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Establishment of probabilistic model for Salmonella Enteritidis growth and inactivation under acid and osmotic pressure
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作者 Yujiao Shi Hong Liu +4 位作者 Baozhang Luo Yangtai Liu Siyuan Yue Qing Liu Qingli Dong 《Food Science and Human Wellness》 SCIE 2017年第4期176-186,共11页
The growth and survival characteristic of Salmonella Enteritidis under acidic and osmotic conditions were studied.Meanwhile,a probabilistic model based on the theory of cell division and mortality was established to p... The growth and survival characteristic of Salmonella Enteritidis under acidic and osmotic conditions were studied.Meanwhile,a probabilistic model based on the theory of cell division and mortality was established to predict the growth or inactivation of S.Enteritidis.The experimental results demonstrated that the growth curves of planktonic and detached cells showed a significant difference(p<0.05)under four conditions,including pH5.0+0.0%NaCl,pH7.0+4.0%NaCl,pH6.0+4.0%NaCl,and pH5.0+4.0%NaCl.And the established primary and secondary models could describe the growth of S.enteritis well by estimating four mathematics evaluation indexes,including determination coefficient(R2),root mean square error(RMSE),accuracy factor(Af)and bias factor(Bf).Moreover,sequential treatment of 15%NaCl stress followed by pH 4.5 stress was the best condition to inactivate S.Enteritidis in 10 h at 25◦C.The probabilistic model with Logistical or Weibullian form could also predict the inactivation of S.Enteritidis well,thus realize the unification of predictive model to some extent or generalization of inactivation model.Furthermore,the primary 4-parameter probabilistic model or generalized inactivation model had slightly higher applicability and reliability to describe the growth or inactivation of S.Enteritidis than Baranyi model or exponential inactivation model within the experimental range in this study. 展开更多
关键词 ACID Osmotic pressure Salmonella Enteritidis probabilistic model Unification GENERALIZATION
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Probabilistic Modeling of Oil Spills at the Exclusive Economic Zone of Cuba Using Petromar-3D Model
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作者 Alejandro Rodríguez Dayron Chang +6 位作者 Amilcar E. Calzada Dayana Carracedo Dailín Reyes Alexander Lobaina Reinaldo Casals Jessica Hernández Javier Cabrales 《Journal of Geoscience and Environment Protection》 2021年第6期21-34,共14页
This article shows the probabilistic modeling of hydrocarbon spills on the surface of the sea, using climatology data of oil spill trajectories yielded by applying the lagrangian model PETROMAR-3D. To achieve this goa... This article shows the probabilistic modeling of hydrocarbon spills on the surface of the sea, using climatology data of oil spill trajectories yielded by applying the lagrangian model PETROMAR-3D. To achieve this goal, several computing and statistical tools were used to develop the probabilistic modeling solution based in the methodology of Guo. Solution was implemented using a databases approach and SQL language. A case study is presented which is based on a hypothetical spill in a location inside the Exclusive Economic Zone of Cuba. Important outputs and products of probabilistic modeling were obtained, which are very useful for decision-makers and operators in charge to face oil spill accidents and prepare contingency plans to minimize its effects. In order to study the relationship between the initial trajectory and the arrival of hydrocarbons spills to the coast, a new approach is introduced as an incoming perspective for modeling. It consists in storage in databases the direction of movement of the oil slick at the first 24 hours. The probabilistic modeling solution presented is of great importance for hazard studies of oil spills in Cuban coastal areas. 展开更多
关键词 Oil Spill modeling Petromar Lagrangian model probabilistic modeling
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A Probabilistic Description of the Impact of Vaccine-Induced Immunity in the Dynamics of COVID-19 Transmission
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作者 Javier Blecua Juan Fernández-Recio José Manuel Gutiérrez 《Open Journal of Modelling and Simulation》 2024年第2期59-73,共15页
The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 t... The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 transmission have been reported. Among them, Bayesian probabilistic models of COVID-19 transmission dynamics have been very efficient in the interpretation of early data from the beginning of the pandemic, helping to estimate the impact of non-pharmacological measures in each country, and forecasting the evolution of the pandemic in different potential scenarios. These models use probability distribution curves to describe key dynamic aspects of the transmission, like the probability for every infected person of infecting other individuals, dying or recovering, with parameters obtained from experimental epidemiological data. However, the impact of vaccine-induced immunity, which has been key for controlling the public health emergency caused by the pandemic, has been more challenging to describe in these models, due to the complexity of experimental data. Here we report different probability distribution curves to model the acquisition and decay of immunity after vaccination. We discuss the mathematical background and how these models can be integrated in existing Bayesian probabilistic models to provide a good estimation of the dynamics of COVID-19 transmission during the entire pandemic period. 展开更多
