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新冠病毒肺炎疫苗分配 ——模拟可替代策略的健康结局和公正性影响 Article

Maddalena Ferranna, Daniel Cadarette, David E. Bloom

《工程（英文）》 2021年第7卷第7期页码 924-935 doi: 10.1016/j.eng.2021.03.014

摘要：

鉴于缺乏安全有效的新冠病毒肺炎（COVID-19）疫苗，一个主要的政策问题是如何在不同的社会人口学特征群体中分配疫苗。本文评估了迄今为止提出的COVID-19疫苗优先策略，重点关注其既定目标；所选分配方案对于大流行病进程和负担的影响机制；以及制定优先策略时出现的流行病学、经济、后勤和政治等主要问题。本文将一个简洁、按年龄分层的易感-暴露-感染-恢复模型应用于美国，以定量评估替代优先策略在保护死亡、保护感染和延长寿命方面的表现。我们证明了优先考虑重点岗位人群是减少病例数量和降低死亡损失生命年的可行策略，而在大多数情况下，通过优先考虑老年人来实现死亡人数的最大减少，即使疫苗能有效阻止病毒传播。这一特性的不确定性和疫苗针剂支付的潜在延迟加强了优先考虑老年人的呼吁。此外，我们还调查了支持分配策略的公平动机的强度，该策略将绝对优先考虑给予重点岗位人群能降低感染致死风险的疫苗。

关键词：疫苗分配 COVID-19 公正性 SEIR模型

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临床诊断标准实施和全城症状排查对武汉新冠病毒肺炎疫情防控的效果评价 Article

魏永越, 魏良敏, 姜玥, 沈思鹏, 赵杨, 郝元涛, 杜志成, 唐金陵, 张志杰, 姜庆五, 李立明, 陈峰, 沈洪兵

《工程（英文）》 2020年第6卷第10期页码 1141-1146 doi: 10.1016/j.eng.2020.04.008

摘要：考虑COVID-19的传播机理、隔离措施等，建立SEIR^+Q传播动力学模型。

关键词： COVID-19 SEIR+Q传染病动力学模型临床诊断标准全城症状排查干预效果评价

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Estimation of reproduction numbers of COVID-19 in typical countries and epidemic trends under different prevention and control scenarios

Chen Xu, Yinqiao Dong, Xiaoyue Yu, Huwen Wang, Lhakpa Tsamlag, Shuxian Zhang, Ruijie Chang, Zezhou Wang, Yuelin Yu, Rusi Long, Ying Wang, Gang Xu, Tian Shen, Suping Wang, Xinxin Zhang, Hui Wang, Yong Cai

《医学前沿（英文）》 2020年第14卷第5期页码 613-622 doi: 10.1007/s11684-020-0787-4

摘要： The coronavirus disease 2019 (COVID-19) has become a life-threatening pandemic. The epidemic trends in different countries vary considerably due to different policy-making and resources mobilization. We calculated basic reproduction number (R ) and the time-varying estimate of the effective reproductive number (R ) of COVID-19 by using the maximum likelihood method and the sequential Bayesian method, respectively. European and North American countries possessed higher R and unsteady R fluctuations, whereas some heavily affected Asian countries showed relatively low R and declining R now. The numbers of patients in Africa and Latin America are still low, but the potential risk of huge outbreaks cannot be ignored. Three scenarios were then simulated, generating distinct outcomes by using SEIR (susceptible, exposed, infectious, and removed) model. First, evidence-based prompt responses yield lower transmission rate followed by decreasing R . Second, implementation of effective control policies at a relatively late stage, in spite of huge casualties at early phase, can still achieve containment and mitigation. Third, wisely taking advantage of the time-window for developing countries in Africa and Latin America to adopt adequate measures can save more people’s life. Our mathematical modeling provides evidence for international communities to develop sound design of containment and mitigation policies for COVID-19.

关键词： reproduction number SEIR model COVID-19 estimate

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Phase- and epidemic region-adjusted estimation of the number of coronavirus disease 2019 cases in China

Ruijie Chang, Huwen Wang, Shuxian Zhang, Zezhou Wang, Yinqiao Dong, Lhakpa Tsamlag, Xiaoyue Yu, Chen Xu, Yuelin Yu, Rusi Long, Ning-Ning Liu, Qiao Chu, Ying Wang, Gang Xu, Tian Shen, Suping Wang, Xiaobei Deng, Jinyan Huang, Xinxin Zhang, Hui Wang, Yong Cai

《医学前沿（英文）》 2020年第14卷第2期页码 199-209 doi: 10.1007/s11684-020-0768-7

摘要： The outbreak of the coronavirus disease 2019 was first reported in Wuhan in December 2019 and gradually spread to other areas in China. After implementation of prevention and control measures, the estimation of the epidemic trend is needed. A phase- and region-adjusted SEIR model was applied for modeling and predicting the number of cases in Wuhan, Hubei Province and regions outside Hubei Province in China. The estimated number of infections could reach its peak in late February 2020 in Wuhan and Hubei Province, which is 55 303–84 520 and 83 944–129 312, respectively, while the epidemic peaks in regions outside Hubei Province in China could appear on February 13, 2020 with the estimated 13 035–19 108 cases. According to the estimation, the outbreak would abate in March and April all over China. Current estimation provided evidence for planned work resumption under stringent prevention and control in China to further support the fight against the epidemic. Nevertheless, there is still possibility of the second outbreak brought by the work resumption and population migration, especially from Hubei Province and high intensity cities outside Hubei Province. Strict prevention and control measures still need to be considered in the regions with high intensity of epidemic and densely-populated cities.

