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曲线坐标下平面二维污染物扩散输移的代数应力湍流模型

吴修广,沈永明,王敏,杨志峰

《中国工程科学》 2005年第7卷第7期页码 60-64

摘要：采用具有浓度实测值的实验室连续弯道进行模型验证，对本模型计算的浓度分布与k-ε模型进行比较，结果显示了本模型在处理各向异性明显优于k-ε模型。

关键词：污染物扩散输移各向异性代数应力湍流模型 k-ε模型

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有限资源下最大可靠性网络流中断模型

赵佳,于华

《中国工程科学》 2015年第17卷第1期页码 137-142

摘要：

提出了最大可靠性网络流中断模型。此模型是在给定的网络图中，通过在边上设置监测点来阻止给定两个顶点之间的网络流量，同时考虑所设置监测点失效的可能，在给定的资源限制下，最大化中断网络流的可能性，即给定起点和终点的网络图，在资源有限的情况下，选择一些边设置监测点使得从起点到终点的所有路都包含尽可能多的已被设置中断点的边。在给定图中，两点之间的路的条数是图的规模的指数次幂，为此将此模型转化为双层整数规划模型，鉴于双层整数规划模型在一般情况下是不可解的，通过探讨下层整数规划问题与其线性规划松弛之间的关系以及线性规划对偶理论来解此双层整数规划模型。本文不仅将该模型约束的个数从图的规模的指数次幂降到一次幂，同时也提供了一种解双层整数规划问题的方法。

关键词：中断模型；k-可靠性；对偶；线性规划松弛；互补松弛型

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基于VOF法的风暴潮洪水演进三维数值模拟

王晓玲,孙宜超,陈华鸿,杨丽美,孙蕊蕊

《中国工程科学》 2011年第13卷第12期页码 56-62

摘要：

为了提高风暴潮灾害应急处置能力，确保防潮安全，文章建立了耦合流体体积函数（VOF）法的三维非稳态水气两相流k－ε模型，采用等效糙率的方法处理城市密集建筑群

关键词：风暴潮洪水演进流体体积函数（VOF）法三维k－ε紊流数学模型水深分布

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独头巷道受限贴附射流流场特征模拟实验研究

王海桥,刘荣华,陈世强

《中国工程科学》 2004年第6卷第8期页码 45-49

摘要：基于流体动力学和射流理论，建立了独头巷道压入式受限贴附射流通风的紊流k-ε数学模型，分析了计算边界条件，并应用PHOENICS3.4计算流体动力学(CFD)软件模拟了独头巷道射流通风三维流场

关键词：独头巷道受限贴附射流 k-ε模型数值计算

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利用机器视觉技术对化工厂管道进行自动视觉泄漏检测与定位 Reiew

Mina Fahimipirehgalin, Emanuel Trunzer, Matthias Odenweller, Birgit Vogel-Heuser

《工程（英文）》 2021年第7卷第6期页码 758-776 doi: 10.1016/j.eng.2020.08.026

摘要：在本方法中，首先对后续帧进行减影和分块处理，然后对每一分块进行主成分分析，提取特征；接着将分块内所有减影帧都转换为特征向量（作为块分类的依据），根据特征向量，采用k-最近邻算法将块分为正常（无泄漏）和异常

关键词：泄漏检测与定位图像分析图像预处理主成分分析 k-最近邻分类

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Evaluation of the k-nearest neighbor method for forecasting the influent characteristics of wastewater

Minsoo KIM,Yejin KIM,Hyosoo KIM,Wenhua PIAO,Changwon KIM

《环境科学与工程前沿（英文）》 2016年第10卷第2期页码 299-310 doi: 10.1007/s11783-015-0825-7

摘要： The k-nearest neighbor (k-NN) method was evaluated to predict the influent flow rate and four water qualities, namely chemical oxygen demand (COD), suspended solid (SS), total nitrogen (T-N) and total phosphorus (T-P) at a wastewater treatment plant (WWTP). The search range and approach for determining the number of nearest neighbors (NNs) under dry and wet weather conditions were initially optimized based on the root mean square error (RMSE). The optimum search range for considering data size was one year. The square root-based (SR) approach was superior to the distance factor-based (DF) approach in determining the appropriate number of NNs. However, the results for both approaches varied slightly depending on the water quality and the weather conditions. The influent flow rate was accurately predicted within one standard deviation of measured values. Influent water qualities were well predicted with the mean absolute percentage error (MAPE) under both wet and dry weather conditions. For the seven-day prediction, the difference in predictive accuracy was less than 5% in dry weather conditions and slightly worse in wet weather conditions. Overall, the k-NN method was verified to be useful for predicting WWTP influent characteristics.

