METHOD AND DEVICE FOR PROCESSING DATA ASSOCIATED WITH A SIGNAL

Abstract

A computer-implemented method for processing data which are associated for example with a signal transmittable and/or transmitted via a bus system, for example of a vehicle, including: at least intermittent provision of reference data for a statistical model which characterizes at least one average of at least one characteristic of the signal on the basis of a first average determined, for example dynamically, over a predefinable unweighted first number of values for the characteristic, and at least intermittent modification of the reference data at least in part on the basis of a second average determined, for example dynamically, over a predefinable weighted second number of values for the characteristic.

Claims

1. A computer-implemented method for processing data which are associated with a signal transmittable and/or transmitted via a bus system, comprising the following steps: at least intermittently providing reference data for a statistical model which characterizes at least one average of at least one characteristic of the signal, based on a first average determined over a predefinable unweighted first number of values for the characteristic; and at least intermittently modifying the reference data based at least in part on a second average determined over a predefinable weighted second number of values for the characteristic.

2. The method as recited in claim 1, wherein the bus system is a bus system of a vehicle.

3. The method as recited in claim 1, wherein the statistical model additionally characterizes a standard deviation of the at least one characteristic of the signal.

4. The method as recited in claim 3, wherein the providing of the reference data includes: determining the standard deviation of the at least one characteristic of the signal based on the first average determined over the predefinable unweighted first number of values for the characteristic.

5. The method as recited in claim 3, wherein the modifying of the reference data includes: determining the standard deviation of the at least one characteristic of the signal based on the first average determined over the predefinable unweighted second number of values for the characteristic.

6. The method as recited in claim 1, further comprising: predefining a weighting factor for the modifying of the reference data.

7. The method as recited in claim 1, further comprising: $M_i^k=M_{i-1}^k+\frac{c_i^k-M_{i-1}^k}{i}{c}_i^k{M}_i^k{c}_i^{k}1<i\le \mathrm{mm}$ forming the first average determined over the predefinable unweighted first number of values for the characteristic according to: $M_i^k=M_{i-1}^k+\frac{c_i^k-M_{i-1}^k}{i}{c}_i^k{M}_i^k{c}_i^{k}1<i\le mm$ wherein characterizes an i.sup.th measured value of the characteristic for a k.sup.th source, wherein is an average for the k.sup.th source associated with the i.sup.th value, for, wherein characterizes a number of values for providing of the reference data.

8. The method as recited in claim 1, further comprising: forming the second average determined over the predefinable weighted first number of values for the characteristic according to: M.sub.k.sup.k=ω.Math.M.sub.j−1.sup.k+(1−ω).Math.c.sub.j.sup.k, wherein c.sub.j.sup.k characterizes a j.sup.th measured value, of the characteristic for a k.sup.th source, wherein M.sub.j.sup.k is an average for the k.sup.th source associated with the j.sup.th value c.sub.j.sup.k, and wherein ω characterizes a weighting factor.

9. A device configured to process data which are associated with a signal transmittable and/or transmitted via a bus system, the device configured to: at least intermittently provide reference data for a statistical model which characterizes at least one average of at least one characteristic of the signal, based on a first average determined over a predefinable unweighted first number of values for the characteristic; and at least intermittently modify the reference data based at least in part on a second average determined over a predefinable weighted second number of values for the characteristic.

10. A control device a vehicle, comprising: at least one device configured to process data which are associated with a signal transmittable and/or transmitted via a bus system, the device configured to: at least intermittently provide reference data for a statistical model which characterizes at least one average of at least one characteristic of the signal, based on a first average determined over a predefinable unweighted first number of values for the characteristic; and at least intermittently modify the reference data based at least in part on a second average determined over a predefinable weighted second number of values for the characteristic.

11. A non-transitory computer-readable storage medium on which are stored commands for processing data which are associated with a signal transmittable and/or transmitted via a bus system, the commands, when executed by a computer, causing the computer to perform the following steps: at least intermittently providing reference data for a statistical model which characterizes at least one average of at least one characteristic of the signal, based on a first average determined over a predefinable unweighted first number of values for the characteristic; and at least intermittently modifying the reference data based at least in part on a second average determined over a predefinable weighted second number of values for the characteristic.

