基于高斯过程机器学习算法的矿柱稳定性分析

矿柱是地下矿山支撑顶板围岩、维持采场稳定的关键结构要素。为迅速准确地判别矿柱稳定性,选取矿柱宽度、矿柱高度、矿柱宽高比、矿岩单轴抗压强度和矿柱承受载荷作为影响指标,利用高斯过程机器学习算法建立矿柱状态与其主要影响因素之间的非线性映射关系,进而提出一种基于高斯过程二元分类(GPC)的矿柱状态识别模型。结合工程实例,以40组样本数据进行训练,以10组样本数据对该模型进行检验,并与ANN和SVM进行对比。结果表明,矿柱状态识别的高斯过程模型是科学可行的,该模型具有参数自适应化获取、分类精度高、计算复杂度低等优点,还可对矿柱状态判别结果的不确定性或可信度进行定量化评价。     

多维地震作用下偏心结构动力反应的Simulink仿真分析

理论研究与震害经验表明,地震时结构会产生不可忽略的平动与扭转耦合的空间振动,因此,对结构进行平—扭耦联反应分析具有重要意义。本文首先建立多维地震动作用下偏心结构的空间力学模型和动力方程,并编制相应的MAT LAB程序,然后将动力方程所代表的动力学系统用控制理论中的状态空间法予以描述,根据其状态方程在SIMULINK环境下建立仿真分析模型,从而求解动力方程。对一双向水平地震作用下的6层偏心框架结构进行平—扭耦联反应数值仿真分析,得出了一些有益的结论。     

中国城市工业污染强度与经济增长耦合关系

利用幂函数模型对中国46个重点城市1993-2006年人均GDP和7项工业污染强度指标进行曲线拟合,用于描述和分析我国城市经济发展与工业污染强度的耦合状态,经模型推导提出了“效率弹性系数”,作为度量城市经济与工业污染控制协调发展程度的指标。拟合统计结果显示,中国城市工业污染强度与经济增长的关系曲线形状有明显的幂函数特征。样本城市在“曲线簇”中的位置能揭示“后发优势”以及经济-环境耦合水平优劣的信息。对样本城市效率弹性系数的统计分析证明,该系数可以作为城市经济环境管理的决策依据。     

Ontogenetic States,Effective Density,and Classification of Plant Populations

Uranov (1975) formulated a theory of the age structure of plant populations and, in particular, defined the index of ageness . On the basis of this theory, the concepts of the energy efficiency of plants in a certain ontogenetic state and the average efficiency of a population () are introduced. A new classification of populations with respect to the types of age structure is proposed which is based on both the and values and, accordingly, is named the delta–omega classification. The notion of effective population density is defined. This parameter takes into account different loads of plants in different ontogenetic states on the environment and is quantitatively equal to the product of the population density and . The proposed approaches and methods are illustrated by data on the distribution of age states in different plant species.     

INTERVENTION ANALYSIS OF WATER QUALITY RECORDS1

The impoundment of the Kootenai River by Libby Dam caused changes in discharge and water quality in the river downstream from Lake Koocanusa. The changes observed downsteam were largely attributable to the depth of withdrawal from the reservoir and the reservoir's ability to store and mix various influent water masses. The preimpoundment and postimpoundment time series of discharge and six water quality variables were autocorrelated and exhibited strong seasonality. Intervention analysis, a technique employing Box-Jenkins time series models, was used to quantify the nature and magnitude of the changes in water quality after the construction of Libby Dam. The models were developed with data from June 1967 through February 1981 and were able to satisfactorily forecast riverine conditions from March 1981 through January 1982.     

THE CONTINUING EVOLUTION OF AN AUSTRALIAN WATER RESOURCES POLICY1

ABSTRACT: Australia's extremely limited water resources highlight the need for policy guidelines for management. During the 1970s, there was the gradual evolution of a national water resources policy, facilitated by a nationally agreed statement of objectives and culminating in a federal policy statement presented in 1979. However, the Australian constitution gives major responsibility for water resources to the states. Further, the federal policy statement seems to assume that each state has a water resources policy and that it accords with the nationally agreed objectives. This is not the case, and the practical management of Australia's water resources falls short of the principles set out in the policy document. The River Murray, the nation's major water resource, provides ample evidence of this fact. With very limited water resources, Australia urgently needs to reduce the disparity between principle and practice in their management.     

