The unavoidable nature of Ulva prolifera mixed pixel in low-resolution remote sensing images would result in rough boundary of U.prolifera patches,omission of tiny patches,and overestimation of coverage area.The decom...The unavoidable nature of Ulva prolifera mixed pixel in low-resolution remote sensing images would result in rough boundary of U.prolifera patches,omission of tiny patches,and overestimation of coverage area.The decomposition of U.prolifera mixed pixel addresses the issue of coverage area overestimation,and the remaining problems can be alleviated by subpixel mapping(SPM).Due to the drift and dissipation of U.prolifera,a suitable SPM method is the single image-based unsupervised method.However,the method has difficulties in detail reconstruction,insufficient learning of spectral information,and SPM error introduced by abundance deviation.Therefore,we proposed a multiple-feature decision fusion SPM(MFDFSPM)method.It involves three branches to obtain the spatial,abundance,and spectral features of U.prolifera while considers multi-feature information using the fusion strategy.Experiments on the Geostationary Ocean Color Imager images in the Yellow Sea of China indicate that the MFDFSPM overperforms several typical U.prolifera SPM methods in higher accuracy and stronger robustness in both SPM and abundance calculation,which produced subpixel map with more detailed spatial information and less noise.展开更多
The outbreak of Ulva in the Yellow Sea has seriously affected marine ecology and economic activities.Therefore,effective prediction of the distribution of Ulva is of great significance for disaster prevention and redu...The outbreak of Ulva in the Yellow Sea has seriously affected marine ecology and economic activities.Therefore,effective prediction of the distribution of Ulva is of great significance for disaster prevention and reduction.However,the prediction method of Ulva is mainly based on numerical simulation.There are two problems with these methods.First is that the initial distribution of Ulva is simulated using independent pixel-level particles.Besides,the influence of Ulva growth and diffusion on the drift is not considered.Therefore,this paper proposes a multi-module with a two-way feedback method(MTF)to solve the above problems.The main contributions of our approach are summarized as follows.First,the initialization module,the generation and elimination module,and the drive module are composed in our way.Second,we proposed an initialization method using rectangle objects to simulate the Ulva distribution extracted from remote sensing images.Thirdly,the drift and diffusion mechanism of the Ulva is considered to realize the two-way feedback between the generation and elimination module and the drive module.The results of our experiments show that the MTF performs better than the traditional method in predicting the drift and diffusion of Ulva.The code is already publicly available at https://github.com/UPCGIT/A-multi-module-with-a-two-way-feedback-method-for-Ulva-drift-diffusion.展开更多
BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors.After resection,one of the major problems is its peritoneal dissemination and recurrence.Some free cancer cells may still exist after resection.I...BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors.After resection,one of the major problems is its peritoneal dissemination and recurrence.Some free cancer cells may still exist after resection.In addition,the surgery itself may lead to the dissemination of tumor cells.Therefore,it is necessary to remove residual tumor cells.Recently,some researchers found that extensive intraoperative peritoneal lavage(EIPL)plus intraperitoneal chemotherapy can improve the prognosis of patients and eradicate peritoneal free cancer for GC patients.However,few studies explored the safety and long-term outcome of EIPL after curative gastrectomy.AIM To evaluate the efficacy and long-term outcome of advanced GC patients treated with EIPL.METHODS According to the inclusion and exclusion criteria,a total of 150 patients with advanced GC were enrolled in this study.The patients were randomly allocated to two groups.All patients received laparotomy.For the non-EIPL group,peritoneal lavage was washed using no more than 3 L of warm saline.In the EIPL group,patients received 10 L or more of saline(1 L at a time)before the closure of the abdomen.The surviving rate analysis was compared by the Kaplan-Meier method.The prognostic factors were carried out using the Cox appropriate hazard pattern.RESULTS The basic information in the EIPL group and the non-EIPL group had no significant difference.The median follow-up time was 30 mo(range:0-45 mo).The 1-and 3-year overall survival(OS)rates were 71.0%and 26.5%,respectively.The symptoms of ileus and abdominal abscess appeared more frequently in the non-EIPL group(P<0.05).For the OS of patients,the EIPL,Borrmann classification,tumor size,N stage,T stage and vascular invasion were significant indicators.Then multivariate analysis revealed that EIPL,tumor size,vascular invasion,N stage and T stage were independent prognostic factors.The prognosis of the EIPL group was better than the non-EIPL group(P<0.001).The 3-year survival rate of the EIPL group(38.4%)was higher than the non-EIPL group(21.7%).For the recurrence-free survival(RFS)of patients,the risk factor of RFS included EIPL,N stage,vascular invasion,type of surgery,tumor location,Borrmann classification,and tumor size.EIPL and tumor size were independent risk factors.The RFS curve of the EIPL group was better than the non-EIPL group(P=0.004),and the recurrence rate of the EIPL group(24.7%)was lower than the non-EIPL group(46.4%).The overall recurrence rate and peritoneum recurrence rate in the EIPL group was lower than the non-EIPL group(P<0.05).CONCLUSION EIPL can reduce the possibility of perioperative complications including ileus and abdominal abscess.In addition,the overall survival curve and RFS curve were better in the EIPL group.展开更多
