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An approach to calculating allowable watershed pollutant loads

Yu GUO, Haifeng JIA

《环境科学与工程前沿（英文）》 2012年 第6卷 第5期   页码 658-671 doi: 10.1007/s11783-012-0446-3

摘要： To improve the management of discharge pollutants loads in the reservoirs’ watershed, an approach of the allowable pollutants loads calculation and its allocation, based on the water environment model, was proposed. Establishment of the approach framework was described at first. Under the guidance of this framework, two major steps were as follows: modeling and scenario analysis were involved and should be applied to support the decision of discharge loads management; Environmental Fluid Dynamic Code (EFDC) model was selected as the kernel model in this framework. In modeling step, spatial discretization for establishing cell map in model, data preprocessing, parameter calibration and uncertainty analysis (which is considered as the significantly relevant factor of the margin of safety (MOS)), were conducted. As a result of the research, the model-based approach presented as a combination of estimation and precise calculation, which contributed to scenario analysis step. Some integrated modules, such as scenario simulation, result analysis and plan optimization were implemented as cycles in the scenario analysis. Finally, allowable pollutant loads under various conditions were calculated. The Chaihe Reservoir in Liaoning Province, China was used as a case study for an application of the approach described above. Results of the Chaihe reservoir water quality simulation, show good agreement with field data and demonstrated that the approach used in the present study provide an efficient and appropriate methodology for pollutant load allocation.

关键词： Source water protection     watershed management     pollutants load allocation     Environmental Fluid Dynamic Code (EFDC) modeling     margin of safety     statistical analysis    

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Experimental study of wind loads on gable roofs of low-rise buildings with overhangs

Peng HUANG, Ling TAO, Ming GU, Yong QUAN

《结构与土木工程前沿（英文）》 2018年 第12卷 第3期   页码 300-317 doi: 10.1007/s11709-018-0449-7

摘要：

Gable roofs with overhangs (eaves) are the common constructions of low-rise buildings on the southeastern coast of China, and they were vulnerable to typhoons from experience. The wind pressure distributions on gable roofs of low-rise buildings are investigated by a series of wind tunnel tests which consist of 99 test cases with various roof pitches, height-depth ratios and width-depth ratios. The block pressure coefficients and worst negative (block) pressure coefficients on different roof regions of low-rise buildings are proposed for the main structure and building envelope, respectively. The effects of roof pitch, height-depth ratio, and width-depth ratio on the pressure coefficients of each region are analyzed in detail. In addition, the pressure coefficients on the roofs for the main structure and building envelope are fitted according to roof pitch, height-depth ratio and width-depth ratio of the low-rise building. Meanwhile, the rationality of the fitting formulas is verified by comparing the fitting results with the codes of different countries. Lastly, the block pressure coefficients and worst negative pressure coefficients are recommended to guide the design of low-rise buildings in typhoon area and act as references for the future’s modification of wind load codes.

关键词： low-rise building     gable roof     wind loads     wind tunnel test     block pressure coefficient     load code    

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Optimization of spatial structure designs of control rod using Monte Carlo code RMC

《能源前沿（英文）》 2021年 第15卷 第4期   页码 974-983 doi: 10.1007/s11708-021-0769-5

摘要： Control rod is the most important approach to control reactivity in reactors, which is currently a cluster of pins filled with boron carbide (B4C). In this case, neutrons are captured in the outer region, and thus the inner absorber is inefficient. Moreover, the lifetime of the control rod is challenged due to the high reactivity worth loss resulted from the excessive degradation of B4C in the high flux area. In this work, some control rod designs are proposed with optimized spatial structures including the spatially mixed rod, radially moderated rod, and composite control rod with small-sized pins. The control rod worth and effective absorption cross section of these designs are computed using the Monte Carlo code RMC. A long-time depletion calculation is conducted to evaluate their burnup stability. For the spatially mixed rod, rare-earth absorbers are combined with B4C in spatial structure. Compared with the homogenous B4C rod, mixed designs ensure more sufficient reactivity worth in the lifetime of the reactor. The minimum reactivity loss at the end of the cycle is only 1.8% from the dysprosium titanate rod, while the loss for pure B4C rod is nearly 12%. For the radially moderated design, a doubled neutronic efficiency is achieved when the volume ratio of moderator equals approximately 0.3, while excessive moderating may lead to the failure of control rods. The control rod with small-sized pins processes an enhanced safety performance and saves the investment in absorbers. The rod worth can be further enhanced by introducing small moderator pins, and the reactivity loss caused by the reduction of absorbers is sustainable.

