简介:VesselMonitoringSystem(VMS)providesanewopportunityforquantifiedfishingresearch.ManyapproacheshavebeenproposedtorecognizefishingactivitieswithVMStrajectoriesbasedonthetypesoffishingvessels.However,oneresearchproblemisstillcallingforsolutions,howtoidentifythefishingvesseltypebasedononlyVMStrajectories.ThisproblemisimportantbecauseitrequiresthefishingvesseltypeasapreliminarytorecognizefishingactivitiesfromVMStrajectories.Thispaperproposesfishingvesseltypeidentificationscheme(FVID)basedonlyonVMStrajectories.FVIDexploitsfeatureengineeringandmachinelearningschemesofXGBoostasitstwokeyblocksandclassifiesfishingvesselsintoninetypes.ThedatasetcontainsallthefishingvesseltrajectoriesintheEastChinaSeainMarch2017,including10031pre-registeredfishingvesselsand1350unregisteredvesselsofunknowntypes.Inordertoverifytypeidentificationaccuracy,wefirstconducta4-foldcross-validationonthetrajectoriesofregisteredfishingvessels.Theclassificationaccuracyis95.42%.WethenapplyFVIDtotheunregisteredfishingvesselstoidentifytheirtypes.Afterclassifyingtheunregisteredfishingvesseltypes,theirfishingactivitiesarefurtherrecognizedbasedupontheirtypes.Atlast,wecalculateandcomparethefishingdensitydistributionintheEastChinaSeabeforeandafterapplyingtheunregisteredfishingvessels,confirmingtheimportanceoftypeidentificationofunregisteredfishingvessels.
简介:基于等级特征与可变信息板(VMS)研究了交叉巢式Logit(CNL)模型及网络交通流分配。综合幂函数与指数函数表示方法给出新的信息效用衰减因子,结合道路等级特征表示VMS对车流的影响系数及CNL模型的分配系数;给出等级结构道路网络的随机用户均衡条件下的交叉巢式Logit路径选择模型及其等价数学规划,并设计网络流分配算法。通过实例网络的计算与分析,得到一些有意义的结论:等级结构越显著的路网总出行时间费用越低且其分散参数(θ)弹性绝对值越大;对具有较强随机性的实际路网,若增加一定的确定性则节省更多网络总出行时间;道路网络中设置了VMS时总出行时间受分散参数的影响更小。
简介:WefallintodisusetheJUHUsystembasedonthePDP/11computerforRSX11Moperationsystem,andupdateourmulti-parameterdataaequisitionandanalysissystem’shardwareandsoftwarebasedonVAXIIcomputerandOpenVMSoperationsystem,makeitadaptedtotherecentphysicsexperiment.Inthispaper,wedescribetheupdatedinulti-parameterdataacquisitionandanalysissystem’shardware,softwareconfigurationandsystemfunction.