关键词 COVID-19 Transmission Dynamics probabilistic model Bayesian Analysis Markov Chain Monte Carlo
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Probabilistic Modeling and Optimization of Real-Time Protocol for Multifunction Vehicle Bus 被引量:2
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作者 Lifan Su Min Zhou +1 位作者 Hai Wan Ming Gu 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2016年第5期561-569,共9页
In this paper, we present the modeling and optimization of a Real-Time Protocol(RTP) used in Train Communication Networks(TCN). In the proposed RTP, message arbitration is represented by a probabilistic model and the ... In this paper, we present the modeling and optimization of a Real-Time Protocol(RTP) used in Train Communication Networks(TCN). In the proposed RTP, message arbitration is represented by a probabilistic model and the number of arbitration checks is minimized by using the probability of device activity. Our optimized protocol is fully compatible with the original standard and can thus be implemented easily. The experimental results demonstrate that the proposed algorithm can reduce the number of checks by about 50%, thus significantly enhancing bandwidth. 展开更多
关键词 train communication network probabilistic modelling protocol optimization
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STOCHASTIC TRUST-REGION METHODS WITH TRUST-REGION RADIUS DEPENDING ON PROBABILISTIC MODELS 被引量:1
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作者 Xiaoyu Wang Ya-xiang Yuan 《Journal of Computational Mathematics》 SCIE CSCD 2022年第2期294-334,共41页
We present a stochastic trust-region model-based framework in which its radius is related to the probabilistic models.Especially,we propose a specific algorithm termed STRME,in which the trust-region radius depends li... We present a stochastic trust-region model-based framework in which its radius is related to the probabilistic models.Especially,we propose a specific algorithm termed STRME,in which the trust-region radius depends linearly on the gradient used to define the latest model.The complexity results of the STRME method in nonconvex,convex and strongly convex settings are presented,which match those of the existing algorithms based on probabilistic properties.In addition,several numerical experiments are carried out to reveal the benefits of the proposed methods compared to the existing stochastic trust-region methods and other relevant stochastic gradient methods. 展开更多
关键词 Trust-region methods Stochastic optimization probabilistic models Trust-region radius Global convergence
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A probabilistic model for assessing the reliability of wind farms in a power system 被引量:1
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作者 Mostafa HOSSEINPOUR Habib RAJABI MASHHADI Mohammad Ebrahim HAJIABAD 《Journal of Zhejiang University-Science C(Computers and Electronics)》 SCIE EI 2013年第6期464-474,共11页
Modeling the generation of a wind farm and its effect on power system reliability is a challenging task,largely due to the random behavior of the output power.In this paper,we propose a new probabilistic model for ass... Modeling the generation of a wind farm and its effect on power system reliability is a challenging task,largely due to the random behavior of the output power.In this paper,we propose a new probabilistic model for assessing the reliability of wind farms in a power system at hierarchical level II(HLII),using a Monte Carlo simulation.The proposed model shows the effect of correlation between wind and load on reliability calculation.It can also be used for identifying the priority of various points of the network for installing new wind farms,to promote the reliability of the whole system.A simple grid at hierarchical level I(HLI) and a network in the north-eastern region of Iran are studied.Simulation results showed that the correlation between wind and load significantly affects the reliability. 展开更多
关键词 Wind farm RELIABILITY PRIORITY probabilistic model
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Lane changing assistance strategy based on an improved probabilistic model of dynamic occupancy grids 被引量:1
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作者 Zhengcai YANG Zhenhai GAO +2 位作者 Fei GAO Xinyu WU Lei HE 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2021年第11期1492-1504,共13页