关键词： influent wastewater prediction data-driven model k-nearest neighbor method (k-NN)

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load carrying capacity of batter pile groups using neural network, random forest regression and M5 model

K. ARORA

《结构与土木工程前沿（英文）》 2019年第13卷第3期页码 674-685 doi: 10.1007/s11709-018-0505-3

摘要： M5 model tree, random forest regression (RF) and neural network (NN) based modelling approaches were used to predict oblique load carrying capacity of batter pile groups using 247 laboratory experiments with smooth and rough pile groups. Pile length ( ), angle of oblique load ( ), sand density ( ), number of batter piles ( ), and number of vertical piles ( ) as input and oblique load ( ) as output was used. Results suggest improved performance by RF regression for both pile groups. M5 model tree provides simple linear relation which can be used for the prediction of oblique load for field data also. Model developed using RF regression approach with smooth pile group data was found to be in good agreement for rough piles data. NN based approach was found performing equally well with both smooth and rough piles. Sensitivity analysis using all three modelling approaches suggest angle of oblique load ( ) and number of batter pile ( ) affect the oblique load capacity for both smooth and rough pile groups.

关键词： batter piles oblique load test neural network M5 model tree random forest regression ANOVA

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Optimal design and development of PV-wind-battery based nano-grid system: A field-on-laboratory demonstration

TUDU, K. K. MANDAL, N. CHAKRABORTY

《能源前沿（英文）》 2019年第13卷第2期页码 269-283 doi: 10.1007/s11708-018-0573-z

摘要： The present paper has disseminated the design approach, project implementation, and economics of a nano-grid system. The deployment of the system is envisioned to acculturate the renewable technology into Indian society by field-on-laboratory demonstration (FOLD) and “bridge the gaps between research, development, and implementation.” The system consists of a solar photovoltaic (PV) (2.4 kWp), a wind turbine (3.2 kWp), and a battery bank (400 Ah). Initially, a prefeasibility study is conducted using the well-established HOMER (hybrid optimization model for electric renewable) software developed by the National Renewable Energy Laboratory (NREL), USA. The feasibility study indicates that the optimal capacity for the nano-grid system consists of a 2.16 kWp solar PV, a 3 kWp wind turbine, a 1.44 kW inverter, and a 24 kWh battery bank. The total net present cost (TNPC) and cost of energy (COE) of the system are US$20789.85 and US$0.673/kWh, respectively. However, the hybrid system consisting of a 2.4 kWp of solar PV, a 3.2 kWp of wind turbine, a 3 kVA of inverter, and a 400 Ah of battery bank has been installed due to unavailability of system components of desired values and to enhance the reliability of the system. The TNPC and COE of the system installed are found to be US$20073.63 and US$0.635/kWh, respectively and both costs are largely influenced by battery cost. Besides, this paper has illustrated the installation details of each component as well as of the system. Moreover, it has discussed the detailed cost breakup of the system. Furthermore, the performance of the system has been investigated and validated with the simulation results. It is observed that the power generated from the PV system is quite significant and is almost uniform over the year. Contrary to this, a trivial wind velocity prevails over the year apart from the month of April, May, and June, so does the power yield. This research demonstration provides a pathway for future planning of scaled-up hybrid energy systems or microgrid in this region of India or regions of similar topography.

关键词： photovoltaic (PV) wind battery nano-grid hybrid optimization model for electric renewable (HOMER) field-on-lab demonstration (FOLD)

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Assessment of a fuzzy logic based MRAS observer used in a photovoltaic array supplied AC drive

Bhavnesh KUMAR, Yogesh K CHAUHAN, Vivek SHRIVASTAVA

《能源前沿（英文）》 2014年第8卷第1期页码 81-89 doi: 10.1007/s11708-014-0295-9

摘要： In this paper a fuzzy logic (FL) based model reference adaptive system (MRAS) speed observer for high performance AC drives is proposed. The error vector computation is made based on the rotor-flux derived from the reference and the adaptive model of the induction motor. The error signal is processed in the proposed fuzzy logic controller (FLC) for speed adaptation. The drive employs an indirect vector control scheme for achieving a good closed loop speed control. For powering the drive system, a standalone photovoltaic (PV) energy source is used. To extract the maximum power from the PV source, a constant voltage controller (CVC) is also proposed. The complete drive system is modeled in MATLAB/Simulink and the performance is analyzed for different operating conditions.

