The novel structural reliability methodology presented in this study is especially well suited for multidimensional structural dynamics that are physically measured or numerically simulated over a representative timel...The novel structural reliability methodology presented in this study is especially well suited for multidimensional structural dynamics that are physically measured or numerically simulated over a representative timelapse.The Gaidai multivariate reliability method is applied to an operational offshore Jacket platform that operates in Bohai Bay.This study demonstrates the feasibility of this method to accurately estimate collapse risks in dynamic systems under in situ environmental stressors.Modern reliability approaches do not cope easily with the high dimensionality of real engineering dynamic systems,as well as nonlinear intercorrelations between various structural components.The Jacket offshore platform is chosen as the case study for this reliability analysis because of the presence of various hotspot stresses that synchronously arise in its structural parts.The authors provide a straightforward,precise method for estimating overall risks of operational failure,damage,or hazard for nonlinear multidimensional dynamic systems.The latter tool is important for offshore engineers during the design stage.展开更多
This paper investigates the reliability of internal marine combustion engines using an integrated approach that combines Fault Tree Analysis(FTA)and Bayesian Networks(BN).FTA provides a structured,top-down method for ...This paper investigates the reliability of internal marine combustion engines using an integrated approach that combines Fault Tree Analysis(FTA)and Bayesian Networks(BN).FTA provides a structured,top-down method for identifying critical failure modes and their root causes,while BN introduces flexibility in probabilistic reasoning,enabling dynamic updates based on new evidence.This dual methodology overcomes the limitations of static FTA models,offering a comprehensive framework for system reliability analysis.Critical failures,including External Leakage(ELU),Failure to Start(FTS),and Overheating(OHE),were identified as key risks.By incorporating redundancy into high-risk components such as pumps and batteries,the likelihood of these failures was significantly reduced.For instance,redundant pumps reduced the probability of ELU by 31.88%,while additional batteries decreased the occurrence of FTS by 36.45%.The results underscore the practical benefits of combining FTA and BN for enhancing system reliability,particularly in maritime applications where operational safety and efficiency are critical.This research provides valuable insights for maintenance planning and highlights the importance of redundancy in critical systems,especially as the industry transitions toward more autonomous vessels.展开更多
To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),supe...To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),super absorbent resin(SAP).The erosion mode and internal deterioration mechanism under salt freeze-thaw cycle and dry-wet cycle were explored.The results show that the addition of enhancing materials can effectively improve the resistance of concrete to salt freezing and sulfate erosion:the relevant indexes of concrete added with X-AP and T-AP are improved after salt freeze-thaw cycles;concrete added with SBTTIA shows optimal sulfate corrosion resistance;and concrete added with AP displays the best resistance to salt freezing.Microanalysis shows that the increase in the number of cycles decreases the generation of internal hydration products and defects in concrete mixed with enhancing materials and improves the related indexes.Based on the Wiener model analysis,the reliability of concrete with different lithologies and enhancing materials is improved,which may provide a reference for the application of manufactured sand concrete and enhancing materials in Northwest China,especially for the study of the improvement effects and mechanism of enhancing materials on the performance of concrete.展开更多
The calculation of fatigue stress ranges due to random waves and ice loads on offshore structures is discussed, and the corresponding accumulative fatigue damages of the structural members are evaluated. To evaluate t...The calculation of fatigue stress ranges due to random waves and ice loads on offshore structures is discussed, and the corresponding accumulative fatigue damages of the structural members are evaluated. To evaluate the fatigue damage to the structures more accurately, the Miner rule is modified considering the fuzziness of the concerned parameters, and a new model for fuzzy fatigue reliability analysis of offshore structures members is developed. Furthermore, an assessment method for predicting the dynamics of the fuzzy fatigue reliability of structural members is provided.展开更多
