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An Optimal DASH Diet Model for People with Hypertension Using Linear Programming Approach 被引量:1
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作者 Anayo Charles Iwuji Mercy Nnanna Nonso Ifeyinwa C. Ndulue 《Open Journal of Optimization》 2016年第1期14-21,共8页
Selecting diets by quantitative techniques is becoming increasingly common. Linear programming is the most popular technique for the selection of least cost mixes of food to meet specific nutritional requirements for ... Selecting diets by quantitative techniques is becoming increasingly common. Linear programming is the most popular technique for the selection of least cost mixes of food to meet specific nutritional requirements for a particular group of persons for either general health or disease-related reason. Hypertension is a silent killer and its prevalence rate especially in the developing countries, which has been mostly associated to demographic, environmental and genetic factors, is becoming alarming. The DASH diet has been clinically proven to prevent and control hypertension. In this paper, a model that provides a Daily Optimal (minimum cost) DASH Diet plan for people with hypertension is formulated. The objective is to obtain daily minimum cost diet plans that satisfy the DASH Diets’ nutrients Tolerable Upper and Lower Intake for different daily Calorie Levels. The formulated DASH diet model was further illustrated using real data set with food samples gotten from the DASH eating plan chart. A DASH diet model for a hypertensive person with a 2000-daily-caloric need was formulated and its optimal diet plan for a day obtained with a total cost of 944.41 Naira. Optimal diet plans for other recommended daily calorie levels were also obtained. 展开更多
关键词 DASH (Dietary approaches to Stop Hypertension) HYPERTENSION Minimum Cost Diet Plan linear Programming Diet Problem
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Two-Phase Multi Objective Fuzzy Linear Programming Approach for Sustainable Irrigation Planning
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作者 D. G. Regulwar Jyotiba B. Gurav 《Journal of Water Resource and Protection》 2013年第6期642-651,共10页
The objective of the present study is to develop the irrigation planning model and to apply the same in the form of Two-Phase Multi Objective Fuzzy Linear Programming (TPMOFLP) approach for crop planning in command ar... The objective of the present study is to develop the irrigation planning model and to apply the same in the form of Two-Phase Multi Objective Fuzzy Linear Programming (TPMOFLP) approach for crop planning in command area of Jayakwadi Project Stage I, Maharashtra State, India. The development of TPMOFLP model is on the basis of various Linear Programming (LP) models and Multi Objective Fuzzy Linear Programming (MOFLP) models, these models have been applied for maximization of the Net Benefits (NB), Crop production (CP), Employment Generation (EG) and Manure Utilization (MU) respectively. The significant increase in the value of level of satisfaction (λ) has been found from 0.58 to 0.65 by using the TPMOFLP approach as compare to that of MOFLP model based on maxmin approach. The two-phase approach solution provides NB = 1503.56 Million Rupees, CP = 335729.30 Tons, EG = 29.74 Million Man days and MU = 160233.70 Tons respectively. The proposed model will be helpful for the Decision Maker (DM) to take a decision under conflicting situation while planning for different conflicting objectives simultaneously and has potential to find out an integrated irrigation planning with prime consideration for economic, social and environmental issue. 展开更多
关键词 SUSTAINABLE IRRIGATION PLANNING Multi Objective Fuzzy linear PROGRAMMING Maxmin approach TWO-PHASE approach
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Observer design for matrix second order linear systems with uncertain disturbance input-a parametric approach
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作者 Wu Yunli Li Zhibin Duan Cruangren 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第4期811-816,823,共7页
A simple parametric approach to design a full-order observer for matrix second-order linear systems with uncertain disturbance input in the matrixsecond-order framework is proposed. The basic idea is to minimize the H... A simple parametric approach to design a full-order observer for matrix second-order linear systems with uncertain disturbance input in the matrixsecond-order framework is proposed. The basic idea is to minimize the H2 norm of the transfer function from disturbance to estimation error using the design degrees of freedom provided by a parametric approach in the observer design. Besides the design parameters, the eigenvalues of the closed-loop system are also optimized within desired regions on the left-half of the complex plane. Using the proposed approach, additional specifications can be easily achieved. A spring-mass system is using to show the effect of the proposed approaches. 展开更多
关键词 linear systems uncertain disturbance input observers parametric approach optimization.
