基于AT89S52的家庭智能浇花器的设计

设计了家庭智能浇花器,实现花卉的自动浇水.利用单片机实现自动浇花,根据不同的花种,设置了不同的控制方式,即定时定量浇花方式与根据湿度浇花.定时定量浇花是实现每天在规定的时间自动打开电磁阀浇花,根据不同的花卉所需水量不同,用一个按钮来设置浇花时间的长短,即电磁阀打开的时间,其余时间电磁阀闭合,水流不经过;根据湿度控制浇花...     

Control of polishing of diamond films using microactuation and an atmospheric pressure plasma

In this work, the diamond deposited by hot filament chemical vapor deposition (CVD) is polished using an atmospheric pressure plasma. In order to position the film relative to the plasma, a microactuator system is designed using a stack of domed piezoelectric actuators. A dynamic model based on the physical system is developed and the model parameters are measured experimentally. A system based on laser triangulation is used to measure the position of the diamond film relative to the plasma. Control techniques are used to reduce the oscillations during actuation and to eliminate the steady state positioning error. With the application of feedback control, the overshoot is reduced to 2% and the settling time is reduced to 0.3 s. A preliminary set of experiments is performed to relate process parameters to the final surface roughness of the diamond film. The parameters studied include the film's time of exposure to the plasma, the height of the film relative to the plasma, and the distance from the film to the center of the plasma. It is found that the optimum exposure time is 15 min and the reduction of surface roughness is greatest when the distance between the film and the plasma is at a minimum. The best results are obtained when the top of the film is even in elevation with the tip of the top electrode. The diamond film is translated laterally along the plasma. When feedback control is not used, there is no change in the surface roughness. With feedback control implemented, the surface roughness of the diamond film is reduced by 33%.     

图像边缘提取的定位误差产生机理分析

本文分析了使用Dmarr的LOG方法检测图像边缘时,零交叉点定位误差的产生机理,指明边缘中心邻域关于边缘中心不对称是造成零交叉点定位误差的主要原因,各类边缘的零交叉点是否定位准确与噪声存在与否并无直接的联系,关键在于噪声是否破坏了边缘相对其中心的奇函数特性。     

大位宽情况下的回滚式循环冗余校验算法

为解决大位宽变长数据包情况下包尾数据的循环冗余校验(CRC)32算法处理存在的臃肿低效问题,将循环冗余校验算法变换为矩阵线性运算,利用逆矩阵反向回滚运算,得到正确的CRC运算结果;并在FPGA上进行了实验验证。结果表明：回滚运算的算法可行,并且实现简单,资源占用少。在512 bit位宽的情况下,回滚算法使得资源占用降低到了传统算法的15%;综合耗时降低到了传统算法的30%,布局/布线的耗时降低到了传统算法的40%。     

PB技术对数据库系统的管理方法

PowerBuilder的主要特色是方便有效的访问和管理数据库。PB技术对数据库的管理是通过三个重要的环节实现的。一是创建一个好的数据库；二是编制应用程序创建数据窗口；三是建立数据窗口与数据库的连接。     

集成计数器74LS161的逻辑功能扩展

MSI可编程计数器74LS161是同步二进制加法计数器,常规使用是构成各种不同进制的加法计数器。文中探讨了MSI可编程计数器74LS161的逻辑功能扩展问题,目的是探索MSI可编程计数器进行非常规使用改变应用方向的逻辑修改技术,即对可编程计数器74LS161的状态输出进行逻辑修改,改变计数规律,将状态输出反馈到预置数输入端实现“次态一预置数”的时序关系,从而实现逻辑功能扩展。所述方法的创新点是提出了MSI可编程计数器改变应用方向的逻辑修改方法。     

基于Linux操作系统下串口调试助手的设计

为了方便在Linux操作系统下进行串口调试以及能在嵌入式系统开发板上直观地观察到串行数据传输,在Redhad 9.0下的Qt Designer编程环境下设计了串口调试助手。首先在Qt下以一种图形化的编程方式完成串口调试助手界面的设计,再将其生成源代码,然后在源代码中添加串口驱动,完成串口调试助手的设计。经实践证明,该串口调试助手在Redhad 9.0操作系统上运行良好。利用交叉编译程序将其移植到S3C2410的Linux 2.4上后也能够正常运行极大地方便了调试工作。     

