The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of...The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape fimction. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed.展开更多
A weak nonlinear model of a two-layer barotropic ocean with Rayleigh dissipation is built.The analytic asymptotic solution is derived in the mid-latitude stationary wind field,and the physical meaning of the correspon...A weak nonlinear model of a two-layer barotropic ocean with Rayleigh dissipation is built.The analytic asymptotic solution is derived in the mid-latitude stationary wind field,and the physical meaning of the corresponding problem is discussed.展开更多
Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered so...Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered soils remains a complex challenge.This study presents a novel application of five ensemble machine(ML)algorithms-random forest(RF),gradient boosting machine(GBM),extreme gradient boosting(XGBoost),adaptive boosting(AdaBoost),and categorical boosting(CatBoost)-to predict the undrained bearing capacity factor(Nc)of circular open caissons embedded in two-layered clay on the basis of results from finite element limit analysis(FELA).The input dataset consists of 1188 numerical simulations using the Tresca failure criterion,varying in geometrical and soil parameters.The FELA was performed via OptumG2 software with adaptive meshing techniques and verified against existing benchmark studies.The ML models were trained on 70% of the dataset and tested on the remaining 30%.Their performance was evaluated using six statistical metrics:coefficient of determination(R²),mean absolute error(MAE),root mean squared error(RMSE),index of scatter(IOS),RMSE-to-standard deviation ratio(RSR),and variance explained factor(VAF).The results indicate that all the models achieved high accuracy,with R²values exceeding 97.6%and RMSE values below 0.02.Among them,AdaBoost and CatBoost consistently outperformed the other methods across both the training and testing datasets,demonstrating superior generalizability and robustness.The proposed ML framework offers an efficient,accurate,and data-driven alternative to traditional methods for estimating caisson capacity in stratified soils.This approach can aid in reducing computational costs while improving reliability in the early stages of foundation design.展开更多
This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerge...This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerged cylindrical buoy.The system is modeled as a two-layer fluid with infinite horizontal extent and finite depth.The radiation problem is analyzed in the context of linear water waves.The fluid domain is divided into outer and inner zones,and mathematical solutions for the pitch radiating potential are derived for the corresponding boundary valve problem in these zones using the separation of variables approach.Using the matching eigenfunction expansion method,the unknown coefficients in the analytical expression of the radiation potentials are evaluated.The resulting radiation potential is then used to compute the added mass and damping coefficients.Several numerical results for the added mass and damping coefficients are investigated for numerous parameters,particularly the effects of the cylinder radius,the draft of the submerged cylinder,and the density proportion between the two fluid layers across different frequency ranges.The major findings are presented and discussed.展开更多
A two-layer primitive equation model is developed in this paper. The capabilities of this model aretested by the use of multiyearly averaged January and July sea surface level pressure fields and windfields which can ...A two-layer primitive equation model is developed in this paper. The capabilities of this model aretested by the use of multiyearly averaged January and July sea surface level pressure fields and windfields which can be diagnosed from the pressure fields. The results show that the ocean surface currentsand undercurrents in the second layer driven by the sea surface wind and the sea surface pressure areclose to the observation. The results are also compared with that of the IAP OGCM and the OSUOGCM.展开更多
Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class at...Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class attacks,this study proposes an intrusion detection method based on a two-layer structure.The first layer employs a CNN-BiLSTM model incorporating an attention mechanism to classify network traffic into normal traffic,majority class attacks,and merged minority class attacks.The second layer further segments the minority class attacks through Stacking ensemble learning.The datasets are selected from the generic network dataset CIC-IDS2017,NSL-KDD,and the industrial network dataset Mississippi Gas Pipeline dataset to enhance the generalization and practical applicability of the model.Experimental results show that the proposed model achieves an overall detection accuracy of 99%,99%,and 95%on the CIC-IDS2017,NSL-KDD,and industrial network datasets,respectively.It also significantly outperforms traditional methods in terms of detection accuracy and recall rate for minority class attacks.Compared with the single-layer deep learning model,the two-layer structure effectively reduces the false alarm rate while improving the minority-class attack detection performance.The research in this paper not only improves the adaptability of NIDS to complex network environments but also provides a new solution for minority-class attack detection in industrial network security.展开更多
BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To ...BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To develop an interpretable noninvasive early diagnostic model for PDAC using plasma extracellular vesicle long RNA(EvlRNA).METHODS The diagnostic model was constructed based on plasma EvlRNA data.During the process of establishing the model,EvlRNA-index was introduced,and four algorithms were adopted to calculate EvlRNA-index.After the model was successfully constructed,performance evaluation was conducted.A series of bioinformatics methods were adopted to explore the potential mechanism of EvlRNA-index as the input feature of the model.And the relationship between key characteristics and PDAC were explored at the single-cell level.RESULTS A novel interpretable machine learning framework was developed based on plasma EvlRNA.In this framework,a two-layer classifier was established.A new concept was proposed:EvlRNA-index.Based on EvlRNA-index,a cancer diagnostic model was established,and a good diagnostic effect was achieved.The accuracy of PDACandCPvsHealth-Probabilistic PCA Index-SVM(PDAC and chronic pancreatitis vs health-probabilistic principal component analysis index-support vector machine)(1-18)was 91.51%,with Mathew’s correlation coefficient 0.7760 and area under the curve 0.9560.In the second layer of the model,the accuracy of PDACvsCP-Probabilistic PCA Index-RF(PDAC vs chronic pancreatitis-probabilistic principal component analysis index-random forest)(2-17)was 93.83%,with Mathew’s correlation coefficient 0.8422 and area under the curve 0.9698.Forty-nine PDAC-related genes were identified,among which 16 were known,inferring that the remaining ones were also PDAC-related genes.CONCLUSION An interpretable two-layer machine learning framework was proposed for early diagnosis and prediction of PDAC based on plasma EvlRNA,providing new insights into the clinical value of EvlRNA.展开更多
In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapi...In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapid deployment and high mobil-ity,are commonly regarded as an ideal option for con-structing temporary communication networks.Con-sidering the limited computing capability and battery power of UAVs,this paper proposes a two-layer UAV cooperative computing offloading strategy for emer-gency disaster relief scenarios.The multi-agent twin delayed deep deterministic policy gradient(MATD3)algorithm integrated with prioritized experience replay(PER)is utilized to jointly optimize the scheduling strategies of UAVs,task offloading ratios,and their mobility,aiming to diminish the energy consumption and delay of the system to the minimum.In order to address the aforementioned non-convex optimiza-tion issue,a Markov decision process(MDP)has been established.The results of simulation experiments demonstrate that,compared with the other four base-line algorithms,the algorithm introduced in this paper exhibits better convergence performance,verifying its feasibility and efficacy.展开更多
On July 2^(nd),2025,32 scientists representing 15 countries gathered at Tartu,Estonia to make on-site endorsements for the Global ONCE(Ocean Negative Carbon Emissions)Program at the 12th INTECOL Wetlands Conference.Th...On July 2^(nd),2025,32 scientists representing 15 countries gathered at Tartu,Estonia to make on-site endorsements for the Global ONCE(Ocean Negative Carbon Emissions)Program at the 12th INTECOL Wetlands Conference.This marks a significant milestone for ONCE in establishing a systematic framework for coastal wetland carbon sequestration research and global collaboration(Figs.1,2).Coastal wetlands are critical transition zones linking terrestrial and marine ecosystems,yet they face severe degradation from anthropogenic land-based activities and sea level rise that propagate impacts to the ocean.As a UN Ocean Decade Program,the Global ONCE Program champions interdisciplinary and cross-regional collaboration to enhance carbon sequestration in the ocean and coastal wetlands through science and innovation.Aligned with the Tartu Declaration on Wetlands that includes resolutions to promote the rights of global wetlands(especially peatlands)and advance the discipline of wetland science based on facts,this initiative addresses key knowledge gaps in land-ocean interactions.The goal is to harness the full potential of coastal wetlands and ocean systems for climate mitigation,thereby laying a scientific foundation for international policy formulation and implementation.展开更多
The IUGG Associations for Atmosphere,Oceans and Cryosphere—IAMAS,IAPSO and IACS—held a Joint Scientific Assembly in Busan,South Korea,from 20 to 25 July 2025.This was the first joint assembly of all three associatio...The IUGG Associations for Atmosphere,Oceans and Cryosphere—IAMAS,IAPSO and IACS—held a Joint Scientific Assembly in Busan,South Korea,from 20 to 25 July 2025.This was the first joint assembly of all three associations since 2009,when they met in Montreal,Canada.It was the first time any of the associations had been hosted in Korea,and it had been two decades since any of them had met in Asia.The choice of Busan as the venue supported high levels of participation and smooth conference operations.The Local Organizing Committee,chaired by Prof.Kyung-Ja Ha of Pusan National University,oversaw the successful organization of the event.The assembly brought together 1725 participants in total,including 1282 researchers and 443 invited participants and individuals involved in side events,exhibitions,media coverage,and volunteer work.Participants came from 46 countries across Asia,Europe,North America,South America,Africa,and Oceania.IAMAS had 736 participants,IAPSO 321,and IACS 225.Survey data from 951 respondents revealed that Early Career Scientists,defined as those within 10 years of receiving their PhD,accounted for approximately 25%of participants.The demographic profile skewed young,with 66%of attendees in their 20s and 30s.The scientific program was organized by Prof.Seon-Ki Park(Chair),the Secretaries General from all three Associations,and the Local Organizing Committee.Reflecting the theme“Our Interconnected Earth,”the scientific program emphasized integrated approaches to climate systems,addressing climate change and environmental challenges through collaborative,transdisciplinary research.展开更多
