基于RFID和GRNN的景区人流量预测GIS的研究与设计

在分析无线射频识别(RFID)原理和广义回归神经网络(GRNN)模型的基础上,探讨了基于RFID的人流量统计方法,并重点研究了景区人流量短时预测方法,最后从实际应用出发建立了可对景区人流量进行实时预测的GIS决策系统。     

Field tests of an improved sediment tracer including non-intrusive measurement of burial depth

Radio-frequency identification (RFID) transponders are now widely used to track sediment in a variety of environments. A recent innovation placed the transponder inside of a rotating inner mechanism that is designed to minimize missed detections due to burial and shielding or ‘signal collision’ effects between tracers, while also allowing a rapid measurement of the burial depth of the particle. Here we test a developed protocol for burial depth measurement and deploy the ‘Wobblestone’ tracers in the field for the first time. Results show that new tracers can be reliably positioned in the horizontal plane (median error ± 0.03 m) and that the burial depth can be accurately measured (~0.02 m maximum error). The field study was characterized by high mobility and travel lengths, and ~20% of the tracers were buried at depths up to 0.15 m. A comparison of exponential distributions for travel length of surface deposited and buried tracers indicate that the buried tracers on average traveled farther and earlier in the flood event. Tracers that did not move were also buried at one site as a result of sediment transport from upstream. Overall the technique has great potential for characterizing vertical mixing and understanding this rarely considered control on sediment transport. © 2020 John Wiley & Sons, Ltd.     

Erosion,transport and deposition of a sediment replenishment under flood conditions

River reaches downstream of dams with constant residual discharge often lack sediment supply and periodic high flows due to dam sediment retention and flow regulation, respectively. To test a novel multi-deposit methodology for defining environmental flows for activating the dynamics of the river morphology downstream of dams, a flood was released from Rossens Dam in Switzerland. This event was combined for the first time with a multi-deposit configuration of sediment replenishment consisting of four artificial deposits allocated as alternate bars along the riverbanks as a restoration measure. To validate the sediment transport behaviour observed in laboratory tests, stones were equipped with radiofrequency identification (RFID) passive integrated transponder (PIT) tags, a fixed antenna was installed at the river bed and a mobile antenna was used to enable the investigation of the erosion, transport and deposition of replenished sediments. The duration of the erosion period was determined for the tracked stones, and average transport velocities were found to be on the order of 10^–3 m/s. To estimate the erosion efficiency of the flood, defined as the eroded tagged stones compared with the released water volume, the hydrograph was divided into different periods: rising limb, constant peak discharge, decreasing limb. During the rising limb of the flood, which lasted for 20% of the total flood duration, more than 40% of the PIT tags were transported. The defined erosion efficiency is a measure to support the hydrographic design of artificial flood releases from dams. The deposition of tagged stones resulted in a repeating cluster formation, as expected from previous laboratory experiments, creating an increase in hydraulic habitat diversity. Comparison of the results obtained in the field and from laboratory experiments confirmed the robustness of the multi-deposit sediment replenishment method. Combined with the knowledge gained on the erosion efficiency, these results could motivate further applications and research into multi-deposit sediment replenishment techniques as a habitat-oriented river restoration measure. © 2020 John Wiley & Sons, Ltd.     

Effects of transport and insertion of radio frequency identification (RFID) transponders on resistance and shape of natural and synthetic pebbles: applications for riverine and coastal bedload tracking

RFID transponders, especially low‐frequency Passive Integrated Transponders (PIT tags), are now commonly used for assessing bedload mobility in gravel‐bed rivers. Early studies reported high PIT tag recovery rates in small streams, but recovery rates in larger systems remain low. Explanatory factors for low recovery rates have been identified, but only antenna detection ranges and clustering effects have been precisely characterized. Burial below detection limit and dispersion beyond the study site have been indirectly estimated, and PIT tag destruction is assumed to be negligible. In this study, we quantified the resistance of natural limestone pebbles equipped with PIT tags as related to tag insertion methods and distance travelled in an annular flume. We then compared the performance of these natural pebbles with synthetic pebbles made of polyurethane resin and corundum. Creation of synthetic pebbles makes it possible to test bigger transponders with a greater detection range and no clustering effects, bypassing the existing constraints of RFID tracking. We found that breakage of limestone particles leading to PIT tag destruction is far too rare to explain low recovery rates in situ. Further, breakage is more affected by initial pebble characteristics than by PIT tag insertion method. Synthetic pebbles are more sensitive to attrition, but less likely to break. Natural and synthetic pebbles show slight differences in mobility patterns, transport distances, and abrasion resistances. One of the two synthetic pebbles travelled faster than the other three indicating that mobility is not only related to density but also potentially to shape. To address clustering and detection range issues, we equipped synthetic pebbles with AIT‐tags (Active Integrated Transponders). These were tested for integrity and transponder endurance and show great promise for future applications. Copyright © 2016 John Wiley & Sons, Ltd.     

