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1

Gilbert's Behavior Engineering Model: Contemporary Support for an Established Theory  

ERIC Educational Resources Information Center

This study was an effort to add to the body of research surrounding Gilbert's Behavior Engineering Model (BEM). The model was tested to determine its ability to explain factor relationships of organizational safety culture in a high-risk work environment. Three contextual variables were measured: communication, resource availability, and…

Crossman, Donna Cangelosi

2010-01-01

2

The Virtual Office: A Behavior Engineering Model (BEM) Perspective.  

ERIC Educational Resources Information Center

Discusses issues associated with the virtual office. Summarizes advantages and disadvantages from employees' and employers' perspectives. Uses the behavior engineering model (Thomas Gilbert, 1996) as a framework to analyze different factors related to performance, and suggests the application of other concepts from human performance technology and…

Austin, John; Garnier, Luis

1998-01-01

3

Development of Fabric Constitutive Behavior for Use in Modeling Engine Fan Blade-Out Events  

E-print Network

Development of Fabric Constitutive Behavior for Use in Modeling Engine Fan Blade-Out Events S and reliable material model for fabrics used to prevent fan blade-out events in propulsion engines has significant importance in the design of fan-containment systems. Currently, Kevlar is the only fabric approved

Mobasher, Barzin

4

Modeling and Predicting the Task-by-Task Behavior of Search Engine Users  

E-print Network

Modeling and Predicting the Task-by-Task Behavior of Search Engine Users Claudio Lucchese ISTI for profit or commercial advantage and that copies bear this notice and the full citation on the first page]. To clarify this better, let us consider the user Alice issu- ing the queries "new york hotel" and "waldorf

Orlando, Salvatore

5

Uncertainty and sensitivity analysis of fission gas behavior in engineering-scale fuel modeling  

SciTech Connect

The role of uncertainties in fission gas behavior calculations as part of engineering-scale nuclear fuel modeling is investigated using the BISON fuel performance code and a recently implemented physics-based model for the coupled fission gas release and swelling. Through the integration of BISON with the DAKOTA software, a sensitivity analysis of the results to selected model parameters is carried out based on UO2 single-pellet simulations covering different power regimes. The parameters are varied within ranges representative of the relative uncertainties and consistent with the information from the open literature. The study leads to an initial quantitative assessment of the uncertainty in fission gas behavior modeling with the parameter characterization presently available. Also, the relative importance of the single parameters is evaluated. Moreover, a sensitivity analysis is carried out based on simulations of a fuel rod irradiation experiment, pointing out a significant impact of the considered uncertainties on the calculated fission gas release and cladding diametral strain. The results of the study indicate that the commonly accepted deviation between calculated and measured fission gas release by a factor of 2 approximately corresponds to the inherent modeling uncertainty at high fission gas release. Nevertheless, higher deviations may be expected for values around 10% and lower. Implications are discussed in terms of directions of research for the improved modeling of fission gas behavior for engineering purposes.

G. Pastore; L.P. Swiler; J.D. Hales; S.R. Novascone; D.M. Perez; B.W. Spencer; L. Luzzi; P. Van Uffelen; R.L. Williamson

2014-10-01

6

Uncertainty and sensitivity analysis of fission gas behavior in engineering-scale fuel modeling  

NASA Astrophysics Data System (ADS)

The role of uncertainties in fission gas behavior calculations as part of engineering-scale nuclear fuel modeling is investigated using the BISON fuel performance code with a recently implemented physics-based model for fission gas release and swelling. Through the integration of BISON with the DAKOTA software, a sensitivity analysis of the results to selected model parameters is carried out based on UO2 single-pellet simulations covering different power regimes. The parameters are varied within ranges representative of the relative uncertainties and consistent with the information in the open literature. The study leads to an initial quantitative assessment of the uncertainty in fission gas behavior predictions with the parameter characterization presently available. Also, the relative importance of the single parameters is evaluated. Moreover, a sensitivity analysis is carried out based on simulations of a fuel rod irradiation experiment, pointing out a significant impact of the considered uncertainties on the calculated fission gas release and cladding diametral strain. The results of the study indicate that the commonly accepted deviation between calculated and measured fission gas release by a factor of 2 approximately corresponds to the inherent modeling uncertainty at high fission gas release. Nevertheless, significantly higher deviations may be expected for values around 10% and lower. Implications are discussed in terms of directions of research for the improved modeling of fission gas behavior for engineering purposes.

Pastore, Giovanni; Swiler, L. P.; Hales, J. D.; Novascone, S. R.; Perez, D. M.; Spencer, B. W.; Luzzi, L.; Van Uffelen, P.; Williamson, R. L.

2015-01-01

7

Qualitative and temporal reasoning in engine behavior analysis  

NASA Technical Reports Server (NTRS)

Numerical simulation models, engine experts, and experimental data are used to generate qualitative and temporal representations of abnormal engine behavior. Engine parameters monitored during operation are used to generate qualitative and temporal representations of actual engine behavior. Similarities between the representations of failure scenarios and the actual engine behavior are used to diagnose fault conditions which have already occurred, or are about to occur; to increase the surveillance by the monitoring system of relevant engine parameters; and to predict likely future engine behavior.

Dietz, W. E.; Stamps, M. E.; Ali, M.

1987-01-01

8

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. PMID:18720007

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

9

Through the Use of Gilbert's Behavioral Engineering Model, What Changes Can Management Make to Increase Blood Donations?  

ERIC Educational Resources Information Center

The mixed method study focused on increasing blood donations from staff who work in a blood collecting organization and relies on Gilbert's Behavior Engineering Model as a framework. The qualitative phase of the study involved focus groups. Information from the focus groups and the literature review were used to create hypotheses. A survey was…

Russell, Heather Gordy

2010-01-01

10

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

11

Human Behavior Models for Agents in Simulators and Games: Part II: Gamebot Engineering with PMFserv  

Microsoft Academic Search

Many producers and consumers of legacy training simulator and game environments are beginning to envision a new era where psych-socio-physiologic models could be inter- operated to enhance their environments' simulation of human agents. This article explores whether we could embed our behavior modeling framework (described in Part I) behind a legacy first person shooter 3-D game environment to recreate portions

Barry G. Silverman; Gnana Bharathy; Kevin O'brien; Jason Cornwell

2006-01-01

12

Modeling the structural behavior of the piston rings under different boundary conditions in internal combustion engines  

E-print Network

In the process of designing internal combustion engine, piston ring plays an important role in fulfilling the requirements of camber gas sealing, friction reduction and lubrication oil consumption. The goal of this thesis ...

Xu, Dian

2010-01-01

13

APPLICATION OF CENTRIFUGE MODELING IN GEOTECHNICAL ENGINEERING  

E-print Network

investigation, experimental soil mechanics and centrifuge modeling. He had wide research experiences in both static and dynamic soil-structure interaction problems including mechanical behavior of underground, International Society for Soil Mechanics and Geotechnical Engineering, Japan Society of Civil Engineers

Kamat, Vineet R.

14

Human Behavior Models for Agents in Simulators and Games: Part II Gamebot Engineering with PMFserv  

Microsoft Academic Search

ABSTRACT Many producers and consumers,of legacy training simulator and game environments,are beginning to envision a new era where psych-socio-physiologic models could be inter- operated to enhance their environments' simulation of human agents. This article explores whether we could embed,our behaviormodeling,framework,(described in Part I) behind a legacy first person shooter 3-D game environment,torecreate portions of the Black Hawk Down scenario. Section

Barry G. Silverman; Gnana K. Bharathy; Kevin O'Brien; Jason Cornwell

15

Towards Behavioral Reflexion Models  

NASA Technical Reports Server (NTRS)

Software architecture has become essential in the struggle to manage today s increasingly large and complex systems. Software architecture views are created to capture important system characteristics on an abstract and, thus, comprehensible level. As the system is implemented and later maintained, it often deviates from the original design specification. Such deviations can have implication for the quality of the system, such as reliability, security, and maintainability. Software architecture compliance checking approaches, such as the reflexion model technique, have been proposed to address this issue by comparing the implementation to a model of the systems architecture design. However, architecture compliance checking approaches focus solely on structural characteristics and ignore behavioral conformance. This is especially an issue in Systems-of- Systems. Systems-of-Systems (SoS) are decompositions of large systems, into smaller systems for the sake of flexibility. Deviations of the implementation to its behavioral design often reduce the reliability of the entire SoS. An approach is needed that supports the reasoning about behavioral conformance on architecture level. In order to address this issue, we have developed an approach for comparing the implementation of a SoS to an architecture model of its behavioral design. The approach follows the idea of reflexion models and adopts it to support the compliance checking of behaviors. In this paper, we focus on sequencing properties as they play an important role in many SoS. Sequencing deviations potentially have a severe impact on the SoS correctness and qualities. The desired behavioral specification is defined in UML sequence diagram notation and behaviors are extracted from the SoS implementation. The behaviors are then mapped to the model of the desired behavior and the two are compared. Finally, a reflexion model is constructed that shows the deviations between behavioral design and implementation. This paper discusses the approach and shows how it can be applied to investigate reliability issues in SoS.

Ackermann, Christopher; Lindvall, Mikael; Cleaveland, Rance

2009-01-01

16

The behavioral science contribution to emergency management and engineering  

SciTech Connect

This paper discusses the importance of behavioral science disciplines to emergency management planning and engineering. The authors argue that most emergency response situations, whether simulated or real, occur in systems characterized by both psycho-social and technical components. Those who design emergency systems, whether these are evacuation techniques, decision support technology, fire fighting equipment or other specialized apparatus, often make inexpert assumptions about human behavior. These underlying opinions in turn influence the designers` technical output. Knowledge of the behavioral sciences can provide empirical information, not only on general human response patterns, but about individual and group behavior during emergencies as well. This information allows for more accurate planning and development of system designs. In addition, the behavioral science disciplines can add their empirical tradition to emergency management and engineering, thus providing a template for testing models experimentally.

Kowalski, K.M.; Vaught, C. [Madland Consulting, Bethel Park, PA (United States)

1995-12-31

17

ILLINOIS -RAILROAD ENGINEERING Understanding the Transition Behavior of  

E-print Network

Slide 1 ILLINOIS - RAILROAD ENGINEERING Understanding the Transition Behavior of Railroad Track - RAILROAD ENGINEERING Outline · Introduction · Transition zones · Why study grade crossings? · Grade crossings and US high speed rail · Summary #12;Slide 3 ILLINOIS - RAILROAD ENGINEERING Introduction

Illinois at Urbana-Champaign, University of

18

Model Driven EngineeringModel-Driven Engineering of Industrial  

E-print Network

Model Driven EngineeringModel-Driven Engineering of Industrial P C t l A li tiProcess Control control applications) Engineering challenges Model-Driven Engineering (MDE) A MDE approach for process control applications Case study Discussion Future work Conclusion #12;Introduction Industrial process

Gray, Jeffrey G.

19

Health behavior models compared  

Microsoft Academic Search

This study compares the health belief, Fishbein\\/Ajzen, and PRECEDE models to predict changes in smoking, exercise, and consumption of sweet and fried foods over an eight-month interval. Data were collected from a panel of 326 adults in two large cities of the western United States. The PRECEDE model accounted for more variance in behavior than both the Fishbein\\/Ajzen and health

Patricia D. Mullen; James C. Hersey; Donald C. Iverson

1987-01-01

20

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

21

MODEL OF TOXICANT RESPONSE IN ENGINEERED LIVER  

EPA Science Inventory

This project proposes to: engineer a tissue to mimic liver behavior (a so-called 3-Dimensional or 3D liver model); simulate liver toxicity by exposing the 3D liver model to two known toxicants ( carbon tetrachloride and 1,2 dichloroethylene); and ...

22

Advancements in engineering turbulence modeling  

NASA Technical Reports Server (NTRS)

Some new developments in two-equation models and second order closure models are presented. Two-equation models (k-epsilon models) have been widely used in computational fluid dynamics (CFD) for engineering problems. Most of low-Reynolds number two-equation models contain some wall-distance damping functions to account for the effect of wall on turbulence. However, this often causes the confusion and difficulties in computing flows with complex geometry and also needs an ad hoc treatment near the separation and reattachment points. A set of modified two-equation models is proposed to remove the aforementioned shortcomings. The calculations using various two-equation models are compared with direct numerical simulations of channel flow and flat boundary layers. Development of a second order closure model is also discussed with emphasis on the modeling of pressure related correlation terms and dissipation rates in the second moment equations. All the existing models poorly predict the normal stresses near the wall and fail to predict the 3-D effect of mean flow on the turbulence (e.g. decrease in the shear stress caused by the cross flow in the boundary layer). The newly developed second order near-wall turbulence model is described and is capable of capturing the near-wall behavior of turbulence as well as the effect of 3-D mean flow on the turbulence.

Shih, T.-H.

1991-01-01

23

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

24

Sponsored Search Engines in Competition: Advertisers Behavior and Engines Optimal Ranking  

E-print Network

Sponsored Search Engines in Competition: Advertisers Behavior and Engines Optimal Ranking.Tuffin@inria.fr Abstract--Search engines are essential actors for web browsing. We analyze here the economic competition between search engines earning money from adword auctions. We develop a two- level game where

Paris-Sud XI, Université de

25

Engineering workstation: Sensor modeling  

NASA Technical Reports Server (NTRS)

The purpose of the engineering workstation is to provide an environment for rapid prototyping and evaluation of fusion and image processing algorithms. Ideally, the algorithms are designed to optimize the extraction of information that is useful to a pilot for all phases of flight operations. Successful design of effective fusion algorithms depends on the ability to characterize both the information available from the sensors and the information useful to a pilot. The workstation is comprised of subsystems for simulation of sensor-generated images, image processing, image enhancement, and fusion algorithms. As such, the workstation can be used to implement and evaluate both short-term solutions and long-term solutions. The short-term solutions are being developed to enhance a pilot's situational awareness by providing information in addition to his direct vision. The long term solutions are aimed at the development of complete synthetic vision systems. One of the important functions of the engineering workstation is to simulate the images that would be generated by the sensors. The simulation system is designed to use the graphics modeling and rendering capabilities of various workstations manufactured by Silicon Graphics Inc. The workstation simulates various aspects of the sensor-generated images arising from phenomenology of the sensors. In addition, the workstation can be used to simulate a variety of impairments due to mechanical limitations of the sensor placement and due to the motion of the airplane. Although the simulation is currently not performed in real-time, sequences of individual frames can be processed, stored, and recorded in a video format. In that way, it is possible to examine the appearance of different dynamic sensor-generated and fused images.

Pavel, M; Sweet, B.

1993-01-01

26

Editor's Roundtable: Model behavior  

NSDL National Science Digital Library

Models are manageable representations of objects, concepts, and phenomena, and are everywhere in science. Models are "thinking tools" for scientists and have always played a key role in the development of scientific knowledge. Models of the solar system,

Inez Liftig

2010-11-01

27

Cognitive Architectures for Modeling Driver Behavior Dario D. Salvucci  

E-print Network

architectures can be incorporated into engineering design systems that allow for rapid prototypingCognitive Architectures for Modeling Driver Behavior Dario D. Salvucci Department of Computer-895-2674 To appear in: D. Fisher, M. Rizzo, J. Caird, J. Lee (Eds.), Handbook of Driving Simulation for Engineering

Salvucci, Dario D.

28

Workshop on Engineering Turbulence Modeling  

NASA Technical Reports Server (NTRS)

Discussed here is the future direction of various levels of engineering turbulence modeling related to computational fluid dynamics (CFD) computations for propulsion. For each level of computation, there are a few turbulence models which represent the state-of-the-art for that level. However, it is important to know their capabilities as well as their deficiencies in order to help engineers select and implement the appropriate models in their real world engineering calculations. This will also help turbulence modelers perceive the future directions for improving turbulence models. The focus is on one-point closure models (i.e., from algebraic models to higher order moment closure schemes and partial differential equation methods) which can be applied to CFD computations. However, other schemes helpful in developing one-point closure models, are also discussed.

Povinelli, Louis A. (editor); Liou, W. W. (editor); Shabbir, A. (editor); Shih, T.-H. (editor)

1992-01-01

29

Modeling of nonlinear piezoelectric behavior  

NASA Astrophysics Data System (ADS)

A finite element model for the nonlinear behavior of piezoelectric material is developed. Important issues in modeling the nonlinear behavior of piezoelectric material at micro-scale is discussed and methods to solve such issues are proposed. A procedure is developed to obtain RVE from the simplified microstructure of the material. The RVE is obtained based on a statistical parameter, which is a measure of the degree of heterogeneity at a point. The material properties at the micro-scale are obtained from the macro-scale properties by rule of mixture approach. A finite element iterative solution procedure is then used to model the material behavior by averaging the local response over the entire RVE. Nonlinear behavior of the material is due to the domain switching phenomenon and is simulated based on internal energy density based switching criterion. A numerical example is given for PZT-4 material and the results agree qualitatively with the experimental results.

Achuthan, Ajit; Sun, Chin-Teh

2002-07-01

30

Modelling intelligent behavior  

NASA Technical Reports Server (NTRS)

An introductory discussion of the related concepts of intelligence and consciousness suggests criteria to be met in the modeling of intelligence and the development of intelligent materials. Methods for the modeling of actual structure and activity of the animal cortex have been found, based on present knowledge of the ionic and cellular constitution of the nervous system. These have led to the development of a realistic neural network model, which has been used to study the formation of memory and the process of learning. An account is given of experiments with simple materials which exhibit almost all properties of biological synapses and suggest the possibility of a new type of computer architecture to implement an advanced type of artificial intelligence.

Green, H. S.; Triffet, T.

1993-01-01

31

Modeling Long-Term Search Engine Usage Ryen W. White, Ashish Kapoor, and Susan T. Dumais  

E-print Network

Modeling Long-Term Search Engine Usage Ryen W. White, Ashish Kapoor, and Susan T. Dumais Microsoft engines are key components in the online world and the choice of search engine is an important determinant search engine usage. In particular, we study the engine usage behavior of more than ten thousand users

Dumais, Susan

32

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  

SciTech Connect

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 the hot strip rolling mills and predicts the mechanical properties of hot-rolled products. The HSMM model has been developed by the University of British Columbia-Canada as a part of project on the microstructural engineering in hot-strip mills.

Yi-Wen Cheng; Patrick Purtscher

1999-07-30

33

Engine environmental effects on composite behavior  

NASA Technical Reports Server (NTRS)

A series of programs were conducted to investigate and develop the application of composite materials to turbojet engines. A significant part of that effort was directed to establishing the impact resistance and defect growth chracteristics of composite materials over the wide range of environmental conditions found in commercial turbojet engine operations. Both analytical and empirical efforts were involved. The experimental programs and the analytical methodology development as well as an evaluation program for the use of composite materials as fan exit guide vanes are summarized.

Chamis, C. C.; Smith, G. T.

1980-01-01

34

Towards a Behavioral Software Engineering Per Lenberg  

E-print Network

University Gothenburg, Sweden perle@chalmers.se Robert Feldt Dept. of Software Engineering Blekinge Inst methodologies. As the information systems and tech- nology field (IS/IT) exist in the space between both orga of the groups in which they organize themselves, compared to the number of papers that has a primarily tech

Feldt, Robert

35

Parallel processor engine model program  

NASA Technical Reports Server (NTRS)

The Parallel Processor Engine Model Program is a generalized engineering tool intended to aid in the design of parallel processing real-time simulations of turbofan engines. It is written in the FORTRAN programming language and executes as a subset of the SOAPP simulation system. Input/output and execution control are provided by SOAPP; however, the analysis, emulation and simulation functions are completely self-contained. A framework in which a wide variety of parallel processing architectures could be evaluated and tools with which the parallel implementation of a real-time simulation technique could be assessed are provided.

Mclaughlin, P.

1984-01-01

36

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

37

An Object Model for a Rocket Engine Numerical Simulator  

NASA Technical Reports Server (NTRS)

Rocket Engine Numerical Simulator (RENS) is a packet of software which numerically simulates the behavior of a rocket engine. Different parameters of the components of an engine is the input to these programs. Depending on these given parameters the programs output the behaviors of those components. These behavioral values are then used to guide the design of or to diagnose a model of a rocket engine "built" by a composition of these programs simulating different components of the engine system. In order to use this software package effectively one needs to have a flexible model of a rocket engine. These programs simulating different components then should be plugged into this modular representation. Our project is to develop an object based model of such an engine system. We are following an iterative and incremental approach in developing the model, as is the standard practice in the area of object oriented design and analysis of softwares. This process involves three stages: object modeling to represent the components and sub-components of a rocket engine, dynamic modeling to capture the temporal and behavioral aspects of the system, and functional modeling to represent the transformational aspects. This article reports on the first phase of our activity under a grant (RENS) from the NASA Lewis Research center. We have utilized Rambaugh's object modeling technique and the tool UML for this purpose. The classes of a rocket engine propulsion system are developed and some of them are presented in this report. The next step, developing a dynamic model for RENS, is also touched upon here. In this paper we will also discuss the advantages of using object-based modeling for developing this type of an integrated simulator over other tools like an expert systems shell or a procedural language, e.g., FORTRAN. Attempts have been made in the past to use such techniques.

Mitra, D.; Bhalla, P. N.; Pratap, V.; Reddy, P.

1998-01-01

38

Pulse Detonation Engine Modeled  

NASA Technical Reports Server (NTRS)

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 process, may make Pulse Detonation Engines (PDE's) well suited for a number of mission profiles. Assessment of PDE cycles requires a simulation capability that is both fast and accurate. It should capture the essential physics of the system, yet run at speeds that allow parametric analysis. A quasi-one-dimensional, computational-fluid-dynamics-based simulation has been developed that may meet these requirements. The Euler equations of mass, momentum, and energy have been used along with a single reactive species transport equation, and submodels to account for dominant loss mechanisms (e.g., viscous losses, heat transfer, and valving) to successfully simulate PDE cycles. A high-resolution numerical integration scheme was chosen to capture the discontinuities associated with detonation, and robust boundary condition procedures were incorporated to accommodate flow reversals that may arise during a given cycle. The accompanying graphs compare experimentally measured and computed performance over a range of operating conditions for a particular PDE. Experimental data were supplied by Fred Schauer and Jeff Stutrud from the Air Force Research Laboratory at Wright-Patterson AFB and by Royce Bradley from Innovative Scientific Solutions, Inc. The left graph shows thrust and specific impulse, Isp, as functions of equivalence ratio for a PDE cycle in which the tube is completely filled with a detonable hydrogen/air mixture. The right graph shows thrust and specific impulse as functions of the fraction of the tube that is filled with a stoichiometric mixture of hydrogen and air. For both figures, the operating frequency was 16 Hz. The agreement between measured and computed values is quite good, both in terms of trend and magnitude. The error is under 10 percent everywhere except for the thrust value at an equivalence ratio of 0.8 in the left figure, where it is 14 percent. The simulation results shown were made using 200 numerical cells. Each cycle of the engine, approximately 0.06 sec, required 2.0 min of CPU time on a Sun Ultra2. The simulation is currently being used to analyze existing experiments, design new experiments, and predict performance in propulsion concepts where the PDE is a component (e.g., hybrid engines and combined cycles).

Paxson, Daniel E.

2001-01-01

39

Creep rupture behavior of Stirling engine materials  

NASA Technical Reports Server (NTRS)

The automotive Stirling engine, being investigated jointly by the Department of Energy and NASA Lewis as an alternate to the internal combustion engine, uses high-pressure hydrogen as the working fluid. The long-term effects of hydrogen on the high temperature strength properties of materials is relatively unknown. This is especially true for the newly developed low-cost iron base alloy NASAUT 4G-A1. This iron-base alloy when tested in air has creep-rupture strengths in the directionally solidified condition comparable to the cobalt base alloy HS-31. The equiaxed (investment cast) NASAUT 4G-A1 has superior creep-rupture to the equiaxed iron-base alloy XF-818 both in air and 15 MPa hydrogen.

Titran, R. H.; Scheuerman, C. M.; Stephens, J. R.

1985-01-01

40

Biometrical Models in Behavioral Genetics  

Microsoft Academic Search

The main goal of this chapter is to describe the research designs and statistical methods that are in popular use in behavioral\\u000a genetics (BG). We begin with a brief overview of the historical background to BG in general and twin studies in particular.\\u000a Next, we describe some elementary statistics required for understanding biometrical modeling. Then follows a statistical model\\u000a for

Michael C. Neale

41

Cognitive Modeling of Social Behaviors  

NASA Technical Reports Server (NTRS)

The driving theme of cognitive modeling for many decades has been that knowledge affects how and which goals are accomplished by an intelligent being (Newell 1991). But when one examines groups of people living and working together, one is forced to recognize that whose knowledge is called into play, at a particular time and location, directly affects what the group accomplishes. Indeed, constraints on participation, including roles, procedures, and norms, affect whether an individual is able to act at all (Lave & Wenger 1991; Jordan 1992; Scribner & Sachs 1991). To understand both individual cognition and collective activity, perhaps the greatest opportunity today is to integrate the cognitive modeling approach (which stresses how beliefs are formed and drive behavior) with social studies (which stress how relationships and informal practices drive behavior). The crucial insight is that norms are conceptualized in the individual &nd as ways of carrying out activities (Clancey 1997a, 2002b). This requires for the psychologist a shift from only modeling goals and tasks - why people do what they do - to modeling behavioral patterns-what people do-as they are engaged in purposeful activities. Instead of a model that exclusively deduces actions from goals, behaviors are also, if not primarily, driven by broader patterns of chronological and located activities (akin to scripts). This analysis is particular inspired by activity theory (Leont ev 1979). While acknowledging that knowledge (relating goals and operations) is fundamental for intelligent behavior, activity theory claims that a broader driver is the person s motives and conceptualization of activities. Such understanding of human interaction is normative (i.e., viewed with respect to social standards), affecting how knowledge is called into play and applied in practice. Put another way, how problems are discovered and framed, what methods are chosen, and indeed who even cares or has the authority to act, are all constrained by norms, which are conceived and enacted by individuals.

Clancey, William J.; Sierhuis, Maarten; Damer. Bruce; Brodsky, Boris

2004-01-01

42

Process Modeling (Engineering Statistics Handbook)  

NSDL National Science Digital Library

Created by Alan Heckert and James Filliben, this chapter of the National Institute of Standard and Technology (NIST) Engineering Statistics handbook presents information on the statistical modeling of an engineering process. It contains an introduction, discussion of the assumptions, information about data collection and analysis, a discussion of what can be concluded from different process models, and case studies. This final section is quite interesting. It offers four different studies, they consist of: load cell output, the Alaskan Pipeline, ultrasonic reference block and the thermal expansion of copper. Once students go through the theories presented, the case studies allow them to apply this knowledge.

Filliben, James

43

Stirling Engine Dynamic System Modeling  

NASA Technical Reports Server (NTRS)

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

Nakis, Christopher G.

2004-01-01

44

Dynamic behavior of a magnetic bearing supported jet engine rotor with auxiliary bearings  

NASA Technical Reports Server (NTRS)

This paper presents a study of the dynamic behavior of a rotor system supported by auxiliary bearings. The steady-state behavior of a simulation model based upon a production jet engine is explored over a wide range of operating conditions for varying rotor imbalance, support stiffness and damping. Interesting dynamical phenomena, such as chaos, subharmonic responses, and double-valued responses, are presented and discussed.

Homaifar, Abdollah (editor); Kelly, John C., Jr. (editor); Flowers, G. T.; Xie, H.; Sinha, S. C.

1994-01-01

45

Dynamic behavior of a magnetic bearing supported jet engine rotor with auxiliary bearings  

NASA Technical Reports Server (NTRS)

This paper presents a study of the dynamic behavior of a rotor system supported by auxiliary bearings. The steady-state behavior of a simulation model based upon a production jet engine is explored over a wide range of operating conditions for varying rotor imbalance, support stiffness, and damping. Interesting dynamical phenomena, such as chaos, subharmonic responses, and double-valued responses, are presented and discussed.

Flowers, George T.; Xie, Huajun; Sinha, S. C.

1995-01-01

46

Organizational behavior & software product line engineering: An empirical study  

Microsoft Academic Search

Software product line engineering is an inter-disciplinary concept. It spans over the dimensions of business, architecture, process and organization. Some of the potential benefits of this approach include cost reduction, improvement in quality and a decrease in product development time. Employees' participation, organizational behavior and management contemplation play a vital role in successfully institutionalizing software product lines in a firm.

Faheem Ahmed; Salah Bouktif; Luiz Fernando Capretz

2009-01-01

47

Modeling the internal combustion engine  

Microsoft Academic Search

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

F. J. Zeleznik; B. J. Mcbride

1985-01-01

48

A control systems engineering approach for adaptive behavioral interventions: illustration with a fibromyalgia intervention.  

PubMed

The term adaptive intervention has been used in behavioral medicine to describe operationalized and individually tailored strategies for prevention and treatment of chronic, relapsing disorders. Control systems engineering offers an attractive means for designing and implementing adaptive behavioral interventions that feature intensive measurement and frequent decision-making over time. This is illustrated in this paper for the case of a low-dose naltrexone treatment intervention for fibromyalgia. System identification methods from engineering are used to estimate dynamical models from daily diary reports completed by participants. These dynamical models then form part of a model predictive control algorithm which systematically decides on treatment dosages based on measurements obtained under real-life conditions involving noise, disturbances, and uncertainty. The effectiveness and implications of this approach for behavioral interventions (in general) and pain treatment (in particular) are demonstrated using informative simulations. PMID:25264467

Deshpande, Sunil; Rivera, Daniel E; Younger, Jarred W; Nandola, Naresh N

2014-09-01

49

Model-Driven Useware Engineering  

NASA Astrophysics Data System (ADS)

User-oriented hardware and software development relies on a systematic development process based on a comprehensive analysis focusing on the users' requirements and preferences. Such a development process calls for the integration of numerous disciplines, from psychology and ergonomics to computer sciences and mechanical engineering. Hence, a correspondingly interdisciplinary team must be equipped with suitable software tools to allow it to handle the complexity of a multimodal and multi-device user interface development approach. An abstract, model-based development approach seems to be adequate for handling this complexity. This approach comprises different levels of abstraction requiring adequate tool support. Thus, in this chapter, we present the current state of our model-based software tool chain. We introduce the use model as the core model of our model-based process, transformation processes, and a model-based architecture, and we present different software tools that provide support for creating and maintaining the models or performing the necessary model transformations.

Meixner, Gerrit; Seissler, Marc; Breiner, Kai

50

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

51

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

52

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.

53

A LUMPED-PARAMETER DYNAMIC MODEL OF A THERMAL REGENERATOR FOR FREE-PISTON STIRLING ENGINES  

E-print Network

A LUMPED-PARAMETER DYNAMIC MODEL OF A THERMAL REGENERATOR FOR FREE-PISTON STIRLING ENGINES Mark the mass flow, piston dynamics, and control volume behavior inside a free-piston Stirling engine. A new model for a Stirling engine thermal regenerator that incorporates a dynamically changing temperature

Barth, Eric J.

54

NASA/DoD Aerospace Knowledge Diffusion Research Project. Paper 31: The information-seeking behavior of engineers  

NASA Technical Reports Server (NTRS)

Engineers are an extraordinarily diverse group of professionals, but an attribute common to all engineers is their use of information. Engineering can be conceptualized as an information processing system that must deal with work-related uncertainty through patterns of technical communications. Throughout the process, data, information, and tacit knowledge are being acquired, produced, transferred, and utilized. While acknowledging that other models exist, we have chosen to view the information-seeking behavior of engineers within a conceptual framework of the engineer as an information processor. This article uses the chosen framework to discuss information-seeking behavior of engineers, reviewing selected literature and empirical studies from library and information science, management, communications, and sociology. The article concludes by proposing a research agenda designed to extend our current, limited knowledge of the way engineers process information.

Pinelli, Thomas E.; Bishop, Ann P.; Barclay, Rebecca O.; Kennedy, John M.

1993-01-01

55

A New Prediction Model Based on Belief Rule Base for System's Behavior Prediction  

Microsoft Academic Search

In engineering practice, a system's behavior con- stantly changes over time. To predict the behavior of a complex engineering system, a model can be built and trained using his- torical data. This paper addresses the forecasting problems with a belief rule base (BRB) to trace and predict system performance in a more interpretable and transparent way. More precisely, it extends

Xiao-Sheng Si; Chang-Hua Hu; Jian-Bo Yang; Zhi-Jie Zhou

2011-01-01

56

A Simple Model of Search Engine Pricing  

Microsoft Academic Search

We present a simple model of how a monopolistic search engine optimally determines the average relevance of firms in its search pool. In our model, there is a continuum of consumers, who use the search engine's pool, and there is a continuum of firms, whose entry to the pool is restricted by a price?per?click set by the search engine. We

Kfir Eliaz; Ran Spiegler

2011-01-01

57

Modeling in Microwave Power Engineering: Methods & Applications  

E-print Network

antenna), import/export of files, control over QW operations from MATLAB, modeling of moving objectsModeling in Microwave Power Engineering: Methods & Applications A Part of the Graduate Course and processes in microwave power engineering and shows what modern advanced simulation can bring to engineers

Yakovlev, Vadim

58

Optimization of a model external combustion engine  

Microsoft Academic Search

Using the Pontryagin maximum principle we optimize the operating conditions of a model external-combustion engine to obtain maximal efficiency. The model engine consists of a cylinder equipped with a piston containing a gas, pumped with a given time-dependent rate of heating, and coupled to a heat bath. We consider a fully cyclic engine, wherein both the volume and the energy

Yehuda B. Band; Oded Kafri; Peter Salamon

1982-01-01

59

Quantitative Modeling of Polymer Scratch Behavior  

E-print Network

dependent mechanical behavior and pressure dependent frictional behavior in the FEM model, good agreement has been found between FEM simulation and experimental observations. The results suggest that, by including proper constitutive relationship...

