Geological disaster monitoring system

Abstract

The invention discloses a geological disaster monitoring system in the field of geological disaster monitoring, and the system comprises a sensor module, a slope protection structure monitoring module, an alarm device, a data processing and transmission module, and a power management module. The slope protection structure monitoring module is used for synchronously monitoring the stability of a slope protection structure, the alarm device is used for quickly warning when geological disasters occur, the data processing and transmission module is used for analyzing and transmitting monitoring data in real time, and the power management module is used for providing continuous power supply for the system. The vibration sensor and the displacement sensor are combined to provide comprehensive monitoring data, the camera provides real-time images to enhance the monitoring effect, and the networking alarm device and the helium balloon are designed to quickly transmit alarm information; the folding structure design is convenient to carry and arrange and suitable for emergency use, and the solar cell panel and the standby cell are adopted to ensure continuous work of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of geological disaster monitoring, and specifically relates to a geological disaster monitoring system. BACKGROUND

[0002] Geological disasters (such as debris flow, landslide, etc.) have the characteristics of strong burst and large destructive, which seriously threaten the safety of people's life and property. At present, the main problems of geological disaster monitoring technology are as follows:

[0003] 1) Single monitoring means: the existing technology mainly uses single sensor (such as vibration sensor or displacement sensor), the monitoring data is not comprehensive enough, and it is difficult to accurately predict the occurrence of geological disasters.

[0004] 2) Insufficient real-time: the data transmission speed of traditional monitoring system is slow, which cannot realize real-time early warning, resulting in lag of emergency response.

[0005] 3) Limited alarm mode: the existing alarm device is mostly fixed, with limited warning range, and it is difficult to set up in remote areas.

[0006] 4) Unstable energy supply: the monitoring system mostly depends on external power supply, and cannot work normally under power failure or adverse weather conditions.

[0007] In view of the above problems, although the existing technology attempts to improve by increasing the number of sensors or optimizing the communication protocol, it does not solve the fundamental problem from the perspective of collaborative innovation of multi-sensor data fusion algorithm, portable alarm device structure and energy management system. Therefore, the technical personnel in the field provide a geological disaster monitoring system to solve the problems raised in the above background technology. SUMMARY

[0008] The purpose of the present application is to provide a geological disaster monitoring system to solve the problems raised in the above background technology.

[0009] To achieve the above purpose, the present application provides the following technical scheme:

[0010] A geological disaster monitoring system, comprising a sensor module, a slope protection structure monitoring module, an alarm device, a data processing and transmission module, and a power management module, the sensor module is used for real-time monitoring of geological disasters, the slope protection structure monitoring module is used for synchronous monitoring of the stability of the slope protection structure, the alarm device is used for rapid warning when a geological disaster occurs, the data processing and transmission module is used for real-time analysis and transmission of monitoring data, and the power management module is used for providing continuous power supply for the system, the sensor module comprises a vibration sensor, a displacement sensor, and a data fusion algorithm module, the slope protection structure monitoring module comprises vibration sensors and displacement sensors matched with the slope protection structure, a high-definition camera, and an image processing module, the alarm device comprises a networked alarm device and a rapidly inflatable helium balloon, the data processing and transmission module comprises a data processing unit and a data transmission unit, and the power management module comprises a solar panel and a backup battery;

[0011] The vibration sensor in the sensor module is used for detecting ground vibration in the monitoring area, and the sensitivity thereof can be adjusted, and the detection frequency range is 0.1 Hz to 100 Hz; the displacement sensor is used for measuring ground displacement changes in the monitoring area, and the measurement accuracy is ±0.1 mm, and the maximum range is ±500 mm; the vibration sensor and the displacement sensor process monitoring data through a data fusion algorithm, and the data fusion algorithm is as follows:

[0012] Df=α·Dv+(1-α)·Dd

[0013] Wherein, Df is the fused data, Dv is the vibration sensor data, Dd is the displacement sensor data, and a is the weight coefficient, and the value range is 0.5 to 0.8;

