To utilize heat and electricity in a clean and integrated manner,a zero-carbon-emission micro Energy Internet(ZCE-MEI) architecture is proposed by incorporating non-supplementary fired compressed air energy storage(NS...To utilize heat and electricity in a clean and integrated manner,a zero-carbon-emission micro Energy Internet(ZCE-MEI) architecture is proposed by incorporating non-supplementary fired compressed air energy storage(NSF-CAES) hub.A typical ZCE-MEI combining power distribution network(PDN) and district heating network(DHN) with NSF-CAES is considered in this paper.NSF-CAES hub is formulated to take the thermal dynamic and pressure behavior into account to enhance dispatch flexibility.A modified Dist Flow model is utilized to allow several discrete and continuous reactive power compensators to maintain voltage quality of PDN.Optimal operation of the ZCE-MEI is firstly modeled as a mixed integer nonlinear programming(MINLP).Several transformations and simplifications are taken to convert the problem as a mixed integer linear programming(MILP)which can be effectively solved by CPLEX.A typical test system composed of a NSF-CAES hub,a 33-bus PDN,and an 8-node DHN is adopted to verify the effectiveness of the proposed ZCE-MEI in terms of reducing operation cost and wind curtailment.展开更多
When evaluating the track fusion algorithm,common accuracy indexes may fail to evaluate the fusion accuracy correctly when the state estimation and the real target cannot be one-to-one,and fail to effectively distingu...When evaluating the track fusion algorithm,common accuracy indexes may fail to evaluate the fusion accuracy correctly when the state estimation and the real target cannot be one-to-one,and fail to effectively distinguish the performance of the algorithm when the state estimation is similar.Therefore,it is necessary to construct a high-resolution evaluation index,which can evaluate the track fusion algorithm more accurately,reasonably and comprehensively.Firstly,the advant ages and disadvantages of the optimal subpattern assignment(OSPA)dis tance as the accuracy index to evaluate the track fusion algorithm are analyzed.Then,its deficiencies are improved by using the Hellinger distance instead of the original Euclidean distance,and the distance is index transformed.Finally,a new evaluation index for track fusion algorithms is proposed,which is the OSPA distance based on Hellinger distance and index transformation.The simulation results show that the new index can not only correctly evaluate the fusion precision,but also consider the state uncertainty,making that can evaluate the track fusion algorithm more sensitively,and effectively solves the sensitivity of the index to the cut-off parameter c through index transformation.展开更多
Controller area network(CAN) is a widely used fieldbus protocol in various industrial applications.To understand the network behavior under errors for the optimal design of networked control systems, the message respo...Controller area network(CAN) is a widely used fieldbus protocol in various industrial applications.To understand the network behavior under errors for the optimal design of networked control systems, the message response time of the CAN network needs to be analyzed. In this study, a novel delay time distribution analysis method for the response messages is proposed when considering errors. In this method the complex message queues are decomposed into typical message patterns and cases. First, a stochastic fault model is developed, and the probability factor is defined to calculate the error distribution. Then the message delay time distribution for the single slave node configuration is analyzed based on the error distribution. Next, based on the delay time distribution analysis of typical patterns and cases, an analysis framework of message delay time distribution for the master/slave configuration is developed. The testbed is constructed and case studies are conducted to demonstrate the proposed methodology under different network configurations. Experimental results show that the delay time distributions calculated by the proposed method agree well with the actual observations.展开更多
The Upper Cretaceous(early Cenomanian)Bahariya Formation of Egypt has an outstanding reputation for its wealth of vertebrate remains,including a variety of iconic dinosaurs,like the carnivorous Spinosaurus and Carchar...The Upper Cretaceous(early Cenomanian)Bahariya Formation of Egypt has an outstanding reputation for its wealth of vertebrate remains,including a variety of iconic dinosaurs,like the carnivorous Spinosaurus and Carcharodontosaurus,as well as the herbivorous Aegyptosaurus and Paralititan.Besides these dinosaur fossils,the Bahariya Formation yielded also a wealth of invertebrate and plant remains,but even today many aspects concerning the continental palaeoenvironments reflected in these deposits(including the occurrence of palaeo-wildfires)have not been studied in detail.So far six distinct macro-charcoal bearing levels could be identified within the type section of the Bahariya Formation at Gabal El Dist profile,one of the most prolific outcrops of this formation in terms of fossil occurrence located in the north of the Bahariya Oasis,Western Desert,Egypt.Most of the charcoal investigated by means of SEM originates from ferns,pointing to a considerable proportion of this plant group within the palaeo-ecosystems that experienced fires.Gymnosperms and(putative)angiosperms have less frequently been identified.The collected data present evidence that the landscapes at the northern shores of Gondwana repeatedly experienced palaeo-wildfires,adding extra proof to previous statements that the Late Cretaceous was a fiery world on a global scale.展开更多
In this article, we consider the non-linear difference equation(f(z + 1)f(z)-1)(f(z)f(z-1)-1) =P(z, f(z))/Q(z, f(z)),where P(z, f(z)) and Q(z, f(z)) are relatively prime polynomials in f(z) with rational coefficients....In this article, we consider the non-linear difference equation(f(z + 1)f(z)-1)(f(z)f(z-1)-1) =P(z, f(z))/Q(z, f(z)),where P(z, f(z)) and Q(z, f(z)) are relatively prime polynomials in f(z) with rational coefficients. For the above equation, the order of growth, the exponents of convergence of zeros and poles of its transcendental meromorphic solution f(z), and the exponents of convergence of poles of difference △f(z) and divided difference △f(z)/f(z)are estimated. Furthermore, we study the forms of rational solutions of the above equation.展开更多
Lianyungang city will see construction start on a 800,000-ton copper smelting and copper products processing. During Phase I of the project, 400,000-tons of refined copper and 1.