Hossain, Mohammad Motaher

2013-12-02

60

Modeling the internal combustion engine  

NASA Technical Reports Server (NTRS)

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.

1985-01-01

61

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. PMID:19368523

Robinson, Paul S.

2009-01-01

62

Establishment of Computational Models for Clothing Engineering Design  

Microsoft Academic Search

Clothing design achieved by engineering framework and method is a newly interest in the state of art of textile research, which may create many advantages, such as improving the design efficiency and strengthening the ability to consider more issues. The mathematical models describing the behind physical and chemical mechanisms of the involved various behaviors inside the textile materials and the

MAO AIHUA; WANG RUOMEI; Amo Aihua; Li Yi; Lou Xiaonan

63

Coupling of Mechanical Behavior of Cell Components to Electrochemical-Thermal Models for Computer-Aided Engineering of Batteries under Abuse (Presentation)  

SciTech Connect

The EV Everywhere Grand Challenge aims to produce plug-in electric vehicles as affordable and convenient for the American family as gasoline-powered vehicles by 2022. Among the requirements set by the challenge, electric vehicles must be as safe as conventional vehicles, and EV batteries must not lead to unsafe situations under abuse conditions. NREL's project started in October 2013, based on a proposal in response to the January 2013 DOE VTO FOA, with the goal of developing computer aided engineering tools to accelerate the development of safer lithium ion batteries.

Pesaran, A.; Wierzbicki, T.; Sahraei, E.; Li, G.; Collins, L.; Sprague, M.; Kim, G. H.; Santhangopalan, S.

2014-06-01

64

Mathematical modeling of catalytic converter lightoff; Part II: model verification by engine-dynamometer experiments  

Microsoft Academic Search

A transient mathematical model has been developed which describes the behavior of packed-bed catalytic converters during warmup. Model predictions agree very well with the results of engine-dynamometer experiments for three Pt-alumina catalysts of widely different properties, thus demonstrating the validity of the model.

S. H. Oh; J. C. Cavendish

1985-01-01

65

Engine Structures Modeling Software System (ESMOSS)  

NASA Technical Reports Server (NTRS)

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

1991-01-01

66

Thermodynamic modeling of pseudoternary phase behavior  

SciTech Connect

Phase behavior is the fulcrum at which the chemistry and physics of surfactant and solvent systems govern the engineering and economics of chemical flooding. Salient behavior is represented by pseudoternary diagrams that account for polar, nonpolar, and amphiphilic components. The common 2/sub -/, 3, 2/sup -/, phase-split progression--induced, for example, by salinity change in microemulsion systems--is required by thermodynamic principles. Although such progressions can be simulated semiempirically, modeling them with a suitable free energy function or an equation of mixture state is more reliable for interpolating and extrapolating limited data on phase splits and coexisting phase compositions for use in mechanism-based computer simulation of laboratory experiments and field applications. Simple equations of mixture state prove inadequate but lead to the promising new linearly screened FloryHuggins (LSFH) equation, which accounts for simultaneous association of amphiphile with oil and water and aggregation of surfactant amphiphile into curved sheetlike structures that separate water-rich from oil-rich regions.

Rossen, W.R.; Brown, R.G.; Davis, H.T.; Prager, S.; Scriven, L.E.

1982-12-01

67

Thermodynamic modeling of pseudoternary phase behavior  

SciTech Connect

Phase behavior is the fulcrum at which the chemistry and physics of surfactant and solvent systems govern the engineering and economics of chemical flooding. Salient behavior is represented by pseudoternary diagrams that account for polar, nonpolar, and amphiphilic components. The common 2, 3, 2, phase-split progression--induced, for example, by salinity change in microemulsion systems--is required by thermodynamic principles. Although such progressions can be simulated semiempirically, modeling them with a suitable free energy function or an equation of mixture state is more reliable for interpolating and extrapolating limited data on phase splits and coexisting phase compositions for use in mechanism-based computer simulation of laboratory experiments and field applications. Simple equations of mixture state prove inadequate but lead to the promising new linearly screened. FloryHuggins (LSFH) equation, which accounts for simultaneous association of amphiphile with oil and water and aggregation of surfactant amphiphile into curved sheetlike structures that separate water-rich from oil-rich regions. From this equation for a ternary mixture are calculated representative sets of diagrams with continuous progressions of tielines and binodals, plait points, tie-triangles, and three-phase regions with their critical endpoints. Several overlapping regions of metastable one- and two-phase equilibria are identified. Free-energy surfaces are pictured, and the free-energy factor that jointly controls interfacial tension (IFT) is computed. Ultralow tensions are favored by low-relief free-energy surfaces; so also are long-lived metastable states.

Rossen, W.R.; Brown, R.G.; Davis, H.T.; Prager, S.; Scriven, L.E.

1982-12-01

68

Dynamic Modeling of Magnetorheological Damper Behaviors  

Microsoft Academic Search

Based on theoretical analysis and experiments, this article proposes a new model for a magnetorheological (MR) damper. The proposed model with a smooth and concise form can interpret the bi-viscous and hysteretic behaviors of the MR damper very well. The parameters in the model have definite physical meanings. The bi-viscous and hysteretic behaviors can be characterized by two parameters 0

Shuqi Guo; Shaopu Yang; Cunzhi Pan

2006-01-01

69

Distributed Behavioral Models: Analysis and Application  

Microsoft Academic Search

show that this model not only looks good but can be made to be quantifiably close to actual animal behavior. We feel that applica- tions such as computer graphics and automated steering will be improved by requiring the model be biologically accurate. 4.2 Starling Behaviors Modeled D UE TO an abundant amount of video footage, we will use the European

Pavlo Cherepanov; Jason Damazo; Collin Powell; Kye Taylor

70

Covert Modeling, Imagery Assessment, and Assertive Behavior  

ERIC Educational Resources Information Center

The purpose of the present investigation was (a) to examine the effect of two variables in developing assertive behavior using covert modeling and (b) to develop a technique to assess ongoing imagery during treatment. The results indicated that imagining multiple models or model reinforcement enhanced behavior change. (Author)

Kazdin, Alan E.

1975-01-01

71

Performance Modeling of Stochastic Diagnosis Engines  

E-print Network

.jsc.nasa.gov. #12;Performance Modeling of Stochastic Diagnosis Engines Author: T.P.M. Janssen Student id: 1053469Performance Modeling of Stochastic Diagnosis Engines T.P.M. Janssen #12;#12;Performance Modeling of MASTER OF SCIENCE in COMPUTER SCIENCE by T.P.M. Janssen born in Nijmegen, the Netherlands Software

Kuzmanov, Georgi

72

The Limits of Phenomenology: From Behaviorism to Drug Testing and Engineering Design  

E-print Network

It is widely believed that theory is useful in physics because it describes simple systems and that strictly empirical phenomenological approaches are necessary for complex biological and social systems. Here we prove based upon an analysis of the information that can be obtained from experimental observations that theory is even more essential in the understanding of complex systems. Implications of this proof revise the general understanding of how we can understand complex systems including the behaviorist approach to human behavior, problems with testing engineered systems, and medical experimentation for evaluating treatments and the FDA approval of medications. Each of these approaches are inherently limited in their ability to characterize real world systems due to the large number of conditions that can affect their behavior. Models are necessary as they can help to characterize behavior without requiring observations for all possible conditions. The testing of models by empirical observations enhance...

Bar-Yam, Yaneer

2013-01-01

73

Covert modeling, imagery assessment, and assertive behavior  

Microsoft Academic Search

Conducted an investigation to (a) examine the effect of 2 variables in developing assertive behavior using covert modeling and (b) develop a technique to assess ongoing imagery during treatment. Ss were 54 18-61 yr olds. In a 2 * 2 design, the number of models imagined (imagining several models vs imagining a single model perform assertively) and model reinforcement (imagining

Alan E. Kazdin

1975-01-01

74

Optimization of a model internal combustion engine  

Microsoft Academic Search

We optimize the operating conditions of a model internal combustion engine to obtain maximal efficiency. The model engine consists of a cylinder equipped with a piston containing a working fluid, coupled to a heat bath and heated by internal combustion with a rate of heating that is very weakly dependent on the temperature and pressure of the working fluid. We

Boris M. Aizenbud; Yehuda B. Band; Oded Kafri

1982-01-01

75

Uranus Atmospheric Model for Engineering Application  

NASA Astrophysics Data System (ADS)

Trajectory simulation of an entry vehicle requires an atmospheric model based upon current scientific understanding. A new engineering atmospheric model based upon Voyager-2 data was developed for Uranus that could be used for entry simulations.

Allen, G. A.; Marley, M. S.; Agrawal, P.

2014-07-01

76

Cognitive engineering models in space systems  

NASA Technical Reports Server (NTRS)

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

Mitchell, Christine M.

1993-01-01

77

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

78

Parametric Model of an Aerospike Rocket Engine  

NASA Technical Reports Server (NTRS)

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 generate the aerospike engine performance tables for axial thrust, normal thrust, pitching moment, and specific thrust. Parametric engine geometry was defined for use with the engine simulator module. The parametric model was also integrated into the iSIGHTI multidisciplinary framework so that alternate designs could be determined. The computer codes were used to support in-house conceptual studies of reusable launch vehicle designs.

Korte, J. J.

2000-01-01

79

Parametric Model of an Aerospike Rocket Engine  

NASA Technical Reports Server (NTRS)

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 generate the aerospike engine performance tables for axial thrust, normal thrust, pitching moment, and specific thrust. Parametric engine geometry was defined for use with the engine simulator module. The parametric model was also integrated into the iSIGHT multidisciplinary framework so that alternate designs could be determined. The computer codes were used to support in-house conceptual studies of reusable launch vehicle designs.

Korte, J. J.

2000-01-01

80

75 FR 68179 - Airworthiness Directives; Austro Engine GmbH Model E4 Diesel Piston Engines  

Federal Register 2010, 2011, 2012, 2013, 2014

...Austro Engine GmbH Model E4 Diesel Piston Engines AGENCY: Federal Aviation...Austro Engine GmbH model E4 diesel piston engines. These engines are installed...information. Contact Austro Engine GmbH, Rudolf-Diesel- Strasse 11, A-2700...

2010-11-05

81

Financial Models for Integrated Behavioral Health Care  

Microsoft Academic Search

Integrated behavioral health care or “integrated care” is a distinct service delivery model aimed at early identification and appropriate intervention with that portion of medical\\/surgical patients presenting with behavioral health issues. The clinical rationale for integrated care and the potential for medical cost offset savings have been clearly substantiated in available research (Cummings, 2007; O’Donohue, Ferguson & Cummings, 2002), but

Blake Chaffee

82

A Behavioral Model of Rational Choice  

Microsoft Academic Search

This article by Herbert Simon provided one of the leading alternatives to the traditional model of rational profit-maximizing behavior, bringing to the forefront of academic attention several of the key issues on which behavioral economics would eventually focus. Introduction by Lindsay McSweeney, Competition Policy International.

Herbert A. Simon; Lindsay McSweeney

2010-01-01

83

Modeling Ant Behavior Under a Variable Environment  

E-print Network

Modeling Ant Behavior Under a Variable Environment Karla Vittori1 , Jacques Gautrais2 , Aluizio F.61.55.67.31, Fax: (033) 5.61.55. 61.54 theraula@cict.fr Abstract. This paper studies the behavior of ants when source. The ant responses when temporarily blocking the access to some branches of the maze were observed

Theraulaz, Guy

84

Micromechanical modeling of rough interface behavior  

E-print Network

In this dissertation, the interface behavior of contacting rough surfaces was studied systematically based upon micromechanical modeling. Firstly, asperity contact mechanics was further developed. It was found that tangential tractions, displacement...

Huang, Shiping

2011-07-28

85

Domain and Specification Models for Software Engineering  

NASA Technical Reports Server (NTRS)

This paper discusses our approach to representing application domain knowledge for specific software engineering tasks. Application domain knowledge is embodied in a domain model. Domain models are used to assist in the creation of specification models. Although many different specification models can be created from any particular domain model, each specification model is consistent and correct with respect to the domain model. One aspect of the system-hierarchical organization is described in detail.

Iscoe, Neil; Liu, Zheng-Yang; Feng, Guohui

1992-01-01

86

Combustion Modeling in Internal Combustion Engines  

Microsoft Academic Search

The fundamental assumptions of the Blizard and Keck combustion model for internal combustion engines are examined and a generalization of that model is derived. The most significant feature of the model is that it permits the occurrence of unburned hydrocarbons in the thermodynamic-kinetic modeling of exhaust gases. The general formulas are evaluated in two specific cases that are likely to

FRANK J. ZELEZNIK

1976-01-01

87

Laser docking sensor engineering model  

NASA Technical Reports Server (NTRS)

NASA JSC has been involved in the development of Laser sensors for the past ten years in order to support future rendezvous and docking missions, both manned and unmanned. Although many candidate technologies have been breadboarded and evaluated, no sensor hardware designed specifically for rendezvous and docking applications has been demonstrated on-orbit. It has become apparent that representative sensors need to be flown and demonstrated as soon as possible, with minimal cost, to provide the capability of the technology in meeting NASA's future AR&C applications. Technology and commercial component reliability have progressed to where it is now feasible to fly hardware as a detailed test objective minimizing the overall cost and development time. This presentation will discuss the ongoing effort to convert an existing in-house developed breadboard to an engineering model configuration suitable for flight. The modifications include improving the ranger resolution and stability with an in-house design, replacing the rack mounted galvanometric scanner drivers with STD-bus cards, replacing the system controlling personal computer with a microcontroller, and repackaging the subsystems as appropriate. The sensor will use the performance parameters defined in previous JSC requirements working groups as design goals and be built to withstand the space environment where fiscally feasible. Testing of the in-house ranger design is expected to be completed in October. The results will be included in the presentation. Preliminary testing of the ranging circuitry indicates a range resolution of 4mm is possible. The sensor will be mounted in the payload bay on a shelf bracket and have command, control, and display capabilities using the payload general support computer via an RS422 data line.

Dekome, Kent; Barr, Joseph M.

1991-01-01

88

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

89

An EHF telecommunication system engineering model  

Microsoft Academic Search

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

Kenneth C. Allen

1987-01-01

90

Reverse Engineering Goal Models from Legacy Code  

Microsoft Academic Search

A reverse engineering process aims at reconstructing high-level abstractions from source code. This paper presents a novel reverse engineering methodology for re- covering stakeholder goal models from both structured and unstructured legacy code. The methodology consists of the following major steps: 1) Refactoring source code by extracting methods based on comments; 2) Convert- ing the refactored code into an abstract

Yijun Yu; Yiqiao Wang; John Mylopoulos; Sotirios Liaskos; Alexei Lapouchnian; Julio Cesar Sampaio Do Prado Leite

2005-01-01

91

Behavioral circuit modeling using neural networks  

Microsoft Academic Search

A technique is presented for automatic generation of Analog Behavioral circuit models using feed-forward neural networks in static and dynamic configurations. These models are generated, by using the data output from an accurate SPICE simulation to train a neural network to model a particular circuit function. Results are given using two types of neural networks, a static neural network to

Stephen V. Kosonocky

1994-01-01

92

Complete modeling for systems of a marine diesel engine  

NASA Astrophysics Data System (ADS)

This paper presents a simulator model of a marine diesel engine based on physical, semi-physical, mathematical and thermodynamic equations, which allows fast predictive simulations. The whole engine system is divided into several functional blocks: cooling, lubrication, air, injection, combustion and emissions. The sub-models and dynamic characteristics of individual blocks are established according to engine working principles equations and experimental data collected from a marine diesel engine test bench for SIMB Company under the reference 6M26SRP1. The overall engine system dynamics is expressed as a set of simultaneous algebraic and differential equations using sub-blocks and S-Functions of Matlab/Simulink. The simulation of this model, implemented on Matlab/Simulink has been validated and can be used to obtain engine performance, pressure, temperature, efficiency, heat release, crank angle, fuel rate, emissions at different sub-blocks. The simulator will be used, in future work, to study the engine performance in faulty conditions, and can be used to assist marine engineers in fault diagnosis and estimation (FDI) as well as designers to predict the behavior of the cooling system, lubrication system, injection system, combustion, emissions, in order to optimize the dimensions of different components. This program is a platform for fault simulator, to investigate the impact on sub-blocks engine's output of changing values for faults parameters such as: faulty fuel injector, leaky cylinder, worn fuel pump, broken piston rings, a dirty turbocharger, dirty air filter, dirty air cooler, air leakage, water leakage, oil leakage and contamination, fouling of heat exchanger, pumps wear, failure of injectors (and many others).

Nahim, Hassan Moussa; Younes, Rafic; Nohra, Chadi; Ouladsine, Mustapha

2015-01-01

93

Complete modeling for systems of a marine diesel engine  

NASA Astrophysics Data System (ADS)

This paper presents a simulator model of a marine diesel engine based on physical, semi-physical, mathematical and thermodynamic equations, which allows fast predictive simulations. The whole engine system is divided into several functional blocks: cooling, lubrication, air, injection, combustion and emissions. The sub-models and dynamic characteristics of individual blocks are established according to engine working principles equations and experimental data collected from a marine diesel engine test bench for SIMB Company under the reference 6M26SRP1. The overall engine system dynamics is expressed as a set of simultaneous algebraic and differential equations using sub-blocks and S-Functions of Matlab/Simulink. The simulation of this model, implemented on Matlab/Simulink has been validated and can be used to obtain engine performance, pressure, temperature, efficiency, heat release, crank angle, fuel rate, emissions at different sub-blocks. The simulator will be used, in future work, to study the engine performance in faulty conditions, and can be used to assist marine engineers in fault diagnosis and estimation (FDI) as well as designers to predict the behavior of the cooling system, lubrication system, injection system, combustion, emissions, in order to optimize the dimensions of different components. This program is a platform for fault simulator, to investigate the impact on sub-blocks engine's output of changing values for faults parameters such as: faulty fuel injector, leaky cylinder, worn fuel pump, broken piston rings, a dirty turbocharger, dirty air filter, dirty air cooler, air leakage, water leakage, oil leakage and contamination, fouling of heat exchanger, pumps wear, failure of injectors (and many others).

Nahim, Hassan Moussa; Younes, Rafic; Nohra, Chadi; Ouladsine, Mustapha

2015-03-01

94

Modeling Off-Nominal Behavior in SysML  

NASA Technical Reports Server (NTRS)

Fault Management is an essential part of the system engineering process that is limited in its effectiveness by the ad hoc nature of the applied approaches and methods. Providing a rigorous way to develop and describe off-nominal behavior is a necessary step in the improvement of fault management, and as a result, will enable safe, reliable and available systems even as system complexity increases... The basic concepts described in this paper provide a foundation to build a larger set of necessary concepts and relationships for precise modeling of off-nominal behavior, and a basis for incorporating these ideas into the overall systems engineering process.. The simple FMEA example provided applies the modeling patterns we have developed and illustrates how the information in the model can be used to reason about the system and derive typical fault management artifacts.. A key insight from the FMEA work was the utility of defining failure modes as the "inverse of intent", and deriving this from the behavior models.. Additional work is planned to extend these ideas and capabilities to other types of relevant information and additional products.

Day, John; Donahue, Kenny; Ingham, Mitch; Kadesch, Alex; Kennedy, Kit; Post, Ethan

2012-01-01

95

Behavior Modeling with Interaction Diagrams in a UML and OCL Tool  

E-print Network

set. Categories and Subject Descriptors D.2.2 [Software engineering]: Design Tools and Tech- niques--Object-oriented design methods; D.2.4 [Software engineering]: Software/Program Verification--Validation; F.3.1 [LogicsBehavior Modeling with Interaction Diagrams in a UML and OCL Tool Martin Gogolla, Lars Hamann

Gogolla, Martin - Fachbereich 3

96

Outer planet probe engineering model structural tests  

NASA Technical Reports Server (NTRS)

A series of proof of concept structural tests was performed on an engineering model of the Outer Planets Atmospheric Entry Probe. The tests consisted of pyrotechnic shock, dynamic and static loadings. The tests partially verified the structural concept.

Smittkamp, J. A.; Gustin, W. H.; Griffin, M. W.

1977-01-01

97

A game theory-based analysis of search engine non-neutral behavior  

E-print Network

A game theory-based analysis of search engine non-neutral behavior Luis Guijarro, Vicent Pla, Bruno the policy of major search engines, and more specifically about their ranking in so-called organic results: the payment by content providers to the search engine in order to improve the chances to be located

Paris-Sud XI, Université de

98

Hierarchical representation and machine learning from faulty jet engine behavioral examples to detect real time abnormal conditions  

NASA Technical Reports Server (NTRS)

The theoretical basis and operation of LEBEX, a machine-learning system for jet-engine performance monitoring, are described. The behavior of the engine is modeled in terms of four parameters (the rotational speeds of the high- and low-speed sections and the exhaust and combustion temperatures), and parameter variations indicating malfunction are transformed into structural representations involving instances and events. LEBEX extracts descriptors from a set of training data on normal and faulty engines, represents them hierarchically in a knowledge base, and uses them to diagnose and predict faults on a real-time basis. Diagrams of the system architecture and printouts of typical results are shown.

Gupta, U. K.; Ali, M.

1988-01-01

99

Ab-initio Calculations to Model Anomalous Fluorine Behavior Milan Diebel1  

E-print Network

Ab-initio Calculations to Model Anomalous Fluorine Behavior Milan Diebel1 and Scott T. Dunham2 1 Engineering, University of Washington, Seattle, WA 98195-2500, USA ABSTRACT Implanted fluorine has been motivated to understand the behavior of implanted fluorine in silicon by experiments which suggest

Dunham, Scott

100

The role of technology and engineering models in transforming healthcare.  

PubMed

The healthcare system is in crisis due to challenges including escalating costs, the inconsistent provision of care, an aging population, and high burden of chronic disease related to health behaviors. Mitigating this crisis will require a major transformation of healthcare to be proactive, preventive, patient-centered, and evidence-based with a focus on improving quality-of-life. Information technology, networking, and biomedical engineering are likely to be essential in making this transformation possible with the help of advances, such as sensor technology, mobile computing, machine learning, etc. This paper has three themes: 1) motivation for a transformation of healthcare; 2) description of how information technology and engineering can support this transformation with the help of computational models; and 3) a technical overview of several research areas that illustrate the need for mathematical modeling approaches, ranging from sparse sampling to behavioral phenotyping and early detection. A key tenet of this paper concerns complementing prior work on patient-specific modeling and simulation by modeling neuropsychological, behavioral, and social phenomena. The resulting models, in combination with frequent or continuous measurements, are likely to be key components of health interventions to enhance health and wellbeing and the provision of healthcare. PMID:23549108

Pavel, Misha; Jimison, Holly Brugge; Wactlar, Howard D; Hayes, Tamara L; Barkis, Will; Skapik, Julia; Kaye, Jeffrey

2013-01-01

101

The WSU Model for Engineering Mathematics Education  

NSDL National Science Digital Library

The traditional approach to engineering mathematics education begins with one year of freshman calculus as a prerequisite to subsequent core engineering courses. However, the inability of incoming students to successfully advance through the traditional freshman calculus sequence is a primary cause of attrition in engineering programs across the country. As a result, the WSU model seeks to redefine the way in which engineering mathematics is taught, with the goal of increasing student retention, motivation and success in engineering. The WSU approach begins with the development of a novel freshman-level engineering mathematics course, EGR 101 Introductory Mathematics for Engineering Applications. Taught by engineering faculty, the course includes lecture, laboratory and recitation components. Using an application-oriented, hands-on approach, the course addresses only the salient math topics actually used in core engineering courses. These include the traditional physics, engineering mechanics, electric circuits and computer programming sequences. The EGR 101 course replaces traditional math prerequisite requirements for the above core courses, so that students can advance in the engineering curriculum without having completed a traditional freshman calculus sequence. This has enabled a significant restructuring of the engineering curriculum, including the placement of formerly sophomore-level engineering courses within the freshman year. The WSU model concludes with the development of a revised engineering math sequence, taught by the math department later in the curriculum, in concert with College and ABET requirements. The result has shifted the traditional emphasis on math prerequisite requirements to an emphasis on engineering motivation for math, with a "just-in-time" structuring of the new math sequence. Key components included with this resource are a lab activity, classroom activity, case study, self-guided student work, quiz/test, example problems, simulation and graphics/video.MERC Reviewers comments: The instructor has spent considerable amount of time and effort to develop this course. I really commend the instructor for the innovativeness in using MATLAB for solving problems and relating to practical applications. I very highly recommend that this course be offered to bring about the role of mathematics in engineering education.

Klingbeil, Nathan W.

102

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

103

Reverse engineering the structural and acoustic behavior of a stradivari violin  

NASA Astrophysics Data System (ADS)

There is a tremendous amount of mystery that surrounds the instruments of Antonio Stradivari. There have been many studies done in the past, but no one completely understands exactly how he made his instruments, or why they are still considered the best in the world. This project is designed to develop an engineering model of one of Stradivari's violins that will accurately simulate the structural and acoustic behavior of the instrument. It also hopes to shine some light on what makes the instruments of Stradivari unique when compared to other violins. It will focus on geometry and material properties, utilizing several modern engineering tools, including CT scanning, experimental modal analysis, finite element analysis, correlation techniques, and acoustic synthesis.

Pyrkosz, Michael

104

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

105

Combustion modeling in internal combustion engines  

NASA Technical Reports Server (NTRS)

The fundamental assumptions of the Blizard and Keck combustion model for internal combustion engines are examined and a generalization of that model is derived. The most significant feature of the model is that it permits the occurrence of unburned hydrocarbons in the thermodynamic-kinetic modeling of exhaust gases. The general formulas are evaluated in two specific cases that are likely to be significant in the applications of the model.

Zeleznik, F. J.

1976-01-01

106

Modeling shock loading behavior of concrete  

Microsoft Academic Search

In order to tackle behavior of individual components in concrete cells under shock loading, a multi-part model for concrete is presented, wherein mortar and aggregate are assumed to be in mechanical equilibrium and compressed or released isentropically. Computational simulations of plate shock experiments using the multi-part model for concrete are performed. Computational velocity histories of the free surface of the

Danian Chen; S. T. S Al-Hassani; Zhihua Yin; Yuying Yu

2001-01-01

107

A Dynamic Programming Model of Retirement Behavior  

Microsoft Academic Search

This paper formulates a model of retirement behavior based on the solution to a stochastic dynamic programming problem. The workers objective is to maximize expected discounted utility over his remaining lifetime. At each time period the worker chooses how much to consume and whether to work full-time, part-time, or exit the labor force. The model accounts for the sequential nature

John Rust

1987-01-01

108

Reusable Rocket Engine Operability Modeling and Analysis  

NASA Technical Reports Server (NTRS)

This paper describes the methodology, model, input data, and analysis results of a reusable launch vehicle engine operability study conducted with the goal of supporting design from an operations perspective. Paralleling performance analyses in schedule and method, this requires the use of metrics in a validated operations model useful for design, sensitivity, and trade studies. Operations analysis in this view is one of several design functions. An operations concept was developed given an engine concept and the predicted operations and maintenance processes incorporated into simulation models. Historical operations data at a level of detail suitable to model objectives were collected, analyzed, and formatted for use with the models, the simulations were run, and results collected and presented. The input data used included scheduled and unscheduled timeline and resource information collected into a Space Transportation System (STS) Space Shuttle Main Engine (SSME) historical launch operations database. Results reflect upon the importance not only of reliable hardware but upon operations and corrective maintenance process improvements.

Christenson, R. L.; Komar, D. R.

1998-01-01

109

Learning to Model in Engineering  

ERIC Educational Resources Information Center

Policymakers and education scholars recommend incorporating mathematical modeling into mathematics education. Limited implementation of modeling instruction in schools, however, has constrained research on how students learn to model, leaving unresolved debates about whether modeling should be reified and explicitly taught as a competence, whether…

Gainsburg, Julie

2013-01-01

110

Animal Models for Adipose Tissue Engineering  

PubMed Central

Abstract There is a critical need for adequate reconstruction of soft tissue defects resulting from tumor resection, trauma, and congenital abnormalities. To be sure, adipose tissue engineering strategies offer promising solutions. However, before clinical translation can occur, efficacy must be proven in animal studies. The aim of this review is to provide an overview of animal models currently employed for adipose tissue engineering. PMID:18544014

Uthamanthil, Rajesh; Beahm, Elisabeth; Frye, Cindy

2008-01-01

111

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

112

Modelling of genetically engineered microorganisms introduction in closed artificial microcosms.  

PubMed

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. PMID:11542542

Pechurkin, N S; Brilkov, A V; Ganusov, V V; Kargatova, T V; Maksimova, E E; Popova LYu

1999-01-01

113

Reflective Model Driven Engineering Jean Bezivin1  

E-print Network

the OMG initiative on Model Driven Architecture (MDA) [19]. In the air traffic management domain in its know-how of the business domain (the PIM) but also in the design know-how needed to makeReflective Model Driven Engineering Jean B´ezivin1 , Nicolas Farcet2 , Jean-Marc J´ez´equel3 , Beno

Paris-Sud XI, Université de

114

Software Engineering Tools for Scientific Models  

NASA Technical Reports Server (NTRS)

Software tools were constructed to address issues the NASA Fortran development community faces, and they were tested on real models currently in use at NASA. These proof-of-concept tools address the High-End Computing Program and the Modeling, Analysis, and Prediction Program. Two examples are the NASA Goddard Earth Observing System Model, Version 5 (GEOS-5) atmospheric model in Cell Fortran on the Cell Broadband Engine, and the Goddard Institute for Space Studies (GISS) coupled atmosphere- ocean model called ModelE, written in fixed format Fortran.

Abrams, Marc; Saboo, Pallabi; Sonsini, Mike

2013-01-01

115

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

116

Behavioral circuit modeling using neural networks  

NASA Astrophysics Data System (ADS)

A technique is presented for automatic generation of Analog Behavioral circuit models using feed-forward neural networks in static and dynamic configurations. These models are generated, by using the data output from an accurate SPICE simulation to train a neural network to model a particular circuit function. Results are given using two types of neural networks, a static neural network to model an analog multiplier, and a recurrent neural network for modeling the dynamics of a bandlimited circuit. Simulations show that neural networks are able to learn the essential nonlinear and dynamic properties found in these circuits using the training technique described.

Kosonocky, Stephen V.

1994-02-01

117

A Crowd Modeling Framework for Socially Plausible Animation Behaviors  

E-print Network

A Crowd Modeling Framework for Socially Plausible Animation Behaviors Seung In Park, Chao Peng behaviors. Our high-level behav- ioral model is able to produce appropriate animated behavior that in to CG theory, and macro-behavior relating to the animation context. This allows reuse of the micro-behaviors

Cao, Yong

118

Modeling student success in engineering education  

NASA Astrophysics Data System (ADS)

In order for the United States to maintain its global competitiveness, the long-term success of our engineering students in specific courses, programs, and colleges is now, more than ever, an extremely high priority. Numerous studies have focused on factors that impact student success, namely academic performance, retention, and/or graduation. However, there are only a limited number of works that have systematically developed models to investigate important factors and to predict student success in engineering. Therefore, this research presents three separate but highly connected investigations to address this gap. The first investigation involves explaining and predicting engineering students' success in Calculus I courses using statistical models. The participants were more than 4000 first-year engineering students (cohort years 2004 - 2008) who enrolled in Calculus I courses during the first semester in a large Midwestern university. Predictions from statistical models were proposed to be used to place engineering students into calculus courses. The success rates were improved by 12% in Calculus IA using predictions from models developed over traditional placement method. The results showed that these statistical models provided a more accurate calculus placement method than traditional placement methods and help improve success rates in those courses. In the second investigation, multi-outcome and single-outcome neural network models were designed to understand and to predict first-year retention and first-year GPA of engineering students. The participants were more than 3000 first year engineering students (cohort years 2004 - 2005) enrolled in a large Midwestern university. The independent variables include both high school academic performance factors and affective factors measured prior to entry. The prediction performances of the multi-outcome and single-outcome models were comparable. The ability to predict cumulative GPA at the end of an engineering student's first year of college was about a half of a grade point for both models. The predictors of retention and cumulative GPA while being similar differ in that high school academic metrics play a more important role in predicting cumulative GPA with the affective measures playing a more important role in predicting retention. In the last investigation, multi-outcome neural network models were used to understand and to predict engineering students' retention, GPA, and graduation from entry to departure. The participants were more than 4000 engineering students (cohort years 2004 - 2006) enrolled in a large Midwestern university. Different patterns of important predictors were identified for GPA, retention, and graduation. Overall, this research explores the feasibility of using modeling to enhance a student's educational experience in engineering. Student success modeling was used to identify the most important cognitive and affective predictors for a student's first calculus course retention, GPA, and graduation. The results suggest that the statistical modeling methods have great potential to assist decision making and help ensure student success in engineering education.

