Considering wireless sensor network characteristics,this paper uses network simulator,version2(NS-2)algorithm to improve Ad hoc on-demand distance vector(AODV)routing algorithm,so that it can be applied to wireless se...Considering wireless sensor network characteristics,this paper uses network simulator,version2(NS-2)algorithm to improve Ad hoc on-demand distance vector(AODV)routing algorithm,so that it can be applied to wireless sensor networks.After studying AODV routing protocol,a new algorithm called Must is brought up.This paper introduces the background and algorithm theory of Must,and discusses the details about how to implement Must algorithm.At last,using network simulator(NS-2),the performance of Must is evaluated and compared with that of AODV.Simulation results show that the network using Must algorithm has perfect performance.展开更多
Broadcasting is a basic technique in Mobile ad-hoc network(MANET),and it refers to sending a packet from one node to every other node within the transmission range.Flooding is a type of broadcast where the received pa...Broadcasting is a basic technique in Mobile ad-hoc network(MANET),and it refers to sending a packet from one node to every other node within the transmission range.Flooding is a type of broadcast where the received packet is retransmitted once by every node.The naive flooding technique,floods the network with query messages,while the random walk technique operates by contacting the subsets of every node’s neighbors at each step,thereby restricting the search space.One of the key challenges in an ad-hoc network is the resource or content discovery problem which is about locating the queried resource.Many earlier works have mainly focused on the simulation-based analysis of flooding,and its variants under a wired network.Although,there have been some empirical studies in peer-to-peer(P2P)networks,the analytical results are still lacking,especially in the context of P2P systems running over MANET.In this paper,we describe how P2P resource discovery protocols perform badly over MANETs.To address the limitations,we propose a new protocol named ABRW(Address Broadcast Random Walk),which is a lightweight search approach,designed considering the underlay topology aimed to better suit the unstructured architecture.We provide the mathematical model,measuring the performance of our proposed search scheme with different widely popular benchmarked search techniques.Further,we also derive three relevant search performance metrics,i.e.,mean no.of steps needed to find a resource,the probability of finding a resource,and the mean no.of message overhead.We validated the analytical expressions through simulations.The simulation results closely matched with our analyticalmodel,justifying our findings.Our proposed search algorithm under such highly dynamic self-evolving networks performed better,as it reduced the search latency,decreased the overall message overhead,and still equally had a good success rate.展开更多
Objective To explore the pharmacological mechanism of active saponin compounds of Tuchao Baibiandouren(Lablab Semen Album fried with earth,TCBBDR)in treating type 2 diabetes(T2DM)using UHPLC-Q-Exactive Orbitrap MS and...Objective To explore the pharmacological mechanism of active saponin compounds of Tuchao Baibiandouren(Lablab Semen Album fried with earth,TCBBDR)in treating type 2 diabetes(T2DM)using UHPLC-Q-Exactive Orbitrap MS and network pharmacology.Methods UHPLC-Q-Exactive Orbitrap MS was used for a qualitative analysis of saponin compounds in TCBBDR.PharmMapper and CTD were used to screen drug active compounds and disease targets,and an active compound-target network was constructed via Cytoscape 3.8.0.Molecular docking was applied with the drug active compounds and key targets using AutoDock Vina 1.1.2,and a trajectory for the molecular dynamics simulation was completed by GROMACS 2019-3.Results Sixteen saponin compounds were identified from TCBBDR,along with 292 saponin compoud targets and 792 T2DM targets.Through Venn analysis of target saponin constituents and T2DM related targets,a total of 91 intersection targets were screened out in the treatment of T2DM with saponin.The mean values of degree,betweenness centrality and closeness centrality were taken as the thresholds to screen out 22 key genes,among which 4 key proteins namely MAPK1,IGF1 EGFR,PIK3R1 were selected in the top 10 key genes.On this basis,the saponin active constituent-target-signaling pathway network was established.The Gene Ontology(GO)enrichment analysis showed that the related biological modules included activity of steroid hormone receptor,steroid binding,and insulin receptor binding,etc.;the related signaling pathways were EGFR,PI3K-Akt and MAPK,etc.;regulating signaling pathways like MAPK could induce the proliferation,inhibition and apoptosis of pancreaticβcells,increase the quantity of pancreaticβcells,improve the functions of pancreaticβcells and stimulate the insulin secretion.Docking experiment analysis showed that all selected saponin compounds could enter the active sites of targets and form 3–14 hydrogen bonds with residues of the active sites.Moreover,van der Waals forces were present between chemical compounds and active sites.By combining the docking binding energy,we determined that the chemical compounds showed strong binding energy to the targets.Conclusion TCBBDR exerts therapeutic effects on diabetes through multi-compound and multi-target collaboration.Specifically,saponin components mediate pathways including inflammatory reaction and signal transduction to treat T2DM by regulating several key proteins that interact with EGFR and a series of signaling pathways related to disease development.展开更多