A MATRIX AND ACCOMPANYING CLASSIFICATIONS FOR IDENTIFYING WATER RESEARCH PROBLEMS AND NEEDS1

ABSTRACT: A matrix was developed of problems with the functional use of water resources (rows) and functions served by water resources research (columns). A classification of water problems and a classification of research fields also were developed to accompany the matrix. The matrix and classification schemes were used when preparing the five-year research and development plan of the Water Resources Center of The Ohio State University. They were used: (1) to classify each research project that had been supported by the Water Resources Center from 1965 through 1980, (2) to guide interviews with personnel of federal and state agencies and university faculty who assisted in defining Ohio's water research needs, (3) to organize responses received during these interviews, and (4) to arrive at a selected list of ten problems with the functional use of Ohio's water resources that were prioritized based upon opinions received from water-related officials throughout the state. Other matrices and classification schemes are reviewed that were revised and expanded upon when formulating the ones used in Ohio. Suggestions are given regarding further development of the functional matrix and accompanying classifications as well as their use in administration of the cooperative federal-state water resources research program and other federal water resources research programs.     

CAN STATE AND LOCAL GOVERNMENTS ASSUME MORE OF THE COSTS OF WATER DEVELOPMENT?1

ABSTRACT As availability of funds in the federal budget for water development has decreased recently, pressure has increased for state and local governments to pay a larger share of the costs. In this situation a difficult question immediately arises-what is the capability of state and local governments to pay a larger share? Of course, there is no easy answer. Expenditures of public funds are policy outcomes of a government's political process in which political, economic, legal and other factors are involved in complex relationships. The traditional sources of capital funds for state and local governments include bond proceeds, tax revenues, and federal financial aid (state aid is also a major source of local government funds). The issuing of bonds is hampered by a variety of legal debt limitations, but there are means for circumventing the limitations. State and local governments vary widely in amounts of taxable resources available and in the extent to which these resources have been tapped. More effective use of revenue resources could be made in some cases. New sources of capital funds for water development ought to be considered-a fee on the use of water per se, for example. Costs associated with water use currently are imposed to cover development costs, but a state might impose additional use fees earmarked for a state water development fund.     

CHLOROPHYLL,PHOSPHORUS, SECCHI DISK,AND TROPHIC STATE1

ABSTRACT: The relationship between chlorophyll u, total phosphorus, secchi disk depth, and trophic state were examined using data on U.S. lakes collected by U.S. EPA's National Eutrophication Survey. By comparing predicted secchi disk depths with observed summer secchi disk depths in 757 lakes, it was determined that in many lakes non-chlorophyll related light attenuation is important in controlling the amount of chlorophyll u produced per unit of total phosphorus. Ranking of 44 lakes by 18 different trophic state measurements and single and multivariable indices were compared with rankings provided by mean summer ambient total phosphorus and chlorophyll u. The trophic state measurements and indices were much more successful in ranking the lakes against total phosphorus than chlorophyll u, indicating that there are differences in the relative trophic rankings of many of the lakes depending upon whether primary nutrients or biological manifestations are used as the ranking mechanism. If the manifestations of nutrients rather than their absolute levels are the primary criteria for beneficial use of lakes, the use of many of the commonly employed trophic state measurements, which assume or imply that there is a constant relationship between total phosphorus or secchi disk and chlorophyll, can lead to erroneous conclusions and unnecessary costly management controls. Secchi disk measurements may be more useful as a predictor of ambient lake total phosphorus concentrations than of chlorophyll.     

Using Differences Among Carlson's Trophic State Index Values in Regional Water Quality Assessment1

ABSTRACT: Variation among Carlson's three TSI values is unsettling to both the public and the scientific communities. Currently, there is no systematic way to account for differences in the three TSI values. Either (or both) of two mechanisms are proposed to account for differing TSI values on a regional basis. The first mechanism simply transforms the Secchi disk and phosphorus information to conform to their respective regional relationship with chlorophyll. The second mechanism uses the three TSI values to identify modifying processes in a lake and may indicate which TSI value (or combination of values) best reflects a lake's trophic condition. The format that is being proposed using information collected from 60 lakes in the Twin Cities (Minnesota) Metropolitan Area can be applied to other regional situations.