简介：ItisquitecommonthatCollegestudents’writingsareoftenloadedofordinarywordsandmonotonoussentencepatternsbecausetheyoftendeliberatelyavoidsomelanguagestructuresandconjunctions.ThiskindofsketchyandhollowwritingsmayhindertheimprovementofEnglishwritingskill.Thispaperfirstresearchesthisavoidancephenomenonfromthreeaspects:lexis,syntax,anddiscourse,thenexploresthereasonsbehindit,andfinallyputsforthsomeinstructivesuggestionsforimprovingthiscondition.

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简介：Thispaperconsiderstheproblemsofformationandobstacleavoidanceformultiagentsystems.Theobjectiveistodesignatermofagentsthatcanreachadesiredformationwhileavoidingcollisionwithobstacles.Toreducetheamountofinformationinteractionbetweenagentsandtarget,weadopttheleader-followerformationstrategy.Byusingtherecedinghorizoncontrol(RHC),anoptimalproblemisformulatedintermsofcostminimizationunderconstraints.Informationonobstaclesisincorporatedonlineasse...

简介：把数学模型，基于双综合者新有点潜在的功能被指电场的概念在这篇论文介绍；然后，一个新形成控制方法被建议，在哪个潜在的函数在代理人代理人之间并且在代理人障碍之间被使用，当州的反馈控制被申请时代理人和它的目标。这策略使整个潜在的地更简单并且帮助避免一些本地最小。潜在的函数和州的反馈控制的这联合的稳定性被证明。一些模拟被介绍显示出这个控制方法的合理性。

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简介：土壤无脊椎动物和重金属集中不同类地在在南部的俄国包围一家铁采矿企业的大草原阴谋的土壤被散布。这研究估计高土壤无脊椎动物丰富的补丁是否与污染物质的低集中的补丁与一致。为这个目的，由距离索引(SADIE)的空间分析被使用。在Belogorye自然保护区的三条山谷被选择。一条山谷面对了跟踪池溏到北方和另外的二面对的东南或西南。二个采样阴谋在每条山谷被选择，除了对方的60m。在每个阴谋上，16个土壤核心从有在各个之间的5-m距离的4个单位取样联合起来的4×的一个格子被收集。每个土壤核心有76厘米2的一个区域并且是1215厘米深的。所有宏无脊椎动物是hand-sorted并且识别了到家庭。许多土壤无脊椎动物没被金属集中的补丁在土壤控制。象住在崽层的昆虫和另外的无脊椎动物一样，Epigaeic组，直接没与土壤的本地参数被联系。相反，地下的无脊椎的丰富(鼓舞根除幼虫和蚯蚓)有某重金属的显示出的重要分离(Fe，Pb，Zn)在土壤的集中。土壤污染的补缀可以充当地下的土壤无脊椎动物分发的一个领先的因素。在工业上转变的土壤的动物人口的空间结构需要进一步的研究。

简介：因为他们的广泛的应用，无人的表面车辆(USV)成为了研究的一个焦点。保证安全和可靠性并且独立地执行复杂任务，USV被要求拥有环境和有效碰撞回避能力的精确感觉。完成这些，进实时海洋的雷达目标察觉的调查和自治碰撞回避技术被要求，瞄准解决噪音堵塞，在海洋的雷达中的不平的亮度，目标损失，和盲目区域的问题想象。这些技术应该也满足要求即时并且与USV的高航行速度有关的可靠性。因此，这研究基于海洋的雷达开发了一个嵌入的碰撞回避系统，调查了包含适应变光滑的算法和柔韧的分割算法的一个高度即时的目标察觉方法，开发了一个马厩和可靠动态本地环境模型保证USV的安全航行，并且基于调整USV标题和速度在的速度障碍(V障碍)构造了一个碰撞回避算法即时。在多障碍回避的海试用结果第一表明建议回避系统的有效性和效率，然后当时，验证它的大适应性和相对稳定性航行在真实、复杂的海洋的环境的USV。获得的结果将改进USV的聪明的水平并且保证USV独立人士航行的安全。

