This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strate...This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strategies and highlight the current limitations and challenges in surface and bulk processing.Specifically,we emphasize the delicate balance between high-fidelity beam shaping and energy efficiency,both critical for surface and bulk processing applications.Given the inherent physical limitations of spatial light modulators such as spatial resolution,fill factor,and phase modulation range.We explore techniques developed to bridge the gap between desired intensity distributions and actual experimental beam profiles.We present various laser light modulation technologies and the main algorithmic strategies for obtaining modulation patterns.The paper includes application examples across a wide range of fields,from surgery to surface structuring,cutting,bulk photo-inscription of optical functions,and additive manufacturing,highlighting the significant enhancements in processing speed and precision due to spatial beam shaping.The diverse applications and the technological limitations underscore the need for adapted modulation pattern calculation methods.We discuss several advancements addressing these challenges,involving both experimental and algorithmic developments,including the recent incorporation of artificial intelligence.Additionally,we cover recent progress in phase and pulse front control based on spatial modulators,which introduces an extra control parameter for light excitation with high potential for achieving more controlled processing outcomes.展开更多
This article elaborated the characteristics of settlement shape in detail with examples. Aiming at the negative effects on settlement shape by construction, we put forward some measures, such as respect for ecological...This article elaborated the characteristics of settlement shape in detail with examples. Aiming at the negative effects on settlement shape by construction, we put forward some measures, such as respect for ecological environment, selection mode of space development, protection of historical features, and excavation of culture connotation, so as to realize the protection of settlement shape.展开更多
In this study, we investigated the natural growth of Haloxylon ammodendron forest in Moso Bay, southwest of Gurbantunggut Desert. Random sample analysis was used to analyze the spatial point pattern performance of Hal...In this study, we investigated the natural growth of Haloxylon ammodendron forest in Moso Bay, southwest of Gurbantunggut Desert. Random sample analysis was used to analyze the spatial point pattern performance of Haloxylon ammodendron population. ArcGIS software was used to summarize and analyze the spatial point pattern response of Haloxylon ammodendron population. The results showed that: 1) There were significant differences in the performance of point pattern analysis among different random quadrants. The paired t-test for variance mean ratio showed that the P values were 0.048, 0.004 and 0.301 respectively, indicating that the influence of quadrat shape on the performance of point pattern analysis was significant under the condition of the same optimal quadrat area. 2) The comparative analysis of square shapes shows that circular square is the best, square and regular hexagonal square are the second, and there is no significant difference between square and regular hexagonal square. 3) The number of samples plays a decisive role in spatial point pattern analysis. Insufficient sample size will lead to unstable results. With the increase of the number of samples to more than 120, the V value and P value curves will eventually stabilize. That is, stable spatial point pattern analysis results are closely related to the increase of the number of samples in random sample square analysis.展开更多
In allusion to the deficient feature of product information in conceptualdesign, a framework of deficient information modeling for conceptual shape design is put forward,which includes qualitative shape modeling (a qu...In allusion to the deficient feature of product information in conceptualdesign, a framework of deficient information modeling for conceptual shape design is put forward,which includes qualitative shape modeling (a qualitative solid model), uncertain shape modeling (anuncertain relation model) and imprecise shape modeling (an imprecise region model). In theframework, the qualitative solid model is the core, which represents qualitatively (using symbols)the conceptual shapes of mechanical products. The uncertain relation model regarding domainrelations as objects and the imprecise region model regarding domains as objects are used to dealwith the uncertain and imprecise issues respectively, which arise from qualitative shape modeling orexist in product information itself.展开更多
目的红外小目标检测旨在从复杂背景中准确识别和定位弱小红外目标,在海上侦查、军事救援等任务中具有重要的应用前景。然而,受限于红外图像中目标尺寸小、对比度低等因素,当前的检测方法仍难以实现检测精度与误报率之间的平衡。针对上...目的红外小目标检测旨在从复杂背景中准确识别和定位弱小红外目标,在海上侦查、军事救援等任务中具有重要的应用前景。然而,受限于红外图像中目标尺寸小、对比度低等因素,当前的检测方法仍难以实现检测精度与误报率之间的平衡。针对上述问题,提出一种基于选择性注意力的红外小目标检测网络(selective attentionbased network for infrared small target detection,SANet)。方法具体而言,设计了双路径语义感知模块,用于增强网络对弱小目标的感知能力。该模块融合了标准卷积与风车型卷积两种路径,兼顾局部空间一致性与全局上下文感知能力,并进一步引入空间/通道注意力机制以细化特征表达,从而有效提升了目标与背景的可区分性。此外,为克服U-Net中静态跳跃连接在特征融合中的局限性,进一步提出了选择性注意力融合模块。该模块基于空间动态权重机制实现跨尺度特征的自适应融合,能够根据空间显著性选择性增强关键区域,从而提升对真实目标与误报的辨识能力。结果在3个公开基准数据集上的实验结果验证了所提出的SANet在交并比(intersection over union,IoU)、nIoU、P_(d)和F_(a)4个指标上均优于现有先进方法,其中,本文方法的IoU指标在上述基准数据集上比次优方法分别提升1.93%、4.32%和2.21%。结论SANet有效增强了网络对小目标的感知能力、关键特征的表达能力以及背景干扰的抑制能力。源代码可以在https://gitcode.com/m0_61988291/SANet上获取。展开更多
