A review of previous studies on the applications of fiber optic sensing technologies in geotechnical monitoring

Geotechnical engineering is characterized by many uncertainties,including soil material properties,environmental effects,and engineering design and construction,which bring a significant challenge to geotechnical monitoring.However,conventional sensors with several inherent limitations,such as electromagnetic interference,signal loss in long-distance transmission,and low durability in harsh environments cannot fully meet current monitoring needs.Recently,fiber optic sensing technologies have been successfully applied in geotechnical monitoring due to the significant advantages of anti-electromagnetic interference,stable signal long-distance transmission,high durability,high sensitivity,and lightweight,which can be considered an ideal replacement for conventional sensors.In this paper,the working principle of different fiber optic sensing technologies,the development of fiber optic-based sensors,and the recent application status of these sensing technologies for geotechnical monitoring were comprehensively reviewed and discussed in detail.Finally,the challenges and countermeasures of the sensing technologies in geotechnical monitoring were also presented and discussed.

Structural Deformation Monitoring of Flight Vehicles Based on Optical Fiber Sensing Technology:A Review and Future Perspectives

Structural deformation monitoring of flight vehicles based on optical fiber sensing(OFS)technology has been a focus of research in the field of aerospace.After nearly 30 years of research and development,Chinese and international researchers have made significant advances in the areas of theory and methods,technology and systems,and ground experiments and flight tests.These advances have led to the development of OFS technology from the laboratory research stage to the engineering application stage.However,a few problems encountered in practical applications limit the wider application and further development of this technology,and thus urgently require solutions.This paper reviews the history of research on the deformation monitoring of flight vehicles.It examines various aspects of OFS-based deformation monitoring including the main varieties of OFS technology,technical advantages and disadvantages,suitability in aerospace applications,deformation reconstruction algorithms,and typical applications.This paper points out the key unresolved problems and the main evolution paradigms of engineering applications.It further discusses future development directions from the perspectives of an evolution paradigm,standardization,new materials,intelligentization,and collaboration.

A new algorithm of retrieving a petroleum substances absorption coefficient in sea water based on a remote sensing image

Establishing the remote sensing algorithm of retrieving the absorption coefficient of seawater petroleum substances is an efficient way to improve the accuracy of retrieving a seawater petroleum concentration using a remote sensing technology. A remote sensing reflectance is a basic physical parameter in water color remote sensing. Apply it to directly retrieve the absorption coefficient of seawater petroleum substances is of potential advantage. The absorption coefficient of waters containing petroleum [ACWCP, a_o（λ）], consists of the absorption coefficient of pure water [ACPW, a_w（λ）], plankton [ACP, a_（ph）（λ）], colored scraps [ACCS, a_（d,g）（λ）], and petroleum substance [ACPS, a_（oil）（λ）]. Among those, ACCS consists of the absorption coefficient of nonalgal particle [ACNP, a_d（λ）] and colored dissolved organic matter [ACCDOM, a_g（λ）]. For waters containing petroleum, the retrieved ACCS using the existing method is a combination absorption coefficient of ACNP,ACCDOM and ACPA [CAC, a_（d,g,oil）（λ）]. Therefore, the principle question is how to extract ACPS from CAC.Through the analysis of the three proportion tests conducted between the year of 2013 and 2015 and the corresponding remote sensing data, an algorithm of retrieving the absorption coefficient of petroleum substances is proposed based on remote sensing reflectance. First of all, ACPS and CAC are retrieved from the reflectance using the quasi-analytical algorithm（QAA）, with some parameter modified. Secondly, given the fact that the backscatter coefficient [BC, b_（bp）（555）] of total particles at 555 nm can be obtained completely from the reflectance, the relation between BC and ACNP in petroleum contaminated water can be established. As a result, ACNP can be calculated. Then, combining the remote sensing retrieving algorithm of a_g（440）, the method of achieving the spectral slope of the absorption coefficient can be established, from which ACCDOM,can be calculated. Finally, ACPS can be computed as the residual. The accuracy of ACPS based on this algorithm is 86% compared with the in situ measurements.

