Understanding Perturbation on the Simplex: A Simple Method to Better Visualize and Interpret Compositional Data in Ternary Diagrams

Perturbation is an operation defined on the simplex and can be used for centering compositional data in a ternary diagram, applying objective criteria. Because a straight line in the original diagram is still astraight line in the perturbed diagram, gridlines or compositional fields defined by straight lines can easily be included in the operation. Simultaneous perturbation of data, gridlines, and/or compositional fields is shown to improve both visualization and graphical interpretation of compositions in ternary diagrams. This is illustrated by some examples using simulated as well as real data.     

To afforest the desert with the technology of peat composed of rotten mosses and the sustainable development of the oases

Only by providing the good conditions for the growth of plants can a favorable ecologicalenvironment on which human beings rely for existence be created. The upside-down-T dou-ble-layer water-conserving afforestation way is developed according to the situation of the short-age of water resources, low soil fertility and vast land in the arid areas. The characteristics of theafforestation way are to change the microenvironment in the root area of the plants, provide thefavorable conditions for the growth of plants, and reduce the necessary conditions for the growth ofplants in large areas in the arid regions. Meanwhile, the size of its water-conserving layer can bechanged according to the size of the planted trees. The different ways of the bottom wa-ter-conserving layer can be used according to the requirements. The afforestation way is suitablefor planting trees on a small scale and also for afforesting on a large scale under the adverse cir-cumstances in the arid areas, and has been effectively used in the afforestation in the hinterland ofTaklamakan Desert and the southern marginal zone of Gurbantonggut Desert. The prospects ofthe afforestation way are broad in afforestation and desertification control in the desert regions.     

Optimal placement of dampers and actuators based on stochastic approach

A general method is developed for optimal application of dampers and actuators by installing them at optimal location on seismic-resistant structures. The study includes development of a statistical criterion, formulation of a general optimization problem and establishment of a solution procedure. Numerical analysis of the seismic response in time-history of controlled structures is used to verify the proposed method for optimal device application and to demonstrate the effectiveness of seismic response control with optimal device location. This study shows that the proposed method for the optimal device application is simple and general, and that the optimally applied dampers and actuators are very efficient for seismic response reduction.     

结构振动控制的半主动磁流变质量驱动器(MR-AMD)

本文首先提出了一种新型的半主动磁流变质量驱动器（MR－AMD），该装置用磁流变驱动器替代AMD的液压驱动系统；其次采用所提出的半主动控制算法仿真分析了MR－AMD用于结构振动控制的有效性；第三，比较了半主动质量驱动器（MR－AMD）、调谐质量阻尼器（TMD）及主动质量驱动器（AMD）对同一模型结构的控制效果。分析结果表明，MR－AMD作为一种半主动质量驱动器有效地降低了结构的反应，其控制效果虽然不如具有相同质量块参数的AMD但却优于TMD，且同AMD一样具有较宽的有效频带范围。     

海洋平台结构振动的AMD主动控制参数优化分析

本文针对海洋平台结构的冰激振动和地震反应控制问题，提出了采用AMD主动控制的控制策略，结合JZ20－2MUQ平台结构进行了AMD控制系统的硬参数和软参数的优化分析，并就相应于最优参数下的AMD控制海洋平台结构冰激振动和地震反应的几种代表性工况进行了时程分析，得到了一些定性和定量的结论，为实际工程的控制设计提供了基础。本文提出的AMD主动控制方法对类似的海洋平台结构的控制问题也有参考价值。     

新疆数字地震前兆台网的数据传输功能分析

为了进一步提高地震前兆数据的传输效率和准确性 ,实现前兆数据采集和管理的自动化 ,对新疆地震局数字化地震前兆台网中心的功能、数据采集原理、数据传输特征进行了分析 ,认为数字化观测技术为地震前兆数据的采集、传输提供了一种高效、可靠的手段     

Seismic structural control using semi-active tuned mass dampers

This paper focuses on how to determine the instantaneous damping of the semi-active tuned mass damper (SATMD) with continuously variable damping. An off-and-towards-equilibrium (OTE) algorithm is employed to examine the control performance of the structure/SATMD system by considering the damping as an assumptive control action. The damping modification of the SATMD is carried out according to the proposed OTE algorithm, which is formulated based on analysis of the structural movement under external excitations, and the measured responses of the structure at every time instant. As examples two numerical simulations of a five-storey and a ten-storey shear structures with a SATMD on the roof are conducted. The effectiveness on vibration reduction of MDOF systems subjected to seismic excitations is discussed. Analysis results show that the behavior of the structure with a SATMD is significantly improved and the feasibility of applying the OTE algorithm to the structural control design of SATMD is also verified.     

Phénomènes karstiques fossiles et actuels au sein des formations métamorphiques silico-alumineuses de la nappe pan-africaine de Yaoundé (Sud-Cameroun)Fossil and present-time karstic phenomena in silico-aluminous metamorphic formations of the Pan-African nappe of Yaoundé (South-Cameroon)

Numerous karstic features have been recognised in the non-carbonaceous micaschists and gneisses of the Yaoundé Pan-African nappe, south of Cameroon. It is shown that their formation was controlled by the structural features of the rocks. The wells and the pipes in the bedrock outcrops point out a current karstification process, resulting from the plagioclase dissolution by the acid rain waters. Hill wall alveoli and caves, of pre-Miocene age, are exhumed features that were done by dissolution in the aquiferous underground. To cite this article: J.-P. Vicat et al., C. R. Geoscience 334 (2002) 545–550.     

空间数据库数据约束系统及其实现

空间数据库模型是构造地理信息系统的关键，如何在空间数据库中定义和实现空间实体间的约束关系直接影响到空间数据的完整性和一致性，是实现通用空间数据库约束系统的关键技术。该文讨论了传统GIS空间数据约束关系实现方法的局限性，提出了一个可扩展的空间数据约束描述和数据更新规则系统，并实现了系统原型。这一可扩展的约束系统将有利于解决GIS的多用户同步操作机制及分布式事务处理的实现问题。     

智能交通系统中的公交车辆指挥调度体系结构

该文阐述公交智能指挥调度系统总体框架，结合智能交通系统ITS(Intelligent Transport Systems)对公交智能化调度的逻辑结构和物理结构要求，分析公交车辆智能化调度系统结构体系及其模型化，探讨智能调度策略和调度机理。根据该系统总体设计框架构思，了解系统各功能间的相互关系，优化公交车辆运营管理模式，以改善现有公交系统的管理水平以及运营效率，为公交指挥调度系统的完善、提高提供可靠技术基础。