The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This proble...The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This problem has been paid attention and a few of models for passive worm propagation has been presented. Unfortunately, the dynamic properties of this network are ignored in these models. Given the fact, the characteristics of both this network and the passive worm are identified, and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper. Note that the dynamic properties of this network are considered in the presented model. The model has been validated by large scale simulation experiments, which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation.展开更多
This paper analyzes the characteristics of the Peer-to-Peer （P2P） active worm and its attacking mechanism, and then proposes a mathematical model of propagation of the P2P active worm applying Epidemiology. Based on...This paper analyzes the characteristics of the Peer-to-Peer （P2P） active worm and its attacking mechanism, and then proposes a mathematical model of propagation of the P2P active worm applying Epidemiology. Based on the analysis on the protocols of realistic P2P systems, a software which can be used to simulate the P2P network environment and the propagation of P2P active worm is imple- mented in this paper. A large number of simulation experiments are performed using the developed simulation software. The results from these simulation experiments validate the proposed model, which means that the model can be used to analyze the spreading behaviors of the P2P active worm and predict its trend.展开更多
SiB2(simple biosphere model Version 2)是用来模拟生态系统通量较为理想的国外模型,为了探讨其在我国黄河灌区的适用性及利用遥感数据驱动模型的可行性,并用其来研究该地区农田能量收支情况,以位山灌区为研究试点,利用位山实验站1a左...SiB2(simple biosphere model Version 2)是用来模拟生态系统通量较为理想的国外模型,为了探讨其在我国黄河灌区的适用性及利用遥感数据驱动模型的可行性,并用其来研究该地区农田能量收支情况,以位山灌区为研究试点,利用位山实验站1a左右的观测数据对模型进行了验证分析,模拟结果表明:SiB2模型能够较好地模拟位山试验站农田的能量通量、CO2通量及地表温度,净辐射、潜热通量、感热通量、CO2通量与地表温度的模拟值与观测值吻合较好,线性相关系数R分别为0.988,0.714,0.607,0.677与0.933,其中净辐射模拟效果最好,感热通量偏差较大。另外,利用遥感MODIS LAI数据驱动SiB2模型表明,除净辐射外,模拟效果很差,因此在站点尺度遥感LAI(叶面积指数,leaf area index)产品不适合驱动SiB2模型。展开更多
简单介绍MANET(Mobile Ad hoc Network)路由协议后,提出定量评估MANET路由协议性能的六个基本指标。基于网络仿真器NS-2阐述了评估和测试路由协议性能的仿真模型及数据结果的分析方法,并给出仿真实例及其分析。结果表明,模型仿真结果接...简单介绍MANET(Mobile Ad hoc Network)路由协议后,提出定量评估MANET路由协议性能的六个基本指标。基于网络仿真器NS-2阐述了评估和测试路由协议性能的仿真模型及数据结果的分析方法,并给出仿真实例及其分析。结果表明,模型仿真结果接近理论分析和实际情况,该性能评估方法有较强的实用性和通用性。展开更多
文摘Considering wireless sensor network characteristics,this paper uses network simulator,version2(NS-2)algorithm to improve Ad hoc on-demand distance vector(AODV)routing algorithm,so that it can be applied to wireless sensor networks.After studying AODV routing protocol,a new algorithm called Must is brought up.This paper introduces the background and algorithm theory of Must,and discusses the details about how to implement Must algorithm.At last,using network simulator(NS-2),the performance of Must is evaluated and compared with that of AODV.Simulation results show that the network using Must algorithm has perfect performance.
文摘Broadcasting is a basic technique in Mobile ad-hoc network(MANET),and it refers to sending a packet from one node to every other node within the transmission range.Flooding is a type of broadcast where the received packet is retransmitted once by every node.The naive flooding technique,floods the network with query messages,while the random walk technique operates by contacting the subsets of every node’s neighbors at each step,thereby restricting the search space.One of the key challenges in an ad-hoc network is the resource or content discovery problem which is about locating the queried resource.Many earlier works have mainly focused on the simulation-based analysis of flooding,and its variants under a wired network.Although,there have been some empirical studies in peer-to-peer(P2P)networks,the analytical results are still lacking,especially in the context of P2P systems running over MANET.In this paper,we describe how P2P resource discovery protocols perform badly over MANETs.To address the limitations,we propose a new protocol named ABRW(Address Broadcast Random Walk),which is a lightweight search approach,designed considering the underlay topology aimed to better suit the unstructured architecture.We provide the mathematical model,measuring the performance of our proposed search scheme with different widely popular benchmarked search techniques.Further,we also derive three relevant search performance metrics,i.e.,mean no.of steps needed to find a resource,the probability of finding a resource,and the mean no.of message overhead.We validated the analytical expressions through simulations.The simulation results closely matched with our analyticalmodel,justifying our findings.Our proposed search algorithm under such highly dynamic self-evolving networks performed better,as it reduced the search latency,decreased the overall message overhead,and still equally had a good success rate.
