Abstract: In one embodiment, the invention includes a method for estimating seismic signal propagation raypaths from seismic source locations through a subsurface formation to seismic receiver locations. Raypaths are determined which minimize the value of an expression which is a function of travel time and distance between a source location and a receiver location. The value of the expression depends on the value of a parameter which balances the weighting of travel time and distance in the expression.

Abstract: A master scheduler which interfaces with several heterogenous simulators simulating individual modules of an integrated circuit. The master scheduler receives data indicating the modules assigned to each simulator and the interconnections of the modules. The master scheduler forwards output signals generated by one simulator to any other simulators as specified by the interconnection data. As a result, functional verification of an entire integrated circuit can be performed even if only portions can be simulated by corresponding simulators.

Abstract: Methods for evaluating drill pattern parameters such as burden, spacing, borehole diameter, etc., at a blast site are disclosed. One method involves accumulating the burden contributed by successive layers of rock and matching the accumulated rock burden to a target value for a borehole having a length related to the average height of the layers. Another method relates to varying drill pattern parameters and characteristics to match blast design constraints, including the substitution of one explosive material for another by the proper balance of materials and/or output energies to the associated rock burden. Analysis of deviations from target rock burdens and corrective measures are disclosed, as well as cost optimization methods. The various methods can be practiced using an appropriately programmed general purpose computer.

Abstract: A method for determining a model for a welding simulation, and the associated model. The method includes the steps of determining a history annihilation model of a material being welded, determining a strain hardening model of the material being welded, determining a three-dimensional virtual elements detection model of the material being welded, and incorporating the above models into a constitutive model for the welding simulation.

Abstract: A seismic data set is processed by selecting a set of gathers in the seismic data set. A frequency independent constraint matrix is calculated in a first gather. A model solution in at least one second gather is calculated by using the constraint matrix in a high-resolution Radon transform.

Abstract: A device and method identify and compensate for tensile and/or shear stress due to heat-caused expansion and contraction between an integrated heat spreader and thermal interface material. This device and method may change the shape of the integrated heat spreader based upon the identification of location(s) of high tensile and/or shear stress so that additional thermal interface material may be deposited between the integrated heat spreader and a die in corresponding locations. Utilizing this method and device, heat is efficiently transferred from the die to the integrated heat spreader.

Abstract: The present invention includes a method and apparatus for simulating, for example on a desktop computer, a specific view of a hologram. A preferred embodiment of this invention suitably enables, in medical imaging, the manipulation of intensity transformations (windowing and leveling), regions (cropping) and views (axial, coronal and lateral) and the display of the resulting simulations in substantially real time. In accordance with one aspect of the present invention, an approximation of substantially accurate pixel intensities is achieved by collapsing three-dimensional data onto a two-dimensional view, without the need for constructing complex summations of fringe patterns, as is typically required when constructing a hologram. A power function is suitably applied to each voxel in the data set. The values for a particular x, y coordinate are then summed along the z axis, with the resultant sum value being stored in a sum buffer for all values of x and y.

Abstract: A method and a device by which original digital signals are analysis-filtered, where the original digital signals include original samples representing physical quantities, and where the original samples are transformed by successive calculation steps into high and low frequency output samples. Any sample calculated at a given step is calculated by a predetermined function of the original samples and/or previously calculated samples, where the samples are ordered by increasing rank. The signal is processed by successive input blocks of samples, where the calculations made on an input block under consideration take into account only the original or calculated samples belonging to the input block under consideration, and where the input block under consideration and the following input block overlap over a predetermined number of original samples. Output blocks are formed, where each output block corresponds respectively to an input block.

Abstract: The present invention provides a method and apparatus for simulating an aerial image projected from an optical system, wherein the optical system includes a pupil and a mask. In general, the method comprises the steps of obtaining parameters for the optical system, calculating a kernel based on an orthogonal pupil projection of the parameters of the optical system onto a basis set, obtaining parameters of the mask, calculating a vector based on an orthogonal mask projection of the parameters of the mask onto a basis set, calculating a field intensity distribution using the kernel and the vector, and obtaining aerial image data from the field intensity distribution.

