Some Classes of Kenmotsu Manifolds with Respect to Semi-symmetric Metric Connection

In this paper, we study conharmonic curvature tensor in Kenmotsu manifolds with respect to semi-symmetric metric connection and also characterize conharmonically flat, conharmonically semisymmetric and Ф-conharmonically flat Kenmotsu manifolds with respect to semi-symmetric metric connection.

ON SEMI-SYMMETRIC RECURRENT-METRIC S-CONCIRCULAR CONNECTIONS

ＯＮＳＥＭＩ－ＳＹＭＭＥＴＲＩＣＲＥＣＵＲＲＥＮＴ－ＭＥＴＲＩＣＳ－ＣＯＮＣＩＲＣＵＬＡＲＣＯＮＮＥＣＴＩＯＮＳ￥ＬｉａｎｇＹｉｘｉｎｇ（ＤｅｐｔｏｆＭａｔｈ，ＸｉａｍｅｎＵｎｉｖ．Ｘｉａｍｅｎ３６１００５）Ａｂｓｔｒａｃｔ：Ｉｎｔｈｉｓｐａｐｅｒ，...

ISOTROPIC WEYL MANIFOLD WITH A SEMI-SYMMETRIC CONNECTION

In this work,it is proved that every isotropic Weyl manifold with a semi- symmetric connection is locally conformal to an Einstein manifold with a semi-symmetric connection.

Chen’s Inequalities for Submanifolds in (<i>&kgreen;, &#181</i>)-Contact Space Form with a Semi-Symmetric Non-Metric Connection

In this paper, we obtain Chen’s inequalities in (k,?μ)-contact space form with a semi-symmetric non-metric connection. Also we obtain the inequalites for Ricci and K-Ricci curvatures.

Some Properties of <i>CR</i>-Submanifolds of a Nearly Trans-Sasakian Manifold with a Semi Symmetric Non-Metric Connection

This paper deals with the study of CR-submanifolds of a nearly trans-Sasakian manifold with a semi symmetric non-metric connection. Nijenhuis tensor, integrability conditions for some distributions on CR-submanifolds of a nearly trans-Sasakian manifold with a semi symmetric non- metric connection are discussed.

ON THE CHERN CONNECTION OF FINSLER SUBMANIFOLDS

This paper studies the induced Chern connection of submanifolds in a Finsler manifold and gets the relations between the induced Chern connection and the Chern connection of the induced Finsler metric. Then the authors point out a difference between Finsler submanifolds and Riemann submanifolds.

Some Connections in Almost Hermitian Manifold

The idea of this research is to study different types of connections in an almost Hermite manifold. The connection has been established between linear connection and Riemannian connection. Three new linear connections ∇1, ∇2, ∇3 are introduced. The necessary and sufficient condition for ∇1, ∇2, ∇3 to be metric is discussed. A new metric s* (X,Y) has been defined for (Mn,F,g*) and additional properties are discussed. It is also proved that for the quarter symmetric connection ∇ is unique in given manifold. The hessian operator with respect to all connections defined above has also been discussed.

Adapted Metrics for a Modified Coulomb/Newton’s Potential

Modified Theories of Gravity include spin dependence in General Relativity, to account for additional sources of gravity instead of dark matter/energy approach. The spin-spin interaction is already included in the effective nuclear force potential, and theoretical considerations and experimental evidence hint to the hypothesis that Gravity originates from such an interaction, under an averaging process over spin directions. This invites to continue the line of theory initiated by Einstein and Cartan, based on tetrads and spin effects modeled by connections with torsion. As a first step in this direction, the article considers a new modified Coulomb/Newton Law accounting for the spin-spin interaction. The physical potential is geometrized through specific affine connections and specific semi-Riemannian metrics, canonically associated to it, acting on a manifold or at the level of its tangent bundle. Freely falling particles in these “toy Universes” are determined, showing an interesting behavior and unexpected patterns.

微分形式代数上的半对称不保度量联络

引入了Levi-Civita联络的半对称不保度量扰动,即微分形式代数上的半对称不保度量联络.计算了它在微分形式代数上的曲率张量及其Ricci张量.研究了在微分形式代数上的分布,得到了半对称不保度量联络的Gauss-Codazzi-Ricci等式.

