Abstract: A vibration dosimeter (2) for determining the vibrational loading of people includes a determination device (6) for determining the operating period duration, a calculation device (6) for calculating the permitted work time as a function of a tool-specific characteristic vibration value, a comparison device (6) for comparing the effective operating period duration with the permitted work time, and an interface (3) for reading in the characteristic vibration value from the tool (1).

Abstract: A method for automated startup and/or for automated operation of controllers of an electrical drive system with vibrational mechanics with the following steps: (a) determining a preliminary value of at least one parameter; (b) determining a model of the electrical drive system by determination of initially a non-parameterized model through the recording of frequency data during operation of the drive system subject to the utilization of the preliminary value of at least one parameter and the subsequent determination of parameters of the electrical drive system based on the frequency data and subject to optimization of at least one preliminary value of at least one parameter by a numerical optimization method on the basis of the Levenberg-Marquardt algorithm and (c) parameterizing at least one controller of the electrical drive system by at least one of the determined parameters.

Abstract: Principles of the invention provide methods and apparatus for providing corrosion management in buildings. In one aspect, an exemplary method includes the step of receiving first data relating corrosion rate to a plurality of environmental conditions. This first data is subsequently utilized to determine a quantitative relationship between corrosion rate and the plurality of environmental conditions. In another step, second data indicative of one or more environmental conditions within a building is received. A corrosion rate in the building is then determined at least in part by applying the determined quantitative relationship to this second data.

Abstract: This invention relates to a method for determining a wear state of a chisel, a chisel holder, and/or a chisel holder replacement system equipped with a chisel and chisel holder. For this method to give the user qualitative and quantitative information about the wear, according to one embodiment of this invention, a position of at least one point of the chisel and/or the chisel holder is determined by a contactless measurement method and a corresponding measurement result is compared in a switching unit to a reference value stored in a memory device.

Abstract: A two-dimensional map for calculating an SOC of a secondary battery is corrected. A battery ECU obtains a voltage index of a secondary battery. The voltage index is, for example, a no-load voltage of the secondary battery. When an amount of change of the calculated no-load voltage from an initial state falls outside a predefined range, the battery ECU corrects the two-dimensional map of initial state which is stored in advance in a storage unit using data obtained by statistically processing a plurality of two-dimensional maps obtained from a plurality of vehicles.

Abstract: Determining health of a component includes using at least one processor to perform processes including acquiring a plurality of measured values corresponding to the condition indicators. Synchronous noise components are removed from the measured values to provide revised measured values, and the revised measured values are used to determine noise-filtered condition indicator values. The noise-filtered condition indicator values may be used in algorithms to determine the health of the component. Removing synchronous noise components may include determining a predicted value thereof using covariance and autocovariance of the measured values. The component may be a split torque gearbox.

Abstract: A damage detection apparatus and method which detect a damage occurring in a specimen include energizing an inspection area on a specimen into a predetermined energized condition, measuring a potential difference at predetermined intervals in the inspection area, and analyzing an existence or otherwise of a damage, and a shape thereof, based on a plurality of items of potential difference data. Parameters specifying a hypothetical damage are hypothesized in advance and, based on the potential difference data, calculation is executed using a maximum likelihood estimation method on a double body in which hypothetical specimens are doubled by bringing together their front surfaces, and furthermore on a quadruple body quadrupled by bringing rear surfaces of hypothetical specimens together, a maximum likelihood estimation value of the parameters is calculated.

Abstract: In one aspect of the present invention, a system has a data acquisition device for acquiring data from a component. The component has an identification transmitter. The data acquisition device has an image acquisition mechanism to capture an image of the component and a receiver to receive a signal from the identification transmitter. The data acquisition device also has a processor to process data from the image acquisition mechanism and the receiver.

Abstract: In one aspect of the present invention, a system has a data acquisition device for acquiring data from a component. The component has an identification transmitter. The data acquisition device has an image acquisition mechanism to capture an image of the component and a receiver to receive a signal from the identification transmitter. The data acquisition device also has a processor to process data from the image acquisition mechanism and the receiver.

Abstract: A hydraulic aggregate for supplying a hydraulic cylinder in consecutive load strokes is monitored for its working load in order to determine the condition of the aggregate automatically. For this purpose, the time integral of the pressure is determined for each load stroke. The pressure and duration are processed into a characteristic number which indicates the wear. This makes it possible to diagnose the condition of the hydraulic aggregate at any time.