This study investigates the vertical variations of aerosol size distribution (0.06–1µm) and cloud condensation nuclei(CCN) spectra over the Southern Ocean (SO) using aircraft observations from the SOCRATES campa...This study investigates the vertical variations of aerosol size distribution (0.06–1µm) and cloud condensation nuclei(CCN) spectra over the Southern Ocean (SO) using aircraft observations from the SOCRATES campaign.Results reveal a bimodal aerosol size distribution within the marine boundary layer (MBL),with peaks at diameters of~0.06µm and~0.65µm,dominated by sea-salt particles.Accumulation-mode aerosol concentrations decrease with altitude within the MBL,while Aitken-mode aerosol concentrations peak above the MBL (~2–3 km).Wind speed strongly correlates with coarse-mode aerosol concentration (R2=0.77),implicating sea spray as a major CCN source at low supersaturations (SS=0.1%).The altitudes of CCN concentration peaks shift from the MBL (<1 km,SS<0.4%) to the free troposphere (~2.5 km,SS>0.4%),suggesting new particle formation aloft,distinct from sea surface sources.These findings highlight the unique aerosol–CCN dynamics in the pristine SO,offering critical constraints for models simulating cloud–aerosol interactions in preindustrial-like environments.展开更多
The eddies in the southernmost southern Indian Ocean exert major dynamical and biogeochemical influences on the Earth system.Therefore,disentangling the relative contributions of vertical pumping and horizontal transp...The eddies in the southernmost southern Indian Ocean exert major dynamical and biogeochemical influences on the Earth system.Therefore,disentangling the relative contributions of vertical pumping and horizontal transport to water-property anomalies in the eddy cores is of fundamental importance.Here,the authors introduce a temperaturesalinity gradient-ratio approach(the"R-method")that compares vertical and meridional gradients to quantitatively separate the two processes.Application of the R-method to three-dimensional Argo observations reveals that horizontal transport,rather than vertical pumping,predominantly governs the observed temperature and salinity anomalies within eddy cores in the SIO.Independent theoretical estimations based on background meridional gradients,together with composites formed on isopycnal surfaces,further corroborate this conclusion.The results challenge the conventional assumption that vertical pumping invariably controls eddy-core property anomalies and demonstrate the utility of the R-method for diagnosing eddy impacts in climate and biogeochemical studies.展开更多
Prydz Bay,East Antarctica,is a critical region for studying ocean–sea ice–ice shelf interactions and their role in the global climate system.This review synthesizes the advancements in numerical modeling of physical...Prydz Bay,East Antarctica,is a critical region for studying ocean–sea ice–ice shelf interactions and their role in the global climate system.This review synthesizes the advancements in numerical modeling of physical oceanographic processes in Prydz Bay,highlighting the evolution from early one-dimensional thermodynamic models to contemporary high-resolution,three-dimensional coupled ocean–sea ice–ice shelf frameworks.We discuss key milestones in understanding processes such as frazil ice dynamics and its impact on the basal mass balance of the Amery Ice Shelf,the pathways and mechanisms of Modified Circumpolar Deep Water intrusions,and the dynamic influences of large icebergs on regional circulation.Despite significant progress,challenges remain in integrating multi-component interactions and achieving long-term,high-resolution climate projections.Future efforts should focus on developing fully coupled models that incorporate atmosphere–ocean–sea ice–ice shelf–iceberg interactions,supported by enhanced observational networks and improved computational efficiency.This review underscores the importance of continued modeling advancement to better predict the responses of Antarctic ice shelves and polar climate to global change.展开更多
The present study compares the Atlantic Meridional Overturning Circulation(AMOC)in the North Atlantic from two simulations by an oceanic general circulation model with 1°×1°and 0.1°×0.1°r...The present study compares the Atlantic Meridional Overturning Circulation(AMOC)in the North Atlantic from two simulations by an oceanic general circulation model with 1°×1°and 0.1°×0.1°resolution,respectively,which explores the sensitivity of AMOC to the resolution.The ocean model is the latest version of the LASG/IAP Climate System Model(LICOM3),and it is forced with atmospheric data from phase 2 of the Ocean Model Intercomparison Project(OMIP2).Comprehensive comparison between the two simulations indicates that the simulated AMOC is highly sensitive to the spatial resolution.The high-resolution model(LICOM-H)simulates a deeper mixed-layer depth(MLD),due to increased surface salinity,than that in the low-resolution model(LICOML)in the Labrador Sea,and it also has stronger AMOC strength(the maximum climatic mean AMOC from 1958 to 2018 is 23.4 Sv for LICOM-H and 21.2 Sv for LICOM-L)and larger variability of AMOC index(2.3 Sv for LICOM-H and 1.7 Sv for LICOM-L).These differences can mainly be attributed to two main dynamic processes that benefit from high resolution.Firstly,LICOM-H can simulate much stronger boundary currents(~0.6 m s^(-1))than LICOM-L(0.3 m s^(-1))in the upper ocean,which leads to saltier and warmer seawater being transported to the Labrador Sea,where it enhances deep convection.Secondly,in LICOM-H,the stronger variability of AMOC is related to the higher sensitivity of the MLD and transformation to the prescribed atmospheric forcing in the Labrador Sea.展开更多
Atmospheric carbon dioxide(CO_(2))levels are escalating at an unprecedented rate,leading to the phenomenon of ocean acidification(OA).Parental exposure to acidification has the potential to enhance offspring resilienc...Atmospheric carbon dioxide(CO_(2))levels are escalating at an unprecedented rate,leading to the phenomenon of ocean acidification(OA).Parental exposure to acidification has the potential to enhance offspring resilience through cross-generation plasticity.In this study,we analyzed larval growth and transcriptomic profiles in the Pacific oyster,Crassostrea gigas,a species of significant ecological relevance,under both control and elevated CO_(2)conditions experienced by their parental generation.Our findings indicate that the oyster populations exposed to OA exhibited a higher incidence of abnormalities during the D-shaped larval stage,followed by accelerated growth at the eyed stage.Through a comparative transcriptomic investigation of eyed larvae(25 d after fertilization),we observed that parental exposure to OA substantially influenced the gene expression in the offspring.Genes associated with lipid catabolism and shell formation were notably upregulated in oysters with parental OA exposure,potentially playing a role in cross-generational conditioning and conferring resilience to OA stressors.These results underscore the profound impact of OA on oyster larval development via cross-generational mechanisms and shed light on the molecular underpinnings of cross-generation plasticity.展开更多
