Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F30/00—Computer-aided design [CAD]
  • G06F30/20—Design optimisation, verification or simulation
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F2111/00—Details relating to CAD techniques
  • G06F2111/10—Numerical modelling

Definitions

• the invention relates to the computer simulation (or modeling) of the temporal evolution of media objects of physical phenomena, such as liquid, gaseous, solid, particulate and similar media.
• the modeling of the interactive phenomenological animation of a virtual reality medium is a particularly difficult task, especially when the dimensions of the medium are important and when it must be done in time. real.
• the invention therefore aims to improve the situation.
• a software for object simulation of the joint evolution of at least some of the activated objects comprising first so-called “enaction” objects defining spatiotemporal autonomous entities each representative of a physical phenomenon and interacting, when activated, within a multi-agent system (SMA) via second so-called “state” objects defining interaction mediators providing spatio-temporal topological support constituting a virtual environment representative of the medium simulated and making it possible to locate interactions between entities in space and in time (or spatio-temporal), and
• a simulation manager capable of sequentially working on a selection of enaction objects, and activating each enaction object once during each sequence, in an order varying at least partially randomly in a manner; sequence to another, so as to dynamically evolve sequence after sequence the spatio-temporal interactions between enaction objects.
• the device according to the invention therefore operates according to an asynchronous mode, since the respective states of the activated objects vary one after the other within each sequence, taking into account the respective states of the other activated objects, and chaotic, because the processing order of each activated object varies randomly from one sequence to another. It is also possible to activate or delete at any time (that is to say in real time) one or more objects, in order to modify the working conditions and / or the simulated system without having to start all over again. simulation, which gives the device a real interactive character.
• the simulation software may also include enaction objects that define instruments constituting autonomous entities for measuring effects on selected interaction mediators of at least selected physical phenomena (represented by the features) to enable the observation of these physical phenomena in selected places in the middle.
• Each entity can be defined by first, second and third active objects arranged so as to respectively exercise a first activity intended to create a topology element consisting of at least one interaction mediator, a second an activity for assigning properties to each topology element located in an influence domain of its entity, and a third activity for modifying the behavior of its entity according to the properties of the topology element that it has created, perceived within the milieu and attributed by all the entities that constituted the milieu.
• each autonomous entity (or enaction object) is preferably associated with an adaptable parameterized behavior model making it possible to define a region of the environment where the properties of the topology element that it has created must be perceived, and every moment in which these properties are to be perceived.
• each perception moment is defined outside two successive temporal validity domains during which the behavior model of the entity concerned does not require a new perception of the properties of the topology element that it has created to remain physically correct.
• time domains are preferentially spaced periodically according to a chosen frequency specific to the entity concerned.
• the simulation software may include a scheduler capable of operating either in a real-time mode, in which it operates according to a chosen frequency, or in a virtual time mode, in which it operates periodically but for periods of time. variables from one period to another.
• FIG. 1 schematically illustrates an exemplary representation of a phenomenological animation in the form of an organization of autonomous entities
• FIG. 2 illustrates in the form of a UML diagram an example of a three-level architecture representative of the interactive animation of a liquid medium such as the sea, according to the invention
• FIG. 3 very schematically illustrates an exemplary representation of autonomous physical entities within a liquid medium such as a portion of a heterogeneous water plane
• FIG. 4 very schematically illustrates an example; creating a spatio-temporal structure of a liquid medium such as a heterogeneous water body by three independent physical entities, and
• FIG. 5 very schematically illustrates, in the form of functional blocks, a computer equipped with an exemplary embodiment of a simulation device according to the invention.
• the attached drawings may not only serve to complete the invention, but also contribute to its definition, if any.
• the invention relates to a device D dedicated to the simulation of interactive phenomenological animation of a heterogeneous medium in virtual reality.
• the medium is a body of water, and more specifically a portion of sea.
