The World Wide Web has become the primary means for information dissemination. Due to the limited resources of the network bandwidth, users always suffer from long time waiting. Web prefetching and web caching are the...The World Wide Web has become the primary means for information dissemination. Due to the limited resources of the network bandwidth, users always suffer from long time waiting. Web prefetching and web caching are the primary approaches to reducing the user perceived access latency and improving the quality of services. In this paper, a Stochastic Petri Nets （SPN） based integrated web prefetching and caching model （IWPCM） is presented and the performance evaluation of IWPCM is made. The performance metrics, access latency, throughput, HR （hit ratio） and BHR （byte hit ratio） are analyzed and discussed. Simulations show that compared with caching only model （CM）, IWPCM can further improve the throughput, HR and BHR efficiently and reduce the access latency. The performance evaluation based on the SPN model can provide a basis for implementation of web prefetching and caching and the combination of web prefetching and caching holds the promise of improving the QoS of web systems.展开更多
During sepsis,neutrophil activation induces endothelial cell(EC)dysfunction partly through neutrophil extracellular trap(NET)release.The triggering receptor expressed on myeloid cell-1(TREM-1)is an orphan immune recep...During sepsis,neutrophil activation induces endothelial cell(EC)dysfunction partly through neutrophil extracellular trap(NET)release.The triggering receptor expressed on myeloid cell-1(TREM-1)is an orphan immune receptor that amplifies the inflammatory response mediated by Toll-like receptor-4(TLR4)engagement.Although the key role of TLR4 signaling in NETosis is known,the role of TREM-1 in this process has not yet been investigated.Here,we report that TREM-1 potentiates NET release by human and murine neutrophils and is a component of the NET structure.In contrast,pharmacologic inhibition or genetic ablation of TREM-1 decreased NETosis in vitro and during experimental septic shock in vivo.Moreover,isolated NETs were able to activate ECs and impair vascular reactivity,and these deleterious effects were dampened by TREM-1 inhibition.TREM-1 may,therefore,constitute a new therapeutic target to prevent NETosis and associated endothelial dysfunction.展开更多
过程挖掘技术将观察到的行为(即事件日志)与建模的行为(如bpmn模型或petri网)联系起来.可以通过对日志进行挖掘,获得实际业务流程模型,再对其中关联严格结构检测,通过并行优化的方法优化实际业务流程模型.目前的业务流程优化主要是针对...过程挖掘技术将观察到的行为(即事件日志)与建模的行为(如bpmn模型或petri网)联系起来.可以通过对日志进行挖掘,获得实际业务流程模型,再对其中关联严格结构检测,通过并行优化的方法优化实际业务流程模型.目前的业务流程优化主要是针对管理者或开发者给出的业务流程模型,其与实际运行中的业务流程可能与之有些许偏差,从而影响了优化结果.在此提出一种新方法对业务流程进行优化.首先使用Prom框架中的Alpha Miner及Heuristic miner获得流程模型的PetriNet及C-net结构;然后使用最大分解的方法修复流程模型;针对修复后的模型提出其中高频简单网部分,并发现关联严格结构,使用Colored Petri nets对关联严格结构重新构造为关联并行结构,确定优化结果.该方法通过实际业务流程的研究案例及比较实验进行评估,其结果表明关联并行优化可明显缩短实际业务流程耗时.展开更多
In response to the production capacity and functionality variations, a genetic algorithm （GA） embedded with deterministic timed Petri nets（DTPN） for reconfigurable production line（RPL） is proposed to solve its s...In response to the production capacity and functionality variations, a genetic algorithm （GA） embedded with deterministic timed Petri nets（DTPN） for reconfigurable production line（RPL） is proposed to solve its scheduling problem. The basic DTPN modules are presented to model the corresponding variable structures in RPL, and then the scheduling model of the whole RPL is constructed. And in the scheduling algorithm, firing sequences of the Petri nets model are used as chromosomes, thus the selection, crossover, and mutation operator do not deal with the elements in the problem space, but the elements of Petri nets model. Accordingly, all the algorithms for GA operations embedded with Petri nets model are proposed. Moreover, the new weighted single-objective optimization based on reconfiguration cost and E/T is used. The results of a DC motor RPL scheduling suggest that the presented DTPN-GA scheduling algorithm has a significant impact on RPL scheduling, and provide obvious improvements over the conventional scheduling method in practice that meets duedate, minimizes reconfiguration cost, and enhances cost effectivity.展开更多
