JP2005186639A - Seating sensing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seating sensing device capable of determining the seated object with high reliability and simplifying the constitution in terms of hardware and software. <P>SOLUTION: The seating sensing device has a pressure sensor 20 installed on the seating surface 1 of each seat and composed of a front pressure sensor unit 20A including a plurality of pressure sensing cells 10 arranged in the front region of the seating surface and a rear pressure sensor unit 20B including a plurality of pressure sensing cells arranged in the rear region of the seating surface, wherein further a determining part is installed to determine the seated object on the seat on the basis of the correlation between the front signal value FS given by the front sensor unit and the rear signal value RS given by the rear sensor unit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a seating device comprising: a pressure-sensitive sensor comprising a plurality of pressure-sensitive cells disposed on a seating surface of a seat; and a determination unit that determines a seating object on the seat based on a signal from the pressure-sensitive sensor. The present invention relates to a detection device. The determination of the sitting object described here means determination of whether a child seat is placed on the seat, whether a child is seated, or an adult is seated.

  As a conventional technique, an occupant detection sensor used as a seating detection sensor is disposed in the vicinity of the front end portion of the seat cushion along the seat width direction, and is disposed along the seat width direction at a substantially central portion in the front-rear direction of the seat cushion. Each switch unit is divided into groups according to the load to be turned on in order to configure the switch unit and use it for weight discrimination, etc., and for each group, the switch unit is grouped and connected to the connector by an extension line. Three types of switch units are set to be turned on according to weight (example 15 kg), adult light weight (example 30 kg), and heavy weight (example 45 kg), and the airbags are activated by the on / off signals of each grouped switch unit. A configuration is known in which the controller varies the gas output to the airbag bag body (see Patent Document 1). However, in such a configuration, since the sitting object is determined only by the behavior of the switch unit that is turned on or off according to weight, there is a problem that the determination accuracy is not sufficient.

  Eight sensors (pressure-sensitive cells in this application) are arranged for every six columns on the left and right sides that are symmetrical with respect to the center line extending in the front-rear direction at the center of the seating surface. 6cm, 9cm, and 12cm away from each other, and corresponding to the average center of gravity of 30kg, 60kg and 90kg people, the signals of the sensor group grouped in each row A seating detection device for evaluating body weight is known (see Patent Document 2). However, in this device, the distance between the sensor group rows grouped by weight is only 3 cm, so even if the seating position is deviated by 1 cm in the horizontal direction, the signal from each sensor group row fluctuates to change the seating object. There is a problem that it is difficult to make a determination with satisfactory reliability.

  Furthermore, a seating detection device has also been proposed in which pressure-sensitive cells are arranged in a matrix on a seating surface and a seating object is determined by template matching of a pressure distribution obtained from pressure signals from each pressure-sensitive cell (see Patent Document 3). .) With this seating detection device, the number of wires and connectors required to individually read the pressure signals of all the pressure sensitive cells increases, which increases the hardware cost and the program cost for executing template matching. However, there is a problem that the overall cost is high.

JP-A-10-39045 (paragraph numbers 0010 and 0035, FIG. 8)

German Patent Application Publication No. 10143326 A1 (paragraph numbers 0026-0028, FIG. 1)

JP 2001-180354 A (paragraph numbers 0018, 0026, 0032)

  The present invention is for solving the above-described problems, and the problem is that a seating detection apparatus that can determine a seating object with sufficient reliability and is simplified in terms of hardware and software. Is to provide

  The technical means taken in order to achieve the above-mentioned objects are: a pressure-sensitive sensor comprising a plurality of pressure-sensitive cells disposed on the seating surface of the seat; and a seating object on the seat based on a signal from the pressure-sensitive sensor In the seating detection apparatus comprising the determination unit for determining the front pressure sensor unit, the pressure sensor includes a front pressure sensor unit including a plurality of pressure sensing cells disposed in a front region of the seating surface, and a rear region of the seating surface. A rear pressure sensor unit including a plurality of arranged pressure sensitive cells, and the determination unit correlates a front signal value from the front pressure sensor unit and a rear signal value from the rear pressure sensor unit. The seating object in the seat is determined based on the relationship.

