湘中山地土壤线虫(Nematoda)生态地理群的研究

作者对湖南南岳衡山和长沙岳麓山土壤线虫进行了两年多的定位研究,共获得18511条土壤线虫标本.经分类鉴定,计有24个种,分属6目10科18届

Effects of Different Sallow Water Acoustic Channel Models on Error-correction Code Performance Analysis

由于水声信道复杂多变,很难进行信道建模,迄今为止并没有一个标准的统计信道模型。针对不同的研究对象,往往需要采用不同的水声信道模型,而评估信道建模差异对研究结论的影响则具有重要意义。从信道纠错码角度,在分析时不变信道模型、时变信道模型和准静止衰落信道模型的基础上,结合高效信道纠错码(以ldPC码为例),讨论了水声信道模型差异对研究纠错码性能可能带来的影响,为实际设计水声通信系统提供参考。仿真结果表明,尽管不同信道建模方式对系统解码的具体信噪比数值要求不大相同,但编译码参数优化设计的方案基本一致,海试数据则进一步验证了上述结论。There have been no standard statistical channel models for the underwater acoustic( UWA)channel as a result of the complex and variability of UWA channel.Different UWA channel models are required for different purposes during the UWA communication research.It is important to evaluate the effect of different UWA channel modeling on research conclusions.From the perspective of channel errorcorrection code,the effects of different channel models on channel error-correction code( taking LDPC codes as an example) design are investigated by analyzing several UWA channel models,including timeinvariance model,time-variance model and quasi-static fading model adopted in UWA communication simulation.The simulation results show that the optimized designs of coding parameters are almost the same,although different channel modeling usually requires different signal-to-noise ratio for decoding.The sea test data are adopted to further verify the conclusions.国家自然科学基金项目(41176032、41376040); 中央高校基本科研业务费专项基金; 厦门大学基础创新科研基金项目(201112G020、201212G012); 高等学校博士学科点专项科研基金项目(20130121120033

Performance Analysis of Repeat-Accumulate Codes over Shallow Water Acoustic Channels

针对浅海水声信道的强多途、长时延、严重衰落等特点,需采用性能好、能够实现线性编译码便于实时处理的信道纠错码技术以提高水声通信系统可靠性的问题,提出重复累积(rEPEAT-ACCuMulATE,rA)码作为浅海水声信道的纠错码方案。建立rA码在浅海水声信道中的仿真模型,比较其在不同浅海水声信道模型下的性能,通过水池数据传输实验研究编译码参数对rA码性能的影响,并以水下图像传输实验进一步验证该编码方案。仿真和实验结果表明:rA码在浅海水声通信系统中具有较强的纠错能力,选择合适的参数会进一步提高编码增益。与TurbO码和ldPC码的编译码复杂度对比,rA码能够实现线性时间编译码,算法复杂度低,硬件实现简单,在水声通信中具有非常好的应用前景。Due to a large delay spread caused by multipath propagation and severe attenuation of the channel conditions,the Repeat-Accumulate(RA) code with short length codes,good performance and easy implementation has been proposed to enhance the reliability of the shallow water acoustic(SWA) communication system.A system model including RA coding over the SWA channels was established.As a comparison,the performance of RA codes under different ocean acoustic channel conditions was presented.The experiment in the pool was carried out to show how the encoding and decoding parameters affect the performance of RA codes,which was verified by the image transmission over channels in the pool tank.The simulation and experimental results show that RA codes have a strong error correction capability and the codes with appropriate parameters would further improve the coding gain,while they enjoy encoding and decoding in linear time and have simple hardware implementation,which have a good applied prospect in underwater acoustic communication system.国家自然科学基金资助项目(41176032);中央高校基本科研业务费专项资金资助项目(2010121032)(20112G020);厦门大学基础创新科研基金资助项目(201112G020

Efficacy, Safety, and Immunogenicity of an Escherichia coliProduced Bivalent Human Papillomavirus Vaccine: An Interim Analysis of a Randomized Clinical Trial

