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BDS/GPS双系统定轨 1

BDS码偏差 1

NOx 1

低轨卫星精密定轨 1

数据流;多维序列;异常检测;概念漂移;特征选择 1

星载BDS/GPS 1

浓淡燃烧 1

漂移性 1

燃烧器 1

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计算机仿真实验 1

锅炉 1

非线性状态空间模型;测量值偏差;扩展卡尔曼滤波;扩展卡尔曼平滑;最大期望算法 1

风云-3C 1

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A combined modulated feedback and temperature compensation approach to improve bias drift of a closed-loop

Ming-jun MA,Zhong-he JIN,Hui-jie ZHU

《信息与电子工程前沿(英文)》 2015年 第16卷 第6期   页码 497-510 doi: 10.1631/FITEE.1400349

摘要: The bias drift of a micro-electro-mechanical systems (MEMS) accelerometer suffers from the 1/ noise and the temperature effect. For massive applications, the bias drift urgently needs to be improved. Conventional methods often cannot address the 1/ noise and temperature effect in one architecture. In this paper, a combined approach on closed-loop architecture modification is proposed to minimize the bias drift. The modulated feedback approach is used to isolate the 1/ noise that exists in the conventional direct feedback approach. Then a common mode signal is created and added into the closed loop on the basis of modulated feedback architecture, to compensate for the temperature drift. With the combined approach, the bias instability is improved to less than 13 μ , and the drift of the Allan variance result is reduced to 17 μ at 100 s of the integration time. The temperature coefficient is reduced from 4.68 to 0.1 m /°C. The combined approach could be useful for many other closed-loop accelerometers.

关键词: Bias drift     Closed-loop MEMS accelerometer     Modulated feedback approach     Temperature compensation    

Controlling interstory drift ratio profiles via topology optimization strategies

《结构与土木工程前沿(英文)》 2023年 第17卷 第2期   页码 165-178 doi: 10.1007/s11709-022-0892-3

摘要: An approach to control the profiles of interstory drift ratios along the height of building structures via topology optimization is proposed herein. The theoretical foundation of the proposed approach involves solving a min–max optimization problem to suppress the maximum interstory drift ratio among all stories. Two formulations are suggested: one inherits the bound formulation and the other utilizes a p-norm function to aggregate all individual interstory drift ratios. The proposed methodology can shape the interstory drift ratio profiles into inverted triangular or quadratic patterns because it realizes profile control using a group of shape weight coefficients. The proposed formulations are validated via a series of numerical examples. The disparity between the two formulations is clear. The optimization results show the optimal structural features for controlling the interstory drift ratios under different requirements.

关键词: interstory drift ratio     aggregation function     bound formulation     min–max problem     topology optimization    

Enhanced empirical models for predicting the drift capacity of less ductile RC columns with flexural,

Mohammad Reza AZADI KAKAVAND, Reza ALLAHVIRDIZADEH

《结构与土木工程前沿(英文)》 2019年 第13卷 第5期   页码 1251-1270 doi: 10.1007/s11709-019-0554-2

摘要: Capacity of components subjected to earthquake actions is still a widely interesting research topic. Hence, developing precise tools for predicting drift capacities of reinforced concrete (RC) columns is of great interest. RC columns are not only frequently constructed, but also their composite behavior makes the capacity prediction a task faced with many uncertainties. In the current article, novel empirical approaches are presented for predicting flexural, shear and axial failure modes in RC columns. To this aim, an extensive experimental database was created by collecting outcomes of previously conducted experimental tests since 1964, which are available in the literature. It serves as the basis for deriving the equations for predicting the drift capacity of RC columns by different regression analyses (both linear with different orders and nonlinear). Furthermore, fragility curves are determined for comparing the obtained results with the experimental results and with previously proposed models, like the ones of ASCE/SEI 41-13. It is demonstrated that the proposed equations predict drift capacities, which are in better agreement with experimental results than those computed by previously published models. In addition, the reliability of the proposed equations is higher from a probabilistic point of view.

