Frontiers of Mechanical Engineering最新文献

Causal inference with a mediated proportional hazards regression model. 利用中介比例危险回归模型进行因果推断。

IF 0.9 2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2024-01-01 Epub Date: 2021-12-20 DOI: 10.1080/03610918.2021.2014887

Hui Zeng, Vernon M Chinchilli, Nasrollah Ghahramani

{"title":"Causal inference with a mediated proportional hazards regression model.","authors":"Hui Zeng, Vernon M Chinchilli, Nasrollah Ghahramani","doi":"10.1080/03610918.2021.2014887","DOIUrl":"10.1080/03610918.2021.2014887","url":null,"abstract":"<p><p>The natural direct and indirect effects in causal mediation analysis with survival data having one mediator is addressed by VanderWeele (2011) [1]. He derived an approach for (1) an accelerated failure time regression model in general cases and (2) a proportional hazards regression model when the time-to-event outcome is rare. If the outcome is not rare, then VanderWeele (2011) [1] did not derive a simple closed-form expression for the log-natural direct and log-natural indirect effects for the proportional hazards regression model because the baseline cumulative hazard function does not approach zero. We develop two approaches to extend VanderWeele's approach, in which the assumption of a rare outcome is not required. We obtain the natural direct and indirect effects for specific time points through numerical integration after we calculate the cumulative baseline hazard by (1) applying the Breslow method in the Cox proportional hazards regression model to estimate the unspecified cumulative baseline hazard; (2) assuming a piecewise constant baseline hazard model, yielding a parametric model, to estimate the baseline hazard and cumulative baseline hazard. We conduct simulation studies to compare our two approaches with other methods and illustrate our two approaches by applying them to data from the ASsessment, Serial Evaluation, and Subsequent Sequelae in Acute Kidney Injury (ASSESS-AKI) Consortium.</p>","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":"11 1","pages":"203-218"},"PeriodicalIF":0.9,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10760952/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74582045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Revolution and challenges in machining processing aimed at carbon reduction 以减碳为目标的机加工革命与挑战

IF 4.5 2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-12-02 DOI: 10.1007/s11465-023-0771-1

Changhe Li

引用次数: 0

Multi-material additive manufacturing-functionally graded materials by means of laser remelting during laser powder bed fusion 多材料增材制造--通过激光粉末床熔融过程中的激光重熔实现功能分级材料

IF 4.5 2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-12-01 DOI: 10.1007/s11465-023-0765-z

Alexander Schmidt, Felix Jensch, Sebastian Härtel

引用次数: 0

Review of key technologies of climbing robots 攀爬机器人关键技术综述

2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-11-10 DOI: 10.1007/s11465-023-0764-0

Ye Dai, Shikun Li, Xukun Rui, Chaofang Xiang, Xinlei Nie

引用次数: 0

A new modeling approach for stress–strain relationship taking into account strain hardening and stored energy by compacted graphite iron evolution 一种考虑应变硬化和压实石墨铁演化储存能量的应力应变关系建模新方法

2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-11-06 DOI: 10.1007/s11465-023-0761-3

Jiahui Niu, Chuanzhen Huang, Zhenyu Shi, Hanlian Liu, Zhengyi Tang, Binghao Li, Zhen Chen, Guoyan Jiang

引用次数: 0

Mechanical properties of vanadium-alloyed austempered ductile iron for crankshaft applications 曲轴用钒合金等温淬火球墨铸铁的力学性能

IF 4.5 2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-09-01 DOI: 10.1007/s11465-023-0746-2

Fatma Bayata, S. B. Vatan

引用次数: 0

Non-convex sparse optimization-based impact force identification with limited vibration measurements 有限振动条件下基于非凸稀疏优化的冲击力辨识

2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-09-01 DOI: 10.1007/s11465-023-0762-2

Lin Chen, Yanan Wang, Baijie Qiao, Junjiang Liu, Wei Cheng, Xuefeng Chen

引用次数: 0

Equipment-process-strategy integration for sustainable machining: a review 可持续加工的设备-工艺-策略集成研究综述

IF 4.5 2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-09-01 DOI: 10.1007/s11465-023-0752-4

Lianguo Wang, Wei Cai, Yan He, Tao Peng, Jun Xie, Luoke Hu, Li Li

引用次数: 1

Comprehensive kinetostatic modeling and morphology characterization of cable-driven continuum robots for in-situ aero-engine maintenance 用于航空发动机原位维修的索驱动连续机器人的综合动静力学建模和形态表征

2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-09-01 DOI: 10.1007/s11465-023-0756-0

Zheshuai Yang, Laihao Yang, Yu Sun, Xuefeng Chen

{"title":"Comprehensive kinetostatic modeling and morphology characterization of cable-driven continuum robots for in-situ aero-engine maintenance","authors":"Zheshuai Yang, Laihao Yang, Yu Sun, Xuefeng Chen","doi":"10.1007/s11465-023-0756-0","DOIUrl":"https://doi.org/10.1007/s11465-023-0756-0","url":null,"abstract":"Abstract In-situ maintenance is of great significance for improving the efficiency and ensuring the safety of aeroengines. The cable-driven continuum robot (CDCR) with twin-pivot compliant mechanisms, which is enabled with flexible deformation capability and confined space accessibility, has emerged as a novel tool that aims to promote the development of intelligence and efficiency for in-situ aero-engine maintenance. The high-fidelity model that describes the kinematic and morphology of CDCR lays the foundation for the accurate operation and control for in-situ maintenance. However, this model was not well addressed in previous literature. In this study, a general kinetostatic modeling and morphology characterization methodology that comprehensively contains the effects of cable-hole friction, gravity, and payloads is proposed for the CDCR with twin-pivot compliant mechanisms. First, a novel cable-hole friction model with the variable friction coefficient and adaptive friction direction criterion is proposed through structure optimization and kinematic parameter analysis. Second, the cable-hole friction, all-component gravities, deflection-induced center-of-gravity shift of compliant joints, and payloads are all considered to deduce a comprehensive kinetostatic model enabled with the capacity of accurate morphology characterization for CDCR. Finally, a compact continuum robot system is integrated to experimentally validate the proposed kinetostatic model and the concept of in-situ aero-engine maintenance. Results indicate that the proposed model precisely predicts the morphology of CDCR and outperforms conventional models. The compact continuum robot system could be considered a novel solution to perform in-situ maintenance tasks of aero-engines in an invasive manner.","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135638373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Obstacle-circumventing adaptive control of a four-wheeled mobile robot subjected to motion uncertainties 运动不确定性下四轮移动机器人的避障自适应控制

2区工程技术

Frontiers of Mechanical Engineering Pub Date : 2023-09-01 DOI: 10.1007/s11465-023-0753-3

Yiming Yan, Shuting Wang, Yuanlong Xie, Hao Wu, Shiqi Zheng, Hu Li

引用次数: 0