Abstract: Method for the optimization of the surface geometry or of a variable, dependent on this, or variables, dependent on this, of bevel or hypoid gears for their production on a free-form machine which can be mapped to a free-form basic machine with at most six axes uniquely in a reversible way, even to symmetries, which has a gearwheel to be machined and a tool which are in each case rotatable about an axis, and the tool and the gearwheel to be machined are moveable, preferably displaceable or rotatable, with respect to one another along or about a plurality of axes, the optimization of the surface geometry or of the variable or variables, dependent on this, of the bevel or hypoid gearwheel taking place in that one or more control parameters, which has or have influence on the surface geometry or the variable or variables, dependent on this, of the bevel or hypoid gearwheel, is or are varied by means of a simulation of the gearwheel production process and/or a roll and/or a load-contact analysis on the free-form

Abstract: Roller cone drill bits may be formed with cutting elements and cutting structures optimized to increase downhole drilling life of an associated drill bit. The cutting zone, load zone and wear zone of each cutting element may be analyzed by finely meshing each cutting element into many small segments. The number of contacts between each meshed segment and portions of a downhole formation may be determined during discrete drilling time periods. A distribution of sliding velocity for each segment relative to portions of the downhole formation may also be determined during the discrete drilling time periods. Force profiles for each cutting zone may be used to determine associated loading zones. A wear profile for each cutting element may be estimated by combining the associated force profile with the associated distribution of sliding velocity.

Abstract: Method for the optimization of the surface geometry or of a variable, dependent on this, or variables, dependent on this, of bevel or hypoid gears for their production on a free-form machine which can be mapped to a free-form basic machine with at most six axes uniquely in a reversible way, even to symmetries, which has a gearwheel to be machined and a tool which are in each case rotatable about an axis, and the tool and the gearwheel to be machined are moveable, preferably displaceable or rotatable, with respect to one another along or about a plurality of axes, the optimization of the surface geometry or of the variable or variables, dependent on this, of the bevel or hypoid gearwheel taking place in that one or more control parameters, which has or have influence on the surface geometry or the variable or variables, dependent on this, of the bevel or hypoid gearwheel, is or are varied by means of a simulation of the gearwheel production process and/or a roll and/or a load-contact analysis on the free-form

Abstract: Embodiments of the disclosure provide a method and system used for searching among a plurality of entities on a computer network by a user. A computer server in communication with the computer network can include a database with a storage mechanism, a rule set, and an interaction calculation engine. The user can search for a first entity using a location calculation engine in communication with the computer network. The location calculation engine can locate the first entity and determine and display at least a second portion of the plurality of entities relevant to the first entity.

Abstract: This disclosure relates to a design methodology used in manufacturing a broaching tool for cutting slots in aerospace disk applications. The method includes modeling geometry of the slot and the broach tool, which is based upon an initial minimum tooth rise that is determined empirically for the particular disk material. The number of broach inserts and teeth per insert is calculated, and the broach inserts are modeled. The stresses and deformation of the lug are calculated in a finite elements environment based upon simulated incremental broach tool movements. If the lug is not within specifications based upon design constraints, then the broach tool is revised and the simulations are repeated until the slot is within the desired specifications.

Abstract: A computer-implemented method is provided for generating data representing an object involved in a computer-implemented simulation of a physical experiment. Data describing geometric dimensions and material for the object is received as input. The data may be broken down into data representing distinct components of the object. Data is generated that describes a base parent volume region that extends at least beyond extents of the geometric dimensions of a portion of the object. Next, data is generated that describes child volume regions produced by subdividing the base parent volume region into the child volume regions each having dimensions that are a fraction of the dimensions of the base parent volume region. The data describing each child volume region is examined to determine whether vertices of each of the child volume regions are in the interior or exterior of the portion.

Abstract: A method, system, and computer readable article of manufacture for simulating a mechanism system controlled by a plurality of electronic control units operating at different clock rates. The simulation system includes a mechanism system simulator; a plurality of electronic control unit emulators for electronically emulating the respective plurality of electronic control units, each thereby receiving an input signal with a time and giving an output signal with a time; and a scheduler for receiving and storing the output signals with the times from the plurality of electronic control unit emulators, and for providing, in response to a change in the output signal coming from the electronic control unit emulator and having a relatively late time, the output signal with a time preceding the relatively late time to the mechanism system simulator.

