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1

A KNOWLEDGE REPOSITORY FOR BEHAVIORAL MODELS IN ENGINEERING DESIGN  

Microsoft Academic Search

Computer simulations and behavioral modeling are becoming increasingly important in product development processes. Simulations can result in better decisions in less time by providing the designers with greater understanding of the product's behavior. However, behavior model creators (i.e. analysts) and behavior model users (i.e. designers) often do not have the same level of understanding of the model, thus limiting the

Gregory Mocko; Richard Malak; Christiaan Paredis; Russell Peak

2004-01-01

2

A Microstructurally Motivated Model of the Mechanical Behavior of Tissue Engineered Blood Vessels  

PubMed Central

Mechanical models have potential to guide the development and use of engineered blood vessels as well as other engineered tissues. This paper presents a microstructurally motivated, pseudoelastic, mechanical model of the biaxial mechanics of engineered vessels in the physiologic pressure range. The model incorporates experimentally measured densities and alignments of engineered collagen. Specifically, these microstructural and associated mechanical inputs were measured directly from engineered blood vessels that were cultured over periods of 5–7.5 weeks. To the best of our knowledge, this is the first successful application of either a phenomenological or a microstructurally motivated mechanical model to engineered vascular tissues. Model development revealed the need to use novel theoretical configurations to describe the strain history of engineered vessels. The constitutive equations developed herein suggested that collagen remodeled between 5 and 7.5 weeks during a 7.5-week culture period. This remodeling led to strain energies for collagen that differed with alignment, which likely resulted from undulations that varied with alignment. Finally, biaxial data emphasized that axial extensions increase stresses in engineered vessels in the physiologic pressure range, thereby providing a guideline for surgical use: engineered vessels should be implanted at appropriate axial extension to minimize adverse stress responses.

Dahl, Shannon L. M.; Vaughn, Megann E.; Hu, Jin-Jia; Driessen, Niels J. B.; Baaijens, Frank P. T.; Humphrey, Jay D.; Niklason, Laura E.

2008-01-01

3

The use of mathematical models to predict beach behavior for U.S. coastal engineering: A critical review  

USGS Publications Warehouse

A number of assumed empirical relationships (e.g., the Bruun Rule, the equilibrium shoreface profile, longshore transport rate equation, beach length: durability relationship, and the renourishment factor) and deterministic numerical models (e.g., GENESIS, SBEACH) have become important tools for investigating coastal processes and for coastal engineering design in the U.S. They are also used as the basis for making public policy decisions, such as the feasibility of nourishing recreational beaches. A review of the foundations of these relationships and models, however, suggests that they are inadequate for the tasks for which they are used. Many of the assumptions used in analytical and numerical models are not valid in the context of modern oceanographic and geologic principles. We believe the models are oversimplifications of complex systems that are poorly understood. There are several reasons for this, including: (1) poor assumptions and important omissions in model formulation; (2) the use of relationships of questionable validity to predict the morphologic response to physical forcing; (3) the lack of hindsighting and objective evaluation of beach behavior predictions for engineering projects; (4) the incorrect use of model calibration and verification as assertions of model veracity; and (5) the fundamental inability to predict coastal evolution quantitatively at the engineering and planning time and space scales our society assumes and demands. It is essential that coastal geologists, beach designers and coastal modelers understand these model limitations. Each important model assumption must be examined in isolation; incorporating them into a model does not improve their validity. It is our belief that the models reviewed here should not be relied on as a design tool until they have been substantially modified and proven in real-world situations. The 'solution,' however, is not to increase the complexity of a model by increasing the number of variables. What is needed is a thoughtful review of what beach behavior questions should or could be answered by modeling. Viable alternatives to the use of models do exist to predict the behavior of beaches. Three such alternatives to models are discussed for nourished beach design.

Thieler, E. R.; Pilkey, Jr. , O. H.; Young, R. S.; Bush, D. M.; Chai, F.

2000-01-01

4

Modeling Behavior with Personalities  

Microsoft Academic Search

Decoupling behavior modeling from a specific inheritance hierarchy has become one of the challenges for object- oriented software engineering. The goal is to encapsulate behavior on its own, and yet be able to freely apply it to a given class structure. We claim that standard object- oriented languages do not directly address this problem and propose the concept of Personalities

Luis Blando; Karl Lieberherr; Mira Mezini

5

Model Behavior  

ERIC Educational Resources Information Center

There are dozens of books and hundreds of resources that address the issue of character development in students: how to raise them to be good people, how to teach them to be good citizens, how to help them to make good decisions. Little is written, however, about the character development of principals and school leaders, whose behavior is a model

Holloway, John

2006-01-01

6

A nonlinear model to analyze the behaviors of the idle speed and the liquid fuel film in gasoline engines  

Microsoft Academic Search

Recent demands for maximum fuel economy, better driveability and minimum exhaust emissions, have placed stringent conditions under which a gasoline engine can operate during idling or transient conditions. To address this problem, a physics based nonlinear model for a four-stroke, multi-point with sequential fueling gasoline engine is developed in this study. The formulation has been structured in such a manner

Chuan He

1996-01-01

7

Modeling of a Diesel Engine with VGT and EGR capturing Sign Reversal and Non-minimum Phase Behaviors  

Microsoft Academic Search

Abstract A mean value model of a diesel engine with VGT and EGR is developed and validated. The intended model applications are system analysis, simulation, and development of model-based control systems. The goal is to construct a model that describes the dynamics in the manifold pressures, turbocharger, EGR, and actuators with few states in order to have short simulation times.

Johan Wahlstrom; Lars Eriksson

2009-01-01

8

Systems Engineering Behavior Study In support of the SELDP program in the Office of the Chief Engineer at NASA HQ  

Microsoft Academic Search

This paper provides a summary of GSFC's System Engineering Leadership Behavior Study and resulting Systems Engineering Competency Model. The study was conducted as part of a larger, Agency-wide initiative to clarify the \\

Carolyn Casey; Matt Jarvis; Edward Amatucci

9

Principles of models based engineering  

SciTech Connect

This report describes a Models Based Engineering (MBE) philosophy and implementation strategy that has been developed at Los Alamos National Laboratory`s Center for Advanced Engineering Technology. A major theme in this discussion is that models based engineering is an information management technology enabling the development of information driven engineering. Unlike other information management technologies, models based engineering encompasses the breadth of engineering information, from design intent through product definition to consumer application.

Dolin, R.M.; Hefele, J.

1996-11-01

10

Behavior of engineered nanoparticles in landfill leachate.  

PubMed

This research sought to understand the behavior of engineered nanoparticles in landfill leachate by examining the interactions between nanoparticles and leachate components. The primary foci of this paper are the effects of ZnO, TiO2, and Ag nanoparticles on biological landfill processes and the form of Zn, Ti, and Ag in leachate following the addition of nanoparticles. Insight into the behavior of nanoparticles in landfill leachate was gained from the observed increase in the aqueous concentrations over background for Zn, Ti, and Ag in some tested leachates attributed to leachate components interacting with the nanoparticle coatings resulting in dispersion, dissolution/dissociation, and/or agglomeration. Coated nanoparticles did not affect biological processes when added to leachate; five-day biochemical oxygen demand and biochemical methane potential results were not statistically different when exposed to nanoparticles, presumably due to the low concentration of dissolved free ionic forms of the associated metals resulting from the interaction with leachate components. Chemical speciation modeling predicted that dissolved Zn in leachate was primarily associated with dissolved organic matter, Ti with hydroxide, and Ag with hydrogen sulfide and ammonia; less than 1% of dissolved Zn and Ag was in the free ionic form, and free ionic Ti and Ag concentrations were negligible. PMID:23799646

Bolyard, Stephanie C; Reinhart, Debra R; Santra, Swadeshmukul

2013-07-10

11

Modeling in chemical engineering  

Microsoft Academic Search

In its 90 year life what has chemical engineering (ChE) contributed to society? Firstly, we have invented and developed processes to create new materials, more gently and more efficiently, so as to make life easier for all.Secondly, ChE has changed our accepted concepts and our ways of thinking in science and technology. Here modeling stands out as the primary development.

Octave Levenspiel

2002-01-01

12

Modeling diesel engine performance  

Microsoft Academic Search

An analytical technique is described to predict the performance of diesel engines. A set of equations are developed from an actual engine test or a performance map to predict fuel consumption as a function of engine speed and torque. The methodology uses a two-dimensional polynomial to predict fuel consumption as a function of engine speed and torque requiring nine engine

G. Jahns; K. J. Forster; P. W. II Claar

1987-01-01

13

A Four-Cylinder Stirling Engine Controls Model.  

National Technical Information Service (NTIS)

A four working space, double acting piston, Stirling engine simulation was developed for controls studies. Two simulations, one for detailed fluid behavior, and a second model with simple fluid behavior but containing the four working space aspects and en...

C. F. Lorenzo C. J. Daniele

1980-01-01

14

Genetically engineered mesenchymal stem cells reduce behavioral deficits in the YAC 128 mouse model of Huntington's disease  

Microsoft Academic Search

The purpose of this study was to evaluate the therapeutic effects of the transplantation of bone-marrow mesenchymal stem cells (MSCs), genetically engineered to over-express brain-derived neurotrophic factor (BDNF) or nerve growth factor (NGF) on motor deficits and neurodegeneration in YAC 128 transgenic mice. MSCs, harvested from mouse femurs, were genetically engineered to over-express BDNF and\\/or NGF and these cells, or

Nicholas D. Dey; Matthew C. Bombard; Bartholomew P. Roland; Stacy Davidson; Ming Lu; Julien Rossignol; Michael I. Sandstrom; Reid L. Skeel; Laurent Lescaudron; Gary L. Dunbar

2010-01-01

15

Four-cylinder Stirling engine controls model  

SciTech Connect

A four working space, double-acting piston, Stirling engine simulation is being developed for controls studies. The development method is to construct two simulations, one for detailed fluid behavior, and a second model with simple fluid behaviour but containing the four working space aspects and engine inertias, validate these models separately, then upgrade the four working space model by incorporating the detailed fluid behavior model for all four working spaces. The single working space (SWS) model contains the detailed fluid dynamics. It has seven control volumes in which continuity, energy, and pressure loss effects are simulated. Comparison of the SWS model with experimental data shows reasonable agreement in net power versus speed characteristics for various mean pressure levels in the working space. The four working space (FWS) model was built to observe the behavior of the whole engine. The drive dynamics and vehicle inertia effects are simulated. To reduce calculation time, only three volumes are used in each working space and the gas temperatures are fixed (no energy equation). Comparison of the FWS model predicted power with experimental data shows reasonable agreement. Since all four working spaces are simulated, the unique capabilities of the model are exercised to look at working fluid supply transients, short circuit transients, and piston ring leakage effects. The FWS model has been upgraded by using the detailed SWS model for each of the four working spaces. Currently the detailed FWS model is being reworked to reduce the amount of calculation time per cycle.

Lorenzo, C.F.; Daniele, C.J.

1980-01-01

16

Simulation of Diesel Engine Transient Behavior in Marine Propulsion Analysis.  

National Technical Information Service (NTIS)

Diesel engine simulation models are developed, based on a combination of engine operational principles and manufacturers' operational data. The models are intended to be suitable for use in transient modeling the propulsion engine part of marine propulsio...

J. B. Woodward R. G. Latorre

1983-01-01

17

Mathematical Modeling of Beach Behavior Doesn't Work  

Microsoft Academic Search

I ABSTRACT The use of mathematical,modeling to predict the behavior of beaches does not work. Some of the major assumptions behind the models , by studying its past behavior. Keywords: Engineering and environmental geol-

Orrin H. Pilkey

1994-01-01

18

Project C: Microstructural Engineering in Hot-Strip Mills. Part 2 of 2: Constitutive Behavior Modeling of Steels Under Hot-Rolling Conditions. Final Report May 1, 1993-April 30, 1998.  

National Technical Information Service (NTIS)

This report describes the work done at NIST/Boulder for the Microstructural Engineering in Hot-Strip Mills project. The objective of Subtask C2.5 is to develop constitutive models to predict stress-strain behavior of steels under hot-rolling conditions an...

1998-01-01

19

Pulse Detonation Engine Modeled.  

National Technical Information Service (NTIS)

Pulse Detonation Engine Technology is currently being investigated at Glenn for both airbreathing and rocket propulsion applications. The potential for both mechanical simplicity and high efficiency due to the inherent near-constant-volume combustion proc...

D. E. Paxson

2001-01-01

20

Rocket engine diagnostics using qualitative modeling techniques  

NASA Astrophysics Data System (ADS)

Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system was created. The qualitative model describes the effects of seal failures on the system steady state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures.

Binder, Michael; Maul, William; Meyer, Claudia; Sovie, Amy

1992-07-01

21

Rocket engine diagnostics using qualitative modeling techniques  

NASA Astrophysics Data System (ADS)

Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system has been created. The qualitative model describes the effects of seal failures on the system steady-state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures.

Binder, Michael; Maul, William; Meyer, Claudia; Sovie, Amy

1992-07-01

22

Models for citation behavior  

Microsoft Academic Search

The number of citations of journal papers is an important measure of the impact of research. Thus, the modeling of citation\\u000a behavior needs attention. Burrell, Egghe, Rousseau and others pioneered this type of modeling. Several models have been proposed\\u000a for the citation distribution. In this note, we derive the most comprehensive collection of formulas for the citation distribution,\\u000a covering some

Saralees Nadarajah; Samuel Kotz

2007-01-01

23

Model Engineering using Multimodeling.  

National Technical Information Service (NTIS)

We study the simultaneous use of multiple modeling techniques in the design of embedded systems. We begin with a pre-existing Statecharts model of a simple case study, a traffic light for a pedestrian crossing. This model combines two distinct models of c...

C. Brooks C. P. Cheng E. A. Lee R. Von Hanxleden T. H. Feng

2008-01-01

24

Leading engineering teams: leader behaviors related to team performance  

Microsoft Academic Search

The author examines the relationship between leader behaviors and engineering team performance. Data were collected for 18 engineering teams (nine research, nine nonresearch) from manufacturing and aerospace organizations located in Rocky Mountain, Midwest, and East Coast regions of the United States. Results indicate that both team members and leaders believed that providing autonomy and initiating structure were important leader behaviors;

Judith A. Kolb

1993-01-01

25

On modeling program behavior  

Microsoft Academic Search

This is a paper about the history of the working set model for program behavior. It traces briefly the origins and bases of the idea and some of the results subsequently obtained. The physical context is a hierarchical memory system consisting of a severely limited quantity of main (directly-addressable) storage and an essentially unlimited quantity of secondary (backup) storage. In

Peter J. Denning

1972-01-01

26

Toward a Web Search Information Behavior Model  

NASA Astrophysics Data System (ADS)

Information retrieval (IR) research in the context of the Web involves a number of complex processes. Some are user-related and include cognitive processes, motivational issues, information needs, technology attitude and adoption; and some are system related and include search engine algorithms and interface design. The field currently lacks a comprehensive model of Web interaction in the information behavior context. This chapter first explores a range of information behavior, and information seeking and retrieval model. Research relating to how users seek out and retrieve information in electronic environments will be examined and these models considered for applicability to the information environment of the Web. The exploration begins at the broadest level, examining information seeking models and then interactive IR models, followed by more recent integrated models. The paper then proposes macro model of Web-based information seeking and searching behavior. Further research areas are also discussed.

Knight, S. A.; Spink, A.

27

Modeling and Control of CNG Engines  

Microsoft Academic Search

CNG engines are now recognized to be an interesting alternative to classical IC engines because of low pollutant and carbon dioxide emissions. This paper will first briefly summarize these advantages quantitatively and then concentrate on the modeling and the control of CNG engines. In the modeling part it will be shown which effects are similar to SI engines and what

David Dyntar; Christopher Onder; Lino Guzzella

28

Graphical animation of behavior models  

Microsoft Academic Search

Graphical animation is a way of visualizing the behavior of design models. This visualization is of use in validating a design model against informally specified requirements and in interpreting the meaning and significance of analysis results in relation to the problem domain. In this paper we describe how behavior models specified by Labeled Transition Systems (LTS) can drive graphical animations.

Jeff Magee; Nat Pryce; Dimitra Giannakopoulou; Jeff Kramer

2000-01-01

29

A Generic, Adaptive Systems Engineering Information Model  

Microsoft Academic Search

Systems engineering tasks generate large volumes of data and information that must be available over the lifecycle of the system. This paper outlines an information model designed to support existing systems engineering methods and practices as well newly developed techniques. Specific methods and models used for the capture, encoding and persistence of systems engineering information and design artifacts were given

Joseph J. Simpson; Scott Grasman; Ann Miller; Cihan Dagli

2005-01-01

30

Modeling and predicting behavioral dynamics on the web  

Microsoft Academic Search

User behavior on the Web changes over time. For example, the queries that people issue to search engines, and the underlying informational goals behind the queries vary over time. In this paper, we examine how to model and predict this temporal user behavior. We develop a temporal modeling framework adapted from physics and signal processing that can be used to

Kira Radinsky; Krysta M. Svore; Susan T. Dumais; Jaime Teevan; Alex Bocharov; Eric Horvitz

2012-01-01

31

Modeling the internal combustion engine  

SciTech Connect

A flexible and computationally economical model of the internal combustion engine was developed for use on large digital computer systems. It is based on a system of ordinary differential equations for cylinder-averaged properties. The computer program is capable of multicycle calculations, with some parameters varying from cycle to cycle, and has restart capabilities. It can accommodate a broad spectrum of reactants, permits changes in physical properties, and offers a wide selection of alternative modeling functions without any reprogramming. It readily adapts to the amount of information available in a particular case because the model is in fact a hierarchy of five models. The models range from a simple model requiring only thermodynamic properties to a complex model demanding full combustion kinetics, transport properties, and poppet valve flow characteristics. Among its many features the model includes heat transfer, valve timing, supercharging, motoring, finite burning rates, cycle-to-cycle variations in air-fuel ratio, humid air, residual and recirculated exhaust gas, and full combustion kinetics.

Zeleznik, F.J.; Mcbride, B.J.

1985-03-01

32

Modeling of a turbocharged SI engine  

Microsoft Academic Search

Turbocharged SI engines are a major possibility in the current trend of down-sized engines with preserved drivability performance. Considering control and supervision it is favorable to have a mean value model to be used e.g. in observer design. Such models of turbo engines are similar to those of naturally aspirated engines, but there are some special characteristics, e.g. the interconnected

Lars Eriksson; Lars Nielsen; Jan Brugård; Johan Bergström; Fredrik Pettersson; Per Andersson

2002-01-01

33

Combustion Modelling in Automotive Engines  

Microsoft Academic Search

Before the emissions and energy crises were upon us, it was enough that automotive engines worked. We could develop in a leisurely way our basic understanding of engine combustion problems. It is now obvious that the current automobile engine's problems of high emissions and deteriorating fuel economy must be rapidly solved. It is likely that new engine concepts must be

John B. Heywood

1974-01-01

34

An algebraic approach to modeling in software engineering  

SciTech Connect

Our work couples the formalism of universal algebras with the engineering techniques of mathematical modeling to develop a new approach to the software engineering process. Our purpose in using this combination is twofold. First, abstract data types and their specification using universal algebras can be considered a common point between the practical requirements of software engineering and the formal specification of software systems. Second, mathematical modeling principles provide us with a means for effectively analyzing real-world systems. We first use modeling techniques to analyze a system and then represent the analysis using universal algebras. The rest of the software engineering process exploits properties of universal algebras that preserve the structure of our original model. This paper describes our software engineering process and our experience using it on both research and commercial systems. We need a new approach because current software engineering practices often deliver software that is difficult to develop and maintain. Formal software engineering approaches use universal algebras to describe ``computer science`` objects like abstract data types, but in practice software errors are often caused because ``real-world`` objects are improperly modeled. There is a large semantic gap between the customer`s objects and abstract data types. In contrast, mathematical modeling uses engineering techniques to construct valid models for real-world systems, but these models are often implemented in an ad hoc manner. A combination of the best features of both approaches would enable software engineering to formally specify and develop software systems that better model real systems. Software engineering, like mathematical modeling, should concern itself first and foremost with understanding a real system and its behavior under given circumstances, and then with expressing this knowledge in an executable form.

Loegel, G.J. [Superconducting Super Collider Lab., Dallas, TX (United States)]|[Michigan Univ., Ann Arbor, MI (United States); Ravishankar, C.V. [Michigan Univ., Ann Arbor, MI (United States)

1993-09-01

35

Information Technology Ethical Behavior: Toward a Comprehensive Ethical Behavior Model  

Microsoft Academic Search

This research work advances IT eth- ics research by surveying the literature regarding IT ethical behavior models and further proposes a comprehensive IT ethi- cal behavioral model. Based on an initial meta-analysis of some of the ethical re- search, a conceptual ethical behavior model is proposed. The proposed model sug- gests that ethical behavioral intention is influenced by an individual's

Timothy Paul Cronan; David E. Douglas

36

Control engineering and related systems approaches for improving behavioral health  

Microsoft Academic Search

The goal of this special session is to describe emerging approaches and research opportunities for control engineering in a developing research topic of important societal significance. Specifically, we explore how control systems and related approaches from systems science can be applied to the prevention and treatment of chronic behavioral disorders; these include drug and alcohol abuse, depression, HIV\\/AIDS, cancer, diabetes,

Daniel E. Rivera; Fahmida Chowdhury

2009-01-01

37

Engineering animal models of dystonia.  

PubMed

Dystonia is a neurological disorder characterized by abnormal involuntary movements that are prolonged and often cause twisting and turning. Several genetically modified worms, fruit flies, and rodents have been generated as models of genetic dystonias, in particular DYT1, DYT11, and DYT12 dystonias. Although these models do not show overt dystonic symptoms, the rodent models exhibit motor deficits in specialized behavioral tasks, such as the rotarod and beam-walking tests. For example, in a rodent model of DYT12 dystonia, which is generally stress triggered, motor deficits are observed only after the animal is stressed. Moreover, in a rodent model of DYT1 dystonia, the motor and electrophysiological deficits can be rescued by trihexyphenidyl, a common anticholinergic medication used to treat dystonic symptoms in human patients. Biochemically, the DYT1 and DYT11 animal models also share some similarities to patients, such as a reduction in striatal D2 dopamine receptor and binding activities. In addition, conditional knockout mouse models for DYT1 and DYT11 dystonia demonstrate that loss of the causal dystonia-related proteins in the striatum leads to motor deficits. Interestingly, loss of the DYT1 dystonia causal protein in Purkinje cells shows an improvement in motor performance, suggesting that gene therapy targeting of the cerebellum or intervention in its downstream pathways may be useful. Finally, recent studies using DYT1 dystonia worm and mouse models led to a potential novel therapeutic agent, which is currently undergoing clinical trials. These results indicate that genetic animal models are powerful tools to elucidate the pathophysiology and to further develop new therapeutics for dystonia. PMID:23893455

Oleas, Janneth; Yokoi, Fumiaki; Deandrade, Mark P; Pisani, Antonio; Li, Yuqing

2013-06-15

38

Multitasking Driver Cognitive Behavior Modeling  

Microsoft Academic Search

In order to process multitasking driver behavior effectively, an improved driver cognitive behavior modeling method of ACT-R is proposed in this paper. The manual module and visual module of ACT-R are concatenated directly to cope with human subconscious\\/unconscious behavior. A parallel processing method is proposed to mimic the parallel reactions style of a given cerebral area of human brain's reaction

Yanfei Liu; Zhaohui Wu

2006-01-01

39

Surrogate Model Development for Fuels for Advanced Combustion Engines  

Microsoft Academic Search

The fuels used in internal-combustion engines are complex mixtures of a multitude of different types of hydrocarbon species. Attempting numerical simulations of combustion of real fuels with all of the hydrocarbon species included is highly unrealistic. Thus, a surrogate model approach is generally adopted, which involves choosing a few representative hydrocarbon species whose overall behavior mimics the characteristics of the

Krishnasamy Anand; youngchul Ra; Rolf Reitz; Bruce G Bunting

2011-01-01

40

CONFIG: Qualitative Simulation Tool for Analyzing Behavior of Engineering Devices.  

National Technical Information Service (NTIS)

To design failure management expert systems, engineers mentally analyze the effects of failures and procedures as they propagate through device configurations. CONFIG is a generic device modeling tool for use in discrete event simulation, to support such ...

J. T. Malin B. D. Basham R. A. Harris

1987-01-01

41

Protective behavior in matching models  

Microsoft Academic Search

This paper analyzes the use of a version of lexical maximim strategies, called protective behavior, in two-sided matching models. It restricts attention to mechanisms which produce stable matchings, that is, matchings which are individually rational and pairwise optimal. The main results of the paper show that truth-telling is the unique form of protective behavior in two such mechanisms. The first

B. Dutta

1995-01-01

42

A Transformation Model of Engineering Education  

ERIC Educational Resources Information Center

A transformation model of engineering education at the undergraduate level is constructed to define the human and technical resources that contribute to the production of a university-trained engineer. The theory of technical systems is applied in the development of the model to transform a graduating pre-university pupil into a university-trained…

Owens, Camelia L.; Fortenberry, Norman L.

2007-01-01

43

Conceptual Models for Search Engines  

Microsoft Academic Search

Search engines have entered popular culture. They touch people in diverse private and public settings and thus heighten the importance of such important social matters as information privacy and control, censorship, and equitable access. To fully benefit from search engines and to participate in debate about their merits, people necessarily appeal to their understandings for how they function. In this

D. G. Hendry; E. N. Efthimiadis

2008-01-01

44

Measuring Model Rocket Engine Thrust Curves  

ERIC Educational Resources Information Center

|This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…

Penn, Kim; Slaton, William V.

2010-01-01

45

A transient SI engine model for vehicle dynamic simulation. Ph.D. Thesis  

SciTech Connect

This study details an investigation into the modeling and simulation of spark-ignition (SI) engines, engine components, and vehicle powertrain systems. The work expands on previous studies in three areas: the description of powertrain system and its components, the formulation of SI engine component models and overall engine model, and lastly, the sensitivity analysis of the engine model and the simulation of powertrain systems. A mathematical model of SI engines, with either carburator, single-port fuel injection, or multi-port fuel injection systems, is derived. In the present engine model, the engine internal torque is a function of air/fuel ratio, engine speed, and throttle plate position. This engine model can account for the sudden change in throttle plate angle and estimate the engine transient behavior. The powertrain subsystems are also described to a certain extent, and the integration of the present engine model and a specific powertrain system is verified by further computer simulation. The Taguchi method is applied in sensitivity analysis (constant engine speed) which allows for an understanding of the engine parameters that are necessary to include in the model. In addition, the control variables which affect the engine dynamics and states can be examined. Using the simulation results, a simple fuel enrichment strategy is derived in order to compensate air-fuel mixture lean/rich tendency when the throttle plate is opened/closed rapidly. This confirms the controllability of the present engine model. Furthermore, a flywheel is attached to the engine crankshaft to emulate a powertrain system and account for the change in engine speed. Finally, the present engine model and a specific powertrain system are integrated and simulated to demonstrate their application in full-vehicle simulation.

Huang, R.W.

1994-01-01

46

Evaluation of Conceptual Models of Behavior Disorders.  

ERIC Educational Resources Information Center

This article reviews the psychoeducational, behavioral, and ecological models underlying educational services to students with behavior disorders. Models are compared for their explanatory nature, implications for intervention, and how they address the scientific approach to behavior disorders. (DB)

Cullinan, Douglas; And Others

1991-01-01

47

Engineering of Framework-Specific Modeling Languages  

Microsoft Academic Search

Framework-specific modeling languages (FSMLs) help developers build applications based on object-oriented frameworks. FSMLs model abstractions and rules of application programming interfaces (APIs) exposed by frameworks and can express models of how applications use APIs. Such models aid developers in understanding, creating, and evolving application code. We present four exemplar FSMLs and a method for engineering new FSMLs. The method was

Michal Antkiewicz; Krzysztof Czarnecki; Matthew Stephan

2009-01-01

48

Planar Biaxial Behavior of Fibrin-Based Tissue-Engineered Heart Valve Leaflets  

PubMed Central

To design more effective tissue-engineered heart valve replacements, the replacement tissue may need to mimic the biaxial stress–strain behavior of native heart valve tissue. This study characterized the planar biaxial properties of tissue-engineered valve leaflets and native aortic valve leaflets. Fibrin-based valve equivalent (VE) and porcine aortic valve (PAV) leaflets were subjected to incremental biaxial stress relaxation testing, during which fiber alignments were measured, over a range of strain ratios. Results showed that VE leaflets exhibited a modulus and fiber reorientation behavior that correlated with strain ratio. In contrast, PAV leaflets maintained their relaxed modulus and fiber alignment when exposed to nonequibiaxial strain, but exhibited changes in stress relaxation. In uniaxial and equi-biaxial tension, there were few observed differences in relaxation behavior between VE and PAV leaflets, despite differences in the modulus and fiber reorientation. Likewise, in both tissues there was similar relaxation response in the circumferential and radial directions in biaxial tension, despite different moduli in these two directions. This study presents some fundamental differences in the mechanical response to biaxial tension of fibrin-based tissue-engineered constructs and native valve tissue. It also highlights the importance of using a range of strain ratios when generating mechanical property data for valvular and engineered tissues. The data presented on the stress–strain, relaxation, and fiber reorientation of VE tissue will be useful in future efforts to mathematically model and improve fibrin-based tissue-engineered constructs.

Robinson, Paul S.

2009-01-01

49

Preliminary results from a four-working space, double-acting piston, Stirling engine controls model  

Microsoft Academic Search

A four-working space, double-acting piston, Stirling engine simulation is being developed for controls studies. The development method is to construct two simulations, one for detailed fluid behavior, and a second model with simple fluid behavior but containing the four working space aspects and engine inertias, validate these models separately, then upgrade the four-working space model by incorporating the detailed fluid

C. J. Daniele; C. F. Lorenzo

1980-01-01

50

Behavior model for performance assessment  

SciTech Connect

Identifying individual mental mechanisms or processes, organizing the individual strategies of these mechanisms into useful patterns, and formulating these into models for success and knowledge-based outcomes is easily done and can be accomplished through the use of neurological cues. Once identified, analog models can be constructed from the cues, and tree analysis models can be developed and then digitized through such methods as Bayesian concepts or a continuous wavelet transform. The authors are intent upon understanding behavior and constructing models from a macro level of understanding the process. The author has yet to accept the fact that the author needs to understand the how at the micro level of strategy building. Knowing what to observe and how to state questions so as to gather precise information regarding strategies being processed provides the means to refine those models existing today to be more effective in their analysis of human behaviors.

Brown-VanHoozer, S.A.

1999-07-01

51

Generalization of the Software Engineering Maturity Model.  

National Technical Information Service (NTIS)

The software process consists of the methods, practices, and tools used to generate a software product. The Software Engineering Institute at Carnegie Mellon University has developed a capability maturity model (CMM) which defines five levels of maturity ...

K. G. Brammer J. H. Brill

1993-01-01

52

Behavior model for performance assessment.  

SciTech Connect

Every individual channels information differently based on their preference of the sensory modality or representational system (visual auditory or kinesthetic) we tend to favor most (our primary representational system (PRS)). Therefore, some of us access and store our information primarily visually first, some auditorily, and others kinesthetically (through feel and touch); which in turn establishes our information processing patterns and strategies and external to internal (and subsequently vice versa) experiential language representation. Because of the different ways we channel our information, each of us will respond differently to a task--the way we gather and process the external information (input), our response time (process), and the outcome (behavior). Traditional human models of decision making and response time focus on perception, cognitive and motor systems stimulated and influenced by the three sensory modalities, visual, auditory and kinesthetic. For us, these are the building blocks to knowing how someone is thinking. Being aware of what is taking place and how to ask questions is essential in assessing performance toward reducing human errors. Existing models give predications based on time values or response times for a particular event, and may be summed and averaged for a generalization of behavior(s). However, by our not establishing a basic understanding of the foundation of how the behavior was predicated through a decision making strategy process, predicative models are overall inefficient in their analysis of the means by which behavior was generated. What is seen is the end result.

Borwn-VanHoozer, S. A.

1999-07-23

53

Relationship Quality and the Theory of Planned Behavior models of behavioral intentions and purchase behavior  

Microsoft Academic Search

Using real-life purchase behavior data of apparel and survey information, this study compares the Relationship Quality and the Theory of Planned Behavior models. The attitude towards the buying behavior, the subjective norm and perceived behavioral control (antecedents of the buying intention in the Theory of Planned Behavior) are better predictors of behavioral intentions than Relationship Quality. In both models intentions

Marie Hélène De Cannière; Patrick De Pelsmacker; Maggie Geuens

2009-01-01

54

Relationship Quality and the Theory of Planned Behavior Models of Behavioral Intentions and Purchase Behavior  

Microsoft Academic Search

Using real-life purchase behavior data of apparel and survey information, this study compares the Relationship Quality and the Theory of Planned Behavior models. The attitude towards the buying behavior, the subjective norm and perceived behavioral control (antecedents of the buying intention in the Theory of Planned Behavior) are better predictors of behavioral intentions than Relationship Quality. In both models intentions

M. H. DE CANNIÈRE; P. DE PELSMACKER; M. GEUENS

2008-01-01

55

Parametric fault modeling and diagnostics of a turbofan engine  

Microsoft Academic Search

A parametric fault modeling and diagnostics approach of a turbofan engine is presented. The healthy engine model is obtained as a steady state map between input parameters representing engine operating conditions and output parameters governing engine performance characteristics. The fault modeling is conceptualized as either degraded engine performance levels or as sensor failures and both incipient and abrupt fault scenarios

S. Ganguli; S. Deo; D. Gorinevsky

2004-01-01

56

Behavior modelling during software design  

Microsoft Academic Search

A modelling scheme is presented which provides a medium for the rigorous, formal and abstract specification of large-scale software system components. The scheme allows the description of component behavior without revealing or requiring the description of a component's internal operation. Both collections of sequential processes and the data objects which they share may be described. The scheme is of particular

William E. Riddle; Jack C. Wileden; John H. Sayler; Alan R. Segal; Allan M. Stavely

1978-01-01

57

A crankshaft system model for structural dynamic analysis of internal combustion engines  

Microsoft Academic Search

A system model for analyzing the dynamic behavior of an internal combustion engine crankshaft is described. The model couples the crankshaft structural dynamics, the main bearing hydrodynamic lubrication and the engine block stiffness using a system approach. A two-level dynamic substructuring technique is used to predict the crankshaft dynamic response based on the finite-element method. The dynamic substructuring uses a

Zissimos P. Mourelatos

2001-01-01

58

A Simple HCCI Engine Model for Control  

SciTech Connect

The homogeneous charge compression ignition (HCCI) engine is an attractive technology because of its high efficiency and low emissions. However, HCCI lacks a direct combustion trigger making control of combustion timing challenging, especially during transients. To aid in HCCI engine control we present a simple model of the HCCI combustion process valid over a range of intake pressures, intake temperatures, equivalence ratios, and engine speeds. The model provides an estimate of the combustion timing on a cycle-by-cycle basis. An ignition threshold, which is a function of the in-cylinder motored temperature and pressure is used to predict start of combustion. This model allows the synthesis of nonlinear control laws, which can be utilized for control of an HCCI engine during transients.

Killingsworth, N; Aceves, S; Flowers, D; Krstic, M

2006-06-29

59

Clinician Search Behaviors May Be Influenced by Search Engine Design  

PubMed Central

Background Searching the Web for documents using information retrieval systems plays an important part in clinicians’ practice of evidence-based medicine. While much research focuses on the design of methods to retrieve documents, there has been little examination of the way different search engine capabilities influence clinician search behaviors. Objectives Previous studies have shown that use of task-based search engines allows for faster searches with no loss of decision accuracy compared with resource-based engines. We hypothesized that changes in search behaviors may explain these differences. Methods In all, 75 clinicians (44 doctors and 31 clinical nurse consultants) were randomized to use either a resource-based or a task-based version of a clinical information retrieval system to answer questions about 8 clinical scenarios in a controlled setting in a university computer laboratory. Clinicians using the resource-based system could select 1 of 6 resources, such as PubMed; clinicians using the task-based system could select 1 of 6 clinical tasks, such as diagnosis. Clinicians in both systems could reformulate search queries. System logs unobtrusively capturing clinicians’ interactions with the systems were coded and analyzed for clinicians’ search actions and query reformulation strategies. Results The most frequent search action of clinicians using the resource-based system was to explore a new resource with the same query, that is, these clinicians exhibited a “breadth-first” search behaviour. Of 1398 search actions, clinicians using the resource-based system conducted 401 (28.7%, 95% confidence interval [CI] 26.37-31.11) in this way. In contrast, the majority of clinicians using the task-based system exhibited a “depth-first” search behavior in which they reformulated query keywords while keeping to the same task profiles. Of 585 search actions conducted by clinicians using the task-based system, 379 (64.8%, 95% CI 60.83-68.55) were conducted in this way. Conclusions This study provides evidence that different search engine designs are associated with different user search behaviors.

Coiera, Enrico; Zrimec, Tatjana; Compton, Paul

2010-01-01

60

Exploring cognitive modelling in engineering usability design  

Microsoft Academic Search

Engineering practice moves towards user-centred product design. Without effective computer-aided design tools, relying only on subjective guidelines in design and user testing in prototyping has made usability design expensive and time-consuming. This paper explores how modern cognitive modelling (CogM) can systematically address the challenges facing engineering usability design. A CogM-aided design paradigm is investigated for the different requirements of conceptual

Xiangyang Li; Melih Gunal

2010-01-01

61

Exploring cognitive modelling in engineering usability design  

Microsoft Academic Search

Engineering practice moves towards user-centred product design. Without effective computer-aided design tools, relying only on subjective guidelines in design and user testing in prototyping has made usability design expensive and time-consuming. This paper explores how modern cognitive modelling (CogM) can systematically address the challenges facing engineering usability design. A CogM-aided design paradigm is investigated for the different requirements of conceptual

Xiangyang Li; Melih Gunal

2012-01-01

62

Systems engineering interfaces: A model based approach  

NASA Astrophysics Data System (ADS)

The engineering of interfaces is a critical function of the discipline of Systems Engineering. Included in interface engineering are instances of interaction. Interfaces provide the specifications of the relevant properties of a system or component that can be connected to other systems or components while instances of interaction are identified in order to specify the actual integration to other systems or components. Current Systems Engineering practices rely on a variety of documents and diagrams to describe interface specifications and instances of interaction. The SysML[1] specification provides a precise model based representation for interfaces and interface instance integration. This paper will describe interface engineering as implemented by the Operations Revitalization Task using SysML, starting with a generic case and culminating with a focus on a Flight System to Ground Interaction. The reusability of the interface engineering approach presented as well as its extensibility to more complex interfaces and interactions will be shown. Model-derived tables will support the case studies shown and are examples of model-based documentation products.

Fosse, E.; Delp, C. L.

