Ambient Monitoring System Research Articles

Hybridized Triboelectric-Electromagnetic Aeolian Vibration Generator as a Self-Powered System for Efficient Vibration Energy Harvesting and Vibration Online Monitoring of Transmission Lines.

In this work, based on the triboelectric-electromagnetic working principle, a comprehensive strategy appropriately hybridizes a multilayered elastic structure TENG (ME-TENG) and a double-electromagnetic generator (EMG) for efficient aeolian vibration energy harvesting and vibration state monitoring. The ME-TENG with the feature of elasticity is integrated with a movable plate embedded with a magnet as the counterweight, which acts as a spring-like mass system in response to external vibration excitation, making the inseparable integrity of the TENG and EMG. The basic hybridized triboelectric-electromagnetic aeolian vibration generator (HAVG) consisting of ME-TENG and double-EMGs in terms of structural parameters and response characteristics is first optimized and discussed, thereby the efficient vibration energy harvesting and effective vibration state response can be further improved through the mutual complementarity of TENG and EMG. Furthermore, the self-powered capacity of the HAVG in terms of LED arrays and a wireless ambient temperature and humidity monitoring system is verified through the hybrid charging strategy of TENG and EMG modules and the combination of HVAG and energy management circuits, benefiting from the sophisticated-designed structure and excellent output performance of the HAVG. Importantly, a self-powered aeolian vibration monitoring system is established and demonstrated for vibration-state sensing and abnormal vibration alarm. This work demonstrates a novel strategy for energy harvesting and state sensing of overhead transmission line aeolian vibration, which not only reveals TENG-EMG promising potential for energy harvesting for aeolian vibration, but also provides valuable guidance for the construction of a self-powered online-monitoring system for transmission lines.

Two-In-One: End-Emitting Blue LED and Self-Powered UV Photodetector based on Single Trapezoidal PIN GaN Microwire for Ambient Light UV Monitoring and Feedback.

With the continuous miniaturization and integration of the semiconductor industry, micro/nanoscale integrated photonics has received extensive attention as a key technology for optical communication, optical storage, and optical interconnection. Here, a two-in-one device is reported with both unidirectional blue light emission and UV photodetection functions based on single trapezoidal PIN GaN microwire. By constructing a Fabry-Perot resonator cavity structure, the end-emitting blue light-emitting diode with a low turn-on voltage (≈0.97V) and high color purity (full width at half maximum ≈22nm) is implemented. Furthermore, benefiting from the slow growth rate of the semipolar planes on both sides of the trapezoidal microwire and the high diffuse reflectivity of the patterned substrate, the trapezoidal microwire sides can be used as a high-performance UV photodetector. In self-driven mode, the device exhibits a large responsivity (0.218AW-1 ), high external quantum efficiency (83.31%) and fast response speed (rise/decay time of 0.48/0.98ms). Finally, the prepared two-in-one device is successfully integrated into ambient light UV monitoring and feedback system and tested. This work provides a novel strategy to combine luminescence with photodetection, demonstrating high potential for applications, such as on-chip photonic integration, energy-saving communication and ambient light monitoring and feedback system.

Meta-Model Assisted Continuous Vibration-Based Damage Identification of a Historical Rammed Earth Tower in the Alhambra Complex

ABSTRACT This work presents the development of a model-based online damage identification system for a 13th century rammed earth (RE) tower in the Alhambra, the Muhammad Tower. The system is fed with continuous data from an ambient vibration-based monitoring system and a meteorological station. Ambient vibrations are continuously processed through Operational Modal Analysis (OMA), and environmental effects are minimised via statistical pattern recognition. The normalized modal signatures are used to update the stiffness properties of certain parts of the tower through inverse model calibration. To do so, a high-fidelity three-dimensional finite element model (FEM) of the tower is developed. Since its computational burden precludes conducting online calibration, the FEM is bypassed by a light Kriging surrogate model (SM). In this light, the developed SM-assisted system identification constitutes a long-term Structural Health Monitoring (SHM) system outputting quasi-real-time series of modal properties and local stiffness parameters, so providing full damage assessment (detection, localization and quantification). The presented results refer to a time period of three months since January until March 2022. Numerical results and discussion are reported concerning the characterization and removal of environmental effects, and synthetic damage scenarios through non-linear simulations are used to validate the developed damage identification system.