Abstract: Data from a target system (616) that exhibits a non-linear relationship between system properties and measurement data, is processed by applying a linear filter (F) to improve resolution and accuracy. The filter reduces inaccuracies that are introduced by an algorithm used to reconstruct the data. The filter is defined by assigning time varying functions, such as sinusoids (200), to elements (210) in a model (Y) of the system to perturbate the elements. The resulting data output from the model is reconstructed using the same algorithm used to subsequently reconstruct the data from the target system. The filter is defined as a matrix (F) that transforms the reconstructed data of the model (X) back toward the known properties of the model (Y). A library of filters can be pre-calculated for different applications. In an example implementation, the system is tissue that is imaged using optical tomography.

Abstract: An inductive rotary joint for non-contact transmission of electrical energy between a stationary part and a rotating part of the rotary joint comprises a power generator for generating an alternating voltage or an alternating current, which feeds a load by means of a rotatable power transmitter. An electrical parameter on the primary side of the power transmitter is determined with a measurement means, and from this, the condition of another electrical parameter at the load is approximated by means of a functional unit. Regulation of the power generator is effected with this approximated value.

Abstract: A system, method and software product for defining material properties hierarchically in a finite element analysis of a structure is disclosed. As a material type is created, the type is checked whether it is a root material type. If so, all of the material properties are defined explicitly in the current definition. Otherwise, the parent material type is searched and located first until the traversing finds a root definition. All of the material properties of the parent material type(s) found are read in and stored as the base properties of the material to be created. The material properties explicitly defined in the current definition of the material will either overwrite or add to the base properties. The material properties definition resembles a hierarchical tree: each of the material properties type has a parent material except the root material type which is on the top of the tree.

Abstract: A method for determining an optimized arrangement of cutting elements about a roller cone bit is provided. Also provided is a roller cone drill bit having cutting elements that are arranged according to a computerized optimization routine.

Abstract: Methods for computer-implemented simulation for the interaction of two or more objects are provided. Data describing particles that represent each of the objects is generated from geometric data for objects. The data for each particle describes a mass density, velocity and energy at a position of the corresponding object. The particles are grouped into sectors to define a computational mesh comprising a plurality of sectors, wherein each sector is a volume region at a position in space in which particles associated with the objects may reside. For each of a plurality of select particles, so called neighboring particles are determined that are within a region of influence with respect to a select particle. Computations are performed based on laws of conservation of mass, energy and momentum to produce updated values for mass, velocity, energy, pressure, stress and position for the particles at each of a plurality of time steps.

Abstract: An image display system and method that use physical models to produce a realistic display of a scene are disclosed. The image display method involves operating a computer having a display screen, a memory and a processing unit for simulating the motion of objects and displaying the results on the display screen.

Abstract: A method for designing gas turbine engine components using a coupled parametric analysis of part geometry and flow control is disclosed. Included are the steps of parametrically defining the geometry of the duct wall shape, parametrically defining one or more flow control actuators in the duct wall, measuring a plurality of performance parameters or metrics (e.g., flow characteristics) of the duct and comparing the results of the measurement with desired or target parameters, and selecting the optimal duct geometry and flow control for at least a portion of the duct, the selection process including evaluating the plurality of performance metrics in a pareto analysis. The use of this method in the design of inter-turbine transition ducts, serpentine ducts, inlets, diffusers, and similar components provides a design which reduces pressure losses and flow profile distortions.

Abstract: A machining simulation apparatus is arranged in a machine tool having a tool holding mechanism, a workpiece holding mechanism, a drive mechanism and a numerical controller, and provided with: an actual CCD camera for imaging a tool held by the tool holding mechanism and the workpiece holding mechanism not holding a workpiece to generate actual image data; a model data update processing section for generating model data relating to when moving the holding mechanisms based on the operation command received from the numerical controller and the model data of the holding mechanisms, tool and workpiece; a virtual image generation processing section for generating virtual image data of the tool and workpiece based on the generated model data; and a rendering processing section for generating composite image data by superimposing the virtual image on the actual image, and displaying the composite image data on a screen display device.

