临汾汾西灌区龙子祠泉冬小麦非充分灌溉模式初探

在了解汾西灌区龙子祠冬小麦需水特性的基础上,结合当地的降水、地下水补给的特点,根据冬小麦非充分灌溉的灌水指标及优化运行模式,经过2000-2003三年的田间试验,该模式与当地的充分灌溉相比,在单产接近的条件下,节省了灌溉水量,提高了灌水生产率,使水资源得以充分利用.     

非充分灌溉制度设计优化模型

研究了缺水地区冬小麦灌溉问题.分析了作物模型,作物水分影响函数,并以农作物产量最大为目标,提出了非充分灌溉制度优化设计二维动态规划模型和相应的动态规划逐次逼近(DPSA)求解方法.针对山东省临沂市小埠东灌区的实际情况进行研究,求得了冬小麦三个典型年不同供水水平的最优灌溉制度、排水过程及相应产量.实例表明,模型及方法是合理的.     

水分胁迫条件下稻田优化灌溉制度的研究

本文通过对非充分灌溉条件下水稻优化灌溉制度如何制定进行了研究。其特点是将作物产量模型与耗水规律模型相结合,以相对产量最高为目标函数,建立了优化决策系统,并利用多目标规划进行求解。该研究成果可使有限的水量在作物生育期内发挥最大的效率,对优化配置水资源,实现农业高效用水具有重要作用。实例研究结果说明,所建模型及求解方法是合理与可行的,不但提高了水分利用效率,还为查哈阳灌区水资源的优化利用提供了科学依据。     

非充分灌溉在节水示范项目中的应用

代王街办是西安市临潼区有名的"水中旱"地区,属于渭河南台塬区,地下水埋深 80～200 m,单井水量 32 m3/h 左右,70 年代打成一批深井,由于配套设施不完善无法使用,当地群众只有靠天吃饭.1998 年水利部正式立项批准在该区实施高效节水增效灌溉示范项目,实施面积 0.7 万亩.工程经过近8年运行效果良好;为干旱缺水地区如何利用有限的水资源扩大灌溉面积,达到节水增产方面探索了有效途径,取得了十分显著的效果.     

基于遗传算法的优化搜索技术

遗传算法是借鉴生物界自然选择和自然遗传机制的随机化搜索算法,其主要特点是搜索不依赖于梯度信息,能自动获取和积累有关搜索空间的知识,并自适应地控制搜索过程,从而得到最优解或准最优解的通用搜索算法。它尤其适合于组合优化、机器学习、自适应控制、规划设计和人工智能等领域。     

非线性节水高产优化模型

为研究节水高产的灌溉制度,从研究作物根区土壤水运动及作物腾发规律入手,建立了一个求解作物灌溉制度的非线性优化模型.经实例验证,模型是合理可行的.     

一种基于宏启发搜索策略的神经网络学习算法

神经网络的学习是全局优化问题，Ｔａｂｕ搜索是一种非常有效的求解全局优化问题的宏启发搜索策略，文章根据Ｔａｂｕ思想和松弛原理，提出了一种多层网络学习算法。初步实验表明该方法是有效和快速的。     

河套灌区井渠联合运用优化灌溉模型

针对河套灌区的地面水与地下水联合运用问题,提出了井渠结合优化灌溉模型,以最佳种植模式和最优工程运行策略,达到控制地下水位、防治土壤盐碱化、获得农作物稳产高产的目的.模型有调蓄地面水源、土壤贮水层、地下含水层的能力.优化计算成果与266.7hm2试验示范区的实际运行结果相吻合,节水、节能、增产及控制地下水位、改良盐碱地等效果十分显著,这对发展节水型灌溉农业具有重要的现实意义.     

