Deterministic uncertainty in landscapes     

Jonathan D. Phillips 《地球表面变化过程与地形》1994,19(5):389-401

Deterministic complexity (chaos) may be common in geomorphic systems, but traditional definitions may have limited practical utility for empirical geomorphology. These definitions are based on sensitivity to initial conditions, which in geomorphology are both unknown and unknowable. Further, chaos analysis depends on distinguishing deterministic complexity from stochastic complexity. This is problematic in geomorphology because some stochastic complexity is virtually always present in addition to any chaos that may be present. While it is important to recognize that some complex, apparently random patterns may derive from inherent non-linear system dynamics, this is of limited use in explaining process–response relationships or mechanics of landscape evolution. A more general term, which subsumes chaos, is deterministic uncertainty, i.e. uncertainty associated with an identifiable but unknown or uncertain source. An analysis of landscape entropy shows that such underlying constraints produce spatial patterns which are apparently chaotic. For the case of geologic controls, the apparent contribution of deterministic chaos to the landscape entropy is a direct non-linear function of the extent of geologic constraints. However, the underlying constraints and their contribution to observed spatial patterns can also be interpreted in non-chaotic terms. Examples are given, involving geologic constraints on stream channel networks and parent material control of surface soil textures. Because both randomness and chaos may be more apparent than real, the concept of deterministic uncertainty is more useful in process geomorphology than that of chaos.  相似文献   

地球化学系统的复杂性探索   总被引：10，自引：3，他引：10       下载免费PDF全文

於崇文 《地球科学》1994,19(3):283-286

地球化学系统是一种复杂系统，非平衡和非线性是导致复杂性的根源，探索复杂性就是要研究事物在非平衡条件下的非线性动力学行为，地球化学动力学是揭示地球化学系统的复杂性的有力理论工具，本文列举出锡示岩石圈系统，岩浆系统，表生系统，变质系统，断流体系统及生物有机系统的复杂性的动力学研究内容。  相似文献   

地形复杂度对坡度坡向的影响   总被引：16，自引：1，他引：16  

李天文  刘学军  汤国安 《山地学报》2004,22(3):272-277

采用三阶不带权差分算法，研究了地形复杂度与坡度坡向的关系，澄清了目前关于坡度坡向误差空间分布的矛盾观点，并分别在凹向椭球和高斯合成曲面数学模型曲面DEM上对其进行验证。通过研究得出：①坡度、坡向误差与坡度值正相关；②坡度坡向误差主要分布在平坦地区；③坡向误差较坡度误差对DEM高程数据误差敏感，较小的DEM误差引起较大的坡向误差。  相似文献   

Parallel Machine Problems with a Single Server and Release Times     

SHILing 《地球空间信息科学学报》2005,8(2):148-151

Parallel machine problems with a single server and release times are generahzatlons ot classical parallel machine problems. Before processing, each job must be loaded on a machine, which takes a certain release times and a certain setup times. All thesesetups have to be done by a single server, which can handle at most one job at a time. In this paper, we continue studying the complexity result for parallel machine problem with a single and release times. New complexity results are derived for special cases.  相似文献   

The complexity feature of crust-mantle boundary in Zhangbei seismic region and its tectonic implication   总被引：1，自引：0，他引：1  

赖晓玲  张先康孙译 《地震学报(英文版)》2006,19(3):243-250

The ProP waveform data obtained from a deep seismic sounding profile, which ran through Zhangbei seismic region, were processed by means of both seismic wave complexity coefficient and frequency spectrum analysis methods, and the complexity characteristics of crest-mantle boundary beneath the studied area and its adjacent region were determined. The results show that the place below epicenter can be taken as boundary, the northern side of which is Inner Mongolia axis with small complexity coefficient and the southern side of which is Huai＇an basin with large complexity coefficient. The different spectrum patterns at the two sides of the epicenter were inferred from spectrum analysis. In the epicentral area, there have been multi-period magmatic eruptions since Meso-Cenozoic and craters exist at the surface. From the velocity imaging of middle and upper crust in Zhangbei seismic region it can be found that there are crustal low velocity bodies around the craters and also there are low velocity zones, which went into deep crust. It is suggested that the distinct zones of crust-mantle boundary complexity may be the margin, where the magma had intruded due to magma activity in Meso-Cenozoic. The southern side with large complexity coefficient is deep magmatic activity area and the northern side with small complexity coefficient is stable crust-mantle tectonics. The difference of crust-mantle complexity provides deep background for the development of strong earthquake.  相似文献   

