In the era of green logistics,digital transformation has become an effective means for the logistics industry’s high-quality development.Using listed companies in China’s logistics industry from 2010 to 2021 as the ...In the era of green logistics,digital transformation has become an effective means for the logistics industry’s high-quality development.Using listed companies in China’s logistics industry from 2010 to 2021 as the research samples,this paper conducts an empirical test on the impact of the digital transformation of logistics enterprises on their green in-novation.Specifically,enterprise digital transformation indicators are constructed through the text analysis method,and the fixed-effects model is applied for analysis.The results indicate that the digital transformation of logistics enterprises has a significant promoting effect on their green innovation;the promoting effect of the digital transformation of logistics enterprises on green innovation is primarily achieved by easing corporate financing constraints and reducing corporate en-vironmental uncertainty;and the impact of digital transformation on green innovation is geographically heterogeneous.展开更多
Redox flow batteries have gained wide attention at home and abroad as a long-duration energy storage technology with the advantages of high safety,long lifespan,mutual independence of capacity and power,and easy recyc...Redox flow batteries have gained wide attention at home and abroad as a long-duration energy storage technology with the advantages of high safety,long lifespan,mutual independence of capacity and power,and easy recycling.However,the current battery management technology faces significant challenges,and there is room for development.Digital twin(DT),as a technology that collectively senses,evaluates,predicts,and optimizes characteristics,is promising to contribute to redox flow batteries’operation,maintenance,and management.This paper begins with a brief description of redox flow batteries,followed by a short explanation of the concept and application of DTs.DTs have already made some progress in the field of batteries,and can be applied to solve the problems of redox flow batteries in terms of thermal management and system optimization.Finally,the paper analyzes the combination of redox flow battery and DT architecture,which is expected to contribute to developing DT technology for redox flow batteries.展开更多
为探索GS1 Digital Link技术在产品物流中的应用潜力,分析研究了GS1系统和GS1 Digital Link的基本结构、编码特点以及技术优势,充分利用GS1 Digital Link技术可以为产品从源头到零售整个物流过程提供相关对象的Web地址编码的特点,以鲜...为探索GS1 Digital Link技术在产品物流中的应用潜力,分析研究了GS1系统和GS1 Digital Link的基本结构、编码特点以及技术优势,充分利用GS1 Digital Link技术可以为产品从源头到零售整个物流过程提供相关对象的Web地址编码的特点,以鲜活大闸蟹物流过程为例,构建了基于GS1 Digital Link的鲜活大闸蟹Web编码,为实现产品营销与追溯提供了标准化、动态化、多样化的编码数据支撑。展开更多
Color,classified as warm and cool colors,impacts consumers’product selection.How the warm and cool di-mensions of colors in polychromatic pictures impact consumers’behavior in e-commerce platforms remains unexplored...Color,classified as warm and cool colors,impacts consumers’product selection.How the warm and cool di-mensions of colors in polychromatic pictures impact consumers’behavior in e-commerce platforms remains unexplored.This research examines the influences of warm and cool color combinations on consumers’liking using polychromatic stimuli in a digital reading context using empirical evidence from over 200000 exposures to 423 books.As a result,warm and cool colors(vs.neutral colors)can enhance the click-through rate,and the romance theme of novels can enhance the positive effect to consumers of warm colors(vs.neutral colors).This research extends the findings using monochromatic stimuli and indicates a theme-based visual-product attribute congruence that enhances consumers’trial-reading choice on the digital reading platform.展开更多
Ti(C,N)基金属陶瓷显微组织及相界面较复杂,需要一种简便、精确的定量金相方法来辅助研究.采用功能强大的Gatan Digital Micrograph软件对不同纳米添加量Ti(C,N)基金属陶瓷显微组织进行背底消除、滤波、二值化及图像形态学处理,分析可...Ti(C,N)基金属陶瓷显微组织及相界面较复杂,需要一种简便、精确的定量金相方法来辅助研究.采用功能强大的Gatan Digital Micrograph软件对不同纳米添加量Ti(C,N)基金属陶瓷显微组织进行背底消除、滤波、二值化及图像形态学处理,分析可得到该金相图中的一些金相特征参数.对不同纳米添加量Ti(C,N)基金属陶瓷中硬质相进行了综合分析,结果表明,利用Gatan Digi-tal Micrograph软件实现Ti(C,N)基金属陶瓷显微组织的分析测量是完全可行的,能有效地提高工作效率及得到直观、准确的结果,也可定量地得到随纳米粉添加量的不断增加,硬质相颗粒的总体积不断减少,平均粒径也在不断减小.展开更多