APPLICATION OF REMOTE SENSING TECHNOLOGY TO POPULATION ESTIMATION

This paper attempts to explore a new avenue of urban small-regional population estimation by remote sensing technology, creatively and comprehensively for the first time using a residence count method, area (density) method and model method, incorporating the application experience of American scholars in the light of the state of our country. Firstly, the author proposes theoretical basis for population estimation by remote sensing, on the basis of analysing and evaluating the history and state quo of application of methods of population estimation by remote sensing. Secondly, two original types of mathematical models of population estimation are developed on the basis of remote sensing data, taking Tianjin City as an example. By both of the mathematical models the regional population may be estimated from remote sensing variable values with high accuracy. The number of the independent variables in the latter model is somewhat smaller and the collection of remote sensing data is somewhat easier, but the deviation is a little larger. Finally, some viewpoints on the principled problems about the practical application of remote sensing to population estimation are put forward.

The Sensing Principle of FBG and Its Experimental Application in Structure Strengthening Detection

Based on the basic theory of the fiber Bragg grating sensor,a kind of stickup FBG sensor is developed,which is applied in the structure strengthening.With the experiment of the FBG senor and the common electricity sensor stuck on the reinforced structure,the result shows that the FBG sensor not only has a high performance,but also can realize the control on the spot and on the line.

Research on the evolution law of permafrost under the influence of urbanization based on remote sensing technology

The permafrost of Mohe County and its suburbs in the Daxing′an Mountains has been influenced by the urbanization.Remote sensing,GIS technology and numerical simulation was used to study the temperature variations of permafrost with the changes in surface vegetation that cover Mohe County and suburban areas,and the law of permafrost degradation on the study area was analyzed.The research results show that the urban area of the study area increased 114.42%from 2000 to 2016,and the urbanization process is continuing to accelerate.The Normalized Difference Vegetation Index map of 2017 in Mohe County and its suburbs was studied and the maximum proportion of vegetation coverage was different in the four seasons.The numerical calculation model results show that the permafrost temperature change in the study area cyclically fluctuates in a cosine form.The annual variation curve of permafrost temperature gradually decreased and its accompanying phase lag increased with depth.The annual temperature change value with the different depths of the town was greater than the natural ground.The maximum permafrost thawing depths of the town and natural ground were 4.2 m and 2.82 m in 50 a,and the degradation rates of the two permafrost are,respectively,0.88 cm/a and 0.46 cm/a.These results show that urbanization has accelerated the degradation of permafrost.

Application of High-Resolution Remote Sensing Technology in Quantitative Study on Coseismic Surface Rupture Zones: An Example of the 2008 M_w7.2 Yutian Earthquake

Objective Nowadays, high-resolution remote sensing technology has brought new changes to surveys of earthquakes, and the quantitative study of seismic faults based on this technology has become a trend in the world(Barzegari et al., 2017). An Mw 7.2 earthquake occurred in Yutian of Xinjiang on the western end of the Altyn Tagh fault on March 21 st, 2008. It is difficult to access this depopulated zone because of the high altitude and only 1–2 months of snowmelt. This study utilized high-resolution

Force Sensing Resistor and Its Applicationto Robotic Control

Abstract: The force sensing resistor (FSR) and its con’struction and characteristic are described. By using the optimal electronic interface, the end result which is a direct proportionality between force and voltage is obtained. The circuits of application for force and position measurements in the robotic control are given. The experiment that FSRs are placed on the fingers of BH - 1 dexterous hand as tactile sensors to measure the contacting forces shows FSR’s force sensitivity is optimized for use in the control of robot contacting with environment.

THE LAND USE INVESTIGATION IN TIBET PLATEAU USING REMOTE SENSING TECHNOLOGY

Tibet Plateau is Known as "the Roof of the World" with the area of 1,220,000km^2, which is about 1/8 land area of China. Because of the high elevation, cold climate and it caused difficulties in regional economic planning and land resources management. Since 1985, the land use investigation in Tibet has been carried out, in which the basic data and thematic maps must be obtained and completed at county and township levels, in order to meet the needs of local administrations. In the investigation, remote sensing technology was comprehensively adopted. At present, the investigation in county level had been completed and the compilation is going to be carried out. Due to paying a great attention to studying on a series of key technical problems, the systematic methods of using remote sensing technology in the plateau land use investigation were formed and successfully put into application.