关键词： control rod     optimized spatial structure     neutronic performance     burnup stability    

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Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

《能源前沿（英文）》 2015年 第9卷 第4期   页码 472-485 doi: 10.1007/s11708-015-0373-7

摘要： It is well recognized that the voltage stability of a power system is affected by the load model and hence, to effectively analyze the reactive power compensation of an isolated hybrid wind-diesel based power system, the loads need to be considered along with the generators in a transient analysis. This paper gives a detailed mathematical modeling to compute the reactive power response with small voltage perturbation for composite load. The composite load is a combination of the static and dynamic load model. To develop this composite load model, the exponential load is used as a static load model and induction motors (IMs) are used as a dynamic load model. To analyze the dynamics of IM load, the fifth, third and first order model of IM are formulated and compared using differential equations solver in Matlab coding. Since the decentralized areas have many small consumers which may consist large numbers of IMs of small rating, it is not realistic to model either a single large rating unit or all small rating IMs together that are placed in the system. In place of using a single large rating IM, a group of motors are considered and then the aggregate model of IM is developed using the law of energy conservation. This aggregate model is used as a dynamic load model. For different simulation studies, especially in the area of voltage stability with reactive power compensation of an isolated hybrid power system, the transfer function of the composite load is required. The transfer function of the composite load is derived in this paper by successive derivation for the exponential model of static load and for the fifth and third order IM dynamic load model using state space model.

关键词： isolated hybrid power system (IHPS)     composite load model     static load     dynamic load     induction motor load model     aggregate load    

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EAI-oriented information classification code system in manufacturing enterprises

WANG Junbiao, DENG Hu, JIANG Jianjun, YANG Binghong, WANG Bailing

《机械工程前沿（英文）》 2008年 第3卷 第1期   页码 81-85 doi: 10.1007/s11465-008-0011-8

摘要： Although the traditional information classification coding system in manufacturing enterprises (MEs) emphasizes the construction of code standards, it lacks the management of the code creation, code data transmission and so on. According to the demands of enterprise application integration (EAI) in manufacturing enterprises, an enterprise application integration oriented information classification code system (EAIO-ICCS) is proposed. EAIO-ICCS expands the connotation of the information classification code system and assures the identity of the codes in manufacturing enterprises with unified management of codes at the view of its lifecycle.

关键词： EAI     EAIO-ICCS     management     classification     connotation    

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A MATLAB code for the material-field series-expansion topology optimization method

《机械工程前沿（英文）》 2021年 第16卷 第3期   页码 607-622 doi: 10.1007/s11465-021-0637-3

摘要： This paper presents a MATLAB implementation of the material-field series-expansion (MFSE) topo-logy optimization method. The MFSE method uses a bounded material field with specified spatial correlation to represent the structural topology. With the series-expansion method for bounded fields, this material field is described with the characteristic base functions and the corresponding coefficients. Compared with the conventional density-based method, the MFSE method decouples the topological description and the finite element discretization, and greatly reduces the number of design variables after dimensionality reduction. Other features of this method include inherent control on structural topological complexity, crisp structural boundary description, mesh independence, and being free from the checkerboard pattern. With the focus on the implementation of the MFSE method, the present MATLAB code uses the maximum stiffness optimization problems solved with a gradient-based optimizer as examples. The MATLAB code consists of three parts, namely, the main program and two subroutines (one for aggregating the optimization constraints and the other about the method of moving asymptotes optimizer). The implementation of the code and its extensions to topology optimization problems with multiple load cases and passive elements are discussed in detail. The code is intended for researchers who are interested in this method and want to get started with it quickly. It can also be used as a basis for handling complex engineering optimization problems by combining the MFSE topology optimization method with non-gradient optimization algorithms without sensitivity information because only a few design variables are required to describe relatively complex structural topology and smooth structural boundaries using the MFSE method.

