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1.
针对目前公路选线存在的问题,提出运用本体的思想来表达选线领域知识。通过对公路选线领域知识的分析和归纳,构建公路领域知识的三层体系结构。并通过本体建模工具prot間?建立公路选线知识库。选线领域本体是对选线领域知识进行形式化描述,这种形式化描述是知识可以得到重用和共享。对于智能化选线的实现具有重要意义。  相似文献   

2.
段霞忠 《科技信息》2009,(2):244-244
本文探讨了公路建设选线中的常见地质灾害对公路建设选线的危害与影响。提出了正确认识地质条件与公路选线的关系;把握三个选线环节,科学合理选线;重视地质勘测,采取积极的应对措施的选线应对策略。  相似文献   

3.
介绍了西北黄土地区地形地貌特点,提出了公路选线的一般性原则,结合多年工作经验及体会,针对西北黄土地区,阐述了公路选线及公路美学与景现设计的方法,为今后的西北黄土地区公路选线工作提供了参考.  相似文献   

4.
针对公路自动选线交点搜索区域有限、评价方法不足等问题,基于遗传算法,通过构建公路线形约束模型、公路自动选线优化模型及运行速度预测模型,实现了公路三维空间选线方案自动寻优与安全性评价。结果表明:基于遗传算法的公路自动选线与安全评价方法,可以在给定的设计区域、拟定的技术、经济和安全条件下,克服路线交点只能在给定断面寻优的不足,实现设计方案的自动收敛和优化。在考虑路线安全性条件下,可以保证路线交点在拟定的选线区域全局进行自动搜索,验证了基于遗传算法的公路自动选线方法的可行性,并提升了选线工作的效率。该方法可以实现以速度一致性为指标的道路线形安全性评价,提高了选线方案的安全性设计水平。研究结果可为完善公路自动选线的理论基础,继续开展公路选线自动寻优方法的研究提供借鉴。  相似文献   

5.
王世槐  何定举 《科技信息》2011,(17):I0337-I0337,I0380
通过对山区公路中的沿溪线,越岭线,山脊线的选线基本方法和理论的分析,总结归纳出日前山区公路选线中存在的问题.并就问题提出初步的解决措施。同时,文章还对影响选线的多种因素进行分析,并概括出在山区公路选线应遵循的一些原则。  相似文献   

6.
本文分析了公路路线方案选择的特点,提出了公路路线方案选择的原则和步骤,研究了路线方案选择方法,包括生态选线和安全选线,提出了安全选线的标准。这些方法的提出,为设计人员在选线过程中合理协调各种影响因素、解决设计主要矛盾提供了有益的参考。  相似文献   

7.
山区改建公路在选线时需注意的几个主要问题,包括选线的原则,选线的方法及步骤,平面线形的设计及优化。  相似文献   

8.
山区改建公路在选线时需注意的几个主要问题,包括选线的原则,选线的方法及步骤,平面线形的设计及优化.  相似文献   

9.
概述了山区公路选线的技术点,分析了选线及实行放坡中应注意的几个问题。  相似文献   

10.
本章通过介绍山区公路改建的特点,详细的说明选线时所遇到的主要问题,并阐述针对问题所需采取的相应对策,还进一步介绍山区公路选线的原则.方法等。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
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.  相似文献   

14.
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。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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