[0014] The vibration sensor and the displacement sensor in the slope protection structure monitoring module are used for monitoring the vibration and displacement of the slope protection structure; the high-definition camera is equipped with a wide-angle lens and a night vision function, and is used for acquiring image data of the monitoring area in real time; the image processing unit is used for real-time analysis of the image collected by the camera, and adopts an edge detection algorithm to identify cracks and deformation of the slope protection structure, and the edge detection algorithm is as follows:

[0015]

[0016] Wherein, E(x,y) is the edge strength, Gx and Gy are horizontal and vertical gradient operators respectively, and I(x,y) is the image pixel value;

[0017] The networking alarm device in the alarm device is connected with a traffic warning light and other alarm devices, adopts a LoRa or NB-IoT communication protocol, and is used for quickly transmitting alarm information; a helium balloon in the quickly inflatable helium balloon is hung below a light-emitting warning sign, adopts a high-brightness LED light source, the surface of the warning sign is coated with a reflective material, and is used for airborne warning; the alarm device is of a folding structure, is made of light-weight high-strength materials, and is convenient to carry and lay out.

[0018] The data processing unit in the data processing and transmission unit is provided with an artificial intelligence algorithm, which is used for deep analysis of the data of the vibration sensor and the displacement sensor, the artificial intelligence algorithm is an LSTM neural network model based on a time sequence, and the prediction formula is:

[0019] h t =σ(W h ·[h t -1,hx t ]+b h )

[0020] Wherein, h t is a hidden state at the current moment, W h is a weight matrix, b h is a bias term, sigma is an activation function, and x t is input data at the current moment.

[0021] The data transmission unit supports 4G, 5G and satellite communication, and is used for transmitting monitoring data and alarm information to a monitoring center in real time.

[0022] The solar cell panel in the power management module is provided with a maximum power point tracking (MPPT) algorithm, which is used for supplying power to the system during the day, and the MPPT algorithm is:

[0023] P max =V mp ·I mp

[0024] Wherein, P max is the maximum power, V mp and I mp are the voltage and current corresponding to the maximum power point respectively.

[0025] The standby battery adopts a lithium ion battery and is provided with an electric quantity monitoring function, can display the residual electric quantity in real time, and gives a warning when the electric quantity is insufficient.

[0026] As a further scheme of the application, the data acquisition frequency of the vibration sensor and the displacement sensor is adjustable, so as to adapt to the monitoring requirements of different geological environments, and the data acquisition frequency range is 1Hz to 100Hz.

[0027] As a further scheme of the present application: the high-definition camera is equipped with automatic focusing and anti-shake functions, and can obtain clear monitoring images in adverse weather conditions.

[0028] As a further scheme of the present application: the surface of the helium balloon of the alarm device is coated with a reflective material and is equipped with a GPS positioning module for real-time tracking of the position of the helium balloon.

[0029] As a further scheme of the present application: the folding structure of the alarm device is made of carbon fiber material, which is light in weight and high in strength, facilitating quick deployment and storage.

[0030] As a further scheme of the present application: the data processing unit is equipped with a self-learning function, which can optimize the prediction accuracy of the LSTM neural network based on historical data.

[0031] As a further scheme of the present application: the data transmission unit supports multi-channel redundant transmission, ensuring data transmission even when a communication channel fails.

[0032] As a further scheme of the present application: the power management module is equipped with an intelligent charging and discharging control algorithm for optimizing the charging and discharging efficiency of the solar panel and the backup battery, and the charging and discharging control algorithm is:

[0033] Pcharge = η · Psolar - Pload

[0034] Where Pcharge is the charging power, η is the charging efficiency, Psolar is the output power of the solar panel, and Pload is the system load power.

[0035] As a further scheme of the present application: the system is equipped with a self-checking function, which can periodically detect the working state of the sensors, cameras and alarm devices, and issue an alarm when a fault is found, specifically including:

[0036] 1) Sensor self-checking: periodically check the working state of the vibration sensor and displacement sensor to ensure the accuracy of data acquisition.

[0037] 2) Camera self-checking: check the focusing, anti-shake and night vision functions of the camera to ensure the clarity of image data.

[0038] 3) Alarm device self-checking: check the working state of the helium balloon inflator and the light warning sign to ensure the reliability of the alarm function.