A treelike hybrid multi-cluster tool is composed of both single-arm and dual-arm cluster tools with a treelike topology. Scheduling such a tool is challenging. For a hybrid treelike multi-cluster tool whose bottleneck...A treelike hybrid multi-cluster tool is composed of both single-arm and dual-arm cluster tools with a treelike topology. Scheduling such a tool is challenging. For a hybrid treelike multi-cluster tool whose bottleneck individual tool is process-bound, this work aims at finding its optimal one-wafer cyclic schedule. It is modeled with Petri nets such that a onewafer cyclic schedule is parameterized as its robots' waiting time.Based on the model, this work proves the existence of its onewafer cyclic schedule that features with the ease of industrial implementation. Then, computationally efficient algorithms are proposed to find the minimal cycle time and optimal onewafer cyclic schedule. Multi-cluster tool examples are given to illustrate the proposed approach. The use of the found schedules enables industrial multi-cluster tools to operate with their highest productivity.展开更多
The command and control（C2） is a decision-making process based on human cognition,which contains operational,physical,and human characteristics,so it takes on uncertainty and complexity.As a decision support approac...The command and control（C2） is a decision-making process based on human cognition,which contains operational,physical,and human characteristics,so it takes on uncertainty and complexity.As a decision support approach,Bayesian networks（BNs） provide a framework in which a decision is made by combining the experts＇ knowledge and the specific data.In addition,an expert system represented by human cognitive framework is adopted to express the real-time decision-making process of the decision maker.The combination of the Bayesian decision support and human cognitive framework in the C2 of a specific application field is modeled and executed by colored Petri nets（CPNs）,and the consequences of execution manifest such combination can perfectly present the decision-making process in C2.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 60472044. The authors would like to thank research fellow Dr. Yun Shi of China State Post Bureau and Professor Dr. Jun Zou of Tsinghua University for their helpful and constructive comments.
文摘The World Wide Web has become the primary means for information dissemination. Due to the limited resources of the network bandwidth, users always suffer from long time waiting. Web prefetching and web caching are the primary approaches to reducing the user perceived access latency and improving the quality of services. In this paper, a Stochastic Petri Nets （SPN） based integrated web prefetching and caching model （IWPCM） is presented and the performance evaluation of IWPCM is made. The performance metrics, access latency, throughput, HR （hit ratio） and BHR （byte hit ratio） are analyzed and discussed. Simulations show that compared with caching only model （CM）, IWPCM can further improve the throughput, HR and BHR efficiently and reduce the access latency. The performance evaluation based on the SPN model can provide a basis for implementation of web prefetching and caching and the combination of web prefetching and caching holds the promise of improving the QoS of web systems.
文摘During sepsis,neutrophil activation induces endothelial cell(EC)dysfunction partly through neutrophil extracellular trap(NET)release.The triggering receptor expressed on myeloid cell-1(TREM-1)is an orphan immune receptor that amplifies the inflammatory response mediated by Toll-like receptor-4(TLR4)engagement.Although the key role of TLR4 signaling in NETosis is known,the role of TREM-1 in this process has not yet been investigated.Here,we report that TREM-1 potentiates NET release by human and murine neutrophils and is a component of the NET structure.In contrast,pharmacologic inhibition or genetic ablation of TREM-1 decreased NETosis in vitro and during experimental septic shock in vivo.Moreover,isolated NETs were able to activate ECs and impair vascular reactivity,and these deleterious effects were dampened by TREM-1 inhibition.TREM-1 may,therefore,constitute a new therapeutic target to prevent NETosis and associated endothelial dysfunction.
