目的采用Meta分析评价限制性输血与开放性输血策略对急性心肌梗死患者预后的影响。方法计算机检索PubMed、Embase、Web of Science、中国生物医学文献服务系统(SinoMed)、维普(VIP)、中国知网(CNKI)及万方数据知识服务平台(wanfang Data...目的采用Meta分析评价限制性输血与开放性输血策略对急性心肌梗死患者预后的影响。方法计算机检索PubMed、Embase、Web of Science、中国生物医学文献服务系统(SinoMed)、维普(VIP)、中国知网(CNKI)及万方数据知识服务平台(wanfang Data)中有关急性心肌梗死患者接受输血治疗的随机对照试验(RCT),检索时间均从建库至2022年12月。由2名研究者按照纳入排除标准筛选文献、提取资料,2名评价员独立对纳入文献的质量进行评价,采用RevMan5.3进行Meta分析,比较限制性输血与开放性输血策略对急性心肌梗死患者住院期间全因病亡率,总死亡率,随访再梗塞、非计划血管重建、心力衰竭及卒中发生等心血管不良事件的影响差异。结果最终纳入6项研究共3311例患者。Meta分析结果显示,限制性输血与开放性输血策略在院内死亡风险相对危险度(RR)RR=0.68,95%CI为0.31~1.48,P=0.33、总体死亡率(RR=0.83,95%CI为0.47~1.49,P=0.54)、随访再梗塞(RR=1.59,95%CI为0.38~6.75,P=0.53)、非计划血管重建(RR=0.83,95%CI为0.39~1.73,P=0.61)、心力衰竭(RR=0.74,95%CI为0.16~3.46,P=0.70)、卒中发生(RR=0.69,95%CI为0.14~3.48,P=0.65)等差异均无统计学意义。结论限制性输血与开放性输血比较,老年AMI患者住院期间全因病亡率,总死亡率,随访再梗塞、非计划血管重建、心力衰竭及卒中发生等心血管不良事件的发生率未见明显差异,由于纳入研究异质性较高,需更多RCT进一步证实,临床应谨慎对待本研究的结论。展开更多
目的评价腘动脉-膝关节后囊间隙(infiltration between the popliteal artery and the capsule of the posterior knee,iPACK)阻滞对比关节周围注射(periarticular injection,PAI)在全膝关节置换(total knee arthroplasty,TKA)术后镇痛...目的评价腘动脉-膝关节后囊间隙(infiltration between the popliteal artery and the capsule of the posterior knee,iPACK)阻滞对比关节周围注射(periarticular injection,PAI)在全膝关节置换(total knee arthroplasty,TKA)术后镇痛中的作用。方法检索PubMed、EMBASE、Web of Science、中国生物医学文献数据库(CBM)、中文科技期刊全文数据库(VIP)、中国期刊全文数据库(CNKI)及万方数据库中iPACK对比PAI对TKA术后镇痛的随机对照试验(RCT),时间均从建库至2021年12月。2位研究者按照纳入标准筛选文献、提取资料,2位评价员独立对纳入文献的质量进行评价,采用RevMan5.3进行meta分析。结果纳入6个RCT共440例患者。与PAI相比,iPACK组术后24 h吗啡累积使用量较少(MD=-4.21,95%CI:-7.18~-1.24,P=0.005),术后12 h运动状态和24、48 h静息状态、运动状态下疼痛视觉模拟评分(Visual Analogue Scale,VAS)降低,差异有统计学意义(P<0.05),术后12 h静息状态VAS差异无统计学意义(P>0.05);2组术后第1天、第2天行走距离相当,差异无统计学意义(P>0.05)。结论与PAI相比,iPACK阻滞能更有效地减轻TKA术后疼痛,减少阿片类药物用量,不影响术后活动,用于TKA术后镇痛安全有效。展开更多
The current mathematical models for the storage assignment problem are generally established based on the traveling salesman problem(TSP),which has been widely applied in the conventional automated storage and retriev...The current mathematical models for the storage assignment problem are generally established based on the traveling salesman problem(TSP),which has been widely applied in the conventional automated storage and retrieval system(AS/RS).However,the previous mathematical models in conventional AS/RS do not match multi-tier shuttle warehousing systems(MSWS) because the characteristics of parallel retrieval in multiple tiers and progressive vertical movement destroy the foundation of TSP.In this study,a two-stage open queuing network model in which shuttles and a lift are regarded as servers at different stages is proposed to analyze system performance in the terms of shuttle waiting period(SWP) and lift idle period(LIP) during transaction cycle time.A mean arrival time difference matrix for pairwise stock keeping units(SKUs) is presented to determine the mean waiting time and queue length to optimize the storage assignment problem on the basis of SKU correlation.The decomposition method is applied to analyze the interactions among outbound task time,SWP,and LIP.The ant colony clustering algorithm is designed to determine storage partitions using clustering items.In addition,goods are assigned for storage according to the rearranging permutation and the combination of storage partitions in a 2D plane.This combination is derived based on the analysis results of the queuing network model and on three basic principles.The storage assignment method and its entire optimization algorithm method as applied in a MSWS are verified through a practical engineering project conducted in the tobacco industry.The applying results show that the total SWP and LIP can be reduced effectively to improve the utilization rates of all devices and to increase the throughput of the distribution center.展开更多