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A mixed integer linear programming approach for municipal solid waste management
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《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1997年第4期49-63,共15页
AmixedintegerlinearprogrammingapproachformunicipalsolidwastemanagementGordonGuoHeHuangEnvironmentalSystemsEn... AmixedintegerlinearprogrammingapproachformunicipalsolidwastemanagementGordonGuoHeHuangEnvironmentalSystemsEngineering,Univer... 展开更多
关键词 A mixed integer linear programming approach for municipal solid waste management
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Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach
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作者 Yi Yu Guo-Ping Liu +1 位作者 Yi Huang Peng Shi 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第2期405-417,共13页
DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately por... DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method. 展开更多
关键词 DC microgrids distributed control high-order fully actuated system approach linear quadratic regulator microgrid modeling secondary control
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High Order IMEX Stochastic Galerkin Schemes for Linear Transport Equation with Random Inputs and Diffusive Scalings
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作者 Zheng Chen Lin Mu 《Communications on Applied Mathematics and Computation》 EI 2024年第1期325-339,共15页
In this paper,we consider the high order method for solving the linear transport equations under diffusive scaling and with random inputs.To tackle the randomness in the problem,the stochastic Galerkin method of the g... In this paper,we consider the high order method for solving the linear transport equations under diffusive scaling and with random inputs.To tackle the randomness in the problem,the stochastic Galerkin method of the generalized polynomial chaos approach has been employed.Besides,the high order implicit-explicit scheme under the micro-macro decomposition framework and the discontinuous Galerkin method have been employed.We provide several numerical experiments to validate the accuracy and the stochastic asymptotic-preserving property. 展开更多
关键词 Stochastic Galerkin scheme linear transport equations generalized polynomial approach stochastic asymptotic-preserving property
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Probabilistic Robust Linear Parameter-varying Control of a Small Helicopter Using Iterative Scenario Approach
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作者 Zhou Fang Hua Tian Ping Li 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI 2015年第1期85-93,共9页
