基于网络融合下的电信产业价值链趋势分析

网络融合正改变着传统的电信产业价值链,3G时代的到来,更是对传统的产业价值链产生着深远的影响。在传统产业价值链的基础上,通过分析总结出了网络融合下的产业价值链模型,并得出了网络融合下电信产业价值链的发展趋势。     

Implementation and performance evaluation of a scheduling algorithm for divisible load parallel applications in a cloud computing environment

Cloud computing is an emerging technology in which information technology resources are virtualized to users in a set of computing resources on a pay‐per‐use basis. It is seen as an effective infrastructure for high performance applications. Divisible load applications occur in many scientific and engineering applications. However, dividing an application and deploying it in a cloud computing environment face challenges to obtain an optimal performance due to the overheads introduced by the cloud virtualization and the supporting cloud middleware. Therefore, we provide results of series of extensive experiments in scheduling divisible load application in a Cloud environment to decrease the overall application execution time considering the cloud networking and computing capacities presented to the application's user. We experiment with real applications within the Amazon cloud computing environment. Our extensive experiments analyze the reasons of the discrepancies between a theoretical model and the reality and propose adequate solutions. These discrepancies are due to three factors: the network behavior, the application behavior and the cloud computing virtualization. Our results show that applying the algorithm result in a maximum ratio of 1.41 of the measured normalized makespan versus the ideal makespan for application in which the communication to computation ratio is big. They show that the algorithm is effective for those applications in a heterogeneous setting reaching a ratio of 1.28 for large data sets. For application following the ensemble clustering model in which the computation to communication ratio is big and variable, we obtained a maximum ratio of 4.7 for large data set and a ratio of 2.11 for small data set. Applying the algorithm also results in an important speedup. These results are revealing for the type of applications we consider under experiments. The experiments also reveal the impact of the choice of the platforms provided by Amazon on the performance of the applications under study. Considering the emergence of cloud computing for high performance applications, the results in this paper can be widely adopted by cloud computing developers. Copyright © 2014 John Wiley & Sons, Ltd.     

The roles of user motivation to perform a task and decision support system (DSS) effectiveness and efficiency in DSS use

The purposes of this study are to: (1) obtain measures of actual decision support system (DSS) use that include the three elements of DSS use proposed by Burton-Jones and Straub (Burton-Jones, A., & Straub, D.W., Jr., (2006). Reconceptualizing system usage: An approach and empirical test. Information Systems Research, 17(3), 228–246), and (2) identify an important psychological construct – a user’s motivation to perform a task – and examine how it interacts with two DSS characteristics – effectiveness and efficiency – to affect actual DSS use. As predicted, the findings indicated that individuals who used a more effective DSS to work on a task that they were motivated in increased usage of the DSS, while DSS use did not differ between individuals who used either a more or less effective DSS to complete a task that they were less motivated in. The results also showed significant difference for two measures of DSS use (i.e., STEP and TIME) and no significant difference for one measure of DSS use (i.e., USE) between individuals who used either a more or less efficient DSS to perform a task that they were more motivated in. As expected, significant differences were found for individuals who used either a more or less efficient DSS to complete a task that they were less motivated in. Finally, the results showed that DSS use increased when perceived ease of use and perceived usefulness of the DSS were high; therefore, these results corroborate the findings of prior research in the context of actual DSS use.     

0.4%氯菊酯·氯氰菊酯水乳剂的液相色谱分析

介绍了用高效液相色谱法,采用Hypersil SiO2色谱柱,以异辛烷+1,4-二氧六环为流动相,在230nm下检测,外标法定量分析氯菊酯和氯氰菊酯的方法.方法的标准偏差分别为0.0084和0.0084,变异系数分别为4.0%和3.8%,回收率分别为99.31%～100.36%和98.32%～100.09%.     

喷射成形GCr15钢的实验研究

应用喷射成形技术制备了GCr15钢沉积坯,同时收集了过喷粉末.采用金相显微镜、扫描电镜等对二者进行了研究.结果表明,过喷粉末大部分呈规则球形,但也有一些呈特殊形态.沉积坯中有些部位存在孔隙,等轴晶为其特征组织,晶粒大小分布具有一定规律.     

Microstructures and Properties of SiC／Al2O3 ／Al- Si Composites Prepared by Reactive Penetration

The composition, microstructures and properties of SiC/Al2O3/Al-Si composites formed by reactive penetration of the molten aluminum into the preforms of SiO2 and SiC were investigated. The composition of the composites was measured by X-ray diffraction ( XRD ). The microstructures of the composites were also measured by scanning electron microscopy (SEM) and optical microscopy. In addition, the factors affecting the properties of the composites were discussed. The experiments show that the mechanical properties of the composites depend on their relative densities and the sizes of the fillers“ SiC gains“. The denser the SiC/Al2O3/Al-Si composites, the higher their bending strength. As the filler “SiC gains“ become fine, the bending strength of the composites increases.     

硝酸铍硝酸淋洗液离子色谱法测定碱土金属离子

本文提出一种新颖的用于碱土金属离子色谱法测定的淋洗液——硝酸铍—硝酸溶液。该淋洗液与抑制电导检测方式相结合具有使分离效果好、检测灵敏度高和抑制柱容易再生的优点,是目前碱土金属离子色谱法较为理想的淋洗液。     

玻璃加工质量对有源光纤芯包界面缺陷的影响

通过片状玻璃模拟光纤拉丝情况并采用正交试验法设计实验，研究了掺稀土磷酸盐玻璃光纤纤芯与包层界面在不同光学加工质量下的微观缺陷：研究表明良好的预制棒加工质量可有效改善光纤纤芯与包层的界面状态，并且相对于纤芯玻璃来说，粘度较高的包层玻璃其加工质量对界面缺陷的影响更为显著。在此研究基础上提出了获得良好界面状态的光学加工条件。     

工程施工合同的签订和履行中应注意的问题

阐述了在当前市场经济体制尚不完善的条件下，应在工程施工合同的签订和履行方面需要着重注意的问题，以取得工程施工项目经济效益的最大化。     

中国光纤光缆产业的发展趋势探讨

本文通过回顾我国光纤光缆产业的关键技术和产业构成,分析总结产业发展取得的成果和存在的不足,提出了我国光纤光缆产业下一步发展的五个方向的思考,供同行们参考。