A hopfield neural network algorithm for automatic name placement for point feature

This paper presents a method of adding label to the map especially for the point feature. This method overcomes the shortcoming of traditional methods, e.g.Conflict-Backtracking method. Its kernel algorithm use the hopfield neural network to find the best label position for point feature. The experimental resuits proves that this algorithm has good permanence and high speed.     

Optimal locations for flow and velocity sensors along a river channel

ABSTRACT

A novel methodology for the optimal placement of sensors in watercourses is presented. The methodology aimed at finding the optimal locations for the placement of sensors to maximize the amount of information to monitor flow and velocity in watercourses. The methodology is based on the maximization of the Gram determinant of the sensor responses at each possible location or a combination of locations. Two illustrative examples are presented wherein locations for one- and two-sensor cases for the velocity and flow monitoring of the Venero Claro River Basin, Spain, are selected. The kinematic wave method was used to evaluate the sensor response at every possible location. The results confirm the suitability of this methodology for finding the optimal locations for sensors to monitor flow or velocity in watercourses.     

How reliable are growth strata in interpreting short-term (10 s to 100 s ka) growth structures kinematics?

High-frequency stratigraphic cycles (10 s to 100 s ka) often show, at a specific location, an alternation of ‘dynamic’ (proximal-energetic), and ‘non-dynamic’ (distal-pelagic) processes with time. When sedimentation is syn-deformation, these processes tend respectively to fill-up tectonically-induced topography or to drape it. As a consequence, growth strata are alternatively thickened and isopach across the growth structure. High-resolution kinematic studies of growth structures (folds and faults), which assume that sedimentation always fills up topographies (‘fill-to-the-top’ model), may therefore mistake sedimentary cyclicity for tectonic cyclicity. We address this problem with one example of growth anticline in the Spanish Pyrenees, and we discuss the fill-to-the-top model. To cite this article: S. Castelltort et al., C. R. Geoscience 336 (2004).     

Visibility Analysis In Vision Metrology Network Design

The aim of this paper is to present a method whereby accuracy enhancement of an existing photogrammetric network is achieved through the automatic selection of additional camera stations. The determination of the positions of these 'accuracy fulfilment' camera stations is based upon what has been termed 'visibility uncertainty prediction modelling' of visibility constraints derived from the existing network geometry. Following a review of vision constraints in network design, the concepts of visibility uncertainty prediction and visibility uncertainty spheres are introduced. These provide a mechanism to predict the visibility of current object target points for the new accuracy fulfilment images. This in turn aids in network design improvement. The visibility uncertainty modelling is then illustrated for two close range photogrammetric network configurations, for which the test results demonstrate that the proposed model can reliably predict target visibility with an overall certainty of 75%.     

长对角线法实现GIS中矢量地图面状地物汉字注记的自动配置

从图形学角度探讨了面状要素自动注记的问题，认为对于GIS矢量地图中大量的复杂面状图形可以通过简化后构建其简单多边形，进而获取简单多边形内的最长对角线作为注记配置的基准线，提出了一种简单快速的地图面状地物汉字注记自动配置的新算法。     

海上水下砼灌注施工技术

结合工程实际，介绍海上水下砼灌注中设备的选用与布置、砼灌注等工艺，并分析对比了翻板阀门水下砼灌注的可靠性。     

城市街道注记离散化定位的自动推理方法

在线状要素注记配置规则的基础上，分析了城市街道注记自动配置规则，研究了从图面注记到空间目标名称属性的自动转换方法。结合Arc／Info平台的特点，给出了城市街道注记离散化定位的自动推理策略和计算方法，在Arc／Info平台上编程实现了该算法。     

Seismic Response of Adjacent Buildings Connected with Friction Dampers

The effectiveness of passive energy dissipation systems to improve seismic performance of connected buildings is now well established through extensive analytical and experimental investigations. However, the performance of buildings connected with friction dampers has not been looked into. In this paper, the investigation is carried out to study the structural responses of two adjacent buildings connected with friction dampers under various earthquake excitations. A formulation of the equations of motion for the two adjacent multi degree of freedom (MDOF) buildings connected with friction dampers is presented. The numerical study is carried out in two parts, namely (i) two adjacent MDOF buildings connected with friction dampers having same slip force in all the dampers and (ii) two adjacent MDOF buildings connected with friction dampers having different slip forces in the dampers. The effectiveness of the dampers in terms of the reduction of structural responses, namely, displacement, acceleration and shear forces of connected adjacent buildings is investigated. A parametric study is also conducted to investigate the optimum slip force of the dampers. In addition, the optimal placement of the dampers, rather than providing the dampers at all the floor levels is also studied to minimize the cost of the dampers. Results show that using friction dampers to connect the adjacent buildings of different fundamental frequencies can effectively reduce earthquake-induced responses of either building if slip force of the dampers is appropriately selected. Also, it is not necessary to connect the two adjacent buildings at all floors but lesser dampers at appropriate locations can significantly reduce the earthquake response of the combined system. Further, it is also observed that the reduction in the responses when the two MDOF buildings connected with 50% of the total dampers is almost as much as when they are connected at all the floors, thereby reducing the cost of the dampers significantly.     

Optimal placement of DVFC controllers on buildings subjected to earthquake loading

The dynamic responses of tall civil structures due to earthquakes are very important to the civil engineer. These dynamic responses can produce situations that can range from uncomfortable to unsafe for the building occupants. In recent years classical control theory has been used in civil engineering to reduce the dynamic responses of tall civil structures. Most optimal control algorithms for civil structures involve full state feedback control which requires good estimates of the velocity and displacements throughout the structure. However, there are several important advantages of output feedback control: it takes less computational effort and it has the robustness of passive systems. In this paper, optimal control algorithms are formulated for the optimization of feedback gains and controller placement for building structures. The fundamental basis for these algorithms is the calculation of the gradient of the performance function with respect to the gain matrix. The effectiveness of the algorithm is demonstrated for deterministic earthquake loads in the time domain. Copyright © 1999 John Wiley & Sons, Ltd.     

Non-monotonic optimal damper placement via steepest direction search

An efficient and systematic procedure is proposed for finding the optimal damper positioning to minimize the dynamic compliance of a 3-D shear building model. The dynamic compliance is expressed in terms of the transfer function amplitudes of the local interstorey drifts evaluated at the undamped fundamental natural frequency. The dynamic compliance is minimized subject to a constraint on the sum of the damping coefficients of added dampers. Optimality criteria are derived and the optimal damper positioning is determined via an original steepest direction search algorithm. This algorithm enables one to find an optimal damper positioning sequentially for gradually increasing damper capacity levels. A non-monotonic design path with respect to the total damper capacity level often appears in the application of this algorithm. A new augmented algorithm via parameter switching is devised to find this non-monotonic design path. Copyright © 1999 John Wiley & Sons, Ltd.