Lane changing assistance in autonomous vehicles is a popular research topic. Scene modeling of the driving area is a prerequisite for lane changing decision problems. A road environment representation method based on ... Lane changing assistance in autonomous vehicles is a popular research topic. Scene modeling of the driving area is a prerequisite for lane changing decision problems. A road environment representation method based on a dynamic occupancy grid is proposed in this study. The model encapsulates the data such as vehicle speed, obstacles, lane lines, and traffic rules into a form of spatial drivability probability. This information is compiled into a hash table, and the grid map is mapped into a hash map by means of hash function. A vehicle behavior decision cost equation is established with the model to help drivers make accurate vehicle lane changing decisions based on the principle of least cost, while considering influencing factors such as vehicle drivability, safety, and power. The feasibility of the lane changing assistance strategy is verified through vehicle tests, and the results show that the lane changing assistance system based on a probabilistic model of dynamic occupancy grids can provide lane changing assistance to drivers taking into consideration the dynamics and safety. 展开更多
关键词 Occupancy grids probabilistic model Lane changing assistance
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Probabilistic model for vessel-bridge collisions in the Three Gorges Reservoir 被引量:1
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作者 Bo GENG Hong WANG Junjie WANG 《Frontiers of Structural and Civil Engineering》 SCIE EI 2009年第3期279-285,共7页
Based on a field observation on vessel transit path of three bridges over the Yangtze River in the Three Gorges Reservoir,and an analysis of the geometric probabilistic model of transiting vessels in collision probabi... Based on a field observation on vessel transit path of three bridges over the Yangtze River in the Three Gorges Reservoir,and an analysis of the geometric probabilistic model of transiting vessels in collision probability calculation,the aberrancy angle and vessel velocity probabilistic model related with impact force,a probabilistic model is established and also verified by goodness-of-fit test.The vessel transit path distribution can be expressed by the normal distribution model.For the Three Gorges Reservoir,the mean and standard deviation adopt 0.2w and 0.1w,respectively(w is the channel width).The aberrancy angle distribution of vessels accepts maximum I distribution model,and its distribution parameters can be taken as 0.314 and 4.354.The velocity distribution of up-bound and down-bound vessels can also be expressed by the normal distribution model. 展开更多
关键词 vessel-bridge collision probabilistic model parameter statistics
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Induced Earthquake Hazard by Geothermal Power Plants: Statistical Evaluation and Probabilistic Modeling
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作者 Ali Khansefid Seyed Mahmoudreza Yadollahi +1 位作者 Gerhard Müller Francesca Taddei 《International Journal of Disaster Risk Science》 SCIE CSCD 2022年第5期758-777,共20页
This study statistically evaluated the characteristics of induced earthquakes by geothermal power plants(GPPs)and generated a probabilistic model for simulating stochastic seismic events.Four well-known power plant zo... This study statistically evaluated the characteristics of induced earthquakes by geothermal power plants(GPPs)and generated a probabilistic model for simulating stochastic seismic events.Four well-known power plant zones were selected worldwide from the United States,Germany,France,and New Zealand.The operational condition information,as well as the corresponding earthquake catalogs recorded in the vicinity of GPPs,were gathered from their commencement date.The statistical properties of events were studied elaborately.By using this proposed database,a probabilistic model was developed capable of generating the number of induced seismic events per month,their magnitude,focal depth,and distance from the epicenter to the power plant,randomly.All of these parameters are simulated as a function of power plant injection rate.Generally speaking,the model,introduced in this study,is a tool for engineers and scientists interested in the seismic risk assessment of built environments prone to induced seismicity produced by GPPs operation. 展开更多
关键词 Geothermal power plants Induced seismicity probabilistic modeling Seismic hazard Statistical analysis
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Probabilistic modeling for an integrated temporary acquired immunity with norovirus epidemiological data
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作者 Emmanuel de-Graft Johnson Owusu-Ansah Benedict Barnes +4 位作者 Robert Abaidoo Hald Tine Anders Dalsgaard Anders Permin Torben Wilde Schou 《Infectious Disease Modelling》 2019年第1期99-114,共16页
Integration of acquired immunity into microbial risk assessment for illness incidence is of no doubt essential for the study of susceptibility to illness.In this study,a probabilistic model was set up as dose response... Integration of acquired immunity into microbial risk assessment for illness incidence is of no doubt essential for the study of susceptibility to illness.In this study,a probabilistic model was set up as dose response for infection and a mathematical derivation was carried out by integrating immunity to obtain probability of illness models.Temporary acquire immunity from epidemiology studies which includes six different Norovirus transmission scenarios such as symptomatic individuals infectious,pre-and post-symptomatic infectiousness(low and high),innate genetic resistance,genogroup 2 type 4 and those with no immune boosting by asymptomatic infection were evaluated.Simulated