Modeling degradation ratios and nutrient availability of anthocyanidin-accumulating Lc-alfalfa populations in dairy cows

Dairy cattle eating fresh or ensiled alfalfa as the main portion of their diet often have low protein efficiency because of the rapid initial rate of ruminal protein degradation of fresh and ensiled alfalfa. Ruminal protein degradation of alfalfa might be reduced by introducing a gene that stimulates the accumulation of mono- or polymeric anthocyanidins in alfalfa. The objectives of this study were to fractionate protein and carbohydrates by in situ and chemical approaches, to evaluate in situ ruminal degradation characteristics and synchronization ratios, to determine protein availability to dairy cattle using the 2007 digestible intestinal protein/rumen-degraded protein balance (DVE/OEB) protein system, and to determine net energy for lactation using the Dutch net energy for lactation (VEM) system for 3 newly developed transgenic winter hardy anthocyanidin-accumulating T₁Lc-alfalfa populations. These T₁Lc-alfalfa populations, called ^T1BeavLc1, ^T1RambLc3, and ^T1RangLc4, had an average anthocyanidin accumulation of 163.4 μg/g of DM, whereas AC Grazeland (selected for a low initial rate of degradation) did not accumulate anthocyanidin. The basic chemical composition of the original samples, soluble and potentially degradable fractions, and degradation characteristics of crude protein and carbohydrates were similar in T₁Lc-alfalfa and AC Grazeland. The undegradable in situ crude protein and neutral detergent fiber fraction had 1.3% lower CP and 4.8% lower CHO, respectively, in T₁Lc-alfalfa compared with the amounts in AC Grazeland. The T₁Lc-alfalfa had a 0.34 MJ/kg of DM higher calculated net energy for lactation and 1.9% of CP higher buffer soluble protein compared with that in AC Grazeland. By the protein evaluation model, it was predicted that T₁Lc-alfalfa tended to have 11.9, 6.9, and 8.4 g/kg of DM higher rumen degradable protein, OEB, and intestinal available protein, respectively, compared with the amounts in AC Grazeland. The hourly OEB included an initial and substantial peak (oversupply) of protein relative to energy, which was highest in ^T1RangLc4 and lowest in ^T1RambLc3. The hourly OEB between 4 and 24 h was similar and more balanced for all 4 alfalfa populations. In conclusion, T₁Lc-alfalfa accumulated anthocyanidin, tended to have higher predicted intestinal protein availability, and had higher predicted net energy of lactation availability for dairy cattle than did AC Grazeland.     

分布式虚拟环境的可扩充性研究

讨论了与分布式虚拟环境系统扩充性相关的两类技术，一类是通过简单的硬件并行来实现系统扩容,典型的例子是多服务器并行分区技术。这类技术能够支持大规模的分布式虚拟环境(DVE)系统，缺点是费用太高;另一类技术试图通过减少服务器通信负载来实现系统容量的增加，主要包括感兴趣区域（AOI）技术，DR算法和组播技术。此外，还讨论了一些复合方法：如基于AOI的组播技术等。网络负载的减少意味着相同的硬件条件可以支持更大规模的客户,从而有助于解决大规模DVE系统的扩充性问题。     

分布式虚拟环境中基于HLA的交互仿真方法

论文通过建立基于HLA(HighLevelArchitecture)的网络通信机制,设计开发相关的联邦成员,实现了一种坦克训练模拟器视景子系统间的交互仿真方法。与DIS方法相比,HLA方法在互操作、可重用和可扩展方面具有很大的优越性,特别适合于庞大的分布式虚拟环境系统。     

实时股市行情播出系统改版及实施方案

应用多媒体资讯电视（CBNC—INFOTV）制播系统,将原有的实时股市行情播出系统进行改版,改版后的播出系统在同一播出屏幕上划分区域更合理,内容更丰富,目的是将单位时间内所创造的广告价值最大化,并通过系统流程图、连线图等方式列举了搭建播出平台的实施方案。     

一种DVE中通用的因果消息序时间管理分布式中间件

对于遵循高层体系结构(HLA)标准构建的分布式虚拟环境(DVE),时间管理服务的性能将直接影响分布式仿真的效率和正确性。目前的时间管理服务实现了两种消息排序机制:接收序和时戳序。接收序对消息按其接收顺序进行处理,实时性高,但无法正确处理接收顺序与产生顺序相违背的消息;时戳序通常指保守时戳序机制,能对消息按其产生的时间顺序进行处理,但时间开销较大,难以到达DVE的实时性要求。因此,本文以分布式中间件的方式为DVE设计实现了一种因果消息序时间管理服务,提供符合HLA标准的程序接口,使分布式仿真应用在不改变原有调用接口的情况下,能够通过中间件对消息实现因果序时间管理。实验表明,使用该中间件可以有效维护消息的处理顺序,同时时间开销小,能够较好地满足DVE的实时性要求。     

分布式虚拟环境

分布式虚拟环境是单用户虚拟环境网络化、多用户化的发展。其运行在多台计算机上,这些计算机通过网络进行连接,用户通过使用计算机实时交互,共享相同的虚拟世界。该文首先阐述了分布式虚拟环境的基本概念和特征,并在此基础上简要介绍了两种常用的分布式虚拟环境的模型结构;然后从底层介绍了分布式虚拟环境中的DIS协议,并从高层描述了相关的虚拟现实技术;最后展望了分布式虚拟环境的应用前景。     

多机器人遥操作系统分布式虚拟环境平台

针对多机器人遥操作系统,建立了多用户分布式虚拟环境。分析了多机器人遥操作系统组成以及分布式客户端操作的特点,构建了分层软件结构,并研究了虚拟环境场景控制、分布式网络传输、分布式虚拟环境一致性以及虚拟环境建模等问题。该分布式虚拟环境能够适应遥操作系统的应用,提高用户的工作效率和协作性。     

Jini平台下DVE中的协同支撑服务的设计

介绍了利用AO方法,研究与设计基于Jini平台下的分布式虚拟环境中的协同支撑服务.以一个虚拟教室场景中的协同工作为例,分析比较了在DVE下的协同应用开发中为使系统更具适应性和扩展性,AO方法比OO方法的优越性.基于AO的开发设计思路,分析了DVE下的协同支撑服务中的横切关注点,介绍了协同支撑服务实现中关键的动态编织机制,并给出了协同支撑服务的软件体系结构.     

DVE architecture based on message category

By importing the idea of P2P,and transmitting messages among clients directly into the client-server architecture,a new hybrid architecture was presented with the help of AOI technology and message category.Theoretical analysis of this architecture was presented in detail.A series of simulation experiments was carried out to verify its effectiveness.Results indicate that the new architecture produces less server message workload than traditional architectures,which can improve the scalability of DVE systems.     

Net-VE系统中动态共享状态管理方法的研究

本文介绍了net VE系统中动态共享状态管理的三种方法及其优缺点,分析了如何使用分布式数据库来管理net VE中的共享状态,讨论了与分布式数据库的接口设计、接口要完成的主要功能、数据库中要存储的对象类型、共享状态的更新策略等。