WO2021240338A1 - Avalanche and landslides prevention monitoring system with fbg sensors - Google Patents
Avalanche and landslides prevention monitoring system with fbg sensors Download PDFInfo
- Publication number
- WO2021240338A1 WO2021240338A1 PCT/IB2021/054482 IB2021054482W WO2021240338A1 WO 2021240338 A1 WO2021240338 A1 WO 2021240338A1 IB 2021054482 W IB2021054482 W IB 2021054482W WO 2021240338 A1 WO2021240338 A1 WO 2021240338A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fiber optic
- optic conductor
- fbg sensors
- declivity
- slope
- Prior art date
Links
- 238000012544 monitoring process Methods 0.000 title claims abstract description 42
- 230000002265 prevention Effects 0.000 title claims abstract description 41
- 239000004020 conductor Substances 0.000 claims abstract description 74
- 239000000835 fiber Substances 0.000 claims abstract description 72
- 238000000034 method Methods 0.000 claims abstract description 34
- 238000012545 processing Methods 0.000 claims abstract description 15
- 230000004044 response Effects 0.000 claims abstract description 7
- 230000003287 optical effect Effects 0.000 claims description 19
- 230000006870 function Effects 0.000 claims description 15
- 230000001133 acceleration Effects 0.000 claims description 13
- 238000004873 anchoring Methods 0.000 claims description 12
- 239000011159 matrix material Substances 0.000 claims description 6
- 238000010801 machine learning Methods 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 4
- 238000007619 statistical method Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 2
- 230000001537 neural effect Effects 0.000 claims description 2
- 238000000605 extraction Methods 0.000 claims 1
- 239000002689 soil Substances 0.000 abstract description 2
- 239000010410 layer Substances 0.000 description 11
- 239000013307 optical fiber Substances 0.000 description 9
- 238000001514 detection method Methods 0.000 description 8
- 230000008901 benefit Effects 0.000 description 6
- 238000013507 mapping Methods 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000006073 displacement reaction Methods 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 238000004026 adhesive bonding Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000295 complement effect Effects 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000036961 partial effect Effects 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 230000036962 time dependent Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 241001465754 Metazoa Species 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 230000011664 signaling Effects 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35306—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement
- G01D5/35309—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer
- G01D5/35316—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer using a Bragg gratings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/3537—Optical fibre sensor using a particular arrangement of the optical fibre itself
- G01D5/35374—Particular layout of the fiber
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/01—Measuring or predicting earthquakes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/22—Transmitting seismic signals to recording or processing apparatus
- G01V1/226—Optoseismic systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/28—Processing seismic data, e.g. for interpretation or for event detection
- G01V1/288—Event detection in seismic signals, e.g. microseismics
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V8/00—Prospecting or detecting by optical means
- G01V8/02—Prospecting
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/02—Alarms for ensuring the safety of persons
- G08B21/10—Alarms for ensuring the safety of persons responsive to calamitous events, e.g. tornados or earthquakes
Definitions
- the present invention refers to an avalanche and landslide prevention monitoring system with FBG sensors.
- the present invention refers to an avalanche and landslide safety prevention system defined by a monitoring method for detecting and analyzing movements and an apparatus for implementing the same method using FBG optical fiber sensors.
- a further operational limitation is due to the fact that normal electronic detection devices are sensitive to radio and electromagnetic noise and disturbances.
- Last but not least limit of these known systems is due to the fact that they are particularly expensive, especially if deployed over long distances.
- a further limitation of these traditional detection systems is that they depend on a closed electrical circuit, where the interruption of any part of causes the detection system to fail. Yet a further limitation of these traditional detection systems is that they are poorly resistant to humidity and corrosion caused by weathering.
- the object of the present invention is to overcome and obviate, at least in part, the above- mentioned drawbacks and operating limits.
- the object of the present invention is to provide an avalanche and landslide prevention monitoring system with FBG sensors, capable of a constant monitoring, in real time and in remote, of the physical conditions of the snowpack or of the terrain of a slope or declivity.
- a further object of the present invention is to provide to the user an avalanche and landslide prevention monitoring system with FBG sensors, capable of detecting in real time any changes in position and temperature of the snowpack or terrain of a slope or declivity, generating an alarm by means of signaling systems.
- Still another object of the present invention is to provide an avalanche and landslide prevention monitoring system with FBG sensors, capable of guaranteeing a high level of resistance and reliability over time and such as to be easily and economically implemented and maintainable.
- optical fiber sensors FBG Fiber Bragg Grating
- FBGs type optical fiber sensors
- Each single FBG sensor is formed by directly etching a periodic diffractive grating, or Bragg grating, into the optical conductive medium (core), which is defined by a series of micro-incisions in the optical fiber configured to function as optical filters of the light signal that reflect or let pass certain wavelengths or colors of the optical spectrum emitted by a light source (LED).
- LED light source
- the detection portion of a fiber optic sensor chain is given by FBG segments, typically between 10 and 20 millimeters in length, that can be connected along the fiber optic conductor, exactly in the points where sampling is required.
- a single fiber optic conductor can carry a multiplicity of FBG sensors connected in series, significantly reducing weight and space compared to similar sensors based on electrical and electronic technologies, each of which requires dedicated wiring. This feature allows to provide measurement chains with lengths ranging from a few tens of meters to several kilometers and such that they can be easily structured, with an elementary wiring and simple control hardware.
- the continuous light signal emitted by a light source is reflected on predefined wavelengths by the FBG sensor network and detected in return by a spectrometer.
- a light source typically a super-luminescent or SLED type
- Both hardware components are extremely small in size and weight and have low power consumption.
- the hardware incorporated with the FBG network is also extremely small in size and generally includes a SLED unit, the spectrometer and a control computer CPU and various interfaces for connecting to recording storage or data transmission units on site or remotely.
- External mechanical and physical factors such as mechanical elongation induced on the fiber optic cable, vibrations, thermodynamic temperature etc. lead to a deformation of the Bragg grating, such as to alter the distance between the micro incisions on the optical fiber and cause a wavelength shift of the reflected light signal. This shift in the wavelength of the reflected light, appropriately calibrated, provides a dynamic measure of the elongation undergone by the fiber optic cable.
- the arrangement of a plurality of FBG sensors configured in series along the fiber optic conductor advantageously allows further physical parameters in real time, such as for example temperature, pressure, acceleration. It is therefore evident how a single fiber optic cable can have the functionality of several measuring sensors.
- the object of the present invention is that of an optical system that integrates in an innovative way the FBG sensors in an avalanche and landslide prevention monitoring system, in such a way as to advantageously determine the state parameters or the chemical-physical conditions of the snowpack. or of the terrain, which precede these phenomena, in such a way as to prevent their disastrous effect on people or things.
- Figure 1 is a schematic representation of a perspective view of the apparatus for implementing the avalanche and landslide preventing monitoring method with FBG sensors object of the present invention arranged on mountain slopes or declivity;
- Figure 2a is a schematic representation of a partial view of the optical fiber cable provided with a plurality of FBG sensors of the implementation apparatus of the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention
- Figure 2b is a schematic representation in transparency of a detail view of a single FBG sensor of the optical fiber cable of the apparatus for implementing the avalanche and landslide prevention monitoring method object of the present invention
- Figure 3 is a schematic representation of a partially sectioned side view of an embodiment of the apparatus for implementing the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention, with sections of cable and FBG sensors arranged alternately along the direction of the slope or declivity and perpendicular thereto;
- Figure 4 is a schematic representation of a partially sectioned side view of a further embodiment of the apparatus for implementing the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention, with the cable and the FBG sensors arranged at the below the surface of the slope or declivity;
- Figures 5a and 5b are partial schematic representations of detailed views of the fiber optic conductor of the apparatus for implementing the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention, provided with means for anchoring to the snowpack and to the terrain;
- Figures 6a and 6b are a schematic representation in perspective view of some examples of geographical arrangement on mountain slopes or declivity of the apparatus for implementing the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention
- Figure 7 is a schematic representation of the operation of a traditional optical detection or sensing system with the FBG type sensors
- Figure 8 is a schematic representation of a flowchart of the avalanche and landslides prevention monitoring method object of the present invention.
