AIM To explore the relationship between collagen proportionate area(CPA) and portal hypertension-related clinical manifestations in alcoholic liver disease(ALD).METHODS Retrospective study with chart review of patient...AIM To explore the relationship between collagen proportionate area(CPA) and portal hypertension-related clinical manifestations in alcoholic liver disease(ALD).METHODS Retrospective study with chart review of patients with ALD adressed to our center between January 2012 and December 2013 for a transjugular liver biopsy(TJLB) and hepatic hemodynamic study. Patients were included if they met the following criteria:(1) Medical indication for a liver biopsy in the setting of ALD;(2) recent(< 15 d) clinical, radiological, endoscopic and biological data available; and(3) estimated follow-up of at least 6 mo. Liver tissue from cirrhotic subjects obtained from transjugular liver biopsies was stained with Picro Sirius red and computer-assisted digital image analysis to determine fibrosis density using CPA was performed. RESULTS We included 61 patients with alcoholic ALD, subdivided in 41 active alcohol drinkers and 20 durably abstinent patients. Nine healthy liver donors served as controls. Mean CPA in patients with ALD was 7.1%, with no difference between active drinkers and abstinent patients(P = 0.17). Using a fibrosis density cutoff of 5%, we observed a positive correlation between high fibrosis density and the hepatic venous pressure gradient(HVPG) only in active drinkers(P = 0.02). At 12-mo of follow-up, in the group of active alcohol drinkers, patients reaching a composite outcome showed a higher HVPG value as compared to those who did not(18.5 mm Hg vs 14.5 mm Hg P < 0.04) whereas CPA values were similar(6.9% vs 11%, P = 0.23).CONCLUSION In active alcoholic ALD, CPA correlates to portal pressure but only HVPG predicts clinical events, pointing to the role of alcohol as a modulator of portal hypertension.展开更多
BACKGROUND: The accurate assessment of the degree of hepatic fibrosis plays a critical role in guiding the diagnosis, treatment and prognostic assessment of chronic liver diseases. Liver biopsy is currently the most r...BACKGROUND: The accurate assessment of the degree of hepatic fibrosis plays a critical role in guiding the diagnosis, treatment and prognostic assessment of chronic liver diseases. Liver biopsy is currently the most reliable method to evaluate the severity of hepatic fibrosis. However, liver biopsy is an invasive procedure associated with morbidity and mortality, and has several limitations in patients with decompensated cirrhosis. There is no report on the collagen proportionate area (CPA) of liver tissue in the decompensated stage of cirrhosis. This study aimed to determine the CPA of resected liver tissue samples from patients with HBV-related decompensated cirrhosis using digital image analysis, and to analyze the relationship between the CPA and liver functional reserve. METHODS: Fifty-three resected liver tissue samples from liver transplant patients with chronic hepatitis B-induced decompensated cirrhosis were stained with Masson’s trichrome, and the CPA in these samples was quantitatively determined using digital image analysis. The values of relevant liver function just before liver transplantation, the CPA in liver tissue, and their correlation were analyzed. RESULTS: The mean CPA at the decompensated stage of cirrhosis was 35.93±14.42% (11.24%-63.41%). The correlation coefficients of the CPA with a model for end-stage liver disease score, serum total bilirubin and international standard ratio of prothrombin B were 0.553, 0.519 and 0.533, respectively (P<0.001). With increasing CPA values, the three indices reflecting liver functional reserve also changed significantly.CONCLUSIONS: The degree of fibrosis may be correlated with the functional reserve. With the advancement of fibrosis, the liver functional reserve is attenuated accordingly.展开更多
In this paper after analyzing the adaptation process of the proportionate normalized least mean square(PNLMS) algorithm, a statistical model is obtained to describe the convergence process of each adaptive filter coef...In this paper after analyzing the adaptation process of the proportionate normalized least mean square(PNLMS) algorithm, a statistical model is obtained to describe the convergence process of each adaptive filter coefcient. Inspired by this result, a modified PNLMS algorithm based on precise magnitude estimate is proposed. The simulation results indicate that in contrast to the traditional PNLMS algorithm, the proposed algorithm achieves faster convergence speed in the initial convergence state and lower misalignment in the stead stage with much less computational complexity.展开更多