63

Modified Linear Parameter Varying modeling for turbofan engine  

Microsoft Academic Search

A modified LPV (Linear Parameter Varying) modeling method for nonlinear system was put forward and is applied in modeling a turbofan engine system. First, a quasi-LPV model of a turbofan engine is designed at various engine operating points using linearized models of the engine dynamics and the scheduling variable is the low-pressure compressor speed. Then, according to the feedback method,

Li Shu-qing; Zhang Sheng-xiu

2010-01-01

64

LES Modeling of Diesel Engines  

Microsoft Academic Search

In this study, a one-equation LES sub-grid model from Menon, et al. (5) is used in simulating the diesel combustion process. In addition, based on the one- equation methodology of Menon et al., a new one- equation LES scalar transport model is formulated. These models allow for the turbulent transfer coefficients for both momentum and scalar flux to be determined

Daniel Lee; Eric Pomraning; Christopher J. Rutland

2002-01-01

65

Matrix models, geometric engineering and elliptic genera  

Microsoft Academic Search

We compute the prepotential of Script N = 2 supersymmetric gauge theories in four dimensions obtained by toroidal compactifications of gauge theories from 6 dimensions, as a function of Kähler and complex moduli of T2. We use three different methods to obtain this: matrix models, geometric engineering and instanton calculus. Matrix model approach involves summing up planar diagrams of an

Timothy J. Hollowood; Amer Iqbal; Cumrun Vafa

2008-01-01

66

Performance Engineering in the Community Atmosphere Model  

SciTech Connect

The Community Atmosphere Model (CAM) is the atmospheric component of the Community Climate System Model (CCSM) and is the primary consumer of computer resources in typical CCSM simulations. Performance engineering has been an important aspect of CAM development throughout its existence. This paper briefly summarizes these efforts and their impacts over the past five years.

Worley, P; Mirin, A; Drake, J; Sawyer, W

2006-05-30

67

A Model Undergraduate Electrical Engineering Curriculum  

Microsoft Academic Search

This paper presents a model curriculum as developed by an ad hoc group of five managers, each from a large industrial employer of electrical engineers. The model itself is the result of compromise between conflicting viewpoints, for, after all, there are many different job opportunities implying the need for a variety of educational emphases. The committee finds little fault in

Clarence J. Baldwin; Charles R. Cahn; John W. Forman; Henry Lehmann; Carl R. Wischmeyer

1979-01-01

68

Threads vs. caches: Modeling the behavior of parallel workloads  

Microsoft Academic Search

A new generation of high-performance engines now combine graphics-oriented parallel processors with a cache architecture. In order to meet this new trend, new highly- parallel workloads are being developed. However, it is often difficult to predict how a given application would perform on a given architecture. This paper provides a new model capturing the behavior of such parallel workloads on

Zvika Guz; Oved Itzhak; Idit Keidar; Avinoam Kolodny; Avi Mendelson; Uri C. Weiser

2010-01-01

69

Teaching Behavioral Modeling and Simulation Techniques for Power Electronics Courses  

ERIC Educational Resources Information Center

|This paper suggests a pedagogical approach to teaching the subject of behavioral modeling of switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The methodology is oriented toward electrical engineering (EE) students at the undergraduate level, enrolled in courses such as "Power Electronics,"…

Abramovitz, A.

2011-01-01

70

Energy and technology review: Engineering modeling  

SciTech Connect

This report presents information concerning: Modeling Canonical Problems in Electromagnetic Coupling Through Apertures; Finite-Element Codes for Computing Electrostatic Fields; Finite-Element Modeling of Electromagnetic Phenomena; Modeling Microwave-Pulse Compression in a Resonant Cavity; Lagrangian Finite-Element Analysis of Penetration Mechanics; Crashworthiness Engineering; Computer Modeling of Metal-Forming Processes; Thermal-Mechanical Modeling of Tungsten Arc Welding; Modeling Air Breakdown Induced by Electromagnetic Fields; Iterative Techniques for Solving Boltzmann's Equations for p-Type Semiconductors; Semiconductor Modeling; and Improved Numerical-Solution Techniques in Large-Scale Stress Analysis.

Cabayan, H.S.; Goudreau, G.L.; Ziolkowski, R.W.; Adye, P.; Clements, W.; Crawford, R.B.; de Vore, L.; Hendry, D.P.; Kirvel, R.D.; O'Neal, E.M. (eds.)

1986-10-01

71

A behavior model for persuasive design  

Microsoft Academic Search

This paper presents a new model for understanding human behavior. In this model (FBM), behavior is a product of three factors: motivation, ability, and triggers, each of which has subcomponents. The FBM asserts that for a person to perform a target behavior, he or she must (1) be sufficiently motivated, (2) have the ability to perform the behavior, and (3)

B. J. Fogg

2009-01-01

72

A moderation model of political behavior  

Microsoft Academic Search

The study tests a moderation model of political behavior. Specifically, we propose that an individual's perceptions of organizational politics (POPs) influence his or her own political behavior engagement, while the POPs-political behavior linkage varies across different individual political skill levels. For those politically skilled individuals, the POPs-political behavior relationship will be positively stronger. In the model we also specify the

Liu Jun; Yu Guang-tao; Liu Gang

2009-01-01

73

Reliable modeling of complex behavior  

SciTech Connect

The status of modeling for large-strain plasticity is assessed, and this overview is used to emphasize some general points concerning modeling in Materials Science. While a physical foundation is essential in order to achieve generality and some measure of confidence in extrapolations, phenomenological constraint is equally crucial to achieve reliability and predictive value in descriptions of the macroscopic behavior despite the enormous complexity of the underlying physics. Many details that may be of interest in modeling the physical foundation lose importance in the integration to an overall materials response, which depends on few parameters and is quite reproducible. From this point of view, the current understanding of large-strain plasticity is adequate in many respects. However, some problems are highlighted in which more quantitative modeling results would impact the reliability and generality of macroscopic properties descriptions, and which seem amenable to treatment with current techniques and resources. 21 refs., 6 figs., 1 tab.

Kocks, U.F.

1991-01-01

74

Statistical and engineering methods for model enhancement  

NASA Astrophysics Data System (ADS)

Models which describe the performance of physical process are essential for quality prediction, experimental planning, process control and optimization. Engineering models developed based on the underlying physics/mechanics of the process such as analytic models or finite element models are widely used to capture the deterministic trend of the process. However, there usually exists stochastic randomness in the system which may introduce the discrepancy between physics-based model predictions and observations in reality. Alternatively, statistical models can be used to develop models to obtain predictions purely based on the data generated from the process. However, such models tend to perform poorly when predictions are made away from the observed data points. This dissertation contributes to model enhancement research by integrating physics-based model and statistical model to mitigate the individual drawbacks and provide models with better accuracy by combining the strengths of both models. The proposed model enhancement methodologies including the following two streams: (1) data-driven enhancement approach and (2) engineering-driven enhancement approach. Through these efforts, more adequate models are obtained, which leads to better performance in system forecasting, process monitoring and decision optimization. Among different data-driven enhancement approaches, Gaussian Process (GP) model provides a powerful methodology for calibrating a physical model in the presence of model uncertainties. However, if the data contain systematic experimental errors, the GP model can lead to an unnecessarily complex adjustment of the physical model. In Chapter 2, we proposed a novel enhancement procedure, named as “Minimal Adjustment”, which brings the physical model closer to the data by making minimal changes to it. This is achieved by approximating the GP model by a linear regression model and then applying a simultaneous variable selection of the model and experimental bias terms. Two real examples and simulations are presented to demonstrate the advantages of the proposed approach. Different from enhancing the model based on data-driven perspective, an alternative approach is to focus on adjusting the model by incorporating the additional domain or engineering knowledge when available. This often leads to models that are very simple and easy to interpret. The concepts of engineering-driven enhancement are carried out through two applications to demonstrate the proposed methodologies. In the first application where polymer composite quality is focused, nanoparticle dispersion has been identified as a crucial factor affecting the mechanical properties. Transmission Electron Microscopy (TEM) images are commonly used to represent nanoparticle dispersion without further quantifications on its characteristics. In Chapter 3, we developed the engineering-driven nonhomogeneous Poisson random field modeling strategy to characterize nanoparticle dispersion status of nanocomposite polymer, which quantitatively represents the nanomaterial quality presented through image data. The model parameters are estimated through the Bayesian MCMC technique to overcome the challenge of limited amount of accessible data due to the time consuming sampling schemes. The second application is to calibrate the engineering-driven force models of laser-assisted micro milling (LAMM) process statistically, which facilitates a systematic understanding and optimization of targeted processes. In Chapter 4, the force prediction interval has been derived by incorporating the variability in the runout parameters as well as the variability in the measured cutting forces. The experimental results indicate that the model predicts the cutting force profile with good accuracy using a 95% confidence interval. To conclude, this dissertation is the research drawing attention to model enhancement, which has considerable impacts on modeling, design, and optimization of various processes and systems. The fundamental methodologies of model enhancement are developed and furth

Chang, Chia-Jung

75

The Carousel Model of Leisure Behavior.  

ERIC Educational Resources Information Center

|Students' understanding of leisure behavior models may be enhanced when the model is presented graphically as a carousel. Leisure behavior is influenced by a multitude of factors, each of which is represented by a part of the carousel. (IAH)|

Pestle, Karin H.; And Others

1989-01-01

76

Quasi-One-Dimensional Modeling of Pulse Detonation Rocket Engines.  

National Technical Information Service (NTIS)

This viewgraph presentation provides information on the engine cycle of a pulse detonation rocket engine (PDRE), models for optimizing the performance of a PDRE, and the performance of PDREs in comparison to Solid State Rocket Engines (SSREs).

C. I. Morris

2003-01-01

77

Engineering Structurally Configurable Models with Model Transformation.  

National Technical Information Service (NTIS)

Complex configurable models of embedded software systems are hard to design and maintain, especially when model structures are variable and the number of allowable configurations is unlimited. We employ model transformation as an underlying technique to c...

T. H. Feng

2008-01-01

78

An EHF telecommunication system engineering model  

NASA Astrophysics Data System (ADS)

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

Allen, Kenneth C.

1987-11-01

79

Modeling and Dynamic Simulation of IC Engine Driven Permanent Magnet Generator Using Matlab\\/Simulink for Hybrid Tracked Vehicle  

Microsoft Academic Search

A simple dynamic model is needed to study the dynamic behavior of IC engine driven permanent magnet generator, which is used in hybrid tracked vehicle. The simple mathematical model for the typical engine is developed using look-up table obtained from actual test bed results and physical equations. Permanent magnet generator model is developed by dq equivalent circuit model approach for

U. Shanmuganathan; R. Govarthanan; A. Muthumailvaganan; A. Imayakumar

2006-01-01

80

Modeling the Engineering Information Professional.  

ERIC Educational Resources Information Center

Proposes a model for educating information professionals based on three requirements that underlie all information service: academic preparation in digital librarianship; education and practice to cultivate change management and interpersonal skills; and a practicum to develop technological perspective and provide a future orientation. Builds on…

Holland, Maurita Peterson

1998-01-01

81

Modelling of Genetically Engineered Microorganisms Introduction in Closed Artificial Microcosms  

NASA Astrophysics Data System (ADS)

The possibility of introducing genetically engineered microorganisms (GEM) into simple biotic cycles of laboratory water microcosms was investigated. The survival of the recombinant strain Escherichia coli Z905 (Apr, Lux+) in microcosms depends on the type of model ecosystems. During the absence of algae blooming in the model ecosystem, the part of plasmid-containing cells E. coli decreased fast, and the structure of the plasmid was also modified. In conditions of algae blooming (Ankistrodesmus sp.) an almost total maintenance of plasmid-containing cells was observed in E.coli population. A mathematics model of GEM's behavior in water ecosystems with different level of complexity has been formulated. Mechanisms causing the difference in luminescent exhibition of different species are discussed, and attempts are made to forecast the GEM's behavior in water ecosystems.

Pechurkin, N. S.; Brilkov, A. V.; Ganusov, V. V.; Kargatova, T. V.; Maksimova, E. E.; Popova, L. Yu.

1999-01-01

82

Model-Based Security Engineering for Real  

Microsoft Academic Search

We give an overview over a soundly based secure software en- gineering methodology and associated tool-support developed over the last few years under the name of Model-based Security Engineering (MBSE). We focus in particular on applications in industry. The difficulty of designing security mechanisms correctly has motivated very successful research using mathematical concepts and tools to ensure correct de- sign

Jan Jürjens

2006-01-01

83

LPV MODELING OF A TURBOFAN ENGINE  

Microsoft Academic Search

This article describes the application of quasi-LPV modeling techniques to an industrial military turbofan engine simulator developed by Snecma Moteurs, the French aerospace propulsion company. Two approaches are used, classical Jacobian linearization and velocity based linearization. First, we present briey the theoretical aspects of both linearizations. Second, we describe practical implications and limitations. Finally, we present the application of those

Luc Reberga; Didier Henrion

84

Genetically engineered mouse models of neurodegenerative diseases  

Microsoft Academic Search

Recent research has significantly advanced our understanding of the molecular mechanisms of neurodegenerative diseases, including Alzheimer's disease (AD) and motor neuron disease. Here we emphasize the use of genetically engineered mouse models that are instrumental for understanding why AD is a neuronal disease, and for validating attractive therapeutic targets. In motor neuron diseases, Cu\\/Zn superoxide dismutase and survival motor neuron

Huaibin Cai; David R. Borchelt; Donald L. Price; Philip C. Wong

2002-01-01

85

Chromosome-Engineered Mouse Models  

Microsoft Academic Search

Chromosome rearrangements cause genomic disorders and cancer in human. Region-specific low-copy repeats (LCRs) can mediate\\u000a nonallelic homologous recombination (NAHR) that results in chromosome rearrangements. Using the Cre-loxP site-specific recombination\\u000a system, chromosome rearrangements that cause genomic disorders and cancer can be recapitulated in the mouse. Technology advancements\\u000a in mouse genetics, such as recombineering, will undoubtedly facilitate modeling genetic changes associated with

Pentao Liu

86

Sharing Research Models: Using Software Engineering Practices for Facilitation  

PubMed Central

Increasingly, researchers are turning to computational models to understand the interplay of important variables on systems’ behaviors. Although researchers may develop models that meet the needs of their investigation, application limitations—such as nonintuitive user interface features and data input specifications—may limit the sharing of these tools with other research groups. By removing these barriers, other research groups that perform related work can leverage these work products to expedite their own investigations. The use of software engineering practices can enable managed application production and shared research artifacts among multiple research groups by promoting consistent models, reducing redundant effort, encouraging rigorous peer review, and facilitating research collaborations that are supported by a common toolset. This report discusses three established software engineering practices— the iterative software development process, object-oriented methodology, and Unified Modeling Language—and the applicability of these practices to computational model development. Our efforts to modify the MIDAS TranStat application to make it more user-friendly are presented as an example of how computational models that are based on research and developed using software engineering practices can benefit a broader audience of researchers.

Bryant, Stephanie P.; Solano, Eric; Cantor, Susanna; Cooley, Philip C.; Wagener, Diane K.

2011-01-01

87

A modified LPV modeling technique for turbofan engine control system  

Microsoft Academic Search

A modified LPV (Linear Parameter Varying) modeling technique for nonlinear system was put forward and is applied in a turbofan engine model and control analysis. First, a quasi-LPV model of a turbofan engine is designed at various engine operating points using linearized models and the scheduling variable is the fan speed. Then, according to the feedback method, the quasi-LPV model

Li Shu-qing; Zhang Sheng-xiu

2010-01-01

88

Model-based adaptive observers for intake leakage detection in diesel engines  

Microsoft Academic Search

This paper studies the problem of diesel engine diagnosis by means of model-based adaptive observers. The problem is motivated by the needs of guarantee high-performance engine behavior and in particular to respect the environmentally-based legislative regulations. The complexity of the intake systems of this type of engine makes this task particularly arduous and requires to constantly monitor and diagnose the

Riccardo Ceccarelli; Carlos Canudas-de-Wit; Philippe Moulin; Antonio Sciarretta

2009-01-01

89

Microfluidic cell culture models for tissue engineering.  

PubMed

Microfluidic systems have emerged as revolutionary new platform technologies for a range of applications, from consumer products such as inkjet printer cartridges to lab-on-a-chip diagnostic systems. Recent developments have opened the door to a new set of opportunities for microfluidic systems, in the field of tissue and organ engineering. Advances in the design of physiologically relevant structures and networks, fabrication processes for biomaterials suitable for in vivo use, and techniques for scaling towards large, three-dimensional constructs, are converging towards therapeutic applications of microfluidic technologies in engineering complex tissues and organs. These advances herald a new generation of microfluidics-based approaches designed for specific tissue and organ applications, incorporating microvascular networks, structures for transport and filtration, and a three-dimensional microenvironment suitable for supporting phenotypic cell behavior, tissue function, and implantation and host integration. PMID:21723720

Inamdar, Niraj K; Borenstein, Jeffrey T

2011-06-30

90

Automatic generation of software behavioral models  

Microsoft Academic Search

Dynamic analysis of software systems produces behavioral models that are useful for analysis, verification and testing. The main techniques for extracting models of functional behavior generate either models of constraints on data, usually in the form of Boolean expressions, or models of interactions between components, usually in the form of finite state machines. Both data and interaction models are useful

Davide Lorenzoli; Leonardo Mariani; Mauro Pezzè

2008-01-01

91

A model base for software engineering  

Microsoft Academic Search

: This paper presents atutorial on Model-Based Software Engineering(MBSE) as a systematic approach for softwarereuse. The use of models in MBSE differs fromreuse approaches based on libraries which donot define how the components are structured,how they interoperate, and how they arecombined to deliver a given functionality.MBSE offers an approach for systematic reuseby defining the required capabilities of a classof applications,

Shalom Cohen

1994-01-01

92

Biomass reburning - Modeling/engineering studies  

SciTech Connect

This project is designed to develop engineering and modeling tools for a family of NO{sub x} control technologies utilizing biomass as a reburning fuel. During the eleventh reporting period (April 1--June 30, 2000), EER and NETL R&D group continued to work on Tasks 2, 3, 4, and 5. This report includes results from Task 3 physical modeling of the introduction of biomass reburning in a working coal-fired utility boiler.

Sheldon, M.; Marquez, A.; Zamansky, V.

2000-07-27

93

Research Models in Developmental Behavioral Toxicology.  

ERIC Educational Resources Information Center

Developmental models currently used by child behavioral toxicologists and teratologists are inadequate to address current issues in these fields. Both child behavioral teratology and toxicology scientifically study the impact of exposure to toxic agents on behavior development: teratology focuses on prenatal exposure and postnatal behavior

Dietrich, Kim N.; Pearson, Douglas T.

94

Research Models in Developmental Behavioral Toxicology.  

ERIC Educational Resources Information Center

|Developmental models currently used by child behavioral toxicologists and teratologists are inadequate to address current issues in these fields. Both child behavioral teratology and toxicology scientifically study the impact of exposure to toxic agents on behavior development: teratology focuses on prenatal exposure and postnatal behavior

Dietrich, Kim N.; Pearson, Douglas T.

95

Cavitation modeling and diesel engine cylinder liners  

NASA Astrophysics Data System (ADS)

A common occurrence of cavitation damage is the waterside pitting of a wet sleeve liner in a diesel engine. The automotive industry utilizes an ultrasonic test of 20 kHz according to ASTM standards to quantify the effectiveness of engine coolant additives to prevent damage. However, recent tests indicate a mismatch between the ultrasonic test results and actual engine test runs. The focus of this study is to generate numerical models of bubble dynamics using already published literature. In most of the published papers higher-range frequencies (ultrasonic >15 kHz) are used. It is useful to explore the results of lower excitation frequencies as the vibrating frequencies of a diesel engine liner are between 500-9000 Hz. A Rayleigh-Plesset equation, nonlinear in nature, is used to plot the relation between bubble radius and time. Plots of the numerical solution from MATLAB are compared with plots published in the literature. Results from when the frequency of excitation is changed to the liner wall frequency and the fluid properties are changed to approximate engine conditions will be presented. Future work will examine the energy released by the bubble collapse and its correlation with erosion measured as mass change in a standard test button.

Chandekar, Gautam; Pardue, Sally

2003-10-01

96

Preliminary Results from a Four-Working Space, Double-Acting Piston, Stirling Engine Controls Model.  

National Technical Information Service (NTIS)

A four-working space, double-acting piston, Stirling engine simulation is being developed for controls studies. The development method is to construct two simulations, one for detailed fluid behavior, and a second model with simple fluid behavior but cont...

C. J. Daniele C. F. Lorenzo

1980-01-01

97

Modeling of a resonant heat engine  

NASA Astrophysics Data System (ADS)

A resonant heat engine in which the piston assembly is replaced by a sealed elastic cavity is modeled and analyzed. A nondimensional lumped-parameter model is derived and used to investigate the factors that control the performance of the engine. The thermal efficiency predicted by the model agrees with that predicted from the relation for the Otto cycle based on compression ratio. The predictions show that for a fixed mechanical load, increasing the heat input results in increased efficiency. The output power and power density are shown to depend on the loading for a given heat input. The loading condition for maximum output power is different from that required for maximum power density.

Preetham, B. S.; Anderson, M.; Richards, C.

2012-12-01

98

Tools for model-based security engineering: models vs. code  

Microsoft Academic Search

We present tools to support model-based security engineer- ing on both the model and the code level. In the approach supported by these tools, one firstly specifies the security- critical part of the system (e.g. a crypto protocol) using the UML security extension UMLsec. The models are automat- ically verified for security properties using automated the- orem provers. These are

Jan Jürjens; Yijun Yu

2007-01-01

99

LINEARIZATION AND IDENTIFICATION OF AIRCRAFT TURBOFAN ENGINE MODELS  

Microsoft Academic Search

Experiments are carried out to derive linearized models of aircraft turbofan engine dynamics from standard engine simulators used in industry, the ultimate objective being low complexity gain-scheduled control design. First, standard linearization techniques are applied on the OBIDICOTE model, a commercial aircraft engine model developed within a European project. Second, identification algorithms are applied on the model of a military

Didier Henrion; Luc Reberga; Jacques Bernussou; Florian Vary

100

FUZZY MODELLING AND CONTROL OF MARINE DIESEL ENGINE PROCESS  

Microsoft Academic Search

The paper gives an introduction of knowledge modelling techniques i.e. fuzzy models suitable for diesel engine diagnosis and control. Two examples are illustrated for engine faulty condition diagnosis and two simulated examples are given for fuzzy control of diesel engine process: 1. diesel oil viscosity control (Mamdani model used) and 2. shaft speed control (T-S model used). É incomplete and

Radovan Antonic

101

Modeling lahar behavior and hazards  

USGS Publications Warehouse

Lahars are highly mobile mixtures of water and sediment of volcanic origin that are capable of traveling tens to > 100 km at speeds exceeding tens of km hr-1. Such flows are among the most serious ground-based hazards at many volcanoes because of their sudden onset, rapid advance rates, long runout distances, high energy, ability to transport large volumes of material, and tendency to flow along existing river channels where populations and infrastructure are commonly concentrated. They can grow in volume and peak discharge through erosion and incorporation of external sediment and/or water, inundate broad areas, and leave deposits many meters thick. Furthermore, lahars can recur for many years to decades after an initial volcanic eruption, as fresh pyroclastic material is eroded and redeposited during rainfall events, resulting in a spatially and temporally evolving hazard. Improving understanding of the behavior of these complex, gravitationally driven, multi-phase flows is key to mitigating the threat to communities at lahar-prone volcanoes. However, their complexity and evolving nature pose significant challenges to developing the models of flow behavior required for delineating their hazards and hazard zones.

Manville, Vernon; Major, Jon J.; Fagents, Sarah A.

2013-01-01

102

Analysis of fuel and combustion behavior during cold starting of SI gasoline engine  

Microsoft Academic Search

In order to reduce hydrocarbon emission from spark ignition engines, it is important not only to improve catalyst conversion efficiency but also to reduce directly engine-out hydrocarbon emissions during cold starting and warming-up processes. This paper quantitatively analyzes the fuel behavior during the cold starting process of a modern production engine. Using a specially designed analytical method, cycle-by-cycle behavior of

Fumiaki Hattori; Keiso Takeda; Takehisa Yaegashi; Akinori Harada

1997-01-01

103

Surrogate Model Development for Fuels for Advanced Combustion Engines  

SciTech Connect

The fuels used in internal-combustion engines are complex mixtures of a multitude of different types of hydrocarbon species. Attempting numerical simulations of combustion of real fuels with all of the hydrocarbon species included is highly unrealistic. Thus, a surrogate model approach is generally adopted, which involves choosing a few representative hydrocarbon species whose overall behavior mimics the characteristics of the target fuel. The present study proposes surrogate models for the nine fuels for advanced combustion engines (FACE) that have been developed for studying low-emission, high-efficiency advanced diesel engine concepts. The surrogate compositions for the fuels are arrived at by simulating their distillation profiles to within a maximum absolute error of 4% using a discrete multi-component (DMC) fuel model that has been incorporated in the multi-dimensional computational fluid dynamics (CFD) code, KIVA-ERC-CHEMKIN. The simulated surrogate compositions cover the range and measured concentrations of the various hydrocarbon classes present in the fuels. The fidelity of the surrogate fuel models is judged on the basis of matching their specific gravity, lower heating value, hydrogen/carbon (H/C) ratio, cetane number, and cetane index with the measured data for all nine FACE fuels.

Anand, Krishnasamy [University of Wisconsin, Madison; Ra, youngchul [University of Wisconsin, Madison; Reitz, Rolf [University of Wisconsin; Bunting, Bruce G [ORNL

2011-01-01

104

Future Modeling Needs in Pulse Detonation Rocket Engine Design.  

National Technical Information Service (NTIS)

This paper presents a performance model rocket engine design that takes advantage of pulse detonation to generate thrust. The contents include: 1) Introduction to the Pulse Detonation Rocket Engine (PDRE); 2) PDRE modeling issues and options; 3) Discussio...

B. Meade D. Talley D. Mueller D. Tew M. Guidos D. Seymour

2001-01-01

105

A Search Engine for 3D Models  

Microsoft Academic Search

As the number of 3D models available on the Web grows, there is an increasing need for a search engine to help people find them. Unfortunately, traditional text-based search techniques are not always effective for 3D data. In this paper, we investigate new shape-based search methods. The key challenges are to develop query methods simple enough for novice users and

Thomas Funkhouser; Patrick Min; Misha Kazhdan; Joyce Chen; Alex Halderman; David Dobkin; David Jacobs

2002-01-01

106

A search engine for 3D models  

Microsoft Academic Search

As the number of 3D models available on the Web grows, there is an increasing need for a search engine to help people find them. Unfortunately, traditional text-based search techniques are not always effective for 3D data. In this article, we investigate new shape-based search methods. The key challenges are to develop query methods simple enough for novice users and

Thomas A. Funkhouser; Patrick Min; Michael M. Kazhdan; Joyce Chen; Alex Halderman; David P. Dobkin; David Pokrass Jacobs

2003-01-01

107

Animal Models for Bone Tissue Engineering Purposes  

Microsoft Academic Search

To assess the efficacy of engineered tissues, it is necessary to have (1) appropriate large animal models that mimic the clinical\\u000a setting and (2) relevant methods of monitoring the biofuntionality of these tissues. However, developing these tissue constructs\\u000a is a step-by-step process in which numerous variables such as scaffold design, source of stem cells and mode of growth factor\\u000a application

Véronique Viateau; Delphine Logeart-Avramoglou; Geneviève Guillemin; Hervé Petite

108

BIOMASS REBURNING - MODELING/ENGINEERING STUDIES  

SciTech Connect

This project is designed to develop engineering and modeling tools for a family of NO{sub x}control technologies utilizing biomass as a reburning fuel. During the eighth reporting period (July 1--September 26, 1999), Antares Group Inc, under contract to Niagara Mohawk Power Corporation, evaluated the economic feasibility of biomass reburning options for Dunkirk Station. This report includes summary of the findings; complete information will be submitted in the next Quarterly Report.

Vladimir Zamansky; Chris Lindsey

1999-10-29

109

AISI\\/DOE Advanced Process Control Program Vol. 3 of 6: MICROSTRUCTURAL ENGINEERING IN HOT-STRIP MILLS Part 2 of 2: Constitutive Behavior Modeling of Steels Under Hot-Rolling Conditions  

Microsoft Academic Search

This report describes the development of models for predicting (1) constitutive behaviors and (2) mechanical properties of hot-rolled steels as functions of chemical composition, microstructural features, and processing variables. The study includes the following eight steels: A36, DQSK, HSLA-V, HSLA-Nb, HSLA-50\\/Ti-Nb, and two interstitial-free (IF) grades. These developed models have been integrated into the Hot-Strip Mill Model (HSMM), which simulates

Yi-Wen Cheng; Patrick Purtscher

1999-01-01

110

Comparison of Free-Piston Stirling Engine Model Predictions with RE1000 Engine Test Data.  

National Technical Information Service (NTIS)

Predictions of a free-piston Stirling engine model are compared with RE1000 engine test data taken at NASA-Lewis Research Center. The model validation and the engine testing are being done under a joint interagency agreement between the Department of Ener...

R. C. Tew

1984-01-01

111

Tailoring the software engineering Institute's (SEI) Capability Maturity Model (CMM) to a software sustaining engineering organization  

Microsoft Academic Search

The Software Engineering Institute's Softwares Process Maturity Model was developed to provide a basis for assessing an organization's ability to perform software engineering activities. It also provides a guide for improving an organization's software engineering capability. The maturity model was designed on the basis of concepts associated with developing new, large, complex systems. This has led to difficulties in applying

D. W. Drew

1992-01-01

112

Modelling the Design Process in Engineering and in Architecture  

Microsoft Academic Search

Models of the design process in engineering seem to have converged upon a consensus represented, for example, by the German VDI model. However, after starting from common origins, models of the design process in architecture have diverged from the engineering consensus, in response to criticisms from both theorists and practitioners. There now appear to be significant differences between the engineering

NIGEL CROSS; NORBERT ROOZENBURG

1992-01-01

113

The future of computational modelling in reaction engineering.  

PubMed

In this paper, we outline the future of modelling in reaction engineering. Specifically, we use the example of particulate emission formation in internal combustion engines to demonstrate what modelling can achieve at present, and to illustrate the ultimately inevitable steps that need to be taken in order to create a new generation of engineering models. PMID:20603373

Kraft, Markus; Mosbach, Sebastian

2010-08-13

114

Modeling of an internal combustion engine for control analysis  

Microsoft Academic Search

Recent activity in nonthermodynamic modeling of automotive internal combustion engines with spark ignition, which are inherently nonlinear, is reviewed. A fundamental nonlinear model of the engine is presented, and a linear control-oriented model is derived from the nonlinear process. Techniques for experimental verification are examined, and a practical linear engine example incorporating multirate sampling is illustrated

Jeffrey A. Cook; Barry K. Powell

1988-01-01

115

Changing Behavior Through Modeling And Consultation  

ERIC Educational Resources Information Center

This study attempted to determine whether (a) modeling, (b) modeling with behavioral consultation with teachers, (c) a control, and (d) a placebo have differential effects on on-task behavior, attitudes toward school and grade point averages of off-task fifth and sixth grade pupils. Support was provided for the continued use of modeling and…

Randolph, Daniel Lee; Saba, Robert G.

1973-01-01

116

Friction model of a marine diesel engine piston assembly  

Microsoft Academic Search

In modern marine diesel engines, power output and in-cylinder firing pressures are constantly increasing, leading to higher friction in engine components and especially in the piston assembly. A good understanding of the friction contributions of the various engine components is needed, if mechanical efficiency is to be improved. A friction model for the engine piston assembly has been developed and

George A. Livanos; Nikolaos P. Kyrtatos

2007-01-01

117

SEISMIC MODELING ENGINES PHASE 1 FINAL REPORT  

SciTech Connect

Seismic modeling is a core component of petroleum exploration and production today. Potential applications include modeling the influence of dip on anisotropic migration; source/receiver placement in deviated-well three-dimensional surveys for vertical seismic profiling (VSP); and the generation of realistic data sets for testing contractor-supplied migration algorithms or for interpreting AVO (amplitude variation with offset) responses. This project was designed to extend the use of a finite-difference modeling package, developed at Lawrence Berkeley Laboratories, to the advanced applications needed by industry. The approach included a realistic, easy-to-use 2-D modeling package for the desktop of the practicing geophysicist. The feasibility of providing a wide-ranging set of seismic modeling engines was fully demonstrated in Phase I. The technical focus was on adding variable gridding in both the horizontal and vertical directions, incorporating attenuation, improving absorbing boundary conditions and adding the optional coefficient finite difference methods.

BRUCE P. MARION

2006-02-09

118

BIOMASS REBURNING - MODELING/ENGINEERING STUDIES  

SciTech Connect

This project is designed to develop engineering and modeling tools for a family of NO{sub x} control technologies utilizing biomass as a reburning fuel. The forth reporting period (July 1 - September 30) included ongoing kinetic modeling of the reburning process while firing biomass. Modeling of biomass reburning concentrated on description of biomass performance at different reburning heat inputs. Reburning fuel was assumed to undergo rapid breakdown to produce various gaseous products. Modeling shows that the efficiency of biomass is affected by its composition. The kinetic model agrees with experimental data for a wide range of initial conditions and thus can be used for process optimization. Experimental data on biomass reburning are included in Appendix 2.

NONE

1998-10-20

119

BIOMASS REBURNING - MODELING/ENGINEERING STUDIES  

SciTech Connect

This project is designed to develop engineering and modeling tools for a family of NO{sub x} control technologies utilizing biomass as a reburning fuel. During the ninth reporting period (September 27--December 31, 1999), EER prepared a paper Kinetic Model of Biomass Reburning and submitted it for publication and presentation at the 28th Symposium (International) on Combustion, University of Edinburgh, Scotland, July 30--August 4, 2000. Antares Group Inc, under contract to Niagara Mohawk Power Corporation, evaluated the economic feasibility of biomass reburning options for Dunkirk Station. A preliminary report is included in this quarterly report.

Vladimir Zamansky; Chris Lindsey; Vitali Lissianski

2000-01-28

120

A maintenance model for clinical engineering.  

PubMed

The numbers presented here for an equipment maintenance model are derived from a mix of soft data and intuition based on experience. They relate best to university hospitals in the 250-400-bed range. They relate better to numbers of devices than number of beds. In summary, they are: 1. Ideal technician workload = 400 to 550 devices. 2. Average technician productivity or ;;hands-on'' maintenance time = 75%. 3. Average dollar value per device = $2,000. 4. Annual in-house maintenance ratio = 5% to 7% of value plus parts in excess of $200/item. 5. Effective rate per hour = $35 to $45/hr (depending upon region and labor costs in that region). 6. In-house maintenance costs should be less than outside costs. However, the in-house department should be aware of cost-effective outside options and employ them as appropriate. 7. Appropriate resources. 250 sq ft/technician, $20,000 capital equipment/technician, and $15 to $25/device in supplies. 8. Clinical engineers. One engineer to start the service and one engineer for each three additional technicians added. 9. Clerical support. One clerical FTE for a minimum 3 technician department, and one additional clerical FTE for each additional 1.5 FTE clinical engineers or each additional 5 FTE technicians. 10. Annual maintenance = 2.5 hr/device. (When clinical devices are distinguished from nonclinical devices, averages are 3 hr/clinical device and 2 hr/nonclinical device.) As clinical engineers, BMETs, and their departments gather experience to support or modify these numbers, I encourage them to share their findings in an experience pool available to all. PMID:19493765

Johnston, G I

1985-01-01

121

Behavior Change and the Ecological Model.  

ERIC Educational Resources Information Center

Application of the ecological model to children with behavioral problems focuses on the degree to which behavior matches the demands, expectations, or levels of tolerance of individuals in the environment. Such individuals as well as the child may need to change their behaviors. (DB)

Evans, Susan S.; Evans, William H.

1987-01-01

122

A circumplex model for maternal behavior  

Microsoft Academic Search

The purpose  is to demonstrate the generality of a social interaction conceptualization of maternal behavior by ordering the intercorrelation matrices of three sets of data on maternal behavior. When ordered both with factor analysis and with Guttman's circumplex model, similar two-dimensional organizations of maternal behavior concepts were found for the three sets of data.\\

Earl S. Schaefer

1959-01-01

123

A Model of Household Grocery Shopping Behavior  

Microsoft Academic Search

The shopping trip to the grocery store is one of the most basic elements of consumer behavior. The authors seek to provide an understanding of the factors that account for variations in shopping behavior across households. They present a model of shopping behavior that assumes that households seek to minimize the travel cost associated with shopping and the cost of

Kapil Bawa; Avijit Ghosh

1999-01-01

124

Implicit test generation for behavioral VHDL models  

Microsoft Academic Search

This paper proposes a behavioral-level test patterngeneration algorithm for behavioral VHDL descriptions.The proposed approach is based on the comparison betweenthe implicit description of the fault-free behaviorand the faulty behavior, obtained through a new behavioralfault model. The paper will experimentally showthat the test patterns generated at the behavioral levelprovide a very high stuck-at fault coverage when appliedto different gate-level implementations of

Fabrizio Ferrandi; Franco Fummi; Donatella Sciuto

1998-01-01

125

BIOMASS REBURNING - MODELING/ENGINEERING STUDIES  

SciTech Connect

This project is designed to develop engineering and modeling tools for a family of NO{sub x} control technologies utilizing biomass as a reburning fuel. The sixth reporting period (January 1--March 31, 1999) included CFD modeling and assessment of available experimental and modeling data on biomass reburning. Experimental and modeling data obtained within scope of this and Phase II SBIR USDA projects were reviewed and analyzed. This work was necessary to summarize available data and to make decision about additional efforts that are necessary for successful completion of the DOE FETC project. These efforts resulted in preparation of the paper entitled ''Kinetic Study of Biomass Reburning'' which was presented at the 1999 Joint Meeting of the United States Sections of the Combustion Institute. The paper is included in Attachment A.

Vitali V. Lissianski; Vladimir M. Zamansky

1999-04-29

126

Biomass Reburning - Modeling/Engineering Studies  

SciTech Connect

This project is designed to develop engineering and modeling tools for a family of NO{sub x} control technologies utilizing biomass as a reburning fuel. The second reporting period (January 1- March 31) included kinetic modeling of the reburning process while firing natural gas and biomass. Modeling was done with a kinetic mechanism that combined reactions relevant to reburning from GRI-Mech 2.11 with SNCR reactions. Experimental data obtained in a 1 MMBtu/h Boiler Simulator Facility (BSF) for reburning with natural gas and biomass were modeled using the ODF kinetic code. System was treated as a series of four one-dimensional reactors. Modeling of natural gas reburning qualitatively agrees with experimental data for a wide range of initial conditions. Modeling of furniture waste reburning does not qualitatively match experimental data due to a number of model simplifications. Future work will concentrate on improving the basic reburning model to give quantitative agreement with experiments and on search for better representation of biomass composition in kinetic modeling. Experimental data on biomass reburning are included in Appendix 3. These data were obtained during the reporting period in the scope of a coordinated program funded by the U.S. Department of Agriculture.