Jin, Qu

119

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

120

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

121

DEVS for Human Behavior Modeling in CGFs  

Microsoft Academic Search

In recent years, human behavior simulation has been an active field of research, and various approaches have been used. One of the main challenges is to design models that capture more of the subtleties of human nature to reach a higher level of realism. In this paper, we present the premises of a DEVS (Discrete Event System Specification) based framework

Mamadou Seck; Norbert Giambiasi; Claudia Frydman; Lassaad Baati

2007-01-01

122

Perceptual Modeling for Behavioral Animation of Fishes  

E-print Network

and their motions had to be laboriously keyframed like animated cartoons. Subsequently, researchers developedPerceptual Modeling for Behavioral Animation of Fishes Xiaoyuan Tu Demetri Terzopoulos Department of Computer Science University of Toronto, Toronto, Ontario, Canada, M5S 1A4 ABSTRACT The realistic animation

Toronto, University of

123

Testing Expectancy Theory Predictions Using Behaviorally Based Measures of Motivational Effort for Engineers  

ERIC Educational Resources Information Center

Expectancy theory predictions were tested using a sample of engineers who had been rated on dimensions of work motivation or effort (in contrast to performance) using the behaviorally based rating scales designed by Landy and Guion (1970). (Author)

Arvey, Richard D.; Neel, C. Warren

1974-01-01

124

A high fidelity starter model for engine start simulations  

Microsoft Academic Search

Engine start is a very crucial phase in the operation of automotive engines, and the starter motor plays a vital role in this short transient period. However, a complete and exhaustive model of the combined engine-starter system has not appeared to date in the open literature. Although many researchers have modeled the starter system in engine models, the role of

Qi Ma; Sai S V Rajagopalan; Stephen Yurkovich; Yann G Guezennec

2005-01-01

125

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

126

TISSUE ENGINEERING PERFUSABLE CANCER MODELS  

PubMed Central

The effect of fluid flow on cancer progression is currently not well understood, highlighting the need for perfused tumor models to close this gap in knowledge. Enabling biological processes at the cellular level to be modeled with high spatiotemporal control, microfluidic tumor models have demonstrated applicability as platforms to study cell-cell interactions, effect of interstitial flow on tumor migration and the role of vascular barrier function. To account for the multi-scale nature of cancer growth and invasion, macroscale models are also necessary. The consideration of fluid dynamics within tumor models at both the micro- and macroscopic levels may greatly improve our ability to more fully mimic the tumor microenvironment. PMID:24634812

Fong, E.L.; Santoro, M.; Farach-Carson, M.C.; Kasper, F.K.; Mikos, A.G.

2014-01-01

127

Turnaround Time Modeling for Conceptual Rocket Engines  

NASA Technical Reports Server (NTRS)

Recent years have brought about a paradigm shift within NASA and the Space Launch Community regarding the performance of conceptual design. Reliability, maintainability, supportability, and operability are no longer effects of design; they have moved to the forefront and are affecting design. A primary focus of this shift has been a planned decrease in vehicle turnaround time. Potentials for instituting this decrease include attacking the issues of removing, refurbishing, and replacing the engines after each flight. less, it is important to understand the operational affects of an engine on turnaround time, ground support personnel and equipment. One tool for visualizing this relationship involves the creation of a Discrete Event Simulation (DES). A DES model can be used to run a series of trade studies to determine if the engine is meeting its requirements, and, if not, what can be altered to bring it into compliance. Using DES, it is possible to look at the ways in which labor requirements, parallel maintenance versus serial maintenance, and maintenance scheduling affect the overall turnaround time. A detailed DES model of the Space Shuttle Main Engines (SSME) has been developed. Trades may be performed using the SSME Processing Model to see where maintenance bottlenecks occur, what the benefits (if any) are of increasing the numbers of personnel, or the number and location of facilities, in addition to trades previously mentioned, all with the goal of optimizing the operational turnaround time and minimizing operational cost. The SSME Processing Model was developed in such a way that it can easily be used as a foundation for developing DES models of other operational or developmental reusable engines. Performing a DES on a developmental engine during the conceptual phase makes it easier to affect the design and make changes to bring about a decrease in turnaround time and costs.

Nix, Michael; Staton, Eric J.

2004-01-01

128

SSME model, engine dynamic characteristics related to Pogo  

NASA Technical Reports Server (NTRS)

A linear model of the space shuttle main engine for use in Pogo studies was presented. A digital program is included from which engine transfer functions are determined relative to the engine operating level.

1973-01-01

129

Environmental Modeling of Mars: Thermal Behavior  

NASA Astrophysics Data System (ADS)

There is increasing demand for modeling of the Martian physical environment both for scientific studies and for design and operation of Mars missions. A variety of resources are available to meet these needs; most are the products of individual research efforts, and one - Mars-GRAM - is a parameterization model specifically intended for engineering applications. There is often a gap of understanding between the scientists and engineers that must be carefully addressed in order to portray accuracy of data, reliability of models, and applicability. At JPL we are collecting the most relevant scientific results and providing them to engineering staff in order to carry out a variety of studies. Among these are estimation of minimum nighttime 1-m air temperatures at the Mars Exploration Rover landing sites, in order to predict thermal losses that could limit mission lifetime; evaluation of the thermal flux on MRO instruments and radiative coolers; bounding atmospheric dust opacities for balloon operations; and wind modeling for evaluation of landing risk at potential MER sites. For MER, we combined thermal models validated by MGS TES data with a 1-D boundary layer model developed for Mars Pathfinder meteorology data modeling, to produce temperatures at 1 meter at 0600 hrs near the mission endpoints, to estimate whether certain landing sites would produce excessive cooling, and thus battery drain. Low thermal inertias at the Sinus Meridiani site produce temperatures that are problematical for a small fraction of the original landing ellipse. Data have generously been provided by MGS TES and Odyssey THEMIS team members, as well as mesoscale and boundary layer modelers. This research was carried out by the Jet Propulsion Laboratory, California Institute of Technology.

Martin, T. Z.; Bridges, N. T.; Murphy, J. R.

2003-05-01

130

Tissue-engineered kidney disease models.  

PubMed

Renal disease represents a major health problem that often results in end-stage renal failure necessitating dialysis and eventually transplantation. Historically these diseases have been studied with patient observation and screening, animal models, and two-dimensional cell culture. In this review, we focus on recent advances in tissue engineered kidney disease models that have the capacity to compensate for the limitations of traditional modalities. The cells and materials utilized to develop these models are discussed and tissue engineered models of polycystic kidney disease, drug-induced nephrotoxicity, and the glomerulus are examined in detail. The application of these models has the potential to direct future disease treatments and preclinical drug development. PMID:24361391

Desrochers, Teresa M; Palma, Erica; Kaplan, David L

2014-04-01

131

Prerequisites: Control Systems I+II, System Modeling, Engine Class (Introduction to Modeling and Control of  

E-print Network

Thesis IDSC-LG-FZ-05 Gas Diesel Engine Modeling and Control The gas diesel engine is a natural gas enginePrerequisites: Control Systems I+II, System Modeling, Engine Class (Introduction to Modeling and Control of Internal Combustion Engine Systems, IC Engines, ...), Optimization Course, Matlab

Lygeros, John

132

Cheating in College and the Workplace: An Examination of Engineering Undergraduates' Ethical Behavior  

Microsoft Academic Search

Research has demonstrated that engineering undergraduates report higher rates of cheating than those in other disciplines and that students who cheat in college are more likely to make unethical decisions as professionals. Therefore, better understanding the decision-making processes of engineering students and professionals who engage in dishonest behavior could lead to effective college-level interventions to cheating that have a positive

Trevor S. Harding; Donald D. Carpenter; Cynthia J. Finelli

2005-01-01

133

Investigating Breast Cancer Cell Behavior Using Tissue Engineering Scaffolds  

PubMed Central

Despite early detection through the use of mammograms and aggressive intervention, breast cancer (BC) remains a clinical dilemma. BC can resurge after >10 years of remission. Studies indicate that BC cells (BCCs) with self-renewal and chemoresistance could be involved in dormancy. The majority of studies use in vitro, two-dimensional (2-D) monolayer cultures, which do not recapitulate the in vivo microenvironment. Thus, to determine the effect of three-dimensional (3-D) microenvironment on BCCs, this study fabricated tissue engineering scaffolds made of poly (?-caprolactone) (PCL) having aligned or random fibers. Random and aligned fibers mimic, respectively, the random and highly organized collagen fibers found in the tumor extracellular matrix. Chemoresistant BCCs were obtained by treating with carboplatin. Western blot analysis of carboplatin resistant (treated) MDA-MB-231 (highly invasive, basal-like) and T47D (low-invasive, luminal) BCCs showed an increase in Bcl-2, Oct-4 and Sox-2, suggesting protection from apoptosis and increase in stem-like markers. Further studies with MDA-MB-231 BCCs seeded on the scaffolds showed little to no change in cell number over time for non-treated BCCs whereas on tissue culture polystyrene (TCP), non-treated BCCs displayed a significant increase in cell number at days 4 and 7 as compared to day 1 (p<0.05). Treated BCCs did not proliferate on TCP and the fibrous scaffolds. Little to no cyclin D1 was expressed for non-treated BCCs on TCP. On fibrous scaffolds, non-treated BCCs stained for cyclin D1 during the 7-day culture period. Treated BCCs expressed cyclin D1 on TCP and fibrous scaffolds during the 7-day culture period. Proliferation, viability and cell cycle analysis indicated that this 3-D culture prompted the aggressive BCCs to adopt a dormant phenotype, while the treated BCCs retained their phenotype. The findings indicate that random and aligned fibrous PCL scaffolds may provide a useful system to study how the 3-D microenvironment affects the behavior of BCCs. PMID:25837691

Guiro, Khadidiatou; Patel, Shyam A.; Greco, Steven J.; Rameshwar, Pranela; Arinzeh, Treena L.

2015-01-01

134

Modeling irrigation behavior in groundwater systems  

NASA Astrophysics Data System (ADS)

Integrated hydro-economic models have been widely applied to water management problems in regions of intensive groundwater-fed irrigation. However, policy interpretations may be limited as most existing models do not explicitly consider two important aspects of observed irrigation decision making, namely the limits on instantaneous irrigation rates imposed by well yield and the intraseasonal structure of irrigation planning. We develop a new modeling approach for determining irrigation demand that is based on observed farmer behavior and captures the impacts on production and water use of both well yield and climate. Through a case study of irrigated corn production in the Texas High Plains region of the United States we predict optimal irrigation strategies under variable levels of groundwater supply, and assess the limits of existing models for predicting land and groundwater use decisions by farmers. Our results show that irrigation behavior exhibits complex nonlinear responses to changes in groundwater availability. Declining well yields induce large reductions in the optimal size of irrigated area and irrigation use as constraints on instantaneous application rates limit the ability to maintain sufficient soil moisture to avoid negative impacts on crop yield. We demonstrate that this important behavioral response to limited groundwater availability is not captured by existing modeling approaches, which therefore may be unreliable predictors of irrigation demand, agricultural profitability, and resilience to climate change and aquifer depletion.

Foster, Timothy; Brozovi?, Nicholas; Butler, Adrian P.

2014-08-01

135

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

136

1106 / JOURNAL OF ENGINEERING MECHANICS / NOVEMBER 2001 DRAINED CYCLIC BEHAVIOR OF SAND WITH FABRIC DEPENDENCE  

E-print Network

1106 / JOURNAL OF ENGINEERING MECHANICS / NOVEMBER 2001 DRAINED CYCLIC BEHAVIOR OF SAND WITH FABRIC DEPENDENCE By Richard G. Wan1 and Pei J. Guo2 ABSTRACT: The behavior of sand is characterized by dilatancy, an increase in overall volume as particles move over each other when the sand assembly is subjected to shear

Wan, Richard G.

137

Combustion engine modelling using an evolving local model network  

Microsoft Academic Search

In this paper a new evolving parameter estimation algorithm for a local model network under special consideration of combustion engine modelling is presented. For practical appli- cations computational speed, incorporation of prior knowledge and the interpretability of the local models is of great interest. Accordingly, a robust and efficient online training algorithm with a particular focus on computational requirements involved

Christoph Hametner; Stefan Jakubek

2011-01-01

138

Electrocoalescence modeling: an engineering approach  

Microsoft Academic Search

In a stagnant water-in-oil emulsion subjected to an external AC electrical field, charges induced on the water drops will cau se adjacent drops to attract each other. Simulations and exper- imental observations are here compared. A discrete particle model of the emulsion is implemented and used to calculate the two-dimensional motion of the individual, spherical water drops directly from the

M. Chiesa

139

Space shuttle main engine plume radiation model  

NASA Technical Reports Server (NTRS)

The methods are described which are used in predicting the thermal radiation received by space shuttles, from the plumes of the main engines. Radiation to representative surface locations were predicted using the NASA gaseous plume radiation GASRAD program. The plume model is used with the radiative view factor (RAVFAC) program to predict sea level radiation at specified body points. The GASRAD program is described along with the predictions. The RAVFAC model is also discussed.

Reardon, J. E.; Lee, Y. C.

1978-01-01

140

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

141

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

142

Approximate simulation model for analysis and optimization in engineering system design  

NASA Technical Reports Server (NTRS)

Computational support of the engineering design process routinely requires mathematical models of behavior to inform designers of the system response to external stimuli. However, designers also need to know the effect of the changes in design variable values on the system behavior. For large engineering systems, the conventional way of evaluating these effects by repetitive simulation of behavior for perturbed variables is impractical because of excessive cost and inadequate accuracy. An alternative is described based on recently developed system sensitivity analysis that is combined with extrapolation to form a model of design. This design model is complementary to the model of behavior and capable of direct simulation of the effects of design variable changes.

Sobieszczanski-Sobieski, Jaroslaw

1989-01-01

143

Privacy Engineering Objectives and Risk Model-Discussion Deck  

E-print Network

, Confidentiality) Metrics ModelPrivacy Risk Management Framework Privacy Engineering Components Policy (LawPrivacy Engineering Objectives and Risk Model- Discussion Deck Objective-Based Design for Improving components of privacy engineering developed from the output of NIST's first Privacy Engineering Workshop

144

Transient behavior in the Lorenz model  

NASA Astrophysics Data System (ADS)

Dynamical systems like the one described by the three-variable Lorenz model may serve as metaphors for complexity in nature. When natural systems are perturbed by external forcing factors, they tend to relax back to their equilibrium conditions after the forcing has shut off. Here we investigate the behavior of such transients in the Lorenz model by studying its trajectories initialized far away from the asymptotic attractor. Perhaps somewhat surprisingly, these transient trajectories exhibit complex routes and, among other things, sensitivity to initial conditions akin to that of the asymptotic behavior on the attractor. Thus, similar extreme events may lead to widely different variations before the perturbed system returns back to its statistical equilibrium.

Kravtsov, S.; Sugiyama, N.; Tsonis, A. A.

2014-12-01

145

Behavior model of mixed ADC systems  

Microsoft Academic Search

We propose a behavior-based macro-model of mixed ADC systems as a tool for high-level simulation, investigation and pilot testing, as well as a tool to facilitate and support a design process of other systems containing them. Our aim is to characterize the dynamic and nonlinear properties of ADC systems simultaneously with the representing of discrete nature of ADC output. To

A. Gertners; V. Zagursky; D. Z. Saldava

1996-01-01

146

Modeling, validation and system identification of a natural gas engine  

Microsoft Academic Search

In this paper, a model of a central fuel injected natural gas engine with transmission is developed and linear system identification is carried out to identify key model parameters that could lead to automated identification of transmission dynamics. The paper has two major components. First, the natural gas engine is modeled with an extension of the mean value engine model

Anupam Gangopadhyay; Peter Meckl

1997-01-01

147

Towards Understanding and Modeling Individual Behavior and Group Dynamics  

Microsoft Academic Search

Understanding human behavior is a very complex task. In this paper we present our initial thoughts on modeling and automatic recognition of human activities. We argue that to successfully model human behavior, we need to consider both individual behavior and group dynamics. To demonstrate these theoretical approaches, we also introduce two experimental systems for collecting experimental data of complex behaviors.

Michele Bezzi; Robin Groenevelt

148

Behavior modeling through CHAOS for simulation of dismounted soldier operations  

Microsoft Academic Search

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

Emiel Ubink; Frank Aldershoff; Wouter Lotens; Arend Woering

2008-01-01

149

Genome-scale modeling for metabolic engineering.  

PubMed

We focus on the application of constraint-based methodologies and, more specifically, flux balance analysis in the field of metabolic engineering, and enumerate recent developments and successes of the field. We also review computational frameworks that have been developed with the express purpose of automatically selecting optimal gene deletions for achieving improved production of a chemical of interest. The application of flux balance analysis methods in rational metabolic engineering requires a metabolic network reconstruction and a corresponding in silico metabolic model for the microorganism in question. For this reason, we additionally present a brief overview of automated reconstruction techniques. Finally, we emphasize the importance of integrating metabolic networks with regulatory information-an area which we expect will become increasingly important for metabolic engineering-and present recent developments in the field of metabolic and regulatory integration. PMID:25578304

Simeonidis, Evangelos; Price, Nathan D

2015-03-01

150

Animal Models of Compulsive Eating Behavior  

PubMed Central

Eating disorders are multifactorial conditions that can involve a combination of genetic, metabolic, environmental, and behavioral factors. Studies in humans and laboratory animals show that eating can also be regulated by factors unrelated to metabolic control. Several studies suggest a link between stress, access to highly palatable food, and eating disorders. Eating “comfort foods” in response to a negative emotional state, for example, suggests that some individuals overeat to self-medicate. Clinical data suggest that some individuals may develop addiction-like behaviors from consuming palatable foods. Based on this observation, “food addiction” has emerged as an area of intense scientific research. A growing body of evidence suggests that some aspects of food addiction, such as compulsive eating behavior, can be modeled in animals. Moreover, several areas of the brain, including various neurotransmitter systems, are involved in the reinforcement effects of both food and drugs, suggesting that natural and pharmacological stimuli activate similar neural systems. In addition, several recent studies have identified a putative connection between neural circuits activated in the seeking and intake of both palatable food and drugs. The development of well-characterized animal models will increase our understanding of the etiological factors of food addiction and will help identify the neural substrates involved in eating disorders such as compulsive overeating. Such models will facilitate the development and validation of targeted pharmacological therapies. PMID:25340369

Di Segni, Matteo; Patrono, Enrico; Patella, Loris; Puglisi-Allegra, Stefano; Ventura, Rossella

2014-01-01

151

Modeling microdamage behavior of cortical bone.  

PubMed

Bone is a complex material which exhibits several hierarchical levels of structural organization. At the submicron-scale, the local tissue porosity gives rise to discontinuities in the bone matrix which have been shown to influence damage behavior. Computational tools to model the damage behavior of bone at different length scales are mostly based on finite element (FE) analysis, with a range of algorithms developed for this purpose. Although the local mechanical behavior of bone tissue is influenced by microstructural features such as bone canals and osteocyte lacunae, they are often not considered in FE damage models due to the high computational cost required to simulate across several length scales, i.e., from the loads applied at the organ level down to the stresses and strains around bone canals and osteocyte lacunae. Hence, the aim of the current study was twofold: First, a multilevel FE framework was developed to compute, starting from the loads applied at the whole bone scale, the local mechanical forces acting at the micrometer and submicrometer level. Second, three simple microdamage simulation procedures based on element removal were developed and applied to bone samples at the submicrometer-scale, where cortical microporosity is included. The present microdamage algorithm produced a qualitatively analogous behavior to previous experimental tests based on stepwise mechanical compression combined with in situ synchrotron radiation computed tomography. Our results demonstrate the feasibility of simulating microdamage at a physiologically relevant scale using an image-based meshing technique and multilevel FE analysis; this allows relating microdamage behavior to intracortical bone microstructure. PMID:24622917

Donaldson, Finn; Ruffoni, Davide; Schneider, Philipp; Levchuk, Alina; Zwahlen, Alexander; Pankaj, Pankaj; Müller, Ralph

2014-11-01

152

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

153

Model based systems engineering for astronomical projects  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

154

SPECIAL ISSUE PAPER Modeling social behaviors in an evacuation simulator  

E-print Network

significantly impact egress performance. By simulating different occupants' behaviors, architects and facility Department of Civil and Environmental Engineering, Stanford University, Stanford, California, USA 4 Computer managers may better understand the influence of human and social factors on evacuation and consequently

Stanford University

155

Evolution of Reference: A New Service Model for Science and Engineering Libraries  

ERIC Educational Resources Information Center

This article explores the different steps involved in adopting a new service model at the University of Arizona Science-Engineering Library. In a time of shrinking budgets and changing user behavior the library was forced to rethink it reference services to be cost effective and provide quality service at the same time. The new model required…

Bracke, Marianne Stowell; Chinnaswamy, Sainath; Kline, Elizabeth

2008-01-01

156

730 / JOURNAL OF ENGINEERING MECHANICS / JULY 2001 SIMULATED MICROMECHANICAL MODELS USING ARTIFICIAL  

E-print Network

damage and mechanics of materials (Pecknold and Haj-Ali 1993; Haj-Ali and Pecknold 1996). The difficulty730 / JOURNAL OF ENGINEERING MECHANICS / JULY 2001 SIMULATED MICROMECHANICAL MODELS USING), is proposed to generate micromechanical material models for nonlinear and damage behavior of heterogeneous

Haj-Ali, Rami

157

Modeling deformation behavior of the baseball.  

PubMed

Regulating ball response to impact is one way to control ball exit velocity in baseball. This is necessary to reduce injuries to defensive players and maintain the balance between offense and defense in the game. This paper presents a model for baseball velocity-dependent behavior. Force-displacement data were obtained using quasi-static compression tests to 50% of ball diameter (n = 70 baseballs). The force-displacement curves for a very stiff baseball (Model B) and a softer type (Model C) were characterized by a Mooney-Rivlin model using implicit finite element analysis (ANSYS software, version 6.1). Agreement between experimental and numerical results was excellent for both Model B (C(10) = 0, C(01) = 3.7e(6) Pa) and Model C (C(10) = 0, C(01) = 2.6e(6) Pa). However, this material model was not available in the ANSYS/LSDYNA explicit dynamic software (version 6.1) used to quantify the transient behavior of the ball. Therefore the modeling process was begun again using a linear viscoelastic material. G(infinity), the long-term shear modulus of the material, was determined by the same implicit FEA procedure. Explicit FEA was used to quantify the time-dependent response of each ball in terms of instantaneous shear modulus (G0) and a decay term (beta). The results were evaluated with respect to published experimental data for the ball coefficient of restitution at five velocities (13.4-40.2 ms(-1)) and were in agreement with the experimental values. The model forms the basis for future research on baseball response to impact with the bat. PMID:16131702

Nicholls, Rochelle Llewelyn; Miller, Karol; Elliott, Bruce C

2005-02-01

158

The Internet as recommendation engine : implications of online behavioral targeting  

E-print Network

This thesis discusses the economic implications of Internet behavioral advertising, which targets ads to individuals based on extensive detailed data about the specific websites users have visited. Previous literature on ...

Smith-Grieco, Anthony Nicoll

2010-01-01

159

Engineering model for predicting rubble motion during blasting  

SciTech Connect

Recent applications of explosives and blasting agents to rubble rock have led to requirements for more elaborate design and analysis methods. In most blasting uses, it is necessary not only to fracture the rock, but also to move the broken rubble in a predictable manner. Many in-situ extraction techniques require rubblization to take place in a confined region where rock motion is a predominate factor in creating a permeable broken bed. In this paper, an engineering model is presented which describes the large rubble motion during blasting. This model is intended to provide the blast designer with a tool for evaluation and further refinement of blasting patterns and timing sequences. In this model the rock medium is represented by a discrete series of circular regions of fractured material. These regions are set in motion by pressure loads from the explosive. The motion of the regions is calculated using a step-wise, explicit, numerical time integration method. Interaction of adjacent regions is based on inelastic impact of spherical bodies. The derivation of this model is presented along with the background for selecting loading pressure based on explosive behavior. Three typical examples, including both cratering and bench geometries, are discussed which illustrate the use of this model to predict rubble motion. This engineering representation appears to provide a practical model for use in predicting rubble motion and a tool for design evaluation of blasting in confined geometries. 15 figures.

Schamaun, J.T.

1982-12-01

160

Engineering model for predicting rubble motion during blasting  

SciTech Connect

Recent applications of explosives and blasting agents to rubble rock have led to requirements for more elaborate design and analysis methods. In most blasting uses, it is necessary not only to fracture the rock, but also to move the broken rubble in a predictable manner. Many in situ extraction techniques require rubblization to take place in a confined region where rock motion is a predominate factor in creating a permeable broken bed. In this paper, an engineering model is presented which describes the large rubble motion during blasting. This model is intended to provide the blast designer with a tool for evaluation and further refinement of blasting patterns and timing sequences. In this model the rock medium is represented by a discrete series of circular regions of fractured material. These regions are set in motion by pressure loads from the explosive. The motion of the regions is calculated using a step-wise, explicit, numerical time integration method. Interaction of adjacent regions is based on inelastic impact of spherical bodies. The derivation of this model is presented along with the background for selecting loading pressure based on explosive behavior. Three typical examples, including both cratering and bench geometries, are discussed which illustrate the use of this model to predict rubble motion. This engineering representation appears to provide a practical model for use in predicting rubble motion and a tool for design evaluation of blasting in confined geometries. 15 figures, 1 table.

Schamaun, J.T.

1983-01-01

161

Genetically Engineered Mouse Models of Pituitary Tumors  

PubMed Central

Animal models constitute valuable tools for investigating the pathogenesis of cancer as well as for preclinical testing of novel therapeutics approaches. However, the pathogenic mechanisms of pituitary-tumor formation remain poorly understood, particularly in sporadic adenomas, thus, making it a challenge to model pituitary tumors in mice. Nevertheless, genetically engineered mouse models (GEMMs) of pituitary tumors have provided important insight into pituitary tumor biology. In this paper, we review various GEMMs of pituitary tumors, highlighting their contributions and limitations, and discuss opportunities for research in the field. PMID:25136513

Cano, David A.; Soto-Moreno, Alfonso; Leal-Cerro, Alfonso

2014-01-01

162

Software-Engineering Process Simulation (SEPS) model  

NASA Technical Reports Server (NTRS)

The Software Engineering Process Simulation (SEPS) model is described which was developed at JPL. SEPS is a dynamic simulation model of the software project development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life cycle development activities and management decision making processes. The model is designed to be a planning tool to examine tradeoffs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmodern assessments.

Lin, C. Y.; Abdel-Hamid, T.; Sherif, J. S.

1992-01-01

163

3D Modeling Engine Representation Summary Report  

SciTech Connect

Computers have been used for 3D modeling and simulation, but only recently have computational resources been able to give realistic results in a reasonable time frame for large complex models. This summary report addressed the methods, techniques, and resources used to develop a 3D modeling engine to represent risk analysis simulation for advanced small modular reactor structures and components. The simulations done for this evaluation were focused on external events, specifically tsunami floods, for a hypothetical nuclear power facility on a coastline.

Steven Prescott; Ramprasad Sampath; Curtis Smith; Timothy Yang

2014-09-01

164

Summary Report of the OOPSLA 2000 Workshop on Scenario-Based Round-Trip Engineering  

E-print Network

into three sessions: From Interaction Diagrams to State Machines, Forward Engineering, and Reverse-oriented (OO) software engineering. In modern OO modeling notations, behavioral modeling is supported on scenario specifications · using UML behavioral models for reverse engineering OO software systems

Keller, Rudolf K.

165

Cycle Engine Modelling Of Spark Ignition Engine Processes during Wide-Open Throttle (WOT) Engine Operation Running By Gasoline Fuel  

NASA Astrophysics Data System (ADS)

One-dimensional engine model is developed to simulate spark ignition engine processes in a 4-stroke, 4 cylinders gasoline engine. Physically, the baseline engine is inline cylinder engine with 3-valves per cylinder. Currently, the engine's mixture is formed by external mixture formation using piston-type carburettor. The model of the engine is based on one-dimensional equation of the gas exchange process, isentropic compression and expansion, progressive engine combustion process, and accounting for the heat transfer and frictional losses as well as the effect of valves overlapping. The model is tested for 2000, 3000 and 4000 rpm of engine speed and validated using experimental engine data. Results showed that the engine is able to simulate engine's combustion process and produce reasonable prediction. However, by comparing with experimental data, major discrepancy is noticeable especially on the 2000 and 4000 rpm prediction. At low and high engine speed, simulated cylinder pressures tend to under predict the measured data. Whereas the cylinder temperatures always tend to over predict the measured data at all engine speed. The most accurate prediction is obtained at medium engine speed of 3000 rpm. Appropriate wall heat transfer setup is vital for more precise calculation of cylinder pressure and temperature. More heat loss to the wall can lower cylinder temperature. On the hand, more heat converted to the useful work mean an increase in cylinder pressure. Thus, instead of wall heat transfer setup, the Wiebe combustion parameters are needed to be carefully evaluated for better results.

Rahim, M. F. Abdul; Rahman, M. M.; Bakar, R. A.

2012-09-01

166

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

167

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

168

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.

169

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

170

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

171

A simplified dynamic model of the T700 turboshaft engine  

NASA Technical Reports Server (NTRS)

A simplified open-loop dynamic model of the T700 turboshaft engine, valid within the normal operating range of the engine, is developed. This model is obtained by linking linear state space models obtained at different engine operating points. Each linear model is developed from a detailed nonlinear engine simulation using a multivariable system identification and realization method. The simplified model may be used with a model-based real time diagnostic scheme for fault detection and diagnostics, as well as for open loop engine dynamics studies and closed loop control analysis utilizing a user generated control law.

Duyar, Ahmet; Gu, Zhen; Litt, Jonathan S.

1992-01-01

172

Numerical modeling of the thermal behavior during the LENS ® process  

Microsoft Academic Search

Laser Engineered Net-Shaping (LENS®) is an emerging manufacturing technique that ensures significant reduction of process time between initial design and final components. The fabrication of fully dense parts with appropriate properties using the LENS® process requires an in-depth understanding of the entire thermal behavior of the process. In this paper, the thermal behavior during LENS® was studied, both numerically and

Riqing Ye; John E. Smugeresky; Baolong Zheng; Yizhang Zhou; Enrique J. Lavernia

2006-01-01

173

Damage Propagation Modeling for Aircraft Engine Prognostics  

NASA Technical Reports Server (NTRS)

This paper describes how damage propagation can be modeled within the modules of aircraft gas turbine engines. To that end, response surfaces of all sensors are generated via a thermo-dynamical simulation model for the engine as a function of variations of flow and efficiency of the modules of interest. An exponential rate of change for flow and efficiency loss was imposed for each data set, starting at a randomly chosen initial deterioration set point. The rate of change of the flow and efficiency denotes an otherwise unspecified fault with increasingly worsening effect. The rates of change of the faults were constrained to an upper threshold but were otherwise chosen randomly. Damage propagation was allowed to continue until a failure criterion was reached. A health index was defined as the minimum of several superimposed operational margins at any given time instant and the failure criterion is reached when health index reaches zero. Output of the model was the time series (cycles) of sensed measurements typically available from aircraft gas turbine engines. The data generated were used as challenge data for the Prognostics and Health Management (PHM) data competition at PHM 08.

Saxena, Abhinav; Goebel, Kai; Simon, Don; Eklund, Neil

2008-01-01

174

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

175

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. PMID:19073222

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

2009-01-01

176

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

177

Dynamics of macroautophagy: Modeling and oscillatory behavior  

NASA Astrophysics Data System (ADS)

We propose a model for macroautophagy and study the resulting dynamics of autophagy in a system isolated from its extra-cellular environment. It is found that the intracellular concentrations of autophagosomes and autolysosomes display oscillations with their own natural frequencies. Such oscillatory behaviors, which are interrelated to the dynamics of intracellular ATP, amino acids, and proteins, are consistent with the very recent biological observations. Implications of this theoretical study of autophagy are discussed, with regard to the possibility of guiding molecular studies of autophagy.

Han, Kyungreem; Kwon, Hyun Woong; Kang, Hyuk; Kim, Jinwoong; Lee, Myung-Shik; Choi, M. Y.

