An improved anti‐collision protocol for radio frequency identification tag

Many anti‐collision protocols have been proposed at present. Almost all known protocols exhibit an overall identification efficiency smaller than 50%. And all of them are proposed for general purpose applications and do not consider the distribution characteristic of tag IDs in different radio frequency identification (RFID) systems. In real world, there are many RFID systems, in which the tag IDs are mostly distributed continuously, such as in container terminals, warehouse management, supply chain management, and so on. This paper presents an efficient anti‐collision protocol, named improved collision tree protocol (ICT), to identify RFID tags simultaneously. The main novelties of this paper include that the duality and certainty principle is introduced and used in ICT to improve the tag identification efficiency, and the continuous and partially continuous distributions of tag IDs are taken into account in this paper. Both the theoretical and experimental results indicate that ICT improves the tag identification efficiency up to 100% when the tag IDs are distributed continuously, and always above 50% even when the tag IDs are distributed uniformly. For straightforward and efficient, ICT can be used in various RFID tag identification conditions, especially when the tag IDs are distributed continuously or partially continuously. Copyright © 2013 John Wiley & Sons, Ltd.     

Numerical analysis and passive control of a car side window buffeting noise based on Scale-Adaptive Simulation

Flow over an open side window in a car exhibits similar characteristics as the flow over an open cavity. Computational Fluid Dynamics (CFD) simulation over a cavity was done as a benchmark. The unsteady flow simulation was carried out using Scale Adaptive Simulation (SAS) turbulence model. The benchmark results, frequency and sound pressure levels of feedback and resonance modes, all well matched with the experimental data. Then, with the right rear window, for example, the mechanism of the side window buffeting was investigated. The simulation results show that side window buffeting noise is generated by large scale vortices and in low frequency. Furthermore, buffeting noise characteristics under several patterns of side windows opening were also numerically investigated. As a result, rear window buffeting noise is more severe than that of front window when one window open, and combination pattern of side windows open can reduce buffeting noise. To decrease the interior noise and improve car ride comfort, four suppression measures through adding a side window weather deflector at the A-pillars, constructing a cavity at the B-pillars, combination of the front and rear windows and installing a row of square cylinder deflector at the B-pillars were also studied, respectively. In conclusion, certain noise reduction can be achieved through four passive control methods.     

声表面波射频识别技术应用与发展

声表面波(SAW)射频识别(RFID)技术是当前信息识别系统向无源无线发展的关键技术,在工业、国防及商业等领域有重要作用和广泛应用前景。该文探讨了SAW RFID技术原理及信息编码方案;综述了典型的SAW RFID产品及应用;提出了SAW RFID技术发展趋势,对推动SAW RFID技术发展和应用有重要意义。     

射频识别技术理论及其在物流领域的应用研究

射频识别技术在我国应用的越来越广泛,其可以使物流信息和资料的采集更加迅速、精准,并且能够实时了解物品运输动态。为了达到促进射频识别技术在物流领域的科学合理的应用,更好地保障物流质量水平的目的,采用先通过对射频识别技术的理论进行介绍,再对其在物流领域的应用进行阐述,并分析其中存在的问题。研究出解决的途径和方法。     

QinQ技术在广电IP数据网中的应用与实践

随着广电运营业务发展迅速,城域网上的业务种类繁多,城域网面临着资源耗尽、传输效率低、受攻击出现大面积故障等问题。介绍利用QinQ技术的特性,将QinQ技术成功部署于宽带网络上,实践证明,QinQ技术可有效提升广电宽带网络的稳定性与可维护性。     

Vibration control for adjacent structures using local state information

In this paper, a novel strategy for structural vibration control of multi-structure systems is presented. This strategy pays particular attention to mitigating negative interstructure interactions. Moreover, it is based on recent advances in static output–feedback control, which make possible the efficient computation of decentralized velocity-feedback controllers by solving a single-step optimization problem with Linear Matrix Inequality constraints. To illustrate the main ideas, a local velocity-feedback energy-to-peak controller is designed for the seismic protection of a two-building system. This controller is remarkably effective and extremely simple. Moreover, it can also be implemented by a linear passive damper. To assess the effectiveness of the proposed controller, numerical simulations are conducted with positive results.     