Peter M. Maly; Vitali V. Lissianski; Vladimir M. Zamansky

1998-04-30

127

Towards a computer aided simulation model engineering (CASME) environment  

Microsoft Academic Search

There is increasing focus on the model development aspect of systems simulation, termed “Model Engineering”. Current software development tools consist primarily of CASE tools with simulation extensions or simulation tools with model-building extensions. The need for a Computer-Aided Simulation Model Engineering (CASME) environment is identified and discussed. In particular, a CASME environment should support a model building process based on

Joel J. Luna

1993-01-01

128

A Simplified Analysis on a Pulse Detonation Engine Model  

Microsoft Academic Search

The performance of pulse detonation engines was analytically estimated by using a simple model. A pulse detonation engine was modeled as a straight tube. One end of the tube was closed and the other was open, and a detonation wave was ignited at the closed end. One cycle of the pulse-detonation-engine operation was divided into three phases: combustion, exhaust, and

Takuma Endo; Toshi Fujiwara

2005-01-01

129

Design model generation for reverse engineering using multi-sensors  

Microsoft Academic Search

Reverse engineering is the process of creating a design model and a manufacturing database for an existing part or prototype. The applications of reverse engineering are in redesigning of existing parts\\/tools or prototype parts where the CAD model of the part is not available. Reverse engineering, for the most part, is performed as an interactive process where the designer identifies

Saeid Motavalli; Vithaya Suharitdamrong; Abdalla Alrashdan

1998-01-01

130

The systems engineering capability maturity model: where to start?  

Microsoft Academic Search

The systems engineering capability maturity model is a tool designed to help companies measure and improve their system engineering processes. The architecture of the model is designed to provide the user with a lot of flexibility, and to not be overly prescriptive with regards to how companies should structure their improvement plans. However, the result is that the systems engineering

K. Cusick

1997-01-01

131

Application of Product Model for Engineering Process Definition  

Microsoft Academic Search

Integration of all engineering related information in a single complex product model is one of the main purposes in computer system based engineering activities. Because engineering process highly depends on product development and application projects, its definition was first realized in product modeling environments at the application of product data management (PDM) systems. However, this administrative solution could not be

Aniko Szak´l

2011-01-01

132

Modeling Driver Behavior in a Cognitive Architecture  

Microsoft Academic Search

Objective: This paper explores the development of a rigorous computational model of driver behavior in a cognitive architecture--a computational framework with underlying psychological theories that incorporate basic properties and limitations of the human system. Background: Computational modeling has emerged as a powerful tool for studying the complex task of driving, allowing researchers to simulate driver behavior and explore the parameters

Dario D. Salvucci

2006-01-01

133

Modelling Retail Customer Behavior at Merrill Lynch  

Microsoft Academic Search

A two state Markov chain model is used to describe and forecast the over time behavior of the best retail customers at Merrill Lynch. This model has 4 behaviorally meaningful parameters which capture the effect of recently being a prime customer, the differing average commissions generated across customers and the exiting of some of these customers from the Merrill Lynch

Donald G. Morrison; Richard D. H. Chen; Sandra L. Karpis; Kathryn E. A. Britney

1982-01-01

134

Preliminary results from a four-working space, double-acting piston, Stirling engine controls model  

SciTech Connect

A four-working space, double-acting piston, Stirling engine simulation is being developed for controls studies. The development method is to construct two simulations, one for detailed fluid behavior, and a second model with simple fluid behavior but containing the four working space aspects and engine inertias, validate these models separately, then upgrade the four-working space model by incorporating the detailed fluid behavior model for all four working spaces. The single working space (SWS) model contains the detailed fluid dynamics. It has seven control volumes in which continuity, energy, and pressure loss effects are simulated. Comparison of the SWS model with experimental data shows reasonable agreement in net power versus speed characteristics for various mean pressure levels in the working space. The four-working space (FWS) model was built to observe the behavior of the whole engine. The drive dynamics and vehicle inertia effects are simulated. To reduce calculation time, only three volumes are used in each working space and the gas temperatures are fixed (no energy equation). Comparison of the FWS model predicted power with experimental data shows reasonable agreement. Since all four-working spaces are simulated, the unique capabilities of the model are exercised to look at working fluid supply transients, short circuit transients, and piston ring leakage effects. The FWS model has been upgraded by using the detailed SWS model for each of the four working spaces. Currently the detailed FWS model is being reworked to reduce the amount of calculation time per cycle.

Daniele, C.J.; Lorenzo, C.F.

1980-01-01

135

Statistical Validation of Engineering and Scientific Models: Background  

SciTech Connect

A tutorial is presented discussing the basic issues associated with propagation of uncertainty analysis and statistical validation of engineering and scientific models. The propagation of uncertainty tutorial illustrates the use of the sensitivity method and the Monte Carlo method to evaluate the uncertainty in predictions for linear and nonlinear models. Four example applications are presented; a linear model, a model for the behavior of a damped spring-mass system, a transient thermal conduction model, and a nonlinear transient convective-diffusive model based on Burger's equation. Correlated and uncorrelated model input parameters are considered. The model validation tutorial builds on the material presented in the propagation of uncertainty tutoriaI and uses the damp spring-mass system as the example application. The validation tutorial illustrates several concepts associated with the application of statistical inference to test model predictions against experimental observations. Several validation methods are presented including error band based, multivariate, sum of squares of residuals, and optimization methods. After completion of the tutorial, a survey of statistical model validation literature is presented and recommendations for future work are made.

Hills, Richard G.; Trucano, Timothy G.

1999-05-01

136

Comparison of Free-Piston Stirling Engine Model Predictions with RE1000 Engine Test Data.  

National Technical Information Service (NTIS)

Predictions of a free-piston Stirling engine model are compared with RE1000 Sunpower engine test data taken at NASA-Lewis Research Center. A kinematic code was upgraded to permit simulation of free-piston engine performance; it was further upgraded and mo...

R. C. Tew

1984-01-01

137

Model for the Main Engine Problem Based Training for Marine Engineering Students  

Microsoft Academic Search

Successful education of marine engineering students could be provided with combination of theoretical classes, training on simulators and real training onboard training vessels. The most effective practical training is correction of chance failures after they occur within the real engine room. This paper is dealing with technological model for detection and correction of the main engine chance failures from the

Zeljko Kurtela; Vedran Jelavic

138

Visualization of oil behavior in a small 4-cycle engine with electrical motoring by neutron radiography  

NASA Astrophysics Data System (ADS)

Neutron radiography is suitable for the visualization of liquid behavior in a metallic machine. Observation of oil behavior in a small 4-cycle engine on operating was carried out by using the neutron radiography facility at JRR-3 in JAEA. The engine was not fired but operated by an electrical motor. Movies were taken by a neutron image intensifier with a color CCD camera of 8-bit resolution, 30 frames/s and 640×480 pixels developed by Toshiba Corp. The engine was placed on a turn table and was rotated, so the movie could be taken from any angle. Numbers of revolution of the engine were changed from 260 to 1200 rpm. Visualized images of the mechanism and the oil behavior in the engine were obtained.

Nakamura, M.; Sugimoto, K.; Asano, H.; Murakawa, H.; Takenaka, N.; Mochiki, K.

2009-06-01

139

Performance optimization of Jatropha biodiesel engine model using Taguchi approach  

Microsoft Academic Search

This paper proposes a methodology for thermodynamic model analysis of Jatropha biodiesel engine in combination with Taguchi’s optimization approach to determine the optimum engine design and operating parameters. A thermodynamic model based on two-zone Weibe’s heat release function has been employed to simulate the Jatropha biodiesel engine performance. Among the important engine design and operating parameters 10 critical parameters were

T. Ganapathy; K. Murugesan; R. P. Gakkhar

2009-01-01

140

Work in progress - the WSU model for engineering mathematics education  

Microsoft Academic Search

This paper summarizes progress to date on the WSU model for engineering mathematics education, an NSF funded curriculum reform initiative at Wright State University. The WSU model seeks to increase student retention, motivation and success in engineering through application-driven, just-in-time engineering math instruction. The WSU approach involves the development of a novel freshman-level engineering mathematics course EGR 101, as well

Nathan Klingbeil; Richard Mercer; Kuldip Rattan; Michael Raymer; David Reynolds

2005-01-01

141

Towards Usable User Studies: Assessing the Information Behavior of Scientists and Engineers.  

National Technical Information Service (NTIS)

The report describes a secondary analysis of data describing the information-related attitudes and behaviors of scientists and engineers in terms of their organizational and situational attributes. The database represented the responses of some 560 scient...

C. K. Mick G. N. Lindsey D. Callahan F. Spielberg

1979-01-01

142

International Education for Engineers: A Working Model  

Microsoft Academic Search

An overview is provided of the need for a portion of science and engineering graduates to have language and cultural backgrounds for international involvement. The nature and educa tional background of engineering students, which have changed measurably in recent years, are reviewed. The experimental interna tional engineering programs developed in the College of Engineering at the University of Illinois are

Howard L. Wakeland

1990-01-01

143

PARAMETRIC MODEL OF AN AEROSPIKE ROCKET ENGINE  

Microsoft Academic Search

A suite of computer codes was assembled to simulate the performance of an aerospike engine and to generate the engine input for the Program to Optimize Simulated Trajectories. First an engine simulator module was developed that predicts the aerospike engine performance for a given mixture ratio, power level, thrust vectoring level, and altitude. This module was then used to rapidly

J. J. Korte

2000-01-01

144

Operating strategy for a hydrogen engine for improved drive-cycle efficiency and emissions behavior  

Microsoft Academic Search

Due to their advanced state of development and almost immediate availability, hydrogen internal combustion engines could act as a bridging technology toward a wide-spread hydrogen infrastructure. Extensive research, development and steady-state testing of hydrogen internal combustion engines has been conducted to improve efficiency, emissions behavior and performance. This paper summarizes the steady-state test results of the supercharged hydrogen-powered four-cylinder engine

Thomas Wallner; Henning Lohse-Busch; Neeraj Shidore

2009-01-01

145

Knowledge-Based Search Engine for Specific 3D Models  

Microsoft Academic Search

\\u000a A search engine is implemented to support querying specific 3D models – digitized Indian pottery on Internet for scientists.\\u000a The engine is knowledge-based. I.e. not only shape information but also shape feature information (knowledge) of 3D models\\u000a can be retrieved via the engine. Shape information of 3D models is collected from Lasers Scanner and\\/or geometric modeling\\u000a techniques. Feature information is

Dezhi Liu; Anshuman Razdan

2004-01-01

146

Hybrid rocket engine, theoretical model and experiment  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to build a theoretical model for the hybrid rocket engine/motor and to validate it using experimental results. The work approaches the main problems of the hybrid motor: the scalability, the stability/controllability of the operating parameters and the increasing of the solid fuel regression rate. At first, we focus on theoretical models for hybrid rocket motor and compare the results with already available experimental data from various research groups. A primary computation model is presented together with results from a numerical algorithm based on a computational model. We present theoretical predictions for several commercial hybrid rocket motors, having different scales and compare them with experimental measurements of those hybrid rocket motors. Next the paper focuses on tribrid rocket motor concept, which by supplementary liquid fuel injection can improve the thrust controllability. A complementary computation model is also presented to estimate regression rate increase of solid fuel doped with oxidizer. Finally, the stability of the hybrid rocket motor is investigated using Liapunov theory. Stability coefficients obtained are dependent on burning parameters while the stability and command matrixes are identified. The paper presents thoroughly the input data of the model, which ensures the reproducibility of the numerical results by independent researchers.

Chelaru, Teodor-Viorel; Mingireanu, Florin

2011-06-01

147

Software process modeling for an educational software engineering simulation game  

Microsoft Academic Search

SimSE is an educational software engineering simulation game that uses a unique software process modeling ap- proach. This approach combines both predictive and prescriptive aspects to support the creation of dynamic, interactive, graphical models for software engineering process education. This paper describes the different constructs in a SimSE process model, introduces the associated model builder tool, describes how we built

Emily Oh Navarro; André Van Der Hoek

2005-01-01

148

Mouse Chromosome Engineering for Modeling Human Disease  

PubMed Central

Chromosomal rearrangements occur frequently in humans and can be disease-associated or phenotypically neutral. Recent technological advances have led to the discovery of copy-number changes previously undetected by cytogenetic techniques. To understand the genetic consequences of such genomic changes, these mutations need to be modeled in experimentally tractable systems. The mouse is an excellent organism for this analysis because of its biological and genetic similarity to humans, and the ease with which its genome can be manipulated. Through chromosome engineering, defined rearrangements can be introduced into the mouse genome. The resulting mouse models are leading to a better understanding of the molecular and cellular basis of dosage alterations in human disease phenotypes, in turn opening new diagnostic and therapeutic opportunities.

van der Weyden, Louise; Bradley, Allan

2008-01-01

149

Modeling Dad: Animal models of paternal behavior  

Microsoft Academic Search

In humans, paternal behaviors have a strong influence on the emotional and social development of children. Fathers, more frequently than mothers, leave the family nucleus, and\\/or become abusive, leading to offspring that are more likely to grow under stressful conditions and greater susceptibility to abnormal health and social outcomes. Literature on parental behaviors, human or animal, has primarily focused on

Amanda C. Kentner; Alfonso Abizaid; Catherine Bielajew

2010-01-01

150

The Software Engineering of Domain-Specific Modeling Languages: A Survey Through Examples  

Microsoft Academic Search

This paper presents the fundamental concepts of model-based design to the broader software engineering community. We examine model-based design from the perspective of domain-specific modeling languages (DSMLs). DSMLs capture the structure behavioral characteristics and abstractions of complex problem domains. Model transformations defined between language syntaxes serve as high-level specifications of domain-specific compilers. Additionally transformations are used to change abstraction levels.

Ethan K. Jackson

151

Aggressive behavior model in schizophrenic patients.  

PubMed

This study aimed to determine the optimal model for explaining the aggressive behavior of schizophrenic patients in relation to certain behavioral variables including anger, schizophrenic symptoms, and cognitive function. Schizophrenic patients were evaluated with the Modified Overt Aggression Scale (MOAS) for aggressive behaviors, with irritability and resentment; with the Buss-Durkee Hostility Inventory (BDHI) for anger; with the Wisconsin Card Sorting Test (WCST) and the Grooved Pegboard Test for cognitive function; and with the Positive and Negative Syndrome Scale (PANSS) for schizophrenic symptoms. The structural equation model (SEM) in AMOS 7 for the score of "aggressive behavior in the last week" in the MOAS, was used for statistical analysis. For the SEM, two factors (irritability and resentment) were selected from the BDHI and constituted the anger construct. Through factor analysis, two factors (executive function and motor function) were selected from the cognitive function measurements to constitute the cognitive function construct. Two factors (positive and negative symptoms) in the PANSS constituted the symptom construct. The best model for aggressive behavior (MOAS) with three constructs revealed a direct, significant path of "anger emotion to aggressive behavior". This result suggests that the aggressive behavior of schizophrenic patients is directly related to anger. Schizophrenic symptoms and cognitive function were indirectly related to aggressive behavior through the relationship between the emotion of anger and aggressive behavior. PMID:19359046

Song, Hyunjoo; Min, Sung Kil

2009-04-08

152

A graduate-level chemical engineering practice model in Thailand  

Microsoft Academic Search

The Chemical Engineering Practice School (ChEPS) at King Mongkut's University of Technology Thonburi (KMUTT) in Bangkok is a two-year international curriculum modeled after Massachusetts Institute of Technology's David H. Koch School of Chemical Engineering Practice. The aim of this intensive Master's program is to produce professional chemical engineers with strong fundamentals, practical experience, and a good command of English. The

H. M. Ku; S. Thonglek; S. Bhumiratana

153

UNDERSTANDING RAMPs THROUGH GENETICALLY ENGINEERED MOUSE MODELS  

PubMed Central

The family of Receptor Activity Modifying Proteins (RAMPs) consists of three members, RAMP1, 2 and 3, which are each encoded by a separate gene and have diverse spatiotemporal expression patterns. Biochemical and pharmacological studies in cultured cells have shown that RAMPs can modulate several aspects of G receptor (GPCR) signaling, including receptor trafficking, ligand binding affinity, second messenger signaling and receptor desensitization. Moreover, these studies have shown that RAMPs can interact with several GPCRs other than the canonical calcitonin receptor-like receptor (CLR), with which they were first identified. Given these expanding roles for RAMPs, it becomes interesting to question how these biochemical and pharmacological properties bear significance in normal or disease physiology. To this end, several gene targeted knockout and transgenic models have been generated and characterized in recent years. Fortunately, they have each supported important roles for RAMPs during embryonic development and adulthood. This chapter provides a comprehensive overview of the most recent findings from gene targeted knockout mouse models and transgenic over-expression models, and gives special consideration to how comparative phenotyping approaches and conditional deletion strategies can be highly beneficial. In the future, these genetically engineered mouse models will provide both insights and tools for the exploitation of RAMP-based therapies for the treatment of human diseases.

Kadmiel, Mahita; Fritz-Six, Kimberly L.; Caron, Kathleen M.

2013-01-01

154

Biomass Reburning: Modeling/Engineering Studies  

SciTech Connect

Reburning is a mature fuel staging NO{sub x} control technology which has been successfully demonstrated at full scale by Energy and Environmental Research Corporation (EER) and others on numerous occasions. Based on chemical kinetic modeling and experimental combustion studies, EER is currently developing novel concepts to improve the efficiency of the basic gas reburning process and to utilize various renewable and waste fuels for NO{sub x} control. This project is designed to develop engineering and modeling tools for a family of NO{sub x} control technologies utilizing biomass as a reburning fuel. Basic and advanced biomass reburning have the potential to achieve 60-90+% NO{sub x} control in coal fired boilers at a significantly lower cost than SCR. The scope of work includes modeling studies (kinetic, CFD, and physical modeling), experimental evaluation of slagging and fouling associated with biomass reburning, and economic study of biomass handling requirements. Project participants include: EER, FETC R and D group, Niagara Mohawk Power Corporation and Antares, Inc. Most of the combustion experiments on development of biomass reburning technologies are being conducted in the scope of coordinated SBIR program funded by USDA. The first reporting period (October 1--December 31, 1997) included preparation of project management plan and organization of project kick-off meeting at DOE FETC. The quarterly report briefly describes the management plan and presents basic information about the kick-off meeting.

Vladimir M. Zamansky

1998-01-20

155

Dynamic engine modeling through linear programming Support Vector Regression  

Microsoft Academic Search

In this paper, we develop a dynamic model for an internal combustion engine using Support Vector Regression (SVR). In particular, a linear programming SVR (LP-SVR) approach is investigated. The computational advantages and generalization capability of the LP-SVR dynamic engine model are illustrated through a case study, where a model is developed for an L4 gasoline engine. Simulation results are reported

Zhao Lu; Jing Sun; Dongkyoung Lee; Ken Butts

2009-01-01

156

Hybrid Model of the Gasoline Engine for Misfire Detection  

Microsoft Academic Search

This paper proposes a novel hybrid model for an internal combustion engine, with the power generated due to combustion as the input and the crankshaft speed fluctuations as the output. The individual cylinders of the engine are considered as subsystems for which a nonlinear model, based on the physical principles, is derived. The proposed model is linearized at an oper-

Muddassar Abbas Rizvi; Aamer Iqbal Bhatti; Qarab Raza Butt

2011-01-01

157

Modelling of combustion process in the gas test engine  

Microsoft Academic Search

Paper presents results of modelling gas engine thermal cycle using AVL FIRE and KIVA 3V software. There are described three combustion models used in above mentioned software. Comparison of modelling results of thermal cycle of IC engine is presented in the paper.

Arkadiusz Jamrozik; Wojciech Tutak

2010-01-01

158

Integrating Surface Modeling into the Engineering Design Graphics Curriculum  

ERIC Educational Resources Information Center

|It has been suggested there is a knowledge base that surrounds the use of 3D modeling within the engineering design process and correspondingly within engineering design graphics education. While solid modeling receives a great deal of attention and discussion relative to curriculum efforts, and rightly so, surface modeling is an equally viable…

Hartman, Nathan W.

2006-01-01

159

Diagrammatic Models in the Engineering Sciences  

Microsoft Academic Search

This paper is concerned with scientific reasoning in the engineering sciences. Engineering sciences aim at explaining, predicting and describing physical phenomena occurring in technological devices. The focus of this paper is on mathematical description. These mathematical descriptions are important to computer-aided engineering or design programs (CAE and CAD). In the first part of this paper it is explained why a

MIEKE BOON

2005-01-01

160

Engineering Glass Passivation Layers -Model Results  

SciTech Connect

The immobilization of radioactive waste into glass waste forms is a baseline process of nuclear waste management not only in the United States, but worldwide. The rate of radionuclide release from these glasses is a critical measure of the quality of the waste form. Over long-term tests and using extrapolations of ancient analogues, it has been shown that well designed glasses exhibit a dissolution rate that quickly decreases to a slow residual rate for the lifetime of the glass. The mechanistic cause of this decreased corrosion rate is a subject of debate, with one of the major theories suggesting that the decrease is caused by the formation of corrosion products in such a manner as to present a diffusion barrier on the surface of the glass. Although there is much evidence of this type of mechanism, there has been no attempt to engineer the effect to maximize the passivating qualities of the corrosion products. This study represents the first attempt to engineer the creation of passivating phases on the surface of glasses. Our approach utilizes interactions between the dissolving glass and elements from the disposal environment to create impermeable capping layers. By drawing from other corrosion studies in areas where passivation layers have been successfully engineered to protect the bulk material, we present here a report on mineral phases that are likely have a morphological tendency to encrust the surface of the glass. Our modeling has focused on using the AFCI glass system in a carbonate, sulfate, and phosphate rich environment. We evaluate the minerals predicted to form to determine the likelihood of the formation of a protective layer on the surface of the glass. We have also modeled individual ions in solutions vs. pH and the addition of aluminum and silicon. These results allow us to understand the pH and ion concentration dependence of mineral formation. We have determined that iron minerals are likely to form a complete incrustation layer and we plan to look more closely at Vivianite [Fe3(PO4)2-8(H2O)] and Siderite [FeCO3] in the next stage of the project.

Skorski, Daniel C.; Ryan, Joseph V.; Strachan, Denis M.; Lepry, William C.

2011-08-08

161

The Working Set Model for Program Behavior.  

National Technical Information Service (NTIS)

Probably the most basic reason behind the absence of a general treatment of resource allocation in modern computer systems is an adequate model for program behavior. In this paper a new model, the 'working set model,' is developed. The working set of page...

P. J. Denning

1967-01-01

162

The working set model for program behavior  

Microsoft Academic Search

Probably the most basic reason behind the absence of a general treatment of resource allocation in modern computer systems is an adequate model for program behavior. In this paper a new model is developed, the “working set model”, which enables us to decide which information is in use by a running program and which is not. Such knowledge is vital

Peter J. Denning

1967-01-01

163

The working set model for program behavior  

Microsoft Academic Search

Probably the most basic reason behind the absence of a general treatment of resource allocation in modern computer systems is an adequate model for program behavior. In this paper a new model, the “working set model,” is developed. The working set of pages associated with a process, defined to be the collection of its most recently used pages, provides knowledge

Peter J. Denning

1983-01-01

164

Hierarchical test generation for VHDL behavioral models  

Microsoft Academic Search

In this method, the VHDL model to be tested is represented by its process model graph (PMG). Test sets for individual processes of the model are precomputed and stored in the design library. The Hierarchical Behavioral Test Generator (HBTG) algorithm accepts the PMG and the precomputed tests as inputs, from which it hierarchically constructs a test sequence that tests the

Sanat R. Rao; Bi-Yu Pan; James R. Armstrong

1993-01-01

165

Modeling Architectural Patterns' Behavior Using Architectural Primitives  

Microsoft Academic Search

Architectural patterns have an impact on both the structure and the behavior of a system at the architecture design level.\\u000a However, it is challenging to model patterns’ behavior in a systematic way because modeling languages do not provide the appropriate\\u000a abstractions and because each pattern addresses a whole solution space comprised of potentially infinite solution variants.\\u000a In this paper, we

Ahmad Waqas Kamal

2008-01-01

166

Modeling Abstract Behavior: A Dynamic Logic Approach  

Microsoft Academic Search

Modeling abstract behavior is essential for intelligent agents under incomplete and uncertain environments. In this paper,\\u000a we extend Propositional Dynamic Logic (PDL) to Propositional Abstract Dynamic Logic (PADL) for modeling abstract behavior\\u000a in two aspects. On the one hand, we treat the task of finding a plan to achieve a certain formula as an abstract action. On\\u000a the other hand,

Yi Zhou; Yan Zhang

2009-01-01

167

Cognitive Architectures for Modeling Driver Behavior  

Microsoft Academic Search

Abstract The Problem. The driving task involves a host of relevant cognitive, perceptual, and motor abilities. Cognitive architectures—frameworks,for modeling human,cognition and behavior—have evolved to integrate known,theories of human cognition into unified theories that account for a wide range of cognitive phenomena. Role of Driving Simulators. Models of driver behavior based on cognitive architectures can be linked into driving simulators to

Dario D. Salvucci

168

A systemic model of doping behavior.  

PubMed

Human behavior occurs within a system, and as such, so do behaviors in performance-related domains (e.g., athletics, academics). Doping is a performance enhancement behavior that can be problematic because of the negative physical and psychological effects associated with the use of some substances and the common argument that doping is unfair. However, doping continues and may be increasing. Because a firm theoretical or empirical understanding of doping does not exist, this article proposes a conceptual, comprehensive, and innovative systemic model of doping behavior. The model is built from relevant empiricism supporting the idea that contemporary doping behavior is a function of systemic transactions between historical doping practices, the present environment, current antidoping interventions, one's genetic makeup, developmental milestones, social factors, and epigenetics. PMID:21834401

Johnson, Michael B

2011-01-01

169

Modeling and prediction of human behavior.  

PubMed

We propose that many human behaviors can be accurately described as a set of dynamic modes (e.g., Kalman filters) sequenced together by a Markov chain. We then use these dynamic Markov models to recognize human behaviors from sensory data and to predict human behaviors over a few seconds time. To test the power of this modeling approach, we report an experiment in which we were able to achieve 95% accuracy at predicting automobile drivers' subsequent actions from their initial preparatory movements. PMID:9950731

Pentland, A; Liu, A

1999-01-01

170

Long Term Oxidation of Model and Engineering TiAl Alloys.  

National Technical Information Service (NTIS)

The purpose of this research was to characterize the oxidation behavior of several model (TiAl, TiAl-Nb, TiAl-Cr, TiAl-Cr-Nb) and engineering alloys (XD, K5, Alloy 7, WMS) after long-term isothermal exposure ((approx)7000 h) at 704 C, and after shorter ti...

I. E. Locci

2001-01-01

171

Long Term Oxidation of Model and Engineering TiAl Alloys.  

National Technical Information Service (NTIS)

The purpose of this research was to characterize the oxidation behavior of several model (TiAl, TiAl-Nb, TiAl-Cr, TiAl-Cr-Nb) and engineering alloys (XD, K5, Alloy 7, WMS) after long-term isothermal exposure (approximately 7000 h) at 704 C, and after shor...

I. E. Locci

2001-01-01

172

A model-based systems engineering approach to capturing disaster management systems  

Microsoft Academic Search

The purpose of this paper is to initiate the design of a framework for defining and capturing disaster management systems (DMS). Recognizing the management of disasters as complex adaptive systems (CAS), whose performance cannot be improved through the isolated optimization of their constituents, this paper proposes the adoption of model-based systems engineering (MBSE) to capturing the behavior of such systems,

Asli Soyler; Serge Sala-Diakanda

2010-01-01

173

Optimal Replacement of GMC Bus Engines: An Empirical Model of Harold Zurcher  

Microsoft Academic Search

This paper formulates a simple, regenerative, optimal-stopping model of bus-eng ine replacement to describe the behavior of Harold Zurcher, superinte ndent of maintenance at the Madison (Wisconsin) Metropolitan Bus Comp any. Admittedly, few people are likely to take particular interest in Harold Zurcher and bus engine replacement per se. The author focuses on a specific individual and capital good because

John Rust

1987-01-01

174

Modeling immune behavior for experimentalists.  

PubMed

This article outlines the requirements for useful models of biologic systems. Such models should fulfill three conditions: (i) suit the bottom-up data of the living system, not merely adhere to top-down logic; (ii) abet experimentation by stimulating new ideas for novel experiments; and (iii) engage the mind of the experimentalist with understandable, visual representations. Seven characteristics of a useful model are discussed. PMID:17367346

Cohen, Irun R

2007-04-01

175

Hydrologic Behavior of Two Engineered Barriers following Extreme Wetting  

Microsoft Academic Search

buried wastes and contaminated soils. The most serious problems encountered in shallow land burial of wastes Many engineered barriers are expected to function for hundreds are related to water management (Jacobs et al., 1980; of years or longer. Over the course of time, it is likely that some

Indrek Porro

2001-01-01

176

Modelling and Inverse-Modelling: Experiences with O.D.E. Linear Systems in Engineering Courses  

ERIC Educational Resources Information Center

|In engineering careers courses, differential equations are widely used to solve problems concerned with modelling. In particular, ordinary differential equations (O.D.E.) linear systems appear regularly in Chemical Engineering, Food Technology Engineering and Environmental Engineering courses, due to the usefulness in modelling chemical kinetics,…

Martinez-Luaces, Victor

2009-01-01

177

Modeling medulloblastoma with genetically engineered mice.  

PubMed

Medulloblastoma is a malignant tumor that arises in the cerebellum in children, presumably by transformation of granule neuron precursor cells. In vivo models of medulloblastoma in genetically engineered mice have shown that activation of signal transduction pathways that stimulate proliferation and inhibit differentiation of neural progenitor cells during cerebellar development initiate medulloblastoma formation. Activation of the Sonic hedgehog (Shh)/Patched signaling pathway in the postnatal cerebellum is sufficient to induce medulloblastoma in mice. Activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway by insulin-like growth factor-II, inactivation of the p53 tumor suppressor protein, loss of DNA damage repair mechanisms, and ectopic expression of Myc oncoproteins cooperate with Shh/Patched signaling to enhance tumor formation in mice. Ectopic expression of alpha and beta interferons in the developing brain also induces Shh-mediated medulloblastoma formation, suggesting a possible role for antiviral response in the genesis of medulloblastoma. By revealing which cell signaling proteins can initiate medulloblastoma formation, mouse models have enabled investigators to identify molecular targets for designing new therapies. Small-molecule inhibitors of the Shh/Patched and PI3K pathways are potential chemotherapeutic agents for patients with medulloblastoma. PMID:16398471

Fults, Daniel W

2005-11-15

178

Diagrammatic Models in the Engineering Sciences  

Microsoft Academic Search

This paper is concerned with scientific reasoning in the engineering sciences. Engineering sciences aim at explaining, predicting\\u000a and describing physical phenomena occurring in technological devices. The focus of this paper is on mathematical description.\\u000a These mathematical descriptions are important to computer-aided engineering or design programs (CAE and CAD). The first part\\u000a of this paper explains why a traditional view, according

Mieke Boon

2008-01-01

179

Model for the Performance of Airbreathing Pulse-Detonation Engines  

Microsoft Academic Search

An analytical model for predicting the performance of a single-tube air-breathing pulse detonation engine has been developed. The model is based on control volume methods and elementary gas dynamics. The pulse detonation engine considered consists of a steady supersonic inlet, a large plenum, and a straight detonation tube (no exit nozzle). The fllling process is studied in detail through numerical

E. Wintenberger; J. E. Shepherd

2006-01-01

180

Rocketdyne\\/Westinghouse nuclear thermal rocket engine modeling  

Microsoft Academic Search

The topics are presented in viewgraph form and include the following: systems approach needed for nuclear thermal rocket (NTR) design optimization; generic NTR engine power balance codes; rocketdyne nuclear thermal system code; software capabilities; steady state model; NTR engine optimizer code-logic; reactor power calculation logic; sample multi-component configuration; NTR design code output; generic NTR code at Rocketdyne; Rocketdyne NTR model;

James F. Glass

1993-01-01

181

Model-based reasoning: a principled approach for software engineering  

Microsoft Academic Search

The software engineering industry suffers from almost unmanageable complexity both in the prod- ucts it produces and in the processes of production. One of the current shortcomings in the software production process is the weakness of the models used. This paper makes observations on the role of knowledge in engineer- ing and examines the central role of models and simu-

M. H. Lee

2000-01-01

182

Mean Value SI Engine Model for Control Studies  

Microsoft Academic Search

This paper presents a mathematically simple nonlinear three state (three differential equation) dynamic model of an SI engine which has the same steady state accuracy as a typical dynamometer measurement of the engine over its entire speed\\/load operating range (± 2.0%). The model's accuracy for large, fast transients is of the same order in the same operating region. Because the

Elbert Hendricks; Spencer Sorenson

1990-01-01

183

ADMIRE: an adaptive data model for meta search engines  

Microsoft Academic Search

Considering the diversity among search engines, efficient integration of them is an important but difficult job. It is essential to provide a data model that can provide a detailed description of the query capabilities of heterogeneous search engines. By means of this model, the meta-searcher can map users' queries into specific sources more accurately, and it can achieve good precision

Lieming Huang; Matthias Hemmje; Erich J. Neuhold

2000-01-01

184

NTP system simulation and detailed nuclear engine modeling  

Microsoft Academic Search

The topics are presented in viewgraph form and include the following: nuclear thermal propulsion (NTP) & detailed nuclear engine modeling; modeling and engineering simulation of nuclear thermal rocket systems; nuclear thermal rocket simulation system; INSPI-NTVR core axial flow profiles; INSPI-NTRV core axial flow profiles; specific impulse vs. chamber pressure; turbine pressure ratio vs. chamber pressure; NERVA core axial flow profiles;

Samim Anghaie

1993-01-01

185

Models of iodine behavior in reactor containments  

SciTech Connect

Models are developed for many phenomena of interest concerning iodine behavior in reactor containments during severe accidents. Processes include speciation in both gas and liquid phases, reactions with surfaces, airborne aerosols, and other materials, and gas-liquid interface behavior. Although some models are largely empirical formulations, every effort has been made to construct mechanistic and rigorous descriptions of relevant chemical processes. All are based on actual experimental data generated at the Oak Ridge National Laboratory (ORNL) or elsewhere, and, hence, considerable data evaluation and parameter estimation are contained in this study. No application or encoding is attempted, but each model is stated in terms of rate processes, with the intention of allowing mechanistic simulation. Taken together, this collection of models represents a best estimate iodine behavior and transport in reactor accidents.

Weber, C.F.; Beahm, E.C.; Kress, T.S.

1992-10-01

186

Measurement and modeling of soil electromagnetic behavior  

Microsoft Academic Search

The paper presents procedures to measure and model soil electromagnetic parameters, as a function of frequency, adequate for frequency domain and transient studies of soil behavior and its effect in grounding. Such procedures take into account the problems related to field measurements, the need of a physical validation, and the great diversity of soil characteristics. The physical model, with a

Carlos Portela

1999-01-01

187

Modeling behavioral considerations related to information security.  

SciTech Connect

The authors present experimental and simulation results of an outcome-based learning model for the identification of threats to security systems. This model integrates judgment, decision-making, and learning theories to provide a unified framework for the behavioral study of upcoming threats.

Martinez-Moyano, I. J.; Conrad, S. H.; Andersen, D. F. (Decision and Information Sciences); (SNL); (Univ. at Albany)

2011-01-01

188

Modeling Individual Behaviors in Crowd Simulation  

Microsoft Academic Search

This paper presents a model for studying the impact of individual agents characteristics in emergent groups, on the evacuation efficiency as a result of local interactions. We used the physically based model of crowd simulation proposed by Helbing (6) and generalized it in order to deal with different individualities for agent and group behaviors. In addition, we present a framework

Adriana Braun; Soraia Raupp Musse; Luiz Paulo Luna De Oliveira; Bardo E. J. Bodmann

2003-01-01

189

Numerical Modeling of Pulse Detonation Rocket Engine Gasdynamics And Performance.  

National Technical Information Service (NTIS)

Pulse detonation rocket engines (PDREs) offer potential performance improvements over conventional designs, but represent a challenging modeling task. A quasi-1-D, finite-rate chemistry computational fluid dynamics model for PDREs is described and impleme...

C. I. Morris

2004-01-01

190

Engineering Economic Model for Fish Protein Concentration Processes.  

National Technical Information Service (NTIS)

A process engineering economic model for fish protein concentration processes has been developed. The model predicts the construction and operating costs for fish meal plants and for plants producing fish protein concentrate (FPC) by: isopropyl alcohol ex...

J. W. Gentry K. K. Almenas L. C. Durilla M. B. Hale R. C. Ernst

1972-01-01

191

Trichotillomania: A comprehensive behavioral model  

Microsoft Academic Search

As our knowledge of chronic hair pulling as neither rare nor benign has increased, so has the need for a comprehensive framework to guide our conceptualization of this disorder for both research and clinical work. Such a model is presented which incorporates 1.(a) the varied antecedents that both cue the impulse to pull and facilitate pulling,2.(b) the wide array of

Ruth Goldfinger Golomb

1997-01-01

192

A technology empowerment model for engineering work  

Microsoft Academic Search

Seeking to enhance the use of information technology for problem solving\\/decision support efforts and innovation in engineering work, management has sought to empower engineers by investing in increasingly powerful software capabilities and peer support networks to facilitate an experiential process of working and learning. Based on the concept of psychological empowerment from the management literature, the researchers propose a technology

William J. Doll; Xiaodong Deng

2010-01-01

193

Persistence of Effects of Live Behavioral, Televised Behavioral, and Live Verbal Models on Resistance to Deviation  

ERIC Educational Resources Information Center

|Live behavioral and televised behavioral models were the most effective, and live verbal models were the least effective. The effects of the deviant models were more stable over time than the effects of the conforming models. (Authors)|

Wolf, Thomas M.; Cheyne, J. Allan

1972-01-01

194

Extensibility in Model-Based Business Process Engines  

NASA Astrophysics Data System (ADS)

An organization’s ability to embrace change, greatly depends on systems that support their operation. Specifically, process engines might facilitate or hinder changes, depending on their flexibility, their extensibility and the changes required: current workflow engine characteristics create difficulties in organizations that need to incorporate some types of modifications. In this paper we present Cumbia, an extensible MDE platform to support the development of flexible and extensible process engines. In a Cumbia process, models represent participating concerns (control, resources, etc.), which are described with concern-specific languages. Cumbia models are executed in a coordinated way, using extensible engines specialized for each concern.

Sánchez, Mario; Jiménez, Camilo; Villalobos, Jorge; Deridder, Dirk

195

Axial thrust behavior in LOX-pump of rocket engine  

Microsoft Academic Search

The LOX pump of the first stage of the H-2 rocket, the next generation of large launch vehicle in Japan, has shown fairly good axial thrust performance. However, the behavior of the axial thrust is not well known because of the complicated mechanism of the thrust-balancing device. In order to elucidate the flow characteristic of the complicated thrust balancing device

Junichi Kurokawa; Kenjiro Kamijo; Takashi Shimura

1994-01-01

196

Modeling aggressive driver behavior at unsignalized intersections.  