Abstract: A method by which physical properties, including the Young's modulus and thermal conductivity of a ceramic layer of a thermal barrier coating formed on a high-temperature member, are quickly and accurately estimated. A method for estimating a physical property of a ceramic includes a step of calculating the Larson-Miller parameter from the time for which and the temperature at which the ceramic is heated; a step of acquiring the porosity of the ceramic corresponding to the calculated Larson-Miller parameter, based on the calculated Larson-Miller parameter and a diagram correlating the Larson-Miller parameter and the porosity obtained from samples having the same composition as the ceramic; and a step of acquiring the physical property of the ceramic corresponding to the acquired porosity, based on the acquired porosity and a diagram correlating the porosity and the physical property obtained from samples having the same composition as the ceramic.

Abstract: A robotic system includes a humanoid robot with multiple compliant joints, each moveable using one or more of the actuators, and having sensors for measuring control and feedback data. A distributed controller controls the joints and other integrated system components over multiple high-speed communication networks. Diagnostic, prognostic, and health management (DPHM) modules are embedded within the robot at the various control levels. Each DPHM module measures, controls, and records DPHM data for the respective control level/connected device in a location that is accessible over the networks or via an external device. A method of controlling the robot includes embedding a plurality of the DPHM modules within multiple control levels of the distributed controller, using the DPHM modules to measure DPHM data within each of the control levels, and recording the DPHM data in a location that is accessible over at least one of the high-speed communication networks.

Abstract: Machine vibration baselines are synthesized without averaging historical vibration data. Instead machinery configuration information is used, including data about the machine train, the machine's rotating components, and the machine speeds. For each component being considered, a plurality of parameters is identified for deriving baseline portions. The parameters for one component are used to identify baseline vibration amplitude floor values, vibration amplitudes at frequencies corresponding to various harmonics of a rotational speed, and vibration amplitudes corresponding to forcing frequencies and their harmonics/sidebands. Parameters for other components also may be used to identify amplitudes at harmonic frequencies and forcing frequencies.

Abstract: A reciprocating pump system is utilized. The system facilitates the prediction of failure modes due to degradation of pump components. A sensor system is used to monitor parameters indicative of abnormal events or wear occurring in specific components, such as pump valves. The indications of wear can be used to predict valve failure or other component failure within the reciprocating pump.

Abstract: A system and method are provided to monitor the health of a wind turbine gearbox. The system includes a plurality of sensors coupled to the wind turbine gearbox and a controller coupled to the plurality of sensors. The controller is configured to acquire vibration information from a vibration sensor, acquire a tachometer signal, convert the tachometer signal and the vibration information into a cycle domain signal, and perform an order analysis on the cycle domain signal, the order analysis providing information that identifies potential and actual damage within the wind turbine gearbox.

Abstract: An apparatus for checking insulation of a cell module assembly composed of a plurality of pouch cells includes a first probing unit electrically contacted to an electrode of the cell module assembly; a second probing unit electrically contacted to aluminum films of selected ones of the pouch cells in the cell module assembly; and a measuring unit for measuring an insulation resistance between the first probing unit and the second probing unit. This apparatus may measure insulation resistances of a plurality of pouch cells of the cell module assembly at once, thereby ensuring faster insulation checking.

Abstract: A method for predicting mechanical failure of a traction motor in a vehicle includes monitoring first characteristics of an electrical signal supplied to a traction motor of a vehicle during a first detection window. The first characteristics represent a first motor electrical signature for the traction motor. The method also includes deriving one or more signature values from a first mathematical model of the first motor electrical signature and predicting a mechanical failure of the traction motor based on the one or more signature values.

Abstract: An effective value operation unit calculates an effective value of a vibration waveform of a hearing, the vibration waveform being measured by using a vibration sensor. An envelope processing unit performs envelope processing on the vibration waveform measured by using the vibration sensor, thereby generating an envelope waveform of the vibration waveform. An effective value operation unit calculates an effective value of an AC component of the envelope waveform generated by the envelope processing unit. A diagnostic unit diagnoses an abnormality of the bearing based on the effective value of the vibration waveform calculated by the effective value operation unit and the effective value of the AC component of the envelope waveform calculated by the effective value operation unit.