基金We thank for the funding support from the Program of Survey of Chinese Medicines of China(No.[2017]66).
文摘Objective To explore the pharmacological mechanism of active saponin compounds of Tuchao Baibiandouren(Lablab Semen Album fried with earth,TCBBDR)in treating type 2 diabetes(T2DM)using UHPLC-Q-Exactive Orbitrap MS and network pharmacology.Methods UHPLC-Q-Exactive Orbitrap MS was used for a qualitative analysis of saponin compounds in TCBBDR.PharmMapper and CTD were used to screen drug active compounds and disease targets,and an active compound-target network was constructed via Cytoscape 3.8.0.Molecular docking was applied with the drug active compounds and key targets using AutoDock Vina 1.1.2,and a trajectory for the molecular dynamics simulation was completed by GROMACS 2019-3.Results Sixteen saponin compounds were identified from TCBBDR,along with 292 saponin compoud targets and 792 T2DM targets.Through Venn analysis of target saponin constituents and T2DM related targets,a total of 91 intersection targets were screened out in the treatment of T2DM with saponin.The mean values of degree,betweenness centrality and closeness centrality were taken as the thresholds to screen out 22 key genes,among which 4 key proteins namely MAPK1,IGF1 EGFR,PIK3R1 were selected in the top 10 key genes.On this basis,the saponin active constituent-target-signaling pathway network was established.The Gene Ontology(GO)enrichment analysis showed that the related biological modules included activity of steroid hormone receptor,steroid binding,and insulin receptor binding,etc.;the related signaling pathways were EGFR,PI3K-Akt and MAPK,etc.;regulating signaling pathways like MAPK could induce the proliferation,inhibition and apoptosis of pancreaticβcells,increase the quantity of pancreaticβcells,improve the functions of pancreaticβcells and stimulate the insulin secretion.Docking experiment analysis showed that all selected saponin compounds could enter the active sites of targets and form 3–14 hydrogen bonds with residues of the active sites.Moreover,van der Waals forces were present between chemical compounds and active sites.By combining the docking binding energy,we determined that the chemical compounds showed strong binding energy to the targets.Conclusion TCBBDR exerts therapeutic effects on diabetes through multi-compound and multi-target collaboration.Specifically,saponin components mediate pathways including inflammatory reaction and signal transduction to treat T2DM by regulating several key proteins that interact with EGFR and a series of signaling pathways related to disease development.
文摘The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This problem has been paid attention and a few of models for passive worm propagation has been presented. Unfortunately, the dynamic properties of this network are ignored in these models. Given the fact, the characteristics of both this network and the passive worm are identified, and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper. Note that the dynamic properties of this network are considered in the presented model. The model has been validated by large scale simulation experiments, which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation.
文摘This paper analyzes the characteristics of the Peer-to-Peer （P2P） active worm and its attacking mechanism, and then proposes a mathematical model of propagation of the P2P active worm applying Epidemiology. Based on the analysis on the protocols of realistic P2P systems, a software which can be used to simulate the P2P network environment and the propagation of P2P active worm is imple- mented in this paper. A large number of simulation experiments are performed using the developed simulation software. The results from these simulation experiments validate the proposed model, which means that the model can be used to analyze the spreading behaviors of the P2P active worm and predict its trend.
文摘SiB2(simple biosphere model Version 2)是用来模拟生态系统通量较为理想的国外模型,为了探讨其在我国黄河灌区的适用性及利用遥感数据驱动模型的可行性,并用其来研究该地区农田能量收支情况,以位山灌区为研究试点,利用位山实验站1a左右的观测数据对模型进行了验证分析,模拟结果表明:SiB2模型能够较好地模拟位山试验站农田的能量通量、CO2通量及地表温度,净辐射、潜热通量、感热通量、CO2通量与地表温度的模拟值与观测值吻合较好,线性相关系数R分别为0.988,0.714,0.607,0.677与0.933,其中净辐射模拟效果最好,感热通量偏差较大。另外,利用遥感MODIS LAI数据驱动SiB2模型表明,除净辐射外,模拟效果很差,因此在站点尺度遥感LAI(叶面积指数,leaf area index)产品不适合驱动SiB2模型。
文摘简单介绍MANET(Mobile Ad hoc Network)路由协议后,提出定量评估MANET路由协议性能的六个基本指标。基于网络仿真器NS-2阐述了评估和测试路由协议性能的仿真模型及数据结果的分析方法,并给出仿真实例及其分析。结果表明,模型仿真结果接近理论分析和实际情况,该性能评估方法有较强的实用性和通用性。