In this paper, we present an iterative scenario approach (ISA) to design robust controllers for complex linear parameter-varying (LPV) systems with uncertainties. The robust controller synthesis problem is transformed... In this paper, we present an iterative scenario approach (ISA) to design robust controllers for complex linear parameter-varying (LPV) systems with uncertainties. The robust controller synthesis problem is transformed to a scenario design problem, with the scenarios generated by identically extracting random samples on both uncertainty parameters and scheduling parameters. An iterative scheme based on the maximum volume ellipsoid cutting-plane method is used to solve the problem. Heuristic logic based on relevance ratio ranking is used to prune the redundant constraints, and thus, to improve the numerical stability of the algorithm. And further, a batching technique is presented to remarkably enhance the computational efficiency. The proposed method is applied to design an output-feedback controller for a small helicopter. Multiple uncertain physical parameters are considered, and simulation studies show that the closed-loop performance is quite good in both aspects of model tracking and dynamic decoupling. For robust LPV control problems, the proposed method is more computationally efficient than the popular stochastic ellipsoid methods. © 2014 Chinese Association of Automation. 展开更多
关键词 Aircraft control Algorithms Computation theory Computational efficiency Controllers Design Helicopters Optimization Problem solving Robust control Scheduling Stochastic systems Uncertainty analysis
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Airway management of a patient with linear immunoglobulin A bullous dermatosis:A case report
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作者 Olga C Nin Robert Hutnik +1 位作者 Neil N Chheda David Hutchinson 《World Journal of Clinical Cases》 SCIE 2024年第13期2263-2268,共6页
BACKGROUND There is limited literature on managing the airway of patients with linear immunoglobulin A(IgA)bullous dermatosis,a rare mucocutaneous disorder that leads to the development of friable bullae.Careful clini... BACKGROUND There is limited literature on managing the airway of patients with linear immunoglobulin A(IgA)bullous dermatosis,a rare mucocutaneous disorder that leads to the development of friable bullae.Careful clinical decision making is necessary when there is a risk of bleeding into the airway,and a multidisciplinary team approach may lead to decreased patient morbidity during these high-risk scenarios,especially when confronted with an unusual cause for bleeding.CASE SUMMARY A 45-year-old African American female presented to our ambulatory surgical center for right corneal transplantation due to corneal perforation after blunt trauma in the setting of cicatricial conjunctivitis and diffuse corneal neovascularization from linear IgA bullous dermatosis.The diagnosis of IgA dermatosis was recent,and the patient had been lost to follow-up.The severity of the disease and extent of airway involvement was unknown at the time of the surgery.Significant airway bleeding was noticed upon intubation and the otorhinolaryngology