实用电子组装技术：电子组装中元器件的选择与应用（续完）

电子元器件的质量可靠性直接影响到产品整机可靠性。主要总结了常见无源元件及有源器件的分类、结构特点及应用领域。对元器件的选择和使用给出了经验指导,而且对其组装工艺进行了简要阐述。     

Secure and efficient lightweight RFID authentication protocol based on fast tag indexing

During the radio‐frequency identification authentication process, it is of great significance to quickly find out the target tag from all tags stored in the database, because it affects the authentication performance to a great extent. Most of the existing schemes use the Hash or pseudorandom number generator operation to locate the target tag, but if the number of tags is extremely large, vast Hash or pseudorandom number generator operations may take much time and lower the authentication efficiency. To locate the target tag quickly, the RAP and LADP protocols adopt the simple value comparison method, and the back‐end server can easily find the target tag by directly comparing the received index‐pseudonym value with those stored in the database. This method does improve the authentication performance, but it results that these schemes suffer from the tag tracking attack. Motivated by these concerns, we propose a novel tag indexing method called the two‐layer tag indexing mechanism, and at the same time, we give a lightweight radio‐frequency identification authentication protocol based on it. Analyses show that our scheme can effectively resist the tag tracking attack and is almost as efficient as the RAP and LADP protocols in indexing tags. Copyright © 2013 John Wiley & Sons, Ltd.     

Suppression of optical beat interference-noise in orthogonal frequency division multiple access-passive optical network link using self-homodyne balanced detection

A new technique, which reduces optical beat interference (OBI) noise in orthogonal frequency division multiple access-passive optical network (OFDMA-PON) links, is proposed. A self-homodyne balanced detection, which uses a single laser for the optical line terminal (OLT) as well as for the optical network unit (ONU), reduces OBI noise and also improves the signal to noise ratio (SNR) of the discrete multi-tone (DMT) signal. The proposed scheme is verified by transmitting quadrature phase shift keying (QPSK)-modulated DMT signal over a 20-km single mode fiber. The optical signal to noise ratio (OSNR), that is required for BER of 10⁻⁵, is reduced by 2 dB in the balanced detection compared with a single channel due to the cancellation of OBI noise in conjunction with the local laser.     

Network coding based joint signaling and dynamic bandwidth allocation scheme for inter optical network unit communication in passive optical networks

As an innovative and promising technology, network coding has been introduced to passive optical networks (PON) in recent years to support inter optical network unit (ONU) communication, yet the signaling process and dynamic bandwidth allocation (DBA) in PON with network coding (NC-PON) still need further study. Thus, we propose a joint signaling and DBA scheme for efficiently supporting differentiated services of inter ONU communication in NC-PON. In the proposed joint scheme, the signaling process lays the foundation to fulfill network coding in PON, and it can not only avoid the potential threat to downstream security in previous schemes but also be suitable for the proposed hybrid dynamic bandwidth allocation (HDBA) scheme. In HDBA, a DBA cycle is divided into two sub-cycles for applying different coding, scheduling and bandwidth allocation strategies to differentiated classes of services. Besides, as network traffic load varies, the entire upstream transmission window for all REPORT messages slides accordingly, leaving the transmission time of one or two sub-cycles to overlap with the bandwidth allocation calculation time at the optical line terminal (the OLT), so that the upstream idle time can be efficiently eliminated. Performance evaluation results validate that compared with the existing two DBA algorithms deployed in NC-PON, HDBA demonstrates the best quality of service (QoS) support in terms of delay for all classes of services, especially guarantees the end-to-end delay bound of high class services. Specifically, HDBA can eliminate queuing delay and scheduling delay of high class services, reduce those of lower class services by at least 20%, and reduce the average end-to-end delay of all services over 50%. Moreover, HDBA also achieves the maximum delay fairness between coded and uncoded lower class services, and medium delay fairness for high class services.