PubMed

The processing of vehicles at unsignalized intersections is a complex and highly interactive process, whereby each driver makes individual decisions about when, where, and how to complete the required maneuver, subject to his perceptions of distances, velocities, and own car's performance. Typically, the performance of priority-unsignalized intersections has been modeled with probabilistic approaches that consider the distribution of gaps in the major-traffic stream and their acceptance by the drivers of minor street vehicles based on the driver's "critical gap". This paper investigates the aggressive behavior of minor street vehicles at intersections that are priority-unsignalized but operate with little respect of control measures. The objective is to formulate a behavioral model that predicts the probability that a driver performs an aggressive maneuver as a function of a set of driver and traffic attributes. Parameters that were tested and modeled include driver characteristics (gender and age), car characteristics (performance and model year), and traffic attributes (number of rejected gaps, total waiting time at head of queue, and major-traffic speed). Binary probit models are developed and tested, based on a collected data set from an unsignalized intersection in the city of Beirut, to determine which of the studied variables are statistically significant in determining the aggressiveness of a specific driver. Primary conclusions reveal that age, car performance, and average speed on the major road are the major determinants of aggressive behavior. Another striking conclusion is that the total waiting time of the driver while waiting for an acceptable gap is of little significance in incurring the "forcing" behavior. The obtained model is incorporated in a simple simulation framework that reflects driver behavior and traffic stream interactions in estimating delay and conflict measures at unsignalized intersections. The simulation results were then compared against real world observations, representing an important step in validating the model of aggressive driver behavior at unsignalized intersections. PMID:17157794

Kaysi, Isam A; Abbany, Ali S

2006-12-08

197

Modeling mechanical behavior of epoxy-shape memory polymers  

NASA Astrophysics Data System (ADS)

Smart materials and structures is an international frontier field in current development of engineering and science. Representative of soft smart materials include Electroactive polymers (EAPs) and Shape Memory Polymers (SMPs), etc..As a new kind of smart deformation material, SMPs have a wide range of applications in the field of smart material and structures due to their controllable shape memory effects. Deformation mechanism of SMP material is the basis of its applications. This paper proposed an useful thermoviscoelastic constitutive model by considering thermal expansion, structure relaxation and viscoelastic properties of Epoxy-SMP material. To verify the applicability of the model, various experiments such as isothermal uniaxial tensile tests were carried out and then be simulated. The results showed that the constitutive model could nicely predict mechanical behavior of Epoxy-SMP, the proposed constitutive model is useful for the design of SMPs structures.

Chen, Jianguo; Liu, Liwu; Fei, Fan; Wang, Yixing; Liu, Yanju; Leng, Jinsong

2013-04-01

198

Modeling behavioral design patterns of concurrent objects  

Microsoft Academic Search

Object-oriented software development practices are being rapidly adopted within increasingly complex systems, including reactive, real-time and concurrent system applications. While data modeling is performed very well under current object-oriented development practices, behavioral modeling necessary to capture critical information in real-time, reactive, and concurrent systems is often lacking. Addressing this deficiency, we offer an approach for modeling and analyzing concurrent object-oriented

Robert G. Pettit IV; Hassan Gomaa

2006-01-01

199

Mathematical models of brand choice behavior  

Microsoft Academic Search

A critical review of recent developments in the single-stage and two-stage models of brand choice behavior is provided. The rich and complex history of development of choice models is organized via the two fundamental principles that drive most of the literature on single-stage choice models. The first principle of utility maximization has its roots in economic theory and it led

Ajay K. Manrai

1995-01-01

200

A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES  

SciTech Connect

The work summarized here comprises the concluding effort of a multi-year project, funded by the U.S. Department of Energy, Office of Vehicle Technologies. It supports the development of a better understanding of advanced diesel engine designs in which enhanced power density, energy efficiency, and emissions control place increasing demands upon the durability of engine materials. Many kinds of metallic alloys are used in engines depending on the operating stresses, temperatures, and chemical environments. Exhaust valves, for example, are subjected to high temperatures and repetitive surface contacts that place demands on durability and frictional characteristics of the materials. Valves must continue to seal the combustion chamber properly for thousands of hours of cyclic engine operation and under varying operating conditions. It was the focus of this effort to understand the wear processes in the valve-seat area and to develop a model for the surface deformation and wear of that important interface. An annotated bibliography is provided to illustrate efforts to understand valve wear and to investigate the factors of engine operation that affect its severity and physical manifestation. The project for which this modeling effort was the final task, involved construction of a high-temperature repetitive impact test system as well as basic tribology studies of the combined processes of mechanical wear plus oxidation at elevated temperatures. Several publications resulted from this work, and are cited in this report. The materials selected for the experimental work were high-performance alloys based on nickel and cobalt. In some cases, engine-tested exhaust valves were made available for wear analysis and to ensure that the modes of surface damage produced in experiments were simulative of service. New, production-grade exhaust valves were also used to prepare test specimens for experimental work along with the other alloy samples. Wear analysis of valves and seats run for hundreds of hours in heavy-duty diesels provided insights into the kinds of complexity that the contact conditions in engines can produce, and suggested the physical basis for the current approach to modeling. The model presented here involves four terms, two representing the valve response and two for its mating seat material. The model's structure assumes that wear that takes place under a complex combination of plastic deformation, tangential shear, and oxidation. Tribolayers form, are removed, and may reform. Layer formation affects the friction forces in the interface, and in turn, the energy available to do work on the materials to cause wear. To provide friction data for the model at various temperatures, sliding contact experiments were conducted from 22 to 850 C in a pin-on-disk apparatus at ORNL. In order to account for the behavior of different materials and engine designs, parameters in all four terms of the model can be adjusted to account for wear-in and incubation periods before the dominant wear processes evolve to their steady-state rates. For example, the deformation rate is assumed to be maximum during the early stages of operation, and then, due to material work-hardening and the increase in nominal contact area (which reduces the load per unit area), decreases to a lower rate at long times. Conversely, the rate of abrasion increases with time or number of cycles due to the build-up of oxides and tribo-layers between contact surfaces. The competition between deformation and abrasion results in complex, non-linear behavior of material loss per cycle of operation. Furthermore, these factors are affected by valve design features, such as the angle of incline of the valve seat. Several modeling scenarios are presented to demonstrate how the wear profile versus number of cycles changes in response to: (a) different relative abrasion rates of the seat and valve materials, (b) the friction coefficient as a function of temperature, (c) the relative deformation contribution of valve and seat materials, and (d) an interruption in the dominant we

Blau, Peter Julian [ORNL

2009-11-01

201

Parameterised Mixing Time Model for Diesel Engines Simulation  

Microsoft Academic Search

A parameterised mixing time model is presented. It accounts for changes in time of the mixing intensity in an engine cylinder. The model has been used within the stochastic reactor based modelling framework to simulate Diesel combustion conditions. The obtained results were compared with those from the single parameter mixing time model. The investigation revealed that with the parameterised model

M. Pasternak; F. Mauss; H. Bensler

2009-01-01

202

Numerical modeling of hydrogen-fueled internal combustion engines  

Microsoft Academic Search

Major progress was achieved in the last year in advancing the modeling capabilities of hydrogen-fueled engines, both in support of the multi-laboratory project with SNL and LLNL to develop a high-efficiency, low emission powerplant and to provide the engine design tools to industry and research laboratories for hydrogen-fueled engines and stationary power generators. The culmination of efforts on many fronts

N. L. Johnson; A. A. Amsden; T. D. Butler

1996-01-01

203

A diesel engine map model based observer for HEVs  

Microsoft Academic Search

The aim of this study is to introduce an engine-map model-based nonlinear observer for the estimation of unmeasured variables, such as engine torque, emissions, fuel consumption and exhaust for a hybrid army vehicle. A 2.2 liter, 4-cylinder, 85 kW, turbocharged Peugeot diesel engine is taken into consideration for this purpose. The performance of the proposed observer is evaluated via simulations

Metin Gokasan; Seta Bogosyan; Douglas J. Goering

2005-01-01

204

Observing and modeling nonlinear dynamics in an internal combustion engine  

Microsoft Academic Search

We propose a low-dimensional, physically motivated, nonlinear map as a model for cyclic combustion variation in spark-ignited internal combustion engines. A key feature is the interaction between stochastic, small-scale fluctuations in engine parameters and nonlinear deterministic coupling between successive engine cycles. Residual cylinder gas from each cycle alters the in-cylinder fuel-air ratio and thus the combustion efficiency in succeeding cycles.

C. S. Daw; M. B. Kennel; C. E. Finney; F. T. Connolly

1998-01-01

205

Combustion and emissions behavior for ethanol–gasoline blends in a single cylinder engine  

Microsoft Academic Search

This paper investigates the effect of using gasoline–ethanol mid-level blends (0–20% ethanol) on engine performance and exhausts emissions on a single cylinder engine by AVL model 5401, spark ignited and electronically controlled with DOHC. Engine tests were conducted for different lambda values, brake power and brake specific fuel consumption, while exhaust emissions were analyzed for carbon monoxide, unburned hydrocarbons and

I. Schifter; L. Diaz; R. Rodriguez; J. P. Gómez; U. Gonzalez

2011-01-01

206

Modeling and control of a variable valve timing engine  

Microsoft Academic Search

A cylinder-by-cylinder model of an experimental variable valve timing 4-cylinder engine has been developed. The model includes the cylinder and manifold mass, temperature, burned gas residual, and pressure dynamics, including combustion effects, as well as the valve actuator dynamics. The cylinder-by-cylinder model is used to obtain a cycle-averaged mapping between torque at a given engine speed and intake valve timing,

Lawrence Mianzo; Huoi Peng

2000-01-01

207

Stochastic modelling of power reactor fuel behavior  

NASA Astrophysics Data System (ADS)

An understanding of the in-reactor behavior of nuclear fuel is essential to the safe and economic operation of a nuclear power plant. It is no longer possible to achieve this without computer code calculations. A state of art computer code, FRODO, for Fuel ROD Operation, has been developed to model the steady state behavior of fuel pins in a light water reactor and to do sensitivity analysis. FRODO concentrates on the thermal performance, fission product release and pellet-clad interaction and can be used to predict the fuel failure under the prevailing conditions. FRODO incorporates the numerous uncertainties involved in fuel behavior modeling, using statistical methods, to ascertain fuel failures and their causes. Sensitivity of fuel failure to different fuel parameters and reactor conditions can be easily evaluated. FRODO has been used to analyze the sensitivities of fuel failures to coolant flow reductions. It is found that the uncertainties have pronounced effects on conclusions about fuel failures and their causes.

Mirza, Shahid Nawaz

208

Review of aerospace engineering cost modelling: The genetic causal approach  

Microsoft Academic Search

The primary intention of this paper is to review the current state of the art in engineering cost modelling as applied to aerospace. This is a topic of current interest and in addressing the literature, the presented work also sets out some of the recognised definitions of cost that relate to the engineering domain. The paper does not attempt to

R. Curran; S. Raghunathan; M. Price

2004-01-01

209

Enabler 1 and 2 engine system design modeling and comparisons  

NASA Astrophysics Data System (ADS)

Viewgraphs on Enabler 1 and 2 engine system design modeling and comparisons are presented. The objective of this research was to define a near-term solid-core nuclear thermal propulsion (NTP) engine system scaling database. A unified set of performance, weight, and size scaling data are identified and documented. Results should be useful to meet initial mission and concept design study requirements.

Pelaccio, Dennis G.; Scheil, Christine M.

210

Development and testing of diesel engine CFD models  

Microsoft Academic Search

The development and validation of Computational Fluid Dynamic (CFD) models for diesel engine combustion and emissions is described. The complexity of diesel combustion requires simulations with many complex, interacting submodels in order to be successful. The review focuses on the current status of work at the University of Wisconsin Engine Research Center. The research program, which has been ongoing for

R. D. Reitz; C. J. Rutland

1995-01-01

211

Building a narrative based Requirements Engineering mediation model  

Microsoft Academic Search

This paper presents a narrative-based Requirements Engineering (RE) mediation model to help RE practitioners to effectively identify, define, and resolve conflicts of interest, goals, and requirements. With SPI community, there is a common belief that social, human, and organizational issues significantly impact on the effectiveness of the software process improvement in general and requirements engineering process in particularly. Conflicts among

Nan Ma; Tracy Hall; Trevor Barker

212

A Multidisciplinary Model for Teaching Undergraduate Engineering Design.  

ERIC Educational Resources Information Center

|This project was designed to develop a curricular and pedagogical model for teaching multidisciplinary engineering design to senior-level undergraduate students at the Colorado School of Mines. The two-semester course sequence involved students from seven engineering disciplines working in multidisciplinary teams under the direction of…

Miller, Ronald L.; Olds, Barbara M.

213

Marine Diesel Engine Process Modelling and Control Using Advanced Technologies  

Microsoft Academic Search

The paper presents some possibilities of practical use of advanced computing technologies applied to the modelling and control of marine diesel engine. The emphasis is put on two well recognised techniques, fuzzy logic and artificial neural networks. Because of the complexity of diesel propulsion engine working in changeable operating regimes and environmental conditions at sea, it is highly desirable to

R. Antonic; Z. Vukic; O. Kuljaca

2005-01-01

214

Requirements Engineering for Scientific Computing: A Model-Based Approach  

Microsoft Academic Search

Requirements engineering is crucial to the success of software development. However, in many scientific computing projects, traditional requirements engineering practices are ignored. We claim that there is a need for methodologies, which help capturing and managing requirements for these projects, to collaboratively develop scientific software with greater interoperability. We propose a model-based approach to elicit and manage requirements in scientific

Yang Li; Matteo Harutunian; Nitesh Narayan; Bernd Bruegge; Gerrit Buse

2011-01-01

215

Animal models of restricted repetitive behavior in autism  

Microsoft Academic Search

Restricted, repetitive behavior, along with deficits in social reciprocity and communication, is diagnostic of autism. Animal models relevant to this domain generally fall into three classes: repetitive behavior associated with targeted insults to the CNS; repetitive behavior induced by pharmacological agents; and repetitive behavior associated with restricted environments and experience. The extant literature provides potential models of the repetitive behavioral

Mark H. Lewis; Yoko Tanimura; Linda W. Lee; James W. Bodfish

2007-01-01

216

Generating Business Process Models from Object Behavior Models  

Microsoft Academic Search

Object-oriented modeling is an established approach to document information systems. In an object model, a system is captured in terms of object types and associations, state machines and collaboration diagrams, among others. Process modeling on the other hand, provides a different approach whereby behavior is captured in terms of activities, flow dependencies, resources, etc. These two approaches have their relative

Guy Redding; Marlon Dumas; Arthur H. M. Ter Hofstede; Adrian Iordachescu

2008-01-01

217

How Do Engineering Scientists Think? Model-Based Simulation in Biomedical Engineering Research Laboratories  

Microsoft Academic Search

Designing, building, and experimenting with physical simulation models are central problem-solving practices in the engineering sciences. Model-based simulation is an epistemic activity which includes exploration, generation and testing of hypotheses, explanation, and inference. This paper argues that to interpret and understand how these simulation models function in creating knowledge and technologies requires construing problem solving as accomplished by a researcher

Nancy J. Nersessian

2009-01-01

218

Study on Modeling and Simulation of a Flight Simulator Engine System  

Microsoft Academic Search

The accurate aero-engine simulation of the flight simulator is very difficult. To establish the perfect models of aero-engine, the study on modeling method and simulation of turbofan engine system are carried out in this paper. Based on the engine operating principle, control law, logical relation of individual components and vast test data, the engine performance models and function models are

Haiguo Xiong; Qitao Huang; Hongzhou Jiang; Junwei Han

2007-01-01

219

Structural Equation Modeling in Behavioral Research  

Cancer.gov

April 27, 2012 10:00 AM - 11:00 AM + Add to Outlook Calendar Date and Time: Friday, April 27th, 10:00-11:00am, EPS/7107 Lecturer:  Natalia Frishman, MD PhD Candidate Iowa State University Print This Page Structural Equation Modeling in Behavioral Research News

220

Modeling the Dynamic Behavior of Hypermedia Applications  

Microsoft Academic Search

Hypermedia applications can be defined as collections of interactive and multimedia documents that are organized as a hypertext net. The development of hypermedia applications poses specific problems, such as the need for modeling sophisticated navigational structures, interactive behaviors, and harmonic presentations involving the synchronization of contents. Moreover, the increasing popularity of Internet based systems has put stress on the lack

Paloma Díaz; Ignacio Aedo; Fivos Panetsos

2001-01-01

221

AN INTEGRATIVE MODEL OF CORPORATE ENTREPRENEURIAL BEHAVIOR  

Microsoft Academic Search

Abstract Based on extensive literature review and empirical validation this paper aims to develop and test an integrative model of corporate entrepreneurial b ehavior. Indeed, how much do we know about the tactics that corporate entrepreneurs employ to promote entrepreneurial projects? Entrepreneurial behavior is generally defined as th e discovery, evaluation, and exploitation of entrepreneurial opportunities. Still, more investig ation

Olga BELOUSOVA; Benoît GAILLY; Olivier BASSO

222

Machine Learning Approaches for Modeling Spammer Behavior  

Microsoft Academic Search

Spam is commonly known as unsolicited or unwanted email messages in the Internet causing potential threat to Internet Security. Users spend a valuable amount of time deleting spam emails. More importantly, ever increasing spam emails occupy server storage space and consume network bandwidth. Keyword-based spam email filtering strategies will eventually be less successful to model spammer behavior as the spammer

Abdullah Al Mahmud

2010-01-01

223

A Propaganda Model of Business School Behavior  

Microsoft Academic Search

This paper draws examples from strategic management, entrepreneurship, and marketing to indicate that business school academics engage in a range of behaviors that filter reality in ways that promote (or shield) corporate interests. A variation on Hermann and Chomsky's propaganda model is used to explain the apparent self-censorship of business school academics. Five factors are identified that act to de-radicalize

J Jo; Steven Phelan

224

An Empirical Analysis of Strategic Behavior Models  

Microsoft Academic Search

Existing strategic behavior models indicate that the strategic interaction of informed and liquidity traders leads to systematic intraday patterns on stock exchanges. This paper uses a unique database from the Helsinki Stock Exchange, which allows the parties of all trades to be identified so that their transactions can be tracked intra-day and over time. We classify traders as either informed

Carole Comerton-Forde; Michael O'Brien; P. Joakim Westerholm

2007-01-01

225

Audiovisual Behavior Modeling by Combined Feature Spaces  

Microsoft Academic Search

Great interest is recently shown in behavior modeling, especially in public surveillance tasks. In general it is agreed upon the benefits of use of several input cues as audio and video. Yet, synchronization and fusion of these information sources remains the main challenge. We therefore show results for a feature space combination, which allows for overall feature space optimization. Audio

Bjorn Schuller; D. Arsic; G. Rigoll; M. Wimmer; B. Radig

2007-01-01

226

Overview of heat transfer and fluid flow problem areas encountered in stirling engine modeling  

Microsoft Academic Search

NASA Lewis Research Center has been managing Stirling engine development programs for over a decade. In addition to contractual programs, this work has included in-house engine testing and development of engine computer models. Attempts to validate Stirling engine computer models with test data have demonstrated that engine thermodynamic losses need better characterization. Various Stirling engine thermodynamic losses and efforts that

Tew; R. C. Jr

1988-01-01

227

Parental Behavior and Vocational Choice: A Comparison of Counselors and Engineers  

ERIC Educational Resources Information Center

This study compared the perceived parental behavior characteristics of 41 counselors in training and 33 fifth-year engineering students in a test of Roe's vocational choice theory, which suggests dichotomous pattern of vocational choice: "toward persons" or "toward nonpersons" categories that are determined by the nature of early childhood…

Wittmer, Joe; And Others

1974-01-01

228

Modeling of thermo-mechanical and irradiation behavior of mixed oxide fuel for sodium fast reactors  

Microsoft Academic Search

An engineering code to model the irradiation behavior of UO2–PuO2 mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named fuel engineering and structural analysis tool (FEAST-OXIDE). FEAST-OXIDE has several modules working in coupled form with an explicit numerical algorithm. These modules describe: (1) fission gas release and swelling, (2) fuel chemistry and restructuring, (3) temperature

Aydin Karahan; Jacopo Buongiorno

2010-01-01

229

Corrosion behavior of engineering alloys in synthetic wastewater  

NASA Astrophysics Data System (ADS)

The corrosion behavior of 1018, 410, and 800 steels exposed to synthetic wastewater have been studied using linear polarization resistance, cyclic potentiodynamic curves (CPCs), electrochemical noise (EN), and electrochemical impedance spectroscopy (EIS) tests. The conditions were: a biochemical oxygen demand of 776 ppm; a chemical oxygen demand of 1293 ppm; a pH of 8; and a cell temperature of 25 °C. From the CPC and EN results, no localized corrosion was found for the stainless steels. However, small indications of a possible localized corrosion process were detected for the 1018 steel. The EIS results revealed that different corrosion mechanisms occurred in the carbon steel compared with the stainless steels. The results show that the corrosion mechanism strongly depends on the type of steel. Overall, the 1018 steel exhibited the highest corrosion rate, followed by the 410 alloy. The highest corrosion resistance was achieved by the 800 alloy. In addition, scanning electron microscopy analyses were carried out to explain the experimental findings.

Sandoval-Jabalera, R.; Arias-Del Campo, E.; Chacón-Nava, J. G.; Martínez-Villafañe, A.; Malo-Tamayo, J. M.; Mora-Mendoza, J. L.

2006-02-01

230

An analytical model of self-starting thermoacoustic engines  

NASA Astrophysics Data System (ADS)

This paper presents a theoretical model of thermoacoustic engines. It aims for a better physical understanding of the power production of these devices. The main idea that supports the work is that the power output emerges from a thermodynamic cycle. The fluid near the heat exchangers is assumed to follow a thermodynamic cycle such as in a closed chamber of a Stirling reciprocating engine. This analogy between thermoacoustic engines and Stirling reciprocating engines introduces a lumped element in the model as the closed chamber of the Stirling engine. In the analogy, the boundaries of this lumped element are the pistons of the chamber, and the kinematical mechanism of the reciprocating engine is the acoustic process in the pipes. The position of the pistons is fixed by studying the longitudinal heat transfer process and the mass conservation. The set of equations obtained can be solved by using the mathematical limit that represents the actual small movement of the pistons. The result is four linear algebraic equations that can be easily solved in several practical cases. One outcome of this approach is the selection of a few dimensionless design parameters useful for any configuration of the engine. Another outcome is a simplified method of calculating the initial power around a self-starting point of a thermoacoustic engine. Finally, the threshold of several thermoacoustic devices is calculated with the present model and compared with the experimental results reported in the scientific literature.

Benavides, Efrýn Moreno

2006-06-01

231

Engineering complex topological memories from simple Abelian models  

SciTech Connect

In three spatial dimensions, particles are limited to either bosonic or fermionic statistics. Two-dimensional systems, on the other hand, can support anyonic quasiparticles exhibiting richer statistical behaviors. An exciting proposal for quantum computation is to employ anyonic statistics to manipulate information. Since such statistical evolutions depend only on topological characteristics, the resulting computation is intrinsically resilient to errors. The so-called non-Abelian anyons are most promising for quantum computation, but their physical realization may prove to be complex. Abelian anyons, however, are easier to understand theoretically and realize experimentally. Here we show that complex topological memories inspired by non-Abelian anyons can be engineered in Abelian models. We explicitly demonstrate the control procedures for the encoding and manipulation of quantum information in specific lattice models that can be implemented in the laboratory. This bridges the gap between requirements for anyonic quantum computation and the potential of state-of-the-art technology. - Highlights: > A novel quantum memory using Abelian anyons is developed. > This uses an advanced encoding, inspired by non-Abelian anyons. > Errors are suppressed topologically, by means of single spin interactions. > An implementation with current Josephson junction technology is proposed.

Wootton, James R., E-mail: phyjrw@leeds.ac.uk [School of Physics and Astronomy, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom); Lahtinen, Ville [School of Physics and Astronomy, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom); Doucot, Benoit [Laboratoire de Physique Theorique et Hautes Energies, Universite Paris 6 et 7, Paris (France); Pachos, Jiannis K. [School of Physics and Astronomy, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom)

2011-09-15

232

A motivational model for environmentally responsible behavior.  

PubMed

This paper presents a study examining whether self-efficacy and intrinsic motivation are related to environmentally responsible behavior (ERB). The study analysed past environmental behavior, self-regulatory mechanisms (self-efficacy, satisfaction, goals), and intrinsic and extrinsic motivation in relation to ERBs in a sample of 156 university students. Results show that all the motivational variables studied are linked to ERB. The effects of self-efficacy on ERB are mediated by the intrinsic motivation responses of the participants. A theoretical model was created by means of path analysis, revealing the power of motivational variables to predict ERB. Structural equation modeling was used to test and fit the research model. The role of motivational variables is discussed with a view to creating adequate learning contexts and experiences to generate interest and new sensations in which self-efficacy and affective reactions play an important role. PMID:22774439

Tabernero, Carmen; Hernández, Bernardo

2012-07-01

233

Modeling and simulation of dust behaviors behind a moving vehicle  

NASA Astrophysics Data System (ADS)

Simulation of physically realistic complex dust behaviors is a difficult and attractive problem in computer graphics. A fast, interactive and visually convincing model of dust behaviors behind moving vehicles is very useful in computer simulation, training, education, art, advertising, and entertainment. In my dissertation, an experimental interactive system has been implemented for the simulation of dust behaviors behind moving vehicles. The system includes physically-based models, particle systems, rendering engines and graphical user interface (GUI). I have employed several vehicle models including tanks, cars, and jeeps to test and simulate in different scenarios and conditions. Calm weather, winding condition, vehicle turning left or right, and vehicle simulation controlled by users from the GUI are all included. I have also tested the factors which play against the physical behaviors and graphics appearances of the dust particles through GUI or off-line scripts. The simulations are done on a Silicon Graphics Octane station. The animation of dust behaviors is achieved by physically-based modeling and simulation. The flow around a moving vehicle is modeled using computational fluid dynamics (CFD) techniques. I implement a primitive variable and pressure-correction approach to solve the three dimensional incompressible Navier Stokes equations in a volume covering the moving vehicle. An alternating- direction implicit (ADI) method is used for the solution of the momentum equations, with a successive-over- relaxation (SOR) method for the solution of the Poisson pressure equation. Boundary conditions are defined and simplified according to their dynamic properties. The dust particle dynamics is modeled using particle systems, statistics, and procedure modeling techniques. Graphics and real-time simulation techniques, such as dynamics synchronization, motion blur, blending, and clipping have been employed in the rendering to achieve realistic appearing dust behaviors. In addition, I introduce a temporal smoothing technique to eliminate the jagged effect caused by large simulation time. Several algorithms are used to speed up the simulation. For example, pre-calculated tables and display lists are created to replace some of the most commonly used functions, scripts and processes. The performance study shows that both time and space costs of the algorithms are linear in the number of particles in the system. On a Silicon Graphics Octane, three vehicles with 20,000 particles run at 6-8 frames per second on average. This speed does not include the extra calculations of convergence of the numerical integration for fluid dynamics which usually takes about 4-5 minutes to achieve steady state.

Wang, Jingfang

234

Geometric Modeling of Engineered Abrasive Processes  

Microsoft Academic Search

One of the common issues that arises in abrasive machining is the inconsistency of the surface roughness within the same batch and under identical machining conditions. Recent advances in engineered abrasives have allowed replacement of the random arrangement of minerals on conventional belts with precisely shaped structures uniformly cast directly onto a backing material. This allows for abrasive belts that

Andres L. Carrano; James B. Taylor

2005-01-01

235

Modeling organizations for information systems requirements engineering  

Microsoft Academic Search

In attempting to understand information system environments during requirements engineering, it is often helpful to have an understanding of the `whys' as well as the `whats' about the environment. A natural way to answer why questions is by tracing them to goals. In an organizational environment, however, the whys do not originate from a single set of given goals. Organizational

Eric S. K. Yu

1993-01-01

236

Modelling soot and SOF emissions from a diesel engine  

Microsoft Academic Search

Modelling of soot and SOF emissions from a typical European turbocharged diesel engine has been made. The model consists of a detailed kinetic mechanism with 472 reactions (120 chemical species) and data from the thermodynamic diagnostic procedure of the combustion process of the engine.The forward kinetic constants were obtained from literature and the background constants from a self-developed non-linear fitting

A. Durán; M. Carmona; J. M. Monteagudo

2004-01-01

237

Modeling and simulation of a hybrid-engine  

Microsoft Academic Search

A fundamental mathematical model is required to describe the dynamic motion of the hybrid-engine. Based on the mathematical model, simulation programs have been developed These programs are used to predict the operation of the motor\\/generator and to develop a control strategy. The simulation results are included. Two structures for the hybrid-engine have been considered. One uses a single cylinder and

Xiangqun Zhang; J. Katzberg; B. Cooke; J. Kos

1997-01-01

238

Nonlinear modeling and identification of a spark ignition engine torque  

NASA Astrophysics Data System (ADS)

The identification of mathematical models typically nonlinear systems is vital in many fields of engineering. This study presents nonlinear modeling and identification of spark ignition engine torque from input-output measurement. Nonlinear models for the system are obtained for identification purposes. The Hammerstein nonlinear system approach is used for identification of the nonlinear system model. Identification of nonlinear system models is performed using the recursive least squares method. The nonlinear system identification with fifth order linear dynamics gives the best result. And also selection of the second order nonlinearity gives the best result. The results are numerically and graphically presented.

Togun, Necla; Baysec, Sedat; Kara, Tolgay

2012-01-01

239

Numerical modeling of hydrogen-fueled internal combustion engines  

SciTech Connect

Major progress was achieved in the last year in advancing the modeling capabilities of hydrogen-fueled engines, both in support of the multi-laboratory project with SNL and LLNL to develop a high-efficiency, low emission powerplant and to provide the engine design tools to industry and research laboratories for hydrogen-fueled engines and stationary power generators. The culmination of efforts on many fronts was the excellent comparison of the experimental data from the Onan engine, operated by SNL.These efforts include the following. An extensive study of the intake flow culminated in a major understanding of the interdependence of the details of the intake port design and the engine operating condition on the emissions and efficiency. This study also resulted in design suggestions for future engines and general scaling laws for turbulence that enables the KIVA results to be applied to a wide variety of operating conditions. The research on the turbulent combustion of hydrogen brought into perspective the effect of the unique aspects of hydrogen combustion and their influence on possible models of turbulent combustion. The effort culminated in a proposed model for turbulent hydrogen combustion that is in agreement with available literature. Future work will continue the development in order to provide a generally predictive model for hydrogen combustion. The application of the combustion model to the Onan experiments elucidated the observed improvement of the efficiency of the engine with the addition of a shroud on the intake valve. This understanding will give guidance to future engine design for optimal efficiency. Finally, a brief summary is given of the extensions and refinements of the KIVA-3 code, in support of future designers of hydrogen-fueled engines.

Johnson, N.L.; Amsden, A.A.; Butler, T.D. [Los Alamos National Lab., NM (United States). Theoretical Div.

1996-07-01

240

Application of a closure model to predict crack growth in three engine disc materials  

Microsoft Academic Search

This paper describes the crack-growth predictions made in an AGARD Structures and Materials Panel, Engine Disc Cooperative\\u000a Programme [1, 2] using the life-prediction code FASTRAN II. The objective of the program was to compare various methods of\\u000a modeling crack-growth behavior in engine disc materials. The experimental database included three titanium alloys (Ti-6A1-4V,\\u000a IMI-685 and Ti-17) and two crack configurations (compact

J. C. Newman

1989-01-01

241

LEADER-an integrated engine behavior and design analyses based real-time fault diagnostic expert system for space shuttle main engine (SSME)  

Microsoft Academic Search

An expert system, called LEADER, has been designed and implemented for automatic learning, detection, identification, verification and correction of anomalous propulsion system operations in real time. LEADER employs a set of sensors to monitor engine component performance, and to detect, identify and validate abnormalities with respect to varying engine dynamics and behavior. Two diagnostic approaches are adopted in the architecture

U. K. Gupta; Moonis Ali

1989-01-01

242

Comparing leading theoretical models of behavioral predictions and post-behavior evaluations  

Microsoft Academic Search

This study aimed at comparing the predictive power of the Theory of Planned Behavior (TPB), the Model of Goal-Directed Behavior (MGB), and the Extended Model of Goal-Directed Behavior (EMGB) for observed and self-reported behaviors concerning consumer nondurables. More specifically, the three models were compared in terms of their predictive power for intention and for behavioral desire (only MGB and EMGB).

Juliette Richetin; Marco Perugini; Iqbal Adjali; Robert Hurling

2008-01-01

243

Beyond The Engineering Pedagogy: Engineering The Pedagogy, Modelling Kolb's Learning Cycle  

Microsoft Academic Search

Experiential Learning is a modern radical approach of conducting education. Kolb's four stages experiential learning model have been well received since it was proposed during mid 1980's. In this paper, we approach the analysis of Kolb's Cycle from an engineering point of view, where we develop a mathematical model of the learning curve when Kolb's experiential learning cycle is use.

Mahmoud Abdulwahed; Zoltan K Nagy; Richard Blanchard

2008-01-01

244

KBMS support for technical modeling in engineering systems  

Microsoft Academic Search

We suggest the use of technical modeling systems to introduce more semantics directly into the internal object representation. Firstly, we will introduce the technical modeling approach and the technical model as the basic concepts for an integrated engineering system. Then, we investigate the notion of “technical dependencies”, that can be characterized by the term technical constraints. They restrict the design

Bernd Sutter; S. DeBloch; C. Hubel; Nelson Mendonça Mattos

1990-01-01

245

Unifying Computer Forensics Modeling Approaches: A Software Engineering Perspective  

Microsoft Academic Search

As an effort to introduce formalism into computer forensics, researchers have presented various modeling techniques for planning, analysis, and documentation of forensics activities. These modeling techniques provide representations of various forensics subjects such as investigative processes, chain of events, and evidence tests. From a software engineering perspective, it seems that several of these computer forensics modeling approaches may be unified

A. Chris Bogen; David A. Dampier

2005-01-01

246

Engineers' Non-Scientific Models in Technology Education  

ERIC Educational Resources Information Center

|Engineers commonly use rules, theories and models that lack scientific justification. Examples include rules of thumb based on experience, but also models based on obsolete science or folk theories. Centrifugal forces, heat and cold as substances, and sucking vacuum all belong to the latter group. These models contradict scientific knowledge, but…

Norstrom, Per

2013-01-01

247

ROLES OF ONTOLOGIES OF ENGINEERING ARTIFACTS FOR DESIGN KNOWLEDGE MODELING  

Microsoft Academic Search

Capturing design knowledge and its modeling are crucial issues for design support systems and design knowledge management. It is important that knowledge models are systematic, consistent, reusable and interoperable. This survey article discusses the roles of ontologies of engineering artifacts for contributing to such design knowledge modeling from a viewpoint of computer science. An ontology of artifacts, in general, consists

YOSHINOBU KITAMURA

2006-01-01

248

Real-Time Rope Model Suitable for Game Engine Usage.  

National Technical Information Service (NTIS)

This thesis attempts to lay a foundation for producing a real-time rope model suitable for game engine usage. The model presented here is only one of the many possible approaches in modeling a rope. The basic premise used was derived from Erkin Tunca's so...

R. A. Garrido

2004-01-01

249

A Dynamic Usage Modelling Approach to Software Reliability Engineering  

Microsoft Academic Search

In software reliability engineering, reliability models have been in focus for years, while less attention has been given to usage models, which are necessary for usage based testing. The state hierarchy usage model is designed to capture the complex and dynamic usage behav- iour for large real-time software systems, for example telecommunica- tion systems. It provides a practical approach to

P. Runeson; C. Wohlin

1998-01-01

250

Optimization of Combustion Chamber for Diesel Engine Using Kriging Model  

Microsoft Academic Search

Diesel engine combustion chamber which reduces exhaust emission has been designed using CFD analysis and optimization techniques. In order to save computational time for design, the Kriging model, one of the response surface models, is adopted here. For a robust exploration, both the estimated function value of the model and its uncertainty are considered at the same time. In the

Shinkyu Jeong; Youichi Minemura; Shigeru Obayashi

2006-01-01

251

Modeling of nucleate boiling in engine cylinder head cooling ducts  

Microsoft Academic Search

The merits of various existing 1D models for nucleate subcooled boiling heat transfer are assessed. The implementation of these models is occasionally not straightforward. Some physical inconsistencies have been identified in these models. Surprisingly, the Chen correlation predicts the measurements best, in particular for data sets with heat fluxes in the range of a diesel engine.

J. P. Kroes; Velthooven van E

2008-01-01

252

Box-Cox Mixed Logit Model for Travel Behavior Analysis  

NASA Astrophysics Data System (ADS)

To represent the behavior of travelers when they are deciding how they are going to get to their destination, discrete choice models, based on the random utility theory, have become one of the most widely used tools. The field in which these models were developed was halfway between econometrics and transport engineering, although the latter now constitutes one of their principal areas of application. In the transport field, they have mainly been applied to mode choice, but also to the selection of destination, route, and other important decisions such as the vehicle ownership. In usual practice, the most frequently employed discrete choice models implement a fixed coefficient utility function that is linear in the parameters. The principal aim of this paper is to present the viability of specifying utility functions with random coefficients that are nonlinear in the parameters, in applications of discrete choice models to transport. Nonlinear specifications in the parameters were present in discrete choice theory at its outset, although they have seldom been used in practice until recently. The specification of random coefficients, however, began with the probit and the hedonic models in the 1970s, and, after a period of apparent little practical interest, has burgeoned into a field of intense activity in recent years with the new generation of mixed logit models. In this communication, we present a Box-Cox mixed logit model, original of the authors. It includes the estimation of the Box-Cox exponents in addition to the parameters of the random coefficients distribution. Probability of choose an alternative is an integral that will be calculated by simulation. The estimation of the model is carried out by maximizing the simulated log-likelihood of a sample of observed individual choices between alternatives. The differences between the predictions yielded by models that are inconsistent with real behavior have been studied with simulation experiments.

Orro, Alfonso; Novales, Margarita; Benitez, Francisco G.

2010-09-01

253

Modeling investment behavior under price cap regulation  

Microsoft Academic Search

Motivated by the frequently observed criticism of the regulatory practice arising from companies in the industries concerned,\\u000a we investigate the impact of regulation on investment behavior. Therefore, we model the investment timing and volume of a\\u000a firm acting in a regulated market. When capping prices, the regulatory authority imposes a price ceiling on market prices.\\u000a Accordingly, we use a real

Thomas Nagel; Margarethe Rammerstorfer

2009-01-01

254

Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior  

Microsoft Academic Search

Anomalous behavior of on-orbit spacecraft can often be detected using passive, remote sensors which measure electro-optical signatures that vary in time and spectral content. Analysts responsible for assessing spacecraft operational status and detecting detrimental anomalies using non-resolved imaging sensors are often presented with various sensing and identification issues. Modeling and measuring spacecraft self emission and reflected radiant intensity when the

B. Klem; D. Swann

2011-01-01

255

Machine Learning Approaches for Modeling Spammer Behavior  

Microsoft Academic Search

Spam is commonly known as unsolicited or unwanted email messages in the\\u000aInternet causing potential threat to Internet Security. Users spend a valuable\\u000aamount of time deleting spam emails. More importantly, ever increasing spam\\u000aemails occupy server storage space and consume network bandwidth. Keyword-based\\u000aspam email filtering strategies will eventually be less successful to model\\u000aspammer behavior as the spammer

Abdullah Al Mahmud

2010-01-01

256

The Senior High School Students' Learning Behavioral Model of STEM in PBL  

ERIC Educational Resources Information Center

|The purpose of the study was to explore a learning behavioral model of project-based learning (PBL) for senior high school students in the context of STEM (science, technology, engineering, and mathematics). Using "audio speakers" as the project theme, a series of tasks were designed to be solved using STEM knowledge via an online platform and…

Lou, Shi Jer; Liu, Yi Hui; Shih, Ru Chu; Tseng, Kuo Hung

2011-01-01

257

40 CFR 90.615 - Model year restrictions related to imported engines and equipment.  

Code of Federal Regulations, 2012 CFR

...Environment 21 2012-07-01 2012-07-01 false Model year restrictions related to imported engines and equipment...KILOWATTS Importation of Nonconforming Engines § 90.615 Model year restrictions related to imported engines and...

