Abstract: The invention relates to improvements in compressors and, in particular, to an improvement in a method of controlling variable speed dynamic compressors to avoid ‘motor overload as a result of choking.1 The invention therefore comprises a method of controlling a compressor to provide compressed gas at a target delivery pressure (Pt) and prevent excessive motor power consumption, the compressor being driven by a variable speed motor which has motor windings, wherein the gas inlet temperature (Tin), gas output delivery pressure (Pd), motor speed (Vm) and the motor winding temperature (Tmw) are continuously measured during operation of the compressor. The gas inlet temperature (Tin) is used to determine a predetermined maximum motor winding temperature (Tmwmax) limit. The maximum motor winding temperature (Tmwmax) is used (to set a maximum motor speed (Vmmax) limit.

Abstract: In a field device for process automation, a reprogammable logic device is used, in order to achieve a high flexibility as regards hardware components.

Abstract: A motor control apparatus includes a sub-controller including a two-degree-of-freedom repetitive compensator and a shaping filter. The two-degree-of-freedom repetitive compensator includes a forward delay placed in a forward route of a loop and a feedback delay placed in a feedback route thereof and is configured so that a total delay time provided by the forward delay and the feedback delay is equal to the cycle of a target command or a disturbance. The shaping filter is configured so that the product of the pulse transfer function of the two-degree-of-freedom repetitive compensator and the complementary sensitivity function of a general-purpose control system has a low-pass characteristic.

Abstract: Enables minimization of steady-state objective function P(z?), subject to a set of constraints zmin?z??zmax, and under the assumption that the values of the state vector, z, at different points in time related via a model expressed in dynamic open equation format Q(z?, zk, zk-1, zk-2, . . . , zk-n)=0, where z? is predicted final value of state vector, z, and zk, zk-1, zk-2, . . . , zk-n are current and previous values of state vector, z. Determines optimum operation of an industrial process having steady-state objective function P(z?), including: receiving outputs from the process; minimizing steady-state objective function P(z?) subject to set of constraints zmin?z??zmax; wherein values of state vector at different times are related via model of form Q(z?, zk, zk-1, zk-2, . . . , zk-n)=0; to minimize objective function P(z?). Industrial process to be optimised may include measured and unmeasured process variables.

Abstract: A computer-based method and system for pervasive model adaptation are provided. The method includes providing a production plan to a production system, executing the production plan in the production system, collecting observation data produced by at least one sensor in the production system during execution of the production plan into computer memory, calculating changes to be made to a system model in the computer memory based on the collected observation data, dynamically updating the system model according to the calculated changes, creating an updated production plan based at least partially on the dynamically updated system model, and storing the updated production plan within the computer memory.

Abstract: A method, system, and computer program product for optimizing power consumption of an executing processor executing. The method includes determining a first sensitivity relationship (SR) based on a first and a second performance metric value (PMV) measured at a first and second operating frequency (OF), respectively. The first SR predicts workload performance over a range of OFs. A third OF is determined based on the first SR and a specified workload performance floor. A third PMV is measured by executing the processor operating at the third OF. A second SR based on the second and third PMVs is then determined. The first and second SRs are logically combined to generate a third SR. Based on the third SR, a fourth OF is outputted.

Abstract: A power circuit protection and control device simulator emulates in real time identical circuit protection and control functions performed by the actual device being simulated and generates real time simulated operational information concerning at least one of the device or the power circuit. A human-machine interface, such as through a web browser, allows a user to input power circuit operational parameters, such as motor current and load, and device variable circuit protection and control operational parameters, such as trip class, ground fault detection or phase unbalance protection. The simulator displays in real time simulated operational information on the human-machine interface. The simulator may be used to simulate operation of an electronic overload relay and an electric motor controlled by the relay.

Abstract: A thermal error compensation method for machine tools is disclosed, which comprises the steps of: disposing at least a thermal sensor at positions neighboring to the at least one heat source of a machine tool; driving the machine tool to operate under a specific operation condition for enabling the at least one heat source to generate heat; generating a thermal signal according to the temperature detected by the at least one thermal sensor; using a heat conducting calculation unit to access the thermal signal and the information relating to the specific operation condition to be used in a calculation for obtaining and thus outputting at least a node temperature; and using an error compensation unit to access the at least one node temperature to be used in a calculation for obtaining thermal error compensation values for the machine tool.