team had to be called to the operating room.The patient required transfer to the intensive care unit where a multidisciplinary team was involved in her case.The patient was extubated on postoperative day 4.CONCLUSION A multidisciplinary approach to treating this disease is the best course of action before a surgical procedure.In our case,key communication between the surgery,anesthesia,and dermatology teams led to the quick and safe treatment of our patient’s disease.Ambulatory surgery should not be considered for these cases unless they are in full remission and there is no mucous membrane involvement. 展开更多
关键词 Airway management Bleeding risk linear immunoglobulin A bullous dermatosis Multidisciplinary approach Outpatient procedure Case report
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一种针对^(90)Y的淬灭指数及其在^(90)Sr分析中的新应用
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作者 冯孝贵 袁建华 +4 位作者 何千舸 靳小军 孔雪艳 王建晨 陈靖 《核化学与放射化学》 北大核心 2025年第3期259-266,共8页
采用自定义的、针对^(90)Y的淬灭指数qx,结合改进双窗法,建立了一种用液闪仪(有时需要辅以γ谱仪)分析^(90)Sr的方法。使用该方法的前提有两点:(1)样品的淬灭水平较低,^(90)Sr或^(90)Y在全谱范围内的计数效率可以近似为100%;(2)^(90)Y... 采用自定义的、针对^(90)Y的淬灭指数qx,结合改进双窗法,建立了一种用液闪仪(有时需要辅以γ谱仪)分析^(90)Sr的方法。使用该方法的前提有两点:(1)样品的淬灭水平较低,^(90)Sr或^(90)Y在全谱范围内的计数效率可以近似为100%;(2)^(90)Y液闪谱图高能部分没有其它β核素的干扰。以高放废液分离热实验的三类真实样品为例,说明了该方法的具体使用步骤。实验采用的样品已达到^(90)Sr/^(90)Y放射性衰变平衡,因此可以用三种思路计算^(90)Sr含量,彼此相互验证。结果表明,用本方法得到的^(90)Sr含量是准确可靠的。本方法只需要对液闪谱图高能部分进行线性拟合,简单、易于操作,使用者可以根据待测样品的特点及分析要求,按应用建议选择合适的分析策略。对于^(90)Sr/^(90)Y样品(可含^(137)Cs),如果^(90)Sr的计数率占比不是太低,用本方法对^(90)Sr含量进行测定时,既不需要进行化学分离,也不需要等待^(90)Sr/^(90)Y放射性衰变平衡。 展开更多
关键词 液闪 淬灭指数 改进双窗法 线性拟合 ^(90)Sr ^(90)Y
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结构拓扑优化ICM方法的B映射求解途径
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作者 彭细荣 隋允康 +1 位作者 叶红玲 铁军 《固体力学学报》 北大核心 2025年第2期162-176,共15页
本文基于结构拓扑优化的ICM(独立、连续和映射的简称)方法,发展出了双映射接力运作的求解途径,因“双”的英文简称为B,故称之为B-ICM求解途径.该途径由两步组成:第一步是L(线性)映射作用于结构拓扑优化问题,使之成为离散模型,然后构造... 本文基于结构拓扑优化的ICM(独立、连续和映射的简称)方法,发展出了双映射接力运作的求解途径,因“双”的英文简称为B,故称之为B-ICM求解途径.该途径由两步组成:第一步是L(线性)映射作用于结构拓扑优化问题,使之成为离散模型,然后构造了约束函数;第二步是NL(非线性)映射作用于离散模型,使之成为连续模型,同时实现了单元拓扑变量由离散到连续的转换过程.以往ICM方法的求解途径中,上述第一步只是起到理论推导的作用,构造约束函数同其它建模与求解等算法均包含在第二步里,因此属于“一步求解”途径.B-ICM虽然属于“两步求解”途径,但是优化模型寻优仍然沿用ICM方法惯用的序列对偶二次规划算法.本文以位移约束的体积极小化结构拓扑优化问题为例,示例了上述建模及求解过程.单载荷工况和多载荷工况的算例,均印证了本文的研究实现了预期构想,与目前旨在得到清晰拓扑的3种方法(1、考虑Heaviside投影的SIMP方法;2、浮动投影拓扑优化<简称为FPTO>方法;3、非惩罚的光滑边界材料分布拓扑优化<简称为SEMDOT>方法),以及ICM方法以往的求解途径,进行了迭代次数、清晰程度、寻优能力等方面的对比,结果表明B-ICM求解途径表现最好.本文研究不仅丰富了ICM方法建模策略,推动了ICM方法求解途径的完善,也为解决模糊边界问题提供了一种优越的做法.过往的连续体结构拓扑优化求解,因消除棋盘格和网格依赖性问题而采取的过滤操作导致最优拓扑构型产生模糊边界,而且过滤半径越大,则边界越模糊.本文克服了这些令人堪忧的问题,可以成功地得到最优拓扑构型的清晰边界.值得提及的是,本文研究的关键技术,可以移植到包括变密度方法等所有连续变量优化的方法中. 展开更多
关键词 结构拓扑优化 ICM方法 两步求解途径 线性映射 非线性映射 位移约束的体积极小化问题
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用微元思想讨论热力学过程中的纯吸热和纯放热
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作者 郑小娟 潘江陵 +1 位作者 邹慧 李新梅 《物理通报》 2025年第9期31-34,共4页
