43(9):3100-3112
This paper presents new a feature transformation technique applied to improve the screening accuracy for the automatic detection of pathological voices. The statistical transformation is based on Hidden Markov Models, obtaining a transformation and classification stage simultaneously and adjusting the parameters of the model with a criterion that minimizes the classification error. The original feature vectors are built up using classic short-term noise parameters and mel-frequency cepstral coefficients. With respect to conventional approaches found in the literature of automatic detection of pathological voices, the proposed feature space transformation technique demonstrates a significant improvement of the performance with no addition of new features to the original input space. In view of the results, it is expected that this technique could provide good results in other areas such as speaker verification and/or identification. 相似文献
63.
A. Prayati Author Vitae Ch. Antonopoulos Author Vitae T. Stoyanova Author Vitae C. Koulamas Author Vitae 《Journal of Systems and Software》2010,83(8):1355-1363
Substantial characteristics of wireless sensor networks, such as autonomy and miniature size, are achieved at the expense of restricted energy resources. Optimal resource management is thus among the most important challenges in WSNs development and its success requires accurate and practical models based on detailed insight concerning the factors contributing to the overall power consumption of a WSN mote. To achieve such awareness, that will enable models development, appropriate measuring test-beds and methodologies are needed, facilitating reliable and accurate power consumption measurements of critical functionalities.To cover the need for energy models that precisely define the power consumption behavior of WSN hardware platforms, this paper contributes with a measuring methodology including three steps: the design and implementation of a measuring system for a wide range of power consumption thresholds, the identification, isolation and measurement of elementary functionalities of a WSN platform with respect to their contribution to the overall mote power consumption, and the extraction of valuable conclusions based on the respective measurements resulting in the composition of a practical, yet accurate power consumption model. 相似文献
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Designing adaptive learning itineraries using features modelling and swarm intelligence 总被引:1,自引:1,他引:0
Jose Manuel Marquez Vazquez Juan Antonio Ortega Ramirez Luis Gonzalez-Abril Francisco Velasco Morente 《Neural computing & applications》2011,20(5):623-639
In this paper, Bayesian network (BN) and ant colony optimization (ACO) techniques are combined in order to find the best path through a graph representing all available itineraries to acquire a professional competence. The combination of these methods allows us to design a dynamic learning path, useful in a rapidly changing world. One of the most important advances in this work, apart from the variable amount of pheromones, is the automatic processing of the learning graph. This processing is carried out by the learning management system and helps towards understanding the learning process as a competence-oriented itinerary instead of a stand-alone course. The amount of pheromones is calculated by taking into account the results acquired in the last completed course in relation to the minimum score required and by feeding this into the learning tree in order to obtain a relative impact on the path taken by the student. A BN is used to predict the probability of success, by taking historical data and student profiles into account. Usually, these profiles are defined beforehand; however, in our approach, some characteristics of these profiles, such as the level of knowledge, are classified automatically through supervised and/or unsupervised learning. By using ACO and BN, a fitness function, responsible for automatically selecting the next course in the learning graph, is defined. This is done by generating a path which maximizes the probability of each user??s success on the course. Therefore, the path can change in order to adapt itself to learners?? preferences and needs, by taking into account the pedagogical weight of each learning unit and the social behaviour of the system. 相似文献
66.
Generalized honeycomb torus (GHT) is recognized as an attractive alternative to existing torus interconnection networks in parallel computing systems. Assume that m and d are integers with m ? 2 and d ? 8. This paper addresses the fault-tolerant hamiltonicity of GHT(m, 2d, d) with fault set F = {(w, y), (x, y)}, where w < x, w + y is even and x + y is odd. We show that such a faulty GHT is hamiltonian by presenting a systematic method for constructing a fault-free hamiltonian cycle. This result reveals another appealing feature of GHTs. 相似文献
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时间序列分析是动态数据分析的重要方法,在多学科领域中得到广泛的研究和运用.研究时间序列分析在城市轨道交通自动售检票系统数据分析中的应用方法,并结合某线路AFC系统的历史沉淀数据,给出两个完整的时间序列分析案例,其分析方法能够为AFC运营管理提供有效决策的手段. 相似文献