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Sample records for aero-propulsion system simulation

  1. Modular Aero-Propulsion System Simulation

    NASA Technical Reports Server (NTRS)

    Parker, Khary I.; Guo, Ten-Huei

    2006-01-01

    The Modular Aero-Propulsion System Simulation (MAPSS) is a graphical simulation environment designed for the development of advanced control algorithms and rapid testing of these algorithms on a generic computational model of a turbofan engine and its control system. MAPSS is a nonlinear, non-real-time simulation comprising a Component Level Model (CLM) module and a Controller-and-Actuator Dynamics (CAD) module. The CLM module simulates the dynamics of engine components at a sampling rate of 2,500 Hz. The controller submodule of the CAD module simulates a digital controller, which has a typical update rate of 50 Hz. The sampling rate for the actuators in the CAD module is the same as that of the CLM. MAPSS provides a graphical user interface that affords easy access to engine-operation, engine-health, and control parameters; is used to enter such input model parameters as power lever angle (PLA), Mach number, and altitude; and can be used to change controller and engine parameters. Output variables are selectable by the user. Output data as well as any changes to constants and other parameters can be saved and reloaded into the GUI later.

  2. Commercial Modular Aero-Propulsion System Simulation 40k

    NASA Technical Reports Server (NTRS)

    Guo, Ten-Huei; Lavelle, Thomas; Litt, Jonathan; Csank, Jeffrey; May, Ryan

    2011-01-01

    The Commercial Modular Aero-Propulsion System Simulation 40k (CMAPSS40k) software package is a nonlinear dynamic simulation of a 40,000-pound (approximately equals 178-kN) thrust class commercial turbofan engine, written in the MATLAB/Simulink environment. The model has been tuned to capture the behavior of flight test data, and is capable of running at any point in the flight envelope [up to 40,000 ft (approximately equals 12,200 m) and Mach 0.8]. In addition to the open-loop engine, the simulation includes a controller whose architecture is representative of that found in industry. C-MAPSS40k fills the need for an easy-to-use, realistic, transient simulation of a medium-size commercial turbofan engine with a representative controller. It is a detailed component level model (CLM) written in the industry-standard graphical MATLAB/Simulink environment to allow for easy modification and portability. At the time of this reporting, no other such model exists in the public domain.

  3. A Modular Aero-Propulsion System Simulation of a Large Commercial Aircraft Engine

    NASA Technical Reports Server (NTRS)

    DeCastro, Jonathan A.; Litt, Jonathan S.; Frederick, Dean K.

    2008-01-01

    A simulation of a commercial engine has been developed in a graphical environment to meet the increasing need across the controls and health management community for a common research and development platform. This paper describes the Commercial Modular Aero Propulsion System Simulation (C-MAPSS), which is representative of a 90,000-lb thrust class two spool, high bypass ratio commercial turbofan engine. A control law resembling the state-of-the-art on board modern aircraft engines is included, consisting of a fan-speed control loop supplemented by relevant engine limit protection regulator loops. The objective of this paper is to provide a top-down overview of the complete engine simulation package.

  4. User's Guide for the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS): Version 2

    NASA Technical Reports Server (NTRS)

    Liu, Yuan; Frederick, Dean K.; DeCastro, Jonathan A.; Litt, Jonathan S.; Chan, William W.

    2012-01-01

    This report is a Users Guide for version 2 of the NASA-developed Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) software, which is a transient simulation of a large commercial turbofan engine (up to 90,000-lb thrust) with a realistic engine control system. The software supports easy access to health, control, and engine parameters through a graphical user interface (GUI). C-MAPSS v.2 has some enhancements over the original, including three actuators rather than one, the addition of actuator and sensor dynamics, and an improved controller, while retaining or improving on the convenience and user-friendliness of the original. C-MAPSS v.2 provides the user with a graphical turbofan engine simulation environment in which advanced algorithms can be implemented and tested. C-MAPSS can run user-specified transient simulations, and it can generate state-space linear models of the nonlinear engine model at an operating point. The code has a number of GUI screens that allow point-and-click operation, and have editable fields for user-specified input. The software includes an atmospheric model which allows simulation of engine operation at altitudes from sea level to 40,000 ft, Mach numbers from 0 to 0.90, and ambient temperatures from -60 to 103 F. The package also includes a power-management system that allows the engine to be operated over a wide range of thrust levels throughout the full range of flight conditions.

  5. Dynamic Systems Analysis for Turbine Based Aero Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Csank, Jeffrey T.

    2016-01-01

    The aircraft engine design process seeks to optimize the overall system-level performance, weight, and cost for a given concept. Steady-state simulations and data are used to identify trade-offs that should be balanced to optimize the system in a process known as systems analysis. These systems analysis simulations and data may not adequately capture the true performance trade-offs that exist during transient operation. Dynamic systems analysis provides the capability for assessing the dynamic tradeoffs at an earlier stage of the engine design process. The dynamic systems analysis concept, developed tools, and potential benefit are presented in this paper. To provide this capability, the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) was developed to provide the user with an estimate of the closed-loop performance (response time) and operability (high pressure compressor surge margin) for a given engine design and set of control design requirements. TTECTrA along with engine deterioration information, can be used to develop a more generic relationship between performance and operability that can impact the engine design constraints and potentially lead to a more efficient engine.

  6. Aerosciences, Aero-Propulsion and Flight Mechanics Technology Development for NASA's Next Generation Launch Technology Program

    NASA Technical Reports Server (NTRS)

    Cockrell, Charles E., Jr.

    2003-01-01

    The Next Generation Launch Technology (NGLT) program, Vehicle Systems Research and Technology (VSR&T) project is pursuing technology advancements in aerothermodynamics, aeropropulsion and flight mechanics to enable development of future reusable launch vehicle (RLV) systems. The current design trade space includes rocket-propelled, hypersonic airbreathing and hybrid systems in two-stage and single-stage configurations. Aerothermodynamics technologies include experimental and computational databases to evaluate stage separation of two-stage vehicles as well as computational and trajectory simulation tools for this problem. Additionally, advancements in high-fidelity computational tools and measurement techniques are being pursued along with the study of flow physics phenomena, such as boundary-layer transition. Aero-propulsion technology development includes scramjet flowpath development and integration, with a current emphasis on hypervelocity (Mach 10 and above) operation, as well as the study of aero-propulsive interactions and the impact on overall vehicle performance. Flight mechanics technology development is focused on advanced guidance, navigation and control (GN&C) algorithms and adaptive flight control systems for both rocket-propelled and airbreathing vehicles.

  7. Solar photovoltaic research and development program of the Air Force Aero Propulsion Laboratory. [silicon solar cell applicable to satellite power systems

    NASA Technical Reports Server (NTRS)

    Wise, J.

    1979-01-01

    Progress is reported in the following areas: laser weapon effects, solar silicon solar cell concepts, and high voltage hardened, high power system technology. Emphasis is placed on solar cells with increased energy conversion efficiency and radiation resistance characteristics for application to satellite power systems.

  8. Advanced Aero-Propulsive Mid-Lift-to-Drag Ratio Entry Vehicle for Future Exploration Missions

    NASA Technical Reports Server (NTRS)

    Campbell, C. H.; Stosaric, R. R; Cerimele, C. J.; Wong, K. A.; Valle, G. D.; Garcia, J. A.; Melton, J. E.; Munk, M. M.; Blades, E.; Kuruvila, G.; Picetti, D. J.; Hassan, B.; Kniskern, M. W.

    2012-01-01

    vehicle stage return, thus making ideas reality. These paradigm shifts include the technology maturation of advanced flexible thermal protection materials onto mid lift-to-drag ratio entry vehicles, the development of integrated supersonic aero-propulsive maneuvering, and the implementation of advanced asymmetric launch shrouds. These paradigms have significant overlap with launch vehicle stage return already being developed by the Air Force and several commercial space efforts. Completing the realization of these combined paradigms holds the key to a high-performing entry vehicle system capability that fully leverages multiple technology benefits to accomplish NASA's Exploration missions to atmospheric planetary destinations.

  9. Micro-optical Distributed Sensors for Aero Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Arnold, S.; Otugen, V.; Seasholtz, Richard G. (Technical Monitor)

    2003-01-01

    The objective of this research is to develop micro-opto-mechanical system (MOMS)-based sensors for time- and space-resolved measurements of flow properties in aerodynamics applications. The measurement technique we propose uses optical resonances in dielectric micro-spheres that can be excited by radiation tunneling from optical fibers. It exploits the tunneling-induced and morphology-dependent shifts in the resonant frequencies. The shift in the resonant frequency is dependent on the size, shape, and index of refraction of the micro-sphere. A physical change in the environment surrounding a micro-bead can change one or more of these properties of the sphere thereby causing a shift in frequency of resonance. The change of the resonance frequency can be detected with high resolution by scanning a frequency-tunable laser that is coupled into the fiber and observing the transmission spectrum at the output of the fiber. It is expected that, in the future, the measurement concept will lead to a system of distributed micro-sensors providing spatial data resolved in time and space. The present project focuses on the development and demonstration of temperature sensors using the morphology-dependent optical resonances although in the latter part of the work, we will also develop a pressure sensor. During the period covered in this report, the optical and electronic equipment necessary for the experimental work was assembled and the experimental setup was designed for the single sensor temperature measurements. Software was developed for real-time tracking of the optical resonance shifts. Some preliminary experiments were also carried out to detect temperature using a single bead in a water bath.

  10. Advances in SiC/SiC Composites for Aero-Propulsion

    NASA Technical Reports Server (NTRS)

    DiCarlo, James A.

    2013-01-01

    In the last decade, considerable progress has been made in the development and application of ceramic matrix composites consisting of silicon carbide (SiC) based matrices reinforced by small-diameter continuous-length SiC-based fibers. For example, these SiC/SiC composites are now in the early stages of implementation into hot-section components of civil aero-propulsion gas turbine engines, where in comparison to current metallic components they offer multiple advantages due to their lighter weight and higher temperature structural capability. For current production-ready SiC/SiC, this temperature capability for long time structural applications is 1250 degC, which is better than 1100 degC for the best metallic superalloys. Foreseeing that even higher structural reliability and temperature capability would continue to increase the advantages of SiC/SiC composites, progress in recent years has also been made at NASA toward improving the properties of SiC/SiC composites by optimizing the various constituent materials and geometries within composite microstructures. The primary objective of this chapter is to detail this latter progress, both fundamentally and practically, with particular emphasis on recent advancements in the materials and processes for the fiber, fiber coating, fiber architecture, and matrix, and in the design methods for incorporating these constituents into SiC/SiC microstructures with improved thermo-structural performance.

  11. Aero-Propulsion Technology (APT) Task V Low Noise ADP Engine Definition Study

    NASA Technical Reports Server (NTRS)

    Holcombe, V.

    2003-01-01

    A study was conducted to identify and evaluate noise reduction technologies for advanced ducted prop propulsion systems that would allow increased capacity operation and result in an economically competitive commercial transport. The study investigated the aero/acoustic/structural advancements in fan and nacelle technology required to match or exceed the fuel burned and economic benefits of a constrained diameter large Advanced Ducted Propeller (ADP) compared to an unconstrained ADP propulsion system with a noise goal of 5 to 10 EPNDB reduction relative to FAR 36 Stage 3 at each of the three measuring stations namely, takeoff (cutback), approach and sideline. A second generation ADP was selected to operate within the maximum nacelle diameter constrain of 160 deg to allow installation under the wing. The impact of fan and nacelle technologies of the second generation ADP on fuel burn and direct operating costs for a typical 3000 nm mission was evaluated through use of a large, twin engine commercial airplane simulation model. The major emphasis of this study focused on fan blade aero/acoustic and structural technology evaluations and advanced nacelle designs. Results of this study have identified the testing required to verify the interactive performance of these components, along with noise characteristics, by wind tunnel testing utilizing and advanced interaction rig.

  12. Advanced Aero-Propulsive Mid-Lift-to-Drag Ratio Entry Vehicle for Future Exploration Missions

    NASA Astrophysics Data System (ADS)

    Campbell, C. H.; Sostaric, R. R.; Cerimele, C. J.; Wong, K. A.; Valle, G. D.; Garcia, J. A.; Melton, J. E.; Munk, M. M.; Blades, E.; Kuruvila, G.; Picetti, D. J.; Hassan, B.; Kniskern, M. W.

    2012-06-01

    Advanced mid-L/D entry vehicles can provide performance advantages significant to mid-term robotic and human missions. Preliminary simulations with new paradigms show transonic Mach vehicle staging possible for retro-propulsion, descent and landing.

  13. Comparison of Aero/Propulsion Transition Characteristics for a Joint Strike Fighter Configuration

    NASA Technical Reports Server (NTRS)

    Naumowicz, Tim; Margason, Richard; Wardwell, Doug; Hange, Craig; Arledge, Tom; Olson, Lawerence E. (Technical Monitor)

    1996-01-01

    NASA Ames conducted a series tests of a large-scale powered model of Lockheed Martin Skunk Works' JSF STOVL configuration at the 80- by 120-Foot Wind Tunnel. The model uses a modified version of an F-16 fighter engine (a Pratt & Whitney F100-229 engine). To provide vertical flight capability, the Lockheed aircraft incorporates a forward fuselage mounted vertical lift fan in addition to an aft mounted vectoring nozzle all driven by a single engine. The lift fan is driven off the engine by means of a shaft and gear system. The data presented is for STOVL configuration 140, a wing-body-canard planform. The main goal of this testing was to obtain propulsion induced data for evaluating differences between small- and large-scale model testing during the transition flight regime between jet- and wing-borne flight. The data presented is from aerodynamic testing of the model in both the unpowered (engine-off) and powered (engine running) configurations. This data, when combined with the propulsion system thrust calibration data from the NASA Ames' Outdoor Aerodynamic Research Facility (OARF), is used to determine the propulsion induced effects during transition.

  14. Benchmarking Model Variants in Development of a Hardware-in-the-Loop Simulation System

    NASA Technical Reports Server (NTRS)

    Aretskin-Hariton, Eliot D.; Zinnecker, Alicia M.; Kratz, Jonathan L.; Culley, Dennis E.; Thomas, George L.

    2016-01-01

    Distributed engine control architecture presents a significant increase in complexity over traditional implementations when viewed from the perspective of system simulation and hardware design and test. Even if the overall function of the control scheme remains the same, the hardware implementation can have a significant effect on the overall system performance due to differences in the creation and flow of data between control elements. A Hardware-in-the-Loop (HIL) simulation system is under development at NASA Glenn Research Center that enables the exploration of these hardware dependent issues. The system is based on, but not limited to, the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k). This paper describes the step-by-step conversion from the self-contained baseline model to the hardware in the loop model, and the validation of each step. As the control model hardware fidelity was improved during HIL system development, benchmarking simulations were performed to verify that engine system performance characteristics remained the same. The results demonstrate the goal of the effort; the new HIL configurations have similar functionality and performance compared to the baseline C-MAPSS40k system.

  15. Development of a Twin-spool Turbofan Engine Simulation Using the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS)

    NASA Technical Reports Server (NTRS)

    Zinnecker, Alicia M.; Chapman, Jeffryes W.; Lavelle, Thomas M.; Litt, Johathan S.

    2014-01-01

    The Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS) is a tool that has been developed to allow a user to build custom models of systems governed by thermodynamic principles using a template to model each basic process. Validation of this tool in an engine model application was performed through reconstruction of the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) (v2) using the building blocks from the T-MATS (v1) library. In order to match the two engine models, it was necessary to address differences in several assumptions made in the two modeling approaches. After these modifications were made, validation of the engine model continued by integrating both a steady-state and dynamic iterative solver with the engine plant and comparing results from steady-state and transient simulation of the T-MATS and C-MAPSS models. The results show that the T-MATS engine model was accurate within 3 of the C-MAPSS model, with inaccuracy attributed to the increased dimension of the iterative solver solution space required by the engine model constructed using the T-MATS library. This demonstrates that, given an understanding of the modeling assumptions made in T-MATS and a baseline model, the T-MATS tool provides a viable option for constructing a computational model of a twin-spool turbofan engine that may be used in simulation studies.

  16. Development of a Twin-Spool Turbofan Engine Simulation Using the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS)

    NASA Technical Reports Server (NTRS)

    Zinnecker, Alicia M.; Chapman, Jeffryes W.; Lavelle, Thomas M.; Litt, Jonathan S.

    2014-01-01

    The Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) is a tool that has been developed to allow a user to build custom models of systems governed by thermodynamic principles using a template to model each basic process. Validation of this tool in an engine model application was performed through reconstruction of the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) (v2) using the building blocks from the T-MATS (v1) library. In order to match the two engine models, it was necessary to address differences in several assumptions made in the two modeling approaches. After these modifications were made, validation of the engine model continued by integrating both a steady-state and dynamic iterative solver with the engine plant and comparing results from steady-state and transient simulation of the T-MATS and C-MAPSS models. The results show that the T-MATS engine model was accurate within 3% of the C-MAPSS model, with inaccuracy attributed to the increased dimension of the iterative solver solution space required by the engine model constructed using the T-MATS library. This demonstrates that, given an understanding of the modeling assumptions made in T-MATS and a baseline model, the T-MATS tool provides a viable option for constructing a computational model of a twin-spool turbofan engine that may be used in simulation studies.

  17. Engine Icing Modeling and Simulation (Part 2): Performance Simulation of Engine Rollback Phenomena

    NASA Technical Reports Server (NTRS)

    May, Ryan D.; Guo, Ten-Huei; Veres, Joseph P.; Jorgenson, Philip C. E.

    2011-01-01

    Ice buildup in the compressor section of a commercial aircraft gas turbine engine can cause a number of engine failures. One of these failure modes is known as engine rollback: an uncommanded decrease in thrust accompanied by a decrease in fan speed and an increase in turbine temperature. This paper describes the development of a model which simulates the system level impact of engine icing using the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k). When an ice blockage is added to C-MAPSS40k, the control system responds in a manner similar to that of an actual engine, and, in cases with severe blockage, an engine rollback is observed. Using this capability to simulate engine rollback, a proof-of-concept detection scheme is developed and tested using only typical engine sensors. This paper concludes that the engine control system s limit protection is the proximate cause of iced engine rollback and that the controller can detect the buildup of ice particles in the compressor section. This work serves as a feasibility study for continued research into the detection and mitigation of engine rollback using the propulsion control system.

  18. Future Air Force aircraft propulsion control systems: The extended summary paper

    NASA Technical Reports Server (NTRS)

    Skira, C. A.

    1980-01-01

    Hydromechanical control technology simply cannot compete against the performance benefits offered by electronics. Future military aircraft propulsion control systems will be full authority, digital electronic, microprocessor base systems. Anticipating the day when microprocessor technology will permit the integration and management of aircraft flight control, fire control and propulsion control systems, the Air Force Aero Propulsion Laboratory is developing control logic algorithms for a real time, adaptive control and diagnostic information system.

  19. Extending the Capabilities of Closed-loop Distributed Engine Control Simulations Using LAN Communication

    NASA Technical Reports Server (NTRS)

    Aretskin-Hariton, Eliot D.; Zinnecker, Alicia Mae; Culley, Dennis E.

    2014-01-01

    Distributed Engine Control (DEC) is an enabling technology that has the potential to advance the state-of-the-art in gas turbine engine control. To analyze the capabilities that DEC offers, a Hardware-In-the-Loop (HIL) test bed is being developed at NASA Glenn Research Center. This test bed will support a systems-level analysis of control capabilities in closed-loop engine simulations. The structure of the HIL emulates a virtual test cell by implementing the operator functions, control system, and engine on three separate computers. This implementation increases the flexibility and extensibility of the HIL. Here, a method is discussed for implementing these interfaces by connecting the three platforms over a dedicated Local Area Network (LAN). This approach is verified using the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k), which is typically implemented on one computer. There are marginal differences between the results from simulation of the typical and the three-computer implementation. Additional analysis of the LAN network, including characterization of network load, packet drop, and latency, is presented. The three-computer setup supports the incorporation of complex control models and proprietary engine models into the HIL framework.

  20. Model-Based Control of a Nonlinear Aircraft Engine Simulation using an Optimal Tuner Kalman Filter Approach

    NASA Technical Reports Server (NTRS)

    Connolly, Joseph W.; Csank, Jeffrey Thomas; Chicatelli, Amy; Kilver, Jacob

    2013-01-01

    This paper covers the development of a model-based engine control (MBEC) methodology featuring a self tuning on-board model applied to an aircraft turbofan engine simulation. Here, the Commercial Modular Aero-Propulsion System Simulation 40,000 (CMAPSS40k) serves as the MBEC application engine. CMAPSS40k is capable of modeling realistic engine performance, allowing for a verification of the MBEC over a wide range of operating points. The on-board model is a piece-wise linear model derived from CMAPSS40k and updated using an optimal tuner Kalman Filter (OTKF) estimation routine, which enables the on-board model to self-tune to account for engine performance variations. The focus here is on developing a methodology for MBEC with direct control of estimated parameters of interest such as thrust and stall margins. Investigations using the MBEC to provide a stall margin limit for the controller protection logic are presented that could provide benefits over a simple acceleration schedule that is currently used in traditional engine control architectures.

  1. Application of the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) for Dynamic Systems Analysis

    NASA Technical Reports Server (NTRS)

    Csank, Jeffrey Thomas; Zinnecker, Alicia Mae

    2014-01-01

    Systems analysis involves steady-state simulations of combined components to evaluate the steady-state performance, weight, and cost of a system; dynamic considerations are not included until later in the design process. The Dynamic Systems Analysis task, under NASAs Fixed Wing project, is developing the capability for assessing dynamic issues at earlier stages during systems analysis. To provide this capability the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) has been developed to design a single flight condition controller (defined as altitude and Mach number) and, ultimately, provide an estimate of the closed-loop performance of the engine model. This tool has been integrated with the Commercial Modular Aero-Propulsion System Simulation 40,000 (CMAPSS 40k) engine model to demonstrate the additional information TTECTrA makes available for dynamic systems analysis. This dynamic data can be used to evaluate the trade-off between performance and safety, which could not be done with steady-state systems analysis data. TTECTrA has been designed to integrate with any turbine engine model that is compatible with the MATLAB Simulink (The MathWorks, Inc.) environment.

  2. Application of the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) for Dynamic Systems Analysis

    NASA Technical Reports Server (NTRS)

    Csank, Jeffrey; Zinnecker, Alicia

    2014-01-01

    Systems analysis involves steady-state simulations of combined components to evaluate the steady-state performance, weight, and cost of a system; dynamic considerations are not included until later in the design process. The Dynamic Systems Analysis task, under NASAs Fixed Wing project, is developing the capability for assessing dynamic issues at earlier stages during systems analysis. To provide this capability the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) has been developed to design a single flight condition controller (defined as altitude and Mach number) and, ultimately, provide an estimate of the closed-loop performance of the engine model. This tool has been integrated with the Commercial Modular Aero-Propulsion System Simulation 40,000(CMAPSS40k) engine model to demonstrate the additional information TTECTrA makes available for dynamic systems analysis. This dynamic data can be used to evaluate the trade-off between performance and safety, which could not be done with steady-state systems analysis data. TTECTrA has been designed to integrate with any turbine engine model that is compatible with the MATLABSimulink (The MathWorks, Inc.) environment.

  3. Distribution system simulator

    NASA Technical Reports Server (NTRS)

    Bahrami, K. A.; Kirkham, H.; Rahman, S.

    1986-01-01

    In a series of tests performed under the Department of Energy auspices, power line carrier propagation was observed to be anomalous under certain circumstances. To investigate the cause, a distribution system simulator was constructed. The simulator was a physical simulator that accurately represented the distribution system from below power frequency to above 50 kHz. Effects such as phase-to-phase coupling and skin effect were modeled. Construction details of the simulator, and experimental results from its use are presented.

  4. Instrumented Architectural Simulation System

    NASA Technical Reports Server (NTRS)

    Delagi, B. A.; Saraiya, N.; Nishimura, S.; Byrd, G.

    1987-01-01

    Simulation of systems at an architectural level can offer an effective way to study critical design choices if (1) the performance of the simulator is adequate to examine designs executing significant code bodies, not just toy problems or small application fragements, (2) the details of the simulation include the critical details of the design, (3) the view of the design presented by the simulator instrumentation leads to useful insights on the problems with the design, and (4) there is enough flexibility in the simulation system so that the asking of unplanned questions is not suppressed by the weight of the mechanics involved in making changes either in the design or its measurement. A simulation system with these goals is described together with the approach to its implementation. Its application to the study of a particular class of multiprocessor hardware system architectures is illustrated.

  5. Observing System Simulation Experiments

    NASA Technical Reports Server (NTRS)

    Prive, Nikki

    2015-01-01

    This presentation gives an overview of Observing System Simulation Experiments (OSSEs). The components of an OSSE are described, along with discussion of the process for validating, calibrating, and performing experiments. a.

  6. A Modular Framework for Modeling Hardware Elements in Distributed Engine Control Systems

    NASA Technical Reports Server (NTRS)

    Zinnecker, Alicia M.; Culley, Dennis E.; Aretskin-Hariton, Eliot D.

    2015-01-01

    Progress toward the implementation of distributed engine control in an aerospace application may be accelerated through the development of a hardware-in-the-loop (HIL) system for testing new control architectures and hardware outside of a physical test cell environment. One component required in an HIL simulation system is a high-fidelity model of the control platform: sensors, actuators, and the control law. The control system developed for the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k) provides a verifiable baseline for development of a model for simulating a distributed control architecture. This distributed controller model will contain enhanced hardware models, capturing the dynamics of the transducer and the effects of data processing, and a model of the controller network. A multilevel framework is presented that establishes three sets of interfaces in the control platform: communication with the engine (through sensors and actuators), communication between hardware and controller (over a network), and the physical connections within individual pieces of hardware. This introduces modularity at each level of the model, encouraging collaboration in the development and testing of various control schemes or hardware designs. At the hardware level, this modularity is leveraged through the creation of a SimulinkR library containing blocks for constructing smart transducer models complying with the IEEE 1451 specification. These hardware models were incorporated in a distributed version of the baseline C-MAPSS40k controller and simulations were run to compare the performance of the two models. The overall tracking ability differed only due to quantization effects in the feedback measurements in the distributed controller. Additionally, it was also found that the added complexity of the smart transducer models did not prevent real-time operation of the distributed controller model, a requirement of an HIL system.

  7. A Modular Framework for Modeling Hardware Elements in Distributed Engine Control Systems

    NASA Technical Reports Server (NTRS)

    Zinnecker, Alicia M.; Culley, Dennis E.; Aretskin-Hariton, Eliot D.

    2014-01-01

    Progress toward the implementation of distributed engine control in an aerospace application may be accelerated through the development of a hardware-in-the-loop (HIL) system for testing new control architectures and hardware outside of a physical test cell environment. One component required in an HIL simulation system is a high-fidelity model of the control platform: sensors, actuators, and the control law. The control system developed for the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k) provides a verifiable baseline for development of a model for simulating a distributed control architecture. This distributed controller model will contain enhanced hardware models, capturing the dynamics of the transducer and the effects of data processing, and a model of the controller network. A multilevel framework is presented that establishes three sets of interfaces in the control platform: communication with the engine (through sensors and actuators), communication between hardware and controller (over a network), and the physical connections within individual pieces of hardware. This introduces modularity at each level of the model, encouraging collaboration in the development and testing of various control schemes or hardware designs. At the hardware level, this modularity is leveraged through the creation of a Simulink(R) library containing blocks for constructing smart transducer models complying with the IEEE 1451 specification. These hardware models were incorporated in a distributed version of the baseline C-MAPSS40k controller and simulations were run to compare the performance of the two models. The overall tracking ability differed only due to quantization effects in the feedback measurements in the distributed controller. Additionally, it was also found that the added complexity of the smart transducer models did not prevent real-time operation of the distributed controller model, a requirement of an HIL system.

  8. A Modular Framework for Modeling Hardware Elements in Distributed Engine Control Systems

    NASA Technical Reports Server (NTRS)

    Zinnecker, Alicia Mae; Culley, Dennis E.; Aretskin-Hariton, Eliot D.

    2014-01-01

    Progress toward the implementation of distributed engine control in an aerospace application may be accelerated through the development of a hardware-in-the-loop (HIL) system for testing new control architectures and hardware outside of a physical test cell environment. One component required in an HIL simulation system is a high-fidelity model of the control platform: sensors, actuators, and the control law. The control system developed for the Commercial Modular Aero-Propulsion System Simulation 40k (40,000 pound force thrust) (C-MAPSS40k) provides a verifiable baseline for development of a model for simulating a distributed control architecture. This distributed controller model will contain enhanced hardware models, capturing the dynamics of the transducer and the effects of data processing, and a model of the controller network. A multilevel framework is presented that establishes three sets of interfaces in the control platform: communication with the engine (through sensors and actuators), communication between hardware and controller (over a network), and the physical connections within individual pieces of hardware. This introduces modularity at each level of the model, encouraging collaboration in the development and testing of various control schemes or hardware designs. At the hardware level, this modularity is leveraged through the creation of a Simulink (R) library containing blocks for constructing smart transducer models complying with the IEEE 1451 specification. These hardware models were incorporated in a distributed version of the baseline C-MAPSS40k controller and simulations were run to compare the performance of the two models. The overall tracking ability differed only due to quantization effects in the feedback measurements in the distributed controller. Additionally, it was also found that the added complexity of the smart transducer models did not prevent real-time operation of the distributed controller model, a requirement of an HIL

  9. Future NASA Power Technologies for Space and Aero Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Soeder, James F.

    2015-01-01

    To achieve the ambitious goals that NASA has outlined for the next decades considerable development of power technology will be necessary. This presentation outlines the development objectives for both space and aero applications. It further looks at the various power technologies that support these objectives and examines drivers that will be a driving force for future development. Finally, the presentation examines what type of non-traditional learning areas should be emphasized in student curriculum so that the engineering needs of the third decade of the 21st Century are met.

  10. Numerical Propulsion System Simulation

    NASA Technical Reports Server (NTRS)

    Naiman, Cynthia

    2006-01-01

    The NASA Glenn Research Center, in partnership with the aerospace industry, other government agencies, and academia, is leading the effort to develop an advanced multidisciplinary analysis environment for aerospace propulsion systems called the Numerical Propulsion System Simulation (NPSS). NPSS is a framework for performing analysis of complex systems. The initial development of NPSS focused on the analysis and design of airbreathing aircraft engines, but the resulting NPSS framework may be applied to any system, for example: aerospace, rockets, hypersonics, power and propulsion, fuel cells, ground based power, and even human system modeling. NPSS provides increased flexibility for the user, which reduces the total development time and cost. It is currently being extended to support the NASA Aeronautics Research Mission Directorate Fundamental Aeronautics Program and the Advanced Virtual Engine Test Cell (AVETeC). NPSS focuses on the integration of multiple disciplines such as aerodynamics, structure, and heat transfer with numerical zooming on component codes. Zooming is the coupling of analyses at various levels of detail. NPSS development includes capabilities to facilitate collaborative engineering. The NPSS will provide improved tools to develop custom components and to use capability for zooming to higher fidelity codes, coupling to multidiscipline codes, transmitting secure data, and distributing simulations across different platforms. These powerful capabilities extend NPSS from a zero-dimensional simulation tool to a multi-fidelity, multidiscipline system-level simulation tool for the full development life cycle.

  11. Software simulator for multiple computer simulation system

    NASA Technical Reports Server (NTRS)

    Ogrady, E. P.

    1983-01-01

    A description is given of the structure and use of a computer program that simulates the operation of a parallel processor simulation system. The program is part of an investigation to determine algorithms that are suitable for simulating continous systems on a parallel processor configuration. The simulator is designed to accurately simulate the problem-solving phase of a simulation study. Care has been taken to ensure the integrity and correctness of data exchanges and to correctly sequence periods of computation and periods of data exchange. It is pointed out that the functions performed during a problem-setup phase or a reset phase are not simulated. In particular, there is no attempt to simulate the downloading process that loads object code into the local, transfer, and mapping memories of processing elements or the memories of the run control processor and the system control processor. The main program of the simulator carries out some problem-setup functions of the system control processor in that it requests the user to enter values for simulation system parameters and problem parameters. The method by which these values are transferred to the other processors, however, is not simulated.

  12. Data Systems Dynamic Simulator

    NASA Technical Reports Server (NTRS)

    Rouff, Christopher; Clark, Melana; Davenport, Bill; Message, Philip

    1993-01-01

    The Data System Dynamic Simulator (DSDS) is a discrete event simulation tool. It was developed for NASA for the specific purpose of evaluating candidate architectures for data systems of the Space Station era. DSDS provides three methods for meeting this requirement. First, the user has access to a library of standard pre-programmed elements. These elements represent tailorable components of NASA data systems and can be connected in any logical manner. Secondly, DSDS supports the development of additional elements. This allows the more sophisticated DSDS user the option of extending the standard element set. Thirdly, DSDS supports the use of data streams simulation. Data streams is the name given to a technique that ignores packet boundaries, but is sensitive to rate changes. Because rate changes are rare compared to packet arrivals in a typical NASA data system, data stream simulations require a fraction of the CPU run time. Additionally, the data stream technique is considerably more accurate than another commonly-used optimization technique.

  13. Transportation Anslysis Simulation System

    SciTech Connect

    2004-08-23

    TRANSIMS version 3.1 is an integrated set of analytical and simulation models and supporting databases. The system is designed to create a virtual metropolitan region with representation of each of the region’s individuals, their activities and the transportation infrastructure they use. TRANSIMS puts into practice a new, disaggregate approach to travel demand modeling using agent-based micro-simulation technology. TRANSIMS methodology creates a virtual metropolitan region with representation of the transportation infrastructure and the population, at the level of households and individual travelers. Trips a planned to satisfy the population’s activity pattems at the individual traveler level. TRANSIMS then simulates the movement of travelers and vehicles across the transportation network using multiple modes, including car, transit, bike and walk, on a second-by-second basis. Metropolitan planners must plan growth of their cities according to the stringent transportation system planning requirements of the Interniodal Surface Transportation Efficiency Act of 1991, the Clean Air Act Amendments of 1990 and other similar laws and regulations. These require each state and its metropotitan regions to work together to develop short and long term transportation improvement plans. The plans must (1) estimate the future transportation needs for travelers and goods movements, (2) evaluate ways to manage and reduce congestion, (3) examine the effectiveness of building new roads and transit systems, and (4) limit the environmental impact of the various strategies. The needed consistent and accurate transportation improvement plans require an analytical capability that properly accounts for travel demand, human behavior, traffic and transit operations, major investments, and environmental effects. Other existing planning tools use aggregated information and representative behavior to predict average response and average use of transportation facilities. They do not account

  14. Transportation Anslysis Simulation System

    2004-08-23

    TRANSIMS version 3.1 is an integrated set of analytical and simulation models and supporting databases. The system is designed to create a virtual metropolitan region with representation of each of the region’s individuals, their activities and the transportation infrastructure they use. TRANSIMS puts into practice a new, disaggregate approach to travel demand modeling using agent-based micro-simulation technology. TRANSIMS methodology creates a virtual metropolitan region with representation of the transportation infrastructure and the population, at themore » level of households and individual travelers. Trips a planned to satisfy the population’s activity pattems at the individual traveler level. TRANSIMS then simulates the movement of travelers and vehicles across the transportation network using multiple modes, including car, transit, bike and walk, on a second-by-second basis. Metropolitan planners must plan growth of their cities according to the stringent transportation system planning requirements of the Interniodal Surface Transportation Efficiency Act of 1991, the Clean Air Act Amendments of 1990 and other similar laws and regulations. These require each state and its metropotitan regions to work together to develop short and long term transportation improvement plans. The plans must (1) estimate the future transportation needs for travelers and goods movements, (2) evaluate ways to manage and reduce congestion, (3) examine the effectiveness of building new roads and transit systems, and (4) limit the environmental impact of the various strategies. The needed consistent and accurate transportation improvement plans require an analytical capability that properly accounts for travel demand, human behavior, traffic and transit operations, major investments, and environmental effects. Other existing planning tools use aggregated information and representative behavior to predict average response and average use of transportation facilities. They do not

  15. Simulating neural systems with Xyce.

    SciTech Connect

    Schiek, Richard Louis; Thornquist, Heidi K.; Mei, Ting; Warrender, Christina E.; Aimone, James Bradley; Teeter, Corinne; Duda, Alex M.

    2012-12-01

    Sandias parallel circuit simulator, Xyce, can address large scale neuron simulations in a new way extending the range within which one can perform high-fidelity, multi-compartment neuron simulations. This report documents the implementation of neuron devices in Xyce, their use in simulation and analysis of neuron systems.

  16. Turbofan Engine Simulated in a Graphical Simulation Environment

    NASA Technical Reports Server (NTRS)

    Parker, Khary I.; Guo, Ten-Huei

    2004-01-01

    Recently, there has been an increase in the development of intelligent engine technology with advanced active component control. The computer engine models used in these control studies are component-level models (CLM), models that link individual component models of state space and nonlinear algebraic equations, written in a computer language such as Fortran. The difficulty faced in performing control studies on Fortran-based models is that Fortran is not supported with control design and analysis tools, so there is no means for implementing real-time control. It is desirable to have a simulation environment that is straightforward, has modular graphical components, and allows easy access to health, control, and engine parameters through a graphical user interface. Such a tool should also provide the ability to convert a control design into real-time code, helping to make it an extremely powerful tool in control and diagnostic system development. Simulation time management is shown: Mach number versus time, power level angle versus time, altitude versus time, ambient temperature change versus time, afterburner fuel flow versus time, controller and actuator dynamics, collect initial conditions, CAD output, and component-level model: CLM sensor, CAD input, and model output. The Controls and Dynamics Technologies Branch at the NASA Glenn Research Center has developed and demonstrated a flexible, generic turbofan engine simulation platform that can meet these objectives, known as the Modular Aero-Propulsion System Simulation (MAPSS). MAPSS is a Simulink-based implementation of a Fortran-based, modern high pressure ratio, dual-spool, low-bypass, military-type variable-cycle engine with a digital controller. Simulink (The Mathworks, Natick, MA) is a computer-aided control design and simulation package allows the graphical representation of dynamic systems in a block diagram form. MAPSS is a nonlinear, non-real-time system composed of controller and actuator dynamics

  17. Simulating The SSF Information System

    NASA Technical Reports Server (NTRS)

    Deshpande, Govind K.; Kleine, Henry; Younger, Joseph C.; Sanders, Felicia A.; Smith, Jeffrey L.; Aster, Robert W.; Olivieri, Jerry M.; Paul, Lori L.

    1993-01-01

    Freedom Operations Simulation Test (FROST) computer program simulates operation of SSF information system, tracking every packet of data from generation to destination, for both uplinks and downlinks. Collects various statistics concerning operation of system and provides reports of statistics at intervals specified by user. FROST also incorporates graphical-display capability to enhance interpretation of these statistics. Written in SIMSCRIPT 11.5.

  18. Healthcare system simulation using Witness

    NASA Astrophysics Data System (ADS)

    Khakdaman, Masoud; Zeinahvazi, Milad; Zohoori, Bahareh; Nasiri, Fardokht; Yew Wong, Kuan

    2013-02-01

    Simulation techniques have a proven track record in manufacturing industry as well as other areas such as healthcare system improvement. In this study, simulation model of a health center in Malaysia is developed through the application of WITNESS simulation software which has shown its flexibility and capability in manufacturing industry. Modelling procedure is started through process mapping and data collection and continued with model development, verification, validation and experimentation. At the end, final results and possible future improvements are demonstrated.

  19. A multiprocessor operating system simulator

    SciTech Connect

    Johnston, G.M.; Campbell, R.H. . Dept. of Computer Science)

    1988-01-01

    This paper describes a multiprocessor operating system simulator that was developed by the authors in the Fall of 1987. The simulator was built in response to the need to provide students with an environment in which to build and test operating system concepts as part of the coursework of a third-year undergraduate operating systems course. Written in C++, the simulator uses the co-routine style task package that is distributed with the AT and T C++ Translator to provide a hierarchy of classes that represents a broad range of operating system software and hardware components. The class hierarchy closely follows that of the Choices family of operating systems for loosely and tightly coupled multiprocessors. During an operating system course, these classes are refined and specialized by students in homework assignments to facilitate experimentation with different aspects of operating system design and policy decisions. The current implementation runs on the IBM RT PC under 4.3bsd UNIX.

  20. A Multiprocessor Operating System Simulator

    NASA Technical Reports Server (NTRS)

    Johnston, Gary M.; Campbell, Roy H.

    1988-01-01

    This paper describes a multiprocessor operating system simulator that was developed by the authors in the Fall semester of 1987. The simulator was built in response to the need to provide students with an environment in which to build and test operating system concepts as part of the coursework of a third-year undergraduate operating systems course. Written in C++, the simulator uses the co-routine style task package that is distributed with the AT&T C++ Translator to provide a hierarchy of classes that represents a broad range of operating system software and hardware components. The class hierarchy closely follows that of the 'Choices' family of operating systems for loosely- and tightly-coupled multiprocessors. During an operating system course, these classes are refined and specialized by students in homework assignments to facilitate experimentation with different aspects of operating system design and policy decisions. The current implementation runs on the IBM RT PC under 4.3bsd UNIX.

  1. GPS system simulation methodology

    NASA Technical Reports Server (NTRS)

    Ewing, Thomas F.

    1993-01-01

    The following topics are presented: background; Global Positioning System (GPS) methodology overview; the graphical user interface (GUI); current models; application to space nuclear power/propulsion; and interfacing requirements. The discussion is presented in vugraph form.

  2. Joint modeling and simulation system

    NASA Astrophysics Data System (ADS)

    Boyer, Richard T.; McQuay, William K.

    1993-08-01

    The defense budget is shrinking. Weapon systems are getting more complex. Test requirements are increasing. The training and war gaming scenarios are getting more demanding as fielded systems and training simulators are integrated to support combined arms training. To cope with these requirements and still stay within the budget, the Department of Defense is relying on modeling and simulation. The state of the modeling and simulation (M&S) art has advanced to the point where a user can now create incredibly realistic, extremely detailed models which can augment test and evaluation, support the acquisition process, enhance training and war gaming, facilitate intelligence gathering, and support detailed engineering.

  3. Systems Engineering Simulator (SES) Simulator Planning Guide

    NASA Technical Reports Server (NTRS)

    McFarlane, Michael

    2011-01-01

    The simulation process, milestones and inputs are unknowns to first-time users of the SES. The Simulator Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their engineering personnel in simulation planning and execution. Material covered includes a roadmap of the simulation process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, facility interfaces, and inputs necessary to define scope, cost, and schedule are included as an appendix to the guide.

  4. Real time digital propulsion system simulation for manned flight simulators

    NASA Technical Reports Server (NTRS)

    Mihaloew, J. R.; Hart, C. E.

    1978-01-01

    A real time digital simulation of a STOL propulsion system was developed which generates significant dynamics and internal variables needed to evaluate system performance and aircraft interactions using manned flight simulators. The simulation ran at a real-to-execution time ratio of 8.8. The model was used in a piloted NASA flight simulator program to evaluate the simulation technique and the propulsion system digital control. The simulation is described and results shown. Limited results of the flight simulation program are also presented.

  5. Simulations of Solar AO Systems

    NASA Astrophysics Data System (ADS)

    Sridharan, R.; Bayanna, A. Raja; Venkatakrishnan, P.

    In this paper, first we compare the two kinds of algorithms that are being used in solar AO systems to sense a distorted wave-front through simulations. Then, we comment on the various issues related to solar AO systems and describe solar features that can be studied using AO as a tool. Then we briefly describe the laboratory model of AO that is being built at the Udaipur Solar Observatory (USO), India.

  6. Aided targeting system simulation evaluation

    NASA Technical Reports Server (NTRS)

    Demaio, Joe; Becker, Curtis

    1994-01-01

    Simulation research was conducted at the Crew Station Research and Development Facility on the effectiveness and ease of use of three targeting systems. A manual system required the aviator to scan a target array area with a simulated second generation forward looking infrared (FLIR) sensor, locate and categorize targets, and construct a target hand-off list. The interface between the aviator and the system was like that of an advanced scout helicopter (manual mode). Two aided systems detected and categorized targets automatically. One system used only the FLIR sensor and the second used FLIR fused with Longbow radar. The interface for both was like that of an advanced scout helicopter aided mode. Exposure time while performing the task was reduced substantially with the aided systems, with no loss of target hand-off list accuracy. The fused sensor system showed lower time to construct the target hand-off list and a slightly lower false alarm rate than the other systems. A number of issues regarding system sensitivity and criterion, and operator interface design are discussed.

  7. Numerical Propulsion System Simulation Architecture

    NASA Technical Reports Server (NTRS)

    Naiman, Cynthia G.

    2004-01-01

    The Numerical Propulsion System Simulation (NPSS) is a framework for performing analysis of complex systems. Because the NPSS was developed using the object-oriented paradigm, the resulting architecture is an extensible and flexible framework that is currently being used by a diverse set of participants in government, academia, and the aerospace industry. NPSS is being used by over 15 different institutions to support rockets, hypersonics, power and propulsion, fuel cells, ground based power, and aerospace. Full system-level simulations as well as subsystems may be modeled using NPSS. The NPSS architecture enables the coupling of analyses at various levels of detail, which is called numerical zooming. The middleware used to enable zooming and distributed simulations is the Common Object Request Broker Architecture (CORBA). The NPSS Developer's Kit offers tools for the developer to generate CORBA-based components and wrap codes. The Developer's Kit enables distributed multi-fidelity and multi-discipline simulations, preserves proprietary and legacy codes, and facilitates addition of customized codes. The platforms supported are PC, Linux, HP, Sun, and SGI.

  8. An intelligent simulation training system

    NASA Technical Reports Server (NTRS)

    Biegel, John E.

    1990-01-01

    The Department of Industrial Engineering at the University of Central Florida, Embry-Riddle Aeronautical University and General Electric (SCSD) have been funded by the State of Florida to build an Intelligent Simulation Training System. The objective was and is to make the system generic except for the domain expertise. Researchers accomplished this objective in their prototype. The system is modularized and therefore it is easy to make any corrections, expansions or adaptations. The funding by the state of Florida has exceeded $3 million over the past three years and through the 1990 fiscal year. UCF has expended in excess of 15 work years on the project. The project effort has been broken into three major tasks. General Electric provides the simulation. Embry-Riddle Aeronautical University provides the domain expertise. The University of Central Florida has constructed the generic part of the system which is comprised of several modules that perform the tutoring, evaluation, communication, status, etc. The generic parts of the Intelligent Simulation Training Systems (ISTS) are described.

  9. Propulsion System Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Tai, Jimmy C. M.; McClure, Erin K.; Mavris, Dimitri N.; Burg, Cecile

    2002-01-01

    The Aerospace Systems Design Laboratory at the School of Aerospace Engineering in Georgia Institute of Technology has developed a core competency that enables propulsion technology managers to make technology investment decisions substantiated by propulsion and airframe technology system studies. This method assists the designer/manager in selecting appropriate technology concepts while accounting for the presence of risk and uncertainty as well as interactions between disciplines. This capability is incorporated into a single design simulation system that is described in this paper. This propulsion system design environment is created with a commercially available software called iSIGHT, which is a generic computational framework, and with analysis programs for engine cycle, engine flowpath, mission, and economic analyses. iSIGHT is used to integrate these analysis tools within a single computer platform and facilitate information transfer amongst the various codes. The resulting modeling and simulation (M&S) environment in conjunction with the response surface method provides the designer/decision-maker an analytical means to examine the entire design space from either a subsystem and/or system perspective. The results of this paper will enable managers to analytically play what-if games to gain insight in to the benefits (and/or degradation) of changing engine cycle design parameters. Furthermore, the propulsion design space will be explored probabilistically to show the feasibility and viability of the propulsion system integrated with a vehicle.

  10. Simulation of linear mechanical systems

    NASA Technical Reports Server (NTRS)

    Sirlin, S. W.

    1993-01-01

    A dynamics and controls analyst is typically presented with a structural dynamics model and must perform various input/output tests and design control laws. The required time/frequency simulations need to be done many times as models change and control designs evolve. This paper examines some simple ways that open and closed loop frequency and time domain simulations can be done using the special structure of the system equations usually available. Routines were developed to run under Pro-Matlab in a mixture of the Pro-Matlab interpreter and FORTRAN (using the .mex facility). These routines are often orders of magnitude faster than trying the typical 'brute force' approach of using built-in Pro-Matlab routines such as bode. This makes the analyst's job easier since not only does an individual run take less time, but much larger models can be attacked, often allowing the whole model reduction step to be eliminated.

  11. Simulation System Fidelity Assessment at the Vertical Motion Simulator

    NASA Technical Reports Server (NTRS)

    Beard, Steven D.; Reardon, Scott E.; Tobias, Eric L.; Aponso, Bimal L.

    2013-01-01

    Fidelity is a word that is often used but rarely understood when talking about groundbased simulation. Assessing the cueing fidelity of a ground based flight simulator requires a comparison to actual flight data either directly or indirectly. Two experiments were conducted at the Vertical Motion Simulator using the GenHel UH-60A Black Hawk helicopter math model that was directly compared to flight data. Prior to the experiment the simulator s motion and visual system frequency responses were measured, the aircraft math model was adjusted to account for the simulator motion system delays, and the motion system gains and washouts were tuned for the individual tasks. The tuned motion system fidelity was then assessed against the modified Sinacori criteria. The first experiments showed similar handling qualities ratings (HQRs) to actual flight for a bob-up and sidestep maneuvers. The second experiment showed equivalent HQRs between flight and simulation for the ADS33 slalom maneuver for the two pilot participants. The ADS33 vertical maneuver HQRs were mixed with one pilot rating the flight and simulation the same while the second pilot rated the simulation worse. In addition to recording HQRs on the second experiment, an experimental Simulation Fidelity Rating (SFR) scale developed by the University of Liverpool was tested for applicability to engineering simulators. A discussion of the SFR scale for use on the Vertical Motion Simulator is included in this paper.

  12. CASINO: A Small System Simulator

    ERIC Educational Resources Information Center

    Christensen, Borge

    1978-01-01

    This article is a tutorial on writing a simulator--the example used is a casino. The nontechnical, step by step approach is designed to enable even non-programmers to understand the design of such a simulation. (Author)

  13. DDS: The Dental Diagnostic Simulation System.

    ERIC Educational Resources Information Center

    Tira, Daniel E.

    The Dental Diagnostic Simulation (DDS) System provides an alternative to simulation systems which represent diagnostic case studies of relatively limited scope. It may be used to generate simulated case studies in all of the dental specialty areas with case materials progressing through the gamut of the diagnostic process. The generation of a…

  14. Space shuttle visual simulation system design study

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A recommendation and a specification for the visual simulation system design for the space shuttle mission simulator are presented. A recommended visual system is described which most nearly meets the visual design requirements. The cost analysis of the recommended system covering design, development, manufacturing, and installation is reported. Four alternate systems are analyzed.

  15. Simulation system of airborne FLIR searcher

    NASA Astrophysics Data System (ADS)

    Sun, Kefeng; Li, Yu; Gao, Jiaobo; Wang, Jun; Wang, Jilong; Xie, Junhu; Ding, Na; Sun, Dandan

    2014-11-01

    Airborne Forward looking infra-red (FLIR) searcher simulation system can provide multi-mode simulated test environment that almost actual field environment, and can simulate integrated performance and external interface of airborne FLIR simulation system. Furthermore, the airborne FLIR searcher simulation system can support the algorithm optimization of image processing, and support the test and evaluation of electro-optical system, and also support the line test of software and evaluate the performance of the avionics system. The detailed design structure and information cross-linking relationship of each component are given in this paper. The simulation system is composed of the simulation center, the FLIR actuator, the FLIR emulator, and the display control terminal. The simulation center can generate the simulated target and aircraft flying data in the operation state of the airborne FLIR Searcher. The FLIR actuator can provide simulation scene. It can generate the infrared target and landform based scanning scene, response to the commands from simulation center and the FLIR actuator and operation control unit. The infrared image generated by the FLIR actuator can be processed by the FLIR emulator using PowerPC hardware framework and processing software based on VxWorks system. It can detect multi-target and output the DVI video and the multi-target detection information which corresponds to the working state of the FLIR searcher. Display control terminal can display the multi-target detection information in two-dimension situation format, and realize human-computer interaction function.

  16. Improvements to information management systems simulator

    NASA Technical Reports Server (NTRS)

    Bilek, R. W.

    1972-01-01

    The performance of personnel in the augmentation and improvement of the interactive IMSIM information management simulation model is summarized. With this augmented model, NASA now has even greater capabilities for the simulation of computer system configurations, data processing loads imposed on these configurations, and executive software to control system operations. Through these simulations, NASA has an extremely cost effective capability for the design and analysis of computer-based data management systems.

  17. Relativistic positioning systems: Numerical simulations

    NASA Astrophysics Data System (ADS)

    Puchades Colmenero, Neus

    The position of users located on the Earth's surface or near it may be found with the classic positioning systems (CPS). Certain information broadcast by satellites of global navigation systems, as GPS and GALILEO, may be used for positioning. The CPS are based on the Newtonian formalism, although relativistic post-Newtonian corrections are done when they are necessary. This thesis contributes to the development of a different positioning approach, which is fully relativistic from the beginning. In the relativistic positioning systems (RPS), the space-time position of any user (ship, spacecraft, and so on) can be calculated with the help of four satellites, which broadcast their proper times by means of codified electromagnetic signals. In this thesis, we have simulated satellite 4-tuples of the GPS and GALILEO constellations. If a user receives the signals from four satellites simultaneously, the emission proper times read -after decoding- are the user "emission coordinates". In order to find the user "positioning coordinates", in an appropriate almost inertial reference system, there are two possibilities: (a) the explicit relation between positioning and emission coordinates (broadcast by the satellites) is analytically found or (b) numerical codes are designed to calculate the positioning coordinates from the emission ones. Method (a) is only viable in simple ideal cases, whereas (b) allows us to consider realistic situations. In this thesis, we have designed numerical codes with the essential aim of studying two appropriate RPS, which may be generalized. Sometimes, there are two real users placed in different positions, which receive the same proper times from the same satellites; then, we say that there is bifurcation, and additional data are needed to choose the real user position. In this thesis, bifurcation is studied in detail. We have analyzed in depth two RPS models; in both, it is considered that the satellites move in the Schwarzschild's space

  18. Simulation Of Advanced Train Control Systems

    NASA Astrophysics Data System (ADS)

    Craven, Paul; Oman, Paul

    This paper describes an Advanced Train Control System (ATCS) simulation environment created using the Network Simulator 2 (ns-2) discrete event network simulation system. The ATCS model is verified using ATCS monitoring software, laboratory results and a comparison with a mathematical model of ATCS communications. The simulation results are useful in understanding ATCS communication characteristics and identifying protocol strengths, weaknesses, vulnerabilities and mitigation techniques. By setting up a suite of ns-2 scripts, an engineer can simulate hundreds of possible scenarios in the space of a few seconds to investigate failure modes and consequences.

  19. Method for simulating discontinuous physical systems

    DOEpatents

    Baty, Roy S.; Vaughn, Mark R.

    2001-01-01

    The mathematical foundations of conventional numerical simulation of physical systems provide no consistent description of the behavior of such systems when subjected to discontinuous physical influences. As a result, the numerical simulation of such problems requires ad hoc encoding of specific experimental results in order to address the behavior of such discontinuous physical systems. In the present invention, these foundations are replaced by a new combination of generalized function theory and nonstandard analysis. The result is a class of new approaches to the numerical simulation of physical systems which allows the accurate and well-behaved simulation of discontinuous and other difficult physical systems, as well as simpler physical systems. Applications of this new class of numerical simulation techniques to process control, robotics, and apparatus design are outlined.

  20. DKIST Adaptive Optics System: Simulation Results

    NASA Astrophysics Data System (ADS)

    Marino, Jose; Schmidt, Dirk

    2016-05-01

    The 4 m class Daniel K. Inouye Solar Telescope (DKIST), currently under construction, will be equipped with an ultra high order solar adaptive optics (AO) system. The requirements and capabilities of such a solar AO system are beyond those of any other solar AO system currently in operation. We must rely on solar AO simulations to estimate and quantify its performance.We present performance estimation results of the DKIST AO system obtained with a new solar AO simulation tool. This simulation tool is a flexible and fast end-to-end solar AO simulator which produces accurate solar AO simulations while taking advantage of current multi-core computer technology. It relies on full imaging simulations of the extended field Shack-Hartmann wavefront sensor (WFS), which directly includes important secondary effects such as field dependent distortions and varying contrast of the WFS sub-aperture images.

  1. ERS-1 system simulation and calibration

    NASA Astrophysics Data System (ADS)

    Hans, P.; Braun, H. M.; Groebke, H.

    1984-08-01

    The ERS-1 Radar systems cannot totally be tested on ground, so comprehensive system simulators, able to take test results of system elements and simulate the entire system chains to derive the end-to-end measurement performances are proposed. After launch and stabilization of the spacecraft and the orbit, the inflight calibration is performed by comparison of the ERS-1 measurements with ground truth information and tuning of the target models, supported by simulations to identify whether an error is caused by the system or a model uncertainty.

  2. Integrating Existing Simulation Components into a Cohesive Simulation System

    NASA Technical Reports Server (NTRS)

    McLaughlin, Brian J.; Barrett, Larry K.

