Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

A Novel Model for Describing Rail Weld Irregularities and Predicting Wheel-Rail Forces Using a Machine Learning Approach

Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed railways.They can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and deterioration.Few researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry irregularities.However,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric shape.In this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to Shanghai.The vertical dynamic forces in the time and frequency domains were compared under different running speeds.These forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed model.Finally,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is found.The results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the literature.The ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.

Fault Diagnosis of Linear Guide Rails Based on SSTG Combined with CA-DenseNet

Monitoring the status of linear guide rails is essential because they are important components in linear motion mechanical production.Thus,this paper proposes a new method of conducting the fault diagnosis of linear guide rails.First,synchrosqueezing transform(SST)combined with Gaussian high-pass filter,termed as SSTG,is proposed to process vibration signals of linear guide rails and obtain time-frequency images,thus helping realize fault feature visual enhancement.Next,the coordinate attention(CA)mechanism is introduced to promote the DenseNet model and obtain the CA-DenseNet deep learning framework,thus realizing accurate fault classifica-tion.Comparison experiments with other methods reveal that the proposed method has a high classification accuracy of up to 95.0%.The experimental results further demonstrate the effectiveness and robustness of the proposed method for the fault diagnosis of linear guide rails.

A Ventral Diverterless High Offset S-shaped Inlet at Transonic Speeds

An investigation on the ventral diverterless high offset S-shaped inlet is carried out at Mach numbers from 0.600 to 1.534, angles of attack from -4° to 9.4°, and yaw angles from 0° to 8°. Results indicate： （1） a large region of low total pressure exists at the lower part of the inlet exit caused by the counter-rotating vortices in the S-shaped duct; （2） the performances of the inlet at Mach number 1.000 reach almost the highest, so the propulsion system could work efficiently in terms of aerodynamics; （3） the total pressure recovery increases slowly at first and then remains unvaried as the Mach number rises from 0.6 to 1.0, however, it does in an opposite manner in the conventional diverter-equipped S-shaped inlet; （4） the performances of the inlet are generally insensitive to angles of attack from -4° to 9.4° and yaw angles from 0° to 8° at Mach number 0.850, and angles of attack from -2° to 6° and yaw angles from 0° to 5° at Mach number 1.534.

Ruby On Rails在中医药数据共享平台的应用

Ruby on Rails(简称ROR)是一个Web应用程序框架,以其能快速开发而备受敏捷开发实践者的推崇,它包含的重要概念有MVC模式、DSL、习惯约定优于配置、生成器、低重复等.以一个实际课题"中医药数据库共享平台"为例,研究如何应用ROR技术来满足一个实际需求的项目,涉及的技术有MVC模式、RESTful SOA、AJAX、Lighttpd&FCGI等.

基于Rails的RESTful Web Service研究与实现

随着Web服务的快速发展,基于REST(Representational State Transfer)风格的Web Service越来越受到业界的关注。在实现RESTful Web Service的众多框架中,Rails完整实现了MVC并对RESTful Web Service的开发作了极大的封装和简化,使得开发人员用Rails实现RESTful Web Service变得容易。对RESTful Web Service特征和Rails框架结构进行了概述,分析了Rails实现RESTfulWeb Service的原理,在此基础上结合实例给出了基于Rails的RESTful Web Service以及RESTful Web Service客户端的开发步骤和方法,并且利用Ruby进行了实现。

基于Ajax on Rails的WebGIS应用

运用目前两种炙手可热的Web开发技术:AJAX和Ruby on Rails为WebGIS提供一个新的解决方案,AJAX技术作为一种新兴的网络技术比传统页面刷新模式具有更好的性能和友好的用户体验,不过在建立大量的Javascript的代码基础上的,本文通过对AJAX on Rails原理进行分析,运用Ruby on Rails的动态性和敏捷性使AJAX模式带来的程序量大、首页加载时间长的缺陷得到改善,进一步提高程序性能。在实现环节上,在该平台上结合使用Google Maps API,以GXmlHttp在Rails上实现了AJAX的WebGIS关键应用。

Ruby on Rails框架研究与应用

介绍了Rails平台,研究了Ruby on Rails架构拓扑,阐述了Ruby on Rails架构的原理和优势。

基于Rails和jQuery的Web应用程序敏捷开发

随着网络的日益普及,对电子商务和电子政务的需求日趋丰富,越来越多的企业和政府部门都希望将日常管理逐步信息化和网络化。在这种背景下,如何快速构建网页应用程序,以最短的时间,最少的投资,取得最好的效果,成为Web应用开发人员迫切希望解决的问题。本文提出了一种开发方法,用Rails框架快速开发web应用的功能,用jQuery完善Web应用界面,实现web应用程序的快速开发。

基于Ruby on Rails的粮食安全监测预警系统设计与实现

在分析了基于Ruby on Rails开发Web应用程序的优势基础上,设计出了粮食安全监测预警系统,并介绍了系统的总体设计和技术实现.通过系统给出的有效的、简明的预测结果来指导决策,防止粮食生产偏离正常发展轨道或出现危机.

