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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

JOURNAL OF STRUCTURAL ENGINEERING / JANUARY 2001 / 3 MODELING SHEAR BEHAVIOR OF HYBRID RCS  

E-print Network

JOURNAL OF STRUCTURAL ENGINEERING / JANUARY 2001 / 3 MODELING SHEAR BEHAVIOR OF HYBRID RCS BEAM columns and steel (RCS) beams is presented. Based on a preestablished maximum attainable joint shear deformation, design equations were developed for use in both interior and exterior RCS connections

Parra-Montesinos, Gustavo J.

3

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

4

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

5

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

6

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

USGS Publications Warehouse

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

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

2000-01-01

7

Modeling the nuclear magnetic resonance behavior of lung: from electrical engineering to critical care medicine.  

PubMed

The present article reviews the basic principles of a new approach to the characterization of pulmonary disease. This approach is based on the unique nuclear magnetic resonance (NMR) properties of the lung and combines experimental measurements (using specially developed NMR techniques) with theoretical simulations. The NMR signal from inflated lungs decays very rapidly compared with the signal from completely collapsed (airless) lungs. This phenomenon is due to the presence of internal magnetic field inhomogeneity produced by the alveolar air-tissue interface (because air and water have different magnetic susceptibilities). The air-tissue interface effects can be detected and quantified by magnetic resonance imaging (MRI) techniques using temporally symmetric and asymmetric spin-echo sequences. Theoretical models developed to explain the internal (tissue-induced) magnetic field inhomogeneity in aerated lungs predict the NMR lung behavior as a function of various technical and physiological factors (e.g., the level of lung inflation) and simulate the effects of various lung disorders (in particular, pulmonary edema) on this behavior. Good agreement has been observed between the predictions obtained from the mathematical models and the results of experimental NMR measurements in normal and diseased lungs. Our theoretical and experimental data have important pathophysiological and clinical implications, especially with respect to the characterization of acute lung disease (e.g., pulmonary edema) and the management of critically ill patients. PMID:10334720

Cutillo, A G; Ailion, D C

1999-01-01

8

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

9

Modeling Long-Term Search Engine Usage  

Microsoft Academic Search

Search engines are key components in the online world and the choice of search engine is an important determinant of the user experience. In this work we seek to model user behaviors and determine key variables that af- fect search engine usage. In particular, we study the engine usage behavior of more than ten thousand users over a period of

Ryen W. White; Ashish Kapoor; Susan T. Dumais

2010-01-01

10

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

Microsoft Academic Search

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

Chuan He

1996-01-01

11

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

E-print Network

by wrapping multiple layers of Kevlar 49 around a thin aluminum encasement. The fabric is then covered that there is no mechanistic based constitutive model for woven Kevlar 49 or any other fabric, especially one that can be used significant importance in the design of fan-containment systems. Currently, Kevlar is the only fabric approved

Mobasher, Barzin

12

Relation of Contextual Supports and Barriers to Choice Behavior in Engineering Majors: Test of Alternative Social Cognitive Models  

ERIC Educational Resources Information Center

Social cognitive career theory (SCCT; R. W. Lent, S. D. Brown, and G. Hackett, 1994) and general social cognitive theory (Bandura, 1999, 2000) posit somewhat different relations between contextual variables and choice actions. The authors tested the predictions of these 2 model variations. Participants (328 students in an introductory engineering

Lent, Robert W.; Brown, Steven D.; Schmidt, Janet; Brenner, Bradley; Lyons, Heather; Treistman, Dana

2003-01-01

13

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

14

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

15

Space shuttle main engine model identification  

Microsoft Academic Search

System identification techniques are used to represent the dynamic behavior of the SSME (space shuttle main engine). The comparison of the responses of a nonlinear simulation with the responses of an identified model indicates very good agreement. The identified model can be used for control design purposes. The identified model does not include valve linkage backlash and valve stiction nonlinearities.

A. Duyar; T.-H. Guo; W. C. Merrill

1990-01-01

16

Collective Modeling of Human Social Behavior Danny Wyatt  

E-print Network

Collective Modeling of Human Social Behavior Danny Wyatt Dept. of Computer Science and Engineering taking into account the structure of their social ties. I believe that collective behavior modeling will provide new insights into the relationship between local in- dividual behavior and global social structure

Anderson, Richard

17

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

18

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

19

COMPUTATIONAL MODELS FOR CIVIL ENGINEERING  

E-print Network

#12;COMPUTATIONAL MODELS FOR CIVIL ENGINEERING Constantin Ionescu, Alex Horia Brbat, Rodian;Proceedings of the Sixth International Symposium " Computational Civil Engineering 2008" Iai, Romania, May 30, 2008 Descrierea CIP a Bibliotecii Naionale a României Computational models for civil engineering / ed

Fernandez, Thomas

20

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

21

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

22

Frameworks and Models in Engineering Systems / Engineering System Design  

NSDL National Science Digital Library

This class, created by Prof. Joseph Sussman of the Massachusetts Institute of Technology, provides an introduction to quantitative models and qualitative frameworks for studying complex engineering systems. Also taught is the art of abstracting a complex system into a model for purposes of analysis and design while dealing with complexity, emergent behavior, stochasticity, non-linearities and the requirements of many stakeholders with divergent objectives. The successful completion of the class requires a semester-long class project that deals with critical contemporary issues which require an integrative, interdisciplinary approach using the above models and frameworks.

Sussman, Joseph

23

Surface Engineering of Liposomes for Stealth Behavior  

PubMed Central

Liposomes are used as a delivery vehicle for drug molecules and imaging agents. The major impetus in their biomedical applications comes from the ability to prolong their circulation half-life after administration. Conventional liposomes are easily recognized by the mononuclear phagocyte system and are rapidly cleared from the blood stream. Modification of the liposomal surface with hydrophilic polymers delays the elimination process by endowing them with stealth properties. In recent times, the development of various materials for surface engineering of liposomes and other nanomaterials has made remarkable progress. Poly(ethylene glycol)-linked phospholipids (PEG-PLs) are the best representatives of such materials. Although PEG-PLs have served the formulation scientists amazingly well, closer scrutiny has uncovered a few shortcomings, especially pertaining to immunogenicity and pharmaceutical characteristics (drug loading, targeting, etc.) of PEG. On the other hand, researchers have also begun questioning the biological behavior of the phospholipid portion in PEG-PLs. Consequently, stealth lipopolymers consisting of non-phospholipids and PEG-alternatives are being developed. These novel lipopolymers offer the potential advantages of structural versatility, reduced complement activation, greater stability, flexible handling and storage procedures and low cost. In this article, we review the materials available as alternatives to PEG and PEG-lipopolymers for effective surface modification of liposomes. PMID:24300562

Nag, Okhil K.; Awasthi, Vibhudutta

2013-01-01

24

COSYSMO: A Systems Engineering Cost Model  

E-print Network

Building on the synergy between systems engineering and software engineering, we have developed a parametric model to estimate systems engineering costs. The goal of this model called COSYSMO (Constructive Systems Engineering ...

Valerdi, Ricardo

25

Rocket engine diagnostics using qualitative modeling techniques  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

26

Rocket engine diagnostics using qualitative modeling techniques  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

27

IUTAM Symposium on Multiscale Modeling and Characterization of Elastic-Inelastic Behavior of Engineering Materials : proceedings of the IUTAM Symposium held in Marrakech, Morocco, 20-25 October, 2002. Solid Mechanics and its Applications  

SciTech Connect

The papers in this proceeding are a collection of the works presented at the IUTAM symposium-Marrakech 2002 (October 20-25) which brought together scientists from various countries. These papers cover contemporary topics in multiscale modeling and characterization of materials behavior of engineering materials. They were selected to focus on topics related to deformation and failure in metals, alloys, intermetallics and polymers including: experimental techniques, deformation and failure mechanisms, dislocation-based modeling, microscopic-macroscopic averaging schemes, application to forming processes and to phase transformation, localization and failure phenomena, and computational advances.

Ahzi, Said; Cherkaoui, Mohammed; Khaleel, Mohammad A.; Zbib, Hussein M.; Zikry, M A.; LaMatina, B

2004-03-01

28

Gas-turbine engine steady-state behavior  

Microsoft Academic Search

A set of graphics with explanations illustrating gas turbine engine steady state behavior are presented. Typical combinations of compressors and nozzles which occur in a gas turbine engine are shown. The basic effect of a nozzle is explained by considering a compressor on a test rig: typical compressor, fan, and turbine characteristics are illustrated. The following are discussed: the degrees

Barry Curnock

1993-01-01

29

Putting Performance Engineering into Model-Driven Engineering: Model-Driven Performance Engineering  

Microsoft Academic Search

Late identification of performance problems can lead to significant additional development costs. Hence, it is necessary to\\u000a address performance in several development phases by performing a performance engineering process. We show that Model-Driven\\u000a Engineering (MDE) specifics can be utilised for performance engineering. Therefore, we propose a process combining MDE and\\u000a performance engineering called Model-Driven Performance Engineering (MDPE).\\u000a \\u000a Additionally we present

Mathias Fritzsche; Jendrik Johannes

2007-01-01

30

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

31

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

32

IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS -FORMAL METHODS FOR EMBEDDED SYSTEMS DESIGN, NOVEMBER 2008 1 Formal Methods for Systems Engineering Behavior  

E-print Network

2008 1 Formal Methods for Systems Engineering Behavior Models Charlotte Seidner and Olivier H. Roux Abstract--Safety analysis in Systems Engineering (SE) pro- cesses, as usually implemented, rarely relies SYSTEMS Engineering (SE) is defined by the INCOSE1 as an "interdisciplinary approach" to perform

Paris-Sud XI, Université de

33

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

34

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

35

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

36

A behavioral model of writing  

Microsoft Academic Search

In this paper we propose a new model to generate handwriting based on behavioral patterns we believe is to be found in humans when imitating a written character. The proposed algorithm has a hierarchical structure. It is consisted of two main levels. At the first level the graphical features of the written letter to be imitated are extracted. These features

M. Naghibolhosseini; F. Bahrami

2008-01-01

37

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

38

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

39

Modeling of bubbly and slug flow behavior under microgravity conditions  

E-print Network

MODELING OF BUBBLY AND SLUG FLOW BEHAVIOR UNDER MICROGRAVITY CONDITIONS A Thesis by MATI'HIEU JEAN-SEBASTIEN LONGEOT Submitted to the Office of Graduate Studies of Texas AdtM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 1995 Major Subject: Nuclear Engineering MODELING OF BUBBLY AND SLUG FLOW BEHAVIOR UNDER MICROGRAVITY CONDITIONS A Thesis by MATIHIEU JEAN-SEBASTIEN LONGEOT Submitted to Texas A&M University in partial fulfillment...

Longeot, Matthieu Jean-Sebastien

2012-06-07

40

Engineered in vitro disease models.  

PubMed

The ultimate goal of most biomedical research is to gain greater insight into mechanisms of human disease or to develop new and improved therapies or diagnostics. Although great advances have been made in terms of developing disease models in animals, such as transgenic mice, many of these models fail to faithfully recapitulate the human condition. In addition, it is difficult to identify critical cellular and molecular contributors to disease or to vary them independently in whole-animal models. This challenge has attracted the interest of engineers, who have begun to collaborate with biologists to leverage recent advances in tissue engineering and microfabrication to develop novel in vitro models of disease. As these models are synthetic systems, specific molecular factors and individual cell types, including parenchymal cells, vascular cells, and immune cells, can be varied independently while simultaneously measuring system-level responses in real time. In this article, we provide some examples of these efforts, including engineered models of diseases of the heart, lung, intestine, liver, kidney, cartilage, skin and vascular, endocrine, musculoskeletal, and nervous systems, as well as models of infectious diseases and cancer. We also describe how engineered in vitro models can be combined with human inducible pluripotent stem cells to enable new insights into a broad variety of disease mechanisms, as well as provide a test bed for screening new therapies. PMID:25621660

Benam, Kambez H; Dauth, Stephanie; Hassell, Bryan; Herland, Anna; Jain, Abhishek; Jang, Kyung-Jin; Karalis, Katia; Kim, Hyun Jung; MacQueen, Luke; Mahmoodian, Roza; Musah, Samira; Torisawa, Yu-Suke; van der Meer, Andries D; Villenave, Remi; Yadid, Moran; Parker, Kevin K; Ingber, Donald E

2015-01-24

41

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

42

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

43

Behavioral/Cognitive Engineered Deafness Reveals That Mouse Courtship  

E-print Network

Behavioral/Cognitive Engineered Deafness Reveals That Mouse Courtship Vocalizations Do Not Require features of each syllable type emitted by hearing and deaf males in the presence of a female. We found that almost all of the vocalization features we examined were similar in hearing and deaf animals

Rubel, Edwin

44

A moderation model of political behavior  

Microsoft Academic Search

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

Liu Jun; Yu Guang-tao; Liu Gang

2009-01-01

45

Factors Associated With Risky Sun Exposure Behaviors Among Operating Engineers  

PubMed Central

Background The objective of this study was to determine the factors associated with sun exposure behaviors among Operating Engineers (heavy equipment operators). Methods Operating Engineers (N=498) were asked to complete a cross-sectional survey. Linear and logistic regression analyses were used to determine health behavior, perceptional, and demographic factors associated with sun exposure behavior (sun burns, blistering, use of sunscreen, and interest in sun protection services). Results Almost half reported 2 or more sunburns/summer and the median times blistering was 2 with a range of 0–100. About one-third never used sun block while just over one-third rarely used sun block. Almost one-quarter were interested in sun protection guidance. Multivariate analyses showed that perceptions of skin type, alcohol problems, fruit intake, BMI, sleep quality, age, sex, and race were significantly associated with at least one of the outcome variables (p<.05). Conclusions Operating Engineers are at high risk for skin cancer due to high rates of exposure to UV light and low rates of sun block. Subgroups of Operating Engineers are particularly at risk for sun damage. Interventions are needed to decrease sun exposure among Operating Engineers. PMID:22692974

Duffy, Sonia A.; Choi, Seung Hee; Hollern, Rachael; Ronis, David L.