2012-07-01

258

Analysis of the Transtheoretical Model of Behavior Change  

Microsoft Academic Search

The focus of this paper is on the Transtheoretical Model of Behavior Change (TTM). A description of the model, the applications toward mod- ifying health behavior, and the model's criticisms will all be examined. Through research of published literature, the paper concludes that the model does in fact seem to support health behavior change and shows potential for effective, appropriate

James A. Lenio

259

Modeling Crowd Behavior Based on Social Comparison Theory: Extended Abstract  

Microsoft Academic Search

Modeling crowd behavior is an important challenge for cog- nitive modelers. We propose a novel model of crowd behavior, based on Festinger's Social Comparison Theory, a social psychology theory known and expanded since the early 1950's. We propose a concrete framework for SCT, and evaluate its implementations in several crowd behavior scenarios. The results show improved performance over existing models.

Natalie Fridman; Gal A. Kaminka

2006-01-01

260

Relevance of Behavioral and Social Models to the Study of Consumer Energy Decision Making and Behavior.  

National Technical Information Service (NTIS)

This report reviews social and behavioral science models and techniques for their possible use in understanding and predicting consumer energy decision making and behaviors. A number of models and techniques have been developed that address different aspe...

B. A. Burns

1980-01-01

261

Model based feed-forward control of electromagnetic type active control engine-mount system  

NASA Astrophysics Data System (ADS)

This paper introduces a low-cost prototype active control engine mount (ACM) designed for commercial passenger vehicles, requiring a good engine vibration isolation performance. To construct such an ACM system, all feedback sensors normally required for full ACM systems are replaced by the model based feed forward algorithm, consisting of a vibration estimation algorithm, a current shaping controller and an enhanced ACM model. The ACM model describes the active as well as passive characteristics of ACM. The current shaping control compensates for degradation of control performance due to elimination of feedback control sensors. The engine vibration estimator, which uses such existing sensors as CAM and crank angle sensor (CAS), replaces a sensor to monitor the transmitted vibrations from the engine to the chassis. The validity of the ACM model is experimentally verified so that it accurately predicts the dynamic behaviors of the ACM over the frequency range of interest. The proposed current shaping control improves the actuator control performance, and the vibration estimation algorithm provides the anti-vibration signals for vibration isolation. Finally, it is experimentally proved that the vibration isolation performance of the developed ACM for the engine-induced vibration of interest can be improved by more than 13 dB.

Lee, Bo-Ha; Lee, Chong-Won

2009-06-01

262

Aerodynamic Characteristics of a Large-Scale Lift-Engine Fighter Model with External Swiveling Lift-Engines.  

National Technical Information Service (NTIS)

The aerodynamic characteristics of a six-engine (four lift, two lift-cruise) lift-engine model obtained in the Ames 40- by 80-foot wind tunnel are presented. The model was an approximate one-half scale representation of a lift-engine VTOL fighter aircraft...

J. P. Barrack J. V. Kirk

1972-01-01

263

Systems metabolic engineering: Genome-scale models and beyond  

PubMed Central

The advent of high throughput genome-scale bioinformatics has led to an exponential increase in available cellular system data. Systems metabolic engineering attempts to use data-driven approaches – based on the data collected with high throughput technologies – to identify gene targets and optimize phenotypical properties on a systems level. Current systems metabolic engineering tools are limited for predicting and defining complex phenotypes such as chemical tolerances and other global, multigenic traits. The most pragmatic systems-based tool for metabolic engineering to arise is the in silico genome-scale metabolic reconstruction. This tool has seen wide adoption for modeling cell growth and predicting beneficial gene knockouts, and we examine here how this approach can be expanded for novel organisms. This review will highlight advances of the systems metabolic engineering approach with a focus on de novo development and use of genome-scale metabolic reconstructions for metabolic engineering applications. We will then discuss the challenges and prospects for this emerging field to enable model-based metabolic engineering. Specifically, we argue that current state-of-the-art systems metabolic engineering techniques represent a viable first step for improving product yield that still must be followed by combinatorial techniques or random strain mutagenesis to achieve optimal cellular systems.

Blazeck, John; Alper, Hal

2010-01-01

264

Impact of modeling on adolescent suicidal behavior.  

PubMed

The evidence to date suggests that suicide modeling is a real phenomenon, although of a smaller effect size than other psychiatric and psychosocial risk factors for adolescent suicide. Multiple lines of inquiry provide converging evidence, including studies on suicide clusters, media influence on suicide (particularly coverage of nonfictional suicides), and peer influence on suicidality. Despite variations in study setting and methodology, the body of literature is consistent with a modeling hypothesis. Although advances in documentation of suicide modeling have been made over the past decade, we are still confronted by unresolved issues regarding the underlying mechanisms. Prevention and postvention strategies can be optimized to avert modeling of suicidal behavior only once research addresses the complexities and uncertainties of this phenomenon. PMID:18439450

Insel, Beverly J; Gould, Madelyn S

2008-06-01

265

Theoretical models of Gamma-Ray Burst central engines  

Microsoft Academic Search

The rapid variability and large energies that characterize Gamma-Ray Bursts (GRBs) strongly implicate neutron stars or stellar-mass black holes as their central engines. In this thesis, I develop theoretical models of both accretion powered and spin-down-powered central engines and apply them to long- and short-duration GRBs. This research covers several topics, including: (1) The effects of strong magnetic fields and

Brian David Metzger

2009-01-01

266

Building a Narrative Based Requirements Engineering Mediation Model  

Microsoft Academic Search

Abstract. This paper presents a narrative-based Requirements,Engineering (RE) mediation model to help RE practitioners to effectively identify, define, and resolve conflicts of interest, goals, and requirements. With SPI community, there is a common belief that social, human, and organizational issues significantly impact on the effectiveness of the software process improvement in general and,requirements,engineering,process in particularly. Conflicts among,different stakeholders are an

Nan Ma; Tracy Hall; Trevor Barker

2008-01-01

267

Case Studies in Process Modeling (Engineering Statistics Handbook)  

NSDL National Science Digital Library

The online Engineering Statistics Handbook provides a section (4.6 Case Studies in Process Modeling) using detailed realistic examples from physical science and engineering applications. Examples in load cell calibration, Alaska Pipeline ultrasonic calibration, ultrasonic reference block study, and thermal expansion of copper case study are presented in a step-by-step manner. This is a great collection of studies showing real world uses of statistics.

Filliben, James; Heckert, Alan

2009-02-03

268

Behavior of reoccurring PARAFAC components in fluorescent dissolved organic matter in natural and engineered systems: a critical review.  

PubMed

Fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) has been widely used to characterize dissolved organic matter (DOM). Characterization is based on the intensity and location of independent fluorescent components identified in models constructed from excitation-emission matrices (EEMs). Similar fluorescent components have been identified in PARAFAC studies across a wide range of systems; however, there is a lack of discussion regarding the consistency with which these similar components behave. The overall goal of this critical review is to compare results for PARAFAC studies published since the year 2000 which include one or more of three reoccurring humic-like components. Components are compared and characterized based on EEM location, characteristic ecosystems, and behavior in natural and engineered systems. This synthesis allows PARAFAC users to more confidently infer DOM characteristics based on identified components. Additionally, behavioral inconsistencies between similar components help elucidate DOM properties for which fluorescence spectroscopy with PARAFAC may be a weak predictive tool. PMID:22280543

Ishii, Stephanie K L; Boyer, Treavor H

2012-02-07

269

ADSM -- An automated distribution system modeling tool for engineering analyses  

SciTech Connect

Designing and operating the distribution system efficiently and economically requires distribution engineers to perform various analytical studies frequently. The system models for these analyses are derived from the information residing in diverse utility databases. One major problem in utilizing these databases is the data mismatch due to different software specifications and hardware platforms. This means additional effort is required to transform data among these systems before engineers can perform any distribution system analyses. The Automated Distribution System Modeler (ADSM) developed jointly at the University of Washington (UW) and Puget Sound Power and Light Co. (PSPL) provides an automated approach for the distribution system modeling. This software tool builds a unified distribution system model automatically from the utility databases and provides a generic interface to various engineering analysis tools. This paper describes the Object-Oriented design concept of such a tool and discusses the merits of the Geographic Information System (GIS) environment used as a platform for ADSM.

Wei, X.G.; Venkata, S.S. [Univ. of Washington, Seattle, WA (United States). Electric Energy Group; Sumic, Z. [Univ. of Washington, Seattle, WA (United States). Electric Energy Group]|[Puget Sound Power and Light Co., Bellevue, WA (United States)

1995-02-01

270

NTP system simulation and detailed nuclear engine modeling  

NASA Astrophysics Data System (ADS)

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

Anghaie, Samim

271

Analysis of mean value engine model with emphasis on intake manifold thermal effects  

Microsoft Academic Search

A mean value engine model with a polytropic intake manifold sub-model is presented and experimentally validated. A detailed comparative algebraic analysis of the engine model for the special cases of isothermal and adiabatic manifold heat transfers is carried out based on the linearized form of the engine model. The analysis is illustrated by simulation results for different engine operating modes.

JoSko Deur; Davor Hrovat; Jahan Asgari

2003-01-01

272

Engineering behavior of the Lisan Marl as a dyke foundation material: Dead Sea, Jordan  

Microsoft Academic Search

Problems have occurred with dykes constructed on the Lisan Marl to retain brine pumped from the Dead Sea, which is chemically\\u000a processed to produce potash. In this study the engineering behavior, collapse potential and compressibility of the Lisan Marl\\u000a were assessed by undertaking laboratory tests with both natural, distilled water and brine as the media. The results showed\\u000a that the

Ziad Mansour; Mohd Raihan Taha; Zamri Chik

2009-01-01

273

Visualization of liquid fuel behavior in a spark ignition engine during starting and warm-up  

Microsoft Academic Search

The liquid fuel behavior in the intake port and the cylinder during starting and warm-up was visualized through visualization\\u000a windows using a high speed CCD camera. The videos were taken with the engine firing under cold conditions in the simulated\\u000a start up process, at 1.000 and 1.200 RPM and intake manifold pressure of 0.5 bar. The variables examined were the

Younggy Shin

1997-01-01

274

Environmental behavior and ecotoxicity of engineered nanoparticles to algae, plants, and fungi  

Microsoft Academic Search

Developments in nanotechnology are leading to a rapid proliferation of new materials that are likely to become a source of\\u000a engineered nanoparticles (ENPs) to the environment, where their possible ecotoxicological impacts remain unknown. The surface\\u000a properties of ENPs are of essential importance for their aggregation behavior, and thus for their mobility in aquatic and\\u000a terrestrial systems and for their interactions

Enrique Navarro; Anders Baun; Renata Behra; Nanna B. Hartmann; Juliane Filser; Ai-Jun Miao; Antonietta Quigg; Peter H. Santschi; Laura Sigg

2008-01-01

275

An engineering model for short-channel MOS devices  

Microsoft Academic Search

An engineering model for short-channel MOS devices which includes the effect of carrier drift velocity saturation is described. Based on a piecewise carrier drift velocity model, simplified expressions for the dc drain current I,, the small-signal transconductance g,,,, and the output conductance g,, in the saturation region are derived. For a given gate voltage, the expressions depend only on the

KAI-YAP TOH; PING-KEUNG KO; ROBERT G. MEYER

1988-01-01

276

A Team Building Model for Software Engineering Courses Term Projects  

ERIC Educational Resources Information Center

|This paper proposes a new model for team building, which enables teachers to build coherent teams rapidly and fairly for the term projects of software engineering courses. Moreover, the model can also be used to build teams for any type of project, if the team member candidates are students, or if they are inexperienced on a certain subject. The…

Sahin, Yasar Guneri

2011-01-01

277

Towards Variability Modelling for Reuse in Hypermedia Engineering  

Microsoft Academic Search

In this paper we discuss variability modelling for hypermedia applications. Inspired by domain engineering, we propose a domain engi- neering based method for hypermedia development. Since several adap- tive hypermedia become more and more popular to incorporate dierent information views for dierent audience or environments, we believe that it is important to move variability capturing to modelling phases. Several established

Peter Dolog; Mária Bieliková

2002-01-01

278

Engineering-Economic Model of Residential Energy Use.  

National Technical Information Service (NTIS)

This report describes a comprehensive engineering-economic computer model used to simulate energy use in the residential sector from 1970 to 2000. The purpose of the model is to provide an analytical tool with which to evaluate a variety of conservation p...

E. Hirst W. Lin J. Cope

1976-01-01

279

A structural model of engineering students success and persistence  

Microsoft Academic Search

This study examined a model of student success and persistence at two levels: university and engineering major. The model, based on theoretical and empirical evidence, included both cognitive and noncognitive factors. Cognitive factors included high school rank, scholastic aptitude scores, and university grade point average. Noncognitive factors included motivation, as well as faculty and student integration. Outcome variables in the

Brian F. French; Jason C. Inzntekus; William Oakes

2003-01-01

280

Model Specification for Composites for Civil Engineering Structures  

Microsoft Academic Search

A proposed model specification for FRP composite materials for use in civil engineering structural systems is described in this article. The model specification provides a classification systems for FRP materials, describes admissible constituent materials and limits on selected constituent volumes, describes tests for specified mechanical and physical properties, specifies limiting values of selected properties in the as-received condition and in

Lawrence C. Bank; T. Russell Gentry; Benjamin P. Thompson; Jeffrey S. Russell

2002-01-01

281

Model-based engine fault detection and isolation  

Microsoft Academic Search

To a large extent, tailpipe emissions are influenced by the accuracy and reliability of the intake manifold sensors and the predictive models used for cylinder charge estimation. In this paper, mathematical models of an internal combustion engine are employed to detect failures in the intake manifold. These can be associated with the upstream sensors such as the pressure and temperature

Arkadiusz Dutka; Hossein Javaherian; Michael J. Grimble

2009-01-01

282

Modeling score distributions for combining the outputs of search engines  

Microsoft Academic Search

In this paper the score distributions of a number of text search engines are modeled. It is shown empirically that the score distributions on a per query basis may be fitted using an exponential distribution for the set of non-relevant documents and a normal distribution for the set of relevant documents. Experiments show that this model fits TREC-3 and TREC-4

R. Manmatha; Toni M. Rath; Fangfang Feng

2001-01-01

283

Three and more dimensional modelling in geo-engineering  

Microsoft Academic Search

Full three-dimensional modelling has been developed and is implemented for many sites where engineering structures are built. Such computer models of the subsurface allow for a more sophisticated handling of subsurface data leading to, for example, better dimensioning of geotechnical units, the evaluation of hazard and risk, foundation design, tunnel routing, planning and building, etc. Other applications are the back-analysis

Robert Hack; Bogdan Orlic; Senol Ozmutlu; Sicai Zhu; Niek Rengers

2006-01-01

284

Two-Compartment Pharmacokinetic Models for Chemical Engineers  

ERIC Educational Resources Information Center

|The transport of potassium permanganate between two continuous-stirred vessels was investigated to help chemical and biomedical engineering students understand two-compartment pharmacokinetic models. Concepts of modeling, mass balance, parameter estimation and Laplace transform were applied to the two-unit process. A good agreement was achieved…

Kanneganti, Kumud; Simon, Laurent

2011-01-01

285

Social Network Models for Enhancing Reference Based Search Engine Rankings  

Microsoft Academic Search

This chapter elaborates on a twofold approach on models of web search engine retrieval and more specifically the way information resources are ranked in the query results. In particular, current models of information retrieval are blind to the social context that surrounds information resources thus do not consider the trustworthiness of their authors when they present the query results to

Nikolaos Korfiatis; Miguel-Angel Sicilia; Claudia Hess; Klaus Stein; Christoph Schlieder

286

Teaching Geometry through Dynamic Modeling in Introductory Engineering Graphics.  

ERIC Educational Resources Information Center

|Examines how constraint-based 3D modeling can be used as a vehicle for rethinking instructional approaches to engineering design graphics. Focuses on moving from a mode of instruction based on the crafting by students and assessment by instructors of static 2D drawings and 3D models. Suggests that the new approach is better aligned with…

Wiebe, Eric N.; Branoff, Ted J.; Hartman, Nathan W.

2003-01-01

287

Modular Concurrent Engineering Models: Enabling Alternative Models in Conceptual Satellite Design  

Microsoft Academic Search

Design groups have worked for many years to provide rapid development and modeling of conceptual space vehicles using Concurrent Engineering Models (CEMs). A large number of design tools have been crafted to meet different aims and goals within the systems engineering community.The challenges to build upon these previous models to generate a flexible CEM capable of using interchangeable modules that

Brian Lewis; Jeff Lang; Richa Jolly

2007-01-01

288

Hydraulic features of Engineered Log Jams (ELJs) and their influence on salmonid behavior  

NASA Astrophysics Data System (ADS)

In an effort to recreate channel complexity and habitat, construction of Engineered Log Jams (ELJs) is increasing, yet questions remain regarding their effectiveness due to lack of observations of hydraulics and fish use around these structures. To address this limitation, we surveyed four different forms of engineered log jams in western Oregon. The structures and near-structure stream environments were surveyed for bathymetry, instrumented with an Acoustic Doppler Stream Profiler (ADCP) to measure velocities, and snorkeled to observe the behavior of salmonids. Further, tensor visualization of stream velocities were constructed to investigate circulation and flow patterns in and around the ELJ structures. We found that more complex structures created a more varied bottom profile, while simpler structures resulted in more simple pools. However, all log jams did increase the diversity of flow patterns, with areas of high and low velocity that appeared to influence fish behavior. Variation in the size of salmonids was related to greater variation in the velocity, and fish behavior (feeding, aggression) was observed to vary within the pools. Our results provide preliminary evidence of the influence of engineered structures on the diversity and versatility of fish habitat.

Rice, W. D.; Fetter, D.; Somerville, G.; Tullos, D. D.; Palacijo, J.

2010-12-01

289

Mathematical modeling of the behavior of geothermal systems under exploitation  

SciTech Connect

Analytical and numerical methods have been used in this investigation to model the behavior of geothermal systems under exploitation. The work is divided into three parts: (1) development of a numerical code, (2) theoretical studies of geothermal systems, and (3) field applications. A new single-phase three-dimensional simulator, capable of solving heat and mass flow problems in a saturated, heterogeneous porous or fractured medium has been developed. The simulator uses the integrated finite difference method for formulating the governing equations and an efficient sparse solver for the solution of the linearized equations. In the theoretical studies, various reservoir engineering problems have been examined. These include (a) well-test analysis, (b) exploitation strategies, (c) injection into fractured rocks, and (d) fault-charged geothermal reservoirs.

Bodvarsson, G.S.

1982-01-01

290

THE INTERNAL ORGANIZATION OF COMPUTER MODELS OF COGNITIVE BEHAVIOR.  

ERIC Educational Resources Information Center

|IF COMPUTER PROGRAMS ARE TO SERVE AS USEFUL MODELS OF COGNITIVE BEHAVIOR, THEIR CREATORS MUST FACE THE NEED TO ESTABLISH AN INTERNAL ORGANIZATION FOR THEIR MODEL WHICH IMPLEMENTS THE HIGHER LEVEL COGNITIVE BEHAVIORS ASSOCIATED WITH THE HUMAN CAPACITY FOR SELF-DIRECTION, AUTOCRITICISM, AND ADAPTATION. PRESENT COMPUTER MODELS OF COGNITIVE BEHAVIOR

BAKER, FRANK B.

291

Engineered antifouling microtopographies: an energetic model that predicts cell attachment.  

PubMed

We have developed a model for the prediction of cell attachment to engineered microtopographies based on two previous models: the attachment point theory and the engineered roughness index (ERI) model. The new surface energetic attachment (SEA) model is based on both the properties of the cell-material interface and the size and configuration of the topography relative to the organism. We have used Monte Carlo simulation to examine the SEA model's ability to predict relative attachment of the green alga Ulva linza to different locations within a unit cell. We have also compared the predicted relative attachment for Ulva linza, the diatom Navicula incerta, the marine bacterium Cobetia marina, and the barnacle cyprid Balanus amphitrite to a wide variety of microtopographies. We demonstrate good correlation between the experimental results and the model results for all tested experimental data and thus show the SEA model may be used as a powerful indicator of the efficacy for antifouling topographies. PMID:24044383

Decker, Joseph T; Kirschner, Chelsea M; Long, Christopher J; Finlay, John A; Callow, Maureen E; Callow, James A; Brennan, Anthony B

2013-10-08

292

Design with part behaviors: behavior model, representation and applications  

Microsoft Academic Search

A part is primarily characterized by its ‘function(s)’. The function of the part is achieved through its ‘interactions’ with other parts in an assembly under a set of operating conditions. These ‘interactions’ constitute the ‘behavior’ of the part. The ‘part behavior’ is achieved through a set of spatial and design functional relationships between the interacting surfaces of the parts. The

Utpal Roy; Balaji Bharadwaj

2002-01-01

293

A behavior-based model for pedestrian counter flow  

Microsoft Academic Search

A behavior-based lattice-gas model for pedestrian dynamics is presented. This model adopts the behaviorism for mobile robot, and the walk task of pedestrian can be divided into three basic behaviors, i.e., “move”, “avoid”, and “swirl” basic behaviors. The walk direction is determined from the walk weight, which is the sum of the product of each vector of basic behavior multiplied

W. G. Weng; S. F. Shen; H. Y. Yuan; W. C. Fan

2007-01-01

294

A behavior-based model for pedestrian counter flow  

Microsoft Academic Search

A behavior-based lattice-gas model for pedestrian dynamics is presented. This model adopts the behaviorism for mobile robot, and the walk task of pedestrian can be divided into three basic behaviors, i.e., ``move'', ``avoid'', and ``swirl'' basic behaviors. The walk direction is determined from the walk weight, which is the sum of the product of each vector of basic behavior multiplied

W. G. Weng; S. F. Shen; H. Y. Yuan; W. C. Fan

2007-01-01

295

Small fatigue crack growth in metallic materials: A model and its application to engineering alloys  

SciTech Connect

Characterization of the growth behavior of small fatigue cracks is important for materials used in structurally demanding applications such as aircraft turbine discs and some automotive engine components. Here, we present a general, dislocation-based fracture mechanics approach to predict the growth rate of small fatigue cracks in metallic materials. The applicability of the model to the small fatigue crack growth behavior of four engineering alloys was examined. Small fatigue cracks were initiated and propagated, in a controlled manner, from micronotches fabricated by femtosecond pulsed laser micromachining. The results suggest that a methodology consisting of crack-tip damage accumulation and fracture provides a common framework to estimate the fatigue crack propagation lifetime of structural materials.

Shyam, Amit [ORNL

2007-01-01

296

MODELING OPERANT BEHAVIOR IN THE PARKINSONIAN RAT  

PubMed Central

Mathematical principles of reinforcement (MPR; Killeen, 1994) is a quantitative model of operant behavior that contains 3 parameters representing motor capacity (?), motivation (a), and short term memory (?). The present study applied MPR to characterize the effects of bilateral infusions of 6-OHDA into the substantia nigra pars compacta in the rat, a model of Parkinson’s disease. Rats were trained to lever press under a 5-component fixed ratio (5, 15, 30, 60, and 100) schedule of food reinforcement. Rats were tested for 15 days prior to dopamine lesions and again for 15 days post-lesion. To characterize functional loss relative to lesion size, rats were grouped according to the extent and the degree of lateralization of their dopamine loss. Response rates decreased as a function of dopamine depletion, primarily at intermediate ratios. MPR accounted for 98% of variance in pre- and post-lesion response rates. Consistent with reported disruptions in motor behavior induced by dopaminergic lesions, estimates of ? increased when dopamine was severely depleted. There was no support for different estimates of a based on pre- and post-lesion performance of any lesion group, suggesting that dopamine loss has negligible effects on incentive motivation. The present study demonstrates the usefulness of combining operant techniques with a theoretical model to better understand the effects of a neurochemical manipulation.

Avila, Irene; Reilly, Mark P.; Sanabria, Federico; Posadas-Sanchez, Diana; Chavez, Claudia L.; Banerjee, Nikhil; Killeen, Peter; Castaneda, Edward

2009-01-01

297

Molecular Modeling of Solid Fluid Phase Behavior  

SciTech Connect

This report gives a summary of the achievements under DOE contract No. DOE/ER/14150 during the period September 1, 1990 to December 31, 2007. This project was concerned with the molecular modeling of solid-fluid equilibrium. The focus was on understanding how solid-fluid and solid-solid phase behavior are related to molecular structure, and the research program made a seminal contribution in this area. The project led to 34 journal articles, including a comprehensive review article published in Advances in Chemical Physics. The DOE funding supported the work of 5 Ph.D. students, 2 M.S. students and 5 postdoctoral researchers.

Peter A. Monson

2007-12-20

298

Model-Driven Visual Requirements Engineering  

Microsoft Academic Search

This paper describes the requirements handling process of a set of research projects, the ATHENA IP, and how this process is supported by modeling and visualizing requirement structures. First, users and external stakeholders register requirements through easy-to-use web interfaces. Then developers and man- agers utilize an integrated modeling tool for visual classification, analysis, elicitation, and selection of requirements. In this

Helge Grenager Solheim; Frank M. Lillehagen; Sobah Abbas Petersen; Håvard D. Jørgensen; Maria Anastasiou

2005-01-01

299

Adaptive Ground Modelling in geotechnical engineering  

Microsoft Academic Search

Geotechnical design depends on parameters got from field investigations. Therefore the devel- opment of subsoil models for assessing the behaviour of the subsoil has a strong influence on the reliability of geotechnical structures. The contribution deals with an adaptive improvement of soil models using geostatis- tical methods, demonstrated for a data set of a simplified practical example. Starting with subjective

M. Schönhardt; K. J. Witt

300

Model thermal engine cycles for photovoltaic cells  

Microsoft Academic Search

Model cycles were developed that represent the operation of photovoltaic cells. The models are based on the assumption that the photoexcited minority carriers can be considered to be in thermal equilibrium state at a metastable equilibrium state considerably in excess of the lattice temperature. This assumption is justified on the basis of comparisons between equilibration times that describe the rates

Beladi

1982-01-01

301

Generic engine for user model based adaptation  

Microsoft Academic Search

User model based adaptation becomes more and more important in interactive systems. In this paper we first review the different possible adaptation models and discuss the concepts of push, pull and hybrid adaptation. At this moment there are few published applications that explicitly use hybrid adaptation. We thus propose a way to add hybrid adaptation (which also provides push and

P. T. de Vrieze; P. van Bommel; Th. P. van der Weide

2004-01-01

302

Animal models for vascular tissue-engineering.  

PubMed

Because of rise in cardiovascular disease throughout the world, there is increasing demand for small diameter blood vessels as replacement grafts. The present review focuses on the animal models that have been used to test small-diameter TEVs with emphasis on the attributes of each model. Small animal models are used to test short-term patency and address mechanistic hypotheses; and large, preclinical animal models are employed to test long-term patency, remodeling and function in an environment mimicking human physiology. We also discuss recent clinical trials that employed laboratory fabricated TEVs and showed very promising results. Ultimately, animal models provide a testing platform for optimizing vascular grafts before clinical use in patients without suitable autologous vessels. PMID:23769861

Swartz, Daniel D; Andreadis, Stelios T

2013-06-13

303

Behavioral model and simulator for the Multi-slit Optimized Spectrometer (MOS)  

NASA Astrophysics Data System (ADS)

The Multi-Slit Optimized Spectrometer (MOS) is a NASA funded Instrument Incubator Program (IIP) to advance an innovative dispersive spectrometer concept in support of the GEO-CAPE ocean science mission. As part of the instruments design and testing, we constructed a `behavioral model' of the instrument's optical engine which allows an end-to-end simulation from input radiances to nal product maps. Here we describe the model used for a rapid, but realistic, simulation of the MOS optical engine, and give illustrative examples of quantitatively tracking errors in the imaging chain from input radiances to bounds on nal product errors.

Tufillaro, Nicholas; Davis, Curtiss O.; Valle, Tim; Good, William; Stephens, Michelle; Spuhler, Peter

2013-09-01

304

Modeling and laser-based sensing of pulsed detonation engines  

Microsoft Academic Search

This work is concerned with two major aspects of pulse detonation engines (PDE) research: modeling and laser-based sensing. The modeling addresses both ideal and real considerations relevant to PDE design. First, an ideal nozzle model is developed which provides a tool for choosing area ratios for fixed-geometry converging, diverging, or converging-diverging nozzles. Next, losses associated with finite-rate chemistry are investigated.

Ethan A. Barbour

2009-01-01

305

SEISMIC MODELING ENGINES PHASE 1 FINAL REPORT  

Microsoft Academic Search

Seismic modeling is a core component of petroleum exploration and production today. Potential applications include modeling the influence of dip on anisotropic migration; source\\/receiver placement in deviated-well three-dimensional surveys for vertical seismic profiling (VSP); and the generation of realistic data sets for testing contractor-supplied migration algorithms or for interpreting AVO (amplitude variation with offset) responses.;\\u000aThis project was designed to

BRUCE P. MARION

2006-01-01

306

Genetically engineered mouse models of Parkinson's disease  

PubMed Central

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder, affecting more than 1% of the population over age 60. The most common feature of PD is a resting tremor, though there are many systemic neurological effects, such as incontinence and sleep disorders. PD is histopathologically identified by the presence of Lewy bodies (LB), proteinaceous inclusions constituted primarily by ?-synuclein. To date, there is no effective treatment to slow or stop disease progression. To help understand disease pathogenesis and identify potential therapeutic targets, many genetic mouse models have been developed. By far the most common of these models are the wildtype and mutant ?-synuclein transgenic mice, because ?-synuclein was the first protein shown to have a direct effect on PD pathogenesis and progression. There are many other gene-disrupted or -mutated models currently available, which are based on genetic anomalies identified in the human disease. In addition, there are also models which examine genes that may contribute to disease onset or progression but currently have no identified causative PD mutations. These genes are part of signaling pathways important for maintaining neuronal function in the nigrostriatal pathway. This review will summarize the most commonly used of the genetic mouse models currently available for PD research. We will examine how these models have expanded our understanding of PD pathogenesis and progression, as well as aided in identification of potential therapeutic targets in this disorder.

Crabtree, Donna M; Zhang, Jianhua

2011-01-01

307

Communicating to Farmers about Skin Cancer: The Behavior Adaptation Model.  

ERIC Educational Resources Information Center

|States health campaign messages designed to encourage behavior adaptation have greater likelihood of success than campaigns promoting avoidance of at-risk behaviors that cannot be avoided. Tests a model of health risk behavior using four different behaviors in a communication campaign aimed at reducing farmers' risk for skin cancer--questions…

Parrott, Roxanne; Monahan, Jennifer; Ainsworth, Stuart; Steiner, Carol

1998-01-01

308

Aging behavior and lifetime modeling for polycarbonate  

SciTech Connect

In this paper, polycarbonate (PC) as a material candidate for solar absorber applications is investigated as to the aging behavior at different temperatures in air and water. The aging conditioning was performed in air in the temperature range from 120 to 140 C and in water between 70 and 95 C. Tensile tests were performed on unaged and aged PC film specimens at ambient temperature using strain-to-break values as a performance indicator for the degree of aging. For PC the effect of aging was found to strongly depend on the aging conditions. Activation energy based lifetime prediction models according to various methods described in the literature were applied. The activation energies and corresponding lifetime predictions for the temperature range from 40 to 60 C in water and from 90 to 110 C in air derived from these models are compared and interpreted as to their practical relevance. (author)

Kahlen, S. [Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, Leoben 8700 (Austria); Wallner, G.M. [Institute of Materials Science and Testing of Plastics, University of Leoben, Franz-Josef Strasse 18, Leoben 8700 (Austria); Lang, R.W. [Institute for Polymeric Materials and Testing, University of Linz, Altenbergerstrasse 69, Linz 4040 (Austria)

2010-05-15

309

Modeling Impact Behavior of Glass with Peridynamics  

NASA Astrophysics Data System (ADS)

Glass is being considered for various transparent armor applications due to its high compressive strength. However, its low tensile properties lead to cracks and fractures if significant tensile stresses are present. Presence of surface cracks in combination with high tensile stresses lead to dynamic failure, sometimes in an explosive manner. We have conducted bar impact experiments as well as ballistic tests to study their penetration behavior. Numerical simulation of these experiments is a challenge. The existing hydrocodes do not provide satisfactory results for brittle materials. This can be attributed to significant differences in constitutive behavior between brittle and ductile materials and the need to account for many fracture surfaces. A new numerical method, peridynamics---a meshless Lagrangian method solving the equation of motion in integral form---has been proposed by Stewart Silling that appears to be more suitable for modeling brittle materials. We use this method to examine the response of glass to impact loads in both bar impact and penetration experiments. This paper will discuss advantages and difficulties in modeling glass with peridynamics.

Satapathy, S.; Dawson, A.; Bless, S.; Polyzois, I.; Rodin, G.

2009-06-01

310

Model-based diagnosis of large diesel engines based on angular speed variations of the crankshaft  

NASA Astrophysics Data System (ADS)

This work aims at monitoring large diesel engines by analyzing the crankshaft angular speed variations. It focuses on a powerful 20-cylinder diesel engine with crankshaft natural frequencies within the operating speed range. First, the angular speed variations are modeled at the crankshaft free end. This includes modeling both the crankshaft dynamical behavior and the excitation torques. As the engine is very large, the first crankshaft torsional modes are in the low frequency range. A model with the assumption of a flexible crankshaft is required. The excitation torques depend on the in-cylinder pressure curve. The latter is modeled with a phenomenological model. Mechanical and combustion parameters of the model are optimized with the help of actual data. Then, an automated diagnosis based on an artificially intelligent system is proposed. Neural networks are used for pattern recognition of the angular speed waveforms in normal and faulty conditions. Reference patterns required in the training phase are computed with the model, calibrated using a small number of actual measurements. Promising results are obtained. An experimental fuel leakage fault is successfully diagnosed, including detection and localization of the faulty cylinder, as well as the approximation of the fault severity.

Desbazeille, M.; Randall, R. B.; Guillet, F.; El Badaoui, M.; Hoisnard, C.

2010-07-01

311

Overview of Heat Transfer and Fluid Flow Problem Areas Encountered in Stirling Engine Modeling.  

National Technical Information Service (NTIS)

NASA Lewis Research Center has been managing Stirling engine development programs for over a decade. In addition to contractual programs, this work has included in-house engine testing and development of engine computer models. Attempts to validate Stirli...

R. C. Tew

1988-01-01

312

EHF (Extremely High Frequency) telecommunications system engineering model  

NASA Astrophysics Data System (ADS)

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

Allen, K. C.

1986-04-01

313

Guidelines for modeling power electronics in electric power engineering applications  

SciTech Connect

This paper presents a summary of guidelines for modeling power electronics in various power engineering applications. This document is designed for use by power engineers who need to simulate power electronic devices and sub-systems with digital computer programs. The guideline emphasizes the basic issues that are critical for successfully modeling power electronics devices and the interface between power electronics and the utility or industrial system. The modeling considerations addressed in this guideline are generic for all power electronics modeling independent of the computational tool. However, for the purposes of illustration, the simulation examples presented are based on the EMTP or EMTP type of programs. The procedures used to implement power electronics models in these examples are valuable for using other digital simulation tools.

NONE

1997-01-01

314

A Simplified Analysis on a Pulse Detonation Engine Model  

NASA Astrophysics Data System (ADS)

The performance of pulse detonation engines was analytically estimated by using a simple model. A pulse detonation engine was modeled as a straight tube. One end of the tube was closed and the other was open, and a detonation wave was ignited at the closed end. One cycle of the pulse-detonation-engine operation was divided into three phases: combustion, exhaust, and filling phases. The combustion and exhaust phases were theoretically analyzed with some simplifications, using the Hugoniot relation for the Chapman-Jouguet detonation wave and flow relations for self-similar rarefaction waves. Based on the simplified theoretical analysis, useful formulas for impulse density per one-cycle operation and time-averaged thrust density were derived.

Endo, Takuma; Fujiwara, Toshi

315

Building a Narrative Based Requirements Engineering Mediation Model  

NASA Astrophysics Data System (ADS)

This paper presents a narrative-based Requirements Engineering (RE) mediation model to help RE practitioners to effectively identify, define, and resolve conflicts of interest, goals, and requirements. Within the SPI community, there is a common belief that social, human, and organizational issues significantly impact on the effectiveness of software process improvement in general and the requirements engineering process in particularl. Conflicts among different stakeholders are an important human and social issue that need more research attention in the SPI and RE community. By drawing on the conflict resolution literature and IS literature, we argue that conflict resolution in RE is a mediated process, in which a requirements engineer can act as a mediator among different stakeholders. To address socio-psychological aspects of conflict in RE and SPI, Winslade and Monk (2000)'s narrative mediation model is introduced, justified, and translated into the context of RE.

Ma, Nan; Hall, Tracy; Barker, Trevor

316

Extensions to the time lag models for practical application to rocket engine stability design  

NASA Astrophysics Data System (ADS)

The combustion instability problem in liquid-propellant rocket engines (LREs) has remained a tremendous challenge since their discovery in the 1930s. Improvements are usually made in solving the combustion instability problem primarily using computational fluid dynamics (CFD) and also by testing demonstrator engines. Another approach is to use analytical models. Analytical models can be used such that design, redesign, or improvement of an engine system is feasible in a relatively short period of time. Improvements to the analytical models can greatly aid in design efforts. A thorough literature review is first conducted on liquid-propellant rocket engine (LRE) throttling. Throttling is usually studied in terms of vehicle descent or ballistic missile control however there are many other cases where throttling is important. It was found that combustion instabilities are one of a few major issues that occur during deep throttling (other major issues are heat transfer concerns, performance loss, and pump dynamics). In the past and again recently, gas injected into liquid propellants has shown to be a viable solution to throttle engines and to eliminate some forms of combustion instability. This review uncovered a clever solution that was used to eliminate a chug instability in the Common Extensible Cryogenic Engine (CECE), a modified RL10 engine. A separate review was also conducted on classic time lag combustion instability models. Several new stability models are developed by incorporating important features to the classic and contemporary models, which are commonly used in the aerospace rocket industry. The first two models are extensions of the original Crocco and Cheng concentrated combustion model with feed system contributions. A third new model is an extension to the Wenzel and Szuch double-time lag model also with feed system contributions. The first new model incorporates the appropriate injector acoustic boundary condition which is neglected in contemporary models. This new feature shows that the injector boundary can play a significant role for combustion stability, especially for gaseous injection systems or a system with an injector orifice on the order of the size of the chamber. The second new model additionally accounts for resistive effects. Advanced signal analysis techniques are used to extract frequency-dependent damping from a gas generator component data set. The damping values are then used in the new stability model to more accurately represent the chamber response of the component. The results show a more realistic representation of stability margin by incorporating the appropriate damping effects into the chamber response from data. The original Crocco model, a contemporary model, and the two new models are all compared and contrasted to a marginally stable test case showing their applicability. The model that incorporates resistive aspects shows the best comparison to the test data. Parametrics are also examined to show the influence of the new features and their applicability. The new features allow a more accurate representation of stability margin to be obtained. The third new model is an extension to the Wenzel and Szuch double-time lag chug model. The feed system chug model is extended to account for generic propellant flow rates. This model is also extended to incorporate aspects due to oxygen boiling and helium injection in the feed system. The solutions to the classic models, for the single-time lag and the double-time lag models, are often plotted on a practical engine operating map, however the models have presented some difficulties for numerical algorithms for several reasons. Closed-form solutions for use on these practical operating maps are formulated and developed. These models are incorporated in a graphical user interface tool and the new model is compared to an extensive data set. It correctly predicts the stability behavior at various operating conditions incorporating the influence of injected helium and boiling oxygen in the feed system.