Slotting strategy heavily influences the throughput and operational cost of automated order picking system with multiple dispenser types, which is called the complex automated order picking system (CAOPS). Existing re...Slotting strategy heavily influences the throughput and operational cost of automated order picking system with multiple dispenser types, which is called the complex automated order picking system (CAOPS). Existing research either focuses on one aspect of the slotting optimization problem or only considers one part of CAOPS, such as the Low-volume Dispensers, to develop corresponding slotting strategies. In order to provide a comprehensive and systemic approach, a fluid-based slotting strategy is proposed in this paper. The configuration of CAOPS is presented with specific reference to its fast-picking and restocking subsystems. Based on extended fluid model, a nonlinear mathematical programming model is developed to determine the optimal volume allotted to each stock keeping unit (SKU) in a certain mode by minimize the restocking cost of that mode. Conclusion from the allocation model is specified for the storage modules of high-volume dispensers and low-volume dispensers. Optimal allocation of storage resources in the fast-picking area of CAOPS is then discussed with the aim of identifying the optimal space of each picking mode. The SKU assignment problem referring to the total restocking cost of CAOPS is analyzed and a greedy heuristic with low time complexity is developed according to the characteristics of CAOPS. Real life application from the tobacco industry is presented in order to exemplify the proposed slotting strategy and assess the effectiveness of the developed methodology. Entry-item-quantity (EIQ) based experiential solutions and proposed-model-based near-optimal solutions are compared. The comparison results show that the proposed strategy generates a savings of over 18% referring to the total restocking cost over one-year period. The strategy proposed in this paper, which can handle the multiple dispenser types, provides a practical quantitative slotting method for CAOPS and can help picking-system-designers make slotting decisions efficiently and effectively.展开更多
The idle time which is part of the order fulfillment time is decided by the number of items in the zone; therefore the item assignment method affects the picking efficiency. Whereas previous studies only focus on the ...The idle time which is part of the order fulfillment time is decided by the number of items in the zone; therefore the item assignment method affects the picking efficiency. Whereas previous studies only focus on the balance of number of kinds of items between different zones but not the number of items and the idle time in each zone. In this paper, an idle factor is proposed to measure the idle time exactly. The idle factor is proven to obey the same vary trend with the idle time, so the object of this problem can be simplified from minimizing idle time to minimizing idle factor. Based on this, the model of item assignment problem in synchronized zone automated order picking system is built. The model is a form of relaxation of parallel machine scheduling problem which had been proven to be NP-complete. To solve the model, a taboo search algorithm is proposed. The main idea of the algorithm is minimizing the greatest idle factor of zones with the 2-exchange algorithm. Finally, the simulation which applies the data collected from a tobacco distribution center is conducted to evaluate the performance of the algorithm. The result verifies the model and shows the algorithm can do a steady work to reduce idle time and the idle time can be reduced by 45.63% on average. This research proposed an approach to measure the idle time in synchronized zone automated order picking system. The approach can improve the picking efficiency significantly and can be seen as theoretical basis when optimizing the synchronized automated order picking systems.展开更多
