Design and Simulation of Low Complexity Frequency Hopping Systems Using LDPC Codes

跳频通信是现代军事无线通信抗干扰的主要手段，对于在恶劣的电磁环境中保障畅通的通信指挥，具有重大的军事意义。同时跳频通信技术不仅具有优良的抗干扰性能，而且拥有多址组网性能，在民用移动通信中也得到了广泛的应用。目前，跳频通信正在向更高的跳频速率、更强的抗干扰能力和更低的实现复杂度发展。跳频通信系统中的信道编码技术是提高系统性能的关键技术，同时也是跳频通信系统中复杂度较高的模块之一。 为了在保证性能的前提下，降低跳频通信系统复杂度，本文提出了两套方案。第一套方案是从降低编码技术本身复杂度的角度出发，采用低实现复杂度的EG-LDPC码来代替随机构造的LDPC码。仿真结果显示：无论在部分频带干扰信道还...Frequency-hopping (FH) wireless communication systems were initially developed as a military application to permit reliable and safe communications in the face of an enemy interferer, especially in a poor electromagnetic environment. So the FH systems are of a great military significance. Due to the good anti-jamming performance and multiple access ability of FH technique, FH systems are also wide...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332006115262

基于多参数融合的铅酸蓄电池SOC估算方法研究

铅酸蓄电池荷电状态(state of charge)是电源管理系统中的重要参数,准确估算蓄电池荷电状态具有重要意义。现有铅酸蓄电池荷电状态估算方法存在不适用于实际行车环境、易受干扰、计算精度低等缺陷。在开路电压法与安时积分法结合的基础上提出一种改进SOC估算方法,研究结合多个参数并引入权值w的SOC初始化算法,在SOC估算过程中根据实时温度校正电池容量,可以提高计算精度,符合工况。实验结果表明:此SOC估算方法具有很好的鲁棒性,最大估算误差小于3%

Sound Quality Analysis and Prediction Modeling of Forklift Trucks Based on Grey System Theory

为了研究灰色系统理论在声品质预测建模方面应用的有效性,对5款3吨位叉车在怠速和额定转速工况下的30个车内外辐射噪声样本进行了研究。以烦躁度为主观评价指标,采用等级评分法进行了主观评价实验。运用Artemi S软件分析计算了主要心理声学客观参数。选取了响度、尖锐度、粗糙度和抖动度为主要分析对象;运用灰色系统理论算法分析了烦躁度与心理学客观参数的相关性,得到各相关系数。证明了所取心理学客观参数与烦躁度之间具有较高的相关性。基于灰色系统理论的GM（0,N）模型,建立了烦躁度的预测模型,并对预测模型进行了误差检验。结果表明基于灰色系统理论所建立的烦躁度预测模型具有较高的精度,即预测值能够较接近人的主观感受。To discuss the application effectiveness of grey system theory in sound quality prediction modeling, 30 radiation noise samples of 5 different 3 tonnage forklifts under the conditions of idle and rated speed were taken as the research object, and subjective evaluation experiment was carried out with grading method taking annoyance as subjective evaluation index;the primary objective psychology acoustical parameters were calculated with ArtemiS, and the loudness, sharpness, roughness and fluctuation were selected as the main analysis object;by using the grey system theory, the correlation between the annoyance and the objective parameters of psychology was analyzed, and the correlation coefficient was obtained;it was proved that the correlation between the objective parameters and the annoyance was high.Based on the GM（0,N） model of grey system theory, the prediction model of annoyance was established, and the error test of the prediction model was carried out;results showed that the prediction model based on grey system theory had higher accuracy, that was to say and the prediction of value was more close to human＆#39;s subjective feelings.福建省科技重大专项（2015HZ0002）资

Review of sea anemones compound and bioactivity

海葵(sea anemone)又名海菊花,多指腔肠动物门(Coelenterata)珊瑚虫纲(Anthozoa)海葵目(actiniaria)动物。海葵一般分为爱氏海葵科、链索海葵科、细指海葵科、投海葵科、固边海葵科和绿海葵科等6科37种[1]。海葵体型大多呈圆筒状,触手以辐射对称状在口周围形成数轮,广泛分布在热带和温热带海域,主要固着在海中岩石上或泥沙中。我国海域均有分布

Focus facula measurement in graphene preparation by laser chemical vapor deposition

激光化学气相沉积(Laser Chemical Vapor; Deposition,LCVD)石墨烯制备受聚焦光斑影响很大。实时检测光斑,可实现石墨烯LCVD; 法可控制备。设计聚焦光斑测量光学系统,提出一种基于圆拟合的改进算法检测光斑中心和半径,计算、标定光斑面积。该方法在圆拟合基础上加入了二值化、形态; 学处理及连通性判别等预处理方法。实验表明,该方法测得圆心位置与真值误差平均为5. 58 pixel,光斑面积与真值误差平均为1. 93 *; 10~(-9) m~2,优于传统的重心法和霍夫检测法,具有较快的计算速度和检测精度,可实现LCVD; 法制备石墨烯实验中聚焦光斑的非接触式测量,且对其他激光加工工艺的质量控制有借鉴意义。The preparation of graphene by laser chemical vapor deposition(LCVD) is; highly affected by the focal spot. Real-time measurement of light spot; can be realized controllable preparation of graphene by LCVD method. The; measuring optical system of focal facula was designed,and an improved; method based on circle fitting method was presented to detect center and; radius of focal spot, then focal spot area was calculated and; calibrated. This method introduces some pretreatment methods, such as; binaryzation,morphology processing, connectivity discrimination.; Experiments show that the measured center position has average error of; 5. 58 pixel with true value, spot area has average error of with true; value. It is better than the traditional gravity method and Hough; algorithm and has faster computing speed and precision,which can realize; non-contact measurement of the focus facula, and this study is of; significance for quality control of other laser processing technology.国家自然科学基金项目; 福建省科技计划重大专