Casiano, Matthew J.

317

EMS Models: Adaptation Of Engineering Design BlackBox Models For Use In TRIZ  

Microsoft Academic Search

The Theory of Inventive Problem Solving (TRIZ) has been widely recognized as a powerful systematic innovation technique that can be applied to a wide arrange of disciplines. This paper focuses on engineering design and illustrates how modeling methods already familiar to engineering designers can be adapted for use in TRIZ. Specifically, the 'black-box' modeling technique, common in problem formulation and

Madara Ogot

318

GTP-based integral real-3D spatial model for engineering excavation GIS  

Microsoft Academic Search

Engineering excavation GIS (E2 GIS) is a real-3D GIS serving for geosciences related to geo-engineering, civil engineering and mining engineering based\\u000a on generalized tri-prism (GTP) model. As two instances of GTP model, G-GTP is used for the real-3D modeling of subsurface\\u000a geological bodies, and E-GTP is used for the real-3D modeling of subsurface engineering excavations. In the light of the

Wu Lixin; Shi Wenzhong

2004-01-01

319

Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior  

NASA Astrophysics Data System (ADS)

Anomalous behavior of on-orbit spacecraft can often be detected using passive, remote sensors which measure electro-optical signatures that vary in time and spectral content. Analysts responsible for assessing spacecraft operational status and detecting detrimental anomalies using non-resolved imaging sensors are often presented with various sensing and identification issues. Modeling and measuring spacecraft self emission and reflected radiant intensity when the radiation patterns exhibit a time varying reflective glint superimposed on an underlying diffuse signal contribute to assessment of spacecraft behavior in two ways: (1) providing information on body component orientation and attitude; and, (2) detecting changes in surface material properties due to the space environment. Simple convex and cube-shaped spacecraft, designed to operate without protruding solar panel appendages, may require an enhanced level of preflight characterization to support interpretation of the various physical effects observed during on-orbit monitoring. This paper describes selected portions of the signature database generated using streamlined signature modeling and simulations of basic geometry shapes apparent to non-imaging sensors. With this database, summarization of key observable features for such shapes as spheres, cylinders, flat plates, cones, and cubes in specific spectral bands that include the visible, mid wave, and long wave infrared provide the analyst with input to the decision process algorithms contained in the overall sensing and identification architectures. The models typically utilize baseline materials such as Kapton, paints, aluminum surface end plates, and radiators, along with solar cell representations covering the cylindrical and side portions of the spacecraft. Multiple space and ground-based sensors are assumed to be located at key locations to describe the comprehensive multi-viewing aspect scenarios that can result in significant specular reflection from both the sun and the underlying earth surface. The objects are modeled to be either tumbling or spin stabilized at key orientations in order to capture the complexity of the solar/earth incident illumination and the sensor viewing aspect conditions. Although these geometries and processes appear to be specialized and limited, they are sufficient to capture the principal observable features that are necessary for gaining insight into the complex issues of interpreting non-imaging sensor signals for monitoring the actual on-orbit spacecraft behavior changes. This talk has been prepared as a poster paper, to allow for engagement with conference participants on the presentation contents, and discussions for expansion of the material to include additional topical areas for future work, as appropriate. All discussions have been limited only to topics that could be discussed in the open format of the conference.

Klem, B.; Swann, D.

2011-09-01

320

Hera: Engineering Web Applications Using Semantic Web-based Models  

NASA Astrophysics Data System (ADS)

In this chapter, we consider the contribution of models and model-driven approaches based on Semantic Web for the development of Web applications. The model-driven web engineering approach, that separates concerns on different abstraction level in the application design process, allows for more robust and structural design of web applications. This is illustrated by the use of Hera, an approach from the class of Web engineering methods that relies on models expressed using RDF(S) and an RDF(S) query language. It illustrates how models and in particular models that fit with the ideas and concepts from the Semantic Web allow to approach the design and engineering of modern, open and heterogeneous Web based systems. In the presented approach, adaptation and personalization are a main aspect and it is illustrated how they are expressed using semantic data models and languages. Also specific features of Hera are discussed, like interoperability between applications in user modeling, aspect orientation in Web design and graphical tool support for Web application design.

van der Sluijs, Kees; Houben, Geert-Jan; Leonardi, Erwin; Hidders, Jan

321

Diesel engine exhaust emission: oxidative behavior and microstructure of black smoke soot particulate.  

PubMed

Soot particulate collected from a Euro III heavy duty diesel engine run under black smoke conditions was investigated using thermogravimetry, transmission electron microscopy, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy. The characterization results are compared with those of commercial carbon black. The onset temperature toward oxidation of the diesel engine soot in 5% O2 is 150 degrees C lower than that for carbon black. The burn out temperature for the diesel engine soot is 60 degrees C lower than that of the carbon black. The soot primary particles exhibit a core-shell structure. The shell of the soot particles consists of homogeneously stacked basic structure units. The commercial carbon lamp black is more graphitized than the diesel engine soot, whereas the diesel engine soot contains more carbon in aromatic nature than the carbon black and is highly surface-functionalized. Our findings reveal that technical carbon black is not a suitable model for the chemistry of the diesel engine soot. PMID:16572780

Müller, J O; Su, D S; Jentoft, R E; Wild, U; Schlögl, R

2006-02-15

322

Engineered Barrier System Degradation, Flow, and Transport Process Model Report  

SciTech Connect

The Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is one of nine PMRs supporting the Total System Performance Assessment (TSPA) being developed by the Yucca Mountain Project for the Site Recommendation Report (SRR). The EBS PMR summarizes the development and abstraction of models for processes that govern the evolution of conditions within the emplacement drifts of a potential high-level nuclear waste repository at Yucca Mountain, Nye County, Nevada. Details of these individual models are documented in 23 supporting Analysis/Model Reports (AMRs). Nineteen of these AMRs are for process models, and the remaining 4 describe the abstraction of results for application in TSPA. The process models themselves cluster around four major topics: ''Water Distribution and Removal Model, Physical and Chemical Environment Model, Radionuclide Transport Model, and Multiscale Thermohydrologic Model''. One AMR (Engineered Barrier System-Features, Events, and Processes/Degradation Modes Analysis) summarizes the formal screening analysis used to select the Features, Events, and Processes (FEPs) included in TSPA and those excluded from further consideration. Performance of a potential Yucca Mountain high-level radioactive waste repository depends on both the natural barrier system (NBS) and the engineered barrier system (EBS) and on their interactions. Although the waste packages are generally considered as components of the EBS, the EBS as defined in the EBS PMR includes all engineered components outside the waste packages. The principal function of the EBS is to complement the geologic system in limiting the amount of water contacting nuclear waste. A number of alternatives were considered by the Project for different EBS designs that could provide better performance than the design analyzed for the Viability Assessment. The design concept selected was Enhanced Design Alternative II (EDA II).

E.L. Hardin

2000-07-17

323

Theoretical models of health behavior and workplace self-protective behavior  

Microsoft Academic Search

This paper provides a critical review of the applicability of theoretical models of health behavior to workplace self-protective behavior. Value-expectancy, environmental\\/contextual, and behavior change models are reviewed. On this basis, an integrative framework is proposed that conceptualizes self-protective behavior as consisting of four stages or phases: hazard appraisal, decision making, initiation, and adherence. In addition, five general constructs are identified

David M. DeJoy

1996-01-01

324

Genetically engineered mouse models of pancreatic adenocarcinoma.  

PubMed

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of human cancer for which there are no effective therapies. Deep sequencing of PDAC tumors has revealed the presence of a high number of mutations (>50) that affect at least a dozen key signaling pathways. This scenario highlights the urgent need to develop experimental models that faithfully reproduce the natural history of these human tumors in order to understand their biology and to design therapeutic approaches that might effectively interfere with their multiple mutated pathways. Over the last decade, several models, primarily based on the genetic activation of resident KRas oncogenes knocked-in within the endogenous KRas locus have been generated. These models faithfully reproduce the histological lesions that characterize human pancreatic tumors. Decoration of these models with additional mutations, primarily involving tumor suppressor loci known to be also mutated in human PDAC tumors, results in accelerated tumor progression and in the induction of invasive and metastatic malignancies. Mouse PDACs also display a desmoplastic stroma and inflammatory responses that closely resemble those observed in human patients. Interestingly, adult mice appear to be resistant to PDAC development unless the animals undergo pancreatic damage, mainly in the form of acute, chronic or even temporary pancreatitis. In this review, we describe the most representative models available to date and how their detailed characterization is allowing us to understand their cellular origin as well as the events involved in tumor progression. Moreover, their molecular dissection is starting to unveil novel therapeutic strategies that could be translated to the clinic in the very near future. PMID:23506980

Guerra, Carmen; Barbacid, Mariano

2013-02-11

325

Overview of heat transfer and fluid flow problem areas encountered in stirling engine modeling  

SciTech Connect

NASA Lewis Research Center has been managing Stirling engine development programs for over a decade. In addition to contractual programs, this work has included in-house engine testing and development of engine computer models. Attempts to validate Stirling engine computer models with test data have demonstrated that engine thermodynamic losses need better characterization. Various Stirling engine thermodynamic losses and efforts that are underway to characterize these losses are discussed.

Tew, R.C. Jr.

1988-02-01

326

Autoignition chemistry in a motored engine: An experimental and kinetic modeling study  

SciTech Connect

Autoignition of isomers of pentane, hexane, and primary reference fuel mixture of n-heptane and iso-octane has been studied experimentally under motored engine conditions and computationally using a detailed chemical kinetic reaction mechanism. Computed and experimental results are compared and used to help understand the chemical factors leading to engine knock in spark-ignited engines. The kinetic model reproduces observed variations in critical compression ratio with fuel molecular size and structure, provides intermediate product species concentrations in good agreement with observations, and gives insights into the kinetic origins of fuel octane sensitivity. Sequential computed engine cycles were found to lead to stable, non-igniting behavior for conditions below a critical compression ratio; to unstable, oscillating but nonigniting behavior in a transition region; and eventually to ignition as the compression ratio is steadily increased. This transition is related to conditions where a negative temperature coefficient of reaction exists, which has a significant influence on octane number and fuel octane sensitivity.

Curran, H.J.; Pitz, W.J.; Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States); Gaffuri, P. [Politecnico Milano, Milan (Italy). Chemical Engineerng Dept.; Leppard, W.R. [General Motors Research Lab., Warren, MI (United States)

1996-02-01

327

A cognitive-behavioral model of pathological Internet use  

Microsoft Academic Search

This article introduces a cognitive-behavioral model of Pathological Internet Use (PIU). While previous studies on Internet addiction have described behavioral factors, such as withdrawal and tolerance, the present article focuses on the maladaptive cognitions associated with PIU. The cognitive-behavioral model of PIU distinguishes between specific PIU and generalized PIU. Specific PIU refers to the condition in which an individual pathologically

R. A. Davis

2001-01-01

328

Rational models as theories – not standards – of behavior  

Microsoft Academic Search

When people's behavior in laboratory tasks systematically deviates from a rational model, the implication is that real-world performance could be improved by changing the behavior. However, recent studies suggest that behavioral violations of rational models are at least sometimes the result of strategies that are well adapted to the real world (and not necessarily to the laboratory task). Thus, even

Craig R. M. McKenzie

2003-01-01

329

Model-Based Systems Engineering Pilot Program at NASA Langley.  

National Technical Information Service (NTIS)

NASA Langley Research Center conducted a pilot program to evaluate the benefits of using a Model-Based Systems Engineering (MBSE) approach during the early phase of the Materials International Space Station Experiment-X (MISSE-X) project. The goal of the ...

D. G. Murphy K. G. Vipavetz S. I. Infeld

2012-01-01

330

Model Based Systems Engineering on the Europa mission concept study  

Microsoft Academic Search

At the start of 2011, the proposed Jupiter Europa Orbiter (JEO) mission was staffing up in expectation of becoming an official project later in the year for a launch in 2020. A unique aspect of the pre-project work was a strong emphasis and investment on the foundations of Model-Based Systems Engineering (MBSE). As so often happens in this business, plans

Todd J. Bayer; Seung Chung; Bjorn Cole; Brian Cooke; Frank Dekens; Chris Delp; I. Gontijo; Kari Lewis; Mehrdad Moshir; Robert Rasmussen; Dave Wagner

2012-01-01

331

A Classroom Model for WWW Use in Modern Engineering Education.  

ERIC Educational Resources Information Center

This paper describes the pilot project for a model of automatically generated customizable World Wide Web (WWW) sites for on-campus classes at the Graduate Department of Production and Systems Engineering, Federal University of Santa Catarina, Brazil. This project is being integrated into the department's STELA system, the first Brazilian Java and…

Barcia, Ricardo M.; Pacheco, Roberto; Paas, Leslie C.

332

A combustion kinetic model for estimating diesel engine NOx emissions  

Microsoft Academic Search

A phenomenological combustion model, which considers the space and time evolutions of a reacting diesel fuel jet, has been developed in order to estimate the instantaneous NOx concentration in a diesel engine cylinder from the start of the injection until the exhaust valve opening. The total injected fuel mass has been divided into different fuel packages, through the fuel injection

J. J. Hernandez; M. Lapuerta; J. Perez-Collado

2006-01-01

333

A compact simulation engine with flexible logic model expansion  

Microsoft Academic Search

A TASSE II (Timing and Strength Simulation Engine II) capable of simulating system-level logic circuits including memories and CPUs is presented. TASSE II processing units have been implemented on an extension board in a personal computer, and external logic models have been implemented on a separated board (20 cm×30 cm). The supporting software provides an integrated environment for logic simulation,

Naoaki SUGANUMA; Masahiro TOMITA; Kotaro HIRANO

1992-01-01

334

Numerical modeling of hydrogen-fueled internal combustion engines  

SciTech Connect

The planned use of hydrogen as the energy carrier of the future introduces new challenges and opportunities, especially to the engine design community. Hydrogen is a bio-friendly fuel that can be produced from renewable resources and has no carbon dioxide combustion products; and in a properly designed ICE, almost zero NO{sub x} and hydrocarbon emissions can be achieved. Because of the unique properties of hydrogen combustion - in particular the highly wrinkled nature of the laminar flame front due to the preferential diffusion instability - modeling approaches for hydrocarbon gaseous fuels are not generally applicable to hydrogen combustion. This paper reports on the current progress to develop a engine design capability based on KIVA family of codes for hydrogen-fueled, spark-ignited engines in support of the National Hydrogen Program. A turbulent combustion model, based on a modified eddy-turnover model in conjunction with an intake flow valve model, is found to describe well the efficiency and NO{sub x} emissions of this engine satisfy the Equivalent Zero Emission Vehicle (EZEV) standard established by the California Resource Board. 26 refs., 10 figs., 1 tab.

Johnson, N.L.; Amsden, A.A.

1996-12-31

335

A project interface buffering model for application engineer management  

Microsoft Academic Search

This work describes our proposed project interface buffering model (PIBM) which helps to reduce and smooth the many conflicting problems among system engineers, application programmers, system qualifier and system analysts who have participated in the IBM mainframe rightsizing project at National Taiwan University Hospital (NTUH). In fact, the PIBM can be used to relax or even solve the traditional conflict

P. H. Cheng; T. N. Chien; C. H. Chien; S. J. Chen; J. S. Lai

2004-01-01

336

Model Engine Performance Measurement From Force Balance Instrumentation.  

National Technical Information Service (NTIS)

A large scale model representative of a low-noise, high bypass ratio turbofan engine was tested for acoustics and performance in the NASA Lewis 9- by 15-Foot Low-Speed Wind Tunnel. This test was part of NASA's continuing Advanced Subsonic Technology Noise...

R. J. Jeracki

1998-01-01

337

Computer model of catalytic combustion/Stirling engine heater head  

NASA Astrophysics Data System (ADS)

The basic Acurex HET code was modified to analyze specific problems for Stirling engine heater head applications. Specifically, the code can model: an adiabatic catalytic monolith reactor, an externally cooled catalytic cylindrical reactor/flat plate reactor, a coannular tube radiatively cooled reactor, and a monolithic reactor radiating to upstream and downstream heat exchangers.

Chu, E. K.; Chang, R. L.; Tong, H.

1981-05-01

338

Computer model of catalytic combustion\\/Stirling engine heater head  

Microsoft Academic Search

The basic Acurex HET code was modified to analyze specific problems for Stirling engine heater head applications. Specifically, the code can model: an adiabatic catalytic monolith reactor, an externally cooled catalytic cylindrical reactor\\/flat plate reactor, a coannular tube radiatively cooled reactor, and a monolithic reactor radiating to upstream and downstream heat exchangers.

E. K. Chu; R. L. Chang; H. Tong

1981-01-01

339

Computer Modeling of Carbon Metabolism Enables Biofuel Engineering (Fact Sheet)  

SciTech Connect

In an effort to reduce the cost of biofuels, the National Renewable Energy Laboratory (NREL) has merged biochemistry with modern computing and mathematics. The result is a model of carbon metabolism that will help researchers understand and engineer the process of photosynthesis for optimal biofuel production.

Not Available

2011-09-01

340

Lean backstepping design for a jet engine compressor model  

Microsoft Academic Search

Backstepping offers flexibilities not present in other nonlinear design procedures. One of them is the possibility to avoid cancellation of useful nonlinearities. Such cancellations, which are common in feedback linearization designs, require large control effort and cause nonrobustness. As an illustration of a design that avoids cancellations we develop controllers for the Moore-Greitzer model of a jet engine compressor system.

M. Krstic; P. V. Kokotovic

1995-01-01

341

Genetically engineered mouse models and human osteosarcoma  

PubMed Central

Osteosarcoma is the most common form of bone cancer. Pivotal insight into the genes involved in human osteosarcoma has been provided by the study of rare familial cancer predisposition syndromes. Three kindreds stand out as predisposing to the development of osteosarcoma: Li-Fraumeni syndrome, familial retinoblastoma and RecQ helicase disorders, which include Rothmund-Thomson Syndrome in particular. These disorders have highlighted the important roles of P53 and RB respectively, in the development of osteosarcoma. The association of OS with RECQL4 mutations is apparent but the relevance of this to OS is uncertain as mutations in RECQL4 are not found in sporadic OS. Application of the knowledge or mutations of P53 and RB in familial and sporadic OS has enabled the development of tractable, highly penetrant murine models of OS. These models share many of the cardinal features associated with human osteosarcoma including, importantly, a high incidence of spontaneous metastasis. The recent development of these models has been a significant advance for efforts to improve our understanding of the genetics of human OS and, more critically, to provide a high-throughput genetically modifiable platform for preclinical evaluation of new therapeutics.

2012-01-01

342

Genetically engineered mouse models and human osteosarcoma.  

PubMed

Osteosarcoma is the most common form of bone cancer. Pivotal insight into the genes involved in human osteosarcoma has been provided by the study of rare familial cancer predisposition syndromes. Three kindreds stand out as predisposing to the development of osteosarcoma: Li-Fraumeni syndrome, familial retinoblastoma and RecQ helicase disorders, which include Rothmund-Thomson Syndrome in particular. These disorders have highlighted the important roles of P53 and RB respectively, in the development of osteosarcoma. The association of OS with RECQL4 mutations is apparent but the relevance of this to OS is uncertain as mutations in RECQL4 are not found in sporadic OS. Application of the knowledge or mutations of P53 and RB in familial and sporadic OS has enabled the development of tractable, highly penetrant murine models of OS. These models share many of the cardinal features associated with human osteosarcoma including, importantly, a high incidence of spontaneous metastasis. The recent development of these models has been a significant advance for efforts to improve our understanding of the genetics of human OS and, more critically, to provide a high-throughput genetically modifiable platform for preclinical evaluation of new therapeutics. PMID:23036272

Ng, Alvin Jm; Mutsaers, Anthony J; Baker, Emma K; Walkley, Carl R

2012-10-04

343

Using GOMS and Bayesian plan recognition to develop recognition models of operator behavior  

NASA Astrophysics Data System (ADS)

Trends in combat technology research point to an increasing role for uninhabited vehicles in modern warfare tactics. To support increased span of control over these vehicles human responsibilities need to be transformed from tedious, error-prone and cognition intensive operations into tasks that are more supervisory and manageable, even under intensely stressful conditions. The goal is to move away from only supporting human command of low-level system functions to intention-level human-system dialogue about the operator's tasks and situation. A critical element of this process is developing the means to identify when human operators need automated assistance and to identify what assistance they need. Toward this goal, we are developing an unmanned vehicle operator task recognition system that combines work in human behavior modeling and Bayesian plan recognition. Traditionally, human behavior models have been considered generative, meaning they describe all possible valid behaviors. Basing behavior recognition on models designed for behavior generation can offers advantages in improved model fidelity and reuse. It is not clear, however, how to reconcile the structural differences between behavior recognition and behavior modeling approaches. Our current work demonstrates that by pairing a cognitive psychology derived human behavior modeling approach, GOMS, with a Bayesian plan recognition engine, ASPRN, we can translate a behavior generation model into a recognition model. We will discuss the implications for using human performance models in this manner as well as suggest how this kind of modeling may be used to support the real-time control of multiple, uninhabited battlefield vehicles and other semi-autonomous systems.

Zaientz, Jack D.; DeKoven, Elyon; Piegdon, Nicholas; Wood, Scott D.; Huber, Marcus J.

2006-06-01

344

Comparison of Three Models for Predicting Altruistic Behavior  

ERIC Educational Resources Information Center

|This study compared three models for predicting altruistic behavior. The helping behavior (donating blood) of 251 undergraduate students was examined as a function of intention (model I), norms and ascription of responsibility (model II), and attitudes and self-monitoring (model III). (CM)|

Zuckerman, Miron; Reis, Harry T.

1978-01-01

345

Detailed Chemical Kinetic Modeling of Surrogate Fuels for Gasoline and Application to an HCCI Engine  

SciTech Connect

Gasoline consists of many different classes of hydrocarbons, such as paraffins, olefins, aromatics, and cycloalkanes. In this study, a surrogate gasoline reaction mechanism is developed, and it has one representative fuel constituent from each of these classes. These selected constituents are iso-octane, n-heptane, 1-pentene, toluene, and methyl-cyclohexane. The mechanism was developed in a step-wise fashion, adding submechanisms to treat each fuel component. Reactions important for low temperature oxidation (<1000K) and cross-reactions among different fuels are incorporated into the mechanism. The mechanism consists of 1214 species and 5401 reactions. A single-zone engine model is used to evaluate how well the mechanism captures autoignition behavior for conditions corresponding to homogeneous charge compression ignition (HCCI) engine operation. Experimental data are available for both how the combustion phasing changes with fueling at a constant intake temperature, and also how the intake temperature has to be changed with pressure in order to maintain combustion phasing for a fixed equivalence ratio. Three different surrogate fuel mixtures are used for the modeling. Predictions are in reasonably good agreement with the engine data. In addition, the heat release rate is calculated and compared to the data from experiments. The model predicts less low-temperature heat release than that measured. It is found that the low temperature heat-release rate depends strongly on engine speed, reactions of RO{sub 2}+HO{sub 2}, fuel composition, and pressure boost.

Naik, C V; Pitz, W J; Sj?berg, M; Dec, J E; Orme, J; Curran, H J; Simmie, J M; Westbrook, C K

2005-01-07

346

Stirling engine optimization using dimensionless Schmidt model  

NASA Astrophysics Data System (ADS)

The two- and five-parameter optimization with constraints is described based on the six-parameter dimensionless Schmidt model. The maximized criterion is cycle work per units of mean pressure pmean and total swept volume VT. Relative parameters are considered with three dead volumes and two swept volumes referred to VT. The optimization code based on the algorithm of conjugate gradient with projection on linear constraints is described. The optimal phase angle, optimal division of the swept volume, and optimal division of the dead volume are presented for various values of constraints imposed on temperature ratio and total or/and particular relative dead volumes.

Abenavoli, R. I.; Carlini, M.; Rudzinska, K.; Kormanski, H.

347

HCCI in a CFR engine: experiments and detailed kinetic modeling  

SciTech Connect

Single cylinder engine experiments and chemical kinetic modeling have been performed to study the effect of variations in fuel, equivalence ratio, and intake charge temperature on the start of combustion and the heat release rate. Neat propane and a fuel blend of 15% dimethyl-ether in methane have been studied. The results demonstrate the role of these parameters on the start of combustion, efficiency, imep, and emissions. Single zone kinetic modeling results show the trends consistent with the experimental results.

Flowers, D; Aceves, S; Smith, R; Torres, J; Girard, J; Dibble, R

1999-11-05

348

Premixed ignition behavior of C{sub 9} fatty acid esters: A motored engine study  

SciTech Connect

An experimental study on the premixed ignition behavior of C{sub 9} fatty acid esters has been conducted in a motored CFR engine. For each test fuel, the engine compression ratio was gradually increased from the lowest point (4.43) to the point where significant high temperature heat release (HTHR) was observed. The engine exhaust was sampled and analyzed through GC-FID/TCD and GC-MS. Combustion analysis showed that the four C{sub 9} fatty acid esters tested in this study exhibited evidently different ignition behavior. The magnitude of low temperature heat release (LTHR) follows the order, ethyl nonanoate > methyl nonanoate >> methyl 2-nonenoate > methyl 3-nonenoate. The lower oxidation reactivity for the unsaturated fatty acid esters in the low temperature regime can be explained by the reduced amount of six- or seven-membered transition state rings formed during the oxidation of the unsaturated esters due to the presence of a double bond in the aliphatic chain of the esters. The inhibition effect of the double bond on the low temperature oxidation reactivity of fatty acid esters becomes more pronounced as the double bond moves toward the central position of the aliphatic chain. GC-MS analysis of exhaust condensate collected under the engine conditions where only LTHR occurred showed that the alkyl chain of the saturated fatty acid esters participated in typical paraffin-like low temperature oxidation sequences. In contrast, for unsaturated fatty acid esters, the autoignition can undergo olefin ignition pathways. For all test compounds, the ester functional group remains largely intact during the early stage of oxidation. (author)

Zhang, Yu.; Yang, Yi; Boehman, Andre L. [EMS Energy Institute, The Pennsylvania State University, University Park, PA 16802 (United States)

2009-06-15

349

Modeling Human Behavior to Anticipate Insider Attacks  

SciTech Connect

The insider threat ranks among the most pressing cybersecurity challenges that threaten government and industry information infrastructures. To date, no systematic methods have been developed that provide a complete and effective approach to prevent data leakage, espionage and sabotage. Current practice is forensic in nature, relegating to the analyst the bulk of the responsibility to monitor, analyze, and correlate an overwhelming amount of data. We describe a predictive modeling framework that integrates a diverse set of data sources from the cyber domain as well as inferred psychological/motivational factors that may underlie malicious insider exploits. This comprehensive threat assessment approach provides automated support for the detection of high-risk behavioral “triggers” to help focus the analyst’s attention and inform the analysis. Designed to be domain independent, the system may be applied to many different threat and warning analysis/sensemaking problems.

Greitzer, Frank L.; Hohimer, Ryan E.

2011-06-09

350

Quantum critical behavior in a graphenelike model  

SciTech Connect

We present the results of numerical simulations of a (2+1)-dimensional fermion field theory based on a recent proposal for a model of graphene consisting of N{sub f} four-component Dirac fermions moving in the plane and interacting via an instantaneous Coulomb interaction. In the strong-coupling limit we identify a critical number of flavors N{sub fc}=4.8(2) separating an insulating from a conducting phase. This transition corresponds to the location of a quantum critical point, and we use a fit to the equation of state for the chiral order parameter to estimate the critical exponents. Next we simulate N{sub f}=2 corresponding to real graphene and approximately locate a transition from strong- to weak-coupling behavior. Strong correlations are evident in the weak-coupling regime.

Hands, Simon [Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP (United Kingdom); Strouthos, Costas [Department of Mechanical Engineering, University of Cyprus, Nicosia 1678 (Cyprus)

2008-10-15

351

System Modeling of Gas Engine Driven Heat Pump  

SciTech Connect

To improve the system performance of the GHP, modeling and experimental study has been made by using desiccant system in cooling operation (particularly in high humidity operations) and suction line waste heat recovery to augment heating capacity and efficiency. The performance of overall GHP system has been simulated by using ORNL Modulating Heat Pump Design Software, which is used to predict steady-state heating and cooling performance of variable-speed vapor compression air-to-air heat pumps for a wide range of operational variables. The modeling includes: (1) GHP cycle without any performance improvements (suction liquid heat exchange and heat recovery) as a baseline (both in cooling and heating mode), (2) the GHP cycle in cooling mode with desiccant system regenerated by waste heat from engine incorporated, (3) GHP cycle in heating mode with heat recovery (recovered heat from engine). According to the system modeling results, by using desiccant system regenerated by waste heat from engine, the SHR can be lowered to 40%. The waste heat of the gas engine can boost the space heating efficiency by 25% in rated operating conditions.

Mahderekal, Isaac [Oak Ridge National Laboratory (ORNL); Shen, Bo [ORNL; Vineyard, Edward [Oak Ridge National Laboratory (ORNL)

2012-01-01

352

Development of Systems Engineering Model for Spent Fuel Extraction Process  

SciTech Connect

The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV) is to establish a nuclear engineering test bed that can carry out effective transmutation and advanced reactor research and development effort. The Nevada Center for Advanced Computational Methods (NCACM) at UNLV is currently developing the systems engineering model, TRPSEMPro (Transmutation Research Program System Engineering Model Project, that provides process optimization through the automatic adjustment on input parameters, such as feed compositions, stages, flow rates, etc., based on the extraction efficiency of components and concerned output factors. An object-oriented programming (OOP) is considered. Such systems engineering model consists of task manager, task integration and solution monitor modules. A MS SQL server database is implemented for managing data flow from optimization processing. Task manager coordinates and interacts with other two modules. Task integration module works as a flowsheet constructor that builds task hierarchy, input parameter values and constrains. Task solution monitor component presents both in-progress and final outputs in tabulated and graphical formats. The system can monitor parameter justification outputs from optimization toolbox developed by Mathworks' MatLab commercial software. While initial parameter constraint identifications for using optimization process is tedious and time-consuming, the interface also provides a multiple-run process that executes a design matrix without invoking any optimization module. Experimental reports can be flexibly generated through database query and formatting. (authors)

Sun, Lijian; Royyuru, Haritha; Hsieh, Hsuan-Tsung 'Sean'; Chen, Yitung; Clarksean, Randy [Nevada Center for Advanced Computational Methods, College of Engineering, University of Nevada, Las Vegas, 4505 Maryland Parkway, Box 454027, Las Vegas, NV 89154-4027 (United States); Vandegrift, George; Copple, Jackie; Laidler, James [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

2004-07-01

353

Modeling and Validation of a Hydrogen Engine Powered Hybrid Electric Vehicle  

Microsoft Academic Search

This paper describes the modeling and validation of a hybrid electric vehicle powered by hydrogen internal- combustion engine. The engine was converted from a regular gasoline engine. The model of this vehicle was developed in PNGV Systems Analysis Toolkit (PSAT), which tracks engine flow and fuel usage within the vehicle powertrain and energy conversion components. The powertrain control strategy was

Xiaolai He; T. Maxwell; M. Parten

2007-01-01

354

The effect of tissue-engineered cartilage biomechanical and biochemical properties on its post-implantation mechanical behavior.  

PubMed

The insufficient load-bearing capacity of today's tissue-engineered (TE) cartilage limits its clinical application. Focus has been on engineering cartilage with enhanced mechanical stiffness by reproducing native biochemical compositions. More recently, depth dependency of the biochemical content and the collagen network architecture has gained interest. However, it is unknown whether the mechanical performance of TE cartilage would benefit more from higher content of biochemical compositions or from achieving an appropriate collagen organization. Furthermore, the relative synthesis rate of collagen and proteoglycans during the TE process may affect implant performance. Such insights would assist tissue engineers to focus on those aspects that are most important. The aim of the present study is therefore to elucidate the relative importance of implant ground substance stiffness, collagen content, and collagen architecture of the implant, as well as the synthesis rate of the biochemical constituents for the post-implantation mechanical behavior of the implant. We approach this by computing the post-implantation mechanical conditions using a composition-based fibril-reinforced poro-viscoelastic swelling model of the medial tibia plateau. Results show that adverse implant composition and ultrastructure may lead to post-implantation excessive mechanical loads, with collagen orientation being the most critical variable. In addition, we predict that a faster synthesis rate of proteoglycans compared to that of collagen during TE culture may result in excessive loads on collagen fibers post-implantation. This indicates that even with similar final contents, constructs may behave differently depending on their development. Considering these aspects may help to engineer TE cartilage implants with improved survival rates. PMID:22389193

Khoshgoftar, Mehdi; Wilson, Wouter; Ito, Keita; van Donkelaar, Corrinus C

2012-03-03

355

Applying Behavioral Model Systems to Landscape Ecology.  

National Technical Information Service (NTIS)

The author purposes that species may not necessarily be good surrogates for other species per se, but rather behavioral systems might be more appropriate for making comparison and predictions among species. Certain aspects of behavior, such as territorial...

J. O. Wolff

1997-01-01

356

Using the Information-Motivation Behavioral Model to Predict Sexual Behavior among Underserved Minority Youth  

ERIC Educational Resources Information Center

|Background: Testing, refining, and tailoring theoretical approaches that are hypothesized to reduce sexual risk behaviors among adolescent subpopulations is an important task. Relatively little is known about the relationship between components of the information-motivation-behavior (IMB) model and sexual behaviors among underage minority youth.…

Bazargan, Mohsen; Stein, Judith A.; Bazargan-Hejazi, Shahrzad; Hindman, David W.

2010-01-01

357

'Cobweb' Models Put to Work On Demand-Supply for Engineers.  

ERIC Educational Resources Information Center

|Explains how fluctuations of emphases in the economy, job market, and supply and demand for engineers, in the past decade have influenced enrollments in engineering schools, thus creating a cyclical behavior of boom and bust in enrollments, and in the engineering labor market. (GA)|

Sirbu, Marvin A., Jr.

1979-01-01

358

Enterprise Information System Engineering: A Model-Based Approach Based on the Zachman Framework  

Microsoft Academic Search

Enterprise information system engineering involves heterogeneous methodologies, tools and system models focusing on different system aspects, which should be integrated. Model-based system engineering may contribute towards this direction, by providing a central system model that captures system requirements and decisions that fulfill them at different levels of abstraction. The central system model serves all engineering activities and should be multi-layered,

Mara Nikolaidou; Nancy Alexopoulou

2008-01-01

359

Socialization Tactics, Proactive Behavior, and Newcomer Learning: Integrating Socialization Models  

ERIC Educational Resources Information Center

|The purpose of the study was to examine how socialization processes (socialization tactics and proactive behavior) jointly affect socialization content (i.e., what newcomers learn) and adjustment. Longitudinal survey data from 150 business and engineering graduates during their first 7 months of work indicate that: (1) institutionalized…

Ashforth, Blake E.; Sluss, David M.; Saks, Alan M.

2007-01-01

360

Mechanical behavior and constitutive modeling of metal cores  

Microsoft Academic Search

Studying the mechanical behavior of metal cores provides insight into the overall performance of struc- tures comprising metal sandwich plates, and can help immensely in designing metal sandwich plates for specific engineering applications. In this study, the response of folded (corrugated) plate and pyrami- dal truss cores are explored under both quasistatic and dynamic loadings. In particular, two important characteristics

Ashkan Vaziri; Zhenyu Xue

2007-01-01

361

Fuzzy modeling of system behavior for risk and reliability analysis  

Microsoft Academic Search

The main objective of the article is to permit the reliability analyst's\\/engineers\\/managers\\/practitioners to analyze the failure behavior of a system in a more consistent and logical manner. To this effect, the authors propose a methodological and structured framework, which makes use of both qualitative and quantitative techniques for risk and reliability analysis of the system. The framework has been applied

Rajiv Kumar Sharma; Dinesh Kumar; Pradeep Kumar

2008-01-01

362

Elastic behavior of corrugated cardboard: experiments and modeling  

Microsoft Academic Search

Motivated by computed homogeneous of linear corrugated cardboard behavior, an analytical model related to the assessment of equals behavior is proposed. This model takes into account the geometrical and mechanical properties of the corrugated cardboard constituents. An experimental methodology is also proposed to obtain both the in-plane elastic properties of each constituents and the corrugated cardboard. After model validation by

Z. Aboura; N. Talbi; S. Allaoui; M. L. Benzeggagh

2004-01-01

363

Cognitive-Operative Model of Intelligent Learning Systems Behavior  

ERIC Educational Resources Information Center

In this paper behavior during the teaching-learning process is modeled by means of a fuzzy cognitive map. The elements used to model such behavior are part of a generic didactic model, which emphasizes the use of cognitive and operative strategies as part of the student-tutor interaction. Examples of possible initial scenarios for the…

Laureano-Cruces, Ana Lilia; Ramirez-Rodriguez, Javier; Mora-Torres, Martha; de Arriaga, Fernando; Escarela-Perez, Rafael

2010-01-01

364

Parental Monitoring Behaviors: A Model of Rules, Supervision, and Conflict  

ERIC Educational Resources Information Center

|A model of parental monitoring behaviors, comprising rule setting and supervision, was proposed. The hypothesized relationship between rules, supervision, conflict, and adolescent problem behavior was tested using structured equation modeling on self-report data from 1,285 adolescents aged 14 to 15 years. The model was an adequate fit of the…

Hayes, Louise; Hudson, Alan; Matthews, Jan

2004-01-01

365

Aging behavior of polymeric solar absorber materials - Part 1: Engineering plastics  

SciTech Connect

In this series of two papers, various polymeric materials are investigated as to their potential applicability as absorber materials for solar thermal collectors. The focus of the investigation is to study the aging behavior of these materials under maximum operating conditions (80 C in water up to 16,000 h) and stagnation conditions (140 C in air up to 500 h) typical for northern climate. The materials supplied or produced as polymer films were first characterized in the unaged state and then for different states of aging by differential scanning calorimetry (DSC), by size exclusion chromatography (SEC) and by mechanical tensile tests. Physical aging phenomena were studied by DSC, SEC analysis provided information on chemical degradation of the materials. In addition, physical and chemical aging were both analyzed via the small and large strain mechanical behavior. While the present Part 1 of this paper series deals with the aging behavior of engineering plastics, including two amorphous polymers (a polyphenylene ether polystyrene blend (PPE + PS) and polycarbonate (PC)) and two semi-crystalline polymers (two types of polyamide 12 (PA12)), the aging behavior of so-called ''commodity'' plastics (PE and PP) is the subject of Part 2. Comparing the two aging conditions, the amorphous materials (PPE + PS and PC) turned out to be more prone to physical and chemical aging at 140 C in air. In contrast, the semi-crystalline PA12 materials were more strongly affected by exposure to water at 80 C, although to different degrees, depending on the modification. (author)

Kahlen, S. [Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, Leoben 8700 (Austria); Wallner, G.M.; Lang, R.W. [Institute for Polymeric Materials and Testing, University of Linz, Altenbergerstrasse 69, Linz 4040 (Austria)

2010-09-15

366

Kinetic Modeling of Gasoline Surrogate Components and Mixtures under Engine Conditions  

SciTech Connect

Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, an improved version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multicomponent gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines (3-50 atm, 650-1200K, stoichiometric fuel/air mixtures). Simulation results are discussed focusing attention on the mixing effects of the fuel components.

