The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration product...The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration products, quantity, pore structure and morphology were measured by X-ray diffraction(XRD), thermalgravity-differential thermal analysis(TG-DTA), mercury intrusion porosimetry(MIP) and scanning electron microscopy(SEM), respectively. The results indicate that grinding could not only improve the physical properties of the low quality fly ash on particle effect, but also improve hydration properties of the cementitious system from various aspects compared with raw low quality fly ash(RLFA). At the early stage of hydration, the low quanlity fly ash acts as almost inert material; but then at the later stage, high chemical activity, especially for ground low quality fly ash(GLFA), could be observed. It can accelerate the formation of hydration products containing more chemical bonded water, resulting in higher degree of cement hydration, thus denser microstructure and more reasonable pore size distribution, but the hydration heat in total is reduced. It can also delay the induction period, but the accelerating period is shortened and there is little influence on the second exothermic peak.展开更多
To combat packet loss and realize robust video transmission over Intemet and wireless networks, a new multiple description （MD） video coding method is proposed. In the method, two descriptions for each video frame i...To combat packet loss and realize robust video transmission over Intemet and wireless networks, a new multiple description （MD） video coding method is proposed. In the method, two descriptions for each video frame is first created by group of blocks （GOB） alternation. Motion information is then duplicated in both the descriptions and a process called low quality macroblock update is designed to redundantly encode textures in each frame using standard bit stream syntax. In this way, the output bit streams are standard compliant and better trade-offs between redundancy and single charmel reconstruction distortion are achieved. The proposed method has much better performance than the well-known MD transform coding （MDTC） method both in terms of redundancy rate distortion, and in the packet loss scenario.展开更多
This paper proposes a novel method for the automatic diagnosis of keratitis using feature vector quantization and self-attention mechanisms(ADK_FVQSAM).First,high-level features are extracted using the DenseNet121 bac...This paper proposes a novel method for the automatic diagnosis of keratitis using feature vector quantization and self-attention mechanisms(ADK_FVQSAM).First,high-level features are extracted using the DenseNet121 backbone network,followed by adaptive average pooling to scale the features to a fixed length.Subsequently,product quantization with residuals(PQR)is applied to convert continuous feature vectors into discrete features representations,preserving essential information insensitive to image quality variations.The quantized and original features are concatenated and fed into a self-attention mechanism to capture keratitis-related features.Finally,these enhanced features are classified through a fully connected layer.Experiments on clinical low-quality(LQ)images show that ADK_FVQSAM achieves accuracies of 87.7%,81.9%,and 89.3% for keratitis,other corneal abnormalities,and normal corneas,respectively.Compared to DenseNet121,Swin transformer,and InceptionResNet,ADK_FVQSAM improves average accuracy by 3.1%,11.3%,and 15.3%,respectively.These results demonstrate that ADK_FVQSAM significantly enhances the recognition performance of keratitis based on LQ slit-lamp images,offering a practical approach for clinical application.展开更多
AIM:To adapt the low vision-related quality of life(LVQOL) instrument into Turkish language and to assess its validity and reliability.METHODS:The study was conducted in 387 patients attending the Centre of Low Vision...AIM:To adapt the low vision-related quality of life(LVQOL) instrument into Turkish language and to assess its validity and reliability.METHODS:The study was conducted in 387 patients attending the Centre of Low Vision Rehabilitation,Faculty of Medicine,Ankara University.For statistical analyses,the Spearman's correlation coefficient,Cronbach's alpha coefficient and Confirmatory Factor Analysis(CFA) were used.RESULTS:According to results of CFA,the item in the 'Adjustment' subscale because of having the factor loading below 0.40,was excluded from the questionnaire.The reliability of the questionnaire was assessed according to Cronbach's alpha coefficients.The reliability of the 'Distance Vision,Mobility,and Lighting' subscale was ?琢=0.863;of the 'Adjustment' subscale was ?琢=0.694;'Reading and Fine Work' was ?琢=0.791,and 'Activities of Daily Living' was ?琢= 0.770.So these results indicate that the questionnaire is reliable to measure the vision related quality of life of low-vision patients.The correlations between the subscales were also analyzed,and the correlation between 'Adjustment' and 'Reading and Fine Work' was found to be the lowest(rs=0.336,P <0.001),whereas the strongest correlation was found between the 'Reading and Fine Work',and 'Activities of Daily Living'.Additionally,the 'Adjustment' dimension showed the strongest correlation with only 'Distance Vision,Mobility,and Lighting' dimension.CONCLUSION:After removing the last item in the second dimension,the Turkish adaptation of all dimensions of the LVQOL has been shown to be reliable,valid and suitable for use in patients with low vision in Turkey.展开更多