Abstract: The present invention relates to systems and methods for real-time health monitoring of engines to monitor turbomachinery blades during engine operation and report anomalous behavior and shape of the blades if it occurs, such as damage by FOD. The system comprises sensor(s) for obtaining a blade reflection profile from a blade passing by the sensor(s) during a revolution of the rotor in combination with a processor for performing timing calculations and/or fingerprint comparisons with reference data to identify a change in blade fingerprint relative to the reference data, which may indicate blade damage. Such systems can reduce operational costs, enhance safety and improve operational readiness by facilitating condition-based maintenance of engine rotors as opposed to schedule-based solutions. The invention can prevent the needless loss of life and assets caused by undetected minor levels of blade damage that may lead to unexpected catastrophic failure of an engine.

Abstract: Included are a testing step (S1) for determining the relation between the shear stress amplitude of a rolling contact metallic material and the number of loading by means of an ultrasonic torsional fatigue test, and a shear fatigue strength determining step (S2) for determining the shear fatigue strength ?lim, within the ultra long life regime from the relation between the shear stress amplitude and the number of loadings, which relation has been determined during the test step (S1), in accordance with a predetermined standard. It is a completely reversed torsional fatigue test, in which torsional vibrations, respective torsions in the positive rotational direction and reversed rotational direction of which are symmetrical relative to each other, are applied to a test piece (1).

Abstract: There is provided a sensor equipped wheel support bearing assembly including an outer member having an inner periphery formed with a plurality of rolling surfaces defined therein, an inner member having an outer periphery formed with rolling surfaces opposed to those rolling surfaces and a plurality of rows of rolling elements interposed between those rolling surfaces. One of the outer and inner members serving as a stationary member is provided with a strain amplifying mechanism for amplifying a strain in the stationary member, which occurs when the rolling elements pass by. A strain sensor element is provided for detecting the strain amplified by the strain amplifying mechanism. A calculator is provided for calculating from an output of the strain sensor element, the load acting on the bearing assembly or the load acting between the vehicle wheel and the road surface.

Abstract: A method is provided for evaluating simultaneously the effects of multiple, interdependent heat-exchanger degradation modes for a heat exchanger of a power plant in the context of a series of alternative heat-exchanger remediation strategies. The method includes calculating time-varying predicted future progressions of heat exchanger performance metrics for a plurality of alternative heat-exchanger remediation strategies, and calculating time-varying predicted future progressions of financial metrics describing the accumulated financial benefit of each of the strategies. The calculations may be provided in probabilistic terms. A strategy may then be chosen based, at least in part, on the calculated results.

Abstract: One embodiment of the present invention provides a system for predicting a remaining useful life (RUL) for a component in a set of components within a computer system. The system starts by collecting values of at least one degradation-related parameter associated with the operation of a monitored component within the computer system. Note that the degradation-related parameter is a direct measurement of a degree of degradation of the monitored component. The system additionally collects values of at least one stress-based parameter from the computer system. Note that the stress-based parameter measures an accumulative stress in the operating environment of the set of components which can cause degradation of the set of components. The system then uses the values of the at least one degradation-related parameter and the values of the at least one stress-based parameter to predict an RUL for a component in the set of components.

Abstract: A method for estimating a fan life includes the following steps. Fans to be checked at a number of M are provided. A working temperature and a test temperature of a fan are set, and the test temperature is greater than the working temperature. An acceleration factor is set, which has a fixed value. The fans are kept in an operating state at the test temperature, and a number of the damaged fans is detected and recorded at intervals of a check time, until N damaged fans are detected. A distribution of time points when the fans are damaged is simulated with a Weibull distribution model, and a shape parameter and a characteristic life of the Weibull distribution model are calculated. A life value of the fans at the test temperature is calculated. A life value of the fans at the working temperature is calculated by using the acceleration factor.

Abstract: A method for detecting changes in a building structure of a first wind turbine is provided. A reference value representing the eigenfrequency of the first wind turbine is monitored over time, whereby substantial changes in the reference value are used as an indication of changes in the building structure. Further, a detection assembly for such detections is provided.

