System of systems modeling and analysis.
Energy Technology Data Exchange (ETDEWEB)
Campbell, James E.; Anderson, Dennis James; Longsine, Dennis E. (Intera, Inc., Austin, TX); 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.
Distribution system modeling and analysis
Kersting, William H
2002-01-01
For decades, distribution engineers did not have the sophisticated tools developed for analyzing transmission systems-often they had only their instincts. Things have changed, and we now have computer programs that allow engineers to simulate, analyze, and optimize distribution systems. Powerful as these programs are, however, without a real understanding of the operating characteristics of a distribution system, engineers using the programs can easily make serious errors in their designs and operating procedures.Distribution System Modeling and Analysis helps prevent those errors. It gives re
Two sustainable energy system analysis models
DEFF Research Database (Denmark)
Lund, Henrik; Goran Krajacic, Neven Duic; da Graca Carvalho, Maria
2005-01-01
This paper presents a comparative study of two energy system analysis models both designed with the purpose of analysing electricity systems with a substantial share of fluctuating renewable energy.......This paper presents a comparative study of two energy system analysis models both designed with the purpose of analysing electricity systems with a substantial share of fluctuating renewable energy....
Extensions in model-based system analysis
Graham, Matthew R.
2007-01-01
Model-based system analysis techniques provide a means for determining desired system performance prior to actual implementation. In addition to specifying desired performance, model-based analysis techniques require mathematical descriptions that characterize relevant behavior of the system. The developments of this dissertation give ex. tended formulations for control- relevant model estimation as well as model-based analysis conditions for performance requirements specified as frequency do...
Analysis hierarchical model for discrete event systems
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.
Modeling and analysis of stochastic systems
Kulkarni, Vidyadhar G
2011-01-01
Based on the author's more than 25 years of teaching experience, Modeling and Analysis of Stochastic Systems, Second Edition covers the most important classes of stochastic processes used in the modeling of diverse systems, from supply chains and inventory systems to genetics and biological systems. For each class of stochastic process, the text includes its definition, characterization, applications, transient and limiting behavior, first passage times, and cost/reward models. Along with reorganizing the material, this edition revises and adds new exercises and examples. New to the second edi
EXPOSURE ANALYSIS MODELING SYSTEM (EXAMS): USER MANUAL AND SYSTEM DOCUMENTATION
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, ...
Guideliness for system modeling: fault tree [analysis
Energy Technology Data Exchange (ETDEWEB)
Lee, Yoon Hwan; Yang, Joon Eon; Kang, Dae Il; Hwang, Mee Jeong
2004-07-01
This document, the guidelines for system modeling related to Fault Tree Analysis(FTA), is intended to provide the guidelines with the analyzer to construct the fault trees in the level of the capability category II of ASME PRA standard. Especially, they are to provide the essential and basic guidelines and the related contents to be used in support of revising the Ulchin 3 and 4 PSA model for risk monitor within the capability category II of ASME PRA standard. Normally the main objective of system analysis is to assess the reliability of system modeled by Event Tree Analysis (ETA). A variety of analytical techniques can be used for the system analysis, however, FTA method is used in this procedures guide. FTA is the method used for representing the failure logic of plant systems deductively using AND, OR or NOT gates. The fault tree should reflect all possible failure modes that may contribute to the system unavailability. This should include contributions due to the mechanical failures of the components, Common Cause Failures (CCFs), human errors and outages for testing and maintenance. This document identifies and describes the definitions and the general procedures of FTA and the essential and basic guidelines for reving the fault trees. Accordingly, the guidelines for FTA will be capable to guide the FTA to the level of the capability category II of ASME PRA standard.
Energy Systems Modelling Research and Analysis
DEFF Research Database (Denmark)
Møller Andersen, Frits; Alberg Østergaard, Poul
2015-01-01
This editorial introduces the seventh volume of the International Journal of Sustainable Energy Planning and Management. The volume presents part of the outcome of the project Energy Systems Modelling Research and Analysis (ENSYMORA) funded by the Danish Innovation Fund. The project carried out...
Formal Modeling and Analysis of Timed Systems
DEFF Research Database (Denmark)
Larsen, Kim Guldstrand; Niebert, Peter
This book constitutes the thoroughly refereed post-proceedings of the First International Workshop on Formal Modeling and Analysis of Timed Systems, FORMATS 2003, held in Marseille, France in September 2003. The 19 revised full papers presented together with an invited paper and the abstracts...
Energy Systems Modelling Research and Analysis
DEFF Research Database (Denmark)
Møller Andersen, Frits; Alberg Østergaard, Poul
2015-01-01
This editorial introduces the seventh volume of the International Journal of Sustainable Energy Planning and Management. The volume presents part of the outcome of the project Energy Systems Modelling Research and Analysis (ENSYMORA) funded by the Danish Innovation Fund. The project carried out...... by 11 university and industry partners has improved the basis for decision-making within energy planning and energy scenario making by providing new and improved tools and methods for energy systems analyses....
2016-06-01
ENGINEERING METHODOLOGY FOR EMPLOYING ARCHITECTURE IN SYSTEM ANALYSIS: DEVELOPING SIMULATION MODELS USING SYSTEMS MODELING LANGUAGE PRODUCTS TO LINK... ENGINEERING METHODOLOGY FOR EMPLOYING ARCHITECTURE IN SYSTEM ANALYSIS: DEVELOPING SIMULATION MODELS USING SYSTEMS MODELING LANGUAGE PRODUCTS TO LINK...to model-based systems engineering (MBSE) by formally defining an MBSE methodology for employing architecture in system analysis (MEASA) that presents
Network and adaptive system of systems modeling and analysis.
Energy Technology Data Exchange (ETDEWEB)
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.
Structured analysis and modeling of complex systems
Strome, David R.; Dalrymple, Mathieu A.
1992-01-01
The Aircrew Evaluation Sustained Operations Performance (AESOP) facility at Brooks AFB, Texas, combines the realism of an operational environment with the control of a research laboratory. In recent studies we collected extensive data from the Airborne Warning and Control Systems (AWACS) Weapons Directors subjected to high and low workload Defensive Counter Air Scenarios. A critical and complex task in this environment involves committing a friendly fighter against a hostile fighter. Structured Analysis and Design techniques and computer modeling systems were applied to this task as tools for analyzing subject performance and workload. This technology is being transferred to the Man-Systems Division of NASA Johnson Space Center for application to complex mission related tasks, such as manipulating the Shuttle grappler arm.
Modeling and analysis of biomass production systems
Energy Technology Data Exchange (ETDEWEB)
Mishoe, J.W.; Lorber, M.N.; Peart, R.M.; Fluck, R.C.; Jones, J.W.
1984-01-01
BIOMET is an interactive simulation model that is used to analyze specific biomass and methane production systems. The system model is composed of crop growth models, harvesting, transportation, conversion and economic submodels. By use of menus the users can configure the structure and set selected parameters of the system to analyze the effects of variables within the component models. For example, simulations of a water hyacinth system resulted in yields of 63, 48 and 37 mg/ha/year for different harvest schedules. For napier grass, unit methane costs were $3.04, $2.86 and $2.98 for various yields of biomass. 10 references.
MODELING AND ANALYSIS OF REGIONAL BOUNDARY SYSTEM
Institute of Scientific and Technical Information of China (English)
YAN Guangle; WANG Huanchen
2001-01-01
In this paper, the problems of modeling and analyzing the system with change able boundary are researched. First, a kind of expanding system is set up, in which the changeable boundary is dealt with as a regional boundary. Then some relative models are developed to describe the regional boundary system. Next, the transition or the driftage of bifurcation points in the system is discussed. A fascinating case is studied in which two or more than two classes of chaotic attractive points coexist together or exist alternatively in the same system. Lastly, an effective new method of chaos avoidance for the system is put forward.
Model correction factor method for system analysis
DEFF Research Database (Denmark)
Ditlevsen, Ove Dalager; Johannesen, Johannes M.
2000-01-01
The Model Correction Factor Method is an intelligent response surface method based on simplifiedmodeling. MCFM is aimed for reliability analysis in case of a limit state defined by an elaborate model. Herein it isdemonstrated that the method is applicable for elaborate limit state surfaces on which...... severallocally most central points exist without there being a simple geometric definition of the corresponding failuremodes such as is the case for collapse mechanisms in rigid plastic hinge models for frame structures. Taking as simplifiedidealized model a model of similarity with the elaborate model...... surface than existing in the idealized model....
Quantitative Models and Analysis for Reactive Systems
DEFF Research Database (Denmark)
Thrane, Claus
phones and websites. Acknowledging that now more than ever, systems come in contact with the physical world, we need to revise the way we construct models and verification algorithms, to take into account the behavior of systems in the presence of approximate, or quantitative information, provided...... by the environment in which they are embedded. This thesis studies the semantics and properties of a model-based framework for re- active systems, in which models and specifications are assumed to contain quantifiable information, such as references to time or energy. Our goal is to develop a theory of approximation......, by studying how small changes to our models affect the verification results. A key source of motivation for this work can be found in The Embedded Systems Design Challenge [HS06] posed by Thomas A. Henzinger and Joseph Sifakis. It contains a call for advances in the state-of-the-art of systems verification...
Quantitative Models and Analysis for Reactive Systems
DEFF Research Database (Denmark)
Thrane, Claus
phones and websites. Acknowledging that now more than ever, systems come in contact with the physical world, we need to revise the way we construct models and verification algorithms, to take into account the behavior of systems in the presence of approximate, or quantitative information, provided......, allowing verification procedures to quantify judgements, on how suitable a model is for a given specification — hence mitigating the usual harsh distinction between satisfactory and non-satisfactory system designs. This information, among other things, allows us to evaluate the robustness of our framework......, by studying how small changes to our models affect the verification results. A key source of motivation for this work can be found in The Embedded Systems Design Challenge [HS06] posed by Thomas A. Henzinger and Joseph Sifakis. It contains a call for advances in the state-of-the-art of systems verification...
Models and analysis for distributed systems
Haddad, Serge; Pautet, Laurent; Petrucci, Laure
2013-01-01
Nowadays, distributed systems are increasingly present, for public software applications as well as critical systems. software applications as well as critical systems. This title and Distributed Systems: Design and Algorithms - from the same editors - introduce the underlying concepts, the associated design techniques and the related security issues.The objective of this book is to describe the state of the art of the formal methods for the analysis of distributed systems. Numerous issues remain open and are the topics of major research projects. One current research trend consists of pro
Cognitive Systems Modeling and Analysis of Command and Control Systems
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.
Power system stability modelling, analysis and control
Sallam, Abdelhay A
2015-01-01
This book provides a comprehensive treatment of the subject from both a physical and mathematical perspective and covers a range of topics including modelling, computation of load flow in the transmission grid, stability analysis under both steady-state and disturbed conditions, and appropriate controls to enhance stability.
Analysis of modeling errors in system identification
Hadaegh, F. Y.; Bekey, G. A.
1986-01-01
This paper is concerned with the identification of a system in the presence of several error sources. Following some basic definitions, the notion of 'near-equivalence in probability' is introduced using the concept of near-equivalence between a model and process. Necessary and sufficient conditions for the identifiability of system parameters are given. The effect of structural error on the parameter estimates for both deterministic and stochastic cases are considered.
[Model-based biofuels system analysis: a review].
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.
MODAL ANALYSIS OF QUARTER CAR MODEL SUSPENSION SYSTEM
Viswanath. K. Allamraju *
2016-01-01
Suspension system is very important for comfort driving and travelling of the passengers. Therefore, this study provides a numerical tool for modeling and analyzing of a two degree of freedom quarter car model suspension system. Modal analysis places a vital role in designing the suspension system. In this paper presented the modal analysis of quarter car model suspension system by considering the undamped and damped factors. The modal and vertical equations of motions describing the su...
Digital Avionics Information System (DAIS): Training Requirements Analysis Model (TRAMOD).
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…
Modelling Immune System: Principles, Models,Analysis and Perspectives
Institute of Scientific and Technical Information of China (English)
Xiang-hua Li; Zheng-xuan Wang; Tian-yang Lu; Xiang-jiu Che
2009-01-01
The biological immune system is a complex adaptive system. There are lots of benefits for building the model of the immune system. For biological researchers, they can test some hypotheses about the infection process or simulate the responses of some drugs. For computer researchers, they can build distributed, robust and fault tolerant networks inspired by the functions of the immune system. This paper provides a comprehensive survey of the literatures on modelling the immune system. From the methodology perspective, the paper compares and analyzes the existing approaches and models, and also demonstrates the focusing research effort on the future immune models in the next few years.
The Financial Analysis System: An Integrated Software System for Financial Analysis and Modeling.
Groomer, S. Michael
This paper discusses the Financial Analysis System (FAS), a software system for financial analysis, display, and modeling of the data found in the COMPUSTAT Annual Industrial, Over-the-Counter and Canadian Company files. The educational utility of FAS is also discussed briefly. (Author)
Model correction factor method for system analysis
DEFF Research Database (Denmark)
Ditlevsen, Ove Dalager; Johannesen, Johannes M.
2000-01-01
severallocally most central points exist without there being a simple geometric definition of the corresponding failuremodes such as is the case for collapse mechanisms in rigid plastic hinge models for frame structures. Taking as simplifiedidealized model a model of similarity with the elaborate model...... but with clearly defined failure modes, the MCFM can bestarted from each idealized single mode limit state in turn to identify a locally most central point on the elaborate limitstate surface. Typically this procedure leads to a fewer number of locally most central failure points on the elaboratelimit state...... surface than existing in the idealized model....
SNPSAM - Space Nuclear Power System Analysis Model
El-Genk, Mohamed S.; Seo, Jong T.
The current version of SNPSAM is described, and the results of the integrated thermoeletric SP-100 system performance studies using SNPSAM are reported. The electric power output, conversion efficiency, coolant temperatures, and specific pumping power of the system are calculated as functions of the reactor thermal power and the liquid metal coolant type (Li or NaK-78) during steady state operation. The transient behavior of the system is also discussed.
Application of dimensional analysis in systems modeling and control design
Balaguer, Pedro
2013-01-01
Dimensional analysis is an engineering tool that is widely applied to numerous engineering problems, but has only recently been applied to control theory and problems such as identification and model reduction, robust control, adaptive control, and PID control. Application of Dimensional Analysis in Systems Modeling and Control Design provides an introduction to the fundamentals of dimensional analysis for control engineers, and shows how they can exploit the benefits of the technique to theoretical and practical control problems.
System modeling based measurement error analysis of digital sun sensors
Institute of Scientific and Technical Information of China (English)
WEI; M; insong; XING; Fei; WANG; Geng; YOU; Zheng
2015-01-01
Stringent attitude determination accuracy is required for the development of the advanced space technologies and thus the accuracy improvement of digital sun sensors is necessary.In this paper,we presented a proposal for measurement error analysis of a digital sun sensor.A system modeling including three different error sources was built and employed for system error analysis.Numerical simulations were also conducted to study the measurement error introduced by different sources of error.Based on our model and study,the system errors from different error sources are coupled and the system calibration should be elaborately designed to realize a digital sun sensor with extra-high accuracy.
Computational Modeling, Formal Analysis, and Tools for Systems Biology.
Bartocci, Ezio; Lió, Pietro
2016-01-01
As the amount of biological data in the public domain grows, so does the range of modeling and analysis techniques employed in systems biology. In recent years, a number of theoretical computer science developments have enabled modeling methodology to keep pace. The growing interest in systems biology in executable models and their analysis has necessitated the borrowing of terms and methods from computer science, such as formal analysis, model checking, static analysis, and runtime verification. Here, we discuss the most important and exciting computational methods and tools currently available to systems biologists. We believe that a deeper understanding of the concepts and theory highlighted in this review will produce better software practice, improved investigation of complex biological processes, and even new ideas and better feedback into computer science.
Modelling and analysis of real-time and hybrid systems
Energy Technology Data Exchange (ETDEWEB)
Olivero, A.
1994-09-29
This work deals with the modelling and analysis of real-time and hybrid systems. We first present the timed-graphs as model for the real-time systems and we recall the basic notions of the analysis of real-time systems. We describe the temporal properties on the timed-graphs using TCTL formulas. We consider two methods for property verification: in one hand we study the symbolic model-checking (based on backward analysis) and in the other hand we propose a verification method derived of the construction of the simulation graph (based on forward analysis). Both methods have been implemented within the KRONOS verification tool. Their application for the automatic verification on several real-time systems confirms the practical interest of our approach. In a second part we study the hybrid systems, systems combining discrete components with continuous ones. As in the general case the analysis of this king of systems is not decidable, we identify two sub-classes of hybrid systems and we give a construction based method for the generation of a timed-graph from an element into the sub-classes. We prove that in one case the timed-graph obtained is bi-similar with the considered system and that there exists a simulation in the other case. These relationships allow the application of the described technics on the hybrid systems into the defined sub-classes. (authors). 60 refs., 43 figs., 8 tabs., 2 annexes.
An Effective Distributed Model for Power System Transient Stability Analysis
Directory of Open Access Journals (Sweden)
MUTHU, B. M.
2011-08-01
Full Text Available The modern power systems consist of many interconnected synchronous generators having different inertia constants, connected with large transmission network and ever increasing demand for power exchange. The size of the power system grows exponentially due to increase in power demand. The data required for various power system applications have been stored in different formats in a heterogeneous environment. The power system applications themselves have been developed and deployed in different platforms and language paradigms. Interoperability between power system applications becomes a major issue because of the heterogeneous nature. The main aim of the paper is to develop a generalized distributed model for carrying out power system stability analysis. The more flexible and loosely coupled JAX-RPC model has been developed for representing transient stability analysis in large interconnected power systems. The proposed model includes Pre-Fault, During-Fault, Post-Fault and Swing Curve services which are accessible to the remote power system clients when the system is subjected to large disturbances. A generalized XML based model for data representation has also been proposed for exchanging data in order to enhance the interoperability between legacy power system applications. The performance measure, Round Trip Time (RTT is estimated for different power systems using the proposed JAX-RPC model and compared with the results obtained using traditional client-server and Java RMI models.
Fractional-Order Nonlinear Systems Modeling, Analysis and Simulation
Petráš, Ivo
2011-01-01
"Fractional-Order Nonlinear Systems: Modeling, Analysis and Simulation" presents a study of fractional-order chaotic systems accompanied by Matlab programs for simulating their state space trajectories, which are shown in the illustrations in the book. Description of the chaotic systems is clearly presented and their analysis and numerical solution are done in an easy-to-follow manner. Simulink models for the selected fractional-order systems are also presented. The readers will understand the fundamentals of the fractional calculus, how real dynamical systems can be described using fractional derivatives and fractional differential equations, how such equations can be solved, and how to simulate and explore chaotic systems of fractional order. The book addresses to mathematicians, physicists, engineers, and other scientists interested in chaos phenomena or in fractional-order systems. It can be used in courses on dynamical systems, control theory, and applied mathematics at graduate or postgraduate level. ...
Product Lifecycle Management Architecture: A Model Based Systems Engineering Analysis.
Energy Technology Data Exchange (ETDEWEB)
Noonan, Nicholas James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2015-07-01
This report is an analysis of the Product Lifecycle Management (PLM) program. The analysis is centered on a need statement generated by a Nuclear Weapons (NW) customer. The need statement captured in this report creates an opportunity for the PLM to provide a robust service as a solution. Lifecycles for both the NW and PLM are analyzed using Model Based System Engineering (MBSE).
Understanding earth system models: how Global Sensitivity Analysis can help
Pianosi, Francesca; Wagener, Thorsten
2017-04-01
Computer models are an essential element of earth system sciences, underpinning our understanding of systems functioning and influencing the planning and management of socio-economic-environmental systems. Even when these models represent a relatively low number of physical processes and variables, earth system models can exhibit a complicated behaviour because of the high level of interactions between their simulated variables. As the level of these interactions increases, we quickly lose the ability to anticipate and interpret the model's behaviour and hence the opportunity to check whether the model gives the right response for the right reasons. Moreover, even if internally consistent, an earth system model will always produce uncertain predictions because it is often forced by uncertain inputs (due to measurement errors, pre-processing uncertainties, scarcity of measurements, etc.). Lack of transparency about the scope of validity, limitations and the main sources of uncertainty of earth system models can be a strong limitation to their effective use for both scientific and decision-making purposes. Global Sensitivity Analysis (GSA) is a set of statistical analysis techniques to investigate the complex behaviour of earth system models in a structured, transparent and comprehensive way. In this presentation, we will use a range of examples across earth system sciences (with a focus on hydrology) to demonstrate how GSA is a fundamental element in advancing the construction and use of earth system models, including: verifying the consistency of the model's behaviour with our conceptual understanding of the system functioning; identifying the main sources of output uncertainty so to focus efforts for uncertainty reduction; finding tipping points in forcing inputs that, if crossed, would bring the system to specific conditions we want to avoid.
Model Analysis of Complex Systems Behavior using MADS
Vesselinov, V. V.; O'Malley, D.
2016-12-01
Evaluation of robustness (reliability) of model predictions is challenging for models representing complex system behavior. Frequently in science and engineering applications related to complex systems, several alternative physics models may describe the available data equally well and are physically reasonable based on the available conceptual understanding. However, these alternative models could give very different predictions about the future states of the analyzed system. Furthermore, in the case of complex systems, we often must do modeling with an incomplete understanding of the underlying physical processes and model parameters. The analyses of model predictions representing complex system behavior are particularly challenging when we are quantifying uncertainties of rare events in the model prediction space that can have major consequences (also called "black swans"). These types of analyses are also computationally challenging. Here, we demonstrate the application of a general high-performance computational tool for Model Analysis & Decision Support (MADS; http://mads.lanl.gov) which can be applied to perform analyses using any external physics or systems model. The coupling between MADS and the external model can be performed using different methods. MADS is implemented in Julia, a high-level, high-performance dynamic programming language for technical computing (http://mads.lanl.gov/, https://github.com/madsjulia/Mads.jl, http://mads.readthedocs.org). MADS has been applied to perform analyses for environmental-management and water-energy-food nexus problems. To demonstrate MADS capabilities and functionalities, we analyze a series of synthetic problems consistent with actual real-world problems.
Uncertainty and sensitivity analysis for photovoltaic system modeling.
Energy Technology Data Exchange (ETDEWEB)
Hansen, Clifford W.; Pohl, Andrew Phillip; Jordan, Dirk
2013-12-01
We report an uncertainty and sensitivity analysis for modeling DC energy from photovoltaic systems. We consider two systems, each comprised of a single module using either crystalline silicon or CdTe cells, and located either at Albuquerque, NM, or Golden, CO. Output from a PV system is predicted by a sequence of models. Uncertainty in the output of each model is quantified by empirical distributions of each model's residuals. We sample these distributions to propagate uncertainty through the sequence of models to obtain an empirical distribution for each PV system's output. We considered models that: (1) translate measured global horizontal, direct and global diffuse irradiance to plane-of-array irradiance; (2) estimate effective irradiance from plane-of-array irradiance; (3) predict cell temperature; and (4) estimate DC voltage, current and power. We found that the uncertainty in PV system output to be relatively small, on the order of 1% for daily energy. Four alternative models were considered for the POA irradiance modeling step; we did not find the choice of one of these models to be of great significance. However, we observed that the POA irradiance model introduced a bias of upwards of 5% of daily energy which translates directly to a systematic difference in predicted energy. Sensitivity analyses relate uncertainty in the PV system output to uncertainty arising from each model. We found that the residuals arising from the POA irradiance and the effective irradiance models to be the dominant contributors to residuals for daily energy, for either technology or location considered. This analysis indicates that efforts to reduce the uncertainty in PV system output should focus on improvements to the POA and effective irradiance models.
Traffic Accident, System Model and Cluster Analysis in GIS
Directory of Open Access Journals (Sweden)
Veronika Vlčková
2015-07-01
Full Text Available One of the many often frequented topics as normal journalism, so the professional public, is the problem of traffic accidents. This article illustrates the orientation of considerations to a less known context of accidents, with the help of constructive systems theory and its methods, cluster analysis and geoinformation engineering. Traffic accident is reframing the space-time, and therefore it can be to study with tools of technology of geographic information systems. The application of system approach enabling the formulation of the system model, grabbed by tools of geoinformation engineering and multicriterial and cluster analysis.
Model-Based Dependability Analysis of Physical Systems with Modelica
Directory of Open Access Journals (Sweden)
Andrea Tundis
2017-01-01
Full Text Available Modelica is an innovative, equation-based, and acausal language that allows modeling complex physical systems, which are made of mechanical, electrical, and electrotechnical components, and evaluates their design through simulation techniques. Unfortunately, the increasing complexity and accuracy of such physical systems require new, more powerful, and flexible tools and techniques for evaluating important system properties and, in particular, the dependability ones such as reliability, safety, and maintainability. In this context, the paper describes some extensions of the Modelica language to support the modeling of system requirements and their relationships. Such extensions enable the requirement verification analysis through native constructs in the Modelica language. Furthermore, they allow exporting a Modelica-based system design as a Bayesian Network in order to analyze its dependability by employing a probabilistic approach. The proposal is exemplified through a case study concerning the dependability analysis of a Tank System.
Failure Propagation Modeling and Analysis via System Interfaces
Directory of Open Access Journals (Sweden)
Lin Zhao
2016-01-01
Full Text Available Safety-critical systems must be shown to be acceptably safe to deploy and use in their operational environment. One of the key concerns of developing safety-critical systems is to understand how the system behaves in the presence of failures, regardless of whether that failure is triggered by the external environment or caused by internal errors. Safety assessment at the early stages of system development involves analysis of potential failures and their consequences. Increasingly, for complex systems, model-based safety assessment is becoming more widely used. In this paper we propose an approach for safety analysis based on system interface models. By extending interaction models on the system interface level with failure modes as well as relevant portions of the physical system to be controlled, automated support could be provided for much of the failure analysis. We focus on fault modeling and on how to compute minimal cut sets. Particularly, we explore state space reconstruction strategy and bounded searching technique to reduce the number of states that need to be analyzed, which remarkably improves the efficiency of cut sets searching algorithm.
Probabilistic Analysis Techniques Applied to Complex Spacecraft Power System Modeling
Hojnicki, Jeffrey S.; Rusick, Jeffrey J.
2005-01-01
Electric power system performance predictions are critical to spacecraft, such as the International Space Station (ISS), to ensure that sufficient power is available to support all the spacecraft s power needs. In the case of the ISS power system, analyses to date have been deterministic, meaning that each analysis produces a single-valued result for power capability because of the complexity and large size of the model. As a result, the deterministic ISS analyses did not account for the sensitivity of the power capability to uncertainties in model input variables. Over the last 10 years, the NASA Glenn Research Center has developed advanced, computationally fast, probabilistic analysis techniques and successfully applied them to large (thousands of nodes) complex structural analysis models. These same techniques were recently applied to large, complex ISS power system models. This new application enables probabilistic power analyses that account for input uncertainties and produce results that include variations caused by these uncertainties. Specifically, N&R Engineering, under contract to NASA, integrated these advanced probabilistic techniques with Glenn s internationally recognized ISS power system model, System Power Analysis for Capability Evaluation (SPACE).
JSim, an open-source modeling system for data analysis.
Butterworth, Erik; Jardine, Bartholomew E; Raymond, Gary M; Neal, Maxwell L; Bassingthwaighte, James B
2013-01-01
JSim is a simulation system for developing models, designing experiments, and evaluating hypotheses on physiological and pharmacological systems through the testing of model solutions against data. It is designed for interactive, iterative manipulation of the model code, handling of multiple data sets and parameter sets, and for making comparisons among different models running simultaneously or separately. Interactive use is supported by a large collection of graphical user interfaces for model writing and compilation diagnostics, defining input functions, model runs, selection of algorithms solving ordinary and partial differential equations, run-time multidimensional graphics, parameter optimization (8 methods), sensitivity analysis, and Monte Carlo simulation for defining confidence ranges. JSim uses Mathematical Modeling Language (MML) a declarative syntax specifying algebraic and differential equations. Imperative constructs written in other languages (MATLAB, FORTRAN, C++, etc.) are accessed through procedure calls. MML syntax is simple, basically defining the parameters and variables, then writing the equations in a straightforward, easily read and understood mathematical form. This makes JSim good for teaching modeling as well as for model analysis for research. For high throughput applications, JSim can be run as a batch job. JSim can automatically translate models from the repositories for Systems Biology Markup Language (SBML) and CellML models. Stochastic modeling is supported. MML supports assigning physical units to constants and variables and automates checking dimensional balance as the first step in verification testing. Automatic unit scaling follows, e.g. seconds to minutes, if needed. The JSim Project File sets a standard for reproducible modeling analysis: it includes in one file everything for analyzing a set of experiments: the data, the models, the data fitting, and evaluation of parameter confidence ranges. JSim is open source; it
Modeling and Stability Analysis of Wedge Clutch System
Directory of Open Access Journals (Sweden)
Jian Yao
2014-01-01
Full Text Available A wedge clutch with unique features of self-reinforcement and small actuation force was designed. Its self-reinforcement feature, associated with different factors such as the wedge angle and friction coefficient, brings different dynamics and unstable problem with improper parameters. To analyze this system, a complete mathematical model of the actuation system is built, which includes the DC motor, the wedge mechanism, and the actuated clutch pack. By considering several nonlinear factors, such as the slip-stick friction and the contact or not of the clutch plates, the system is piecewise linear. Through the stability analysis of the linearized system in clutch slipping phase, the stable condition of the designed parameters is obtained as α>arctan(μc. The mathematical model of the actuation system is validated by prototype testing. And with the validated model, the system dynamics in both stable and unstable conditions is investigated and discussed in engineering side.
Dynamic Response of Linear Mechanical Systems Modeling, Analysis and Simulation
Angeles, Jorge
2012-01-01
Dynamic Response of Linear Mechanical Systems: Modeling, Analysis and Simulation can be utilized for a variety of courses, including junior and senior-level vibration and linear mechanical analysis courses. The author connects, by means of a rigorous, yet intuitive approach, the theory of vibration with the more general theory of systems. The book features: A seven-step modeling technique that helps structure the rather unstructured process of mechanical-system modeling A system-theoretic approach to deriving the time response of the linear mathematical models of mechanical systems The modal analysis and the time response of two-degree-of-freedom systems—the first step on the long way to the more elaborate study of multi-degree-of-freedom systems—using the Mohr circle Simple, yet powerful simulation algorithms that exploit the linearity of the system for both single- and multi-degree-of-freedom systems Examples and exercises that rely on modern computational toolboxes for both numerical and symbolic compu...
Thermal power system analysis using a generalized network flow model
Energy Technology Data Exchange (ETDEWEB)
Kumar, John Arun [Former Senior Design Engineer, Power System Analysis and Control Group, Bharat Heavy Electricals Limited, New Delhi (India); Chebiyam, Radhakrishna [Former Director, Academic Staff College, JNT University, Hyderabad-72 (India)
2012-07-01
This paper analyzes an Integrated Thermal Power System using a Multiperiod Generalized Network Flow Model. The thermal system analysis is carried out by taking into account the complex dynamics involved in utilizing multiple energy carriers (coal, diesel and natural gas). The model comprises energy source nodes, energy transformation nodes, energy storage nodes, energy demand nodes and their interconnections. The solution to the integrated energy system problem involves the evaluation of energy flows that meet the electricity demand at minimum total cost, while satisfying system constraints. This is illustrated through the India case study using a minimum time-step of one hour. MATLAB based software was developed for carrying out this study. TOMLAB/CPLEX software was utilized for obtaining the optimal solution. The model and the methodology utilized for conducting the study would be of interest to those involved in integrated energy system planning for a country or a region.
Generic modelling framework for economic analysis of battery systems
DEFF Research Database (Denmark)
You, Shi; Rasmussen, Claus Nygaard
2011-01-01
for battery cycle life estimation, since the cycle life plays a central role in the economic analysis of BS. To illustrate the modelling framework, a case study using a Sodium Sulfur Battery (NAS) system with 5-minute regulating service is performed. The economic performances of two dispatch scenarios, a so...
Computer Models for IRIS Control System Transient Analysis
Energy Technology Data Exchange (ETDEWEB)
Gary D. Storrick; Bojan Petrovic; Luca Oriani
2007-01-31
This report presents results of the Westinghouse work performed under Task 3 of this Financial Assistance Award and it satisfies a Level 2 Milestone for the project. Task 3 of the collaborative effort between ORNL, Brazil and Westinghouse for the International Nuclear Energy Research Initiative entitled “Development of Advanced Instrumentation and Control for an Integrated Primary System Reactor” focuses on developing computer models for transient analysis. This report summarizes the work performed under Task 3 on developing control system models. The present state of the IRIS plant design – such as the lack of a detailed secondary system or I&C system designs – makes finalizing models impossible at this time. However, this did not prevent making considerable progress. Westinghouse has several working models in use to further the IRIS design. We expect to continue modifying the models to incorporate the latest design information until the final IRIS unit becomes operational. Section 1.2 outlines the scope of this report. Section 2 describes the approaches we are using for non-safety transient models. It describes the need for non-safety transient analysis and the model characteristics needed to support those analyses. Section 3 presents the RELAP5 model. This is the highest-fidelity model used for benchmark evaluations. However, it is prohibitively slow for routine evaluations and additional lower-fidelity models have been developed. Section 4 discusses the current Matlab/Simulink model. This is a low-fidelity, high-speed model used to quickly evaluate and compare competing control and protection concepts. Section 5 describes the Modelica models developed by POLIMI and Westinghouse. The object-oriented Modelica language provides convenient mechanisms for developing models at several levels of detail. We have used this to develop a high-fidelity model for detailed analyses and a faster-running simplified model to help speed the I&C development process
PSAMM: A Portable System for the Analysis of Metabolic Models.
Directory of Open Access Journals (Sweden)
Jon Lund Steffensen
2016-02-01
Full Text Available The genome-scale models of metabolic networks have been broadly applied in phenotype prediction, evolutionary reconstruction, community functional analysis, and metabolic engineering. Despite the development of tools that support individual steps along the modeling procedure, it is still difficult to associate mathematical simulation results with the annotation and biological interpretation of metabolic models. In order to solve this problem, here we developed a Portable System for the Analysis of Metabolic Models (PSAMM, a new open-source software package that supports the integration of heterogeneous metadata in model annotations and provides a user-friendly interface for the analysis of metabolic models. PSAMM is independent of paid software environments like MATLAB, and all its dependencies are freely available for academic users. Compared to existing tools, PSAMM significantly reduced the running time of constraint-based analysis and enabled flexible settings of simulation parameters using simple one-line commands. The integration of heterogeneous, model-specific annotation information in PSAMM is achieved with a novel format of YAML-based model representation, which has several advantages, such as providing a modular organization of model components and simulation settings, enabling model version tracking, and permitting the integration of multiple simulation problems. PSAMM also includes a number of quality checking procedures to examine stoichiometric balance and to identify blocked reactions. Applying PSAMM to 57 models collected from current literature, we demonstrated how the software can be used for managing and simulating metabolic models. We identified a number of common inconsistencies in existing models and constructed an updated model repository to document the resolution of these inconsistencies.
Time between failures model and failure analysis of CNC system
Institute of Scientific and Technical Information of China (English)
ZHANG Hai-bo; JIA Ya-zhou; ZHOU Guang-wen
2007-01-01
To provide basis for the reliability improvement design of CNC system, the failure data of a type of CNC system in one year are collected under field conditions in workshops. The distribution model parameters of time between failures are estimated by least square method and hypothesis testing is done by d-test method. It is proved that the time between failures of the CNC system follows Weibull distribution and the system has entered into the wear-out failure period. The failure positions and failure causes are analyzed further to indicate the weak subsystems of the CNC system. It can be found that servo unit, electrical system, detecting unit and power supply are principal failure positions and the main failure cause is breakage of components. The corresponding improvement measures are put forward. The paper provides a reference to reliability design and analysis of CNC system for the manufacturer and has great guidance to using and maintaining CNC system for the user.
Information System Development Model: Theories Analysis and Guidelines
Nayan, Norshita Mat; Badioze Zaman, Halimah
Development of information system project is one of the IT projects which have been developed to offer the best facilities for publics. Process of system development will go through its own life cycle and every process must be refined in order to fulfill aims and objectives. Eventhough information system development is always correlate with failure but a few key factors will help the systems to succeed. There are multiple success factors being discussed by other researches in the information system development but failure figure still at the higher side. The main purpose of this research is to discuss processes involved in the development of information system which positively contribute towards its success. Model of information system development which has been developed (PADM Model) consists of four fundamental processes; planning, requirement analysis, design and maintenance. All processes will be monitored by a main process namely quality as the key performance indicator. Quality plays a vital role in assessing the ability of information system developed in order to fulfill users' expectations. Analysis of theory can be used as a guideline and measurement base towards the system with hope that percentage of failure will reduce subsequently.
3D Massive MIMO Systems: Modeling and Performance Analysis
Nadeem, Qurrat-Ul-Ain
2015-07-30
Multiple-input-multiple-output (MIMO) systems of current LTE releases are capable of adaptation in the azimuth only. Recently, the trend is to enhance system performance by exploiting the channel’s degrees of freedom in the elevation, which necessitates the characterization of 3D channels. We present an information-theoretic channel model for MIMO systems that supports the elevation dimension. The model is based on the principle of maximum entropy, which enables us to determine the distribution of the channel matrix consistent with the prior information on the angles. Based on this model, we provide analytical expression for the cumulative density function (CDF) of the mutual information (MI) for systems with a single receive and finite number of transmit antennas in the general signalto- interference-plus-noise-ratio (SINR) regime. The result is extended to systems with finite receive antennas in the low SINR regime. A Gaussian approximation to the asymptotic behavior of MI distribution is derived for the large number of transmit antennas and paths regime. We corroborate our analysis with simulations that study the performance gains realizable through meticulous selection of the transmit antenna downtilt angles, confirming the potential of elevation beamforming to enhance system performance. The results are directly applicable to the analysis of 5G 3D-Massive MIMO-systems.
Wind energy conversion system analysis model (WECSAM) computer program documentation
Energy Technology Data Exchange (ETDEWEB)
Downey, W T; Hendrick, P L
1982-07-01
Described is a computer-based wind energy conversion system analysis model (WECSAM) developed to predict the technical and economic performance of wind energy conversion systems (WECS). The model is written in CDC FORTRAN V. The version described accesses a data base containing wind resource data, application loads, WECS performance characteristics, utility rates, state taxes, and state subsidies for a six state region (Minnesota, Michigan, Wisconsin, Illinois, Ohio, and Indiana). The model is designed for analysis at the county level. The computer model includes a technical performance module and an economic evaluation module. The modules can be run separately or together. The model can be run for any single user-selected county within the region or looped automatically through all counties within the region. In addition, the model has a restart capability that allows the user to modify any data-base value written to a scratch file prior to the technical or economic evaluation. Thus, any user-supplied data for WECS performance, application load, utility rates, or wind resource may be entered into the scratch file to override the default data-base value. After the model and the inputs required from the user and derived from the data base are described, the model output and the various output options that can be exercised by the user are detailed. The general operation is set forth and suggestions are made for efficient modes of operation. Sample listings of various input, output, and data-base files are appended. (LEW)
Modelling of electrical power systems for power flow analysis
Energy Technology Data Exchange (ETDEWEB)
Cogo, Joao Roberto [Escola Federal de Engenharia de Itajuba, MG (Brazil)
1994-12-31
The industry systems in Brazil are responsible for a consumption of over 50% (fifty per cent) of the total electrical power generated: therefore, they are import loads in power flow studies, and their modeling should be as much the best. Usually, in power flow studies, the industry systems are modeled by taking the influence of the power (active and reactive) and of the current on the voltage into account. Since the inducting motors, within the industry systems, represent at least 50% (fifty per cent) of the power consumption, and a large part of them is oversize, it is proposed to represent the industry systems as a function of the characteristic of power on shaft versus voltage into account. Since the induction motors, within the industry systems, represent at least 50% (fifty per cent) of the power consumption, and a large part of them is oversized, it is proposed to represent the industry systems as a function of the characteristics of power on shaft versus voltage for the analysis of power systems, aiming a load flow study. Thereafter, a model of an equivalent motor which has a basis the typical performance curve of an induction motor is present. This model is obtained from empirical parameters, surveyed from a population of over 1000 motors. (author) 3 refs., 1 fig., 4 tabs.
Multiway modeling and analysis in stem cell systems biology
Directory of Open Access Journals (Sweden)
Vandenberg Scott L
2008-07-01
Full Text Available Abstract Background Systems biology refers to multidisciplinary approaches designed to uncover emergent properties of biological systems. Stem cells are an attractive target for this analysis, due to their broad therapeutic potential. A central theme of systems biology is the use of computational modeling to reconstruct complex systems from a wealth of reductionist, molecular data (e.g., gene/protein expression, signal transduction activity, metabolic activity, etc.. A number of deterministic, probabilistic, and statistical learning models are used to understand sophisticated cellular behaviors such as protein expression during cellular differentiation and the activity of signaling networks. However, many of these models are bimodal i.e., they only consider row-column relationships. In contrast, multiway modeling techniques (also known as tensor models can analyze multimodal data, which capture much more information about complex behaviors such as cell differentiation. In particular, tensors can be very powerful tools for modeling the dynamic activity of biological networks over time. Here, we review the application of systems biology to stem cells and illustrate application of tensor analysis to model collagen-induced osteogenic differentiation of human mesenchymal stem cells. Results We applied Tucker1, Tucker3, and Parallel Factor Analysis (PARAFAC models to identify protein/gene expression patterns during extracellular matrix-induced osteogenic differentiation of human mesenchymal stem cells. In one case, we organized our data into a tensor of type protein/gene locus link × gene ontology category × osteogenic stimulant, and found that our cells expressed two distinct, stimulus-dependent sets of functionally related genes as they underwent osteogenic differentiation. In a second case, we organized DNA microarray data in a three-way tensor of gene IDs × osteogenic stimulus × replicates, and found that application of tensile strain to a
Mars Entry Atmospheric Data System Modeling, Calibration, and Error Analysis
Karlgaard, Christopher D.; VanNorman, John; Siemers, Paul M.; Schoenenberger, Mark; Munk, Michelle M.
2014-01-01
The Mars Science Laboratory (MSL) Entry, Descent, and Landing Instrumentation (MEDLI)/Mars Entry Atmospheric Data System (MEADS) project installed seven pressure ports through the MSL Phenolic Impregnated Carbon Ablator (PICA) heatshield to measure heatshield surface pressures during entry. These measured surface pressures are used to generate estimates of atmospheric quantities based on modeled surface pressure distributions. In particular, the quantities to be estimated from the MEADS pressure measurements include the dynamic pressure, angle of attack, and angle of sideslip. This report describes the calibration of the pressure transducers utilized to reconstruct the atmospheric data and associated uncertainty models, pressure modeling and uncertainty analysis, and system performance results. The results indicate that the MEADS pressure measurement system hardware meets the project requirements.
Kleijnen, J.P.C.
1995-01-01
This tutorial discusses what-if analysis and optimization of System Dynamics models. These problems are solved, using the statistical techniques of regression analysis and design of experiments (DOE). These issues are illustrated by applying the statistical techniques to a System Dynamics model for
Introduction to modeling and analysis of stochastic systems
Kulkarni, V G
2011-01-01
This is an introductory-level text on stochastic modeling. It is suited for undergraduate students in engineering, operations research, statistics, mathematics, actuarial science, business management, computer science, and public policy. It employs a large number of examples to teach the students to use stochastic models of real-life systems to predict their performance, and use this analysis to design better systems. The book is devoted to the study of important classes of stochastic processes: discrete and continuous time Markov processes, Poisson processes, renewal and regenerative processes, semi-Markov processes, queueing models, and diffusion processes. The book systematically studies the short-term and the long-term behavior, cost/reward models, and first passage times. All the material is illustrated with many examples, and case studies. The book provides a concise review of probability in the appendix. The book emphasizes numerical answers to the problems. A collection of MATLAB programs to accompany...
Advanced transport systems analysis, modeling, and evaluation of performances
Janić, Milan
2014-01-01
This book provides a systematic analysis, modeling and evaluation of the performance of advanced transport systems. It offers an innovative approach by presenting a multidimensional examination of the performance of advanced transport systems and transport modes, useful for both theoretical and practical purposes. Advanced transport systems for the twenty-first century are characterized by the superiority of one or several of their infrastructural, technical/technological, operational, economic, environmental, social, and policy performances as compared to their conventional counterparts. The advanced transport systems considered include: Bus Rapid Transit (BRT) and Personal Rapid Transit (PRT) systems in urban area(s), electric and fuel cell passenger cars, high speed tilting trains, High Speed Rail (HSR), Trans Rapid Maglev (TRM), Evacuated Tube Transport system (ETT), advanced commercial subsonic and Supersonic Transport Aircraft (STA), conventionally- and Liquid Hydrogen (LH2)-fuelled commercial air trans...
Simulation modelling of fynbos ecosystems: Systems analysis and conceptual models
CSIR Research Space (South Africa)
Kruger, FJ
1985-03-01
Full Text Available This report outlines progress with the development of computer based dynamic simulation models for ecosystems in the fynbos biome. The models are planned to run on a portable desktop computer with 500 kbytes of memory, extended BASIC language...
Development of a gas systems analysis model (GSAM)
Energy Technology Data Exchange (ETDEWEB)
Godec, M.L. [IFC Resources Inc., Fairfax, VA (United States)
1995-04-01
The objectives of developing a Gas Systems Analysis Model (GSAM) are to create a comprehensive, non-proprietary, PC based model of domestic gas industry activity. The system is capable of assessing the impacts of various changes in the natural gas system within North America. The individual and collective impacts due to changes in technology and economic conditions are explicitly modeled in GSAM. Major gas resources are all modeled, including conventional, tight, Devonian Shale, coalbed methane, and low-quality gas sources. The modeling system asseses all key components of the gas industry, including available resources, exploration, drilling, completion, production, and processing practices, both for now and in the future. The model similarly assesses the distribution, storage, and utilization of natural gas in a dynamic market-based analytical structure. GSAM is designed to provide METC managers with a tool to project the impacts of future research, development, and demonstration (RD&D) benefits in order to determine priorities in a rapidly changing, market-driven gas industry.
Fusing Quantitative Requirements Analysis with Model-based Systems Engineering
Cornford, Steven L.; Feather, Martin S.; Heron, Vance A.; Jenkins, J. Steven
2006-01-01
A vision is presented for fusing quantitative requirements analysis with model-based systems engineering. This vision draws upon and combines emergent themes in the engineering milieu. "Requirements engineering" provides means to explicitly represent requirements (both functional and non-functional) as constraints and preferences on acceptable solutions, and emphasizes early-lifecycle review, analysis and verification of design and development plans. "Design by shopping" emphasizes revealing the space of options available from which to choose (without presuming that all selection criteria have previously been elicited), and provides means to make understandable the range of choices and their ramifications. "Model-based engineering" emphasizes the goal of utilizing a formal representation of all aspects of system design, from development through operations, and provides powerful tool suites that support the practical application of these principles. A first step prototype towards this vision is described, embodying the key capabilities. Illustrations, implications, further challenges and opportunities are outlined.
Fusing Quantitative Requirements Analysis with Model-based Systems Engineering
Cornford, Steven L.; Feather, Martin S.; Heron, Vance A.; Jenkins, J. Steven
2006-01-01
A vision is presented for fusing quantitative requirements analysis with model-based systems engineering. This vision draws upon and combines emergent themes in the engineering milieu. "Requirements engineering" provides means to explicitly represent requirements (both functional and non-functional) as constraints and preferences on acceptable solutions, and emphasizes early-lifecycle review, analysis and verification of design and development plans. "Design by shopping" emphasizes revealing the space of options available from which to choose (without presuming that all selection criteria have previously been elicited), and provides means to make understandable the range of choices and their ramifications. "Model-based engineering" emphasizes the goal of utilizing a formal representation of all aspects of system design, from development through operations, and provides powerful tool suites that support the practical application of these principles. A first step prototype towards this vision is described, embodying the key capabilities. Illustrations, implications, further challenges and opportunities are outlined.
Nostradamus 2014 prediction, modeling and analysis of complex systems
Suganthan, Ponnuthurai; Chen, Guanrong; Snasel, Vaclav; Abraham, Ajith; Rössler, Otto
2014-01-01
The prediction of behavior of complex systems, analysis and modeling of its structure is a vitally important problem in engineering, economy and generally in science today. Examples of such systems can be seen in the world around us (including our bodies) and of course in almost every scientific discipline including such “exotic” domains as the earth’s atmosphere, turbulent fluids, economics (exchange rate and stock markets), population growth, physics (control of plasma), information flow in social networks and its dynamics, chemistry and complex networks. To understand such complex dynamics, which often exhibit strange behavior, and to use it in research or industrial applications, it is paramount to create its models. For this purpose there exists a rich spectrum of methods, from classical such as ARMA models or Box Jenkins method to modern ones like evolutionary computation, neural networks, fuzzy logic, geometry, deterministic chaos amongst others. This proceedings book is a collection of accepted ...
Modeling and analysis of DFIG in wind energy conversion system
Directory of Open Access Journals (Sweden)
Omer Elfaki Elbashir, Wang Zezhong, Liu Qihui
2014-01-01
Full Text Available This paper deals with the modeling, analysis, and simulation of a doubly-fed induction generator (DFIG driven by a wind turbine. The grid connected wind energy conversion system (WECS is composed of DFIG and two back to back PWM voltage source converters (VSCs in the rotor circuit. A machine model is derived in an appropriate dq reference frame. The grid voltage oriented vector control is used for the grid side converter (GSC in order to maintain a constant DC bus voltage, while the stator voltage orientated vector control is adopted in the rotor side converter (RSC to control the active and reactive powers.
Generic modelling framework for economic analysis of battery systems
DEFF Research Database (Denmark)
You, Shi; Rasmussen, Claus Nygaard
2011-01-01
Deregulated electricity markets provide opportunities for Battery Systems (BS) to participate in energy arbitrage and ancillary services (regulation, operating reserves, contingency reserves, voltage regulation, power quality etc.). To evaluate the economic viability of BS with different business...... for battery cycle life estimation, since the cycle life plays a central role in the economic analysis of BS. To illustrate the modelling framework, a case study using a Sodium Sulfur Battery (NAS) system with 5-minute regulating service is performed. The economic performances of two dispatch scenarios, a so...
Numerical stability analysis in respiratory control system models
Directory of Open Access Journals (Sweden)
Laszlo E. Kollar
2005-04-01
Full Text Available Stability of the unique equilibrium in two mathematical models (based on chemical balance dynamics of human respiration is examined using numerical methods. Due to the transport delays in the respiratory control system these models are governed by delay differential equations. First, a simplified two-state model with one delay is considered, then a five-state model with four delays (where the application of numerical methods is essential is investigated. In particular, software is developed to perform linearized stability analysis and simulations of the model equations. Furthermore, the Matlab package DDE-BIFTOOL v.~2.00 is employed to carry out numerical bifurcation analysis. Our main goal is to study the effects of transport delays on the stability of the model equations. Critical values of the transport delays (i.e., where Hopf bifurcations occur are determined, and stable periodic solutions are found as the delays pass their critical values. The numerical findings are in good agreement with analytic results obtained earlier for the two-state model.
Stochastic Modeling and Analysis of Power System with Renewable Generation
DEFF Research Database (Denmark)
Chen, Peiyuan
to evaluate year-to-year variation of wind power generation through a sensitivity analysis and to forecast very short-term wind power through a model-based prediction method. The stochastic load model is established on the basis of a seasonal autoregressive moving average (ARMA) process. It is demonstrated...... that such a stochastic model can be used to simulate the effect of load management on the load duration curve. As CHP units are turned on and off by regulating power, CHP generation has discrete output and thus can be modeled by a transition matrix based discrete Markov chain. As the CHP generation has a strong diurnal...... that minimizes the expectation of power losses of a 69-bus distribution system by controlling the power factor of WTs. The optimization is subjected to the probabilistic constraints of bus voltage and line current. The algorithm combines a constrained nonlinear optimization algorithm and a Monte Carlo based PLF...
MODEL AND PERFORMANCE ANALYSIS OF FMT SYSTEM AND ORTHOGONAL FILTERBANKS
Institute of Scientific and Technical Information of China (English)
Xu Xiaorong; Zheng Baoyu; Wang Lei
2009-01-01
An orthogonal multi-carrier modulation-Filtered Multi-Tone (FMT) modulation, is evaluated in this paper. The objective of this paper is to model the FMT system with polyphase filterbank network, design its synthesis/analysis orthogonal filterbanks and analyze their performance. Oversampled and critically sampled cases of FMT system are discussed in detail. Perfect Reconstruction (PR) properties of parallel orthogonal subchannels in the case of critically sampled is derived from filterbank polyphase decomposition. Diverse types of prototype filters which include Infinite Impulse Response (IIR) and Finite Impulse Response (FIR) are designed and analyzed. Performance analysis of orthogonal filterbanks which are implemented by these prototype filters are proposed and compared respectively. Simulation results of FMT orthogonal filterbanks are presented. In the end, the application prospect of FMT is discussed.
Macro-System Model for Hydrogen Energy Systems Analysis in Transportation: Preprint
Energy Technology Data Exchange (ETDEWEB)
Diakov, V.; Ruth, M.; Sa, T. J.; Goldsby, M. E.
2012-06-01
The Hydrogen Macro System Model (MSM) is a simulation tool that links existing and emerging hydrogen-related models to perform rapid, cross-cutting analysis. It allows analysis of the economics, primary energy-source requirements, and emissions of hydrogen production and delivery pathways.