    2012-01-01

    A tradition of leveraging the re-use of components to help manage costs has evolved in the development of complex system. This tradition continues on in the Joint Polar Satellite System (JPSS) Program with the cloning of the Suomi National Polar-orbiting Partnership (NPP) satellite for the JPSS-1 mission, including the instrument complement. One benefit of re-use on a mission is the availability of existing simulation assets from the systems that were previously built. An issue arises in the continual shift of technology over a long mission, or multi-mission, lifecycle. As the missions mature, the requirements for the observatory simulations evolve. The challenge in this environment becomes re-using the existing components in that ever-changing landscape. To meet this challenge, the system must: establish an operational architecture that minimizes impacts on the implementation of individual components, consolidate the satisfaction of new high-impact requirements into system-level infrastructure, and build in a long-term view of system adaptation that spans the full lifecycle of the simulation system. The Flight Vehicle Test Suite (FVTS) within the JPSS Program is defining and executing this approach to ensure a robust simulation capability for the JPSS multi-mission environment

  3. Computer simulation of engine systems

    NASA Technical Reports Server (NTRS)

    Fishbach, L. H.

    1980-01-01

    The use of computerized simulations of the steady state and transient performance of jet engines throughout the flight regime is discussed. In addition, installation effects on thrust and specific fuel consumption is accounted for as well as engine weight, dimensions and cost. The availability throughout the government and industry of analytical methods for calculating these quantities are pointed out.

  4. Interoperability Standards for Medical Simulation Systems

    NASA Technical Reports Server (NTRS)

    Tolk, Andreas; Diallo, Saikou Y.; Padilla, Jose J.

    2012-01-01

    The Modeling and Simulation Community successfully developed and applied interoperability standards like the Distributed Interactive Simulation (DIS) protocol (IEEE 1278) and the High Level Architecture (HLA) (IEEE 1516). These standards were applied for world-wide distributed simulation events for several years. However, this paper shows that some of the assumptions and constraints underlying the philosophy of these current standards are not valid for Medical Simulation Systems. This paper describes the standards, the philosophy and the limits for medical applications and recommends necessary extensions of the standards to support medical simulation.

  5. Design of penicillin fermentation process simulation system

    NASA Astrophysics Data System (ADS)

    Qi, Xiaoyu; Yuan, Zhonghu; Qi, Xiaoxuan; Zhang, Wenqi

    2011-10-01

    Real-time monitoring for batch process attracts increasing attention. It can ensure safety and provide products with consistent quality. The design of simulation system of batch process fault diagnosis is of great significance. In this paper, penicillin fermentation, a typical non-linear, dynamic, multi-stage batch production process, is taken as the research object. A visual human-machine interactive simulation software system based on Windows operation system is developed. The simulation system can provide an effective platform for the research of batch process fault diagnosis.

  6. Description of the grout system dynamic simulation

    SciTech Connect

    Zimmerman, B.D.

    1993-07-01

    The grout system dynamic computer simulation was created to allow investigation of the ability of the grouting system to meet established milestones, for various assumed system configurations and parameters. The simulation simulates the movement of tank waste through the system versus time, from initial storage tanks, through feed tanks and the grout plant, then finally to a grout vault. The simulation properly accounts for the following (1) time required to perform various actions or processes, (2) delays involved in gaining regulatory approval, (3) random system component failures, (4) limitations on equipment capacities, (5) available parallel components, and (6) different possible strategies for vault filling. The user is allowed to set a variety of system parameters for each simulation run. Currently, the output of a run primarily consists of a plot of projected grouting campaigns completed versus time, for comparison with milestones. Other outputs involving any model component can also be quickly created or deleted as desired. In particular, sensitivity runs where the effect of varying a model parameter (flow rates, delay times, number of feed tanks available, etc.) on the ability of the system to meet milestones can be made easily. The grout system simulation was implemented using the ITHINK* simulation language for Macintosh** computers.

  7. Global Positioning System Simulator Field Operational Procedures

    NASA Technical Reports Server (NTRS)

    Kizhner, Semion; Quinn, David A.; Day, John H. (Technical Monitor)

    2002-01-01

    Global Positioning System (GPS) simulation is an important activity in the development or qualification of GPS signal receivers for space flight. Because a GPS simulator is a critical resource it is highly desirable to develop a set of field operational procedures to supplement the basic procedures provided by most simulator vendors. Validated field procedures allow better utilization of the GPS simulator in the development of new test scenarios and simulation operations. These procedures expedite simulation scenario development while resulting in scenarios that are more representative of the true design, as well as enabling construction of more complex simulations than previously possible, for example, spacecraft maneuvers. One difficulty in the development of a simulation scenario is specifying various modes of test vehicle motion and associated maneuvers requiring that a user specify some (but not all) of a few closely related simulation parameters. Currently this can only be done by trial and error. A stand-alone procedure that implements the simulator maneuver motion equations and solves for the motion profile transient times, jerk and acceleration would be of considerable value. Another procedure would permit the specification of some configuration parameters that would determine the simulated GPS signal composition. The resulting signal navigation message, for example, would force the receiver under test to use only the intended C-code component of the simulated GPS signal. A representative class of GPS simulation-related field operational procedures is described in this paper. These procedures were developed and used in support of GPS integration and testing for many successful spacecraft missions such as SAC-A, EO-1, AMSAT, VCL, SeaStar, sounding rockets, and by using the industry standard Spirent Global Simulation Systems Incorporated (GSSI) STR series simulators.

  8. Electronic notebook for physical system simulation

    SciTech Connect

    Kelsey, R. L.

    2003-01-01

    A scientist who sets up and runs experiments typically keeps notes of this process in a lab notebook. A scientist who runs computer simulations should be no different. Experiments and simulations both require a set-up process which should be documented along with the results of the experiment or simulation. The documentation is important for knowing and understanding what was attempted, what took place, and how to reproduce it in the future. Modern simulations of physical systems have become more complex due in part to larger computational resources and increased understanding of physical systems. These simulations may be performed by combining the results from multiple computer codes. The machines that these simulations are executed on are often massively parallelldistributed systems. The output result of one of these simulations can be a terabyte of data and can require months of computing. All of these things contribute to the difficulty of keeping a useful record of the process of setting up and executing a simulation for a physical system. An electronic notebook for physical system simulations has been designed to help document the set up and execution process. Much of the documenting is done automatically by the simulation rather than the scientist running the simulation. Tho simulation knows what codes, data, software libraries, and versions thereof it is drawing together. All of these pieces of information become documented in the electronic notebook. The electronic notebook is designed with and uses the extensible Markup Language (XML). XML facilitates the representation, storage, interchange, and further use of the documented information.

  9. An electronic notebook for physical system simulation

    NASA Astrophysics Data System (ADS)

    Kelsey, Robert L.

    2003-09-01

    A scientist who sets up and runs experiments typically keeps notes of this process in a lab notebook. A scientist who runs computer simulations should be no different. Experiments and simulations both require a set-up process which should be documented along with the results of the experiment or simulation. The documentation is important for knowing and understanding what was attempted, what took place, and how to reproduce it in the future. Modern simulations of physical systems have become more complex due in part to larger computational resources and increased understanding of physical systems. These simulations may be performed by combining the results from multiple computer codes. The machines that these simulations are executed on are often massively parallel/distributed systems. The output result of one of these simulations can be a terabyte of data and can require months of computing. All of these things contribute to the difficulty of keeping a useful record of the process of setting up and executing a simulation for a physical system. An electronic notebook for physical system simulations has been designed to help document the set up and execution process. Much of the documenting is done automatically by the simulation rather than the scientist running the simulation. The simulation knows what codes, data, software libraries, and versions thereof it is drawing together. All of these pieces of information become documented in the electronic notebook. The electronic notebook is designed with and uses the eXtensible Markup Language (XML). XML facilitates the representation, storage, interchange, and further use of the documented information.

  10. Simulation, Design Abstraction, and SystemC

    ERIC Educational Resources Information Center

    Harcourt, Ed

    2007-01-01

    SystemC is a system-level design and simulation language based on C++. We've been using SystemC for computer organization and design projects for the past several years. Because SystemC is embedded in C++ it contains the powerful abstraction mechanisms of C++ not found in traditional hardware description languages, such as support for…

  11. Simulating Rain Fade In A Communication System

    NASA Technical Reports Server (NTRS)

    Shalkhauser, Kurt A.; Nagy, Lawrence A.; Svoboda, James K.

    1994-01-01

    Automated, computer-controlled assembly of electronic equipment developed for use in simulation testing of downlink portion of Earth/satellite microwave digital communication system. Designed to show effects upon performance of system of rain-induced fading in received signal and increases in transmitted power meant to compensate for rain-induced fading. Design of communication system improved iteratively in response to results of simulations, leading eventually to design ensuring clear, uninterrupted transmission of digital signals.

  12. Characteristics of flight simulator visual systems

    NASA Technical Reports Server (NTRS)

    Statler, I. C. (Editor)

    1981-01-01

    The physical parameters of the flight simulator visual system that characterize the system and determine its fidelity are identified and defined. The characteristics of visual simulation systems are discussed in terms of the basic categories of spatial, energy, and temporal properties corresponding to the three fundamental quantities of length, mass, and time. Each of these parameters are further addressed in relation to its effect, its appropriate units or descriptors, methods of measurement, and its use or importance to image quality.

  13. Quantum Simulation for Open-System Dynamics

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Sheng; de Oliveira, Marcos Cesar; Berry, Dominic; Sanders, Barry

    2013-03-01

    Simulations are essential for predicting and explaining properties of physical and mathematical systems yet so far have been restricted to classical and closed quantum systems. Although forays have been made into open-system quantum simulation, the strict algorithmic aspect has not been explored yet is necessary to account fully for resource consumption to deliver bounded-error answers to computational questions. An open-system quantum simulator would encompass classical and closed-system simulation and also solve outstanding problems concerning, e.g. dynamical phase transitions in non-equilibrium systems, establishing long-range order via dissipation, verifying the simulatability of open-system dynamics on a quantum Turing machine. We construct an efficient autonomous algorithm for designing an efficient quantum circuit to simulate many-body open-system dynamics described by a local Hamiltonian plus decoherence due to separate baths for each particle. The execution time and number of gates for the quantum simulator both scale polynomially with the system size. DSW funded by USARO. MCO funded by AITF and Brazilian agencies CNPq and FAPESP through Instituto Nacional de Ciencia e Tecnologia-Informacao Quantica (INCT-IQ). DWB funded by ARC Future Fellowship (FT100100761). BCS funded by AITF, CIFAR, NSERC and USARO.

  14. Computer simulation of breathing systems for divers

    SciTech Connect

    Sexton, P.G.; Nuckols, M.L.

    1983-02-01

    A powerful new tool for the analysis and design of underwater breathing gas systems is being developed. A versatile computer simulator is described which makes possible the modular ''construction'' of any conceivable breathing gas system from computer memory-resident components. The analysis of a typical breathing gas system is demonstrated using this simulation technique, and the effects of system modifications on performance of the breathing system are shown. This modeling technique will ultimately serve as the foundation for a proposed breathing system simulator under development by the Navy. The marriage of this computer modeling technique with an interactive graphics system will provide the designer with an efficient, cost-effective tool for the development of new and improved diving systems.

  15. Solar simulator for concentrator photovoltaic systems.

    PubMed

    Domínguez, César; Antón, Ignacio; Sala, Gabriel

    2008-09-15

    A solar simulator for measuring performance of large area concentrator photovoltaic (CPV) modules is presented. Its illumination system is based on a Xenon flash light and a large area collimator mirror, which simulates natural sun light. Quality requirements imposed by the CPV systems have been characterized: irradiance level and uniformity at the receiver, light collimation and spectral distribution. The simulator allows indoor fast and cost-effective performance characterization and classification of CPV systems at the production line as well as module rating carried out by laboratories. PMID:18795026

  16. Solar simulator for concentrator photovoltaic systems.

    PubMed

    Domínguez, César; Antón, Ignacio; Sala, Gabriel

    2008-09-15

    A solar simulator for measuring performance of large area concentrator photovoltaic (CPV) modules is presented. Its illumination system is based on a Xenon flash light and a large area collimator mirror, which simulates natural sun light. Quality requirements imposed by the CPV systems have been characterized: irradiance level and uniformity at the receiver, light collimation and spectral distribution. The simulator allows indoor fast and cost-effective performance characterization and classification of CPV systems at the production line as well as module rating carried out by laboratories.

  17. ROBOSIM, a simulator for robotic systems

    NASA Technical Reports Server (NTRS)

    Hinman, Elaine M.; Fernandez, Ken; Cook, George E.

    1991-01-01

    ROBOSIM, a simulator for robotic systems, was developed by NASA to aid in the rapid prototyping of automation. ROBOSIM has allowed the development of improved robotic systems concepts for both earth-based and proposed on-orbit applications while significantly reducing development costs. In a cooperative effort with an area university, ROBOSIM was further developed for use in the classroom as a safe and cost-effective way of allowing students to study robotic systems. Students have used ROBOSIM to study existing robotic systems and systems which they have designed in the classroom. Since an advanced simulator/trainer of this type is beneficial not only to NASA projects and programs but industry and academia as well, NASA is in the process of developing this technology for wider public use. An update on the simulators's new application areas, the improvements made to the simulator's design, and current efforts to ensure the timely transfer of this technology are presented.

  18. Ultra-High Temperature Metallic Seal/Energizer Development for Aero Propulsion and Gas Turbine Applications

    NASA Technical Reports Server (NTRS)

    Cornett, Ken; Newman, Jesse; Datta, Amit

    2009-01-01

    The industry is requiring seals to operate at higher and higher temperatures. Traditional static seal designs and materials experience stress relaxation, losing their ability to maintain contact with moving flanges. Ultra High Temperature seal development program is a multiphase program with incremental increases in seal operating temperatures.

  19. High Temperature Metallic Seal Development For Aero Propulsion and Gas Turbine Applications

    NASA Technical Reports Server (NTRS)

    More, Greg; Datta, Amit

    2006-01-01

    A viewgraph presentation on metallic high temperature static seal development at NASA for gas turbine applications is shown. The topics include: 1) High Temperature Static Seal Development; 2) Program Review; 3) Phase IV Innovative Seal with Blade Alloy Spring; 4) Spring Design; 5) Phase IV: Innovative Seal with Blade Alloy Spring; 6) PHase IV: Testing Results; 7) Seal Seating Load; 8) Spring Seal Manufacturing; and 9) Other Applications for HIgh Temperature Spring Design

  20. High Temperature Metallic Seal/Energizer Development for Aero Propulsion and Gas Turbine Applications

    NASA Technical Reports Server (NTRS)

    More, Greg; Datta, Amit; Cornett, Ken

    2007-01-01

    The Ultra High Temperature seal program has successfully progressed and developed a high temperature static seal solution. The third prototype has successfully combined the first and second prototypes high performance capabilities in a commercially viable solution. Prototype II and Prototype III are viable solutions: Prototype II offers flexible load tune ability and seating load adjustment and Prototype III offers commercial viability for continuous hoop seals.

  1. High-Fidelity Full System Simulations

    NASA Technical Reports Server (NTRS)

    Lytle, John K.

    2004-01-01

    High-fidelity full system simulations have the potential for revolutionizing the way complex systems, such as propulsion systems for aerospace vehicles, are designed, developed, manufactured, and operated. Significant time and cost savings will result from simulations that will resolve deleterious component interactions early in the design process. In addition, innovative new system configurations will result from the use of new tools that enable designers to challenge traditional rules and practices. The major challenges to developing and implementing high-fidelity systems simulations are in reducing the time and effort required to build, execute, and analyze data for the high complex simulations. In addition, large scale testing with unique instrumentation is required to validate the simulations. The solution to these problems reside in the application of advanced information technologies to assist the user to effectively manage, process, and synthesize the vast amount of data. The following presentation describes in more detail the benefits of high-fidelity full system simulations, the challenges to developing and implementing large scale simulations, and one approach that is being followed by the NASA Glenn Research Center to overcome these challenges. In addition, topics for discussion by the panel and audience are suggested.

  2. Simulation of large systems with neural networks

    SciTech Connect

    Paez, T.L.

    1994-09-01

    Artificial neural networks (ANNs) have been shown capable of simulating the behavior of complex, nonlinear, systems, including structural systems. Under certain circumstances, it is desirable to simulate structures that are analyzed with the finite element method. For example, when we perform a probabilistic analysis with the Monte Carlo method, we usually perform numerous (hundreds or thousands of) repetitions of a response simulation with different input and system parameters to estimate the chance of specific response behaviors. In such applications, efficiency in computation of response is critical, and response simulation with ANNs can be valuable. However, finite element analyses of complex systems involve the use of models with tens or hundreds of thousands of degrees of freedom, and ANNs are practically limited to simulations that involve far fewer variables. This paper develops a technique for reducing the amount of information required to characterize the response of a general structure. We show how the reduced information can be used to train a recurrent ANN. Then the trained ANN can be used to simulate the reduced behavior of the original system, and the reduction transformation can be inverted to provide a simulation of the original system. A numerical example is presented.

  3. Particle simulation of plasmas and stellar systems

    SciTech Connect

    Tajima, T.; Clark, A.; Craddock, G.G.; Gilden, D.L.; Leung, W.K.; Li, Y.M.; Robertson, J.A.; Saltzman, B.J.

    1985-04-01

    A computational technique is introduced which allows the student and researcher an opportunity to observe the physical behavior of a class of many-body systems. A series of examples is offered which illustrates the diversity of problems that may be studied using particle simulation. These simulations were in fact assigned as homework in a course on computational physics.

  4. Using Expert Systems To Build Cognitive Simulations.

    ERIC Educational Resources Information Center

    Jonassen, David H.; Wang, Sherwood

    2003-01-01

    Cognitive simulations are runnable computer programs for modeling human cognitive activities. A case study is reported where expert systems were used as a formalism for modeling metacognitive processes in a seminar. Building cognitive simulations engages intensive introspection, ownership and meaning making in learners who build them. (Author/AEF)

  5. The Canadian Hospital Executive Simulation System (CHESS).

    PubMed

    Pink, G H; Knotts, U A; Parrish, L G; Shields, C A

    1991-01-01

    The Canadian Hospital Executive Simulation System (CHESS) is a computer-based management decision-making game designed specifically for Canadian hospital managers. The paper begins with an introduction on the development of business and health services industry-specific simulation games. An overview of CHESS is provided, along with a description of its development and a discussion of its educational benefits. PMID:10109530

  6. Weightlessness simulation system and process

    NASA Technical Reports Server (NTRS)

    Vykukal, Hubert C. (Inventor)

    1987-01-01

    A weightlessness simulator has a chamber and a suit in the chamber. O-rings and valves hermetically seal the chamber. A vacuum pump connected to the chamber establishes a pressure in the chamber less than atmospheric pressure. A water supply tank and water supply line supply a body of water to the chamber as a result of partial vacuum created in the chamber. In use, an astronaut enters the pressure suit through a port, which remains open to ambient atmosphere, thus supplying air to the astronaut during use. The pressure less than atmospheric pressure in the chamber is chosen so that the pressure differential from the inside to the outside of the suit corresponds to the pressure differential with the suit in outer space.

  7. Teaching Environmental Systems Modelling Using Computer Simulation.

    ERIC Educational Resources Information Center

    Moffatt, Ian

    1986-01-01

    A computer modeling course in environmental systems and dynamics is presented. The course teaches senior undergraduates to analyze a system of interest, construct a system flow chart, and write computer programs to simulate real world environmental processes. An example is presented along with a course evaluation, figures, tables, and references.…

  8. Colorimetric calibration of coupled infrared simulation system

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Fei, Jindong; Gao, Yang; Du, Jian

    2015-10-01

    In order to test 2-color infrared sensors, a coupled infrared simulation system can generate radiometric outputs with wavelengths that range from less than 3 microns to more than 12 microns. There are two channels in the coupled simulation system, optically combined by a diachronic beam combiner. Each channel has an infrared blackbody, a filter, a diaphragm, and diaphragm-motors. The system is projected to the sensor under testing by a collimator. This makes it difficult to calibrate the system with only one-band thermal imager. Errors will be caused in the radiance levels measured by the narrow band thermal imager. This paper describes colorimetric temperature measurement techniques that have been developed to perform radiometric calibrations of these infrared simulation systems above. The calibration system consists of two infrared thermal imagers; one is operated at the wavelength range of MW-IR, and the other at the range of LW-IR.

  9. Computer simulator for a mobile telephone system

    NASA Technical Reports Server (NTRS)

    Schilling, D. L.

    1981-01-01

    A software simulator was developed to assist NASA in the design of the land mobile satellite service. Structured programming techniques were used by developing the algorithm using an ALCOL-like pseudo language and then encoding the algorithm into FORTRAN 4. The basic input data to the system is a sine wave signal although future plans call for actual sampled voice as the input signal. The simulator is capable of studying all the possible combinations of types and modes of calls through the use of five communication scenarios: single hop systems; double hop, signal gateway system; double hop, double gateway system; mobile to wireline system; and wireline to mobile system. The transmitter, fading channel, and interference source simulation are also discussed.

  10. The Australian Computational Earth Systems Simulator

    NASA Astrophysics Data System (ADS)

    Mora, P.; Muhlhaus, H.; Lister, G.; Dyskin, A.; Place, D.; Appelbe, B.; Nimmervoll, N.; Abramson, D.

    2001-12-01

    Numerical simulation of the physics and dynamics of the entire earth system offers an outstanding opportunity for advancing earth system science and technology but represents a major challenge due to the range of scales and physical processes involved, as well as the magnitude of the software engineering effort required. However, new simulation and computer technologies are bringing this objective within reach. Under a special competitive national funding scheme to establish new Major National Research Facilities (MNRF), the Australian government together with a consortium of Universities and research institutions have funded construction of the Australian Computational Earth Systems Simulator (ACcESS). The Simulator or computational virtual earth will provide the research infrastructure to the Australian earth systems science community required for simulations of dynamical earth processes at scales ranging from microscopic to global. It will consist of thematic supercomputer infrastructure and an earth systems simulation software system. The Simulator models and software will be constructed over a five year period by a multi-disciplinary team of computational scientists, mathematicians, earth scientists, civil engineers and software engineers. The construction team will integrate numerical simulation models (3D discrete elements/lattice solid model, particle-in-cell large deformation finite-element method, stress reconstruction models, multi-scale continuum models etc) with geophysical, geological and tectonic models, through advanced software engineering and visualization technologies. When fully constructed, the Simulator aims to provide the software and hardware infrastructure needed to model solid earth phenomena including global scale dynamics and mineralisation processes, crustal scale processes including plate tectonics, mountain building, interacting fault system dynamics, and micro-scale processes that control the geological, physical and dynamic

  11. Numerical Propulsion System Simulation for Space Transportation

    NASA Technical Reports Server (NTRS)

    Owen, Karl

    2000-01-01

    Current system simulations are mature, difficult to modify, and poorly documented. Probabilistic life prediction techniques for space applications are in their early application stage. Many parts of the full system, variable fidelity simulation, have been demonstrated individually or technology is available from aeronautical applications. A 20% reduction in time to design with improvements in performance and risk reduction is anticipated. GRC software development will proceed with similar development efforts in aeronautical simulations. Where appropriate, parallel efforts will be encouraged/tracked in high risk areas until success is assured.

  12. Towards Flexible Exascale Stream Processing System Simulation

    SciTech Connect

    Li, Cheng-Hong; Nair, Ravi; Ohba, Noboyuki; Shvadron, Uzi; Zaks, Ayal; Schenfeld, Eugen

    2012-01-01

    Stream processing is an important emerging computational model for performing complex operations on and across multi-source, high-volume, unpredictable dataflows. We present Flow, a platform for parallel and distributed stream processing system simulation that provides a flexible modeling environment for analyzing stream processing applications. The Flow stream processing system simulator is a high-performance, scalable simulator that automatically parallelizes chunks of the model space and incurs near-zero synchronization overhead for acyclic stream application graphs. We show promising parallel and distributed event rates exceeding 149 million events per second on a cluster with 512 processor cores.

  13. Another Program Simulates A Modular Manufacturing System

    NASA Technical Reports Server (NTRS)

    Schroer, Bernard J.; Wang, Jian

    1996-01-01

    SSE5 computer program provides simulation environment for modeling manufacturing systems containing relatively small numbers of stations and operators. Designed to simulate manufacturing of apparel, also used in other manufacturing domains. Valuable for small or medium-size firms, including those lacking expertise to develop detailed mathematical models or have only minimal knowledge in describing manufacturing systems and in analyzing results of simulations on mathematical models. Two other programs available bundled together as SSE (MFS-26245). Each program models slightly different manufacturing scenario. Written in Turbo C v2.0 for IBM PC-series and compatible computers running MS-DOS and successfully compiled using Turbo C++ v3.0.

  14. Electric-Power System Simulator

    NASA Technical Reports Server (NTRS)

    Caldwell, R. W.; Grumm, R. L.; Biedebach, B. L.

    1984-01-01

    Shows different combinations of generation, storage, and load components: display, video monitor with keyboard input to microprocessor, and video monitor for display of load curves and power generation. Planning tool for electric utilities, regulatory agencies, and laymen in understanding basics of electric-power systems operation.

  15. Communication Simulations for Power System Applications

    SciTech Connect

    Fuller, Jason C.; Ciraci, Selim; Daily, Jeffrey A.; Fisher, Andrew R.; Hauer, Matthew L.

    2013-05-29

    New smart grid technologies and concepts, such as dynamic pricing, demand response, dynamic state estimation, and wide area monitoring, protection, and control, are expected to require considerable communication resources. As the cost of retrofit can be high, future power grids will require the integration of high-speed, secure connections with legacy communication systems, while still providing adequate system control and security. While considerable work has been performed to create co-simulators for the power domain with load models and market operations, limited work has been performed in integrating communications directly into a power domain solver. The simulation of communication and power systems will become more important as the two systems become more inter-related. This paper will discuss ongoing work at Pacific Northwest National Laboratory to create a flexible, high-speed power and communication system co-simulator for smart grid applications. The framework for the software will be described, including architecture considerations for modular, high performance computing and large-scale scalability (serialization, load balancing, partitioning, cross-platform support, etc.). The current simulator supports the ns-3 (telecommunications) and GridLAB-D (distribution systems) simulators. Ongoing and future work will be described, including planned future expansions for a traditional transmission solver. A test case using the co-simulator, utilizing a transactive demand response system created for the Olympic Peninsula and AEP gridSMART demonstrations, requiring two-way communication between distributed and centralized market devices, will be used to demonstrate the value and intended purpose of the co-simulation environment.

  16. Simulation and intelligent vehicle highway systems

    SciTech Connect

    Rathi, A.K. ); Santiago, A.J. )

    1992-01-01

    Intelligent Vehicle Highway Systems (IVHS) is based on the premise of using advanced technologies in telecommunication, electronics, and computers to improve the nature and quality of highway travel while making it safer and more efficient. The safety benefits of the IVHS systems are unquestioned; however, there are different levels of optimism about the operational benefits of these systems. While there is a broad consensus that IVHS can improve the flow of traffic, and thus mobility, currently there is very limited empirical evidence or analytical basis to support this optimism. The lack of analytical framework for design, analysis, and evaluation of IVHS concepts will continue to fuel the debate between the skeptics and the advocates of IVHS. Computer simulation is likely to play a major role in the analysis and assessment of the IVHS technologies. In this paper, we attempt to identify the simulation modelling needs to support the IVHS functional areas dealing with traffic flow on highway networks. The paper outlines the envisioned IVHS operational environment. Functional requirements for the simulation modelling system that could be used to support the development and testing of IVHS concepts, namely Advanced Traffic Management Systems (ATMS) and Advanced Traveller Information Systems (ATIS), are defined. Simulation modelling research and development needs to support the design and evaluations of IVHS concepts are described. The paper concludes by presenting on-going work on the traffic simulation models at the Oak Ridge National Laboratory.

  17. Simulation and intelligent vehicle highway systems

    SciTech Connect

    Rathi, A.K.; Santiago, A.J.

    1992-09-01

    Intelligent Vehicle Highway Systems (IVHS) is based on the premise of using advanced technologies in telecommunication, electronics, and computers to improve the nature and quality of highway travel while making it safer and more efficient. The safety benefits of the IVHS systems are unquestioned; however, there are different levels of optimism about the operational benefits of these systems. While there is a broad consensus that IVHS can improve the flow of traffic, and thus mobility, currently there is very limited empirical evidence or analytical basis to support this optimism. The lack of analytical framework for design, analysis, and evaluation of IVHS concepts will continue to fuel the debate between the skeptics and the advocates of IVHS. Computer simulation is likely to play a major role in the analysis and assessment of the IVHS technologies. In this paper, we attempt to identify the simulation modelling needs to support the IVHS functional areas dealing with traffic flow on highway networks. The paper outlines the envisioned IVHS operational environment. Functional requirements for the simulation modelling system that could be used to support the development and testing of IVHS concepts, namely Advanced Traffic Management Systems (ATMS) and Advanced Traveller Information Systems (ATIS), are defined. Simulation modelling research and development needs to support the design and evaluations of IVHS concepts are described. The paper concludes by presenting on-going work on the traffic simulation models at the Oak Ridge National Laboratory.

  18. Simulation framework for intelligent transportation systems

    SciTech Connect

    Ewing, T.; Doss, E.; Hanebutte, U.; Tentner, A.

    1996-10-01

    A simulation framework has been developed for a large-scale, comprehensive, scaleable simulation of an Intelligent Transportation System (ITS). The simulator is designed for running on parallel computers and distributed (networked) computer systems, but can run on standalone workstations for smaller simulations. The simulator currently models instrumented smart vehicles with in-vehicle navigation units capable of optimal route planning and Traffic Management Centers (TMC). The TMC has probe vehicle tracking capabilities (display position and attributes of instrumented vehicles), and can provide two-way interaction with traffic to provide advisories and link times. Both the in-vehicle navigation module and the TMC feature detailed graphical user interfaces to support human-factors studies. Realistic modeling of variations of the posted driving speed are based on human factors studies that take into consideration weather, road conditions, driver personality and behavior, and vehicle type. The prototype has been developed on a distributed system of networked UNIX computers but is designed to run on parallel computers, such as ANL`s IBM SP-2, for large-scale problems. A novel feature of the approach is that vehicles are represented by autonomous computer processes which exchange messages with other processes. The vehicles have a behavior model which governs route selection and driving behavior, and can react to external traffic events much like real vehicles. With this approach, the simulation is scaleable to take advantage of emerging massively parallel processor (MPP) systems.

  19. An Open Source Simulation System

    NASA Technical Reports Server (NTRS)

    Slack, Thomas

    2005-01-01

    An investigation into the current state of the art of open source real time programming practices. This document includes what technologies are available, how easy is it to obtain, configure, and use them, and some performance measures done on the different systems. A matrix of vendors and their products is included as part of this investigation, but this is not an exhaustive list, and represents only a snapshot of time in a field that is changing rapidly. Specifically, there are three approaches investigated: 1. Completely open source on generic hardware, downloaded from the net. 2. Open source packaged by a vender and provided as free evaluation copy. 3. Proprietary hardware with pre-loaded proprietary source available software provided by the vender as for our evaluation.

  20. Observing System Simulation Experiments: An Overview

    NASA Technical Reports Server (NTRS)

    Prive, Nikki C.; Errico, Ronald M.

    2016-01-01

    An overview of Observing System Simulation Experiments (OSSEs) will be given, with focus on calibration and validation of OSSE frameworks. Pitfalls and practice will be discussed, including observation error characteristics, incestuousness, and experimental design. The potential use of OSSEs for investigation of the behaviour of data assimilation systems will be explored, including some results from experiments using the NASAGMAO OSSE.

  1. Space shuttle visual simulation system design study

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The current and near-future state-of-the-art in visual simulation equipment technology is related to the requirements of the space shuttle visual system. Image source, image sensing, and displays are analyzed on a subsystem basis, and the principal conclusions are used in the formulation of a recommended baseline visual system. Perceptibility and visibility are also analyzed.

  2. Thermal enclosure system functional simulation user's manual

    NASA Technical Reports Server (NTRS)

    Morris, A. Terry

    1994-01-01

    A form and function simulation of the thermal enclosure system (TES) for a microgravity protein crystal growth experiment has been developed as part of an investigation of the benefits and limitations of intravehicular telerobotics to aid in microgravity science and production. A user can specify the time, temperature, and sample rate profile for a given experiment, and menu options and status are presented on an LCD display. This report describes the features and operational procedures for the functional simulation.

  3. Exploring team avionics systems by simulation

    NASA Technical Reports Server (NTRS)

    Brent, G. A.; Mccalla, T. M., Jr.

    1978-01-01

    Configurations of software and hardware in a no-critical-element team architecture are under study for future general aviation aircraft avionics. The team integrated avionics system, based on microprocessors, can monitor and partially interpret all flight instrument data, engine parameters, and navigation information faster than a human pilot. Simulation programs based on an event-oriented simulation language are being used to design team architectures.

  4. AMCOM RDEC ladar HWIL simulation system development

    NASA Astrophysics Data System (ADS)

    Kim, Hajin J.; Mobley, Scottie B.; Buford, James A., Jr.

    2003-09-01

    Hardware-in-the-loop (HWIL) testing has, for many years, been an integral part of the modeling and simulation efforts at the U.S. Army Aviation and Missile Command"s (AMCOM) Aviation and Missile Research, Engineering, and Development Center (AMRDEC). AMCOM"s history includes the development, characterization, and implementation of several unique technologies for the creation of synthetic environments in the visible, infrared, and radio frequency spectral regions and AMCOM has continued significant efforts in these areas. This paper describes recent advancements at AMCOM"s Advanced Simulation Center (ASC) and concentrates on Ladar HWIL simulation system development.

  5. River system environmental modeling and simulation methodology

    SciTech Connect

    Rao, N.B.

    1981-01-01

    Several computer models have been built to examine pollution in rivers. However, the current state of the art in this field emphasizes problem solving using specific programs. A general methodology for building and simulating models of river systems is lacking. Thus, the purpose of this research was to develop a methodology which can be used to conceptualize, visualize, construct and analyze using simulation, models of pollution in river systems. The conceptualization and visualization of these models was facilitated through a network representation. The implementation of the models was accomplished using the capabilities of an existing simulation language, GASP V. The methodology also provides data management facilities for model outputs through the use of the Simulation Data Language (SDL), and high quality plotting facilities through the use of the graphics package DISSPLA (Display Integrated Software System and Plotting Language). Using this methodology, a river system is modeled as consisting of certain elements, namely reaches, junctions, dams, reservoirs, withdrawals and pollutant sources. All these elements of the river system are described in a standard form which has been implemented on a computer. This model, when executed, produces spatial and temporal distributions of the pollutants in the river system. Furthermore, these outputs can be stored in a database and used to produce high quality plots. The result of this research is a methodology for building, implementing and examining the results of models of pollution in river systems.

  6. Multipurpose simulation systems for regional development forecasting

    SciTech Connect

    Kostina, N.I.

    1995-09-01

    We examine the development of automaton-modeling multipurpose simulation systems as an efficient form of simulation software for MIS. Such systems constitute a single problem-oriented package of applications based on a general simulation model, which is equipped with a task source language, interaction tools, file management tools, and an output document editor. The simulation models are described by the method of probabilistic-automaton modeling, which ensures standard representation of models and standardization of the modeling algorithm. Examples of such systems include the demographic forecasting system DEPROG, the VOKON system for assessing the quality of consumer services in terms of free time, and the SONET system for servicing partially accessible customers. The development of computer-aided systems for production and economic control is now moving to the second state, namely operationalization of optimization and forecasting problems, whose solution may account for the main economic effect of MIS. Computation and information problems, which were the main focus of the first stage of MIS development, are thus acquiring the role of a source of information for optimization and forecasting problems in addition to their direct contribution to preparation and analysis of current production and economic information.

  7. 2000 Numerical Propulsion System Simulation Review

    NASA Technical Reports Server (NTRS)

    Lytle, John; Follen, Greg; Naiman, Cynthia; Veres, Joseph; Owen, Karl; Lopez, Isaac

    2001-01-01

    The technologies necessary to enable detailed numerical simulations of complete propulsion systems are being developed at the NASA Glenn Research Center in cooperation with industry, academia, and other government agencies. Large scale, detailed simulations will be of great value to the nation because they eliminate some of the costly testing required to develop and certify advanced propulsion systems. In addition, time and cost savings will be achieved by enabling design details to be evaluated early in the development process before a commitment is made to a specific design. This concept is called the Numerical Propulsion System Simulation (NPSS). NPSS consists of three main elements: (1) engineering models that enable multidisciplinary analysis of large subsystems and systems at various levels of detail, (2) a simulation environment that maximizes designer productivity, and (3) a cost-effective. high-performance computing platform. A fundamental requirement of the concept is that the simulations must be capable of overnight execution on easily accessible computing platforms. This will greatly facilitate the use of large-scale simulations in a design environment. This paper describes the current status of the NPSS with specific emphasis on the progress made over the past year on air breathing propulsion applications. Major accomplishments include the first formal release of the NPSS object-oriented architecture (NPSS Version 1) and the demonstration of a one order of magnitude reduction in computing cost-to-performance ratio using a cluster of personal computers. The paper also describes the future NPSS milestones, which include the simulation of space transportation propulsion systems in response to increased emphasis on safe, low cost access to space within NASA'S Aerospace Technology Enterprise. In addition, the paper contains a summary of the feedback received from industry partners on the fiscal year 1999 effort and the actions taken over the past year to

  8. 2001 Numerical Propulsion System Simulation Review

    NASA Technical Reports Server (NTRS)

    Lytle, John; Follen, Gregory; Naiman, Cynthia; Veres, Joseph; Owen, Karl; Lopez, Isaac

    2002-01-01

    The technologies necessary to enable detailed numerical simulations of complete propulsion systems are being developed at the NASA Glenn Research Center in cooperation with industry, academia and other government agencies. Large scale, detailed simulations will be of great value to the nation because they eliminate some of the costly testing required to develop and certify advanced propulsion systems. In addition, time and cost savings will be achieved by enabling design details to be evaluated early in the development process before a commitment is made to a specific design. This concept is called the Numerical Propulsion System Simulation (NPSS). NPSS consists of three main elements: (1) engineering models that enable multidisciplinary analysis of large subsystems and systems at various levels of detail, (2) a simulation environment that maximizes designer productivity, and (3) a cost-effective, high-performance computing platform. A fundamental requirement of the concept is that the simulations must be capable of overnight execution on easily accessible computing platforms. This will greatly facilitate the use of large-scale simulations in a design environment. This paper describes the current status of the NPSS with specific emphasis on the progress made over the past year on air breathing propulsion applications. Major accomplishments include the first formal release of the NPSS object-oriented architecture (NPSS Version 1) and the demonstration of a one order of magnitude reduction in computing cost-to-performance ratio using a cluster of personal computers. The paper also describes the future NPSS milestones, which include the simulation of space transportation propulsion systems in response to increased emphasis on safe, low cost access to space within NASA's Aerospace Technology Enterprise. In addition, the paper contains a summary of the feedback received from industry partners on the fiscal year 2000 effort and the actions taken over the past year to

  9. Spatial Aspects in Biological System Simulations

    PubMed Central

    Resat, Haluk; Costa, Michelle N.; Shankaran, Harish

    2012-01-01

    Mathematical models of the dynamical properties of biological systems aim to improve our understanding of the studied system with the ultimate goal of being able to predict system responses in the absence of experimentation. Despite the enormous advances that have been made in biological modeling and simulation, the inherently multiscale character of biological systems and the stochasticity of biological processes continue to present significant computational and conceptual challenges. Biological systems often consist of well-organized structural hierarchies, which inevitably lead to multiscale problems. This chapter introduces and discusses the advantages and shortcomings of several simulation methods that are being used by the scientific community to investigate the spatiotemporal properties of model biological systems. We first describe the foundations of the methods and then describe their relevance and possible application areas with illustrative examples from our own research. Possible ways to address the encountered computational difficulties are also discussed. PMID:21187236

  10. Multidisciplinary propulsion simulation using the numerical propulsion system simulator (NPSS)

    NASA Technical Reports Server (NTRS)

    Claus, Russel W.

    1994-01-01

    Implementing new technology in aerospace propulsion systems is becoming prohibitively expensive. One of the major contributions to the high cost is the need to perform many large scale system tests. The traditional design analysis procedure decomposes the engine into isolated components and focuses attention on each single physical discipline (e.g., fluid for structural dynamics). Consequently, the interactions that naturally occur between components and disciplines can be masked by the limited interactions that occur between individuals or teams doing the design and must be uncovered during expensive engine testing. This overview will discuss a cooperative effort of NASA, industry, and universities to integrate disciplines, components, and high performance computing into a Numerical propulsion System Simulator (NPSS).

  11. Aid For Simulating Digital Flight Control Systems

    NASA Technical Reports Server (NTRS)

    Hartman, Richard M.

    1991-01-01

    DIVERS translator is computer program to convert descriptions of digital flight-control systems (DFCS) into computer program. Language developed to represent design charts of DFCS. Translator converts DIVERS source code into easily transportable language, while minimizing probability that results are affected by interpretation of programmer. Final translated program used as standard of comparison to verify operation of actual flight-control systems. Applicable to simulation of other control systems; for example, electrical circuits and logic processes. Written in C.

  12. Simulating failures on large-scale systems.

    SciTech Connect

    Desai, N.; Lusk, E.; Buettner, D.; Cherry, A.; Voran, T.; Univ. of Colorado

    2008-09-01

    Developing fault management mechanisms is a difficult task because of the unpredictable nature of failures. In this paper, we present a fault simulation framework for Blue Gene/P systems implemented as a part of the Cobalt resource manager. The primary goal of this framework is to support system software development. We also present a hardware diagnostic system that we have implemented using this framework.

  13. System Equivalent for Real Time Digital Simulator

    NASA Astrophysics Data System (ADS)

    Lin, Xi

    2011-07-01

    The purpose of this research is to develop a method of making system equivalents for the Real Time Digital Simulator (RTDS), which should enhance its capability of simulating large power systems. The proposed equivalent combines a Frequency Dependent Network Equivalent (FDNE) for the high frequency electromagnetic transients and a Transient Stability Analysis (TSA) type simulation block for the electromechanical transients. The frequency dependent characteristic for FDNE is obtained by curve-fitting frequency domain admittance characteristics using the Vector Fitting method. An approach for approximating the frequency dependent characteristic of large power networks from readily available typical power-flow data is also introduced. A new scheme of incorporating TSA solution in RTDS is proposed. This report shows how the TSA algorithm can be adapted to a real time platform. The validity of this method is confirmed with examples, including the study of a multi in-feed HVDC system based network.

  14. Discrete event simulation of continuous systems

    SciTech Connect

    Nutaro, James J

    2007-01-01

    Computer simulation of a system described by differential equations requires that some element of the system be approximated by discrete quantities. There are two system aspects that can be made discrete; time and state. When time is discrete, the differential equation is approximated by a difference equation (i.e., a discrete time system), and the solution is calculated at fixed points in time. When the state is discrete, the differential equation is approximated by a discrete event system. Events correspond to jumps through the discrete state space of the approximation.

  15. Expert system for scheduling simulation lab sessions

    NASA Technical Reports Server (NTRS)

    Lund, Chet

    1990-01-01

    Implementation and results of an expert system used for scheduling session requests for the Systems Engineering Simulator (SES) laboratory at the NASA Johnson Space Center (JSC) are discussed. Weekly session requests are received from astronaut crew trainers, procedures developers, engineering assessment personnel, software developers, and various others who wish to access the computers, scene generators, and other simulation equipment available to them in the SES lab. The expert system under discussion is comprised of a data acquisition portion - two Pascal programs run on a personal computer - and a CLIPS program installed on a minicomputer. A brief introduction to the SES lab and its scheduling background is given. A general overview of the system is provided, followed by a detailed description of the constraint-reduction process and of the scheduler itself. Results from a ten-week trial period using this approach are discussed. Finally, a summary of the expert system's strengths and shortcomings are provided.

  16. Argonne simulation framework for intelligent transportation systems

    SciTech Connect

    Ewing, T.; Doss, E.; Hanebutte, U.; Canfield, T.; Brown-VanHoozer, A.; Tentner, A.

    1996-04-01

    A simulation framework has been developed which defines a high-level architecture for a large-scale, comprehensive, scalable simulation of an Intelligent Transportation System (ITS). The simulator is designed to run on parallel computers and distributed (networked) computer systems; however, a version for a stand alone workstation is also available. The ITS simulator includes an Expert Driver Model (EDM) of instrumented ``smart`` vehicles with in-vehicle navigation units. The EDM is capable of performing optimal route planning and communicating with Traffic Management Centers (TMC). A dynamic road map data base is sued for optimum route planning, where the data is updated periodically to reflect any changes in road or weather conditions. The TMC has probe vehicle tracking capabilities (display position and attributes of instrumented vehicles), and can provide 2-way interaction with traffic to provide advisories and link times. Both the in-vehicle navigation module and the TMC feature detailed graphical user interfaces that includes human-factors studies to support safety and operational research. Realistic modeling of variations of the posted driving speed are based on human factor studies that take into consideration weather, road conditions, driver`s personality and behavior and vehicle type. The simulator has been developed on a distributed system of networked UNIX computers, but is designed to run on ANL`s IBM SP-X parallel computer system for large scale problems. A novel feature of the developed simulator is that vehicles will be represented by autonomous computer processes, each with a behavior model which performs independent route selection and reacts to external traffic events much like real vehicles. Vehicle processes interact with each other and with ITS components by exchanging messages. With this approach, one will be able to take advantage of emerging massively parallel processor (MPP) systems.

  17. Simulating Astronomical Adaptive Optics Systems Using Yao

    NASA Astrophysics Data System (ADS)

    Rigaut, François; Van Dam, Marcos

    2013-12-01

    Adaptive Optics systems are at the heart of the coming Extremely Large Telescopes generation. Given the importance, complexity and required advances of these systems, being able to simulate them faithfully is key to their success, and thus to the success of the ELTs. The type of systems envisioned to be built for the ELTs cover most of the AO breeds, from NGS AO to multiple guide star Ground Layer, Laser Tomography and Multi-Conjugate AO systems, with typically a few thousand actuators. This represents a large step up from the current generation of AO systems, and accordingly a challenge for existing AO simulation packages. This is especially true as, in the past years, computer power has not been following Moore's law in its most common understanding; CPU clocks are hovering at about 3GHz. Although the use of super computers is a possible solution to run these simulations, being able to use smaller machines has obvious advantages: cost, access, environmental issues. By using optimised code in an already proven AO simulation platform, we were able to run complex ELT AO simulations on very modest machines, including laptops. The platform is YAO. In this paper, we describe YAO, its architecture, its capabilities, the ELT-specific challenges and optimisations, and finally its performance. As an example, execution speed ranges from 5 iterations per second for a 6 LGS 60x60 subapertures Shack-Hartmann Wavefront sensor Laser Tomography AO system (including full physical image formation and detector characteristics) up to over 30 iterations/s for a single NGS AO system.

  18. Participatory ergonomics simulation of hospital work systems: The influence of simulation media on simulation outcome.

    PubMed

    Andersen, Simone Nyholm; Broberg, Ole

    2015-11-01

    Current application of work system simulation in participatory ergonomics (PE) design includes a variety of different simulation media. However, the actual influence of the media attributes on the simulation outcome has received less attention. This study investigates two simulation media: full-scale mock-ups and table-top models. The aim is to compare, how the media attributes of fidelity and affordance influence the ergonomics identification and evaluation in PE design of hospital work systems. The results illustrate, how the full-scale mock-ups' high fidelity of room layout and affordance of tool operation support ergonomics identification and evaluation related to the work system entities space and technologies & tools. The table-top models' high fidelity of function relations and affordance of a helicopter view support ergonomics identification and evaluation related to the entity organization. Furthermore, the study addresses the form of the identified and evaluated conditions, being either identified challenges or tangible design criteria.

  19. Hybrid system modeling, simulation, and visualization: a crane system

    NASA Astrophysics Data System (ADS)

    Hiniduma Udugama Gamage, Sahan S.; Palmer, Patrick R.

    2003-08-01

    Modeling and visualization of a complex hybrid system with different domains of energy flow and signal flow are described in this paper. It is a crane system situated in a barge complete with the load, electrical power, drive and control systems. A dynamically and functionally accurate model of the crane was developed. The implementation is in the freely available software suit of Virtual Test Bed (VTB) for simulation and Visual Extension Engine (VXE) for visualization. The bidirectional interaction of simulator and visualizer is fully utilized in this application. The further challenges confronted in implementing this particular system and any other complex system are discussed and possible solutions are suggested.

  20. Electric System Intra-hour Operation Simulator

    2014-03-07

    ESIOS is a software program developed at Pacific Northwest National Laboratory (PNNL) that performs intra-hour dispatch and automatic generation control (AGC) simulations for electric power system frequency regulation and load/variable generation following. The program dispatches generation resources at minute interval to meet control performance requirements, while incorporating stochastic models of forecast errors and variability with generation, load, interchange and market behaviors. The simulator also contains an operator model that mimics manual actions to adjust resourcemore » dispatch and maintain system reserves. Besides simulating generation fleet intra-hour dispatch, ESIOS can also be used as a test platform for the design and verification of energy storage, demand response, and other technologies helping to accommodate variable generation.« less

  1. Theory and Simulations of Solar System Plasmas

    NASA Technical Reports Server (NTRS)

    Goldstein, Melvyn L.

    2011-01-01

    "Theory and simulations of solar system plasmas" aims to highlight results from microscopic to global scales, achieved by theoretical investigations and numerical simulations of the plasma dynamics in the solar system. The theoretical approach must allow evidencing the universality of the phenomena being considered, whatever the region is where their role is studied; at the Sun, in the solar corona, in the interplanetary space or in planetary magnetospheres. All possible theoretical issues concerning plasma dynamics are welcome, especially those using numerical models and simulations, since these tools are mandatory whenever analytical treatments fail, in particular when complex nonlinear phenomena are at work. Comparative studies for ongoing missions like Cassini, Cluster, Demeter, Stereo, Wind, SDO, Hinode, as well as those preparing future missions and proposals, like, e.g., MMS and Solar Orbiter, are especially encouraged.

  2. LHC RF System Time-Domain Simulation

    SciTech Connect

    Mastorides, T.; Rivetta, C.; /SLAC

    2010-09-14

    Non-linear time-domain simulations have been developed for the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC). These simulations capture the dynamic behavior of the RF station-beam interaction and are structured to reproduce the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They are also a valuable tool for the study of diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Results from these studies and related measurements from PEP-II and LHC have been presented in multiple places. This report presents an example of the time-domain simulation implementation for the LHC.

  3. Numerical simulation of imaging laser radar system

    NASA Astrophysics Data System (ADS)

    Han, Shaokun; Lu, Bo; Jiang, Ming; Liu, Xunliang

    2008-03-01

    Rational and effective design of imaging laser radar systems is the key of imaging laser radar system research. Design must fully consider the interrelationship between various parameters. According to the parameters, choose suitable laser, detector and other components. To use of mathematical modeling and computer simulation is an effective imaging laser radar system design methods. This paper based on the distance equation, using the detection statistical methods, from the laser radar range coverage, detection probability, false-alarm rate, SNR to build the laser radar system mathematical models. In the process of setting up the mathematical models to fully consider the laser, atmosphere, detector and other factors on the performance that is to make the models be able to respond accurately the real situation. Based on this using C# and Matlab designed a simulation software.

  4. Aviation spectral camera infinity target simulation system

    NASA Astrophysics Data System (ADS)

    Liu, Xinyue; Ming, Xing; Liu, Jiu; Guo, Wenji; Lv, Gunbo

    2014-11-01

    With the development of science and technology, the applications of aviation spectral camera becoming more widely. Developing a test system of dynamic target is more important. Aviation spectral camera infinity target simulation system can be used to test the resolution and the modulation transfer function of camera. The construction and work principle of infinity target simulation system were introduced in detail. Dynamic target generator based digital micromirror device (DMD) and required performance of collimation System were analyzed and reported. The dynamic target generator based on DMD had the advantages of replacing image convenient, size small and flexible. According to the requirement of tested camera, by rotating and moving mirror, has completed a full field infinity dynamic target test plan.

  5. Introduction to Observing System Simulation Experiments (OSSEs)

    NASA Technical Reports Server (NTRS)

    Prive, Nikki C.

    2014-01-01

    This presentation gives a brief overview of Observing System Simulation Experiments (OSSEs), including what OSSEs are, and how and why they are performed. The intent is to educate the audience in light of the OSSE-related sections of the Forecast Improvement Act (H.R. 2413).

  6. The systems biology simulation core algorithm

    PubMed Central

    2013-01-01

    Background With the increasing availability of high dimensional time course data for metabolites, genes, and fluxes, the mathematical description of dynamical systems has become an essential aspect of research in systems biology. Models are often encoded in formats such as SBML, whose structure is very complex and difficult to evaluate due to many special cases. Results This article describes an efficient algorithm to solve SBML models that are interpreted in terms of ordinary differential equations. We begin our consideration with a formal representation of the mathematical form of the models and explain all parts of the algorithm in detail, including several preprocessing steps. We provide a flexible reference implementation as part of the Systems Biology Simulation Core Library, a community-driven project providing a large collection of numerical solvers and a sophisticated interface hierarchy for the definition of custom differential equation systems. To demonstrate the capabilities of the new algorithm, it has been tested with the entire SBML Test Suite and all models of BioModels Database. Conclusions The formal description of the mathematics behind the SBML format facilitates the implementation of the algorithm within specifically tailored programs. The reference implementation can be used as a simulation backend for Java™-based programs. Source code, binaries, and documentation can be freely obtained under the terms of the LGPL version 3 from http://simulation-core.sourceforge.net. Feature requests, bug reports, contributions, or any further discussion can be directed to the mailing list simulation-core-development@lists.sourceforge.net. PMID:23826941

  7. Simulations of noise in disordered systems

    SciTech Connect

    Reichhardt, C.; Reichhardt, C. J.

    2003-01-01

    We use particle dynamics simulations to probe the correlations between noise and dynamics in a variety of disordered systems, including super conducting vortices, 2D electron liquid crystals, colloids, domain walls, and granular media. The noise measurements offer an experimentally accessible link to the microscopic dynamics, such as plastic versus elastic flow during transport, and can provide a signature of dynamical reordering transitions in the system. We consider broad and narrow band noise in transport systems, as well as the fluctuations of dislocation density in a system near the melting transition.

  8. Plans for wind energy system simulation

    NASA Technical Reports Server (NTRS)

    Dreier, M. E.

    1978-01-01

    A digital computer code and a special purpose hybrid computer, were introduced. The digital computer program, the Root Perturbation Method or RPM, is an implementation of the classic floquet procedure which circumvents numerical problems associated with the extraction of Floquet roots. The hybrid computer, the Wind Energy System Time domain simulator (WEST), yields real time loads and deformation information essential to design and system stability investigations.

  9. A simulation of data acquisition system for SSC experiments

    SciTech Connect

    Watase, Y.; Ikeda, H.

    1989-04-01

    A simulation on some parts of the data acquisition system was performed using a general purpose simulation language GPSS. Several results of the simulation are discussed for the data acquisition system for the SSC experiment.

  10. The Numerical Propulsion System Simulation: An Overview

    NASA Technical Reports Server (NTRS)

    Lytle, John K.

    2000-01-01

    Advances in computational technology and in physics-based modeling are making large-scale, detailed simulations of complex systems possible within the design environment. For example, the integration of computing, communications, and aerodynamics has reduced the time required to analyze major propulsion system components from days and weeks to minutes and hours. This breakthrough has enabled the detailed simulation of major propulsion system components to become a routine part of designing systems, providing the designer with critical information about the components early in the design process. This paper describes the development of the numerical propulsion system simulation (NPSS), a modular and extensible framework for the integration of multicomponent and multidisciplinary analysis tools using geographically distributed resources such as computing platforms, data bases, and people. The analysis is currently focused on large-scale modeling of complete aircraft engines. This will provide the product developer with a "virtual wind tunnel" that will reduce the number of hardware builds and tests required during the development of advanced aerospace propulsion systems.

  11. Java simulations of embedded control systems.

    PubMed

    Farias, Gonzalo; Cervin, Anton; Arzén, Karl-Erik; Dormido, Sebastián; Esquembre, Francisco

    2010-01-01

    This paper introduces a new Open Source Java library suited for the simulation of embedded control systems. The library is based on the ideas and architecture of TrueTime, a toolbox of Matlab devoted to this topic, and allows Java programmers to simulate the performance of control processes which run in a real time environment. Such simulations can improve considerably the learning and design of multitasking real-time systems. The choice of Java increases considerably the usability of our library, because many educators program already in this language. But also because the library can be easily used by Easy Java Simulations (EJS), a popular modeling and authoring tool that is increasingly used in the field of Control Education. EJS allows instructors, students, and researchers with less programming capabilities to create advanced interactive simulations in Java. The paper describes the ideas, implementation, and sample use of the new library both for pure Java programmers and for EJS users. The JTT library and some examples are online available on http://lab.dia.uned.es/jtt.