关键词： SEIR model COVID-19 estimate China

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Standard model of knowledge representation

Wensheng YIN

《机械工程前沿（英文）》 2016年第11卷第3期页码 275-288 doi: 10.1007/s11465-016-0372-3

摘要：

Knowledge representation is the core of artificial intelligence research. Knowledge representation methods include predicate logic, semantic network, computer programming language, database, mathematical model, graphics language, natural language, etc. To establish the intrinsic link between various knowledge representation methods, a unified knowledge representation model is necessary. According to ontology, system theory, and control theory, a standard model of knowledge representation that reflects the change of the objective world is proposed. The model is composed of input, processing, and output. This knowledge representation method is not a contradiction to the traditional knowledge representation method. It can express knowledge in terms of multivariate and multidimensional. It can also express process knowledge, and at the same time, it has a strong ability to solve problems. In addition, the standard model of knowledge representation provides a way to solve problems of non-precision and inconsistent knowledge.

关键词： knowledge representation standard model ontology system theory control theory multidimensional representation

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张正彦：融合知识的预训练语言模型（2020年4月3日）

2022年04月18日

关键词：工程管理

受限空间火灾模型研究进展

郑昕,袁宏永

《中国工程科学》 2004年第6卷第3期页码 68-74

摘要：

火灾模型是从工程科学的角度出发，分析研究火灾的发生、发展，烟气蔓延以及火灾对周围环境诸如建筑设备、森林植被及大气环境等影响的数学模型。介绍了广泛应用于建筑物内部受限空间的场、区域、网模型以及经验模型的理论思想与数学方程，分析了4种模型在相应环境下应用的合理性，并对火灾模型的发展做出了展望。

关键词：受限空间场模型区域模型网模型场区网模型经验模型

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Elevated temperature creep model of parallel wire strands

《结构与土木工程前沿（英文）》页码 1060-1071 doi: 10.1007/s11709-023-0981-y

摘要： Parallel wire strands (PWSs), which are widely used in prestressed steel structures, are typically in high-stress states. Under fire conditions, significant creep effects occur, reducing the prestress and influencing the mechanical behavior of PWSs. As there is no existing approach to analyze their creep behavior, this study experimentally investigated the elevated temperature creep model of PWSs. A charge-coupled camera system was incorporated to accurately obtain the deformation of the specimen during the elevated temperature creep test. It was concluded that the temperature level had a more significant effect on the creep strain than the stress level, and 450 °C was the key segment point where the creep rate varied significantly. By comparing the elevated temperature creep test results for PWSs and steel strands, it was found that the creep strain of PWSs was lower than that of steel strands at the same temperature and stress levels. The parameters in the general empirical formula, the Bailey–Norton model, and the composite time-hardening model were fitted based on the experimental results. By evaluating the accuracy and form of the models, the composite time-hardening model, which can simultaneously consider temperature, stress, and time, is recommended for use in the fire-resistance design of pre-tensioned structures with PWSs.

关键词： parallel wire strands experimental study elevated temperature creep model

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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

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Test-driven verification/validation of model transformations

László LENGYEL,Hassan CHARAF

《信息与电子工程前沿（英文）》 2015年第16卷第2期页码 85-97 doi: 10.1631/FITEE.1400111

摘要： Why is it important to verify/validate model transformations? The motivation is to improve the quality of the transformations, and therefore the quality of the generated software artifacts. Verified/validated model transformations make it possible to ensure certain properties of the generated software artifacts. In this way, verification/validation methods can guarantee different requirements stated by the actual domain against the generated/modified/optimized software products. For example, a verified/validated model transformation can ensure the preservation of certain properties during the model-to-model transformation. This paper emphasizes the necessity of methods that make model transformation verified/validated, discusses the different scenarios of model transformation verification and validation, and introduces the principles of a novel test-driven method for verifying/validating model transformations. We provide a solution that makes it possible to automatically generate test input models for model transformations. Furthermore, we collect and discuss the actual open issues in the field of verification/validation of model transformations.