Abstract: A set of specially-configured LUT's are used in a rasterizing portion of a graphics system for simulating Sensor-assisted Perception of Terrain (SaPOT) so that simulation of the image produced by a given sensor can proceed rapidly and with good accuracy at a per-texel level of resolution. More specifically, terrain texels-defining memory is provided with a plurality of addressable texel records where each record contains: (a) one or more material identification fields (MID's); (b) one or more mixture fields (MIX's) for defining mixture proportions for the materials; and (c) slope-defining data for defining a surface slope or normal of the corresponding texel. A sky-map LUT is provided for simulating the act of looking up to the sky along the normal surface vector of a given texel to thereby obtain a reading of the sky's contribution of illumination to that terrain texel.

Abstract: A method, computer readable medium and a structure for real-time simulation, which allows the user to manipulate model parameters and see the simulated result in real-time as the model is changed. The simulated result is visually compared with the data, allowing the user to refine the model. In one embodiment, the invention is used for evaluating medium energy ion scattering (MEIS) data, as well as conventional Rutherford backscattering data. It is important to realize that the invention is not limited to ion beam analysis, or to scientific data analysis. The invention can be used for evaluating any type of complex system where a well-defined simulation procedure exists. The model evaluation must proceed quickly enough to provide a real-time, visual display for the user.

Abstract: A method for interpolating the environment and geological age at all levels in a borehole from information provided by a limited number of depths and the use of a synthetic stratigraphic cross-section for the interval between these depths. In hydrocarbon exploration, a borehole provides a suite of logs, plus estimates of geologic age at a number of spaced markers. This method uses a sea-level cycle chart, a calculation of subsidence from the thickness of the interval, and postulated values for several variables. If it is known that the supply of sediment always exceeded the available accommodation during deposition, the corresponding synthetic cross-section may then be optimized for geological plausibility (as gauged by visual observation or quantitative criteria) by perturbing the postulated variables and iterating the calculations.

Abstract: A method and apparatus for mesh-free engineering analysis of geometric models is described. The method and apparatus, which are preferably software-based and implemented on personal computers or other programmable processing devices, represent geometric models by implicit mathematical functions. The implicit functions allow interpolation of all desired boundary conditions over the geometry without meshing, and the boundary conditions may then may be combined with a piecewise continuous model of the solution structure (i.e., the analysis problem). By solving for elements of the solution structure (its basis or coordinate functions) which satisfy the given boundary conditions either exactly or approximately, the solution structure will define the behavior and boundary conditions (exactly or approximately) throughout the geometric model.

Abstract: The invention relates to a method of performing channel simulation and a channel simulator. The channel simulation is performed digitally. At least a section of a signal (206) to be fed to simulation is transformed by convolution transformation from time space to transformation space in tansformation means (200) of the channel simulator. In weighting means (202), the transformed signal (208) is weighted by a channel impulse response that is transformed from time space to transformation space. Finally, the resulting signal (210) is inverse-transformed in inverse-transformation means (204) to time space.

Abstract: The invention concerns a method which consists in: obtaining a physical model of phenomena involved when an object or product is subjected to a crushing test, said modelling taking into account elastic deformation, plastic deformation and relaxation; adjusting said model to experimental data and characterising the object or product from the adjusted model by means of parameters other than the crushing amplitude value, relative to energy dissipation during deformation, load relaxation or even energy accumulation during deformation. The invention enables to obtain more discriminating and more descriptive data concerning mechanical properties of the objects or products.

Abstract: The problem of detecting sedimentary formations having an abnormally high fluid pressure that are underneath a relatively impermeable formation having normal fluid pressures is addressed. At shallow depths, a formation with abnormally high fluid pressure has a shear velocity that is close to zero, and is thus significantly different from the shear velocity of overlying sediments. The high shear wave velocity contrast is detected by measuring a change in the amplitude of seismic waves reflected from the top of the abnormally pressured formation. This may be done by an amplitude versus offset (AVO) analysis of the reflected amplitudes of compressional or shear reflections. Measurements of the amplitude of reflected shear waves from a formation at some depth below the anomalous zone are may also be used to detect the presence of abnormally pressured intervals with low shear velocity and high shear wave attenuation.

Abstract: A method for calculating the intensity of an electromagnetic field emitted from a device and a storage medium for storing a program of the method are disclosed. The method uses a moment method in which a mutual impedance between shell elements and a supplied voltage are assumed to be known quantities and the current flowing through the shell element is assumed to be an unknown quantity.