关键词: flexural-shear-axial failure     drift capacity     reinforced concrete columns     statistical analysis     fragility curves    

Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Lili CHEN, Wu ZHOU

《机械工程前沿(英文)》 2013年 第8卷 第2期   页码 146-149 doi: 10.1007/s11465-013-0260-z

摘要:

To predict more precisely the frequency of force-balanced micro accelerometer with different bias voltages, the effects of bias voltages on error sensitivity of frequency is studied. The resonance frequency of accelerometer under closed loop control is derived according to its operation principle, and its error sensitivity is derived and analyzed under over etching structure according to the characteristics of Deep Reaction Ion Etching (DRIE). Based on the theoretical results, micro accelerometer is fabricated and tested to study the influences of AC bias voltage and DC bias voltage on sensitivity, respectively. Experimental results indicate that the relative errors between test data and theory data are less than 7%, and the fluctuating value of error sensitivity under the range of voltage adjustment is less than 0.01 μm . It is concluded that the error sensitivity with designed parameters of structure, circuit and process error can be used to predict the frequency of accelerometer with no need to consider the influence of bias voltage.

关键词: Micro-Electro-Mechanical Systems (MEMS)     micro accelerometer     force-balanced micro accelerometer     frequency     error sensitivity    

单一方法评价结论漂移性的测度研究

陈国宏,李美娟,陈衍泰

《中国工程科学》 2004年 第6卷 第3期   页码 58-63

摘要:

主要研究单一方法评价结论的漂移性,以便为组合评价提供实验依据。把现实评价问题分为3大类分别进行仿真实验,利用MATLAB生成待评价对象,利用不同方法进行评价,把评价结果进行标准化处理,并判别评价方法的相容性,以相容方法的平均值为参照系,求各评价方法的漂移度。

关键词: 综合评价方法     计算机仿真实验     漂移性    

A method for quantifying bias in modeled concentrations and source impacts for secondary particulate

Cesunica E. Ivey, Heather A. Holmes, Yongtao Hu, James A. Mulholland, Armistead G. Russell

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0866-6

摘要: A method for quantifying source impacts for secondary PM species is derived. The method provides estimates of bias in modeled concentrations. Adjusted concentrations match corresponding observations at monitored locations. Sources impacts on secondary species are estimated over the US for 20 sources. Community Multi-Scale Air Quality (CMAQ) estimates of sulfates, nitrates, ammonium, and organic carbon are highly influenced by uncertainties in modeled secondary formation processes, such as chemical mechanisms, volatilization, and condensation rates. These compounds constitute the majority of PM mass, and reducing bias in estimated concentrations has benefits for policy measures and epidemiological studies. In this work, a method for adjusting source impacts on secondary species is developed that provides estimates of source contributions and reduces bias in modeled concentrations compared to observations. The bias correction adjusts concentrations and source impacts based on the difference between modeled concentrations and observations while taking into account uncertainties at the location of interest; and it is applied both spatially and temporally. We apply the method over the US for 2006. The mean bias for initial CMAQ concentrations compared to observations is −0.28 (OC), 0.11 (NO ), 0.05 (NH ), and −0.08 (SO ). The normalized mean bias in modeled concentrations compared to observations was effectively zero for OC, NO , NH , and SO after applying the secondary bias correction. 10-fold cross-validation was conducted to determine the performance of the spatial application of the bias correction. Cross-validation performance was favorable; correlation coefficients were greater than 0.69 for all species when comparing observations and concentrations based on kriged correction factors. The methods presented here address model uncertainties by improving simulated concentrations and source impacts of secondary particulate matter through data assimilation. Secondary-adjusted concentrations and source impacts from 20 emissions sources are generated for 2006 over continental US.