2012-01-01

46

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

47

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.

48

ASSISTANT PROFESSOR OF MECHANICAL ENGINEERING COMPUTATIONAL MODELING  

E-print Network

letter clearly indicating how their computational modeling research fits into the department, curriculumASSISTANT PROFESSOR OF MECHANICAL ENGINEERING COMPUTATIONAL MODELING COLLEGE OF ENGINEERING-track faculty position at the level of assistant professor. This position requires candidates with research

49

Perceptual Modeling for Behavioral Animation of Fishes  

E-print Network

Perceptual Modeling for Behavioral Animation of Fishes Xiaoyuan Tu Demetri Terzopoulos Department of animal behavior by autonomous animate agents re­ quires that the agents able to perceive their virtual by the animator. Simple autonomous models emerged as researchers began to introduce behavioral components

Toronto, University of

50

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

51

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.

52

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

53

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

54

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

55

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

56

Adaptive Behavioral Modeling for Crowd Simulations  

Microsoft Academic Search

In this study, we design an adaptive behavioral model for a dynamic virtual environment. We model the dynamic environment with behavior maps which are constructed with information theory quantities. These maps are capable of capturing the dynamic nature of the environment by changing temporally and spatially. Subsequent to building this model, agents' responses to these maps are represented with a

Cagatay Turkay; Emre Koc; Kamer Yuksel; Selim Balcisoy

57

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

58

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

59

Approximate dynamic model of a turbojet engine  

NASA Technical Reports Server (NTRS)

An approximate dynamic nonlinear model of a turbojet engine is elaborated on as a tool in studying the aircraft control loop, with the turbojet engine treated as an actuating component. Approximate relationships linking the basic engine parameters and shaft speed are derived to simplify the problem, and to aid in constructing an approximate nonlinear dynamic model of turbojet engine performance useful for predicting aircraft motion.

Artemov, O. A.

1978-01-01

60

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

61

Improved hybrid wavelet neural network methodology for time-varying behavior prediction of engineering structures  

Microsoft Academic Search

An improved neuro-wavelet modeling (NWM) methodology is presented, and it aims at improving prediction precision of time-varying\\u000a behavior of engineering structures. The proposed methodology distinguishes from the existing NWM methodology by featuring\\u000a the distinctive capabilities of constructing optimally uncoupled dynamic subsystems in light of the redundant Haar wavelet\\u000a transform (RHWT) and optimizing neural network. In particular, two techniques of imitating

Maosen Cao; Pizhong Qiao; Qingwen Ren

2009-01-01

62

Modelling Retail Customer Behavior at Merrill Lynch  

Microsoft Academic Search

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

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

1982-01-01

63

Oscillating behavior within the social force model  

E-print Network

The social force model belongs to a class of microscopic force-based pedestrian model for which the interaction with the neighbors solely depends on the distance spacings. Yet, distance based models can lead to unrealistic oscillating behaviors with collision and negative peed (especially in 1D scenarios. With appropriate approximations we analyze the behavior of a simplified force-based model and show that with "realistic" parameter values the system oscillates.

Chraibi, Mohcine

2014-01-01

64

Applying the Health Belief Model to college students' health behavior  

PubMed Central

The purpose of this research was to investigate how university students' nutrition beliefs influence their health behavioral intention. This study used an online survey engine (Qulatrics.com) to collect data from college students. Out of 253 questionnaires collected, 251 questionnaires (99.2%) were used for the statistical analysis. Confirmatory Factor Analysis (CFA) revealed that six dimensions, "Nutrition Confidence," "Susceptibility," "Severity," "Barrier," "Benefit," "Behavioral Intention to Eat Healthy Food," and "Behavioral Intention to do Physical Activity," had construct validity; Cronbach's alpha coefficient and composite reliabilities were tested for item reliability. The results validate that objective nutrition knowledge was a good predictor of college students' nutrition confidence. The results also clearly showed that two direct measures were significant predictors of behavioral intentions as hypothesized. Perceived benefit of eating healthy food and perceived barrier for eat healthy food to had significant effects on Behavioral Intentions and was a valid measurement to use to determine Behavioral Intentions. These findings can enhance the extant literature on the universal applicability of the model and serve as useful references for further investigations of the validity of the model within other health care or foodservice settings and for other health behavioral categories. PMID:23346306

Kim, Hak-Seon; Ahn, Joo

2012-01-01

65

Reverse engineering of geometric models - an introduction  

Microsoft Academic Search

ABSTRACT IN MANY AREAS OF INDUSTRY, IT IS DESIRABLE TO CREATE GEOMETRIC MODELS OF EXISTING OB JECTS FOR WHICH NO SUCH MODEL IS AVAILABLE. THIS PAPER REVIEWS THE PROCESS OF REVERSE ENGINEERING OF SHAPES. AFTER IDENTIFYING THE PURPOSE OF REVERSE ENGINEERING AND THE MAIN APPLICATION AREAS, THE MOST IMPORTANT ALGORITHMIC STEPS ARE OUTLINED AND VARIOUS RECONSTRUCTION STRATEGIES ARE PRE-SENTED. PROS

Tamás Várady; Ralph R. Martin; Jordan Cox

1997-01-01

66

Biosocial Models of Deviant Behavior.  

ERIC Educational Resources Information Center

Describes biological influences on criminality. Illustrative data suggest a biological sex difference in criminality and heritable differences in this trait among individuals. Methods of isolating environmental influences are described. Author notes that using environment-friendly behavior genetic research designs is not only proper but would…

Rowe, David C.

1995-01-01

67

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

68

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

69

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

70

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

71

A systemic model of doping behavior.  

PubMed

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

Johnson, Michael B

2011-01-01

72

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

73

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

74

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

Federal Register 2010, 2011, 2012, 2013

...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

75

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

76

Behavioral phenotyping of mouse models of neurodegeneration.  

PubMed

Neurodegenerative disorders, such as amyotrophic lateral sclerosis (ALS), Huntington's (HD), Parkinson's (PD) and Alzheimer's diseases (AD), are characterized by the loss of structure and function of specific neuronal circuitry in the brain. As a result of this loss, behavioral symptoms occur progressively. Understanding the causes of neurodegeneration is fundamental for the development of new therapeutic targets. For this purpose, several animal models of neurodegenerative disorders have been generated and characterized. During the characterization, behavioral science plays a crucial role by identifying specific symptoms in these animal models of human disorders. Later on, it also allows scientists to verify the efficacy of new treatments. This chapter describes some of the standard tests used to assess behavioral symptoms present in mouse models of neurodegenerative disorders. A list of procedures is provided to evaluate motor skills for the study of ALS, HD, and PD models, and to evaluate spatial learning and memory for the study of AD models. PMID:21913104

Dumont, Magali

2011-01-01

77

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

78

Engineering of Framework-Specific Modeling Languages  

Microsoft Academic Search

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

Michal Antkiewicz; Krzysztof Czarnecki; Matthew Stephan

2009-01-01

79

76 FR 54373 - Airworthiness Directives; Austro Engine GmbH Model E4 Diesel Piston Engines  

Federal Register 2010, 2011, 2012, 2013

...Austro Engine GmbH Model E4 Diesel Piston Engines AGENCY: Federal Aviation...will affect about 32 model E4 diesel piston engines, installed on airplanes of...Austro Engine GmbH model E4 diesel piston engines, with high-pressure...

2011-09-01

80

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

81

An Assembly Process Model for Method Engineering  

Microsoft Academic Search

The need for a better productivity of system engineering teams, as well as a better quality of products motivates the development of solutions to adapt methods to the project situation at hand. This is known as situational method engineering. In this paper we propose a generic process model to support the construction of a new method by assembling method chunks

Jolita Ralyté; Colette Rolland

2001-01-01

82

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

83

Systems Engineering Group 1/19 Simulating blocking behavior of manufacory lines  

E-print Network

13 Systems Engineering Group 1/19 Simulating blocking behavior of manufacory lines Backwave: From for ... Simulation Results 13 Systems Engineering Group 2/19 DEM Results of the simulation #12;DEM Introduction of flux: ... Questions? Heuristics for ... Simulation Results 13 Systems Engineering Group 3

Ringhofer, Christian

84

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

85

FACULTY POSITION IN MODEL-BASED SYSTEMS ENGINEERING  

E-print Network

FACULTY POSITION IN MODEL-BASED SYSTEMS ENGINEERING The Institute for Systems Research (ISR systems engineering, advise systems engineering students for their theses, and develop new systems $20M, it conducts interdisciplinary research and provides education in systems engineering

Bohnhoff, David

86

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

87

Explaining clinical behaviors using multiple theoretical models  

PubMed Central

Background In the field of implementation research, there is an increased interest in use of theory when designing implementation research studies involving behavior change. In 2003, we initiated a series of five studies to establish a scientific rationale for interventions to translate research findings into clinical practice by exploring the performance of a number of different, commonly used, overlapping behavioral theories and models. We reflect on the strengths and weaknesses of the methods, the performance of the theories, and consider where these methods sit alongside the range of methods for studying healthcare professional behavior change. Methods These were five studies of the theory-based cognitions and clinical behaviors (taking dental radiographs, performing dental restorations, placing fissure sealants, managing upper respiratory tract infections without prescribing antibiotics, managing low back pain without ordering lumbar spine x-rays) of random samples of primary care dentists and physicians. Measures were derived for the explanatory theoretical constructs in the Theory of Planned Behavior (TPB), Social Cognitive Theory (SCT), and Illness Representations specified by the Common Sense Self Regulation Model (CSSRM). We constructed self-report measures of two constructs from Learning Theory (LT), a measure of Implementation Intentions (II), and the Precaution Adoption Process. We collected data on theory-based cognitions (explanatory measures) and two interim outcome measures (stated behavioral intention and simulated behavior) by postal questionnaire survey during the 12-month period to which objective measures of behavior (collected from routine administrative sources) were related. Planned analyses explored the predictive value of theories in explaining variance in intention, behavioral simulation and behavior. Results Response rates across the five surveys ranged from 21% to 48%; we achieved the target sample size for three of the five surveys. For the predictor variables, the mean construct scores were above the mid-point on the scale with median values across the five behaviors generally being above four out of seven and the range being from 1.53 to 6.01. Across all of the theories, the highest proportion of the variance explained was always for intention and the lowest was for behavior. The Knowledge-Attitudes-Behavior Model performed poorly across all behaviors and dependent variables; CSSRM also performed poorly. For TPB, SCT, II, and LT across the five behaviors, we predicted median R2 of 25% to 42.6% for intention, 6.2% to 16% for behavioral simulation, and 2.4% to 6.3% for behavior. Conclusions We operationalized multiple theories measuring across five behaviors. Continuing challenges that emerge from our work are: better specification of behaviors, better operationalization of theories; how best to appropriately extend the range of theories; further assessment of the value of theories in different settings and groups; exploring the implications of these methods for the management of chronic diseases; and moving to experimental designs to allow an understanding of behavior change. PMID:23075284

2012-01-01

88

COLLEGE OF ENGINEERING AND APPLIED SCIENCES Social and Behavioral Sciences/Humanities Categories  

E-print Network

COLLEGE OF ENGINEERING AND APPLIED SCIENCES Social and Behavioral Sciences/Humanities Categories requirements must select one with a humanities designator and one with a social and behavioral sciences designator. Social and Behavioral Sciences AAS Courses 201, 216, 219, 330, 338, 339, 340, 341, 345, 348, 351

Ge, Qiaode Jeff

89

Application modeling using reverse engineering techniques  

Microsoft Academic Search

In this work we present techniques and tools that enable effective reverse engineering procedures for web applications that were developed using the promising ASP.NET technology. We deal with model-driven development in its reverse aspect by implementing reverse engineering methods. Our implemented methods model web applications using a well-known, web oriented and robust language, namely WebML. This is, to the authors'

T. Katsimpa; Yannis Panagis; Evangelos Sakkopoulos; Giannis Tzimas; Athanasios K. Tsakalidis

2006-01-01

90

Analysis of bending behavior of native and engineered auricular and costal cartilage.  