Corrosion and fatigue cracks are major threats to the structural integrity of aging offshore platforms. For the rational estimation of the safety levels of aging platforms, a global reliability assessment approach for...Corrosion and fatigue cracks are major threats to the structural integrity of aging offshore platforms. For the rational estimation of the safety levels of aging platforms, a global reliability assessment approach for aging offshore platforms with corrosion and fatigue cracks is presented in this paper. The base shear capacity is taken as the global ultimate strength of the offshore platforms. It is modeled as a random process that decreases with time in the presence of corrosion and fatigue crack propagation. And the corrosion and fatigue crack growth rates in the main members and key joints are modeled as random variables. A simulation method of the extreme wave loads which are applied to the structures of offshore platforms is proposed too. Furthermore, the statistics of global base shear capacity and extreme wave loads are obtained by Monte Carlo simulation method. On the basis of the limit state equation of global failure mode, the instantaneous reliability and time dependent reliability assessment methods are both presented in this paper. Finally the instantaneous reliability index and time dependent failure probability of a jacket platform are estimated with different ages in the demonstration example.展开更多
Ice load is the dominative load in the design of offshore platforms in the ice zone, and the extreme ice load is the key factor that affects the safety of platforms. The present paper studies the statistical propertie...Ice load is the dominative load in the design of offshore platforms in the ice zone, and the extreme ice load is the key factor that affects the safety of platforms. The present paper studies the statistical properties of the global resistance and the extreme responses of the jacket platforms in Bahai Bay, considering the randomness of ice load, dead load, steel elastic modulus, yield strength and structural member dimensions. Then, based on the above results, an efficient approximate method of the global reliability analysis for the offshore platforms is proposed, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. Finally, numerical examples of JZ20-2 MSW, JZ20-2NW and JZ20-2 MUQ offshore jacket platforms in the Bahai Bay demonstrate the satisfying efficiency, accuracy and applicability of the proposed method.展开更多
In consideration of the fuzzy constraint boundary and through analysis of structural reliability, a model of structural fuzzy optimum design is established based on reliability for offshore jacket platforms. According...In consideration of the fuzzy constraint boundary and through analysis of structural reliability, a model of structural fuzzy optimum design is established based on reliability for offshore jacket platforms. According to the characteristics of offshore jacket platforms, the tolerance coefficient of the constraint boundary is determined with the fuzzy optimization method. The optimum level cut set lambda*, which is the intersection of the fuzzy constraint set and fuzzy objective set, is determined with the bound search method, and then the fuzzy optimum solution to the fuzzy optimization problem is obtained. The central offshore platform SZ36-1 is designed with the fuzzy optimum model based on reliability; the results are compared with those from deterministic optimum design and fuzzy optimum design. The tendency of design variables in the above three methods and its reasons are analyzed. The results of an example show that the fuzzy optimum design based on reliability is stable and reliable.展开更多
The target reliability index has been effectively used as the best solution to deal with the relationship between the structural safety and the optimal economy in any structural design. However, the target reliability...The target reliability index has been effectively used as the best solution to deal with the relationship between the structural safety and the optimal economy in any structural design. However, the target reliability index for offshore jacket platforms based on different sea areas in China has never been calibrated. This paper presents an approach for its calibration, and suggests many kinds of associated load cases. The uncertainties of loads and structural resistance are mainly in- vestigated. The target reliability index for structural components, tubular joints and piles of offshore jacket plaffortns are discussed respectively in detail. Finally, through the calibrated results from the offshore jacket platforms of QK18-1, JZ20-2, SZ36-1 and BZ28-1 in the Bohai Bay, it is proposed to adopt 2.8 as the target reliability index of offshore jacket platforms in the Bohai Bay for a 25-year design period. The results provide significant reference for the design of offshore jacket platforms.展开更多
Owing to the ageing of the existing structures worldwide and the lack of codes for the continued safely management of structures during their lifetime, it is very necessary to develop a tool to evaluate their system r...Owing to the ageing of the existing structures worldwide and the lack of codes for the continued safely management of structures during their lifetime, it is very necessary to develop a tool to evaluate their system reliability over a time interval. In this paper, a method is proposed to analyze system reliability of existing jacket platforms. The influences of dint, crack and corrosion are considered. The mechanics characteristics of the existing jacket platforms to extreme loads are analyzed by use of the nonlinear mechanical analysis. The nonlinear interaction of pile-soil-structure is taken into consideration in the analysis. By use of FEM method and Monte Carlo simulation, the system reliability of the existing jacket platforul can be obtained. The method has been illustrated through application to BZ28-1 three jacket platforms which have operated for sixteen years. Advantages of the proposed method for analyzing the system reliability of the existing jacket platform is also highlighted.展开更多