[0039] As a further scheme of the present application: the system is also equipped with a mobile terminal interface, and users can view monitoring data and alarm information in real time through mobile phones or tablets, and support remote control of the layout and inflation of the alarm device; specifically including:

[0040] 1) Real-time data viewing: Users can view real-time data from vibration sensors, displacement sensors, and cameras through mobile terminals.

[0041] 2) Remote control: Users can remotely control the deployment, inflation, and ascent of the alarm device, improving the flexibility of emergency response.

[0042] Compared with the prior art, the beneficial effects of the present application are:

[0043] 1) In the present application, vibration sensors and displacement sensors are combined to provide comprehensive monitoring data, and cameras provide real-time images to enhance monitoring effectiveness. The networked alarm device and helium balloon design allow for rapid transmission of alarm information.

[0044] 2) The folding structure design of the present application facilitates portability and deployment, making it suitable for emergency use. The use of solar panels and backup batteries ensures continuous system operation. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0046] In the embodiments of the present application, a geological disaster monitoring system includes a sensor module, a slope protection structure monitoring module, an alarm device, a data processing and transmission module, and a power management module. The sensor module is used for real-time monitoring of geological disasters. The slope protection structure monitoring module is used for synchronous monitoring of the stability of the slope protection structure. The alarm device is used for rapid warning in the event of a geological disaster. The data processing and transmission module is used for real-time analysis and transmission of monitoring data. The power management module is used to provide continuous power supply for the system. The sensor module includes vibration sensors, displacement sensors, and a data fusion algorithm module. The slope protection structure monitoring module includes vibration sensors and displacement sensors matched with the slope protection structure, a high-definition camera, and an image processing module. The alarm device includes a networked alarm device and a helium balloon that can be quickly inflated. The data processing and transmission module includes a data processing unit and a data transmission unit. The power management module includes solar panels and backup batteries.

[0047] The vibration sensor in the sensor module is used to detect the ground vibration of the monitoring area, and the sensitivity thereof can be adjusted, and the detection frequency range is 0.1 Hz to 100 Hz; the displacement sensor is used to measure the ground displacement change of the monitoring area, and the measurement accuracy is ±0.1 mm, and the maximum range is ±500 mm; the vibration sensor and the displacement sensor process the monitoring data through a data fusion algorithm, and the data fusion algorithm is:

[0048] Df = a * Dv + (1-a) * Dd

[0049] Wherein, Df is the fused data, Dv is the vibration sensor data, Dd is the displacement sensor data, and a is the weight coefficient, and the value range is 0.5 to 0.8;

[0050] After the above technical scheme is adopted, the vibration sensor and the displacement sensor are combined to provide comprehensive monitoring data.

[0051] The vibration sensor and the displacement sensor in the slope protection structure monitoring module are used to monitor the vibration and displacement of the slope protection structure; the high-definition camera is equipped with a wide-angle lens and a night vision function, and is used to acquire image data of the monitoring area in real time; the image processing unit is used to analyze the image collected by the camera in real time, and an edge detection algorithm is used to identify the cracks and deformation of the slope protection structure, and the edge detection algorithm is:

[0052]

[0053] Wherein, E(x,y) is the edge intensity, Gx and Gy are the gradient operators in the horizontal and vertical directions respectively, and I(x,y) is the image pixel value;

[0054] The networking alarm device in the alarm device is connected with the traffic warning light and other alarm devices, adopts LoRa or NB-IoT communication protocol, and is used for rapid transmission of alarm information; the helium balloon in the rapidly inflatable helium balloon is hung under the light warning sign, adopts high-brightness LED light source, and the surface of the warning sign is coated with reflective material, and is used for airborne warning; the alarm device is of a folding structure, is made of light weight and high strength material, and is convenient for carrying and laying;

[0055] The data processing unit in the data processing and transmission unit is equipped with an artificial intelligence algorithm, which is used for deep analysis of the data of the vibration sensor and the displacement sensor, and the artificial intelligence algorithm is an LSTM neural network model based on time series, and the prediction formula is:

[0056] h t = σ (W h · [h t -1, hx t ] + b h )

[0057] where h t is the hidden state at the current time, W h is the weight matrix, b h is the bias term, σ is the activation function, x t is the input data at the current time.