  According to the first technical means, a plurality of pressure-sensitive cells arranged on the seating surface of the seat are grouped by those arranged in the front region and the rear region of the seating surface, and each of them is front pressure-sensitive. As the sensor unit and the rear pressure sensor unit, only two systems of output signals are used, and determination of the object sitting on the seat from the correlation between the values of the two output signals, that is, the front signal value and the rear signal value, for example, the seat A determination is made as to whether a child seat is placed, whether a child is seated, or an adult is seated. Since only two signals are extracted, and the object sitting on the seat is determined by evaluating the correlation between the two signal values, the configuration is simple both in terms of hardware and software. Leads to cost reduction. In addition, although the configuration is simple, the difference in pressure distribution when an adult or child as a seated object is seated on a seat or a child seat is installed is significant in the front and rear regions of the seat. Since the correlation of the signal values from the region is evaluated, the determination finally obtained has satisfactory reliability.

  In order to further improve the accuracy of determination between adults and children (or child seats) sitting on a seat, it is effective to increase the difference in signal values output in each case. As one proposal for this, a pressure-sensitive cell constituting the front pressure-sensitive sensor unit and a pressure-sensitive cell constituting the rear pressure-sensitive sensor unit are arranged in the central region of the seating surface so as to be electrically connected. There is a seating detection device configured as described above. This means that even if the child sits in various ways with respect to the central area of the seating surface, both adults and children (or child seats) will apply a certain amount of load, but adults will have children (or child seats). If you think that you have a much larger body weight than the front, the values of the front signal value and rear signal value that are output when the adult is seated, and when the child is seated or when the child seat is installed This is because the difference between the front signal value and the rear signal value increases.

  As another proposal that provides the same effect, there is a seating detection device in which a pressure-sensitive cell, which is subjected to a greater load when an adult is seated, has a higher pressure-sensitive output performance than other pressure-sensitive cells. In other words, since the seating surface area to which a large load is applied by the seated adult can be specified to some extent, the pressure-sensitive cell to be disposed in this specified area is compared with other pressure-sensitive cells per unit pressure. The front signal value and the rear signal value that are output when an adult is seated and the front signal that is output when a child is seated or a child seat is installed. The difference between the value and each of the rear signal values is increased to improve the determination accuracy.

  If the above proposal is approached from the opposite direction, a pressure-sensitive cell that requires a larger load when a child is seated or a child seat is installed has a lower pressure-sensitive output performance than other pressure-sensitive cells. A seating detection device can also be proposed as improving the determination accuracy.

Furthermore, based on the knowledge that the position of the center of gravity (generally near the front center) of the seating surface when a child is seated or when a child seat is installed is generally different from that of an adult, the child seat or child seat is installed. The seating detection device that originally omitted the placement of the pressure-sensitive cell in the child's center of gravity area on the seating surface is also the front signal value and rear signal value that are output when an adult is seated. The difference between the front signal value and the rear signal value output when the child is seated or when the child seat is installed can be increased, which is convenient for improving the determination accuracy. The center-of-gravity region is a region that cannot be the center of gravity when an adult is seated on a seat and can only be the center of gravity when a child is seated on a seat or seated through a child seat. For example, the center of gravity region can include the vicinity of the front center of the seating surface of the seat.
Other features and advantages of the present invention will become apparent from the following description of embodiments using the drawings.

  First, the characteristic principle of the seating detection apparatus according to the present invention will be described with reference to FIGS. As shown in FIG. 1, a pressure-sensitive sensor is configured by a plurality of pressure-sensitive cells 10 that are distributed on the seating surface 1 of the seat and respond to load loads such as a human body seated on the seat. A plurality of pressure-sensitive cells 10 disposed in the front area of the seating surface 1 are grouped to form one front pressure-sensitive sensor unit 20A, and a plurality of pressure-sensitive cells disposed in the rear area of the seating surface 1 are formed. The pressure cells 10 are grouped to form one rear pressure sensor unit 20B, and signals from the front pressure sensor unit 20A and the rear pressure sensor unit 20B are respectively transmitted to the front signal via the measurement electronic system 40. The value FS and the rear signal value RS are input to the evaluation electronic system 50 that functions as a determination unit that performs the sitting object determination.

