为探讨不同番鸭群体遗传多样性和亲缘关系,本研究选取24对微卫星引物,对7个番鸭群体的DNA片段进行PCR扩增及毛细管电泳产物信息检测.结果表明,24个微卫星位点在7个番鸭群体上共检测到80个有效等位基因,基因流(Nm)为2.4181,多态信息含量(PIC)为0.4561,F-统计量(F-statistic)平均为0.0937.7个番鸭群体中,福建花羽番鸭遗传参数较高,海南嘉积鸭遗传参数较低,温州麻步番鸭和法国巴巴里番鸭遗传距离最近(0.0209),福建花羽番鸭和法国巴巴里番鸭遗传距离最远(0.1641).聚类分析结果显示,7个番鸭群体被分为3个类群,余姚花羽番鸭、余姚白羽番鸭、温州麻步番鸭和法国巴巴里番鸭为一个类群.综上所述,7个群体的遗传多样性呈现中度水平,其中福建花羽番鸭遗传多样性较高,海南嘉积鸭较低;群体间呈现中度分化,有频繁的基因交流;地理群体间存在一定的遗传分化.

为研究灵芝孢子粉与大豆异黄酮对110～140日龄文昌鸡生长性能、肉品质与抗氧化能力的影响,试验选取540只110日龄文昌母鸡,随机分成3个处理组,每组6个重复,每个重复30只,试验周期30天,对照组饲喂基础日粮,处理组分别在基础饲粮中添加500 mg/kg灵芝孢子粉和300mg/kg大豆异黄酮预混剂,试验期满后,测定试鸡生长性能,采集试鸡血浆、胸肌样品,测定血液与胸肌抗氧化指标、胸肌肉质性状、肉感官评定及货架期指标.结果 表明,与对照组相比,1)大豆异黄酮组试鸡的生长末重与平均日增重均显著增加(P＜0.05),料重比降低(P＜0.05);2)灵芝孢子粉显著提高试鸡胸肌宰后24 h的pH(P＜0.05)、降低剪切力(P＜0.05);大豆异黄酮显著降低胸肌宰后45 min的a*值(P＜0.05),提高胸肌宰后24 h的L*值和pH(P＜0.05);3)灵芝孢子粉组试鸡的肉汤鲜味评分显著提高(P＜0.05);4)灵芝孢子粉可显著降低文昌鸡胸肌宰后24 h的丙二醛(MDA)与宰后45 min的挥发性盐基氮含量(P＜0.05);大豆异黄酮显著降低试鸡胸肌宰后45 min和24 h的MDA含量(P＜0.05);5)饲粮添加灵芝孢子粉与大豆异黄酮显著降低了文昌鸡血浆MDA含量(P＜0.05),灵芝孢子粉还增加了血浆谷胱甘肽含量(P＜0.05).综上,500 mg/kg灵芝孢子粉和300mg/kg大豆异黄酮预混剂均可提高文昌鸡的抗氧化能力,改善肌肉品质.二者比较,500mg/kg灵芝孢子粉作用更优.

为解决在互联网文本信息爆炸性增长的前提下,在大规模文本数据中如何发现隐含的、 有价值的潜在知识的问题,提出基于多层次文本聚类的文本知识挖掘方法,针对不同规模的文本数据进行不同粒度的聚类,实现不同层次知识的挖掘.针对最广义层次的文本知识挖掘可实现各主题事务划分,针对子级分类数据的文本知识挖掘可发现下一层次主题分类,针对自定义层次的文本知识挖掘可发现该事件中存在的具体细节.对诉求实际数据的分析结果表明,该方法可在所有诉求数据中挖掘出各种诉求主题,精确挖掘出其中的细节问题,为管理者提供数据和决策支持,提高服务效率.

改革传统数字逻辑电路实验教学模式,探索融合CDIO先进的工程教育理念,以"简易数字跑表"实验为例,从项目内容、项目要求到项目评价三个角度介绍了新的实验教学方法,使学生在"构思—设计—实现—运作"四个阶段较好地发挥主观能动性,在对整体知识结构的掌握、单一知识点的理解、工程实践能力的训练、团队协作意识的提高各个方面,均取得明显的效果.

在C语言程序设计课程的教学实践环节中,引入计算机模拟案例是培养学生计算思维能力的有效手段之一.文章从蒙特卡罗算法思想入手,针对蒲丰投针问题引出3种计算π的统计学方法,有针对性地讨论计算机随机数和模拟多种分布的随机事件,以培养学生的计算思维能力.

To improve the ability of multimedia processing on Loongson platform,the LoongSIMD instruction system of GS464/GS464E CPU core was analyzed,and the SIMD instruction level optimization method was proposed.Open source H.264 decoder of FFmpeg was finely optimized while analyzing the parallel characters of algorithms,combining Loongson distinctive architectures and performance counter,intrinsic SIMD instructions and load/store memory extension instructions were embedded in hotspot functions.The average performance is improved by 50％.This work is contributed to Loongson open source community.User experience to multimedia applications is enhanced on Loongson computers.

培养计算思维能力是大学计算机基础教学的核心目标.如何把计算机科学家的思维通过恰当的教学案例平滑地嵌入教学实践环节,是落实计算思维驱动的教学改革的关键任务.文章从C语言程序设计的高效编程思想出发,阐述结合计算机系统的存储层次结构和程序的访存局部性原理,设计矩阵乘法编程的5种递进式优化实现方式案例并给出实验结果.