[0058] The data transmission unit supports 4G, 5G and satellite communication, for real-time transmission of monitoring data and alarm information to the monitoring center.

[0059] The solar panels in the power management module are equipped with a maximum power point tracking (MPPT) algorithm for daytime power supply to the system. The MPPT algorithm is:

[0060] P max = V mp ·I mp

[0061] where P max is the maximum power, V mp and I mp are the voltage and current corresponding to the maximum power point, respectively.

[0062] The backup battery uses lithium-ion batteries and is equipped with a power monitoring function, which can display the remaining power in real time and issue a warning when the power is insufficient.

[0063] The data acquisition frequency of the vibration sensor and displacement sensor can be adjusted to adapt to different geological monitoring needs, with a data acquisition frequency range of 1Hz to 100Hz.

[0064] The high-definition camera is equipped with automatic focusing and anti-shake functions, and can obtain clear monitoring images in adverse weather conditions.

[0065] The helium balloon of the alarm device is coated with a reflective material and is equipped with a GPS positioning module to track the location of the helium balloon in real time.

[0066] The folding structure of the alarm device is made of carbon fiber material, which is light in weight and high in strength, facilitating quick deployment and storage.

[0067] The data processing unit is equipped with a self-learning function, which can optimize the prediction accuracy of the LSTM neural network based on historical data.

[0068] The data transmission unit supports multi-channel redundant transmission to ensure data transmission even when one communication channel fails.

[0069] The power management module is equipped with an intelligent charging and discharging control algorithm to optimize the charging and discharging efficiency of the solar panel and the backup battery. The charging and discharging control algorithm is:

[0070] Pcharge = η · Psolar - Pload

[0071] Where Pcharge is the charging power, η is the charging efficiency, Psolar is the solar panel output power, and Pload is the system load power.

[0072] The system is equipped with a self-checking function that can periodically detect the working status of sensors, cameras, and alarm devices and issue an alarm when a fault is found. Specifically, it includes:

[0073] 1) Sensor self-checking: Regularly check the working status of vibration sensors and displacement sensors to ensure the accuracy of data collection.

[0074] 2) Camera self-checking: Check the focusing, anti-shake, and night vision functions of the camera to ensure the clarity of image data.

[0075] 3) Alarm device self-checking: Check the working status of the helium balloon inflator and the light-emitting warning sign to ensure the reliability of the alarm function.

[0076] The system also has a mobile terminal interface, allowing users to view monitoring data and alarm information in real time through their mobile phones or tablets and support remote control of the layout and inflation of the alarm device. Specifically, it includes:

[0077] 1) Real-time data viewing: Users can view real-time data from vibration sensors, displacement sensors, and cameras through their mobile terminals.

[0078] 2) Remote control: Users can remotely control the layout, inflation, and ascent of the alarm device to improve the flexibility of emergency response.

[0079] Example 1

[0080] 1) Sensor layout:

[0081] Vibration sensors and displacement sensors are placed in key locations in the monitoring area, such as slopes, retaining structures, and areas along the traffic line where geological disasters are prone to occur. The installation location of the sensors needs to be determined through geological survey to ensure that it can cover potential disaster areas. The data collection frequency of the sensors is set to 1Hz to 100Hz according to actual needs and can be adjusted remotely.

[0082] Data collection and fusion:

[0083] Vibration sensors collect real-time ground vibration data, and displacement sensors collect real-time ground displacement data.

[0084] The data fusion algorithm is implemented by the following formula:

[0085] Df = a · Dv + (1 - a) · Dd

[0086] Wherein, a is dynamically adjusted according to the geological conditions, the value range is 0.5 to 0.8.

[0087] The fused data is sent to the data processing unit through the data transmission module.

[0088] 2) Implementation of slope protection structure monitoring module

[0089] Camera layout:

[0090] High-definition camera is installed near the slope protection structure to ensure that it can cover the overall area of the slope protection structure. The camera is equipped with a wide-angle lens and night vision function, which can obtain clear image data at night or in insufficient light.

[0091] Image processing and analysis: The image processing unit analyzes the video collected by the camera in real time, and uses edge detection algorithm to identify the cracks and deformation of the slope protection structure. The formula of edge detection algorithm is:

[0092]

[0093] Wherein, E(x,y) is the edge strength, Gx and Gy are the gradient operators in horizontal and vertical directions respectively, and I(x,y) is the image pixel value.