A novel copyright protection scheme for digital content is presented, which is a private watermarking scheme based on the watermark embedding in the DCT domain and watermark extraction Using independent component anal...A novel copyright protection scheme for digital content is presented, which is a private watermarking scheme based on the watermark embedding in the DCT domain and watermark extraction Using independent component analysis （ICA）. The system includes the key for watermark extraction and the host image. The algorithm splits the original image into blocks and classifies these blocks based on visual masking, that is, noise visibility function （NVF）. Watermark components with different strength are inserted into chosen direct current components of DCT coefficients according to the classifier. The watermark extraction is based on the characteristic of the statistic independence of the host image, watermark and key. Principle component analysis （PCA） whitening process and FastICA techniques are introduced to ensure a blind watermark extraction without requiring the original image. Experirnental results show the proposed technique is robust under attacks such as image filtering and adding noise, cropping and resizing. In addition, the proposed private watermarking system can be improved to the application of the DTV content protection system.展开更多
Digital receivers have become more and more popular in radar, communication, and electric warfare for the advantages compared with their analog counterparts. But conventional digital receivers have been generally cons...Digital receivers have become more and more popular in radar, communication, and electric warfare for the advantages compared with their analog counterparts. But conventional digital receivers have been generally considered impractical for bandwidth greater than several hundreds MHz. To extend receiver bandwidth, decrease data rate and save hardware resources, three novel structures are proposed. They decimate the data stream prior to mixing and filtering, then process the multiple decimated streams in parallel at a lower rate. Consequently it is feasible to realize wideband receivers on the current ASIC devices. A design example and corresponding simulation results are demonstrated to evaluate the proposed structures.展开更多
This article deals with two important issues in digital filter implementation： roundoff noise and limit cycles. A novel class of robust state-space realizations, called normal realizations, is derived and characteriz...This article deals with two important issues in digital filter implementation： roundoff noise and limit cycles. A novel class of robust state-space realizations, called normal realizations, is derived and characterized. It is seen that these realizations are free of limit cycles. Another interesting property of the normal realizations is that they yield a minimal error propagation gain. The optimal realization problem, defined as to find those normal realizations that minimize roundoff noise gain, is formulated and solved analytically. A design example is presented to demonstrate the behavior of the optimal normal realizations and to compare them with several well-known digital filter realizations in terms of minimizing the roundoff noise and the error propagation.展开更多
Digital elevation modeling(DEM)是基础地理数据之一,从其中可以提取多种地形参数,DEM不确定性对提取的地形参数具有一定的影响.选择坡度、上坡集水面积和地形指数作为研究对象,在DEM不确定性模拟的基础上,研究DEM不确定性对地形参数...Digital elevation modeling(DEM)是基础地理数据之一,从其中可以提取多种地形参数,DEM不确定性对提取的地形参数具有一定的影响.选择坡度、上坡集水面积和地形指数作为研究对象,在DEM不确定性模拟的基础上,研究DEM不确定性对地形参数影响的空间分布特征.研究发现:DEM不确定性对坡度的影响没有明显的空间分布特征,对上坡集水面积和地形指数具有明显的空间分布特征.DEM不确定性对上坡集水面积影响的空间分布特征为:总体上分布均匀,在河道及附近、水库区域影响大于其它地区;DEM不确定性对地形指数影响的空间分布特征为:总体上分布均匀,在河道及附近、水库、平地地区影响大于其它地区.不同DEM不确定性程度对地形参数影响的空间分布特征相似.展开更多
An online pulse interleaving scheduling algorithm is proposed for a solution to the task scheduling problem in the digital array radar(DAR). The full DAR task structure is explicitly considered in a way that the waiti...An online pulse interleaving scheduling algorithm is proposed for a solution to the task scheduling problem in the digital array radar(DAR). The full DAR task structure is explicitly considered in a way that the waiting duration is able to be utilized to transmit or receive subtasks, namely the pulse interleaving,as well as the receiving durations of different tasks are able to be overlapped. The algorithm decomposes the pulse interleaving scheduling analysis into the time constraint check and the energy constraint check, and schedules online all kinds of tasks that are able to be interleaved. Thereby the waiting duration and the receiving duration in the DAR task are both fully utilized. The simulation results verify the performance improvement and the high efficiency of the proposed algorithm compared with the existing ones.展开更多