PubMed

A large-deflection elasticity model was used to describe the mechanical behavior of cartilaginous tissues during three-point bending tests. Force-deflection curves were measured for 20-mm long x 4-mm wide x approximately 1-mm thick strips of porcine auricular and costal cartilage. Using a least-squares method with elastic modulus in bending as the only adjustable parameter, data were fit to a model based on the von Karman theory for large deflection of plates. This model described the data well, with an average RMS error of 14.8% and an average R(2) value of 0.98. Using this method, the bending modulus of auricular cartilage (4.6 MPa) was found to be statistically lower (p < 0.05) than that of costal cartilage (7.1 MPa). Material features of the cartilage samples influenced the mechanical behavior, including the orientation of the perichondrium in auricular cartilage. These methods also were used to determine the elastic moduli of engineered cartilage samples produced by seeding chondrocytes into fibrin glue. The modulus of tissue-engineered constructs increased statistically with time (p < 0.05), but still were statistically lower than the moduli of the native tissue samples (p > 0.05), reaching only about a third of the values of native samples. PMID:14986315

Roy, Rani; Kohles, Sean S; Zaporojan, Victor; Peretti, Giuseppe M; Randolph, Mark A; Xu, Jianwei; Bonassar, Lawrence J

2004-03-15

91

Effect of surface impulsive thermal loads on fatigue behavior of constant volume propulsion engine combustor materials  

Microsoft Academic Search

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

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

2004-01-01

92

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.

2009-12-10

93

Modal Test Experiences with a Jet Engine Fan Model  

NASA Astrophysics Data System (ADS)

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 dynamic behavior is sensitive to small perturbations. Another problem is that multiple inputs and high-resolution techniques are required to separate modes that are nearly repeated. Two studies of engine blade response were recently completed in which bench modal tests were successfully performed on simplified fan models. The modal test procedures for the first study were successful in extracting the modal parameters. But the tests in the second study were more demanding. Ultimately, an approach was devised that accurately extracted the modal parameters. This paper describes the challenges and the evolution of the test procedures.

HOLLKAMP, J. J.; GORDON, R. W.

2001-11-01

94

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

95

Facilitating Communication with Open Learner Models: A Semiotic Engineering Perspective  

E-print Network

Facilitating Communication with Open Learner Models: A Semiotic Engineering Perspective Peter as a facilitator of communication from a semiotic engineering perspective. Keywords: Open learner models gives an overview of OLM communication in school contexts. Semiotic engineering is then suggested

Bull, Susan

96

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

97

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

98

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

99

Behavior Modeling with Probabilistic Context Free Grammars  

Microsoft Academic Search

Identifying the behavioral patterns in a social network setting is beneficial to understand how people behave in certain application domains. Such pat- terns can also be utilized to characterize social signals such as social roles from interactions. In this work, we examine how probabilistic context free grammars (PCFGs) can be utilized to model interactions and role taking in a social

Sahin Cem Geyik; Jierui Xie; Boleslaw K. Szymanski

2010-01-01

100

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

101

Modeling mechanical behavior of epoxy-shape memory polymers  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

102

Performance Engineering in the Community Atmosphere Model  

SciTech Connect

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

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

2006-05-30

103

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

104

Discrete time modelization of human pilot behavior  

NASA Technical Reports Server (NTRS)

This modelization starts from the following hypotheses: pilot's behavior is a time discrete process, he can perform only one task at a time and his operating mode depends on the considered flight subphase. Pilot's behavior was observed using an electro oculometer and a simulator cockpit. A FORTRAN program has been elaborated using two strategies. The first one is a Markovian process in which the successive instrument readings are governed by a matrix of conditional probabilities. In the second one, strategy is an heuristic process and the concepts of mental load and performance are described. The results of the two aspects have been compared with simulation data.

Cavalli, D.; Soulatges, D.

1975-01-01

105

Sharing Research Models: Using Software Engineering Practices for Facilitation  

PubMed Central

Increasingly, researchers are turning to computational models to understand the interplay of important variables on systems’ behaviors. Although researchers may develop models that meet the needs of their investigation, application limitations—such as nonintuitive user interface features and data input specifications—may limit the sharing of these tools with other research groups. By removing these barriers, other research groups that perform related work can leverage these work products to expedite their own investigations. The use of software engineering practices can enable managed application production and shared research artifacts among multiple research groups by promoting consistent models, reducing redundant effort, encouraging rigorous peer review, and facilitating research collaborations that are supported by a common toolset. This report discusses three established software engineering practices— the iterative software development process, object-oriented methodology, and Unified Modeling Language—and the applicability of these practices to computational model development. Our efforts to modify the MIDAS TranStat application to make it more user-friendly are presented as an example of how computational models that are based on research and developed using software engineering practices can benefit a broader audience of researchers. PMID:21687780

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

2011-01-01

106

Modeling irrigation behavior in groundwater systems  

NASA Astrophysics Data System (ADS)

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

107

Modeling structural dynamic behavior of SSME components  

NASA Technical Reports Server (NTRS)

FEM studies are presented of the nozzle and the low-pressure fuel-pump inducer designs for the Space Shuttle Main Engine (SSME) to analyze the effects of structural vibrations. FEM preprocessing software based on a CAD system is employed to develop a model of the component's sophisticated geometry. The nozzle geometry is also defined by means of the preprocessing technique and subsequently analyzed with respect to time-transient loading. The analysis is conducted with a Cray supercomputer using the SPAR/EAL FEM program. The investigation of the nozzle demonstrates the advantageous use of symmetry in the determination of nozzle response to SSME start-up transients. Plots of time vs strain are developed for gages on the nozzle wall and steerhorn tubing. The results of the inducer modeling are found to be adequate for investigating the component's principle modes, and the nozzle results indicate the suitability of the FEM techniques for optimizing the design of engine components.

Kiefling, Larry A.; Saxon, J. B.; Prickett, T. L.

1991-01-01

108

Statistical and engineering methods for model enhancement  

NASA Astrophysics Data System (ADS)

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

Chang, Chia-Jung

109

Chain modeling for life cycle systems engineering  

SciTech Connect

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

Rivera, J.J. [Sandia National Lab., Albuquerque, NM (United States); Shapiro, V. [Univ. of Wisconsin, Madison, WI (United States). Spatial Automation Lab.

1997-12-01

110

Usefulness of Behavioral and Electrophysiological Studies in Transgenic Models of Alzheimer's Disease  

Microsoft Academic Search

Over the past several years researchers have engineered many transgenic models of Alzheimer's disease. Since loss of memory is one of the major hallmarks of the disorder, the phenotypic characterization of these animals has included both behavioral tests which aim to evaluate learning abilities, and electrophysiological studies to analyze synaptic transmission and long-term potentiation, a widely studied cellular model of

Antonino Sant'Angelo; Fabrizio Trinchese; Ottavio Arancio

2003-01-01

111

Bayesian Network Modeling of Offender Behavior for Criminal Profiling Kelli Crews Baumgartner, Silvia Ferrari, and C. Gabrielle Salfati  

E-print Network

, Silvia Ferrari, and C. Gabrielle Salfati Abstract-- A Bayesian network (BN) model of criminal behavior. Ferrari is with Faculty of Mechanical Engineering at Duke University, Durham, NC 27707, USA sferrari

Ferrari, Silvia

112

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

113

THE CONSTRUCTIVE SYSTEMS ENGINEERING COST MODEL (COSYSMO) Ricardo Valerdi  

E-print Network

THE CONSTRUCTIVE SYSTEMS ENGINEERING COST MODEL (COSYSMO) by Ricardo Valerdi A Dissertation of the Requirements for the Degree DOCTOR OF PHILOSOPHY (INDUSTRIAL AND SYSTEMS ENGINEERING) August 2005 Copyright Council on Systems Engineering (Corporate Advisory Board, Measurement Working Group, and Systems

de Weck, Olivier L.

114

Quasi-One-Dimensional Modeling of Pulse Detonation Rocket Engines  

NASA Technical Reports Server (NTRS)

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

Morris, Christopher I.

2003-01-01

115

Chevron Behavior and Isostable Enthalpic Barriers in Protein Folding: Successes and Limitations of Simple Goo-like Modeling  

E-print Network

. Computationally, it is not yet feasible to ascertain the chevron behaviors of high-resolution atomic modelsChevron Behavior and Isostable Enthalpic Barriers in Protein Folding: Successes and Limitations of Simple Goo-like Modeling Hu¨seyin Kaya, Zhirong Liu, and Hue Sun Chan Protein Engineering Network

Chan, Hue Sun

116

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

117

An RL10A-3-3A rocket engine model using the rocket engine transient simulator (ROCETS) software  

NASA Technical Reports Server (NTRS)

Steady-state and transient computer models of the RL10A-3-3A rocket engine have been created using the Rocket Engine Transient Simulation (ROCETS) code. These models were created for several purposes. The RL10 engine is a critical component of past, present, and future space missions; the model will give NASA an in-house capability to simulate the performance of the engine under various operating conditions and mission profiles. The RL10 simulation activity is also an opportunity to further validate the ROCETS program. The ROCETS code is an important tool for modeling rocket engine systems at NASA Lewis. ROCETS provides a modular and general framework for simulating the steady-state and transient behavior of any desired propulsion system. Although the ROCETS code is being used in a number of different analysis and design projects within NASA, it has not been extensively validated for any system using actual test data. The RL10A-3-3A has a ten year history of test and flight applications; it should provide sufficient data to validate the ROCETS program capability. The ROCETS models of the RL10 system were created using design information provided by Pratt & Whitney, the engine manufacturer. These models are in the process of being validated using test-stand and flight data. This paper includes a brief description of the models and comparison of preliminary simulation output against flight and test-stand data.

Binder, Michael

1993-01-01

118

Analysis of the Transtheoretical Model of Behavior Change  

Microsoft Academic Search

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

James A. Lenio

119

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

120

Qualitative models for space system engineering  

NASA Technical Reports Server (NTRS)

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

Forbus, Kenneth D.

1990-01-01

121

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

122

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

123

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

124

Large Time Behavior of Nonlocal Aggregation Models with Nonlinear Diffusion  

E-print Network

Large Time Behavior of Nonlocal Aggregation Models with Nonlinear Diffusion Martin Burger Marco Di for convenience. Keywords: Nonlinear diffusion, nonlocal PDEs, biological aggregation, stationary solutions time behavior of nonlocal models for aggregation, including the possible presence of nonlinear

Di Francesco, Marco

125

A stirling engine computer model for performance calculations  

NASA Technical Reports Server (NTRS)

To support the development of the Stirling engine as a possible alternative to the automobile spark-ignition engine, the thermodynamic characteristics of the Stirling engine were analyzed and modeled on a computer. The modeling techniques used are presented. The performance of an existing rhombic-drive Stirling engine was simulated by use of this computer program, and some typical results are presented. Engine tests are planned in order to evaluate this model.

Tew, R.; Jefferies, K.; Miao, D.

1978-01-01

126

Physical Modeling of Turbocharged Engines and Parameter Identification  

Microsoft Academic Search

\\u000a The common theme in this chapter is physical modeling of engines and the subjects touch three topics in nonlinear engine models\\u000a and parameter identification. First, a modeling methodology is described. It focuses on the gas and energy flows in engines\\u000a and covers turbocharged engines. Examples are given where the methodology has been successfully applied, covering naturally\\u000a aspirated engines and both

Lars Eriksson; Johan Wahlström; Markus Klein

127

FUZZY MODELLING AND CONTROL OF MARINE DIESEL ENGINE PROCESS  

Microsoft Academic Search

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

Radovan Antonic

128

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

129

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

130

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

131

Elastic behavior of corrugated cardboard: Experiments and Modeling Z. ABOURAa *  

E-print Network

1 Elastic behavior of corrugated cardboard: Experiments and Modeling Z. ABOURAa * , N. TALBIb , S cardboard behavior, an analytical model related to the assessment of equals behavior is proposed. This model takes into account the geometrical and mechanical properties of the corrugated cardboard constituents

Paris-Sud XI, Université de

132

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

133

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

134

Voraussetzungen: Control Systems I & II, System Modeling, Engine Class (IC Engines and Propulsion Systems,  

E-print Network

Systems, Introduction to Modeling and Control of Internal Combustion Engine Systems,...), MATLAB Design for a Novel Engine Concept Position Control for an Internal Combustion Engine (Simulation) German. The control task is to make an internal combustion engine piston follow a reference position trajectory

Lygeros, John

135

Molecular Modeling of Solid Fluid Phase Behavior  

SciTech Connect

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

Peter A. Monson

2007-12-20

136

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

137

Modeling cancer using genetically engineered mice.  