- an avalanche and landslide prevention monitoring system with FBG sensors comprising a method 100 and an apparatus 10 which implements the method 100.
- the method 100 for avalanche and landslide prevention monitoring comprising the steps of: 102 providing at least one fiber optic conductor 12 comprising a plurality or array of differently spaced FBG sensors 14 along a snow-covered o landslide-prone slope or declivity 90;
- control unit 20 106 acquiring as input and in real time at least one light signal reflected by one or more FBG sensors 14 by means of an optical detector (not shown) typically arranged within said control unit 20;
- step 110 obtaining at the output a three-dimensional map of the temperatures and 110' obtaining at the output a map of the micro-movements, vibrations or accelerations of the snowpack or of the terrain as a result of said step 108 of processing the signal of the wavelength changing of said at least a reflected light signal;
- the method 100 can comprise in succession to step 102 the further step of: providing a plurality of fiber optic conductors 12 comprising a plurality of FBG sensors 14 arranged to define a grid or a matrix 13 arranged on a surface or area of a slope or declivity 90.
- the avalanche and landslide prevention monitoring method 100 may also comprise, before step 122 comparing the values of said three-dimensional map of temperatures, micro-movements, vibrations and accelerations with threshold values of reference parameters or supplementary data, the acquisition of additional supplementary and complementary data from different sources with further steps of:
- 118 generate a three-dimensional map of the FBG sensors 14 distinguishing between their type and functionality on the three-dimensional terrain map and; 118' generate a three-dimensional map of the snowpack pressures on said slope or declivity 90 per centimeter [cm] of snow, 3D model of gravitational forces as a function of snowfall and any other parameters such as percentage humidity, accelerations etc. of snowpack or terrain; - 118" generate a map of the distribution of vegetation and additional complementary characteristics such as friction, thermal conductivity and composition of the materials constituting the terrain or present on the ground of the slope and declivity 90.
- the step 108 of processing the wavelength changing signal as a function of time of said at least one reflected light signal can be preceded by a step of: - 120 filtering of the acquired data with known sampling algorithms and extracting of significant events, such as moving averages etc., of data on localized and non- localized vibrations, terrain movements, percentage humidity changes etc., so as to reduces the amount of data, handling and speeding up the processing of the control unit 20 while maintaining an acceptable data approximation.
- the step 108 of processing the wavelength changing signal as a function of time of said at least one reflected light signal may comprise a step of:
- Step 122 of comparing the values of said three-dimensional map of temperatures and of said map of micro-movements, vibrations or accelerations of the snowpack or of the terrain with threshold values of benchmarks parameters or integrative data may comprise an operation of; generating one or more event predictive algorithms by means of known machine learning techniques, statistical analysis and neuronal networks.
- Said step 122 of comparing the values of said three-dimensional map of temperatures and of said map of micro-movements, vibrations or accelerations of the snowpack or of the terrain may also be preceded by further data integration steps:
- 132 integrating a surface temperatures map with data detected by means of one or more infrared IR cameras arranged in a position facing the surface of the snowpack of the slope or declivity 90, said IR cameras being advantageously arranged on an opposite slope or on poles 18.
- Said phase 122 of comparing the values of said three-dimensional temperatures map and of said map of micro-movements, vibrations or accelerations of the snowpack or of the terrain can also be preceded and followed by a step of:
- the arrangement of multiplicity of fiber optic conductors 12 comprising FBG sensors 14 and arranged in such a way as to form a grid or a matrix 13, has the important and innovative advantage of being able to cover an area or surface of the slope or declivity 90 and to monitor or punctually mapping the physical conditions of the snowpack or terrain at each point of the grid or matrix 13.
- the step 110 obtaining at the output a three-dimensional map of the temperatures and 110' obtaining at the output a map of the micro-movements, vibrations or accelerations of the snowpack or of the terrain as a function of the comparison with threshold values of reference parameters can comprise the determination of a relative length to the elongation or deformation of the fiber optic conductor 14, so as to function as a strain sensor.
- the step 110 of obtaining at the output a three-dimensional map of the temperatures and 110' obtaining at the output a map of the micro-movements, vibrations or accelerations of the snowpack or of the terrain as a function of the comparison with threshold values of reference parameters can also comprise, for certain FBG sensors 14, determining other further physical parameters of the snowpack or of the terrain such as thermodynamic temperature, pressure, acceleration, vibrations applied to the fiber optic conductor 12.
- the step 102 of providing at least one fiber optic conductor 12 comprising a plurality of FBG sensors 14, arranged along a slope or declivity 90 can comprise further steps of:
- fiber optic conductor 12 comprising a plurality of FBG sensors 14 arranged along the direction of the slope or declivity 90 or of descent of the avalanche or landslide and
- fiber optic conductor 12 comprising a plurality of FBG sensors 14 arranged in a substantially perpendicular direction, along the direction of the force of gravity or in any case not along the direction of the slope or declivity 90 by means of poles 18.
- the arrangement of a portion of fiber optic conductor 12 with FBG sensors 14 in a substantially perpendicular direction or along the direction of the force of gravity or in any case not along the direction of the slope or declivity 90 or of natural descent of the avalanche or landslide has the important advantage of being able to have FBG sensors 14 in each single overlapping layer of snow at different densities, accumulated on said slope or declivity 90, thus allowing a detection of the parameters relating to each single layer of snow as well as to determination itself of the number of layers subsequently overlapped.
- the step 102 of providing at least one fiber optic conductor 12 comprising a plurality of FBG sensors 14 arranged along a slope or declivity 90 can further comprise a step of:
- the fiber optic conductor 12 is a circular section cable, generally smooth on the surface and without any roughness, in order to better detect the movements of the snowpack or of the terrain it can advantageously be provided with means for anchoring the outer surface with the snow or on the terrain or soil or rock, such as for example projections or protrusions 80, corrugations 81, disks 82, as shown as example in Figure 5a.
- Said anchoring means are suitable for making the fiber optic conductor 12 integral with the snowpack or can be pegs 84, staples or other known types of gluing, suitable for stabilizing the fiber optic conductor 12 to the terrain so as to make it integral with the same in the movements, as shown as example in figure 5b.
- an avalanches and landslides prevention monitoring apparatus 10 comprising: at least one fiber optic conductor 12, generally a traditional circular cross-sectional cable having a transmitting optical core 15 and a protective coating 16, comprising a plurality of FBG sensors 14 formed in said core 14 by means of incisions 14 1 defining a Bragg grating, said conductor 12 being suitable to be arranged along the snow-covered surface or landslide- prone slope or declivity 90 and connected at one end thereof; a control unit 20 comprising an optical illuminator (not shown) configured to sending an optical signal through said fiber optic conductor 12, and comprising an optical receiver (not shown) configured to receiving a return light signal from said fiber optic conductor, said control unit 20 comprising a computer or CPU being configured to:
- Said fiber optic conductor 12 is generally arranged, in a simple embodiment, along the shortest linear descent direction of the slope or declivity 90, but it can also be arranged according to other directions, to also form complex curvilinear or mixed-linear sections, such as for example a wavy line, in order to arrange a greater number of FBG sensors 14 on the surface of said slope or declivity 90.
- said fiber optic conductor 12 can also be arranged under the terrain surface of said slope or declivity 90.
- the apparatus can also advantageously comprise a plurality of fiber optic conductors 12 provided with FBG 14 sensors, arranged to define a grid or array 13 of FBG sensors 14arranged to cover a surface or area (or a portion thereof), of a slope or declivity 90.
- Said FBG sensors 14 are arranged in series along the same fiber optic conductor 12 and can be uniformly or differently spaced from each other in such a way as to define portions or portions of the fiber optic conductor 12 more or less dense than FBG sensors 14.
- a plurality of optical fiber sensors 12 can also advantageously be collected in a bundle or cable of independently illuminated conductors and able to branch and separate along their development in such a way as to be able to selectively arrange themselves in the different zones or areas where the presence of sensors FBG 14 where sampling is needed.