results on illness inflation factor as a function of dose and exposure indicated that high frequency exposures had immense immunity build up even at high dose levels;hence minimized the probability of illness.Using Norovirus transmission dynamics data,results showed,and immunity included models had a reduction of 2e6 logs of magnitude difference in disease burden for both population and individual probable illness incidence.Additionally,the magnitude order of illness for each dose response remained largely the same for all transmission scenarios;symptomatic infectiousness and no immune boosting after asymptomatic infectiousness also remained the same throughout.With integration of epidemiological data on acquired immunity into the risk assessment,more realistic results were achieved signifying an overestimation of probable risk of illness when epidemiological immunity data are not included.This finding supported the call for rigorous integration of temporary acquired immunity in dose-response in all microbial risk assessments. 展开更多
关键词 Quantitative risk assessment probabilistic modeling Immunity integrated modeling
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Pavement performance model for road maintenance and repair planning: a review of predictive techniques
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作者 Krishna Singh Basnet Jagat Kumar Shrestha Rabindra Nath Shrestha 《Digital Transportation and Safety》 2023年第4期253-267,共15页
This paper provides a review of predictive analytics for roads,identifying gaps and limitations in current methodologies.It explores the implications of these limitations on accuracy and application,while also discuss... This paper provides a review of predictive analytics for roads,identifying gaps and limitations in current methodologies.It explores the implications of these limitations on accuracy and application,while also discussing how advanced predictive analytics can address these challenges.The article acknowledges the transformative shift brought about by technological advancements and increased computational capabilities.The degradation of pavement surfaces due to increased road users has resulted in safety and comfort issues.Researchers have conducted studies to assess pavement condition and predict future changes in pavement structure.Pavement Management Systems are crucial in developing prediction performance models that estimate pavement condition and degradation severity over time.Machine learning algorithms,artificial neural networks,and regression models have been used,with strengths and weaknesses.Researchers generally agree on their accuracy in estimating pavement condition considering factors like traffic,pavement age,and weather conditions.However,it is important to carefully select an appropriate prediction model to achieve a high-quality prediction performance system.Understanding the strengths and weaknesses of each model enables informed decisions for implementing prediction models that suit specific needs.The advancement of prediction models,coupled with innovative technologies,will contribute to improved pavement management and the overall safety and comfort of road users. 展开更多
关键词 Road Maintenance Prediction model Deterministic model probabilistic model Machine Learning model
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VIDEO MULTI-TARGET TRACKING BASED ON PROBABILISTIC GRAPHICAL MODEL
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作者 Xu Feng Huang Chenrong +1 位作者 Wu Zhengjun Xu Lizhong 《Journal of Electronics(China)》 2011年第4期548-557,共10页
In the technique of video multi-target tracking,the common particle filter can not deal well with uncertain relations among multiple targets.To solve this problem,many researchers use data association method to reduce... In the technique of video multi-target tracking,the common particle filter can not deal well with uncertain relations among multiple targets.To solve this problem,many researchers use data association method to reduce the multi-target uncertainty.However,the traditional data association method is difficult to track accurately when the target is occluded.To remove the occlusion in the video,combined with the theory of data association,this paper adopts the probabilistic graphical model for multi-target modeling and analysis of the targets relationship in the particle filter framework.Ex-perimental results show that the proposed algorithm can solve the occlusion problem better compared with the traditional algorithm. 展开更多
关键词 Video tracking Multi-target tracking Data association probabilistic graphical model Particle filter
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A probabilistic model based on the peak-over-threshold approach for risk assessment of airport controllers’performance
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作者 Lili Zu Yijie Lu Min Dong 《Journal of Safety Science and Resilience》 EI 2024年第1期110-118,共9页