Let Ω CR^d,1≤d≤3, be a bounded d-polytope. Consider the parabolic equation on Q with the Dirac delta function on the right hand side. We study the well-posedness, regularity, and the interior error estimate of semi...Let Ω CR^d,1≤d≤3, be a bounded d-polytope. Consider the parabolic equation on Q with the Dirac delta function on the right hand side. We study the well-posedness, regularity, and the interior error estimate of semidiscrete finite element approximations of the equation. In particular, we derive that the interior error is bounded by the best local approximation error, the negative norms of the error, and the negative norms of the time derivative of the error. This result implies different convergence rates for the numerical solution in different interior regions, especially when the region is close to the singular point. Numerical test results are reported to support the theoretical prediction.展开更多
基金supported in part by the National Natural Science Foundation of China(No.51321005,No.51377092,No.51577163)Opening Foundation of the Qinghai Province Key Laboratory of Photovoltaic Power Generation and Grid-connected Technology
文摘To utilize heat and electricity in a clean and integrated manner,a zero-carbon-emission micro Energy Internet(ZCE-MEI) architecture is proposed by incorporating non-supplementary fired compressed air energy storage(NSF-CAES) hub.A typical ZCE-MEI combining power distribution network(PDN) and district heating network(DHN) with NSF-CAES is considered in this paper.NSF-CAES hub is formulated to take the thermal dynamic and pressure behavior into account to enhance dispatch flexibility.A modified Dist Flow model is utilized to allow several discrete and continuous reactive power compensators to maintain voltage quality of PDN.Optimal operation of the ZCE-MEI is firstly modeled as a mixed integer nonlinear programming(MINLP).Several transformations and simplifications are taken to convert the problem as a mixed integer linear programming(MILP)which can be effectively solved by CPLEX.A typical test system composed of a NSF-CAES hub,a 33-bus PDN,and an 8-node DHN is adopted to verify the effectiveness of the proposed ZCE-MEI in terms of reducing operation cost and wind curtailment.
基金the Natural Science Foundation of Hebei Province(No.F2017506006)。
文摘When evaluating the track fusion algorithm,common accuracy indexes may fail to evaluate the fusion accuracy correctly when the state estimation and the real target cannot be one-to-one,and fail to effectively distinguish the performance of the algorithm when the state estimation is similar.Therefore,it is necessary to construct a high-resolution evaluation index,which can evaluate the track fusion algorithm more accurately,reasonably and comprehensively.Firstly,the advant ages and disadvantages of the optimal subpattern assignment(OSPA)dis tance as the accuracy index to evaluate the track fusion algorithm are analyzed.Then,its deficiencies are improved by using the Hellinger distance instead of the original Euclidean distance,and the distance is index transformed.Finally,a new evaluation index for track fusion algorithms is proposed,which is the OSPA distance based on Hellinger distance and index transformation.The simulation results show that the new index can not only correctly evaluate the fusion precision,but also consider the state uncertainty,making that can evaluate the track fusion algorithm more sensitively,and effectively solves the sensitivity of the index to the cut-off parameter c through index transformation.
基金the National Natural Science Foundation of China (Nos. 51475422 and 51521064).