2012-02-01

178

Modeling Pseudo-elastic Behavior of Springback  

SciTech Connect

One of the principal foundations of mathematical theory of conventional plasticity for rate-independent metals is that there exists a well-defined yield surface in stress space for any material point under deformation. A material point can undergo further plastic deformation if the applied stresses are beyond current yield surface which is generally referred as 'plastic loading'. On the other hand, if the applied stress state falls within or on the yield surface, the metal will deform elastically only and is said to be undergoing 'elastic unloading'. Although it has been always recognized throughout the history of development of plasticity theory that there is indeed inelastic deformation accompanying elastic unloading, which leads to metal's hysteresis behavior, its effects were thought to be negligible and were largely ignored in the mathematical treatment.Recently there have been renewed interests in the study of unloading behavior of sheet metals upon large plastic deformation and its implications on springback prediction. Springback is essentially an elastic recovery process of a formed sheet metal blank when it is released from the forming dies. Its magnitude depends on the stress states and compliances of the deformed sheet metal if no further plastic loading occurs during the relaxation process. Therefore the accurate determination of material compliances during springback and its effective incorporation into simulation software are important aspects for springback calculation. Some of the studies suggest that the unloading curve might deviate from linearity, and suggestions were made that a reduced elastic modulus be used for springback simulation.The aim of this study is NOT to take a position on the debate of whether elastic moduli are changed during sheet metal forming process. Instead we propose an approach of modeling observed psuedoelastic behavior within the context of mathematical theory of plasticity, where elastic moduli are treated to be constant. In the context of this investigation we refer psuedoelastic behavior in the most general sense as any deviation from linearity in the unloading curve. The non-linearity leads to a hysteresis loop upon reloading. The approach is based on the non-conventional theory with a vanishing elastic region as advanced by Dafalias and Popov. The treatment is purely phenomenological where we don't distinguish between macroscopic plasticity and micro-plasticity. The macroscopic uniaxial stress-strain curve is used to define effective plastic response in the same manner as classical plasticity theory except that the nonlinearity during unloading and reloading are incorporated into plasticity. It is shown that such models can be easily formulated within the context of elastoplasticity without violating any physical mechanisms of deformation. Springback for a plane strain bending model is used to demonstrate the potential effect if such a model is applied.

Xia, Z. Cedric [Scientific Research Laboratories, Ford Motor Company, Dearborn, MI 48121 (United States)

2005-08-05

179

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

180

An emotion-centered model of voluntary work behavior  

Microsoft Academic Search

We present a model that integrates findings from several areas to explain in parallel the voluntary acts of counterproductive work behavior (CWB) and organizational citizenship behavior (OCB). CWB is behavior, such as aggression or sabotage, intended to hurt the organization or its employees. OCB is prosocial behavior intended to help. A variety of job\\/organizational conditions (constraints on performance, job stressors,

Paul E Spector; Suzy Fox

2002-01-01

181

A model of wine tourist behavior: A festival approach  

Microsoft Academic Search

The study constructs a temporal model of wine tourist behavior on the basis of the social psychologist' theory of consumer attitudes and related concepts with regard to past behavior, satisfaction, perceived value, and behavioral intentions. This study proposed that wine festival attendees' intentions to revisit the festival would be affected by their satisfaction with, perceived value of, and past behavior

Jingxue Yuan

2004-01-01

182

Protein engineering and the use of molecular modeling and simulation: the case of heterodimeric Fc engineering.  

PubMed

Computational and structure guided methods can make significant contributions to the development of solutions for difficult protein engineering problems, including the optimization of next generation of engineered antibodies. In this paper, we describe a contemporary industrial antibody engineering program, based on hypothesis-driven in silico protein optimization method. The foundational concepts and methods of computational protein engineering are discussed, and an example of a computational modeling and structure-guided protein engineering workflow is provided for the design of best-in-class heterodimeric Fc with high purity and favorable biophysical properties. We present the engineering rationale as well as structural and functional characterization data on these engineered designs. PMID:24211748

Spreter Von Kreudenstein, Thomas; Lario, Paula I; Dixit, Surjit B

2014-01-01

183

Modeling the effect of engine assembly mass on engine friction and vehicle fuel economy  

SciTech Connect

In this paper, an analytical model is developed to estimate the impact of reducing engine assembly mass (the term engine assembly refers to the moving components of the engine system, including crankshafts, valve train, pistons, and connecting rods) on engine friction and vehicle fuel economy. The relative changes in frictional mean effective pressure and fuel economy are proportional to the relative change in assembly mass. These changes increase rapidly as engine speed increases. Based on the model, a 25% reduction in engine assembly mass results in a 2% fuel economy improvement for a typical mid-size passenger car over the EPA Urban and Highway Driving Cycles.

An, Feng [University of California, Riverside, CA (United States); Stodolsky, F. [Argonne National Lab., IL (United States)

1995-06-01

184

Unified constitutive model for single crystal deformation behavior with applications  

NASA Technical Reports Server (NTRS)

Single crystal materials are being used in gas turbine airfoils and are candidates for other hot section components because of their increased temperature capabilities and resistance to thermal fatigue. Development of a constitutive model which assesses the inelastic behavior of these materials has been studied in 2 NASA programs: Life Prediction and Constitutive Models for Engine Hot Section Anisotropic Materials and Biaxial Constitutive Equation Development for Single Crystals. The model has been fit to a large body of constitutive data for single crystal PWA 1480 material. The model uses a unified approach for computing total inelastic strains (creep plus plasticity) on crystallographic slip systems reproducing observed directional and strain rate effects as a natural consequence of the summed slip system quantities. The model includes several of the effects that have been reported to influence deformation in single crystal materials, such as shear stress, latent hardening, and cross slip. The model is operational in a commercial Finite Element code and is being installed in a Boundary Element Method code.

Walker, K. P.; Meyer, T. G.; Jordan, E. H.

1988-01-01

185

Energy Efficient Engine Exhaust Mixer Model Technology  

NASA Technical Reports Server (NTRS)

An exhaust mixer test program was conducted to define the technology required for the Energy Efficient Engine Program. The model configurations of 1/10 scale were tested in two phases. A parametric study of mixer design options, the impact of residual low pressure turbine swirl, and integration of the mixer with the structural pylon of the nacelle were investigated. The improvement of the mixer itself was also studied. Nozzle performance characteristics were obtained along with exit profiles and oil smear photographs. The sensitivity of nozzle performance to tailpipe length, lobe number, mixer penetration, and mixer modifications like scalloping and cutbacks were established. Residual turbine swirl was found detrimental to exhaust system performance and the low pressure turbine system for Energy Efficient Engine was designed so that no swirl would enter the mixer. The impact of mixer/plug gap was also established, along with importance of scalloping, cutbacks, hoods, and plug angles on high penetration mixers.

Kozlowski, H.; Larkin, M.

1981-01-01

186

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

187

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

188

Modeling Score Distributions for Combining the Outputs of Search Engines  

E-print Network

Modeling Score Distributions for Combining the Outputs of Search Engines R. Manmatha, T. Rath and F fits TREC-3 and TREC-4 data for not only probabilistic search engines like INQUERY but also vector space search engines like SMART for English. We have also used this model to fit the output of other

Massachusetts at Amherst, University of

189

Prerequisites: Control Systems I+II, System Modeling, Engine Class (Introduction to Modeling and Control of  

E-print Network

and Control of Internal Combustion Engine Systems, IC Engines, ...), Matlab/Simulink experience Contact and Control The gas-diesel engine is a natural gas engine, where the combustion is initiated by a smallPrerequisites: Control Systems I+II, System Modeling, Engine Class (Introduction to Modeling

Daraio, Chiara

190

Cognitive and Behavioral Model Ensembles for Autonomous Virtual Characters  

E-print Network

University, Provo Utah, USA February 24, 2010 Abstract Cognitive and behavioral models have become popularCognitive and Behavioral Model Ensembles for Autonomous Virtual Characters Jeffrey S. Whiting and in the creation of new behaviors and anima- tions. This paper provides a framework that can aggregate existing

Martinez, Tony R.

191

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

192

Effect of Surface Impulsive Thermal Loads on Fatigue Behavior of Constant Volume Propulsion Engine Combustor Materials  

NASA Technical Reports Server (NTRS)

The development of advanced high performance constant-volume-combustion-cycle engines (CVCCE) requires robust design of the engine components that are capable of enduring harsh combustion environments under high frequency thermal and mechanical fatigue conditions. In this study, a simulated engine test rig has been established to evaluate thermal fatigue behavior of a candidate engine combustor material, Haynes 188, under superimposed CO2 laser surface impulsive thermal loads (30 to 100 Hz) in conjunction with the mechanical fatigue loads (10 Hz). The mechanical high cycle fatigue (HCF) testing of some laser pre-exposed specimens has also been conducted under a frequency of 100 Hz to determine the laser surface damage effect. The test results have indicated that material surface oxidation and creep-enhanced fatigue is an important mechanism for the surface crack initiation and propagation under the simulated CVCCE engine conditions.

Zhu, Dongming; Fox, Dennis S.; Miller, Robert A.; Ghosn, Louis J.; Kalluri, Sreeramesh

2004-01-01

193

Kinetic modelling of a surrogate diesel fuel applied to 3D auto-ignition in HCCI engines  

E-print Network

The prediction of auto-ignition delay times in HCCI engines has risen interest on detailed chemical models. This paper described a validated kinetic mechanism for the oxidation of a model Diesel fuel (n-decane and ?-methylnaphthalene). The 3D model for the description of low and high temperature auto-ignition in engines is presented. The behavior of the model fuel is compared with that of n-heptane. Simulations show that the 3D model coupled with the kinetic mechanism can reproduce experimental HCCI and Diesel engine results and that the correct modeling of auto-ignition in the cool flame region is essential in HCCI conditions.

Bounaceur, Roda; Fournet, René; Battin-Leclerc, Frédérique; Jay, S; Da Cruz, A Pires

2007-01-01

194

Dynamic and Structural Gas Turbine Engine Modeling  

NASA Technical Reports Server (NTRS)

Model the interactions between the structural dynamics and the performance dynamics of a gas turbine engine. Generally these two aspects are considered separate, unrelated phenomena and are studied independently. For diagnostic purposes, it is desirable to bring together as much information as possible, and that involves understanding how performance is affected by structural dynamics (if it is) and vice versa. This can involve the relationship between thrust response and the excitation of structural modes, for instance. The job will involve investigating and characterizing these dynamical relationships, generating a model that incorporates them, and suggesting and/or developing diagnostic and prognostic techniques that can be incorporated in a data fusion system. If no coupling is found, at the least a vibration model should be generated that can be used for diagnostics and prognostics related to blade loss, for instance.

Turso, James A.

2003-01-01

195

Academic program models for undergraduate biomedical engineering.  

PubMed

There is a proliferation of medical devices across the globe for the diagnosis and therapy of diseases. Biomedical engineering (BME) plays a significant role in healthcare and advancing medical technologies thus creating a substantial demand for biomedical engineers at undergraduate and graduate levels. There has been a surge in undergraduate programs due to increasing demands from the biomedical industries to cover many of their segments from bench to bedside. With the requirement of multidisciplinary training within allottable duration, it is indeed a challenge to design a comprehensive standardized undergraduate BME program to suit the needs of educators across the globe. This paper's objective is to describe three major models of undergraduate BME programs and their curricular requirements, with relevant recommendations to be applicable in institutions of higher education located in varied resource settings. Model 1 is based on programs to be offered in large research-intensive universities with multiple focus areas. The focus areas depend on the institution's research expertise and training mission. Model 2 has basic segments similar to those of Model 1, but the focus areas are limited due to resource constraints. In this model, co-op/internship in hospitals or medical companies is included which prepares the graduates for the work place. In Model 3, students are trained to earn an Associate Degree in the initial two years and they are trained for two more years to be BME's or BME Technologists. This model is well suited for the resource-poor countries. All three models must be designed to meet applicable accreditation requirements. The challenges in designing undergraduate BME programs include manpower, facility and funding resource requirements and time constraints. Each academic institution has to carefully analyze its short term and long term requirements. In conclusion, three models for BME programs are described based on large universities, colleges, and community colleges. Model 1 is suitable for research-intensive universities. Models 2 and 3 can be successfully implemented in higher education institutions with low and limited resources with appropriate guidance and support from international organizations. The models will continually evolve mainly to meet the industry needs. PMID:25571151

Krishnan, Shankar M

2014-08-01

196

Tail behavior of a Threshold Autoregressive Stochastic Volatility model  

E-print Network

Tail behavior of a Threshold Autoregressive Stochastic Volatility model Aliou DIOP Dominique GUEGAN of the process (t)t. keywords : Tail Behavior, Heavy Tail, Stochastic Volatility Model, Thresh- old as a particular model of the Stochastic Autoregressive Volatility (SARV) model introduced by Andersen (1994

Boyer, Edmond

197

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 tenth reporting period (January 1-March 31, 2000), EER and NETL R and D group continued to work on Tasks 2, 3, 4, and 5. Information regarding these tasks will be included in the next Quarterly Report. This report includes (Appendix 1) a conceptual design study for the introduction of biomass reburning in a working coal-fired utility boiler. This study was conducted under the coordinated SBIR program funded by the U. S. Department of Agriculture.

Vladimir Zamansky; David Moyeda; Mark Sheldon

2000-04-28

198

A Consultative Model for Providing Behavioral Supports to Children with Challenging Behavior.  

ERIC Educational Resources Information Center

This paper presents a consultative model for providing behavioral supports within the context of a public school setting to students with developmental disabilities who display challenging behaviors. The suggested model is contrasted with the traditional consultation model in which a consultant comes from outside the immediate problem situation,…

Wheeler, John J.; Redinius, Patrick

199

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

Microsoft Academic Search

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

Amit Shyam; John E. Allison; Christopher J. Szczepanski; Tresa M. Pollock; J. Wayne Jones

2007-01-01

200

Selection, evolution of behavior and animal models in behavioral neuroscience  

Microsoft Academic Search

We investigated whether genetic differences in various forms of intraspecific aggression and anxiety in four different genetic lines of mice (i.e. wild, outbred Swiss-CD1, inbred DBA\\/2 and inbred C57\\/BL6N) may reflect modifications in behavioral strategy. Experiments 1 and 2 used ethologically based paradigms to analyze aggressive and anxiety responses both in social (i.e. aggression) and non-social (i.e. novel environment exploration)

Stefano Parmigiani; Paola Palanza; John Rodgersb; Piers Francesco Ferrari

1999-01-01

201

Analyzing the emotional outcomes of the online search behavior with search engines  

Microsoft Academic Search

The affective component has been acknowledged as critical to understand information search behavior and user–computer interactions. There is a lack of studies that analyze the emotions that the user feels when searching for information about products with search engines. The present study analyzes the emotional outcomes of the online search process, taking into account the user’s (a) perceptions of success

Carlos Flavián-Blanco; Raquel Gurrea-Sarasa; Carlos Orús-Sanclemente

2011-01-01

202

Cheating in College and its Influence on Ethical Behavior in Professional Engineering Practice  

Microsoft Academic Search

Research has demonstrated that engineering undergraduates report rates of cheating higher than those in most other disciplines and that students who cheat in college are more likely to make unethical decisions as professionals. To explore the relationship between academic and professional ethical behavior, the authors launched the Work Experience Study (WES) that examines students' decision-making processes in situations where they

Trevor S. Harding; Cynthia J. Finelli; Donald D. Carpenter

2006-01-01

203

Photothermal investigation of the thermal shock behavior of alumina ceramics for engine components  

E-print Network

Photothermal investigation of the thermal shock behavior of alumina ceramics for engine components of alumina ceramic materials (96% Al2O3/3% SiO2/0.9% MgO) treated by applying high temperature and high pressure, a process known as ASPRO conversion technology. Alumina ceramics subjected to ASPRO treatment

Mandelis, Andreas

204

Engineering Positive Organizational Behavior and managing the Psychological Capital for learning effectiveness  

Microsoft Academic Search

Social Intelligence has been a living concept for quite some time as an offshoot of Emotional Intelligence and has been used in engineering. Its usefulness in individual context has found several applications in developing individual effectiveness. Several researchers have expanded the concept to organizational development, and organizational effectiveness using modern concepts of Positive Organizational Behavior (POB). The POB has been

Hamid Khan

2011-01-01

205

Experimental and analytical tools for evaluation of Stirling engine rod seal behavior  

NASA Technical Reports Server (NTRS)

The first year of a two year experimental and analytical program is reported. The program is directed at the elastohydrodynamic behavior of sliding elastomeric rod seals for the Stirling engine. During the year, experimental and analytical tools were developed for evaluating seal leakage, seal friction, and the fluid film thickness at the seal/cylinder interface.

Krauter, A. I.; Cheng, H. S.

1979-01-01

206

Ecological Engineering 20 (2003) 379387 Engineering role models: do non-human  

E-print Network

for food and survival. Similarly, `keystone species' have greater impacts on community or ecosystem reserved. Keywords: Ecosystem engineers; Biomimicry; Ecosystem function; Keystone species; Exotic speciesEcological Engineering 20 (2003) 379­387 Engineering role models: do non-human species have

Rosemond, Amy Daum

207

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

208

Cognitive engineering models in space systems  

NASA Technical Reports Server (NTRS)

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

Mitchell, Christine M.

1992-01-01

209

Behavioral Characterization of Mouse Models of Neuroferritinopathy  

PubMed Central

Ferritin is the main intracellular protein of iron storage with a central role in the regulation of iron metabolism and detoxification. Nucleotide insertions in the last exon of the ferritin light chain cause a neurodegenerative disease known as Neuroferritinopathy, characterized by iron deposition in the brain, particularly in the cerebellum, basal ganglia and motor cortex. The disease progresses relentlessly, leading to dystonia, chorea, motor disability and neuropsychiatry features. The characterization of a good animal model is required to compare and contrast specific features with the human disease, in order to gain new insights on the consequences of chronic iron overload on brain function and behavior. To this aim we studied an animal model expressing the pathogenic human FTL mutant 498InsTC under the phosphoglycerate kinase (PGK) promoter. Transgenic (Tg) mice showed strong accumulation of the mutated protein in the brain, which increased with age, and this was accompanied by brain accumulation of ferritin/iron bodies, the main pathologic hallmark of human neuroferritinopathy. Tg-mice were tested throughout development and aging at 2-, 8- and 18-months for motor coordination and balance (Beam Walking and Footprint tests). The Tg-mice showed a significant decrease in motor coordination at 8 and 18 months of age, with a shorter latency to fall and abnormal gait. Furthermore, one group of aged naïve subjects was challenged with two herbicides (Paraquat and Maneb) known to cause oxidative damage. The treatment led to a paradoxical increase in behavioral activation in the transgenic mice, suggestive of altered functioning of the dopaminergic system. Overall, data indicate that mice carrying the pathogenic FTL498InsTC mutation show motor deficits with a developmental profile suggestive of a progressive pathology, as in the human disease. These mice could be a powerful tool to study the neurodegenerative mechanisms leading to the disease and help developing specific therapeutic targets. PMID:25689865

Buffoli, Barbara; Rodella, Luigi F.; Cremona, Ottavio; Arosio, Paolo; Cirulli, Francesca

2015-01-01

210

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

211

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.

2006-05-01

212

Tools and Behavioral Abstraction: A Direction for Software Engineering  

E-print Network

. ­ that is hard to misuse, both accidentally and maliciously. Letting an operator open up the landing gear have come to appreciate types (enforced either statically or dynamically), we have developed models

Leino, K. Rustan M.

213

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

SciTech Connect

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 operated on an engine dynamometer. Based on these results a shift strategy for optimized fuel economy is established and engine control strategies for various levels of hybridization are being discussed. The strategies are evaluated on the Urban drive cycle, differences in engine behavior are investigated and the estimated fuel economy and NO{sub x} emissions are calculated. Future work will include dynamic testing of these strategies and powertrain configurations as well as individual powertrain components on a vehicle platform, called 'Mobile Advanced Technology Testbed' (MATT), that was developed and built at Argonne National Laboratory.

Wallner, T.; Lohse-Busch, H.; Shidore, N.; Energy Systems

2009-05-01

214

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

SciTech Connect

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 operated on an engine dynamometer. Based on these results a shift strategy for optimized fuel economy is established and engine control strategies for various levels of hybridization are being discussed. The strategies are evaluated on the Urban drive cycle, differences in engine behavior are investigated and the estimated fuel economy and NO{sub x} emissions are calculated. Future work will include dynamic testing of these strategies and powertrain configurations as well as individual powertrain components on a vehicle platform, called Mobile Advanced Technology Testbed (MATT), that was developed and built at Argonne National Laboratory.

Wallner, T.; Lohse-Busch, H.; Shidore, N.; Energy Systems

2009-05-01

215

Global optimization of bilinear engineering design models  

SciTech Connect

Recently Quesada and Grossmann have proposed a global optimization algorithm for solving NLP problems involving linear fractional and bilinear terms. This model has been motivated by a number of applications in process design. The proposed method relies on the derivation of a convex NLP underestimator problem that is used within a spatial branch and bound search. This paper explores the use of alternative bounding approximations for constructing the underestimator problem. These are applied in the global optimization of problems arising in different engineering areas and for which different relaxations are proposed depending on the mathematical structure of the models. These relaxations include linear and nonlinear underestimator problems. Reformulations that generate additional estimator functions are also employed. Examples from process design, structural design, portfolio investment and layout design are presented.

Grossmann, I.; Quesada, I.

1994-12-31

216

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

217

ZMOTTO- MODELING THE INTERNAL COMBUSTION ENGINE  

NASA Technical Reports Server (NTRS)

The ZMOTTO program was developed to model mathematically a spark-ignited internal combustion engine. ZMOTTO is a large, general purpose program whose calculations can be established at five levels of sophistication. These five models range from an ideal cycle requiring only thermodynamic properties, to a very complex representation demanding full combustion kinetics, transport properties, and poppet valve flow characteristics. ZMOTTO is a flexible and computationally economical program based on a system of ordinary differential equations for cylinder-averaged properties. The calculations assume that heat transfer is expressed in terms of a heat transfer coefficient and that the cylinder average of kinetic plus potential energies remains constant. During combustion, the pressures of burned and unburned gases are assumed equal and their heat transfer areas are assumed proportional to their respective mass fractions. Even the simplest ZMOTTO model provides for residual gas effects, spark advance, exhaust gas recirculation, supercharging, and throttling. In the more complex models, 1) finite rate chemistry replaces equilibrium chemistry in descriptions of both the flame and the burned gases, 2) poppet valve formulas represent fluid flow instead of a zero pressure drop flow, and 3) flame propagation is modeled by mass burning equations instead of as an instantaneous process. Input to ZMOTTO is determined by the model chosen. Thermodynamic data is required for all models. Transport properties and chemical kinetics data are required only as the model complexity grows. Other input includes engine geometry, working fluid composition, operating characteristics, and intake/exhaust data. ZMOTTO accommodates a broad spectrum of reactants. The program will calculate many Otto cycle performance parameters for a number of consecutive cycles (a cycle being an interval of 720 crankangle degrees). A typical case will have a number of initial ideal cycles and progress through levels of nonideal cycles. ZMOTTO has restart capabilities and permits multicycle calculations with parameters varying from cycle to cycle. ZMOTTO is written in FORTRAN IV (IBM Level H) but has also been compiled with IBM VSFORTRAN (1977 standard). It was developed on an IBM 3033 under the TSS operating system and has also been implemented under MVS. Approximately 412K of 8 bit bytes of central memory are required in a nonpaging environment. ZMOTTO was developed in 1985.

Zeleznik, F. J.

1994-01-01

218

GETRAN: A generic, modularly structured computer code for simulation of dynamic behavior of aero- and power generation gas turbine engines  

Microsoft Academic Search

The design concept, the theoretical background essential for the development of the modularly structured simulation code GETRAN, and several critical simulation cases are presented in this paper. The code being developed under contract with NASA Lewis Research Center is capable of simulating the nonlinear dynamic behavior of single- and multispool core engines, turbofan engines, and power generation gas turbine engines

M. T. Schobeiri; M. Attia; C. Lippke

1994-01-01

219

Work in progress - A mixed-methods approach to developing an instrument measuring engineering students' positive ethical behavior  

Microsoft Academic Search

Ethics education and the drive to produce ethical professional engineers is an important focus of one body of research on engineering education. This research often defines the positive outcome of ethics education as students and professional engineers choosing not to engage in unethical behavior. This paper discusses a portion of a larger research project and details efforts to identify and

Matthew A. Holsapple; Cynthia Finelli; Donald Carpenter; Trevor Harding; Janel Sutkus

2009-01-01

220

Software Engineering Laboratory (SEL) cleanroom process model  

NASA Technical Reports Server (NTRS)

The Software Engineering Laboratory (SEL) cleanroom process model is described. The term 'cleanroom' originates in the integrated circuit (IC) production process, where IC's are assembled in dust free 'clean rooms' to prevent the destructive effects of dust. When applying the clean room methodology to the development of software systems, the primary focus is on software defect prevention rather than defect removal. The model is based on data and analysis from previous cleanroom efforts within the SEL and is tailored to serve as a guideline in applying the methodology to future production software efforts. The phases that are part of the process model life cycle from the delivery of requirements to the start of acceptance testing are described. For each defined phase, a set of specific activities is discussed, and the appropriate data flow is described. Pertinent managerial issues, key similarities and differences between the SEL's cleanroom process model and the standard development approach used on SEL projects, and significant lessons learned from prior cleanroom projects are presented. It is intended that the process model described here will be further tailored as additional SEL cleanroom projects are analyzed.

Green, Scott; Basili, Victor; Godfrey, Sally; Mcgarry, Frank; Pajerski, Rose; Waligora, Sharon

1991-01-01

221

Computational modeling for eco engineering: Making the connections between engineering and ecology (Invited)  

NASA Astrophysics Data System (ADS)

Ecological engineering, or eco engineering, is an emerging field in the study of integrating ecology and engineering, concerned with the design, monitoring, and construction of ecosystems. According to Mitsch (1996) 'the design of sustainable ecosystems intends to integrate human society with its natural environment for the benefit of both'. Eco engineering emerged as a new idea in the early 1960s, and the concept has seen refinement since then. As a commonly practiced field of engineering it is relatively novel. Howard Odum (1963) and others first introduced it as 'utilizing natural energy sources as the predominant input to manipulate and control environmental systems'. Mtisch and Jorgensen (1989) were the first to define eco engineering, to provide eco engineering principles and conceptual eco engineering models. Later they refined the definition and increased the number of principles. They suggested that the goals of eco engineering are: a) the restoration of ecosystems that have been substantially disturbed by human activities such as environmental pollution or land disturbance, and b) the development of new sustainable ecosystems that have both human and ecological values. Here a more detailed overview of eco engineering is provided, particularly with regard to how engineers and ecologists are utilizing multi-dimensional computational models to link ecology and engineering, resulting in increasingly successful project implementation. Descriptions are provided pertaining to 1-, 2- and 3-dimensional hydrodynamic models and their use at small- and large-scale applications. A range of conceptual models that have been developed to aid the in the creation of linkages between ecology and engineering are discussed. Finally, several case studies that link ecology and engineering via computational modeling are provided. These studies include localized stream rehabilitation, spawning gravel enhancement on a large river system, and watershed-wide floodplain modeling of the Sacramento River Valley.

Bowles, C.

2013-12-01

222

Generating transformation rules from examples for behavioral models  

Microsoft Academic Search

Behavioral UML models like sequence diagrams (SD) lack sufficient formal semantics, making it difficult to build automated tools for their analysis, simulation and validation. A common approach to circumvent the problem is to map these models to more formal representations. In this context, many works propose a rule-based approach to automatically translate behavioral models like SD into colored Petri nets

Marouane Kessentini; Manuel Wimmer; Houari Sahraoui; Mounir Boukadoum

2010-01-01

223

Steel Shear Walls, Behavior, Modeling and Design  

NASA Astrophysics Data System (ADS)

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 earthquakes and based on laboratory cyclic tests indicates that the systems are quite ductile and can be designed in an economical way to have sufficient stiffness, strength, ductility and energy dissipation capacity to resist seismic effects of strong earthquakes. This paper, after summarizing the past research, presents the results of two tests of an innovative steel shear wall system where the boundary elements are concrete-filled tubes. Then, a review of currently available analytical models of steel shear walls is provided with a discussion of capabilities and limitations of each model. We have observed that the tension only "strip model", forming the basis of the current AISC seismic design provisions for steel shear walls, is not capable of predicting the behavior of steel shear walls with length-to-thickness ratio less than about 600 which is the range most common in buildings. The main reasons for such shortcomings of the AISC seismic design provisions for steel shear walls is that it ignores the compression field in the shear walls, which can be significant in typical shear walls. The AISC method also is not capable of incorporating stresses in the shear wall due to overturning moments. A more rational seismic design procedure for design of shear walls proposed in 2000 by the author is summarized in the paper. The design method, based on procedures used for design of steel plate girders, takes into account both tension and compression stress fields and is applicable to all values of length-to-thickness ratios of steel shear walls. The method is also capable of including the effect of overturning moments and any normal forces that might act on the steel shear wall.

Astaneh-Asl, Abolhassan

2008-07-01

224

17. YAZOO BACKWATER PUMPING STATION MODEL, YAZOO RIVER BASIN. ENGINEERS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. YAZOO BACKWATER PUMPING STATION MODEL, YAZOO RIVER BASIN. ENGINEERS EXAMINING MODEL PUMPS, VIEW FROM MODEL BED. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

225

Reverse engineering gene networks: Integrating genetic perturbations with dynamical modeling  

E-print Network

Reverse engineering gene networks: Integrating genetic perturbations with dynamical modeling Jesper contained in the genetic circuit. A natural plan of attack is to use a forward engineering approach, wherebyDynamics and Department of Biomedical Engineering, Boston University, Boston, MA 02215; Division of Computational Biology

Babu, M. Madan

226

ILLINOIS RAILROAD ENGINEERING Using the RTC Simulation Model to  

E-print Network

Slide 1 ILLINOIS RAILROAD ENGINEERING Using the RTC Simulation Model to Evaluate Effects of Operating Heterogeneity on Railway Capacity Mark Dingler September 12, 2008 The William W. Hay Railroad Engineering Seminar Series #12;Slide 2 ILLINOIS RAILROAD ENGINEERING Outline · Background · Methodology

Barkan, Christopher P.L.

227

Model-Driven Engineering of Industrial Process Control Applications  

E-print Network

Model-Driven Engineering of Industrial Process Control Applications Tomaz Lukman1 , Giovanni Godena contributions of this paper are: an MDE approach to the engineering of industrial process control applications-driven engineering approach to the development of industrial process control software, which is based on the Proc

Gray, Jeffrey G.

228

LUDOCORE: A logical game engine for modeling videogames  

Microsoft Academic Search

LUDOCORE is a logical “game engine”, linking game rules as reasoned about by game designers to the formal logic used by automated reasoning tools in AI. A key challenge in designing this bridge is engineering a concise, safe, and flexible representation that is compatible with the semantics of the games that logical models created with our engine intend to represent.

Adam M. Smith; Mark J. Nelson; Michael Mateas

2010-01-01

229

Modelling Mixing Mechanisms Professor Ian Guymer, Professor of Civil Engineering  

E-print Network

Modelling Mixing Mechanisms Professor Ian Guymer, Professor of Civil Engineering School of Engineering, University of Warwick CIVIL RESEARCH GROUP SEMINAR Wednesday 26th November 2014 4pm Conveyance networks are common in many aspects of civil engineering hydraulics, e.g. rivers, urban drainage

Davies, Christopher

230

MODELING AND CONTROL OF A DIESEL HCCI ENGINE  

E-print Network

MODELING AND CONTROL OF A DIESEL HCCI ENGINE J. Chauvin A. Albrecht G. Corde N. Petit Institut Abstract: This article focuses on the control of a Diesel engine airpath. We propose a detailed description of the airpath of a Diesel HCCI engine supported by experimental results. Moreover, we propose a simple, yet

Paris-Sud XI, Université de

231

Data and model uncertainties in complex aerospace engineering systems.  

E-print Network

Data and model uncertainties in complex aerospace engineering systems. Capiez-Lernout, E.1,a of aerospace engineering constituted of a satellite coupled with its launcher. First, a parametric of Engineering Mechanics Leopold-Franzens University A-6020, Innsbruck. Corresponding author. Preprint submitted

Paris-Sud XI, Université de

232

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

233

Physical modelling in Geotechnical Earthquake Engineering – 2: Session Report  

E-print Network

International Journal of Physical Modelling in Geotechnics Physical modelling in Geotechnical Earthquake Engineering --Manuscript Draft-- Manuscript Number: IJPMG-D-14-00033R1 Full Title: Physical modelling in Geotechnical Earthquake Engineering... an important role in Geotechnical Earthquake Engineering. It is used to understand failure mechanisms and study the dynamic behaviour of a wide variety of dynamic problems with earthquake and other dynamic loading. As in the previous ICPMG conferences, Perth...