  12. Java simulations of embedded control systems.

    PubMed

    Farias, Gonzalo; Cervin, Anton; Arzén, Karl-Erik; Dormido, Sebastián; Esquembre, Francisco

    2010-01-01

    This paper introduces a new Open Source Java library suited for the simulation of embedded control systems. The library is based on the ideas and architecture of TrueTime, a toolbox of Matlab devoted to this topic, and allows Java programmers to simulate the performance of control processes which run in a real time environment. Such simulations can improve considerably the learning and design of multitasking real-time systems. The choice of Java increases considerably the usability of our library, because many educators program already in this language. But also because the library can be easily used by Easy Java Simulations (EJS), a popular modeling and authoring tool that is increasingly used in the field of Control Education. EJS allows instructors, students, and researchers with less programming capabilities to create advanced interactive simulations in Java. The paper describes the ideas, implementation, and sample use of the new library both for pure Java programmers and for EJS users. The JTT library and some examples are online available on http://lab.dia.uned.es/jtt. PMID:22163674

  13. Java Simulations of Embedded Control Systems

    PubMed Central

    Farias, Gonzalo; Cervin, Anton; Årzén, Karl-Erik; Dormido, Sebastián; Esquembre, Francisco

    2010-01-01

    This paper introduces a new Open Source Java library suited for the simulation of embedded control systems. The library is based on the ideas and architecture of TrueTime, a toolbox of Matlab devoted to this topic, and allows Java programmers to simulate the performance of control processes which run in a real time environment. Such simulations can improve considerably the learning and design of multitasking real-time systems. The choice of Java increases considerably the usability of our library, because many educators program already in this language. But also because the library can be easily used by Easy Java Simulations (EJS), a popular modeling and authoring tool that is increasingly used in the field of Control Education. EJS allows instructors, students, and researchers with less programming capabilities to create advanced interactive simulations in Java. The paper describes the ideas, implementation, and sample use of the new library both for pure Java programmers and for EJS users. The JTT library and some examples are online available on http://lab.dia.uned.es/jtt. PMID:22163674

  14. Cassini radar : system concept and simulation results

    NASA Astrophysics Data System (ADS)

    Melacci, P. T.; Orosei, R.; Picardi, G.; Seu, R.

    1998-10-01

    The Cassini mission is an international venture, involving NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI), for the investigation of the Saturn system and, in particular, Titan. The Cassini radar will be able to see through Titan's thick, optically opaque atmosphere, allowing us to better understand the composition and the morphology of its surface, but the interpretation of the results, due to the complex interplay of many different factors determining the radar echo, will not be possible without an extensive modellization of the radar system functioning and of the surface reflectivity. In this paper, a simulator of the multimode Cassini radar will be described, after a brief review of our current knowledge of Titan and a discussion of the contribution of the Cassini radar in answering to currently open questions. Finally, the results of the simulator will be discussed. The simulator has been implemented on a RISC 6000 computer by considering only the active modes of operation, that is altimeter and synthetic aperture radar. In the instrument simulation, strict reference has been made to the present planned sequence of observations and to the radar settings, including burst and single pulse duration, pulse bandwidth, pulse repetition frequency and all other parameters which may be changed, and possibly optimized, according to the operative mode. The observed surfaces are simulated by a facet model, allowing the generation of surfaces with Gaussian or non-Gaussian roughness statistic, together with the possibility of assigning to the surface an average behaviour which can represent, for instance, a flat surface or a crater. The results of the simulation will be discussed, in order to check the analytical evaluations of the models of the average received echoes and of the attainable performances. In conclusion, the simulation results should allow the validation of the theoretical evaluations of the capabilities of microwave instruments, when

  15. Simulation System for Training in Laparoscopic Surgery

    NASA Technical Reports Server (NTRS)

    Basdogan, Cagatay; Ho, Chih-Hao

    2003-01-01

    A computer-based simulation system creates a visual and haptic virtual environment for training a medical practitioner in laparoscopic surgery. Heretofore, it has been common practice to perform training in partial laparoscopic surgical procedures by use of a laparoscopic training box that encloses a pair of laparoscopic tools, objects to be manipulated by the tools, and an endoscopic video camera. However, the surgical procedures simulated by use of a training box are usually poor imitations of the actual ones. The present computer-based system improves training by presenting a more realistic simulated environment to the trainee. The system includes a computer monitor that displays a real-time image of the affected interior region of the patient, showing laparoscopic instruments interacting with organs and tissues, as would be viewed by use of an endoscopic video camera and displayed to a surgeon during a laparoscopic operation. The system also includes laparoscopic tools that the trainee manipulates while observing the image on the computer monitor (see figure). The instrumentation on the tools consists of (1) position and orientation sensors that provide input data for the simulation and (2) actuators that provide force feedback to simulate the contact forces between the tools and tissues. The simulation software includes components that model the geometries of surgical tools, components that model the geometries and physical behaviors of soft tissues, and components that detect collisions between them. Using the measured positions and orientations of the tools, the software detects whether they are in contact with tissues. In the event of contact, the deformations of the tissues and contact forces are computed by use of the geometric and physical models. The image on the computer screen shows tissues deformed accordingly, while the actuators apply the corresponding forces to the distal ends of the tools. For the purpose of demonstration, the system has been set

  16. Parachute system design, analysis, and simulation tool

    SciTech Connect

    Sundberg, W.D.; McBride, D.D.; Gwinn, K.W.; Waye, D.E.; Hailey, C.E.

    1992-01-01

    For over twenty years designers at Sandia National Laboratories have developed various parachute simulation codes to model deployment, inflation, loading, trajectories, aircraft downwash and line sail. In addition to these codes, material property data bases have been acquired. Recently we have initiated project to integrate these codes and data bases into a single software tool entitled SPARSYS (Sandia PARachute SYstem Simulation). We have constructed a graphical user interface as the driver and framework for SPARSYS. In this paper we present a status report on SPARSYS describing progress in developing and incorporating independent modules, in developing an integrated trajectory package, and in developing a materials data base including high-rate-of-strain data.

  17. Simulation of Flywheel Energy Storage System Controls

    NASA Technical Reports Server (NTRS)

    Truong, Long V.; Wolff, Frederick J.; Dravid, Narayan

    2001-01-01

    This paper presents the progress made in the controller design and operation of a flywheel energy storage system. The switching logic for the converter bridge circuit has been redefined to reduce line current harmonics, even at the highest operating speed of the permanent magnet motor-generator. An electromechanical machine model is utilized to simulate charge and discharge operation of the inertial energy in the flywheel. Controlling the magnitude of phase currents regulates the rate of charge and discharge. The resulting improvements are demonstrated by simulation.

  18. Interactive simulation of digital communication systems

    NASA Astrophysics Data System (ADS)

    Modestino, J. W.; Matis, K. R.

    1984-01-01

    In this paper, efforts to develop a comprehensive tool for the digital simulation of a wide variety of point-to-point digital communication systems are described. These efforts have resulted in the interactive communications simulator (ICS), a flexible, graphics-oriented, and highly interactive hardware/software system consisting of a typical minicomputer acting as host to a fast peripheral array processor. This system is presently being employed both to evaluate existing modem performance and to explore new modulation/coding concepts approprate for military, commercial, and space applications. A detailed functional description of the ICS is provided together with pertinent software considerations. An outline of existinig ICS capabilities is presented and illustrated through typical graphical output. A discussion of channel modeling considerations is provided. The use of the ICS in the overall design of receiver structures for impulsive noise channels will be illustrated.

  19. Simulating Complex Window Systems using BSDF Data

    SciTech Connect

    Konstantoglou, Maria; Jonsson, Jacob; Lee, Eleanor

    2009-06-22

    Nowadays, virtual models are commonly used to evaluate the performance of conventional window systems. Complex fenestration systems can be difficult to simulate accurately not only because of their geometry but also because of their optical properties that scatter light in an unpredictable manner. Bi-directional Scattering Distribution Functions (BSDF) have recently been developed based on a mixture of measurements and modelling to characterize the optics of such systems. This paper describes the workflow needed to create then use these BSDF datasets in the Radiance lighting simulation software. Limited comparisons are made between visualizations produced using the standard ray-tracing method, the BSDF method, and that taken in a full-scale outdoor mockup.

  20. Common modeling system for digital simulation

    NASA Technical Reports Server (NTRS)

    Painter, Rick

    1994-01-01

    The Joint Modeling and Simulation System is a tri-service investigation into a common modeling framework for the development digital models. The basis for the success of this framework is an X-window-based, open systems architecture, object-based/oriented methodology, standard interface approach to digital model construction, configuration, execution, and post processing. For years Department of Defense (DOD) agencies have produced various weapon systems/technologies and typically digital representations of the systems/technologies. These digital representations (models) have also been developed for other reasons such as studies and analysis, Cost Effectiveness Analysis (COEA) tradeoffs, etc. Unfortunately, there have been no Modeling and Simulation (M&S) standards, guidelines, or efforts towards commonality in DOD M&S. The typical scenario is an organization hires a contractor to build hardware and in doing so an digital model may be constructed. Until recently, this model was not even obtained by the organization. Even if it was procured, it was on a unique platform, in a unique language, with unique interfaces, and, with the result being UNIQUE maintenance required. Additionally, the constructors of the model expended more effort in writing the 'infrastructure' of the model/simulation (e.g. user interface, database/database management system, data journalizing/archiving, graphical presentations, environment characteristics, other components in the simulation, etc.) than in producing the model of the desired system. Other side effects include: duplication of efforts; varying assumptions; lack of credibility/validation; and decentralization in policy and execution. J-MASS provides the infrastructure, standards, toolset, and architecture to permit M&S developers and analysts to concentrate on the their area of interest.

  1. Runway Incursion Prevention System Simulation Evaluation

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.

    2002-01-01

    A Runway Incursion Prevention System (RIPS) was evaluated in a full mission simulation study at the NASA Langley Research center in March 2002. RIPS integrates airborne and ground-based technologies to provide (1) enhanced surface situational awareness to avoid blunders and (2) alerts of runway conflicts in order to prevent runway incidents while also improving operational capability. A series of test runs was conducted in a high fidelity simulator. The purpose of the study was to evaluate the RIPS airborne incursion detection algorithms and associated alerting and airport surface display concepts. Eight commercial airline crews participated as test subjects completing 467 test runs. This paper gives an overview of the RIPS, simulation study, and test results.

  2. Efficient multiscale simulation of simple metallic systems

    NASA Astrophysics Data System (ADS)

    Choly, Nicholas Isaac

    2004-12-01

    The steady increase in computational resources and numerical sophistication has brought about a new approach in physical simulation. The methods that comprise this approach are known as multiscale methods, and have the defining characteristic of combining several simulation methods together, rendering tractable physical problems that no single simulation method can resolve. We have developed an approach for coupling quantum-mechanical and classical methods for the efficient simulation of multiscale problems in simple metals. The present multiscale method employs orbital-free density functional theory, in which fictitious orbitals are never introduced. We review the theory, and describe the state-of-the-art functionals associated with it. We have developed an efficient simulation code for performing orbital-free density functional theory calculations, and we describe the methods developed to treat the functional minimization problem. One of the biggest barriers hindering the widespread use of orbital-free methods is that only local pseudopotentials can be used, and hence the powerful machinery of norm-conserving pseudopotentials is inapplicable. We develop a similar machinery for local pseudopotentials, and we report on the application of these methods. We solve several problems associated with the efficient use of orbital-free density functional methods. Certain orbital-free methods are formulated in reciprocal space and are applicable to periodic systems. Incorporation of these methods in a multiscale setting requires that the effects of periodicity be absent. A direct translation of the methods to real space is extremely inefficient. Motivated by these considerations, we have developed an efficient method for applying orbital-free methods to non-periodic systems. We also overcome an algorithmic problem with the calculation of ionic forces in grid-based electronic structure methods in general. We develop and test an efficient method for computing ionic forces that

  3. Holodeck: Telepresence Dome Visualization System Simulations

    NASA Technical Reports Server (NTRS)

    Hite, Nicolas

    2012-01-01

    This paper explores the simulation and consideration of different image-projection strategies for the Holodeck, a dome that will be used for highly immersive telepresence operations in future endeavors of the National Aeronautics and Space Administration (NASA). Its visualization system will include a full 360 degree projection onto the dome's interior walls in order to display video streams from both simulations and recorded video. Because humans innately trust their vision to precisely report their surroundings, the Holodeck's visualization system is crucial to its realism. This system will be rigged with an integrated hardware and software infrastructure-namely, a system of projectors that will relay with a Graphics Processing Unit (GPU) and computer to both project images onto the dome and correct warping in those projections in real-time. Using both Computer-Aided Design (CAD) and ray-tracing software, virtual models of various dome/projector geometries were created and simulated via tracking and analysis of virtual light sources, leading to the selection of two possible configurations for installation. Research into image warping and the generation of dome-ready video content was also conducted, including generation of fisheye images, distortion correction, and the generation of a reliable content-generation pipeline.

  4. HSI Prototypes for Human Systems Simulation Laboratory

    SciTech Connect

    Jokstad, Håkon; McDonald, Rob

    2015-09-01

    This report describes in detail the design and features of three Human System Interface (HSI) prototypes developed by the Institutt for Energiteknikk (IFE) in support of the U.S. Department of Energy’s Light Water Reactor Sustainability Program under Contract 128420 through Idaho National Laboratory (INL). The prototypes are implemented for the Generic Pressurized Water Reactor simulator and installed in the Human Systems Simulation Laboratory at INL. The three prototypes are: 1) Power Ramp display 2) RCS Heat-up and Cool-down display 3) Estimated time to limit display The power ramp display and the RCS heat-up/cool-down display are designed to provide good visual indications to the operators on how well they are performing their task compared to their target ramp/heat-up/cool-down rate. The estimated time to limit display is designed to help operators restore levels or pressures before automatic or required manual actions are activated.

  5. Data Systems Dynamic Simulation - A total system for data system design assessments and trade studies

    NASA Technical Reports Server (NTRS)

    Hooper, J. W.; Rowe, D. W.

    1978-01-01

    Data Systems Dynamic Simulation is a simulation system designed to reduce cost and time and increase the confidence and comprehensiveness of Data Systems Simulation. It is designed to simulate large data processing and communications systems from end-to-end or by subsystem. Those features relevant to system timing, control, sizing, personnel support activities, cost and external influences are modeled. Emphasis is placed on ease of use, comprehensive system performance measures, and extensive post simulation analysis capability. The system has been used to support trade studies of the NASA data system needs in the 1985 to 1990 time frame.

  6. A simple method for simulating gasdynamic systems

    NASA Technical Reports Server (NTRS)

    Hartley, Tom T.

    1991-01-01

    A simple method for performing digital simulation of gasdynamic systems is presented. The approach is somewhat intuitive, and requires some knowledge of the physics of the problem as well as an understanding of the finite difference theory. The method is explicitly shown in appendix A which is taken from the book by P.J. Roache, 'Computational Fluid Dynamics,' Hermosa Publishers, 1982. The resulting method is relatively fast while it sacrifices some accuracy.

  7. Optical simulations for Ambilight TV systems

    NASA Astrophysics Data System (ADS)

    Bruyneel, Filip; Lanoye, Lieve

    2012-06-01

    Ambilight is a unique Philips feature, where RGB LEDs are used to create a dynamic light halo around the television. This extends the screen and hence increases the viewing experience, as it draws the viewer more into the action on the screen. The feature receives very positive consumer feedback. However, implementing Ambilight in the increasingly stringent design boundary conditions of a slim and thin TV set is a challenging task. Optical simulations play a vital role in each step of the Ambilight development. Ranging from prototype to final product, we use simulations, next to prototyping, to aid the choice of LEDs, optical materials and optical systems during different phases of the design process. Each step the impact of the optical system on the mechanical design and TV set dimensions needs to be taken into account. Moreover, optical simulations are essential to guarantee the required optical performance given a big spread in LED performance, mechanical tolerances and material properties. Next to performance, optical efficiency is also an important parameter to evaluate an optical design, as it establishes the required number of LEDs and the total LED power. As such optical efficiency defines the thermal power which needs to be dissipated by the LED system. The innovation roadmap does not stop here. For future systems we see a miniaturization trend, where smaller LED packages and smaller dies are used. This evolution makes the impact of mechanical tolerances on the optical design more severe. Consequentially, this approach poses a whole new challenge to the way we use optical simulations in our design process.

  8. Simulation-based disassembly systems design

    NASA Astrophysics Data System (ADS)

    Ohlendorf, Martin; Herrmann, Christoph; Hesselbach, Juergen

    2004-02-01

    Recycling of Waste of Electrical and Electronic Equipment (WEEE) is a matter of actual concern, driven by economic, ecological and legislative reasons. Here, disassembly as the first step of the treatment process plays a key role. To achieve sustainable progress in WEEE disassembly, the key is not to limit analysis and planning to merely disassembly processes in a narrow sense, but to consider entire disassembly plants including additional aspects such as internal logistics, storage, sorting etc. as well. In this regard, the paper presents ways of designing, dimensioning, structuring and modeling different disassembly systems. Goal is to achieve efficient and economic disassembly systems that allow recycling processes complying with legal requirements. Moreover, advantages of applying simulation software tools that are widespread and successfully utilized in conventional industry sectors are addressed. They support systematic disassembly planning by means of simulation experiments including consecutive efficiency evaluation. Consequently, anticipatory recycling planning considering various scenarios is enabled and decisions about which types of disassembly systems evidence appropriateness for specific circumstances such as product spectrum, throughput, disassembly depth etc. is supported. Furthermore, integration of simulation based disassembly planning in a holistic concept with configuration of interfaces and data utilization including cost aspects is described.

  9. Digital system for structural dynamics simulation

    SciTech Connect

    Krauter, A.I.; Lagace, L.J.; Wojnar, M.K.; Glor, C.

    1982-11-01

    State-of-the-art digital hardware and software for the simulation of complex structural dynamic interactions, such as those which occur in rotating structures (engine systems). System were incorporated in a designed to use an array of processors in which the computation for each physical subelement or functional subsystem would be assigned to a single specific processor in the simulator. These node processors are microprogrammed bit-slice microcomputers which function autonomously and can communicate with each other and a central control minicomputer over parallel digital lines. Inter-processor nearest neighbor communications busses pass the constants which represent physical constraints and boundary conditions. The node processors are connected to the six nearest neighbor node processors to simulate the actual physical interface of real substructures. Computer generated finite element mesh and force models can be developed with the aid of the central control minicomputer. The control computer also oversees the animation of a graphics display system, disk-based mass storage along with the individual processing elements.

  10. Digital system for structural dynamics simulation

    NASA Technical Reports Server (NTRS)

    Krauter, A. I.; Lagace, L. J.; Wojnar, M. K.; Glor, C.

    1982-01-01

    State-of-the-art digital hardware and software for the simulation of complex structural dynamic interactions, such as those which occur in rotating structures (engine systems). System were incorporated in a designed to use an array of processors in which the computation for each physical subelement or functional subsystem would be assigned to a single specific processor in the simulator. These node processors are microprogrammed bit-slice microcomputers which function autonomously and can communicate with each other and a central control minicomputer over parallel digital lines. Inter-processor nearest neighbor communications busses pass the constants which represent physical constraints and boundary conditions. The node processors are connected to the six nearest neighbor node processors to simulate the actual physical interface of real substructures. Computer generated finite element mesh and force models can be developed with the aid of the central control minicomputer. The control computer also oversees the animation of a graphics display system, disk-based mass storage along with the individual processing elements.

  11. Numerical Propulsion System Simulation: An Overview

    NASA Technical Reports Server (NTRS)

    Lytle, John K.

    2000-01-01

    The cost of implementing new technology in aerospace propulsion systems is becoming prohibitively expensive and time consuming. One of the main contributors to the high cost and lengthy time is the need to perform many large-scale hardware tests and the inability to integrate all appropriate subsystems early in the design process. The NASA Glenn Research Center is developing the technologies required to enable simulations of full aerospace propulsion systems in sufficient detail to resolve critical design issues early in the design process before hardware is built. This concept, called the Numerical Propulsion System Simulation (NPSS), is focused on the integration of multiple disciplines such as aerodynamics, structures and heat transfer with computing and communication technologies to capture complex physical processes in a timely and cost-effective manner. The vision for NPSS, as illustrated, is to be a "numerical test cell" that enables full engine simulation overnight on cost-effective computing platforms. There are several key elements within NPSS that are required to achieve this capability: 1) clear data interfaces through the development and/or use of data exchange standards, 2) modular and flexible program construction through the use of object-oriented programming, 3) integrated multiple fidelity analysis (zooming) techniques that capture the appropriate physics at the appropriate fidelity for the engine systems, 4) multidisciplinary coupling techniques and finally 5) high performance parallel and distributed computing. The current state of development in these five area focuses on air breathing gas turbine engines and is reported in this paper. However, many of the technologies are generic and can be readily applied to rocket based systems and combined cycles currently being considered for low-cost access-to-space applications. Recent accomplishments include: (1) the development of an industry-standard engine cycle analysis program and plug 'n play

  12. GTOSS: Generalized Tethered Object Simulation System

    NASA Technical Reports Server (NTRS)

    Lang, David D.

    1987-01-01

    GTOSS represents a tether analysis complex which is described by addressing its family of modules. TOSS is a portable software subsystem specifically designed to be introduced into the environment of any existing vehicle dynamics simulation to add the capability of simulating multiple interacting objects (via multiple tethers). These objects may interact with each other as well as with the vehicle into whose environment TOSS is introduced. GTOSS is a stand alone tethered system analysis program, representing an example of TOSS having been married to a host simulation. RTOSS is the Results Data Base (RDB) subsystem designed to archive TOSS simulation results for future display processing. DTOSS is a display post processors designed to utilize the RDB. DTOSS extracts data from the RDB for multi-page printed time history displays. CTOSS is similar to DTOSS, but is designed to create ASCII plot files. The same time history data formats provided for DTOSS (for printing) are available via CTOSS for plotting. How these and other modules interact with each other is discussed.

  13. Mathematical simulation of Earth system dynamics

    NASA Astrophysics Data System (ADS)

    Dymnikov, V. P.; Lykosov, V. N.; Volodin, E. M.

    2015-05-01

    The mathematical simulation of the Earth system, the dynamics of which depends on physical, chemical, biological, and other processes and which requires interdisciplinary approaches to studying this problem, is considered. The term "the Earth system" extends the concept "the climatic system," since additional geospheres (lithosphere, heliosphere, etc.) are taken into account and a wider range of physical, chemical, biological, and social interactions is described. The present-day level of climate modeling is discussed, and some data obtained at the Institute of Numerical Mathematics, Russian Academy of Sciences (INM RAS), are presented for this purpose. The prospects for further development of climate models toward the creation of the Earth system models based on a seamless approach, according to which a unified model is used to make short-term (several days) and long-term (climatic) prediction, are considered.

  14. Communication Systems Simulation Laboratory (CSSL): Simulation Planning Guide

    NASA Technical Reports Server (NTRS)

    Schlesinger, Adam

    2012-01-01

    The simulation process, milestones and inputs are unknowns to first-time users of the CSSL. The Simulation Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their engineering personnel in simulation planning and execution. Material covered includes a roadmap of the simulation process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, facility interfaces, and inputs necessary to define scope, cost, and schedule are included as an appendix to the guide.

  15. Computational simulation of concurrent engineering for aerospace propulsion systems

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Singhal, S. N.

    1992-01-01

    Results are summarized of an investigation to assess the infrastructure available and the technology readiness in order to develop computational simulation methods/software for concurrent engineering. These results demonstrate that development of computational simulations methods for concurrent engineering is timely. Extensive infrastructure, in terms of multi-discipline simulation, component-specific simulation, system simulators, fabrication process simulation, and simulation of uncertainties - fundamental in developing such methods, is available. An approach is recommended which can be used to develop computational simulation methods for concurrent engineering for propulsion systems and systems in general. Benefits and facets needing early attention in the development are outlined.

  16. Computational simulation for concurrent engineering of aerospace propulsion systems

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Singhal, S. N.

    1993-01-01

    Results are summarized for an investigation to assess the infrastructure available and the technology readiness in order to develop computational simulation methods/software for concurrent engineering. These results demonstrate that development of computational simulation methods for concurrent engineering is timely. Extensive infrastructure, in terms of multi-discipline simulation, component-specific simulation, system simulators, fabrication process simulation, and simulation of uncertainties--fundamental to develop such methods, is available. An approach is recommended which can be used to develop computational simulation methods for concurrent engineering of propulsion systems and systems in general. Benefits and issues needing early attention in the development are outlined.

  17. Simulation of paraequilibrium growth in multicomponent systems

    NASA Astrophysics Data System (ADS)

    Ghosh, G.; Olson, G. B.

    2001-03-01

    A methodology to simulate paraequilibrium (PE) growth in multicomponent systems using the DIC-TRA (Diffusion-Controlled Transformation) software is presented. For any given multicomponent system containing substitutional and interstitial elements, the basic approach is to define a hypothetical element Z, whose thermodynamic and mobility parameters are expressed in terms of the weighted average (with respect to site fraction) of the thermodynamic parameters and mobilities of the substitutional alloying elements. This procedure facilitates the calculation of PE phase diagrams and the PE growth simulations directly in the Thermo-Calc and DICTRA software, respectively. The results of two distinct case studies in multicomponent alloys are presented. In the first example, we simulate the isothermal growth of PE cementite in an Fe-C-Co-Cr-Mo-Ni secondary hardening steel during tempering. This is of practical importance in modeling the carbide precipitation kinetics during secondary hardening. In the second example, we have presented the results of PE ferrite growth during continuous cooling from an intercritical temperature in an Fe-Al-C-Mn-Si low-alloy steel. This is of importance to the design of triple-phase steels containing an austenite that has optimum stability, to facilitate stress-induced transformation under dynamic loading. The results of both simulations are in good accord with experimental results. The model calculations do not consider any resistive or dissipative forces, such as the interfacial energy, strain energy, or solute drag, and, as a result, the interface velocities represent an upper limit under the available chemical driving force.

  18. Scene simulation for passive IR systems

    NASA Technical Reports Server (NTRS)

    Holt, J. D.; Dawbarn, R.; Bailey, A. B.

    1986-01-01

    The development of large mosaic detector arrays will allow for the construction of staring long wave infrared (LWIR) sensors which can observe large fields of view instantaneously and continuously. In order to evaluate and exercise these new systems, it will be necessary to provide simulated scenes of many moving targets against an infrared clutter background. Researchers are currently developing a projector/screen system. This system is comprised of a mechanical scanner, a diffuse screen, and a miniature blackbody. A prototype of the mechanical scanner, which is comprised of four independently driven scanners, has been designed, fabricated, and evaluated under room and cryogenic vacuum conditions. A large diffuse screen has been constructed and tested for structural integrity under cryogenic/vacuum thermal cycling. Construction techniques have been developed for the fabrication of miniature high-temperature blackbody sources. Finally, a concept has been developed to use this miniature blackbody to produce a spectrally tailorable source.

  19. VOCs monitoring system simulation and design

    NASA Astrophysics Data System (ADS)

    Caldararu, Florin; Vasile, Alexandru; Vatra, Cosmin

    2010-11-01

    The designed and simulated system will be used in the tanning industry, for Volatile Organic Compound (VOC) measurements. In this industry, about 90% of the solvent contained in the emulsions evaporates during its application, giving rise to VOC, which are at the same time hazardous atmospheric pollutants and one of the sources of ground level photochemical ozone formation. It results that a monitoring system is necessary in a leather finishing process, in order to detect hazardous VOC concentration and conducting process in order of VOC concentration diminishing. The paper presents the design of a VOC monitoring system, which includes sensors for VOCs and temperature, the conditioning circuitry for these sensors, the suction system of the gas in the hood, the data acquisition and the computing system and graphic interface. The used sensor in the detection system is a semiconductor sensor, produced by Figaro Engineering Inc., characterized by a short response time, high sensitivity at almost all VOC substances. The design of the conditioning circuitry and data acquisition is done in order to compensate the sensor response variation with temperature and to maintain the low response time of the sensor. The temperature compensation is obtained by using a thermistor circuitry, and the compensation is done within the software design. A Mitsubishi PLC is used to receive the output signals of the circuits including the sensor and of the thermistor, respectively. The acquisition and computing system is done using Mitsubishi ALPHA 2 controller and a graphical terminal, GOT 1000.

  20. End-to-End Radiographic Systems Simulation

    SciTech Connect

    Mathews, A.; Kwan, T.; Buescher, K.; Snell, C.; Adams, K.

    1999-07-23

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to develop a validated end-to-end radiographic model that could be applied to both x-rays and protons. The specific objectives were to link hydrodynamic, transport, and magneto-hydrodynamic simulation software for purposes of modeling radiographic systems. In addition, optimization and analysis algorithms were to be developed to validate physical models and optimize the design of radiographic facilities.

  1. Engineering simulations for cancer systems biology.

    PubMed

    Bown, James; Andrews, Paul S; Deeni, Yusuf; Goltsov, Alexey; Idowu, Michael; Polack, Fiona A C; Sampson, Adam T; Shovman, Mark; Stepney, Susan

    2012-11-01

    Computer simulation can be used to inform in vivo and in vitro experimentation, enabling rapid, low-cost hypothesis generation and directing experimental design in order to test those hypotheses. In this way, in silico models become a scientific instrument for investigation, and so should be developed to high standards, be carefully calibrated and their findings presented in such that they may be reproduced. Here, we outline a framework that supports developing simulations as scientific instruments, and we select cancer systems biology as an exemplar domain, with a particular focus on cellular signalling models. We consider the challenges of lack of data, incomplete knowledge and modelling in the context of a rapidly changing knowledge base. Our framework comprises a process to clearly separate scientific and engineering concerns in model and simulation development, and an argumentation approach to documenting models for rigorous way of recording assumptions and knowledge gaps. We propose interactive, dynamic visualisation tools to enable the biological community to interact with cellular signalling models directly for experimental design. There is a mismatch in scale between these cellular models and tissue structures that are affected by tumours, and bridging this gap requires substantial computational resource. We present concurrent programming as a technology to link scales without losing important details through model simplification. We discuss the value of combining this technology, interactive visualisation, argumentation and model separation to support development of multi-scale models that represent biologically plausible cells arranged in biologically plausible structures that model cell behaviour, interactions and response to therapeutic interventions. PMID:22974398

  2. Sensor Data Qualification Technique Applied to Gas Turbine Engines

    NASA Technical Reports Server (NTRS)

    Csank, Jeffrey T.; Simon, Donald L.

    2013-01-01

    This paper applies a previously developed sensor data qualification technique to a commercial aircraft engine simulation known as the Commercial Modular Aero-Propulsion System Simulation 40,000 (C-MAPSS40k). The sensor data qualification technique is designed to detect, isolate, and accommodate faulty sensor measurements. It features sensor networks, which group various sensors together and relies on an empirically derived analytical model to relate the sensor measurements. Relationships between all member sensors of the network are analyzed to detect and isolate any faulty sensor within the network.

  3. Development of the infrared target simulation system

    NASA Astrophysics Data System (ADS)

    Meng, Xiangkai; Tong, Shoufeng; Dong, Yan; Song, Yansong; Dong, Keyan

    2014-11-01

    In order to provide a set of field test equipment for the infrared system of modern weapon equipments and other optics instruments, a set of large-scale resistance-type infrared target system was designed. First, the large-scale infrared target was designed in modular construction. It was decomposed into several independent and controllable units. Then the working principle of the system was introduced. Three modes of thermal exchange (conduction, convection and radiation) and the computing methods for each mode were given under thermal equilibrium conditions through modeling and simulating. Periphery electro-circuit and control software were carried out as well. Finally, the performance of the system was tested. Meanwhile novel ways of temperature compensation to improve the uniformity of the surface temperature of the target was introduced. The experimental results show that the infrared target could meet test requirements for infrared imaging weaponry which wavelengths from 8 μm to 14 μm. The temperature control precision can reach 0.5ms. In conclusion, the infrared target system can satisfy requirements of reliability, high precision, as well as strong anti-jamming and stabilization.

  4. Epidemilogical Simulation System, Version 2.4

    SciTech Connect

    2004-01-30

    EpiSims uses a detailed simulation of disease spread to evaluate demographically and geographically targeted biological threat reduction strategies. Abstract: EpiSims simulates the spread of disease and analyzes the consequences of intervention strategies in a large urban area at the level of individuals. The simulation combines models of three dynamical systems: urban social networks, disease transmission, and within-host progression of a disease. Validated population mobility and activity generation technology provides the social network models, Disease models are based on fusion of expert opinion and available data. EpiSims provides a previously unavailable detailed representation of the course of an outbreak in urban area. A letter of August 16, 2002 from the Office of Homeland Security states: "Ability of EpiSims to provide comprehensive data on daily activity patterns of individuals makes it far superior to traditional SIR models — clearly had an impact on pre-attack smallpox vaccination policy." EpiSims leverages a unique Los Alamos National Laboratory resource — the population mobility and activity data developed by TRANSIMS (Transportation Analysis and SiMulation System) — to create epidemiological analyses at an unprecedented level of detail. We create models of microscopic (individual-level) physical and biological processes from which, through simulation, emerge the macroscopic (urban regional level) quantities that are the inputs to alternative models. For example, the contact patterns of individuals in different demographic groups determine the overall mixing rates those groups. The characteristics of a person-to-person transmission together with their contact patterns determine the reproductive numbers — how many people will be infected on average by each case. Mixing rates and reproductive numbers are the basic parameters of other epidemiological models. Because interventions — and people’s reactions to them — are ultimately applied at the

  5. Epidemilogical Simulation System, Version 2.4

    2004-01-30

    EpiSims uses a detailed simulation of disease spread to evaluate demographically and geographically targeted biological threat reduction strategies. Abstract: EpiSims simulates the spread of disease and analyzes the consequences of intervention strategies in a large urban area at the level of individuals. The simulation combines models of three dynamical systems: urban social networks, disease transmission, and within-host progression of a disease. Validated population mobility and activity generation technology provides the social network models, Disease modelsmore » are based on fusion of expert opinion and available data. EpiSims provides a previously unavailable detailed representation of the course of an outbreak in urban area. A letter of August 16, 2002 from the Office of Homeland Security states: "Ability of EpiSims to provide comprehensive data on daily activity patterns of individuals makes it far superior to traditional SIR models — clearly had an impact on pre-attack smallpox vaccination policy." EpiSims leverages a unique Los Alamos National Laboratory resource — the population mobility and activity data developed by TRANSIMS (Transportation Analysis and SiMulation System) — to create epidemiological analyses at an unprecedented level of detail. We create models of microscopic (individual-level) physical and biological processes from which, through simulation, emerge the macroscopic (urban regional level) quantities that are the inputs to alternative models. For example, the contact patterns of individuals in different demographic groups determine the overall mixing rates those groups. The characteristics of a person-to-person transmission together with their contact patterns determine the reproductive numbers — how many people will be infected on average by each case. Mixing rates and reproductive numbers are the basic parameters of other epidemiological models. Because interventions — and people’s reactions to them — are ultimately applied

  6. 21 CFR 892.5840 - Radiation therapy simulation system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiation therapy simulation system. 892.5840... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5840 Radiation therapy simulation system. (a) Identification. A radiation therapy simulation system is a fluoroscopic or radiographic...

  7. 21 CFR 892.5840 - Radiation therapy simulation system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiation therapy simulation system. 892.5840... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5840 Radiation therapy simulation system. (a) Identification. A radiation therapy simulation system is a fluoroscopic or radiographic...

  8. 21 CFR 892.5840 - Radiation therapy simulation system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiation therapy simulation system. 892.5840... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5840 Radiation therapy simulation system. (a) Identification. A radiation therapy simulation system is a fluoroscopic or radiographic...

  9. 21 CFR 892.5840 - Radiation therapy simulation system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiation therapy simulation system. 892.5840... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5840 Radiation therapy simulation system. (a) Identification. A radiation therapy simulation system is a fluoroscopic or radiographic...

  10. 21 CFR 892.5840 - Radiation therapy simulation system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiation therapy simulation system. 892.5840... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5840 Radiation therapy simulation system. (a) Identification. A radiation therapy simulation system is a fluoroscopic or radiographic...

  11. Simulation Model of Mobile Detection Systems

    SciTech Connect

    Edmunds, T; Faissol, D; Yao, Y

    2009-01-27

    In this paper, we consider a mobile source that we attempt to detect with man-portable, vehicle-mounted or boat-mounted radiation detectors. The source is assumed to transit an area populated with these mobile detectors, and the objective is to detect the source before it reaches a perimeter. We describe a simulation model developed to estimate the probability that one of the mobile detectors will come in to close proximity of the moving source and detect it. We illustrate with a maritime simulation example. Our simulation takes place in a 10 km by 5 km rectangular bay patrolled by boats equipped with 2-inch x 4-inch x 16-inch NaI detectors. Boats to be inspected enter the bay and randomly proceed to one of seven harbors on the shore. A source-bearing boat enters the mouth of the bay and proceeds to a pier on the opposite side. We wish to determine the probability that the source is detected and its range from target when detected. Patrol boats select the nearest in-bound boat for inspection and initiate an intercept course. Once within an operational range for the detection system, a detection algorithm is started. If the patrol boat confirms the source is not present, it selects the next nearest boat for inspection. Each run of the simulation ends either when a patrol successfully detects a source or when the source reaches its target. Several statistical detection algorithms have been implemented in the simulation model. First, a simple k-sigma algorithm, which alarms with the counts in a time window exceeds the mean background plus k times the standard deviation of background, is available to the user. The time window used is optimized with respect to the signal-to-background ratio for that range and relative speed. Second, a sequential probability ratio test [Wald 1947] is available, and configured in this simulation with a target false positive probability of 0.001 and false negative probability of 0.1. This test is utilized when the mobile detector maintains

  12. Application of control theory to dynamic systems simulation

    NASA Technical Reports Server (NTRS)

    Auslander, D. M.; Spear, R. C.; Young, G. E.

    1982-01-01

    The application of control theory is applied to dynamic systems simulation. Theory and methodology applicable to controlled ecological life support systems are considered. Spatial effects on system stability, design of control systems with uncertain parameters, and an interactive computing language (PARASOL-II) designed for dynamic system simulation, report quality graphics, data acquisition, and simple real time control are discussed.

  13. An HLA based design of space system simulation environment

    NASA Astrophysics Data System (ADS)

    Li, Yinghua; Li, Yong; Liu, Jie

    2007-06-01

    Space system simulation is involved in many application fields, such as space remote sensing and space communication, etc. A simulation environment which can be shared by different space system simulation is needed. Two rules, called object template towing and hierarchical reusability, are proposed. Based on these two rules, the architecture, the network structure and the function structure of the simulation environment are designed. Then, the mechanism of utilizing data resources, inheriting object models and running simulation systems are also constructed. These mechanisms make the simulation objects defined in advance be easily inherited by different HLA federates, the fundamental simulation models be shared by different simulation systems. Therefore, the simulation environment is highly universal and reusable.

  14. Cardiovascular system simulation in biomedical engineering education.

    NASA Technical Reports Server (NTRS)

    Rideout, V. C.

    1972-01-01

    Use of complex cardiovascular system models, in conjunction with a large hybrid computer, in biomedical engineering courses. A cardiovascular blood pressure-flow model, driving a compartment model for the study of dye transport, was set up on the computer for use as a laboratory exercise by students who did not have the computer experience or skill to be able to easily set up such a simulation involving some 27 differential equations running at 'real time' rate. The students were given detailed instructions regarding the model, and were then able to study effects such as those due to septal and valve defects upon the pressure, flow, and dye dilution curves. The success of this experiment in the use of involved models in engineering courses was such that it seems that this type of laboratory exercise might be considered for use in physiology courses as an adjunct to animal experiments.

  15. Designing a SCADA system simulator for fast breeder reactor

    NASA Astrophysics Data System (ADS)

    Nugraha, E.; Abdullah, A. G.; Hakim, D. L.

    2016-04-01

    SCADA (Supervisory Control and Data Acquisition) system simulator is a Human Machine Interface-based software that is able to visualize the process of a plant. This study describes the results of the process of designing a SCADA system simulator that aims to facilitate the operator in monitoring, controlling, handling the alarm, accessing historical data and historical trend in Nuclear Power Plant (NPP) type Fast Breeder Reactor (FBR). This research used simulation to simulate NPP type FBR Kalpakkam in India. This simulator was developed using Wonderware Intouch software 10 and is equipped with main menu, plant overview, area graphics, control display, set point display, alarm system, real-time trending, historical trending and security system. This simulator can properly simulate the principle of energy flow and energy conversion process on NPP type FBR. This SCADA system simulator can be used as training media for NPP type FBR prospective operators.

  16. History of visual systems in the Systems Engineering Simulator

    NASA Technical Reports Server (NTRS)

    Christianson, David C.

    1989-01-01

    The Systems Engineering Simulator (SES) houses a variety of real-time computer generated visual systems. The earliest machine dates from the mid-1960's and is one of the first real-time graphics systems in the world. The latest acquisition is the state-of-the-art Evans and Sutherland CT6. Between the span of time from the mid-1960's to the late 1980's, tremendous strides have been made in the real-time graphics world. These strides include advances in both software and hardware engineering. The purpose is to explore the history of the development of these real-time computer generated image systems from the first machine to the present. Hardware advances as well as software algorithm changes are presented. This history is not only quite interesting but also provides us with a perspective with which we can look backward and forward.

  17. Computer simulator for a mobile telephone system

    NASA Technical Reports Server (NTRS)

    Schilling, D. L.; Ziegler, C.

    1983-01-01

    A software simulator to help NASA in the design of the LMSS was developed. The simulator will be used to study the characteristics of implementation requirements of the LMSS's configuration with specifications as outlined by NASA.

  18. Simulations of percutaneous RF ablation systems

    NASA Astrophysics Data System (ADS)

    Ryan, Thomas P.; Kwok, Jonathan; Beetel, Robert J.

    2003-06-01

    Breast and liver cancers provide an ongoing challenge in regard to treatment efficacy and successful clinical outcomes. A variety of percutaneous technology has been applied for thermal treatment of the liver and breast, including laser, microwave, cryogenic and radiofrequency (RF) devices. When simplicity and cost are factored in, RF hardware and applicators offer the most cost-effective treatment pathway by interventional radiologists and surgeons. To model percutaneous RF treatments in liver and breast, simulations were done in 3D with a finite element model. Three RF systems were modeled, including 1) single needle; 2) clustered needle, cooled and uncooled; and 3) deployable, hook electrodes. The results show the limitations of the systems in percutaneous procedures, depending on temperature limits, duration of treatment, and whether the devices are cooled or uncooled. For thermal treatment, the isotherm of 55°C was considered the margin of coagulation necrosis. The 3-D volumes of 55°C and 65°C isotherm shells aid in the selection of the best method to improve clinical outcomes, while paying attention to the size and shape of the applicator and duration of treatment.

  19. 2003 NASA Seal/Secondary Air System Workshop. Volume 1

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Editor); Hendricks, Robert C. (Editor)

    2004-01-01

    The following reports were included in the 2003 NASA Seal/Secondary Air System Workshop:Low Emissions Alternative Power (LEAP); Overview of NASA Glenn Seal Developments; NASA Ultra Efficient Engine Technology Project Overview; Development of Higher Temperature Abradable Seals for Industrial Gas Turbines; High Misalignment Carbon Seals for the Fan Drive Gear System Technologies; Compliant Foil Seal Investigations; Test Rig for Evaluating Active Turbine Blade Tip Clearance Control Concepts; Controls Considerations for Turbine Active Clearance Control; Non-Contacting Finger Seal Developments and Design Considerations; Effect of Flow-Induced Radial Load on Brush Seal/Rotor Contact Mechanics; Seal Developments at Flowserve Corporation; Investigations of High Pressure Acoustic Waves in Resonators With Seal-Like Features; Numerical Investigations of High Pressure Acoustic Waves in Resonators; Feltmetal Seal Material Through-Flow; "Bimodal" Nuclear Thermal Rocket (BNTR) Propulsion for Future Human Mars Exploration Missions; High Temperature Propulsion System Structural Seals for Future Space Launch Vehicles; Advanced Control Surface Seal Development for Future Space Vehicles; High Temperature Metallic Seal Development for Aero Propulsion and Gas Turbine Applications; and BrazeFoil Honeycomb.

  20. Data simulation for the Associated Particle Imaging system

    SciTech Connect

    Tunnell, L.N.

    1994-06-01

    A data simulation procedure for the Associated Particle Imaging (API) system has been developed by postprocessing output from the Monte Carlo Neutron Photon (MCNP) code. This paper compares the simulated results to our experimental data.

  1. A Unique Software System For Simulation-to-Flight Research

    NASA Technical Reports Server (NTRS)

    Chung, Victoria I.; Hutchinson, Brian K.

    2001-01-01

    "Simulation-to-Flight" is a research development concept to reduce costs and increase testing efficiency of future major aeronautical research efforts at NASA. The simulation-to-flight concept is achieved by using common software and hardware, procedures, and processes for both piloted-simulation and flight testing. This concept was applied to the design and development of two full-size transport simulators, a research system installed on a NASA B-757 airplane, and two supporting laboratories. This paper describes the software system that supports the simulation-to-flight facilities. Examples of various simulation-to-flight experimental applications were also provided.

  2. System simulation of a 0.2THz imaging radar

    NASA Astrophysics Data System (ADS)

    Zhu, Li; Deng, Chao; Zhang, Cun-lin; Zhao, Yue-jin

    2009-07-01

    Unlike traditional THz imaging system, we first report a design of 0.2THz stepped frequency radar system, and prove its feasibility by simulation. The stepped frequency radar working from 200GHz to 210GHz can provide centimeter accuracy. To demonstrate the feasibility of our design, we simulate our system by using Advanced Design System (ADS) and Simulink in Matlab. The transmitter line is simulated in ADS, while system-level simulation is carried out in Matlab. The simulation of transmitter is implemented by using parameters from actual products, which can ensure the reality of simulation. In this paper, we will present the methods and results of our simulation. From the results, we can conclude that our design is feasible.

  3. Evaluating the GPSS simulation model for the Viking batch computer system. [General Purpose Simulation System

    NASA Technical Reports Server (NTRS)

    Lee, J.-J.

    1976-01-01

    In anticipation of extremely heavy loading requirements by the Viking mission during the post-landing periods, a GPSS model has been developed for the purpose of simulating these requirements on the Viking batch computer system. This paper presents the effort pursued in evaluating such a model and results thereby obtained. The evaluation effort consists of selecting the evaluation approach, collecting actual test run data, making comparisons and deriving conclusions.

  4. Simulation of P systems with active membranes on CUDA.

    PubMed

    Cecilia, José M; García, José M; Guerrero, Ginés D; Martínez-del-Amor, Miguel A; Pérez-Hurtado, Ignacio; Pérez-Jiménez, Mario J

    2010-05-01

    P systems or Membrane Systems provide a high-level computational modelling framework that combines the structure and dynamic aspects of biological systems in a relevant and understandable way. They are inherently parallel and non-deterministic computing devices. In this article, we discuss the motivation, design principles and key of the implementation of a simulator for the class of recognizer P systems with active membranes running on a (GPU). We compare our parallel simulator for GPUs to the simulator developed for a single central processing unit (CPU), showing that GPUs are better suited than CPUs to simulate P systems due to their highly parallel nature.

  5. System Synthesis in Preliminary Aircraft Design using Statistical Methods

    NASA Technical Reports Server (NTRS)

    DeLaurentis, Daniel; Mavris, Dimitri N.; Schrage, Daniel P.

    1996-01-01

    This paper documents an approach to conceptual and preliminary aircraft design in which system synthesis is achieved using statistical methods, specifically design of experiments (DOE) and response surface methodology (RSM). These methods are employed in order to more efficiently search the design space for optimum configurations. In particular, a methodology incorporating three uses of these techniques is presented. First, response surface equations are formed which represent aerodynamic analyses, in the form of regression polynomials, which are more sophisticated than generally available in early design stages. Next, a regression equation for an overall evaluation criterion is constructed for the purpose of constrained optimization at the system level. This optimization, though achieved in a innovative way, is still traditional in that it is a point design solution. The methodology put forward here remedies this by introducing uncertainty into the problem, resulting a solutions which are probabilistic in nature. DOE/RSM is used for the third time in this setting. The process is demonstrated through a detailed aero-propulsion optimization of a high speed civil transport. Fundamental goals of the methodology, then, are to introduce higher fidelity disciplinary analyses to the conceptual aircraft synthesis and provide a roadmap for transitioning from point solutions to probabalistic designs (and eventually robust ones).

  6. System Synthesis in Preliminary Aircraft Design Using Statistical Methods

    NASA Technical Reports Server (NTRS)

    DeLaurentis, Daniel; Mavris, Dimitri N.; Schrage, Daniel P.

    1996-01-01

    This paper documents an approach to conceptual and early preliminary aircraft design in which system synthesis is achieved using statistical methods, specifically Design of Experiments (DOE) and Response Surface Methodology (RSM). These methods are employed in order to more efficiently search the design space for optimum configurations. In particular, a methodology incorporating three uses of these techniques is presented. First, response surface equations are formed which represent aerodynamic analyses, in the form of regression polynomials, which are more sophisticated than generally available in early design stages. Next, a regression equation for an Overall Evaluation Criterion is constructed for the purpose of constrained optimization at the system level. This optimization, though achieved in an innovative way, is still traditional in that it is a point design solution. The methodology put forward here remedies this by introducing uncertainty into the problem, resulting in solutions which are probabilistic in nature. DOE/RSM is used for the third time in this setting. The process is demonstrated through a detailed aero-propulsion optimization of a High Speed Civil Transport. Fundamental goals of the methodology, then, are to introduce higher fidelity disciplinary analyses to the conceptual aircraft synthesis and provide a roadmap for transitioning from point solutions to probabilistic designs (and eventually robust ones).

  7. Future Directions in Biological Systems Simulation - A Role for ICASA?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The International Consortium for Agricultural Systems Applications (ICASA) advances systems research in agriculture and natural resource management by promoting the development and application of systems analysis tools and methodologies. This goal emphasizes, but is not limited to, simulation models...

  8. Explosive simulants for testing explosive detection systems

    DOEpatents

    Kury, John W.; Anderson, Brian L.

    1999-09-28

    Explosives simulants that include non-explosive components are disclosed that facilitate testing of equipment designed to remotely detect explosives. The simulants are non-explosive, non-hazardous materials that can be safely handled without any significant precautions. The simulants imitate real explosives in terms of mass density, effective atomic number, x-ray transmission properties, and physical form, including moldable plastics and emulsions/gels.

  9. Workflow simulation and its system development

    NASA Astrophysics Data System (ADS)

    Li, Renwang; Zhu, Zefei; Wang, Xianmei; Liu, Lei; Jiang, Xuefeng

    2005-12-01

    Workflow technique is a research hotspot in the field of advanced manufacturing technology. However, up to now workflow simulation still lacks necessary evaluation of rationality and validity. Therefore, a principle of workflow simulation was set forth; a kind of workflow simulation mechanism is proposed. It is divided into presentation layer, business logic layer and database layer. Then, taking process of handling business orders as example, and taking time, quality, cost and service as key factors, a feasible method was developed. Its simulation results of 30 days were listed and analyzed. At last, an amended process of handling business orders is brought forward.

  10. Extensions to Dynamic System Simulation of Fissile Solution Systems

    SciTech Connect

    Klein, Steven Karl; Bernardin, John David; Kimpland, Robert Herbert; Spernjak, Dusan

    2015-08-24

    Previous reports have documented the results of applying dynamic system simulation (DSS) techniques to model a variety of fissile solution systems. The SUPO (Super Power) aqueous homogeneous reactor (AHR) was chosen as the benchmark for comparison of model results to experimental data for steadystate operation.1 Subsequently, DSS was applied to additional AHR to verify results obtained for SUPO and extend modeling to prompt critical excursions, ramp reactivity insertions of various magnitudes and rate, and boiling operations in SILENE and KEWB (Kinetic Experiment Water Boiler).2 Additional models for pressurized cores (HRE: Homogeneous Reactor Experiment), annular core geometries, and accelerator-driven subcritical systems (ADAHR) were developed and results reported.3 The focus of each of these models is core dynamics; neutron kinetics, thermal hydraulics, radiolytic gas generation and transport are coupled to examine the time-based evolution of these systems from start-up through transition to steady-state. A common characteristic of these models is the assumption that (a) core cooling system inlet temperature and flow and (b) plenum gas inlet pressure and flow are held constant; no external (to core) component operations that may result in dynamic change to these parameters are considered. This report discusses extension of models to include explicit reference to cooling structures and radiolytic gas handling. The accelerator-driven subcritical generic system model described in References 3 and 4 is used as a basis for this extension.

  11. SuperB Simulation Production System

    NASA Astrophysics Data System (ADS)

    Tomassetti, L.; Bianchi, F.; Ciaschini, V.; Corvo, M.; Del Prete, D.; Di Simone, A.; Donvito, G.; Fella, A.; Franchini, P.; Giacomini, F.; Gianoli, A.; Longo, S.; Luitz, S.; Luppi, E.; Manzali, M.; Pardi, S.; Paolini, A.; Perez, A.; Rama, M.; Russo, G.; Santeramo, B.; Stroili, R.

    2012-12-01

    The SuperB asymmetric e+e- collider and detector to be built at the newly founded Nicola Cabibbo Lab will provide a uniquely sensitive probe of New Physics in the flavor sector of the Standard Model. Studying minute effects in the heavy quark and heavy lepton sectors requires a data sample of 75 ab-1 and a peak luminosity of 1036 cm-2 s-1. The SuperB Computing group is working on developing a simulation production framework capable to satisfy the experiment needs. It provides access to distributed resources in order to support both the detector design definition and its performance evaluation studies. During last year the framework has evolved from the point of view of job workflow, Grid services interfaces and technologies adoption. A complete code refactoring and sub-component language porting now permits the framework to sustain distributed production involving resources from two continents and Grid Flavors. In this paper we will report a complete description of the production system status of the art, its evolution and its integration with Grid services; in particular, we will focus on the utilization of new Grid component features as in LB and WMS version 3. Results from the last official SuperB production cycle will be reported.

  12. System dynamic simulation of precision segmented reflector

    NASA Technical Reports Server (NTRS)

    Shih, Choon-Foo; Lou, Michael C.

    1991-01-01

    A joint effort was undertaken on a Precision Segmented Reflector (PSR) Project. The missions in which the PSR is to be used will use large (up to 20 m in diameter) telescopes. The essential requirement for the telescopes is that the reflector surface of the primary mirror must be made extremely precise to allow no more than a few microns of errors and, additionally, this high surface precision must be maintained when the telescope is subjected to on-orbital mechanical and thermal disturbances. Based on the mass, size, and stability considerations, reflector surface formed by segmented, probably actively or passively controlled, composite panels are regarded as most suitable for future space based astronomical telescope applications. In addition to the design and fabrication of composite panels with a surface error of less than 3 microns RMS, PSR also develops related reflector structures, materials, control, and sensing technologies. As part of the planning effort for PSR Technology Demonstration, a system model which couples the reflector, consisting of panels, support truss and actuators, and the optical bench was assembled for dynamic simulations. Random vibration analyses using seismic data obtained from actual measurements at the test site designated for PSR Technology Demonstration are described.

  13. NASA Earth Observing System Simulator Suite (NEOS3): A Forward Simulation Framework for Observing System Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Niamsuwan, N.; Tanelli, S.; Johnson, M. P.; Jacob, J. C.; Jaruwatanadilok, S.; Oveisgharan, S.; Dao, D.; Simard, M.; Turk, F. J.; Tsang, L.; Liao, T. H.; Chau, Q.

    2014-12-01

    Future Earth observation missions will produce a large volume of interrelated data sets that will help us to cross-calibrate and validate spaceborne sensor measurements. A forward simulator is a crucial tool for examining the quality of individual products as well as resolving discrepancy among related data sets. NASA Earth Observing System Simulator Suite (NEOS3) is a highly customizable forward simulation tool for Earth remote sensing instruments. Its three-stage simulation process converts the 3D geophysical description of the scene being observed to corresponding electromagnetic emission and scattering signatures, and finally to observable parameters as reported by a (passive or active) remote sensing instrument. User-configurable options include selection of models for describing geophysical properties of atmospheric particles and their effects on the signal of interest, selection of wave scattering and propagation models, and activation of simplifying assumptions (trading between computation time and solution accuracy). The next generation of NEOS3, to be released in 2015, will feature additional state-of-the-art electromagnetic scattering models for various types of the Earth's surfaces and ground covers (e.g. layered snowpack, forest, vegetated soil, and sea ice) tailored specifically for missions like GPM and SMAP. To be included in 2015 is dedicated functionalities and interface that facilitate integrating NEOS3 into Observing System Simulation Experiment (OSSE) environments. This new generation of NEOS3 can also utilize high performance computing resources (parallel processing and cloud computing) and can be scaled to handle large or computation intensive problems. This presentation will highlight some notable features of NEOS3. Demonstration of its applications for evaluating new mission concepts, especially in the context of OSSE frameworks will also be presented.

  14. Distributed adaptive simulation through standards-based integration of simulators and adaptive learning systems.

    PubMed

    Bergeron, Bryan; Cline, Andrew; Shipley, Jaime

    2012-01-01

    We have developed a distributed, standards-based architecture that enables simulation and simulator designers to leverage adaptive learning systems. Our approach, which incorporates an electronic competency record, open source LMS, and open source microcontroller hardware, is a low-cost, pragmatic option to integrating simulators with traditional courseware. PMID:22356955

  15. A Runtime Verification Framework for Control System Simulation

    SciTech Connect

    Ciraci, Selim; Fuller, Jason C.; Daily, Jeffrey A.; Makhmalbaf, Atefe; Callahan, Charles D.