- Said FBG sensors 14 can also be differently configured, independently of one another, in such a way that each can function as:
- a strain sensor configured to sensing or detecting (measuring) a length displacement
- a temperature sensor configured to detect a temperature
- a pressure sensor configured to determine a pressure acting on the external surface of the sensor FBG
- an accelerometer or seismograph configured to detecting a change in the speed of movement of the fiber optic conductor 12.
- the apparatus 10 can advantageously comprise at least a or a parallel section 12', of said fiber optic conductor 12 comprising a multiplicity of sensors FBG 14, arranged along the direction of the slope or declivity 90 and comprising at least a portion or emerging section 12" of fiber optic conductor 12 comprising a plurality of sensors FBG 14, said portion or emerging section being preferably arranged in a substantially perpendicular direction , or in any case not parallel to the direction of the slope, by means of poles 18 fixed in the terrain of the slope or declivity 90 in a substantially perpendicular way, as in the example of figure 3, or along the vertical line of direction of gravity .
- Said poles 18 can be made of any suitable structural material such as for example metal, wood, polymeric materials, concrete or equivalent. Said poles 18 can also be advantageously provided with fixing and supporting means (not shown) of the fiber optic conductor 12 such as for example eyelets, openings or support brackets suitable for allowing the support and movement of said fiber optic conductor 12 avoiding its damage.
- Said poles 18 can also be advantageously provided with visual means, for example can be colored, in order to be easily identifiable on the surface of the snow.
- This solution allows the emerging sections 12" of said fiber optic conductor 12 to cross with the relative FBG sensors 14 a plurality of possible layers 30, 30', 30" of the snowpack, having different chemical-physical characteristics, which can settle on the slope or declivity 90, in such a way as to arrange at least one FBG sensor 14 inside each layer 30, 30', 30" and, possibly, also at least one FBG 14 sensor in contact with the atmosphere environment.
- Said parallel section 12' and said emerging section 12" of the fiber optic conductor 12 can also be advantageously configured in such a way as to arrange a different number of FBG sensors 14 on each portion, with different distance between them and configured in such a way to reveal or measure different quantities or physical parameters.
- said fiber optic conductor 12 can advantageously comprise some anchoring means, configured to stabilizing and making said conductor 12 fixed with the snowpack, with the terrain or with the ground surface of the slope or declivity 90.
- Said anchoring means can comprise projections or protrusions 80, a corrugated surface 81, formed directly on the outer surface of said fiber optic conductor 12.
- Said anchoring means can also be disks 82 or cantilevered elements applied and fixed to the outer surface of the fiber optic conductor 12 or even gluing materials.
- said anchoring means 12 can also comprise pegs 84, staples or U-bolts suitable for being inserted into the ground.
- avalanche prevention monitoring method 100 and apparatus 10 uses FBG sensors 14 as a means for monitoring the state of the snowpack or of the terrain on a slope or declivity 90 subject to avalanches and landslides, as an advantageous active safety, prevention and alert system to safeguard people and structures.
- the invention operates by advantageously arranging at least one fiber optic conductor 12 in such a way as to arrange the FBG sensors 14 along a line or on a surface or area of a slope or declivity 90 .
- the light signal generated by an optical source or illuminator, advantageously a super- luminescent diode SLED placed in the control unit 20 and subsequently sent through said fiber optic conductor 12 through which it is reflected by the FBG sensors 14, is detected in return by an optical detector placed in the same control unit 20.
- any change of movement of the snowpack or of the terrain of said slope or declivity 90, as well as a change in temperature, pressure or other parameters causes an elongation of the Bragg gratings of the FBG sensors 14 such as the wavelength of the reflected light signal changing.
- This change in wavelength of the return signal is detected by the optical detector then processed and compared by a computer of the control unit 20 with threshold values and other information, so that the output provide information on the state of the snowpack or terrain and preventing avalanches or landslides before they occur in order to secure people, buildings or other structures such as roads, bridges etc.
- the data collected by the control unit 20 can be stored on an internal memory of the same control unit 20 or be sent by known wired or wireless (wireless) transmission means to a remote unit 70 for further processing or for storage.
- said fiber optic conductor 12 can simply be arranged along the surface of the slope or declivity 90 in such a way as to be subsequently wrapped and surrounded by the snowpack.
- the prevention system object of the present invention having advantageously, in addition to sections 12' of conductor in optical fiber 12 parallel to the development of the slope or declivity 90, also of emerging sections 12" of fiber optic conductor 12 which detach from the terrain surface by means of poles 18 in such a way as to be able to arrange FBG sensors 14 in each layer 30, 30', 30", in such a way as to be able to detect the fundamental physical parameters such as temperature, pressure and the relative movements of one layer with respect to the other and, with appropriate processing and comparison with other data and parameters, in order to be able to determine the number of layers, their density and other information.
- the fiber optic conductor 12 can be advantageously provided with anchoring means to the snowpack in such a way as to be fixed with it and detecting the micro displacements of said snowpack even with greater precision.
- an arrangement of the fiber optic conductor 12 on curvilinear and mixed linear non-linear sections, as well as an arrangement of a plurality of fiber optic conductors 12 arranged according to a grid or a matrix 13, advantageously provides a real-time mapping and a three-dimensional state of a surface or area of the slope or declivity 90.
- This mapping which can be all the more defined the greater the number of FBG sensors 14arranged and the smaller the distance between them, can be useful for self-learning, predictive or machine learning systems and algorithms that use amount and accuracy of the data provided by the FBG sensors 14 to determine what types of events or phenomena are occurring on the slope or declivity 90.
- This mapping also allows you to determine if these phenomena can be dangerous and such as to generating avalanches or landslides, such as ground movements and of the layers of the snowpack or parts of thereof, substantial temperature differences between layers 30, 30', 30" of the snowpack, or are potentially non- dangerous phenomena such as wind, rain, passage of animals or people, which can be detected by vibrations or movements of the FBG sensors 14.
- the avalanche and landslide prevention monitoring method 100 and apparatus 10 object of the present invention achieve are evident.
- the avalanche and landslide prevention monitoring method 100 and apparatus 10 is particularly advantageous since it provides the user with an effective monitoring, prevention and active safety system that is extremely simple, easy to install, simple to maintain and low invasiveness and environmental impact, being completely and easily removable.
- a further advantage due to the avalanche and landslide prevention monitoring method 100 and apparatus 10 object of the present invention is that, unlike traditional electrical and electronic systems, FBG sensors 14 are particularly suitable for outdoor applications, in contact with atmospheric agents such as water and humidity and high temperature changes, being insensitive to breakage due to thermal expansion, oxidation and corrosion.
- a further advantage due to the method 100 and to the avalanche and landslide prevention monitoring apparatus 10 object of the present invention is that, unlike traditional electrical and electronic systems, the FBG sensors 14 are completely insensitive to radio and electromagnetic phenomena, which makes it particularly suitable for use in the mountains where electrical discharges due to lightning frequently occur.
- a further advantage of avalanche and landslide prevention monitoring method 100 and apparatus 10 object of the present invention is that they provide the user with a system that can be implemented by means of algorithms and processing software and that are capable of operating in self-learning, predictive or machine learning in such a way as to provide not only a monitoring and prevention system but also a system for the statistical analysis of phenomena.
Landscapes
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geophysics (AREA)
- Geology (AREA)
- Acoustics & Sound (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Testing Or Calibration Of Command Recording Devices (AREA)
- Jib Cranes (AREA)
- Retarders (AREA)
- Air Bags (AREA)
Abstract
An avalanche and landslide prevention monitoring method (100) comprises steps of: - (102) providing at least one fiber optic conductor (12) comprising a plurality of FBG sensors (14), arranged along a slope (90); - (104) providing a light signal at one end of said fiber optic conductor; - (106) acquiring at the input in real time at least one light signal reflected by one or more FBG sensors (14); -(108) processing the wavelength changing signal as a function of the time of the reflected light signal by means of a computer or CPU; (110) obtain three-dimensional maps of state parameters of the snowpack or of the soil as output; - (112) generate an alarm or an imminent avalanche or landslide signal in response to exceeding certain threshold values of the status parameters. The invention also includes an avalanche prevention monitoring apparatus (10) which implements the method (100).