Ambient Air Monitoring System With Adaptive Performance Stability

Ambient Air Monitoring System With Adaptive Performance Stability

Recent Progress in Cellulose-Based Flexible Sensors

Flexible sensors are attractive due to potential applications in body exercise and ambient gas monitoring systems. Cellulose and its derivatives have combined superiorities such as intrinsic and structural flexibility, ease of chemical functionalization, moisture sensitivity, and mechanical stability, enabling them to be promising candidates as flexible supporting substrates and flexible sensitive materials. Significant progress consequently has been achieved to improve mechanical, electrical, and chemical performance. The latest advance in materials synthesis, structure design, fabrication control, and working mechanism of novel cellulose-based flexible sensors are reviewed and discussed, including strain sensors, humidity sensors, and harmful gas sensors. Various strategies were summarized to enhance sensor performance by surface group modifications, inorganic and organic conducting fillers optimization, multilayer structure design. Newly emerged processing techniques of self-assembly, vacuum filtration, and 3D printing were introduced as well to construct multiscale microstructures. The integration of multiple sensors toward smart and healthy exercise monitoring system is briefly reviewed. The facing challenges and future opportunities of cellulose-based flexible sensors were discussed and proposed at the end. This review provides inspiration and guidelines on how to design and fabricate cellulose-based flexible sensors.

RaspMI: Raspberry Pi Assisted Embedded System for Monitoring and Recording of Seismic Ambient Noise

Recently, the passive seismic techniques based on the microtremor measurements have emerged as an alternative to conventional seismic and geotechnical methods used in engineering seismology and earthquake engineering, especially in the local site effect investigations. These methods are basically based on the recording of seismic ambient noise and analysis of its spectral features. Although these techniques are more practical than traditional seismic methods, the commercial instruments designed for recording the seismic ambient noise are quite expensive. Furthermore, most of these instruments require an external computer for recording and monitoring the data. In this sense, this article intends to present a low-cost and Raspberry Pi single-board microcomputer aided seismic ambient noise recording and monitoring system (RaspMI) as an alternative to the computer aided commercial seismic noise measurement systems. RaspMI is an open-source hardware and software system that is controlled by a graphical user interface developed by using the MonoDevelop cross-platform and C# programming language. This system has many features such as 72 dB dynamic range, 100 Hz sampling frequency, timer recording mode, text and SAC data file format, and latitude, longitude, date and time support with GPS module. RaspMI has subjected to the various tests in terms of the reliability and sensitivity. The obtained results have shown that RaspMI can be used as an alternative instrument for seismic ambient noise measurements.

Ambient understanding of stairway ascension and descension by the elderly using a handrail-based force sensor

For elderly persons, declining physical conditions (frailty) tend to lead directly to conditions requiring nursing care. As a result, it is necessary to detect the signs of such physical declines early and take appropriate supporting actions. However, since it is often difficult for elderly persons to notice these minor daily changes, the use of sensors is rapidly becoming essential. To that end, ambient sensors inserted into the homes of elderly persons offer one of the most promising ways of performing unobtrusive health monitoring. In the present study, as an ambient health monitoring system, the authors propose a handrail-based biaxial sensor device for stairways that can measure the biaxial force exerted on the handrail and thus facilitate understanding the ascension and descension characteristics of private home residents. The changes to these characteristics can then provide crucial information related to the residents’ physical conditions. Specifically, this paper describes a method for detecting signs of physical changes by measuring the speed and frequency of stairway usage. To verify the validity of the system, the authors installed the sensor system in the actual home of an elderly person and conducted 122 days of monitoring. This system, as well as the long-term monitoring results and system verification, are discussed below.