Aiming at the problemthat the traditional short-circuit current calculationmethod is not applicable to Distributed Generation(DG)accessing the distribution network,the paper proposes a short-circuit current partitioni...Aiming at the problemthat the traditional short-circuit current calculationmethod is not applicable to Distributed Generation(DG)accessing the distribution network,the paper proposes a short-circuit current partitioning calculation method considering the degree of voltage drop at the grid-connected point of DG.Firstly,the output characteristics of DG in the process of low voltage ride through are analyzed,and the equivalent output model of DG in the fault state is obtained.Secondly,by studying the network voltage distribution law after fault in distribution networks under different DG penetration rates,the degree of voltage drop at the grid-connected point of DG is used as a partition index to partition the distribution network.Then,iterative computation is performed within each partition,and data are transferred between partitions through split nodes to realize the fast partition calculation of short-circuit current for high proportion DG access to distribution network,which solves the problems of long iteration time and large calculation error of traditional short-circuit current.Finally,a 62-node real distribution network model containing a high proportion of DG access is constructed onMATLAB/Simulink,and the simulation verifies the effectiveness of the short-circuit current partitioning calculation method proposed in the paper,and its calculation speed is improved by 48.35%compared with the global iteration method.展开更多
Sample size determination typically relies on a power analysis based on a frequentist conditional approach. This latter can be seen as a particular case of the two-priors approach, which allows to build four distinct ...Sample size determination typically relies on a power analysis based on a frequentist conditional approach. This latter can be seen as a particular case of the two-priors approach, which allows to build four distinct power functions to select the optimal sample size. We revise this approach when the focus is on testing a single binomial proportion. We consider exact methods and introduce a conservative criterion to account for the typical non-monotonic behavior of the power functions, when dealing with discrete data. The main purpose of this paper is to present a Shiny App providing a user-friendly, interactive tool to apply these criteria. The app also provides specific tools to elicit the analysis and the design prior distributions, which are the core of the two-priors approach.展开更多
为提升船用汽轮发电机组大幅变工况时的控制精度和鲁棒性,以船用汽轮机调节系统各部件的模块化数学模型为基础,建立汽轮机组数字电液(digital electric hydraulic,DEH)闭环模糊比例、积分、微分(proportion integration derivative,PID...为提升船用汽轮发电机组大幅变工况时的控制精度和鲁棒性,以船用汽轮机调节系统各部件的模块化数学模型为基础,建立汽轮机组数字电液(digital electric hydraulic,DEH)闭环模糊比例、积分、微分(proportion integration derivative,PID)控制模型;融合遗传算法的选择、交叉、变异和自适应递减权重法,提出遗传粒子群智能优化算法,并结合标准测试函数验证提出算法具有较高的收敛速度和精度;基于遗传粒子群智能优化算法建立汽轮机变工况自适应智能模糊PID控制模型,实现模糊PID的量化因子与比例因子最优化设计,进而开展船用汽轮发电机组大幅变工况动态特性及扰动因素影响分析,结果表明本文建立的自适应智能模糊PID控制模型具有更好的控制稳态性能与鲁棒性,为船用汽轮机组大幅度变工况智能控制优化设计提供了有力的技术支撑。展开更多
In coal mining,rock strata are fractured under cyclic loading and unloading to form fracture channels.Fracture channels are the main flow narrows for gas.Therefore,expounding the flow conductivity of fracture channels...In coal mining,rock strata are fractured under cyclic loading and unloading to form fracture channels.Fracture channels are the main flow narrows for gas.Therefore,expounding the flow conductivity of fracture channels in rocks on fluids is significant for gas flow in rock strata.In this regard,graded incremental cyclic loading and unloading experiments were conducted on sandstones with different initial stress levels.Then,the three-dimensional models for fracture channels in sandstones were established.Finally,the fracture channel percentages were used to reflect the flow conductivity of fracture channels.The study revealed how the particle size distribution of fractured sandstone affects the formation and expansion of fracture channels.It was found that a smaller proportion of large blocks and a higher proportion of small blocks after sandstone fails contribute more to the formation of fracture channels.The proportion of fracture channels in fractured rock can indicate the flow conductivity of those channels.When the proportion of fracture channels varies gently,fluids flow evenly through those channels.However,if the proportion of fracture channels varies significantly,it can greatly affect the flow rate of fluids.The research results contribute to revealing the morphological evolution and flow conductivity of fracture channels in sandstone and then provide a theoretical basis for clarifying the gas flow pattern in the rock strata of coal mines.展开更多
The development of solid waste resources as constituent materials for wet shotcrete has significant economic and environmental advantages. In this study, the concept of using tailings as aggregate and fly ash and slag...The development of solid waste resources as constituent materials for wet shotcrete has significant economic and environmental advantages. In this study, the concept of using tailings as aggregate and fly ash and slag powder as auxiliary cementitious material is proposed and experiments are carried out by response surface methodology(RSM). Multivariate nonlinear response models are constructed to investigate the effect of factors on the uniaxial compressive strength(UCS) of tailings wet shotcrete(TWSC). The UCS of TWSC is predicted and optimized by constructing Gaussian process regression(GPR) and genetic algorithm(GA). The UCS of TWSC is gradually enhanced with the increase of slag powder dosage and fineness modulus, and it is enhanced first and then decreased with the increase of fly ash dosage. The microstructure of TWSC has the highest gray value and the highest UCS when the fly ash dosage is about 120 kg·m^(-3). The GPR–GA model constructed in this study achieves high accuracy prediction and optimization of the UCS of TWSC under multi-factor conditions.展开更多