Abstract: A method for determining gain of a back-electromotive force amplifier may include setting an electric motor into a tri-state function mode and storing a first quasi steady-state value for back-electromotive force from the difference signal, and forcing a reference current through the electric motor and determining a first value of the gain of the amplifier for equaling a difference signal to the first quasi steady-state value. The method may further include setting the electric motor into a tri-state function mode a second time and storing a second quasi steady-state value for back-electromotive force from the difference signal, and increasing the first value of the gain by an amount proportional to a difference between the second quasi steady-state value and the first quasi steady-state value.

Abstract: The systems and methods described herein allow for automatic identification experiments in a closed loop, where the old control strategy, already tuned and tested, is utilized. The strategy is modified to inject additional signal optimized for identification. The experimenting time may be reduced by performing only those system manipulations which explore model uncertainties important to potential degradation of controller performance by discrepancy between the system and the model. The disruptions are reduced by keeping the control loop closed, which eliminates waiting for steady state before applying steps to the inputs and reduces the risk of process limits crossing. The energy of additional signal can be set to meet the maximum allowable disruption requirements. The energy of additional signal is in a direct relation to the speed of identification related information gathering. It can be varied in time to follow the needs of system operators.

Abstract: A recommendation engine coupled to a server computer in communication with a plurality of hosts is described. The recommendation engine includes computer readable intrusion-protection instructions stored in a memory device, which cause a processor of said server computer to determine a current host-protection configuration for a target host; detect discrepancy between said current host-protection configuration and a prior host-protection configuration; install said current host-protection configuration in said target host upon detecting said discrepancy; record successive host-reconfiguration periods, a host reconfiguration period being a difference between successive instants of time at which a current host-protection configuration differs from a prior host-protection configuration; determine a monitoring period according to a value of at least one of said successive host-reconfiguration periods; and a scheduler for activating said intrusion-protection instructions according to said monitoring period.

Abstract: A control strategy for heating, ventilating, and air-conditioning (HVAC) units used to condition the environment in data centers and other commercial buildings such as retail stores with an open-plan design is provided to coordinate the operation of the actuators of the HVAC units. A supervisory controller receives feedback signals from a plurality of environmental sensors and uses a set of references values to determine control signals to the actuators of the HVAC units. A pseudoinverse of a transfer function matrix G may be used to determine the control signals from errors in the feedback signals relative to the reference signals.

Abstract: Systems and methods for determining active constraints in a surface facility network, which include the use of slack variables and multipliers in system equations to eliminate the extraneous (inactive) constraints.

Abstract: The present invention presents two new model types and a new method for evaluating a model used in the control application. These include a compound model, a hybrid model and a directional change coefficient model. The present invention allows the mixing of models with different inputs and outputs and the switching between these models based criteria for measuring optimization accuracy. The present invention allows switching between these models. The compound model is a model type that allows zooming in on the process to model parts of the data space with higher fidelity or resolution without loosing the capability to model the complete data space. The modeler does not loose any functionally over a regular neural network, but instead gains the ability to define the conditions when the model should use network weights best matched to the defined local conditions. The hybrid model is an extended version of a compound model.

Abstract: A method and system of determining tuning parameters for use in tuning a controller used in a process control loop for a motor and associated load. The method includes providing tuning parameters, applying an excitation test signal, receiving frequency response data to determine phase and gain margins, creating an instability region defined by a bounded area that connects the phase and gain margins with a boundary on a gain vs. phase plot, assigning and applying cost functions, and computing stability determinations.

Abstract: Various embodiments of the invention are directed to methods and systems for assigning credit to the external and intermediate inputs of an enterprise-level system or other aggregate process with one or more global outputs that is composed of a number of interconnected local processes. Assigning credit is a mechanism for evaluating the impact of a particular variable, e.g., an input to one of the local processes, on the final output of the aggregate process. In certain embodiments of the invention, credit is assigned to the local inputs of each local process in two steps. First, for each local input, a local credit assignment is obtained. For chained outputs, credit assignment data is provided as calculated for the later stage processes to which the outputs are chained. Second, a global credit assignment is derived for the local inputs from the local credit assignment and the credit assignment information from later stage processes.

