Oscillating Body Design for A 3-DOF Wave Energy Converter

Ocean wave energy converters(WECs) are obtaining more and more attentions in the world. So far, many types of converters have been invented. Oscillating body systems are a major class of WECs, which typically have one degree of freedom(DOF), and the power absorption efficiency is not quite satisfactory. In this paper, a 3-DOF WEC is proposed and a simplified frequency-domain dynamic model of the WEC depending on the linear potential theory is conducted. The performances of three geometries of the oscillating body including the cone, the cylinder and the hemisphere have been compared, and the results show that the hemisphere is more suitable for the 3-DOF WEC.Subsequently, the relationship among the parameters of the hemisphere is established based on the equal natural frequencies of the heave and pitch(or roll) motions, and the results show that lowering the center of gravity leads to the better power absorption in the pitch(or roll) motion. In the end, the power matrixes of different sizes of the hemispheres under different irregular waves are obtained, which can give a size design reference for engineers.

DESIGN AND IMPLEMENTATION OF A 3-DIMENSIONAL COMPUTER AIDED GARMENT DESIGN SYSTEM

A 3-Dimensional computer aided garment design (CAGD) system has been developed andimplemented on a high-performance workstation. We studied various approaches to the func-tional modelling of garment designs for the system. According to the characteristic data of a hu-man body, the models of human body and the garment are displayed on the screen, then we canmodify the garment with various styles and different sizes. The system can transform the 3-Dgarment to the 2-D pieces. The system has improved design efficiency. Various potential alterna-tives and improvement of the system have also been studied and explored.

A 3-D RECONSTRUCTION METHOD BASED ON THE CONSTRAINT OF EPIPOLAR GEOMETRY

This paper combines the least-square method and iteration method to get the fundamental matrix and develops a new evaluation function based on the epipolar geometry. During the iteration, with the evaluation function as a measurment, the points which bring larger noise are deleted, and the points with smaller noise are retained, thus the precision of our method is increased. The experiment results indicate the new method is precise in calculation, stable in performance and resistant to noise.

3-D MODELLING OF COMPUTER AIDED GARMENT DESIGN

This paper describes a method of the computer aided garment design,and discusses 3-D humanbody,wire frame modelling,approaches of expressing and a shading model of the 3-D garment.

Constrained geometry analysis to resolve 3-D deformations from three ground-based radars

When multiple ground-based radars(GB-rads)are utilized together to resolve three-dimensional(3-D)deformations,the resolving accuracy is related with the measurement geometry constructed by these radars.This paper focuses on constrained geometry analysis to resolve 3-D deformations from three GB-rads.The geometric dilution of precision(GDOP)is utilized to evaluate 3-D deformation accuracy of a single target,and its theoretical equation is derived by building a simplified 3-D coordinate system.Then for a 3-D scene,its optimal accuracy problem is converted into determining the minimum value of an objective function with a boundary constraint.The genetic algorithm is utilized to solve this constrained optimization problem.Numerical simulations are made to validate the correctness of the theoretical analysis results.

Predication of 3-D Viscous Flowfield of a Centrifugal Impeller

A three-dimensional viscous code has been developed to solve Reynolds-averaged Navier-Stokes equations. The governing equations in finite volume form are solved by two-step Runge-Kutta scheme with implicit residual smoothing. The eddy viscous is obtained using the Baldwin-Lomax model. A prediction of the 3-D turbulent flow and the performance in the “all-over controlled vortex distribution” centrifugal impeller with a vaneless diffuser has been made for the compressor at design and off-design condition. The predicted effi-ciency is a little higher than the experiment data. These results suggest that the present calculation code is able to determine the flow development in the impeller and also the turbulence model in the centrifugal im-peller should be improved.

Magnetic field of mathematical modeling and simulation of 3D magnetic pole array spherical actuator

In this paper a new spherical actuator is designed and its advantages are compared to an existing spherical actuator, which function is limited by several design bottlenecks. First the output torque is too small. Second, the attitude is difficult to be accurately detected. The new three-dimen- sional magnetic pole array can solve these major problems. The new actuator features an outer rotor with multiple permanent magnet （PM） poles. Using an analytical solution and the finite element so- lution simulation, the feasibility of the approach is verified. A prototype was developed, tested, and experiments were conducted to obtain the practical value of the magnetic flux density.

Depth estimation system suitable for hardware design

Depth estimation is an active research area with the developing of stereo vision in recent years. It is one of the key technologies to resolve the large data of stereo vision communication. Now depth estimation still has some problems, such as occlusion, fuzzy edge, real-time processing, etc. Many algorithms have been proposed base on software, however the performance of the computer configurations limits the software processing speed. The other resolution is hardware design and the great developments of the digital signal processor （DSP）, and application specific integrated circuit （ASIC） and field programmable gate array （FPGA） provide the opportunity of flexible applications. In this work, by analyzing the procedures of depth estimation, the proper algorithms which can be used in hardware design to execute real-time depth estimation are proposed. The different methods of calibration, matching and post-processing are analyzed based on the hardware design requirements. At last some tests for the algorithm have been analyzed. The results show that the algorithms proposed for hardware design can provide credited depth map for further view synthesis and are suitable for hardware design.

