Abstract: A method for determining mass flow of a two-phase medium flowing through a measuring tube of a vortex, flow measuring device. The measuring tube has in a measuring cross section at least one bluff body for producing vortices. By sensor registering of the produced vortices, a flow velocity of the medium in the region of the measuring cross section is determined. In the method, the density of the medium in the region of the measuring cross section is determined from the specific, total enthalpy of the medium in the region of the measuring cross section, from the flow velocity of the medium in the region of the measuring cross section, from a static pressure of the medium in the region of the measuring cross section and from the static temperature of the medium in the region of the measuring cross section. Additionally, the mass flow is determined from the determined flow velocity, the determined density and a flow cross section of the medium in the region of the measuring cross section.

Abstract: A fluid flow monitoring system including one or more fluid flow dispensing valves each including a piston. Fluid flow sensors are associated with the fluid flow dispensing valves for measuring fluid flow. The fluid flow sensors include a housing with a magnet positioned therein and a piston follower is coupled to the magnet. The piston follower includes a shoulder portion positioned within the housing. A spring is operative to bias the magnet and piston follower towards the piston during operation so that piston movement is transmitted to the magnet. The housing includes a retainer portion disposed on the housing that confronts the shoulder portion of the piston follower whereby the magnet, piston follower, and spring are retained within the housing. The system also includes a fluid flow monitor that includes a microprocessor programmed to convert cycle signals from the sensors to fluid flow information.

Abstract: A conveyor mechanism conveys a powder along a path. A first camera device arranged above the conveyor mechanism detects movement of a recognizable feature on an upper surface of the powder over a period of time. A velocity of the powder can be determined based on the movement of the recognizable feature over the period of time. A device can be used to generate the recognizable feature. A first light-emitting device can illuminate the upper surface to aid detection of the recognizable feature. A second light-emitting device can project a contour line on the upper surface, and a second camera device can be used to detect a position of the contour line. A cross sectional area of the powder can be correlated based on the position of the contour line.

Abstract: A method to monitor a status from a secondary location of a plurality of equipment on a drilling site, while simultaneously enabling preventive maintenance for the plurality of equipment is described herein. A user can view at least one cycle, at least one control state, and at least one pressure. The user can also view equipment information, equipment repair history, and other information necessary to ensure that a piece of equipment has minimal down time.

Abstract: A system to monitor a status from a secondary location of a plurality of equipment on a drilling site, while simultaneously enabling preventive maintenance is described herein. A user can view at least one cycle, at least one control state, and at least one pressure. The user can also view equipment information, equipment repair history, and other information necessary to ensure that a piece of equipment has minimal down time.

Abstract: A computer assisted method to monitor a status from a secondary location of a plurality of equipment on a drilling site, while simultaneously enabling preventive maintenance is described herein. A user can view at least one cycle, at least one control state, and at least one pressure. The user can also view equipment information, equipment repair history, and other information necessary to ensure that a piece of equipment has minimal down time.

Abstract: Systems and methods for head impact injury prediction. A computer implemented method is provided for event based injury predictions. The computer implemented method receives an indication of sensor data related to an impact of a user. The received sensor data is compared to previously stored sensor data in a data store. Each instance of the previously stored sensor data is associated with a medical diagnosis. If the received sensor data matches any of the previously stored sensor data based on the comparison, then an injury risk indicator is generated based on at least one of the medical diagnosis associated with the matching previously stored sensor data or an impact history of the user. The generated indicator is presented.

Abstract: A system and method for monitoring utilization and waste of a natural resource, such as water. Data is received indicating natural resource consumption by a facility. An indication of at least one period of natural resource usage by the facility is received. Natural resource usage corresponding to utilization of the natural resource for a useful purpose. Quantities of the natural resource consumed by the facility during the at least one period of water usage is recorded as a utilized quantity.

Abstract: A velocity mapping system comprising a sensor system and an airflow mapper. The sensor system is configured to generate data about a velocity of airflow for a location in a duct system. The airflow mapper is configured to receive the data from the sensor system and generate a profile of the velocity of the airflow at the location in the duct system.

