Up to a quarter of polyps and adenomas are missed during colonoscopy due to poor visualization behind folds and the inner curves of flexures, and the presence of flat lesions that are difficult to detect. These number...Up to a quarter of polyps and adenomas are missed during colonoscopy due to poor visualization behind folds and the inner curves of flexures, and the presence of flat lesions that are difficult to detect. These numbers may however be conservative because they mainly come from back-to-back studies performed with standard colonoscopes, which are unable to visualize the entire mucosal surface. In the past several years, new endoscopic techniques have been introduced to improve the detection of polyps and adenomas. The introduction of high definition colonoscopes and visual image enhancement technologies have been suggested to lead to better recognition of flat and small lesions, but the absolute increase in diagnostic yield seems limited. Cap assisted colonoscopy and water-exchange colonoscopy are methods to facilitate cecal intubation and increase patients comfort, but show only a marginal or no benefit on polyp and adenoma detection. Retroflexion is routinely used in the rectum for the inspection of the dentate line, but withdrawal in retroflexion in the colon is in general not recommended due to the risk of perforation. In contrast, colonoscopy with the Third-Eye Retroscope<sup>®</sup> may result in considerable lower miss rates compared to standard colonoscopy, but this technique is not practical in case of polypectomy and is more time consuming. The recently introduced Full Spectrum Endoscopy™ colonoscopes maintains the technical capabilities of standard colonoscopes and provides a much wider view of 330 degrees compared to the 170 degrees with standard colonoscopes. Remarkable lower adenoma miss rates with this new technique were recently demonstrated in the first randomized study. Nonetheless, more studies are required to determine the exact additional diagnostic yield in clinical practice. Optimizing the efficacy of colorectal cancer screening and surveillance requires high definition colonoscopes with improved virtual chromoendoscopy technology that visualize the whole colon mucosa while maintaining optimal washing, suction and therapeutic capabilities, and keeping the procedural time as low and patient discomfort as optimal as possible.展开更多
A color based system using multiple templates was developed and implem ented for detecting human faces in color images. The algorithm consists of three image processing steps. The first step is human skin color stati...A color based system using multiple templates was developed and implem ented for detecting human faces in color images. The algorithm consists of three image processing steps. The first step is human skin color statistics. Then it separates skin regions from non-skin regions. After that, it locates the fronta l human face(s) within the skin regions. In the first step, 250 skin samples from persons of different ethnicities are used to determine the color distribution o f human skin in chromatic color space in order to get a chroma chart showing lik elihoods of skin colors. This chroma chart is used to generate, from the origina l color image, a gray scale image whose gray value at a pixel shows its likelih ood of representing the skin. The algorithm uses an adaptive thresholding proces s to achieve the optimal threshold value for dividing the gray scale image into separate skin regions from non skin regions. Finally, multiple face templates ma tching is used to determine if a given skin region represents a frontal human fa ce or not. Test of the system with more than 400 color images showed that the re sulting detection rate was 83%, which is better than most color-based face dete c tion systems. The average speed for face detection is 0.8 second/image (400×300 pixels) on a Pentium 3 (800MHz) PC.展开更多
Anomaly detection in wind turbines typically involves using normal behaviour models to detect faults early.Normal behaviour models are often implemented through the use of neural networks,of which autoencoders are par...Anomaly detection in wind turbines typically involves using normal behaviour models to detect faults early.Normal behaviour models are often implemented through the use of neural networks,of which autoencoders are particularly popular in this field.However,training autoencoder models for each turbine is time-consuming and resource intensive.Thus,transfer learning becomes essential for wind turbines with limited data or applications with limited computational resources.This study examines how cross-turbine transfer learning can be applied to autoencoder-based anomaly detection.Here,autoencoders are combined with constant thresholds for the reconstruction error to determine if input data contains an anomaly.The models are initially trained on one year’s worth of data from one or more source wind turbines.They are then fine-tuned using small amounts of data from the target wind turbine.Three methods for fine-tuning are investigated:adjusting the entire autoencoder,only the decoder,or only the threshold of the model.The performance of the transfer learning models is compared to baseline models that were trained on one year’s worth of data from the target wind turbine.The results of the tests conducted in this study indicate that models trained on data of multiple wind turbines do not improve the anomaly detection capability compared to models trained on data of one source wind turbine.In addition,modifying the model’s threshold can lead to comparable or even superior performance compared to the baseline,whereas fine-tuning the decoder or autoencoder further enhances the models’performance.展开更多