Description
“AVALANCHE AND LANDSLIDES PREVENTION MONITORING SYSTEM
The present invention refers to an avalanche and landslide prevention monitoring system with FBG sensors.
More particularly, the present invention refers to an avalanche and landslide safety prevention system defined by a monitoring method for detecting and analyzing movements and an apparatus for implementing the same method using FBG optical fiber sensors. TECHNICAL BACKTERRAIN
Several systems are known in the art for monitoring and detecting layers movements of the snowpack or terrain on mountain slopes and declivity in order to preventing or otherwise determining the imminent occurrence of an avalanche or landslide. These known systems are generally electrical or electronic type and employ various types of sensors such as accelerometers or seismographs or even detection systems with radio devices or GPS. These devices are typically designed to be inserted into the terrain, in such a way as to be able to detect small displacements of the terrain or of the snow cover as a function of time and with respect to a fixed reference, allowing intervention before the phenomenon occurs and thus preventing its destructive effects.
Some examples of these known applications are described in the patent documents JP H06230101 A andJP 2015175675 A.
However, these known avalanche and landslide prevention systems presents drawbacks and operating limits.
An operational limit of electrical and electronic systems is due to the fact that they have to be powered by an electrical circuit and are therefore sensitive to electrical discharges, which makes them poorly efficient in outdoor use, typically in mountain areas at high altitudes where lightning discharges can frequently occur and in the presence of water or snow.
A further operational limitation is due to the fact that normal electronic detection devices are sensitive to radio and electromagnetic noise and disturbances.
Last but not least limit of these known systems is due to the fact that they are particularly expensive, especially if deployed over long distances.
A further limitation of these traditional detection systems is that they depend on a closed electrical circuit, where the interruption of any part of causes the detection system to fail. Yet a further limitation of these traditional detection systems is that they are poorly resistant to humidity and corrosion caused by weathering.
PURPOSES AND OBJECT OF THE INVENTION
The object of the present invention is to overcome and obviate, at least in part, the above- mentioned drawbacks and operating limits.
More particularly, the object of the present invention is to provide an avalanche and landslide prevention monitoring system with FBG sensors, capable of a constant monitoring, in real time and in remote, of the physical conditions of the snowpack or of the terrain of a slope or declivity.
A further object of the present invention is to provide to the user an avalanche and landslide prevention monitoring system with FBG sensors, capable of detecting in real time any changes in position and temperature of the snowpack or terrain of a slope or declivity, generating an alarm by means of signaling systems.
Still another object of the present invention is to provide an avalanche and landslide prevention monitoring system with FBG sensors, capable of guaranteeing a high level of
resistance and reliability over time and such as to be easily and economically implemented and maintainable.
These and other objects are achieved by the avalanche and landslide prevention monitoring system with FBG sensors object of the present invention in accordance with the independent claims.
With preliminary reference to Figures 2a, 2b and 7, optical fiber sensors FBG ( Fiber Bragg Grating) or FBGs type are known in the state of the art and consisting of a multiplicity of intrinsic sensors arranged directly along the conductive optical fiber medium. Each single FBG sensor is formed by directly etching a periodic diffractive grating, or Bragg grating, into the optical conductive medium (core), which is defined by a series of micro-incisions in the optical fiber configured to function as optical filters of the light signal that reflect or let pass certain wavelengths or colors of the optical spectrum emitted by a light source (LED).
The detection portion of a fiber optic sensor chain is given by FBG segments, typically between 10 and 20 millimeters in length, that can be connected along the fiber optic conductor, exactly in the points where sampling is required.
A single fiber optic conductor can carry a multiplicity of FBG sensors connected in series, significantly reducing weight and space compared to similar sensors based on electrical and electronic technologies, each of which requires dedicated wiring. This feature allows to provide measurement chains with lengths ranging from a few tens of meters to several kilometers and such that they can be easily structured, with an elementary wiring and simple control hardware.
With preliminary reference also to Figure 7, the continuous light signal emitted by a light source, typically a super-luminescent or SLED type, is reflected on predefined wavelengths
by the FBG sensor network and detected in return by a spectrometer. Both hardware components are extremely small in size and weight and have low power consumption.
The hardware incorporated with the FBG network is also extremely small in size and generally includes a SLED unit, the spectrometer and a control computer CPU and various interfaces for connecting to recording storage or data transmission units on site or remotely. External mechanical and physical factors, such as mechanical elongation induced on the fiber optic cable, vibrations, thermodynamic temperature etc. lead to a deformation of the Bragg grating, such as to alter the distance between the micro incisions on the optical fiber and cause a wavelength shift of the reflected light signal. This shift in the wavelength of the reflected light, appropriately calibrated, provides a dynamic measure of the elongation undergone by the fiber optic cable.
The arrangement of a plurality of FBG sensors configured in series along the fiber optic conductor advantageously allows further physical parameters in real time, such as for example temperature, pressure, acceleration. It is therefore evident how a single fiber optic cable can have the functionality of several measuring sensors.
The object of the present invention is that of an optical system that integrates in an innovative way the FBG sensors in an avalanche and landslide prevention monitoring system, in such a way as to advantageously determine the state parameters or the chemical-physical conditions of the snowpack. or of the terrain, which precede these phenomena, in such a way as to prevent their disastrous effect on people or things.
The constructive and functional features of the avalanche and landslide prevention monitoring system with FBG sensors object of the present invention may be better understood from the detailed description that follows, in which reference is made to the attached drawing that represent a preferred and non-limiting embodiment, wherein:
BRIEF DESCRIPTION OF FIGURES
Figure 1 is a schematic representation of a perspective view of the apparatus for implementing the avalanche and landslide preventing monitoring method with FBG sensors object of the present invention arranged on mountain slopes or declivity;
Figure 2a is a schematic representation of a partial view of the optical fiber cable provided with a plurality of FBG sensors of the implementation apparatus of the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention; Figure 2b is a schematic representation in transparency of a detail view of a single FBG sensor of the optical fiber cable of the apparatus for implementing the avalanche and landslide prevention monitoring method object of the present invention;
Figure 3 is a schematic representation of a partially sectioned side view of an embodiment of the apparatus for implementing the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention, with sections of cable and FBG sensors arranged alternately along the direction of the slope or declivity and perpendicular thereto; Figure 4 is a schematic representation of a partially sectioned side view of a further embodiment of the apparatus for implementing the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention, with the cable and the FBG sensors arranged at the below the surface of the slope or declivity;
Figures 5a and 5b are partial schematic representations of detailed views of the fiber optic conductor of the apparatus for implementing the avalanche and landslide prevention monitoring method with FBG sensors object of the present invention, provided with means for anchoring to the snowpack and to the terrain;
Figures 6a and 6b are a schematic representation in perspective view of some examples of geographical arrangement on mountain slopes or declivity of the apparatus for implementing the avalanche and landslide prevention monitoring method with FBG sensors object of the
present invention;
Figure 7 is a schematic representation of the operation of a traditional optical detection or sensing system with the FBG type sensors;
Figure 8 is a schematic representation of a flowchart of the avalanche and landslides prevention monitoring method object of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
With general reference to all the figures and in particular to figure 8, an avalanche and landslide prevention monitoring system with FBG sensors is described below, comprising a method 100 and an apparatus 10 which implements the method 100.
