Abstract: A system, method, apparatus and product for designing, on a display device, a geometric shape is disclosed. The method comprises the steps of displaying an initial set of similarly structured model exemplars on a display device, selecting a chosen set of models from the initial set of similarly structured model exemplars to apply to a model mix, mixing the set of models to form a currently displayed shape, providing on the display device at least one selectable feature for manipulating the currently displayed shape, and applying at least one constraint of the selectable feature to the currently displayed shape to update the currently displayed shape into a new geometric shape design.

Abstract: A method of synthesizing an electrical or electronic architecture of at least one part of a product including electrical wires and electrical and electronic components, such as sensors, actuators, and computing devices. In the method: the geometry of the product, which is divided into different zones, is represented two-dimensionally; routing points for the routing of the electrical wires are positioned in the different zones; connection points are positioned between the different zones; electrical and electronic components are positioned in the zones; a routing is synthesized according to the geometry of the different zones and the positions of the routing points, the connection points, and the components; the routing is assessed and, using the result of the assessment, the positions of the routing points, connection points, and/or electrical and electronic components are altered; and the synthesis and assessment are repeated.

Abstract: The present invention relates to systems and methods of integrating driving simulators, data acquisition systems such as, for example, event data recorders, and/or vehicles, as well as to methods of training or providing instruction to drivers using driving simulators, data acquisition systems and/or vehicles.

Abstract: In a method for training a person while operating a vehicle, the vehicle has a control system for receiving vehicle operating commands from the person for controlling the vehicle. A calculation unit is provided for simulating a state of the vehicle and/or the environment to which the vehicle is subjected, the simulated state being a possible real state of the vehicle and/or the environment which is different from the actual state of the vehicle and/or the environment. The vehicle operating commands and the calculation unit are used for calculating vehicle command signals. The vehicle command signals are used for controlling the vehicle so as to cause the vehicle to respond to the vehicle operating commands in a way that corresponds to the state simulated by the calculation unit instead of the actual state of the vehicle and/or the environment.

Abstract: A model predictive control apparatus includes an initial solution generation section, an abnormality handling section, and an objective function adjustment section. The abnormality handling section performs initial solution generation when it is determined that performed optimization is abnormal. The initial solution generation section generates an initial optimal value of a future time series control input in accordance with an initial objective function, without reference to a candidate value of the time series control input. The objective function adjustment section adjusts the current objective function so that the current objective function varies stepwise with time toward the normal objective function when it is determined that the current objective function is different from the normal objective function.

Abstract: A method is provided for a virtual sensor system. The method may include obtaining data records associated with a plurality of input parameters and at least one output parameter and adjusting values of the input parameters based on autocorrelation of respective input parameters. The method may also include reconfiguring the input parameters based on cross-correlation of respective input parameters relative to the output parameter and establishing a first virtual sensor process model indicative of interrelationships between the adjusted and reconfigured input parameters and the output parameter.

Abstract: The present invention provides a maintenance support system for a construction machine that allows a components maintenance schedule to be accurately established. The system 1 calculates the cumulative load of every component corresponding with the driving and working conditions of the construction machine 3 by means of the load calculation means 13 after simulating the driving and working conditions on the basis of production operating conditions by means of the operation simulation means 12, and forecasts the lifespan of the respective components by means of the lifespan calculation means 14 on the basis of the cumulative load. Hence, a more accurate maintenance schedule can be established in comparison with a case where which component is to be maintained is determined on the basis of only the operating time as in the prior art. The possibility of an unexpected component anomaly occurring at an earlier stage than the predetermined lifespan can therefore be reduced.

Abstract: A process for designing dump bodies which more accurately takes into account field loading/haulage conditions is provided. The process includes gathering data from actual field environments including material density, front, rear and side angles of material repose and corner void information. From this data, a three dimensional model of the load is generated. This three dimensional load model is then used to design the truck body in an iterative process until the volume of the truck body and the distribution of weight of the three dimensional load model on the truck chassis is substantially the same as the desired volume and the distribution of weight on the truck chassis.