Mantis: Predicting System Performance through Program Analysis and Modeling
Chun, Byung-Gon; Lee, Sangmin; Maniatis, Petros; Naik, Mayur
2010-01-01
We present Mantis, a new framework that automatically predicts program performance with high accuracy. Mantis integrates techniques from programming language and machine learning for performance modeling, and is a radical departure from traditional approaches. Mantis extracts program features, which are information about program execution runs, through program instrumentation. It uses machine learning techniques to select features relevant to performance and creates prediction models as a function of the selected features. Through program analysis, it then generates compact code slices that compute these feature values for prediction. Our evaluation shows that Mantis can achieve more than 93% accuracy with less than 10% training data set, which is a significant improvement over models that are oblivious to program features. The system generates code slices that are cheap to compute feature values.
Theoretical Model and Dynamic Analysis of Soft Yoke Mooring System
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
As a popular solution for mooring an FPSO (Floating Production, Storage and Offloading) permanently in shallow water, the soft yoke mooring system has been widely used in ocean oil production activities in the Bohai Bay of China. In order to simulate the interaction mechanism and conduct dynamic analysis of the soft yoke mooring system, a theoretical model with basic dynamic equations is established. A numerical iteration algorithm based on error estimation is developed to solve the equations and calculate the dynamic response of the mooring system due to FPSO motions. Validation is conducted by wave basin experimentation. It is shown that the numerical simulation takes only a few iteration times and the final errors are small. Furthermore, the calculated results of both the static and dynamic responses agree well with those ones obtained by the model test. It indicates that the efficiency, the precision, the reliability and the validity of the developed numerical algorithm and program are rather good. It is proposed to develop a real-time monitoring system to further monitor the dynamic performance of the FPSO with a soft yoke mooring system under various real sea environments.
Interacting Ghost Dark Energy Model: Dynamical System Analysis
Golchin, Hanif; Ebrahimi, Esmaeil
2016-01-01
We study the impacts of interaction between dark matter and dark energy in the context of ghost dark energy model. Using the dynamical system analysis, we obtain the fixed points of the system for different types of interactions while the universe is filled with radiation, matter (including dark matter and luminous matter) and dark energy components. We consider the stability of the fixed points in details for different cases. In all cases there is an unstable matter dominated epoch and a stable late time dark energy dominated phase. However, we find that adding the linear interaction, the evolution of ghost dark energy model does not contain the radiation dominated epoch in the early times which is a necessary point in any cosmic model. This failure resolved when we add the non-linear interaction to the model. We also find an upper bound for the value of the coupling constant of the interaction between dark matter and dark energy as b < 0.57 . This bound is necessary to have a decelerating and unstable ma...
Stability Analysis of a Reaction-Diffusion System Modeling Atherogenesis
Ibragimov, Akif
2010-01-01
This paper presents a linear, asymptotic stability analysis for a reaction-diffusionconvection system modeling atherogenesis, the initiation of atherosclerosis, as an inflammatory instability. Motivated by the disease paradigm articulated by Ross, atherogenesis is viewed as an inflammatory spiral with a positive feedback loop involving key cellular and chemical species interacting and reacting within the intimal layer of muscular arteries. The inflammatory spiral is initiated as an instability from a healthy state which is defined to be an equilibrium state devoid of certain key inflammatory markers. Disease initiation is studied through a linear, asymptotic stability analysis of a healthy equilibrium state. Various theorems are proved, giving conditions on system parameters guaranteeing stability of the health state, and a general framework is developed for constructing perturbations from a healthy state that exhibit blow-up, which are interpreted as corresponding to disease initiation. The analysis reveals key features that arterial geometry, antioxidant levels, and the source of inflammatory components (through coupled third-kind boundary conditions or through body sources) play in disease initiation. © 2010 Society for Industrial and Applied Mathematics.
Dynamic Model of Kaplan Turbine Regulating System Suitable for Power System Analysis
Directory of Open Access Journals (Sweden)
Jie Zhao
2015-01-01
Full Text Available Accurate modeling of Kaplan turbine regulating system is of great significance for grid security and stability analysis. In this paper, Kaplan turbine regulating system model is divided into the governor system model, the blade control system model, and the turbine and water diversion system model. The Kaplan turbine has its particularity, and the on-cam relationship between the wicket gate opening and the runner blade angle under a certain water head on the whole range was obtained by high-order curve fitting method. Progressively the linearized Kaplan turbine model, improved ideal Kaplan turbine model, and nonlinear Kaplan turbine model were developed. The nonlinear Kaplan turbine model considered the correction function of the blade angle on the turbine power, thereby improving the model simulation accuracy. The model parameters were calculated or obtained by the improved particle swarm optimization (IPSO algorithm. For the blade control system model, the default blade servomotor time constant given by value of one simplified the modeling and experimental work. Further studies combined with measured test data verified the established model accuracy and laid a foundation for further research into the influence of Kaplan turbine connecting to the grid.
Analysis Model for Domestic Hot Water Distribution Systems: Preprint
Energy Technology Data Exchange (ETDEWEB)
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.
Model-Based Analysis of a Windmill Communication System
DEFF Research Database (Denmark)
Tjell, Simon
2006-01-01
This paper presents the experiences obtained from modeling and analyzing a real-world application of distributed embedded computing. The modeling language Coloured Petri Nets (CPN) has been applied to analyze the properties of a communication system in a windmill, which enables a group of embedded...... computers to share a group of variables. A CPN-based model of the system is used to analyze certain real-time properties of the system....
Modeling and Analysis of NGC System using Ptolemy II
Directory of Open Access Journals (Sweden)
Archana Sreekumar
2015-09-01
Full Text Available Model based system design has been used in real time embedded systems for validating and testing during the development lifecycle. Computation models - synchronous dataflow model (SDF and Discrete Event (DE have been used and finite state machine has been integrated with SDF and Discrete Event (DE modeling domains for simulating the functionalities in the system. Here a case study of resource augmented Navigation, Guidance and Control unit of onboard computers in satellite launch vehicle has been selected as a frame work and fault tolerant algorithm has been modeled and simulated with Ptolemy II. Feasibility of the scheduling of the fault tolerant algorithm has been analyzed and dependencies existing between different components and processes in the system have been investigated. The future work consists of modeling original functionality of NGC units inside each state of FSM and can be validated for the correct performance. Non-deterministic communication and clock drifts can be accounted into the model.
Markov Modelling of Fingerprinting Systems for Collision Analysis
Directory of Open Access Journals (Sweden)
Guénolé C. M. Silvestre
2008-03-01
Full Text Available Multimedia fingerprinting, also known as robust or perceptual hashing, aims at representing multimedia signals through compact and perceptually significant descriptors (hash values. In this paper, we examine the probability of collision of a certain general class of robust hashing systems that, in its binary alphabet version, encompasses a number of existing robust audio hashing algorithms. Our analysis relies on modelling the fingerprint (hash symbols by means of Markov chains, which is generally realistic due to the hash synchronization properties usually required in multimedia identification. We provide theoretical expressions of performance, and show that the use of M-ary alphabets is advantageous with respect to binary alphabets. We show how these general expressions explain the performance of Philips fingerprinting, whose probability of collision had only been previously estimated through heuristics.
System Reliability Analysis Capability and Surrogate Model Application in RAVEN
Energy Technology Data Exchange (ETDEWEB)
Rabiti, Cristian; Alfonsi, Andrea; Huang, Dongli; Gleicher, Frederick; Wang, Bei; Adbel-Khalik, Hany S.; Pascucci, Valerio; Smith, Curtis L.
2015-11-01
This report collect the effort performed to improve the reliability analysis capabilities of the RAVEN code and explore new opportunity in the usage of surrogate model by extending the current RAVEN capabilities to multi physics surrogate models and construction of surrogate models for high dimensionality fields.
COMPUTER DATA ANALYSIS AND MODELING: COMPLEX STOCHASTIC DATA AND SYSTEMS
2010-01-01
This collection of papers includes proceedings of the Ninth International Conference “Computer Data Analysis and Modeling: Complex Stochastic Data and Systems” organized by the Belarusian State University and held in September 2010 in Minsk. The papers are devoted to the topical problems: robust and nonparametric data analysis; statistical analysis of time series and forecasting; multivariate data analysis; design of experiments; statistical signal and image processing...
Hall, Laverne
1995-01-01
Modeling of the Multi-mission Image Processing System (MIPS) will be described as an example of the use of a modeling tool to design a distributed system that supports multiple application scenarios. This paper examines: (a) modeling tool selection, capabilities, and operation (namely NETWORK 2.5 by CACl), (b) pointers for building or constructing a model and how the MIPS model was developed, (c) the importance of benchmarking or testing the performance of equipment/subsystems being considered for incorporation the design/architecture, (d) the essential step of model validation and/or calibration using the benchmark results, (e) sample simulation results from the MIPS model, and (f) how modeling and simulation analysis affected the MIPS design process by having a supportive and informative impact.
Groleau, Nicolas; Frainier, Richard; Colombano, Silvano; Hazelton, Lyman; Szolovits, Peter
1993-01-01
This paper describes portions of a novel system called MARIKA (Model Analysis and Revision of Implicit Key Assumptions) to automatically revise a model of the normal human orientation system. The revision is based on analysis of discrepancies between experimental results and computer simulations. The discrepancies are calculated from qualitative analysis of quantitative simulations. The experimental and simulated time series are first discretized in time segments. Each segment is then approximated by linear combinations of simple shapes. The domain theory and knowledge are represented as a constraint network. Incompatibilities detected during constraint propagation within the network yield both parameter and structural model alterations. Interestingly, MARIKA diagnosed a data set from the Massachusetts Eye and Ear Infirmary Vestibular Laboratory as abnormal though the data was tagged as normal. Published results from other laboratories confirmed the finding. These encouraging results could lead to a useful clinical vestibular tool and to a scientific discovery system for space vestibular adaptation.
Model-based analysis of control performance in sewer systems
DEFF Research Database (Denmark)
Mollerup, Ane Høyer; Mauricio Iglesias, Miguel; Johansen, N.B.;
2012-01-01
Design and assessment of control in wastewater systems has to be tackled at all levels, including supervisory and regulatory level. We present here an integrated approach to assessment of control in sewer systems based on modelling and the use of process control tools to assess the controllability...... of the process. A case study of a subcatchment area in Copenhagen (Denmark) is used to illustrate the combined approach in modelling of the system and control assessment....
Integrated dynamic landscape analysis and modeling system (IDLAMS) : installation manual.
Energy Technology Data Exchange (ETDEWEB)
Li, Z.; Majerus, K. A.; Sundell, R. C.; Sydelko, P. J.; Vogt, M. C.
1999-02-24
The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) is a prototype, integrated land management technology developed through a joint effort between Argonne National Laboratory (ANL) and the US Army Corps of Engineers Construction Engineering Research Laboratories (USACERL). Dr. Ronald C. Sundell, Ms. Pamela J. Sydelko, and Ms. Kimberly A. Majerus were the principal investigators (PIs) for this project. Dr. Zhian Li was the primary software developer. Dr. Jeffrey M. Keisler, Mr. Christopher M. Klaus, and Mr. Michael C. Vogt developed the decision analysis component of this project. It was developed with funding support from the Strategic Environmental Research and Development Program (SERDP), a land/environmental stewardship research program with participation from the US Department of Defense (DoD), the US Department of Energy (DOE), and the US Environmental Protection Agency (EPA). IDLAMS predicts land conditions (e.g., vegetation, wildlife habitats, and erosion status) by simulating changes in military land ecosystems for given training intensities and land management practices. It can be used by military land managers to help predict the future ecological condition for a given land use based on land management scenarios of various levels of training intensity. It also can be used as a tool to help land managers compare different land management practices and further determine a set of land management activities and prescriptions that best suit the needs of a specific military installation.
Development of a natural gas systems analysis model (GSAM)
Energy Technology Data Exchange (ETDEWEB)
NONE
1999-10-01
This report provides an overview of the activities to date and schedule for future testing, validation, and authorized enhancements of Natural Gas Systems Analysis Model (GSAM). The goal of this report is to inform DOE managers of progress in model development and to provide a benchmark for ongoing and future research. Section II of the report provides a detailed discussion on the major GSAM development programs performed and completed during the period of performance, July 1, 1998 to September 30, 1999. Key improvements in the new GSAM version are summarized in Section III. Programmer's guides for GSAM main modules were produced to provide detailed descriptions of all major subroutines and main variables of the computer code. General logical flowcharts of the subroutines are also presented in the guides to provide overall picture of interactions between the subroutines. A standard structure of routine explanation is applied in every programmer's guide. The explanation is started with a brief description or main purpose of the routine, lists of input and output files read and created, and lists of invoked/child and calling/parent routines. In some of the guides, interactions between the routine itself and its parent and child routines are presented in the form of graphical flowchart. The explanation is then proceeded with step by step description of computer code in the subroutine where each step delegates a section of related code. Between steps, if a certain section of code needs further explanation, a Note is inserted with relevant explanation.
Aviation System Analysis Capability Air Carrier Investment Model-Cargo
Johnson, Jesse; Santmire, Tara
1999-01-01
The purpose of the Aviation System Analysis Capability (ASAC) Air Cargo Investment Model-Cargo (ACIMC), is to examine the economic effects of technology investment on the air cargo market, particularly the market for new cargo aircraft. To do so, we have built an econometrically based model designed to operate like the ACIM. Two main drivers account for virtually all of the demand: the growth rate of the Gross Domestic Product (GDP) and changes in the fare yield (which is a proxy of the price charged or fare). These differences arise from a combination of the nature of air cargo demand and the peculiarities of the air cargo market. The net effect of these two factors are that sales of new cargo aircraft are much less sensitive to either increases in GDP or changes in the costs of labor, capital, fuel, materials, and energy associated with the production of new cargo aircraft than the sales of new passenger aircraft. This in conjunction with the relatively small size of the cargo aircraft market means technology improvements to the cargo aircraft will do relatively very little to spur increased sales of new cargo aircraft.
Design theoretic analysis of three system modeling frameworks.
Energy Technology Data Exchange (ETDEWEB)
McDonald, Michael James
2007-05-01
This paper analyzes three simulation architectures from the context of modeling scalability to address System of System (SoS) and Complex System problems. The paper first provides an overview of the SoS problem domain and reviews past work in analyzing model and general system complexity issues. It then identifies and explores the issues of vertical and horizontal integration as well as coupling and hierarchical decomposition as the system characteristics and metrics against which the tools are evaluated. In addition, it applies Nam Suh's Axiomatic Design theory as a construct for understanding coupling and its relationship to system feasibility. Next it describes the application of MATLAB, Swarm, and Umbra (three modeling and simulation approaches) to modeling swarms of Unmanned Flying Vehicle (UAV) agents in relation to the chosen characteristics and metrics. Finally, it draws general conclusions for analyzing model architectures that go beyond those analyzed. In particular, it identifies decomposition along phenomena of interaction and modular system composition as enabling features for modeling large heterogeneous complex systems.
Analysis of Vector-Inflation Models Using Dynamical Systems
Rodriguez, Jose F
2015-01-01
We analyze two possible vector-field models using the techniques of dynamical systems. The first model involves a U(1)-vector field and the second a triad of SU(2)-vector fields. Both models include a gauge-fixing term and a power-law potential. A dynamical system is formulated and it is found that one of the critical points, for each model, corresponds to inflation, the origin of these critical points being the respective gauge-fixing terms. The conditions for the existence of an inflationary era which lasts for at least 60 efolds are studied.
A Novel Quantitative Analysis Model for Information System Survivability Based on Conflict Analysis
Institute of Scientific and Technical Information of China (English)
WANG Jian; WANG Huiqiang; ZHAO Guosheng
2007-01-01
This paper describes a novel quantitative analysis model for system survivability based on conflict analysis, which provides a direct-viewing survivable situation. Based on the three-dimensional state space of conflict, each player's efficiency matrix on its credible motion set can be obtained. The player whose desire is the strongest in all initiates the moving and the overall state transition matrix of information system may be achieved. In addition, the process of modeling and stability analysis of conflict can be converted into a Markov analysis process, thus the obtained results with occurring probability of each feasible situation will help the players to quantitatively judge the probability of their pursuing situations in conflict. Compared with the existing methods which are limited to post-explanation of system's survivable situation, the proposed model is relatively suitable for quantitatively analyzing and forecasting the future development situation of system survivability. The experimental results show that the model may be effectively applied to quantitative analysis for survivability. Moreover, there will be a good application prospect in practice.
Vehicle-manipulator systems modeling for simulation, analysis, and control
From, Pal Johan; Pettersen, Kristin Ytterstad
2014-01-01
Furthering the aim of reducing human exposure to hazardous environments, this monograph presents a detailed study of the modeling and control of vehicle-manipulator systems. The text shows how complex interactions can be performed at remote locations using systems that combine the manipulability of robotic manipulators with the ability of mobile robots to locomote over large areas. The first part studies the kinematics and dynamics of rigid bodies and standard robotic manipulators and can be used as an introduction to robotics focussing on robust mathematical modeling. The monograph then moves on to study vehicle-manipulator systems in great detail with emphasis on combining two different configuration spaces in a mathematically sound way. Robustness of these systems is extremely important and Modeling and Control of Vehicle-manipulator Systems effectively represents the dynamic equations using a mathematically robust framework. Several tools from Lie theory and differential geometry are used to obtain glob...
Analysis and modeling of noise in biomedical systems.
Ranjbaran, Mina; Jalaleddini, Kian; Lopez, Diego Guarin; Kearney, Robert E; Galiana, Henrietta L
2013-01-01
Noise characteristics play an important role in evaluating tools developed to study biomedical systems. Despite usual assumptions, noise in biomedical systems is often nonwhite or non-Gaussian. In this paper, we present a method to analyze the noise component of a biomedical system. We demonstrate the effectiveness of the method in the analysis of noise in voluntary ankle torque measured by a torque transducer and eye movements measured by electro-oculography (EOG).
Stochastic modeling of friction force and vibration analysis of a mechanical system using the model
Energy Technology Data Exchange (ETDEWEB)
Kang, Won Seok; Choi, Chan Kyu; Yoo, Hong Hee [Hanyang University, Seoul (Korea, Republic of)
2015-09-15
The squeal noise generated from a disk brake or chatter occurred in a machine tool primarily results from friction-induced vibration. Since friction-induced vibration is usually accompanied by abrasion and lifespan reduction of mechanical parts, it is necessary to develop a reliable analysis model by which friction-induced vibration phenomena can be accurately analyzed. The original Coulomb's friction model or the modified Coulomb friction model employed in most commercial programs employs deterministic friction coefficients. However, observing friction phenomena between two contact surfaces, one may observe that friction coefficients keep changing due to the unevenness of contact surface, temperature, lubrication and humidity. Therefore, in this study, friction coefficients are modeled as random parameters that keep changing during the motion of a mechanical system undergoing friction force. The integrity of the proposed stochastic friction model was validated by comparing the analysis results obtained by the proposed model with experimental results.
Energy Technology Data Exchange (ETDEWEB)
Estrin, G.; Fenchel, R.S.; Razouk, R.R.; Vernon, M.K.
1986-02-01
An environment to support designers in the modeling, analysis and simulation of concurrent systems is described. It is shown how a fully nested structure model supports multilevel design and focuses attention on the interfaces between the modules which serve to encapsulate behavior. Using simple examples the paper indicates how a formal graph model can be used to model behavior in three domains: control flow, data flow, and interpretation. The effectiveness of the explicity environment model in SARA is discussed and the capability to analyze correctness and evaluate performance of a system model are demonstrated. A description of the integral help designed into SARA shows how the designer can be offered consistent use of any new tool introduced to support the design process.
Advances in power system modelling, control and stability analysis
Milano, Federico
2016-01-01
This book describes the variety of new methodologies and technologies that are changing the way modern electric power systems are modelled, simulated and operated. It mixes theoretical aspects with practical considerations, as well as benchmarks test systems and real-world applications.
Reliability modeling and analysis of smart power systems
Karki, Rajesh; Verma, Ajit Kumar
2014-01-01
The volume presents the research work in understanding, modeling and quantifying the risks associated with different ways of implementing smart grid technology in power systems in order to plan and operate a modern power system with an acceptable level of reliability. Power systems throughout the world are undergoing significant changes creating new challenges to system planning and operation in order to provide reliable and efficient use of electrical energy. The appropriate use of smart grid technology is an important drive in mitigating these problems and requires considerable research acti
Formal modelling and analysis of socio-technical systems
DEFF Research Database (Denmark)
2016-01-01
systems are still mostly identified through brainstorming of experts. In this work we discuss several approaches to formalising socio-technical systems and their analysis. Starting from a flow logic-based analysis of the insider threat, we discuss how to include the socio aspects explicitly, and show......Attacks on systems and organisations increasingly exploit human actors, for example through social engineering. This non-technical aspect of attacks complicates their formal treatment and automatic identification. Formalisation of human behaviour is difficult at best, and attacks on socio-technical...... a formalisation that proves properties of this formalisation. On the formal side, our work closes the gap between formal and informal approaches to socio-technical systems. On the informal side, we show how to steal a birthday cake from a bakery by social engineering....
3D Massive MIMO Systems: Channel Modeling and Performance Analysis
Nadeem, Qurrat-Ul-Ain
2015-03-01
Multiple-input-multiple-output (MIMO) systems of current LTE releases are capable of adaptation in the azimuth only. More recently, the trend is to enhance the system performance by exploiting the channel\\'s degrees of freedom in the elevation through the dynamic adaptation of the vertical antenna beam pattern. This necessitates the derivation and characterization of three-dimensional (3D) channels. Over the years, channel models have evolved to address the challenges of wireless communication technologies. In parallel to theoretical studies on channel modeling, many standardized channel models like COST-based models, 3GPP SCM, WINNER, ITU have emerged that act as references for industries and telecommunication companies to assess system-level and link-level performances of advanced signal processing techniques over real-like channels. Given the existing channels are only two dimensional (2D) in nature; a large effort in channel modeling is needed to study the impact of the channel component in the elevation direction. The first part of this work sheds light on the current 3GPP activity around 3D channel modeling and beamforming, an aspect that to our knowledge has not been extensively covered by a research publication. The standardized MIMO channel model is presented, that incorporates both the propagation effects of the environment and the radio effects of the antennas. In order to facilitate future studies on the use of 3D beamforming, the main features of the proposed 3D channel model are discussed. A brief overview of the future 3GPP 3D channel model being outlined for the next generation of wireless networks is also provided. In the subsequent part of this work, we present an information-theoretic channel model for MIMO systems that supports the elevation dimension. The model is based on the principle of maximum entropy, which enables us to determine the distribution of the channel matrix consistent with the prior information on the angles of departure and
Modeling, analysis, and design of Networked Control Systems using jump linear systems
Energy Technology Data Exchange (ETDEWEB)
Blind, R.; Muenz, U.; Allgoewer, F. [Stuttgart Univ. (Germany). Inst. fuer Systemtheorie und Regelungstechnik
2008-07-01
Based on recent results from the literature, we give an introduction on modeling, analysis, and design of networked control systems (NCS) using a jump linear system (JLS) formulation. In particular, we consider linear, discrete-time models with a packet-switched communication channel between the sensors and the controller. We assume that the packet-delay and drop-out in the channel can be modeled with independent, identically distributed random processes or Markov chains. With this assumption, we reformulate the problem as a jump system and present both stability conditions and three different controller design algorithms. These results are taken from the literature except for one controller design procedure which is new and has the advantage of giving a fast solution at the expense of higher conservatism. Finally, all design algorithms are illustrated and compared, based on a common simulation example. (orig.)
Modeling and analysis of linear hyperbolic systems of balance laws
Bartecki, Krzysztof
2016-01-01
This monograph focuses on the mathematical modeling of distributed parameter systems in which mass/energy transport or wave propagation phenomena occur and which are described by partial differential equations of hyperbolic type. The case of linear (or linearized) 2 x 2 hyperbolic systems of balance laws is considered, i.e., systems described by two coupled linear partial differential equations with two variables representing physical quantities, depending on both time and one-dimensional spatial variable. Based on practical examples of a double-pipe heat exchanger and a transportation pipeline, two typical configurations of boundary input signals are analyzed: collocated, wherein both signals affect the system at the same spatial point, and anti-collocated, in which the input signals are applied to the two different end points of the system. The results of this book emerge from the practical experience of the author gained during his studies conducted in the experimental installation of a heat exchange cente...
Analysis of Intelligent Transportation Systems Using Model-Driven Simulations
Directory of Open Access Journals (Sweden)
Alberto Fernández-Isabel
2015-06-01
Full Text Available Intelligent Transportation Systems (ITSs integrate information, sensor, control, and communication technologies to provide transport related services. Their users range from everyday commuters to policy makers and urban planners. Given the complexity of these systems and their environment, their study in real settings is frequently unfeasible. Simulations help to address this problem, but present their own issues: there can be unintended mistakes in the transition from models to code; their platforms frequently bias modeling; and it is difficult to compare works that use different models and tools. In order to overcome these problems, this paper proposes a framework for a model-driven development of these simulations. It is based on a specific modeling language that supports the integrated specification of the multiple facets of an ITS: people, their vehicles, and the external environment; and a network of sensors and actuators conveniently arranged and distributed that operates over them. The framework works with a model editor to generate specifications compliant with that language, and a code generator to produce code from them using platform specifications. There are also guidelines to help researchers in the application of this infrastructure. A case study on advanced management of traffic lights with cameras illustrates its use.
Analysis of Intelligent Transportation Systems Using Model-Driven Simulations
Fernández-Isabel, Alberto; Fuentes-Fernández, Rubén
2015-01-01
Intelligent Transportation Systems (ITSs) integrate information, sensor, control, and communication technologies to provide transport related services. Their users range from everyday commuters to policy makers and urban planners. Given the complexity of these systems and their environment, their study in real settings is frequently unfeasible. Simulations help to address this problem, but present their own issues: there can be unintended mistakes in the transition from models to code; their platforms frequently bias modeling; and it is difficult to compare works that use different models and tools. In order to overcome these problems, this paper proposes a framework for a model-driven development of these simulations. It is based on a specific modeling language that supports the integrated specification of the multiple facets of an ITS: people, their vehicles, and the external environment; and a network of sensors and actuators conveniently arranged and distributed that operates over them. The framework works with a model editor to generate specifications compliant with that language, and a code generator to produce code from them using platform specifications. There are also guidelines to help researchers in the application of this infrastructure. A case study on advanced management of traffic lights with cameras illustrates its use. PMID:26083232
Bagdasaryan, Armen
2008-01-01
We present a method of discrete modeling and analysis of multilevel dynamics of complex large-scale hierarchical dynamic systems subject to external dynamic control mechanism. Architectural model of information system supporting simulation and analysis of dynamic processes and development scenarios (strategies) of complex large-scale hierarchical systems is also proposed.
Modeling stock price dynamics by continuum percolation system and relevant complex systems analysis
Xiao, Di; Wang, Jun
2012-10-01
The continuum percolation system is developed to model a random stock price process in this work. Recent empirical research has demonstrated various statistical features of stock price changes, the financial model aiming at understanding price fluctuations needs to define a mechanism for the formation of the price, in an attempt to reproduce and explain this set of empirical facts. The continuum percolation model is usually referred to as a random coverage process or a Boolean model, the local interaction or influence among traders is constructed by the continuum percolation, and a cluster of continuum percolation is applied to define the cluster of traders sharing the same opinion about the market. We investigate and analyze the statistical behaviors of normalized returns of the price model by some analysis methods, including power-law tail distribution analysis, chaotic behavior analysis and Zipf analysis. Moreover, we consider the daily returns of Shanghai Stock Exchange Composite Index from January 1997 to July 2011, and the comparisons of return behaviors between the actual data and the simulation data are exhibited.
Efficient computerized model for dynamic analysis of energy conversion systems
Hughes, R. D.; Lansing, F. L.; Khan, I. R.
1983-02-01
In searching for the optimum parameters that minimize the total life cycle cost of an energy conversion system, various combinations of components are examined and the resulting system performance and associated economics are studied. The systems performance and economics simulation computer program (SPECS) was developed to fill this need. The program simulates the fluid flow, thermal, and electrical characteristics of a system of components on a quasi-steady state basis for a variety of energy conversion systems. A unique approach is used in which the set of characteristic equations is solved by the Newton-Raphson technique. This approach eliminates the tedious iterative loops which are found in comparable programs such as TRNSYS or SOLTES-1. Several efficient features were also incorporated such as the centralized control and energy management scheme, and analogous treatment of energy flow in electrical and mechanical components, and the modeling of components of similar fundamental characteristics using generic subroutines. Initial tests indicate that this model can be used effectively with a relatively small number of time steps and low computer cost.
A Dynamical System Analysis of Three Fluid cosmological Model
Mahata, Nilanjana
2015-01-01
In Friedman-Robertson-Walker flat spacetime, we consider a three fluid cosmological model which contains dark matter, dark energy and baryonic matter in the form of perfect fluid with a barotropic equation of state. Dark matter is taken in form of dust and dark energy is described by a scalar field with a potential $V(\\phi)$. Einstein's field equations are reduced to an autonomous dynamical system by suitable redefinition of basic variables. Considering exponential potential for the scalar field, critical points are obtained for the autonomous system. Finally stability of the critical points and cosmological implications are analyzed.
Analysis of the consequences of aircraft manufacturers’ system integration model
Directory of Open Access Journals (Sweden)
João Henrique Lopes Guerra
2013-11-01
Full Text Available This is a theoretical-conceptual, which aimed to identify some likely consequences of the integration model systems that have been adopted in the aerospace industry by major aircraft manufacturers in the world. In the model of system integration, these manufacturers maintain internally the activities associated with their basic skills and transfer their skills to peripheral suppliers. We identified the following consequences: the growth of strategic alliances in the airline industry, the internationalization of aeronautical chains, with the strengthening of productive activities in some geographic regions; challenges related to the domestic supplier base and the consolidation of national chains, the greatest power suppliers of the first layer, the contribution to the dissemination of knowledge among supply chains, and the potential emergence of new competitors.
Hur, Pilwon; Shorter, K Alex; Mehta, Prashant G; Hsiao-Wecksler, Elizabeth T
2012-04-01
In this paper, a novel analysis technique, invariant density analysis (IDA), is introduced. IDA quantifies steady-state behavior of the postural control system using center of pressure (COP) data collected during quiet standing. IDA relies on the analysis of a reduced-order finite Markov model to characterize stochastic behavior observed during postural sway. Five IDA parameters characterize the model and offer physiological insight into the long-term dynamical behavior of the postural control system. Two studies were performed to demonstrate the efficacy of IDA. Study 1 showed that multiple short trials can be concatenated to create a dataset suitable for IDA. Study 2 demonstrated that IDA was effective at distinguishing age-related differences in postural control behavior between young, middle-aged, and older adults. These results suggest that the postural control system of young adults converges more quickly to their steady-state behavior while maintaining COP nearer an overall centroid than either the middle-aged or older adults. Additionally, larger entropy values for older adults indicate that their COP follows a more stochastic path, while smaller entropy values for young adults indicate a more deterministic path. These results illustrate the potential of IDA as a quantitative tool for the assessment of the quiet-standing postural control system.
REPLACEMENT ANALYSIS FOR DEFECTED PRODUCTS: A SYSTEM DYNAMIC MODELING APPROACH
Directory of Open Access Journals (Sweden)
R. N. Mall
2012-07-01
Full Text Available The current growth in present time due to globalization of markets means more competition for companies especially those in developing economies that have limited analytical tools for business decisions. Market demand uncertainty affects the performance and behavior of the planning processes used by production to satisfy sales. This uncertainty and the resulting instability in the production schedules affect the relationships with the suppliers from whom the company purchases raw materials and component parts. In order to solve the problem, this research developed a SCM system dynamics model that helps business managers and researchers in SCM make better and informed decisions for close life cycle products. The work is focused on the study of behavior of replacement in a supply chain related to closed life-cycle products by system dynamics, that are goods produced and sold and if any defect is found the product is replaced. This study includes the effect of replacement in profit and other variables. This work also includes the development of a model in the system and validation of the model. In this model the relation of the variables like customer, demand, cost, price is studied and the work is focused that what will be the optimum value of the defected product. It has been assumed that if we want to decrease the defected product the cost of the production will increase and that will reduce the profit and if we want to increase the defect the no of customers will decrease and their demand will decrease and this will decrease the profit.
Directory of Open Access Journals (Sweden)
Baiq Nensi Veni Indipenrian
2015-12-01
Full Text Available This study aims to examine the effect of individual behavioral change on the adoption of activity- based costing (ABC system and its usage, using Unified Theory of Accep-tance and Use of Technology (UTAUT and Information System Success Model. The sample involves 78 respondents who have positions as financial manager, controller manager, accounting manager, and production manager in mid-sized manufacturing companies in East java. The data were collected by survey method. This study used a Partial Least Square (PLS as the data analysis method. It was found that not all of the main UTAUT models were supported, because performance expectancy and effort expectancy have no effect on behavioral intention and use behavior to adopt ABC system. Whereas, social factors, information quality and facilitating conditions had a positive effect on behavioral intention and use behavior to adopt ABC system. The different results of this study with several previous studies are probably caused by the differences in the context of system, culture and characteristics of the sample. The implication of this study is not only to propose a theoretical framework for researches in future, but also useful for companies to optimize the use of ABC system that should be supported by top level and mid-level management and the readiness of the individu-als to accept the adoption of the ABC system.
Nuisance Source Population Modeling for Radiation Detection System Analysis
Energy Technology Data Exchange (ETDEWEB)
Sokkappa, P; Lange, D; Nelson, K; Wheeler, R
2009-10-05
A major challenge facing the prospective deployment of radiation detection systems for homeland security applications is the discrimination of radiological or nuclear 'threat sources' from radioactive, but benign, 'nuisance sources'. Common examples of such nuisance sources include naturally occurring radioactive material (NORM), medical patients who have received radioactive drugs for either diagnostics or treatment, and industrial sources. A sensitive detector that cannot distinguish between 'threat' and 'benign' classes will generate false positives which, if sufficiently frequent, will preclude it from being operationally deployed. In this report, we describe a first-principles physics-based modeling approach that is used to approximate the physical properties and corresponding gamma ray spectral signatures of real nuisance sources. Specific models are proposed for the three nuisance source classes - NORM, medical and industrial. The models can be validated against measured data - that is, energy spectra generated with the model can be compared to actual nuisance source data. We show by example how this is done for NORM and medical sources, using data sets obtained from spectroscopic detector deployments for cargo container screening and urban area traffic screening, respectively. In addition to capturing the range of radioactive signatures of individual nuisance sources, a nuisance source population model must generate sources with a frequency of occurrence consistent with that found in actual movement of goods and people. Measured radiation detection data can indicate these frequencies, but, at present, such data are available only for a very limited set of locations and time periods. In this report, we make more general estimates of frequencies for NORM and medical sources using a range of data sources such as shipping manifests and medical treatment statistics. We also identify potential data sources for industrial
Sustainable Deforestation Evaluation Model and System Dynamics Analysis
Directory of Open Access Journals (Sweden)
Huirong Feng
2014-01-01
Full Text Available The current study used the improved fuzzy analytic hierarchy process to construct a sustainable deforestation development evaluation system and evaluation model, which has refined a diversified system to evaluate the theory of sustainable deforestation development. Leveraging the visual image of the system dynamics causal and power flow diagram, we illustrated here that sustainable forestry development is a complex system that encompasses the interaction and dynamic development of ecology, economy, and society and has reflected the time dynamic effect of sustainable forestry development from the three combined effects. We compared experimental programs to prove the direct and indirect impacts of the ecological, economic, and social effects of the corresponding deforest techniques and fully reflected the importance of developing scientific and rational ecological harvesting and transportation technologies. Experimental and theoretical results illustrated that light cableway skidding is an ecoskidding method that is beneficial for the sustainable development of resources, the environment, the economy, and society and forecasted the broad potential applications of light cableway skidding in timber production technology. Furthermore, we discussed the sustainable development countermeasures of forest ecosystems from the aspects of causality, interaction, and harmony.
Sustainable deforestation evaluation model and system dynamics analysis.
Feng, Huirong; Lim, C W; Chen, Liqun; Zhou, Xinnian; Zhou, Chengjun; Lin, Yi
2014-01-01
The current study used the improved fuzzy analytic hierarchy process to construct a sustainable deforestation development evaluation system and evaluation model, which has refined a diversified system to evaluate the theory of sustainable deforestation development. Leveraging the visual image of the system dynamics causal and power flow diagram, we illustrated here that sustainable forestry development is a complex system that encompasses the interaction and dynamic development of ecology, economy, and society and has reflected the time dynamic effect of sustainable forestry development from the three combined effects. We compared experimental programs to prove the direct and indirect impacts of the ecological, economic, and social effects of the corresponding deforest techniques and fully reflected the importance of developing scientific and rational ecological harvesting and transportation technologies. Experimental and theoretical results illustrated that light cableway skidding is an ecoskidding method that is beneficial for the sustainable development of resources, the environment, the economy, and society and forecasted the broad potential applications of light cableway skidding in timber production technology. Furthermore, we discussed the sustainable development countermeasures of forest ecosystems from the aspects of causality, interaction, and harmony.
Testing and reference model analysis of FTTH system
Feng, Xiancheng; Cui, Wanlong; Chen, Ying
2009-08-01
With rapid development of Internet and broadband access network, the technologies of xDSL, FTTx+LAN , WLAN have more applications, new network service emerges in endless stream, especially the increase of network game, meeting TV, video on demand, etc. FTTH supports all present and future service with enormous bandwidth, including traditional telecommunication service, traditional data service and traditional TV service, and the future digital TV and VOD. With huge bandwidth of FTTH, it wins the final solution of broadband network, becomes the final goal of development of optical access network.. Fiber to the Home (FTTH) will be the goal of telecommunications cable broadband access. In accordance with the development trend of telecommunication services, to enhance the capacity of integrated access network, to achieve triple-play (voice, data, image), based on the existing optical Fiber to the curb (FTTC), Fiber To The Zone (FTTZ), Fiber to the Building (FTTB) user optical cable network, the optical fiber can extend to the FTTH system of end-user by using EPON technology. The article first introduced the basic components of FTTH system; and then explain the reference model and reference point for testing of the FTTH system; Finally, by testing connection diagram, the testing process, expected results, primarily analyze SNI Interface Testing, PON interface testing, Ethernet performance testing, UNI interface testing, Ethernet functional testing, PON functional testing, equipment functional testing, telephone functional testing, operational support capability testing and so on testing of FTTH system. ...
ADAM: Analysis of Discrete Models of Biological Systems Using Computer Algebra
Hinkelmann, Franziska; Guang, Bonny; McNeill, Rustin; Blekherman, Grigoriy; Veliz-Cuba, Alan; Laubenbacher, Reinhard
2010-01-01
Motivation: Many biological systems are modeled qualitatively with discrete models, such as probabilistic Boolean networks, logical models, bounded Petri nets, and agent-based models. Simulation is a common practice for analyzing discrete models, but many systems are far too large to capture all the relevant dynamical features through simulation alone. Results: We convert discrete models into algebraic models and apply tools from computational algebra to analyze their dynamics. The key feature of biological systems that is exploited by our algorithms is their sparsity: while the number of nodes in a biological network may be quite large, each node is affected only by a small number of other nodes. In our experience with models arising in systems biology and random models, this structure leads to fast computations when using algebraic models, and thus efficient analysis. Availability: All algorithms and methods are available in our package Analysis of Dynamic Algebraic Models (ADAM), a user friendly web-interf...
Advanced wavefront measurement and analysis of laser system modeling
Energy Technology Data Exchange (ETDEWEB)
Wolfe, C.R.; Auerback, J.M. [Lawrence Livermore National Lab., CA (United States)
1994-11-15
High spatial resolution measurements of the reflected or transmitted wavefronts of large aperture optical components used in high peak power laser systems is now possible. These measurements are produced by phase shifting interferometry. The wavefront data is in the form of 3-D phase maps that reconstruct the wavefront shape. The emphasis of this work is on the characterization of wavefront features in the mid-spatial wavelength range (from 0.1 to 10.0 mm) and has been accomplished for the first time. Wavefront structure from optical components with spatial wavelengths in this range are of concern because their effects in high peak power laser systems. At high peak power, this phase modulation can convert to large magnitude intensity modulation by non-linear processes. This can lead to optical damage. We have developed software to input the measured phase map data into beam propagation codes in order to model this conversion process. We are analyzing this data to: (1) Characterize the wavefront structure produced by current optical components, (2) Refine our understanding of laser system performance, (3) Develop a database from which future optical component specifications can be derived.
MODELING AND ANALYSIS OF ENERGY SYSTEM BASED ON COMPLEX ADAPTIVE SYSTEM
Institute of Scientific and Technical Information of China (English)
QIU Shiming; GU Peiliang
2004-01-01
Complex adaptive system (CAS) is a kind of complex system in natural and artificial systems. In this paper, the theory of complex adaptive system is introduced at first. Considering the characteristic of energy system, it can be regarded as a complex adaptive system. After the evolutionary law is analysed, the energy complex system model is established based on CAS and application tool SWARM, which is a simulation software platform. The model differs from the models as well as methods developed before. As an application, China's energy system is simulated with the model established above.China's future total energy demand in the future, energy structure and related in fiuence on environment are presented.
Nee, John G.; Kare, Audhut P.
1987-01-01
Explores several concepts in computer assisted design/computer assisted manufacturing (CAD/CAM). Defines, evaluates, reviews and compares advanced computer-aided geometric modeling and analysis techniques. Presents the results of a survey to establish the capabilities of minicomputer based-systems with the CAD/CAM packages evaluated. (CW)
NGNP Data Management and Analysis System Modeling Capabilities
Energy Technology Data Exchange (ETDEWEB)
Cynthia D. Gentillon
2009-09-01
Projects for the very-high-temperature reactor (VHTR) program provide data in support of Nuclear Regulatory Commission licensing of the VHTR. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high temperature and high fluence environments. In addition, thermal-hydraulic experiments are conducted to validate codes used to assess reactor safety. The VHTR Program has established the NGNP Data Management and Analysis System (NDMAS) to ensure that VHTR data are (1) qualified for use, (2) stored in a readily accessible electronic form, and (3) analyzed to extract useful results. This document focuses on the third NDMAS objective. It describes capabilities for displaying the data in meaningful ways and identifying relationships among the measured quantities that contribute to their understanding.
Bakshi, S; de Lange, EC; Danhof, M; Peletier, LA
2016-01-01
In this tutorial, we introduce basic concepts in dynamical systems analysis, such as phase‐planes, stability, and bifurcation theory, useful for dissecting the behavior of complex and nonlinear models. A precursor‐pool model with positive feedback is used to demonstrate the power of mathematical analysis. This model is nonlinear and exhibits multiple steady states, the stability of which is analyzed. The analysis offers insight into model behavior and suggests useful parameter regions, which simulations alone could not. PMID:27405001
Bakshi, S; de Lange, E C; van der Graaf, P H; Danhof, M; Peletier, L A
2016-07-01
In this tutorial, we introduce basic concepts in dynamical systems analysis, such as phase-planes, stability, and bifurcation theory, useful for dissecting the behavior of complex and nonlinear models. A precursor-pool model with positive feedback is used to demonstrate the power of mathematical analysis. This model is nonlinear and exhibits multiple steady states, the stability of which is analyzed. The analysis offers insight into model behavior and suggests useful parameter regions, which simulations alone could not.
T-MATS Toolbox for the Modeling and Analysis of Thermodynamic Systems
Chapman, Jeffryes W.
2014-01-01
The Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) is a MATLABSimulink (The MathWorks Inc.) plug-in for creating and simulating thermodynamic systems and controls. The package contains generic parameterized components that can be combined with a variable input iterative solver and optimization algorithm to create complex system models, such as gas turbines.
Iskandar, Ismed; Satria Gondokaryono, Yudi
2016-02-01
In reliability theory, the most important problem is to determine the reliability of a complex system from the reliability of its components. The weakness of most reliability theories is that the systems are described and explained as simply functioning or failed. In many real situations, the failures may be from many causes depending upon the age and the environment of the system and its components. Another problem in reliability theory is one of estimating the parameters of the assumed failure models. The estimation may be based on data collected over censored or uncensored life tests. In many reliability problems, the failure data are simply quantitatively inadequate, especially in engineering design and maintenance system. The Bayesian analyses are more beneficial than the classical one in such cases. The Bayesian estimation analyses allow us to combine past knowledge or experience in the form of an apriori distribution with life test data to make inferences of the parameter of interest. In this paper, we have investigated the application of the Bayesian estimation analyses to competing risk systems. The cases are limited to the models with independent causes of failure by using the Weibull distribution as our model. A simulation is conducted for this distribution with the objectives of verifying the models and the estimators and investigating the performance of the estimators for varying sample size. The simulation data are analyzed by using Bayesian and the maximum likelihood analyses. The simulation results show that the change of the true of parameter relatively to another will change the value of standard deviation in an opposite direction. For a perfect information on the prior distribution, the estimation methods of the Bayesian analyses are better than those of the maximum likelihood. The sensitivity analyses show some amount of sensitivity over the shifts of the prior locations. They also show the robustness of the Bayesian analysis within the range
Time series modeling for analysis and control advanced autopilot and monitoring systems
Ohtsu, Kohei; Kitagawa, Genshiro
2015-01-01
This book presents multivariate time series methods for the analysis and optimal control of feedback systems. Although ships’ autopilot systems are considered through the entire book, the methods set forth in this book can be applied to many other complicated, large, or noisy feedback control systems for which it is difficult to derive a model of the entire system based on theory in that subject area. The basic models used in this method are the multivariate autoregressive model with exogenous variables (ARX) model and the radial bases function net-type coefficients ARX model. The noise contribution analysis can then be performed through the estimated autoregressive (AR) model and various types of autopilot systems can be designed through the state–space representation of the models. The marine autopilot systems addressed in this book include optimal controllers for course-keeping motion, rolling reduction controllers with rudder motion, engine governor controllers, noise adaptive autopilots, route-tracki...
ADAM: analysis of discrete models of biological systems using computer algebra.
Hinkelmann, Franziska; Brandon, Madison; Guang, Bonny; McNeill, Rustin; Blekherman, Grigoriy; Veliz-Cuba, Alan; Laubenbacher, Reinhard
2011-07-20
Many biological systems are modeled qualitatively with discrete models, such as probabilistic Boolean networks, logical models, Petri nets, and agent-based models, to gain a better understanding of them. The computational complexity to analyze the complete dynamics of these models grows exponentially in the number of variables, which impedes working with complex models. There exist software tools to analyze discrete models, but they either lack the algorithmic functionality to analyze complex models deterministically or they are inaccessible to many users as they require understanding the underlying algorithm and implementation, do not have a graphical user interface, or are hard to install. Efficient analysis methods that are accessible to modelers and easy to use are needed. We propose a method for efficiently identifying attractors and introduce the web-based tool Analysis of Dynamic Algebraic Models (ADAM), which provides this and other analysis methods for discrete models. ADAM converts several discrete model types automatically into polynomial dynamical systems and analyzes their dynamics using tools from computer algebra. Specifically, we propose a method to identify attractors of a discrete model that is equivalent to solving a system of polynomial equations, a long-studied problem in computer algebra. Based on extensive experimentation with both discrete models arising in systems biology and randomly generated networks, we found that the algebraic algorithms presented in this manuscript are fast for systems with the structure maintained by most biological systems, namely sparseness and robustness. For a large set of published complex discrete models, ADAM identified the attractors in less than one second. Discrete modeling techniques are a useful tool for analyzing complex biological systems and there is a need in the biological community for accessible efficient analysis tools. ADAM provides analysis methods based on mathematical algorithms as a web
Improved Analysis of Earth System Models and Observations using Simple Climate Models
Nadiga, B. T.; Urban, N. M.
2016-12-01
Earth system models (ESM) are the most comprehensive tools we have to study climate change and develop climate projections. However, the computational infrastructure required and the cost incurred in running such ESMs precludes direct use of such models in conjunction with a wide variety of tools that can further our understanding of climate. Here we are referring to tools that range from dynamical systems tools that give insight into underlying flow structure and topology to tools that come from various applied mathematical and statistical techniques and are central to quantifying stability, sensitivity, uncertainty and predictability to machine learning tools that are now being rapidly developed or improved. Our approach to facilitate the use of such models is to analyze output of ESM experiments (cf. CMIP) using a range of simpler models that consider integral balances of important quantities such as mass and/or energy in a Bayesian framework.We highlight the use of this approach in the context of the uptake of heat by the world oceans in the ongoing global warming. Indeed, since in excess of 90% of the anomalous radiative forcing due greenhouse gas emissions is sequestered in the world oceans, the nature of ocean heat uptake crucially determines the surface warming that is realized (cf. climate sensitivity). Nevertheless, ESMs themselves are never run long enough to directly assess climate sensitivity. So, we consider a range of models based on integral balances--balances that have to be realized in all first-principles based models of the climate system including the most detailed state-of-the art climate simulations. The models range from simple models of energy balance to those that consider dynamically important ocean processes such as the conveyor-belt circulation (Meridional Overturning Circulation, MOC), North Atlantic Deep Water (NADW) formation, Antarctic Circumpolar Current (ACC) and eddy mixing. Results from Bayesian analysis of such models using
Reliability analysis of repairable systems using system dynamics modeling and simulation
Srinivasa Rao, M.; Naikan, V. N. A.
2014-07-01
Repairable standby system's study and analysis is an important topic in reliability. Analytical techniques become very complicated and unrealistic especially for modern complex systems. There have been attempts in the literature to evolve more realistic techniques using simulation approach for reliability analysis of systems. This paper proposes a hybrid approach called as Markov system dynamics (MSD) approach which combines the Markov approach with system dynamics simulation approach for reliability analysis and to study the dynamic behavior of systems. This approach will have the advantages of both Markov as well as system dynamics methodologies. The proposed framework is illustrated for a standby system with repair. The results of the simulation when compared with that obtained by traditional Markov analysis clearly validate the MSD approach as an alternative approach for reliability analysis.
Performance Analysis Model of ManufacturingSystem under Collaborative Product Commerce
Institute of Scientific and Technical Information of China (English)
鲁建厦; 竺炯林; 陈勇; 兰秀菊; 叶艳
2004-01-01
Based on an analysis of the relationship between electronic business (EB) and collaborative product commerce (CPC), the conception of CPC is illustrated rigorously. Development and classification of manufacturing systems are summarized. System features and goals on each stage of a manufacturing system are investigated. In particular, goals and feature characteristics of CPC manufacturing system are discussed. A figure of relationship between the feature and goal ofa CPC manufacturing system is given. A model of CPC manufacturing systems based on a set of five elements including goal, feature, topology, view, and process is proposed. Furthermore, four models of 3D function analysis for PFV, PTV, PTG, and PFG are established.
Analysis of Transition of Pension System in an Endogenous Model
Institute of Scientific and Technical Information of China (English)
叶栩青
2004-01-01
In this paper we investigate the possibility of pareto improving social security reforms within a framework of endogenous growth. Belan et al. proposed a transition from a pay-as-you-go(PAYG) pension system to a system of saving-subsidization. We follow this approach and prove that a pareto improving conversion from the PAYG system to a fully funded system is possible and discuss the problem of implementing the transition to the fully funded system.
Energy Technology Data Exchange (ETDEWEB)
Garcia, H.; Madrigal, M. [Programa de Graduados e Investigacion en Ingenieria Electrica, Instituto Tecnologico de Morelia, Morelia (Mexico); Vyakaranam, B.; Rarick, R.; Villaseca, F.E. [Department of Electrical and Computer Engineering, Cleveland State University, OH (United States)
2011-02-15
In this paper a methodology that extends the dynamic harmonic domain (DHD) analysis of large networks is presented. The method combines DHD analysis and discrete companion circuit modeling resulting in a powerful analytic technique called dynamic companion harmonic circuit modeling. It provides for a complete dynamic harmonic analysis of the system while preserving the advantages of discrete companion circuit models. The methodology is illustrated by its application to a three-node power system, where reactive power compensation is achieved using a fixed-capacitor, thyristor-controlled reactor (FC-TCR) and its control system. (author)
Global analysis of viral infection in an archaeal model system
Directory of Open Access Journals (Sweden)
Walid S. Maaty
2012-12-01
Full Text Available The origin and evolutionary relationship of viruses is poorly understood. This makes archaeal virus-host of particular interest because the hosts generally root near the base of phylogenetic trees, while some of the viruses have clear structural similarities to those that infect prokaryotic and eukaryotic cells. Despite the advantageous position for use in evolutionary studies, little is known about archaeal viruses or how they interact with their hosts, compared to viruses of bacteria and eukaryotes. In addition, many archaeal viruses have been isolated from extreme environments and present a unique opportunity for elucidating factors that are important for existence at the extremes.. In this article we focus on virus-host interactions using a proteomics approach to study Sulfolobus Turreted Icosahedral Virus (STIV infection of Sulfolobus solfataricus P2. Using cultures grown from the ATCC cell stock, a single cycle of STIV infection was sampled 6 times over a 72 hr period. More than 700 proteins were identified throughout the course of the experiments. Seventy one host proteins were found to change by nearly two-fold (p<0.05 with 40 becoming more abundant and 31 less abundant. The modulated proteins represent 30 different cell pathways and 14 COG groups. 2D gel analysis showed that changes in post translational modifications were a common feature of the affected proteins. The results from these studies showed that the prokaryotic antiviral adaptive immune system CRISPR associated proteins (CAS proteins were regulated in response to the virus infection. It was found that regulated proteins come from mRNAs with a shorter than average half-life. In addition, activity-based protein profiling (ABPP profiling on 2D gels showed caspase, hydrolase and tyrosine phosphatase enzyme activity labeling at the protein isoform level. Together, this data provides a more detailed global view of archaeal cellular responses to viral infection, demonstrates the
An Uninhabited Aerial System Safety Analysis Model (USAM) Project
National Aeronautics and Space Administration — The National Airspace System (NAS) in the United States will become a complex array of commercial and general aviation aircraft, unmanned aircraft systems, reusable...