以一道求循环效率的奥赛题为例,用微元思想讨论了求循环效率时涉及的热力学过程中系统纯吸热和纯放热的问题.给出了判断p-V图中负斜率的直线过程中,吸热和放热转折点以及纯吸热和纯放热区域的3种方法:1)把元过程中吸收或放出的热量dQ写... 以一道求循环效率的奥赛题为例,用微元思想讨论了求循环效率时涉及的热力学过程中系统纯吸热和纯放热的问题.给出了判断p-V图中负斜率的直线过程中,吸热和放热转折点以及纯吸热和纯放热区域的3种方法:1)把元过程中吸收或放出的热量dQ写成体积V和体积元增量dV的函数dQ(V,dV),根据体积变化来进行判断;2)把dQ写成V和dV以及压强p和其元增量dp的函数,利用绝热线作为参考线来进行判断;3)根据元过程熵变dS和dQ的关系,利用dS(V,dV)来进行判断.这些方法的运用能帮助学生更好地理解物理现象的本质. 展开更多
关键词 微元思想 循环效率 纯吸热和纯放热 p-V图中负斜率的直线过程 吸热和放热转折点
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REFINED HYBRID MINDLIN PLATE ELEMENT FOR GEOMETRICALLY NON LINEAR ANALYSIS
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作者 郑世杰 陶宝祺 陈万吉 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2000年第1期90-94,共5页
Based upon a generalized variational principle, which relaxed the inter element continuity requirements, a novel refined hybrid Mindlin plate element is developed, its non linear element stiffness matrices are decom... Based upon a generalized variational principle, which relaxed the inter element continuity requirements, a novel refined hybrid Mindlin plate element is developed, its non linear element stiffness matrices are decomposed into a series of matrices with respect to the assumed strain modes. The formulation presented in this paper is different from any other non linear mixed/hybrid element formulation all successful experience of linear hybrid formulation is absorbed into the formulation(adding non conforming modes and realizing orthogonalization) Numerical results show that the present approach is more effective than any other non linear hybrid element formulation over the accuracy and computational efficiency. In addition, non conforming modes can also overcome the shear locking effect. 展开更多
关键词 non linear mechanics non conforming mode orthogonal approach geometrically non linear refined element
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海上锤击沉桩过程对既有引桥影响研究 被引量:1
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作者 薄其睿 李成川 +2 位作者 尚文昌 高昌 刘俊伟 《交通科学与工程》 2025年第2期86-96,共11页
【目的】探讨海上大直径开口钢管桩锤击沉桩对邻近既有引桥的影响,确保施工安全与质量,维护引桥稳定。【方法】采用高精度现场监测技术,对沉桩过程中引桥的振动、水平位移进行实时监测。【结果】既有引桥主要受竖直方向的振动和顺桥方... 【目的】探讨海上大直径开口钢管桩锤击沉桩对邻近既有引桥的影响,确保施工安全与质量,维护引桥稳定。【方法】采用高精度现场监测技术,对沉桩过程中引桥的振动、水平位移进行实时监测。【结果】既有引桥主要受竖直方向的振动和顺桥方向水平位移的影响,尤其是振源附近的桥墩,其响应更为显著。通过多元线性回归分析,揭示了振动速度峰值与打桩距离、贯入深度之间的关系。具体来说,在振源附近,打桩距离和贯入深度的回归系数分别为-0.635和0.568,表明振动速度随着打桩距离的增大而减小,随着贯入深度的增大而增大。相反,在远离振源的区域,打桩距离和贯入深度的回归系数分别为0.678和-0.422,表明振动速度随着打桩距离的增大而增大,随着贯入深度的增加而减小。此外,引桥的水平位移也随着打桩距离的增大而减小,尤其是在振源附近的桥墩,其水平位移更为显著。水平位移随贯入深度的增加呈先增大后减少的变化趋势,特别是在桩基入岩时,水平位移达到了峰值。【结论】揭示了土层-结构相互作用下位移与振动的复杂性,可为海上沉桩施工提供实时数据支持,也可为类似工程的安全控制与质量保障提供科学依据。 展开更多
关键词 锤击沉桩 大直径开口管桩 现场监测 既有引桥影响 多元线性回归
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基于新型健康特征的锂电池健康状态快速估计方法 被引量:3
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作者 董晓红 董进波 +2 位作者 王明深 曾飞 潘益 《电力工程技术》 北大核心 2025年第1期136-142,206,共8页