为从整机系统的角度分析基于自主龙芯CPU的国产计算机功耗水平,对照ACPI标准剖析龙芯3A系统的功耗控制模式,在龙芯平台软件上实现对ACPI的支持,基于龙芯3A便携式计算机系统进行实验测试,分析整机系统在不同节能状态下的功耗数据,实验结果表明,龙芯3A计算机系统的耗能符合国家计算机节能标准,为龙芯计算机系统的热设计和国产自主计算机的节能设计提供了参考.

计算思维是融合数学思维和工程思维的重要科学思维,代表着一种普遍的态度和一类普适的技能,而大学计算机基础教学是培养学生计算思维能力的重要载体.文章基于多年大学计算机基础和程序设计课程教学工作的经验体会,结合对计算思维的认知和实践,提出计算思维驱动C语言程序设计课程教学改革的思路和建议.

Loongson laptop has a built-in EC module , it controls the power management .In combination with the power-saving modes of Loongson microprocessor , the support of static power-saving on Loongson laptop can be implemented by the intelligent control of EC module . Based on analysing various kinds of power-saving modes , the power-saving plans including Standby , STD, LID and others are implemented by making use of existing interfaces in Linux kernel .Experimental data demonstrate that these power-saving modes meet the current demands of various applications well .

Loongson 2F processor provides a register for software to scale the frequency.For producing lower power consumption of Loongson computer,this paper uses CPUFreq driver framework in Linux kernel,writes driver code of CPUFreq for Loongson 2F processor,and realizes the dynamic frequency scaling of 2F processor.An experiment to measure the power saving and performance of CPUFreq is done.Experimental results show that OnDemand adjusting strategy of CPUFreq provides better synthesized effect.

The advanced encryption standard is the mainstream encryption algorithm in the security network protocol used in Linux system. Through analysis of AES encryption algorithm,with the architecture characteristics of the Loongson platform,the method for performance optimization of AES based on the expansion of multimedia instructions (SIMD technology) is proposed. Before and after optimization,the results of data transmission using security file transfer protocol Sftp (AES encryption) shows that the Loongson SIMD optimization has reduced the time of encryption and decryption and has effectively improved the Sftp network transmission rate.

SMP clusters are the mainstream architectures in high performance computing because of their good cost performance ratio,excellent scalability and availability.A hybrid parallel programming paradigm combined intra-node shared-memory programming mode and inter-node message-passing programming mode has been becoming hot in research.In a single SMP node,whether system bus and memory bandwidths meet the CPUs and IO needs heavily affects the performance of memory-intensive applications.This paper evaluates the effect of memory access contention to performance of memory-intensive applications on a SMP cluster.The result shows that performance bottleneck exists in these SMP nodes of the SMP cluster due to deficient system bus and memory bandwidth.This quantitative analysis is beneficial to guiding large scale SMP Cluster design.

The computation of sparse matrixes is n ot regular because the reference to an array element depends on the values of th e corresponding elements of another two index arrays. In this paper, One new Ope nMP directive extension, indirect, has been proposed to improve the performance of irregular applications. This paper presented the design and implementation of this extension on an OpenMP system on Cluster. Furthermore, One realistic OpenMP application called Equake from SEPC OMPL2001 benchmarks has been used to evalua te the implementation. The results show that the performance of the function dir ectly effected by the indirect clause had been improved by 18%, and that of the whole application improved by 15%.

The OpenMP Application Programming Interface (API) is an emerging standard for parallel programming on shared memory multiprocessors because of its ease of use and incremental approach to the parallelization of sequential programs. At present, clusters of workstations or PCs have been becoming the mainstream platform for high performance computing. It is increasingly attractive to develop OpenMP parallel applications on cluster systems. This paper presents the design and implementation of OpenMP computing environment on clusters, which is based on the combination of software DSM and compiler technologies. In order to improve the system performance and enlarge the application range, many methods are introduced to adapt to clusters architecture, such as OpenMP directive extension, runtime library optimization, loop scheduling algorithms etc. Furthermore, eleven OpenMP programs from some standard benchmarks have been measured on a hardware cc-NUMA machine (SGI 2100) and the OpenMP/JIAJIA system on authors' commodity cluster of PCs. The experimental results show that the mean speedup of the OpenMP/JIAJIA system on seven processors is 4.62 and that of the SGI 2100 machine is 4.55.

企业应用集成是企业信息化建设中的关键任务.Domino作为先进的知识管理平台,具有一整套的从低级到高级的企业应用整合解决措施.文章从Domino的集成框架模型出发,详细分析讨论了Domino与异种系统的集成机制,综合比较了适用不同企业应用集成的选择方案,并以我们自主开发的基于Domino的远程网络教学系统为例,介绍了与已有的教务MIS系统的集成方法.

采用Web Cache技术提高当前Intemet性能已成为一个主流的研究领域,其功能原理就象处理器和文件系统中的多级高速缓存一样.大规模Web高速缓存系统已成为许多国家Intemet基础设施的重要组成部分.该文从三个不同访问规模的代理Web Cache的跟踪日志出发,分析了Web Cache的用户访问模式、Cache命中率、Cache服务器处理延迟等统计特征,提出基于分布式共享RAM和外存储结合的两级协同Web Cache集群技术,可以提供可扩展的高性能并行Web高速缓存服务.