• the invention relates to any heterogeneous medium obj and to physical phenomena inducing movements, including on the (sub) atomic or particulate scale. Therefore, the invention applies to liquid media and especially to water bodies, such as the sea, rivers (rivers and streams), lakes and hull basins, solid environments, especially for the analysis of the resistance of materials, and the gaseous media, such as the atmosphere or space.
• the invention applies to situations in which a heterogeneous medium is the object of a combination (or superposition) of physical phenomena of different natures.
• the invention relates, for example, to electromagnetic or acoustic wave phenomena, and in particular to electromagnetic or acoustic waves (action and compatibility) and electromagnetic radiation.
• the device D according to the invention makes it possible, in its application to the sea, to bring together the maritime, oceanographic and infographic points of view, so that the maritime simulation has a meaning for the sailors and remains physically credible to the oceanographers.
• localized phenomena is understood here to mean physical phenomena such as a wave group, a breaking wave, an interaction between at least two wave groups, an interaction between a wave group and a wave, an interaction between a group of waves wave and wind, an interaction between a wave group and a current, or an interaction between a wave group and a depth.
• Each modeled phenomenon corresponds to at least one physical model that depends on at least one parameter. It is important to note that each physical phenomenon is modeled independently of other physical models.
• the device D according to the invention is designed to take account simultaneously for a heterogeneous water body (here a portion of sea, for example about ten square kilometers) of the local effects of physical phenomena, such as breaks, winds, currents or bathymetry, on groups of waves of all wavelengths.
• a heterogeneous water body here a portion of sea, for example about ten square kilometers
• physical phenomena such as breaks, winds, currents or bathymetry
• the device D uses first objects called "d 'enaction' defining autonomous entities modeled from theoretical and experimental results of physical oceanography and interacting in a multi-agent system without passing through a mesh either predefined or adaptive.
• autonomous entity an entity (or enaction object) such as a Wave Group, an Active Surf, a Passive Surf, a Synoptic Wind, a Local Wind, a Shoal or a Current.
• the oceanographic models of these physical entities and their interactions are, for example, described in detail in the document by M. Parentho ⁇ n and al. IPAS: Interactive Phenomenological Animation of the Sea, International Journal of Offshore and Polar Engineering, 2004, whose content is hereby incorporated by reference, they will not be described in detail.
• each enaction object (or autonomous entity) is arranged to operate according to an active approach of perception by specifying "where" and “when” it needs to observe “what”.
• the activities of the different entities hereinafter called “aisthesis”, structure the spatio-temporal and semantic topology of the environment (here the sea) intended to mediate interaction (through the particles of water which constitute it).
• Enaction object is more precisely defined in the Thesis of the University of Western Brittany of M. Parentho ⁇ n, whose title is "Phenomenological Animation of the Sea”.
• visualization of the medium is only an option offered by the device D according to the invention. This results from the fact that a user (or observer) is placed at the same conceptual level as the entities that carry out the animation, and thus constitutes an autonomous entity.
• the animation of the environment can be done independently of its visualization.
• the visualization of the sea must specify "where" and “when” to observe “what” according to the phenomena that wants to see the user (or observer) and where he wants to see them, and thus participates in the creation of the spatio structure -temporal and semantic of the medium.
• a user such as for example a sailor, generally determines his actions according to certain phenomena that he has observed and / or that he knows, either by experience or by means of information received or read.
• the phenomenological animation of the sea is a multi-model system in which each model results from the description of a phenomenon considered independently of other phenomena.
• Each model describing a phenomenon must therefore verify a principle of autonomy. In other words, each phenomenon must be "objectified” (or “reified”) into an autonomous entity with sensorimotor and decision-making capabilities of its own.
• SMA Multi-Agent System
• each agent is an autonomous entity that has sensorimotor capabilities, and communicates with the environment determined by the other agents.
• Agents are located in the environment in which they evolve according to their own patterns of behavior, which define their perception, action, and decision capabilities based on internal characteristics and their interactions with the environment.
• the interactions are mediated by a medium whose spatio-temporal structure is not predefined, but is built as and by the entities themselves.