简介：Focusingonobstacleavoidanceinthree-dimensionalspaceforunmannedaerialvehicle(UAV),thedirectobstacleavoidancemethodindynamicspacebasedonthree-dimensionalvelocityobstaclesphericalcapisproposed,whichquantifiestheinfluenceofthreateningobstaclesthroughvelocityobstaclesphericalcapparameters.Inaddition,theobstacleavoidanceschemesofanypointonthecriticalcurveduringthemulti-obstaclesavoidancearegiven.Throughprediction,theinsertionpointfortheobstacleavoidancecanbeobtainedandtheflightpathcanbereplanned.TakingthePythagoreanHodograph(PH)curvetrajectoryre-planningasanexample,thethree-dimensionaldirectobstacleavoidancemethodindynamicspaceistested.Simulationresultsshowthattheproposedmethodcanrealizetheonlineobstacleavoidancetrajectoryre-planning,whichincreasestheflexibilityofobstacleavoidancegreatly.

简介：认知收音机(CR)技术被相信改进光谱效率。然而，干扰问题由于主要系统和CR系统的共存成为了一个关键问题。在这份报纸，在CR的干扰基于细胞的网络被讨论。干扰情形被分析，考虑到不同干扰采购原料。同时，一个改进模型说出认知干扰戒指被介绍描述每个第二等的用户(苏)的干扰范围。取决于上述分析，图着色基于动态力量分配(GCDPA)计划为干扰被建议回避。模拟结果证明那在CR基于细胞的网络，到主要用户(脓)的干扰能有效地与建议GCDPA计划，和系统产量和力量效率被减轻两个都被改进。

简介：InthispaperwestudythesolutionofSATproblemsformulatedasdiscretedecisionanddiscreteconstrainedoptimizationproblems.Constrainedformulationsarebetterthantraditionalunconstrainedformulationsbecauseviolatedconstraintsmayprovideadditionalforcestoleadasearchtowardsasatisfiableassignment.Wesummarizethetheoryofextendedsaddlepointsinpenaltyformulationsforsolvingdiscreteconstrainedoptimizationproblemsandtheassociateddiscretepenaltymethod(DPM).Wethenexaminevariousformulationsoftheobjectivefunction,choicesofneighborhoodinDPM,strategiesforupdatingpenalties,andheuristicsforavoidingtraps.ExperimentalevaluationsonhardbenchmarkinstancespinpointthattrapscontributesignificantlytotheinefficiencyofDPMandforceatrajectorytorepeatedlyvisitthesamesetofornearbypointsintheoriginalvariablespace.Toaddressthisissue,weproposeandstudytwotrap-avoidancestrategies.Thefirststrategyaddsextrapenaltiesonunsatisfiedclausesinsideatrap,leadingtoverylargepenaltiesforunsatisfiedclausesthataretrappedmoreoftenandmakingtheseclausesmorelikelytobesatisfiedinthefuture.Thesecondstrategystoresinformationonpointsvisitedbefore,whetherinsidetrapsornot,andavoidsvisitingpointsthatareclosetopointsvisitedbefore.Itcanbeimplementedbymodifyingthepenaltyfunctioninsuchawaythat,ifatrajectorygetsclosetopointsvisitedbefore,anextrapenaltywilltakeeffectandforcethetrajectorytoanewregion.Itspecializestothefirststrategybecausetrapsarespecialcasesofpointsvisitedbefore.Finally,weshowexperimentalresultsonevaluatingbenchmarksintheDIMACSandSATLIBarchivesandcompareourresultswithexistingresultsonGSAT,WalkSAT,LSDL,andGrasp.TheresultsdemonstratethatDPMwithtrapavoidanceisrobustaswellaseffectiveforsolvinghardSATproblems.

