重力式码头后方构筑物周边地面沉降过大缺陷防治

重力式码头后方构筑物周边地面沉降过大,将影响码头的正常使用。结合工程实践,对出现该问题的原因进行分析,并提出预防措施。     

一种多功能抑尘车智能化控制系统的设计

传统抑尘车由于各部件控制系统相对独立,无法实现集成式监控与操作,从而给使用者带来一定的不便。如何将诸多系统一一融合汇总控制成为解决此问题的关键,本文以公司开发的集成式控制的抑尘车为例介绍了一种创新型智能化控制多功能抑尘车控制系统的设计。     

塑料排水带堆载法在填海造陆复杂地基处理中的试验研究

针对填海造陆形成的复杂地基的地质特点,采用分区处理,改进插板方式等多种方法联合摸清薄弱地带范围的处理方案;通过对塑料排水带堆载法加固后地基的沉降变形和孔隙水压力的测试,研究了地基沉降随时间的变化规律和孔隙水压力的时空分布规律,对比分析了加固前后土体物理力学性质的变化;处理后的地基经充分排水固结,土体物理力学指标有了明显的改善,结果表明采用的处理方案及塑料排水带堆载法处理填海造陆形成的复杂地基是合适的。     

An Object-Based Fast Motion Estimation Algorithm in MPEG-4

Introduction The MPEG has successfully developed theMPEG-4 standard[1]to address a wide range ofmultimedia data compression applications. As oneof the major parts of MPEG-4 standard, MPEG-4video aims at providing standardized core technolo-gies allowing efficient storage, transmission andmanipulation of video data in multimedia environ-ments[2]. Compared with its predecessor, MPEG-4 em-ploys many new compression techniques[3]. One ofthe main new features of MPEG-4 is its ability tore…     

电动土工合成材料及其应用

介绍了近年来国外开发的一种新型土工合成材料——电动土工合成材料;介绍了电动土工合成材料的结构及其性能特点,指出了电动土工合成材料给传统电渗加固法带来的便利和革新,并对电动土工合成材料的工程应用进行了介绍和讨论。     

Automatic generation of the non-holonomic equations of motion for vehicle stability analysis

The mathematical analysis of vehicle stability has been utilised as an important tool in the design, development, and evaluation of vehicle architectures and stability controls. This paper presents a novel method for automatic generation of the linearised equations of motion for mechanical systems that is well suited to vehicle stability analysis. Unlike conventional methods for generating linearised equations of motion in standard linear second order form, the proposed method allows for the analysis of systems with non-holonomic constraints. In the proposed method, the algebraic constraint equations are eliminated after linearisation and reduction to first order. The described method has been successfully applied to an assortment of classic dynamic problems of varying complexity including the classic rolling coin, the planar truck–trailer, and the bicycle, as well as in more recent problems such as a rotor–stator and a benchmark road vehicle with suspension. This method has also been applied in the design and analysis of a novel three-wheeled narrow tilting vehicle with zero roll-stiffness. An application for determining passively stable configurations using the proposed method together with a genetic search algorithm is detailed. The proposed method and software implementation has been shown to be robust and provides invaluable conceptual insight into the stability of vehicles and mechanical systems.     

CFG复合地基在高路堤软基处理工程中的应用

桥头深厚软基经CFG复合地基处理后,能满足工后沉降的控制要求,对高填方桥头路基尤其有效。CFG复合地基的施工实践表明:振动沉管法施工CFG桩的挤土效应明显,影响范围可达2.5m。地基处理前后原位测试结果和施工期地表沉降与水平位移的观测结果表明:CFG复合地基对软黏土地基的加固起到了效果,地基土强度明显增强,施工期加载快但地基沉降速率小,保证路基稳定性的同时缩短了工期。     

Efficient estimation of extreme non-linear roll motions using the first-order reliability method (FORM)

In on-board decision support systems, efficient procedures are needed for real-time estimation of the maximum ship responses to be expected within the next few hours, given online information on the sea state and user-defined ranges of possible headings and speeds. For linear responses, standard frequency domain methods can be applied. For non-linear responses, as exhibited by the roll motion, standard methods such as direct time domain simulations are not feasible due to the required computational time. However, the statistical distribution of non-linear ship responses can be estimated very accurately using the first-order reliability method (FORM), which is well known from structural reliability problems. To illustrate the proposed procedure, the roll motion was modelled by a simplified non-linear procedure taking into account non-linear hydrodynamic damping, time-varying restoring and wave excitation moments, and the heave acceleration. Resonance excitation, parametric roll, and forced roll were all included in the model, albeit with some simplifications. The result is the mean out-crossing rate of the roll angle together with the most probable wave scenarios (critical wave episodes), leading to user-specified specific maximum roll angles. The procedure is computationally very effective and can thus be applied to real-time determination of ship-specific combinations of heading and speed to be avoided in the actual sea state.     

Robust gain-scheduling automatic steering control of unmanned ground vehicles under velocity-varying motion

Owing to the fact that unmanned ground vehicles have the features of time-varying, parametric uncertainties and external disturbances, this paper mainly studies robust automatic steering control of unmanned ground vehicles. Firstly, a linear parameter varying lateral model for unmanned ground vehicle is constructed, in which the longitudinal velocity is represented by a polytope with finite vertices. Secondly, a robust gain scheduling automatic steering control scheme based on the linear matrix inequality technique is proposed to deal with the characteristics of time-varying and external disturbances. Finally, Simulation results based on Adams–Matlab joint platform using a nonlinear full vehicle model have demonstrated that the proposed control approach can simultaneously ensure the control accuracy and strong robustness of system.