This research evaluates the performance of an eddy-resolving forecast system(LFS)in simulating mesoscale eddies over the South China Sea(SCs)through a comparative analysis with satellite observations and the reanalysi...This research evaluates the performance of an eddy-resolving forecast system(LFS)in simulating mesoscale eddies over the South China Sea(SCs)through a comparative analysis with satellite observations and the reanalysis dataset from the Global Ocean Physics Reanalysis product(CMEMS).The findings indicate that the spatial characteristics of eddy kinetic energy,number,and amplitude of coherent mesoscale eddies simulated by LFS exhibit a reasonable agreement with satellite observations.The reproduced seasonal variations are also comparable to outputs from the CMEMS reanalysis dataset.Nevertheless,certain systematic biases have also been identified.In the SCS,LFS generates approximately 17%fewer eddies than observed.Such biases are also evident in the CMEMS reanalysis dataset.Similar to the statistics shown in the CMEMS reanalysis dataset,both cyclonic and anticyclonic eddies are significantly weaker in LFS compared to the observations.Additionally,the composite three-dimensional structures of mesoscale eddies simulated by LFS exhibit a remarkable similarity to those identified in the CMEMS reanalysis datasets.This work lays the foundation for further studies using LFS to investigate the predictability of mesoscale eddies and enhance the accuracy of simulations.展开更多
The Yellow Sea and Bohai Sea are among the global shelf seas susceptible to typhoons every year.Using observations and high-resolution numerical simulations,the current study investigates the dramatic changes in tempe...The Yellow Sea and Bohai Sea are among the global shelf seas susceptible to typhoons every year.Using observations and high-resolution numerical simulations,the current study investigates the dramatic changes in temperature and ocean heat content(OHC)of the Yellow Sea and Bohai Sea caused by Super Typhoon Maysak in early September 2020,which is representative of northward/northeastward-bypassing typhoons with centers just to the east of the study area.Temperature shows spatially coherent cooling in the upper mixed layer but warming in the subsurface layer in the majority of the offshore waters,due to wind-enhanced vertical mixing.In lower layers from the thermocline to sea bottom,temperature experiences significant warming in northeastern coastal waters of the Shandong Peninsula and in regions just off the Subei Shoal,but significant cooling in western coastal waters of the Korean Peninsula and southern coastal waters of the Shandong Peninsula.Significant temperature warming/cooling in lower layers is caused by coastal downwelling/upwelling.The total OHC of the study area decreases rapidly during Typhoon Maysak(2020)’s passage,which is generated comparably by latent heat loss at the sea surface and southward heat advection out of the study area at the southern boundary.Reduced shortwave radiation contributes positively but secondarily to the decreasing OHC during the first day.A numerical experiment suggests that Typhoon Maysak(2020)-induced OHC decline could have greatly affected the regional climate evolution in the following seasons.More studies are needed to fully understand the impacts of typhoons on regional climate changes in shelf seas at different time scales.展开更多
Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(EN...Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(ENSO)on summer precipitation in China.The inverse phase spatial distribution of sea surface temperature anomalies(SSTAs)in the southwest and northeast of the southern Indian Ocean is defined as the SIOD.Positive SIOD events(positive SSTAs in the southwest,negative SSTAs in the northeast)are associated with La Niña events(Central Pacific(CP)type),while negative SIOD events(negative SSTAs in the southwest,positive SSTAs in the northeast)are associated with El Niño events(Eastern Pacific(EP)type).Both SIOD and ENSO have certain impacts on summer precipitation in China.Precipitation in the Yangtze River basin decreases,while precipitation in southern China increases during pure positive SIOD(P_PSIOD)events.During pure negative SIOD(P_NSIOD)events,the changes in precipitation are exactly the opposite of those during P_PSIOD events,which may be due to differences in the cross-equatorial flow in the southern Indian Ocean,particularly in low-level Australian cross-equatorial flow.When positive SIOD and CP-type La Niña events occur simultaneously(PSIOD+La_Niña),precipitation increases in the Yangtze-Huaihe River basin,while it decreases in northern China.When negative SIOD and EP-type El Niño events occur simultaneously(NSIOD+El_Niño),precipitation in the Yangtze-Huaihe River basin is significantly lower than during P_NSIOD events.This is caused by differences in water vapor originating from the Pacific Ocean during different events.展开更多
文摘The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape fimction. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB403501)the National Natural Science Foundation of China (GrantNos. 41175058,41275062,and 11202106)
文摘A weak nonlinear model of a two-layer barotropic ocean with Rayleigh dissipation is built.The analytic asymptotic solution is derived in the mid-latitude stationary wind field,and the physical meaning of the corresponding problem is discussed.