In order to comprehensively utilize the remaining bamboo residue of bamboo products,this paper presents a research on recycling the bamboo fibers from bamboo residue for improving the performance of the asphalt mixtur...In order to comprehensively utilize the remaining bamboo residue of bamboo products,this paper presents a research on recycling the bamboo fibers from bamboo residue for improving the performance of the asphalt mixtures.First of all,the basic performance parameters of sinocalamus affinis fiber,phyllostachys pubescens fiber,green bamboo fiber were tested and analyzed,and the optimal content and length were put forward.Then,the mix ratio design of the bamboo fiber modified asphalt mixture was further designed through the response surface method,and was verified the rationality of the mix ratio.Finally,the mixture specimens were made according to the experimental design mix ratio,and the high temperature,low temperature performance and moisture susceptibility of the bamboo fiber modified mixtures asphalt were tested.The results showed that the high temperature performance,low temperature performance and moisture susceptibility of bamboo fiber modified asphalt mixtures were improved compared with the performance of SBS modified asphalt mixture.When the length of bamboo fiber is 7.25 mm and the content of 0.22%,the road performance of the asphalt mixture was optimal.Consequentially,the decomposition of bamboo residue into bamboo fiber and its application in asphalt pavement can improve the reuse of bamboo waste,with remarkable environmental benefits and great promotion value.展开更多
Tailings known as solid waste are generated by the mining industry.The development of tailings as wet shotcrete aggregates has significant economic and environmental benefits.The fine particle size of the tailings res...Tailings known as solid waste are generated by the mining industry.The development of tailings as wet shotcrete aggregates has significant economic and environmental benefits.The fine particle size of the tailings results in a large consumption of traditional cement as a cementitious material and insignificant improvement in strength.Therefore,a composite cementitious system of cement and solid waste resources(fly ash and slag powder)is explored for this study.In this paper,the response surface methodology(RSM)is used to optimize the experimental design and a multivariate nonlinear response model with cement,fly ash and slag powder contents as variables are constructed,which can investigate the effect of the composite cementitious system on the strength of tailing wet shotcrete(TWSC).In addition,the information entropy(IE)is introduced and combined with the RSM to evaluate the composite cementitious system.Finally,the desirability function(DF)combined with RSM is used to optimize the composite cementitious system.The results show that the response model constructed in this paper has R^(2)=0.96 and P-value<0.01(the test result of the model is P-value<0.01),which indicates that the model has high reliability.The higher the content of slag powder and cement in the composite cementitious system,the higher the strength and comprehensive score of the TWSC.There is a critical value of fly ash content,which makes the maximum cementation of the composite cementing system.The optimal mix proportion of the composite cementitious system is obtained based on RSM-DF,which leads to the strength of TWSC at different curing time to achieve the expected index.展开更多
Aiming at solving the problems of response lag and lack of precision and stability in constant grinding force control of industrial robot belts,a constant force control strategy combining fuzzy control and proportion ...Aiming at solving the problems of response lag and lack of precision and stability in constant grinding force control of industrial robot belts,a constant force control strategy combining fuzzy control and proportion integration differentiation(PID)was proposed by analyzing the signal transmission process and the dynamic characteristics of the grinding mechanism.The simulation results showed that compared with the classical PID control strategy,the system adjustment time was shortened by 98.7%,the overshoot was reduced by 5.1%,and the control error was 0.2%-0.5%when the system was stabilized.The optimized fuzzy control system had fast adjustment speeds,precise force control and stability.The experimental analysis of the surface morphology of the machined blade was carried out by the industrial robot abrasive grinding mechanism,and the correctness of the theoretical analysis and the effectiveness of the control strategy were verified.展开更多
In this paper,based on the process data of evaluating the benchmark land prices of collective construction land and agricultural land,the score of influencing factors is calculated,and a regression model between value...In this paper,based on the process data of evaluating the benchmark land prices of collective construction land and agricultural land,the score of influencing factors is calculated,and a regression model between value-added benefits and influencing factors is established.According to the contribution of the government and collectives to value-added benefits,the distribution proportions of different purposes and levels are calculated.The research results show that there are significant differences in the distribution proportion of value-added income among different levels.The government distribution proportion decreases with the decrease of level,while the collective distribution proportion increases with the decrease of level.For each level of decrease in commercial service industry land and industrial and mining warehousing industry land,the government distribution proportion decreases by an average of 2.66%and 2.34%,while the collective distribution proportion increases by an average of 2.66%and 2.34%,respectively.The average distribution proportion of the government in the value-added income of commercial service industry land is 31.58%,which is much higher than the average income of 23.68%in the value-added income of industrial and mining warehousing industry land.展开更多