The method 100 for avalanche and landslide prevention monitoring comprising the steps of: 102 providing at least one fiber optic conductor 12 comprising a plurality or array of differently spaced FBG sensors 14 along a snow-covered o landslide-prone slope or declivity 90;
104 providing a light signal to one of the ends of said fiber optic conductor 12, preferably the downstream end, by means of an optical illuminator (not shown) typically arranged in a control unit 20;
106 acquiring as input and in real time at least one light signal reflected by one or more FBG sensors 14 by means of an optical detector (not shown) typically arranged within said control unit 20;
108 processing the time-dependent wavelength changing signal of said at least one reflected light signal, in response to a changing in FBG grating size of said at least one sensor FBG 14, by means of a CPU computer of control unit 20;
110 obtaining at the output a three-dimensional map of the temperatures and 110' obtaining at the output a map of the micro-movements, vibrations or accelerations of the snowpack or of the terrain as a result of said step 108 of processing the signal
of the wavelength changing of said at least a reflected light signal;
122 comparing the values of said three-dimensional map of temperatures and of said map of micro-movements, vibrations and accelerations of the snowpack or of the terrain with threshold values or reference parameters or supplementary data; - 112 in response to the exceeding of certain threshold values of the physical state parameters of the snowpack or of the terrain with the possible creation of alarm and warning scenarios.
The method 100 can comprise in succession to step 102 the further step of: providing a plurality of fiber optic conductors 12 comprising a plurality of FBG sensors 14 arranged to define a grid or a matrix 13 arranged on a surface or area of a slope or declivity 90.
With particular reference again to Figure 8, the avalanche and landslide prevention monitoring method 100 may also comprise, before step 122 comparing the values of said three-dimensional map of temperatures, micro-movements, vibrations and accelerations with threshold values of reference parameters or supplementary data, the acquisition of additional supplementary and complementary data from different sources with further steps of:
116 generating a three-dimensional map and determine the orographic characteristics of the terrain of the slope and declivity 90 with a geolocation of the FBG 14 sensors by means of known techniques such as stereoscopic photographs or topographic measurements by means of radio-satellite GPS devices, said three-dimensional mapping being provided , in the case of a snow-covered slope or declivity 90, of a resolution preferably in the order of magnitude of one decimeter [dm];
118 generate a three-dimensional map of the FBG sensors 14 distinguishing between their type and functionality on the three-dimensional terrain map and;
118' generate a three-dimensional map of the snowpack pressures on said slope or declivity 90 per centimeter [cm] of snow, 3D model of gravitational forces as a function of snowfall and any other parameters such as percentage humidity, accelerations etc. of snowpack or terrain; - 118" generate a map of the distribution of vegetation and additional complementary characteristics such as friction, thermal conductivity and composition of the materials constituting the terrain or present on the ground of the slope and declivity 90.
The step 108 of processing the wavelength changing signal as a function of time of said at least one reflected light signal can be preceded by a step of: - 120 filtering of the acquired data with known sampling algorithms and extracting of significant events, such as moving averages etc., of data on localized and non- localized vibrations, terrain movements, percentage humidity changes etc., so as to reduces the amount of data, handling and speeding up the processing of the control unit 20 while maintaining an acceptable data approximation. The step 108 of processing the wavelength changing signal as a function of time of said at least one reflected light signal may comprise a step of:
108' interpolating the data acquired by the FBG sensors 14 by means of known linear or non-linear interpolation mathematical algorithms, in such a way as to obtain a homogeneous and statistically correct three-dimensional map also of the parameters of the points placed between two or more adjacent FBG sensors 14;
Step 122 of comparing the values of said three-dimensional map of temperatures and of said map of micro-movements, vibrations or accelerations of the snowpack or of the terrain with threshold values of benchmarks parameters or integrative data may comprise an operation of; generating one or more event predictive algorithms by means of known machine
learning techniques, statistical analysis and neuronal networks.
Said step 122 of comparing the values of said three-dimensional map of temperatures and of said map of micro-movements, vibrations or accelerations of the snowpack or of the terrain may also be preceded by further data integration steps:
121 using theoretical models of dynamic snow / terrain interactions on the basis of standard parameters and sampled data;
126 acquiring meteorological data by means of traditional meteorological stations placed near said snow-covered slope or declivity 90;
128 acquiring meteorological data by means of satellite meteorological systems;
130 determining environmental parameters of the slope or declivity 90 such as geographical location, altitude, exposure to sunlight etc.;
132 integrating a surface temperatures map with data detected by means of one or more infrared IR cameras arranged in a position facing the surface of the snowpack of the slope or declivity 90, said IR cameras being advantageously arranged on an opposite slope or on poles 18.
Said phase 122 of comparing the values of said three-dimensional temperatures map and of said map of micro-movements, vibrations or accelerations of the snowpack or of the terrain, can also be preceded and followed by a step of:
124 creating a data archive or database for locally or remotely storing the results. With particular reference now to Figures 6a and 6b, the arrangement of multiplicity of fiber optic conductors 12 comprising FBG sensors 14 and arranged in such a way as to form a grid or a matrix 13, has the important and innovative advantage of being able to cover an area or surface of the slope or declivity 90 and to monitor or punctually mapping the physical conditions of the snowpack or terrain at each point of the grid or matrix 13. The greater the number of FBG sensors 14, the shorter the distance between them and the higher the
resolution and homogeneity of the map of the detected parameters.
The step 110 obtaining at the output a three-dimensional map of the temperatures and 110' obtaining at the output a map of the micro-movements, vibrations or accelerations of the snowpack or of the terrain as a function of the comparison with threshold values of reference parameters can comprise the determination of a relative length to the elongation or deformation of the fiber optic conductor 14, so as to function as a strain sensor.
The step 110 of obtaining at the output a three-dimensional map of the temperatures and 110' obtaining at the output a map of the micro-movements, vibrations or accelerations of the snowpack or of the terrain as a function of the comparison with threshold values of reference parameters can also comprise, for certain FBG sensors 14, determining other further physical parameters of the snowpack or of the terrain such as thermodynamic temperature, pressure, acceleration, vibrations applied to the fiber optic conductor 12.
The step 102 of providing at least one fiber optic conductor 12 comprising a plurality of FBG sensors 14, arranged along a slope or declivity 90 can comprise further steps of:
- arranging at least a portion of fiber optic conductor 12 comprising a plurality of FBG sensors 14 arranged along the direction of the slope or declivity 90 or of descent of the avalanche or landslide and
- arranging at least a portion of fiber optic conductor 12 comprising a plurality of FBG sensors 14 arranged in a substantially perpendicular direction, along the direction of the force of gravity or in any case not along the direction of the slope or declivity 90 by means of poles 18.
With particular reference to Figure 3, the arrangement of a portion of fiber optic conductor 12 with FBG sensors 14 in a substantially perpendicular direction or along the direction of the force of gravity or in any case not along the direction of the slope or declivity 90 or of natural descent of the avalanche or landslide, has the important advantage of being able to
have FBG sensors 14 in each single overlapping layer of snow at different densities, accumulated on said slope or declivity 90, thus allowing a detection of the parameters relating to each single layer of snow as well as to determination itself of the number of layers subsequently overlapped. With reference to Figures 5a and 5b, the step 102 of providing at least one fiber optic conductor 12 comprising a plurality of FBG sensors 14 arranged along a slope or declivity 90, can further comprise a step of:
- providing means for anchoring said fiber optic conductor 12 comprising FBG sensors 14 to the snowpack or to the terrain. Since the fiber optic conductor 12 is a circular section cable, generally smooth on the surface and without any roughness, in order to better detect the movements of the snowpack or of the terrain it can advantageously be provided with means for anchoring the outer surface with the snow or on the terrain or soil or rock, such as for example projections or protrusions 80, corrugations 81, disks 82, as shown as example in Figure 5a. Said anchoring means are suitable for making the fiber optic conductor 12 integral with the snowpack or can be pegs 84, staples or other known types of gluing, suitable for stabilizing the fiber optic conductor 12 to the terrain so as to make it integral with the same in the movements, as shown as example in figure 5b.