文摘Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered soils remains a complex challenge.This study presents a novel application of five ensemble machine(ML)algorithms-random forest(RF),gradient boosting machine(GBM),extreme gradient boosting(XGBoost),adaptive boosting(AdaBoost),and categorical boosting(CatBoost)-to predict the undrained bearing capacity factor(Nc)of circular open caissons embedded in two-layered clay on the basis of results from finite element limit analysis(FELA).The input dataset consists of 1188 numerical simulations using the Tresca failure criterion,varying in geometrical and soil parameters.The FELA was performed via OptumG2 software with adaptive meshing techniques and verified against existing benchmark studies.The ML models were trained on 70% of the dataset and tested on the remaining 30%.Their performance was evaluated using six statistical metrics:coefficient of determination(R²),mean absolute error(MAE),root mean squared error(RMSE),index of scatter(IOS),RMSE-to-standard deviation ratio(RSR),and variance explained factor(VAF).The results indicate that all the models achieved high accuracy,with R²values exceeding 97.6%and RMSE values below 0.02.Among them,AdaBoost and CatBoost consistently outperformed the other methods across both the training and testing datasets,demonstrating superior generalizability and robustness.The proposed ML framework offers an efficient,accurate,and data-driven alternative to traditional methods for estimating caisson capacity in stratified soils.This approach can aid in reducing computational costs while improving reliability in the early stages of foundation design.
基金supported by MHRD as researcher C.K.Neog received the MHRD Institute GATE scholarship from Govt.of India.
文摘This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerged cylindrical buoy.The system is modeled as a two-layer fluid with infinite horizontal extent and finite depth.The radiation problem is analyzed in the context of linear water waves.The fluid domain is divided into outer and inner zones,and mathematical solutions for the pitch radiating potential are derived for the corresponding boundary valve problem in these zones using the separation of variables approach.Using the matching eigenfunction expansion method,the unknown coefficients in the analytical expression of the radiation potentials are evaluated.The resulting radiation potential is then used to compute the added mass and damping coefficients.Several numerical results for the added mass and damping coefficients are investigated for numerous parameters,particularly the effects of the cylinder radius,the draft of the submerged cylinder,and the density proportion between the two fluid layers across different frequency ranges.The major findings are presented and discussed.
文摘A two-layer primitive equation model is developed in this paper. The capabilities of this model aretested by the use of multiyearly averaged January and July sea surface level pressure fields and windfields which can be diagnosed from the pressure fields. The results show that the ocean surface currentsand undercurrents in the second layer driven by the sea surface wind and the sea surface pressure areclose to the observation. The results are also compared with that of the IAP OGCM and the OSUOGCM.
基金supported by the Institute of Information&Communications Technology Planning&Evaluation(IITP)—Innovative Human Resource Development for Local Intellectualization program grant funded by the Korea government(MSIT)(IITP-2025-RS-2022-00156334)in part by Liaoning Province Nature Fund Project(2024-BSLH-214).
文摘Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class attacks,this study proposes an intrusion detection method based on a two-layer structure.The first layer employs a CNN-BiLSTM model incorporating an attention mechanism to classify network traffic into normal traffic,majority class attacks,and merged minority class attacks.The second layer further segments the minority class attacks through Stacking ensemble learning.The datasets are selected from the generic network dataset CIC-IDS2017,NSL-KDD,and the industrial network dataset Mississippi Gas Pipeline dataset to enhance the generalization and practical applicability of the model.Experimental results show that the proposed model achieves an overall detection accuracy of 99%,99%,and 95%on the CIC-IDS2017,NSL-KDD,and industrial network datasets,respectively.It also significantly outperforms traditional methods in terms of detection accuracy and recall rate for minority class attacks.Compared with the single-layer deep learning model,the two-layer structure effectively reduces the false alarm rate while improving the minority-class attack detection performance.The research in this paper not only improves the adaptability of NIDS to complex network environments but also provides a new solution for minority-class attack detection in industrial network security.
基金Supported by Talent Scientific Research Start-up Foundation of Wannan Medical College,No.WYRCQD2023045.
文摘BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To develop an interpretable noninvasive early diagnostic model for PDAC using plasma extracellular vesicle long RNA(EvlRNA).METHODS The diagnostic model was constructed based on plasma EvlRNA data.During the process of establishing the model,EvlRNA-index was introduced,and four algorithms were adopted to calculate EvlRNA-index.After the model was successfully constructed,performance evaluation was conducted.A series of bioinformatics methods were adopted to explore the potential mechanism of EvlRNA-index as the input feature of the model.And the relationship between key characteristics and PDAC were explored at the single-cell level.RESULTS A novel interpretable machine learning framework was developed based on plasma EvlRNA.In this framework,a two-layer classifier was established.A new concept was proposed:EvlRNA-index.Based on EvlRNA-index,a cancer diagnostic model was established,and a good diagnostic effect was achieved.The accuracy of PDACandCPvsHealth-Probabilistic PCA Index-SVM(PDAC and chronic pancreatitis vs health-probabilistic principal component analysis index-support vector machine)(1-18)was 91.51%,with Mathew’s correlation coefficient 0.7760 and area under the curve 0.9560.In the second layer of the model,the accuracy of PDACvsCP-Probabilistic PCA Index-RF(PDAC vs chronic pancreatitis-probabilistic principal component analysis index-random forest)(2-17)was 93.83%,with Mathew’s correlation coefficient 0.8422 and area under the curve 0.9698.Forty-nine PDAC-related genes were identified,among which 16 were known,inferring that the remaining ones were also PDAC-related genes.CONCLUSION An interpretable two-layer machine learning framework was proposed for early diagnosis and prediction of PDAC based on plasma EvlRNA,providing new insights into the clinical value of EvlRNA.