Marine oil spills are among the most significant sources of marine pollution.Synthetic aperture radar(SAR)has been used to improve oil spill observations because of its advantages in oil spill detection and identifica...Marine oil spills are among the most significant sources of marine pollution.Synthetic aperture radar(SAR)has been used to improve oil spill observations because of its advantages in oil spill detection and identification.However,speckle noise,weak boundaries,and intensity inhomogeneity often exist in the oil spill regions of SAR imagery,which will seriously aff ect the accurate identification of oil spills.To enhance marine oil spill segmentation of SAR images,a fast,edge-preserving framework based on the distance-regularized level set evolution(DRLSE)model was proposed.Specifically,a bilateral filter penalty term is designed and incorporated into the DRLSE energy function(BF-DRLSE)to preserve the edges of oil spills,and an adaptive initial box boundary was selected for the DRLSE model to reduce the operation time complexity.Two sets of RadarSat-2 SAR data were used to test the proposed method.The experimental results indicate that the bilateral filtering scheme incorporated into the energy function during level set evolution improved the stability of level set evolution.Compared with other methods,the proposed improved BF-DRLSE algorithm displayed a higher overall segmentation accuracy(97.83%).In addition,using an appropriate initial box boundary for the DRLSE method accelerated the global search process,improved the accuracy of oil spill segmentation,and reduced computational time.Therefore,the results suggest that the proposed framework is eff ective and applicable for marine oil spill segmentation.展开更多
Ocean currents are a key element in ocean processes and in meteorology,affecting material transport and modulating climate change patterns.The Doppler frequency shift information of the synthetic aperture radar(SAR)ec...Ocean currents are a key element in ocean processes and in meteorology,affecting material transport and modulating climate change patterns.The Doppler frequency shift information of the synthetic aperture radar(SAR)echo signal can reflect the dynamic characteristics of the sea surface,and has become an essential sea surface dynamic remote sensing parameter.Studies have verified that the instantaneous Doppler frequency shift can realize the SAR detection of the sea surface current.However,the validation of SAR-derived ocean current data and a thorough analysis of the errors associated with them remain lacking.In this study,we derive high spatial resolution flow measurements for the Kuroshio in the East China Sea from SAR data using a theoretical model of shifts in Doppler frequency driven by ocean surface current.Global ocean multi observation(MOB)products and global surface Lagrangian drifter(GLD)data are used to validate the Kuroshio flow retrieved from the SAR data.Results show that the central flow velocity for the Kuroshio derived from the SAR is 0.4–1.5 m/s.The error distribution between SAR ocean currents and MOB products is an approximate standard normal distribution,with the 90%confidence interval concentrated between–0.1 m/s and 0.1 m/s.Comparative analysis of SAR ocean current and GLD products,the correlation coefficient is 0.803,which shows to be significant at a confidence level of 99%.The cross-validation of different ocean current dataset illustrate that the SAR radial current captures the positions and dynamics of the Kuroshio central flow and the Kuroshio Counter Current,and has the capability to monitor current velocity over a wide range of values.展开更多
基金Supported by the Shandong Provincial Natural Science Foundation of China(No.ZR2019MD023)the National Natural Science Foundation of China(No.41776182)。
文摘The unavoidable nature of Ulva prolifera mixed pixel in low-resolution remote sensing images would result in rough boundary of U.prolifera patches,omission of tiny patches,and overestimation of coverage area.The decomposition of U.prolifera mixed pixel addresses the issue of coverage area overestimation,and the remaining problems can be alleviated by subpixel mapping(SPM).Due to the drift and dissipation of U.prolifera,a suitable SPM method is the single image-based unsupervised method.However,the method has difficulties in detail reconstruction,insufficient learning of spectral information,and SPM error introduced by abundance deviation.Therefore,we proposed a multiple-feature decision fusion SPM(MFDFSPM)method.It involves three branches to obtain the spatial,abundance,and spectral features of U.prolifera while considers multi-feature information using the fusion strategy.Experiments on the Geostationary Ocean Color Imager images in the Yellow Sea of China indicate that the MFDFSPM overperforms several typical U.prolifera SPM methods in higher accuracy and stronger robustness in both SPM and abundance calculation,which produced subpixel map with more detailed spatial information and less noise.