  The front pressure sensor unit 20A and the rear pressure sensor unit 20B have a central region 20C that overlaps at the center. In the central region 20C, the pressure sensitive cell 10 constituting the front pressure sensor unit 20A and the pressure sensitive cell 10 constituting the rear pressure sensor unit 20B are electrically connected. At that time, the connection of the pressure sensitive cells 10 is not limited to one line, and the connection of the pressure sensitive cells 10 may exist in a plurality of lines. In the measurement electronic system 40, switching between the front signal value FS and the rear signal value RS can be performed.

  The signals from the front pressure sensor unit 20A and the rear pressure sensor unit 20B correspond to the total output value of each pressure sensor cell 10 included therein, and when a child is seated, a child seat is installed. In this case, various combinations of the front signal value FS and the rear signal value RS can be obtained when an adult is seated and the difference in seating position in each case. For example, the distribution of evaluation points determined from the front signal value FS and the rear signal value RS each time several children (or child seats) and adults are seated on the seating surface 1 in various postures as a sample. This is shown in FIG. In the graph of FIG. 2, the horizontal axis represents the front signal value FS, and the vertical axis represents the rear signal value RS. The evaluation points in the sample where the child is seated or the child seat is installed are indicated by X, P1 to Pn symbols are added, the evaluation points in the sample where the adult is seated are indicated by ○, Q1 to Qn The code | symbol of is attached. The child / child seat region Gp {P1... Pn} in which the evaluation points of the sample where the child is seated or the child seat is installed is distributed is a region where both the front signal value FS and the rear signal value RS are small values. It can be understood that the adult region Gq {Q1... Qn} in which the evaluation points of samples on which adults are seated is a region where both the front signal value FS and the rear signal value RS are large values. There is a clear boundary region between the child / child seat region Gp {P1... Pn} and the adult region Gq {Q1... Qn}, and a boundary line extending along the center of the boundary region is shown. When defined as a threshold function T (the function here is not defined with mathematical rigor, but should be understood as an expression defining a specific boundary or boundary region), this threshold By using the function T to determine the evaluation point determined by the front signal value FS and the rear signal value RS, it is possible to determine whether the seated object is an adult, a child, or a child seat. That is, the graph of FIG. 2 shows that the sitting object determination can be performed based on the correlation between the front signal value FS and the rear signal value RS. The threshold function T may be a straight line, but a curved line or a step-like line may be adopted to more accurately follow the boundary line. When the threshold function T is actually used in the evaluation electronic system 50, it is common to take a form like a tabulated threshold set.

  When the seated object is determined from the front signal value FS and the rear signal value RS input using such a threshold function T, as is apparent from FIG. 2, the child / child seat region Gp {P1... Pn} It is convenient to configure the front pressure sensor unit 20A and the rear pressure sensor unit 20B so that the distance between the adult regions Gq {Q1... Qn} is increased. A preferred embodiment for this purpose will be described later. For example, when the pressure sensitive cell 10 that is more heavily loaded when an adult is seated is configured to output at a higher level than other pressure sensitive cells 10, FIG. In the graph shown in FIG. 3, the adult region Gq {Q1... Qn} is further away from the child / child seat region Gp {P1... Pn} like the graph shown in FIG. By using the function T, the sitting object can be determined with sufficient reliability even if the posture or the like of the sitting object to be determined changes. Also, for the same purpose, conversely, when a child is seated or when a child seat is installed, a pressure sensitive cell that is more heavily loaded is configured to output at a lower level than other pressure sensitive cells, or When a measure is adopted as if the pressure sensitive cell 10 in the center of gravity area of the child or child seat on the seating surface 1 when the child is seated or when the child seat is installed is adopted, the graph shown in FIG. As shown in the graph, the child / child seat region Gp {P1... Pn} moves further away from the adult region Gq {Q1... Qn} toward the origin, and the threshold function T defined by the boundary line is used. Thus, even if the posture or the like of the sitting object to be determined changes, the sitting object can be determined with sufficient reliability.

  Next, a specific embodiment in which the seating detection device according to the present invention is applied to a seat of an automobile will be described. FIG. 5 is a perspective view of a passenger seat of an automobile, and a seat 100 is composed of a seat skin 101, a seat cushion 102, a cushion support spring 103, and the like that form the seating surface 1 in order from the top. A sheet 104 is attached. The pressure-sensitive sensor 20 includes a front pressure-sensitive sensor unit 20 </ b> A including a plurality of pressure-sensitive cells 10 disposed in the front region of the seating surface 1 and a plurality of pressure-sensitive cells 10 disposed in the rear region of the seating surface 1. The rear pressure sensor unit 20B is included.