文摘过程挖掘技术将观察到的行为(即事件日志)与建模的行为(如bpmn模型或petri网)联系起来.可以通过对日志进行挖掘,获得实际业务流程模型,再对其中关联严格结构检测,通过并行优化的方法优化实际业务流程模型.目前的业务流程优化主要是针对管理者或开发者给出的业务流程模型,其与实际运行中的业务流程可能与之有些许偏差,从而影响了优化结果.在此提出一种新方法对业务流程进行优化.首先使用Prom框架中的Alpha Miner及Heuristic miner获得流程模型的PetriNet及C-net结构;然后使用最大分解的方法修复流程模型;针对修复后的模型提出其中高频简单网部分,并发现关联严格结构,使用Colored Petri nets对关联严格结构重新构造为关联并行结构,确定优化结果.该方法通过实际业务流程的研究案例及比较实验进行评估,其结果表明关联并行优化可明显缩短实际业务流程耗时.
基金This project is supported by Key Science-Technology Project of Shanghai City Tenth Five-Year-Plan, China (No.031111002)Specialized Research Fund for the Doctoral Program of Higher Education, China (No.20040247033)Municipal Key Basic Research Program of Shanghai, China (No.05JC14060)
文摘In response to the production capacity and functionality variations, a genetic algorithm （GA） embedded with deterministic timed Petri nets（DTPN） for reconfigurable production line（RPL） is proposed to solve its scheduling problem. The basic DTPN modules are presented to model the corresponding variable structures in RPL, and then the scheduling model of the whole RPL is constructed. And in the scheduling algorithm, firing sequences of the Petri nets model are used as chromosomes, thus the selection, crossover, and mutation operator do not deal with the elements in the problem space, but the elements of Petri nets model. Accordingly, all the algorithms for GA operations embedded with Petri nets model are proposed. Moreover, the new weighted single-objective optimization based on reconfiguration cost and E/T is used. The results of a DC motor RPL scheduling suggest that the presented DTPN-GA scheduling algorithm has a significant impact on RPL scheduling, and provide obvious improvements over the conventional scheduling method in practice that meets duedate, minimizes reconfiguration cost, and enhances cost effectivity.
基金supported in part by Science and Technology Development Fund(FDCT)of Macao(106/2016/A3)the National Natural Science Foundation of China(U1401240)the Delta Electronics Inc and the National Research Foundation(NRF)Singapore under the Corp Lab@University Scheme
文摘A treelike hybrid multi-cluster tool is composed of both single-arm and dual-arm cluster tools with a treelike topology. Scheduling such a tool is challenging. For a hybrid treelike multi-cluster tool whose bottleneck individual tool is process-bound, this work aims at finding its optimal one-wafer cyclic schedule. It is modeled with Petri nets such that a onewafer cyclic schedule is parameterized as its robots' waiting time.Based on the model, this work proves the existence of its onewafer cyclic schedule that features with the ease of industrial implementation. Then, computationally efficient algorithms are proposed to find the minimal cycle time and optimal onewafer cyclic schedule. Multi-cluster tool examples are given to illustrate the proposed approach. The use of the found schedules enables industrial multi-cluster tools to operate with their highest productivity.
基金supported by the National Natural Science Foundation of China (60874068)
文摘The command and control（C2） is a decision-making process based on human cognition,which contains operational,physical,and human characteristics,so it takes on uncertainty and complexity.As a decision support approach,Bayesian networks（BNs） provide a framework in which a decision is made by combining the experts＇ knowledge and the specific data.In addition,an expert system represented by human cognitive framework is adopted to express the real-time decision-making process of the decision maker.The combination of the Bayesian decision support and human cognitive framework in the C2 of a specific application field is modeled and executed by colored Petri nets（CPNs）,and the consequences of execution manifest such combination can perfectly present the decision-making process in C2.