Examining spatiotemporal variability of urban particulate matter and application of high-time resolution data from a network of low-cost air pollution sensors

Traditional air monitoring approaches using regulatory monitors have historically been used to assess regional-scale trends in air pollutants across large geographical areas. Recent advances in air pollution sensor technologies could provide additional information about nearby sources, support the siting of regulatory monitoring stations, and improve our knowledge of finer-scale spatiotemporal variation of ambient air pollutants and their associated health effects. Sensors are now being developed that are much smaller and lower cost than traditional ambient air monitoring systems and are capable of being deployed as a network to provide greater coverage of a given area. The CitySpace project conducted by the US EPA and the Shelby County Health Department included the deployment of a network of 17 sensor pods using Alphasense OPC-N2 particulate matter (PM) sensors integrated with meteorological sensors in Memphis, TN for six months. Sensor pods were collocated with a federal equivalent method (FEM) tapered element oscillating microbalance (TEOM) monitor both before and after the primary study period. Six of the sensor pods were found to meet the data quality objective (DQO) of coefficient of determination (R2) greater than 0.5 when collocated with the TEOM. Seven pods were decommissioned before the end of the study due to mechanical failure. The six pods meeting the DQO were used to examine the spatiotemporal variability of fine PM (PM2.5) across the Memphis area. One site was found to have higher relative PM2.5 concentrations when compared to the other sites in the network. The 1-min data from this sensor pod were evaluated to quantify the regional urban background and local-scale contributions to PM2.5 at that monitoring location. This method found that approximately 20% of the PM2.5 was attributed to local sources at this location, compared to 9% at a local regulatory monitoring site. Additionally, the 1-min data were combined with 1-min wind speed and wind direction data to examine potential sources in the area using the nonparametric trajectory analysis (NTA) technique. This method geographically identified local source areas that contributed to the measured concentrations at the high reading sensor location throughout the course of the study.

Summertime Soil-Atmosphere Ammonia Exchange in the Colorado Rocky Mountain Front Range Pine Forest

Understanding the NH3 exchange between forest ecosystems and the atmosphere is important due to its role in the nitrogen cycle. However, NH3 exchange is dynamic and difficult to measure. The goal of this study was to characterize this exchange by measuring the atmosphere, soil, and vegetation. Compensation point modeling was used to evaluate the direction and magnitude of surface-atmosphere exchange. Measurements were performed at the Manitou Experimental Forest Observatory (MEFO) site in the Colorado Front Range by continuous online monitoring of gas and particle phase NH3-NH4+ with an ambient ion monitoring system coupled with ion chromatographs (AIM-IC), direct measurements of [NH4+] and pH in soil extracts to determine ground emission potential (Γg), and measurements of [NH4+]bulk in pine needles to derive leaf emission potential (Γst). Two different soil types were measured multiple times throughout the study, in which Γg ranged from 5 to 2122. Γst values ranged from 29 to 54. Inferred fluxes (Fg) from each soil type predicted intervals of emission and deposition. By accounting for the total [NH4+] pool in each compartment, the lifetime of NH3 with respect to the surface-atmosphere exchange in the soil is on the order of years compared to much faster naturally occurring processes, i.e., mineralization and nitrification.