English is widely taught as a foreign language in China. However, the current situation of English teaching cannot keep pace with the requirements of the Senior High School Standards. The improvement of teaching quali...English is widely taught as a foreign language in China. However, the current situation of English teaching cannot keep pace with the requirements of the Senior High School Standards. The improvement of teaching quality has become the focus in the new era. This paper analyzes the situation of English teaching in Southwest China. A questionnaire-based survey indicates the typical problems, such as silent classes, lack of student-student interaction, and low quality of teacher-student interaction, which will impede the improvement of English teaching quality and hinder students to develop. The author suggests using interactive teaching in senior schools in China.展开更多
The target detection based on electroencephalogram(EEG)signals is a new target detection method.This method recognizes the target by decoding the specific neural response when an operator observes the target,which has...The target detection based on electroencephalogram(EEG)signals is a new target detection method.This method recognizes the target by decoding the specific neural response when an operator observes the target,which has important theoretical and application values.This paper focuses on the EEG detection of low-quality video targets,which breaks through the limitation of previous target detection based on EEG signals only for high-quality video targets.We first design an experimental paradigm for EEG-based low-quality video target detection and propose an epoch extraction method based on eye movement signals to solve the asynchronous problem faced by low-quality video target detection.Then,the neural representation in the process of operator recognition is analyzed based on the time domain,frequency domain,and source space domain,respectively.We design the time-frequency features based on continuous wavelet transform according to the neural representation and obtain an average decoding test accuracy of 84.56%.The research results of this paper lay the foundation for the development of a video target detection system based on EEG signals in the future.展开更多
基金Project(51208391) supported by the National Natural Science Foundation of China
文摘The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration products, quantity, pore structure and morphology were measured by X-ray diffraction(XRD), thermalgravity-differential thermal analysis(TG-DTA), mercury intrusion porosimetry(MIP) and scanning electron microscopy(SEM), respectively. The results indicate that grinding could not only improve the physical properties of the low quality fly ash on particle effect, but also improve hydration properties of the cementitious system from various aspects compared with raw low quality fly ash(RLFA). At the early stage of hydration, the low quanlity fly ash acts as almost inert material; but then at the later stage, high chemical activity, especially for ground low quality fly ash(GLFA), could be observed. It can accelerate the formation of hydration products containing more chemical bonded water, resulting in higher degree of cement hydration, thus denser microstructure and more reasonable pore size distribution, but the hydration heat in total is reduced. It can also delay the induction period, but the accelerating period is shortened and there is little influence on the second exothermic peak.
文摘To combat packet loss and realize robust video transmission over Intemet and wireless networks, a new multiple description （MD） video coding method is proposed. In the method, two descriptions for each video frame is first created by group of blocks （GOB） alternation. Motion information is then duplicated in both the descriptions and a process called low quality macroblock update is designed to redundantly encode textures in each frame using standard bit stream syntax. In this way, the output bit streams are standard compliant and better trade-offs between redundancy and single charmel reconstruction distortion are achieved. The proposed method has much better performance than the well-known MD transform coding （MDTC） method both in terms of redundancy rate distortion, and in the packet loss scenario.
基金supported by the National Natural Science Foundation of China(Nos.62276210,82201148 and 62376215)the Key Research and Development Project of Shaanxi Province(No.2025CY-YBXM-044)+3 种基金the Natural Science Foundation of Zhejiang Province(No.LQ22H120002)the Medical Health Science and Technology Project of Zhejiang Province(Nos.2022RC069 and 2023KY1140)the Natural Science Foundation of Ningbo(No.2023J390)the Ningbo Top Medical and Health Research Program(No.2023030716).