HPV是一种常见的生殖道感染病毒，高危型HPV持续性感染能够导致几乎所有的宫颈癌，其中HPV 16型和18型危害最大，可导致约70%的宫颈癌。预防性HPV疫苗有望减少甚至最终消灭由疫苗型别导致的宫颈癌，降低HPV相关的疾病负担。该研究是在全国4个中心5个现场的18-45岁健康女性中进行的多中心、随机、双盲、对照（戊肝疫苗）的三期临床试验，该研究结果证实我校自主研发的双价人乳头瘤病毒疫苗（大肠杆菌）具有良好的安全性、免疫原性和免疫持久性，可有效地预防HPV 16型和/或18型相关的宫颈高度癌前病变及持续性感染。 该论文报告了我校和厦门万泰沧海生物技术有限公司自主研发的双价人乳头瘤病毒疫苗（大肠杆菌）三期临床试验的期中分析结果。这是第一个进入临床试验并提交药品注册申请的国产人乳头瘤病毒疫苗（HPV疫苗），有望成为世界上第四个上市的HPV疫苗，受到世界卫生组织和盖茨基金会等国际组织的高度关注。 中国医学科学院肿瘤医院乔友林教授、我校吴婷教授、广西壮族自治区疾病预防控制中心李荣成主任医师、江苏省疾病预防控制中心胡月梅主任医师、北京大学人民医院魏丽惠教授、中国食品药品检定研究院李长贵研究员、中国医学科学院肿瘤医院陈汶教授为该论文的共同第一作者，我校张军教授、夏宁邵教授和中国医学科学院肿瘤医院乔友林教授为该论文的共同通讯作者。【Abstract】Background The high cost and insufficient supply of human papillomavirus (HPV) vaccines have slowed the pace of controlling cervical cancer. A phase 3 clinical trial was conducted to evaluate the efficacy, safety and immunogenicity of a novel Escherichia coli-produced bivalent HPV-16/18 vaccine. Methods A multi-centre, randomized, double-blind trial started on November 22, 2012, in China. In total, 7372 eligible women aged 18-45 years were age-stratified and randomly assigned to receiving 3 doses of the test or control (hepatitis E) vaccine at months 0, 1 and 6. Co-primary endpoints included high-grade genital lesions and persistent infection (over 6 months) associated with HPV-16/18. The primary analysis was performed on a per-protocol susceptible population of individuals who were negative for relevant HPV type-specific neutralizing antibodies (at day 0) and DNA (at day 0 through month 7) and who received 3 doses of the vaccine. This report presents data from a pre-specified interim analysis used for regulatory submission. Results In the per-protocol cohort, the efficacies against high-grade genital lesions and persistent infection were 100.0% (95% confidence interval [CI] = 55.6% to 100.0%, 0/3306 in the vaccine group vs. 10/3296 in the control group) and 97.8% (95% CI = 87.1% to 99.9%, 1/3240 vs. 45/3246), respectively. The side effects were mild. No vaccine-related serious adverse events were noted. Robust antibody responses for both types were induced and persisted for at least 42 months. Conclusions The Escherichia coli-produced HPV-16/18 vaccine is well tolerated and highly efficacious against HPV-16/18 associated high-grade genital lesions and persistent infection in women.This work was supported by grants from the Chinese National High-tech R&D Program (863 program, 2012AA02A408), the Chinese National Major Scientific and Technological Special Project for “Significant New Drug Development” (2018ZX09308010 and 2012ZX09101316), the National Natural Science Foundation of China (81673240 and U1705283), the Fujian Provincial Major Scientific and Technological Project (2015YZ0002), the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (CIFMS, 2017-I2M-B&R-03, and 2016-I2M-1-019) and Xiamen Innovax. 该研究获得了国家高技术研究发展计划（863计划）、新药创制国家科技重大专项、国家自然科学基金、福建省科技重大专项、中国医学科学院医学与健康科技创新工程基金以及厦门万泰沧海生物技术有限公司的资助

Applications of rate-compatible QC-LDPC codes in underwater acoustic communication

针对水声信道复杂多变、强多途和大起伏干扰等特点,提出采用码率兼容QC-ldPC码的自适应信道编码技术,以提高水声数据传输的可靠性和水声信道的信道吞吐率。建立了码率兼容QC-ldPC码在水声信道中的仿真模型,构造码率为1/2、2/3…5/6等一系列QC-ldPC码,在三种典型的水声信道中对其性能进行仿真。结果表明所设计的码率兼容QC-ldPC码在三种不同信道下可行有效,能较大地提高水声通信系统的性能。由于信道时延越长、信噪比越低,满足通信指标的码率就越低;并给出码率兼容QC-ldPC码在浅海水声信道中不同信噪比下满足通信性能指标的编码码率的查找表。码率兼容QC-ldPC码提高了水声通信的信道利用率,具有灵活的编译码性能,在水声自适应通信中具有很好的应用前景。The underwater acoustic(UWA) channel is characterized as a complex variable, strong multipath and fluctuation interference channel.Adaptive channel coding techniques which use rate-compatible QC-LDPC(RC QC-LDPC) codes are proposed to enhance the reliability of UWA data transmission and channel throughput.A system simulation model including RC QC-LDPC codes for the UWA channels is built.With constructing a series code-rates(such as 1/2, 2/3, …, 5/6) of QC-LDPC codes, the performance of the system is simulated over three different kinds of UWA channels.The simulation results show that the designed RC QC-LDPC codes are feasible and effective, can dramatically improve the performance of UWA communication system, have good applicability in UWA channels.In the case that the worse the channel, due to longer channel delay and lower signal-to-noise ratio, the lower the code-rate is taken to meet system communication indicators.The lookup table(LUT) of the rate compatible QC-LDPC codes, which meet the communication indicators of the shallow water acoustic communication system under different signal-to-noise ratios, is given.The RC QC-LDPC codes with flexible encoding and decoding performances can improve the utilization of UWA communication channel and have good application prospects.国家自然科学基金(41176032、41376040)资助项