• Each entity contributes to the structure by creating an element of topology, according to the needs necessary for its self-adaptation.
• the set consisting of the different autonomous entities, then assigns properties to each topology element associated with each entity, and each entity adapts its own behavior to the properties that it actually perceives in the environment by means of its associated topology element.
• each entity or enaction object
• Each entity is defined by a triplet of active objects whose respective activities (or methods) reflect what it seeks to perceive, its action on the world to be perceived by the set of all the entities, and what it becomes in view of the properties actually perceived in the said world.
• each autonomous entity (a, b, c, d) is arranged so as to structure the medium by inserting a spatio-temporal topology element.
• This aptitude of the entities for the structuring of the medium constitutes their first role (or activity), hereinafter called "aisthesis”.
• the global topology of the environment is defined by the union of the spatio-temporal topology elements of the set of entities.
• Each autonomous entity (a, b, c, d) is furthermore arranged so as to act according to its own know-how on the global topology by attributing properties to it. This ability of entities to assign to the middle of properties constitutes their second role (or activity), hereinafter called "praxis".
• Each autonomous entity (a, b, c, d) is finally arranged in such a way as to adapt its own behavior according to the perceived characteristics of the medium, that is to say the properties of the topological element that it has previously created. which are determined by the set of entities.
• This ability of entities to behavioral adaptation constitutes their third role (or activity), hereinafter referred to as "poiésis”.
• the medium serves as a mediator of interaction between the different autonomous entities of the organization, which can only live if the autonomous entities that constitute it activate their different roles of perceptual prediction, action on the environment and adaptation to the environment. .
• FIG. 2 describes, by means of a UML diagram, the architecture enabling the simulation device D, according to the invention, to implement the organization presented above with reference to FIG. 1, in the application at sea state.
• a first level Nl is dedicated to the scheduling of active object activities.
• a second level N2 is dedicated to the virtual environment consisting of physical entities presenting the natural phenomena whose interactions are mediated by the medium.
• a third level N3 is dedicated to the specification of the virtual environment to the animation of the environment (here the sea).
• the first level N1 also called simulator, comprises a scheduler (or sequencer, or “scheduler") responsible for managing activities that call methods of objects implanted in a module Ml and which will be discussed later.
• scheduler or sequencer, or "scheduler”
• the scheduler implements, as will be seen in more detail below, a process of iterations in turn making live the active objects (or entities) constituting the virtual environment.
• the scheduler performs asynchronous iterations, to respect the autonomy of the entities, and chaotic to not introduce bias in the simulation.
• the second level N2 is dedicated to natural phenomena and their observation. It makes it possible to constitute the virtual environment from autonomous entities located in the 3D space and in time.
• the virtual environment feeds the module Ml containing the object methods.
• Autonomous entities or enaction objects
• the set of interaction mediators forms what can be called the medium.
• the purpose of the virtual environment is to solve the topological problems relating to the location of entities and interaction mediators, in order to answer the question "who does where and when?".
• the natural phenomena that we seek to simulate are chosified (or reified) into physical entities located in the virtual environment and that ensure the physical coherence of the simulation of natural phenomena.
• the observation of natural phenomena is mediated by a measuring instrument fed by a viewer implanted in the third level N3.
• each physical entity or enaction object has three particular methods (or activities): the aisthesis for creating interaction mediators gathered in one topology element, the praxis for giving properties to each topology element located in its neighborhood of influence, and the pooiisis to modify the behavior of an entity or to create new entities.
• instruments may also define instruments to observe phenomena by measuring their effects on interaction mediators, the interaction then being that of the model with the user who can be a mere observer, a sensorially immersed actor, or a modeller by the mediation of the programming language.
• instruments can have the three methods presented above, but most often their praxis can be neglected.
