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Sample records for modeling system butsuri

  1. Communication system modeling

    NASA Technical Reports Server (NTRS)

    Holland, L. D.; Walsh, J. R., Jr.; Wetherington, R. D.

    1971-01-01

    This report presents the results of work on communications systems modeling and covers three different areas of modeling. The first of these deals with the modeling of signals in communication systems in the frequency domain and the calculation of spectra for various modulations. These techniques are applied in determining the frequency spectra produced by a unified carrier system, the down-link portion of the Command and Communications System (CCS). The second modeling area covers the modeling of portions of a communication system on a block basis. A detailed analysis and modeling effort based on control theory is presented along with its application to modeling of the automatic frequency control system of an FM transmitter. A third topic discussed is a method for approximate modeling of stiff systems using state variable techniques.

  2. Mathematical circulatory system model

    NASA Technical Reports Server (NTRS)

    Lakin, William D. (Inventor); Stevens, Scott A. (Inventor)

    2010-01-01

    A system and method of modeling a circulatory system including a regulatory mechanism parameter. In one embodiment, a regulatory mechanism parameter in a lumped parameter model is represented as a logistic function. In another embodiment, the circulatory system model includes a compliant vessel, the model having a parameter representing a change in pressure due to contraction of smooth muscles of a wall of the vessel.

  3. Modular Modeling System Model Builder

    SciTech Connect

    McKim, C.S.; Matthews, M.T.

    1996-12-31

    The latest release of the Modular Modeling System (MMS) Model Builder adds still more time-saving features to an already powerful MMS dynamic-simulation tool set. The Model Builder takes advantage of 32-bit architecture within the Microsoft Windows 95/NT{trademark} Operating Systems to better integrate a mature library of power-plant components. In addition, the MMS Library of components can now be modified and extended with a new tool named MMS CompGen{trademark}. The MMS Model Builder allows the user to quickly build a graphical schematic representation for a plant by selecting from a library of predefined power plant components to dynamically simulate their operation. In addition, each component has a calculation subroutine stored in a dynamic-link library (DLL), which facilitates the determination of a steady-state condition and performance of routine calculations for the component. These calculations, termed auto-parameterization, help avoid repetitive and often tedious hand calculations for model initialization. In striving to meet the needs for large models and increase user productivity, the MMS Model Builder has been completely revamped to make power plant model creation and maintainability easier and more efficient.

  4. Modeling of geothermal systems

    SciTech Connect

    Bodvarsson, G.S.; Pruess, K.; Lippmann, M.J.

    1985-03-01

    During the last decade the use of numerical modeling for geothermal resource evaluation has grown significantly, and new modeling approaches have been developed. In this paper we present a summary of the present status in numerical modeling of geothermal systems, emphasizing recent developments. Different modeling approaches are described and their applicability discussed. The various modeling tasks, including natural-state, exploitation, injection, multi-component and subsidence modeling, are illustrated with geothermal field examples. 99 refs., 14 figs.

  5. System Advisor Model

    2010-03-01

    The System Advisor Model (SAM) is a performance and economic model designed to facilitate decision making for people involved in the renewable energy industry, ranging from project managers and engineers to incentive program designers, technology developers, and researchers.

  6. MLS: Airplane system modeling

    NASA Technical Reports Server (NTRS)

    Thompson, A. D.; Stapleton, B. P.; Walen, D. B.; Rieder, P. F.; Moss, D. G.

    1981-01-01

    Analysis, modeling, and simulations were conducted as part of a multiyear investigation of the more important airplane-system-related items of the microwave landing system (MLS). Particular emphasis was placed upon the airplane RF system, including the antenna radiation distribution, the cabling options from the antenna to the receiver, and the overall impact of the airborne system gains and losses upon the direct-path signal structure. In addition, effort was expended toward determining the impact of the MLS upon the airplane flight management system and developing the initial stages of a fast-time MLS automatic control system simulation model. Results ot these studies are presented.

  7. Integrated Workforce Modeling System

    NASA Technical Reports Server (NTRS)

    Moynihan, Gary P.

    2000-01-01

    There are several computer-based systems, currently in various phases of development at KSC, which encompass some component, aspect, or function of workforce modeling. These systems may offer redundant capabilities and/or incompatible interfaces. A systems approach to workforce modeling is necessary in order to identify and better address user requirements. This research has consisted of two primary tasks. Task 1 provided an assessment of existing and proposed KSC workforce modeling systems for their functionality and applicability to the workforce planning function. Task 2 resulted in the development of a proof-of-concept design for a systems approach to workforce modeling. The model incorporates critical aspects of workforce planning, including hires, attrition, and employee development.

  8. Model-Based Systems

    NASA Technical Reports Server (NTRS)

    Frisch, Harold P.

    2007-01-01

    Engineers, who design systems using text specification documents, focus their work upon the completed system to meet Performance, time and budget goals. Consistency and integrity is difficult to maintain within text documents for a single complex system and more difficult to maintain as several systems are combined into higher-level systems, are maintained over decades, and evolve technically and in performance through updates. This system design approach frequently results in major changes during the system integration and test phase, and in time and budget overruns. Engineers who build system specification documents within a model-based systems environment go a step further and aggregate all of the data. They interrelate all of the data to insure consistency and integrity. After the model is constructed, the various system specification documents are prepared, all from the same database. The consistency and integrity of the model is assured, therefore the consistency and integrity of the various specification documents is insured. This article attempts to define model-based systems relative to such an environment. The intent is to expose the complexity of the enabling problem by outlining what is needed, why it is needed and how needs are being addressed by international standards writing teams.

  9. Canister Model, Systems Analysis

    1993-09-29

    This packges provides a computer simulation of a systems model for packaging nuclear waste and spent nuclear fuel in canisters. The canister model calculates overall programmatic cost, number of canisters, and fuel and waste inventories for the Idaho Chemical Processing Plant (other initial conditions can be entered).

  10. Flexible system modeling

    SciTech Connect

    Maragno, M.; Schmid, C.; Schmieg, M.

    1995-04-01

    Stability analysis calculations are typically based on predefined system models, where, in the majority of cases, the well known IEEE definitions for controllers, prime movers, and other associated devices and functions are in use. for planning purposes, this approach might be acceptable, since predefined sets of parameters will allow a favorable and reasonable behavior of the analyzed system to be achieved, thus representing the possibly implementable system behavior. However, this approach is often also applied for system operation analysis purposes, for which typical IEEE models are applicable only in few cases. In quite a number of cases, even manufacturers who perform highly accurate system modeling studies have been asked to deliver block diagrams and parameters according to a list of available IEEE models. Utilities and consultants with an in-depth knowledge and tradition of conducting system operation performance and optimization studies have frequently requested adequate and accurate procedures and tools to tackle this special field of power system analysis appropriately. This need to solve complex operation analysis and special component planning problems has prompted the development of adequate methods and tools at DIgSILENT Systems in cooperation with FICHTNER C.E. This article focuses on various possibilities to approach this problem and to report on the applied strategies and methods. Comprehensive examples are given to demonstrate the capabilities of the implemented procedures.

  11. Critical Infrastructure Modeling System

    2004-10-01

    The Critical Infrastructure Modeling System (CIMS) is a 3D modeling and simulation environment designed to assist users in the analysis of dependencies within individual infrastructure and also interdependencies between multiple infrastructures. Through visual cuing and textual displays, a use can evaluate the effect of system perturbation and identify the emergent patterns that evolve. These patterns include possible outage areas from a loss of power, denial of service or access, and disruption of operations. Method ofmore » Solution: CIMS allows the user to model a system, create an overlay of information, and create 3D representative images to illustrate key infrastructure elements. A geo-referenced scene, satellite, aerial images or technical drawings can be incorporated into the scene. Scenarios of events can be scripted, and the user can also interact during run time to alter system characteristics. CIMS operates as a discrete event simulation engine feeding a 3D visualization.« less

  12. Modeling Sustainable Food Systems

    NASA Astrophysics Data System (ADS)

    Allen, Thomas; Prosperi, Paolo

    2016-05-01

    The processes underlying environmental, economic, and social unsustainability derive in part from the food system. Building sustainable food systems has become a predominating endeavor aiming to redirect our food systems and policies towards better-adjusted goals and improved societal welfare. Food systems are complex social-ecological systems involving multiple interactions between human and natural components. Policy needs to encourage public perception of humanity and nature as interdependent and interacting. The systemic nature of these interdependencies and interactions calls for systems approaches and integrated assessment tools. Identifying and modeling the intrinsic properties of the food system that will ensure its essential outcomes are maintained or enhanced over time and across generations, will help organizations and governmental institutions to track progress towards sustainability, and set policies that encourage positive transformations. This paper proposes a conceptual model that articulates crucial vulnerability and resilience factors to global environmental and socio-economic changes, postulating specific food and nutrition security issues as priority outcomes of food systems. By acknowledging the systemic nature of sustainability, this approach allows consideration of causal factor dynamics. In a stepwise approach, a logical application is schematized for three Mediterranean countries, namely Spain, France, and Italy.

  13. Modeling Sustainable Food Systems.

    PubMed

    Allen, Thomas; Prosperi, Paolo

    2016-05-01

    The processes underlying environmental, economic, and social unsustainability derive in part from the food system. Building sustainable food systems has become a predominating endeavor aiming to redirect our food systems and policies towards better-adjusted goals and improved societal welfare. Food systems are complex social-ecological systems involving multiple interactions between human and natural components. Policy needs to encourage public perception of humanity and nature as interdependent and interacting. The systemic nature of these interdependencies and interactions calls for systems approaches and integrated assessment tools. Identifying and modeling the intrinsic properties of the food system that will ensure its essential outcomes are maintained or enhanced over time and across generations, will help organizations and governmental institutions to track progress towards sustainability, and set policies that encourage positive transformations. This paper proposes a conceptual model that articulates crucial vulnerability and resilience factors to global environmental and socio-economic changes, postulating specific food and nutrition security issues as priority outcomes of food systems. By acknowledging the systemic nature of sustainability, this approach allows consideration of causal factor dynamics. In a stepwise approach, a logical application is schematized for three Mediterranean countries, namely Spain, France, and Italy.

  14. Distributed fuzzy system modeling

    SciTech Connect

    Pedrycz, W.; Chi Fung Lam, P.; Rocha, A.F.

    1995-05-01

    The paper introduces and studies an idea of distributed modeling treating it as a new paradigm of fuzzy system modeling and analysis. This form of modeling is oriented towards developing individual (local) fuzzy models for specific modeling landmarks (expressed as fuzzy sets) and determining the essential logical relationships between these local models. The models themselves are implemented in the form of logic processors being regarded as specialized fuzzy neural networks. The interaction between the processors is developed either in an inhibitory or excitatory way. In more descriptive way, the distributed model can be sought as a collection of fuzzy finite state machines with their individual local first or higher order memories. It is also clarified how the concept of distributed modeling narrows down a gap between purely numerical (quantitative) models and the qualitative ones originated within the realm of Artificial Intelligence. The overall architecture of distributed modeling is discussed along with the detailed learning schemes. The results of extensive simulation experiments are provided as well. 17 refs.

  15. Distributed generation systems model

    SciTech Connect

    Barklund, C.R.

    1994-12-31

    A slide presentation is given on a distributed generation systems model developed at the Idaho National Engineering Laboratory, and its application to a situation within the Idaho Power Company`s service territory. The objectives of the work were to develop a screening model for distributed generation alternatives, to develop a better understanding of distributed generation as a utility resource, and to further INEL`s understanding of utility concerns in implementing technological change.

  16. Climate system modeling program

    SciTech Connect

    1995-12-31

    The Climate System Modeling Project is a component activity of NSF's Climate Modeling, Analysis and Prediction Program, supported by the Atmospheric Sciences Program, Geosciences Directorate. Its objective is to accelerate progress toward reliable prediction of global and regional climate changes in the decades ahead. CSMP operates through workshops, support for post-docs and graduate students and other collaborative activities designed to promote interdisciplinary and strategic work in support of the overall objective (above) and specifically in three areas, (1) Causes of interdecadal variability in the climate system, (2) Interactions of regional climate forcing with global processes, and (3) Scientific needs of climate assessment.

  17. Modeling the earth system

    SciTech Connect

    Ojima, D.

    1992-12-31

    The 1990 Global Change Institute (GCI) on Earth System Modeling is the third of a series organized by the Office for Interdisciplinary Earth Studies to look in depth at particular issues critical to developing a better understanding of the earth system. The 1990 GCI on Earth System Modeling was organized around three themes: defining critical gaps in the knowledge of the earth system, developing simplified working models, and validating comprehensive system models. This book is divided into three sections that reflect these themes. Each section begins with a set of background papers offering a brief tutorial on the subject, followed by working group reports developed during the institute. These reports summarize the joint ideas and recommendations of the participants and bring to bear the interdisciplinary perspective that imbued the institute. Since the conclusion of the 1990 Global Change Institute, research programs, nationally and internationally, have moved forward to implement a number of the recommendations made at the institute, and many of the participants have maintained collegial interactions to develop research projects addressing the needs identified during the two weeks in Snowmass.

  18. Electronic Education System Model.

    ERIC Educational Resources Information Center

    Cloete, Elsabe

    2001-01-01

    Discusses electronic learning efforts and problems in implementing computers in schools. Defines and describes an electronic educational system model that was developed to assist the designers of different electronic learning settings to plan and successfully implement a specific learning situation, with the focus on the individual requirements of…

  19. Modelling resonant planetary systems

    NASA Astrophysics Data System (ADS)

    Emel'yanenko, V.

    2012-09-01

    Many discovered multi-planet systems are in meanmotion resonances. The aim of this work is to study dynamical processes leading to the formation of resonant configurations on the basis of a unified model described earlier [1]. The model includes gravitational interactions of planets and migration of planets due to the presence of a gas disc. For the observed systems 24 Sex, HD 37124, HD 73526, HD 82943, HD 128311, HD 160691, Kepler 9, NN Ser with planets moving in the 2:1 resonance, it is shown that the capture in this resonance occurs at very wide ranges of parameters of both type I and type II migration. Conditions of migration leading to the formation of the resonant systems HD 45364 и HD 200964 (3:2 and 4:3, respectively) are obtained. Formation scenarios are studied for the systems HD 102272, HD 108874, HD 181433, HD 202206 with planets in high order resonances. We discuss also how gravitational interactions of planets and planetesimal discs lead to the breakup of resonant configurations and the formation of systems similar to the 47 UMa system.

  20. NEP systems model

    NASA Astrophysics Data System (ADS)

    George, Jeffrey A.

    A new nuclear electric propulsion (NEP) systems analysis code is discussed. The new code is modular and consists of a driver code and various subsystem models. The code models five different subsystems: (1) reactor/shield; (2) power conversion; (3) heat rejection; (4) power management and distribution (PMAD); and (5) thrusters. The code optimizes for the following design criteria: minimum mass; minimum radiator area; and low mass/low area. The code also optimizes the following parameters: separation distance; temperature ratio; pressure ratio; and transmission frequency. The discussion is presented in vugraph form.

  1. Modelling robot construction systems

    NASA Technical Reports Server (NTRS)

    Grasso, Chris

    1990-01-01

    TROTER's are small, inexpensive robots that can work together to accomplish sophisticated construction tasks. To understand the issues involved in designing and operating a team of TROTER's, the robots and their components are being modeled. A TROTER system that features standardized component behavior is introduced. An object-oriented model implemented in the Smalltalk programming language is described and the advantages of the object-oriented approach for simulating robot and component interactions are discussed. The presentation includes preliminary results and a discussion of outstanding issues.

  2. System of systems modeling and analysis.

    SciTech Connect

    Campbell, James E.; Anderson, Dennis James; Longsine, Dennis E.; Shirah, Donald N.

    2005-01-01

    This report documents the results of an LDRD program entitled 'System of Systems Modeling and Analysis' that was conducted during FY 2003 and FY 2004. Systems that themselves consist of multiple systems (referred to here as System of Systems or SoS) introduce a level of complexity to systems performance analysis and optimization that is not readily addressable by existing capabilities. The objective of the 'System of Systems Modeling and Analysis' project was to develop an integrated modeling and simulation environment that addresses the complex SoS modeling and analysis needs. The approach to meeting this objective involved two key efforts. First, a static analysis approach, called state modeling, has been developed that is useful for analyzing the average performance of systems over defined use conditions. The state modeling capability supports analysis and optimization of multiple systems and multiple performance measures or measures of effectiveness. The second effort involves time simulation which represents every system in the simulation using an encapsulated state model (State Model Object or SMO). The time simulation can analyze any number of systems including cross-platform dependencies and a detailed treatment of the logistics required to support the systems in a defined mission.

  3. Animal models of systemic sclerosis.

    PubMed

    Morin, Florence; Kavian, Niloufar; Batteux, Frederic

    2015-01-01

    Systemic sclerosis is a systemic connective tissue disorder characterized by the fibrosis of the skin and certain visceral organs, vasculopathy, and immunological abnormalities. Several genetic and inducible animal models of SSc have been developed and are available for research studies. The purpose of this review is to summarize the various animal models of systemic sclerosis and describe the various contributions of these models in terms of understanding the pathophysiology of the condition and searching for new therapeutic strategies for this incurable disease.

  4. Dynamic Modeling of ALS Systems

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2002-01-01

    The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

  5. Structural dynamics system model reduction

    NASA Technical Reports Server (NTRS)

    Chen, J. C.; Rose, T. L.; Wada, B. K.

    1987-01-01

    Loads analysis for structural dynamic systems is usually performed by finite element models. Because of the complexity of the structural system, the model contains large number of degree-of-freedom. The large model is necessary since details of the stress, loads and responses due to mission environments are computed. However, a simplified model is needed for other tasks such as pre-test analysis for modal testing, and control-structural interaction studies. A systematic method of model reduction for modal test analysis is presented. Perhaps it will be of some help in developing a simplified model for the control studies.

  6. Modeling formalisms in Systems Biology

    PubMed Central

    2011-01-01

    Systems Biology has taken advantage of computational tools and high-throughput experimental data to model several biological processes. These include signaling, gene regulatory, and metabolic networks. However, most of these models are specific to each kind of network. Their interconnection demands a whole-cell modeling framework for a complete understanding of cellular systems. We describe the features required by an integrated framework for modeling, analyzing and simulating biological processes, and review several modeling formalisms that have been used in Systems Biology including Boolean networks, Bayesian networks, Petri nets, process algebras, constraint-based models, differential equations, rule-based models, interacting state machines, cellular automata, and agent-based models. We compare the features provided by different formalisms, and discuss recent approaches in the integration of these formalisms, as well as possible directions for the future. PMID:22141422

  7. Modeling formalisms in Systems Biology.

    PubMed

    Machado, Daniel; Costa, Rafael S; Rocha, Miguel; Ferreira, Eugénio C; Tidor, Bruce; Rocha, Isabel

    2011-01-01

    Systems Biology has taken advantage of computational tools and high-throughput experimental data to model several biological processes. These include signaling, gene regulatory, and metabolic networks. However, most of these models are specific to each kind of network. Their interconnection demands a whole-cell modeling framework for a complete understanding of cellular systems. We describe the features required by an integrated framework for modeling, analyzing and simulating biological processes, and review several modeling formalisms that have been used in Systems Biology including Boolean networks, Bayesian networks, Petri nets, process algebras, constraint-based models, differential equations, rule-based models, interacting state machines, cellular automata, and agent-based models. We compare the features provided by different formalisms, and discuss recent approaches in the integration of these formalisms, as well as possible directions for the future. PMID:22141422

  8. Modelling a Simple Mechanical System.

    ERIC Educational Resources Information Center

    Morland, Tim

    1999-01-01

    Provides an example of the modeling power of Mathematics, demonstrated in a piece of A-Level student coursework which was undertaken as part of the MEI Structured Mathematics scheme. A system of two masses and two springs oscillating in one dimension is found to be accurately modeled by a system of linear differential equations. (Author/ASK)

  9. A Model for Systemic Control

    NASA Astrophysics Data System (ADS)

    Schwaninger, Markus; Ambroz, Kristjan; Olaya, Camilo

    2006-06-01

    Where should one begin with a design for the self-control of social systems? That is the question addressed by this paper. The traditional concepts of control rest on the feedback loop; control is essential to the attainment of goals. However, the simple feedback loop is insufficient for the modeling of a control system for an organization or other social system. For those systems, which search for multiple goals, it is necessary to design multilevel control systems incorporating the notion of pre-control. This eminently anticipatory function has hardly been considered by past research. Pre-control as understood here is a higher-order control that takes place between different logical levels of a control system. The Model of Systemic Control (MSC), a framework for multilevel control with pre-control relationships, is expounded and illustrated by means of a System Dynamics model.

  10. Propulsive Reaction Control System Model

    NASA Technical Reports Server (NTRS)

    Brugarolas, Paul; Phan, Linh H.; Serricchio, Frederick; San Martin, Alejandro M.

    2011-01-01

    This software models a propulsive reaction control system (RCS) for guidance, navigation, and control simulation purposes. The model includes the drive electronics, the electromechanical valve dynamics, the combustion dynamics, and thrust. This innovation follows the Mars Science Laboratory entry reaction control system design, and has been created to meet the Mars Science Laboratory (MSL) entry, descent, and landing simulation needs. It has been built to be plug-and-play on multiple MSL testbeds [analysis, Monte Carlo, flight software development, hardware-in-the-loop, and ATLO (assembly, test and launch operations) testbeds]. This RCS model is a C language program. It contains two main functions: the RCS electronics model function that models the RCS FPGA (field-programmable-gate-array) processing and commanding of the RCS valve, and the RCS dynamic model function that models the valve and combustion dynamics. In addition, this software provides support functions to initialize the model states, set parameters, access model telemetry, and access calculated thruster forces.

  11. Model systems in neurotoxicology

    SciTech Connect

    Shahar, A. ); Goldberg, A.M. )

    1987-01-01

    This book contains 33 papers. Some of the titles are: Establishment of cell lines from primary cultures by transfection with SV40 large T antigen gene; Molecular cloning of human cholinesterase genes: Potential applications in neurotoxicology; Neurotoxicity testing of chlorinated hydrocarbons by measuring specific neuronal and glial cell functions; Genetic and pharmacological models of muscle inactivity; and Overexpression of the human CuZnSOD gene in transfected cells: Implication to Down Syndrome.

  12. Launch systems operations cost modeling

    NASA Astrophysics Data System (ADS)

    Jacobs, Mark K.

    1999-01-01

    This paper describes the launch systems operations modeling portion of a larger model development effort, NASA's Space Operations Cost Model (SOCM), led by NASA HQ. The SOCM study team, which includes cost and technical experts from each NASA Field Center and various contractors, has been tasked to model operations costs for all future NASA mission concepts including planetary and Earth orbiting science missions, space facilities, and launch systems. The launch systems operations modeling effort has near term significance for assessing affordability of our next generation launch vehicles and directing technology investments, although it provides only a part of the necessary inputs to assess life cycle costs for all elements that determine affordability for a launch system. Presented here is a methodology to estimate requirements associated with a launch facility infrastructure, or Spaceport, from start-up/initialization into steady-state operation. Included are descriptions of the reference data used, the unique estimating methodology that combines cost lookup tables, parametric relationships, and constructively-developed correlations of cost driver input values to collected reference data, and the output categories that can be used by economic and market models. Also, future plans to improve integration of launch vehicle development cost models, reliability and maintainability models, economic and market models, and this operations model to facilitate overall launch system life cycle performance simulations will be presented.

  13. ASN reputation system model

    NASA Astrophysics Data System (ADS)

    Hutchinson, Steve; Erbacher, Robert F.

    2015-05-01

    Network security monitoring is currently challenged by its reliance on human analysts and the inability for tools to generate indications and warnings for previously unknown attacks. We propose a reputation system based on IP address set membership within the Autonomous System Number (ASN) system. Essentially, a metric generated based on the historic behavior, or misbehavior, of nodes within a given ASN can be used to predict future behavior and provide a mechanism to locate network activity requiring inspection. This will provide reinforcement of notifications and warnings and lead to inspection for ASNs known to be problematic even if initial inspection leads to interpretation of the event as innocuous. We developed proof of concept capabilities to generate the IP address to ASN set membership and analyze the impact of the results. These results clearly show that while some ASNs are one-offs with individual or small numbers of misbehaving IP addresses, there are definitive ASNs with a history of long term and wide spread misbehaving IP addresses. These ASNs with long histories are what we are especially interested in and will provide an additional correlation metric for the human analyst and lead to new tools to aid remediation of these IP address blocks.

  14. System Cost Model

    1996-03-27

    SCM is used for estimation of the life-cycle impacts (costs, health and safety risks) of waste management facilities for mixed low-level, low-level, and transuranic waste. SCM uses parametric cost functions to estimate life-cycle costs for various treatment, storage, and disposal modules which reflect planned and existing waste management facilities at Department of Energy (DOE) installations. SCM also provides transportation costs for intersite transfer of DOE wastes. SCM covers the entire DOE waste management complex tomore » allow system sensitivity analysis including: treatment, storage, and disposal configuration options; treatment technology selection; scheduling options; transportation options; waste stream and volume changes; and site specific conditions.« less

  15. Data management system performance modeling

    NASA Technical Reports Server (NTRS)

    Kiser, Larry M.

    1993-01-01

    This paper discusses analytical techniques that have been used to gain a better understanding of the Space Station Freedom's (SSF's) Data Management System (DMS). The DMS is a complex, distributed, real-time computer system that has been redesigned numerous times. The implications of these redesigns have not been fully analyzed. This paper discusses the advantages and disadvantages for static analytical techniques such as Rate Monotonic Analysis (RMA) and also provides a rationale for dynamic modeling. Factors such as system architecture, processor utilization, bus architecture, queuing, etc. are well suited for analysis with a dynamic model. The significance of performance measures for a real-time system are discussed.

  16. Modeling approaches for active systems

    NASA Astrophysics Data System (ADS)

    Herold, Sven; Atzrodt, Heiko; Mayer, Dirk; Thomaier, Martin

    2006-03-01

    To solve a wide range of vibration problems with the active structures technology, different simulation approaches for several models are needed. The selection of an appropriate modeling strategy is depending, amongst others, on the frequency range, the modal density and the control target. An active system consists of several components: the mechanical structure, at least one sensor and actuator, signal conditioning electronics and the controller. For each individual part of the active system the simulation approaches can be different. To integrate the several modeling approaches into an active system simulation and to ensure a highly efficient and accurate calculation, all sub models must harmonize. For this purpose, structural models considered in this article are modal state-space formulations for the lower frequency range and transfer function based models for the higher frequency range. The modal state-space formulations are derived from finite element models and/or experimental modal analyses. Consequently, the structure models which are based on transfer functions are directly derived from measurements. The transfer functions are identified with the Steiglitz-McBride iteration method. To convert them from the z-domain to the s-domain a least squares solution is implemented. An analytical approach is used to derive models of active interfaces. These models are transferred into impedance formulations. To couple mechanical and electrical sub-systems with the active materials, the concept of impedance modeling was successfully tested. The impedance models are enhanced by adapting them to adequate measurements. The controller design strongly depends on the frequency range and the number of modes to be controlled. To control systems with a small number of modes, techniques such as active damping or independent modal space control may be used, whereas in the case of systems with a large number of modes or with modes that are not well separated, other control

  17. 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.

  18. Kinetic Modeling of Biological Systems

    PubMed Central

    Petzold, Linda; Pettigrew, Michel F.

    2010-01-01

    The dynamics of how the constituent components of a natural system interact defines the spatio-temporal response of the system to stimuli. Modeling the kinetics of the processes that represent a biophysical system has long been pursued with the aim of improving our understanding of the studied system. Due to the unique properties of biological systems, in addition to the usual difficulties faced in modeling the dynamics of physical or chemical systems, biological simulations encounter difficulties that result from intrinsic multiscale and stochastic nature of the biological processes. This chapter discusses the implications for simulation of models involving interacting species with very low copy numbers, which often occur in biological systems and give rise to significant relative fluctuations. The conditions necessitating the use of stochastic kinetic simulation methods and the mathematical foundations of the stochastic simulation algorithms are presented. How the well-organized structural hierarchies often seen in biological systems can lead to multiscale problems, and possible ways to address the encountered computational difficulties are discussed. We present the details of the existing kinetic simulation methods, and discuss their strengths and shortcomings. A list of the publicly available kinetic simulation tools and our reflections for future prospects are also provided. PMID:19381542

  19. Stirling Engine Dynamic System Modeling

    NASA Technical Reports Server (NTRS)

    Nakis, Christopher G.

    2004-01-01

    The Thermo-Mechanical systems branch at the Glenn Research Center focuses a large amount time on Stirling engines. These engines will be used on missions where solar power is inefficient, especially in deep space. I work with Tim Regan and Ed Lewandowski who are currently developing and validating a mathematical model for the Stirling engines. This model incorporates all aspects of the system including, mechanical, electrical and thermodynamic components. Modeling is done through Simplorer, a program capable of running simulations of the model. Once created and then proven to be accurate, a model is used for developing new ideas for engine design. My largest specific project involves varying key parameters in the model and quantifying the results. This can all be done relatively trouble-free with the help of Simplorer. Once the model is complete, Simplorer will do all the necessary calculations. The more complicated part of this project is determining which parameters to vary. Finding key parameters depends on the potential for a value to be independently altered in the design. For example, a change in one dimension may lead to a proportional change to the rest of the model, and no real progress is made. Also, the ability for a changed value to have a substantial impact on the outputs of the system is important. Results will be condensed into graphs and tables with the purpose of better communication and understanding of the data. With the changing of these parameters, a more optimal design can be created without having to purchase or build any models. Also, hours and hours of results can be simulated in minutes. In the long run, using mathematical models can save time and money. Along with this project, I have many other smaller assignments throughout the summer. My main goal is to assist in the processes of model development, validation and testing.

  20. Generalized Environment for Modeling Systems

    SciTech Connect

    2012-02-07

    -04) created at INL to work inside SharePoint. The GUI tool links slider bars and drop downs to specific inputs and output of the ModelCenter model that is executable from SharePoint. The modeler also creates in SAS, dashboards, graphs and tables that are exposed by links and SAS and ModelCenter Web Parts into the SharePoint system. The user can then log into SharePoint, move slider bars and select drop down lists to configure the model parameters, click to run the model, and then view the output results that are based on their particular input choices. The main point is that GEMS eliminates the need for a programmer to connect and create the web artifacts necessary to implement and deliver an executable model or decision aid to customers.

  1. Generalized Environment for Modeling Systems

    2012-02-07

    Part (CW-12-04) created at INL to work inside SharePoint. The GUI tool links slider bars and drop downs to specific inputs and output of the ModelCenter model that is executable from SharePoint. The modeler also creates in SAS, dashboards, graphs and tables that are exposed by links and SAS and ModelCenter Web Parts into the SharePoint system. The user can then log into SharePoint, move slider bars and select drop down lists to configure the model parameters, click to run the model, and then view the output results that are based on their particular input choices. The main point is that GEMS eliminates the need for a programmer to connect and create the web artifacts necessary to implement and deliver an executable model or decision aid to customers.« less

  2. BOOK REVIEW: Modeling Complex Systems

    NASA Astrophysics Data System (ADS)

    Schreckenberg, M.

    2004-10-01

    This book by Nino Boccara presents a compilation of model systems commonly termed as `complex'. It starts with a definition of the systems under consideration and how to build up a model to describe the complex dynamics. The subsequent chapters are devoted to various categories of mean-field type models (differential and recurrence equations, chaos) and of agent-based models (cellular automata, networks and power-law distributions). Each chapter is supplemented by a number of exercises and their solutions. The table of contents looks a little arbitrary but the author took the most prominent model systems investigated over the years (and up until now there has been no unified theory covering the various aspects of complex dynamics). The model systems are explained by looking at a number of applications in various fields. The book is written as a textbook for interested students as well as serving as a compehensive reference for experts. It is an ideal source for topics to be presented in a lecture on dynamics of complex systems. This is the first book on this `wide' topic and I have long awaited such a book (in fact I planned to write it myself but this is much better than I could ever have written it!). Only section 6 on cellular automata is a little too limited to the author's point of view and one would have expected more about the famous Domany--Kinzel model (and more accurate citation!). In my opinion this is one of the best textbooks published during the last decade and even experts can learn a lot from it. Hopefully there will be an actualization after, say, five years since this field is growing so quickly. The price is too high for students but this, unfortunately, is the normal case today. Nevertheless I think it will be a great success!

  3. Modelling robotic systems with DADS

    NASA Technical Reports Server (NTRS)

    Churchill, L. W.; Sharf, I.

    1993-01-01

    With the appearance of general off-the-shelf software packages for the simulation of mechanical systems, modelling and simulation of mechanisms has become an easier task. The authors have recently used one such package, DADS, to model the dynamics of rigid and flexible-link robotic manipulators. In this paper, we present this overview of our learning experiences with DADS, in the hope that it will shorten the learning process for others interested in this software.

  4. Video distribution system cost model

    NASA Technical Reports Server (NTRS)

    Gershkoff, I.; Haspert, J. K.; Morgenstern, B.

    1980-01-01

    A cost model that can be used to systematically identify the costs of procuring and operating satellite linked communications systems is described. The user defines a network configuration by specifying the location of each participating site, the interconnection requirements, and the transmission paths available for the uplink (studio to satellite), downlink (satellite to audience), and voice talkback (between audience and studio) segments of the network. The model uses this information to calculate the least expensive signal distribution path for each participating site. Cost estimates are broken downy by capital, installation, lease, operations and maintenance. The design of the model permits flexibility in specifying network and cost structure.

  5. Parametric Modeling for Fluid Systems

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Martinez, Jonathan

    2013-01-01

    Fluid Systems involves different projects that require parametric modeling, which is a model that maintains consistent relationships between elements as is manipulated. One of these projects is the Neo Liquid Propellant Testbed, which is part of Rocket U. As part of Rocket U (Rocket University), engineers at NASA's Kennedy Space Center in Florida have the opportunity to develop critical flight skills as they design, build and launch high-powered rockets. To build the Neo testbed; hardware from the Space Shuttle Program was repurposed. Modeling for Neo, included: fittings, valves, frames and tubing, between others. These models help in the review process, to make sure regulations are being followed. Another fluid systems project that required modeling is Plant Habitat's TCUI test project. Plant Habitat is a plan to develop a large growth chamber to learn the effects of long-duration microgravity exposure to plants in space. Work for this project included the design and modeling of a duct vent for flow test. Parametric Modeling for these projects was done using Creo Parametric 2.0.

  6. Issues in Modeling System Reliability

    NASA Astrophysics Data System (ADS)

    Cruse, Thomas A.; Annis, Chuck; Booker, Jane; Robinson, David; Sues, Rob

    2002-10-01

    This paper discusses various issues in modeling system reliability. The topics include: 1) Statistical formalisms versus pragmatic numerics; 2) Language; 3) Statistical methods versus reliability-based design methods; 4) Professional bias; and 5) Real issues that need to be identified and resolved prior to certifying designs. This paper is in viewgraph form.

  7. Marine systems analysis and modeling

    NASA Astrophysics Data System (ADS)

    Fedra, K.

    1995-03-01

    Oceanography and marine ecology have a considerable history in the use of computers for modeling both physical and ecological processes. With increasing stress on the marine environment due to human activities such as fisheries and numerous forms of pollution, the analysis of marine problems must increasingly and jointly consider physical, ecological and socio-economic aspects in a broader systems framework that transcends more traditional disciplinary boundaries. This often introduces difficult-to-quantify, “soft” elements, such as values and perceptions, into formal analysis. Thus, the problem domain combines a solid foundation in the physical sciences, with strong elements of ecological, socio-economic and political considerations. At the same time, the domain is also characterized by both a very large volume of some data, and an extremely datapoor situation for other variables, as well as a very high degree of uncertainty, partly due to the temporal and spatial heterogeneity of the marine environment. Consequently, marine systems analysis and management require tools that can integrate these diverse aspects into efficient information systems that can support research as well as planning and also policy- and decisionmaking processes. Supporting scientific research, as well as decision-making processes and the diverse groups and actors involved, requires better access and direct understanding of the information basis as well as easy-to-use, but powerful tools for analysis. Advanced information technology provides the tools to design and implement smart software where, in a broad sense, the emphasis is on the man-machine interface. Symbolic and analogous, graphical interaction, visual representation of problems, integrated data sources, and built-in domain knowledge can effectively support users of complex and complicated software systems. Integration, interaction, visualization and intelligence are key concepts that are discussed in detail, using an

  8. Cotangent Models for Integrable Systems

    NASA Astrophysics Data System (ADS)

    Kiesenhofer, Anna; Miranda, Eva

    2016-07-01

    We associate cotangent models to a neighbourhood of a Liouville torus in symplectic and Poisson manifolds focusing on b-Poisson/b-symplectic manifolds. The semilocal equivalence with such models uses the corresponding action-angle theorems in these settings: the theorem of Liouville-Mineur-Arnold for symplectic manifolds and an action-angle theorem for regular Liouville tori in Poisson manifolds (Laurent- Gengoux et al., IntMath Res Notices IMRN 8: 1839-1869, 2011). Our models comprise regular Liouville tori of Poisson manifolds but also consider the Liouville tori on the singular locus of a b-Poisson manifold. For this latter class of Poisson structures we define a twisted cotangent model. The equivalence with this twisted cotangent model is given by an action-angle theorem recently proved by the authors and Scott (Math. Pures Appl. (9) 105(1):66-85, 2016). This viewpoint of cotangent models provides a new machinery to construct examples of integrable systems, which are especially valuable in the b-symplectic case where not many sources of examples are known. At the end of the paper we introduce non-degenerate singularities as lifted cotangent models on b-symplectic manifolds and discuss some generalizations of these models to general Poisson manifolds.

  9. System modelling for LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Diaz-Aguiló, Marc; Grynagier, Adrien; Rais, Boutheina

    LISA Pathfinder is the technology demonstrator for LISA, a space-borne gravitational waves observatory. The goal of the mission is to characterise the dynamics of the LISA Technology Package (LTP) to prove that on-board experimental conditions are compatible with the de-tection of gravitational waves. The LTP is a drag-free dynamics experiment which includes a control loop with sensors (interferometric and capacitive), actuators (capacitive actuators and thrusters), controlled disturbances (magnetic coils, heaters) and which is subject to various endogenous or exogenous noise sources such as infrared pressure or solar wind. The LTP experiment features new hardware which was never flown in space. The mission has a tight operation timeline as it is constrained to about 100 days. It is therefore vital to have efficient and precise means of investigation and diagnostics to be used during the on-orbit operations. These will be conducted using the LTP Data Analysis toolbox (LTPDA) which allows for simulation, parameter identification and various analyses (covariance analysis, state estimation) given an experimental model. The LTPDA toolbox therefore contains a series of models which are state-space representations of each component in the LTP. The State-Space Models (SSM) are objects of a state-space class within the LTPDA toolbox especially designed to address all the requirements of this tool. The user has access to a set of linear models which represent every satellite subsystem; the models are available in different forms representing 1D, 2D and 3D systems, each with settable symbolic and numeric parameters. To limit the possible errors, the models can be automatically linked to produce composite systems and closed-loops of the LTP. Finally, for the sake of completeness, accuracy and maintainability of the tool, the models contain all the physical information they mimic (i.e. variable units, description of parameters, description of inputs/outputs, etc). Models

  10. Graph modeling systems and methods

    DOEpatents

    Neergaard, Mike

    2015-10-13

    An apparatus and a method for vulnerability and reliability modeling are provided. The method generally includes constructing a graph model of a physical network using a computer, the graph model including a plurality of terminating vertices to represent nodes in the physical network, a plurality of edges to represent transmission paths in the physical network, and a non-terminating vertex to represent a non-nodal vulnerability along a transmission path in the physical network. The method additionally includes evaluating the vulnerability and reliability of the physical network using the constructed graph model, wherein the vulnerability and reliability evaluation includes a determination of whether each terminating and non-terminating vertex represents a critical point of failure. The method can be utilized to evaluate wide variety of networks, including power grid infrastructures, communication network topologies, and fluid distribution systems.

  11. The emergent neural modeling system.

    PubMed

    Aisa, Brad; Mingus, Brian; O'Reilly, Randy

    2008-10-01

    Emergent (http://grey.colorado.edu/emergent) is a powerful tool for the simulation of biologically plausible, complex neural systems that was released in August 2007. Inheriting decades of research and experience in network algorithms and modeling principles from its predecessors, PDP++ and PDP, Emergent has been redesigned as an efficient workspace for academic research and an engaging, easy-to-navigate environment for students. The system provides a modern and intuitive interface for programming and visualization centered around hierarchical, tree-based navigation and drag-and-drop reorganization. Emergent contains familiar, high-level simulation constructs such as Layers and Projections, a wide variety of algorithms, general-purpose data handling and analysis facilities and an integrated virtual environment for developing closed-loop cognitive agents. For students, the traditional role of a textbook has been enhanced by wikis embedded in every project that serve to explain, document, and help newcomers engage the interface and step through models using familiar hyperlinks. For advanced users, the software is easily extensible in all respects via runtime plugins, has a powerful shell with an integrated debugger, and a scripting language that is fully symmetric with the interface. Emergent strikes a balance between detailed, computationally expensive spiking neuron models and abstract, Bayesian or symbolic systems. This middle level of detail allows for the rapid development and successful execution of complex cognitive models while maintaining biological plausibility.

  12. Modeling Advance Life Support Systems

    NASA Technical Reports Server (NTRS)

    Pitts, Marvin; Sager, John; Loader, Coleen; Drysdale, Alan

    1996-01-01

    Activities this summer consisted of two projects that involved computer simulation of bioregenerative life support systems for space habitats. Students in the Space Life Science Training Program (SLSTP) used the simulation, space station, to learn about relationships between humans, fish, plants, and microorganisms in a closed environment. One student complete a six week project to modify the simulation by converting the microbes from anaerobic to aerobic, and then balancing the simulation's life support system. A detailed computer simulation of a closed lunar station using bioregenerative life support was attempted, but there was not enough known about system restraints and constants in plant growth, bioreactor design for space habitats and food preparation to develop an integrated model with any confidence. Instead of a completed detailed model with broad assumptions concerning the unknown system parameters, a framework for an integrated model was outlined and work begun on plant and bioreactor simulations. The NASA sponsors and the summer Fell were satisfied with the progress made during the 10 weeks, and we have planned future cooperative work.

  13. Probabilistic models for feedback systems.

    SciTech Connect

    Grace, Matthew D.; Boggs, Paul T.

    2011-02-01

    In previous work, we developed a Bayesian-based methodology to analyze the reliability of hierarchical systems. The output of the procedure is a statistical distribution of the reliability, thus allowing many questions to be answered. The principal advantage of the approach is that along with an estimate of the reliability, we also can provide statements of confidence in the results. The model is quite general in that it allows general representations of all of the distributions involved, it incorporates prior knowledge into the models, it allows errors in the 'engineered' nodes of a system to be determined by the data, and leads to the ability to determine optimal testing strategies. In this report, we provide the preliminary steps necessary to extend this approach to systems with feedback. Feedback is an essential component of 'complexity' and provides interesting challenges in modeling the time-dependent action of a feedback loop. We provide a mechanism for doing this and analyze a simple case. We then consider some extensions to more interesting examples with local control affecting the entire system. Finally, a discussion of the status of the research is also included.

  14. Discrete modelling of drapery systems

    NASA Astrophysics Data System (ADS)

    Thoeni, Klaus; Giacomini, Anna

    2016-04-01

    Drapery systems are an efficient and cost-effective measure in preventing and controlling rockfall hazards on rock slopes. The simplest form consists of a row of ground anchors along the top of the slope connected to a horizontal support cable from which a wire mesh is suspended down the face of the slope. Such systems are generally referred to as simple or unsecured draperies (Badger and Duffy 2012). Variations such as secured draperies, where a pattern of ground anchors is incorporated within the field of the mesh, and hybrid systems, where the upper part of an unsecured drapery is elevated to intercept rockfalls originating upslope of the installation, are becoming more and more popular. This work presents a discrete element framework for simulation of unsecured drapery systems and its variations. The numerical model is based on the classical discrete element method (DEM) and implemented into the open-source framework YADE (Šmilauer et al., 2010). The model takes all relevant interactions between block, drapery and slope into account (Thoeni et al., 2014) and was calibrated and validated based on full-scale experiments (Giacomini et al., 2012).The block is modelled as a rigid clump made of spherical particles which allows any shape to be approximated. The drapery is represented by a set of spherical particle with remote interactions. The behaviour of the remote interactions is governed by the constitutive behaviour of the wire and generally corresponds to a piecewise linear stress-strain relation (Thoeni et al., 2013). The same concept is used to model wire ropes. The rock slope is represented by rigid triangular elements where material properties (e.g., normal coefficient of restitution, friction angle) are assigned to each triangle. The capabilities of the developed model to simulate drapery systems and estimate the residual hazard involved with such systems is shown. References Badger, T.C., Duffy, J.D. (2012) Drapery systems. In: Turner, A.K., Schuster R

  15. Airfoil flutter model suspension system

    NASA Technical Reports Server (NTRS)

    Reed, Wilmer H. (Inventor)

    1987-01-01

    A wind tunnel suspension system for testing flutter models under various loads and at various angles of attack is described. The invention comprises a mounting bracket assembly affixing the suspension system to the wind tunnel, a drag-link assembly and a compound spring arrangement comprises a plunge spring working in opposition to a compressive spring so as to provide a high stiffness to trim out steady state loads and simultaneously a low stiffness to dynamic loads. By this arrangement an airfoil may be tested for oscillatory response in both plunge and pitch modes while being held under high lifting loads in a wind tunnel.

  16. Models for multimegawatt space power systems

    NASA Astrophysics Data System (ADS)

    Edenburn, M. W.

    1990-06-01

    This report describes models for multimegawatt, space power systems which Sandia's Advanced Power Systems Division has constructed to help evaluate space power systems for SDI's Space Power Office. Five system models and models for associated components are presented for both open (power system waste products are exhausted into space) and closed (no waste products) systems: open, burst mode, hydrogen cooled nuclear reactor - turboalternator system; open, hydrogen-oxygen combustion turboalternator system; closed, nuclear reactor powered Brayton cycle system; closed, liquid metal Rankine cycle system; and closed, in-core, reactor thermionic system. The models estimate performance and mass for the components in each of these systems.

  17. Models for multimegawatt space power systems

    SciTech Connect

    Edenburn, M.W.

    1990-06-01

    This report describes models for multimegawatt, space power systems which Sandia's Advanced Power Systems Division has constructed to help evaluate space power systems for SDI's Space Power Office. Five system models and models for associated components are presented for both open (power system waste products are exhausted into space) and closed (no waste products) systems: open, burst mode, hydrogen cooled nuclear reactor -- turboalternator system; open, hydrogen-oxygen combustion turboalternator system; closed, nuclear reactor powered Brayton cycle system; closed, liquid metal Rankine cycle system; and closed, in-core, reactor therminonic system. The models estimate performance and mass for the components in each of these systems. 17 refs., 8 figs., 15 tabs.

  18. Fire in Earth System Models

    NASA Astrophysics Data System (ADS)

    Kloster, S.; Lasslop, G.

    2015-12-01

    Fire is the most important disturbance process for vegetation impacting the land carbon cycle. Only recently fire models have been developed that are able to represent the important role of fire for vegetation dynamics and land carbon cycling at global scale. Here, we investigate how fire is represented in Earth System Models (ESMs) that participated in the 5th Climate Model Intercomparison Project (CMIP5) and present more recent advances in global fire modeling for upcoming CMIPs. Burned area and carbon emissions from fire are among the variables reported in CMIP5. ESMs from CMIP5 use common simulation and output protocols, enabling direct comparisons between models. For this study ESMs were selected from the CMIP5 repository based on the availability of burned area and/or carbon emissions from fires for the historical and the rcp2.6/4.5/8.5 simulations. All ESMs analyzed show a comparable global total burned area of about 150 to 200 Mha burned per year for the present day period, which is lower than satellite based observations (e.g. GFEDv3 ~370 Mha/year). Most models show over the historical period (1850 - 2005) only a weak change in global fire activity and for the future (2006 - 2100) strong increases in fire activity for rcp4.5 and rcp8.5, but only moderate changes for the rcp2.6 projection. Regionally the response differs strongly between the models, which is partly related to different climate projections. We further analysed the simulated changes in fire activity with respect to simulated changes in temperature and precipitation from which no general pattern of the sensitivity of fire carbon emissions towards changes in climate emerged. We will end the presentation with more recent results from the JSBACH-SPITFIRE model to give some insights into the capability of global fire models that will take part in upcoming CMIPs.

  19. Aerial Measuring System Sensor Modeling

    SciTech Connect

    R. S. Detwiler

    2002-04-01

    This project deals with the modeling the Aerial Measuring System (AMS) fixed-wing and rotary-wing sensor systems, which are critical U.S. Department of Energy's National Nuclear Security Administration (NNSA) Consequence Management assets. The fixed-wing system is critical in detecting lost or stolen radiography or medical sources, or mixed fission products as from a commercial power plant release at high flying altitudes. The helicopter is typically used at lower altitudes to determine ground contamination, such as in measuring americium from a plutonium ground dispersal during a cleanup. Since the sensitivity of these instruments as a function of altitude is crucial in estimating detection limits of various ground contaminations and necessary count times, a characterization of their sensitivity as a function of altitude and energy is needed. Experimental data at altitude as well as laboratory benchmarks is important to insure that the strong effects of air attenuation are modeled correctly. The modeling presented here is the first attempt at such a characterization of the equipment for flying altitudes. The sodium iodide (NaI) sensors utilized with these systems were characterized using the Monte Carlo N-Particle code (MCNP) developed at Los Alamos National Laboratory. For the fixed wing system, calculations modeled the spectral response for the 3-element NaI detector pod and High-Purity Germanium (HPGe) detector, in the relevant energy range of 50 keV to 3 MeV. NaI detector responses were simulated for both point and distributed surface sources as a function of gamma energy and flying altitude. For point sources, photopeak efficiencies were calculated for a zero radial distance and an offset equal to the altitude. For distributed sources approximating an infinite plane, gross count efficiencies were calculated and normalized to a uniform surface deposition of 1 {micro}Ci/m{sup 2}. The helicopter calculations modeled the transport of americium-241 ({sup 241}Am

  20. 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.

  1. Modeling software systems by domains

    NASA Technical Reports Server (NTRS)

    Dippolito, Richard; Lee, Kenneth

    1992-01-01

    The Software Architectures Engineering (SAE) Project at the Software Engineering Institute (SEI) has developed engineering modeling techniques that both reduce the complexity of software for domain-specific computer systems and result in systems that are easier to build and maintain. These techniques allow maximum freedom for system developers to apply their domain expertise to software. We have applied these techniques to several types of applications, including training simulators operating in real time, engineering simulators operating in non-real time, and real-time embedded computer systems. Our modeling techniques result in software that mirrors both the complexity of the application and the domain knowledge requirements. We submit that the proper measure of software complexity reflects neither the number of software component units nor the code count, but the locus of and amount of domain knowledge. As a result of using these techniques, domain knowledge is isolated by fields of engineering expertise and removed from the concern of the software engineer. In this paper, we will describe kinds of domain expertise, describe engineering by domains, and provide relevant examples of software developed for simulator applications using the techniques.

  2. Quantitative Predictive Models for Systemic Toxicity (SOT)

    EPA Science Inventory

    Models to identify systemic and specific target organ toxicity were developed to help transition the field of toxicology towards computational models. By leveraging multiple data sources to incorporate read-across and machine learning approaches, a quantitative model of systemic ...