Abstract: A joint simulator is provided having a housing with a chamber, a piston, slidable within the chamber, and a shaft rotatable within the housing, the shaft having (i) an end configured to engage a power tool to be tested, and (ii) a threaded end engaged with the piston, whereby rotating the shaft causes the piston to slide within the chamber Hydraulic fluid fills a section of the chamber formed by a side of the piston and the housing, and computer software controlled pressure and relief valves are actuated to regulate the flow of hydraulic fluid in the chamber, to achieve target pressures. The pressure of the hydraulic fluid creates resistance to rotation of the shaft, thereby increasing the torque relative to the angular increase on the shaft and/or relative to time.

Abstract: A design support system is provided, which accurately simulates the behavior of a flexible medium in a convey path even if the flexible medium exhibits different flexural stiffness in different bending directions. In a design support system which supports the user to design a convey path by simulating the behavior of a flexible medium conveyed in the convey path, a flexible medium model creation module (102), when a flexible medium to be conveyed is defined in the convey path defined by using a convey path definition module (101), creates a flexible medium model representing the flexible medium by segmenting the flexible medium into a plurality of stiff body elements each having a mass, and connecting the respective adjacent stiff body elements with two springs, that is, a rotational spring and translational spring whose spring constants change depending on the direction of flexural deformation of the flexible medium.

Abstract: Techniques for creating a finite element model are disclosed that include various processes including: superimposing a rectangular array of nodes and nodal-pointers onto a wire-frame geometry, and creating a set of geometric-elements using the rectangular array.

Abstract: A method of computer-based simulation of a cooling system includes inputting condenser parameters, evaporator parameters and compressor parameters for the cooling system and processing the condenser parameters, the evaporator parameters and the compressor parameters through a model of the cooling system. A flow control device is selected based on an output of the model.

Abstract: A method and a device for simulating process flows in the graphics industry and for displaying the result calculated in the simulated process flows. The method is characterized by the following steps: inputting and/or selecting at least one order data set inputting and/or selecting at least one process data set calculating links between order data set and process data set as a function of the order data set and the process data set creating a process flow from the calculated links calculating the result and/or intermediate results for a process flow using the underlying order data set outputting the result and/or intermediate results.

Abstract: There is described a method for controlling and/or monitoring a movement of a free body in an industrial machine, wherein the industrial machine comprises an actuator for carrying out a movement, wherein the movement of at least one free body is either mechanically coupled to the movement of the actuator and/or is decoupled from the movement of the actuator. At least one of the following physical variables of the free body: weight, density, frictional parameters, geometric form and/or center of gravity is input into a simulation program, whereupon with the aid of at least one of these physical variables, the movement of the free body is simulated, wherein the simulation takes place, in particular, in real time. This enables a better simulation of dynamic and/or static processes in an industrial machine.

Abstract: A computationally efficient general method of modeling or simulating matrix acidizing treatment when flow is not axisymmetric involves determining streamlines in the general flow field using complex potential theory to solve for the flow along the streamlines. The flow over a time step is used to model the propagation of the acid front and the creation and extension of wormholes.

Abstract: There is a method for modeling the surface fatigue life of a mechanical component. The method has the following steps: a) modeling the surface fatigue life of the mechanical component on an atomistic scale to form an atomistic model, b) modeling the surface fatigue life of the mechanical component on a mesoscale to form a mesoscale model, c) modeling the surface fatigue life of the mechanical component on a macroscale to form a macroscale model, and d) testing the surface fatigue life of the mechanical component. Feedback from the macroscale model is employed at least once to validate the atomistic model. Feedback from the macroscale model is employed at least once to validate the mesoscale model. Feedback from the testing is employed at least once to validate the macroscale model. There is also an interactive, multiscale model for prediction surface fatigue life or degradation rate for a mechanical component.

Abstract: A process and device for simulating a product printed by a virtual press. The process implemented by the device includes creation of a three-dimensional object page, selection of at least one fold among a set of predetermined folds, with the selected folds corresponding to the folds produced on the product to be simulated, for each fold produced and selected, a modification of the three-dimensional object page by the addition of at least one fold line at a given position on the three-dimensional object page, construction of the simulated product starting from the modified three-dimensional object page, and a display of the simulated product constructed in this manner.