• the third level N3 is dedicated to the specification of the virtual environment to the animation of the medium (here the sea). It comprises, firstly, an M2 module defining the different types of physical entities (Wave Group, Surf, Current, Local Wind, Bathymetry, Synoptic (or Wind Synoptic), etc.), a second part, a module M3 defining the water particles and the associated properties (dynamic position, mask, normal, wind, current, depth, turbulence, etc.), a third part, a module M4 defining the mediation medium that is here the sea, and a fourth part the viewer which is a particular entity composed of a large number of specific water particles forming a mesh of the surface of the sea to be observed and to be updated according to a chosen frequency, preferably greater than or equal to 10 Hz, by the physical entities constituting the virtual environment, and in particular by the groups of waves, and texture as a function of the groups of waves, local surges and winds, via the instrument of e measure.
• an M2 module defining the different types of physical entities
• this third level N3 which is adapted according to the types of enaction objects (or entities), state objects and interaction mediators concerned.
• the Groups, the Breaks, the Winds, the Currents and the Bathymetry ensure the oceanographic coherence of the phenomena and their interactions via the properties of the Water Particles (position, normal, wind, current, depth, turbulence, etc.).
• each autonomous physical entity comes from the reification of a physical phenomenon (observed by sailors). As schematically illustrated in Figure 3, these autonomous entities are located in the virtual environment and have their own behaviors.
• the behavior model of an autonomous entity is associated with a prediction capability, that is, a temporal validity domain in which the behavior of the entity does not require a new perception of properties. from the middle to stay physically correct.
• the knowledge of the temporal domain in which the autonomous entity can evolve in autonomy makes it possible to determine the frequency of the acts of perception of this autonomous entity.
• Each entity thus knows that it will need a given type of localized information in so much time and place, relative to its prediction.
• Each "Wave group” entity is for example controlled by a wave train giving it mean characteristics (finite extension of the Gaussian envelope in length and width, group velocity, number of waves, wavelength, period , horizontal ridge profile, phase velocity, age of the group), plus local phase and amplitude disturbances attached to the crests of the waves flowing through it, in order to model the nonlinear aspects of the waves.
• the wave train may be a 2D Morlet wavelet whose envelope moves at the group velocity and whose phase of the sinusoidal layer progresses at the phase velocity.
• the Morlet 2D wavelet is one of the mathematical tools used by the simulation software (which will be discussed later with reference to FIG. 5) and in particular by its interaction mediators (water particles).
• the Wave Group is sensitive to other autonomous entities such as Breaks, Currents, Winds, Bathymetry and other Wave Groups.
• Wave Groups Since a Wave Group must be able to perform action transfers to the Breaks, its predictive domain can not exceed the lifetime of a Surf (the other phenomena being observable at a lower frequency).
• the good marine or physical sense making it possible to estimate at approximately one second the minimum life span of wave surges of more than one meter of wavelength, it is possible for example to fix at one second the capacity of anticipation of the model.
• Wave groups In this case, the Wave Groups are responsible for asynchronously activating their perceptual behavior at a frequency of 1 Hz, in order to know the evolution of the effects of the Surf, Wind, Currents and Bathymetry on the properties of the middle to perceive.
• Paisthesis of each Wave Group is responsible for creating each second a topology element, for example consisting of five points distributed in its envelope (defining its spatial extension), whose position is anticipated by one second.
• Each deferment preferably occupies a surface of the observed body of water, which is composed of contiguous elementary zones, for example 1 m 2 .
• Each zone may be associated with an active or passive phase of the Surf, depending on whether or not it belongs to the active front of this Surf.
• a process of manufacture of foam and turbulence can be implemented according to the local activity of the Surf (the word “activity” must here be understood in its physical sense of "rate of production” and not not in the computer sense), while in each passive zone a process of relaxation of the foam and turbulence can be implemented.
• the propagation of the active front of a Surf is a very dynamic process, influenced by the Waves and the Winds, one can for example update the activity of the active zones (here of 1 m 2 ) at least twice a second.