Execution platform modeling for system-level architecture performance analysis
Živković, Vladimir Dobrosav
2008-01-01
Today's embedded systems are designed for more complex and more computationally-intensive applications than they were a decade ago. Most if not every embedded system designed today is a sort of parallel computing system - only called differently - a platform. A platform is essentially a heterogeneo
Czuchry, Andrew J.; And Others
This user's guide describes the functions, logical operations and subroutines, input data requirements, and available outputs of the Training Requirements Analysis Model (TRAMOD), a computerized analytical life cycle cost modeling system for use in the early stages of system design. Operable in a stand-alone mode, TRAMOD can be used for the…
Morshed, Monjur; Ingalls, Brian; Ilie, Silvana
2017-01-01
Sensitivity analysis characterizes the dependence of a model's behaviour on system parameters. It is a critical tool in the formulation, characterization, and verification of models of biochemical reaction networks, for which confident estimates of parameter values are often lacking. In this paper, we propose a novel method for sensitivity analysis of discrete stochastic models of biochemical reaction systems whose dynamics occur over a range of timescales. This method combines finite-difference approximations and adaptive tau-leaping strategies to efficiently estimate parametric sensitivities for stiff stochastic biochemical kinetics models, with negligible loss in accuracy compared with previously published approaches. We analyze several models of interest to illustrate the advantages of our method.
Tank waste remediation system simulation analysis retrieval model
Energy Technology Data Exchange (ETDEWEB)
Fordham, R.A.
1996-09-30
The goal of simulation was to test tll(., consequences of assumptions. For the TWRS SIMAN Retrieval Model, l@lie specific assumptions are primarily defined with respect to waste processing arid transfer timing. The model tracks 73 chem1913ical constituents from underground waste tanks to glass; yet, the detailed (@hemistrv and complete set of unit operations of the TWRS process flow sheet are represented only at the level necessary to define the waste processing and transfer logic and to estimate the feed composition for the treatment facilities. Tlierefor(,, the model should net be regarded as a substitute for the TWRS process flow sheet. Pra(!ticallv the model functions as a dyrt(imic extension of the flow sheet model. I I The following sections present the description, assunipt@ions, architecture, arid evalua- tion of the TWRS SIMAN Retrieval Model. Section 2 describes the model in terms of an overview of the processes represented. Section 3 presents the assumptions for the simulation model. Specific assumptions 9.tt(l parameter values used in the model are provided for waste retrieval, pretreatment, low-level waste (LLNN7) immobilization, and high-level waste (HLW) immobilization functions. Section 4 describes the model in terms of its functional architec- rare to d(@fine a basis for a systematic evaluation of the model. Finally, Section 5 documents an independent test and evaluation of the niodel`s performance (i.e., the verification and validation). Additionally, Appendix A gives a complete listing of the tank inventory used. Appendix B documents the verification and validation plan that was used for the (Section 5) evaluation work. A description and listing of all the model variables is given in Appendix C along with a complete source listing.
Analysis and Application of Mechanical System Reliability Model Based on Copula Function
Directory of Open Access Journals (Sweden)
An Hai
2016-10-01
Full Text Available There is complicated correlations in mechanical system. By using the advantages of copula function to solve the related issues, this paper proposes the mechanical system reliability model based on copula function. And makes a detailed research for the serial and parallel mechanical system model and gets their reliability function respectively. Finally, the application research is carried out for serial mechanical system reliability model to prove its validity by example. Using Copula theory to make mechanical system reliability modeling and its expectation, studying the distribution of the random variables (marginal distribution of the mechanical product’ life and associated structure of variables separately, can reduce the difficulty of multivariate probabilistic modeling and analysis to make the modeling and analysis process more clearly.
Modeling and Stability Analysis for Non-linear Network Control System Based on T-S Fuzzy Model
Institute of Scientific and Technical Information of China (English)
ZHANG Hong; FANG Huajing
2007-01-01
Based on the T-S fuzzy model, this paper presents a new model of non-linear network control system with stochastic transfer delay. Sufficient criterion is proposed to guarantee globally asymptotically stability of this two-levels T-S fuzzy model. Also a T-S fuzzy observer of NCS is designed base on this two-levels T-S fuzzy model. All these results present a new approach for networked control system analysis and design.
Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) User's Guide
Chapman, Jeffryes W.; Lavelle, Thomas M.; May, Ryan D.; Litt, Jonathan S.; Guo, Ten-Huei
2014-01-01
The Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) software package is an open source, MATLABSimulink toolbox (plug in) that can be used by industry professionals and academics for the development of thermodynamic and controls simulations.
Interactive analysis and visualization of massive earth system models using VAPOR
Norton, Alan; Clyne, John
2013-04-01
Recent trends in earth system modeling are leading to a dramatic increase in the size of simulation outputs; however current visualization and analysis capabilities do not readily scale with the increased simulation size. VAPOR is a visualization and analysis package that was designed to enable interactive visualization and analysis of these large datasets, using a wavelet-based multiscale data model. VAPOR runs on Mac, Windows and Linux desktops, exploiting the power of modern graphics cards. VAPOR includes several features to facilitate interactive analysis of earth system data, such as built-in support for Python/NumPy scripting, streamlines, particle tracing and geo-referencing. In this presentation the capabilities of VAPOR will be described and applied to various earth system models. We shall show how to use VAPOR to interactively browse and analyze these large datasets, such as the results of the POP ocean model and the WRF-ARW weather model.
Design, modeling, and analysis of a feedstock logistics system.
Judd, Jason D; Sarin, Subhash C; Cundiff, John S
2012-01-01
Given the location of a bio-energy plant for the conversion of biomass to bio-energy, a feedstock logistics system that relies on the use of satellite storage locations (SSLs) for temporary storage and loading of round bales is proposed. Three equipment systems are considered for handling biomass at the SSLs, and they are either placed permanently or are mobile and thereby travel from one SSL to another. A mathematical programming-based approach is utilized to determine SSLs and equipment routes in order to minimize the total cost. The use of a Side-loading Rack System results in average savings of 21.3% over a Densification System while a Rear-loading Rack System is more expensive to operate than either of the other equipment systems. The utilization of mobile equipment results in average savings of 14.8% over the equipment placed permanently. Furthermore, the Densification System is not justifiable for transportation distances less than 81 km. Copyright © 2011 Elsevier Ltd. All rights reserved.
Analysis of the Model Checkers' Input Languages for Modeling Traffic Light Systems
Directory of Open Access Journals (Sweden)
Pathiah A. Samat
2011-01-01
Full Text Available Problem statement: Model checking is an automated verification technique that can be used for verifying properties of a system. A number of model checking systems have been developed over the last few years. However, there is no guideline that is available for selecting the most suitable model checker to be used to model a particular system. Approach: In this study, we compare the use of four model checkers: SMV, SPIN, UPPAAL and PRISM for modeling a distributed control system. In particular, we are looking at the capabilities of the input languages of these model checkers for modeling this type of system. Limitations and differences of their input language are compared and analyses by using a set of questions. Results: The result of the study shows that although the input languages of these model checkers have a lot of similarities, they also have a significant number of differences. The result of the study also shows that one model checker may be more suitable than others for verifying this type of systems Conclusion: User need to choose the right model checker for the problem to be verified.
Planning and control of maintenance systems modelling and analysis
Duffuaa, Salih O
2015-01-01
Analyzing maintenance as an integrated system with objectives, strategies and processes that need to be planned, designed, engineered, and controlled using statistical and optimization techniques, the theme of this book is the strategic holistic system approach for maintenance. This approach enables maintenance decision makers to view maintenance as a provider of a competitive edge not a necessary evil. Encompassing maintenance systems; maintenance strategic and capacity planning, planned and preventive maintenance, work measurements and standards, material (spares) control, maintenance operations and control, planning and scheduling, maintenance quality, training, and others, this book gives readers an understanding of the relevant methodology and how to apply it to real-world problems in industry. Each chapter includes a number exercises and is suitable as a textbook or a reference for a professionals and practitioners whilst being of interest to industrial engineering, mechanical engineering, electrical en...
Model-Driven Safety Analysis of Closed-Loop Medical Systems.
Pajic, Miroslav; Mangharam, Rahul; Sokolsky, Oleg; Arney, David; Goldman, Julian; Lee, Insup
2012-10-26
In modern hospitals, patients are treated using a wide array of medical devices that are increasingly interacting with each other over the network, thus offering a perfect example of a cyber-physical system. We study the safety of a medical device system for the physiologic closed-loop control of drug infusion. The main contribution of the paper is the verification approach for the safety properties of closed-loop medical device systems. We demonstrate, using a case study, that the approach can be applied to a system of clinical importance. Our method combines simulation-based analysis of a detailed model of the system that contains continuous patient dynamics with model checking of a more abstract timed automata model. We show that the relationship between the two models preserves the crucial aspect of the timing behavior that ensures the conservativeness of the safety analysis. We also describe system design that can provide open-loop safety under network failure.
MODELLING AND VIBRATION ANALYSIS OF A ROAD PROFILE MEASURING SYSTEM
Directory of Open Access Journals (Sweden)
C. B. Patel
2010-06-01
Full Text Available During a vehicle development program, load data representing severe customer usage is required. The dilemma faced by a design engineer during the design process is that during the initial stage, only predicted loads estimated from historical targets are available, whereas the actual loads are available only at the fag end of the process. At the same time, changes required, if any, are easier and inexpensive during the initial stages of the design process whereas they are extremely costly in the latter stages of the process. The use of road profiles and vehicle models to predict the load acting on the whole vehicle is currently being researched. This work hinges on the ability to accurately measure road profiles. The objective of the work is to develop an algorithm, using MATLAB Simulink software, to convert the input signals into measured road profile. The algorithm is checked by the MATLAB Simulink 4 degrees of freedom half car model. To make the whole Simulink model more realistic, accelerometer and laser sensor properties are introduced. The present work contains the simulation of the mentioned algorithm with a half car model and studies the results in distance, time, and the frequency domain.
Modelling, analysis and optimisation of energy systems on offshore platforms
DEFF Research Database (Denmark)
Nguyen, Tuong-Van
Nowadays, the offshore production of oil and gas requires on-site processing, which includes operations such as separation, compression and purification. The offshore system undergoes variations of the petroleum production rates over the field life – it is therefore operated far from its nominal ...
Fuzzy cognitive maps outmatch loop analysis in dynamic modeling of ecological systems
Alessandro Ferrarini
2011-01-01
Modeling natural systems is challenging due to their complexity in terms of variables, interactions, and dynamics. Much of this complexity is rooted in the existence of multiple ways through which acting variables affect each other. Besides the simple direct effects, numerous indirect effects emerge in ecological systems. Through an illustrative example, I exemplify here several advantages of fuzzy cognitive maps (FCM) over loop analysis (LA) in dynamic modeling of ecological systems. In addi...
A MODEL OF HETEROGENEOUS DISTRIBUTED SYSTEM FOR FOREIGN EXCHANGE PORTFOLIO ANALYSIS
Dragutin Kermek; Neven Vrček; Tomislav Jakupić
2006-01-01
The paper investigates the design of heterogeneous distributed system for foreign exchange portfolio analysis. The proposed model includes few separated and dislocated but connected parts through distributed mechanisms. Making system distributed brings new perspectives to performance busting where software based load balancer gets very important role. Desired system should spread over multiple, heterogeneous platforms in order to fulfil open platform goal. Building such a model incorporates d...
Modeling, analysis and control of fuel cell hybrid power systems
Suh, Kyung Won
Transient performance is a key characteristic of fuel cells, that is sometimes more critical than efficiency, due to the importance of accepting unpredictable electric loads. To fulfill the transient requirement in vehicle propulsion and portable fuel cell applications, a fuel cell stack is typically coupled with a battery through a DC/DC converter to form a hybrid power system. Although many power management strategies already exist, they all rely on low level controllers that realize the power split. In this dissertation we design controllers that realize various power split strategies by directly manipulating physical actuators (low level commands). We maintain the causality of the electric dynamics (voltage and current) and investigate how the electric architecture affects the hybridization level and the power management. We first establish the performance limitations associated with a stand-alone and power-autonomous fuel cell system that is not supplemented by an additional energy storage and powers all its auxiliary components by itself. Specifically, we examine the transient performance in fuel cell power delivery as it is limited by the air supplied by a compressor driven by the fuel cell itself. The performance limitations arise from the intrinsic coupling in the fluid and electrical domain between the compressor and the fuel cell stack. Feedforward and feedback control strategies are used to demonstrate these limitations analytically and with simulations. Experimental tests on a small commercial fuel cell auxiliary power unit (APU) confirm the dynamics and the identified limitations. The dynamics associated with the integration of a fuel cell system and a DC/DC converter is then investigated. Decentralized and fully centralized (using linear quadratic techniques) controllers are designed to regulate the power system voltage and to prevent fuel cell oxygen starvation. Regulating these two performance variables is a difficult task and requires a compromise
Modelling and performance analysis of a neurostimulation system
2011-01-01
2009 - 2010 The activity of this thesis is devoted to modelling the electromagnetic behaviour of complex biological structures and in particular of nerve cells and the study of nanotechnology applications to these structures for therapeutic, diagnostic and investigative purposes. The 'design' of artificial nanoscale devices is the chance to accurately understand and manipulate the phenomena that occur inside biological structures. Until a few years ago, the most widely accep...
Analysis and Modeling of Transformerless Photovoltaic Inverter Systems
DEFF Research Database (Denmark)
Kerekes, Tamas
demands. This continuously increasing consumption overloads the distribution grids as well as the power stations, therefore having a negative impact on power availability, security and quality. One of the solutions for overcoming this is the grid-connected photovoltaic (PV) system. PV inverter systems can...... panels and pose safety problems. The major task of this research was the investigation and verification of trans-formerless topologies and control strategies to minimize the leakage current of PV inverter topologies in order to comply with the standard requirements and make them safe for human...... of several commercial mono- and multi-crystalline PV panels has been measured, and an appropriate value has been defined for use in the simula-tions. Also, two commercial current sensors that can be used for leakage current measurement, have been tested and the results are presented in Appendix A. A detailed...
Model Based Cyber Security Analysis for Research Reactor Protection System
Energy Technology Data Exchange (ETDEWEB)
Sho, Jinsoo; Rahman, Khalil Ur; Heo, Gyunyoung [Kyung Hee Univ., Yongin (Korea, Republic of); Son, Hanseong [Joongbu Univ., Geumsan (Korea, Republic of)
2013-07-01
The study on the qualitative risk due to cyber-attacks into research reactors was performed using bayesian Network (BN). This was motivated to solve the issues of cyber security raised due to digitalization of instrumentation and control (I and C) system. As a demonstrative example, we chose the reactor protection system (RPS) of research reactors. Two scenarios of cyber-attacks on RPS were analyzed to develop mitigation measures against vulnerabilities. The one is the 'insertion of reactor trip' and the other is the 'scram halt'. The six mitigation measures are developed for five vulnerability for these scenarios by getting the risk information from BN.
Evaluation of the analysis models in the ASTRA nuclear design code system
Energy Technology Data Exchange (ETDEWEB)
Cho, Nam Jin; Park, Chang Jea; Kim, Do Sam; Lee, Kyeong Taek; Kim, Jong Woon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)
2000-11-15
In the field of nuclear reactor design, main practice was the application of the improved design code systems. During the process, a lot of basis and knowledge were accumulated in processing input data, nuclear fuel reload design, production and analysis of design data, et al. However less efforts were done in the analysis of the methodology and in the development or improvement of those code systems. Recently, KEPO Nuclear Fuel Company (KNFC) developed the ASTRA (Advanced Static and Transient Reactor Analyzer) code system for the purpose of nuclear reactor design and analysis. In the code system, two group constants were generated from the CASMO-3 code system. The objective of this research is to analyze the analysis models used in the ASTRA/CASMO-3 code system. This evaluation requires indepth comprehension of the models, which is important so much as the development of the code system itself. Currently, most of the code systems used in domestic Nuclear Power Plant were imported, so it is very difficult to maintain and treat the change of the situation in the system. Therefore, the evaluation of analysis models in the ASTRA nuclear reactor design code system in very important.
System-wide Benchmark Simulation Model for integrated analysis of urban wastewater systems
DEFF Research Database (Denmark)
Saagi, R.; Flores-Alsina, X.; Gernaey, K. V.
(Gernaey et al., 2014). Given the success of BSMs in evaluation of control strategies for WWTPs, it is envisioned to spatially expand the plant-wide BSM to a system-wide tool. A system-wide BSM can then play an important role, not only in the evaluation of integrated control strategies, but also...... in developing a better understanding of the interactions between different components of an UWS. This paper aims at presenting a system-wide benchmark simulation model that includes catchment, sewer network, WWTP and receiving water subsystems. A hypothetical UWS layout is defined and an integrated model......Interactions between different components (sewer, wastewater treatment plant (WWTP) and river) of an urban wastewater system (UWS) are widely recognized (Benedetti et al., 2013). This has resulted in an increasing interest in the modelling of the UWS. System-wide models take into account...
Responsibility Modeling for the Sociotechnical Risk Analysis of Coalitions of Systems
Greenwood, David
2011-01-01
Society is challenging systems engineers by demanding ever more complex and integrated systems. With the rise of cloud computing and systems-of-systems (including cyber-physical systems) we are entering an era where mission critical services and applications will be dependent upon 'coalitions-of-systems'. Coalitions-of-systems (CoS) are a class of system similar to systems-of-systems but they differ in that they interact to further overlapping self-interests rather than an overarching mission. Assessing the sociotechnical risks associated with CoS is an open research question of societal importance as existing risk analysis techniques typically focus on the technical aspects of systems and ignore risks associated with coalition partners reneging on responsibilities or leaving the coalition. We demonstrate that a responsibility modeling based risk analysis approach enables the identification of sociotechnical risks associated with CoS. The approach identifies hazards and associated risks that may arise when re...
Analysis, Modeling and Optimum Design of Solar Domestic Hot Water Systems
DEFF Research Database (Denmark)
Qin, Lin
1999-01-01
This study focus on the analysis, modeling and simulation of solar domestic hot water(DHW) systems. Problems related to the system operation such as input weather data and hot water load conditions are also investigated.In order to investigate the heat loss as part of the total heat load, dynamic...... model of distribution network is developed and simulations are carried out for typical designed circulation type of distribution networks. For dynamic simulation of thermosyphon and drain-back solar DHW systems, thermosyphon loop model and drain-back tank model are put forward. Based on the simulations...
Investigating modularity in the analysis of process algebra models of biochemical systems
Ciocchetta, Federica; Hillston, Jane; 10.4204/EPTCS.19.4
2010-01-01
Compositionality is a key feature of process algebras which is often cited as one of their advantages as a modelling technique. It is certainly true that in biochemical systems, as in many other systems, model construction is made easier in a formalism which allows the problem to be tackled compositionally. In this paper we consider the extent to which the compositional structure which is inherent in process algebra models of biochemical systems can be exploited during model solution. In essence this means using the compositional structure to guide decomposed solution and analysis. Unfortunately the dynamic behaviour of biochemical systems exhibits strong interdependencies between the components of the model making decomposed solution a difficult task. Nevertheless we believe that if such decomposition based on process algebras could be established it would demonstrate substantial benefits for systems biology modelling. In this paper we present our preliminary investigations based on a case study of the phero...
A Simplified Model for Vibration Analysis of Diesel Engine Crankshaft System
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
A spatial finite element model for vibration analysis of crankshaft system was proposed. The crankshaft body was simplified as spatial rigid frame by using beam elements based on Timoshenko beam theory. The main bearings in system were simplified as linear springs and dashpots. The natural frequencies of the crankshaft system of a four in-line cylinder engine were calculated and compared with the analytical and experimental values available in other publications. In order to simulate the motion of operating crankshaft system, the gas forces, rotating masses and reciprocating masses were considered, the crankshaft and main bearings were coupled in a rotating coordinate system, and a dynamic model for vibration analysis of crankshaft system was established. By applying the dynamic model, the influence of the mass and moment of inertia of front pulley on the behavior of crankshaft vibration was investigated.
Modelling and Performance Analysis of a Flexible Manipulator System Using Symbolic Manipulation
Z. Mohamed; Tokhi, M.O.
2001-01-01
This paper presents a symbolic manipulation approach for modelling and performance analysis of a flexible manipulator system using finite element methods. A constrained planar single-link flexible manipulator is considered. A symbolic algorithm characterising the dynamic behaviour of the system is developed using a symbolic language. Using this approach, the system transfer functions are obtained in symbolic forms. Analyses and investigations in terms of system stability, time response to an ...
ADAM: Analysis of Discrete Models of Biological Systems Using Computer Algebra
Directory of Open Access Journals (Sweden)
Blekherman Grigoriy
2011-07-01
Full Text Available Abstract Background Many biological systems are modeled qualitatively with discrete models, such as probabilistic Boolean networks, logical models, Petri nets, and agent-based models, to gain a better understanding of them. The computational complexity to analyze the complete dynamics of these models grows exponentially in the number of variables, which impedes working with complex models. There exist software tools to analyze discrete models, but they either lack the algorithmic functionality to analyze complex models deterministically or they are inaccessible to many users as they require understanding the underlying algorithm and implementation, do not have a graphical user interface, or are hard to install. Efficient analysis methods that are accessible to modelers and easy to use are needed. Results We propose a method for efficiently identifying attractors and introduce the web-based tool Analysis of Dynamic Algebraic Models (ADAM, which provides this and other analysis methods for discrete models. ADAM converts several discrete model types automatically into polynomial dynamical systems and analyzes their dynamics using tools from computer algebra. Specifically, we propose a method to identify attractors of a discrete model that is equivalent to solving a system of polynomial equations, a long-studied problem in computer algebra. Based on extensive experimentation with both discrete models arising in systems biology and randomly generated networks, we found that the algebraic algorithms presented in this manuscript are fast for systems with the structure maintained by most biological systems, namely sparseness and robustness. For a large set of published complex discrete models, ADAM identified the attractors in less than one second. Conclusions Discrete modeling techniques are a useful tool for analyzing complex biological systems and there is a need in the biological community for accessible efficient analysis tools. ADAM provides
Fujimoto, Kenji; Scherpen, Jacquelien M. A.
2010-01-01
This paper discusses balanced realization and model order reduction for both continuous-time and discrete-time general nonlinear systems based on singular value analysis of the corresponding Hankel operators. Singular value analysis clarifies the gain structure of a given nonlinear operator. Here it
Modeling and Analysis of Power Processing Systems (MAPPS). Volume 1: Technical report
Lee, F. C.; Rahman, S.; Carter, R. A.; Wu, C. H.; Yu, Y.; Chang, R.
1980-01-01
Computer aided design and analysis techniques were applied to power processing equipment. Topics covered include: (1) discrete time domain analysis of switching regulators for performance analysis; (2) design optimization of power converters using augmented Lagrangian penalty function technique; (3) investigation of current-injected multiloop controlled switching regulators; and (4) application of optimization for Navy VSTOL energy power system. The generation of the mathematical models and the development and application of computer aided design techniques to solve the different mathematical models are discussed. Recommendations are made for future work that would enhance the application of the computer aided design techniques for power processing systems.
DEFF Research Database (Denmark)
Ruano, MV; Ribes, J; de Pauw, DJW
2007-01-01
In this work we address the issue of parameter subset selection within the scope of activated sludge model calibration. To this end, we evaluate two approaches: (i) systems analysis and (ii) experience-based approach. The evaluation has been carried out using a dynamic model (ASM2d) calibrated...... based approaches which excluded them from their analysis. Systems analysis reveals that parameter significance ranking and size of the identifiable parameter subset depend on the information content of data available for calibration. However, it suffers from heavy computational demand. In contrast...
Ferguson, R. E.
1985-01-01
The data base verification of the ECLS Systems Assessment Program (ESAP) was documented and changes made to enhance the flexibility of the water recovery subsystem simulations are given. All changes which were made to the data base values are described and the software enhancements performed. The refined model documented herein constitutes the submittal of the General Cluster Systems Model. A source listing of the current version of ESAP is provided in Appendix A.
2012-02-03
as ADP amd MPC) to bear upon the immediate acquisition problem, keeping enterprise, model-centric architectures of decision-making processes in...useful in model-centric enterprise systems, where clear visualization of connectivity between individual systems is crucial to the design and...html/proj- constella tion/ltr-rep.pdf [accessed 15 January 2009]. Dekker, T. J., & Hoffmann, W. (1989). Rehabilitation of the Gauss-Jordan Algorithm
Uncertainty modeling in vibration, control and fuzzy analysis of structural systems
Halder, Achintya; Ayyub, Bilal M
1997-01-01
This book gives an overview of the current state of uncertainty modeling in vibration, control, and fuzzy analysis of structural and mechanical systems. It is a coherent compendium written by leading experts and offers the reader a sampling of exciting research areas in several fast-growing branches in this field. Uncertainty modeling and analysis are becoming an integral part of system definition and modeling in many fields. The book consists of ten chapters that report the work of researchers, scientists and engineers on theoretical developments and diversified applications in engineering sy
Modeling and analysis of doubly fed induction generator wind energy systems
Fan, Lingling
2015-01-01
Wind Energy Systems: Modeling, Analysis and Control with DFIG provides key information on machine/converter modelling strategies based on space vectors, complex vector, and further frequency-domain variables. It includes applications that focus on wind energy grid integration, with analysis and control explanations with examples. For those working in the field of wind energy integration examining the potential risk of stability is key, this edition looks at how wind energy is modelled, what kind of control systems are adopted, how it interacts with the grid, as well as suitable study
Institute of Scientific and Technical Information of China (English)
Tan Xiaodong; Qiu Jing; Liu Guanjun; Lv Kehong; Yang Shuming; Wang Chao
2013-01-01
Prognostics and health management (PHM) significantly improves system availability and reliability,and reduces the cost of system operations.Design for testability (DFT) developed concurrently with system design is an important way to improve PHM capability.Testability modeling and analysis are the foundation of DFT.This paper proposes a novel approach of testability modeling and analysis based on failure evolution mechanisms.At the component level,the fault progression-related information of each unit under test (UUT) in a system is obtained by means of failure modes,evolution mechanisms,effects and criticality analysis (FMEMECA),and then the failure-symptom dependency can be generated.At the system level,the dynamic attributes of UUTs are assigned by using the bond graph methodology,and then the symptom-test dependency can be obtained by means of the functional flow method.Based on the failure-symptom and symptom-test dependencies,testability analysis for PHM systems can be realized.A shunt motor is used to verify the application of the approach proposed in this paper.Experimental results show that this approach is able to be applied to testability modeling and analysis for PHM systems very well,and the analysis results can provide a guide for engineers to design for testability in order to improve PHM performance.
Service Oriented Architectural Model for Load Flow Analysis in Power Systems
Muthu, Balasingh Moses; Veilumuthu, Ramachandran; Ponnusamy, Lakshmi
2011-07-01
The main objective of this paper is to develop the Service Oriented Architectural (SOA) Model for representation of power systems, especially of computing load flow analysis of large interconnected power systems. The proposed SOA model has three elements namely load flow service provider, power systems registry and client. The exchange of data using XML makes the power system services standardized and adaptable. The load flow service is provided by the service provider, which is published in power systems registry for enabling universal visibility and access to the service. The message oriented style of SOA using Simple Object Access Protocol (SOAP) makes the service provider and the power systems client to exist in a loosely coupled environment. This proposed model, portraits the load flow services as Web services in service oriented environment. To suit the power system industry needs, it easily integrates with the Web applications which enables faster power system operations.
Restructured electric power systems analysis of electricity markets with equilibrium models
2010-01-01
Electricity market deregulation is driving the power energy production from a monopolistic structure into a competitive market environment. The development of electricity markets has necessitated the need to analyze market behavior and power. Restructured Electric Power Systems reviews the latest developments in electricity market equilibrium models and discusses the application of such models in the practical analysis and assessment of electricity markets.
A critical analysis of the X.400 model of message handling systems
van Sinderen, Marten J.; Dorregeest, Evert
1988-01-01
The CCITT X.400 model of store and forward Message Handling Systems (MHS) serves as a common basis for the definition of electronic mail services and protocols both within CCITT and ISO. This paper presents an analysis of this model and its related recommendations from two perspectives. First the
Seismic analysis of the APR1400 nuclear reactor system using a verified beam element model
Energy Technology Data Exchange (ETDEWEB)
Park, Jong-beom [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Park, No-Cheol, E-mail: pnch@yonsei.ac.kr [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Lee, Sang-Jeong; Park, Young-Pil [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Choi, Youngin [Korea Institute of Nuclear Safety, 62 Gwahak-ro, Yuseong-gu, Daejeon 34142 (Korea, Republic of)
2017-03-15
Highlights: • A simplified beam element model is constructed based on the real dynamic characteristics of the APR1400. • Time history analysis is performed to calculate the seismic responses of the structures. • Large deformations can be observed at the in-phase mode of reactor vessel and core support barrel. - Abstract: Structural integrity is the first priority in the design of nuclear reactor internal structures. In particular, nuclear reactor internals should be designed to endure external forces, such as those due to earthquakes. Many researchers have performed finite element analyses to meet these design requirements. Generally, a seismic analysis model should reflect the dynamic characteristics of the target system. However, seismic analysis based on the finite element method requires long computation times as well as huge storage space. In this research, a beam element model was developed and confirmed based on the real dynamic characteristics of an advanced pressurized water nuclear reactor 1400 (APR1400) system. That verification process enhances the accuracy of the finite element analysis using the beam elements, remarkably. Also, the beam element model reduces seismic analysis costs. Therefore, the beam element model was used to perform the seismic analysis. Then, the safety of the APR1400 was assessed based on a seismic analysis of the time history responses of its structures. Thus, efficient, accurate seismic analysis was demonstrated using the proposed beam element model.
Withag, Jan A.M.; Smeets, Jules R.; Bramer, Eddy A.; Brem, Gerrit
2012-01-01
This article presents a system model for the process of gasification of biomass model compounds in supercritical water. Supercritical water gasification of wet biomass (water content of 70 wt% or more) has as the main advantage that conversion may take place without the costly drying step. The therm
Withag, J.A.M.; Smeets, Jules R.; Bramer, E.A.; Brem, G.
2012-01-01
This article presents a system model for the process of gasification of biomass model compounds in supercritical water. Supercritical water gasification of wet biomass (water content of 70 wt% or more) has as the main advantage that conversion may take place without the costly drying step. The therm
Mitchell, Christine M.
1990-01-01
The design, implementation, and empirical evaluation of task-analytic models and intelligent aids for operators in the control of complex dynamic systems, specifically aerospace systems, are studied. Three related activities are included: (1) the models of operator decision making in complex and predominantly automated space systems were used and developed; (2) the Operator Function Model (OFM) was used to represent operator activities; and (3) Operator Function Model Expert System (OFMspert), a stand-alone knowledge-based system was developed, that interacts with a human operator in a manner similar to a human assistant in the control of aerospace systems. OFMspert is an architecture for an operator's assistant that uses the OFM as its system and operator knowledge base and a blackboard paradigm of problem solving to dynamically generate expectations about upcoming operator activities and interpreting actual operator actions. An experiment validated the OFMspert's intent inferencing capability and showed that it inferred the intentions of operators in ways comparable to both a human expert and operators themselves. OFMspert was also augmented with control capabilities. An interface allowed the operator to interact with OFMspert, delegating as much or as little control responsibility as the operator chose. With its design based on the OFM, OFMspert's control capabilities were available at multiple levels of abstraction and allowed the operator a great deal of discretion over the amount and level of delegated control. An experiment showed that overall system performance was comparable for teams consisting of two human operators versus a human operator and OFMspert team.
Bakshi, S.D.; Lange, de E.C.M.; Graaf, van der P.H.; Danhof, M.; Peletier, L.A.
2016-01-01
In this tutorial, we introduce basic concepts in dynamical systems analysis, such as phase-planes, stability, and bifurcation theory, useful for dissecting the behavior of complex and nonlinear models. A precursor-pool model with positive feedback is used to demonstrate the power of mathematical ana
Bakshi, S.D.; Lange, de E.C.M.; Graaf, van der P.H.; Danhof, M.; Peletier, L.A.
2016-01-01
In this tutorial, we introduce basic concepts in dynamical systems analysis, such as phase-planes, stability, and bifurcation theory, useful for dissecting the behavior of complex and nonlinear models. A precursor-pool model with positive feedback is used to demonstrate the power of mathematical ana
Institute of Scientific and Technical Information of China (English)
LIU Jing-Quan; YOSHIKAWA Hidekazu; ZHOU Yang-Ping
2005-01-01
Complex energy and environment system, especially nuclear fuel cycle system recently raised social concerns about the issues of economic competitiveness, environmental effect and nuclear proliferation. Only under the condition that those conflicting issues are gotten a consensus between stakeholders with different knowledge background, can nuclear power industry be continuingly developed. In this paper, a new analysis platform has been developed to help stakeholders to recognize and analyze various socio-technical issues in the nuclear fuel cycle system based on the functional modeling method named Multilevel Flow Models (MFM) according to the cognition theory of human being. Its character is that MFM models define a set of mass, energy and information flow structures on multiple levels of abstraction to describe the functional structure of a process system and its graphical symbol representation and the means-end and part-whole hierarchical flow structure to make the represented process easy to be understood. Based upon this methodology, a micro-process and a macro-process of nuclear fuel cycle system were selected to be simulated and some analysis processes such as economics analysis, environmental analysis and energy balance analysis related to those flows were also integrated to help stakeholders to understand the process of decision-making with the introduction of some new functions for the improved Multilevel Flow Models Studio, and finally the simple simulation such as spent fuel management process simulation and money flow of nuclear fuel cycle and its levelised cost analysis will be represented as feasible examples.
Inoue, Kentaro; Maeda, Kazuhiro; Miyabe, Takaaki; Matsuoka, Yu; Kurata, Hiroyuki
2014-09-01
Mathematical modeling has become a standard technique to understand the dynamics of complex biochemical systems. To promote the modeling, we had developed the CADLIVE dynamic simulator that automatically converted a biochemical map into its associated mathematical model, simulated its dynamic behaviors and analyzed its robustness. To enhance the feasibility by CADLIVE and extend its functions, we propose the CADLIVE toolbox available for MATLAB, which implements not only the existing functions of the CADLIVE dynamic simulator, but also the latest tools including global parameter search methods with robustness analysis. The seamless, bottom-up processes consisting of biochemical network construction, automatic construction of its dynamic model, simulation, optimization, and S-system analysis greatly facilitate dynamic modeling, contributing to the research of systems biology and synthetic biology. This application can be freely downloaded from http://www.cadlive.jp/CADLIVE_MATLAB/ together with an instruction.
Analysis and synthesis for interval type-2 fuzzy-model-based systems
Li, Hongyi; Lam, Hak-Keung; Gao, Yabin
2016-01-01
This book develops a set of reference methods capable of modeling uncertainties existing in membership functions, and analyzing and synthesizing the interval type-2 fuzzy systems with desired performances. It also provides numerous simulation results for various examples, which fill certain gaps in this area of research and may serve as benchmark solutions for the readers. Interval type-2 T-S fuzzy models provide a convenient and flexible method for analysis and synthesis of complex nonlinear systems with uncertainties.
An Integrated Approach of Model checking and Temporal Fault Tree for System Safety Analysis
Energy Technology Data Exchange (ETDEWEB)
Koh, Kwang Yong; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)
2009-10-15
Digitalization of instruments and control systems in nuclear power plants offers the potential to improve plant safety and reliability through features such as increased hardware reliability and stability, and improved failure detection capability. It however makes the systems and their safety analysis more complex. Originally, safety analysis was applied to hardware system components and formal methods mainly to software. For software-controlled or digitalized systems, it is necessary to integrate both. Fault tree analysis (FTA) which has been one of the most widely used safety analysis technique in nuclear industry suffers from several drawbacks as described in. In this work, to resolve the problems, FTA and model checking are integrated to provide formal, automated and qualitative assistance to informal and/or quantitative safety analysis. Our approach proposes to build a formal model of the system together with fault trees. We introduce several temporal gates based on timed computational tree logic (TCTL) to capture absolute time behaviors of the system and to give concrete semantics to fault tree gates to reduce errors during the analysis, and use model checking technique to automate the reasoning process of FTA.
An Intelligent System for Modelling, Design and Analysis of Chemical Processes
DEFF Research Database (Denmark)
Gani, Rafiqul
ICAS, Integrated Computer Aided System, is a software that consists of a number of intelligent tools, which are very suitable, among others, for computer aided modelling, sustainable design of chemical and biochemical processes, and design-analysis of product-process monitoring systems. Each...... the computer aided modelling tool will illustrate how to generate a desired process model, how to analyze the model equations, how to extract data and identify the model and make it ready for various types of application. In sustainable process design, the example will highlight the issue of integration...... of these tools are characterized by a framework that follows an established work-flow and data-flow, developed to guide the user through the many steps of the problem solution process. At each, the specific tool knows which data, model and/or algorithm to use. The tool also provides analysis of the calculated...
Directory of Open Access Journals (Sweden)
Lubna Moin
2009-04-01
Full Text Available This research paper basically explores and compares the different modeling and analysis techniques and than it also explores the model order reduction approach and significance. The traditional modeling and simulation techniques for dynamic systems are generally adequate for single-domain systems only, but the Bond Graph technique provides new strategies for reliable solutions of multi-domain system. They are also used for analyzing linear and non linear dynamic production system, artificial intelligence, image processing, robotics and industrial automation. This paper describes a unique technique of generating the Genetic design from the tree structured transfer function obtained from Bond Graph. This research work combines bond graphs for model representation with Genetic programming for exploring different ideas on design space tree structured transfer function result from replacing typical bond graph element with their impedance equivalent specifying impedance lows for Bond Graph multiport. This tree structured form thus obtained from Bond Graph is applied for generating the Genetic Tree. Application studies will identify key issues and importance for advancing this approach towards becoming on effective and efficient design tool for synthesizing design for Electrical system. In the first phase, the system is modeled using Bond Graph technique. Its system response and transfer function with conventional and Bond Graph method is analyzed and then a approach towards model order reduction is observed. The suggested algorithm and other known modern model order reduction techniques are applied to a 11th order high pass filter [1], with different approach. The model order reduction technique developed in this paper has least reduction errors and secondly the final model retains structural information. The system response and the stability analysis of the system transfer function taken by conventional and by Bond Graph method is compared and
Directory of Open Access Journals (Sweden)
Shahid Ali
2009-04-01
Full Text Available This research paper basically explores and compares the different modeling and analysis techniques and than it also explores the model order reduction approach and significance. The traditional modeling and simulation techniques for dynamic systems are generally adequate for single-domain systems only, but the Bond Graph technique provides new strategies for reliable solutions of multi-domain system. They are also used for analyzing linear and non linear dynamic production system, artificial intelligence, image processing, robotics and industrial automation. This paper describes a unique technique of generating the Genetic design from the tree structured transfer function obtained from Bond Graph. This research work combines bond graphs for model representation with Genetic programming for exploring different ideas on design space tree structured transfer function result from replacing typical bond graph element with their impedance equivalent specifying impedance lows for Bond Graph multiport. This tree structured form thus obtained from Bond Graph is applied for generating the Genetic Tree. Application studies will identify key issues and importance for advancing this approach towards becoming on effective and efficient design tool for synthesizing design for Electrical system. In the first phase, the system is modeled using Bond Graph technique. Its system response and transfer function with conventional and Bond Graph method is analyzed and then a approach towards model order reduction is observed. The suggested algorithm and other known modern model order reduction techniques are applied to a 11th order high pass filter [1], with different approach. The model order reduction technique developed in this paper has least reduction errors and secondly the final model retains structural information. The system response and the stability analysis of the system transfer function taken by conventional and by Bond Graph method is compared and
Modeling and performance analysis of SAW reader systems for delay-line sensors.
Scheiblhofer, Stefan; Schuster, Stefan; Stelzer, Andreas
2009-10-01
In this contribution, we present a comprehensive modeling approach for delay line-based surface acoustic wave (SAW) sensor reader systems, which provides valuable insight into the interaction of the individual system parameters. A parametric analysis of signal strength, noise, and quantization effects and consideration of important signal processing parameters, such as data windows and averaging, allows prediction of the achievable statistical measurement accuracy by closed-form solutions. The performance and capabilities of the derived model are verified on system design examples as well as multiple practical measurement scenarios, using a prototype 2.45-GHz frequency-stepped continuous-wave SAW reader system.
Test and Sensitivity Analysis of Hydrological Modeling in the Coupled WRF-Urban Modeling System
Wang, Z.; yang, J.
2013-12-01
Rapid urbanization has emerged as the source of many adverse effects that challenge the environmental sustainability of cities under changing climatic patterns. One essential key to address these challenges is to physically resolve the dynamics of urban-land-atmospheric interactions. To investigate the impact of urbanization on regional climate, physically-based single layer urban canopy model (SLUCM) has been developed and implemented into the Weather Research and Forecasting (WRF) platform. However, due to the lack of realistic representation of urban hydrological processes, simulation of urban climatology by current coupled WRF-SLUCM is inevitably inadequate. Aiming at improving the accuracy of simulations, recently we implemented urban hydrological processes into the model, including (1) anthropogenic latent heat, (2) urban irrigation, (3) evaporation over impervious surface, and (4) urban oasis effect. In addition, we couple the green roof system into the model to verify its capacity in alleviating urban heat island effect at regional scale. Driven by different meteorological forcings, offline tests show that the enhanced model is more accurate in predicting turbulent fluxes arising from built terrains. Though the coupled WRF-SLUCM has been extensively tested against various field measurement datasets, accurate input parameter space needs to be specified for good model performance. As realistic measurements of all input parameters to the modeling framework are rarely possible, understanding the model sensitivity to individual parameters is essential to determine the relative importance of parameter uncertainty to model performance. Thus we further use an advanced Monte Carlo approach to quantify relative sensitivity of input parameters of the hydrological model. In particular, performance of two widely used soil hydraulic models, namely the van Genuchten model (based on generic soil physics) and an empirical model (viz. the CHC model currently adopted in WRF
Directory of Open Access Journals (Sweden)
M. A. Hussain
2014-01-01
Full Text Available This paper discusses the discrete-time stability analysis of a neural network inverse model control strategy for a relative order two nonlinear system. The analysis is done by representing the closed loop system in state space format and then analyzing the time derivative of the state trajectory using Lyapunov’s direct method. The analysis shows that the tracking output error of the states is confined to a ball in the neighborhood of the equilibrium point where the size of the ball is partly dependent on the accuracy of the neural network model acting as the controller. Simulation studies on the two-tank-in-series system were done to complement the stability analysis and to demonstrate some salient results of the study.
On power system blackout modeling and analysis based on self-organized criticality
Institute of Scientific and Technical Information of China (English)
2008-01-01
This paper makes a comprehensive survey on power system blackout modeling and analysis based on SOC (self-organized criticality). Firstly,a generalized SOC theory from the viewpoint of cybernetics is introduced. Then the evolution model of power system and its relative mathematical description,which serves as a concrete example of the proposed generalized SOC,are given. Secondly,five blackout models capturing various critical properties of power systems in different time-scales are listed. Finally,this paper analyzes SOC in power systems,such as,the revelation of criticalities of proposed models in both micro-scale and macro-scale which can be used to assess the security of power system,and cas-cading failures process.
On power system blackout modeling and analysis based on self-organized criticality
Institute of Scientific and Technical Information of China (English)
MEI ShengWei; XUE AnCheng; ZHANG XueMin
2008-01-01
This paper makes a comprehensive survey on power system blackout modeling and analysis based on SOC (self-organized criticality). Firstly, a generalized SOC theory from the viewpoint of cybernetics is introduced. Then the evolution model of power system and its relative mathematical description, which serves as a concrete example of the proposed generalized SOC, are given. Secondly, five blackout models capturing various critical properties of power systems in different time-scales are listed. Finally, this paper analyzes SOC in power systems, such as, the revelation of criticalities of proposed models in both micro-scale and macro-scale which can be used to assess the security of power system, and cascading failures process.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The problem of state space explosion is still an outstanding challenge in Markovian performance analysis for multiserver multiqueue (MSMQ) systems. The system behavior of a MSMQ system is described using stochastic high-level Petri net (SHLPN) models, and an approximate performance analysis technique is proposed based on decomposition and refinement methods as well as iteration technique. A real MSMQ system, Web-server cluster, is investigated. The performance of an integrated scheme of request dispatching and scheduling is analyzed with both Poisson and self-similar request arrivals. The study shows that the approximate analysis technique significantly reduces the complexity of the model solution and is also efficient for accuracy of numerical results.
Examination of Modeling Languages to Allow Quantitative Analysis for Model-Based Systems Engineering
2014-06-01
model of the system (Friendenthal, Moore and Steiner 2008, 17). The premise is that maintaining a logical and consistent model can be accomplished...Standard for Exchange of Product data (STEP) subgroup of ISO, and defines a standard data format for certain types of SE information ( Johnson 2006...search.credoreference.com/content/entry/encyccs/formal_languages/0. Friedenthal, Sanford, Alan Moore, and Rick Steiner . 2008. A Practical Guide to SysML
a Workflow for the Application of Sensitivity Analysis to Earth System Models
Pianosi, F.; Wagener, T.; Rougier, J.; Freer, J. E.; Hall, J.
2013-12-01
Predictions of any earth system model are affected by unavoidable and potentially large uncertainty. When models are used to support risk management of natural hazard, such uncertainties can undermine the transparency and defensibility of the risk assessment. When models are applied to understand dominant controls or other aspects of the system under study, uncertainties will reduce our ability to chose between competing hypotheses. Sensitivity Analysis (SA) provides quantitative information about the contribution of the different input factors (e.g. parameters, boundary conditions or forcing data) to such uncertainty. SA application thus provides insights into the model behavior and potential for model simplification, indicates where further data collection and research is needed or would be beneficial, and enhances the credibility of our modelling results. The value of such analysis has motivated an increasing research effort in the development, application and comparison of SA techniques. Still, comprehensive understanding to guide choices between available SA methods and practical guidelines for their application in the context of earth system models is still insufficient. In this contribution, we aim at filling this gap by (i) providing a map of the existing SA techniques and their appropriateness in different contexts of earth system modeling; (ii) developing a workflow for the choice and application of SA techniques to environmental models; (iii) presenting a suite of visualization tools that can support the assessment and communication of SA results; (iv) defining challenges and opportunities for future research.
Modeling and Analysis of a Low-Voltage DC Distribution System
Directory of Open Access Journals (Sweden)
Joon Han
2015-09-01
Full Text Available It is well known that the Low-Voltage DC (LVDC distribution system is a promising topology as a future smart distribution system due to its high efficiency and reliability. However, there are still some challenges in the construction and implementation of an LVDC system. For practical application of the LVDC system, therefore, it is necessary to perform any simulation in advance by considering various conditions that can occur in an LVDC system. In order to provide a foundation for analyzing a DC system, this paper presents an LVDC distribution system model including essential components such as power electronic devices, Distributed Energy Resource (DER, and Energy Storage System (ESS, which can be considered for implementation in an LVDC system using Electro-Magnetic Transient Program (EMTP software. Moreover, an analysis of the characteristic in both the steady state and the transient state is conducted in an LVDC distribution system.
MODELING AND PERFORMANCE ANALYSIS FOR THE SERIAL AND ARALLEL PRODUCTION SYSTEM BASED ON GSPN
Institute of Scientific and Technical Information of China (English)
Gao Jianhua; Hu Xudong; Yang Ruqing
2004-01-01
Differed from the existed applications of generalized stochastic Petri net (GSPN) theory in machine-tool manufacturing system, reliability computation of FMS, testability parameters determination and fault analysis, a new idea of applying GSPN to model and performance analysis for the serial and parallel production system is proposed. And one typical discrete event dynamic system (DEDS), turner-unit of palletizing system, is taken as a real case to research. Based upon the established GSPN models, the working performances of serial and parallel layout are compared. Furthermore, their differences of working mechanisms including feeding mechanism, coordinating mechanism and monitoring mechanism are discussed. Thus the theoretical basis which is helpful to appraise layout plan and its reasonableness is provided. Meanwhile, the research results show that parallel layout is more advantageous to greatly improve the operational speed of production system than serial one.
Directory of Open Access Journals (Sweden)
Natalia V. Kontsevaya
2016-01-01
Full Text Available In this work attempt of system approach to the analysis of labor market of youth is made, the place and a role of youth labor exchange are dened, opportunities and methods of state regulation are opened, contradictions in the analysis of the main market indicators are designated.Within system approach to the analysis of dynamics of market processes modeling of the main indicators of labor market in regional scale is shown.This approach can be useful when developing effective and economically reasonable mechanisms of employment of youth, both at the level of regional services of employment, and in the state scale
Computer-Aided Modeling and Analysis of Power Processing Systems (CAMAPPS), phase 1
Kim, S.; Lee, J.; Cho, B. H.; Lee, F. C.
1986-01-01
The large-signal behaviors of a regulator depend largely on the type of power circuit topology and control. Thus, for maximum flexibility, it is best to develop models for each functional block a independent modules. A regulator can then be configured by collecting appropriate pre-defined modules for each functional block. In order to complete the component model generation for a comprehensive spacecraft power system, the following modules were developed: solar array switching unit and control; shunt regulators; and battery discharger. The capability of each module is demonstrated using a simplified Direct Energy Transfer (DET) system. Large-signal behaviors of solar array power systems were analyzed. Stability of the solar array system operating points with a nonlinear load is analyzed. The state-plane analysis illustrates trajectories of the system operating point under various conditions. Stability and transient responses of the system operating near the solar array's maximum power point are also analyzed. The solar array system mode of operation is described using the DET spacecraft power system. The DET system is simulated for various operating conditions. Transfer of the software program CAMAPPS (Computer Aided Modeling and Analysis of Power Processing Systems) to NASA/GSFC (Goddard Space Flight Center) was accomplished.
Energy Technology Data Exchange (ETDEWEB)
Chen, D.J.
1988-01-01
The literature is abundant with combinatorial reliability analysis of communication networks and fault-tolerant computer systems. However, it is very difficult to formulate reliability indexes using combinatorial methods. These limitations have led to the development of time-dependent reliability analysis using stochastic processes. In this research, time-dependent reliability-analysis techniques using Dataflow Graphs (DGF) are developed. The chief advantages of DFG models over other models are their compactness, structural correspondence with the systems, and general amenability to direct interpretation. This makes the verification of the correspondence of the data-flow graph representation to the actual system possible. Several DGF models are developed and used to analyze the reliability of communication networks and computer systems. Specifically, Stochastic Dataflow graphs (SDFG), both the discrete-time and the continuous time models are developed and used to compute time-dependent reliability of communication networks and computer systems. The repair and coverage phenomenon of communication networks is also analyzed using SDFG models.
Dynamic modelling and analysis of multi-machine power systems including wind farms
Tabesh, Ahmadreza
2005-11-01
This thesis introduces a small-signal dynamic model, based on a frequency response approach, for the analysis of a multi-machine power system with special focus on an induction machine based wind farm. The proposed approach is an alternative method to the conventional eigenvalue analysis method which is widely employed for small-signal dynamic analyses of power systems. The proposed modelling approach is successfully applied and evaluated for a power system that (i) includes multiple synchronous generators, and (ii) a wind farm based on either fixed-speed, variable-speed, or doubly-fed induction machine based wind energy conversion units. The salient features of the proposed method, as compared with the conventional eigenvalue analysis method, are: (i) computational efficiency since the proposed method utilizes the open-loop transfer-function matrix of the system, (ii) performance indices that are obtainable based on frequency response data and quantitatively describe the dynamic behavior of the system, and (iii) capability to formulate various wind energy conversion unit, within a wind farm, in a modular form. The developed small-signal dynamic model is applied to a set of multi-machine study systems and the results are validated based on comparison (i) with digital time-domain simulation results obtained from PSCAD/EMTDC software tool, and (ii) where applicable with eigenvalue analysis results.
Directory of Open Access Journals (Sweden)
Rashmi S
2014-03-01
Full Text Available This paper proposes the Dynamic modeling and performance analysis of Permanent magnet synchronous generator (PMSG based Wind Generation System (WGS. This system consists of Wind Turbine, PMSG, Diode Rectifier, Buck- Boost converter, Voltage source Inverter (VSI. PMSG and Buck Boost converter are employed in WGS to get efficient output according to the load requirement without damaging the system. The output of the VSI is injected to the grid and used for Home Application. The proposed model dynamic simulation results are tested in MATLAB Simulink
A blackboard model of an expert system for failure mode and effects analysis
Russomanno, David J.; Bonnell, Ronald D.; Bowles, John B.
The design of an expert system to assist in performing a failure mode and effects analysis (FMEA) is approached from a knowledge-use-level perspective to provide a thorough understanding of the problem and insight into the knowledge and expertise needed to automate the FMEA process. A blackboard model is a conceptual model that provides the organizational principles required for the design of an expert system without actually specifying its realization. In the blackboard model of an intelligent FMEA, the system is functionally decomposed into a set of knowledge sources, each containing the knowledge associated with a subfunction of the FMEA process. The conceptual model derived can be used to evaluate attempts to automate the FMEA process, and it can serve as the foundation for further research into automating the FMEA process. An example is presented illustrating the interaction among the knowledge sources in the blackboard model to construct a FMEA for a domestic hot water heater.