Abstract: Various embodiments of systems and methods are described in which system simulation techniques are combined with graphical programming techniques in a common environment. For example, various embodiments of the methods comprise displaying a graphical data flow diagram connected to a system diagram, e.g., where the graphical data flow diagram and the system diagram are displayed together in a compound diagram. In the displayed compound diagram, the graphical data flow diagram may be connected to the system diagram, e.g., by a line or wire. In one embodiment the wire may visually indicate that the graphical data flow diagram is executable to produce a value that is provided as an input signal for a simulation performed based on the system diagram. In another embodiment the wire may visually indicate that the graphical data flow diagram receives an output value from the system simulation as input.

Abstract: In a gear cutting simulation method and device, a gear-cutting-machine model which specifies relative positions between a blank model and a cutter model is created. A gear model is created as a result of simulation of gear cutting which is performed with the blank model and the cutter model arranged in the gear-cutting-machine model.

Abstract: The invention starts with a method to determine a blank form of an elastic component, in particular a non-articulated wiper arm (10), with the default of a target form, which the elastic component is supposed to assume under the effect of at least a predefined initial force (F1). It is proposed that a counter force (FG) that at least essentially opposes the predefined initial force (F1) is applied to a working model (12) of the elastic component, whose model blank form is at least similar to the target form.

Abstract: The present invention provides a peel strength simulating apparatus which simulates peel strength between a semiconductor integrated circuit chip and a resin package bonded to each other. The apparatus includes a storage section which stores plural types of parameters. The apparatus also includes a parameter specifying section which specifies a changeable parameter whose numerical value is changeable from the plural types of parameters stored in the storage section and specifies change priorities when specifying plural types of changeable parameters. The apparatus further includes a simulating section which repeats simulation of the peel strength until the peel strength exceeding a predetermined threshold value is obtained while changing the numerical values of the specified changeable parameters according to the specified priorities.

Abstract: Systems and methods are provided for determining data center cooling and power requirements and for monitoring performance of cooling and power systems in data centers. At least one aspect provides a system and method that enables a data center operator to determine available power and cooling at specific areas and enclosures in a data center to assist in locating new equipment in the data center.

Abstract: Disclosed are techniques for representing and modeling one or more systems in which each system corresponds to an application mode. This may be done for one or more geometries using local and/or non-local couplings. For each application mode, physical quantities are modeled and may be defined using a graphical user interface. Physical properties may be used to model the physical quantities of each system. The physical properties may be defined in terms of numerical values or constants, and mathematical expressions that may include numerical values, space coordinates, time coordinates, and actual physical quantities. Physical quantities and any associated variables may apply to some or all of a geometric domain, and may also be disabled in other parts of a geometrical domain. Partial differential equations describe the physical quantities. One or more application modes may be combined using an automated technique into a combined system of partial differential equations as a multiphysics model.

Abstract: A method, and the resultant apparatus, for designing a fire resistant structural beam, such as a computer-aided design of a fabricated steel beam having an intumescent coating material, by obtaining a number of values for a number of physical parameters of the structural beam, including reading temperature information that comprise empirical information derived from heating a structural beam and a number of temperatures at a number of locations.

Abstract: A system and method are described for generating a model of an environment in which a plurality of equipment units (104) are deployed for the extraction of at least one resource from the environment. The system comprises a pre-extraction or in-ground modelling unit (204) configured to receive data from a first plurality of heterogeneous sensors in the environment and to fuse the data into a pre-extraction model descriptive of the environment and the at least one resource. An equipment modelling unit (208) is configured to receive equipment data relating to the plurality of equipment units operating in the environment and to combine the equipment data into an equipment model. A post-extraction or out-of-ground modelling unit (206) is configured to receive data from a second plurality of sensors and to fuse the data into a post-extraction model descriptive of material extracted from the environment, wherein at least one of the equipment units operates to extract the at least one resource from the environment.

Abstract: Methods and systems may be provided simulating forming a wide variety of directional wellbores including wellbores with variable tilt rates and/or relatively constant tilt rates. The methods and systems may also be used to simulate forming a wellbore in subterranean formations having a combination of soft, medium and hard formation materials, multiple layers of formation materials and relatively hard stringers disposed throughout one or more layers of formation material. Values of steer force, bit walk rate and average walk rate from such simulations may be used to design and/or select drilling equipment for use in forming a directional wellbore.