Ambient loading and modal parameters for the Chulitna River Bridge

The Chulitna River Bridge is a 790-ft five girder, five-span steel bridge on the Parks Highway between Fairbanks and Anchorage, Alaska. This bridge was built in 1970 and widened in 1993. Under the no-live load condition, five support bearings are not in contact. Heavily loaded trucks often travel across this bridge to the oil fields in Prudhoe Bay, Alaska. A virtual finite element modeling, dynamic field testing of the “ambient vibrational response,” and structural health monitoring system are used to analyze, evaluate, and monitor the structural performance. As the first stage of the research, this article presents results from the dynamic testing and evaluation of the structural responses of the bridge. In the dynamic field testing, 15 portable accelerometers were placed on centerline along the bridge length to record the structural response, and an ambient free-decay response was used to evaluate the dynamic properties of the bridge structure. Natural frequencies and modal damping ratios were identified and characterized using Hilbert–Huang transform and fast Fourier transform methods. Compared with conventional approaches, this study demonstrates that (1) the Hilbert–Huang method was found to be effective and suitable for modal parameter identification of a long steel girder bridge using ambient truck loading; (2) the nonlinear damping was, for the first time, identified based on Hilbert–Huang transform’s amplitude–time slope; (3) modal frequencies are very sensitive to sensor location so their position should be optimized.

Technology and trust: older people's perspectives of a home monitoring system

ABSTRACTWith demographic changes and the growing numbers of older people living alone, concerns have been raised about the care of the ageing population. Increasingly, developments in technology are being seen as the solution to these concerns. For those who do not see themselves as old or frail enough to require personal care provision, and who prefer to maintain their identity as autonomous and independent individuals, the development of assistive technologies such as ambient home monitoring systems is one answer. However, this involves careful negotiations with older people's understandings of safety and privacy, and their experiences and relationships with technology, their carers and relevant service-providers. In two trials of a home monitoring system funded by the United Kingdom Technology Strategy Board, older people were interviewed pre-trial and post-trial about their perspectives on these issues. This paper presents a conceptual analysis of the qualitative data using a sociological framework of trust that considers habitual action, and relationships with kin and with wider institutions. The research found that older people's habits and norms do not need to be disrupted by the ambient system. What was of more importance was relationships between the older person and her or his ‘monitor’ based on trust, as well as institutional providers who need to instil or earn trust.

Optimized arrangement of constant ambient air monitoring stations in the Kanto region of Japan.

Continuous ambient air monitoring systems have been introduced worldwide. However, such monitoring forces autonomous communities to bear a significant financial burden. Thus, it is important to identify pollutant-monitoring stations that are less efficient, while minimizing loss of data quality and mitigating effects on the determination of spatiotemporal trends of pollutants. This study describes a procedure for optimizing a constant ambient air monitoring system in the Kanto region of Japan. Constant ambient air monitoring stations in the area were topologically classified into four groups by cluster analysis and principle component analysis. Then, air pollution characteristics in each area were reviewed using concentration contour maps and average pollution concentrations. We then introduced three simple criteria to reduce the number of monitoring stations: (1) retain the monitoring station if there were similarities between its data and average data of the group to which it belongs; (2) retain the station if its data showed higher concentrations; and (3) retain the station if the monitored concentration levels had an increasing trend. With this procedure, the total number of air monitoring stations in suburban and urban areas was reduced by 36.5%. The introduction of three new types of monitoring stations is proposed, namely, mobile, for local non-methane hydrocarbon pollution, and Ox-prioritized.

A High-Precision Marine Ambient Noise Sound Pressure Monitoring System

A high-precision marine ambient noise sound pressure monitoring system is developed based on the Michelson interference, a method of improving the measurement accuracy is presented by signal modulation and compensation. Experiments show that the monitoring system has a wide dynamic range and high accuracy especially in low-frequency.

Quantitative Evaluation of Surface Color of Tomato Fruits Cultivated in Remote Farm Using Digital Camera Images