[0094] The detected crack and deformation data are sent to the data processing unit through the data transmission module.

[0095] 3) Implementation of alarm device

[0096] Alarm device layout:

[0097] The alarm device is laid in the traffic artery, densely populated area or disaster-prone area. The folding structure of the alarm device is made of carbon fiber material, which is light in weight and high in strength, convenient to carry and lay out.

[0098] Helium balloon and light-emitting warning sign:

[0099] The helium balloon can be quickly inflated and ascended, and the high-brightness LED light-emitting warning sign is hung down. The surface is coated with reflective material, which can provide warning at a long distance. The helium balloon is equipped with a GPS positioning module for real-time tracking of the position of the helium balloon.

[0100] Alarm information transmission:

[0101] The alarm device is connected with traffic warning lights and other alarm devices, using LoRa or NB-IoT communication protocol to ensure the rapid transmission of alarm information. The alarm information is sent to the monitoring center and the user's mobile terminal through the data transmission module.

[0102] 4) Implementation of data processing and transmission module

[0103] The data processing unit is equipped with a LSTM neural network model based on time series for deep analysis of vibration sensor and displacement sensor data. The prediction formula of LSTM neural network is:

[0104] h t =σ(W h ·[h t -1,hx t ]+b h )

[0105] Where h t is the hidden state at the current time, W h is the weight matrix, b h is the bias term, σ is the activation function, and x t is the input data at the current time.

[0106] The data processing unit optimizes the prediction accuracy of the LSTM neural network based on historical data and generates a geological disaster warning report.

[0107] The data transmission unit supports 4G, 5G and satellite communication, using multi-channel redundant transmission technology to ensure data transmission even if one communication channel fails. The monitoring data and alarm information are transmitted in real time to the monitoring center and the user's mobile terminal through the data transmission module.

[0108] 5) Implementation of power management module

[0110] Solar panels are installed in sunny locations in the monitoring area and equipped with a maximum power point tracking (MPPT) algorithm to provide power to the system during the day. The formula for the MPPT algorithm is:

[0111] P max =V mp ·I mp

[0112] Where P max is the maximum power, V mp and I mp are the voltage and current corresponding to the maximum power point, respectively.

[0113] The backup battery uses lithium-ion batteries and is equipped with a power monitoring function that can display the remaining power in real time and issue a warning when the power is low.

[0114] The intelligent charging and discharging control algorithm is used to optimize the charging and discharging efficiency of the solar panel and the backup battery, and the formula is:

[0115] Pcharge = η · Psolar - Pload

[0116] Wherein: Pcharge is the charging power, η is the charging efficiency, Psolar is the solar panel output power, and Pload is the system load power.

[0117] 6) Implementation of system self-check and maintenance

[0118] Sensor self-check:

[0119] The system regularly checks the working state of the vibration sensor and the displacement sensor to ensure the accuracy of data acquisition. The self-check result is sent to the monitoring center through the data transmission module.

[0120] Camera self-check:

[0121] The system regularly checks the focusing, anti-shake and night vision functions of the camera to ensure the clarity of image data. The self-check result is sent to the monitoring center through the data transmission module.

[0122] Alarm device self-check:

[0123] The system regularly checks the working state of the helium balloon inflator and the light warning sign to ensure the reliability of the alarm function. The self-check result is sent to the monitoring center through the data transmission module.

[0124] 7) Implementation of user interaction and remote control

[0125] Real-time data viewing: Users can view real-time data of vibration sensors, displacement sensors and cameras through mobile phones or tablets in real time. Data is displayed in the form of charts and images, making it easy for users to intuitively understand the situation of the monitoring area.

[0126] Remote control: Users can remotely control the layout, inflation and lifting of the alarm device to improve the flexibility of emergency response. Remote control instructions are sent to the alarm device through the data transmission module.