    2014-08-02

    n a standard workflow for the validation of a control system, the control system is implemented as an extension to a simulator. Such simulators are complex software systems, and engineers may unknowingly violate constraints a simulator places on extensions. As such, errors may be introduced in the implementation of either the control system or the simulator leading to invalid simulation results. This paper presents a novel runtime verification approach for verifying control system implementations within simulators. The major contribution of the approach is the two-tier specification process. In the first tier, engineers model constraints using a domain-specific language tailored to modeling a controller’s response to changes in its input. The language is high-level and effectively hides the implementation details of the simulator, allowing engineers to specify design-level constraints independent of low-level simulator interfaces. In the second tier, simulator developers provide mapping rules for mapping design-level constraints to the implementation of the simulator. Using the rules, an automated tool transforms the design-level specifications into simulator-specific runtime verification specifications and generates monitoring code which is injected into the implementation of the simulator. During simulation, these monitors observe the input and output variables of the control system and report changes to the verifier. The verifier checks whether these changes follow the constraints of the control system. We describe application of this approach to the verification of the constraints of an HVAC control system implemented with the power grid simulator GridLAB-D.

  16. A View on Future Building System Modeling and Simulation

    SciTech Connect

    Wetter, Michael

    2011-04-01

    This chapter presents what a future environment for building system modeling and simulation may look like. As buildings continue to require increased performance and better comfort, their energy and control systems are becoming more integrated and complex. We therefore focus in this chapter on the modeling, simulation and analysis of building energy and control systems. Such systems can be classified as heterogeneous systems because they involve multiple domains, such as thermodynamics, fluid dynamics, heat and mass transfer, electrical systems, control systems and communication systems. Also, they typically involve multiple temporal and spatial scales, and their evolution can be described by coupled differential equations, discrete equations and events. Modeling and simulating such systems requires a higher level of abstraction and modularisation to manage the increased complexity compared to what is used in today's building simulation programs. Therefore, the trend towards more integrated building systems is likely to be a driving force for changing the status quo of today's building simulation programs. Thischapter discusses evolving modeling requirements and outlines a path toward a future environment for modeling and simulation of heterogeneous building systems.A range of topics that would require many additional pages of discussion has been omitted. Examples include computational fluid dynamics for air and particle flow in and around buildings, people movement, daylight simulation, uncertainty propagation and optimisation methods for building design and controls. For different discussions and perspectives on the future of building modeling and simulation, we refer to Sahlin (2000), Augenbroe (2001) and Malkawi and Augenbroe (2004).

  17. A Process for Comparing Dynamics of Distributed Space Systems Simulations

    NASA Technical Reports Server (NTRS)

    Cures, Edwin Z.; Jackson, Albert A.; Morris, Jeffery C.

    2009-01-01

    The paper describes a process that was developed for comparing the primary orbital dynamics behavior between space systems distributed simulations. This process is used to characterize and understand the fundamental fidelities and compatibilities of the modeling of orbital dynamics between spacecraft simulations. This is required for high-latency distributed simulations such as NASA s Integrated Mission Simulation and must be understood when reporting results from simulation executions. This paper presents 10 principal comparison tests along with their rationale and examples of the results. The Integrated Mission Simulation (IMSim) (formerly know as the Distributed Space Exploration Simulation (DSES)) is a NASA research and development project focusing on the technologies and processes that are related to the collaborative simulation of complex space systems involved in the exploration of our solar system. Currently, the NASA centers that are actively participating in the IMSim project are the Ames Research Center, the Jet Propulsion Laboratory (JPL), the Johnson Space Center (JSC), the Kennedy Space Center, the Langley Research Center and the Marshall Space Flight Center. In concept, each center participating in IMSim has its own set of simulation models and environment(s). These simulation tools are used to build the various simulation products that are used for scientific investigation, engineering analysis, system design, training, planning, operations and more. Working individually, these production simulations provide important data to various NASA projects.

  18. Human Factors in the Simulation of Information Systems.

    ERIC Educational Resources Information Center

    Warren, James R.; And Others

    1997-01-01

    Discusses how simulation technology for the analysis of information systems (IS) supports human decision making. Examines online help and knowledge-based support, graphics, and visual interactive simulation (VIS) and animation. Concludes that there are opportunities to improve the decision support role of simulation technology in IS with enhanced…

  19. Plasma Heating Simulation in the VASIMR System

    NASA Technical Reports Server (NTRS)

    Ilin, Andrew V.; ChangDiaz, Franklin R.; Squire, Jared P.; Carter, Mark D.

    2005-01-01

    The paper describes the recent development in the simulation of the ion-cyclotron acceleration of the plasma in the VASIMR experiment. The modeling is done using an improved EMIR code for RF field calculation together with particle trajectory code for plasma transport calculat ion. The simulation results correlate with experimental data on the p lasma loading and predict higher ICRH performance for a higher density plasma target. These simulations assist in optimizing the ICRF anten na so as to achieve higher VASIMR efficiency.

  20. Simulation of water flow in terrestrial systems

    2008-12-18

    ParFlow is a parallel, variabley saturated groundwater flow code that is especially suitable for large scale problem. ParFlow simulates the three-dimensional saturated and variably saturated subsurface flow in heterogeneous porous media in three spatial dimensions. ParFlow's developemt and appkication has been on-ging for more than 10 uear. ParFlow has recently been extended to coupled surface-subsurface flow to enabel the simulation of hillslope runoff and channel routing in a truly integrated fashion. ParFlow simulates the three-dimensionalmore » varably saturated subsurface flow in strongly heterogeneous porous media in three spatial dimension.« less

  1. A computer simulator for development of engineering system design methodologies

    NASA Technical Reports Server (NTRS)

    Padula, S. L.; Sobieszczanski-Sobieski, J.

    1987-01-01

    A computer program designed to simulate and improve engineering system design methodology is described. The simulator mimics the qualitative behavior and data couplings occurring among the subsystems of a complex engineering system. It eliminates the engineering analyses in the subsystems by replacing them with judiciously chosen analytical functions. With the cost of analysis eliminated, the simulator is used for experimentation with a large variety of candidate algorithms for multilevel design optimization to choose the best ones for the actual application. Thus, the simulator serves as a development tool for multilevel design optimization strategy. The simulator concept, implementation, and status are described and illustrated with examples.

  2. Co-simulation of innovative integrated HVAC systems in buildings

    SciTech Connect

    Trcka, Marija; Hensena, Jan L.M.; Wetter, Michael

    2010-06-21

    Integrated performance simulation of buildings HVAC systems can help in reducing energy consumption and increasing occupant comfort. However, no single building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to analyze integrated building systems and to enable rapid prototyping of innovative building and system technologies. One way to alleviate this problem is to use co-simulation, as an integrated approach to simulation. This article elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in the here described co-simulation prototype. The prototype is validated with the results obtained from the traditional simulation approach. It is further used in a proof-of-concept case study to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling time step.

  3. Computer simulation of a few common process control systems

    SciTech Connect

    Muncy, M.P.

    1986-06-01

    This paper shows how to simulate five common process control systems on an IBM PC with a commercially available software package named TUTSIM. All steps involved in producing and checking each simulation are described as clearly as possible. Complete computer listings and output line plots are included to fully document each simulation. Sufficient information is provided so that readers of this paper can duplicate each simulation if they desire to do so. 10 refs., 13 figs., 11 tbls.

  4. Design, construction and evaluation of a simulated geothermal flow system

    SciTech Connect

    Mackanic, J.C.

    1980-07-28

    A system was designed and built to simulate the flow from a geothermal well. The simulated flow will be used to power a Lysholm engine, the performance of which will then be evaluated for different simulated geothermal flows. Two main subjects are covered: 1) the design, construction and evaluation of the behavior of the system that simulates the geothermal flow; included in that topic is a discussion of the probable behavior of the Lysholm engine when it is put into operation, and 2) the investigation of the use of dynamic modeling techniques to determine whether they can provide a suitable means for predicting the behavior of the system.

  5. Modeling and Simulation Tools: From Systems Biology to Systems Medicine.

    PubMed

    Olivier, Brett G; Swat, Maciej J; Moné, Martijn J

    2016-01-01

    Modeling is an integral component of modern biology. In this chapter we look into the role of the model, as it pertains to Systems Medicine, and the software that is required to instantiate and run it. We do this by comparing the development, implementation, and characteristics of tools that have been developed to work with two divergent methodologies: Systems Biology and Pharmacometrics. From the Systems Biology perspective we consider the concept of "Software as a Medical Device" and what this may imply for the migration of research-oriented, simulation software into the domain of human health.In our second perspective, we see how in practice hundreds of computational tools already accompany drug discovery and development at every stage of the process. Standardized exchange formats are required to streamline the model exchange between tools, which would minimize translation errors and reduce the required time. With the emergence, almost 15 years ago, of the SBML standard, a large part of the domain of interest is already covered and models can be shared and passed from software to software without recoding them. Until recently the last stage of the process, the pharmacometric analysis used in clinical studies carried out on subject populations, lacked such an exchange medium. We describe a new emerging exchange format in Pharmacometrics which covers the non-linear mixed effects models, the standard statistical model type used in this area. By interfacing these two formats the entire domain can be covered by complementary standards and subsequently the according tools.

  6. Hybrid Concurrent Constraint Simulation Models of Several Systems

    NASA Technical Reports Server (NTRS)

    Sweet, Adam

    2003-01-01

    This distribution contains several simulation models created for the hybrid simulation language, Hybrid Concurrent Constraint (HCC). An HCC model contains the information specified in the widely-accepted academic definition of a hybrid system: this includes expressions for the modes of the systems to be simulated and the differential equations that apply in each mode. These expressions are written in the HCC syntax. The models included here were created by either applying basic physical laws or implementing equations listed in previously published papers.

  7. Simulating Massive Conformation Changes within Polypeptide Systems

    NASA Astrophysics Data System (ADS)

    Singh, Jaspinder Paul

    In this dissertation I employ all-atom structure based models with stable energy basins to several existing and novel polypeptide systems (postulated conformation changes of the mammalian prion protein and structurally dual proteins). The common themes are finding unfolding and refolding pathways between highly dissimilar protein structures as a means of understanding exactly how and why a protein may misfold. The modeling is based on the energy funnel landscape theory of protein conformation space. The principle of minimal frustration is considered as the model includes parameters which vary the roughness of the landscape and give rise to off-pathway misfoldings. The dual basin model is applied to the C-terminal (residues 166-226) of the mammalian prion protein. One basin represents the known alpha-helical (aH) structure while the other represents the same residues in a lefthanded beta-helical (LHBH) conformation. The LHBH structure has been proposed to help describe one class of in vitro grown fibrils, as well as possibly self-templating the conversion of normal cellular prion protein to the infectious form. Yet, it is unclear how the protein may make this global rearrangement. Our results demonstrate that the conformation changes are not strongly limited by large-scale geometry modification and that there may exist an overall preference for the LHBH conformation. Furthermore, our model presents novel intermediate trapping conformations with twisted LHBH structure. Polypeptides that display structural duality have primary structures that can give rise to different potential native conformations. We apply the structure-based all-atom model to a leucine zipper protein template with a stable aH structure that has been shown in experiment to switch to a β hairpin structure when exposed to a low-pH environment. We show that the model can be used to perform large-scale temperature-dependent conformational switching by simulating this switching behavior. We augmented

  8. Research in Modeling and Simulation for Airspace Systems Innovation

    NASA Technical Reports Server (NTRS)

    Ballin, Mark G.; Kimmel, William M.; Welch, Sharon S.

    2007-01-01

    This viewgraph presentation provides an overview of some of the applied research and simulation methodologies at the NASA Langley Research Center that support aerospace systems innovation. Risk assessment methodologies, complex systems design and analysis methodologies, and aer ospace operations simulations are described. Potential areas for future research and collaboration using interactive and distributed simula tions are also proposed.

  9. An Integrated Design and Development System for Graphics Simulation.

    ERIC Educational Resources Information Center

    Richardson, J. Jeffrey

    In the training of maintenance and operations technicians, three enhancements to a basic, straightforward, fixed-sequence simulation system can be useful. The primary advantage of the resultant system is that the principal object of simulation is the task to be performed, which includes both the planning knowledge and the equipment actions…

  10. Channel simulation for direct-detection optical communication systems

    NASA Technical Reports Server (NTRS)

    Tycz, M.; Fitzmaurice, M. W.

    1974-01-01

    A technique is described for simulating the random modulation imposed by atmospheric scintillation and transmitter pointing jitter on a direct-detection optical communication system. The system is capable of providing signal fading statistics which obey log-normal, beta, Rayleigh, Ricean, or chi-square density functions. Experimental tests of the performance of the channel simulator are presented.

  11. Channel simulation for direct detection optical communication systems

    NASA Technical Reports Server (NTRS)

    Tycz, M.; Fitzmaurice, M. W.

    1974-01-01

    A technique is described for simulating the random modulation imposed by atmospheric scintillation and transmitter pointing jitter on a direct detection optical communication system. The system is capable of providing signal fading statistics which obey log normal, beta, Rayleigh, Ricean or chi-squared density functions. Experimental tests of the performance of the Channel Simulator are presented.

  12. Evaluating the Effectiveness of Information Retrieval Systems Using Simulated Queries.

    ERIC Educational Resources Information Center

    Gordon, Michael D.

    1990-01-01

    Describes a simulation method for estimating recall and fallout in a document retrieval system. Earlier research on simulating document retrieval systems is reviewed, examples are presented of the current method, a probabilistic justification of the method is given, theoretical concerns dealing with retrieval precision are discussed, and further…

  13. The Role of Crop Systems Simulation in Agriculture and Environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the past 30 to 40 years, simulation of crop systems has advanced from a neophyte science with inadequate computing power into a robust and increasingly accepted science supported by improved software, languages, development tools, and computer capabilities. Crop system simulators contain mathe...

  14. Numerical Propulsion System Simulation (NPSS): An Award Winning Propulsion System Simulation Tool

    NASA Technical Reports Server (NTRS)

    Stauber, Laurel J.; Naiman, Cynthia G.

    2002-01-01

    The Numerical Propulsion System Simulation (NPSS) is a full propulsion system simulation tool used by aerospace engineers to predict and analyze the aerothermodynamic behavior of commercial jet aircraft, military applications, and space transportation. The NPSS framework was developed to support aerospace, but other applications are already leveraging the initial capabilities, such as aviation safety, ground-based power, and alternative energy conversion devices such as fuel cells. By using the framework and developing the necessary components, future applications that NPSS could support include nuclear power, water treatment, biomedicine, chemical processing, and marine propulsion. NPSS will dramatically reduce the time, effort, and expense necessary to design and test jet engines. It accomplishes that by generating sophisticated computer simulations of an aerospace object or system, thus enabling engineers to "test" various design options without having to conduct costly, time-consuming real-life tests. The ultimate goal of NPSS is to create a numerical "test cell" that enables engineers to create complete engine simulations overnight on cost-effective computing platforms. Using NPSS, engine designers will be able to analyze different parts of the engine simultaneously, perform different types of analysis simultaneously (e.g., aerodynamic and structural), and perform analysis in a more efficient and less costly manner. NPSS will cut the development time of a new engine in half, from 10 years to 5 years. And NPSS will have a similar effect on the cost of development: new jet engines will cost about a billion dollars to develop rather than two billion. NPSS is also being applied to the development of space transportation technologies, and it is expected that similar efficiencies and cost savings will result. Advancements of NPSS in fiscal year 2001 included enhancing the NPSS Developer's Kit to easily integrate external components of varying fidelities, providing

  15. Isotope heat source simulator for testing of space power systems

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Smith, R. B.

    1973-01-01

    A reliable isotope heat source simulator was designed for use in a Brayton power system. This simulator is composed of an electrically heated tungsten wire which is wound around a boron nitride core and enclosed in a graphite jacket. Simulator testing was performed at the expected operating temperature of the Brayton power system. Endurance testing for 5012 hours was followed by cycling the simulator temperature. The integrity of this simulator was maintained throughout testing. Alumina beads served as a diffusion barrier to prevent interaction between the tungsten heater and boron nitride core. The simulator was designed to maintain a surface temperature of 1311 to 1366 K (1900 to 2000 F) with a power input of approximately 400 watts. The design concept and the materials used in the simulator make possible man different geometries. This flexibility increases its potential use.

  16. Observing system simulation experiments at NASA. Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Atlas, R.; Kalnay, E.; Baker, W. E.; Susskind, J.; Reuter, D.; Halem, M.

    1985-01-01

    A series of realistic simulation studies is being conducted as a cooperative effort between the European Centre for Medium Range Weather Forecasts (ECMWF), the National Meteorological Center (NMC), and the Goddard Laboratory for Atmospheres (GLA), to provide a quantitative assessment of the potential impact of future observing systems on large scale numerical weather prediction. A special objective is to avoid the unrealistic character of earlier simulation studies. Following a brief review of previous simulation studies and real data impact tests, the methodology for the current simulation system will be described. Results from an assessment of the realism of the simulation system and of the potential impact of advanced observing systems on numerical weather prediction and preliminary results utilizing this system will be presented at the conference.

  17. Aeroelastic-Acoustics Simulation of Flight Systems

    NASA Technical Reports Server (NTRS)

    Gupta, kajal K.; Choi, S.; Ibrahim, A.

    2009-01-01

    This paper describes the details of a numerical finite element (FE) based analysis procedure and a resulting code for the simulation of the acoustics phenomenon arising from aeroelastic interactions. Both CFD and structural simulations are based on FE discretization employing unstructured grids. The sound pressure level (SPL) on structural surfaces is calculated from the root mean square (RMS) of the unsteady pressure and the acoustic wave frequencies are computed from a fast Fourier transform (FFT) of the unsteady pressure distribution as a function of time. The resulting tool proves to be unique as it is designed to analyze complex practical problems, involving large scale computations, in a routine fashion.

  18. System Simulation by Recursive Feedback: Coupling a Set of Stand-Alone Subsystem Simulations

    NASA Technical Reports Server (NTRS)

    Nixon, D. D.

    2001-01-01

    Conventional construction of digital dynamic system simulations often involves collecting differential equations that model each subsystem, arran g them to a standard form, and obtaining their numerical gin solution as a single coupled, total-system simultaneous set. Simulation by numerical coupling of independent stand-alone subsimulations is a fundamentally different approach that is attractive because, among other things, the architecture naturally facilitates high fidelity, broad scope, and discipline independence. Recursive feedback is defined and discussed as a candidate approach to multidiscipline dynamic system simulation by numerical coupling of self-contained, single-discipline subsystem simulations. A satellite motion example containing three subsystems (orbit dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Distributed and centralized implementations of coupling have been considered. Numerical results are evaluated by direct comparison with a standard total-system, simultaneous-solution approach.

  19. Mathematical simulation of power conditioning systems. Volume 1: Simulation of elementary units. Report on simulation methodology

    NASA Technical Reports Server (NTRS)

    Prajous, R.; Mazankine, J.; Ippolito, J. C.

    1978-01-01

    Methods and algorithms used for the simulation of elementary power conditioning units buck, boost, and buck-boost, as well as shunt PWM are described. Definitions are given of similar converters and reduced parameters. The various parts of the simulation to be carried out are dealt with; local stability, corrective network, measurements of input-output impedance and global stability. A simulation example is given.

  20. Simulating Hepatic Lesions as Virtual Cellular Systems

    EPA Science Inventory

    The US EPA Virtual Liver (v-Liver) project is aimed at reducing the uncertainty in estimating the risk of toxic outcomes in humans by simulating the dose-dependent effects of environmental chemicals in silico. The v-Liver embodies an emerging field of research in computational ti...

  1. An Open Simulation System Model for Scientific Applications

    NASA Technical Reports Server (NTRS)

    Williams, Anthony D.

    1995-01-01

    A model for a generic and open environment for running multi-code or multi-application simulations - called the open Simulation System Model (OSSM) - is proposed and defined. This model attempts to meet the requirements of complex systems like the Numerical Propulsion Simulator System (NPSS). OSSM places no restrictions on the types of applications that can be integrated at any state of its evolution. This includes applications of different disciplines, fidelities, etc. An implementation strategy is proposed that starts with a basic prototype, and evolves over time to accommodate an increasing number of applications. Potential (standard) software is also identified which may aid in the design and implementation of the system.

  2. Development of a Prototype Simulation Executive with Zooming in the Numerical Propulsion System Simulation

    NASA Technical Reports Server (NTRS)

    Reed, John A.; Afjeh, Abdollah A.

    1995-01-01

    A major difficulty in designing aeropropulsion systems is that of identifying and understanding the interactions between the separate engine components and disciplines (e.g., fluid mechanics, structural mechanics, heat transfer, material properties, etc.). The traditional analysis approach is to decompose the system into separate components with the interaction between components being evaluated by the application of each of the single disciplines in a sequential manner. Here, one discipline uses information from the calculation of another discipline to determine the effects of component coupling. This approach, however, may not properly identify the consequences of these effects during the design phase, leaving the interactions to be discovered and evaluated during engine testing. This contributes to the time and cost of developing new propulsion systems as, typically, several design-build-test cycles are needed to fully identify multidisciplinary effects and reach the desired system performance. The alternative to sequential isolated component analysis is to use multidisciplinary coupling at a more fundamental level. This approach has been made more plausible due to recent advancements in computation simulation along with application of concurrent engineering concepts. Computer simulation systems designed to provide an environment which is capable of integrating the various disciplines into a single simulation system have been proposed and are currently being developed. One such system is being developed by the Numerical Propulsion System Simulation (NPSS) project. The NPSS project, being developed at the Interdisciplinary Technology Office at the NASA Lewis Research Center is a 'numerical test cell' designed to provide for comprehensive computational design and analysis of aerospace propulsion systems. It will provide multi-disciplinary analyses on a variety of computational platforms, and a user-interface consisting of expert systems, data base management and

  3. Large liquid rocket engine transient performance simulation system

    NASA Technical Reports Server (NTRS)

    Mason, J. R.; Southwick, R. D.

    1991-01-01

    A simulation system, ROCETS, was designed and developed to allow cost-effective computer predictions of liquid rocket engine transient performance. The system allows a user to generate a simulation of any rocket engine configuration using component modules stored in a library through high-level input commands. The system library currently contains 24 component modules, 57 sub-modules and maps, and 33 system routines and utilities. FORTRAN models from other sources can be operated in the system upon inclusion of interface information on comment cards. Operation of the simulation is simplified for the user by run, execution, and output processors. The simulation system makes available steady-state trim balance, transient operation, and linear partial generation. The system utilizes a modern equation solver for efficient operation of the simulations. Transient integration methods include integral and differential forms for the trapezoidal, first order Gear, and second order Gear corrector equations. A detailed technology test bed engine (TTBE) model was generated to be used as the acceptance test of the simulation system. The general level of model detail was that reflected in the Space Shuttle Main Engine DTM. The model successfully obtained steady-state balance in main stage operation and simulated throttle transients, including engine starts and shutdown. A NASA FORTRAN control model was obtained, ROCETS interface installed in comment cards, and operated with the TTBE model in closed-loop transient mode.

  4. Expert System Architecture for Rocket Engine Numerical Simulators: A Vision

    NASA Technical Reports Server (NTRS)

    Mitra, D.; Babu, U.; Earla, A. K.; Hemminger, Joseph A.

    1998-01-01

    Simulation of any complex physical system like rocket engines involves modeling the behavior of their different components using mostly numerical equations. Typically a simulation package would contain a set of subroutines for these modeling purposes and some other ones for supporting jobs. A user would create an input file configuring a system (part or whole of a rocket engine to be simulated) in appropriate format understandable by the package and run it to create an executable module corresponding to the simulated system. This module would then be run on a given set of input parameters in another file. Simulation jobs are mostly done for performance measurements of a designed system, but could be utilized for failure analysis or a design job such as inverse problems. In order to use any such package the user needs to understand and learn a lot about the software architecture of the package, apart from being knowledgeable in the target domain. We are currently involved in a project in designing an intelligent executive module for the rocket engine simulation packages, which would free any user from this burden of acquiring knowledge on a particular software system. The extended abstract presented here will describe the vision, methodology and the problems encountered in the project. We are employing object-oriented technology in designing the executive module. The problem is connected to the areas like the reverse engineering of any simulation software, and the intelligent systems for simulation.

  5. A verilog simulation of the CDF DAQ system

    SciTech Connect

    Schurecht, K.; Harris, R.; Sinervo, P.; Grindley, R.

    1991-11-01

    A behavioral simulation of the CDF data acquisition system was written in the Verilog modeling language in order to investigate the effects of various improvements to the existing system. This system is modeled as five separate components that communicate with each other via Fastbus interrupt messages. One component of the system, the CDF event builder, is modeled in substantially greater detail due to its complex structure. This simulation has been verified by comparing its performance with that of the existing DAQ system. Possible improvements to the existing systems were studied using the simulation, and the optimal upgrade path for the system was chosen on the basis of these studies. The overall throughput of the modified system is estimated to be double that of the existing setup. Details of this modeling effort will be discussed, including a comparison of the modeled and actual performance of the existing system.

  6. Simulation System Optimization for Rotorcraft Research on the Vertical Motion Simulator

    NASA Technical Reports Server (NTRS)

    Beard, Steven D.; Reardon, Scott; Tobias, Eric Luke; Aponso, Bimal Lalith

    2012-01-01

    A handling qualities experiment was run on the Vertical Motion Simulator using the GenHel math model configured for a UH60A Blackhawk helicopter. In order to obtain valid handling qualities ratings, the simulation system including the math model were optimized to provide realistic cues. The aircraft math model was adjusted to account for the simulator motion system delays and the motion systems gains and washouts were tuned for the bob-up, precision hover and sidestep tasks. The handling qualities ratings from this experiment showed good correlation to flight ratings.

  7. FEM Simulation of Small Wind Power Generating System Using PMSG

    NASA Astrophysics Data System (ADS)

    Kesamaru, Katsumi; Ohno, Yoshihiro; Sonoda, Daisuke

    The paper describes a new approach to simulate the small wind power generating systems using PMSG, in which the output is connected to constant resistive load, such as heaters, through the rectifier and the dc chopper. The dynamics of the wind power generating system is presented, and it is shown by simulation results that this approach is useful for system dynamics, such as starting phenomena.

  8. Hybrid and Electric Advanced Vehicle Systems Simulation

    NASA Technical Reports Server (NTRS)

    Beach, R. F.; Hammond, R. A.; Mcgehee, R. K.

    1985-01-01

    Predefined components connected to represent wide variety of propulsion systems. Hybrid and Electric Advanced Vehicle System (HEAVY) computer program is flexible tool for evaluating performance and cost of electric and hybrid vehicle propulsion systems. Allows designer to quickly, conveniently, and economically predict performance of proposed drive train.

  9. A flight simulator control system using electric torque motors

    NASA Technical Reports Server (NTRS)

    Musick, R. O.; Wagner, C. A.

    1975-01-01

    Control systems are required in flight simulators to provide representative stick and rudder pedal characteristics. A system has been developed that uses electric dc torque motors instead of the more common hydraulic actuators. The torque motor system overcomes certain disadvantages of hydraulic systems, such as high cost, high power consumption, noise, oil leaks, and safety problems. A description of the torque motor system is presented, including both electrical and mechanical design as well as performance characteristics. The system develops forces sufficiently high for most simulations, and is physically small and light enough to be used in most motion-base cockpits.

  10. Predicting System Accidents with Model Analysis During Hybrid Simulation

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Fleming, Land D.; Throop, David R.

    2002-01-01

    Standard discrete event simulation is commonly used to identify system bottlenecks and starving and blocking conditions in resources and services. The CONFIG hybrid discrete/continuous simulation tool can simulate such conditions in combination with inputs external to the simulation. This provides a means for evaluating the vulnerability to system accidents of a system's design, operating procedures, and control software. System accidents are brought about by complex unexpected interactions among multiple system failures , faulty or misleading sensor data, and inappropriate responses of human operators or software. The flows of resource and product materials play a central role in the hazardous situations that may arise in fluid transport and processing systems. We describe the capabilities of CONFIG for simulation-time linear circuit analysis of fluid flows in the context of model-based hazard analysis. We focus on how CONFIG simulates the static stresses in systems of flow. Unlike other flow-related properties, static stresses (or static potentials) cannot be represented by a set of state equations. The distribution of static stresses is dependent on the specific history of operations performed on a system. We discuss the use of this type of information in hazard analysis of system designs.

  11. The Center-TRACON Automation System: Simulation and field testing

    NASA Technical Reports Server (NTRS)

    Denery, Dallas G.; Erzberger, Heinz

    1995-01-01

    A new concept for air traffic management in the terminal area, implemented as the Center-TRACON Automation System, has been under development at NASA Ames in a cooperative program with the FAA since 1991. The development has been strongly influenced by concurrent simulation and field site evaluations. The role of simulation and field activities in the development process will be discussed. Results of recent simulation and field tests will be presented.

  12. Reactor Subsystem Simulation for Nuclear Hybrid Energy Systems

    SciTech Connect

    Shannon Bragg-Sitton; J. Michael Doster; Alan Rominger

    2012-09-01

    Preliminary system models have been developed by Idaho National Laboratory researchers and are currently being enhanced to assess integrated system performance given multiple sources (e.g., nuclear + wind) and multiple applications (i.e., electricity + process heat). Initial efforts to integrate a Fortran-based simulation of a small modular reactor (SMR) with the balance of plant model have been completed in FY12. This initial effort takes advantage of an existing SMR model developed at North Carolina State University to provide initial integrated system simulation for a relatively low cost. The SMR subsystem simulation details are discussed in this report.

  13. Simulation test beds for the space station electrical power system

    NASA Technical Reports Server (NTRS)

    Sadler, Gerald G.

    1988-01-01

    NASA Lewis Research Center and its prime contractor are responsible for developing the electrical power system on the space station. The power system will be controlled by a network of distributed processors. Control software will be verified, validated, and tested in hardware and software test beds. Current plans for the software test bed involve using real time and nonreal time simulations of the power system. This paper will discuss the general simulation objectives and configurations, control architecture, interfaces between simulator and controls, types of tests, and facility configurations.

  14. Simulation test beds for the Space Station electrical power system

    NASA Technical Reports Server (NTRS)

    Sadler, Gerald G.

    1988-01-01

    NASA Lewis Research Center and its prime contractor are respnsible for developing the electrical power system on the Space Station. The power system will be controlled by a network of distributed processors. Control software will be verified, validated, and tested in hardware and software test beds. Current plans for the software test bed involve using real time and nonreal time simulations of the power system. This paper will discuss the general simulation objectives and configurations, control architecture, interfaces between simulator and controls, types of tests, and facility configurations.

  15. Issues in visual support to real-time space system simulation solved in the Systems Engineering Simulator

    NASA Technical Reports Server (NTRS)

    Yuen, Vincent K.

    1989-01-01

    The Systems Engineering Simulator has addressed the major issues in providing visual data to its real-time man-in-the-loop simulations. Out-the-window views and CCTV views are provided by three scene systems to give the astronauts their real-world views. To expand the window coverage for the Space Station Freedom workstation a rotating optics system is used to provide the widest field of view possible. To provide video signals to as many viewpoints as possible, windows and CCTVs, with a limited amount of hardware, a video distribution system has been developed to time-share the video channels among viewpoints at the selection of the simulation users. These solutions have provided the visual simulation facility for real-time man-in-the-loop simulations for the NASA space program.

  16. Environmental fog/rain visual display system for aircraft simulators

    NASA Technical Reports Server (NTRS)

    Chase, W. D. (Inventor)

    1982-01-01

    An environmental fog/rain visual display system for aircraft simulators is described. The electronic elements of the system include a real time digital computer, a caligraphic color display which simulates landing lights of selective intensity, and a color television camera for producing a moving color display of the airport runway as depicted on a model terrain board. The mechanical simulation elements of the system include an environmental chamber which can produce natural fog, nonhomogeneous fog, rain and fog combined, or rain only. A pilot looking through the aircraft wind screen will look through the fog and/or rain generated in the environmental chamber onto a viewing screen with the simulated color image of the airport runway thereon, and observe a very real simulation of actual conditions of a runway as it would appear through actual fog and/or rain.

  17. Multiscale simulation of soft matter systems.

    PubMed

    Peter, Christine; Kremer, Kurt

    2010-01-01

    This paper gives a short introduction to multiscale simulation approaches in soft matter science. This paper is based on and extended from a previous review. (1. C. Peter and K. Kremer, Soft Matter, 2009, DOI:10.1039/b912027k.) It also includes a discussion of aspects of soft matter in general and a short account of one of the historically underlying concepts, namely renormalization group theory. Some different concepts and several typical problems are shortly addressed, including a (more personal) view on challenges and chances.

  18. Simulation of Combustion Systems with Realistic g-jitter

    NASA Technical Reports Server (NTRS)

    Mell, William E.; McGrattan, Kevin B.; Baum, Howard R.

    2003-01-01

    In this project a transient, fully three-dimensional computer simulation code was developed to simulate the effects of realistic g-jitter on a number of combustion systems. The simulation code is capable of simulating flame spread on a solid and nonpremixed or premixed gaseous combustion in nonturbulent flow with simple combustion models. Simple combustion models were used to preserve computational efficiency since this is meant to be an engineering code. Also, the use of sophisticated turbulence models was not pursued (a simple Smagorinsky type model can be implemented if deemed appropriate) because if flow velocities are large enough for turbulence to develop in a reduced gravity combustion scenario it is unlikely that g-jitter disturbances (in NASA's reduced gravity facilities) will play an important role in the flame dynamics. Acceleration disturbances of realistic orientation, magnitude, and time dependence can be easily included in the simulation. The simulation algorithm was based on techniques used in an existing large eddy simulation code which has successfully simulated fire dynamics in complex domains. A series of simulations with measured and predicted acceleration disturbances on the International Space Station (ISS) are presented. The results of this series of simulations suggested a passive isolation system and appropriate scheduling of crew activity would provide a sufficiently "quiet" acceleration environment for spherical diffusion flames.

  19. Numerical simulations of the thermoacoustic computed tomography breast imaging system

    NASA Astrophysics Data System (ADS)

    Kiser, William Lester, Jr.

    A thermoacoustic wave is produced when an object absorbs energy and experiences a subsequent thermal expansion. We have developed a Thermoacoustic Computed Tomography (TACT) breast imaging system to exploit the thermoacoustic phenomena as a method of soft tissue imaging. By exposing the breast to short pulses of 434 MHz microwaves, ultrasonic pulses are generated and detected with a hemispherical transducer array submersed in a water bath. Filtering and back projecting the transducer signals generates a 3-D image that maps the localized microwave absorption properties of the breast. In an effort to understand the factors limiting image quality, the TACT system was numerically simulated. The simulations were used to generate the transducer signals that would be collected by the TACT system during a scan of an object. These simulated data streams were then fed into the system image reconstruction software to provide images of simulated phantoms. The effects of transducer diameter, transducer response, transducer array geometry and stimulating pulse width on the spatial and contrast resolution of the system were quantified using the simulations. The spatial resolution was highly dependent upon location in the imaging volume. This was due to the off axis response of transducers of finite aperture. Simulated data were compared with experimental data, obtained by imaging a parallel-piped resolution phantom, to verify the accuracy of the simulation code. A contrast-detail phantom was numerically simulated to determine the ability of the system to image spheres of diameters <1 cm with absorption values on the order of physiologic saline, when located in a background of noise. The results of the contrast-detail analysis were dependent on the location of the spheres in the imaging volume and the diameter of the simulated transducers. This work sets the foundation for the initial image quality studies of the TACT system. Improvements to the current imaging system, based on

  20. Studies and simulations of the DigiCipher system

    NASA Technical Reports Server (NTRS)

    Sayood, K.; Chen, Y. C.; Kipp, G.

    1993-01-01

    During this period the development of simulators for the various high definition television (HDTV) systems proposed to the FCC was continued. The FCC has indicated that it wants the various proposers to collaborate on a single system. Based on all available information this system will look very much like the advanced digital television (ADTV) system with major contributions only from the DigiCipher system. The results of our simulations of the DigiCipher system are described. This simulator was tested using test sequences from the MPEG committee. The results are extrapolated to HDTV video sequences. Once again, some caveats are in order. The sequences used for testing the simulator and generating the results are those used for testing the MPEG algorithm. The sequences are of much lower resolution than the HDTV sequences would be, and therefore the extrapolations are not totally accurate. One would expect to get significantly higher compression in terms of bits per pixel with sequences that are of higher resolution. However, the simulator itself is a valid one, and should HDTV sequences become available, they could be used directly with the simulator. A brief overview of the DigiCipher system is given. Some coding results obtained using the simulator are looked at. These results are compared to those obtained using the ADTV system. These results are evaluated in the context of the CCSDS specifications and make some suggestions as to how the DigiCipher system could be implemented in the NASA network. Simulations such as the ones reported can be biased depending on the particular source sequence used. In order to get more complete information about the system one needs to obtain a reasonable set of models which mirror the various kinds of sources encountered during video coding. A set of models which can be used to effectively model the various possible scenarios is provided. As this is somewhat tangential to the other work reported, the results are included as an

  1. System-of-Systems Approach for Integrated Energy Systems Modeling and Simulation: Preprint

    SciTech Connect

    Mittal, Saurabh; Ruth, Mark; Pratt, Annabelle; Lunacek, Monte; Krishnamurthy, Dheepak; Jones, Wesley

    2015-08-21

    Today’s electricity grid is the most complex system ever built—and the future grid is likely to be even more complex because it will incorporate distributed energy resources (DERs) such as wind, solar, and various other sources of generation and energy storage. The complexity is further augmented by the possible evolution to new retail market structures that provide incentives to owners of DERs to support the grid. To understand and test new retail market structures and technologies such as DERs, demand-response equipment, and energy management systems while providing reliable electricity to all customers, an Integrated Energy System Model (IESM) is being developed at NREL. The IESM is composed of a power flow simulator (GridLAB-D), home energy management systems implemented using GAMS/Pyomo, a market layer, and hardware-in-the-loop simulation (testing appliances such as HVAC, dishwasher, etc.). The IESM is a system-of-systems (SoS) simulator wherein the constituent systems are brought together in a virtual testbed. We will describe an SoS approach for developing a distributed simulation environment. We will elaborate on the methodology and the control mechanisms used in the co-simulation illustrated by a case study.

  2. ROBOSIM: An intelligent simulator for robotic systems

    NASA Technical Reports Server (NTRS)

    Fernandez, Kenneth R.; Cook, George E.; Biegl, Csaba; Springfield, James F.

    1993-01-01

    The purpose of this paper is to present an update of an intelligent robotics simulator package, ROBOSIM, first introduced at Technology 2000 in 1990. ROBOSIM is used for three-dimensional geometrical modeling of robot manipulators and various objects in their workspace, and for the simulation of action sequences performed by the manipulators. Geometric modeling of robot manipulators has an expanding area of interest because it can aid the design and usage of robots in a number of ways, including: design and testing of manipulators, robot action planning, on-line control of robot manipulators, telerobotic user interface, and training and education. NASA developed ROBOSIM between 1985-88 to facilitate the development of robotics, and used the package to develop robotics for welding, coating, and space operations. ROBOSIM has been further developed for academic use by its co-developer Vanderbilt University, and has been in both classroom and laboratory environments for teaching complex robotic concepts. Plans are being formulated to make ROBOSIM available to all U.S. engineering/engineering technology schools (over three hundred total with an estimated 10,000+ users per year).

  3. Rigorous electromagnetic simulation applied to alignment systems

    NASA Astrophysics Data System (ADS)

    Deng, Yunfei; Pistor, Thomas V.; Neureuther, Andrew R.

    2001-09-01

    Rigorous electromagnetic simulation with TEMPEST is used to provide benchmark data and understanding of key parameters in the design of topographical features of alignment marks. Periodic large silicon trenches are analyzed as a function of wavelength (530-800 nm), duty cycle, depth, slope and angle of incidence. The signals are well behaved except when the trench width becomes about 1 micrometers or smaller. Segmentation of the trenches to form 3D marks shows that a segmentation period of 2-5 wavelengths makes the diffraction in the (1,1) direction about 1/3 to 1/2 of that in the main first order (1,0). Transmission alignment marks nanoimprint lithography using the difference between the +1 and -1 reflected orders showed a sensitivity of the difference signal to misalignment of 0.7%/nm for rigorous simulation and 0.5%/nm for simple ray-tracing. The sensitivity to a slanted substrate indentation was 10 nm off-set per degree of tilt from horizontal.

  4. Simulation studies of improved sounding systems

    NASA Technical Reports Server (NTRS)

    Yates, H.; Wark, D.; Aumann, H.; Evans, N.; Phillips, N.; Susskind, J.; Mcmillin, L.; Goldman, A.; Chahine, M.; Crone, L.

    1989-01-01

    Two instrument designs for indirect satellite sounding of the atmosphere in the infrared are represented by the High Resolution Infra-Red Sounder, Model 2 (HIRS-2) and by the Advanced Meteorological Temperature Sounder (AMTS). The relative capabilities of the two instruments were tested by simulating satellite measurements from a group of temperature soundings, allowing the two participants to retrieve the temperature profiles from the simulated data, and comparing the results with the original temperature profiles. Four data sets were produced from radiosondes data extrapolated to a suitable altitude, representing continents and oceans, between 30S and 30N. From the information available, temperature profiles were retrieved by two different methods, statistical regression and inversion of the radiative transfer equation. Results show the consequence of greater spectral purity, concomitant increase in the number of spectral intervals, and the better spatial resolution in partly clouded areas. At the same time, the limitation of the HIRS-2 without its companion instrument leads to some results which should be ignored in comparing the two instruments. A clear superiority of AMTS results is shown.

  5. General Aviation Cockpit Weather Information System Simulation Studies

    NASA Technical Reports Server (NTRS)

    McAdaragh, Ray; Novacek, Paul

    2003-01-01

    This viewgraph presentation provides information on two experiments on the effectiveness of a cockpit weather information system on a simulated general aviation flight. The presentation covers the simulation hardware configuration, the display device screen layout, a mission scenario, conclusions, and recommendations. The second experiment, with its own scenario and conclusions, is a follow-on experiment.

  6. Tidal simulation using regional ocean modeling systems (ROMS)

    NASA Technical Reports Server (NTRS)

    Wang, Xiaochun; Chao, Yi; Li, Zhijin; Dong, Changming; Farrara, John; McWilliams, James C.; Shum, C. K.; Wang, Yu; Matsumoto, Koji; Rosenfeld, Leslie K.; Paduan, Jeffrey D.

    2006-01-01

    The purpose of our research is to test the capability of ROMS in simulating tides. The research also serves as a necessary exercise to implement tides in an operational ocean forecasting system. In this paper, we emphasize the validation of the model tide simulation. The characteristics and energetics of tides of the region will be reported in separate publications.

  7. Simulation of diurnal thermal energy storage systems: Preliminary results

    SciTech Connect

    Katipamula, S.; Somasundaram, S.; Williams, H.R.

    1994-12-01

    This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system, and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

  8. Simulation of diurnal thermal energy storage systems: Preliminary results

    NASA Astrophysics Data System (ADS)

    Katipamula, S.; Somasundaram, S.; Williams, H. R.

    1994-12-01

    This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system; and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

  9. KBSIM: a system for interactive knowledge-based simulation.

    PubMed

    Hakman, M; Groth, T

    1991-01-01

    The KBSIM system integrates quantitative simulation with symbolic reasoning techniques, under the control of a user interface management system, using a relational database management system for data storage and interprocess communication. The system stores and processes knowledge from three distinct knowledge domains, viz. (i) knowledge about the processes of the system under investigation, expressed in terms of a Continuous System Simulation Language (CSSL); (ii) heuristic knowledge on how to reach the goals of the simulation experiment, expressed in terms of a Rule Description Language (RDL); and (iii) knowledge about the requirements of the intended users, expressed in terms of a User Interface Description Language (UIDL). The user works in an interactive environment controlling the simulation course with use of a mouse and a large screen containing a set of 'live' charts and forms. The user is assisted by an embedded 'expert system' module continuously watching both the system's behavior and the user's action, and producing alerts, alarms, comments and advice. The system was developed on a Hewlett-Packard 9000/350 workstation under the HP-Unix and HP-Windows operating systems, using the MIMER database management system, and Fortran, Prolog/Lisp and C as implementation languages. The KBSIM system has great potentials for supporting problem solving, design of working procedures and teaching related to management of highly dynamic systems. PMID:2060297

  10. System Simulation by Recursive Feedback: Coupling A Set of Stand-Alone Subsystem Simulations

    NASA Technical Reports Server (NTRS)

    Nixon, Douglas D.; Hanson, John M. (Technical Monitor)

    2002-01-01

    Recursive feedback is defined and discussed as a framework for development of specific algorithms and procedures that propagate the time-domain solution for a dynamical system simulation consisting of multiple numerically coupled self-contained stand-alone subsystem simulations. A satellite motion example containing three subsystems (other dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Centralized and distributed versions of coupling structure have been addressed. Numerical results are evaluated by direct comparison with a standard total-system simultaneous-solution approach.

  11. System Simulation by Recursive Feedback: Coupling a Set of Stand-Alone Subsystem Simulations

    NASA Technical Reports Server (NTRS)

    Nixon, Douglas D.; Ryan, Stephen G. (Technical Monitor)

    2002-01-01

    Recursive feedback is defined and discussed as a framework for development of specific algorithms and procedures that propagate the time-domain solution for a dynamical system simulation consisting of multiple numerically coupled, self-contained, stand-alone subsystem simulations. A satellite motion example containing three subsystems (orbit dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Centralized and distributed versions of coupling structure have been addressed. Numerical results are evaluated by direct comparison with a standard total-system, simultaneous-solution approach.

  12. Software systems testing of a closed loop tracking system using a SIMULINK-based simulation

    NASA Astrophysics Data System (ADS)

    Robinson, Brendan; Sasaki, Doreen M.

    2000-07-01

    This paper discuses a simulation approach that has streamlined the real-time software development process for a closed loop image-based tracking system. The MATLAB/SIMULINK simulation consists of elements constructed from common source modules shared with the deliverable system. The simulation has provided a tool to support algorithm development for the fundamental system components, including a system controller, a servo controller, and an image processor. In addition, the simulation has provided a testbed for verification of system performance. The context for this application is the low rate initial production phase of a tactical airborne avionics system that includes an image-based tracking system.

  13. Simulating satellite infrared sounding retrievals in support of Observing System Simulation Experiments (OSSEs)

    NASA Astrophysics Data System (ADS)

    Pagano, Thomas S.; Mathews, William; Irion, Frederick W.; Sturm, Erick J.

    2014-09-01

    A new set of Observing System Simulation Experiments (OSSEs) are underway to assess the impact of higher spatial and temporal resolution sounding on hurricane forecast accuracy. To support these studies, we have developed an OSSE retrieval simulation system. The system uses a simulated satellite orbit track to provide sample locations and footprint area of the infrared sounder configuration to be simulated over the region of interest. The data to be sampled are an OSSE nature run developed by the NOAA Atlantic Oceanographic Meteorological Laboratory (AOML) and the University of Miami (UM). The nature run is sampled at the sounder locations and integrated over the sounder footprint area. The resulting averaged profiles are smoothed vertically with simulated averaging kernels for the Atmospheric Infrared Sounder (AIRS) using a linear retrieval simulation to produce calculated temperature and water vapor profiles. With reasonable fidelity, the sampled and smoothed profiles simulate the retrievals we can expect from a sounder like AIRS for the orbit and sampling configurations under test. Three instruments were simulated corresponding to the AIRS 45×45km footprint in LEO, a hypothetical sounder at 2×2km footprint in LEO, and a hypothetical GEO sounder at 5×5km regional and 10km × 10km full disk footprint sizes. RMS error relative to the nature run is calculated to demonstrate the error characteristics of the simulation system. The simulated retrievals as a result of this effort are currently being assessed by NOAA AOML in an OSSE study to determine the impact of advanced hyperspectral infrared sounders on hurricane forecast improvement.

  14. KLASS: Kennedy Launch Academy Simulation System

    NASA Technical Reports Server (NTRS)

    Garner, Lesley C.

    2007-01-01

    Software provides access to many sophisticated scientific instrumentation (Scanning Electron Microscope (SEM), a Light Microscope, a Scanning Probe Microscope (covering Scanning Tunneling, Atomic Force, and Magnetic Force microscopy), and an Energy Dispersive Spectrometer for the SEM). Flash animation videos explain how each of the instruments work. Videos on how they are used at NASA and the sample preparation. Measuring and labeling tools provided with each instrument. Hands on experience of controlling the virtual instrument to conduct investigations, much like the real scientists at NASA do. Very open architecture. Open source on SourceForge. Extensive use of XML Target audience is high school and entry-level college students. "Many beginning students never get closer to an electron microscope than the photos in their textbooks. But anyone can get a sense of what the instrument can do by downloading this simulator from NASA's Kennedy Space Center." Science Magazine, April 8th, 2005

  15. MICROBIOLOGICAL CHARACTERIZATION OF BACTERIA INHABITING A WATER DISTRIBUTION SYSTEM SIMULATOR

    EPA Science Inventory

    The impact of chlorination and chloramination treatments on heterotrophic bacteria (HB) and ammonia oxidizing bacteria (AOB) inhabiting a water distribution system simulator was investigated. Notable changes in bacterial densities were observed during this monitoring study. For e...

  16. Documentation for the token ring network simulation system

    NASA Technical Reports Server (NTRS)

    Peden, Jeffery H.; Weaver, Alfred C.

    1990-01-01

    A manual is presented which describes the language features of the Token Ring Network Simulation System. The simulation system is a powerful simulation tool for token ring networks which allows the specification of various Medium Access Control (MAC) layer protocols as well as the specification of various features of upper layer ISO protocols. In addition to these features, it also allows the user to specify message and station classes virtually to any degree of detail desired. The choice of a language instead of an interactive system to specify network parameters was dictated by both flexibility and time considerations. The language was developed specifically for the simulation system, and is very simple. It is also user friendly in that language elements which do not apply to the case at hand are ignored rather than treated as errors.

  17. School System Simulation: An Effective Model for Educational Leaders.

    ERIC Educational Resources Information Center

    Nelson, Jorge O.

    This study reviews the literature regarding the theoretical rationale for creating a computer-based school system simulation for educational leaders' use in problem solving and decision making. Like all social systems, educational systems are so complex that individuals are hard-pressed to consider all interrelated parts as a totality. A…

  18. A Modular Interactive Simulation System for Eutrophication and Regional Development

    NASA Astrophysics Data System (ADS)

    Fedra, Kurt

    1985-02-01

    An interactive, policy-oriented simulation and information system including videographics is introduced. The system is designed as a tool for learning about large, complex, regional environmental systems. A high degree of flexibility is achieved through the use of simple modules, describing elements of the system at various levels of detail and resolution. Background information from a historical data base drives the default evolution of the system. Alternative courses of action can be simulated at various hierarchical levels of management or policymaking. An interactive, dialogue-oriented, user interface controls the simulations and the display of results, including videographics with geographical or statistical information. The approach is discussed in terms of a pilot application project, dealing with a lake-watershed system having conflicts between water quality and regional development goals.

  19. Configuration Management File Manager Developed for Numerical Propulsion System Simulation

    NASA Technical Reports Server (NTRS)

    Follen, Gregory J.

    1997-01-01

    One of the objectives of the High Performance Computing and Communication Project's (HPCCP) Numerical Propulsion System Simulation (NPSS) is to provide a common and consistent way to manage applications, data, and engine simulations. The NPSS Configuration Management (CM) File Manager integrated with the Common Desktop Environment (CDE) window management system provides a common look and feel for the configuration management of data, applications, and engine simulations for U.S. engine companies. In addition, CM File Manager provides tools to manage a simulation. Features include managing input files, output files, textual notes, and any other material normally associated with simulation. The CM File Manager includes a generic configuration management Application Program Interface (API) that can be adapted for the configuration management repositories of any U.S. engine company.

  20. Laser Doppler velocimeter system simulation for sensing aircraft wake vortices

    NASA Technical Reports Server (NTRS)

    Thomson, J. A. L.; Meng, J. C. S.

    1974-01-01

    A hydrodynamic model of aircraft vortex wakes in an irregular wind shear field near the ground is developed and used as a basis for modeling the characteristics of a laser Doppler detection and vortex location system. The trailing vortex sheet and the wind shear are represented by discrete free vortices distributed over a two-dimensional grid. The time dependent hydrodynamic equations are solved by direct numerical integration in the Boussinesq approximation. The ground boundary is simulated by images, and fast Fourier Transform techniques are used to evaluate the vorticity stream function. The atmospheric turbulence was simulated by constructing specific realizations at time equal to zero, assuming that Kolmogoroff's law applies, and that the dissipation rate is constant throughout the flow field. The response of a simulated laser Doppler velocimeter is analyzed by simulating the signal return from the flow field as sensed by a simulation of the optical/electronic system.

  1. Relating Standardized Visual Perception Measures to Simulator Visual System Performance

    NASA Technical Reports Server (NTRS)

    Kaiser, Mary K.; Sweet, Barbara T.

    2013-01-01

    Human vision is quantified through the use of standardized clinical vision measurements. These measurements typically include visual acuity (near and far), contrast sensitivity, color vision, stereopsis (a.k.a. stereo acuity), and visual field periphery. Simulator visual system performance is specified in terms such as brightness, contrast, color depth, color gamut, gamma, resolution, and field-of-view. How do these simulator performance characteristics relate to the perceptual experience of the pilot in the simulator? In this paper, visual acuity and contrast sensitivity will be related to simulator visual system resolution, contrast, and dynamic range; similarly, color vision will be related to color depth/color gamut. Finally, we will consider how some characteristics of human vision not typically included in current clinical assessments could be used to better inform simulator requirements (e.g., relating dynamic characteristics of human vision to update rate and other temporal display characteristics).

  2. N-body simulations of disks. [of stellar systems

    NASA Technical Reports Server (NTRS)

    Hohl, F.

    1975-01-01

    The methods used in large-scale n-body simulations are discussed. However, the present review concentrates on results already obtained in n-body simulations using systems containing up to 200,000 simulation stars. Results are presented which show that the stability criterion developed for flattened systems applies only to truly axisymmetric instabilities. Purely stellar disks acquire rather large velocity dispersions, generally two or more times the velocity dispersion required by Toomre (1964) for axisymmetric stability. In computer simulations, the bar-forming instability can be prevented only by comparatively large velocity dispersions. However, simulations including the effects of the galactic halo and core as a fixed background field show that bar formation can be prevented for fixed halo components as large or larger than the self-consistent disk component. Experiments performed to determine the collisional relaxation time for large-scale gravitational n-body calculations show that these models are indeed 'collisionless'.

  3. Control system software, simulation, and robotic applications

    NASA Technical Reports Server (NTRS)

    Frisch, Harold P.

    1991-01-01

    All essential existing capabilities needed to create a man-machine interaction dynamics and performance (MMIDAP) capability are reviewed. The multibody system dynamics software program Order N DISCOS will be used for machine and musculo-skeletal dynamics modeling. The program JACK will be used for estimating and animating whole body human response to given loading situations and motion constraints. The basic elements of performance (BEP) task decomposition methodologies associated with the Human Performance Institute database will be used for performance assessment. Techniques for resolving the statically indeterminant muscular load sharing problem will be used for a detailed understanding of potential musculotendon or ligamentous fatigue, pain, discomfort, and trauma. The envisioned capacity is to be used for mechanical system design, human performance assessment, extrapolation of man/machine interaction test data, biomedical engineering, and soft prototyping within a concurrent engineering (CE) system.

  4. Investigations of respiratory control systems simulation

    NASA Technical Reports Server (NTRS)

    Gallagher, R. R.

    1973-01-01

    The Grodins' respiratory control model was investigated and it was determined that the following modifications were necessary before the model would be adaptable for current research efforts: (1) the controller equation must be modified to allow for integration of the respiratory system model with other physiological systems; (2) the system must be more closely correlated to the salient physiological functionings; (3) the respiratory frequency and the heart rate should be expanded to illustrate other physiological relationships and dependencies; and (4) the model should be adapted to particular individuals through a better defined set of initial parameter values in addition to relating these parameter values to the desired environmental conditions. Several of Milhorn's respiratory control models were also investigated in hopes of using some of their features as modifications for Grodins' model.

  5. Simulation of communication line for down hole telemetry systems

    NASA Astrophysics Data System (ADS)

    Ishchenko, A. V.; Belov, M. D.; Khokhlov, K. O.; Tcherepanov, A. N.; Naronov, A. S.

    2016-09-01

    The results of simulation of equivalent circuit of transmission line of down hole telemetry system has been presented. The paper shows the possible solution of communication system by a power-line communication technique for downhole monitoring. On the base of simulation results of equivalent circuit of presented model of transmission line the binary frequency-shift keying (BFSK) method of information transmission is proposed. The simulation of the temperature changing and disturbance appearance has been made. The influence of them on the signal parameters are presented and discussed.

