A method for throughput enhancement in Wi-Fi backscatter communications using power-level modulation

An improved data rate technology from tag to reader in Wi-Fi backscatter systems is proposed. The proposed system applies a power-level modulation to the conventional backscatter communication system. This technology can improve the data rate dramatically. It also adopts the Euclidean distance evaluation during demodulation, which looks for the most similar signal to enhance the BER performance. We analyze the error performance of the proposed decoding method, and the numerical results are presented. The power level is formed ranging from 2-level to 8-level. The performance of the detecting algorithm is compared to the conventional system, which utilizes the received power of selected sub-carriers.     

ERSA Conference participation: does location matter?

Abstract.  This article analyses participation in the annual European congresses of the Regional Science Association (ERSA) from 1998 through 2003. We formulate goals that the ERSA conferences should aim at and based on these aims we formulate hypotheses about conference participation. In the empirical part we test hypotheses with regard to the spatial distribution of the participants over countries, the distribution of the frequency of attendance among the participants, and the presence of distance decay in participation. All hypotheses are confirmed. We also pay attention to the relation between the frequency of attendance and distance. In the conclusions we derive implications for future conferences.     

改性CaTi_(0.9)Li_(0.1)O_3上乙烷催化氧化脱氢制乙烯的研究

ＣａＴｉ０９Ｌｉ０１Ｏ３催化剂中添加ＣｅＯ２、Ｌａ２Ｏ３、Ｙ２Ｏ３、ＮｉＯ等金属氧化物可不同程度地改进催化剂性能,其中以ＮｉＯ／ＣａＴｉ０９Ｌｉ０１Ｏ３催化剂性能最佳,乙烯收率在７７５℃比ＣａＴｉ０９Ｌｉ０１Ｏ３作催化剂提高１２２％,适当控制反应条件,可使７７５℃的乙烷转化率达５５２％,乙烯选择性为７３％。ＮｉＯ／ＣａＴｉ０９Ｌｉ０１Ｏ３催化剂的最佳ＮｉＯ含量为３０％,最佳焙烧温度为８００℃,催化剂上乙烷氧化脱氢适宜的反应条件为,反应温度７７５～８００℃,Ｖ（Ｃ２Ｈ６）／Ｖ（Ｏ２）＝１７～２,原料气空速为（２～３）×１０４ｈ－１,原料气中惰性气体含量为２０％～５０％。     

COMPLEX AND REAL PERFORMANCE RADII AND THEIR COMPUTATION

This paper considers the problem of robust performance of a linear time-invariant system in the ℋ︁_∞ norm. The concepts of complex and real performance radii are introduced to describe the smallest size of dynamic or parametric perturbations to a feedback system that either destabilize the system or destroy a performance bound in a certain closed-loop transfer matrix of the system. An algorithm to compute the complex performance radius is given. For the real performance radius, a lower bound, which often turns out to be exact, is obtained. © 1997 by John Wiley & Sons, Ltd.     

Sr复合变质剂对Al-Si合金变质影响的研究（续）

运用正交试验研究Al-10%Sr变质剂对G01铝合金的变质工艺,研究不同的变质剂添加量、变质温度、变质时间对变质效果的影响,探索Sr变质剂在Al-Si合金生产中的工艺方法。     

一种工业无线遥控系统设计

应用MSP430f1232和NRF24L01集成电路设计了一种工业无线遥控系统。介绍了该系统的硬件组成结构和软件实现流程,给出了部分实现程序。经过试验表明,该遥控系统可通过手持端指示灯动态获取接收端工作状态,可以提高工业场合远距离作业时的安全性,适用于单钩、单速电动葫芦或葫芦式桥式起重机。系统结构简单,经过改进也可用于其他设备的控制。     

Back to the Future

Paul Preissner provides a typological prototype for the protocell, the Protocell Tower. Does it, however, already look familiar? Though a breathtaking chemical innovation, could protocell technology actually be behind the curve of architecture? Could it be that architects have already been playing with the aesthetics of this unrealised matter for the last 15 years? Preissner suggests some urban approaches that might enable us to use protocells to rejuvenate existing architecture. Copyright © 2011 John Wiley & Sons, Ltd.