Banana bunchy top virus disease (BBTD) is a disastrous disease in bananas, and it is spreading in the world (including China) by the banana bunchy top virus(BBTV). At present, virus\|free plantlets are used to prevent...Banana bunchy top virus disease (BBTD) is a disastrous disease in bananas, and it is spreading in the world (including China) by the banana bunchy top virus(BBTV). At present, virus\|free plantlets are used to prevent BBTD in banana production, therefore, it is very important to establish a method to detect BBTV quickly, sensitively and specifically. ELISA is now popularly used to detect BBTV. The sensitivity of this method is not high enough, and needs specific antiserum, otherwise, pseudo\|positive results often occur. According to DNA coding sequences of component Ⅲ,Ⅳ and Ⅰ of BBTV isolates from Zhangzhou, China, three pairs of primers are designed to establish a PCR method to specifically amplify parts of coding sequences of the BBTV coat protein, movement protein and replicase\|association. This method is also applicable to detect BBTV of bananas or cultured banana seedlings in other regions.展开更多
Despite a decline in the overall incidence of gastric cancer(GC),the disease remains the second most common cause of cancer-related death worldwide and is thus a significant global health problem.The best means of imp...Despite a decline in the overall incidence of gastric cancer(GC),the disease remains the second most common cause of cancer-related death worldwide and is thus a significant global health problem.The best means of improving the survival of GC patients is to screen for and treat early lesions.However,GC is often diagnosed at an advanced stage and is associated with a poor prognosis.Current diagnostic and therapeutic strategies have not been successful in decreasing the global burden of the disease;therefore,the identification of reliable biomarkers for an early diagnosis,predictive markers of recurrence and survival and markers of drug sensitivity and/or resistance is urgently needed.The initiation and progression of GC depends not only on genetic alterations but also epigenetic changes,such as DNA methylation and histone modification.Aberrant DNA methylation is the most well-defined epigenetic change in human cancers and is associated with inappropriate gene silencing.Therefore,an increasing number of genes methylated at the promoter region have been targeted as possible biomarkers for different purposes,including early detection,classification,the assessment of the tumor prognosis,the development of therapeutic strategies and patient follow-up.This review article summarizes the current understanding and recent evidence regarding DNA methylation markers in GC with a focus on the clinical potential of these markers.展开更多
文摘Up to a quarter of polyps and adenomas are missed during colonoscopy due to poor visualization behind folds and the inner curves of flexures, and the presence of flat lesions that are difficult to detect. These numbers may however be conservative because they mainly come from back-to-back studies performed with standard colonoscopes, which are unable to visualize the entire mucosal surface. In the past several years, new endoscopic techniques have been introduced to improve the detection of polyps and adenomas. The introduction of high definition colonoscopes and visual image enhancement technologies have been suggested to lead to better recognition of flat and small lesions, but the absolute increase in diagnostic yield seems limited. Cap assisted colonoscopy and water-exchange colonoscopy are methods to facilitate cecal intubation and increase patients comfort, but show only a marginal or no benefit on polyp and adenoma detection. Retroflexion is routinely used in the rectum for the inspection of the dentate line, but withdrawal in retroflexion in the colon is in general not recommended due to the risk of perforation. In contrast, colonoscopy with the Third-Eye Retroscope<sup>®</sup> may result in considerable lower miss rates compared to standard colonoscopy, but this technique is not practical in case of polypectomy and is more time consuming. The recently introduced Full Spectrum Endoscopy™ colonoscopes maintains the technical capabilities of standard colonoscopes and provides a much wider view of 330 degrees compared to the 170 degrees with standard colonoscopes. Remarkable lower adenoma miss rates with this new technique were recently demonstrated in the first randomized study. Nonetheless, more studies are required to determine the exact additional diagnostic yield in clinical practice. Optimizing the efficacy of colorectal cancer screening and surveillance requires high definition colonoscopes with improved virtual chromoendoscopy technology that visualize the whole colon mucosa while maintaining optimal washing, suction and therapeutic capabilities, and keeping the procedural time as low and patient discomfort as optimal as possible.