Matrix method is being proposed for qualitative evaluation of the reliability of technical systems on a finite set of structural elements. We are introducing the criteria for qualitative assessment of the reliability ...Matrix method is being proposed for qualitative evaluation of the reliability of technical systems on a finite set of structural elements. We are introducing the criteria for qualitative assessment of the reliability in the form of structural reliability of the system as the probability of the troubleproof state of this system and the significancy of the individual elements in ensuring the structural reliability of the system as a general aggregate of conditional probabilities, which compose two (2 × 2) matrices of significancy for each element. We are using chain diagrams for solving the combinatronic problems and matrices for algorithmization of calculating procedures.展开更多
Autonomous Underwater Vehicles(AUVs)are pivotal for deep-sea exploration and resource exploitation,yet their reliability in extreme underwater environments remains a critical barrier to widespread deployment.Through s...Autonomous Underwater Vehicles(AUVs)are pivotal for deep-sea exploration and resource exploitation,yet their reliability in extreme underwater environments remains a critical barrier to widespread deployment.Through systematic analysis of 150 peer-reviewed studies employing mixed-methods research,this review yields three principal advancements to the reliability analysis of AUVs.First,based on the hierarchical functional division of AUVs into six subsystems(propulsion system,navigation system,communication system,power system,environmental detection system,and emergency system),this study systematically identifies the primary failure modes and potential failure causes of each subsystem,providing theoretical support for fault diagnosis and reliability optimization.Subsequently,a comprehensive review of AUV reliability analysis methods is conducted from three perspectives:analytical methods,simulated methods,and surrogate model methods.The applicability and limitations of each method are critically analyzed to offer insights into their suitability for engineering applications.Finally,the study highlights key challenges and research hotpots in AUV reliability analysis,including reliability analysis under limited data,AI-driven reliability analysis,and human reliability analysis.Furthermore,the potential of multi-sensor data fusion,edge computing,and advanced materials in enhancing AUV environmental adaptability and reliability is explored.展开更多
BACKGROUND During the gradual decline of physical and social functioning associated with end-stage renal disease,patients might experience a premonition of impending death,resulting in a series of pre-mourning grief r...BACKGROUND During the gradual decline of physical and social functioning associated with end-stage renal disease,patients might experience a premonition of impending death,resulting in a series of pre-mourning grief responses called preparatory grief.The preparatory grief in advanced cancer patients(PGAC)scale is the most widely used preparatory grief scale for patients on hemodialysis in China.AIM To verify the reliability and validity of the PGAC scale in patients on hemodialysis.METHODS In total,327 patients undergoing regular hemodialysis in the blood purification center of three grade-A tertiary hospitals in Guangdong and Guizhou provinces were selected by convenience sampling.The assessment was administered using the general information questionnaire and the Chinese version of PGAC.SPSS 25.0 and Amos 24.0 were used for item analysis,confirmatory factor analysis(CFA),convergent validity,and internal consistency reliability estimation.RESULTS In the modified Chinese version of PGAC,7 dimensions covering 27 total items were retained.CFA revealed a good fit of the factor model(chi-square degree of freedom=2.056,standardized root mean square residual=0.0479,root mean square error of approximation=0.0570,GFI=0.872,AGFI=0.841,IFI=0.931,CFI=0.930,TLI=0.919).The factor loadings of the items ranged 0.503-0.884.The composite reliability ranged 0.664-0.914,and the average variance extracted ranged 0.366-0.747.Cronbach’sαof the scale was 0.945,and Cronbach’sαfor various dimensions ranged 0.662-0.914.CONCLUSION The modified PGAC has good reliability and validity,and it can effectively measure preparatory grief in patients on hemodialysis.展开更多
Reliability analysis of soil slopes under rainfall is an important task for landslide risk assessment.Previous studies rarely contribute to the probabilistic analysis of slope stability under rainfall with reinforceme...Reliability analysis of soil slopes under rainfall is an important task for landslide risk assessment.Previous studies rarely contribute to the probabilistic analysis of slope stability under rainfall with reinforcement.A new method is suggested for reliability analysis of soil slopes stabilized with piles under rainfall.First,an efficient numerical model is exploited for slope stability analysis,where two types of slope failure modes,i.e.,plastic flow and local failure are considered.To address the blocking effect of piles during seepage analysis,the equivalent hydraulic conductivity of the pile area is estimated according to the effective medium theory.The stabilizing force of piles is investigated by an analytical