Assessing sediment connectivity and its spatial response on land use using two flow direction algorithms in the catchment on the Chinese Loess Plateau

Severe soil and water loss have led to widespread land degradation on the Loess Plateau in China.Exploring the relationship between land use and sediment connectivity can be beneficial to control soil erosion.In this study,three catchments in the Yanhe River Basin on the Loess Plateau were selected to analyse the relationship between land use and sediment connectivity using grey correlation method.Index of connectivity(IC)was employed to quantify sediment connectivity,including two flow direction algorithms(D8 and D-infinity)and two final targets of sediment transport(outlet and main channel of catchment).Then,11 landscape metrics were used to evaluate the land use spatial patterns of catchments.By comparing the IC value ranges,histograms and classes,and their relationship with remote sensing images of the two flow direction algorithms,we find that the D8 algorithm is more suitable for this study area.The results showed that the three catchments are characterized by high sediment connectivity in the grassland and forest close to the channel.In addition,the roads and bare land close to the channel also have high or medium sediment connectivity.Grey correlation analysis showed that landscape division index(DIVISION),fractal dimension index(FRACMN),aggregation index(AI),total class area,patch cohesion index(COHESION),and largest patch index(LPI)indices were the main factors that affect sediment connectivity at the class scale.At the landscape scale,the landscape shape index(LSI),Shannon’s diversity index(SHDI),and gully density have an essential effect on sediment connectivity.This condition provides a way to control the sediment connectivity in the watershed by transforming land use type or changing its spatial pattern,but specific adjustment measures have to be further explored.

On the Local Connected and Jordanian Julia Sets

In this article,we investigate the dynamical properties of fλ(z)=λzkez,for λ(≠0)∈C and k≥2.We will show that the boundaries of some (or all) Fatou components are Jordan curves and the Julia sets are Sierpinski carpet,and they are locally connected for some certain λ.

定位与通信受限的网联协同感知算法

随着车联网通信技术的不断发展,协同感知的网联自动驾驶成为未来智慧交通系统中重要的组成部分,可有效解决传统单车智能在感知和计算能力上的固有局限.然而,现有的协同感知算法大多依赖准确的定位信息进行多视角融合,往往忽略通信带宽与通信时延的约束.因此,文中提出面向定位与通信受限条件下的特征层级协同感知算法,在不依赖准确位置与位姿信息的情况下实现不同视角信息的匹配,同时对通信时延具有一定的鲁棒性,能根据信道状态动态调整通信数据量.文中算法结合传统两阶段感知范式与深度度量学习,通过传输区域特征图进行跨视角信息匹配,降低定位误差和通信时延带来的影响.同时,通过车联网通信传输的区域特征图数量可以实时在线调整通信数据量,满足不同信道条件的约束.在协同感知数据集上的实验表明,文中算法在各场景下均表现出显著的协作增益,在一定通信时延下感知精度不显著衰减,可有效降低所需传输的数据量.

Notes concerning Codazzi pairs on almost anti-Hermitian manifolds

Let∇be a linear connection on a 2n-dimensional almost anti-Hermitian manifold M equipped with an almost complex structure J,a pseudo-Riemannian metric g and the twin metric G=g◦J.In this paper,we first introduce three types of conjugate connections of linear connections relative to g,G and J.We obtain a simple relation among curvature tensors of these conjugate connections.To clarify the relations of these conjugate connections,we prove a result stating that conjugations along with an identity operation together act as a Klein group,which is analogue to the known result for the Hermitian case in[2].Secondly,we give some results exhibiting occurrences of Codazzi pairs which generalize parallelism relative to∇.Under the assumption that(∇,J)being a Codazzi pair,we derive a necessary and sufficient condition the almost anti-Hermitian manifold(M,J,g,G)is an anti-K¨ahler relative to a torsion-free linear connection∇.Finally,we investigate statistical structures on M under∇(∇is a J−parallel torsion-free connection).

Certain Curvature Conditions on P-Sasakian Manifolds Admitting a Quater-Symmetric Metric Connection

The authors consider a quarter-symmetric metric connection in a P-Sasakian manifold and study the second order parallel tensor in a P-Sasakian manifold with respect to the quarter-symmetric metric connection. Then Ricci semisymmetric P-Sasakian manifold with respect to the quarter-symmetric metric connection is considered. Next the authors study ξ-concircularly flat P-Sasakian manifolds and concircularly semisymmetric P-Sasakian manifolds with respect to the quarter-symmetric metric connection. Furthermore, the authors study P-Sasakian manifolds satisfying the condition Z(ξ,Y)·S=0,where Z,S are the concircular curvature tensor and Ricci tensor respectively with respect to the quarter-symmetric metric connection. Finally, an example of a 5-dimensional P-Sasakian manifold admitting quarter-symmetric metric connection is constructed.