BACKGROUND Cancer diagnosis is increasing around the world and in the Democratic Republic of the Congo(DRC).The proportion of thyroid cancer has increased over the past three decades.There are very few studies on canc...BACKGROUND Cancer diagnosis is increasing around the world and in the Democratic Republic of the Congo(DRC).The proportion of thyroid cancer has increased over the past three decades.There are very few studies on cancer epidemiology,and in particular on thyroid cancer in the DRC.AIM To establish the most recent proportion of thyroid cancer in the DRC compared to other cancers.METHODS This is a retrospective and descriptive study of 6106 consecutive cancer cases listed in the pathological registers of 4 Laboratories in the city of Kinshasa.This study included all cancer cases recorded in the registers between 2005 and 2019.RESULTS From a sample of 6106 patients,including all cancer types,68.3%cases were female and 31.7%were male.Breast and cervical cancer were the most common types of cancer in women and,prostate and skin cancer were the most common types in men.Thyroid cancer was sixth in proportion in women and eleventh in men compared to all cancers.Papillary carcinoma was the most common of thyroid cancers.Rare cancers such as anaplastic and medullary thyroid carcinomas had a proportion of 7%and 2%,respectively.CONCLUSION Newer diagnostic tools led to a surge in cancer diagnoses in the DRC.Thyroid cancer has more than doubled its proportion over the last several decades in the country.展开更多
A multi-qubit pure quantum state is called separable when it can be factored as the tensor product of 1-qubit pure quantum states.Factorizing a general multi-qubit pure quantum state into the tensor product of its fac...A multi-qubit pure quantum state is called separable when it can be factored as the tensor product of 1-qubit pure quantum states.Factorizing a general multi-qubit pure quantum state into the tensor product of its factors(pure states containing a smaller number of qubits)can be a challenging task,especially for highly entangled states.A new criterion based on the proportionality of the rows of certain associated matrices for the existence of certain factorization and a factorization algorithm that follows from this criterion for systematically extracting all the factors is developed in this paper.3-qubit pure states play a crucial role in quantum computing and quantum information processing.For various applications,the well-known 3-qubit GHZ state which contains two nonzero terms,and the 3-qubit W state which contains three nonzero terms,have been studied extensively.Using the new factorization algorithm developed here we perform a complete analysis vis-à-vis entanglement of 3-qubit states that contain exactly two nonzero terms and exactly three nonzero terms.展开更多
汽车悬架控制系统是一个由较多非线性因素共同作用的复杂系统,针对传统PID控制效果不理想的问题,通过数值拟合的方式引入弹簧与阻尼等非线性影响因素,建立1/4汽车悬架非线性动力学模型,借鉴免疫反馈原理,结合积分控制的规律,提出一种模...汽车悬架控制系统是一个由较多非线性因素共同作用的复杂系统,针对传统PID控制效果不理想的问题,通过数值拟合的方式引入弹簧与阻尼等非线性影响因素,建立1/4汽车悬架非线性动力学模型,借鉴免疫反馈原理,结合积分控制的规律,提出一种模糊免疫PID(proportion integral derivative)控制方法,并利用免疫进化算法进行参数优化设计。仿真结果表明,该方法在汽车非线性悬架控制系统中可行且有效,其控制器性能也优于常规的PID控制器,具有更好的响应特性,同时也提高了汽车的操作稳定性和乘坐舒适性。展开更多
Iris recognition enjoys universality, high degree of uniqueness and moderate user co-operation. This makes iris recognition systems unavoidable in emerging security & authentication mechanisms. An iris recognition sy...Iris recognition enjoys universality, high degree of uniqueness and moderate user co-operation. This makes iris recognition systems unavoidable in emerging security & authentication mechanisms. An iris recognition system based on vector quantization (VQ) techniques is proposed and its performance is compared with the discrete cosine transform (DCT). The proposed system does not need any pre-processing and segmentation of the iris. We have tested Linde-Buzo- Gray (LBG), Kekre's proportionate error (KPE) algorithm and Kekre's fast codebook generation (KFCG) algorithm for the clustering purpose. Proposed vector quantization based method using KFCG requires 99.99% less computations as that of full 2-dimensional DCT. Further, the KFCG method gives better performance with the accuracy of 89.10% outperforming DCT that gives accuracy around 66.10%.展开更多
The purpose of this study is to determine whether advancing age andheart failure are independent predictors of increased mortality afrer acutemyocardial infarction(AMI)We reviewed the clinical data of 1068 in-patients...The purpose of this study is to determine whether advancing age andheart failure are independent predictors of increased mortality afrer acutemyocardial infarction(AMI)We reviewed the clinical data of 1068 in-patients(344 senile/724 nonsenile)with AMI.The results showed atypicalpresentations of infarction-related symptoms in the elderly are common,with consequent delay in the diagnosis and treatment The elderly patientshad a high proportion of systemic hypertension(43.9%),non Q wave AM/(36%)and heart failure(35.5%),On the contrast,the proportion of that innonsenile patients were 33%,8Vo and 16.4% respectively.In