12. The method as recited in claim 1, wherein the method is used for: (i) providing an intrusion detection system and/or intrusion detection and prevention system, or (ii) authenticating and/or identification of a transmitter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 schematically shows a simplified flow chart of a method according to exemplary embodiments of the present invention.

[0028] FIG. 2 schematically shows a simplified block diagram according to further exemplary embodiments of the present invention.

[0029] FIG. 3 schematically shows a simplified block diagram according to further exemplary embodiments of the present invention.

[0030] FIG. 4 schematically shows a simplified flow chart according to further exemplary embodiments of the present invention.

[0031] FIG. 5 schematically shows a simplified flow chart according to further exemplary embodiments of the present invention.

[0032] FIG. 6 schematically shows a simplified block diagram according to further exemplary embodiments of the present invention.

[0033] FIG. 7 schematically shows aspects of uses according to further exemplary embodiments of the present invention.

[0034] FIG. 8 schematically shows a diagram according to further exemplary embodiments of the present invention.

[0035] FIG. 9 schematically shows a diagram according to further exemplary embodiments of the present invention.

[0036] FIG. 10 schematically shows a diagram according to further exemplary embodiments of the present invention.

[0037] FIG. 11 schematically shows a simplified block diagram according to further exemplary embodiments of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0038] Exemplary embodiments, cf. FIGS. 1, 2, relate to a method, for example a computer-implemented method, for processing data which, for example, are associated with a signal SIG (FIG. 2) transmittable and/or transmitted, via a bus system 10, for example of a vehicle 20 (FIG. 11), including: at least intermittent provision 100 (FIG. 1) of reference data RD for a statistical model MOD, see FIG. 3, which characterizes at least one average M-C of at least one characteristic C of the signal SIG, on the basis of a first average M-C-RD (FIG. 1) determined, for example dynamically, over a predefinable unweighted first number of values for the characteristic C, and at least intermittent modification 102 of the reference data RD at least in part on the basis of a second average M-C-RD′ determined, for example dynamically, over a predefinable weighted second number of values for the characteristic C.

[0039] In further exemplary embodiments, this enables e.g. efficient formation 100 of the reference data RD, e.g. online, thus dynamically, thus during operation e.g. of the bus system 10 which is usable for transmission of the signal SIG, thus for example when messages are sent via the bus system 10, and/or efficient adaptation of the reference data RD e.g. to changing environmental conditions or other variables (e.g. temperature, humidity, etc.) which may have an influence on the signal SIG or the characteristic C.

[0040] In further exemplary embodiments, the signal SIG may for example be characterized by a time profile of an electrical voltage and/or an electrical current, such as are transmittable e.g. via a transmission medium (e.g. including one or more bus lines, not shown) of the optional bus system 10.

[0041] In further exemplary embodiments, the signal SIG may also be transmittable or transmitted other than via the bus system 10 stated by way of example, for example in general via at least one transmission medium which may for example be wired or wireless or may include combinations of wired and/or wireless transmission media.

[0042] In further exemplary embodiments, the at least one characteristic C of the signal SIG may characterize for example a) a, for example temporal, fluctuation of the signal SIG or of at least some components (e.g. frequency components or time components) of the signal SIG, for example a clock skew, and/or b) a difference in transition times which are observable for state changes of the signal SIG, for example from a first signal state or level to a second signal state or level and vice versa, and/or c) a time difference between a first point in time and a second point in time, wherein, at the first point in time, a signal output by a transmitter 1 (FIG. 2) on the transmission medium of the bus system 10 reaches a first position with regard to the transmission medium, wherein, at the second point in time, the signal SIG output by the transmitter 1 on the transmission medium of the bus system 10 reaches a second position with regard to the transmission medium, etc. In further exemplary embodiments, other characteristics of the signal SIG may alternatively or additionally also be considered or e.g. a corresponding respective average characterized by the model MOD.