Two signature systems based on smart cards and fingerprint features are proposed. In one signature system, the cryptographic key is stored in the smart card and is only accessible when the signer＇s extracted fingerpr...Two signature systems based on smart cards and fingerprint features are proposed. In one signature system, the cryptographic key is stored in the smart card and is only accessible when the signer＇s extracted fingerprint features match his stored template. To resist being tampered on public channel, the user＇s message and the signed message are encrypted by the signer＇s public key and the user＇s public key, respectively. In the other signature system, the keys are generated by combining the signer＇s fingerprint features, check bits, and a rememberable key, and there are no matching process and keys stored on the smart card. Additionally, there is generally more than one public key in this system, that is, there exist some pseudo public keys except a real one.展开更多
An approach is proposed to realize a digital channelized receiver in the fractional Fourier domain （FRFD） for signal intercept applications. The presented architecture can be considered as a generalization of that i...An approach is proposed to realize a digital channelized receiver in the fractional Fourier domain （FRFD） for signal intercept applications. The presented architecture can be considered as a generalization of that in the traditional Fourier domain. Since the linear frequency modulation （LFM） signal has a good energy concentration in the FRFD, by choosing an appropriate fractional Fourier transform （FRFT） order, the presented architecture can concentrate the broadband LFM signal into only one sub-channel and that will prevent it from crossing several sub-channels. Thus the performance of the signal detection and parameter estimation after the sub-channel output will be improved significantly. The computational complexity is reduced enormously due to the implementation of the polyphase filter bank decomposition, thus the proposed architecture can be realized as efficiently as in the Fourier domain. The related simulation results are presented to verify the validity of the theories and methods involved in this paper.展开更多
In order to protect copyright of digital images,a new robust digital image watermarking algorithm based on chaotic system and QR factorization was proposed.The host images were firstly divided into blocks with same si...In order to protect copyright of digital images,a new robust digital image watermarking algorithm based on chaotic system and QR factorization was proposed.The host images were firstly divided into blocks with same size,then QR factorization was performed on each block.Pseudorandom circular chain(PCC) generated by logistic mapping(LM) was applied to select the embedding blocks for enhancing the security of the scheme.The first column coefficients in Q matrix of chosen blocks were modified to embed watermarks without causing noticeable artifacts.Watermark extraction procedure was performed without the original cover image.The experimental results demonstrate that the watermarked images have good visual quality and this scheme is better than the existing techniques,especially when the image is attacked by cropping,noise pollution and so on.Analysis and discussion on robustness and security issues were also presented.展开更多
A new meso-mechanical testing scheme based on SEM was developed to carry out the experiment of microfracturing process of rocks. The microfracturing process of the pre-crack marble sample on surrounding rock in the im...A new meso-mechanical testing scheme based on SEM was developed to carry out the experiment of microfracturing process of rocks. The microfracturing process of the pre-crack marble sample on surrounding rock in the immerged Long-big tunnel in Jinping Cascade II Hydropower Station under uniaxial compression was recorded by using the testing scheme. According to the stereology theory, the propagation and coalescent of cracks at meso-scale were quantitatively investigated with digital technology. Therefore, the basic