Abstract: Apparatus and methods for monitoring a hot water tank (10) of a hot water heating system, particularly with a view to minimising the energy consumed in supplying sufficient hot water. The apparatus comprises at least two tank temperature sensors (4, 5, 6) for sensing the temperature at at least two different tank heights and generating respective sensor signals in response to the sensed temperatures; a processing arrangement (22) configured to receive the tank sensor signals, determine therefrom a hot water level parameter value which is indicative of the proportion of the total volume of water in the tank which is above a predetermined temperature threshold, and output the hot water level parameter value; and an electronic memory (24) for receiving and storing the hot water level parameter value.

Abstract: Switching a transmitting and receiving direction of two transducers (2,3) in the forward and the reverse direction, a time differential memory part (17b) storing a propagation time differential every K times a unit measurement process being executed, the propagation time differential being a differential between a propagation time of the ultrasonic wave signal in a forward direction and in a reverse direction, a flow rate calculating part (15) calculating a flow rate of a passing fluid based on a lump sum of propagation times in both the forward and the reverse directions obtained at least every K times of a unit measurement process being executed, an estimating part (18) estimating a change in a momentary flow rate of the fluid based on the time differential obtained every K times of the unit measurement process being executed and storing thereof in a time differential memory part (17b), thus obtaining an accurate flow rate and detecting the change in the momentary flow rate.

Abstract: An estimation device for a cylinder intake air amount and an internal EGR rate in an internal combustion engine is provided which is capable of making an estimation with a high degree of accuracy in a small number of adaptation constants. The estimation device calculates a volumetric efficiency corresponding value and the internal EGR rate based on an exhaust efficiency (a linear function of intake pipe internal pressure) which is an index indicating an amount of residual gas which is an exhaust gas after combustion remaining in the cylinder without being discharged from the cylinder to an exhaust pipe, and an intake efficiency (a linear function of intake pipe internal pressure) which is an index indicating an amount of air coming into the cylinder from the intake pipe excluding the residual gas.

Abstract: An apparatus, a closed-loop system and method for measuring the resistance of inhalation systems and/or devices are disclosed.

Abstract: A required-circulated-refrigerant flow-rate calculating portion provided in a chilled-water flow-rate estimation calculation portion calculates an evaporator exchanged heat quantity exchanged between a refrigerant and chilled water at an evaporator based on a planned chilled-water-flow-rate value and a measured value of the temperature of the chilled water flowing in the evaporator, and calculates an evaporator-refrigerant flow rate based on that evaporator exchanged heat quantity.

Abstract: An electromagnetic flow meter includes a measurement tube, an excitation coil, an excitation current supplying unit supplying an excitation current with an excitation frequency fex to the excitation coil, a pair of electrodes disposed inside the measurement tube, a measuring unit measuring a flow based on an emf that arises between the electrodes, a first A/D converting unit that converts the emf to a digital signal, a sampling unit sampling the digital signal, a noise evaluation value calculating unit, based on at least the sample data sampled by the sampling unit, calculating as a noise evaluation value the magnitude of the impact of a noise component owing to adherence of foreign matter to the electrodes upon the measurement of the flow, and an electrode scaling diagnosing unit determining an electrode foreign matter adherence state by comparing the noise evaluation value and a predetermined diagnostic threshold value.

Abstract: A monitoring system for a beverage dispensing system having at least one fluid conduit. The monitoring system includes at least one monitoring apparatus configured to be coupled to at least one fluid conduit, each monitoring apparatus having at least one sensor and being configured to determine when liquid is flowing through the conduit, at least one hub configured to receive information from the at least one monitoring apparatus about when liquid is flowing through the at least one conduit, and at least one processor configured to determine a volume of liquid flowing through the fluid conduit based on the information received from the at least one monitoring apparatus.

Abstract: A system, method, and computer readable medium for calculating well flow rates produced with electrical submersible pumps using measured voltage, current, frequency and pressure data. An efficiency to flow rate ratio is calculated from the voltage, current, and pressure data. The efficiency to flow rate ratio is used to obtain a non-dimensional flow rate. The flow rate through the electrical submersible pump is calculated from the non-dimensional flow rate.

Abstract: An air flow measurement apparatus includes an air flow sensor for outputting an air flow signal indicative of detected air flow, a reference voltage generator for outputting reference voltage signals, a multiplexer for sequentially selecting the signals in a predetermined order, an A/D converter for converting the signals into digital data in an order selected by the multiplexer, and a signal processing unit for applying correction processing to air flow voltage data corresponding to the air flow signal using reference voltage data corresponding to the reference voltage signals. The signal processing unit has a sampling timing setting section for determining sampling timings at which the A/D converter samples the signals in such a manner that the sampling timing at which the air flow signal is sampled is interposed between the sampling timings at which successive two of the reference voltage signals are sampled.