[0043] In further exemplary embodiments, the at least one characteristic C of the signal SIG e.g. characteristic of a transmitter 1 or a source Q-k of the signal SIG, for example a bus station, e.g. a control device of a vehicle 20 (FIG. 11). In further exemplary embodiments, the at least one characteristic C or the model MOD may accordingly be used e.g. to identify a transmitter 1 or a source Q-k, for example in a further control device or in general receiver 2 which can receive the signal SIG sent via the bus system 10.

[0044] Further exemplary embodiments provide that the statistical model MOD additionally (to the average M-C) characterizes a standard deviation SD-C (FIG. 3) of the at least one characteristic C (FIG. 2) of the signal SIG.

[0045] Further exemplary embodiments, FIG. 1, provide that provision 100 of the reference data RD includes: determination 100a of the standard deviation SD-C of the at least one characteristic C of the signal SIG on the basis of the first average M-C-RD determined, for example dynamically, over the predefinable unweighted first number of values for the characteristic C.

[0046] Further exemplary embodiments, FIG. 1, provide that modification of 102 the reference data RD includes: determination 102a of the standard deviation SD-C of the at least one characteristic C of the signal SIG on the basis of the first average M-C-RD determined, for example dynamically, over the predefinable unweighted second number of values for the characteristic. In other words, some exemplary embodiments provide that the average M-C-RD for the reference data RD is formed differently (e.g. in unweighted manner) from the average M-C-RD′ for modifying 102 the reference data RD (the latter being formed e.g. in weighted manner), whereas the standard deviation SD-C of the at least one characteristic C is formed e.g. independently of the reference (provision 100 of the reference data RD or modification 102 of (the already provided) reference data RD).

[0047] Further exemplary embodiments, FIG. 4, provide that the method includes: predefinition 110 of a weighting factor GF, for example for modifying 102 (FIG. 1) the reference data RD. In further exemplary embodiments, the weighting factor GF may e.g. also be varied dynamically, i.e. during modification 112 of the reference data RD or the corresponding average m-C-RD′, whereby modification of the average of the model MOD may be controlled flexibly e.g. during use of the model MOD.

[0048] Further exemplary embodiments, FIG. 5, provide that the method includes: formation 120 of the first average M-C-RD determined over the predefinable unweighted first number of values for the characteristic C according to:

[00003]$M_i^k=M_{i-1}^k+\frac{c_i^k-M_{i-1}^k}{i},$

wherein c.sub.i.sup.k characterizes an i.sup.th value, for example measured value (and/or value determined by calculation and/or formed in another manner), of the characteristic C for a k.sup.th source Q-k (FIG. 2), for example a k.sup.th control device, wherein M.sub.i.sup.k is the average for the k.sup.th source associated with the i.sup.th value c.sub.i.sup.k, wherein for example 1<i≤m, wherein m characterizes a number of values for provision of the reference data. For example, in this variant, the first average M-C-RD associated with the current, i.sup.th value of the characteristic C is therefore based on the average M.sub.i−1.sup.k associated with the (i−1).sup.th value of the characteristic, on the index variable i, and on the i.sup.th value c.sub.i.sup.k of the characteristic C, such that comparatively little memory and comparatively few computing time resources are used for the determination. In particular, it is not necessary in exemplary embodiments to store numerous, e.g. all, preceding values c.sub.i−1.sup.k, c.sub.i−2.sup.k, . . . or M.sub.i−2.sup.k, M.sub.i−3.sup.k, . . . etc.

[0049] Further exemplary embodiments, FIG. 5, provide that the method includes: formation 122 of the second average M-C-RD′ determined, for example dynamically, over a predefinable weighted second number of values for the characteristic C according to: M.sub.j.sup.k=ω.Math.M.sub.j−1.sup.k+(1−ω).Math.c.sub.j.sup.k, wherein c.sub.j.sup.k characterizes a j.sup.th value, for example measured value, of the characteristic for a k.sup.th source, for example a k.sup.th control device, wherein M.sub.j.sup.k is the average for the k.sup.th source associated with the j.sup.th value c.sub.j.sup.k, and wherein ω characterizes a or the weighting factor GF (FIG. 4) such that comparatively little memory and comparatively few computing time resources are used for the determination. In particular, it is not necessary in exemplary embodiments to store numerous, e.g. all, preceding values c.sub.j−1.sup.k, c.sub.j=2.sup.k, . . . or M.sub.j−2.sup.k, M.sub.j−3.sup.k, . . . etc.