关键词： Graph rewriting based model transformations Verification/validation Test-driven verification

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Digital twin-assisted gearbox dynamic model updating toward fault diagnosis

《机械工程前沿（英文）》 2023年第18卷第2期 doi: 10.1007/s11465-023-0748-0

摘要： One of the core challenges of intelligent fault diagnosis is that the diagnosis model requires numerous labeled training datasets to achieve satisfactory performance. Generating training data using a virtual model is a potential solution for addressing such a problem, and the construction of a high-fidelity virtual model is fundamental and critical for data generation. In this study, a digital twin-assisted dynamic model updating method for fault diagnosis is thus proposed to improve the fidelity and reliability of a virtual model, which can enhance the generated data quality. First, a virtual model is established to mirror the vibration response of a physical entity using a dynamic modeling method. Second, the modeling method is validated through a frequency analysis of the generated signal. Then, based on the signal similarity indicator, a physical–virtual signal interaction method is proposed to dynamically update the virtual model in which parameter sensitivity analysis, surrogate technique, and optimization algorithm are applied to increase the efficiency during the model updating. Finally, the proposed method is successfully applied to the dynamic model updating of a single-stage helical gearbox; the virtual data generated by this model can be used for gear fault diagnosis.

关键词： digital twin gearbox model construction model updating physical–virtual interaction

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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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Initiation of Setaria as a model plant

Xianmin DIAO,James SCHNABLE,Jeffrey L. BENNETZEN,Jiayang LI

《农业科学与工程前沿（英文）》 2014年第1卷第1期页码 16-20 doi: 10.15302/J-FASE-2014011

摘要： Model organisms such as Arabidopsis ( ) and rice ( ) have proven essential for efficient scientific discovery and development of new methods. With the diversity of plant lineages, some important processes such as C photosynthesis are not found in either Arabidopsis or rice, so new model species are needed. Due to their small diploid genomes, short life cycles, self-pollination, small adult statures and prolific seed production, domesticated foxtail millet ( ) and its wild ancestor, green foxtail ( ), have recently been proposed as novel model species for functional genomics of the Panicoideae, especially for study of C photosynthesis. This review outlines the development of these species as model organisms, and discusses current challenges and future potential of a Setaria model.

关键词： Setaria foxtail millet C₄ photosynthesis model organism

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A time−space porosity computational model for concrete under sulfate attack

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0985-7

摘要： The deterioration of the microscopic pore structure of concrete under external sulfate attack (ESA) is a primary cause of degradation. Nevertheless, little effort has been invested in exploring the temporal and spatial development of the porosity of concrete under ESA. This study proposes a mechanical–chemical model to simulate the spatiotemporal distribution of the porosity. A relationship between the corrosion damage and amount of ettringite is proposed based on the theory of volume expansion. In addition, the expansion strain at the macro-scale is obtained using a stress analysis model of composite concentric sphere elements and the micromechanical mean-field approach. Finally, considering the influence of corrosion damage and cement hydration on the diffusion of sulfate ions, the expansion deformation and porosity space−time distribution are obtained using the finite difference method. The results demonstrate that the expansion strains calculated using the suggested model agree well with previously reported experimental results. Moreover, the tricalcium aluminate concentration, initial elastic modulus of cement paste, corrosion damage, and continuous hydration of cement significantly affect concrete under ESA. The proposed model can forecast and assess the porosity of concrete covers and provide a credible approach for determining the residual life of concrete structures under ESA.

关键词： expansion deformation porosity internal expansion stress external sulfate attack mechanical–chemical coupling model

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The Construction of Tetrahedral Model of Engineering Ethical Evaluation

Jin Wang

《工程管理前沿（英文）》 2014年第1卷第1期页码 62-70 doi: 10.15302/J-FEM-2014009

摘要： To achieve greatprojects, great attention should be attached to ethical issues of engineering. But endless immoralities in the field of engineering expose the lack of attention and the ineffectiveness of implementation of engineering ethical evaluation. The “Mirror” and the "Lamp" — these two metaphors used by M. H. Abrams vividly expose the differences in people's way of understanding which inspires author's study of the model of engineering ethical evaluation. With four elements of the project —artifact, engineer, user and environment, a tetrahedral model of integrity, strong restoring force and high stability is built. While their roles and responsibilities differ, each has to demonstrate a commitment to professional and ethical standards. In this model, four "Lamps" — i. e, four elements of engineering — in four corners provide light while four "Mirrors" — the result of reflection of four elements — reflect whether the tetrahedral model can truthfully evaluate the level of engineering ethics. The combination of the "Lamps" and "Mirrors" illuminates engineering ethical evaluation and leads to a plurality of evaluation standards, while simultaneously fostering both the avoidance of simple de-instrumentalization and the sustainability of ethical evaluation. Plurality of evaluation standards means the consideration of value differences in a multi-value state. The avoidance of de-instrumentalization means to prevent the engineer's expertise from fossilization. The sustainability of ethical evaluation accelerates the fulfillment of our dream, for the ultimate benefit of humankind. Ethical evaluation of the project not only helps more engineers to use expertise in pursuit of the public good, but also make more projects to meet people's short-term expectations and long-term cares.

关键词： tetrahedral model ethical evaluation engineering Lamps and Mirrors