A mixed pseudo-orthogonal frequency coding (Mixed-POFC) structure is proposed as a new spreadspectrum technique in this paper, which employs frequency and time diversity to enhance tag properties and balances the spectrum utilization and code diversity. The coding method of SAW RFID tags in this paper uses Mixed-POFC with multi-track chip arrangements. The cross-correlation and auto correlation of Mixed-POFC and POFC are calculated to demonstrate the reduced overlap between the adjacent center frequencies with the Mixed-POFC method. The center frequency of the IDT and Bragg reflectors is calculated by a coupling of modes (COM) module. The combination of the calculation results of the Bragg reflectors shows that compared with a 7-chip POFC, the coding number of a 7-chip Mixed-POFC is increased from 120 to 144 with the same fractional bandwidth of 12%. To demonstrate the validity of Mixed-POFC, finite element analysis (FEA) technology is used to analyze the frequency characteristics of Mixed-POFC chips. The maximum error between designed frequencies and simulation frequencies is only 1.7%, which verifies that the Mixed-POFC method is feasible.
The three-dimensional (3D) coordinate measurement of radio frequency identification (RFID) multi-tag
networks is one of the important issues in the field of RFID, which affects the reading performance of
RFID multi-tag networks. In this paper, a novel method for 3D coordinate measurement of RFID multitag
networks is proposed. A dual-CCD system (vertical and horizontal cameras) is used to obtain images of
RFID multi-tag networks from different angles. The iterative threshold segmentation and the morphological
filtering method are used to process the images. The template matching method is respectively used to
determine the two-dimensional (2D) coordinate and the vertical coordinate of each tag. After that, the
3D coordinate of each tag is obtained. Finally, a back-propagation (BP) neural network is used to model
the nonlinear relationship between the RFID multi-tag network and the corresponding reading distance.
The BP neural network can predict the reading distances of unknown tag groups and find out the optimal
distribution structure of the tag groups corresponding to the maximum reading distance. In the future work,
the corresponding in-depth research on the neural network to adjust the distribution of tags will be done.
Bread wheat is a major food crop on a global scale. Stripe rust, caused by Puccinia striiformis f. sp. tritici, has become one of the largest biotic stresses and limitations for wheat production in the 21st century. Post 2000 races of the pathogen are more virulent and able to overcome the defense of previously resistant cultivars. Despite the availability of effective fungicides, genetic resistance is the most economical, effective, and environmentally friendly way to control the disease. There are two major types of resistance to stripe rust: all-stage seedling resistance (ASR) and adult-plant resistance (APR). Although both resistance types have negative and positive attributes, ASR generally is race-specific and frequently is defeated by new races, while APR has been shown to be race non-specific and durable over time. Finding genes with high levels of APR has been a major goal for wheat improvement over the past few decades. Recent advancements in molecular mapping and sequencing technologies provide a valuable framework for the discovery and validation of new sources of resistance. Here we report the discovery of a precise molecular marker for a highly durable type of APR – high-temperature adult-plant (HTAP) resistance locus in the wheat cultivar Louise. Using a Louise × Penawawa mapping population, coupled with data from survey sequences of the wheat genome, linkage mapping, and synteny analysis techniques, we developed an amplified polymorphic sequence (CAPS) marker LPHTAP2B on the short arm of wheat chromosome 2B, which cosegregates with the resistant phenotype. LPHTAP2B accounted for 62 and 58% of phenotypic variance of disease severity and infection type data, respectively. Although cloning of the LPHTAP2B region is needed to further understand its role in durable resistance, this marker will greatly facilitate incorporation of the HTAP gene into new wheat cultivars with durable resistance to stripe rust.
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