Abstract: A system includes a first controller configured to monitor processes associated with a process facility and to generate control data for optimizing the process facility. The system also includes a second controller configured to use stochastic calculus of variations calculations to modify at least a portion of the control data. The second controller is configured to provide discrete supply chain control and optimization for the process facility and to track at least one of demand requirements and shipping requirements for product manufactured by a discrete supply chain manufacturing process. The system further includes third controllers configured to operate in accordance with the control data to control the processes and to optimize the process facility.

Abstract: A plant monitoring and control apparatus having a function to simulate an object to be monitored and controlled for verifying healthiness of a control processing unit is provided with an input separating operation unit and an output separating operation unit which separate DI data and DO data handled by the control processing unit by transforming the DI data and the DO data into a label format differing from a label format of PDI data and PDO data which are related to input and output between the object to be monitored and controlled and the plant monitoring and control apparatus. In test mode, a switching unit switches an input device of the control processing unit and an output device thereof to a simulator unit provided within the plant monitoring and control apparatus.

Abstract: A method solves a quadratic programming (QP) problem in real-time implementations of model predictive control for automation applications. The method can be implemented for fine-grained parallel solutions. Due to the extreme simplicity of the method, even serial implementations offer considerable speed advantages. The method solves the problem by formulating, over a predetermined time interval, an optimization problem with a quadratic cost function, and linear state and control constraints as a quadratic program for the application. Then, the quadratic program is solved by applying a parallel quadratic programming update law starting from a positive initial estimate to obtain control actions for the application.

Abstract: An extremum seeking control method optimizes a control process for a plant such as an air handling unit. The method compensates for abrupt changes in the operation of the plant by resetting the extremum seeking control strategy in response to a detection of the abrupt change.

Abstract: A braking control method that includes: (1) regularly updating a grip model representative of a relationship between a coefficient of friction and a wheel slip rate; (2) determining, with an iterative calculation process including a plurality of calculation cycles a variation of a braking setpoint in a given prediction horizon, the variation of the braking setpoint in the given prediction horizon being established using the regularly updated grip model and its characteristic shape and so that the variation of the braking setpoint in the given prediction horizon complies with the braking order and complies with a given calculation constraint which is function of the wheel slip rate; and (3) retaining as the generated braking setpoint a value of the braking setpoint in the given prediction horizon which corresponds to a first calculation cycle of the plurality of calculation cycles of the iterative calculation process.

Abstract: The method for generating an integrated guidance law for aerodynamic missiles uses a strength Pareto evolutionary algorithm (SPEA)-based approach for generating an integrated fuzzy guidance law, which includes three separate fuzzy controllers. Each of these fuzzy controllers is activated in a unique region of missile interception. The distribution of membership functions and the associated rules are obtained by solving a nonlinear constrained multi-objective optimization problem in which final time, energy consumption, and miss distance are treated as competing objectives. A Tabu search is utilized to build a library of initial feasible solutions for the multi-objective optimization algorithm. Additionally, a hierarchical clustering technique is utilized to provide the decision maker with a representative and manageable Pareto-optimal set without destroying the characteristics of the trade-off front. A fuzzy-based system is employed to extract the best compromise solution over the trade-off curve.

Abstract: An apparatus and method for restricting operation of a power delivery system are disclosed. In at least some embodiments, the apparatus includes a first input terminal at which is received a first command signal, and a second input terminal at which is received an additional signal. The apparatus further includes an output terminal at which is provided a control signal, and a circuit that generates the control signal based at least indirectly upon the first command and additional signals. The control signal generated by the circuit is configured to cause the power delivery system to not deliver at least one type of power when the first command signal indicates a command to do so, if the additional signal indicates an acceptability status. In some embodiments, the power delivery system is an isolation system (e.g., safety isolation system) as are employed in industrial environments, and the apparatus is a permissive module.

Abstract: The control optimization method for helicopters carrying suspended loads during hover flight utilizes a controller based on time-delayed feedback of the load swing angles. The controller outputs include additional displacements, which are added to the helicopter trajectory in the longitudinal and lateral directions. This simple implementation requires only a small modification to the software of the helicopter position controller. Moreover, the implementation of this controller does not need rates of the swing angles. The parameters of the controllers are optimized using the method of particle swarms by minimizing an index that is a function of the history of the load swing. Simulation results show the effectiveness of the controller in suppressing the swing of the slung load while stabilizing the helicopter.