  As shown in FIG. 6, the pressure-sensitive sensor 20 includes a plurality of pressure-sensitive cells 10 configured in parallel with a pressure-sensitive resistor Rs whose resistance value changes according to pressure and a fixed resistor Rc. Thus, the measurement electronic system 40 is connected. The front pressure sensor unit 20 </ b> A is configured by connecting pressure-sensitive cells 10 disposed in the front region of the seat 100 in series, and the rear pressure sensor unit 20 </ b> B is disposed in the rear region of the seat 100. The pressure sensitive cell 10 is configured by connecting the pressure sensitive cells 10 in series. In the central region 20C of the seat 100, the pressure sensitive cell 10 included in the front pressure sensitive sensor unit 20A and the pressure sensitive cell included in the rear pressure sensitive sensor unit 20B. 10 are mixed. The total resistance value of the resistance values of the pressure-sensitive cells 10 connected in series included in each of the front pressure sensor unit 20A and the rear pressure sensor unit 20B configured in this manner is the load applied to the seating surface 1. Corresponding output values are obtained by the measurement electronic system 40 and the respective output values are sent to the evaluation electronic system 50 as a front signal value FS and a rear signal value RS.

  In the central region 20C, the pressure sensitive cell 10 constituting the front pressure sensor unit 20A and the pressure sensitive cell 10 constituting the rear pressure sensor unit 20B are electrically connected. At that time, the connection of the pressure sensitive cells 10 is not limited to one line, and the connection of the pressure sensitive cells 10 may exist in a plurality of lines. In the measurement electronic system 40, switching between the front signal value FS and the rear signal value RS can be performed.

  The reason why the pressure sensitive cells 10 included in the front pressure sensor unit 20A and the pressure sensitive cells 10 included in the rear pressure sensor unit 20B are mixed in the central region 20C of the seat 100 is that the object being seated is a child. Alternatively, the pressure-sensitive cells 10 of both pressure-sensitive sensor units 20A and 20B are disposed in the central region 20C of the seat 100 that is likely to receive a main load in common, whether it is a child seat or an adult. This is to increase the difference between the total amount of the front signal value FS and the rear signal value RS when the child is seated or when the child seat is installed and when the adult is seated. In other words, by increasing the weight of the central region 20C of the seat 100 when obtaining the front signal value FS and the rear signal value RS for both of the pressure sensor units 20A and 20B, in the case of a light weight child or child seat It is devised so that a smaller signal value is output in the case of an adult with a heavy weight.

  The specific structure of each pressure-sensitive cell 10 is shown in FIG. 7, and two flexible insulations laid in a state where they are face-to-face with a small gap between the seat skin 101 and the seat cushion 102. On one inner surface of the films 11a and 11b, a pair of comb-like electrodes 12a as a pair of opposed electrodes on a plane with a distance between the electrodes in the film surface direction corresponding to the position of each pressure sensitive cell 10 in plan view, 12b is formed, and the resistance layer 13 constituting the fixed resistor Rc is connected to the electrodes of the pair of comb-like electrodes 12a and 12b at the lateral side position of the region where the comb-like electrodes 12a and 12b are formed. On the other inner surface of the two insulating films 11a and 11b, the pressure-sensitive resistance layer 14 constituting the pressure-sensitive resistance Rs is formed opposite to the formation region of the pair of comb-like electrodes 12a and 12b. Yes. In the figure, reference numeral 15 denotes a resin layer serving as a spacer for setting a gap between two insulating films 11a and 11b and a joining member for joining the two films 11a and 11b. A known resistance ink having a predetermined resistance is used for the resistance layer 13, and a known pressure-sensitive ink whose resistance value is reduced when pressure is applied is used for the pressure-sensitive resistance layer 14.