Abstract: A system model of a real-world system includes a multi-level hierarchy of Capabilities, where each Capability includes a Verb specifying an action and an Object acted on by the Verb. The system model also contains one or more multi-level Performer hierarchies, where each Performer hierarchy includes a plurality of Performers each having an associated lifecycle and at least one associated Capability provided or required by the Performer. In addition, a multi-level Location hierarchy associates one of a plurality of Locations with each Performer. A plurality of Capability Instances define requirement and provision of Capabilities by Performers in the one or more multi-level Performer hierarchies. In response to a query specifying a Location and a time, a view of the system model for the specified Location and time is output.

Abstract: A method for determining the evolution of torque of at least one rotatable shaft and the resulting fatigue damage to different power train components is provided for design and/or maintenance operations in a wind turbine that comprises the steps of determining torque (Tg) at a high speed shaft of the power train; determining moment of inertia (Ig) at the high speed shaft; determining angular acceleration (?g) at the high speed shaft; and determining torque (Tr) at the low speed shaft of the power train through the formula Tr=(Tg?Ig ?g)·i. A rainflow-counting algorithm may be applied to the value of the torque (Tr) at the low speed shaft for determining the number of cycles at ranges of torque for every torque mean value.

Abstract: A method and system for incorporating electronic signature analysis in a low voltage power supply to centrally monitor current consumption is disclosed. The electrical loads powered by the low voltage power supply can be tested individually via an automatic test routine by measuring and scaling of current through a differential amplifier. The current consumption of each electrical load can be measured by analyzing a “delta” in the current draw of each electrical load's ON and OFF condition. This value can be compared against a stored table of high and low limits for each electrical load. If a load's current is outside the limits, it will be logged for repairs. A current sensing device can be inserted in series with the output(s) of the low voltage power supply, while in test mode, to allow the automatic test routine to run, and then be shorted out for normal operation.

Abstract: A control device includes a transmission unit including a first gear rotating with a motor shaft and a second gear rotating with a rotating roller which drives a rotated body, a speed detecting unit for detecting the rotational speed of the rotated body or rotating roller, a motor controlling unit for maintaining a constant motor shaft rotational speed based on the rotational speed, a converting unit for converting the rotational speed to a relationship between a frequency contained in a variation of the rotational speed in association with time and a variation value of the rotational speed, and a wear detecting unit for detecting a predictor of wear of cogs in at least one of the first and second gears when the variation value at a specified frequency, determined based on the number of the cogs of the first gear and the motor shaft rotational speed, exceeds a threshold value.

Abstract: A diagnosis system and method to detect wear between a first set of teeth of a first gear and a second set of teeth of a second intermeshing gear, the diagnosis system having a first target associated with the first set of teeth, a second target associated with the second set of teeth, a first sensor adapted to detect the location of the first target, a second sensor adapted to detect the location of the second target, and a processing system in data communication with the first sensor and the second sensor, the processing system being adapted to process a spatial relationship between the first target relative to the second target after a time lapse of rotation between the first set of teeth and the second set of teeth.

Abstract: A method and system are provided to reconstruct vibration responses such as stress and fatigue damage at desired locations in a structure from a limited number of vibration measurements at a few locations in the structure. Vibration response measurements can be of any type, e.g. acceleration, angular velocity, strain, etc. The desired locations can be anywhere within the domain of the structure and may include the entire structural domain. Measured vibration responses may be of uniform type or combinations of different types.

Abstract: A dummy junction which will break earlier than a target junction is arranged on a board. A history of load applied to the dummy junction until the dummy junction actually breaks is recorded, and an estimated lifetime of the target junction is calibrated when a lifetime of the dummy junction estimated by the history of the load is largely different from an actual lifetime of the dummy junction. The calibration is performed by subtracting a value of an unmeasurable load from the estimated lifetime of the target junction based on load ever applied to the target junction, and the unmeasurable load is calculated based on the difference of the actual lifetime and estimated lifetime of the dummy junction.

Abstract: Systems and methods are described to receive a safety preference; calculate a temporary route; analyze a portion of the temporary route to determine whether the portion is sufficiently safe based on the safety preference; modify the portion of the temporary route when the portion is not sufficiently safe; and present the temporary route. Other systems and methods are described.

Abstract: Certain embodiments of the invention may include systems, methods, and apparatus for determining online stress and life consumption of a heat recovery steam generator (HRSG). According to an example embodiment of the invention, a method for assessing components of a HRSG is provided. The method includes receiving HRSG design parameters; determining thermal stress data associated with the one or more HRSG components based at least in part on one or more historical, real-time, or calculated temperature sensor data associated with the one or more HRSG components; and determining cycle-related life consumption data associated with the one or more HRSG components based at least in part on the HRSG design parameters and the determined thermal stress data.

