猪人工授精和繁殖疾患的防治（续一）

第二讲母猪的生殖生理第一节母猪的内生殖器官母猪的生殖器官主要有内生殖器官(卵巢和生殖道—输卵管、子宫和阴道)和外生殖器官(包括尿生殖前庭、阴唇、阴蒂),还有副性腺体(位于子宫颈以及阴道的一些腺体)共同构成母猪的生殖器官。一、卵巢在卵巢表面皮质部有一层生殖上皮,其中发育着卵泡。卵泡由原始卵泡开始经初级卵泡发育为次级卵泡,再继续发育形成卵泡细胞,再和卵丘上的卵泡壁相连,发育为三级卵泡,最后发育为成熟卵泡。发情期卵泡体积增大,卵泡中通常只有一个卵母细胞。未成熟的卵泡退化为闭锁卵泡。发情前夕,卵泡不断增长,卵泡液增多,…     

Optimal lot sizing in an unreliable two-stage serial production–inventory system

This paper deals with a two‐stage lot sizing problem in an unreliable production environment in which the machine at the first stage (stage 1) is failure‐prone while the machine at the final stage (stage 2) is failure‐free. The process goods are obtained in batches by manufacturing and are transferred continuously from stage 1 to stage 2 where the finished goods are produced and then shipped out to customers. If the machine at stage 1 breaks down then the production of the interrupted lot is not resumed. Instead, a new production cycle is initiated after machine repair. The model is formulated assuming that the production rate of the machine at stage 1 is greater than that at stage 2 and the time to machine failure and repair time are arbitrarily distributed. Specific formulation of the model under exponential failure and exponential repair time distributions is derived and a procedure for finding the optimal production policy is presented. The dependence of the optimal production policy on the model parameters is also examined with numerical examples.     

de Bruijn序列间的映射及降级算法

通过由一个n级de Bruijn序列找出它的LOOK-UP表标签,并由该LOOK-UP表标签经修正找出n-1级LOOK-UP表标签,再由它计算出n-1级de Bruijn序列,从而建立起n级de Bruijn序列到n-1级de Bruijn序列的映射,发现de Bruijn序列间的一种内在联系,导出一类任意元de Bruijn序列的降级算法。     

A two-stage hybrid flow shop with dedicated machines at the first stage

This paper considers the problem of minimizing the makespan in a two-stage hybrid flow shop with dedicated machines at stage 1. There exist multiple machines at stage 1 and one machine at stage 2. Each job must be processed on a specified machine at stage 1 depending on job type, and then the job is processed on the single machine at stage 2.     

Minimizing total completion time in two-stage hybrid flow shop with dedicated machines

We consider the problem of minimizing total completion time in a two-stage hybrid flow shop scheduling problem with dedicated machines at stage 2. There exist one machine at stage 1 and two machines at stage 2. Each job must be processed on the single machine at stage 1 and depending upon the job type, the job is processed on either of the two machines at stage 2.     

Evaluating the efficiency of a two-stage production process using data envelopment analysis

Data envelopment analysis (DEA) has been widely used to evaluate the comparative efficiencies of production processes. Most of the DEA applications assume that production processes consist of one stage. However, many production processes such as IT investments have more than one stage. In a two‐stage production process, the first stage inputs produce intermediate outputs, which are used as inputs to the second stage to produce the final outputs. In such cases, using single‐stage DEA may result in inaccurate efficiency evaluation. To address such problems, DEA models assuming two‐stage production processes have been developed. In this paper, we extend two‐stage DEA models by considering input and output slacks. We apply our model to the data from the banking industry and compare the results with those of the previous two‐stage DEA models. Our model can identify weakly efficient units of evaluation that could not be identified by the previous models.     

de Bruijn序列间的映射及升级算法

通过由n级de Bruijn序列找出n+1级de Bruijn序列的look-up表标签,并由相应的look-up表求出n+1级de Bruijn序列,从而建立起n级de Bruijn序列到n+1级de Bruijn序列的映射,发现de Bruijn序列间的一种内在联系,导出一类任意元de Bruijn序列的升级算法。     

微博舆论的演变机制及实证分析

从时间维度刻画了微博舆论的演变过程，分别是萌芽期、形成期、爆发期、高潮期和消退期，分析了各个阶段的形成动因。以“三亚宰客门”为例，详细分析了微博舆论的演变过程，提出了微博舆论的应对策略。     

慕课背景下的螺旋式研究性学习模式探索

为了探索慕课环境下研究性学习的要素与形态,分析了慕课背景下研究性学习的系统构成及内在关系。通过对慕课背景下研究性学习与传统研究性学习的对比,分析了新环境下研究性学习的特点。构建了由五个环节组成的螺旋式研究性学习模式,即:准备阶段、分析阶段、应用阶段、总结阶段、评价阶段,并用实例予以验证。     

仿人智能控制的稳定性研究

为充分发挥仿人智能控制的优点,保证控制系统的稳定性,将控制过程分为粗调阶段、调整学习阶段、微调阶段等三个阶段,每个阶段采取不同的控制方法。在微调阶段,提出了“平均偏差”控制法,较好地解决了仿人智能控制系统的稳定性问题。同时,文中总结了在实际控制过程中为确保控制系统的稳定性而采用的几种控制方法。     

企业实施信息系统审计的途径与方法

加强和改善企业内部控制状况,建立公司内控体系是目前大部分企业发展过程中亟待解决的问题,信息系统审计作为有效的企业IT治理的手段,过程与一般审计过程一样,分为准备阶段、实施阶段和报告阶段。其中,准备阶段和报告阶段所涉及的技术方法与财务审计所运用的技术方法区别不大,而实施阶段所涉及的技术方法则具有信息技术的特色。在实施阶段,针对被审计的信息系统,审计人员所开展的工作可以分为四个层次,即调查了解、初步评价、进行符合性测试、提交报告。