沥青混凝土摊铺机电气控制系统的改造

针对沥青混凝土摊铺机单片机数字控制系统的不足，结合可编程控制器完善的功能、特点及良好的接口性能，对摊铺机原控制系统进行了改造，提高了摊铺机电气自动控制系统的工作可靠性，简化了电控系统外围驱动电路。     

Onboard tuning of vessel seakeeping model parameters and sea state characteristics

It is essential for a safe and cost-efficient marine operation to improve the knowledge about the real-time onboard vessel conditions. This paper proposes a novel algorithm for simultaneous tuning of important vessel seakeeping model parameters and sea state characteristics based on onboard vessel motion measurements and available wave data. The proposed algorithm is fundamentally based on the unscented transformation and inspired by the scaled unscented Kalman filter, which is very computationally efficient for large dimensional and nonlinear problems. The algorithm is demonstrated by case studies based on numerical simulations, considering realistic sensor noises and wave data uncertainties. Both long-crested and short-crested wave conditions are considered in the case studies. The system state of the proposed tuning framework consists of a vessel state vector and a sea state vector. The tuning results reasonably approach the true values of the considered uncertain vessel parameters and sea state characteristics, with reduced uncertainties. The quantification of the system state uncertainties helps to close a critical gap towards achieving reliability-based marine operations.     

电厂煤取样装置的技术改造

取样装置是浙江浙能兰溪发电有限责任公司的输煤皮带设备，该公司技术人员通过对取样装置频繁发生堵煤而无法正常投运的原因进行分析，提出合理的各机构改进方案，并对其实施技术改造，取得了较满意的效果。     

A framework for short-term traffic flow forecasting using the combination of wavelet transformation and artificial neural networks

The main objective of this paper is to develop a framework for short-term traffic flow forecasting models with high accuracy. Due to flow oscillations, the real-time information presented to the drivers through variable message signs, etc., may not be valid by the time the driver reaches the location. On the other hand, not all compartments of the flow signal are of same importance in determining its future state. A model is developed to predict the value of traffic flow in near future (next 5–35?minutes) based on the combination of wavelet transformation and artificial neural networks. This model is called the hybrid WT-ANN. Wavelet transformation is set to denoise the flow signal, i.e., filtering the unimportant fluctuations of the flow signal. Unimportant fluctuations are those that have little or no effect on the future condition of the signal. The neural network is set and trained to use previous data for predicting future flow. To implement the system, traffic data of US-101 were used from Next Generation Simulation (NGSIM). Results show that removing the noises has improved the accuracy of the prediction to a great extent. The model was used to predict the flow in three different locations on the same highway and a different highway in a different country. The model rendered highly reliable predictions. The proposed model predicts the flow of next 5?min on the same location with 2.5% Mean Absolute Percentage Error (MAPE) and of next 35?min with less than 12% MAPE. It predicts the flow on downstream locations for next 5?min with less than 8% MAPE and for the different highway with 2.3% MAPE.     

手持GPS的坐标转换参数

描述了坐标系统的概念及不同坐标系统的转换模型,以GARM IN手持GPS为例,说明各转换参数的含义、求解方法并给出1954年北京坐标系和1980西安坐标系下转换参数的经验值,对手持GPS进行误差分析及转换参数的适用范围。     

两层介质中运动垂直时谐偶极子产生的电磁场

基于时谐电磁场的麦克斯韦方程,利用在两层介质情况下的矢量磁位边值条件,然后经过狭义相对论的洛仑兹变换,求解出匀速运动的垂直时谐电偶极子在介质中产生的电磁场的表达式,文章最后以深海中低速运动的极低频垂直时谐偶极子为例,运用基于汉克尔变换式的FFT变换算法对所得到的磁场解析式进行了数值计算,并且通过分析计算结果得出有价值的结论.     

H.264视频技术在山西省高速公路监控系统中的应用

山西省在2003年已实现视频监控的模拟和MPEG-2混合的视频联网,随着路网的扩大,图像的增加,目前这种视频组网方式存在片区中心和省中心扩容较难,通信资源占用过大的问题,由于H.264技术已完善成熟,为了解决当前所面临的问题,决定对现有系统进行H.264图像传输改造,主要对片区输出图像在输出端视频分配后进行H.264编...     

齐次线性方程组基础解系的求法

本文给出了求齐次线挂方程组基础解系的一种简单求法,并结合实际案例,给出了用矩阵的初等变换直接求齐次线性方程组基础解系的详细过程。     

从实践看深化设计对船厂转模的推动

针对传统造船模式下,造船生产设计不到位、深度不够的问题,结合船厂对生产设计的探索,通过对设计软件的更新换代及设计编码的继承创新,使深化生产设计取得了阶段性的成果,推动了设计、生产、管理各方面的改革,推进了转换造船模式的进程。