Abstract: Methods and systems for magnetostatic modeling of a magnetic object is disclosed. A varying surface charge density is established at a surface of a magnetic object modeled by a magnetostatic model. Thereafter, a varying magnetic charge is generally distributed throughout a volume of the magnetic object to thereby accurately and efficiently model the magnetic object across a wide range of magnetic curves utilizing the magnetostatic model. The magnetic curves can be configured to generally comprise at least one non-linear magnetic curve and/or least one linear magnetic curve. Such magnetic curves may also comprise at least one magnetic curve in a magnetized direction and/or non-magnetized direction. Such magnetic curves are generally referred to as “BH curves”.

Abstract: The invention is a method for direct updating, by dynamic production data, of a fine geologic model representative of the distribution, in a reservoir, of a physical quantity characteristic of the subsoil structure. The method couples inversion and upscaling techniques allowing optimization of petrophysical parameters of a rougher simulation model resulting from the fine geologic model. Direct parameterization of the fine geologic model is performed followed by upscaling only as a means of obtaining rapidly an approximation of simulation results and of derivatives thereof in relation to the parameterization of the fine geologic model. The model has applications for determination of a development scheme such as optimizing the production of a hydrocarbon reservoir.

Abstract: A method of data compression for continuous or piecewise linear curves in two variables is presented which can guarantee that any compression error is exclusively on one selected side of the curve. Limiting errors to one side is required when simulating integrated circuit performance to determine if a design will have speed-related problems. In such a simulation it is necessary to calculate both the minimum and maximum possible time delays for a logic chain of circuit elements. Data compression of the transistor or gate voltage versus time relationship is necessary to reduce the very large amount of data that is required for the simulation. Data compression may introduce errors into the data in either direction. If it is necessary to have any possible error confined to one side of the curve, the compressed data must be shifted toward the desired error side by at least the maximum possible data error.

Abstract: A system for interacting with a database report is disclosed. The database is responsive to a query to produce an associated report comprising one or more objects, each object comprising a plurality of attributes. The system comprises means for storing one or more reports from respective database queries; and means for rendering at least one object from the stored reports. A user interface enables a user to navigate through objects composing the stored reports to select an object; select one or more attributes of the selected object and determine a value of a selected attribute to be used as a condition in a subsequent database query. A query generator receives the selected attribute values and generates the subsequent database query.

Abstract: A method of reducing the computer calculation time of a superposition is disclosed. A computing device having an input unit, an output unit, a memory unit, and an operation unit, is used to calculate the model superposing the function with shifted value of the variable. The model operator is formed by superposing a delta function in the same manner as the superposition of the function. The convolution of a model operator and the function is determined to thereby reduce the calculation time of the model superposing the function with the shifted value of the variable.

Abstract: Input seismic data are re-gridded to an arbitrary output grid by output-based azimuth moveout. An input seismic data set corresponding to an input grid is used to generate an equivalent output seismic data set corresponding to an output grid different from the input grid. Preferably, the output grid is divided into blocks, and each output grid block is assigned to one of a plurality of independent parallel processors. For each output trace corresponding to an output location, the contributions of plural input traces to the output trace are computed according to an azimuth moveout operator. The contributions are then summed into the output trace.

Abstract: The present invention relates to a method of controlling the quality of seismic data that has been migrated using the generalized Radon transform, the method serving to pass between a seismic data space and a migrated image space, in which method a parameter table is calculated giving, for a seismic wave going from a point of the image to a source or a sensor, its path length, its travel time, and the angles of incidence of the wave at the beginning and at the end of the path, and in which correspondence is established between at least one zone of a first one of said two spaces and at least one zone of the second space, by using said parameter table to fill in a correspondence table QCimage.

Abstract: In generating a parallax image string used for generating a holographic stereogram, the image quality of a stereoscopic image generated from the parallax image string is to be maintained as the time needed in imaging the parallax image string is shortened. To this end, an optimum number of image frames of each of plural parallax image strings are photographed in agreement with the localized position of the reproduced image of a generated holographic stereogram. The image processing is executed for equating the numbers of frame images of the parallax image strings. The parallax image strings having the equal number of the frame images of the parallax image strings are synthesized by, for example, chroma key synthesis to generate a new parallax image string.

Abstract: The invention concerns a method for analyzing results of antimicrobial susceptibility tests of micro-organisms, the test consisting in summarily identifying which species the micro-organism belongs to and measuring the minimum inhibitory concentrations (CMI) of several antimicrobial agents for said micro-organism. The method uses a database classifying the micro-organism species and the resistance mechanism to various antimicrobial agents, and containing, for each species and each resistance mechanism, parameters characteristic of the frequency distribution of minimum inhibitory concentrations for a group of antimicrobial agents.