PubMed

Genetically engineered mouse (GEM) models have proven to be a powerful tool to study tumorigenesis. The mouse is the preferred complex organism used in cancer studies due to the high number and versatility of genetic tools available for this species. GEM models can mimic point mutations, gene amplifications, short and large deletions, translocations, etc.; thus, most of the genetic aberrations found in human tumors can be modeled in GEM, making GEM models a very attractive system. Furthermore, recent developments in mouse genetics may facilitate the generation of GEM models with increased mutational complexity, therefore resembling human tumors better. Within this review, we will discuss the different possibilities of modeling tumorigenesis using GEM and the future developments within the field. PMID:25636462

Stiedl, Patricia; Grabner, Beatrice; Zboray, Katalin; Bogner, Edith; Casanova, Emilio

2015-01-01

138

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

ERIC Educational Resources Information Center

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

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

2011-01-01

139

3D Engineered Models for Construction Support & Available Tools  

E-print Network

3D Engineered Models for Construction Support & Available Tools #12;3D Engineered Models for Construction · New web page www.fhwa.dot.gov/3d (search "fhwa 3D") ­ Specs, Standards, Details, Tech Briefs ­ Provides initial response within 24 hours of inquiry National Website and TSSC 2 #12;3D Engineered Models

140

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

141

A Compositional Knowledge Level Process Model of Requirements Engineering*  

E-print Network

1 A Compositional Knowledge Level Process Model of Requirements Engineering* Daniela E. Herlea 1,treur,niek}@cs.vu.nl Abstract. In current literature few detailed process models for Requirements Engineering are presented. In this paper the process of Requirements Engineering has been analyzed using knowledge-level modelling

Treur, Jan

142

Modelling the Design Process in Engineering and in Architecture  

Microsoft Academic Search

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

NIGEL CROSS; NORBERT ROOZENBURG

1992-01-01

143

Loss terms in free-piston Stirling engine models  

Microsoft Academic Search

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

Lloyd B. Gordon

1992-01-01

144

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

145

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

146

Animal Models for Bone Tissue Engineering Purposes  

Microsoft Academic Search

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

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

147

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

148

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

149

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

150

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

151

A REVIEW OF HYDRODYNAMICAL MODELS FOR SEMICONDUCTORS: ASYMPTOTIC BEHAVIOR  

E-print Network

A REVIEW OF HYDRODYNAMICAL MODELS FOR SEMICONDUCTORS: ASYMPTOTIC BEHAVIOR Hailiang Li , Peter results on the hydrodynamical model for semiconductors. The derivation of the mathematical model from on spatially bounded domain or whole space. Key words: Hydrodynamical models, semiconductors, asymptotic

Markowich, Peter A.

152

A REVIEW OF HYDRODYNAMICAL MODELS FOR SEMICONDUCTORS: ASYMPTOTIC BEHAVIOR  

E-print Network

A REVIEW OF HYDRODYNAMICAL MODELS FOR SEMICONDUCTORS: ASYMPTOTIC BEHAVIOR Hailiang Li # , Peter results on the hydrodynamical model for semiconductors. The derivation of the mathematical model from on spatially bounded domain or whole space. Key words: Hydrodynamical models, semiconductors, asymptotic

Markowich, Peter A.

153

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

154

Friction model of a marine diesel engine piston assembly  

Microsoft Academic Search

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

George A. Livanos; Nikolaos P. Kyrtatos

2007-01-01

155

Dynamic Models for Liquid Rocket Engines with Health Monitoring Application  

E-print Network

for liquid rocket engines are developed. The particular case of the Space Shuttle Main Engine (SSMEDynamic Models for Liquid Rocket Engines with Health Monitoring Application by Paulo César Lozano Engineering (1993) Instituto Tecnológico y de Estudios Superiores de Monterrey, México Submitted

156

Reverse Audio Engineering: Model-Based Inversion of Dynamic Range  

E-print Network

1 Reverse Audio Engineering: Model-Based Inversion of Dynamic Range Compression Stanislaw Gorlow, Graduate Student Member, IEEE and Joshua D. Reiss, Member, IEEE Abstract--Reverse audio engineering so far, reverse audio engineering. I. INTRODUCTION SOUND or audio engineering is an established discipline

157

Deriving Framework Usages Based on Behavioral Models  

NASA Astrophysics Data System (ADS)

One of the critical issue in framework-based software development is a huge introduction cost caused by technical gap between developers and users of frameworks. This paper proposes a technique for deriving framework usages to implement a given requirements specification. By using the derived usages, the users can use the frameworks without understanding the framework in detail. Requirements specifications which describe definite behavioral requirements cannot be related to frameworks in as-is since the frameworks do not have definite control structure so that the users can customize them to suit given requirements specifications. To cope with this issue, a new technique based on satisfiability problems (SAT) is employed to derive the control structures of the framework model. In the proposed technique, requirements specifications and frameworks are modeled based on Labeled Transition Systems (LTSs) with branch conditions represented by predicates. Truth assignments of the branch conditions in the framework models are not given initially for representing the customizable control structure. The derivation of truth assignments of the branch conditions is regarded as the SAT by assuming relations between termination states of the requirements specification model and ones of the framework model. This derivation technique is incorporated into a technique we have proposed previously for relating actions of requirements specifications to ones of frameworks. Furthermore, this paper discuss a case study of typical use cases in e-commerce systems.

Zenmyo, Teruyoshi; Kobayashi, Takashi; Saeki, Motoshi

158

Learning-Based Modeling of Multimodal Behaviors for Humanlike Robots  

E-print Network

Robot behaviors Cognitive Processes C S GeGa Figure 1: We used a learning-based approach to model howLearning-Based Modeling of Multimodal Behaviors for Humanlike Robots Chien-Ming Huang and Bilge in a natural and effec- tive manner, humanlike robots must seamlessly integrate behaviors across multiple

Mutlu, Bilge

159

LEADER - An integrated engine behavior and design analyses based real-time fault diagnostic expert system for Space Shuttle Main Engine (SSME)  

NASA Technical Reports Server (NTRS)

The LEADER expert system has been developed for automatic learning tasks encompassing real-time detection, identification, verification, and correction of anomalous propulsion system operations, using a set of sensors to monitor engine component performance to ascertain anomalies in engine dynamics and behavior. Two diagnostic approaches are embodied in LEADER's architecture: (1) learning and identifying engine behavior patterns to generate novel hypotheses about possible abnormalities, and (2) the direction of engine sensor data processing to perform resoning based on engine design and functional knowledge, as well as the principles of the relevant mechanics and physics.

Gupta, U. K.; Ali, M.

1989-01-01

160

Research Report Modeling seizure-related behavioral and endocrine  

E-print Network

Research Report Modeling seizure-related behavioral and endocrine phenotypes in adult zebrafish lower cortisol levels. Paralleling behavioral and endocrine phenotypes observed in clinical and rodent neurological disorder char- acterized by recurrent seizures, pathological brain hyperactivity and imbalances

Kalueff, Allan V.

161

Modeling Emotion Expression and Perception Behavior in Auditive Emotion Evaluation  

Microsoft Academic Search

In this paper, we consider both speaker dependent and listener dependent aspects in the assessment of emotions in speech. We model the speaker dependencies in emotional speech produc- tion by two parameters which describe the individual's emo- tional expression behavior. Similarly, we model the listener's emotion perception behavior by a simple parametric model. These models form a basis for improving

Michael Grimm; Kristian Kroschel; Shrikanth Narayanan

2006-01-01

162

Enhanced Core Noise Modeling for Turbofan Engines  

NASA Technical Reports Server (NTRS)

This report describes work performed by MTC Technologies (MTCT) for NASA Glenn Research Center (GRC) under Contract NAS3-00178, Task Order No. 15. MTCT previously developed a first-generation empirical model that correlates the core/combustion noise of four GE engines, the CF6, CF34, CFM56, and GE90 for General Electric (GE) under Contract No. 200-1X-14W53048, in support of GRC Contract NAS3-01135. MTCT has demonstrated in earlier noise modeling efforts that the improvement of predictive modeling is greatly enhanced by an iterative approach, so in support of NASA's Quiet Aircraft Technology Project, GRC sponsored this effort to improve the model. Since the noise data available for correlation are total engine noise spectra, it is total engine noise that must be predicted. Since the scope of this effort was not sufficient to explore fan and turbine noise, the most meaningful comparisons must be restricted to frequencies below the blade passage frequency. Below the blade passage frequency and at relatively high power settings jet noise is expected to be the dominant source, and comparisons are shown that demonstrate the accuracy of the jet noise model recently developed by MTCT for NASA under Contract NAS3-00178, Task Order No. 10. At lower power settings the core noise became most apparent, and these data corrected for the contribution of jet noise were then used to establish the characteristics of core noise. There is clearly more than one spectral range where core noise is evident, so the spectral approach developed by von Glahn and Krejsa in 1982 wherein four spectral regions overlap, was used in the GE effort. Further analysis indicates that the two higher frequency components, which are often somewhat masked by turbomachinery noise, can be treated as one component, and it is on that basis that the current model is formulated. The frequency scaling relationships are improved and are now based on combustor and core nozzle geometries. In conjunction with the Task Order No. 10 jet noise model, this core noise model is shown to provide statistical accuracy comparable to the jet noise model for frequencies below blade passage. This model is incorporated in the NASA FOOTPR code and a user s guide is provided.

Stone, James R.; Krejsa, Eugene A.; Clark, Bruce J.

2011-01-01

163

Hydrologic Behavior of Two Engineered Barriers Following Extreme Wetting  

SciTech Connect

Many engineered barriers are expected to function for hundreds of years or longer. Over the course of time, it is likely that some barriers will experience infiltration to the point of breakthrough. This study compares the recovery from breakthrough of two storage- evapotranspiration type engineered barriers. Replicates of test plots comprising thick soil and capillary/biobarrier covers were wetted to breakthrough in 1997. Test plots were kept cleared of vegetation to maximize hydrologic stress during recovery. Following cessation of drainage resulting from the wetting irrigations, water storage levels in all plots were at elevated levels compared to pre-irrigation levels. As a result, infiltration of melting snow during the subsequent spring overloaded the storage capacity and produced drainage in all plots. Relatively rapid melting of accumulated snowfall produced the most significant infiltration events each year during the study. Capillary barriers yielded less total drainage than thick soil barriers. By limiting drainage, capillary barriers increased water storage in the upper portions of the test plots, which led to increased evaporation from the capillary barrier plots compared to thick soil plots. Increased evaporation in the capillary barrier plots allowed more water to infiltrate in the second season following the wetting tests without triggering drainage. All thick soil plots again yielded drainage in the second season. Within two years of intentionally induced breakthrough, evaporation alone (without transpiration) restored the capability of the capillary barrier covers to function as intended, although water storage in these covers remained at elevated levels.

Porro, I.

2000-09-30

164

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

Microsoft Academic Search

Predictions of a free-piston Stirling engine model are compared with RE1000 Sunpower engine test data taken at NASA-Lewis Research Center. A kinematic code was upgraded to permit simulation of free-piston engine performance; it was further upgraded and modified and is currently being validated. The model predicts engine performance by numerical integration of equations for each control volume in the working

Tew

1984-01-01

165

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

ERIC Educational Resources Information Center

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

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

2010-01-01

166

A Simplified Dynamic Model of Space Shuttle Main Engine  

Microsoft Academic Search

This paper presents a simplified model 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 twenty five differenc operating points of the SSME. The simplified model was developed for use with a model-based diagnostic scheme for failure detection and diagnostics

Ahmet Duyar; Yasfi Eldem; Walter Merrill; Ten-Huei Guo

1991-01-01

167

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

168

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

169

Using Steam Engines to Teach Parametric Modeling and Prototyping  

Microsoft Academic Search

Using reprints from Root's original engine, students in the Engineering Technology Department at Western Carolina University embarked on creating parametric models, virtual assemblies, and animations in a senior level course. Further, rapid prototype models were produced to conduct fit analysis. Simultaneously, students in a machining and prototyping class developed a production system to fabricate the engines using CAM software and

Aaron K. Ball; Chip W. Ferguson; William L. McDaniel

170

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

171

Continuum Modelling of In Vitro Tissue Engineering: A Review  

E-print Network

Continuum Modelling of In Vitro Tissue Engineering: A Review RD O'Dea, HM Byrne and SL Waters Abstract By providing replacements for damaged tissues and organs, in vitro tissue engineering has. Mathematical modelling applied to tissue engineering repre- sents a powerful tool with which to investigate how

Waters, Sarah

172

A Simplified Analysis on a Pulse Detonation Engine Model  

Microsoft Academic Search

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

Takuma Endo; Toshi Fujiwara

2005-01-01

173

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

174

Investigation of bus transit schedule behavior modeling using advanced techniques  

SciTech Connect

This research focused on investigating the application of artificial neural networks (ANN) and the Box-Jenkins technique for developing and testing schedule behavior models using data obtained for a test route from Tidewater Regional Transit`s AVL system. The three ANN architectures investigated were: Feedforward Network, Elman Network and Jordan Network. In addition, five different model structures were investigated. The time-series methodology was adopted for developing the schedule behavior models. Finally, the role of a schedule behavior model within the framework of an intelligent transit management system is defined and the potential utility of the schedule behavior model is discussed using an example application.

Kalaputapu, R.; Demetsky, M.J.

1998-05-15

175

Loss terms in free-piston Stirling engine models  

NASA Technical Reports Server (NTRS)

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

Gordon, Lloyd B.

1992-01-01

176

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

177

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

178

Experimental study of rocket engine model with gaseous polyethylene fuel  

NASA Astrophysics Data System (ADS)

Experimental results for liquid rocket engine models with gaseous polyethylene fuel that is hard before its consumption are considered. The possibility of hard design element combustion in a liquid rocket engine is demonstrated.

Yemets, V. V.