  3. Models of Multiple System Atrophy

    PubMed Central

    Fellner, Lisa; Wenning, Gregor K.; Stefanova, Nadia

    2016-01-01

    Multiple system atrophy (MSA) is a predominantly sporadic, adult-onset, fatal neurodegenerative disease of unknown etiology. MSA is characterized by autonomic failure, levodopa-unresponsive parkinsonism, cerebellar ataxia and pyramidal signs in any combination. MSA belongs to a group of neurodegenerative disorders termed α-synucleinopathies, which also include Parkinson’s disease and dementia with Lewy bodies. Their common pathological feature is the occurrence of abnormal α-synuclein positive inclusions in neurons or glial cells. In MSA, the main cell type presenting aggregates composed of α-synuclein are oligodendroglial cells. This pathological hallmark, also called glial cytoplasmic inclusions (GCIs), is associated with progressive and profound neuronal loss in various regions of the brain. The development of animal models of MSA is justified by the limited understanding of the mechanisms of neurodegeneration and GCIs formation, which is paralleled by a lack of therapeutic strategies. Two main types of rodent models have been generated to replicate different features of MSA neuropathology. On one hand, neurotoxin-based models have been produced to reproduce neuronal loss in substantia nigra pars compacta and striatum. On the other hand, transgenic mouse models with overexpression of α-synuclein in oligodendroglia have been used to reproduce GCIs-related pathology. This chapter gives an overview of the atypical Parkinson’s syndrome MSA and summarizes the currently available MSA animal models and their relevance for pre-clinical testing of disease-modifying therapies. PMID:24338664

  4. ISSM: Ice Sheet System Model

    NASA Technical Reports Server (NTRS)

    Larour, Eric; Schiermeier, John E.; Seroussi, Helene; Morlinghem, Mathieu

    2013-01-01

    In order to have the capability to use satellite data from its own missions to inform future sea-level rise projections, JPL needed a full-fledged ice-sheet/iceshelf flow model, capable of modeling the mass balance of Antarctica and Greenland into the near future. ISSM was developed with such a goal in mind, as a massively parallelized, multi-purpose finite-element framework dedicated to ice-sheet modeling. ISSM features unstructured meshes (Tria in 2D, and Penta in 3D) along with corresponding finite elements for both types of meshes. Each finite element can carry out diagnostic, prognostic, transient, thermal 3D, surface, and bed slope simulations. Anisotropic meshing enables adaptation of meshes to a certain metric, and the 2D Shelfy-Stream, 3D Blatter/Pattyn, and 3D Full-Stokes formulations capture the bulk of the ice-flow physics. These elements can be coupled together, based on the Arlequin method, so that on a large scale model such as Antarctica, each type of finite element is used in the most efficient manner. For each finite element referenced above, ISSM implements an adjoint. This adjoint can be used to carry out model inversions of unknown model parameters, typically ice rheology and basal drag at the ice/bedrock interface, using a metric such as the observed InSAR surface velocity. This data assimilation capability is crucial to allow spinning up of ice flow models using available satellite data. ISSM relies on the PETSc library for its vectors, matrices, and solvers. This allows ISSM to run efficiently on any parallel platform, whether shared or distrib- ISSM: Ice Sheet System Model NASA's Jet Propulsion Laboratory, Pasadena, California uted. It can run on the largest clusters, and is fully scalable. This allows ISSM to tackle models the size of continents. ISSM is embedded into MATLAB and Python, both open scientific platforms. This improves its outreach within the science community. It is entirely written in C/C++, which gives it flexibility in its

  5. NUCLEAR ENERGY SYSTEM COST MODELING

    SciTech Connect

    Francesco Ganda; Brent Dixon

    2012-09-01

    The U.S. Department of Energy’s Fuel Cycle Technologies (FCT) Program is preparing to perform an evaluation of the full range of possible Nuclear Energy Systems (NES) in 2013. These include all practical combinations of fuels and transmuters (reactors and sub-critical systems) in single and multi-tier combinations of burners and breeders with no, partial, and full recycle. As part of this evaluation, Levelized Cost of Electricity at Equilibrium (LCAE) ranges for each representative system will be calculated. To facilitate the cost analyses, the 2009 Advanced Fuel Cycle Cost Basis Report is being amended to provide up-to-date cost data for each step in the fuel cycle, and a new analysis tool, NE-COST, has been developed. This paper explains the innovative “Island” approach used by NE-COST to streamline and simplify the economic analysis effort and provides examples of LCAE costs generated. The Island approach treats each transmuter (or target burner) and the associated fuel cycle facilities as a separate analysis module, allowing reuse of modules that appear frequently in the NES options list. For example, a number of options to be screened will include a once-through uranium oxide (UOX) fueled light water reactor (LWR). The UOX LWR may be standalone, or may be the first stage in a multi-stage system. Using the Island approach, the UOX LWR only needs to be modeled once and the module can then be reused on subsequent fuel cycles. NE-COST models the unit operations and life cycle costs associated with each step of the fuel cycle on each island. This includes three front-end options for supplying feedstock to fuel fabrication (mining/enrichment, reprocessing of used fuel from another island, and/or reprocessing of this island’s used fuel), along with the transmuter and back-end storage/disposal. Results of each island are combined based on the fractional energy generated by each islands in an equilibrium system. The cost analyses use the probability

  6. Mathematical modeling of radio systems and devices

    NASA Astrophysics Data System (ADS)

    Borisov, Iu. P.; Tsvetnov, V. V.

    Methods for developing mathematical models of radio systems and devices are presented with emphasis on the functional approach to the modeling of radio systems. In particular, attention is given to the formal description of radio systems, computer-aided modeling of radio systems, a classification of methods of radio system modeling, and methods of mathematical description of signals and noise. Specific methods discussed include the carrier method, the complex envelope method, the method of statistical equivalents, and the information parameter method.

  7. National Energy Modeling System (NEMS)

    DOE Data Explorer

    The National Energy Modeling System (NEMS) is a computer-based, energy-economy modeling system of U.S. through 2030. NEMS projects the production, imports, conversion, consumption, and prices of energy, subject to assumptions on macroeconomic and financial factors, world energy markets, resource availability and costs, behavioral and technological choice criteria, cost and performance characteristics of energy technologies, and demographics. NEMS was designed and implemented by the Energy Information Administration (EIA) of the U.S. Department of Energy (DOE). NEMS can be used to analyze the effects of existing and proposed government laws and regulations related to energy production and use; the potential impact of new and advanced energy production, conversion, and consumption technologies; the impact and cost of greenhouse gas control; the impact of increased use of renewable energy sources; and the potential savings from increased efficiency of energy use; and the impact of regulations on the use of alternative or reformulated fuels. NEMS has also been used for a number of special analyses at the request of the Administration, U.S. Congress, other offices of DOE and other government agencies, who specify the scenarios and assumptions for the analysis. Modules allow analyses to be conducted in energy topic areas such as residential demand, industrial demand, electricity market, oil and gas supply, renewable fuels, etc.

  8. Geochemical Modeling Of Aqueous Systems

    1995-09-07

    EQ3/6 is a software package for geochemical modeling of aqueous systems. This description pertains to version 7.2b. It addresses aqueous speciation, thermodynamic equilibrium, disequilibrium, and chemical kinetics. The major components of the package are EQ3NR, a speciation-solubility code, and EQ6 a reaction path code. EQ3NR is useful for analyzing groundwater chemistry data, calculating solubility limits, and determining whether certain reactions are in states of equilibrium or disequilibrium. It also initializes EQ6 calculations. EQ6 models themore » consequences of reacting an aqueous solution with a specified set of reactants (e.g., minerals or waste forms). It can also model fluid mixing and the effects of changes in temperature. Each of five supporting data files contain both standard state and activity coefficient-related data. Three support the use of the Davies or B-dot equations for the activity coefficients; the other two support the use of Pitzer''s equations. The temperature range of the thermodynamic data on the data files varies from 25 degrees C only to 0-300 degrees C.« less

  9. Relaxation Models for Glassy Systems

    NASA Astrophysics Data System (ADS)

    Ajay

    In this thesis we explore some models based on constrained dynamics to understand the origin and ubiquity of the stretched exponential relaxation q(t) = exp(-(t/tau)^{ beta}). The first chapter has a pedagogical introduction to this field. Then we explore two models based primarily on constraints to see whether they would exhibit a stretched exponential relaxation. The first is a sliding block type of model based on a child's puzzle which has blocks and vacancies. The blocks can move only when they are nearest neighbor to a vacancy. We simulate random walk of the blocks and explore the relaxation behavior to equilibrium. We obtain three regimes of relaxation. In the short time regime (where the constraints are strong) we see a stretched exponential behavior. The intermediate time regime is best described as a simple random walk and we obtain a power law (with exponent 1/2). The long time behavior is a simple exponential, as expected. We do a Monte Carlo simulation of random walk on a bond-diluted hypercube. The site-diluted version of this model was suggested by Campbell as an explanation of the relaxation behavior seen in spin glasses. We come to it from the perspective of a system which exemplifies only constraints and nothing else (we have hard constraints with {cal H} = 0). We see that the relaxation to equilibrium is exponential for all p >=q 1/2 and below that it is a stretched exponential. In fact, the beta decreases as p decreases and attains a value of 1/4 at the percolation threshold of p = 1/n, where n is the dimensionality of the hypercube. We also do a calculation for determining the probability of connectivity for finite graphs. This demonstrates that the usual numerical results provided in graph theory, which are in the limit of infinite graphs, are not accurate for finite graphs. The final chapter has a conclusion. We also propose a model based on random graphs and percolation for studying sliding block kind of models.

  10. Modeling the Earth System, volume 3

    NASA Technical Reports Server (NTRS)

    Ojima, Dennis (Editor)

    1992-01-01

    The topics covered fall under the following headings: critical gaps in the Earth system conceptual framework; development needs for simplified models; and validating Earth system models and their subcomponents.

  11. Using the Model Coupling Toolkit to couple earth system models

    USGS Publications Warehouse

    Warner, J.C.; Perlin, N.; Skyllingstad, E.D.

    2008-01-01

    Continued advances in computational resources are providing the opportunity to operate more sophisticated numerical models. Additionally, there is an increasing demand for multidisciplinary studies that include interactions between different physical processes. Therefore there is a strong desire to develop coupled modeling systems that utilize existing models and allow efficient data exchange and model control. The basic system would entail model "1" running on "M" processors and model "2" running on "N" processors, with efficient exchange of model fields at predetermined synchronization intervals. Here we demonstrate two coupled systems: the coupling of the ocean circulation model Regional Ocean Modeling System (ROMS) to the surface wave model Simulating WAves Nearshore (SWAN), and the coupling of ROMS to the atmospheric model Coupled Ocean Atmosphere Prediction System (COAMPS). Both coupled systems use the Model Coupling Toolkit (MCT) as a mechanism for operation control and inter-model distributed memory transfer of model variables. In this paper we describe requirements and other options for model coupling, explain the MCT library, ROMS, SWAN and COAMPS models, methods for grid decomposition and sparse matrix interpolation, and provide an example from each coupled system. Methods presented in this paper are clearly applicable for coupling of other types of models. ?? 2008 Elsevier Ltd. All rights reserved.

  12. Modeling of Spacecraft Advanced Chemical Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Benfield, Michael P. J.; Belcher, Jeremy A.

    2004-01-01

    This paper outlines the development of the Advanced Chemical Propulsion System (ACPS) model for Earth and Space Storable propellants. This model was developed by the System Technology Operation of SAIC-Huntsville for the NASA MSFC In-Space Propulsion Project Office. Each subsystem of the model is described. Selected model results will also be shown to demonstrate the model's ability to evaluate technology changes in chemical propulsion systems.

  13. New model systems for experimental evolution.

    PubMed

    Collins, Sinéad

    2013-07-01

    Microbial experimental evolution uses a few well-characterized model systems to answer fundamental questions about how evolution works. This special section highlights novel model systems for experimental evolution, with a focus on marine model systems that can be used to understand evolutionary responses to global change in the oceans.

  14. Modeling Power Systems as Complex Adaptive Systems

    SciTech Connect

    Chassin, David P.; Malard, Joel M.; Posse, Christian; Gangopadhyaya, Asim; Lu, Ning; Katipamula, Srinivas; Mallow, J V.

    2004-12-30

    Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today's most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This report explores the state-of-the-art physical analogs for understanding the behavior of some econophysical systems and deriving stable and robust control strategies for using them. We review and discuss applications of some analytic methods based on a thermodynamic metaphor, according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood. We apply these methods to the question of how power markets can be expected to behave under a variety of conditions.

  15. Modelling Information System Dynamics: A Perspective.

    ERIC Educational Resources Information Center

    Oswitch, Pauline

    1983-01-01

    Describes British Library's work on Systems Dynamics, a set of techniques for building simulation models based on analysis of information feedback loops. Highlights include macro-simulation modelling activities of social science disciplines, systems analyses and models of information retrieval processes and library services, policy models, and…

  16. Visual computing model for immune system and medical system.

    PubMed

    Gong, Tao; Cao, Xinxue; Xiong, Qin

    2015-01-01

    Natural immune system is an intelligent self-organizing and adaptive system, which has a variety of immune cells with different types of immune mechanisms. The mutual cooperation between the immune cells shows the intelligence of this immune system, and modeling this immune system has an important significance in medical science and engineering. In order to build a comprehensible model of this immune system for better understanding with the visualization method than the traditional mathematic model, a visual computing model of this immune system was proposed and also used to design a medical system with the immune system, in this paper. Some visual simulations of the immune system were made to test the visual effect. The experimental results of the simulations show that the visual modeling approach can provide a more effective way for analyzing this immune system than only the traditional mathematic equations.

  17. NASA's SPICE System Models the Solar System

    NASA Technical Reports Server (NTRS)

    Acton, Charles

    1996-01-01

    SPICE is NASA's multimission, multidiscipline information system for assembling, distributing, archiving, and accessing space science geometry and related data used by scientists and engineers for mission design and mission evaluation, detailed observation planning, mission operations, and science data analysis.

  18. Generic CSP Performance Model for NREL's System Advisor Model: Preprint

    SciTech Connect

    Wagner, M. J.; Zhu, G.

    2011-08-01

    The suite of concentrating solar power (CSP) modeling tools in NREL's System Advisor Model (SAM) includes technology performance models for parabolic troughs, power towers, and dish-Stirling systems. Each model provides the user with unique capabilities that are catered to typical design considerations seen in each technology. Since the scope of the various models is generally limited to common plant configurations, new CSP technologies, component geometries, and subsystem combinations can be difficult to model directly in the existing SAM technology models. To overcome the limitations imposed by representative CSP technology models, NREL has developed a 'Generic Solar System' (GSS) performance model for use in SAM. This paper discusses the formulation and performance considerations included in this model and verifies the model by comparing its results with more detailed models.

  19. Analysis hierarchical model for discrete event systems

    NASA Astrophysics Data System (ADS)

    Ciortea, E. M.

    2015-11-01

    The This paper presents the hierarchical model based on discrete event network for robotic systems. Based on the hierarchical approach, Petri network is analysed as a network of the highest conceptual level and the lowest level of local control. For modelling and control of complex robotic systems using extended Petri nets. Such a system is structured, controlled and analysed in this paper by using Visual Object Net ++ package that is relatively simple and easy to use, and the results are shown as representations easy to interpret. The hierarchical structure of the robotic system is implemented on computers analysed using specialized programs. Implementation of hierarchical model discrete event systems, as a real-time operating system on a computer network connected via a serial bus is possible, where each computer is dedicated to local and Petri model of a subsystem global robotic system. Since Petri models are simplified to apply general computers, analysis, modelling, complex manufacturing systems control can be achieved using Petri nets. Discrete event systems is a pragmatic tool for modelling industrial systems. For system modelling using Petri nets because we have our system where discrete event. To highlight the auxiliary time Petri model using transport stream divided into hierarchical levels and sections are analysed successively. Proposed robotic system simulation using timed Petri, offers the opportunity to view the robotic time. Application of goods or robotic and transmission times obtained by measuring spot is obtained graphics showing the average time for transport activity, using the parameters sets of finished products. individually.

  20. Model-Based Prognostics of Hybrid Systems

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew; Roychoudhury, Indranil; Bregon, Anibal

    2015-01-01

    Model-based prognostics has become a popular approach to solving the prognostics problem. However, almost all work has focused on prognostics of systems with continuous dynamics. In this paper, we extend the model-based prognostics framework to hybrid systems models that combine both continuous and discrete dynamics. In general, most systems are hybrid in nature, including those that combine physical processes with software. We generalize the model-based prognostics formulation to hybrid systems, and describe the challenges involved. We present a general approach for modeling hybrid systems, and overview methods for solving estimation and prediction in hybrid systems. As a case study, we consider the problem of conflict (i.e., loss of separation) prediction in the National Airspace System, in which the aircraft models are hybrid dynamical systems.

  1. Human systems dynamics: Toward a computational model

    NASA Astrophysics Data System (ADS)

    Eoyang, Glenda H.

    2012-09-01

    A robust and reliable computational model of complex human systems dynamics could support advancements in theory and practice for social systems at all levels, from intrapersonal experience to global politics and economics. Models of human interactions have evolved from traditional, Newtonian systems assumptions, which served a variety of practical and theoretical needs of the past. Another class of models has been inspired and informed by models and methods from nonlinear dynamics, chaos, and complexity science. None of the existing models, however, is able to represent the open, high dimension, and nonlinear self-organizing dynamics of social systems. An effective model will represent interactions at multiple levels to generate emergent patterns of social and political life of individuals and groups. Existing models and modeling methods are considered and assessed against characteristic pattern-forming processes in observed and experienced phenomena of human systems. A conceptual model, CDE Model, based on the conditions for self-organizing in human systems, is explored as an alternative to existing models and methods. While the new model overcomes the limitations of previous models, it also provides an explanatory base and foundation for prospective analysis to inform real-time meaning making and action taking in response to complex conditions in the real world. An invitation is extended to readers to engage in developing a computational model that incorporates the assumptions, meta-variables, and relationships of this open, high dimension, and nonlinear conceptual model of the complex dynamics of human systems.

  2. Comparison of Photovoltaic Models in the System Advisor Model: Preprint

    SciTech Connect

    Blair, N. J.; Dobos, A. P.; Gilman, P.

    2013-08-01

    The System Advisor Model (SAM) is free software developed by the National Renewable Energy Laboratory (NREL) for predicting the performance of renewable energy systems and analyzing the financial feasibility of residential, commercial, and utility-scale grid-connected projects. SAM offers several options for predicting the performance of photovoltaic (PV) systems. The model requires that the analyst choose from three PV system models, and depending on that choice, possibly choose from three module and two inverter component models. To obtain meaningful results from SAM, the analyst must be aware of the differences between the model options and their applicability to different modeling scenarios. This paper presents an overview the different PV model options and presents a comparison of results for a 200-kW system using different model options.

  3. An online model composition tool for system biology models

    PubMed Central

    2013-01-01

    Background There are multiple representation formats for Systems Biology computational models, and the Systems Biology Markup Language (SBML) is one of the most widely used. SBML is used to capture, store, and distribute computational models by Systems Biology data sources (e.g., the BioModels Database) and researchers. Therefore, there is a need for all-in-one web-based solutions that support advance SBML functionalities such as uploading, editing, composing, visualizing, simulating, querying, and browsing computational models. Results We present the design and implementation of the Model Composition Tool (Interface) within the PathCase-SB (PathCase Systems Biology) web portal. The tool helps users compose systems biology models to facilitate the complex process of merging systems biology models. We also present three tools that support the model composition tool, namely, (1) Model Simulation Interface that generates a visual plot of the simulation according to user’s input, (2) iModel Tool as a platform for users to upload their own models to compose, and (3) SimCom Tool that provides a side by side comparison of models being composed in the same pathway. Finally, we provide a web site that hosts BioModels Database models and a separate web site that hosts SBML Test Suite models. Conclusions Model composition tool (and the other three tools) can be used with little or no knowledge of the SBML document structure. For this reason, students or anyone who wants to learn about systems biology will benefit from the described functionalities. SBML Test Suite models will be a nice starting point for beginners. And, for more advanced purposes, users will able to access and employ models of the BioModels Database as well. PMID:24006914

  4. A model for plant lighting system selection

    NASA Technical Reports Server (NTRS)

    Ciolkosz, D. E.; Albright, L. D.; Sager, J. C.; Langhans, R. W.

    2002-01-01

    A decision model is presented that compares lighting systems for a plant growth scenario and chooses the most appropriate system from a given set of possible choices. The model utilizes a Multiple Attribute Utility Theory approach, and incorporates expert input and performance simulations to calculate a utility value for each lighting system being considered. The system with the highest utility is deemed the most appropriate system. The model was applied to a greenhouse scenario, and analyses were conducted to test the model's output for validity. Parameter variation indicates that the model performed as expected. Analysis of model output indicates that differences in utility among the candidate lighting systems were sufficiently large to give confidence that the model's order of selection was valid.

  5. Designing control system information models

    NASA Technical Reports Server (NTRS)

    Panin, K. I.; Zinchenko, V. P.

    1973-01-01

    Problems encountered in modeling information models are discussed, Data cover condition, functioning of the object of control, and the environment involved in the control. Other parameters needed for the model include: (1) information for forming an image of the real situation, (2) data for analyzing and evaluating an evolving situation, (3) planning actions, and (4) data for observing and evaluating the results of model realization.

  6. Electronic Education System Model-2

    ERIC Educational Resources Information Center

    Güllü, Fatih; Kuusik, Rein; Laanpere, Mart

    2015-01-01

    In this study we presented new EES Model-2 extended from EES model for more productive implementation in e-learning process design and modelling in higher education. The most updates were related to uppermost instructional layer. We updated learning processes object of the layer for adaptation of educational process for young and old people,…

  7. Multiple system modelling of waste management.

    PubMed

    Eriksson, Ola; Bisaillon, Mattias

    2011-12-01

    Due to increased environmental awareness, planning and performance of waste management has become more and more complex. Therefore waste management has early been subject to different types of modelling. Another field with long experience of modelling and systems perspective is energy systems. The two modelling traditions have developed side by side, but so far there are very few attempts to combine them. Waste management systems can be linked together with energy systems through incineration plants. The models for waste management can be modelled on a quite detailed level whereas surrounding systems are modelled in a more simplistic way. This is a problem, as previous studies have shown that assumptions on the surrounding system often tend to be important for the conclusions. In this paper it is shown how two models, one for the district heating system (MARTES) and another one for the waste management system (ORWARE), can be linked together. The strengths and weaknesses with model linking are discussed when compared to simplistic assumptions on effects in the energy and waste management systems. It is concluded that the linking of models will provide a more complete, correct and credible picture of the consequences of different simultaneous changes in the systems. The linking procedure is easy to perform and also leads to activation of project partners. However, the simulation procedure is a bit more complicated and calls for the ability to run both models.

  8. Dispersion Modeling in Complex Urban Systems

    EPA Science Inventory

    Models are used to represent real systems in an understandable way. They take many forms. A conceptual model explains the way a system works. In environmental studies, for example, a conceptual model may delineate all the factors and parameters for determining how a particle move...

  9. Building a generalized distributed system model

    NASA Technical Reports Server (NTRS)

    Mukkamala, Ravi

    1991-01-01

    A number of topics related to building a generalized distributed system model are discussed. The effects of distributed database modeling on evaluation of transaction rollbacks, the measurement of effects of distributed database models on transaction availability measures, and a performance analysis of static locking in replicated distributed database systems are covered.

  10. NASA Lewis Wind Tunnel Model Systems Criteria

    NASA Technical Reports Server (NTRS)

    Soeder, Ronald H.; Haller, Henry C.

    1994-01-01

    This report describes criteria for the design, analysis, quality assurance, and documentation of models or test articles that are to be tested in the aeropropulsion facilities at the NASA Lewis Research Center. The report presents three methods for computing model allowable stresses on the basis of the yield stress or ultimate stress, and it gives quality assurance criteria for models tested in Lewis' aeropropulsion facilities. Both customer-furnished model systems and in-house model systems are discussed. The functions of the facility manager, project engineer, operations engineer, research engineer, and facility electrical engineer are defined. The format for pretest meetings, prerun safety meetings, and the model criteria review are outlined Then, the format for the model systems report (a requirement for each model that is to be tested at NASA Lewis) is described, the engineers that are responsible for developing the model systems report are listed, and the time table for its delivery to the facility manager is given.

  11. World Energy Projection System Plus Model Documentation: Refinery Model

    EIA Publications

    2016-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Refinery Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  12. World Energy Projection System Plus Model Documentation: Industrial Model

    EIA Publications

    2016-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) World Industrial Model (WIM). It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  13. World Energy Projection System Plus Model Documentation: Residential Model

    EIA Publications

    2016-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Residential Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  14. World Energy Projection System Plus Model Documentation: Main Model

    EIA Publications

    2016-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Main Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  15. World Energy Projection System Plus Model Documentation: Transportation Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) International Transportation model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  16. World Energy Projection System Plus Model Documentation: Industrial Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) World Industrial Model (WIM). It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  17. World Energy Projection System Plus Model Documentation: Residential Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Residential Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  18. World Energy Projection System Plus Model Documentation: Main Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Main Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  19. World Energy Projection System Plus Model Documentation: World Electricity Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) World Electricity Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  20. World Energy Projection System Plus Model Documentation: District Heat Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) District Heat Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  1. World Energy Projection System Plus Model Documentation: Greenhouse Gases Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Greenhouse Gases Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  2. World Energy Projection System Plus Model Documentation: Natural Gas Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Natural Gas Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  3. World Energy Projection System Plus Model Documentation: Coal Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Coal Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  4. Laser beam modeling in optical storage systems

    NASA Technical Reports Server (NTRS)

    Treptau, J. P.; Milster, T. D.; Flagello, D. G.

    1991-01-01

    A computer model has been developed that simulates light propagating through an optical data storage system. A model of a laser beam that originates at a laser diode, propagates through an optical system, interacts with a optical disk, reflects back from the optical disk into the system, and propagates to data and servo detectors is discussed.

  5. Network and adaptive system of systems modeling and analysis.

    SciTech Connect

    Lawton, Craig R.; Campbell, James E. Dr.; Anderson, Dennis James; Eddy, John P.

    2007-05-01

    This report documents the results of an LDRD program entitled ''Network and Adaptive System of Systems Modeling and Analysis'' that was conducted during FY 2005 and FY 2006. The purpose of this study was to determine and implement ways to incorporate network communications modeling into existing System of Systems (SoS) modeling capabilities. Current SoS modeling, particularly for the Future Combat Systems (FCS) program, is conducted under the assumption that communication between the various systems is always possible and occurs instantaneously. A more realistic representation of these communications allows for better, more accurate simulation results. The current approach to meeting this objective has been to use existing capabilities to model network hardware reliability and adding capabilities to use that information to model the impact on the sustainment supply chain and operational availability.

  6. EXPOSURE ANALYSIS MODELING SYSTEM (EXAMS): USER MANUAL AND SYSTEM DOCUMENTATION

    EPA Science Inventory

    The Exposure Analysis Modeling System, first published in 1982 (EPA-600/3-82-023), provides interactive computer software for formulating aquatic ecosystem models and rapidly evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals - pesticides, ...

  7. Generic Model Host System Design

    SciTech Connect

    Chu, Chungming; Wu, Juhao; Qiang, Ji; Shen, Guobao; /Brookhaven

    2012-06-22

    There are many simulation codes for accelerator modelling; each one has some strength but not all. A platform which can host multiple modelling tools would be ideal for various purposes. The model platform along with infrastructure support can be used not only for online applications but also for offline purposes. Collaboration is formed for the effort of providing such a platform. In order to achieve such a platform, a set of common physics data structure has to be set. Application Programming Interface (API) for physics applications should also be defined within a model data provider. A preliminary platform design and prototype is discussed.

  8. System Dynamics Models and Institutional Pricing Decisions.

    ERIC Educational Resources Information Center

    Chen, Fiona

    1986-01-01

    A system dynamics model for the pricing of tuition is presented, illustrating how such models enable decision-makers to anticipate cause-and-effect relationships and test alternative courses of action. (Author)

  9. World Energy Projection System Plus Model Documentation: Commercial Model

    EIA Publications

    2016-01-01

    The Commercial Model of the World Energy Projection System Plus (WEPS ) is an energy demand modeling system of the world commercial end?use sector at a regional level. This report describes the version of the Commercial Model that was used to produce the commercial sector projections published in the International Energy Outlook 2016 (IEO2016). The Commercial Model is one of 13 components of the WEPS system. The WEPS is a modular system, consisting of a number of separate energy models that are communicate and work with each other through an integrated system model. The model components are each developed independently, but are designed with well?defined protocols for system communication and interactivity. The WEPS modeling system uses a shared database (the “restart” file) that allows all the models to communicate with each other when they are run in sequence over a number of iterations. The overall WEPS system uses an iterative solution technique that forces convergence of consumption and supply pressures to solve for an equilibrium price.

  10. Error Propagation in a System Model

    NASA Technical Reports Server (NTRS)

    Schloegel, Kirk (Inventor); Bhatt, Devesh (Inventor); Oglesby, David V. (Inventor); Madl, Gabor (Inventor)

    2015-01-01

    Embodiments of the present subject matter can enable the analysis of signal value errors for system models. In an example, signal value errors can be propagated through the functional blocks of a system model to analyze possible effects as the signal value errors impact incident functional blocks. This propagation of the errors can be applicable to many models of computation including avionics models, synchronous data flow, and Kahn process networks.

  11. Hubble Space Telescope electrical power system model

    NASA Technical Reports Server (NTRS)

    Baggett, Randy; Miller, Jim; Leisgang, Tom

    1988-01-01

    This paper describes one of the most comprehensive models ever developed for a spacecraft electrical power system (EPS). The model was developed for the Hubble Space Telescope (HST) to evaluate vehicle power system performance and to assist in scheduling maintenance and refurbishment missions by providing data needed to forecast EPS power and energy margins for the mission phases being planned. The EPS model requires a specific mission phase description as the input driver and uses a high granularity database to produce a multi-orbit power system performance report. The EPS model accurately predicts the power system response to various mission timelines over the entire operational life of the spacecraft.

  12. Multiple system modelling of waste management

    SciTech Connect

    Eriksson, Ola; Bisaillon, Mattias

    2011-12-15

    Highlights: > Linking of models will provide a more complete, correct and credible picture of the systems. > The linking procedure is easy to perform and also leads to activation of project partners. > The simulation procedure is a bit more complicated and calls for the ability to run both models. - Abstract: Due to increased environmental awareness, planning and performance of waste management has become more and more complex. Therefore waste management has early been subject to different types of modelling. Another field with long experience of modelling and systems perspective is energy systems. The two modelling traditions have developed side by side, but so far there are very few attempts to combine them. Waste management systems can be linked together with energy systems through incineration plants. The models for waste management can be modelled on a quite detailed level whereas surrounding systems are modelled in a more simplistic way. This is a problem, as previous studies have shown that assumptions on the surrounding system often tend to be important for the conclusions. In this paper it is shown how two models, one for the district heating system (MARTES) and another one for the waste management system (ORWARE), can be linked together. The strengths and weaknesses with model linking are discussed when compared to simplistic assumptions on effects in the energy and waste management systems. It is concluded that the linking of models will provide a more complete, correct and credible picture of the consequences of different simultaneous changes in the systems. The linking procedure is easy to perform and also leads to activation of project partners. However, the simulation procedure is a bit more complicated and calls for the ability to run both models.

  13. Modeling of power electronic systems with EMTP

    NASA Technical Reports Server (NTRS)

    Tam, Kwa-Sur; Dravid, Narayan V.

    1989-01-01

    In view of the potential impact of power electronics on power systems, there is need for a computer modeling/analysis tool to perform simulation studies on power systems with power electronic components as well as to educate engineering students about such systems. The modeling of the major power electronic components of the NASA Space Station Freedom Electric Power System is described along with ElectroMagnetic Transients Program (EMTP) and it is demonstrated that EMTP can serve as a very useful tool for teaching, design, analysis, and research in the area of power systems with power electronic components. EMTP modeling of power electronic circuits is described and simulation results are presented.

  14. DAIS Models Simulation System (DMSS)

    NASA Astrophysics Data System (ADS)

    Brewer, A. C.

    1981-05-01

    The DMSS software support effort enhanced the capabilities and value of DMSS by accomplishing the following four objectives: (1) Addition of VATS/Pave Tack and Maverick Missile models; (2) Enhancing the existing software; (3) Creating meaningful, up-to-date documentation; and (4) Providing comprehensive training. The new models were developed using top-down structuring techniques and were implemented in RATFOR (a structured FORTRAN preprocessor). The existing models were restructured using top-down structuring techniques, RATFOR, and meaningful comments. The documentation was updated to adhere to MIL-STD-483 and 490.

  15. Very Large System Dynamics Models - Lessons Learned

    SciTech Connect

    Jacob J. Jacobson; Leonard Malczynski

    2008-10-01

    This paper provides lessons learned from developing several large system dynamics (SD) models. System dynamics modeling practice emphasize the need to keep models small so that they are manageable and understandable. This practice is generally reasonable and prudent; however, there are times that large SD models are necessary. This paper outlines two large SD projects that were done at two Department of Energy National Laboratories, the Idaho National Laboratory and Sandia National Laboratories. This paper summarizes the models and then discusses some of the valuable lessons learned during these two modeling efforts.

  16. Modeling of the DZero data acquisition system

    SciTech Connect

    Angstadt, R.; Johnson, M.; Manning, I.L. ); Wightman, J.A. . Dept. of Physics Texas Accelerator Center, The Woodlands, TX )

    1991-12-01

    A queuing theory model was used in the initial design of the D0 data acquisition system. It was mainly used for the front end electronic systems. Since then the model has been extended to include the entire data path for the tracking system. The tracking system generates the most data so we expect this system to determine the overall transfer rate. The model was developed using both analytical and simulation methods for solving a series of single server queues. We describe the model and the methods used to develop it. We also present results from the original models, updated calculations representing the system as built and comparisons with measurements made with the hardware in place for the cosmic ray test run. 3 refs.

  17. Precipitation-runoff modeling system; user's manual

    USGS Publications Warehouse

    Leavesley, G.H.; Lichty, R.W.; Troutman, B.M.; Saindon, L.G.

    1983-01-01

    The concepts, structure, theoretical development, and data requirements of the precipitation-runoff modeling system (PRMS) are described. The precipitation-runoff modeling system is a modular-design, deterministic, distributed-parameter modeling system developed to evaluate the impacts of various combinations of precipitation, climate, and land use on streamflow, sediment yields, and general basin hydrology. Basin response to normal and extreme rainfall and snowmelt can be simulated to evaluate changes in water balance relationships, flow regimes, flood peaks and volumes, soil-water relationships, sediment yields, and groundwater recharge. Parameter-optimization and sensitivity analysis capabilites are provided to fit selected model parameters and evaluate their individual and joint effects on model output. The modular design provides a flexible framework for continued model system enhancement and hydrologic modeling research and development. (Author 's abstract)

  18. Information modeling system for blast furnace control

    NASA Astrophysics Data System (ADS)

    Spirin, N. A.; Gileva, L. Y.; Lavrov, V. V.

    2016-09-01

    Modern Iron & Steel Works as a rule are equipped with powerful distributed control systems (DCS) and databases. Implementation of DSC system solves the problem of storage, control, protection, entry, editing and retrieving of information as well as generation of required reporting data. The most advanced and promising approach is to use decision support information technologies based on a complex of mathematical models. The model decision support system for control of blast furnace smelting is designed and operated. The basis of the model system is a complex of mathematical models created using the principle of natural mathematical modeling. This principle provides for construction of mathematical models of two levels. The first level model is a basic state model which makes it possible to assess the vector of system parameters using field data and blast furnace operation results. It is also used to calculate the adjustment (adaptation) coefficients of the predictive block of the system. The second-level model is a predictive model designed to assess the design parameters of the blast furnace process when there are changes in melting conditions relative to its current state. Tasks for which software is developed are described. Characteristics of the main subsystems of the blast furnace process as an object of modeling and control - thermal state of the furnace, blast, gas dynamic and slag conditions of blast furnace smelting - are presented.

  19. Stirling System Modeling for Space Nuclear Power Systems

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Johnson, Paul K.

    2007-01-01

    A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.

  20. Stirling System Modeling for Space Nuclear Power Systems

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Johnson, Paul K.

    2008-01-01

    A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power, and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.

  1. Systems Modeling in Developmental Toxicity

    EPA Science Inventory

    An individual starts off as a single cell, the progeny of which form complex structures that are themselves integrated into progressively larger systems. Developmental biology is concerned with how this cellular complexity and patterning arises through orchestration of cell divi...

  2. NASA Glenn Wind Tunnel Model Systems Criteria

    NASA Technical Reports Server (NTRS)

    Soeder, Ronald H.; Roeder, James W.; Stark, David E.; Linne, Alan A.

    2004-01-01

    This report describes criteria for the design, analysis, quality assurance, and documentation of models that are to be tested in the wind tunnel facilities at the NASA Glenn Research Center. This report presents two methods for computing model allowable stresses on the basis of the yield stress or ultimate stress, and it defines project procedures to test models in the NASA Glenn aeropropulsion facilities. Both customer-furnished and in-house model systems are discussed. The functions of the facility personnel and customers are defined. The format for the pretest meetings, safety permit process, and model reviews are outlined. The format for the model systems report (a requirement for each model that is to be tested at NASA Glenn) is described, the engineers responsible for developing the model systems report are listed, and the timetable for its delivery to the project engineer is given.

  3. System Advisor Model: Flat Plate Photovoltaic Performance Modeling Validation Report

    SciTech Connect

    Freeman, J.; Whitmore, J.; Kaffine, L.; Blair, N.; Dobos, A. P.

    2013-12-01

    The System Advisor Model (SAM) is a free software tool that performs detailed analysis of both system performance and system financing for a variety of renewable energy technologies. This report provides detailed validation of the SAM flat plate photovoltaic performance model by comparing SAM-modeled PV system generation data to actual measured production data for nine PV systems ranging from 75 kW to greater than 25 MW in size. The results show strong agreement between SAM predictions and field data, with annualized prediction error below 3% for all fixed tilt cases and below 8% for all one axis tracked cases. The analysis concludes that snow cover and system outages are the primary sources of disagreement, and other deviations resulting from seasonal biases in the irradiation models and one axis tracking issues are discussed in detail.

  4. UNCERTAIN SYSTEM MODELING OF SNS RF CONTROL SYSTEM

    SciTech Connect

    S. KWON; A. REGAN; ET AL

    2001-06-01

    This paper addresses the modeling problem of the linear accelerator RF system for SNS. The cascade of the klystron and the cavity is modeled as a nominal system. In the real world, high voltage power supply ripple, Lorentz Force Detuning, microphonics, cavity RF parameter perturbations, distortions in RF components, and loop time delay imperfection exist inevitably, which must be analyzed. The analysis is based on the accurate modeling of the disturbances and uncertainties. In this paper, a modern control theory is applied for modeling the disturbances, uncertainties, and for analyzing the closed loop system robust performance.

  5. MODEL VERSION CONTROL FOR GREAT LAKES MODELS ON UNIX SYSTEMS

    EPA Science Inventory

    Scientific results of the Lake Michigan Mass Balance Project were provided where atrazine was measured and modeled. The presentation also provided the model version control system which has been used for models at Grosse Ile for approximately a decade and contains various version...

  6. Modeling Cytoskeletal Active Matter Systems

    NASA Astrophysics Data System (ADS)

    Blackwell, Robert

    Active networks of filamentous proteins and crosslinking motor proteins play a critical role in many important cellular processes. One of the most important microtubule-motor protein assemblies is the mitotic spindle, a self-organized active liquid-crystalline structure that forms during cell division and that ultimately separates chromosomes into two daughter cells. Although the spindle has been intensively studied for decades, the physical principles that govern its self-organization and function remain mysterious. To evolve a better understanding of spindle formation, structure, and dynamics, I investigate course-grained models of active liquid-crystalline networks composed of microtubules, modeled as hard spherocylinders, in diffusive equilibrium with a reservoir of active crosslinks, modeled as hookean springs that can adsorb to microtubules and and translocate at finite velocity along the microtubule axis. This model is investigated using a combination of brownian dynamics and kinetic monte carlo simulation. I have further refined this model to simulate spindle formation and kinetochore capture in the fission yeast S. pombe. I then make predictions for experimentally realizable perturbations in motor protein presence and function in S. pombe.

  7. 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.

  8. Solids modeller to drafting system transfer program

    SciTech Connect

    Robbins, D.

    1983-03-01

    A Solids Modeller in use at Sandia National Laboratories (Albuquerque), PADL2 has been interfaced to a Turnkey Drafting System, Applicon. This interface permits design at the high level of the Solids Modeller with dimensioning and drawing production at the turnkey drafting system.

  9. NEMS - National Energy Modeling System: An Overview

    EIA Publications

    2009-01-01

    The National Energy Modeling System: An Overview 2009 a summary description of NEMS and each of its components. NEMS is a computer-based, energy-economy modeling system of energy markets for the midterm period through 2030. The NEMS is used to produce the Annual Energy Outlook.

  10. Comprehensive system models: Strategies for evaluation

    NASA Technical Reports Server (NTRS)

    Field, Christopher; Kutzbach, John E.; Ramanathan, V.; Maccracken, Michael C.

    1992-01-01

    The task of evaluating comprehensive earth system models is vast involving validations of every model component at every scale of organization, as well as tests of all the individual linkages. Even the most detailed evaluation of each of the component processes and the individual links among them should not, however, engender confidence in the performance of the whole. The integrated earth system is so rich with complex feedback loops, often involving components of the atmosphere, oceans, biosphere, and cryosphere, that it is certain to exhibit emergent properties very difficult to predict from the perspective of a narrow focus on any individual component of the system. Therefore, a substantial share of the task of evaluating comprehensive earth system models must reside at the level of whole system evaluations. Since complete, integrated atmosphere/ ocean/ biosphere/ hydrology models are not yet operational, questions of evaluation must be addressed at the level of the kinds of earth system processes that the models should be competent to simulate, rather than at the level of specific performance criteria. Here, we have tried to identify examples of earth system processes that are difficult to simulate with existing models and that involve a rich enough suite of feedbacks that they are unlikely to be satisfactorily described by highly simplified or toy models. Our purpose is not to specify a checklist of evaluation criteria but to introduce characteristics of the earth system that may present useful opportunities for model testing and, of course, improvement.

  11. CONCEPTUAL MODELS FOR THE LASSEN HYDROTHERMAL SYSTEM.

    USGS Publications Warehouse

    Ingebritsen, S.E.; Sorey, M.L.

    1987-01-01

    The Lassen hydrothermal system, like a number of other systems in regions of moderate to great topographic relief, includes steam-heated features at higher elevations and high-chloride springs at lower elevations, connected to and fed by a single circulation system at depth. Two conceptual models for such systems are presented. They are similar in several ways: however, there are basic differences in terms of the nature and extent of vapor-dominated conditions beneath the steam-heated features. For some Lassen-like systems, these differences could have environmental and economic implications. Available data do not make it possible to establish a single preferred model for the Lassen system, and the actual system is complex enough that both models may apply to different parts of the system.

  12. Reliability modelling for non-electronic systems

    NASA Astrophysics Data System (ADS)

    Valisena, N.; Demollerat, T.

    An approach for reliability modeling of nonelectronic systems is presented. The need for a specific methodology to be applied in the nonelectronic area is justified because nonelectronic items are generally single point failure of the system, and the classical approach used in electronics cannot be realistically applied to nonelectronic items, due to their particularities. Specific models, depending on both design margins and provisions for realization aspects, are proposed. Examples of such models and rules of combination of the models at system level are given. The results of research conducted on typical probabilities in the space area for human errors and inspection efficiencies are presented.

  13. Thruster models for NEP system analysis

    NASA Technical Reports Server (NTRS)

    Gilland, Jim

    1993-01-01

    There are currently no thruster modeling codes that can be integrated with power system codes for full propulsion system modeling. Most existing thruster models were written from a 'stand alone' viewpoint, assuming the user is performing analyses on thruster performance alone. The goal of the present modeling effort is to develop thruster codes that model performance and scaling as a function of mission and system inputs, rather than in terms of more elemental physical parameters. System level parameters of interest are as follows: performance, such as specific impulse and efficency; terminal characteristics, such as voltage or current; and mass. Specific impulse and efficiency couple with mission analyses, while terminal characteristics allow integration with power systems. Additional information on lifetime and operation may be required for detailed designs.

  14. Mathematical Modeling Of Life-Support Systems

    NASA Technical Reports Server (NTRS)

    Seshan, Panchalam K.; Ganapathi, Balasubramanian; Jan, Darrell L.; Ferrall, Joseph F.; Rohatgi, Naresh K.

    1994-01-01

    Generic hierarchical model of life-support system developed to facilitate comparisons of options in design of system. Model represents combinations of interdependent subsystems supporting microbes, plants, fish, and land animals (including humans). Generic model enables rapid configuration of variety of specific life support component models for tradeoff studies culminating in single system design. Enables rapid evaluation of effects of substituting alternate technologies and even entire groups of technologies and subsystems. Used to synthesize and analyze life-support systems ranging from relatively simple, nonregenerative units like aquariums to complex closed-loop systems aboard submarines or spacecraft. Model, called Generic Modular Flow Schematic (GMFS), coded in such chemical-process-simulation languages as Aspen Plus and expressed as three-dimensional spreadsheet.

  15. A Mathematical Model for Railway Control Systems

    NASA Technical Reports Server (NTRS)

    Hoover, D. N.

    1996-01-01

    We present a general method for modeling safety aspects of railway control systems. Using our modeling method, one can progressively refine an abstract railway safety model, sucessively adding layers of detail about how a real system actually operates, while maintaining a safety property that refines the original abstract safety property. This method supports a top-down approach to specification of railway control systems and to proof of a variety of safety-related properties. We demonstrate our method by proving safety of the classical block control system.

  16. 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.

  17. Moving from basic toward systems pharmacodynamic models.

    PubMed

    Jusko, William J

    2013-09-01

    Building upon many classical foundations of pharmacology, a diverse array of mechanistic pharmacokinetic-pharmacodynamic (PK/PD) models have emerged based on mechanisms of drug action and primary rate-limiting or turnover processes in physiology. An array of basic models can be extended to handle various complexities including tolerance and can readily be employed as building blocks in assembling enhanced PK/PD or small systems models. Our corticosteroid models demonstrate these concepts as well as elements of horizontal and vertical integration of molecular to whole-body processes. The potential advantages and challenges in moving PK/PD toward systems models are described.

  18. A Conceptual Data Model of Datum Systems

    PubMed Central

    McCaleb, Michael R.

    1999-01-01

    A new conceptual data model that addresses the geometric dimensioning and tolerancing concepts of datum systems, datums, datum features, datum targets, and the relationships among these concepts, is presented. Additionally, a portion of a related data model, Part 47 of STEP (ISO 10303-47), is reviewed and a comparison is made between it and the new conceptual data model.

  19. A model for international border management systems.

    SciTech Connect

    Duggan, Ruth Ann

    2008-09-01

    To effectively manage the security or control of its borders, a country must understand its border management activities as a system. Using its systems engineering and security foundations as a Department of Energy National Security Laboratory, Sandia National Laboratories has developed such an approach to modeling and analyzing border management systems. This paper describes the basic model and its elements developed under Laboratory Directed Research and Development project 08-684.

  20. Cognitive engineering models in space systems

    NASA Technical Reports Server (NTRS)

    Mitchell, Christine M.

    1992-01-01

    NASA space systems, including mission operations on the ground and in space, are complex, dynamic, predominantly automated systems in which the human operator is a supervisory controller. The human operator monitors and fine-tunes computer-based control systems and is responsible for ensuring safe and efficient system operation. In such systems, the potential consequences of human mistakes and errors may be very large, and low probability of such events is likely. Thus, models of cognitive functions in complex systems are needed to describe human performance and form the theoretical basis of operator workstation design, including displays, controls, and decision support aids. The operator function model represents normative operator behavior-expected operator activities given current system state. The extension of the theoretical structure of the operator function model and its application to NASA Johnson mission operations and space station applications is discussed.

  1. Human performance modeling for system of systems analytics.

    SciTech Connect

    Dixon, Kevin R.; Lawton, Craig R.; Basilico, Justin Derrick; Longsine, Dennis E.; Forsythe, James Chris; Gauthier, John Henry; Le, Hai D.

    2008-10-01

    A Laboratory-Directed Research and Development project was initiated in 2005 to investigate Human Performance Modeling in a System of Systems analytic environment. SAND2006-6569 and SAND2006-7911 document interim results from this effort; this report documents the final results. The problem is difficult because of the number of humans involved in a System of Systems environment and the generally poorly defined nature of the tasks that each human must perform. A two-pronged strategy was followed: one prong was to develop human models using a probability-based method similar to that first developed for relatively well-understood probability based performance modeling; another prong was to investigate more state-of-art human cognition models. The probability-based modeling resulted in a comprehensive addition of human-modeling capability to the existing SoSAT computer program. The cognitive modeling resulted in an increased understanding of what is necessary to incorporate cognition-based models to a System of Systems analytic environment.

  2. 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.…

  3. Farming Systems Modeling Using the Object Modeling System (OMS): Overview, Applications, and Future Plans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of the Object Modeling System (OMS) modeling framework represents a comprehensive partnership between the USDA ARS/NRCS, USGS, and university collaborators. OMS helps streamline the development of integrated farming system models for current and future model delivery using a component-or...

  4. Modeling Arctic Climate with a Regional Arctic System Model (RASM)

    NASA Astrophysics Data System (ADS)

    Cassano, J. J.; Duvivier, A.; Hughes, M.; Roberts, A.; Brunke, M.; Fisel, B. J.; Gutowski, W. J.; Maslowski, W.; Nijssen, B.; Osinski, R.; Zeng, X.

    2013-12-01

    A new regional Earth system model of the Arctic, the Regional Arctic System Model (RASM), has recently been developed. The initial version of this model includes atmosphere (WRF), ocean (POP), sea ice (CICE), and land (VIC) component models coupled with the NCAR CESM CPL7 coupler. The model is configured to run on a large pan-Arctic domain that includes all sea ice covered waters in the Northern Hemisphere and all Arctic Ocean draining land areas. Results from multi-decadal (1989 to present) simulations with RASM will be presented and will focus on the model's representation of atmosphere, ocean, sea ice, and land surface climate, emphasizing both strengths and weaknesses of the current model climate and comparisons with atmosphere-only WRF simulations. Results from the model show both areas of improvement and degraded results relative to stand-alone WRF. Improvement in the coupled model climate are related to more physically realistic representation of coupled processes such as energy transfer from the ocean to the atmosphere through leads in the sea ice during winter. Degraded results come from feedbacks in model component biases, such as atmospheric circulation biases resulting in incorrect local sea ice cover that then result in large local atmospheric temperature biases. The issue of spectral nudging in a coupled regional climate model system as well as other lessons learned during the development of RASM will be discussed. The presentation will conclude with future plans for RASM.

  5. The UK Earth System Model project

    NASA Astrophysics Data System (ADS)

    Tang, Yongming

    2016-04-01

    In this talk we will describe the development and current status of the UK Earth System Model (UKESM). This project is a NERC/Met Office collaboration and has two objectives; to develop and apply a world-leading Earth System Model, and to grow a community of UK Earth System Model scientists. We are building numerical models that include all the key components of the global climate system, and contain the important process interactions between global biogeochemistry, atmospheric chemistry and the physical climate system. UKESM will be used to make key CMIP6 simulations as well as long-time (e.g. millennium) simulations, large ensemble experiments and investigating a range of future carbon emission scenarios.

  6. How nontraditional model systems can save us

    PubMed Central

    Gladfelter, Amy S.

    2015-01-01

    In this essay I would like to highlight how work in nontraditional model systems is an imperative for our society to prepare for problems we do not even know exist. I present examples of how discovery in nontraditional systems has been critical for fundamental advancement in cell biology. I also discuss how as a collective we might harvest both new questions and new solutions to old problems from the underexplored reservoir of diversity in the biosphere. With advancements in genomics, proteomics, and genome editing, it is now technically feasible for even a single research group to introduce a new model system. I aim here to inspire people to think beyond their familiar model systems and to press funding agencies to support the establishment of new model systems. PMID:26515971

  7. Requirements based system risk modeling

    NASA Technical Reports Server (NTRS)

    Meshkat, Leila; Cornford, Steven; Feather, Martin

    2004-01-01

    The problem that we address in this paper is assessing the expected degree of success of the system or mission based on the degree to which each requirement is satisfied and the relative weight of the requirements. We assume a complete list of the requirements, the relevant risk elements and their probability of occurrence and the quantified effect of the risk elements on the requirements. In order to assess the degree to which each requirement is satisfied, we need to determine the effect of the various risk elements on the requirement.