Abstract: A system and method for statistical design of an ultrasound probe and imager system, and an associated graphical user interface for selecting input parameters to be used in an ultrasound simulation. The process and computer code allow the performance of a probe and imager combination to be specified and jointly optimized in image quality terms. The designs produced optimize both the image quality and other CTQ (critical to quality) parameters, such as the distribution of regulatory power indices and mechanical index. These CTQs indirectly affect image quality through their effect on patient dose. The Transducer Design Advisor incorporates a graphical user interface for facilitating selection of a parameter set to be used in the simulation. The user selects a desired parameter set by navigating across and interacting with a succession of windows. The user specifies various geometric characteristics of the transducer and how the user wants to simulate the imager system.

Abstract: A physical quantity at a given position in an analysis space is expressed by using a Poisson's equation, a Green's function and the Green's theorem. The equation thus obtained is substituted into an unknown parameter in the equation, to be expanded into infinite series. Stopping the expansion when the equation is expanded to some degree, the equation can be expressed only with known parameters such as boundary conditions. Through calculating the respective values of integrations included in terms of the series by the Monte Carlo method and adding them up, a physical quantity at a given position can be thereby obtained. Further, by the same method, a parasitic element constant at a given position in the analysis space can be also obtained. With this method, a simulation is achieved for obtaining a physical quantity and a parasitic element constant at a given position in an analysis space, without solving a matrix equation.

Abstract: The SQL compiler and SQL executor in a database management system are extended to process queries requiring streaming mode processing of data stored in a table. A scan operator performs table access functions during execution of the streaming mode query. The scan operator first performs an initial scan to access rows in a specified database table, and then performs a delta scan to access new rows added to the table, as well as rows modified by other queries. The scan operator continues to process new data added to the table until the initiating user or application closes the associated cursor. A set of data structures are provided to keep track of active scan operators, including a session control block that includes fields for keeping track of whether the scan operator is performing an initial scan or a delta scan. The session control block also includes, for streaming mode scan operators, a delta scan list of new and modified rows to be processed in the delta scan.

Abstract: An independent current source and a voltage-dependent source are arranged at each of ports, and a voltage at each of the ports is calculated with a circuit analysis. A voltage source is arranged at each of the ports by using the calculated voltage value, and a current flowing in an analysis target is calculated with an electromagnetic wave analysis. An analysis time is incremented stepwise, and the calculation of the voltage at each of the ports and the calculation of the current flowing in the analysis target are repeated. As a result, an electromagnetic field intensity calculation can be made with high accuracy even for an analysis target where a plurality of ports exists between a circuit analysis model and an electromagnetic wave analysis model.

Abstract: The present invention relates to a method, system, and program product for utilizing metawords to find electronic documents. According to the method of the present invention, a user specifies an initial search expression that includes at least one metaword. It is determined that the at least one metaword corresponds to a boolean expression, and, in response, an expanded search expression is generated. The expanded search expression includes the boolean expression in lieu of the at least one metaword, such that the expanded search expression is utilized in lieu of the initial search expression to find the electronic documents. In an illustrative embodiment, the determining step includes the step of determining that one or more terms and a count qualifier are associated with the at least one metaword. The count qualifier specifies a threshold number of occurrences of the one or more terms within a single electronic document.

Abstract: Temporal and/or spatial frequencies of spatially and digitally sampled 2-D or 3-D seismic data above the Nyquist frequency are preserved in full time migration of partial time migration (DMO) of 2-D and 3-D are preserved. Use is made of the fact that migration operators applied to input seismic data produce an output that need not correspond to prespecified temporal or spatial sampling values, and for sufficiently long migration operators, gives substantially uniform sampling at higher rates than the spatial and temporal Nyquist frequencies. Exact values of the partial migrated outputs are accumulated in an output buffer prior to combining them to give a migrated output with high temporal and/or spatial frequencies preserved.

Abstract: The present invention comprises receiving speech input from two or more speakers, including a first speaker (such as a customer service representative for example); blocking a portion of the speech input that originates from the first speaker; and processing the remaining portion of the speech input with a computer. The blocking and processing are real-time processes, completed during a conversation. One example is a method for de-cluttering speech input for better automatic processing, by removing all but the pertinent words spoken by a customer. Another example is a system for executing methods of the present invention. A third example is a set of instructions on a computer-usable medium, or resident in a computer system, for executing methods of the present invention.