  6. Computer Simulation Performed for Columbia Project Cooling System

    NASA Technical Reports Server (NTRS)

    Ahmad, Jasim

    2005-01-01

    This demo shows a high-fidelity simulation of the air flow in the main computer room housing the Columbia (10,024 intel titanium processors) system. The simulation asseses the performance of the cooling system and identified deficiencies, and recommended modifications to eliminate them. It used two in house software packages on NAS supercomputers: Chimera Grid tools to generate a geometric model of the computer room, OVERFLOW-2 code for fluid and thermal simulation. This state-of-the-art technology can be easily extended to provide a general capability for air flow analyses on any modern computer room. Columbia_CFD_black.tiff

  7. Development of a persistent chemical agent simulation system

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A Persistent Chemical Agent Simulation System was developed (PCASS) to simulate, for force-on-force training exercises, the field environment produced by the presence of persistent chemical agents. Such a simulant system must satisfy several requirements to be of value as a training aid. Specifically, it must provide for realistic training which will generate competency in at least the following areas: (1) detection of the persistent agent presence; (2) proper use of protective equipment and procedures; (3) determination of the extent of contamination; and (4) decontamination of equipment and personnel.

  8. A novel simulator for mechanical ventilation in newborns: MEchatronic REspiratory System SImulator for Neonatal Applications.

    PubMed

    Baldoli, Ilaria; Cuttano, Armando; Scaramuzzo, Rosa T; Tognarelli, Selene; Ciantelli, Massimiliano; Cecchi, Francesca; Gentile, Marzia; Sigali, Emilio; Laschi, Cecilia; Ghirri, Paolo; Menciassi, Arianna; Dario, Paolo; Boldrini, Antonio

    2015-08-01

    Respiratory problems are among the main causes of mortality for preterm newborns with pulmonary diseases; mechanical ventilation provides standard care, but long-term complications are still largely reported. In this framework, continuous medical education is mandatory to correctly manage assistance devices. However, commercially available neonatal respiratory simulators are rarely suitable for representing anatomical and physiological conditions; a step toward high-fidelity simulation, therefore, is essential for nurses and neonatologists to acquire the practice needed without any risk. An innovative multi-compartmental infant respirator simulator based on a five-lobe model was developed to reproduce different physio-pathological conditions in infants and to simulate many different kinds of clinical scenarios. The work consisted of three phases: (1) a theoretical study and modeling phase, (2) a prototyping phase, and (3) testing of the simulation software during training courses. The neonatal pulmonary simulator produced allows the replication and evaluation of different mechanical ventilation modalities in infants suffering from many different kinds of respiratory physio-pathological conditions. In particular, the system provides variable compliances for each lobe in an independent manner and different resistance levels for the airway branches; moreover, it allows the trainer to simulate both autonomous and mechanically assisted respiratory cycles in newborns. The developed and tested simulator is a significant contribution to the field of medical simulation in neonatology, as it makes it possible to choose the best ventilation strategy and to perform fully aware management of ventilation parameters. PMID:26238790

  9. Diversity modelling for electrical power system simulation

    NASA Astrophysics Data System (ADS)

    Sharip, R. M.; Abu Zarim, M. A. U. A.

    2013-12-01

    This paper considers diversity of generation and demand profiles against the different future energy scenarios and evaluates these on a technical basis. Compared to previous studies, this research applied a forecasting concept based on possible growth rates from publically electrical distribution scenarios concerning the UK. These scenarios were created by different bodies considering aspects such as environment, policy, regulation, economic and technical. In line with these scenarios, forecasting is on a long term timescale (up to every ten years from 2020 until 2050) in order to create a possible output of generation mix and demand profiles to be used as an appropriate boundary condition for the network simulation. The network considered is a segment of rural LV populated with a mixture of different housing types. The profiles for the 'future' energy and demand have been successfully modelled by applying a forecasting method. The network results under these profiles shows for the cases studied that even though the value of the power produced from each Micro-generation is often in line with the demand requirements of an individual dwelling there will be no problems arising from high penetration of Micro-generation and demand side management for each dwellings considered. The results obtained highlight the technical issues/changes for energy delivery and management to rural customers under the future energy scenarios.

  10. Implicit Kinetic simulations of multiple scale systems

    NASA Astrophysics Data System (ADS)

    Markidis, S.; Lapenta, G.; Zuccaro, G.; Tronci, C.

    2005-12-01

    As the community is acutely aware of, there is a need for new a tool capable to describe macroscopic processes while retaining sufficient detail about the microphysics. We propose a tool designed to handle cross-scale processes: CELESTE3D. CELESTE3D is based on fully kinetic ions and electrons and on a implicit formulation of both field solver and particle mover. The code was designed in the early 1990s and adhered to the most advanced software paradigms of the time. Furthermore the code had general geometry and grid adaptation, a feature key to cross-scale problems. However, the use of the code was limited to vector machines (as the CRAYS of those days and the Earth Simulator now). We report the next step in the development of CELESTE: PARSEK. PARSEK is based on the same algorithmic approach as CELESTE but it has a number of new features: 1) The particle mover and field solver are now relativistic; 2) The software infrastructure is completely new, based on a component-based software architecture using a object-oriented language; 3) All components are fully parallelized using MPI. We present the new code, its benchmark tests and some sample applications.

  11. Design and Simulation of MEMS Enabled Systems

    NASA Astrophysics Data System (ADS)

    da Silva, Mark

    2001-03-01

    Over the past two decades considerable progress in microsystems (MEMS) fabrication technologies has been made resulting in a variety of commercially successful devices. Most of these devices have required application specific fabrication steps, which must be developed, and the lack of proper design tools often resulted in repeated prototyping that was expensive and time consuming. Further development of MEMS enabled commercial products and reduction of the time to market requires implementation of a concurrent design methodology through better design tools and standardization of the fabrication processes. The cross-disciplinary nature of MEMS-Enabled Systems necessitates designers with different backgrounds to work together in understanding the effects of one sub-system on another and this requires a top-down approach to integrated system design. Design tools that can facilitate this communication and reduce the need for excessive prototype fabrication and test iterations and significantly reduce cost and time-to-market are vitally important. The main focus of this article is to describe the top-down design methodology and and ongoing research on tools that facilitate concurrent design of MEMS enabled systems.

  12. Simulation and simulator development of a separate surface attitude command control system for light aircraft

    NASA Technical Reports Server (NTRS)

    Roskam, J.

    1976-01-01

    A detailed description is presented of the simulation philosophy and process used in the development of a Separate Surface Attitude Command control system (SSAC) for a Beech Model 99 Airliner. The intent of this system is to provide complete three axes stability augmentation at low cost and without the need for system redundancy. The system, although aimed at the general aviation market, also has applications to certain military airplanes as well as to miniature submarines.

  13. Simulation research on ATP system of airborne laser communication

    NASA Astrophysics Data System (ADS)

    Zhao, Zhongyi; Huang, Hailong

    2015-02-01

    The compound axis tracking control circuits model of the ATP system was established and simulation was run on the tracking control performance of the ATP system. It was found through simulation that with the fixed coarse tracking error, the dynamic lag error in the coarse tracking servo system could be suppressed to 120μrad and with the fixed fine tracking error, the dynamic lag error in the fine tracking servo system could be restrained to 2.73μrad, and the vibration residual could be controlled within 1.5μrad.

  14. Strain System for the Motion Base Shuttle Mission Simulator

    NASA Technical Reports Server (NTRS)

    Huber, David C.; Van Vossen, Karl G.; Kunkel, Glenn W.; Wells, Larry W.

    2010-01-01

    The Motion Base Shuttle Mission Simulator (MBSMS) Strain System is an innovative engineering tool used to monitor the stresses applied to the MBSMS motion platform tilt pivot frames during motion simulations in real time. The Strain System comprises hardware and software produced by several different companies. The system utilizes a series of strain gages, accelerometers, orientation sensor, rotational meter, scanners, computer, and software packages working in unison. By monitoring and recording the inputs applied to the simulator, data can be analyzed if weld cracks or other problems are found during routine simulator inspections. This will help engineers diagnose problems as well as aid in repair solutions for both current as well as potential problems.

  15. Parallel Computing Environments and Methods for Power Distribution System Simulation

    SciTech Connect

    Lu, Ning; Taylor, Zachary T.; Chassin, David P.; Guttromson, Ross T.; Studham, Scott S.

    2005-11-10

    The development of cost-effective high-performance parallel computing on multi-processor super computers makes it attractive to port excessively time consuming simulation software from personal computers (PC) to super computes. The power distribution system simulator (PDSS) takes a bottom-up approach and simulates load at appliance level, where detailed thermal models for appliances are used. This approach works well for a small power distribution system consisting of a few thousand appliances. When the number of appliances increases, the simulation uses up the PC memory and its run time increases to a point where the approach is no longer feasible to model a practical large power distribution system. This paper presents an effort made to port a PC-based power distribution system simulator (PDSS) to a 128-processor shared-memory super computer. The paper offers an overview of the parallel computing environment and a description of the modification made to the PDSS model. The performances of the PDSS running on a standalone PC and on the super computer are compared. Future research direction of utilizing parallel computing in the power distribution system simulation is also addressed.

  16. A framework of modeling detector systems for computed tomography simulations

    NASA Astrophysics Data System (ADS)

    Youn, H.; Kim, D.; Kim, S. H.; Kam, S.; Jeon, H.; Nam, J.; Kim, H. K.

    2016-01-01

    Ultimate development in computed tomography (CT) technology may be a system that can provide images with excellent lesion conspicuity with the patient dose as low as possible. Imaging simulation tools have been cost-effectively used for these developments and will continue. For a more accurate and realistic imaging simulation, the signal and noise propagation through a CT detector system has been modeled in this study using the cascaded linear-systems theory. The simulation results are validated in comparisons with the measured results using a laboratory flat-panel micro-CT system. Although the image noise obtained from the simulations at higher exposures is slightly smaller than that obtained from the measurements, the difference between them is reasonably acceptable. According to the simulation results for various exposure levels and additive electronic noise levels, x-ray quantum noise is more dominant than the additive electronic noise. The framework of modeling a CT detector system suggested in this study will be helpful for the development of an accurate and realistic projection simulation model.

  17. RAM simulation model for SPH/RSV systems

    SciTech Connect

    Schryver, J.C.; Primm, A.H.; Nelson, S.C.

    1995-12-31

    The US Army`s Project Manager, Crusader is sponsoring the development of technologies that apply to the Self-Propelled Howitzer (SPH), formerly the Advanced Field Artillery System (AFAS), and Resupply Vehicle (RSV), formerly the Future Armored Resupply Vehicle (FARV), weapon system. Oak Ridge National Laboratory (ORNL) is currently performing developmental work in support of the SPH/PSV Crusader system. Supportive analyses of reliability, availability, and maintainability (RAM) aspects were also performed for the SPH/RSV effort. During FY 1994 and FY 1995 OPNL conducted a feasibility study to demonstrate the application of simulation modeling for RAM analysis of the Crusader system. Following completion of the feasibility study, a full-scale RAM simulation model of the Crusader system was developed for both the SPH and PSV. This report provides documentation for the simulation model as well as instructions in the proper execution and utilization of the model for the conduct of RAM analyses.

  18. Numerical simulation of magmatic hydrothermal systems

    USGS Publications Warehouse

    Ingebritsen, S.E.; Geiger, S.; Hurwitz, S.; Driesner, T.

    2010-01-01

    The dynamic behavior of magmatic hydrothermal systems entails coupled and nonlinear multiphase flow, heat and solute transport, and deformation in highly heterogeneous media. Thus, quantitative analysis of these systems depends mainly on numerical solution of coupled partial differential equations and complementary equations of state (EOS). The past 2 decades have seen steady growth of computational power and the development of numerical models that have eliminated or minimized the need for various simplifying assumptions. Considerable heuristic insight has been gained from process-oriented numerical modeling. Recent modeling efforts employing relatively complete EOS and accurate transport calculations have revealed dynamic behavior that was damped by linearized, less accurate models, including fluid property control of hydrothermal plume temperatures and three-dimensional geometries. Other recent modeling results have further elucidated the controlling role of permeability structure and revealed the potential for significant hydrothermally driven deformation. Key areas for future reSearch include incorporation of accurate EOS for the complete H2O-NaCl-CO2 system, more realistic treatment of material heterogeneity in space and time, realistic description of large-scale relative permeability behavior, and intercode benchmarking comparisons. Copyright 2010 by the American Geophysical Union.

  19. Simulator of IRST system with ATR embedded functions

    NASA Astrophysics Data System (ADS)

    Sozzi, B.; Fossati, E.; Barani, G.; Santini, N.; Ondini, A.; Colombi, G.; Quaranta, C.

    2010-04-01

    This paper presents a soft-real time simulator for IRST (InfraRed Search and Track) systems with ATR (Automatic Target Recognition) embedded functions to test airborne applications performance. The IR camera model includes detector, optics, available Field-of-Regard, etc., and it is integrated with the motion platform local stabilization system to consider all factors impacting IR images. The atmosphere contributions are taken into account by means of a link to ModTran computer program. Sensor simulation allows derivation and assessment of IR Figures of Merit (NEI, NETD, SNR...). IR signatures of targets derive both from data collected in specific trial campaigns and from laboratory built models. The simulation of the scan procedure takes into account different policies (ground points paths or defined angular volume) and different platform motion strategies (continuous or step steering scan). The scan process includes Kalman technique to face unexpected variations of aircraft motion. Track and ATR processors are simulated and run consistently on the output of the sensor model. The simulator functions are developed in MatLab and SIMULINK and then exported in C code to be integrated in soft real-time environment. The use of this simulator supports the definition and design of the IRST systems especially for the evaluation of the most demanding operative requirements. An application of this simulator is for the NEURON UCAV (Unmanned Combat Air Vehicle) technological demonstrator, which accommodates on board both IRST and ATR tasks.

  20. Synthetic Vision Systems - Operational Considerations Simulation Experiment

    NASA Technical Reports Server (NTRS)

    Kramer, Lynda J.; Williams, Steven P.; Bailey, Randall E.; Glaab, Louis J.

    2007-01-01

    Synthetic vision is a computer-generated image of the external scene topography that is generated from aircraft attitude, high-precision navigation information, and data of the terrain, obstacles, cultural features, and other required flight information. A synthetic vision system (SVS) enhances this basic functionality with real-time integrity to ensure the validity of the databases, perform obstacle detection and independent navigation accuracy verification, and provide traffic surveillance. Over the last five years, NASA and its industry partners have developed and deployed SVS technologies for commercial, business, and general aviation aircraft which have been shown to provide significant improvements in terrain awareness and reductions in the potential for Controlled-Flight-Into-Terrain incidents/accidents compared to current generation cockpit technologies. It has been hypothesized that SVS displays can greatly improve the safety and operational flexibility of flight in Instrument Meteorological Conditions (IMC) to a level comparable to clear-day Visual Meteorological Conditions (VMC), regardless of actual weather conditions or time of day. An experiment was conducted to evaluate SVS and SVS-related technologies as well as the influence of where the information is provided to the pilot (e.g., on a Head-Up or Head-Down Display) for consideration in defining landing minima based upon aircraft and airport equipage. The "operational considerations" evaluated under this effort included reduced visibility, decision altitudes, and airport equipage requirements, such as approach lighting systems, for SVS-equipped aircraft. Subjective results from the present study suggest that synthetic vision imagery on both head-up and head-down displays may offer benefits in situation awareness; workload; and approach and landing performance in the visibility levels, approach lighting systems, and decision altitudes tested.

  1. Synthetic vision systems: operational considerations simulation experiment

    NASA Astrophysics Data System (ADS)

    Kramer, Lynda J.; Williams, Steven P.; Bailey, Randall E.; Glaab, Louis J.

    2007-04-01

    Synthetic vision is a computer-generated image of the external scene topography that is generated from aircraft attitude, high-precision navigation information, and data of the terrain, obstacles, cultural features, and other required flight information. A synthetic vision system (SVS) enhances this basic functionality with real-time integrity to ensure the validity of the databases, perform obstacle detection and independent navigation accuracy verification, and provide traffic surveillance. Over the last five years, NASA and its industry partners have developed and deployed SVS technologies for commercial, business, and general aviation aircraft which have been shown to provide significant improvements in terrain awareness and reductions in the potential for Controlled-Flight-Into-Terrain incidents / accidents compared to current generation cockpit technologies. It has been hypothesized that SVS displays can greatly improve the safety and operational flexibility of flight in Instrument Meteorological Conditions (IMC) to a level comparable to clear-day Visual Meteorological Conditions (VMC), regardless of actual weather conditions or time of day. An experiment was conducted to evaluate SVS and SVS-related technologies as well as the influence of where the information is provided to the pilot (e.g., on a Head-Up or Head-Down Display) for consideration in defining landing minima based upon aircraft and airport equipage. The "operational considerations" evaluated under this effort included reduced visibility, decision altitudes, and airport equipage requirements, such as approach lighting systems, for SVS-equipped aircraft. Subjective results from the present study suggest that synthetic vision imagery on both head-up and head-down displays may offer benefits in situation awareness; workload; and approach and landing performance in the visibility levels, approach lighting systems, and decision altitudes tested.

  2. Whole body measurement systems. [for weightlessness simulation

    NASA Technical Reports Server (NTRS)

    Ogle, J. S. (Inventor)

    1973-01-01

    A system for measuring the volume and volume variations of a human body under zero gravity conditions is disclosed. An enclosed chamber having a defined volume and arranged for receiving a human body is provided with means for infrasonically varying the volume of the chamber. The changes in volume produce resultant changes in pressure, and under substantially isentropic conditions, an isentropic relationship permits a determination of gas volume which, in turn, when related to total chamber volume permits a determination of the body volume. By comparison techniques, volume changes of a human independent of gravity conditions can be determined.

  3. Advanced manned space flight simulation and training: An investigation of simulation host computer system concepts

    NASA Technical Reports Server (NTRS)

    Montag, Bruce C.; Bishop, Alfred M.; Redfield, Joe B.

    1989-01-01

    The findings of a preliminary investigation by Southwest Research Institute (SwRI) in simulation host computer concepts is presented. It is designed to aid NASA in evaluating simulation technologies for use in spaceflight training. The focus of the investigation is on the next generation of space simulation systems that will be utilized in training personnel for Space Station Freedom operations. SwRI concludes that NASA should pursue a distributed simulation host computer system architecture for the Space Station Training Facility (SSTF) rather than a centralized mainframe based arrangement. A distributed system offers many advantages and is seen by SwRI as the only architecture that will allow NASA to achieve established functional goals and operational objectives over the life of the Space Station Freedom program. Several distributed, parallel computing systems are available today that offer real-time capabilities for time critical, man-in-the-loop simulation. These systems are flexible in terms of connectivity and configurability, and are easily scaled to meet increasing demands for more computing power.

  4. High Level Architecture Distributed Space System Simulation for Simulation Interoperability Standards Organization Simulation Smackdown

    NASA Technical Reports Server (NTRS)

    Li, Zuqun

    2011-01-01

    Modeling and Simulation plays a very important role in mission design. It not only reduces design cost, but also prepares astronauts for their mission tasks. The SISO Smackdown is a simulation event that facilitates modeling and simulation in academia. The scenario of this year s Smackdown was to simulate a lunar base supply mission. The mission objective was to transfer Earth supply cargo to a lunar base supply depot and retrieve He-3 to take back to Earth. Federates for this scenario include the environment federate, Earth-Moon transfer vehicle, lunar shuttle, lunar rover, supply depot, mobile ISRU plant, exploratory hopper, and communication satellite. These federates were built by teams from all around the world, including teams from MIT, JSC, University of Alabama in Huntsville, University of Bordeaux from France, and University of Genoa from Italy. This paper focuses on the lunar shuttle federate, which was programmed by the USRP intern team from NASA JSC. The shuttle was responsible for provide transportation between lunar orbit and the lunar surface. The lunar shuttle federate was built using the NASA standard simulation package called Trick, and it was extended with HLA functions using TrickHLA. HLA functions of the lunar shuttle federate include sending and receiving interaction, publishing and subscribing attributes, and packing and unpacking fixed record data. The dynamics model of the lunar shuttle was modeled with three degrees of freedom, and the state propagation was obeying the law of two body dynamics. The descending trajectory of the lunar shuttle was designed by first defining a unique descending orbit in 2D space, and then defining a unique orbit in 3D space with the assumption of a non-rotating moon. Finally this assumption was taken away to define the initial position of the lunar shuttle so that it will start descending a second after it joins the execution. VPN software from SonicWall was used to connect federates with RTI during testing

  5. System and Method for Finite Element Simulation of Helicopter Turbulence

    NASA Technical Reports Server (NTRS)

    McFarland, R. E. (Inventor); Dulsenberg, Ken (Inventor)

    1999-01-01

    The present invention provides a turbulence model that has been developed for blade-element helicopter simulation. This model uses an innovative temporal and geometrical distribution algorithm that preserves the statistical characteristics of the turbulence spectra over the rotor disc, while providing velocity components in real time to each of five blade-element stations along each of four blades. for a total of twenty blade-element stations. The simulator system includes a software implementation of flight dynamics that adheres to the guidelines for turbulence set forth in military specifications. One of the features of the present simulator system is that it applies simulated turbulence to the rotor blades of the helicopter, rather than to its center of gravity. The simulator system accurately models the rotor penetration into a gust field. It includes time correlation between the front and rear of the main rotor, as well as between the side forces felt at the center of gravity and at the tail rotor. It also includes features for added realism, such as patchy turbulence and vertical gusts in to which the rotor disc penetrates. These features are realized by a unique real time implementation of the turbulence filters. The new simulator system uses two arrays one on either side of the main rotor to record the turbulence field and to produce time-correlation from the front to the rear of the rotor disc. The use of Gaussian Interpolation between the two arrays maintains the statistical properties of the turbulence across the rotor disc. The present simulator system and method may be used in future and existing real-time helicopter simulations with minimal increase in computational workload.

  6. Virtual global positioning system for distributed interactive simulation environments

    NASA Astrophysics Data System (ADS)

    Williams, Gary; Stytz, Martin R.; Banks, Sheila B.

    1997-07-01

    A major shortfall in the fidelity of current military distributed virtual environments (DVEs) is the lack of virtual global positioning system (GPS) timing and position signals for entities within the environment. The DVE's usefulness is reduced because positional errors and positional accuracy that would be available in the real world are not present in the DVE. This, in turn, affects the validity of the results of training, analysis, and evaluations involving systems that rely on GPS. The magnitude of the affect depends on the degree that the systems involved in the DVE rely on GPS in the real world. The project reported in this paper addresses this deficit in current military DVEs. The capability we developed to provide a virtual GPS-based navigation capability within a DVE is based upon three components. These components are a complete virtual GPS satellite constellation, a means for broadcasting GPS signals using the Distributed Interactive Simulation (DIS) simulation protocols, and a software system, the Virtual GPS Receiver (VGPSR), to calculate simulation entity position using the virtual GPS time and position signals. The virtual GPS satellites are propagated in their orbits using the solar system modeler (SM). The SM also performs the simulated GPS signal broadcast by transmitting a DIS protocol data unit (PDU) with the data that would appear within a real world GPS satellite broadcast. The VGPSR is a plug-in module available for simulation applications that require virtual GPS navigation. To demonstrate the capability of this system, we used the VGPSR in conjunction with the virtual cockpit to simulate virtual weapons deployment. We present the design of the VGPSR and the design of the modules added to the SM for GPS broadcast. We describe the calculations the system performs to calculate position in the virtual environment and we describe the accuracy and performance the system achieves when calculating virtual environment position using our system. We

  7. Numerical Propulsion System Simulation (NPSS) 1999 Industry Review

    NASA Technical Reports Server (NTRS)

    Lytle, John; Follen, Greg; Naiman, Cynthia; Evans, Austin

    2000-01-01

    The technologies necessary to enable detailed numerical simulations of complete propulsion systems are being developed at the NASA Glenn Research Center in cooperation with industry, academia, and other government agencies. Large scale, detailed simulations will be of great value to the nation because they eliminate some of the costly testing required to develop and certify advanced propulsion systems. In addition, time and cost savings will be achieved by enabling design details to be evaluated early in the development process before a commitment is made to a specific design. This concept is called the Numerical Propulsion System Simulation (NPSS). NPSS consists of three main elements: (1) engineering models that enable multidisciplinary analysis of large subsystems and systems at various levels of detail, (2) a simulation environment that maximizes designer productivity, and (3) a cost-effective, high-performance computing platform. A fundamental requirement of the concept is that the simulations must be capable of overnight execution on easily accessible computing platforms. This will greatly facilitate the use of large-scale simulations in a design environment. This paper describes the current status of the NPSS with specific emphasis on the progress made over the past year on air breathing propulsion applications. In addition, the paper contains a summary of the feedback received from industry partners in the development effort and the actions taken over the past year to respond to that feedback. The NPSS development was supported in FY99 by the High Performance Computing and Communications Program.

  8. Simulation laboratory for evaluating dynamic traffic management systems

    SciTech Connect

    Ban-Akiva, M.E.; Mishalani, R.G.; Yang, Q.; Koutsopoulos, H.N.

    1997-08-01

    This paper presents a simulation laboratory for performance evaluation and design refinement of dynamic traffic management systems. The laboratory consists of four integrated components: (1) a traffic management simulator, which mimics the generation of route guidance and operations of traffic signals and signs; (2) a traffic flow simulator, which models individual vehicle movements and drivers` route choice decisions in the presence of real-time traffic information; (3) a surveillance system module, which collects real-time traffic data from sensors and probe vehicles in the simulated network; and (4) a control device module, which implements control strategies and route guidance generated by the traffic management system under evaluation. The simulation laboratory has been implemented in C++ using object-oriented programming and a distributed environment. It features a graphical user interface that allows users to visualize the simulation process, including animation of vehicle movements, state of surveillance sensors, traffic signals, signs, and so on. This modeling system provides a unique tool for evaluating integrated ATIS and ATMS applications in a computer-based laboratory environment.

  9. Generalized simulation technique for turbojet engine system analysis

    NASA Technical Reports Server (NTRS)

    Seldner, K.; Mihaloew, J. R.; Blaha, R. J.

    1972-01-01

    A nonlinear analog simulation of a turbojet engine was developed. The purpose of the study was to establish simulation techniques applicable to propulsion system dynamics and controls research. A schematic model was derived from a physical description of a J85-13 turbojet engine. Basic conservation equations were applied to each component along with their individual performance characteristics to derive a mathematical representation. The simulation was mechanized on an analog computer. The simulation was verified in both steady-state and dynamic modes by comparing analytical results with experimental data obtained from tests performed at the Lewis Research Center with a J85-13 engine. In addition, comparison was also made with performance data obtained from the engine manufacturer. The comparisons established the validity of the simulation technique.

  10. Spatial Simulations in Systems Biology: From Molecules to Cells

    PubMed Central

    Klann, Michael; Koeppl, Heinz

    2012-01-01

    Cells are highly organized objects containing millions of molecules. Each biomolecule has a specific shape in order to interact with others in the complex machinery. Spatial dynamics emerge in this system on length and time scales which can not yet be modeled with full atomic detail. This review gives an overview of methods which can be used to simulate the complete cell at least with molecular detail, especially Brownian dynamics simulations. Such simulations require correct implementation of the diffusion-controlled reaction scheme occurring on this level. Implementations and applications of spatial simulations are presented, and finally it is discussed how the atomic level can be included for instance in multi-scale simulation methods. PMID:22837728

  11. Nexus: a modular workflow management system for quantum simulation codes

    DOE PAGES

    Krogel, Jaron T.

    2015-08-24

    The management of simulation workflows is a significant task for the individual computational researcher. Automation of the required tasks involved in simulation work can decrease the overall time to solution and reduce sources of human error. A new simulation workflow management system, Nexus, is presented to address these issues. Nexus is capable of automated job management on workstations and resources at several major supercomputing centers. Its modular design allows many quantum simulation codes to be supported within the same framework. Current support includes quantum Monte Carlo calculations with QMCPACK, density functional theory calculations with Quantum Espresso or VASP, and quantummore » chemical calculations with GAMESS. Users can compose workflows through a transparent, text-based interface, resembling the input file of a typical simulation code. A usage example is provided to illustrate the process.« less

  12. Nexus: a modular workflow management system for quantum simulation codes

    SciTech Connect

    Krogel, Jaron T.

    2015-08-24

    The management of simulation workflows is a significant task for the individual computational researcher. Automation of the required tasks involved in simulation work can decrease the overall time to solution and reduce sources of human error. A new simulation workflow management system, Nexus, is presented to address these issues. Nexus is capable of automated job management on workstations and resources at several major supercomputing centers. Its modular design allows many quantum simulation codes to be supported within the same framework. Current support includes quantum Monte Carlo calculations with QMCPACK, density functional theory calculations with Quantum Espresso or VASP, and quantum chemical calculations with GAMESS. Users can compose workflows through a transparent, text-based interface, resembling the input file of a typical simulation code. A usage example is provided to illustrate the process.

  13. Spatial simulations in systems biology: from molecules to cells.

    PubMed

    Klann, Michael; Koeppl, Heinz

    2012-01-01

    Cells are highly organized objects containing millions of molecules. Each biomolecule has a specific shape in order to interact with others in the complex machinery. Spatial dynamics emerge in this system on length and time scales which can not yet be modeled with full atomic detail. This review gives an overview of methods which can be used to simulate the complete cell at least with molecular detail, especially Brownian dynamics simulations. Such simulations require correct implementation of the diffusion-controlled reaction scheme occurring on this level. Implementations and applications of spatial simulations are presented, and finally it is discussed how the atomic level can be included for instance in multi-scale simulation methods. PMID:22837728

  14. Nexus: A modular workflow management system for quantum simulation codes

    NASA Astrophysics Data System (ADS)

    Krogel, Jaron T.

    2016-01-01

    The management of simulation workflows represents a significant task for the individual computational researcher. Automation of the required tasks involved in simulation work can decrease the overall time to solution and reduce sources of human error. A new simulation workflow management system, Nexus, is presented to address these issues. Nexus is capable of automated job management on workstations and resources at several major supercomputing centers. Its modular design allows many quantum simulation codes to be supported within the same framework. Current support includes quantum Monte Carlo calculations with QMCPACK, density functional theory calculations with Quantum Espresso or VASP, and quantum chemical calculations with GAMESS. Users can compose workflows through a transparent, text-based interface, resembling the input file of a typical simulation code. A usage example is provided to illustrate the process.

  15. Modelling and simulation of large solid state laser systems

    SciTech Connect

    Simmons, W.W.; Warren, W.E.

    1986-01-01

    The role of numerical methods to simulate the several physical processes (e.g., diffraction, self-focusing, gain saturation) that are involved in coherent beam propagation through large laser systems is discussed. A comprehensive simulation code for modeling the pertinent physical phenomena observed in laser operations (growth of small-scale modulation, spatial filter, imaging, gain saturation and beam-induced damage) is described in some detail. Comparisons between code results and solid state laser output performance data are presented. Design and performance estimation of the large Nova laser system at LLNL are given. Finally, a global design rule for large, solid state laser systems is discussed.

  16. Simulation and visualization of mechanical systems in immersive virtual environments

    SciTech Connect

    Canfield, T. R.

    1998-04-17

    A prototype for doing real-time simulation of mechanical systems in immersive virtual environments has been developed to run in the CAVE and on the ImmersaDesk at Argonne National Laboratory. This system has three principal software components: a visualization component for rendering the model and providing a user interface, communications software, and mechanics simulation software. The system can display the three-dimensional objects in the CAVE and project various scalar fields onto the exterior surface of the objects during real-time execution.

  17. Hybrid and electric advanced vehicle systems (heavy) simulation

    NASA Technical Reports Server (NTRS)

    Hammond, R. A.; Mcgehee, R. K.

    1981-01-01

    A computer program to simulate hybrid and electric advanced vehicle systems (HEAVY) is described. It is intended for use early in the design process: concept evaluation, alternative comparison, preliminary design, control and management strategy development, component sizing, and sensitivity studies. It allows the designer to quickly, conveniently, and economically predict the performance of a proposed drive train. The user defines the system to be simulated using a library of predefined component models that may be connected to represent a wide variety of propulsion systems. The development of three models are discussed as examples.

  18. Modeling and Simulation for Mission Operations Work System Design

    NASA Technical Reports Server (NTRS)

    Sierhuis, Maarten; Clancey, William J.; Seah, Chin; Trimble, Jay P.; Sims, Michael H.

    2003-01-01

    Work System analysis and design is complex and non-deterministic. In this paper we describe Brahms, a multiagent modeling and simulation environment for designing complex interactions in human-machine systems. Brahms was originally conceived as a business process design tool that simulates work practices, including social systems of work. We describe our modeling and simulation method for mission operations work systems design, based on a research case study in which we used Brahms to design mission operations for a proposed discovery mission to the Moon. We then describe the results of an actual method application project-the Brahms Mars Exploration Rover. Space mission operations are similar to operations of traditional organizations; we show that the application of Brahms for space mission operations design is relevant and transferable to other types of business processes in organizations.

  19. Star/horizon simulator used to test space guidance system

    NASA Technical Reports Server (NTRS)

    Schmidt, W. C.

    1967-01-01

    Star/horizon simulator is used for alignment and optical plus photoelectric tests of the sextant for the Apollo guidance and navigation system optical unit assembly. The unit is basically a refractive collimator with a two inch objective lens system and a twenty-four inch focal length.

  20. A prototype knowledge-based simulation support system

    SciTech Connect

    Hill, T.R.; Roberts, S.D.

    1987-04-01

    As a preliminary step toward the goal of an intelligent automated system for simulation modeling support, we explore the feasibility of the overall concept by generating and testing a prototypical framework. A prototype knowledge-based computer system was developed to support a senior level course in industrial engineering so that the overall feasibility of an expert simulation support system could be studied in a controlled and observable setting. The system behavior mimics the diagnostic (intelligent) process performed by the course instructor and teaching assistants, finding logical errors in INSIGHT simulation models and recommending appropriate corrective measures. The system was programmed in a non-procedural language (PROLOG) and designed to run interactively with students working on course homework and projects. The knowledge-based structure supports intelligent behavior, providing its users with access to an evolving accumulation of expert diagnostic knowledge. The non-procedural approach facilitates the maintenance of the system and helps merge the roles of expert and knowledge engineer by allowing new knowledge to be easily incorporated without regard to the existing flow of control. The background, features and design of the system are describe and preliminary results are reported. Initial success is judged to demonstrate the utility of the reported approach and support the ultimate goal of an intelligent modeling system which can support simulation modelers outside the classroom environment. Finally, future extensions are suggested.

  1. GROWTH OF HETROTROPHIC BIOFILMS IN A WATER DISTRIBUTION SYSTEM SIMULATOR

    EPA Science Inventory

    The U.S. EPA has designed and constructed a distribution system simulator (DSS) to evaluate factors which influence water quality within water distribution systems. Six individual 25 meter lengths of 15 cm diameter ductile iron pipe are arranged into loop configurations. Each lo...

  2. Airborne Electro-Optical Sensor Simulation System. Final Report.

    ERIC Educational Resources Information Center

    Hayworth, Don

    The total system capability, including all the special purpose and general purpose hardware comprising the Airborne Electro-Optical Sensor Simulation (AEOSS) System, is described. The functional relationship between hardware portions is described together with interface to the software portion of the computer image generation. Supporting rationale…

  3. Simulations Using a Computer/Videodisc System: Instructional Design Considerations.

    ERIC Educational Resources Information Center

    Ehrlich, Lisa R.

    Instructional design considerations involved in using level four videodisc systems when designing simulations are explored. Discussion of the hardware and software system characteristics notes that computer based training offers the features of text, graphics, color, animation, and highlighting techniques, while a videodisc player offers all of…

  4. A Special Education Systems Simulation Model: Teacher Training Emphasis.

    ERIC Educational Resources Information Center

    Jones, Wayne; And Others

    The authors illustrate the application of a systems approach for educational decision-makers through utilization of a special education systems simulation model with emphasis on teacher training. It is noted that the model provides a procedure to answer "what if" type questions before actually implementing a proposed program. Discussed are the…

  5. Designing Better Scaffolding in Teaching Complex Systems with Graphical Simulations

    ERIC Educational Resources Information Center

    Li, Na

    2013-01-01

    Complex systems are an important topic in science education today, but they are usually difficult for secondary-level students to learn. Although graphic simulations have many advantages in teaching complex systems, scaffolding is a critical factor for effective learning. This dissertation study was conducted around two complementary research…

  6. Development of an Intelligent Monitoring and Control System for a Heterogeneous Numerical Propulsion System Simulation

    NASA Technical Reports Server (NTRS)

    Reed, John A.; Afjeh, Abdollah A.; Lewandowski, Henry; Homer, Patrick T.; Schlichting, Richard D.

    1996-01-01

    The NASA Numerical Propulsion System Simulation (NPSS) project is exploring the use of computer simulation to facilitate the design of new jet engines. Several key issues raised in this research are being examined in an NPSS-related research project: zooming, monitoring and control, and support for heterogeneity. The design of a simulation executive that addresses each of these issues is described. In this work, the strategy of zooming, which allows codes that model at different levels of fidelity to be integrated within a single simulation, is applied to the fan component of a turbofan propulsion system. A prototype monitoring and control system has been designed for this simulation to support experimentation with expert system techniques for active control of the simulation. An interconnection system provides a transparent means of connecting the heterogeneous systems that comprise the prototype.

  7. Apollo experience report: Guidance and control systems. Engineering simulation program

    NASA Technical Reports Server (NTRS)

    Gilbert, D. W.

    1973-01-01

    The Apollo Program experience from early 1962 to July 1969 with respect to the engineering-simulation support and the problems encountered is summarized in this report. Engineering simulation in support of the Apollo guidance and control system is discussed in terms of design analysis and verification, certification of hardware in closed-loop operation, verification of hardware/software compatibility, and verification of both software and procedures for each mission. The magnitude, time, and cost of the engineering simulations are described with respect to hardware availability, NASA and contractor facilities (for verification of the command module, the lunar module, and the primary guidance, navigation, and control system), and scheduling and planning considerations. Recommendations are made regarding implementation of similar, large-scale simulations for future programs.

  8. [Activities of System Studies and Simulation, Inc.

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Contents include the following: 1. Launch Vehicle Interface Work Performed: a. S3 provided to KSC the new launch inclination targets needed for the April '04 launch date. 2. Prelaunch operations work performed: a. S3 updated the staffing plan for MSFC on-console personnel\\during the Final Countdown prior to launch. 3. Software Assessment Work Performed: a. S3 evaluated and recommended approval for Program Control Board (PCB) proposed change 649 for ground software changes, as well as change 650 and 650A for Stored Program Commands. 4. Education and Public Outreach Work Performed: a. S3 continues to coordinate the effort for the design and fabrication of scale models of the GP-3 for use at the launch site, education forums, and management/technical briefings. S3 also prepared a Change Request for additional funds needed for fabrication of additional scale models. S3 drafted the planned uses of these models, including the possibility of participation in the Boston, MA showings of the traveling Einstein Exhibit. 5. Program Management Support Work Performed: a. S3 prepared the input for and closed three MSFC Centerwide Action Item Tracking Systems (CAITS) actions during this period.

  9. A Distributed Simulation Software System for Multi-Spacecraft Missions

    NASA Technical Reports Server (NTRS)

    Burns, Richard; Davis, George; Cary, Everett

    2003-01-01

    The paper will provide an overview of the web-based distributed simulation software system developed for end-to-end, multi-spacecraft mission design, analysis, and test at the NASA Goddard Space Flight Center (GSFC). This software system was developed for an internal research and development (IR&D) activity at GSFC called the Distributed Space Systems (DSS) Distributed Synthesis Environment (DSE). The long-term goal of the DSS-DSE is to integrate existing GSFC stand-alone test beds, models, and simulation systems to create a "hands on", end-to-end simulation environment for mission design, trade studies and simulations. The short-term goal of the DSE was therefore to develop the system architecture, and then to prototype the core software simulation capability based on a distributed computing approach, with demonstrations of some key capabilities by the end of Fiscal Year 2002 (FY02). To achieve the DSS-DSE IR&D objective, the team adopted a reference model and mission upon which FY02 capabilities were developed. The software was prototyped according to the reference model, and demonstrations were conducted for the reference mission to validate interfaces, concepts, etc. The reference model, illustrated in Fig. 1, included both space and ground elements, with functional capabilities such as spacecraft dynamics and control, science data collection, space-to-space and space-to-ground communications, mission operations, science operations, and data processing, archival and distribution addressed.

  10. System Engineering Strategy for Distributed Multi-Purpose Simulation Architectures

    NASA Technical Reports Server (NTRS)

    Bhula, Dlilpkumar; Kurt, Cindy Marie; Luty, Roger

    2007-01-01

    This paper describes the system engineering approach used to develop distributed multi-purpose simulations. The multi-purpose simulation architecture focuses on user needs, operations, flexibility, cost and maintenance. This approach was used to develop an International Space Station (ISS) simulator, which is called the International Space Station Integrated Simulation (ISIS)1. The ISIS runs unmodified ISS flight software, system models, and the astronaut command and control interface in an open system design that allows for rapid integration of multiple ISS models. The initial intent of ISIS was to provide a distributed system that allows access to ISS flight software and models for the creation, test, and validation of crew and ground controller procedures. This capability reduces the cost and scheduling issues associated with utilizing standalone simulators in fixed locations, and facilitates discovering unknowns and errors earlier in the development lifecycle. Since its inception, the flexible architecture of the ISIS has allowed its purpose to evolve to include ground operator system and display training, flight software modification testing, and as a realistic test bed for Exploration automation technology research and development.

  11. High Frequency Mechanical Pyroshock Simulations for Payload Systems

    SciTech Connect

    BATEMAN,VESTA I.; BROWN,FREDERICK A.; CAP,JEROME S.; NUSSER,MICHAEL A.

    1999-12-15

    Sandia National Laboratories (SNL) designs mechanical systems with components that must survive high frequency shock environments including pyrotechnic shock. These environments have not been simulated very well in the past at the payload system level because of weight limitations of traditional pyroshock mechanical simulations using resonant beams and plates. A new concept utilizing tuned resonators attached to the payload system and driven with the impact of an airgun projectile allow these simulations to be performed in the laboratory with high precision and repeatability without the use of explosives. A tuned resonator has been designed and constructed for a particular payload system. Comparison of laboratory responses with measurements made at the component locations during actual pyrotechnic events show excellent agreement for a bandwidth of DC to 4 kHz. The bases of comparison are shock spectra. This simple concept applies the mechanical pyroshock simulation simultaneously to all components with the correct boundary conditions in the payload system and is a considerable improvement over previous experimental techniques and simulations.

  12. Final Technical Report "Multiscale Simulation Algorithms for Biochemical Systems"

    SciTech Connect

    Petzold, Linda R.

    2012-10-25

    Biochemical systems are inherently multiscale and stochastic. In microscopic systems formed by living cells, the small numbers of reactant molecules can result in dynamical behavior that is discrete and stochastic rather than continuous and deterministic. An analysis tool that respects these dynamical characteristics is the stochastic simulation algorithm (SSA, Gillespie, 1976), a numerical simulation procedure that is essentially exact for chemical systems that are spatially homogeneous or well stirred. Despite recent improvements, as a procedure that simulates every reaction event, the SSA is necessarily inefficient for most realistic problems. There are two main reasons for this, both arising from the multiscale nature of the underlying problem: (1) stiffness, i.e. the presence of multiple timescales, the fastest of which are stable; and (2) the need to include in the simulation both species that are present in relatively small quantities and should be modeled by a discrete stochastic process, and species that are present in larger quantities and are more efficiently modeled by a deterministic differential equation (or at some scale in between). This project has focused on the development of fast and adaptive algorithms, and the fun- damental theory upon which they must be based, for the multiscale simulation of biochemical systems. Areas addressed by this project include: (1) Theoretical and practical foundations for ac- celerated discrete stochastic simulation (tau-leaping); (2) Dealing with stiffness (fast reactions) in an efficient and well-justified manner in discrete stochastic simulation; (3) Development of adaptive multiscale algorithms for spatially homogeneous discrete stochastic simulation; (4) Development of high-performance SSA algorithms.

  13. Development of a multilayer interference simulation program for MSS systems

    NASA Technical Reports Server (NTRS)

    Izadian, Jamal S.

    1993-01-01

    This paper discusses the development of a multilayer interference analysis and simulation program which is used to evaluate interference between non-geostationary and geostationary satellites. In addition to evaluating interference, this program can be used in the development of sharing criteria and coordination among various Mobile Satellite Services (MSS) systems. A C++/Windows implementation of this program, called Globalstar Interference Simulation Program (GISP), has been developed.

  14. Web-Based Distributed Simulation of Aeronautical Propulsion System

    NASA Technical Reports Server (NTRS)

    Zheng, Desheng; Follen, Gregory J.; Pavlik, William R.; Kim, Chan M.; Liu, Xianyou; Blaser, Tammy M.; Lopez, Isaac

    2001-01-01

    An application was developed to allow users to run and view the Numerical Propulsion System Simulation (NPSS) engine simulations from web browsers. Simulations were performed on multiple INFORMATION POWER GRID (IPG) test beds. The Common Object Request Broker Architecture (CORBA) was used for brokering data exchange among machines and IPG/Globus for job scheduling and remote process invocation. Web server scripting was performed by JavaServer Pages (JSP). This application has proven to be an effective and efficient way to couple heterogeneous distributed components.

  15. A finite element simulation system in reservoir engineering

    SciTech Connect

    Gu, Xiaozhong

    1996-03-01

    Reservoir engineering is performed to predict the future performance of a reservoir based on its current state and past performance and to explore other methods for increasing the recovery of hydrocarbons from a reservoir. Reservoir simulations are routinely used for these purposes. A reservoir simulator is a sophisticated computer program which solves a system of partial differential equations describing multiphase fluid flow (oil, water, and gas) in a porous reservoir rock. This document describes the use of a reservoir simulator version of BOAST which was developed by the National Institute for Petroleum and Energy Research in July, 1991.

  16. The terminal area simulation system. Volume 2: Verification cases

    NASA Technical Reports Server (NTRS)

    Proctor, F. H.

    1987-01-01

    The numerical simulation of five case studies are presented and are compared with available data in order to verify the three-dimensional version of the Terminal Area Simulation System (TASS). A spectrum of convective storm types are selected for the case studies. Included are: a High-Plains supercell hailstorm, a small and relatively short-lived High-Plains cumulonimbus, a convective storm which produced the 2 August 1985 DFW microburst, a South Florida convective complex, and a tornadic Oklahoma thunderstorm. For each of the cases the model results compared reasonably well with observed data. In the simulations of the supercell storms many of their characteristic features were modeled, such as the hook echo, BWER, mesocyclone, gust fronts, giant persistent updraft, wall cloud, flanking-line towers, anvil and radar reflectivity overhang, and rightward veering in the storm propagation. In the simulation of the tornadic storm a horseshoe-shaped updraft configuration and cyclic changes in storm intensity and structure were noted. The simulation of the DFW microburst agreed remarkably well with sparse observed data. The simulated outflow rapidly expanded in a nearly symmetrical pattern and was associated with a ringvortex. A South Florida convective complex was simulated and contained updrafts and downdrafts in the form of discrete bubbles. The numerical simulations, in all cases, always remained stable and bounded with no anomalous trends.

  17. Prototype part task trainer: A remote manipulator system simulator

    NASA Technical Reports Server (NTRS)

    Shores, David

    1989-01-01

    The Part Task Trainer program (PTT) is a kinematic simulation of the Remote Manipulator System (RMS) for the orbiter. The purpose of the PTT is to supply a low cost man-in-the-loop simulator, allowing the student to learn operational procedures which then can be used in the more expensive full scale simulators. PTT will allow the crew members to work on their arm operation skills without the need for other people running the simulation. The controlling algorithms for the arm were coded out of the Functional Subsystem Requirements Document to ensure realistic operation of the simulation. Relying on the hardware of the workstation to provide fast refresh rates for full shaded images allows the simulation to be run on small low cost stand alone work stations, removing the need to be tied into a multi-million dollar computer for the simulation. PTT will allow the student to make errors which in full scale mock up simulators might cause failures or damage hardware. On the screen the user is shown a graphical representation of the RMS control panel in the aft cockpit of the orbiter, along with a main view window and up to six trunion and guide windows. The dials drawn on the panel may be turned to select the desired mode of operation. The inputs controlling the arm are read from a chair with a Translational Hand Controller (THC) and a Rotational Hand Controller (RHC) attached to it.

  18. Modeling and simulation role in designing a Teleradiology system.

    PubMed

    Alaoui, Adil; Vasilescu, Eugen; Lindisch, David; Subbiah, Nishant; Mun, Seong K

    2003-01-01

    In designing complex systems, Engineers, Developers and Systems Architects always have to make quantitative assumptions in order to satisfy anticipated loads and expectations of the final product. Many questions are asked before any complex system design that relate to systems performance, infrastructure and components configuration, behavior prediction and bottlenecks fixes. All these questions can be answered using modeling and simulation tools that allow engineers to predict systems behaviors in different settings and optimize systems in production by identifying bottlenecks and flaws in the infrastructure or workflow.

  19. Providing scalable system software for high-end simulations

    SciTech Connect

    Greenberg, D.

    1997-12-31

    Detailed, full-system, complex physics simulations have been shown to be feasible on systems containing thousands of processors. In order to manage these computer systems it has been necessary to create scalable system services. In this talk Sandia`s research on scalable systems will be described. The key concepts of low overhead data movement through portals and of flexible services through multi-partition architectures will be illustrated in detail. The talk will conclude with a discussion of how these techniques can be applied outside of the standard monolithic MPP system.

  20. Analysis of Aurora's Performance Simulation Engine for Three Systems

    SciTech Connect

    Freeman, Janine; Simon, Joseph

    2015-07-07

    Aurora Solar Inc. is building a cloud-based optimization platform to automate the design, engineering, and permit generation process of solar photovoltaic (PV) installations. They requested that the National Renewable Energy Laboratory (NREL) validate the performance of the PV system performance simulation engine of Aurora Solar’s solar design platform, Aurora. In previous work, NREL performed a validation of multiple other PV modeling tools 1, so this study builds upon that work by examining all of the same fixed-tilt systems with available module datasheets that NREL selected and used in the aforementioned study. Aurora Solar set up these three operating PV systems in their modeling platform using NREL-provided system specifications and concurrent weather data. NREL then verified the setup of these systems, ran the simulations, and compared the Aurora-predicted performance data to measured performance data for those three systems, as well as to performance data predicted by other PV modeling tools.

  1. Simulation of an interferometric computed tomography system for intraocular lenses

    NASA Astrophysics Data System (ADS)

    Tayag, Tristan J.; Bachim, Brent L.

    2010-08-01

    In this paper, we present a metrology system to characterize the refractive index profile of intraocular lenses (IOLs). Our system is based on interferometric optical phase computed tomography. We believe this metrology system to be a key enabling technology in the development of the next generation of IOLs. We propose a Fizeau-based optical configuration and present a simulation study on the application of computed tomography to IOL characterization.

  2. Solar Power Satellite antenna phase control system hardware simulation, phase 4. Volume 2: Analytical simulation of SPS system performance

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Kantak, A. V.; Chie, C. M.

    1981-01-01

    The pilot signal parameter optimization and power transponder analyses are presented. The SPS antenna phase control system is modeled and the hardware simulation study described. Ionospheric and system phase error effects and the effects of high power amplifier phase and amplitude jitters are considered. Parameter optimization of the spread spectrum receiver, consisting of the carrier tracking loop and the code tracking loop, is described.

  3. Parallel Signal Processing and System Simulation using aCe

    NASA Technical Reports Server (NTRS)

    Dorband, John E.; Aburdene, Maurice F.

    2003-01-01

    Recently, networked and cluster computation have become very popular for both signal processing and system simulation. A new language is ideally suited for parallel signal processing applications and system simulation since it allows the programmer to explicitly express the computations that can be performed concurrently. In addition, the new C based parallel language (ace C) for architecture-adaptive programming allows programmers to implement algorithms and system simulation applications on parallel architectures by providing them with the assurance that future parallel architectures will be able to run their applications with a minimum of modification. In this paper, we will focus on some fundamental features of ace C and present a signal processing application (FFT).

  4. Simulation of a Flywheel Electrical System for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Truong, Long V.; Wolff, Frederick J.; Dravid, Narayan V.

    2000-01-01

    A Flywheel Energy Storage Demonstration Project was initiated at the NASA Glenn Research Center as a possible replacement for the battery energy storage system on the International Space Station (ISS). While the hardware fabrication work was being performed at a university and contractor's facility, the related simulation activity was begun at Glenn. At the top level, Glenn researchers simulated the operation of the ISS primary electrical system (as described in another paper) with the Flywheel Energy Storage Unit (FESU) replacing one Battery Charge and Discharge Unit (BCDU). The FESU consists of a Permanent Magnet Synchronous Motor/Generator (PMSM), which is connected to the flywheel; the power electronics that connects the PMSM to the ISS direct-current bus; and the associated controller. The PMSM model is still under development, but this paper describes the rest of the FESU model-the simulation of the converter and the associated control system that regulates energy transfer to and from the flywheel.

  5. Development of a Persistent Chemical Agent Simulator System (PCASS)

    NASA Technical Reports Server (NTRS)

    Mcginness, W. G.

    1983-01-01

    The development of a persistent chemical agent simulation system (PCASS) is described. This PCASS is to be used for the military training of troops to simulate actual chemical warfare. The purpose of this system is to facilitate in the determination of chemical contamination and effectiveness of decontamination for training purposes. The fluorescent tracer employed has no daylight activation, but yet is easily removed with a decontaminate solution or water and surfactants. Also employed is a time delayed color developing system. When an individual is subjected to the PCASS and does not decontaminate adequately, red blotches or red coloration will develop as a function of time and temperature. The intent of this is to simulate the delayed chemical reaction of mustard contaminates.

  6. A Simulation Base Investigation of High Latency Space Systems Operations

    NASA Technical Reports Server (NTRS)

    Li, Zu Qun; Crues, Edwin Z.; Bielski, Paul; Moore, Michael

    2017-01-01

    NASA's human space program has developed considerable experience with near Earth space operations. Although NASA has experience with deep space robotic missions, NASA has little substantive experience with human deep space operations. Even in the Apollo program, the missions lasted only a few weeks and the communication latencies were on the order of seconds. Human missions beyond the relatively close confines of the Earth-Moon system will involve missions with durations measured in months and communications latencies measured in minutes. To minimize crew risk and to maximize mission success, NASA needs to develop a better understanding of the implications of these types of mission durations and communication latencies on vehicle design, mission design and flight controller interaction with the crew. To begin to address these needs, NASA performed a study using a physics-based subsystem simulation to investigate the interactions between spacecraft crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation, built with a subsystem modeling tool developed at NASA's Johnson Space Center, models the life support system of a Mars transit vehicle. The simulation contains models of the cabin atmosphere and pressure control system, electrical power system, drinking and waste water systems, internal and external thermal control systems, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the vehicle subsystems; 2) a mission control center interface with data transport delays up to 15 minutes each way; 3) a real-time simulation test conductor interface that can be use to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission between July 18th and Aug 3rd of year 2016. The NEEMO

  7. Economical graphics display system for flight simulation avionics

    NASA Technical Reports Server (NTRS)

    1990-01-01

    During the past academic year the focal point of this project has been to enhance the economical flight simulator system by incorporating it into the aero engineering educational environment. To accomplish this goal it was necessary to develop appropriate software modules that provide a foundation for student interaction with the system. In addition experiments had to be developed and tested to determine if they were appropriate for incorporation into the beginning flight simulation course, AERO-41B. For the most part these goals were accomplished. Experiments were developed and evaluated by graduate students. More work needs to be done in this area. The complexity and length of the experiments must be refined to match the programming experience of the target students. It was determined that few undergraduate students are ready to absorb the full extent and complexity of a real-time flight simulation. For this reason the experiments developed are designed to introduce basic computer architectures suitable for simulation, the programming environment and languages, the concept of math modules, evaluation of acquired data, and an introduction to the meaning of real-time. An overview is included of the system environment as it pertains to the students, an example of a flight simulation experiment performed by the students, and a summary of the executive programming modules created by the students to achieve a user-friendly multi-processor system suitable to an aero engineering educational program.

  8. Observing System Simulations for the GOLD and ICON Missions

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.

    2015-12-01

    We present results from a comprehensive observing simulation system for remote sensing observations by the Global-scale Observations of the Limb and Disk (GOLD) and Ionospheric Connection Explorer (ICON) missions. These NASA missions to explore the terrestrial thermosphere and ionosphere are planned for launch in 2017. The GOLD instrument is a far-ultraviolet spectrograph to be deployed on a commercial communications satellite at geostationary orbit. It will measure thermospheric temperature and composition during the day, and electron density at night, to understand the global effects of solar and geomagnetic events on the thermosphere-ionosphere system. ICON is an Explorer-class satellite to be launched into low-Earth orbit at 27 degrees inclination, and will measure thermosphere and ionosphere parameters with multiple remote-sensing and in-situ instruments, to discover the connections between lower atmosphere weather and changes in the low-latitude ionosphere. Instrument development, algorithm development, and ultimately data analysis, depend on a robust capability for simulating what we expect the instruments to observe. Therefore, we are constructing a flexible software system to serve both missions. The system uses simulations from general circulation models of the atmosphere-ionosphere system as input to an airglow model, performs spectral synthesis calculations, and applies observational parameters to predict what the instruments may observe from a generalized viewing geometry that can be applied to other space-based remote sensing measurements as well. In this presentation, we describe the system architecture and methodology, and present preliminary simulation results.