To measure the quantitative surface color information of agricultural products with the ambient information during cultivation, a color calibration method for digital camera images and a remote monitoring system of color imaging using the Web were developed. Single-lens reflex and web digital cameras were used for the image acquisitions. The tomato images through the post-ripening process were taken by the digital camera in both the standard image acquisition system and in the field conditions from the morning to evening. Several kinds of images were acquired with the standard RGB color chart set up just behind the tomato fruit on a black matte, and a color calibration was carried out. The influence of the sunlight could be experimentally eliminated, and the calibrated color information consistently agreed with the standard ones acquired in the system through the post-ripening process. Furthermore, the surface color change of the tomato on the tree in a greenhouse was remotely monitored during maturation using the digital cameras equipped with the Field Server. The acquired digital color images were sent from the Farm Station to the BIFE Laboratory of Mie University via VPN. The time behavior of the tomato surface color change during the maturing process could be measured using the color parameter calculated based on the obtained and calibrated color images along with the ambient atmospheric record. This study is a very important step in developing the surface color analysis for both the simple and rapid evaluation of the crop vigor in the field and to construct an ambient and networked remote monitoring system for food security, precision agriculture, and agricultural research.

COMPARISON OF ENVIRONMENTAL RADIATION MONITORING PROGRAMS IN CHINA AND THE UNITED STATES

The monitoring of environmental radiation has been carried out across the United States by the U.S. Environmental Protection Agency's RadNet (formerly the Environmental Radiation Ambient Monitoring System, ERAMS) and the Global Network Program (GNP) of the Environmental Measurements Laboratory (EML), and in the People's Republic of China (PRC) by their National Radioactivity Contamination Monitoring System (NRCMS). It is expected that an awareness of the similarities and differences in the structure and operation of these programs will prove helpful to both countries and perhaps others as they continue to develop their monitoring capabilities.

The design and implementation of an agent-based framework for acceptable usage policy monitoring and enforcement

Reliance on the Internet in the workplace means that manually monitoring compliance with an Acceptable Usage Policy (AUP) is impractical given the volumes of data generated. Therefore, for such a system to function effectively, the processing of vast audit trails obtained must be processed by automated means. This paper introduces the incorporation of a novel user-monitoring framework into the domain of software agents for large-scale auditing of Internet use with possible extensions to general network use. It is intended that such an approach would replace current ad-hoc methods such as those based on perusing server logs with a more accurate representation of user activity. The system described herein is an experimental multi-agent one provisionally known as WebEngzilla, which actively monitors and reports on the Web browsing behaviour habits of network users unifying an ambient client monitoring system with a distributed data mining back end.

An ambient software monitoring system for unsupervised user modelling

This paper describes a means of unsupervised learning of recurring patterns in user activity through patterns in system level events generated by a graphical user interface. Earlier work has shown that using this distillation of the more complex behavioural interaction between the user and the application provides a symbolic representation of knowledge and goals that could be used to imply preference. Although prior research has explored the possibilities of removing this information acquisition bottleneck in such an expert system using ambient monitoring approaches, some have experienced difficulty in dealing with the varying length training sequences and segmentation of the continuous event stream. Unlike previous work the approach documented here handles interactions of varying sizes and is able to recall recurrent patterns in real time irrespective of the number of interactions learned. In addition to describing the proposed approach we also describe the shortcomings of various previously applied machine learning techniques on the same type of data. We also demonstrate a practical implementation of our approach applied to web browser usage.

PM2.5 particles and size-segregated ionic species measured during fall season in three urban sites in Korea

Abstract Twelve hours integrated fine particles (PM 2.5 ) and 24-h average size-segregated particles were collected to investigate the chemical characteristics and to determine the size distribution of ionic species during October–December 1999 in three cities of different urban scale; Chongju, Kwangju, and Seoul, Korea. Concentrations of 5-min PM 2.5 black carbon (BC) and hourly criteria air pollutants (PM 10 , CO, NO x , SO 2 , and O 3 ) were also measured using the Aethalometer and ambient air monitoring system, respectively. Highest PM 2.5 mass concentrations at Chongju, Kwangju, and Seoul sites were 63.0, 77.9, and 143.7 μg m −3 , respectively. For the time period when highest PM 2.5 mass occurred, BC level out of PM 2.5 chemical species was highest at both Chongju and Kwangju, and highest NO 3 − (23.6 μg m −3 ) followed by BC (23.1 μg m −3 ) were observed at Seoul site, indicating that highest PM 2.5 pollution is closely associated with the traffic emissions. Strong relationships of Fe with BC and Zn at both Kwangju and Seoul sites support that the Fe and Zn measured there are originated partly from same source as BC, i.e. diesel traffics. However, it is suggested that the Fe measured at Chongju is most likely derived from dispersion of soil dust. The size distributions of SO 4 2− , NO 3 − , and NH 4 + ionic species indicated similar unimodal distributions at all sampling sites. However, different unimodal patterns in the accumulation mode size range with a peak in the smaller size (0.28–0.53 μm, condensation mode) in both Kwangju and Seoul, and in the relatively larger size (0.53–1.0 μm, droplet mode) in Chongju, were found. The potassium ion under the study sites dominates in the fine mode, and its size distribution showed unimodal character with a maximum in the size range 0.56–1.0 μm.

