一种巡检机器人智能路径规划方法

提出了一种在栅格地图上使用参数可调势场法进行避障的巡检机器人智能路径规划方法.地图采用Hector SLAM算法建立,然后在全局范围内指定目标点并使用变粒度栅格法进行全局路径规划.遇到障碍物时,则在局部小范围内使用参数可调的人工势场法来进行局部路径规划和避障.该方法能有效地提高全局路径规划的效率以及局部避障的准确性,实验验证了该方法的快速性与有效性.     

基于混合人工势场-蚁群算法的机器人避障

针对移动机器人避障的路径规划问题,提出一种基于混合人工势场-蚁群算法的方法。在栅格环境中,以人工势场法的规划信息作为蚁群算法寻优的基础,引入势场合力作为蚂蚁搜索路径点的部分启发信息。Mat-lab7.6仿真表明,该方法解决了人工势场法的目标不可达、易陷入极值点等弊端,提高了经典蚁群算法的寻优效果和收敛速率,具有更强的稳定性和环境适应力。     

基于改进势场蚁群算法的AGV路径规划

针对传统蚁群算法用于路径规划问题时易出现初期搜索盲目性以及易陷入局部最优的问题,本文提出一种改进的势场蚁群算法.首先将人工势场算法融合到蚁群算法中,通过障碍物和目标点产生的势场合力作为部分启发信息,减小路径搜索初期的盲目性,从而加快算法的收敛性;然后对算法中的路径选择策略进行了分析和优化,通过设置临时禁忌表排除部分栅格...     

基于势场蚁群算法的机器人全局路径规划

研究了智能移动机器人的全局路径规划算法改进问题.结合蚁群算法的全局性与人工势场的确定性优势,提出一种势场蚁群算法.即在基本蚁群算法迭代初期,通过人工势场法影响蚂蚁的信息素量,从而提升寻找最优路径的效率.基于栅格模型,设计了算法的执行步骤.此外,分析了不同的信息素启发因子和信息素挥发系数对算法路径长度、迭代次数和收敛速度的影响.最后仿真验证了该算法优于基本蚁群算法,也得出了信息素启发因子参数选择的合理范围.     

改进自适应遗传算法在移动机器人路径规划中的应用

为了克服基本遗传算法在求解移动机器人路径规划问题中存在的收敛速度慢、易陷入局部最优等不足,该文提出了一种改进的自适应遗传算法。采用人工势场法对种群进行初始化,设计了自适应交叉和变异概率。同时,采用混合选择方式改善了基本遗传算法收敛速度慢和早熟的现象,提高了算法的进化效率。栅格环境下的仿真实验证明了该文算法在移动机器人路径规划中的可行性和有效性。     

基于广义势场的多机器人避碰算法

针对目前多机器人避碰算法存在的计算复杂、缺乏普适性等的局限性,以传统人工势场法为基础,将协商和意愿引入人工势场范畴,提出了多机器人系统运动规划的广义势场算法.该算法以物理空间障碍为基础构造排斥势场,以意愿为基础构造吸引势场,并通过排斥势场与吸引势场的拓扑积构成人工势场.在人工势场中,通过对势场中微团运动趋势的求解就可得出所需的路径规划.实验证明,该算法不仅具有人工势场法系统模型构造简单、能够进行最优路径规划的优势,而且在系统运行过程中有效地避免了系统死锁的发生.     

基于A星算法与人工势场法的无人机路径规划

为简化无人机飞行路径规划算法并提高其避障效果,本文提出一种人工势场法和A星算法相结合的路径规划算法:以人工势场法指导全局路径规划,通过引力场控制无人机的飞行方向;以A星算法指导局部路径规划,避让大型障碍物.仿真试验证明,该算法与人工势场法和A星算法相比,提高了避障效果,缩短了搜索时间.     

基于PSO的人工势场法在移动机器人路径规划中的应用

针对栅格法环境模型下PSO算法的结果是一组离散的粒子,需要通过某种准则把离散的粒子变换为连续路径的问题,提出了一种利用人工势场法把PSO规划的结果自行变换成连续路径的新方法。为了避免人工势场使机器人在障碍物附近产生震荡,采用均值滤波的方法,规划出一条平滑最优路径。仿真结果表明:该算法能比较容易地得到最优路径,有效地避免路径的震荡现象,同时也可以在变化的环境中寻找一条路径。     

采用分区场能切换法的路径规划

为解决改进人工势场法应用中出现的路径规划失败问题,提出了分区场能切换法,其包括地图标定和算法设计.先对地图中的障碍物按不同的形状进行分类标定,然后设定最小单元,设立绝对防御区和缓冲区.在不同的区域基于改进人工势场法重新设计算法,使机器人在绝对防御区只受斥力,在缓冲区受到斥力和引力,在缓冲区外只受引力,从而保证机器人往目标运动的过程中能快速靠近并成功避开障碍物.通过Matlab仿真实验,在标定好的地图中分别采用改进人工势场法和分区场能切换法,证明了所提方法的可靠性.     

基于改进遗传算法的移动机器人路径规划的研究

为改进标准遗传算法在路径规划问题中存在的初始种群可行性问题、标准遗传算子在路径规划问题上的局限性问题,文中提出了一种改进的遗传算法。首先,将环境地图转换为栅格地图,在初始种群的生成过程中加入偏移机制;然后,把人工势场算法和偏移机制分别引入交叉算子和变异算子中;最后采用动态参数的方法控制算法的遗传参数,通过改进的遗传算法对地图模型进行仿真及其求解。根据实验结果,充分验证了本文算法的有效性和实用性。实验结果明确证明了改进的算法可以很好地解决路径规划问题,为机器人的路径规划提供了一定的指导作用。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.