关键词: Particulate matter     Source apportionment     Secondary particulate matter     Chemical transport modeling     Receptor modeling    

Common biases in client involved decision-making in the AEC industry

Sujesh F. SUJAN, Arto KIVINIEMI, Steve W. JONES, Jacqueline M. WHEATHCROFT, Eilif HJELSETH

《工程管理前沿(英文)》 2019年 第6卷 第2期   页码 221-238 doi: 10.1007/s42524-019-0026-3

摘要: Understanding of the constitution of client involved decisions is important for future improvements of the processes. Significant decisions in construction projects are reliant on heuristic processes where assumptions are developed from past experience. The paper presents a methodology to collect empirical data in an unstructured manner utilizing participant intuition and experience regarding project level collaboration, a term easily understood by practitioners. Empirical data collected from 6 focus group discussions in Norway and 18 individual interviews in Finland is associated with biases in decision making aimed at bridging the gap of understanding and literature’s insufficient coverage. An analytic framework was developed to suit the diverse emergence of concepts to allow application of psychological principles in a structured manner to empirical data. The paper contributes by identifying types of cognitive and motivational biases in client involved decisions. The biases are found to be alleviated by one another depending on the particular application of the decision. Findings suggest that normative beliefs exist developed from past experience and habitual thinking. A number of emerged biases in this domain are alleviated from normative beliefs which are discussed in this paper.

关键词: collaboration     construction industry     social science     decision-making     client     cognitive bias     motivational bias     holistic analysis     human factor    

Anensemble method for data stream classification in the presence of concept drift

Omid ABBASZADEH,Ali AMIRI,Ali Reza KHANTEYMOORI

《信息与电子工程前沿(英文)》 2015年 第16卷 第12期   页码 1059-1068 doi: 10.1631/FITEE.1400398

摘要: One recent area of interest in computer science is data stream management and processing. By ‘data stream’, we refer to continuous and rapidly generated packages of data. Specific features of data streams are immense volume, high production rate, limited data processing time, and data concept drift; these features differentiate the data stream from standard types of data. An issue for the data stream is classification of input data. A novel ensemble classifier is proposed in this paper. The classifier uses base classifiers of two weighting functions under different data input conditions. In addition, a new method is used to determine drift, which emphasizes the precision of the algorithm. Another characteristic of the proposed method is removal of different numbers of the base classifiers based on their quality. Implementation of a weighting mechanism to the base classifiers at the decision-making stage is another advantage of the algorithm. This facilitates adaptability when drifts take place, which leads to classifiers with higher efficiency. Furthermore, the proposed method is tested on a set of standard data and the results confirm higher accuracy compared to available ensemble classifiers and single classifiers. In addition, in some cases the proposed classifier is faster and needs less storage space.

关键词: Data stream     Classificaion     Ensemble classifiers     Concept drift    

Behaviour of self-centring shear walls——A state of the art review

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 53-77 doi: 10.1007/s11709-022-0850-0

摘要: The application of unbonded post-tensioning (PT) in structural walls has led to the development of advanced self-centring (rocking) shear wall systems that has significant advantages, including accelerated construction due to the incorporation of prefabricated elements and segmental construction for different materials (e.g., concrete, masonry, and timber), reduced residual drifts, and little damage upon extreme seismic and wind loads. Concrete, masonry, and timber are often used for the construction of unbonded PT structural wall systems. Despite extensive research since the 1980s, there are no well-established design guidelines available on the shear wall configuration with the required energy dissipation system, joint’s locations and acceptance criteria for shear sliding, confinement, seismic performance factors, PT loss, PT force range and residual drifts of shear walls subjected to lateral loads. In this research a comprehensive state-of-the-art literature review was performed on self-centring shear wall system. An extensive study was carried out to collect a database of 100 concrete, masonry, and self-centring shear wall tests from the literature. The established database was then used to review shear walls’ configurations, material, and components to benchmark requirements applicable for design purposes. The behaviour of concrete, masonry and timber shear walls were compared and critically analysed. The general behaviour, force-displacement performance of the walls, ductility, and seismic response factors, were critically reviewed and analysed for different self-centring wall systems to understand the effect of different parameters including configurations of the walls, material used for construction of the wall (concrete, masonry, timber) and axial stress ratio. The outcome of this research can be used to better understand the behaviour of self-centring wall system in order to develop design guidelines for such walls.

