基因表达编程算法的冻融系数预测研究

冻土融沉系数是冻土融化后沉降量的直接反映,影响融沉系数的主要因素有粉黏粒含量、未冻土的含水率、干密度、液塑限等.为了定量化的描述融沉系数与各影响因素之间的关系,引入基因表达式编程算法进行五维空间上的函数挖掘,将函数表达式基因化,通过Karva语言对基因进行编码,利用达尔文的进化理论,初始种群经过若干代的交叉变异,最终得出了最优化的个体,即最优函数表达式.结果表明:得到的函数表达式能综合反映各因素与融沉系数之间的关系;对测试样本进行预测,R2值为99.50%,实现了融沉系数预测的高精度和直观化,为融沉系数预测提供了一种新的智能化方法.     

变系数mKdV方程的椭圆函数周期解

通过引入一个波变换,将变系数mKdV方程约化为常微分方程.假设方程的系数满足特定的约束条件,借助符号计算软件Mathematica和扩展的F-展开函数法,在拟设法、齐次平衡原理和Jacobi椭圆函数展开法的基础上,求得了精确解的浓缩公式.利用第一类椭圆方程中P,Q,R的不同取值与相应的F(ξ)值之间的关系,从解的浓缩公式中,得到了丰富的显式精确解,特别是以两个不同的Jacobi椭圆函数表示的精确解.在极限的情况下,即当模疗m→1或m→0时,这些解退化为相应的类孤立波解和三角函数表示的精确解.该方法具有直接、简洁的特点,可以用来求解更多的在数学物理、自然科学和应用科学等领域出现的非线性偏微分方程的精确解.     

基于MPEG压缩域的视频数字水印算法的研究与实现

根据MPEG压缩视频的原理，提出了一种基于MPEG压缩域面向DCT变换的视频数字水印算法，并详细叙述了将水印信息经m序列调制后嵌入到IVOP帧的色度DCT变换的直流系数中的视频数字水印算法设计和实现的过程。实验证明，该视频数字水印算法在不降低视频质量的基础上，能够抵抗多种干扰和攻击，具有良好的稳定性和鲁棒性，并验证了以上分析。     

关于整系数多项式无有理根的一个判别法的注记

对整系数多项式无有理根的一个判别法一文中的条件进行分类讨论,得到几类不可约多项式的判别法,较好地推广了Eisenstein判别法.     

大口径机枪双头弹空气阻力系数的实验研究

介绍了大口径机枪双头弹空气阻力系数的 2种实验方法和实验结果。采用模型风洞测试和实弹射击的方法获得了大口径机枪双头弹弹头飞行的空气阻力系数 ,对 2种方法所得的阻力系数进行了比较分析。分析结果表明 ,2种方法所得结果基本接近 ,双头弹前弹头所测得的阻力系数跟风洞测试攻角为 0°时的测试结果接近 ,后弹头的阻力系数与风洞测试攻角为 4°时的结果相近 ,说明前弹头对后弹头具有一定的空气干扰 ,实弹射击更能体现各种综合因素对弹头飞行的影响     

Arsenic hyperaccumulator Pteris Vittata L. and its arsenic accumulation

An arsenic hyperaccumulator Pteris vittata L. (Chinese brake) was first discovered in China by means of field survey and greenhouse cultivation. Field survey showed that Chinese brake had large accumulating capacity to arsenic; the orders of arsenic content in different parts of the fern were as follows: leaves>leafstalks>roots, which is totally different from that of ordinary plants; bioaccumulation coefficients of the above ground parts of the fern decreased as a power function of soil arsenic contents. In the control of pot trials with normal unpolluted soil containing 9 mg/kg of arsenic, the bioaccumulation coefficients of the above ground parts and rhizoids of Chinese brake were as high as 71 and 80 respectively. Greenhouse cultivation in the contaminated soil from mining areas has shown that more than 1 times greater arsenic can be accumulated in the leaves of the fern than that of field samples with the largest content of 5070 mg/kg As on a dry matter basis. During greenhouse cultivation, arsenic content in the leaves of the fern increased linearly with time prolonging. Not only has Chinese brake extraordinary tolerance and accumulation to arsenic, but it grew rapidly with great biomass, wide distribution and easy adaptation to different environmental conditions as well. Therefore, it has great potential in future remediation of arsenic contamination. It also demonstrates important value for studies of arsenic physiology and biochemistry such as arsenic absorption, translocation and detoxification mechanisms in plants.     

Randomized unit root processes for modelling and forecasting financial time series: Theory and applications

This paper considers the problems of statistically analysing the levels of financial time series rather than their differences, which are often equivalent to returns and which are traditionally analysed in econometric modelling. This focus on differences is a consequence of the inherent nonstationarity of the levels, and hence analysing the latter requires introducing an alternative framework for modelling nonstationary behaviour. We do this by considering randomized unit root processes, arguing that these can have a natural interpretation in the financial context. The paper thus develops methods for testing for randomized unit roots and for modelling such processes. It then applies these techniques to various financial time series, so as to ascertain their potential usefulness, particularly for forecasting.     

基于DSP开集说话人识别系统的实时实现

为了给说话人识别系统的应用提供一个较为重要的技术途径,利用美国TI公司生产的TMS320VC5402DSP作为CPU开发的DSP(D igital S ignal Processor)系统,实时实现了一个基于说话人自适应的开集说话人识别系统。为了提高系统的处理速度和识别的准确性,系统采用少量的语音数据产生说话人模型,在改进的矢量量化方法的基础上,利用一种说话人自适应的阈值处理算法,有效地提高了系统的识别率。同时对降低算法的计算量、数据的存储量进行了较深入的研究。从说话人识别的响应时间、训练时间等综合方面考虑,使真正意义上的说话人识别系统在DSP芯片上实现成为可能。实验表明,该系统在普通机房条件下,可以取得较好的实验效果,系统识别时间小于1 s,完全满足实时性的要求。     

皖西大别山区人地关系综合评价

为了协调皖西大别山区人地关系,在建立区内人地关系综合评价模型的基础上,对区内人地关系进行了综合评价,评价结果值为５９．７根据评价因子的匹配系数（Ｃｃ）,发现区域开发中资源条件和环境条件较好,但社会问题和经济问题比较突出,对此提出稳定和持续发展区内人地关系的对策,加皖西大别山区经济的发展．     

解析函数的一类子族

研究了在单位圆内解析的函数类G_n(α,β),利用解析函数的性质和不等式技巧进行讨论,得到了这类函数的包含关系、系数估计等性质及这类函数的一个充分条件.