Abstract: A method is provided for simulating a vehicle crash on a fuel delivery module of a vehicle. The fuel delivery module (11) has a flange (10) constructed and arranged to be coupled to a fuel tank, a fuel pump (12) for delivering fuel from the tank and through the flange, a reservoir (18) housing the fuel pump, and strut rods (14). Each strut rod has an end coupled to the reservoir or fuel pump and another end coupled to the flange at an interface. The method models a fuel tank associated with the fuel delivery module as a rigid or elastic shell. A solid model of the fuel delivery module is created. The solid model is meshed to create a finite element model. Fluid in the fuel tank is modeled with Lagrangian or arbitrary Lagrangian Eulerian finite elements, or smoothed particle hydrodynamics particles. Solid fluid interactions are added to the meshed solid model.

Abstract: A simulation device for generating an answer to a question inputted thereto. A communication unit is configured to input a selected question associated with a first criterion and a second criterion. A generating unit is configured to generate a copy of a continuously updated environment model. A generating unit is configured to generate a simulation scenario, depending upon the first criterion. A modifying unit is configured to modify the generated simulation scenario. An applying unit is configured to apply the modified generated simulation scenario to the generated copy of the continuously updated environment model. A simulating unit is configured to perform a simulation process in accordance with the second criterion. An answering unit is configured to answer information, depending upon a result of the simulation process.

Abstract: A method of analyzing the vibro-acoustic optimization potential of a structure of vibro-acoustically coupled subsystems having internal and coupling loss factors by means of statistical energy analysis (SEA). The method optimizes the vibro-acoustic behavior of the structure.

Abstract: A method for setting up setup parameters for a machine to perform a time-constraint task over a fixed course. The method may include establishing a process model indicative of interrelationships between performance parameters of the machine and a plurality of setup parameters of the machine based on data records generated by a computer system. The performance parameters may be associated with constraint parameters of the machine and the setup parameters are associated with condition parameters of the fixed course. The method may also include obtaining values of the condition parameters; adjusting the process model to generate a desired set of values of the setup parameters corresponding to a desired set of values of the performance parameters of the race car based on the values of condition parameters; and presenting the desired set of values setup parameters.

Abstract: In a method of numerical modelling of the operation of a gas turbine engine, randomly chosen numerical modifications are made to values within the model, to represent a disturbance for triggering rotating stall. This results in a faster onset of rotating stall within the model, reducing the computational effort required to achieve this.

Abstract: A computer implemented method, apparatus and computer usable program product for mapping a position of a physical point on a digital model. The method comprises receiving sensor data for the physical point from a sensor unit and correlating a position of the physical point to the digital model. The computer implemented method calculates an alignment probability for the correlated position and then compares the calculated value to a stored threshold value. If the alignment probability for the correlated position does exceed the predetermined threshold probability, an aligned position is formed. An aligned position of the physical point is stored relative to the digital model, responsive to a store map location command.

Abstract: System, method and computer product for baseline modeling a product or process. A service database contains process data. A preprocessor processes the data into a predetermined format. A baseline modeling component builds a baseline model from the preprocessed data, wherein the baseline model relates process performance variables as a function of process operating conditions.

Abstract: A method for optimizing data gathering, is provided wherein the method comprising the steps of designing a first system test comprising two or more maneuvers, compiling a one or more data variable for each of the two or more maneuvers from the first system test, pooling each data variable from each maneuvers into a first set of data, removing a first maneuver's data variables from the pooled first set of data, comparing the first maneuver's data variables against the first set of data with the first maneuver's data variables removed, and determining whether to perform the first maneuver based on whether the maneuver provided new data.

Abstract: A model-based estimation of mass airflow is provided which provides an accurate estimation of mass airflow without introducing undesirable time delays characteristic of filtered mass airflow signals.

Abstract: A method for stimulating wheel electronics systems of single tires of at least one tire group in a motor vehicle. The wheel electronics systems are stimulated with a low frequency trigger signal, as follows: a trigger signal is emitted from an LF trigger to the wheel electronics systems of the relevant tire group at a variably adjustable first transmission field strength. Radio frequency signals are transmitted from those wheel-side wheel electronics systems, at which a sufficiently high transmission field strength of the trigger signal has arrived containing an item of trigger information, to a vehicle-side receiving unit. A determination is made of the number of RF signals received by the vehicle-side receiving unit, each containing one item of trigger information.