Madabhushi, Gopal

2015-01-01

234

Work in progress — Developmental engineering: Using observation for understanding child behaviors as precursors to engineering thinking  

Microsoft Academic Search

Children's experiences in early childhood have significant lasting effects in their overall development and in the United States today the majority of young children spend considerable amounts of time in early childhood education settings. At the national level, there is an expressed concern about the low levels of student interest and success in science, technology, engineering, and mathematics (STEM). Bringing

Diana Bairaktarova; Demetra Evangelou; Christina Citta

2011-01-01

235

Patronage Behavior of Apparel Shopping: Part II. Testing a Patronage Model of Consumer Behavior  

Microsoft Academic Search

This is the second part of a two-part paper which investigates patronage choice behavior in apparel shopping. Part II illustrates how a conventional patronage model can be tested and extended Part of Darden's (1980) Patronage Model of Consumer Behavior was investigated by utilizing regression analyses. In addition to the five direct linkages Darden proposed, this study identified two more direct

Soyeon Shim; Antigone Kotsiopulos

1992-01-01

236

Modelling of diesel engine fuelled with biodiesel using engine simulation software  

NASA Astrophysics Data System (ADS)

This paper is about modelling of a diesel engine that operates using biodiesel fuels. The model is used to simulate or predict the performance and combustion of the engine by simplified the geometry of engine component in the software. The model is produced using one-dimensional (1D) engine simulation software called GT-Power. The fuel properties library in the software is expanded to include palm oil based biodiesel fuels. Experimental works are performed to investigate the effect of biodiesel fuels on the heat release profiles and the engine performance curves. The model is validated with experimental data and good agreement is observed. The simulation results show that combustion characteristics and engine performances differ when biodiesel fuels are used instead of no. 2 diesel fuel.

Said, Mohd Farid Muhamad; Said, Mazlan; Aziz, Azhar Abdul

2012-06-01

237

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 3D…

Hartman, Nathan W.

2006-01-01

238

Towards a detailed soot model for internal combustion engines  

Microsoft Academic Search

In this work, we present a detailed model for the formation of soot in internal combustion engines describing not only bulk quantities such as soot mass, number density, volume fraction, and surface area but also the morphology and chemical composition of soot aggregates. The new model is based on the Stochastic Reactor Model (SRM) engine code, which uses detailed chemistry

Sebastian Mosbach; Matthew S. Celnik; Abhijeet Raj; Markus Kraft; Hongzhi R. Zhang; Shuichi Kubo; Kyoung-Oh Kim

2009-01-01

239

Combustion system CFD modeling at GE Aircraft Engines  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

240

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

241

Perceptions of Education, Engineering, and Nursing Faculty Members Regarding their Role in Helping Students Develop Professional Behavior  

Microsoft Academic Search

In conducting this study, we used qualitative and quantitative research techniques to determine faculty members' perceptions of (a) their role in teaching professional behavior, (b) the professional behaviors that are most important for students to develop, and (c) the methods used to help education, engineering, and nursing students develop professional behavior. Differences were identified between the three groups of faculty

Sandra Nadelson; Louis Nadelson; Richard Osguthorpe

2009-01-01

242

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

243

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

244

REAL & MODEL EXTERNAL CHARACTERISTICS OF COMBUSTION ENGINE  

Microsoft Academic Search

The characteristics of combustion engines be calculated from dawn. The characteristics, they are resulting from current theory, are giving as a smooth curves. This is a generalization. The current characteristics of combustion engines are much more complicated. The present engines which to fulfill have the rigorous norms of emission of toxic components of exhaust gases, they be controlled of many

Lech J. Sitnik

245

Universal Behavior of a Cyclic Oxidation Model  

NASA Technical Reports Server (NTRS)

A mathematical model has been generated to represent the iterative, discrete growth and spallation processes associated with cyclic oxidation. Parabolic growth kinetics (k(sub p)) over and a constant spall area (F(sub A)) were assumed, with spalling occurring interfacially at the thickest regions of the scale. Although most models require numerical techniques, the regularity and simplicity of this progression permitted an approximation by algebraic expressions. Normalization could now be performed to reflect all parametric effects, and a universal cyclic oxidation response was generated: W(sub u) = 1/2 {3J(sub u)(sup 1/2)+ J(sub u)(sup 3/2)} where W, is weight change normalized by the maximum and J(sub u) is the cycle number normalized by the number to reach maximum. Similarly, the total amount of metal consumed was represented by a single normalized curve. The factor [(S(sub c)-l)(raised dot)sqrt(F(sub A)k(sub p)DELTAt)] was identified as a general figure of merit, where S(sub c) is the mass ratio of oxide to oxygen and DELTAt is the cycle duration. A cyclic oxidation failure map was constructed, in normalized k(sub p)-F(sub A) space, as defined by the locus of points corresponding to a critical amount of metal consumption in a given time. All three constructions describe behavior for every value of growth rate, spall fraction, and cycle duration by means of single curves, but with two branches corresponding to the times before and after steady state is achieved.

Smialek, James L.

2003-01-01

246

Orbital Debris Engineering Model (ORDEM) v.3  

NASA Technical Reports Server (NTRS)

A model of the manmade orbital debris environment is required by spacecraft designers, mission planners, and others in order to understand and mitigate the effects of the environment on their spacecraft or systems. A manmade environment is dynamic, and can be altered significantly by intent (e.g., the Chinese anti-satellite weapon test of January 2007) or accident (e.g., the collision of Iridium 33 and Cosmos 2251 spacecraft in February 2009). Engineering models are used to portray the manmade debris environment in Earth orbit. The availability of new sensor and in situ data, the re-analysis of older data, and the development of new analytical and statistical techniques has enabled the construction of this more comprehensive and sophisticated model. The primary output of this model is the flux [#debris/area/time] as a function of debris size and year. ORDEM may be operated in spacecraft mode or telescope mode. In the former case, an analyst defines an orbit for a spacecraft and "flies" the spacecraft through the orbital debris environment. In the latter case, an analyst defines a ground-based sensor (telescope or radar) in terms of latitude, azimuth, and elevation, and the model provides the number of orbital debris traversing the sensor's field of view. An upgraded graphical user interface (GUI) is integrated with the software. This upgraded GUI uses project-oriented organization and provides the user with graphical representations of numerous output data products. These range from the conventional flux as a function of debris size for chosen analysis orbits (or views), for example, to the more complex color-contoured two-dimensional (2D) directional flux diagrams in local spacecraft elevation and azimuth.

Matney, Mark; Krisko, Paula; Xu, Yu-Lin; Horstman, Matthew

2013-01-01

247

A simplified dynamic model of Space Shuttle Main Engine  

NASA Technical Reports Server (NTRS)

A simplified dynamic model is presented of the Space Shuttle Main Engine (SSME) dynamics valid within the range of operation of the engine. This model is obtained by linking the linearized point models obtained at 25 different operating points of SSME. The simplified model was developed for use with a model-based diagnostic scheme for failure detection and diagnostics studies, as well as control design purposes.

Duyar, Ahmet; Eldem, Vasfi; Merrill, Walter; Guo, Ten-Huei

1991-01-01

248

A simplified dynamic model of the Space Shuttle main engine  

NASA Technical Reports Server (NTRS)

A simplified model is presented of the space shuttle main engine (SSME) dynamics valid within the range of operation of the engine. This model is obtained by linking the linearized point models obtained at 25 different operating points of SSME. The simplified model was developed for use with a model-based diagnostic scheme for failure detection and diagnostics studies, as well as control design purposes.

Duyar, Ahmet; Eldem, Vasfi; Merrill, Walter; Guo, Ten-Huei

1991-01-01

249

Hierarchical models of behavior and prefrontal function  

E-print Network

is on the instrumental structure of behavior or its correlational structure. Human behavior displays instrumental necessary for later ones. As an illus- tration of how instrumental structure can give rise to hierarchy structure in the sense that action sequences bring about valued or desired outcomes, and successive actions

Botvinick, Matthew

250

Neural Modeling and Control of Diesel Engine with Pollution Constraints  

E-print Network

The paper describes a neural approach for modelling and control of a turbocharged Diesel engine. A neural model, whose structure is mainly based on some physical equations describing the engine behaviour, is built for the rotation speed and the exhaust gas opacity. The model is composed of three interconnected neural submodels, each of them constituting a nonlinear multi-input single-output error model. The structural identi?cation and the parameter estimation from data gathered on a real engine are described. The neural direct model is then used to determine a neural controller of the engine, in a specialized training scheme minimising a multivariable criterion. Simulations show the effect of the pollution constraint weighting on a trajectory tracking of the engine speed. Neural networks, which are ?exible and parsimonious nonlinear black-box models, with universal approximation capabilities, can accurately describe or control complex nonlinear systems, with little a priori theoretical knowledge. The present...

Ouladsine, Mustapha; Dovifaaz, Xavier; 10.1007/s10846-005-3806-y

2009-01-01

251

Modeling Carrier Behavior in Sequential Auction Transportation Markets  

E-print Network

Modeling Carrier Behavior in Sequential Auction Transportation Markets M. A. Figliozzi, University ______________________________________________________________________________ August 10-15, 2003 2 Title: Modeling Carrier Behavior in Sequential Auction Transportation Markets Miguel Phone: 301-405-0752 Fax: 301-405-2585 eMail: masmah@umd.edu Abstract Online markets for transportation

Bertini, Robert L.

252

The combined model of influencing on-line consumer behavior  

Microsoft Academic Search

Combining the views from the Decomposed Theory of Planned Behavior and Technology Acceptance Model, this study proposes an integrated opinion to construct on-line consuming behavior patterns for travel. The nonlinear fuzzy network model were adopted to test and verify the sample data. The method of convenience sampling was employed and the questionnaires were distributed through e-mail sending, or were brought

Wen-Bao Lin; Ming-Kuen Wang; Kevin P. Hwang

2010-01-01

253

CSEM WP 125 Testing Strategic Models of Firm Behavior in  

E-print Network

CSEM WP 125 Testing Strategic Models of Firm Behavior in Restructured Electricity Markets: A Case 2004 This paper is part of the Center for the Study of Energy Markets (CSEM) Working Paper Series. CSEM;Testing Strategic Models of Firm Behavior in Restructured Electricity Markets: A Case Study of ERCOT Ali

California at Berkeley. University of

254

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

255

Behavioral modeling of digital IC input and output ports  

Microsoft Academic Search

This paper addresses the development of accurate and efficient behavioral models of digital integrated circuit input and output ports for signal integrity simulations and timing analyses. The modeling process is described and applied to the characterization of actual devices

I. S. Stievano; Z. Chen; D. Becker; F. G. Canavero; G. Katopis; I. A. Maio

2001-01-01

256

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. PMID:23105914

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

2012-01-01

257

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

2013-09-01

258

Engineering Models Ease and Speed Prototyping  

NASA Technical Reports Server (NTRS)

NASA astronauts plan to return to the Moon as early as 2015 and establish a lunar base, from which 6-month flights to Mars would be launched by 2030. Essential to this plan is the Ares launch vehicle, NASA s next-generation spacecraft that will, in various iterations, be responsible for transporting all equipment and personnel to the Moon, Mars, and beyond for the foreseeable future. The Ares launch vehicle is powered by the J-2X propulsion system, with what will be the world s largest rocket nozzles. One of the conditions that engineers carefully consider in designing rocket nozzles particularly large ones is called separation phenomenon, which occurs when outside ambient air is sucked into the nozzle rim by the relatively low pressures of rapidly expanding exhaust gasses. This separation of exhaust gasses from the side-wall imparts large asymmetric transverse loads on the nozzle, deforming the shape and thus perturbing exhaust flow to cause even greater separation. The resulting interaction can potentially crack the nozzle or break actuator arms that control thrust direction. Side-wall loads are extremely difficult to measure directly, and, until now, techniques were not available for accurately predicting the magnitude and frequency of the loads. NASA researchers studied separation phenomenon in scale-model rocket nozzles, seeking to use measured vibration on these nozzle replicas to calculate the unknown force causing the vibrations. Key to this approach was the creation of a computer model accurately representing the nozzle as well as the test cell.

2008-01-01

259

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. PMID:24124436

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

2013-01-01

260

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

PubMed

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. PMID:24124436

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

2013-04-01

261

Control Engineering: New Trends with OO Modelling Approach  

Microsoft Academic Search

The paper deals with two examples, which show the efficiency of OO modelling approach in control engineering. The first example - an optimization of three tank hydraulic control system shows the efficiency of the OO modelling approach in control engineering education. A very efficient environment is the combination of Matlab Simulink and a Modelica based OO environment Dymola. Two different

Borut Zupancic; Rihard Karba

2007-01-01

262

Model Driven Engineering for MPSoC Design Space Exploration  

E-print Network

Model Driven Engineering for MPSoC Design Space Exploration Marcio F. da S. Oliveira, Eduardo W This paper presents a Model Driven Engineering approach for MPSoC Design Space Exploration (DSE) to deal-Aided Design (CAD) General Terms Design, Measurement, Performance Keywords Design space exploration, multi

Wagner, Flávio Rech

263

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

264

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

265

State variable modeling of the integrated engine and aircraft dynamics  

NASA Astrophysics Data System (ADS)

This study explores the dynamic characteristics of the combined aircraft-engine system, based on the general theory of the state variables for linear and nonlinear systems, with details leading first to the separate formulation of the longitudinal and the lateral directional state variable models, followed by the merging of the aircraft and engine models into a single state variable model. The linearized equations were expressed in a matrix form and the engine dynamics was included in terms of variation of thrust following a deflection of the throttle. The linear model of the shaft dynamics for a two-spool jet engine was derived by extending the one-spool model. The results include the discussion of the thrust effect upon the aircraft response when the thrust force associated with the engine has a sizable moment arm with respect to the aircraft center of gravity for creating a compensating moment.

Rotaru, Constantin; Sprinţu, Iuliana

2014-12-01

266

Anticipatory behavior in lane changing models  

E-print Network

Actions performed by drivers in case of lane changing behavior are usually the result of some plan the driver has in mind. This involves anticipating future scenarios and persisting in order to execute the plan. The objective ...

Rao, Anita (Anita Anant)

2006-01-01

267

The Advanced Modeling, Simulation and Analysis Capability Roadmap Vision for Engineering  

NASA Technical Reports Server (NTRS)

This paper summarizes a subset of the Advanced Modeling Simulation and Analysis (AMSA) Capability Roadmap that was developed for NASA in 2005. The AMSA Capability Roadmap Team was chartered to "To identify what is needed to enhance NASA's capabilities to produce leading-edge exploration and science missions by improving engineering system development, operations, and science understanding through broad application of advanced modeling, simulation and analysis techniques." The AMSA roadmap stressed the need for integration, not just within the science, engineering and operations domains themselves, but also across these domains. Here we discuss the roadmap element pertaining to integration within the engineering domain, with a particular focus on implications for future observatory missions. The AMSA products supporting the system engineering function are mission information, bounds on information quality, and system validation guidance. The Engineering roadmap element contains 5 sub-elements: (1) Large-Scale Systems Models, (2) Anomalous Behavior Models, (3) advanced Uncertainty Models, (4) Virtual Testing Models, and (5) space-based Robotics Manufacture and Servicing Models.

Zang, Thomas; Lieber, Mike; Norton, Charles; Fucik, Karen

2006-01-01

268

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

269

Human factors engineering program review model  

SciTech Connect

The staff of the Nuclear Regulatory Commission is performing nuclear power plant design certification reviews based on a design process plan that describes the human factors engineering (HFE) program elements that are necessary and sufficient to develop an acceptable detailed design specification and an acceptable implemented design. There are two principal reasons for this approach. First, the initial design certification applications submitted for staff review did not include detailed design information. Second, since human performance literature and industry experiences have shown that many significant human factors issues arise early in the design process, review of the design process activities and results is important to the evaluation of an overall design. However, current regulations and guidance documents do not address the criteria for design process review. Therefore, the HFE Program Review Model (HFE PRM) was developed as a basis for performing design certification reviews that include design process evaluations as well as review of the final design. A central tenet of the HFE PRM is that the HFE aspects of the plant should be developed, designed, and evaluated on the basis of a structured top-down system analysis using accepted HFE principles. The HFE PRM consists of ten component elements. Each element in divided into four sections: Background, Objective, Applicant Submittals, and Review Criteria. This report describes the development of the HFE PRM and gives a detailed description of each HFE review element.

Not Available

1994-07-01

270

Engineering model 8-cm thruster subsystem  

NASA Technical Reports Server (NTRS)

An Engineering Model (EM) 8 cm Ion Thruster Propulsion Subsystem was developed for operation at a thrust level 5 mN (1.1 mlb) at a specific impulse 1 sub sp = 2667 sec with a total system input power P sub in = 165 W. The system dry mass is 15 kg with a mercury-propellant-reservoir capacity of 8.75 kg permitting uninterrupted operation for about 12,500 hr. The subsystem can be started from a dormant condition in a time less than or equal to 15 min. The thruster has a design lifetime of 20,000 hr with 10,000 startup cycles. A gimbal unit is included to provide a thrust vector deflection capability of + or - 10 degrees in any direction from the zero position. The EM subsystem development program included thruster optimization, power-supply circuit optimization and flight packaging, subsystem integration, and subsystem acceptance testing including a cyclic test of the total propulsion package.

Herron, B. G.; Hyman, J.; Hopper, D. J.; Williamson, W. S.; Dulgeroff, C. R.; Collett, C. R.

1978-01-01

271

Algorithms for Reverse Engineering Boundary Representation Models  

E-print Network

point data into regions; creating translational and rotational surfaces with smooth, constrained by CAD/CAM systems. There is a wide diversity of reverse engineering methods for converting measured data CAD/CAM sys- tems. The current situation in reverse engineering is somewhat similar. For free

Martin, Ralph R.

272

Financial modeling on the cell broadband engine  

Microsoft Academic Search

High performance computing is critical for financial markets where analysts seek to accelerate complex optimizations such as pricing engines to maintain a competitive edge. In this paper we investigate the performance of financial workloads on the Sony-Toshiba- IBM Cell Broadband Engine, a heterogeneous multicore chip architected for intensive gaming applications and high performance computing. We analyze the use of Monte

Virat Agarwal; Lurng-kuo Liu; David A. Bader

2008-01-01

273

(Non)Issues of Infinite Regress in Modeling Motor Behavior  

Microsoft Academic Search

In the past, infinite regress criticisms that have been raised about models of motor behavior have been reserved for executive-type models (e.g., Beek & Meijer, 1988). On the basis of Gödel's (1930\\/1986) proof that an algorithm cannot prove its own validity, the authors reason that executive- as well as self-organized-type explanatory models of motor behavior have infinite regress difficulties. The

Robert M. Kohl; Haim A. Ben-David

1998-01-01

274

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

275

Modeling Driver Behavior as Sequential Risk-Taking Task  

Microsoft Academic Search

Acceleration models are at the core of operational driving behaviors and include car-following models that capture interactions between a lead and following vehicles. The main assumption in these models is that the behavior of the following vehicle (e.g., change in acceleration) is related directly to a stimulus observed or perceived by the driver, defined relative to the lead vehicle (e.g.,

Samer H. Hamdar; Martin Treiber; Hani S. Mahmassani; Arne Kesting

2008-01-01

276

BEHAVIORAL MODEL SPECIFICATION TOWARDS SIMULATION VALIDATION USING RELATIONAL DATABASES  

E-print Network

and in particular in terms of model validation, it is important to use model repositories. The structure and behavior of dynamical systems can be represented as atomic models having inputs, outputs, states, and functions. Scalable System Entity Structure Modeler with Complexity Measures (SESM/CM) offers a basis

277

MODAL TEST EXPERIENCES WITH A JET ENGINE FAN MODEL  

Microsoft Academic Search

High cycle fatigue in jet engine blades is caused by excessive vibration. Understanding the dynamic response of the bladed disk system is important in determining vibration levels. Modal testing is a useful tool in understanding the dynamic behavior of structures. However, modal tests are not conducted on bladed disks because of the difficulties involved. One problem is that the overall

J. J. Hollkamp; R. W. GORDON

2001-01-01

278

Supercomputer modeling of hydrogen combustion in rocket engines  

NASA Astrophysics Data System (ADS)

Hydrogen being an ecological fuel is very attractive now for rocket engines designers. However, peculiarities of hydrogen combustion kinetics, the presence of zones of inverse dependence of reaction rate on pressure, etc. prevents from using hydrogen engines in all stages not being supported by other types of engines, which often brings the ecological gains back to zero from using hydrogen. Computer aided design of new effective and clean hydrogen engines needs mathematical tools for supercomputer modeling of hydrogen-oxygen components mixing and combustion in rocket engines. The paper presents the results of developing verification and validation of mathematical model making it possible to simulate unsteady processes of ignition and combustion in rocket engines.

Betelin, V. B.; Nikitin, V. F.; Altukhov, D. I.; Dushin, V. R.; Koo, Jaye

2013-08-01

279

Engineering teacher training models and experiences  

NASA Astrophysics Data System (ADS)

Institutions and Organisations that take training seriously and devote time, effort and resources, etc, to their own teams are more likely to succeed, since both initial teacher training and continuous improvement, studies, hours of group discussion, works on innovation and educational research, talks and permanent meetings, etc, will all serve to enhance teaching and its quality. Teachers will be able to introduce new components from previously taught classes into their university teaching which will contribute to improving their work and developing a suitable academic environment to include shared objectives, teachers and students. Moreover, this training will serve to enhance pedagogic innovation, new teaching-learning methodologies and contribute to getting teaching staff involved in respect of the guidelines set out by the EHEA. Bearing in mind that training and motivation can be key factors in any teacher's "performance", their productivity and the quality of their teaching, Teacher Training for a specific post inside the University Organisation is standard practice of so-called Human Resources management and an integral part of a teacher's work; it is a way of professionalising the teaching of the different branches of Engineering. At Madrid Polytechnic University, in the Institute of Educational Sciences (ICE), since it was founded in 1972, we have been working hard with university teaching staff. But it was not until 1992 after carrying out various studies on training needs that we planned and programmed different training actions, offering a wide range of possibilities. Thus, we designed and taught an "Initial Teacher Training Course", as it was first called in 1992, a programme basically aimed to train young Engineering teachers just setting out on their teaching career. In 2006, the name was changed to "Advanced University Teacher Training Course". Subsequently, with the appearance of the Bologna Declaration and the creation of the European Higher Education Area, we renewed the programme, content and methodology, teaching the course under the name of "Initial Teacher Training Course within the framework of the European Higher Education Area". Continuous Training means learning throughout one's life as an Engineering teacher. They are actions designed to update and improve teaching staff, and are systematically offered on the current issues of: Teaching Strategies, training for research, training for personal development, classroom innovations, etc. They are activities aimed at conceptual change, changing the way of teaching and bringing teaching staff up-to-date. At the same time, the Institution is at the disposal of all teaching staff as a meeting point to discuss issues in common, attend conferences, department meetings, etc. In this Congress we present a justification of both training models and their design together with some results obtained on: training needs, participation, how it is developing and to what extent students are profiting from it.

González-Tirados, R. M.

2009-04-01

280

Developing robotic behavior using a genetic programming model  

SciTech Connect

This report describes the methodology for using a genetic programming model to develop tracking behaviors for autonomous, microscale robotic vehicles. The use of such vehicles for surveillance and detection operations has become increasingly important in defense and humanitarian applications. Through an evolutionary process similar to that found in nature, the genetic programming model generates a computer program that when downloaded onto a robotic vehicle`s on-board computer will guide the robot to successfully accomplish its task. Simulations of multiple robots engaged in problem-solving tasks have demonstrated cooperative behaviors. This report also discusses the behavior model produced by genetic programming and presents some results achieved during the study.

Pryor, R.J. [Sandia National Labs., Albuquerque, NM (United States). Program Management Dept.

1998-01-01

281

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

282

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

283

Rocketdyne/Westinghouse nuclear thermal rocket engine modeling  

NASA Astrophysics Data System (ADS)

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; and nuclear thermal rocket modeling directions.

Glass, James F.

284

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

285

Rocketdyne/Westinghouse nuclear thermal rocket engine modeling  

NASA Technical Reports Server (NTRS)

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; and nuclear thermal rocket modeling directions.

Glass, James F.

1993-01-01

286

Component-specific modeling. [jet engine hot section components  

NASA Technical Reports Server (NTRS)

Accomplishments are described for a 3 year program to develop methodology for component-specific modeling of aircraft hot section components (turbine blades, turbine vanes, and burner liners). These accomplishments include: (1) engine thermodynamic and mission models, (2) geometry model generators, (3) remeshing, (4) specialty three-dimensional inelastic structural analysis, (5) computationally efficient solvers, (6) adaptive solution strategies, (7) engine performance parameters/component response variables decomposition and synthesis, (8) integrated software architecture and development, and (9) validation cases for software developed.

Mcknight, R. L.; Maffeo, R. J.; Tipton, M. T.; Weber, G.

1992-01-01

287

Materials Science and Engineering A 472 (2008) 242250 Shear behavior of aluminum lattice truss sandwich panel structures  

E-print Network

Materials Science and Engineering A 472 (2008) 242­250 Shear behavior of aluminum lattice truss of Materials Science and Engineering, University of Virginia, 140 Chemistry Way, Charlottesville, VI 22904, USA hardenable 6061 aluminum tetrahedral lattice truss core sandwich panels have been fabricated by folding

Wadley, Haydn

2008-01-01

288

Hierarchical representation and machine learning from faulty jet engine behavioral examples to detect real time abnormal conditions  

Microsoft Academic Search

Jet engine behavior can be described by four major engine parameters and by their temporal and qualitative relationships. These parameters are rotational speeds of the low and high pressure turbine assemblies referred to as N1 and N2 respectively, exhaust gas temperature EGT, and combustion temperature COMBT. Normally, these parameters show stable readings. Faulty conditions like fuel interruption or bearing loss

U. K. Gupta; Moonis Ali

1988-01-01

289

ENGINEERING NEUTRON DIFFRACTION INSTRUMENTS AT HFIR AND SNS AND THEIR APPLICATION TO STUDIES OF THE BEHAVIOR OF STRUCTURAL  

E-print Network

ENGINEERING NEUTRON DIFFRACTION INSTRUMENTS AT HFIR AND SNS AND THEIR APPLICATION TO STUDIES OF THE BEHAVIOR OF STRUCTURAL MATERIALS Camden R. Hubbard Oak Ridge National Laboratory, P. O. Box 2008, Oak Ridge in physics, chemistry, materials science, engineering and biology. Fifteen new instruments are being

Pennycook, Steve

290

Modeling potentiometric titration behavior of glauconite  

Microsoft Academic Search

Potentiometric titration behavior and the effects of dissolution on the titration experiment of a complex natural clay mineral, glauconite, were investigated and interpreted according to surface complexation theory. Considerable dissolution was detected in the time frame of the titration experiments, with the amount of individual cations released from glauconite a function of solution variables and dissolution kinetics. Dissolution effects can

Weiping Lu; Edward H. Smith

1996-01-01

291

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

292

An Efficient Model-based Diagnosis Engine for Hybrid Systems Using Structural Model Decomposition  

NASA Technical Reports Server (NTRS)

Complex hybrid systems are present in a large range of engineering applications, like mechanical systems, electrical circuits, or embedded computation systems. The behavior of these systems is made up of continuous and discrete event dynamics that increase the difficulties for accurate and timely online fault diagnosis. The Hybrid Diagnosis Engine (HyDE) offers flexibility to the diagnosis application designer to choose the modeling paradigm and the reasoning algorithms. The HyDE architecture supports the use of multiple modeling paradigms at the component and system level. However, HyDE faces some problems regarding performance in terms of complexity and time. Our focus in this paper is on developing efficient model-based methodologies for online fault diagnosis in complex hybrid systems. To do this, we propose a diagnosis framework where structural model decomposition is integrated within the HyDE diagnosis framework to reduce the computational complexity associated with the fault diagnosis of hybrid systems. As a case study, we apply our approach to a diagnostic testbed, the Advanced Diagnostics and Prognostics Testbed (ADAPT), using real data.

Bregon, Anibal; Narasimhan, Sriram; Roychoudhury, Indranil; Daigle, Matthew; Pulido, Belarmino

2013-01-01

293

Toward a Gene Regulatory Network Model for Evolving Chemotaxis Behavior  

E-print Network

] is a computational model of bacterial growth and evolution, predicated on phenomena known to occur in bacterial cells-following behavior resembling bacterial chemotaxis. Under the conditions defined in this paper, an overwhelming of repellent. As bacterial behavior is heavily influenced by external environmental conditions (including other

Yao, Xin

294

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

295

Bingeing rats: A model of intermittent excessive behavior?  

Microsoft Academic Search

Intermittent excessive behaviors (IEB) characterize a variety human disorders including binge eating, drug abuse, alcoholism, aberrant sexual conduct, and compulsive gambling. Clinical co-morbidity exists among IEB, and limited treatment options are available. The use of behavioral models of bingeing and other feeding protocols is beginning to clarify neural similarities and differences that exist between IEB directed toward obtaining and consuming

Rebecca L. Corwin

2006-01-01

296

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

297

76 FR 8321 - Special Conditions: Pratt and Whitney Canada Model PW210S Turboshaft Engine  

Federal Register 2010, 2011, 2012, 2013, 2014

...Pratt and Whitney Canada Model PW210S Turboshaft Engine AGENCY: Federal Aviation Administration (FAA...and Whitney Canada (PWC) model PW210S turboshaft engine. This engine model will have a novel or unusual design feature...

2011-02-14

298

76 FR 33981 - Special Conditions: Pratt and Whitney Canada Model PW210S Turboshaft Engine  

Federal Register 2010, 2011, 2012, 2013, 2014

...Pratt and Whitney Canada Model PW210S Turboshaft Engine AGENCY: Federal Aviation Administration (FAA...issued for Pratt and Whitney Canada (PWC) model PW210S engines. The engine model will have a novel or unusual design feature...

2011-06-10

299

The interpersonal process model of demand/withdraw behavior.  

PubMed

The demand/withdraw interaction pattern is a destructive cycle of relationship communication behavior that is associated with negative individual and relationship outcomes. Demand/withdraw behavior is thought to be strongly linked to partners' emotional reactions, but current theories are inconsistent with empirical findings. The current study proposes the interpersonal process model of demand/withdraw behavior, which includes linkages between each partners' emotional reactions and the interpersonal behavior of demanding and withdrawing. Data come from problem solving discussions of 55 German couples with observationally coded demand/withdraw behavior and fundamental frequency (f?) to measure vocally encoded emotional arousal. Actor-partner interdependence models (Kenny, Kashy, & Cook, 2006) were used to examine associations among demand/withdraw behavior and f? in the overall discussion and 5-min segments. Significant cross-partner associations emerged for demanding and withdrawing behavior across the whole conversation as well as within 5-min segments, and these associations are partially accounted for by each individual's f?. When behaviorally coded demanders expressed more vocal arousal, they demanded more and withdrew less while their partners withdrew more. In contrast, when behaviorally coded withdrawers expressed more vocal arousal, their partners demanded less and withdrew more. Findings demonstrate that demand/withdraw behavior varies between couples (i.e., some couples engage in a stronger demand/withdraw cycle than others) and between segments (i.e., when 1 partner increases demanding, the other increases withdrawing). Findings support key elements of the interpersonal process model, showing intra- and interpersonal pathways linking demand/withdraw behavior and emotion and demonstrate the importance of partners' behavioral roles in these linkages. (PsycINFO Database Record (c) 2015 APA, all rights reserved). PMID:25495639

Baucom, Brian R; Dickenson, Janna A; Atkins, David C; Baucom, Donald H; Fischer, Melanie S; Weusthoff, Sarah; Hahlweg, Kurt; Zimmermann, Tanja

2015-02-01

300

Engineering the evolution of self-organizing behaviors in swarm robotics: a case study.  

PubMed

Evolutionary robotics (ER) is a powerful approach for the automatic synthesis of robot controllers, as it requires little a priori knowledge about the problem to be solved in order to obtain good solutions. This is particularly true for collective and swarm robotics, in which the desired behavior of the group is an indirect result of the control and communication rules followed by each individual. However, the experimenter must make several arbitrary choices in setting up the evolutionary process, in order to define the correct selective pressures that can lead to the desired results. In some cases, only a deep understanding of the obtained results can point to the critical aspects that constrain the system, which can be later modified in order to re-engineer the evolutionary process towards better solutions. In this article, we discuss the problem of engineering the evolutionary machinery that can lead to the desired result in the swarm robotics context. We also present a case study about self-organizing synchronization in a swarm of robots, in which some arbitrarily chosen properties of the communication system hinder the scalability of the behavior to large groups. We show that by modifying the communication system, artificial evolution can synthesize behaviors that scale properly with the group size. PMID:21554112

Trianni, Vito; Nolfi, Stefano

2011-01-01

301

Anomia treatment platform as behavioral engine for use in research on physiological adjuvants to neurorehabilitation.  

