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1.
为了提高滑坡灾害预报准确率,改善传统的滑坡监测和预报中存在的参数选取困难及模糊控制系统作为预报模型精确度不高的问题,首先采用山体结构稳定性分析法进行滑坡灾害参数的选取,得出降雨量、含水率、土压力及岩土表面位移增量作为预报参数的结论;其次将选取的参数作为模糊系统的输入,建立滑坡灾害发生概率模型,并引入优化的GD算法修正预报模型中的动态参数,使模糊控制模型具有自适应性;同时与未优化的模糊控制模型以及单独模糊控制模型进行仿真对比,仿真结果表明,该控制算法收敛速度快,具有很好的收敛性;最后将该模型在某滑坡重点灾区实验区进行实验测试,实验结果显示该模型具有较好的收敛性,且预报精度达到90%。 相似文献
2.
为了探究X80钢制管过程中应变强化规律及其影响因素,采用厚度22 mm不同厂家生产的6种X80热轧钢板,以相同的JCOE制管工艺生产出 Φ1 219 mm×22 mm规格钢管,并对6种钢板的拉伸性能以及钢板、钢管拉伸性能差异进行了检测。根据检测结果,从化学成分、显微组织等方面分析了制管前后拉伸性能变化的影响因素。分析结果显示,X80钢制管后屈服强度、屈强比有较大幅度的升高,不同材料的升高幅度不同。研究表明,拉伸性能的变化与合金成分无明显的规律,主要与显微组织有关。 相似文献
3.
《岩石力学与岩土工程学报(英文版)》2020,12(3):630-641
Structure is an evident determinant for macroscopic behaviors of soils. However, this is not taken into account in most constitutive models, as structure is a rather complex issue in models. For this, it is important to develop and implement simple models that can reflect this important aspect of soil behavior. This paper tried to model structured soils based on well-established concepts, such as critical state and sub-loading. Critical state is the core of the classic Cam Clay model. The sub-loading concept implies adoption of an inner (sub-loading) yield surface, according to specific hardening rules for some internal strain-like state variables. Nakai and co-workers proposed such internal variables for controlling density (ρ) and structure (ω), using a modified stress space, called tij. Herein, similar variables are used in the context of the better-known invariants (p and q) of the Cam Clay model. This change requires explicit adoption of a non-associated flow rule for the sub-loading surface. This is accomplished by modifying the dilatancy ratio of the Cam Clay model, as a function of the new internal variables. These modifications are described and implemented under three-dimensional (3D) conditions. The model is then applied to simulating laboratory tests under different stress paths and the results are compared to experiments reported for different types of structured soils. The good agreements show the capacity and potential of the proposed model. 相似文献
4.
In the current article, the influence of three different doses of gamma-rays on the thermally assisted crystal growth in a novel ternary chalcogenide glassy Se78Te20Sn2 semiconductor has been reported in terms of the re-crystallization. The iso-conversional kinetic approach is used in the present study. The variation of crystal growth rate with temperature obeys the Arrhenius relation for all the doses of gamma-rays irradiation. Further analysis confirms that pre-factor K0 of crystal growth rate and the corresponding energy ΔE involved in thermally governed crystallization follows Meyer-Neldel compensation rule (MNCR). Further, we have observed a linear correlation i.e., Further Meyer-Neldel compensation rule (FMNCR) between Meyer-Neldel pre-factor K00 and Meyer-Neldel energy kT0. The observed correlations between these significant parameters (MNCR between K0 & ΔE and FMNCR between K00 & kT0) may open a new gateway for revealing the external effects on crystal growth rate during the iso-conversional analysis of crystallization kinetics. 相似文献
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6.
Employing an effective learning process is a critical topic in designing a fuzzy neural network, especially when expert knowledge is not available. This paper presents a genetic algorithm (GA) based learning approach for a specific type of fuzzy neural network. The proposed learning approach consists of three stages. In the first stage the membership functions of both input and output variables are initialized by determining their centers and widths using a self-organizing algorithm. The second stage employs the proposed GA based learning algorithm to identify the fuzzy rules while the final stage tunes the derived structure and parameters using a back-propagation learning algorithm. The capabilities of the proposed GA-based learning approach are evaluated using a well-examined benchmark example and its effectiveness is analyzed by means of a comparative study with other approaches. The usefulness of the proposed GA-based learning approach is also illustrated in a practical case study where it is used to predict the performance of road traffic control actions. Results from the benchmarking exercise and case study effectively demonstrate the ability of the proposed three stages learning approach to identify relevant fuzzy rules from a training data set with a higher prediction accuracy than alternative approaches. 相似文献
7.