基金The Shandong Provincial Natural Science Foundation of China under contract No.ZR2019MD023the National Natural Science Foundation of China under contract No.41776182.
文摘The outbreak of Ulva in the Yellow Sea has seriously affected marine ecology and economic activities.Therefore,effective prediction of the distribution of Ulva is of great significance for disaster prevention and reduction.However,the prediction method of Ulva is mainly based on numerical simulation.There are two problems with these methods.First is that the initial distribution of Ulva is simulated using independent pixel-level particles.Besides,the influence of Ulva growth and diffusion on the drift is not considered.Therefore,this paper proposes a multi-module with a two-way feedback method(MTF)to solve the above problems.The main contributions of our approach are summarized as follows.First,the initialization module,the generation and elimination module,and the drive module are composed in our way.Second,we proposed an initialization method using rectangle objects to simulate the Ulva distribution extracted from remote sensing images.Thirdly,the drift and diffusion mechanism of the Ulva is considered to realize the two-way feedback between the generation and elimination module and the drive module.The results of our experiments show that the MTF performs better than the traditional method in predicting the drift and diffusion of Ulva.The code is already publicly available at https://github.com/UPCGIT/A-multi-module-with-a-two-way-feedback-method-for-Ulva-drift-diffusion.
文摘BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors.After resection,one of the major problems is its peritoneal dissemination and recurrence.Some free cancer cells may still exist after resection.In addition,the surgery itself may lead to the dissemination of tumor cells.Therefore,it is necessary to remove residual tumor cells.Recently,some researchers found that extensive intraoperative peritoneal lavage(EIPL)plus intraperitoneal chemotherapy can improve the prognosis of patients and eradicate peritoneal free cancer for GC patients.However,few studies explored the safety and long-term outcome of EIPL after curative gastrectomy.AIM To evaluate the efficacy and long-term outcome of advanced GC patients treated with EIPL.METHODS According to the inclusion and exclusion criteria,a total of 150 patients with advanced GC were enrolled in this study.The patients were randomly allocated to two groups.All patients received laparotomy.For the non-EIPL group,peritoneal lavage was washed using no more than 3 L of warm saline.In the EIPL group,patients received 10 L or more of saline(1 L at a time)before the closure of the abdomen.The surviving rate analysis was compared by the Kaplan-Meier method.The prognostic factors were carried out using the Cox appropriate hazard pattern.RESULTS The basic information in the EIPL group and the non-EIPL group had no significant difference.The median follow-up time was 30 mo(range:0-45 mo).The 1-and 3-year overall survival(OS)rates were 71.0%and 26.5%,respectively.The symptoms of ileus and abdominal abscess appeared more frequently in the non-EIPL group(P<0.05).For the OS of patients,the EIPL,Borrmann classification,tumor size,N stage,T stage and vascular invasion were significant indicators.Then multivariate analysis revealed that EIPL,tumor size,vascular invasion,N stage and T stage were independent prognostic factors.The prognosis of the EIPL group was better than the non-EIPL group(P<0.001).The 3-year survival rate of the EIPL group(38.4%)was higher than the non-EIPL group(21.7%).For the recurrence-free survival(RFS)of patients,the risk factor of RFS included EIPL,N stage,vascular invasion,type of surgery,tumor location,Borrmann classification,and tumor size.EIPL and tumor size were independent risk factors.The RFS curve of the EIPL group was better than the non-EIPL group(P=0.004),and the recurrence rate of the EIPL group(24.7%)was lower than the non-EIPL group(46.4%).The overall recurrence rate and peritoneum recurrence rate in the EIPL group was lower than the non-EIPL group(P<0.05).CONCLUSION EIPL can reduce the possibility of perioperative complications including ileus and abdominal abscess.In addition,the overall survival curve and RFS curve were better in the EIPL group.
