太阳辐照绝对辐射计的精密温度控制系统设计

为了提高太阳辐照绝对辐射计(SIARs)的测量精度,消除温度变化对SIARs测量精度的影响,研究设计了精密温度控制系统,对SIARs进行恒温控制;通过对铂电阻温度传感器自热效应的弱化,提高了温度测量的精度;提出了一种新的复合PID控制算法,该复合控制算法使系统获得良好的动态和稳态性能;使用密闭的高低温箱来模拟星上温度条件对系统进行了实验测试,实验数据表明,系统控制精度在0.1℃以内,可为SIARs工作提供稳定的温度环境。     

基于MAX16802B的水下相机控制系统设计

水下相机对海洋生物科学研究有重要意义,其控制系统的设计关键在于光源控制方案以及电源效率的提高;提出并实现了一种基于低功耗微控制器、高亮LED光源以及LED控制驱动器MAX16802B的水下相机控制系统,详细介绍了系统组成,并给出了基于低功耗策略的硬件和软件优化设计方案;实验结果表明,该设计方案电路结构简单,稳定性好,电源效率达75%以上,能够满足长时间水下拍摄工作;在实际海下测试中,按20分钟的拍摄间隔需求,水下相机可连续工作2个月以上。     

视觉测量中多光学靶点亮度自适应控制

提出了一种面向大视场高精度视觉测量的多红外目标靶点（红外LED）亮度自适应控制方法。以微控制器PIC16F873A和LED驱动芯片MAX6964作为核心器件,设计了可满足大空间范围内靶点亮度控制需求的多目标靶点控制驱动器。为了使LED在近距测量时的调节精度和远近距离测量时的发光亮度都能满足要求,根据MAX6964输出特点设计了PWM信号输出电路,并采用推挽电路驱动LED。实验证明,目标靶点在CCD相机上成像光斑稳定一致。     

NAND Flash内存设备的读写控制设计

针对NAND Flash闪存设备在嵌入式系统中的应用,详细分析了Flash闪存设备的接口设计方法。根据NANDFlash的读写特性,采用Hynix半导体公司的Flash H27U1G8F2B,设计一种闪存数据读写控制方法和驱动流程。该方法能够应用于各种NAND Flash的读写控制,具有良好的程序结构和较高的代码运行效率。     

Retrospective adaptive prefetching for interactive Web GIS applications

A major task of a Web GIS (Geographic Information Systems) system is to transfer map data to client applications over the Internet, which may be too costly. To improve this inefficient process, various solutions are available. Caching the responses of the requests on the client side is the most commonly implemented solution. However, this method may not be adequate by itself. Besides caching the responses, predicting the next possible requests from a client and updating the cache with responses for those requests together provide a remarkable performance improvement. This procedure is called “prefetching” and makes caching mechanisms more effective and efficient. This paper proposes an efficient prefetching algorithm called Retrospective Adaptive Prefetch (RAP), which is constructed over a heuristic method that considers the former actions of a given user. The algorithm reduces the user-perceived response time and improves user navigation efficiency. Additionally, it adjusts the cache size automatically, based on the memory size of the client’s machine. RAP is compared with four other prefetching algorithms. The experiments show that RAP provides better performance enhancements than the other methods.     

Molecular dynamics-based prediction of boundary slip of fluids in nanochannels

Computational modeling and simulation can provide an effective predictive capability for flow properties of the confined fluids in micro/nanoscales. In this paper, considering the boundary slip at the fluid–solid interface, the motion property of fluids confined in parallel-plate nanochannels are investigated to couple the atomistic regime to continuum. The corrected second-order slip boundary condition is used to solve the Navier–Stokes equations for confined fluids. Molecular dynamics simulations for Poiseuille flows are performed to study the influences of the strength of the solid–fluid coupling, the fluid temperature, and the density of the solid wall on the velocity slip at the fluid boundary. For weak solid–fluid coupling strength, high temperature of the confined fluid and high density of the solid wall, the large velocity slip at the fluid boundary can be obviously observed. The effectiveness of the corrected second-order slip boundary condition is demonstrated by comparing the velocity profiles of Poiseuille flows from MD simulations with that from continuum.     

Development of human-machine interface for teleoperation of a mobile manipulator

Human-robot control interfaces have received increased attention during the past decades for conveniently introducing robot into human daily life. In this paper, a novel Human-machine Interface (HMI) is developed, which contains two components. One is based on the surface electromyography (sEMG) signal, which is from the human upper limb, and the other is based on the Microsoft Kinect sensor. The proposed interface allows the user to control in real time a mobile humanoid robot arm in 3-D space, through upper limb motion estimation by sEMG recordings and Microsoft Kinect sensor. The effectiveness of the method is verified by experiments, including random arm motions in the 3-D space with variable hand speed profiles.     

高职院校顶岗实习管理信息化平台中的动态菜单技术

高职院校顶岗实习管理信息化平台的设计采用asp.net技术,基于B/S结构,使用起来非常方便,管理学生顶岗实习的效率更高。为了方便维护,系统采用了动态菜单技术,并且管理员可以很方便的控制其他用户菜单功能的有效性。