In this paper,a new algorithm combining the features of bi-direction evolutionary structural optimization(BESO)and reinforcement learning(RL)is proposed for continuum structural topology optimization(STO).In contrast ...In this paper,a new algorithm combining the features of bi-direction evolutionary structural optimization(BESO)and reinforcement learning(RL)is proposed for continuum structural topology optimization(STO).In contrast to conventional approaches which only generate a certain quasi-optimal solution,the goal of the combined method is to provide more quasi-optimal solutions for designers such as the idea of generative design.Two key components were adopted.First,besides sensitivity,value function updated by Monte-Carlo reinforcement learning was utilized to measure the importance of each element,which made the solving process convergent and closer to the optimum.Second,ε-greedy policy added a random perturbation to the main search direction so as to extend the search ability.Finally,the quality and diversity of solutions could be guaranteed by controlling the value of compliance as well as Intersection-over-Union(IoU).Results of several 2D and 3D compliance minimization problems,including a geometrically nonlinear case,show that the combined method is capable of generating a group of good and different solutions that satisfy various possible requirements in engineering design within acceptable computation cost.展开更多
目的比较ICU弹性探视制度与限制性探视制度对患者、家属及医务人员的影响。方法计算机检索PubMed、Cochrane Library、Embase、Web of Science、中国知网、万方医学数据库、维普数据库和中国生物医学文献数据库公开发表的与ICU探视相关...目的比较ICU弹性探视制度与限制性探视制度对患者、家属及医务人员的影响。方法计算机检索PubMed、Cochrane Library、Embase、Web of Science、中国知网、万方医学数据库、维普数据库和中国生物医学文献数据库公开发表的与ICU探视相关的文献。2名研究者提取资料与评价文献质量,采用Stata13.0软件进行Meta分析。结果研究共纳入28篇文献,其中包括随机对照试验研究12项,类实验研究16项,总样本量21816例。Meta结果分析显示,与限制性探视制度相比,弹性探视制度不会增加ICU获得性感染[OR=0.860,95%CI(0.630~1.170),P=0.336],能降低患者谵妄的发生率[OR=0.421,95%CI(0.201~0.883),P=0.022],减轻患者焦虑抑郁程度[SMD=-2.741,95%CI(-4.782~-0.69),P=0.009],能提高家属满意度[OR=4.046,95%CI(2.363~6.927),P<0.001],对患者ICU住院时间、死亡率、医务人员的职业倦怠无明显影响。结论与限制性探视制度相比,弹性探视制度能降低患者谵妄的发生率与抑郁程度,提高家属满意度,对患者ICU获得性感染与医务人员职业倦怠无明显影响。展开更多
文摘In this paper,a new algorithm combining the features of bi-direction evolutionary structural optimization(BESO)and reinforcement learning(RL)is proposed for continuum structural topology optimization(STO).In contrast to conventional approaches which only generate a certain quasi-optimal solution,the goal of the combined method is to provide more quasi-optimal solutions for designers such as the idea of generative design.Two key components were adopted.First,besides sensitivity,value function updated by Monte-Carlo reinforcement learning was utilized to measure the importance of each element,which made the solving process convergent and closer to the optimum.Second,ε-greedy policy added a random perturbation to the main search direction so as to extend the search ability.Finally,the quality and diversity of solutions could be guaranteed by controlling the value of compliance as well as Intersection-over-Union(IoU).Results of several 2D and 3D compliance minimization problems,including a geometrically nonlinear case,show that the combined method is capable of generating a group of good and different solutions that satisfy various possible requirements in engineering design within acceptable computation cost.
文摘目的比较ICU弹性探视制度与限制性探视制度对患者、家属及医务人员的影响。方法计算机检索PubMed、Cochrane Library、Embase、Web of Science、中国知网、万方医学数据库、维普数据库和中国生物医学文献数据库公开发表的与ICU探视相关的文献。2名研究者提取资料与评价文献质量,采用Stata13.0软件进行Meta分析。结果研究共纳入28篇文献,其中包括随机对照试验研究12项,类实验研究16项,总样本量21816例。Meta结果分析显示,与限制性探视制度相比,弹性探视制度不会增加ICU获得性感染[OR=0.860,95%CI(0.630~1.170),P=0.336],能降低患者谵妄的发生率[OR=0.421,95%CI(0.201~0.883),P=0.022],减轻患者焦虑抑郁程度[SMD=-2.741,95%CI(-4.782~-0.69),P=0.009],能提高家属满意度[OR=4.046,95%CI(2.363~6.927),P<0.001],对患者ICU住院时间、死亡率、医务人员的职业倦怠无明显影响。结论与限制性探视制度相比,弹性探视制度能降低患者谵妄的发生率与抑郁程度,提高家属满意度,对患者ICU获得性感染与医务人员职业倦怠无明显影响。