approach.For saving computational effort,the response surface is established based on a multi-class classification model to predict two types of slope failure modes.Finally,uncertainties in soil parameters and rainfall events are both modelled,and the failure probability of soil slopes within a given time period is assessed through Monte Carlo simulation.An illustrative example is used to demonstrate the performance of the suggested method.It is found that the slope is mainly controlled by local failure.As the pile spacing increases,the likelihood of plastic flow significantly increases.As the piles are located near the slope crest,plastic flow is effectively prevented and the slope is better stabilized against rainfall.If rainfall uncertainties are not considered,the slope failure probability is significantly overestimated.Overall,this study can provide a useful guidance for the design of pile-stabilized slopes against rainfall infiltration.展开更多
The published article titled“Comparison of Structural Probabilistic and Non-Probabilistic Reliability Computational Methods under Big Data Condition”[1]has been retracted from Structural Durability&Health Monito...The published article titled“Comparison of Structural Probabilistic and Non-Probabilistic Reliability Computational Methods under Big Data Condition”[1]has been retracted from Structural Durability&Health Monitoring(SDHM),Vol.16,No.2,2022,pp.129–143.展开更多
The dynamic avalanche effect is a critical factor influencing the performance and reliability of the field-stop insulated gate bipolar transistors(FS-IGBT).Unclamped inductive switching(UIS)is the primary method for t...The dynamic avalanche effect is a critical factor influencing the performance and reliability of the field-stop insulated gate bipolar transistors(FS-IGBT).Unclamped inductive switching(UIS)is the primary method for testing the dynamic avalanche capability of FS-IGBTs.Numerous studies have demonstrated that factors such as device structure,avalanche-generating current filaments,and electrical parameters influence the dynamic avalanche effect of the FS-IGBT.However,few studies have focused on enhancing the avalanche reliability of the FS-IGBT by adjusting circuit parameters during operation.In this paper,the dynamic avalanche effect of the FS-IGBT under UIS conditions is comprehensively investigated through a series of comparative experiments with varying circuit parameters,including bus voltage V_(DC),gate voltage V_(G),gate resistance R_(g),load inductance L,and temperature TC.Furthermore,a method to enhance the dynamic avalanche reliability of the FS-IGBT under UIS by optimizing circuit parameters is proposed.In practical applications,reducing gate voltage,increasing load inductance,and lowering temperature can effectively improve the dynamic avalanche capability of the FS-IGBT.展开更多
Continuously increasing inflation is a major challenge in presenting reliable and relevant financial reports,especially in developing countries like Indonesia.This study aims to analyze the role of inflation accountin...Continuously increasing inflation is a major challenge in presenting reliable and relevant financial reports,especially in developing countries like Indonesia.This study aims to analyze the role of inflation accounting in increasing the reliability of financial reports during times of high inflation.With a qualitative-descriptive approach,this research examines two main methods in inflation accounting,namely General Price Level Accounting(GPLA)and Current Cost Accounting(CCA),and their impact on the value of assets,liabilities,income,and costs.The analysis results show that historical cost-based financial reports do not reflect actual economic conditions during inflation,so they can be misleading in decision making.The application of inflation accounting,through adjustments to purchasing power and current prices,has been proven to be able to increase the relevance and reliability of financial information.However,limitations in implementation in Indonesia are due to the lack of regulations and practical understanding regarding this method.Therefore,the application of inflation accounting is important in supporting the quality of financial reports and more accurate decision making amidst economic instability.展开更多
BACKGROUND The Victorian institute of sports assessment for patellar tendons questionnaire(VISA-P),a valid tool for patellar tendinopathy,has been used for patellofemoral pain(PFP).AIM To validate VISA-P in PFP.METHOD...BACKGROUND The Victorian institute of sports assessment for patellar tendons questionnaire(VISA-P),a valid tool for patellar tendinopathy,has been used for patellofemoral pain(PFP).AIM To validate VISA-P in PFP.METHODS Study of validity,responsiveness and feasibility following COSMIN.Inclusion criteria:Subjects with PFP,aged 18 to 55.Agreement among 10 experts on the relevance and clarity of each item using Aiken's V coefficient determined content validity.An exploratory factorial analysis established structural validity.The correlation of VISA-P with knee injury and osteoarthritis outcome score for PFP and Osteoarthritis(KOOS-PF)and Kujala patellofemoral score(KPS;specific for PFP)analyzed the construct validity.Internal consistency was calculated with Cronbach'sαand test-retest reliability with the intraclass correlation coefficient(ICC).Feasibility considered the subjects'self-completion time.RESULTS The sample consisted of 103 knees from 73 subjects(47 female/26 male;aged 34.9±13 SD).The items were relevant and clear,with the exception of item-8,which didn't reach an acceptable level of agreement on clarity.Exploratory factorial analysis found a 2-factor solution,which explained 63.48%of the variance.VISAP achieved a strong and significant correlation with KOOS-PF(Spearman rho=0.826;P<0.001)and KPS(Spearman rho=0.771;P<0.001).The questionnaire showed adequate reliability(Cronbach'sα:0.752;ICC:0.934;P<0.0001;95%CI:0.902-0.955).The mean self-completion time was 232±0.52 SD seconds.CONCLUSION VISA-P proved to be valid and reliable to functionally assess PFP and/or chondromalacia patella.VISA-P is a feasible tool in the clinical and research environment,quick and easy to complete.展开更多