Abstract: A method of providing a flow control device is disclosed, which one aspect may include: defining a flow rate; defining a desired relationship between a parameter of the flow control device that exhibits a substantial change when a selected property of the fluid changes in a first range and remains substantially constant when the selected property is in the second range; determining using a computer and a simulation program the relationship between the performance parameter and the selected property over the first range and the second range for the defined flow rate for a geometry of a flow through area of a flow control device; comparing the determined relationship of the performance parameter with the desired relationship; altering the geometry to a new geometry when the difference between the desired performance and the determined performance is outside a desired range; determining using the computer and the simulation program the relationship between the performance parameter and the selected property over

Abstract: Techniques for airflow analysis are provided. In one aspect, a mobile sensing device is provided. The mobile sensing device includes an airflow sensing system having a plurality of airflow sensing units arranged in a grid. Each airflow sensing unit includes a first air passage that contains at least one first airflow sensor; a second air passage perpendicular to the first air passage, wherein the second air passage contains at least one second airflow sensor; and a third air passage perpendicular to the first air passage and the second air passage, wherein the third air passage contains at least one third airflow sensor.

Abstract: Object of the present invention is to measure the quantity of a gas flowing through a gas meter and accurately calculate, on a per-appliance basis, the quantity of used gas in each time during which a gas appliance connected to a downstream point is used, without involvement of a waveform pattern. A flow rate measuring apparatus (10) has a flow rate measurement unit that measures a flow rate at given time intervals; an appliance determination unit that calculates a flow difference between flow rates acquired at two arbitrary times by measuring the use of an appliance connected to a downstream point with reference to the flow rate measurement unit, thereby determining an operating appliance; and an appliance flow rate calculation unit that calculates the appliance-specific usage flow rate by switching a calculation method according to the number, types, combinations, and priority levels of currently-operating gas appliances that are results of determination made by the appliance determination unit.

Abstract: Usage of a utility in a multi-unit building is apportioned to a single unit by measuring the total usage of the utility using a meter unit to produce a total usage measurement, then positioning at least one sensor unit in a single unit of the multi-unit building and monitoring usage of the utility by the single unit using the at least one sensor unit to produce monitoring data. Then a processor unit receives the total usage measurement and the monitoring data and correlates them to generate correlated data. Finally, the processor unit apportions the total usage measurement to the single unit based on the correlated data.

Abstract: A system for determining a real time solid flow rate of a solid-gas mixture is provided. The system includes multiple sensors, a data-fusion unit and an estimating unit. The sensors generate multiple measurement signals for obtaining at least two measured values of the real time solid flow rate. The data-fusion unit receives the measured values and establishes a state-space model based on the measured values. The estimating unit estimates the state-space model to generate an estimated value of the real time solid flow rate. A method for determining a real time solid flow rate of a solid-gas mixture is also presented.

Abstract: A system for measuring real time efficiency/performance of at least one pump in a plant or other facility includes a plurality of monitoring devices disposed in relation to said at least one pump to measure power usage, pump speed and flow characteristics of the at least one pump. A processing system is configured to receive input signals from the sensors in which the efficiency of the at least one pump can be calculated based on the sensor inputs in real-time. The processing system can also compare the calculated pump efficiency values with a user defined set point or threshold or compare to the expected pump performance.

Abstract: A mass flow controller (MFC), a method for calibrating an MFC, and a method for operating an MFC are disclosed. The method for calibrating the MFC includes obtaining data relative to two signals from a thermal mass flow sensor when operating the mass flow controller at different flow rates with a calibration gas, and storing the data relating to the two signals in connection with corresponding flow-rate values. The method for operating the MFC includes obtaining data relative to the two signals from the thermal mass flow controller and accessing the calibration data to determine an unknown flow rate for a process gas that may be the same gas as the calibration gas or may be another gas that is different from the calibration gas.

