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关键词： Bombus   bumble bee   foraging   foundress   queen   RFID   survival  

摘要： The overwhelming majority of research on wild bumble bees has focused on the social colony stage. Nest-founding queens in the early season are difficult to study because incipient nests are challenging to find in the wild and the foundress queen flight period is very short relative to the entire nesting period. As a result, natural history information on foundress queens is exceedingly rare. New methodological approaches are needed to adequately study this elusive life stage. We trap-nested wild queen bumble bees in artificial nest boxes in Gothic, Colorado and used a custom-built radio frequency identification (RFID) system to continuously record queen foraging activity (inferred from entering and exiting the nest) for the majority of their spring flight periods. Foundress queens made frequent, short foraging trips, which tended to increase in duration over the course of the flight period. All queens who produced adult workers ceased foraging within approximately 1 week after workers emerged in the nest. We observed frequent nest failure among foundress queens: Fewer than one quarter of queens who laid eggs in nest boxes went on to produce reproductive gynes at the end of the season. We also report nest characteristics and curious phenomena we observed, including conspecific nest invasion and queens remaining outside the nest overnight. We present this trap-nesting and subsequent RFID tracking method as a valuable, albeit resource-intensive, path forward for uncovering new information about the elusive, incipient life stage of wild bumble bees.

关键词： 5G   backscatter communication   Bluetooth   error correction coding   RFID   ubiquitous radio sources   WIFI   Zigbee  

摘要： Traditional RFID systems rely on dedicated readers, often expensive and bulky, hindering their widespread deployment. This paper proposes an alternative RFID system that leverages ubiquitous radio sources-Wi-Fi, 5G, Bluetooth, and Zigbee-to replace dedicated readers. Our system employs backscatter communication, where RFID tags modulate reflected signals from these readily available sources to transmit data. We investigate the feasibility and performance of this approach through Matlab simulator. Our results show that 802.11ax at 2.45 GHz exhibits the best symbol error rate, followed by 802.11n at the same frequency. However, 5G, Bluetooth, and Zigbee signals demonstrate lower performance even at high signal-to-noise ratios. To address this, we introduce error correction coding techniques (BCH and RS) that significantly improve communication reliability. Utilizing these codes, our system achieves a communication range of up to 1 m. This finding highlights the potential of ubiquitous radio sources as a viable alternative to dedicated RFID readers, opening doors for various applications.

关键词： Downhole tool   RFID   Transmission model   FSK   Signal attenuation  

摘要： Radio frequency identification (RFID) technology is a new type of intelligent drilling and completion technology that can be used for remote control of downhole tools. In RF modulation, frequency shift keying (FSK) has stronger anti-interference ability compared to amplitude shift keying (ASK), but its transmission characteristics for downhole RF signal are not yet clear, which cannot provide theoretical support for designing downhole RFID systems. In this paper, a transmission model for downhole wireless RF signals based on FSK modulation is established by combining Maxwell's equations, Biot-Savart's law, and the proposed model was verified through the simulation results and the experimental results, and the influence of the excitation intensity, the transmission distance, and the conductivity of drilling fluid on transmission attenuation was deeply studied. This study highlights the influence of conductivity on drilling or completion fluids by integrating 2FSK modulation, excitation, propagation, and induction reception of downhole electromagnetic waves into the proposed model. The mathematical model proposed in this study has been proven to predict transmission characteristic values close to experimental results with an average accuracy of over 90%. The results show that the excitation voltage, the transmission distance and conductivity of drilling and completion fluids have a significant impact on the propagation and reception of downhole RF signals. These analysis results can provide effective guidance and inspiration for the design and application of digital drilling and completion instruments.

关键词： Animal behaviour   Gambit of the group   Sociality   Social network   RFID  

摘要： The interconnecting links between individuals in an animal social network are often defined by discrete, directed behaviours, but where these are difficult to observe, a network link (edge) may instead be defined by individuals sharing a space at the same time, which can then be used to infer a social association. The method by which these associations are defined should be informed by the biological significance of edges, and therefore often vary between studies. Identifying an appropriate measure of association remains a challenge to behavioural ecologists. Here, we use automatically recorded feeder visit data from four bird systems to compare three methods to identify a social association: (1) strict time-window, (2) co-occurrence in a group, and (3) arrival-time. We tested the similarity of the resulting networks by comparing the repeatability and sensitivity of individuals' social traits (network degree, strength, betweenness). We found that networks constructed using different methods but applying similar, ecologically relevant definitions of associations based on individuals' spatio-temporal co-occurrence, showed similar characteristics. Our findings suggest that the different methods to construct animal social networks are comparable, but result in subtle differences driven by species biology and feeder design. We urge researchers to carefully evaluate the ecological context of their study systems when making methodological decisions. Specifically, researchers in ecology and evolution should carefully consider the biological relevance of an edge in animal social networks, and the implications of adopting different definitions.

关键词： RFID   Anti-collision   Avoidance   Recovery   MAC layer   Physical layer  

摘要： By adopting appropriate anti-collision strategies, radio frequency identification (RFID) technology can realize fast and contactless reading of multiple tags, significantly improving identification efficiency and accuracy. Traditional anti-collision strategies commonly employ a collision avoidance policy that operates at the MAC layer. The principle of this strategy involves coordinating communication between multiple tags and readers through a series of algorithms. However, in large-scale and intensive scenarios, an increased likelihood of signal collisions occurs within the system due to the growing number of tags, and the traditional strategy fails to adapt to these scenarios. To further address the collision problem in RFID systems in severe environments, researchers have proposed collision recovery-based anti-collision strategies. This strategy leverages the physical layer characteristics of RFID signals, aiming to resolve the collision issue in the system through signal recovery or parallel decoding. In this work, we initially discuss the collision problem in RFID systems. Subsequently, a review of recent works based on collision avoidance strategies is presented and synthesized. After that, we review anti-collision strategies based on collision recovery, classifying and analyzing collision recovery schemes from various perspectives. Ultimately, we provide an outlook of future research directions for this technology.