文摘The novel structural reliability methodology presented in this study is especially well suited for multidimensional structural dynamics that are physically measured or numerically simulated over a representative timelapse.The Gaidai multivariate reliability method is applied to an operational offshore Jacket platform that operates in Bohai Bay.This study demonstrates the feasibility of this method to accurately estimate collapse risks in dynamic systems under in situ environmental stressors.Modern reliability approaches do not cope easily with the high dimensionality of real engineering dynamic systems,as well as nonlinear intercorrelations between various structural components.The Jacket offshore platform is chosen as the case study for this reliability analysis because of the presence of various hotspot stresses that synchronously arise in its structural parts.The authors provide a straightforward,precise method for estimating overall risks of operational failure,damage,or hazard for nonlinear multidimensional dynamic systems.The latter tool is important for offshore engineers during the design stage.
基金supported by Istanbul Technical University(Project No.45698)supported through the“Young Researchers’Career Development Project-training of doctoral students”of the Croatian Science Foundation.
文摘This paper investigates the reliability of internal marine combustion engines using an integrated approach that combines Fault Tree Analysis(FTA)and Bayesian Networks(BN).FTA provides a structured,top-down method for identifying critical failure modes and their root causes,while BN introduces flexibility in probabilistic reasoning,enabling dynamic updates based on new evidence.This dual methodology overcomes the limitations of static FTA models,offering a comprehensive framework for system reliability analysis.Critical failures,including External Leakage(ELU),Failure to Start(FTS),and Overheating(OHE),were identified as key risks.By incorporating redundancy into high-risk components such as pumps and batteries,the likelihood of these failures was significantly reduced.For instance,redundant pumps reduced the probability of ELU by 31.88%,while additional batteries decreased the occurrence of FTS by 36.45%.The results underscore the practical benefits of combining FTA and BN for enhancing system reliability,particularly in maritime applications where operational safety and efficiency are critical.This research provides valuable insights for maintenance planning and highlights the importance of redundancy in critical systems,especially as the industry transitions toward more autonomous vessels.
基金Funded by the National Natural Science Foundation of China(No.52178216)the Research on the Durability and Application of High-performance Concrete for Highway Engineering in the Cold and Arid Salt Areas of Northwest China(No.2022-24)the Construction Project of the Scientific Research Platform of Provincial Enterprises Supported by the Capital Operating Budget of Gansu Province(No.2023GZ018)。
文摘To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),super absorbent resin(SAP).The erosion mode and internal deterioration mechanism under salt freeze-thaw cycle and dry-wet cycle were explored.The results show that the addition of enhancing materials can effectively improve the resistance of concrete to salt freezing and sulfate erosion:the relevant indexes of concrete added with X-AP and T-AP are improved after salt freeze-thaw cycles;concrete added with SBTTIA shows optimal sulfate corrosion resistance;and concrete added with AP displays the best resistance to salt freezing.Microanalysis shows that the increase in the number of cycles decreases the generation of internal hydration products and defects in concrete mixed with enhancing materials and improves the related indexes.Based on the Wiener model analysis,the reliability of concrete with different lithologies and enhancing materials is improved,which may provide a reference for the application of manufactured sand concrete and enhancing materials in Northwest China,especially for the study of the improvement effects and mechanism of enhancing materials on the performance of concrete.
文摘The calculation of fatigue stress ranges due to random waves and ice loads on offshore structures is discussed, and the corresponding accumulative fatigue damages of the structural members are evaluated. To evaluate the fatigue damage to the structures more accurately, the Miner rule is modified considering the fuzziness of the concerned parameters, and a new model for fuzzy fatigue reliability analysis of offshore structures members is developed. Furthermore, an assessment method for predicting the dynamics of the fuzzy fatigue reliability of structural members is provided.