Abstract: A method for modeling a tire model used for a computer simulation of a pneumatic tire with a toroidal main body and a circumferentially extending tread pattern formed thereon, comprises a step for setting a three-dimensional main body model by dividing the main body by N (N is an integer not less than 2) equally in a circumferential direction of the tire using a finite number of elements a step for setting a three-dimensional pattern model by dividing the tread pattern by M (M is an integer greater than N) equally in the circumferential direction of the tire using a finite number of elements to make, a step for coupling the pattern model with the main body model while aligning each tire rotation axis to make a three-dimensional tire model, and a correcting step for moving nodal points existing on a radially outer surface of the pattern model such that a thickness of the pattern model measured from a radially outer surface of the main body model in a normal direction becomes constant.

Abstract: Methods and systems for converting simulation data from a first format into a second format thereby allowing the converted data to be overlaid onto imagery data. A simulator, such as OneSAF, generates the simulation data in a first format. An adapter converts the simulation data from the first format into a second format. A imagery system, such as Google Earth, then displays the converted simulation data in the second format over imagery data for the corresponding location.

Abstract: A tire tread, comprising a tread pattern formed of groups of motifs arranged, in the transverse direction, in a number M of distributions at least equal to two and of average width Li, Lj, the total of the widths Li, Lj being at least equal to 80% of the width L of the tread, each distribution of groups of motifs being formed by a succession of a plurality of groups, at least two of said groups of motifs of the distribution in question having different longitudinal lengths, the ratio Ri between the longitudinal length of the smallest group of motifs and the largest group of motifs being strictly less than one, this tread being characterized in that for at least two distributions comprising respectively Ni and Nj motifs, with Ni<Nj, the following relationships are satisfied: 0.20?Tij?0.50, 0.60?Rpg?0.

Abstract: A system and method for interactive design of a product includes the steps of identifying an ideal design solution by identifying an unnecessary design parameter having a predetermined significant influence on a variable design response and fixing a predetermined nominal value of the identified unnecessary design parameter at which the variable design response is a minimum and the product design is an uncoupled design or a decoupled design. The method also includes the steps of selecting a most robust ideal design solution from the identified ideal design solution that is the most uncoupled design or the most decoupled design. The method further includes the steps of optimizing the most robust ideal design solution to obtain a pareto-optimal design solution for use in the design of the product that includes a design parameter having an independent design response.

Abstract: A system and methodology for controlling structural type integration to major fittings requires creating a geometrical set of objects identified here as basic starting geometry which consist of external references and relationships to a main component structure. Structural interface detail characteristics and hardware components are identified that make up a major fitting integration connection between the main component structure and a second component structure. Parametric sets and associated geometrical sets containing sketches and geometry objects are identified and created, the parametric sets and associated geometrical sets being associated to a particular hardware component used in the integration connection between the main component structure and the second component structure and used to defined and control the integration connection between the main component structure and the second component structure with respect to fit, form and function.

Abstract: A method for designing a flight vehicle includes determining a preferred aerodynamic shape of a structure of the vehicle; modifying the preferred aerodynamic shape based upon constraints; and determining, using aerodynamic computational fluid dynamics, limit loading conditions for the modified aerodynamic shape. A computer-implemented system for designing a flight vehicle includes at least one computer operable to determine a preferred aerodynamic shape of a structure of the vehicle; modify the preferred aerodynamic shape based upon constraints; and determine, using aerodynamic computational fluid dynamics, limit loading conditions for the modified aerodynamic shape.

Abstract: System, method and computer product for baseline modeling a product or process. A service database contains process data. A preprocessor processes the data into a predetermined format. A baseline modeling component builds a baseline model from the preprocessed data, wherein the baseline model relates process performance variables as a function of process operating conditions.

Abstract: A method of phasing u-joints of a steering shaft assembly in a three shaft, two u-joint arrangement involves inputting steering shaft assembly coordinates to a first spreadsheet, generating a computer-aided design image of the steering shaft assembly based on the steering shaft assembly coordinates, performing kinematics calculations of the steering shaft assembly using the computer-aided design image, exporting kinematics calculation results to a second spreadsheet, graphing relative steering shaft assembly speeds relative to a rotational position of the steering shaft assembly in accordance with the kinematics data, analyzing graphs of the steering shaft assembly speeds for phasing compliance, and analyzing graphs of the steering shaft assembly speeds for relative speed compliance. Finally, phasing the yokes on either end of the intermediate shaft of the steering shaft assembly in accordance with the speed of the steering shaft and the speed of the gearbox input shaft is accomplished.