  9. Modeling and Simulation of an UAS Collision Avoidance Systems

    NASA Technical Reports Server (NTRS)

    Oliveros, Edgardo V.; Murray, A. Jennifer

    2010-01-01

    This paper describes a Modeling and Simulation of an Unmanned Aircraft Systems (UAS) Collision Avoidance System, capable of representing different types of scenarios for UAS collision avoidance. Commercial and military piloted aircraft currently utilize various systems for collision avoidance such as Traffic Alert and Collision A voidance System (TCAS), Automatic Dependent Surveillance-Broadcast (ADS-B), Radar and ElectroOptical and Infrared Sensors (EO-IR). The integration of information from these systems is done by the pilot in the aircraft to determine the best course of action. In order to operate optimally in the National Airspace System (NAS) UAS have to work in a similar or equivalent manner to a piloted aircraft by applying the principle of "detect-see and avoid" (DSA) to other air traffic. Hence, we have taken these existing sensor technologies into consideration in order to meet the challenge of researching the modeling and simulation of an approximated DSA system. A Schematic Model for a UAS Collision Avoidance System (CAS) has been developed ina closed loop block diagram for that purpose. We have found that the most suitable software to carry out this task is the Satellite Tool Kit (STK) from Analytical Graphics Inc. (AGI). We have used the Aircraft Mission Modeler (AMM) for modeling and simulation of a scenario where a UAS is placed on a possible collision path with an initial intruder and then with a second intruder, but is able to avoid them by executing a right tum maneuver and then climbing. Radars have also been modeled with specific characteristics for the UAS and both intruders. The software provides analytical, graphical user interfaces and data controlling tools which allow the operator to simulate different conditions. Extensive simulations have been carried out which returned excellent results.

  10. Simulation of the effectiveness evaluation process of security systems

    NASA Astrophysics Data System (ADS)

    Godovykh, A. V.; Stepanov, B. P.; Sheveleva, A. A.; Sharafieva, K. R.

    2016-06-01

    The paper is devoted to issues of creation of cross-functional analytical complex for simulation of the process of operation of the security system elements. Basic objectives, a design concept and an interrelation of main elements of the complex are described. The proposed conception of the analytical complex provides an opportunity to simulate processes for evaluating the effectiveness of physical protection system of a nuclear facility. The complex uses models, that take into account features of the object, parameters of technical means and tactics of adversaries. Recommendations were made for applying of this conception for training specialists in the field of physical protection of nuclear materials.

  11. A digital IF simulator for FM ranging systems

    NASA Astrophysics Data System (ADS)

    Bartlett, M. C.; Johnson, R. C.

    1980-03-01

    A digital intermediate frequency signal simulator (DIFSS) which is useful for testing many periodically modulated FM ranging systems is described. The DIFSS digitally computes the IF signal angle using angle tables stored in EPROM's and generates the cosine of the angle with a cosine PROM and D/A converter. Target delay time tau and doppler frequency can be varied as desired for static tests or dynamic target trajectories. The simulator is useful for testing real-time hardware or for testing ambiguous ranging system responses in a scaled-time mode.

  12. Simulation of Naval Guns' Breechblock System Dynamics Based on ADAMS

    NASA Astrophysics Data System (ADS)

    Tan, Bo; Liu, Hui-Min; Liu, Kai

    In order to study the dynamical characteristics of the breechblock system during gun firing, a virtual prototype model was established based on ADAMS, in which motion and force transmission among mechanisms are realized by collision. By simulation, kinematics and dynamics properties of main components are obtained, and the relationships between the motion of breechblock and the position of breechblock opening plate are analyzed. According to the simulation results, the collision among the breechblock opening plate and the roller is discontinuous, which may make the breechblock system fail to hitch the breechblock reliably. And within allowable scope of the structure, the breechblock opening template should be installed near the upside as much as possible.

  13. Effect of simulated weightlessness on the immune system in rats

    NASA Technical Reports Server (NTRS)

    Caren, L. D.; Mandel, A. D.; Nunes, J. A.

    1980-01-01

    Rats suspended in a model system designed to simulate many aspects of weightlessness were immunized with sheep red blood cells. Parameters measured on these and control rats included titers of anti-sheep red blood cell antibodies, serum immunoglobulin levels, spleen and thymus weights, hematocrits, and leukocyte differential counts on peripheral blood. No significant differences were found between test and weight-bearing, harnessed controls; however, the thymuses of animals in both these groups were significantly smaller than untreated cage controls. The lack of an effect of simulated weightlessness on the immune system is an interesting result, and its significance is discussed.

  14. NTP system simulation and detailed nuclear engine modeling

    NASA Technical Reports Server (NTRS)

    Anghaie, Samim

    1993-01-01

    The topics are presented in viewgraph form and include the following: nuclear thermal propulsion (NTP) & detailed nuclear engine modeling; modeling and engineering simulation of nuclear thermal rocket systems; nuclear thermal rocket simulation system; INSPI-NTVR core axial flow profiles; INSPI-NTRV core axial flow profiles; specific impulse vs. chamber pressure; turbine pressure ratio vs. chamber pressure; NERVA core axial flow profiles; P&W XNR2000 core axial flow profiles; pump pressure rise vs. chamber pressure; streamline of jet-induced flow in cylindrical chamber; flow pattern of a jet-induced flow in a chamber; and radiative heat transfer models.

  15. Alternative variable transformation for simulation of multibody dynamic systems

    NASA Astrophysics Data System (ADS)

    Yang, Li-Farn

    1995-03-01

    An alternative variable transformation is proposed and analyzed for the simulation of multibody dynamic systems. The developed alternative variable transformation matrix intended to work directly with the multibody equations of motion without altering the inherent dynamic characteristics also eliminates the need for expensive computation of inversion of a large mass matrix required for the simulation of multibody dynamic systems. From the analytical derivation of an articulated multibody model, it was found that the computation can be saved (3n + 1/4)-fold due to the computational merits associated with the band matrix.

  16. Testing of an Integrated Reactor Core Simulator and Power Conversion System with Simulated Reactivity Feedback

    NASA Technical Reports Server (NTRS)

    Bragg-Sitton, Shannon M.; Hervol, David S.; Godfroy, Thomas J.

    2010-01-01

    A Direct Drive Gas-Cooled (DDG) reactor core simulator has been coupled to a Brayton Power Conversion Unit (BPCU) for integrated system testing at NASA Glenn Research Center (GRC) in Cleveland, Ohio. This is a closed-cycle system that incorporates an electrically heated reactor core module, turboalternator, recuperator, and gas cooler. Nuclear fuel elements in the gas-cooled reactor design are replaced with electric resistance heaters to simulate the heat from nuclear fuel in the corresponding fast spectrum nuclear reactor. The thermodynamic transient behavior of the integrated system was the focus of this test series. In order to better mimic the integrated response of the nuclear-fueled system, a simulated reactivity feedback control loop was implemented. Core power was controlled by a point kinetics model in which the reactivity feedback was based on core temperature measurements; the neutron generation time and the temperature feedback coefficient are provided as model inputs. These dynamic system response tests demonstrate the overall capability of a non-nuclear test facility in assessing system integration issues and characterizing integrated system response times and response characteristics.

  17. Testing of an Integrated Reactor Core Simulator and Power Conversion System with Simulated Reactivity Feedback

    NASA Technical Reports Server (NTRS)

    Bragg-Sitton, Shannon M.; Hervol, David S.; Godfroy, Thomas J.

    2009-01-01

    A Direct Drive Gas-Cooled (DDG) reactor core simulator has been coupled to a Brayton Power Conversion Unit (BPCU) for integrated system testing at NASA Glenn Research Center (GRC) in Cleveland, OH. This is a closed-cycle system that incorporates an electrically heated reactor core module, turbo alternator, recuperator, and gas cooler. Nuclear fuel elements in the gas-cooled reactor design are replaced with electric resistance heaters to simulate the heat from nuclear fuel in the corresponding fast spectrum nuclear reactor. The thermodynamic transient behavior of the integrated system was the focus of this test series. In order to better mimic the integrated response of the nuclear-fueled system, a simulated reactivity feedback control loop was implemented. Core power was controlled by a point kinetics model in which the reactivity feedback was based on core temperature measurements; the neutron generation time and the temperature feedback coefficient are provided as model inputs. These dynamic system response tests demonstrate the overall capability of a non-nuclear test facility in assessing system integration issues and characterizing integrated system response times and response characteristics.

  18. The Communications link analysis and simulation system (CLASS)

    NASA Technical Reports Server (NTRS)

    Godfrey, R. D.

    1985-01-01

    The Communications Link Analysis and Simulation System (CLASS) is a comprehensive, computerized communications and tracking system analysis tool under development by the Networks Directorate of the NASA/GSFC. The primary use of this system is to provide the capability to predict the performance of the Tracking and Data Relay Satellite system (TDRSS) User Communications and Tracking links through the TDRSS. The general capabilities and operational philosophy of the current and final versions of the CLASS are described along with some examples of analyses which have been performed utilizing the capabilities of this system.

  19. Design of virtual SCADA simulation system for pressurized water reactor

    NASA Astrophysics Data System (ADS)

    Wijaksono, Umar; Abdullah, Ade Gafar; Hakim, Dadang Lukman

    2016-02-01

    The Virtual SCADA system is a software-based Human-Machine Interface that can visualize the process of a plant. This paper described the results of the virtual SCADA system design that aims to recognize the principle of the Nuclear Power Plant type Pressurized Water Reactor. This simulation uses technical data of the Nuclear Power Plant Unit Olkiluoto 3 in Finland. This device was developed using Wonderware Intouch, which is equipped with manual books for each component, animation links, alarm systems, real time and historical trending, and security system. The results showed that in general this device can demonstrate clearly the principles of energy flow and energy conversion processes in Pressurized Water Reactors. This virtual SCADA simulation system can be used as instructional media to recognize the principle of Pressurized Water Reactor.

  20. Effectively design and simulate thermosyphon reboiler systems. Part 1

    SciTech Connect

    Martin, G.R.; Sloley, A.W.

    1995-06-01

    Thermosyphon reboilers provide a simple, low-maintenance design for distillation tower reboiler systems. With an understanding of all the factors involved, thermosyphon designs should be more reliable than most other reboiler systems due to an absence of moving parts (pumps) in the process circulation loop. Design of true thermosyphon exchangers requires an intimate knowledge of a distillation tower`s heat balance, temperature levels and pressure balance in there boiler loop. Temperature levels vary strongly with composition gradients depending on the system relative volatilities. Case studies of two industrial units demonstrate implications on exchanger design of the correct and incorrect simulation configuration. The two cases compare a low relative-volatility {alpha} system (ethylene-ethane splitter) and a high {alpha} system (FCCU deethanizer). Main factors include impact on equipment size and design. Proper design criteria for thermosyphon exchanger and distillation tower simulation and for integrating process and equipment design are also shown.

  1. FEM simulation of TBC failure in a model system

    NASA Astrophysics Data System (ADS)

    Seiler, P.; Bäker, M.; Beck, T.; Schweda, M.; Rösier, J.

    2010-07-01

    In order to study the behavior of the complex failure mechanisms in thermal barrier coatings on turbine blades, a simplified model system is used to reduce the number of system parameters. The artificial system consists of a bond-coat material (fast creeping Fecralloy or slow creeping MA956) as the substrate with a Y2O3 partially stabilized plasma sprayed zircon oxide TBC on top and a TGO between the two layers. A 2-dimensional FEM simulation was developed to calculate the growth stress inside the simplified coating system. The simulation permits the study of failure mechanisms by identifying compression and tension areas which are established by the growth of the oxide layer. This provides an insight into the possible crack paths in the coating and it allows to draw conclusions for optimizing real thermal barrier coating systems.

  2. Simplified Simulation of Mass Transfer in Double White Dwarf Systems

    NASA Astrophysics Data System (ADS)

    Vannah, Sara; Frank, Juhan

    2016-01-01

    The behavior both stable and unstable mass transfer in semi-detached double white dwarfs triggers a cornucopia of astrophysical phenomena including Type Ia supernovae and AM CVn stars. Current 3D hydrodynamic simulations of the evolution these systems following the mass transfer, binary orbital parameters, and the self-consistent gravitational field over several tens of orbital periods have produced a wealth of data. However, these simulations can take weeks to months in high-performance computing platforms to execute. To help with the interpretation of results of such large scale simulations, and to enable a quick exploration of binary parameter space, we have developed a Mathematica code that integrates forward in time a system of 5 ODEs describing the orbit-averaged evolution of the binary separation as well as the radius, mass, and spin angular momentum of both components of the binary. By adjusting a few parameters describing the mass transfer as a function of the Roche-lobe overflow and the strength of the tidal coupling between the orbit and component spins we are able to obtain approximate fits to previously run hydrodynamic simulations. This simplified simulation is able to run simulations similar to the hydrodynamic versions in a matter of seconds on a dual-core PC or Mac computer.

  3. Hardware-in-the-loop tow missile system simulator

    SciTech Connect

    Waldman, G.S.; Wootton, J.R.; Hobson, G.L.; Holder, D.L.

    1993-07-06

    A missile system simulator is described for use in training people for target acquisition, missile launch, and missile guidance under simulated battlefield conditions comprising: simulating means for producing a digital signal representing a simulated battlefield environment including at least one target movable therewithin, the simulating means generating an infrared map representing the field-of-view and the target; interface means for converting said digital signals to an infrared image; missile system hardware including the missile acquisition, tracking, and guidance portions thereof, said hardware sensing the infrared image to determine the location of the target in a field-of-view; and, image means for generating an infrared image of a missile launched at the target and guided thereto, the image means imposing the missile image onto the field-of-view for the missile hardware to acquire the image of the missile in addition to that of the target, and to generate guidance signals to guide the missile image to the target image, wherein the interfacing means is responsive to a guidance signal from the hardware to simulate, in real-time, the response of the missile to the guidance signal, the image means including a blackbody, laser means for irradiating the blackbody to heat it to a temperature at which it emits infrared radiation, and optic means for integrating the radiant image produced by heating the blackbody into the infrared map.

  4. Explicit simulation of a midlatitude Mesoscale Convective System

    SciTech Connect

    Alexander, G.D.; Cotton, W.R.

    1996-04-01

    We have explicitly simulated the mesoscale convective system (MCS) observed on 23-24 June 1985 during PRE-STORM, the Preliminary Regional Experiment for the Stormscale Operational and Research and Meterology Program. Stensrud and Maddox (1988), Johnson and Bartels (1992), and Bernstein and Johnson (1994) are among the researchers who have investigated various aspects of this MCS event. We have performed this MCS simulation (and a similar one of a tropical MCS; Alexander and Cotton 1994) in the spirit of the Global Energy and Water Cycle Experiment Cloud Systems Study (GCSS), in which cloud-resolving models are used to assist in the formulation and testing of cloud parameterization schemes for larger-scale models. In this paper, we describe (1) the nature of our 23-24 June MCS dimulation and (2) our efforts to date in using our explicit MCS simulations to assist in the development of a GCM parameterization for mesoscale flow branches. The paper is organized as follows. First, we discuss the synoptic situation surrounding the 23-24 June PRE-STORM MCS followed by a discussion of the model setup and results of our simulation. We then discuss the use of our MCS simulation. We then discuss the use of our MCS simulations in developing a GCM parameterization for mesoscale flow branches and summarize our results.

  5. Biocellion: accelerating computer simulation of multicellular biological system models

    PubMed Central

    Kang, Seunghwa; Kahan, Simon; McDermott, Jason; Flann, Nicholas; Shmulevich, Ilya

    2014-01-01

    Motivation: Biological system behaviors are often the outcome of complex interactions among a large number of cells and their biotic and abiotic environment. Computational biologists attempt to understand, predict and manipulate biological system behavior through mathematical modeling and computer simulation. Discrete agent-based modeling (in combination with high-resolution grids to model the extracellular environment) is a popular approach for building biological system models. However, the computational complexity of this approach forces computational biologists to resort to coarser resolution approaches to simulate large biological systems. High-performance parallel computers have the potential to address the computing challenge, but writing efficient software for parallel computers is difficult and time-consuming. Results: We have developed Biocellion, a high-performance software framework, to solve this computing challenge using parallel computers. To support a wide range of multicellular biological system models, Biocellion asks users to provide their model specifics by filling the function body of pre-defined model routines. Using Biocellion, modelers without parallel computing expertise can efficiently exploit parallel computers with less effort than writing sequential programs from scratch. We simulate cell sorting, microbial patterning and a bacterial system in soil aggregate as case studies. Availability and implementation: Biocellion runs on x86 compatible systems with the 64 bit Linux operating system and is freely available for academic use. Visit http://biocellion.com for additional information. Contact: seunghwa.kang@pnnl.gov PMID:25064572

  6. Multispectral target simulation dome for hardware-in-the-loop simulation of fire control and optronic seeker systems

    NASA Astrophysics Data System (ADS)

    Muellner, Joseph

    2004-08-01

    The German MoD Research Establishment for Electronics and Communication Technology is currently implementing one of the world's largest advanced dome based Hardware-in-the-Loop simulation facility with high dynamics multispectral target representation. e.sigma Systems, Munich, is the prime contractor for the simulation systems and associated infrastructure. The facility will be used for research, development and validation of fire control and optronic seeker systems. The visual system for the target simulation contains a 40m dome with a special screen surface of 2200 sqm and a number of high resolution projection systems for the visual and IR spectrum. The simulation system also includes high dynamics, high precision motion simulators for the multispectral target projectors and the seeker systems under test. A high speed computer network for control, data acquisition and data recording links the subsystems at real time simulation rates of 1000Hz. The paper discusses the purpose of the simulation facility and its implementation.

  7. Simulation Of A Photofission-Based Cargo Interrogation System

    SciTech Connect

    King, Michael; Gozani, Tsahi; Stevenson, John; Shaw, Timothy

    2011-06-01

    A comprehensive model has been developed to characterize and optimize the detection of Bremsstrahlung x-ray induced fission signatures from nuclear materials hidden in cargo containers. An effective active interrogation system should not only induce a large number of fission events but also efficiently detect their signatures. The proposed scanning system utilizes a 9-MV commercially available linear accelerator and the detection of strong fission signals i.e. delayed gamma rays and prompt neutrons. Because the scanning system is complex and the cargo containers are large and often highly attenuating, the simulation method segments the model into several physical steps, representing each change of radiation particle. Each approximation is carried-out separately, resulting in a major reduction in computational time and a significant improvement in tally statistics. The model investigates the effect on the fission rate and detection rate by various cargo types, densities and distributions. Hydrogenous and metallic cargos, homogeneous and heterogeneous, as well as various locations of the nuclear material inside the cargo container were studied. We will show that for the photofission-based interrogation system simulation, the final results are not only in good agreement with a full, single-step simulation but also with experimental results, further validating the full-system simulation.

  8. Duality quantum algorithm efficiently simulates open quantum systems

    NASA Astrophysics Data System (ADS)

    Wei, Shi-Jie; Ruan, Dong; Long, Gui-Lu

    2016-07-01

    Because of inevitable coupling with the environment, nearly all practical quantum systems are open system, where the evolution is not necessarily unitary. In this paper, we propose a duality quantum algorithm for simulating Hamiltonian evolution of an open quantum system. In contrast to unitary evolution in a usual quantum computer, the evolution operator in a duality quantum computer is a linear combination of unitary operators. In this duality quantum algorithm, the time evolution of the open quantum system is realized by using Kraus operators which is naturally implemented in duality quantum computer. This duality quantum algorithm has two distinct advantages compared to existing quantum simulation algorithms with unitary evolution operations. Firstly, the query complexity of the algorithm is O(d3) in contrast to O(d4) in existing unitary simulation algorithm, where d is the dimension of the open quantum system. Secondly, By using a truncated Taylor series of the evolution operators, this duality quantum algorithm provides an exponential improvement in precision compared with previous unitary simulation algorithm.

  9. Duality quantum algorithm efficiently simulates open quantum systems.

    PubMed

    Wei, Shi-Jie; Ruan, Dong; Long, Gui-Lu

    2016-01-01

    Because of inevitable coupling with the environment, nearly all practical quantum systems are open system, where the evolution is not necessarily unitary. In this paper, we propose a duality quantum algorithm for simulating Hamiltonian evolution of an open quantum system. In contrast to unitary evolution in a usual quantum computer, the evolution operator in a duality quantum computer is a linear combination of unitary operators. In this duality quantum algorithm, the time evolution of the open quantum system is realized by using Kraus operators which is naturally implemented in duality quantum computer. This duality quantum algorithm has two distinct advantages compared to existing quantum simulation algorithms with unitary evolution operations. Firstly, the query complexity of the algorithm is O(d(3)) in contrast to O(d(4)) in existing unitary simulation algorithm, where d is the dimension of the open quantum system. Secondly, By using a truncated Taylor series of the evolution operators, this duality quantum algorithm provides an exponential improvement in precision compared with previous unitary simulation algorithm. PMID:27464855

  10. Duality quantum algorithm efficiently simulates open quantum systems.

    PubMed

    Wei, Shi-Jie; Ruan, Dong; Long, Gui-Lu

    2016-07-28

    Because of inevitable coupling with the environment, nearly all practical quantum systems are open system, where the evolution is not necessarily unitary. In this paper, we propose a duality quantum algorithm for simulating Hamiltonian evolution of an open quantum system. In contrast to unitary evolution in a usual quantum computer, the evolution operator in a duality quantum computer is a linear combination of unitary operators. In this duality quantum algorithm, the time evolution of the open quantum system is realized by using Kraus operators which is naturally implemented in duality quantum computer. This duality quantum algorithm has two distinct advantages compared to existing quantum simulation algorithms with unitary evolution operations. Firstly, the query complexity of the algorithm is O(d(3)) in contrast to O(d(4)) in existing unitary simulation algorithm, where d is the dimension of the open quantum system. Secondly, By using a truncated Taylor series of the evolution operators, this duality quantum algorithm provides an exponential improvement in precision compared with previous unitary simulation algorithm.

  11. Duality quantum algorithm efficiently simulates open quantum systems

    PubMed Central

    Wei, Shi-Jie; Ruan, Dong; Long, Gui-Lu

    2016-01-01

    Because of inevitable coupling with the environment, nearly all practical quantum systems are open system, where the evolution is not necessarily unitary. In this paper, we propose a duality quantum algorithm for simulating Hamiltonian evolution of an open quantum system. In contrast to unitary evolution in a usual quantum computer, the evolution operator in a duality quantum computer is a linear combination of unitary operators. In this duality quantum algorithm, the time evolution of the open quantum system is realized by using Kraus operators which is naturally implemented in duality quantum computer. This duality quantum algorithm has two distinct advantages compared to existing quantum simulation algorithms with unitary evolution operations. Firstly, the query complexity of the algorithm is O(d3) in contrast to O(d4) in existing unitary simulation algorithm, where d is the dimension of the open quantum system. Secondly, By using a truncated Taylor series of the evolution operators, this duality quantum algorithm provides an exponential improvement in precision compared with previous unitary simulation algorithm. PMID:27464855

  12. A Cryogenic Fluid System Simulation in Support of Integrated Systems Health Management

    NASA Technical Reports Server (NTRS)

    Barber, John P.; Johnston, Kyle B.; Daigle, Matthew

    2013-01-01

    Simulations serve as important tools throughout the design and operation of engineering systems. In the context of sys-tems health management, simulations serve many uses. For one, the underlying physical models can be used by model-based health management tools to develop diagnostic and prognostic models. These simulations should incorporate both nominal and faulty behavior with the ability to inject various faults into the system. Such simulations can there-fore be used for operator training, for both nominal and faulty situations, as well as for developing and prototyping health management algorithms. In this paper, we describe a methodology for building such simulations. We discuss the design decisions and tools used to build a simulation of a cryogenic fluid test bed, and how it serves as a core technology for systems health management development and maturation.

  13. Synchronous parallel system for emulation and discrete event simulation

    NASA Technical Reports Server (NTRS)

    Steinman, Jeffrey S. (Inventor)

    1992-01-01

    A synchronous parallel system for emulation and discrete event simulation having parallel nodes responds to received messages at each node by generating event objects having individual time stamps, stores only the changes to state variables of the simulation object attributable to the event object, and produces corresponding messages. The system refrains from transmitting the messages and changing the state variables while it determines whether the changes are superseded, and then stores the unchanged state variables in the event object for later restoral to the simulation object if called for. This determination preferably includes sensing the time stamp of each new event object and determining which new event object has the earliest time stamp as the local event horizon, determining the earliest local event horizon of the nodes as the global event horizon, and ignoring the events whose time stamps are less than the global event horizon. Host processing between the system and external terminals enables such a terminal to query, monitor, command or participate with a simulation object during the simulation process.

  14. The role of the research simulator in the systems development of rotorcraft

    NASA Technical Reports Server (NTRS)

    Statler, I. C.; Deel, A.

    1981-01-01

    The potential application of the research simulator to future rotorcraft systems design, development, product improvement evaluations, and safety analysis is examined. Current simulation capabilities for fixed-wing aircraft are reviewed and the requirements of a rotorcraft simulator are defined. The visual system components, vertical motion simulator, cab, and computation system for a research simulator under development are described.

  15. Algorithm for Simulating Atmospheric Turbulence and Aeroelastic Effects on Simulator Motion Systems

    NASA Technical Reports Server (NTRS)

    Ercole, Anthony V.; Cardullo, Frank M.; Kelly, Lon C.; Houck, Jacob A.

    2012-01-01

    Atmospheric turbulence produces high frequency accelerations in aircraft, typically greater than the response to pilot input. Motion system equipped flight simulators must present cues representative of the aircraft response to turbulence in order to maintain the integrity of the simulation. Currently, turbulence motion cueing produced by flight simulator motion systems has been less than satisfactory because the turbulence profiles have been attenuated by the motion cueing algorithms. This report presents a new turbulence motion cueing algorithm, referred to as the augmented turbulence channel. Like the previous turbulence algorithms, the output of the channel only augments the vertical degree of freedom of motion. This algorithm employs a parallel aircraft model and an optional high bandwidth cueing filter. Simulation of aeroelastic effects is also an area where frequency content must be preserved by the cueing algorithm. The current aeroelastic implementation uses a similar secondary channel that supplements the primary motion cue. Two studies were conducted using the NASA Langley Visual Motion Simulator and Cockpit Motion Facility to evaluate the effect of the turbulence channel and aeroelastic model on pilot control input. Results indicate that the pilot is better correlated with the aircraft response, when the augmented channel is in place.

  16. Investigations into Distribution System Nitrification: Simulated Systems and Microelectrode Biofilm Profiling

    EPA Science Inventory

    Results from USEPA research investigating drinking water distribution system nitrification will be presented. The two research areas include: (1) microbial community and reactor performance data from simulated drinking water distribution system using annular reactors and (2) mi...

  17. Tool Support for Parametric Analysis of Large Software Simulation Systems

    NASA Technical Reports Server (NTRS)

    Schumann, Johann; Gundy-Burlet, Karen; Pasareanu, Corina; Menzies, Tim; Barrett, Tony

    2008-01-01

    The analysis of large and complex parameterized software systems, e.g., systems simulation in aerospace, is very complicated and time-consuming due to the large parameter space, and the complex, highly coupled nonlinear nature of the different system components. Thus, such systems are generally validated only in regions local to anticipated operating points rather than through characterization of the entire feasible operational envelope of the system. We have addressed the factors deterring such an analysis with a tool to support envelope assessment: we utilize a combination of advanced Monte Carlo generation with n-factor combinatorial parameter variations to limit the number of cases, but still explore important interactions in the parameter space in a systematic fashion. Additional test-cases, automatically generated from models (e.g., UML, Simulink, Stateflow) improve the coverage. The distributed test runs of the software system produce vast amounts of data, making manual analysis impossible. Our tool automatically analyzes the generated data through a combination of unsupervised Bayesian clustering techniques (AutoBayes) and supervised learning of critical parameter ranges using the treatment learner TAR3. The tool has been developed around the Trick simulation environment, which is widely used within NASA. We will present this tool with a GN&C (Guidance, Navigation and Control) simulation of a small satellite system.

  18. Modeling and Fault Simulation of Propellant Filling System

    NASA Astrophysics Data System (ADS)

    Jiang, Yunchun; Liu, Weidong; Hou, Xiaobo

    2012-05-01

    Propellant filling system is one of the key ground plants in launching site of rocket that use liquid propellant. There is an urgent demand for ensuring and improving its reliability and safety, and there is no doubt that Failure Mode Effect Analysis (FMEA) is a good approach to meet it. Driven by the request to get more fault information for FMEA, and because of the high expense of propellant filling, in this paper, the working process of the propellant filling system in fault condition was studied by simulating based on AMESim. Firstly, based on analyzing its structure and function, the filling system was modular decomposed, and the mathematic models of every module were given, based on which the whole filling system was modeled in AMESim. Secondly, a general method of fault injecting into dynamic system was proposed, and as an example, two typical faults - leakage and blockage - were injected into the model of filling system, based on which one can get two fault models in AMESim. After that, fault simulation was processed and the dynamic characteristics of several key parameters were analyzed under fault conditions. The results show that the model can simulate effectively the two faults, and can be used to provide guidance for the filling system maintain and amelioration.

  19. Parareal in Time for Dynamic Simulations of Power Systems

    SciTech Connect

    Gurrala, Gurunath; Dimitrovski, Aleksandar D; Pannala, Sreekanth; Simunovic, Srdjan; Starke, Michael R

    2015-01-01

    In recent years, there have been significant developments in parallel algorithms and high performance parallel computing platforms. Parareal in time algorithm has become popular for long transient simulations (e.g., molecular dynamics, fusion, reacting flows). Parareal is a parallel algorithm which divides the time interval into sub-intervals and solves them concurrently. This paper investigates the applicability of the parareal algorithm to power system dynamic simulations. Preliminary results on the application of parareal for multi-machine power systems are reported in this paper. Two widely used test systems, WECC 3-generator 9-bus system, New England 10-generator 39- bus system, is used to explore the effectiveness of the parareal. Severe 3 phase bus faults are simulated using both the classical and detailed models of multi-machine power systems. Actual Speedup of 5-7 times is observed assuming ideal parallelization. It has been observed that the speedup factors of the order of 20 can be achieved by using fast coarse approximations of power system models. Dependency of parareal convergence on fault duration and location has been observed.

  20. GPSIM: A Personal Computer-Based GPS Simulator System

    NASA Astrophysics Data System (ADS)

    Ibrahim, D.

    Global Positioning Systems (GPS) are now in use in many applications, ranging from GIS to route guidance, automatic vehicle location (AVL), air, land, and marine navigation, and many other transportation and geographical based applications. In many applications, the GPS receiver is connected to some form of intelligent electronic system which receives the positional data from the GPS unit and then performs the required operation. When developing and testing GPS-based systems, one of the problems is that it is usually necessary to create GPS-compatible geographical data to simulate a GPS operation in real time. This paper provides the details of a Personal Computer (PC)-based GPS simulator system called GPSIM. The system receives user way-points and routes from Windows-based screen forms and then simulates a GPS operation in real time by generating most of the commonly used GPS sentences. The user-specified waypoints are divided into a number of small segments, each segment specifying a small distance in the direction of the original waypoint. The GPS sentence corresponding to the geographical coordinates of each segment is then sent out of the PC serial port. The system described is an invaluable testing tool for GPS-based system developers and also for people training to learn to use GPS-based products.

  1. ESTL tracking and data relay satellite /TDRSS/ simulation system

    NASA Technical Reports Server (NTRS)

    Kapell, M. H.

    1980-01-01

    The Tracking Data Relay Satellite System (TDRSS) provides single access forward and return communication links with the Shuttle/Orbiter via S-band and Ku-band frequency bands. The ESTL (Electronic Systems Test Laboratory) at Lyndon B. Johnson Space Center (JSC) utilizes a TDRS satellite simulator and critical TDRS ground hardware for test operations. To accomplish Orbiter/TDRSS relay communications performance testing in the ESTL, a satellite simulator was developed which met the specification requirements of the TDRSS channels utilized by the Orbiter. Actual TDRSS ground hardware unique to the Orbiter communication interfaces was procured from individual vendors, integrated in the ESTL, and interfaced via a data bus for control and status monitoring. This paper discusses the satellite simulation hardware in terms of early development and subsequent modifications. The TDRS ground hardware configuration and the complex computer interface requirements are reviewed. Also, special test hardware such as a radio frequency interference test generator is discussed.

  2. Modeling and simulation of biological systems from image data

    PubMed Central

    Sbalzarini, Ivo F

    2013-01-01

    This essay provides an introduction to the terminology, concepts, methods, and challenges of image-based modeling in biology. Image-based modeling and simulation aims at using systematic, quantitative image data to build predictive models of biological systems that can be simulated with a computer. This allows one to disentangle molecular mechanisms from effects of shape and geometry. Questions like “what is the functional role of shape” or “how are biological shapes generated and regulated” can be addressed in the framework of image-based systems biology. The combination of image quantification, model building, and computer simulation is illustrated here using the example of diffusion in the endoplasmic reticulum. PMID:23533152

  3. Simulated, Emulated, and Physical Investigative Analysis (SEPIA) of networked systems.

    SciTech Connect

    Burton, David P.; Van Leeuwen, Brian P.; McDonald, Michael James; Onunkwo, Uzoma A.; Tarman, Thomas David; Urias, Vincent E.

    2009-09-01

    This report describes recent progress made in developing and utilizing hybrid Simulated, Emulated, and Physical Investigative Analysis (SEPIA) environments. Many organizations require advanced tools to analyze their information system's security, reliability, and resilience against cyber attack. Today's security analysis utilize real systems such as computers, network routers and other network equipment, computer emulations (e.g., virtual machines) and simulation models separately to analyze interplay between threats and safeguards. In contrast, this work developed new methods to combine these three approaches to provide integrated hybrid SEPIA environments. Our SEPIA environments enable an analyst to rapidly configure hybrid environments to pass network traffic and perform, from the outside, like real networks. This provides higher fidelity representations of key network nodes while still leveraging the scalability and cost advantages of simulation tools. The result is to rapidly produce large yet relatively low-cost multi-fidelity SEPIA networks of computers and routers that let analysts quickly investigate threats and test protection approaches.

  4. A perspective on modeling and simulation of complex dynamical systems

    NASA Astrophysics Data System (ADS)

    Åström, K. J.

    2011-09-01

    There has been an amazing development of modeling and simulation from its beginning in the 1920s, when the technology was available only at a handful of University groups who had access to a mechanical differential analyzer. Today, tools for modeling and simulation are available for every student and engineer. This paper gives a perspective on the development with particular emphasis on technology and paradigm shifts. Modeling is increasingly important for design and operation of complex natural and man-made systems. Because of the increased use of model based control such as Kalman filters and model predictive control, models are also appearing as components of feedback systems. Modeling and simulation are multidisciplinary, it is used in a wide variety of fields and their development have been strongly influenced by mathematics, numerics, computer science and computer technology.

  5. A flexible system for the simulation of turbocharged diesel engines and turbocharging systems

    SciTech Connect

    Bulaty, T.; Codan, E.; Skopil, M.

    1996-12-31

    A fully flexible simulation system enables substitution of the conventional tests performed on turbocharged diesel engines. The supercharging systems can be calculated either by filling and emptying or by the differential method for 1-D unsteady flow during steady-state or transient operation. During sophisticated simulations, some conservation problems were observed. Their theoretical explanation and a practical solution are presented.

  6. Numeric Modified Adomian Decomposition Method for Power System Simulations

    SciTech Connect

    Dimitrovski, Aleksandar D; Simunovic, Srdjan; Pannala, Sreekanth

    2016-01-01

    This paper investigates the applicability of numeric Wazwaz El Sayed modified Adomian Decomposition Method (WES-ADM) for time domain simulation of power systems. WESADM is a numerical method based on a modified Adomian decomposition (ADM) technique. WES-ADM is a numerical approximation method for the solution of nonlinear ordinary differential equations. The non-linear terms in the differential equations are approximated using Adomian polynomials. In this paper WES-ADM is applied to time domain simulations of multimachine power systems. WECC 3-generator, 9-bus system and IEEE 10-generator, 39-bus system have been used to test the applicability of the approach. Several fault scenarios have been tested. It has been found that the proposed approach is faster than the trapezoidal method with comparable accuracy.

  7. Automatic computer-aided system of simulating solder joint formation

    NASA Astrophysics Data System (ADS)

    Zhao, Xiujuan; Wang, Chunqing; Zheng, Guanqun; Wang, Gouzhong; Yang, Shiqin

    1999-08-01

    One critical aspect in electronic packaging is the fatigue/creep-induced failure in solder interconnections, which is found to be highly dependent on the shape of solder joints. Thus predicting and analyzing the solder joint shape is warranted. In this paper, an automatic computer-aided system is developed to simulate the formation of solder joint and analyze the influence of the different process parameters on the solder joint shape. The developed system is capable of visually designing the process parameters and calculating the solder joint shape automatically without any intervention from the user. The automation achieved will enable fast shape estimation with the variation of process parameters without time consuming experiments, and the simulating system provides the design and manufacturing engineers an efficient software tools to design soldering process in design environment. Moreover, a program developed from the system can serve as the preprocessor for subsequent finite element joint analysis program.

  8. A review of numerical simulation of hydrothermal systems.

    USGS Publications Warehouse

    Mercer, J.W.; Faust, C.R.

    1979-01-01

    Many advances in simulating single and two-phase fluid flow and heat transport in porous media have recently been made in conjunction with geothermal energy research. These numerical models reproduce system thermal and pressure behaviour and can be used for other heat-transport problems, such as high-level radioactive waste disposal and heat-storage projects. -Authors

  9. Systems Approaches and Simulation in Curricular Programs: The Wageningen Experience.

    ERIC Educational Resources Information Center

    van Dam, A. M.; And Others

    1997-01-01

    Wageningen Agricultural University's use of systems approaches and simulation for undergraduate, graduate, and postgraduate education suggests the following elements are necessary: (1) congruence between the aims/interests of teachers and participants; (2) appropriate course level; (3) applicability to relevant research fields; and (4) a range of…

  10. SWAT Revisions for Simulating Landscape Components and Buffer systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods for simulating different landscape positions within the SWAT model are being examined. A three component system, consisting of the watershed divide, the hillslope, and the floodplain landscape positions, has been developed to address flow and transport across hydrologic response units prior...

  11. Communication Systems Simulator with Error Correcting Codes Using MATLAB

    ERIC Educational Resources Information Center

    Gomez, C.; Gonzalez, J. E.; Pardo, J. M.

    2003-01-01

    In this work, the characteristics of a simulator for channel coding techniques used in communication systems, are described. This software has been designed for engineering students in order to facilitate the understanding of how the error correcting codes work. To help students understand easily the concepts related to these kinds of codes, a…

  12. The 3-axis Dynamic Motion Simulator (DMS) system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A three-axis dynamic motion simulator (DMS) consisting of a test table with three degrees of freedom and an electronics control system was designed, constructed, delivered, and tested. Documentation, as required in the Data Requirements List (DRL), was also provided.

  13. Three-Dimensional Magnetohydrodynamic Simulation of Slapper Initiation Systems

    SciTech Connect

    Christensen, J S; Hrousis, C A

    2010-03-09

    Although useful information can be gleaned from 2D and even 1D simulations of slapper type initiation systems, these systems are inherently three-dimensional and therefore require full 3D representation to model all relevant details. Further, such representation provides additional insight into optimizing the design of such devices from a first-principles perspective and can thereby reduce experimental costs. We discuss in this paper several ongoing efforts in modeling these systems, our pursuit of validation, and extension of these methods to other systems. Our results show the substantial dependence upon highly accurate global equations of state and resistivity models in these analyses.

  14. IUS/payload communication system simulator configuration definition study. [payload simulator for pcm telemetry

    NASA Technical Reports Server (NTRS)

    Udalov, S.; Springett, J. C.

    1978-01-01

    The requirements and specifications for a general purpose payload communications system simulator to be used to emulate those communications system portions of NASA and DOD payloads/spacecraft that will in the future be carried into earth orbit by the shuttle are discussed. For the purpose of on-orbit checkout, the shuttle is required to communicate with the payloads while they are physically located within the shuttle bay (attached) and within a range of 20 miles from the shuttle after they have been deployed (detached). Many of the payloads are also under development (and many have yet to be defined), actual payload communication hardware will not be available within the time frame during which the avionic hardware tests will be conducted. Thus, a flexible payload communication system simulator is required.

  15. An Integrated Simulation Module for Cyber-Physical Automation Systems.

    PubMed

    Ferracuti, Francesco; Freddi, Alessandro; Monteriù, Andrea; Prist, Mariorosario

    2016-01-01

    The integration of Wireless Sensors Networks (WSNs) into Cyber Physical Systems (CPSs) is an important research problem to solve in order to increase the performances, safety, reliability and usability of wireless automation systems. Due to the complexity of real CPSs, emulators and simulators are often used to replace the real control devices and physical connections during the development stage. The most widespread simulators are free, open source, expandable, flexible and fully integrated into mathematical modeling tools; however, the connection at a physical level and the direct interaction with the real process via the WSN are only marginally tackled; moreover, the simulated wireless sensor motes are not able to generate the analogue output typically required for control purposes. A new simulation module for the control of a wireless cyber-physical system is proposed in this paper. The module integrates the COntiki OS JAva Simulator (COOJA), a cross-level wireless sensor network simulator, and the LabVIEW system design software from National Instruments. The proposed software module has been called "GILOO" (Graphical Integration of Labview and cOOja). It allows one to develop and to debug control strategies over the WSN both using virtual or real hardware modules, such as the National Instruments Real-Time Module platform, the CompactRio, the Supervisory Control And Data Acquisition (SCADA), etc. To test the proposed solution, we decided to integrate it with one of the most popular simulators, i.e., the Contiki OS, and wireless motes, i.e., the Sky mote. As a further contribution, the Contiki Sky DAC driver and a new "Advanced Sky GUI" have been proposed and tested in the COOJA Simulator in order to provide the possibility to develop control over the WSN. To test the performances of the proposed GILOO software module, several experimental tests have been made, and interesting preliminary results are reported. The GILOO module has been applied to a smart home

  16. An Integrated Simulation Module for Cyber-Physical Automation Systems.

    PubMed

    Ferracuti, Francesco; Freddi, Alessandro; Monteriù, Andrea; Prist, Mariorosario

    2016-05-05

    The integration of Wireless Sensors Networks (WSNs) into Cyber Physical Systems (CPSs) is an important research problem to solve in order to increase the performances, safety, reliability and usability of wireless automation systems. Due to the complexity of real CPSs, emulators and simulators are often used to replace the real control devices and physical connections during the development stage. The most widespread simulators are free, open source, expandable, flexible and fully integrated into mathematical modeling tools; however, the connection at a physical level and the direct interaction with the real process via the WSN are only marginally tackled; moreover, the simulated wireless sensor motes are not able to generate the analogue output typically required for control purposes. A new simulation module for the control of a wireless cyber-physical system is proposed in this paper. The module integrates the COntiki OS JAva Simulator (COOJA), a cross-level wireless sensor network simulator, and the LabVIEW system design software from National Instruments. The proposed software module has been called "GILOO" (Graphical Integration of Labview and cOOja). It allows one to develop and to debug control strategies over the WSN both using virtual or real hardware modules, such as the National Instruments Real-Time Module platform, the CompactRio, the Supervisory Control And Data Acquisition (SCADA), etc. To test the proposed solution, we decided to integrate it with one of the most popular simulators, i.e., the Contiki OS, and wireless motes, i.e., the Sky mote. As a further contribution, the Contiki Sky DAC driver and a new "Advanced Sky GUI" have been proposed and tested in the COOJA Simulator in order to provide the possibility to develop control over the WSN. To test the performances of the proposed GILOO software module, several experimental tests have been made, and interesting preliminary results are reported. The GILOO module has been applied to a smart home

  17. Using simulation to evaluate warhead monitoring system effectiveness

    SciTech Connect

    Perkins, Casey J.; Brigantic, Robert T.; Keating, Douglas H.; Liles, Karina R.; Meyer, Nicholas J.; Oster, Matthew R.; Waterworth, Angela M.

    2015-07-12

    There is a need to develop and demonstrate technical approaches for verifying potential future agreements to limit and reduce total warhead stockpiles. To facilitate this aim, warhead monitoring systems employ both concepts of operations (CONOPS) and technologies. A systems evaluation approach can be used to assess the relative performance of CONOPS and technologies in their ability to achieve monitoring system objectives which include: 1) confidence that a treaty accountable item (TAI) initialized by the monitoring system is as declared; 2) confidence that there is no undetected diversion from the monitoring system; and 3) confidence that a TAI is dismantled as declared. Although there are many quantitative methods that can be used to assess system performance for the above objectives, this paper focuses on a simulation perspective primarily for the ability to support analysis of the probabilities that are used to define operating characteristics of CONOPS and technologies. This paper describes a discrete event simulation (DES) model, comprised of three major sub-models: including TAI lifecycle flow, monitoring activities, and declaration behavior. The DES model seeks to capture all processes and decision points associated with the progressions of virtual TAIs, with notional characteristics, through the monitoring system from initialization through dismantlement. The simulation updates TAI progression (i.e., whether the generated test objects are accepted and rejected at the appropriate points) all the way through dismantlement. Evaluation of TAI lifecycles primarily serves to assess how the order, frequency, and combination of functions in the CONOPS affect system performance as a whole. It is important, however, to note that discrete event simulation is also capable (at a basic level) of addressing vulnerabilities in the CONOPS and interdependencies between individual functions as well. This approach is beneficial because it does not rely on complex mathematical

  18. Modeling emergency department operations using advanced computer simulation systems.

    PubMed

    Saunders, C E; Makens, P K; Leblanc, L J

    1989-02-01

    We developed a computer simulation model of emergency department operations using simulation software. This model uses multiple levels of preemptive patient priority; assigns each patient to an individual nurse and physician; incorporates all standard tests, procedures, and consultations; and allows patient service processes to proceed simultaneously, sequentially, repetitively, or a combination of these. Selected input data, including the number of physicians, nurses, and treatment beds, and the blood test turnaround time, then were varied systematically to determine their simulated effect on patient throughput time, selected queue sizes, and rates of resource utilization. Patient throughput time varied directly with laboratory service times and inversely with the number of physician or nurse servers. Resource utilization rates varied inversely with resource availability, and patient waiting time and patient throughput time varied indirectly with the level of patient acuity. The simulation can be animated on a computer monitor, showing simulated patients, specimens, and staff members moving throughout the ED. Computer simulation is a potentially useful tool that can help predict the results of changes in the ED system without actually altering it and may have implications for planning, optimizing resources, and improving the efficiency and quality of care.

  19. System design and description of infrared simulator system based on the multidimensional flight table

    NASA Astrophysics Data System (ADS)

    Huang, Chong; Chen, Haiqing; Li, Jun; Yang, Zhengang; Zhao, Shuang

    2008-12-01

    This paper deals with the simulation for the army aviation and missile command at the thermal infrared range scale from 2.0 to 4.9μm. The infrared simulator system based on the multidimensional flight table(ISSBMFT) is the significant part of hardware - in - the - loop (HWIL) simulation system for controlling and guiding weapon systems with infrared seekers. It emphasizes on the infrared scene of HWIL simulation experimentation for controlling and guiding weapon and provides a realistic environment of combat with target/jamming which owns the specific properties of radiant spectrum, entrance angle and target's relative distance variation. Optical system is the basis of the characteristics of the simulator. In the system, three-beam structure is put forward which will make the optical path equal. Through settling attenuators, filters, and polaroids in the beams, which modulates the transmittance, the energy proportion is simulated, so as wave energy and the entrance angle. So we can simulate one target and two different forms of jamming through various distance and conformations. Radiant system and controlling system is the guarantee of the simulation. Calculation of energy and the method of controlling is depicted in the article.

  20. The Numerical Propulsion System Simulation: A Multidisciplinary Design System for Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Lytle, John K.

    1999-01-01

    Advances in computational technology and in physics-based modeling are making large scale, detailed simulations of complex systems possible within the design environment. For example, the integration of computing, communications, and aerodynamics has reduced the time required to analyze ma or propulsion system components from days and weeks to minutes and hours. This breakthrough has enabled the detailed simulation of major propulsion system components to become a routine part of design process and to provide the designer with critical information about the components early in the design process. This paper describes the development of the Numerical Propulsion System Simulation (NPSS), a multidisciplinary system of analysis tools that is focussed on extending the simulation capability from components to the full system. This will provide the product developer with a "virtual wind tunnel" that will reduce the number of hardware builds and tests required during the development of advanced aerospace propulsion systems.

  1. Simulation of Benchmark Cases with the Terminal Area Simulation System (TASS)

    NASA Technical Reports Server (NTRS)

    Ahmad, Nashat N.; Proctor, Fred H.

    2011-01-01

    The hydrodynamic core of the Terminal Area Simulation System (TASS) is evaluated against different benchmark cases. In the absence of closed form solutions for the equations governing atmospheric flows, the models are usually evaluated against idealized test cases. Over the years, various authors have suggested a suite of these idealized cases which have become standards for testing and evaluating the dynamics and thermodynamics of atmospheric flow models. In this paper, simulations of three such cases are described. In addition, the TASS model is evaluated against a test case that uses an exact solution of the Navier-Stokes equations. The TASS results are compared against previously reported simulations of these benchmark cases in the literature. It is demonstrated that the TASS model is highly accurate, stable and robust.

  2. Simulation of Benchmark Cases with the Terminal Area Simulation System (TASS)

    NASA Technical Reports Server (NTRS)

    Ahmad, Nash'at; Proctor, Fred

    2011-01-01

    The hydrodynamic core of the Terminal Area Simulation System (TASS) is evaluated against different benchmark cases. In the absence of closed form solutions for the equations governing atmospheric flows, the models are usually evaluated against idealized test cases. Over the years, various authors have suggested a suite of these idealized cases which have become standards for testing and evaluating the dynamics and thermodynamics of atmospheric flow models. In this paper, simulations of three such cases are described. In addition, the TASS model is evaluated against a test case that uses an exact solution of the Navier-Stokes equations. The TASS results are compared against previously reported simulations of these banchmark cases in the literature. It is demonstrated that the TASS model is highly accurate, stable and robust.

  3. Expert systems and simulation models; Proceedings of the Seminar, Tucson, AZ, November 18, 19, 1985

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The seminar presents papers on modeling and simulation methodology, artificial intelligence and expert systems, environments for simulation/expert system development, and methodology for simulation/expert system development. Particular attention is given to simulation modeling concepts and their representation, modular hierarchical model specification, knowledge representation, and rule-based diagnostic expert system development. Other topics include the combination of symbolic and discrete event simulation, real time inferencing, and the management of large knowledge-based simulation projects.

  4. Network Flow Simulation of Fluid Transients in Rocket Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Bandyopadhyay, Alak; Hamill, Brian; Ramachandran, Narayanan; Majumdar, Alok

    2011-01-01

    Fluid transients, also known as water hammer, can have a significant impact on the design and operation of both spacecraft and launch vehicle propulsion systems. These transients often occur at system activation and shutdown. The pressure rise due to sudden opening and closing of valves of propulsion feed lines can cause serious damage during activation and shutdown of propulsion systems. During activation (valve opening) and shutdown (valve closing), pressure surges must be predicted accurately to ensure structural integrity of the propulsion system fluid network. In the current work, a network flow simulation software (Generalized Fluid System Simulation Program) based on Finite Volume Method has been used to predict the pressure surges in the feed line due to both valve closing and valve opening using two separate geometrical configurations. The valve opening pressure surge results are compared with experimental data available in the literature and the numerical results compared very well within reasonable accuracy (< 5%) for a wide range of inlet-to-initial pressure ratios. A Fast Fourier Transform is preformed on the pressure oscillations to predict the various modal frequencies of the pressure wave. The shutdown problem, i.e. valve closing problem, the simulation results are compared with the results of Method of Characteristics. Most rocket engines experience a longitudinal acceleration, known as "pogo" during the later stage of engine burn. In the shutdown example problem, an accumulator has been used in the feed system to demonstrate the "pogo" mitigation effects in the feed system of propellant. The simulation results using GFSSP compared very well with the results of Method of Characteristics.

  5. An online interactive simulation system for medical imaging education.

    PubMed

    Dikshit, Aditya; Wu, Dawei; Wu, Chunyan; Zhao, Weizhao

    2005-09-01

    This report presents a recently developed web-based medical imaging simulation system for teaching students or other trainees who plan to work in the medical imaging field. The increased importance of computer and information technology widely applied to different imaging techniques in clinics and medical research necessitates a comprehensive medical imaging education program. A complete tutorial of simulations introducing popular imaging modalities, such as X-ray, MRI, CT, ultrasound and PET, forms an essential component of such an education. Internet technologies provide a vehicle to carry medical imaging education online. There exist a number of internet-based medical imaging hyper-books or online documentations. However, there are few providing interactive computational simulations. We focus on delivering knowledge of the physical principles and engineering implementation of medical imaging techniques through an interactive website environment. The online medical imaging simulation system presented in this report outlines basic principles underlying different imaging techniques and image processing algorithms and offers trainees an interactive virtual laboratory. For education purposes, this system aims to provide general understanding of each imaging modality with comprehensive explanations, ample illustrations and copious references as its thrust, rather than complex physics or detailed math. This report specifically describes the development of the tutorial for commonly used medical imaging modalities. An internet-accessible interface is used to simulate various imaging algorithms with user-adjustable parameters. The tutorial is under the MATLAB Web Server environment. Macromedia Director MX is used to develop interactive animations integrating theory with graphic-oriented simulations. HTML and JavaScript are used to enable a user to explore these modules online in a web browser. Numerous multiple choice questions, links and references for advanced study are

  6. The infrared and semi-active laser simulation capabilities at the multi-spectral system simulation (MSS) HWIL facility

    NASA Astrophysics Data System (ADS)

    Saylor, Daniel A.; Terry, John; Morris, Joseph

    2008-04-01

    The Aviation and Missile Research, Engineering and Development Center (AMRDEC), System Simulation and Development Directorate (SS&DD) is developing a Hardware-in-the-Loop (HWIL) facility known as the Multi-spectral System Simulation (MSS). The simulation facility has the capability to simultaneously produce scenes in three spectral bands. This paper describes the Near Infrared (NIR) and Imaging Infrared capabilities of the MSS simulation.

  7. Evolutionary Development of the Simulation by Logical Modeling System (SIBYL)

    NASA Technical Reports Server (NTRS)

    Wu, Helen

    1995-01-01

    Through the evolutionary development of the Simulation by Logical Modeling System (SIBYL) we have re-engineered the expensive and complex IBM mainframe based Long-term Hardware Projection Model (LHPM) to a robust cost-effective computer based mode that is easy to use. We achieved significant cost reductions and improved productivity in preparing long-term forecasts of Space Shuttle Main Engine (SSME) hardware. The LHPM for the SSME is a stochastic simulation model that projects the hardware requirements over 10 years. SIBYL is now the primary modeling tool for developing SSME logistics proposals and Program Operating Plan (POP) for NASA and divisional marketing studies.

  8. Parachute system design, analysis, and simulation tool. Status report

    SciTech Connect

    Sundberg, W.D.; McBride, D.D.; Gwinn, K.W.; Waye, D.E.; Hailey, C.E.

    1992-12-31

    For over twenty years designers at Sandia National Laboratories have developed various parachute simulation codes to model deployment, inflation, loading, trajectories, aircraft downwash and line sail. In addition to these codes, material property data bases have been acquired. Recently we have initiated project to integrate these codes and data bases into a single software tool entitled SPARSYS (Sandia PARachute SYstem Simulation). We have constructed a graphical user interface as the driver and framework for SPARSYS. In this paper we present a status report on SPARSYS describing progress in developing and incorporating independent modules, in developing an integrated trajectory package, and in developing a materials data base including high-rate-of-strain data.

  9. INTEGRATED SYSTEM SIMULATION IN X-RAY RADIOGRAPHY

    SciTech Connect

    T. KWAN; ET AL

    2001-01-01

    An integrated simulation capability is being developed to examine the fidelity of a dynamic radiographic system. This capability consists of a suite of simulation codes which individually model electromagnetic and particle transport phenomena and are chained together to model an entire radiographic event. Our study showed that the electron beam spot size at the converter target plays the key role in determining material edge locations. The angular spectrum is a relatively insensitive factor in radiographic fidelity. We also found that the full energy spectrum of the imaging photons must be modeled to obtain an accurate analysis of material densities.

  10. Modeling and Simulation For A Variable Sprayerrate System

    NASA Astrophysics Data System (ADS)

    Shi, Yan; Liang, Anbo; Yuan, Haibo; Zhang, Chunmei; Li, Junlong

    Variable spraying technology is an important content and developing direction in current plant protection machinery, which can effectively save pesticide and lighten burden of ecological environment in agriculture according to characteristic of spraying targets and speed of aircraft crew. Paper established mathematic model and delivery function of variable spraying system based on designed hardware of variable spraying machine, making use of PID controlling algorithm to simulate in matlab. Simulating result explained that the model can conveniently control gushing amounts and can arrive at satisfied controlling.