一种重力场下延的混合优化算法

由于地下埋藏体形态各异,影响解释效果的因素很多,在解释过程中,有些因素处理不当,不但会增加解释的工作量,更重要的是解释效果不太理想。根据带校正系数的位场下延的基本原理,从校正系数的特征分析入手,在分析校正系数对下延结果影响的基础上建立反演的数学模型,并利用混合优化算法求取计算的最初优值及其对应的校正系数取值,以使解释效果更好地反映出场源体的特征。     

A chemical equilibrium algorithm for highly non-ideal multiphase systems: Free energy minimization

A method is presented for calculating equilibrium phase assemblages in very nonideal systems. It may be applied to any system for which a thermodynamically consistent model of the free energy which satisfies the usual Maxwell relations and convexity criterion is available. The algorithm minimizes the Gibbs free energy by independently choosing stable reaction directions. The procedure is described in detail and various numerical problems encountered and strategies for dealing with them are discussed. It will be shown that the necessary and sufficient conditions for solution phase selection may be derived from the values of the Lagrange multipliers corresponding to constraints on phases that are not present in the system. The method for evaluating the solution phase Lagrangian multipliers and choosing the optimum composition with which to bring the new solution phase into the system involves a separate constrained minimization problem. This method is sufficiently general so that the correct phase assemblage is chosen free from external control. Special procedures for adding and removing phases including solution phases are also described.     

A novel algorithm for designing the layout of additional boreholes

In an exploration project, the placement of additional boreholes is based on the available information and engineering judgment, which may result in a lack of information or redundant information in decision making. This paper presents the use of dynamic multistage sampling to design directional and vertical boreholes to scan the subsurface. For this purpose, the potential collars of boreholes are determined within the survey area, while the imaginary boreholes in the form of cone sides cover the area's lateral surface area, and the concentric cones around the collars change with azimuth and dip angles. The objective function is a criterion used to determine the optimal borehole(s) and update the input borehole database in each stage; this iterative process continues until a stopping condition is satisfied. The presented algorithm was executed and validated on both synthetic and field data from the Eastern Kahang region in Iran. In the synthetic case, five additional boreholes were designated based on high grade and estimation error objectives that intersect two parts of the ore body. Ten proposed additional boreholes in the northeast region of Kahang coincided with the high grade copper mineralization zone.     

水文地质参数识别的连续禁忌搜索改进算法

水文地质参数的正确与否是构建地下水数值模型的根本,而参数寻优结果很大程度上取决于优化算法的选择。禁忌搜索算法是一种广泛应用于组合优化问题的启发式全局寻优算法,但在连续函数优化领域应用比较少。基于上述考虑,本文首先引入求解连续函数优化问题的连续禁忌搜索算法并对其进行改进,进而提出一种连续禁忌搜索改进算法(ICTS),最后将其与地下水模型耦合进行水文地质参数识别。算例研究表明,ICTS算法较其他算法(CTS,SGA,Micro-GA,PSO)求解效率提高1.87～4.64倍,求解精度提高1.08～12.86倍。因此ICTS算法在参数反演计算中求解精度高、收敛速度快、寻优性能强,是一种值得推广的水文地质参数识别方法。     

Enhancement of backtracking search algorithm for identifying soil parameters

In this paper, an enhanced backtracking search algorithm (so-called MBSA-LS) for parameter identification is proposed with two modifications: (a) modifying the mutation of original backtracking search algorithm (BSA) considering the contribution of current best individual for accelerating convergence speed and (b) novelly incorporating an efficient differential evolution (DE) as local search for improving the quality of population. The proposed MBSA-LS is first validated with better performance than the original BSA and some other typical state-of-the-art optimization algorithms on a benchmark of soil parameter identification in terms of effectiveness, efficiency, and robustness. Then, the efficiency of the MBSA-LS is further illustrated by two representative cases: identifying soil parameters from both laboratory tests and field measurements. All comparisons demonstrate that the proposed MBSA-LS algorithm can give accurate results in a short time. Finally, to conveniently solve the problems of parameter identification, a practical tool ErosOpt for parameter identification is developed by integrating the proposed MBSA-LS and some other efficient algorithms for readers to conduct the parameter identification using optimisation algorithms.     