Remote Sensing Technology and Applications for Earthquake Disasters

Disaster warning,disaster estimation and relief depend more and more on the application of space remote sensing technologies,such as those used for optic-camera,hyperspectrum,infrared,SAR,seismo-electromagnet and gravitation measurement.On May 12,2008,a magnitude of 8.

Applications of Satellite Remote Sensing Technology in China's Environmental Monitoring

The environmental conditions in China are still very serious. In the years to come, the mission for environmental treatment and protection, supervision,

Human Respiration Rate Estimation Using Ultra-wideband Distributed Cognitive Radar System

It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture.

Effectiveness of Fiber Bragg Grating monitoring in the centrifugal model test of soil slope under rainfall conditions

Centrifugal model testsare playing an increasingly importantrolein investigating slope characteristics under rainfall conditions. However, conventional electronic transducers usually fail during centrifugal model tests because of the impacts of limitedtest space, high centrifugal force, and presence of water, with the result that limited valid data is obtained. In this study, Fiber Bragg Grating(FBG) sensing technology is employed in the design and development of displacement gauge, an anchor force gauge and an anti-slide pile moment gauge for use on centrifugal model slopes with and without a retaining structure. The two model slopes were installed and monitored at a centrifugal acceleration of 100 g. The test results show that the sensors developed succeed in capturing the deformation and retaining structure mechanical response of the model slopes during and after rainfall. The deformation curvefor the slope without retaining structure shows a steepresponse that turns gradualfor the slope with retaining structure. Importantly, for the slope with the retaining structure, results suggest that more attention be paid to increase of anchor force and antislide pile moment during rainfall. This study verifies the effectiveness of FBG sensing technology in centrifuge research and presents a new and innovative method for slope model testing under rainfall conditions.

Terahertz polarization sensing,chirality enhancement,and specific binding based on metasurface sensors for biochemical detection:a review[Invited]

Specific and highly-sensitive biochemical detection technology is particularly important in global epidemics and has critical applications in life science,medical diagnosis,and pharmaceutics.As a newly developed technology,the THz metamaterialbased sensing method is a promising technique for extremely sensitive biomolecular detection.However,due to the significant resonant peaks generated by THz metamaterials,the characteristic absorption peaks of the analyte are usually masked,making it difficult to distinguish enantiomers and specifically identify target biomolecules.Recently,new ways to overcome this limitation have become possible thanks to the emergence of chiral metasurfaces and the polarization sensing method.Additionally,functionalized metasurfaces modified by antibodies or other nanomaterials are also expected to achieve specific sensing with high sensitivity.In this review,we summarize the main advances in THz metamaterials-based sensing from a historical perspective as well as application in chiral recognition and specific detection.Specifically,we introduce the basic theory and key technology of THz polarization spectrum and chiral sensing for biochemical detection,and immune sensing based on biomolecular interaction is also discussed.We mainly focus on chiral recognition and specific sensing using THz metasurface sensors to cover the most recent advances in the topic,which is expected to break through the limitations of traditional THz absorption spectroscopy and chiral spectroscopy in the visible-infrared band and develop into an irreplaceable method for the characterization of biochemical substances.

Dynamics Analysis of Surface Temperature and Vegetation Index in Settlement Area around the Lokon Volcano, Tomohon, North Sulawesi

Mount Lokon is an active mountain near residential areas such as cities Tomohon, Tondano, and Manado. Along with the increasing population and population development around Mount Lokon, vegetation is decreasing due to converting land from grassland to land use for human activities. Using Landsat 8 OLI/TIRS images, this study was conducted to analyze the surface temperature and vegetation index dynamics around Mount Lokon, including the residential areas. Found that an increase in mean temperature occurred, and the peak increased dramatically in 2018 with temperatures > 26˚C. This result, of course, correlates with the decreasing vegetation area. However, the decline occurred in 2020 due to decreased human activities and land clearing for new settlements caused by activity restrictions which were the effects of the COVID-19 pandemic. Reforestation efforts must be made to increase the vegetation around Mount Lokon, including residential areas. The average surface temperature can be controlled, and living creatures can be given comfort to living things around them even after the pandemic and human activities return to normal.