基金supported by the Basic Scientific Research Business Fund Project of Higher Education Institutions in Heilongjiang Province(145409601)the First Batch of Experimental Teaching and Teaching Laboratory Construction Research Projects in Heilongjiang Province(SJGZ20240038).
文摘In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapid deployment and high mobil-ity,are commonly regarded as an ideal option for con-structing temporary communication networks.Con-sidering the limited computing capability and battery power of UAVs,this paper proposes a two-layer UAV cooperative computing offloading strategy for emer-gency disaster relief scenarios.The multi-agent twin delayed deep deterministic policy gradient(MATD3)algorithm integrated with prioritized experience replay(PER)is utilized to jointly optimize the scheduling strategies of UAVs,task offloading ratios,and their mobility,aiming to diminish the energy consumption and delay of the system to the minimum.In order to address the aforementioned non-convex optimiza-tion issue,a Markov decision process(MDP)has been established.The results of simulation experiments demonstrate that,compared with the other four base-line algorithms,the algorithm introduced in this paper exhibits better convergence performance,verifying its feasibility and efficacy.
文摘On July 2^(nd),2025,32 scientists representing 15 countries gathered at Tartu,Estonia to make on-site endorsements for the Global ONCE(Ocean Negative Carbon Emissions)Program at the 12th INTECOL Wetlands Conference.This marks a significant milestone for ONCE in establishing a systematic framework for coastal wetland carbon sequestration research and global collaboration(Figs.1,2).Coastal wetlands are critical transition zones linking terrestrial and marine ecosystems,yet they face severe degradation from anthropogenic land-based activities and sea level rise that propagate impacts to the ocean.As a UN Ocean Decade Program,the Global ONCE Program champions interdisciplinary and cross-regional collaboration to enhance carbon sequestration in the ocean and coastal wetlands through science and innovation.Aligned with the Tartu Declaration on Wetlands that includes resolutions to promote the rights of global wetlands(especially peatlands)and advance the discipline of wetland science based on facts,this initiative addresses key knowledge gaps in land-ocean interactions.The goal is to harness the full potential of coastal wetlands and ocean systems for climate mitigation,thereby laying a scientific foundation for international policy formulation and implementation.
基金support from USA NSF(Grant No.OPP2213875)NASA(Grant No.80NSSC22K1707).
文摘The IUGG Associations for Atmosphere,Oceans and Cryosphere—IAMAS,IAPSO and IACS—held a Joint Scientific Assembly in Busan,South Korea,from 20 to 25 July 2025.This was the first joint assembly of all three associations since 2009,when they met in Montreal,Canada.It was the first time any of the associations had been hosted in Korea,and it had been two decades since any of them had met in Asia.The choice of Busan as the venue supported high levels of participation and smooth conference operations.The Local Organizing Committee,chaired by Prof.Kyung-Ja Ha of Pusan National University,oversaw the successful organization of the event.The assembly brought together 1725 participants in total,including 1282 researchers and 443 invited participants and individuals involved in side events,exhibitions,media coverage,and volunteer work.Participants came from 46 countries across Asia,Europe,North America,South America,Africa,and Oceania.IAMAS had 736 participants,IAPSO 321,and IACS 225.Survey data from 951 respondents revealed that Early Career Scientists,defined as those within 10 years of receiving their PhD,accounted for approximately 25%of participants.The demographic profile skewed young,with 66%of attendees in their 20s and 30s.The scientific program was organized by Prof.Seon-Ki Park(Chair),the Secretaries General from all three Associations,and the Local Organizing Committee.Reflecting the theme“Our Interconnected Earth,”the scientific program emphasized integrated approaches to climate systems,addressing climate change and environmental challenges through collaborative,transdisciplinary research.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.42430601,42175087)the Science and Technology Project of Gansu Province(Outstanding Youth Fund,Grant No.24JRRA386)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2024-jdzx04)。
文摘This study investigates the vertical variations of aerosol size distribution (0.06–1µm) and cloud condensation nuclei(CCN) spectra over the Southern Ocean (SO) using aircraft observations from the SOCRATES campaign.Results reveal a bimodal aerosol size distribution within the marine boundary layer (MBL),with peaks at diameters of~0.06µm and~0.65µm,dominated by sea-salt particles.Accumulation-mode aerosol concentrations decrease with altitude within the MBL,while Aitken-mode aerosol concentrations peak above the MBL (~2–3 km).Wind speed strongly correlates with coarse-mode aerosol concentration (R2=0.77),implicating sea spray as a major CCN source at low supersaturations (SS=0.1%).The altitudes of CCN concentration peaks shift from the MBL (<1 km,SS<0.4%) to the free troposphere (~2.5 km,SS>0.4%),suggesting new particle formation aloft,distinct from sea surface sources.These findings highlight the unique aerosol–CCN dynamics in the pristine SO,offering critical constraints for models simulating cloud–aerosol interactions in preindustrial-like environments.