基于GPS和RFID的城市车辆定位系统的设计

详细阐述了城市车辆导航定位技术的发展现状,深入分析了城市车辆导航定位的特点和需求,在此基础上利用嵌入式开发平台设计实现了基于GPS和RFID(无线射频识别)的车载定位系统,系统主要由GPS模块、RFID模块、GPRS(general packet radio service,通用分组无线服务)模块等部分组成。该系统通过接收GPS数据和RFID数据,依托ARM平台进行分析处理,分析处理的结果通过GPRS模块发送到监控中心以实现对车辆的监控与导航。该系统具有实时性好、可靠性高、功耗体积小等显著特点,能够满足现代城市车辆的导航与定位需要。     

一种基于射频识别的气象探测装备动态信息管理平台设计

为不断提高气象探测装备保障业务的科技含量与信息化水平,亟待建立高效及时的相关管理平台。本文结合北京市气象装备管理的实际情况和业务需求,设计了一种基于射频识别(Radio Frequency Identification,RFID)的气象探测装备动态信息管理平台,对平台结构设计进行相关阐述,重点分析了平台基于RFID技术的信息传输以及详细功能,并针对平台建设提出一些思考与展望。     

Intertidal boulder transport: A proposed methodology adopting Radio Frequency Identification (RFID) technology to quantify storm induced boulder mobility

Boulder transport is an area of growing interest to coastal scientists as a means of improving our understanding of the complex interactions between extreme wave activity and the evolution of rocky coasts. However, our knowledge of the response of intertidal boulder deposits to contemporary storm events remains limited due to a lack of quantifiable field-based evidence. We address this by presenting a methodology incorporating Radio Frequency Identification (RFID) tagging and Differential Global Positioning Navigation Satellite System (DGNSS) technology to monitor and accurately quantify the displacement of RFID tagged boulders resulting from storm wave activity. Based on preliminary findings we highlight the suitability of the technology and methodology to better understand the spatial and temporal response of intertidal boulders to contemporary storm events. We inserted RFID tags in 104 limestone boulders (intermediate axes from 0.27 to 2.85 m) across a range of morphogenic settings at two sites on the intertidal shore platforms at Bembridge, Isle of Wight (UK). Fifteen topographic surveys were conducted between July 2015 and May 2017 to relocate and record tagged boulder locations (tag recovery rate: 91%). The relocated boulder coordinate data from both sites identified 164 individual transport events in 63% of the tagged boulder array amounting to 184.6 m of transport, including the displacement of a boulder weighing more than 10 tonnes. Incidents of boulder quarrying and overturning during transport were also recorded, demonstrating that despite the relatively sheltered location, intertidal boulders are created and regularly transported under moderate storm conditions. This suggests that contemporary storm events have a greater propensity to mobilise boulders in the intertidal range than has previously been realised. Consequently, by documenting our methodology we provide guidance to others and promote further use of RFID technology to enable new hypotheses on boulder transport to be tested in a range of field settings and wave regimes. © 2018 John Wiley & Sons, Ltd.     

TIN-based Tag Map Layout

With the widespread use of tag clouds, multiple map-based variations have been proposed. Like standard tag clouds (also called word clouds), these ‘tag maps’ all share the basic strategy of displaying words within a ‘geographic space’ and scaling the word size to depict frequency (or importance) of those words within some dataset. While some tag maps simply plot a standard tag cloud on top of a map, the subset of tag maps we focus on here are those in which the collection of words are displayed within bounded geographic regions (often of irregular shape) that the words are relevant for. For this form of tag map, map scale and polygon shape add constraints to word size and position that have not been considered in most prior approaches to tag map word layout. In this paper, we present a layout strategy for tag map generation that includes consideration of the shape and size of the geographical regions acting as containers for the tags. The method introduced here uses a triangulated irregular network (TIN) to subdivide the geographical region into many triangle subareas, with the centroid of each triangle being a potential location to centre a tag on. All the triangles are sorted by their area and all the tags are sorted by their weight value (e.g. frequency, importance or popularity). Positioning of tags is undertaken sequentially from most important (or frequent or popular) with potential locations being the TIN triangle centroids (tried from largest to smallest triangle). After each tag placement, the TIN is recalculated to integrate the tag centroid and bounding corners into the TIN creation. The limited whitespace in the geographical region, at any specific scale, is used fully by dynamically adjusting the font size along with the number and the direction of tags. The method can be applied to add tags within geographic polygons that are convex, concave and other more complex regions containing holes or islands.     

基于GIS/GPS/GPRS的物流车辆监控系统

论文介绍了目前物流车辆监控系统涉及到的主要技术,地理信息系统(GIS),全球定位系统(GPS)和通用无线分组业务(GPRS)。系统由GPS通讯服务系统、物流子系统、GIS子系统、综合监控系统4个子系统组成。文章对系统的原理和各个子系统的功能进行了详细的描述,并对GPS通讯服务程序的解析过程进行了分析,系统的使用和研究将加速GIS在物流和商业中的应用。     

Detection ranges and uncertainty of passive Radio Frequency Identification (RFID) transponders for sediment tracking in gravel rivers and coastal environments

Since the earliest use of this technology, a growing number of researchers have employed passive Radio Frequency Identification (RFID) transponders to track sediment transport in gravel rivers and coastal environments. RFID transponders are advantageous because they are inexpensive, durable and use unique codes that allow sediment particle mobility and displacement to be assessed on a clast‐by‐clast basis. Despite these advantages, this technology is in need of a rigorous error and detection analysis. Many studies work with a precision of ~1 m, which is insufficient for some applications, and signal shadowing can occur due to clustering of tagged particles. Information on in‐field performance is also incomplete with respect to burial and submergence, especially for different transponders and antennae combinations. The objectives of this study are to qualify and quantify the factors that influence the detection zone of RFID tracers including antenna type, transponder size, transponder orientation, burial depth, submergence and clustering. Results of this study show that the detection zone is complex in shape due to a set of lobes in the detection field and provide a better understanding of transponder detection shape for different RFID transponder/antenna combinations. This study highlights a strong influence of clustering and submergence, but no significant effect of burial. Finally we propose standard operating procedures for tagging and tracking in rivers and coastal environments. Copyright © 2014 John Wiley & Sons, Ltd.