Airport tower control plays an instrumental role in ensuring airport safety.However,obtaining objective,quantitative safety evaluations is challenging due to the unavailability of pertinent human operation data.This s... Airport tower control plays an instrumental role in ensuring airport safety.However,obtaining objective,quantitative safety evaluations is challenging due to the unavailability of pertinent human operation data.This study introduces a probabilistic model that combines aircraft dynamics and the peak-over-threshold(POT)approach to assess the safety performance of airport controllers.We applied the POT approach to model reaction times extracted from a radiotelephony dataset via a voice event detection algorithm.The model couples the risks of tower control and aircraft operation to analyze the influence of human factors.Using data from radiotele-phony communications and the Base of Aircraft Data(BADA)database,we compared risk levels across scenarios.Our findings revealed heightened airport control risks under low demand(0.374)compared to typical conditions(0.197).Furthermore,the risks associated with coupling under low demand exceeded those under typical de-mand,with the final approach stage presenting the highest risk(4.929×107).Our model underscores the significance of human factors and the implications of mental disconnects between pilots and controllers for safety risks.Collectively,these consistent findings affirm the reliability of our probabilistic model as an evaluative tool for evaluating the safety performance of airport tower controllers.The results also illuminate the path toward quantitative real-time safety evaluations for airport controllers within the industry.We recommend that airport regulators focus on the performance of airport controllers,particularly during the final approach stage. 展开更多
关键词 Safety evaluation Performance probabilistic model Task demand Airport controller
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Probabilistic Quantile Regression-Based Scour Estimation Considering Foundation Widths and Flood Conditions
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作者 Chen Wang Fayun Liang Jingru Li 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2021年第1期30-41,共12页
Scour has been widely accepted as a key reason for bridge failures.Bridges are susceptible and sensitive to the scour phenomenon,which describes the loss of riverbed sediments around the bridge supports because of flo... Scour has been widely accepted as a key reason for bridge failures.Bridges are susceptible and sensitive to the scour phenomenon,which describes the loss of riverbed sediments around the bridge supports because of flow.The carrying capacity of a deep-water foundation is influenced by the formation of a scour hole,which means that a severe scour can lead to a bridge failure without warning.Most of the current scour predictions are based on deterministic models,while other loads at bridges are usually provided as probabilistic values.To integrate scour factors with other loads in bridge design and research,a quantile regression model was utilized to estimate scour depth.Field data and experimental data from previous studies were collected to build the model.Moreover,scour estimations using the HEC-18 equation and the proposed method were compared.By using the“CCC(Calculate,Confirm,and Check)”procedure,the probabilistic concept could be used to calculate various scour depths with the targeted likelihood according to a specified chance of bridge failure.The study shows that with a sufficiently large and continuously updated database,the proposed model could present reasonable results and provide guidance for scour mitigation. 展开更多
关键词 bridge scour scour estimation quantile regression probabilistic model deterministic models
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Predictability of well construction time with multivariate probabilistic approach
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作者 LUU Quang-Hung LAU Man Fai +3 位作者 NG Sebastian P.H. TING Clement P.W. WEE Reuben THEN Patrick H.H. 《Petroleum Exploration and Development》 CSCD 2021年第4期987-998,共12页
Current univariate approach to predict the probability of well construction time has limited accuracy due to the fact that it ignores key factors affecting the time.In this study,we propose a multivariate probabilisti... Current univariate approach to predict the probability of well construction time has limited accuracy due to the fact that it ignores key factors affecting the time.In this study,we propose a multivariate probabilistic approach to predict the risks of well construction time.It takes advantage of an extended multi-dimensional Bernacchia–Pigolotti kernel density estimation technique and combines probability distributions by means of Monte-Carlo simulations to establish a depth-dependent probabilistic model.This method is applied to predict the durations of drilling phases of 192 wells,most of which are located in the AustraliaAsia region.Despite the challenge of gappy records,our model shows an excellent statistical agreement with the observed data.Our results suggested that the total time is longer than the trouble-free time by at least 4 days,and at most 12 days within the 10%–90% confidence interval.This model allows us to derive the likelihoods of duration for each phase at a certain depth and to generate inputs for training data-driven models,facilitating evaluation and prediction of the risks of an entire drilling operation. 展开更多
关键词 well construction time multivariate probabilistic modelling probabilistic approach Markov Chain Monte-Carlo