  8. Structural system identification: Structural dynamics model validation

    SciTech Connect

    Red-Horse, J.R.

    1997-04-01

    Structural system identification is concerned with the development of systematic procedures and tools for developing predictive analytical models based on a physical structure`s dynamic response characteristics. It is a multidisciplinary process that involves the ability (1) to define high fidelity physics-based analysis models, (2) to acquire accurate test-derived information for physical specimens using diagnostic experiments, (3) to validate the numerical simulation model by reconciling differences that inevitably exist between the analysis model and the experimental data, and (4) to quantify uncertainties in the final system models and subsequent numerical simulations. The goal of this project was to develop structural system identification techniques and software suitable for both research and production applications in code and model validation.

  9. Plasmids as stochastic model systems

    NASA Astrophysics Data System (ADS)

    Paulsson, Johan

    2003-05-01

    Plasmids are self-replicating gene clusters present in on average 2-100 copies per bacterial cell. To reduce random fluctuations and thereby avoid extinction, they ubiquitously autoregulate their own synthesis using negative feedback loops. Here I use van Kampen's Ω-expansion for a two-dimensional model of negative feedback including plasmids and ther replication inhibitors. This analytically summarizes the standard perspective on replication control -- including the effects of sensitivity amplification, exponential time-delays and noisy signaling. I further review the two most common molecular sensitivity mechanisms: multistep control and cooperativity. Finally, I discuss more controversial sensitivity schemes, such as noise-enhanced sensitivity, the exploitation of small-number combinatorics and double-layered feedback loops to suppress noise in disordered environments.

  10. Development and Integration of Control System Models

    NASA Technical Reports Server (NTRS)

    Kim, Young K.

    1998-01-01

    The computer simulation tool, TREETOPS, has been upgraded and used at NASA/MSFC to model various complicated mechanical systems and to perform their dynamics and control analysis with pointing control systems. A TREETOPS model of Advanced X-ray Astrophysics Facility - Imaging (AXAF-1) dynamics and control system was developed to evaluate the AXAF-I pointing performance for Normal Pointing Mode. An optical model of Shooting Star Experiment (SSE) was also developed and its optical performance analysis was done using the MACOS software.

  11. Geographic information system/watershed model interface

    USGS Publications Warehouse

    Fisher, Gary T.

    1989-01-01

    Geographic information systems allow for the interactive analysis of spatial data related to water-resources investigations. A conceptual design for an interface between a geographic information system and a watershed model includes functions for the estimation of model parameter values. Design criteria include ease of use, minimal equipment requirements, a generic data-base management system, and use of a macro language. An application is demonstrated for a 90.1-square-kilometer subbasin of the Patuxent River near Unity, Maryland, that performs automated derivation of watershed parameters for hydrologic modeling.

  12. Modeling Multi-Arc Spraying Systems

    NASA Astrophysics Data System (ADS)

    Bobzin, K.; Öte, M.

    2016-06-01

    The use of plasma as energy source in thermal spraying enables among others the processing of feed stock materials with very high melting temperatures as coating materials. New generation multi-arc plasma spraying systems are widely spread and promise several advantages in comparison to the conventional single-arc systems. Numerical modeling of multi-arc plasma spraying offers the possibility to increase the understanding about this process. This study focuses on the numerical modeling of three-cathode spraying systems, introducing the recent activities in this field and discussing the numerical aspects which influence the prediction power of the models.

  13. Models And Results Database System.

    2001-03-27

    Version 00 MAR-D 4.16 is a program that is used primarily for Probabilistic Risk Assessment (PRA) data loading. This program defines a common relational database structure that is used by other PRA programs. This structure allows all of the software to access and manipulate data created by other software in the system without performing a lengthy conversion. The MAR-D program also provides the facilities for loading and unloading of PRA data from the relational databasemore » structure used to store the data to an ASCII format for interchange with other PRA software. The primary function of MAR-D is to create a data repository for NUREG-1150 and other permanent data by providing input, conversion, and output capabilities for data used by IRRAS, SARA, SETS and FRANTIC.« less

  14. System monitoring and diagnosis with qualitative models

    NASA Technical Reports Server (NTRS)

    Kuipers, Benjamin

    1991-01-01

    A substantial foundation of tools for model-based reasoning with incomplete knowledge was developed: QSIM (a qualitative simulation program) and its extensions for qualitative simulation; Q2, Q3 and their successors for quantitative reasoning on a qualitative framework; and the CC (component-connection) and QPC (Qualitative Process Theory) model compilers for building QSIM QDE (qualitative differential equation) models starting from different ontological assumptions. Other model-compilers for QDE's, e.g., using bond graphs or compartmental models, have been developed elsewhere. These model-building tools will support automatic construction of qualitative models from physical specifications, and further research into selection of appropriate modeling viewpoints. For monitoring and diagnosis, plausible hypotheses are unified against observations to strengthen or refute the predicted behaviors. In MIMIC (Model Integration via Mesh Interpolation Coefficients), multiple hypothesized models of the system are tracked in parallel in order to reduce the 'missing model' problem. Each model begins as a qualitative model, and is unified with a priori quantitative knowledge and with the stream of incoming observational data. When the model/data unification yields a contradiction, the model is refuted. When there is no contradiction, the predictions of the model are progressively strengthened, for use in procedure planning and differential diagnosis. Only under a qualitative level of description can a finite set of models guarantee the complete coverage necessary for this performance. The results of this research are presented in several publications. Abstracts of these published papers are presented along with abtracts of papers representing work that was synergistic with the NASA grant but funded otherwise. These 28 papers include but are not limited to: 'Combined qualitative and numerical simulation with Q3'; 'Comparative analysis and qualitative integral representations

  15. Hypersonic Vehicle Propulsion System Simplified Model Development

    NASA Technical Reports Server (NTRS)

    Stueber, Thomas J.; Raitano, Paul; Le, Dzu K.; Ouzts, Peter

    2007-01-01

    This document addresses the modeling task plan for the hypersonic GN&C GRC team members. The overall propulsion system modeling task plan is a multi-step process and the task plan identified in this document addresses the first steps (short term modeling goals). The procedures and tools produced from this effort will be useful for creating simplified dynamic models applicable to a hypersonic vehicle propulsion system. The document continues with the GRC short term modeling goal. Next, a general description of the desired simplified model is presented along with simulations that are available to varying degrees. The simulations may be available in electronic form (FORTRAN, CFD, MatLab,...) or in paper form in published documents. Finally, roadmaps outlining possible avenues towards realizing simplified model are presented.

  16. Modeling system for conducted transient analysis

    SciTech Connect

    Mahoney, T.L.

    1983-01-01

    A computer simulation system has been developed which facilitates the analysis of electrical/electronic systems. Sponsored by the Naval Air Systems Command to investigate power interface transient problems, the program is called the Navy Power Systems Simulator. The simulator is used as a system engineering tool which generates and processes models of virtually any electrical network. It is simple to use and capable of automatically producing a complex system's steady state or transient output response. An engineering friendly computer interface has been achieved by the extensive use of interactive graphics and menu-driven prompting.

  17. Virtual modelling of compartmental pharmacokinetic systems.

    PubMed

    Prado, Manuel; Roa, Laura

    2005-01-01

    This paper presents an analysis of different methodologies for modelling pharmacokinetic systems under the context of a telemedicine system oriented to the on-line and personalized knowledge generation. We use a simplified 3-pool kinetic system for a better clarification of several relevant modelling formalisms. A more complete 3-pool urea kinetic model is built simply connecting EL components pertaining to a pharmacokinetic library previously developed. The evolution of the urea concentration during the dialysis of a patient provided by this model was compared successfully to the evolution computed by a 2-pool model experimentally validated. The 3-pool model provides more information regarding the interstice and a high capacity to be modified for attending to the knowledge needs of physicians, as well as biomedicine advances. As a major conclusion, our outcomes suggest that virtual modelling is an excellent methodology in biomedical engineering to support the on-line generation of personalized health knowledge for telemedicine systems. This is due to its capacity for reusing components at horizontal and vertical level, and for implementing multiformalism and multidomain models, what simplifies the task to represent complex physiological and artificial systems. PMID:17282097

  18. Photovoltaic System Modeling. Uncertainty and Sensitivity Analyses

    SciTech Connect

    Hansen, Clifford W.; Martin, Curtis E.

    2015-08-01

    We report an uncertainty and sensitivity analysis for modeling AC energy from ph otovoltaic systems . Output from a PV system is predicted by a sequence of models. We quantify u ncertainty i n the output of each model using empirical distribution s of each model's residuals. We propagate uncertainty through the sequence of models by sampli ng these distributions to obtain a n empirical distribution of a PV system's output. We consider models that: (1) translate measured global horizontal, direct and global diffuse irradiance to plane - of - array irradiance; (2) estimate effective irradiance; (3) predict cell temperature; (4) estimate DC voltage, current and power ; (5) reduce DC power for losses due to inefficient maximum power point tracking or mismatch among modules; and (6) convert DC to AC power . O ur analysis consider s a notional PV system com prising an array of FirstSolar FS - 387 modules and a 250 kW AC inverter ; we use measured irradiance and weather at Albuquerque, NM. We found the uncertainty in PV syste m output to be relatively small, on the order of 1% for daily energy. We found that unce rtainty in the models for POA irradiance and effective irradiance to be the dominant contributors to uncertainty in predicted daily energy. Our analysis indicates that efforts to reduce the uncertainty in PV system output predictions may yield the greatest improvements by focusing on the POA and effective irradiance models.

  19. Climate Model Diagnostic Analyzer Web Service System

    NASA Astrophysics Data System (ADS)

    Lee, S.; Pan, L.; Zhai, C.; Tang, B.; Kubar, T. L.; Li, J.; Zhang, J.; Wang, W.

    2015-12-01

    Both the National Research Council Decadal Survey and the latest Intergovernmental Panel on Climate Change Assessment Report stressed the need for the comprehensive and innovative evaluation of climate models with the synergistic use of global satellite observations in order to improve our weather and climate simulation and prediction capabilities. The abundance of satellite observations for fundamental climate parameters and the availability of coordinated model outputs from CMIP5 for the same parameters offer a great opportunity to understand and diagnose model biases in climate models. In addition, the Obs4MIPs efforts have created several key global observational datasets that are readily usable for model evaluations. However, a model diagnostic evaluation process requires physics-based multi-variable comparisons that typically involve large-volume and heterogeneous datasets, making them both computationally- and data-intensive. In response, we have developed a novel methodology to diagnose model biases in contemporary climate models and implementing the methodology as a web-service based, cloud-enabled, provenance-supported climate-model evaluation system. The evaluation system is named Climate Model Diagnostic Analyzer (CMDA), which is the product of the research and technology development investments of several current and past NASA ROSES programs. The current technologies and infrastructure of CMDA are designed and selected to address several technical challenges that the Earth science modeling and model analysis community faces in evaluating and diagnosing climate models. In particular, we have three key technology components: (1) diagnostic analysis methodology; (2) web-service based, cloud-enabled technology; (3) provenance-supported technology. The diagnostic analysis methodology includes random forest feature importance ranking, conditional probability distribution function, conditional sampling, and time-lagged correlation map. We have implemented the

  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. Model verification of large structural systems. [space shuttle model response

    NASA Technical Reports Server (NTRS)

    Lee, L. T.; Hasselman, T. K.

    1978-01-01

    A computer program for the application of parameter identification on the structural dynamic models of space shuttle and other large models with hundreds of degrees of freedom is described. Finite element, dynamic, analytic, and modal models are used to represent the structural system. The interface with math models is such that output from any structural analysis program applied to any structural configuration can be used directly. Processed data from either sine-sweep tests or resonant dwell tests are directly usable. The program uses measured modal data to condition the prior analystic model so as to improve the frequency match between model and test. A Bayesian estimator generates an improved analytical model and a linear estimator is used in an iterative fashion on highly nonlinear equations. Mass and stiffness scaling parameters are generated for an improved finite element model, and the optimum set of parameters is obtained in one step.

  2. Rethinking modeling framework design: object modeling system 3.0

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Object Modeling System (OMS) is a framework for environmental model development, data provisioning, testing, validation, and deployment. It provides a bridge for transferring technology from the research organization to the program delivery agency. The framework provides a consistent and efficie...

  3. CTBT integrated verification system evaluation model supplement

    SciTech Connect

    EDENBURN,MICHAEL W.; BUNTING,MARCUS; PAYNE JR.,ARTHUR C.; TROST,LAWRENCE C.

    2000-03-02

    Sandia National Laboratories has developed a computer based model called IVSEM (Integrated Verification System Evaluation Model) to estimate the performance of a nuclear detonation monitoring system. The IVSEM project was initiated in June 1994, by Sandia's Monitoring Systems and Technology Center and has been funded by the U.S. Department of Energy's Office of Nonproliferation and National Security (DOE/NN). IVSEM is a simple, ''top-level,'' modeling tool which estimates the performance of a Comprehensive Nuclear Test Ban Treaty (CTBT) monitoring system and can help explore the impact of various sensor system concepts and technology advancements on CTBT monitoring. One of IVSEM's unique features is that it integrates results from the various CTBT sensor technologies (seismic, in sound, radionuclide, and hydroacoustic) and allows the user to investigate synergy among the technologies. Specifically, IVSEM estimates the detection effectiveness (probability of detection), location accuracy, and identification capability of the integrated system and of each technology subsystem individually. The model attempts to accurately estimate the monitoring system's performance at medium interfaces (air-land, air-water) and for some evasive testing methods such as seismic decoupling. The original IVSEM report, CTBT Integrated Verification System Evaluation Model, SAND97-25 18, described version 1.2 of IVSEM. This report describes the changes made to IVSEM version 1.2 and the addition of identification capability estimates that have been incorporated into IVSEM version 2.0.

  4. Propulsion System Models for Rotorcraft Conceptual Design

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2014-01-01

    The conceptual design code NDARC (NASA Design and Analysis of Rotorcraft) was initially implemented to model conventional rotorcraft propulsion systems, consisting of turboshaft engines burning jet fuel, connected to one or more rotors through a mechanical transmission. The NDARC propulsion system representation has been extended to cover additional propulsion concepts, including electric motors and generators, rotor reaction drive, turbojet and turbofan engines, fuel cells and solar cells, batteries, and fuel (energy) used without weight change. The paper describes these propulsion system components, the architecture of their implementation in NDARC, and the form of the models for performance and weight. Requirements are defined for improved performance and weight models of the new propulsion system components. With these new propulsion models, NDARC can be used to develop environmentally-friendly rotorcraft designs.

  5. A Telecommunications Industry Primer: A Systems Model.

    ERIC Educational Resources Information Center

    Obermier, Timothy R.; Tuttle, Ronald H.

    2003-01-01

    Describes the Telecommunications Systems Model to help technical educators and students understand the increasingly complex telecommunications infrastructure. Specifically looks at ownership and regulatory status, service providers, transport medium, network protocols, and end-user services. (JOW)

  6. Constructing minimal models for complex system dynamics

    NASA Astrophysics Data System (ADS)

    Barzel, Baruch; Liu, Yang-Yu; Barabási, Albert-László

    2015-05-01

    One of the strengths of statistical physics is the ability to reduce macroscopic observations into microscopic models, offering a mechanistic description of a system's dynamics. This paradigm, rooted in Boltzmann's gas theory, has found applications from magnetic phenomena to subcellular processes and epidemic spreading. Yet, each of these advances were the result of decades of meticulous model building and validation, which are impossible to replicate in most complex biological, social or technological systems that lack accurate microscopic models. Here we develop a method to infer the microscopic dynamics of a complex system from observations of its response to external perturbations, allowing us to construct the most general class of nonlinear pairwise dynamics that are guaranteed to recover the observed behaviour. The result, which we test against both numerical and empirical data, is an effective dynamic model that can predict the system's behaviour and provide crucial insights into its inner workings.

  7. Spinal Cord Injury Model System Information Network

    MedlinePlus

    ... the UAB-SCIMS More The UAB-SCIMS Information Network The University of Alabama at Birmingham Spinal Cord Injury Model System (UAB-SCIMS) maintains this Information Network as a resource to promote knowledge in the ...

  8. Systemic Therapy: A New Brief Intervention Model.

    ERIC Educational Resources Information Center

    Searight, H. Russell; Openlander, Patrick

    1984-01-01

    Describes a newly developing mode of problem-oriented brief therapy. The systemic therapy model emphasizes the interactional context of clients' problems and represents an efficient intervention paradigm. (Author/JAC)

  9. Modeling Web-Based Educational Systems: Process Design Teaching Model

    ERIC Educational Resources Information Center

    Rokou, Franca Pantano; Rokou, Elena; Rokos, Yannis

    2004-01-01

    Using modeling languages is essential to the construction of educational systems based on software engineering principles and methods. Furthermore, the instructional design is undoubtedly the cornerstone of the design and development of educational systems. Although several methodologies and languages have been proposed for the specification of…

  10. On Roles of Models in Information Systems

    NASA Astrophysics Data System (ADS)

    Sølvberg, Arne

    The increasing penetration of computers into all aspects of human activity makes it desirable that the interplay among software, data and the domains where computers are applied is made more transparent. An approach to this end is to explicitly relate the modeling concepts of the domains, e.g., natural science, technology and business, to the modeling concepts of software and data. This may make it simpler to build comprehensible integrated models of the interactions between computers and non-computers, e.g., interaction among computers, people, physical processes, biological processes, and administrative processes. This chapter contains an analysis of various facets of the modeling environment for information systems engineering. The lack of satisfactory conceptual modeling tools seems to be central to the unsatisfactory state-of-the-art in establishing information systems. The chapter contains a proposal for defining a concept of information that is relevant to information systems engineering.

  11. The Modular Modeling System (MMS): User's Manual

    USGS Publications Warehouse

    Leavesley, G.H.; Restrepo, P.J.; Markstrom, S.L.; Dixon, M.; Stannard, L.G.

    1996-01-01

    The Modular Modeling System (MMS) is an integrated system of computer software that has been developed to provide the research and operational framework needed to support development, testing, and evaluation of physical-process algorithms and to facilitate integration of user-selected sets of algorithms into operational physical-process models. MMS uses a module library that contains modules for simulating a variety of water, energy, and biogeochemical processes. A model is created by selectively coupling the most appropriate modules from the library to create a 'suitable' model for the desired application. Where existing modules do not provide appropriate process algorithms, new modules can be developed. The MMS user's manual provides installation instructions and a detailed discussion of system concepts, module development, and model development and application using the MMS graphical user interface.

  12. An EHF telecommunication system engineering model

    NASA Astrophysics Data System (ADS)

    Allen, Kenneth C.

    1987-11-01

    An extremely high frequency telecommunication system engineering model (ETSEM) was developed as an aid in the design of line-of-sight (LOS) communication systems from 10 to 100 GHz. ETSEM provides tabulation of path geometry parameters and analyzes ray path and Fresnel zone clearances to help the engineer design the path. ETSEM also predicts the performance (availability) of both digital and analog systems based on state-of-the-art EHF propagation models and equipment specifications. Attenuation by rain, clear air absorption and multipath are modeled. These are expected essentially to determine the statistics of link availability as limited by propagation impairments. Performance may be predicted by any interval of months of the year. A climatological data base for North America and Europe provides parameters for the propagation models. ETSEM has been implemented on a desk top computer. Weaknesses and limitations of the model are discussed.

  13. Multiscale Computational Models of Complex Biological Systems

    PubMed Central

    Walpole, Joseph; Papin, Jason A.; Peirce, Shayn M.

    2014-01-01

    Integration of data across spatial, temporal, and functional scales is a primary focus of biomedical engineering efforts. The advent of powerful computing platforms, coupled with quantitative data from high-throughput experimental platforms, has allowed multiscale modeling to expand as a means to more comprehensively investigate biological phenomena in experimentally relevant ways. This review aims to highlight recently published multiscale models of biological systems while using their successes to propose the best practices for future model development. We demonstrate that coupling continuous and discrete systems best captures biological information across spatial scales by selecting modeling techniques that are suited to the task. Further, we suggest how to best leverage these multiscale models to gain insight into biological systems using quantitative, biomedical engineering methods to analyze data in non-intuitive ways. These topics are discussed with a focus on the future of the field, the current challenges encountered, and opportunities yet to be realized. PMID:23642247

  14. System model development for nuclear thermal propulsion

    SciTech Connect

    Walton, J.T.; Hannan, N.A.; Perkins, K.R.; Buksa, J.J.; Worley, B.A.; Dobranich, D.

    1992-10-01

    A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. Since October 1991, US (DOE), (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review. The vision and strategy of the interagency team for developing NTP system models will be discussed in this paper. A review of the progress on the Level 1 interagency model is also presented.

  15. Hybrid Energy System Modeling in Modelica

    SciTech Connect

    William R. Binder; Christiaan J. J. Paredis; Humberto E. Garcia

    2014-03-01

    In this paper, a Hybrid Energy System (HES) configuration is modeled in Modelica. Hybrid Energy Systems (HES) have as their defining characteristic the use of one or more energy inputs, combined with the potential for multiple energy outputs. Compared to traditional energy systems, HES provide additional operational flexibility so that high variability in both energy production and consumption levels can be absorbed more effectively. This is particularly important when including renewable energy sources, whose output levels are inherently variable, determined by nature. The specific HES configuration modeled in this paper include two energy inputs: a nuclear plant, and a series of wind turbines. In addition, the system produces two energy outputs: electricity and synthetic fuel. The models are verified through simulations of the individual components, and the system as a whole. The simulations are performed for a range of component sizes, operating conditions, and control schemes.

  16. An ecological process model of systems change.

    PubMed

    Peirson, Leslea J; Boydell, Katherine M; Ferguson, H Bruce; Ferris, Lorraine E

    2011-06-01

    In June 2007 the American Journal of Community Psychology published a special issue focused on theories, methods and interventions for systems change which included calls from the editors and authors for theoretical advancement in this field. We propose a conceptual model of systems change that integrates familiar and fundamental community psychology principles (succession, interdependence, cycling of resources, adaptation) and accentuates a process orientation. To situate our framework we offer a definition of systems change and a brief review of the ecological perspective and principles. The Ecological Process Model of Systems Change is depicted, described and applied to a case example of policy driven systems level change in publicly funded social programs. We conclude by identifying salient implications for thinking and action which flow from the Model. PMID:21203829

  17. A Hierarchical Systems Approach to Model Validation

    NASA Astrophysics Data System (ADS)

    Easterbrook, S. M.

    2011-12-01

    Existing approaches to the question of how climate models should be evaluated tend to rely on either philosophical arguments about the status of models as scientific tools, or on empirical arguments about how well runs from a given model match observational data. These have led to quantitative approaches expressed in terms of model bias or forecast skill, and ensemble approaches where models are assessed according to the extent to which the ensemble brackets the observational data. Unfortunately, such approaches focus the evaluation on models per se (or more specifically, on the simulation runs they produce) as though the models can be isolated from their context. Such approach may overlook a number of important aspects of the use of climate models: - the process by which models are selected and configured for a given scientific question. - the process by which model outputs are selected, aggregated and interpreted by a community of expertise in climatology. - the software fidelity of the models (i.e. whether the running code is actually doing what the modellers think it's doing). - the (often convoluted) history that begat a given model, along with the modelling choices long embedded in the code. - variability in the scientific maturity of different model components within a coupled system. These omissions mean that quantitative approaches cannot assess whether a model produces the right results for the wrong reasons, or conversely, the wrong results for the right reasons (where, say the observational data is problematic, or the model is configured to be unlike the earth system for a specific reason). Hence, we argue that it is a mistake to think that validation is a post-hoc process to be applied to an individual "finished" model, to ensure it meets some criteria for fidelity to the real world. We are therefore developing a framework for model validation that extends current approaches down into the detailed codebase and the processes by which the code is built

  18. Modeling, system identification, and control of ASTREX

    NASA Technical Reports Server (NTRS)

    Abhyankar, Nandu S.; Ramakrishnan, J.; Byun, K. W.; Das, A.; Cossey, Derek F.; Berg, J.

    1993-01-01

    The modeling, system identification and controller design aspects of the ASTREX precision space structure are presented in this work. Modeling of ASTREX is performed using NASTRAN, TREETOPS and I-DEAS. The models generated range from simple linear time-invariant models to nonlinear models used for large angle simulations. Identification in both the time and frequency domains are presented. The experimental set up and the results from the identification experiments are included. Finally, controller design for ASTREX is presented. Simulation results using this optimal controller demonstrate the controller performance. Finally the future directions and plans for the facility are addressed.

  19. Modeling, system identification, and control of ASTREX

    NASA Astrophysics Data System (ADS)

    Abhyankar, Nandu S.; Ramakrishnan, J.; Byun, K. W.; Das, A.; Cossey, Derek F.; Berg, J.

    1993-02-01

    The modeling, system identification and controller design aspects of the ASTREX precision space structure are presented in this work. Modeling of ASTREX is performed using NASTRAN, TREETOPS and I-DEAS. The models generated range from simple linear time-invariant models to nonlinear models used for large angle simulations. Identification in both the time and frequency domains are presented. The experimental set up and the results from the identification experiments are included. Finally, controller design for ASTREX is presented. Simulation results using this optimal controller demonstrate the controller performance. Finally the future directions and plans for the facility are addressed.

  20. The National Energy Modeling System: An overview

    SciTech Connect

    Not Available

    1994-05-01

    The National Energy Modeling System (NEMS) is a computer-based, energy-economy modeling system of US energy markets for the midterm period of 1990 to 2010. NEMS projects the production, imports, conversion, consumption, and prices of energy, subject to assumptions on macroeconomic and financial factors, world energy markets, resource availability and costs, behavioral and technological choice criteria, cost and performance characteristics of energy technologies, and demographics. This report presents an overview of the structure and methodology of NEMS and each of its components. The first chapter provides a description of the design and objectives of the system. The second chapter describes the modeling structure. The remainder of the report summarizes the methodology and scope of the component modules of NEMS. The model descriptions are intended for readers familiar with terminology from economics, operations research, and energy modeling. Additional background on the development of the system is provided in Appendix A of this report, which describes the EIA modeling systems that preceded NEMS. More detailed model documentation reports for all the NEMS modules are also available from EIA.

  1. Stirling Convertor System Dynamic Model Developed

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Regan, Timothy F.

    2005-01-01

    Free-piston Stirling convertors are being developed for potential use on NASA exploration missions. In support of this effort, the NASA Glenn Research Center has developed the Stirling convertor System Dynamic Model (SDM). The SDM models the Stirling cycle thermodynamics; heat flow; gas, mechanical, and mounting dynamics; the linear alternator; and the controller. The SDM s scope extends from the thermal energy input to thermal, mechanical, and electrical energy output, allowing one to study complex system interactions among subsystems. Thermal, mechanical, fluid, magnetic, and electrical subsystems can be studied in one model. The SDM is a nonlinear time-domain model containing sub-cycle dynamics, which simulates transient and dynamic phenomena that other models cannot. The entire range of convertor operation is modeled, from startup to full-power conditions.

  2. The Colorado Scale-Model Solar System.

    ERIC Educational Resources Information Center

    Bennett, Jeffrey O.; And Others

    1991-01-01

    Describes the Colorado Scale-Model Solar System, a display illustrating the sizes and distances to the Sun and the nine planets on the campus of Colorado University. Discusses the model's educational value and uses for the classroom and the community. (MDH)

  3. On modeling and controlling intelligent systems

    SciTech Connect

    Dress, W.B.

    1993-11-01

    The aim of this paper is to show how certain diverse and advanced techniques of information processing and system theory might be integrated into a model of an intelligent, complex entity capable of materially enhancing an advanced information management system. To this end, we first examine the notion of intelligence and ask whether a semblance thereof can arise in a system consisting of ensembles of finite-state automata. Our goal is to find a functional model of intelligence in an information-management setting that can be used as a tool. The purpose of this tool is to allow us to create systems of increasing complexity and utility, eventually reaching the goal of an intelligent information management system that provides and anticipates needed data and information. We base our attempt on the ideas of general system theory where the four topics of system identification, modeling, optimization, and control provide the theoretical framework for constructing a complex system that will be capable of interacting with complex systems in the real world. These four key topics are discussed within the purview of cellular automata, neural networks, and evolutionary programming. This is a report of ongoing work, and not yet a success story of a synthetic intelligent system.

  4. Human performance modeling for system of systems analytics :soldier fatigue.

    SciTech Connect

    Lawton, Craig R.; Campbell, James E.; Miller, Dwight Peter

    2005-10-01

    The military has identified Human Performance Modeling (HPM) as a significant requirement and challenge of future systems modeling and analysis initiatives as can be seen in the Department of Defense's (DoD) Defense Modeling and Simulation Office's (DMSO) Master Plan (DoD 5000.59-P 1995). To this goal, the military is currently spending millions of dollars on programs devoted to HPM in various military contexts. Examples include the Human Performance Modeling Integration (HPMI) program within the Air Force Research Laboratory, which focuses on integrating HPMs with constructive models of systems (e.g. cockpit simulations) and the Navy's Human Performance Center (HPC) established in September 2003. Nearly all of these initiatives focus on the interface between humans and a single system. This is insufficient in the era of highly complex network centric SoS. This report presents research and development in the area of HPM in a system-of-systems (SoS). Specifically, this report addresses modeling soldier fatigue and the potential impacts soldier fatigue can have on SoS performance.

  5. OFFl Models: Novel Schema for Dynamical Modeling of Biological Systems.

    PubMed

    Ogbunugafor, C Brandon; Robinson, Sean P

    2016-01-01

    Flow diagrams are a common tool used to help build and interpret models of dynamical systems, often in biological contexts such as consumer-resource models and similar compartmental models. Typically, their usage is intuitive and informal. Here, we present a formalized version of flow diagrams as a kind of weighted directed graph which follow a strict grammar, which translate into a system of ordinary differential equations (ODEs) by a single unambiguous rule, and which have an equivalent representation as a relational database. (We abbreviate this schema of "ODEs and formalized flow diagrams" as OFFL.) Drawing a diagram within this strict grammar encourages a mental discipline on the part of the modeler in which all dynamical processes of a system are thought of as interactions between dynamical species that draw parcels from one or more source species and deposit them into target species according to a set of transformation rules. From these rules, the net rate of change for each species can be derived. The modeling schema can therefore be understood as both an epistemic and practical heuristic for modeling, serving both as an organizational framework for the model building process and as a mechanism for deriving ODEs. All steps of the schema beyond the initial scientific (intuitive, creative) abstraction of natural observations into model variables are algorithmic and easily carried out by a computer, thus enabling the future development of a dedicated software implementation. Such tools would empower the modeler to consider significantly more complex models than practical limitations might have otherwise proscribed, since the modeling framework itself manages that complexity on the modeler's behalf. In this report, we describe the chief motivations for OFFL, carefully outline its implementation, and utilize a range of classic examples from ecology and epidemiology to showcase its features. PMID:27270918

  6. OFFl Models: Novel Schema for Dynamical Modeling of Biological Systems.

    PubMed

    Ogbunugafor, C Brandon; Robinson, Sean P

    2016-01-01

    Flow diagrams are a common tool used to help build and interpret models of dynamical systems, often in biological contexts such as consumer-resource models and similar compartmental models. Typically, their usage is intuitive and informal. Here, we present a formalized version of flow diagrams as a kind of weighted directed graph which follow a strict grammar, which translate into a system of ordinary differential equations (ODEs) by a single unambiguous rule, and which have an equivalent representation as a relational database. (We abbreviate this schema of "ODEs and formalized flow diagrams" as OFFL.) Drawing a diagram within this strict grammar encourages a mental discipline on the part of the modeler in which all dynamical processes of a system are thought of as interactions between dynamical species that draw parcels from one or more source species and deposit them into target species according to a set of transformation rules. From these rules, the net rate of change for each species can be derived. The modeling schema can therefore be understood as both an epistemic and practical heuristic for modeling, serving both as an organizational framework for the model building process and as a mechanism for deriving ODEs. All steps of the schema beyond the initial scientific (intuitive, creative) abstraction of natural observations into model variables are algorithmic and easily carried out by a computer, thus enabling the future development of a dedicated software implementation. Such tools would empower the modeler to consider significantly more complex models than practical limitations might have otherwise proscribed, since the modeling framework itself manages that complexity on the modeler's behalf. In this report, we describe the chief motivations for OFFL, carefully outline its implementation, and utilize a range of classic examples from ecology and epidemiology to showcase its features.

  7. Modelling the Shuttle Remote Manipulator System: Another flexible model

    NASA Technical Reports Server (NTRS)

    Barhorst, Alan A.

    1993-01-01

    High fidelity elastic system modeling algorithms are discussed. The particular system studied is the Space Shuttle Remote Manipulator System (RMS) undergoing full articulated motion. The model incorporates flexibility via a methodology the author has been developing. The technique is based in variational principles, so rigorous boundary condition generation and weak formulations for the associated partial differential equations are realized, yet the analyst need not integrate by parts. The methodology is formulated using vector-dyad notation with minimal use of tensor notation, therefore the technique is believed to be affable to practicing engineers. The objectives of this work are as follows: (1) determine the efficacy of the modeling method; and (2) determine if the method affords an analyst advantages in the overall modeling and simulation task. Generated out of necessity were Mathematica algorithms that quasi-automate the modeling procedure and simulation development. The project was divided into sections as follows: (1) model development of a simplified manipulator; (2) model development of the full-freedom RMS including a flexible movable base on a six degree of freedom orbiter (a rigid-body is attached to the manipulator end-effector); (3) simulation development for item 2; and (4) comparison to the currently used model of the flexible RMS in the Structures and Mechanics Division of NASA JSC. At the time of the writing of this report, items 3 and 4 above were not complete.

  8. World energy projection system: Model documentation

    NASA Astrophysics Data System (ADS)

    1992-06-01

    The World Energy Project System (WEPS) is an accounting framework that incorporates projects from independently documented models and assumptions about the future energy intensity of economic activity (ratios of total energy consumption divided by gross domestic product) and about the rate of incremental energy requirements met by hydropower, geothermal, coal, and natural gas to produce projections of world energy consumption published annually by the Energy Information Administration (EIA) in the International Energy Outlook (IEO). Two independently documented models presented in Figure 1, the Oil Market Simulation (OMS) model and the World Integrated Nuclear Evaluation System (WINES), provide projections of oil and nuclear power consumption published in the IEO. Output from a third independently documented model, and the International Coal Trade Model (ICTM), is not published in the IEO but is used in WEPS as a supply check on projections of world coal consumption produced by WEPS and published in the IEO. A WEPS model of natural gas production documented in this report provides the same type of implicit supply check on the WEPS projections of world natural gas consumption published in the IEO. Two additional models are included in Figure 1, the OPEC Capacity model and the Non-OPEC Oil Production model. These WEPS models provide inputs to the OMS model and are documented in this report.

  9. The Satellite System: A Model for Deinstitutionalization.

    ERIC Educational Resources Information Center

    Boyan, Craig

    The paper presents the community-based satellite system as a residential and program model to effect deinstitutionalization of mentally retarded young adults in urban centers worldwide. The system is reported to consist of a large, central educational facility surrounded by a series of small houses and apartment units (satellites). Benefits of…

  10. CTBT Integrated Verification System Evaluation Model

    SciTech Connect

    Edenburn, M.W.; Bunting, M.L.; Payne, A.C. Jr.

    1997-10-01

    Sandia National Laboratories has developed a computer based model called IVSEM (Integrated Verification System Evaluation Model) to estimate the performance of a nuclear detonation monitoring system. The IVSEM project was initiated in June 1994, by Sandia`s Monitoring Systems and Technology Center and has been funded by the US Department of Energy`s Office of Nonproliferation and National Security (DOE/NN). IVSEM is a simple, top-level, modeling tool which estimates the performance of a Comprehensive Nuclear Test Ban Treaty (CTBT) monitoring system and can help explore the impact of various sensor system concepts and technology advancements on CTBT monitoring. One of IVSEM`s unique features is that it integrates results from the various CTBT sensor technologies (seismic, infrasound, radionuclide, and hydroacoustic) and allows the user to investigate synergy among the technologies. Specifically, IVSEM estimates the detection effectiveness (probability of detection) and location accuracy of the integrated system and of each technology subsystem individually. The model attempts to accurately estimate the monitoring system`s performance at medium interfaces (air-land, air-water) and for some evasive testing methods such as seismic decoupling. This report describes version 1.2 of IVSEM.

  11. A Fuzzy Model of Document Retrieval Systems

    ERIC Educational Resources Information Center

    Tahani, Valiollah

    1976-01-01

    This paper is concerned with the organization and retrieval of records in document retrieval systems which admit of imprecision in the form of fuzziness in document characterization and retrieval rules. A mathematical model for such systems, based on the theory of fuzzy sets, is introduced. (Author)

  12. Modeling a Longitudinal Relational Research Data Systems

    ERIC Educational Resources Information Center

    Olsen, Michelle D. Hunt

    2010-01-01

    A study was conducted to propose a research-based model for a longitudinal data research system that addressed recommendations from a synthesis of literature related to: (1) needs reported by the U.S. Department of Education, (2) the twelve mandatory elements that define federally approved state longitudinal data systems (SLDS), (3) the…

  13. Cost and Performance Model for Photovoltaic Systems

    NASA Technical Reports Server (NTRS)

    Borden, C. S.; Smith, J. H.; Davisson, M. C.; Reiter, L. J.

    1986-01-01

    Lifetime cost and performance (LCP) model assists in assessment of design options for photovoltaic systems. LCP is simulation of performance, cost, and revenue streams associated with photovoltaic power systems connected to electric-utility grid. LCP provides user with substantial flexibility in specifying technical and economic environment of application.

  14. Space Power System Modeling with EBAL

    SciTech Connect

    Zillmer, Andrew; Hanks, David; Wen-Hsiung 'Tony' Tu

    2006-07-01

    Pratt and Whitney Rocket dyne's Engine Balance (EBAL) thermal/fluid system code has been expanded to model nuclear power closed Brayton cycle (CBC) power conversion systems. EBAL was originally developed to perform design analysis of hypersonic vehicle propellant and thermal management systems analysis. Later, it was adapted to rocket engine cycles. The new version of EBAL includes detailed, physics-based models of all key CBC system components. Some component examples are turbo-alternators, heat exchangers, heat pipe radiators, and liquid metal pumps. A liquid metal cooled reactor is included and a gas cooled reactor model is in work. Both thermodynamic and structural analyses are performed for each component. EBAL performs steady-state design analysis with optimization as well as off-design performance analysis. Design optimization is performed both at the component level by the component models and on the system level with a global optimizer. The user has the option to manually drive the optimization process or run parametric analysis to better understand system trade-off. Although recent EBAL developments have focused on a CBC conversion system, the code is easily extendible to other power conversion cycles. This new, more powerful version of EBAL allows for rapid design analysis and optimization of space power systems. A notional example of EBAL's capabilities is included. (authors)

  15. Eclectic Model in the Malaysian Education System

    ERIC Educational Resources Information Center

    Othman, Nooraini; Mohamad, Khairul Azmi; Ilmuwan, Yayasan

    2011-01-01

    The present work aims at analysing the adoption of eclectic model in the Malaysian education system. The analysis is specifically looked from the angle of Islam and the Muslims. Malaysia has a long history of education system developments, from pre to post independence of the country. From what was initially traditional, modernity later came to…

  16. Chain modeling for life cycle systems engineering

    SciTech Connect

    Rivera, J.J.; Shapiro, V.

    1997-12-01

    Throughout Sandia`s history, products have been represented by drawings. Solid modeling systems have recently replaced drawings as the preferred means for representing product geometry. These systems are used for product visualization, engineering analysis and manufacturing planning. Unfortunately, solid modeling technology is inadequate for life cycle systems engineering, which requires maintenance of technical history, efficient management of geometric and non-geometric data, and explicit representation of engineering and manufacturing characteristics. Such information is not part of the mathematical foundation of solid modeling. The current state-of-the-art in life cycle engineering is comprised of painstakingly created special purpose tools, which often are incompatible. New research on {open_quotes}chain modeling{close_quotes} provides a method of chaining the functionality of a part to the geometric representation. Chain modeling extends classical solid modeling to include physical, manufacturing, and procedural information required for life cycle engineering. In addition, chain modeling promises to provide the missing theoretical basis for Sandia`s parent/child product realization paradigm. In chain modeling, artifacts and systems are characterized in terms of their combinatorial properties: cell complexes, chains, and their operators. This approach is firmly rooted in algebraic topology and is a natural extension of current technology. The potential benefits of this approach include explicit hierarchical and combinatorial representation of physics, geometry, functionality, test, and legacy data in a common computational framework that supports a rational decision process and partial design automation. Chain modeling will have a significant impact on design preservation, system identification, parameterization, system reliability, and design simplification.

  17. Degradation Modelling for Health Monitoring Systems

    NASA Astrophysics Data System (ADS)

    Stetter, R.; Witczak, M.

    2014-12-01

    Condition-monitoring plays an increasingly important role for technical processes in order to improve reliability, availability, maintenance and lifetime of equipment. With increasing demands for efficiency and product quality, plus progress in the integration of automatic control systems in high-cost mechatronic and critical safety processes, the field of health monitoring is gaining interest. A similar research field is concerned with an estimation of the remaining useful life. A central question in these fields is the modelling of degradation; degradation is a process of a gradual and irreversible accumulation of damage which will finally result in a failure of the system. This paper is based on a current research project and explores various degradation modelling techniques. These results are explained on the basis of an industrial product - a system for the generation of health status information for pump systems. The result of this fuzzy-logic based system is a single number indicating the current health of a pump system.

  18. Systemic change increases model projection uncertainty

    NASA Astrophysics Data System (ADS)

    Verstegen, Judith; Karssenberg, Derek; van der Hilst, Floor; Faaij, André

    2014-05-01

    Most spatio-temporal models are based on the assumption that the relationship between system state change and its explanatory processes is stationary. This means that model structure and parameterization are usually kept constant over time, ignoring potential systemic changes in this relationship resulting from e.g., climatic or societal changes, thereby overlooking a source of uncertainty. We define systemic change as a change in the system indicated by a system state change that cannot be simulated using a constant model structure. We have developed a method to detect systemic change, using a Bayesian data assimilation technique, the particle filter. The particle filter was used to update the prior knowledge about the model structure. In contrast to the traditional particle filter approach (e.g., Verstegen et al., 2014), we apply the filter separately for each point in time for which observations are available, obtaining the optimal model structure for each of the time periods in between. This allows us to create a time series of the evolution of the model structure. The Runs test (Wald and Wolfowitz, 1940), a stationarity test, is used to check whether variation in this time series can be attributed to randomness or not. If not, this indicates systemic change. The uncertainty that the systemic change adds to the existing model projection uncertainty can be determined by comparing model outcomes of a model with a stationary model structure and a model with a model structure changing according to the variation found in the time series. To test the systemic change detection methodology, we apply it to a land use change cellular automaton (CA) (Verstegen et al., 2012) and use observations of real land use from all years from 2004 to 2012 and associated uncertainty as observational data in the particle filter. A systemic change was detected for the period 2006 to 2008. In this period the influence on the location of sugar cane expansion of the driver sugar cane in

  19. Engine Structures Modeling Software System (ESMOSS)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Engine Structures Modeling Software System (ESMOSS) is the development of a specialized software system for the construction of geometric descriptive and discrete analytical models of engine parts, components, and substructures which can be transferred to finite element analysis programs such as NASTRAN. The NASA Lewis Engine Structures Program is concerned with the development of technology for the rational structural design and analysis of advanced gas turbine engines with emphasis on advanced structural analysis, structural dynamics, structural aspects of aeroelasticity, and life prediction. Fundamental and common to all of these developments is the need for geometric and analytical model descriptions at various engine assembly levels which are generated using ESMOSS.

  20. Modelling the crop: from system dynamics to systems biology.

    PubMed

    Yin, Xinyou; Struik, Paul C

    2010-05-01

    There is strong interplant competition in a crop stand for various limiting resources, resulting in complex compensation and regulation mechanisms along the developmental cascade of the whole crop. Despite decades-long use of principles in system dynamics (e.g. feedback control), current crop models often contain many empirical elements, and model parameters may have little biological meaning. Building on the experience in designing the relatively new model GECROS, we believe models can be made less empirical by employing existing physiological understanding and mathematical tools. In view of the potential added value of robust crop modelling to classical quantitative genetics, model input parameters are increasingly considered to represent 'genetic coefficients'. The advent of functional genomics and systems biology enables the elucidation of the molecular genetic basis of these coefficients. A number of case studies, in which the effects of quantitative trait loci or genes have been incorporated into existing ecophysiological models, have shown the promise of using models in analysing genotype-phenotype relationships of some crop traits. For further progress, crop models must be upgraded based on understanding at lower organizational levels for complicated phenomena such as sink formation in response to environmental cues, sink feedback on source activity, and photosynthetic acclimation to the prevailing environment. Within this context, the recently proposed 'crop systems biology', which combines modern genomics, traditional physiology and biochemistry, and advanced modelling, is believed ultimately to realize the expected roles of in silico modelling in narrowing genotype-phenotype gaps. This review summarizes recent findings and our opinions on perspectives for modelling genotype x environment interactions at crop level. PMID:20051352

  1. Efficient dynamic models of tensegrity systems

    NASA Astrophysics Data System (ADS)

    Skelton, Robert

    2009-03-01

    The multi-body dynamics appear in a new form, as a matrix differential equation, rather than the traditional vector differential equation. The model has a constant mass matrix, and the equations are non-minimal. A specific focus of this paper is tensegrity systems. A tensegrity system requires prestress for stabilization of the configuration of rigid bodies and tensile members. This paper provides an efficient model for both static and dynamic behavior of such systems, specialized for the case when the rigid bodies are axi-symmetric rods.

  2. Mass storage system reference model, Version 4

    NASA Technical Reports Server (NTRS)

    Coleman, Sam (Editor); Miller, Steve (Editor)

    1993-01-01

    The high-level abstractions that underlie modern storage systems are identified. The information to generate the model was collected from major practitioners who have built and operated large storage facilities, and represents a distillation of the wisdom they have acquired over the years. The model provides a common terminology and set of concepts to allow existing systems to be examined and new systems to be discussed and built. It is intended that the model and the interfaces identified from it will allow and encourage vendors to develop mutually-compatible storage components that can be combined to form integrated storage systems and services. The reference model presents an abstract view of the concepts and organization of storage systems. From this abstraction will come the identification of the interfaces and modules that will be used in IEEE storage system standards. The model is not yet suitable as a standard; it does not contain implementation decisions, such as how abstract objects should be broken up into software modules or how software modules should be mapped to hosts; it does not give policy specifications, such as when files should be migrated; does not describe how the abstract objects should be used or connected; and does not refer to specific hardware components. In particular, it does not fully specify the interfaces.

  3. Nonlinear model for building-soil systems

    SciTech Connect

    McCallen, D.B.; Romstad, K.M.

    1994-05-01

    A finite-element based, numerical analysis methodology has been developed for the nonlinear analysis of building-soil systems. The methodology utilizes a reduced-order, nonlinear continuum model to represent the building, and the soil is represented with a simple nonlinear two-dimensional plane strain finite element. The foundation of the building is idealized as a rigid block and the interface between the soil and the foundation is modeled with an interface contract element. The objectives of the current paper are to provide the theoretical development of the system model, with particular emphasis on the modeling of the foundation-soil contact, and to demonstrate the special-purpose finite-element program that has been developed for nonlinear analysis of the building-soil system. Examples are included that compare the results obtained with the special-purpose program with the results of a general-purpose nonlinear finite-element program.

  4. OFFl Models: Novel Schema for Dynamical Modeling of Biological Systems

    PubMed Central

    2016-01-01

    Flow diagrams are a common tool used to help build and interpret models of dynamical systems, often in biological contexts such as consumer-resource models and similar compartmental models. Typically, their usage is intuitive and informal. Here, we present a formalized version of flow diagrams as a kind of weighted directed graph which follow a strict grammar, which translate into a system of ordinary differential equations (ODEs) by a single unambiguous rule, and which have an equivalent representation as a relational database. (We abbreviate this schema of “ODEs and formalized flow diagrams” as OFFL.) Drawing a diagram within this strict grammar encourages a mental discipline on the part of the modeler in which all dynamical processes of a system are thought of as interactions between dynamical species that draw parcels from one or more source species and deposit them into target species according to a set of transformation rules. From these rules, the net rate of change for each species can be derived. The modeling schema can therefore be understood as both an epistemic and practical heuristic for modeling, serving both as an organizational framework for the model building process and as a mechanism for deriving ODEs. All steps of the schema beyond the initial scientific (intuitive, creative) abstraction of natural observations into model variables are algorithmic and easily carried out by a computer, thus enabling the future development of a dedicated software implementation. Such tools would empower the modeler to consider significantly more complex models than practical limitations might have otherwise proscribed, since the modeling framework itself manages that complexity on the modeler’s behalf. In this report, we describe the chief motivations for OFFL, carefully outline its implementation, and utilize a range of classic examples from ecology and epidemiology to showcase its features. PMID:27270918

  5. System model development for nuclear thermal propulsion

    SciTech Connect

    Hannan, N.A.; Worley, B.A.; Walton, J.T.; Perkins, K.R.; Buksa, J.J.; Dobranich, D.

    1992-11-01

    A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. This is crucial for mission analysis and for control subsystem testing as well as for the modeling of various failure modes. Performance must be accurately predicted during steady-state and transient operation, including startup, shutdown and post operation cooling. The development and application of verified and validated system models has the potential to reduce the design, testing, cost and time required for the technology to reach flight-ready status. Since October 1991, the US Department of Energy (DOE), Department of Defense (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling.

  6. Model Based Testing for Agent Systems

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiyong; Thangarajah, John; Padgham, Lin

    Although agent technology is gaining world wide popularity, a hindrance to its uptake is the lack of proper testing mechanisms for agent based systems. While many traditional software testing methods can be generalized to agent systems, there are many aspects that are different and which require an understanding of the underlying agent paradigm. In this paper we present certain aspects of a testing framework that we have developed for agent based systems. The testing framework is a model based approach using the design models of the Prometheus agent development methodology. In this paper we focus on model based unit testing and identify the appropriate units, present mechanisms for generating suitable test cases and for determining the order in which the units are to be tested, present a brief overview of the unit testing process and an example. Although we use the design artefacts from Prometheus the approach is suitable for any plan and event based agent system.

  7. Summary of photovoltaic system performance models

    NASA Technical Reports Server (NTRS)

    Smith, J. H.; Reiter, L. J.

    1984-01-01

    A detailed overview of photovoltaics (PV) performance modeling capabilities developed for analyzing PV system and component design and policy issues is provided. A set of 10 performance models are selected which span a representative range of capabilities from generalized first order calculations to highly specialized electrical network simulations. A set of performance modeling topics and characteristics is defined and used to examine some of the major issues associated with photovoltaic performance modeling. Each of the models is described in the context of these topics and characteristics to assess its purpose, approach, and level of detail. The issues are discussed in terms of the range of model capabilities available and summarized in tabular form for quick reference. The models are grouped into categories to illustrate their purposes and perspectives.

  8. Summary of photovoltaic system performance models

    SciTech Connect

    Smith, J. H.; Reiter, L. J.

    1984-01-15

    The purpose of this study is to provide a detailed overview of photovoltaics (PV) performance modeling capabilities that have been developed during recent years for analyzing PV system and component design and policy issues. A set of 10 performance models have been selected which span a representative range of capabilities from generalized first-order calculations to highly specialized electrical network simulations. A set of performance modeling topics and characteristics is defined and used to examine some of the major issues associated with photovoltaic performance modeling. Next, each of the models is described in the context of these topics and characteristics to assess its purpose, approach, and level of detail. Then each of the issues is discussed in terms of the range of model capabilities available and summarized in tabular form for quick reference. Finally, the models are grouped into categories to illustrate their purposes and perspectives.