基金supported by the National Natural Science Foundation of China(Grant No.50609009)
文摘Corrosion and fatigue cracks are major threats to the structural integrity of aging offshore platforms. For the rational estimation of the safety levels of aging platforms, a global reliability assessment approach for aging offshore platforms with corrosion and fatigue cracks is presented in this paper. The base shear capacity is taken as the global ultimate strength of the offshore platforms. It is modeled as a random process that decreases with time in the presence of corrosion and fatigue crack propagation. And the corrosion and fatigue crack growth rates in the main members and key joints are modeled as random variables. A simulation method of the extreme wave loads which are applied to the structures of offshore platforms is proposed too. Furthermore, the statistics of global base shear capacity and extreme wave loads are obtained by Monte Carlo simulation method. On the basis of the limit state equation of global failure mode, the instantaneous reliability and time dependent reliability assessment methods are both presented in this paper. Finally the instantaneous reliability index and time dependent failure probability of a jacket platform are estimated with different ages in the demonstration example.
基金This work was financially supported by the National High Technology Research and Development Programof China(863Program,Grant No.2001AA602015)the National Natural Science Foundation of China(Grant No.50578028and No.10721062)the Programfor NewCentury Excellent Talents in University.
文摘Ice load is the dominative load in the design of offshore platforms in the ice zone, and the extreme ice load is the key factor that affects the safety of platforms. The present paper studies the statistical properties of the global resistance and the extreme responses of the jacket platforms in Bahai Bay, considering the randomness of ice load, dead load, steel elastic modulus, yield strength and structural member dimensions. Then, based on the above results, an efficient approximate method of the global reliability analysis for the offshore platforms is proposed, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. Finally, numerical examples of JZ20-2 MSW, JZ20-2NW and JZ20-2 MUQ offshore jacket platforms in the Bahai Bay demonstrate the satisfying efficiency, accuracy and applicability of the proposed method.
基金This research project was financially supported by the National Natural Science Foundation of China (Grant No. 59895410)
文摘In consideration of the fuzzy constraint boundary and through analysis of structural reliability, a model of structural fuzzy optimum design is established based on reliability for offshore jacket platforms. According to the characteristics of offshore jacket platforms, the tolerance coefficient of the constraint boundary is determined with the fuzzy optimization method. The optimum level cut set lambda*, which is the intersection of the fuzzy constraint set and fuzzy objective set, is determined with the bound search method, and then the fuzzy optimum solution to the fuzzy optimization problem is obtained. The central offshore platform SZ36-1 is designed with the fuzzy optimum model based on reliability; the results are compared with those from deterministic optimum design and fuzzy optimum design. The tendency of design variables in the above three methods and its reasons are analyzed. The results of an example show that the fuzzy optimum design based on reliability is stable and reliable.
文摘The target reliability index has been effectively used as the best solution to deal with the relationship between the structural safety and the optimal economy in any structural design. However, the target reliability index for offshore jacket platforms based on different sea areas in China has never been calibrated. This paper presents an approach for its calibration, and suggests many kinds of associated load cases. The uncertainties of loads and structural resistance are mainly in- vestigated. The target reliability index for structural components, tubular joints and piles of offshore jacket plaffortns are discussed respectively in detail. Finally, through the calibrated results from the offshore jacket platforms of QK18-1, JZ20-2, SZ36-1 and BZ28-1 in the Bohai Bay, it is proposed to adopt 2.8 as the target reliability index of offshore jacket platforms in the Bohai Bay for a 25-year design period. The results provide significant reference for the design of offshore jacket platforms.
基金the National High Technology Research and Development Programof China(863 Program,Grant No.2006AA09A109-5)
文摘Owing to the ageing of the existing structures worldwide and the lack of codes for the continued safely management of structures during their lifetime, it is very necessary to develop a tool to evaluate their system reliability over a time interval. In this paper, a method is proposed to analyze system reliability of existing jacket platforms. The influences of dint, crack and corrosion are considered. The mechanics characteristics of the existing jacket platforms to extreme loads are analyzed by use of the nonlinear mechanical analysis. The nonlinear interaction of pile-soil-structure is taken into consideration in the analysis. By use of FEM method and Monte Carlo simulation, the system reliability of the existing jacket platforul can be obtained. The method has been illustrated through application to BZ28-1 three jacket platforms which have operated for sixteen years. Advantages of the proposed method for analyzing the system reliability of the existing jacket platform is also highlighted.