elderlypatients,several complications:of AMI are more common,asinterventricular septum perforation(2%),cardiogenic shock(19.8%),arthythmia(61.9%).Heart failure was more frequent in patients with leftventricular ejection fraction(LVEF)≤35%,previous heart failure ormyocardial infarction,and anterior location infarction.Those with severecongestive heart failure had a mortality of 33.2% compared with 24.5% forthose with moderate heart failure and 13.51% for those with no heart failurein the first eight weeks.The following factors were associated with anincreased risk of death:older age,longer delay before admission to hospital,no prescription of beta-blaekers and a previous history of infarctionOur data suggested that the prognosis after AMI was directly related toadvaneeing age and the severity of congestive heart failure.Thedevelopment of congestive heart failure was an independent predictor ofdeath.The increasing incidence and mortality were closely related toimpaired myocardial reserve.The present benefits,as pointed out by therecent progress in AMI therapy,must be employed in the treatment of olderinfarcted patients More aggressive management in elderly patients shouldoe evaluated for its potential to reduce mortality.展开更多
文摘AIM To explore the relationship between collagen proportionate area(CPA) and portal hypertension-related clinical manifestations in alcoholic liver disease(ALD).METHODS Retrospective study with chart review of patients with ALD adressed to our center between January 2012 and December 2013 for a transjugular liver biopsy(TJLB) and hepatic hemodynamic study. Patients were included if they met the following criteria:(1) Medical indication for a liver biopsy in the setting of ALD;(2) recent(< 15 d) clinical, radiological, endoscopic and biological data available; and(3) estimated follow-up of at least 6 mo. Liver tissue from cirrhotic subjects obtained from transjugular liver biopsies was stained with Picro Sirius red and computer-assisted digital image analysis to determine fibrosis density using CPA was performed. RESULTS We included 61 patients with alcoholic ALD, subdivided in 41 active alcohol drinkers and 20 durably abstinent patients. Nine healthy liver donors served as controls. Mean CPA in patients with ALD was 7.1%, with no difference between active drinkers and abstinent patients(P = 0.17). Using a fibrosis density cutoff of 5%, we observed a positive correlation between high fibrosis density and the hepatic venous pressure gradient(HVPG) only in active drinkers(P = 0.02). At 12-mo of follow-up, in the group of active alcohol drinkers, patients reaching a composite outcome showed a higher HVPG value as compared to those who did not(18.5 mm Hg vs 14.5 mm Hg P < 0.04) whereas CPA values were similar(6.9% vs 11%, P = 0.23).CONCLUSION In active alcoholic ALD, CPA correlates to portal pressure but only HVPG predicts clinical events, pointing to the role of alcohol as a modulator of portal hypertension.
基金upported by a grant from the Technology and Plan of Guangdong Province, China (2009B030801006)
文摘BACKGROUND: The accurate assessment of the degree of hepatic fibrosis plays a critical role in guiding the diagnosis, treatment and prognostic assessment of chronic liver diseases. Liver biopsy is currently the most reliable method to evaluate the severity of hepatic fibrosis. However, liver biopsy is an invasive procedure associated with morbidity and mortality, and has several limitations in patients with decompensated cirrhosis. There is no report on the collagen proportionate area (CPA) of liver tissue in the decompensated stage of cirrhosis. This study aimed to determine the CPA of resected liver tissue samples from patients with HBV-related decompensated cirrhosis using digital image analysis, and to analyze the relationship between the CPA and liver functional reserve. METHODS: Fifty-three resected liver tissue samples from liver transplant patients with chronic hepatitis B-induced decompensated cirrhosis were stained with Masson’s trichrome, and the CPA in these samples was quantitatively determined using digital image analysis. The values of relevant liver function just before liver transplantation, the CPA in liver tissue, and their correlation were analyzed. RESULTS: The mean CPA at the decompensated stage of cirrhosis was 35.93±14.42% (11.24%-63.41%). The correlation coefficients of the CPA with a model for end-stage liver disease score, serum total bilirubin and international standard ratio of prothrombin B were 0.553, 0.519 and 0.533, respectively (P<0.001). With increasing CPA values, the three indices reflecting liver functional reserve also changed significantly.CONCLUSIONS: The degree of fibrosis may be correlated with the functional reserve. With the advancement of fibrosis, the liver functional reserve is attenuated accordingly.
文摘In this paper after analyzing the adaptation process of the proportionate normalized least mean square(PNLMS) algorithm, a statistical model is obtained to describe the convergence process of each adaptive filter coefcient. Inspired by this result, a modified PNLMS algorithm based on precise magnitude estimate is proposed. The simulation results indicate that in contrast to the traditional PNLMS algorithm, the proposed algorithm achieves faster convergence speed in the initial convergence state and lower misalignment in the stead stage with much less computational complexity.
基金funded by the National Natural Science Foundation of China(52077004)Anhui Electric Power Company of the State Grid(52120021N00L).
