Purpose:Head injury criterion(HIC)companied by a rotation-based metric was widely believed to behelpful for head injury prediction in road traffic accidents.Recently,the Euro-New Car AssessmentProgram utilized a newly...Purpose:Head injury criterion(HIC)companied by a rotation-based metric was widely believed to behelpful for head injury prediction in road traffic accidents.Recently,the Euro-New Car AssessmentProgram utilized a newly developed metric called diffuse axonal multi-axis general evaluation(DAMAGE)to explain test device for human occupant restraint(THOR)head injury,which demonstratedexcellent ability in capturing concussions and diffuse axonal injuries.However,there is still a lack ofcomprehensive understanding regarding the effectiveness of using DAMAGE for Hybrid III 50thpercentile male dummy(H50th)head injury assessment.The objective of this study is to determinewhether the DAMAGE could capture the risk of H50th brain injury during small overlap barrier tests.Methods:To achieve this objective,a total of 24 vehicle crash loading curves were collected as input datafor the multi-body simulation.Two commercially available mathematical dynamic models,namelyH50th and THOR,were utilized to investigate the differences in head injury response.Subsequently,adecision method known as simple additive weighting was employed to establish a comprehensive braininjury metric by incorporating the weighted HIC and either DAMAGE or brain injury criterion.Furthermore,35 sets of vehicle crash test data were used to analyze these brain injury metrics.Results:The rotational displacement of the THOR head is significantly greater than that of the H50thhead.The maximum linear and rotational head accelerations experienced by H50th and THOR modelswere(544.6±341.7)m/s^(2),(2468.2±1309.4)rad/s^(2) and(715.2±332.8)m/s^(2),(3778.7±1660.6)rad/s^(2),respectively.Under the same loading condition during small overlap barrier(SOB)tests,THOR exhibits ahigher risk of head injury compared to the H50th model.It was observed that the overall head injuryresponse during the small overlap left test condition is greater than that during the small overlap righttest.Additionally,an equation was formulated to establish the necessary relationship between theDAMAGE values of THOR and H50th.Conclusion:If H50th rather than THOR is employed as an evaluation tool in SOB crash tests,newlydesigned vehicles are more likely to achieve superior performance scores.According to the current injurycurve for DAMAGE and brain injury criterion,it is highly recommended that HIC along with DAMAGE wasprioritized for brain injury assessment in SOB tests.展开更多
In the era of AI,especially large models,the importance of open source has become increasingly prominent.First,open source allows innovation to avoid starting from scratch.Through iterative innovation,it promotes tech...In the era of AI,especially large models,the importance of open source has become increasingly prominent.First,open source allows innovation to avoid starting from scratch.Through iterative innovation,it promotes technical exchanges and learning globally.Second,resources required for large model R&D are difficult for a single institution to obtain.The evaluation of general large models also requires the participation of experts from various industries.Third,without open source collaboration,it is difficult to form a unified upper-layer software ecosystem.Therefore,open source has become an important cooperation mechanism to promote the development of AI and large models.There are two cases to illustrate how open source and international standards interact with each other.展开更多
Driven by the huge demand to explore oceans, underwater wireless communications have been rapidly developed in the past few decades. Due to the complex physical characteristics of water, acoustic wave is the only medi...Driven by the huge demand to explore oceans, underwater wireless communications have been rapidly developed in the past few decades. Due to the complex physical characteristics of water, acoustic wave is the only media available for underwater wireless communication at any distance. As a result, underwater acoustic communication(UAC) is the major research field in underwater wireless communication. In this paper, characteristics of underwater acoustic channels are first introduced and compared with terrestrial communication to demonstrate the difficulties in UAC research. To give a general impression of the UAC, current important research areas are mentioned. Furthermore, different principal modulation-based schemes for short-and medium-range communications with high data rates are investigated and summarized. To evaluate the performance of UAC systems in general,three criteria are presented based on the research publications and our years of experience in high-rate short-to medium-range communications. These three criteria provide useful tools to generally guide the design and evaluate the performance of underwater acoustic communication systems.展开更多
基金This work has been supported by the National Natural ScienceFoundation of China(Grant No.32171305)Natural Science Foundation of Chongqing,China(Grant No.cstc2021jcyj-msxmX0109)Chongqing Technology Innovation and Application Development Project(Grant No.CSTB2023YSZX-JSX0003).