面向大规模蜂群自组网跨层路由协议设计与仿真

针对大规模蜂群自组网中,大量路由开销导致广播风暴而严重影响通信质量的问题,设计了一种跨层路由协议。该协议对路由层和接入层进行一体化设计,利用统一连通支配集算法在接入层构建虚拟骨干网络,利用骨干网信息在网络层进行拓扑发现,引入基于模糊视觉的触发式洪泛机制,能减少节点控制信息的转发次数、缩小洪泛范围。采用基于传输时间和接收信号信噪比(signal noise ratio,SNR)的度量判据方式计算路径,实现动态网络拓扑的路由快速收敛,增强网络感知的灵敏度。仿真结果表明,与现有路由协议相比,跨层路由协议能够大幅降低网络开销,在端到端时延、吞吐量和路由建立时间方面,其性能也有显著提升。

植被格局对侵蚀产沙影响的研究评述

土壤侵蚀是人类可持续发展的重要挑战,植被重建则是防控侵蚀产沙的有效手段。在当前水土资源日益稀缺的新形势下,优化植被布局将成为黄土高原等生态脆弱地区未来阻蚀减沙、改善环境的重要途径,有关植被格局对侵蚀产沙影响的科技需求更加急迫、意义更加重要。为此,从坡面与流域两个尺度,总结评述了侵蚀产沙研究中的植被格局表征、侵蚀产沙对植被格局的变化响应两个议题的研究进展。分析认为,目前主要存在缺乏反映侵蚀产沙过程的植被格局表征指数、较少考虑植被与地形叠置格局对侵蚀产沙的耦合影响、尚未建立侵蚀产沙对植被格局的直观响应关系等问题。为促进有关研究,今后在格局指数和耦合关系的构建中应重视植被和地形对侵蚀产沙过程的耦合影响,并选用具有良好应用精度的分布式物理成因模型,以获得反映植被格局影响的流域侵蚀产沙结果。同时,可通过采用GIS空间分析技术,设计获得更多的典型植被格局及对应情景的侵蚀产沙,以丰富基础资料,减少信息干扰。

基于电气距离的复杂电网关键节点识别

深入研究电力系统复杂网络特性及连锁故障传播机理对预防大停电事故至关重要。在分析电力网潮流分布机理的基础上,针对经典复杂网络模型不能很好地结合决定网络潮流分布定律的问题,提取蕴含于电网特征参数中的物理信息,根据叠加原理计算得出电网节点间电气距离,基于电气距离提出了网络节点电气耦合连接度的概念。建立基于节点电气耦合连接度的电力系统复杂网络特性辨识模型。与已有复杂电网模型相比,该模型更符合电力系统实际。通过对IEEE标准示例系统的计算,揭示电网内在的异质结构特性,并将该指标应用于电力网关键节点识别。对IEEE 39节点系统和湖南某地区电网进行分析计算,时域仿真结果表明,所提指标比拓扑度指标更为合理有效。

车联网仿真测试评价技术研究综述

车联网的大规模部署及其在智能网联汽车领域的广泛应用前需要对其性能及功能进行全面、深入的测试评价,其中通过仿真技术对其进行评价分析是当前的主流测试评价手段。从车联网研究及应用过程中的测试评价需求出发,总结了主流的网络仿真器和交通仿真器,对现有车联网仿真平台进行了分类,研究并对比分析了典型的车联网仿真平台;针对车联网的应用特性,研究并归纳了影响车联网仿真性能的车辆移动模型、信道传播模型及驾驶员行为等;从网络仿真指标、车联网应用相关指标归纳了车联网功能及性能测试的典型评价指标;最后探讨了车联网仿真测试的发展方向。

城市潜在绿色廊道构建方法——以常州市为例

在RS和GIS的支持下,利用遥感影像分类、斑块连通性分析和耗费距离模拟等方法形成一套完整的城市潜在绿色廊道构建体系。首先采用最优指数(OIF)和决策树(QUEST算法)获取城市绿地斑块空间布局,分析绿地斑块间的连通性;然后利用Spearman秩相关等统计方法确定不同连通指数对连通阈值的敏感程度,优选最稳定的连通指数划分绿地斑块的重要性等级,将具有较高重要性值的斑块作为绿地"源"和"目标";最后选用频率比方法改进耗费距离模型的成本表面,在不同空间尺度下,情景模拟城市潜在绿色廊道的空间布局,并对模拟结果进行定量分析与评价。结果表明:最优指数结合决策树方法的分类总精度为90.35%,Kappa系数为0.86,提取绿地面积占城市总面积的22.88%,大面积绿地斑块主要分布在滆湖的西部和太湖的北部;整体连通指数(IIC)具有较高的稳定性,在200～2400m的距离范围内,其dIIC的Spearman秩相关系数变化值最低(0.21);在600m的距离阈值下,以dIIC值大于1%作为标准,确定竺山斑块为绿地"源"及7个主要的绿地斑块为"目标";在不同空间尺度下,模拟的潜在绿色廊道的变形系数ξ值相近(1.28),其空间格局受研究尺度的影响较小。最后进一步探讨该方法体系实践的可行性,为城市绿地系统规划和建设提供科学合理的参考和依据。