geometric information of rock microcracks such as area, angle, length, width, perimeter, was obtained from binary images after segmentation. The failure mechanism of specimen under uniaxial compression with the quantitative information was studied from macro and microscopic point of view. The results show that the image of microfracturing process of the specimen can be observed and recorded digitally. During the damage of the specimen, the distribution of microcracks in the specimen is still subjected to exponential distribution with some microcracks concentrated in certain regions. Finally, the change law of the fractal dimension of the local element in marble sample under different external load conditions is obtained by means of the statistical calculation of the fractal dimension.展开更多
基金supported by the National Natural Science Foundation of China(72374061,72204243)the Ministry of Education’s Humanities and Social Science Research Youth Fund Project(20YJC630138,22YJC630056)+1 种基金Anhui Provincial Natural Science Foundation(2208085UD02)New Liberal Arts Fund Expansion Project of University of Science and Technology of China(FSSF-A-230317).
文摘In the era of green logistics,digital transformation has become an effective means for the logistics industry’s high-quality development.Using listed companies in China’s logistics industry from 2010 to 2021 as the research samples,this paper conducts an empirical test on the impact of the digital transformation of logistics enterprises on their green in-novation.Specifically,enterprise digital transformation indicators are constructed through the text analysis method,and the fixed-effects model is applied for analysis.The results indicate that the digital transformation of logistics enterprises has a significant promoting effect on their green innovation;the promoting effect of the digital transformation of logistics enterprises on green innovation is primarily achieved by easing corporate financing constraints and reducing corporate en-vironmental uncertainty;and the impact of digital transformation on green innovation is geographically heterogeneous.
基金Supported by the Special Educating Project of the Talent for Carbon Peak and Carbon Neutrality of University of Chinese Academy of Sciences(E3E56501A2)。
文摘Redox flow batteries have gained wide attention at home and abroad as a long-duration energy storage technology with the advantages of high safety,long lifespan,mutual independence of capacity and power,and easy recycling.However,the current battery management technology faces significant challenges,and there is room for development.Digital twin(DT),as a technology that collectively senses,evaluates,predicts,and optimizes characteristics,is promising to contribute to redox flow batteries’operation,maintenance,and management.This paper begins with a brief description of redox flow batteries,followed by a short explanation of the concept and application of DTs.DTs have already made some progress in the field of batteries,and can be applied to solve the problems of redox flow batteries in terms of thermal management and system optimization.Finally,the paper analyzes the combination of redox flow battery and DT architecture,which is expected to contribute to developing DT technology for redox flow batteries.
文摘为探索GS1 Digital Link技术在产品物流中的应用潜力,分析研究了GS1系统和GS1 Digital Link的基本结构、编码特点以及技术优势,充分利用GS1 Digital Link技术可以为产品从源头到零售整个物流过程提供相关对象的Web地址编码的特点,以鲜活大闸蟹物流过程为例,构建了基于GS1 Digital Link的鲜活大闸蟹Web编码,为实现产品营销与追溯提供了标准化、动态化、多样化的编码数据支撑。
基金supported by the National Natural Science Foundation of China(72072169).
文摘Color,classified as warm and cool colors,impacts consumers’product selection.How the warm and cool di-mensions of colors in polychromatic pictures impact consumers’behavior in e-commerce platforms remains unexplored.This research examines the influences of warm and cool color combinations on consumers’liking using polychromatic stimuli in a digital reading context using empirical evidence from over 200000 exposures to 423 books.As a result,warm and cool colors(vs.neutral colors)can enhance the click-through rate,and the romance theme of novels can enhance the positive effect to consumers of warm colors(vs.neutral colors).This research extends the findings using monochromatic stimuli and indicates a theme-based visual-product attribute congruence that enhances consumers’trial-reading choice on the digital reading platform.