文摘Purpose:Head injury criterion(HIC)companied by a rotation-based metric was widely believed to behelpful for head injury prediction in road traffic accidents.Recently,the Euro-New Car AssessmentProgram utilized a newly developed metric called diffuse axonal multi-axis general evaluation(DAMAGE)to explain test device for human occupant restraint(THOR)head injury,which demonstratedexcellent ability in capturing concussions and diffuse axonal injuries.However,there is still a lack ofcomprehensive understanding regarding the effectiveness of using DAMAGE for Hybrid III 50thpercentile male dummy(H50th)head injury assessment.The objective of this study is to determinewhether the DAMAGE could capture the risk of H50th brain injury during small overlap barrier tests.Methods:To achieve this objective,a total of 24 vehicle crash loading curves were collected as input datafor the multi-body simulation.Two commercially available mathematical dynamic models,namelyH50th and THOR,were utilized to investigate the differences in head injury response.Subsequently,adecision method known as simple additive weighting was employed to establish a comprehensive braininjury metric by incorporating the weighted HIC and either DAMAGE or brain injury criterion.Furthermore,35 sets of vehicle crash test data were used to analyze these brain injury metrics.Results:The rotational displacement of the THOR head is significantly greater than that of the H50thhead.The maximum linear and rotational head accelerations experienced by H50th and THOR modelswere(544.6±341.7)m/s^(2),(2468.2±1309.4)rad/s^(2) and(715.2±332.8)m/s^(2),(3778.7±1660.6)rad/s^(2),respectively.Under the same loading condition during small overlap barrier(SOB)tests,THOR exhibits ahigher risk of head injury compared to the H50th model.It was observed that the overall head injuryresponse during the small overlap left test condition is greater than that during the small overlap righttest.Additionally,an equation was formulated to establish the necessary relationship between theDAMAGE values of THOR and H50th.Conclusion:If H50th rather than THOR is employed as an evaluation tool in SOB crash tests,newlydesigned vehicles are more likely to achieve superior performance scores.According to the current injurycurve for DAMAGE and brain injury criterion,it is highly recommended that HIC along with DAMAGE wasprioritized for brain injury assessment in SOB tests.
文摘In the era of AI,especially large models,the importance of open source has become increasingly prominent.First,open source allows innovation to avoid starting from scratch.Through iterative innovation,it promotes technical exchanges and learning globally.Second,resources required for large model R&D are difficult for a single institution to obtain.The evaluation of general large models also requires the participation of experts from various industries.Third,without open source collaboration,it is difficult to form a unified upper-layer software ecosystem.Therefore,open source has become an important cooperation mechanism to promote the development of AI and large models.There are two cases to illustrate how open source and international standards interact with each other.
基金Project supported by the National Key R&D Program of China(No.2016YFC1400200)the National Natural Science Foundation of China(Nos.61771396 and 61471298)
文摘Driven by the huge demand to explore oceans, underwater wireless communications have been rapidly developed in the past few decades. Due to the complex physical characteristics of water, acoustic wave is the only media available for underwater wireless communication at any distance. As a result, underwater acoustic communication(UAC) is the major research field in underwater wireless communication. In this paper, characteristics of underwater acoustic channels are first introduced and compared with terrestrial communication to demonstrate the difficulties in UAC research. To give a general impression of the UAC, current important research areas are mentioned. Furthermore, different principal modulation-based schemes for short-and medium-range communications with high data rates are investigated and summarized. To evaluate the performance of UAC systems in general,three criteria are presented based on the research publications and our years of experience in high-rate short-to medium-range communications. These three criteria provide useful tools to generally guide the design and evaluate the performance of underwater acoustic communication systems.
