小波分析作为现代数学理论与应用科学完美结合的典范在世界各国科学技术界掀起了一场轩然大波。本文简要介绍新加坡国立大学(National University of Singapore)在政府“小波战略研究计划”(Wavelets Strategic Research Ptogramme)资助...小波分析作为现代数学理论与应用科学完美结合的典范在世界各国科学技术界掀起了一场轩然大波。本文简要介绍新加坡国立大学(National University of Singapore)在政府“小波战略研究计划”(Wavelets Strategic Research Ptogramme)资助下,在该领域所取得的理论及应用研究成果。新加坡国立大学的小波研究起步于八十年代后期。在随后几年里,该校研究工作者在小波数学理论方面取得了一系列具有国际影响的研究成果。为了进一步推动这项研究并将其成果应用于工业实践,新加坡政府于1996年拨款329万新元(约合人民币1800万元)资助成立小波战略研究小组(简称WSRP),其成员包括来自该大学及国家实验宝的十多名数学家,应用科学家及工程师。小组成立以来,在小波理论及应用研究领域取得了更大的进展。平均每年完成科技论文近30篇,其中绝大多数发表在国际著名的数学与工程刊物上。与此同时,其应用研究也已引起工业界的重视。WSRP与中、美、英、日等国著名小波研究机构及学者建立了密切联系以期共同促进这一理论的发展与应用。1990年,新加坡国立大学的小波研究工作者率先在国际上提出了向量小波(multiwavelet)理论。这一理论及其应用现在已成为国际上小波研究的一个重要领域。近年来,WSRP进一步提出了新的向量小波构造?展开更多
Hydrodynamic and turbulent structures in the trayed bubble column with 1.2 m inner diameter have been characterized from liquid-phase velocity-time series data obtained by the hot-film anemometer. Wavelet transform an...Hydrodynamic and turbulent structures in the trayed bubble column with 1.2 m inner diameter have been characterized from liquid-phase velocity-time series data obtained by the hot-film anemometer. Wavelet transform analysis was used for denoising the measured data and also for evaluating quantifiers of turbulence, viz., local intermittency measure, intermittency index and flatness factor. These quantifiers help in detecting the passage of bubbles and reveal the hidden structures and patterns in data. Also, the wavelet scalewise analysis of the turbulence at various locations in the column and under different operating conditions could be used to build a direct relationship between the local gas holdup and flatness factor. The methodology is therefore suitable for online evaluation of the trayed bubble column performance and shows promise for developing strategies for improving process performance.展开更多
Objective: To study extracellular multi-neuron activity in the nervous system based on wavelet-fractal technique. Methods: The wavelet transform was employed to decompose the original signal and obtain 4 sub-patterns....Objective: To study extracellular multi-neuron activity in the nervous system based on wavelet-fractal technique. Methods: The wavelet transform was employed to decompose the original signal and obtain 4 sub-patterns. The dividing fractal dimensions of these sub-patterns were computed. A knn-classier was used to classify feature vectors. Results: Not all the elements in feature vector DimDC were very powerful for this pattern recognition problem through the empirical study of noise signals. The most effective feature vector was defined as DimDC= (d3:d4) above. Conclusion:Wavelet fractal algorithm has high accuracy and provides a powerful tool for clinical application.展开更多
The aim of the study was to determine the harmfulness of leaf miners and their species composition on winter wheat for the improvement of methods to control them. In order to determine the dates of the treatments, it ...The aim of the study was to determine the harmfulness of leaf miners and their species composition on winter wheat for the improvement of methods to control them. In order to determine the dates of the treatments, it was necessary to catch adult flies. The researchers used yellow 25 x 40 cm sticky traps placed on three control plots to catch the adults. Monitoring of cereal leaf miners flights in winter wheat was carried out in Babor6wko （greater Poland voivodeship）. Yellow traps were placed above the tops of wheat during vegetation period. The number of damaged wheat stems was recorded. Fluctuations in weather conditions during the research affected the dynamics of leaf miner flies considerably. The maximum flights of leaf miner flies on winter wheat crops in years of the studies took place in May. The dynamics of leaf miners flights were different in growing season 2008 and 2009. The most common species were： Chromatomyia nigra （Ztt.）, Chromatomyia fuscula （Ztt.） and Poemyza superciliosa （Ztt.）. It was also discovered that the species composition of Agromyzidae damaging the winter wheat, changes in particular years. The results differ from the results of the previous research, which the dominant species were Phytomyza nigra （Mg.） and Agromyza ambiqua （FII.）.展开更多