  11. Modeling and Simulation For A Variable Sprayerrate System

    NASA Astrophysics Data System (ADS)

    Shi, Yan; Liang, Anbo; Yuan, Haibo; Zhang, Chunmei; Li, Junlong

    Variable spraying technology is an important content and developing direction in current plant protection machinery, which can effectively save pesticide and lighten burden of ecological environment in agriculture according to characteristic of spraying targets and speed of aircraft crew. Paper established mathematic model and delivery function of variable spraying system based on designed hardware of variable spraying machine, making use of PID controlling algorithm to simulate in MATLAB. Simulating result explained that the model can conveniently control gushing amounts and can arrive at satisfied controlling.

  12. Simulation of Combustion Systems with Realistic g-Jitter

    NASA Technical Reports Server (NTRS)

    Mell, William E.; McGrattan, Kevin B.; Baum, Howard R.

    1999-01-01

    A number of facilities are available for microgravity combustion experiments: aircraft, drop tower, sounding rocket, space shuttle and, in the future, the international space station (ISS). Acceleration disturbances or g-jitter about the background level of reduced gravity exist in all the microgravity facilities. While g-jitter is routinely measured, a quantitative comparison of the quality of g-jitter among the different microgravity facilities has not been compiled. Low frequency g-jitter (< 1 Hz) has been repeatedly observed to disturb a number of combustion systems. Guidelines regarding tolerable levels of acceleration disturbances for a given combustion system have been developed for use in the design of ISS experiments. The validity of these guidelines, however, remains unknown. In this project, recently funded by NASA, a transient, fully three-dimensional simulation code will be developed to simulate the effects of realistic g-jitter on a number of combustion systems. Acceleration disturbances of realistic orientation, magnitude and time dependence will be included in the simulation. Since this is a newly funded project with code development just under-way no simulation results will be presented. Instead, first a short review of the relevant background concerning g-jitter will be given followed by a section on the proposed technical approach.

  13. Simulation of Energy Management Systems in EnergyPlus

    SciTech Connect

    Ellis, P. G.; Torcellini, P. A.; Crawley, D.

    2008-01-01

    An energy management system (EMS) is a dedicated computer that can be programmed to control all of a building's energy-related systems, including heating, cooling, ventilation, hot water, interior lighting, exterior lighting, on-site power generation, and mechanized systems for shading devices, window actuators, and double facade elements. Recently a new module for simulating an EMS was added to the EnergyPlus whole-building energy simulation program. An essential part of the EMS module is the EnergyPlus Runtime Language (ERL), which is a simple programming language that is used to specify the EMS control algorithms. The new EMS controls and the flexibility of ERL allow EnergyPlus to simulate many novel control strategies that are not possible with the previous generation of building energy simulation programs. This paper surveys the standard controls in EnergyPlus, presents the new EMS features, describes the implementation of the module, and explores some of the possible applications for the new EMS capabilities in EnergyPlus.

  14. Big Data Visual Analytics for Exploratory Earth System Simulation Analysis

    SciTech Connect

    Steed, Chad A.; Ricciuto, Daniel M.; Shipman, Galen M.; Smith, Brian E.; Thornton, Peter E.; Wang, Dali; Shi, Xiaoying; Williams, Dean N.

    2013-12-01

    Rapid increases in high performance computing are feeding the development of larger and more complex data sets in climate research, which sets the stage for so-called big data analysis challenges. However, conventional climate analysis techniques are inadequate in dealing with the complexities of today s data. In this paper, we describe and demonstrate a visual analytics system, called the Exploratory Data analysis ENvironment (EDEN), with specific application to the analysis of complex earth system simulation data sets. EDEN represents the type of interactive visual analysis tools that are necessary to transform data into insight, thereby improving critical comprehension of earth system processes. In addition to providing an overview of EDEN, we describe real-world studies using both point ensembles and global Community Land Model Version 4 (CLM4) simulations.

  15. Digital simulation of dynamic processes in radiometer systems. [microwave radiometers

    NASA Technical Reports Server (NTRS)

    Stanley, W. D.

    1980-01-01

    The development and application of several computer programs for simulating different classes of microwave radiometers are described. The programs are dynamic in nature, and they may be used to determine the instantaneous behavior of system variables as a function of time. Some of the programs employ random variable models in the simulations so that the statistical nature of the results may be investigated. The programs have been developed to utilize either the Continuous System Modeling Program or the Advanced Continuous System Language. The validity of most of the programs was investigated using statistical tests, and the results show excellent correlation with theoretical predictions. The programs are currently being used in the investigation of new design techniques for microwave radiometers.

  16. Performance calculation and simulation system of high energy laser weapon

    NASA Astrophysics Data System (ADS)

    Wang, Pei; Liu, Min; Su, Yu; Zhang, Ke

    2014-12-01

    High energy laser weapons are ready for some of today's most challenging military applications. Based on the analysis of the main tactical/technical index and combating process of high energy laser weapon, a performance calculation and simulation system of high energy laser weapon was established. Firstly, the index decomposition and workflow of high energy laser weapon was proposed. The entire system was composed of six parts, including classical target, platform of laser weapon, detect sensor, tracking and pointing control, laser atmosphere propagation and damage assessment module. Then, the index calculation modules were designed. Finally, anti-missile interception simulation was performed. The system can provide reference and basis for the analysis and evaluation of high energy laser weapon efficiency.

  17. Simulation of GRM drag compensation system. [Geopotential Research Mission

    NASA Technical Reports Server (NTRS)

    Antreasian, Peter G.; Lundberg, John B.; Schutz, Bob E.

    1991-01-01

    NASA's Geopotential Research Mission (GRM) was proposed in 1986 for globally determining the earth's gravitational and magnetic fields with high precision via full earth coverage polar-orbit satellites. In the GRM system, at least one of the two satellites was required to be stationed in a low-altitude, 160-km orbit subject to atmospheric drag effects that could both corrupt gravity measurements and reduce the satellite's lifetime. The Disturbance Compensation System, 'DISCOS', was incorporated to select a drag-free orbit during the active portion of GRM satellite operations by firing thrusters that offset the effects of disturbances. A drag-free thruster algorithm has been created to simulate the DISCOS system; simulation results are presented.

  18. Modelling and simulation of vehicle electric power system

    NASA Astrophysics Data System (ADS)

    Lee, Wootaik; Choi, Daeho; Sunwoo, Myoungho

    In recent years, the demand for an increased number of vehicle functions by legislation and customer expectations has introduced many electronic control systems and electrical driven units in vehicles and has resulted in steadily increasing electrical loads. Moreover, due to heavy urban traffic conditions, the idling time fraction has increased and reduced the power generation of the alternator. In the vehicle design phase, in order to avoid an over- or under-design problem of the electric power system, it is necessary to understand both the characteristics of each component of the vehicle electric power system and the interactions between the components. For this purpose, model and simulation algorithms of the vehicle power system are required. In this study, the vehicle electric power system, which is mainly composed of a generator and battery, is modelled and evaluated. Among the various proposed battery models, two types are compared in terms of accuracy and ease-of-use. These two models are distinguished by the consideration of inrush current at the beginning of charging and discharging. In addition, a variable terminal voltage alternator model (VTVA model) is proposed, and is compared with a constant terminal voltage alternator model (CTVA model). Based on the major component model, a simulation algorithm is developed and used to perform a case study. Compared with real data from the vehicle, the simulation results of energy generation and consumption are comparable.

  19. UAS-Systems Integration, Validation, and Diagnostics Simulation Capability

    NASA Technical Reports Server (NTRS)

    Buttrill, Catherine W.; Verstynen, Harry A.

    2014-01-01

    As part of the Phase 1 efforts of NASA's UAS-in-the-NAS Project a task was initiated to explore the merits of developing a system simulation capability for UAS to address airworthiness certification requirements. The core of the capability would be a software representation of an unmanned vehicle, including all of the relevant avionics and flight control system components. The specific system elements could be replaced with hardware representations to provide Hardware-in-the-Loop (HWITL) test and evaluation capability. The UAS Systems Integration and Validation Laboratory (UAS-SIVL) was created to provide a UAS-systems integration, validation, and diagnostics hardware-in-the-loop simulation capability. This paper discusses how SIVL provides a robust and flexible simulation framework that permits the study of failure modes, effects, propagation paths, criticality, and mitigation strategies to help develop safety, reliability, and design data that can assist with the development of certification standards, means of compliance, and design best practices for civil UAS.

  20. Simulation Environment for Orion Launch Abort System Control Design Studies

    NASA Technical Reports Server (NTRS)

    McMinn, J. Dana; Jackson, E. Bruce; Christhilf, David M.

    2007-01-01

    The development and use of an interactive environment to perform control system design and analysis of the proposed Crew Exploration Vehicle Launch Abort System is described. The environment, built using a commercial dynamic systems design package, includes use of an open-source configuration control software tool and a collaborative wiki to coordinate between the simulation developers, control law developers and users. A method for switching between multiple candidate control laws and vehicle configurations is described. Aerodynamic models, especially in a development program, change rapidly, so a means for automating the implementation of new aerodynamic models is described.

  1. Experimental Validation of a Closed Brayton Cycle System Transient Simulation

    NASA Technical Reports Server (NTRS)

    Johnson, Paul K.; Hervol, David S.

    2006-01-01

    The Brayton Power Conversion Unit (BPCU) located at NASA Glenn Research Center (GRC) in Cleveland, Ohio was used to validate the results of a computational code known as Closed Cycle System Simulation (CCSS). Conversion system thermal transient behavior was the focus of this validation. The BPCU was operated at various steady state points and then subjected to transient changes involving shaft rotational speed and thermal energy input. These conditions were then duplicated in CCSS. Validation of the CCSS BPCU model provides confidence in developing future Brayton power system performance predictions, and helps to guide high power Brayton technology development.

  2. Observing System Simulation Experiments for Fun and Profit

    NASA Technical Reports Server (NTRS)

    Prive, Nikki C.

    2015-01-01

    Observing System Simulation Experiments can be powerful tools for evaluating and exploring both the behavior of data assimilation systems and the potential impacts of future observing systems. With great power comes great responsibility - given a pure modeling framework, how can we be sure our results are meaningful? The challenges and pitfalls of OSSE calibration and validation will be addressed, as well as issues of incestuousness, selection of appropriate metrics, and experiment design. The use of idealized observational networks to investigate theoretical ideas in a fully complex modeling framework will also be discussed

  3. SPS phase control system performance via analytical simulation

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Kantak, A. V.; Chie, C. M.; Booth, R. W. D.

    1979-01-01

    A solar power satellite transmission system which incorporates automatic beam forming, steering, and phase control is discussed. The phase control concept centers around the notation of an active retrodirective phased array as a means of pointing the beam to the appropriate spot on Earth. The transmitting antenna (spacetenna) directs the high power beam so that it focuses on the ground-based receiving antenna (rectenna). A combination of analysis and computerized simulation was conducted to determine the far field performance of the reference distribution system, and the beam forming and microwave power generating systems.

  4. Experimental Validation of a Closed Brayton Cycle System Transient Simulation

    NASA Astrophysics Data System (ADS)

    Johnson, Paul K.; Hervol, David S.

    2006-01-01

    The Brayton Power Conversion Unit (BPCU) located at NASA Glenn Research Center (GRC) in Cleveland, OH was used to validate the results of a computational code known as Closed Cycle System Simulation (CCSS). Conversion system thermal transient behavior was the focus of this validation. The BPCU was operated at various steady state points and then subjected to transient changes involving shaft rotational speed and thermal energy input. These conditions were then duplicated in CCSS. Validation of the CCSS BPCU model provides confidence in developing future Brayton power system performance predictions, and helps to guide high power Brayton technology development.

  5. Design distributed simulation platform for vehicle management system

    NASA Astrophysics Data System (ADS)

    Wen, Zhaodong; Wang, Zhanlin; Qiu, Lihua

    2006-11-01

    Next generation military aircraft requires the airborne management system high performance. General modules, data integration, high speed data bus and so on are needed to share and manage information of the subsystems efficiently. The subsystems include flight control system, propulsion system, hydraulic power system, environmental control system, fuel management system, electrical power system and so on. The unattached or mixed architecture is changed to integrated architecture. That means the whole airborne system is regarded into one system to manage. So the physical devices are distributed but the system information is integrated and shared. The process function of each subsystem are integrated (including general process modules, dynamic reconfiguration), furthermore, the sensors and the signal processing functions are shared. On the other hand, it is a foundation for power shared. Establish a distributed vehicle management system using 1553B bus and distributed processors which can provide a validation platform for the research of airborne system integrated management. This paper establishes the Vehicle Management System (VMS) simulation platform. Discuss the software and hardware configuration and analyze the communication and fault-tolerant method.

  6. Complex simulation system infrastructure supporting composability and performance

    NASA Astrophysics Data System (ADS)

    Dorsch, Matthew; Hannibal, Barbara; Skowronski, Victor; Wallace, Jeffrey

    2004-08-01

    The increased emphasis on the need for composability in simulations has led to architectures with server simulations that provide a service to several other simulations. One such architecture was the Joint Synthetic Battlespace (JSB) Spring Experiment 2002 architecture, which included a Common Synthetic Environment (CSE) server for atmospheric effects. The intent of using a CSE was to provide a standard model for all atmospheric effects. The common model would assist in the evaluation of sensor systems by removing any bias due to different environmental effects models. When the CSE server was proposed, it became apparent that the number of requests for environmental effect calculations might overwhelm the server, or cause excessive network activity. This paper examines the ability of the current architecture to scale operational levels. The paper also proposes modifications to the current architecture that can enhance the scalability of the architecture without impairing its composability.

  7. Real-time, interactive, visually updated simulator system for telepresence

    NASA Technical Reports Server (NTRS)

    Schebor, Frederick S.; Turney, Jerry L.; Marzwell, Neville I.

    1991-01-01

    Time delays and limited sensory feedback of remote telerobotic systems tend to disorient teleoperators and dramatically decrease the operator's performance. To remove the effects of time delays, key components were designed and developed of a prototype forward simulation subsystem, the Global-Local Environment Telerobotic Simulator (GLETS) that buffers the operator from the remote task. GLETS totally immerses an operator in a real-time, interactive, simulated, visually updated artificial environment of the remote telerobotic site. Using GLETS, the operator will, in effect, enter into a telerobotic virtual reality and can easily form a gestalt of the virtual 'local site' that matches the operator's normal interactions with the remote site. In addition to use in space based telerobotics, GLETS, due to its extendable architecture, can also be used in other teleoperational environments such as toxic material handling, construction, and undersea exploration.

  8. An intelligent simulation environment for control system design

    SciTech Connect

    Robinson, J.T.

    1989-01-01

    The Oak Ridge National Laboratory is currently assisting in the development of advanced control systems for the next generation of nuclear power plants. This paper presents a prototype interactive and intelligent simulation environment being developed to support this effort. The environment combines tools from the field of Artificial Intelligence; in particular object-oriented programming, a LISP programming environment, and a direct manipulation user interface; with traditional numerical methods for simulating combined continuous/discrete processes. The resulting environment is highly interactive and easy to use. Models may be created and modified quickly through a window oriented direct manipulation interface. Models may be modified at any time, even as the simulation is running, and the results observed immediately via real-time graphics. 8 refs., 3 figs.

  9. Aerodynamic thermal simulation system. Part 1: Radiant array (instruction manual)

    NASA Technical Reports Server (NTRS)

    Kitchar, A. F.; Steuffen, R. L.

    1973-01-01

    An aerodynamic thermal simulation system (ATSS) is presented. The construction of the system, the maintenance, set up, and operations are reported. System description of the radiant array is given along with the array subsystems modular heating unit, adjustable stanchion frame, cooling water system, and the gaseous nitrogen cooling system. The array configuration procedure outlines the set up and the start up. Maintenance procedures involve both lamp maintenance and reflector maintenance along with weather protection. Drawing codes are included. Descriptions of the 36 zone ATSS controls are also given. Each zone is an independent closed loop temperature control circuit. Procedures are presented for starting and stopping the system. The DATA-TRAK programmer and its operation, instruction manuals for the temperature controller and the power regulator and discriptions of peripheral equipment are discussed.

  10. Generic solar photovoltaic system dynamic simulation model specification.

    SciTech Connect

    Ellis, Abraham; Behnke, Michael Robert; Elliott, Ryan Thomas

    2013-10-01

    This document is intended to serve as a specification for generic solar photovoltaic (PV) system positive-sequence dynamic models to be implemented by software developers and approved by the WECC MVWG for use in bulk system dynamic simulations in accordance with NERC MOD standards. Two specific dynamic models are included in the scope of this document. The first, a Central Station PV System model, is intended to capture the most important dynamic characteristics of large scale (> 10 MW) PV systems with a central Point of Interconnection (POI) at the transmission level. The second, a Distributed PV System model, is intended to represent an aggregation of smaller, distribution-connected systems that comprise a portion of a composite load that might be modeled at a transmission load bus.

  11. SIMWEST - A simulation model for wind energy storage systems

    NASA Technical Reports Server (NTRS)

    Edsinger, R. W.; Warren, A. W.; Gordon, L. H.; Chang, G. C.

    1978-01-01

    This paper describes a comprehensive and efficient computer program for the modeling of wind energy systems with storage. The level of detail of SIMWEST (SImulation Model for Wind Energy STorage) is consistent with evaluating the economic feasibility as well as the general performance of wind energy systems with energy storage options. The software package consists of two basic programs and a library of system, environmental, and control components. The first program is a precompiler which allows the library components to be put together in building block form. The second program performs the technoeconomic system analysis with the required input/output, and the integration of system dynamics. An example of the application of the SIMWEST program to a current 100 kW wind energy storage system is given.

  12. Development of walking pattern evaluation system for hypogravity simulation.

    PubMed

    Leães, R; Cambraia, R; Bacim, F; Dalmarco, G; Calder, A; De Azevedo, D F G; Pinho, M; Russomano, T

    2006-01-01

    This study aimed to develop a Walking Pattern Evaluation System during Hypogravity Simulation (SAMSH), which included the adaptation of a body suspension device, the instrumentation of a treadmill and the development of a virtual environment. SAMSH was developed using one subject. Kinematic analyses were performed whilst one individual was walking on the treadmill during body weight reduction simulating the gravitational forces of the Moon (reduction of 60%) and Mars (reduction of 30%) with and without virtual reality glasses (Head Mounted Display, HMD). The walking pattern was evaluated by means of knee and ankle electrogoniometers, foot switches placed on the front and back part of the plantar region, and five video cameras. Results showed that the body weight reduction during Moon simulation alter the walking pattern, including the increase in step time, contact time, step length and aerial time, and the decrease of walking cadence time (steps per minute). The findings of this study also suggested that hypogravity simulation reduces walking effort. The utilization of the HMD allowed the evaluation of the head position three-dimensionally during hypogravity simulation. The virtual environment reduced postural balance, due to the absence of visual input, which was evidenced by a protective extension reaction.

  13. Physical habitat simulation system reference manual: version II

    USGS Publications Warehouse

    Milhous, Robert T.; Updike, Marlys A.; Schneider, Diane M.

    1989-01-01

    There are four major components of a stream system that determine the productivity of the fishery (Karr and Dudley 1978). These are: (1) flow regime, (2) physical habitat structure (channel form, substrate distribution, and riparian vegetation), (3) water quality (including temperature), and (4) energy inputs from the watershed (sediments, nutrients, and organic matter). The complex interaction of these components determines the primary production, secondary production, and fish population of the stream reach. The basic components and interactions needed to simulate fish populations as a function of management alternatives are illustrated in Figure I.1. The assessment process utilizes a hierarchical and modular approach combined with computer simulation techniques. The modular components represent the "building blocks" for the simulation. The quality of the physical habitat is a function of flow and, therefore, varies in quality and quantity over the range of the flow regime. The conceptual framework of the Incremental Methodology and guidelines for its application are described in "A Guide to Stream Habitat Analysis Using the Instream Flow Incremental Methodology" (Bovee 1982). Simulation of physical habitat is accomplished using the physical structure of the stream and streamflow. The modification of physical habitat by temperature and water quality is analyzed separately from physical habitat simulation. Temperature in a stream varies with the seasons, local meteorological conditions, stream network configuration, and the flow regime; thus, the temperature influences on habitat must be analysed on a stream system basis. Water quality under natural conditions is strongly influenced by climate and the geological materials, with the result that there is considerable natural variation in water quality. When we add the activities of man, the possible range of water quality possibilities becomes rather large. Consequently, water quality must also be analysed on a

  14. Dynamical simulations of the HR8799 planetary system

    NASA Astrophysics Data System (ADS)

    Marshall, J.; Horner, J.; Carter, A.

    2010-10-01

    HR8799 is a young (20-160 Myr) A-dwarf main sequence star with a debris disc detected by IRAS (InfraRed Astronomical Satellite). In 2008, it was one of two stars around which exoplanets were directly imaged for the first time. The presence of three Jupiter-mass planets around HR8799 provoked much interest in modelling the dynamical stability of the system. Initial simulations indicated that the observed planetary architecture was unstable on timescales much shorter than the lifetime of the star (~105 yr). Subsequent models suggested that the system could be stable if the planets were locked in a 1:2:4 mutual mean motion resonance (MMR). In this work, we have examined the influence of varying orbital eccentricity and the semi-major axis on the stability of the three-planet system, through dynamical simulations using the MERCURY n-body integrator. We find that, in agreement with previous work on this system, the 1:2:4 MMR is the most stable planetary configuration, and that the system stability is dominated by the interaction between the inner pair of planets. In contrast to previous results, we find that with small eccentricities, the three-planet system can be stable for timescales comparable to the system lifetime and, potentially, much longer.

  15. Hybrid stochastic simulations of intracellular reaction-diffusion systems

    PubMed Central

    Kalantzis, Georgios

    2009-01-01

    With the observation that stochasticity is important in biological systems, chemical kinetics have begun to receive wider interest. While the use of Monte Carlo discrete event simulations most accurately capture the variability of molecular species, they become computationally costly for complex reaction-diffusion systems with large populations of molecules. On the other hand, continuous time models are computationally efficient but they fail to capture any variability in the molecular species. In this study a novel hybrid stochastic approach is introduced for simulating reaction-diffusion systems. We developed a dynamic partitioning strategy using fractional propensities. In that way processes with high frequency are simulated mostly with deterministic rate-based equations, and those with low frequency mostly with the exact stochastic algorithm of Gillespie. In this way we preserve the stochastic behavior of cellular pathways while being able to apply it to large populations of molecules. In this article we describe this hybrid algorithmic approach, and we demonstrate its accuracy and efficiency compared with the Gillespie algorithm for two different systems. First, a model of intracellular viral kinetics with two steady states and second, a compartmental model of the postsynaptic spine head for studying the dynamics of Ca+2 and NMDA receptors. PMID:19414282

  16. Discrete Stochastic Simulation Methods for Chemically Reacting Systems

    PubMed Central

    Cao, Yang; Samuels, David C.

    2012-01-01

    Discrete stochastic chemical kinetics describe the time evolution of a chemically reacting system by taking into account the fact that in reality chemical species are present with integer populations and exhibit some degree of randomness in their dynamical behavior. In recent years, with the development of new techniques to study biochemistry dynamics in a single cell, there are increasing studies using this approach to chemical kinetics in cellular systems, where the small copy number of some reactant species in the cell may lead to deviations from the predictions of the deterministic differential equations of classical chemical kinetics. This chapter reviews the fundamental theory related to stochastic chemical kinetics and several simulation methods that are based on that theory. We focus on non-stiff biochemical systems and the two most important discrete stochastic simulation methods: Gillespie's Stochastic Simulation Algorithm (SSA) and the tau-leaping method. Different implementation strategies of these two methods are discussed. Then we recommend a relatively simple and efficient strategy that combines the strengths of the two methods: the hybrid SSA/tau-leaping method. The implementation details of the hybrid strategy are given here and a related software package is introduced. Finally, the hybrid method is applied to simple biochemical systems as a demonstration of its application. PMID:19216925

  17. Efficient simulation of stochastically-driven quantum systems

    NASA Astrophysics Data System (ADS)

    Sarovar, Mohan; Grace, Matthew

    2013-03-01

    The simulation of noisy quantum systems is critical for accurate modeling of many experiments, including those implementing quantum information tasks. The expansion of a stochastic equation for the coupled evolution of a quantum system and an Ornstein-Uhlenbeck process into a hierarchy of coupled differential equations is a useful technique that simplifies the simulation of stochastically-driven quantum systems. We expand the applicability of this technique by completely characterizing the class of diffusive Markov processes for which a useful hierarchy of equations can be derived. The expansion of this technique enables the examination of quantum systems driven by non-Gaussian stochastic processes with bounded range. We present an application of this extended technique by simulating Stark-tuned Forster resonance transfer in Rydberg atoms with non-perturbative position fluctuations. The work was supported by the Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  18. A space systems perspective of graphics simulation integration

    NASA Technical Reports Server (NTRS)

    Brown, R.; Gott, C.; Sabionski, G.; Bochsler, D.

    1987-01-01

    Creation of an interactive display environment can expose issues in system design and operation not apparent from nongraphics development approaches. Large amounts of information can be presented in a short period of time. Processes can be simulated and observed before committing resources. In addition, changes in the economics of computing have enabled broader graphics usage beyond traditional engineering and design into integrated telerobotics and Artificial Intelligence (AI) applications. The highly integrated nature of space operations often tend to rely upon visually intensive man-machine communication to ensure success. Graphics simulation activities at the Mission Planning and Analysis Division (MPAD) of NASA's Johnson Space Center are focusing on the evaluation of a wide variety of graphical analysis within the context of present and future space operations. Several telerobotics and AI applications studies utilizing graphical simulation are described. The presentation includes portions of videotape illustrating technology developments involving: (1) coordinated manned maneuvering unit and remote manipulator system operations, (2) a helmet mounted display system, and (3) an automated rendezous application utilizing expert system and voice input/output technology.

  19. The Development of A Human Systems Simulation Laboratory: Strategic Direction

    SciTech Connect

    Jacques Hugo; Katya le Blanc; David Gertman

    2012-07-01

    The Human System Simulation Laboratory (HSSL) at the Idaho National Laboratory is one of few facilities of its kind that allows human factors researchers to evaluate various aspects of human performance and human system interaction for proposed reactor designs and upgrades. A basic system architecture, physical configuration and simulation capability were established to enable human factors researchers to support multiple, simultaneous simulations and also different power plant technologies. Although still evolving in terms of its technical and functional architecture, the HSSL is already proving its worth in supporting current and future nuclear industry needs for light water reactor sustainability and small modular reactors. The evolution of the HSSL is focused on continual physical and functional refinement to make it a fully equipped, reconfigurable facility where advanced research, testing and validation studies can be conducted on a wider range of reactor technologies. This requires the implementation of additional plant models to produce empirical research data on human performance with emerging human-system interaction technologies. Additional beneficiaries of this information include system designers and HRA practitioners. To ensure that results of control room crew studies will be generalizable to the existing and evolving fleet of US reactors, future expansion of the HSSL may also include other SMR plant models, plant-specific simulators and a generic plant model aligned to the current generation of pressurized water reactors (PWRs) and future advanced reactor designs. Collaboration with industry partners is also proving to be a vital component of the facility as this helps to establish a formal basis for current and future human performance experiments to support nuclear industry objectives. A long-range Program Plan has been developed for the HSSL to ensure that the facility will support not only the Department of Energy’s Light Water Reactor

  20. Automatic mathematical modeling for real time simulation system

    NASA Technical Reports Server (NTRS)

    Wang, Caroline; Purinton, Steve

    1988-01-01

    A methodology for automatic mathematical modeling and generating simulation models is described. The models will be verified by running in a test environment using standard profiles with the results compared against known results. The major objective is to create a user friendly environment for engineers to design, maintain, and verify their model and also automatically convert the mathematical model into conventional code for conventional computation. A demonstration program was designed for modeling the Space Shuttle Main Engine Simulation. It is written in LISP and MACSYMA and runs on a Symbolic 3670 Lisp Machine. The program provides a very friendly and well organized environment for engineers to build a knowledge base for base equations and general information. It contains an initial set of component process elements for the Space Shuttle Main Engine Simulation and a questionnaire that allows the engineer to answer a set of questions to specify a particular model. The system is then able to automatically generate the model and FORTRAN code. The future goal which is under construction is to download the FORTRAN code to VAX/VMS system for conventional computation. The SSME mathematical model will be verified in a test environment and the solution compared with the real data profile. The use of artificial intelligence techniques has shown that the process of the simulation modeling can be simplified.

  1. Measures for simulator evaluation of a helicopter obstacle avoidance system

    NASA Technical Reports Server (NTRS)

    Demaio, Joe; Sharkey, Thomas J.; Kennedy, David; Hughes, Micheal; Meade, Perry

    1993-01-01

    The U.S. Army Aeroflightdynamics Directorate (AFDD) has developed a high-fidelity, full-mission simulation facility for the demonstration and evaluation of advanced helicopter mission equipment. The Crew Station Research and Development Facility (CSRDF) provides the capability to conduct one- or two-crew full-mission simulations in a state-of-the-art helicopter simulator. The CSRDF provides a realistic, full field-of-regard visual environment with simulation of state-of-the-art weapons, sensors, and flight control systems. We are using the CSRDF to evaluate the ability of an obstacle avoidance system (OASYS) to support low altitude flight in cluttered terrain using night vision goggles (NVG). The OASYS uses a laser radar to locate obstacles to safe flight in the aircraft's flight path. A major concern is the detection of wires, which can be difficult to see with NVG, but other obstacles--such as trees, poles or the ground--are also a concern. The OASYS symbology is presented to the pilot on a head-up display mounted on the NVG (NVG-HUD). The NVG-HUD presents head-stabilized symbology to the pilot while allowing him to view the image intensified, out-the-window scene through the HUD. Since interference with viewing through the display is a major concern, OASYS symbology must be designed to present usable obstacle clearance information with a minimum of clutter.

  2. Encapsulated membrane proteins: A simplified system for molecular simulation.

    PubMed

    Lee, Sarah C; Khalid, Syma; Pollock, Naomi L; Knowles, Tim J; Edler, Karen; Rothnie, Alice J; R T Thomas, Owen; Dafforn, Timothy R

    2016-10-01

    Over the past 50years there has been considerable progress in our understanding of biomolecular interactions at an atomic level. This in turn has allowed molecular simulation methods employing full atomistic modelling at ever larger scales to develop. However, some challenging areas still remain where there is either a lack of atomic resolution structures or where the simulation system is inherently complex. An area where both challenges are present is that of membranes containing membrane proteins. In this review we analyse a new practical approach to membrane protein study that offers a potential new route to high resolution structures and the possibility to simplify simulations. These new approaches collectively recognise that preservation of the interaction between the membrane protein and the lipid bilayer is often essential to maintain structure and function. The new methods preserve these interactions by producing nano-scale disc shaped particles that include bilayer and the chosen protein. Currently two approaches lead in this area: the MSP system that relies on peptides to stabilise the discs, and SMALPs where an amphipathic styrene maleic acid copolymer is used. Both methods greatly enable protein production and hence have the potential to accelerate atomic resolution structure determination as well as providing a simplified format for simulations of membrane protein dynamics. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg. PMID:26946242

  3. A New Model to Simulate Energy Performance of VRF Systems

    SciTech Connect

    Hong, Tianzhen; Pang, Xiufeng; Schetrit, Oren; Wang, Liping; Kasahara, Shinichi; Yura, Yoshinori; Hinokuma, Ryohei

    2014-03-30

    This paper presents a new model to simulate energy performance of variable refrigerant flow (VRF) systems in heat pump operation mode (either cooling or heating is provided but not simultaneously). The main improvement of the new model is the introduction of the evaporating and condensing temperature in the indoor and outdoor unit capacity modifier functions. The independent variables in the capacity modifier functions of the existing VRF model in EnergyPlus are mainly room wet-bulb temperature and outdoor dry-bulb temperature in cooling mode and room dry-bulb temperature and outdoor wet-bulb temperature in heating mode. The new approach allows compliance with different specifications of each indoor unit so that the modeling accuracy is improved. The new VRF model was implemented in a custom version of EnergyPlus 7.2. This paper first describes the algorithm for the new VRF model, which is then used to simulate the energy performance of a VRF system in a Prototype House in California that complies with the requirements of Title 24 ? the California Building Energy Efficiency Standards. The VRF system performance is then compared with three other types of HVAC systems: the Title 24-2005 Baseline system, the traditional High Efficiency system, and the EnergyStar Heat Pump system in three typical California climates: Sunnyvale, Pasadena and Fresno. Calculated energy savings from the VRF systems are significant. The HVAC site energy savings range from 51 to 85percent, while the TDV (Time Dependent Valuation) energy savings range from 31 to 66percent compared to the Title 24 Baseline Systems across the three climates. The largest energy savings are in Fresno climate followed by Sunnyvale and Pasadena. The paper discusses various characteristics of the VRF systems contributing to the energy savings. It should be noted that these savings are calculated using the Title 24 prototype House D under standard operating conditions. Actual performance of the VRF systems for real

  4. Virtual reality robotic telesurgery simulations using MEMICA haptic system

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Mavroidis, Constantinos; Bouzit, Mourad; Dolgin, Benjamin; Harm, Deborah L.; Kopchok, George E.; White, Rodney

    2001-01-01

    The authors conceived a haptic mechanism called MEMICA (Remote Mechanical Mirroring using Controlled stiffness and Actuators) that can enable the design of high dexterity, rapid response, and large workspace haptic system. The development of a novel MEMICA gloves and virtual reality models are being explored to allow simulation of telesurgery and other applications. The MEMICA gloves are being designed to provide intuitive mirroring of the conditions at a virtual site where a robot simulates the presence of a human operator. The key components of MEMICA are miniature electrically controlled stiffness (ECS) elements and electrically controlled force and stiffness (ECFS) actuators that are based on the use of Electro-Rheological Fluids (ERF. In this paper the design of the MEMICA system and initial experimental results are presented.

  5. Study of the Time Response of a Simulated Hydroelectric System

    NASA Astrophysics Data System (ADS)

    Simani, S.; Alvisi, S.; Venturini, M.

    2014-12-01

    This paper addresses the design of an advanced control strategy for a typical hydroelectric dynamic process, performed in the Matlab and Simulink environments. The hydraulic system consists of a high water head and a long penstock with upstream and downstream surge tanks, and is equipped with a Francis turbine. The nonlinear characteristics of hydraulic turbine and the inelastic water hammer effects were considered to calculate and simulate the hydraulic transients. With reference to the control solution, the proposed methodology relies on an adaptive control designed by means of the on-line identification of the system model under monitoring. Extensive simulations and comparison with respect to a classic hydraulic turbine speed PID regulator show the effectiveness of the proposed modelling and control tools.

  6. Hydrodynamic Simulations of Close and Contact Binary Systems using Bipolytropes

    NASA Astrophysics Data System (ADS)

    Kadam, Kundan

    2016-01-01

    I will present the results of hydrodynamic simulations of close and contact bipolytropic binary systems. This project is motivated by the peculiar case of the red nova, V1309 Sco, which is indeed a merger of a contact binary. Both the stars are believed to have evolved off the main sequence by the time of the merger and possess a small helium core. In order to represent the binary accurately, I need a core-envelope structure for both the stars. I have achieved this using bipolytropes or composite polytropes. For the simulations, I use an explicit 3D Eulerian hydrodynamics code in cylindrical coordinates. I will discuss the evolution and merger scenarios of systems with different mass ratios and core mass fractions as well as the effects due to the treatment of the adiabatic exponent.

  7. Space simulation experiments on reaction control system thruster plumes

    NASA Technical Reports Server (NTRS)

    Cassidy, J. F.

    1972-01-01

    A space simulation procedure was developed for studying rocket plume contamination effects using a 5-pound bipropellant reaction control system thruster. Vacuum chamber pressures of 3 x 10 to the minus 5 torr (70 miles altitude) were achieved with the thruster firing in pulse trains consisting of eight pulses (50 msec on, 100 msec off, and seven minutes between pulse trains). The final vacuum was achieved by cooling all vacuum chamber surfaces to liquid helium temperature and by introducing a continuous argon leak of 48 std. cc/sec into the test chamber. An effort was made to simulate propellant system flow dynamics corresponding to actual spacecraft mission use. Fast time response liquid flow rate measurements showed that large variations occurred in the ratio of oxidizer to fuel flow for pulse-on times up to 120 msec. These variations could lead to poor combustion efficiency and the production of contamination.

  8. Code System to Simulate 3D Tracer Dispersion in Atmosphere.

    2002-01-25

    Version 00 SHREDI is a shielding code system which executes removal-diffusion computations for bi-dimensional shields in r-z or x-y geometries. It may also deal with monodimensional problems (infinitely high cylinders or slabs). MESYST can simulate 3D tracer dispersion in the atmosphere. Three programs are part of this system: CRE_TOPO prepares the terrain data for MESYST. NOABL calculates three-dimensional free divergence windfields over complex terrain. PAS computes tracer concentrations and depositions on a given domain. Themore » purpose of this work is to develop a reliable simulation tool for pollutant atmospheric dispersion, which gives a realistic approach and allows one to compute the pollutant concentrations over complex terrains with good accuracy. The factional brownian model, which furnishes more accurate concentration values, is introduced to calculate pollutant atmospheric dispersion. The model was validated on SIESTA international experiments.« less

  9. Multiphysics Simulation in the Development of Thermoelectric Energy Harvesting Systems

    NASA Astrophysics Data System (ADS)

    Nesarajah, Marco; Frey, Georg

    2016-03-01

    This contribution presents a model-based development process for thermoelectric energy harvesting systems. Such systems convert thermal energy into electrical energy and produce enough energy to supply low-power devices. Realizations require three main challenges to be solved: to guarantee optimal thermal connection of the thermoelectric generators, to find a good design for the energy harvesting system, and to find an optimal electrical connection. Therefore, a development process is presented here. The process is divided into different steps and supports the developer in finding an optimal thermoelectric energy harvesting system for a given heat source and given objectives (technical and economical). During the process, several steps are supported by simulation models. Based on developed model libraries in Modelica®/Dymola®, thermal, thermoelectrical, electrical, and control components can be modeled, integrated into different variants, and verified step by step before the system is physically built and finally validated. The process is illustrated by an example through all the steps.

  10. A Large Motion Suspension System for Simulation of Orbital Deployment

    NASA Technical Reports Server (NTRS)

    Straube, T. M.; Peterson, L. D.

    1994-01-01

    This paper describes the design and implementation of a vertical degree of freedom suspension system which provides a constant force off-load condition to counter gravity over large displacements. By accommodating motions up to one meter for structures weighing up to 100 pounds, the system is useful for experiments which simulate the on-orbit deployment of spacecraft components. A unique aspect of this system is the combination of a large stroke passive off-load device augmented by electromotive torque actuated force feedback. The active force feedback has the effect of reducing breakaway friction by an order of magnitude over the passive system alone. The paper describes the development of the suspension hardware and the feedback control algorithm. Experiments were performed to verify the suspensions system's ability to provide a gravity off-load as well as its effect on the modal characteristics of a test article.

  11. Simulation of a Production Facility with an Automated Transport System

    SciTech Connect

    ABRAMCZYK, GLENN

    2004-04-07

    A model was needed to assess material throughput and validate the conceptual design of a production facility, including equipment lists and layout. The initial desire was to use a commercially available discrete event simulation package. However, the available software was found to be too limited in capability. Database interface software was used to develop autonomous intelligent manufacturing workstations and material transporters. The initial Extend model used to assess material throughput and develop equipment lists for the preconceptual design effort was upgraded with software add-ons from Simulation Dynamics, Inc. (SDI). Use of the SDI database interface allowed the upgraded model to include: 1. a material mass balance at any level of detail required by the user, and 2. a transport system model that includes all transport system movements, time delays, and transfers between systems. This model will assist in evaluating transport system capacity, sensitive time delays in the system, and optimal operating strategies. An additional benefit of using the SDI database interface is dramatically improved run time performance. This allows significantly more runs to be completed to provide better statistics for overall plant performance. The model has all system and process parameters entered into sub-component accessible tables. All information for the manufactured items and process data is automatically generated and written to the database. The standard software is used for the movement of manufactured items between workstations, and for sequence and timing functions. Use of the database permits almost unlimited process control and data collection with an insignificant effect on run time.

  12. Langley advanced real-time simulation (ARTS) system

    NASA Technical Reports Server (NTRS)

    Crawford, Daniel J.; Cleveland, Jeff I., II

    1988-01-01

    A system of high-speed digital data networks was developed and installed to support real-time flight simulation at the NASA Langley Research Center. This system, unlike its predecessor, employs intelligence at each network node and uses distributed 10-V signal conversion equipment rather than centralized 100-V equipment. A network switch, which replaces an elaborate system of patch panels, allows the researcher to construct a customized network from the 25 available simulation sites by invoking a computer control statement. The intent of this paper is to provide a coherent functional description of the system. This development required many significant innovations to enhance performance and functionality such as the real-time clock, the network switch, and improvements to the CAMAC network to increase both distances to sites and data rates. The system has been successfully tested at a usable data rate of 24 M. The fiber optic lines allow distances of approximately 1.5 miles from switch to site. Unlike other local networks, CAMAC does not buffer data in blocks. Therefore, time delays in the network are kept below 10 microsec total. This system underwent months of testing and was put into full service in July 1987.

  13. Effectively design and simulate thermosyphon reboiler systems: Part 2

    SciTech Connect

    Martin, G.R.; Sloley, A.W.

    1995-07-01

    Thermosyphon reboilers provide a simple, low-maintenance design for distillation tower reboiler systems. With an understanding of all the factors involved, thermosyphon designs should be more reliable than most other reboiler systems due to an absence of moving parts (pumps) in the process circulation loop. Design of true thermosyphon exchangers requires an intimate knowledge of a distillation tower`s heat balance, temperature levels and pressure balance in the reboiler loop. Temperature levels vary strongly with composition gradients depending on the system`s relative volatilities. Case studies of two industrial units demonstrate implications on exchanger design of the correct and incorrect simulation configuration. The two cases compare a low relative-volatility ({alpha}) system (ethylene-ethane splitter) and a high {alpha} system (FCCU deethanizer). Part 1 covered basic thermosyphon design, advantages and disadvantages. Also, simulation requirements, {alpha} impacts and one-heat-source configurations were discussed. Part 2 continues with configurations of two heat sources at the same and difference temperatures. In addition, comparisons are made between the different designs to show an optimum for each case.

  14. CLARREO shortwave observing system simulation experiments of the twenty-first century: Simulator design and implementation

    SciTech Connect

    Feldman, D.R.; Algieri, C.A.; Ong, J.R.; Collins, W.D.

    2011-04-01

    Projected changes in the Earth system will likely be manifested in changes in reflected solar radiation. This paper introduces an operational Observational System Simulation Experiment (OSSE) to calculate the signals of future climate forcings and feedbacks in top-of-atmosphere reflectance spectra. The OSSE combines simulations from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report for the NCAR Community Climate System Model (CCSM) with the MODTRAN radiative transfer code to calculate reflectance spectra for simulations of current and future climatic conditions over the 21st century. The OSSE produces narrowband reflectances and broadband fluxes, the latter of which have been extensively validated against archived CCSM results. The shortwave reflectance spectra contain atmospheric features including signals from water vapor, liquid and ice clouds, and aerosols. The spectra are also strongly influenced by the surface bidirectional reflectance properties of predicted snow and sea ice and the climatological seasonal cycles of vegetation. By comparing and contrasting simulated reflectance spectra based on emissions scenarios with increasing projected and fixed present-day greenhouse gas and aerosol concentrations, we find that prescribed forcings from increases in anthropogenic sulfate and carbonaceous aerosols are detectable and are spatially confined to lower latitudes. Also, changes in the intertropical convergence zone and poleward shifts in the subsidence zones and the storm tracks are all detectable along with large changes in snow cover and sea ice fraction. These findings suggest that the proposed NASA Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission to measure shortwave reflectance spectra may help elucidate climate forcings, responses, and feedbacks.

  15. Parallel methods for dynamic simulation of multiple manipulator systems

    NASA Technical Reports Server (NTRS)

    Mcmillan, Scott; Sadayappan, P.; Orin, David E.

    1993-01-01

    In this paper, efficient dynamic simulation algorithms for a system of m manipulators, cooperating to manipulate a large load, are developed; their performance, using two possible forms of parallelism on a general-purpose parallel computer, is investigated. One form, temporal parallelism, is obtained with the use of parallel numerical integration methods. A speedup of 3.78 on four processors of CRAY Y-MP8 was achieved with a parallel four-point block predictor-corrector method for the simulation of a four manipulator system. These multi-point methods suffer from reduced accuracy, and when comparing these runs with a serial integration method, the speedup can be as low as 1.83 for simulations with the same accuracy. To regain the performance lost due to accuracy problems, a second form of parallelism is employed. Spatial parallelism allows most of the dynamics of each manipulator chain to be computed simultaneously. Used exclusively in the four processor case, this form of parallelism in conjunction with a serial integration method results in a speedup of 3.1 on four processors over the best serial method. In cases where there are either more processors available or fewer chains in the system, the multi-point parallel integration methods are still advantageous despite the reduced accuracy because both forms of parallelism can then combine to generate more parallel tasks and achieve greater effective speedups. This paper also includes results for these cases.

  16. Simulation of an advanced techniques of ion propulsion Rocket system

    NASA Astrophysics Data System (ADS)

    Bakkiyaraj, R.

    2016-07-01

    The ion propulsion rocket system is expected to become popular with the development of Deuterium,Argon gas and Hexagonal shape Magneto hydrodynamic(MHD) techniques because of the stimulation indirectly generated the power from ionization chamber,design of thrust range is 1.2 N with 40 KW of electric power and high efficiency.The proposed work is the study of MHD power generation through ionization level of Deuterium gas and combination of two gaseous ions(Deuterium gas ions + Argon gas ions) at acceleration stage.IPR consists of three parts 1.Hexagonal shape MHD based power generator through ionization chamber 2.ion accelerator 3.Exhaust of Nozzle.Initially the required energy around 1312 KJ/mol is carrying out the purpose of deuterium gas which is changed to ionization level.The ionized Deuterium gas comes out from RF ionization chamber to nozzle through MHD generator with enhanced velocity then after voltage is generated across the two pairs of electrode in MHD.it will produce thrust value with the help of mixing of Deuterium ion and Argon ion at acceleration position.The simulation of the IPR system has been carried out by MATLAB.By comparing the simulation results with the theoretical and previous results,if reaches that the proposed method is achieved of thrust value with 40KW power for simulating the IPR system.

  17. Ultraviolet scene simulation for missile approach warning system testing

    NASA Astrophysics Data System (ADS)

    Giza, Robert H.; Acevedo, Paul A.; Bliss, John D.

    1997-07-01

    Ultraviolet (UV) extensions have been incorporated in the Real-time IR/EO Scene Simulator to support hardware-in-the- loop (HWIL) testing of UV missile warning systems. The UV extensions add capability to model missile plume signatures and off-axis atmospheric scattering in the solar blind UV spectral region (200 - 400 nm). Preliminary testing and validation of the UV rendering algorithms were performed. Simulated UV missile signatures were compared to measured static and free-flight test data. This work was performed to support the test and evaluation of modern missile warning systems at Wright labs Integrated Defensive Avionics Lab. This paper will discuss development of HWIL testing capability for UV missile warning receiver systems. Requirements for real-time UV simulation will be defined and a real-time architecture that addresses these requirements will be discussed. Specifically, the development of real- time UV rendering algorithms to support modeling of atmospherics and backgrounds to the UV solar blind wavelength region will be outlined. Issues regarding implementation of spatial UV scattering effects in a real- time rendering environment will be addressed. Development of the UV sensor model, and its potential implementation in a real-time hardware/software direct injection device will be illustrated. The results of some preliminary validation using laboratory and live firing test data will also be discussed.

  18. SYSTEM PLANNING WITH THE HANFORD WASTE OPERATIONS SIMULATOR

    SciTech Connect

    CRAWFORD TW; CERTA PJ; WELLS MN

    2010-01-14

    At the U. S. Department of Energy's Hanford Site in southeastern Washington State, 216 million liters (57 million gallons) of nuclear waste is currently stored in aging underground tanks, threatening the Columbia River. The River Protection Project (RPP), a fully integrated system of waste storage, retrieval, treatment, and disposal facilities, is in varying stages of design, construction, operation, and future planning. These facilities face many overlapping technical, regulatory, and financial hurdles to achieve site cleanup and closure. Program execution is ongoing, but completion is currently expected to take approximately 40 more years. Strategic planning for the treatment of Hanford tank waste is by nature a multi-faceted, complex and iterative process. To help manage the planning, a report referred to as the RPP System Plan is prepared to provide a basis for aligning the program scope with the cost and schedule, from upper-tier contracts to individual facility operating plans. The Hanford Tank Waste Operations Simulator (HTWOS), a dynamic flowsheet simulation and mass balance computer model, is used to simulate the current planned RPP mission, evaluate the impacts of changes to the mission, and assist in planning near-term facility operations. Development of additional modeling tools, including an operations research model and a cost model, will further improve long-term planning confidence. The most recent RPP System Plan, Revision 4, was published in September 2009.

  19. Simulation of a data archival and distribution system at GSFC

    NASA Technical Reports Server (NTRS)

    Bedet, Jean-Jacques; Bodden, Lee; Dwyer, AL; Hariharan, P. C.; Berbert, John; Kobler, Ben; Pease, Phil

    1993-01-01

    A version-0 of a Data Archive and Distribution System (DADS) is being developed at GSFC to support existing and pre-EOS Earth science datasets and test Earth Observing System Data and Information System (EOSDIS) concepts. The performance of DADS is predicted using a discrete event simulation model. The goals of the simulation were to estimate the amount of disk space needed and the time required to fulfill the DADS requirements for ingestion (14 GB/day) and distribution (48 GB/day). The model has demonstrated that 4 mm and 8 mm stackers can play a critical role in improving the performance of the DADS, since it takes, on average, 3 minutes to manually mount/dismount tapes compared to less than a minute with stackers. With two 4 mm stackers and two 8 mm stackers, and a single operator per shift, the DADS requirements can be met within 16 hours using a total of 9 GB of disk space. When the DADS has no stacker, and the DADS depends entirely on operators to handle the distribution tapes, the simulation has shown that the DADS requirements can still be met within 16 hours, but a minimum of 4 operators per shift were required. The compression/decompression of data sets is very CPU intensive, and relatively slow when performed in software, thereby contributing to an increase in the amount of disk space needed.

  20. An event-based hydrologic simulation model for bioretention systems.

    PubMed

    Roy-Poirier, A; Filion, Y; Champagne, P

    2015-01-01

    Bioretention systems are designed to treat stormwater and provide attenuated drainage between storms. Bioretention has shown great potential at reducing the volume and improving the quality of stormwater. This study introduces the bioretention hydrologic model (BHM), a one-dimensional model that simulates the hydrologic response of a bioretention system over the duration of a storm event. BHM is based on the RECARGA model, but has been adapted for improved accuracy and integration of pollutant transport models. BHM contains four completely-mixed layers and accounts for evapotranspiration, overflow, exfiltration to native soils and underdrain discharge. Model results were evaluated against field data collected over 10 storm events. Simulated flows were particularly sensitive to antecedent water content and drainage parameters of bioretention soils, which were calibrated through an optimisation algorithm. Temporal disparity was observed between simulated and measured flows, which was attributed to preferential flow paths formed within the soil matrix of the field system. Modelling results suggest that soil water storage is the most important short-term hydrologic process in bioretention, with exfiltration having the potential to be significant in native soils with sufficient permeability. PMID:26524443

  1. The infrared and semi-active laser simulation capabilities at the AMSTAR tri-mode system simulation HWIL facility

    NASA Astrophysics Data System (ADS)

    Saylor, Daniel A.; Morris, Joseph; Lowry, William

    2006-05-01

    The Aviation and Missile Research, Engineering and Development Center (AMRDEC), System Simulation and Development Directorate (SS&DD) and Redstone Technical Test Center (RTTC) have teamed together to develop a Hardware-in-the-Loop (HWIL) simulation known as the Advanced Multi-spectral Simulation Test Acceptance Resource (AMSTAR). The simulation facility has the capability to simultaneously produce scenes in three spectral bands. This paper describes Near Infrared (NIR) and Imaging Infrared capabilities of the AMSTAR simulation. Additionally, this paper will described briefly the ability to conduct tests in an environmentally conditioned chamber while the unit-under-test is mounted on the Flight Motion Simulator (FMS).

  2. Evaluating the STORE Reputation System in Multi-Agent Simulations

    NASA Astrophysics Data System (ADS)

    Andrulis, Jonas; Haller, Jochen; Weinhardt, Christof; Karabulut, Yuecel

    In recent global business environments, collaborations among organisations raise an increased demand for swift establishment. Such collaborations are formed between organisations entering Virtual Organizations (VOs), crossing geographic borders and frequently without prior experience of the other partner’s previous performance. In VOs, every participant risks engaging with partners who may exhibit unexpected fraudulent or otherwise untrusted behaviour. In order to cope with this risk, the STochastic REputation system (STORE) was designed to provide swift, automated decision support for selecting partner organisations in the early stages of the VO’s formation. The contribution of this paper first consists of a multi-agent simulation framework design and implementation to evaluate the STORE reputation system. This framework is able to simulate dynamic agent behaviour, agents hereby representing organisations, and to capture the business context of different VO application scenarios. A configuration of agent classes is a powerful tool to obtain not only well or badly performing agents for simulation scenarios, but also agents which are specialized in particular VO application domains or even malicious agents, attacking the VO community. The second contribution comprises of STORE’s evaluation in two simulation scenarios, set in the VO application domains of Collaborative Engineering and Ad-hoc Service provisioning. Besides the ability to clearly distinguish between agents of different classes according to their reputation, the results prove STORE’s ability to take an agent’s dynamic behaviour into account. The simulation results show, that STORE solves the difficult task of selecting the most trustworthy partner for a particular VO application domain from a set of honest agents that are specialized in a wide spread of VO application domains.

  3. Design analysis tracking and data relay satellite simulation system

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The design and development of the equipment necessary to simulate the S-band multiple access link between user spacecraft, the Tracking and Data Relay Satellite, and a ground control terminal are discussed. The core of the S-band multiple access concept is the use of an Adaptive Ground Implemented Phased Array. The array contains thirty channels and provides the multiplexing and demultiplexing equipment required to demonstrate the ground implemented beam forming feature. The system provided will make it possible to demonstrate the performance of a desired user and ten interfering sources attempting to pass data through the multiple access system.

  4. Laminar Flow Control Leading Edge Systems in Simulated Airline Service

    NASA Technical Reports Server (NTRS)

    Wagner, R. D.; Maddalon, D. V.; Fisher, D. F.

    1988-01-01

    Achieving laminar flow on the wings of a commercial transport involves difficult problems associated with the wing leading edge. The NASA Leading Edge Flight Test Program has made major progress toward the solution of these problems. The effectiveness and practicality of candidate laminar flow leading edge systems were proven under representative airline service conditions. This was accomplished in a series of simulated airline service flights by modifying a JetStar aircraft with laminar flow leading edge systems and operating it out of three commercial airports in the United States. The aircraft was operated as an airliner would under actual air traffic conditions, in bad weather, and in insect infested environments.

  5. Human habitat positioning system for NASA's space flight environmental simulator

    NASA Technical Reports Server (NTRS)

    Caldwell, W. F.; Tucker, J.; Keas, P.

    1998-01-01

    Artificial gravity by centrifugation offers an effective countermeasure to the physiologic deconditioning of chronic exposure to microgravity; however, the system requirements of rotational velocity, radius of rotation, and resultant centrifugal acceleration require thorough investigation to ascertain the ideal human-use centrifuge configuration. NASA's Space Flight Environmental Simulator (SFES), a 16-meter (52-foot) diameter, animal-use centrifuge, was recently modified to accommodate human occupancy. This paper describes the SFES Human Habitat Positioning System, the mechanism that facilitates radius of rotation variability and alignment of the centrifuge occupants with the artificial gravity vector.

  6. Mass balances for a biological life support system simulation model

    NASA Technical Reports Server (NTRS)

    Volk, Tyler; Rumel, John D.

    1987-01-01

    Design decisions to aid the development of future space-based biological life support systems (BLSS) can be made with simulation models. Here the biochemical stoichiometry is developed for: (1) protein, carbohydrate, fat, fiber, and lignin production in the edible and inedible parts of plants; (2) food consumption and production of organic solids in urine, feces, and wash water by the humans; and (3) operation of the waste processor. Flux values for all components are derived for a steady-state system with wheat as the sole food source.

  7. Physics Detector Simulation Facility Phase II system software description

    SciTech Connect

    Scipioni, B.; Allen, J.; Chang, C.; Huang, J.; Liu, J.; Mestad, S.; Pan, J.; Marquez, M.; Estep, P.

    1993-05-01

    This paper presents the Physics Detector Simulation Facility (PDSF) Phase II system software. A key element in the design of a distributed computing environment for the PDSF has been the separation and distribution of the major functions. The facility has been designed to support batch and interactive processing, and to incorporate the file and tape storage systems. By distributing these functions, it is often possible to provide higher throughput and resource availability. Similarly, the design is intended to exploit event-level parallelism in an open distributed environment.