基金supported by the National Natural Science Foundation of China [grant number 42176001]the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences [grant number LTO2106]the STU Scientific Research Foundation for Talents [grant number NTF21009]。
文摘The eddies in the southernmost southern Indian Ocean exert major dynamical and biogeochemical influences on the Earth system.Therefore,disentangling the relative contributions of vertical pumping and horizontal transport to water-property anomalies in the eddy cores is of fundamental importance.Here,the authors introduce a temperaturesalinity gradient-ratio approach(the"R-method")that compares vertical and meridional gradients to quantitatively separate the two processes.Application of the R-method to three-dimensional Argo observations reveals that horizontal transport,rather than vertical pumping,predominantly governs the observed temperature and salinity anomalies within eddy cores in the SIO.Independent theoretical estimations based on background meridional gradients,together with composites formed on isopycnal surfaces,further corroborate this conclusion.The results challenge the conventional assumption that vertical pumping invariably controls eddy-core property anomalies and demonstrate the utility of the R-method for diagnosing eddy impacts in climate and biogeochemical studies.
基金supported by the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant nos.SML2021SP306,SML2023SP201)the National Key R&D Program of China(Grant no.2024YFF0506603)+1 种基金the National Natural Science Foundation of China(Grant no.42576020)Guangdong Basic and Applied Basic Research Foundation,China(Grant nos.2024A1515012717,2026A1515012241).
文摘Prydz Bay,East Antarctica,is a critical region for studying ocean–sea ice–ice shelf interactions and their role in the global climate system.This review synthesizes the advancements in numerical modeling of physical oceanographic processes in Prydz Bay,highlighting the evolution from early one-dimensional thermodynamic models to contemporary high-resolution,three-dimensional coupled ocean–sea ice–ice shelf frameworks.We discuss key milestones in understanding processes such as frazil ice dynamics and its impact on the basal mass balance of the Amery Ice Shelf,the pathways and mechanisms of Modified Circumpolar Deep Water intrusions,and the dynamic influences of large icebergs on regional circulation.Despite significant progress,challenges remain in integrating multi-component interactions and achieving long-term,high-resolution climate projections.Future efforts should focus on developing fully coupled models that incorporate atmosphere–ocean–sea ice–ice shelf–iceberg interactions,supported by enhanced observational networks and improved computational efficiency.This review underscores the importance of continued modeling advancement to better predict the responses of Antarctic ice shelves and polar climate to global change.
基金supported by the National Natural Science Foundation of China [grant number 92358302]。
文摘The present study compares the Atlantic Meridional Overturning Circulation(AMOC)in the North Atlantic from two simulations by an oceanic general circulation model with 1°×1°and 0.1°×0.1°resolution,respectively,which explores the sensitivity of AMOC to the resolution.The ocean model is the latest version of the LASG/IAP Climate System Model(LICOM3),and it is forced with atmospheric data from phase 2 of the Ocean Model Intercomparison Project(OMIP2).Comprehensive comparison between the two simulations indicates that the simulated AMOC is highly sensitive to the spatial resolution.The high-resolution model(LICOM-H)simulates a deeper mixed-layer depth(MLD),due to increased surface salinity,than that in the low-resolution model(LICOML)in the Labrador Sea,and it also has stronger AMOC strength(the maximum climatic mean AMOC from 1958 to 2018 is 23.4 Sv for LICOM-H and 21.2 Sv for LICOM-L)and larger variability of AMOC index(2.3 Sv for LICOM-H and 1.7 Sv for LICOM-L).These differences can mainly be attributed to two main dynamic processes that benefit from high resolution.Firstly,LICOM-H can simulate much stronger boundary currents(~0.6 m s^(-1))than LICOM-L(0.3 m s^(-1))in the upper ocean,which leads to saltier and warmer seawater being transported to the Labrador Sea,where it enhances deep convection.Secondly,in LICOM-H,the stronger variability of AMOC is related to the higher sensitivity of the MLD and transformation to the prescribed atmospheric forcing in the Labrador Sea.
基金Supported by the Key Research and Development Program of Shandong(No.2022LZGC015)the National Key R&D Program of China(No.2022YFD2401400)+1 种基金the Taishan Scholars Program,the National Key R&D Program of China(No.2022YFD2400304)the Agricultural Seed Project of Shandong Key R&D Program(No.2024LZGCQY003)。
文摘Atmospheric carbon dioxide(CO_(2))levels are escalating at an unprecedented rate,leading to the phenomenon of ocean acidification(OA).Parental exposure to acidification has the potential to enhance offspring resilience through cross-generation plasticity.In this study,we analyzed larval growth and transcriptomic profiles in the Pacific oyster,Crassostrea gigas,a species of significant ecological relevance,under both control and elevated CO_(2)conditions experienced by their parental generation.Our findings indicate that the oyster populations exposed to OA exhibited a higher incidence of abnormalities during the D-shaped larval stage,followed by accelerated growth at the eyed stage.Through a comparative transcriptomic investigation of eyed larvae(25 d after fertilization),we observed that parental exposure to OA substantially influenced the gene expression in the offspring.Genes associated with lipid catabolism and shell formation were notably upregulated in oysters with parental OA exposure,potentially playing a role in cross-generational conditioning and conferring resilience to OA stressors.These results underscore the profound impact of OA on oyster larval development via cross-generational mechanisms and shed light on the molecular underpinnings of cross-generation plasticity.