文摘Ti(C,N)基金属陶瓷显微组织及相界面较复杂,需要一种简便、精确的定量金相方法来辅助研究.采用功能强大的Gatan Digital Micrograph软件对不同纳米添加量Ti(C,N)基金属陶瓷显微组织进行背底消除、滤波、二值化及图像形态学处理,分析可得到该金相图中的一些金相特征参数.对不同纳米添加量Ti(C,N)基金属陶瓷中硬质相进行了综合分析,结果表明,利用Gatan Digi-tal Micrograph软件实现Ti(C,N)基金属陶瓷显微组织的分析测量是完全可行的,能有效地提高工作效率及得到直观、准确的结果,也可定量地得到随纳米粉添加量的不断增加,硬质相颗粒的总体积不断减少,平均粒径也在不断减小.
基金This project was supported by the Digital TV Special Foundation of National Development and Reform Commission ofChina (040313) Home Coming Scholars Science Activity Foundation of Ministry of Personnel (20041231) the Graduate In-novation Foundation of Xidian University (innovaion 0509)
文摘A novel copyright protection scheme for digital content is presented, which is a private watermarking scheme based on the watermark embedding in the DCT domain and watermark extraction Using independent component analysis （ICA）. The system includes the key for watermark extraction and the host image. The algorithm splits the original image into blocks and classifies these blocks based on visual masking, that is, noise visibility function （NVF）. Watermark components with different strength are inserted into chosen direct current components of DCT coefficients according to the classifier. The watermark extraction is based on the characteristic of the statistic independence of the host image, watermark and key. Principle component analysis （PCA） whitening process and FastICA techniques are introduced to ensure a blind watermark extraction without requiring the original image. Experirnental results show the proposed technique is robust under attacks such as image filtering and adding noise, cropping and resizing. In addition, the proposed private watermarking system can be improved to the application of the DTV content protection system.
基金This project was supported by the National Defense I mportant Research Foundation of China(03413070506)
文摘Digital receivers have become more and more popular in radar, communication, and electric warfare for the advantages compared with their analog counterparts. But conventional digital receivers have been generally considered impractical for bandwidth greater than several hundreds MHz. To extend receiver bandwidth, decrease data rate and save hardware resources, three novel structures are proposed. They decimate the data stream prior to mixing and filtering, then process the multiple decimated streams in parallel at a lower rate. Consequently it is feasible to realize wideband receivers on the current ASIC devices. A design example and corresponding simulation results are demonstrated to evaluate the proposed structures.
基金the National Nature Science Foundation of China (60774021)
文摘This article deals with two important issues in digital filter implementation： roundoff noise and limit cycles. A novel class of robust state-space realizations, called normal realizations, is derived and characterized. It is seen that these realizations are free of limit cycles. Another interesting property of the normal realizations is that they yield a minimal error propagation gain. The optimal realization problem, defined as to find those normal realizations that minimize roundoff noise gain, is formulated and solved analytically. A design example is presented to demonstrate the behavior of the optimal normal realizations and to compare them with several well-known digital filter realizations in terms of minimizing the roundoff noise and the error propagation.
文摘An online pulse interleaving scheduling algorithm is proposed for a solution to the task scheduling problem in the digital array radar(DAR). The full DAR task structure is explicitly considered in a way that the waiting duration is able to be utilized to transmit or receive subtasks, namely the pulse interleaving,as well as the receiving durations of different tasks are able to be overlapped. The algorithm decomposes the pulse interleaving scheduling analysis into the time constraint check and the energy constraint check, and schedules online all kinds of tasks that are able to be interleaved. Thereby the waiting duration and the receiving duration in the DAR task are both fully utilized. The simulation results verify the performance improvement and the high efficiency of the proposed algorithm compared with the existing ones.