Abstract: A method of performing oilfield operations for an oilfield having a subterranean formation with a reservoir therein is provided. The method involves generating a business analysis of the oilfield based on business inputs, generating an operational analysis of the oilfield based on operational inputs, and selectively integrating the business analysis with the operational analysis by using the operational outputs as at least a portion of the business inputs and by using the business outputs as at least a portion of the operational inputs to form an integrated oilfield analysis. The business analysis includes business outputs for characterizing the business impact of projects performed on the oilfield. The operational analysis includes operational outputs for characterizing the operational impact of projects performed on the oilfield. The integrated oilfield analysis includes integrated oilfield outputs for characterizing the business and operational impact of projects performed on the oilfield.

Abstract: A controlling device that includes a model that predicts the value of a measured signal obtained when an operation signal is given to a thermal power generation plant, a function that learns a method of generating a model input such that a model output satisfies the plant value, a function that determines an operation signal to be given to the plant according to the learning result, a database that stores measured signal limit values set in advance, an external input interface that fetches measured signals from the plant, a measured signal database that stores the values of the fetched measured signals, and a function that determines an initial value of the plant model output value by using limit values of the measured signals and at least one of an average value, a maximum value, and a minimum value that are calculated from the measured signals stored in a measured signal database.

Abstract: Method and apparatus is disclosed which allocates the execution of a commanded vehicle maneuver among the vehicle's control effectors capable of affecting such maneuver, with consideration given to the possible nonlinear and/or non-monotonic effects each control effector's displacement may have on the vehicle and on each other's performance.

Abstract: The fuzzy logic-based control method for helicopters carrying suspended loads utilizes a controller based on fuzzy logic membership distributions of sets of load swing angles. The anti-swing controller is fuzzy-based and has controller outputs that include additional displacements added to the helicopter trajectory in the longitudinal and lateral directions. This simple implementation requires only a small modification to the software of the helicopter position controller. The membership functions govern control parameters that are optimized using a particle swarm algorithm. The rules of the anti-swing controller are derived to mimic the performance of a time-delayed feedback controller. A tracking controller stabilizes the helicopter and tracks the trajectory generated by the anti-swing controller.

Abstract: An MPC adaptation and tuning technique integrates feedback control performance better than methods commonly used today in MPC type controllers, resulting in an MPC adaptation/tuning technique that performs better than traditional MPC techniques in the presence of process model mismatch. The MPC controller performance is enhanced by adding a controller adaptation/tuning unit to an MPC controller, which adaptation/tuning unit implements an optimization routine to determine the best or most optimal set of controller design and/or tuning parameters to use within the MPC controller during on-line process control in the presence of a specific amount of model mismatch or a range of model mismatch.

Abstract: Methods and systems for controlling drilling operations include using a statistical model to identify at least one controllable drilling parameter having significant correlation to an objective function incorporating two or more drilling performance measurements. The methods and systems further generate operational recommendations for at least one controllable drilling parameter based at least in part on the statistical model. The operational recommendations are selected to optimize the objective function.

Abstract: A control apparatus capable of improving the control accuracy and stability when controlling a controlled object with a predetermined restraint condition between a plurality of model parameters, or a controlled object having a lag characteristic, using a control target model of a discrete-time system. The control apparatus has an ECU which arranges a control target model including two model parameters such that terms not multiplied by the model parameters and terms multiplied by the same are on different sides of the model, respectively. Assuming the different sides represent a combined signal value and an estimated combined signal value, respectively, the ECU calculates onboard identified values of the model parameters such that an identification error between the signal values is minimized, and calculates an air-fuel ratio correction coefficient using the identified values and a control algorithm derived from the control target model.

Abstract: A method includes receiving information associated with a level of material in a tank, where the tank has a hatch. The method also includes determining whether the level of material in the tank experiences a specified variation within a critical zone associated with the hatch. The specified variation is indicative of the hatch being open while the tank is being filled. In addition, the method includes generating an alarm when the level of material in the tank experiences the specified variation. Determining whether the level of material in the tank experiences the specified variation could be based on an entrance level speed of the material, which identifies a rate at which the level of material in the tank is increasing when the material level crosses a lower bound of the critical zone. Also, no alarms could be generated when the level of material in the tank is outside the critical zone.