基金Supported by the National Key R&D Program of China(No.2017YFC1405600)the National Natural Science Foundation of China(Nos.41776182,42076182)the Natural Science Foundation of Shandong Province(No.ZR2016DM16)。
文摘Marine oil spills are among the most significant sources of marine pollution.Synthetic aperture radar(SAR)has been used to improve oil spill observations because of its advantages in oil spill detection and identification.However,speckle noise,weak boundaries,and intensity inhomogeneity often exist in the oil spill regions of SAR imagery,which will seriously aff ect the accurate identification of oil spills.To enhance marine oil spill segmentation of SAR images,a fast,edge-preserving framework based on the distance-regularized level set evolution(DRLSE)model was proposed.Specifically,a bilateral filter penalty term is designed and incorporated into the DRLSE energy function(BF-DRLSE)to preserve the edges of oil spills,and an adaptive initial box boundary was selected for the DRLSE model to reduce the operation time complexity.Two sets of RadarSat-2 SAR data were used to test the proposed method.The experimental results indicate that the bilateral filtering scheme incorporated into the energy function during level set evolution improved the stability of level set evolution.Compared with other methods,the proposed improved BF-DRLSE algorithm displayed a higher overall segmentation accuracy(97.83%).In addition,using an appropriate initial box boundary for the DRLSE method accelerated the global search process,improved the accuracy of oil spill segmentation,and reduced computational time.Therefore,the results suggest that the proposed framework is eff ective and applicable for marine oil spill segmentation.
基金The National Natural Science Foundation of China under contract Nos 42176174 and 41706196the Open Research Fund of the State Key Laboratory of Estuarine and Coastal Research under contract No.SKLECKF202104+3 种基金the Zhejiang Provincial Natural Science Foundation of China under contract No.LY22D010002the National Science Foundation for Post-doctoral Scientists of China under contract No.2020M683258the Chongqing Technology Innovation and Application Development Special Project under contract No.cstc2020jscx-msxm X0193the Sichuan Science and Technology Program under contract No.2018JY0484
文摘Ocean currents are a key element in ocean processes and in meteorology,affecting material transport and modulating climate change patterns.The Doppler frequency shift information of the synthetic aperture radar(SAR)echo signal can reflect the dynamic characteristics of the sea surface,and has become an essential sea surface dynamic remote sensing parameter.Studies have verified that the instantaneous Doppler frequency shift can realize the SAR detection of the sea surface current.However,the validation of SAR-derived ocean current data and a thorough analysis of the errors associated with them remain lacking.In this study,we derive high spatial resolution flow measurements for the Kuroshio in the East China Sea from SAR data using a theoretical model of shifts in Doppler frequency driven by ocean surface current.Global ocean multi observation(MOB)products and global surface Lagrangian drifter(GLD)data are used to validate the Kuroshio flow retrieved from the SAR data.Results show that the central flow velocity for the Kuroshio derived from the SAR is 0.4–1.5 m/s.The error distribution between SAR ocean currents and MOB products is an approximate standard normal distribution,with the 90%confidence interval concentrated between–0.1 m/s and 0.1 m/s.Comparative analysis of SAR ocean current and GLD products,the correlation coefficient is 0.803,which shows to be significant at a confidence level of 99%.The cross-validation of different ocean current dataset illustrate that the SAR radial current captures the positions and dynamics of the Kuroshio central flow and the Kuroshio Counter Current,and has the capability to monitor current velocity over a wide range of values.