基于模式搜索的微地震速度反演——以渤海K油田为例

无论是井间地震还是水力压裂微地震,都需要知道相对准确的地层速度,笔者提出了一种新的微地震层速度反演方法,即模式搜索算法.首先利用测井资料和地质认识建立初始速度模型,然后拾取射孔记录的地震初至时间.由于有些地震记录激发时间难以确定,因此可利用各地震道之间的时差建立目标函数,最后利用模式搜索算法寻找目标函数最优解.模型试算结果及实际资料的应用都表明,该方法对于参数较少的层状介质模型有比较好的效果,为渤海水力压裂等技术提供一定借鉴意义.     

An approximate nearest neighbors search algorithm for low-dimensional grid locations

We propose a new algorithm for the problem of approximate nearest neighbors (ANN) search in a regularly spaced low-dimensional grid for interpolation applications. It associates every sampled point to its nearest interpolation location, and then expands its influence to neighborhood locations in the grid, until the desired number of sampled points is achieved on every grid location. Our approach makes use of knowledge on the regular grid spacing to avoid measuring the distance between sampled points and grid locations. We compared our approach with four different state-of-the-art ANN algorithms in a large set of computational experiments. In general, our approach requires low computational effort, especially for cases with high density of sampled points, while the observed error is not significantly different. At the end, a case study is shown, where the ionosphere dynamics is predicted daily using samples from a mathematical model, which runs in parallel at 56 different longitude coordinates, providing sampled points not well distributed that follow Earth’s magnetic field-lines. Our approach overcomes the comparative algorithms when the ratio between the number of sampled points and grid locations is over 2849:1.     

一种基于数值应力场的强度各向异性边坡稳定性分析方法

提出了一种基于数值应力场下的边坡临界滑动面和临界坡高的分析方法。该分析方法首先利用有限元得到边坡内部较为精确的应力场,再通过在边坡内部模拟类似于链式反应过程中粒子产生和运动规律,在此基础上完成临界滑动面的搜索。主要结论如下：（1）提出了一种基于数值应力场的边坡临界滑动面的搜索方法,该方法可在不对边坡滑动面形状和位置进行干预的情况下完成潜在破坏路径的搜索。（2）通过对算法中区域与边界、激发源、产物扩散路径、路径权值4方面要素进行合理控制,可使算法在具有较高精度的同时又能保证较好的分析效率。（3）算法能较为方便地考虑真实应力条件下地层强度各向异性对边坡稳定性的影响,并能对临界坡高进行很好的分析。（4）通过具体算例对本文算法的计算结果进行验证,将所得结果与PSO和Monte Carlo两种方法得到结果进行对比,对本文方法的可靠性进行了验证,取得了较好的效果。     

Regional policy in Poland: A search for equity

Polish regional policy and planning has long traditions and post-war socialist policies demonstrate important continuities with the 1930s. Regional policy since 1945 has progressed from sets of individual decisions on reconstruction through more coordinated policies for uniform development, for rational location and for activation of backward regions. Lack of adequate coordination and rigorous accounting, though, often meant excessive concentration of development in existing industrial areas and key urban centres. In the 1960s fashionable growthpole concepts were applied to medium-sized city development without maintaining adequate balance between continued growth in larger cities and new smaller-town development. Reform, long overdue, is required to implement the national spatial plan for the 1990s.     

High-gradient magnetic separation: A search for a matrix material

The magnetic properties and abrasion resistance of selected low-carbon steels were investigated with respect to their suitability as induction matrix materials. Low-remanent ferromagnetic steels and a paramagnetic steel were used in magnetic separation tests with siderite and hematite ores. It was found that recovery and grade for all ferromagnetic materials were equivalent, while recovery for paramagnetic steel was lower, and increased with increasing magnetic induction. However, all investigated steels are less susceptible to hold highly coercive tramp iron which usually causes matrix clogging. Likewise, all selected stainless steels are more abrasion resistant than currently employed matrix materials.