基金supported by the National Key R&D Program for Developing Basic Sciences [grant number 2022YFC3104805]the National Natural Science Foundation of China [grant numbers 92358302 and 42306219]+1 种基金supported by the Tai Shan Scholar Program [grant number tstp20231237]Laoshan Laboratory project [grant number LSKJ202300301]。
文摘This research evaluates the performance of an eddy-resolving forecast system(LFS)in simulating mesoscale eddies over the South China Sea(SCs)through a comparative analysis with satellite observations and the reanalysis dataset from the Global Ocean Physics Reanalysis product(CMEMS).The findings indicate that the spatial characteristics of eddy kinetic energy,number,and amplitude of coherent mesoscale eddies simulated by LFS exhibit a reasonable agreement with satellite observations.The reproduced seasonal variations are also comparable to outputs from the CMEMS reanalysis dataset.Nevertheless,certain systematic biases have also been identified.In the SCS,LFS generates approximately 17%fewer eddies than observed.Such biases are also evident in the CMEMS reanalysis dataset.Similar to the statistics shown in the CMEMS reanalysis dataset,both cyclonic and anticyclonic eddies are significantly weaker in LFS compared to the observations.Additionally,the composite three-dimensional structures of mesoscale eddies simulated by LFS exhibit a remarkable similarity to those identified in the CMEMS reanalysis datasets.This work lays the foundation for further studies using LFS to investigate the predictability of mesoscale eddies and enhance the accuracy of simulations.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFF0801400 and 2021YFF0704002)the Shandong Provincial Natural Science Foundation(Grant No.ZR2024LQX002)the National Science Foundation of China(Grant No.42176016).
文摘The Yellow Sea and Bohai Sea are among the global shelf seas susceptible to typhoons every year.Using observations and high-resolution numerical simulations,the current study investigates the dramatic changes in temperature and ocean heat content(OHC)of the Yellow Sea and Bohai Sea caused by Super Typhoon Maysak in early September 2020,which is representative of northward/northeastward-bypassing typhoons with centers just to the east of the study area.Temperature shows spatially coherent cooling in the upper mixed layer but warming in the subsurface layer in the majority of the offshore waters,due to wind-enhanced vertical mixing.In lower layers from the thermocline to sea bottom,temperature experiences significant warming in northeastern coastal waters of the Shandong Peninsula and in regions just off the Subei Shoal,but significant cooling in western coastal waters of the Korean Peninsula and southern coastal waters of the Shandong Peninsula.Significant temperature warming/cooling in lower layers is caused by coastal downwelling/upwelling.The total OHC of the study area decreases rapidly during Typhoon Maysak(2020)’s passage,which is generated comparably by latent heat loss at the sea surface and southward heat advection out of the study area at the southern boundary.Reduced shortwave radiation contributes positively but secondarily to the decreasing OHC during the first day.A numerical experiment suggests that Typhoon Maysak(2020)-induced OHC decline could have greatly affected the regional climate evolution in the following seasons.More studies are needed to fully understand the impacts of typhoons on regional climate changes in shelf seas at different time scales.
基金supported by the National Natural Science Foundation of China[grant numbers 41975087,U2242212,and 41975085]supported by the National Natural Science Foundation of China[grant number U2242212]。
文摘Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(ENSO)on summer precipitation in China.The inverse phase spatial distribution of sea surface temperature anomalies(SSTAs)in the southwest and northeast of the southern Indian Ocean is defined as the SIOD.Positive SIOD events(positive SSTAs in the southwest,negative SSTAs in the northeast)are associated with La Niña events(Central Pacific(CP)type),while negative SIOD events(negative SSTAs in the southwest,positive SSTAs in the northeast)are associated with El Niño events(Eastern Pacific(EP)type).Both SIOD and ENSO have certain impacts on summer precipitation in China.Precipitation in the Yangtze River basin decreases,while precipitation in southern China increases during pure positive SIOD(P_PSIOD)events.During pure negative SIOD(P_NSIOD)events,the changes in precipitation are exactly the opposite of those during P_PSIOD events,which may be due to differences in the cross-equatorial flow in the southern Indian Ocean,particularly in low-level Australian cross-equatorial flow.When positive SIOD and CP-type La Niña events occur simultaneously(PSIOD+La_Niña),precipitation increases in the Yangtze-Huaihe River basin,while it decreases in northern China.When negative SIOD and EP-type El Niño events occur simultaneously(NSIOD+El_Niño),precipitation in the Yangtze-Huaihe River basin is significantly lower than during P_NSIOD events.This is caused by differences in water vapor originating from the Pacific Ocean during different events.