• the dissipation of the moss and turbulence is much easier to predict (because it is sensitive only to the currents that transport them and to the winds that direct them in trails of foam), and the evolution of the winds. and Currents being quite slow, we can for example update the dissipation every 10 seconds.
• the Breaks activate their perceptual behavior at a frequency of 2 Hz on their active fronts in order to know the effects of the groups (waves) and the Winds, and at a frequency of 0.1 Hz for their relaxation zones so to know the effects of Currents and Winds.
• the aisthesis of each Surf, participating in the virtual environment is thus responsible for creating, on the one hand every half-second for its active front, a topology element consisting of particles of the active zones in order to to change the activity and to determine the end of the activity of each active zone, to which are added particles located in front of the active front and anticipating the spread of the surf; and on the other hand every ten seconds additional particles in the passive areas.
• Synoptic or Wind Synoptic
• Local Winds evolve continuously over time in force and / or in direction, but the influence of the Synoptic is global on the entirety of the observed body of water, on which it can create Wave groups, while the local Wind does not participate in wave group creation and has a finite extension envelope that can move and transform itself.
• These entities preferably modeled by descriptive models that are insensitive to the environment, have no real need for perception. This is also the case, as a first approximation, of the Currents and the Bathymetry because their parameters evolve exclusively with time
• the physical entities thus participate in the creation of the spatio-temporal structure of the environment and evolve there autonomously between two acts of perception.
• An act of perception is here characterized by a perceptive anticipation ("where and when will I need what?") That precedes the observation of the properties of the environment, from which the entity concerned adapts its behavior.
• the interactions between the entities are then mediated by the medium they created and to which each entity contributes to give properties.
• the virtual sea computing model is a heterogeneous multi-agent system (or SMA) composed of interacting physical entities.
• SMA multi-agent system
• Each autonomous entity is located in the virtual environment and has its own behavior, resulting from the reification of a physical phenomenon observed by the sailors (Wave group (s), Surf (s), (Wind) Synoptic, Winds Local, Shoals, Currents, etc.).
• the behavior model of each entity is characterized by the predictive ability of what should ideally be the behavior of the entity, which corresponds to the frequency with which the entity must perceive its environment to adapt to the changes in the behavior of the entity. middle.
• the physical entities thus ensure the oceanographic coherence of the phenomena by interactions based on the characteristics of the water particles (interaction mediators). These characteristics include the reference position, the dynamic position (updated by the physical entity Wave group), the normal (updated by the physical entity Wave group), the wind (set to day by the physical entities Synoptic Wind and Local Winds), the current (updated by the current physical entity), the depth (updated by the physical entity Bathymetry) and the thickness of the turbulence (updated by the physical entity Surf).
• the Water Particle is the interaction mediator for the phenomenological simulation of the water body (here the sea). It constitutes a topological support, called reference position in space - time. This reference position constitutes a point M (O 3 X 0 ) of the space (where X 0 is a vector), associated with a given time t 0 . These are the reference positions in space-time that are specified by the activities of active perception of the autonomous entities during the creation of the spatio ⁇ temporal structure of the environment (the Sea).
• the Sea knowing the Water Particles, arranges them as and when they are created in ascending order of the times t 0 during which the entities anticipate the observation of the properties.
• An entity acts on a temporally located particle at time t Q only if this instant is in the domain of prediction validity of the model of the entity, that is to say between two perceptive acts.
• the entity that creates this water particle specifies what type (s) of property it needs using a mask.
• the physical entities whose praxis influences a type of property are made to act, which makes it possible to simplify the complexity of the resolution of the topological relations between the entities and the interaction mediators by a first semantic rather than geometric selection.
• a water particle can have many properties, such as its dynamic position around the reference position M (O 5 X 0 ), its speed relative to the sea, its normal to the sea surface, the list of Groups of waves that influence it, the Wind, the Current, the Depth, the thickness of the turbulences, and the list of waves and associated activities.
• wave group entities may act in a particulate pattern, possibly inspired by that described in the FJ document. Gerstner
• each water particle is located on the sea and in time by a reference position and has properties updated according to the praxis of the physical entities that influence it.