With initial reference to Figures 1 and 2, it is also an object of present invention to provide an avalanches and landslides prevention monitoring apparatus 10 comprising: at least one fiber optic conductor 12, generally a traditional circular cross-sectional cable having a transmitting optical core 15 and a protective coating 16, comprising a plurality of FBG sensors 14 formed in said core 14 by means of incisions 14 1 defining a Bragg grating, said conductor 12 being suitable to be arranged along the snow-covered surface or landslide- prone slope or declivity 90 and connected at one end thereof;
a control unit 20 comprising an optical illuminator (not shown) configured to sending an optical signal through said fiber optic conductor 12, and comprising an optical receiver (not shown) configured to receiving a return light signal from said fiber optic conductor, said control unit 20 comprising a computer or CPU being configured to:
- processing a time dependent wavelength changing signal of said at least one reflected light signal acquired by said at least one FBG sensor;
- obtaining at the output of the state parameters or parameters maps of the snowpack or of the terrain;
- comparing said state parameters with threshold values of reference parameters or supplementary data;
- generating an alarm signal in response to the exceeding of certain threshold values of the state parameters of the snowpack or of the terrain.
Said fiber optic conductor 12 is generally arranged, in a simple embodiment, along the shortest linear descent direction of the slope or declivity 90, but it can also be arranged according to other directions, to also form complex curvilinear or mixed-linear sections, such as for example a wavy line, in order to arrange a greater number of FBG sensors 14 on the surface of said slope or declivity 90.
With particular reference to figure 4, in the case in which the apparatus 10 is configured to function as a monitoring system against landslides, said fiber optic conductor 12 can also be arranged under the terrain surface of said slope or declivity 90.
The apparatus can also advantageously comprise a plurality of fiber optic conductors 12 provided with FBG 14 sensors, arranged to define a grid or array 13 of FBG sensors 14arranged to cover a surface or area (or a portion thereof), of a slope or declivity 90.
Said FBG sensors 14 are arranged in series along the same fiber optic conductor 12 and can
be uniformly or differently spaced from each other in such a way as to define portions or portions of the fiber optic conductor 12 more or less dense than FBG sensors 14.
A plurality of optical fiber sensors 12 can also advantageously be collected in a bundle or cable of independently illuminated conductors and able to branch and separate along their development in such a way as to be able to selectively arrange themselves in the different zones or areas where the presence of sensors FBG 14 where sampling is needed.
Said FBG sensors 14 can also be differently configured, independently of one another, in such a way that each can function as:
- a strain sensor configured to sensing or detecting (measuring) a length displacement;
- a temperature sensor configured to detect a temperature; a pressure sensor configured to determine a pressure acting on the external surface of the sensor FBG;
- an accelerometer or seismograph configured to detecting a change in the speed of movement of the fiber optic conductor 12.
With particular reference to Figure 3, in an embodiment configured to function as an avalanche prevention monitoring system, the apparatus 10 can advantageously comprise at least a or a parallel section 12', of said fiber optic conductor 12 comprising a multiplicity of sensors FBG 14, arranged along the direction of the slope or declivity 90 and comprising at least a portion or emerging section 12" of fiber optic conductor 12 comprising a plurality of sensors FBG 14, said portion or emerging section being preferably arranged in a substantially perpendicular direction , or in any case not parallel to the direction of the slope, by means of poles 18 fixed in the terrain of the slope or declivity 90 in a substantially perpendicular way, as in the example of figure 3, or along the vertical line of direction of gravity . Said poles 18 can be made of any suitable structural material such as for example metal, wood, polymeric materials, concrete or equivalent. Said poles 18 can also be advantageously provided with fixing and supporting means (not shown) of the fiber optic conductor 12 such as for example
eyelets, openings or support brackets suitable for allowing the support and movement of said fiber optic conductor 12 avoiding its damage.
Said poles 18 can also be advantageously provided with visual means, for example can be colored, in order to be easily identifiable on the surface of the snow.
This solution allows the emerging sections 12" of said fiber optic conductor 12 to cross with the relative FBG sensors 14 a plurality of possible layers 30, 30', 30" of the snowpack, having different chemical-physical characteristics, which can settle on the slope or declivity 90, in such a way as to arrange at least one FBG sensor 14 inside each layer 30, 30', 30" and, possibly, also at least one FBG 14 sensor in contact with the atmosphere environment.
Said parallel section 12' and said emerging section 12" of the fiber optic conductor 12 can also be advantageously configured in such a way as to arrange a different number of FBG sensors 14 on each portion, with different distance between them and configured in such a way to reveal or measure different quantities or physical parameters.
Referring again to all the figures and in particular to figure 5, in any embodiment of the apparatus 10, configured to function both as an avalanche prevention monitoring system and as a landslide prevention monitoring system, said fiber optic conductor 12 can advantageously comprise some anchoring means, configured to stabilizing and making said conductor 12 fixed with the snowpack, with the terrain or with the ground surface of the slope or declivity 90. Said anchoring means can comprise projections or protrusions 80, a corrugated surface 81, formed directly on the outer surface of said fiber optic conductor 12. Said anchoring means can also be disks 82 or cantilevered elements applied and fixed to the outer surface of the fiber optic conductor 12 or even gluing materials.
To fix said fiber optic conductor 12 to the terrain, said anchoring means 12 can also comprise pegs 84, staples or U-bolts suitable for being inserted into the ground.
From the description of the avalanche and landslide prevention monitoring method 100 and
apparatus 10 object of the present invention, is evident the operation described below.
With reference to the aforementioned figures, avalanche prevention monitoring method 100 and apparatus 10, object of the present invention, uses FBG sensors 14 as a means for monitoring the state of the snowpack or of the terrain on a slope or declivity 90 subject to avalanches and landslides, as an advantageous active safety, prevention and alert system to safeguard people and structures.
With reference to the figures and in particular to figure 1, the invention operates by advantageously arranging at least one fiber optic conductor 12 in such a way as to arrange the FBG sensors 14 along a line or on a surface or area of a slope or declivity 90 .
The light signal, generated by an optical source or illuminator, advantageously a super- luminescent diode SLED placed in the control unit 20 and subsequently sent through said fiber optic conductor 12 through which it is reflected by the FBG sensors 14, is detected in return by an optical detector placed in the same control unit 20.
Any change of movement of the snowpack or of the terrain of said slope or declivity 90, as well as a change in temperature, pressure or other parameters causes an elongation of the Bragg gratings of the FBG sensors 14 such as the wavelength of the reflected light signal changing. This change in wavelength of the return signal is detected by the optical detector then processed and compared by a computer of the control unit 20 with threshold values and other information, so that the output provide information on the state of the snowpack or terrain and preventing avalanches or landslides before they occur in order to secure people, buildings or other structures such as roads, bridges etc.
The data collected by the control unit 20 can be stored on an internal memory of the same control unit 20 or be sent by known wired or wireless (wireless) transmission means to a remote unit 70 for further processing or for storage.
In operation as avalanche prevention system, with particular reference to Figure 3, said fiber
optic conductor 12 can simply be arranged along the surface of the slope or declivity 90 in such a way as to be subsequently wrapped and surrounded by the snowpack.
However, since it is well known that avalanche and slide phenomena generally occur due to the sliding of one or more layers 30, 30', 30" of the snowpack, the prevention system object of the present invention having advantageously, in addition to sections 12' of conductor in optical fiber 12 parallel to the development of the slope or declivity 90, also of emerging sections 12" of fiber optic conductor 12 which detach from the terrain surface by means of poles 18 in such a way as to be able to arrange FBG sensors 14 in each layer 30, 30', 30", in such a way as to be able to detect the fundamental physical parameters such as temperature, pressure and the relative movements of one layer with respect to the other and, with appropriate processing and comparison with other data and parameters, in order to be able to determine the number of layers, their density and other information.
In this case also the fiber optic conductor 12 can be advantageously provided with anchoring means to the snowpack in such a way as to be fixed with it and detecting the micro displacements of said snowpack even with greater precision.
With particular reference also to Figures 6a and 6b, an arrangement of the fiber optic conductor 12 on curvilinear and mixed linear non-linear sections, as well as an arrangement of a plurality of fiber optic conductors 12 arranged according to a grid or a matrix 13, advantageously provides a real-time mapping and a three-dimensional state of a surface or area of the slope or declivity 90.