文摘目的采用Meta分析评价限制性输血与开放性输血策略对急性心肌梗死患者预后的影响。方法计算机检索PubMed、Embase、Web of Science、中国生物医学文献服务系统(SinoMed)、维普(VIP)、中国知网(CNKI)及万方数据知识服务平台(wanfang Data)中有关急性心肌梗死患者接受输血治疗的随机对照试验(RCT),检索时间均从建库至2022年12月。由2名研究者按照纳入排除标准筛选文献、提取资料,2名评价员独立对纳入文献的质量进行评价,采用RevMan5.3进行Meta分析,比较限制性输血与开放性输血策略对急性心肌梗死患者住院期间全因病亡率,总死亡率,随访再梗塞、非计划血管重建、心力衰竭及卒中发生等心血管不良事件的影响差异。结果最终纳入6项研究共3311例患者。Meta分析结果显示,限制性输血与开放性输血策略在院内死亡风险相对危险度(RR)RR=0.68,95%CI为0.31~1.48,P=0.33、总体死亡率(RR=0.83,95%CI为0.47~1.49,P=0.54)、随访再梗塞(RR=1.59,95%CI为0.38~6.75,P=0.53)、非计划血管重建(RR=0.83,95%CI为0.39~1.73,P=0.61)、心力衰竭(RR=0.74,95%CI为0.16~3.46,P=0.70)、卒中发生(RR=0.69,95%CI为0.14~3.48,P=0.65)等差异均无统计学意义。结论限制性输血与开放性输血比较,老年AMI患者住院期间全因病亡率,总死亡率,随访再梗塞、非计划血管重建、心力衰竭及卒中发生等心血管不良事件的发生率未见明显差异,由于纳入研究异质性较高,需更多RCT进一步证实,临床应谨慎对待本研究的结论。
文摘目的评价腘动脉-膝关节后囊间隙(infiltration between the popliteal artery and the capsule of the posterior knee,iPACK)阻滞对比关节周围注射(periarticular injection,PAI)在全膝关节置换(total knee arthroplasty,TKA)术后镇痛中的作用。方法检索PubMed、EMBASE、Web of Science、中国生物医学文献数据库(CBM)、中文科技期刊全文数据库(VIP)、中国期刊全文数据库(CNKI)及万方数据库中iPACK对比PAI对TKA术后镇痛的随机对照试验(RCT),时间均从建库至2021年12月。2位研究者按照纳入标准筛选文献、提取资料,2位评价员独立对纳入文献的质量进行评价,采用RevMan5.3进行meta分析。结果纳入6个RCT共440例患者。与PAI相比,iPACK组术后24 h吗啡累积使用量较少(MD=-4.21,95%CI:-7.18~-1.24,P=0.005),术后12 h运动状态和24、48 h静息状态、运动状态下疼痛视觉模拟评分(Visual Analogue Scale,VAS)降低,差异有统计学意义(P<0.05),术后12 h静息状态VAS差异无统计学意义(P>0.05);2组术后第1天、第2天行走距离相当,差异无统计学意义(P>0.05)。结论与PAI相比,iPACK阻滞能更有效地减轻TKA术后疼痛,减少阿片类药物用量,不影响术后活动,用于TKA术后镇痛安全有效。
基金Supported by National Natural Science Foundation of China(Grant No.661403234)Shandong Provincial Science and Techhnology Development Plan of China(Grant No.2014GGX106009)
文摘The current mathematical models for the storage assignment problem are generally established based on the traveling salesman problem(TSP),which has been widely applied in the conventional automated storage and retrieval system(AS/RS).However,the previous mathematical models in conventional AS/RS do not match multi-tier shuttle warehousing systems(MSWS) because the characteristics of parallel retrieval in multiple tiers and progressive vertical movement destroy the foundation of TSP.In this study,a two-stage open queuing network model in which shuttles and a lift are regarded as servers at different stages is proposed to analyze system performance in the terms of shuttle waiting period(SWP) and lift idle period(LIP) during transaction cycle time.A mean arrival time difference matrix for pairwise stock keeping units(SKUs) is presented to determine the mean waiting time and queue length to optimize the storage assignment problem on the basis of SKU correlation.The decomposition method is applied to analyze the interactions among outbound task time,SWP,and LIP.The ant colony clustering algorithm is designed to determine storage partitions using clustering items.In addition,goods are assigned for storage according to the rearranging permutation and the combination of storage partitions in a 2D plane.This combination is derived based on the analysis results of the queuing network model and on three basic principles.The storage assignment method and its entire optimization algorithm method as applied in a MSWS are verified through a practical engineering project conducted in the tobacco industry.The applying results show that the total SWP and LIP can be reduced effectively to improve the utilization rates of all devices and to increase the throughput of the distribution center.