锂电池健康状态(state of health,SOH)的在线估计是锂电池管理系统中必不可少的一部分。大部分基于数据驱动的锂电池SOH估计方法由于计算量较大,难以在锂电池管理系统微控制器中在线使用。因此,文中提出基于新型健康特征的锂电池SOH快... 锂电池健康状态(state of health,SOH)的在线估计是锂电池管理系统中必不可少的一部分。大部分基于数据驱动的锂电池SOH估计方法由于计算量较大,难以在锂电池管理系统微控制器中在线使用。因此,文中提出基于新型健康特征的锂电池SOH快速估计方法。首先,分析锂电池的充电数据,基于已有的锂电池恒流充电过程的等压升时间(time interval of an equal charging voltage difference,TIECVD)健康特征,构建一个同充电电压起点、同充电时间间隔的健康特征。其次,文中提出基于新型健康特征和多元线性回归(multiple linear regression,MLR)的锂电池SOH快速估计方法。然后,通过对牛津锂电池老化数据集和美国国家航空航天局锂电池随机使用数据集进行分析,以0.01 V步长遍历恒流充电电压区间,以皮尔逊相关系数最大为目标,确定锂电池最优的起始电压。最后,考虑不同充电时间间隔,利用最小二乘(ordinary least squares,OLS)回归分析方法,确定锂电池最优充电时间间隔参数。使用2个数据集划分的训练集建立MLR模型,使用2个数据集划分的验证集对文中方法进行验证。实验结果表明,文中基于新型健康特征方法可极大缩减计算量,并且可以在保障预测精度的前提下实现锂电池SOH的快速估计。 展开更多
关键词 锂电池 健康状态(SOH)估计 新型健康特征 数据驱动方法 多元线性回归(MLR) 充电电压数据片段
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新型滑模协同推力脉动抑制的LPMM速度控制
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作者 白聪 尹忠刚 高翌轩 《电力电子技术》 2025年第5期11-15,共5页
速度控制性能直接决定了线性永磁电机(LPMM)控制系统的关键技术指标。为实现LPMM的高性能速度控制,本文提出一种结合推力脉动抑制的新型指数趋近律滑模速度控制方法。首先,针对常规指数趋近律抖振明显、响应速度较慢等问题,提出一种基... 速度控制性能直接决定了线性永磁电机(LPMM)控制系统的关键技术指标。为实现LPMM的高性能速度控制,本文提出一种结合推力脉动抑制的新型指数趋近律滑模速度控制方法。首先,针对常规指数趋近律抖振明显、响应速度较慢等问题,提出一种基于新型指数趋近律的滑模控制(SMC)方法。其次,由齿槽效应、电流偏置和磁通谐波引起的推力脉动,会导致速度脉动进而降低LPMM控制性能。针对该问题,设计一种雅可比线性观测器实时估计推力脉动并进行前馈补偿,从而减小推力脉动对系统性能的影响。实验结果表明,与常规指数趋近律滑模控制方法相比,本文提出的新型指数趋近律滑模控制协同雅可比线性观测器显著提高了系统的动态性能和稳态性能,有效抑制了推力脉动并提高了控制精度。 展开更多
关键词 线性永磁电机 滑模控制 指数趋近律 推力脉动
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Re-evaluation of an operating hazardous landfill site considering the conflict with neighboring inhabitants by multi-criteria decision
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作者 AYDI Abdelwaheb AQIL Tariq +1 位作者 SIFI Sinda ALZAHRANI Hassan 《Journal of Mountain Science》 2025年第3期1001-1014,共14页
Judicious selection of landfill allocation is crucial since inappropriate dumping of wastes can negatively impact human health and degrade the ecosystem.Therefore,this survey presents an integration multi-criteria dec... Judicious selection of landfill allocation is crucial since inappropriate dumping of wastes can negatively impact human health and degrade the ecosystem.Therefore,this survey presents an integration multi-criteria decision approach with the geographic information system for re-evaluating the pending hazardous landfill in Jradou,Tunisia,considering the conflict with neighboring inhabitants.The study involved twelve constraints and eight factors relevant to environmental and socio-economic challenges based on international works,guidelines of the country’s legislation,and an assessment questionnaire on the landfill suitability map.The Analytic Hierarchy Process(AHP)apportioned weights to criteria,and a Weighted Linear Combination(WLC)approach generated landfill suitability maps(LSM).Afterward,the produced LSM revealed that 2%(8.46km²)of the land was classified as very high,followed by 48%(203.04km²)as high,25%(105.75km²)as moderate,10%(42.3km²)as low,and the remaining 15%(63.45km²)as very low suitable.Furthermore,the operating hazardous waste landfill of Jradou falls within unsuitable areas,inflicting severe harm on the neighboring.The pending hazardous landfill of Jradou should be closed,and a new site must be identified.Conversely,the highly suitable classes are further identified in(1)the Eastern part of the study area,near Ouled ben Amara,and(2)the Northern part of Zaghouan,at 2 km north of Smenja,for potential future hazardous waste landfills.Consequently,governments and relevant stakeholders should investigate these zones to locate new landfills. 展开更多