This mapping, which can be all the more defined the greater the number of FBG sensors 14arranged and the smaller the distance between them, can be useful for self-learning, predictive or machine learning systems and algorithms that use amount and accuracy of the data provided by the FBG sensors 14 to determine what types of events or phenomena are occurring on the slope or declivity 90. This mapping also allows you to determine if these
phenomena can be dangerous and such as to generating avalanches or landslides, such as ground movements and of the layers of the snowpack or parts of thereof, substantial temperature differences between layers 30, 30', 30" of the snowpack, or are potentially non- dangerous phenomena such as wind, rain, passage of animals or people, which can be detected by vibrations or movements of the FBG sensors 14.
As can be seen from the foregoing, advantages that the avalanche and landslide prevention monitoring method 100 and apparatus 10 object of the present invention achieve are evident. The avalanche and landslide prevention monitoring method 100 and apparatus 10 is particularly advantageous since it provides the user with an effective monitoring, prevention and active safety system that is extremely simple, easy to install, simple to maintain and low invasiveness and environmental impact, being completely and easily removable.
A further advantage due to the avalanche and landslide prevention monitoring method 100 and apparatus 10 object of the present invention is that, unlike traditional electrical and electronic systems, FBG sensors 14 are particularly suitable for outdoor applications, in contact with atmospheric agents such as water and humidity and high temperature changes, being insensitive to breakage due to thermal expansion, oxidation and corrosion.
A further advantage due to the method 100 and to the avalanche and landslide prevention monitoring apparatus 10 object of the present invention is that, unlike traditional electrical and electronic systems, the FBG sensors 14 are completely insensitive to radio and electromagnetic phenomena, which makes it particularly suitable for use in the mountains where electrical discharges due to lightning frequently occur.
A further advantage of avalanche and landslide prevention monitoring method 100 and apparatus 10 object of the present invention is that they provide the user with a system that can be implemented by means of algorithms and processing software and that are capable of operating in self-learning, predictive or machine learning in such a way as to provide not only
a monitoring and prevention system but also a system for the statistical analysis of phenomena.
Although the invention has been above described with particular reference to a preferred embodiment, which is given for illustrative and non-limiting purposes, numerous modifications and changings will appear obvious to a person skilled in the art in the light of the above description. The present invention, therefore, intends to embrace all the modifications and changings that falling within the scope of the following claims.
Claims
1. An avalanche and landslide prevention monitoring method (100) comprising the steps of:
(102) providing at least one fiber optic conductor (12) comprising a plurality of FBG sensors (14), arranged along a slope or declivity (90) that snow-covered or subject to landslides;
(104) providing a light signal at one end of said fiber optic conductor (12) by means of an optical source;
(106) acquiring at the input in real time at least one light signal reflected by one or more FBG sensors (14) by means of an optical detector;
(108) processing the wavelength changing signal as a function of time of said at least one reflected light signal, in response to a changing in the FBG grating size of said at least one sensor FBG (14) by means of a computer or CPU;
(110) obtaining at the output a three-dimensional map of the temperatures, and (110') obtaining at the output a map of the micro-movements, vibrations or accelerations of the snowpack or of the terrain, as a result of said step 108 of processing the signal wavelength changings of said at least one reflected light signal;
(112) generate an alarm or an imminent avalanche or landslide signal in response to the exceeding of certain threshold values of the snowpack or terrain state parameters.
2. The method (100) according to claim 1, wherein the step (102) of providing at least one fiber optic conductor (12) with a plurality of FBG sensors (14), further comprises the step of providing a plurality of fiber optic conductors (12) comprising a plurality of FBG sensors (14) arranged to define a grid or a matrix (13) disposed on a surface or area of a snow-covered slope or declivity (90).
3. The method according to claim 1, wherein the step (108) of processing the wavelength changing signal is preceded by a step of:
(120) filtering of the acquired data with sampling algorithms and extraction of significant data events, so as to reduce the amount of data, handling and speeding up the processing of the control unit (20) while maintaining an acceptable data approximation.
4. The method according to claim 1, wherein the step (108) of processing the wavelength changing signal is preceded by a step of:
(108') interpolating the data acquired by the FBG sensors (14) by means of linear or non-linear interpolation mathematical algorithms, in such a way as to obtain a homogeneous and statistically correct three-dimensional map of the parameters of the points placed between two or more adjacent sensors FBG (14).
5. The method according to claim 1, wherein the step (122) of comparing the values of said three-dimensional map of temperatures and of said map of the micro -movements, vibrations or accelerations of the snowpack or of the terrain comprises an operation of; generating one or more event predictive algorithms by means of machine learning techniques, statistical analysis and neuronal networks.
6. The method according to claim 1, wherein step (102) to provide at least one fiber optic conductor (12) comprising a multiplicity of FBG sensors (14), arranged along a snow-covered slope or declivity (90) comprises the step of: providing at least a portion of the fiber optic conductor (12) comprising a plurality of FBG sensors (14) arranged in the direction of the slope or declivity (90) and providing at least a portion of the fiber optic conductor (12) comprising a multiplicity of FBG sensors (14) arranged in a direction substantially perpendicular to the direction of the slope or declivity (90) by means of poles (18).
7. The method according to claim 1, wherein step (102) of providing at least one fiber optic conductor (12) comprising a plurality of FBG sensors (14), arranged along a snow- covered slope or declivity (90) comprises the step of: providing means of anchoring to the snowpack or the ground of this fiber optic conductor (12).
8. An avalanche and landslide prevention monitoring apparatus (10) comprising: a fiber optic conductor (12) comprising a plurality of FBG sensors 14, said fiber optic conductor (12) being suitable for be arranged along the surface of a snow-covered or landslides-prone slope or declivity (90) and be connected at one end to; a control unit (20) comprising an optical source and suitable for sending an optical signal through this fiber optic conductor (12); an optical receiver suitable for receiving a return light signal from said fiber-optic conductor, said control unit (20) comprising a computer or CPU, and said control unit (20) being configured to processing a wavelength signal changing as a time function of said at least one reflected light signal acquired by at least one FBG sensor (14) in order to: obtaining status parameters or maps of snowpack or ground parameters at the output; compare said status parameters with threshold values of reference parameters or supplementary data; generate an alarm signal in response to the exceeding of certain threshold values of snowpack or terrain parameters.
9. The apparatus (10) according to claim 8, comprising a plurality of fiber optic conductors
(12) provided with FBG sensors (14), arranged in such a way as to define a grid or matrix
(13) of FBG sensors (14).
10. The apparatus (10) according to claim 8, wherein said FBG sensors (14) of said fiberoptic conductor (12) are arranged in series along the same fiber optic conductor (12) and can be uniformly or differently spaced.
11. The apparatus (10) according to claim 8, wherein said FBG sensors (14) can also be configured independently of each other in such a way that each of them can function as a strain sensor, temperature sensor, pressure sensor, accelerometer or seismograph.
12. Apparatus (10) according to claim 8, comprising at least one parallel section (12') of said fiber optic conductor (12) arranged along the direction of the slope or declivity (90) and comprising at least one emerging section (12') arranged in a direction not parallel to the direction of said slope or declivity (90) by means of poles (18) fixed in the ground of the same slope or declivity (90).
13. The apparatus (10) according to claim 12, wherein said emerging sections (12") of the 20 fiber optic conductor (12) are configured to define a different number of FBG sensors(14) on each section, with different distances between them, and are configured in order to detect or measure different quantities or physical parameters.
14. The apparatus (10) according to claim 8, wherein said fiber optic conductor (12) comprises means of anchorage suitable to stabilize and make the fiber optic conductor fixed with the snowpack, with the ground or with the surface of said slope or declivity (90). 15. Apparatus (10) according with claim 14, wherein said means of anchoring comprising projecting parts or protrusions (80) or a corrugated surface (81) formed directly on the outer surface of said fiber optic conductor (12) or comprising disks (82) applied and fixed to the outer surface of said fiber optic conductor (12).