179

A model of clocked micro-architectures for firmware engineering and design automation applications  

Microsoft Academic Search

An aspect common to many problems in firmware engineering is the use of a micromachine model that is, an abstract and selective view of the structure and behavior of the computer at the micro-architectural level. The success, utility and generality of a particular microprogramming language, compaction technique, or verification strategy may rest critically on the expressive power and generality of

Subrata Dasgupta

1984-01-01

180

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

181

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

182

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

183

Modeling Crowd Behavior Based on Social Comparison Theory: Extended Abstract  

E-print Network

Modeling Crowd Behavior Based on Social Comparison Theory: Extended Abstract Natalie Fridman model of crowd behavior, based on Festinger's Social Comparison Theory, a social psychology theory known. In computer science, models are often simplistic and typically not tied to specific cognitive science theories

Kaminka, Gal A.

184

Cognitive-Operative Model of Intelligent Learning Systems Behavior  

ERIC Educational Resources Information Center

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

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

2010-01-01

185

Elastic behavior of corrugated cardboard: experiments and modeling  

Microsoft Academic Search

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

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

2004-01-01

186

Behavior of human chondrocytes in engineered porous bacterial cellulose scaffolds.  

PubMed

Regeneration of articular cartilage damage is an area of great interest due to the limited ability of cartilage to self-repair. The latest cartilage repair strategies are dependent on access to biomaterials to which chondrocytes can attach and in which they can migrate and proliferate, producing their own extracellular matrix. In the present study, engineered porous bacterial cellulose (BC) scaffolds were prepared by fermentation of Acetobacter xylinum (A. xylinum) in the presence of slightly fused wax particles with a diameter of 150-300 microm, which were then removed by extrusion. This porous material was evaluated as a scaffold for cartilage regeneration. Articular chondrocytes from young adult patients as well as neonatal articular chondrocytes were seeded with various seeding techniques onto the porous BC scaffolds. Scanning electron microscopy (SEM) analysis and confocal microscopy analysis showed that cells entered the pores of the scaffolds and that they increasingly filled out the pores over time. Furthermore, DNA analysis implied that the chondrocytes proliferated within the porous BC. Alcian blue van Gieson staining revealed glycosaminoglycan (GAG) production by chondrocytes in areas where cells were clustered together. With some further development, this novel biomaterial can be a suitable candidate for cartilage regeneration applications. PMID:20694979

Andersson, Jessica; Stenhamre, Hanna; Bäckdahl, Henrik; Gatenholm, Paul

2010-09-15

187

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

188

SPECIAL ISSUE PAPER Modeling social behaviors in an evacuation simulator  

E-print Network

SPECIAL ISSUE PAPER Modeling social behaviors in an evacuation simulator Mei Ling Chu1 *, Paolo simulation; egress simulation; social agents; social behavior; simulated perception *Correspondence Mei Ling@stanford.edu 1. INTRODUCTION During evacuation, people often observe the behaviors of their social peers

Stanford University

189

Modeling Gaze Behavior as a Function of Discourse Structure  

E-print Network

-taking) and non-verbal behaviorsor the interaction between discourse structure and non-verbal behaviors. That is research that takes both types of linguistic structures into account in investigating non-verbal behaviorsModeling Gaze Behavior as a Function of Discourse Structure Obed E. Torres, Justine Cassell, Scott

Cassell, Justine

190

Modeling Gaze Behavior as a Function of Discourse Structure  

E-print Network

­taking) and non­verbal behaviorsor the interaction between discourse structure and non­verbal behaviors. That is research that takes both types of linguistic structures into account in investigating non­verbal behaviorsModeling Gaze Behavior as a Function of Discourse Structure Obed E. Torres, Justine Cassell, Scott

Cassell, Justine

191

Macro-and micro-behaviors in animal modeling of  

E-print Network

Macro- and micro-behaviors in animal modeling of neuropsychiatric disorders Allan V. Kalueff Peter entity These systems analyze the macro-behavioral levels in animals www.panlab.com #12;Current Challenges i l i l C l it Cost Physiological Complexity Modified from Kokel and Peterson, 2008 #12;Macro-behavioral

Kalueff, Allan V.

192

Mechanical behavior of titanium aluminide under engine operating conditions  

NASA Astrophysics Data System (ADS)

A brief study to optimize the heat treatment for a useful balance of mechanical properties in Ti-25 percent Al-10 percent Nb-3 percent V-1 percent Mo (atomic percent) was conducted. The selected heat treatment consisted of solution treatment at 1115 C (in the alpha + beta field, about 25 C below the transus temperature) in vacuum for 1 hour followed by cooling to room temperature in argon, followed by aging at 760 C in vacuum for 8 hours, followed by cooling at room temperature in argon. This treatment resulted in fine transformed microstructure with high (25 percent) volume fraction of primary alpha2-phase. This treatment resulted in superior fatigue crack growth resistance while still maintaining good tensile and creep properties. This solution and age heat treatment was used for study of the effects of several factors such as temperature (25, 425, 540, and 650 C), environment (air and ultrahigh vacuum), frequency (0.01 to 1 Hz), R-ratio (0.1 and 0.8), and orientation (parallel and perpendicular to the final rolling direction) on the fatigue crack growth behavior.

Jayaraman, N.

1992-08-01

193

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

194

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

E-print Network

, florianz@ethz.ch Semester Project IDSC-CO-RH-02 DPF Regeneration in the Gas-Diesel Engine Modeling 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

195

Model and control issues of gasoline engines  

Microsoft Academic Search

This mini-lecture focuses on the fundamentals of engine dynamics. Mainly, the basic technological knowledge for mathematically describing the dynamics of an internal combustion engines will be explained. Furthermore, some hot issues in the engine control fields will be introduced with several practical applications. Dynamics of automotive engines is a hybrid system that consists of continuous operations in the time and

Tielong Shen; Jiangyan Zhang

2011-01-01

196

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

197

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

198

Future Modeling Needs in Pulse Detonation Rocket Engine Design  

NASA Technical Reports Server (NTRS)

This paper presents a performance model rocket engine design that takes advantage of pulse detonation to generate thrust. The contents include: 1) Introduction to the Pulse Detonation Rocket Engine (PDRE); 2) PDRE modeling issues and options; 3) Discussion of the PDRE Performance Workshop held at Marshall Space Flight Center; and 4) Identify needs involving an open performance model for Pulse Detonation Rocket Engines. This paper is in viewgraph form.

Meade, Brian; Talley, Doug; Mueller, Donn; Tew, Dave; Guidos, Mike; Seymour, Dave

2001-01-01

199

Modelling Mixing Mechanisms Professor Ian Guymer, Professor of Civil Engineering  

E-print Network

Modelling Mixing Mechanisms Professor Ian Guymer, Professor of Civil Engineering School Conveyance networks are common in many aspects of civil engineering hydraulics, e.g. rivers, urban drainage THE SPEAKER Ian Guymer graduated from Loughborough University of Technology, in 1981 in Civil Engineering

Davies, Christopher

200

Developing an Efficient Model for Evaluating WWW Search Engines  

Microsoft Academic Search

The purpose of the work is to design an efficient methodology for evaluating the performance of public available WWW search engines. The first goal of this procedure is to develop a model representing WWW engines. This objective can only be accomplished by carefully studying the features of each search engine that is examined. This paper presents the methodology developed for

I. Despotopoulos; G. Korinthios; I. Nasios; D. Reisis

1999-01-01

201

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.

202

A Maturity Model for the Deployment of Systems Engineering Processes  

E-print Network

A Maturity Model for the Deployment of Systems Engineering Processes Clémentine Cornu Eurocopter. A solution is to apply the principles of Systems Engineering (SE), a proven interdisciplinary approach, presents its content and shows how to use it. Keywords - Systems Engineering processes deployment; Maturity

Paris-Sud XI, Université de

203

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

204

A simple model for Carnot heat engines Jacques Arnaud  

E-print Network

as a working agent two-level atoms. (For an exhaustive discussion concerning quantum heat engines see Quan.[4, , A simple model for Carnot heat engines Jacques Arnaud Mas Liron, F30440 Saint Martial, France is #17; = 1 E l =Eh . We then relate this system to a heat engine. This thermal interpretation

Recanati, Catherine

205

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

206

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

207

Model-based Security Engineering of Distributed Information Systems  

E-print Network

Jürjens, Bashar Nuseibeh BMW Group Munich, Germany Department of Computing The Open University, GB http://www.jurjens.de/jan #12;Best (BMW), J�RJENS, Nuseibeh (OU): Model-based Security Engineering... 2 Security is holistic #12;Best (BMW), J�RJENS, Nuseibeh (OU): Model-based Security Engineering... 3 (UML) Models

Jurjens, Jan

208

A behavioral model of ethical and unethical decision making  

Microsoft Academic Search

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

Michael Bommer; Clarence Gratto; Jerry Gravander; Mark Tuttle

1987-01-01

209

Large Time Behavior of Nonlocal Aggregation Models with Nonlinear Diffusion  

E-print Network

Large Time Behavior of Nonlocal Aggregation Models with Nonlinear Diffusion Martin Burger Marco Di behavior of non- local models for aggregation, including the possible presence of nonlinear diffusion terms and large time limits in the absence of diffusion. In addition, we provide a comparison for aggregation

Soatto, Stefano

210

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.

211

A SPICE BEHAVIORAL MODEL FOR CURRENT-CONTROLLED MAGNETIC INDUCTORS  

E-print Network

A SPICE BEHAVIORAL MODEL FOR CURRENT-CONTROLLED MAGNETIC INDUCTORS Evgeny Rozanov and Sam Ben@ee.bgu.ac.il Website: www.ee.bgu.ac.il/~pel ABSTRACT A new SPICE-compatible behavioral model for magnetic controlled the simulation and experimental results. 1. INTRODUCTION SPICE simulation of electronic circuits that include

212

Considerations for characterizing fuels as inputs for fire behavior models  

Microsoft Academic Search

Active crown fires affect forest ecosystem structure and function, and the livelihood of the surrounding human communities. Researchers and managers use simulation models to understand fire behavior and predict fire hazard. Accurate predictions depend on the capacity of simulation models to represent the processes that control fire behavior and on the quality of the data used. The data required to

Sonia A. Hall; Ingrid C. Burke

2006-01-01

213

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

Microsoft Academic Search

Predictions of a free-piston Stirling engine model are compared with RE1000 Sunpower 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 by Mechanical Technology, Inc. to

Tew

1984-01-01

214

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

215

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

216

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

Microsoft Academic Search

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

U. K. Gupta; Moonis Ali

1989-01-01

217

Nonlinear Behavior of Reinforced Concrete Shear Walls Using Macro Model  

NASA Astrophysics Data System (ADS)

A simple macro-model for reinforced concrete shear walls has been investigated. The proposed model consists of nonlinear spring elements representing flexural and shear behavior. The flexural behavior of the model is based on the uniaxial behavior of the vertical spring elements defined according to constitutive relations for materials and the tributary area assigned to each spring element which in turn leads to the integration of important material characteristics. The shear behavior is based on a trilinear force-displacement backbone curve assigned to each horizontal spring element. The model response has been predicted using nonlinear flexural and shear spring elements of the general purpose finite element program ABAQUS6.7. The analysis results show excellent agreement with experimental measurements of slender walls. The model turned out to be capable of simulating the nonlinear behavior of the selected test specimens at different stages of loading to a very good degree of accuracy within a few seconds of CPU time. The parametric studies conducted also show that the sensitivity of the model results to different modeling parameters is not significant. In order to evaluate the advantages and deficiencies of the investigated model in comparison with the models based on the finite element approach, the nonlinear behavior of the selected test specimens has been predicted using microscopic models. Although the microscopic model could simulate some important aspects of wall behavior such as the interaction between shear and flexural response components observed even in relatively slender RC walls, distribution of cracks and stresses and local behavior, the CPU time was considerably greater than the one needed for the analysis of the investigated macro-model, and the response of the model was relatively sensitive to mesh size. Taking the CPU time and simplicity into account, the observed agreement among three lateral load-displacement curves of experimental measurements, the macroscopic and microscopic models of test specimens indicates the efficiency of the investigated macro-model.

Jalali, A.; Dashti, F.

2008-07-01

218

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

219

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

220

Behavioral modeling of solute tracking in microfluidics  

Microsoft Academic Search

We present a general behavioral simulation method for the approximate solution of lumped, pressure-driven, static and time-dependent solute and solvent transport in large microfluidic chips. The method is based on a one-dimensional discretization of the convection-diffusion equation that tracks solvent and solute transport using four dual-branch nodal quantities. A comparison of static and transient behavior of microfluidic dilution networks and

Y. Zeng; F. Azizi; C. H. Mastrangelo

2009-01-01

221

Emerging Conceptual Models of Excessive Behaviors  

Microsoft Academic Search

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

James Westphal

2007-01-01

222

Calibrating Bayesian Network Representations of Social-Behavioral Models  

SciTech Connect

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

Whitney, Paul D.; Walsh, Stephen J.