简介：Animportantconceptproposedintheearlystageofrobotpathplanningfieldistheshrinkingofarobottoapointandmeanwhiletheexpandingofobstaclesintheworkspaceasasetofnewobstacles.TheresultinggrownobstaclesarecalledtheConfigurationSpace(Cspace)obstacles.Thefind-pathproblemisthentransformedintothatoffindingacollision-freepathforapointrobotamongtheCspaceobstacles.However,theresearchexperienceshaveshownthattheCspacetransformationisveryhardwhenthefollowingsituationsoccur:1)boththerobotandobstaclesarenotpolygons,and2)therobotisallowedtorotate.Thissituationgetsevenworsewhentherobotandobstaclesarethreedimensional(3D)objectswithvariousshapes.Forthisreason,directpathplanningapproacheswithouttheCspacetransformationisquiteusefulandexpected.Motivatedbythepracticalrequirementsofrobotpathplanning,ageneralizedconstrainedoptimizationproblem(GCOP)withnotonlylogicANDbutalsologicORrelationshipswasproposedandamathematicalsolutiondevelopedpreviously.Thispaperinheritsthefundamentalideasofinequalityandoptimizationtechniquesfromthepreviouswork,convertstheobstacleavoidanceproblemintoasemi-infiniteconstrainedoptimizationproblemwiththehelpofthemathematicaltransformation,andproposesadirectpathplanningapproachwithoutCspacecalculation,whichisquitedifferentfromtraditionalmethods.Toshowitsmerits,simulationresultsin3Dspacehavebeenpresented.

简介：一个二车轮的活动机器人的一个障碍回避计划被选择适当Lyapunov功能显示出。当考虑障碍时，Lyapunov功能可以有一些本地最小。擦掉本地最小的一个方法被使用用飞机表面盖住最小的功能建议。建议方法的有效性被数字模拟验证。

简介：Andynamicsystemforreal-timeobstacleavoidancepathplanningofredundantrobotsisconstructedinthispaper.Firstly,theinter-framedifferencemethodisusedtoidentifythemovingtargetandtocalculatethetargetarea,thenonthebasisofcolorfeaturesandgradientfeaturesextractedfromthetargetarea,thefeaturefusionCam-Shiftmeanshiftalgorithmisusedtotracktarget,improvingtherobustnessofthetrackingalgorithm.Secondly,aparalleltwo-channeltargetidentificationandlocationmethodbasedonbinocularvisionisproposed,updatingthetarget’sthree-dimensionalinformationinrealtime.Then,adynamiccollision-freepathplanningmethodisimplemented:thesafetyrodsareremovedthroughtheintersectiontest,andtheminimumdistanceisderiveddirectlybyusingthecoordinatevaluesofthetargetinthelocalcoordinatesystemoftherod.Onthisbasis,theobstacleavoidancegainandescapevelocityrelatedtotheminimumdistanceisestablished,andobstacleavoidancepathplanningisimplementedbyusingthezerospacemappingmatrixofredundantrobot.Experimentsareperformedtostudytheefficiencyoftheproposedsystem.

简介：Thisarticlepresentsagoodrobustandreal-timesystemschemeofthemobilerobotobstacledetectionandnavigation,whichprincipleofworkisbasedonthefeaturedescriptorSURF.Inthisscheme,firstly,theimageinformationofthemobilerobotpathwascapturedbythebinocularcamera;thenthefeaturepointswereextractedandcorrespondingmatchedusingSURFtothebinocularimagesastheundetectedobstacles;finallyfixedthepositionoftheobjectivebytheparallaxbetweenthematchingpointscombiningwiththebinocularvisioncalibrationmodel.Theoreticalderivationandexperimentalresultsshowthatthisschemeismoreaccurateforthedetectionandnavigationoftheinterestpoints.Ithasfastmatchingspeedandhighaccuracyandlowerror.So,ithascertainpracticaleffectandpopularizingvalueforthemobilerobotreal-timeobstacleavoidanceandnavigation.