16. The apparatus (10) according to claim 14, wherein said means of anchoring comprising 10 stakes, clips, or U-bolts suitable for being inserted into the terrain in order to stabilize
said fiber optic conductor (12).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP21734207.0A EP4158281A1 (en) | 2020-05-25 | 2021-05-24 | Avalanche and landslides prevention monitoring system with fbg sensors |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT102020000012223 | 2020-05-25 | ||
IT102020000012223A IT202000012223A1 (en) | 2020-05-25 | 2020-05-25 | ANTI-AVALANCHE AND LANDSLIPS MONITORING SYSTEM WITH FBG SENSORS |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2021240338A1 true WO2021240338A1 (en) | 2021-12-02 |
Family
ID=72086990
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2021/054482 WO2021240338A1 (en) | 2020-05-25 | 2021-05-24 | Avalanche and landslides prevention monitoring system with fbg sensors |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP4158281A1 (en) |
IT (1) | IT202000012223A1 (en) |
WO (1) | WO2021240338A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114754692A (en) * | 2022-03-21 | 2022-07-15 | 蚌埠学院 | Fiber grating type sensor and fiber grating type sensing system |
CN116242238A (en) * | 2023-04-28 | 2023-06-09 | 山东鲁地建设发展有限公司 | Landslide monitoring device for ecological restoration of mine |
CN117268475A (en) * | 2023-11-21 | 2023-12-22 | 深圳市城市交通规划设计研究中心股份有限公司 | Slope safety assessment method based on multidimensional parameter data fusion |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN115526108B (en) * | 2022-10-11 | 2024-01-16 | 重庆地质矿产研究院 | Landslide stability intelligent dynamic prediction method based on multisource monitoring data |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1043565A2 (en) * | 1999-03-31 | 2000-10-11 | Martin Dr. Schreck | Method for controlling the inclination of a terrain |
CN101667327A (en) * | 2008-09-03 | 2010-03-10 | 中国石油天然气股份有限公司 | Method and system for monitoring and warning pipeline landslide depth displacement and method for constructing system |
CN107665570A (en) * | 2017-11-20 | 2018-02-06 | 水禾测绘信息技术有限公司 | A kind of expressway disasters monitoring and warning system |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06230101A (en) | 1993-02-05 | 1994-08-19 | Masanari Togasaka | Detector for avalanche, landslide and the like |
JP2015175675A (en) | 2014-03-14 | 2015-10-05 | 公益財団法人鉄道総合技術研究所 | avalanche detection system |
-
2020
- 2020-05-25 IT IT102020000012223A patent/IT202000012223A1/en unknown
-
2021
- 2021-05-24 WO PCT/IB2021/054482 patent/WO2021240338A1/en unknown
- 2021-05-24 EP EP21734207.0A patent/EP4158281A1/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1043565A2 (en) * | 1999-03-31 | 2000-10-11 | Martin Dr. Schreck | Method for controlling the inclination of a terrain |
CN101667327A (en) * | 2008-09-03 | 2010-03-10 | 中国石油天然气股份有限公司 | Method and system for monitoring and warning pipeline landslide depth displacement and method for constructing system |
CN107665570A (en) * | 2017-11-20 | 2018-02-06 | 水禾测绘信息技术有限公司 | A kind of expressway disasters monitoring and warning system |
Non-Patent Citations (4)
Title |
---|
HONG-HU ZHU ET AL: "FBG-Based Monitoring of Geohazards: Current Status and Trends", SENSORS, vol. 17, no. 3, 24 February 2017 (2017-02-24), pages 452, XP055766218, DOI: 10.3390/s17030452 * |
LUCA SCHENATO: "A Review of Distributed Fibre Optic Sensors for Geo-Hydrological Applications", APPLIED SCIENCES, vol. 7, no. 9, September 2017 (2017-09-01), pages 896, XP055590600, ISSN: 2076-3417, DOI: 10.3390/app7090896 * |
M WOERNDL ET AL: "Fiber Optic Distributed Temperature Sensing in Avalanche Researc", 2010 INTERNATIONAL SNOW SCIENCE WORKSHOP, May 2010 (2010-05-01), XP055766430, Retrieved from the Internet <URL:https://www.researchgate.net/profile/Jeff_Dozier/publication/252653832_Fiber_Optic_Distributed_Temperature_Sensing_in_Avalanche_Research/links/540886930cf2187a6a697cbf/Fiber-Optic-Distributed-Temperature-Sensing-in-Avalanche-Research.pdf> [retrieved on 20210119] * |
TEUFELSBAUER ET AL: "Linking laser scanning to snowpack modeling: Data processing and visualization", COMPUTERS & GEOSCIENCES, PERGAMON, AMSTERDAM, NL, vol. 35, no. 7, July 2009 (2009-07-01), pages 1481 - 1490, XP026152634, ISSN: 0098-3004, [retrieved on 20090206], DOI: 10.1016/J.CAGEO.2008.10.006 * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114754692A (en) * | 2022-03-21 | 2022-07-15 | 蚌埠学院 | Fiber grating type sensor and fiber grating type sensing system |
CN114754692B (en) * | 2022-03-21 | 2023-06-27 | 蚌埠学院 | Fiber bragg grating sensor and fiber bragg grating type sensing system |
CN116242238A (en) * | 2023-04-28 | 2023-06-09 | 山东鲁地建设发展有限公司 | Landslide monitoring device for ecological restoration of mine |
CN117268475A (en) * | 2023-11-21 | 2023-12-22 | 深圳市城市交通规划设计研究中心股份有限公司 | Slope safety assessment method based on multidimensional parameter data fusion |
CN117268475B (en) * | 2023-11-21 | 2024-03-26 | 深圳市城市交通规划设计研究中心股份有限公司 | Slope safety assessment method based on multidimensional parameter data fusion |
Also Published As
Publication number | Publication date |
---|---|
EP4158281A1 (en) | 2023-04-05 |
IT202000012223A1 (en) | 2021-11-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2021240338A1 (en) | Avalanche and landslides prevention monitoring system with fbg sensors | |
Zeni et al. | Brillouin optical time-domain analysis for geotechnical monitoring | |
CN100487386C (en) | Multi-parameter detector based on composite optical fiber device | |
Lienhart | Case studies of high-sensitivity monitoring of natural and engineered slopes | |
WO2012114077A2 (en) | Distributed acoustic sensing | |
JP2018195111A (en) | Slope collapse early warning system | |
Liu et al. | Fiber-optic wireless sensor network using ultra-weak fiber Bragg gratings for vertical subsurface deformation monitoring | |
KR101845475B1 (en) | Slope safety management system | |
Moore et al. | Rockslide deformation monitoring with fiber optic strain sensors | |
Wu et al. | Development of a monitoring and warning system based on optical fiber sensing technology for masonry retaining walls and trees | |
JP2015145592A (en) | Soil state monitoring system and soil state monitoring method | |
Purnomo et al. | Landslide early warning system based on arduino with soil movement and humidity sensors | |
CN103177531B (en) | Along Railway mud-stone flow disaster is monitored | |
Novotný et al. | Critical Infrastructure Monitoring System | |
Karthik et al. | Review on low-cost wireless communication systems for slope stability monitoring in opencast mines | |
KR101584963B1 (en) | Appratus and method for prediction of collapse symptom of slope using GPS | |
CN116124025A (en) | Deformation monitoring system and method based on distributed optical fiber or array grating optical fiber | |
KR101282478B1 (en) | Sensing device for change of ground surface | |
Lienhart et al. | Reinforced earth structures at Semmering base tunnel—construction and monitoring using fiber optic strain measurements | |
CN202662131U (en) | Mud-rock flow calamity monitoring along railway line | |
KR102154725B1 (en) | Mountain land disaster detection system | |
KR100936813B1 (en) | System and method of measuring ground movement | |
Kashaganova et al. | Fiber sensors based on the Bragg gratings in security systems | |
Gischig | Kinematics and failure mechanisms of the Randa rock slope instability (Switzerland) | |
Inaudi | Overview of fiber optic sensing technologies for structural health monitoring |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 21734207 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 2021734207 Country of ref document: EP Effective date: 20230102 |