  9. Mathematical models for space shuttle ground systems

    NASA Technical Reports Server (NTRS)

    Tory, E. G.

    1985-01-01

    Math models are a series of algorithms, comprised of algebraic equations and Boolean Logic. At Kennedy Space Center, math models for the Space Shuttle Systems are performed utilizing the Honeywell 66/80 digital computers, Modcomp II/45 Minicomputers and special purpose hardware simulators (MicroComputers). The Shuttle Ground Operations Simulator operating system provides the language formats, subroutines, queueing schemes, execution modes and support software to write, maintain and execute the models. The ground systems presented consist primarily of the Liquid Oxygen and Liquid Hydrogen Cryogenic Propellant Systems, as well as liquid oxygen External Tank Gaseous Oxygen Vent Hood/Arm and the Vehicle Assembly Building (VAB) High Bay Cells. The purpose of math modeling is to simulate the ground hardware systems and to provide an environment for testing in a benign mode. This capability allows the engineers to check out application software for loading and launching the vehicle, and to verify the Checkout, Control, & Monitor Subsystem within the Launch Processing System. It is also used to train operators and to predict system response and status in various configurations (normal operations, emergency and contingent operations), including untried configurations or those too dangerous to try under real conditions, i.e., failure modes.

  10. Hot Water Distribution System Model Enhancements

    SciTech Connect

    Hoeschele, M.; Weitzel, E.

    2012-11-01

    This project involves enhancement of the HWSIM distribution system model to more accurately model pipe heat transfer. Recent laboratory testing efforts have indicated that the modeling of radiant heat transfer effects is needed to accurately characterize piping heat loss. An analytical methodology for integrating radiant heat transfer was implemented with HWSIM. Laboratory test data collected in another project was then used to validate the model for a variety of uninsulated and insulated pipe cases (copper, PEX, and CPVC). Results appear favorable, with typical deviations from lab results less than 8%.

  11. Intrinsic Uncertainties in Modeling Complex Systems.

    SciTech Connect

    Cooper, Curtis S; Bramson, Aaron L.; Ames, Arlo L.

    2014-09-01

    Models are built to understand and predict the behaviors of both natural and artificial systems. Because it is always necessary to abstract away aspects of any non-trivial system being modeled, we know models can potentially leave out important, even critical elements. This reality of the modeling enterprise forces us to consider the prospective impacts of those effects completely left out of a model - either intentionally or unconsidered. Insensitivity to new structure is an indication of diminishing returns. In this work, we represent a hypothetical unknown effect on a validated model as a finite perturba- tion whose amplitude is constrained within a control region. We find robustly that without further constraints, no meaningful bounds can be placed on the amplitude of a perturbation outside of the control region. Thus, forecasting into unsampled regions is a very risky proposition. We also present inherent difficulties with proper time discretization of models and representing in- herently discrete quantities. We point out potentially worrisome uncertainties, arising from math- ematical formulation alone, which modelers can inadvertently introduce into models of complex systems. Acknowledgements This work has been funded under early-career LDRD project #170979, entitled "Quantify- ing Confidence in Complex Systems Models Having Structural Uncertainties", which ran from 04/2013 to 09/2014. We wish to express our gratitude to the many researchers at Sandia who con- tributed ideas to this work, as well as feedback on the manuscript. In particular, we would like to mention George Barr, Alexander Outkin, Walt Beyeler, Eric Vugrin, and Laura Swiler for provid- ing invaluable advice and guidance through the course of the project. We would also like to thank Steven Kleban, Amanda Gonzales, Trevor Manzanares, and Sarah Burwell for their assistance in managing project tasks and resources.

  12. A digital video model deformation system

    NASA Technical Reports Server (NTRS)

    Burner, A. W.; Snow, W. L.; Goad, W. K.; Childers, B. A.

    1987-01-01

    The use of solid-state array cameras and a PC-controlled image acquisition system to measure model deformation in a wind tunnel is discussed. This digital system improves an earlier video model deformation system that used high-resolution tube cameras and required the manual measurement of targets on video hardcopy images. The new system eliminates both the vibration-induced distortion associated with tube cameras and the manual readup of video images necessary in the earlier version. Camera calibration and data reduction procedures necessary to convert pixel image plane data from two cameras into wing deflections are presented. Laboratory tests to establish the uncertainty of the system with the geometry to be used are described.

  13. In-Space Chemical Propulsion System Model

    NASA Technical Reports Server (NTRS)

    Byers, David C.; Woodcock, Gordon; Benfield, Michael P. J.

    2004-01-01

    Multiple, new technologies for chemical systems are becoming available and include high temperature rockets, very light propellant tanks and structures, new bipropellant and monopropellant options, lower mass propellant control components, and zero boil off subsystems. Such technologies offer promise of increasing the performance of in-space chemical propulsion for energetic space missions. A mass model for pressure-fed, Earth and space-storable, advanced chemical propulsion systems (ACPS) was developed in support of the NASA MSFC In-Space Propulsion Program. Data from flight systems and studies defined baseline system architectures and subsystems and analyses were formulated for parametric scaling relationships for all ACPS subsystem. The paper will first provide summary descriptions of the approaches used for the systems and the subsystems and then present selected analyses to illustrate use of the model for missions with characteristics of current interest.

  14. In-Space Chemical Propulsion System Model

    NASA Technical Reports Server (NTRS)

    Byers, David C.; Woodcock, Gordon; Benfield, M. P. J.

    2004-01-01

    Multiple, new technologies for chemical systems are becoming available and include high temperature rockets, very light propellant tanks and structures, new bipropellant and monopropellant options, lower mass propellant control components, and zero boil off subsystems. Such technologies offer promise of increasing the performance of in-space chemical propulsion for energetic space missions. A mass model for pressure-fed, Earth and space-storable, advanced chemical propulsion systems (ACPS) was developed in support of the NASA MSFC In-Space Propulsion Program. Data from flight systems and studies defined baseline system architectures and subsystems and analyses were formulated for parametric scaling relationships for all ACPS subsystems. The paper will first provide summary descriptions of the approaches used for the systems and the subsystems and then present selected analyses to illustrate use of the model for missions with characteristics of current interest.

  15. Model based systems engineering for astronomical projects

    NASA Astrophysics Data System (ADS)

    Karban, R.; Andolfato, L.; Bristow, P.; Chiozzi, G.; Esselborn, M.; Schilling, M.; Schmid, C.; Sommer, H.; Zamparelli, M.

    2014-08-01

    Model Based Systems Engineering (MBSE) is an emerging field of systems engineering for which the System Modeling Language (SysML) is a key enabler for descriptive, prescriptive and predictive models. This paper surveys some of the capabilities, expectations and peculiarities of tools-assisted MBSE experienced in real-life astronomical projects. The examples range in depth and scope across a wide spectrum of applications (for example documentation, requirements, analysis, trade studies) and purposes (addressing a particular development need, or accompanying a project throughout many - if not all - its lifecycle phases, fostering reuse and minimizing ambiguity). From the beginnings of the Active Phasing Experiment, through VLT instrumentation, VLTI infrastructure, Telescope Control System for the E-ELT, until Wavefront Control for the E-ELT, we show how stepwise refinements of tools, processes and methods have provided tangible benefits to customary system engineering activities like requirement flow-down, design trade studies, interfaces definition, and validation, by means of a variety of approaches (like Model Checking, Simulation, Model Transformation) and methodologies (like OOSEM, State Analysis)

  16. Structural Identifiability of Dynamic Systems Biology Models

    PubMed Central

    Villaverde, Alejandro F.

    2016-01-01

    A powerful way of gaining insight into biological systems is by creating a nonlinear differential equation model, which usually contains many unknown parameters. Such a model is called structurally identifiable if it is possible to determine the values of its parameters from measurements of the model outputs. Structural identifiability is a prerequisite for parameter estimation, and should be assessed before exploiting a model. However, this analysis is seldom performed due to the high computational cost involved in the necessary symbolic calculations, which quickly becomes prohibitive as the problem size increases. In this paper we show how to analyse the structural identifiability of a very general class of nonlinear models by extending methods originally developed for studying observability. We present results about models whose identifiability had not been previously determined, report unidentifiabilities that had not been found before, and show how to modify those unidentifiable models to make them identifiable. This method helps prevent problems caused by lack of identifiability analysis, which can compromise the success of tasks such as experiment design, parameter estimation, and model-based optimization. The procedure is called STRIKE-GOLDD (STRuctural Identifiability taKen as Extended-Generalized Observability with Lie Derivatives and Decomposition), and it is implemented in a MATLAB toolbox which is available as open source software. The broad applicability of this approach facilitates the analysis of the increasingly complex models used in systems biology and other areas. PMID:27792726

  17. Oxygen production System Models for Lunar ISRU

    NASA Technical Reports Server (NTRS)

    Santiago-Maldonado, Edgardo

    2007-01-01

    In-Situ Resource Utilization (ISRU) seeks to make human space exploration feasible; by using available resources from a planet or the moon to produce consumables, parts, and structures that otherwise would be brought from Earth. Producing these in situ reduces the mass of such that must be launched and doing so allows more payload mass' for each mission. The production of oxygen from lunar regolith, for life support and propellant, is one of the tasks being studied under ISRU. NASA is currently funding three processes that have shown technical merit for the production of oxygen from regolith: Molten Salt Electrolysis, Hydrogen Reduction of Ilmenite, and Carbothermal Reduction. The ISRU program is currently developing system models of, the , abovementioned processes to: (1) help NASA in the evaluation process to select the most cost-effective and efficient process for further prototype development, (2) identify key parameters, (3) optimize the oxygen production process, (4) provide estimates on energy and power requirements, mass and volume.of the system, oxygen production rate, mass of regolith required, mass of consumables, and other important parameters, and (5) integrate into the overall end-to-end ISRU system model, which could be integrated with mission architecture models. The oxygen production system model is divided into modules that represent unit operations (e.g., reactor, water electrolyzer, heat exchanger). Each module is modeled theoretically using Excel and Visual Basic for Applications (VBA), and will be validated using experimental data from on-going laboratory work. This modularity (plug-n-play) feature of each unit operation allows the use of the same model on different oxygen production systems simulations resulting in comparable results. In this presentation, preliminary results for mass, power, volume will be presented along with brief description of the oxygen production system model.

  18. Global Analysis, Interpretation and Modelling: An Earth Systems Modelling Program

    NASA Technical Reports Server (NTRS)

    Moore, Berrien, III; Sahagian, Dork

    1997-01-01

    The Goal of the GAIM is: To advance the study of the coupled dynamics of the Earth system using as tools both data and models; to develop a strategy for the rapid development, evaluation, and application of comprehensive prognostic models of the Global Biogeochemical Subsystem which could eventually be linked with models of the Physical-Climate Subsystem; to propose, promote, and facilitate experiments with existing models or by linking subcomponent models, especially those associated with IGBP Core Projects and with WCRP efforts. Such experiments would be focused upon resolving interface issues and questions associated with developing an understanding of the prognostic behavior of key processes; to clarify key scientific issues facing the development of Global Biogeochemical Models and the coupling of these models to General Circulation Models; to assist the Intergovernmental Panel on Climate Change (IPCC) process by conducting timely studies that focus upon elucidating important unresolved scientific issues associated with the changing biogeochemical cycles of the planet and upon the role of the biosphere in the physical-climate subsystem, particularly its role in the global hydrological cycle; and to advise the SC-IGBP on progress in developing comprehensive Global Biogeochemical Models and to maintain scientific liaison with the WCRP Steering Group on Global Climate Modelling.

  19. Qualitative models for space system engineering

    NASA Technical Reports Server (NTRS)

    Forbus, Kenneth D.

    1990-01-01

    The objectives of this project were: (1) to investigate the implications of qualitative modeling techniques for problems arising in the monitoring, diagnosis, and design of Space Station subsystems and procedures; (2) to identify the issues involved in using qualitative models to enhance and automate engineering functions. These issues include representing operational criteria, fault models, alternate ontologies, and modeling continuous signals at a functional level of description; and (3) to develop a prototype collection of qualitative models for fluid and thermal systems commonly found in Space Station subsystems. Potential applications of qualitative modeling to space-systems engineering, including the notion of intelligent computer-aided engineering are summarized. Emphasis is given to determining which systems of the proposed Space Station provide the most leverage for study, given the current state of the art. Progress on using qualitative models, including development of the molecular collection ontology for reasoning about fluids, the interaction of qualitative and quantitative knowledge in analyzing thermodynamic cycles, and an experiment on building a natural language interface to qualitative reasoning is reported. Finally, some recommendations are made for future research.

  20. Interval modeling of dynamics for multibody systems

    NASA Astrophysics Data System (ADS)

    Auer, Ekaterina

    2007-02-01

    Modeling of multibody systems is an important though demanding field of application for interval arithmetic. Interval modeling of dynamics is particularly challenging, not least because of the differential equations which have to be solved in the process. Most modeling tools transform these equations into a (non-autonomous) initial value problem, interval algorithms for solving of which are known. The challenge then consists in finding interfaces between these algorithms and the modeling tools. This includes choosing between "symbolic" and "numerical" modeling environments, transforming the usually non-autonomous resulting system into an autonomous one, ensuring conformity of the new interval version to the old numerical, etc. In this paper, we focus on modeling multibody systems' dynamics with the interval extension of the "numerical" environment MOBILE, discuss the techniques which make the uniform treatment of interval and non-interval modeling easier, comment on the wrapping effect, and give reasons for our choice of MOBILE by comparing the results achieved with its help with those obtained by analogous symbolic tools.

  1. Wind Technology Modeling Within the System Advisor Model (SAM) (Poster)

    SciTech Connect

    Blair, N.; Dobos, A.; Ferguson, T.; Freeman, J.; Gilman, P.; Whitmore, J.

    2014-05-01

    This poster provides detail for implementation and the underlying methodology for modeling wind power generation performance in the National Renewable Energy Laboratory's (NREL's) System Advisor Model (SAM). SAM's wind power model allows users to assess projects involving one or more large or small wind turbines with any of the detailed options for residential, commercial, or utility financing. The model requires information about the wind resource, wind turbine specifications, wind farm layout (if applicable), and costs, and provides analysis to compare the absolute or relative impact of these inputs. SAM is a system performance and economic model designed to facilitate analysis and decision-making for project developers, financers, policymakers, and energy researchers. The user pairs a generation technology with a financing option (residential, commercial, or utility) to calculate the cost of energy over the multi-year project period. Specifically, SAM calculates the value of projects which buy and sell power at retail rates for residential and commercial systems, and also for larger-scale projects which operate through a power purchase agreement (PPA) with a utility. The financial model captures complex financing and rate structures, taxes, and incentives.

  2. The Alpha Project, a model system for systems biology research

    PubMed Central

    Yu, Richard C.; Resnekov, Orna; Abola, A. Pia; Andrews, Steve S.; Benjamin, Kirsten R.; Bruck, Jehoshua; Burbulis, Ian; Colman-Lerner, Alejandro; Endy, Drew; Gordon, Andrew; Holl, Mark; Lok, Larry; Pesce, Gustavo; Serra, Eduard; Smith, Richard D.; Thomson, Ty M.; Tsong, Annie E.; Brent, Roger

    2009-01-01

    One goal of systems biology is to understand how genome-encoded parts interact to produce quantitative phenotypes. The Alpha Project is a medium-scale, interdisciplinary systems biology effort that aims to achieve this goal by understanding fundamental quantitative behaviors of a prototypic signal transduction pathway, the yeast pheromone response system from Saccharomyces cerevisiae. The Alpha Project distinguishes itself from many other systems biology projects by studying a tightly-bounded and well-characterized system that is easily modified by genetic means, and by focusing on deep understanding of a discrete number of important and accessible quantitative behaviors. During the project, we have developed tools to measure the appropriate data and develop models at appropriate levels of detail for studying a number of these quantitative behaviors. We also have developed transportable experimental tools and conceptual frameworks for understanding other signaling systems. In particular, we have begun to interpret system behaviors and their underlying molecular mechanisms through the lens of information transmission, a principal function of signaling systems. The Alpha Project demonstrates that interdisciplinary studies that identify key quantitative behaviors and measure important quantities, in the context of well-articulated abstractions of system function and appropriate analytical frameworks, can lead to deeper biological understanding. Our experience may provide a productive template for system biology investigations of other cellular systems. PMID:19045818

  3. Learning Preference Models in Recommender Systems

    NASA Astrophysics Data System (ADS)

    Gemmis, Marco De; Iaquinta, Leo; Lops, Pasquale; Musto, Cataldo; Narducci, Fedelucio; Semeraro, Giovanni

    As proved by the continuous growth of the number of web sites which embody recommender systems as a way of personalizing the experience of users with their content, recommender systems represent one of the most popular applications of principles and techniques coming from Information Filtering (IF). As IF techniques usually perform a progressive removal of nonrelevant content according to the information stored in a user profile, recommendation algorithms process information about user interests - acquired in an explicit (e.g., letting users express their opinion about items) or implicit (e.g., studying some behavioral features) way - and exploit these data to generate a list of recommended items. Although each type of filtering method has its own weaknesses and strengths, preference handling is one of the core issues in the design of every recommender system: since these systems aim to guide users in a personalized way to interesting or useful objects in a large space of possible options, it is important for them to accurately capture and model user preferences. The goal of this chapter is to provide a general overview of the approaches to learning preference models in the context of recommender systems. In the first part, we introduce general concepts and terminology of recommender systems, giving a brief analysis of advantages and drawbacks for each filtering approach. Then we will deal with the issue of learning preference models, show the most popular techniques for profile learning and preference elicitation, and analyze methods for feedback gathering in recommender systems.

  4. System model development for nuclear thermal propulsion

    NASA Technical Reports Server (NTRS)

    Walton, James T.; Hannan, Nelson A.; Perkins, Ken R.; Buksa, John H.; Worley, Brian A.; Dobranich, Dean

    1992-01-01

    A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. This is crucial for mission analysis and for control subsystem testing as well as for the modeling of various failure modes. Performance must be accurately predicted during steady-state and transient operation, including startup, shutdown, and post operation cooling. The development and application of verified and validated system models has the potential to reduce the design, testing, and cost and time required for the technology to reach flight-ready status. Since Oct. 1991, the U.S. Department of Energy (DOE), Department of Defense (DOD), and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. The first level will provide rapid, parameterized calculations of overall system performance. Succeeding computer programs will provide analysis of each component in sufficient detail to guide the design teams and experimental efforts. The computer programs will allow simulation of the entire system to allow prediction of the integrated performance. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review.

  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. Model authoring system for fail safe analysis

    NASA Technical Reports Server (NTRS)

    Sikora, Scott E.

    1990-01-01

    The Model Authoring System is a prototype software application for generating fault tree analyses and failure mode and effects analyses for circuit designs. Utilizing established artificial intelligence and expert system techniques, the circuits are modeled as a frame-based knowledge base in an expert system shell, which allows the use of object oriented programming and an inference engine. The behavior of the circuit is then captured through IF-THEN rules, which then are searched to generate either a graphical fault tree analysis or failure modes and effects analysis. Sophisticated authoring techniques allow the circuit to be easily modeled, permit its behavior to be quickly defined, and provide abstraction features to deal with complexity.

  7. The Red Sea Modeling and Forecasting System

    NASA Astrophysics Data System (ADS)

    Hoteit, Ibrahim; Gopalakrishnan, Ganesh; Latif, Hatem; Toye, Habib; Zhan, Peng; Kartadikaria, Aditya R.; Viswanadhapalli, Yesubabu; Yao, Fengchao; Triantafyllou, George; Langodan, Sabique; Cavaleri, Luigi; Guo, Daquan; Johns, Burt

    2015-04-01

    Despite its importance for a variety of socio-economical and political reasons and the presence of extensive coral reef gardens along its shores, the Red Sea remains one of the most under-studied large marine physical and biological systems in the global ocean. This contribution will present our efforts to build advanced modeling and forecasting capabilities for the Red Sea, which is part of the newly established Saudi ARAMCO Marine Environmental Research Center at KAUST (SAMERCK). Our Red Sea modeling system compromises both regional and nested costal MIT general circulation models (MITgcm) with resolutions varying between 8 km and 250 m to simulate the general circulation and mesoscale dynamics at various spatial scales, a 10-km resolution Weather Research Forecasting (WRF) model to simulate the atmospheric conditions, a 4-km resolution European Regional Seas Ecosystem Model (ERSEM) to simulate the Red Sea ecosystem, and a 1-km resolution WAVEWATCH-III model to simulate the wind driven surface waves conditions. We have also implemented an oil spill model, and a probabilistic dispersion and larval connectivity modeling system (CMS) based on a stochastic Lagrangian framework and incorporating biological attributes. We are using the models outputs together with available observational data to study all aspects of the Red Sea circulations. Advanced monitoring capabilities are being deployed in the Red Sea as part of the SAMERCK, comprising multiple gliders equipped with hydrographical and biological sensors, high frequency (HF) surface current/wave mapping, buoys/ moorings, etc, complementing the available satellite ocean and atmospheric observations and Automatic Weather Stations (AWS). The Red Sea models have also been equipped with advanced data assimilation capabilities. Fully parallel ensemble-based Kalman filtering (EnKF) algorithms have been implemented with the MITgcm and ERSEM for assimilating all available multivariate satellite and in-situ data sets. We

  8. C. elegans: a model system for systems neuroscience

    PubMed Central

    Sengupta, Piali; Samuel, Aravinthan D.T.

    2009-01-01

    Summary The nematode C. elegans is an excellent model organism for a systems-level understanding of neural circuits and behavior. Advances in the quantitative analyses of behavior and neuronal activity, and the development of new technologies to precisely control and monitor the workings of interconnected circuits, now allow investigations into the molecular, cellular and systems-level strategies that transform sensory inputs into precise behavioral outcomes. PMID:19896359

  9. Wind turbine control system modeling capabilities

    SciTech Connect

    Pierce, K.; Fingersh, L.J.

    1998-04-01

    At the National Renewable Energy Laboratory`s (NREL`s) National Wind Technology Center the authors are continuing to make progress in their ability to model complete wind turbine systems. An ADAMS{reg_sign} model of the NREL variable speed test bed turbine was developed to determine whether wind turbine control systems could be simulated and to investigate other control strategies for this turbine. Model simulations are compared with data from the operating turbine using the current mode of operation. In general, the simulations show good agreement with test data. Having established confidence in their ability to model the physical machine, the authors evaluated two other control methods. The methods studied are a generalized predictive control method and a bias estimation method. Simulation results using these methods are compared to simulation results of the current mode of operation of the turbine.

  10. Functional Risk Modeling for Lunar Surface Systems

    NASA Technical Reports Server (NTRS)

    Thomson, Fraser; Mathias, Donovan; Go, Susie; Nejad, Hamed

    2010-01-01

    We introduce an approach to risk modeling that we call functional modeling , which we have developed to estimate the capabilities of a lunar base. The functional model tracks the availability of functions provided by systems, in addition to the operational state of those systems constituent strings. By tracking functions, we are able to identify cases where identical functions are provided by elements (rovers, habitats, etc.) that are connected together on the lunar surface. We credit functional diversity in those cases, and in doing so compute more realistic estimates of operational mode availabilities. The functional modeling approach yields more realistic estimates of the availability of the various operational modes provided to astronauts by the ensemble of surface elements included in a lunar base architecture. By tracking functional availability the effects of diverse backup, which often exists when two or more independent elements are connected together, is properly accounted for.

  11. Spatial Database Modeling for Indoor Navigation Systems

    NASA Astrophysics Data System (ADS)

    Gotlib, Dariusz; Gnat, Miłosz

    2013-12-01

    For many years, cartographers are involved in designing GIS and navigation systems. Most GIS applications use the outdoor data. Increasingly, similar applications are used inside buildings. Therefore it is important to find the proper model of indoor spatial database. The development of indoor navigation systems should utilize advanced teleinformation, geoinformatics, geodetic and cartographical knowledge. The authors present the fundamental requirements for the indoor data model for navigation purposes. Presenting some of the solutions adopted in the world they emphasize that navigation applications require specific data to present the navigation routes in the right way. There is presented original solution for indoor data model created by authors on the basis of BISDM model. Its purpose is to expand the opportunities for use in indoor navigation.

  12. Performance modeling for large database systems

    NASA Astrophysics Data System (ADS)

    Schaar, Stephen; Hum, Frank; Romano, Joe

    1997-02-01

    One of the unique approaches Science Applications International Corporation took to meet performance requirements was to start the modeling effort during the proposal phase of the Interstate Identification Index/Federal Bureau of Investigations (III/FBI) project. The III/FBI Performance Model uses analytical modeling techniques to represent the III/FBI system. Inputs to the model include workloads for each transaction type, record size for each record type, number of records for each file, hardware envelope characteristics, engineering margins and estimates for software instructions, memory, and I/O for each transaction type. The model uses queuing theory to calculate the average transaction queue length. The model calculates a response time and the resources needed for each transaction type. Outputs of the model include the total resources needed for the system, a hardware configuration, and projected inherent and operational availability. The III/FBI Performance Model is used to evaluate what-if scenarios and allows a rapid response to engineering change proposals and technical enhancements.

  13. Fujisaki Model Based Intonation Modeling for Korean TTS System

    NASA Astrophysics Data System (ADS)

    Kim, Byeongchang; Lee, Jinsik; Lee, Gary Geunbae

    One of the enduring problems in developing high-quality TTS (text-to-speech) system is pitch contour generation. Considering language specific knowledge, an adjusted Fujisaki model for Korean TTS system is introduced along with refined machine learning features. The results of quantitative and qualitative evaluations show the validity of our system: the accuracy of the phrase command prediction is 0.8928; the correlations of the predicted amplitudes of a phrase command and an accent command are 0.6644 and 0.6002, respectively; our method achieved the level of "fair" naturalness (3.6) in a MOS scale for generated F0 curves.

  14. The integrated Regional Earth System Model

    NASA Astrophysics Data System (ADS)

    Kraucunas, I.; Clarke, L.; Dirks, J.; Hejazi, M. I.; Hibbard, K. A.; Huang, M.; Janetos, A. C.; Kintner-Meyer, M.; Kleese van Dam, K.; Leung, L.; Moss, R. H.; Rice, J.; Scott, M. J.; Thomson, A. M.; West, T. O.; Whitney, P.; Yang, Z.

    2012-12-01

    The integrated Regional Earth System Model (iRESM) is a unique modeling framework being developed at Pacific Northwest National Laboratory (PNNL) to simulate the interactions among natural and human systems at scales relevant to regional decision making. The framework unites high-resolution models of regional climate, hydrology, agriculture, socioeconomics, and energy systems using a flexible software architecture. The framework is portable and can be customized to inform a variety of complex questions and decisions, including (but not limited to) planning, implementation, and evaluation of mitigation and adaptation options across a range of sectors. iRESM also incorporates extensive stakeholder interactions and analysis to inform model development, coupling strategies, and characterization of uncertainties. Ongoing numerical experiments are yielding new insights into the interactions among human and natural systems on regional scales, with an initial focus on the energy-land-water nexus and the penetration of renewable energy technologies in the upper U.S. Midwest. The iRESM framework also is being extended and applied to the U.S. Gulf Coast, with a particular emphasis on how changes in extreme events will affect both coastal in inland energy infrastructure in the region. This talk will focus on iRESM's development and capabilities, initial results from numerical experiments, and the challenges and opportunities associated with integrated regional modeling.

  15. Trends in modeling Biomedical Complex Systems

    PubMed Central

    Milanesi, Luciano; Romano, Paolo; Castellani, Gastone; Remondini, Daniel; Liò, Petro

    2009-01-01

    In this paper we provide an introduction to the techniques for multi-scale complex biological systems, from the single bio-molecule to the cell, combining theoretical modeling, experiments, informatics tools and technologies suitable for biological and biomedical research, which are becoming increasingly multidisciplinary, multidimensional and information-driven. The most important concepts on mathematical modeling methodologies and statistical inference, bioinformatics and standards tools to investigate complex biomedical systems are discussed and the prominent literature useful to both the practitioner and the theoretician are presented. PMID:19828068

  16. Reliability models for dataflow computer systems

    NASA Technical Reports Server (NTRS)

    Kavi, K. M.; Buckles, B. P.

    1985-01-01

    The demands for concurrent operation within a computer system and the representation of parallelism in programming languages have yielded a new form of program representation known as data flow (DENN 74, DENN 75, TREL 82a). A new model based on data flow principles for parallel computations and parallel computer systems is presented. Necessary conditions for liveness and deadlock freeness in data flow graphs are derived. The data flow graph is used as a model to represent asynchronous concurrent computer architectures including data flow computers.

  17. New models for circadian systems in microorganisms.

    PubMed

    Lakin-Thomas, Patricia L

    2006-06-01

    Microorganisms provide important model systems for studying circadian rhythms, and they are overturning established ideas about the molecular mechanisms of rhythmicity. The transcription/translation feedback model that has been accepted as the basis of circadian clock mechanisms in eukaryotes does not account for old data from the alga Acetabularia demonstrating that transcription is not required for rhythmicity. Moreover, new results showing in vitro rhythmicity of KaiC protein phosphorylation in the cyanobacterium Synechococcus, and rhythmicity in strains of the fungus Neurospora carrying clock gene null mutations, require new ways of looking at circadian systems.

  18. Performance modeling of nonconcentrating solar detoxification systems

    SciTech Connect

    March, M.; Martin, A.; Saltiel, C.

    1995-03-01

    A detailed simulation model is developed for predicting the performance of solar detoxification systems. Concentration profiles are determined via a method of lines approach during sunlight hours for acquired and synthetic (simulating clear and cloudy days) ultraviolet radiation intensity data. Verification of the model is performed with comparison against indoor laboratory and outdoor field test results. Simulations are performed over a range of design parameters to examine system sensitivity. Discussions are focused on the determination of optimal sizing and operating conditions. 17 refs., 8 figs.

  19. Integrated Modeling of Complex Optomechanical Systems

    NASA Astrophysics Data System (ADS)

    Andersen, Torben; Enmark, Anita

    2011-09-01

    Mathematical modeling and performance simulation are playing an increasing role in large, high-technology projects. There are two reasons; first, projects are now larger than they were before, and the high cost calls for detailed performance prediction before construction. Second, in particular for space-related designs, it is often difficult to test systems under realistic conditions beforehand, and mathematical modeling is then needed to verify in advance that a system will work as planned. Computers have become much more powerful, permitting calculations that were not possible before. At the same time mathematical tools have been further developed and found acceptance in the community. Particular progress has been made in the fields of structural mechanics, optics and control engineering, where new methods have gained importance over the last few decades. Also, methods for combining optical, structural and control system models into global models have found widespread use. Such combined models are usually called integrated models and were the subject of this symposium. The objective was to bring together people working in the fields of groundbased optical telescopes, ground-based radio telescopes, and space telescopes. We succeeded in doing so and had 39 interesting presentations and many fruitful discussions during coffee and lunch breaks and social arrangements. We are grateful that so many top ranked specialists found their way to Kiruna and we believe that these proceedings will prove valuable during much future work.

  20. Modeling leaks from liquid hydrogen storage systems.

    SciTech Connect

    Winters, William Stanley, Jr.

    2009-01-01

    This report documents a series of models for describing intended and unintended discharges from liquid hydrogen storage systems. Typically these systems store hydrogen in the saturated state at approximately five to ten atmospheres. Some of models discussed here are equilibrium-based models that make use of the NIST thermodynamic models to specify the states of multiphase hydrogen and air-hydrogen mixtures. Two types of discharges are considered: slow leaks where hydrogen enters the ambient at atmospheric pressure and fast leaks where the hydrogen flow is usually choked and expands into the ambient through an underexpanded jet. In order to avoid the complexities of supersonic flow, a single Mach disk model is proposed for fast leaks that are choked. The velocity and state of hydrogen downstream of the Mach disk leads to a more tractable subsonic boundary condition. However, the hydrogen temperature exiting all leaks (fast or slow, from saturated liquid or saturated vapor) is approximately 20.4 K. At these temperatures, any entrained air would likely condense or even freeze leading to an air-hydrogen mixture that cannot be characterized by the REFPROP subroutines. For this reason a plug flow entrainment model is proposed to treat a short zone of initial entrainment and heating. The model predicts the quantity of entrained air required to bring the air-hydrogen mixture to a temperature of approximately 65 K at one atmosphere. At this temperature the mixture can be treated as a mixture of ideal gases and is much more amenable to modeling with Gaussian entrainment models and CFD codes. A Gaussian entrainment model is formulated to predict the trajectory and properties of a cold hydrogen jet leaking into ambient air. The model shows that similarity between two jets depends on the densimetric Froude number, density ratio and initial hydrogen concentration.

  1. Code System to Model Aqueous Geochemical Equilibria.

    2001-08-23

    Version: 00 MINTEQ is a geochemical program to model aqueous solutions and the interactions of aqueous solutions with hypothesized assemblages of solid phases. It was developed for the Environmental Protection Agency to perform the calculations necessary to simulate the contact of waste solutions with heterogeneous sediments or the interaction of ground water with solidified wastes. MINTEQ can calculate ion speciation/solubility, adsorption, oxidation-reduction, gas phase equilibria, and precipitation/dissolution ofsolid phases. MINTEQ can accept a finite massmore » for any solid considered for dissolution and will dissolve the specified solid phase only until its initial mass is exhausted. This ability enables MINTEQ to model flow-through systems. In these systems the masses of solid phases that precipitate at earlier pore volumes can be dissolved at later pore volumes according to thermodynamic constraints imposed by the solution composition and solid phases present. The ability to model these systems permits evaluation of the geochemistry of dissolved traced metals, such as low-level waste in shallow land burial sites. MINTEQ was designed to solve geochemical equilibria for systems composed of one kilogram of water, various amounts of material dissolved in solution, and any solid materials that are present. Systems modeled using MINTEQ can exchange energy and material (open systems) or just energy (closed systems) with the surrounding environment. Each system is composed of a number of phases. Every phase is a region with distinct composition and physically definable boundaries. All of the material in the aqueous solution forms one phase. The gas phase is composed of any gaseous material present, and each compositionally and structurally distinct solid forms a separate phase.« less

  2. Global dynamic modeling of a transmission system

    NASA Technical Reports Server (NTRS)

    Choy, F. K.; Qian, W.

    1993-01-01

    The work performed on global dynamic simulation and noise correlation of gear transmission systems at the University of Akron is outlined. The objective is to develop a comprehensive procedure to simulate the dynamics of the gear transmission system coupled with the effects of gear box vibrations. The developed numerical model is benchmarked with results from experimental tests at NASA Lewis Research Center. The modal synthesis approach is used to develop the global transient vibration analysis procedure used in the model. Modal dynamic characteristics of the rotor-gear-bearing system are calculated by the matrix transfer method while those of the gear box are evaluated by the finite element method (NASTRAN). A three-dimensional, axial-lateral coupled bearing model is used to couple the rotor vibrations with the gear box motion. The vibrations between the individual rotor systems are coupled through the nonlinear gear mesh interactions. The global equations of motion are solved in modal coordinates and the transient vibration of the system is evaluated by a variable time-stepping integration scheme. The relationship between housing vibration and resulting noise of the gear transmission system is generated by linear transfer functions using experimental data. A nonlinear relationship of the noise components to the fundamental mesh frequency is developed using the hypercoherence function. The numerically simulated vibrations and predicted noise of the gear transmission system are compared with the experimental results from the gear noise test rig at NASA Lewis Research Center. Results of the comparison indicate that the global dynamic model developed can accurately simulate the dynamics of a gear transmission system.

  3. Combustion modeling in advanced gas turbine systems

    SciTech Connect

    Smoot, L.D.; Hedman, P.O.; Fletcher, T.H.

    1995-10-01

    The goal of the U.S. Department of Energy`s Advanced Turbine Systems (ATS) program is to help develop and commercialize ultra-high efficiency, environmentally superior, and cost competitive gas turbine systems for base-load applications in the utility, independent power producer, and industrial markets. Combustion modeling, including emission characteristics, has been identified as a needed, high-priority technology by key professionals in the gas turbine industry.

  4. Global dynamic modeling of a transmission system

    NASA Astrophysics Data System (ADS)

    Choy, F. K.; Qian, W.

    1993-04-01

    The work performed on global dynamic simulation and noise correlation of gear transmission systems at the University of Akron is outlined. The objective is to develop a comprehensive procedure to simulate the dynamics of the gear transmission system coupled with the effects of gear box vibrations. The developed numerical model is benchmarked with results from experimental tests at NASA Lewis Research Center. The modal synthesis approach is used to develop the global transient vibration analysis procedure used in the model. Modal dynamic characteristics of the rotor-gear-bearing system are calculated by the matrix transfer method while those of the gear box are evaluated by the finite element method (NASTRAN). A three-dimensional, axial-lateral coupled bearing model is used to couple the rotor vibrations with the gear box motion. The vibrations between the individual rotor systems are coupled through the nonlinear gear mesh interactions. The global equations of motion are solved in modal coordinates and the transient vibration of the system is evaluated by a variable time-stepping integration scheme. The relationship between housing vibration and resulting noise of the gear transmission system is generated by linear transfer functions using experimental data. A nonlinear relationship of the noise components to the fundamental mesh frequency is developed using the hypercoherence function. The numerically simulated vibrations and predicted noise of the gear transmission system are compared with the experimental results from the gear noise test rig at NASA Lewis Research Center. Results of the comparison indicate that the global dynamic model developed can accurately simulate the dynamics of a gear transmission system.

  5. Modeling of DC spacecraft power systems

    NASA Technical Reports Server (NTRS)

    Berry, F. C.

    1995-01-01

    Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.

  6. Modeling of DC spacecraft power systems

    NASA Astrophysics Data System (ADS)

    Berry, F. C.

    1995-07-01

    Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.

  7. Cognitive engineering models in space systems

    NASA Technical Reports Server (NTRS)

    Mitchell, Christine M.

    1993-01-01

    NASA space systems, including mission operations on the ground and in space, are complex, dynamic, predominantly automated systems in which the human operator is a supervisory controller. Models of cognitive functions in complex systems are needed to describe human performance and form the theoretical basis of operator workstation design, including displays, controls, and decision aids. Currently, there several candidate modeling methodologies. They include the Rasmussen abstraction/aggregation hierarchy and decision ladder, the goal-means network, the problem behavior graph, and the operator function model. The research conducted under the sponsorship of this grant focuses on the extension of the theoretical structure of the operator function model and its application to NASA Johnson mission operations and space station applications. The initial portion of this research consists of two parts. The first is a series of technical exchanges between NASA Johnson and Georgia Tech researchers. The purpose is to identify candidate applications for the current operator function model; prospects include mission operations and the Data Management System Testbed. The second portion will address extensions of the operator function model to tailor it to the specific needs of Johnson applications. At this point, we have accomplished two things. During a series of conversations with JSC researchers, we have defined the technical goal of the research supported by this grant to be the structural definition of the operator function model and its computer implementation, OFMspert. Both the OFM and OFMspert have matured to the point that they require infrastructure to facilitate use by researchers not involved in the evolution of the tools. The second accomplishment this year was the identification of the Payload Deployment and Retrieval System (PDRS) as a candidate system for the case study. In conjunction with government and contractor personnel in the Human-Computer Interaction Lab

  8. The Launch Systems Operations Cost Model

    NASA Technical Reports Server (NTRS)

    Prince, Frank A.; Hamaker, Joseph W. (Technical Monitor)

    2001-01-01

    One of NASA's primary missions is to reduce the cost of access to space while simultaneously increasing safety. A key component, and one of the least understood, is the recurring operations and support cost for reusable launch systems. In order to predict these costs, NASA, under the leadership of the Independent Program Assessment Office (IPAO), has commissioned the development of a Launch Systems Operations Cost Model (LSOCM). LSOCM is a tool to predict the operations & support (O&S) cost of new and modified reusable (and partially reusable) launch systems. The requirements are to predict the non-recurring cost for the ground infrastructure and the recurring cost of maintaining that infrastructure, performing vehicle logistics, and performing the O&S actions to return the vehicle to flight. In addition, the model must estimate the time required to cycle the vehicle through all of the ground processing activities. The current version of LSOCM is an amalgamation of existing tools, leveraging our understanding of shuttle operations cost with a means of predicting how the maintenance burden will change as the vehicle becomes more aircraft like. The use of the Conceptual Operations Manpower Estimating Tool/Operations Cost Model (COMET/OCM) provides a solid point of departure based on shuttle and expendable launch vehicle (ELV) experience. The incorporation of the Reliability and Maintainability Analysis Tool (RMAT) as expressed by a set of response surface model equations gives a method for estimating how changing launch system characteristics affects cost and cycle time as compared to today's shuttle system. Plans are being made to improve the model. The development team will be spending the next few months devising a structured methodology that will enable verified and validated algorithms to give accurate cost estimates. To assist in this endeavor the LSOCM team is part of an Agency wide effort to combine resources with other cost and operations professionals to

  9. Adaptive cyber-attack modeling system

    NASA Astrophysics Data System (ADS)

    Gonsalves, Paul G.; Dougherty, Edward T.

    2006-05-01

    The pervasiveness of software and networked information systems is evident across a broad spectrum of business and government sectors. Such reliance provides an ample opportunity not only for the nefarious exploits of lone wolf computer hackers, but for more systematic software attacks from organized entities. Much effort and focus has been placed on preventing and ameliorating network and OS attacks, a concomitant emphasis is required to address protection of mission critical software. Typical software protection technique and methodology evaluation and verification and validation (V&V) involves the use of a team of subject matter experts (SMEs) to mimic potential attackers or hackers. This manpower intensive, time-consuming, and potentially cost-prohibitive approach is not amenable to performing the necessary multiple non-subjective analyses required to support quantifying software protection levels. To facilitate the evaluation and V&V of software protection solutions, we have designed and developed a prototype adaptive cyber attack modeling system. Our approach integrates an off-line mechanism for rapid construction of Bayesian belief network (BN) attack models with an on-line model instantiation, adaptation and knowledge acquisition scheme. Off-line model construction is supported via a knowledge elicitation approach for identifying key domain requirements and a process for translating these requirements into a library of BN-based cyber-attack models. On-line attack modeling and knowledge acquisition is supported via BN evidence propagation and model parameter learning.

  10. Modelling water uptake efficiency of root systems

    NASA Astrophysics Data System (ADS)

    Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

    2016-04-01

    Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

  11. A Model-Based Expert System For Digital Systems Design

    NASA Astrophysics Data System (ADS)

    Wu, J. G.; Ho, W. P. C.; Hu, Y. H.; Yun, D. Y. Y.; Parng, T. M.

    1987-05-01

    In this paper, we present a model-based expert system for automatic digital systems design. The goal of digital systems design is to generate a workable and efficient design from high level specifications. The formalization of the design process is a necessity for building an efficient automatic CAD system. Our approach combines model-based, heuristic best-first search, and meta-planning techniques from AI to facilitate the design process. The design process is decomposed into three subprocesses. First, the high-level behavioral specifications are translated into sequences of primitive behavioral operations. Next, primitive operations are grouped to form intermediate-level behavioral functions. Finally, structural function modules are selected to implement these functions. Using model-based reasoning on the primitive behavioral operations level extends the solution space considered in design and provides more opportunity for minimization. Heuristic best-first search and meta-planning tech-niques control the decision-making in the latter two subprocesses to optimize the final design. They also facilitate system maintenance by separating design strategy from design knowledge.

  12. Modeling Parallel System Workloads with Temporal Locality

    NASA Astrophysics Data System (ADS)

    Minh, Tran Ngoc; Wolters, Lex

    In parallel systems, similar jobs tend to arrive within bursty periods. This fact leads to the existence of the locality phenomenon, a persistent similarity between nearby jobs, in real parallel computer workloads. This important phenomenon deserves to be taken into account and used as a characteristic of any workload model. Regrettably, this property has received little if any attention of researchers and synthetic workloads used for performance evaluation to date often do not have locality. With respect to this research trend, Feitelson has suggested a general repetition approach to model locality in synthetic workloads [6]. Using this approach, Li et al. recently introduced a new method for modeling temporal locality in workload attributes such as run time and memory [14]. However, with the assumption that each job in the synthetic workload requires a single processor, the parallelism has not been taken into account in their study. In this paper, we propose a new model for parallel computer workloads based on their result. In our research, we firstly improve their model to control locality of a run time process better and then model the parallelism. The key idea for modeling the parallelism is to control the cross-correlation between the run time and the number of processors. Experimental results show that not only the cross-correlation is controlled well by our model, but also the marginal distribution can be fitted nicely. Furthermore, the locality feature is also obtained in our model.

  13. Combustion modeling in advanced gas turbine systems

    SciTech Connect

    Smoot, L.D.; Hedman, P.O.; Fletcher, T.H.; Brewster, B.S.; Kramer, S.K.

    1995-12-31

    Goal of DOE`s Advanced Turbine Systems program is to develop and commercialize ultra-high efficiency, environmentally superior, cost competitive gas turbine systems for base-load applications in utility, independent power producer, and industrial markets. Primary objective of the program here is to develop a comprehensive combustion model for advanced gas turbine combustion systems using natural gas (coal gasification or biomass fuels). The efforts included code evaluation (PCGC-3), coherent anti-Stokes Raman spectroscopy, laser Doppler anemometry, and laser-induced fluorescence.

  14. Data Model Management for Space Information Systems

    NASA Technical Reports Server (NTRS)

    Hughes, J. Steven; Crichton, Daniel J.; Ramirez, Paul; Mattmann, chris

    2006-01-01

    The Reference Architecture for Space Information Management (RASIM) suggests the separation of the data model from software components to promote the development of flexible information management systems. RASIM allows the data model to evolve independently from the software components and results in a robust implementation that remains viable as the domain changes. However, the development and management of data models within RASIM are difficult and time consuming tasks involving the choice of a notation, the capture of the model, its validation for consistency, and the export of the model for implementation. Current limitations to this approach include the lack of ability to capture comprehensive domain knowledge, the loss of significant modeling information during implementation, the lack of model visualization and documentation capabilities, and exports being limited to one or two schema types. The advent of the Semantic Web and its demand for sophisticated data models has addressed this situation by providing a new level of data model management in the form of ontology tools. In this paper we describe the use of a representative ontology tool to capture and manage a data model for a space information system. The resulting ontology is implementation independent. Novel on-line visualization and documentation capabilities are available automatically, and the ability to export to various schemas can be added through tool plug-ins. In addition, the ingestion of data instances into the ontology allows validation of the ontology and results in a domain knowledge base. Semantic browsers are easily configured for the knowledge base. For example the export of the knowledge base to RDF/XML and RDFS/XML and the use of open source metadata browsers provide ready-made user interfaces that support both text- and facet-based search. This paper will present the Planetary Data System (PDS) data model as a use case and describe the import of the data model into an ontology tool

  15. Cognitive Systems Modeling and Analysis of Command and Control Systems

    NASA Technical Reports Server (NTRS)

    Norlander, Arne

    2012-01-01

    Military operations, counter-terrorism operations and emergency response often oblige operators and commanders to operate within distributed organizations and systems for safe and effective mission accomplishment. Tactical commanders and operators frequently encounter violent threats and critical demands on cognitive capacity and reaction time. In the future they will make decisions in situations where operational and system characteristics are highly dynamic and non-linear, i.e. minor events, decisions or actions may have serious and irreversible consequences for the entire mission. Commanders and other decision makers must manage true real time properties at all levels; individual operators, stand-alone technical systems, higher-order integrated human-machine systems and joint operations forces alike. Coping with these conditions in performance assessment, system development and operational testing is a challenge for both practitioners and researchers. This paper reports on research from which the results led to a breakthrough: An integrated approach to information-centered systems analysis to support future command and control systems research development. This approach integrates several areas of research into a coherent framework, Action Control Theory (ACT). It comprises measurement techniques and methodological advances that facilitate a more accurate and deeper understanding of the operational environment, its agents, actors and effectors, generating new and updated models. This in turn generates theoretical advances. Some good examples of successful approaches are found in the research areas of cognitive systems engineering, systems theory, and psychophysiology, and in the fields of dynamic, distributed decision making and naturalistic decision making.

  16. Modeling acclimatization by hybrid systems: condition changes alter biological system behavior models.

    PubMed

    Assar, Rodrigo; Montecino, Martín A; Maass, Alejandro; Sherman, David J

    2014-07-01

    In order to describe the dynamic behavior of a complex biological system, it is useful to combine models integrating processes at different levels and with temporal dependencies. Such combinations are necessary for modeling acclimatization, a phenomenon where changes in environmental conditions can induce drastic changes in the behavior of a biological system. In this article we formalize the use of hybrid systems as a tool to model this kind of biological behavior. A modeling scheme called strong switches is proposed. It allows one to take into account both minor adjustments to the coefficients of a continuous model, and, more interestingly, large-scale changes to the structure of the model. We illustrate the proposed methodology with two applications: acclimatization in wine fermentation kinetics, and acclimatization of osteo-adipo differentiation system linking stimulus signals to bone mass.

  17. Session 6: Dynamic Modeling and Systems Analysis

    NASA Technical Reports Server (NTRS)

    Csank, Jeffrey; Chapman, Jeffryes; May, Ryan

    2013-01-01

    These presentations cover some of the ongoing work in dynamic modeling and dynamic systems analysis. The first presentation discusses dynamic systems analysis and how to integrate dynamic performance information into the systems analysis. The ability to evaluate the dynamic performance of an engine design may allow tradeoffs between the dynamic performance and operability of a design resulting in a more efficient engine design. The second presentation discusses the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a Simulation system with a library containing the basic building blocks that can be used to create dynamic Thermodynamic Systems. Some of the key features include Turbo machinery components, such as turbines, compressors, etc., and basic control system blocks. T-MAT is written in the Matlab-Simulink environment and is open source software. The third presentation focuses on getting additional performance from the engine by allowing the limit regulators only to be active when a limit is danger of being violated. Typical aircraft engine control architecture is based on MINMAX scheme, which is designed to keep engine operating within prescribed mechanical/operational safety limits. Using a conditionally active min-max limit regulator scheme, additional performance can be gained by disabling non-relevant limit regulators

  18. Model systems for single molecule polymer dynamics

    PubMed Central

    Latinwo, Folarin

    2012-01-01

    Double stranded DNA (dsDNA) has long served as a model system for single molecule polymer dynamics. However, dsDNA is a semiflexible polymer, and the structural rigidity of the DNA double helix gives rise to local molecular properties and chain dynamics that differ from flexible chains, including synthetic organic polymers. Recently, we developed single stranded DNA (ssDNA) as a new model system for single molecule studies of flexible polymer chains. In this work, we discuss model polymer systems in the context of “ideal” and “real” chain behavior considering thermal blobs, tension blobs, hydrodynamic drag and force–extension relations. In addition, we present monomer aspect ratio as a key parameter describing chain conformation and dynamics, and we derive dynamical scaling relations in terms of this molecular-level parameter. We show that asymmetric Kuhn segments can suppress monomer–monomer interactions, thereby altering global chain dynamics. Finally, we discuss ssDNA in the context of a new model system for single molecule polymer dynamics. Overall, we anticipate that future single polymer studies of flexible chains will reveal new insight into the dynamic behavior of “real” polymers, which will highlight the importance of molecular individualism and the prevalence of non-linear phenomena. PMID:22956980

  19. Gas Centrifuge Enrichment Plant Safeguards System Modeling

    SciTech Connect

    Elayat, H A; O'Connell, W J; Boyer, B D

    2006-06-05

    The U.S. Department of Energy (DOE) is interested in developing tools and methods for potential U.S. use in designing and evaluating safeguards systems used in enrichment facilities. This research focuses on analyzing the effectiveness of the safeguards in protecting against the range of safeguards concerns for enrichment plants, including diversion of attractive material and unauthorized modes of use. We developed an Extend simulation model for a generic medium-sized centrifuge enrichment plant. We modeled the material flow in normal operation, plant operational upset modes, and selected diversion scenarios, for selected safeguards systems. Simulation modeling is used to analyze both authorized and unauthorized use of a plant and the flow of safeguards information. Simulation tracks the movement of materials and isotopes, identifies the signatures of unauthorized use, tracks the flow and compilation of safeguards data, and evaluates the effectiveness of the safeguards system in detecting misuse signatures. The simulation model developed could be of use to the International Atomic Energy Agency IAEA, enabling the IAEA to observe and draw conclusions that uranium enrichment facilities are being used only within authorized limits for peaceful uses of nuclear energy. It will evaluate improved approaches to nonproliferation concerns, facilitating deployment of enhanced and cost-effective safeguards systems for an important part of the nuclear power fuel cycle.