Abstract: A machine diagnosing device includes a drive object driving force estimating unit for estimating drive object driving force based on a torque command value toward a servo motor which is acquired using a position command value, an elastic deformation error estimating unit for estimating an elastic deformation error of a ball screw with the drive object driving force, and a positional deviation calculating unit for calculating a positional deviation using a rotation position of the servo motor and the position of a table, and a machine damage diagnosing unit for diagnosing a machine damage by calculating a machine damage coefficient using the elastic deformation error and the positional deviation, comparing the obtained machine damage coefficient with a previously set threshold value, and diagnosing a damage state of the drive object.

Abstract: An impact sensor is located in a distribution tower which divides the seed and/or nutrient flow into individual rows, and a second sensor provides a compensation signal dependent upon one or more variables such as the velocity of the air in the conveying system, implement vibrations. As the seed/fertilizer bounces off of the impact sensor and flows into the individual row air streams, the impact sensor provides a force signal to a processor which calculates the total particulate mass flow rate from the force signal and the air velocity signal. To determine individual seed and fertilizer rates, a rate controller temporarily changes the metering rate of one of the materials, and the processor then calculates the desired information from the mass flow change and meter speed change. Another embodiment includes seed sensor structure at the meter output for achieving or confirming accuracy.

Abstract: The present invention relates to a system, method, and computer program product for determining the flow rate of a fluid. The system, method, and computer program product generate a thermal sensor based mass flow rate for the fluid, where the thermal sensor based mass flow rate is determined at least in part from the thermal sensor signal (36). The system, method, and computer program product generate a pressure sensor based mass flow rate for the fluid, wherein the pressure sensor based mass flow rate is determined at least in part from the pressure sensor signal (51a). The system, method, and computer program product generate at least one calibration factor (?) using the thermal sensor based mass flow rate and the pressure sensor based mass flow rate. The system, method, and computer program product may generate a calibrated pressure sensor based mass flow rate by using the at least one calibration factor (?) to modify the pressure sensor based mass flow rate.

Abstract: An apparatus and method for determining the volume of hot water dispensed during a given timeframe from a hydrocarbon fueled water heater based on the volume of fuel consumed by the water heater during the timeframe and the average temperature difference between the inlet water temperature and the outlet water temperature during the timeframe.

Abstract: A meter controller comprises a first input, a second input, and a processor. The processor is configured to receive first and second volumetric flow measurements and to calculate a quasi fluid density value required to cause the first volumetric flow measurement to equal the second volumetric flow measurement. The processor is further configured to subtract a first fluid density value from the quasi fluid density value for calculating a density correction factor. The density correction factor is subtracted from the first fluid density value to calculate a corrected second density value. The corrected second density value is applied to at least one of the first volumetric flow measurement and the second volumetric flow measurement for calculating a mass flow rate measurement.

Abstract: A sensing system and method for use with a gas filter in a gas conduit attached to a gas blower, having a motor for producing a first gas flow blower speed, discards readings taken when the blower is off or during blower startup and shutdown, and recalculates a clog threshold in response to changes in the fan speed of a multi-speed blower.

Abstract: The calculating device has first and second Fourier transform portions performing Fourier transforms on two respective inputted signals; a complex conjugate deriving portion deriving a complex conjugate of a value outputted from the first Fourier transform portion; a multiplier multiplying the complex conjugate with the value outputted from the second Fourier transform portion, and outputting the value after the multiplication; a Hilbert transform portion performing a Hilbert transform on the value after multiplication; first and second inverse Fourier transform portions performing respective inverse Fourier transforms on the value after multiplication and the value outputted from the Hilbert transform portion; a phase relationship deriving portion deriving a phase relationship between the two inputted signals based on the values outputted from the first and second inverse Fourier transform portions; and a time difference deriving portion deriving a time difference between the two inputted signals based on th

Abstract: An improved method and computer system is provided, for analyzing the two- or three-dimensional movement of a fluid in an absorbent article that comprises fluid-swellable composite material, which comprises a fluid-swellable solid material, and that comprises void spaces in the fluid-swellable composite material, the fluid-swellable composite material being defined by a virtual two-dimensional or three-dimensional mesh, to determine the performance or property of at least one feature of the fluid-swellable composite material thereof, or the absorbent article, the method comprising: inputting one or more properties for the fluid-swellable (composite) material into a model and evaluating this to determine the performance of a feature of the absorbent article or fluid-swellable composite material thereof, the virtual model.