A comparison of drainage networks derived from digital elevation models at two scales   总被引：2，自引：0，他引：2  

Xinhao Wang  Zhi-Yong Yin 《Journal of Hydrology》1998,210(1-4):221-241

Automated generation of drainage networks has become increasingly popular with powerful analytical functions in geographic information systems (GIS) and with the increased availability of digital elevation models (DEMs). This paper compares drainage networks derived from DEMs at two scales, 1:250 000 (250K) and 1:24 000 (24K), using various drainage parameters common in hydrology and geomorphology. The comparison of parameters derived from the 250K DEMs with those from the 24K DEMs in 20 basins ranging from 150 to 1000 km² in West Virginia shows that the goodness-of-fit between parameter estimates based on the DEMs varies. Results clearly show that superior estimations are produced from the 24K DEMs. Better estimates can be obtained from the 250K DEMs for stream length and frequency parameters than for gradient parameters. However, the estimation of the mean gradient parameters based on the 250K DEMs seems to improve with increasing terrain complexity. Finally, basin size does not strongly affect the accuracy of parameter estimates based on the 250K DEMs.  相似文献   

Identification of seismic events based on stochastic properties of the short-period records     

G.R. Dargahi-Noubary 《Soil Dynamics and Earthquake Engineering》1998,17(2):101-115

Discrimination between underground nuclear explosions and natural earthquakes is considered based on a nonstationary stochastic model which incorporates a well-known deterministic formulation. Using the relevant parameters in the model a discriminating procedure is described and its application is illustrated using available P-wave records. A formal definition is presented for a geophysical feature known as ‘complexity’ and its relationship to the best linear discriminant function is pointed out. Considering the possibility of a two-dimensional discriminant, a second discriminating method based on seismic moments is considered and reasons for its appropriateness are presented. Using number of zero-crossings, a simple and computationally convenient estimator is introduced for the second discriminant. Some discussion concerning application of these techniques together with a detailed explanation concerning relationship between crossings of the original continuous records and their digitized version is also included.  相似文献   

Study on correlativity among capacity dimension D ₀, information dimension D ₁, algorithmic complexity C ( n ) and b value     

Wei-Bin Han  Gui-Xi Yi  Hua Xin 《地震学报(英文版)》1998,11(4):507-510

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Complexity and Self-Organized Criticality of Solid Earth System(Ⅱ)     

Yu Chongwen Faculty of Earth Sciences  China University of Geosciences  Wuhan 《中国地质大学学报(英文版)》1998,9(1)

ＱＵＡＮＴＩＴＡＴＩＶＥＤＹＮＡＭＩＣＳＴＲＡＴＩＧＲＡＰＨＹ（ＱＤＳ）Ｄｕｒｉｎｇｔｈｅｐａｓｔｆｅｗｄｅｃａｄｅｓｉｎｄｅｐｅｎｄｅｎｔｓｔｕｄｉｅｓｏｆｓｅｄｉ－ｍｅｎｔａｒｙｂａｓｉｎｓｗｅｒｅｃａｒｒｉｅｄｏｕｔａｌｏｎｇｄｉｆｅｒｅｎｔａ...  相似文献   

河南及邻区中等地震前地震活动性异常     

王文旭  谢智 《华南地震》1997,17(3):34-39

采用“八五”地震预报攻关研究成果－－地震算法复杂性Ｃ（ｎ）值及地震强度因子Ｍｆ值时间扫描，对河南及邻区１２次中等以上地震进行单项和综合分析研究。结果表明，对应率达８０％，显示出这些方法具有一定的预报意义。  相似文献