基于Ruby on Rails框架的体育门户网站的研究

基于Ruby语言构建的全新的Web开发框架Ruby on Rails,为Web应用程序开发提供了极其便捷的途径,近年来的迅速兴起成为了Web开发社区的焦点.采用支持敏捷开发的Ruby on Rails框架,研究并设计了一个新型体育门户网站,并重点介绍了网站各模块的主要功能以及实现的关键技术.

一种新兴的Rails开发框架的应用研究

Rails是一个使web应用的开发、部署和维护变得更容易的新兴框架。通过与传统的WEB开发框架的比较,着重挖掘Rails框架的开发优势、核心体系结构及其关键技术,并通过在线购物系统原型(POSS)的具体开发实例,验证了在Ralis框架下开发应用的敏捷性、方便性等卓越的开发效率。同时,针对该框架下不支持中文显示和数据传输效率低等问题,给出了相应的解决方案。这些技术上的改进在一定程度上优化了Rails框架,对于促进该框架的推广和应用具有一定的实际意义。

一种复杂Rails系统架构优化方法

本文将介绍一种Rails系统架构优化方案，将复杂的Rails单一系统拆分成相互协作的多个轻量级应用集群，从根本上解决Rails系统在处理复杂的业务时代码臃肿、开发效率降低、难以维护与部署等问题。

Ruby on Rails与Struts+Hibernate架构之比较分析

Ruby on Rails是一个基于Ruby语言构建的全新Web应用程序架构,为Web应用程序开发提供了一种极其快捷的途径,正在和已经引起业界相当的兴趣.在给出了Ruby on Rails与轻量级J2EE架构Struts+Hibernate关键特性的基础上,从前端控制器、动作和模型,持久性框架三个方面对两种架构进行了比较.

一种在ruby on rails中图片上传与处理的方法

以SNS、BLOG等为代表的web2.0应用中,经常需要上传图片,而且要对图片进行缩放处理,得到缩略图。使用ruby on rails开发框架,通过attachment_Fu插件可以方便地实现所有这些功能。这大大提高了web应用的开发效率,符合用户对web2.0应用持续开发、持续改进、持续创新的要求。

无数据库模型在rails的form_for表单中的应用

rails的Active Model作为模型可以应用于不需要数据库存储数据的场合。经过定制,它可以很好地在form_for表单中工作。

基于Ruby on Rails的WEB开发新技术

新Web开发框架Ruby on Rails的迅速兴起引起了开发社区的关注,它大大提高了开发者开发可信赖的干净的应用程序的效率。本文分析了Web应用与开发领域的发展状况,将Rails的核心观念与传统框架进行对比,探讨其迅速流行与成功的原因及未来的前景。

用rails中的before_action简化身份验证

网站的身份验证代码很多时候都是重复的,并且和功能代码混杂在一起。用before_action则可以简化代码。

基于Rails的辅助教学系统的设计与实现

为大幅度缩短针对新的教学需求的计算机辅助教学系统的开发周期,同时高效的维护系统,研究了当前流行的Ruby On Rails框架技术。基于模型-视图-控制器（model-view-controller,MVC）设计模式进行系统开发,该系统可实现注册登录、作业提交、上机管理、上机测验、发送邮件、信息查询、作业检查、密码提醒等功能。测试结果表明了该软件的实用性。

基于Rails框架的ActiveRecord模块研究与应用

对Rails框架下ActiveRecord模块—一种数据持久层的对象/关系映射技术进行研究了分析。介绍了对象/关系映射技术和ActiveRecord模块同名原型ActiveRecord的基本原理,比较了Java流行框架Hibernate与其间的差别,阐述了Rails框架下ActiveRecord原理和特点。以广告缴费管理子系统为例,展示了ActiveRecord强大的特性。