文摘Aiming at the problemthat the traditional short-circuit current calculationmethod is not applicable to Distributed Generation(DG)accessing the distribution network,the paper proposes a short-circuit current partitioning calculation method considering the degree of voltage drop at the grid-connected point of DG.Firstly,the output characteristics of DG in the process of low voltage ride through are analyzed,and the equivalent output model of DG in the fault state is obtained.Secondly,by studying the network voltage distribution law after fault in distribution networks under different DG penetration rates,the degree of voltage drop at the grid-connected point of DG is used as a partition index to partition the distribution network.Then,iterative computation is performed within each partition,and data are transferred between partitions through split nodes to realize the fast partition calculation of short-circuit current for high proportion DG access to distribution network,which solves the problems of long iteration time and large calculation error of traditional short-circuit current.Finally,a 62-node real distribution network model containing a high proportion of DG access is constructed onMATLAB/Simulink,and the simulation verifies the effectiveness of the short-circuit current partitioning calculation method proposed in the paper,and its calculation speed is improved by 48.35%compared with the global iteration method.
文摘Sample size determination typically relies on a power analysis based on a frequentist conditional approach. This latter can be seen as a particular case of the two-priors approach, which allows to build four distinct power functions to select the optimal sample size. We revise this approach when the focus is on testing a single binomial proportion. We consider exact methods and introduce a conservative criterion to account for the typical non-monotonic behavior of the power functions, when dealing with discrete data. The main purpose of this paper is to present a Shiny App providing a user-friendly, interactive tool to apply these criteria. The app also provides specific tools to elicit the analysis and the design prior distributions, which are the core of the two-priors approach.
文摘为提升船用汽轮发电机组大幅变工况时的控制精度和鲁棒性,以船用汽轮机调节系统各部件的模块化数学模型为基础,建立汽轮机组数字电液(digital electric hydraulic,DEH)闭环模糊比例、积分、微分(proportion integration derivative,PID)控制模型;融合遗传算法的选择、交叉、变异和自适应递减权重法,提出遗传粒子群智能优化算法,并结合标准测试函数验证提出算法具有较高的收敛速度和精度;基于遗传粒子群智能优化算法建立汽轮机变工况自适应智能模糊PID控制模型,实现模糊PID的量化因子与比例因子最优化设计,进而开展船用汽轮发电机组大幅变工况动态特性及扰动因素影响分析,结果表明本文建立的自适应智能模糊PID控制模型具有更好的控制稳态性能与鲁棒性,为船用汽轮机组大幅度变工况智能控制优化设计提供了有力的技术支撑。
基金This work was financially supported by the National Natural Science Foundation of China(No.52074041)the Chongqing Talent Program(No.cstc2022ycjh-bgzxm0077)the Postgraduate Research and Innovation Foundation of Chongqing,China(No.CYS23060).
文摘In coal mining,rock strata are fractured under cyclic loading and unloading to form fracture channels.Fracture channels are the main flow narrows for gas.Therefore,expounding the flow conductivity of fracture channels in rocks on fluids is significant for gas flow in rock strata.In this regard,graded incremental cyclic loading and unloading experiments were conducted on sandstones with different initial stress levels.Then,the three-dimensional models for fracture channels in sandstones were established.Finally,the fracture channel percentages were used to reflect the flow conductivity of fracture channels.The study revealed how the particle size distribution of fractured sandstone affects the formation and expansion of fracture channels.It was found that a smaller proportion of large blocks and a higher proportion of small blocks after sandstone fails contribute more to the formation of fracture channels.The proportion of fracture channels in fractured rock can indicate the flow conductivity of those channels.When the proportion of fracture channels varies gently,fluids flow evenly through those channels.However,if the proportion of fracture channels varies significantly,it can greatly affect the flow rate of fluids.The research results contribute to revealing the morphological evolution and flow conductivity of fracture channels in sandstone and then provide a theoretical basis for clarifying the gas flow pattern in the rock strata of coal mines.
基金financially supported by the National Key Research and Development Program of China (Nos.2018YFC1900603 and 2018YFC0604604)。
文摘The development of solid waste resources as constituent materials for wet shotcrete has significant economic and environmental advantages. In this study, the concept of using tailings as aggregate and fly ash and slag powder as auxiliary cementitious material is proposed and experiments are carried out by response surface methodology(RSM). Multivariate nonlinear response models are constructed to investigate the effect of factors on the uniaxial compressive strength(UCS) of tailings wet shotcrete(TWSC). The UCS of TWSC is predicted and optimized by constructing Gaussian process regression(GPR) and genetic algorithm(GA). The UCS of TWSC is gradually enhanced with the increase of slag powder dosage and fineness modulus, and it is enhanced first and then decreased with the increase of fly ash dosage. The microstructure of TWSC has the highest gray value and the highest UCS when the fly ash dosage is about 120 kg·m^(-3). The GPR–GA model constructed in this study achieves high accuracy prediction and optimization of the UCS of TWSC under multi-factor conditions.