关键词： induction motor drive fuzzy logic (FL) control model reference adaptive system (MRAS) photovoltaic (PV) array vector control

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Analysis of flow over backward facing step with transition

Dwarikanath RATHA,Arindam SARKAR

《结构与土木工程前沿（英文）》 2015年第9卷第1期页码 71-81 doi: 10.1007/s11709-014-0270-x

摘要： The present study deals with the study of the velocity distribution and the separation phenomenon of flow of air over a two dimensional backward facing step. The flow of air over a backward facing step has been investigated numerically using FLUENT. Flow simulation has been carried out in a backward facing step having an expansion ratio (ratio of the height before and after the step) of 1:1.94 and the results obtained are compared with the published experimental results. Comparison of flow characteristics between steps with three different transitions is made. The variation of reattachment length for all the three cases are analyzed for wide range of Reynolds number ranging from 100 to 7000 which covers the laminar, transition and turbulent flow of air. Simulation of the flow over steps with expansion ratios of 1:1.24, 1:1.38, 1:1.47, 1:1.53, 1:1.94, 1:2.20 are also carried out to examine the effect of different expansion ratios on the reattachment length. It is found that the primary reattachment length increases with increase in the expansion ratio. The primary reattachment length at the bottom wall downstream of the step is minimum for the step with round edged transition and maximum for the step with a vertical drop transition.

关键词： Reattachment length backward facing step transition flow separation k-? model

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A Bayesian modeling approach to bi-directional pedestrian flows in carnival events

K. LAM

《工程管理前沿（英文）》 2017年第4卷第4期页码 483-489 doi: 10.15302/J-FEM-2017023

摘要： Bi-directional pedestrian flows are common at crosswalks, footpaths, and shopping areas. However, the properties of pedestrian movement may vary in urban areas according to the type of walking facility. In recent years, crowd movements at carnival events have attracted the attention of researchers. In contrast to pedestrian behavior in other walking facilities, pedestrians whose attention is attracted by carnival displays or activities may slow down and even stop walking. The Lunar New Year Market is a traditional carnival event in Hong Kong held annually one week before the Lunar New Year. During the said event, crowd movements can be easily identified, particularly in Victoria Park, where the largest Lunar New Year Market in Hong Kong is hosted. In this study, we conducted a video-based observational survey to collect pedestrian flow and speed data at the Victoria Park Lunar New Year Market on the eve of the Lunar New Year. Using the collected data, an extant mathematical model was calibrated to capture the relationships between the relevant macroscopic quantities, thereby providing insight into pedestrian behavior at the carnival event. Bayesian inference was employed to calibrate the model by using prior data obtained from a previous controlled experiment. Results obtained enhance our understanding of crowd behavior under different conditions at carnival events, thus facilitating the improvement of the safety and efficiency of similar events in the future.

关键词： pedestrian flow model bi-directional interactions empirical studies Bayesian inference

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Update on Mayer–Rokitansky–Küster–Hauser syndrome

《医学前沿（英文）》 2022年第16卷第6期页码 859-872 doi: 10.1007/s11684-022-0969-3

摘要： This review presents an update of Mayer–Rokitansky–Küster–Hauser (MRKH) syndrome on its etiologic, clinical, diagnostic, psychological, therapeutic, and reproductive aspects. The etiology of MRKH syndrome remains unclear due to its intrinsic heterogeneity. Nongenetic and genetic causes that may interact during the embryonic development have been proposed with no definitive etiopathogenesis identified. The proportion of concomitant extragenital malformations varies in different studies, and the discrepancies may be explained by ethnic differences. In addition to physical examination and pelvic ultrasound, the performance of pelvic magnetic resonance imaging is crucial in detecting the presence of rudimentary uterine endometrium. MRKH syndrome has long-lasting psychological effects on patients, resulting in low esteem, poor coping strategies, depression, and anxiety symptoms. Providing psychological counseling and peer support to diagnosed patients is recommended. Proper and timely psychological intervention could significantly improve a patient’s outcome. Various nonsurgical and surgical methods have been suggested for treatment of MRKH syndrome. Due to the high success rate and minimal risk of complications, vaginal dilation has been proven to be the first-line therapy. Vaginoplasty is the second-line option for patients experiencing dilation failure. Uterine transplantation and gestational surrogacy are options for women with MRKH syndrome to achieve biological motherhood.