Abstract: A process automation system for determining, monitoring and/or influencing different process variables and/or state variables in at least one manufacturing or analytical process. Included is: at least one control station; and a plurality of field devices; wherein in each field device at least one sensor is provided for ascertaining a measured value of a process variable and/or state variable and/or an actuator is provided for influencing a process variable and/or state variable by means of an actuating value. Each field device makes available its cyclically or acyclically ascertained, measuring-device-specific, measured values and/or actuating values of the process variable and/or state variable to every other field device of the process automation system as information, and the current information of all ascertained measured values and/or actuating values of the process variables and/or state variables is available to each field device as a current process-state-vector.

Abstract: A method for predicting the remaining useful life of an engine (10) having components (18, 19, 22, 23) that are instrumented with sensors (50) that generate electronic data signals indicative of an operating condition of the component comprises identifying (52) one or more components and at least one failure mode for each component that limit an operating life of the components and engine (10). The method further comprises acquiring (62) and storing data relative to current operating conditions of the components associated with the identified failure mode; and, then determining (68) a remaining useful life of the component based on the data relative to current operating condition of the components, the data relative to historical data of the operating condition associated with the failure mode and a predicted failure mode rate.

Abstract: The present invention relates to an apparatus and a method for calculating a fatigue usage factor with respect to fatigue generated in the material of a mechanical device depending upon changes of an operation environment during operation of the mechanical device. A fatigue usage factor UOP.cyc,transient n, which is based on the operation-transient state n, is calculated by multiplying a fatigue usage factor based on a design-transient state UDSGN.cyc,transient n by the value of a characteristic fatigue usage factor F (k) as shown in the following equation: UOP.cyc,transient n=F(k)×UDSGN.

Abstract: An ultrasonic probe encircles the perimeter of a target component to be ultrasonically tested and has a base and a pair of jaws pivotally mounted to the base at opposite ends of an arcuate inner surface of the base to encircle a target component with arcuate inner surfaces of the jaws as well. The inner surfaces form a coupling fluid chamber with an outer surface of the target component. Front and rear sets of seals connected to and extending along front and rear portions of the arcuate inner surfaces seal the chamber so that it can retain a coupling fluid such as water. An arcuate set of ultrasonic transducers is connected along at least one but preferably all of the arcuate inner surfaces for transmitting ultrasonic signals to the coupling fluid chamber and into the target component.

Abstract: In a method for predicting the lifetime of a photo-semiconductor device that has a maximum light output value restricted by thermal saturation, the maximum light output value is extracted by measuring the characteristic of light output from the photo-semiconductor device with respect to drive current. The decrease tendency of the maximum output values with respect to drive time is predicted to predict the lifetime of the photo-semiconductor. Further, the predicted lifetime is updated as time passes. Therefore, in this method, even if drive condition changes, or an individual difference of the photo-semiconductor per se is present, it is possible to substantially accurately predict the lifetime of the photo-semiconductor.

Abstract: A lightning protection and detection system includes a non-conductive substrate material of an apparatus; a sensor formed of a conductive material and deposited on the non-conductive substrate material of the apparatus. The sensor includes a conductive trace formed in a continuous spiral winding starting at a first end at a center region of the sensor and ending at a second end at an outer corner region of the sensor, the first and second ends being open and unconnected. An electrical measurement system is in communication with the sensor and receives a resonant response from the sensor, to perform detection, in real-time, of lightning strike occurrences and damage therefrom to the sensor and the non-conductive substrate material.

Abstract: The present invention provides a method for obtaining material information regarding steel sheet for shipping over the entire length of the steel sheet for shipping without spending too much time and effort, providing detailed material information in large volumes to a user through a computer and network, and having the user utilize the same. Specifically, it estimates the mechanical properties of temper rolled steel sheet based on the actual rolling data in a skinpass mill installed at the exit side of the continuous annealing line or galvanization facility and provides the estimated mechanical properties through the host computer and network to the user of the steel sheet. The user can use the estimated material information so as to remove the parts defective in mechanical properties or change the press forming conditions of the steel sheet. Further, the user can feed back information to the steel sheet manufacturer.