The Acoustic Performance of 3D Printed Multiple Jet Nozzles with DifferentConfigurations

This work investigated multiple jet nozzles with various geometrical shape,number of exits,and material on reducing noise radiated from jet flows.Nozzles are categorized in two groups with few and many exit numbers,each with various exit shapes,slot and circular,and geometry.Firstly,nozzles are designed and then fabricated by a 3D printer,Form Labs,Form2USA,with polymeric resin.Also,the nozzle with the most noise reduction made of stainless steel.Noise and air thrust were measured at three air pressure gauges,3,5,7 BAR and directions from nozzle apex,30°,90°,135°.Nozzles with slot exit shape made of both plastic and stainless steel revealed the most noise reduction among all nozzles with few exit numbers,nearly 11–14 dB(A)and 11.5–15 dB(A),respectively.On average,slotted nozzle noise reduction was nearly 5–6 dB(A)more than finned nozzle.However,nozzles with more exit numbers,finned and finned-central exit,illustrated much more noise reduction than nozzles with few exit numbers,by almost 16–18 dB(A),they represented similar sound.All tested nozzles and open pipe demonstrated equal air thrust at each pressure gauges.The nozzles with slotted exit shape,either plastic or stainless steel,can provide reasonable noise reduction in comparison to other configuration with few exit numbers.In contrast,nozzles with more exit numbers demonstrated the most noise reduction.

Parallel VLSI design for the fast 3-D DWT core algorithm

By studying the core algorithm of a three-dimensional discrete wavelet transform(3-D DWT)in depth,this paper divides it into three one-dimensional discrete wavelet transforms(1-D DWTs).Based on the implementation of a 3-D DWT software,a parallel architecture design of a very large-scale integration(VLSI)is produced.It needs three dual-port random-access memory(RAM)to store the temporary results and transpose the matrix,then builds up a pipeline model composed of the three 1-D DWTs.In the design,the finite state machine(FSM)is used well to control the flow.Compared with the serial mode,the experimental results of the post synthesized simulation show that the design method is correct and effective.It can increase the processing speed by about 66%,work at 59 MHz,and meet the real-time needs of the video encoder.

三维观测系统属性分析与优化设计

三维观测系统设计及其属性分析研究是地震数据采集的一个重要环节,其中观测系统属性分析中炮检距分布的合理性又是最重要的参数之一。现有的地震数据采集软件也未提供一个定量分析评判的标准。为此本文从炮检距分布合理性的定量化判断及其观测系统参数的最优化设计出发,提出了采用面元内相邻炮检距的变化率大小来判断炮检距分布的均匀性,利用炮检距变化率的方差最小化作为观测系统参数优化选择的目标函数,这在一定程度和部分环节上为观测系统的优化设计提供了新的方法和手段。

基于地球物理目标参数的三维观测系统优化设计

对于陆上三维地震采集的线束状观测系统优化设计,记录仪器的有效利用道数、观测系统总的覆盖次数、排列片的最大炮检距是最为重要的地球物理目标参数。针对这3个目标参数所论证的期望值的偏差最小化,提出了一套三维观测系统优化设计方法,即利用有约束的数学规划求解优化的目标函数,实现三维观测系统参数的最优化设计。应用该设计方法对胜利探区4个实际区块的观测系统参数进行了优化设计和对比分析,结果表明,在窄方位角采集、纵横向覆盖次数均匀分布等方面该方法的效果较好。

基于地震数据处理的三维地震观测系统设计——泌阳凹陷南部陡坡带三维地震观测系统设计实例

为查明泌阳凹陷南部陡坡带内边界大断裂的位置及断裂带的内幕结构,本文针对该区的地震地质条件,从静校正、速度分析、三维DMO和偏移等四项关键处理环节对原始地震数据的要求出发,设计了三维地震观测系统。在权衡各项处理要求和工作效率情况下,确定了每一排列片线数、满覆盖测线长度、面元尺度、纵横向覆盖次数及排列类型。应用结果表明,采用上述观测方法所获得的地震资料质量较原资料有明显的改善,断裂位置成像清晰,目的层及其以上各反射层特征清晰可靠,分辨率和信噪比均有提高,基本达到了预期的效果。