关键词： MATLAB implementation     topology optimization     material-field series-expansion method     bounded material field     dimensionality reduction    

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基于近似子树匹配的快速代码推荐方法 Research Article

邵宜超1,2,3,黄志球1,2,3,李伟湋1,2,3,喻垚慎1,2,3

《信息与电子工程前沿（英文）》 2022年 第23卷 第8期   页码 1205-1216 doi: 10.1631/FITEE.2100379

摘要： 软件开发人员通常需编写与已有代码具有类似功能的代码，而帮助开发人员重用这些代码片段的代码推荐工具可显著提高软件开发效率。近年来许多研究者开始关注这一领域，并提出多种代码推荐方法。一些研究者使用序列匹配算法得到相关代码，这些方法往往效率较低，且只能利用代码中的文本信息。另一些研究者从代码中提取特征并形成特征向量，从而计算代码间相似性并得到推荐结果。然而特征向量相似往往不代表原始代码相似，在将抽象语法树转换为向量的过程中存在结构信息丢失问题。对此，我们提出一种基于近似子树匹配的代码推荐方法。与现有基于特征向量匹配的方法不同，该方法在匹配过程中保留了查询代码的树型结构，从而找到与当前查询在结构上最为相似的代码片段。此外，通过哈希思想将子树匹配问题转化为树与列表间的匹配，使得抽象语法树信息可以用于对时间要求较高的代码推荐任务。为评估方法的有效性，构建了多个涵盖不同语言和粒度的代码数据集。实验结果表明，该方法在所有数据集上的召回率均优于两种对比方法——SENSORY和Aroma，且可以应用于大型数据集。

关键词： 代码复用；代码推荐；树相似度；结构信息    

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代码变更驱动的增量式软件架构恢复技术 Research Article

王丽1,2,孔祥龙1,王家慧3,李必信1

《信息与电子工程前沿（英文）》 2022年 第23卷 第5期   页码 664-677 doi: 10.1631/FITEE.2100461

摘要： 在软件演化过程中，受开发能力和投入资源限制，软件架构通常难以与代码保持同步更新，导致架构设计与代码产生不一致，对软件维护等工作造成潜在影响。为解决此问题，本文提出一种增量式软件架构恢复技术，即ISAR。该技术首先从变更代码片段中提取依赖信息，然后根据依赖强度分析模块间关联关系，最后基于代码变更与架构更新间的关联关系设计两层分类器以恢复架构。本文基于10个开源项目构建验证实验，结果表明ISAR在架构恢复精度和效率方面优于传统技术。此外，本文发现架构设计文档质量对ISAR架构恢复精度有一定影响，但随着版本迭代逐渐趋于稳定。

关键词： 架构恢复；软件演化；代码变更    

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ShortTail：降低纠删码内存存储系统的尾部延迟 Research Article

滕云1,3,李之悦2,4,黄晶1,3,张广艳2,4

《信息与电子工程前沿（英文）》 2022年 第23卷 第11期   页码 1646-1657 doi: 10.1631/FITEE.2100566

摘要：

为获得高性能和高数据可用性，基于纠删码的内存存储系统得到广泛应用。然而，随着集群规模不断增长，服务器级别的性能降级问题出现得越来越频繁，进而导致长尾延迟。在基于纠删码的系统中，由于一个纠删码操作可能依赖于多个子操作的同步完成，长尾延迟的影响被进一步放大。本文提出一种称为ShortTail的基于纠删码的内存存储系统，该系统可实现稳定的性能和较低的读写延迟。首先，ShortTail使用轻量请求监视器监测每个内存节点性能，以便及时发现性能降级节点。其次，ShortTail选择性执行降级读操作和重定向写操作，以避免访问性能降级节点。最后，ShortTail采用一种自适应写策略降低小写请求的写放大程度。本文在Memcached上实现了ShortTail，并将其与两个系统进行比较。实验结果表明，ShortTail最高可降低63.77%的99分位延迟，且显著改善中位延迟和平均延迟。

关键词： 纠删码；内存存储系统；节点性能降级；小写请求；尾部延迟    

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Development of a steady thermal-hydraulic analysis code for the China Advanced Research Reactor

TIAN Wenxi, QIU Suizheng, GUO Yun, SU Guanghui, JIA Dounan, LIU Tiancai, ZHANG Jianwei