Improved Analysis of Earth System Models and Observations using Simple Climate Models
Nadiga, Balasubramanya; Urban, Nathan
2017-04-01
First-principles-based Earth System Models (ESMs) are central to both improving our understanding of the climate system and developing climate projections. Nevertheless, given the diversity of climate simulated by the various ESMs and the intense computational burden associated with running such models, simple climate models (SCMs) are key to being able to compare ESMs and the climates they simulate in a dynamically meaningful fashion. We present some preliminary work along these lines. In an application of an SCM to compare different ESMs and observations, we demonstrate a deficiency in the commonly-used upwelling-diffusion (UD) energy balance model (EBM). When we consider the vertical distribution of ocean heat uptake, the lack of representation of processes such as deep water formation and subduction in the UD-EBM precludes a reasonable representation of the vertical distribution of heat uptake in that model. We then demonstrate how the problem can be remedied by introducing a parameterization of such processes in the UD-EBM. With further development, it is anticipated that this approach of ESM inter-comparison using simple physics-based models will lead to further insights into aspects of the climate response such as its stability and sensitivity, uncertainty and predictability, and underlying flow structure and topology.
Energy Technology Data Exchange (ETDEWEB)
Honrubia-Escribano, A.; Gomez Lazaro, E.; Jimenez-Buendia, F.; Muljadi, Eduard
2016-11-01
The International Electrotechnical Commission Standard 61400-27-1 was published in February 2015. This standard deals with the development of generic terms and parameters to specify the electrical characteristics of wind turbines. Generic models of very complex technological systems, such as wind turbines, are thus defined based on the four common configurations available in the market. Due to its recent publication, the comparison of the response of generic models with specific vendor models plays a key role in ensuring the widespread use of this standard. This paper compares the response of a specific Gamesa dynamic wind turbine model to the corresponding generic IEC Type III wind turbine model response when the wind turbine is subjected to a three-phase voltage dip. This Type III model represents the doubly-fed induction generator wind turbine, which is not only one of the most commonly sold and installed technologies in the current market but also a complex variable-speed operation implementation. In fact, active and reactive power transients are observed due to the voltage reduction. Special attention is given to the reactive power injection provided by the wind turbine models because it is a requirement of current grid codes. Further, the boundaries of the generic models associated with transient events that cannot be represented exactly are included in the paper.
Fuzzy cognitive maps outmatch loop analysis in dynamic modeling of ecological systems
Directory of Open Access Journals (Sweden)
Alessandro Ferrarini
2011-04-01
Full Text Available Modeling natural systems is challenging due to their complexity in terms of variables, interactions, and dynamics. Much of this complexity is rooted in the existence of multiple ways through which acting variables affect each other. Besides the simple direct effects, numerous indirect effects emerge in ecological systems. Through an illustrative example, I exemplify here several advantages of fuzzy cognitive maps (FCM over loop analysis (LA in dynamic modeling of ecological systems. In addition to being able to incorporate information about the magnitude of variables interactions, FCM can make predictions about multiple simultaneous perturbations. Furthermore, FCM allow for the simulation of different magnitude of initial perturbations to the system. Last, FCM estimate the amount of variable increase/decrease, not just the likely direction of change. Hence, even if LA is still much more used than FCM in the scientific literature, FCM can be considered fitter than LA in modeling ecological systems.
Energy Technology Data Exchange (ETDEWEB)
Lu, Yunfan, E-mail: yunfanlu@yeah.net; Wang, Jun; Niu, Hongli
2015-06-12
An agent-based financial stock price model is developed and investigated by a stochastic interacting epidemic system, which is one of the statistical physics systems and has been used to model the spread of an epidemic or a forest fire. Numerical and statistical analysis are performed on the simulated returns of the proposed financial model. Complexity properties of the financial time series are explored by calculating the correlation dimension and using the modified multiscale entropy method. In order to verify the rationality of the financial model, the real stock market indexes, Shanghai Composite Index and Shenzhen Component Index, are studied in comparison with the simulation data of the proposed model for the different infectiousness parameters. The empirical research reveals that this financial model can reproduce some important features of the real stock markets. - Highlights: • A new agent-based financial price model is developed by stochastic interacting epidemic system. • The structure of the proposed model allows to simulate the financial dynamics. • Correlation dimension and MMSE are applied to complexity analysis of financial time series. • Empirical results show the rationality of the proposed financial model.
System of Modelling and Calculation Analysis of Neutron- Physical Experiments at Fast Reactors
Energy Technology Data Exchange (ETDEWEB)
Moiseyev, A.V. [SSC RF - IPPE, 1 Bondarenko Square, Obninsk, Kaluga Region 249033 (Russian Federation)
2008-07-01
There is an actual task on storage, processing and analysis of the unique experimental data received on power fast reactors for their subsequent use in projects of fast reactors of new (4.) generation. For modeling and carrying out analysis of experiments the integrated computing system MODEXSYS has been developed. In this system the mechanism for consecutive calculation of a fast reactor states with the detailed description of its components is created. The system includes the database describing fast reactor states, results of neutron-physical characteristics measurements at fast reactor, calculation and benchmark models of experiments and calculation results. In system convenient search means and the special graphics shell are provided. It has Interfaces for processing of calculation results and their analysis. MODEXSYS system has been applied for analysis of three types of experiments at fast reactor: k{sub eff}, control rod worth and energy release distribution. The most important results of this analysis are described. Application of MODEXSYS system will raise accuracy and reliability of forecasting of fast reactors neutron-physical characteristics; for BN-600 reactor recommended level of accuracy is resulted. (authors)
Chapman, Jeffryes W.; Lavelle, Thomas M.; May, Ryan D.; Litt, Jonathan S.; Guo, Ten-Huei (OA)
2014-01-01
A simulation toolbox has been developed for the creation of both steady-state and dynamic thermodynamic software models. This presentation describes the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS), which combines generic thermodynamic and controls modeling libraries with a numerical iterative solver to create a framework for the development of thermodynamic system simulations, such as gas turbine engines. The objective of this presentation is to present an overview of T-MATS, the theory used in the creation of the module sets, and a possible propulsion simulation architecture.
Thermal-hydraulic modeling and analysis of hydraulic system by pseudo-bond graph
Institute of Scientific and Technical Information of China (English)
胡均平; 李科军
2015-01-01
To increase the efficiency and reliability of the thermodynamics analysis of the hydraulic system, the method based on pseudo-bond graph is introduced. According to the working mechanism of hydraulic components, they can be separated into two categories: capacitive components and resistive components. Then, the thermal-hydraulic pseudo-bond graphs of capacitive C element and resistance R element were developed, based on the conservation of mass and energy. Subsequently, the connection rule for the pseudo-bond graph elements and the method to construct the complete thermal-hydraulic system model were proposed. On the basis of heat transfer analysis of a typical hydraulic circuit containing a piston pump, the lumped parameter mathematical model of the system was given. The good agreement between the simulation results and experimental data demonstrates the validity of the modeling method.
Model-based Computer Aided Framework for Design of Process Monitoring and Analysis Systems
DEFF Research Database (Denmark)
Singh, Ravendra; Gernaey, Krist; Gani, Rafiqul
2009-01-01
-aided framework including the methods and tools through which the design of monitoring and analysis systems for product quality control can be generated, analyzed and/or validated, has been developed. Two important supporting tools developed as part of the framework are a knowledge base and a model library...... subject to the maintenance constraints of the desired product quality. The application of the model-based framework is highlighted through a case study involving the operation of a fermentation process.......In the manufacturing industry, for example, the pharmaceutical industry, a thorough understanding of the process is necessary in addition to a properly designed monitoring and analysis system (PAT system) to consistently obtain the desired end-product properties. A model-based computer...
LCA of waste management systems: Development of tools for modeling and uncertainty analysis
DEFF Research Database (Denmark)
Clavreul, Julie
to be modelled rather than monitored as in classical LCA (e.g. landfilling or the application of processed waste on agricultural land). Therefore LCA-tools are needed which specifically address these issues and enable practitioners to model properly their systems. In this thesis several pieces of work...... are presented. First a review was carried out on all LCA studies of waste management systems published before mid-2012. This provided a global overview of the technologies and waste fractions which have attracted focus within LCA while enabling an analysis of methodological tendencies, the use of tools...... and databases and the application of uncertainty analysis methods. The major outcome of this thesis was the development of a new LCA model, called EASETECH, building on the experience with previous LCA-tools, in particular the EASEWASTE model. Before the actual implementation phase, a design phase involved...
DEFF Research Database (Denmark)
Patou, François; Madsen, Jan; Dimaki, Maria
2016-01-01
, methodologies enabling scalability analysis of multidomain, complex systems, are still missing. In acknowledgment of the importance for complex systems to present the ability to change or evolve, we present in this work a systemlevel model-based methodology allowing the multidisciplinary parametric evaluation......Scalability is a design principle often valued for the engineering of complex systems. Scalability is the ability of a system to change the current value of one of its specification parameters. Although targeted frameworks are available for the evaluation of scalability for specific digital systems......-engineering efforts for scaling a system specification efficaciously. We demonstrate the value of our methodology by investigating a smartphone-based biosensing instrumentation platform. Specifically, we carry out scalability analysis for the system’s bandwidth specification: the maximum analog voltage waveform...
Berzina, Alise; Dace, Elina; Bazbauers, Gatis
2010-01-01
This paper discusses the findings of a research project which explored the packaging waste management system in Latvia. The paper focuses on identifying how the policy mechanisms can promote ecodesign implementation and material efficiency improvement and therefore reduce the rate of packaging waste accumulation in landfill. The method used for analyzing the packaging waste management policies is system dynamics modeling. The main conclusion is that the existing legislative instruments can be used to create an effective policy for ecodesign implementation but substantially higher tax rates on packaging materials and waste disposal than the existing have to be applied.
Modeling and Analysis of Scheduling for Distributed Real-time Embedded Systems
Institute of Scientific and Technical Information of China (English)
Hai-Tao Zhang; Gui-Fang Wu
2010-01-01
Aimed at the deficiencies of resources based time Petri nets(RBTPN)in doing scheduling analysis for distributed real-time embedded systems,the assemblage condition of complex scheduling sequences is presented to easily compute scheduling length and simplify scheduling analysis.Based on this,a new hierarchical RBTPN model is proposed.The model introduces the definition of transition border set,and represents it as an abstract transition.The abstract transition possesses all resources of the set,and has the highest priority of each resource;the execution time of abstract transition is the longest time of all possible scheduling sequences.According to the characteristics and assemblage condition of RBTPN,the refinement conditions of transition border set are given,and the conditions ensure the correction of scheduling analysis.As a result,it is easy for us to understand the scheduling model and perform scheduling analysis.
Energy Technology Data Exchange (ETDEWEB)
Lahtinen, J.; Bjoerkman, K.; Valkonen, J.; Frits, J.; Niemelae, I.
2010-12-15
Digital instrumentation and control (I and C) systems containing programmable logic controllers are challenging to verify. They enable complicated control functions and the state spaces (number of distinct values of inputs, outputs and internal memory) of the designs easily become too large for comprehensive manual inspection. Model checking is a formal method that can be used for verifying that systems have been correctly designed. A number of efficient model checking systems are available which provide analysis tools that are able to determine automatically whether a given state machine model satisfies the desired safety properties. The practical case analysed in this research project is called an 'emergency diesel generator control system' and its purpose is to provide reserve power to critical devices and computers that must be available without interruption. This report describes 1) the development of a compositional approach for checking the models in large system designs, 2) the development of a modular model checking approach for modelling function block diagrams with the Uppaal model checker and 3) the experience of utilising the new modelling approaches in practice. (orig.)
Leonard, J. I.
1974-01-01
Included in the report are: (1) review of the erythropoietic mechanisms; (2) an evaluation of existing models for the control of erythropoiesis; (3) a computer simulation of the model's response to hypoxia; (4) an hypothesis to explain observed decreases in red blood cell mass during weightlessness; (5) suggestions for further research; and (6) an assessment of the role that systems analysis can play in the Skylab hematological program.
Chapman, Jeffryes W.; Lavelle, Thomas M.; May, Ryan D.; Litt, Jonathan S.; Guo, Ten-Huei
2014-01-01
A simulation toolbox has been developed for the creation of both steady-state and dynamic thermodynamic software models. This paper describes the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS), which combines generic thermodynamic and controls modeling libraries with a numerical iterative solver to create a framework for the development of thermodynamic system simulations, such as gas turbine engines. The objective of this paper is to present an overview of T-MATS, the theory used in the creation of the module sets, and a possible propulsion simulation architecture. A model comparison was conducted by matching steady-state performance results from a T-MATS developed gas turbine simulation to a well-documented steady-state simulation. Transient modeling capabilities are then demonstrated when the steady-state T-MATS model is updated to run dynamically.
Chapman, Jeffryes W.; Lavelle, Thomas M.; May, Ryan D.; Litt, Jonathan S.; Guo, Ten-Huei
2014-01-01
A simulation toolbox has been developed for the creation of both steady-state and dynamic thermodynamic software models. This paper describes the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS), which combines generic thermodynamic and controls modeling libraries with a numerical iterative solver to create a framework for the development of thermodynamic system simulations, such as gas turbine engines. The objective of this paper is to present an overview of T-MATS, the theory used in the creation of the module sets, and a possible propulsion simulation architecture. A model comparison was conducted by matching steady-state performance results from a T-MATS developed gas turbine simulation to a well-documented steady-state simulation. Transient modeling capabilities are then demonstrated when the steady-state T-MATS model is updated to run dynamically.
A data integration approach for cell cycle analysis oriented to model simulation in systems biology
Directory of Open Access Journals (Sweden)
Mosca Ettore
2007-08-01
Full Text Available Abstract Background The cell cycle is one of the biological processes most frequently investigated in systems biology studies and it involves the knowledge of a large number of genes and networks of protein interactions. A deep knowledge of the molecular aspect of this biological process can contribute to making cancer research more accurate and innovative. In this context the mathematical modelling of the cell cycle has a relevant role to quantify the behaviour of each component of the systems. The mathematical modelling of a biological process such as the cell cycle allows a systemic description that helps to highlight some features such as emergent properties which could be hidden when the analysis is performed only from a reductionism point of view. Moreover, in modelling complex systems, a complete annotation of all the components is equally important to understand the interaction mechanism inside the network: for this reason data integration of the model components has high relevance in systems biology studies. Description In this work, we present a resource, the Cell Cycle Database, intended to support systems biology analysis on the Cell Cycle process, based on two organisms, yeast and mammalian. The database integrates information about genes and proteins involved in the cell cycle process, stores complete models of the interaction networks and allows the mathematical simulation over time of the quantitative behaviour of each component. To accomplish this task, we developed, a web interface for browsing information related to cell cycle genes, proteins and mathematical models. In this framework, we have implemented a pipeline which allows users to deal with the mathematical part of the models, in order to solve, using different variables, the ordinary differential equation systems that describe the biological process. Conclusion This integrated system is freely available in order to support systems biology research on the cell cycle and
KINETIC MODELLING AND PERFORMANCE ANALYSIS OF THE FOUR-POST-FRAME LIFTINGMECHANICAL SYSTEM
Institute of Scientific and Technical Information of China (English)
高建华; 杨汝清; 胡洪国
2001-01-01
The kinetic model of the four-post-frame lifting mechanical system was established. The stiffness and damping matrices of differential equations of motion were obtained by using Lagrange's equations. And the dynamic characteristics of system were analyzed by modal analysis method. Based upon this, the modifications of structural parameters which can improve dynamic performance were discussed. The low-level high-speed palletizer MDJ1200L was taken as a real case in the paper.
The analysis of the dynamical system arising from Gray — Scott model
Krishchenko, A. P.; Kanatnikov, A. N.
2016-06-01
The Gray — Scott system used as a model of three-component autocatalytic reaction X + 2Y → Y, Y → Z, demonstrates the complex behavior and was studied in a number of papers. In this work we refine the known results of the bifurcation analysis of the Gray — Scott system and show them by diagram in parameter space. In addition we construct localizing sets for compact invariant sets of the system, i.e. the sets in the phase space containing all compact invariant sets of the system.
Michaelis, A.; Nemani, R. R.; Wang, W.; Votava, P.; Hashimoto, H.
2010-12-01
Given the increasing complexity of climate modeling and analysis tools, it is often difficult and expensive to build or recreate an exact replica of the software compute environment used in past experiments. With the recent development of new technologies for hardware virtualization, an opportunity exists to create full modeling, analysis and compute environments that are “archiveable”, transferable and may be easily shared amongst a scientific community or presented to a bureaucratic body if the need arises. By encapsulating and entire modeling and analysis environment in a virtual machine image, others may quickly gain access to the fully built system used in past experiments, potentially easing the task and reducing the costs of reproducing and verify past results produced by other researchers. Moreover, these virtual machine images may be used as a pedagogical tool for others that are interested in performing an academic exercise but don't yet possess the broad expertise required. We built two virtual machine images, one with the Community Earth System Model (CESM) and one with Weather Research Forecast Model (WRF), then ran several small experiments to assess the feasibility, performance overheads costs, reusability, and transferability. We present a list of the pros and cons as well as lessoned learned from utilizing virtualization technology in the climate and earth systems modeling domain.
Space Weather Influence on Power Systems: Prediction, Risk Analysis, and Modeling
Yatsenko, Vitaliy
2016-04-01
This report concentrates on dynamic probabilistic risk analysis of optical elements for complex characterization of damages using physical model of solid state lasers and predictable level of ionizing radiation and space weather. The following main subjects will be covered by our report: (a) solid-state laser model; (b) mathematical models for dynamic probabilistic risk assessment; and (c) software for modeling and prediction of ionizing radiation. A probabilistic risk assessment method for solid-state lasers is presented with consideration of some deterministic and stochastic factors. Probabilistic risk assessment is a comprehensive, structured, and logical analysis method aimed at identifying and assessing risks in solid-state lasers for the purpose of cost-e®ectively improving their safety and performance. This method based on the Conditional Value-at-Risk measure (CVaR) and the expected loss exceeding Value-at-Risk (VaR). We propose to use a new dynamical-information approach for radiation damage risk assessment of laser elements by cosmic radiation. Our approach includes the following steps: laser modeling, modeling of ionizing radiation in°uences on laser elements, probabilistic risk assessment methods, and risk minimization. For computer simulation of damage processes at microscopic and macroscopic levels the following methods are used: () statistical; (b) dynamical; (c) optimization; (d) acceleration modeling, and (e) mathematical modeling of laser functioning. Mathematical models of space ionizing radiation in°uence on laser elements were developed for risk assessment in laser safety analysis. This is a so-called `black box' or `input-output' models, which seeks only to reproduce the behaviour of the system's output in response to changes in its inputs. The model inputs are radiation in°uences on laser systems and output parameters are dynamical characteristics of the solid laser. Algorithms and software for optimal structure and parameters of
Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.; Meisner, Gregory P.
2013-04-01
A numerical model has been developed to simulate coupled thermal and electrical energy transfer processes in a thermoelectric generator (TEG) designed for automotive waste heat recovery systems. This model is capable of computing the overall heat transferred, the electrical power output, and the associated pressure drop for given inlet conditions of the exhaust gas and the available TEG volume. Multiple-filled skutterudites and conventional bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from exhaust into usable electrical power. Heat transfer between the hot exhaust gas and the hot side of the TEMs is enhanced with the use of a plate-fin heat exchanger integrated within the TEG and using liquid coolant on the cold side. The TEG is discretized along the exhaust flow direction using a finite-volume method. Each control volume is modeled as a thermal resistance network which consists of integrated submodels including a heat exchanger and a thermoelectric device. The pressure drop along the TEG is calculated using standard pressure loss correlations and viscous drag models. The model is validated to preserve global energy balances and is applied to analyze a prototype TEG with data provided by General Motors. Detailed results are provided for local and global heat transfer and electric power generation. In the companion paper, the model is then applied to consider various TEG topologies using skutterudite and bismuth telluride TEMs.
Analysis of a model of fuel cell - gas turbine hybrid power system for enhanced energy efficiency
Calay, Rajnish K.; Mustafa, Mohamad Y.; Virk, Mohammad S.; Mustafa, Mahmoud F.
2012-11-01
A simple mathematical model to evaluate the performance of FC-GT hybrid system is presented in this paper. The model is used to analyse the influence of various parameters on the performance of a typical hybrid system, where excess heat rejected from the solid-oxide fuel cell stack is utilised to generate additional power through a gas turbine system and to provide heat energy for space heating. The model is based on thermodynamic analysis of various components of the plant and can be adapted for various configurations of the plant components. Because there are many parameters defining the efficiency and work output of the hybrid system, the technique is based on mathematical and graphical optimisation of various parameters; to obtain the maximum efficiency for a given plant configuration.
Evaluating Domestic Hot Water Distribution System Options with Validated Analysis Models
Energy Technology Data Exchange (ETDEWEB)
Weitzel, E. [Alliance for Residential Building Innovation, Davis, CA (United States); Hoeschele, E. [Alliance for Residential Building Innovation, Davis, CA (United States)
2014-09-01
A developing body of work is forming that collects data on domestic hot water consumption, water use behaviors, and energy efficiency of various distribution systems. Transient System Simulation Tool (TRNSYS) is a full distribution system developed that has been validated using field monitoring data and then exercised in a number of climates to understand climate impact on performance. In this study, the Building America team built upon previous analysis modeling work to evaluate differing distribution systems and the sensitivities of water heating energy and water use efficiency to variations of climate, load, distribution type, insulation and compact plumbing practices. Overall, 124 different TRNSYS models were simulated. The results of this work are useful in informing future development of water heating best practices guides as well as more accurate (and simulation time efficient) distribution models for annual whole house simulation programs.
A model for improving energy efficiency in industrial motor system using multicriteria analysis
Energy Technology Data Exchange (ETDEWEB)
Herrero Sola, Antonio Vanderley, E-mail: sola@utfpr.edu.br [Federal University of Technology, Parana, Brazil (UTFPR)-Campus Ponta Grossa, Av. Monteiro Lobato, Km 4, CEP: 84016-210 (Brazil); Mota, Caroline Maria de Miranda, E-mail: carolmm@ufpe.br [Federal University of Pernambuco, Cx. Postal 7462, CEP 50630-970, Recife (Brazil); Kovaleski, Joao Luiz [Federal University of Technology, Parana, Brazil (UTFPR)-Campus Ponta Grossa, Av. Monteiro Lobato, Km 4, CEP: 84016-210 (Brazil)
2011-06-15
In the last years, several policies have been proposed by governments and global institutions in order to improve the efficient use of energy in industries worldwide. However, projects in industrial motor systems require new approach, mainly in decision making area, considering the organizational barriers for energy efficiency. Despite the wide application, multicriteria methods remain unexplored in industrial motor systems until now. This paper proposes a multicriteria model using the PROMETHEE II method, with the aim of ranking alternatives for induction motors replacement. A comparative analysis of the model, applied to a Brazilian industry, has shown that multicriteria analysis presents better performance on energy saving as well as return on investments than single criterion. The paper strongly recommends the dissemination of multicriteria decision aiding as a policy to support the decision makers in industries and to improve energy efficiency in electric motor systems. - Highlights: > Lack of decision model in industrial motor system is the main motivation of the research. > A multicriteria model based on PROMETHEE method is proposed with the aim of supporting the decision makers in industries. > The model can contribute to transpose some barriers within the industries, improving the energy efficiency in industrial motor system.
A Model of System and Strategic Financial Analysis of the Crimean Health Resorts
Directory of Open Access Journals (Sweden)
Vadim Anatolyevich Malyshenko
2016-06-01
Full Text Available The subject matter of the research is the system of strategically focused financial analysis regarding an assessment of the financial condition of the enterprise. The hypothesis of the study is to assume the possibility of developing the financial and strategic model of the comprehensive assessment of the financial condition taking into account the integrated impact of environmental factors (general for the most Crimean health resorts. The methodology of the work is based on the most general principles of system analysis. The basic method of the research is the matrix method as the most common one for the system analysis. The graphical and statistical methods are also used. The result of the work is the comprehensive method of financial analysis developed as a model based on the matrix relation between the original visual profile of the internal environment and the dynamic type of external environment. The difference of the visual model of financial state from the existing graphic methods consists in fixing of the new strategic types of financial state on the basis of financial stability in visually grouped areas of financial coefficients in theme groups (configurationsprofiles with certain combinations of the forms and sizes. The new analytical instrument of «frigate model» can be applied in all analytical activities of the health resorts departments related to the analytical assessment of financial state. The advantage of «frigate model» in comparison with a classical method of the forming of the types of financial condition is that the proposed model allows to allocate more differentiated types and in addition, to identify the stages of enterprise life cycle based on the relative indicators of the analysis of financial state (objects-coefficients, and not just on the financial management. Through this, the consistency of interaction between the financial analysis and management is achieved.
Efficient Analysis of Systems Biology Markup Language Models of Cellular Populations Using Arrays.
Watanabe, Leandro; Myers, Chris J
2016-08-19
The Systems Biology Markup Language (SBML) has been widely used for modeling biological systems. Although SBML has been successful in representing a wide variety of biochemical models, the core standard lacks the structure for representing large complex regular systems in a standard way, such as whole-cell and cellular population models. These models require a large number of variables to represent certain aspects of these types of models, such as the chromosome in the whole-cell model and the many identical cell models in a cellular population. While SBML core is not designed to handle these types of models efficiently, the proposed SBML arrays package can represent such regular structures more easily. However, in order to take full advantage of the package, analysis needs to be aware of the arrays structure. When expanding the array constructs within a model, some of the advantages of using arrays are lost. This paper describes a more efficient way to simulate arrayed models. To illustrate the proposed method, this paper uses a population of repressilator and genetic toggle switch circuits as examples. Results show that there are memory benefits using this approach with a modest cost in runtime.
Double-blind comparison of survival analysis models using a bespoke web system.
Taktak, A F G; Setzkorn, C; Damato, B E
2006-01-01
The aim of this study was to carry out a comparison of different linear and non-linear models from different centres on a common dataset in a double-blind manner to eliminate bias. The dataset was shared over the Internet using a secure bespoke environment called geoconda. Models evaluated included: (1) Cox model, (2) Log Normal model, (3) Partial Logistic Spline, (4) Partial Logistic Artificial Neural Network and (5) Radial Basis Function Networks. Graphical analysis of the various models with the Kaplan-Meier values were carried out in 3 survival groups in the test set classified according to the TNM staging system. The discrimination value for each model was determined using the area under the ROC curve. Results showed that the Cox model tended towards optimism whereas the partial logistic Neural Networks showed slight pessimism.
Polichtchouk, Yuri; Ryukhko, Viatcheslav; Tokareva, Olga; Alexeeva, Mary
2002-02-01
Geoinformation modeling system structure for assessment of the environmental impact of atmospheric pollution on forest- swamp ecosystems of West Siberia is considered. Complex approach to the assessment of man-caused impact based on the combination of sanitary-hygienic and landscape-geochemical approaches is reported. Methodical problems of analysis of atmosphere pollution impact on vegetable biosystems using geoinformation systems and remote sensing data are developed. Landscape structure of oil production territories in southern part of West Siberia are determined on base of processing of space images from spaceborn Resource-O. Particularities of atmosphere pollution zones modeling caused by gas burning in torches in territories of oil fields are considered. For instance, a pollution zones were revealed modeling of contaminants dispersal in atmosphere by standard model. Polluted landscapes areas are calculated depending on oil production volume. It is shown calculated data is well approximated by polynomial models.
Incorporating Fuzzy Systems Modeling and Possibility Theory in Hydrogeological Uncertainty Analysis
Faybishenko, B.
2008-12-01
Hydrogeological predictions are subject to numerous uncertainties, including the development of conceptual, mathematical, and numerical models, as well as determination of their parameters. Stochastic simulations of hydrogeological systems and the associated uncertainty analysis are usually based on the assumption that the data characterizing spatial and temporal variations of hydrogeological processes are random, and the output uncertainty is quantified using a probability distribution. However, hydrogeological systems are often characterized by imprecise, vague, inconsistent, incomplete or subjective information. One of the modern approaches to modeling and uncertainty quantification of such systems is based on using a combination of statistical and fuzzy-logic uncertainty analyses. The aims of this presentation are to: (1) present evidence of fuzziness in developing conceptual hydrogeological models, and (2) give examples of the integration of the statistical and fuzzy-logic analyses in modeling and assessing both aleatoric uncertainties (e.g., caused by vagueness in assessing the subsurface system heterogeneities of fractured-porous media) and epistemic uncertainties (e.g., caused by the selection of different simulation models) involved in hydrogeological modeling. The author will discuss several case studies illustrating the application of fuzzy modeling for assessing the water balance and water travel time in unsaturated-saturated media. These examples will include the evaluation of associated uncertainties using the main concepts of possibility theory, a comparison between the uncertainty evaluation using probabilistic and possibility theories, and a transformation of the probabilities into possibilities distributions (and vice versa) for modeling hydrogeological processes.
A 5-DOF Model for Aeroengine Spindle Dual-rotor System Analysis
Institute of Scientific and Technical Information of China (English)
HU Qinghua; DENG Sier; TENG Hongfei
2011-01-01
This paper develops a five degrees of freedom (5-DOF) model for aeroengine spindle dual-rotor system dynamic analysis.In this system, the dual rotors are supported on two angular contact ball bearings and two deep groove ball bearings, one of the latter-mentioned bearings works as the inter-shaft bearing.Driven by respective motors, the dual rotors have different co-rotating speeds.The proposed model mathematically formulates the nonlinear displacements, elastic deflections and contact forces of beatings with consideration of 5-DOF and coupling of dual rotors.The nonlinear equations of motions of dual rotors with 5-DOF are solved using Runge-Kutta-Fehlberg algorithm.In order to investigate the effect of the introduced 5-DOF and nonlinear dynamic bearing model, we compare the proposed model with two models: the 3-DOF model of this system only considering three translational degrees of freedom (Gupta, 1993, rotational freedom is neglected); the 5-DOF model where the deep groove ball bearings are simplified as linear elastic spring (Guskov, 2007).The simulation results verify Gupta's prediction (1993) and show that the rotational freedom of rotors and nonlinear dynamic model of bearings have great effect on the system dynamic simulation.The quantitative results are given as well.
An Analysis of the Control Hierarchy Modeling of the CMS Detector Control System
Ling Hwong, Yi
2010-01-01
The supervisory level of the Detector Control System (DCS) of the CMS experiment is implemented using Finite State Machines (FSM), which model the behaviors and control the operations of all the sub-detectors and support services. The FSM tree of the whole CMS experiment consists of more than 30.000 nodes. An analysis of a system of such size is a complex task but is a crucial step towards the improvement of the overall performance of the FSM system. This paper presents the analysis of the CMS FSM system using the micro Common Representation Language 2 (mcrl2) methodology. Individual mCRL2 models are obtained for the FSM systems of the CMS sub-detectors using the ASF+SDF automated translation tool. Different mCRL2 operations are applied to the mCRL2 models. A mCRL2 simulation tool is used to closer examine the system. Visualization of a system based on the exploration of its state space is enabled with a mCRL2 tool. Requirements such as command and state propagation are expressed using modal mu-calculus and c...
Directory of Open Access Journals (Sweden)
Tuan Anh Nguyen
2014-01-01
Full Text Available It is important to assess availability of virtualized systems in IT business infrastructures. Previous work on availability modeling and analysis of the virtualized systems used a simplified configuration and assumption in which only one virtual machine (VM runs on a virtual machine monitor (VMM hosted on a physical server. In this paper, we show a comprehensive availability model using stochastic reward nets (SRN. The model takes into account (i the detailed failures and recovery behaviors of multiple VMs, (ii various other failure modes and corresponding recovery behaviors (e.g., hardware faults, failure and recovery due to Mandelbugs and aging-related bugs, and (iii dependency between different subcomponents (e.g., between physical host failure and VMM, etc. in a virtualized servers system. We also show numerical analysis on steady state availability, downtime in hours per year, transaction loss, and sensitivity analysis. This model provides a new finding on how to increase system availability by combining both software rejuvenations at VM and VMM in a wise manner.
Recent developments in imaging system assessment methodology, FROC analysis and the search model.
Chakraborty, Dev P
2011-08-21
A frequent problem in imaging is assessing whether a new imaging system is an improvement over an existing standard. Observer performance methods, in particular the receiver operating characteristic (ROC) paradigm, are widely used in this context. In ROC analysis lesion location information is not used and consequently scoring ambiguities can arise in tasks, such as nodule detection, involving finding localized lesions. This paper reviews progress in the free-response ROC (FROC) paradigm in which the observer marks and rates suspicious regions and the location information is used to determine whether lesions were correctly localized. Reviewed are FROC data analysis, a search-model for simulating FROC data, predictions of the model and a method for estimating the parameters. The search model parameters are physically meaningful quantities that can guide system optimization.
Validating the physical model of a chaotic system by topological analysis.
Used, Javier; Martín, Juan Carlos
2013-05-01
Topological analysis is employed for the first time to our knowledge as a method of validation for a physical model describing a chaotic system. Topological analysis theory provides both a way to characterize the topological structure of chaotic attractors by means of a set of integer numbers and a method to obtain this set departing from a time series generated by the chaotic system. The validation method proposed here consists of comparing the topological structure of chaotic attractors obtained from time series generated on the one hand by an experimental system and on the other hand by the numerical model under test. This procedure has been applied to an erbium-doped fiber laser subject to pump power sine-wave modulation.
Validating the physical model of a chaotic system by topological analysis
Used, Javier; Martín, Juan Carlos
2013-05-01
Topological analysis is employed for the first time to our knowledge as a method of validation for a physical model describing a chaotic system. Topological analysis theory provides both a way to characterize the topological structure of chaotic attractors by means of a set of integer numbers and a method to obtain this set departing from a time series generated by the chaotic system. The validation method proposed here consists of comparing the topological structure of chaotic attractors obtained from time series generated on the one hand by an experimental system and on the other hand by the numerical model under test. This procedure has been applied to an erbium-doped fiber laser subject to pump power sine-wave modulation.
Iacobucci, Joseph V.
The research objective for this manuscript is to develop a Rapid Architecture Alternative Modeling (RAAM) methodology to enable traceable Pre-Milestone A decision making during the conceptual phase of design of a system of systems. Rather than following current trends that place an emphasis on adding more analysis which tends to increase the complexity of the decision making problem, RAAM improves on current methods by reducing both runtime and model creation complexity. RAAM draws upon principles from computer science, system architecting, and domain specific languages to enable the automatic generation and evaluation of architecture alternatives. For example, both mission dependent and mission independent metrics are considered. Mission dependent metrics are determined by the performance of systems accomplishing a task, such as Probability of Success. In contrast, mission independent metrics, such as acquisition cost, are solely determined and influenced by the other systems in the portfolio. RAAM also leverages advances in parallel computing to significantly reduce runtime by defining executable models that are readily amendable to parallelization. This allows the use of cloud computing infrastructures such as Amazon's Elastic Compute Cloud and the PASTEC cluster operated by the Georgia Institute of Technology Research Institute (GTRI). Also, the amount of data that can be generated when fully exploring the design space can quickly exceed the typical capacity of computational resources at the analyst's disposal. To counter this, specific algorithms and techniques are employed. Streaming algorithms and recursive architecture alternative evaluation algorithms are used that reduce computer memory requirements. Lastly, a domain specific language is created to provide a reduction in the computational time of executing the system of systems models. A domain specific language is a small, usually declarative language that offers expressive power focused on a particular
Designing novel cellulase systems through agent-based modeling and global sensitivity analysis
Apte, Advait A; Senger, Ryan S; Fong, Stephen S
2014-01-01
Experimental techniques allow engineering of biological systems to modify functionality; however, there still remains a need to develop tools to prioritize targets for modification. In this study, agent-based modeling (ABM) was used to build stochastic models of complexed and non-complexed cellulose hydrolysis, including enzymatic mechanisms for endoglucanase, exoglucanase, and β-glucosidase activity. Modeling results were consistent with experimental observations of higher efficiency in complexed systems than non-complexed systems and established relationships between specific cellulolytic mechanisms and overall efficiency. Global sensitivity analysis (GSA) of model results identified key parameters for improving overall cellulose hydrolysis efficiency including: (1) the cellulase half-life, (2) the exoglucanase activity, and (3) the cellulase composition. Overall, the following parameters were found to significantly influence cellulose consumption in a consolidated bioprocess (CBP): (1) the glucose uptake rate of the culture, (2) the bacterial cell concentration, and (3) the nature of the cellulase enzyme system (complexed or non-complexed). Broadly, these results demonstrate the utility of combining modeling and sensitivity analysis to identify key parameters and/or targets for experimental improvement. PMID:24830736
P50/P90 Analysis for Solar Energy Systems Using the System Advisor Model: Preprint
Energy Technology Data Exchange (ETDEWEB)
Dobos, A. P.; Gilman, P.; Kasberg, M.
2012-06-01
To secure competitive financing for a solar energy generation project, the economic risk associated with interannual solar resource variability must be quantified. One way to quantify this risk is to calculate exceedance probabilities representing the amount of energy expected to be produced by a plant. Many years of solar radiation and metereological data are required to determine these values, often called P50 or P90 values for the level of certainty they represent. This paper describes the two methods implemented in the National Renewable Energy Laboratory's System Advisor Model (SAM) to calculate P50 and P90 exceedance probabilities for solar energy projects. The methodology and supporting data sets are applicable to photovoltaic, solar water heating, and concentrating solar power (CSP) systems.
Cantera Integration with the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS)
Lavelle, Thomas M.; Chapman, Jeffryes W.; May, Ryan D.; Litt, Jonathan S.; Guo, Ten-Huei
2014-01-01
NASA Glenn Research Center (GRC) has recently developed a software package for modeling generic thermodynamic systems called the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a library of building blocks that can be assembled to represent any thermodynamic system in the Simulink (The MathWorks, Inc.) environment. These elements, along with a Newton Raphson solver (also provided as part of the T-MATS package), enable users to create models of a wide variety of systems. The current version of T-MATS (v1.0.1) uses tabular data for providing information about a specific mixture of air, water (humidity), and hydrocarbon fuel in calculations of thermodynamic properties. The capabilities of T-MATS can be expanded by integrating it with the Cantera thermodynamic package. Cantera is an object-oriented analysis package that calculates thermodynamic solutions for any mixture defined by the user. Integration of Cantera with T-MATS extends the range of systems that may be modeled using the toolbox. In addition, the library of elements released with Cantera were developed using MATLAB native M-files, allowing for quicker prototyping of elements. This paper discusses how the new Cantera-based elements are created and provides examples for using T-MATS integrated with Cantera.
Zhang, Yu; Zhao, Jiyun; Wang, Peng; Skyllas-Kazacos, Maria; Xiong, Binyu; Badrinarayanan, Rajagopalan
2015-09-01
Electrical equivalent circuit models demonstrate excellent adaptability and simplicity in predicting the electrical dynamic response of the all-vanadium redox flow battery (VRB) system. However, only a few publications that focus on this topic are available. The paper presents a comprehensive equivalent circuit model of VRB for system level analysis. The least square method is used to identify both steady-state and dynamic characteristics of VRB. The inherent features of the flow battery such as shunt current, ion diffusion and pumping energy consumption are also considered. The proposed model consists of an open-circuit voltage source, two parasitic shunt bypass circuits, a 1st order resistor-capacitor network and a hydraulic circuit model. Validated with experimental data, the proposed model demonstrates excellent accuracy. The mean-error of terminal voltage and pump consumption are 0.09 V and 0.49 W respectively. Based on the proposed model, self-discharge and system efficiency are studied. An optimal flow rate which maximizes the system efficiency is identified. Finally, the dynamic responses of the proposed VRB model under step current profiles are presented. Variables such as SOC and stack terminal voltage can be provided.
Modeling, analysis and control system development for the Italian hydrogen house
Energy Technology Data Exchange (ETDEWEB)
Stewart, E.M. [Sandia National Laboratories, CA (United States); Institute for Energy and Environment, University of Strathclyde, Glasgow (United Kingdom); Lutz, A.E.; Keller, J.O. [Sandia National Laboratories, CA (United States); Schoenung, S. [Longitude 122 West Inc., CA (United States); Chiesa, M. [Catholic University of the Sacred Heart, Brescia (Italy); Fletcher, J.; Ault, G.; McDonald, J.; Cruden, A. [Institute for Energy and Environment, University of Strathclyde, Glasgow (United Kingdom)
2009-02-15
This paper provides an analysis of the ''Hydrogen from the Sun'' project at the ''Ecological House'' in northern Italy. The modeling and analysis work is being performed in conjunction with the International Energy Agency Hydrogen Implementing Agreement Annex 18: Integrated Systems Evaluation. A customized library of Matlab/Simulink component models is used to simulate the system and evaluate the hydrogen economics and energy production efficiencies. Two control algorithms are developed for the house using a fuzzy logic and an adaptive control strategy. The economic and steady state effects of these two strategies are compared as are the energy sources used to supply the energy demand of the house. The hydrogen production system consists of an electrolyzer, a photo-voltaic collector, and a battery, linked to both a metal hydride and high pressure gas storage system. The hydrogen supplies a fuel cell, which powers a residential estate. The analysis shows the contribution of the different system components to the overall efficiency and cost of hydrogen. However, the control systems presented also have a significant effect on the hydrogen and electricity cost. Reduction of these costs and an increase in system efficiency require optimal use of the hydrogen stored, as well as the optimized distribution of power supply from the generating components. The analysis shows the initial cost of hydrogen to be 9.36 $/kg, with electricity produced at 0.65 $/kWh using a fuzzy logic control system at an electrical efficiency of 50% (of the full hydrogen house system), based on the lower heating value of hydrogen. The result of using an active control strategy is presented. (author)
Ocean Model, Analysis and Prediction System version 3: operational global ocean forecasting
Brassington, Gary; Sandery, Paul; Sakov, Pavel; Freeman, Justin; Divakaran, Prasanth; Beckett, Duan
2017-04-01
The Ocean Model, Analysis and Prediction System version 3 (OceanMAPSv3) is a near-global (75S-75N; no sea-ice), uniform horizontal resolution (0.1°x0.1°), 51 vertical level ocean forecast system producing daily analyses and 7 day forecasts. This system was declared operational at the Bureau of Meteorology in April 2016 and subsequently upgraded to include ACCESS-G APS2 in June 2016 and finally ported to the Bureau's new supercomputer in Sep 2016. This system realises the original vision of the BLUElink projects (2003-2015) to provide global forecasts of the ocean geostrophic turbulence (eddies and fronts) in support of Naval operations as well as other national services. The analysis system has retained an ensemble-based optimal interpolation method with 144 stationary ensemble members derived from a multi-year hindcast. However, the BODAS code has been upgraded to a new code base ENKF-C. A new strategy for initialisation has been introduced leading to greater retention of analysis increments and reduced shock. The analysis cycle has been optimised for a 3-cycle system with 3 day observation windows retaining an advantage as a multi-cycle time-lagged ensemble. The sea surface temperature and sea surface height anomaly analysis errors in the Australian region are 0.34 degC and 6.2 cm respectively an improvement of 10% and 20% respectively over version 2. In addition, the RMSE of the 7 day forecast has lower error than the 1 day forecast from the previous system (version 2). International intercomparisons have shown that this system is comparable in performance with the two leading systems and is often the leading performer for surface temperature and upper ocean temperature. We present an overview of the system, the data assimilation and initialisation, demonstrate the performance and outline future directions.
Ultra-capacitors in power conversion systems analysis, modeling and design in theory and practice
Grbovic, Petar J
2014-01-01
Divided into five parts, this book is focused on ultra-capacitors and their applications in power conversion systems. It discusses ultra-capacitor analysis, modelling and module design from a macroscopic (application) perspective. It also describes power conversion applications, interface dc-dc converter design and entire conversion system design. Part One covers the background of energy storage technologies, with particular attention on state-of-the-art ultra-capacitor energy storage technologies. In Chapter four of this part, power conversion systems with integrated energy storage is discus
The Role of Systems Modeling for Sustainable Development Policy Analysis: the Case of Bio-Ethanol
Directory of Open Access Journals (Sweden)
Albert W. Chan
2004-12-01
Full Text Available A dynamic systems modeling technique has been developed to assess technologies according to the criterion of sustainability. In a case study, the potential contribution of bio-ethanol toward achieving Canada’s commitment to the Kyoto targets for greenhouse gas reductions is analyzed. The analysis concludes that, although bio-ethanol may help reduce greenhouse gas emissions, the technology by itself is insufficient to meet the Kyoto target. Applying the systems modeling approach to analyze sustainability helps highlight those policy issues that warrant more in-depth study. Although the systems model may not provide definitive answers, it raises relevant questions about physical constraints that might be encountered and estimates the extent to which sustainability targets may be met under various scenarios.
A MODEL OF HETEROGENEOUS DISTRIBUTED SYSTEM FOR FOREIGN EXCHANGE PORTFOLIO ANALYSIS
Directory of Open Access Journals (Sweden)
Dragutin Kermek
2006-06-01
Full Text Available The paper investigates the design of heterogeneous distributed system for foreign exchange portfolio analysis. The proposed model includes few separated and dislocated but connected parts through distributed mechanisms. Making system distributed brings new perspectives to performance busting where software based load balancer gets very important role. Desired system should spread over multiple, heterogeneous platforms in order to fulfil open platform goal. Building such a model incorporates different patterns from GOF design patterns, business patterns, J2EE patterns, integration patterns, enterprise patterns, distributed design patterns to Web services patterns. The authors try to find as much as possible appropriate patterns for planned tasks in order to capture best modelling and programming practices.
Aggarwal, Vinod
2002-10-01
This paper concerns itself with the beneficial effects of the Unified Modeling Language (UML), a nonproprietary object modeling standard, in specifying, visualizing, constructing, documenting, and communicating the model of a healthcare information system from the user's perspective. The author outlines the process of object-oriented analysis (OOA) using the UML and illustrates this with healthcare examples to demonstrate the practicality of application of the UML by healthcare personnel to real-world information system problems. The UML will accelerate advanced uses of object-orientation such as reuse technology, resulting in significantly higher software productivity. The UML is also applicable in the context of a component paradigm that promises to enhance the capabilities of healthcare information systems and simplify their management and maintenance.
Selic, Bran
2013-01-01
Modeling and Analysis of Real-Time and Embedded Systems with UML and MARTE explains how to apply the complex MARTE standard in practical situations. This approachable reference provides a handy user guide, illustrating with numerous examples how you can use MARTE to design and develop real-time and embedded systems and software. Expert co-authors Bran Selic and Sébastien Gérard lead the team that drafted and maintain the standard and give you the tools you need apply MARTE to overcome the limitations of cyber-physical systems. The functional sophistication required of modern cyber-physical
Munoz Fernandez, Michela Miche
2014-01-01
The potential of Model Model Systems Engineering (MBSE) using the Architecture Analysis and Design Language (AADL) applied to space systems will be described. AADL modeling is applicable to real-time embedded systems- the types of systems NASA builds. A case study with the Juno mission to Jupiter showcases how this work would enable future missions to benefit from using these models throughout their life cycle from design to flight operations.
Baldacchino, Tara; Cross, Elizabeth J.; Worden, Keith; Rowson, Jennifer
2016-01-01
Most physical systems in reality exhibit a nonlinear relationship between input and output variables. This nonlinearity can manifest itself in terms of piecewise continuous functions or bifurcations, between some or all of the variables. The aims of this paper are two-fold. Firstly, a mixture of experts (MoE) model was trained on different physical systems exhibiting these types of nonlinearities. MoE models separate the input space into homogeneous regions and a different expert is responsible for the different regions. In this paper, the experts were low order polynomial regression models, thus avoiding the need for high-order polynomials. The model was trained within a Bayesian framework using variational Bayes, whereby a novel approach within the MoE literature was used in order to determine the number of experts in the model. Secondly, Bayesian sensitivity analysis (SA) of the systems under investigation was performed using the identified probabilistic MoE model in order to assess how uncertainty in the output can be attributed to uncertainty in the different inputs. The proposed methodology was first tested on a bifurcating Duffing oscillator, and it was then applied to real data sets obtained from the Tamar and Z24 bridges. In all cases, the MoE model was successful in identifying bifurcations and different physical regimes in the data by accurately dividing the input space; including identifying boundaries that were not parallel to coordinate axes.
An Intelligent System for Modelling, Design and Analysis of Chemical Processes
DEFF Research Database (Denmark)
Gani, Rafiqul
ICAS, Integrated Computer Aided System, is a software that consists of a number of intelligent tools, which are very suitable, among others, for computer aided modelling, sustainable design of chemical and biochemical processes, and design-analysis of product-process monitoring systems. Each...... of these tools are characterized by a framework that follows an established work-flow and data-flow, developed to guide the user through the many steps of the problem solution process. At each, the specific tool knows which data, model and/or algorithm to use. The tool also provides analysis of the calculated...... results so that the user can make intelligent decisions to proceed to the next step. The tools contain in-house databases, especially designed to work in an integrated manner with tool specific ontology for efficient knowledge management. Examples highlighting the use of the tools willl be given, where...
Evaluating Domestic Hot Water Distribution System Options With Validated Analysis Models
Energy Technology Data Exchange (ETDEWEB)
Weitzel, E.; Hoeschele, M.
2014-09-01
A developing body of work is forming that collects data on domestic hot water consumption, water use behaviors, and energy efficiency of various distribution systems. A full distribution system developed in TRNSYS has been validated using field monitoring data and then exercised in a number of climates to understand climate impact on performance. This study builds upon previous analysis modelling work to evaluate differing distribution systems and the sensitivities of water heating energy and water use efficiency to variations of climate, load, distribution type, insulation and compact plumbing practices. Overall 124 different TRNSYS models were simulated. Of the configurations evaluated, distribution losses account for 13-29% of the total water heating energy use and water use efficiency ranges from 11-22%. The base case, an uninsulated trunk and branch system sees the most improvement in energy consumption by insulating and locating the water heater central to all fixtures. Demand recirculation systems are not projected to provide significant energy savings and in some cases increase energy consumption. Water use is most efficient with demand recirculation systems, followed by the insulated trunk and branch system with a central water heater. Compact plumbing practices and insulation have the most impact on energy consumption (2-6% for insulation and 3-4% per 10 gallons of enclosed volume reduced). The results of this work are useful in informing future development of water heating best practices guides as well as more accurate (and simulation time efficient) distribution models for annual whole house simulation programs.
Analysis, Modeling and Dynamic Optimization of 3D Time-of-Flight Imaging Systems
Schmidt, Mirko
2011-01-01
The present thesis is concerned with the optimization of 3D Time-of-Flight (ToF) imaging systems. These novel cameras determine range images by actively illuminating a scene and measuring the time until the backscattered light is detected. Depth maps are constructed from multiple raw images. Usually two of such raw images are acquired simultaneously using special correlating sensors. This thesis covers four main contributions: A physical sensor model is presented which enables the analysis a...
Hoyos Velasco, Carlos Ildefonso
2011-01-01
This Thesis is concerned with the modelling, analysis and control of novel mechatronic valve actuators for automotive systems, specifically, the control of the mechanical valves to intake and exhaust gases in Internal Combustion Engines (ICE). Scientific studies have shown that significant benefits in terms of engine efficiency and emissions can be obtained through the adoption of variable valve actuation. Current engine technology are based on the use of a mechanical driven camshaft, which i...
NREL's System Advisor Model Simplifies Complex Energy Analysis (Fact Sheet)
Energy Technology Data Exchange (ETDEWEB)
2015-01-01
NREL has developed a tool -- the System Advisor Model (SAM) -- that can help decision makers analyze cost, performance, and financing of any size grid-connected solar, wind, or geothermal power project. Manufacturers, engineering and consulting firms, research and development firms, utilities, developers, venture capital firms, and international organizations use SAM for end-to-end analysis that helps determine whether and how to make investments in renewable energy projects.
Message Structures: a modelling technique for information systems analysis and design
España, Sergio; Pastor, Óscar; Ruiz, Marcela
2011-01-01
Despite the increasing maturity of model-driven software development (MDD), some research challenges remain open in the field of information systems (IS). For instance, there is a need to improve modelling techniques so that they cover several development stages in an integrated way, and they facilitate the transition from analysis to design. This paper presents Message Structures, a technique for the specification of communicative interactions between the IS and organisational actors. This technique can be used both in the analysis stage and in the design stage. During analysis, it allows abstracting from the technology that will support the IS, and to complement business process diagramming techniques with the specification of the communicational needs of the organisation. During design, Message Structures serves two purposes: (i) it allows to systematically derive a specification of the IS memory (e.g. a UML class diagram), (ii) and it allows to reason the user interface design using abstract patterns. Thi...
Li, Xingfeng; Coyle, Damien; Maguire, Liam; McGinnity, Thomas M; Benali, Habib
2011-07-01
In this paper a model selection algorithm for a nonlinear system identification method is proposed to study functional magnetic resonance imaging (fMRI) effective connectivity. Unlike most other methods, this method does not need a pre-defined structure/model for effective connectivity analysis. Instead, it relies on selecting significant nonlinear or linear covariates for the differential equations to describe the mapping relationship between brain output (fMRI response) and input (experiment design). These covariates, as well as their coefficients, are estimated based on a least angle regression (LARS) method. In the implementation of the LARS method, Akaike's information criterion corrected (AICc) algorithm and the leave-one-out (LOO) cross-validation method were employed and compared for model selection. Simulation comparison between the dynamic causal model (DCM), nonlinear identification method, and model selection method for modelling the single-input-single-output (SISO) and multiple-input multiple-output (MIMO) systems were conducted. Results show that the LARS model selection method is faster than DCM and achieves a compact and economic nonlinear model simultaneously. To verify the efficacy of the proposed approach, an analysis of the dorsal and ventral visual pathway networks was carried out based on three real datasets. The results show that LARS can be used for model selection in an fMRI effective connectivity study with phase-encoded, standard block, and random block designs. It is also shown that the LOO cross-validation method for nonlinear model selection has less residual sum squares than the AICc algorithm for the study.