Irregular QC-LDPC Coding Joint Adaptive Equalization for Shallow Water Acoustic Communications

浅海水声信道具有长时延、多途强、起伏快等特点,为提高数据传输可靠性,采用纠错能力强、编译码复杂度低的非规则准循环低密度奇偶校验(QC-ldPC)码作为信道纠错码方案,并联合自适应判决反馈均衡器(dfE)作为接收机结构以消除码间干扰(ISI).综合考虑非规则QC-ldPC码编译码参数选择、自适应均衡器中的最小均方差(lMS)、可变步长lMS(SVSlMS)和递归最小二乘(rlS)等3种算法的性能与复杂度权衡问题,结合福建泉港浅海域实测水声信道特性,研究了该接收机的性能.仿真结果表明:非规则QC-ldPC码的性能优于随机构造的规则ldPC码;联合自适应均衡的非规则QC-ldPC码可显著提高浅海水声通信系统性能,在较高信噪比(Snr)下,选用rlS算法时,误码率(bEr)可降为0(15db),选用低复杂度的SVSlMS算法bEr可达到10-4(18db).Shallow water acoustic channel is characterized by long transmission delay,strong multipath interference,and large fluctuation.To improve reliability of underwater acoustic data transmission,this paper use irregular quasi-cyclic low density parity check(QC-LDPC)codes as an error-correcting coding scheme,which have strong error correction capability and low coding and decoding complexity,joint adaptive equalization as a receiver structure for eliminating inter-symbol interference caused by strong multipath effect.This paper makes comprehensive considerations of optimal design problem,such as the choices of coding and decoding parameters for irregular QC-LDPC codes,the balances of performance and complexity for least mean square,recursive least squares and sigmoid variable step-size least mean square algorithms in adaptive decision feedback equalizer;combining the measurement shallow water acoustic channel of characteristics Fujian quangang Xiaocuo harbour to analyses the performance of the receiver.Simulation results show that the irregular QC-LDPC codes perform better than random structure regular LDPC codes;irregular QC-LDPC coding joint adaptive equalization can significantly improve the performance of shallow water acoustic communication system.At high SNR,when select RLS algorithm,bit error rate can be reduced to 0;when select SVSLMS algorithm with low complexity,error rate can reach 10-4.国家自然科学基金(41176032;41376040

Frequency selection and relay placement for dynamic code cooperative communication in underwater acoustic networks

以含直达路径的典型3点中继动态编码协作水声通信系统为例,研究了如何选择最优工作频率与中继节点的位置,以使系统的功耗最小、性能最优的方法。首先给出在一定通信距离情况下的最优工作频率模型,根据得到的最优工作频率来改变中继节点位置,继而得到中继节点的最佳位置。以此为基础,建立通信网络的能量消耗模型,通过最优频率-距离关系近似表达式进行能量消耗的优化,综合工作频率与中继节点位置进行选择。从理论上证明了当中继节点与信源节点和目的节点的距离相等时,工作频率选择该距离条件下的最优工作频率可使系统的功耗最小。计算机仿真实验验证了该理论的正确性。Three nodes-relay cooperative communication systems,including a direct path,are selected to study the problems of choosing the proper frequency and node locations for minimizing energy consumption.The approximate models for this frequency are proposed,when the link lengths are known exactly.The relay placement is investigated in a three nodes-relay cooperative communication system with the optimal frequency.An energy consumption model is established for the networks,and the energy consumption is minimized by the optimal frequency-distance relationship approximate expression.The relay placement and the frequency are optimized for the cooperative underwater acoustic network.We demonstrate that utilizing different frequencies has an impact on the optimal relay placement,and the optimal relay placement is equidistant on the line.The simulation results verified the effectiveness of the proposed model.高等学校博士学科点专项科研基金资助项目(20130121120033);; 国家自然科学基金资助项目(41476026,41376040);; 中央高校基本科研业务费专项资金/厦门大学基础创新科研基金资助项目(20720140506