Abstract: A multivariable model predictive controller (MPC) for controlling a coalbed methane (CBM) production process. The MPC includes input ports for receiving a plurality of measurement signals including measured process parameters from CBM wells in a well field. A control loop includes a mathematical model that controls the CBM gas production. The model includes individual production characteristics for each CBM well that predicts its behavior for controlled variables (CVs) with respect to changes in manipulated variables (MVs) and disturbance variables (DVs). The control loop calculates future set points for the MVs based on the model and the measured process parameters for CBM production to achieve at least one control objective for the well field. A plurality of output ports provide control signals for implementing the future set points which when coupled to physical process equipment at the plurality of CBM wells control the physical equipment to reach the future set points.

Abstract: A method of offline code validation and a process control system are provided. The system includes a plurality of sensors each configured to generate a sensor output value representative of a respective sensed parameter in a process plant, at least one process controller configured to receive one or more of the sensor output values and to generate a controller output value using the one or more of the sensor output values and a control algorithm associated with the at least one process controller, a plurality of controlled components configured to receive an associated controller output value, and an offline computing environment including a selectable model controller configurable to represent the at least one process controller, the model controller selectable by a user from code representing the at least one process controller and displayed on a user interface.

Abstract: The subject mater herein relates to coal mills and, more particularly, inferential pulverized fuel flow sensing and manipulation within a coal mill. Various embodiments provide systems, methods, and software to manipulate a primary air flow rate and a coal feed rate into a coal mill to produce a target pulverized fuel flow. Some embodiments include sensing a differential pressure between two or more locations within a coal mill to estimate a recirculated load of coal at one or more stages within the coal mill.

Abstract: A control systems and methods are presented for controlling a production system, in which a model-based planner includes a formulation, such as a SAT formulation representing possible actions in the production, with a solver being used to provide a solution to the formulation based at least partially on production and diagnostic goals and the current plant condition, and a translation component translates the solution into a plan for execution in the plant.

Abstract: A system facilitates detecting an abnormal operation associated with a level regulatory control loop in a process plant. A model for modeling at least a portion of the level regulatory control loop may be utilized with respect to first and second signals associated with regulatory control of a level of material in a tank. The model may include a first regression model in a first range corresponding to a first operating region of the level regulatory control loop. The model may be capable of being subsequently configured to include at least a second regression model in at least a second respective range corresponding to at least a second respective operating region different than the first operating region. The model may generate a prediction of the second signal as a function of first signal. It may be determined whether the second signal significantly deviates from the prediction of the second signal generated by the model.

Abstract: A method to enable wafer result prediction from a batch processing tool, includes collecting manufacturing data from a batch of wafers processed in batch in the batch processing tool, to form a batch processing result; defining a degree of freedom of the batch processing result based on the manufacturing data; and performing an optimal curve fitting by trial and error for an optimal function model of the batch processing result based on the batch processing result.

Abstract: The present invention is a method for synchronizing multiple layers of constrained optimization with both layers having some common variables in a to processing plant. The layers of optimization can include Planning, Scheduling, Real-Time Optimization and Model Predictive Control.

Abstract: A method of modeling a Shape Memory Alloy (SMA) element to predict a response of the SMA element includes obtaining the resistivity of the SMA element over a range of a physical property of the SMA element; correlating variations in the obtained resistivity with respect to the physical property of the SMA element to identify behavioral differences in the resistivity for the different phases of the SMA element; calculating a rate of change of the resistivity of the SMA element over a period of time; calculating the derivative of the rate of change in the resistivity of the SMA element over the period of time; and comparing real time data of the physical property to the derivative of the rate of change to predict the response of the shape memory alloy element.

Abstract: A system for collecting frequency response data from a generator system including: applying a perturbing signal to a signal input of an exciter system for a synchronous generator; collecting data regarding signal output from a multiplicity of signal points in the exciter system; transforming the collected data to predict a signal response at a signal output in the system different from the signal points used for collecting data, and analyzing the frequency response of the system.

Abstract: An apparatus, method, and computer program are provided for automated closed-loop identification of an industrial process in a process control system. Multiple models (such as multiple model structure-model order combinations) can be identified, where the models are associated with a process to be controlled. One or more metrics (such as a prediction metric or rank) can be determined for each of the models. At least one of the models can be selected based on the one or more metrics. A final model for controlling the process can be provided (such as to a controller), where the final model is based on the at least one selected model. A band pass filter could be designed using some of the identified models. The band pass filter could be used to identify at least one other of the models or to determine at least one of the one or more metrics.