关键词： MRKH (Mayer–Rokitansky–Küster–Hauser) syndrome etiology clinical characteristic diagnosis treatment psychological effect

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Developing the QSPR model for predicting the storage lipid/water distribution coefficient of organic

Miao Li, Jian Li, Yuchen Lu, Cenyang Han, Xiaoxuan Wei, Guangcai Ma, Haiying Yu

《环境科学与工程前沿（英文）》 2021年第15卷第2期 doi: 10.1007/s11783-020-1316-z

摘要： Abstract • A predictive model for storage lipid/water distribution coefficient was developed. • The model yields outstanding fitting performance, robustness, and predictive ability. • Hydrophobic and electrostatic interactions and molecular size dominate log Klip/w. • The model can be used in a wide application domain to predict log Klip/w values. The distribution of organic compounds in stored lipids affects their migration, transformation, bioaccumulation, and toxicity in organisms. The storage lipid/water distribution coefficient (log Klip/w) of organic chemicals, which quantitatively determines such distribution, has become a key parameter to assist their ecological security and health risk. Due to the impossibility to measure Klip/w values for a huge amount of chemicals, it is necessary to develop predictive approaches. In this work, a quantitative structure-property relationship (QSPR) model for estimating log Klip/w values of small organic compounds was constructed based on 305 experimental log Klip/w values. Quantum chemical descriptors and n-octanol/water partitioning coefficient were employed to characterize the intermolecular interactions that dominate log Klip/w values. The hydrophobic and electrostatic interactions and molecular size have been found to play important roles in governing the distribution of chemicals between lipids and aqueous phases. The regression (R2 = 0.959) and validation (Q2 = 0.960) results indicate good fitting performance and robustness of the developed model. A comparison with the predictive performance of other commercial software further proves the higher accuracy and stronger predictive ability of the developed Klip/w predictive model. Thus, it can be used to predict the Klip/w values of cycloalkanes, long-chain alkanes, halides (with fluorine, chlorine, and bromine as substituents), esters (without phosphate groups), alcohols (without methoxy groups), and aromatic compounds.

关键词： Storage lipid/water distribution coefficient log K_lip/w Organic compounds QSPR Quantum chemical descriptors

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用智能药丸提供胰岛素？

Elizabeth K. Wilson

《工程（英文）》 2019年第5卷第4期页码 603-604 doi: 10.1016/j.eng.2019.07.008

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Stochastic analysis of laminated composite plate considering stochastic homogenization problem

SAKATA,K. OKUDA,K. IKEDA

《结构与土木工程前沿（英文）》 2015年第9卷第2期页码 141-153 doi: 10.1007/s11709-014-0286-2

摘要： This paper discusses a multiscale stochastic analysis of a laminated composite plate consisting of unidirectional fiber reinforced composite laminae. In particular, influence of a microscopic random variation of the elastic properties of component materials on mechanical properties of the laminated plate is investigated. Laminated composites are widely used in civil engineering, and therefore multiscale stochastic analysis of laminated composites should be performed for reliability evaluation of a composite civil structure. This study deals with the stochastic response of a laminated composite plate against the microscopic random variation in addition to a random variation of fiber orientation in each lamina, and stochastic properties of the mechanical responses of the laminated plate is investigated. Halpin-Tsai formula and the homogenization theory-based finite element analysis are employed for estimation of effective elastic properties of lamina, and the classical laminate theory is employed for analysis of a laminated plate. The Monte-Carlo simulation and the first-order second moment method with sensitivity analysis are employed for the stochastic analysis. From the numerical results, importance of the multiscale stochastic analysis for reliability evaluation of a laminated composite structure and applicability of the sensitivity-based approach are discussed.

关键词： stochastic homogenization multiscale stochastic analysis microscopic random variation laminated composite plate