基金Funded by the Key Research and Development Projects in Shaanxi Province(No.2022SF-328)Science and Technology Project of Shaanxi Department of Transportation(Nos.19-10K,19-28K)Science and Technology Project of Henan Department of Transportation(No.2020J-2-3)。
文摘In order to comprehensively utilize the remaining bamboo residue of bamboo products,this paper presents a research on recycling the bamboo fibers from bamboo residue for improving the performance of the asphalt mixtures.First of all,the basic performance parameters of sinocalamus affinis fiber,phyllostachys pubescens fiber,green bamboo fiber were tested and analyzed,and the optimal content and length were put forward.Then,the mix ratio design of the bamboo fiber modified asphalt mixture was further designed through the response surface method,and was verified the rationality of the mix ratio.Finally,the mixture specimens were made according to the experimental design mix ratio,and the high temperature,low temperature performance and moisture susceptibility of the bamboo fiber modified mixtures asphalt were tested.The results showed that the high temperature performance,low temperature performance and moisture susceptibility of bamboo fiber modified asphalt mixtures were improved compared with the performance of SBS modified asphalt mixture.When the length of bamboo fiber is 7.25 mm and the content of 0.22%,the road performance of the asphalt mixture was optimal.Consequentially,the decomposition of bamboo residue into bamboo fiber and its application in asphalt pavement can improve the reuse of bamboo waste,with remarkable environmental benefits and great promotion value.
基金This work is funded by the National Key Research and Development Program of China(Grant Nos.2018YFC1900603,2018YFC0604604).
文摘Tailings known as solid waste are generated by the mining industry.The development of tailings as wet shotcrete aggregates has significant economic and environmental benefits.The fine particle size of the tailings results in a large consumption of traditional cement as a cementitious material and insignificant improvement in strength.Therefore,a composite cementitious system of cement and solid waste resources(fly ash and slag powder)is explored for this study.In this paper,the response surface methodology(RSM)is used to optimize the experimental design and a multivariate nonlinear response model with cement,fly ash and slag powder contents as variables are constructed,which can investigate the effect of the composite cementitious system on the strength of tailing wet shotcrete(TWSC).In addition,the information entropy(IE)is introduced and combined with the RSM to evaluate the composite cementitious system.Finally,the desirability function(DF)combined with RSM is used to optimize the composite cementitious system.The results show that the response model constructed in this paper has R^(2)=0.96 and P-value<0.01(the test result of the model is P-value<0.01),which indicates that the model has high reliability.The higher the content of slag powder and cement in the composite cementitious system,the higher the strength and comprehensive score of the TWSC.There is a critical value of fly ash content,which makes the maximum cementation of the composite cementing system.The optimal mix proportion of the composite cementitious system is obtained based on RSM-DF,which leads to the strength of TWSC at different curing time to achieve the expected index.
基金Civil Project of China Aerospace Science and Technology CorporationUniversity-Industry Collaborative Education Program of Ministry of Education of China(No.220906517214433)。
文摘Aiming at solving the problems of response lag and lack of precision and stability in constant grinding force control of industrial robot belts,a constant force control strategy combining fuzzy control and proportion integration differentiation(PID)was proposed by analyzing the signal transmission process and the dynamic characteristics of the grinding mechanism.The simulation results showed that compared with the classical PID control strategy,the system adjustment time was shortened by 98.7%,the overshoot was reduced by 5.1%,and the control error was 0.2%-0.5%when the system was stabilized.The optimized fuzzy control system had fast adjustment speeds,precise force control and stability.The experimental analysis of the surface morphology of the machined blade was carried out by the industrial robot abrasive grinding mechanism,and the correctness of the theoretical analysis and the effectiveness of the control strategy were verified.
文摘In this paper,based on the process data of evaluating the benchmark land prices of collective construction land and agricultural land,the score of influencing factors is calculated,and a regression model between value-added benefits and influencing factors is established.According to the contribution of the government and collectives to value-added benefits,the distribution proportions of different purposes and levels are calculated.The research results show that there are significant differences in the distribution proportion of value-added income among different levels.The government distribution proportion decreases with the decrease of level,while the collective distribution proportion increases with the decrease of level.For each level of decrease in commercial service industry land and industrial and mining warehousing industry land,the government distribution proportion decreases by an average of 2.66%and 2.34%,while the collective distribution proportion increases by an average of 2.66%and 2.34%,respectively.The average distribution proportion of the government in the value-added income of commercial service industry land is 31.58%,which is much higher than the average income of 23.68%in the value-added income of industrial and mining warehousing industry land.