• the activity of praxis is determined by the environment Mer, which knows the positions of the Water Particles and the entities at each moment, by solving the neighborhood relations between the said Water Particles and entities.
• These water particles then serve as interaction mediators because their properties, derived from the influence of all the entities present, are used by each physical entity to adapt its own behavior.
• the set of Water Particles is created by the entities as they interact. This set is in perpetual evolution over time, both by the number of water particles and by their positions in space, and forms the environment in which the entities interact.
• FIG. 4 shows a schematic example of the creation of a spatio-temporal structure of the sea medium by three entities (two wave groups and a breakup), by means of their aisthesis.
• the constitutive water particles of the medium are represented by circles with patterns.
• the entity Surf (deferl (t 0 )) provides for needing, on the one hand, in 0.5 seconds (ie t o + O, 5) of Particle properties. of water on its active front ZA and in front of it in its direction of propagation, and secondly in 10 seconds (ie t o + l ⁇ ) of properties of the medium in its passive zone ZP (materialized by small points).
• the first wave group (group ⁇ t j )) predicts that it needs properties at the position (Gl_estim) where it is supposed to be in 1 second (ie tj + 1). He then creates five particles of water for the moment X x + ⁇ .
• the second Wave Group (group_2 (t 2 )) predicts that it needs properties at the position (G2_estim) where it is supposed to to be within 1 second (ie t 2 + l). He then creates five water particles for the moment t 2 + l.
• the device according to the invention D makes it possible to change physical phenomena characterizing a medium (here the sea) without necessarily having to look at said medium.
• the device D makes it possible to simulate some of the physical phenomena inherent in the surface of the sea independently of their visualization, of course except for the fact that the modeled phenomena depend on what we are trying to perceive.
• the visualization of the environment indeed requires to consider the user as one of the active elements of the model.
• the Viewer must therefore be an autonomous entity participating in the organization, immersed in the virtual environment through the mediation of a man / machine interface. Therefore, the user must specify the spatio-temporal structure of the environment he wants to observe certain properties ("where and when I look what?"). According to what he perceives, the user decides on the next places where he wishes to observe selected phenomena. This approach is the same as that implemented by the autonomous entities populating the virtual environment, which consists of performing an active perception (or aisthesis).
• Minimal immersion is visual and rendered by the image of a virtual camera, for example.
• An interaction with the virtual camera can be envisaged, for example by means of the control keyboard and / or the mouse.
• the camera can be attached to a fixed or moving object, such as a boat, on which an observer is possibly located (or immersed).
• the animation (here of the surface of the Sea) is done according to a perception model defined by a frequency higher than 10 Hz and a textured geometry, structured in a mesh whose points are distributed respecting a certain distribution of spatial probability.
• the Sea can be instrumented by the Visualizer entity (of the third level N3 of the architecture of Figure 2). As indicated previously, the Visualizer entity (of the third level N3 of the architecture of Figure 2).
• Visualizer is indeed in charge of structuring the environment (here the Sea) according to the perception model and to recover the relevant properties for the visualization of the surface of the Sea.
• the projection of the properties observed by the Visualizer entity then makes it possible to reveal the Sea on the display monitor of the man / machine interface.
• a Viewer entity represents a couple (geometry, camera). It is assumed in the following that the number of points constituting the geometry is fixed (it depends on the power of the computer equipment supporting the simulation device D), and that the topology of their respective neighborhoods is conserved over time.
• the positions of the points of the geometry are preferentially generated respecting a probability distribution fixed by the perception model associated with the Visualizer.
• the mesh is for example defined according to a so-called static Delaunay triangulation performed during the initialization on positions of the default points. Such a triangulation is notably described in the document by MJ. Castro et al "New progress in anisotropic grid adaptation and viscious inviscid flow simulation," Technical Report 2671, INRIA May 1995.