Abstract: A method for inspecting corrosion under insulation simply and precisely at a low cost is provided. The method for inspecting CUI is characterized by obtaining signals from a fiber optical Doppler sensor attached to equipment and counting a waveform for a predetermined time before and after a point where an amplitude is over a threshold value as one acoustic emission (AE) signal, recording the AE signals and the maximum amplitudes thereof, subjecting the AE signals to a filtering process to remove noise signals, determining a frequency distribution of the AE signal hits relative to various maximum amplitude values, determining a regression line of the number of the AE hits relative to the maximum amplitudes from a scattering diagram which is obtained by double logarithmic expression of the frequency distribution, and judging existence or nonexistence of the corrosion based on a gradient of the regression line.

Abstract: The apparatus for monitoring appliances and machines having rotating components, particularly for monitoring compressors, vacuum pumps and other pumps, has a sensor, an evaluation electronics unit and an interface for the output of signals. The evaluation electronics unit has a microprocessor having three inputs for performing measurements in three different frequency ranges at different frequency resolutions, with the respective vibration intensities being averaged at a plurality of frequencies in line with the third-octave spectrum. The interface is a two-wire interface which is used to report different operating states using different DC values.

Abstract: The invention relates bridge structure safety evaluation technology by means of combining vibration measuring and structural model analysis techniques for bridge erosion evaluation and pre-warning monitoring applications. This technology can also be applied for long-term bridge structure monitoring and safety evaluation as well as judgment and evaluation of rail structure abnormality.

Abstract: The technology includes methods, a system, and a computer readable medium for predicting the time to failure of an electronic component, by generating a finite element model of the component, developing a microstructure-based failure model for each representative volume element associated with each node in the finite element model, and calculating a time to failure of the component from the shortest predicted time to failure of any node when a value of a stress variable is applied to the microstructure-based failure model of each node. The technology further includes methods, system, and a medium programmed to predict failure of a system that includes an electronic component, based on predicting time to failure of the component.

Abstract: A medical robotic system comprises a number of components that may be monitored to determine their preventive maintenance needs by recording usage-related information for the monitored components into associated non-volatile memories. When usage of the component exceeds a specified usage threshold, the system displays a warning message on its display screen to have preventive maintenance performed for the component. If the usage continues without such maintenance and exceeds a higher usage threshold, the system displays an error message on its display screen and the system transitions into an error state during which medical procedures are not allowed to be performed. The usage-related information may also be communicated to a remote computer which gathers and processes usage-related information from a number of medical robotic systems to estimate resource requirements for timely performing preventive maintenance on the medical robotic systems, and anticipated service revenues from such maintenance.

Abstract: The technology includes methods, a system, and a computer readable medium for predicting the failure of an electronic device during design of the device, by receiving data associated with the device, the data including data indicative of a device response to a specific load on the system while the device is in operation, and predicting potential failure of the device using a probabilistic model and the data, wherein the probabilistic model utilizes at least one of fast probability methods and simulation techniques.

Abstract: The present invention is a method and system for detecting an abnormal on-line analysis or laboratory measurement and for predicting an abnormal quality excursion due to an abnormal process condition.

Abstract: A system for monitoring the wear of a moving conveyor chain includes a first detector for detecting a leading end of a first link of the chain and providing a first signal corresponding thereto, a second detector for detecting a trailing end of the first link and providing a second signal corresponding thereto, and a third detector for detecting a leading end of a third link of the chain and providing a third signal corresponding thereto. The system processes the signal so as to determine a first distance D1 which is the distance between the leading end and trailing end of the first link, a second distance D2 which is the distance between the trailing end of the first link and the leading end of the third link, and a third distance D3 which is the distance between the leading end of the first link and the leading end of the third link.

Abstract: A method for determining the wear on a contact element of an electrical switch, for example, of a switching installation for high or medium voltage, includes recording electrical values which represent an electrical variable, which is relevant to an arc occurring at the switch during a switching operation, as a function of time, and calculating a wear value, which represents the wear on the contact element, from a plurality of wear contribution values. The wear contribution values are calculated from a plurality of subsets of the recorded electrical values using a plurality of wear contribution calculation rules, with the result that each of the wear contribution values is calculated from a respective one of the subsets of values according to a respective one of the wear contribution calculation rules. At least two of the wear contribution calculation rules differ from one another.