Today global warming has become one of the most important concerns of environmental science. The redundancy of greenhouse gases in the atmosphere is known as a major factor in this phenomenon. These gases contain wate...Today global warming has become one of the most important concerns of environmental science. The redundancy of greenhouse gases in the atmosphere is known as a major factor in this phenomenon. These gases contain water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The CO2?gas is one of their most effective among these gases. According to scientific warnings, the amount of CO2?gases in the atmosphere has increased by 40% to 45% over the last 50 years. Reducing the abundant gas in the atmosphere requires a good knowledge of related factors involved, including sources that emit gases into the atmosphere and sinks that absorb the gas from the atmosphere. The amount of CO2?gas in the atmosphere has been accurately measured in previous years with great certainty. But the predicted values of emissions from sources and removals by sinks have large ambiguities. As studies show, even the computed residuals trends (which is obtained by subtracting the amounts of sinks from sources) strongly disagree with the trends of the existence of CO2?in the atmosphere. This study as a preliminary review, proposes a method to identify the locations of sources and sinks of carbon dioxide using global statistical information and adding spatial analysis approaches. By applying this method to the data observed from 2000 to 2011 and the extraction of likely sources and sinks, the region of the Black Sea, near Romania recognized as one of the strong points issued and Bukit Kototabang near Indonesia acknowledged as an Impressive CO2?absorption zone.展开更多
A new concept of characteristic scanning radial (CSR) is proposed for thesegmented image on the basis of two shape-specific points of its shape-objects. Subsequently, twocharacteristic attribute sequences (CAS) of rel...A new concept of characteristic scanning radial (CSR) is proposed for thesegmented image on the basis of two shape-specific points of its shape-objects. Subsequently, twocharacteristic attribute sequences (CAS) of relative distance and relative direction are derived torepresent the spatial orientation relationships among objects of the image. A novel image retrievalalgorithm is presented using these two CASs. The proposed retrieval approach not only satisfies thetransformational invariance, butalso attains the quantitative comparison of matching. Experimentsidentify the effectiveness and efficiency of the algorithm adequately.展开更多
基金supported by the French ANRT agence nationale de la recherche technologique under the CIFRE conventions industrielles de formation par la recherche framework.
文摘This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strategies and highlight the current limitations and challenges in surface and bulk processing.Specifically,we emphasize the delicate balance between high-fidelity beam shaping and energy efficiency,both critical for surface and bulk processing applications.Given the inherent physical limitations of spatial light modulators such as spatial resolution,fill factor,and phase modulation range.We explore techniques developed to bridge the gap between desired intensity distributions and actual experimental beam profiles.We present various laser light modulation technologies and the main algorithmic strategies for obtaining modulation patterns.The paper includes application examples across a wide range of fields,from surgery to surface structuring,cutting,bulk photo-inscription of optical functions,and additive manufacturing,highlighting the significant enhancements in processing speed and precision due to spatial beam shaping.The diverse applications and the technological limitations underscore the need for adapted modulation pattern calculation methods.We discuss several advancements addressing these challenges,involving both experimental and algorithmic developments,including the recent incorporation of artificial intelligence.Additionally,we cover recent progress in phase and pulse front control based on spatial modulators,which introduces an extra control parameter for light excitation with high potential for achieving more controlled processing outcomes.
基金Supported by the 11th 5-year Scientific Supporting Project Fund of the Ministry of Science and Technology(2006BAJ01A12-06)the 11th 5-years Planning Philosophy and Social Science Project of Sichuan Province(SC06B014)~~
文摘This article elaborated the characteristics of settlement shape in detail with examples. Aiming at the negative effects on settlement shape by construction, we put forward some measures, such as respect for ecological environment, selection mode of space development, protection of historical features, and excavation of culture connotation, so as to realize the protection of settlement shape.