2010-04-08

223

Modeling of hybrid vehicle fuel economy and fuel engine efficiency  

NASA Astrophysics Data System (ADS)

"Near-CV" (i.e., near-conventional vehicle) hybrid vehicles, with an internal combustion engine, and a supplementary storage with low-weight, low-energy but high-power capacity, are analyzed. This design avoids the shortcoming of the "near-EV" and the "dual-mode" hybrid vehicles that need a large energy storage system (in terms of energy capacity and weight). The small storage is used to optimize engine energy management and can provide power when needed. The energy advantage of the "near-CV" design is to reduce reliance on the engine at low power, to enable regenerative braking, and to provide good performance with a small engine. The fuel consumption of internal combustion engines, which might be applied to hybrid vehicles, is analyzed by building simple analytical models that reflect the engines' energy loss characteristics. Both diesel and gasoline engines are modeled. The simple analytical models describe engine fuel consumption at any speed and load point by describing the engine's indicated efficiency and friction. The engine's indicated efficiency and heat loss are described in terms of several easy-to-obtain engine parameters, e.g., compression ratio, displacement, bore and stroke. Engine friction is described in terms of parameters obtained by fitting available fuel measurements on several diesel and spark-ignition engines. The engine models developed are shown to conform closely to experimental fuel consumption and motored friction data. A model of the energy use of "near-CV" hybrid vehicles with different storage mechanism is created, based on simple algebraic description of the components. With powertrain downsizing and hybridization, a "near-CV" hybrid vehicle can obtain a factor of approximately two in overall fuel efficiency (mpg) improvement, without considering reductions in the vehicle load.

Wu, Wei

224

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

225

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

226

Model-based reasoning: a principled approach for software engineering  

Microsoft Academic Search

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

M. H. Lee

2000-01-01

227

Requirements Engineering meets Trust Model, Methodology, and Reasoning  

E-print Network

, capturing trust and security requirements at an orga- nizational level (as opposed to a design level methodology. The key intuition is that in modeling security and trust, we need to distinguish between Engineering for Security and Trust, Agent- Oriented Technologies, Security Engineering, Trust Models

Massacci, Fabio

228

Model for the Performance of Airbreathing Pulse-Detonation Engines  

Microsoft Academic Search

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

E. Wintenberger; J. E. Shepherd

2006-01-01

229

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

SciTech Connect

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

230

First International Workshop on Social Computing, Behavioral Modeling, and Prediction Phoenix (Sedona), Arizona  

E-print Network

First International Workshop on Social Computing, Behavioral Modeling, and Prediction Phoenix by Springer Social computing is concerned with the study of social behavior and social context based on computational systems. Behavioral modeling reproduces the social behavior, and allows for experimenting

Liu, Huan

231

Second International Workshop on Social Computing, Behavioral Modeling, and Prediction Phoenix, Arizona  

E-print Network

Second International Workshop on Social Computing, Behavioral Modeling, and Prediction Phoenix is concerned with the study of social behavior and social context based on computational systems. Behavioral modeling reproduces the social behavior, and allows for experimenting, scenario planning, and deep

Liu, Huan

232

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

233

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

234

Modeling for the Dynamics of Human Innovative Behaviors  

E-print Network

How to promote the innovative activities is an important problem for modern society. In this paper, combining with the evolutionary games and information spreading, we propose a lattice model to investigate dynamics of human innovative behaviors based on benefit-driven assumption. Simulations show several properties in agreement with peoples' daily cognition on innovative behaviors, such as slow diffusion of innovative behaviors, gathering of innovative strategy on "innovative centers", and quasi-localized dynamics. Furthermore, our model also emerges rich non-Poisson properties in the temporal-spacial patterns of the innovative status, including the scaling law in the interval time of innovation releases and the bimodal distributions on the spreading range of innovations, which would be universal in human innovative behaviors. Our model provide a basic framework on the study of the issue relevant to the evolution of human innovative behaviors and the promotion measurement of innovative activities.

Lin, Ying-Ting; Wang, Bing-Hong

2013-01-01

235

Analysis of radical behavior under knocking operation in a spark ignition engine  

SciTech Connect

There are strong demands today to improve the thermal efficiency of internal combustion engines in order to promote energy conservation and the resolution of environmental issues. A major factor impeding further improvement of the thermal efficiency of spark-ignition engines is knocking. If knocking could be suppressed, it would allow the use of a higher compression ratio for improved thermal efficiency, and thereby reduce fuel consumption. As a result, atmospheric emissions of CO{sub 2} would also be reduced. The behavior of the end gas in an actual engine during the process from the onset of preflame reactions to the occurrence of knocking, including the chemical reactions involved, is still not clearly understood. This study focused on light emission behavior at wavelengths corresponding to the spectra of the formaldehyde, (HCHO, characteristic spectrum of 395.2 nm), HCO (329.8 nm) and OH (306.4 nm) radicals. Investigations were made of the role of low-temperature flames in the preflame reaction region of a spark-ignition engine under the occurrence of autoignition leading to knocking. The measurements obtained for HCHO when the blended fuel (20 RON) was used as the test fuel showed an increase in emission intensity in the early period of the preflame reactions under normal combustion, followed by a decline in intensity. Under a condition of severe knock induced by an overheated cylinder head, it was observed that the maximum emission intensity decreased. These tendencies are thought to correspond to the passage and degeneracy of a cool flame. When isooctane (100 RON) was used as the test fuel, the measurements obtained for HCHO showed an increase in emission intensity in the preflame reaction period, behavior thought to indicate the passage of a cool flame, but the characteristics associated with the degeneracy of a cool flame were not observed.

Ota, Yasushi; Komuro, Katsunori; Matsushima, Toshiyuki; Yoshida, Koji; Shoji, Hideo; Saima, Atsushi

1999-07-01

236

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

237

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

238

Towards a Model of Collaborative Information Behavior  

Microsoft Academic Search

The research area of Collaborative Information Behavior (CIB) has received increased interest in recent years. Various studies conducted within organizational as well as non-organizational settings have provided us with many key insights about CIB. However, the research area is still relatively young and is at a pre- paradigmatic stage. Although there are a growing number of CIB-related studies, we still

Arvind Karunakaran; Patricia Ruma Spence; Madhu C. Reddy

239

Kinetic Monte Carlo Model Simulations of Nanoscale Oxidation Behavior  

Microsoft Academic Search

Nucleation rate theory has been successfully used to describe metal heteroepitaxy and qualitatively explained the initial stage of oxidation behavior. To further quantitative understanding of these nano-scale processes and morphological evolution, the Thin Film Oxidation (TFOx) program based on Kinetic Monte Carlo (KMC) has been developed. The TFOx model can be used to simulate the general behavior of irreversible nucleation

Judith Yang; Xuetian Han; Richard McAfee

2005-01-01

240

Biosocial models of deviant behavior among male army veterans  

Microsoft Academic Search

Measures of hormones (testosterone, cortisol and thyroxin) and of deviant or antisocial behavior are examined in a sample of 4179 Vietnam veterans. Hormone levels were found to vary with veterans age, social status and race, and all three hormones were significantly related to deviant behavior. Biosocial models, combining hormonal variables with social background variables, tended to explain more variance in

Allan Mazur

1995-01-01

241

A Test of a Model of Achievement Behaviors  

Microsoft Academic Search

Drawing on the theoretical and empirical work of decision making, achievement, and attribution theorists, Eccles and colleagues (1983) proposed an integrative theoretical model of achievement behaviors (e.g., persistence, choice, and performance). Defining achievement behavior as the intention to study more mathematics, the present study sought to determine the extent to which the key constructs within the psychological component of the

Corinna A. Ethington

1991-01-01

242

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

243

A variable-response model for parasitoid foraging behavior  

Microsoft Academic Search

An important factor inducing variability in foraging behavior in parasitic wasps is experience gained by the insect. Together with the insect's genetic constitution and physiological state, experience ultimately defines the behavioral repertoire under specified environmental circumstances. We present a conceptual variable-response model based on several major observations of a foraging parasitoid's responses to stimuli involved in the hostfinding process. These

L. E. M. Vet; W. J. Lewis; D. R. Papaj; J. C. van Lenteren

1990-01-01

244

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

245

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

246

A Meta-Analytic Review of Behavior Modeling Training  

ERIC Educational Resources Information Center

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

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

2005-01-01

247

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

248

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

249

A new modeling approach of pressure waves at the inlet of internal combustion engines  

NASA Astrophysics Data System (ADS)

This paper presents a new model used to describe the propagation of pressure waves at the inlet systems of internal combustion engine. In the first part, an analogy is made between the compressible air in a pipe and a mechanical ideal mass damper spring system. A new model is then presented and the parameters of this model are determined by the use of an experimental setup (shock tube test bench). With this model, a transfer function is defined in order to link directly the pressure and the air mass flow rate. In the second part, the model is included into an internal combustion engine simulation code. The results obtained with this code are compared to experimental ones which are measured on a one-cylinder engine test bench. This last one is driven by an electric motor in order to study only the effect of the pressure waves on the engine behavior. A good agreement is obtained between the experimental results and the numerical ones and the new approach is an alternative method for modeling the pressure wave phenomena in an internal combustion engine manifold.

Chalet, David; Mahé, Alexandre; Hétet, Jean-François; Migaud, Jérôme

2011-06-01

250

A catastrophe-theory model for simulating behavioral accidents  

SciTech Connect

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

Souder, W.E.

1988-01-01

251

A Robot Model of Function Behavior in C/C++.  

ERIC Educational Resources Information Center

Discussion of students' difficulties in C and C++ courses focuses on the function concept. Discusses function behavior through a model that uses a robot and its specially constructed environment, and distinguishes between the terms argument and parameter. (Author/LRW)

Molluzzo, John C.

2002-01-01

252

Behavioral Model for Assessing Cognitive Decline  

PubMed Central

The water maze task can be used to assess sensory motor and cognitive function in rodents. When properly employed, this task can behaviorally assess acquisition of a spatial search strategy, as well as working and reference memory. The following section uses research on age-related, cognitive decline to illustrate the methods employed and highlight areas that can, if not properly controlled, confound a study. PMID:22231811

Guidi, Michael; Foster, Thomas C.

2013-01-01

253

The benefits of model building in teaching engineering design  

E-print Network

, 108 Bromfield Road, Somerville, MA 02144, USA Using verbal protocol analysis, we report how model students uncover differences between real behavior and the conceptual model used to predict that behavior, draw- ings, verbal accounts, and written communications, there is less in the litera- ture

254

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

255

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

256

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

257

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

258

Asymptotic Behavior of Solutions of the Hydrodynamic Model of Semiconductors  

E-print Network

Asymptotic Behavior of Solutions of the Hydrodynamic Model of Semiconductors Hailiang Li , Peter of steady-state solution in subsonic case for the one-dimensional hydrodynamic model of semiconductors for semiconductors has recently attracted a lot of attention because of its ability to model hot electron effects

Markowich, Peter A.

259

Asymptotic Behavior of Solutions of the Hydrodynamic Model of Semiconductors  

E-print Network

Asymptotic Behavior of Solutions of the Hydrodynamic Model of Semiconductors Hailiang Li # , Peter of semiconductors. In the present paper, we reconsider the existence and uniqueness of globally smooth subsonic], the hydrodynamic model for semiconductors has recently attracted a lot of attention because of its ability to model

Markowich, Peter A.

260

A cognitive-behavioral model of compulsive hoarding  

Microsoft Academic Search

Compulsive hoarding is a little studied phenomenon within the research literature. The information available on compulsive hoarding is diverse and not well integrated. In the present article we propose a tentative cognitive-behavioral model of compulsive hoarding. The purpose of such a model is to provide a framework for the development and testing of hypotheses about compulsive hoarding. In this model

Randy O. Frost; Tamara L. Hartl

1996-01-01

261

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

262

Engineering design of gas-condensate pipelines with a compositional hydrodynamic model  

SciTech Connect

Gas condensation in pipelines designed to transport natural gas is common. The difference in the engineering design required for this system, compared with the required of dry gas pipelines, makes the problem of significant interest to the gas industry. Because the point and quantity of condensation is not usually known a priori, any attempt to develop a predictive capability for such a system must have an inherent means of providing this information. This requires a good coupling of the gas-phase behavior model with the appropriate hydrodynamic model. This paper reports work to develop such a model. With a two-parameter equation of state (EOS) to describe the phase behavior of the natural-gas system, a multiphase hydrodynamic model developed from fundamental fluid dynamics is used to describe the hydrodynamic behavior of the resulting two phases. The model, which consists of a system of nonlinear algebraic and ordinary differential equations (ODE's), was solved numerically. Output from the model solution includes quantity of condensation at any point in the pipeline, pressure drop, and other hydrodynamic variables. The model can predict the various engineering parameters of interest in the design of such pipelines and could be used for feasibility studies and for optimal location of fluid-handling equipment.

Vincent, P.A. (Trinidad Ministry of Energy (TT)); Adewumi, M.A. (Pennsylvania State Univ., University Park, PA (USA). Dept. of Petroleum and Natural Gas)

1990-11-01

263

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

264

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

Federal Register 2010, 2011, 2012, 2013

...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

265

A Framework for Engineering the Collective Behavior of Complex Rhythmic Systems  

PubMed Central

We have developed an engineering framework which utilizes experiment-based phase models to tune complex dynamic structures to desired states; weak, non-destructive signals are employed to alter interactions among nonlinear rhythmic elements. In this manuscript we present an integrated overview and discussion of our recent studies in this area. Experiments on electrochemical reactions were conducted using multi-electrode arrays to demonstrate the use of mild model-engineered feedback to achieve a desirable system response. Application is made to the tuning of phase difference between two oscillators, generation of sequentially-visited dynamic cluster patterns, engineering dynamically differentiated cluster states, and to the design of a nonlinear anti-pacemaker for the destruction of synchronization of a population of interacting oscillators. PMID:20174453

Rusin, Craig G.; Kiss, István Z.; Kori, Hiroshi; Hudson, John L.