Institute of Scientific and Technical Information of China (English)
Yan ZHANG; Hongmei ZHENG; Bin CHEN; Naijin YANG
2013-01-01
An important and practical pattern of industrial symbiosis is rapidly developing:eco-industrial parks.In this study,we used social network analysis to study the network connectedness (i.e.,the proportion of the theoretical number of connections that had been achieved) and related attributes of these hybrid ecological and industrial symbiotic systems.This approach provided insights into details of the network's interior and analyzed the overall degree of connectedness and the relationships among the nodes within the network.We then characterized the structural attributes of the network and subnetwork nodes at two levels (core and periphery),thereby providing insights into the operational problems within each eco-industrial park.We chose ten typical ecoindustrial parks in China and around the world and compared the degree of network connectedness of these systems that resulted from exchanges of products,byproducts,and wastes.By analyzing the density and nodal degree,we determined the relative power and status of the nodes in these networks,as well as other structural attributes such as the core-periphery structure and the degree of sub-network connectedness.The results reveal the operational problems created by the structure of the industrial networks and provide a basis for improving the degree of completeness,thereby increasing their potential for sustainable development and enriching the methods available for the study of industrial symbiosis.
Dynamic performance analysis model of high-reliability EMS-Maglev system
Institute of Scientific and Technical Information of China (English)
FANG You-tong; YAO Ying-ying
2007-01-01
In this paper, a modified transient finite element (FE) algorithm for the performance analysis of magnetically levitated vehicles of electromagnetic type is presented. The algorithm incorporates the external power system and vehicle's movement equations into FE model of transient magnetic field computation directly. Sliding interface between stationary and moving region is used during the transient analysis. The periodic boundaries are implemented in an easy way to reduce the computation scale. It is proved that this method can be used for both electro-motional static and dynamic cases. The test of a transformer and an EMS-Maglev system reveals that the method generates reasonable results at very low computational costs comparing with the transient FE analysis.
Naseradinmousavi, Peiman
In this dissertation, the actuator-valve systems as a critical part of the automation system are analyzed. Using physics-based high fidelity modeling, this research provides a set of tools to help understand, predict, optimize, and control the real performance of these complex systems. The work carried out is expected to add to the suite of analytical and numerical tools that are essential for the development of highly automated ship systems. We present an accurate dynamic model, perform nonlinear analysis, and develop optimal design and operation for electromechanical valve systems. The mathematical model derived includes electromagnetics, fluid mechanics, and mechanical dynamics. Nondimensionalization has been carried out in order to reduce the large number of parameters to a few critical independent sets to help carry out a parametric analysis. The system stability analysis is then carried out with the aid of the tools from nonlinear dynamic analysis. This reveals that the system is unstable in a certain region of the parameter space. The system is also shown to exhibit crisis and transient chaotic responses. Smart valves are often operated under local power supply (for various mission-critical reasons) and need to consume as little energy as possible in order to ensure continued operability. The Simulated Annealing (SA) algorithm is utilized to optimize the actuation subsystem yielding the most efficient configuration from the point of view of energy consumption for two sets of design variables. The optimization is particularly important when the smart valves are used in a distributed network. Another aspect of optimality is more subtle and concerns optimal operation given a designed system. Optimal operation comes after the optimal design process to explore if there is any particular method of the valve operation that would yield the minimum possible energy used. The results of our model developed are also validated with the aid of an experimental setup
Energy Technology Data Exchange (ETDEWEB)
Morris, Edgar [Argonne National Lab. (ANL), Argonne, IL (United States)
2014-10-01
The Used Fuel Disposition Campaign (UFDC), as part of the DOE Office of Nuclear Energy’s (DOE-NE) Fuel Cycle Technology program (FCT) is investigating the disposal of high level radioactive waste (HLW) and spent nuclear fuela (SNF) in a variety of geologic media. The feasibility of disposing SNF and HLW in clay media has been investigated and has been shown to be promising [Ref. 1]. In addition the disposal of these wastes in clay media is being investigated in Belgium, France, and Switzerland. Thus, Argillaceous media is one of the environments being considered by UFDC. As identified by researchers at Sandia National Laboratory, potentially suitable formations that may exist in the U.S. include mudstone, clay, shale, and argillite formations [Ref. 1]. These formations encompass a broad range of material properties. In this report, reference to clay media is intended to cover the full range of material properties. This report presents the status of the development of a simulation model for evaluating the performance of generic clay media. The clay Generic Disposal System Model (GDSM) repository performance simulation tool has been developed with the flexibility to evaluate not only different properties, but different waste streams/forms and different repository designs and engineered barrier configurations/ materials that could be used to dispose of these wastes.
Application of the Periodic Average System Model in Dam Deformation Analysis
Directory of Open Access Journals (Sweden)
Yueqian Shen
2015-01-01
Full Text Available Dams are among the most important hydraulic engineering facilities used for water supply, flood control, and hydroelectric power. Monitoring of dams is crucial since deformation might have occurred. How to obtain the deformation information and then judge the safe conditions is the key and difficult problem in dam deformation monitoring field. This paper proposes the periodic average system model and creates the concept of “settlement activity” based on the dam deformation issue. Long-term deformation monitoring data is carried out in a pumped-storage power station, this model combined with settlement activity is used to make the single point deformation analysis, and then the whole settlement activity profile is drawn by clustering analysis. Considering the cumulative settlement value of every point, the dam deformation trend is analyzed in an intuitive effect way. The analysis mode of combined single point with multipoints is realized. The results show that the key deformation information of the dam can be easily grasped by the application of the periodic average system model combined with the distribution diagram of settlement activity. And, above all, the ideas of this research provide an effective method for dam deformation analysis.
Uncertainty Modeling for Robustness Analysis of Control Upset Prevention and Recovery Systems
Belcastro, Christine M.; Khong, Thuan H.; Shin, Jong-Yeob; Kwatny, Harry; Chang, Bor-Chin; Balas, Gary J.
2005-01-01
Formal robustness analysis of aircraft control upset prevention and recovery systems could play an important role in their validation and ultimate certification. Such systems (developed for failure detection, identification, and reconfiguration, as well as upset recovery) need to be evaluated over broad regions of the flight envelope and under extreme flight conditions, and should include various sources of uncertainty. However, formulation of linear fractional transformation (LFT) models for representing system uncertainty can be very difficult for complex parameter-dependent systems. This paper describes a preliminary LFT modeling software tool which uses a matrix-based computational approach that can be directly applied to parametric uncertainty problems involving multivariate matrix polynomial dependencies. Several examples are presented (including an F-16 at an extreme flight condition, a missile model, and a generic example with numerous crossproduct terms), and comparisons are given with other LFT modeling tools that are currently available. The LFT modeling method and preliminary software tool presented in this paper are shown to compare favorably with these methods.
Institute of Scientific and Technical Information of China (English)
CHANG Hong; RU Feng; XUE Jun-yi
2006-01-01
In this paper, data streams are classified into four types conforming to a standardized infrastructure of communication networks for a substation automation system (SAS) based on IEC61850 system. The data exchanged on the net are demonstrated to be stochastic according to investigation on the Ethernet communication principles. Four generalized stochastic Petri nets (GSPN) based models for performance analysis of communication networks of IEC61850 system are developed based on the three-level structure of SAS, different time requirements of the four data streams and different networks topology for different voltage level. The GSPN-based model associated with immediate and exponential transitions is proven to be theoretically isomorphic with Markov chain; hence we apply the mathematic methods of performance evaluation contained in Markov chain to the GSPN models proposed. The computer simulation of the model including only sample value data streams shows that it can meet performance evaluation needs of communication networks of IEC61850 system. Further researches should be focused on the performance of the other three models to explain clear how those different data streams are interrelated to and interact on each other.
Amir Farbin
The ATLAS Analysis Model is a continually developing vision of how to reconcile physics analysis requirements with the ATLAS offline software and computing model constraints. In the past year this vision has influenced the evolution of the ATLAS Event Data Model, the Athena software framework, and physics analysis tools. These developments, along with the October Analysis Model Workshop and the planning for CSC analyses have led to a rapid refinement of the ATLAS Analysis Model in the past few months. This article introduces some of the relevant issues and presents the current vision of the future ATLAS Analysis Model. Event Data Model The ATLAS Event Data Model (EDM) consists of several levels of details, each targeted for a specific set of tasks. For example the Event Summary Data (ESD) stores calorimeter cells and tracking system hits thereby permitting many calibration and alignment tasks, but will be only accessible at particular computing sites with potentially large latency. In contrast, the Analysis...
STABILITY ANALYSIS OF A COMPUTER VIRUS PROPAGATION MODEL WITH ANTIDOTE IN VULNERABLE SYSTEM
Institute of Scientific and Technical Information of China (English)
Nguyen Huu KHANH; Nguyen Bich HUY
2016-01-01
We study a proposed model describing the propagation of computer virus in the network with antidote in vulnerable system. Mathematical analysis shows that dynamics of the spread of computer viruses is determined by the threshold R0. If R0 ≤ 1, the virus-free equilibrium is globally asymptotically stable, and if R0 >1, the endemic equilibrium is globally asymptotically stable. Lyapunov functional method as well as geometric approach are used for proving the global stability of equilibria. A numerical investigation is carried out to confirm the analytical results. Through parameter analysis, some effective strategies for eliminating viruses are suggested.
Directory of Open Access Journals (Sweden)
TEODORA VĂTUIU
2014-10-01
Full Text Available Study of organizational activity and highlighting problem situations that require specific solutions, require a detailed analysis of the models defined for the real system of the economic companies, regarded not as a sum of assets, but as organizations in which there are activities related into processes. In addition to the usual approach of using modeling languages in the development of information systems, in this paper we intend to present some examples that demonstrate the usefulness of a standard modeling language (UML to analyze organizational activities and to report problem situations that may occur in data management registered on primary documents or in processes that bring together activities. Examples that have been focused on a travel agency can be extrapolated to any other organization, and the diagrams can be used in different contexts, depending on the complexity of the activities identified.
Quasimodes instability analysis of uncertain asymmetric rotor system based on 3D solid element model
Zuo, Yanfei; Wang, Jianjun; Ma, Weimeng
2017-03-01
Uncertainties are considered in the equation of motion of an asymmetric rotor system. Based on Hill's determinant method, quasimodes stability analysis with uncertain parameters is used to get stochastic boundaries of unstable regions. Firstly, A 3D finite element rotor model was built in rotating frame with four parameterized coefficients, which is assumed as random parameters representing the uncertainties existing in the rotor system. Then the influences of uncertain coefficients on the distribution of the unstable region boundaries are analyzed. The results show that uncertain parameters have various influences on the size, boundary and number of unstable regions. At last, the statistic results of the minimum and maximum spin speeds of unstable regions were got by Monte Carlo simulation. The used method is suitable for real engineering rotor system, because arbitrary configuration of rotors can be modeled by 3D finite element.
Energy Technology Data Exchange (ETDEWEB)
Schlake, Jan Christoph
2011-07-01
The publication addresses engineers and scientists working on systems with locally distributed parameters. Using the exemplary systems of resin transfer molding, direct methanol fuel cell, and unilaterally fixed beam, it is shown how a system analysis and optimisation can be carried out on the basis of a description of the dynamics using partial differential equations. After local discretisation using the mortar element method, which is particularly suited for complex fields, a comparatively low order approximation model is generated. The approximation model provides a basis for constructive geometry optimisation of the field and for application of well-tried controller design methods. Dynamic pre-filters and local outlet filters reduce the spillover effect and permit the definition of an eigenfunction. [German] Die vorliegende Arbeit richtet sich an Ingenieure und Wissenschaftler, die sich mit der Behandlung von Systemen mit oertlich verteilten Parametern beschaeftigen. Anhand der Beispielsysteme Resin-Transfer-Molding, Direkt-Methanol-Brennstoffzelle und einseitig eingespannter Doppelbalken wird gezeigt, wie ausgehend von einer Beschreibung der Dynamik durch partielle Differentialgleichungen eine Systemanalyse und anschliessende Systemoptimierung durchgefuehrt werden kann. Nach einer Ortsdiskretisierung mittels der besonders fuer komplexe Gebiete geeigneten Mortar-Elemente-Methode wird ein Approximationsmodell vergleichsweise niedriger Ordnung erzeugt. Dieses bildet zum einen die Basis fuer eine konstruktive Geometrieoptimierung des Gebietes und zum anderen die Moeglichkeit zur Anwendung bekannter Reglerentwurfsverfahren. Hierbei werden durch Verwendung von dynamischen Vorfiltern und oertlichem Ausgangsfiltern die Auswirkungen des Spillover Effektes reduziert und eine Vorgabe der Eigenfunktion ermoeglicht.
Generalized Tensor Analysis Model for Multi-Subcarrier Analog Optical Systems
DEFF Research Database (Denmark)
Zhao, Ying; Yu, Xianbin; Zheng, Xiaoping
2011-01-01
We propose and develop a general tensor analysis framework for a subcarrier multiplex analog optical fiber link for applications in microwave photonics. The goal of this work is to construct an uniform method to address nonlinear distortions of a discrete frequency transmission system. We employ ...... a study of two multi-subcarrier systems with detailed performance discussions. We believe the tensor model provides us not only a consolidated notation, but also an alternative numerical approach to effectively analyze multi-subcarrier analog optical systems.......We propose and develop a general tensor analysis framework for a subcarrier multiplex analog optical fiber link for applications in microwave photonics. The goal of this work is to construct an uniform method to address nonlinear distortions of a discrete frequency transmission system. We employ...... details compared with series-based approaches by hiding the underlying multi-fold summation and index operation. The integrity of the proposed methodology is validated by investigating the classical intensity modulated system. Furthermore, to give an application model of the tensor formalism, we make...
Rasch modeling and confirmatory factor analysis of the systemizing quotient-revised (SQ-R) scale.
Allison, Carrie; Baron-Cohen, Simon; Stone, Mark H; Muncer, Steven J
2015-01-01
This study assessed the dimensionality of the Systemizing Quotient-Revised (SQ-R), a measure of how strong a person's interest is in systems, using two statistical approaches: Rasch modeling and Confirmatory Factor Analysis (CFA). Participants included N = 675 with an autism spectrum condition (ASC), N = 1369 family members of people with ASC, and N = 2014 typical controls. Data were applied to the Rasch model (Rating Scale) using WINSTEPS. The data fit the Rasch model quite well lending support to the idea that systemizing could be seen as unidimensional. Reliability estimates were .99 for items and .92 for persons. A CFA parceling approach confirmed that a unidimensional model fit the data. There was, however, differential functioning by sex in some of these items. An abbreviated 44-item version of the scale, consisting of items without differential item functioning by sex was developed. This shorter scale also was tested from a Rasch perspective and confirmed through CFA. All measures showed differences on total scale scores between those participants with and without ASC (d = 0.71, p < .005), and between sexes (d = 0.53, p < .005). We conclude that the SQ-R is an appropriate measure of systemizing which can be measured along a single dimension.
Chen, Aijie; Feng, Xiaoli; Zhang, Yanli; Liu, Ruoyu; Shao, Longquan
2015-01-01
To investigate the stress distribution in a maxillary canine restored with each of four different post systems at different levels of alveolar bone loss. Two-dimensional finite element analysis (FEA) was performed by modeling a severely damaged canine with four different post systems: CAD/CAM zirconia, CAD/CAM glass fiber, cast titanium, and cast gold. A force of 100 N was applied to the crown, and the von Mises stresses were obtained. FEA revealed that the CAD/CAM zirconia post system produced the lowest maximum von Mises stress in the dentin layer at 115.8 MPa, while the CAD/CAM glass fiber post produced the highest stress in the dentin at 518.2 MPa. For a severely damaged anterior tooth, a zirconia post system is the best choice while a cast gold post ranks second. The CAD/CAM glass fiber post is least recommended in terms of stress level in the dentin.
Modeling And Experimental Analysis Of Generator In Vapour Absorption Refrigeration System
Directory of Open Access Journals (Sweden)
Christy V Vazhappilly
2013-09-01
Full Text Available A breadboard prototype of an absorption system for refrigeration using heat from the exhaust-gases is to be designed, built and tested. In the commercial vapour absorption refrigeration system a heating coil generator system has been employed to vaporize the ammonia efrigerant. In the present work, the heating coil generator system has been replaced by the frame plate type heat exchanger. The exhaust gases from the IC engine have been utilized to vaporize the ammonia refrigerant. The available heat in the exhaust gases has to be estimated based on actual I.C-Engine driving cycles. The frame plate type heat exchanger has to be modeled and flow analysis inside the heat exchanger has to be analyzed. In addition, the recoverable energy of the exhaust gases is to be analyzed for representative Internal Combustion Engine.
Next-Generation Climate Modeling Science Challenges for Simulation, Workflow and Analysis Systems
Koch, D. M.; Anantharaj, V. G.; Bader, D. C.; Krishnan, H.; Leung, L. R.; Ringler, T.; Taylor, M.; Wehner, M. F.; Williams, D. N.
2016-12-01
We will present two examples of current and future high-resolution climate-modeling research that are challenging existing simulation run-time I/O, model-data movement, storage and publishing, and analysis. In each case, we will consider lessons learned as current workflow systems are broken by these large-data science challenges, as well as strategies to repair or rebuild the systems. First we consider the science and workflow challenges to be posed by the CMIP6 multi-model HighResMIP, involving around a dozen modeling groups performing quarter-degree simulations, in 3-member ensembles for 100 years, with high-frequency (1-6 hourly) diagnostics, which is expected to generate over 4PB of data. An example of science derived from these experiments will be to study how resolution affects the ability of models to capture extreme-events such as hurricanes or atmospheric rivers. Expected methods to transfer (using parallel Globus) and analyze (using parallel "TECA" software tools) HighResMIP data for such feature-tracking by the DOE CASCADE project will be presented. A second example will be from the Accelerated Climate Modeling for Energy (ACME) project, which is currently addressing challenges involving multiple century-scale coupled high resolution (quarter-degree) climate simulations on DOE Leadership Class computers. ACME is anticipating production of over 5PB of data during the next 2 years of simulations, in order to investigate the drivers of water cycle changes, sea-level-rise, and carbon cycle evolution. The ACME workflow, from simulation to data transfer, storage, analysis and publication will be presented. Current and planned methods to accelerate the workflow, including implementing run-time diagnostics, and implementing server-side analysis to avoid moving large datasets will be presented.
Xu, Lei; Zhai, Wanming
2017-10-01
This paper devotes to develop a computational model for stochastic analysis and reliability assessment of vehicle-track systems subject to earthquakes and track random irregularities. In this model, the earthquake is expressed as non-stationary random process simulated by spectral representation and random function, and the track random irregularities with ergodic properties on amplitudes, wavelengths and probabilities are characterized by a track irregularity probabilistic model, and then the number theoretical method (NTM) is applied to effectively select representative samples of earthquakes and track random irregularities. Furthermore, a vehicle-track coupled model is presented to obtain the dynamic responses of vehicle-track systems due to the earthquakes and track random irregularities at time-domain, and the probability density evolution method (PDEM) is introduced to describe the evolutionary process of probability from excitation input to response output by assuming the vehicle-track system as a probabilistic conservative system, which lays the foundation on reliability assessment of vehicle-track systems. The effectiveness of the proposed model is validated by comparing to the results of Monte-Carlo method from statistical viewpoint. As an illustrative example, the random vibrations of a high-speed railway vehicle running on the track slabs excited by lateral seismic waves and track random irregularities are analyzed, from which some significant conclusions can be drawn, e.g., track irregularities will additionally promote the dynamic influence of earthquakes especially on maximum values and dispersion degree of responses; the characteristic frequencies or frequency ranges respectively governed by earthquakes and track random irregularities are greatly different, moreover, the lateral seismic waves will dominate or even change the characteristic frequencies of system responses of some lateral dynamic indices at low frequency.
Thomaseth, K
1994-02-14
Software is presented for automatic generation of first-order ordinary differential equations (ODE) that arise from lumped parameter representations of metabolic and pharmacokinetic systems. The definition of system structures is accomplished by fractional transfer rates between state variables, together with input/output equations and initial conditions of state variables. General non-linear mathematical expressions can be assigned to all structure definition items. The software parses and interprets the system definitions and generates symbolically the mathematical expression of the model's set of ODE. In addition, symbolic derivatives of state equations are determined with respect to model parameters, state variables and external inputs. These derivatives represent the constituents of systems of sensitivity-differential and adjoint-differential equations that arise in identification and optimal control problems. Finally, output routines generate source code that, once compiled and linked to simulation programs, allows efficient numerical integration of the system of ODE. This software has been developed in PROLOG on Macintosh computers and has been extensively used with the programming environment MATLAB. Possible applications of this software include model building, sensitivity analysis, identification, optimal experiment design and numerical solution of optimal control problems.
Tav4SB: integrating tools for analysis of kinetic models of biological systems
Directory of Open Access Journals (Sweden)
Rybiński Mikołaj
2012-04-01
Full Text Available Abstract Background Progress in the modeling of biological systems strongly relies on the availability of specialized computer-aided tools. To that end, the Taverna Workbench eases integration of software tools for life science research and provides a common workflow-based framework for computational experiments in Biology. Results The Taverna services for Systems Biology (Tav4SB project provides a set of new Web service operations, which extend the functionality of the Taverna Workbench in a domain of systems biology. Tav4SB operations allow you to perform numerical simulations or model checking of, respectively, deterministic or stochastic semantics of biological models. On top of this functionality, Tav4SB enables the construction of high-level experiments. As an illustration of possibilities offered by our project we apply the multi-parameter sensitivity analysis. To visualize the results of model analysis a flexible plotting operation is provided as well. Tav4SB operations are executed in a simple grid environment, integrating heterogeneous software such as Mathematica, PRISM and SBML ODE Solver. The user guide, contact information, full documentation of available Web service operations, workflows and other additional resources can be found at the Tav4SB project’s Web page: http://bioputer.mimuw.edu.pl/tav4sb/. Conclusions The Tav4SB Web service provides a set of integrated tools in the domain for which Web-based applications are still not as widely available as for other areas of computational biology. Moreover, we extend the dedicated hardware base for computationally expensive task of simulating cellular models. Finally, we promote the standardization of models and experiments as well as accessibility and usability of remote services.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Polarized magnetic system has a series of features, such as small volume, light weight, low power consumption, high sensitivity, quick movement and so on, widely used in the products of the military aerospace electromagnetic relay. The typical polarized magnetic system has mainly four structures and its simplified equivalent magnetic circuits model is the base of the design of the electromagnetic relay with permanent magnet. In the past, the analysis method that people used was difficult to build the unified mathematical models, which divided the work gap magnetic flux into "permanent magnet flux" and "electromagnetic flux". Based on the analysis method of the work gap magnetic voltage, this paper founds the unified mathematical model of the polarized magnetic system and divides the attractive torque into permanent magnet torque, polarized torque and electromagnetic torque through the energy balance formula. It analyses the influence of permanent magnet sizes on permanent magnet torque, polarized torque and electromagnetic torque through the energy balance formula and the conclusions can direct the design of aerospace electromagnetic relay with permanent magnet.
The Aviation System Analysis Capability Air Carrier Cost-Benefit Model
Gaier, Eric M.; Edlich, Alexander; Santmire, Tara S.; Wingrove, Earl R.., III
1999-01-01
To meet its objective of assisting the U.S. aviation industry with the technological challenges of the future, NASA must identify research areas that have the greatest potential for improving the operation of the air transportation system. Therefore, NASA is developing the ability to evaluate the potential impact of various advanced technologies. By thoroughly understanding the economic impact of advanced aviation technologies and by evaluating how the new technologies will be used in the integrated aviation system, NASA aims to balance its aeronautical research program and help speed the introduction of high-leverage technologies. To meet these objectives, NASA is building the Aviation System Analysis Capability (ASAC). NASA envisions ASAC primarily as a process for understanding and evaluating the impact of advanced aviation technologies on the U.S. economy. ASAC consists of a diverse collection of models and databases used by analysts and other individuals from the public and private sectors brought together to work on issues of common interest to organizations in the aviation community. ASAC also will be a resource available to the aviation community to analyze; inform; and assist scientists, engineers, analysts, and program managers in their daily work. The ASAC differs from previous NASA modeling efforts in that the economic behavior of buyers and sellers in the air transportation and aviation industries is central to its conception. Commercial air carriers, in particular, are an important stakeholder in this community. Therefore, to fully evaluate the implications of advanced aviation technologies, ASAC requires a flexible financial analysis tool that credibly links the technology of flight with the financial performance of commercial air carriers. By linking technical and financial information, NASA ensures that its technology programs will continue to benefit the user community. In addition, the analysis tool must be capable of being incorporated into the
Global sensitivity analysis and uncertainties in SEA models of vibroacoustic systems
Christen, Jean-Loup; Ichchou, Mohamed; Troclet, Bernard; Bareille, Olivier; Ouisse, Morvan
2017-06-01
The effect of parametric uncertainties on the dispersion of Statistical Energy Analysis (SEA) models of structural-acoustic coupled systems is studied with the Fourier analysis sensitivity test (FAST) method. The method is firstly applied to an academic example representing a transmission suite, then to a more complex industrial structure from the space industry. Two sets of parameters are considered, namely error on the SEA model's coefficients, or directly the engineering parameters. The first case is an intrusive approach, but enables to identify the dominant phenomena taking place in a given configuration. The second is non-intrusive and appeals more to engineering considerations, by studying the effect of input parameters such as geometry or material characteristics on the SEA outputs. A study of the distribution of results in each frequency band with the same sampling shows some interesting features, such as bimodal repartitions in some ranges.
Waszak, Martin R.; Barthelemy, Jean-Francois; Jones, Kenneth M.; Silcox, Richard J.; Silva, Walter A.; Nowaczyk, Ronald H.
1998-01-01
Multidisciplinary analysis and design is inherently a team activity due to the variety of required expertise and knowledge. As a team activity, multidisciplinary research cannot escape the issues that affect all teams. The level of technical diversity required to perform multidisciplinary analysis and design makes the teaming aspects even more important. A study was conducted at the NASA Langley Research Center to develop a model of multidiscipline teams that can be used to help understand their dynamics and identify key factors that influence their effectiveness. The study sought to apply the elements of systems thinking to better understand the factors, both generic and Langley-specific, that influence the effectiveness of multidiscipline teams. The model of multidiscipline research teams developed during this study has been valuable in identifying means to enhance team effectiveness, recognize and avoid problem behaviors, and provide guidance for forming and coordinating multidiscipline teams.
Sensor selection of helicopter transmission systems based on physical model and sensitivity analysis
Institute of Scientific and Technical Information of China (English)
Lyu Kehong; Tan Xiaodong; Liu Guanjun; Zhao Chenxu
2014-01-01
In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on physical model and sensitivity analysis. Firstly, a physical model of tooth damage and mesh stiffness is built. Secondly, some effective condition indicators (CIs) are presented, and the optimal CIs set is selected by comparing their test statistics according to Mann-Kendall test. Afterwards, the selected CIs are used to generate a health indicator (HI) through sen slop estimator. Then, the sensors are selected according to the monotonic relevance and sensitivity to the damage levels. Finally, the proposed method is verified by the simulation and experimental data. The results show that the approach can provide a guide for health monitor-ing of helicopter transmission systems, and it is effective to reduce the test cost and improve the system’s reliability.
Modelling and analysis of offshore energy systems on North Sea oil and gas platforms
DEFF Research Database (Denmark)
Nguyen, Tuong-Van; Elmegaard, Brian; Pierobon, Leonardo
2012-01-01
export, and power generation. In this paper, a generic model of a North Sea oil and gas platform is described and the most thermodynamically inefficient processes are identified by performing an exergy analysis. Models and simulations are built and run with the tools Aspen Plus R, DNA and Aspen HYSYS R......Offshore processes are associated with significant energy consumption and large CO2 emissions. Conventional North Sea oil and gas facilities include the following operations: crude oil separation, gas compression and purification, wastewater treatment, gas lifting, seawater injection, oil and gas...... and gas processing system, consuming 4-6 MW and 3-7 MW respectively, while the power generation system alone is responsible for 54-63 MW....
Sensor selection of helicopter transmission systems based on physical model and sensitivity analysis
Directory of Open Access Journals (Sweden)
Lyu Kehong
2014-06-01
Full Text Available In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on physical model and sensitivity analysis. Firstly, a physical model of tooth damage and mesh stiffness is built. Secondly, some effective condition indicators (CIs are presented, and the optimal CIs set is selected by comparing their test statistics according to Mann–Kendall test. Afterwards, the selected CIs are used to generate a health indicator (HI through sen slop estimator. Then, the sensors are selected according to the monotonic relevance and sensitivity to the damage levels. Finally, the proposed method is verified by the simulation and experimental data. The results show that the approach can provide a guide for health monitoring of helicopter transmission systems, and it is effective to reduce the test cost and improve the system’s reliability.
Porter, Ian Edward
A nuclear reactor systems code has the ability to model the system response in an accident scenario based on known initial conditions at the onset of the transient. However, there has been a tendency for these codes to lack the detailed thermo-mechanical fuel rod response models needed for accurate prediction of fuel rod failure. This proposed work will couple today's most widely used steady-state (FRAPCON) and transient (FRAPTRAN) fuel rod models with a systems code TRACE for best-estimate modeling of system response in accident scenarios such as a loss of coolant accident (LOCA). In doing so, code modifications will be made to model gamma heating in LWRs during steady-state and accident conditions and to improve fuel rod thermal/mechanical analysis by allowing axial nodalization of burnup-dependent phenomena such as swelling, cladding creep and oxidation. With the ability to model both burnup-dependent parameters and transient fuel rod response, a fuel dispersal study will be conducted using a hypothetical accident scenario under both PWR and BWR conditions to determine the amount of fuel dispersed under varying conditions. Due to the fuel fragmentation size and internal rod pressure both being dependent on burnup, this analysis will be conducted at beginning, middle and end of cycle to examine the effects that cycle time can play on fuel rod failure and dispersal. Current fuel rod and system codes used by the Nuclear Regulatory Commission (NRC) are compilations of legacy codes with only commonly used light water reactor materials, Uranium Dioxide (UO2), Mixed Oxide (U/PuO 2) and zirconium alloys. However, the events at Fukushima Daiichi and Three Mile Island accident have shown the need for exploration into advanced materials possessing improved accident tolerance. This work looks to further modify the NRC codes to include silicon carbide (SiC), an advanced cladding material proposed by current DOE funded research on accident tolerant fuels (ATF). Several
Modeling Regional Dynamics of Human-Rangifer Systems: a Framework for Comparative Analysis
Directory of Open Access Journals (Sweden)
Matthew Berman
2013-12-01
Full Text Available Theoretical models of interaction between wild and domestic reindeer (Rangifer tarandus; caribou in North America can help explain observed social-ecological dynamics of arctic hunting and husbandry systems. Different modes of hunting and husbandry incorporate strategies to mitigate effects of differing patterns of environmental uncertainty. Simulations of simple models of harvested wild and domestic herds with density-dependent recruitment show that random environmental variation produces cycles and crashes in populations that would quickly stabilize at a steady state with nonrandom parameters. Different husbandry goals lead to radically different long-term domestic herd sizes. Wild and domestic herds are typically ecological competitors but social complements. Hypothesized differences in ecological competition and diverse human livelihoods are explored in dynamic social-ecological models in which domestic herds competitively interact with wild herds. These models generate a framework for considering issues in the evolution of Human-Rangifer Systems, such as state-subsidized herding and the use of domestic herds for transportation support in hunting systems. Issues considered include the role of geographic factors, markets for Rangifer products, state-subsidized herding, effects of changes in husbandry goals on fate of wild herds, and how environmental shocks, herd population cycles, and policy shifts might lead to system state changes. The models also suggest speculation on the role of geographic factors in the failure of reindeer husbandry to take hold in the North American Arctic. The analysis concludes with suggested empirical strategies for estimating parameters of the model for use in comparative studies across regions of the Arctic.
Spardy, Lucy E; Markin, Sergey N; Shevtsova, Natalia A; Prilutsky, Boris I; Rybak, Ilya A; Rubin, Jonathan E
2011-12-01
In this paper we analyze a closed loop neuromechanical model of locomotor rhythm generation. The model is composed of a spinal central pattern generator (CPG) and a single-joint limb, with CPG outputs projecting via motoneurons to muscles that control the limb and afferent signals from the muscles feeding back to the CPG. In a preceding companion paper (Spardy et al 2011 J. Neural Eng. 8 065003), we analyzed how the model generates oscillations in the presence or absence of feedback, identified curves in a phase plane associated with the limb that signify where feedback levels induce phase transitions within the CPG, and explained how increasing feedback strength restores oscillations in a model representation of spinal cord injury; from these steps, we derived insights about features of locomotor rhythms in several scenarios and made predictions about rhythm responses to various perturbations. In this paper, we exploit our analytical observations to construct a reduced model that retains important characteristics from the original system. We prove the existence of an oscillatory solution to the reduced model using a novel version of a Melnikov function, adapted for discontinuous systems, and also comment on the uniqueness and stability of this solution. Our analysis yields a deeper understanding of how the model must be tuned to generate oscillations and how the details of the limb dynamics shape overall model behavior. In particular, we explain how, due to the feedback signals in the model, changes in the strength of a tonic supra-spinal drive to the CPG yield asymmetric alterations in the durations of different locomotor phases, despite symmetry within the CPG itself.
LaRocca, Sarah; Hassel, Henrik; Guikema, Seth
2013-01-01
Critical infrastructure systems must be both robust and resilient in order to ensure the functioning of society. To improve the performance of such systems, we often use risk and vulnerability analysis to find and address system weaknesses. A critical component of such analyses is the ability to accurately determine the negative consequences of various types of failures in the system. Numerous mathematical and simulation models exist which can be used to this end. However, there are relatively few studies comparing the implications of using different modeling approaches in the context of comprehensive risk analysis of critical infrastructures. Thus in this paper, we suggest a classification of these models, which span from simple topologically-oriented models to advanced physical flow-based models. Here, we focus on electric power systems and present a study aimed at understanding the tradeoffs between simplicity and fidelity in models used in the context of risk analysis. Specifically, the purpose of this pa...
1991-01-01
International Institute for Applied Systems Analysis in...Environment Program, International Institute for Applied Systems Analysis , and Cornell University (Loucks et al. 1989 and 1990). IRIS simulates a water... International Institute for Applied Systems Analysis , Laxenburg, Austria, 1982. Kennington, J.L., and R.V. Helgason, Algorithms for
A NEW AIR CONDITIONING SYSTEM FAN MODEL BASED ON NUMERICAL ANALYSIS
Directory of Open Access Journals (Sweden)
Nabil Nassif
2014-01-01
Full Text Available A large portion of energy use in buildings is attributed to air movement devices. Accurate estimation of fan performance is a key element in maximizing fan efficiency. This study proposes a new fan model that can be used in several applications such as optimization and fault detection and can also be incorporated into any commercial building models. The model uses a numerical analysis based on an interpolation technique for the data generated by basic fan laws. It can use any two variables among all four variables of airflow rate, total fan pressure, speed and power as inputs or outputs. Another advantage of this model is the flexibility of using any size of data for calibration, obtained either from manufacturers or field measured data. The model was tested for accuracy using two different manufacturers’ data of roof top unit packages with capacity ranging from 2 to 20 tons. Furthermore, the model was evaluated and tested on an actual VAV system using three months’ worth of measured data. The results show that the model can provide accurate estimation with the Coefficient of Variance (CV less than 2% and it can be used for several applications.
Khalilpour, Rajab
2011-08-12
The modeling and optimal design/operation of gas membranes for postcombustion carbon capture (PCC) is presented. A systematic methodology is presented for analysis of membrane systems considering multicomponent flue gas with CO 2 as target component. Simplifying assumptions is avoided by namely multicomponent flue gas represented by CO 2/N 2 binary mixture or considering the co/countercurrent flow pattern of hollow-fiber membrane system as mixed flow. Optimal regions of flue gas pressures and membrane area were found within which a technoeconomical process system design could be carried out. High selectivity was found to not necessarily have notable impact on PCC membrane performance, rather, a medium selectivity combined with medium or high permeance could be more advantageous. © 2011 American Institute of Chemical Engineers (AIChE).
Energy Technology Data Exchange (ETDEWEB)
Blackwell, D.D.
1998-04-25
During this first quarter of the second year of the contract activity has involved several different tasks. The author has continued to work on three tasks most intensively during this quarter: the task of implementing the data base for geothermal system temperature-depth, the maintenance of the WWW site with the heat flow and gradient data base, and finally the development of a modeling capability for analysis of the geothermal system exploration data. The author has completed the task of developing a data base template for geothermal system temperature-depth data that can be used in conjunction with the regional data base that he had already developed and is now implementing it. Progress is described.
Drysdale, Alan; Thomas, Mark; Fresa, Mark; Wheeler, Ray
1992-01-01
Controlled Ecological Life Support System (CELSS) technology is critical to the Space Exploration Initiative. NASA's Kennedy Space Center has been performing CELSS research for several years, developing data related to CELSS design. We have developed OCAM (Object-oriented CELSS Analysis and Modeling), a CELSS modeling tool, and have used this tool to evaluate CELSS concepts, using this data. In using OCAM, a CELSS is broken down into components, and each component is modeled as a combination of containers, converters, and gates which store, process, and exchange carbon, hydrogen, and oxygen on a daily basis. Multiple crops and plant types can be simulated. Resource recovery options modeled include combustion, leaching, enzyme treatment, aerobic or anaerobic digestion, and mushroom and fish growth. Results include printouts and time-history graphs of total system mass, biomass, carbon dioxide, and oxygen quantities; energy consumption; and manpower requirements. The contributions of mass, energy, and manpower to system cost have been analyzed to compare configurations and determine appropriate research directions.
Drysdale, Alan; Thomas, Mark; Fresa, Mark; Wheeler, Ray
1992-01-01
Controlled Ecological Life Support System (CELSS) technology is critical to the Space Exploration Initiative. NASA's Kennedy Space Center has been performing CELSS research for several years, developing data related to CELSS design. We have developed OCAM (Object-oriented CELSS Analysis and Modeling), a CELSS modeling tool, and have used this tool to evaluate CELSS concepts, using this data. In using OCAM, a CELSS is broken down into components, and each component is modeled as a combination of containers, converters, and gates which store, process, and exchange carbon, hydrogen, and oxygen on a daily basis. Multiple crops and plant types can be simulated. Resource recovery options modeled include combustion, leaching, enzyme treatment, aerobic or anaerobic digestion, and mushroom and fish growth. Results include printouts and time-history graphs of total system mass, biomass, carbon dioxide, and oxygen quantities; energy consumption; and manpower requirements. The contributions of mass, energy, and manpower to system cost have been analyzed to compare configurations and determine appropriate research directions.
Directory of Open Access Journals (Sweden)
Jürgen Staadt
2015-06-01
Full Text Available Organizations that find themselves within a problematic situation connected with cultural issues such as politics and power require adaptable research and corresponding modeling approaches so as to grasp the arrangements of that situation and their impact on the organizational development. This article originates from an insider-ethnographic intervention into the problematic situation of the leading public housing provider in Luxembourg. Its aim is to describe how the more action-oriented cultural analysis of soft systems methodology and the theory-driven configuration model of organizational culture are mutually beneficial rather than contradictory. The data collected between 2007 and 2013 were analyzed manually as well as by means of ATLAS.ti. Results demonstrate that the cultural analysis enables an in-depth understanding of the power-laden environment within the organization bringing about the so-called “socio-political system” and that the configuration model makes it possible to depict the influence of that system on the whole organization. The overall research approach thus contributes toward a better understanding of the influence and the impact of oppressive social environments and evolving power relations on the development of an organization.
URBAN EDUCATION SYSTEMS ANALYSIS.
CLARK, STEPHEN C.; AND OTHERS
ANALYSIS OF URBAN EDUCATIONAL SYSTEMS MAY BE ACHIEVED BY USE OF AN ANALYTICAL MODEL. THE MODEL MAY BE USED IN DECISION-MAKING REGARDING SCHOOL LOCATION, ENROLLMENT, FACILITIES, ORGANIZATION, PROGRAMS AND COSTS. KNOWN DATA SUCH AS MONIES AVAILABLE, STAFF ALLOCATION, AND CURRENT SCHOOL PLANT ARE INTRODUCED INTO THE MODEL. IN THE STRUCTURE OF THE…
Qianxiang, Zhou
2012-07-01
It is very important to clarify the geometric characteristic of human body segment and constitute analysis model for ergonomic design and the application of ergonomic virtual human. The typical anthropometric data of 1122 Chinese men aged 20-35 years were collected using three-dimensional laser scanner for human body. According to the correlation between different parameters, curve fitting were made between seven trunk parameters and ten body parameters with the SPSS 16.0 software. It can be concluded that hip circumference and shoulder breadth are the most important parameters in the models and the two parameters have high correlation with the others parameters of human body. By comparison with the conventional regressive curves, the present regression equation with the seven trunk parameters is more accurate to forecast the geometric dimensions of head, neck, height and the four limbs with high precision. Therefore, it is greatly valuable for ergonomic design and analysis of man-machine system.This result will be very useful to astronaut body model analysis and application.
Segmentation, statistical analysis, and modelling of the wall system in ceramic foams
Energy Technology Data Exchange (ETDEWEB)
Kampf, Jürgen, E-mail: juergen.kampf@uni-ulm.de [University of Ulm, Mathematics Department, 89069 Ulm (Germany); Schlachter, Anna-Lena [University of Kaiserslautern, Mathematics Department, 67653 Kaiserslautern (Germany); Redenbach, Claudia, E-mail: redenbach@mathematik.uni-kl.de [University of Kaiserslautern, Mathematics Department, 67653 Kaiserslautern (Germany); Liebscher, André, E-mail: liebscher@mathematik.uni-kl.de [University of Kaiserslautern, Mathematics Department, 67653 Kaiserslautern (Germany)
2015-01-15
Closed walls in otherwise open foam structures may have a great impact on macroscopic properties of the materials. In this paper, we present two algorithms for the segmentation of such closed walls from micro-computed tomography images of the foam structure. The techniques are compared on simulated data and applied to tomographic images of ceramic filters. This allows for a detailed statistical analysis of the normal directions and sizes of the walls. Finally, we explain how the information derived from the segmented wall system can be included in a stochastic microstructure model for the foam.
Mönch, Lars; Mason, Scott J
2012-01-01
Over the last fifty-plus years, the increased complexity and speed of integrated circuits have radically changed our world. Today, semiconductor manufacturing is perhaps the most important segment of the global manufacturing sector. As the semiconductor industry has become more competitive, improving planning and control has become a key factor for business success. This book is devoted to production planning and control problems in semiconductor wafer fabrication facilities. It is the first book that takes a comprehensive look at the role of modeling, analysis, and related information systems
Analysis, modeling and optimum design of solar domestic hot water systems
Energy Technology Data Exchange (ETDEWEB)
Lin Qin
1998-12-31
The object of this study was dynamic modeling, simulation and optimum design of solar DHW (domestic hot water) systems, with respect to different whether conditions, and accurate dynamic behaviour of the heat load. Special attention was paid to systems with thermosyphon and drain-back design. The solar radiation in Beijing (China) and in Denmark are analyzed both by theoretical calculations and the analysis of long-term measurements. Based on the weather data from the Beijing Meteorological Station during the period of 1981-1993, a Beijing Test Reference Year has been formulated by means of statistical analysis. A brief introduction about the Danish Test Reference Year and the Design Reference Year is also presented. In order to investigate the heat loss as a part of the total heat load, dynamic models for distribution networks have been developed, and simulations have been carried out for typically designed distribution networks of the circulation type. The influence of operation parameters such as the tank outlet temperature, the hot-water load and the load pattern, on the heat loss from the distribution networks in presented. It was found that the tank outlet temperature has a significant influence on the heat loss from a circulation type of distribution network, while the hot-water load and the load pattern have no obvious effect. Dynamic models of drain-back tanks, both as a separated tank and combined with a mantle tank, have been developed and presented. Models of the other basic components commonly used in solar DHW systems, such as flat-plate collectors, connection pipes, storage tanks with a heat exchanger spiral, and controllers, are also described. (LN) 66 refs.
Ceylan, Halil; Gopalakrishnan, Kasthurirangan; Birkan Bayrak, Mustafa; Guclu, Alper
2013-09-01
The need to rapidly and cost-effectively evaluate the present condition of pavement infrastructure is a critical issue concerning the deterioration of ageing transportation infrastructure all around the world. Nondestructive testing (NDT) and evaluation methods are well-suited for characterising materials and determining structural integrity of pavement systems. The falling weight deflectometer (FWD) is a NDT equipment used to assess the structural condition of highway and airfield pavement systems and to determine the moduli of pavement layers. This involves static or dynamic inverse analysis (referred to as backcalculation) of FWD deflection profiles in the pavement surface under a simulated truck load. The main objective of this study was to employ biologically inspired computational systems to develop robust pavement layer moduli backcalculation algorithms that can tolerate noise or inaccuracies in the FWD deflection data collected in the field. Artificial neural systems, also known as artificial neural networks (ANNs), are valuable computational intelligence tools that are increasingly being used to solve resource-intensive complex engineering problems. Unlike the linear elastic layered theory commonly used in pavement layer backcalculation, non-linear unbound aggregate base and subgrade soil response models were used in an axisymmetric finite element structural analysis programme to generate synthetic database for training and testing the ANN models. In order to develop more robust networks that can tolerate the noisy or inaccurate pavement deflection patterns in the NDT data, several network architectures were trained with varying levels of noise in them. The trained ANN models were capable of rapidly predicting the pavement layer moduli and critical pavement responses (tensile strains at the bottom of the asphalt concrete layer, compressive strains on top of the subgrade layer and the deviator stresses on top of the subgrade layer), and also pavement
LaRocca, Sarah; Johansson, Jonas; Hassel, Henrik; Guikema, Seth
2015-04-01
Critical infrastructure systems must be both robust and resilient in order to ensure the functioning of society. To improve the performance of such systems, we often use risk and vulnerability analysis to find and address system weaknesses. A critical component of such analyses is the ability to accurately determine the negative consequences of various types of failures in the system. Numerous mathematical and simulation models exist that can be used to this end. However, there are relatively few studies comparing the implications of using different modeling approaches in the context of comprehensive risk analysis of critical infrastructures. In this article, we suggest a classification of these models, which span from simple topologically-oriented models to advanced physical-flow-based models. Here, we focus on electric power systems and present a study aimed at understanding the tradeoffs between simplicity and fidelity in models used in the context of risk analysis. Specifically, the purpose of this article is to compare performance estimates achieved with a spectrum of approaches typically used for risk and vulnerability analysis of electric power systems and evaluate if more simplified topological measures can be combined using statistical methods to be used as a surrogate for physical flow models. The results of our work provide guidance as to appropriate models or combinations of models to use when analyzing large-scale critical infrastructure systems, where simulation times quickly become insurmountable when using more advanced models, severely limiting the extent of analyses that can be performed.
Parumasur, N.; Willie, R.
2008-09-01
We consider a simple HIV/AIDs finite dimensional mathematical model on interactions of the blood cells, the HIV/AIDs virus and the immune system for consistence of the equations to the real biomedical situation that they model. A better understanding to a cure solution to the illness modeled by the finite dimensional equations is given. This is accomplished through rigorous mathematical analysis and is reinforced by numerical analysis of models developed for real life cases.
National Aeronautics and Space Administration — As NASA modeling efforts grow more complex and more distributed among many working groups, new tools and technologies are required to integrate their efforts...
An Analysis on a Negotiation Model Based on Multiagent Systems with Symbiotic Learning and Evolution
Hossain, Md. Tofazzal
This study explores an evolutionary analysis on a negotiation model based on Masbiole (Multiagent Systems with Symbiotic Learning and Evolution) which has been proposed as a new methodology of Multiagent Systems (MAS) based on symbiosis in the ecosystem. In Masbiole, agents evolve in consideration of not only their own benefits and losses, but also the benefits and losses of opponent agents. To aid effective application of Masbiole, we develop a competitive negotiation model where rigorous and advanced intelligent decision-making mechanisms are required for agents to achieve solutions. A Negotiation Protocol is devised aiming at developing a set of rules for agents' behavior during evolution. Simulations use a newly developed evolutionary computing technique, called Genetic Network Programming (GNP) which has the directed graph-type gene structure that can develop and design the required intelligent mechanisms for agents. In a typical scenario, competitive negotiation solutions are reached by concessions that are usually predetermined in the conventional MAS. In this model, however, not only concession is determined automatically by symbiotic evolution (making the system intelligent, automated, and efficient) but the solution also achieves Pareto optimal automatically.
DEFF Research Database (Denmark)
Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede
2017-01-01
This paper presents a harmonic instability analysis method using state-space modeling and participation analysis in the inverter-fed ac power systems. A full-order state-space model for the droop-controlled Distributed Generation (DG) inverter is built first, including the time delay of the digit...
Advances in coupled safety modeling using systems analysis and high-fidelity methods.
Energy Technology Data Exchange (ETDEWEB)
Fanning, T. H.; Thomas, J. W.; Nuclear Engineering Division
2010-05-31
The potential for a sodium-cooled fast reactor to survive severe accident initiators with no damage has been demonstrated through whole-plant testing in EBR-II and FFTF. Analysis of the observed natural protective mechanisms suggests that they would be characteristic of a broad range of sodium-cooled fast reactors utilizing metal fuel. However, in order to demonstrate the degree to which new, advanced sodium-cooled fast reactor designs will possess these desired safety features, accurate, high-fidelity, whole-plant dynamics safety simulations will be required. One of the objectives of the advanced safety-modeling component of the Reactor IPSC is to develop a science-based advanced safety simulation capability by utilizing existing safety simulation tools coupled with emerging high-fidelity modeling capabilities in a multi-resolution approach. As part of this integration, an existing whole-plant systems analysis code has been coupled with a high-fidelity computational fluid dynamics code to assess the impact of high-fidelity simulations on safety-related performance. With the coupled capabilities, it is possible to identify critical safety-related phenomenon in advanced reactor designs that cannot be resolved with existing tools. In this report, the impact of coupling is demonstrated by evaluating the conditions of outlet plenum thermal stratification during a protected loss of flow transient. Outlet plenum stratification was anticipated to alter core temperatures and flows predicted during natural circulation conditions. This effect was observed during the simulations. What was not anticipated, however, is the far-reaching impact that resolving thermal stratification has on the whole plant. The high temperatures predicted at the IHX inlet due to thermal stratification in the outlet plenum forces heat into the intermediate system to the point that it eventually becomes a source of heat for the primary system. The results also suggest that flow stagnation in the
Directory of Open Access Journals (Sweden)
Baltzis KonstantinosB
2008-01-01
Full Text Available Abstract A common assumption in cellular communications is the circular-cell approximation. In this paper, an alternative analysis based on the hexagonal shape of the cells is presented. A geometrical-based stochastic model is proposed to describe the angle of arrival of the interfering signals in the reverse link of a cellular system. Explicit closed form expressions are derived, and simulations performed exhibit the characteristics and validate the accuracy of the proposed model. Applications in the capacity estimation of WCDMA cellular networks are presented. Dependence of system capacity of the sectorization of the cells and the base station antenna radiation pattern is explored. Comparisons with data in literature validate the accuracy of the proposed model. The degree of error of the hexagonal and the circular-cell approaches has been investigated indicating the validity of the proposed model. Results have also shown that, in many cases, the two approaches give similar results when the radius of the circle equals to the hexagon inradius. A brief discussion on how the proposed technique may be applied to broadband access networks is finally made.
The Calibration Model and Simulation Analysis of Circular Scanning Airborne Laser Bathymetry System
Directory of Open Access Journals (Sweden)
SHEN Erhua
2016-08-01
Full Text Available To improve the positioning accuracy of circular scanning airborne laser bathymetry system, a calibration method is presented in this paper. When the laser points are collected by the bathymetry system on the level area, they should be on the same plane. However, they are not coplanar because of systematic error and random error. So we try to fit the points to a plane, which may help to adjust the errors and then correct the point location.Firstly, the circular scanning airborne laser bathymetry positioning model is derived in the simple mode. The intersection of laser line and sea surface is simulated depending on the mathematical principles of line and plane intersection. Combined with the direction vector of laser line in the water got by the refraction principle, the sea floor plane mathematical equation is used to compute the location of the laser points. Then, the parameter weighted least squares adjustment model is derived with the prior variance introduced, which lays the foundation for the following computing of calibration model. Finally, the calibration adjustment mathematic model and the detailed computing process are derived. The simulation computing and analysis for the calibration process is presented, and some meaningful conclusions for the calibration are achieved.
Modeling and Analysis of the Ranchero Coaxial Explosive Pulse Power Generator System
Energy Technology Data Exchange (ETDEWEB)
Atchison, W.L.; Goforth, J.H.; Lindemuth, I.R.; Reinovsky, R.E.
1999-06-28
A key element in the design of a coaxial generator system is the simplicity of the geometry. The clean cylindrical geometry allows us a reasonable chance at modeling RANCHERO performance using our 1D and 2D MHD modeling codes. The results of numerical simulations have been compare to several tests of the RANCHERO system in a variety of configurations. Recent comparisons of 1D calculations with the REOT-2 data have been extremely good and suggest that the generator is behaving in a very 1D like nature until reaching 90-95% of peak current. Differences between calculated current and measured performance during the last 3 mm (out of 70 mm) of flux compression may be a consequence of either the EOS for SF{sub 6}, 2D effects, or both. This study will examine the existing models and attempt to provide a robust integrated model which can then be used to drive design studies, pre- and post-shot analysis, and predict performance parameters for slight variations of the base design of RANCHE RO.