文摘In this study, we investigated the natural growth of Haloxylon ammodendron forest in Moso Bay, southwest of Gurbantunggut Desert. Random sample analysis was used to analyze the spatial point pattern performance of Haloxylon ammodendron population. ArcGIS software was used to summarize and analyze the spatial point pattern response of Haloxylon ammodendron population. The results showed that: 1) There were significant differences in the performance of point pattern analysis among different random quadrants. The paired t-test for variance mean ratio showed that the P values were 0.048, 0.004 and 0.301 respectively, indicating that the influence of quadrat shape on the performance of point pattern analysis was significant under the condition of the same optimal quadrat area. 2) The comparative analysis of square shapes shows that circular square is the best, square and regular hexagonal square are the second, and there is no significant difference between square and regular hexagonal square. 3) The number of samples plays a decisive role in spatial point pattern analysis. Insufficient sample size will lead to unstable results. With the increase of the number of samples to more than 120, the V value and P value curves will eventually stabilize. That is, stable spatial point pattern analysis results are closely related to the increase of the number of samples in random sample square analysis.
基金National Natural Science Foundation of China (No.59990470)
文摘In allusion to the deficient feature of product information in conceptualdesign, a framework of deficient information modeling for conceptual shape design is put forward,which includes qualitative shape modeling (a qualitative solid model), uncertain shape modeling (anuncertain relation model) and imprecise shape modeling (an imprecise region model). In theframework, the qualitative solid model is the core, which represents qualitatively (using symbols)the conceptual shapes of mechanical products. The uncertain relation model regarding domainrelations as objects and the imprecise region model regarding domains as objects are used to dealwith the uncertain and imprecise issues respectively, which arise from qualitative shape modeling orexist in product information itself.
文摘目的红外小目标检测旨在从复杂背景中准确识别和定位弱小红外目标,在海上侦查、军事救援等任务中具有重要的应用前景。然而,受限于红外图像中目标尺寸小、对比度低等因素,当前的检测方法仍难以实现检测精度与误报率之间的平衡。针对上述问题,提出一种基于选择性注意力的红外小目标检测网络(selective attentionbased network for infrared small target detection,SANet)。方法具体而言,设计了双路径语义感知模块,用于增强网络对弱小目标的感知能力。该模块融合了标准卷积与风车型卷积两种路径,兼顾局部空间一致性与全局上下文感知能力,并进一步引入空间/通道注意力机制以细化特征表达,从而有效提升了目标与背景的可区分性。此外,为克服U-Net中静态跳跃连接在特征融合中的局限性,进一步提出了选择性注意力融合模块。该模块基于空间动态权重机制实现跨尺度特征的自适应融合,能够根据空间显著性选择性增强关键区域,从而提升对真实目标与误报的辨识能力。结果在3个公开基准数据集上的实验结果验证了所提出的SANet在交并比(intersection over union,IoU)、nIoU、P_(d)和F_(a)4个指标上均优于现有先进方法,其中,本文方法的IoU指标在上述基准数据集上比次优方法分别提升1.93%、4.32%和2.21%。结论SANet有效增强了网络对小目标的感知能力、关键特征的表达能力以及背景干扰的抑制能力。源代码可以在https://gitcode.com/m0_61988291/SANet上获取。
文摘Today global warming has become one of the most important concerns of environmental science. The redundancy of greenhouse gases in the atmosphere is known as a major factor in this phenomenon. These gases contain water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The CO2?gas is one of their most effective among these gases. According to scientific warnings, the amount of CO2?gases in the atmosphere has increased by 40% to 45% over the last 50 years. Reducing the abundant gas in the atmosphere requires a good knowledge of related factors involved, including sources that emit gases into the atmosphere and sinks that absorb the gas from the atmosphere. The amount of CO2?gas in the atmosphere has been accurately measured in previous years with great certainty. But the predicted values of emissions from sources and removals by sinks have large ambiguities. As studies show, even the computed residuals trends (which is obtained by subtracting the amounts of sinks from sources) strongly disagree with the trends of the existence of CO2?in the atmosphere. This study as a preliminary review, proposes a method to identify the locations of sources and sinks of carbon dioxide using global statistical information and adding spatial analysis approaches. By applying this method to the data observed from 2000 to 2011 and the extraction of likely sources and sinks, the region of the Black Sea, near Romania recognized as one of the strong points issued and Bukit Kototabang near Indonesia acknowledged as an Impressive CO2?absorption zone.
文摘A new concept of characteristic scanning radial (CSR) is proposed for thesegmented image on the basis of two shape-specific points of its shape-objects. Subsequently, twocharacteristic attribute sequences (CAS) of relative distance and relative direction are derived torepresent the spatial orientation relationships among objects of the image. A novel image retrievalalgorithm is presented using these two CASs. The proposed retrieval approach not only satisfies thetransformational invariance, butalso attains the quantitative comparison of matching. Experimentsidentify the effectiveness and efficiency of the algorithm adequately.