Abstract: Determination values are obtained by calculating values for each partial model of a complete model base at each unit time, and by integrating absolute values of change amounts of the values and absolute value of change amount of a product of at least two values, according to the engine acceleration pattern. A set of the determination values including a specific determination value of a specific partial model having the most influence on a specific value calculated using the model base is selected, wherein the specific determination value is the largest among the determination values of all the partial models. A higher priority is assigned to a partial model with a higher determination value. The model base is determined by omitting a partial model from the complete model base in order of ascending priority until a desired processing load of calculating the specific value is obtained.

Abstract: A variable speed transmission having a plurality of tilting balls and opposing input and output discs is illustrated and described that provides an infinite number of speed combinations over its transmission ratio range. The use of a planetary gear set allows minimum speeds to be in reverse and the unique geometry of the transmission allows all of the power paths to be coaxial, thereby reducing overall size and complexity of the transmission in comparison to transmissions achieving similar transmission ratio ranges.

Abstract: A method of controlling hydraulic pressure to a torque converter is provided. The method includes: determining a slip error from a target slip value and a measured slip; integrating said slip error; determining a state space feedback control matrix for said measured slip; determining a state space feedback control matrix for said integrated slip error; and controlling pressure based on said state space feedback control matrix for said measured slip and said state space feedback control matrix for said integrated slip error.

Abstract: A method and apparatus for predicting the shape of a contact region of a finite element model deformed against a contact surface. The contact surface may be a rigid body or another finite element model. The shape of a contact region is dictated by the node/element distribution in response to a simulated load. This procedure uses curve fitting to predict the boundary of a contact region for a specified load condition based upon an analysis of contact region shapes generated by finite element analysis for each load within a range of simulated loads. In this manner, the discrete nature of the contact region boundary associated with finite element analysis results at a single load is overcome using information derived from previous load simulations. The approach improves the accuracy and resolution of simulated contact shape boundaries without a corresponding increase in processing resources.

Abstract: A method for estimating the cylinder interior pressure of an internal combustion engine from a cylinder pressure model having at least the input variables load, speed of rotation, and crank angle (Ppressure model), which forms the cylinder interior pressure (Pgas) to be determined, corrected by a pressure correction value (?Pgas). The pressure correction value (?Pgas) is determined from an observation of the alternating moments at the crankshaft. The modeled value of the cylinder interior pressure from the pressure model is obtained as a pre-control value, and corrected with a correction value formed from the measured value of the non-uniformity of rotation.

Abstract: A method of loading material into a dump body of a truck using a loading bucket whose volumetric capacity is approximately ? or more than that of the dump body is provided. The dump body having side walls that are spaced relatively wider than conventional dump bodies. The loading bucket having a gate at a lower end thereof that when free swings open and causes the material contained in the loading bucket to drop into the dump body. The method including the steps of filling the loading bucket with an amount of earthen material and centering the loading bucket over the dump body. The bucket is then lowered to a position that: (1) substantially minimizes the clearance between the floor of the dump body and the swinging gate in its freed position; (2) allows the swinging gate to clear the side walls of the dump body as it swings through an arc after it is freed, and (3) allows the material to be discharged substantially in the center of the dump body.

Abstract: A design of a tire can be facilitated. An optimization apparatus 30 inputs known design parameters of the shape, structure, and pattern of a tire, and performances thereof by an experimental data input unit 40 and learns, as a conversion system of a neural network, a correlation between design parameters of the shape, structure, and pattern of the tire, and performances thereof. Ranges which constrain performances of the tire and design parameters of the shape, structure, and pattern of the tire, which are to be optimized, are inputted in an optimization item input unit 42, and the performances of the tire are predicted in an optimization calculation unit 34 from the design parameters of the shape, structure, and pattern of the tire by using the optimization item and models of the calculation unit 32, and an objective function is optimized until the objective function which is the performances of the tire is converged.

Abstract: A method for forecasting performance for and characterizing the properties of a multilayer low permeability gas reservoir. The method includes a coupled well/reservoir predictive model that accounts for pressure drop between layers, allowing accurate, rigorous, and rapid forecasting of reservoir performance. The method provides estimates of individual layer properties such as in-situ permeability, skin factor, fracture half-length, fracture conductivity, drainage area, etc. by simultaneously history matching production data and production log data using the coupled well/reservoir predictive model.