Directory of Open Access Journals (Sweden)
Konstantinos B. Baltzis
2008-10-01
Full Text Available A common assumption in cellular communications is the circular-cell approximation. In this paper, an alternative analysis based on the hexagonal shape of the cells is presented. A geometrical-based stochastic model is proposed to describe the angle of arrival of the interfering signals in the reverse link of a cellular system. Explicit closed form expressions are derived, and simulations performed exhibit the characteristics and validate the accuracy of the proposed model. Applications in the capacity estimation of WCDMA cellular networks are presented. Dependence of system capacity of the sectorization of the cells and the base station antenna radiation pattern is explored. Comparisons with data in literature validate the accuracy of the proposed model. The degree of error of the hexagonal and the circular-cell approaches has been investigated indicating the validity of the proposed model. Results have also shown that, in many cases, the two approaches give similar results when the radius of the circle equals to the hexagon inradius. A brief discussion on how the proposed technique may be applied to broadband access networks is finally made.
Aires, Filipe; Rossow, William B.; Hansen, James E. (Technical Monitor)
2001-01-01
A new approach is presented for the analysis of feedback processes in a nonlinear dynamical system by observing its variations. The new methodology consists of statistical estimates of the sensitivities between all pairs of variables in the system based on a neural network modeling of the dynamical system. The model can then be used to estimate the instantaneous, multivariate and nonlinear sensitivities, which are shown to be essential for the analysis of the feedbacks processes involved in the dynamical system. The method is described and tested on synthetic data from the low-order Lorenz circulation model where the correct sensitivities can be evaluated analytically.
Razavi, S.; Gupta, H. V.
2015-12-01
Earth and environmental systems models (EESMs) are continually growing in complexity and dimensionality with continuous advances in understanding and computing power. Complexity and dimensionality are manifested by introducing many different factors in EESMs (i.e., model parameters, forcings, boundary conditions, etc.) to be identified. Sensitivity Analysis (SA) provides an essential means for characterizing the role and importance of such factors in producing the model responses. However, conventional approaches to SA suffer from (1) an ambiguous characterization of sensitivity, and (2) poor computational efficiency, particularly as the problem dimension grows. Here, we present a new and general sensitivity analysis framework (called VARS), based on an analogy to 'variogram analysis', that provides an intuitive and comprehensive characterization of sensitivity across the full spectrum of scales in the factor space. We prove, theoretically, that Morris (derivative-based) and Sobol (variance-based) methods and their extensions are limiting cases of VARS, and that their SA indices can be computed as by-products of the VARS framework. We also present a practical strategy for the application of VARS to real-world problems, called STAR-VARS, including a new sampling strategy, called "star-based sampling". Our results across several case studies show the STAR-VARS approach to provide reliable and stable assessments of "global" sensitivity across the full range of scales in the factor space, while being at least 1-2 orders of magnitude more efficient than the benchmark Morris and Sobol approaches.
Ibnkahla, Mohamed
2012-12-01
Neural network (NN) approaches have been widely applied for modeling and identification of nonlinear multiple-input multiple-output (MIMO) systems. This paper proposes a stochastic analysis of a class of these NN algorithms. The class of MIMO systems considered in this paper is composed of a set of single-input nonlinearities followed by a linear combiner. The NN model consists of a set of single-input memoryless NN blocks followed by a linear combiner. A gradient descent algorithm is used for the learning process. Here we give analytical expressions for the mean squared error (MSE), explore the stationary points of the algorithm, evaluate the misadjustment error due to weight fluctuations, and derive recursions for the mean weight transient behavior during the learning process. The paper shows that in the case of independent inputs, the adaptive linear combiner identifies the linear combining matrix of the MIMO system (to within a scaling diagonal matrix) and that each NN block identifies the corresponding unknown nonlinearity to within a scale factor. The paper also investigates the particular case of linear identification of the nonlinear MIMO system. It is shown in this case that, for independent inputs, the adaptive linear combiner identifies a scaled version of the unknown linear combining matrix. The paper is supported with computer simulations which confirm the theoretical results.
A model-based systems approach to pharmaceutical product-process design and analysis
DEFF Research Database (Denmark)
Gernaey, Krist; Gani, Rafiqul
2010-01-01
This is a perspective paper highlighting the need for systematic model-based design and analysis in pharmaceutical product-process development. A model-based framework is presented and the role, development and use of models of various types are discussed together with the structure of the models...... for the product and the process. The need for a systematic modelling framework is highlighted together with modelling issues related to model identification, adaptation and extension. In the area of product design and analysis, predictive models are needed with a wide application range. In the area of process...... synthesis and design, the use of generic process models from which specific process models can be generated, is highlighted. The use of a multi-scale modelling approach to extend the application range of the property models is highlighted as well. Examples of different types of process models, model...
Second Law Analysis of the Earth System with a Radiative Model
Directory of Open Access Journals (Sweden)
Sean Wright
2002-06-01
Full Text Available Solar radiation provides the energy for many processes on Earth including processes that sustain living systems and circulation of the atmosphere and oceans. The Earth does not consume this energy; it is simply converted to outgoing thermal radiation. However, the entropy production rate of Earth causes energy degradation and the exergy destruction rate quantifies this degradation relative to a reference environment. The global entropy production rate also provides an additional constraint for comparison with atmospheric modeling results. In this paper a simplified expression for the global entropy production rate, associated with the absorbed portion of the solar flux, is presented based on a radiative model. The second purpose of this work is to investigate the exergetic analysis of the Earth. It is desirable to consider environment temperatures that are typical temperatures on Earth when comparing the total entropy production rate and irreversibility rate of the planet to those due to processes such as the global energy system; in other words, typical temperatures where these processes occur. However, multiplying the estimated global entropy production rate by an arbitrary environment temperature appears to result in irreversibility rates that violate the second law of thermodynamics. It is shown that the radiative interaction of the Earth with its surroundings can be theoretically modeled and tested in a laboratory environment showing that arbitrary environment temperature specifications should not cause these violations. These apparent violations are resolved through corrections to the energy, entropy and exergy calculations that are due to the specific character of radiative heat transfer. As a result, this analysis also provides an illustrative example of the implications of environment specifications on exergy analysis involving radiative heat transfer.
Razavi, Saman; Gupta, Hoshin
2015-04-01
Earth and Environmental Systems (EES) models are essential components of research, development, and decision-making in science and engineering disciplines. With continuous advances in understanding and computing power, such models are becoming more complex with increasingly more factors to be specified (model parameters, forcings, boundary conditions, etc.). To facilitate better understanding of the role and importance of different factors in producing the model responses, the procedure known as 'Sensitivity Analysis' (SA) can be very helpful. Despite the availability of a large body of literature on the development and application of various SA approaches, two issues continue to pose major challenges: (1) Ambiguous Definition of Sensitivity - Different SA methods are based in different philosophies and theoretical definitions of sensitivity, and can result in different, even conflicting, assessments of the underlying sensitivities for a given problem, (2) Computational Cost - The cost of carrying out SA can be large, even excessive, for high-dimensional problems and/or computationally intensive models. In this presentation, we propose a new approach to sensitivity analysis that addresses the dual aspects of 'effectiveness' and 'efficiency'. By effective, we mean achieving an assessment that is both meaningful and clearly reflective of the objective of the analysis (the first challenge above), while by efficiency we mean achieving statistically robust results with minimal computational cost (the second challenge above). Based on this approach, we develop a 'global' sensitivity analysis framework that efficiently generates a newly-defined set of sensitivity indices that characterize a range of important properties of metric 'response surfaces' encountered when performing SA on EES models. Further, we show how this framework embraces, and is consistent with, a spectrum of different concepts regarding 'sensitivity', and that commonly-used SA approaches (e.g., Sobol
Soft particle analysis of electrokinetics of biological cells and their model systems
Directory of Open Access Journals (Sweden)
Kimiko Makino and Hiroyuki Ohshima
2011-01-01
Full Text Available In this article, we review the applications of a novel theory (Ohshima 2009 Sci. Technol. Adv. Mater. 10 063001 to the analysis of electrokinetic data for various soft particles, that is, particles covered with an ion-permeable surface layer of polyelectrolytes. Soft particles discussed in this review include various biological cells and hydrogel-coated particles as a model of biological cells. Cellular transformations increase the concentration of sialic acid of glycoproteins and are associated with blocked biosynthesis of glycolipids and aberrant expression of the developmentally programmed biosynthetic pathway. The change in shape or biological function of cells may affect their surface properties and can be detected by electrokinetic measurements. The experimental results were analyzed with Ohshima's electrokinetic formula for soft particles and soft surfaces. As a model system, hydrogel surfaces that mimic biological surfaces were also prepared and their surface properties were studied.
Feingold, Harvey; ONeil, Dan (Technical Monitor)
2002-01-01
In response to a recommendation from OMB, NASA's Fiscal Year 2001 budget included a new program within the HEDS (Human Exploration and Development of Space) Enterprise called HEDS Technology/ Commercialization Initiative (HTCI). HTCI had three overarching goals: to support REDS analysis and planning for safe, affordable and effective future programs and projects that advance human exploration, scientific discovery, and the commercial development of space; to pursue research, development, and validation of breakthrough technologies and highly innovative systems concepts; and to advance die creation of strong partnerships within NASA, with U.S. industry and universities, and internationally. As part of its contracted effort, SAIC was to write a report contribution, describing die results of its task activities, to a final HTCI report prepared by MSFC. Unfortunately, government cancellation of the HTCI program in the summer of 2001 curtailed all efforts on the program including die Final HTCI report. In the absence of that report, SAIC has issued this final report in an attempt to document some of the technical material it produced. The report contains SAIC presentations for both HTCI workshops; a set of roadmap charts for the Systems Analysis, Integration and Modeling; and charts showing the evolution of the current TITAN modeling architecture.
Feingold, Harvey; ONeil, Dan (Technical Monitor)
2002-01-01
In response to a recommendation from OMB, NASA's Fiscal Year 2001 budget included a new program within the HEDS (Human Exploration and Development of Space) Enterprise called HEDS Technology/ Commercialization Initiative (HTCI). HTCI had three overarching goals: to support REDS analysis and planning for safe, affordable and effective future programs and projects that advance human exploration, scientific discovery, and the commercial development of space; to pursue research, development, and validation of breakthrough technologies and highly innovative systems concepts; and to advance die creation of strong partnerships within NASA, with U.S. industry and universities, and internationally. As part of its contracted effort, SAIC was to write a report contribution, describing die results of its task activities, to a final HTCI report prepared by MSFC. Unfortunately, government cancellation of the HTCI program in the summer of 2001 curtailed all efforts on the program including die Final HTCI report. In the absence of that report, SAIC has issued this final report in an attempt to document some of the technical material it produced. The report contains SAIC presentations for both HTCI workshops; a set of roadmap charts for the Systems Analysis, Integration and Modeling; and charts showing the evolution of the current TITAN modeling architecture.
A glacial systems model configured for large ensemble analysis of Antarctic deglaciation
Directory of Open Access Journals (Sweden)
R. Briggs
2013-04-01
Full Text Available This article describes the Memorial University of Newfoundland/Penn State University (MUN/PSU glacial systems model (GSM that has been developed specifically for large-ensemble data-constrained analysis of past Antarctic Ice Sheet evolution. Our approach emphasizes the introduction of a large set of model parameters to explicitly account for the uncertainties inherent in the modelling of such a complex system. At the core of the GSM is a 3-D thermo-mechanically coupled ice sheet model that solves both the shallow ice and shallow shelf approximations. This enables the different stress regimes of ice sheet, ice shelves, and ice streams to be represented. The grounding line is modelled through an analytical sub-grid flux parametrization. To this dynamical core the following have been added: a heavily parametrized basal drag component; a visco-elastic isostatic adjustment solver; a diverse set of climate forcings (to remove any reliance on any single method; tidewater and ice shelf calving functionality; and a new physically-motivated empirically-derived sub-shelf melt (SSM component. To assess the accuracy of the latter, we compare predicted SSM values against a compilation of published observations. Within parametric and observational uncertainties, computed SSM for the present day ice sheet is in accord with observations for all but the Filchner ice shelf. The GSM has 31 ensemble parameters that are varied to account (in part for the uncertainty in the ice-physics, the climate forcing, and the ice-ocean interaction. We document the parameters and parametric sensitivity of the model to motivate the choice of ensemble parameters in a quest to approximately bound reality (within the limits of 31 parameters.
Séror, Ann
2003-01-01
The objective of this paper is to present a strategy for the qualitative analysis of virtual institutional infrastructures serving complex healthcare systems. Methodologies considered include case analysis, grounded theory, and sociometry. The discussion is illustrated with references to case analyses of diverse healthcare systems. Particular attention is focused on ideological values expressed in market dynamics and system control structures.
Séror, Ann
2003-01-01
The objective of this paper is to present a strategy for the qualitative analysis of virtual institutional infrastructures serving complex healthcare systems. Methodologies considered include case analysis, grounded theory, and sociometry. The discussion is illustrated with references to case analyses of diverse healthcare systems. Particular attention is focused on ideological values expressed in market dynamics and system control structures.
An approach for model-based energy cost analysis of industrial automation systems
Energy Technology Data Exchange (ETDEWEB)
Beck, A.; Goehner, P. [Institute of Industrial Automation and Software Engineering, University of Stuttgart, Pfaffenwaldring 47, 70550 Stuttgart (Germany)
2012-08-15
Current energy reports confirm the steadily dilating gap between available conventional energy resources and future energy demand. This gap results in increasing energy costs and has become a determining factor in economies. Hence, politics, industry, and research focus either on regenerative energy resources or on energy-efficient concepts, methods, and technologies for energy-consuming devices. A remaining challenge is energy optimization of complex systems during their operation time. In addition to optimization measures that can be applied in development and engineering, the generation of optimization measures that are customized to the specific dynamic operational situation, promise high-cost saving potentials. During operation time, the systems are located in unique situations and environments and are operated according to individual requirements of their users. Hence, in addition to complexity of the systems, individuality and dynamic variability of their surroundings during operation time complicate identification of goal-oriented optimization measures. This contribution introduces a model-based approach for user-centric energy cost analysis of industrial automation systems. The approach allows automated generation and appliance of individual optimization proposals. Focus of this paper is on a basic variant for a single industrial automation system and its operational parameters.
MATHEMATICAL MODEL OF THE DAMAGE ANALYSIS OF RAILWAY TRACTION ENERGY SYSTEM
Directory of Open Access Journals (Sweden)
O. O. Matusevych
2015-05-01
Full Text Available Purpose. The study provides the methods and models development of reducing damages of traction energy systems (TES at electrified railways of Ukraine. Definition the indicator of preventing damage evaluation TES at electrified railways is necessary. Paper is aimed to search the modern methods and approaches to improve the system of TES monitoring, diagnosis and maintenance. Methodology. To achieve this purpose a study of foreign experience and publications that focus on problem-solving quality of TES using a linguistic approach based on the theory of fuzzy multiple numbers and linguistic variable were done. Findings. In result of research an algorithm to reduce TPS damages which operates under uncertainty was developed. It is found that the solution of this problem is possible by timely detection of actual technical condition of equipment in terms of quality maintenance, diagnostics and update resource of electrical equipment traction substations (TS power supply TES. The study examined the fuzzy inference scheme, which is based on the use of mechanisms to minimize the area of decision-making. It contributes not only to structural identification in the process of developing a database, but also can significantly improve the efficiency of finding the parameters of fuzzy model, which in turn reduces the efforts that are necessary for the analysis and the design of effective control systems maintenance and repair (M and R TES. Originality. For the first time the algorithm of reduction the damage of traction energy system of electrified railways of Ukraine was offered. The mathematical model of reduction the damage calculation of TES from TP power equipment failures by improving system maintenance (M and P was developed. Firstly evaluation index was proposed to prevent the damage of traction energy system. Practical value. The article describes the fuzzy inference scheme, which is based on the use of the mechanism to minimize the area of decision
High Frequency Model of Electrified Railway Propulsion System for EMC Analysis
Jia, Kelin
2012-01-01
A model of the electrified railway propulsion system working in a wide frequency range is studied in this thesis. The high frequency modeling is the first stage to study and predict the Electromagnetic compatibility (EMC) problems in the electrified railway propulsion system, which are safety and reliability issues of high concern. Modeling methods and models for the line converter, motor power supply module, and the traction motor are developed. These models can work individually or be combi...
Lane, Rebecca E.; Korbie, Darren; Anderson, Will; Vaidyanathan, Ramanathan; Trau, Matt
2015-01-01
Exosomes are vesicles which have garnered interest due to their diagnostic and therapeutic potential. Isolation of pure yields of exosomes from complex biological fluids whilst preserving their physical characteristics is critical for downstream applications. In this study, we use 100 nm-liposomes from 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol as a model system as a model system to assess the effect of exosome isolation protocols on vesicle recovery and size distribution using a single-particle analysis method. We demonstrate that liposome size distribution and ζ-potential are comparable to extracted exosomes, making them an ideal model for comparison studies. Four different purification protocols were evaluated, with liposomes robustly isolated by three of them. Recovered yields varied and liposome size distribution was unaltered during processing, suggesting that these protocols do not induce particle aggregation. This leads us to conclude that the size distribution profile and characteristics of vesicles are stably maintained during processing and purification, suggesting that reports detailing how exosomes derived from tumour cells differ in size to those from normal cells are reporting a real phenomenon. However, we hypothesize that larger particles present in most purified exosome samples represent co-purified contaminating non-exosome debris. These isolation techniques are therefore likely nonspecific and may co-isolate non-exosome material of similar physical properties.
Institute of Scientific and Technical Information of China (English)
胡继敏; 金家善; 严志腾
2013-01-01
The thermodynamic charge performance of a variable-mass thermodynamic system was investigated by the simulation modeling and experimental analysis. Three sets of experiments were conducted for various charge time and charge steam flow under three different control strategies of charge valve. Characteristic performance parameters from the average sub-cooled degree and the charging energy coefficient point of views were also defined to evaluate and predict the charge performance of system combined with the simulation model and experimental data. The results show that the average steam flow reflects the average sub-cooled degree qualitatively, while the charging energy coefficients of 74.6%, 69.9% and 100% relate to the end value of the average sub-cooled degree at 2.1, 2.9 and 0 respectively for the three sets of experiments. The mean and maximum deviations of the results predicted from those by experimental data are smaller than 6.8% and 10.8%, respectively. In conclusion, the decrease of average steam flow can effectively increase the charging energy coefficient in the same charge time condition and therefore improve the thermodynamic charge performance of system. While the increase of the charging energy coefficient by extending the charge time needs the consideration of the operating frequency for steam users.
Machiels, M.A.M.; Udo, H.M.J.; Densen, van W.L.T.
1994-01-01
Modelling of animal production systems as a whole is mainly used for extensively managed systems, such as fishing and hunting natural animal populations. This type of modelling is widely used in fisheries management, but has as yet found limited application in the modelling of extensive cultivation
Development of CCF modeling and analysis methodology for diverse system status
Energy Technology Data Exchange (ETDEWEB)
Lim, Tae Jin; Byun, Si Sub; Yoon, Tae Kwan [Soongsil University, Seoul (Korea); Moon, Jae Pil [Seoul National University, Seoul (Korea)
1999-04-01
The objectives of this project is to develop a procedure for modeling and analyzing CCF efficiently according to various system status. CCF events change according to the change of the system status due to maintenance, accidents, or alternating success criteria for various missions. The objective of the first year's research is to develope a CCF model for various system status. We reviewed and evaluated current CCF models, and analyze their merits and deficiency in modeling various system status. An approximate model is developed as a CCF model. The model is compatible with MGL model. Extensive sensitivity study shows the accuracy and efficiency of the proposed model. Second year's research aims to the development of an integrated CCF procedure for PSA and risk monitor. We develope an adaptive method for the approximate model in a k/m/G system with multiple common cause groups. The accuracy of the method is proved by comparing with the implicit method. Next, we develope a method for modeling CCF in a fault tree. Three alternatives are considered. It is proved to be most efficient to model the CCF events under the gate of individual component failure. The we provides a method for estimating the CCF probability, and develope a software for this purpose. We finally provide a fundamental procedure for modeling CCF in a risk monitor. The modeling procedure is applied to HPSI system, and it is proved to be efficient and accurate. (author). 48 refs., 11 figs., 53 tabs.
Energy Technology Data Exchange (ETDEWEB)
York, A.A.; Chipchak, J.S.
1979-03-01
Models for Optimum Repair-Level Analysis (ORLA) and Life Cycle Cost (LCC) analysis for Base and Installation Security System (BISS) equipment are described. The ORLA model determines the costs of alternative maintenance approaches for selection of the most economic maintenance approach. The LCC model determines the total cost to the Government for the development, acquisition, initial logistics support, and recurring support of a system over the projected inventory usage period. A unique feature of these models is the marriage of ORLA and ICC which enables LCC to utilize completely the most economic ORLA decision costs. This significantly reduces the overall LCC effort.
Novikov, Dmitry; Bakhtadze, Natalia; Zaikin, Oleg
2016-01-01
This book demonstrates how to apply modern approaches to complex system control in practical applications involving knowledge-based systems. The dimensions of knowledge-based systems are extended by incorporating new perspectives from control theory, multimodal systems and simulation methods. The book is divided into three parts: theory, production system and information system applications. One of its main focuses is on an agent-based approach to complex system analysis. Moreover, specialised forms of knowledge-based systems (like e-learning, social network, and production systems) are introduced with a new formal approach to knowledge system modelling. The book, which offers a valuable resource for researchers engaged in complex system analysis, is the result of a unique cooperation between scientists from applied computer science (mainly from Poland) and leading system control theory researchers from the Russian Academy of Sciences’ Trapeznikov Institute of Control Sciences.
Toward a mathematical model of solar radiation for engineering analysis of solar energy systems
Hamilton, C. L.; Reid, M. S.
1976-01-01
The currently most-used insolation model and what improvements might be made in it to better suit it for use in designing energy systems is discussed. An approach to constructing an upgraded model is sketched.
Evapotranspiration Model Analysis of Crop Water Use in Plant Factory System
National Research Council Canada - National Science Library
PAMUNGKAS, Agung Putra; HATOU, Kenji; MORIMOTO, Tetsuo
2014-01-01
...) rates that occur inside a plant factory system was made using the Stanghellini model. The Stanghellini model is considered more appropriate for estimating the rate of ET inside the soilless culture of greenhouse tomatoes...
Wagener, T.; Pianosi, F.; Almeida, S.; Holcombe, E.
2016-12-01
We can define epistemic uncertainty as those uncertainties that are not well determined by historical observations. This lack of determination can be because the future is not like the past, because the historical data is unreliable (imperfectly recorded from proxies or missing), or because it is scarce (either because measurements are not available at the right scale or there is simply no observation or network available). This kind of uncertainty is typical for earth system modelling, but our approaches to address it are poorly developed. Because epistemic uncertainties cannot easily be characterised by probability distributions, traditional uncertainty analysis techniques based on Monte Carlo simulation and forward propagation of uncertainty are not adequate. Global Sensitivity Analysis (GSA) can provide an alternative approach where, rather than quantifying the impact of poorly defined or even unknown uncertainties on model predictions, one can investigate at what level such uncertainties would start to matter and whether this level is likely to be reached within the relevant time period analysed. The underlying objective of GSA in this case lies in mapping the uncertain input factors onto critical regions of the model output, e.g. when the output exceeds a certain thresholds. Methods to implement this mapping step have so far received less attention and significant improvement is needed. We will present an example from landslide modelling - a field where observations are scarce, sub-surface characteristics are poorly constrained, and potential future rainfall triggers can be highly uncertain due to climate change. We demonstrate an approach that combines GSA and advanced Classification and Regression Tress (CART) to understand the risk of slope failure for an application in the Caribbean. We close with a discussion of opportunities for further methodological advancement.
Lam, Hak-Keung
2016-01-01
This book presents recent research on the stability analysis of polynomial-fuzzy-model-based control systems where the concept of partially/imperfectly matched premises and membership-function dependent analysis are considered. The membership-function-dependent analysis offers a new research direction for fuzzy-model-based control systems by taking into account the characteristic and information of the membership functions in the stability analysis. The book presents on a research level the most recent and advanced research results, promotes the research of polynomial-fuzzy-model-based control systems, and provides theoretical support and point a research direction to postgraduate students and fellow researchers. Each chapter provides numerical examples to verify the analysis results, demonstrate the effectiveness of the proposed polynomial fuzzy control schemes, and explain the design procedure. The book is comprehensively written enclosing detailed derivation steps and mathematical derivations also for read...
A Conceptual Aerospace Vehicle Structural System Modeling, Analysis and Design Process
Mukhopadhyay, Vivek
2007-01-01
A process for aerospace structural concept analysis and design is presented, with examples of a blended-wing-body fuselage, a multi-bubble fuselage concept, a notional crew exploration vehicle, and a high altitude long endurance aircraft. Aerospace vehicle structures must withstand all anticipated mission loads, yet must be designed to have optimal structural weight with the required safety margins. For a viable systems study of advanced concepts, these conflicting requirements must be imposed and analyzed early in the conceptual design cycle, preferably with a high degree of fidelity. In this design process, integrated multidisciplinary analysis tools are used in a collaborative engineering environment. First, parametric solid and surface models including the internal structural layout are developed for detailed finite element analyses. Multiple design scenarios are generated for analyzing several structural configurations and material alternatives. The structural stress, deflection, strain, and margins of safety distributions are visualized and the design is improved. Over several design cycles, the refined vehicle parts and assembly models are generated. The accumulated design data is used for the structural mass comparison and concept ranking. The present application focus on the blended-wing-body vehicle structure and advanced composite material are also discussed.
Mixed-Effects State Space Models for Analysis of Longitudinal Dynamic Systems
Liu, Dacheng; Lu, Tao; Niu, Xu-Feng; Wu, Hulin
2010-01-01
The rapid development of new biotechnologies allows us to deeply understand biomedical dynamic systems in more detail and at a cellular level. Many of the subject-specific biomedical systems can be described by a set of differential or difference equations which are similar to engineering dynamic systems. In this paper, motivated by HIV dynamic studies, we propose a class of mixed-effects state space models based on the longitudinal feature of dynamic systems. State space models with mixed-ef...
Nespoli, Adelaide; Rigamonti, Daniela; Riva, Marco; Villa, Elena; Passaretti, Francesca
2016-10-01
This work presents an experimental and numerical analysis of several parallel systems of NiTi pseudoelastic wires. Standard tensile tests were accomplished to evaluate the global damping capacity, the energy dissipated per cycle and the maximum attenuated force in a static condition. Besides, a numerical model was implemented to predict the damping response of more complex pseudoelastic arrangements. It was found a damping capacity upper limit of 0.09 regardless the number and the length of the NiTi components. In addition, it was found that the energy dissipated per cycle is related to the strain and to the number of the NiTi components; furthermore, the system composed of NiTi wires with different length allows for an elastic region that is related to the numbers of wires and that presents a modulation of the stiffness. Finally, the proposed numerical model allows a precise design of complex pseudoelastic combinations as it is able to represent the rhombohedral characteristic.
Case, Jonathan; Blottman, Pete; Hoeth, Brian; Oram, Timothy
2006-01-01
The Weather Research and Forecasting (WRF) model is the next generation community mesoscale model designed to enhance collaboration between the research and operational sectors. The NM'S as a whole has begun a transition toward WRF as the mesoscale model of choice to use as a tool in making local forecasts. Currently, both the National Weather Service in Melbourne, FL (NWS MLB) and the Spaceflight Meteorology Group (SMG) are running the Advanced Regional Prediction System (AIRPS) Data Analysis System (ADAS) every 15 minutes over the Florida peninsula to produce high-resolution diagnostics supporting their daily operations. In addition, the NWS MLB and SMG have used ADAS to provide initial conditions for short-range forecasts from the ARPS numerical weather prediction (NWP) model. Both NM'S MLB and SMG have derived great benefit from the maturity of ADAS, and would like to use ADAS for providing initial conditions to WRF. In order to assist in this WRF transition effort, the Applied Meteorology Unit (AMU) was tasked to configure and implement an operational version of WRF that uses output from ADAS for the model initial conditions. Both agencies asked the AMU to develop a framework that allows the ADAS initial conditions to be incorporated into the WRF Environmental Modeling System (EMS) software. Developed by the NM'S Science Operations Officer (S00) Science and Training Resource Center (STRC), the EMS is a complete, full physics, NWP package that incorporates dynamical cores from both the National Center for Atmospheric Research's Advanced Research WRF (ARW) and the National Centers for Environmental Prediction's Non-Hydrostatic Mesoscale Model (NMM) into a single end-to-end forecasting system. The EMS performs nearly all pre- and postprocessing and can be run automatically to obtain external grid data for WRF boundary conditions, run the model, and convert the data into a format that can be readily viewed within the Advanced Weather Interactive Processing System
Institute of Scientific and Technical Information of China (English)
WU Hao; CHEN Xiaoling; HE Ying; HE Xiaorong; CAI Xiaobin; XU Keyan
2006-01-01
Indicator systems of environmental sustainable development in the Poyang Lake Basin are established from 51 elementary indexes by factor analysis, which is composed of four steps such as the factor model, the parameter estimation, the factor rotation and the factor score. Under the condition that the cumulative proportion is greater than 85%, 5 explicit factors of environmental sustainable development as well as its factor score by region are carried out. The result indicates some impact factors to the basin environmental in descending sort order are volume of water, volume of waste gas discharge, volume of solid wastes, the degree to comprehensive utilization of waste gas, waste water and solid wastes, the emission volume of waste gas, waste water and solid wastes. It is helpful and important to provide decision support for constituting sustainable development strategies and evaluate the sustainable development status of each city.
Radhakrishnan, A.; Balaji, V.; Schweitzer, R.; Nikonov, S.; O'Brien, K.; Vahlenkamp, H.; Burger, E. F.
2016-12-01
There are distinct phases in the development cycle of an Earth system model. During the model development phase, scientists make changes to code and parameters and require rapid access to results for evaluation. During the production phase, scientists may make an ensemble of runs with different settings, and produce large quantities of output, that must be further analyzed and quality controlled for scientific papers and submission to international projects such as the Climate Model Intercomparison Project (CMIP). During this phase, provenance is a key concern:being able to track back from outputs to inputs. We will discuss one of the paths taken at GFDL in delivering tools across this lifecycle, offering on-demand analysis of data by integrating the use of GFDL's in-house FRE-Curator, Unidata's THREDDS and NOAA PMEL's Live Access Servers (LAS).Experience over this lifecycle suggests that a major difficulty in developing analysis capabilities is only partially the scientific content, but often devoted to answering the questions "where is the data?" and "how do I get to it?". "FRE-Curator" is the name of a database-centric paradigm used at NOAA GFDL to ingest information about the model runs into an RDBMS (Curator database). The components of FRE-Curator are integrated into Flexible Runtime Environment workflow and can be invoked during climate model simulation. The front end to FRE-Curator, known as the Model Development Database Interface (MDBI) provides an in-house web-based access to GFDL experiments: metadata, analysis output and more. In order to provide on-demand visualization, MDBI uses Live Access Servers which is a highly configurable web server designed to provide flexible access to geo-referenced scientific data, that makes use of OPeNDAP. Model output saved in GFDL's tape archive, the size of the database and experiments, continuous model development initiatives with more dynamic configurations add complexity and challenges in providing an on
A linear systems analysis of the yaw dynamics of a dynamically scaled insect model.
Dickson, William B; Polidoro, Peter; Tanner, Melissa M; Dickinson, Michael H
2010-09-01
Recent studies suggest that fruit flies use subtle changes to their wing motion to actively generate forces during aerial maneuvers. In addition, it has been estimated that the passive rotational damping caused by the flapping wings of an insect is around two orders of magnitude greater than that for the body alone. At present, however, the relationships between the active regulation of wing kinematics, passive damping produced by the flapping wings and the overall trajectory of the animal are still poorly understood. In this study, we use a dynamically scaled robotic model equipped with a torque feedback mechanism to study the dynamics of yaw turns in the fruit fly Drosophila melanogaster. Four plausible mechanisms for the active generation of yaw torque are examined. The mechanisms deform the wing kinematics of hovering in order to introduce asymmetry that results in the active production of yaw torque by the flapping wings. The results demonstrate that the stroke-averaged yaw torque is well approximated by a model that is linear with respect to both the yaw velocity and the magnitude of the kinematic deformations. Dynamic measurements, in which the yaw torque produced by the flapping wings was used in real-time to determine the rotation of the robot, suggest that a first-order linear model with stroke-average coefficients accurately captures the yaw dynamics of the system. Finally, an analysis of the stroke-average dynamics suggests that both damping and inertia will be important factors during rapid body saccades of a fruit fly.
Modelling and Analysis of Real Time Systems with Logic Programming and Constraints
DEFF Research Database (Denmark)
Banda, Gourinath
minimal model forms the basis for verifying the LHA model. We consider two techniques to verify the reactive properties specified as CTL formulas: (i) reachability analysis and (ii) model checking. A systematic translation of LHA models into constraint logic programs is de- fined. This is mechanised...... by a compiler. To facilitate forward and backward reasoning, two different ways to model an LHA are defined. A framework consist- ing of general purpose constraint logic program tools is presented to accomplish the reachability analysis to verify a class of safety and liveness properties. A tool to compute...
An Analysis/Synthesis System of Audio Signal with Utilization of an SN Model
Directory of Open Access Journals (Sweden)
G. Rozinaj
2004-12-01
Full Text Available An SN (sinusoids plus noise model is a spectral model, in which theperiodic components of the sound are represented by sinusoids withtime-varying frequencies, amplitudes and phases. The remainingnon-periodic components are represented by a filtered noise. Thesinusoidal model utilizes physical properties of musical instrumentsand the noise model utilizes the human inability to perceive the exactspectral shape or the phase of stochastic signals. SN modeling can beapplied in a compression, transformation, separation of sounds, etc.The designed system is based on methods used in the SN modeling. Wehave proposed a model that achieves good results in audio perception.Although many systems do not save phases of the sinusoids, they areimportant for better modelling of transients, for the computation ofresidual and last but not least for stereo signals, too. One of thefundamental properties of the proposed system is the ability of thesignal reconstruction not only from the amplitude but from the phasepoint of view, as well.
End-to-End Models for Effects of System Noise on LIMS Analysis of Igneous Rocks
Energy Technology Data Exchange (ETDEWEB)
Clegg, Samuel M [Los Alamos National Laboratory; Bender, Steven [Los Alamos National Laboratory; Wiens, R. C. [Los Alamos National Laboratory; Carmosino, Marco L [MT. HOLYOKE COLLEGE; Speicher, Elly A [MT. HOLYOKE COLLEGE; Dyar, M. D. [MT. HOLYOKE COLLEGE
2010-12-23
The ChemCam instrument on the Mars Science Laboratory will be the first extraterrestial deployment of laser-induced breakdown spectroscopy (UBS) for remote geochemical analysis. LIBS instruments are also being proposed for future NASA missions. In quantitative LIBS applications using multivariate analysis techniques, it is essential to understand the effects of key instrument parameters and their variability on the elemental predictions. Baseline experiments were run on a laboratory instrument in conditions reproducing ChemCam performance on Mars. These experiments employed Nd:YAG laser producing 17 mJ/pulse on target and an with a 200 {micro}m FWHM spot size on the surface of a sample. The emission is collected by a telescope, imaged on a fiber optic and then interfaced to a demultiplexer capable of >40% transmission into each spectrometer. We report here on an integrated end-to-end system performance model that simulates the effects of output signal degradation that might result from the input signal chain and the impact on multivariate model predictions. There are two approaches to modifying signal to noise (SNR): degrade the signal and/or increase the noise. Ishibashi used a much smaller data set to show that the addition of noise had significant impact while degradation of spectral resolution had much less impact on accuracy and precision. Here, we specifically focus on aspects of remote LIBS instrument performance as they relate to various types of signal degradation. To assess the sensitivity of LIBS analysis to signal-to-noise ratio (SNR) and spectral resolution, the signal in each spectrum from a suite of 50 laboratory spectra of igneous rocks was variably degraded by increasing the peak widths (simulating misalignment) and decreasing the spectral amplitude (simulating decreases in SNR).
Environmental system analysis of waste management. Experiences from applications of the ORWARE model
Energy Technology Data Exchange (ETDEWEB)
Bjoerklund, Anna
2000-11-01
Waste management has gone through a history of shifting problems, demands, and strategies over the years. In contrast to the long prevailing view that the problem could be solved by hiding or moving it, waste is now viewed as a problem ranging from local to global concern, and as being an integral part of several sectors in society. Decisive for this view has been society's increasing complexity and thus the increasing complexity of waste, together with a general development of environmental consciousness, moving from local focus on point emission sources, to regional and global issues of more complex nature. This thesis is about the development and application ORWARE; a model for computer aided environmental systems analysis of municipal waste management. Its origin is the hypothesis that widened perspectives are needed in waste management decision-making to avoid severe sub-optimisation of environmental performance. With a strong foundation in life cycle assessment (LCA), ORWARE aims to cover the environmental impacts over the entire life cycle of waste management. It also performs substance flow analysis (SFA) calculations at a rather detailed level of the system. Applying ORWARE has confirmed the importance of applying systems perspective and of taking into account site specific differences in analysis and planning of waste management, rather than relying on overly simplified solutions. Some findings can be generalised and used as guidelines to reduce environmental impact of waste management. Recovery of material and energy resources from waste generally leads to net reductions in energy use and environmental impact, because of the savings this brings about in other sectors. Waste treatment with low rate of energy and materials recovery should therefore be avoided. The exact choice of technology however depends on what products can be recovered and how they are used. Despite the complexity of the model and a certain degree of user unfriendliness, involved
Analysis of base isolation and energy dissipation systems for NPP structures using fragility models
Energy Technology Data Exchange (ETDEWEB)
Vulpe, A. [Technical Univ. of Iasi (Romania). Dept. of Structural Mechanics; Carausu, A. [Technical Univ. of Iasi (Romania). Dept. od Mathematics
1995-12-31
Some extensions of analytical models for base isolation and energy dissipation systems, involving fragility models, are presented. The equation of motion is extended with a term corresponding to Energy Dissipation effect, and the fragility of IEDS (Isolation and Energy Dissipations Systems) is evaluated using a bilinear regression line. (author). 11 refs., 2 figs.
Reliability-economics analysis models for photovoltaic power systems. Volume 1
Energy Technology Data Exchange (ETDEWEB)
Stember, L.H.; Huss, W.R.; Bridgman, M.S.
1982-11-01
This report describes the development of modeling techniques to characterize the reliability, availability, and maintenance costs of photovoltaic power systems. The developed models can be used by designers of PV systems in making design decisions and trade-offs to minimize life-cycle energy costs.
Students’ Decisions to Use an eLearning System: A Structural Equation Modelling Analysis
Directory of Open Access Journals (Sweden)
Muneer Abbad
2009-12-01
Full Text Available This research investigates and identifies some of the major factors affecting students’ adoption of an e-learning system at Arab Open University in Jordan. E-learning adoption is approached from the information systems acceptance point of view. An extended version of the Technology Acceptance Model (TAM was developed to investigate the underlying factors that influence students’ decisions to use an e-learning system. The proposed model uses the actual use of an e-learning system. It is different from most of the prior TAM studies, which only used a single dependent variable (intention to use. The model was estimated using Structural Equation Modelling (SEM. The final models derived from this study indicated that beliefs of usefulness and ease of use partially mediate the relationship between external factors and intention to use and actual use of e-learning systems.
Aithal, Sreeramana
2016-01-01
Studying the implications of a business model, choosing success strategies, developing viable operational concepts or evolving a functional system, it is important to analyse it in all dimensions. For this purpose, various analysing techniques/frameworks are used. This paper is a discussion on how to use an innovative analysing framework called ABCD model on a given business model, or on a business strategy or a operational concept/idea or business system. Based on four constructs Advantages,...
Modeling and Analysis of Hybrid Dynamic Systems Using Hybrid Petri Nets
GHOMRI Latefa; Alla, Hassane
2008-01-01
Some extensions of PNs permitting HDS modeling were presented here. The first models to be presented are continuous PNs. This model may be used for modeling either a continuous system or a discrete system. In this case, it is an approximation that is often satisfactory. Hybrid PNs combine in the same formalism a discrete PN and a continuous PN. Two hybrid PN models were considered in this chapter. The first, called the hybrid PN, has a deterministic behavior; this means that we can predict th...
Energy Technology Data Exchange (ETDEWEB)
Goering, Markus Heinrich
2013-10-25
comprehensive requirements for the superposition of event sequences and failure combinations. For this reason, the synthesis of a description language, under consideration of the aforementioned challenges, is necessary; supplemented by a method utilising the description language for efficient engineering and I and C design analysis. Due to the abstraction of AutomationML as a meta-metamodel, it is utilised as the basis for the description language synthesis, however AutomationML also does not fulfil all target criteria. On one hand, the description language synthesis is based on the syntax of AutomationML, and on the other hand, the semantics are determined by the context of computer-based I and C in nuclear power plants and structured utilising the general product, function, and location structures of standard IEC 81346. When modelling I and C failure combinations in addition to event sequences, the description language is completed by an event structure, for which CDL is utilised for the conceptualisation and the formalisation is accomplished with PSL. The PSL formalisation allows for implementing the description language in a knowledge-based system, so that automated engineering is enabled. The I and C modelling, as part of the method, is embedded in the IEC 61513 I and C safety life-cycle and is realised in two steps. Consequently, the I and C design can be analysed at both plant and system level. For the I and C design analysis the concepts of the D3-analysis, FTA, ETA, and FMEA are combined. The thesis is concluded with an example applying the description language and method to the modernisation of a reactor protection system; this illustrates the validation of the overall concept developed in this thesis.
Field testing, modelling and analysis of ferroresonance in a high-voltage power system
Jacobson, David Allan Nils
2000-11-01
Catastrophic equipment failures continue to occur today due to ferroresonance even though this phenomenon has been extensively studied over the past ninety years. This thesis is concerned with the tasks of defining where ferroresonance problems can exist in a high voltage power system, of determining methods for displaying safety margins between nonferroresonant and ferroresonant operating regions and improving upon existing ferroresonance simulation techniques. Several different ferroresonant circuits have been modelled and compared with field measurements taken on the Manitoba Hydro 230-kV power system or compared with laboratory measurements including: a de-energized transformer connected to the grading capacitance of an open circuit breaker, a transformer-terminated doublecircuit transmission line and a coupling capacitor voltage transformer. In a high voltage power system, the most prevalent ferroresonance circuit occurs between a de-energized transformer and the grading capacitor of an open circuit breaker. Experimental work has shown that losses in a practical transformer are much larger during ferroresonance oscillation modes than predicted by conventional modelling techniques. A simple switched eddy-current loss resistor is found able to model the losses during subharmonic and fundamental frequency ferroresonance in a laboratory transformer. A major contribution of this work is a new method of visualizing the margin between nonferroresonant and ferroresonant states in a transformer/grading capacitor circuit has been developed. A general set of averaged equations is derived that permit the analysis of an nth order polynomial approximation of the magnetization curve. The location of the saddle points and slope of the stable manifold through the saddle points can be determined for a particular transformer under study. The Limacon of Pascal is found to be a good approximation to the geometric shape of the basin of attraction of the period-1 ferroresonant
Directory of Open Access Journals (Sweden)
Antoni Fonseca i Casas
2016-10-01
Full Text Available Creating a definition of the features and the architecture of a new Energy Management Software (EMS is complex because different professionals will be involved in creating that definition and in using the tool. To simplify this definition and aid in the eventual selection of an existing EMS to fit a specific need, a set of metrics that considers the primary issues and drawbacks of the EMS is decisive. This study proposes a set of metrics to evaluate and compare EMS applications. Using these metrics will allow professionals to highlight the tendencies and detect the drawbacks of current EMS applications and to eventually develop new EMS applications based on the results of the analysis. This study presents a list of the applications to be examined and describes the primary issues to be considered in the development of a new application. This study follows the Systemic Quality Model (SQMO, which has been used as a starting point to develop new EMS, but can also be used to select an existing EMS that fits the goals of a company. Using this type of analysis, we were able to detect the primary features desired in an EMS software. These features are numerically scaled, allowing professionals to select the most appropriate EMS that fits for their purposes. This allows the development of EMS utilizing an iterative and user-centric approach. We can apply this methodology to guide the development of future EMS and to define the priorities that are desired in this type of software.
Directory of Open Access Journals (Sweden)
Suryanto Tri Lathif Mardi
2016-01-01
Full Text Available This study examines the effect of Information Quality, Systems Quality and Service Quality on the user intention to reuse Employee Management Information System (SIMPEG in University in the city of Surabaya, based on the theoretical foundation of DeLone and McLane Information Systems Success (ISS Model. The distribution of questionnaire was conducted to 120 employees of different universities by means of stratified random sampling. The results showed that: (1 there is a significant positive effect of the System Quality on the Quality of Information, (2 there is a significant positive effect of the Information Quality on the Intention to Reuse, information related to the fulfillment of the user’s needs; (3 there is a significant positive effect of the Quality of the Intention on system re-use, the system related to the fulfillment of the needs of users; (4 there is no effect of the Quality of Service to the Intention to Reuse. In the end, the results of this study provide an analysis and advice to The University officials that can be used as a consideration for Information Technology/Information System investment and development in accordance with the Success of Information System and Intention to Reuse model.
National Aeronautics and Space Administration — Stirling Dynamics Inc and the University of Washington propose to develop a MATLAB toolbox for rapid aeroelastic (AE) and aeroservoelastic (ASE) modeling, analysis...
A new approach to real-time reliability analysis of transmission system using fuzzy Markov model
Energy Technology Data Exchange (ETDEWEB)
Tanrioven, M.; Kocatepe, C. [University of Yildiz Technical, Istanbul (Turkey). Dept. of Electrical Engineering; Wu, Q.H.; Turner, D.R.; Wang, J. [Liverpool Univ. (United Kingdom). Dept. of Electrical Engineering and Economics
2004-12-01
To date the studies of power system reliability over a specified time period have used average values of the system transition rates in Markov techniques. [Singh C, Billinton R. System reliability modeling and evaluation. London: Hutchison Educational; 1977]. However, the level of power systems reliability varies from time to time due to weather conditions, power demand and random faults [Billinton R, Wojczynski E. Distributional variation of distribution system reliability indices. IEEE Trans Power Apparatus Systems 1985; PAS-104(11):3152-60]. It is essential to obtain an estimate of system reliability under all environmental and operating conditions. In this paper, fuzzy logic is used in the Markov model to describe both transition rates and temperature-based seasonal variations, which identifies multiple weather conditions such as normal, less stormy, very stormy, etc. A three-bus power system model is considered to determine the variation of system reliability in real-time, using this newly developed fuzzy Markov model (FMM). The results cover different aspects such as daily and monthly reliability changes during January and August. The reliability of the power transmission system is derived as a function of augmentation in peak load level. Finally the variation of the system reliability with weather conditions is determined. (author)
Directory of Open Access Journals (Sweden)
Francisco Rodríguez-Trelles
1998-12-01
Full Text Available Current efforts to study the biological effects of global change have focused on ecological responses, particularly shifts in species ranges. Mostly ignored are microevolutionary changes. Genetic changes may be at least as important as ecological ones in determining species' responses. In addition, such changes may be a sensitive indicator of global changes that will provide different information than that provided by range shifts. We discuss potential candidate systems to use in such monitoring programs. Studies of Drosophila subobscura suggest that its chromosomal inversion polymorphisms are responding to global warming. Drosophila inversion polymorphisms can be useful indicators of the effects of climate change on populations and ecosystems. Other species also hold the potential to become important indicators of global change. Such studies might significantly influence ecosystem conservation policies and research priorities.
Directory of Open Access Journals (Sweden)
Fuyou Guo
2016-12-01
Full Text Available Eco-efficiency is an important sustainable development and circular economy construct that conceptualizes the relationship between industrial output, resource utilization, and environmental impacts. This paper conducts an eco-efficiency analysis for basin industrial systems using the decomposition model approach. Using data on 10 cities in China’s Songhua River basin, we illustrate the evolutionary characteristics and influencing factors of industrial systems’ eco-efficiency. The results indicate that cities in upstream and midstream areas focus on improving resource efficiency, whereas cities in downstream areas focus on improving terminal control efficiency. The results also show that the government plays an increasingly important role in promoting eco-efficiency and that significant differences in the influencing factors exist among the upstream area, midstream area, and downstream area. Our results offer deeper insights into the eco-efficiency of industrial systems and give further hints on how policy-making can help achieve sustainable development, balancing between economic activities and environmental protection.
Introduction of hydrogen in the Norwegian energy system. NorWays - Regional model analysis
Energy Technology Data Exchange (ETDEWEB)
Rosenberg, Eva; Fidje, Audun; Espegren, Kari Aamodt
2008-12-15
The overall aim of the NorWays project has been to provide decision support for the introduction of hydrogen as an energy carrier in the Norwegian energy system. The NorWays project is a research project funded by the Research Council of Norway. An important task has been to develop alternative scenarios and identifying market segments and regions of the Norwegian energy system where hydrogen may play a significant role. The main scenarios in the project have been: Reference: Based on the assumptions of World Energy Outlook with no new transport technologies; HyWays: Basic assumptions with technology costs (H{sub 2}) based on results from the HyWays project; No tax: No taxes on transport energy ('revenue neutral'); CO{sub 2} reduction: Reduced CO{sub 2} emissions by 75% in 2050. Three regional models have been developed and used to analyse the introduction of hydrogen as energy carrier in competition with other alternatives such as natural gas, electricity, district heating and bio fuels.The focus of the analysis has been on the transportation sector. (Author)
Mixed-effects state-space models for analysis of longitudinal dynamic systems.
Liu, Dacheng; Lu, Tao; Niu, Xu-Feng; Wu, Hulin
2011-06-01
The rapid development of new biotechnologies allows us to deeply understand biomedical dynamic systems in more detail and at a cellular level. Many of the subject-specific biomedical systems can be described by a set of differential or difference equations that are similar to engineering dynamic systems. In this article, motivated by HIV dynamic studies, we propose a class of mixed-effects state-space models based on the longitudinal feature of dynamic systems. State-space models with mixed-effects components are very flexible in modeling the serial correlation of within-subject observations and between-subject variations. The Bayesian approach and the maximum likelihood method for standard mixed-effects models and state-space models are modified and investigated for estimating unknown parameters in the proposed models. In the Bayesian approach, full conditional distributions are derived and the Gibbs sampler is constructed to explore the posterior distributions. For the maximum likelihood method, we develop a Monte Carlo EM algorithm with a Gibbs sampler step to approximate the conditional expectations in the E-step. Simulation studies are conducted to compare the two proposed methods. We apply the mixed-effects state-space model to a data set from an AIDS clinical trial to illustrate the proposed methodologies. The proposed models and methods may also have potential applications in other biomedical system analyses such as tumor dynamics in cancer research and genetic regulatory network modeling. © 2010, The International Biometric Society.
Caggiano, Alessandra
2010-01-01
In modern manufacturing industry, the ever-changing turbulent environment as well as the strong competition among companies require manufacturing systems that are easily upgradable and into which new technologies can be readily integrated. Indispensable requirements for modern flexible and reconfigurable manufacturing systems are related to system responsiveness, that enables rapid launch of new product models, fast adjustment of the manufacturing system capacity to market demands, easy integ...
Operator function modeling: An approach to cognitive task analysis in supervisory control systems
Mitchell, Christine M.
1987-01-01
In a study of models of operators in complex, automated space systems, an operator function model (OFM) methodology was extended to represent cognitive as well as manual operator activities. Development continued on a software tool called OFMdraw, which facilitates construction of an OFM by permitting construction of a heterarchic network of nodes and arcs. Emphasis was placed on development of OFMspert, an expert system designed both to model human operation and to assist real human operators. The system uses a blackboard method of problem solving to make an on-line representation of operator intentions, called ACTIN (actions interpreter).
Shipman, D. L.
1972-01-01
The development of a model to simulate the information system of a program management type of organization is reported. The model statistically determines the following parameters: type of messages, destinations, delivery durations, type processing, processing durations, communication channels, outgoing messages, and priorites. The total management information system of the program management organization is considered, including formal and informal information flows and both facilities and equipment. The model is written in General Purpose System Simulation 2 computer programming language for use on the Univac 1108, Executive 8 computer. The model is simulated on a daily basis and collects queue and resource utilization statistics for each decision point. The statistics are then used by management to evaluate proposed resource allocations, to evaluate proposed changes to the system, and to identify potential problem areas. The model employs both empirical and theoretical distributions which are adjusted to simulate the information flow being studied.
Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun
2012-08-01
The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.
DEFF Research Database (Denmark)
Lindblom, Erik Ulfson; Madsen, Henrik; Mikkelsen, Peter Steen
2007-01-01
. With the proposed model and input data, the GLUE analysis show that the total sampled copper mass can be predicted within a range of +/- 50% of the median value ( 385 g), whereas the grey-box analysis showed a prediction uncertainty of less than +/- 30%. Future work will clarify the pros and cons of the two methods...
Uncertainty modelling and analysis of environmental systems: a river sediment yield example
Keesman, K.J.; Koskela, J.; Guillaume, J.H.; Norton, J.P.; Croke, B.; Jakeman, A.