Abstract: Methods to detect when a human body contacts a predetermined portion of a machine are disclosed. The methods distinguish contact with a person from contact with other materials. The methods are particularly applicable in woodworking equipment such as power saws to detect contact between a person and the blade of the saw. Woodworking machines and memory devices for use in woodworking machines having safety systems designed to detect a dangerous condition between a human and a dangerous portion of the woodworking machine and to trigger some action to mitigate the dangerous condition are also disclosed.

Abstract: A processing apparatus includes a processing chamber, gas supply paths provided in a corresponding relationship with the kinds of process gases supplied into the processing chamber, and valves respectively arranged in the gas supply paths. The apparatus further includes a measuring unit for measuring a physical parameter associated with each of the process gases passing through the gas supply paths, a register unit which stores the physical parameter, and a control unit configured to determine a process status based on the physical parameter stored in the register unit. The register unit is provided in a lower-hierarchy control device connected to the control unit of a higher hierarchy to transmit and receive signals to and from the control unit. The lower-hierarchy control device is configured to control input and output signals between the control unit and end devices under the control of the control unit.

Abstract: A flow meter device is coupled to at least one sensor that measures a flow speed and provides status signals from which the flow speed can be determined. The flow meter receives and processes the flow measurement data provided by the at least one sensor. The at least one sensor is enabled at defined time instances for a defined interval time. The flow meter receives at least one status signal from the sensor each time the sensor is enabled and processes the status signals to generate a trigger event when certain conditions arise. A processing unit wakes up from a sleep mode when a trigger event is generated by the flow meter device.

Abstract: One embodiment involves detecting the fouling of an air filter used to filter airflow entering a computer system. An expected airflow rate is obtained from a current fan speed. An expected temperature rise between two positions is computed as a function of the expected airflow rate and the power consumption of heat-generating components, such as servers. An actual temperature rise is obtained from temperature sensors. An electronic alert is automatically generated in response to the actual temperature rise exceeding the expected temperature rise by a setpoint. Different setpoints may be used to trigger distinct electronic alerts.

Abstract: A system, a device and a method are for retrieval of measured values, items of diagnostic information or device parameters in level measurement, pressure measurement, flow measurement or limit detection. Provided in the measuring device is a flag which is raised when the measuring device changes a measuring device parameter, for example. An external control device receives this flag and, using said flag, can determine whether a device parameter has been changed in the measuring device. If this is the case, it requests the group of device parameters, associated with this device parameter, from the measuring device. In this manner, the transfer of data can be reduced.

Abstract: A fluid flow meter estimates the velocity of water or another fluid flowing through pipe by comparing measurements of the water velocity to one or more pre-determined templates. The fluid flow meter may collect measurement signals from one or more flow sensors (e.g., ultrasonic transducers), estimate the fluid velocity or flow rate by comparing the measurement signals to the template(s), and either store the comparison results in local memory, transmit the results to a remote memory or server, or both. In some embodiments, the fluid flow meter transmits the results to a server via a wireless interface (e.g., a Zigbee, Bluetooth, or Wi-fi interface). The transducers and processing system can be powered by a battery, a power line, or, for manifolds installed outdoors, a solar cell. Example transducers and processing systems may also have a passive wake-up feature for power reduction; that is, they may only draw power when water or another fluid flows through the pipe.

Abstract: Startup and operational techniques for a digital flowmeter are described. For example, during a startup operation of the flowmeter, the mode of operation might include a random sequence mode, in which filtered, random frequencies are applied as a drive signal to a flowtube associated with the digital flowmeter. Once the flowtube reaches a resonant mode of vibration, the digital flowmeter may transition to a positive feedback mode, in which a sensor signal representing a motion of the flowtube is fed back to the flowtube as a drive signal. In a digital synthesis mode of operation, the analyzed sensor signals are used to synthesize the drive signal. The digital flowmeter may revert to a previous mode to regain stable and desired oscillation of the flowtube, such as might be required during a recovery operation associated with a disturbance to an operation of the digital flowmeter.

Abstract: A method for the deployment and retrieval of data loggers, which are deployed in a first step at separate locations on a supply network having numerous branching pipelines, e.g. for drinking water, which record, in a second step, at least the flow sounds of the medium flowing at the deployed locations, and which, in a third step, are read out by a vehicle driving past, having a readout device disposed therein, wherein the reading device is allocated a GPS module, and that when the data loggers are deployed at the locations assigned to them on the pipeline, the current GPS locations of the data loggers at said locations are stored in the readout device.