Mehl, M; Pitz, W J; Westbrook, C K; Curran, H J

2010-01-11

367

Reverse-engineering a watermark detector based on a more precise model  

NASA Astrophysics Data System (ADS)

Detection results obtained from an oracle can be used to reverse-engineer the underlying detector structure, or parameters thereof. In particular, if a detector uses a common structure like correlation or normalized correlation, detection results can be used to estimate feature space dimensionality, watermark strength, and detector threshold values. Previous estimation techniques used a simplistic but tractable model for a watermarked image in the detection cone of a normalized correlation detector; in particular a watermarked image is assumed to lie along the axis of the detection cone, essentially corresponding to an image of zero magnitude. This produced useful results for feature spaces of fewer dimensions, but increasingly imprecise estimates for larger feature spaces. In this paper we model the watermarked image properly as a sum of a cover vector and approximately orthogonal watermark vector, offsetting the image within the cone, which is the geometry of a detector using normalized correlation. This symmetry breaking produces a far more complex model which boils down to a quartic equation. Although it is infeasible to find its symbolic solution even with the aid of computer, our numerical analysis results show certain critical behavior which reveals the relationship between the attacking noise strength and the detector parameters. The critical behavior predicted by our model extends our reverse-engineering capability to the case of detectors with large feature space dimensions, which is not uncommon in multimedia watermarking algorithms.

Yu, Jun; Craver, Scott

2010-02-01

368

Minimal model of a heat engine: information theory approach.  

PubMed

We construct a generic model for a heat engine using information theory concepts, attributing irreversible energy dissipation to the information transmission channels. Using several forms for the channel capacity, classical and quantum, we demonstrate that our model recovers both the Carnot principle in the reversible limit, and the universal maximum power efficiency expression of nonreversible thermodynamics in the linear response regime. We expect the model to be very useful as a testbed for studying fundamental topics in thermodynamics, and for providing new insights into the relationship between information theory and actual thermal devices. PMID:20866578

Zhou, Yun; Segal, Dvira

2010-07-15

369

A Meta-Analytic Review of Behavior Modeling Training  

Microsoft Academic Search

A meta-analysis of 117 studies evaluated the effects of behavior modeling training (BMT) on 6 training outcomes, across characteristics of training design. BMT effects were largest for learning outcomes, smaller for job behavior, and smaller still for results outcomes. Although BMT effects on declarative knowledge decayed over time, training effects on skills and job behavior remained stable or even increased.

Paul J. Taylor; Darlene F. Russ-Eft; Daniel W. L. Chan

2005-01-01

370

Simulation and Modeling of Group Behavior during Emergency Evacuation  

Microsoft Academic Search

Modeling group behavior is very critical in the context of simulations designed for training personals or evacuation decision making strategies. The behavior of agents in such simulations plays a very important role. Agent behavior in complex environments such as emergency evacuation scenario involves collaboration with other agents. A simple example can be a group of people in a building trying

Sharad Sharma

2009-01-01

371

Interoperation of DEVS models and differential equation models using HLA\\/RTI: hybrid simulation of engineering and engagement level models  

Microsoft Academic Search

A hybrid model is a combination of models developed in various simulation development environments. A war game model is a kind of hybrid model and consists of multiple level models. Engineering level models are interested in the change of values via time and process mathematical equations, and most of them are developed in MALTAB\\/Simulink. Engage- ment level models are concerned

Chang Ho Sung; Jeong-hee Hong; Tag Gon Kim

2009-01-01

372

Phase behavior of model ABC triblock copolymers  

NASA Astrophysics Data System (ADS)

The phase behavior of poly(isoprene-b-styrene- b-ethylene oxide) (ISO), a model ABC triblock copolymer has been studied. This class of materials exhibit self-assembly, forming a large array of ordered morphologies at length scales of 5-100 nm. The formation of stable three-dimensionally continuous network morphologies is of special interest in this study. Since these nanostructures considerably impact the material properties, fundamental knowledge for designing ABC systems have high technological importance for realizing applications in the areas of nanofabrication, nanoporous media, separation membranes, drug delivery and high surface area catalysts. A comprehensive framework was developed to describe the phase behavior of the ISO triblock copolymers at weak to intermediate segregation strengths spanning a wide range of composition. Phases were characterized through a combination of characterization techniques, including small angle x-ray scattering, dynamic mechanical spectroscopy, transmission electron microscopy, and birefringence measurements. Combined with previous investigations on ISO, six different stable ordered state symmetries have been identified: lamellae (LAM), Fddd orthorhombic network (O70), double gyroid (Q230), alternating gyroid (Q214), hexagonal (HEX), and body-centered cubic (BCC). The phase map was found to be somewhat asymmetric around the fI = fO isopleth. This work provides a guide for theoretical studies and gives insight into the intricate effects of various parameters on the self-assembly of ABC triblock copolymers. Experimental SAXS data evaluated with a simple scattering intensity model show that local mixing varies continuously across the phase map between states of two- and three-domain segregation. Strategies of blending homopolymers with ISO triblock copolymer were employed for studying the swelling properties of a lamellar state. Results demonstrate that lamellar domains swell or shrink depending upon the type of homopolymer that was mixed. The results provide insight into the chain conformation of ABC triblock copolymers, where the B blocks are completely bridged across the adjacent A and C domains. In the final part of the thesis, the swelling properties were used to study the directed assembly of ABC triblock copolymers on chemically nanopatterned surfaces.

Chatterjee, Joon

373

Advanced modeling of active control of fan noise for ultra high bypass turbofan engines  

NASA Astrophysics Data System (ADS)

An advanced model of active control of fan noise for ultra high bypass turbofan engines has been developed. This model is based on a boundary integral equation method and simulates the propagation, radiation and control of the noise generated by an engine fan surrounded by a duct of finite length and cylindrical shape, placed in a uniform flow. Control sources, modeled by point monopoles placed along the wall of the engine inlet or outlet duct, inject anti-noise into the duct to destructively interfere with the sound field generated by the fan. The duct inner wall can be lined or rigid. Unlike current methods, reflection from the duct openings is taken into account, as well as the presence of the evanescent modes. Forward, as well as backward (i.e., from the rear of the engine), external radiation is computed. The development of analytical expressions for the sound field resulting from both the fan loading noise and the control sources is presented. Two fan models are described. The first model uses spinning line sources with radially distributed strength to model the loading force that the fan blades exert on the medium. The second model uses radial arrays of spinning point dipoles to simulate the generation of fan modes of specific modal amplitudes. It is shown that these fan models can provide a reasonable approximation of actual engine fan noise in the instance when the modal amplitude of the propagating modes or the loading force distribution on the fan blades, is known. Sample cases of active noise control are performed to demonstrate the feasibility of the model. The results from these tests indicate that this model (1)is conducive to more realistic studies of active control of fan noise on ultra high bypass turbofan engines because it accounts for the presence of evanescent modes and for interference between inlet and outlet radiation, which were shown to have some impact on the performance of the active control system; (2)is very useful because it allows monitoring of any region of the acoustic field; (3)is computationally fast, and therefore suitable to conduct parametric studies. Finally, the potential that active noise control techniques have for reducing fan noise on an ultra high bypass turbofan engine is investigated. Feedforward control algorithms are simulated. Pure active control techniques, as well as hybrid (active/passive) control techniques, are studied. It is demonstrated that active noise control has the potential to reduce substantially, and over a relatively large far field sector, the fan noise radiated by an ultra high bypass turbofan engine. It is also shown that a hybrid control system can achieve significantly better levels of noise reduction than a pure passive or pure active control system, and that its optimum solution is more robust than the one achieved with a pure active control system. The model has shown to realistically predict engine acoustic behavior and is thus likely to be a very useful tool for designing active noise control systems for ultra high bypass turbofan engines.

Hutcheson, Florence Vanel

1999-11-01

374

Modeling and optimization of a typical fuel cell–heat engine hybrid system and its parametric design criteria  

Microsoft Academic Search

A theoretical modeling approach is presented, which describes the behavior of a typical fuel cell–heat engine hybrid system in steady-state operating condition based on an existing solid oxide fuel cell model, to provide useful fundamental design characteristics as well as potential critical problems. The different sources of irreversible losses, such as the electrochemical reaction, electric resistances, finite-rate heat transfer between

Yingru Zhao; Jincan Chen

2009-01-01

375

Engineering models for catastrophe risk and their application to insurance  

NASA Astrophysics Data System (ADS)

Internationally earthquake insurance, like all other insurance (fire, auto), adopted actuarial approach in the past, which is, based on historical loss experience to determine insurance rate. Due to the fact that earthquake is a rare event with severe consequence, irrational determination of premium rate and lack of understanding scale of potential loss led to many insurance companies insolvent after Northridge earthquake in 1994. Along with recent advances in earth science, computer science and engineering, computerized loss estimation methodologies based on first principles have been developed to the point that losses from destructive earthquakes can be quantified with reasonable accuracy using scientific modeling techniques. This paper intends to introduce how engineering models can assist to quantify earthquake risk and how insurance industry can use this information to manage their risk in the United States and abroad.

Dong, Weimin

2002-06-01

376

Long Term Oxidation of Model and Engineering TiAl Alloys  

SciTech Connect

The purpose of this research was to characterize the oxidation behavior of several model (TiAl, TiAl-Nb, TiAl-Cr, TiAl-Cr-Nb) and engineering alloys (XD, K5, Alloy 7, WMS) after long-term isothermal exposure ({approx}7000 h) at 704 C, and after shorter time exposure ({approx}1000 h) at 800 C in air. High-resolution field emission and microprobe scanning electron microscopy were used to characterize the scales formed on these alloys. Similarities and differences observed in the scales are correlated with the various ternary and quaternary microalloying additions.

Locci, IE

2001-08-24

377

Aspect-Oriented Model-Driven Software Product Line Engineering  

NASA Astrophysics Data System (ADS)

Software product line engineering aims to reduce development time, effort, cost, and complexity by taking advantage of the commonality within a portfolio of similar products. The effectiveness of a software product line approach directly depends on how well feature variability within the portfolio is implemented and managed throughout the development lifecycle, from early analysis through maintenance and evolution. This article presents an approach that facilitates variability implementation, management, and tracing by integrating model-driven and aspect-oriented software development. Features are separated in models and composed of aspect-oriented composition techniques on model level. Model transformations support the transition from problem to solution space models. Aspect-oriented techniques enable the explicit expression and modularization of variability on model, template, and code level. The presented concepts are illustrated with a case study of a home automation system.

Groher, Iris; Voelter, Markus

378

Enhancing the Behavioral Fidelity of Synthetic Entities with Human Behavior Models.  

National Technical Information Service (NTIS)

Human-behavior models (HBMs) and artificial intelligence systems are called on to fill a wide variety of roles in military simulations. Each of the 'off the shelf' human behavior models available today focuses on a specific area of human cognition and beh...

B. G. Silverman K. O'Brien M. V. Lent P. Probst R. McAlinden

2004-01-01

379

Measurements in a motored four-stroke reciprocating model engine  

Microsoft Academic Search

Measurements of ensemble-averaged axial velocities and the rms of the corresponding fluctuations obtained by laser Doppler anemometry are reported for the axisymmetric flow in a four-stoke model engine motored at 200 rpm with a compression ratio of 3.5. The flow structure during the intake stroke is dominated by the inlet geometry conditions with small dependence on whether compression is applied

C. Arcoumanis; A. F. Bicen; J. H. Whitelaw

1981-01-01

380

Organization of kerosene combustion in a model hypersonic ramjet engine  

Microsoft Academic Search

We present the results of experiments on the organization of kerosene combustion in a two-dimensional model of a hypersonic ramjet engine in conditions of external blow-out by a flow with parameters M8=6, p8*=(53–55)·105 Pa, T8*=1500 K. We studied the operation of some variants of a rectangular combustion chamber with different kerosine injectors and stabilizing elements when hydrogen is used as

V. A. Vinogradov; S. A. Kobyzhskii; M. D. Petrov

1992-01-01

381

Application of Advanced Model-Driven Techniques in Performance Engineering  

Microsoft Academic Search

\\u000a Software performance engineering supports software architects to identify potential performance problems, such as bottlenecks,\\u000a in their software systems during the design phase. In such early stages of the software life-cycle, only little information\\u000a is available about the system’s implementation and execution environment. However, these details are crucial for accurate\\u000a performance predictions. Performance completions close the gap between available high-level models

Lucia Kapová; Ralf Reussner

2010-01-01

382

Generating Phenotypical Erroneous Human Behavior to Evaluate Human-automation Interaction Using Model Checking.  

PubMed

Breakdowns in complex systems often occur as a result of system elements interacting in unanticipated ways. In systems with human operators, human-automation interaction associated with both normative and erroneous human behavior can contribute to such failures. Model-driven design and analysis techniques provide engineers with formal methods tools and techniques capable of evaluating how human behavior can contribute to system failures. This paper presents a novel method for automatically generating task analytic models encompassing both normative and erroneous human behavior from normative task models. The generated erroneous behavior is capable of replicating Hollnagel's zero-order phenotypes of erroneous action for omissions, jumps, repetitions, and intrusions. Multiple phenotypical acts can occur in sequence, thus allowing for the generation of higher order phenotypes. The task behavior model pattern capable of generating erroneous behavior can be integrated into a formal system model so that system safety properties can be formally verified with a model checker. This allows analysts to prove that a human-automation interactive system (as represented by the model) will or will not satisfy safety properties with both normative and generated erroneous human behavior. We present benchmarks related to the size of the statespace and verification time of models to show how the erroneous human behavior generation process scales. We demonstrate the method with a case study: the operation of a radiation therapy machine. A potential problem resulting from a generated erroneous human action is discovered. A design intervention is presented which prevents this problem from occurring. We discuss how our method could be used to evaluate larger applications and recommend future paths of development. PMID:23105914

Bolton, Matthew L; Bass, Ellen J; Siminiceanu, Radu I

2012-11-01

383

Generating Phenotypical Erroneous Human Behavior to Evaluate Human-automation Interaction Using Model Checking  

PubMed Central

Breakdowns in complex systems often occur as a result of system elements interacting in unanticipated ways. In systems with human operators, human-automation interaction associated with both normative and erroneous human behavior can contribute to such failures. Model-driven design and analysis techniques provide engineers with formal methods tools and techniques capable of evaluating how human behavior can contribute to system failures. This paper presents a novel method for automatically generating task analytic models encompassing both normative and erroneous human behavior from normative task models. The generated erroneous behavior is capable of replicating Hollnagel’s zero-order phenotypes of erroneous action for omissions, jumps, repetitions, and intrusions. Multiple phenotypical acts can occur in sequence, thus allowing for the generation of higher order phenotypes. The task behavior model pattern capable of generating erroneous behavior can be integrated into a formal system model so that system safety properties can be formally verified with a model checker. This allows analysts to prove that a human-automation interactive system (as represented by the model) will or will not satisfy safety properties with both normative and generated erroneous human behavior. We present benchmarks related to the size of the statespace and verification time of models to show how the erroneous human behavior generation process scales. We demonstrate the method with a case study: the operation of a radiation therapy machine. A potential problem resulting from a generated erroneous human action is discovered. A design intervention is presented which prevents this problem from occurring. We discuss how our method could be used to evaluate larger applications and recommend future paths of development.

Bolton, Matthew L.; Bass, Ellen J.; Siminiceanu, Radu I.

2012-01-01

384

76 FR 56637 - Airworthiness Directives; Lycoming Engines Model IO-720-A1B Reciprocating Engines  

Federal Register 2010, 2011, 2012, 2013

...issuing this AD to prevent engine crankshaft failure and damage to the airplane...corrected, could result in engine crankshaft failure and damage to the airplane...issuing this AD to prevent engine crankshaft failure and damage to the...

2011-09-14

385

76 FR 44245 - Special Conditions: Gulfstream Model GVI Airplane; Limit Engine Torque Loads for Sudden Engine...  

Federal Register 2010, 2011, 2012, 2013

...which addresses loads imposed by engine seizure, was adopted in 1965. Worst case engine seizure events have become increasingly more severe...subject to certain rare-but-severe engine seizure events. Service history shows that...

2011-07-25

386

Injection engine as a control object. I. Schematic diagram of the engine and synthesis of a mathematical model  

Microsoft Academic Search

The paper is devoted to the analysis of injection engine as an object of automatic control by a built-in microprocessor system.\\u000a The schematic diagram of the engine is presented; controlled, measured, and input variables are indicated; a mathematical\\u000a model of the engine oriented to the use in analysis and synthesis of control systems is described. Transient processes and\\u000a static characteristics

D. N. Gerasimov; H. Javaherian; D. V. Efimov; V. O. Nikiforov

2010-01-01

387

Review of multi-fuel engine concepts and numerical modeling of in-cylinder flow processes in direct injection engines  

Microsoft Academic Search

The paper reviews the literature for methods of increasing fuel flexibility in diesel engines over a range of fuel properties representing alcohols to high viscosity diesels. It was conceived that the details of fuel-charge within the engine cylinder would help evaluate the requirements for multi-fuel engine design. It is therefore, attempted to model in-cylinder flows, fuel-air mixing and fuel property

V. K. Duggal; T. W. Kuo; F. B. Lux

1984-01-01

388

Theory development for HIV behavioral health: empirical validation of behavior health models specific to HIV risk  

PubMed Central

In the presence of numerous health behavior theories, it is difficult to determine which of the many theories is most precise in explaining health-related behavior. New models continue to be introduced to the field, despite already existing disparity, overlap, and lack of unification among health promotion theories. This paper will provide an overview of current arguments and frameworks for testing and developing a comprehensive set of health behavior theories. In addition, the authors make a unique contribution to the HIV health behavior theory literature by moving beyond current health behavior theory critiques to argue that one of the field’s preexisting, but less popular theories, Social Action Theory (SAT), offers a pragmatic and broad framework to address many of the accuracy issues within HIV health behavior theory. The authors conclude this article by offering a comprehensive plan for validating model accuracy, variable influence, and behavioral applicability of SAT.

Traube, Dorian E.; Holloway, Ian W.; Smith, Lana

2011-01-01

389

Can health promotion model constructs predict nutritional behavior among diabetic patients?  

PubMed Central

Since, the nutritional behavior is a complicated process in which various factors play the role, this study aimed at specifying the effective factors in nutritional behavior of diabetic patients based on Health Promotion Model. This paper reviews the published articles from 2000 to the beginning of 2012, using the various data banks and search engines such as PubMed, ProQuest, Scopus, Elsevier, and the key words" perceived benefits and barriers, perceived self-efficacy, social support, activity related affect, situational influences, commitment to plan of action, immediate competing demands and diabetes, self-caring and diabetes. Unfavorable self-care situation especially, inappropriate nutritional behavior is related to some effective modifiable factors. Perceived benefits and self-efficacy regarding behaviors play a major role in the nutritional behaviors. Social support especially, spouses’ support has a significant role in this regard. Moreover, there is a reverse relationship between perceived barriers and nutritional self-care. In addition, behavioral feelings, situational influences, commitment to plan of action and immediate competing demands and preferences can also impact and overshadow the nutritional self-care. Following the relationship between constructs of Health Promotion Model and nutritional behavior the constructs of this model can be utilized as the basis for educational intervention among diabetes.

Mohebi, Siamak; Sharifirad, Ghlamreza; Feizi, Avat; Botlani, Saeedeh; Hozori, Mohammad; Azadbakht, Leila

2013-01-01

390

Modeling pedestrian crowd behavior based on a cognitive model of social comparison theory  

Microsoft Academic Search

Modeling crowd behavior is an important challenge for cognitive modelers. Models of crowd behavior facilitate analysis and\\u000a prediction of human group behavior, where people are close geographically or logically, and are affected by each other’s presence\\u000a and actions. Existing models of crowd behavior, in a variety of fields, leave many open challenges. In particular, psychology\\u000a models often offer only qualitative

Natalie Fridman; Gal A. Kaminka

2010-01-01

391

Transitioning a model-based software engineering architectural style to Ada 95  

Microsoft Academic Search

Model-Based Software Engineering (MBSE) is a disciplined engineering approach that relies on constructing models of software applications in a product family to achieve the benefits of reuse, shorter time to market, and higher quality. The models provide the necessary information to support, economicaIly and effectively, future changes to a software product family. MBSE relies upon proven domain analysis and engineering

Anthony Gargaro; A. Spencer Peterson

1995-01-01

392

REAL TIME ENGINE MODEL IMPLEMENTATION FOR ADAPTIVE CONTROL & PERFORMANCE MONITORING OF LARGE CIVIL TURBOFANS  

Microsoft Academic Search

A real time engine model to be used as an onboard observer in Large Civil Turbofans has been developed. The main features of this Real Time Model are its non-linear physical structure (identical with a detailed transient model, which may represent the real engine) as well as its ability to adapt itself to the engine condition. General and specific requirements

A. Stamatis; K. Mathioudakis; J. Ruiz; B. Curnock

393

A five-year working model for integrating design into the engineering curriculum  

Microsoft Academic Search

We discuss a five-year working model for integrating design into the Manufacturing Engineering Department's curriculum at Miami University. The model builds on work from other engineering institutions and coalitions as well as our own unique experience at Miami University. Our model consists of unified threads among the engineering science, manufacturing and design courses in the curriculum. These threads allow the

James B. Stenger; Osama Ettouney

1996-01-01

394

Development of global mixing, combustion, and ignition models for quiescent chamber direct-injection diesel engines  

Microsoft Academic Search

A large scale mixing and combustion model has been developed and studied through testing of two separate direct injection diesel engines. As a corollary, a shear layer ignition model was also developed for estimating the effects of key engine-related parameters on autoignition. Both models were developed for eventual inclusion into an engine cycle simulation for studying the effect of various

Peter Joseph Schihl

1998-01-01

395

Diesel engine emissions and combustion predictions using advanced mixing models applicable to fuel sprays  

Microsoft Academic Search

An advanced mixing model was applied to study engine emissions and combustion with different injection strategies ranging from multiple injections, early injection and grouped-hole nozzle injection in light and heavy duty diesel engines. The model was implemented in the KIVA-CHEMKIN engine combustion code and simulations were conducted at different mesh resolutions. The model was compared with the standard KIVA spray

Neerav Abani; Rolf D. Reitz

2010-01-01

396

WEP: A Reference Model and the Portal of Web Engineering Resources  

Microsoft Academic Search

This paper introduces the Web Engineering Resources Portal (shortly WEP), as a basic Reference Model and Guide for the Web Engineers. WEP provides a general classification of Web Engineering Resources under tech- nologies, research results and tools. It consists of a Reference Model and a Re- sources Portal. The objective of WEP Reference Model is to provide a common basic

Sotiris Christodoulou; Theodore Papatheodorou

2004-01-01

397

Model-based diagnosis of an automotive engine using several types of fault models  

Microsoft Academic Search

Automotive engines is an important application for model-based diagnosis because of legislative regulations. A diagnosis system for the air-intake system of a turbo-charged engine is constructed. The design is made in a systematic way and follows a framework of hypothesis testing. Different types of sensor faults and leakages are considered. It is shown how many different types of fault models,

Mattias Nyberg

2002-01-01

398

Reverse Engineering Boolean Networks: From Bernoulli Mixture Models to Rule Based Systems  

PubMed Central

A Boolean network is a graphical model for representing and analyzing the behavior of gene regulatory networks (GRN). In this context, the accurate and efficient reconstruction of a Boolean network is essential for understanding the gene regulation mechanism and the complex relations that exist therein. In this paper we introduce an elegant and efficient algorithm for the reverse engineering of Boolean networks from a time series of multivariate binary data corresponding to gene expression data. We call our method ReBMM, i.e., reverse engineering based on Bernoulli mixture models. The time complexity of most of the existing reverse engineering techniques is quite high and depends upon the indegree of a node in the network. Due to the high complexity of these methods, they can only be applied to sparsely connected networks of small sizes. ReBMM has a time complexity factor, which is independent of the indegree of a node and is quadratic in the number of nodes in the network, a big improvement over other techniques and yet there is little or no compromise in accuracy. We have tested ReBMM on a number of artificial datasets along with simulated data derived from a plant signaling network. We also used this method to reconstruct a network from real experimental observations of microarray data of the yeast cell cycle. Our method provides a natural framework for generating rules from a probabilistic model. It is simple, intuitive and illustrates excellent empirical results.

Saeed, Mehreen; Ijaz, Maliha; Javed, Kashif; Babri, Haroon Atique

2012-01-01

399

Predicting Exercise Behavior Among Iranian College Students Using the Transtheoretical Model and Structural Equation Modeling  

Microsoft Academic Search

Despite the many benefits of exercise behavior, physical inactivity is a global health issue. Evaluating the efficacy of behavior change models and identifying the factors that influence exercise behavior in various populations is clearly a research priority. The Transtheoretical Model (TTM) is a dynamic approach to understanding exercise and physical activity behavior. The purpose of this study was to determine

Rabiollah Farmanbar; Shamsaddin Niknami; Alireza Heydarnia

400

Modeling user posting behavior on social media  

Microsoft Academic Search

User generated content is the basic element of social media websites. Relatively few studies have systematically analyzed the motivation to create and share content, especially from the perspective of a common user. In this paper, we perform a comprehensive analysis of user posting behavior on a popular social media website, Twitter. Specifically, we assume that user behavior is mainly influenced

Zhiheng Xu; Yang Zhang; Yao Wu; Qing Yang

2012-01-01

401

The Impact of Modelling and Simulation Technology on Engineering Problem Solving  

Microsoft Academic Search

The paper focuses on the use of modelling and simulation technology in the design and development of engineering projects. Using case studies, the authors examine the experiences of engineers and designers working with these tools. The paper provides insights into how this technology is reshaping the way engineers work and solve problems. Engineering design remains a highly uncertain activity and

Mark Dodgson; David M. Gann; Ammon Salter

2007-01-01

402

Modeling and laser-based sensing of pulsed detonation engines  

NASA Astrophysics Data System (ADS)

This work is concerned with two major aspects of pulse detonation engines (PDE) research: modeling and laser-based sensing. The modeling addresses both ideal and real considerations relevant to PDE design. First, an ideal nozzle model is developed which provides a tool for choosing area ratios for fixed-geometry converging, diverging, or converging-diverging nozzles. Next, losses associated with finite-rate chemistry are investigated. It was found that PDEs can experience up to 10% reduction in specific impulse from this effect if 02 is used as the oxidizer, whereas the losses are negligible for air-breathing applications. Next, heat transfer and friction losses were investigated and found to be greater than the losses from simple straight-tube PDEs. These losses are most pronounced (˜15%) when converging nozzles are used. The second portion of this work focuses on laser-based absorption sensing for PDEs. The mid-infrared was chosen as the best way to address the challenges of signal-to-noise ratio, sensitivity, robustness, and sensor bandwidth. A water vapor sensor was developed and applied to the PDE at the Naval Postgraduate School. This sensor provided improvements in temperature accuracy, and it revealed that water (generated by the vitiator) inhibited performance of the engine. Next, a JP-10 absorption sensor was developed and applied to the same engine. This sensor provided thermometry data at a higher temporal resolution than the water sensor. The sensor also provided crucial information on equivalence ratio and fuel arrival time which enabled the engine to be successfully operated on JP-10 and air for the first time.

Barbour, Ethan A.

403

Measuring Affect, Behavior and Cognition for Modeling Disaster Risk Attitudes.  

National Technical Information Service (NTIS)

The researchers modeled disaster risk attitudes using top down and bottom up approaches. Top down, they constructed an attitudinal model to comprise of affect, behavior and cognition (ABC). Bottom-up, they mined ABC semantics from narratives of disaster e...

H. M. Khalid M. G. Helander

2012-01-01

404

BioModel engineering for multiscale Systems Biology.  

PubMed

We discuss some motivational challenges arising from the need to model and analyse complex biological systems at multiple scales (spatial and temporal), and present a biomodel engineering framework to address some of these issues within the context of multiscale Systems Biology. Our methodology is based on a structured family of Petri net classes which enables the investigation of a given system using various modelling abstractions: qualitative, stochastic, continuous and hybrid, optionally in a spatial context. We illustrate our approach with case studies demonstrating hierarchical flattening, treatment of space, and hierarchical organisation of space. PMID:23067820

Heiner, Monika; Gilbert, David

2012-10-12

405

Modelling Gaia CCD pixels with Silvaco 3D engineering software  

NASA Astrophysics Data System (ADS)

Gaia will only achieve its unprecedented measurement accuracy requirements with detailed calibration and correction for radiation damage. We present our Silvaco 3D engineering software model of the Gaia CCD pixel and two of its applications for Gaia: (1) physically interpreting supplementary buried channel (SBC) capacity measurements (pocket-pumping and first pixel response) in terms of e2v manufacturing doping alignment tolerances; and (2) deriving electron densities within a charge packet as a function of the number of constituent electrons and 3D position within the charge packet as input to microscopic models being developed to simulate radiation damage.

Seabroke, G. M.; Prod'Homme, T.; Hopkinson, G.; Burt, D.; Robbins, M.; Holland, A.

2011-02-01

406

Model-Driven Engineering of Machine Executable Code  

NASA Astrophysics Data System (ADS)

Implementing static analyses of machine-level executable code is labor intensive and complex. We show how to leverage model-driven engineering to facilitate the design and implementation of programs doing static analyses. Further, we report on important lessons learned on the benefits and drawbacks while using the following technologies: using the Scala programming language as target of code generation, using XML-Schema to express a metamodel, and using XSLT to implement (a) transformations and (b) a lint like tool. Finally, we report on the use of Prolog for writing model transformations.

Eichberg, Michael; Monperrus, Martin; Kloppenburg, Sven; Mezini, Mira

407

A behavioral model of ethical and unethical decision making  

Microsoft Academic Search

A model is developed which identifies and describes various factors which affect ethical and unethical behavior in organizations, including a decision-maker's social, government and legal, work, professional and personal environments. The effect of individual decision maker attributes on the decision process is also discussed. The model links these influences with ethical and unethical behavior via the mediating structure of the

Michael Bommer; Clarence Gratto; Jerry Gravander; Mark Tuttle

1987-01-01

408

ADVANCED FAILURE MODES AND EFFECTS ANALYSIS USING BEHAVIOR MODELING  

Microsoft Academic Search

This paper presents a systematic method applicable at the early stages of design to enhance life-cycle quality of ownership: Advanced Failure Modes and Effect Analysis (AFMEA). The proposed method uses behavior modeling to simulate device operations and helps identify failure and customer dissatisfaction modes beyond component failures. The behavior model reasons about conditions that cause departures from normal operation and

Charles F. Eubanks; Steven Kmenta; Kosuke Ishii

1997-01-01

409

A transport model for prediction of wildfire behavior  

Microsoft Academic Search

Wildfires are a threat to human life and property, yet they are an unavoidable part of nature. In the past people have tried to predict wildfire behavior through the use of point functional models but have been unsuccessful at adequately predicting the gross behavior of the broad spectrum of fires that occur in nature. The majority of previous models do

R. R. Linn

1997-01-01

410

Creep-Rupture Behavior of Candidate Stirling Engine Iron Superalloys in High-Pressure Hydrogen. Volume II. Hydrogen Creep-Rupture Behavior.  

National Technical Information Service (NTIS)

The creep-rupture behavior of nine iron-base and one cobalt-base candidate Stirling engine alloys was evaluated at 650 to 925 exp 0 C in 15 MPa H sub 2 and air. The test alloys included six wrought alloys for tube application (CG-27, N-155, 19-9DL, 12 RN7...

S. Bhattacharyya W. Peterman C. Hales

1984-01-01

411

Model-Based Engineering and Manufacturing CAD/CAM Benchmark.  

SciTech Connect

The Benchmark Project was created from a desire to identify best practices and improve the overall efficiency and performance of the Y-12 Plant's systems and personnel supporting the manufacturing mission. The mission of the benchmark team was to search out industry leaders in manufacturing and evaluate their engineering practices and processes to determine direction and focus for Y-12 modernization efforts. The companies visited included several large established companies and a new, small, high-tech machining firm. As a result of this effort, changes are recommended that will enable Y-12 to become a more modern, responsive, cost-effective manufacturing facility capable of supporting the needs of the Nuclear Weapons Complex (NWC) into the 21st century. The benchmark team identified key areas of interest, both focused and general. The focus areas included Human Resources, Information Management, Manufacturing Software Tools, and Standards/Policies and Practices. Areas of general interest included Infrastructure, Computer Platforms and Networking, and Organizational Structure. The results of this benchmark showed that all companies are moving in the direction of model-based engineering and manufacturing. There was evidence that many companies are trying to grasp how to manage current and legacy data. In terms of engineering design software tools, the companies contacted were somewhere between 3-D solid modeling and surfaced wire-frame models. The manufacturing computer tools were varied, with most companies using more than one software product to generate machining data and none currently performing model-based manufacturing (MBM) from a common model. The majority of companies were closer to identifying or using a single computer-aided design (CAD) system than a single computer-aided manufacturing (CAM) system. The Internet was a technology that all companies were looking to either transport information more easily throughout the corporation or as a conduit for business, as the small firm was doing successfully.

Domm, T.C.; Underwood, R.S.

1999-10-13

412

Applying Model Based Systems Engineering (MBSE) to a standard CubeSat  

Microsoft Academic Search

Model Based Systems Engineering (MBSE) is an emerging technology that is providing the next advance in modeling and systems engineering. MBSE uses Systems Modeling Language (SysML) as its modeling language. SysML is a domain-specific modeling language for systems engineering used to specify, analyze, design, optimize, and verify systems. An MBSE Challenge project was established to model a hypothetical FireSat satellite

Sara C Spangelo; David Kaslow; Chris Delp; Bjorn Cole; Louise Anderson; Elyse Fosse; Brett Sam Gilbert; Leo Hartman; Theodore Kahn; James Cutler

2012-01-01

413

Modeling and cold start in alcohol-fueled engines  

SciTech Connect

Neat alcohol fuels offer several benefits over conventional gasoline in automotive applications. However, their low vapor pressure and high heat of vaporization make it difficult to produce a flammable vapor composition from a neat alcohol fuel during a start under cold ambient conditions. Various methods have been introduced to compensate for this deficiency. In this study, the authors applied computer modeling and simulation to evaluate the potential of four cold-start technologies for engines fueled by near-neat alcohol. The four technologies were a rich combustor device, a partial oxidation reactor, a catalytic reformer, and an enhanced ignition system. The authors ranked the competing technologies by their ability to meet two primary criteria for cold starting an engine at {minus}25 deg C and also by several secondary parameters related to commercialization. Their analysis results suggest that of the four technologies evaluated, the enhanced ignition system is the best option for further development.

Markel, A.J.; Bailey, B.K.

1998-05-01

414

Health behavior models and oral health: a review.  

PubMed

Dental hygienists help their clients develop health promoting behaviors, by providing essential information about general health, and oral health in particular. Individual health practices such as oral self-care are based on personal choices. The guiding principles found in health behavior models provide useful methods to the oral health care providers in promoting effective individual client behaviors. Theories provide explanations about observable facts in a systematic manner. Research regarding health behavior has explored the effectiveness and applicability of various health models in oral health behavior modification. The Health Belief Model, Transtheoretical Model and Stages of Change, Theory of Reasoned Action, Self-Efficacy, Locus of Control, and Sense of Coherence are examples of models that focus on individuals assuming responsibility for their own health. Understanding the strengths of each and their applicability to health behaviors is critical for oral health care providers who work with patients to adopt methods and modify behaviors that contribute to good oral health. This paper describes health behavior models that have been applied to oral health education, presents a critical analysis of the effectiveness of each model in oral health education, and provides examples of application to oral health education. PMID:16201062

Hollister, M Catherine; Anema, Marion G

2004-01-01

415

Engineering/economic end-use energy models  

SciTech Connect

The objective of this paper is to provide a glimpse of the current technology of engineering/economic end-use energy models. In providing this glimpse, it was found desirable to articulate three subsidiary objectives. The first objective describes end-use modeling within the broader context of an analytical framework capable of producing statistically sound and valid forecasts. The second objective highlights those aspects of the end-use modeling problem that are associated with technology and technology characterization. The third objective describes results of a policy application. The authors hope that the latter two objectives provide insights to the physics community concerning how and how well their inputs to the end-use modeling problem are employed. 19 references, 3 figures, 2 tables.

Hamblin, D.M.; Vineyard, T.A.

1985-01-01

416

Modeling robustness behavior using aspect-oriented modeling to support robustness testing of industrial systems  

Microsoft Academic Search

Model-based robustness testing requires precise and complete behavioral, robustness modeling. For example, state machines\\u000a can be used to model software behavior when hardware (e.g., sensors) breaks down and be fed to a tool to automate test case\\u000a generation. But robustness behavior is a crosscutting behavior and, if modeled directly, often results in large, complex state\\u000a machines. These in practice tend

Shaukat Ali; Lionel C. Briand; Hadi Hemmati

417

Emerging Conceptual Models of Excessive Behaviors  

Microsoft Academic Search

The clinical assessment of a common behavior that disrupts a person’s life only when it becomes excessive is controversial.\\u000a The inclusion of pathological gambling in the Diagnostic and Statistical Manual, Third Edition (DSM-III) in 1980 was one of\\u000a the initial formal attempts to develop diagnostic criteria for this type of behavior. The diagnostic criteria for pathological\\u000a gambling were based on

James Westphal

2007-01-01

418

The role of behavior in translational models for psychopathology: Functionality and dysfunctional behaviors.  

