We study the number of solutions N（B,F） of the diophantine equation n1n2 = n3n4,where 1 ≤ n1≤B, 1≤ n3 ≤B, n2, n4 ∈ F and F C [1, B] is a factor closed set. We study more particularly the case when F = {m = p1^...We study the number of solutions N（B,F） of the diophantine equation n1n2 = n3n4,where 1 ≤ n1≤B, 1≤ n3 ≤B, n2, n4 ∈ F and F C [1, B] is a factor closed set. We study more particularly the case when F = {m = p1^ε1…pk^εk ,εj∈ {0, 1}, 1≤ j ≤ k}, p1,… ,pk being distinct prime numbers.展开更多
Teleoperation is one of the highest-risk activities in manned space activities.An appropriate set of influencing factors is essential for the safety assessment of teleoperation.The examination of the impact of a singl...Teleoperation is one of the highest-risk activities in manned space activities.An appropriate set of influencing factors is essential for the safety assessment of teleoperation.The examination of the impact of a single factor or two factors on space teleoperation as done in the existing works suffers from the lack of a systematic analysis of factors.To address this gap,a hybridα-level set incorporated in the hesitant fuzzy decision making trial and evaluation laboratory(DEMATEL)method was adopted in this study to identify and analyze teleoperation factors.The findings are as follows:(a)A system of influencing factors for teleoperation safety performance was constructed based on an extensive literature review and using the Delphi method with the aid of 30 space experts.The system covered 16 factors grouped based on individual,crew,machine,and context perspectives.(b)Theαlevel affects the screening results of the pivotal influencing factors.For the averageαlevel,five pivotal influencing factors,namely,team communication,basic cognitive ability,display interface information,control mode design,and task complexity,are identified from the 16 influencing factors.The present study represents a valuable effort in extracting the crucial influencing factors that affect teleoperation safety performance.It provides valuable insights from an ergonomic viewpoint and aids in determining priorities for enhancing operational safety.展开更多
文摘We study the number of solutions N（B,F） of the diophantine equation n1n2 = n3n4,where 1 ≤ n1≤B, 1≤ n3 ≤B, n2, n4 ∈ F and F C [1, B] is a factor closed set. We study more particularly the case when F = {m = p1^ε1…pk^εk ,εj∈ {0, 1}, 1≤ j ≤ k}, p1,… ,pk being distinct prime numbers.
基金the National Natural Science Foundation of China(grant number T219293).
文摘Teleoperation is one of the highest-risk activities in manned space activities.An appropriate set of influencing factors is essential for the safety assessment of teleoperation.The examination of the impact of a single factor or two factors on space teleoperation as done in the existing works suffers from the lack of a systematic analysis of factors.To address this gap,a hybridα-level set incorporated in the hesitant fuzzy decision making trial and evaluation laboratory(DEMATEL)method was adopted in this study to identify and analyze teleoperation factors.The findings are as follows:(a)A system of influencing factors for teleoperation safety performance was constructed based on an extensive literature review and using the Delphi method with the aid of 30 space experts.The system covered 16 factors grouped based on individual,crew,machine,and context perspectives.(b)Theαlevel affects the screening results of the pivotal influencing factors.For the averageαlevel,five pivotal influencing factors,namely,team communication,basic cognitive ability,display interface information,control mode design,and task complexity,are identified from the 16 influencing factors.The present study represents a valuable effort in extracting the crucial influencing factors that affect teleoperation safety performance.It provides valuable insights from an ergonomic viewpoint and aids in determining priorities for enhancing operational safety.
