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具有固定运行时分的列车运行控制系统研究 被引量:7
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作者 刘海东 陈绍宽 +2 位作者 褚琴 王靓 陈善亮 《北方交通大学学报》 CSCD 北大核心 2002年第5期24-27,共4页
探讨了列车运行模拟系统的总体结构 ,针对给定运行时分条件下列车运行的算法 ,构造了在节时、节能、定时条件下列车运行模拟系统 ,结合案例给出了列车运行的模拟结果 ,结果表明定时算法的误差在 30s以内 .
关键词 固定运行时分 列车运行控制系统 牵引计算 定量运行 智能控制 计算机模拟 列车运行模拟系统
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城轨列车运行曲线计算仿真研究 被引量:1
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作者 蒋露晴 王超 +2 位作者 吴晓波 宋美玉 林飞 《电气应用》 2022年第7期57-65,共9页
列车运行曲线是分析列车运动状态、能耗指标等性能的基础,也可作为驾驶员导引系统或列车自动控制系统的输入。首先分析了列车的动力学原理,根据列车受到的牵引力、制动力以及运行阻力建立了列车受力模型。选择最小时分和固定时分两种运... 列车运行曲线是分析列车运动状态、能耗指标等性能的基础,也可作为驾驶员导引系统或列车自动控制系统的输入。首先分析了列车的动力学原理,根据列车受到的牵引力、制动力以及运行阻力建立了列车受力模型。选择最小时分和固定时分两种运行策略进行列车运行曲线计算,分析最小时分和固定时分运行策略包含的工况序列,结合给定线路的条件信息划分限速区间,对相邻工况区间的限速情况进行判断,以此确定各子区间的所含工况情况。最终以北京某地铁线路数据为例,输入至编写好的程序中,得到列车在最小时分和固定时分策略下的运行曲线。 展开更多
关键词 运行曲线 城轨系统 最小时分 固定时分 限速区间
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适用于飞行自组网的闲置时隙预约TDMA协议 被引量:3
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作者 陆毅 符杰林 +2 位作者 仇洪冰 林基明 李燕龙 《计算机工程》 CAS CSCD 北大核心 2021年第3期202-208,共7页
在飞行自组网中,固定时隙分配时分多址接入(TDMA)协议存在闲置时隙无法成功使用的问题。通过对TDMA协议引入闲置时隙预约机制,提出一种支持业务优先级传输机制的闲置时隙预约TDMA协议。采用短帧长的方式满足协同与控制业务的低时延传输... 在飞行自组网中,固定时隙分配时分多址接入(TDMA)协议存在闲置时隙无法成功使用的问题。通过对TDMA协议引入闲置时隙预约机制,提出一种支持业务优先级传输机制的闲置时隙预约TDMA协议。采用短帧长的方式满足协同与控制业务的低时延传输需求,并利用闲置时隙预约机制允许节点使用闲置时隙传输感知业务,从而满足感知业务的高吞吐量传输性能要求。仿真结果表明,与CF-MAC和CTMAC协议相比,该协议能够在降低传输时延的同时,有效提高信道利用率和网络吞吐量。 展开更多
关键词 无人飞行器集群 飞行自组网 固定时隙分配时分多址接入 网络吞吐量 闲置时隙
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Hemihepatic versus total hepatic inflow occlusion during hepatectomy:A systematic review and meta-analysis 被引量:20
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作者 Hai-Qing Wang Jia-Yin Yang Lu-Nan Yan 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第26期3158-3164,共7页
AIM: To evaluate the clinical outcomes of patients undergoing hepatectomy with hemihepatic vascular occlusion (HHO) compared with total hepatic inflow occlusion (THO). METHODS: Randomized controlled trials (RCT... AIM: To evaluate the clinical outcomes of patients undergoing hepatectomy with hemihepatic vascular occlusion (HHO) compared with total hepatic inflow occlusion (THO). METHODS: Randomized controlled trials (RCTs) co- mparing hemihepatic vascular occlusion and total he- patic inflow occlusion were included by a systematic literature search. Two authors independently assessed the trials for inclusion and extracted the data. A meta- analysis was conducted to estimate blood loss, transfu- sion requirement, and liver injury based on the levels of aspartate aminotransferase (AST) and alanine arni- notransferase (ALT). Either the fixed effects model or random effects model was used. RESULTS- Four RCTs including 338 patients met the predefined inclusion criteria. A total of 167 patients were treated with THO and 171 with HHO. Metaanalysis of AST levels on postoperative day 1 indicated higher levels in the THO group with weighted mean dif- ference (WMD) 342.27; 95% confidence intervals (CI) 217.28-467.26; P = 0.00001; I2 = 16%. Meta-analysis showed no significant difference between THO group and HHO group on blood loss, transfusion requirement, mortality, morbidity, operating time, ischemic duration, hospital stay, ALT levels on postoperative day 1, 3 and 7 and AST levels on postoperative day 3 and 7. CONCLUSION: Hemihepatic vascular occlusion does not offer satisfying benefit to the patients undergoing hepatic resection. However, they have less liver injury after liver resections. 展开更多