文摘BACKGROUND Cancer diagnosis is increasing around the world and in the Democratic Republic of the Congo(DRC).The proportion of thyroid cancer has increased over the past three decades.There are very few studies on cancer epidemiology,and in particular on thyroid cancer in the DRC.AIM To establish the most recent proportion of thyroid cancer in the DRC compared to other cancers.METHODS This is a retrospective and descriptive study of 6106 consecutive cancer cases listed in the pathological registers of 4 Laboratories in the city of Kinshasa.This study included all cancer cases recorded in the registers between 2005 and 2019.RESULTS From a sample of 6106 patients,including all cancer types,68.3%cases were female and 31.7%were male.Breast and cervical cancer were the most common types of cancer in women and,prostate and skin cancer were the most common types in men.Thyroid cancer was sixth in proportion in women and eleventh in men compared to all cancers.Papillary carcinoma was the most common of thyroid cancers.Rare cancers such as anaplastic and medullary thyroid carcinomas had a proportion of 7%and 2%,respectively.CONCLUSION Newer diagnostic tools led to a surge in cancer diagnoses in the DRC.Thyroid cancer has more than doubled its proportion over the last several decades in the country.
文摘A multi-qubit pure quantum state is called separable when it can be factored as the tensor product of 1-qubit pure quantum states.Factorizing a general multi-qubit pure quantum state into the tensor product of its factors(pure states containing a smaller number of qubits)can be a challenging task,especially for highly entangled states.A new criterion based on the proportionality of the rows of certain associated matrices for the existence of certain factorization and a factorization algorithm that follows from this criterion for systematically extracting all the factors is developed in this paper.3-qubit pure states play a crucial role in quantum computing and quantum information processing.For various applications,the well-known 3-qubit GHZ state which contains two nonzero terms,and the 3-qubit W state which contains three nonzero terms,have been studied extensively.Using the new factorization algorithm developed here we perform a complete analysis vis-à-vis entanglement of 3-qubit states that contain exactly two nonzero terms and exactly three nonzero terms.
文摘汽车悬架控制系统是一个由较多非线性因素共同作用的复杂系统,针对传统PID控制效果不理想的问题,通过数值拟合的方式引入弹簧与阻尼等非线性影响因素,建立1/4汽车悬架非线性动力学模型,借鉴免疫反馈原理,结合积分控制的规律,提出一种模糊免疫PID(proportion integral derivative)控制方法,并利用免疫进化算法进行参数优化设计。仿真结果表明,该方法在汽车非线性悬架控制系统中可行且有效,其控制器性能也优于常规的PID控制器,具有更好的响应特性,同时也提高了汽车的操作稳定性和乘坐舒适性。
文摘Iris recognition enjoys universality, high degree of uniqueness and moderate user co-operation. This makes iris recognition systems unavoidable in emerging security & authentication mechanisms. An iris recognition system based on vector quantization (VQ) techniques is proposed and its performance is compared with the discrete cosine transform (DCT). The proposed system does not need any pre-processing and segmentation of the iris. We have tested Linde-Buzo- Gray (LBG), Kekre's proportionate error (KPE) algorithm and Kekre's fast codebook generation (KFCG) algorithm for the clustering purpose. Proposed vector quantization based method using KFCG requires 99.99% less computations as that of full 2-dimensional DCT. Further, the KFCG method gives better performance with the accuracy of 89.10% outperforming DCT that gives accuracy around 66.10%.
文摘The purpose of this study is to determine whether advancing age andheart failure are independent predictors of increased mortality afrer acutemyocardial infarction(AMI)We reviewed the clinical data of 1068 in-patients(344 senile/724 nonsenile)with AMI.The results showed atypicalpresentations of infarction-related symptoms in the elderly are common,with consequent delay in the diagnosis and treatment The elderly patientshad a high proportion of systemic hypertension(43.9%),non Q wave AM/(36%)and heart failure(35.5%),On the contrast,the proportion of that innonsenile patients were 33%,8Vo and 16.4% respectively.In elderlypatients,several complications:of AMI are more common,asinterventricular septum perforation(2%),cardiogenic shock(19.8%),arthythmia(61.9%).Heart failure was more frequent in patients with leftventricular ejection fraction(LVEF)≤35%,previous heart failure ormyocardial infarction,and anterior location infarction.Those with severecongestive heart failure had a mortality of 33.2% compared with 24.5% forthose with moderate heart failure and 13.51% for those with no heart failurein the first eight weeks.The following factors were associated with anincreased risk of death:older age,longer delay before admission to hospital,no prescription of beta-blaekers and a previous history of infarctionOur data suggested that the prognosis after AMI was directly related toadvaneeing age and the severity of congestive heart failure.Thedevelopment of congestive heart failure was an independent predictor ofdeath.The increasing incidence and mortality were closely related toimpaired myocardial reserve.The present benefits,as pointed out by therecent progress in AMI therapy,must be employed in the treatment of olderinfarcted patients More aggressive management in elderly patients shouldoe evaluated for its potential to reduce mortality.