Assessment of lead exposure and associated risk factors in urban children in Silesia, Poland

A program of childhood lead poisoning prevention was conducted in six cities of Silesia, the most industrialized region of Poland. We analyzed records of 11,877 children aged 24–84 months, tested between 1993 and 1998, to assess children's exposure to lead and associations of blood lead levels (BLL) with season of sampling, questionnaire data, and environmental levels of lead. Air lead concentrations and lead fallout, as measured in the ambient air monitoring system, were below current Polish air quality standards and gradually decreased. The geometric mean (GM) BLL was 6.3 μg/dL (range from 0.6 to 48 μg/dL), and >13% of children had BLL ⩾10 μg/dL. Mean BLL declined from 6.8 μg/dL in 1993–1994 to almost 5.5 μg/dL in 1998. GM BLL in spring and summer (‘nonheating’ season) months were 10% higher than BLL in children tested in fall and winter (‘heating’ season), although air lead concentrations were lower in nonheating and higher in the heating season. For both the heating and nonheating seasons, there was a significant increase in the mean BLL with increasing air lead concentrations. Poor housing (odds ratio (OR): 1.82; 95% CI: 1.4, 2.3), two or more siblings in the family (OR: 3.12; 95% CI: 2.6, 3.7), lack of recreational trips outside the region (OR: 1.66; 95% CI: 1.47, 1.89), and the time child spent outdoors were associated with elevated BLL. Variables found to affect BLL in the Silesian children should be used to propose criteria to improve identification of children at risk and to focus prevention activities more effectively.

PM 2.5 carbon measurements in two urban areas: Seoul and Kwangju, Korea

24-h PM 2.5 carbonaceous samples were collected between 27 November and 9 December 1999 in Seoul, and between 7 and 20 June 2000 in Kwangju to investigate characteristics of carbonaceous species, and the relationship between elemental carbon (EC) and Aethalometer-based black carbon (BC) measurements. 5-min PM 2.5 BC and criteria air pollutant data were also measured using the Aethalometer and ambient air monitoring system. The PM 2.5 samples were analyzed for EC and OC using a selective thermal manganese dioxide oxidation (TMO) method. The daily average EC and OC concentrations in Seoul were higher in the winter than in the summer (Atmos. Environ. 35 (2001a) 657). It was found that difference between ambient BC levels in the two cities was not directly proportional to the population ratio (∼8) or diesel traffic ratio (∼5.9) since particulate matter or BC concentration is strongly influenced by a result of varying traffic and meteorological conditions at the site. Using the primary OC/EC ratio approach, the results suggest that most of the measured OC in Kwangju is of primary origin during the summer. In Seoul, the observed OC includes additional secondary organic aerosol during the wintertime conditions. The relationship between the 24-h TMO-EC and Aethalometer BC measurements in PM 2.5 reflected very good agreement for the two urban sites, with correlation coefficients of R 2=0.99 and 0.92, and BC/EC slopes of 0.93 and 1.07, respectively. It was found that comparing TMO-EC to BC at a different location in Korea, a different scaling factor was needed.