A proposed expert system for word sense disambiguation: deductive ambiguity resolution based on data mining and forward chaining 下载免费PDF全文
One of the major issues in the process of machine translation is the problem of choosing the proper translation for a multi‐sense word referred to as word sense disambiguation (WSD). Two commonly used approaches to this problem are statistical and example‐based methods. In statistical methods, ambiguity resolution is mostly carried out by making use of some statistics extracted from previously translated documents or dual corpora of source and target languages. Example‐based methods follow a similar approach as they also make use of bilingual corpora. However, they perform the task of matching at run‐time (i.e. online matching). In this paper, by looking at the WSD problem from a different viewpoint, we propose a system, which consists of two main parts. The first part includes a data mining algorithm, which runs offline and extracts some useful knowledge about the co‐occurrences of the words. In this algorithm, each sentence is imagined as a transaction in Market Basket Data Analysis problem, and the words included in a sentence play the role of purchased items. The second part of the system is an expert system whose knowledge base consists of the set of association rules generated by the first part. Moreover, in order to deduce the correct senses of the words, we introduce an efficient algorithm based on forward chaining in order to be used in the inference engine of the proposed expert system. The encouraging performance of the system in terms of precision and recall as well as its efficiency will be analysed and discussed through a set of experiments. 相似文献
8.
The n-type thermoelectric Bi1.9Lu0.1Te3 was prepared by microwave-solvothermal method and spark plasma sintering. The magnetic field and temperature dependences of transverse magnetoresistance measured within temperature 2–200 K interval allow finding the peculiarities characteristic for strongly disordered and inhomogeneous semiconductors. The first peculiarity is due to appearance of linear-in-magnetic field contribution to the total magnetoresistance reflected in a crossover from quadratic magnetoresistance at low magnetic fields to linear magnetoresistance at high magnetic fields. The linear magnetoresistance can result from the Hall resistance picked up from macroscopically distorted current paths due to local variations in stoichiometry of the compound studied. The second peculiarity is that both linear magnetoresistance magnitude and crossover field are functions of carrier mobility which is in agreement with the Parish and Littlewood model developed for disordered and inhomogeneous semiconductors. An increase in the mobility due to a decrease in temperature is accompanied by an increase in the magnetoresistance magnitude and a decrease in the crossover field. Finally, the third peculiarity is related to the remarkable deviation of the total magnetoresistance measured at various temperatures from the Kohler's rule. Presence of strong inhomogeneity and disorder in the Bi1.9Lu0.1Te3 structure concluded from the magnetoresistance peculiarities can be responsible for the remarkable reduction in the total thermal conductivity of this compound. 相似文献
9.
基于形式美对比法则、均衡法则、韵律法则的内涵及其在针织面料设计中的应用规律,从深浅、虚实、肌理、曲直、高低等视角选取典型案例对针织面料进行分析,得出针织面料在形式上具有的独特意趣与艺术价值,并探讨其形式美及审美意义。通过分析针织技术与形式美法则之间的关联,探寻针织面料中形式美法则的作用及其基本规律与原理,以此指导针织面料的设计,为现代设计师灵活运用形式美法则进行艺术创作提供一定的参考。 相似文献
10.
为了解开采过程中,急倾斜且具有水平裂隙发育的上覆岩层运移规律和特点,使用PFC3D软件建立该条件下的岩层模型,并进行了开采过程模拟。利用PFC3D中的JSET和Bonds模拟了非连续和连续性的岩体构造形式。模拟结果表明:上覆关键层下部始终不出现拉力,而是沿着急倾斜构造面产生裂隙,同时在开采面附近上覆成层岩体构造面存在较大的剪切错动,但整体仍然稳定。对开采过程产生的岩体最大颗粒位移量和地表最大沉降量进行定量分析,分别得到了这两个变量与走向方向推进长度的多项式函数关系。定量分析也证明了与模拟过程分析类似的结果。 相似文献