PubMed

The purpose of this study was to create a "behavioral treatment engine" for future use in research on physiological adjuvants in aphasia rehabilitation. We chose the behavioral target anomia, which is a feature displayed by many persons who have aphasia. Further, we wished to saturate the treatment approach with many strategies and cues that have been empirically reported to have a positive influence on aphasia outcome, with the goal being to optimize the potential for positive response in most participants. A single-subject multiple baseline design with replication across eight participants was employed. Four men and four women, with an average age of 62 yr and an average of 63.13 mo poststroke onset, served as participants. Word-retrieval treatment was administered 3 d/wk, 1 h/d for a total of 20 treatment hours (6-7 wk). Positive acquisition effects were evident in all eight participants (d effect size [ES] = 5.40). Treatment effects were maintained 3 mo after treatment termination for five participants (d ES = 2.94). Within and across semantic category, generalization was minimal (d ES = 0.43 within and 1.09 across). This study demonstrates that this behavioral treatment engine provides a solid platform on which to base future studies whereby various treatment conditions are manipulated and pharmacologic support is added. PMID:25019662

Kendall, Diane; Raymer, Anastasia; Rose, Miranda; Gilbert, JoEllen; Gonzalez Rothi, Leslie J

2014-01-01

302

From transformation traces to transformation rules: Assisting Model Driven Engineering  

E-print Network

From transformation traces to transformation rules: Assisting Model Driven Engineering approach. In this paper we are interested in semi-automatically gen- erating labelled graph (model) transformations conform to a particu- lar syntax (meta-model). Those transformations are basic operations in model driven

Paris-Sud XI, Université de

303

Using Critiquing Systems for Inconsistency Detection in Software Engineering Models  

Microsoft Academic Search

Many approaches have been proposed for consistency management of software engineering documents and specifications. A few others have been proposed to check consistency among software engineering models. For example, abstract state machines, knowledge-based approaches and so on. In this paper, we apply a different technique that uses critiquing systems. A critiquing system monitors user's actions and triggers a signal when

304

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

305

Variational Design in Electrical Engineering An Extension of Parametric Modeling  

E-print Network

). In this engineering domain the technology of variational design will release a tremendous potential of cost and time manner. After that, the technology of parametric driven modules for variational design in the contextVariational Design in Electrical Engineering An Extension of Parametric Modeling Dieter Roller

306

Enabler 1 and 2 engine system design modeling and comparisons  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

307

5. Historic photo of scale model of rocket engine test ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Historic photo of scale model of rocket engine test facility, June 18, 1957. On file at NASA Plumbrook Research Center, Sandusky, Ohio. NASA GRC photo number C-45264. - Rocket Engine Testing Facility, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

308

Experimental Model for Stimulating Creative Problem Solving by Engineering Students.  

ERIC Educational Resources Information Center

A heuristic model designed to improve creative problem-solving by engineering students was studied. Ten students majoring in industrial engineering were pre-tested to establish the range and accuracy of their performance prior to training and to identify stereotyped thinking. The test was an adventure scenario with 50 embedded problems along with…

Hayes, Harold L.

309

Modelling and control of internal combustion engines using intelligent techniques  

Microsoft Academic Search

This article will compare two different fuzzy-derived techniques for controlling small internal combustion engine and modeling fuel spray penetration in the cylinder of a diesel internal combustion engine. The first case study is implemented using conventional fuzzy-based paradigm, where human expertise and operator knowledge were used to select the parameters for the system. The second case study used an adaptive

S. H. Lee; R. J. Howlett; S. D. Walters; C. Crua

2007-01-01

310

Modeling and control of internal combustion engines using intelligent techniques  

Microsoft Academic Search

This article will compare two different fuzzy-derived techniques for controlling small internal combustion engine and modeling fuel spray penetration in the cylinder of a diesel internal combustion engine. The first case study is implemented using conventional fuzzy-based paradigm, where human expertise and operator knowledge were used to select the parameters for the system. The second case study used an adaptive

Shaun H. Lee; Robert J. Howlett; Simon D. Walters; Cyril Crua

2007-01-01

311

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

312

Requirements Engineering Meets Trust Management: Model, Methodology, and Reasoning  

Microsoft Academic Search

The last years have seen a number of proposals to incorporate Security Engineering into mainstream Software Requirements Engineering. How- ever, capturing trust and security requirements at an organizational level (as opposed to a design level) is still an open problem. This paper presents a formal framework for modeling and analyzing security and trust requirements. It extends the Tropos methodology, an

Paolo Giorgini; Fabio Massacci; John Mylopoulos; Nicola Zannone

2004-01-01

313

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

2008-04-01

314

Human Performance Models of Pilot Behavior  

NASA Technical Reports Server (NTRS)

Five modeling teams from industry and academia were chosen by the NASA Aviation Safety and Security Program to develop human performance models (HPM) of pilots performing taxi operations and runway instrument approaches with and without advanced displays. One representative from each team will serve as a panelist to discuss their team s model architecture, augmentations and advancements to HPMs, and aviation-safety related lessons learned. Panelists will discuss how modeling results are influenced by a model s architecture and structure, the role of the external environment, specific modeling advances and future directions and challenges for human performance modeling in aviation.

Foyle, David C.; Hooey, Becky L.; Byrne, Michael D.; Deutsch, Stephen; Lebiere, Christian; Leiden, Ken; Wickens, Christopher D.; Corker, Kevin M.

2005-01-01

315

A simple generative model of collective online behavior  

PubMed Central

Human activities increasingly take place in online environments, providing novel opportunities for relating individual behaviors to population-level outcomes. In this paper, we introduce a simple generative model for the collective behavior of millions of social networking site users who are deciding between different software applications. Our model incorporates two distinct mechanisms: one is associated with recent decisions of users, and the other reflects the cumulative popularity of each application. Importantly, although various combinations of the two mechanisms yield long-time behavior that is consistent with data, the only models that reproduce the observed temporal dynamics are those that strongly emphasize the recent popularity of applications over their cumulative popularity. This demonstrates—even when using purely observational data without experimental design—that temporal data-driven modeling can effectively distinguish between competing microscopic mechanisms, allowing us to uncover previously unidentified aspects of collective online behavior. PMID:25002470

Gleeson, James P.; Cellai, Davide; Onnela, Jukka-Pekka; Porter, Mason A.; Reed-Tsochas, Felix

2014-01-01

316

A simple generative model of collective online behavior.  

PubMed

Human activities increasingly take place in online environments, providing novel opportunities for relating individual behaviors to population-level outcomes. In this paper, we introduce a simple generative model for the collective behavior of millions of social networking site users who are deciding between different software applications. Our model incorporates two distinct mechanisms: one is associated with recent decisions of users, and the other reflects the cumulative popularity of each application. Importantly, although various combinations of the two mechanisms yield long-time behavior that is consistent with data, the only models that reproduce the observed temporal dynamics are those that strongly emphasize the recent popularity of applications over their cumulative popularity. This demonstrates--even when using purely observational data without experimental design--that temporal data-driven modeling can effectively distinguish between competing microscopic mechanisms, allowing us to uncover previously unidentified aspects of collective online behavior. PMID:25002470

Gleeson, James P; Cellai, Davide; Onnela, Jukka-Pekka; Porter, Mason A; Reed-Tsochas, Felix

2014-07-22

317

Data-driven models for uncertainty and behavior  

E-print Network

The last decade has seen an explosion in the availability of data. In this thesis, we propose new techniques to leverage these data to tractably model uncertainty and behavior. Specifically, this thesis consists of three ...

Gupta, Vishal, Ph. D. Massachusetts Institute of Technology

2014-01-01

318

Iterative procedures for space shuttle main engine performance models  

NASA Technical Reports Server (NTRS)

Performance models of the Space Shuttle Main Engine (SSME) contain iterative strategies for determining approximate solutions to nonlinear equations reflecting fundamental mass, energy, and pressure balances within engine flow systems. Both univariate and multivariate Newton-Raphson algorithms are employed in the current version of the engine Test Information Program (TIP). Computational efficiency and reliability of these procedures is examined. A modified trust region form of the multivariate Newton-Raphson method is implemented and shown to be superior for off nominal engine performance predictions. A heuristic form of Broyden's Rank One method is also tested and favorable results based on this algorithm are presented.

Santi, L. Michael

1989-01-01

319

Relevance of behavioral and social models to the study of consumer energy decision making and behavior  

SciTech Connect

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 aspects of the decision process, use different theoretical bases and approaches, and have been aimed at different audiences. Three major areas of discussion were selected: (1) models of adaptation to social change, (2) decision making and choice, and (3) diffusion of innovation. Within these three areas, the contributions of psychologists, sociologists, economists, marketing researchers, and others were reviewed. Five primary components of the models were identified and compared. The components are: (1) situational characteristics, (2) product characteristics, (3) individual characteristics, (4) social influences, and (5) the interaction or decision rules. The explicit use of behavioral and social science models in energy decision-making and behavior studies has been limited. Examples are given of a small number of energy studies which applied and tested existing models in studying the adoption of energy conservation behaviors and technologies, and solar technology.

Burns, B.A.

1980-11-01

320

Asymptotic behavior of the magnetization for the perceptron model  

E-print Network

Asymptotic behavior of the magnetization for the perceptron model Comportement limite de la magn´etisation pour le mod`ele du perceptron by David M´arquez-Carreras1 , Carles Rovira2 and Samy Tindel3 1 of a perceptron model for which the number of outputs is a small proportion of the size of the system

Tindel, Samy - Institut de Mathématiques �lie Cartan, Université Henri Poincaré

321

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

322

Hierarchical Modeling of Sequential Behavioral Data: Examining Complex Association Patterns in Mediation Models  

ERIC Educational Resources Information Center

This article presents new methods for modeling the strength of association between multiple behaviors in a behavioral sequence, particularly those involving substantively important interaction patterns. Modeling and identifying such interaction patterns becomes more complex when behaviors are assigned to more than two categories, as is the case…

Dagne, Getachew A.; Brown, C. Hendricks; Howe, George W.

2007-01-01

323

Engineered Barrier System: Physical and Chemical Environment Model  

SciTech Connect

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

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

2004-02-09

324

Comparing Learning Techniques for Hidden Markov Models of Human Supervisory Control Behavior  

E-print Network

Models of human behaviors have been built using many different frameworks. In this paper, we make use of Hidden Markov Models (HMMs) applied to human supervisory control behaviors. More specifically, we model the behavior ...

Cummings, M. L.

325

Modeling techniques for simulating well behavior  

E-print Network

to model the combined effect of wellbore storage and skin in pressure-transient test are developed. These relations enable this effect to be modeled in any conventional reservoir simulator without the need to modify the existing program. Alternative grid...

Rattu, Bungen Christina

2002-01-01

326

Comparison of free-piston Stirling engine model predictions with RE1000 engine test data  

NASA Technical Reports Server (NTRS)

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 Energy's Oak Ridge National Laboratory and NASA-Lewis. A kinematic code developed at Lewis was upgraded to permit simulation of free-piston engine performance; it was further upgraded and modified at Lewis and is currently being validated. The model predicts engine performance by numerical integration of equations for each control volume in the working space. Piston motions are determined by numerical integration of the force balance on each piston or can be specified as Fourier series. In addition, the model Fourier analyzes the various piston forces to permit the construction of phasor force diagrams. The paper compares predicted and experimental values of power and efficiency and shows phasor force diagrams for the RE1000 engine displacer and piston. Further development plans for the model are also discussed.

Tew, R. C.

1984-01-01

327

Modeling and simulating human teamwork behaviors using intelligent agents  

NASA Astrophysics Data System (ADS)

Among researchers in multi-agent systems there has been growing interest in using intelligent agents to model and simulate human teamwork behaviors. Teamwork modeling is important for training humans in gaining collaborative skills, for supporting humans in making critical decisions by proactively gathering, fusing, and sharing information, and for building coherent teams with both humans and agents working effectively on intelligence-intensive problems. Teamwork modeling is also challenging because the research has spanned diverse disciplines from business management to cognitive science, human discourse, and distributed artificial intelligence. This article presents an extensive, but not exhaustive, list of work in the field, where the taxonomy is organized along two main dimensions: team social structure and social behaviors. Along the dimension of social structure, we consider agent-only teams and mixed human-agent teams. Along the dimension of social behaviors, we consider collaborative behaviors, communicative behaviors, helping behaviors, and the underpinning of effective teamwork-shared mental models. The contribution of this article is that it presents an organizational framework for analyzing a variety of teamwork simulation systems and for further studying simulated teamwork behaviors.

Fan, Xiaocong; Yen, John

2004-12-01

328

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

329

The Sikorsky Twin Engined Amphibian, Type S-38, Model 1928  

NASA Technical Reports Server (NTRS)

The S-38, model 28 is a nine passenger Sesquiplane powered by two Pratt and Whitney Wasp 410 HP engines and is intended for routes where the ability to take off and land from both land and water is essential.

1928-01-01

330

Detecting mistakes in engineering models: the effects of experimental design  

E-print Network

This paper presents the results of an experiment with human subjects investigating their ability to discover a mistake in a model used for engineering design. For the purpose of this study, a known mistake was intentionally ...

Savoie, Troy B.

331

Integration of engineering models in computer-aided preliminary design  

E-print Network

The problems of the integration of engineering models in computer-aided preliminary design are reviewed. This paper details the research, development, and testing of modifications to Paper Airplane, a LISP-based computer ...

Lajoie, Ronnie M.

332

Evaluation of the Munich Method for modeling rocket engine performance  

NASA Technical Reports Server (NTRS)

A new procedure, dubbed the Munich Method, has been proposed recently for the modeling of rocket engine performance. The author of the Munich Method claims it to be an extension and improvement of the thermodynamic procedures used to model rocket engines in the NASA-Lewis chemical equilibrium program. An examination of the Munich Method shows that it contains several flaws. If these defects are corrected then the Munich Method will produce results identical to those generated by the NASA-Lewis Code.

Zeleznik, Frank J.

1993-01-01

333

Sound methods and effective tools for engineering modeling and analysis  

Microsoft Academic Search

Modeling and analysis is indispensable in engineering. To be safe and effective, a modeling method requires a language with a validated semantics; feature-rich, easy-to-use, dependable tools; and low engineering costs. Today we lack adequate means to develop such methods. We present a partial solution combining two techniques: formal methods for language design, and package-oriented programming for function and usability at

David Coppit; Kevin J. Sullivan

2003-01-01

334

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

335

Use of transport models for wildfire behavior simulations  

SciTech Connect

Investigators have attempted to describe the behavior of wildfires for over fifty years. Current models for numerical description are mainly algebraic and based on statistical or empirical ideas. The authors have developed a transport model called FIRETEC. The use of transport formulations connects the propagation rates to the full conservation equations for energy, momentum, species concentrations, mass, and turbulence. In this paper, highlights of the model formulation and results are described. The goal of the FIRETEC model is to describe most probable average behavior of wildfires in a wide variety of conditions. FIRETEC represents the essence of the combination of many small-scale processes without resolving each process in complete detail.

Linn, R.R.; Harlow, F.H.

1998-01-01

336

(Non)Issues of infinite regress in modeling motor behavior.  

PubMed

In the past, infinite regress criticisms that have been raised about models of motor behavior have been reserved for executive-type models (e.g., Beek & Meijer, 1988). On the basis of Gödel's (1930/1986) proof that an algorithm cannot prove its own validity, the authors reason that executive- as well as self-organized-type explanatory models of motor behavior have infinite regress difficulties. The conclusion offered in the present article is that judgments on a model's theoretical importance should be based not on issues of infinite regress but on other relevant characteristics, such as its propensity for falsification (Popper, 1959). PMID:20037024

Kohl, R M; Ben-David, H A

1998-03-01

337

GAS TURBINE ENGINE PERFORMANCE MODEL APPLICATIONS USING AN OBJECT ORIENTED SIMULATION TOOL  

Microsoft Academic Search

Engine performance models are used throughout the life cycle of an engine from conceptual design to testing, certification and maintenance. The objective of this paper is to demonstrate the use and advantages of an engine performance model, developed using an object-oriented simulation tool, for the following applications: É Building an engine model from existing engine components and running steady state

A. Alexiou; K. Mathioudakis

2006-01-01

338

The effect of a nematode parasite on feeding and dung-burying behavior of an ecosystem engineer.  

PubMed

Dung beetles (genus Phanaeus) consume feces in both their larval and adults forms and because of their unique dietary niche, and behaviors associated with the burial of feces, are considered ecosystem engineers. In addition, because these insects subsist on a diet composed exclusively of feces, it is likely they encounter parasitic propagules more frequently than other animals do. Parasites often alter their host's behavior, so we set out to test whether Physocephalus sexalatus (a cosmopolitan nematode parasite of ungulates) does so in ways that affect the dung beetle's role as an ecosystem engineer and/or its predator-prey relationships (transmission of the parasite). Classic tests of anti-predator behavior did not reveal behavioral differences based on the beetles' infection status. However, this parasite did alter the beetles' behaviors in ways that could be critical for its role in fecal processing and therefore ecosystem engineering. Infected beetles exhibited anorexic behavior and consumed only half the amount of feces ingested by similar uninfected beetles. Infected beetles also buried less feces and did so in tunnels that were significantly shorter than those created by uninfected beetles. Fecal burial is naturally beneficial because it aerates the soil, incorporates nitrogenous compounds, and increases the flow of water thereby making soil and pastureland more productive. We showed that the nematode parasite P. sexalatus itself becomes an ecosystem engineer as it modifies the behavior of its already influential intermediate host. PMID:24737785

Boze, Broox G V; Moore, Janice

2014-07-01

339

Transtheoretical model of health behavior change applied to voice therapy.  

PubMed

Studies of patient adherence to health behavior programs, such as physical exercise, smoking cessation, and diet, have resulted in the formulation and validation of the Transtheoretical Model (TTM) of behavior change. Although widely accepted as a guide for the development of health behavior interventions, this model has not been applied to vocal rehabilitation. Because resolution of vocal difficulties frequently depends on a patient's ability to make changes in vocal and health behaviors, the TTM may be a useful way to conceptualize voice behavior change processes, including the patient's readiness for change. The purpose of this paper is to apply the TTM to the voice therapy process to: (1) provide an organizing framework for understanding of behavior change in voice therapy, (2) explain how treatment adherence problems can arise, and (3) provide broad strategies to improve treatment adherence. Given the significant role of treatment adherence in treatment outcome, considering readiness for behavior change should be taken into account when planning treatment. Principles of health behavior change can aid speech pathologists in such understanding and estimating readiness for voice therapy. PMID:18082367

van Leer, Eva; Hapner, Edie R; Connor, Nadine P

2008-11-01

340

Transtheoretical Model of Health Behavior Change Applied to Voice Therapy  

PubMed Central

Summary Studies of patient adherence to health behavior programs, such as physical exercise, smoking cessation, and diet, have resulted in the formulation and validation of the Transtheoretical Model (TTM) of behavior change. Although widely accepted as a guide for the development of health behavior interventions, this model has not been applied to vocal rehabilitation. Because resolution of vocal difficulties frequently depends on a patient’s ability to make changes in vocal and health behaviors, the TTM may be a useful way to conceptualize voice behavior change processes, including the patient’s readiness for change. The purpose of this paper is to apply the TTM to the voice therapy process to: (1) provide an organizing framework for understanding of behavior change in voice therapy, (2) explain how treatment adherence problems can arise, and (3) provide broad strategies to improve treatment adherence. Given the significant role of treatment adherence in treatment outcome, considering readiness for behavior change should be taken into account when planning treatment. Principles of health behavior change can aid speech pathologists in such understanding and estimating readiness for voice therapy. PMID:18082367

van Leer, Eva; Hapner, Edie R.; Connor, Nadine P.

2010-01-01

341

Serotonergic pharmacology in animal models: from behavioral disorders to dyskinesia.  

PubMed

Serotonin (5-HT) dysfunction has been involved in both movement and behavioral disorders. Serotonin pharmacology improves dyskinetic movements as well as depressive, anxious, aggressive and anorexic symptoms. Animal models have been useful to investigate more precisely to what extent 5-HT is involved and whether drugs targeting the 5-HT system can counteract the symptoms exhibited. We review existing rodent and non-human primate (NHP) animal models in which selective 5-HT or dual 5-HT-norepinephrine (NE) transporter inhibitors, as well as specific 5-HT receptors agonists and antagonists, monoamine oxidase A inhibitors (IMAO-A) and MDMA (Ecstasy) have been used. We review overlaps between the various drug classes involved. We confront behavioral paradigms and treatment regimen. Some but not all animal models and associated pharmacological treatments have been extensively studied in the litterature. In particular, the impact of selective serotonin reuptake inhibitors (SSRI) has been extensively investigated using a variety of pharmacological or genetic rodent models of depression, anxiety, aggressiveness. But the validity of these rodent models is questioned. On the contrary, few studies did address the potential impact of targeting the 5-HT system on NHP models of behavioral disorders, despite the fact that those models may match more closely to human pathologies. Further investigations with carefull behavioral analysis will improve our understanding of neural bases underlying the pathophysiology of movement and behavioral disorders. PMID:24486710

Beaudoin-Gobert, Maude; Sgambato-Faure, Véronique

2014-06-01

342

A Behavioral Approach to Linear Exact Modeling  

Microsoft Academic Search

parameter-free framework for the study of the general problem of Absfract-The behvioral approach to system theory provides a linear exact modeling and recursive modeling. The main contri- bution of this paper is the solution of the (continuous-time) polynomial-exponential time series modeling problem. Both re- cursive and nonrecursive solutions are provided and classified according to properties like complexity and controllability. It

A. Ocen' iew

343

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

344

Engineering\\/economic end-use energy models  

Microsoft Academic Search

A brief review is presented on engineering\\/economic end-use energy models. End-use modeling is described within the broades context of an analytical framework giving statistically sound and valid forecasts. Some aspects of the end-use modeling problem, associated with technology and technology characterization are high-lighted. The results of policy application are given. (AIP)

Daniel M. Hamblin; Teresa A.. Vineyard

1985-01-01

345

Engineering-economic model of residential energy use  

Microsoft Academic Search

A comprehensive engineering-economic computer model used to simulate energy use in the residential sector from 1970 to 2000 is described. The model is to provide an analytical tool with which to evaluate a variety of conservation policies, technologies, and stragegies for their impacts on residential energy use and fuel expenditures over time. The present version of the model deals with

E. Hirst; W. Lin; J. Cope

1976-01-01

346

Engineering/economic end-use energy models  

NASA Astrophysics Data System (ADS)

A brief review is presented on engineering/economic end-use energy models. End-use modeling is described within the broades context of an analytical framework giving statistically sound and valid forecasts. Some aspects of the end-use modeling problem, associated with technology and technology characterization are high-lighted. The results of policy application are given. (AIP)

Hamblin, Daniel M.; Vineyard, Teresa A..

1985-11-01

347

Systems modeling at the Idaho National Engineering Laboratory  

NASA Astrophysics Data System (ADS)

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

Bray, Michael A.

1994-12-01

348

Analytical Model for Predicting Mechanotransduction Effects in Engineered Cardiac Tissue  

Microsoft Academic Search

Mechanochemical and mechanoelectrical signaling is imperative for cardiac organogenesis and un- derlies pathophysiological events. New techniques for engineering cardiac tissue allow unprecedented means of modeling these phenomena in vitro. However, experimental design is often hampered by a lack of models that can be adapted to the ideal conditions these methods allow. To address these deficiencies, we developed a mathematical model

David C. Latimer; Bradley J. Roth; Kevin Kit Parker

2003-01-01

349

Building a Bridge between Information Engineering and Model Driven Architecture  

Microsoft Academic Search

The Model Driven Architecture (MDA) approach of OMG aims to automat- ically derive software from models. Information Engineering (IE) is succeeding to do this with well established industry solutions for more then one decade. IE can be introduced into the MDA world using model transformation such that both of them can profit from each other in a cooperative way.

Xiaoxia Lin; Mustafa Arikan; Gerti Kappel

350

GOLD NANOROD PHOTOTHERMAL THERAPY IN A GENETICALLY ENGINEERED MOUSE MODEL  

E-print Network

GOLD NANOROD PHOTOTHERMAL THERAPY IN A GENETICALLY ENGINEERED MOUSE MODEL OF SOFT TISSUE SARCOMA and biology than subcutaneous xenograft models. Using polyethylene glycol (PEG)- coated gold nanorods (PEG in xenograft models and which may be of future clinical interest. Keywords: Gold nanorods; photothermal

Bhatia, Sangeeta

351

Synthesizing Client Load Models for Performance Engineering via Web Crawling  

E-print Network

Synthesizing Client Load Models for Performance Engineering via Web Crawling Yuhong Cai Dept on the use of loading tests based on a realistic client behaviour load model. Unfortunately developing such load models and associated test plans and scripts is tedious and error-prone with most existing web

Grundy, John

352

An engineering approach to the prediction of fatigue behavior of unnotched/notched fiber reinforced composite laminates  

NASA Technical Reports Server (NTRS)

An engineering approach is proposed for predicting unnotched/notched laminate fatigue behavior from basic lamina fatigue data. The fatigue analysis procedure was used to determine the laminate property (strength/stiffness) degradation as a function of fatigue cycles in uniaxial tension and in plane shear. These properties were then introduced into the failure model for a notched laminate to obtain damage growth, residual strength, and failure mode. The approach is thus essentially a combination of the cumulative damage accumulation (akin to the Miner-Palmgren hypothesis and its derivatives) and the damage growth rate (similar to the fracture mechanics approach) philosophies. An analysis/experiment correlation appears to confirm the basic postulates of material wearout and the predictability of laminate fatigue properties from lamina fatigue data.

Kulkarni, S. V.; Mclaughlin, P. V., Jr.

1978-01-01

353

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

354

Electromagnetic scattering from simple jet engine models  

Microsoft Academic Search

The mode-matching (MM) technique is employed for the evaluation of the radar cross section (RCS) of structures that simulate a jet engine inlet. The geometry consists of a perfectly conducting cylindrical inlet terminated by an array of blades mounted on a cylindrical hub. Comparisons of numerical results with actual measurements are presented for the first time

H. T. Anastassiu; J. L. Volakis; D. C. Ross; D. Andersh

1996-01-01

355

Modeling uncertainty in requirements engineering decision support  

NASA Technical Reports Server (NTRS)

One inherent characteristic of requrements engineering is a lack of certainty during this early phase of a project. Nevertheless, decisions about requirements must be made in spite of this uncertainty. Here we describe the context in which we are exploring this, and some initial work to support elicitation of uncertain requirements, and to deal with the combination of such information from multiple stakeholders.

Feather, Martin S.; Maynard-Zhang, Pedrito; Kiper, James D.

2005-01-01

356

Engine panel seals for hypersonic engine applications: High temperature leakage assessments and flow modelling  

NASA Technical Reports Server (NTRS)

A critical mechanical system in advanced hypersonic engines is the panel-edge seal system that seals gaps between the articulating horizontal engine panels and the adjacent engine splitter walls. Significant advancements in seal technology are required to meet the extreme demands placed on the seals, including the simultaneous requirements of low leakage, conformable, high temperature, high pressure, sliding operation. In this investigation, the seal concept design and development of two new seal classes that show promise of meeting these demands will be presented. These seals include the ceramic wafer seal and the braided ceramic rope seal. Presented are key elements of leakage flow models for each of these seal types. Flow models such as these help designers to predict performance-robbing parasitic losses past the seals, and estimate purge coolant flow rates. Comparisons are made between measured and predicted leakage rates over a wide range of engine simulated temperatures and pressures, showing good agreement.

Steinetz, Bruce M.; Mutharasan, Rajakkannu; Du, Guang-Wu; Miller, Jeffrey H.; Ko, Frank

1992-01-01

357

Modeling nonlinear behavior in a piezoelectric actuator  

Microsoft Academic Search

A piezoelectric tube actuator is employed as a sample positioning device in Nanocut, a cutting instrument conceived to study the mechanics of nanometric cutting. Extension of functionality of the instrument as a nanometric machine tool motivates the search for an accurate model of the actuator for implementing feedback control. A simple nonlinear model describing longitudinal expansion of the piezoelectric tube

H. Richter; E. A. Misawa; D. A. Lucca; H. Lu

2001-01-01

358

An experimental study on a model Stirling engine car  

SciTech Connect

A Stirling engine is a mechanical device that operates on a closed regenerative thermodynamic cycle, with cyclic compression and expansion of the working fluid at different temperature levels. The flow is controlled by volume changes, and there exists a net conversion of the heat to work. Stirling engines are ideally suited to off-grid electric power generation because of their multi-fuel capability, potentially high efficiency and low noise. The first model Stirling Techno-rally was held in August 1997 for further promotion of the clean and quiet Stirling engine as one of the Centennial Anniversary events of JSME. In the race, more than one hundred cars competed for the time on a course of 13 meters length and 30 centimeters width. In Ashikaga Institute of Technology, a model Stirling engine car Ashikaga Gekkoh was made for this event. In this paper the authors report on this model car that won the championship of the Stirling Techno-rally.

Sohma, Yutaka; Wu, Chungming; Isshiki, Seita; Ushiyama, Izumi

1999-07-01

359

Modeling the Behavior of Heat-Shrinkable Thin Films  

Microsoft Academic Search

We describe an asymptotic model for the behavior of PET-like heat-shrinkable thin films that includes both membrane and bending\\u000a energies when the thickness of the film is positive. We compare the model to Koiter’s shell model and to models in which a\\u000a membrane energy or a bending energy are obtained by ?-convergence techniques. We also provide computational results for various

Pavel B?lík; Bob Jennings; Mikhail M. Shvartsman; Cristina U. Thomas

2009-01-01

360

Nuclear Graphite - Fracture Behavior and Modeling  

SciTech Connect

Evidence for the graphite fracture mechanism is reviewed and discussed. The roles of certain microstructural features in the graphite fracture process are reported. The Burchell fracture model is described and its derivation reported. The successful application of the fracture model to uniaxial tensile data from several graphites with widely ranging structure and texture is reported. The extension of the model to multiaxial loading scenarios using two criteria is discussed. Initially, multiaxial strength data for H-451 graphite were modeled using the fracture model and the Principle of Independent Action. The predicted 4th stress quadrant failure envelope was satisfactory but the 1st quadrant predictions were not conservative and thus were unsatisfactory. Multiaxial strength data from the 1st and 4th stress quadrant for NBG-18 graphite are reported. To improve the conservatism of the predicted 1st quadrant failure envelope for NBG-18 the Shetty criterion has been applied to obtain the equivalent critical stress intensity factor, KIc (Equi), for each applied biaxial stress ratio. The equivalent KIc value is used in the Burchell fracture model to predict the failure envelope. The predicted 1st stress quadrant failure envelope is conservative and thus more satisfactory than achieved previously using the fracture model combined with the Principle of Independent Action.

Burchell, Timothy D [ORNL; Battiste, Rick [ORNL; Strizak, Joe P [ORNL

2011-01-01

361

Modeling of Particulate Behavior in Pinhole Breaches  

SciTech Connect

A model is presented for calculating depressurization time for and particulate release from used nuclear fuel dry storage containers that have developed a pinhole breach. Particular attention is given to particulate deposition and transmission within the breach pathway. The model is modular in nature and is developed in a way that allows for more advanced treatments of internal temperature, internal component geometry, or aerosol flow to be readily incorporated. The model can be treated as a basis for addressing concerns associated with monitoring and verification efforts during long-term dry cask storage

Casella, Andrew M.; Loyalka, Sudarshan K.; Hanson, Brady D.

2014-04-01

362

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

363

Modeling choice behavior for new pharmaceutical products.  

PubMed

This paper presents a dynamic generalization of a model often used to aid marketing decisions relating to conventional products. The model uses stated-preference data in a random-utility framework to predict adoption rates for new pharmaceutical products. In addition, this paper employs a Markov model of patient learning in drug selection. While the simple learning rule presented here is only a rough approximation to reality, this model nevertheless systematically incorporates important features including learning and the influence of shifting preferences on market share. Despite its simplifications, the integrated framework of random-utility and product attribute updating presented here is capable of accommodating a variety of pharmaceutical marketing and development problems. This research demonstrates both the strengths of stated-preference market research and some of its shortcomings for pharmaceutical applications. PMID:11704970

Bingham, M F; Johnson, F R; Miller, D

2001-01-01

364

Mean Line Pump Flow Model in Rocket Engine System Simulation  

NASA Technical Reports Server (NTRS)

A mean line pump flow modeling method has been developed to provide a fast capability for modeling turbopumps of rocket engines. Based on this method, a mean line pump flow code PUMPA has been written that can predict the performance of pumps at off-design operating conditions, given the loss of the diffusion system at the design point. The pump code can model axial flow inducers, mixed-flow and centrifugal pumps. The code can model multistage pumps in series. The code features rapid input setup and computer run time, and is an effective analysis and conceptual design tool. The map generation capability of the code provides the map information needed for interfacing with a rocket engine system modeling code. The off-design and multistage modeling capabilities of the code permit parametric design space exploration of candidate pump configurations and provide pump performance data for engine system evaluation. The PUMPA code has been integrated with the Numerical Propulsion System Simulation (NPSS) code and an expander rocket engine system has been simulated. The mean line pump flow code runs as an integral part of the NPSS rocket engine system simulation and provides key pump performance information directly to the system model at all operating conditions.