Abstract: A method for building robust model predictive controller universally applicable is presented based on the innate process characteristics independent of the method of control actuation. The method of universal MPC design permits proper configuration of requisite regulatory control loops for measured and unmeasured disturbance rejections consistent with the underlying innate process characteristics and their embedding within the overall process unit model predictive controller. The method of universal MPC design requires that manipulated variables process value based model (PV-based models) be used in control and optimization in place of the customary set point based models (SP-based models) or control output based models (OP-based models). The PV-based models are devoid of the manipulated variables regulatory controllers response and tuning. Based on the PV-based models, an alternate method of MPC called PV-based MPC is presented that is most robust and adaptable of possible three types of MPC.

Abstract: Process control system for detecting abnormal events in a process having one or more independent variables and one or more dependent variables. The system includes a device for measuring values of the one or more independent and dependent variables, a process controller having a predictive model for calculating predicted values of the one or more dependent variables from the measured values of the one or more independent variables, a calculator for calculating residual values for the one or more dependent variables from the difference between the predicted and measured values of the one or more dependent variables, and an analyzer for performing a principal component analysis on the residual values. The process controller is a multivariable predictive control means and the principal component analysis results in the output of one or more scores values, T2 values and Q values.

Abstract: A system and method is provided for evaluating the transient cooling performance of a data center. In one version, the method includes receiving input data from a storage device, the input data including data center architecture information and operating data, displaying a model of the data center, performing real-time transient cooling performance calculations for the data center using the input data, and displaying results of the real-time transient cooling performance calculations, wherein the results include a maximum predicted temperature of the data center following a power outage of the data center.

Abstract: For controlling a motion sequence of a machine element, with which the control of the motion sequence of the machine element is carried out based on a functional relationship between a master shaft and a slave shaft, the functional relationship IS ascertained with consideration for several conditions of this motion sequence. The functional relationship includes at least one first section, which is defined by an nth-order polynomial, and at least one second section, which is at least partially separated from the first section, and which is defined by an ath-order polynomial. In this case, “a” is less than “n”.

Abstract: An action analysis apparatus includes an acquiring unit that acquires moving image data including a series of frame image data obtained by imaging a human body, a unit that detects at least one image area in which a predetermined portion of the imaged human body is imaged in the frame image data included in the acquired moving image data and generates and stores information to identify the detected image area, and a unit that generates at least one of feature quantity information about an action of the predetermined portion of the human body detected in the frame image data and generates and stores information to identify frame image data at a timing at which the feature quantity information satisfies a predetermined condition as feature time point information. The feature time point information is applied to present the moving image data to a user.

Abstract: Controller scaling and parameterization are described. Techniques that can be improved by employing the scaling and parameterization include, but are not limited to, controller design, tuning and optimization. The scaling and parameterization methods described here apply to transfer function based controllers, including PID controllers. The parameterization methods also applies to state feedback and state observer based controllers, as well as linear active disturbance rejection controllers. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the application. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: Disclosed are an articulated hydraulic machine supporting, control system and control method for same. The articulated hydraulic machine has an end effector for performing useful work. The control system is capable of controlling the end effector for automated movement along a preselected trajectory. The control system has a position error correction system to correct discrepancies between an actual end effector trajectory and a desired end effector trajectory. The correction system can employ one or more absolute position signals provided by one or more acceleration sensors supported by one or more movable machine elements. Good trajectory positioning and repeatability can be obtained. A two joystick controller system is enabled, which can in some cases facilitate the operator's task and enhance their work quality and productivity.

Abstract: An advanced process control (APC) system, an APC method, and a computer program product, which, when executed, performs an APC method are provided for incorporating virtual metrology (VM) into APC. The present inventions uses a reliance index (RI) and a global similarity index (GSI) to adjust at least one controller gain of a run-to-run (R2R) controller when the VM value of a workpiece is adopted to replace the actual measurement value of the workpiece. The RI is used for gauging the reliability of the VM value, and the GSI is used for assessing the degree of similarity between the set of process data for generating the VM value and all the sets of historical process data used for building the conjecturing model.