2010-01-01

266

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

267

Augmented Network Model For Engineering System Design  

E-print Network

research (supply chains), electrical engineering (circuit (controls) theory), and more recently systems the components of a vehicle, the parts (or subsystems) of an airplane or the states of a formation of flying

de Weck, Olivier L.

268

Modeling techniques for simulating well behavior  

E-print Network

commingled layers . 72 8-2 The simulated pressure drawdown behavior agrees with that of Tariq and Ramey' . 75 8-3 8-4 Depletion performance of two commingled layers shows production from the more permeable layer dominate the total production during... curve was indistinguishable from that 1'or a single-layer system as long as the skin factor was the same in both layers. Tariq and Ramey" presented solutions for a constant rate, bounded, multilayer system that include the skin effect in each layer...

Rattu, Bungen Christina

2002-01-01

269

Marine Diesel Engine Process Modelling and Control Using Advanced Technologies  

Microsoft Academic Search

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

R. Antonic; Z. Vukic; O. Kuljaca

2005-01-01

270

Building a search engine model with morphological normalization support  

Microsoft Academic Search

Searching a collection of documents can seem like an easy task, but manipulating textual data can be difficult because the data are mostly unstructured. We undertook the task of building an effective search engine for a collection of Croatian legislative documents. The developed search engine model supports multiple modules for information retrieval. To improve the effectiveness of the retrieval, we

Jure Mijic; J. Snajder

2008-01-01

271

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

272

Modeling Student Interest in Science, Technology, Engineering and Mathematics  

Microsoft Academic Search

This paper presents preliminary results of a Raytheon project that uses systems engineering techniques to understand the intricacies of the U.S. educational system and to assist in the evaluation of proposed system changes with a goal of doubling the numbers of science, technology, engineering and mathematics (STEM) college graduates by 2015. Specifically, a system dynamics model has been developed, the

Brian H. Wells; H. Alex Sanchez; Joanne M. Attridge

2007-01-01

273

CIS 786: Simulation and Modeling for Engineering and Business  

E-print Network

CIS 786: Simulation and Modeling for Engineering and Business To be offered: Fall 2004 at NJIT use in engineering and business has increased dramatically in recent years, in part because in a business environment include evaluating alternative operational policies, viewing the impact of changes

Lin, Xiaodong

274

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

275

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

276

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

277

User Interface Plasticity: Model Driven Engineering to the Limit!  

E-print Network

service composition, does not cover any of the HCI-centered concerns. Research in autonomic systems, user interface composition, dynamic service composition, model driven engineering (MDE), service-oriented architecture (SOA). ACM Classification Keywords D.2.2 [Software Engineering]: Design Tools and Techniques

278

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

279

Modeling synchronized calling behavior of Japanese tree frogs  

NASA Astrophysics Data System (ADS)

We experimentally observed synchronized calling behavior of male Japanese tree frogs Hyla japonica; namely, while isolated single frogs called nearly periodically, a pair of interacting frogs called synchronously almost in antiphase or inphase. In this study, we propose two types of phase-oscillator models on different degrees of approximations, which can quantitatively explain the phase and frequency properties in the experiment. Moreover, it should be noted that, although the second model is obtained by fitting to the experimental data of the two synchronized states, the model can also explain the transitory dynamics in the interactive calling behavior, namely, the shift from a transient inphase state to a stable antiphase state. We also discuss the biological relevance of the estimated parameter values to calling behavior of Japanese tree frogs and the possible biological meanings of the synchronized calling behavior.

Aihara, Ikkyu

2009-07-01

280

Modeling engine oil vaporization and transport of the oil vapor in the piston ring pack on internal combustion engines  

E-print Network

A model was developed to study engine oil vaporization and oil vapor transport in the piston ring pack of internal combustion engines. With the assumption that the multi-grade oil can be modeled as a compound of several ...

Cho, Yeunwoo, 1973-

2004-01-01

281

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

282

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

283

Video Self-Modeling and Cooperative Classroom Behavior in Children with Learning and Behavior Problems: Training and Generalization Effects.  

ERIC Educational Resources Information Center

This study of two primary-grade students with learning disabilities and behavior problems found that an instructional package incorporating videotaped self-assessment, self-modeling, discrimination training, and behavioral rehearsal helped the children acquire cooperative classroom behaviors and generalize and maintain those behaviors. (Author/JDD)

Lonnecker, Cecilia; And Others

1994-01-01

284

Engine System Model Development for Nuclear Thermal Propulsion  

NASA Technical Reports Server (NTRS)

In order to design, analyze, and evaluate conceptual Nuclear Thermal Propulsion (NTP) engine systems, an improved NTP design and analysis tool has been developed. The NTP tool utilizes the Rocket Engine Transient Simulation (ROCETS) system tool and many of the routines from the Enabler reactor model found in Nuclear Engine System Simulation (NESS). Improved non-nuclear component models and an external shield model were added to the tool. With the addition of a nearly complete system reliability model, the tool will provide performance, sizing, and reliability data for NERVA-Derived NTP engine systems. A new detailed reactor model is also being developed and will replace Enabler. The new model will allow more flexibility in reactor geometry and include detailed thermal hydraulics and neutronics models. A description of the reactor, component, and reliability models is provided. Another key feature of the modeling process is the use of comprehensive spreadsheets for each engine case. The spreadsheets include individual worksheets for each subsystem with data, plots, and scaled figures, making the output very useful to each engineering discipline. Sample performance and sizing results with the Enabler reactor model are provided including sensitivities. Before selecting an engine design, all figures of merit must be considered including the overall impacts on the vehicle and mission. Evaluations based on key figures of merit of these results and results with the new reactor model will be performed. The impacts of clustering and external shielding will also be addressed. Over time, the reactor model will be upgraded to design and analyze other NTP concepts with CERMET and carbide fuel cores.

Nelson, Karl W.; Simpson, Steven P.

2006-01-01

285

Modulating and modeling aggregation of cell-seeded microcarriers in stirred culture system for macrotissue engineering.  

PubMed

A recently developed protocol, "microtissue assembly" holds great promise to address the issue of limited mass transfer within engineered large tissue replacements (macrotissues), wherein small "building blocks" (microtissues) are prepared and then assembled into macrotissues. Previous studies suggested that aggregation behavior of microcarrier-based microtissues were very important for macrotissue engineering. However, a systematic study on the aggregation behavior of microtissues is still missing. In this study, to examine the aggregation behavior of microtissues, effects of key operation parameters in dynamic culture including cell seeding density, microcarrier concentration, L-ascorbic acid 2-phosphate (V(c)) and agitating speed were investigated. The aggregation process could be divided into three phases (i.e., lag, growth and stable). Aggregation efficiency (S) was found to be modulated by cell seeding density, microcarrier concentration, addition of V(c) and agitating speed. A mathematical model correlating the operation parameters with S at different phases of aggregation was developed and experimentally proved to be able to predict S with varied operation parameters. In the end, a cylindrical macrotissue (diameter × height: 2.0 cm × 0.8 cm) with fairly good integrity and cellularity and uniform cell distribution was successfully engineered through perfusion assembling microtissues with controlled S under selected culture conditions. Our study showed that aggregation of microtissues could be precisely modulated, which would definitely facilitate engineering macrotissues with high quality. PMID:20888876

Mei, Yang; Luo, Houyong; Tang, Qiang; Ye, Zhaoyang; Zhou, Yan; Tan, Wen-Song

2010-11-01

286

Modeling User Behavior in Computer Learning Tasks.  

ERIC Educational Resources Information Center

Model building techniques from Artifical Intelligence and Information-Processing Psychology are applied to human-computer interface tasks to evaluate existing interfaces and suggest new and better ones. The model is in the form of an augmented transition network (ATN) grammar which is built by applying grammar induction heuristics on a sequential…

Mantei, Marilyn M.

287

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

288

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

SciTech Connect

Predictions of a free-piston Stirling engine model are compared with RE1000 Sunpower 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 by Mechanical Technology, Inc. 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.

1984-08-01

289

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

290

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.

291

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

292

A three-level non-deterministic modeling methodology for the NVH behavior of rubber connections  

NASA Astrophysics Data System (ADS)

Complex built-up structures such as vehicles have a variety of joint types, such as spot-welds, bolted joints, rubber joints, etc. Rubber joints highly contribute to the nonlinear level of the structure and are a major source of uncertainties and variability. In the general framework of developing engineering tools for virtual prototyping and product refinement, the modeling of the NVH behavior of rubber joints involve the computational burden of including a detailed nonlinear model of the joint and the uncertainties and variability typical of that joint in a full-scale system model. However, in an engineering design phase the knowledge on the joint rubber material properties is typically poor, and the working conditions a rubber joint will experience are generally not known in detail. This lack of knowledge often do not justify the computational burden and the modeling effort of including detailed nonlinear models of the joint in a full-scale system model. Driven by these issues a non-deterministic numerical methodology based on a three-level modeling approach is being developed. The methodology aims at evaluating directly in the frequency domain the sensitivity of the NVH behavior of a full-scale system model to the rubber joint material properties when nonlinear visco-elastic rubber material behavior is considered. Rather than including directly in the model a representation of the rubber nonlinear visco-elastic behavior, the methodology proposes to model the material nonlinear visco-elastic behavior by using a linear visco-elastic material model defined in an interval sense, from which the scatter on the full-scale system NVH response is evaluated. Furthermore the development of a multi-level solution scheme allows to reduce the computational burden introduced by the non-deterministic approach by allowing the definition of an equivalent linear interval parametric rubber joint model, ready to be assembled in a full-scale system model at a reasonable computational cost. By using a commercial finite element code the developed methodology is illustrated through a numerical case-study: the low-frequency dynamic analysis of automotive door weather-strip seals.

Stenti, A.; Moens, D.; Sas, P.; Desmet, W.

2010-03-01

293

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

294

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

295

Engineering change modelling using a function-behaviour-structure scheme  

E-print Network

for insightful discussions, and Agusta- Westland Helicopters Ltd., Perkins Engines Company Ltd., and the collaborating international SEM manufacturer that wished to remain unnamed in this thesis to preserve confidentiality for the extensive information... Design Centre FR Functional reasoning FBS Function, behaviour, and structure FBSta Function-Behaviour-State model FBStr Function-Behaviour-Structure model ICED Conference on Engineering Design MDM Multi domain matrix PD Product development...

Hamraz, Bahram

2013-11-12

296

Complex Systems for Human Body Biomechanical Behavior Modeling  

NASA Astrophysics Data System (ADS)

In this paper, we will explore the way we are able to obtain some information about human body behavior during gait or stability actions using video and tracking capture and transpose these data on a virtual model for the simulation process. In the first part of the paper we presented some considerations about the problems developed by human body modeling and its interactions with the environment. In the final part we presented some recordings of the human body movements during the gait process and the model built to analyze biomechanical behavior of the human body.

Baritz, Mihaela; Cristea, Luciana; Rogozea, Liliana; Cotoros, Diana; Ion, Balcu

2009-04-01

297

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.

Zhou, Zhuping; Hu, Qizhou; Wang, Wei

2014-01-01

298

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

299

A Bayesian framework for simultaneously modeling neural and behavioral data?  

PubMed Central

Scientists who study cognition infer underlying processes either by observing behavior (e.g., response times, percentage correct) or by observing neural activity (e.g., the BOLD response). These two types of observations have traditionally supported two separate lines of study. The first is led by cognitive modelers, who rely on behavior alone to support their computational theories. The second is led by cognitive neuroimagers, who rely on statistical models to link patterns of neural activity to experimental manipulations, often without any attempt to make a direct connection to an explicit computational theory. Here we present a flexible Bayesian framework for combining neural and cognitive models. Joining neuroimaging and computational modeling in a single hierarchical framework allows the neural data to influence the parameters of the cognitive model and allows behavioral data, even in the absence of neural data, to constrain the neural model. Critically, our Bayesian approach can reveal interactions between behavioral and neural parameters, and hence between neural activity and cognitive mechanisms. We demonstrate the utility of our approach with applications to simulated fMRI data with a recognition model and to diffusion-weighted imaging data with a response time model of perceptual choice. PMID:23370060

Turner, Brandon M.; Forstmann, Birte U.; Wagenmakers, Eric-Jan; Brown, Scott D.; Sederberg, Per B.; Steyvers, Mark

2013-01-01

300

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

301

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

302

Modeling Developmental Complexity in Adolescence: Hormones and Behavior in Context.  

ERIC Educational Resources Information Center

The links between endocrine physiological processes and adolescent psychological processes are the focus of this article. Presents a brief history of biopsychosocial research in adolescent development. Discusses four models for conceptualizing hormone-behavior research as illustrative of biopsychosocial models. Concludes with challenges and…

Susman, Elizabeth J.