  20. Cost effectiveness of recycling: A systems model

    SciTech Connect

    Tonjes, David J.; Mallikarjun, Sreekanth

    2013-11-15

    Highlights: • Curbside collection of recyclables reduces overall system costs over a range of conditions. • When avoided costs for recyclables are large, even high collection costs are supported. • When avoided costs for recyclables are not great, there are reduced opportunities for savings. • For common waste compositions, maximizing curbside recyclables collection always saves money. - Abstract: Financial analytical models of waste management systems have often found that recycling costs exceed direct benefits, and in order to economically justify recycling activities, externalities such as household expenses or environmental impacts must be invoked. Certain more empirically based studies have also found that recycling is more expensive than disposal. Other work, both through models and surveys, have found differently. Here we present an empirical systems model, largely drawn from a suburban Long Island municipality. The model accounts for changes in distribution of effort as recycling tonnages displace disposal tonnages, and the seven different cases examined all show that curbside collection programs that manage up to between 31% and 37% of the waste stream should result in overall system savings. These savings accrue partially because of assumed cost differences in tip fees for recyclables and disposed wastes, and also because recycling can result in a more efficient, cost-effective collection program. These results imply that increases in recycling are justifiable due to cost-savings alone, not on more difficult to measure factors that may not impact program budgets.

  1. Wind Farm Power System Model Development: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.

    2004-07-01

    In some areas, wind power has reached a level where it begins to impact grid operation and the stability of local utilities. In this paper, the model development for a large wind farm will be presented. Wind farm dynamic behavior and contribution to stability during transmission system faults will be examined.

  2. Building a generalized distributed system model

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.

    1992-01-01

    The key elements in the second year (1991-92) of our project are: (1) implementation of the distributed system prototype; (2) successful passing of the candidacy examination and a PhD proposal acceptance by the funded student; (3) design of storage efficient schemes for replicated distributed systems; and (4) modeling of gracefully degrading reliable computing systems. In the third year of the project (1992-93), we propose to: (1) complete the testing of the prototype; (2) enhance the functionality of the modules by enabling the experimentation with more complex protocols; (3) use the prototype to verify the theoretically predicted performance of locking protocols, etc.; and (4) work on issues related to real-time distributed systems. This should result in efficient protocols for these systems.

  3. Modeling-Enabled Systems Nutritional Immunology

    PubMed Central

    Verma, Meghna; Hontecillas, Raquel; Abedi, Vida; Leber, Andrew; Tubau-Juni, Nuria; Philipson, Casandra; Carbo, Adria; Bassaganya-Riera, Josep

    2016-01-01

    This review highlights the fundamental role of nutrition in the maintenance of health, the immune response, and disease prevention. Emerging global mechanistic insights in the field of nutritional immunology cannot be gained through reductionist methods alone or by analyzing a single nutrient at a time. We propose to investigate nutritional immunology as a massively interacting system of interconnected multistage and multiscale networks that encompass hidden mechanisms by which nutrition, microbiome, metabolism, genetic predisposition, and the immune system interact to delineate health and disease. The review sets an unconventional path to apply complex science methodologies to nutritional immunology research, discovery, and development through “use cases” centered around the impact of nutrition on the gut microbiome and immune responses. Our systems nutritional immunology analyses, which include modeling and informatics methodologies in combination with pre-clinical and clinical studies, have the potential to discover emerging systems-wide properties at the interface of the immune system, nutrition, microbiome, and metabolism. PMID:26909350

  4. Fire and materials modeling for transportation systems

    SciTech Connect

    Skocypec, R.D.; Gritzo, L.A.; Moya, J.L.; Nicolette, V.F.; Tieszen, S.R.; Thomas, R.

    1994-10-01

    Fire is an important threat to the safety of transportation systems. Therefore, understanding the effects of fire (and its interaction with materials) on transportation systems is crucial to quantifying and mitigating the impact of fire on the safety of those systems. Research and development directed toward improving the fire safety of transportation systems must address a broad range of phenomena and technologies, including: crash dynamics, fuel dispersion, fire environment characterization, material characterization, and system/cargo thermal response modeling. In addition, if the goal of the work is an assessment and/or reduction of risk due to fires, probabilistic risk assessment technology is also required. The research currently underway at Sandia National Laboratories in each of these areas is summarized in this paper.

  5. Lisp and portability: The Process Modeling System

    SciTech Connect

    Egdorf, H.W.

    1992-09-01

    A primary mission of the Technology Modeling and Assessment group (A-7) of the Analysis Division of Los Alamos National Laboratory is to support the Department of Energy in performing analysis of both existing and future facilities that comprise the Nuclear Weapons Complex. Many of the questions to be addressed in relation to this mission involve an examination of the flow of material through a processing facility and the transformations of the material as it moves through the facility by the use of a discrete-event simulation tool. In support of these analysis tasks, a simulation tool kit has been developed that allows examination of issues related to the movement and transformation of material as it moves through a processing facility. This tool kit, The Process Modeling System, is currently the primary modeling tool used for examination of current and future DOE facilities. The flexibility of the system has led to its use in performing similar analysis on a number of nonDOE facilities under Technology Transfer initiatives. The Process Modeling System is written in Common Lisp. The purpose of this paper is to describe the structure of the modeling tool kit and discuss the advantages of Common Lisp as its implementation language.

  6. Lisp and portability: The Process Modeling System

    SciTech Connect

    Egdorf, H.W.

    1992-01-01

    A primary mission of the Technology Modeling and Assessment group (A-7) of the Analysis Division of Los Alamos National Laboratory is to support the Department of Energy in performing analysis of both existing and future facilities that comprise the Nuclear Weapons Complex. Many of the questions to be addressed in relation to this mission involve an examination of the flow of material through a processing facility and the transformations of the material as it moves through the facility by the use of a discrete-event simulation tool. In support of these analysis tasks, a simulation tool kit has been developed that allows examination of issues related to the movement and transformation of material as it moves through a processing facility. This tool kit, The Process Modeling System, is currently the primary modeling tool used for examination of current and future DOE facilities. The flexibility of the system has led to its use in performing similar analysis on a number of nonDOE facilities under Technology Transfer initiatives. The Process Modeling System is written in Common Lisp. The purpose of this paper is to describe the structure of the modeling tool kit and discuss the advantages of Common Lisp as its implementation language.

  7. Active State Model for Autonomous Systems

    NASA Technical Reports Server (NTRS)

    Park, Han; Chien, Steve; Zak, Michail; James, Mark; Mackey, Ryan; Fisher, Forest

    2003-01-01

    The concept of the active state model (ASM) is an architecture for the development of advanced integrated fault-detection-and-isolation (FDI) systems for robotic land vehicles, pilotless aircraft, exploratory spacecraft, or other complex engineering systems that will be capable of autonomous operation. An FDI system based on the ASM concept would not only provide traditional diagnostic capabilities, but also integrate the FDI system under a unified framework and provide mechanism for sharing of information between FDI subsystems to fully assess the overall health of the system. The ASM concept begins with definitions borrowed from psychology, wherein a system is regarded as active when it possesses self-image, self-awareness, and an ability to make decisions itself, such that it is able to perform purposeful motions and other transitions with some degree of autonomy from the environment. For an engineering system, self-image would manifest itself as the ability to determine nominal values of sensor data by use of a mathematical model of itself, and selfawareness would manifest itself as the ability to relate sensor data to their nominal values. The ASM for such a system may start with the closed-loop control dynamics that describe the evolution of state variables. As soon as this model was supplemented with nominal values of sensor data, it would possess self-image. The ability to process the current sensor data and compare them with the nominal values would represent self-awareness. On the basis of self-image and self-awareness, the ASM provides the capability for self-identification, detection of abnormalities, and self-diagnosis.

  8. Parameter optimization in S-system models

    PubMed Central

    Vilela, Marco; Chou, I-Chun; Vinga, Susana; Vasconcelos, Ana Tereza R; Voit, Eberhard O; Almeida, Jonas S

    2008-01-01

    Background The inverse problem of identifying the topology of biological networks from their time series responses is a cornerstone challenge in systems biology. We tackle this challenge here through the parameterization of S-system models. It was previously shown that parameter identification can be performed as an optimization based on the decoupling of the differential S-system equations, which results in a set of algebraic equations. Results A novel parameterization solution is proposed for the identification of S-system models from time series when no information about the network topology is known. The method is based on eigenvector optimization of a matrix formed from multiple regression equations of the linearized decoupled S-system. Furthermore, the algorithm is extended to the optimization of network topologies with constraints on metabolites and fluxes. These constraints rejoin the system in cases where it had been fragmented by decoupling. We demonstrate with synthetic time series why the algorithm can be expected to converge in most cases. Conclusion A procedure was developed that facilitates automated reverse engineering tasks for biological networks using S-systems. The proposed method of eigenvector optimization constitutes an advancement over S-system parameter identification from time series using a recent method called Alternating Regression. The proposed method overcomes convergence issues encountered in alternate regression by identifying nonlinear constraints that restrict the search space to computationally feasible solutions. Because the parameter identification is still performed for each metabolite separately, the modularity and linear time characteristics of the alternating regression method are preserved. Simulation studies illustrate how the proposed algorithm identifies the correct network topology out of a collection of models which all fit the dynamical time series essentially equally well. PMID:18416837

  9. Modeling of pharmacokinetic systems using stochastic deconvolution.

    PubMed

    Kakhi, Maziar; Chittenden, Jason

    2013-12-01

    In environments where complete mechanistic knowledge of the system dynamics is not available, a synergy of first-principle concepts, stochastic methods and statistical approaches can provide an efficient, accurate, and insightful strategy for model development. In this work, a system of ordinary differential equations describing system pharmacokinetics (PK) was coupled to a Wiener process for tracking the absorption rate coefficient, and was embedded in a nonlinear mixed effects population PK formalism. The procedure is referred to as "stochastic deconvolution" and it is proposed as a diagnostic tool to inform on a mapping function between the fraction of the drug absorbed and the fraction of the drug dissolved when applying one-stage methods to in vitro-in vivo correlation modeling. The goal of this work was to show that stochastic deconvolution can infer an a priori specified absorption profile given dense observational (simulated) data. The results demonstrate that the mathematical model is able to accurately reproduce the simulated data in scenarios where solution strategies for linear, time-invariant systems would assuredly fail. To this end, PK systems that are representative of Michaelis-Menten kinetics and enterohepatic circulation were investigated. Furthermore, the solution times are manageable using a modest computer hardware platform.

  10. A systemic biokinetic model for polonium.

    PubMed

    Leggett, R W; Eckerman, K F

    2001-07-25

    Although the biokinetics of polonium has been studied extensively, interpretation of the data is complicated by potential differences with species and route of exposure and the questionable reliability of much of the reported excretion data for man. A study was undertaken to identify the data that are most likely to represent the typical behavior of polonium and apply those data to construct an improved, physiologically realistic systemic biokinetic model for polonium in man. Such a model is needed for interpretation of urinary excretion data for workers exposed to 210Po and reconstruction of the radiation doses received by those workers. This paper reviews the database on the biokinetics of polonium and describes a new systemic biokinetic model for polonium in man.

  11. Modeling delayed processes in biological systems

    NASA Astrophysics Data System (ADS)

    Feng, Jingchen; Sevier, Stuart A.; Huang, Bin; Jia, Dongya; Levine, Herbert

    2016-09-01

    Delayed processes are ubiquitous in biological systems and are often characterized by delay differential equations (DDEs) and their extension to include stochastic effects. DDEs do not explicitly incorporate intermediate states associated with a delayed process but instead use an estimated average delay time. In an effort to examine the validity of this approach, we study systems with significant delays by explicitly incorporating intermediate steps. We show that such explicit models often yield significantly different equilibrium distributions and transition times as compared to DDEs with deterministic delay values. Additionally, different explicit models with qualitatively different dynamics can give rise to the same DDEs revealing important ambiguities. We also show that DDE-based predictions of oscillatory behavior may fail for the corresponding explicit model.

  12. Modeling Systems Involving Interactions Between Scales

    NASA Astrophysics Data System (ADS)

    Murray, A. B.

    2005-05-01

    When we think of numerical models, `simulation modeling' often comes to mind: The modeler strives to include as many of the processes operating in the system of interest, and in as much detail, as is practical. The goal is typically to make accurate quantitative predictions. However, numerical models can also play an explanatory role. The goal of explaining a poorly understood phenomenon is often best pursued with an `exploratory' model (Murray 2002, 2003), in which a modeler minimizes the processes included and the level of detail, to try to determine what mechanisms-and what aspects of those mechanisms-are essential. These strategies are closely associated with different approaches to modeling processes across temporal and spatial scales. Simulation models often involve `explicit numerical reductionism'-the direct representation of interactions at scales as small as possible. Parameterizing sub-grid-scale processes is often seen as an unfortunate necessity, to be avoided if possible. On the other hand, when devising an exploratory model, a top-down strategy is often employed; an effort is made to represent only the effects that much smaller-scale processes have on the scale of interest. This approach allows investigation of the interactions between the emergent variables and structures that most directly explain many complex behaviors. As a caricature, we don't investigate water-wave phenomena by simulating molecular collisions. In addition, basing a model on processes at much smaller scales than those of the phenomena of interest leads to the concern that model imperfections may propagate up through the scales; that if the small-scale processes are not treated very accurately, the key interactions that emerge at larger scales may not occur as they do in the natural system. However, this risk can be bypassed by basing a model directly on larger-scale interactions, and examining which of these interactions might cause a phenomenon. For this reason, it has been

  13. Size and complexity in model financial systems.

    PubMed

    Arinaminpathy, Nimalan; Kapadia, Sujit; May, Robert M

    2012-11-01

    The global financial crisis has precipitated an increasing appreciation of the need for a systemic perspective toward financial stability. For example: What role do large banks play in systemic risk? How should capital adequacy standards recognize this role? How is stability shaped by concentration and diversification in the financial system? We explore these questions using a deliberately simplified, dynamic model of a banking system that combines three different channels for direct transmission of contagion from one bank to another: liquidity hoarding, asset price contagion, and the propagation of defaults via counterparty credit risk. Importantly, we also introduce a mechanism for capturing how swings in "confidence" in the system may contribute to instability. Our results highlight that the importance of relatively large, well-connected banks in system stability scales more than proportionately with their size: the impact of their collapse arises not only from their connectivity, but also from their effect on confidence in the system. Imposing tougher capital requirements on larger banks than smaller ones can thus enhance the resilience of the system. Moreover, these effects are more pronounced in more concentrated systems, and continue to apply, even when allowing for potential diversification benefits that may be realized by larger banks. We discuss some tentative implications for policy, as well as conceptual analogies in ecosystem stability and in the control of infectious diseases.

  14. Size and complexity in model financial systems

    PubMed Central

    Arinaminpathy, Nimalan; Kapadia, Sujit; May, Robert M.

    2012-01-01

    The global financial crisis has precipitated an increasing appreciation of the need for a systemic perspective toward financial stability. For example: What role do large banks play in systemic risk? How should capital adequacy standards recognize this role? How is stability shaped by concentration and diversification in the financial system? We explore these questions using a deliberately simplified, dynamic model of a banking system that combines three different channels for direct transmission of contagion from one bank to another: liquidity hoarding, asset price contagion, and the propagation of defaults via counterparty credit risk. Importantly, we also introduce a mechanism for capturing how swings in “confidence” in the system may contribute to instability. Our results highlight that the importance of relatively large, well-connected banks in system stability scales more than proportionately with their size: the impact of their collapse arises not only from their connectivity, but also from their effect on confidence in the system. Imposing tougher capital requirements on larger banks than smaller ones can thus enhance the resilience of the system. Moreover, these effects are more pronounced in more concentrated systems, and continue to apply, even when allowing for potential diversification benefits that may be realized by larger banks. We discuss some tentative implications for policy, as well as conceptual analogies in ecosystem stability and in the control of infectious diseases. PMID:23091020

  15. Modeling Power System Operation with Intermittent Resources

    SciTech Connect

    Marinovici, Maria C.; Kirkham, Harold; Glass, Kevin A.; Carlsen, Leif C.

    2013-02-27

    Electricity generating companies and power system operators face the need to minimize total fuel cost or maximize total profit over a given time period. These issues become optimization problems subject to a large number of constraints that must be satisfied simultaneously. The grid updates due to smart-grid technologies plus the penetration of intermittent re- sources in electrical grid introduce additional complexity to the optimization problem. The Renewable Integration Model (RIM) is a computer model of interconnected power system. It is intended to provide insight and advice on complex power systems management, as well as answers to integration of renewable energy questions. This paper describes RIM basic design concept, solution method, and the initial suite of modules that it supports.

  16. Advanced Technology System Scheduling Governance Model

    SciTech Connect

    Ang, Jim; Carnes, Brian; Hoang, Thuc; Vigil, Manuel

    2015-06-11

    In the fall of 2005, the Advanced Simulation and Computing (ASC) Program appointed a team to formulate a governance model for allocating resources and scheduling the stockpile stewardship workload on ASC capability systems. This update to the original document takes into account the new technical challenges and roles for advanced technology (AT) systems and the new ASC Program workload categories that must be supported. The goal of this updated model is to effectively allocate and schedule AT computing resources among all three National Nuclear Security Administration (NNSA) laboratories for weapons deliverables that merit priority on this class of resource. The process outlined below describes how proposed work can be evaluated and approved for resource allocations while preserving high effective utilization of the systems. This approach will provide the broadest possible benefit to the Stockpile Stewardship Program (SSP).

  17. Proposed Modification to the Plutonium Systemic Model.

    PubMed

    Konzen, Kevin; Miller, Scott; Brey, Richard

    2015-10-01

    The currently accepted biokinetic model for plutonium distribution within the human body was recommended by the International Commission on Radiological Protection in publication 67. This model was developed from human and animal studies and behavioral knowledge acquired from other known bone-seeking radionuclides. The biokinetic model provides a mathematical means of predicting the distribution, retention, and clearance of plutonium within the human body that may be used in deriving organ, tissue, and whole body dose. This work proposed a modification to the ICRP 67 systemic model for plutonium that incorporated the latest knowledge acquired from recent human injection studies with physiologically based improvements. In summary, the changes included a separation of the liver compartments, removed the intermediate soft tissue-to-bladder pathway, and added pathways from the blood compartment to both the cortical and trabecular bone volumes. The proposed model provided improved predictions for several bioassay indicators compared to the ICRP 67 model while also maintaining its basic structure. Additionally, the proposed model incorporated physiologically based improvements for the liver and skeleton and continued to ensure efficient coupling with intake biokinetic models.

  18. Climate Model Diagnostic Analyzer Web Service System

    NASA Astrophysics Data System (ADS)

    Lee, S.; Pan, L.; Zhai, C.; Tang, B.; Jiang, J. H.

    2013-12-01

    The latest Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report stressed the need for the comprehensive and innovative evaluation of climate models with newly available global observations. The traditional approach to climate model evaluation, which compares a single parameter at a time, identifies symptomatic model biases and errors but fails to diagnose the model problems. The model diagnosis process requires physics-based multi-variable comparisons that typically involve large-volume and heterogeneous datasets, making them both computationally- and data-intensive. To address these challenges, we are developing a parallel, distributed web-service system that enables the physics-based multi-variable model performance evaluations and diagnoses through the comprehensive and synergistic use of multiple observational data, reanalysis data, and model outputs. We have developed a methodology to transform an existing science application code into a web service using a Python wrapper interface and Python web service frameworks (i.e., Flask, Gunicorn, and Tornado). The web-service system, called Climate Model Diagnostic Analyzer (CMDA), currently supports (1) all the datasets from Obs4MIPs and a few ocean datasets from NOAA and Argo, which can serve as observation-based reference data for model evaluation and (2) many of CMIP5 model outputs covering a broad range of atmosphere, ocean, and land variables from the CMIP5 specific historical runs and AMIP runs. Analysis capabilities currently supported by CMDA are (1) the calculation of annual and seasonal means of physical variables, (2) the calculation of time evolution of the means in any specified geographical region, (3) the calculation of correlation between two variables, and (4) the calculation of difference between two variables. A web user interface is chosen for CMDA because it not only lowers the learning curve and removes the adoption barrier of the tool but also enables instantaneous use

  19. Aircraft system modeling error and control error

    NASA Technical Reports Server (NTRS)

    Kulkarni, Nilesh V. (Inventor); Kaneshige, John T. (Inventor); Krishnakumar, Kalmanje S. (Inventor); Burken, John J. (Inventor)

    2012-01-01

    A method for modeling error-driven adaptive control of an aircraft. Normal aircraft plant dynamics is modeled, using an original plant description in which a controller responds to a tracking error e(k) to drive the component to a normal reference value according to an asymptote curve. Where the system senses that (1) at least one aircraft plant component is experiencing an excursion and (2) the return of this component value toward its reference value is not proceeding according to the expected controller characteristics, neural network (NN) modeling of aircraft plant operation may be changed. However, if (1) is satisfied but the error component is returning toward its reference value according to expected controller characteristics, the NN will continue to model operation of the aircraft plant according to an original description.

  20. Causal Model of a Health Services System

    PubMed Central

    Anderson, James G.

    1972-01-01

    Path analysis is used to construct a causal model of the health services system serving the state of New Mexico. The model includes a network specifying the causal relationships among a set of social, demographic, and economic variables hypothesized to be related to the health status of the population; a set of mathematical equations that permit prediction of the effects of changes in the values of any one variable on all other variables in the model; and estimates of path coefficients based on U.S. Census data and vital statistics. The model is used to predict both direct and indirect effects on health status of changes in population structure resulting from natural causes or from the intervention of health programs. PMID:5025955

  1. System and mathematical modeling of quadrotor dynamics

    NASA Astrophysics Data System (ADS)

    Goodman, Jacob M.; Kim, Jinho; Gadsden, S. Andrew; Wilkerson, Stephen A.

    2015-05-01

    Unmanned aerial systems (UAS) are becoming increasingly visible in our daily lives; and range in operation from search and rescue, monitoring hazardous environments, and to the delivery of goods. One of the most popular UAS are based on a quad-rotor design. These are typically small devices that rely on four propellers for lift and movement. Quad-rotors are inherently unstable, and rely on advanced control methodologies to keep them operating safely and behaving in a predictable and desirable manner. The control of these devices can be enhanced and improved by making use of an accurate dynamic model. In this paper, we examine a simple quadrotor model, and note some of the additional dynamic considerations that were left out. We then compare simulation results of the simple model with that of another comprehensive model.

  2. Modelling magmatic gas scrubbing in hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Di Napoli, Rossella; Aiuppa, Alessandro; Valenza, Mariano; Bergsson, Baldur; Ilyinskaya, Evgenia; Pfeffer, Melissa Anne; Rakel Guðjónsdóttir, Sylvía

    2015-04-01

    In volcano-hosted hydrothermal systems, the chemistry of deeply rising magmatic gases is extensively modified by gas-water-rock interactions taking place within the hydrothermal reservoir, and/or at shallow groundwaters conditions. These reactions can scrub reactive, water-soluble species (S, halogens) from the magmatic gas phase, so that their quantitative assessment is central to understanding the chemistry of surface gas manifestations, and brings profound implications to the interpretation of volcanic-hydrothermal unrests. Here, we present the results of numerical simulations of magmatic gas scrubbing, in which the reaction path modelling approach (Helgeson, 1968) is used to reproduce hydrothermal gas-water-rock interactions at both shallow (temperature up to 109°C; low-T model runs) and deep reservoir (temperature range: 150-250 °C; high-T model runs) conditions. The model was built based upon the EQ3/6 software package (Wolery and Daveler, 1992), and consisted into a step by step addition of a high-temperature magmatic gas to an initial meteoric water, in the presence of a dissolving aquifer rock. The model outputted, at each step of gas addition, the chemical composition of a new aqueous solution formed after gas-water-rock interactions; which, upon reaching gas over-pressuring (PgasTOT > Psat(H2O) at run T), is degassed (by single-step degassing) to separate a scrubbed gas phase. As an application of the model results, the model compositions of the separated gases are finally compared with compositions of natural gas emissions from Hekla volcano (T< 100°C) and from Krisuvik geothermal system (T> 100°C), resulting into an excellent agreement. The compositions of the model solutions are also in fair agreement with compositions of natural thermal water samples. We conclude that our EQ3/6-based reaction path simulations offer a realistic representation of gas-water-rock interaction processes occurring underneath active magmatic-hydrothermal systems

  3. Using the TSAR electromagnetic modeling system

    NASA Astrophysics Data System (ADS)

    Pennock, S. T.; Laguna, G. W.

    1993-09-01

    A new user, upon receipt of the TSAR EM modeling system, may be overwhelmed by the number of software packages to learn and the number of manuals associated with those packages. This is a document to describe the creation of a simple TSAR model, beginning with an MGED solid and continuing the process through final results from TSAR. It is not intended to be a complete description of all the parts of the TSAR package. Rather, it is intended simply to touch on all the steps in the modeling process and to take a new user through the system from start to finish. There are six basic parts to the TSAR package. The first, MGED, is part of the BRL-CAD package and is used to create a solid model. The second part, ANASTASIA, is the program used to sample the solid model and create a finite-difference mesh. The third program, IMAGE, lets the user view the mesh itself and verify its accuracy. If everything about the mesh is correct, the process continues to the fourth step, SETUP-TSAR, which creates the parameter files for compiling TSAR and the input file for running a particular simulation. The fifth step is actually running TSAR, the field modeling program. Finally, the output from TSAR is placed into SIG, B2RAS or another program for post-processing and plotting. Each of these steps will be described below. The best way to learn to use the TSAR software is to actually create and run a simple test problem. As an example of how to use the TSAR package, let's create a sphere with a rectangular internal cavity, with conical and cylindrical penetrations connecting the outside to the inside, and find the electric field inside the cavity when the object is exposed to a Gaussian plane wave. We will begin with the solid modeling software, MGED, a part of the BRL-CAD modeling release.

  4. Using a System Model for Irrigation Management

    NASA Astrophysics Data System (ADS)

    de Souza, Leonardo; de Miranda, Eu; Sánchez-Román, Rodrigo; Orellana-González, Alba

    2014-05-01

    When using Systems Thinking variables involved in any process have a dynamic behavior, according to nonstatic relationships with the environment. In this paper it is presented a system dynamics model developed to be used as an irrigation management tool. The model involves several parameters related to irrigation such as: soil characteristics, climate data and culture's physiological parameters. The water availability for plants in the soil is defined as a stock in the model, and this soil water content will define the right moment to irrigate and the water depth required to be applied. The crop water consumption will reduce soil water content; it is defined by the potential evapotranspiration (ET) that acts as an outflow from the stock (soil water content). ET can be estimated by three methods: a) FAO Penman-Monteith (ETPM), b) Hargreaves-Samani (ETHS) method, based on air temperature data and c) Class A pan (ETTCA) method. To validate the model were used data from the States of Ceará and Minas Gerais, Brazil, and the culture was bean. Keyword: System Dynamics, soil moisture content, agricultural water balance, irrigation scheduling.

  5. Photochemistry of Model Organic Aerosol Systems

    NASA Astrophysics Data System (ADS)

    Mang, S. A.; Bateman, A. P.; Dailo, M.; Do, T.; Nizkorodov, S. A.; Pan, X.; Underwood, J. S.; Walser, M. L.

    2007-05-01

    Up to 90 percent of urban aerosol particles have been shown to contain organic molecules. Reactions of these particles with atmospheric oxidants and/or sunlight result in large changes in their composition, toxicity, and ability to act as cloud condensation nuclei. For this reason, chemistry of model organic aerosol particles initiated by oxidation and direct photolysis is of great interest to atmospheric, climate, and health scientists. Most studies in this area have focused on identifying the products of oxidation of the organic aerosols, while the products of direct photolysis of the resulting molecules remaining in the aerosol particle have been left mostly unexplored. We have explored direct photolytic processes occurring in selected organic aerosol systems using infrared cavity ringdown spectroscopy to identify small gas phase products of photolysis, and mass-spectrometric and photometric techniques to study the condensed phase products. The first model system was secondary organic aerosol formed from the oxidation of several monoterpenes by ozone in the presence and absence of NOx, under different humidities. The second system modeled after oxidatively aged primary organic aerosol particles was a thin film of either alkanes or saturated fatty acids oxidized in several different ways, with the oxidation initiated by ozone, chlorine atom, or OH. In every case, the general conclusion was that the photochemical processing of model organic aerosols is significant. Such direct photolysis processes are believed to age organic aerosol particles on time scales that are short compared to the particles' atmospheric lifetimes.

  6. Cost effectiveness of recycling: a systems model.

    PubMed

    Tonjes, David J; Mallikarjun, Sreekanth

    2013-11-01

    Financial analytical models of waste management systems have often found that recycling costs exceed direct benefits, and in order to economically justify recycling activities, externalities such as household expenses or environmental impacts must be invoked. Certain more empirically based studies have also found that recycling is more expensive than disposal. Other work, both through models and surveys, have found differently. Here we present an empirical systems model, largely drawn from a suburban Long Island municipality. The model accounts for changes in distribution of effort as recycling tonnages displace disposal tonnages, and the seven different cases examined all show that curbside collection programs that manage up to between 31% and 37% of the waste stream should result in overall system savings. These savings accrue partially because of assumed cost differences in tip fees for recyclables and disposed wastes, and also because recycling can result in a more efficient, cost-effective collection program. These results imply that increases in recycling are justifiable due to cost-savings alone, not on more difficult to measure factors that may not impact program budgets.

  7. Model reduction of systems with localized nonlinearities.

    SciTech Connect

    Segalman, Daniel Joseph

    2006-03-01

    An LDRD funded approach to development of reduced order models for systems with local nonlinearities is presented. This method is particularly useful for problems of structural dynamics, but has potential application in other fields. The key elements of this approach are (1) employment of eigen modes of a reference linear system, (2) incorporation of basis functions with an appropriate discontinuity at the location of the nonlinearity. Galerkin solution using the above combination of basis functions appears to capture the dynamics of the system with a small basis set. For problems involving small amplitude dynamics, the addition of discontinuous (joint) modes appears to capture the nonlinear mechanics correctly while preserving the modal form of the predictions. For problems involving large amplitude dynamics of realistic joint models (macro-slip), the use of appropriate joint modes along with sufficient basis eigen modes to capture the frequencies of the system greatly enhances convergence, though the modal nature the result is lost. Also observed is that when joint modes are used in conjunction with a small number of elastic eigen modes in problems of macro-slip of realistic joint models, the resulting predictions are very similar to those of the full solution when seen through a low pass filter. This has significance both in terms of greatly reducing the number of degrees of freedom of the problem and in terms of facilitating the use of much larger time steps.

  8. Cosmic emergy based ecological systems modelling

    NASA Astrophysics Data System (ADS)

    Chen, H.; Chen, G. Q.; Ji, X.

    2010-09-01

    Ecological systems modelling based on the unified biophysical measure of cosmic emergy in terms of embodied cosmic exergy is illustrated in this paper with ecological accounting, simulation and scenario analysis, by a case study for the regional socio-economic ecosystem associated with the municipality of Beijing. An urbanized regional ecosystem model with eight subsystems of natural support, agriculture, urban production, population, finance, land area, potential environmental impact, and culture is representatively presented in exergy circuit language with 12 state variables governing by corresponding ecodynamic equations, and 60 flows and auxiliary variables. To characterize the regional socio-economy as an ecosystem, a series of ecological indicators based on cosmic emergy are devised. For a systematic ecological account, cosmic exergy transformities are provided for various dimensions including climate flows, natural resources, industrial products, cultural products, population with educational hierarchy, and environmental emissions. For the urban ecosystem of Beijing in the period from 1990 to 2005, ecological accounting is carried out and characterized in full details. Taking 2000 as the starting point, systems modelling is realized to predict the urban evolution in a one hundred time horizon. For systems regulation, scenario analyses with essential policy-making implications are made to illustrate the long term systems effects of the expected water diversion and rise in energy price.

  9. Common world model for unmanned systems

    NASA Astrophysics Data System (ADS)

    Dean, Robert Michael S.

    2013-05-01

    The Robotic Collaborative Technology Alliance (RCTA) seeks to provide adaptive robot capabilities which move beyond traditional metric algorithms to include cognitive capabilities. Key to this effort is the Common World Model, which moves beyond the state-of-the-art by representing the world using metric, semantic, and symbolic information. It joins these layers of information to define objects in the world. These objects may be reasoned upon jointly using traditional geometric, symbolic cognitive algorithms and new computational nodes formed by the combination of these disciplines. The Common World Model must understand how these objects relate to each other. Our world model includes the concept of Self-Information about the robot. By encoding current capability, component status, task execution state, and histories we track information which enables the robot to reason and adapt its performance using Meta-Cognition and Machine Learning principles. The world model includes models of how aspects of the environment behave, which enable prediction of future world states. To manage complexity, we adopted a phased implementation approach to the world model. We discuss the design of "Phase 1" of this world model, and interfaces by tracing perception data through the system from the source to the meta-cognitive layers provided by ACT-R and SS-RICS. We close with lessons learned from implementation and how the design relates to Open Architecture.

  10. Model Reduction for Control System Design

    NASA Technical Reports Server (NTRS)

    Enns, D. F.

    1985-01-01

    An approach and a technique for effectively obtaining reduced order mathematical models of a given large order model for the purposes of synthesis, analysis and implementation of control systems is developed. This approach involves the use of an error criterion which is the H-infinity norm of a frequency weighted error between the full and reduced order models. The weightings are chosen to take into account the purpose for which the reduced order model is intended. A previously unknown error bound in the H-infinity norm for reduced order models obtained from internally balanced realizations was obtained. This motivated further development of the balancing technique to include the frequency dependent weightings. This resulted in the frequency weighted balanced realization and a new model reduction technique. Two approaches to designing reduced order controllers were developed. The first involves reducing the order of a high order controller with an appropriate weighting. The second involves linear quadratic Gaussian synthesis based on a reduced order model obtained with an appropriate weighting.

  11. Videogrammetric Model Deformation Measurement System User's Manual

    NASA Technical Reports Server (NTRS)

    Dismond, Harriett R.

    2002-01-01

    The purpose of this manual is to provide the user of the NASA VMD system, running the MDef software, Version 1.10, all information required to operate the system. The NASA Videogrammetric Model Deformation system consists of an automated videogrammetric technique used to measure the change in wing twist and bending under aerodynamic load in a wind tunnel. The basic instrumentation consists of a single CCD video camera and a frame grabber interfaced to a computer. The technique is based upon a single view photogrammetric determination of two-dimensional coordinates of wing targets with fixed (and known) third dimensional coordinate, namely the span-wise location. The major consideration in the development of the measurement system was that productivity must not be appreciably reduced.

  12. Single timepoint models of dynamic systems.

    PubMed

    Sachs, K; Itani, S; Fitzgerald, J; Schoeberl, B; Nolan, G P; Tomlin, C J

    2013-08-01

    Many interesting studies aimed at elucidating the connectivity structure of biomolecular pathways make use of abundance measurements, and employ statistical and information theoretic approaches to assess connectivities. These studies often do not address the effects of the dynamics of the underlying biological system, yet dynamics give rise to impactful issues such as timepoint selection and its effect on structure recovery. In this work, we study conditions for reliable retrieval of the connectivity structure of a dynamic system, and the impact of dynamics on structure-learning efforts. We encounter an unexpected problem not previously described in elucidating connectivity structure from dynamic systems, show how this confounds structure learning of the system and discuss possible approaches to overcome the confounding effect. Finally, we test our hypotheses on an accurate dynamic model of the IGF signalling pathway. We use two structure-learning methods at four time points to contrast the performance and robustness of those methods in terms of recovering correct connectivity. PMID:24511382

  13. Development and application of earth system models.

    PubMed

    Prinn, Ronald G

    2013-02-26

    The global environment is a complex and dynamic system. Earth system modeling is needed to help understand changes in interacting subsystems, elucidate the influence of human activities, and explore possible future changes. Integrated assessment of environment and human development is arguably the most difficult and most important "systems" problem faced. To illustrate this approach, we present results from the integrated global system model (IGSM), which consists of coupled submodels addressing economic development, atmospheric chemistry, climate dynamics, and ecosystem processes. An uncertainty analysis implies that without mitigation policies, the global average surface temperature may rise between 3.5 °C and 7.4 °C from 1981-2000 to 2091-2100 (90% confidence limits). Polar temperatures, absent policy, are projected to rise from about 6.4 °C to 14 °C (90% confidence limits). Similar analysis of four increasingly stringent climate mitigation policy cases involving stabilization of greenhouse gases at various levels indicates that the greatest effect of these policies is to lower the probability of extreme changes. The IGSM is also used to elucidate potential unintended environmental consequences of renewable energy at large scales. There are significant reasons for attention to climate adaptation in addition to climate mitigation that earth system models can help inform. These models can also be applied to evaluate whether "climate engineering" is a viable option or a dangerous diversion. We must prepare young people to address this issue: The problem of preserving a habitable planet will engage present and future generations. Scientists must improve communication if research is to inform the public and policy makers better.

  14. Development and application of earth system models.

    PubMed

    Prinn, Ronald G

    2013-02-26

    The global environment is a complex and dynamic system. Earth system modeling is needed to help understand changes in interacting subsystems, elucidate the influence of human activities, and explore possible future changes. Integrated assessment of environment and human development is arguably the most difficult and most important "systems" problem faced. To illustrate this approach, we present results from the integrated global system model (IGSM), which consists of coupled submodels addressing economic development, atmospheric chemistry, climate dynamics, and ecosystem processes. An uncertainty analysis implies that without mitigation policies, the global average surface temperature may rise between 3.5 °C and 7.4 °C from 1981-2000 to 2091-2100 (90% confidence limits). Polar temperatures, absent policy, are projected to rise from about 6.4 °C to 14 °C (90% confidence limits). Similar analysis of four increasingly stringent climate mitigation policy cases involving stabilization of greenhouse gases at various levels indicates that the greatest effect of these policies is to lower the probability of extreme changes. The IGSM is also used to elucidate potential unintended environmental consequences of renewable energy at large scales. There are significant reasons for attention to climate adaptation in addition to climate mitigation that earth system models can help inform. These models can also be applied to evaluate whether "climate engineering" is a viable option or a dangerous diversion. We must prepare young people to address this issue: The problem of preserving a habitable planet will engage present and future generations. Scientists must improve communication if research is to inform the public and policy makers better. PMID:22706645

  15. Firn modelling in the Community Earth System Model (CESM)

    NASA Astrophysics Data System (ADS)

    van Kampenhout, Leo; Lenaerts, Jan; Sacks, William; Lipscomb, William; van den Broeke, Michiel

    2016-04-01

    Firn meltwater retention and refreezing controls the magnitude and timing of surface runoff, which is the largest contributor of the Greenland freshwater transport into its neighbouring oceans. In Antarctica, all meltwater refreezes, but the sensitivity of ice shelf stability to atmospheric warming is strongly dependent on the amount of firn air. In this study we use the land-only version of the Community Earth System Model (CESM), forced by ERA-Interim reanalysis (1979-present) to simulate the firn air content over both ice sheets. The impact of three key parameters is examined: (1) the density of freshly fallen snow, (2) the modelled maximum depth of the firn and (3) the compaction rate by overburden pressure. An evaluation of our model results with available firn core observations shows that we can improve the representation of the ice sheet firn, which renders CESM suitable to study the long-term response of ice sheet firn to climate change.

  16. Aircraft engine mathematical model - linear system approach

    NASA Astrophysics Data System (ADS)

    Rotaru, Constantin; Roateşi, Simona; Cîrciu, Ionicǎ

    2016-06-01

    This paper examines a simplified mathematical model of the aircraft engine, based on the theory of linear and nonlinear systems. The dynamics of the engine was represented by a linear, time variant model, near a nominal operating point within a finite time interval. The linearized equations were expressed in a matrix form, suitable for the incorporation in the MAPLE program solver. The behavior of the engine was included in terms of variation of the rotational speed following a deflection of the throttle. The engine inlet parameters can cover a wide range of altitude and Mach numbers.

  17. Overembedding Method for Modeling Nonstationary Systems

    SciTech Connect

    Verdes, P.F.

    2006-03-24

    We propose a general overembedding method for modeling and prediction of nonstationary systems. It basically enlarges the standard time-delay-embedding space by inclusion of the (unknown) slow driving signal, which is estimated simultaneously with the intrinsic stationary dynamics. Our method can be implemented with any modeling tool. Using, in particular, artificial neural networks, its application to both synthetic and real-world time series shows that it is highly efficient, leading to much more accurate results and longer prediction horizons than other existing overembedding methods in the literature.

  18. Controlled Ecological Life Support System (CELSS) modeling

    NASA Technical Reports Server (NTRS)

    Drysdale, Alan; Thomas, Mark; Fresa, Mark; Wheeler, Ray

    1992-01-01

    Attention is given to CELSS, a critical technology for the Space Exploration Initiative. OCAM (object-oriented CELSS analysis and modeling) models carbon, hydrogen, and oxygen recycling. Multiple crops and plant types can be simulated. Resource recovery options from inedible biomass include leaching, enzyme treatment, aerobic digestion, and mushroom and fish growth. The benefit of using many small crops overlapping in time, instead of a single large crop, is demonstrated. Unanticipated results include startup transients which reduce the benefit of multiple small crops. The relative contributions of mass, energy, and manpower to system cost are analyzed in order to determine appropriate research directions.

  19. Phase Transitions in Model Active Systems

    NASA Astrophysics Data System (ADS)

    Redner, Gabriel S.

    The amazing collective behaviors of active systems such as bird flocks, schools of fish, and colonies of microorganisms have long amazed scientists and laypeople alike. Understanding the physics of such systems is challenging due to their far-from-equilibrium dynamics, as well as the extreme diversity in their ingredients, relevant time- and length-scales, and emergent phenomenology. To make progress, one can categorize active systems by the symmetries of their constituent particles, as well as how activity is expressed. In this work, we examine two categories of active systems, and explore their phase behavior in detail. First, we study systems of self-propelled spherical particles moving in two dimensions. Despite the absence of an aligning interaction, this system displays complex emergent dynamics, including phase separation into a dense active solid and dilute gas. Using simulations and analytic modeling, we quantify the phase diagram and separation kinetics. We show that this nonequilibrium phase transition is analogous to an equilibrium vapor-liquid system, with binodal and spinodal curves and a critical point. We also characterize the dense active solid phase, a unique material which exhibits the structural signatures of a crystalline solid near the crystal-hexatic transition point, as well as anomalous dynamics including superdiffusive motion on intermediate timescales. We also explore the role of interparticle attraction in this system. We demonstrate that attraction drastically changes the phase diagram, which contains two distinct phase-separated regions and is reentrant as a function of propulsion speed. We interpret this complex situation with a simple kinetic model, which builds from the observed microdynamics of individual particles to a full description of the macroscopic phase behavior. We also study active nematics, liquid crystals driven out of equilibrium by energy-dissipating active stresses. The equilibrium nematic state is unstable in these

  20. Some queuing network models of computer systems

    NASA Technical Reports Server (NTRS)

    Herndon, E. S.

    1980-01-01

    Queuing network models of a computer system operating with a single workload type are presented. Program algorithms are adapted for use on the Texas Instruments SR-52 programmable calculator. By slightly altering the algorithm to process the G and H matrices row by row instead of column by column, six devices and an unlimited job/terminal population could be handled on the SR-52. Techniques are also introduced for handling a simple load dependent server and for studying interactive systems with fixed multiprogramming limits.

  1. Informing Decisions with Earth System Models

    NASA Astrophysics Data System (ADS)

    Lempert, R. J.

    2012-12-01

    The emerging generation of earth system models offers the potential for significant improvements in region planning in the face of interlinked environmental and socio-economic changes. But these models also raise important questions about how to best use the information they contain to support decision-making, particularly in the face of the considerable uncertainty in many model projections. The decision support literature provides general guidance on this challenge, with its emphasize on the importance of grounding information provision in user needs, the importance of focusing on decision-making processes, and need to design for learning. This talk will build on this guidance to suggest an approach for using Earth System Models to inform regional planning decisions. In brief, this robust decision making approach suggests beginning with one or more specific plans (for instance, a specific regional plan and its supporting policies and investments), running the model many times to explore the performance of the plan in many potential future conditions, uses cluster analysis on the resulting database of model results to identify those conditions where a plan may fail to meet its goals, and then use this information to help decision-makers to consider and chose among potential modifications to their plans. This approach provides an effective means to characterize uncertainty and link to policy-makers' decision processes. In particular, it can support the development of adaptive policies designed to evolve over time in response to new information. This talk will demonstrate these approaches using examples from regional water management and discuss how one can use them to evaluate the value of different types of model-supplied information.

  2. An L-system model for root system mycorrhization

    NASA Astrophysics Data System (ADS)

    Schnepf, Andrea; Schweiger, Peter; Jansa, Jan; Leitner, Daniel

    2014-05-01

    Mineral phosphate fertilisers are a non-renewable resource; rock phosphate reserves are estimated to be depleted in 50 to 100 years. In order to prevent a severe phosphate crisis in the 21st century, there is a need to decrease agricultural inputs such as P fertilisers by making use of plant mechanisms that increase P acquisition efficiency. Most plants establish mycorrhizal symbiosis as an adaptation to increase/economize their P acquisition from the soil. However, there is a great functional diversity in P acquisition mechanisms among different fungal species that colonize the roots (Thonar et al. 2011), and the composition of mycorrhizal community is known to depend strongly on agricultural management practices. Thus, the agroecosystem management may substantially affect the mycorrhizal functioning and also the use of P fertilizers. To date, it is still difficult to quantify the potential input savings for the agricultural crops through manipulation of their symbiotic microbiome, mainly due to lack of mechanistic understanding of P uptake dynamics by the fungal hyphae. In a first attempt, Schnepf et al. (2008b) have used mathematical modelling to show on the single root scale how different fungal growth pattern influence root P uptake. However, their approach was limited by the fact that it was restricted to the scale of a single root. The goal of this work is to advance the dynamic, three-dimensional root architecture model of Leitner et al. (2010) to include root system infection with arbuscular mycorrhizal fungi and growth of external mycelium. The root system infection model assumes that there is an average probability of infection (primary infection), that the probability of infection of a new root segment immediately adjacent to an existing infection is much higher than the average (secondary infection), that infected root segments have entry points that are the link between internal and external mycelium, that only uninfected root segments are susceptible

  3. Multiregion contact systems for modelling STD epidemics.

    PubMed

    Thomas, R; Smith, T E

    This paper elicits properties of some multiregional contact systems for STD infections that are intended to assist the understanding of disease control strategies. To this end, a space-time SIS model is described that maintains the symmetry of contact that is inherent in the formation of sexual partnerships. It is demonstrated how the characteristic stability conditions of this model provide a framework for understanding the potential for sustained transmission after the introduction of the agent into a given region. Then, more complex SI specifications are derived that are particularly relevant to the transmission of HIV. These extensions include the introduction of alternative modes of travel and behavioural adaptations made in response to the circulation of HIV and the incidence of AIDS. The discussion suggests some additions to the systems that might enhance their applicability in practice.

  4. Workshop on electric utility systems modeling

    SciTech Connect

    Prasad, R.; Kittur, R.; Walker, R.; Marten, D.

    1992-01-01

    The primary objective of this workshop is to obtain a clear understanding of the various details involved in developing electric utility models from public-domain information. The workshop is aimed at providing a thorough tutorial and a hands-on exercise in developing a set of relational databases that can be used to analyze the behavior of selected power systems. Because of several modeling details that can be utility-specific, issues that are common among all systems need to be addressed. These common issues include: Data collection from public-domain sources; generation of connectivity diagrams; generation/load/tie-line MW assignments; parameter database creation (.DAT); development of one-line database (.OL); development of geographic database (.GEO); error-checking between databases; development of power-flow data files (.DCD and IEE); and power-flow analysis

  5. Workshop on electric utility systems modeling

    SciTech Connect

    Prasad, R.; Kittur, R.; Walker, R.; Marten, D.

    1992-12-31

    The primary objective of this workshop is to obtain a clear understanding of the various details involved in developing electric utility models from public-domain information. The workshop is aimed at providing a thorough tutorial and a hands-on exercise in developing a set of relational databases that can be used to analyze the behavior of selected power systems. Because of several modeling details that can be utility-specific, issues that are common among all systems need to be addressed. These common issues include: Data collection from public-domain sources; generation of connectivity diagrams; generation/load/tie-line MW assignments; parameter database creation (.DAT); development of one-line database (.OL); development of geographic database (.GEO); error-checking between databases; development of power-flow data files (.DCD and IEE); and power-flow analysis

  6. Towards a community Earth System Model

    NASA Astrophysics Data System (ADS)

    Blackmon, M.

    2003-04-01

    The Community Climate System Model, version 2 (CCSM2), was released in June 2002. CCSM2 has several new components and features, which I will discuss briefly. I will also show a few results from a multi-century equilibrium run with this model, emphasizing the improvements over the earlier simulation using the original CSM. A few flaws and inadequacies in CCSM2 have been identified. I will also discuss briefly work underway to improve the model and present results, if available. CCSM2, with improvements, will be the basis for the development of a Community Earth System Model (CESM). The highest priority for expansion of the model involves incorporation of biogeosciences into the coupled model system, with emphasis given to the carbon, nitrogen and iron cycles. The overall goal of the biogeosciences project within CESM is to understand the regulation of planetary energetics, planetary ecology, and planetary metabolism through exchanges of energy, momentum, and materials among atmosphere, land, and ocean, and the response of the climate system through these processes to changes in land cover and land use. In particular, this research addresses how biogeochemical coupling of carbon, nitrogen, and iron cycles affects climate and how human perturbations of these cycles alter climate. To accomplish these goals, the Community Land Model, the land component of CCSM2, is being developed to include river routing, carbon and nitrogen cycles, emissions of mineral aerosols and biogenic volatile organic compounds, dry deposition of various gases, and vegetation dynamics. The carbon and nitrogen cycles are being implemented using parameterizations developed as part of a state-of-the-art ecosystem biogeochemistry model. The primary goal of this research is to provide an accurate net flux of CO2 between the land and the atmosphere so that CESM can be used to study the dynamics of the coupled climate-carbon system. Emissions of biogenic volatile organic compounds are also based on a

  7. Rupture dynamics in model polymer systems.

    PubMed

    Borah, Rupam; Debnath, Pallavi

    2016-05-11

    In this paper we explore the rupture dynamics of a model polymer system to capture the microscopic mechanism during relative motion of surfaces at the single polymer level. Our model is similar to the model for friction introduced by Filippov, Klafter, and Urbakh [Filippov et al., Phys. Rev. Lett., 2004, 92, 135503]; but with an important generalization to a flexible transducer (modelled as a bead spring polymer) which is attached to a fixed rigid planar substrate by interconnecting bonds (modelled as harmonic springs), and pulled by a constant force FT. Bonds are allowed to rupture stochastically. The model is simulated, and the results for a certain set of parameters exhibit a sequential rupture mechanism resulting in rupture fronts. A mean field formalism is developed to study these rupture fronts and the possible propagating solutions for the coupled bead and bond dynamics, where the coupling excludes an exact analytical treatment. Numerical solutions to mean field equations are obtained by standard numerical techniques, and they agree well with the simulation results which show sequential rupture. Within a travelling wave formalism based on the Tanh method, we show that the velocity of the rupture front can be obtained in closed form. The derived expression for the rupture front velocity gives good agreement with the stochastic and mean field results, when the rupture is sequential, while propagating solutions for bead and bond dynamics are shown to agree under certain conditions. PMID:27087684

  8. Development and application of earth system models

    PubMed Central

    Prinn, Ronald G.