位相板紧贴全息图的加密记录

本文提出紧贴加密的新方法,将加密位相板紧贴全息干版,使全息记录的物光和参考光同时获得位相调制,不但提高了全息图的防伪能力,而且由于位相板紧贴全息图,解密时对位相板只需进行二维甚至一维的调节,即可获得原物光的共轭再现,避免了对位相板繁琐的多维复原调节,增强了实用性。     

A New Method Modifying Single Miller Feedforward Frequency Compensation to Drive Large Capacitive Loads: Putting an Attenuator in the Path

A new method to compensate three-stage amplifier to drive large capacitive loads is proposed in this paper. Gain Bandwidth Product is increased due to use an attenuator in the path of miller compensation capacitor. Analysis demonstrates that the gain bandwidth product will be improved significantly without using large compensation capacitor. Using a feedforward path is deployed to control a left half plane zero which is able to cancel out first non-dominant pole. A three stage amplifier is simulated in a 0.18 μm CMOS technology. The purpose of the design is to compensate three-stage amplifier loading 1000 pF capacitive load. The simulated amplifier with a 1000 pF capacitive load is performed in 3.3 MHz gain bandwidth product, and phase margin of 50. The compensation capacitor is reduced extremely compared to conventional nested miller compensation methods. Since transconductance of each stage is not distinct, and it is close to one another; as a result, this method is suitable low power design methodology.     

基于椭圆斑点序列图像估测清晰成像的方法

采用透镜成像的单目视觉测量模型进行位移测量时,需要知道清晰成像斑点的中心坐标.当物体发生位移时,为了获取清晰成像斑点,需要调整透镜位置,使其服从透镜成像规律.但是由于透镜制造缺陷,其焦点不是理想的一个点,而是一段小区域,当成像接近清晰时,通过微动调整透镜位置,成像清晰程度基本不变,这就是成像的不敏感区域,又称死区,因此...     

Design of differential power analysis resistant crypto chip based on time randomization

Differential Power Analysis (DPA) is an effective attack method to break the crypto chips and it has been considered to be a threat to security of information system. With analyzing the principle of resist-ing DPA, an available countermeasure based on randomization is proposed in this paper. Time delay is in-serted in the operation process and random number is precharged to the circuit during the delay time, the normal schedule is disturbed and the power is randomized. Following this methodology, a general DPA re-sistance random precharge architecture is proposed and DES algorithm following this architecture is imple-mented. This countermeasure is testified to be efficient to resist DPA.     

基于扩展卡尔曼滤波器的超紧耦合GPS/INS组合导航系统设计

提出了一种组合导航设计方案,通过将滤波器得到的多普勒频移信号反馈给GPS接收机跟踪环,实现了超紧耦合,提高了组合导航系统在高动态和干扰条件下的性能.采用了非线性动态模型并对其进行了线性化,提高了导航精度并减小系统计算量;应用用一阶高斯马尔可夫模型描述不同的惯性传感器误差,最后给出了扩展卡尔曼滤波器的具体算法.     

多尺度多特征仿生人脸识别

本文使用Daubechies正交小波变换对人脸图像进行二次小波分解:首先对第二次小波变换低频子图像进行PCA分析。运用邻域法进行分类得到距离隶属度。利用模糊分析提取出候选样本,对候选样本第一次小波变换的低频子图像进行PCA分析,运用最近邻域法进行分类得到最终识别结果。实验表明:小波变换预处理得到多尺度多特征;分类结果之间具有一定的互补性,同时可以提高分类性能。     

Contrast independent motion detection using 'inverse pair' spatio-temporal edge detectors

Detection of motion by methods such as background differencing is bedevilled by noise-induced changes which can appear as motion signals. It is therefore important to have methods which extract motion in a more fundamental way. To achieve this it is necessary to remember that motion is a spatio-temporal (3D) phenomenon. This problem is approached by applying 'inverse pair' filters, the outputs of which are combined to give a response which is invariant to contrast. The output response is also invariant to direction of motion within the image.     

准恒频电流滞环控制的死区补偿

详细分析了逆变器的死区效应,结合变环宽准恒频滞环控制的特点,本文采用按电流极性对脉冲给予补偿的方法,并对环宽进行修正。另外针对零电流箝位现象和滞环控制本身造成的过零点附近电流极性难以检测的问题,采用零电流附近极性给定策略;针对峰值处占空比为1的情况,通过对环宽进行限幅,减小电压波形的畸变。仿真和实验验证了该方案的可行性...     

