鉴于现行分子系统发育分析中为应用4-状态DNA进化马尔可夫模型而采取删除同源DNA多序列比矩阵中缺失位点的数据预处理方法导致进化信息丢失、序列间进化距离的偏低估计和重建进化树枝长估算等精确性降低的问题,本文借鉴统计学中参数估计的最大似然法,提出核苷酸最大似然插补比对缺失位点的数据预处理方法.通过对3组真实同源DNA序列和系统发育模拟试验生成的虚拟同源DNA序列,基于3种预处理方法分别进行进化距离估算、系统发育重建和重建进化树枝长误差的统计等对照测试和结果分析,证实核苷酸最大似然插补和最近邻插补的数据预处理方法可在一定程度上减小序列间进化距离的偏低估计,提高DNA分子系统发育重建树枝长估算的精确度,该方法优于现行的删除比对缺失位点的预处理方法.

多态性是面向对象程序设计的四大特征之一,是课程教学的重点和难点.对多态性概念内涵进行深刻辨析,有助于更好地理解面向对象中功能多样化的实现机制.本文从多态性概念中消息的理解出发,通过实例说明了消息和函数参数、数据的不同,指出多态性描述中的消息是指函数调用、而非通常所理解的函数参数、返回值等信息载体,从而更为科学地理解多态性的内在含义和多态的实现原理,为教学质量和学习效果的提高奠定重要的基础.

程序设计基础教学过程中,学生有多种信息渠道了解课程知识点、多种信息渠道参与课程交流讨论.这一方面使得课堂教学对学生的吸引力相对降低,另一方面也给老师提供了更多渠道完成课程教学.针对这个问题,从信息化环境背景对教学存在的影响及程序设计基础课程本身的特点出发,围绕理论教学内容组织、实践环节实施、课程考核和督促方式三部分内容,以课程教学三个阶段(基础、提高、深入)为描述角度,对程序设计基础课程教学进行深入的探讨.

针对分子系统发育重建时忽略同源DNA序列中的间隔位点导致进化信息丢失和序列间进化距离偏低估计的问题,基于最小进化原理并借鉴统计学中缺失数据处理的方法,提出核苷酸最近邻插补间隔位点,对插补后序列再运用4-状态DNA进化马尔可夫模型估算序列间进化距离的方法.对3组同源DNA序列在不同方法下进行距离估算的对照测试,结果表明:5-状态的F81+gap和F84+gap模型不能有效融合间隔所携带的indel信息,反而更加低估序列间距离;改进的同类模型F81+gap′则在一定程度上降低了距离的偏低估计,而核苷酸最近邻插补处理方法可以融合DNA突变中更多的indel信息.

针对离散色调彩色图像的数据冗余特点,在游程编码(RLE)与字典编码的基础上,提出一种混合编码方式,对离散色调彩色图像进行无损压缩.实验结果表明,该方法可以取得0.1～0.6 bits/pixel的压缩后像素深度,压缩率明显优于JPEG2000无损模式,也在一定程度上优于其他适用于离散色调图像的压缩方法,如GIF和PNG等.

The current grading systems for computer programming assignments have taken correctness, efficiency, complexity, and maintainability into account. Of these four components, the most important measurement is the correctness. However, the existing grading systems still have some drawbacks. It is hard to measure college students' overall programming skills based only on their answers to a single form of programming questions. The author proposes a new approach by presenting multiple forms of computer programming questions, such as statement filling‐in, program modifying and algorithm designing, and by providing an automated grading algorithm to measure the correctness, time efficiency, space efficiency, complexity, and robustness. This proposed automated grading method has been employed successfully in the development of C programming and Delphi programming exam systems for Computer Application Ability Exam for College Students in Fujian . It has also been applied to the development of an online programming self‐testing system for Data Structure course which is offered by Fujian Agriculture and Forestry University. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 484–490, 2013

In order to acquire the optimal culture medium for Bacillus thuringiensis, and the optimal components, including cornstarch, defatted soy flour, yeast, peptone and fish meal, a orthogonal, rotational and combinative design of quadratic regression was used in experiments. Based on the experimental data, repository and principle of genetic algorithm, a searching algorithm for the optimal culture medium was designed further. Using this algorithm, the optimum section of culture medium prescription was obtained for this bacterium. Further experiments and relative analysis showed that the optimization method of culture medium for Bt based on the genetic algorithm was more effectual than conventional methods.

Bacillus thuringiensis,a spore-forming bacterium that produces insecticidal proteins during sporulation,has been deeply studied and widely used.In this paper,Bt resource database was preliminarily established,where the morphology,physiological and biochemical characterics and genotypes of Bt strains were investigated.It is helpful for the development of Bt biopesticide and the protection of other beneficial bacteria.

A number of bioinformatics programs deal with the process of translating one or more nucleic acid sequences to the corresponding amino acid sequences.The structure of a genetic code search table and searching algorithm strongly influence the speed of translation of DNA into protein.Two much faster searching methods are presented here.One is a type of blocking search,its ASL(Average Search Length) is about 7 and MSL(Maximum Search Length) is 9.The other is a particular Hash table search with non-redundancy in the table space and without collision in Hash address.Both ASL and MSL of the Hash table search are 3.Comparison between new methods and old ones had been made as well.

Bacillus thuringiensis is a spore-forming bacterium that produces insecticidal proteins known as crystalline inclusions during sporulation.Up till now,it has been isolated from many habitats,including insect cardavas,soils,stored-products,plant tissues,faeces and sericulture.The collection of B.thuringiensis was reviewed in this paper.

鉴于现今流行的面向Windows环境的软件开发平台,均未提供产生时间延迟的标准函数或方法,本文参阅有关技术资料,并依据实践,提出在Windows环境下的软件开发平台中,间接地实现时间延迟的4种编程方法,并分别讨论了各种方法实现的原理、延时的精度、应用场合和应当注意的细节;文中同时给出了不同方法的算法流程图和以Object Pascal语言描述的程序关键片段。

提出计算机考试软件中对Microsoft Word操作产生的DOC文档评分的3种实现方法:(1)扫描和解析另存的HTML文档,从中获取DOC文档内容和版面信息;(2)在Delphi平台上通过OLE构件对象访问DOC文档中各种对象的信息;(3)在Visual Basic平台上通过Office VBA获取DOC文档中各种对象的信息.同时给出了相应的算法描述和程序片段,并对3种方法进行比较.

本文提出遍历文件夹及其中子文件夹中所有文件的递归和非递归两种算法,并给出了实现算法的Pascal源程序关键片段,及算法分析.

提出在Windows系统范围内,且不影响其它进程的前提下,实现捕捉鼠标和键盘操作及其事后模拟过程的方法;并给出了程序的关键片段.

探讨在Delphi开发平台下实现Windows环境下串行通信的方法,分析了不同方法中的问题、解决方法以及适用场合,并给出了例程片段.