[0050] Further exemplary embodiments provide that the standard deviation SD-C is formed according to the following equations:

[00004]$\begin{array}{c}{V}_i^k=V_{i-1}^k+\left(c_i^k-M_{i-1}^k\right)\times \left(c_i^k-M_i^k\right)\\ S_i^k=\sqrt{\frac{V_i^k}{i-1}}\end{array},$

[0051] wherein V.sub.i.sup.k is an operand which is based on the first average M.sub.i.sup.k or M-C-RD, for example formed according to equation

[00005]$M_i^k=M_{i-1}^k+\frac{c_i^k-M_{i-1}^k}{i},$

and on the i.sup.th value c.sub.i.sup.k, for example measured value, of the characteristic C for a k.sup.th source Q-k (FIG. 2), wherein S.sub.i.sup.k is the standard deviation.

[0052] In further exemplary embodiments, e.g. M.sub.1.sup.k=c.sub.1.sup.k, and/or V.sub.1.sup.k=0 and/or S.sub.1.sup.k=0 and/or M.sub.j−1.sup.k=M.sub.m.sup.k and/or m<j apply.

[0053] The principle according to the embodiments may advantageously be used to provide reference data RD for statistical models MOD which characterize for example at least one average of at least one characteristic C of the signal SIG. The principle according to the embodiments is also applicable to models MOD or to reference data RD for models MOD which characterize a plurality of characteristics C of one or more signals SIG, wherein characteristics C or the signals SIG characterize e.g. physical properties of at least one transmitter 1 or source Q-k.

[0054] For example, the principle according to the embodiments is applicable to such models which are usable for identifying and/or detecting, e.g. intrusions into the bus system 10, e.g. by tampering with an existing transmitter 1 or by inserting an unauthorized transmitter (not shown). For example in further exemplary embodiments, a provision phase may be provided in which the reference data RD for the model MOD are provided, for example by way of block 100 according to FIG. 1.

[0055] In further exemplary embodiments, the reference data RD may e.g. include an average for a characteristic C of the signal SIG or a standard deviation for the characteristic C of the signal SIG, as can be determined e.g. during regular operation of the bus system, e.g. in the provision phase. In further exemplary embodiments, these values can then be used as reference data RD e.g. for an operating phase following the provision phase. In order to adapt the reference data RD to any possibly present environmental influences (temperature, humidity, etc.) which may e.g. also have an influence on the signal SIG or its waveform, the modification 102 of the reference data RD obtained according to block 100 may be carried out in further exemplary embodiments.

[0056] For example, assuming use of the principle according to the embodiments in a motor vehicle 20 (FIG. 11), provision 100 (FIG. 1) of the reference data RD may for example proceed on starting the motor vehicle 20, in order for example to obtain reference data RD which are valid for the current operation and current operating conditions of the motor vehicle 20. Provision 100 may, for example, proceed on the basis of m many values of the characteristic C, wherein, after provision as reference data RD e.g. the average M-C-RD and, optionally the standard deviation SD-C (for example formable on the basis of the average M-C-RD) are available. In further exemplary embodiments, after the provision phase (directly thereafter or a predefinable time later or repeatedly, e.g. periodically), the currently available reference data RD may be adapted, for example by way of the modification 102 according to FIG. 1. This provides modified reference data RD′ which are adapted to the further operation of the motor vehicle 20.

[0057] Further exemplary embodiments, FIG. 6, relate to a device 200 for carrying out the method according to the embodiments. For example, in further exemplary embodiments, the device 200 may take the form of a control device 200′, e.g. for a motor vehicle 20 (FIG. 11), or be integrated into a control device 200′, e.g. for a motor vehicle 20.

[0058] The device 200 includes a computing device (“computer”) 202 having at least one computing core 202a, 202b, 202c and a storage device 204 associated with the computing device 202 for at least temporary storage at least one of the following elements: a) data DAT e.g. of the model MOD, e.g. the reference data RD or the modified reference data RD′ or data characterizing the signal SIG, b) computer program PRG, in particular for carrying out a method according to the embodiments.