2011-01-01
Abstract: Throughout the last decades uncertainty analysis has become an essential part of environmental model building (e.g. Beck 1987; Refsgaard et al., 2007). The objective of the paper is to introduce stochastic and setmembership uncertainty modelling concepts, which basically differ in the assu
Xiancheng Zheng; Husan Ali; Xiaohua Wu; Haider Zaman; Shahbaz Khan
2017-01-01
In modern distributed energy systems (DES), focus is shifting from the conventional centralized approach towards distributed architectures. However, modeling and analysis of these systems is more complex, as it involves the interface of multiple energy sources with many different type of loads through power electronics converters. The integration of power electronics converters allows distributed renewable energy sources to become part of modern electronics power distribution systems (EPDS). ...
DEFF Research Database (Denmark)
Qin, Lin
1999-01-01
The design of solar domestic hot water system is a complex process, due to characteristics inherent in solar heating technology. Recently, computer simulation has become a widely used technique to improve the understanding of the thermal processes in such systems. This report presents the detailed...... programs or units that were developed in the Ph.D study of " Analysis, Modeling and Optimum Design of Solar Domestic Hot Water Systems"....
Modeling and Dynamic Analysis of Cutterhead Driving System in Tunnel Boring Machine
Directory of Open Access Journals (Sweden)
Wei Sun
2017-01-01
Full Text Available Failure of cutterhead driving system (CDS of tunnel boring machine (TBM often occurs under shock and vibration conditions. To investigate the dynamic characteristics and reduce system vibration further, an electromechanical coupling model of CDS is established which includes the model of direct torque control (DTC system for three-phase asynchronous motor and purely torsional dynamic model of multistage gear transmission system. The proposed DTC model can provide driving torque just as the practical inverter motor operates so that the influence of motor operating behavior will not be erroneously estimated. Moreover, nonlinear gear meshing factors, such as time-variant mesh stiffness and transmission error, are involved in the dynamic model. Based on the established nonlinear model of CDS, vibration modes can be classified into three types, that is, rigid motion mode, rotational vibration mode, and planet vibration mode. Moreover, dynamic responses under actual driving torque and idealized equivalent torque are compared, which reveals that the ripple of actual driving torque would aggravate vibration of gear transmission system. Influence index of torque ripple is proposed to show that vibration of system increases with torque ripple. This study provides useful guideline for antivibration design and motor control of CDS in TBM.
A stochastic process model for life cycle cost analysis of nuclear power plant systems
Van der Weide, J.A.M.; Pandey, M.D.
2013-01-01
The paper presents a general stochastic model to analyze the life cycle cost of an engineering system that is affected by minor but repairable failures interrupting the operation and a major failure that would require the replacement or renewal of the failed system. It is commonly observed that the
Modeling, Analysis, and Design Insights for Shuttle-based Compact Storage Systems
E. Tappia (Elena); D. Roy (Debjit); M.B.M. de Koster (René); M. Melacini (Marco)
2015-01-01
textabstractShuttle-based compact systems are new automated multi-deep unit-load storage systems with lifts that promise both low operational cost and large volume flexibility. In this paper, we develop novel queuing network models to estimate the performance of both single-tier and multi-tier shutt
Lee, Jing-Nang; Lin, Tsung-Min; Chen, Chien-Chih
2014-01-01
This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14 °C, 0006 kg(w)/kg(da) in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system.
Directory of Open Access Journals (Sweden)
Jing-Nang Lee
2014-01-01
Full Text Available This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14°C, 0006 kgw/kgda in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system.
DEFF Research Database (Denmark)
Basit, Abdul; Hansen, Anca Daniela; Sørensen, Poul Ejnar
2014-01-01
. For this purpose, the power system model has been developed that represents the relevant dynamic features of power plants and compensates for power imbalances caused by the forecasting error during critical weather conditions. The regulating power plan, as an input time series for the developed power system model......Secure power system operation of a highly wind power integrated power system is always at risk during critical weather conditions, e.g. in extreme high winds. The risk is even higher when 50% of the total electricity consumption has to be supplied by wind power, as the case for the future Danish...... power system in 2020. This paper analyses and compares the performance of the future Danish power system during extreme wind speeds, where wind power plants are either controlled through a traditional High Wind Shut Down storm controller or a new High Wind Extended Production storm controller...
Modelling and Comparative Performance Analysis of a Time-Reversed UWB System
Directory of Open Access Journals (Sweden)
Popovski K
2007-01-01
Full Text Available The effects of multipath propagation lead to a significant decrease in system performance in most of the proposed ultra-wideband communication systems. A time-reversed system utilises the multipath channel impulse response to decrease receiver complexity, through a prefiltering at the transmitter. This paper discusses the modelling and comparative performance of a UWB system utilising time-reversed communications. System equations are presented, together with a semianalytical formulation on the level of intersymbol interference and multiuser interference. The standardised IEEE 802.15.3a channel model is applied, and the estimated error performance is compared through simulation with the performance of both time-hopped time-reversed and RAKE-based UWB systems.
Energy Technology Data Exchange (ETDEWEB)
Ruth, M.; Diakov, V.; Goldsby, M. E.; Sa, T. J.
2010-12-01
It is commonly accepted that the introduction of hydrogen as an energy carrier for light-duty vehicles involves concomitant technological development of infrastructure elements, such as production, delivery, and consumption, all associated with certain emission levels. To analyze these at a system level, the suite of corresponding models developed by the United States Department of Energy and involving several national laboratories is combined in one macro-system model (MSM). The macro-system model is being developed as a cross-cutting analysis tool that combines a set of hydrogen technology analysis models. Within the MSM, a federated simulation framework is used for consistent data transfer between the component models. The framework is built to suit cross-model as well as cross-platform data exchange and involves features of 'over-the-net' computation.
An Axiomatic Analysis Approach for Large-Scale Disaster-Tolerant Systems Modeling
Directory of Open Access Journals (Sweden)
Theodore W. Manikas
2011-02-01
Full Text Available Disaster tolerance in computing and communications systems refers to the ability to maintain a degree of functionality throughout the occurrence of a disaster. We accomplish the incorporation of disaster tolerance within a system by simulating various threats to the system operation and identifying areas for system redesign. Unfortunately, extremely large systems are not amenable to comprehensive simulation studies due to the large computational complexity requirements. To address this limitation, an axiomatic approach that decomposes a large-scale system into smaller subsystems is developed that allows the subsystems to be independently modeled. This approach is implemented using a data communications network system example. The results indicate that the decomposition approach produces simulation responses that are similar to the full system approach, but with greatly reduced simulation time.
An Axiomatic Analysis Approach for Large-Scale Disaster-Tolerant Systems Modeling
Directory of Open Access Journals (Sweden)
Theodore W. Manikas
2011-02-01
Full Text Available Disaster tolerance in computing and communications systems refers to the ability to maintain a degree of functionality throughout the occurrence of a disaster. We accomplish the incorporation of disaster tolerance within a system by simulating various threats to the system operation and identifying areas for system redesign. Unfortunately, extremely large systems are not amenable to comprehensive simulation studies due to the large computational complexity requirements. To address this limitation, an axiomatic approach that decomposes a large-scale system into smaller subsystems is developed that allows the subsystems to be independently modeled. This approach is implemented using a data communications network system example. The results indicate that the decomposition approach produces simulation responses that are similar to the full system approach, but with greatly reduced simulation time.
Multidisciplinary System Reliability Analysis
Mahadevan, Sankaran; Han, Song; Chamis, Christos C. (Technical Monitor)
2001-01-01
The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code, developed under the leadership of NASA Glenn Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multidisciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.
Russell, Jack; Russell, Barbara
2015-01-01
The goal is to provide a robust and challenging problem statement for a capstone, advanced systems analysis and design course for CIS/MIS/CS majors. In addition to the problem narrative, a representative solution for much of the business modeling deliverables is presented using the UML paradigm. A structured analysis deliverable will be the topic…
Experimental study and modeling of cooling ceiling systems using steady-state analysis
Energy Technology Data Exchange (ETDEWEB)
Fonseca Diaz, Nestor [Thermodynamic Laboratory, University of Liege Belgium, Campus du Sart Tilman, Bat: B49 - P33, B-4000 Liege (Belgium); Universidad Tecnologica de Pereira, Facultad de Ingenieria Mecuanica, AA. 97 Pereira (Colombia); Lebrun, Jean [Thermodynamic Laboratory, University of Liege Belgium, Campus du Sart Tilman, Bat: B49 - P33, B-4000 Liege (Belgium); Andre, Philippe [Departement Sciences et Gestion de l' Environnement, University of Liege Belgium, 185, Avenue de Longwy, B-6700 Arlon (Belgium)
2010-06-15
This article presents the results of an experimental study performed to develop a computational model of cooling ceiling systems. The model considers the cooling ceiling as a fin. Only the dry regime is considered. From ceiling and room dimensions, material description of the cooling ceiling and measurement of supply water mass flow rate and air and water temperatures, the model calculates the cooling ceiling capacity, ceiling surface average temperature and water exhaust temperature. Fin efficiency, mixed convection close to the cooling ceiling (generated by the ventilation system) and panel perforations influence are studied. The theoretical approach gives to the user an appropriate tool for preliminary calculation, design and diagnosis in commissioning processes in order to determine the main operating conditions of the system in cooling mode. A series of experimental results got on four types of cooling ceilings are used in order to validate the model. (author)
An Intrusion Detection System Model Based on Immune Principle and Performance Analysis
Institute of Scientific and Technical Information of China (English)
CHEN Zhi-xian; WANG Ru-chuan; WANG Shao-di; SUN Zhi-xin
2005-01-01
The study of security in computer networks is a key issue,which is a rapidly growing area of interest because of its importance.Main network security problems are analyzed in this paper above all,which currently are confronted with network systems and existing works in intrusion detection.And then an intrusion detection system model based on Immune Principle(IPIDS)is presented.Meanwhile,it expatiates detailed implementation of the methods how to reduce the high false positive and negative alarms of the traditional Intrusion Detection System(IDS).At last a simple simulation is performed on this model just using string match algorithm as binding mechanism.The simulation results indicate that the model can detect malicious activity effectively,and consequently the security and steadiness of the whole network system are improved also.
Matsuura, Tomoaki; Tanimura, Naoki; Hosoda, Kazufumi; Yomo, Tetsuya; Shimizu, Yoshihiro
2017-02-21
To elucidate the dynamic features of a biologically relevant large-scale reaction network, we constructed a computational model of minimal protein synthesis consisting of 241 components and 968 reactions that synthesize the Met-Gly-Gly (MGG) peptide based on an Escherichia coli-based reconstituted in vitro protein synthesis system. We performed a simulation using parameters collected primarily from the literature and found that the rate of MGG peptide synthesis becomes nearly constant in minutes, thus achieving a steady state similar to experimental observations. In addition, concentration changes to 70% of the components, including intermediates, reached a plateau in a few minutes. However, the concentration change of each component exhibits several temporal plateaus, or a quasi-stationary state (QSS), before reaching the final plateau. To understand these complex dynamics, we focused on whether the components reached a QSS, mapped the arrangement of components in a QSS in the entire reaction network structure, and investigated time-dependent changes. We found that components in a QSS form clusters that grow over time but not in a linear fashion, and that this process involves the collapse and regrowth of clusters before the formation of a final large single cluster. These observations might commonly occur in other large-scale biological reaction networks. This developed analysis might be useful for understanding large-scale biological reactions by visualizing complex dynamics, thereby extracting the characteristics of the reaction network, including phase transitions.
Directory of Open Access Journals (Sweden)
A. Gashimov
2013-01-01
Full Text Available The paper considers problems pertaining to modeling and simulation of operational hybrid system modes of the distributed generation comprising conventional sources – modular diesel generators, gas-turbine power units; and renewable sources – wind and solar power plants. Operational modes of the hybrid system have been investigated under conditions of electrical connection with electric power system and in case of its isolated operation. As a consequence
Energy Technology Data Exchange (ETDEWEB)
Lin Qin
1998-12-31
The design of solar domestic hot water (DHW) systems is a complex process, due to characteristics inherent in the solar heating technology. Recently, computer simulation has become a widely used technique to improve the understanding of the thermal processes in such systems. One of the main objects of the Ph.D. study of `Analysis, Modelling and optimum Design of Solar Domestic Hot Water Systems` is to develop and verify programs for carrying out the simulation and evaluation of the dynamic performance of solar DHW systems. During this study, simulation programs for hot water distribution networks and for certain types of solar DHW systems were developed. (au)
Mordecai, Yaniv; Dori, Dov
2017-07-17
The cyber-physical gap (CPG) is the difference between the 'real' state of the world and the way the system perceives it. This discrepancy often stems from the limitations of sensing and data collection technologies and capabilities, and is inevitable at some degree in any cyber-physical system (CPS). Ignoring or misrepresenting such limitations during system modeling, specification, design, and analysis can potentially result in systemic misconceptions, disrupted functionality and performance, system failure, severe damage, and potential detrimental impacts on the system and its environment. We propose CPG-Aware Modeling & Engineering (CPGAME), a conceptual model-based approach to capturing, explaining, and mitigating the CPG. CPGAME enhances the systems engineer's ability to cope with CPGs, mitigate them by design, and prevent erroneous decisions and actions. We demonstrate CPGAME by applying it for modeling and analysis of the 1979 Three Miles Island 2 nuclear accident, and show how its meltdown could be mitigated. We use ISO-19450:2015-Object Process Methodology as our conceptual modeling framework.
Mathematical System Theory and System Modeling
1980-01-01
Choosing models related effectively to the questions to be addressed is a central issue in the craft of systems analysis. Since the mathematical description the analyst chooses constrains the types of issues he candeal with, it is important for these models to be selected so as to yield limitations that are acceptable in view of the questions the systems analysis seeks to answer. In this paper, the author gives an overview of the central issues affecting the question of model choice. To ...
Performance Simulation and Analysis for LTE System Using Human Behavior Queue Model
Directory of Open Access Journals (Sweden)
Tony Tsang
2013-05-01
Full Text Available Understanding the nature of traffic has been a key concern of the researchers particularly over the last two decades and it has been noticed through extensive high quality studies that traffic found in different kinds of IP/wireless IP networks is human operators . Despite the recent findings of real time human behavior in measured traffic from data networks, much of the current understanding of IP traffic modeling is still based on simplistic probability distributed traffic. Unlike most existing studies that areprimarily based on simplistic probabilistic model and traditional scheduling algorithms, this research presents an analytical performance model for real time human behavior queue systems with intelligent task management traffic input scheduled by anovel and promising scheduling mechanism for 4G -LTE system. Our proposed model is substantiated on human behavior queuing system that considers real time of traffic exhibiting homogeneous tasks characteristics. We analyze the model on the basis of newly proposed scheduling scheme for 4G - LTE system. We present closed form expressions of expected response times for real time traffic classes. We develop a discrete event simulator to understand the behavior of real time of arriving tasks traffic under this newly proposed scheduling mechanism for 4G - LTE system . The results indicate that our proposed scheduling algorithm provides preferential treatment to real -time applications such as voice and video but not to that extent that data applications are starving for bandwidth and outperforms all other scheduling schemes that are available in the market.
Modelling, Testing and Analysis of a Regenerative Hydraulic Shock Absorber System
Directory of Open Access Journals (Sweden)
Ruichen Wang
2016-05-01
Full Text Available To improve vehicle fuel economy whilst enhancing road handling and ride comfort, power generating suspension systems have recently attracted increased attention in automotive engineering. This paper presents our study of a regenerative hydraulic shock absorber system which converts the oscillatory motion of a vehicle suspension into unidirectional rotary motion of a generator. Firstly a model which takes into account the influences of the dynamics of hydraulic flow, rotational motion and power regeneration is developed. Thereafter the model parameters of fluid bulk modulus, motor efficiencies, viscous friction torque, and voltage and torque constant coefficients are determined based on modelling and experimental studies of a prototype system. The model is then validated under different input excitations and load resistances, obtaining results which show good agreement between prediction and measurement. In particular, the system using piston-rod dimensions of 50–30 mm achieves recoverable power of 260 W with an efficiency of around 40% under sinusoidal excitation of 1 Hz frequency and 25 mm amplitude when the accumulator capacity is set to 0.32 L with the load resistance 20 Ω. It is then shown that the appropriate damping characteristics required from a shock absorber in a heavy-haulage vehicle can be met by using variable load resistances and accumulator capacities in a device akin to the prototype. The validated model paves the way for further system optimisation towards maximising the performance of regeneration, ride comfort and handling.
Fuß, Hendrik; Dubitzky, Werner; Downes, C. Stephen; Kurth, Mary Jo
2007-01-01
Src family kinases (SFKs) interact with a number of cellular receptors. They participate in diverse signaling pathways and cellular functions. Most of the receptors involved in SFK signaling are characterized by similar modes of regulation. This computational study discusses a general kinetic model of SFK-receptor interaction. The analysis of the model reveals three major ways of SFK activation: release of inhibition by C-terminal Src kinase, weakening of the inhibitory intramolecular phospho...
Hydraulic model analysis of water distribution system, Rockwell International, Rocky Flats, Colorado
Energy Technology Data Exchange (ETDEWEB)
Perstein, J.; Castellano, J.A. [Hughes Associates, Inc., Wheaton, MD (United States)
1989-01-20
Rockwell International requested an analysis of the existing plant site water supply distribution system at Rocky Flats, Colorado, to determine its adequacy. On September 26--29, 1988, Hughes Associates, Inc., Fire Protection Engineers, accompanied by Rocky Flats Fire Department engineers and suppression personnel, conducted water flow tests at the Rocky Flats plant site. Thirty-seven flows from various points throughout the plant site were taken on the existing domestic supply/fire main installation to assure comprehensive and thorough representation of the Rocky Flats water distribution system capability. The analysis was completed in four phases which are described, together with a summary of general conclusions and recommendations.
Wiesner, Margit; Schanding, G Thomas
2013-12-01
Several psychological assessment instruments are based on the assumption of a general construct that is composed of multiple interrelated domains. Standard confirmatory factor analysis is often not well suited for examining the factor structure of such scales. This study used data from 1885 elementary school students (mean age=8.77 years, SD=1.47 years) to examine the factor structure of the Behavioral Assessment System for Children, Second Edition (BASC-2) Behavioral and Emotional Screening System (BESS) Teacher Form that was designed to assess general risk for emotional/behavioral difficulty among children. The modeling sequence included the relatively new exploratory structural equation modeling (ESEM) approach and bifactor models in addition to more standard techniques. Findings revealed that the factor structure of the BASC-2 BESS Teacher Form is multidimensional. Both ESEM and bifactor models showed good fit to the data. Bifactor models were preferred on conceptual grounds. Findings illuminate the hypothesis-generating power of ESEM and suggest that it might not be optimal for instruments designed to assess a predominant general factor underlying the data.
Numerical modelling and analysis of a room temperature magnetic refrigeration system
DEFF Research Database (Denmark)
Petersen, Thomas Frank
This thesis presents a two-dimensional mathematical model of an Active Magnetic Regenerator (AMR) system which is used for magnetic refrigeration at room temperature. The purpose of the model is to simulate a laboratory-scale AMR constructed at Risø National Laboratory. The AMR model geometry...... comprises a regenerator made of parallel plates, which are separated by channels of a heat transfer fluid. The time-dependent model solves the momentum and continuity equations of the flow of the heat transfer fluid and the coupled energy equations of the heat transfer in the regenerator and the fluid....... The AMR performs a cyclic process, and to simulate the AMR refrigeration cycle the model starts from an initial temperature distribution in the regenerator and fluid channel and takes time steps forward in time until the cyclical steady-state is obtained. The model can therefore be used to study both...
Demand System Analysis of the South Korean Beef Market with the Free Trade Demand Model
Lee, Young-Jae; Kennedy, P. Lynn
2008-01-01
In this study a demand system analysis for beef in South Korea is constructed. A free trade demand system was used in which the economic welfare of market participants are maximized. Recognizing implicit discrimination about non-locally sourced beef products, this study deduces market demand equations with respect to consumer preference in order to identify the marginal effect of change consumer preference has on market demand.
Modeling fuzzy state space of reheater system for simulation and analysis
Munirah, W. M. Wan; Ahmad, T.; Ashaari, A.; Abdullah, M. Adib
2014-07-01
Reheater is one of the important heat exchange components in a high capacity power plant of a boiler system. The aim of this study is to improve heat transfer of a reheater system. The method is to maximize steam production and at the same time, keeping variables within constraints. Fuzzy arithmetic is a powerful tool used to solve engineering problems with uncertain parameters. Therefore, in order to determine heat transfer efficiency, the state space of reheater is simulated using fuzzy arithmetic by taking into account the uncertainties in the reheater system. The uncertain model parameters and the model inputs are represented by fuzzy numbers with their shape derived from quasi-Gaussian function. Finally, this paper discusses how the mathematical model can be manipulated in order to produce maximum heat transfer with least loss of energy. Furthermore, the improvement of the reheater efficiency and the quantification of the heat supplied parameters are presented in this paper.
Communicating systems with UML 2 modeling and analysis of network protocols
Barrera, David Garduno
2013-01-01
This book gives a practical approach to modeling and analyzing communication protocols using UML 2. Network protocols are always presented with a point of view focusing on partial mechanisms and starting models. This book aims at giving the basis needed for anybody to model and validate their own protocols. It follows a practical approach and gives many examples for the description and analysis of well known basic network mechanisms for protocols.The book firstly shows how to describe and validate the main protocol issues (such as synchronization problems, client-server interactions, layer
Stability Analysis and H∞ Model Reduction for Switched Discrete-Time Time-Delay Systems
Directory of Open Access Journals (Sweden)
Zheng-Fan Liu
2014-01-01
Full Text Available This paper is concerned with the problem of exponential stability and H∞ model reduction of a class of switched discrete-time systems with state time-varying delay. Some subsystems can be unstable. Based on the average dwell time technique and Lyapunov-Krasovskii functional (LKF approach, sufficient conditions for exponential stability with H∞ performance of such systems are derived in terms of linear matrix inequalities (LMIs. For the high-order systems, sufficient conditions for the existence of reduced-order model are derived in terms of LMIs. Moreover, the error system is guaranteed to be exponentially stable and an H∞ error performance is guaranteed. Numerical examples are also given to demonstrate the effectiveness and reduced conservatism of the obtained results.
Dynamic modeling and analysis of axial vibration of a coupled propeller and shaft system
Energy Technology Data Exchange (ETDEWEB)
Li, Chenyang; Huang, Xiuchang; Hua, Hongxing [Shanghai Jiao Tong University, Shanghai (China)
2016-07-15
The dynamic and acoustic characteristics of a coupled propeller and shaft system which is modeled by the transfer matrix method are studied. The elasticity of the propeller is taken into consideration by employing the equivalent reduced modeling method. Thus the influence of the elastic propeller on the vibro-acoustic responses of the coupled system is investigated. To reduce the axial vibration of the coupled propeller-shaft system, the influence and location of the vibration isolator on the structural and acoustic responses is presented. Simulation results demonstrate that utilizing the relationship between the natural frequency of the propeller and the resonance frequency range of the shaft can control the vibration of the coupled system without other vibration control method. Utilizing a vibration isolator is another effective way to control vibration. The optimal position for the isolator installed between the shaft and the thrust bearing is investigated.
Stability analysis of multi-compartment models for cell production systems
Nakata Y.; Getto P.; Marciniak-Czochra A.; Alarcon T.
2012-01-01
We study two-and three-compartment models of a hierarchical cell production system with cell division regulated by the level of mature cells. We investigate the structure of equilibria with respect to parameters as well as local stability properties for the equilibria. To interpret the results we adapt the concept of reproduction numbers, which is well known in ecology, to stem cell population dynamics. In the two-compartment model, the positive equilibrium is stable wherever it exists. In th...
Data, analysis and modeling of physical properties for process designof systems involving lipids
DEFF Research Database (Denmark)
Cunico, Larissa; Ceriani, Roberta; Sarup, Bent
2013-01-01
Pure component and mixture properties are necessary for synthesis, design, and analysis of processes forthe production of edible oils, fats, biodiesel, and other lipids. The lack of measured data for these systemsmakes it necessary to develop reliable predictive models based on limited data. We...
A threat-vulnerability based risk analysis model for cyber physical system security
CSIR Research Space (South Africa)
Ledwaba, Lehlogonolo
2017-01-01
Full Text Available processes leaves CPSs vulnerable to security attacks. A threat-vulnerability based risk model is developed through a detailed analysis of CPS security attack structures and threats. The Stuxnet malware attack is used to test the viability of the proposed...
Modelling and Analysis for Cyber-Physical Systems: An SMT-based approach
DEFF Research Database (Denmark)
Dung, Phan Anh
, better designs have positive impacts on the product quality, development time and price, etc. We developed tools, theories and techniques that make use of SMT solving as a back-end engine for analysis and employ Duration Calculus as a front-end technology for modelling. The proposed techniques have been...
Luan, Jing; Willett, Terrence
This paper discusses data mining--an end-to-end (ETE) data analysis tool that is used by researchers in higher education. It also relates data mining and other software programs to a brand new concept called "Knowledge Management." The paper culminates in the Tier Knowledge Management Model (TKMM), which seeks to provide a stable…
Aggarwal, Anil Kr.; Kumar, Sanjeev; Singh, Vikram
2017-08-01
The binary states, i.e., success or failed state assumptions used in conventional reliability are inappropriate for reliability analysis of complex industrial systems due to lack of sufficient probabilistic information. For large complex systems, the uncertainty of each individual parameter enhances the uncertainty of the system reliability. In this paper, the concept of fuzzy reliability has been used for reliability analysis of the system, and the effect of coverage factor, failure and repair rates of subsystems on fuzzy availability for fault-tolerant crystallization system of sugar plant is analyzed. Mathematical modeling of the system is carried out using the mnemonic rule to derive Chapman-Kolmogorov differential equations. These governing differential equations are solved with Runge-Kutta fourth-order method.
Aggarwal, Anil Kr.; Kumar, Sanjeev; Singh, Vikram
2016-08-01
The binary states, i.e., success or failed state assumptions used in conventional reliability are inappropriate for reliability analysis of complex industrial systems due to lack of sufficient probabilistic information. For large complex systems, the uncertainty of each individual parameter enhances the uncertainty of the system reliability. In this paper, the concept of fuzzy reliability has been used for reliability analysis of the system, and the effect of coverage factor, failure and repair rates of subsystems on fuzzy availability for fault-tolerant crystallization system of sugar plant is analyzed. Mathematical modeling of the system is carried out using the mnemonic rule to derive Chapman-Kolmogorov differential equations. These governing differential equations are solved with Runge-Kutta fourth-order method.
Band, Leah R; Fozard, John A; Godin, Christophe; Jensen, Oliver E; Pridmore, Tony; Bennett, Malcolm J; King, John R
2012-10-01
Over recent decades, we have gained detailed knowledge of many processes involved in root growth and development. However, with this knowledge come increasing complexity and an increasing need for mechanistic modeling to understand how those individual processes interact. One major challenge is in relating genotypes to phenotypes, requiring us to move beyond the network and cellular scales, to use multiscale modeling to predict emergent dynamics at the tissue and organ levels. In this review, we highlight recent developments in multiscale modeling, illustrating how these are generating new mechanistic insights into the regulation of root growth and development. We consider how these models are motivating new biological data analysis and explore directions for future research. This modeling progress will be crucial as we move from a qualitative to an increasingly quantitative understanding of root biology, generating predictive tools that accelerate the development of improved crop varieties.
Surface analysis of model systems: From a metal-graphite interface to an intermetallic catalyst
Energy Technology Data Exchange (ETDEWEB)
Kwolek, Emma J. [Iowa State Univ., Ames, IA (United States)
2016-10-25
This thesis summarizes research completed on two different model systems. In the first system, we investigate the deposition of the elemental metal dysprosium on highly-oriented pyrolytic graphite (HOPG) and its resulting nucleation and growth. The goal of this research is to better understand the metal-carbon interactions that occur on HOPG and to apply those to an array of other carbon surfaces. This insight may prove beneficial to developing and using new materials for electronic applications, magnetic applications and catalysis.
Integrated analysis environment for high impact systems
Energy Technology Data Exchange (ETDEWEB)
Martinez, M. [Sandia National Labs., Albuquerque, NM (United States); Davis, J.; Scott, J.; Sztipanovits, J.; Karsai, G. [Vanderbilt Univ., Nashville, TN (United States). Measurement and Computing Systems Lab.
1998-02-01
Modeling and analysis of high consequence, high assurance systems requires special modeling considerations. System safety and reliability information must be captured in the models. Previously, high consequence systems were modeled using separate, disjoint models for safety, reliability, and security. The MultiGraph Architecture facilitates the implementation of a model integrated system for modeling and analysis of high assurance systems. Model integrated computing allows an integrated modeling technique to be applied to high consequence systems. Among the tools used for analyzing safety and reliability are a behavioral simulator and an automatic fault tree generation and analysis tool. Symbolic model checking techniques are used to efficiently investigate the system models. A method for converting finite state machine models to ordered binary decision diagrams allows the application of symbolic model checking routines to the integrated system models. This integrated approach to modeling and analysis of high consequence systems ensures consistency between the models and the different analysis tools.
Modeling, Design and Analysis of a Electrodynamic Levitation System by Considering the Skin Effect
Directory of Open Access Journals (Sweden)
Mohammad Rajabi Sabadani
2016-01-01
Full Text Available In this paper, lift and drag forces of permanent-magnet electrodynamic suspension (PMEDS System have been studied by considering the skin effect. Electrodynamic suspension is based on repulsive force between two magnetic fields with the same polarity. In this research the electrodynamic suspension system consists of a moving permanent magnet block levitated over a flat conducting plate with 2 mm thickness. At first, the analytical model of the PMEDS is proposed. For this propose, permanent magnet poles are modeled by the current sheets. Then the eddy current is calculated on aluminum sheet by considering the skin effect. Finally, the lift and drag forces are calculated in difference speed. The 2D finite element method is utilized to investigate the effect of speed variations on the performance of PMEDS at two different airgap. Two-dimensional finite element model, the accuracy of proposed analytical model is validated. The results of the finite element method are compared with results obtained by analytical model. It shows the accuracy of the analytical model in the estimation of the lift and drag forces of an electrodynamic suspension system.
A DC-DC Converter Efficiency Model for System Level Analysis in Ultra Low Power Applications
Directory of Open Access Journals (Sweden)
Benton H. Calhoun
2013-06-01
Full Text Available This paper presents a model of inductor based DC-DC converters that can be used to study the impact of power management techniques such as dynamic voltage and frequency scaling (DVFS. System level power models of low power systems on chip (SoCs and power management strategies cannot be correctly established without accounting for the associated overhead related to the DC-DC converters that provide regulated power to the system. The proposed model accurately predicts the efficiency of inductor based DC-DC converters with varying topologies and control schemes across a range of output voltage and current loads. It also accounts for the energy and timing overhead associated with the change in the operating condition of the regulator. Since modern SoCs employ power management techniques that vary the voltage and current loads seen by the converter, accurate modeling of the impact on the converter efficiency becomes critical. We use this model to compute the overall cost of two power distribution strategies for a SoC with multiple voltage islands. The proposed model helps us to obtain the energy benefits of a power management technique and can also be used as a basis for comparison between power management techniques or as a tool for design space exploration early in a SoC design cycle.
Spears, Janine L.; Parrish, James L., Jr.
2013-01-01
This teaching case introduces students to a relatively simple approach to identifying and documenting security requirements within conceptual models that are commonly taught in systems analysis and design courses. An introduction to information security is provided, followed by a classroom example of a fictitious company, "Fun &…
Spears, Janine L.; Parrish, James L., Jr.
2013-01-01
This teaching case introduces students to a relatively simple approach to identifying and documenting security requirements within conceptual models that are commonly taught in systems analysis and design courses. An introduction to information security is provided, followed by a classroom example of a fictitious company, "Fun &…
Fully Burdened Cost of Energy Analysis: A Model for Marine Corps Systems
2013-01-30
and comic relief necessary during the more stressful times. I would also like to thank my extended family for instilling the value of education in me... history . After graduating from the Naval Postgraduate School, he will be reporting to the Cost and Analysis branch of Marine Corps Systems Command in
DEFF Research Database (Denmark)
Tjell, Simon; Lassen, Kristian Bisgaard
2008-01-01
In this paper, we describe a formal foundation for a specialized approach to automatically checking traces against real-time requirements. The traces are obtained from simulation of Coloured Petri Net (CPN) models of reactive systems. The real-time requirements are expressed in terms...... of a derivative of UML 2.0 high-level Sequence Diagrams. The automated requirement checking is part of a bigger tool framework in which VDM++ is applied to automatically generate initial CPN models based on Problem Diagrams. These models are manually enhanced to provide behavioral descriptions of the environment...
Parameter analysis for a mathematical model of the immune system in leukemia
Safta, Carmen Anca; Balea, Silvia; Halanay, Andrei; Neamtu, Mihaela
2014-12-01
Starting from a mathematical model which describes the dynamics of Chronic Myelogenous Leukemia (CML) when the action of different cell lines of the immune system is considered, the aim of the paper is to analyze the parameters influence in CML evolution. The model consists of seven delay differential equations with seven delays. The physiological processes are modeled using feedback functions so the variation of their coefficients changes the disease's evolution. Numerical simulations will be used to observe the evolution of the disease and to determine the possible treatment options.
Wang, Yuezong; Zhao, Zhizhong; Wang, Junshuai
2016-04-01
We present a novel and high-precision microscopic vision modeling method, which can be used for 3D data reconstruction in micro-gripping system with stereo light microscope. This method consists of four parts: image distortion correction, disparity distortion correction, initial vision model and residual compensation model. First, the method of image distortion correction is proposed. Image data required by image distortion correction comes from stereo images of calibration sample. The geometric features of image distortions can be predicted though the shape deformation of lines constructed by grid points in stereo images. Linear and polynomial fitting methods are applied to correct image distortions. Second, shape deformation features of disparity distribution are discussed. The method of disparity distortion correction is proposed. Polynomial fitting method is applied to correct disparity distortion. Third, a microscopic vision model is derived, which consists of two models, i.e., initial vision model and residual compensation model. We derive initial vision model by the analysis of direct mapping relationship between object and image points. Residual compensation model is derived based on the residual analysis of initial vision model. The results show that with maximum reconstruction distance of 4.1mm in X direction, 2.9mm in Y direction and 2.25mm in Z direction, our model achieves a precision of 0.01mm in X and Y directions and 0.015mm in Z direction. Comparison of our model with traditional pinhole camera model shows that two kinds of models have a similar reconstruction precision of X coordinates. However, traditional pinhole camera model has a lower precision of Y and Z coordinates than our model. The method proposed in this paper is very helpful for the micro-gripping system based on SLM microscopic vision.
Parametric analysis of stand-alone residential photovoltaic systems and the SOLSTOR simulation model
Caskey, D. L.; Aronson, E. A.; Murphy, K. D.
Grid-connected residential photovoltaic (PV) systems have been studied in great detail during the past few years. However, stand-alone systems have received considerably less attention. This paper describes the results of an evaluation of the economic feasibility of stand-alone systems. The SOLSTOR simulation program, developed by Sandia, was the primary analysis tool. The results indicate that stand-alone PV systems offer considerable economic advantage over the fossil-fueled generator systems. This is true even with no escalation of fuel prices, with PV array costs of twice the 1986 DOE goal, with present day battery costs, and in the Northeast as well as in the Southwest part of the United States. The on-site generator was generally used less than 1400 hours per year, and in fact can be eliminated in many cases in the Southwest.
2015-06-04
Uncertainty for a Macro-Fiber Composite Model,” IFAC Workshop on Control of Systems Governed through Partial Differential Equations (CPDE), Paris, France...Analysis of Partial Differential Equations , San Diego, CA, November 16, 2011. • Invited Presentation: 50th IEEE Conference on Decision and Control...Workshop on Control of Systems Governed through Partial Differential Equations (CPDE), Paris, France, 2013. [9] Z. Hu, R.C. Smith, N. Burch, M. Hays and
Institute of Scientific and Technical Information of China (English)
CHENMing; TANGTiantong; CHENGuangde; ZHANGPenghui
2003-01-01
Analysis of electro - electro power transmission efficiency of SAW IDTs (Surface-acoustic-wave Interdigital transducers) system is studied, which is based on the newly developed simple six-port equivalent circuit model for SAW IDTs. The application of this method to the SAW IDTs with 80 fingers system on Y-Z LiNbO3 for acousto-optical interaction is also investigated, and it shows that the calculated result is in agreement with experimental one.
Simulation and analysis of a model dinoflagellate predator-prey system
Mazzoleni, M. J.; Antonelli, T.; Coyne, K. J.; Rossi, L. F.
2015-12-01
This paper analyzes the dynamics of a model dinoflagellate predator-prey system and uses simulations to validate theoretical and experimental studies. A simple model for predator-prey interactions is derived by drawing upon analogies from chemical kinetics. This model is then modified to account for inefficiencies in predation. Simulation results are shown to closely match the model predictions. Additional simulations are then run which are based on experimental observations of predatory dinoflagellate behavior, and this study specifically investigates how the predatory dinoflagellate Karlodinium veneficum uses toxins to immobilize its prey and increase its feeding rate. These simulations account for complex dynamics that were not included in the basic models, and the results from these computational simulations closely match the experimentally observed predatory behavior of K. veneficum and reinforce the notion that predatory dinoflagellates utilize toxins to increase their feeding rate.
Frequency domain model for transient analysis of lightning protection systems of buildings.
Gómez, Pablo
2016-10-01
A frequency domain modeling approach for lightning protection systems (LPS) of buildings is described and validated in this paper. The model is based on a 2-port transmission line representation of each conductor, and the further assembling of a network representing the complete structure. Horizontal and vertical conductors are modeled using formulas based on the complex images method, in order to take into account frequency dependence. Variation of electrical parameters with height is also considered for vertical conductors. This is accomplished by means of a non-uniform modeling approach based on conductor subdivision and cascaded connection of chain matrices computed for each segment. The results from the model are validated by means of comparisons with measurements reported elsewhere, as well as simulations using PSCAD/EMTDC.
Institute of Scientific and Technical Information of China (English)
Wang Xuanyin; Xiao Baoping; Pan Feng
2003-01-01
A dual-CCD simulating human eyes and neck (DSHEN) vision system is put forward. Its structure and principle are introduced. The DSHEN vision system can perform some movements simulating human eyes and neck by means of four rotating joints, and realize precise object recognizing and distance measuring in all orientations. The mathematic model of the DSHEN vision system is built, and its movement equation is solved. The coordinate error and measure precision affected by the movement parameters are analyzed by means of intersection measuring method. So a theoretic foundation for further research on automatic object recognizing and precise target tracking is provided.
Vinayak S. Dixit*, Sachin C. Borse
2017-01-01
The three main objectives that a suspension system of an automobile must satisfy are ride comfort, vehicle handling and suspension working space. Ride comfort is directly related to the vehicle acceleration experienced by the driver and the passengers. Lesser vertical acceleration, higher is the level of comfort. The aim of the Project was to design and analyze the semi active suspension system models using skyhook, ground hook and hybrid control for quarter car. The project work includes mod...
Adrian Ioana; Tiberiu Socaciu
2013-01-01
The article presents specific aspects of management and models for economic analysis. Thus, we present the main types of economic analysis: statistical analysis, dynamic analysis, static analysis, mathematical analysis, psychological analysis. Also we present the main object of the analysis: the technological activity analysis of a company, the analysis of the production costs, the economic activity analysis of a company, the analysis of equipment, the analysis of labor productivity, the anal...
Multifractals of central place systems: models, dimension spectrums, and empirical analysis
Chen, Yanguang
2013-01-01
Central place systems have been demonstrated to possess self-similar patterns in both the theoretical and empirical perspectives. A central place fractal can be treated as a monofractal with a single scaling process. However, in the real world, a system of human settlements is a complex network with multi-scaling processes. The simple fractal central place models are not enough to interpret the spatial patterns and evolutive processes of urban systems. It is necessary to construct multi-scaling fractal models of urban places. Based on the postulate of intermittent space filling, two typical multifractal models of central places are proposed in this paper. One model is put forward to reflect the process of spatial convergence (aggregation), and the generalized correlation dimension varies from 0.7306 to 1.3181; the other model is presented to describe the process of spatial divergence (diffusion), the generalized correlation dimension ranges from 1.6523 to 1.7118. As a case study, an analogy is drawn between t...
Directory of Open Access Journals (Sweden)
Gustavo Betarte
2015-12-01
Full Text Available In this work we investigate the security of security-critical applications, i.e. applications in which a failure may produce consequences that are unacceptable. We consider three areas: mobile devices, virtualization platforms, and domain name systems. The Java Micro Edition platform defines the Mobile Information Device Profile (MIDP to facilitate the development of applications for mobile devices, like cell phones and PDAs. We first study and compare formally several variants of the security model specified by MIDP to access sensitive resources of a mobile device. Hypervisors allow multiple guest operating systems to run on shared hardware, and offer a compelling means of improving the security and the flexibility of software systems. In this work we present a formalization of an idealized model of a hypervisor. We establish (formally that the hypervisor ensures strong isolation properties between the different operating systems, and guarantees that requests from guest operating systems are eventually attended. We show also that virtualized platforms are transparent, i.e. a guest operating system cannot distinguish whether it executes alone or together with other guest operating systems on the platform. The Domain Name System Security Extensions (DNSSEC is a suite of specifications that provides origin authentication and integrity assurance services for DNS data. We finally introduce a minimalistic specification of a DNSSEC model which provides the grounds needed to formally state and verify security properties concerning the chain of trust of the DNSSEC tree. We develop all our formalizations in the Calculus of Inductive Constructions --formal language that combines a higher-order logic and a richly-typed functional programming language-- using the Coq proof assistant.
Energy Technology Data Exchange (ETDEWEB)
Fedorov, Alexey V. [Yale Univ., New Haven, CT (United States)
2015-01-14
The central goal of this research project was to understand the mechanisms of decadal and multi-decadal variability of the Atlantic Meridional Overturning Circulation (AMOC) as related to climate variability and abrupt climate change within a hierarchy of climate models ranging from realistic ocean models to comprehensive Earth system models. Generalized Stability Analysis, a method that quantifies the transient and asymptotic growth of perturbations in the system, is one of the main approaches used throughout this project. The topics we have explored range from physical mechanisms that control AMOC variability to the factors that determine AMOC predictability in the Earth system models, to the stability and variability of the AMOC in past climates.
Performance Analysis and Modelling of a Radio Frequency Energy Harvesting System
Directory of Open Access Journals (Sweden)
CIRSTEA, C.
2013-02-01
Full Text Available The development of autonomous battery powered systems which can be deployed in inaccessible locations for sensing applications has determined the development of various energy harvesting systems. Such an energy harvester is the one developed by Powercast which can convert the energy of radio frequency signals into useful power. A model of the harvested power can prove to be a useful tool for simulation purposes as it can provide, to some extent, prior knowledge of available energy resources when optimally deploying sensor networks. To obtain an accurate model of the harvested energy we have developed an experimental setup which has been used to determine the harvested power in two different environments, a hallway and a parking lot. We have developed the experimental setup to determine the amount of power available at the output of the radio frequency harvester which consists of a current measurement system and a data acquisition system. We have also modeled through simulations the harvested power based on the characteristics of the transmitter and receiver antennas and those of the environment. We have compared the results obtained through in field measurement with the ones obtained through simulation and we have shown that within certain margins of error of maximum 2 dBm one can successfully predict the amount of energy the system can harvest. However the RF-DC and Boost converter efficiency are also key factors in the quantity of harvested energy.
DEFF Research Database (Denmark)
Nguyen, Tuong-Van; Elmegaard, Brian
2016-01-01
Natural gas liquefaction systems are based on refrigeration cycles – they consist of the same operations such as heat exchange, compression and expansion, but they have different layouts, components and working fluids. The design of these systems requires a preliminary simulation and evaluation...... of their performance. However, the thermodynamic models used for this purpose are characterised by different mathematical formulations, ranges of application and levels of accuracy. This may lead to inconsistent results when estimating hydrocarbon properties and assessing the efficiency of a given process. This paper...... presents a thorough comparison of six equations of state widely used in the academia and industry, including the GERG-2008 model, which has recently been adopted as an ISO standard for natural gases. These models are used to (i) estimate the thermophysical properties of a Danish natural gas, (ii) simulate...
Energy Technology Data Exchange (ETDEWEB)
Ernest A. Mancini; Paul Aharon; Donald A. Goddard; Roger Barnaby
2006-02-28
The principal research effort for Year 3 of the project is basin modeling and petroleum system identification, comparative basin evaluation and resource assessment. In the first six (6) months of Year 3, the research focus is on basin modeling and petroleum system identification and the remainder of the year the emphasis is on the comparative basin evaluation and resource assessment. No major problems have been encountered to date, and the project is on schedule. The principal objectives of the project are to develop through basin analysis and modeling the concept that petroleum systems acting in a basin can be identified through basin modeling and to demonstrate that the information and analysis resulting from characterizing and modeling of these petroleum systems in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin can be used in providing a more reliable and advanced approach for targeting stratigraphic traps and specific reservoir facies within a geologic system and in providing a refined assessment of undiscovered and underdeveloped reservoirs and associated oil and gas resources.
Modeling and analysis of the EDS Maglev system with the Halbach magnet array
Ko, Wonsuk
The magnetic field analysis based on the wavelet transform is performed. The Halbach array magnetic field analysis has been studied using many methods such as magnetic scalar potential, magnetic vector potential, Fourier analysis and Finite Element Methods. But these analyses cannot identify a transient oscillation at the beginning stage of levitation. The wavelet transform is used for analyzing the transient oscillatory response of an EDS Maglev system. The proposed scheme explains the under-damped dynamics that results from the cradle's dynamic response to the irregular distribution of the magnetic field. It suggests this EDS Maglev system that responds to a vertical repulsive force could be subject to such instability at the beginning stage of a low levitation height. The proposed method is useful in analyzing instabilities at the beginning stage of levitation height. A controller for the EDS maglev system with the Halbach array magnet is designed for the beginning stage of levitation and after reaching the defined levitation height. To design a controller for the EDS system, two different stages are suggested. Before the object reaches a stable position and after it has reached a stable position. A stable position can be referred to as a nominal height. The former is the stage I and the latter is the stage II. At the stage I, to achieve a nominal height the robust controller is investigated. At the stage II, both translational and rotational motions are considered for the control design. To maintain system stability, damping control as well as LQR control are performed. The proposed method is helpful to understand system dynamics and achieve system stability.
Techno-Economic Modeling and Analysis of Redox Flow Battery Systems
Directory of Open Access Journals (Sweden)
Jens Noack
2016-08-01
Full Text Available A techno-economic model was developed to investigate the influence of components on the system costs of redox flow batteries. Sensitivity analyses were carried out based on an example of a 10 kW/120 kWh vanadium redox flow battery system, and the costs of the individual components were analyzed. Particular consideration was given to the influence of the material costs and resistances of bipolar plates and energy storage media as well as voltages and electric currents. Based on the developed model, it was possible to formulate statements about the targeted optimization of a developed non-commercial vanadium redox flow battery system and general aspects for future developments of redox flow batteries.
Energy Technology Data Exchange (ETDEWEB)
Haihua Zhao; Ling Zou; Hongbin Zhang; David Andrs; Richard Martineau
2014-04-01
The reactor core isolation cooling (RCIC) system in a boiling water reactor (BWR) provides makeup water to the reactor vessel for core cooling when the main steam lines are isolated and the normal supply of water to the reactor vessel is lost. It was one of the very few safety systems still available during the Fukushima Daiichi accidents after the tsunamis hit the plants and the system successfully delayed the core meltdown for a few days for unit 2 & 3. Therefore, detailed models for RCIC system components are indispensable to understand extended station black-out accidents (SBO) for BWRs. As part of the effort to develop the new generation reactor system safety analysis code RELAP-7, major components to simulate the RCIC system have been developed. This paper describes the models for those components such as turbine, pump, and wet well. Selected individual component test simulations and a simplified SBO simulation up to but before core damage is presented. The successful implementation of the simplified RCIC and wet well models paves the way to further improve the models for safety analysis by including more detailed physical processes in the near future.
Directory of Open Access Journals (Sweden)
Johan Muliadi Kerta
2013-05-01
Full Text Available The success of implementation of information system in an organization will supportthe organization in the process of achieving goals. Successful information system will support theorganization's day-to-day operations, so that problem can be resolved more quickly and easily. Theinformation system which has been developed and implemented is also necessary to measure thematurity level. Therefore, it can determine whether the implementation of information systemsmade in accordance with the goals of the organization. Measuring the success of informationsystems used the DeLone and McLean IS success model. To measure the maturity level ofinformation systems used COBIT (Control Objectives for Information and related Technologyframeworks that provides best practices for IT governance and control. The results of this analysiswill assist and support the IT team in order to develop and build information systems that better fitthe needs and goals of the organization.
Samad, Noor Asma Fazli Abdul; Sin, Gürkan; Gernaey, Krist V; Gani, Rafiqul
2013-11-01
This paper presents the application of uncertainty and sensitivity analysis as part of a systematic model-based process monitoring and control (PAT) system design framework for crystallization processes. For the uncertainty analysis, the Monte Carlo procedure is used to propagate input uncertainty, while for sensitivity analysis, global methods including the standardized regression coefficients (SRC) and Morris screening are used to identify the most significant parameters. The potassium dihydrogen phosphate (KDP) crystallization process is used as a case study, both in open-loop and closed-loop operation. In the uncertainty analysis, the impact on the predicted output of uncertain parameters related to the nucleation and the crystal growth model has been investigated for both a one- and two-dimensional crystal size distribution (CSD). The open-loop results show that the input uncertainties lead to significant uncertainties on the CSD, with appearance of a secondary peak due to secondary nucleation for both cases. The sensitivity analysis indicated that the most important parameters affecting the CSDs are nucleation order and growth order constants. In the proposed PAT system design (closed-loop), the target CSD variability was successfully reduced compared to the open-loop case, also when considering uncertainty in nucleation and crystal growth model parameters. The latter forms a strong indication of the robustness of the proposed PAT system design in achieving the target CSD and encourages its transfer to full-scale implementation.
Stoianov, Nikolai
2010-01-01
This paper presents one suggestion that comprises the authors' experience in development and implementation of systems for information security in the Automated Information Systems of the Bulgarian Armed Forces. The architecture of risk analysis and assessment system for the communication and information system's information security (CIS IS) has been presented. E-net model of "Defining" Subsystem as a tool that allows to examine the subsystems is proposed as well. Such approach can be applied successfully for communication and information systems in the business field.
Numerical analysis and centrifugal modeling of LNAPLs transport in subsurface system
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The transport of non-aqueous phase liquids (NAPLs) in unsaturated soils and groundwater is an important research topic in geo-environmental engineering. In this paper, the mechanism of light NAPLs (LNAPLs) transport in subsurface system is briefly introduced, and the mass transport equations, fluid flow equations, and the constitutive model of relative permeability - saturation - capillary pressure are discussed. Then the numerical method is introduced to simulate the multiphase flow problems in porous media, and the tempospatial distribution of LNAPLs is obtained. Moreover, different boundary conditions are employed in numerical simulation to investigate its effect on transport behavior. To verify the numerical data, centrifugal tests are conducted to model the LNAPLs migration in unsaturated soils and groundwater. The calculation results are agreeable with the experimental findings of centrifugal modeling, which indicates that LNAPLs from leaking point move downwards due to gravity force, and form a high concentration zone above the capillary fringe, and then spread out laterally along the groundwater table. Some LNAPL enters groundwater system to further migrate. The combination of numerical simulation and centrifuge modeling can be a useful means to study the transport behavior of LNAPLs in subsurface system.
DEFF Research Database (Denmark)
Serban, Ioan; Teodorescu, Remus; Marinescu, Corneliu
2013-01-01
is on autonomous MGs that dynamically behave similarly to the classical power systems. This is the systems case with classical distributed generators (DGs), but which can also contain renewable energy sources (RESs) in a certain penetration level. During MG islanded operation, the local generators take over most...... with both inertial response and an adaptive droop characteristic during battery state-of-charge limitations. The conducted analysis is accomplished by adopting aggregated models for the involved control mechanisms. The developed model is analysed in frequency domain, whereas an experimental test bench...
Modelling and Analysis of Distributed Energy Systems with Respect to Sustainable Energy
DEFF Research Database (Denmark)
Juul, Nina
, that it turns out to be most profitable to invest in enough wind to more than cover the electrified transport in Denmark. This holds, both when modelling Denmark as an isolated country, and when including the interactions between the Nordic countries. Furthermore, analyses show that fuel cell electric vehicles......Climate change and CO2 emissions is an important issue on the agenda of many politicians. Trying to decrease CO2 emissions, influences transportation, power production, etc. The power system is characterised by an increasing amount of renewables, with one of the most expanding renewable power...... also come from the road transport system. Counting for 24% of the CO2 emissions in Denmark in 2009, the road transport system needs to move towards, e.g. electric drive vehicles. However, the electric drive vehicles are also demanding electricity from the power system. This brings both challenges...