  8. Digital simulation and modeling of nonlinear stochastic systems

    SciTech Connect

    Richardson, J M; Rowland, J R

    1981-04-01

    Digitally generated solutions of nonlinear stochastic systems are not unique but depend critically on the numerical integration algorithm used. Some theoretical and practical implications of this dependence are examined. The Ito-Stratonovich controversy concerning the solution of nonlinear stochastic systems is shown to be more than a theoretical debate on maintaining Markov properties as opposed to utilizing the computational rules of ordinary calculus. The theoretical arguments give rise to practical considerations in the formation and solution of discrete models from continuous stochastic systems. Well-known numerical integration algorithms are shown not only to provide different solutions for the same stochastic system but also to correspond to different stochastic integral definitions. These correspondences are proved by considering first and second moments of solutions that result from different integration algorithms and then comparing the moments to those arising from various stochastic integral definitions. This algorithm-dependence of solutions is in sharp contrast to the deterministic and linear stochastic cases in which unique solutions are determined by any convergent numerical algorithm. Consequences of the relationship between stochastic system solutions and simulation procedures are presented for a nonlinear filtering example. Monte Carlo simulations and statistical tests are applied to the example to illustrate the determining role which computational procedures play in generating solutions.

  9. Modeling, simulation, and analysis of optical remote sensing systems

    NASA Technical Reports Server (NTRS)

    Kerekes, John Paul; Landgrebe, David A.

    1989-01-01

    Remote Sensing of the Earth's resources from space-based sensors has evolved in the past 20 years from a scientific experiment to a commonly used technological tool. The scientific applications and engineering aspects of remote sensing systems have been studied extensively. However, most of these studies have been aimed at understanding individual aspects of the remote sensing process while relatively few have studied their interrelations. A motivation for studying these interrelationships has arisen with the advent of highly sophisticated configurable sensors as part of the Earth Observing System (EOS) proposed by NASA for the 1990's. Two approaches to investigating remote sensing systems are developed. In one approach, detailed models of the scene, the sensor, and the processing aspects of the system are implemented in a discrete simulation. This approach is useful in creating simulated images with desired characteristics for use in sensor or processing algorithm development. A less complete, but computationally simpler method based on a parametric model of the system is also developed. In this analytical model the various informational classes are parameterized by their spectral mean vector and covariance matrix. These class statistics are modified by models for the atmosphere, the sensor, and processing algorithms and an estimate made of the resulting classification accuracy among the informational classes. Application of these models is made to the study of the proposed High Resolution Imaging Spectrometer (HRIS). The interrelationships among observational conditions, sensor effects, and processing choices are investigated with several interesting results.

  10. Towards a Comprehensive Computational Simulation System for Turbomachinery

    NASA Technical Reports Server (NTRS)

    Shih, Ming-Hsin

    1994-01-01

    The objective of this work is to develop algorithms associated with a comprehensive computational simulation system for turbomachinery flow fields. This development is accomplished in a modular fashion. These modules includes grid generation, visualization, network, simulation, toolbox, and flow modules. An interactive grid generation module is customized to facilitate the grid generation process associated with complicated turbomachinery configurations. With its user-friendly graphical user interface, the user may interactively manipulate the default settings to obtain a quality grid within a fraction of time that is usually required for building a grid about the same geometry with a general-purpose grid generation code. Non-Uniform Rational B-Spline formulations are utilized in the algorithm to maintain geometry fidelity while redistributing grid points on the solid surfaces. Bezier curve formulation is used to allow interactive construction of inner boundaries. It is also utilized to allow interactive point distribution. Cascade surfaces are transformed from three-dimensional surfaces of revolution into two-dimensional parametric planes for easy manipulation. Such a transformation allows these manipulated plane grids to be mapped to surfaces of revolution by any generatrix definition. A sophisticated visualization module is developed to al-low visualization for both grid and flow solution, steady or unsteady. A network module is built to allow data transferring in the heterogeneous environment. A flow module is integrated into this system, using an existing turbomachinery flow code. A simulation module is developed to combine the network, flow, and visualization module to achieve near real-time flow simulation about turbomachinery geometries. A toolbox module is developed to support the overall task. A batch version of the grid generation module is developed to allow portability and has been extended to allow dynamic grid generation for pitch changing

  11. An intelligent simulation system for earthquake disaster assessment

    NASA Astrophysics Data System (ADS)

    Tang, Aiping; Wen, Aihua

    2009-05-01

    This paper presents an intelligent simulation system for an earthquake disaster assessment system based on a development platform of a Geographic Information System (GIS) and Artificial Intelligence (AI). This system is designed to identify the weakness of the structure and infrastructure system in pre-earthquake conditions, quickly assess earthquake damage and make an intelligent emergency response for the public and government during the earthquake and post-earthquake. The system includes the following functions: intelligent seismic hazard assessment, earthquake damage and loss evaluation, optimizing emergency response and post-earthquake recovering plan. The principle, design criteria, structure, functions and test results of this system are described in this paper. Based on its functional characteristics, this system is composed of four parts: an information database, analytical modules, an intelligent decision-making sub-system and a friendly user interface. There are 132 coverages and 78 analytical modules included in the information database and analytical modules. With this system, seismic disaster mitigation strategies can be verified during a pre-earthquake, and be executed at the time of an earthquake and post-earthquake; the earthquake resisting capacities for an entire city and all of its communities can be greatly enhanced. To check its reliability and its efficiency, this system has been tested based on a scenario earthquake event in one city, and the related results have also been given in this paper. At the present, this system has been installed and used in Daqing City, China. After running for almost 10 years, this system has successfully been used in rehearsing of seismic disaster mitigation and post-earthquake emergency response. Simultaneously, an optimizing aseismic retrofitting plan in Daqing City has been executed based on results from this system.

  12. Description of waste pretreatment and interfacing systems dynamic simulation model

    SciTech Connect

    Garbrick, D.J.; Zimmerman, B.D.

    1995-05-01

    The Waste Pretreatment and Interfacing Systems Dynamic Simulation Model was created to investigate the required pretreatment facility processing rates for both high level and low level waste so that the vitrification of tank waste can be completed according to the milestones defined in the Tri-Party Agreement (TPA). In order to achieve this objective, the processes upstream and downstream of the pretreatment facilities must also be included. The simulation model starts with retrieval of tank waste and ends with vitrification for both low level and high level wastes. This report describes the results of three simulation cases: one based on suggested average facility processing rates, one with facility rates determined so that approximately 6 new DSTs are required, and one with facility rates determined so that approximately no new DSTs are required. It appears, based on the simulation results, that reasonable facility processing rates can be selected so that no new DSTs are required by the TWRS program. However, this conclusion must be viewed with respect to the modeling assumptions, described in detail in the report. Also included in the report, in an appendix, are results of two sensitivity cases: one with glass plant water recycle steams recycled versus not recycled, and one employing the TPA SST retrieval schedule versus a more uniform SST retrieval schedule. Both recycling and retrieval schedule appear to have a significant impact on overall tank usage.

  13. Synthesis of recurrent neural networks for dynamical system simulation.

    PubMed

    Trischler, Adam P; D'Eleuterio, Gabriele M T

    2016-08-01

    We review several of the most widely used techniques for training recurrent neural networks to approximate dynamical systems, then describe a novel algorithm for this task. The algorithm is based on an earlier theoretical result that guarantees the quality of the network approximation. We show that a feedforward neural network can be trained on the vector-field representation of a given dynamical system using backpropagation, then recast it as a recurrent network that replicates the original system's dynamics. After detailing this algorithm and its relation to earlier approaches, we present numerical examples that demonstrate its capabilities. One of the distinguishing features of our approach is that both the original dynamical systems and the recurrent networks that simulate them operate in continuous time.

  14. Simulating fail-stop in asynchronous distributed systems

    NASA Technical Reports Server (NTRS)

    Sabel, Laura; Marzullo, Keith

    1994-01-01

    The fail-stop failure model appears frequently in the distributed systems literature. However, in an asynchronous distributed system, the fail-stop model cannot be implemented. In particular, it is impossible to reliably detect crash failures in an asynchronous system. In this paper, we show that it is possible to specify and implement a failure model that is indistinguishable from the fail-stop model from the point of view of any process within an asynchronous system. We give necessary conditions for a failure model to be indistinguishable from the fail-stop model, and derive lower bounds on the amount of process replication needed to implement such a failure model. We present a simple one-round protocol for implementing one such failure model, which we call simulated fail-stop.

  15. Simulating mesoscopic reaction-diffusion systems using the Gillespie algorithm

    SciTech Connect

    Bernstein, David

    2004-12-12

    We examine an application of the Gillespie algorithm to simulating spatially inhomogeneous reaction-diffusion systems in mesoscopic volumes such as cells and microchambers. The method involves discretizing the chamber into elements and modeling the diffusion of chemical species by the movement of molecules between neighboring elements. These transitions are expressed in the form of a set of reactions which are added to the chemical system. The derivation of the rates of these diffusion reactions is by comparison with a finite volume discretization of the heat equation on an unevenly spaced grid. The diffusion coefficient of each species is allowed to be inhomogeneous in space, including discontinuities. The resulting system is solved by the Gillespie algorithm using the fast direct method. We show that in an appropriate limit the method reproduces exact solutions of the heat equation for a purely diffusive system and the nonlinear reaction-rate equation describing the cubic autocatalytic reaction.

  16. Mass balances for a biological life support system simulation model

    NASA Technical Reports Server (NTRS)

    Volk, Tyler; Rummel, John D.

    1987-01-01

    Design decisions to aid the development of future space based biological life support systems (BLSS) can be made with simulation models. The biochemistry stoichiometry was developed for: (1) protein, carbohydrate, fat, fiber, and lignin production in the edible and inedible parts of plants; (2) food consumption and production of organic solids in urine, feces, and wash water by the humans; and (3) operation of the waste processor. Flux values for all components are derived for a steady state system with wheat as the sole food source. The large scale dynamics of a materially closed (BLSS) computer model is described in a companion paper. An extension of this methodology can explore multifood systems and more complex biochemical dynamics while maintaining whole system closure as a focus.

  17. Piloted Simulation of a Model-Predictive Automated Recovery System

    NASA Technical Reports Server (NTRS)

    Liu, James (Yuan); Litt, Jonathan; Sowers, T. Shane; Owens, A. Karl; Guo, Ten-Huei

    2014-01-01

    This presentation describes a model-predictive automatic recovery system for aircraft on the verge of a loss-of-control situation. The system determines when it must intervene to prevent an imminent accident, resulting from a poor approach. It estimates the altitude loss that would result from a go-around maneuver at the current flight condition. If the loss is projected to violate a minimum altitude threshold, the maneuver is automatically triggered. The system deactivates to allow landing once several criteria are met. Piloted flight simulator evaluation showed the system to provide effective envelope protection during extremely unsafe landing attempts. The results demonstrate how flight and propulsion control can be integrated to recover control of the vehicle automatically and prevent a potential catastrophe.

  18. Simulator for an Accelerator-Driven Subcritical Fissile Solution System

    SciTech Connect

    Klein, Steven Karl; Day, Christy M.; Determan, John C.

    2015-09-14

    LANL has developed a process to generate a progressive family of system models for a fissile solution system. This family includes a dynamic system simulation comprised of coupled nonlinear differential equations describing the time evolution of the system. Neutron kinetics, radiolytic gas generation and transport, and core thermal hydraulics are included in the DSS. Extensions to explicit operation of cooling loops and radiolytic gas handling are embedded in these systems as is a stability model. The DSS may then be converted to an implementation in Visual Studio to provide a design team the ability to rapidly estimate system performance impacts from a variety of design decisions. This provides a method to assist in optimization of the system design. Once design has been generated in some detail the C++ version of the system model may then be implemented in a LabVIEW user interface to evaluate operator controls and instrumentation and operator recognition and response to off-normal events. Taken as a set of system models the DSS, Visual Studio, and LabVIEW progression provides a comprehensive set of design support tools.

  19. A Virtual Engineering Framework for Simulating Advanced Power System

    SciTech Connect

    Mike Bockelie; Dave Swensen; Martin Denison; Stanislav Borodai

    2008-06-18

    In this report is described the work effort performed to provide NETL with VE-Suite based Virtual Engineering software and enhanced equipment models to support NETL's Advanced Process Engineering Co-simulation (APECS) framework for advanced power generation systems. Enhancements to the software framework facilitated an important link between APECS and the virtual engineering capabilities provided by VE-Suite (e.g., equipment and process visualization, information assimilation). Model enhancements focused on improving predictions for the performance of entrained flow coal gasifiers and important auxiliary equipment (e.g., Air Separation Units) used in coal gasification systems. In addition, a Reduced Order Model generation tool and software to provide a coupling between APECS/AspenPlus and the GE GateCycle simulation system were developed. CAPE-Open model interfaces were employed where needed. The improved simulation capability is demonstrated on selected test problems. As part of the project an Advisory Panel was formed to provide guidance on the issues on which to focus the work effort. The Advisory Panel included experts from industry and academics in gasification, CO2 capture issues, process simulation and representatives from technology developers and the electric utility industry. To optimize the benefit to NETL, REI coordinated its efforts with NETL and NETL funded projects at Iowa State University, Carnegie Mellon University and ANSYS/Fluent, Inc. The improved simulation capabilities incorporated into APECS will enable researchers and engineers to better understand the interactions of different equipment components, identify weaknesses and processes needing improvement and thereby allow more efficient, less expensive plants to be developed and brought on-line faster and in a more cost-effective manner. These enhancements to APECS represent an important step toward having a fully integrated environment for performing plant simulation and engineering

  20. Focusing the research agenda for simulation training visual system requirements

    NASA Astrophysics Data System (ADS)

    Lloyd, Charles J.

    2014-06-01

    Advances in the capabilities of the display-related technologies with potential uses in simulation training devices continue to occur at a rapid pace. Simultaneously, ongoing reductions in defense spending stimulate the services to push a higher proportion of training into ground-based simulators to reduce their operational costs. These two trends result in increased customer expectations and desires for more capable training devices, while the money available for these devices is decreasing. Thus, there exists an increasing need to improve the efficiency of the acquisition process and to increase the probability that users get the training devices they need at the lowest practical cost. In support of this need the IDEAS program was initiated in 2010 with the goal of improving display system requirements associated with unmet user needs and expectations and disrupted acquisitions. This paper describes a process of identifying, rating, and selecting the design parameters that should receive research attention. Analyses of existing requirements documents reveal that between 40 and 50 specific design parameters (i.e., resolution, contrast, luminance, field of view, frame rate, etc.) are typically called out for the acquisition of a simulation training display system. Obviously no research effort can address the effects of this many parameters. Thus, we developed a defensible strategy for focusing limited R&D resources on a fraction of these parameters. This strategy encompasses six criteria to identify the parameters most worthy of research attention. Examples based on display design parameters recommended by stakeholders are provided.

  1. Model for simulating scorpion substrate vibration and detection system

    NASA Astrophysics Data System (ADS)

    Sadiq, B. A.; Aibinu, A. M.; Joseph, E.; Salau, H. B.; Salami, M. J. E.

    2013-12-01

    Scorpion stings are vital health issues which requires prompt attention to minimize the pain inflicted on victims and avert death. A possible solution in averting the sting is the capability of detecting its presence earlier before it stings. Scorpion like other arthropods have a specific kind of movement pattern called substrate vibration, which generates a specific signal that is used in recognizing and locating mates and preys. This paper aims at developing an intelligent scorpion detection system using vibration frequency detection technique. A six step model for simulating scorpion substrate vibration and detection has been proposed. The surrounding vibrating signal is acquired and passed through a band pass filter. The resulting signal is model using autoregressive modeling technique. Resulting co-efficients are further analyzed for activity detection. The frequency response of scorpion activities for mating behaviour was simulated, detected analysed using MATLAB environment. The resulting coefficients was also compared and analysed. Results obtained shows that the proposed technique is appropriate for model and simulating scorpion substrate vibration and detection system.

  2. A Data Management System for International Space Station Simulation Tools

    NASA Technical Reports Server (NTRS)

    Betts, Bradley J.; DelMundo, Rommel; Elcott, Sharif; McIntosh, Dawn; Niehaus, Brian; Papasin, Richard; Mah, Robert W.; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Groups associated with the design, operational, and training aspects of the International Space Station make extensive use of modeling and simulation tools. Users of these tools often need to access and manipulate large quantities of data associated with the station, ranging from design documents to wiring diagrams. Retrieving and manipulating this data directly within the simulation and modeling environment can provide substantial benefit to users. An approach for providing these kinds of data management services, including a database schema and class structure, is presented. Implementation details are also provided as a data management system is integrated into the Intelligent Virtual Station, a modeling and simulation tool developed by the NASA Ames Smart Systems Research Laboratory. One use of the Intelligent Virtual Station is generating station-related training procedures in a virtual environment, The data management component allows users to quickly and easily retrieve information related to objects on the station, enhancing their ability to generate accurate procedures. Users can associate new information with objects and have that information stored in a database.

  3. Simulation of Lidar System Performance in Terrestrial Mapping Applications

    NASA Astrophysics Data System (ADS)

    Pack, R. T.; Fullmer, R. R.

    2003-12-01

    Anyone who has used terrestrial lidar data in physical science applications has likely observed both systematic and random errors in datasets. An understanding of the potential sources of error is important when applying post-mission filters that remove errors, artifacts and unwanted features - such as vegetation - from lidar "point-cloud" data sets. System error sources typically include, (1) range error associated with transceiver optoelectronics design and atmospheric transmission characteristics, (2) pointing error associated with scanner dynamics, platform instability and GPS/INS readouts. To better understand and anticipate lidar data phenomenology and quality when designing lidar systems and surveys, simulation software has been developed at Utah State University Center for Advanced Imaging Ladar. The simulation focuses on energy-detection lidars common in commercial airborne mapping applications. It accepts as inputs: laser power, pulse width, wavelength, beam divergence and pulse repetition frequency; optics including aperture, field-of-view, and transmission loss; detector characteristics including focal plane array geometry, quantum efficiency, noise-equivalent power, optical efficiency, optical pass band, noise bandwidth, and readout error; scanner dynamics including bandwidth and damping ratio; GPS/INS errors associated with various instrument grades; environmental parameters including aerosol type, visibility, and solar spectral irradiance; scene parameters including backscatter distribution and reflectivity; and trajectories including position, velocity, and attitude. The simulation is designed to be adaptable to a wide variety of lidar system types, environmental settings, and aircraft trajectories over specific terrain models. It was built in MATLAB/Simulink, a convenient environment for computation and data generation, and has many graphical interfaces. Principally funded by the U.S. Naval Air Warfare Center at China Lake, California, it has been

  4. Feasibility study of sedimentary enhanced geothermal systems using reservoir simulation

    NASA Astrophysics Data System (ADS)

    Cho, Jae Kyoung

    investigated. Especially, water density, viscosity and rock heat capacity play a significant role in reservoir performance. The Permian Lyons formation in the Denver Basin is selected for this preliminary study. Well log data around the area of interest are collected and borehole temperature data are analyzed to estimate the geothermal potential of the target area and it follows that the target formation has a geothermal gradient as high as 72 °C/km. Based on the well log data, hypothetical reservoir simulation models are build and tested to access the hydraulic and thermal performance. It turns out that the target formation is marginally or sub-marginally commercial in terms of its formation conductivity. Therefore, the target formation may require reservoir stimulation for commercially viable power generation. Lastly, reservoir simulation models with average petrophysical properties obtained from the well log analysis of the target formation are built. In order to account for overburden and underburden heat transfer for confined reservoirs, low permeability layers representing shale cap/bed rocks are attached to the top and bottom of the reservoir layers. The dual permeability concept is applied to the reservoir layers to model induced fracture networks by reservoir stimulation. The simulation models are tested by changing fracture conductivity and shape factor. The results show that a balance between hydraulic and thermal performance should be achieved to meet the target flow rate and sustainability of 30 years' uninterrupted operation of geothermal electricity power generation. Ineffective reservoir stimulation could result in failing to create a producing reservoir with appropriate productivity index or causing premature thermal breakthrough or short-circuiting which advances the end of geothermal systems. Therefore, Enhanced Geothermal Systems (EGS) should be engineered to secure producing performance and operational sustainability simultaneously.

  5. A large scale software system for simulation and design optimization of mechanical systems

    NASA Technical Reports Server (NTRS)

    Dopker, Bernhard; Haug, Edward J.

    1989-01-01

    The concept of an advanced integrated, networked simulation and design system is outlined. Such an advanced system can be developed utilizing existing codes without compromising the integrity and functionality of the system. An example has been used to demonstrate the applicability of the concept of the integrated system outlined here. The development of an integrated system can be done incrementally. Initial capabilities can be developed and implemented without having a detailed design of the global system. Only a conceptual global system must exist. For a fully integrated, user friendly design system, further research is needed in the areas of engineering data bases, distributed data bases, and advanced user interface design.

  6. Web-based system for surgical planning and simulation

    NASA Astrophysics Data System (ADS)

    Eldeib, Ayman M.; Ahmed, Mohamed N.; Farag, Aly A.; Sites, C. B.

    1998-10-01

    The growing scientific knowledge and rapid progress in medical imaging techniques has led to an increasing demand for better and more efficient methods of remote access to high-performance computer facilities. This paper introduces a web-based telemedicine project that provides interactive tools for surgical simulation and planning. The presented approach makes use of client-server architecture based on new internet technology where clients use an ordinary web browser to view, send, receive and manipulate patients' medical records while the server uses the supercomputer facility to generate online semi-automatic segmentation, 3D visualization, surgical simulation/planning and neuroendoscopic procedures navigation. The supercomputer (SGI ONYX 1000) is located at the Computer Vision and Image Processing Lab, University of Louisville, Kentucky. This system is under development in cooperation with the Department of Neurological Surgery, Alliant Health Systems, Louisville, Kentucky. The server is connected via a network to the Picture Archiving and Communication System at Alliant Health Systems through a DICOM standard interface that enables authorized clients to access patients' images from different medical modalities.

  7. A framework for industrial systems modeling and simulation

    SciTech Connect

    Macfarlane, J.; Nachnani, S.; Tsai, L.H.; Kaae, P.; Freund, K.; Hoza, M.; Stahlman, E.

    1995-04-01

    To successfully compete in a global market, manufacturing production systems are being forced to reduce time to market and to provide improved responsiveness to changes in market conditions. The organizations that comprise the business links in the production system must constantly make tradeoffs between time and cost in order to achieve a competitive but quick response to consumer demand. Due to the inherent uncertainty of consumer demand, these tradeoffs are, by definition, made with incomplete information and can incur significant financial and competitive risk to the organization. Partnerships between organizations are a mechanism for increasing the information in the decision making process by combining information from the two partners. Partnerships are inherently difficult to implement due to trust issues. A mechanism for investigating and validating the mutual benefit to partnering would be useful in designing and implementing partnerships. This paper describes the development of a software framework for industrial systems modeling and simulation. The framework provides a mechanism for investigating changes to industrial systems in a manner which minimizes the effort and computational power needed to develop focused simulations. The architecture and it`s component parts are described.

  8. Optimal subinterval selection approach for power system transient stability simulation

    SciTech Connect

    Kim, Soobae; Overbye, Thomas J.

    2015-10-21

    Power system transient stability analysis requires an appropriate integration time step to avoid numerical instability as well as to reduce computational demands. For fast system dynamics, which vary more rapidly than what the time step covers, a fraction of the time step, called a subinterval, is used. However, the optimal value of this subinterval is not easily determined because the analysis of the system dynamics might be required. This selection is usually made from engineering experiences, and perhaps trial and error. This paper proposes an optimal subinterval selection approach for power system transient stability analysis, which is based on modal analysis using a single machine infinite bus (SMIB) system. Fast system dynamics are identified with the modal analysis and the SMIB system is used focusing on fast local modes. An appropriate subinterval time step from the proposed approach can reduce computational burden and achieve accurate simulation responses as well. As a result, the performance of the proposed method is demonstrated with the GSO 37-bus system.

  9. Optimal subinterval selection approach for power system transient stability simulation

    DOE PAGES

    Kim, Soobae; Overbye, Thomas J.

    2015-10-21

    Power system transient stability analysis requires an appropriate integration time step to avoid numerical instability as well as to reduce computational demands. For fast system dynamics, which vary more rapidly than what the time step covers, a fraction of the time step, called a subinterval, is used. However, the optimal value of this subinterval is not easily determined because the analysis of the system dynamics might be required. This selection is usually made from engineering experiences, and perhaps trial and error. This paper proposes an optimal subinterval selection approach for power system transient stability analysis, which is based on modalmore » analysis using a single machine infinite bus (SMIB) system. Fast system dynamics are identified with the modal analysis and the SMIB system is used focusing on fast local modes. An appropriate subinterval time step from the proposed approach can reduce computational burden and achieve accurate simulation responses as well. As a result, the performance of the proposed method is demonstrated with the GSO 37-bus system.« less

  10. Simulating forest landscape disturbances as coupled human and natural systems

    USGS Publications Warehouse

    Wimberly, Michael; Sohl, Terry L.; Liu, Zhihua; Lamsal, Aashis

    2015-01-01

    Anthropogenic disturbances resulting from human land use affect forest landscapes over a range of spatial and temporal scales, with diverse influences on vegetation patterns and dynamics. These processes fall within the scope of the coupled human and natural systems (CHANS) concept, which has emerged as an important framework for understanding the reciprocal interactions and feedbacks that connect human activities and ecosystem responses. Spatial simulation modeling of forest landscape change is an important technique for exploring the dynamics of CHANS over large areas and long time periods. Landscape models for simulating interactions between human activities and forest landscape dynamics can be grouped into two main categories. Forest landscape models (FLMs) focus on landscapes where forests are the dominant land cover and simulate succession and natural disturbances along with forest management activities. In contrast, land change models (LCMs) simulate mosaics of different land cover and land use classes that include forests in addition to other land uses such as developed areas and agricultural lands. There are also several examples of coupled models that combine elements of FLMs and LCMs. These integrated models are particularly useful for simulating human–natural interactions in landscapes where human settlement and agriculture are expanding into forested areas. Despite important differences in spatial scale and disciplinary scope, FLMs and LCMs have many commonalities in conceptual design and technical implementation that can facilitate continued integration. The ultimate goal will be to implement forest landscape disturbance modeling in a CHANS framework that recognizes the contextual effects of regional land use and other human activities on the forest ecosystem while capturing the reciprocal influences of forests and their disturbances on the broader land use mosaic.

  11. Enhanced vision systems: results of simulation and operational tests

    NASA Astrophysics Data System (ADS)

    Hecker, Peter; Doehler, Hans-Ullrich

    1998-07-01

    Today's aircrews have to handle more and more complex situations. Most critical tasks in the field of civil aviation are landing approaches and taxiing. Especially under bad weather conditions the crew has to handle a tremendous workload. Therefore DLR's Institute of Flight Guidance has developed a concept for an enhanced vision system (EVS), which increases performance and safety of the aircrew and provides comprehensive situational awareness. In previous contributions some elements of this concept have been presented, i.e. the 'Simulation of Imaging Radar for Obstacle Detection and Enhanced Vision' by Doehler and Bollmeyer 1996. Now the presented paper gives an overview about the DLR's enhanced vision concept and research approach, which consists of two main components: simulation and experimental evaluation. In a first step the simulational environment for enhanced vision research with a pilot-in-the-loop is introduced. An existing fixed base flight simulator is supplemented by real-time simulations of imaging sensors, i.e. imaging radar and infrared. By applying methods of data fusion an enhanced vision display is generated combining different levels of information, such as terrain model data, processed images acquired by sensors, aircraft state vectors and data transmitted via datalink. The second part of this contribution presents some experimental results. In cooperation with Daimler Benz Aerospace Sensorsystems Ulm, a test van and a test aircraft were equipped with a prototype of an imaging millimeter wave radar. This sophisticated HiVision Radar is up to now one of the most promising sensors for all weather operations. Images acquired by this sensor are shown as well as results of data fusion processes based on digital terrain models. The contribution is concluded by a short video presentation.

  12. USSOUTHCOM Counterdrug Modeling and Simulation System (CMASS) report

    SciTech Connect

    Not Available

    1993-03-31

    USSOUTHCOM, in conjunction with Los Alamos National Labs (LANL), is in its second year of development of CMASS (Counterdrug Modeling and Simulation System). The purpose of this project is to provide an opportunity for the multiple agencies involved in the war on drugs to cooperate to simulate the various activities that must be coordinated and performed to meet the mission. LANL is providing development of computer-based support data and models to assist in gaming and strategies. Other contractors provide technology and program management support. Section 1 of this report provides observations and recommendations based on: numerous conversations with representatives from the various participating agencies and services; observation of two iterations of wargames held at the Joint Warfare Center, Hurlburt Field, FL; and reading and reviewing briefings and literature as provided by the program management office and by various agencies. Section 2 compares and contrasts two delivery media currently available in the Department of Defense.

  13. USSOUTHCOM Counterdrug Modeling and Simulation System (CMASS) report. Final report

    SciTech Connect

    Not Available

    1993-03-31

    USSOUTHCOM, in conjunction with Los Alamos National Labs (LANL), is in its second year of development of CMASS (Counterdrug Modeling and Simulation System). The purpose of this project is to provide an opportunity for the multiple agencies involved in the war on drugs to cooperate to simulate the various activities that must be coordinated and performed to meet the mission. LANL is providing development of computer-based support data and models to assist in gaming and strategies. Other contractors provide technology and program management support. Section 1 of this report provides observations and recommendations based on: numerous conversations with representatives from the various participating agencies and services; observation of two iterations of wargames held at the Joint Warfare Center, Hurlburt Field, FL; and reading and reviewing briefings and literature as provided by the program management office and by various agencies. Section 2 compares and contrasts two delivery media currently available in the Department of Defense.

  14. Practical Entanglement Estimation for Spin-System Quantum Simulators.

    PubMed

    Marty, O; Cramer, M; Plenio, M B

    2016-03-11

    We present practical methods to measure entanglement for quantum simulators that can be realized with trapped ions, cold atoms, and superconducting qubits. Focusing on long- and short-range Ising-type Hamiltonians, we introduce schemes that are applicable under realistic experimental conditions including mixedness due to, e.g., noise or temperature. In particular, we identify a single observable whose expectation value serves as a lower bound to entanglement and that may be obtained by a simple quantum circuit. As such circuits are not (yet) available for every platform, we investigate the performance of routinely measured observables as quantitative entanglement witnesses. Possible applications include experimental studies of entanglement scaling in critical systems and the reliable benchmarking of quantum simulators.

  15. ENTROPY PRODUCTION IN COLLISIONLESS SYSTEMS. III. RESULTS FROM SIMULATIONS

    SciTech Connect

    Barnes, Eric I.; Egerer, Colin P. E-mail: egerer.coli@uwlax.edu

    2015-05-20

    The equilibria formed by the self-gravitating, collisionless collapse of simple initial conditions have been investigated for decades. We present the results of our attempts to describe the equilibria formed in N-body simulations using thermodynamically motivated models. Previous work has suggested that it is possible to define distribution functions for such systems that describe maximum entropy states. These distribution functions are used to create radial density and velocity distributions for comparison to those from simulations. A wide variety of N-body code conditions are used to reduce the chance that results are biased by numerical issues. We find that a subset of initial conditions studied lead to equilibria that can be accurately described by these models, and that direct calculation of the entropy shows maximum values being achieved.

  16. Using geographic information systems to simulate patient access areas.

    PubMed

    Doi, Shunsuke; Inoue, Takashi; Ide, Hiroo; Nakamura, Toshihito; Fujita, Shinsuke; Suzuki, Takahiro; Takabayashi, Katsuhiko

    2014-01-01

    We constructed a simulation model with a geographic information system (GIS) to predict the future shortage of beds in the Tokyo Metropolitan Area. With a grid square method, we calculated patient numbers for every 500 square meters of the Tokyo Metropolitan Area until 2040 and estimated whether those in need could be admitted to hospitals within an hour's drive from their homes. The simulation demonstrates that after 2025 many patients may not be able to find hospitals within this time framework. The situation will be especially serious in the center of Tokyo and along the railway lines, where many senior citizens reside. We can now apply this innovative GIS method in many fields and especially for the precise estimation of future demands for and supply of medical assistance.

  17. Evaluating System Parameters on a Dragonfly using Simulation and Visualization

    SciTech Connect

    Bhatele, Abhinav; Jain, Nikhil; Livnat, Yarden; Pascucci, Valerio; Bremer, Peer-Timo

    2015-04-24

    The dragon y topology is becoming a popular choice for build- ing high-radix, low-diameter networks with high-bandwidth links. Even with a powerful network, preliminary experi- ments on Edison at NERSC have shown that for communica- tion heavy applications, job interference and thus presumably job placement remains an important factor. In this paper, we explore the e ects of job placement, job sizes, parallel workloads and network con gurations on network through- put to better understand inter-job interference. We use a simulation tool called Damsel y to model the network be- havior of Edison and study the impact of various system parameters on network throughput. Parallel workloads based on ve representative communication patters are used and the simulation studies on up to 131,072 cores are aided by a new visualization of the dragon y network.

  18. Numerical simulations of a diode laser BPH treatment system

    SciTech Connect

    Esch, V; London, R A; Papademetriou, S

    1999-02-23

    Numerical simulations are presented of the laser-tissue interaction of a diode laser system for treating benign prostate hyperplasia. The numerical model includes laser light transport, heat transport, cooling due to blood perfusion, thermal tissue damage, and enthalpy of tissue damage. Comparisons of the simulation results to clinical data are given. We report that a reasonable variation from a standard set of input data produces heating times which match those measured in the clinical trials. A general trend of decreasing damage volume with increasing heating time is described. We suggest that the patient-to- patient variability seen in the data can be explained by differences in fundamental biophysical properties such as the optical coefficients. Further work is identified, including the measurement and input to the model of several specific data parameters such as optical coefficients, blood perfusion cooling rate, and coagulation rates.

  19. A system simulation development project: Leveraging resources through partnerships

    NASA Technical Reports Server (NTRS)

    Drummond, Colin K.; Owen, A. Karl; Davis, Milt W.

    1995-01-01

    Partnerships between government agencies are an intellectually attractive method of conducting scientific research; the goal is to establish mutually beneficial participant roles for technology exchange that ultimately pays-off in a stronger R&D program for each partner. Anticipated and current aerospace research budgetary pressures through the 90's provide additional impetus for Government research agencies to candidly assess their R&D for those simulation activities no longer unique enough to warrant 'going it alone,' or for those elements where partnerships or teams can offset development costs. This paper describes a specific inter-agency system simulation activity that leverages the development cost of mutually beneficial R&D. While the direct positive influence of partnerships on complex technology developments is our main thesis, we also address on-going teaming issues and hope to impart to the reader the immense indirect (sometimes immeasurable) benefits that meaningful interagency partnerships can produce.

  20. Numerical Simulation of HIWC Conditions with the Terminal Area Simulation System

    NASA Technical Reports Server (NTRS)

    Proctor, Fred H.; Switzer, George F.

    2016-01-01

    Three-dimensional, numerical simulation of a mesoconvective system is conducted in order to better understand conditions associated with High Ice Water Content (HIWC) and its threat to aviation safety. Although peak local values of ice water content may occur early in the storm lifetime, large areas of high concentrations expand with time and persist even when the storm tops begin to warm. The storm canopy which contains HIWC, has low radar reflectivity factor and is fed by an ensemble of regenerating thermal pulses.

  1. Designing power system simulators for the smart grid: combining controls, communications, and electro-mechanical dynamics

    SciTech Connect

    Nutaro, James J

    2011-01-01

    Open source software has a leading role in research on simulation technology for electrical power systems. Research simulators demonstrate new features for which there is nascent but growing demand not yet provided for by commercial simulators. Of particular interest is the inclusion of models of software-intensive and communication-intensive controls in simulations of power system transients. This paper describes two features of the ORNL power system simulator that help it meet this need. First is its use of discrete event simulation for all aspects of the model: control, communication, and electro-mechanical dynamics. Second is an interoperability interface that enables the ORNL power system simulator to be integrated with existing, discrete event simulators of digital communication systems. The paper concludes with a brief discussion of how these aspects of the ORNL power system simulator might be inserted into production-grade simulation tools.

  2. Modeling and simulation of PCM-enhanced facade systems

    NASA Astrophysics Data System (ADS)

    Al-Saadi, Saleh Nasser

    Building facade contributes to the overall architectural aesthetic but can be utilized for heat storage when proper systems are incorporated. Latent heat storage such as using a phase change material (PCM) gains growing attentions recently due to its ability of storing significant thermal energy within a small volume, making it one of most promising technologies for developing energy efficient buildings. This research is focused on modeling and simulation of PCM when integrated into advanced facade systems. The study first reviews the different mathematical modeling methods generally used for PCM's simulations. It categorizes the PCM's numerical models that are implemented for standalone facade systems. The study then evaluates the PCM's models that are integrated into whole building simulation tools such as EnergyPlus, TRNSYS, ESPr etc. It is revealed that the heat capacity method is mostly used in programs, despite its limitations on time and spatial resolutions. Therefore, alternative numerical models are investigated to overcome the above constrains and limitations in current PCM's simulation practice. Eight potential computational models based on a fully implicit finite volume method are developed in MATLAB/SIMULINK environment, validated using experimental results from the literature and verified against well-known building simulation programs. A linearized enthalpy method with hybrid correction scheme is proposed and validated in this work as an improvement to the existing numerical schemes for implementation into building simulation tools. Through sensitivity analysis achieved by varying the PCM thermal properties, the models have been analyzed for their computational efficiency and prediction accuracy. Some models are found sensitive to melting range of PCM, for example heat capacity method, but less sensitive to the variations of latent heat. Among the correction schemes, the non-iterative scheme is inaccurate due to the significant temperature spikes

  3. Code System for Reactor Physics and Fuel Cycle Simulation.

    1999-04-21

    Version 00 VSOP94 (Very Superior Old Programs) is a system of codes linked together for the simulation of reactor life histories. It comprises neutron cross section libraries and processing routines, repeated neutron spectrum evaluation, 2-D diffusion calculation based on neutron flux synthesis with depletion and shut-down features, in-core and out-of-pile fuel management, fuel cycle cost analysis, and thermal hydraulics (at present restricted to Pebble Bed HTRs). Various techniques have been employed to accelerate the iterativemore » processes and to optimize the internal data transfer. The code system has been used extensively for comparison studies of reactors, their fuel cycles, and related detailed features. In addition to its use in research and development work for the High Temperature Reactor, the system has been applied successfully to Light Water and Heavy Water Reactors.« less

  4. Nuclear Engine System Simulation (NESS) version 2.0

    NASA Technical Reports Server (NTRS)

    Pelaccio, Dennis G.; Scheil, Christine M.; Petrosky, Lyman J.

    1993-01-01

    The topics are presented in viewgraph form and include the following; nuclear thermal propulsion (NTP) engine system analysis program development; nuclear thermal propulsion engine analysis capability requirements; team resources used to support NESS development; expanded liquid engine simulations (ELES) computer model; ELES verification examples; NESS program development evolution; past NTP ELES analysis code modifications and verifications; general NTP engine system features modeled by NESS; representative NTP expander, gas generator, and bleed engine system cycles modeled by NESS; NESS program overview; NESS program flow logic; enabler (NERVA type) nuclear thermal rocket engine; prismatic fuel elements and supports; reactor fuel and support element parameters; reactor parameters as a function of thrust level; internal shield sizing; and reactor thermal model.

  5. Hybrid2: The hybrid power system simulation model

    SciTech Connect

    Baring-Gould, E I; Green, H J; van Dijk, V A.P.; Manwell, J F

    1996-07-01

    There is a large-scale need and desire for energy in remote communities, especially in the developing world; however the lack of a user friendly, flexible performance prediction model for hybrid power systems incorporating renewables hindered the analysis of hybrids (including wind turbines, PV, diesel generators, AC/DC energy storage) as options to conventional solutions. A user friendly model was needed with the versatility to simulate the many system locations, widely varying hardware configurations, and differing control options for potential hybrid power systems. To meet these ends, NREL and U. Mass. researchers developed the Hybrid2 software. This paper provides an overview of the capabilities, features, and functionality of the Hybrid2 code, discusses its validation and future plans. Model availability and technical support provided to Hybrid2 users are also discussed.

  6. Hybrid2 - The hybrid power system simulation model

    SciTech Connect

    Baring-Gould, E.I.; Green, H.J.; Dijk, V.A.P. van; Manwell, J.F.

    1996-12-31

    There is a large-scale need and desire for energy in remote communities, especially in the developing world; however the lack of a user friendly, flexible performance prediction model for hybrid power systems incorporating renewables hindered the analysis of hybrids as options to conventional solutions. A user friendly model was needed with the versatility to simulate the many system locations, widely varying hardware configurations, and differing control options for potential hybrid power systems. To meet these ends, researchers from the National Renewable Energy Laboratory (NREL) and the University of Massachusetts (UMass) developed the Hybrid2 software. This paper provides an overview of the capabilities, features, and functionality of the Hybrid2 code, discusses its validation and future plans. Model availability and technical support provided to Hybrid2 users are also discussed. 12 refs., 3 figs., 4 tabs.

  7. Upgrades to the NESS (Nuclear Engine System Simulation) Code

    NASA Technical Reports Server (NTRS)

    Fittje, James E.

    2007-01-01

    In support of the President's Vision for Space Exploration, the Nuclear Thermal Rocket (NTR) concept is being evaluated as a potential propulsion technology for human expeditions to the moon and Mars. The need for exceptional propulsion system performance in these missions has been documented in numerous studies, and was the primary focus of a considerable effort undertaken during the 1960's and 1970's. The NASA Glenn Research Center is leveraging this past NTR investment in their vehicle concepts and mission analysis studies with the aid of the Nuclear Engine System Simulation (NESS) code. This paper presents the additional capabilities and upgrades made to this code in order to perform higher fidelity NTR propulsion system analysis and design.

  8. Code System for Reactor Physics and Fuel Cycle Simulation.

    SciTech Connect

    TEUCHERT, E.

    1999-04-21

    Version 00 VSOP94 (Very Superior Old Programs) is a system of codes linked together for the simulation of reactor life histories. It comprises neutron cross section libraries and processing routines, repeated neutron spectrum evaluation, 2-D diffusion calculation based on neutron flux synthesis with depletion and shut-down features, in-core and out-of-pile fuel management, fuel cycle cost analysis, and thermal hydraulics (at present restricted to Pebble Bed HTRs). Various techniques have been employed to accelerate the iterative processes and to optimize the internal data transfer. The code system has been used extensively for comparison studies of reactors, their fuel cycles, and related detailed features. In addition to its use in research and development work for the High Temperature Reactor, the system has been applied successfully to Light Water and Heavy Water Reactors.

  9. Simulation of Molecular Transport in Systems Containing Mobile Obstacles.

    PubMed

    Polanowski, Piotr; Sikorski, Andrzej

    2016-08-01

    In this paper, we investigate the movement of molecules in crowded environments with obstacles undergoing Brownian motion by means of extensive Monte Carlo simulations. Our investigations were performed using the dynamic lattice liquid model, which was based on the cooperative movement concept and allowed to mimic systems at high densities where the motion of all elements (obstacles as well as moving particles) were highly correlated. The crowded environments are modeled on a two-dimensional triangular lattice containing obstacles (particles whose mobility was significantly reduced) moving by a Brownian motion. The subdiffusive motion of both elements in the system was analyzed. It was shown that the percolation transition does not exist in such systems in spite of the cooperative character of the particles' motion. The reduction of the obstacle mobility leads to the longer caging of liquid particles by mobile obstacles. PMID:27387448

  10. Visual Simulation of Microalgae Growth in Bioregenerative Life Support System

    NASA Astrophysics Data System (ADS)

    Zhao, Ming

    Bioregenerative life support system is one of the key technologies for future human deep space exploration and long-term space missions. BLSS use biological system as its core unit in combination with other physical and chemical equipments, under the proper control and manipulation by crew to complete a specific task to support life. Food production, waste treatment, oxygen and water regeneration are all conducted by higher plants or microalgae in BLSS, which is the most import characteristic different from other kinds of life support systems. Microalgae is light autotrophic micro-organisms, light undoubtedly is the most import factor which limits its growth and reproduction. Increasing or decreasing the light intensity changes the growth rate of microalgae, and then regulates the concentration of oxygen and carbon dioxide in the system. In this paper, based on the mathematical model of microalgae which grew under the different light intensity, three-dimensional visualization model was built and realized through using 3ds max, Virtools and some other three dimensional software, in order to display its change and impacting on oxygen and carbon dioxide intuitively. We changed its model structure and parameters, such as establishing closed-loop control system, light intensity, temperature and Nutrient fluid’s velocity and so on, carried out computer virtual simulation, and observed dynamic change of system with the aim of providing visualization support for system research.

  11. Enhancing Complex System Performance Using Discrete-Event Simulation

    SciTech Connect

    Allgood, Glenn O; Olama, Mohammed M; Lake, Joe E

    2010-01-01

    In this paper, we utilize discrete-event simulation (DES) merged with human factors analysis to provide the venue within which the separation and deconfliction of the system/human operating principles can occur. A concrete example is presented to illustrate the performance enhancement gains for an aviation cargo flow and security inspection system achieved through the development and use of a process DES. The overall performance of the system is computed, analyzed, and optimized for the different system dynamics. Various performance measures are considered such as system capacity, residual capacity, and total number of pallets waiting for inspection in the queue. These metrics are performance indicators of the system's ability to service current needs and respond to additional requests. We studied and analyzed different scenarios by changing various model parameters such as the number of pieces per pallet ratio, number of inspectors and cargo handling personnel, number of forklifts, number and types of detection systems, inspection modality distribution, alarm rate, and cargo closeout time. The increased physical understanding resulting from execution of the queuing model utilizing these vetted performance measures identified effective ways to meet inspection requirements while maintaining or reducing overall operational cost and eliminating any shipping delays associated with any proposed changes in inspection requirements. With this understanding effective operational strategies can be developed to optimally use personnel while still maintaining plant efficiency, reducing process interruptions, and holding or reducing costs.

  12. Modeling and simulation of a hybrid ship power system

    NASA Astrophysics Data System (ADS)

    Doktorcik, Christopher J.

    2011-12-01

    Optimizing the performance of naval ship power systems requires integrated design and coordination of the respective subsystems (sources, converters, and loads). A significant challenge in the system-level integration is solving the Power Management Control Problem (PMCP). The PMCP entails deciding on subsystem power usages for achieving a trade-off between the error in tracking a desired position/velocity profile, minimizing fuel consumption, and ensuring stable system operation, while at the same time meeting performance limitations of each subsystem. As such, the PMCP naturally arises at a supervisory level of a ship's operation. In this research, several critical steps toward the solution of the PMCP for surface ships have been undertaken. First, new behavioral models have been developed for gas turbine engines, wound rotor synchronous machines, DC super-capacitors, induction machines, and ship propulsion systems. Conventional models describe system inputs and outputs in terms of physical variables such as voltage, current, torque, and force. In contrast, the behavioral models developed herein express system inputs and outputs in terms of power whenever possible. Additionally, the models have been configured to form a hybrid system-level power model (HSPM) of a proposed ship electrical architecture. Lastly, several simulation studies have been completed to expose the capabilities and limitations of the HSPM.

  13. Nuclear Engine System Simulation (NESS). Volume 1: Program user's guide

    NASA Technical Reports Server (NTRS)

    Pelaccio, Dennis G.; Scheil, Christine M.; Petrosky, Lyman J.

    1993-01-01

    A Nuclear Thermal Propulsion (NTP) engine system design analysis tool is required to support current and future Space Exploration Initiative (SEI) propulsion and vehicle design studies. Currently available NTP engine design models are those developed during the NERVA program in the 1960's and early 1970's and are highly unique to that design or are modifications of current liquid propulsion system design models. To date, NTP engine-based liquid design models lack integrated design of key NTP engine design features in the areas of reactor, shielding, multi-propellant capability, and multi-redundant pump feed fuel systems. Additionally, since the SEI effort is in the initial development stage, a robust, verified NTP analysis design tool could be of great use to the community. This effort developed an NTP engine system design analysis program (tool), known as the Nuclear Engine System Simulation (NESS) program, to support ongoing and future engine system and stage design study efforts. In this effort, Science Applications International Corporation's (SAIC) NTP version of the Expanded Liquid Engine Simulation (ELES) program was modified extensively to include Westinghouse Electric Corporation's near-term solid-core reactor design model. The ELES program has extensive capability to conduct preliminary system design analysis of liquid rocket systems and vehicles. The program is modular in nature and is versatile in terms of modeling state-of-the-art component and system options as discussed. The Westinghouse reactor design model, which was integrated in the NESS program, is based on the near-term solid-core ENABLER NTP reactor design concept. This program is now capable of accurately modeling (characterizing) a complete near-term solid-core NTP engine system in great detail, for a number of design options, in an efficient manner. The following discussion summarizes the overall analysis methodology, key assumptions, and capabilities associated with the NESS presents an

  14. Understanding disordered systems through numerical simulation and algorithm development

    NASA Astrophysics Data System (ADS)

    Sweeney, Sean Michael

    Disordered systems arise in many physical contexts. Not all matter is uniform, and impurities or heterogeneities can be modeled by fixed random disorder. Numerous complex networks also possess fixed disorder, leading to applications in transportation systems, telecommunications, social networks, and epidemic modeling, to name a few. Due to their random nature and power law critical behavior, disordered systems are difficult to study analytically. Numerical simulation can help overcome this hurdle by allowing for the rapid computation of system states. In order to get precise statistics and extrapolate to the thermodynamic limit, large systems must be studied over many realizations. Thus, innovative algorithm development is essential in order reduce memory or running time requirements of simulations. This thesis presents a review of disordered systems, as well as a thorough study of two particular systems through numerical simulation, algorithm development and optimization, and careful statistical analysis of scaling properties. Chapter 1 provides a thorough overview of disordered systems, the history of their study in the physics community, and the development of techniques used to study them. Topics of quenched disorder, phase transitions, the renormalization group, criticality, and scale invariance are discussed. Several prominent models of disordered systems are also explained. Lastly, analysis techniques used in studying disordered systems are covered. In Chapter 2, minimal spanning trees on critical percolation clusters are studied, motivated in part by an analytic perturbation expansion by Jackson and Read that I check against numerical calculations. This system has a direct mapping to the ground state of the strongly disordered spin glass. We compute the path length fractal dimension of these trees in dimensions d = {2, 3, 4, 5} and find our results to be compatible with the analytic results suggested by Jackson and Read. In Chapter 3, the random bond Ising

  15. Crash simulations of wheelchair-occupant systems in transport.

    PubMed

    Kang, W; Pilkey, W D

    1998-01-01

    A nonlinear multirigid body dynamic computer model has been developed to simulate the dynamic responses of a wheelchair-occupant system in a vehicle during a crash. The occupant, restrained by safety belts, is seated in a wheelchair that is, in turn, tied down in a vehicle. Validated extensively by crash sled tests at three laboratories, this model has been used to predict the responses of wheelchair-occupant systems in various crash environments. To evaluate the crashworthiness of different wheelchair tie-downs, the sensitivity of several design parameters, such as tiedown stiffness, wheel stiffness, and tiedown positions, has been studied using this model, and optimal values of these parameters for the wheelchair-occupant system have been obtained. Moreover, the model has been used to study the sensitivity of crash sled test pulse corridors in an effort to develop a sled test standard. It has been found that an existing ISO corridor allows large variation and should be "tightened." The model was implemented using a version of the multibody dynamic simulator, the Articulated Total Body program. PMID:9505255

  16. Contrast visibility of simulated microcalcifications in full field mammography systems

    NASA Astrophysics Data System (ADS)

    Carton, Ann-Katherine; Bosmans, Hilde; Van Ongeval, Chantal; Souverijns, Geert; Rogge, Frank; Marchal, Guy

    2003-05-01

    We evaluated the visibility of simulated subtle microcalcifications in real digital mammograms acquired with a flat-panel system (GE) and a CR system (Fuji). Ideal templates of microcalcifications were created, based on the attenuation characteristics of subtle microcalcifications from biopsied specimen in magnified images. X-ray transmission coefficients were expressed in Al-equivalent thickness. In this way, the X-ray transmission of a particular lesion could be re-calculated for other X-ray beams, different mammography systems and for different breast thickness. Extra corrections for differences in spatial resolution were based on the pre-sampled MTF. Zero to 10 simulated microcalcifications were randomly distributed in square frames. These software phantoms were then inserted in sets of raw mammograms of the modalities under study. The composed images were compressed, processed and printed as in clinical routine. Two experienced radiologists indicated the locations of the microcalcifications and rated their detection confidence. It is possible to assess the visibility of 'well controlled" microcalcifications in digital clinical mammograms. Microcalcifications were better visible in the CR images than in the flat panel images. This psychophysical method comes close to the radiologists" practice. It allows fpr including processing and visualization in the analysis and was well appreciated by our radiologists.

  17. Linking Microbial Community Structure to Function in Representative Simulated Systems

    PubMed Central

    Marcus, Ian M.; Wilder, Hailey A.; Quazi, Shanin J.

    2013-01-01

    Pathogenic bacteria are generally studied as a single strain under ideal growing conditions, although these conditions are not the norm in the environments in which pathogens typically proliferate. In this investigation, a representative microbial community along with Escherichia coli O157:H7, a model pathogen, was studied in three environments in which such a pathogen could be found: a human colon, a septic tank, and groundwater. Each of these systems was built in the lab in order to retain the physical/chemical and microbial complexity of the environments while maintaining control of the feed into the models. The microbial community in the colon was found to have a high percentage of bacteriodetes and firmicutes, while the septic tank and groundwater systems were composed mostly of proteobacteria. The introduction of E. coli O157:H7 into the simulated systems elicited a shift in the structures and phenotypic cell characteristics of the microbial communities. The fate and transport of the microbial community with E. coli O157:H7 were found to be significantly different from those of E. coli O157:H7 studied as a single isolate, suggesting that the behavior of the organism in the environment was different from that previously conceived. The findings in this study clearly suggest that to gain insight into the fate of pathogens, cells should be grown and analyzed under conditions simulating those of the environment in which the pathogens are present. PMID:23396331

  18. Simulation study of the ROMPS robot control system

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Liu, HUI-I.

    1994-01-01

    This is a report presenting the progress of a research grant funded by NASA for work performed from June 1, 1993 to August 1, 1993. The report deals with the Robot Operated Material Processing System (ROMPS). It presents results of a computer simulation study conducted to investigate the performance of the control systems controlling the azimuth, elevation, and radial axes of the ROMPS and its gripper. Four study cases are conducted. The first case investigates the control of free motion of the three areas. In the second case, the compliant motion in the elevation axis with the wrist compliant device is studied in terms of position accuracy and impact forces. The third case focuses on the behavior of the control system in controlling the robot motion along the radial axis when pulling the pallet out of the rack. In the fourth case, the compliant motion of the gripper grasping a solid object under the effect of the gripper passive compliance is studied in terms of position accuracy and contact forces. For each of the above cases, a set of PIR gains will be selected to optimize the controller performance and computer simulation results will be presented and discussed.

  19. A computer program for simulating geohydrologic systems in three dimensions

    USGS Publications Warehouse

    Posson, D.R.; Hearne, G.A.; Tracy, J.V.; Frenzel, P.F.

    1980-01-01

    This document is directed toward individuals who wish to use a computer program to simulate ground-water flow in three dimensions. The strongly implicit procedure (SIP) numerical method is used to solve the set of simultaneous equations. New data processing techniques and program input and output options are emphasized. The quifer system to be modeled may be heterogeneous and anisotropic, and may include both artesian and water-table conditions. Systems which consist of well defined alternating layers of highly permeable and poorly permeable material may be represented by a sequence of equations for two dimensional flow in each of the highly permeable units. Boundaries where head or flux is user-specified may be irregularly shaped. The program also allows the user to represent streams as limited-source boundaries when the streamflow is small in relation to the hydraulic stress on the system. The data-processing techniques relating to ' cube ' input and output, to swapping of layers, to restarting of simulation, to free-format NAMELIST input, to the details of each sub-routine 's logic, and to the overlay program structure are discussed. The program is capable of processing large models that might overflow computer memories with conventional programs. Detailed instructions for selecting program options, for initializing the data arrays, for defining ' cube ' output lists and maps, and for plotting hydrographs of calculated and observed heads and/or drawdowns are provided. Output may be restricted to those nodes of particular interest, thereby reducing the volumes of printout for modelers, which may be critical when working at remote terminals. ' Cube ' input commands allow the modeler to set aquifer parameters and initialize the model with very few input records. Appendixes provide instructions to compile the program, definitions and cross-references for program variables, summary of the FLECS structured FORTRAN programming language, listings of the FLECS and

  20. Simulation of a synergistic six-post motion system on the flight simulator for advanced aircraft at NASA-Ames

    NASA Technical Reports Server (NTRS)

    Bose, S. C.; Parris, B. L.

    1977-01-01

    Motion system drive philosophy and corresponding real-time software have been developed for the purpose of simulating the characteristics of a typical synergistic Six-Post Motion System (SPMS) on the Flight Simulator for Advanced Aircraft (FSAA) at NASA-Ames which is a non-synergistic motion system. This paper gives a brief description of these two types of motion systems and the general methods of producing motion cues of the FSAA. An actuator extension transformation which allows the simulation of a typical SPMS by appropriate drive washout and variable position limiting is described.