关键词 Hazardous waste LANDFILLING Multi-criteria decision approach Weighted linear Combination
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New strategy for fault detection and classification in wind turbines based on doubly-fed induction generators
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作者 Boaz Wadawa Joseph Yves Effa 《Global Energy Interconnection》 2025年第4期668-684,共17页
A novel robust diagnostic system based on a linear fractional transform(LFT)representation combined with a static redundancy approach is proposed to design a residual generator for fault detection and localization in ... A novel robust diagnostic system based on a linear fractional transform(LFT)representation combined with a static redundancy approach is proposed to design a residual generator for fault detection and localization in a wind system using the doubly fed induction generator(DFIG).As a result,faults in DFIG-based grid-connected wind systems can be grouped into three classes of faults,namely,model uncertainty-related faults(FLMU),set point disturbance-related faults(FLDS)and parameter uncertainty-related faults(FLPU).Based on the parity-space residual generations,an artificial neural network(ANN)structure has been combined with the classification to enable the assessment of hidden,indistinguishable or small amplitude faults.The training validation with two data sizes of 1278*4 and 1278*1 respectively at the inputs and outputs of the proposed ANN,presents better performance for a mean squared error value(MSE=3.0532e 9),and a good correlation between outputs and targets for a regression value(R=1).It emerges that the proposed robust and complete diagnostic system for the optimal and sustainable integration of wind turbines into the grid,offers very great advan-tages,particularly with regard to the precise and rapid detection of faults,and the assessment of hidden faults and/or ambiguous fault states in the wind system based on DFIG.In addition,the proposed approach allows the use of a reduced number of data,sensors and actuators required.Consequently,the system maintenance difficulties,complexity and cost of the diagnostic system are reduced. 展开更多
关键词 Classification Diagnostic system Static redundancy approach linear Fractional Transformation(LFT) Artificial Neural Network(ANN)
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基于时段分组的高寒草原牧草产量气象驱动机制与预测模型研究
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作者 杨斐 刘文兵 +1 位作者 张海春 马文元 《中国农学通报》 2025年第30期131-136,共6页