Abstract: A system is provided for full-vehicle analytical road-loads prediction, which reduces the time and cost of modeling tires and tire-road interface, using road load simulations rather than actual measurements. The system includes a method to perform tire tests in a virtual environment, a road-load tire model for simulations in multibody environments; a tire model for FE simulations; and a comprehensive graphical user interface to support the user in all the steps of the analytical process.

Abstract: Detection of the overstepping of design loads of an aircraft tailplane may include determining current bending and twisting moments applied to the aircraft. The determined bending and twisting moments are compared with a safety envelope to determine the risk of developing permanent deformations on the tailplane. A determination is made as to whether a structural inspection of the tailplane should be performed based on the comparison result.

Abstract: Aircraft leading edge device systems and methods for sizing such systems are disclosed. In one embodiment, a spanwise lift coefficient distribution for an airfoil corresponding to at least one design condition and at least one aircraft angle of attack is identified, and a leading edge device chord length is sized to at least approximately achieve the selected spanwise lift coefficient distribution. In another embodiment, a spanwise distribution of aircraft angles of attack corresponding to local maximum lift coefficients for an airfoil operated at a design condition is identified, and a leading edge device chord length at each of a plurality of spanwise locations is sized to achieve the distribution of aircraft angles of attack corresponding to local maximum lift coefficients. In yet another embodiment, a leading edge device chord length is tapered in two, at least approximately opposite, spanwise directions.

Abstract: A system or method for controlling the delivery of fuel into the transient flow of an exhaust system to control emissions. A mathematical model representative of the exhaust system can be used to determine, based on operating conditions of the exhaust system, a rate of fuel delivery suitable for achieving a desired result. The desired result can be to increase the temperature of a diesel particulate filter to a temperature suitable for regeneration without exceeding a temperature that may damage the diesel particulate filter.

Abstract: A computer-implemented-ergonomic system for designing manufacturing workstations is provided. The system includes a data store for storing a plurality of workstation templates. Each workstation template includes parameters for a particular type of manufacturing workstation. Additionally, the system provides a data store for storing vehicle data indicative of a vehicle to be manufactured in the workstation. In another aspect of the present invention, the system includes a configuration subsystem adaptive to receive vehicle data and at least one workstation template and operative to configure the workstation template for the vehicle. Additionally, the system provides a data store for storing ergonomic design rules that govern a design of a manufacturing workstation. The system further includes an evaluation subsystem adaptive to receive the ergonomic design rules in data communication with the configuration subsystem.

Abstract: Disclosed is to provide a design method and design system for a vehicular lamp, a program to execute designing of vehicular lamp and a record medium recording the program, which are capable of improving an efficiency of designing a lamp satisfying design conditions including performance conditions required as the vehicular lamp and restriction conditions given to each lamp. A vehicular lamp design system 1 includes: a database unit 2 having standard database 21 registering standard data of a lamp and technology database 22 registering technology data including shape templates utilizable as shape data; and a lamp preparation unit 3. The standard data selection part 31 of the lamp preparation unit 3 generates design data by selecting standard data from the standard database 21 based on given design conditions. The morphing control part 32 updates the design data by use of the parameterized shape templates of the technology database 22 and the like.

Abstract: A method for designing a PAB door for an invisible airbag provided to a passenger-side seat of a vehicle includes defining levels of a noise factor depending on a process condition of laser scoring for forming a tearseam on an inner surface of an instrument panel. Control factors and levels of each control factor are defined that affect stress distribution and deformation rate of the tearseam. A combination is arranged that includes levels of the control factors according to an experimental design, inputting each noise factor to each combination and measuring a minimum impulse ‘X’ that is able to tear the tearseam, and a maximum impulse ‘Z’ that is unable to tear the tearseam in the case of a head impact. The level of each control factor is selected based on the measured minimum impulse ‘X’ and the measured maximum impulse ‘Z’.

Abstract: A system and method for computer-aided engineering analysis using direct mesh manipulation of a mesh model is provided. The system includes a computer system having a memory, a processor, a user input device and a display device. The method includes the steps of selecting a geometric model in a computer-aided design (CAD) format, converting the CAD model into a mesh model and evaluating the mesh model using a computer-aided engineering (CAE) analysis. The method also includes the steps of modifying a surface of the mesh model by varying a predetermined parameter using direct surface manipulation (DSM), updating the mesh model and using the updated mesh model in further CAE analysis.