Abstract: A method for determining permeability of a reservoir using a packer-probe formation testing tool. The elements of the method include generating, using a dual packer tool module, fluid flows from the reservoir into a wellbore, obtaining pressure data associated with the fluid flows using an observation probe tool module, wherein the packer-probe formation testing tool comprises the dual packer module and the observation probe tool module, identifying a portion of the pressure data corresponding to a spherical flow regime, determining horizontal permeability based on the portion of the pressure data, and displaying an output generated using the horizontal permeability.

Abstract: Motion is induced in a conduit that contains a fluid. The motion is induced such that the conduit oscillates in a first mode of vibration and a second mode of vibration. The first mode of vibration has a corresponding first frequency of vibration and the second mode of vibration has a corresponding second frequency of vibration. At least one of the first frequency of vibration or the second frequency of vibration is determined. A phase difference between the motion of the conduit at a first point of the conduit and the motion of the conduit at a second point of the conduit is determined. A quantity based on the phase difference and the determined frequency is determined. The quantity includes a ratio between the first frequency during a zero-flow condition and the second frequency during the zero-flow condition. A property of the fluid is determined based on the quantity.

Abstract: A simple, passive and rugged device for measuring the flow rate of liquid. A variable area obstruction valve, a differential pressure sensor and a densitometer are combined in a single housing to provide for a highly accurate and precise measure of mass flow.

Abstract: Methods, systems, and apparatuses are disclosed for a measuring the velocity of a fluid.

Abstract: A mobile-object information acquiring apparatus (100) acquires the state of a mobile object. A current-information acquiring unit (101) acquires energy consumption (actual energy consumption) accompanying travel of the mobile object. As setting unit (102) sets for each factor causing energy consumption of the mobile object to change, information related to the mobile object affected by the factor. An estimating unit (103), based on information that is related to the mobile object and for a reference point in time, estimates energy consumption (reference energy consumption) consequent to the travel of the mobile object. A calculating unit (104) calculates for each factor, the amount of change of the actual energy consumption with respect to the reference energy consumption.

Abstract: Drive techniques for a digital flowmeter are described. The drive techniques account for delays caused during digital signal processing of sensor signals that correspond to a motion of a flowtube, as well as drive signals that impart motion to the flowtube. Such delays may be caused by a variety of factors, including delays associated with analog/digital conversion of the signals and/or filtering of the signals. The techniques include open-loop techniques and closed-loop techniques, which can be used separately or together during the start-up and operation of the digital flowmeter.

Abstract: In a cooling section having a plurality of coolant outlets, the coolant outlets are supplied with the coolant via transmission lines and a mutual main line. Individually opening and closing valves are disposed in the transmission lines. An automation device of the cooling section opens and closes the valves at valve-specific opening and closing times during the normal operation of the cooling section in order to apply coolant to the rolling stock according to a quantitative target coolant course. During the determination of the opening times, the automation device considers a respective valve-specific characteristic. In calibration operation of the cooling section, the respective characteristic is initially determined at least for some of the valves by opening and closing the respective valve, and detecting the chronological course of the quantitative coolant flow effected thereby by a measuring arrangement disposed in the main line.

Abstract: A compensation device for fluidic oscillation flow meters is provided. The compensation device includes a fluid supply unit, a fluidic oscillator, an electronic valve, a reference tank and a computer. The fluid supply unit supplies fluid into a pipe. The fluidic oscillator generates a characteristic oscillation frequency when the fluid supplied from the fluid supply unit passes through the fluidic oscillator. The electronic valve controls a flow rate of the fluid passing through the fluidic oscillator. The reference tank accumulates and stores the fluid passing through the electronic valve. The computer calculates a characteristic linear compensation coefficient using data about the time for which the fluid had passed through the fluidic oscillator, an oscillation frequency of the fluidic oscillator, a preset flow rate of the electronic valve, and a preset fluid accumulation amount of the reference tank. The computer stores the calculated characteristic linear compensation coefficient.

Abstract: A fan of a computing system is associated with a performance characteristic. It may be determined whether a component associated with the computing system is installed based on the performance characteristic.