简介：Purpose:Tosummarizetheapproach-avoidanceachievementgoalandperformanceinthesportpsychologyliterature.Methods:Atotalof17publishedstudies,twoofwhichprovidedtwosamples,werelocated.Acceptedmeta-analyticprocedureswereusedwithHedgesgastheeffectsizemetric.Fromthe17studies,73effectsizeswerecalculated.Results:Resultsbasedonarandomeffectsmodelindicatedthattheperformancegoalcontrasthadthelargestfacilitativeimpactonperformancefollowedbythemasteryandperformanceapproachgoals.Bothoftheavoidancegoalsperformanceandmasteryhadsmallnon-significantanddetrimentaleffectsonperformance.Thehomogeneitystatisticsrevealedsignificantheterogeneityfortheapproachandavoidanceperformancegoals.Categoricalmoderatorvariableswereexaminedforstudysexcomposition(male,female,ormixed),meanageofsample(<18yearsor18years),studysetting(labornaturalistic),andnatureofperformancevariable(objectiveorsubjective).Conclusion:Theperformancegoalcontrastholdsvalueforsportperformanceresearch.Contrarytoapproach-avoidancepredictions,themastery-approachgoalandperformanceeffectsizewassignificantandofequalmagnitudeastheperformanceapproachgoalandperformanceeffectsize.Thus,futureresearchshouldcloselytesttheefficacyofboththemastery-andperformancecontrastsinimpactingperformanceofsporttasks.Last,thesignificanteffectsizesreportedinthisreviewareinstarkcontrasttocontemporarymeta-analyticfindingsineducation.Differencesintheapproach-avoidancegoalsinsportandeducationrelativetoperformanceshouldberesearchedfurther.

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简介：StudyontheavoidanceresponseofPenaeuschinensistoheavymetals(Pb,Cr,Zn)andheavymetalmixtures(Pb-Cr,Pb-Zn)iscarredoutusingaY-modelavoidanceapparatus.Theconcentrationscalculatedtoinduce50%avoidanceratebyPenaeuschinensisare11.4,33.2and238.1mg/LforPb,CrandZn,respectively.MixturesofPb-CrandPb-ZnproduceadditiveeffectintheavoidancetestusingPenaeuschinesis.ButwhenthemixedPb-Znsolutionhas0.5toxicunitPband0.5toxicunitZn,themixtureseemstohavesynergisticeffect.

简介：Purpose:ThepurposeofthisquantitativereviewwastosummarizethestateofElliot’sHierarchicalModelofApproachandAvoidanceMotivation,specificallytheantecedentsofthe2×2achievementgoalsinthesport,physicalactivity,andphysicaleducationliterature.Inaddition,theintercorrelationsamongstthe2×2goalswerealsoexamined.Methods:Asystematicreviewoftheliteraturewasconducted.Meta-analyticprocedureswereusedwiththemeanweightedsamplecorrelation(rw)astheeffectsizemetric.TheantecedentswerecodedbyElliot’s(1999)antecedentcategories.Anumberofmoderatorswerecodedapriori.Results:Basedonafixedeffectsmodelfrom47publishedstudies(totaluniquen=15,413)thatmetinclusioncriteria,the2×2achievementgoalsweresignificantlycorrelatedamongsteachotherrangingfromsmalltomediumtolargeinmeaningfulness.Concerningtheantecedents,overalltheyweretheoreticallycorrectinassociations,butonlyafewoftherelationshipsweremediuminmeaningfulness.Mostrelationshipsweresmallinmeaningfulness.Heterogeneitywaspresentfortheinterrcorrelationandantecedentanalyses.Conclusion:FutureresearchisencouragedtogrowandenrichtheunderstandingofachievementgoalswithinElliot’scompleteHierarchicalModelofApproachandAvoidanceMotivationtoincludebothantecedentsandoutcomessimultaneouslytoimproveupontheunderstandingofachievementmotivationinsport,exercise,andphysicalactivitysettings.