文摘小波分析作为现代数学理论与应用科学完美结合的典范在世界各国科学技术界掀起了一场轩然大波。本文简要介绍新加坡国立大学(National University of Singapore)在政府“小波战略研究计划”(Wavelets Strategic Research Ptogramme)资助下,在该领域所取得的理论及应用研究成果。新加坡国立大学的小波研究起步于八十年代后期。在随后几年里,该校研究工作者在小波数学理论方面取得了一系列具有国际影响的研究成果。为了进一步推动这项研究并将其成果应用于工业实践,新加坡政府于1996年拨款329万新元(约合人民币1800万元)资助成立小波战略研究小组(简称WSRP),其成员包括来自该大学及国家实验宝的十多名数学家,应用科学家及工程师。小组成立以来,在小波理论及应用研究领域取得了更大的进展。平均每年完成科技论文近30篇,其中绝大多数发表在国际著名的数学与工程刊物上。与此同时,其应用研究也已引起工业界的重视。WSRP与中、美、英、日等国著名小波研究机构及学者建立了密切联系以期共同促进这一理论的发展与应用。1990年,新加坡国立大学的小波研究工作者率先在国际上提出了向量小波(multiwavelet)理论。这一理论及其应用现在已成为国际上小波研究的一个重要领域。近年来,WSRP进一步提出了新的向量小波构造?
文摘Hydrodynamic and turbulent structures in the trayed bubble column with 1.2 m inner diameter have been characterized from liquid-phase velocity-time series data obtained by the hot-film anemometer. Wavelet transform analysis was used for denoising the measured data and also for evaluating quantifiers of turbulence, viz., local intermittency measure, intermittency index and flatness factor. These quantifiers help in detecting the passage of bubbles and reveal the hidden structures and patterns in data. Also, the wavelet scalewise analysis of the turbulence at various locations in the column and under different operating conditions could be used to build a direct relationship between the local gas holdup and flatness factor. The methodology is therefore suitable for online evaluation of the trayed bubble column performance and shows promise for developing strategies for improving process performance.
基金Supported by the National Natural Science Foundation of China (No. 60371034)
文摘Objective: To study extracellular multi-neuron activity in the nervous system based on wavelet-fractal technique. Methods: The wavelet transform was employed to decompose the original signal and obtain 4 sub-patterns. The dividing fractal dimensions of these sub-patterns were computed. A knn-classier was used to classify feature vectors. Results: Not all the elements in feature vector DimDC were very powerful for this pattern recognition problem through the empirical study of noise signals. The most effective feature vector was defined as DimDC= (d3:d4) above. Conclusion:Wavelet fractal algorithm has high accuracy and provides a powerful tool for clinical application.
文摘The aim of the study was to determine the harmfulness of leaf miners and their species composition on winter wheat for the improvement of methods to control them. In order to determine the dates of the treatments, it was necessary to catch adult flies. The researchers used yellow 25 x 40 cm sticky traps placed on three control plots to catch the adults. Monitoring of cereal leaf miners flights in winter wheat was carried out in Babor6wko （greater Poland voivodeship）. Yellow traps were placed above the tops of wheat during vegetation period. The number of damaged wheat stems was recorded. Fluctuations in weather conditions during the research affected the dynamics of leaf miner flies considerably. The maximum flights of leaf miner flies on winter wheat crops in years of the studies took place in May. The dynamics of leaf miners flights were different in growing season 2008 and 2009. The most common species were： Chromatomyia nigra （Ztt.）, Chromatomyia fuscula （Ztt.） and Poemyza superciliosa （Ztt.）. It was also discovered that the species composition of Agromyzidae damaging the winter wheat, changes in particular years. The results differ from the results of the previous research, which the dominant species were Phytomyza nigra （Mg.） and Agromyza ambiqua （FII.）.