文摘This paper proposes a novel method for the automatic diagnosis of keratitis using feature vector quantization and self-attention mechanisms(ADK_FVQSAM).First,high-level features are extracted using the DenseNet121 backbone network,followed by adaptive average pooling to scale the features to a fixed length.Subsequently,product quantization with residuals(PQR)is applied to convert continuous feature vectors into discrete features representations,preserving essential information insensitive to image quality variations.The quantized and original features are concatenated and fed into a self-attention mechanism to capture keratitis-related features.Finally,these enhanced features are classified through a fully connected layer.Experiments on clinical low-quality(LQ)images show that ADK_FVQSAM achieves accuracies of 87.7%,81.9%,and 89.3% for keratitis,other corneal abnormalities,and normal corneas,respectively.Compared to DenseNet121,Swin transformer,and InceptionResNet,ADK_FVQSAM improves average accuracy by 3.1%,11.3%,and 15.3%,respectively.These results demonstrate that ADK_FVQSAM significantly enhances the recognition performance of keratitis based on LQ slit-lamp images,offering a practical approach for clinical application.
文摘AIM:To adapt the low vision-related quality of life(LVQOL) instrument into Turkish language and to assess its validity and reliability.METHODS:The study was conducted in 387 patients attending the Centre of Low Vision Rehabilitation,Faculty of Medicine,Ankara University.For statistical analyses,the Spearman's correlation coefficient,Cronbach's alpha coefficient and Confirmatory Factor Analysis(CFA) were used.RESULTS:According to results of CFA,the item in the 'Adjustment' subscale because of having the factor loading below 0.40,was excluded from the questionnaire.The reliability of the questionnaire was assessed according to Cronbach's alpha coefficients.The reliability of the 'Distance Vision,Mobility,and Lighting' subscale was ?琢=0.863;of the 'Adjustment' subscale was ?琢=0.694;'Reading and Fine Work' was ?琢=0.791,and 'Activities of Daily Living' was ?琢= 0.770.So these results indicate that the questionnaire is reliable to measure the vision related quality of life of low-vision patients.The correlations between the subscales were also analyzed,and the correlation between 'Adjustment' and 'Reading and Fine Work' was found to be the lowest(rs=0.336,P <0.001),whereas the strongest correlation was found between the 'Reading and Fine Work',and 'Activities of Daily Living'.Additionally,the 'Adjustment' dimension showed the strongest correlation with only 'Distance Vision,Mobility,and Lighting' dimension.CONCLUSION:After removing the last item in the second dimension,the Turkish adaptation of all dimensions of the LVQOL has been shown to be reliable,valid and suitable for use in patients with low vision in Turkey.
文摘English is widely taught as a foreign language in China. However, the current situation of English teaching cannot keep pace with the requirements of the Senior High School Standards. The improvement of teaching quality has become the focus in the new era. This paper analyzes the situation of English teaching in Southwest China. A questionnaire-based survey indicates the typical problems, such as silent classes, lack of student-student interaction, and low quality of teacher-student interaction, which will impede the improvement of English teaching quality and hinder students to develop. The author suggests using interactive teaching in senior schools in China.
基金supported by Basic Research Plan under Grant JCKY2022602C024.
文摘The target detection based on electroencephalogram(EEG)signals is a new target detection method.This method recognizes the target by decoding the specific neural response when an operator observes the target,which has important theoretical and application values.This paper focuses on the EEG detection of low-quality video targets,which breaks through the limitation of previous target detection based on EEG signals only for high-quality video targets.We first design an experimental paradigm for EEG-based low-quality video target detection and propose an epoch extraction method based on eye movement signals to solve the asynchronous problem faced by low-quality video target detection.Then,the neural representation in the process of operator recognition is analyzed based on the time domain,frequency domain,and source space domain,respectively.We design the time-frequency features based on continuous wavelet transform according to the neural representation and obtain an average decoding test accuracy of 84.56%.The research results of this paper lay the foundation for the development of a video target detection system based on EEG signals in the future.