Sense of Science and Technology in Product Design

Sense of science and technology has become the trend of modem design, but the commonly acknowledged sense of science and technology is different from science and technology itself. Starting from machine aesthetics and high-tech style, combined with the changing process of the sense of science and technology, it analyzes the causes and related social factors, style characteristics and manifestations of the sense of science and technology, as well as the inherent relationship of multi-angle analysis technology and the sense of science and technology. It illustrates the social value and defects of artistic expression of the sense of science and technology and reflects on the connection and difference between science and technology on the one hand and the sense of science and technology on the other hand.

A method of monitoring and locating eggs laid by breeding geese based on photoelectric sensing technology

On the current breeding goose farm,the detection of individual egg laying mainly depends on some judgement experiences of farm workers.At present,there have been some egg laying detection systems developed with images and weighing sensors,which only signal the eggs being laid,but no egg position being achieved.Meanwhile,the detection rate of the system is not high due to environment limitations like dim light of the goose barn.Therefore,to solve these problems mentioned above,an intelligent detection and positioning system is pro-posed by integrating technologies of the Radio Frequency(RF)and photoelectric sensors,together with the geometric calculation principle.In this research,individual egg laying information of breeding geese in a non-cage state was examined to improve the level of auto-matic detection and positioning in the field of breeder egg production.The results showed that an accurate detection and positioning of an egg in a nest filled with the artificial turf could be achieved under some conditions:the height of sensor is 3.5 cm from the bottom plate of the egg laying nest,the spacing of the photoresistor module is 5 cm,and the external light intensity is less than 110 LUX.It also shown that the error of the goose egg position recognition is 0.443 cm with a suitable level of straw in the nest.Therefore,the monitoring system and positioningmethod that was developed in this research could provide a reference for the analysis of individual egg laying behavior,and could result in an improvement in the automatic egg collection for the breeding geese production.

Crop classification based on the spectrotemporal signature derived from vegetation indices and accumulated temperature

Due to differences in environmental factors,the phenology of the same crop is different every year,causing divergent performances of the classifier built by spectral or time-series features Here,we proposed a random forest classifier(RFC)based on an asymmetric double S curve model fitted by accumulated temperature(AT)and Vegetation Index(VI),which can be applied in different years without ground samples.We built AT and VI time series from Moderate Resolution Imaging Spectroradiometer 8-day composites of land surface temperatures and Sentinel-2 and Landsat-8,respectively.The RFC was trained by characteristics from the asymmetric double S curve.We prepared RFC by ground samples of 2018 and 2019 and then mapped crops of the same region in 2017.Results indicated that,compared with diverse VI-AT series,the overall accuracy based on universal normalized vegetation index(UNVI)was the best of all(2017:F1=0.91,2018:F1=0.92,2019:F1=0.91)and better than that based on the UNVI-TIME series(2017:F1=0.84,2018:F1=0.81,2019:F1=0.88).It proved that the classification features from the VI-AT series have smaller intra-class differences in 2017,2018,and 2019.

Geoinformatics education in China

The paper gives an overview of the current status of education in geoinformatics in China.First,the paper provides a brief introduction to the history of geoinformatics education in China and a general review of the scientific and technological development.It then presents how the development affects the education and training in China.In the paper,universities and institutes in China that can award academic degrees related to geoinformatics are summarized,and undergraduate majors are briefly introduced.Next,the paper reports the work having been done by the national expert group on Surveying and Mapping,including the revision of discipline catalog and guide for graduate education and requirements.A list of typical curricula in geoinformatics education is suggested.Activities on promoting the graduate student exchange platform are presented.Finally,a case study of geoinformatics education in Wuhan University is discussed.