Research on Underwater Color Image Compressing Coding Basing on Wavelet Transform

海洋环境具有十分重要的意义，支持对上述研究的展开和进行的重要工作之一就是解决如何将水下获取的各种信息（数据、声音、图像等）准确而高效率地进行传输。这不仅涉及到对于复杂而又窄带的水声信道需要进行有效的信道编码研究，对于大数据量的彩色图像信息高质量地进行压缩编码方法研究同样具有十分重要地现实意义。因此本论文的主要目的是为水下图像传输系统寻找一种高效的彩色图像压缩编码方法，并且在恶劣的海洋水声环境中能够具有高的容错性能，保证图像恢复的质量。为了此目的，我们研究了三种基于小波变换的图像压缩编码方案－EZW算法，SPIHT算法，SPECK算法。并对具体的样例用实验分别得到实验的结果，在分析对比实验结果的...The researches upon ocean environment are of great meaning. One important part of the researches is how to transmit multimedia information exactly and efficiently in the underwater acoustic, which includes data, voice and image transmission. It not only refers to channel coding study upon the complicated and being narrowband underwater acoustic channel, but also plays an important role in the comp...学位：理学硕士院系专业：计算机与信息工程学院电子工程系_无线电物理学号：20013000

基于VxWorks 的微型打印机心电信号图文打印设计

　介绍了在VxWorks 嵌入式实时操作系统下,利用TPμp2T 微型打印机进行心电信号图 形文字同屏打印的设计。简要介绍了微型打印机以及VxWorks 嵌入式实时操作系统,以及在所构建的 硬件平台上进行微型打印机图形文字同屏打印的设计,并介绍了将该微型打印机应用于便携式多通 道遥测心电监护系统,作为3 床病人实时心电监护的心电数据硬拷贝输出设备的工作原理

基于提升小波变换的SPECK图像编码算法

提升小波变换即第2代小波变换,可以实现图像的完全无损编码; SPECK(集合分裂 嵌入块编码)是基于小波变换的采用块状结构的图像编码算法。文中介绍了基于提升方法的整数小 波变换和SPECK图像编码算法,提出了用整数小波变换代替传统小波变换进行SPECK图像编码。实 验结果表明,在相同压缩比下,该算法比EZW (零树小波编码)在重建图像的信噪比方面有所提高,而 与SPH IT(多级树集合分列算法)接近。国家自然科学基金(60272028

Design of quadrotor based on STM32 MCU

四旋翼飞行器是一种新型无人飞行器,其结构简单,飞行稳定性强,具有很强的实用价值。基于其上述特性,提出一种以STM32单片机为核心的四旋翼飞行器的设计,主要包括飞行器的结构以及基本原理的介绍、硬件部分的设计与选择、软件部分的设计与实现。在硬件部分,主要是以STM32系列微处理器为主控核心,MPU-6050为飞行姿态测量传感器,2.4GHz全球开放频段为无线数据传输控制。其中具体各元件的作用与选择将分别从主控单元、IMU模块、电机驱动模块、无线通讯模块及电源模块进行阐述。在软件部分,主要是通过四元数算法实现姿态解算和PID算法来实现姿态控制。最后对设计出的四旋翼飞行器提出一些附加功能,使其更加人机友好化。Quadrotor is a new type of unmanned aerial vehicle with simple structure, strong flight stability and high use value.The framework designed in this paper is based on STM32 MCU.There mainly include the structure of the aircraft, the introduction of the basic principle, the design and selection of the hardware subpart, the design and implementation of the software subpart.ln the hardware part, it is mainly based on STM32 series microprocessor as the core of control, MPU-6050 as the flight attitude sensor and 2.4GHz in the world as wireless data trans- mission control .In which the choice and function of these specific components will be separately clarified as the main control unit, IMU module, motor driver module, wireless communication module and power module.In the software part, it is mainly realized through quaternion algorithm in attitude determination and PID algorithm in attitude control.Finally, the design is improved by some additional functions to make it more user-friendly

The Design of D-Class Power Amplifier and Matching Circuit

是针对20 k~30 k频段的水声换能器设计d类功率放大器和匹配电路,PWM电路相对线性电路具有效率高、尺寸小等优点,所以d类功放一般选用PWM调制,d类功放由三角波发生器、比较器、功率管以及保护模块组成,实现高效率、低失真的功率放大。d类功放的输出一般都要通过一个低通滤波器来滤除高频信号,来还原低频信号。由于水声换能器是容性负载,会产生很大的无功功率,因此需要设计匹配电路,匹配包括调谐和阻抗匹配。匹配电路的加入能大大减少水声换能器的无功功率,进而提高功放的效率,使水声换能器在工作频段内能稳定工作。The article is about D-class power amplifier and matching circuit designed for 20 ~30 k spectrum underwater sound transducer.PWM circuit is more efficient and smaller than linear circuit,so we choose PWM modulation in D-class power amplifier.D-class power amplifier is composed of triangle wave generator,comparator,power tube and protection module,realizes high efficiency and low distortion power amplification.The output of D-class power amplifier typically filters out high-frequency signals through a low-pass filter,restores low-frequency signals.Underwater sound transducer is capacitive load,and it will produce large reactive power.You should design the matching circuit,including tuning and impedance matching.The matching circuit greatly reduces reactive power of underwater sound transducer,and enhances efficiency of power amplifier,ensuring underwater sound transducer in good working condition.国家自然科学基金项目(61071150);国家自然科学基金青年项目(61001142); 厦门大学中央高校基础研究基金项目(2011121050

Comparison of fertilizer-effect models on winter wheat response to nitrogen and phosphorus fertilizers in saline soils in the Yellow River Delta