关键词 Inflow occlusion Hemihepatic Vascular occlusion HEPATECTOMY Pringle maneuver
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The role of trochanteric flip osteotomy in fixation of certain acetabular fractures 被引量:7
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作者 Sandeep Gupta Jagdeep Singh Jagandeep Singh Virk 《Chinese Journal of Traumatology》 CAS CSCD 2017年第3期161-165,共5页
Purpose: Complete visualization of certain acetabular fractures of posterior wall or column with cranial extension involving superior dome from standard surgical exposures is a challenge. Osteotomy of the greater tro... Purpose: Complete visualization of certain acetabular fractures of posterior wall or column with cranial extension involving superior dome from standard surgical exposures is a challenge. Osteotomy of the greater trochanter has been used to enhance fracture visualization, especially the dome, in posterior and lateral exposures of the acetabulum, it also decreases the need for excessive muscle retraction. The purpose of the study was to investigate the outcome associated with trochanteric flip osteotomy in the management of certain acetahulum fractures. Methods: From January 2011 to December 2013, 25 displaced acetabular fractures were treated by open reduction and internal fixation. The fractures were managed using a Kocher-Langenbeck approach along with trochanteric flip osteotomy. At 3rd, 6th and 24th month follow-up, all patients had radiographic examination and underwent a final clinical evaluation based on the modified Merle d'Auhigne and Postei score. The strength of the abductors was assessed according to the Medical Research Council (MRC) grading system. Results: Congruent reduction was achieved in all patients and all osteotomies healed within an average period of 3.8 months. All our patients were allowed full weight bearing at the end of 3 months and with no abductor lurch at the end of 6 months follow-up. There were no cases of avascular necrosis of femoral head. None of the patients had any neurovascular complication or infection by the end of the follow-up period. Conclusion: Truchanteric flip osteotomy is a very effective technique to fix certain acetabular fractures especially those with dome involvement. It is more accurate and associated with no significant com- plications compared with conventional way. 展开更多
关键词 Kocher-Langenbeck approach Acetabular fractures Trochanteric osteotomy Posterior wall Superior dome
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Approximation for counts of head runs
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作者 ZHANG Mei 《Science China Mathematics》 SCIE 2011年第2期311-324,共14页
In this paper, we study the count of head runs up to a fixed time in a two-state stationary Markov chain. We prove that in total variance distance, the negative binomial, Poisson and binomial distributions are appropr... In this paper, we study the count of head runs up to a fixed time in a two-state stationary Markov chain. We prove that in total variance distance, the negative binomial, Poisson and binomial distributions are appropriate approximations according to the relation of the variance and mean of the count, generalizing earlier results in previous literatures. The proof is based on Stein's method and coupling. 展开更多
关键词 head run negative binomial distribution Poisson distribution binomial distribution Stein's method total variation distance coupling
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