《能源前沿（英文）》 2007年 第1卷 第2期   页码 189-194 doi: 10.1007/s00000-007-0024-8

摘要： A multi-channel model steady-state thermal-hydraulic analysis code was developed for the China Advanced Research Reactor (CARR). By simulating the whole reactor core, the detailed mass flow distribution in the core was obtained. The result shows that structure size plays the most important role in mass flow distribution, and the influence of core power could be neglected under single-phase flow. The temperature field of the fuel element under unsymmetrical cooling condition was also obtained, which is necessary for further study such as stress analysis, etc. of the fuel element. At the same time, considering the hot channel effect including engineering factor and nuclear factor, calculation of the mean and hot channel was carried out and it is proved that all thermal-hydraulic parameters satisfy the Safety design regulation of CARR .

关键词： detailed     calculation     unsymmetrical     temperature     channel    

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Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

《机械工程前沿（英文）》 2011年 第6卷 第2期   页码 241-248 doi: 10.1007/s11465-011-0219-x

摘要：

This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.

关键词： load distribution     calculation method     pipe threaded connections     tension load    

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Comparison of optimal capacitor placement methods in radial distribution system with load growth andZIP load model

Veera Venkata Satya Naryana MURTY, Ashwani KUMAR

《能源前沿（英文）》 2013年 第7卷 第2期   页码 197-213 doi: 10.1007/s11708-013-0249-7

摘要： In this paper, a combined power loss sensitivity (PLS) index-based approach is proposed to determine the optimal location of the capacitors in the radial distribution system (RDS) based on the real and reactive combined loss sensitivity index, as capacitor placement not only reduces real power loss with voltage profile improvement but also reduces reactive power loss due to the reactive power compensation in the network. The results have been obtained with the existing methods of power loss index (PLI) and index vector (IV) method for comparison. Besides, the optimal placement has been obtained with the proposed method as well as existing methods and the total kVar support has been obtained. In addition, the results of net cost savings for the 10-, 34-, and 69-bus systems are obtained for comparison. Moreover, the results have been obtained for a large system of 85 buses to validate the results with combined sensitivity based approach. Furthermore, the load growth factor has been considered in the study which is essential for the planning and expansion of the existing systems, whereas the impact of the realistic load model as ZIP load model has been considered for the study of all the systems.

关键词： load growth     load models     reactive power compensation     radial distribution system     power loss index (PLI)     power loss sensitivity (PLS)     index vector (IV)    

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A practical multi-lane factor model of bridges based on multi-truck presence considering lane load disparities

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 877-894 doi: 10.1007/s11709-021-0756-2

摘要： Many bridge design specifications consider multi-lane factors (MLFs) a critical component of the traffic load model. Measured multi-lane traffic data generally exhibit significant lane disparities in traffic loads over multiple lanes. However, these disparities are not considered in current specifications. To address this drawback, a multi-coefficient MLF model was developed based on an improved probabilistic statistical approach that considers the presence of multiple trucks. The proposed MLF model and approach were calibrated and demonstrated through an example site. The model sensitivity analysis demonstrated the significant influence of lane disparity of truck traffic volume and truck weight distribution on the MLF. Using the proposed approach, the experimental site study yielded MLFs comparable with those directly calculated using traffic load effects. The exclusion of overloaded trucks caused the proposed approach, existing design specifications, and conventional approach of ignoring lane load disparity to generate comparable MLFs, while the MLFs based on the proposed approach were the most comprehensive. The inclusion of overloaded trucks caused the conventional approach and design specifications to overestimate the MLFs significantly. Finally, the benefits of the research results to bridge practitioners were discussed.

关键词： bridges     multi-lane factor     traffic load     lane load disparity     multi-truck presence     weigh-in-motion data    

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Shape design of arch dams under load uncertainties with robust optimization