  As described above, depending on whether the evaluation point determined by the front signal value FS and the rear signal value RS is located in the child / child seat area or the adult area defined by the threshold (boundary) function T (that is, the front signal) The seating object determination is performed in the evaluation electronic system 50 (based on the correlation between the value FS and the rear signal value RS). This threshold function T is tabulated and stored in a threshold LUT (lookup table) 51. . The threshold value LUT (lookup table) 51 stores not only one threshold function T but also a plurality of different threshold functions T such as linear, multi-order, or stepped shape, and the seat seat 100 or the pressure sensor. It may be configured to select and use an optimal one from the characteristics of 20 habits or a person who frequently sits in the passenger seat. In any case, the determination information output from the evaluation electronic system 50 is transmitted to the airbag control electronic system 60 and used for controlling the passenger seat airbag 70.

  As a measure to output a smaller signal value in the case of a lighter child or child seat and a larger signal value than in a heavy weight adult, in a region where a relatively large load is applied when an adult is seated. It is also possible to configure the pressure-sensitive cell 10 to be disposed using, for example, pressure-sensitive ink having a larger amount of variation in resistance value with respect to pressure. Conversely, when a child is seated or when a child seat is installed, a relatively large load is generated, whereas when an adult is seated, a relatively small load is generated. It is also possible to configure the pressure-sensitive cell 10 disposed in the pressure-sensitive cell 10 using, for example, pressure-sensitive ink that has a smaller amount of variation in resistance value with respect to pressure. Extremely, a measure not to arrange the pressure sensitive cell 10 in the front center region of the seat 100 is also effective.

  The threshold function T incorporated in the evaluation electronic system 50 is derived from a number of samples of the front signal value FS and the rear signal value RS acquired by seating a child (including a child seat) or an adult on the seat seat 100 experimentally. A graph as shown in FIG. 2 to FIG. 4 is created, and a boundary line between the child / child seat region Gp {P1... Pn} and the adult region Gq {Q1. Therefore, it is tabulated as a threshold value for each unit amount of the front signal value FS or the rear signal value RS and stored in the threshold value LUT 51. The relationship between the threshold function T and the child / child seat area and adult area partitioned by the threshold function T is schematically shown in FIG. Both the front signal value FS and the rear signal value RS corresponding to the total resistance value (corresponding to a load) of the pressure sensitive cell 10 included in each of the front pressure sensor unit 20A and the rear pressure sensor unit 20B are within a predetermined range. A region having a small value is a region that is determined to be a child or a child seat, and a region having a large value in both the front signal value FS and the rear signal value RS is a region that is determined to be an adult. Thereby, it is possible to immediately determine whether the evaluation point determined from the front signal value FS and the rear signal value RS caused by the seated object belongs to the child / child seat region or the adult region. Or a child seat) or an adult, and the reliability is statistically supported.

  In the above embodiment, the pressure sensitive cell 10 is configured to change the resistance value by a load, and the measurement electronic system 40 is configured to obtain the total resistance value of the pressure sensitive cells 10 connected in series. Instead, as shown in FIG. 9, the pressure sensitive cell 10 is configured by a parallel connection of a pressure sensitive switch Rsw and a fixed resistance Rcw that can be switched between a high resistance state and a low resistance state by pressure (load load). A plurality of pressure sensitive cells 10 may be connected in series to form a front pressure sensor unit 20A and a rear pressure sensor unit 20B. Here, the front pressure sensor unit 20A and the rear pressure sensor unit 20B have a central region 20C that overlaps at the center. In the central region 20C, the pressure sensitive cell 10 constituting the front pressure sensor unit 20A and the pressure sensitive cell 10 constituting the rear pressure sensor unit 20B are electrically connected. At that time, the connection of the pressure sensitive cells 10 is not limited to one line, and the connection of the pressure sensitive cells 10 may exist in a plurality of lines. In the measurement electronic system 40, switching between the front signal value FS and the rear signal value RS can be performed. At that time, the measurement electronic system 40 obtains the number of operation of the pressure sensitive switch Rsw from the total resistance value of the plurality of pressure sensitive cells 10 connected in series of the front pressure sensor unit 20A and the rear pressure sensor unit 20B. The number of operations is output to the evaluation electronic system 50 as a front signal value FS and a rear signal value. The relationship between the threshold function T as a criterion stored in the threshold LUT 51 of the evaluation electronic system 50, the front signal value FS, and the rear signal value is schematically shown in FIG. Here, both the front signal value FS and the rear signal value RS corresponding to the number of pressure-sensitive switch operations of the pressure-sensitive cell 10 included in each of the front pressure sensor unit 20A and the rear pressure sensor unit 20B are small values within a predetermined range. The area having the symbol is an area where the child seat or the child seat is determined, and the area where both the front signal value FS and the rear signal value RS have a large value within a predetermined range is an area determined as an adult.