文摘Matrix method is being proposed for qualitative evaluation of the reliability of technical systems on a finite set of structural elements. We are introducing the criteria for qualitative assessment of the reliability in the form of structural reliability of the system as the probability of the troubleproof state of this system and the significancy of the individual elements in ensuring the structural reliability of the system as a general aggregate of conditional probabilities, which compose two (2 × 2) matrices of significancy for each element. We are using chain diagrams for solving the combinatronic problems and matrices for algorithmization of calculating procedures.
基金The National Key R&D Program Projects(Grant No.2022YFC2803601)the Natural Science Foundation of Shandong Province(Grant No.ZR2021YQ29)+1 种基金the Natural Science Foundation of Heilongjiang Province(Grant No.YQ2024E036)the Taishan Scholars Project(Grant No.tsqn202312317).
文摘Autonomous Underwater Vehicles(AUVs)are pivotal for deep-sea exploration and resource exploitation,yet their reliability in extreme underwater environments remains a critical barrier to widespread deployment.Through systematic analysis of 150 peer-reviewed studies employing mixed-methods research,this review yields three principal advancements to the reliability analysis of AUVs.First,based on the hierarchical functional division of AUVs into six subsystems(propulsion system,navigation system,communication system,power system,environmental detection system,and emergency system),this study systematically identifies the primary failure modes and potential failure causes of each subsystem,providing theoretical support for fault diagnosis and reliability optimization.Subsequently,a comprehensive review of AUV reliability analysis methods is conducted from three perspectives:analytical methods,simulated methods,and surrogate model methods.The applicability and limitations of each method are critically analyzed to offer insights into their suitability for engineering applications.Finally,the study highlights key challenges and research hotpots in AUV reliability analysis,including reliability analysis under limited data,AI-driven reliability analysis,and human reliability analysis.Furthermore,the potential of multi-sensor data fusion,edge computing,and advanced materials in enhancing AUV environmental adaptability and reliability is explored.
文摘BACKGROUND During the gradual decline of physical and social functioning associated with end-stage renal disease,patients might experience a premonition of impending death,resulting in a series of pre-mourning grief responses called preparatory grief.The preparatory grief in advanced cancer patients(PGAC)scale is the most widely used preparatory grief scale for patients on hemodialysis in China.AIM To verify the reliability and validity of the PGAC scale in patients on hemodialysis.METHODS In total,327 patients undergoing regular hemodialysis in the blood purification center of three grade-A tertiary hospitals in Guangdong and Guizhou provinces were selected by convenience sampling.The assessment was administered using the general information questionnaire and the Chinese version of PGAC.SPSS 25.0 and Amos 24.0 were used for item analysis,confirmatory factor analysis(CFA),convergent validity,and internal consistency reliability estimation.RESULTS In the modified Chinese version of PGAC,7 dimensions covering 27 total items were retained.CFA revealed a good fit of the factor model(chi-square degree of freedom=2.056,standardized root mean square residual=0.0479,root mean square error of approximation=0.0570,GFI=0.872,AGFI=0.841,IFI=0.931,CFI=0.930,TLI=0.919).The factor loadings of the items ranged 0.503-0.884.The composite reliability ranged 0.664-0.914,and the average variance extracted ranged 0.366-0.747.Cronbach’sαof the scale was 0.945,and Cronbach’sαfor various dimensions ranged 0.662-0.914.CONCLUSION The modified PGAC has good reliability and validity,and it can effectively measure preparatory grief in patients on hemodialysis.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB2600504)the National Natural Science Foundation of China(Grant No.42072302)the Postdoctoral Fellowship Program of CPSF(Grant No.GZB20240533).
文摘Reliability analysis of soil slopes under rainfall is an important task for landslide risk assessment.Previous studies rarely contribute to the probabilistic analysis of slope stability under rainfall with reinforcement.A new method is suggested for reliability analysis of soil slopes stabilized with piles under rainfall.First,an efficient numerical model is exploited for slope stability analysis,where two types of slope failure modes,i.e.,plastic flow and local failure are considered.To address the blocking effect of piles during seepage analysis,the equivalent hydraulic conductivity of the pile area is estimated according to the effective medium theory.The stabilizing force of piles is investigated by an analytical approach.For saving computational effort,the response surface is established based on a multi-class classification model to predict two types of slope failure modes.Finally,uncertainties in soil parameters and rainfall events are both modelled,and the failure probability of soil slopes within a given time period is assessed through Monte Carlo simulation.An illustrative example is used to demonstrate the performance of the suggested method.It is found that the slope is mainly controlled by local failure.As the pile spacing increases,the likelihood of plastic flow significantly increases.As the piles are located near the slope crest,plastic flow is effectively prevented and the slope is better stabilized against rainfall.If rainfall uncertainties are not considered,the slope failure probability is significantly overestimated.Overall,this study can provide a useful guidance for the design of pile-stabilized slopes against rainfall infiltration.