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Data Analysis of Multiplex Sequencing at SOLiD Platform:A Probabilistic Approach to Characterization and Reliability Increase
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作者 Fábio Manoel Franca Lobato Carlos Diego Damasceno +5 位作者 Daniela Soares Leite Andrea Kelly Ribeiro-dos-Santos Sylvain Darnet Carlos Renato Francês Nandamudi Lankalapalli Vijaykumar Adamo Lima de Santana 《American Journal of Molecular Biology》 2018年第1期26-38,共13页
New sequencing technologies such as Illumina/Solexa, SOLiD/ABI, and 454/Roche, revolutionized the biological researches. In this context, the SOLiD platform has a particular sequencing type, known as multiplex run, wh... New sequencing technologies such as Illumina/Solexa, SOLiD/ABI, and 454/Roche, revolutionized the biological researches. In this context, the SOLiD platform has a particular sequencing type, known as multiplex run, which enables the sequencing of several samples in a single run. It implies in cost reduction and simplifies the analysis of related samples. Meanwhile, this sequencing type requires an additional filtering step to ensure the reliability of the results. Thus, we propose in this paper a probabilistic model which considers the intrinsic characteristics of each sequencing to characterize multiplex runs and filter low-quality data, increasing the data analysis reliability of multiplex sequencing performed on SOLiD. The results show that the proposed model proves to be satisfactory due to: 1) identification of faults in the sequencing process;2) adaptation and development of new protocols for sample preparation;3) the assignment of a degree of confidence to the data generated;and 4) guiding a filtering process, without discarding useful sequences in an arbitrary manner. 展开更多
关键词 probabilistic modeling Health Informatics SOLiD Barcoding System Statistical Analysis Multiplex Sequencing
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A practical framework for performance-based reliability analysis of subway stations based on a faultestructure combined system
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作者 M.Ghorbanzadeh M.Hajihassani M.Kharghani 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第6期1406-1425,共20页
It is necessary to pay particular attention to the uncertainties that exist in an engineering problem to reduce the risk of seismic damage of infrastructures against natural hazards.Moreover,certain structural perform... It is necessary to pay particular attention to the uncertainties that exist in an engineering problem to reduce the risk of seismic damage of infrastructures against natural hazards.Moreover,certain structural performance levels should be satisfied during strong earthquakes.However,these performance levels have been only well described for aboveground structures.This study investigates the main uncertainties involved in the performance-based seismic analysis of a multi-story subway station.More than 100 pulse-like and no pulse-like ground motions have been selected.In this regard,an effective framework is presented,based on a set of nonlinear static and dynamic analyses performed by OpenSees code.The probabilistic seismic demand models for computing the free-field shear strain of soil and racking ratio of structure are proposed.These models result in less variability compared with existing relations,and make it possible to evaluate a wider range of uncertainties through reliability analysis in Rtx software using the Monte Carlo sampling method.This work is performed for three different structural performance levels(denoted as PL1ePL3).It is demonstrated that the error terms related to the magnitude and location of earthquake excitations and also the corresponding attenuation relationships have been the most important parameters.Therefore,using a faultestructure model would be inevitable for the reliability analysis of subway stations.It is found that the higher performance level(i.e.PL3)has more sensitivity to random variables than the others.In this condition,the pulse-like ground motions have a major contribution to the vulnerability of subway stations. 展开更多
关键词 Seismic hazard probabilistic models Reliability analysis Subway station
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Diffusionmodels for time-series applications: a survey
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作者 Lequan LIN Zhengkun LI +2 位作者 Ruikun LI Xuliang LI Junbin GAO 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2024年第1期19-41,共23页
Diffusion models, a family of generative models based on deep learning, have become increasinglyprominent in cutting-edge machine learning research. With distinguished performance in generating samples thatresemble th... Diffusion models, a family of generative models based on deep learning, have become increasinglyprominent in cutting-edge machine learning research. With distinguished performance in generating samples thatresemble the observed data, diffusion models are widely used in image, video, and text synthesis nowadays. Inrecent years, the concept of diffusion has been extended to time-series applications, and many powerful models havebeen developed. Considering the deficiency of a methodical summary and discourse on these models, we providethis survey as an elementary resource for new researchers in this area and to provide inspiration to motivate futureresearch. For better understanding, we include an introduction about the basics of diffusion models. Except forthis, we primarily focus on diffusion-based methods for time-series forecasting, imputation, and generation, andpresent them, separately, in three individual sections. We also compare different methods for the same applicationand highlight their connections if applicable. Finally, we conclude with the common limitation of diffusion-basedmethods and highlight potential future research directions. 展开更多