关键词： 射频识别   近场天线   磁场均匀  

摘要： 设计了一种多环形结构超高频射频识别（RFID）阅读器近场天线。天线整体结构呈圆形，由8个扇形辐射贴片旋转分布组成，通过扇形辐射贴片间的紧耦合和加载寄生弧形贴片，实现了天线表面电流旋向相同，能够在识别区域内产生较为均匀的磁场和多极化的电场。天线直径为130mm，印制在厚度为1.6mm的FR-4介质基板上，实测结果表明，端口反射系数|S11|<-10dB的频带宽度为904～932MHz，在天线上方直径为130mm的圆形区域内可产生较均匀的磁场。采用Impinj E710阅读器进行标签测试，在30dBm功率输出下，磁耦合环形标签J41的最远100%读取距离为16cm；本文天线能产生多极化电场，对于不同方向摆放的电极化标签具备相近的读取能力。

关键词： Breast cancer   Non-palpable breast lesions   Radio-frequency tag   Wire-guided-localization   Breast conservation surgery  

摘要： Background Most breast cancers are detected at an early stage in which case conservative surgery is indicated. An accurate preoperative localization technique is essential for conservative surgery of non-palpable breast lesions. Currently, the gold standard technique is wire localization (WL). However, this technique has well-known drawbacks. Several wire-free techniques have been developed to overcome these drawbacks;one technique is localisation by Radiofrequency Identification (RFID). The purpose of this clinical trial was to assess the superiority of RFID tags (HOLOGIC) in terms of patient satisfaction, over wire localization of non-palpable breast lesions. Methods This was a single-centre, prospective, controlled and non-interventional trial. Patients were followed from their inclusion at the time of the preoperative consultation to the postoperative consultation, one month after surgery. Data on anxiety and satisfaction was collected from patients and clinicians using questionnaires, and clinical data was collected from the medical files. The primary outcome was the patients' satisfaction scores, assessed using a visual analogue scale. Results Eighty patients were sequentially enrolled in two groups: the wire group (n = 40) and the RFID group (n = 40). One patient from the RFID group was excluded from the analysis because of a substantial migration during deployment. On a 10-point Visual Analogue Scale, the patients' median satisfaction score was 9.8 (IQR = 1.32) for the wire group and 10 (IQR = 0.07) for the RFID group (p < 0.001). A reduction in pain between device insertion and surgery was observed in the RFID group (p = 0.009). The median placement time was shorter in the RFID group (15 min, IQR = 6) than in the wire group (20 min, IQR = 30) (p = 0.01). Conclusion Our results show a statistically significant difference in median patient satisfaction score with the localization of non-palpable breast cancer lesions using RFID tags compared to the use of the

关键词： RFID   Radiofrequency Identification   InventoryManagement   Hazardous Materials   Nuclear Inventory   Efficiency   Compliance  

摘要： Effective inventory management can be overshadowed by conflicting priorities in organizational procedures, particularly in research-focused institutions such as national laboratories that handle expensive, delicate, and hazardous materials. This study investigated the potential of radiofrequency identification (RFID) technology, currently used for hazardous chemical inventory, in applications with higher metal interference and absorption, specifically pressure release device (PRD) compliance and nuclear container management, at Lawrence Livermore National Laboratory (LLNL). This study was done to document best practices to enhance inventory identification speeds for inventory reconciliation and inventory recall and to explore optimal configurations for RFID implementation compared to traditional manual methods of equipment management. Tests were conducted to determine the ideal RFID tag orientation (read at angles of 0 degrees, 90 degrees, and 270 degrees), various container layouts (linear, separated, curved, operational), and ID methods such as manual, barcode, and RFID performing three trials per method per orientation. Results indicated that 0 degrees was the optimal read angle for minimizing metallic interference, and the operational and curved arrangements significantly outperformed the linear and separated configurations in read speed. 3D printed mounts were developed and tested, increasing the read range of the RFID reader by up to 235% in cases of high metallic interference. The RFID technology demonstrated an average speed increase of 65% over a simplified manual identification, which supports the conclusion that RFID is a more efficient method for large hazardous inventory management and equipment reconciliation. Additionally, capturing meta-data, such as location and date, can be used to query for inventory recall and automated updating of record information.

关键词： RFID室内定位   径向基函数神经网络   粒子群优化算法   无迹卡尔曼滤波  

摘要： 针对现有的多数RFID室内定位方法尚存在模型对环境的适用性问题及定位精度不高的问题，提出一种融合神经网络和非线性优化算法的改进RFID室内定位方法。首先，建立以对数路径损耗模型为基础的径向基函数(RBF)神经网络路径损耗系数预测模型，并基于粒子群优化(PSO)算法对网络的核心参数进行寻优，以增强模型对实际室内环境的适用性；其次，结合无迹卡尔曼滤波(UKF)对由最小二乘法估计出的待定位标签的初始坐标进行优化，以进一步提升模型的定位精度。实验结果表明，相比于其他同类方法，该方法在定位精度、定位速度及鲁棒性上表现更优，具有广阔的应用前景。