一种基于效益的多机器人避碰协调策略

多移动机器人系统在完成同时定位和地图构建SLAM任务时,机器人之间常常存在相互碰撞的问题,而这种碰撞的避免又不同于一般的避障,因为避障问题中的障碍物一般是不动的。为了解决机器人之间的避碰问题,提出了一种基于效益的多机器人避碰协调策略。该策略以提高多机器人系统探索效率为主,确定机器人通过交叉路口的顺序。同时考虑了动态协调避碰的情况,给出了确定机器人通过交叉路口顺序的算法。通过机器人在交叉路口实现避碰协调算法的仿真示例,对该方法的避碰协调过程进行了说明,并对仿真结果进行了分析,同时对仿真中机器人和目标位置的空间关系给出了合理的假设。     

一种面向RAID阵列的SSD设计优化方法

随着大数据时代的到来,固态硬盘已经逐渐在大型数据中心得到应用。作为使用最广泛的RAID技术,RAID5也开始应用于固态硬盘阵列,以保证数据的可靠性。然而,RAID5中校验信息需要频繁地更新,尤其在随机访问中,频繁地更新校验信息将会对固态硬盘阵列的性能和寿命造成很大的影响,针对此问题,提出PA SSD(Parity Aware Solid State Disk)控制器设计,从RAID5控制器得到校验信息的逻辑地址,在SSD控制器中设置一个缓存Pcache,暂存更新后的校验信息,并在SSD中将数据和校验分开布局,设置专门的区域存放校验信息。通过实验仿真测试,提出的方法能有效地减少校验信息对SSD的写操作,并且减少了SSD的擦除次数,提升了SSD阵列的性能和寿命。     

The use of electrochemical noise methods (ENM) to study thick, high impedance coatings

Thick, high impedance organic coatings are those class of coatings used to provide corrosion protection to naval vessels, pipelines, gasoline storage tanks, and other large structures such as bridges and plant structures. These coatings, especially the newest generations now being used in practice, can provide exceptional protection and lifetime of performance such that properly and accurately assessing and differentiating among competing coatings is a very difficult task. The standard protocol of salt fog testing (ASTM B117), immersion testing, and outdoor exposure in a corrosive environment with subjective evaluation of a coating's performance durings and after testing, does not adequatcly rank and predict coating lifetimes for new coating systems, especially for the environmentally compliant coating systems such as powder coatings (especially the thick, fusion bonded epoxy (FBE) coatings used for pipelines), two component epoxy and urethane coatings and waterborne coatings. New, objective test methods are desperately needed by users and manufacturers of coatings. A relatively new electrochemical test procedure, electrochemical noise methods (ENM), as developed by Skerry and Eden, has been shown in our laboratory to be very successful in the ranking and prediction of relative coating performance. We have used the method successfully on naval ship coatings, several pipeline coatings and other related systems, and Skerry has used them successfully on industrial maintenance coatings. We have used these methods in conjunction with electrochemical impedance spectroscopy, d.c. resistance measurements and cyclic salt fog testing of the Prohesion^TM type. In our studies of pipeline coatings, we needed to investigate thermal effects because of their extended range of use temperature. In these studies, we have discovered that electrochemical methods can be used for an in situ measurement of the T_g of coatings in electrolyte immersion. Further, the ‘plasticizing’ effect of aqueous electrolyte absorption as well as its relative irreversibility has been shown. For all coatings studied, ENM provided useful, objective, numerical data which rapidly ranks coatings and provides useful information on the relative lifetime prediction of coatings which may provide up to 30 years of service.     

(<Emphasis Type="Italic">Z,Z</Emphasis>)-6,9-Heneicosadien-11-One: Major Sex Pheromone Component Of Painted Apple Moth, <Emphasis Type="Italic">Teia anartoides</Emphasis>