文摘Controller area network(CAN) is a widely used fieldbus protocol in various industrial applications.To understand the network behavior under errors for the optimal design of networked control systems, the message response time of the CAN network needs to be analyzed. In this study, a novel delay time distribution analysis method for the response messages is proposed when considering errors. In this method the complex message queues are decomposed into typical message patterns and cases. First, a stochastic fault model is developed, and the probability factor is defined to calculate the error distribution. Then the message delay time distribution for the single slave node configuration is analyzed based on the error distribution. Next, based on the delay time distribution analysis of typical patterns and cases, an analysis framework of message delay time distribution for the master/slave configuration is developed. The testbed is constructed and case studies are conducted to demonstrate the proposed methodology under different network configurations. Experimental results show that the delay time distributions calculated by the proposed method agree well with the actual observations.
基金support by Coordenadoria de Aperfeicoamento de Pessoal de Nível Superior-CAPES(A072/2013 and 8107-14-9)Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq(444330/2014-3,305436/2015-5)Brazil and Alexander von Humboldt Foundation(3.4-8151/18 025),Germany
文摘The Upper Cretaceous(early Cenomanian)Bahariya Formation of Egypt has an outstanding reputation for its wealth of vertebrate remains,including a variety of iconic dinosaurs,like the carnivorous Spinosaurus and Carcharodontosaurus,as well as the herbivorous Aegyptosaurus and Paralititan.Besides these dinosaur fossils,the Bahariya Formation yielded also a wealth of invertebrate and plant remains,but even today many aspects concerning the continental palaeoenvironments reflected in these deposits(including the occurrence of palaeo-wildfires)have not been studied in detail.So far six distinct macro-charcoal bearing levels could be identified within the type section of the Bahariya Formation at Gabal El Dist profile,one of the most prolific outcrops of this formation in terms of fossil occurrence located in the north of the Bahariya Oasis,Western Desert,Egypt.Most of the charcoal investigated by means of SEM originates from ferns,pointing to a considerable proportion of this plant group within the palaeo-ecosystems that experienced fires.Gymnosperms and(putative)angiosperms have less frequently been identified.The collected data present evidence that the landscapes at the northern shores of Gondwana repeatedly experienced palaeo-wildfires,adding extra proof to previous statements that the Late Cretaceous was a fiery world on a global scale.
基金supported by the National Natural Science Foundation of China(11371225)National Natural Science Foundation of Guangdong Province(2016A030313686)
文摘In this article, we consider the non-linear difference equation(f(z + 1)f(z)-1)(f(z)f(z-1)-1) =P(z, f(z))/Q(z, f(z)),where P(z, f(z)) and Q(z, f(z)) are relatively prime polynomials in f(z) with rational coefficients. For the above equation, the order of growth, the exponents of convergence of zeros and poles of its transcendental meromorphic solution f(z), and the exponents of convergence of poles of difference △f(z) and divided difference △f(z)/f(z)are estimated. Furthermore, we study the forms of rational solutions of the above equation.
文摘Lianyungang city will see construction start on a 800,000-ton copper smelting and copper products processing. During Phase I of the project, 400,000-tons of refined copper and 1.
基金Li Guo was supported in part by the National Natural Science Foundation of China under the grant 11601536.Hengguang Li was supported in part by the National Science Foundation Grant DMS-1418853,by the Natural Science Foundation of China Grant 11628104,and by the Wayne State University Grants Plus Program.Yang Yang was supported in part by the National Natural Science Foundation of China under the grants 11571367&11601536 and the Fundamental Research Funds for the Central Universities 18CX05003A.
文摘Let Ω CR^d,1≤d≤3, be a bounded d-polytope. Consider the parabolic equation on Q with the Dirac delta function on the right hand side. We study the well-posedness, regularity, and the interior error estimate of semidiscrete finite element approximations of the equation. In particular, we derive that the interior error is bounded by the best local approximation error, the negative norms of the error, and the negative norms of the time derivative of the error. This result implies different convergence rates for the numerical solution in different interior regions, especially when the region is close to the singular point. Numerical test results are reported to support the theoretical prediction.
文摘为实现对瓦斯浓度(体积分数)的准确预测,基于海量煤矿瓦斯监测数据和多元分布滞后模型(MDL)建立了多变量瓦斯浓度时间序列预测模型.基于惩罚最小二乘法和自回归的思想,提出了新的变量选择和定阶方法——Adjust Group最小绝对值压缩与选择(LASSO)方法.该方法以岭估计及局部二次近似迭代算法实现了预测模型的构建,通过有效选取具有解释性的自变量子集,提高模型的解释性,采用广义交叉检验准则(GCV)确定惩罚参数,并通过分组惩罚来实现变量筛选与滞后变量的定阶.结果表明:Adjust Group LASSO方法预测得到的残差平方和为0.433 0,具有较高的精度,能够较好的预测工作面瓦斯浓度的动态变化,与LASSO、最小角回归算法(LARS)以及其他瓦斯预测常用方法相比,大大提高了预测的准确性.