• the topological structure of the geometry is preferentially static so as not to have to triangulate on the fly. But, one can also consider dynamically changing the grid of the topological structure, at the positions of the points that define it, for example by means of transformations retaining the structural topology other than simple translations, rotations or homothéties. For this purpose, it is possible, for example, to use projections of the type described in the aforementioned document by D. Hinsinger in order to adapt the representation of the details of the movement of the sea to the point of view of the camera.
• the aisthesis activity of the Visualiser consists in structuring the medium (here the Sea) by generating, for example every tenth of a second at least, the element of topology whose Associated water particles have as positions of reference the positions of the points of the grid determined by the perception model of the Visualizer.
• the construction of the image requires the knowledge at each point, a first part of the dynamic position and the normal to reconstruct the surface of the Sea, a second part of the thickness of the turbulence to represent the passive foam, a third part of the activity of the Breakthroughs to allow the regulation of the flow of a system of Water Particles (which is a graphical object which can be very resource-consuming, and which is not this fact instantiated that if its position places it in a zone of perceptual attention specified by the visualizer's perception model), a fourth part of the Wind to allow the parameterization of the divergence of the generator of Water Particles and the texture of the wavelets (for example with a "bump-mapping" of the type described in the document by J.
• the set of Water Particles constituting the topological element of a Visualizer is generally too important for the physical entities that influence the grid to solve the topology problems of their praxis without resorting to a specific method. Since the spatial distribution of reference points is not regular, a simple box-based method is not efficient enough to solve these problems.
• the manufacture of the tree is preferably carried out during the initialization of the geometry, substantially at the same time. that triangulation.
• the Visualizer entity thus makes it possible to give a spatio-temporal structure in the middle (here the Sea), dedicated to the human perception and giving access to the properties necessary for the visualization of the Sea by revelation by means of the display monitor.
• the revelation of the Sea corresponds to the development of the photographs of the praxis of the physical entities that populate it, as taken by the Visualizer entity. This revelation depends mainly on the characteristics of the display monitor graphics card and the fineness of the geometric mesh grain.
• a graphics card supporting, for example, a "Vertex and Pixel Shader” version 2.0, such as the Nvidia GeForce FX card, as well as a working main processor. at 1.4 GHz, such as the Intel Pentium IV processor. Only a few megabytes are then used in RAM by the program, and the initialization (triangulation, etc.) typically takes about fifteen seconds.
• a body of water of about 4 Km 2 can be covered with about 8000 interacting physical entities and the geometric grid can be composed of 6000 points.
• the complexity of the physical simulation of the oceanographic phenomena in interaction is then, from the point of view of the CPU, of the same order of magnitude as that of the animation of the geometric grid.
• FIG. 5 describes an example of a simulation device according to the invention D, of asynchronous and chaotic type, as mentioned above, capable of implementing the architecture presented above with reference to FIG. .
• the device D can be installed in a computer C comprising an operating system
• OS and CPU processing and calculation means suitable for operation in a multi-tasking mode such as that offered by the oRis environment described in particular in the document "Multi-agent systems", pages 499 to 524, RSTI - TSI , 21/2002.
• a multi-tasking environment is particularly well suited to programming by activated objects, for example in C ++ or Java language.
• the multi-task environment oRis is coupled, like the device D which is illustrated, to a compiler (here called “object programming compiler”).
• the oRis environment can be coupled, like the D device that is illustrated, to a C ++ language translator (here called "obj and interpreting interpreter”) in order to improve its efficiency by compiling.
• This interpreter can even be adapted to form an online compiler in which the code executed is an online compiled and dynamically modifiable code.
• Such a multi-task environment, constituting an oRis evolution is known as AReVi.
• the device D comprises a software for simulating the joint evolution of activated objects (here called "general simulator”). More precisely, this simulation software (or general simulator) comprises the (first) so-called enaction objects and the (second) so-called state objects.
• the simulation software (or general simulator) also comprises a simulation manager coupled to state objects and enaction objects (or entities) and arranged to create its own scheduler (or in English "scheduler") to work sequentially on a selection of objects of enaction.