Abstract: A method of calculating probability of collision by birds within a wind park includes modeling a wind turbine to create a wind-turbine model, modeling a challenged bird to create a challenged-bird model, modeling a wind park to create a wind-park model, the wind park comprising at least one of the wind turbine, and calculating a probability of wind-turbine collision by the challenged bird. The step of calculating includes using the wind-turbine model, the challenged-bird model, and the wind-park model. A method for calculating a probability of collision by animals other than birds with structures including, but not limited to, wind turbines, is also disclosed.

Abstract: A vertical stabilizer is configured to minimize the rate of change of cross-sectional area distribution of the vehicle or device to which the vertical stabilizer is mounted. One or more “waisted” areas can be included at the tip and/or the root of the vertical stabilizers, as well as over the distance from tip to root of the vertical stabilizer. In some situations, a strake is mounted on the vehicle or device, such as an aircraft, and the vertical stabilizer is mounted to the tip of the strake. The strake can also be area ruled with one or more “waisted” sections at the juncture of the vertical stabilizer. Applying area ruling to the vertical stabilizer helps to further reduce the drag of the vehicle or device.

Abstract: A method and an apparatus for estimating tire/wheel performance by simulation is disclosed, wherein a tire/wheel assembly model of an assembly of a wheel and a tire mounted thereon is made, and a simulation of the tire/wheel assembly model rolling under a given condition is carried out to obtain an estimated data indicating performance or a characteristic of the tire, wheel or the assembly. Preferably, the tire/wheel assembly model is made through a simulation of mounting a tire model on a wheel model, taking a friction into consideration. Also, the rolling simulation is carried out taking a friction between the tire beads and wheel rim into consideration.

Abstract: An analysis model producing/assisting apparatus produces a recognition model, approximating surfaces of configuration and ridgelines thereof by planes and lines, from a configuration model showing the configuration. Thereafter, it produces a mapping model through dividing the recognition model into cubic grids, and then produces an analysis model, through mapping grid points of the mapping model onto the configuration model. When producing the recognition model, know-how for producing the analysis model, which gives an influence upon quality of the meshes of the analysis model, is take out from a database, and that know-how for producing the analysis model is applied onto the configuration model.

Abstract: A simulator for inter-vehicle radio communication includes terrain and building data and can simulate the effects of buildings in terrain on radio propagation. The simulator also models other vehicles and the shadow effects of their presence. The system comprises a simulation engine, a network simulator, a driving simulator, a database and a user interface module adapted for communication. The simulation engine simulates the propagation of communication signals between vehicles including the effects of shadowing, and also receives data from the network simulator, the driving simulator and database to generate the propagation simulation. The simulation engine outputs the results of the propagation simulation to the user interface module which translates the information into various displays.

Abstract: This invention has as its object to efficiently and effectively plan a vehicle. To accomplish this, this invention has an exterior model building program (63) for building an exterior model having information associated with the exterior of a vehicle, a reference model building program (64) for building a reference model having information associated with reference components of the vehicle, and information associated with the sitting positions and postures of passengers, and a display program (65) for superimposing the built exterior model and reference model on the basis of a predetermined rule.

Abstract: A graphical user interface devices, methods, and systems for creating and editing a simulation model and for presenting the simulation model simulated within a scenario are provided. The device includes a first component that allows a user to enter and edit platforms and associated attributes for the simulation model. Commodities can be entered, edited via a second component, or assigned to a platform via a third component. A directory structure includes an organizational units and platform directory structures. The platform directory structures store platform information based on platform type. Platforms, commodities, or scenario aspects can be reviewed and edited using a graphical user interface. The present invention provides an output for allowing a user to view commodity usage at any desired aspect of the simulation model. The simulation model is created using a simulation reference modeling language.

Abstract: A method of making a finite element model of a tire is disclosed. The tire is provided in a tread portion with a fine groove having a dead end including at least the bottom. The tread portion is divided into elements so that the elements include first elements on one side of the fine groove and second elements on the other side of the fine groove, and the first elements and second elements have nodes in common at the dead end, but the first elements and second elements do not have nodes in common at other positions than the dead end.