马厂油田高密度三维观测系统设计研究

马厂油田的地下地质构造复杂,以往采集的地震资料无法满足当前勘探开发的需要。针对这一问题,开展了高密度三维采集观测系统设计研究。基于马厂构造的地质构造特点,对观测系统的各类参数进行了分析试验,在此基础上设计了小道距、小炮点距、小接收线距和小激发线距的观测系统,并根据目标区实际地质构造特点,采用可变面元方式进行数据采集。高密度观测系统的特点是物理点密度较大,覆盖次数高,炮检距分布均匀。正演模拟和实际应用表明,采用高密度三维采集观测系统采集的资料,信噪比和分辨率较老资料有显著提高,特别是中、深层资料的信噪比得到了明显改善。

三维VSP观测系统设计研究

三维VSP观测系统设计取决于地面炮数、井下可利用检波器数目、井源距、检波点深度、炮点分布和检波点分布等方面,设计合理的观测系统能够改善井孔附近地层的三维成像效果。通常可以通过覆盖次数和井源距等面元属性参数来衡量三维VSP观测系统设计的合理性。本文研究了井源距和检波点深度、炮点和检波点的分布对纵波和转换波的观测范围、覆盖次数的影响,通过计算与分析,得出以下认识:①检波点深度越小、井源距越大,则观测面积越大;②PS波观测面积小于PP波观测面积;③在检波器个数和炮点分布固定的情况下,适当增加检波点间距有利于覆盖次数均匀;④在炮点呈环形分布或束状分布且炮点间距与炮线间距相当时覆盖次数较为均匀,PP波、PS波覆盖次数的均匀程度基本相当。

斜井三维VSP观测系统设计

三维VSP资料具有高分辨率和高信噪比的特点,十分有利于井旁构造成像和油藏描述。由于海上三维VSP勘探大都在斜井中进行。因此,针对斜井的观测系统设计是否合理至关重要。在斜井三维VSP观测系统设计中,需要解决的主要问题有:①炮点分布中心位置的确定;②炮点缺失对覆盖范围和覆盖次数的影响;③多井炮点和多井检波点的布置等。通过模拟计算分析,对上述问题进行了探讨,得到了一些有益的认识。根据研究结果,制定了某实际斜井的三维VSP观测系统设计方案。

最优性价比的观测系统设计方法研究

三维观测系统优化设计是野外地震采集工作的一个重要环节,影响着后期地震资料采集处理解释的各个工作环节.因此,高质量的观测系统设计是地震勘探工作的关键,然而在无限制的追求高信噪比、高分辨率的地震资料,高难度的野外施工的同时,这往往会带来较大的成本投入.鉴于以上存在的问题,文章着重分析质量最优和成本最优的观测系统设计,通过寻找观测系统参数与采集质量和采集成本的关系,结合二者的优点,提出了最优性价比的观测系统优化设计方法,并通过一个实际工区的试验,体现出该方法的应用效果,为高质量的观测系统设计提供新的思路和方法.

基于目标的三维观测系统设计——以百色盆地北部陡坡带实际应用为例

广西百色盆地地下构造十分复杂,其北部地层高陡,断裂异常发育。以往的勘探,一是受仪器设备和技术条件的制约,观测系统CDP网格过大,排列长度较短;二是没有针对盆地中油气最富集的目标区(北部陡坡带) 进行针对性的观测系统设计,致使地震剖面的波组特征不明显,断点不清晰,构造难以准确落实。为查明百色盆地3条主控断层的产状、性质和展布情况,落实北部陡坡带的盆地边界地层接触关系,针对该区地震地质条件, 进行了基于目标的三维观测系统设计。首先,对以往的三维地震勘探观测系统进行了分析,找出了问题的症结所在;然后,提出了设计思路,并利用弹性波波动方程正演方法对目标区北部陡坡带进行了正演模拟,分析了不同地震地质条件下资料的品质以及满足地质条件的采集参数;最后,针对该区的复杂构造进行了基于目标的三维观测系统设计。在北部陡坡带,利用基于目标的观测系统采集的资料,信噪比得到了较大改善,品质较好,可用于精细构造解释。

铁路客车车顶断面的圆弧型几何设计

本文在现有铁路客车车顶断面几何形状二段弧设计的基础上，根据我国铁道车辆生产的实际情况从理论上探讨了在既定条件下铁路客车车顶断面几何形状的三段弧设计问题，进而给出了可行解的范围和设计步骤，为我国铁路客车设计解决了一个难题。

城区特大型障碍物变观三维观测系统设计及应用——以德阳三维为例

在过德阳城区的地震勘探施工中,采用多种技术相结合的变观设计方法,在城区加密接收线和使用固定排列,城区周边根据"束内调整"和"束间调整"相结合的原则进行炮点布设,并对观测系统进行反复调整和属性分析,设计出适用的变观方案,弥补炮点不足造成的小炮检距缺失。同时采用新设备,压制城区内的部分环境噪声,取得较好的地震采集效果。