Abstract: The present invention relates to a method and system for describing the motion of a closed-loop multibody mechanism. In this case, equations of motion need to be obtained for constrained multibody systems. The invention is based on a forward dynamics formulation resulting in a recursive Hamiltonian formulation for closed-loop systems using generalised co-ordinates and conjugated canonical momenta. The method allows to limit the number of arithmetical operations necessary to obtain the equations of motion with a good evolution of the constraints violation errors. Calculations can be performed based on constrained articulated momentum vectors.

Abstract: A real-time simulation method for thin shells undergoing large deformation is provided. Shells are thin objects such as leaves and papers that can be abstracted as 2D structures. Development of a satisfactory physical model that runs in real-time but produces visually convincing animation of thin shells has been remaining a challenge in computer graphics. For real-time integration of the governing equation, a modal warping method for shells is developed. This new simulation framework results from making extensions to the original modal warping which was developed for the simulation of 3D solids.

Abstract: A printing press simulator for a printing press includes a simulation unit, which simulates a printing process or the behavior of a printing press on the basis of input data specified for the simulation and generates output data for displaying the results. The simulation unit accesses, for the purpose of the simulation, a database, which contains real printing press data recorded on the same model of printing press.

Abstract: For determining the behavior of a flexible system submitted to predetermined displacement boundary conditions, a process uses geometrically non-linear finite element analysis. The process has a plurality of incremental steps within a total Lagrangian formalism with co-rotational update. In each incremental step, one computes for a finite element of the flexible system a displacement vector, having translational and rotational components, at the nodes of the finite element. This computation of the displacement vector is carried out by minimizing the energy of the flexible system when the system is submitted to a fraction of the predetermined displacement. For a given finite element, the co-rotational update is carried out by computing an updated elementary frame of reference, without considering the bending rotational components of the displacement vectors computed at the nodes of the finite element. The properties of this co-rotational update make all computations similar, hence simpler and easier.

Abstract: For a plurality of combinations of a plurality of operating states included in an operating range of an engine and for a plurality of combinations of a plurality of objective variables, a system, which calculates design variables, includes a calculating device for obtaining global optimal solutions of the design variables that minimize or maximize a sum of the plurality of objective variables, which respectively correspond to the plurality of combinations of the plurality of operating states; a receiving device for receiving designation of an upper limit or a lower limit of the plurality of objective variables; and a searching device for searching for global optimal solutions that result in the smoothest change in the design variables when changing the operating states in a range of the received upper limit to the received lower limit of the objective variables, with one of the global optimal solutions as an initial value set.

Abstract: A method of eliminating information on the projection states of projection elements (P) by using an analysis model in which discharged projection elements (P) repeatedly collided with rotation blades (13) in a projection machine having rotating blades (13). The method comprises the step of determining initial conditions including information on the size and rotation of blades (13), discharging information on the projection elements (P), and information on projection elements with respect to the blades (13) the step of storing the initial conditions, a computing step of computing the position of each projection element (P), and its velocity and direction after collision with a blade (13) based on the initial conditions, and the step of estimating information on projection state based on computation results.

Abstract: A numerical model related to fluttering of an insect, when an equivalent model of actual structure of a wing of the insect is moved in the air in accordance with a model of fluttering motion of the wing of the insect is calculated by fluid-structure interactive analysis, in which behavior of the wing and behavior of the air are given as numerical values, including interaction therebetween. Thereafter, a method of controlling a fluttering robot, wing shape and the like are determined by modifying numerical models of fluttering of an insect prepared by fluid-structure interactive analysis, in accordance with sensitivity analysis. Accordingly, a method of preparing numerical models of wing and air considering the behavior of the wing of the insect in the air is provided and, in addition, a method of manufacturing a fluttering robot utilizing the numerical model prepared by this method of preparing numerical model can be provided.

Abstract: A complex product is composed of several parts, where each part may depend on the other. As a consequence of these inter-dependencies, the selection of one part might exclude other parts from being included in the finished product. A consistent configuration is a selection of parts where all inter-dependencies are satisfied. A computer program for computer-assisted configuration helps an end-user to make choices that will lead to a consistent product. The preferred embodiment of the present invention, Virtual Tabulation, is a method for keeping track of inter-dependencies among a large number of parts, to allow for the construction of an efficient and exact configuration program. Such a program allows interactive configuration over networks (e.g., the Internet). Another aspect of the invention, called Smart Search, allows a set of inter-dependencies among parts to be computed from a product database.