基金supported by China Scholarship Council (Grant No.2007102074)National Natural Science Foundation of China (Grant No.50175064)+2 种基金Georgia Institute of Technology Visiting Research EngineerProgram of the United States (Grant No. 2401247)Graduate InnovationFoundation of Shandong University, China (Grant No. yzc09066)Costal International Logistics Company of the United States (Project No.20080727)
文摘Slotting strategy heavily influences the throughput and operational cost of automated order picking system with multiple dispenser types, which is called the complex automated order picking system (CAOPS). Existing research either focuses on one aspect of the slotting optimization problem or only considers one part of CAOPS, such as the Low-volume Dispensers, to develop corresponding slotting strategies. In order to provide a comprehensive and systemic approach, a fluid-based slotting strategy is proposed in this paper. The configuration of CAOPS is presented with specific reference to its fast-picking and restocking subsystems. Based on extended fluid model, a nonlinear mathematical programming model is developed to determine the optimal volume allotted to each stock keeping unit (SKU) in a certain mode by minimize the restocking cost of that mode. Conclusion from the allocation model is specified for the storage modules of high-volume dispensers and low-volume dispensers. Optimal allocation of storage resources in the fast-picking area of CAOPS is then discussed with the aim of identifying the optimal space of each picking mode. The SKU assignment problem referring to the total restocking cost of CAOPS is analyzed and a greedy heuristic with low time complexity is developed according to the characteristics of CAOPS. Real life application from the tobacco industry is presented in order to exemplify the proposed slotting strategy and assess the effectiveness of the developed methodology. Entry-item-quantity (EIQ) based experiential solutions and proposed-model-based near-optimal solutions are compared. The comparison results show that the proposed strategy generates a savings of over 18% referring to the total restocking cost over one-year period. The strategy proposed in this paper, which can handle the multiple dispenser types, provides a practical quantitative slotting method for CAOPS and can help picking-system-designers make slotting decisions efficiently and effectively.
基金Supported by Independent Innovation Foundation of Shandong University of China(Grant No.2013GN007)
文摘The idle time which is part of the order fulfillment time is decided by the number of items in the zone; therefore the item assignment method affects the picking efficiency. Whereas previous studies only focus on the balance of number of kinds of items between different zones but not the number of items and the idle time in each zone. In this paper, an idle factor is proposed to measure the idle time exactly. The idle factor is proven to obey the same vary trend with the idle time, so the object of this problem can be simplified from minimizing idle time to minimizing idle factor. Based on this, the model of item assignment problem in synchronized zone automated order picking system is built. The model is a form of relaxation of parallel machine scheduling problem which had been proven to be NP-complete. To solve the model, a taboo search algorithm is proposed. The main idea of the algorithm is minimizing the greatest idle factor of zones with the 2-exchange algorithm. Finally, the simulation which applies the data collected from a tobacco distribution center is conducted to evaluate the performance of the algorithm. The result verifies the model and shows the algorithm can do a steady work to reduce idle time and the idle time can be reduced by 45.63% on average. This research proposed an approach to measure the idle time in synchronized zone automated order picking system. The approach can improve the picking efficiency significantly and can be seen as theoretical basis when optimizing the synchronized automated order picking systems.