    2013-01-01

    The global environment is a complex and dynamic system. Earth system modeling is needed to help understand changes in interacting subsystems, elucidate the influence of human activities, and explore possible future changes. Integrated assessment of environment and human development is arguably the most difficult and most important “systems” problem faced. To illustrate this approach, we present results from the integrated global system model (IGSM), which consists of coupled submodels addressing economic development, atmospheric chemistry, climate dynamics, and ecosystem processes. An uncertainty analysis implies that without mitigation policies, the global average surface temperature may rise between 3.5 °C and 7.4 °C from 1981–2000 to 2091–2100 (90% confidence limits). Polar temperatures, absent policy, are projected to rise from about 6.4 °C to 14 °C (90% confidence limits). Similar analysis of four increasingly stringent climate mitigation policy cases involving stabilization of greenhouse gases at various levels indicates that the greatest effect of these policies is to lower the probability of extreme changes. The IGSM is also used to elucidate potential unintended environmental consequences of renewable energy at large scales. There are significant reasons for attention to climate adaptation in addition to climate mitigation that earth system models can help inform. These models can also be applied to evaluate whether “climate engineering” is a viable option or a dangerous diversion. We must prepare young people to address this issue: The problem of preserving a habitable planet will engage present and future generations. Scientists must improve communication if research is to inform the public and policy makers better. PMID:22706645

  9. The Community Climate System Model: CCSM3

    SciTech Connect

    Collins, W D; Blackmon, M; Bitz, C; Bonan, G; Bretherton, C S; Carton, J A; Chang, P; Doney, S; Hack, J J; Kiehl, J T; Henderson, T; Large, W G; McKenna, D; Santer, B D; Smith, R D

    2004-12-27

    A new version of the Community Climate System Model (CCSM) has been developed and released to the climate community. CCSM3 is a coupled climate model with components representing the atmosphere, ocean, sea ice, and land surface connected by a flux coupler. CCSM3 is designed to produce realistic simulations over a wide range of spatial resolutions, enabling inexpensive simulations lasting several millennia or detailed studies of continental-scale climate change. This paper will show results from the configuration used for climate-change simulations with a T85 grid for atmosphere and land and a 1-degree grid for ocean and sea-ice. The new system incorporates several significant improvements in the scientific formulation. The enhancements in the model physics are designed to reduce or eliminate several systematic biases in the mean climate produced by previous editions of CCSM. These include new treatments of cloud processes, aerosol radiative forcing, land-atmosphere fluxes, ocean mixed-layer processes, and sea-ice dynamics. There are significant improvements in the sea-ice thickness, polar radiation budgets, equatorial sea-surface temperatures, ocean currents, cloud radiative effects, and ENSO teleconnections. CCSM3 can produce stable climate simulations of millenial duration without ad hoc adjustments to the fluxes exchanged among the component models. Nonetheless, there are still systematic biases in the ocean-atmosphere fluxes in western coastal regions, the spectrum of ENSO variability, the spatial distribution of precipitation in the Pacific and Indian Oceans, and the continental precipitation and surface air temperatures. We conclude with the prospects for extending CCSM to a more comprehensive model of the Earth's climate system.

  10. Modelling of Integrated Renewable Energy System

    NASA Astrophysics Data System (ADS)

    Akella, A. K.; Saini, R. P.; Sharma, M. P.

    2007-10-01

    Energy is supplied in the form of electricity, heat or fuels and an energy supply system must guarantee sufficient production and distribution of energy. An energy supply system based on renewable energy can be utilized as integrated renewable energy system (IRES), which can satisfy the energy needs of an area in appropriate & sustainable manner. Given the key role of renewable energy in rural electrification of remote rural areas, the IRES for a given area can be modeled & optimized for meeting the energy needs. In the present paper, Jaunpur block of Uttaranchal state of India has been selected as remote area. Based upon the data collected, the resource potential and energy demand has been calculated & presented. The model on the basis of unit cost of the energy has been optimized using LINDO software 6.10 version. The results indicated that the optimized model has been found to the best choice for meeting the energy needs of the area. The results further indicated that for the above area, either an IRES consisting of the above sources can provide a feasible solution in terms of energy fulfillments in the range of EPDF from 1.0 to 0.75.

  11. Adaptive model training system and method

    DOEpatents

    Bickford, Randall L; Palnitkar, Rahul M

    2014-11-18

    An adaptive model training system and method for filtering asset operating data values acquired from a monitored asset for selectively choosing asset operating data values that meet at least one predefined criterion of good data quality while rejecting asset operating data values that fail to meet at least the one predefined criterion of good data quality; and recalibrating a previously trained or calibrated model having a learned scope of normal operation of the asset by utilizing the asset operating data values that meet at least the one predefined criterion of good data quality for adjusting the learned scope of normal operation of the asset for defining a recalibrated model having the adjusted learned scope of normal operation of the asset.

  12. Adaptive model training system and method

    DOEpatents

    Bickford, Randall L; Palnitkar, Rahul M; Lee, Vo

    2014-04-15

    An adaptive model training system and method for filtering asset operating data values acquired from a monitored asset for selectively choosing asset operating data values that meet at least one predefined criterion of good data quality while rejecting asset operating data values that fail to meet at least the one predefined criterion of good data quality; and recalibrating a previously trained or calibrated model having a learned scope of normal operation of the asset by utilizing the asset operating data values that meet at least the one predefined criterion of good data quality for adjusting the learned scope of normal operation of the asset for defining a recalibrated model having the adjusted learned scope of normal operation of the asset.

  13. VIIP: Central Nervous System (CNS) Modeling

    NASA Technical Reports Server (NTRS)

    Vera, Jerry; Mulugeta, Lealem; Nelson, Emily; Raykin, Julia; Feola, Andrew; Gleason, Rudy; Samuels, Brian; Ethier, C. Ross; Myers, Jerry

    2015-01-01

    Current long-duration missions to the International Space Station and future exploration-class missions beyond low-Earth orbit expose astronauts to increased risk of Visual Impairment and Intracranial Pressure (VIIP) syndrome. It has been hypothesized that the headward shift of cerebrospinal fluid (CSF) and blood in microgravity may cause significant elevation of intracranial pressure (ICP), which in turn may then induce VIIP syndrome through interaction with various biomechanical pathways. However, there is insufficient evidence to confirm this hypothesis. In this light, we are developing lumped-parameter models of fluid transport in the central nervous system (CNS) as a means to simulate the influence of microgravity on ICP. The CNS models will also be used in concert with the lumped parameter and finite element models of the eye described in the related IWS works submitted by Nelson et al., Feola et al. and Ethier et al.

  14. Software systems for modeling articulated figures

    NASA Technical Reports Server (NTRS)

    Phillips, Cary B.

    1989-01-01

    Research in computer animation and simulation of human task performance requires sophisticated geometric modeling and user interface tools. The software for a research environment should present the programmer with a powerful but flexible substrate of facilities for displaying and manipulating geometric objects, yet insure that future tools have a consistent and friendly user interface. Jack is a system which provides a flexible and extensible programmer and user interface for displaying and manipulating complex geometric figures, particularly human figures in a 3D working environment. It is a basic software framework for high-performance Silicon Graphics IRIS workstations for modeling and manipulating geometric objects in a general but powerful way. It provides a consistent and user-friendly interface across various applications in computer animation and simulation of human task performance. Currently, Jack provides input and control for applications including lighting specification and image rendering, anthropometric modeling, figure positioning, inverse kinematics, dynamic simulation, and keyframe animation.

  15. World Energy Projection System model documentation

    SciTech Connect

    Hutzler, M.J.; Anderson, A.T.

    1997-09-01

    The World Energy Projection System (WEPS) was developed by the Office of Integrated Analysis and Forecasting within the Energy Information Administration (EIA), the independent statistical and analytical agency of the US Department of Energy. WEPS is an integrated set of personal computer based spreadsheets containing data compilations, assumption specifications, descriptive analysis procedures, and projection models. The WEPS accounting framework incorporates projections from independently documented models and assumptions about the future energy intensity of economic activity (ratios of total energy consumption divided by gross domestic product GDP), and about the rate of incremental energy requirements met by natural gas, coal, and renewable energy sources (hydroelectricity, geothermal, solar, wind, biomass, and other renewable resources). Projections produced by WEPS are published in the annual report, International Energy Outlook. This report documents the structure and procedures incorporated in the 1998 version of the WEPS model. It has been written to provide an overview of the structure of the system and technical details about the operation of each component of the model for persons who wish to know how WEPS projections are produced by EIA.

  16. Multidimensional Learner Model In Intelligent Learning System

    NASA Astrophysics Data System (ADS)

    Deliyska, B.; Rozeva, A.

    2009-11-01

    The learner model in an intelligent learning system (ILS) has to ensure the personalization (individualization) and the adaptability of e-learning in an online learner-centered environment. ILS is a distributed e-learning system whose modules can be independent and located in different nodes (servers) on the Web. This kind of e-learning is achieved through the resources of the Semantic Web and is designed and developed around a course, group of courses or specialty. An essential part of ILS is learner model database which contains structured data about learner profile and temporal status in the learning process of one or more courses. In the paper a learner model position in ILS is considered and a relational database is designed from learner's domain ontology. Multidimensional modeling agent for the source database is designed and resultant learner data cube is presented. Agent's modules are proposed with corresponding algorithms and procedures. Multidimensional (OLAP) analysis guidelines on the resultant learner module for designing dynamic learning strategy have been highlighted.

  17. Modelling of virtual home robot system

    NASA Astrophysics Data System (ADS)

    Lu, Desheng; Hong, Bingrong

    2004-10-01

    The approach of the computional simulation in the virtual prototyping is applied to design the system of home robot. By means of three-dimensional (3-D) real scene modeling, the virtual enviroment of family rooms and 3-D entity models of virtual home robot are established on Silicon graphics workstation. The kinematics model of home robot is derived for degree of freedom motions. The scenes of the virtual enviroment are changing with the movements of the observer"s viewpoint. So the 3-D scenes can simulate the images taken by the camera as the viewpoint of the channel is set on the camera of virtual home robot. The data of the odometer is simulated by the parameters that label the numbers of wheels" rotations. In order to verify feasibility of the virtual home robot system, the simulation experiment is presented as the virtual home robot roaming in the virtual environment of family rooms. The geometric model of each part of home robot is articulated as a node tree to be put into the virtual enviroment. The results of the experiments show that the technology of virtual prototype can lead good synergy between the fields of virtual reality and Robotics.

  18. A Systems Model for Power Technology Assessment

    NASA Technical Reports Server (NTRS)

    Hoffman, David J.

    2002-01-01

    A computer model is under continuing development at NASA Glenn Research Center that enables first-order assessments of space power technology. The model, an evolution of NASA Glenn's Array Design Assessment Model (ADAM), is an Excel workbook that consists of numerous spreadsheets containing power technology performance data and sizing algorithms. Underlying the model is a number of databases that contain default values for various power generation, energy storage and power management and distribution component parameters. These databases are actively maintained by a team of systems analysts so that they contain state-of-art data as well as the most recent technology performance projections. Sizing of the power subsystems can be accomplished either by using an assumed mass specific power (W/kg) or energy (Wh/kg) or by a bottoms-up calculation that accounts for individual component performance and masses. The power generation, energy storage and power management and distribution subsystems are sized for given mission requirements for a baseline case and up to three alternatives. This allows four different power systems to be sized and compared using consistent assumptions and sizing algorithms. The component sizing models contained in the workbook are modular so that they can be easily maintained and updated. All significant input values have default values loaded from the databases that can be over-written by the user. The default data and sizing algorithms for each of the power subsystems are described in some detail. The user interface and workbook navigational features are also discussed. Finally, an example study case that illustrates the model's capability is presented.

  19. Modeling and analysis of energy conversion systems

    SciTech Connect

    Den Braven, K.R. . Dept. of Mechanical Engineering); Stanger, S. )

    1990-10-01

    An investigation was conducted to assess the need for and the feasibility of developing a computer code that could model thermodynamic systems and predict the performance of energy conversion systems. To assess the market need for this code, representatives of a few industrial organizations were contacted, including manufacturers, system and component designers, and research personnel. Researchers and small manufacturers, designers, and installers were very interested in the possibility of using the proposed code. However, large companies were satisfied with the existing codes that they have developed for their own use. Also, a survey was conduced of available codes that could be used or possibly modified for the desired purpose. The codes were evaluated with respect to a list of desirable features, which was prepared as a result of the survey. A few publicly available codes were found that might be suitable. The development, verification, and maintenance of such a code would require a substantial, ongoing effort. 21 refs.

  20. Future Challenges of Modeling THMC Systems

    NASA Astrophysics Data System (ADS)

    Miller, S. A.; Heinze, T.; Hamidi, S.; Galvan, B.

    2014-12-01

    Fracture-fluid flow coupling is critical for understanding society-relevant energy sources such as Enhanced Geothermal Systems (EGS), hydrocarbon extraction via hydraulic fracture, and carbon capture and storage (CCS). Although fluid-rock interactions are one of the most important processes in lithospheric geodynamics, they are one of the most difficult to properly simulate because of the orders-of-magnitude changes in hydraulic properties at the onset of fracture or slip. These large-scale changes in hydraulic properties result in the locally rapid flow that is likely to react with their new surroundings. Advances in modeling these processes must properly modeling the evolution of fracture networks coupled to the hydraulic (and thermodynamic) properties within the advecting, over-pressured, and reactive system. Many THM simulators exist but with limited utility because their inherently low resolution do not allow for the development of evolving fracture networks. A promising approach to modeling is to develop algorithms written in the CUDA programming language and optimized for computations using the inherently parallel Graphics Processing Unit (GPU) computer architecture. We are developing such a model, with target resolutions on the order of 1000x1000x 500. This simulator models a pore-elastic-thermo-elastic-plastic rheology that includes hardening, softening, and damage, and coupled to a non-linear diffusion model of fluid pressure and a 2-phase fluid (water and gas). Both tensile and shear fractures evolve in response to far-field stresses, local stress perturbations associated with both shear and tensile fractures, and thermo-elastic and pore-elastic stresses. The advantage of this model over existing models is that the governing equations have been reformulated to run on a GPU cluster. Results from numerical experiments show that this approach has great potential to study fluid-rock interactions at all scales. In this talk, I summarize the progress to date

  1. Modeling Physical Systems Using Vensim PLE Systems Dynamics Software

    NASA Astrophysics Data System (ADS)

    Widmark, Stephen

    2012-02-01

    Many physical systems are described by time-dependent differential equations or systems of such equations. This makes it difficult for students in an introductory physics class to solve many real-world problems since these students typically have little or no experience with this kind of mathematics. In my high school physics classes, I address this problem by having my students use a variety of software solutions to model physical systems described by differential equations. These include spreadsheets, applets, software my students themselves create, and systems dynamics software. For the latter, cost is often the main issue in choosing a solution for use in a public school and so I researched no-cost software. I found Sphinx SD,2OptiSim,3 Systems Dynamics,4 Simile (Trial Edition),5 and Vensim PLE.6 In evaluating each of these solutions, I looked for the fewest restrictions in the license for educational use, ease of use by students, power, and versatility. In my opinion, Vensim PLE best fulfills these criteria.7

  2. Earth system modelling: a GAIM perspective

    NASA Astrophysics Data System (ADS)

    Prentice, C.

    2003-04-01

    For over a decade the IGBP Task Force on Global Analysis, Integration (formerly Interepretation) and Modelling (GAIM) has facilitated international, interdisciplinary research. The focus has been development, comparison and evaluation of models describing Earth system components, especially terrestrial and ocean carbon cycling and atmospheric transport. GAIM also sponsored the BIOME 6000 project, which produced snapshots of world vegetation patterns for the last glacial maximum (LGM) and mid-Holocene, and experiments in coupled atmosphere-biosphere modelling that used these results. The most successful achievements have brought together modellers and data experts so that model comparisons could be made “with open eyes”. The need to bring together different communities (such as data experts and modellers; ecologists and atmospheric scientists; economists and ecologists...) only increases, and is a major rationale for the continuation of GAIM. GAIM has recently set out 23 overarching questions which could define future directions in Earth system science. Many have a “human dimension”, reflecting the fact that the societal context is poorly defined. Natural scientists often appeal to societal reasons to study global change, but typically don’t incorporate human science perspectives in their research strategies. Other questions have a “physical dimension” as biogeochemistry, atmospheric chemistry and physical climate science merge. As IGBP II begins, GAIM faces the challenge of tackling large gaps in our knowledge of how the coupled Earth system works, with and without human interfence. On the natural science side, the Vostok ice-core record dramatically illustrates our current state of ignorance. Vostok established that the Earth system’s response to orbital forcing is characterized by strong non-linear interactions between atmospheric greenhouse-gas and aerosol constituents and climate. The problem is that we don’t understand most of these

  3. Climate Model Diagnostic Analyzer Web Service System

    NASA Astrophysics Data System (ADS)

    Lee, S.; Pan, L.; Zhai, C.; Tang, B.; Jiang, J. H.

    2014-12-01

    We have developed a cloud-enabled web-service system that empowers physics-based, multi-variable model performance evaluations and diagnoses through the comprehensive and synergistic use of multiple observational data, reanalysis data, and model outputs. We have developed a methodology to transform an existing science application code into a web service using a Python wrapper interface and Python web service frameworks. The web-service system, called Climate Model Diagnostic Analyzer (CMDA), currently supports (1) all the observational datasets from Obs4MIPs and a few ocean datasets from NOAA and Argo, which can serve as observation-based reference data for model evaluation, (2) many of CMIP5 model outputs covering a broad range of atmosphere, ocean, and land variables from the CMIP5 specific historical runs and AMIP runs, and (3) ECMWF reanalysis outputs for several environmental variables in order to supplement observational datasets. Analysis capabilities currently supported by CMDA are (1) the calculation of annual and seasonal means of physical variables, (2) the calculation of time evolution of the means in any specified geographical region, (3) the calculation of correlation between two variables, (4) the calculation of difference between two variables, and (5) the conditional sampling of one physical variable with respect to another variable. A web user interface is chosen for CMDA because it not only lowers the learning curve and removes the adoption barrier of the tool but also enables instantaneous use, avoiding the hassle of local software installation and environment incompatibility. CMDA will be used as an educational tool for the summer school organized by JPL's Center for Climate Science in 2014. In order to support 30+ simultaneous users during the school, we have deployed CMDA to the Amazon cloud environment. The cloud-enabled CMDA will provide each student with a virtual machine while the user interaction with the system will remain the same

  4. System Modeling for Ammonia Synthesis Energy Recovery System

    NASA Astrophysics Data System (ADS)

    Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Ammonia thermochemical Energy Storage Team

    2015-11-01

    An ammonia thermochemical energy storage system is an alternative solution to the state-of-the-art molten salt TES system for concentrating solar power. Some of the advantages of this emerging technology include its high energy density, no heat losses during the storage duration, and the possibility of long storage periods. Solar energy powers an endothermic reaction to disassociate ammonia into hydrogen and nitrogen, which can be stored for future use. The reverse reaction is carried out in the energy recovery process; a hydrogen-nitrogen mixture flowing through a catalyst bed undergoes the exothermic ammonia synthesis reaction. The goal is to use the ammonia synthesis reaction to heat supercritical steam to temperatures on the order of 650°C as required for a supercritical steam Rankine cycle. The steam will flow through channels in a combined reactor-heat exchanger. A numerical model has been developed to determine the optimal design to heat supercritical steam while maintaining a stable exothermic reaction. The model consists of a transient one dimensional concentric tube counter-flow reactor-heat exchanger. The numerical model determines the inlet mixture conditions needed to achieve various steam outlet conditions.

  5. Advanced Space Propulsion System Flowfield Modeling

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon

    1998-01-01

    Solar thermal upper stage propulsion systems currently under development utilize small low chamber pressure/high area ratio nozzles. Consequently, the resulting flow in the nozzle is highly viscous, with the boundary layer flow comprising a significant fraction of the total nozzle flow area. Conventional uncoupled flow methods which treat the nozzle boundary layer and inviscid flowfield separately by combining the two calculations via the influence of the boundary layer displacement thickness on the inviscid flowfield are not accurate enough to adequately treat highly viscous nozzles. Navier Stokes models such as VNAP2 can treat these flowfields but cannot perform a vacuum plume expansion for applications where the exhaust plume produces induced environments on adjacent structures. This study is built upon recently developed artificial intelligence methods and user interface methodologies to couple the VNAP2 model for treating viscous nozzle flowfields with a vacuum plume flowfield model (RAMP2) that is currently a part of the Plume Environment Prediction (PEP) Model. This study integrated the VNAP2 code into the PEP model to produce an accurate, practical and user friendly tool for calculating highly viscous nozzle and exhaust plume flowfields.

  6. Osmosis in a minimal model system.

    PubMed

    Lion, Thomas W; Allen, Rosalind J

    2012-12-28

    Osmosis is one of the most important physical phenomena in living and soft matter systems. While the thermodynamics of osmosis is well understood, the underlying microscopic dynamical mechanisms remain the subject of discussion. Unravelling these mechanisms is a prerequisite for understanding osmosis in non-equilibrium systems. Here, we investigate the microscopic basis of osmosis, in a system at equilibrium, using molecular dynamics simulations of a minimal model in which repulsive solute and solvent particles differ only in their interactions with an external potential. For this system, we can derive a simple virial-like relation for the osmotic pressure. Our simulations support an intuitive picture in which the solvent concentration gradient, at osmotic equilibrium, arises from the balance between an outward force, caused by the increased total density in the solution, and an inward diffusive flux caused by the decreased solvent density in the solution. While more complex effects may occur in other osmotic systems, our results suggest that they are not required for a minimal picture of the dynamic mechanisms underlying osmosis.

  7. Osmosis in a minimal model system.

    PubMed

    Lion, Thomas W; Allen, Rosalind J

    2012-12-28

    Osmosis is one of the most important physical phenomena in living and soft matter systems. While the thermodynamics of osmosis is well understood, the underlying microscopic dynamical mechanisms remain the subject of discussion. Unravelling these mechanisms is a prerequisite for understanding osmosis in non-equilibrium systems. Here, we investigate the microscopic basis of osmosis, in a system at equilibrium, using molecular dynamics simulations of a minimal model in which repulsive solute and solvent particles differ only in their interactions with an external potential. For this system, we can derive a simple virial-like relation for the osmotic pressure. Our simulations support an intuitive picture in which the solvent concentration gradient, at osmotic equilibrium, arises from the balance between an outward force, caused by the increased total density in the solution, and an inward diffusive flux caused by the decreased solvent density in the solution. While more complex effects may occur in other osmotic systems, our results suggest that they are not required for a minimal picture of the dynamic mechanisms underlying osmosis. PMID:23277960

  8. Osmosis in a minimal model system

    NASA Astrophysics Data System (ADS)

    Lion, Thomas W.; Allen, Rosalind J.

    2012-12-01

    Osmosis is one of the most important physical phenomena in living and soft matter systems. While the thermodynamics of osmosis is well understood, the underlying microscopic dynamical mechanisms remain the subject of discussion. Unravelling these mechanisms is a prerequisite for understanding osmosis in non-equilibrium systems. Here, we investigate the microscopic basis of osmosis, in a system at equilibrium, using molecular dynamics simulations of a minimal model in which repulsive solute and solvent particles differ only in their interactions with an external potential. For this system, we can derive a simple virial-like relation for the osmotic pressure. Our simulations support an intuitive picture in which the solvent concentration gradient, at osmotic equilibrium, arises from the balance between an outward force, caused by the increased total density in the solution, and an inward diffusive flux caused by the decreased solvent density in the solution. While more complex effects may occur in other osmotic systems, our results suggest that they are not required for a minimal picture of the dynamic mechanisms underlying osmosis.

  9. Kinetic modelling of krypton fluoride laser systems

    SciTech Connect

    Jancaitis, K.S.

    1983-11-01

    A kinetic model has been developed for the KrF* rare gas halide laser system, specifically for electron-beam pumped mixtures of krypton, fluorine, and either helium or argon. The excitation produced in the laser gas by the e-beam was calculated numerically using an algorithm checked by comparing the predicted ionization yields in the pure rare gases with their experimental values. The excitation of the laser media by multi-kilovolt x-rays was also modeled and shown to be similar to that produced by high energy electrons. A system of equations describing the transfer of the initial gas excitation into the laser upper level was assembled using reaction rate constants from both experiment and theory. A one-dimensional treatment of the interaction of the laser radiation with the gas was formulated which considered spontaneous and stimulated emission and absorption. The predictions of this model were in good agreement with the fluorescence signals and gain and absorption measured experimentally.

  10. Risk management model in road transport systems

    NASA Astrophysics Data System (ADS)

    Sakhapov, R. L.; Nikolaeva, R. V.; Gatiyatullin, M. H.; Makhmutov, M. M.

    2016-08-01

    The article presents the results of a study of road safety indicators that influence the development and operation of the transport system. Road safety is considered as a continuous process of risk management. Authors constructed a model that relates the social risks of a major road safety indicator - the level of motorization. The model gives a fairly accurate assessment of the level of social risk for any given level of motorization. Authors calculated the dependence of the level of socio-economic costs of accidents and injured people in them. The applicability of the concept of socio-economic damage is caused by the presence of a linear relationship between the natural and economic indicators damage from accidents. The optimization of social risk is reduced to finding the extremum of the objective function that characterizes the economic effect of the implementation of measures to improve safety. The calculations make it possible to maximize the net present value, depending on the costs of improving road safety, taking into account socio-economic damage caused by accidents. The proposed econometric models make it possible to quantify the efficiency of the transportation system, allow to simulate the change in road safety indicators.

  11. Modeling the protection system components of the Space Station electric power system

    NASA Astrophysics Data System (ADS)

    Tam, Kwa-Sur; Yang, Lifeng; Dravid, Narayan

    1994-07-01

    To facilitate protection system studies on the space station electric power system, there is a need to develop a model that can accurately and conveniently simulate both the power system and the protection system. Models for two major protective devices, the remote bus isolater and the remote power controller, are described. These models have been installed in a power system model resembling one channel of the space station power system. The usefulness of these models in protection system studies is demonstrated.

  12. Peptide neuromodulation in invertebrate model systems

    PubMed Central

    Taghert, Paul H.; Nitabach, Michael N.

    2012-01-01

    Neuropeptides modulate neural circuits controlling adaptive animal behaviors and physiological processes, such as feeding/metabolism, reproductive behaviors, circadian rhythms, central pattern generation, and sensorimotor integration. Invertebrate model systems have enabled detailed experimental analysis using combined genetic, behavioral, and physiological approaches. Here we review selected examples of neuropeptide modulation in crustaceans, mollusks, insects, and nematodes, with a particular emphasis on the genetic model organisms Drosophila melanogaster and Caenorhabditis elegans, where remarkable progress has been made. On the basis of this survey, we provide several integrating conceptual principles for understanding how neuropeptides modulate circuit function, and also propose that continued progress in this area requires increased emphasis on the development of richer, more sophisticated behavioral paradigms. PMID:23040808

  13. A GUI for Modeling Multiple Planet Systems

    NASA Astrophysics Data System (ADS)

    Giguere, Matthew J.; Ader, T.; Barnes, R.; Barranco, J. A.; Fischer, D.

    2009-01-01

    We developed an IDL widget interface (MPF Widget) to model planetary systems using combined astrometric and radial velocity data. MPF Widget drives a Levenberg-Marquardt fitting algorithm to simultaneously fit data for parallax, proper motion and up to seven planets. This visualization tool is helpful for locating good initial guesses that allow the Levenberg-Marquardt fitting algorithm to converge on the global minimum chi squared value. It also includes tools for periodogram analysis and the capability to fit planets sequentially working with the residual data from each preceding model. MPF Widget was developed to test simulated data for the Space Interferometry Mission (SIM) and would be a useful tool for teaching the effects of each Keplerian parameter on observational data. We thank NASA and SIM for supporting this project.

  14. Transcendental Political Systems and the Gravity Model

    NASA Technical Reports Server (NTRS)

    Lock, Connor

    2012-01-01

    This summer I have been working on an Army Deep Futures Model project named Themis. Themis is a JPL based modeling framework that anticipates possible future states for the world within the next 25 years. The goal of this framework is to determine the likelihood that the US Army will need to intervene on behalf of the US strategic interests. Key elements that are modeled within this tool include the world structure and major decisions that are made by key actors. Each actor makes decisions based on their goals and within the constraints of the structure of the system in which they are located. In my research I have focused primarily on the effects of structures upon the decision-making processes of the actors within them. This research is a natural extension of my major program at Georgetown University, where I am studying the International Political Economy and the structures that make it up. My basic goal for this summer project was to be a helpful asset to the Themis modeling team, with any research done or processes learned constituting a bonus.

  15. Clover development during spaceflight: A model system

    NASA Technical Reports Server (NTRS)

    Guikema, James A.; Debell, Lynnette; Paulsen, Avelina; Spooner, Brian S.; Wong, Peter P.

    1994-01-01

    The development of legume root nodules was studied as a model system for the examination of gravitational effects on plant root development. In order to examine whether rhizobial association with clover roots can be achieved in microgravity, experiments were performed aboard the KC-135 parabolic aircraft and aboard the sounding rocket mission Consort 3. Binding of rhizobia to roots and the initial stages of root nodule development successfully occurred in microgravity. Seedling germination experiments were performed in the sliding block device, the Materials Dispersion Apparatus, aboard STS-37. When significant hydration of the seeds was achieved, normal rates of germination and seedling development were observed.

  16. A space transportation system operations model

    NASA Technical Reports Server (NTRS)

    Morris, W. Douglas; White, Nancy H.

    1987-01-01

    Presented is a description of a computer program which permits assessment of the operational support requirements of space transportation systems functioning in both a ground- and space-based environment. The scenario depicted provides for the delivery of payloads from Earth to a space station and beyond using upper stages based at the station. Model results are scenario dependent and rely on the input definitions of delivery requirements, task times, and available resources. Output is in terms of flight rate capabilities, resource requirements, and facility utilization. A general program description, program listing, input requirements, and sample output are included.

  17. Spatial Analysis and Modeling Systems (SAMS)

    NASA Technical Reports Server (NTRS)

    Vermillion, Charles; Chan, Paul; Hill, John; Jaske, Robert; Rochon, Gilbert; Stetina, Fran

    1991-01-01

    The objective is to develop a uniform environmental data gathering and distribution system to support (1) emergency management for environmental disasters, and (2) the calibration and validation of remotely sensed data. Initial activities will be to select a data test site and to demonstrate multi-discipline applications using simulated or satellite data in a non real-time mode. Rainfall and flooding are chosen as the testbeds for the SAMS concept because of the abundance of data and the availability of models. The capability to display and process GOES data and analyze GOES generated rain-rate maps will be integrated into SAMS.

  18. Clover development during spaceflight: a model system.

    PubMed

    Guikema, J A; DeBell, L; Paulsen, A; Spooner, B S; Wong, P P

    1994-01-01

    The development of legume root nodules was studied as a model system for the examination of gravitational effects on plant root development. In order to examine whether rhizobial association with clover roots can be achieved in microgravity, experiments were performed aboard the KC-135 parabolic aircraft and aboard the sounding rocket mission Consort 3. Binding of rhizobia to roots and the initial stages of root nodule development successfully occurred in microgravity. Seedling germination experiments were performed in the sliding block device, the Materials Dispersion Apparatus, aboard STS-37. When significant hydration of the seeds was achieved, normal rates of germination and seedling development were observed. PMID:11537915

  19. Modeling unmanned system collaborative target engagement

    NASA Astrophysics Data System (ADS)

    Jaenisch, Holger M.; Handley, James W.; Hicklen, Michael L.

    2007-04-01

    This paper describes a novel algorithm for collaborative target engagement by unmanned systems (UMS) resulting in emergent behavior. We demonstrate UMS collaborative engagement using a simulation testbed model of a road, convoy vehicles traveling along the road, a squadron of unmanned aerial vehicles (UAVs), and multiple unmanned ground vehicles (UGVs) which are set to detonate when within close proximity to a convoy vehicle. No explicit artificial intelligence or swarming algorithms were used. Collision avoidance was an intrinsic phenomena. All entities acted independently throughout the simulation, but were given similar local instructions for possible courses of action (COAs) depending on current situations. Our algorithm and results are summarized in this paper.

  20. Modeling Earth system changes of the past

    NASA Technical Reports Server (NTRS)

    Kutzbach, John E.

    1992-01-01

    This review outlines some of the challenging problems to be faced in understanding the causes and mechanisms of large climatic changes and gives examples of initial studies of these problems with climate models. The review covers climatic changes in three main periods of earth history: (1) the past several centuries; (2) the past several glacial-interglacial cycles; and (3) the past several million years. The review will concentrate on studies of climate but, where possible, will mention broader aspects of the earth system.

  1. Fabric-based systems: model, tools, applications.

    SciTech Connect

    Wolinski, C.; Gokhale, M.; McCabe, K. P.

    2003-01-01

    A Fabric Based System is a parameterized cellular architecture in which an array of computing cells communicates with an embedded processor through a global memory . This architecture is customizable to different classes of applications by funtional unit, interconnect, and memory parameters, and can be instantiated efficiently on platform FPGAs . In previous work, we have demonstrated the advantage of reconfigurable fabrics for image and signal processing applications . Recently, we have build a Fabric Generator, a Java-based toolset that greatly accelerates construction of the fabrics presented in. A module-generation library is used to define, instantiate, and interconnect cells' datapaths . FG generates customized sequencers for individual cells or collections of cells . We describe the Fabric-Based System model, the FG toolset, and concrete realizations offabric architectures generated by FG on the Altera Excalibur ARM that can deliver 4.5 GigaMACs/s (8/16 bit data, Multiply-Accumulate) .

  2. MODELING VENTILATION SYSTEM RESPONSE TO FIRE

    SciTech Connect

    Coutts, D

    2007-04-17

    Fires in facilities containing nuclear material have the potential to transport radioactive contamination throughout buildings and may lead to widespread downwind dispersal threatening both worker and public safety. Development and implementation of control strategies capable of providing adequate protection from fire requires realistic characterization of ventilation system response which, in turn, depends on an understanding of fire development timing and suppression system response. This paper discusses work in which published HEPA filter data was combined with CFAST fire modeling predictions to evaluate protective control strategies for a hypothetical DOE non-reactor nuclear facility. The purpose of this effort was to evaluate when safety significant active ventilation coupled with safety class passive ventilation might be a viable control strategy.

  3. Context in Models of Human-Machine Systems

    NASA Technical Reports Server (NTRS)

    Callantine, Todd J.; Null, Cynthia H. (Technical Monitor)

    1998-01-01

    All human-machine systems models represent context. This paper proposes a theory of context through which models may be usefully related and integrated for design. The paper presents examples of context representation in various models, describes an application to developing models for the Crew Activity Tracking System (CATS), and advances context as a foundation for integrated design of complex dynamic systems.

  4. Early Solar System Leftovers: Testing Solar System Formation Models

    NASA Astrophysics Data System (ADS)

    Meech, Karen Jean; Yang, Bin; Kleyna, Jan; Hainaut, Olivier R.; Keane, Jacqueline V.; Micheli, Marco; Berdyugina, Svetlana; Bhatt, Bhuwan; Sahu, Devendra; Hsieh, Henry; Veres, Peter; Wainscoat, Richard J.; Riesen, Timm-Emanuel; Kaluna, Heather

    2015-11-01

    One of the most intriguing predictions of the Grand Tack model is the presence of volatile poor objects in the Oort cloud that were swept from the region where the terrestrial planets formed. This volatile-poor material is represented today by ordinary chondrites, enstatite chondrites and differentiated planetesimals. These are the main constituents of the S-type asteroids that reside in the inner Solar system. According to the Grand Tack model, the fraction of S-type material in cometary orbits should be around 0.1-0.2%. Recent Pan-STARRS 1 discoveries of objects on long-period comet orbits that are minimally active while at small perihelia have suggested the intriguing possibility that these could potentially represent inner solar system material that was ejected into the outer solar system during planet migration, that is now making its way back in. The first object discovered, C/2013 P2 has a spectrum redder than D-type objects, but exhibits low-level activity throughout its perihelion passage. The second one, C/2014 S3, appears to have an S-type asteroid spectrum, and likewise exhibits low-level activity.Nearly 100 of these objects have now been identified, approximately half of which are still observable, and more are being discovered. We will report on observations made for a selection of these objects with several facilities including Gemini N 8 m, VLT 8 m, Canada-France-Hawaii 3.6 m, PS1 2 m, UH2.2 m, HCT 2 m, and the Lowell 1.8 m telescopes. We will discuss the implications of seeing volatile activity in these objects.

  5. Structural Modeling of Network Systems in Citation Analysis.

    ERIC Educational Resources Information Center

    Yaru, Dang

    1997-01-01

    Describes construction of citation network systems and some subsystems (time sequence network, cocitation network, couple network). Establishes structural modeling of these systems by means of system engineering. Explains and analyzes citation network systems. Includes graphs and charts. (JAK)

  6. Nematode model systems in evolution and development.

    PubMed

    Sommer, Ralf J; Bumbarger, Daniel J

    2012-01-01

    The free-living nematode Caenorhabditis elegans is one of the most important model organisms in all areas of modern biology. Using the knowledge about C. elegans as a baseline, nematodes are now intensively studied in evolution and development. Evolutionary developmental biology or for short, 'evo-devo' has been developed as a new research discipline during the last two decades to investigate how changes in developmental processes and mechanisms result in the modification of morphological structures and phenotypic novelty. In this article, we review the concepts that make nematode evo-devo a successful approach to evolutionary biology. We introduce selected model systems for nematode evo-devo and provide a detailed discussion of four selected case studies. The most striking finding of nematode evo-devo is the magnitude of developmental variation in the context of a conserved body plan. Detailed investigation of early embryogenesis, gonad formation, vulva development, and sex determination revealed that molecular mechanisms evolve rapidly, often in the context of a conserved body plan. These studies highlight the importance of developmental systems drift and neutrality in evolution. PMID:23801489

  7. Modeling Topaz-II system performance

    SciTech Connect

    Lee, H.H.; Klein, A.C. )

    1993-01-01

    The US acquisition of the Topaz-11 in-core thermionic space reactor test system from Russia provides a good opportunity to perform a comparison of the Russian reported data and the results from computer codes such as MCNP (Ref. 3) and TFEHX (Ref. 4). The comparison study includes both neutronic and thermionic performance analyses. The Topaz II thermionic reactor is modeled with MCNP using actual Russian dimensions and parameters. The computation of the neutronic performance considers several important aspects such as the fuel enrichment and location of the thermionic fuel elements (TFES) in the reactor core. The neutronic analysis included the calculation of both radial and axial power distribution, which are then used in the TFEHX code for electrical performance. The reactor modeled consists of 37 single-cell TFEs distributed in a 13-cm-radius zirconium hydride block surrounded by 8 cm of beryllium metal reflector. The TFEs use 90% enriched [sup 235]U and molybdenum coated with a thin layer of [sup 184]W for emitter surface. Electrons emitted are captured by a collector surface with a gap filled with cesium vapor between the collector and emitter surfaces. The collector surface is electrically insulated with alumina. Liquid NaK provides the cooling system for the TFEs. The axial thermal power distribution is obtained by dividing the TFE into 40 axial nodes. Comparison of the true axial power distribution with that produced by electrical heaters was also performed.

  8. Control of breathing in invertebrate model systems.

    PubMed

    Bell, Harold J; Syed, Naweed I

    2012-07-01

    The invertebrates have adopted a myriad of breathing strategies to facilitate the extraction of adequate quantities of oxygen from their surrounding environments. Their respiratory structures can take a wide variety of forms, including integumentary surfaces, lungs, gills, tracheal systems, and even parallel combinations of these same gas exchange structures. Like their vertebrate counterparts, the invertebrates have evolved elaborate control strategies to regulate their breathing activity. Our goal in this article is to present the reader with a description of what is known regarding the control of breathing in some of the specific invertebrate species that have been used as model systems to study different mechanistic aspects of the control of breathing. We will examine how several species have been used to study fundamental principles of respiratory rhythm generation, central and peripheral chemosensory modulation of breathing, and plasticity in the control of breathing. We will also present the reader with an overview of some of the behavioral and neuronal adaptability that has been extensively documented in these animals. By presenting explicit invertebrate species as model organisms, we will illustrate mechanistic principles that form the neuronal foundation of respiratory control, and moreover appear likely to be conserved across not only invertebrates, but vertebrate species as well. PMID:23723022

  9. Generalized Reduced Order Modeling of Aeroservoelastic Systems

    NASA Astrophysics Data System (ADS)

    Gariffo, James Michael

    Transonic aeroelastic and aeroservoelastic (ASE) modeling presents a significant technical and computational challenge. Flow fields with a mixture of subsonic and supersonic flow, as well as moving shock waves, can only be captured through high-fidelity CFD analysis. With modern computing power, it is realtively straightforward to determine the flutter boundary for a single structural configuration at a single flight condition, but problems of larger scope remain quite costly. Some such problems include characterizing a vehicle's flutter boundary over its full flight envelope, optimizing its structural weight subject to aeroelastic constraints, and designing control laws for flutter suppression. For all of these applications, reduced-order models (ROMs) offer substantial computational savings. ROM techniques in general have existed for decades, and the methodology presented in this dissertation builds on successful previous techniques to create a powerful new scheme for modeling aeroelastic systems, and predicting and interpolating their transonic flutter boundaries. In this method, linear ASE state-space models are constructed from modal structural and actuator models coupled to state-space models of the linearized aerodynamic forces through feedback loops. Flutter predictions can be made from these models through simple eigenvalue analysis of their state-transition matrices for an appropriate set of dynamic pressures. Moreover, this analysis returns the frequency and damping trend of every aeroelastic branch. In contrast, determining the critical dynamic pressure by direct time-marching CFD requires a separate run for every dynamic pressure being analyzed simply to obtain the trend for the critical branch. The present ROM methodology also includes a new model interpolation technique that greatly enhances the benefits of these ROMs. This enables predictions of the dynamic behavior of the system for flight conditions where CFD analysis has not been explicitly

  10. Atmosphere - system analysis: models and data

    NASA Astrophysics Data System (ADS)

    Elbern, H.; Bittner, M.

    2003-04-01

    The presentation introduces an AFO2000 section with focus on earth observation issues in a broader sense. Satellite retrieval improvements, chemical data assimilation, humidity and cloud processes, as well as UT/LS chemistry are part of an activity, where the question is adressed how we can observe the earth's atmosphere to attain a picture as comprehensive as possible. With advanced algorithms the problem is adressed, to what extent processes, which are observed in nature, are understood by model simulations. A joint analysis is envisaged, i.e. all available information from measurements are to be combined with complex numerical models, so that a consistent picture of the atmosphere and its evolution is generated. Alternatively, in the case of discrepancies, we are able to identify significant deficiencies in our understanding of the system. In addition to numerical models, this approach requires computationally highly demanding algorithms. These are adopted from Inverse Modelling theory and allow for consistent analyses in an objective sense. Due to its continuous measurements, ENVISAT will play a central role by serving to confront chemistry transport models with data over long periods. Not all trace gases can by far be observed from space. However, under certain conditions, their distribution can be inferred by models in the framework of advanced space-time chemistry data assimilation methods, an inverse technique. Further assimilation efforts include global reconstruction of ozone profiles and of other constituents by numerical modelling and subsequent provision for scientific use. Archived data are also taken to extend the available time series. Efforts are undertaken to improve retrieval algorithms to infer concentration profiles directly from satellite data. Apart from satellite data remote sensing techniques in-situ-observations are also applied during field campaigns. An outstanding problem in atmospheric research, which requires such a combined use of

  11. Internal Dosimetry Code System Using Biokinetics Models

    2003-11-12

    Version 00 InDose is an internal dosimetry code to calculate dose estimations using biokinetic models (presented in ICRP-56 to ICRP71) as well as older ones. The code uses the ICRP-66 respiratory tract model and the ICRP-30 gastrointestinal tract model as well as the new and old biokinetic models. The code was written in such a way that the user can change any parameters of any one of the models without recompiling the code. All parametersmore » are given in well annotated parameters files that the user may change. As default, these files contain the values listed in ICRP publications. The full InDose code was planned to have three parts: 1) the main part includes the uptake and systemic models and is used to calculate the activities in the body tissues and excretion as a function of time for a given intake. 2) An optimization module for automatic estimation of the intake for a specific exposure case. 3) A module to calculate the dose due to the estimated intake. Currently, the code is able to perform only it`s main task (part 1) while the other two have to be done externally using other tools. In the future, developers would like to add these modules in order to provide a complete solution. The code was tested extensively to verify accuracy of its results. The verification procedure was divided into three parts: 1) verification of the implementation of each model, 2) verification of the integrity of the whole code, and 3) usability test. The first two parts consisted of comparing results obtained with InDose to published results for the same cases. For example ICRP-78 monitoring data. The last part consisted of participating in the 3rd EIE-IDA and assessing some of the scenarios provided in this exercise. These tests where presented in a few publications. Good agreement was found between the results of InDose and published data.« less

  12. On Mathematical Modeling Of Quantum Systems

    SciTech Connect

    Achuthan, P.; Narayanankutty, Karuppath

    2009-07-02

    The world of physical systems at the most fundamental levels is replete with efficient, interesting models possessing sufficient ability to represent the reality to a considerable extent. So far, quantum mechanics (QM) forming the basis of almost all natural phenomena, has found beyond doubt its intrinsic ingenuity, capacity and robustness to stand the rigorous tests of validity from and through appropriate calculations and experiments. No serious failures of quantum mechanical predictions have been reported, yet. However, Albert Einstein, the greatest theoretical physicist of the twentieth century and some other eminent men of science have stated firmly and categorically that QM, though successful by and large, is incomplete. There are classical and quantum reality models including those based on consciousness. Relativistic quantum theoretical approaches to clearly understand the ultimate nature of matter as well as radiation have still much to accomplish in order to qualify for a final theory of everything (TOE). Mathematical models of better, suitable character as also strength are needed to achieve satisfactory explanation of natural processes and phenomena. We, in this paper, discuss some of these matters with certain apt illustrations as well.

  13. Integrated modeling of advanced optical systems

    NASA Astrophysics Data System (ADS)

    Briggs, Hugh C.; Needels, Laura; Levine, B. Martin

    1993-02-01

    This poster session paper describes an integrated modeling and analysis capability being developed at JPL under funding provided by the JPL Director's Discretionary Fund and the JPL Control/Structure Interaction Program (CSI). The posters briefly summarize the program capabilities and illustrate them with an example problem. The computer programs developed under this effort will provide an unprecedented capability for integrated modeling and design of high performance optical spacecraft. The engineering disciplines supported include structural dynamics, controls, optics and thermodynamics. Such tools are needed in order to evaluate the end-to-end system performance of spacecraft such as OSI, POINTS, and SMMM. This paper illustrates the proof-of-concept tools that have been developed to establish the technology requirements and demonstrate the new features of integrated modeling and design. The current program also includes implementation of a prototype tool based upon the CAESY environment being developed under the NASA Guidance and Control Research and Technology Computational Controls Program. This prototype will be available late in FY-92. The development plan proposes a major software production effort to fabricate, deliver, support and maintain a national-class tool from FY-93 through FY-95.

  14. Logistics Modeling for Lunar Exploration Systems

    NASA Technical Reports Server (NTRS)

    Andraschko, Mark R.; Merrill, R. Gabe; Earle, Kevin D.

    2008-01-01

    The extensive logistics required to support extended crewed operations in space make effective modeling of logistics requirements and deployment critical to predicting the behavior of human lunar exploration systems. This paper discusses the software that has been developed as part of the Campaign Manifest Analysis Tool in support of strategic analysis activities under the Constellation Architecture Team - Lunar. The described logistics module enables definition of logistics requirements across multiple surface locations and allows for the transfer of logistics between those locations. A key feature of the module is the loading algorithm that is used to efficiently load logistics by type into carriers and then onto landers. Attention is given to the capabilities and limitations of this loading algorithm, particularly with regard to surface transfers. These capabilities are described within the context of the object-oriented software implementation, with details provided on the applicability of using this approach to model other human exploration scenarios. Some challenges of incorporating probabilistics into this type of logistics analysis model are discussed at a high level.

  15. Microgravity acceleration modeling for orbital systems

    NASA Technical Reports Server (NTRS)

    Knabe, Walter; Baugher, Charles R. (Editor)

    1990-01-01

    In view of the decisive importance of a disturbance-free environment on the Space Station, and on other orbital systems, for materials processing experiments, a theoretical and semi-experimental analysis of the acceleration environment to be expected on large orbiting spacecraft was undertaken. A unified model of such spacecraft cannot be established; therefore, a number of sub-models representing major components of typical large spacecraft must be investigated. In order to obtain experimental data of forces, a typical spacecraft - an engineering model of the Spacelab - was suspended on long ropes in a high-bay hangar, and equipped with a number of accelerometers. Active components on the Spacelab (fans, pumps, air conditioners, valves, levers) were operated, and astronautics moved boxes, drawers, sleds, and their own bodies. Generally speaking, the response of the Spacelab structure was very similar to the environment measured on Spacelabs SL-1, SL-2, and D-1. At frequencies in the broad range between 1 and about 100 Hz, acceleration peaks reached values of 10(exp -3) and 10(exp -2) g sub o, and even higher.

  16. On Mathematical Modeling Of Quantum Systems

    NASA Astrophysics Data System (ADS)

    Achuthan, P.; Narayanankutty, Karuppath

    2009-07-01

    The world of physical systems at the most fundamental levels is replete with efficient, interesting models possessing sufficient ability to represent the reality to a considerable extent. So far, quantum mechanics (QM) forming the basis of almost all natural phenomena, has found beyond doubt its intrinsic ingenuity, capacity and robustness to stand the rigorous tests of validity from and through appropriate calculations and experiments. No serious failures of quantum mechanical predictions have been reported, yet. However, Albert Einstein, the greatest theoretical physicist of the twentieth century and some other eminent men of science have stated firmly and categorically that QM, though successful by and large, is incomplete. There are classical and quantum reality models including those based on consciousness. Relativistic quantum theoretical approaches to clearly understand the ultimate nature of matter as well as radiation have still much to accomplish in order to qualify for a final theory of everything (TOE). Mathematical models of better, suitable character as also strength are needed to achieve satisfactory explanation of natural processes and phenomena. We, in this paper, discuss some of these matters with certain apt illustrations as well.

  17. A unifying framework for systems modeling, control systems design, and system operation

    NASA Technical Reports Server (NTRS)

    Dvorak, Daniel L.; Indictor, Mark B.; Ingham, Michel D.; Rasmussen, Robert D.; Stringfellow, Margaret V.

    2005-01-01

    Current engineering practice in the analysis and design of large-scale multi-disciplinary control systems is typified by some form of decomposition- whether functional or physical or discipline-based-that enables multiple teams to work in parallel and in relative isolation. Too often, the resulting system after integration is an awkward marriage of different control and data mechanisms with poor end-to-end accountability. System of systems engineering, which faces this problem on a large scale, cries out for a unifying framework to guide analysis, design, and operation. This paper describes such a framework based on a state-, model-, and goal-based architecture for semi-autonomous control systems that guides analysis and modeling, shapes control system software design, and directly specifies operational intent. This paper illustrates the key concepts in the context of a large-scale, concurrent, globally distributed system of systems: NASA's proposed Array-based Deep Space Network.

  18. The nu Andromedae System: Models and Stability

    NASA Technical Reports Server (NTRS)

    Stepinski, Tomasz F.; Malhotra, Renu; Black, David C.