关键词: self-centring shear walls     rocking walls     energy dissipation     seismic performance factors     PT loss     residual drift    

风包粉系列浓淡煤粉燃烧技术的研究

秦裕琨,李争起,孙锐,陈力哲,孙绍增,朱群益,李瑞扬,高继慧,吴少华

《中国工程科学》 2002年 第4卷 第11期   页码 42-49

摘要:

总结了哈尔滨工业大学15年来对浓淡煤粉燃烧技术的研究成果,阐述了浓淡煤粉燃烧技术的原理及所具有的风包粉流动特点,并通过工业试验验证了风包粉原理。针对我国电站锅炉燃煤的特点,提出了需要解决的5个问题,指出了浓淡燃烧技术的发展方向。

关键词: 锅炉     燃烧器     浓淡燃烧     NOx    

Social media and mobility landscape: Uncovering spatial patterns of urban human mobility with multi source data

Yilan Cui, Xing Xie, Yi Liu

《环境科学与工程前沿(英文)》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1068-1

摘要:

Check-in and survey data are explored to identify personal activity-specific places.

Ways for detecting and moderating sample bias of Weibo check-in data is proposed.

A graphic representation of urban activity intensity in Beijing, China is presented.

The potential application of Weibo check-in data for urban analysis is introduced.

关键词: Social media     Human mobility     Population bias     Sample reconstruction     Data integration    

Seismic fragility assessment of revised MRT buildings considering typical construction changes

Rakesh DUMARU, Hugo RODRIGUES, Humberto VARUM

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 241-266 doi: 10.1007/s11709-019-0560-4

摘要: The present study investigates the vulnerability assessment of the prototype revised Mandatory Rule of Thumb (MRT) buildings initially designed and detailed for three storeys bare frame building; later modified through variable number of storeys (three, four, and five) and different arrangement of infill walls (bare frame, soft-storey, irregular infilled, and fully infilled). The application of infill walls increases the fundamental frequencies, stiffness, and maximum strength capacity, but reduces the deformation capability than the bare frame building. The vulnerability was also reduced through infill walls, where the probability of exceeding partial-collapse and collapse damage reduced by 80% and 50%, respectively. Furthermore, the increased in storeys (three to five) also increases the failure probability, such that partial-collapse and collapse for fully infilled increases by almost 55% and 80%, respectively. All obtained results and discussions concluded that the structural sections and details assigned for MRT building is not sufficient if considered as bare frame and soft-storey. And increase in number of storeys causes building highly vulnerable although the infill walls were considered.

关键词: mid-rise buildings     revised NBC 205: 2012     masonry infill walls     configurations of infill walls     vulnerability assessment and inter-storey drift    

Same stimuli, different responses: a pilot study assessing air pollution visibility impacts on emotional well-being in a controlled environment

《环境科学与工程前沿(英文)》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1620-5

摘要:

● Emotional responses to visibility-reducing haze was assessed in a controlled lab.

关键词: Air pollution     Emotional wellbeing     Variability     Visual exposure     Emotional bias    

针对目标跟踪的两种基于最大期望算法测量值偏差估计过程的性能分析 None

Zhi-hua LU, Meng-yao ZHU, Qing-wei YE, Yu ZHOU

《信息与电子工程前沿(英文)》 2018年 第19卷 第9期   页码 1151-1165 doi: 10.1631/FITEE.1800214

摘要: 在现实目标跟踪问题中,传感器采集的测量值,比如系统缺陷,可能存在一定程度偏差。为正确估计目标的运动轨迹,测量值偏差的识别与估计将成为首要任务。首先,提出两种状态空间模型,分别把测量值偏差视为随机变量和常数。其次,假设测量值样本数足够大,基于最大期望算法,利用扩展卡尔曼滤波和平滑,针对两种模型提出不同的循环迭代偏差估计过程。最后,分析这两种估计过程的全局收敛结果,揭示其内在联系。结果表明,第二种估计过程比第一种估计过程更简单准确,并且收敛速度更快。批量处理测量值样本后,可同时获得目标运动轨迹和测量值偏差的估计结果。