(Z, Z)-6,9-Heneicosadien-11-one (Z6Z9-11-one-21Hy) was identified as the major sex pheromone component of the painted apple moth (PAM), Teia anartoides (Lepidoptera: Lymantriidae), on the basis of (1) comparative gas chromatographic-electroantennographic detection (GC-EAD) analyses, GC-mass spectrometry (MS), high-performance liquid chromatography (HPLC)-MS, and HPLC-UV/visible spectroscopy of pheromone gland extracts and authentic standards; (2) GC-EAD analyses of effluvia of calling females; and (3) wind tunnel and field trapping experiments with a synthetic standard. In field experiments in Australia, synthetic Z6Z9-11-one-21Hy as a single component attracted male moths. Wind tunnel experiments suggested that a 4-component blend consisting of Z6Z9-11-one-21Hy, (6Z,9R,10S)-cis-9,10-epoxy-heneicosene (Z6-9R10S-epo-21Hy), (E, E)-7,9-heneicosadien-6,11-dione (E7E9-6,11-dione-21Hy), and 6-hydroxy-(E, E)-7,9-heneicosadien-11-one (E7E9-6-ol-11-one-21Hy) (all present in pheromone gland extracts) might induce more males to orient toward, approach, and contact the source than did Z6Z9-11-one-21Hy as a single component. Additional experiments are needed to determine conclusively whether or not Z6-9R10S-epo-21Hy, E7E9-6,11-dione-21Hy, and E7E9-6-ol-11-one-21Hy might be minor sex pheromone components of PAM. Moreover, attractiveness of synthetic pheromone and virgin PAM females needs to be compared to determine whether synthetic pheromone could replace PAM females as trap baits in the program to monitor eradication of exotic PAM in New Zealand.     

3-溴甲基-3-甲基氧杂环丁烷的合成

以2,2-二溴甲基丙醇（BBMP）为初始原料,通过与碱发生关环反应生成3-溴甲基-3-甲基氧杂环丁烷（BrMMO）。讨论了碱的种类和用量对BBMP关环产率的影响以及反应体系中碱的浓度、反应温度和反应时间对合成BrMMO产率的影响。通过实验确定的最佳工艺条件为：BBMP与NaOH摩尔比为1.0∶1.1,NaOH醇溶液的质量分数为12%,反应温度为78℃,反应时间为4h时,BrMMO产率为65%。最终产品经元素分析、IR和1HNMR检测确定为BrMMO。该试验工艺简单,原料易得,且溶剂便于回收、污染小。     

Endohedral metallofullerenes M@C82 (M=La, Y): synthesis and transport properties

Endohedral metallofullerenes M@C_2n (M=La, Y) were synthesized by the arc-discharge method using optimum electric arc parameters. It was also shown that an organic solvent (N,N-dimethylformamide) is successfully used in selective extraction of M@C_2n. We identified the resulting products by mass spectrometry, electron spectrophotometry, EPR and X-ray fluorescence spectroscopy. The resulting N,N-dimethylformamide extracts of La@C_2n and Y@C_2n are shown to be free of empty fullerenes and appear as a mixture of endometallofullerenes M@C_2n whose main ingredient is M@C₈₂ (∼80 wt%). Transport properties of the extracts of La@C₈₂ and Y@C₈₂ were studied using pressed pellets. It was found that oxygen and heat treatment affect conductivity of endometallofullerenes. Heat treatment results in a three-order increase of conductivity from 10⁻⁵ upto 10⁻² Ohm⁻¹ cm⁻¹     

基于蚁群的Ad Hoc网络多路径路由的改进

在大规模的Ad Hoc网络中,带宽有限,并且节点移动会引起链路频繁中断,从而导致传输时延较大。针对这些缺点,文中提出了加入了链路失效预测的蚁群多路径路由算法LA-ACO （ Location Aided ACO）。通过蚁群算法的分布式计算来寻找多条路由,并利用多路径路由来进行数据包的负载平衡,同时进行链路失效的预测,利用蚁群的正反馈机制完成快速主动路由修复。在仿真得到的结果中可以发现,该算法有较好的寻优能力,并且适应于Ad Hoc网络的拓扑多变化的特性。     

基于消息的Parlay X网关过载控制算法

为了解决目前Parlay X网关过载算法灵活性低、不能有效地使会话量最大化的问题,给出了基于合约的Parlay X网关系统架构。根据Parlay X消息类型特点设置消息优先级,根据消息优先级选择丢弃或者缓存消息,之后根据负载情况进行负载均衡以及接入控制,通过四个阶段来实现过载控制过程。实验结果表明,相比较于传统过载控制,该机制能在保证新建会话消息接收数量的同时提高其他类型消息的接收数量,减少平均服务时间,在满足合约限制的情况下,保证最大会话数量。     

电力负荷管理终端常见现场故障分析

介绍终端系统的组成及电力负荷管理终端在其中起到的作用,分析终端现场运行故障的原因,并提出相应的处理措施。