    2000-01-01

    Radial velocity observations of the F8 V star nu Andromedae taken at Lick and at Whipple Observatories have revealed evidence of three periodicities in the line-of-sight velocity of the star. These periodicities have been interpreted as evidence for at least three low-mass companions (LMCs) revolving around nu Andromedae. The mass and orbital parameters inferred for these companions raise questions about the dynamical stability of the system. We report here results from our independent analysis of the published radial velocity data, as well as new unpublished data taken at Lick Observatory. Our results confirm the finding of three periods in the data. Our best fits to the data, on the assumption that these periods arise from the gravitational perturbations of companions in Keplerian orbits, are also generally in agreement but with some differences from the earlier findings. We find that the available data do not constrain well the orbital eccentricity of the middle companion in a three-companion model of the data. We also find that in order for our best-fit model to the Lick data to be dynamically stable over the lifetime of the star (approximately 2 billion years), the system must have a mean inclination to the plane of the sky greater than 13 deg. The corresponding minimum inclination for the best fit to the Whipple data set is 19 deg. These values imply that the maximum mass for the outer companion can be no greater than about 20 Jupiter masses. Our analysis of the stability of the putative systems also places constraints on the relative inclinations of the orbital planes of the companions. We comment on global versus local (i.e., method of steepest descent) means of finding best-fit orbits from radial velocity data sets.

  19. Kinetic modelling of heterogeneous catalytic systems

    NASA Astrophysics Data System (ADS)

    Stamatakis, Michail

    2015-01-01

    The importance of heterogeneous catalysis in modern life is evidenced by the fact that numerous products and technologies routinely used nowadays involve catalysts in their synthesis or function. The discovery of catalytic materials is, however, a non-trivial procedure, requiring tedious trial-and-error experimentation. First-principles-based kinetic modelling methods have recently emerged as a promising way to understand catalytic function and aid in materials discovery. In particular, kinetic Monte Carlo (KMC) simulation is increasingly becoming more popular, as it can integrate several sources of complexity encountered in catalytic systems, and has already been used to successfully unravel the underlying physics of several systems of interest. After a short discussion of the different scales involved in catalysis, we summarize the theory behind KMC simulation, and present the latest KMC computational implementations in the field. Early achievements that transformed the way we think about catalysts are subsequently reviewed in connection to latest studies of realistic systems, in an attempt to highlight how the field has evolved over the last few decades. Present challenges and future directions and opportunities in computational catalysis are finally discussed.

  20. System modeling speeds clamshell unloader delivery

    SciTech Connect

    Schuster, J.W.; Zirkler, A.H.; Duke, G.

    1995-04-01

    This article describes how enhanced dust control concepts and design studies found best method to ensure quick, safe clamshell unloader transport and assembly. A new facility, US Generating Co.`s Logan Generating Station, was built in New Jersey, along the Delaware River and four miles from Chester, Pa. At the outset, concerns arose over possible unusual regulatory issues because the plant`s coal barge unloading system extends into the river where it falls under the jurisdiction of the State of Delaware. However, the project contract with the equipment supplier avoided complications by calling for a turnkey project, including erection, start-up, commissioning and training. The supplier responded by using a modeling technique to ensure environmental compatibility. The contract called for one stationary-clamshell bucket grab unloader, complete with a dust control system, barge haul and barge breasting systems, and auxiliary cranes for handling the barge haul lines. Bucket coal capacity is 10 tons at 50 pounds per cubic foot density. When operating on a 40-second duty cycle, the unloader is rated at 910 tons per hour free digging capacity. Under dry, high dust conditions, the duty cycle is extended to 50 seconds to allow for pause time after the bucket closes and while over the hopper prior to bucket discharge.

  1. Application of Generic Disposal System Models

    SciTech Connect

    Mariner, Paul; Hammond, Glenn Edward; Sevougian, S. David; Stein, Emily

    2015-11-01

    This report describes specific GDSA activities in fiscal year 2015 (FY2015) toward the development of the enhanced disposal system modeling and analysis capability for geologic disposal of nuclear waste. The GDSA framework employs the PFLOTRAN thermal-hydrologic-chemical multi-physics code (Hammond et al., 2011) and the Dakota uncertainty sampling and propagation code (Adams et al., 2013). Each code is designed for massively-parallel processing in a high-performance computing (HPC) environment. Multi-physics representations in PFLOTRAN are used to simulate various coupled processes including heat flow, fluid flow, waste dissolution, radionuclide release, radionuclide decay and ingrowth, precipitation and dissolution of secondary phases, and radionuclide transport through the engineered barriers and natural geologic barriers to a well location in an overlying or underlying aquifer. Dakota is used to generate sets of representative realizations and to analyze parameter sensitivity.

  2. Model documentation report: Transportation sector model of the National Energy Modeling System

    SciTech Connect

    Not Available

    1994-03-01

    This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Transportation Model (TRAN). The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated by the model. This document serves three purposes. First, it is a reference document providing a detailed description of TRAN for model analysts, users, and the public. Second, this report meets the legal requirements of the Energy Information Administration (EIA) to provide adequate documentation in support of its statistical and forecast reports (Public Law 93-275, 57(b)(1)). Third, it permits continuity in model development by providing documentation from which energy analysts can undertake model enhancements, data updates, and parameter refinements.

  3. Overview of the GRC Stirling Convertor System Dynamic Model

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Regan, Timothy F.

    2004-01-01

    A Stirling Convertor System Dynamic Model has been developed at the Glenn Research Center for controls, dynamics, and systems development of free-piston convertor power systems. It models the Stirling cycle thermodynamics, heat flow, gas, mechanical, and mounting dynamics, the linear alternator, and the controller. The model's scope extends from the thermal energy input to thermal, mechanical dynamics, and electrical energy out, allowing one to study complex system interactions among subsystems. The model is a non-linear time-domain model containing sub-cycle dynamics, allowing it to simulate transient and dynamic phenomena that other models cannot. The model details and capability are discussed.

  4. Computer model of cardiovascular control system responses to exercise

    NASA Technical Reports Server (NTRS)

    Croston, R. C.; Rummel, J. A.; Kay, F. J.

    1973-01-01

    Approaches of systems analysis and mathematical modeling together with computer simulation techniques are applied to the cardiovascular system in order to simulate dynamic responses of the system to a range of exercise work loads. A block diagram of the circulatory model is presented, taking into account arterial segments, venous segments, arterio-venous circulation branches, and the heart. A cardiovascular control system model is also discussed together with model test results.

  5. Model documentation: Natural Gas Transmission and Distribution Model of the National Energy Modeling System; Volume 1

    SciTech Connect

    1994-02-24

    The Natural Gas Transmission and Distribution Model (NGTDM) is a component of the National Energy Modeling System (NEMS) used to represent the domestic natural gas transmission and distribution system. NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the Energy Information Administration (EIA) and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. This report documents the archived version of NGTDM that was used to produce the natural gas forecasts used in support of the Annual Energy Outlook 1994, DOE/EIA-0383(94). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic design, provides detail on the methodology employed, and describes the model inputs, outputs, and key assumptions. It is intended to fulfill the legal obligation of the EIA to provide adequate documentation in support of its models (Public Law 94-385, Section 57.b.2). This report represents Volume 1 of a two-volume set. (Volume 2 will report on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.) Subsequent chapters of this report provide: (1) an overview of the NGTDM (Chapter 2); (2) a description of the interface between the National Energy Modeling System (NEMS) and the NGTDM (Chapter 3); (3) an overview of the solution methodology of the NGTDM (Chapter 4); (4) the solution methodology for the Annual Flow Module (Chapter 5); (5) the solution methodology for the Distributor Tariff Module (Chapter 6); (6) the solution methodology for the Capacity Expansion Module (Chapter 7); (7) the solution methodology for the Pipeline Tariff Module (Chapter 8); and (8) a description of model assumptions, inputs, and outputs (Chapter 9).

  6. [Model-based biofuels system analysis: a review].

    PubMed

    Chang, Shiyan; Zhang, Xiliang; Zhao, Lili; Ou, Xunmin

    2011-03-01

    Model-based system analysis is an important tool for evaluating the potential and impacts of biofuels, and for drafting biofuels technology roadmaps and targets. The broad reach of the biofuels supply chain requires that biofuels system analyses span a range of disciplines, including agriculture/forestry, energy, economics, and the environment. Here we reviewed various models developed for or applied to modeling biofuels, and presented a critical analysis of Agriculture/Forestry System Models, Energy System Models, Integrated Assessment Models, Micro-level Cost, Energy and Emission Calculation Models, and Specific Macro-level Biofuel Models. We focused on the models' strengths, weaknesses, and applicability, facilitating the selection of a suitable type of model for specific issues. Such an analysis was a prerequisite for future biofuels system modeling, and represented a valuable resource for researchers and policy makers.

  7. Thoughts About Social Issues: A Neuman Systems Model Perspective.

    PubMed

    Aronowitz, Teri; Fawcett, Jacqueline

    2016-04-01

    The Neuman systems model includes social issues as a client system of interest. The other client systems of this conceptual model of nursing are individuals, families, other groups, and communities, about which exists a considerable amount of literature. However, social issues as a client system have not yet been defined or described, nor has any application of this client system been published. This essay is a discussion of the meaning of social issues as a client system from the perspective of the Neuman systems model, and offers examples from the literature, from the results of a survey of Neuman systems model trustees, including Betty Neuman, and from dialogue with participants at the 15th Biennial Neuman systems model symposium. This article was adapted from a paper presented at the 15(th) Biennial International Neuman Systems Model Symposium, Philadelphia, PA. June 19, 2015.

  8. A model for genesis of transcription systems.

    PubMed

    Burton, Zachary F; Opron, Kristopher; Wei, Guowei; Geiger, James H

    2016-01-01

    Repeating sequences generated from RNA gene fusions/ligations dominate ancient life, indicating central importance of building structural complexity in evolving biological systems. A simple and coherent story of life on earth is told from tracking repeating motifs that generate α/β proteins, 2-double-Ψ-β-barrel (DPBB) type RNA polymerases (RNAPs), general transcription factors (GTFs), and promoters. A general rule that emerges is that biological complexity that arises through generation of repeats is often bounded by solubility and closure (i.e., to form a pseudo-dimer or a barrel). Because the first DNA genomes were replicated by DNA template-dependent RNA synthesis followed by RNA template-dependent DNA synthesis via reverse transcriptase, the first DNA replication origins were initially 2-DPBB type RNAP promoters. A simplifying model for evolution of promoters/replication origins via repetition of core promoter elements is proposed. The model can explain why Pribnow boxes in bacterial transcription (i.e., (-12)TATAATG(-6)) so closely resemble TATA boxes (i.e., (-31)TATAAAAG(-24)) in archaeal/eukaryotic transcription. The evolution of anchor DNA sequences in bacterial (i.e., (-35)TTGACA(-30)) and archaeal (BRE(up); BRE for TFB recognition element) promoters is potentially explained. The evolution of BRE(down) elements of archaeal promoters is potentially explained.

  9. Modeling control systems for primary mirror supports

    NASA Astrophysics Data System (ADS)

    Fisher, Martin; Haque, Jaque; Wilkes, John D.; Amos, Clive S.; Steel, Darrin J.

    1995-06-01

    The RGO is involved in a number of mirror support programs, ranging from new controllers for its existing Isaac Newton Group (ING) telescopes to new primary mirror supports for the UK Infra-red Telescope (UKIRT) and design proposals for the active support of the Gemini 8 m meniscus mirrors. This work has led to the identification or development of critical components such as load cells and control valves which have high precision and stability. Even so it is still necessary to develop servo controllers capable of minimizing the effects of non- linearity and maintaining stability, particularly in regard to the highly non-linear behavior of pneumatic supports. In order to predict the performance of mirror supports and compare differing control strategies, components and systems are modelled using Matlab(superscript R) and Simulink(superscript R). These models are presented, together with parameters derived experimentally, and results from recent laboratory tests are discussed. Specific applications are described and current status of the work at the time of submission is presented.

  10. Sensitivity of system stability to model structure

    USGS Publications Warehouse

    Hosack, G.R.; Li, H.W.; Rossignol, P.A.

    2009-01-01

    A community is stable, and resilient, if the levels of all community variables can return to the original steady state following a perturbation. The stability properties of a community depend on its structure, which is the network of direct effects (interactions) among the variables within the community. These direct effects form feedback cycles (loops) that determine community stability. Although feedback cycles have an intuitive interpretation, identifying how they form the feedback properties of a particular community can be intractable. Furthermore, determining the role that any specific direct effect plays in the stability of a system is even more daunting. Such information, however, would identify important direct effects for targeted experimental and management manipulation even in complex communities for which quantitative information is lacking. We therefore provide a method that determines the sensitivity of community stability to model structure, and identifies the relative role of particular direct effects, indirect effects, and feedback cycles in determining stability. Structural sensitivities summarize the degree to which each direct effect contributes to stabilizing feedback or destabilizing feedback or both. Structural sensitivities prove useful in identifying ecologically important feedback cycles within the community structure and for detecting direct effects that have strong, or weak, influences on community stability. The approach may guide the development of management intervention and research design. We demonstrate its value with two theoretical models and two empirical examples of different levels of complexity. ?? 2009 Elsevier B.V. All rights reserved.

  11. Ice Sheet System Model as Educational Entertainment

    NASA Astrophysics Data System (ADS)

    Perez, G.

    2013-12-01

    Understanding the importance of polar ice sheets and their role in the evolution of Sea Level Rise (SLR), as well as Climate Change, is of paramount importance for policy makers as well as the public and schools at large. For example, polar ice sheets and glaciers currently account for 1/3 of the SLR signal, a ratio that will increase in the near to long-term future, which has tremendous societal ramifications. Consequently, it is important to increase awareness about our changing planet. In our increasingly digital society, mobile and web applications are burgeoning venues for such outreach. The Ice Sheet System Model (ISSM) is a software that was developed at the Jet Propulsion Laboratory/CalTech/NASA, in collaboration with University of California Irvine (UCI), with the goal of better understanding the evolution of polar ice sheets. It is a state-of-the-art framework, which relies on higher-end cluster-computing to address some of the aforementioned challenges. In addition, it is a flexible framework that can be deployed on any hardware; in particular, on mobile platforms such as Android or iOS smart phones. Here, we look at how the ISSM development team managed to port their model to these platforms, what the implications are for improving how scientists disseminate their results, and how a broader audience may familiarize themselves with running complex climate models in simplified scenarios which are highly educational and entertaining in content. We also look at the future plans toward a web portal fully integrated with mobile technologies to deliver the best content to the public, and to provide educational plans/lessons that can be used in grades K-12 as well as collegiate under-graduate and graduate programs.

  12. Expert Systems as a Mindtool To Facilitate Mental Model Learning.

    ERIC Educational Resources Information Center

    Mason-Mason, Susan Dale; Tessmer, Martin A.

    2000-01-01

    This exploratory study investigated whether the process of constructing an expert system model promotes the formation of expert-like mental models. Discusses expert systems as mindtools, expert systems as learning tools, the assessment of mental models, results of pretests and posttests, and future research. (Contains 56 references.) (Author/LRW)

  13. Digital Avionics Information System (DAIS): Training Requirements Analysis Model (TRAMOD).

    ERIC Educational Resources Information Center

    Czuchry, Andrew J.; And Others

    The training requirements analysis model (TRAMOD) described in this report represents an important portion of the larger effort called the Digital Avionics Information System (DAIS) Life Cycle Cost (LCC) Study. TRAMOD is the second of three models that comprise an LCC impact modeling system for use in the early stages of system development. As…

  14. Systems modeling at the Idaho National Engineering Laboratory

    NASA Astrophysics Data System (ADS)

    Bray, Michael A.

    1994-12-01

    This paper describes two experiences in systems modeling at the Idaho National Engineering Laboratory. These experiences reinforce key points that bear on the use of systems modeling in analyzing health-care issues. The first point is that mental models are a crucial part of systems. The second point is that simulation uncovers long-term consequences of existing assumptions.

  15. Parametric modelling for electrical impedance spectroscopy system.

    PubMed

    Lu, L; Hamzaoui, L; Brown, B H; Rigaud, B; Smallwood, R H; Barber, D C; Morucci, J P

    1996-03-01

    Three parametric modelling approaches based on the Cole-Cole model are introduced. Comparison between modelling only the real part and modelling both the real and imaginary parts is carried out by simulations, in which random and systematic noise are considered, respectively. The results of modelling the in vitro data collected from sheep are given to reach the conclusions.

  16. Combustion system CFD modeling at GE Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Burrus, D.; Mongia, H.; Tolpadi, Anil K.; Correa, S.; Braaten, M.

    1995-01-01

    This viewgraph presentation discusses key features of current combustion system CFD modeling capabilities at GE Aircraft Engines provided by the CONCERT code; CONCERT development history; modeling applied for designing engine combustion systems; modeling applied to improve fundamental understanding; CONCERT3D results for current production combustors; CONCERT3D model of NASA/GE E3 combustor; HYBRID CONCERT CFD/Monte-Carlo modeling approach; and future modeling directions.

  17. Model documentation Natural Gas Transmission and Distribution Model of the National Energy Modeling System. Volume 1

    SciTech Connect

    1996-02-26

    The Natural Gas Transmission and Distribution Model (NGTDM) of the National Energy Modeling System is developed and maintained by the Energy Information Administration (EIA), Office of Integrated Analysis and Forecasting. This report documents the archived version of the NGTDM that was used to produce the natural gas forecasts presented in the Annual Energy Outlook 1996, (DOE/EIA-0383(96)). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic approach, and provides detail on the methodology employed. Previously this report represented Volume I of a two-volume set. Volume II reported on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.

  18. Aligning Goal and Value Models for Information System Design

    NASA Astrophysics Data System (ADS)

    Edirisuriya, Ananda; Zdravkovic, Jelena

    The success of process-aware information systems and web services heavily depends on their ability to work as catalysts for the business values that are being exchanged in a business model. The motivation of a business model can be found in the goals of an enterprise which are made explicit in a goal model. From the IT perspective, goal and business models form part of a chain of models, ending with an information system model. Thereby, analyzing and establishing the alignment of business models with goal models is a starting task on the way to a business-aware information system. This paper discusses the alignment of value-based business models with system-oriented goal models. The result is a set of transformation rules between the two models. A case study from the health sector is used to argument the way we ground and apply our contribution.

  19. A logical model of cooperating rule-based systems

    NASA Technical Reports Server (NTRS)

    Bailin, Sidney C.; Moore, John M.; Hilberg, Robert H.; Murphy, Elizabeth D.; Bahder, Shari A.

    1989-01-01

    A model is developed to assist in the planning, specification, development, and verification of space information systems involving distributed rule-based systems. The model is based on an analysis of possible uses of rule-based systems in control centers. This analysis is summarized as a data-flow model for a hypothetical intelligent control center. From this data-flow model, the logical model of cooperating rule-based systems is extracted. This model consists of four layers of increasing capability: (1) communicating agents, (2) belief-sharing knowledge sources, (3) goal-sharing interest areas, and (4) task-sharing job roles.

  20. Modeling of Electrocardiograph Telediagnosing System Based on Petri Net

    NASA Astrophysics Data System (ADS)

    Hu, Wensong; Li, Ming; Li, Lan

    This paper analyzed the characteristics of the electrocardiograph telediagnosing system. Firstly, we introduce the system and Petri nets. Secondly, we built a topological diagram of this system. Then we use Petri nets to show the physical process of this system. Finally, we verified the model of the electrocardiograph telediagnosing system. With the help of model based on Petri nets, we analyzed the system performance and feasibility.

  1. Modeling Reactor Coolant Systems Thermal-Hydraulic Transients

    1999-10-05

    RELAP5/MOD3.2* is used to model reactor coolant systems during postulated accidents. The code models the coupled behavior of the reactor coolant system and the core for loss-of-coolant accidents and operational transients such as anticipated transients without scram, loss of offsite power, loss of feedwater, and loss of flow. A generic modeling approach is used that permits simulating a variety of thermal-hydraulic systems. Control system and secondary system components are included to allow modeling of themore » plant controls, turbines, condensers, and secondary feedwater systems.« less

  2. Systems and context modeling approach to requirements analysis

    NASA Astrophysics Data System (ADS)

    Ahuja, Amrit; Muralikrishna, G.; Patwari, Puneet; Subhrojyoti, C.; Swaminathan, N.; Vin, Harrick

    2014-08-01

    Ensuring completeness and correctness of the requirements for a complex system such as the SKA is challenging. Current system engineering practice includes developing a stakeholder needs definition, a concept of operations, and defining system requirements in terms of use cases and requirements statements. We present a method that enhances this current practice into a collection of system models with mutual consistency relationships. These include stakeholder goals, needs definition and system-of-interest models, together with a context model that participates in the consistency relationships among these models. We illustrate this approach by using it to analyze the SKA system requirements.

  3. A Living-Systems Design Model for Web-based Knowledge Management Systems.

    ERIC Educational Resources Information Center

    Plass, Jan L.; Salisbury, Mark W.

    2002-01-01

    Reviews currently available instructional systems design models and describes a new design model for Web-based knowledge management (KM) systems, based on a living-systems approach, and the mechanisms it contains for accommodating change and growth. Illustrates the application of the phases of the model in the development of a KM system with…

  4. Systems Modeling to Implement Integrated System Health Management Capability

    NASA Technical Reports Server (NTRS)

    Figueroa, Jorge F.; Walker, Mark; Morris, Jonathan; Smith, Harvey; Schmalzel, John

    2007-01-01

    ISHM capability includes: detection of anomalies, diagnosis of causes of anomalies, prediction of future anomalies, and user interfaces that enable integrated awareness (past, present, and future) by users. This is achieved by focused management of data, information and knowledge (DIaK) that will likely be distributed across networks. Management of DIaK implies storage, sharing (timely availability), maintaining, evolving, and processing. Processing of DIaK encapsulates strategies, methodologies, algorithms, etc. focused on achieving high ISHM Functional Capability Level (FCL). High FCL means a high degree of success in detecting anomalies, diagnosing causes, predicting future anomalies, and enabling health integrated awareness by the user. A model that enables ISHM capability, and hence, DIaK management, is denominated the ISHM Model of the System (IMS). We describe aspects of the IMS that focus on processing of DIaK. Strategies, methodologies, and algorithms require proper context. We describe an approach to define and use contexts, implementation in an object-oriented software environment (G2), and validation using actual test data from a methane thruster test program at NASA SSC. Context is linked to existence of relationships among elements of a system. For example, the context to use a strategy to detect leak is to identify closed subsystems (e.g. bounded by closed valves and by tanks) that include pressure sensors, and check if the pressure is changing. We call these subsystems Pressurizable Subsystems. If pressure changes are detected, then all members of the closed subsystem become suspect of leakage. In this case, the context is defined by identifying a subsystem that is suitable for applying a strategy. Contexts are defined in many ways. Often, a context is defined by relationships of function (e.g. liquid flow, maintaining pressure, etc.), form (e.g. part of the same component, connected to other components, etc.), or space (e.g. physically close

  5. Investigating System Dependability Modeling Using AADL

    NASA Technical Reports Server (NTRS)

    Hall, Brendan; Driscoll, Kevin R.; Madl, Gabor

    2013-01-01

    This report describes Architecture Analysis & Design Language (AADL) models for a diverse set of fault-tolerant, embedded data networks and describes the methods and tools used to created these models. It also includes error models per the AADL Error Annex. Some networks were modeled using Error Detection Isolation Containment Types (EDICT). This report gives a brief description for each of the networks, a description of its modeling, the model itself, and evaluations of the tools used for creating the models. The methodology includes a naming convention that supports a systematic way to enumerate all of the potential failure modes.

  6. Modeling an ancient Iranian dam system

    NASA Astrophysics Data System (ADS)

    Ertsen, Maurits; De Schacht, Tijs

    2013-04-01

    In Iran, along the northern and eastern fringes of the Pasargadae plain, five dam remains from the Achaemenid period (550-330 BCE) present an important footprint of the human impact and reshaping of the region. The dams are predominantly found in dry wadi beds. In the framework of the Joint Iranian-French Archaeological Project at Pasargadae, these dam sites were studied and excavated. Located 22 km to the north of Pasargadae in a small wadi, the Sad-i Didegan dam has a watershed of circa 46 square km, small compared with catchments of other known Achaemenid dams. It is an earth built gravity dam of circa 90 m wide, 21 m high and with a crown length of about 150 m. In the lower body of the dam, remains of a feeder canal and an accessible control infrastructure at the downstream flank of the dam were found. To the northwest, the dam site of Sad-i Shahidabad can be found, another large Achaemenid dam, which stored water from the perennial river of the Rud-i Polvar. This dam also had a similar canal and control structure. Close to the Sad-i Didegan area is a large earthwork, found to cross the watershed divide between Didegan and Shahidabad, consisting of a wide V-shaped trench of remarkable size: up to 100 m wide, a total length of at least 900 m and a maximum present day depth of 7.5 m. Even though the construction of the system in this case clearly was left unfinished, the remains echo the major investment of available labor. Given the contemporaneity of both dam sites, it is clear evidence of the more regionally and elaborately planned character of the hydrological endeavors in the Pasargadae area. Only through further study and future fieldwork (also obtaining absolute dating material), this impressive feature will be fully understood. This contribution proposes a possible use of the two dam system using a modern control simulation model. This analysis will also shed light on the question why the system probably never functioned.

  7. A Dynamic Systems Model of Cognitive and Language Growth.

    ERIC Educational Resources Information Center

    van Geert, Paul

    1991-01-01

    A conceptual framework of cognitive growth is sketched and a mathematical model of cognitive growth is presented with the conclusion that the most plausible model is a model of logistic growth with delayed feedback. The model is transformed into a dynamic systems model based on the logistic-growth equation. (SLD)

  8. Optimized Markov state models for metastable systems

    NASA Astrophysics Data System (ADS)

    Guarnera, Enrico; Vanden-Eijnden, Eric

    2016-07-01

    A method is proposed to identify target states that optimize a metastability index amongst a set of trial states and use these target states as milestones (or core sets) to build Markov State Models (MSMs). If the optimized metastability index is small, this automatically guarantees the accuracy of the MSM, in the sense that the transitions between the target milestones is indeed approximately Markovian. The method is simple to implement and use, it does not require that the dynamics on the trial milestones be Markovian, and it also offers the possibility to partition the system's state-space by assigning every trial milestone to the target milestones it is most likely to visit next and to identify transition state regions. Here the method is tested on the Gly-Ala-Gly peptide, where it is shown to correctly identify the expected metastable states in the dihedral angle space of the molecule without a priori information about these states. It is also applied to analyze the folding landscape of the Beta3s mini-protein, where it is shown to identify the folded basin as a connecting hub between an helix-rich region, which is entropically stabilized, and a beta-rich region, which is energetically stabilized and acts as a kinetic trap.

  9. Flavor release measurement from gum model system.

    PubMed

    Ovejero-López, Isabel; Haahr, Anne-Mette; van den Berg, Frans; Bredie, Wender L P

    2004-12-29

    Flavor release from a mint-flavored chewing gum model system was measured by atmospheric pressure chemical ionization mass spectroscopy (APCI-MS) and sensory time-intensity (TI). A data analysis method for handling the individual curves from both methods is presented. The APCI-MS data are ratio-scaled using the signal from acetone in the breath of subjects. Next, APCI-MS and sensory TI curves are smoothed by low-pass filtering. Principal component analysis of the individual curves is used to display graphically the product differentiation by APCI-MS or TI signals. It is shown that differences in gum composition can be measured by both instrumental and sensory techniques, providing comparable information. The peppermint oil level (0.5-2% w/w) in the gum influenced both the retronasal concentration and the perceived peppermint flavor. The sweeteners' (sorbitol or xylitol) effect is less apparent. Sensory adaptation and sensitivity differences of human perception versus APCI-MS detection might explain the divergence between the two dynamic measurement methods. PMID:15612805

  10. Model of the Ares V Launch System

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This is a studio photograph of a model of the Ares V rocket. Named for the Greek god associated with Mars, Ares vehicles will return humans to the moon and later take them to Mars and other destinations. The Ares V is a heavy lift launch vehicle that will use five RS-68 liquid oxygen/liquid hydrogen engines mounted below a larger version of the space shuttle external tank, and two five-segment solid propellant rocket boosters for the first stage. The upper stage will use the same J-2X engine as the Ares I. The Ares V can lift more than 286,000 pounds to low Earth orbit and stands approximately 360 feet tall. This versatile system will be used to carry cargo and the components into orbit needed to go to the moon and later to Mars, while the Crew will be carried by the Ares I. Ares V is subject to configuration changes before it is actually launched. This illustration reflects the latest configuration as of September 2006.

  11. Spatiotemporal stochastic resonance and its consequences in neural model systems.

    PubMed

    Balazsi, Gabor; Kish, Laszlo B.; Moss, Frank E.

    2001-09-01

    The realization of spatiotemporal stochastic resonance is studied in a two-dimensional FitzHugh-Nagumo system, and in a one-dimensional system of integrate-and-fire neurons. We show that spatiotemporal stochastic resonance occurs in these neural model systems, independent of the method of modeling. Moreover, the ways of realization are analogous in the two model systems. The biological implications and open questions are discussed. (c) 2001 American Institute of Physics. PMID:12779493

  12. Linear programming model for optimum resource allocation in rural systems

    SciTech Connect

    Devadas, V.

    1997-07-01

    The article presents a model for optimum resource allocation in a rural system. Making use of linear programming, the objective function of the linear programming model is to maximize the revenue of the rural system, and optimum resource allocation is made subject to a number of energy- and nonenergy-related constraints relevant to the rural system. The model also quantifies the major yields as well as the by-products of different sectors of the rural economic system.

  13. The UC-LLNL Regional Climate System Model

    SciTech Connect

    Miller, N.L.; Kim, Jinwon

    1996-09-01

    The UC-LLNL Regional Climate System Model has been under development since 1991. The unique system simulates climate from the global scale down to the watershed catchment scale, and consists of data pre- and post- processors, and four model components. The four model components are (1) a mesoscale atmospheric simulation model, (2) a soil-plant-snow model, (3) a watershed hydrology-riverflow model, and (4) a suite of crop response models. The first three model components have been coupled, and the system includes two-way feedbacks between the soil-plant-snow model and the mesoscale atmospheric simulation model. This three-component version of RCSM has been tested, validated, and successfully used for operational quantitative precipitation forecasts and seasonal water resource studies over the southwestern US. We are currently implementation and validating the fourth component, the Decision Support system for Agrotechnology Transfer (DSSAT). A description of the UC-LLNL RCSM and some recent results are presented.

  14. Enhancing Systems-Thinking Skills with Modelling

    ERIC Educational Resources Information Center

    Hung, Woei

    2008-01-01

    Systems thinking is an essential cognitive skill that enables individuals to develop an integrative understanding of a given subject at the conceptual and systemic level. Yet, systems thinking is not usually an innate skill. Helping students develop systems-thinking skills warrants attention from educators. This paper describes a study examining…

  15. Modeling of batch sorber system: kinetic, mechanistic, and thermodynamic modeling

    NASA Astrophysics Data System (ADS)

    Mishra, Vishal

    2016-09-01

    The present investigation has dealt with the biosorption of copper and zinc ions on the surface of egg-shell particles in the liquid phase. Various rate models were evaluated to elucidate the kinetics of copper and zinc biosorptions, and the results indicated that the pseudo-second-order model was more appropriate than the pseudo-first-order model. The curve of the initial sorption rate versus the initial concentration of copper and zinc ions also complemented the results of the pseudo-second-order model. Models used for the mechanistic modeling were the intra-particle model of pore diffusion and Bangham's model of film diffusion. The results of the mechanistic modeling together with the values of pore and film diffusivities indicated that the preferential mode of the biosorption of copper and zinc ions on the surface of egg-shell particles in the liquid phase was film diffusion. The results of the intra-particle model showed that the biosorption of the copper and zinc ions was not dominated by the pore diffusion, which was due to macro-pores with open-void spaces present on the surface of egg-shell particles. The thermodynamic modeling reproduced the fact that the sorption of copper and zinc was spontaneous, exothermic with the increased order of the randomness at the solid-liquid interface.

  16. A Model-Driven Visualization Tool for Use with Model-Based Systems Engineering Projects

    NASA Technical Reports Server (NTRS)

    Trase, Kathryn; Fink, Eric

    2014-01-01

    Model-Based Systems Engineering (MBSE) promotes increased consistency between a system's design and its design documentation through the use of an object-oriented system model. The creation of this system model facilitates data presentation by providing a mechanism from which information can be extracted by automated manipulation of model content. Existing MBSE tools enable model creation, but are often too complex for the unfamiliar model viewer to easily use. These tools do not yet provide many opportunities for easing into the development and use of a system model when system design documentation already exists. This study creates a Systems Modeling Language (SysML) Document Traceability Framework (SDTF) for integrating design documentation with a system model, and develops an Interactive Visualization Engine for SysML Tools (InVEST), that exports consistent, clear, and concise views of SysML model data. These exported views are each meaningful to a variety of project stakeholders with differing subjects of concern and depth of technical involvement. InVEST allows a model user to generate multiple views and reports from a MBSE model, including wiki pages and interactive visualizations of data. System data can also be filtered to present only the information relevant to the particular stakeholder, resulting in a view that is both consistent with the larger system model and other model views. Viewing the relationships between system artifacts and documentation, and filtering through data to see specialized views improves the value of the system as a whole, as data becomes information

  17. A dynamic fault tree model of a propulsion system

    NASA Technical Reports Server (NTRS)

    Xu, Hong; Dugan, Joanne Bechta; Meshkat, Leila

    2006-01-01

    We present a dynamic fault tree model of the benchmark propulsion system, and solve it using Galileo. Dynamic fault trees (DFT) extend traditional static fault trees with special gates to model spares and other sequence dependencies. Galileo solves DFT models using a judicious combination of automatically generated Markov and Binary Decision Diagram models. Galileo easily handles the complexities exhibited by the benchmark problem. In particular, Galileo is designed to model phased mission systems.

  18. Optimization of large-scale heterogeneous system-of-systems models.

    SciTech Connect

    Parekh, Ojas; Watson, Jean-Paul; Phillips, Cynthia Ann; Siirola, John; Swiler, Laura Painton; Hough, Patricia Diane; Lee, Herbert K. H.; Hart, William Eugene; Gray, Genetha Anne; Woodruff, David L.

    2012-01-01

    Decision makers increasingly rely on large-scale computational models to simulate and analyze complex man-made systems. For example, computational models of national infrastructures are being used to inform government policy, assess economic and national security risks, evaluate infrastructure interdependencies, and plan for the growth and evolution of infrastructure capabilities. A major challenge for decision makers is the analysis of national-scale models that are composed of interacting systems: effective integration of system models is difficult, there are many parameters to analyze in these systems, and fundamental modeling uncertainties complicate analysis. This project is developing optimization methods to effectively represent and analyze large-scale heterogeneous system of systems (HSoS) models, which have emerged as a promising approach for describing such complex man-made systems. These optimization methods enable decision makers to predict future system behavior, manage system risk, assess tradeoffs between system criteria, and identify critical modeling uncertainties.

  19. Advanced Ground Systems Maintenance Physics Models for Diagnostics Project

    NASA Technical Reports Server (NTRS)

    Harp, Janicce Leshay

    2014-01-01

    The project will use high-fidelity physics models and simulations to simulate real-time operations of cryogenic and systems and calculate the status/health of the systems. The project enables the delivery of system health advisories to ground system operators. The capability will also be used to conduct planning and analysis of cryogenic system operations.

  20. NDA SYSTEM RESPONSE MODELING AND ITS APPLICATION

    SciTech Connect

    Vinson, D.

    2010-03-01

    is of the form of uranyl fluoride that will become hydrated on exposure to moisture in air when the systems are no longer buffered. The deposit geometry and thickness is uncertain and variable. However, a reasonable assessment of the level of material holdup in this equipment is necessary to support decommissioning efforts. The assessment of nuclear material holdup in process equipment is a complex process that requires integration of process knowledge, nondestructive assay (NDA) measurements, and computer modeling to maximize capabilities and minimize uncertainty. The current report is focused on the use of computer modeling and simulation of NDA measurements.

  1. Neural fuzzy modeling of anaerobic biological wastewater treatment systems

    SciTech Connect

    Tay, J.H.; Zhang, X.

    1999-12-01

    Anaerobic biological wastewater treatment systems are difficult to model because their performance is complex and varies significantly with different reactor configurations, influent characteristics, and operational conditions. Instead of conventional kinetic modeling, advanced neural fuzzy technology was employed to develop a conceptual adaptive model for anaerobic treatment systems. The conceptual neural fuzzy model contains the robustness of fuzzy systems, the learning ability of neural networks, and can adapt to various situations. The conceptual model was used to simulate the daily performance of two high-rate anaerobic wastewater treatment systems with satisfactory results obtained.

  2. A hierarchy for modeling high speed propulsion systems

    NASA Technical Reports Server (NTRS)

    Hartley, Tom T.; Deabreu, Alex

    1991-01-01

    General research efforts on reduced order propulsion models for control systems design are overviewed. Methods for modeling high speed propulsion systems are discussed including internal flow propulsion systems that do not contain rotating machinery such as inlets, ramjets, and scramjets. The discussion is separated into four sections: (1) computational fluid dynamics model for the entire nonlinear system or high order nonlinear models; (2) high order linearized model derived from fundamental physics; (3) low order linear models obtained from other high order models; and (4) low order nonlinear models. Included are special considerations on any relevant control system designs. The methods discussed are for the quasi-one dimensional Euler equations of gasdynamic flow. The essential nonlinear features represented are large amplitude nonlinear waves, moving normal shocks, hammershocks, subsonic combustion via heat addition, temperature dependent gases, detonation, and thermal choking.

  3. Molybdenum Enzymes, Cofactors, and Model Systems.

    ERIC Educational Resources Information Center

    Burgmayer, S. J. N; Stiefel, E. I.

    1985-01-01

    Discusses: (l) molybdoenzymes (examining their distribution and metabolic role, composition and redox strategy, cofactors, substrate reactions, and mechanistic possibilities); (2) structural information on molybdenum (Mo) centers; (3) modeling studies (Mo-co models, nitrogenase models, and the MO-S duo); and (4) the copper-molybdenum antagonism.…

  4. Tutorial: Mathematical Modeling of Library Systems.

    ERIC Educational Resources Information Center

    Rouse, William B.

    1979-01-01

    Discusses the purpose of mathematical models and reviews the phases of the modeling process--defining performance, representing the problem, predicting performance, estimating parameters, defining optimization criterion, determining solution, and implementing results. Reviews of book-use, resource allocation, and library network models are…

  5. Modeling of the silane FBR system

    NASA Technical Reports Server (NTRS)

    Dudokovic, M. P.; Ramachandran, P. A.; Lai, S.

    1984-01-01

    Development of a mathematical model for fluidized bed pyrolysis of silane that relates production rate and product properties (size, size distribution, presence or absence of fines) with bed size and operating conditions (temperature, feed concentration, flow rate, seed size, etc.) and development of user oriented algorithm for the model are considered. A parameter sensitivity study of the model was also developed.

  6. Propagation modeling for land mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Barts, R. Michael; Stutzman, Warren L.

    1988-01-01

    A simplified empirical model for predicting primary fade statistics for a vegetatively shadowed mobile satellite signal is presented, and predictions based on the model are presented using propagation parameter values from experimental data. Results from the empirical model are used to drive a propagation simulator to produce the secondary fade statistics of average fade duration.

  7. Workshop Introduction: Systems Biology and Biological Models

    EPA Science Inventory

    As we consider the future of toxicity testing, the importance of applying biological models to this problem is clear. Modeling efforts exist along a continuum with respect to the level of organization (e.g. cell, tissue, organism) linked to the resolution of the model. Generally,...

  8. Applications of SPICE for modeling miniaturized biomedical sensor systems

    NASA Technical Reports Server (NTRS)

    Mundt, C. W.; Nagle, H. T.

    2000-01-01

    This paper proposes a model for a miniaturized signal conditioning system for biopotential and ion-selective electrode arrays. The system consists of three main components: sensors, interconnections, and signal conditioning chip. The model for this system is based on SPICE. Transmission-line based equivalent circuits are used to represent the sensors, lumped resistance-capacitance circuits describe the interconnections, and a model for the signal conditioning chip is extracted from its layout. A system for measurements of biopotentials and ionic activities can be miniaturized and optimized for cardiovascular applications based on the development of an integrated SPICE system model of its electrochemical, interconnection, and electronic components.

  9. Modeling the Delivery Physiology of Distributed Learning Systems.

    ERIC Educational Resources Information Center

    Paquette, Gilbert; Rosca, Ioan

    2003-01-01

    Discusses instructional delivery models and their physiology in distributed learning systems. Highlights include building delivery models; types of delivery models, including distributed classroom, self-training on the Web, online training, communities of practice, and performance support systems; and actors (users) involved, including experts,…

  10. Analysis Model for Domestic Hot Water Distribution Systems: Preprint

    SciTech Connect

    Maguire, J.; Krarti, M.; Fang, X.

    2011-11-01

    A thermal model was developed to estimate the energy losses from prototypical domestic hot water (DHW) distribution systems for homes. The developed model, using the TRNSYS simulation software, allows researchers and designers to better evaluate the performance of hot water distribution systems in homes. Modeling results were compared with past experimental study results and showed good agreement.

  11. Rhode Island Model Evaluation & Support System: Teacher. Edition III

    ERIC Educational Resources Information Center

    Rhode Island Department of Education, 2015

    2015-01-01

    Rhode Island educators believe that implementing a fair, accurate, and meaningful educator evaluation and support system will help improve teaching and learning. The primary purpose of the Rhode Island Model Teacher Evaluation and Support System (Rhode Island Model) is to help all teachers improve. Through the Model, the goal is to help create a…

  12. Computer Integrated Manufacturing: Physical Modelling Systems Design. A Personal View.

    ERIC Educational Resources Information Center

    Baker, Richard

    A computer-integrated manufacturing (CIM) Physical Modeling Systems Design project was undertaken in a time of rapid change in the industrial, business, technological, training, and educational areas in Australia. A specification of a manufacturing physical modeling system was drawn up. Physical modeling provides a flexibility and configurability…

  13. Petroleum Market Model of the National Energy Modeling System

    SciTech Connect

    1997-01-01

    The purpose of this report is to define the objectives of the Petroleum Market Model (PMM), describe its basic approach, and provide detail on how it works. This report is intended as a reference document for model analysts, users, and the public. The PMM models petroleum refining activities, the marketing of petroleum products to consumption regions. The production of natural gas liquids in gas processing plants, and domestic methanol production. The PMM projects petroleum product prices and sources of supply for meeting petroleum product demand. The sources of supply include crude oil, both domestic and imported; other inputs including alcohols and ethers; natural gas plant liquids production; petroleum product imports; and refinery processing gain. In addition, the PMM estimates domestic refinery capacity expansion and fuel consumption. Product prices are estimated at the Census division level and much of the refining activity information is at the Petroleum Administration for Defense (PAD) District level. This report is organized as follows: Chapter 2, Model Purpose; Chapter 3, Model Overview and Rationale; Chapter 4, Model Structure; Appendix A, Inventory of Input Data, Parameter Estimates, and Model Outputs; Appendix B, Detailed Mathematical Description of the Model; Appendix C, Bibliography; Appendix D, Model Abstract; Appendix E, Data Quality; Appendix F, Estimation methodologies; Appendix G, Matrix Generator documentation; Appendix H, Historical Data Processing; and Appendix I, Biofuels Supply Submodule.

  14. Agent-based modeling and systems dynamics model reproduction.

    SciTech Connect

    North, M. J.; Macal, C. M.

    2009-01-01

    Reproducibility is a pillar of the scientific endeavour. We view computer simulations as laboratories for electronic experimentation and therefore as tools for science. Recent studies have addressed model reproduction and found it to be surprisingly difficult to replicate published findings. There have been enough failed simulation replications to raise the question, 'can computer models be fully replicated?' This paper answers in the affirmative by reporting on a successful reproduction study using Mathematica, Repast and Swarm for the Beer Game supply chain model. The reproduction process was valuable because it demonstrated the original result's robustness across modelling methodologies and implementation environments.

  15. The semiotics of control and modeling relations in complex systems.

    PubMed

    Joslyn, C

    2001-01-01

    We provide a conceptual analysis of ideas and principles from the systems theory discourse which underlie Pattee's semantic or semiotic closure, which is itself foundational for a school of theoretical biology derived from systems theory and cybernetics, and is now being related to biological semiotics and explicated in the relational biological school of Rashevsky and Rosen. Atomic control systems and models are described as the canonical forms of semiotic organization, sharing measurement relations, but differing topologically in that control systems are circularly and models linearly related to their environments. Computation in control systems is introduced, motivating hierarchical decomposition, hybrid modeling and control systems, and anticipatory or model-based control. The semiotic relations in complex control systems are described in terms of relational constraints, and rules and laws are distinguished as contingent and necessary functional entailments, respectively. Finally, selection as a meta-level of constraint is introduced as the necessary condition for semantic relations in control systems and models.

  16. The Community Climate System Model Version 4

    SciTech Connect

    Gent, Peter R.; Danabasoglu, Gokhan; Donner, Leo J.; Holland, Marika M.; Hunke, Elizabeth C.; Jayne, Steve R.; Lawrence, David M.; Neale, Richard; Rasch, Philip J.; Vertenstein, Mariana; Worley, Patrick; Yang, Zong-Liang; Zhang, Minghua

    2011-10-01

    The fourth version of the Community Climate System Model (CCSM4) was recently completed and released to the climate community. This paper describes developments to all the CCSM components, and documents fully coupled pre-industrial control runs compared to the previous version, CCSM3. Using the standard atmosphere and land resolution of 1{sup o} results in the sea surface temperature biases in the major upwelling regions being comparable to the 1.4{sup o} resolution CCSM3. Two changes to the deep convection scheme in the atmosphere component result in the CCSM4 producing El Nino/Southern Oscillation variability with a much more realistic frequency distribution than the CCSM3, although the amplitude is too large compared to observations. They also improve the representation of the Madden-Julian Oscillation, and the frequency distribution of tropical precipitation. A new overflow parameterization in the ocean component leads to an improved simulation of the deep ocean density structure, especially in the North Atlantic. Changes to the CCSM4 land component lead to a much improved annual cycle of water storage, especially in the tropics. The CCSM4 sea ice component uses much more realistic albedos than the CCSM3, and the Arctic sea ice concentration is improved in the CCSM4. An ensemble of 20th century simulations runs produce an excellent match to the observed September Arctic sea ice extent from 1979 to 2005. The CCSM4 ensemble mean increase in globally-averaged surface temperature between 1850 and 2005 is larger than the observed increase by about 0.4 C. This is consistent with the fact that the CCSM4 does not include a representation of the indirect effects of aerosols, although other factors may come into play. The CCSM4 still has significant biases, such as the mean precipitation distribution in the tropical Pacific Ocean, too much low cloud in the Arctic, and the latitudinal distributions of short-wave and long-wave cloud forcings.

  17. Overview of ASC Capability Computing System Governance Model

    SciTech Connect

    Doebling, Scott W.

    2012-07-11

    This document contains a description of the Advanced Simulation and Computing Program's Capability Computing System Governance Model. Objectives of the Governance Model are to ensure that the capability system resources are allocated on a priority-driven basis according to the Program requirements; and to utilize ASC Capability Systems for the large capability jobs for which they were designed and procured.

  18. Trends in reliability modeling technology for fault tolerant systems

    NASA Technical Reports Server (NTRS)

    Bavuso, S. J.

    1979-01-01

    Reliability modeling for fault tolerant avionic computing systems was developed. The modeling of large systems involving issues of state size and complexity, fault coverage, and practical computation was discussed. A novel technique which provides the tool for studying the reliability of systems with nonconstant failure rates is presented. The fault latency which may provide a method of obtaining vital latent fault data is measured.

  19. An investigation of simple nonsmooth power system models

    SciTech Connect

    Mantri, R.; Venkatasubramanian, V.; Saberi, A.

    1994-12-31

    Recently new notions of solutions and equilibrium points have been proposed for analyzing nonsmooth system descriptions. This paper observes certain new phenomena in simple nonsmooth power system models presenting a preliminary analysis. The results include an investigation of new Hopf-like bifurcations related to the birth of limit cycles in two dimensional non-Lipschitzian power system models.

  20. Engineered Barrier System: Physical and Chemical Environment Model

    SciTech Connect

    D. M. Jolley; R. Jarek; P. Mariner

    2004-02-09

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  1. Adaptive Modeling of the International Space Station Electrical Power System

    NASA Technical Reports Server (NTRS)

    Thomas, Justin Ray

    2007-01-01

    Software simulations provide NASA engineers the ability to experiment with spacecraft systems in a computer-imitated environment. Engineers currently develop software models that encapsulate spacecraft system behavior. These models can be inaccurate due to invalid assumptions, erroneous operation, or system evolution. Increasing accuracy requires manual calibration and domain-specific knowledge. This thesis presents a method for automatically learning system models without any assumptions regarding system behavior. Data stream mining techniques are applied to learn models for critical portions of the International Space Station (ISS) Electrical Power System (EPS). We also explore a knowledge fusion approach that uses traditional engineered EPS models to supplement the learned models. We observed that these engineered EPS models provide useful background knowledge to reduce predictive error spikes when confronted with making predictions in situations that are quite different from the training scenarios used when learning the model. Evaluations using ISS sensor data and existing EPS models demonstrate the success of the adaptive approach. Our experimental results show that adaptive modeling provides reductions in model error anywhere from 80% to 96% over these existing models. Final discussions include impending use of adaptive modeling technology for ISS mission operations and the need for adaptive modeling in future NASA lunar and Martian exploration.

  2. Representing natural and manmade drainage systems in an earth system modeling framework

    SciTech Connect

    Li, Hongyi; Wu, Huan; Huang, Maoyi; Leung, Lai-Yung R.

    2012-08-27

    Drainage systems can be categorized into natural or geomorphological drainage systems, agricultural drainage systems and urban drainage systems. They interact closely among themselves and with climate and human society, particularly under extreme climate and hydrological events such as floods. This editorial articulates the need to holistically understand and model drainage systems in the context of climate change and human influence, and discusses the requirements and examples of feasible approaches to representing natural and manmade drainage systems in an earth system modeling framework.

  3. 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

  4. Systemic risk: the dynamics of model banking systems

    PubMed Central

    May, Robert M.; Arinaminpathy, Nimalan

    2010-01-01

    The recent banking crises have made it clear that increasingly complex strategies for managing risk in individual banks have not been matched by corresponding attention to overall systemic risks. We explore some simple mathematical caricatures for ‘banking ecosystems’, with emphasis on the interplay between the characteristics of individual banks (capital reserves in relation to total assets, etc.) and the overall dynamical behaviour of the system. The results are discussed in relation to potential regulations aimed at reducing systemic risk. PMID:19864264

  5. Modeling and Identification of a Large Gap Magnetic Suspension System

    NASA Technical Reports Server (NTRS)

    Cox, David E. (Editor); Groom, Nelson J. (Editor); Hsiao, Min-Hung; Huang, Jen-Kuang

    1996-01-01

    This paper presents the results of modeling and system identification efforts on the NASA Large-Angle Magnetic Suspension Test Fixture (LAMSTF). The LAMSTF consists of a cylindrical permanent magnet which is levitated above a planar array of five electromagnets mounted in a circular configuration. The analytical model is first developed and open-loop characteristics are described. The system is shown to be highly unstable and requires feedback control in order to apply system identification. Limitations on modeling accuracy due to the effect of eddy-currents on the system are discussed. An algorithm is derived to identify a state-space model for the system from input/output data acquired during closed-loop operation. The algorithm is tested on both the baseline system and a perturbed system which has an increased presence of eddy currents. It is found that for the baseline system the analytic model adequately captures the dynamics, although the identified model improves the simulation accuracy. For the system perturbed by additional unmodeled eddy-currents the analytic model is no longer adequate and a higher-order model, determined through system identification, is required to accurately predict the system's time response.

  6. RELAP5 MODEL OF THE DIVERTOR PRIMARY HEAT TRANSFER SYSTEM

    SciTech Connect

    Popov, Emilian L; Yoder Jr, Graydon L; Kim, Seokho H

    2010-08-01

    This report describes the RELAP5 model that has been developed for the divertor primary heat transfer system (PHTS). The model is intended to be used to examine the transient performance of the divertor PHTS and evaluate control schemes necessary to maintain parameters within acceptable limits during transients. Some preliminary results are presented to show the maturity of the model and examine general divertor PHTS transient behavior. The model can be used as a starting point for developing transient modeling capability, including control system modeling, safety evaluations, etc., and is not intended to represent the final divertor PHTS design. Preliminary calculations using the models indicate that during normal pulsed operation, present pressurizer controls may not be sufficient to keep system pressures within their desired range. Additional divertor PHTS and control system design efforts may be required to ensure system pressure fluctuation during normal operation remains within specified limits.