通过大田试验, 研究了黄河三角洲盐碱土地区冬小麦合适的肥料效应模型。在冬小麦生长季设置4种不同的氮磷肥用量, 根据&ldquo;3414&rdquo;试验设计8 种不同的肥效试验处理, 以探讨线性加平台、一元二次、平方根和二元二次4 种不同模型的拟合效果。结果显示, 4 种肥料效应模型的拟合结果经检验都达到极显著水平 (P&lt;0.01)。在一元肥料效应模型中, 氮磷一元二次模型拟合效果最好, 最高收益分别为7 448.3 元&middot;hm-2 和7 357.7 元&middot;hm-2, 最佳经济氮磷用量分别为254.4 kg&middot;hm-2 和98.6 kg&middot;hm-2。对比一元与二元模型, 后者拟合效果较好, 最佳经济氮磷用量分别为244.1 kg&middot;hm-2 和94.2 kg&middot;hm-2, 即氮磷肥配比为2.6∶1, 经济效益为7 432.4 元&middot;hm-2, 氮肥农学利用率为6.2 kg(籽粒)&middot;kg-1(N), 磷肥农学利用率为13.8 kg(籽粒)&middot;kg-1(P2O5)。结合拟合度、最佳经济施肥量、经济收益、肥料农学利用率和一元模型的局限性分析得出, 二元二次肥料效应模型最优, 可作为黄河三角洲地区盐碱土冬小麦氮磷肥效模型的最佳选择。</p

Novel intelligent and high performance conductivity detector for ion chromatog-raphy

结合电子测量技术和计算机智能控制技术,设计了一种新型高性能智能化的离子色谱电导检测系统。系统采用两级分布式控制方式,在有效抑制噪声的同时,能够精确并且智能化的完成离子色谱信号的放大、采集、处理、谱图显示等功能。文章介绍了该系统的硬件组成、软件设计以及系统工作的基本原理,并给出测量实例。实验结果表明系统运行良好,结果可靠,完全可应用于实际的离子色谱检测。Combined with the technology of electronics measurement and computer intelligent control, a novel conductivity detector for ion chromatography with high performance and intelligence is presented in this article. The system implements a two-level distributed control, so it can not only suppress the noise effectively, but also accomplish such functions as magnifying, gathering and processing the ion chromatography signal precisely and intelligently, as well as displaying the spectrum of the ion chromatography signal. This article introduces the hardware construction and software design of the system and the principle of the system working. A measurement instance is also presented in this paper. The experimental result shows that the system runs well and the datum are reliable, so it can be applied in practical detection for ion chromatography completely.福建省科技资助项目(2001H081);; 厦门市科技计划资助项目(3502Z2001251

Research and implementation of underwater acoustic real-time voice communication prototype based on MELP

根据水声通信的复杂信道特性,对混合激励线性预测语音编码MElP算法和低密度奇偶校验码ldPC的结合进行了研究,设计了基于ArM+dSP的多载波水声实时语音通信样机。经水池实验测试,系统表现出良好的实时性和语音可懂度性能,可分辨出不同说话人的声音。Taking the complexity of the underwater acoustic communication channel characteristics into account,the combination of mixed excited linear prediction(MELP) and low density parity check(LDPC) were studied and a multi-carrier underwater acoustic real-time voice communication prototype based on ARM+DSP was designed.By the expreimental test in pool,the proposed system showed a good real-time and voice intelligibility performance,and could distinguish the voice of different speakers.中央高校基本科研业务费专项资金资助(2010121062

产前滴滴涕或多氯联苯暴露与出生缺陷风险相关性的Meta分析

目的系统评价孕妇产前暴露于滴滴涕(DDT)或多氯联苯(PCBs)与新生儿出生缺陷风险之间的关系。方法计算机检索PubMed、EMbase、WanFang Data、VIP和CNKI数据库,搜集有关产前DDT或PCBs暴露与出生缺陷关系的病例-对照研究,检索时限均从建库至2017年2月。由2名研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用Stata 13.0软件进行Meta分析。结果共纳入14个研究,包括2 238例出生缺陷新生儿和2 355例对照新生儿。Meta分析结果显示:产前暴露于高水平的DDT会导致新生儿隐睾发生率增加[OR=1.12,95%CI(1.09,1.15),P<0.001]。而DDT暴露与尿道下裂和神经管畸形发生没有相关性。产前暴露于高水平的PCBs与隐睾、尿道下裂、神经管畸形发生也没有相关性。结论孕妇产前暴露于高水平的DDT可能是隐睾发生的危险因素。受纳入研究数量和质量的限制,上述结论尚待更多高质量研究予以验证。厦门市科技计划项目(编号:3502Z20163006);;厦门市集美区科技计划项目(编号:20142C01

漳江流域沿岸植物叶片中Si元素含量的变化

该文研究了漳江流域沿岸48种植物成熟叶片中Si元素含量及其随环境因子和在不同植物类群中的变化.结果表明,这些植物叶片平均Si含量为1.23%;不同植物叶片Si含量差异显著,含量最高的是笔管草,达5.88%;最低的是桃金娘,仅0.02%.48种植物中的17种是Si积累者,叶片Si平均含量为2.53%;31种是非积累者,叶片中Si平均含量为0.28%.从植物所属科来看,含Si量较高的主要有禾本科、木贼科、紫萁科、凤尾蕨科、鸭跖草科和桑科植物.研究还发现从上游到下游,土壤Si含量随土壤粘粒含量和含水量的升高而增加.马缨丹和鸭跖草叶片Si含量与对应土壤的有效Si含量呈正相关,桐花树和秋茄叶片Si含量与对应土壤的盐度呈正相关