关键词 Diffusion models Time-series forecasting Time-series imputation Denoising diffusion probabilistic models Score-based generative models Stochastic differential equations
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Prediction of rockhead using a hybrid N-XGBoost machine learning framework 被引量:3
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作者 Xing Zhu Jian Chu +3 位作者 Kangda Wang Shifan Wu Wei Yan Kiefer Chiam 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2021年第6期1231-1245,共15页
The spatial information of rockhead is crucial for the design and construction of tunneling or underground excavation.Although the conventional site investigation methods(i.e.borehole drilling) could provide local eng... The spatial information of rockhead is crucial for the design and construction of tunneling or underground excavation.Although the conventional site investigation methods(i.e.borehole drilling) could provide local engineering geological information,the accurate prediction of the rockhead position with limited borehole data is still challenging due to its spatial variation and great uncertainties involved.With the development of computer science,machine learning(ML) has been proved to be a promising way to avoid subjective judgments by human beings and to establish complex relationships with mega data automatically.However,few studies have been reported on the adoption of ML models for the prediction of the rockhead position.In this paper,we proposed a robust probabilistic ML model for predicting the rockhead distribution using the spatial geographic information.The framework of the natural gradient boosting(NGBoost) algorithm combined with the extreme gradient boosting(XGBoost)is used as the basic learner.The XGBoost model was also compared with some other ML models such as the gradient boosting regression tree(GBRT),the light gradient boosting machine(LightGBM),the multivariate linear regression(MLR),the artificial neural network(ANN),and the support vector machine(SVM).The results demonstrate that the XGBoost algorithm,the core algorithm of the probabilistic NXGBoost model,outperformed the other conventional ML models with a coefficient of determination(R2)of 0.89 and a root mean squared error(RMSE) of 5.8 m for the prediction of rockhead position based on limited borehole data.The probabilistic N-XGBoost model not only achieved a higher prediction accuracy,but also provided a predictive estimation of the uncertainty.Thus,the proposed N-XGBoost probabilistic model has the potential to be used as a reliable and effective ML algorithm for the prediction of rockhead position in rock and geotechnical engineering. 展开更多
关键词 Rockhead Machine learning(ML) probabilistic model Gradient boosting
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Comparative Variance and Multiple Imputation Used for Missing Values in Land Price DataSet 被引量:1
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作者 Longqing Zhang Xinwei Zhang +2 位作者 Liping Bai Yanghong Zhang Feng Sun Changcheng Chen 《Computers, Materials & Continua》 SCIE EI 2019年第9期1175-1187,共13页
Based on the two-dimensional relation table,this paper studies the missing values in the sample data of land price of Shunde District of Foshan City.GeoDa software was used to eliminate the insignificant factors by st... Based on the two-dimensional relation table,this paper studies the missing values in the sample data of land price of Shunde District of Foshan City.GeoDa software was used to eliminate the insignificant factors by stepwise regression analysis;NORM software was adopted to construct the multiple imputation models;EM algorithm and the augmentation algorithm were applied to fit multiple linear regression equations to construct five different filling datasets.Statistical analysis is performed on the imputation data set in order to calculate the mean and variance of each data set,and the weight is determined according to the differences.Finally,comprehensive integration is implemented to achieve the imputation expression of missing values.The results showed that in the three missing cases where the PRICE variable was missing and the deletion rate was 5%,the PRICE variable was missing and the deletion rate was 10%,and the PRICE variable and the CBD variable were both missing.The new method compared to the traditional multiple filling methods of true value closer ratio is 75%to 25%,62.5%to 37.5%,100%to 0%.Therefore,the new method is obviously better than the traditional multiple imputation methods,and the missing value data estimated by the new method bears certain reference value. 展开更多
关键词 Imputation method multiple imputations probabilistic model
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