Security analysis of chaotic communication systems based on Volterra-Wiener-Korenberg model
Energy Technology Data Exchange (ETDEWEB)
Lei Min [State Key Lab of Vibration, Shock and Noise, Shanghai Jiao Tong University, Shanghai 200030 (China)] e-mail: leimin@sjtu.edu.cn; Meng Guang [State Key Lab of Vibration, Shock and Noise, Shanghai Jiao Tong University, Shanghai 200030 (China); Feng Zhengjin [Institute of Mechatronic Control System, Shanghai Jiao Tong University, Shanghai 200030 (China)
2006-04-01
Pseudo-randomicity is an important cryptological characteristic for proof of encryption algorithms. This paper proposes a nonlinear detecting method based on Volterra-Wiener-Korenberg model and suggests an autocorrelation function to analyze the pseudo-randomicity of chaotic secure systems under different sampling interval. The results show that: (1) the increase of the order of the chaotic transmitter will not necessarily result in a high degree of security; (2) chaotic secure systems have higher and stronger pseudo-randomicity at sparse sampling interval due to the similarity of chaotic time series to the noise; (3) Volterra-Wiener-Korenberg method can also give a further appropriate sparse sampling interval for improving the security of chaotic secure communication systems. For unmasking chaotic communication systems, the Volterra-Wiener-Korenberg technique can be applied to analyze the chaotic time series with surrogate data.
BER analysis of DS-UWB system employing a laplace distribution model
Mehbodniya, Abolfazl
2011-01-01
This letter takes a new approach to extract a closed-form expression for the bit error rate (BER) of direct-sequence ultra wideband (DS-UWB) system. In the analysis, the main signal is impaired by multi-user interference (MUI) and an external source of interference originated by simultanously transmitting multiband orthogonal frequency division multiplexing (MB-OFDM) systems which are located in the vicinity of the DS-UWB receiver. All the transmission channels are affected by Nakagami-m fading. A Laplacian distribution is considered for MUI to comply more with real statistical behaviors of this kind of interference. © IEICE 2011.
Logic-based models in systems biology: a predictive and parameter-free network analysis method†
Wynn, Michelle L.; Consul, Nikita; Merajver, Sofia D.
2012-01-01
Highly complex molecular networks, which play fundamental roles in almost all cellular processes, are known to be dysregulated in a number of diseases, most notably in cancer. As a consequence, there is a critical need to develop practical methodologies for constructing and analysing molecular networks at a systems level. Mathematical models built with continuous differential equations are an ideal methodology because they can provide a detailed picture of a network’s dynamics. To be predictive, however, differential equation models require that numerous parameters be known a priori and this information is almost never available. An alternative dynamical approach is the use of discrete logic-based models that can provide a good approximation of the qualitative behaviour of a biochemical system without the burden of a large parameter space. Despite their advantages, there remains significant resistance to the use of logic-based models in biology. Here, we address some common concerns and provide a brief tutorial on the use of logic-based models, which we motivate with biological examples. PMID:23072820
Popilski, Hen; Stepensky, David
2015-05-01
Solid tumors are characterized by complex morphology. Numerous factors relating to the composition of the cells and tumor stroma, vascularization and drainage of fluids affect the local microenvironment within a specific location inside the tumor. As a result, the intratumoral drug/drug delivery system (DDS) disposition following systemic or local administration is non-homogeneous and its complexity reflects the differences in the local microenvironment. Mathematical models can be used to analyze the intratumoral drug/DDS disposition and pharmacological effects and to assist in choice of optimal anticancer treatment strategies. The mathematical models that have been applied by different research groups to describe the intratumoral disposition of anticancer drugs/DDSs are summarized in this article. The properties of these models and of their suitability for prediction of the drug/DDS intratumoral disposition and pharmacological effects are reviewed. Currently available mathematical models appear to neglect some of the major factors that govern the drug/DDS intratumoral disposition, and apparently possess limited prediction capabilities. More sophisticated and detailed mathematical models and their extensive validation are needed for reliable prediction of different treatment scenarios and for optimization of drug treatment in the individual cancer patients.
Dynamical system analysis of a low-order tropical cyclone model
Directory of Open Access Journals (Sweden)
Daria Schönemann
2012-02-01
Full Text Available Tropical cyclone dynamics is investigated by means of a conceptual box model. The tropical cyclone (TC is divided into three regions, the eye, eyewall and ambient region. The model forms a low-order dynamical system of three ordinary differential equations. These are based on entropy budget equations comprising processes of surface enthalpy transfer, entropy advection, convection and radiative cooling. For tropical ocean parameter settings, the system possesses four non-trivial steady state solutions when the sea surface temperature (SST is above a critical value. Two steady states are unstable while the two remaining states are stable. Bifurcation diagrams provide an explanation why only finite-amplitude perturbations above a critical SST can transform into TCs. Besides SST, relative humidity of the ambient region forms an important model parameter. The surfaces that describe equilibria as a function of SST and relative humidity reveal a cusp-catastrophe where the two non-trivial equilibria split into four. Within the model regime of four equilibria, cyclogenesis becomes very unlikely due to the repelling and attracting effects of the two additional equilibria. The results are in qualitative agreement with observations and evince the relevance of the simple model approach to the dynamics of TC formation and its maximum potential intensity.
Razavi, S.; Gupta, H. V.
2014-12-01
Sensitivity analysis (SA) is an important paradigm in the context of Earth System model development and application, and provides a powerful tool that serves several essential functions in modelling practice, including 1) Uncertainty Apportionment - attribution of total uncertainty to different uncertainty sources, 2) Assessment of Similarity - diagnostic testing and evaluation of similarities between the functioning of the model and the real system, 3) Factor and Model Reduction - identification of non-influential factors and/or insensitive components of model structure, and 4) Factor Interdependence - investigation of the nature and strength of interactions between the factors, and the degree to which factors intensify, cancel, or compensate for the effects of each other. A variety of sensitivity analysis approaches have been proposed, each of which formally characterizes a different "intuitive" understanding of what is meant by the "sensitivity" of one or more model responses to its dependent factors (such as model parameters or forcings). These approaches are based on different philosophies and theoretical definitions of sensitivity, and range from simple local derivatives and one-factor-at-a-time procedures to rigorous variance-based (Sobol-type) approaches. In general, each approach focuses on, and identifies, different features and properties of the model response and may therefore lead to different (even conflicting) conclusions about the underlying sensitivity. This presentation revisits the theoretical basis for sensitivity analysis, and critically evaluates existing approaches so as to demonstrate their flaws and shortcomings. With this background, we discuss several important properties of response surfaces that are associated with the understanding and interpretation of sensitivity. Finally, a new approach towards global sensitivity assessment is developed that is consistent with important properties of Earth System model response surfaces.
Saloranta, Tuomo M; Andersen, Tom; Naes, Kristoffer
2006-01-01
Rate constant bioaccumulation models are applied to simulate the flow of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the coastal marine food web of Frierfjorden, a contaminated fjord in southern Norway. We apply two different ways to parameterize the rate constants in the model, global sensitivity analysis of the models using Extended Fourier Amplitude Sensitivity Test (Extended FAST) method, as well as results from general linear system theory, in order to obtain a more thorough insight to the system's behavior and to the flow pathways of the PCDD/Fs. We calibrate our models against observed body concentrations of PCDD/Fs in the food web of Frierfjorden. Differences between the predictions from the two models (using the same forcing and parameter values) are of the same magnitude as their individual deviations from observations, and the models can be said to perform about equally well in our case. Sensitivity analysis indicates that the success or failure of the models in predicting the PCDD/F concentrations in the food web organisms highly depends on the adequate estimation of the truly dissolved concentrations in water and sediment pore water. We discuss the pros and cons of such models in understanding and estimating the present and future concentrations and bioaccumulation of persistent organic pollutants in aquatic food webs.
Generic Model-Based Tailor-Made Design and Analysis of Biphasic Reaction Systems
DEFF Research Database (Denmark)
Anantpinijwatna, Amata
contribution of this thesis is the development of a systematic modelling framework for the biphasic reaction system. The developed framework consists of three modules describing phase equilibria, reactions and mass transfer, and material balances of such processes. Correlative and predictive thermodynamic......-elementary reaction rate laws. Extents of reaction are used to calculate the species material balances. The resulting mathematical model contains temperature dependent reaction rate parameters,equilibrium constants, and partition coefficients; where only the reaction rates are to be regressed to a minimum of time...
A review method for UML requirements analysis model employing system-side prototyping.
Ogata, Shinpei; Matsuura, Saeko
2013-12-01
User interface prototyping is an effective method for users to validate the requirements defined by analysts at an early stage of a software development. However, a user interface prototype system offers weak support for the analysts to verify the consistency of the specifications about internal aspects of a system such as business logic. As the result, the inconsistency causes a lot of rework costs because the inconsistency often makes the developers impossible to actualize the system based on the specifications. For verifying such consistency, functional prototyping is an effective method for the analysts, but it needs a lot of costs and more detailed specifications. In this paper, we propose a review method so that analysts can verify the consistency among several different kinds of diagrams in UML efficiently by employing system-side prototyping without the detailed model. The system-side prototype system does not have any functions to achieve business logic, but visualizes the results of the integration among the diagrams in UML as Web pages. The usefulness of our proposal was evaluated by applying our proposal into a development of Library Management System (LMS) for a laboratory. This development was conducted by a group. As the result, our proposal was useful for discovering the serious inconsistency caused by the misunderstanding among the members of the group.
Signal-to-noise performance analysis of streak tube imaging lidar systems. I. Cascaded model.
Yang, Hongru; Wu, Lei; Wang, Xiaopeng; Chen, Chao; Yu, Bing; Yang, Bin; Yuan, Liang; Wu, Lipeng; Xue, Zhanli; Li, Gaoping; Wu, Baoning
2012-12-20
Streak tube imaging lidar (STIL) is an active imaging system using a pulsed laser transmitter and a streak tube receiver to produce 3D range and intensity imagery. The STIL has recently attracted a great deal of interest and attention due to its advantages of wide azimuth field-of-view, high range and angle resolution, and high frame rate. This work investigates the signal-to-noise performance of STIL systems. A theoretical model for characterizing the signal-to-noise performance of the STIL system with an internal or external intensified streak tube receiver is presented, based on the linear cascaded systems theory of signal and noise propagation. The STIL system is decomposed into a series of cascaded imaging chains whose signal and noise transfer properties are described by the general (or the spatial-frequency dependent) noise factors (NFs). Expressions for the general NFs of the cascaded chains (or the main components) in the STIL system are derived. The work presented here is useful for the design and evaluation of STIL systems.
Energy Technology Data Exchange (ETDEWEB)
Georgopoulos, P.G.; Walia, A.; Roy, A.; Lioy, P.J. [Rutgers Univ. and Univ. of Medicine & Dentistry of New Jersey, Piscataway, NJ (United States)
1997-01-01
The conceptual and theoretical framework for a modular integrated Exposure and Dose Modeling and Analysis System (EDMAS) has been formulated, and its stepwise implementation and testing is currently in progress. This system aims to provide state-of-the art tools for performing integrated assessments of exposure and dose for individuals and populations. The integration of modeling components with each other as well as with available environmental, exposure, and toxicological databases in being accomplished with the use of computational tools that include interactive simulation environments, Geographical information Systems, and various data retrieval, management, statistical analysis, and visualization methods. This paper overviews the structure and modular nature of this integrated modeling system and focuses specifically on two of its components: (a) a hierarchy of physiologically based pharmacokinetic models (PBPKM), representing various levels of detail and sophistication, and (b) a family of microenvironmental models, that incorporate complex physical and chemical transformations. The deterministic implementation of these components is also presented here in two test applications: (i) a case study of benzene exposure indoors resulting from the volatilization of contaminated tap water and (ii) a case study of photochemical pollution infiltration indoors, in an office building environment. 77 refs., 6 figs., 2 tabs.
Modelling and stability analysis of emergent behavior of scalable swarm system
Institute of Scientific and Technical Information of China (English)
CHEN Shi-ming; FANG Hua-jing
2006-01-01
In this paper we propose a two-layer emergent model for scalable swarm system. The first layer describes the individual flocking behavior to the local goal position (the center of minimal circumcircle decided by the neighbors in the positive visual set of individuals) resulting from the individual motion to one or two farthest neighbors in its positive visual set; the second layer describes the emergent aggregating swarm behavior resulting from the individual motion to its local goal position. The scale of the swarm will not be limited because only local individual information is used for modelling in the two-layer topology. We study the stability properties of the swarm emergent behavior based on Lyapunov stability theory. Simulations showed that the swarm system can converge to goal regions while maintaining cohesiveness.
Analysis of a system modelling the motion of a piston in a viscous gas
Maity, Debayan; Takahashi, Takéo; Tucsnak, Marius
2016-09-01
We study a free boundary problem modelling the motion of a piston in a viscous gas. The gas-piston system fills a cylinder with fixed extremities, which possibly allow gas from the exterior to penetrate inside the cylinder. The gas is modeled by the 1D compressible Navier-Stokes system and the piston motion is described by the second Newton's law. We prove the existence and uniqueness of global in time strong solutions. The main novelty brought in by our results is that they include the case of nonhomogeneous boundary conditions which, as far as we know, have not been studied in this context. Moreover, even for homogeneous boundary conditions, our results require less regularity of the initial data than those obtained in previous works.
Cellier, Francois E.
1991-01-01
A comprehensive and systematic introduction is presented for the concepts associated with 'modeling', involving the transition from a physical system down to an abstract description of that system in the form of a set of differential and/or difference equations, and basing its treatment of modeling on the mathematics of dynamical systems. Attention is given to the principles of passive electrical circuit modeling, planar mechanical systems modeling, hierarchical modular modeling of continuous systems, and bond-graph modeling. Also discussed are modeling in equilibrium thermodynamics, population dynamics, and system dynamics, inductive reasoning, artificial neural networks, and automated model synthesis.
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.
2008-11-30
the project personnel. All publications are available on request. [Pl| R. Canetti , L. Cheung, D. Kaynar, M. Liskov, N". Lynch, O. Pereira, and R...March 2008. [P2] Ran Canetti , Ling Cheung, Dilsun Kaynar, Nancy Lynch, and Oliviei Pereira. Modeling Bounded Computation in Long-Lived Systems. CONCUR...pages 153-1G2, 2001. [4] R. Canetti , L. Cheung. D. Kaynar, M. Liskov, N. Lynch, O. Pereirt, and R. Segala. Analyz- ing Security Protocol Using Thne
Analysis of Demand Control Policies using an Agent-based Multi-layer Power System Model
Kühnlenz, Florian; Nardelli, Pedro H. J.; Alves, Hirley
2016-01-01
This paper studies how the communication network affects the power utilization and fairness in a simplified power system model, composed by three coupled layers: physical, communication and regulatory. Using an agent-based approach, we build a scenario where individuals may cooperate (by removing a load) or not (by keeping their loads or adding one more). The agent decision reflects its desire of maximizing the delivered power based on its internal state, its global state perception, a random...
Incidence analysis of higher education financing system in Spain using a behavioural model.
Laura de Pablos Escobar; María Gil Izquierdo
2008-01-01
The aim of this paper is to analyse the distributive effects of some potential reforms in the Higher Education Financing System using a behavioural model, for the Spanish case in the new millennium. Specifically, improvements in income distribution due to some reforms in the educational policy are evaluated, based on international trends and “experts” recommendations. These measures refer to changes in quantity and coverage of grants, tuition fees and public subsidies per student in public un...
Stability analysis of multi-compartment models for cell production systems.
Nakata, Yukihiko; Getto, Philipp; Marciniak-Czochra, Anna; Alarcón, Tomás
2012-01-01
We study two- and three-compartment models of a hierarchical cell production system with cell division regulated by the level of mature cells. We investigate the structure of equilibria with respect to parameters as well as local stability properties for the equilibria. To interpret the results we adapt the concept of reproduction numbers, which is well known in ecology, to stem cell population dynamics. In the two-compartment model, the positive equilibrium is stable wherever it exists. In the three-compartment model, we find that the intermediate stage of differentiation is responsible for the emergence of an instability region in the parameter plane. Moreover, we prove that this region shrinks as the mortality rate for mature cells increases and discuss this result.
Mayaud, C; Wagner, T; Benischke, R; Birk, S
2014-04-16
The Lurbach karst system (Styria, Austria) is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists (allogenic recharge). Detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub-catchments to the other is activated if the discharge of the main spring exceeds a certain threshold. Time series analysis (autocorrelation and cross-correlation) was applied to examine to what extent the various available methods support the identification of the transient inter-catchment flow observed in this binary karst system. As inter-catchment flow is found to be intermittent, the evaluation was focused on single events. In order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using MODFLOW. The groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied. Using the wetting capability package of MODFLOW, the model simulated an overflow similar to what has been observed during the tracer experiment. Various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis. In addition, geometric and hydraulic properties of the karst system were varied in several model scenarios. This approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis. Comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found. For instance, the cross-correlograms show similar patterns with respect to time lags and maximum cross-correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model. The comparable behaviors of the real and the
Mayaud, C.; Wagner, T.; Benischke, R.; Birk, S.
2014-04-01
The Lurbach karst system (Styria, Austria) is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists (allogenic recharge). Detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub-catchments to the other is activated if the discharge of the main spring exceeds a certain threshold. Time series analysis (autocorrelation and cross-correlation) was applied to examine to what extent the various available methods support the identification of the transient inter-catchment flow observed in this binary karst system. As inter-catchment flow is found to be intermittent, the evaluation was focused on single events. In order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using MODFLOW. The groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied. Using the wetting capability package of MODFLOW, the model simulated an overflow similar to what has been observed during the tracer experiment. Various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis. In addition, geometric and hydraulic properties of the karst system were varied in several model scenarios. This approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis. Comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found. For instance, the cross-correlograms show similar patterns with respect to time lags and maximum cross-correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model. The comparable behaviors of the real and the
Mayaud, C.; Wagner, T.; Benischke, R.; Birk, S.
2014-01-01
Summary The Lurbach karst system (Styria, Austria) is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists (allogenic recharge). Detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub-catchments to the other is activated if the discharge of the main spring exceeds a certain threshold. Time series analysis (autocorrelation and cross-correlation) was applied to examine to what extent the various available methods support the identification of the transient inter-catchment flow observed in this binary karst system. As inter-catchment flow is found to be intermittent, the evaluation was focused on single events. In order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using MODFLOW. The groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied. Using the wetting capability package of MODFLOW, the model simulated an overflow similar to what has been observed during the tracer experiment. Various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis. In addition, geometric and hydraulic properties of the karst system were varied in several model scenarios. This approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis. Comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found. For instance, the cross-correlograms show similar patterns with respect to time lags and maximum cross-correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model. The comparable behaviors of the real and
MOSES – A modelling tool for the analysis of scenarios of the European electricity supply system
Directory of Open Access Journals (Sweden)
Agert C.
2012-10-01
Full Text Available Recent studies have shown that a transition of the current power supply system in Europe to a system almost entirely based on fluctuating Renewable Energy Sources (RES by mid-century is possible. However, most of these scenarios require a significant amount of back-up power capacities to ensure the security of electricity supply. This would imply high additional investments and operating costs. Hence, alternative options should be investigated first. Here we present a first outlook of our simulation model MOSES which will be able to analyse different target states of the European electricity system in 2050. In this model long-term meteorological data series are used to optimise the capacity mix of RES in Europe. One of the main elements of our tool is a simplified electricity network. In addition, alternative options for reduction of additional back-up power like the expansion of the transmission grid, the use of demand-side management and/or the installation of over-capacities will be implemented. The results will be used to provide scientifically proven recommendations to policy makers for a reliable energy supply system in Europe based on Renewable Energy Sources.
Simulation modeling and analysis of a complex system of a thermal power plant
Directory of Open Access Journals (Sweden)
Sorabh Gupta
2009-09-01
Full Text Available The present paper deals with the opportunities for the modeling of flue gas and air system of a thermal power plant by making the performance evaluation using probabilistic approach. The present system of thermal plant under study consists of four subsystems with three possible states: full working, reduced capacity working and failed. Failure and repair rates for all the subsystems are assumed to be constant. Formulation of the problem is carried out using Markov Birth-Death process using probabilistic approach and a transition diagram represents the operational behavior of the system. Interrelationship among the full working and reduced working has been developed. A probabilistic model has been developed, considering some assumptions. Data in feasible range are selected from a survey of thermal plant and the effect of each subsystem on the system availability is tabulated in the form of availability matrices, which provides various performance/availability levels for different combinations of failure and repair rates of all subsystems. Based upon various availability values obtained in availability matrices and graphs of failure/repair rates of different subsystems, performance and optimum values of failure/repair rates for maximum availability, of each subsystem is analyzed and then maintenance priorities are decided for all subsystems.
Allen, E. R.; Stephens, J. C.; Kruger, C.; Leung, F. T.
2011-12-01
Engaging stakeholders in the development of regional earth systems models has potential to improve model accuracy and enhance model relevance for decision makers. BioEarth is one earth systems modeling project currently under development aimed at investigating how climate and human-induced changes impact environmental nitrogen and carbon cycling. One proposed application of this model is to predict impacts on natural resource management in the Pacific Northwest to inform decision-making by stakeholders in the forestry and agriculture sectors. Integrating input from natural resource managers and other stakeholders into the model development process, therefore, is critical. However, many model developers have limited experience in engaging stakeholders throughout model development processes. Understanding researchers' perceptions of the potential value and challenges of stakeholder engagement in model development at the early phase of the project provides general insights related to science communication as well as project-specific insights. For BioEarth, findings about project scientists' perspectives may inform the design of information exchange mechanisms between researchers and stakeholders. To assess researchers' perceptions of the relevance of the model to decision-making and understand researchers' previous experiences, expectations and concerns regarding stakeholder input and interaction we conducted a semi-formal interview and a quantitative questionnaire with each of the project's 18 principal investigators. Interview transcripts were coded and interpreted following a thematic content analysis approach. We expect to find a range of perceptions among BioEarth researchers regarding the kind of involvement and degree of influence that stakeholders may have in the model development process. We also expect a range of attitudes and approaches toward participatory research processes. In addition to improving the effectiveness of stakeholder engagement in the
Connecting Requirements to Architecture and Analysis via Model-Based Systems Engineering
Cole, Bjorn F.; Jenkins, J. Steven
2015-01-01
In traditional systems engineering practice, architecture, concept development, and requirements development are related but still separate activities. Concepts for operation, key technical approaches, and related proofs of concept are developed. These inform the formulation of an architecture at multiple levels, starting with the overall system composition and functionality and progressing into more detail. As this formulation is done, a parallel activity develops a set of English statements that constrain solutions. These requirements are often called "shall statements" since they are formulated to use "shall." The separation of requirements from design is exacerbated by well-meaning tools like the Dynamic Object-Oriented Requirements System (DOORS) that remained separated from engineering design tools. With the Europa Clipper project, efforts are being taken to change the requirements development approach from a separate activity to one intimately embedded in formulation effort. This paper presents a modeling approach and related tooling to generate English requirement statements from constraints embedded in architecture definition.
Modeling and Power Flow Analysis for Herringbone Gears Power Dual-Branching Transmission System
Yang, Xiaofang; Zhu, Yanxiang; Fang, Zongde; Gu, Jiangong
Based on power dual-branching transmission system of herringbone gears, the mechanical structural model was established. This study represented the simplified algorithm to obtain its power flow situations through formulating the deformation compatibility condition for the linear relationship between the torque and transverse deformation of tooth surface and the torque equilibrium condition. Besides, the effects on the power flow of system were calculated under all kinds of the installation error and processing error of gear pairs. Finally, the power flow situations of dual branches were solved via Programming. A numerical example that illustrated the developed theory was provided. The research results can be applied to analyze the actual application of herringbone gears power split-path transmission system.
Connecting Requirements to Architecture and Analysis via Model-Based Systems Engineering
Cole, Bjorn F.; Jenkins, J. Steven
2015-01-01
In traditional systems engineering practice, architecture, concept development, and requirements development are related but still separate activities. Concepts for operation, key technical approaches, and related proofs of concept are developed. These inform the formulation of an architecture at multiple levels, starting with the overall system composition and functionality and progressing into more detail. As this formulation is done, a parallel activity develops a set of English statements that constrain solutions. These requirements are often called "shall statements" since they are formulated to use "shall." The separation of requirements from design is exacerbated by well-meaning tools like the Dynamic Object-Oriented Requirements System (DOORS) that remained separated from engineering design tools. With the Europa Clipper project, efforts are being taken to change the requirements development approach from a separate activity to one intimately embedded in formulation effort. This paper presents a modeling approach and related tooling to generate English requirement statements from constraints embedded in architecture definition.
Validation of systems biology models
Hasdemir, D.
2015-01-01
The paradigm shift from qualitative to quantitative analysis of biological systems brought a substantial number of modeling approaches to the stage of molecular biology research. These include but certainly are not limited to nonlinear kinetic models, static network models and models obtained by the
Energy Technology Data Exchange (ETDEWEB)
Suh, Kune Yull; Yoon, Sang Hyuk; Noh, Sang Woo; Lee, Il Suk [Seoul National University, Seoul (Korea)
2002-03-01
This study is concerned with developing a multidimensional flow model required for the system analysis code MARS to more mechanistically simulate a variety of thermal hydraulic phenomena in the nuclear stem supply system. The capability of the MARS code as a thermal hydraulic analysis tool for optimized system design can be expanded by improving the current calculational methods and adding new models. In this study the relevant literature was surveyed on the multidimensional flow models that may potentially be applied to the multidimensional analysis code. Research items were critically reviewed and suggested to better predict the multidimensional thermal hydraulic behavior and to identify test requirements. A small-scale preliminary test was performed in the downcomer formed by two vertical plates to analyze multidimensional flow pattern in a simple geometry. The experimental result may be applied to the code for analysis of the fluid impingement to the reactor downcomer wall. Also, data were collected to find out the controlling parameters for the one-dimensional and multidimensional flow behavior. 22 refs., 40 figs., 7 tabs. (Author)
Wu, Guang; Dong, Zuomin
2017-09-01
Hybrid electric vehicles are widely accepted as a promising short to mid-term technical solution due to noticeably improved efficiency and lower emissions at competitive costs. In recent years, various hybrid powertrain systems were proposed and implemented based on different types of conventional transmission. Power-split system, including Toyota Hybrid System and Ford Hybrid System, are well-known examples. However, their relatively low torque capacity, and the drive of alternative and more advanced designs encouraged other innovative hybrid system designs. In this work, a new type of hybrid powertrain system based hybridized automated manual transmission (HAMT) is proposed. By using the concept of torque gap filler (TGF), this new hybrid powertrain type has the potential to overcome issue of torque gap during gearshift. The HAMT design (patent pending) is described in details, from gear layout and design of gear ratios (EV mode and HEV mode) to torque paths at different gears. As an analytical tool, mutli-body model of vehicle equipped with this HAMT was built to analyze powertrain dynamics at various steady and transient modes. A gearshift was decomposed and analyzed based basic modes. Furthermore, a Simulink-SimDriveline hybrid vehicle model was built for the new transmission, driveline and vehicle modular. Control strategy has also been built to harmonically coordinate different powertrain components to realize TGF function. A vehicle launch simulation test has been completed under 30% of accelerator pedal position to reveal details during gearshift. Simulation results showed that this HAMT can eliminate most torque gap that has been persistent issue of traditional AMT, improving both drivability and performance. This work demonstrated a new type of transmission that features high torque capacity, high efficiency and improved drivability.
Schafer, R. M.; Sain, M. K.
1980-01-01
The paper presents the CARDIAD (complex acceptability region for diagonal dominance) method for achieving the diagonal dominance condition in the inverse Nyquist array approach to the analysis and design of multivariable systems in the frequency domain. A design example is given for a sixth order, 4-input, 4-output model of a turbofan engine.
Dynamic modelling of a one-stage spur gear system and vibration-based tooth crack detection analysis
Mohammed, Omar D.; Rantatalo, Matti; Aidanpää, Jan-Olov
2015-03-01
For the purpose of simulation and vibration-based condition monitoring of a geared system, it is important to model the system with an appropriate number of degrees of freedom (DOF). In earlier papers several models were suggested and it is therefore of interest to evaluate their limitations. In the present study a 12 DOF gear dynamic model including a gyroscopic effect was developed and the equations of motions were derived. A one-stage reduction gear was modelled using three different dynamic models (with 6, 8 and 8 reduced to 6 DOF), as well as the developed model (with 12 DOF), which is referred as the fourth model in this paper. The time-varying mesh stiffness was calculated, and dynamic simulation was then performed for different crack sizes. Time domain scalar indicators (the RMS, kurtosis and the crest factor) were applied for fault detection analysis. The results of the first model show a clearly visible difference from those of the other studied models, which were made more realistic by including two more DOF to describe the motor and load. Both the symmetric and the asymmetric disc cases were studied using the fourth model. In the case of disc symmetry, the results of the obtained response are close to those obtained from both the second and third models. Furthermore, the second model showed a slight influence from inter-tooth friction, and therefore the third model is adequate for simulating the pinion's y-displacement in the case of the symmetric disc. In the case of the asymmetric disc, the results deviate from those obtained in the symmetric case. Therefore, for simulating the pinion's y-displacement, the fourth model can be considered for more accurate modelling in the case of the asymmetric disc.
Raffaeli, Leah R.
Techno-economic and systems studies on microalgal growth scenarios to date are abbreviated and missing a number of important variables. By including these variables in a detailed model integrating biology, chemistry, engineering, and financial aspects, a more defined systems analysis is possible. Through optimizing the model productivity based on the resulting net profit, the system analysis results in a more accurate assessment of environmental and economic sustainability of specific algal growth scenarios. Photobioreactor algal growth scenario optimization in the system model has resulted in realistic engineering design requirements based on algal growth requirements and fluid dynamics analysis. Results show feasibility for photobioreactor growth scenarios to be economically sustainable when co-products are included, but definite technological advancements and productivity improvements must be made. The main factors inhibiting a cost effective photobioreactor growth scenario are culture density, temperature, and lighting distribution for solar illuminated photobioreactors, and lighting cost for artificially illuminated photobioreactors. Open pond algal growth scenarios do not show any prospect of economic or environmental sustainability with current technology due to the large amount of surface area required, inefficient water use, and low culture density. All algal growth scenarios are inferior to petro-diesel regarding energy inputs, carbon emissions, and environmental sustainability. No algal growth scenarios analyzed in this study meet the U.S. requirement of biofuel emitting at least 20% less carbon emissions than diesel from crude oil.
Model-based biofuels system analysis:a review%生物燃料系统分析模型
Institute of Scientific and Technical Information of China (English)
常世彦; 张希良; 赵丽丽; 欧训民
2011-01-01
定量化系统分析模型是生物燃料潜力预测、影响分析及制定技术路线图和政策目标的重要工具.生物燃料供应链涉及很多行业,需要进行基于农(林)业、能源、经济和环境等多学科领域的综合分析.以下从生物燃料系统分析所需解决的问题出发,梳理了国内外生物燃料系统分析的一般方法,重点对农(林)业系统模型、能源系统模型、综合评价模型,微观成本、能耗和排放分析模型以及生物燃料专项宏观分析模型的主要优缺点和适用性进行了分析,给出了相应的应用实例,并强调根据特定的研究问题,选择具有不同适用性的模型和研究路线.有助于研究人员和政策制定者更好地了解生物燃料系统分析方法,也为我国学术研究机构建立生物燃料分析模型提供了参考.%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.
Hamlet, A. F.; Chiu, C. M.; Sharma, A.; Byun, K.; Hanson, Z.
2016-12-01
Physically based hydrologic modeling of surface and groundwater resources that can be flexibly and efficiently applied to support water resources policy/planning/management decisions at a wide range of spatial and temporal scales are greatly needed in the Midwest, where stakeholder access to such tools is currently a fundamental barrier to basic climate change assessment and adaptation efforts, and also the co-production of useful products to support detailed decision making. Based on earlier pilot studies in the Pacific Northwest Region, we are currently assembling a suite of end-to-end tools and resources to support various kinds of water resources planning and management applications across the region. One of the key aspects of these integrated tools is that the user community can access gridded products at any point along the end-to-end chain of models, looking backwards in time about 100 years (1915-2015), and forwards in time about 85 years using CMIP5 climate model projections. The integrated model is composed of historical and projected future meteorological data based on station observations and statistical and dynamically downscaled climate model output respectively. These gridded meteorological data sets serve as forcing data for the macro-scale VIC hydrologic model implemented over the Midwest at 1/16 degree resolution. High-resolution climate model (4km WRF) output provides inputs for the analyses of urban impacts, hydrologic extremes, agricultural impacts, and impacts to the Great Lakes. Groundwater recharge estimated by the surface water model provides input data for fine-scale and macro-scale groundwater models needed for specific applications. To highlight the multi-scale use of the integrated models in support of co-production of scientific information for decision making, we briefly describe three current case studies addressing different spatial scales of analysis: 1) Effects of climate change on the water balance of the Great Lakes, 2) Future
Analysis of a Stochastic Chemical System Close to a SNIPER Bifurcation of Its Mean-Field Model
Erban, Radek
2009-01-01
A framework for the analysis of stochastic models of chemical systems for which the deterministic mean-field description is undergoing a saddle-node infinite period (SNIPER) bifurcation is presented. Such a bifurcation occurs, for example, in the modeling of cell-cycle regulation. It is shown that the stochastic system possesses oscillatory solutions even for parameter values for which the mean-field model does not oscillate. The dependence of the mean period of these oscillations on the parameters of the model (kinetic rate constants) and the size of the system (number of molecules present) are studied. Our approach is based on the chemical Fokker-Planck equation. To gain some insight into the advantages and disadvantages of the method, a simple one-dimensional chemical switch is first analyzed, and then the chemical SNIPER problem is studied in detail. First, results obtained by solving the Fokker-Planck equation numerically are presented. Then an asymptotic analysis of the Fokker-Planck equation is used to derive explicit formulae for the period of oscillation as a function of the rate constants and as a function of the system size. © 2009 Society for Industrial and Applied Mathematics.
Polverino, Pierpaolo; Frisk, Erik; Jung, Daniel; Krysander, Mattias; Pianese, Cesare
2017-07-01
The present paper proposes an advanced approach for Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems fault detection and isolation through a model-based diagnostic algorithm. The considered algorithm is developed upon a lumped parameter model simulating a whole PEMFC system oriented towards automotive applications. This model is inspired by other models available in the literature, with further attention to stack thermal dynamics and water management. The developed model is analysed by means of Structural Analysis, to identify the correlations among involved physical variables, defined equations and a set of faults which may occur in the system (related to both auxiliary components malfunctions and stack degradation phenomena). Residual generators are designed by means of Causal Computation analysis and the maximum theoretical fault isolability, achievable with a minimal number of installed sensors, is investigated. The achieved results proved the capability of the algorithm to theoretically detect and isolate almost all faults with the only use of stack voltage and temperature sensors, with significant advantages from an industrial point of view. The effective fault isolability is proved through fault simulations at a specific fault magnitude with an advanced residual evaluation technique, to consider quantitative residual deviations from normal conditions and achieve univocal fault isolation.
ANALYSIS OF THE POSSIBILITIES OF USING LOW-COST SCANNING SYSTEM IN 3D MODELING
Directory of Open Access Journals (Sweden)
M. Kedzierski
2016-06-01
Full Text Available The laser scanning technique is still a very popular and fast growing method of obtaining information on modeling 3D objects. The use of low-cost miniature scanners creates new opportunities for small objects of 3D modeling based on point clouds acquired from the scan. The same, the development of accuracy and methods of automatic processing of this data type is noticeable. The article presents methods of collecting raw datasets in the form of a point-cloud using a low-cost ground-based laser scanner FabScan. As part of the research work 3D scanner from an open source FabLab project was constructed. In addition, the results for the analysis of the geometry of the point clouds obtained by using a low-cost laser scanner were presented. Also, some analysis of collecting data of different structures (made of various materials such as: glass, wood, paper, gum, plastic, plaster, ceramics, stoneware clay etc. and of different shapes: oval and similar to oval and prism shaped have been done. The article presents two methods used for analysis: the first one - visual (general comparison between the 3D model and the real object and the second one - comparative method (comparison between measurements on models and scanned objects using the mean error of a single sample of observations. The analysis showed, that the low-budget ground-based laser scanner FabScan has difficulties with collecting data of non-oval objects. Items built of glass painted black also caused problems for the scanner. In addition, the more details scanned object contains, the lower the accuracy of the collected point-cloud is. Nevertheless, the accuracy of collected data (using oval-straight shaped objects is satisfactory. The accuracy, in this case, fluctuates between ± 0,4 mm and ± 1,0 mm whereas when using more detailed objects or a rectangular shaped prism the accuracy is much more lower, between 2,9 mm and ± 9,0 mm. Finally, the publication presents the possibility (for the
Analysis of the Possibilities of Using Low-Cost Scanning System in 3d Modeling
Kedzierski, M.; Wierzbickia, D.; Fryskowska, A.; Chlebowska, B.
2016-06-01
The laser scanning technique is still a very popular and fast growing method of obtaining information on modeling 3D objects. The use of low-cost miniature scanners creates new opportunities for small objects of 3D modeling based on point clouds acquired from the scan. The same, the development of accuracy and methods of automatic processing of this data type is noticeable. The article presents methods of collecting raw datasets in the form of a point-cloud using a low-cost ground-based laser scanner FabScan. As part of the research work 3D scanner from an open source FabLab project was constructed. In addition, the results for the analysis of the geometry of the point clouds obtained by using a low-cost laser scanner were presented. Also, some analysis of collecting data of different structures (made of various materials such as: glass, wood, paper, gum, plastic, plaster, ceramics, stoneware clay etc. and of different shapes: oval and similar to oval and prism shaped) have been done. The article presents two methods used for analysis: the first one - visual (general comparison between the 3D model and the real object) and the second one - comparative method (comparison between measurements on models and scanned objects using the mean error of a single sample of observations). The analysis showed, that the low-budget ground-based laser scanner FabScan has difficulties with collecting data of non-oval objects. Items built of glass painted black also caused problems for the scanner. In addition, the more details scanned object contains, the lower the accuracy of the collected point-cloud is. Nevertheless, the accuracy of collected data (using oval-straight shaped objects) is satisfactory. The accuracy, in this case, fluctuates between ± 0,4 mm and ± 1,0 mm whereas when using more detailed objects or a rectangular shaped prism the accuracy is much more lower, between 2,9 mm and ± 9,0 mm. Finally, the publication presents the possibility (for the future expansion of
Model Checking as Static Analysis
DEFF Research Database (Denmark)
Zhang, Fuyuan
Both model checking and static analysis are prominent approaches to detecting software errors. Model Checking is a successful formal method for verifying properties specified in temporal logics with respect to transition systems. Static analysis is also a powerful method for validating program...... properties which can predict safe approximations to program behaviors. In this thesis, we have developed several static analysis based techniques to solve model checking problems, aiming at showing the link between static analysis and model checking. We focus on logical approaches to static analysis......-calculus can be encoded as the intended model of SFP. Our research results have strengthened the link between model checking and static analysis. This provides a theoretical foundation for developing a unied tool for both model checking and static analysis techniques....
Fu, Jie; Li, Peidong; Wang, Yuan; Liao, Guanyao; Yu, Miao
2016-03-01
This paper addresses the problem of micro-vibration control of a precision vibration isolation system with a magnetorheological elastomer (MRE) isolator and fuzzy control strategy. Firstly, a polyurethane matrix MRE isolator working in the shear-compression mixed mode is introduced. The dynamic characteristic is experimentally tested, and the range of the frequency shift and the model parameters of the MRE isolator are obtained from experimental results. Secondly, a new semi-active control law is proposed, which uses isolation structure displacement and relative displacement between the isolation structure and base as the inputs. Considering the nonlinearity of the MRE isolator and the excitation uncertainty of an isolation system, the designed semi-active fuzzy logic controller (FLC) is independent of a system model and is robust. Finally, the numerical simulations and experiments are conducted to evaluate the performance of the FLC with single-frequency and multiple-frequency excitation, respectively, and the experimental results show that the acceleration transmissibility is reduced by 54.04% at most, which verifies the effectiveness of the designed semi-active FLC. Moreover, the advantages of the approach are demonstrated in comparison to the passive control and ON-OFF control.
Modeling and analysis of airlift system operating in three-phase flow
Hu, Dong; Kang, Yong; Tang, Chuan-lin; Wang, Xiao-chuan
2015-03-01
Based on the momentum theorem, the fluid governing equation in a lifting pipe is proposed by use of the method combining theoretical analysis with empirical correlations related to the previous research, and the performance of an airlift pump can be clearly characterized by the triangular relationship among the volumetric flux of air, water and solid particles, which are obtained respectively by using numerical calculation. The meso-scale river sand is used as tested particles to examine the theoretical model. Results of the model are compared with the data in three-phase flow obtained prior to the development of the present model, by an independent experimental team that used the physical conditions of the present approach. The analytical error can be controlled within 12% for predicting the volumetric flux of water and is smaller than that (±16%) of transporting solid particles in three-phase flow. The experimental results and computations are in good agreement for air-water two-phase flow within a margin of ±8%. Reasonable agreement justifies the use of the present model for engineering design purposes.
Modeling and Analysis of Airlift System Operating in Three-Phase Flow
Institute of Scientific and Technical Information of China (English)
胡东; 康勇; 唐川林; 王晓川
2015-01-01
Based on themomentum theorem, the fluid governing equation in a lifting pipe is proposed by use of the method combining theoretical analysis with empirical correlations related to the previous research, and the performance of an airlift pump can be clearly characterized by the triangular relationship among the volumetric flux of air, water and solid particles, which are obtained respectively by using numerical calculation. The meso-scale river sand is used as tested particles to examine the theoretical model. Results of the model are compared with the data in three-phase flow obtained prior to the development of the present model, by an independent experimental team that used the physical conditions of the present approach. The analytical error can be controlled within 12% for predicting the volumetric flux of water and is smaller than that (±16%) of transporting solid particles in three-phase flow.The experimental results and computations are in good agreement for air-water two-phase flow within a margin of±8%. Reasonable agreement justifies the use of the present model for engineering design purposes.
de Santa-Eulalia, Luis Antonio; Frayret, Jean-Marc
2011-01-01
Despite the extensive use of the agent technology in the Supply Chain Management field, its integration with Advanced Planning and Scheduling (APS) tools still represents a promising field with several open research questions. Specifically, the literature falls short in providing an integrated framework to analyze, specify, design and implement simulation experiments covering the whole simulation cycle. Thus, this paper proposes an agent-based strategy to convert the 'analysis' models into 'specification' and 'design' models combining two existing methodologies proposed in the literature. The first one is a recent and unique approach dedicated to the 'analysis' of agent-based APS systems. The second one is a well-established methodological framework to 'specify' and 'design' agent-based supply chain systems. The proposed conversion strategy is original and is the first one allowing simulation analysts to integrate the whole simulation development process in the domain of distributed APS.
Object-oriented analysis and design for information systems Modeling with UML, OCL, IFML
Wazlawick, Raul Sidnei
2014-01-01
Object-Oriented Analysis and Design for Information Systems clearly explains real object-oriented programming in practice. Expert author Raul Sidnei Wazlawick explains concepts such as object responsibility, visibility and the real need for delegation in detail. The object-oriented code generated by using these concepts in a systematic way is concise, organized and reusable. The patterns and solutions presented in this book are based in research and industrial applications. You will come away with clarity regarding processes and use cases and a clear understand of how to expand a use case.
Liu, Shibing; Yang, Bingen
2015-08-01
Flexible multistage rotating systems that are supported or guided by long water-lubricated rubber bearings (WLRBs) have a variety of engineering applications. Vibration analysis of this type of machinery for performance and duality requires accurate modeling of WLRBs and related rotor-bearing assemblies. This work presents a new model of WLRBs, with attention given to the determination of bearing dynamic coefficients. Due to its large length-to-diameter ratio, a WLRB cannot be described by conventional pointwise bearing models with good fidelity. The bearing model proposed in this paper considers spatially distributed bearing forces. For the first time in the literature, the current study addresses the issue of mixed lubrication in the operation of WLRBs, which involves interactions of shaft vibration, elastic deformation of rubber material and fluid film pressure, and validates the WLRB model in experiments. Additionally, with the new bearing model, vibration analysis of WLRB-supported flexible multistage rotating systems is performed through use of a distributed transfer function method, which delivers accurate and closed-form analytical solutions of steady-state responses without discretization.
DEFF Research Database (Denmark)
Mustaffa, Azizul Azri
the molecular fragmentation that relates properties which is the molecular interactions with the molecular structures. One well known and established group-contribution method is the UNIFAC model, used to predict liquid phase activity coefficients for mixtures. The needed values of the group interaction...... parameters (GIPs) are obtained by fitting phase equilibrium data. There are, however many gaps in the UNIFAC parameter table due to lack of data. Alternative to performing measurements, which may not be feasible, values of the missing GIPs, can be predicted through the GCPlus approach. The predicted values...... further developed by including chlorinated and sulfurated VLE systems. Finally, in Chapter 7, the developed Original UNIFAC-CI (VLE/SLE) model has been highlighted in selected case studies involving the design of a working solution for hydrogen peroxide production and solubility investigation...
De Biase, Cecilia; Carminati, Andrea; Oswald, Sascha E; Thullner, Martin
2013-11-01
Vertical flow systems filled with porous medium have been shown to efficiently remove volatile organic contaminants (VOCs) from contaminated groundwater. To apply this semi-natural remediation strategy it is however necessary to distinguish between removal due to biodegradation and due to volatile losses to the atmosphere. Especially for (potentially) toxic VOCs, the latter needs to be minimized to limit atmospheric emissions. In this study, numerical simulation was used to investigate quantitatively the removal of volatile organic compounds in two pilot-scale water treatment systems: an unplanted vertical flow filter and a planted one, which could also be called a vertical flow constructed wetland, both used for the treatment of contaminated groundwater. These systems were intermittently loaded with contaminated water containing benzene and MTBE as main VOCs. The highly dynamic but permanently unsaturated conditions in the porous medium facilitated aerobic biodegradation but could lead to volatile emissions of the contaminants. Experimental data from porous material analyses, flow rate measurements, solute tracer and gas tracer test, as well as contaminant concentration measurements at the boundaries of the systems were used to constrain a numerical reactive transport modeling approach. Numerical simulations considered unsaturated water flow, transport of species in the aqueous and the gas phase as well as aerobic degradation processes, which made it possible to quantify the rates of biodegradation and volatile emissions and calculating their contribution to total contaminant removal. A range of degradation rates was determined using experimental results of both systems under two operation modes and validated by field data obtained at different operation modes applied to the filters. For both filters, simulations and experimental data point to high biodegradation rates, if the flow filters have had time to build up their removal capacity. For this case volatile
Energy Technology Data Exchange (ETDEWEB)
Brasser, R.; Ida, S. [Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550 (Japan); Matsumura, S. [School of Science and Engineering, Division of Physics, Fulton Building, University of Dundee, Dundee DD1 4HN (United Kingdom); Mojzsis, S. J. [Collaborative for Research in Origins (CRiO), Department of Geological Sciences, University of Colorado, UCB 399, 2200 Colorado Avenue, Boulder, Colorado 80309-0399 (United States); Werner, S. C. [The Centre for Earth Evolution and Dynamics, University of Oslo, Sem Saelandsvei 24, NO-0371 Oslo (Norway)
2016-04-20
The Grand Tack model of terrestrial planet formation has emerged in recent years as the premier scenario used to account for several observed features of the inner solar system. It relies on the early migration of the giant planets to gravitationally sculpt and mix the planetesimal disk down to ∼1 au, after which the terrestrial planets accrete from material remaining in a narrow circumsolar annulus. Here, we investigate how the model fares under a range of initial conditions and migration course-change (“tack”) locations. We run a large number of N-body simulations with tack locations of 1.5 and 2 au and test initial conditions using equal-mass planetary embryos and a semi-analytical approach to oligarchic growth. We make use of a recent model of the protosolar disk that takes into account viscous heating, includes the full effect of type 1 migration, and employs a realistic mass–radius relation for the growing terrestrial planets. Our results show that the canonical tack location of Jupiter at 1.5 au is inconsistent with the most massive planet residing at 1 au at greater than 95% confidence. This favors a tack farther out at 2 au for the disk model and parameters employed. Of the different initial conditions, we find that the oligarchic case is capable of statistically reproducing the orbital architecture and mass distribution of the terrestrial planets, while the equal-mass embryo case is not.
Development of a natural gas systems analysis model (GSAM). Annual report, July 1996--July 1997
Energy Technology Data Exchange (ETDEWEB)
NONE
1997-12-31
The objective of GSAM development is to create a comprehensive, non-proprietary, microcomputer model of the North American natural gas system. GSAM explicitly evaluates the key components of the system, including the resource base, exploration and development practices, extraction technology performance and costs, project economics, transportation costs and restrictions, storage, and end-use. The primary focus is the detailed characterization of the resource base at the reservoir and subreservoir level. This disaggregation allows direct evaluation of alternative extraction technologies based on discretely estimated, individual well productivity, required investments, and associated operating costs. GSAM`s design allows users to evaluate complex interactions of current and alternative future technology and policy initiatives as they directly impact the gas market. GSAM development has been ongoing for the past five years. Key activities completed during the past year are described.
Campolina, Daniel de A. M.; Lima, Claubia P. B.; Veloso, Maria Auxiliadora F.
2014-06-01
For all the physical components that comprise a nuclear system there is an uncertainty. Assessing the impact of uncertainties in the simulation of fissionable material systems is essential for a best estimate calculation that has been replacing the conservative model calculations as the computational power increases. The propagation of uncertainty in a simulation using a Monte Carlo code by sampling the input parameters is recent because of the huge computational effort required. In this work a sample space of MCNPX calculations was used to propagate the uncertainty. The sample size was optimized using the Wilks formula for a 95th percentile and a two-sided statistical tolerance interval of 95%. Uncertainties in input parameters of the reactor considered included geometry dimensions and densities. It was showed the capacity of the sampling-based method for burnup when the calculations sample size is optimized and many parameter uncertainties are investigated together, in the same input.
National Research Council Canada - National Science Library
Downer, Charles
2003-01-01
This document is a primer for use of the Watershed Modeling System (WMS) interface with the physically based, distributed-parameter hydrologic model Gridded Surface Subsurface Hydrologic Analysis (GSSHA...
Directory of Open Access Journals (Sweden)
Jayr Figueiredo de Oliveira
2013-10-01
Full Text Available This article proposes an information technology model to evaluate fleet management failure. Qualitative research done by a case study within an Interstate Transport company in a São Paulo State proposed to establish a relationship between computer tools and valid trustworthy information needs, and within an acceptable timeframe, for decision making, reliability, availability and system management. Additionally, the study aimed to provide relevant and precise information, in order to minimize and mitigate failure actions that may occur, compromising all operational organization base functioning.
Dynamical Analysis of Sputtering at Threshold Energy Range: Modelling of Ar+Ni(100) Collision System
Institute of Scientific and Technical Information of China (English)
HUNDUR Yakup; G(U)VEN(C) Ziya B; HIPPLER Rainer
2008-01-01
The sputtering process of Ar+Ni(100) collision systems is investigated by means of constant energy molecular dynamics simulations.The Ni(100) slab is mimicked by an embedded-atom potential,and the interaction between the projectile and the surface is modelled by using the reparametrized ZBL potential.Ni atom emission from the lattice is analysed over the range of 20-50 eV collision energy.Sputtering yield,angular and energy distributions of the scattered Ar and of the sputtered Ni atoms are calculated,and compared to the available theoretical and experimental data.
Model Based User's Access Requirement Analysis of E-Governance Systems
Saha, Shilpi; Jeon, Seung-Hwan; Robles, Rosslin John; Kim, Tai-Hoon; Bandyopadhyay, Samir Kumar
The strategic and contemporary importance of e-governance has been recognized across the world. In India too, various ministries of Govt. of India and State Governments have taken e-governance initiatives to provide e-services to citizens and the business they serve. To achieve the mission objectives, and make such e-governance initiatives successful it would be necessary to improve the trust and confidence of the stakeholders. It is assumed that the delivery of government services will share the same public network information that is being used in the community at large. In particular, the Internet will be the principal means by which public access to government and government services will be achieved. To provide the security measures main aim is to identify user's access requirement for the stakeholders and then according to the models of Nath's approach. Based on this analysis, the Govt. can also make standards of security based on the e-governance models. Thus there will be less human errors and bias. This analysis leads to the security architecture of the specific G2C application.
Air Force Reusable Booster System: A Quick-look, Design Focused Modeling and Cost Analysis Study
Zapata, Edgar
2011-01-01
This paper presents a method and an initial analysis of the costs of a reusable booster system (RBS) as envisioned by the US Department of Defense (DoD) and numerous initiatives that form the concept of Operationally Responsive Space (ORS). This paper leverages the knowledge gained from decades of experience with the semi-reusable NASA Space Shuttle to understand how the costs of a military next generation semi-reusable space transport might behave in the real world - and how it might be made as affordable as desired. The NASA Space Shuttle had a semi-expendable booster, that being the reusable Solid Rocket MotorslBoosters (SRMlSRB) and the expendable cryogenic External Tank (ET), with a reusable cargo and crew capable orbiter. This paper will explore DoD concepts that invert this architectural arrangement, using a reusable booster plane that flies back to base soon after launch, with the in-space elements of the launch system being the expendable portions. Cost estimating in the earliest stages of any potential, large scale program has limited usefulness. As a result, the emphasis here is on developing an approach, a structure, and the basic concepts that could continue to be matured as the program gains knowledge. Where cost estimates are provided, these results by necessity carry many caveats and assumptions, and this analysis becomes more about ways in which drivers of costs for diverse scenarios can be better understood. The paper is informed throughout with a design-for-cost philosophy whereby the design and technology features of the proposed RBS (who and what, the "architecture") are taken as linked at the hip to a desire to perform a certain mission (where and when), and together these inform the cost, responsiveness, performance and sustainability (how) of the system. Concepts for developing, acquiring, producing or operating the system will be shown for their inextricable relationship to the "architecture" of the system, and how these too relate to costs