Abstract: A method for determining virtual visibility is disclosed. The method includes modeling at least one object in a virtual space and plotting at least one surface from a first predetermined location relative to the at least one object within the virtual space. The method further includes identifying at least one interference between the at least one object and the at least one surface. The method still further includes determining a first characteristic of the at least one interference and determining if the first characteristic is within a predetermined range.

Abstract: The invention aims at providing an engine control experimenting apparatus which enables to easily carry out a confirmation test of an operation in all operation states with regard to the performance of various engine control parts constituting an engine system. In this engine control experimenting apparatus, various engine control parts, which are actually mounted on an engine and are required for engine control, are constructed in a state where electrical transmission and fuel supply are enabled in a manner similar to a case where the engine control parts are mounted on a real engine, and a model-based control is performed on the same conditions as those of the actual engine, on the basis of experimental data of the real engine written in an electronic control unit constituting each of the engine control parts.

Abstract: When the convey behavior of a flexible medium conveyed in a conveying path is analyzed by simulation, a design support apparatus of this invention executes 1) processing for approximating a nip on a model to an actual nip, 2) processing for matching a feature point of a drive chart with a calculation step upon making a numerical calculation for solving a motion of a flexible medium using the drive chart, and 3) processing for reflecting velocity variations due to deformation of a convey roller pair, thus implementing a simulation with high accuracy. When the design support apparatus of this invention is used, even a designer who does not have expert knowledge on simulation can analyze the convey behavior of the flexible medium conveyed in the conveying path with relatively higher accuracy.

Abstract: A method is disclosed. The method includes receiving a first polygon, receiving a second polygon, calculating a vector joining a centroid of the first polygon and a centroid of the second polygon, retrieving vertices of each polygon that are farthest from the other polygon in the direction of the vector towards the other polygon, performing a view frustrum from each vertex retrieved for the first polygon to the centroid of the first polygon, performing a clipping operation on the second polygon and determining if the second polygon intersects the view frustrum of one or more of the vertices of the first polygon.

Abstract: A method of designing a roller bearing is disclosed upon clarifying mechanisms of damage patterns in respect of two kinds of brinelling, involved in the bearing, wherein white-banded flaking (brittle flaking) is a plastic instability phenomenon appearing under high-speed deformation accompanied by adiabatic shear deformation status with the resultant occurrence of adiabatic shear band (also called white band) inside material of the bearing. This enables all of the damage patterns to be determined upon making comparison between shear strain and shear strain rate, occurring inside the bearing, and discriminated values.

Abstract: In a simulation game machine for play on the basis of images of three-dimensionally constituted terrain features and characters which are represented as if viewed from a prescribed camera within a virtual space, allows the viewing point to be shifted in three dimensions while looking over a stage, thereby enhancing the interest of the game. Upon entering a topographical mapping data check, the viewing point is shifted while panning and zooming in movie-like fashion along a predetermined path, and messages disposed along the path are displayed.

Abstract: Modeling and simulation of free and forced structural vibrations is essential to an overall structural health monitoring capability. In the various embodiments, a first principles finite-difference approach is adopted in modeling a structural subsystem such as a mechanical gear by solving elastodynamic equations in generalized curvilinear coordinates. Such a capability to generate a dynamic structural response is widely applicable in a variety of structural health monitoring systems. This capability (1) will lead to an understanding of the dynamic behavior of a structural system and hence its improved design, (2) will generate a sufficiently large space of normal and damage solutions that can be used by machine learning algorithms to detect anomalous system behavior and achieve a system design optimization and (3) will lead to an optimal sensor placement strategy, based on the identification of local stress maxima all over the domain.

Abstract: A method and a device for operating a machine tool are disclosed, wherein a machining operation of the machine tool is controlled by a parts program by storing a simulated configuration of the machine tool in the parts program, determining an actual configuration of the machine tool, comparing the actual configuration with the simulated configuration of the machine tool stored in the parts program, and generating a warning message if the actual configuration is not in conformance with the simulated configuration. This prevents errors in the machining process resulting from a discrepancy between the configuration of the machine tool used in the simulation of the parts program and the configuration of the actual machine tool during the actual machining operation.

Abstract: A method for designing a drill bit that involves simulating a drill bit having cutting elements disposed thereon is provided. In particular, the method involves determining at least one drilling performance parameter while simulating drilling in a selected earth formation.