文摘A color based system using multiple templates was developed and implem ented for detecting human faces in color images. The algorithm consists of three image processing steps. The first step is human skin color statistics. Then it separates skin regions from non-skin regions. After that, it locates the fronta l human face(s) within the skin regions. In the first step, 250 skin samples from persons of different ethnicities are used to determine the color distribution o f human skin in chromatic color space in order to get a chroma chart showing lik elihoods of skin colors. This chroma chart is used to generate, from the origina l color image, a gray scale image whose gray value at a pixel shows its likelih ood of representing the skin. The algorithm uses an adaptive thresholding proces s to achieve the optimal threshold value for dividing the gray scale image into separate skin regions from non skin regions. Finally, multiple face templates ma tching is used to determine if a given skin region represents a frontal human fa ce or not. Test of the system with more than 400 color images showed that the re sulting detection rate was 83%, which is better than most color-based face dete c tion systems. The average speed for face detection is 0.8 second/image (400×300 pixels) on a Pentium 3 (800MHz) PC.
基金funded by the German Federal Ministry for Economic Affairs and Climate Action(BMWK),Germany through the research project“ADWENTURE”(FKZ 03EE2030).
文摘Anomaly detection in wind turbines typically involves using normal behaviour models to detect faults early.Normal behaviour models are often implemented through the use of neural networks,of which autoencoders are particularly popular in this field.However,training autoencoder models for each turbine is time-consuming and resource intensive.Thus,transfer learning becomes essential for wind turbines with limited data or applications with limited computational resources.This study examines how cross-turbine transfer learning can be applied to autoencoder-based anomaly detection.Here,autoencoders are combined with constant thresholds for the reconstruction error to determine if input data contains an anomaly.The models are initially trained on one year’s worth of data from one or more source wind turbines.They are then fine-tuned using small amounts of data from the target wind turbine.Three methods for fine-tuning are investigated:adjusting the entire autoencoder,only the decoder,or only the threshold of the model.The performance of the transfer learning models is compared to baseline models that were trained on one year’s worth of data from the target wind turbine.The results of the tests conducted in this study indicate that models trained on data of multiple wind turbines do not improve the anomaly detection capability compared to models trained on data of one source wind turbine.In addition,modifying the model’s threshold can lead to comparable or even superior performance compared to the baseline,whereas fine-tuning the decoder or autoencoder further enhances the models’performance.
文摘Banana bunchy top virus disease (BBTD) is a disastrous disease in bananas, and it is spreading in the world (including China) by the banana bunchy top virus(BBTV). At present, virus\|free plantlets are used to prevent BBTD in banana production, therefore, it is very important to establish a method to detect BBTV quickly, sensitively and specifically. ELISA is now popularly used to detect BBTV. The sensitivity of this method is not high enough, and needs specific antiserum, otherwise, pseudo\|positive results often occur. According to DNA coding sequences of component Ⅲ,Ⅳ and Ⅰ of BBTV isolates from Zhangzhou, China, three pairs of primers are designed to establish a PCR method to specifically amplify parts of coding sequences of the BBTV coat protein, movement protein and replicase\|association. This method is also applicable to detect BBTV of bananas or cultured banana seedlings in other regions.
文摘Despite a decline in the overall incidence of gastric cancer(GC),the disease remains the second most common cause of cancer-related death worldwide and is thus a significant global health problem.The best means of improving the survival of GC patients is to screen for and treat early lesions.However,GC is often diagnosed at an advanced stage and is associated with a poor prognosis.Current diagnostic and therapeutic strategies have not been successful in decreasing the global burden of the disease;therefore,the identification of reliable biomarkers for an early diagnosis,predictive markers of recurrence and survival and markers of drug sensitivity and/or resistance is urgently needed.The initiation and progression of GC depends not only on genetic alterations but also epigenetic changes,such as DNA methylation and histone modification.Aberrant DNA methylation is the most well-defined epigenetic change in human cancers and is associated with inappropriate gene silencing.Therefore,an increasing number of genes methylated at the promoter region have been targeted as possible biomarkers for different purposes,including early detection,classification,the assessment of the tumor prognosis,the development of therapeutic strategies and patient follow-up.This review article summarizes the current understanding and recent evidence regarding DNA methylation markers in GC with a focus on the clinical potential of these markers.