关键词: 非线性状态空间模型;测量值偏差;扩展卡尔曼滤波;扩展卡尔曼平滑;最大期望算法    

Impact of crude distillation unit model accuracy on refinery production planning

Gang FU, Pedro A. Castillo CASTILLO, Vladimir MAHALEC

《工程管理前沿(英文)》 2018年 第5卷 第2期   页码 195-201 doi: 10.15302/J-FEM-2017052

摘要: In this work, we examine the impact of crude distillation unit (CDU) model errors on the results of refinery-wide optimization for production planning or feedstock selection. We compare the swing cut+ bias CDU model with a recently developed hybrid CDU model (Fu et al., 2016). The hybrid CDU model computes material and energy balances, as well as product true boiling point (TBP) curves and bulk properties (e.g., sulfur % and cetane index, and other properties). Product TBP curves are predicted with an average error of 0.5% against rigorous simulation curves. Case studies of optimal operation computed using a planning model that is based on the swing cut+ bias CDU model and using a planning model that incorporates the hybrid CDU model are presented. Our results show that significant economic benefits can be obtained using accurate CDU models in refinery production planning.

关键词: impact of model accuracy on production planning     swing cut+ bias CDU model     hybrid CDU model     refinery feedstock selection optimization     optimization of refinery operation    

标题 作者 时间 类型 操作

A combined modulated feedback and temperature compensation approach to improve bias drift of a closed-loop

Ming-jun MA,Zhong-he JIN,Hui-jie ZHU

期刊论文

Controlling interstory drift ratio profiles via topology optimization strategies

期刊论文

Enhanced empirical models for predicting the drift capacity of less ductile RC columns with flexural,

Mohammad Reza AZADI KAKAVAND, Reza ALLAHVIRDIZADEH

期刊论文

Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Lili CHEN, Wu ZHOU

期刊论文

单一方法评价结论漂移性的测度研究

陈国宏,李美娟,陈衍泰

期刊论文

A method for quantifying bias in modeled concentrations and source impacts for secondary particulate

Cesunica E. Ivey, Heather A. Holmes, Yongtao Hu, James A. Mulholland, Armistead G. Russell

期刊论文

Common biases in client involved decision-making in the AEC industry

Sujesh F. SUJAN, Arto KIVINIEMI, Steve W. JONES, Jacqueline M. WHEATHCROFT, Eilif HJELSETH

期刊论文

Anensemble method for data stream classification in the presence of concept drift

Omid ABBASZADEH,Ali AMIRI,Ali Reza KHANTEYMOORI

期刊论文

Behaviour of self-centring shear walls——A state of the art review

期刊论文

风包粉系列浓淡煤粉燃烧技术的研究

秦裕琨,李争起,孙锐,陈力哲,孙绍增,朱群益,李瑞扬,高继慧,吴少华

期刊论文

Social media and mobility landscape: Uncovering spatial patterns of urban human mobility with multi source data

Yilan Cui, Xing Xie, Yi Liu

期刊论文

Seismic fragility assessment of revised MRT buildings considering typical construction changes

Rakesh DUMARU, Hugo RODRIGUES, Humberto VARUM

期刊论文

Same stimuli, different responses: a pilot study assessing air pollution visibility impacts on emotional well-being in a controlled environment

期刊论文

针对目标跟踪的两种基于最大期望算法测量值偏差估计过程的性能分析

Zhi-hua LU, Meng-yao ZHU, Qing-wei YE, Yu ZHOU

期刊论文

Impact of crude distillation unit model accuracy on refinery production planning

Gang FU, Pedro A. Castillo CASTILLO, Vladimir MAHALEC

期刊论文