带自由液面有限长圆柱绕流数值模拟

[目的]为了探究自由液面及自由端对典型钝体绕流问题的影响,对带自由液面的有限长圆柱绕流进行研究。[方法]基于延时分离涡模拟（DDES）技术和分段线性界面重构（PLIC）方法,利用自主开发的naoe-FOAM-SJTU求解器开展数值模拟。[结果]结果显示,自由液面和自由端的存在增大了局部位置的升、阻力,推迟了圆柱表面流动分离的发生;相较于深吃水位置,自由液面附近流向的速度“恢复”延缓,横向的速度呈向外运动的趋势;自由液面的变形产生了大量细碎的漩涡,自由端的卷拧状漩涡在一定程度上抑制了卡门涡街的发展。[结论]研究表明,目前采用的数值方法能够准确捕捉复杂流场,同时,自由液面和自由端的存在将显著改变流场沿吃水方向的分布。     

轨道交通AFC系统票卡管理分析

在分析轨道交通票卡应用特点的基础上,把票卡分为回收类票卡和非回收类票卡,研究票卡库存的三级管理流程,详细分析清结算中心、线路中心和车站票卡库存的工作流程.提出回收类车票库存的宽松管理和严格管理,分析这两种方式的特点,并对票卡严格管理方案进行详细分析设计.     

基于层次分析法的船体舭部分段划分方案评价及优化

基于层次分析法梳理船体舭部分段划分的影响因素,构建方案评价分析模型,计算各评价指标的权重,实现量化的方案评价,针对优选方案在总段搭载吊装过程中权重得分较低,应用TSV吊装软件,分析并提出相应解决措施。     

Two Bandwidth Packing Algorithms for the Centralized Wireless Network and Their Average-case Analysis

This paper presents a detail analysis of two bandwidth packing algorithms, used for processing connection requests in the centralized wireless network. Each call comes with a specific bandwidth request. A request can be satisfied only if there is sufficient bandwidth available during resource scheduling and allocation. Unsatisfied requests were held in a queue. The metric of bandwidth utilization ratio was used to quantify the performance of our algorithms. By theoretical analysis, our algorithms can improve the average bandwidth usage ratio significantly, about 8%~10% without adding much computation complexity. Moreover, our algorithms outperform next fit with fragmentation (NFF) algorithm when the bandwidth resource is scarce. In this paper, the contributions follows: Introducing bandwidth packing problem into wireless network; Proposing two new bandwidth packing algorithms for wireless network where the complicate scheduling algorithms are prohibited; Studying the average performance of our algorithms mathematically, which agree well with the simulation results.     

Development of an Autonomous Flight Control System for Small Size Unmanned Helicopter Based on Dynamical Model

It is devoted to the development of an autonomous flight control system for small size unmanned helicopter based on dynamical model. At first, the mathematical model of a small size helicopter is described. After that simple but effective MTCV control algorithm was proposed. The whole flight control algorithm is composed of two parts: orientation controller based on the model for rotation dynamics and a robust position controller for a double integrator. The MTCV block is also used to achieve translation velocity control. To demonstrate the performance of the presented algorithm, simulation results and results achieved in real flight experiments were presented.     

Wind Generator Stabilization with Doubly-Fed Asynchronous Machine

This paper investigates the function of doubly-fed asynchronous machine(DASM)with emphasis placed on its ability to the stabilization of the power system including wind generators.P(active power)and Q(reactive power)compensation from DASM can be regulated independently through secondary-excitation controlling.Simulation results by power system computer aided design(PSCAD)show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures.Comparison studies have also been performed between wind turbine pitch control and proposed method.     

海洋工程平台项目物资追溯管理的批次管理方法

基于海洋工程平台项目特点,研究物资分类、物资编码和物资批次编码等关键技术,引入批次管理方法。按批次阶段形成亚批次清单（Bill of Lots,BOL）,建立物资追溯管理模型,为海洋工程平台项目实现产品全生命周期内的物资追溯管理提供理论依据。     

基于LSTM模型的船舶材料成本滚动预测

船舶建造周期长、材料成本占比大,易受大宗商品价格指数和汇率等多个因素的影响,造成实际完工成本与报价估算存在较大误差的情况。采用灰色关联分析（Grey Correlation Analysis,GCA）方法识别材料成本的影响因素,基于长短期记忆网络（Long Short-Term Memory,LSTM）模型构建船舶材料成本滚动预测模型,并使用某造船企业53艘64 000 t散货船63个月的材料成本数据和对应的影响因素数据进行试验分析。结果表明,预测数据与实际数据误差在可接受范围内,可证明所选择方法和构建模型的有效性。研究结果对船舶建造过程的成本实时预测和控制具有现实意义。     

二赛线GTM沥青混合料设计

结合内蒙古自治区二连浩特-赛汉塔拉的工程实例,介绍了GTM混合料设计方法的特点,以及根据当地的气候、交通状况确定工程级配范围和室内采用GTM完成混合料的设计及技术性能的检验。     

论PLC在桥门式起重机改造中的应用

为解决桥门式起重机所频发的电气故障,将PLC应用于起重机电控系统中。介绍了PLC(可编程控制器)的性能特点和桥门式起重机电控系统的工作原理,介绍了用PLC控制器实现限位保护、综合保护、过流保护的设计技巧。