Abstract: A computer implemented method and system for simulating strategic planning and operations uses an operations control language (OCL) which has the characteristics of: (a) a target expression, (b) a condition expression, (c) an integer hierarchical priority level, (d) at least one penalty expression, and (e) a value expression. The OCL is a high level programming language for describing operating policies for simulation models, such as those used in water resources management. The OCL of the invention is written into a simple text file. The OCL has syntax, keywords and Boolean and arithmetic operators.

Abstract: A method of inverting events that have been picked from a depth-migrated seismic trace, wherein a collection of traces is determined by depth migration prior to addition, the traces reflecting vertically below, a given surface point, and processing is applied to said collection of traces in order to select a velocity field parameterization which optimizes the alignment of points which are migrated from said collection of traces.

Abstract: The invention relates to a method of performing channel simulation on a radio frequency signal and to a channel simulator for implementing the method. In the solution, the total band reserved for the signal to be applied to channel simulator units is divided into at least two sub-bands. Channel simulation is performed on signals corresponding to each sub-band in the channel simulator units. Finally, the signals simulated in the different sub-bands are combined to form a total band signal in a combiner after channel simulation.

Abstract: A method for training a probabilistic neural network to map seismic attributes or similar quantities.

Abstract: Methods of characterizing subsurface conditions in a selected geographic region previously associated as a whole with a specific subsurface material characteristic reference profile such as from a USDA-NRCS soil survey. The method includes deploying a sensing tool at selected positions within the geographic region to determine a depth-referenced subsurface material characteristic such as soil type or strata, comparing the determined subsurface material characteristic to the subsurface material characteristic reference profile associated with the geographic region to determine a correlation between the subsurface material characteristic reference profile and the depth-referenced subsurface material characteristic, and then deciding whether to deploy the tool at another position, and at what optimum position to deploy the tool, by considering the correlation.

Abstract: A method and apparatus for modeling physical, chemical and sundry conceptual processes is taught. A family of multi, state dynamical systems are used to solve the differential equations that define these processes. Differential bases functions are generated from the evolving states of cellular automata. The use of the differential basis functions greatly simplifies the modeling process. The present invention avoids the use of millions of computational cells as required by the prior art.

Abstract: A system and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources is disclosed. Propagating wave electromagnetic sensors monitor excitation sources in sound producing systems, such as machines, musical instruments, and various other structures. Acoustical output from these sound producing systems is also monitored. From such information, a transfer function characterizing the sound producing system is generated. From the transfer function, acoustical output from the sound producing system may be synthesized or canceled. The methods disclosed enable accurate calculation of matched transfer functions relating specific excitations to specific acoustical outputs. Knowledge of such signals and functions can be used to effect various sound replication, sound source identification, and sound cancellation applications.

Abstract: Methods and an apparatus for determining a radiation dosage received by a product being exposed to radiation in an irradiator cell through a computer simulation are provided. One exemplary method includes a computer simulation for determining radiation dosages received by a product to be passed along a radiation cell, where the product is to be stationary at a set number of locations within the cell is provided. The method initiates with a point on the product being defined. Then, pre-calculated lengths between the point on the product and the radiation source at each of the set of locations in the cell are identified. Next, a dosage of radiation to be received by the point on the product at each location is calculated using the pre-calculated lengths.

Abstract: Time lapse seismic measurements of a laminated reservoir including sands and shales are processed to determine changes in the laminated reservoir. An initial petrophysical model is obtained at a wellbore from measurements made with a multicomponent resistivity logging tool. Changes in the amplitude versus offset behavior of the reflections from the top of the reservoir are indicative of changes in fluid saturation and/or formation pressure.

Abstract: A method for determining alteration of a region of an earth formation surrounding an earth borehole, comprising the steps of providing a logging device that is moveable through the borehole; transmitting sonic energy into the formation and receiving, at a plurality of transmitter-to-receiver spacings, sonic energy that has traveled through the formation, and producing signals representative of the received sonic energy for the plurality of transmitter-to-receiver spacings; determining sonic transit times and differential transit times for the respective transmitter-to-receiver spacings; deriving a test statistic from the differential transit times; and determining the presence of alteration of a region of the formations from the test statistic. An associated apparatus for carrying out the method is also described.