[0059] In further exemplary embodiments, the storage device 204 includes a volatile memory 204a (e.g. working memory (RAM)) and/or a nonvolatile memory 204b (e.g. flash EEPROM).

[0060] In further exemplary embodiments, the computing device 202 includes or takes the form of at least one of the following elements: microprocessor (μP), microcontroller (μC), application-specific integrated circuit (ASIC), system on chip (SoC), programmable logic chip (e.g. field programmable gate array (FPGA)), hardware circuit, or any desired combinations thereof.

[0061] Further exemplary embodiments relate to a computer-readable storage medium SM comprising commands PRG which, on execution by a computer 202, cause the latter to carry out the method according to the embodiments.

[0062] Further exemplary embodiments relate to a computer program PRG comprising commands which, on execution of the program by a computer 202, cause the latter to carry out the method according to the embodiments.

[0063] Further exemplary embodiments relate to a data carrier signal DCS which transmits and/or characterizes the computer program PRG according to the embodiments. The data carrier signal DCS is receivable, for example, via an optional data interface 208 of device 200 via which e.g. the signal SIG data is also receivable.

[0064] Further exemplary embodiments, FIG. 11, relate to a control device 200′, for example for a vehicle, for example motor vehicle, 20 including at least one device 200 (FIG. 6) according to the embodiments.

[0065] Further exemplary embodiments, FIG. 7, relate to a use 300 of the method according to the embodiments and/or of the device 200 according to the embodiments and/or of the control device 200′ according to the embodiments and/or of the computer-readable storage medium SM according to the embodiments and/or of the computer program PRG according to the embodiments and/or of the data carrier signal DCS according to the embodiments for at least one of the following elements: a) provision 301 of reference data RD for a statistical model MOD, b) modification 302, for example dynamic adaptation, of the reference data RD for the statistical model MOD, c) provision 303 of an intrusion detection system and/or intrusion detection and prevention system, d) authentication 304 and/or identification of a transmitter 1, Q-k (FIG. 2).

[0066] FIG. 8 is a schematic diagram of the effect of, for example external, influences such e.g. weather or temperature on signals from various transmitters. A total of five unlabeled curves are shown, for example in each case characterizing a characteristic of a respective signal SIG which is transmittable via the bus system 10 (FIG. 2), wherein the characteristic for example characterizes a time difference with regard to the signal SIG. The fluctuations of the vertically plotted time differences occurring along a horizontal axis, which characterizes e.g. a time profile or a number of received data frames with regard to the signal, are clearly apparent. This means e.g. that individual characteristics C which are characteristic of individual transmitters 1 may very well be subject to non-vanishing fluctuation which may impair precision in the case of evaluation on the basis of a statistical model MOD. These disadvantages can e.g. be at least temporarily mitigated in exemplary embodiments.

[0067] FIG. 9 shows an exemplary comparison of different approaches to adapting an average of a characteristic of a signal SIG. Curve K1 characterizes the signal SIG, curve K2 characterizes the, for example unweighted, first average M-C-RD, curve K3 characterizes the, for example weighted, second average M-C-RD′, and curve K4 characterizes a constant plotted along a horizontal time axis. It is apparent that the weighted, second average M-C-RD′ follows the signal curve K1 comparatively well, in particular more quickly than the unweighted average K2, so enabling efficient adaptation of the reference data RD or RD′ e.g. to changed environmental conditions.

[0068] FIG. 10 shows examples of standard deviations according to various approaches. Element E1 characterizes the standard deviation of the signal SIG itself, cf. e.g. curve K1 according to FIG. 9. Element E2 characterizes the standard deviation determined on the basis of the first (unweighted) average M-C-RD, cf. e.g. curve K2 according to FIG. 9. Element E3 characterizes the standard deviation determined on the basis of the second (weighted) average M-C-RD′, cf. e.g. curve K3 according to FIG. 9. It is apparent that the standard deviation E3 remains comparatively small and constant, which in further exemplary embodiments indicates good adaptability of the method or device 200 and thus enables e.g. reliable identification of a transmitter 1 or good intrusion detection, event in the event of changing external conditions such as for example temperature fluctuations.