On the existence of an optimal control of ship automatic steering instruments

The existence of linear quadratic optimal control of ship automatic steering instruments is studied. Firstly, the sufficient conditions for the quadratic integrability of the solutions of linear second order time-variant differential equations are developed. Secondly, the optimal control form of the ship automatic steering instrument is obtained by using the dynamic programming method, which guarantees a minimal ship sway range, during long-distance navigation, by using as little energy as possible. Finally, based on the above mentioned sufficient conditions, the conditions for the realization of optimal control are obtained, which provides a foundation for choosing the weighted coefficients for optimal control in engineering.     

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A Variant Constrained Genetic Algorithm for Solving Conditional Nonlinear Optimal Perturbations简

A variant constrained genetic algorithm （VCGA） for effective tracking of conditional nonlinear optimal perturbations （CNOPs） is presented. Compared with traditional constraint handling methods, the treatment of the constraint condition in VCGA is relatively easy to implement. Moreover, it does not require adjustments to indefinite pararneters. Using a hybrid crossover operator and the newly developed multi-ply mutation operator, VCGA improves the performance of GAs. To demonstrate the capability of VCGA to catch CNOPS in non-smooth cases, a partial differential equation, which has ＂on off＂ switches in its forcing term, is employed as the nonlinear model. To search global CNOPs of the nonlinear model, numerical experiments using VCGA, the traditional gradient descent algorithm based on the adjoint method （ADJ）, and a GA using tournament selection operation and the niching technique （GA-DEB） were performed. The results with various initial reference states showed that, in smooth cases, all three optimization methods are able to catch global CNOPs. Nevertheless, in non-smooth situations, a large proportion of CNOPs captured by the ADJ are local. Compared with ADJ, the performance of GA-DEB shows considerable improvement, but it is far below VCGA. Further, the impacts of population sizes on both VCGA and GA-DEB were investigated. The results were used to estimate the computation time of ~CGA and GA-DEB in obtaining CNOPs. The computational costs for VCGA, GA-DEB and ADJ to catch CNOPs of the nonlinear model are also compared.     

地下流体数字化单井综合观测技术方案的对比实验

根据已有的地下水单井综合观测方案和宁德地震台所具备的实验条件,就若干种不同方案在宁德地震台开展对比观测,并对4种方案的实际观测效果和其它有关优缺点分别给出科学评价。然后根据实验和分析结果,从中选出在科学上合理、技术上可行的最优方案。     

成都地区节能日光温室气象参数设计

应用气侯学基本原理,当地天文参数与气候资料,计算了成都地区节能日光温室采光面最佳倾斜角,顶面覆盖材料承受最大风压,防寒沟深度及温室间适宜距离。     

Optimal decision-making model of spatial sampling for survey of China’s land with remotely sensed data

In the remote sensing survey of the country land, cost and accuracy are a pair of conflicts, for which spatial sampling is a preferable solution with the aim of an optimal balance between economic input and accuracy of results, or in other words, acquirement of higher accuracy at less cost. Counter to drawbacks of previous application models, e.g. lack of comprehensive and quantitativecomparison, the optimal decision-making model of spatial sampling is proposed. This model first acquires the possible accuracy-cost diagrams of multiple schemes through initial spatial exploration, then regresses them and standardizes them into a unified reference frame, and finally produces the relatively optimal sampling scheme by using the discrete decision-making function (built by this paper) and comparing them in combination with the diagrams. According to the test result in the survey of the arable land using remotely sensed data, the Sandwich model, while applied in the survey of the thin-feature and cultivated land areas with aerial photos, can better realize the goal of the best balance between investment and accuracy. With this case and other cases, it is shown that the optimal decision-making model of spatial sampling is a good choice in the survey of the farm areas using remote sensing, with its distinguished benefit of higher precision at less cost or vice versa. In order to extensively apply the model in the surveys of natural resources, including arable farm areas, this paper proposes the prototype of development using the component technology, that could considerably improve the analysis efficiency by insetting program components within the software environment of GIS and RS.     

一个快速海洋三维温盐流分析系统及在亚丁湾临近海域的应用

开发了一个能快速估计三维海洋温盐流场的分析系统.这种系统以海洋数值模式多年积分的气候态结果作为背景场,通过多变量的集合最优插值同化方法利用现场观测和遥感卫星高度计及海表温度观测先对背景场进行偏差订正,以订正的背景场产生当前或瞬时的背景场,结合实时或近期观测通过集合最优插值方法得到三维海洋状态的估计.这种分析系统的优点是...     

Ice concentration assimilation in a regional ice-ocean cou- pled model and its application in sea ice forecasting

A reasonable initial state of ice concentration is essential for accurate short-term forecasts of sea ice using ice-ocean coupled models. In this study, sea ice concentration data are assimilated into an operational ice forecast system based on a com- bined optimal interpolation and nudging scheme. The scheme produces a modeled sea ice concentration at every time step, based on the difference between observational and forecast data and on the ratio of observational error to modeled error. The impact and the effectiveness of data assimilation are investigated. Significant improvements to predictions of sea ice extent were obtained through the assimilation of ice concentration, and minor improvements through the adjustment of the upper ocean properties. The assimilation of ice thickness data did not significantly improve predictions. Forecast experiments show that the forecast accuracy is higher in summer, and that the errors on five-day forecasts occur mainly around the marginal ice zone.     

武威重离子治癌装置高能束线的准直安装

新型粒子加速器对关键元件的准直测量精度要求越来越高,而现有测量仪器受自身技术发展的限制,难以在短时间内显著提高其单站测量精度,由此提出一种基于激光跟踪仪的三维测边网平差的预准直测量方法。通过布设多个测站,将定位点和测站点的坐标均作为未知参数进行平差解算,得到较高精度的定位点坐标。此外,通过比较分析不同测站数目下各定位点的解算精度,得到局部最优测站数。实验结果表明,三维测边网平差解算的定位点精度远高于同等观测条件下三维边角网平差解算的定位点精度。当采用22个测站时,各定位点的空间点位中误差的均值为8.9 μm。根据4个定位点均要获得10 μm以内的定位精度需求,综合考虑定位精度和工作效率两方面因素,判断布设12个测站能达到此要求。所提方法对实际工作中高精度的预准直测量和设备的安装定位具有一定的工程应用价值。     

实时动态最佳路径的实现方法

在现有交通设施下,提出了实时动态路段阻抗的获取及实时动态最佳路径在计算机上的实现方法。