Algorithm of Multicast Network Topology Inference Based on Packet Loss Rate

在分析现有的网络拓扑推断算法的基础上,提出一种改进的基于丢包率的多播网络拓扑推断算法。结合接收节点的层次信息、汉明距离及节点接收的探测包数量,能够同时推断网络拓扑结构和链路丢包率,并根据链路丢包率的估计值动态地调整拓扑推断的判决门限值,提高了推断的准确性。仿真实验证明,与现有算法相比,该算法具有更好的性能。By analyzing the existing network topology inference algorithms,this paper presents an improved multicast network topology inference algorithm based on packet loss rate.It combines the hop count of receivers,the Hamming distance and the number of received probes and can infer multicast network topology and loss performance simultaneously.It adapts dynamically the value of threshold according to the estimation of link packet loss rates,it improves the accuracy of the inference.Simulation results show that compared with the existing algorithms,this algorithm has better performance.福建省自然科学基金资助项目(2006J0044

Joint decoding algorithm of LDPC codes

在加性高斯白噪声(AddITIVE WHITE gAuSSIAn nOISE,AWgn)信道中设计一种低密度奇偶校验(lOW-dEnSITy PArITy-CHECk,ldPC)码的最大似然译码算法是一项具有挑战性的工作。麦克斯韦译码算法在二进制擦除信道下具有优越的性能,但把这种算法移植到其他信道却非常困难。引入了信道转换的思想实现两个不同信道之间的转换,并利用该方法成功地将麦克斯韦算法应用到AWgn信道中,提出了一种将信度传播算法和麦克斯韦算法有机结合的联合译码算法,即信度传播-麦克斯韦译码算法,该算法可缩小与最大似然译码算法之间的性能差距。仿真表明,该译码算法可打破大多数小陷阱集从而获得比信度传播译码算法更低的误帧率,并且可消除大多数信度传播译码后出现的小错误。Designing a realizable maximum likelihood(ML) decoder for low-density parity-check(LDPC) codes is always a challenging work over an additive white Gaussian noise(AWGN) channel.Although Maxwell decoder is well known for its excellent performance over the binary erasure channel(BEC),it seems that generalizing this algorithm for other channels is difficult.This paper introduces an idea called channel transformation which could realize the conversation between two different channels.A Maxwell decoder is applied to an AWGN channel.In terms of this method,and a joint decoder-BP-Maxwell(BM) decoder is proposed which combines a belief propagation(BP) decoder and a Maxwell decoder,to reduce the gap to the ML decoder in performance.Simulation results show that the BM decoding algorithm could break most small trapping sets to accomplish a lower frame error rate(FER).Moreover it also could eliminate most of the small-scale errors compared with a BP decoder.国家自然科学基金(60972053)资助课

智能电表运行状态评估技术研究综述

智能电能表运行状态评估包括可靠性分析、电能表故障分析以及电能表可靠性寿命预计；针对目前智能电能表运行状态评价研究所必须面对的问题，对当前应用于智能电表状态评估的质量评价方法、异常分析和故障预测算法、寿命预测算法等内容进行了梳理和对比，盘点智能电表运行状态评价技术的研究现状和最新研发进展；最后从智能电表数据特点的角度阐释了目前应用算法的特点和不足，并探讨了研究基于多源数据融合技术的智能电表运行状态评估技术的必要性、可行性和努力方向，为智能电表数据数据分析技术和状态评估技术提供可靠的借鉴意义。国家电网公司科技项目资助（基于多源数据融合的智能电能表运行状态评价技术研究及应用)（JL71-16-006

数据挖掘的技术与商业定义及其研究对象

本文在对数据挖掘考察的基础上,从技术角度和商业角度对数据挖掘的概念予以界定,并探讨了数据挖掘在知识发现中的地位,明确了数据挖掘的对象和对该领域的研究方向.国家社会科学基金资助(03BTJ014);; 国家统计局统计科学研究重点项目基金资助(LX2002-2

Effect of ZnF2 Coating on Performance of LiNi0.5Mn1.5O4 Cathode Material for Lithium-ion Batteries

采用溶胶-凝胶法制备了LiNi0.5Mn1.5O4正极材料，并利用Zn F2对其表面进行包覆改性。XRD、SEM和TEM测试表明，包覆处理不影响材料的晶体结构，2%(质量分数，以LiNi0.5Mn1.5O4质量计，下同)的Zn F2在LiNi0.5Mn1.5O4表面形成了约7 nm厚均匀包覆层。对未包覆的LiNi0.5Mn1.5O4和1%、2%、3%的Zn F2包覆后的LiNi0.5Mn1.5O4的电化学性能进行了考察，发现Zn F2包覆能够减弱电解液与LiNi0.5Mn1.5O4正极材料之间的相互作用，稳定电极表面，提高材料的电化学性能。其中，2%Zn F2包覆样品表现出最佳的循环性能和倍率性能，0.2C电流倍率下循环200圈后，其放电比容量维持在109.0 m A·h/g，保持率为79.7%；5 C电流倍率下循环500圈后，放电比容量维持在94.2 m A·h/g，保持率为85.6%