本研究旨在探讨气象因子对高寒草原牧草产量的分时段调控机制,为草地资源管理及产量预测提供科学依据。基于青海省同德县巴滩高寒草原2005—2023年的牧草鲜草产量及气象数据,采用时段分组法划分13个气象时段,并运用相关性分析和多元线... 本研究旨在探讨气象因子对高寒草原牧草产量的分时段调控机制,为草地资源管理及产量预测提供科学依据。基于青海省同德县巴滩高寒草原2005—2023年的牧草鲜草产量及气象数据,采用时段分组法划分13个气象时段,并运用相关性分析和多元线性回归模型,解析降水、温度、湿度、日照和风速等因子对牧草产量的影响及其时段特异性。结果显示:牧草产量呈弱增长趋势(气候倾向率1801.4 kg/(hm^(2)·10a)),变异系数达59.3%,表明其对气候波动响应敏感。降水是主要的促进因子,在生长盛期(5—8月)的效应最显著(r=0.294);相对湿度在生长后期通过调节蒸汽压亏缺发挥补偿作用(5—8月r=0.462);日照与风速呈持续抑制效应;温度作用具时段性,春季促进生长,而夏季影响不显著。构建的产量预测模型(R^(2)=0.934)识别出3个关键因子:上年12月至当年8月的累积降水、5—8月均温和上年11月至当年8月的平均相对湿度。研究表明,高寒草原牧草产量主要受水分调控,且多因子间存在显著的时序互作效应,体现出“水热耦合、阶段互补”的生态适应策略。建议依据物候阶段制定针对性管理措施,并聚焦关键时段的气象变量,以提升产量预测的精度。 展开更多
关键词 高寒草原 牧草产量 气象因子 相对湿度 时段分组法 产量预测 多元线性回归 温湿协同
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温度预报对呼吸系统疾病的潜在健康效应和经济效益评估
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作者 张兴山 付桂琴 +3 位作者 刘华悦 李猛 王浩宇 赵越 《环境与健康杂志》 2025年第7期565-574,共10页
目的探讨温度预报在呼吸系统疾病发病风险中的调节作用,评估温度预报准确率提升在减少呼吸系统疾病健康风险方面的潜在经济价值。方法利用邯郸市2016—2019年逐日呼吸系统疾病数据、气象监测、天气预报数据及空气污染数据,运用广义相加... 目的探讨温度预报在呼吸系统疾病发病风险中的调节作用,评估温度预报准确率提升在减少呼吸系统疾病健康风险方面的潜在经济价值。方法利用邯郸市2016—2019年逐日呼吸系统疾病数据、气象监测、天气预报数据及空气污染数据,运用广义相加模型,构建气温预报准确、高估、低估情景下气温与疾病的暴露反应关系,以预报完全准确为基准评估温度预报的健康效应,采用疾病成本法计算潜在经济价值。结果气温预报准确性随预报时间的临近而提高,由前3 d的67.2%提升至当日的81.5%,相对更易出现低估。总体相对风险在低于最适气温时的高估和高于最适气温时的低估均增加,反之降低;最大单日相对风险在低温阶段高估和高温阶段低估时增加,低温阶段低估降低,过渡阶段随气温降低呈交叉增加特征。逐年气温对疾病的影响在预报准确时最低且稳定,高估和低估分别呈增加和减少趋势。不同季节中,春、夏、秋季低估增加发病影响,夏季最明显;秋、冬季高估增加发病影响,影响程度相当,但冬季发病基数大。假设预报完全准确,每年可减少4万就诊人数,冬季最多,秋季次之,春季最少。减少低估时四季均带来健康效益,减少高估时在秋、冬季有益,且冬季更优。每年潜在减少经济价值在1222.2~1610.8万元之间,低估情况下潜在减少的经济价值比高估多近3倍,冬季减少最多;减少低估时四季均减少经济损失,冬季最优,减少高估时在春、夏季增加经济损失,秋、冬季减少经济损失。结论温度预报准确性可明显影响呼吸系统疾病发病风险及相关经济价值,减少预报低估和合理应对高估对降低疾病风险、减少经济损失具有重要意义,尤其在冬季时作用更为突出。 展开更多
关键词 暴露反应关系 广义相加模型 分布滞后模型 归因分析 疾病成本法
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Non-fragile Observer Design for Fractional-order One-sided Lipschitz Nonlinear Systems 被引量:3
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作者 Yong-Hong Lan Wen-Jie Li +1 位作者 Yan Zhou Yi-Ping Luo 《International Journal of Automation and computing》 EI CSCD 2013年第4期296-302,共7页
This paper is concerned with the problem of the full-order observer design for a class of fractional-order Lipschitz nonlinear systems. By introducing a continuous frequency distributed equivalent model and using an i... This paper is concerned with the problem of the full-order observer design for a class of fractional-order Lipschitz nonlinear systems. By introducing a continuous frequency distributed equivalent model and using an indirect Lyapunov approach, the sufficient condition for asymptotic stability of the full-order observer error dynamic system is presented. The stability condition is obtained in terms of LMI, which is less conservative than the existing one. A numerical example demonstrates the validity of this approach. 展开更多
关键词 FRACTIONAL-ORDER nonlinear system observer design indirect Lyapunov approach linear matrix inequality (LMI).
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