[0127] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A geological disaster monitoring system comprising a sensor module, a slope protection structure monitoring module, an alarm device, a data processing and transmission module and a power management module, characterized in that: The sensor module includes a vibration sensor, a displacement sensor, and a data fusion algorithm module, the slope structure monitoring module includes vibration sensors and displacement sensors matched with the slope structure, a high-definition camera, and an image processing module, the alarm device includes a networked alarm device and a quickly inflatable helium balloon, the data processing and transmission module includes a data processing unit and a data transmission unit, and the power management module includes a solar panel and a backup battery. The detection frequency range of the vibration sensor in the sensor module is 0.1 Hz to 100 Hz; the displacement sensor is used to measure the ground displacement change of the monitoring area, the measurement accuracy is ±0.1 mm, and the maximum range is ±500 mm; the vibration sensor and the displacement sensor process the monitoring data through a data fusion algorithm, and the data fusion algorithm is: Df=α·Dv+(1-α)·Dd wherein Df is the fused data, Dv is the vibration sensor data, Dd is the displacement sensor data, and a is a weight coefficient, and the value range is 0.5 to 0.8; The vibration sensor and the displacement sensor in the slope structure monitoring module, the high-definition camera is equipped with a wide-angle lens and a night vision function, an image processing unit is used to analyze the images collected by the camera in real time, an edge detection algorithm is used to identify the cracks and deformation of the slope structure, and the edge detection algorithm is: wherein E(x,y) is the edge intensity, Gx and Gy are the gradient operators in the horizontal and vertical directions respectively, and I(x,y) is the image pixel value; The networked alarm device in the alarm device is connected with a traffic warning light and other alarm devices; the helium balloon in the quickly inflatable helium balloon is hung with a light-emitting warning sign, and the alarm device is a folding structure; The data processing unit in the data processing and transmission unit is equipped with an artificial intelligence algorithm for deep analysis of the data of the vibration sensor and the displacement sensor, and the artificial intelligence algorithm is an LSTM neural network model based on time series, and the prediction formula is: h t = σ(W h · [h t -1,hx t + b h ) where h t is the hidden state at the current time, W h is the weight matrix, b h is the bias term, σ is the activation function, and x t is the input data at the current time. The data transmission unit supports 4G, 5G and satellite communication, the solar panel in the power management module is equipped with a maximum power point tracking algorithm for power supply during the day, and the MPPT algorithm is: P max = V mp · I mp where Pmax is the maximum power, Vmax and Imax are the voltage and current at the maximum power point, respectively. max mp mp where Pmax is the maximum power, Vmax and Imax are the voltage and current at the maximum power point, respectively.​​ The backup battery adopts a lithium ion battery and is equipped with a power monitoring function, which can display the remaining power in real time and issue a warning when the power is insufficient.

2. The geological disaster monitoring system according to claim 1, characterized in that: The data acquisition frequency of the vibration sensor and the displacement sensor is adjustable, and the data acquisition frequency range is 1 Hz to 100 Hz.

3. The geological disaster monitoring system according to claim 1, wherein: The high-definition camera is equipped with an automatic focusing and anti-shake function.

4. The geological disaster monitoring system according to claim 1, wherein: The surface of the helium balloon of the alarm device is coated with a reflective material and is equipped with a GPS positioning module.

5. The geological disaster monitoring system according to claim 1, wherein: The folding structure of the alarm device is made of carbon fiber material.

6. The geological disaster monitoring system according to claim 1, wherein: The data processing unit is equipped with a self-learning function.

7. The geological disaster monitoring system according to claim 1, wherein: The data transmission unit supports multi-channel redundant transmission.

8. The geological disaster monitoring system according to claim 1, wherein: The power management module is equipped with an intelligent charging and discharging control algorithm, and the charging and discharging control algorithm is: Pcharge=η·Psolar-Pload Wherein, Pcharge is the charging power, η is the charging efficiency, Psolar is the solar panel output power, Pload is the system load power.

9. The geological disaster monitoring system according to claim 1, wherein: The system is equipped with self-checking function, which can regularly detect the working state of sensors, cameras and alarm devices, and issue an alarm when a fault is found.

10. The geological disaster monitoring system according to claim 1, wherein: The system is also equipped with a mobile terminal interface, allowing users to view monitoring data and alarm information in real time through a mobile phone or tablet computer, and supporting remote control of alarm device deployment and inflation.

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