  In the above description regarding the arrangement configuration of the pressure sensitive cells 10 in the central region 20C of the seating surface 1, the pressure sensitive cells 10 included in the front pressure sensor unit 20A and the pressure sensitive sensors included in the rear pressure sensor unit 20B are included in the central region 20C. Although both of the cells 10 are arranged, as can be understood from FIG. 1 and the like, it is also convenient to make the arrangement distribution density of both the pressure sensitive cells 10 in the central region 20C denser than that of the front region and the rear region. It is. Of course, the arrangement distribution density of the pressure sensitive cells 10 may be the same in all regions. In any case, the pressure sensitive cell 10 disposed in the central region 20C is connected to both the front pressure sensor unit 20A and the rear pressure sensor unit 20B, and the front pressure sensor unit 20A and the rear pressure sensor unit 20B. The pressure-sensitive measurements are switched to each other, and only the pressure-sensitive cell 10 disposed in the central region 20C contributes to the measurement outputs of both the front pressure sensor unit 20A and the rear pressure sensor unit 20B. May be.

  In the above embodiment, the seating detection device according to the present invention is applied to the seat of an automobile. However, the seating detection device can be applied to detection of seating states in other various seats.

Schematic explaining the principle of the seating detection device according to the present invention Distribution graph explaining the distribution of the front and rear signal values and the threshold function for the seated sample Distribution graph explaining distribution of front signal value and rear signal value and threshold function by seating sample in another form of seating detection device Further, a distribution graph for explaining the distribution of the front signal value and the rear signal value by the seating sample and the threshold function in another form of the seating detection device The partial cross section perspective view which shows the whole seat seat by which the seating detection apparatus of this invention is mounted Functional block diagram showing the electrical configuration of the seating detection device Plan view and side sectional view showing the structure of the pressure sensitive cell Explanatory diagram showing the relationship between the child / child seat area and adult area and the threshold function Functional block diagram showing the electrical configuration of the seating detection device in another embodiment Explanatory drawing which shows the relationship between the child and child seat area | region, adult area | region, and threshold value function in another embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seating surface 10 Pressure sensitive cell 20 Pressure sensor 20A Front pressure sensor unit 20B Rear pressure sensor unit 40 Measurement electronic system 50 Evaluation electronic system (determination part)
51 Threshold LUT
FS Front signal value RS Rear signal value

Claims (5)

In a seating detection apparatus comprising: a pressure-sensitive sensor comprising a plurality of pressure-sensitive cells disposed on a seating surface of a seat; and a determination unit that determines a seating object in the seat based on a signal from the pressure-sensitive sensor.
The pressure-sensitive sensor includes a front pressure-sensitive sensor unit including a plurality of pressure-sensitive cells disposed in a front region of the seating surface, and a rear pressure sensor including a plurality of pressure-sensitive cells disposed in a rear region of the seating surface. The determination unit is configured to determine a seating object on the seat based on a correlation between a front signal value from the front pressure sensor unit and a rear signal value from the rear pressure sensor unit. A seating detection device.   A pressure-sensitive cell constituting the front pressure-sensitive sensor unit and a pressure-sensitive cell constituting the rear pressure-sensitive sensor unit are electrically connected to each other in the central region of the seating surface. The seating detection apparatus according to claim 1.   The seating detection device according to claim 1 or 2, wherein a pressure-sensitive cell to which a larger load is applied when an adult is seated is configured to have a higher pressure-sensitive output performance than other pressure-sensitive cells.   The pressure-sensitive cell that is subjected to a larger load when a child is seated or a child seat is installed is configured with a pressure-sensitive output performance lower than that of other pressure-sensitive cells. A seating detection device according to any one of the above.   The arrangement of the pressure-sensitive cell in the center of gravity region of the child or child seat on the seating surface when the child is seated or when the child seat is installed is omitted. The seating detection apparatus described in 1.

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