Abstract: A phase-locked loop (PLL) employs a ring oscillator for the voltage-controlled oscillator (VCO), and the ring oscillator comprises an odd number of inverting stages operating at a given frequency. The frequency of the ring oscillator is determined by the delay through each stage and the number of stages. The output signal of each stage has a phase determined by the number of stages, and each stage provides its output signal with a different phase. The VCO of the PLL selects phases of the ring oscillator to clock the counter of the feedback divider of the PLL. Each phase is selected by a multiplexer (mux) under the control of a finite state machine that monitors the output of the counter. When the counter completes a full count cycle on one phase of the ring oscillator, the finite state machine selects a different phase of the ring oscillator to clock the counter for the next count cycle.

Abstract: A system and method for attenuating noise in vibroseis data acquisition. In particular, according to the invention, several preferred methods are discloses that are particularly useful for attenuating noise in seismic data acquired by slip sweep vibroseis techniques. The techniques disclosed involve band-splitting in the time-frequency domain using mirror-filtering, such as a quadrature mirror filter. A noise estimate is made according to which the data is normalized and summed. The time frequency data then reconstructed and transformed back into time domain for further processing.

Abstract: A method of numerical simulation of fluid flow past a body. The physics of stationary flow is formulated in terms of a potential functional of at most four scalar fields: three Clebsch scalar fields and a density field. The physics of non-stationary flow is formulated in terms of an action that includes an action integral of a Lagrangian functional of the same four scalar fields and an initial and a final integral of a function of the same four scalar fields. The values of the fields are varied to extremize the potential functional or the action, under the constraint of appropriate boundary conditions. Potential functionals and Lagrangian functionals for compressible and incompressible flows with zero velocity normal to the surface of the body, and for potential flows, are described.

Abstract: A method provides for locating and measuring mechanical damage in rock surrounding a borehole by detecting one or both of reductions in ultrasonic compressional wave velocity in the rock as a function of azimuth, and by detecting focused acoustic energy in the rock from local increases in ultrasonic compressional wave amplitude resulting from velocity gradients. A first preferred embodiment uses a combination of azimuthal ultrasonic compressional wave velocity data and azimuthal ultrasonic compressional wave energy data. A second embodiment uses azimuthal ultrasonic compressional wave velocity data and omni-directional sonic velocity data, with a comparison test or a curve fitting test. A third embodiment uses azimuthal ultrasonic compressional wave energy data.

Abstract: A method for displaying the results of predicted wireless communication system performance as a three-dimensional region of fluctuating elevation and/or color within a three-dimensional computer drawing database consisting of one or more multi-level buildings, terrain, flora, and additional static and dynamic obstacles (e.g., automobiles, people, filing cabinets, etc.). The method combines computerized organization, database fusion, and site-specific performance prediction models. The method enables a design engineer to visualize the performance of any wireless communication system as a three-dimensional region of fluctuating elevation, color, or other aesthetic characteristics with fully selectable display parameters, overlaid with the three-dimensional site-specific computer model for which the performance prediction was carried out.

Abstract: Solving simultaneous equations of the moment method defining relationships between a mutual impedence between elements of an electronic apparatus, a wave source, and an electric current flowing in each element so as to simulate an electric current, provided with a unit for calculating the mutual impedance at a sampling frequency and calculating approximation coefficients, when expressing the mutual impedance by approximation expressions in terms of exponents and exponent powers, from the calculated values and sampling frequency; a unit for forming the simultaneous differential equations by setting the approximation coefficients and initial value with respect to the simultaneous differential equations derived by performing a Fourier transform on the simultaneous equations of the moment method in which the approximation expressions are substituted; and a unit for calculating the electric current in the time domain flowing through the specified element by solving the simultaneous differential equations formed.

Abstract: A process for obtaining accurate DC convergence in a DC phase of a circuit simulation program for models of field effect transistors (FETs) on a silicon-on-insulator (SOI) substrate. The process comprises running iterations of the DC phase of the circuit simulation program such that error criteria are satisfied, wherein the pseudo-time step changes at each iteration until it reaches a value such that a desired current value is achieved. DC convergence is also achieved by reducing the magnitude of the capacitive and/or charge elements connected to the floating body regions of the field effect transistors on the silicon-on-insulator substrate model during the DC phase to achieve a desired current value.