Push forward link-level scheduling for network-wide performance

A virtual circuit network with arbitrary topology is considered. The traffic streams follow prespecified routes, different in general for each stream, to reach their destination. A fluid traffic model is adopted and a processor sharing service discipline is considered. A policy is proposed for setting adaptively the fractions of the transmission capacity, which is allocated to the different traffic streams in the processor sharing discipline at each link. The amount of traffic arrived at the originating node of each link is measured for each stream. The fraction of the link capacity allocated to each stream is set to be proportional to the measured traffic. The traffic is measured continuously and the fractions are updated regularly based on the most recent traffic measurements. It is shown that eventually, the transmission capacity allocated to each stream converges to a quantity proportional to the average rate of the stream. Hence, if the capacity condition is satisfied, sufficient fractions of the capacity are allocated at each link for each stream. End-to-end performance guarantees are provided, if the traffic is regulated. The policy is distributed since each link adjusts the service fractions based on observations of the traffic arriving at its originating node only. Furthermore, it is adaptive since no information on the traffic characteristics is needed for the application of the policy     

皮秒拍瓦激光的参数测量系统可靠性分析

皮秒参数测量系统用于提供皮秒拍瓦激光系统的各项状态参数,协助激光系统达到预期的技术指标。针对皮秒拍瓦激光系统的技术指标,皮秒参数测量系统将提供压缩脉冲的能量、脉宽、远场、信噪比等参数。为了判断参数测量系统的工作性能,采用均方根(RMS)误差来描述测量系统的可靠性。经过实验测试,能量测量单元的测量范围为10～1000J,标定实验数据的RMS误差为2.2%。脉宽测量单元的时间测量范围为0.5～18.0ps,时间分辨率为0.07ps,测试数据的RMS误差为3%。远场测量单元的空间测量范围为150倍衍射极限(DL),空间分辨率为0.3倍DL,测试数据的RMS误差为0.15%。信噪比测量单元的时间测量范围为30ps,时间分辨率为0.3ps,动态范围为106。基于拍瓦实验提供的测试数据表明,皮秒参数测量系统能够稳定可靠地提供以上参数的实时测试数据,实现拍瓦装置的运行状态诊断功能。     

光学元件表面疵病标准板系统设计

为解决大口径光学元件表面疵病检测设备的精确测量、校准和溯源问题。设计了用于标定表面疵病检测系统的标准板,通过电子束曝光将定标图案转移至掩模板,再采用反应离子束刻蚀的方法制作标准板。通过扫描电镜测量标准板上各标准线的真实线宽尺寸,并以扫描电镜测量结果为参考值标定大口径表面疵病检测系统。利用所设计的标准板标定基于散射成像法的大口径表面疵病检测系统。结果表明,当疵病线宽尺寸大于45 μm时,疵病的散射像满足几何成像原理,当疵病宽度尺寸小于45 μm时,需按标定结果进行计算。     

Optimization of two-dimensional radome boresight error performanceusing simulated annealing technique

A systematic approach to radome design is presented. The problem is formulated as a global optimization procedure such that the radome performance is optimized by properly adjusting the thickness of the radome layer over the entire radome surface. In this approach the thickness profile is parameterized via B-splines representation. Simulated annealing technique is applied to finding the best thickness profile so that the maximum boresight error is reduced to as small as possible over the entire range of the antenna look angle. A two-dimensional design example is given. The best possible thickness profile is found and the boresight error is reduced considerably compared to that due to a uniform layer. The method is general and can be applied without difficulty to other realistic three-dimensional radomes of arbitrary shapes     

Utility-based power control for a two-cell CDMA data network

Power allocation across users in two adjacent cells is studied for a code-division multiple access (CDMA) data service. The forward link is considered and cells are modeled as one-dimensional with uniformly distributed users and orthogonal signatures within each cell. Each user is assumed to have a utility function that describes the user's received utility, or willingness to pay, for a received signal-to-interference-plus-noise ratio (SINR). The objective is to allocate the transmitted power to maximize the total utility summed over all users subject to power constraints in each cell. It is first shown that this optimization can be achieved by a pricing scheme in which each base station announces a price per unit transmitted power to the users, and each user requests power to maximize individual surplus (utility minus cost). Setting prices to maximize total revenue over both cells is also considered, and it is shown that, in general, the solution is different from the one obtained by maximizing total utility. Conditions are given for which independent optimization in each cell, which leads to a Nash equilibrium (NE), is globally optimal. It is shown that, in general, coordination between the two cells is needed to achieve the maximum utility or revenue.