Veres, Joseph P.; Lavelle, Thomas M.

2000-01-01

365

Continuous-valued probabilistic behavior in a VLSI generative model.  

PubMed

This paper presents the VLSI implementation of the continuous restricted Boltzmann machine (CRBM), a probabilistic generative model that is able to model continuous-valued data with a simple and hardware-amenable training algorithm. The full CRBM system consists of stochastic neurons whose continuous-valued probabilistic behavior is mediated by injected noise. Integrating on-chip training circuits, the full CRBM system provides a platform for exploring computation with continuous-valued probabilistic behavior in VLSI. The VLSI CRBM's ability both to model and to regenerate continuous-valued data distributions is examined and limitations on its performance are highlighted and discussed. PMID:16722178

Chen, Hsin; Fleury, Patrice C D; Murray, Alan F

2006-05-01

366

Complex Behavior in Simple Models of Biological Coevolution  

NASA Astrophysics Data System (ADS)

We explore the complex dynamical behavior of simple predator-prey models of biological coevolution that account for interspecific and intraspecific competition for resources, as well as adaptive foraging behavior. In long kinetic Monte Carlo simulations of these models we find quite robust 1/f-like noise in species diversity and population sizes, as well as power-law distributions for the lifetimes of individual species and the durations of quiet periods of relative evolutionary stasis. In one model, based on the Holling Type II functional response, adaptive foraging produces a metastable low-diversity phase and a stable high-diversity phase.

Rikvold, Per Arne

367

Creep-rupture behavior of candidate Stirling engine iron supperalloys in high-pressure hydrogen. Volume 2: Hydrogen creep-rupture behavior  

NASA Technical Reports Server (NTRS)

The creep rupture behavior of nine iron base and one cobalt base candidate Stirling engine alloys is evaluated. Rupture life, minimum creep rate, and time to 1% strain data are analyzed. The 3500 h rupture life stress and stress to obtain 1% strain in 3500 h are also estimated.

Bhattacharyya, S.; Peterman, W.; Hales, C.

1984-01-01

368

A Neurobehavioral Model of Flexible Spatial Language Behaviors  

PubMed Central

We propose a neural dynamic model that specifies how low-level visual processes can be integrated with higher level cognition to achieve flexible spatial language behaviors. This model uses real-word visual input that is linked to relational spatial descriptions through a neural mechanism for reference frame transformations. We demonstrate that the system can extract spatial relations from visual scenes, select items based on relational spatial descriptions, and perform reference object selection in a single unified architecture. We further show that the performance of the system is consistent with behavioral data in humans by simulating results from 2 independent empirical studies, 1 spatial term rating task and 1 study of reference object selection behavior. The architecture we present thereby achieves a high degree of task flexibility under realistic stimulus conditions. At the same time, it also provides a detailed neural grounding for complex behavioral and cognitive processes. PMID:21517224

Lipinski, John; Schneegans, Sebastian; Sandamirskaya, Yulia; Spencer, John P.; Schöner, Gregor

2012-01-01

369

Modeling Pedestrian's Conformity Violation Behavior: A Complex Network Based Approach  

PubMed Central

Pedestrian injuries and fatalities present a problem all over the world. Pedestrian conformity violation behaviors, which lead to many pedestrian crashes, are common phenomena at the signalized intersections in China. The concepts and metrics of complex networks are applied to analyze the structural characteristics and evolution rules of pedestrian network about the conformity violation crossings. First, a network of pedestrians crossing the street is established, and the network's degree distributions are analyzed. Then, by using the basic idea of SI model, a spreading model of pedestrian illegal crossing behavior is proposed. Finally, through simulation analysis, pedestrian's illegal crossing behavior trends are obtained in different network structures and different spreading rates. Some conclusions are drawn: as the waiting time increases, more pedestrians will join in the violation crossing once a pedestrian crosses on red firstly. And pedestrian's conformity violation behavior will increase as the spreading rate increases. PMID:25530755

Zhou, Zhuping; Hu, Qizhou; Wang, Wei

2014-01-01

370

Modeling pedestrian's conformity violation behavior: a complex network based approach.  

PubMed

Pedestrian injuries and fatalities present a problem all over the world. Pedestrian conformity violation behaviors, which lead to many pedestrian crashes, are common phenomena at the signalized intersections in China. The concepts and metrics of complex networks are applied to analyze the structural characteristics and evolution rules of pedestrian network about the conformity violation crossings. First, a network of pedestrians crossing the street is established, and the network's degree distributions are analyzed. Then, by using the basic idea of SI model, a spreading model of pedestrian illegal crossing behavior is proposed. Finally, through simulation analysis, pedestrian's illegal crossing behavior trends are obtained in different network structures and different spreading rates. Some conclusions are drawn: as the waiting time increases, more pedestrians will join in the violation crossing once a pedestrian crosses on red firstly. And pedestrian's conformity violation behavior will increase as the spreading rate increases. PMID:25530755

Zhou, Zhuping; Hu, Qizhou; Wang, Wei

2014-01-01

371

Modeling Weather Conditions Consequences on Road Trafficking Behaviors  

E-print Network

1 Modeling Weather Conditions Consequences on Road Trafficking Behaviors Guillaume Allain´ematiques de Toulouse Abstract--We provide a model to understand how adverse weather conditions modify traffic network and provides accurate unbiased forecasted speed using live or short term forecasted weather data

Paris-Sud XI, Université de

372

BEHAVIOR OF A SAND RIDGE MODEL Juan Mario Restrepo  

E-print Network

BEHAVIOR OF A SAND RIDGE MODEL Juan Mario Restrepo Mathematics Department University of California, Los Angeles Los Angeles, CA 90095 Abstract. A model for the formation and evolution of longshore sand waves, which are represented by wave packets, and a sandy bottom topography, conspire to produce sand

Soatto, Stefano

373

Routine Based Models of Anticipation in Natural Behaviors  

Microsoft Academic Search

This paper describes the analysis and modeling of nat- ural human behaviors on top of a routine based model of cognition. This theory hypothesizes that there ex- ists in the brain a collection of built-in programs, which are coded with a x ed set of basic visual primitives and can be reprogrammed to carry out various visual tasks. Despite the

Weilie Yi; Dana H. Ballard

374

Modeling and simulating human teamwork behaviors using intelligent agents  

Microsoft Academic Search

Among researchers in multi-agent systems there has been growing interest in using intelligent agents to model and simulate human teamwork behaviors. Teamwork modeling is important for training humans in gaining collaborative skills, for supporting humans in making critical decisions by proactively gathering, fusing, and sharing information, and for building coherent teams with both humans and agents working effectively on intelligence-intensive

Xiaocong Fan; John Yen

2004-01-01

375

Animal behavior models of the mechanisms underlying antipsychotic atypicality  

Microsoft Academic Search

This review describes the animal behavior models that provide insight into the mechanisms underlying the critical differences between the actions of typical vs. atypical antipsychotic drugs. Although many of these models are capable of differentiating between antipsychotic and other psychotropic drugs, only a few seem to be able to differentiate between typical and atypical antipsychotics, such as the paw test

Mark A. Geyer; Bart Ellenbroek

2003-01-01

376

Integrating sensorimotor systems in a robot model of cricket behavior  

Microsoft Academic Search

The mechanisms by which animals manage sensorimotor integration and coordination of different behaviors can be investigated in robot models. In previous work the first author has built a robot that localizes sound based on close modeling of the auditory and neural system in the cricket. It is known that the cricket combines its response to sound with other sensorimotor activities

Barbara H. Webb; Reid R. Harisson

2000-01-01

377

Integrating sensorimotor systems in a robot model of cricket behavior  

Microsoft Academic Search

The mechanisms by which animals manage sensorimotor integration and coordination of different behaviors can be investigated in robot models. In previous work the first author has build a robot that localizes sound based on close modeling of the auditory and neural system in the cricket. It is known that the cricket combines its response to sound with other sensorimotor activities

Barbara H. Webb; Reid R. Harrison

2000-01-01

378

Asymptotic behavior of the magnetization for the perceptron model  

E-print Network

Asymptotic behavior of the magnetization for the perceptron model Comportement limite de la magn#19;etisation pour le mod#18;ele du perceptron by David M#19;arquez-Carreras 1 , Carles Rovira 2 and Samy Tindel: In this paper, we show that, in case of a perceptron model for which the number of outputs is a small proportion

Henri Poincaré -Nancy-Université, Université

379

Behavior-based modeling and its application to Email analysis  

Microsoft Academic Search

The Email Mining Toolkit (EMT) is a data mining system that computes behavior profiles or models of user email accounts. These models may be used for a multitude of tasks including forensic analyses and detection tasks of value to law enforcement and intelligence agencies, as well as other typical tasks such as virus and spam detection. To demonstrate the power

Salvatore J. Stolfo; Shlomo Hershkop; Chia-wei Hu; Wei-jen Li; Olivier Nimeskern; Ke Wang

2006-01-01

380

Combining building and behavior models for evacuation planning.  

PubMed

To help users find optimal rescue and evacuation routes, this approach uses the extended hierarchical node relation model (EHI-NRM) to represent a building's internal structure. The approach also employs the improved cellular-automata model (ICA) to consider route-choice behavior, such as spatial reasoning and communication among evacuees. PMID:24808091

Yanhui Wang; Liqiang Zhang; Jingtao Ma; Liu Liu; Dongqin You; Lixin Zhang

2011-01-01

381

Modeling and Reasoning about Service Behaviors and their Compositions  

E-print Network

of advertising their capabilities to the entities that will use them, and service- oriented modeling should cater by the resource-aware timed behavioral language REMES, which we extend with service-specific infor- mation. Assuming a Hoare-triple model of service cor- rectness, we show how to check it by using the strongest

Becker, Steffen

382

A Neurobehavioral Model of Flexible Spatial Language Behaviors  

ERIC Educational Resources Information Center

We propose a neural dynamic model that specifies how low-level visual processes can be integrated with higher level cognition to achieve flexible spatial language behaviors. This model uses real-word visual input that is linked to relational spatial descriptions through a neural mechanism for reference frame transformations. We demonstrate that…

Lipinski, John; Schneegans, Sebastian; Sandamirskaya, Yulia; Spencer, John P.; Schoner, Gregor

2012-01-01

383

An Extended Combustion Model for the Aircraft Turbojet Engine  

NASA Astrophysics Data System (ADS)

The paper consists in modelling and simulation of the combustion in a turbojet engine in order to find optimal characteristics of the burning process and the optimal shape of combustion chambers. The main focus of this paper is to find a new configuration of the aircraft engine combustion chambers, namely an engine with two main combustion chambers, one on the same position like in classical configuration, between compressor and turbine and the other, placed behind the turbine but not performing the role of the afterburning. This constructive solution could allow a lower engine rotational speed, a lower temperature in front of the first stage of the turbine and the possibility to increase the turbine pressure ratio by extracting the flow stream after turbine in the inner nozzle. Also, a higher thermodynamic cycle efficiency and thrust in comparison to traditional constant-pressure combustion gas turbine engines could be obtained.

Rotaru, Constantin; Andres-Mih?il?, Mihai; Matei, Pericle Gabriel

2014-08-01

384

Virtue ethics, positive psychology, and a new model of science and engineering ethics education.  

PubMed

This essay develops a new conceptual framework of science and engineering ethics education based on virtue ethics and positive psychology. Virtue ethicists and positive psychologists have argued that current rule-based moral philosophy, psychology, and education cannot effectively promote students' moral motivation for actual moral behavior and may even lead to negative outcomes, such as moral schizophrenia. They have suggested that their own theoretical framework of virtue ethics and positive psychology can contribute to the effective promotion of motivation for self-improvement by connecting the notion of morality and eudaimonic happiness. Thus this essay attempts to apply virtue ethics and positive psychology to science and engineering ethics education and to develop a new conceptual framework for more effective education. In addition to the conceptual-level work, this essay suggests two possible educational methods: moral modeling and involvement in actual moral activity in science and engineering ethics classes, based on the conceptual framework. PMID:24691813

Han, Hyemin

2015-04-01

385

Individual Differences and Behavioral Aspects Involved in Modeling Web Navigation  

Microsoft Academic Search

\\u000a This paper presents an empirical study aiming at investigating individual differences and behavioral aspects involved in modeling\\u000a web navigation. Factors that have an influence on web navigation behavior were identified with the aid of task analysis and\\u000a their relevance in predicting task outcomes (performance, satisfaction, disorientation) was tested with the aid of multiple\\u000a regression analysis. Several types of navigation metrics

Ion Juvina; Herre Van Oostendorp

2004-01-01

386

Modeling of Commercial Turbofan Engine With Ice Crystal Ingestion: Follow-On  

NASA Technical Reports Server (NTRS)

The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which is ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in flight. The computational tool was utilized to help guide a portion of the PSL testing, and was used to predict ice accretion could also occur at significantly lower altitudes. The predictions were qualitatively verified by subsequent testing of the engine in the PSL. In a previous study, analysis of select PSL test data points helped to calibrate the engine icing computational tool to assess the risk of ice accretion. This current study is a continuation of that data analysis effort. The study focused on tracking the variations in wet bulb temperature and ice particle melt ratio through the engine core flow path. The results from this study have identified trends, while also identifying gaps in understanding as to how the local wet bulb temperature and melt ratio affects the risk of ice accretion and subsequent engine behavior.

Jorgenson, Philip C. E.; Veres, Joseph P.; Coennen, Ryan

2014-01-01

387

Bayesian network model of crowd emotion and negative behavior  

NASA Astrophysics Data System (ADS)

The effects of overcrowding have become a major concern for event organizers. One aspect of this concern has been the idea that overcrowding can enhance the occurrence of serious incidents during events. As one of the largest Muslim religious gathering attended by pilgrims from all over the world, Hajj has become extremely overcrowded with many incidents being reported. The purpose of this study is to analyze the nature of human emotion and negative behavior resulting from overcrowding during Hajj events from data gathered in Malaysian Hajj Experience Survey in 2013. The sample comprised of 147 Malaysian pilgrims (70 males and 77 females). Utilizing a probabilistic model called Bayesian network, this paper models the dependence structure between different emotions and negative behaviors of pilgrims in the crowd. The model included the following variables of emotion: negative, negative comfortable, positive, positive comfortable and positive spiritual and variables of negative behaviors; aggressive and hazardous acts. The study demonstrated that emotions of negative, negative comfortable, positive spiritual and positive emotion have a direct influence on aggressive behavior whereas emotion of negative comfortable, positive spiritual and positive have a direct influence on hazardous acts behavior. The sensitivity analysis showed that a low level of negative and negative comfortable emotions leads to a lower level of aggressive and hazardous behavior. Findings of the study can be further improved to identify the exact cause and risk factors of crowd-related incidents in preventing crowd disasters during the mass gathering events.

Ramli, Nurulhuda; Ghani, Noraida Abdul; Hatta, Zulkarnain Ahmad; Hashim, Intan Hashimah Mohd; Sulong, Jasni; Mahudin, Nor Diana Mohd; Rahman, Shukran Abd; Saad, Zarina Mat

2014-12-01

388

Valkyrie: A UML-Based Model-Driven Environment for Model-Driven Software Engineering  

E-print Network

Valkyrie: A UML-Based Model-Driven Environment for Model-Driven Software Engineering Thomas Transformations; Code Generation; EMF; Ecore; GMF; Acceleo. Abstract: Model-driven software engineering aims and design, which are based on package diagrams, class diagrams, statecharts, and the textual UML Action

Westfechtel, Bernhard

389

Modeling Pollutant Emissions of Diesel Engine based on Kriging Models: a  

E-print Network

Modeling Pollutant Emissions of Diesel Engine based on Kriging Models: a Comparison between problems, modelling errors, Automotive emissions, Diesel engines 1. INTRODUCTION The automotive industry.denis-vidal@math.univ-lille1.fr, ghislaine.joly-blanchard@utc.fr) Abstract: In order to optimize the performance of a diesel

Paris-Sud XI, Université de

390

Modeling emergent border-crossing behaviors during pandemics  

NASA Astrophysics Data System (ADS)

Modeling real-world scenarios is a challenge for traditional social science researchers, as it is often hard to capture the intricacies and dynamisms of real-world situations without making simplistic assumptions. This imposes severe limitations on the capabilities of such models and frameworks. Complex population dynamics during natural disasters such as pandemics is an area where computational social science can provide useful insights and explanations. In this paper, we employ a novel intent-driven modeling paradigm for such real-world scenarios by causally mapping beliefs, goals, and actions of individuals and groups to overall behavior using a probabilistic representation called Bayesian Knowledge Bases (BKBs). To validate our framework we examine emergent behavior occurring near a national border during pandemics, specifically the 2009 H1N1 pandemic in Mexico. The novelty of the work in this paper lies in representing the dynamism at multiple scales by including both coarse-grained (events at the national level) and finegrained (events at two separate border locations) information. This is especially useful for analysts in disaster management and first responder organizations who need to be able to understand both macro-level behavior and changes in the immediate vicinity, to help with planning, prevention, and mitigation. We demonstrate the capabilities of our framework in uncovering previously hidden connections and explanations by comparing independent models of the border locations with their fused model to identify emergent behaviors not found in either independent location models nor in a simple linear combination of those models.

Santos, Eunice E.; Santos, Eugene; Korah, John; Thompson, Jeremy E.; Gu, Qi; Kim, Keum Joo; Li, Deqing; Russell, Jacob; Subramanian, Suresh; Zhang, Yuxi; Zhao, Yan

2013-06-01

391

Aggregating social behavior into person models: perceiver-induced consistency.  

PubMed

Two experiments explored the role of perceivers (judges) in aggregating social behavior into impressions. In Experiment 1, it was predicted and found that judges influence impressions (i.e., eye-of-the-beholder effects) not only because they disagree on how to interpret single acts but because they aggregate multiple acts in unique ways to arrive at idiosyncratic impressions. Using D. A. Kenny's (1991) general model of accuracy and consensus, it was found that judges perceived much greater consistency in the behavior of targets across situations when they were asked to aggregate the behavior than when they were not. Differential interpretation of single acts did not change as a function of aggregating behavior. This aggregation process was characterized as the construction of models of persons. In Experiment 2, the concept of person models was explored further, and it was argued that perceivers develop these models on the basis of what is viewed as the central concept of a target. For any given target, a limited number of models can be identified, and different perceivers develop different models. The particular model formed has implications for the perceiver's underlying memory representation and the perceived personality profile of the target. PMID:8169759

Park, B; DeKay, M L; Kraus, S

1994-03-01

392

Quantum Mechanical Model of Emotional Robot Behaviors  

Microsoft Academic Search

In this paper the emotional model of the humanoid Cynthea (Cybernetic Networked Humanoid Emotional Agent) robot is presented. The robot is explained at two lev- els: the cognitive level is described by the CRL language, and the emotional level manipulates the language in a data independent way. An emotional mapping is introduced and is used to alter the language words

Martin Lukac; Marek A. Perkowski

2007-01-01

393

A Simple Model of Herd Behavior  

Microsoft Academic Search

The author analyzes a sequential decision model in which each decisionmaker looks at the decisions made by previous decisionmakers in taking her own decision. This is rational for her because these other decisionmakers may have some information that is important for her. The author then shows that the decision rules that are chosen by optimizing individuals will be characterized by

Abhijit V Banerjee

1992-01-01

394

A Social Neuroscientific Model of Vocational Behavior  

ERIC Educational Resources Information Center

In this article, the separate literatures of a neurobiologically based approach system and vocational interests are reviewed and integrated into a social neuroscientific model of the processes underlying interests, based upon the idea of selective approach motivation. The authors propose that vocational interests describe the types of stimuli that…

Hansen, Jo-Ida C.; Sullivan, Brandon A.; Luciana, Monica

2011-01-01

395

The Force Model: Concept, Behavior, Interpretation  

Microsoft Academic Search

Most experiments in research on autonomous agents and mobile robots are performed either in simulation or on robots with static physical properties; evolvable hardware is hardly ever used. One of the very rare exceptions is the eyebot on which Lichtensteiger and Eggenberger have evolved simpli£ed insect eyes (L. Lichtensteiger and P. Eggenberger, 1999). Even though substantially improved, the evolutionary models

Ralf Salomon

2003-01-01

396

Fusing Quantitative Requirements Analysis with Model-based Systems Engineering  

NASA Technical Reports Server (NTRS)

A vision is presented for fusing quantitative requirements analysis with model-based systems engineering. This vision draws upon and combines emergent themes in the engineering milieu. "Requirements engineering" provides means to explicitly represent requirements (both functional and non-functional) as constraints and preferences on acceptable solutions, and emphasizes early-lifecycle review, analysis and verification of design and development plans. "Design by shopping" emphasizes revealing the space of options available from which to choose (without presuming that all selection criteria have previously been elicited), and provides means to make understandable the range of choices and their ramifications. "Model-based engineering" emphasizes the goal of utilizing a formal representation of all aspects of system design, from development through operations, and provides powerful tool suites that support the practical application of these principles. A first step prototype towards this vision is described, embodying the key capabilities. Illustrations, implications, further challenges and opportunities are outlined.

Cornford, Steven L.; Feather, Martin S.; Heron, Vance A.; Jenkins, J. Steven

2006-01-01

397

Numerical Modeling of Pulse Detonation Rocket Engine Gasdynamics and Performance  

NASA Technical Reports Server (NTRS)

Pulse detonation engines (PDB) have generated considerable research interest in recent years as a chemical propulsion system potentially offering improved performance and reduced complexity compared to conventional gas turbines and rocket engines. The detonative mode of combustion employed by these devices offers a theoretical thermodynamic advantage over the constant-pressure deflagrative combustion mode used in conventional engines. However, the unsteady blowdown process intrinsic to all pulse detonation devices has made realistic estimates of the actual propulsive performance of PDES problematic. The recent review article by Kailasanath highlights some of the progress that has been made in comparing the available experimental measurements with analytical and numerical models.

Morris, C. I.

2003-01-01

398

Modelling of supercharger turbines in internal-combustion engines  

Microsoft Academic Search

A new physical model to calculate the fluid-dynamic behaviour and energy conversion in turbocharger turbines for internal-combustion (I.C.) engines is presented. The model has been developed to be used as a boundary condition in wave action models. The model uses data from the turbine characteristic curves and it is based on the idealization of the turbine by simple elements: ideal

F. Payri; J. Benajes; M. Reyes

1996-01-01

399

Human Modeling for Ground Processing Human Factors Engineering Analysis  

NASA Technical Reports Server (NTRS)

There have been many advancements and accomplishments over the last few years using human modeling for human factors engineering analysis for design of spacecraft. The key methods used for this are motion capture and computer generated human models. The focus of this paper is to explain the human modeling currently used at Kennedy Space Center (KSC), and to explain the future plans for human modeling for future spacecraft designs

Stambolian, Damon B.; Lawrence, Brad A.; Stelges, Katrine S.; Steady, Marie-Jeanne O.; Ridgwell, Lora C.; Mills, Robert E.; Henderson, Gena; Tran, Donald; Barth, Tim

2011-01-01

400

Human Modeling For Ground Processing Human Factors Engineering Analysis  

NASA Technical Reports Server (NTRS)

There have been many advancements and accomplishments over that last few years using human modeling for human factors engineering analysis for design of spacecraft and launch vehicles. The key methods used for this are motion capture and computer generated human models. The focus of this paper is to explain the different types of human modeling used currently and in the past at Kennedy Space Center (KSC) currently, and to explain the future plans for human modeling for future spacecraft designs.

Tran, Donald; Stambolian, Damon; Henderson, Gena; Barth, Tim

2011-01-01

401

Predicted vs. scale model and flight test UDF engine noise  

Microsoft Academic Search

This paper presents an overview of the development of a frequency-domain, noncompact-source noise prediction model for the unducted fan (UDF) engine. A brief description of the acoustic modeling approach and basic equations employed is given, together with a summary of the aerodynamic characteristics utilized in the noise prediction model. Scale model test results obtained from both low-speed and high-speed wind

C. E. Whitfield; P. R. Gliebe

1990-01-01

402

Systems Model for Improving Standards and Retention In Engineering Education  

NSDL National Science Digital Library

This paper describes a systems model for improving standards in engineering education and at the same time maintaining high retention rate for all engineering students in the educational system. A systems approach methodology adopted for this research is a technique of taking into account all relevant factors affecting quality education and student retention. A four-step procedure has been adopted for the model, namely: problem diagnosis, evaluation and analysis, system model design, and design implementation. Target Audience: 2-4 Year College Faculty/Administrators

Owusu, Yaw A. (Yaw Akyeaw-Brimpon)

403

NTP system simulation and detailed nuclear engine modeling  

NASA Technical Reports Server (NTRS)

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

1993-01-01

404

EHF (Extremely High Frequency) telecommunications system engineering model  

Microsoft Academic Search

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

K. C. Allen

1986-01-01

405

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

406

Modeling Off-Nominal Behavior in SysML  

NASA Technical Reports Server (NTRS)

Specification and development of fault management functionality in systems is performed in an ad hoc way - more of an art than a science. Improvements to system reliability, availability, safety and resilience will be limited without infusion of additional formality into the practice of fault management. Key to the formalization of fault management is a precise representation of off-nominal behavior. Using the upcoming Soil Moisture Active-Passive (SMAP) mission for source material, we have modeled the off-nominal behavior of the SMAP system during its initial spin-up activity, using the System Modeling Language (SysML). In the course of developing these models, we have developed generic patterns for capturing off-nominal behavior in SysML. We show how these patterns provide useful ways of reasoning about the system (e.g., checking for completeness and effectiveness) and allow the automatic generation of typical artifacts (e.g., success trees and FMECAs) used in system analyses.

Day, John C.; Donahue, Kenneth; Ingham, Michel; Kadesch, Alex; Kennedy, Andrew K.; Post, Ethan

2012-01-01

407

Modeling the behavior of the computer-assisted instruction user  

SciTech Connect

The field of computer-assisted instruction CAI contains abundant studies on effectiveness of particular programs or systems. However, the nature of the field is such that the computer is the focus of research, not the users. Few research studies have focused on the behavior of the individual CAI user. Morgan (1981) stated that descriptive studies are needed to clarify what the important phenomena of user behavior are. The need for such studies is particularly acute in computer-assisted instruction. Building a behavioral model would enable us to understand problem-solving strategies and rules applied by the user during a CAI experience. Also, courseware developers could use this information to design tutoring systems that are more responsive to individual differences than our present CAI is. This paper proposes a naturalistic model for evaluating both affective and cognitive characteristics of the CAI user. It begins with a discussion of features of user behavior, followed by a description of evaluation methodology that can lead to modeling user behavior. The paper concludes with a discussion of how implementation of this model can contribute to the fields of CAI and cognitive psychology.

Stoddard, M.L.

1983-01-01

408

2010 Travel Behavior Inventory: Model Development  

E-print Network

Stops 3 Stops Total Home: Work 3,435 3,440 1,265 858 8,998 Home: School/University 3,659 518 247 0 4,424 Home: Nonmandatory, school escort 13,944 3,911 1,329 880 20,064 Home: non-school escort 872 106 32 0 benefits ­ Environmental impacts Forecast Models #12;3 · Non-home based trips · Lack of policy sensitivity

Minnesota, University of

409

Slicing Behavior Tree Models for Verification  

Microsoft Academic Search

\\u000a Program slicing is a reduction technique that removes irrelevant parts of a program automatically, based on dependencies.\\u000a It is used in the context of documentation to improve the user’s understanding as well as for reducing the size of a program\\u000a when analysing. In this paper we describe an approach for slicing not program code but models of software or systems

Nisansala Yatapanage; Kirsten Winter; Saad Zafar

2010-01-01

410

ADVANCES IN ENERGY FORECASTING MODELS BASED ON ENGINEERING ECONOMICS  

Microsoft Academic Search

New energy efficiency policies have been introduced around the world. Historically, most energy models were reasonably equipped to assess the impact of classical policies, such as a subsidy or change in taxation. However, these tools are often insufficient to assess the impact of alternative policy instruments. We evaluate the so-called engineering economic models used to assess future industrial energy use.

Ernst Worrell; Stephan Ramesohl; Gale Boyd

2004-01-01

411

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

412

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

413

A model specification for FRP 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

2003-01-01

414

Virtual Prototypes and Product Models in Mechanical Engineering  

Microsoft Academic Search

This paper gives an overview of some of the modelling and virtual prototyping techniquesused in product realization, with emphasis on the mechanical engineering eld.It is pointed out that virtual prototypes, in the commonly accepted sense of computermodels permitting realistic graphical simulation, represent only one class amongst themany types of computer models used in design and planning for manufacture. Each suchmodel

Michael J. Pratt

1995-01-01

415

MODELS OF CYBERINFRASTRUCTURE-BASED ENTERPRISES AND THEIR ENGINEERING  

E-print Network

the elements that integrate persons and the environment with the enterprises. Computerized manufacturing, e-commerce of profit. More telling is, perhaps, the principles revealed for I and O. They define the modelsChapter 8 MODELS OF CYBERINFRASTRUCTURE-BASED ENTERPRISES AND THEIR ENGINEERING An Evolutionary

Hsu, Cheng

416

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

417

Information modelling in the construction industry: The information engineering approach  

Microsoft Academic Search

Modelling of knowledge in the construction industry is a cumbersome task because of the large amount of data involved and the lack of automated information-modelling tools. Adoption of a method and an automated CASE (Computer-Aided Software Engineering) tool could eliminate many problems encountered in the development of information systems in the construction industry. In particular, this approach may help to

G. F. Aouad; J. A. Kirkhami; P. S. Brandon; F. E. Brown; G. S. Cooper; S. Ford; R. E. Oxman; M. Sarshar; B. Young

1993-01-01

418

Generic domain models in software engineering  

NASA Technical Reports Server (NTRS)

This paper outlines three research directions related to domain-specific software development: (1) reuse of generic models for domain-specific software development; (2) empirical evidence to determine these generic models, namely elicitation of mental knowledge schema possessed by expert software developers; and (3) exploitation of generic domain models to assist modelling of specific applications. It focuses on knowledge acquisition for domain-specific software development, with emphasis on tool support for the most important phases of software development.

Maiden, Neil

1992-01-01

419

A verification and validation process for model-driven engineering  

NASA Astrophysics Data System (ADS)

Model Driven Engineering practitioners already benefit from many well established verification tools, for Object Constraint Language (OCL), for instance. Recently, constraint satisfaction techniques have been brought to Model-Driven Engineering (MDE) and have shown promising results on model verification tasks. With all these tools, it becomes possible to provide users with formal support from early model design phases to model instantiation phases. In this paper, a selection of such tools and methods is presented, and an attempt is made to define a verification and validation process for model design and instance creation centered on UML (Unified Modeling Language) class diagrams and declarative constraints, and involving the selected tools. The suggested process is illustrated with a simple example.

Delmas, R.; Pires, A. F.; Polacsek, T.

2013-12-01

420

Integrating sensorimotor systems in a robot model of cricket behavior  

NASA Astrophysics Data System (ADS)

The mechanisms by which animals manage sensorimotor integration and coordination of different behaviors can be investigated in robot models. In previous work the first author has build a robot that localizes sound based on close modeling of the auditory and neural system in the cricket. It is known that the cricket combines its response to sound with other sensorimotor activities such as an optomotor reflex and reactions to mechanical stimulation for the antennae and cerci. Behavioral evidence suggests some ways these behaviors may be integrated. We have tested the addition of an optomotor response, using an analog VLSI circuit developed by the second author, to the sound localizing behavior and have shown that it can, as in the cricket, improve the directness of the robot's path to sound. In particular it substantially improves behavior when the robot is subject to a motor disturbance. Our aim is to better understand how the insect brain functions in controlling complex combinations of behavior, with the hope that this will also suggest novel mechanisms for sensory integration on robots.

Webb, Barbara H.; Harrison, Reid R.

2000-10-01

421

Modeling Candle Flame Behavior In Variable Gravity  

NASA Technical Reports Server (NTRS)

The burning of a candle, as typical non-propagating diffusion flame, has been used by a number of researchers to study the effects of electric fields on flame, spontaneous flame oscillation and flickering phenomena, and flame extinction. In normal gravity, the heat released from combustion creates buoyant convection that draws oxygen into the flame. The strength of the buoyant flow depends on the gravitational level and it is expected that the flame shape, size and candle burning rate will vary with gravity. Experimentally, there exist studies of candle burning in enhanced gravity (i.e. higher than normal earth gravity, g(sub e)), and in microgravity in drop towers and space-based facilities. There are, however, no reported experimental data on candle burning in partial gravity (g < g(sub e)). In a previous numerical model of the candle flame, buoyant forces were neglected. The treatment of momentum equation was simplified using a potential flow approximation. Although the predicted flame characteristics agreed well with the experimental results, the model cannot be extended to cases with buoyant flows. In addition, because of the use of potential flow, no-slip boundary condition is not satisfied on the wick surface. So there is some uncertainty on the accuracy of the predicted flow field. In the present modeling effort, the full Navier-Stokes momentum equations with body force term is included. This enables us to study the effect of gravity on candle flames (with zero gravity as the limiting case). In addition, we consider radiation effects in more detail by solving the radiation transfer equation. In the previous study, flame radiation is treated as a simple loss term in the energy equation. Emphasis of the present model is on the gas-phase processes. Therefore, the detailed heat and mass transfer phenomena inside the porous wick are not treated. Instead, it is assumed that a thin layer of liquid fuel coated the entire wick surface during the burning process. This is the limiting case that the mass transfer process in the wick is much faster than the evaporation process at the wick surface.