PubMed

The history of science has frequently included a problem-based impetus toward research that can be translated expeditiously into solutions. A current problem is that psychopathologies, typically chronic, contribute hugely to the economic and social burden of medical care, especially in the United States. For behavioral neuroscientists a psychopathology-aimed translational research emphasis particularly involves animal models to facilitate the experimental and invasive work necessary to an understanding of the biology of normal and aberrant behavior. When the etiology of a particular psychopathology is unknown, and there are no specific biomarkers, behavioral parallels between the focal disorder and its putative models become crucial elements in assessing model validity. Evaluation of these parallels is frequently neglected, reflecting in part the lack of a systematic conceptualization of the organization of behavior and how this may be conserved across species. Recent work specifically attempting to bridge this gap suggests that analysis of behaviors that are functional - adaptive in crucial situations such as danger or social contexts - can facilitate an understanding of the parallels between behaviors of human and nonhuman species, including the dysfunctional behaviors of psycho pathologies. As research with animal models comes to provide a more systematic analysis of particular behaviors and their adaptive functions, cross-talk between model and focal psychopathology may be advantageous to understanding both. PMID:23791787

Blanchard, D Caroline; Summers, Cliff H; Blanchard, Robert J

2013-06-18

419

Calibrating Bayesian Network Representations of Social-Behavioral Models  

SciTech Connect

While human behavior has long been studied, recent and ongoing advances in computational modeling present opportunities for recasting research outcomes in human behavior. In this paper we describe how Bayesian networks can represent outcomes of human behavior research. We demonstrate a Bayesian network that represents political radicalization research – and show a corresponding visual representation of aspects of this research outcome. Since Bayesian networks can be quantitatively compared with external observations, the representation can also be used for empirical assessments of the research which the network summarizes. For a political radicalization model based on published research, we show this empirical comparison with data taken from the Minorities at Risk Organizational Behaviors database.

Whitney, Paul D.; Walsh, Stephen J.

2010-04-08

420

NASA Marshall Engineering Thermosphere Model--Version 2.0  

NASA Astrophysics Data System (ADS)

This paper will describe the new NASA Marshall Engineering Thermosphere Model- Version 2.0 (MET-V 2.0) along with an explanation on the use of the computer program plus an example of the MET-V 2.0 model products. The MET-V 2.0 provides an update to the 1988 version of the model. This model provides information on the total mass density, temperature, and individual species number densities for any altitude between 90 and 2500 km as a function of latitude, longitude, time, and solar and geomagnetic activity. A description is given for use of estimated future 13-month smoothed solar flux and geomagnetic index values as input to the model. Using current or past observations of solar radio flux and geomagnetic activity as inputs to the MET-V2.0 model will produce thermospheric density estimates with an accuracy of about 15 percent. However, using future estimates of these input values from generally accepted statistical models (no physical solar model is available for use currently) will result in significantly (order of magnitude effects) reduced accuracy for the calculated thermospheric density values. These are key considerations to the prediction and statistical confidence of satellite orbital lifetimes, orbital insertion altitudes, re-boost requirement, etc for which the MET- V2.0 model (and its predecessors) was developed.

Owens, J.; Vaughan, W.

421

Deformation Behavior of Fiber-Reinforced Polymer Reinforced Engineered Cementitious Composite (ECC) Flexural Members under Reversed Cyclic Loading Conditions  

Microsoft Academic Search

This study investigates the response of fiber-reinfor ced polymer (FRP) reinforced engineered cementitious composite (ECC) members with a focus on their flexural load-deformation behavior, residual deflection, damage evolution, and failure mode. Critical aspects of conventional FRP-reinforced concrete members—such as interfacial bond strength, flexural crack formation, composite deformation behavior, and brittle failure mode—are briefly reviewed and compared to FRP reinforced ECC.

Gregor Fischer; Victor C. Li

422

Methods for model selection in applied science and engineering.  

SciTech Connect

Mathematical models are developed and used to study the properties of complex systems and/or modify these systems to satisfy some performance requirements in just about every area of applied science and engineering. A particular reason for developing a model, e.g., performance assessment or design, is referred to as the model use. Our objective is the development of a methodology for selecting a model that is sufficiently accurate for an intended use. Information on the system being modeled is, in general, incomplete, so that there may be two or more models consistent with the available information. The collection of these models is called the class of candidate models. Methods are developed for selecting the optimal member from a class of candidate models for the system. The optimal model depends on the available information, the selected class of candidate models, and the model use. Classical methods for model selection, including the method of maximum likelihood and Bayesian methods, as well as a method employing a decision-theoretic approach, are formulated to select the optimal model for numerous applications. There is no requirement that the candidate models be random. Classical methods for model selection ignore model use and require data to be available. Examples are used to show that these methods can be unreliable when data is limited. The decision-theoretic approach to model selection does not have these limitations, and model use is included through an appropriate utility function. This is especially important when modeling high risk systems, where the consequences of using an inappropriate model for the system can be disastrous. The decision-theoretic method for model selection is developed and applied for a series of complex and diverse applications. These include the selection of the: (1) optimal order of the polynomial chaos approximation for non-Gaussian random variables and stationary stochastic processes, (2) optimal pressure load model to be applied to a spacecraft during atmospheric re-entry, and (3) optimal design of a distributed sensor network for the purpose of vehicle tracking and identification.

Field, Richard V., Jr.

2004-10-01

423

Performance and NO\\/sub x\\/ emissions modeling of a jet ignition prechamber stratified charge engine  

Microsoft Academic Search

The development of a cycle simulation model for the jet ignition prechamber stratified charge engine is described. Given the engine geometry, load, speed, air-fuel ratios and pressures and temperatures in the two intakes, flow ratio and a suitable combustion model, the cycle simulation predicts engine indicated efficiency and NO emissions. The relative importance of the parameters required to define the

S. D. Hires; A. Ekchian; J. B. Heywood; R. J. Tabaczynaki; J. C. Wall

1976-01-01

424

A probabilistic model for validation of behavioral hierarchies  

Microsoft Academic Search

A probabilistic model for the validation of behavioral hierarchies is presented. Estimation is by means of iterative convergence to maximum likelihood estimates, and two approaches to assessing the fit of the model to sample data are discussed. The relation of this general probabilistic model to other more restricted models which have been presented previously is explored and three cases of

C. Mitchell Dayton; George B. Macready

1976-01-01

425

Behavior-Based Credit Card Fraud Detecting Model  

Microsoft Academic Search

Credit card frauds,which always cause great loss for credit card holder, is also a big problem for financial banks. A credit card fraud detecting model is established based on the behavior patterns of the credit card holder.Different with traditional models which were based on demographic and economic information,this model detects credit card fraud with historical behavior patterns of the credit

Yongbin Zhang; Fucheng You; Huaqun Liu

2009-01-01

426

Theory development for HIV behavioral health: empirical validation of behavior health models specific to HIV risk  

Microsoft Academic Search

In the presence of numerous health behavior theories, it is difficult to determine which of the many theories is most precise in explaining health-related behavior. New models continue to be introduced to the field, despite already existing disparity, overlap, and lack of unification among health promotion theories. This paper will provide an overview of current arguments and frameworks for testing

Dorian E. Traube; Ian W. Holloway; Lana Smith

2011-01-01

427

A stressor-strain model of organizational citizenship behavior and counterproductive work behavior  

Microsoft Academic Search

Prior research has attempted to develop a model of organizational citizenship behaviors (OCB) and counterproductive work behaviors (CWB), but limited testing remains a problem. The purpose of the current study is to examine OCB and CWB from a job stressor-strain approach. The sample consisted of 235 employees throughout the United States and their supervisors. Results of the study suggested OCB

Kimberly E OBrien

2008-01-01

428

Optimization of Combustion Chamber for Diesel Engine Using Kriging Model  

NASA Astrophysics Data System (ADS)

Diesel engine combustion chamber which reduces exhaust emission has been designed using CFD analysis and optimization techniques. In order to save computational time for design, the Kriging model, one of the response surface models, is adopted here. For a robust exploration, both the estimated function value of the model and its uncertainty are considered at the same time. In the present problem, the k-means method is used to limit the number of additional sample points to a reasonable level. Among the additional sample points, two combustion chamber shapes dominate the baseline configuration in terms of all objective functions. Compared with the previous optimization with the evolutionary algorithm, its computational time for design was cut by 95%. The results indicate that the present method is a practical approach for real-world applications.

Jeong, Shinkyu; Minemura, Youichi; Obayashi, Shigeru

429

Experiences in Model Driven Verification of Behavior with UML  

NASA Astrophysics Data System (ADS)

Model Driven Development (MDD) focuses on the intensive use of models during software development. In this paradigm, models are the central development artifact: transformations are used to derive executable programs, or tests for a given platform. This makes building quality models a cost-effective approach, as the models can be reused for many analysis or generation goals, and not just document a design. However, high quality models are needed for the approach to be successful. Hence the goal of performing analysis of high-level behavioral specifications such as UML, to enhance their quality and detect defects or ensure desired behavior.

Kordon, Fabrice; Thierry-Mieg, Yann

430

Loss terms in free-piston Stirling-engine models. Final Technical Report  

SciTech Connect

Various models for free piston Stirling engines are reviewed. Initial models were developed primarily for design purposes and to predict operating parameters, especially efficiency. More recently, however, such models have been used to predict engine stability. Free piston Stirling engines have no kinematic constraints and stability may not only be sensitive to the load, but also to various nonlinear loss and spring constraints. The present understanding is reviewed of various loss mechanisms for free piston Stirling engines and how they have been incorporated into engine models is discussed.

Gordon, L.B.

1992-01-01

431

Models to examine containment and spread of genetically engineered microbes  

Microsoft Academic Search

Genetically engineered microbes (GEMs) have the potential to\\u000a revolutionize agricultural techniques by facilitating crop protection\\u000a and increased productivity. However, there has been widespread concern\\u000a regarding the potential impact these microbes may have on the\\u000a environment. Here we mathematically model the dynamics of GEMs in an\\u000a agricultural setting, focusing on parameters that can be used to\\u000a summarize the potential of modified

M. A. LEWIS; G. SCHMITZ; P. KAREIVA; J. T. TREVORS

1996-01-01

432

Mathematical Models and the Experimental Analysis of Behavior  

PubMed Central

The use of mathematical models in the experimental analysis of behavior has increased over the years, and they offer several advantages. Mathematical models require theorists to be precise and unambiguous, often allowing comparisons of competing theories that sound similar when stated in words. Sometimes different mathematical models may make equally accurate predictions for a large body of data. In such cases, it is important to find and investigate situations for which the competing models make different predictions because, unless two models are actually mathematically equivalent, they are based on different assumptions about the psychological processes that underlie an observed behavior. Mathematical models developed in basic behavioral research have been used to predict and control behavior in applied settings, and they have guided research in other areas of psychology. A good mathematical model can provide a common framework for understanding what might otherwise appear to be diverse and unrelated behavioral phenomena. Because psychologists vary in their quantitative skills and in their tolerance for mathematical equations, it is important for those who develop mathematical models of behavior to find ways (such as verbal analogies, pictorial representations, or concrete examples) to communicate the key premises of their models to nonspecialists.

Mazur, James E

2006-01-01

433

Observation of Flow Characteristics in a Model I.C. Engine Cylinder.  

National Technical Information Service (NTIS)

A study of fluid mechanical effects on unburned hydrocarbon generation was made in a single compression expansion model automobile engine. Full optical access allowed the color Schlieren observations of various gas motion alongside the engine cylinder. Mo...

N. Ishikawa J. W. Daily

1978-01-01

434

Air Force Systems Engineering Assessment Model (AF SEAM) Management Guide, Version 2.  

National Technical Information Service (NTIS)

The primary purpose of the Air Force Systems Engineering Assessment Model (AF SEAM) is to promote the application and use of standard Systems Engineering (SE) processes across the AF and to improve the performance of these processes through Continuous Pro...

2010-01-01

435

Multi-modeling of adversary behaviors  

Microsoft Academic Search

Models developed using different modeling languages but the same data provide different insights of the human terrain. Interoperation of such models, i.e., multi-modeling, can produce a more robust modeling and simulation capability to support operational commanders or intelligence analysts. The C2 Wind Tunnel is a platform that enables multi-modeling and the conduct of simulations and computational experiments. However, to establish

Alexander H. Levis; Lee W. Wagenhals; Abbas K. Zaidi

2010-01-01

436

The LAILAPS search engine: a feature model for relevance ranking in life science databases.  

PubMed

Efficient and effective information retrieval in life sciences is one of the most pressing challenge in bioinformatics. The incredible growth of life science databases to a vast network of interconnected information systems is to the same extent a big challenge and a great chance for life science research. The knowledge found in the Web, in particular in life-science databases, are a valuable major resource. In order to bring it to the scientist desktop, it is essential to have well performing search engines. Thereby, not the response time nor the number of results is important. The most crucial factor for millions of query results is the relevance ranking. In this paper, we present a feature model for relevance ranking in life science databases and its implementation in the LAILAPS search engine. Motivated by the observation of user behavior during their inspection of search engine result, we condensed a set of 9 relevance discriminating features. These features are intuitively used by scientists, who briefly screen database entries for potential relevance. The features are both sufficient to estimate the potential relevance, and efficiently quantifiable. The derivation of a relevance prediction function that computes the relevance from this features constitutes a regression problem. To solve this problem, we used artificial neural networks that have been trained with a reference set of relevant database entries for 19 protein queries. Supporting a flexible text index and a simple data import format, this concepts are implemented in the LAILAPS search engine. It can easily be used both as search engine for comprehensive integrated life science databases and for small in-house project databases. LAILAPS is publicly available for SWISSPROT data at http://lailaps.ipk-gatersleben.de. PMID:20375444

Lange, Matthias; Spies, Karl; Colmsee, Christian; Flemming, Steffen; Klapperstück, Matthias; Scholz, Uwe

2010-03-25

437

Children's Use of the Yahooligans! Web Search Engine. III. Cognitive and Physical Behaviors on Fully Self-Generated Search Tasks.  

ERIC Educational Resources Information Center

|Presents the third part of a research project that investigated information-seeking behavior and success of seventh-grade science children in using the Yahooligans! Web search engine/directory. Children were more successful on a fully self-generated task than one two fully assigned tasks and were more successful when they browsed than when they…

Bilal, Dania

2002-01-01

438

Atmospheric Photochemical Modeling of Turbine Engine Fuels and Exhaust. Phase 2. Computer Model Development, Volume 1 of 2.  

National Technical Information Service (NTIS)

A computer model capable of predicting photochemical reactivity of turbine engine fuel emissions and exhaust emissions from routine AF operations is developed. This Phase II report describes experimental work on engine exhaust components conducted in envi...

A. M. Winer M. P. Poe R. Atkinson S. E. Heffron W. O. Carter

1988-01-01

439

Three dimensional modelling of combustion in a prechamber diesel engine  

SciTech Connect

Three dimensional modelling appears to be a good way to analyze the influence of the major parameters involved in the diesel combustion process. The computer code KIVA was modified and improved in order to be applicable to very complex combustion chamber shapes. A new mesh generator was used and coupled to KIVA. Modelling the diesel combustion required the implementation of new sub-models in the code. A{kappa}-{epsilon} turbulence model was used. Heat transfer rates to the wall were computed using a model based on a {kappa}-{epsilon} formulation. Combustion was to be controlled by species and heat diffusion only. This assumption allowed the use of the Magnussen Eddy Break Up combustion model. The complete model was applied to the simulation of flow and combustion in a Ricardo COMET prechamber diesel engine. The authors studied the fluid dynamics and the evolution of combustion in both the pre- and main combustion chambers. The influence of the position of the glow plug and of the piston shape were investigated. The studies of the flow show that addition of the glow plug in the prechamber reduces the swirl level to less than half its level without the plug. Comparisons between computational results and experimental flame visualizations performed elsewhere reveal a good qualitative agreement. The computed global heat release rate is found to follow the experimental trends.

Pinchon, P.

1989-01-01

440

Developing model-eliciting activities for undergraduate students based on advanced engineering content  

Microsoft Academic Search

Are you interested in creating open-ended, client-driven, realistic engineering tasks for undergraduate students that will introduce them to the world of engineering early in their academic careers? With the support of the National Science Foundation, model-eliciting activities (MEAs) were created and implemented with first-year engineering students at Purdue University. These tasks are open-ended modeling problems that introduce advanced engineering content

Tamara Moore; Heidi Diefes-Dux

2004-01-01

441

An instrumental variable approach to non-linear model-based adaptive control of engine speed  

Microsoft Academic Search

An instrumental variable approach to non-linear model-based adaptive control of engine speed regulation was investigated and implemented on a spark ignition internal combustion engine. A four-step version of instrumental variable parameter estimation is used to identify a bias-free and noise tolerant model of the engine dynamics from the by-pass air valve voltage input to the output engine speed. The parametric

Jonathan W. Anders; Matthew A. Franchek

2005-01-01

442

Modeling Geographic Behavior in Riotous Crowds  

Microsoft Academic Search

Under some conditions, tensions among crowd members, harbored a priori or developed on site, might catalyze a crowd to riot, with dramatic consequences. We know perhaps less than we would like to about the processes that drive rioting in crowds because they are difficult to study. In particular, we know relatively little about the influence of geographic behavior on rioting,

Paul M. Torrens; Aaron W. McDaniel

2012-01-01

443

Modeling Browsing Behavior at Multiple Websites  

Microsoft Academic Search

While there is a growing literature on investigating the Internet clickstream data collected for a single site, such datasets are inherently incomplete because they generally do not capture shopping behavior across multiple websites. A customer's visit patterns at one or more other sites may provide relevant information about the timing and frequency of his or her future visit patterns at

Young-Hoon Park; Peter S. Fader

2004-01-01

444

Health Educators: Role Modeling and Smoking Behavior.  

ERIC Educational Resources Information Center

|Examined cigarette smoking among health educators, their views about the effects of this behavior upon their audiences and beliefs about smoking in light of their professional role. Smokers and nonsmokers were significantly less included than former smokers to feel the role of health education is to convince people not to smoke. (Author/ABL)|

Brennan, Andrew J. J.; Galli, Nicholas

1985-01-01

445

Modeling Ant Behavior Under a Variable Environment  

Microsoft Academic Search

This paper studies the behavior of ants when moving in an artificial network composed of several interconnected paths linking their nest to a food source. The ant responses when temporarily blocking the access to some branches of the maze were observed in order to study which factors influenced their local decisions about the paths to follow. We present a mathematical

Karla Vittori; Jacques Gautrais; Aluizio F. R. Araújo; Vincent Fourcassié; Guy Theraulaz

2004-01-01

446

Steel Shear Walls, Behavior, Modeling and Design  

Microsoft Academic Search

In recent years steel shear walls have become one of the more efficient lateral load resisting systems in tall buildings. The basic steel shear wall system consists of a steel plate welded to boundary steel columns and boundary steel beams. In some cases the boundary columns have been concrete-filled steel tubes. Seismic behavior of steel shear wall systems during actual

Abolhassan Astaneh-Asl; Abolhassan

2008-01-01

447

A comparison of two combustor modeling approaches for real time turbofan engine model  

Microsoft Academic Search

This paper presents two combustor modeling approaches for real time turbofan engine model. The two approaches are called Integral Approach and Hybrid Approach. Integral Approach resorts to the effect of mass and energy storage in a volume to establish the pressure and temperature differential equations. Whereas Hybrid Approach considers only the effect of mass storage in a volume to achieve

Kong Xiangxing; Wang Xi

2010-01-01

448

A Multidisciplinary Model for Using Robotics in Engineering Education  

Microsoft Academic Search

The use of robotics to provide hands-on instruction across the various disciplines of engineering and computer science is no longer the prohibitively expensive proposition it once was. With the emergence of inexpensive robot kits that encompass a background in electrical engineering, mechanical engineering, industrial engineering, and computer science, robotics can now play a central role in the education of students

Jerry B. Weinberg; George L. Engel; Keqin Gu; Cem S. Karacal; Scott R. Smith; William W. White; Xudong W. Yu

2001-01-01

449

Generic Engineering Competencies: A Review and Modelling Approach  

ERIC Educational Resources Information Center

|This paper puts forward the view that engineering educators have a responsibility to prepare graduates for engineering work and careers. The current literature reveals gaps between the competencies required for engineering work and those developed in engineering education. Generic competencies feature in these competency gaps. Literature suggests…

Male, Sally A.

2010-01-01

450

A Model for Transferable Integrated Design Engineering Education  

Microsoft Academic Search

Historically, the teaching of engineering design has varied widely, depending heavily on the design instructor. In many cases, educational outcomes cited for engineering design have focused on quality of design products and neglected the professional skills necessary for design. Recent pressures from employers of engineering graduates and accrediting agencies for engineering programs are directing increased attention to design and professional

Denny Davis; Michael Trevisan; Kenneth Gentili; David McLean

2003-01-01

451

A Cylindrical Model of Communication Behavior in Crisis Negotiations.  

ERIC Educational Resources Information Center

|Integrates existing theoretical perspectives on message content and negotiator motivation to formulate a comprehensive definitional model of the interrelationships among communication behaviors in crisis negotiation. Finds that the intensity of communication plays a polarizing role in the cylinder, with intense, functionally discrete behaviors

Taylor, Paul J.

2002-01-01

452

Aggressive Male APP23 Mice Modeling Behavioral Alterations in Dementia  

Microsoft Academic Search

In addition to cognitive deterioration, Alzheimer's disease patients exhibit behavioral and psychological signs and symptoms of dementia. Behavioral alterations are a major source of caregiver stress and an important contributor in the decision to institutionalize patients. The amyloid precursor protein (APP) 23 transgenic mouse model develops amyloid plaques from the age of 6 months onward and exhibits tau pathology, which

Ellen Vloeberghs; Debby Van Dam; Katrien Coen; Matthias Staufenbiel; Peter Paul De Deyn

2006-01-01

453

Modeling the Antecedents of Proactive Behavior at Work  

Microsoft Academic Search

Using a sample of U.K. wire makers (N = 282), the authors tested a model in which personality and work environment antecedents affect proactive work behavior via cognitive-motivational mechanisms. Self-reported proactive work behaviors (proactive idea implementation and proactive problem solving) were validated against rater assessments for a subsample (n = 60) of wire makers. With the exception of supportive supervision,

Sharon K. Parker; Helen M. Williams; Nick Turner

2006-01-01

454

Modeling and exploiting behavior patterns in dynamic environments  

Microsoft Academic Search

This paper presents a new approach to improving the effectiveness of autonomous systems that deal with dynamic environments. The basis of the approach is to find repeating patterns of behavior in the dynamic elements of the system, and then to use predictions of the repeating elements to better plan goal directed behavior. It is a layered approach involving classifying, modeling,

David Ball; Gordon Wyeth

2004-01-01

455

Do role models influence teenagers’ purchase intentions and behavior?  

Microsoft Academic Search

Attempts to determine which individual, or group of individuals, has the strongest influence on adolescent consumer purchase intentions and purchase behavior. By introducing the concepts of direct (fathers and mothers) and vicarious (favorite entertainers and favorite athletes) role models into the consumer behavior literature, the study allows greater understanding of the socialization patterns of young adult consumers. Results from this

Craig A. Martin; Alan J. Bush

2000-01-01

456

A STUDY OF B2C CONSUMER BEHAVIOR MODEL  

Microsoft Academic Search

The purpose of this research is to verify a preliminary B2C consumer behavior model that is constructed previously by brainstorming, structured interview, and on-line observation. Twelve subjects voluntarily participated in the verification experiment. Thinking aloud method was used for the experiment. Subjects were asked to do online shopping in an experimental environment and their behavioral processes were recorded by video

Min-yang Wang; Hui-Ming Kuo; Sheue-Ling Hwang

2005-01-01

457

An Examination of a Model of Anti-Pollution Behavior.  

ERIC Educational Resources Information Center

|Reports results of a study in which Japanese female undergraduates (N=118) responded to an environmental concern scale based upon a model of anti-pollution behavior focusing on: approach to information, confidence in science and technology, appreciation of natural beauty, causes, consequences, and purchasing and coping behaviors. (DC)|

Iwata, Osamu

1981-01-01

458

76 FR 42609 - Airworthiness Directives; Lycoming Engines Model TIO 540-A Series Reciprocating Engines  

Federal Register 2010, 2011, 2012, 2013

...another AD, before we rescind the engine-level AD. DATES: We must...Certification Office, FAA, Engine & Propeller Directorate, 1600...proposed AD rescission. Using the search function of the Web site, anyone...Discussion In June of 1971, the FAA Engine & Propeller Directorate...

2011-07-19

459

Engineering Infrastructure Diagramming and Modeling. Engineering Education and Practice in The United States.  

ERIC Educational Resources Information Center

This report forms an integral part of a study conducted by the Committee on the Education and Utilization of the Engineer, under the auspices of the National Research Council. Five major tasks undertaken by the panel were: (1) defining engineering; (2) determining influences on the engineering community, including external influences and internal…

National Academy of Sciences - National Research Council, Washington, DC. Commission on Engineering and Technical Systems.

460

Modeling and identification of an electromechanical internal combustion engine throttle body  

Microsoft Academic Search

Efficient control of the electromechanical throttle body of internal combustion engines allows one to properly regulate the additional air flow provided to the engine in idle speed conditions. The behavior of the throttle is highly nonlinear, due to its mechanical characteristics and to significant friction forces. The systematic design of the control strategy calls for the availability of a reliable

R. Scattolini; C. Siviero; M. Mazzucco; S. Ricci; L. Poggio; C. Rossi

1997-01-01

461

Enforcing social behavior in an Ising model with complex neighborhoods  

NASA Astrophysics Data System (ADS)

We consider the problem of enforcing desired behavior in a population of individuals modeled by an Ising model. Although there is a large literature dealing with social interaction models, the problem of controlling behavior in a system modeled by the Ising model seems to be an unexplored field. First, we provide and analytically characterize an optimal policy that may be used to achieve this objective. Second, we show that complex neighborhoods highly influence the decision making process. Third, we use Lagrange multipliers associated to some constraints of a related problem to identify the role of individuals in the system.

Cajueiro, D. O.

2011-05-01

462

Systems engineering design and spatial modeling for improved natural hazard risk assessment  

Microsoft Academic Search

Purpose – The purpose of this paper is to present a novel modeling approach that combines a balanced systems engineering design model with a geospatial model to explore the complex interactions between natural hazards and engineered systems. Design\\/methodology\\/approach – The approach taken in this work was to assemble a combined systems engineering design\\/geospatial model and interface it with a physics-based

T. J. Eveleigh; T. A. Mazzuchi; S. Sarkani

2006-01-01

463

Behavior modeling through CHAOS for simulation of dismounted soldier operations  

NASA Astrophysics Data System (ADS)

One of the major challenges in human behavior modeling for military applications is dealing with all factors that can influence behavior and performance. In a military context, behavior and performance are influenced by the task at hand, the internal (cognitive and physiological) and external (climate, terrain, threat, equipment, etc.) state. Modeling the behavioral effects of all these factors in a centralized manner would lead to a complex rule-base that is difficult to maintain or expand. To better cope with this complexity we have developed the Capability-based Human-performance Architecture for Operational Simulation (CHAOS). CHAOS is a multi-agent system for human behavior modeling that is based on pandemonium theory. Every agent in CHAOS represents a specific part of behavior, such as 'reaction to threat' or 'performing a patrol task'. These agents are competing over a limited set of resources that represent human capabilities. By combining the element of competition with multiple limited resources, CHAOS allows us to model stress, strain and multi-tasking in an intuitive manner. The CHAOS architecture is currently used in firefighter and dismounted soldier simulations and has shown itself to be suitable for human behavior and performance modeling.

Ubink, Emiel; Aldershoff, Frank; Lotens, Wouter; Woering, Arend

2008-05-01

464

3D Model Generation From the Engineering Drawing  

NASA Astrophysics Data System (ADS)

The contribution deals with the transformation of engineering drawings in a paper form into a 3D computer representation. A 3D computer model can be further processed in CAD/CAM system, it can be modified, archived, and a technical drawing can be then generated from it as well. The transformation process from paper form to the data one is a complex and difficult one, particularly owing to the different types of drawings, forms of displayed objects and encountered errors and deviations from technical standards. The algorithm for 3D model generating from an orthogonal vector input representing a simplified technical drawing of the rotational part is described in this contribution. The algorithm was experimentally implemented as ObjectARX application in the AutoCAD system and the test sample as the representation of the rotational part was used for verificaton.

Vaský, Jozef; Eliáš, Michal; Bezák, Pavol; ?erve?anská, Zuzana; Izakovi?, Ladislav

2010-01-01

465

Behavior Change Support Systems: A Research Model and Agenda  

NASA Astrophysics Data System (ADS)

This article introduces the concept of a behavior change support system and suggests it as a key construct for research on persuasive systems design, technologies, and applications. Key concepts for behavior change support systems are defined and a research agenda for them is outlined. The article suggests that a change in complying, a behavior change, and an attitude change (C-, B- or A-Change) constitute the archetypes of a behavioral change. Change in itself is either of a forming, altering or reinforcing outcome (F-, A- or R-Outcome). This research model will become helpful in researching and designing persuasive technology.

Oinas-Kukkonen, Harri

466

Pilot Behavior Models for LSO (Landing Signal Officer) Training Systems.  

National Technical Information Service (NTIS)

This report promulgates results of a project to develop pilot/aircraft behavior models for an automated LSO training system. Data supporting the identification of critical LSO task conditions were collected through literature search, accident report revie...

J. T. Hooks W. S. McMurry

1983-01-01

467

Developing 'integrative' zebrafish models of behavioral and metabolic disorders.  

PubMed

Recently, the pathophysiological overlap between metabolic and mental disorders has received increased recognition. Zebrafish (Danio rerio) are rapidly becoming a popular model organism for translational biomedical research due to their genetic tractability, low cost, quick reproductive cycle, and ease of behavioral, pharmacological or genetic manipulation. High homology to mammalian physiology and the availability of well-developed assays also make the zebrafish an attractive organism for studying human disorders. Zebrafish neurobehavioral and endocrine phenotypes show promise for the use of zebrafish in studies of stress, obesity and related behavioral and metabolic disorders. Here, we discuss the parallels between zebrafish and other model species in stress and obesity physiology, as well as outline the available zebrafish models of weight gain, metabolic deficits, feeding, stress, anxiety and related behavioral disorders. Overall, zebrafish demonstrate a strong potential for modeling human behavioral and metabolic disorders, and their comorbidity. PMID:23948218

Nguyen, Michael; Yang, Ester; Neelkantan, Nikhil; Mikhaylova, Alina; Arnold, Raymond; Poudel, Manoj K; Stewart, Adam Michael; Kalueff, Allan V

2013-08-12

468

A catastrophe-theory model for simulating behavioral accidents  

SciTech Connect

Behavioral accidents are a particular type of accident. They are caused by inappropriate individual behaviors and faulty reactions. Catastrophe theory is a means for mathematically modeling the dynamic processes that underlie behavioral accidents. Based on a comprehensive data base of mining accidents, a computerized catastrophe model has been developed by the Bureau of Mines. This model systematically links individual psychological, group behavioral, and mine environmental variables with other accident causing factors. It answers several longstanding questions about why some normally safe behaving persons may spontaneously engage in unsafe acts that have high risks of serious injury. Field tests with the model indicate that it has three imnportant uses: it can be used as a effective training aid for increasing employee safety consciousness; it can be used as a management laboratory for testing decision alternatives and policies; and it can be used to help design the most effective work teams.

Souder, W.E.

1988-01-01

469

Lumped parameter modeling of the actuator behavior of ferrogels  

NASA Astrophysics Data System (ADS)

Ferrogels are compliant composite materials formed of a soft polymer matrix with a filler of magnetic powder. The interaction of the magnetic filler with an applied magnetic field causes the deformation of the ferrogel. Strains of up to 40% have been measured with load capabilities of up to four times the sample's weight. As these materials move toward application it is important to capture the actuator behavior in mathematical models so that materials can be designed and the behavior predicted. In this work experimental testing captures the strain and strain rate behavior of these materials at fields up to 0.5 T. A lumped parameter model is then developed that is much less computationally intensive than existing modeling approaches. The ability of this model to capture the behavior of interest will be assessed.

Faidley, Leann E.; McLaurin, Elease J.

2009-03-01

470

Some considerations for modeling the creep behavior of composite materials  

SciTech Connect

A simple treatment of the mechanics of creep in unidirectional composites is presented with the objective of stressing the need for using appropriate constitutive equations when modeling the behavior of the constituents. It is demonstrated that pseudo-constitutive relations, such as those obtained from constant stress creep experiments for example, can not be used to describe the mechanical behavior of the constituents when modeling the creep of composites. By describing the mechanical behavior of the composite constituents using linear viscoelastic models, an analysis is presented to assess the type of errors which are incurred when inappropriate constitutive relations are used. Other considerations for modeling the creep behavior of ceramic matrix composites are discussed.

Lara-Curzio, E.; Ferber, M.K.

1994-05-01

471

A Behavior Change Model for Internet Interventions  

Microsoft Academic Search

Background  The Internet has become a major component to health care and has important implications for the future of the health care\\u000a system. One of the most notable aspects of the Web is its ability to provide efficient, interactive, and tailored content\\u000a to the user. Given the wide reach and extensive capabilities of the Internet, researchers in behavioral medicine have been

Lee M. Ritterband; Frances P. Thorndike; Daniel J. Cox; Boris P. Kovatchev; Linda A. Gonder-Frederick

2009-01-01

472

Understanding and Modeling Freight Stakeholder Behavior.  

National Technical Information Service (NTIS)

The project developed a conceptual model of private-sector freight stakeholder decisions and interactions for forecasting freight demands in response to key policy variables. Using East Central Wisconsin as a study area, empirical models were developed fo...

J. Y. Guo Q. Gong

2012-01-01

473

Thermohydrologic Modeling: Coupling Navier-Stokes Models of Gas, Moisture, and Heat Flow in Underground Engineered Systems with Porous-Media Models in Fractured Rocks  

NASA Astrophysics Data System (ADS)

Combined free and porous flows occur in a wide range of natural and engineered systems such as coupled transport processes driven by underground-engineered systems. One potential application for modeling these coupled flow processes is related to the emplacement of heat-generating radioactive waste package in tunnels lying above the water table. This example involves the flow of gas and moisture in large open tunnel and gas- and liquid-phase flow in the surrounding fractured, porous rocks. This study aims to develop a method of coupling the Navier-Stokes equations and the Darcy's law to achieve a more rigorous representation of all major flow and transport processes in underground tunnels and surrounding fractured host-rocks. While the thermohydrologic (TH) processes in host-rocks are treated based on porous-medium Darcy-flow approximations, the Navier-Stokes modeling is applied to describe in-tunnel flow behaviors (natural convection, realistic gas/moisture movement, turbulent flow conditions, etc.). The governing equations are numerically solved by a finite-element scheme in the NUFT code. Some numerical simulation results shown in this presentation provide environmental conditions that engineered systems would experience, which, therefore, may be useful for engineered system design analysis and performance assessment. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Hao, Y.; Nitao, J. J.; Buscheck, T. A.; Sun, Y.; Lee, K. H.

2004-12-01

474

Model, Need, and Cost Effects in Helping Behavior.  

National Technical Information Service (NTIS)

The study was designed (a) to assess the effects of a selfish model on helping behavior in comparison to the effects of a generous model, (b) to identify situational factors which might be differentially conducive to model effects, and (c) to develop hypo...

C. M. Wagner L. Wheeler

1968-01-01

475

Asynchronous Control Device Design by Net Model Behavior Simulation  

Microsoft Academic Search

We discuss the problem of designing asynchronous control devices for discrete event coordination specified by a Petri net model. The design is based on the compilation of standard circuit modules corresponding to PN fragments into a net modeling PN behavior and on the semantic interpretation of the modeling circuit. The impossibility of asynchronous implementation of the indivisible operation of marking

Victor Varshavsky; Vyacheslav Marakhovsky

1996-01-01

476

Voting behavior under the directional spatial model of electoral competition  

Microsoft Academic Search

This paper contrasts voting behavior in multicandidate elections between the proximity and the directional spatial models of electoral competition. Under the traditionalproximity spatial model, a voter's utility for a candidate is a declining function of distance between their respective positions. Under thedirectional spatial model, introduced by Rabinowitz and Macdonald, utility is specified as the scalar product of the vectors representing

Samuel Merrill III

1993-01-01

477

Modeling the dynamic behavior of supercapacitors using impedance spectroscopy  

Microsoft Academic Search

This paper presents a new approach of modeling the dynamic behavior of supercapacitors using impedance spectroscopy. The new Matlab\\/Simulink model can be used in simulating the voltage response and energy efficiency, e.g., for automotive power systems. The model in the frequency domain, the parameter calculation, as well as the inverse transformation into the time domain are discussed. Furthermore, simulation results

S. Buller; E. Karden; D. Kok; R. W. De Doncker

2002-01-01

478

MAS behavior modeling of virtual drone entity based on CLIPS  

Microsoft Academic Search

MAS is currently a popular method of behavior modeling .it is based on such mathematical model as finite state machine, expert system and soft computing which includes fuzzy logic, neural network, genetic algorithms etc. CLIPS has characteristic of function and nimble implement. If using it as mathematical model of agent, it will be convenient in plan and implement. In this

Hongge Yao

2011-01-01

479

The behavioral approach to silicon carbide power components modeling  

NASA Astrophysics Data System (ADS)

The behavioral and circuit equivalent models applied to silicon carbide semiconductor power devices have been presented. The MOSFET and Merged PiN Schottky diode (MPS) including dynamic electro-thermal modeling have been described in details. The authors also show the problems of the active power estimation for dynamic SiC MPS diode and unrealistic results for manufacturer-provided models.

Zubert, Mariusz; Napieralski, Andrzej; Napieralska, Ma?gorzata; Jab?o?ski, Grzegorz; Starzak, ?ukasz; Janicki, Marcin

2013-07-01

480

Mathematical Models and the Experimental Analysis of Behavior  

ERIC Educational Resources Information Center

The use of mathematical models in the experimental analysis of behavior has increased over the years, and they offer several advantages. Mathematical models require theorists to be precise and unambiguous, often allowing comparisons of competing theories that sound similar when stated in words. Sometimes different mathematical models may make…

Mazur, James E.

2006-01-01

481

Mathematical Models and the Experimental Analysis of Behavior  

Microsoft Academic Search

The use of mathematical models in the experimental analysis of behavior has increased over the years, and they offer several advantages. Mathematical models require theorists to be precise and unambiguous, often allowing comparisons of competing theories that sound similar when stated in words. Sometimes different mathematical models may make equally accurate predictions for a large body of data. In such

JAMES E. MAZUR

2006-01-01

482

Introduction to Modeling Fish Migratory Behavior.  

National Technical Information Service (NTIS)

A few of the basic modeling techniques appropriate to fish migration are reviewed. The biased lattice random walk model and the advection-diffusion model are discussed and illustrated in some depth because these seem to be both practical to use and capabl...

D. L. DeAngelis G. T. Yeh

1982-01-01

483

Efficiencies and coefficients of performance of heat engines, refrigerators, and heat pumps with friction: a universal limiting behavior.  

PubMed

For work-producing heat engines, or work-consuming refrigerators and heat pumps, the percentage decrease caused by friction in their efficiencies, or coefficients of performance (COP's), is approximately given by the ratio W(fric)/W between the work spent against friction forces and the work performed by, or delivered to, the working fluid. This universal scaling, which applies in the limit of small friction (W(fric)/W engine's figures of merit (FOM's, either efficiencies or COP's) do not come too close to unity (no higher than,