基金This project was supported by the National Science Foundation of China (60763009)China Postdoctoral Science Foundation (2005038041)Hainan Natural Science Foundation (80528).
文摘Two signature systems based on smart cards and fingerprint features are proposed. In one signature system, the cryptographic key is stored in the smart card and is only accessible when the signer＇s extracted fingerprint features match his stored template. To resist being tampered on public channel, the user＇s message and the signed message are encrypted by the signer＇s public key and the user＇s public key, respectively. In the other signature system, the keys are generated by combining the signer＇s fingerprint features, check bits, and a rememberable key, and there are no matching process and keys stored on the smart card. Additionally, there is generally more than one public key in this system, that is, there exist some pseudo public keys except a real one.
基金supported by the Program for New Century Excellent Talents in University(NCET-06-0921)
文摘An approach is proposed to realize a digital channelized receiver in the fractional Fourier domain （FRFD） for signal intercept applications. The presented architecture can be considered as a generalization of that in the traditional Fourier domain. Since the linear frequency modulation （LFM） signal has a good energy concentration in the FRFD, by choosing an appropriate fractional Fourier transform （FRFT） order, the presented architecture can concentrate the broadband LFM signal into only one sub-channel and that will prevent it from crossing several sub-channels. Thus the performance of the signal detection and parameter estimation after the sub-channel output will be improved significantly. The computational complexity is reduced enormously due to the implementation of the polyphase filter bank decomposition, thus the proposed architecture can be realized as efficiently as in the Fourier domain. The related simulation results are presented to verify the validity of the theories and methods involved in this paper.
基金Project(2007AA01Z241-2) supported by the National High-tech Research and Development Program of ChinaProject(2006XM002) supported by Beijing Jiaotong University Science Foundation,ChinaProject(0910KYZY55) supported by the Fundamental Research Funds for the Central University in China
文摘In order to protect copyright of digital images,a new robust digital image watermarking algorithm based on chaotic system and QR factorization was proposed.The host images were firstly divided into blocks with same size,then QR factorization was performed on each block.Pseudorandom circular chain(PCC) generated by logistic mapping(LM) was applied to select the embedding blocks for enhancing the security of the scheme.The first column coefficients in Q matrix of chosen blocks were modified to embed watermarks without causing noticeable artifacts.Watermark extraction procedure was performed without the original cover image.The experimental results demonstrate that the watermarked images have good visual quality and this scheme is better than the existing techniques,especially when the image is attacked by cropping,noise pollution and so on.Analysis and discussion on robustness and security issues were also presented.
基金Projects(50674040, 50539090) supported by the National Natural Science Foundation of ChinaProject(CX07B_128z) supported by the Cultivate Creative Postgraduate Foundation of Jiangsu Province, China
文摘A new meso-mechanical testing scheme based on SEM was developed to carry out the experiment of microfracturing process of rocks. The microfracturing process of the pre-crack marble sample on surrounding rock in the immerged Long-big tunnel in Jinping Cascade II Hydropower Station under uniaxial compression was recorded by using the testing scheme. According to the stereology theory, the propagation and coalescent of cracks at meso-scale were quantitatively investigated with digital technology. Therefore, the basic geometric information of rock microcracks such as area, angle, length, width, perimeter, was obtained from binary images after segmentation. The failure mechanism of specimen under uniaxial compression with the quantitative information was studied from macro and microscopic point of view. The results show that the image of microfracturing process of the specimen can be observed and recorded digitally. During the damage of the specimen, the distribution of microcracks in the specimen is still subjected to exponential distribution with some microcracks concentrated in certain regions. Finally, the change law of the fractal dimension of the local element in marble sample under different external load conditions is obtained by means of the statistical calculation of the fractal dimension.