Alsairafi, A.; Tien, J. S.; Lee, S. T.; Dietrich, D. L.; Ross, H. D.

2003-01-01

422

Quantum heat engine: A fully quantized model  

NASA Astrophysics Data System (ADS)

Motivated by the growing interest in the nanophysics and the field of quantum thermodynamics [J. Gemmer, M. Michel, G. Mahler, Springer, 2005] we study a system consisting of two different 2-level atoms (spins) coupled to a quantum oscillator (resonator field mode), and each spin linked to a heat bath with different temperatures. We find that the energy gradient imposed on the system and the “coherent driving” of the two atoms achieved by the oscillator make this system act as a thermodynamic machine. We analyze the engine dynamics using the recently developed definitions of heat flux and power [E. Boukobza, D.J. Tannor, Phys. Rev. A. 74 (2006) 063823; H. Weimer, M.J. Henrich, F. Rempp, H. Schröder, G. Mahler, Eur. Phys. Lett. 83 (3) (2008) 30008]. The system can work as heat engine (laser) or a heat pump in a non-cyclic continuous mode. We characterize the properties of the resonator field. The concept of work and heat for this machine is discussed.

Youssef, M.; Mahler, G.; Obada, A.-S. F.

2010-01-01

423

Sensitivity analysis of the fission gas behavior model in BISON.  

SciTech Connect

This report summarizes the result of a NEAMS project focused on sensitivity analysis of a new model for the fission gas behavior (release and swelling) in the BISON fuel performance code of Idaho National Laboratory. Using the new model in BISON, the sensitivity of the calculated fission gas release and swelling to the involved parameters and the associated uncertainties is investigated. The study results in a quantitative assessment of the role of intrinsic uncertainties in the analysis of fission gas behavior in nuclear fuel.

Swiler, Laura Painton; Pastore, Giovanni [Idaho National Laboratory, Idaho Fall, ID; Perez, Danielle [Idaho National Laboratory, Idaho Fall, ID; Williamson, Richard [Idaho National Laboratory, Idaho Fall, ID

2013-05-01

424

Artificial Intelligence Software Engineering (AISE) model  

NASA Technical Reports Server (NTRS)

The American Institute of Aeronautics and Astronautics has initiated a committee on standards for Artificial Intelligence. Presented are the initial efforts of one of the working groups of that committee. A candidate model is presented for the development life cycle of knowledge based systems (KBSs). The intent is for the model to be used by the aerospace community and eventually be evolved into a standard. The model is rooted in the evolutionary model, borrows from the spiral model, and is embedded in the standard Waterfall model for software development. Its intent is to satisfy the development of both stand-alone and embedded KBSs. The phases of the life cycle are shown and detailed as are the review points that constitute the key milestones throughout the development process. The applicability and strengths of the model are discussed along with areas needing further development and refinement by the aerospace community.

Kiss, Peter A.

1990-01-01

425

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

426

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.

427

GETRAN: A generic, modularly structured computer code for simulation of dynamic behavior of aero- and power generation gas turbine engines  

SciTech Connect

The design concept, the theoretical background essential for the development of the modularly structured simulation code GETRAN, and several critical simulation cases are presented in this paper. The code being developed under contract with NASA Lewis Research Center is capable of simulating the nonlinear dynamic behavior of single- and multispool core engines, turbofan engines, and power generation gas turbine engines under adverse dynamic operating conditions. The modules implemented into GETRAN correspond to components of existing and new-generation aero- and stationary gas turbine engines with arbitrary configuration and arrangement. For precise simulation of turbine and compressor components, row-by-row diabatic and adiabatic calculation procedures are implemented that account for the specific turbine and compressor cascade, blade geometry, and characteristics. The nonlinear, dynamic behavior of the subject engine is calculated solving a number of systems of partial differential equations, which describe the unsteady behavior of each component individually. To identify each differential equation system unambiguously, special attention is paid to the addressing of each component. The code is capable of executing the simulation procedure at four levels, which increase with the degree of complexity of the system and dynamic event. As representative simulations, four different transient cases with single- and multispool thrust and power generation engines were simulated. These transient cases vary from throttling the exit nozzle area, operation with fuel schedule, rotor speed control, to rotating stall and surge.

Schobeiri, M.T.; Attia, M.; Lippke, C. (Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering)

1994-07-01

428

Joint Modeling of Longitudinal Data in Multiple Behavioral Change  

PubMed Central

Multiple behavioral change is an exciting and evolving research area, albeit one that presents analytic challenges to investigators. This manuscript considers the problem of modeling jointly trajectories for two or more possibly non-normally distributed dependent variables, such as marijuana smoking and risky sexual activity, collected longitudinally. Of particular scientific interest is applying such modeling to elucidate the nature of the interaction, if any, between an intervention and personal characteristics, such as sensation seeking and impulsivity. We describe three analytic approaches: generalized linear mixed modeling, group-based trajectory modeling, and latent growth curve modeling. In particular, we identify the strengths and weaknesses of these analytic approaches and assess their impact (or lack thereof) on the psychological and behavioral science literature. We also compare what investigators have been doing analytically versus what they might want to be doing in the future and discuss the implications for basic and translational research. PMID:21196429

Charnigo, Richard; Kryscio, Richard; Bardo, Michael T.; Lynam, Donald; Zimmerman, Rick S.

2010-01-01

429

Asymptotic behavior of solutions of the renormalization group K-epsilon turbulence model  

NASA Technical Reports Server (NTRS)

Presently, the only efficient way to calculate turbulent flows in complex geometries of engineering interest is to use Reynolds-average Navier-Stokes (RANS) equations. As compared to the original Navier-Stokes problem, these RANS equations posses much more complicated nonlinear structure and may exhibit far more complex nonlinear behavior. In certain cases, the asymptotic behavior of such models can be studied analytically which, aside from being an interesting fundamental problem, is important for better understanding of the internal structure of the models as well as to improve their performances. The renormalization group (RNG) K-epsilon turbulence model, derived directly from the incompresible Navier-Stokes equations, is analyzed. It has already been used to calculate a variety of turbulent and transitional flows in complex geometries. For large values of the RNG viscosity parameter, the model may exhibit singular behavior. In the form of the RNG K-epsilon model that avoids the use of explicit wall functions, a = 1, so the RNG viscosity parameter must be smaller than 23.62 to avoid singularities.

Yakhot, A.; Staroselsky, I.; Orszag, S. A.

1994-01-01

430

Fatigue behavior of two alloys for Space Shuttle applications. [Inconel 903 and 718 for main engine  

NASA Technical Reports Server (NTRS)

Two superalloys used extensively in the Space Shuttle main engine are Incoloy 903 and Inconel 718. The fatigue behavior of the two alloys under varying conditions is considered. Three heats of Incoloy 903 and two of Inconel 718 were used in the study. Material was tested in several conditions, including mill polish, longitudinal mill polish, transverse mill polish, chemically milled, chemically milled plus shotpeened on one side and on both sides, gas tungsten arc welded, and electron beam welded. Both round and flat tensile specimens were tested in universal test machines. It was found that surface condition influences test results. Transverse scratches resulting from polishing and rougher surfaces lower the stress at runout in relation to that obtained on longitudinally polished and/or smooth-surfaced specimens.

Adsit, N. R.; Block, S. J.

1978-01-01

431

Mathematical modeling of uniaxial mechanical properties of collagen gel scaffolds for vascular tissue engineering.  

PubMed

Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.). When Akaike criterion is used, the best is the Mooney-Rivlin inspired model. PMID:25834840

Irastorza, Ramiro M; Drouin, Bernard; Blangino, Eugenia; Mantovani, Diego

2015-01-01

432

Mathematical Modeling of Uniaxial Mechanical Properties of Collagen Gel Scaffolds for Vascular Tissue Engineering  

PubMed Central

Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.). When Akaike criterion is used, the best is the Mooney-Rivlin inspired model.

Irastorza, Ramiro M.; Drouin, Bernard; Blangino, Eugenia; Mantovani, Diego

2015-01-01

433

DEFINING THE PLAYERS IN HIGHER-ORDER NETWORKS: PREDICTIVE MODELING FOR REVERSE ENGINEERING FUNCTIONAL INFLUENCE NETWORKS  

SciTech Connect

A difficult problem that is currently growing rapidly due to the sharp increase in the amount of high-throughput data available for many systems is that of determining useful and informative causative influence networks. These networks can be used to predict behavior given observation of a small number of components, predict behavior at a future time point, or identify components that are critical to the functioning of the system under particular conditions. In these endeavors incorporating observations of systems from a wide variety of viewpoints can be particularly beneficial, but has often been undertaken with the objective of inferring networks that are generally applicable. The focus of the current work is to integrate both general observations and measurements taken for a particular pathology, that of ischemic stroke, to provide improved ability to produce useful predictions of systems behavior. A number of hybrid approaches have recently been proposed for network generation in which the Gene Ontology is used to filter or enrich network links inferred from gene expression data through reverse engineering methods. These approaches have been shown to improve the biological plausibility of the inferred relationships determined, but still treat knowledge-based and machine-learning inferences as incommensurable inputs. In this paper, we explore how further improvements may be achieved through a full integration of network inference insights achieved through application of the Gene Ontology and reverse engineering methods with specific reference to the construction of dynamic models of transcriptional regulatory networks. We show that integrating two approaches to network construction, one based on reverse-engineering from conditional transcriptional data, one based on reverse-engineering from in situ hybridization data, and another based on functional associations derived from Gene Ontology, using probabilities can improve results of clustering as evaluated by a predictive model of transcriptional expression levels.

McDermott, Jason E.; Costa, Michelle N.; Stevens, S.L.; Stenzel-Poore, Mary; Sanfilippo, Antonio P.

2011-01-20

434

Behavior changes in SIS STD models with selective mixing  

SciTech Connect

The authors propose and analyze a heterogeneous, multigroup, susceptible-infective-susceptible (SIS) sexually transmitted disease (STD) model where the desirability and acceptability in partnership formations are functions of the infected individuals. They derive explicit formulas for the epidemic thresholds, prove the existence and uniqueness of the equilibrium states for the two-group model and provide a complete analysis of their local and global stability. The authors then investigate the effects of behavior changes on the transmission dynamics and analyze the sensitivity of the epidemic to the magnitude of the behavior changes. They verify that if people modify their behavior to reduce the probability of infection with individuals in highly infected groups, through either reduced contacts, reduced partner formations, or using safe sex, the infection level may be decreased. However, if people continue to have intragroup and intergroup partnerships, then changing the desirability and acceptability formation cannot eradicate the epidemic once it exceeds the epidemic threshold.

Hyman, J.M. [Los Alamos National Lab., NM (United States). Center for Nonlinear Studies] [Los Alamos National Lab., NM (United States). Center for Nonlinear Studies; Li, J. [Univ. of Alabama, Huntsville, AL (United States). Dept. of Mathematical Sciences] [Univ. of Alabama, Huntsville, AL (United States). Dept. of Mathematical Sciences

1997-08-01

435

Development of empirically based burning rate sub-models for a natural gas engine  

Microsoft Academic Search

Computer models of engine processes are valuable tools for predicting and analyzing engine performance and allow exploration of many engine design alternatives in an inexpensive fashion. At the present work, experimentally based burning rate sub-models for flame initiation and propagation periods were developed for a natural gas engine. The sub-models do not require any knowledge of the flame shape and

Seref Soylu; Jon Van Gerpen

2004-01-01

436

A Comparative Study for Search Engines Business Model - Based on the Case of Baidu and Google  

Microsoft Academic Search

Due to the advantages of the search engine's business value, search engine has been rapidly developed in the network economy era. With the market competition become white-hot, search engine enterprises are facing the problem how to choose an effective business model. A search engine's business model was designed in this paper. Based on the six dimensions in business model, a

Hanpo Hou; Haibo Li; Jing Wen

2010-01-01

437

Explicit-Ready Nonlinear Model Predictive Control for Turbocharged Spark-Ignited Engines  

E-print Network

. In this study we propose a nonlinear model predictive control strategy based on a physical engine model engines. Modern combustion engines can now be defined as multi-input multi- output nonlinear systems). In this study, a nonlinear predictive controller, using a physics-based engine model, has been designed

Paris-Sud XI, Université de

438

Engineering Workshop 3D Modeling Using TinkerCAD  

E-print Network

using TinkerCAD · TinkerCad is used for online 3D modeling · Learn how to print the clip on a 3D printer the hole and the clip #12;Congratulations! You made a 3D model! #12;Now To Print It... Our Printers · MakerEngineering Workshop 3D Modeling Using TinkerCAD Sci-Ed Day 2014 Brookhaven National Laboratory

Ohta, Shigemi

439

Modeling semantic information in engineering applications: a review  

Microsoft Academic Search

Due to the latest advances of information technology and the increasing complexity of engineering applications, it is becoming\\u000a more and more important to model semantic information. There are many modeling methodologies to do the work of modeling semantic\\u000a information instead of natural language processing. Since this field is very broad, the comparison discussed here is not an\\u000a exhaustive study but

Kunmei Wen; Yong Zeng; Ruixuan Li; Jianqiang Lin

440

Models and metrics for software management and engineering  

NASA Technical Reports Server (NTRS)

This paper attempts to characterize and present a state of the art view of several quantitative models and metrics of the software life cycle. These models and metrics can be used to aid in managing and engineering software projects. They deal with various aspects of the software process and product, including resources allocation and estimation, changes and errors, size, complexity and reliability. Some indication is given of the extent to which the various models have been used and the success they have achieved.

Basili, V. R.

1988-01-01

441

Quasi-One-Dimensional Modeling of Pulse Detonation Rocket Engines  

NASA Technical Reports Server (NTRS)

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 CFD model for a PDRE & described and implemented. A parametric study of the effect of blowdown pressure ratio on the performance of an optimized, fixed PDRE nozzle configuration is reported. The results are compared to a steady-state rocket system using similar modeling assumptions.

Morris, Christopher I.

2003-01-01

442

Animal Models for Vascular Tissue-Engineering  

PubMed Central

Due to 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, pre-clinical 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.

2013-01-01

443

Purposive behavior of honeybees as the basis of an experimental search engine  

Microsoft Academic Search

The foraging behavior of active honeybee colonies serves as a model for Web explorers that are reactive, proactive, and robust.\\u000a The Web explorers are developed to forage a simulated information ecosystem—the Internet—for useful information. Each explorer\\u000a is designed to detect and report dynamic changes within the infrastructure of the Internet to its Web explorer dispatcher,\\u000a which is responsible for coordinating

Reginald L. Walker

2007-01-01

444

Apparent Transition Behavior of Widely-Used Turbulence Models  

NASA Technical Reports Server (NTRS)

The Spalart-Allmaras and the Menter SST kappa-omega turbulence models are shown to have the undesirable characteristic that, for fully turbulent computations, a transition region can occur whose extent varies with grid density. Extremely fine two-dimensional grids over the front portion of an airfoil are used to demonstrate the effect. As the grid density is increased, the laminar region near the nose becomes larger. In the Spalart-Allmaras model this behavior is due to convergence to a laminar-behavior fixed point that occurs in practice when freestream turbulence is below some threshold. It is the result of a feature purposefully added to the original model in conjunction with a special trip function. This degenerate fixed point can also cause nonuniqueness regarding where transition initiates on a given grid. Consistent fully turbulent results can easily be achieved by either using a higher freestream turbulence level or by making a simple change to one of the model constants. Two-equation kappa-omega models, including the SST model, exhibit strong sensitivity to numerical resolution near the area where turbulence initiates. Thus, inconsistent apparent transition behavior with grid refinement in this case does not appear to stem from the presence of a degenerate fixed point. Rather, it is a fundamental property of the kappa-omega model itself, and is not easily remedied.

Rumsey, Christopher L.

2006-01-01

445

Modeling motivational deficits in mouse models of schizophrenia: Behavior analysis as a guide for neuroscience  

Microsoft Academic Search

In recent years it has become possible to develop animal models of psychiatric disease in genetically modified mice. While great strides have been made in the development of genetic and neurobiological tools with which to model psychiatric disease, elucidation of neural and molecular mechanisms thought to underlie behavioral phenotypes has been hindered by an inadequate analysis of behavior. This is

Ryan D. Ward; Eleanor H. Simpson; Eric R. Kandel; Peter D. Balsam

2011-01-01

446

A Data-Driven Approach to Reverse Engineering Customer Engagement Models: Towards Functional Constructs  

PubMed Central

Online consumer behavior in general and online customer engagement with brands in particular, has become a major focus of research activity fuelled by the exponential increase of interactive functions of the internet and social media platforms and applications. Current research in this area is mostly hypothesis-driven and much debate about the concept of Customer Engagement and its related constructs remains existent in the literature. In this paper, we aim to propose a novel methodology for reverse engineering a consumer behavior model for online customer engagement, based on a computational and data-driven perspective. This methodology could be generalized and prove useful for future research in the fields of consumer behaviors using questionnaire data or studies investigating other types of human behaviors. The method we propose contains five main stages; symbolic regression analysis, graph building, community detection, evaluation of results and finally, investigation of directed cycles and common feedback loops. The ‘communities’ of questionnaire items that emerge from our community detection method form possible ‘functional constructs’ inferred from data rather than assumed from literature and theory. Our results show consistent partitioning of questionnaire items into such ‘functional constructs’ suggesting the method proposed here could be adopted as a new data-driven way of human behavior modeling. PMID:25036766

de Vries, Natalie Jane; Carlson, Jamie; Moscato, Pablo

2014-01-01

447

Tailoring surface phase transition and magnetic behaviors in BiFeO3 via doping engineering  

PubMed Central

The charge-spin interactions in multiferroic materials (e.g., BiFeO3) have attracted enormous attention due to their high potential for next generation information electronics. However, the weak and deficient manipulation of charge-spin coupling notoriously limits their commercial applications. To tailor the spontaneous charge and the spin orientation synergistically in BiFeO3 (BFO), in this report, the 3d element of Mn doping engineering is employed and unveils the variation of surface phase transition and magnetic behaviors by introducing chemical strain. The spontaneous ferroelectric response and the corresponding domain structures, magnetic behaviors and spin dynamics in Mn-doped BFO ceramics have been investigated systematically. Both the surface phase transition and magnetization were enhanced in BFO via Mn doping. The interaction between the spontaneous polarization charge and magnetic spin reorientation in Mn-doped BFO are discussed in detail. Moreover, our extensive electron paramagnetic resonance (EPR) results demonstrate that the 3d dopant plays a paramount role in the surface phase transition, which provides an alternative route to tune the charge-spin interactions in multiferroic materials. PMID:25774619

Yan, Feng; Xing, Guozhong; Wang, Rongming; Li, Lin

2015-01-01

448

Tailoring surface phase transition and magnetic behaviors in BiFeO3 via doping engineering  

NASA Astrophysics Data System (ADS)

The charge-spin interactions in multiferroic materials (e.g., BiFeO3) have attracted enormous attention due to their high potential for next generation information electronics. However, the weak and deficient manipulation of charge-spin coupling notoriously limits their commercial applications. To tailor the spontaneous charge and the spin orientation synergistically in BiFeO3 (BFO), in this report, the 3d element of Mn doping engineering is employed and unveils the variation of surface phase transition and magnetic behaviors by introducing chemical strain. The spontaneous ferroelectric response and the corresponding domain structures, magnetic behaviors and spin dynamics in Mn-doped BFO ceramics have been investigated systematically. Both the surface phase transition and magnetization were enhanced in BFO via Mn doping. The interaction between the spontaneous polarization charge and magnetic spin reorientation in Mn-doped BFO are discussed in detail. Moreover, our extensive electron paramagnetic resonance (EPR) results demonstrate that the 3d dopant plays a paramount role in the surface phase transition, which provides an alternative route to tune the charge-spin interactions in multiferroic materials.

Yan, Feng; Xing, Guozhong; Wang, Rongming; Li, Lin

2015-03-01

449

Tailoring surface phase transition and magnetic behaviors in BiFeO3 via doping engineering.  

PubMed

The charge-spin interactions in multiferroic materials (e.g., BiFeO3) have attracted enormous attention due to their high potential for next generation information electronics. However, the weak and deficient manipulation of charge-spin coupling notoriously limits their commercial applications. To tailor the spontaneous charge and the spin orientation synergistically in BiFeO3 (BFO), in this report, the 3d element of Mn doping engineering is employed and unveils the variation of surface phase transition and magnetic behaviors by introducing chemical strain. The spontaneous ferroelectric response and the corresponding domain structures, magnetic behaviors and spin dynamics in Mn-doped BFO ceramics have been investigated systematically. Both the surface phase transition and magnetization were enhanced in BFO via Mn doping. The interaction between the spontaneous polarization charge and magnetic spin reorientation in Mn-doped BFO are discussed in detail. Moreover, our extensive electron paramagnetic resonance (EPR) results demonstrate that the 3d dopant plays a paramount role in the surface phase transition, which provides an alternative route to tune the charge-spin interactions in multiferroic materials. PMID:25774619

Yan, Feng; Xing, Guozhong; Wang, Rongming; Li, Lin

2015-01-01

450

Behavioral impairments in animal models for zinc deficiency  

PubMed Central

Apart from teratogenic and pathological effects of zinc deficiency such as the occurrence of skin lesions, anorexia, growth retardation, depressed wound healing, altered immune function, impaired night vision, and alterations in taste and smell acuity, characteristic behavioral changes in animal models and human patients suffering from zinc deficiency have been observed. Given that it is estimated that about 17% of the worldwide population are at risk for zinc deficiency and that zinc deficiency is associated with a variety of brain disorders and disease states in humans, it is of major interest to investigate, how these behavioral changes will affect the individual and a putative course of a disease. Thus, here, we provide a state of the art overview about the behavioral phenotypes observed in various models of zinc deficiency, among them environmentally produced zinc deficient animals as well as animal models based on a genetic alteration of a particular zinc homeostasis gene. Finally, we compare the behavioral phenotypes to the human condition of mild to severe zinc deficiency and provide a model, how zinc deficiency that is associated with many neurodegenerative and neuropsychological disorders might modify the disease pathologies. PMID:25610379

Hagmeyer, Simone; Haderspeck, Jasmin Carmen; Grabrucker, Andreas Martin

2015-01-01

451

Student Nurses' Perceptions of Hospital Staff Modeling Behaviors.  

ERIC Educational Resources Information Center

This study used Brookfield's Critical Incident Questionnaire (CIQ) to assess the learning environment and student nurses' perceptions of hospital staff modeling behaviors. CIQs were distributed to Associate Degree female nursing students at United Medical Center in Cheyenne, Wyoming. A large majority (80%) of the 117 respondents identified…

Valentine, Sherise L.

452

Modeling Crowd Behavior Based on Social Comparison Theory: Extended Abstract  

E-print Network

or no verbal communication. Le Bon explains the homogeneous behavior of a crowd by two processes: (i) Imitation continuously #12;evolving since the 1950s. The key idea in this theory is that humans, lacking objective means cognitive model which, when executed individually by many agents, will cause them to behave as humans do

Kaminka, Gal A.

453

THE ECONOMICS OF ILLEGAL FISHING: A BEHAVIORAL MODEL  

Microsoft Academic Search

This paper analyzes the microeconomic behavior of fishers responding to imperfectly enforced regulations through illegal fishing and efforts to avoid detection. An intraseasonal optimization model is analyzed to determine optimal (profit-maximizing) harvesting strategies at the individual fisher level in response to input controls (such as gear or labor usage) or output controls (individual harvest quotas). For each regulatory option, the

Anthony T. Charles; R. Leigh Mazany; Melvin L. Cross

1999-01-01

454

Assessing Guessing Behavior Using the Three-Parameter Logistic Model.  

ERIC Educational Resources Information Center

Birnbaum's three-parameter logistic item response model was used to study guessing behavior of low ability examinees on the Graduate Record Examinations (GRE) General Test, Verbal Measure. GRE scoring procedures had recently changed, from a scoring formula which corrected for guessing, to number-right scoring. The three-parameter theory was used…

Kingston, Neal M.

455

Determinants of Academic Entrepreneurship Behavior: A Multilevel Model  

ERIC Educational Resources Information Center

It is well established that universities encourage the acquisition and dissemination of new knowledge among university community members and beyond. However, what is less well understood is how universities encourage entrepreneurial (opportunity discovery, evaluation, and exploiting) behavior. This research investigated a multilevel model of the…

Llano, Joseph Anthony

2010-01-01

456

Ab Initio Calculations to Model Anomalous Fluorine Behavior Milan Diebel*  

E-print Network

Ab Initio Calculations to Model Anomalous Fluorine Behavior Milan Diebel* Department of Physics December 2004) Implanted fluorine is observed to behave unusually in silicon, manifesting apparent uphill diffusion and reducing diffusion and enhancing activation of boron. In order to investigate fluorine

Dunham, Scott

457

A Model of Price Search Behavior in Electronic Marketplace.  

ERIC Educational Resources Information Center

Discussion of online consumer behavior focuses on the development of a conceptual model and a set of propositions to explain the main factors influencing online price search. Integrates the psychological search literature into the context of online searching by incorporating ability and cost to search for information into perceived search…

Jiang, Pingjun

2002-01-01

458

An Objective Evaluation of a Behavior Modeling Training Program.  

ERIC Educational Resources Information Center

Evaluated a behavior modeling training program for sales representatives (N=58) in relation to effects on their sales performance. Results showed participants increased their sales by an average of seven percent during the ensuing six-month period, while the control group showed a 3 percent decrease. (JAC)

Meyer, Herbert H.; Raich, Michael S.

1983-01-01

459

Sensitivity analysis techniques for models of human behavior.  

SciTech Connect

Human and social modeling has emerged as an important research area at Sandia National Laboratories due to its potential to improve national defense-related decision-making in the presence of uncertainty. To learn about which sensitivity analysis techniques are most suitable for models of human behavior, different promising methods were applied to an example model, tested, and compared. The example model simulates cognitive, behavioral, and social processes and interactions, and involves substantial nonlinearity, uncertainty, and variability. Results showed that some sensitivity analysis methods create similar results, and can thus be considered redundant. However, other methods, such as global methods that consider interactions between inputs, can generate insight not gained from traditional methods.

Bier, Asmeret Brooke

2010-09-01

460

Multifunctional Collaborative Modeling and Analysis Methods in Engineering Science  

NASA Technical Reports Server (NTRS)

Engineers are challenged to produce better designs in less time and for less cost. Hence, to investigate novel and revolutionary design concepts, accurate, high-fidelity results must be assimilated rapidly into the design, analysis, and simulation process. This assimilation should consider diverse mathematical modeling and multi-discipline interactions necessitated by concepts exploiting advanced materials and structures. Integrated high-fidelity methods with diverse engineering applications provide the enabling technologies to assimilate these high-fidelity, multi-disciplinary results rapidly at an early stage in the design. These integrated methods must be multifunctional, collaborative, and applicable to the general field of engineering science and mechanics. Multifunctional methodologies and analysis procedures are formulated for interfacing diverse subdomain idealizations including multi-fidelity modeling methods and multi-discipline analysis methods. These methods, based on the method of weighted residuals, ensure accurate compatibility of primary and secondary variables across the subdomain interfaces. Methods are developed using diverse mathematical modeling (i.e., finite difference and finite element methods) and multi-fidelity modeling among the subdomains. Several benchmark scalar-field and vector-field problems in engineering science are presented with extensions to multidisciplinary problems. Results for all problems presented are in overall good agreement with the exact analytical solution or the reference numerical solution. Based on the results, the integrated modeling approach using the finite element method for multi-fidelity discretization among the subdomains is identified as most robust. The multiple-method approach is advantageous when interfacing diverse disciplines in which each of the method's strengths are utilized. The multifunctional methodology presented provides an effective mechanism by which domains with diverse idealizations are interfaced. This capability rapidly provides the high-fidelity results needed in the early design phase. Moreover, the capability is applicable to the general field of engineering science and mechanics. Hence, it provides a collaborative capability that accounts for interactions among engineering analysis methods.

Ransom, Jonathan B.; Broduer, Steve (Technical Monitor)

2001-01-01

461

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

462

Augmented Network Model For Engineering System Design  

E-print Network

the components of a vehicle, the parts (or subsystems) of an airplane or the states of a formation of flying connections, like magnetic fields, chemical bonds or concentration levels, in fuel #12;Augmented Network Model

de Weck, Olivier L.

463

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

464

A step toward STEP-compatible engineering data management: the data models of product structure and engineering changes  

Microsoft Academic Search

In an iterative design process, there is a large amount of engineering data to be processed. Well-managed engineering data can ensure the competitiveness of companies in the competitive market. It has been recognized that a product data model is the basis for establishing engineering database. To fully support the complete product data representation in its life cycle, an international product

Ting-Kuo Peng; Amy J. C. Trappey

1998-01-01

465

Modeling Temporal Behavior in Large Networks: A Dynamic Mixed-Membership Model  

SciTech Connect

Given a large time-evolving network, how can we model and characterize the temporal behaviors of individual nodes (and network states)? How can we model the behavioral transition patterns of nodes? We propose a temporal behavior model that captures the 'roles' of nodes in the graph and how they evolve over time. The proposed dynamic behavioral mixed-membership model (DBMM) is scalable, fully automatic (no user-defined parameters), non-parametric/data-driven (no specific functional form or parameterization), interpretable (identifies explainable patterns), and flexible (applicable to dynamic and streaming networks). Moreover, the interpretable behavioral roles are generalizable, computationally efficient, and natively supports attributes. We applied our model for (a) identifying patterns and trends of nodes and network states based on the temporal behavior, (b) predicting future structural changes, and (c) detecting unusual temporal behavior transitions. We use eight large real-world datasets from different time-evolving settings (dynamic and streaming). In particular, we model the evolving mixed-memberships and the corresponding behavioral transitions of Twitter, Facebook, IP-Traces, Email (University), Internet AS, Enron, Reality, and IMDB. The experiments demonstrate the scalability, flexibility, and effectiveness of our model for identifying interesting patterns, detecting unusual structural transitions, and predicting the future structural changes of the network and individual nodes.

Rossi, R; Gallagher, B; Neville, J; Henderson, K

2011-11-11

466

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

467

The Use of Behavior Models for Predicting Complex Operations  

NASA Technical Reports Server (NTRS)

Modeling and simulation (M&S) plays an important role when complex human-system notions are being proposed, developed and tested within the system design process. National Aeronautics and Space Administration (NASA) as an agency uses many different types of M&S approaches for predicting human-system interactions, especially when it is early in the development phase of a conceptual design. NASA Ames Research Center possesses a number of M&S capabilities ranging from airflow, flight path models, aircraft models, scheduling models, human performance models (HPMs), and bioinformatics models among a host of other kinds of M&S capabilities that are used for predicting whether the proposed designs will benefit the specific mission criteria. The Man-Machine Integration Design and Analysis System (MIDAS) is a NASA ARC HPM software tool that integrates many models of human behavior with environment models, equipment models, and procedural / task models. The challenge to model comprehensibility is heightened as the number of models that are integrated and the requisite fidelity of the procedural sets are increased. Model transparency is needed for some of the more complex HPMs to maintain comprehensibility of the integrated model performance. This will be exemplified in a recent MIDAS v5 application model and plans for future model refinements will be presented.

Gore, Brian F.

2010-01-01

468

Animal models of behavioral dysfunctions: Basic concepts and classifications, and an evaluation strategy  

Microsoft Academic Search

In behavioral neurosciences, such as neurobiology and biopsychology, animal models make it possible to investigate brain–behavior relations, with the aim of gaining insight into normal and abnormal human behavior and its underlying neuronal and neuroendocrinological processes.Different types of animal models of behavioral dysfunctions are reviewed in this article. In order to determine the precise criteria that an animal model should

F. Josef van der Staay

2006-01-01

469

A Material Model for the Cyclic Behavior of Nitinol  

NASA Astrophysics Data System (ADS)

The uniaxial behavior of Nitinol in different forms and at different temperatures has been well documented in the literature. Mathematical models for the three-dimensional behavior of this class of materials, covering superelasticity, plasticity, and shape memory effects have been previously developed. Phenomenological models embedded in FEA analysis are part of common practice today in the development of devices made out of Nitinol. In vivo loading of medical devices has cyclic characteristics. There have been some indications in the literature that cyclic loading of Nitinol modifies substantially its behavior. A consortium of several stent manufacturers, Safe Technology and Dassault Systèmes Simulia Corp., dedicated to the developm