  7. Microphysics in Multi-scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2012-01-01

    Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (1) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, a review of developments and applications of the multi-scale modeling system will be presented. In particular, the microphysics development and its performance for the multi-scale modeling system will be presented.

  8. Techniques for Developing an Elementary Teacher Education Model. A Short Review of Models, Systems Analysis, and Learning Systems.

    ERIC Educational Resources Information Center

    Le Baron, Walt

    A basic introduction to the planning techniques required in the development of elementary teacher education models in presented. Educational models, systems analysis, and learning systems are explained in some detail, with emphasis on the development from symbolic analogy through mechanical, biological, cybernetic, and economic models. A good…

  9. Model abstraction results using state-space system identifications

    NASA Astrophysics Data System (ADS)

    Popken, Douglas A.

    2000-06-01

    In this paper we report on state-space system identification approaches to dynamic behavioral abstraction of military simulation models. Two stochastic simulation models were identified under a variety of scenarios. The `Attrition Simulation' is a model of two opposing forces with multiple weapon system types. The `Mission Simulation' is a model of a squadron of aircraft performing battlefield air interdiction. Four system identification techniques: Maximum Entropy, Compartmental Models, Canonical State-Space Models, and Hidden Markov Models (HMM), were applied to these simulation models. The system identification techniques were evaluated on how well their resulting abstractions replicated the distributions of the simulation states as well as the decision outputs. Encouraging results were achieved by the HMM technique applied to the Attrition Simulation--and by the Maximum Entropy technique applied to the Mission Simulation.

  10. THE EPA MULTIMEDIA INTEGRATED MODELING SYSTEM SOFTWARE SUITE

    EPA Science Inventory

    The U.S. EPA is developing a Multimedia Integrated Modeling System (MIMS) framework that will provide a software infrastructure or environment to support constructing, composing, executing, and evaluating complex modeling studies. The framework will include (1) common software ...

  11. Modeling and Analysis of CSP Systems (Fact Sheet)

    SciTech Connect

    Not Available

    2010-08-01

    Fact sheet describing NREL CSP Program capabilities in the area of modeling and analysis of CSP systems: assessing the solar resource, predicting performance and cost, studying environmental impact, and developing modeling software packages.

  12. Models used to assess the performance of photovoltaic systems.

    SciTech Connect

    Stein, Joshua S.; Klise, Geoffrey T.

    2009-12-01

    This report documents the various photovoltaic (PV) performance models and software developed and utilized by researchers at Sandia National Laboratories (SNL) in support of the Photovoltaics and Grid Integration Department. In addition to PV performance models, hybrid system and battery storage models are discussed. A hybrid system using other distributed sources and energy storage can help reduce the variability inherent in PV generation, and due to the complexity of combining multiple generation sources and system loads, these models are invaluable for system design and optimization. Energy storage plays an important role in reducing PV intermittency and battery storage models are used to understand the best configurations and technologies to store PV generated electricity. Other researcher's models used by SNL are discussed including some widely known models that incorporate algorithms developed at SNL. There are other models included in the discussion that are not used by or were not adopted from SNL research but may provide some benefit to researchers working on PV array performance, hybrid system models and energy storage. The paper is organized into three sections to describe the different software models as applied to photovoltaic performance, hybrid systems, and battery storage. For each model, there is a description which includes where to find the model, whether it is currently maintained and any references that may be available. Modeling improvements underway at SNL include quantifying the uncertainty of individual system components, the overall uncertainty in modeled vs. measured results and modeling large PV systems. SNL is also conducting research into the overall reliability of PV systems.

  13. Modeling Physical Systems Using Vensim PLE Systems Dynamics Software

    ERIC Educational Resources Information Center

    Widmark, Stephen

    2012-01-01

    Many physical systems are described by time-dependent differential equations or systems of such equations. This makes it difficult for students in an introductory physics class to solve many real-world problems since these students typically have little or no experience with this kind of mathematics. In my high school physics classes, I address…

  14. Teratological research using in vitro systems. V. Nonmammalian model systems.

    PubMed Central

    Collins, T F

    1987-01-01

    In this review of alternative tests to whole-animal rodent studies, the use of sub-mammalian and sub-vertebrate systems is investigated. The history, methodology, known limitations, end points, dose response, and requirements of virus, hydra, planarian, cricket, fish, amphibia, Drosophila, and chicken embryo systems are discussed. PMID:3113934

  15. Model documentation: Natural gas transmission and distribution model of the National Energy Modeling System. Volume 1

    SciTech Connect

    1995-02-17

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of integrated Analysis and Forecasting of the Energy information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. The NGTDM is the model within the NEMS that represents the transmission, distribution, and pricing of natural gas. The model also includes representations of the end-use demand for natural gas, the production of domestic natural gas, and the availability of natural gas traded on the international market based on information received from other NEMS models. The NGTDM determines the flow of natural gas in an aggregate, domestic pipeline network, connecting domestic and foreign supply regions with 12 demand regions. The methodology employed allows the analysis of impacts of regional capacity constraints in the interstate natural gas pipeline network and the identification of pipeline capacity expansion requirements. There is an explicit representation of core and noncore markets for natural gas transmission and distribution services, and the key components of pipeline tariffs are represented in a pricing algorithm. Natural gas pricing and flow patterns are derived by obtaining a market equilibrium across the three main elements of the natural gas market: the supply element, the demand element, and the transmission and distribution network that links them. The NGTDM consists of four modules: the Annual Flow Module, the Capacity F-expansion Module, the Pipeline Tariff Module, and the Distributor Tariff Module. A model abstract is provided in Appendix A.

  16. Detailed Performance Model for Photovoltaic Systems: Preprint

    SciTech Connect

    Tian, H.; Mancilla-David, F.; Ellis, K.; Muljadi, E.; Jenkins, P.

    2012-07-01

    This paper presents a modified current-voltage relationship for the single diode model. The single-diode model has been derived from the well-known equivalent circuit for a single photovoltaic cell. The modification presented in this paper accounts for both parallel and series connections in an array.

  17. Conceptual Model of Multidimensional Marketing Information System

    NASA Astrophysics Data System (ADS)

    Kriksciuniene, Dalia; Urbanskiene, Ruta

    This article is aimed to analyse, why the information systems at the enterprise not always satisfy the expectations of marketing management specialists. The computerized systems more and more successfully serve information needs of those areas of enterprise management, where they can create the information equivalent of real management processes. Yet their inability to effectively fulfill marketing needs indicate the gaps not only in ability to structure marketing processes, but in the conceptual development of marketing information systems (MkIS) as well.

  18. Verifying Multi-Agent Systems via Unbounded Model Checking

    NASA Technical Reports Server (NTRS)

    Kacprzak, M.; Lomuscio, A.; Lasica, T.; Penczek, W.; Szreter, M.

    2004-01-01

    We present an approach to the problem of verification of epistemic properties in multi-agent systems by means of symbolic model checking. In particular, it is shown how to extend the technique of unbounded model checking from a purely temporal setting to a temporal-epistemic one. In order to achieve this, we base our discussion on interpreted systems semantics, a popular semantics used in multi-agent systems literature. We give details of the technique and show how it can be applied to the well known train, gate and controller problem. Keywords: model checking, unbounded model checking, multi-agent systems

  19. Electrical Lumped Model Examination for Load Variation of Circulation System

    NASA Astrophysics Data System (ADS)

    Koya, Yoshiharu; Ito, Mitsuyo; Mizoshiri, Isao

    Modeling and analysis of the circulation system enables the characteristic decision of circulation system in the body to be made. So, many models of circulation system have been proposed. But, they are complicated because the models include a lot of elements. Therefore, we proposed a complete circulation model as a lumped electrical circuit, which is comparatively simple. In this paper, we examine the effectiveness of the complete circulation model as a lumped electrical circuit. We use normal, angina pectoris, dilated cardiomyopathy and myocardial infarction for evaluation of the ventricular contraction function.

  20. Learning (from) the errors of a systems biology model.

    PubMed

    Engelhardt, Benjamin; Frőhlich, Holger; Kschischo, Maik

    2016-01-01

    Mathematical modelling is a labour intensive process involving several iterations of testing on real data and manual model modifications. In biology, the domain knowledge guiding model development is in many cases itself incomplete and uncertain. A major problem in this context is that biological systems are open. Missed or unknown external influences as well as erroneous interactions in the model could thus lead to severely misleading results. Here we introduce the dynamic elastic-net, a data driven mathematical method which automatically detects such model errors in ordinary differential equation (ODE) models. We demonstrate for real and simulated data, how the dynamic elastic-net approach can be used to automatically (i) reconstruct the error signal, (ii) identify the target variables of model error, and (iii) reconstruct the true system state even for incomplete or preliminary models. Our work provides a systematic computational method facilitating modelling of open biological systems under uncertain knowledge. PMID:26865316

  1. Learning (from) the errors of a systems biology model

    NASA Astrophysics Data System (ADS)

    Engelhardt, Benjamin; Frőhlich, Holger; Kschischo, Maik

    2016-02-01

    Mathematical modelling is a labour intensive process involving several iterations of testing on real data and manual model modifications. In biology, the domain knowledge guiding model development is in many cases itself incomplete and uncertain. A major problem in this context is that biological systems are open. Missed or unknown external influences as well as erroneous interactions in the model could thus lead to severely misleading results. Here we introduce the dynamic elastic-net, a data driven mathematical method which automatically detects such model errors in ordinary differential equation (ODE) models. We demonstrate for real and simulated data, how the dynamic elastic-net approach can be used to automatically (i) reconstruct the error signal, (ii) identify the target variables of model error, and (iii) reconstruct the true system state even for incomplete or preliminary models. Our work provides a systematic computational method facilitating modelling of open biological systems under uncertain knowledge.

  2. Learning (from) the errors of a systems biology model.

    PubMed

    Engelhardt, Benjamin; Frőhlich, Holger; Kschischo, Maik

    2016-02-11

    Mathematical modelling is a labour intensive process involving several iterations of testing on real data and manual model modifications. In biology, the domain knowledge guiding model development is in many cases itself incomplete and uncertain. A major problem in this context is that biological systems are open. Missed or unknown external influences as well as erroneous interactions in the model could thus lead to severely misleading results. Here we introduce the dynamic elastic-net, a data driven mathematical method which automatically detects such model errors in ordinary differential equation (ODE) models. We demonstrate for real and simulated data, how the dynamic elastic-net approach can be used to automatically (i) reconstruct the error signal, (ii) identify the target variables of model error, and (iii) reconstruct the true system state even for incomplete or preliminary models. Our work provides a systematic computational method facilitating modelling of open biological systems under uncertain knowledge.

  3. Learning (from) the errors of a systems biology model

    PubMed Central

    Engelhardt, Benjamin; Frőhlich, Holger; Kschischo, Maik

    2016-01-01

    Mathematical modelling is a labour intensive process involving several iterations of testing on real data and manual model modifications. In biology, the domain knowledge guiding model development is in many cases itself incomplete and uncertain. A major problem in this context is that biological systems are open. Missed or unknown external influences as well as erroneous interactions in the model could thus lead to severely misleading results. Here we introduce the dynamic elastic-net, a data driven mathematical method which automatically detects such model errors in ordinary differential equation (ODE) models. We demonstrate for real and simulated data, how the dynamic elastic-net approach can be used to automatically (i) reconstruct the error signal, (ii) identify the target variables of model error, and (iii) reconstruct the true system state even for incomplete or preliminary models. Our work provides a systematic computational method facilitating modelling of open biological systems under uncertain knowledge. PMID:26865316

  4. Effect of attenuation models on communication system design

    NASA Technical Reports Server (NTRS)

    Shimabukuro, Fred I.

    1995-01-01

    The atmosphere has a significant impact on the design of a global communication system operating at 20 GHz. The system under consideration has a total atmospheric link attenuation budget that is less than 6 dB. For this relatively small link margin, rain, cloud, and molecular attenuation have to be taken into account. For an assessment of system performance on a global basis, attenuation models are utilized. There is concern whether current models can adequately describe the atmospheric effects such that a system planner can properly allocate his resources for superior overall system performance. The atmospheric attenuation as predicted by models will be examined.

  5. Application of nonlinear time series models to driven systems

    SciTech Connect

    Hunter, N.F. Jr.

    1990-01-01

    In our laboratory we have been engaged in an effort to model nonlinear systems using time series methods. Our objectives have been, first, to understand how the time series response of a nonlinear system unfolds as a function of the underlying state variables, second, to model the evolution of the state variables, and finally, to predict nonlinear system responses. We hope to address the relationship between model parameters and system parameters in the near future. Control of nonlinear systems based on experimentally derived parameters is also a planned topic of future research. 28 refs., 15 figs., 2 tabs.

  6. Dynamical system modeling via signal reduction and neural network simulation

    SciTech Connect

    Paez, T.L.; Hunter, N.F.

    1997-11-01

    Many dynamical systems tested in the field and the laboratory display significant nonlinear behavior. Accurate characterization of such systems requires modeling in a nonlinear framework. One construct forming a basis for nonlinear modeling is that of the artificial neural network (ANN). However, when system behavior is complex, the amount of data required to perform training can become unreasonable. The authors reduce the complexity of information present in system response measurements using decomposition via canonical variate analysis. They describe a method for decomposing system responses, then modeling the components with ANNs. A numerical example is presented, along with conclusions and recommendations.

  7. Fuzzy modelling of power system optimal load flow

    SciTech Connect

    Miranda, V.; Saraiva, J.T. )

    1992-05-01

    In this paper, a fuzzy model for power system operation is presented. Uncertainties in loads and generations are modeled as fuzzy numbers. System behavior under known (while uncertain) injections is dealt with by a DC fuzzy power flow model. System optimal (while uncertain) operation is calculated with linear programming procedures where the problem nature and structure allows some efficient techniques such as Dantzig Wolfe decomposition and dual simplex to be used. Among the results, one obtains a fuzzy cost value for system operation and possibility distributions for branch power flows and power generations. Some risk analysis is possible, as system robustness and exposure indices can be derived and hedging policies can be investigated.

  8. Distribution system reliability assessment using hierarchical Markov modeling

    SciTech Connect

    Brown, R.E.; Gupta, S.; Christie, R.D.; Venkata, S.S.; Fletcher, R.

    1996-10-01

    Distribution system reliability assessment is concerned with power availability and power quality at each customer`s service entrance. This paper presents a new method, termed Hierarchical Markov Modeling (HMM), which can perform predictive distribution system reliability assessment. HMM is unique in that it decomposes the reliability model based on system topology, integrated protection systems, and individual protection devices. This structure, which easily accommodates the effects of backup protection, fault isolation, and load restoration, is compared to simpler reliability models. HMM is then used to assess the reliability of an existing utility distribution system and to explore the reliability impact of several design improvement options.

  9. System statistical reliability model and analysis

    NASA Technical Reports Server (NTRS)

    Lekach, V. S.; Rood, H.

    1973-01-01

    A digital computer code was developed to simulate the time-dependent behavior of the 5-kwe reactor thermoelectric system. The code was used to determine lifetime sensitivity coefficients for a number of system design parameters, such as thermoelectric module efficiency and degradation rate, radiator absorptivity and emissivity, fuel element barrier defect constant, beginning-of-life reactivity, etc. A probability distribution (mean and standard deviation) was estimated for each of these design parameters. Then, error analysis was used to obtain a probability distribution for the system lifetime (mean = 7.7 years, standard deviation = 1.1 years). From this, the probability that the system will achieve the design goal of 5 years lifetime is 0.993. This value represents an estimate of the degradation reliability of the system.

  10. Some generalisations of linear-graph modelling for dynamic systems

    NASA Astrophysics Data System (ADS)

    de Silva, Clarence W.; Pourazadi, Shahram

    2013-11-01

    Proper modelling of a dynamic system can benefit analysis, simulation, design, evaluation and control of the system. The linear-graph (LG) approach is suitable for modelling lumped-parameter dynamic systems. By using the concepts of graph trees, it provides a graphical representation of the system, with a direct correspondence to the physical component topology. This paper systematically extends the application of LGs to multi-domain (mixed-domain or multi-physics) dynamic systems by presenting a unified way to represent different domains - mechanical, electrical, thermal and fluid. Preservation of the structural correspondence across domains is a particular advantage of LGs when modelling mixed-domain systems. The generalisation of Thevenin and Norton equivalent circuits to mixed-domain systems, using LGs, is presented. The structure of an LG model may follow a specific pattern. Vector LGs are introduced to take advantage of such patterns, giving a general LG representation for them. Through these vector LGs, the model representation becomes simpler and rather compact, both topologically and parametrically. A new single LG element is defined to facilitate the modelling of distributed-parameter (DP) systems. Examples are presented using multi-domain systems (a motion-control system and a flow-controlled pump), a multi-body mechanical system (robot manipulator) and DP systems (structural rods) to illustrate the application and advantages of the methodologies developed in the paper.

  11. Reliability model of a monopropellant auxiliary propulsion system

    NASA Technical Reports Server (NTRS)

    Greenberg, J. S.

    1971-01-01

    A mathematical model and associated computer code has been developed which computes the reliability of a monopropellant blowdown hydrazine spacecraft auxiliary propulsion system as a function of time. The propulsion system is used to adjust or modify the spacecraft orbit over an extended period of time. The multiple orbit corrections are the multiple objectives which the auxiliary propulsion system is designed to achieve. Thus the reliability model computes the probability of successfully accomplishing each of the desired orbit corrections. To accomplish this, the reliability model interfaces with a computer code that models the performance of a blowdown (unregulated) monopropellant auxiliary propulsion system. The computer code acts as a performance model and as such gives an accurate time history of the system operating parameters. The basic timing and status information is passed on to and utilized by the reliability model which establishes the probability of successfully accomplishing the orbit corrections.

  12. A Language for Modelling Trust in Information Systems

    NASA Astrophysics Data System (ADS)

    Bimrah, Kamaljit Kaur; Mouratidis, Haralambos; Preston, David

    It has been argued in recent research that trust is an important issue for modern information systems and that it should be considered from the early stages of the development process. Nevertheless, little effort has been put into understanding how trust can be modelled and reasoned when developing information systems. Equally little effort has been put into developing modelling languages to support trust modelling. Our motivation comes from this situation and we aim to develop a trust-aware modelling framework that will enable information system developers to consider trust and its related concepts collectively during the development of information systems. In this chapter we re-enforce the argument about the need to consider trust during information systems development and we describe a modelling language that supports trust modelling. We employ a case study from a trust critical domain to demonstrate the application of our language.

  13. Major remaining gaps in models of sensorimotor systems

    PubMed Central

    Loeb, Gerald E.; Tsianos, George A.

    2015-01-01

    Experimental descriptions of the anatomy and physiology of individual components of sensorimotor systems have revealed substantial complexity, making it difficult to intuit how complete systems might work. This has led to increasing efforts to develop and employ mathematical models to study the emergent properties of such systems. Conversely, the development of such models tends to reveal shortcomings in the experimental database upon which models must be constructed and validated. In both cases models are most useful when they point up discrepancies between what we think we know and possibilities that we may have overlooked. This overview considers those components of complete sensorimotor systems that currently appear to be potentially important but poorly understood. These are generally omitted completely from modeled systems or buried in implicit assumptions that underlie the design of the model. PMID:26089795

  14. Representing plant hydraulics in a global Earth system model.

    NASA Astrophysics Data System (ADS)

    Kennedy, D.; Gentine, P.

    2015-12-01

    Earth system models need improvement to reproduce observed seasonal and diurnal cycles of photosynthesis and respiration. Model water stress parameterizations lag behind the plant physiology literature. A plant hydraulics model is developed and deployed in a global Earth system model (NCAR CESM 1.2.2 with CLM 4.5). Assimilation and transpiration are attenuated according to literature cavitation curves. Water stress is evaluated based on plant functional type hydraulic parameters forced by soil moisture and atmospheric conditions. Resolving the plant water status allows for modelling divergent strategies for water stress. The case of isohydric versus anisohydric species is presented, showing that including plant hydraulic traits alter modelled photosynthesis and transpiration.

  15. A synchronous paradigm for modeling stable reactive systems

    SciTech Connect

    Winter, V.L.

    1998-12-01

    This paper describes a modeling technique for single-agent reactive systems, that is influenced by the modeling paradigm of Parnas as well as by the synchronous paradigms of LUSTRE and ESTEREL. In this paradigm, single-agent reactive systems are modeled in a universe having a discrete clock. This discretization of time greatly reduces the temporal complexity of the model. He believes that the advantage of this reduction in temporal complexity is that the resulting model is in many ways better suited to automated software construction and analysis techniques (e.g., deductive synthesis, transformation, and verification) than models that are based on continuous representations of time.

  16. 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.

  17. Process modeling for the Integrated Nonthermal Treatment System (INTS) study

    SciTech Connect

    Brown, B.W.

    1997-04-01

    This report describes the process modeling done in support of the Integrated Nonthermal Treatment System (INTS) study. This study was performed to supplement the Integrated Thermal Treatment System (ITTS) study and comprises five conceptual treatment systems that treat DOE contract-handled mixed low-level wastes (MLLW) at temperatures of less than 350{degrees}F. ASPEN PLUS, a chemical process simulator, was used to model the systems. Nonthermal treatment systems were developed as part of the INTS study and include sufficient processing steps to treat the entire inventory of MLLW. The final result of the modeling is a process flowsheet with a detailed mass and energy balance. In contrast to the ITTS study, which modeled only the main treatment system, the INTS study modeled each of the various processing steps with ASPEN PLUS, release 9.1-1. Trace constituents, such as radionuclides and minor pollutant species, were not included in the calculations.

  18. On The Modeling of Educational Systems: II

    ERIC Educational Resources Information Center

    Grauer, Robert T.

    1975-01-01

    A unified approach to model building is developed from the separate techniques of regression, simulation, and factorial design. The methodology is applied in the context of a suburban school district. (Author/LS)

  19. Modeling vaccination in a heterogeneous metapopulation system

    NASA Astrophysics Data System (ADS)

    Lachiany, Menachem

    2016-09-01

    We present here a multicity SIS epidemic model with vaccination. The model describes the dynamics of heterogeneous metapopulations that contain imperfectly vaccinated individuals. The effect of vaccination on heterogeneous multicity models has not been previously studied. We show that under very generic conditions, the epidemic threshold does not depend on the diffusion coefficient of the vaccinated individuals, but it does depend on the diffusion coefficient of the infected population. We then show, using a novel methodology, that the reproduction number is determined by the homogeneous model parameters and by the maximal number of neighbors a city can have, when the diffusion coefficient of the infected population is low. Finally, we present numerical simulations to support the analytical results.

  20. Aggregated models for integrated distillation systems

    SciTech Connect

    Caballero, J.A.; Grossmann, I.E.

    1999-06-01

    In this work the authors present an aggregated representation for distillation columns that can be used in the synthesis of separation sequences with heat integration. A new aggregated model is first presented for the stripping and rectifying sections of individual distillation columns. This model is based on mass balances and equilibrium feasibility, expressed in terms of flows, inlet concentrations, and recoveries. The energy balance can then be decoupled from the mass balance, and the utilities can be calculated for each separation task. The proposed model is applied to three different superstructures: state task network, state equipment network, and an intermediate representation. The proposed model yields a lower bound to the vapor flow or to the total cost of the utilities. Performance of the different superstructure representations in terms of robustness and computational time is illustrated with several examples.

  1. MODELING CONTAMINANT TRANSPORT THROUGH SUBSURFACE SYSTEMS

    EPA Science Inventory

    Modeling of contaminant transport through soil to groundwater to a receptor requires that consideration be given to the many processes which control the transport and fate of chemical constituents in the subsurface environment. These processes include volatilization, degradation,...

  2. The design and implementation of an operational model evaluation system

    SciTech Connect

    Foster, K.T.

    1995-06-01

    An evaluation of an atmospheric transport and diffusion model`s operational performance typically involves the comparison of the model`s calculations with measurements of an atmospheric pollutant`s temporal and spatial distribution. These evaluations however often use data from a small number of experiments and may be limited to producing some of the commonly quoted statistics based on the differences between model calculations and the measurements. This paper presents efforts to develop a model evaluation system geared for both the objective statistical analysis and the more subjective visualization of the inter-relationships between a model`s calculations and the appropriate field measurement data.

  3. Towards a Model-Driven Approach to Information System Evolution

    NASA Astrophysics Data System (ADS)

    Aboulsamh, Mohammed; Davies, Jim

    Models have always played an important role in information systems (IS) design: typically, entity-relationship diagrams or object models have been used to describe data structures and the relationships between them. Model transformation and code generation technologies have given models an even more important role: as part of the source code for the system. This "model-driven" approach, however, has application beyond initial implementation. This chapter shows how subsequent changes to a design, captured as an "evolution model", can be used to generate the data transformations required for the migration of data between different versions of the same system. The intention is to facilitate the adaptation of systems to changing requirements, using model-driven technologies for the rapid development of new versions, by reducing the cost and increasing the reliability of each migration step.

  4. High pressure common rail injection system modeling and control.

    PubMed

    Wang, H P; Zheng, D; Tian, Y

    2016-07-01

    In this paper modeling and common-rail pressure control of high pressure common rail injection system (HPCRIS) is presented. The proposed mathematical model of high pressure common rail injection system which contains three sub-systems: high pressure pump sub-model, common rail sub-model and injector sub-model is a relative complicated nonlinear system. The mathematical model is validated by the software Matlab and a virtual detailed simulation environment. For the considered HPCRIS, an effective model free controller which is called Extended State Observer - based intelligent Proportional Integral (ESO-based iPI) controller is designed. And this proposed method is composed mainly of the referred ESO observer, and a time delay estimation based iPI controller. Finally, to demonstrate the performances of the proposed controller, the proposed ESO-based iPI controller is compared with a conventional PID controller and ADRC. PMID:27012440

  5. Modular reliability modeling of the TJNAF personnel safety system

    SciTech Connect

    Cinnamon, J.; Mahoney, K.

    1997-08-01

    A reliability model for the Thomas Jefferson National Accelerator Facility (formerly CEBAF) personnel safety system has been developed. The model, which was implemented using an Excel spreadsheet, allows simulation of all or parts of the system. Modularity os the model`s implementation allows rapid {open_quotes}what if{open_quotes} case studies to simulate change in safety system parameters such as redundancy, diversity, and failure rates. Particular emphasis is given to the prediction of failure modes which would result in the failure of both of the redundant safety interlock systems. In addition to the calculation of the predicted reliability of the safety system, the model also calculates availability of the same system. Such calculations allow the user to make tradeoff studies between reliability and availability, and to target resources to improving those parts of the system which would most benefit from redesign or upgrade. The model includes calculated, manufacturer`s data, and Jefferson Lab field data. This paper describes the model, methods used, and comparison of calculated to actual data for the Jefferson Lab personnel safety system. Examples are given to illustrate the model`s utility and ease of use.

  6. Service models for remote healthcare monitoring systems.

    PubMed

    Moorman, Bridget A

    2010-01-01

    These scenarios reflect where the future is heading for remote health monitoring technology and service expectations. Being able to manage a "system of systems" with timely service hand-off over seams of responsibility and system interfaces will become very important for a BMET or clinical engineer. These interfaces will include patient homes, clinician homes, commercial/civilian infrastructure, public utilities, vendor infrastructure as well as internal departmental domains. Concurrently, technology is changing rapidly resulting in newer software delivery modes and hardware appliances as well as infrastructure changes. Those who are able to de-construct the complex systems and identify infrastructure assumptions and seams of servicing responsibility will be able to better understand and communicate the expectations for service of these systems. Moreover, as identified in Case 1, prodigious use of underlying system monitoring tools (managing the "meta-data") could move servicing of these remote systems from a reactive approach to a proactive approach. A prepared healthcare organization will identify their current and proposed future service combination use cases and design service philosophies and expectations for those use cases, while understanding the infrastructure assumptions and seams of responsibility. This is the future of technical service to the healthcare clinicians and patients. PMID:22049611

  7. Transient upset models in computer systems

    NASA Technical Reports Server (NTRS)

    Mason, G. M.

    1983-01-01

    Essential factors for the design of transient upset monitors for computers are discussed. The upset is a system level event that is software dependent. It can occur in the program flow, the opcode set, the opcode address domain, the read address domain, and the write address domain. Most upsets are in the program flow. It is shown that simple, external monitors functioning transparently relative to the system operations can be built if a detailed accounting is made of the characteristics of the faults that can happen. Sample applications are provided for different states of the Z-80 and 8085 based system.

  8. Business model for sensor-based fall recognition systems.

    PubMed

    Fachinger, Uwe; Schöpke, Birte

    2014-01-01

    AAL systems require, in addition to sophisticated and reliable technology, adequate business models for their launch and sustainable establishment. This paper presents the basic features of alternative business models for a sensor-based fall recognition system which was developed within the context of the "Lower Saxony Research Network Design of Environments for Ageing" (GAL). The models were developed parallel to the R&D process with successive adaptation and concretization. An overview of the basic features (i.e. nine partial models) of the business model is given and the mutual exclusive alternatives for each partial model are presented. The partial models are interconnected and the combinations of compatible alternatives lead to consistent alternative business models. However, in the current state, only initial concepts of alternative business models can be deduced. The next step will be to gather additional information to work out more detailed models.

  9. Markov reliability models for digital flight control systems

    NASA Technical Reports Server (NTRS)

    Mcgough, John; Reibman, Andrew; Trivedi, Kishor

    1989-01-01

    The reliability of digital flight control systems can often be accurately predicted using Markov chain models. The cost of numerical solution depends on a model's size and stiffness. Acyclic Markov models, a useful special case, are particularly amenable to efficient numerical solution. Even in the general case, instantaneous coverage approximation allows the reduction of some cyclic models to more readily solvable acyclic models. After considering the solution of single-phase models, the discussion is extended to phased-mission models. Phased-mission reliability models are classified based on the state restoration behavior that occurs between mission phases. As an economical approach for the solution of such models, the mean failure rate solution method is introduced. A numerical example is used to show the influence of fault-model parameters and interphase behavior on system unreliability.

  10. Requirements based system level risk modeling

    NASA Technical Reports Server (NTRS)

    Meshkat, L.; Cornford, S. L.; Feather, M. S.

    2004-01-01

    The problem that we address in this paper is assessing the expected degree of success of the system or mission based on the degree to which each requirement is satisfied and the relative weight of the requirements.

  11. 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).

  12. Applying Model Based Systems Engineering to NASA's Space Communications Networks

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Barnes, Patrick; Reinert, Jessica; Golden, Bert

    2013-01-01

    System engineering practices for complex systems and networks now require that requirement, architecture, and concept of operations product development teams, simultaneously harmonize their activities to provide timely, useful and cost-effective products. When dealing with complex systems of systems, traditional systems engineering methodology quickly falls short of achieving project objectives. This approach is encumbered by the use of a number of disparate hardware and software tools, spreadsheets and documents to grasp the concept of the network design and operation. In case of NASA's space communication networks, since the networks are geographically distributed, and so are its subject matter experts, the team is challenged to create a common language and tools to produce its products. Using Model Based Systems Engineering methods and tools allows for a unified representation of the system in a model that enables a highly related level of detail. To date, Program System Engineering (PSE) team has been able to model each network from their top-level operational activities and system functions down to the atomic level through relational modeling decomposition. These models allow for a better understanding of the relationships between NASA's stakeholders, internal organizations, and impacts to all related entities due to integration and sustainment of existing systems. Understanding the existing systems is essential to accurate and detailed study of integration options being considered. In this paper, we identify the challenges the PSE team faced in its quest to unify complex legacy space communications networks and their operational processes. We describe the initial approaches undertaken and the evolution toward model based system engineering applied to produce Space Communication and Navigation (SCaN) PSE products. We will demonstrate the practice of Model Based System Engineering applied to integrating space communication networks and the summary of its

  13. Model Transformation for a System of Systems Dependability Safety Case

    NASA Technical Reports Server (NTRS)

    Murphy, Judy; Driskell, Steve

    2011-01-01

    The presentation reviews the dependability and safety effort of NASA's Independent Verification and Validation Facility. Topics include: safety engineering process, applications to non-space environment, Phase I overview, process creation, sample SRM artifact, Phase I end result, Phase II model transformation, fault management, and applying Phase II to individual projects.

  14. Multiscale modeling of integrated CCS systems

    NASA Astrophysics Data System (ADS)

    Alhajaj, Ahmed; Shah, Nilay

    2015-01-01

    The world will continue consuming fossil fuel within the coming decades to meet its growing energy demand; however, this source must be cleaner through implementation of carbon capture, transport and storage (CCTS). This process is complex and involves multiple phases, owned by different operational companies and stakeholders with different business models and regulatory framework. The objective of this work is to develop a multiscale modeling approach to link process models, post-combustion capture plant model and network design models under an optimization framework in order to design and analyse the cost optimal CO2 infrastructure that match CO2 sources and sinks in capacity and time. The network comprises a number of CO2 sources at fixed locations and a number of potential CO2 storage sites. The decisions to be determined include from which sources it is appropriate to capture CO2 and the cost-optimal degree-of-capture (DOC) for a given source and the infrastructural layout of the CO2 transmission network.

  15. Parameter identifiability of power-law biochemical system models.

    PubMed

    Srinath, Sridharan; Gunawan, Rudiyanto

    2010-09-01

    Mathematical modeling has become an integral component in biotechnology, in which these models are frequently used to design and optimize bioprocesses. Canonical models, like power-laws within the Biochemical Systems Theory, offer numerous mathematical and numerical advantages, including built-in flexibility to simulate general nonlinear behavior. The construction of such models relies on the estimation of unknown case-specific model parameters by way of experimental data fitting, also known as inverse modeling. Despite the large number of publications on this topic, this task remains the bottleneck in canonical modeling of biochemical systems. The focus of this paper concerns with the question of identifiability of power-law models from dynamic data, that is, whether the parameter values can be uniquely and accurately identified from time-series data. Existing and newly developed parameter identifiability methods were applied to two power-law models of biochemical systems, and the results pointed to the lack of parametric identifiability as the root cause of the difficulty faced in the inverse modeling. Despite the focus on power-law models, the analyses and conclusions are extendable to other canonical models, and the issue of parameter identifiability is expected to be a common problem in biochemical system modeling. PMID:20197073

  16. Diagnosing Hybrid Systems: a Bayesian Model Selection Approach

    NASA Technical Reports Server (NTRS)

    McIlraith, Sheila A.

    2005-01-01

    In this paper we examine the problem of monitoring and diagnosing noisy complex dynamical systems that are modeled as hybrid systems-models of continuous behavior, interleaved by discrete transitions. In particular, we examine continuous systems with embedded supervisory controllers that experience abrupt, partial or full failure of component devices. Building on our previous work in this area (MBCG99;MBCG00), our specific focus in this paper ins on the mathematical formulation of the hybrid monitoring and diagnosis task as a Bayesian model tracking algorithm. The nonlinear dynamics of many hybrid systems present challenges to probabilistic tracking. Further, probabilistic tracking of a system for the purposes of diagnosis is problematic because the models of the system corresponding to failure modes are numerous and generally very unlikely. To focus tracking on these unlikely models and to reduce the number of potential models under consideration, we exploit logic-based techniques for qualitative model-based diagnosis to conjecture a limited initial set of consistent candidate models. In this paper we discuss alternative tracking techniques that are relevant to different classes of hybrid systems, focusing specifically on a method for tracking multiple models of nonlinear behavior simultaneously using factored sampling and conditional density propagation. To illustrate and motivate the approach described in this paper we examine the problem of monitoring and diganosing NASA's Sprint AERCam, a small spherical robotic camera unit with 12 thrusters that enable both linear and rotational motion.

  17. Data model for system conceptulization in groundwater studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of a conceptualization of a hydrogeologic system serves as the basis of groundwater modeling. While existing groundwater data models are designed to store groundwater system information, none is designed to capture its conceptual view. This study addresses this need by presenting a new o...

  18. A voice-actuated wind tunnel model leak checking system

    NASA Technical Reports Server (NTRS)

    Larson, W. E.

    1985-01-01

    A voice-actuated wind tunnel model leak checking system was developed. The system uses a voice recognition and response unit to interact with the technician along with a graphics terminal to provide the technician with visual feedback while checking a model for leaks.

  19. 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…

  20. Rhode Island Model Evaluation & Support System: Support Professional. Edition II

    ERIC Educational Resources Information Center

    Rhode Island Department of Education, 2015

    2015-01-01

    Rhode Island educators believe that implementing a fair, accurate, and meaningful evaluation and support system for support professionals will help improve student outcomes. The primary purpose of the Rhode Island Model Support Professional Evaluation and Support System (Rhode Island Model) is to help all support professionals do their best work…

  1. Rhode Island Model Evaluation & Support System: Building Administrator. Edition III

    ERIC Educational Resources Information Center

    Rhode Island Department of Education, 2015

    2015-01-01

    Rhode Island educators believe that implementing a fair, accurate, and meaningful educator evaluation and support system will help improve teaching, learning, and school leadership. The primary purpose of the Rhode Island Model Building Administrator Evaluation and Support System (Rhode Island Model) is to help all building administrators improve.…

  2. A Computer Model of the Cardiovascular System for Effective Learning.

    ERIC Educational Resources Information Center

    Rothe, Carl F.

    1980-01-01

    Presents a model of the cardiovascular system which solves a set of interacting, possibly nonlinear, differential equations. Figures present a schematic diagram of the model and printouts that simulate normal conditions, exercise, hemorrhage, reduced contractility. The nine interacting equations used to describe the system are described in the…

  3. Systems in Science: Modeling Using Three Artificial Intelligence Concepts.

    ERIC Educational Resources Information Center

    Sunal, Cynthia Szymanski; Karr, Charles L.; Smith, Coralee; Sunal, Dennis W.

    2003-01-01

    Describes an interdisciplinary course focusing on modeling scientific systems. Investigates elementary education majors' applications of three artificial intelligence concepts used in modeling scientific systems before and after the course. Reveals a great increase in understanding of concepts presented but inconsistent application. (Author/KHR)

  4. 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

  5. A Structural Model Decomposition Framework for Systems Health Management

    NASA Technical Reports Server (NTRS)

    Roychoudhury, Indranil; Daigle, Matthew J.; Bregon, Anibal; Pulido, Belamino

    2013-01-01

    Systems health management (SHM) is an important set of technologies aimed at increasing system safety and reliability by detecting, isolating, and identifying faults; and predicting when the system reaches end of life (EOL), so that appropriate fault mitigation and recovery actions can be taken. Model-based SHM approaches typically make use of global, monolithic system models for online analysis, which results in a loss of scalability and efficiency for large-scale systems. Improvement in scalability and efficiency can be achieved by decomposing the system model into smaller local submodels and operating on these submodels instead. In this paper, the global system model is analyzed offline and structurally decomposed into local submodels. We define a common model decomposition framework for extracting submodels from the global model. This framework is then used to develop algorithms for solving model decomposition problems for the design of three separate SHM technologies, namely, estimation (which is useful for fault detection and identification), fault isolation, and EOL prediction. We solve these model decomposition problems using a three-tank system as a case study.

  6. 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.

  7. OFMTutor: An operator function model intelligent tutoring system

    NASA Technical Reports Server (NTRS)

    Jones, Patricia M.

    1989-01-01

    The design, implementation, and evaluation of an Operator Function Model intelligent tutoring system (OFMTutor) is presented. OFMTutor is intended to provide intelligent tutoring in the context of complex dynamic systems for which an operator function model (OFM) can be constructed. The human operator's role in such complex, dynamic, and highly automated systems is that of a supervisory controller whose primary responsibilities are routine monitoring and fine-tuning of system parameters and occasional compensation for system abnormalities. The automated systems must support the human operator. One potentially useful form of support is the use of intelligent tutoring systems to teach the operator about the system and how to function within that system. Previous research on intelligent tutoring systems (ITS) is considered. The proposed design for OFMTutor is presented, and an experimental evaluation is described.

  8. Integration of Earth System Models and Workflow Management under iRODS for the Northeast Regional Earth System Modeling Project

    NASA Astrophysics Data System (ADS)

    Lengyel, F.; Yang, P.; Rosenzweig, B.; Vorosmarty, C. J.

    2012-12-01

    The Northeast Regional Earth System Model (NE-RESM, NSF Award #1049181) integrates weather research and forecasting models, terrestrial and aquatic ecosystem models, a water balance/transport model, and mesoscale and energy systems input-out economic models developed by interdisciplinary research team from academia and government with expertise in physics, biogeochemistry, engineering, energy, economics, and policy. NE-RESM is intended to forecast the implications of planning decisions on the region's environment, ecosystem services, energy systems and economy through the 21st century. Integration of model components and the development of cyberinfrastructure for interacting with the system is facilitated with the integrated Rule Oriented Data System (iRODS), a distributed data grid that provides archival storage with metadata facilities and a rule-based workflow engine for automating and auditing scientific workflows.

  9. Visual prosthesis wireless energy transfer system optimal modeling

    PubMed Central

    2014-01-01

    Background Wireless energy transfer system is an effective way to solve the visual prosthesis energy supply problems, theoretical modeling of the system is the prerequisite to do optimal energy transfer system design. Methods On the basis of the ideal model of the wireless energy transfer system, according to visual prosthesis application condition, the system modeling is optimized. During the optimal modeling, taking planar spiral coils as the coupling devices between energy transmitter and receiver, the effect of the parasitic capacitance of the transfer coil is considered, and especially the concept of biological capacitance is proposed to consider the influence of biological tissue on the energy transfer efficiency, resulting in the optimal modeling’s more accuracy for the actual application. Results The simulation data of the optimal model in this paper is compared with that of the previous ideal model, the results show that under high frequency condition, the parasitic capacitance of inductance and biological capacitance considered in the optimal model could have great impact on the wireless energy transfer system. The further comparison with the experimental data verifies the validity and accuracy of the optimal model proposed in this paper. Conclusions The optimal model proposed in this paper has a higher theoretical guiding significance for the wireless energy transfer system’s further research, and provide a more precise model reference for solving the power supply problem in visual prosthesis clinical application. PMID:24428906

  10. Electric Propulsion System Modeling for the Proposed Prometheus 1 Mission

    NASA Technical Reports Server (NTRS)

    Fiehler, Douglas; Dougherty, Ryan; Manzella, David

    2005-01-01

    The proposed Prometheus 1 spacecraft would utilize nuclear electric propulsion to propel the spacecraft to its ultimate destination where it would perform its primary mission. As part of the Prometheus 1 Phase A studies, system models were developed for each of the spacecraft subsystems that were integrated into one overarching system model. The Electric Propulsion System (EPS) model was developed using data from the Prometheus 1 electric propulsion technology development efforts. This EPS model was then used to provide both performance and mass information to the Prometheus 1 system model for total system trades. Development of the EPS model is described, detailing both the performance calculations as well as its evolution over the course of Phase A through three technical baselines. Model outputs are also presented, detailing the performance of the model and its direct relationship to the Prometheus 1 technology development efforts. These EP system model outputs are also analyzed chronologically showing the response of the model development to the four technical baselines during Prometheus 1 Phase A.

  11. A method for zooming of nonlinear models of biochemical systems

    PubMed Central

    2011-01-01

    Background Models of biochemical systems are typically complex, which may complicate the discovery of cardinal biochemical principles. It is therefore important to single out the parts of a model that are essential for the function of the system, so that the remaining non-essential parts can be eliminated. However, each component of a mechanistic model has a clear biochemical interpretation, and it is desirable to conserve as much of this interpretability as possible in the reduction process. Furthermore, it is of great advantage if we can translate predictions from the reduced model to the original model. Results In this paper we present a novel method for model reduction that generates reduced models with a clear biochemical interpretation. Unlike conventional methods for model reduction our method enables the mapping of predictions by the reduced model to the corresponding detailed predictions by the original model. The method is based on proper lumping of state variables interacting on short time scales and on the computation of fraction parameters, which serve as the link between the reduced model and the original model. We illustrate the advantages of the proposed method by applying it to two biochemical models. The first model is of modest size and is commonly occurring as a part of larger models. The second model describes glucose transport across the cell membrane in baker's yeast. Both models can be significantly reduced with the proposed method, at the same time as the interpretability is conserved. Conclusions We introduce a novel method for reduction of biochemical models that is compatible with the concept of zooming. Zooming allows the modeler to work on different levels of model granularity, and enables a direct interpretation of how modifications to the model on one level affect the model on other levels in the hierarchy. The method extends the applicability of the method that was previously developed for zooming of linear biochemical models to

  12. Multi-scenario modelling of uncertainty in stochastic chemical systems

    SciTech Connect

    Evans, R. David; Ricardez-Sandoval, Luis A.

    2014-09-15

    Uncertainty analysis has not been well studied at the molecular scale, despite extensive knowledge of uncertainty in macroscale systems. The ability to predict the effect of uncertainty allows for robust control of small scale systems such as nanoreactors, surface reactions, and gene toggle switches. However, it is difficult to model uncertainty in such chemical systems as they are stochastic in nature, and require a large computational cost. To address this issue, a new model of uncertainty propagation in stochastic chemical systems, based on the Chemical Master Equation, is proposed in the present study. The uncertain solution is approximated by a composite state comprised of the averaged effect of samples from the uncertain parameter distributions. This model is then used to study the effect of uncertainty on an isomerization system and a two gene regulation network called a repressilator. The results of this model show that uncertainty in stochastic systems is dependent on both the uncertain distribution, and the system under investigation. -- Highlights: •A method to model uncertainty on stochastic systems was developed. •The method is based on the Chemical Master Equation. •Uncertainty in an isomerization reaction and a gene regulation network was modelled. •Effects were significant and dependent on the uncertain input and reaction system. •The model was computationally more efficient than Kinetic Monte Carlo.

  13. Substructure System Identification for Finite Element Model Updating

    NASA Technical Reports Server (NTRS)

    Craig, Roy R., Jr.; Blades, Eric L.

    1997-01-01

    This report summarizes research conducted under a NASA grant on the topic 'Substructure System Identification for Finite Element Model Updating.' The research concerns ongoing development of the Substructure System Identification Algorithm (SSID Algorithm), a system identification algorithm that can be used to obtain mathematical models of substructures, like Space Shuttle payloads. In the present study, particular attention was given to the following topics: making the algorithm robust to noisy test data, extending the algorithm to accept experimental FRF data that covers a broad frequency bandwidth, and developing a test analytical model (TAM) for use in relating test data to reduced-order finite element models.

  14. Models for evaluating the performability of degradable computing systems

    NASA Technical Reports Server (NTRS)

    Wu, L. T.

    1982-01-01

    Recent advances in multiprocessor technology established the need for unified methods to evaluate computing systems performance and reliability. In response to this modeling need, a general modeling framework that permits the modeling, analysis and evaluation of degradable computing systems is considered. Within this framework, several user oriented performance variables are identified and shown to be proper generalizations of the traditional notions of system performance and reliability. Furthermore, a time varying version of the model is developed to generalize the traditional fault tree reliability evaluation methods of phased missions.

  15. Isolated heart models: cardiovascular system studies and technological advances.

    PubMed

    Olejnickova, Veronika; Novakova, Marie; Provaznik, Ivo

    2015-07-01

    Isolated heart model is a relevant tool for cardiovascular system studies. It represents a highly reproducible model for studying broad spectrum of biochemical, physiological, morphological, and pharmaceutical parameters, including analysis of intrinsic heart mechanics, metabolism, and coronary vascular response. Results obtained in this model are under no influence of other organ systems, plasma concentration of hormones or ions and influence of autonomic nervous system. The review describes various isolated heart models, the modes of heart perfusion, and advantages and limitations of various experimental setups. It reports the improvements of perfusion setup according to Langendorff introduced by the authors.

  16. On domain modelling of the service system with its application to enterprise information systems

    NASA Astrophysics Data System (ADS)

    Wang, J. W.; Wang, H. F.; Ding, J. L.; Furuta, K.; Kanno, T.; Ip, W. H.; Zhang, W. J.

    2016-01-01

    Information systems are a kind of service systems and they are throughout every element of a modern industrial and business system, much like blood in our body. Types of information systems are heterogeneous because of extreme uncertainty in changes in modern industrial and business systems. To effectively manage information systems, modelling of the work domain (or domain) of information systems is necessary. In this paper, a domain modelling framework for the service system is proposed and its application to the enterprise information system is outlined. The framework is defined based on application of a general domain modelling tool called function-context-behaviour-principle-state-structure (FCBPSS). The FCBPSS is based on a set of core concepts, namely: function, context, behaviour, principle, state and structure and system decomposition. Different from many other applications of FCBPSS in systems engineering, the FCBPSS is applied to both infrastructure and substance systems, which is novel and effective to modelling of service systems including enterprise information systems. It is to be noted that domain modelling of systems (e.g. enterprise information systems) is a key to integration of heterogeneous systems and to coping with unanticipated situations facing to systems.

  17. Building a generalized distributed system model

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.

    1993-01-01

    The key elements in the 1992-93 period of the project are the following: (1) extensive use of the simulator to implement and test - concurrency control algorithms, interactive user interface, and replica control algorithms; and (2) investigations into the applicability of data and process replication in real-time systems. In the 1993-94 period of the project, we intend to accomplish the following: (1) concentrate on efforts to investigate the effects of data and process replication on hard and soft real-time systems - especially we will concentrate on the impact of semantic-based consistency control schemes on a distributed real-time system in terms of improved reliability, improved availability, better resource utilization, and reduced missed task deadlines; and (2) use the prototype to verify the theoretically predicted performance of locking protocols, etc.

  18. Boechera, a model system for ecological genomics

    PubMed Central

    Rushworth, Catherine A.; Song, Bao-Hua; Lee, Cheng-Ruei; Mitchell-Olds, Thomas

    2011-01-01

    The selection and development of a study system for evolutionary and ecological functional genomics (EEFG) depends on a variety of factors. Here we present the genus Boechera as an exemplary system with which to address ecological and evolutionary questions. Our focus on Boechera is based on several characteristics: 1) native populations in undisturbed habitats where current environments reflect historical conditions over several thousand years; 2) functional genomics benefitting from its close relationship to Arabidopsis thaliana; 3) inbreeding tolerance enabling development of recombinant inbred lines, near-isogenic lines, and positional cloning; 4) interspecific crosses permitting mapping for genetic analysis of speciation; 5) apomixis (asexual reproduction by seeds) in a genetically tractable diploid; and 6) broad geographic distribution in North America, permitting ecological genetics for a large research community. These characteristics, along with the current sequencing of three Boechera species by the Joint Genome Institute, position Boechera as a rapidly advancing system for EEFG studies. PMID:22059452

  19. Development of a GIS Based Dust Dispersion Modeling System.

    SciTech Connect

    Rutz, Frederick C.; Hoopes, Bonnie L.; Crandall, Duard W.; Allwine, K Jerry

    2004-08-12

    With residential areas moving closer to military training sites, the effects upon the environment and neighboring civilians due to dust generated by training exercises has become a growing concern. Under a project supported by the Strategic Environmental Research and Development Program (SERDP) of the Department of Defense, a custom application named DUSTRAN is currently under development that integrates a system of EPA atmospheric dispersion models with the ArcGIS application environment in order to simulate the dust dispersion generated by a planned training maneuver. This integration between modeling system and GIS application allows for the use of real world geospatial data such as terrain, land-use, and domain size as input by the modeling system. Output generated by the modeling system, such as concentration and deposition plumes, can then be displayed upon accurate maps representing the training site. This paper discusses the development of this integration between modeling system and Arc GIS application.

  20. The Model Industrial Technology Systems Project.

    ERIC Educational Resources Information Center

    Bowling Green State Univ., OH.

    This document contains materials used in a model industrial technology program that introduced technology into the curricula of elementary, middle, and high schools in three sites in Ohio: the Central site (coordinated through Ohio State University); the Northeast site (coordinated through Kent State University); and the Northwest site…