• the simulation manager calculates interactions once the environment (here the Sea), which makes the enaction objects (or entities) live, has solved the topological problems.
• the simulation manager is specifically responsible for activating a single time during each sequence, under the control of the sequencer (or scheduler) it creates for the occasion, each enaction object selected, in an order that varies from at least partially at random from one sequence to another, in order to apply each of its three activities to the current state of each state object that it designates so as to change its state to a new one. current state, or in other words in order to dynamically evolve sequence after sequence the spatio-temporal interactions between entities.
• the user first chooses one or more enaction objects, so that the device D simulates the spatio-temporal evolution of the system. This "pre-activates" each enaction object chosen within the simulation software.
• the simulation manager initializes a sequence counter by setting the counter's value n to 1, and creates a list of enaction objects.
• the simulation manager performs a test to determine if there are still other enaction objects to apply in the enaction object list of the current sequence.
• the simulation manager performs a new selection phase to randomly select one of the remaining enaction objects. As indicated above, it then activates this new selected enaction object and applies each of its activities to the current state of each state object, possibly modified by the activation of the previous enaction object (which can not be used in the current sequence).
• the simulation manager increments the current value n of the sequence counter by one. Of course, it performs a test on the number of sequences to perform. If the number of sequences performed is equal to the maximum number expected, the simulation manager terminates the simulation. On the other hand, if there remains at least one sequence to be performed, the simulation manager performs a new sequence corresponding to an instant T + 1, T + 2, ..., T + n. He then repeats the above operations at each new sequence.
• the duration of the simulation, and therefore the maximum number of sequences performed by the simulation manager depends on the application concerned, or the setting chosen by the user given the application. But, the simulation can be interrupted at any time by the user using a stop instruction transmitted to the simulation software through a man / machine interface of the computer C. It is important to note that simulation interrupted at the request of a user may be resumed later ⁇ ment. It is important to note that the sequencer (or scheduler) can operate in virtual time, or in other words that its operation is not constrained to respect the real time, but each of its iterations represents logically, and not physically, a duration of one millisecond (1 ms). Of course, the sequencer can also operate in real time. In this case, each of its iterations physically lasts a chosen period.
• the user can at any time intervene in a simulation, either in the form of an "avatar" to interact with the object of the simulation, by example the middle, either to add to its selection or to remove from its selection one or more enaction objects.
• the user may also decide to modify at least partially the definition (or structure) of one or more enaction objects. This gives the simulation software great interactivity.
• the invention has many applications in many technical fields, and particularly in the fields of navigation assistance, naval architecture (for example for the behavioral study of a boat or a platform). offshore form, replacing and / or in addition to hull basins), the study of the resistance of materials or wave phenomena (electromagnetic or acoustic).
• naval architecture for example for the behavioral study of a boat or a platform.
• offshore form replacing and / or in addition to hull basins
• the study of the resistance of materials or wave phenomena electromagagnetic or acoustic.
• a possible application is the modeling of the conjugated interactions between a ship, radar waves and the sea in the case of the detection and / or recognition of an object.
• the heterogeneous medium was the subject of physical phenomena of the same nature.
• the invention also relates to applications in which the heterogeneous medium is the object of a combination (or superposition) of physical phenomena of different natures.

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• 2004
  • 2004-06-02 FR FR0405943A patent/FR2871261B1/fr not_active Expired - Fee Related
  • 2004-09-22 EP EP04787412A patent/EP1751682A2/fr not_active Withdrawn
  • 2004-09-22 JP JP2007513992A patent/JP2008502040A/ja active Pending
  • 2004-09-22 WO PCT/FR2004/002384 patent/WO2006003271A2/fr active Application Filing
  • 2004-09-22 US US11/628,001 patent/US20080167847A1/en not_active Abandoned
  • 2004-09-22 CA CA002568258A patent/CA2568258A1/fr not_active Abandoned

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