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31.
32.
船舶碰撞距离直接影响船舶碰撞危险度的大小。分析了影响船舶碰撞距离的因素:会遇 态势、船舶的操纵性能、船舶尺度、船舶速度等;给出目标船静止不动时和目标船有运动速度时的 船舶转向避让时碰撞距离数学模型,为研究船舶碰撞危险度和船舶自动避碰决策系统提供理论依 据。 相似文献
33.
影响力传播模型IDM用于挖掘和分析BBS上观点领袖以及热门话题,它主要以影响力作为衡量标准。通过简化影响力运算法则,对IDM模型进行改进,使其更加直观。此改进后的IDM模型可运用到社会网络中,能更深刻的揭示出社会网络中各通信个体间的相互影响和距离,从而更好地了解和研究社会网络。 相似文献
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This paper introduces a GIS-based toolbox, called SAINF, for analyzing the effects of infrastructural features on the distribution of non-infrastructural features. One of the distinct characteristics of SAINF is that it can deal not only with point-like infrastructural features but also line-like (e.g. railways) and polygon-like (e.g. big parks) features. SAINF analyzes these effects with the conditional nearest neighbor distance method and the cross K-function method. First, the paper briefly refers to these methods. Second, the paper illustrates how to use SAINF with an actual example. SAINF can be downloaded via the Internet without charge for non-profit uses.We express our thanks to Exceed Co. Ltd. for helping us program SAINF, and to Miki Arimoto for making the data of high-class apartment buildings and parks in Kiba. This development was partly supported by Grant-in-aid for Scientific Research No. 10202201 (Spatial information science for human and social sciences) and No. 14350327 (Regional supporting network planning for the elderly) by the Ministry of Education, Culture, Sports, Science and Technology of Japan. 相似文献
36.
分析了高斯距离加权格网法计算应变率的原理和特征,研制了相应的计算程序,并用于华北地区现今地壳应变特征研究。基于华北地区1999~2009年的GPS观测结果,研究了确定高斯平滑半径的原则和方法,并给出华北地区地壳形变多个应变率物理量的分布。结果表明,基于150 km高斯平滑半径计算水平速度梯度能够较好地分辨华北地区的应变率空间变化特征,首都圈地区地壳以张渤带上的左旋剪切为主,其中唐山-秦皇岛地区同时存在南北向的拉张变形;山西带整体表现为沿断裂的右旋剪切变形,同时兼具“南挤北张”特性;郯庐断裂带整体形变特征不显著,在南北两端局部区域存在较小的剪切形变;鄂尔多斯块体内部比较稳定,北缘以拉张和左旋剪切变形为主,西缘表现为左旋剪切以及EW向的挤压特征,南缘的秦岭块体南北两侧分别具有左旋剪切和右旋剪切的特性,东西两侧分别表现为正断拉张与逆断挤压特征。 相似文献
37.
Eihan Shimizu 《International journal of geographical information science》2013,27(11):1453-1470
A distance cartogram is a diagram that visualizes the proximity indices between points in a network, such as time–distances between cities. The Euclidean distances between the points on the distance cartogram represent the given proximity indices. This is a useful visualization tool for the level of service of transport, e.g. difference in the level of service between regions or points in a network and its improvement in the course of time. The two previously proposed methods—multidimensional scaling (MDS) and network time–space mapping—have certain advantages and disadvantages. However, we observe that these methods are essentially the same, and the merits of both these methods can be combined to formulate a generalized solution. In this study, we first formulate the time–space mapping problem, which includes the key features of both of the above stated methods, and propose a generalized solution. We then apply this solution to the time–distances of Japan's railway networks to confirm its applicability. 相似文献
38.
Michael Feast Patricia Whitelock John Menzies 《Monthly notices of the Royal Astronomical Society》2002,329(1):L7-L12
A globular cluster distance scale based on Hipparcos parallaxes of subdwarfs has been used to derive estimates of M K for cluster Miras, including one in the Small Magellanic Cloud (SMC) globular cluster NGC 121. These lead to a zero-point of the Mira infrared period–luminosity (PL) relation, PL( K ), in good agreement with that derived from Hipparcos parallaxes of nearby field Miras. The mean of these two estimates together with data on LMC Miras yields a Large Magellanic Cloud (LMC) distance modulus of in evident agreement with a metallicity-corrected Cepheid modulus .
The use of luminous asymptotic giant branch (AGB) stars as extragalactic population indicators is also discussed. 相似文献
The use of luminous asymptotic giant branch (AGB) stars as extragalactic population indicators is also discussed. 相似文献
39.
N. Tikhonov 《Astronomische Nachrichten》1996,317(3):175-178
A photometry in the V, R, I (Cousins) system has been performed for stars in the galaxy Cassiopeia 1. The resulting colour-agnitude (CM) diagram of Cas 1 reveals the existence of blue stars and the absence of red ones. From an analysis of the CM diagram of the galaxy it is concluded that Av = 4.0 mag, and the distance modulus (m – M)o = 24.5 mag, corresponding to a distance of 790 kpc. The visual magnitude of the galaxy is V = 14m.62 (Mv = −13m.8) and the colour index (V – R) = 0.89 mag. From the distance determination the galaxy Cassiopeia 1 is a member of the Local group. 相似文献
40.
It is well established that sea surface temperature (SST) plays a significant role in the hydrologic cycle in which precipitation is the most important part. In this study, the influence of SST on Indian subdivisional monthly rainfall is investigated. Both spatial and temporal influences are investigated. The most influencing regions of sea surface are identified for different subdivisions and for different overlapping seasons in the year. The relative importance of SST, land surface temperature (LST) and ocean–land temperature contrast (OLTC) and their variation from subdivision to subdivision and from season to season are also studied. It is observed that LST does not show much similarity with rainfall series, but, in general, OLTC shows relatively higher influence in the pre‐monsoon and early monsoon periods, whereas SST plays a more important role in late‐ and post‐monsoon periods. The influence of OLTC is seen to be mostly confined to the Indian Ocean region, whereas the effect of SST indicates the climatic teleconnection between Indian regional rainfall and climate indices in Pacific and Atlantic Oceans. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献