Fengjie TAN, Tom LAHMER

《结构与土木工程前沿（英文）》 2019年 第13卷 第4期   页码 852-862 doi: 10.1007/s11709-019-0522-x

摘要： Due to an increased need in hydro-electricity, water storage, and flood protection, it is assumed that a series of new dams will be build throughout the world. The focus of this paper is on the non-probabilistic-based design of new arch-type dams by applying means of robust design optimization (RDO). This type of optimization takes into account uncertainties in the loads and in the material properties of the structure. As classical procedures of probabilistic-based optimization under uncertainties, such as RDO and reliability-based design optimization (RBDO), are in general computationally expensive and rely on estimates of the system’s response variance, we will not follow a full-probabilistic approach but work with predefined confidence levels. This leads to a bi-level optimization program where the volume of the dam is optimized under the worst combination of the uncertain parameters. As a result, robust and reliable designs are obtained and the result is independent from any assumptions on stochastic properties of the random variables in the model. The optimization of an arch-type dam is realized here by a robust optimization method under load uncertainty, where hydraulic and thermal loads are considered. The load uncertainty is modeled as an ellipsoidal expression. Comparing with any traditional deterministic optimization method, which only concerns the minimum objective value and offers a solution candidate close to limit-states, the RDO method provides a robust solution against uncertainty. To reduce the computational cost, a ranking strategy and an approximation model are further involved to do a preliminary screening. By this means, the robust design can generate an improved arch dam structure that ensures both safety and serviceability during its lifetime.

关键词： arch dam     shape optimization     robust optimization     load uncertainty     approximation model    

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Prediction of bed load sediments using different artificial neural network models

Reza ASHEGHI, Seyed Abbas HOSSEINI

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 374-386 doi: 10.1007/s11709-019-0600-0

摘要： Modeling and prediction of bed loads is an important but difficult issue in river engineering. The introduced empirical equations due to restricted applicability even in similar conditions provide different accuracies with each other and measured data. In this paper, three different artificial neural networks (ANNs) including multilayer percepterons, radial based function (RBF), and generalized feed forward neural network using five dominant parameters of bed load transport formulas for the Main Fork Red River in Idaho-USA were developed. The optimum models were found through 102 data sets of flow discharge, flow velocity, water surface slopes, flow depth, and mean grain size. The deficiency of empirical equations for this river by conducted comparison between measured and predicted values was approved where the ANN models presented more consistence and closer estimation to observed data. The coefficient of determination between measured and predicted values for empirical equations varied from 0.10 to 0.21 against the 0.93 to 0.98 in ANN models. The accuracy performance of all models was evaluated and interpreted using different statistical error criteria, analytical graphs and confusion matrixes. Although the ANN models predicted compatible outputs but the RBF with 79% correct classification rate corresponding to 0.191 network error was outperform than others.

关键词： bed load prediction     artificial neural network     modeling     empirical equations    

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标题 作者 时间 类型 操作

An approach to calculating allowable watershed pollutant loads

Yu GUO, Haifeng JIA

期刊论文

Experimental study of wind loads on gable roofs of low-rise buildings with overhangs

Peng HUANG, Ling TAO, Ming GU, Yong QUAN

期刊论文

Optimization of spatial structure designs of control rod using Monte Carlo code RMC

期刊论文

Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

期刊论文

EAI-oriented information classification code system in manufacturing enterprises

WANG Junbiao, DENG Hu, JIANG Jianjun, YANG Binghong, WANG Bailing

期刊论文

A MATLAB code for the material-field series-expansion topology optimization method

期刊论文

基于近似子树匹配的快速代码推荐方法

邵宜超1,2,3,黄志球1,2,3,李伟湋1,2,3,喻垚慎1,2,3

期刊论文

代码变更驱动的增量式软件架构恢复技术

王丽1,2,孔祥龙1,王家慧3,李必信1

期刊论文

ShortTail：降低纠删码内存存储系统的尾部延迟

滕云1,3,李之悦2,4,黄晶1,3,张广艳2,4

期刊论文

Development of a steady thermal-hydraulic analysis code for the China Advanced Research Reactor

TIAN Wenxi, QIU Suizheng, GUO Yun, SU Guanghui, JIA Dounan, LIU Tiancai, ZHANG Jianwei

期刊论文

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

期刊论文

Comparison of optimal capacitor placement methods in radial distribution system with load growth andZIP load model

Veera Venkata Satya Naryana MURTY, Ashwani KUMAR

期刊论文

A practical multi-lane factor model of bridges based on multi-truck presence considering lane load disparities

期刊论文

Shape design of arch dams under load uncertainties with robust optimization

Fengjie TAN, Tom LAHMER

期刊论文

Prediction of bed load sediments using different artificial neural network models

Reza ASHEGHI, Seyed Abbas HOSSEINI

期刊论文