文摘The published article titled“Comparison of Structural Probabilistic and Non-Probabilistic Reliability Computational Methods under Big Data Condition”[1]has been retracted from Structural Durability&Health Monitoring(SDHM),Vol.16,No.2,2022,pp.129–143.
基金supported in part by the National Natural Science Foundation of China under Grant 62071073in part by the Fundamental Research Funds for Central Universities under Grant 2023CDJXY-041in part by the Foundation from Guangxi Key Laboratory of Optoelectronic Information Processing under Grant GD20201.
文摘The dynamic avalanche effect is a critical factor influencing the performance and reliability of the field-stop insulated gate bipolar transistors(FS-IGBT).Unclamped inductive switching(UIS)is the primary method for testing the dynamic avalanche capability of FS-IGBTs.Numerous studies have demonstrated that factors such as device structure,avalanche-generating current filaments,and electrical parameters influence the dynamic avalanche effect of the FS-IGBT.However,few studies have focused on enhancing the avalanche reliability of the FS-IGBT by adjusting circuit parameters during operation.In this paper,the dynamic avalanche effect of the FS-IGBT under UIS conditions is comprehensively investigated through a series of comparative experiments with varying circuit parameters,including bus voltage V_(DC),gate voltage V_(G),gate resistance R_(g),load inductance L,and temperature TC.Furthermore,a method to enhance the dynamic avalanche reliability of the FS-IGBT under UIS by optimizing circuit parameters is proposed.In practical applications,reducing gate voltage,increasing load inductance,and lowering temperature can effectively improve the dynamic avalanche capability of the FS-IGBT.
文摘Continuously increasing inflation is a major challenge in presenting reliable and relevant financial reports,especially in developing countries like Indonesia.This study aims to analyze the role of inflation accounting in increasing the reliability of financial reports during times of high inflation.With a qualitative-descriptive approach,this research examines two main methods in inflation accounting,namely General Price Level Accounting(GPLA)and Current Cost Accounting(CCA),and their impact on the value of assets,liabilities,income,and costs.The analysis results show that historical cost-based financial reports do not reflect actual economic conditions during inflation,so they can be misleading in decision making.The application of inflation accounting,through adjustments to purchasing power and current prices,has been proven to be able to increase the relevance and reliability of financial information.However,limitations in implementation in Indonesia are due to the lack of regulations and practical understanding regarding this method.Therefore,the application of inflation accounting is important in supporting the quality of financial reports and more accurate decision making amidst economic instability.
文摘BACKGROUND The Victorian institute of sports assessment for patellar tendons questionnaire(VISA-P),a valid tool for patellar tendinopathy,has been used for patellofemoral pain(PFP).AIM To validate VISA-P in PFP.METHODS Study of validity,responsiveness and feasibility following COSMIN.Inclusion criteria:Subjects with PFP,aged 18 to 55.Agreement among 10 experts on the relevance and clarity of each item using Aiken's V coefficient determined content validity.An exploratory factorial analysis established structural validity.The correlation of VISA-P with knee injury and osteoarthritis outcome score for PFP and Osteoarthritis(KOOS-PF)and Kujala patellofemoral score(KPS;specific for PFP)analyzed the construct validity.Internal consistency was calculated with Cronbach'sαand test-retest reliability with the intraclass correlation coefficient(ICC).Feasibility considered the subjects'self-completion time.RESULTS The sample consisted of 103 knees from 73 subjects(47 female/26 male;aged 34.9±13 SD).The items were relevant and clear,with the exception of item-8,which didn't reach an acceptable level of agreement on clarity.Exploratory factorial analysis found a 2-factor solution,which explained 63.48%of the variance.VISAP achieved a strong and significant correlation with KOOS-PF(Spearman rho=0.826;P<0.001)and KPS(Spearman rho=0.771;P<0.001).The questionnaire showed adequate reliability(Cronbach'sα:0.752;ICC:0.934;P<0.0001;95%CI:0.902-0.955).The mean self-completion time was 232±0.52 SD seconds.CONCLUSION VISA-P proved to be valid and reliable to functionally assess PFP and/or chondromalacia patella.VISA-P is a feasible tool in the clinical and research environment,quick and easy to complete.