1997-01-01

303

Shuttle passenger couch. [design and performance of engineering model  

NASA Technical Reports Server (NTRS)

Conceptual design and fabrication of a full scale shuttle passenger couch engineering model are reported. The model was utilized to verify anthropometric dimensions, reach dimensions, ingress/egress, couch operation, storage space, restraint locations, and crew acceptability. These data were then incorported in the design of the passenger couch verification model that underwent performance tests.

Rosener, A. A.; Stephenson, M. L.

1974-01-01

304

The Marshall Engineering Thermosphere (MET) Model. Volume 1; Technical Description  

NASA Technical Reports Server (NTRS)

Volume 1 presents a technical description of the Marshall Engineering Thermosphere (MET) model atmosphere and a summary of its historical development. Various programs developed to augment the original capability of the model are discussed in detail. The report also describes each of the individual subroutines developed to enhance the model. Computer codes for these subroutines are contained in four appendices.

Smith, R. E.

1998-01-01

305

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

306

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

307

Behavioral phenotyping of mouse models of Parkinson's Disease  

PubMed Central

Parkinson's disease (PD) is a common neurodegenerative movement disorder afflicting millions of people in the United States. The advent of transgenic technologies has contributed to the development of several new mouse models, many of which recapitulate some aspects of the disease; however, no model has been demonstrated to faithfully reproduce the full constellation of symptoms seen in human PD. This may be due in part to the narrow focus on the dopamine-mediated motor deficits. As current research continues to unmask PD as a multi-system disorder, animal models should similarly evolve to include the non-motor features of the disease. This requires that typically cited behavioral test batteries be expanded. The major non-motor symptoms observed in PD patients include hyposmia, sleep disturbances, gastrointestinal dysfunction, autonomic dysfunction, anxiety, depression, and cognitive decline. Mouse behavioral tests exist for all of these symptoms and while some models have begun to be reassessed for the prevalence of this broader behavioral phenotype, the majority has not. Moreover, all behavioral paradigms should be tested for their responsiveness to L-DOPA so these data can be compared to patient response and help elucidate which symptoms are likely not dopamine-mediated. Here, we suggest an extensive, yet feasible, battery of behavioral tests for mouse models of PD aimed to better assess both non-motor and motor deficits associated with the disease. PMID:20211655

Taylor, Tonya N.; Greene, James G.; Miller, Gary W.

2010-01-01

308

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

309

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

310

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

311

Modeling organizations for information systems requirements engineering  

Microsoft Academic Search

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

Eric S. K. Yu

1993-01-01

312

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

313

Trigonometric models for scaling behavior near criticality  

Microsoft Academic Search

Parametric scaling representations of the asymptotic equation of state, correlation lengths, and singular part of the Helmholtz free energy in the critical region of a system with a scalar order parameter are considered with the aim of fitting all 15 available independent universal amplitude ratios and describing naturally van der Waals loops. Defects in previous linear and cubic models and

Michael E. Fisher; Shun-Yong Zinn; Paul J. Upton

1999-01-01

314

Modeling pedestrian shopping behavior using principles of bounded rationality: model comparison and validation  

NASA Astrophysics Data System (ADS)

Models of geographical choice behavior have been dominantly based on rational choice models, which assume that decision makers are utility-maximizers. Rational choice models may be less appropriate as behavioral models when modeling decisions in complex environments in which decision makers may simplify the decision problem using heuristics. Pedestrian behavior in shopping streets is an example. We therefore propose a modeling framework for pedestrian shopping behavior incorporating principles of bounded rationality. We extend three classical heuristic rules (conjunctive, disjunctive and lexicographic rule) by introducing threshold heterogeneity. The proposed models are implemented using data on pedestrian behavior in Wang Fujing Street, the city center of Beijing, China. The models are estimated and compared with multinomial logit models and mixed logit models. Results show that the heuristic models are the best for all the decisions that are modeled. Validation tests are carried out through multi-agent simulation by comparing simulated spatio-temporal agent behavior with the observed pedestrian behavior. The predictions of heuristic models are slightly better than those of the multinomial logit models.

Zhu, Wei; Timmermans, Harry

2011-06-01

315

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

316

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

317

Modeling Structural, Dyadic, and Individual Factors: The Inclusion and Exclusion Model of HIV Related Behavior  

PubMed Central

Changing HIV-related behaviors requires addressing the individual, dyadic, and structural influences that shape them. This supplement of AIDS & Behavior presents frameworks that integrate these three influences on behavior. Concepts from these frameworks were selected to model the processes by which structural factors affect individual HIV-related behavior. In the Inclusion/Exclusion Model, material and symbolic inclusions and exclusions (sharing versus denying resources) regulate individuals’ ability and motivation to detect, prevent, and treat HIV. Structural interventions create inclusions that increase one’s ability or motivation to perform these behaviors or exclusions that hinder one’s ability or motivation to execute counterproductive behaviors. The need to expand research regarding multilevel influences on HIV-related behavior is also discussed, particularly concerning further understanding of sustained behavior change and effective dissemination of evidence-based intervention strategies. PMID:20848306

Tannenbaum, Melanie B.; Glasman, Laura R.; Rothman, Alexander J.

2013-01-01

318

EFFECTS OF VIDEO MODELING ON TREATMENT INTEGRITY OF BEHAVIORAL INTERVENTIONS  

PubMed Central

We examined the effects of individualized video modeling on the accurate implementation of behavioral interventions using a multiple baseline design across 3 teachers. During video modeling, treatment integrity improved above baseline levels; however, teacher performance remained variable. The addition of verbal performance feedback increased treatment integrity to 100% for all participants, and performance was maintained 1 week later. Teachers found video modeling to be more socially acceptable with performance feedback than alone, but rated both positively. PMID:21119903

DiGennaro-Reed, Florence D; Codding, Robin; Catania, Cynthia N; Maguire, Helena

2010-01-01

319

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

320

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

321

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

322

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

323

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

324

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

325

Alterations in choice behavior by manipulations of world model  

PubMed Central

How to compute initially unknown reward values makes up one of the key problems in reinforcement learning theory, with two basic approaches being used. Model-free algorithms rely on the accumulation of substantial amounts of experience to compute the value of actions, whereas in model-based learning, the agent seeks to learn the generative process for outcomes from which the value of actions can be predicted. Here we show that (i) “probability matching”—a consistent example of suboptimal choice behavior seen in humans—occurs in an optimal Bayesian model-based learner using a max decision rule that is initialized with ecologically plausible, but incorrect beliefs about the generative process for outcomes and (ii) human behavior can be strongly and predictably altered by the presence of cues suggestive of various generative processes, despite statistically identical outcome generation. These results suggest human decision making is rational and model based and not consistent with model-free learning. PMID:20805507

Green, C. S.; Benson, C.; Kersten, D.; Schrater, P.

2010-01-01

326

3D Engineered Models for Highway Construction Gabe Nelson, P.E.  

E-print Network

3D Engineered Models for Highway Construction Gabe Nelson, P.E. Snyder & Associates, Inc. Overview of 3D Engineered Models for Highway Construction Module 1 Introduction #12;3D Engineered Models & Quality ­ Protect the Environment · Every Day Counts 2 included 3D Engineered Models for Construction

327

Lattice Model for Influenza Spreading with Spontaneous Behavioral Changes  

PubMed Central

Individual behavioral response to the spreading of an epidemic plays a crucial role in the progression of the epidemic itself. The risk perception induces individuals to adopt a protective behavior, as for instance reducing their social contacts, adopting more restrictive hygienic measures or undergoing prophylaxis procedures. In this paper, starting with a previously developed lattice-gas SIR model, we construct a coupled behavior-disease model for influenza spreading with spontaneous behavioral changes. The focus is on self-initiated behavioral changes that alter the susceptibility to the disease, without altering the contact patterns among individuals. Three different mechanisms of awareness spreading are analyzed: the local spreading due to the presence in the neighborhood of infective individuals; the global spreading due to the news published by the mass media and to educational campaigns implemented at institutional level; the local spreading occurring through the “thought contagion” among aware and unaware individuals. The peculiarity of the present approach is that the awareness spreading model is calibrated on available data on awareness and concern of the population about the risk of contagion. In particular, the model is validated against the A(H1N1) epidemic outbreak in Italy during the season, by making use of the awareness data gathered by the behavioral risk factor surveillance system (PASSI). We find that, increasing the accordance between the simulated awareness spreading and the PASSI data on risk perception, the agreement between simulated and experimental epidemiological data improves as well. Furthermore, we show that, within our model, the primary mechanism to reproduce a realistic evolution of the awareness during an epidemic, is the one due to globally available information. This result highlights how crucial is the role of mass media and educational campaigns in influencing the epidemic spreading of infectious diseases. PMID:24376727

Fierro, Annalisa; Liccardo, Antonella

2013-01-01

328

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

329

A model for simulation of Clinical Engineering Department activities.  

PubMed

Clinical Engineering (CE) Departments are in charge of healthcare technology management in healthcare facilities. The workload is proportional to the number of activities, the number and complexity of biomedical instrumentation, and the technology intensity of the facility. Clinical engineers and Biomedical equipment technicians work together in order to perform the different activities and to obtain customer satisfaction. This paper describes a model that can be used to estimate the number of engineers and technicians required to start a new CE Department. The estimation is obtained by means of simulation. Starting by several inputs that describe the facility and the quantity and characteristics of the instruments the model is able to provide the number of Clinical engineers and Biomedical equipment technicians. PMID:19163866

Balestra, Gabriella; Gaetano, Laura; Puppato, Daniele

2008-01-01

330

Development of CFD model for augmented core tripropellant rocket engine  

NASA Astrophysics Data System (ADS)

The Space Shuttle era has made major advances in technology and vehicle design to the point that the concept of a single-stage-to-orbit (SSTO) vehicle appears more feasible. NASA presently is conducting studies into the feasibility of certain advanced concept rocket engines that could be utilized in a SSTO vehicle. One such concept is a tripropellant system which burns kerosene and hydrogen initially and at altitude switches to hydrogen. This system will attain a larger mass fraction because LOX-kerosene engines have a greater average propellant density and greater thrust-to-weight ratio. This report describes the investigation to model the tripropellant augmented core engine. The physical aspects of the engine, the CFD code employed, and results of the numerical model for a single modular thruster are discussed.

Jones, Kenneth M.

1994-10-01

331

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

332

Research Study: Space Shuttle Main Engine Plume Flowfield Model  

NASA Technical Reports Server (NTRS)

The initial research effort was an in-depth analysis of the shuttle main engine plumes in an effort to improve the flowfield model and to enhance shuttle base heating equipment predictions during ascent. A prediction methodology code was developed incorporating the improved plume model into a predictive tool which could consider different trajectoreis and engine perfromance variables. Various plume flow model improvement studies were ongoing at the time of the 51-L accident. Since that time, base heating and plume methodology improvements have continued as part of the overall emphasis on Shuttle design assurance before resuming flight schedule.

Bender, Robert L.

1988-01-01

333

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

334

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

335

Electronic structure modeling in an engineering context (abstract only).  

PubMed

From 1994 through 2005 the US Department of Energy developed advanced thermophotovoltaic devices with world record energy conversion efficiency. I discuss my role as a materials physicist and electronic structure modeler embedded in this engineering development effort, in which I supported device design improvements throughout the project. I then generalize from these and other experiences to discuss the critical interfaces needed between potential electronic structure tool users in engineering organizations in industry and government, and electronic structure tool developers in academia. PMID:21693887

Geller, Clint B

2008-02-13

336

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

NASA Astrophysics Data System (ADS)

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.

1994-07-01

337

Modeling of Human Criminal Behavior using Probabilistic Networks  

E-print Network

Currently, criminals profile (CP) is obtained from investigators or forensic psychologists interpretation, linking crime scene characteristics and an offenders behavior to his or her characteristics and psychological profile. This paper seeks an efficient and systematic discovery of nonobvious and valuable patterns between variables from a large database of solved cases via a probabilistic network (PN) modeling approach. The PN structure can be used to extract behavioral patterns and to gain insight into what factors influence these behaviors. Thus, when a new case is being investigated and the profile variables are unknown because the offender has yet to be identified, the observed crime scene variables are used to infer the unknown variables based on their connections in the structure and the corresponding numerical (probabilistic) weights. The objective is to produce a more systematic and empirical approach to profiling, and to use the resulting PN model as a decision tool.

Pillai, Ramesh Kumar Gopala

2010-01-01

338

Nitrogen oxidizing in modeling of diesel engine operation  

SciTech Connect

A computer model of diesel engine operation based on the interconnected calculation of diesel fuel spray and the processes in the combustion chamber is extended for the calculation of Nitrogen oxidizing. A number of chemical reactions with O{sub 2}, O, N{sub 2}, N, NO, OH, H, H{sub 2} are included in the model.

Kulakov, V.; Merker, G.

1995-12-31

339

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

340

A Team Building Model for Software Engineering Courses Term Projects  

ERIC Educational Resources Information Center

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

Sahin, Yasar Guneri

2011-01-01

341

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

342

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

343

ModelingModeling Behavior, Learning, and SocialBehavior, Learning, and Social Interactions in Dynamic Economic SystemsInteractions in Dynamic Economic Systems  

E-print Network

1 ModelingModeling Behavior, Learning, and SocialBehavior, Learning, and Social Interactions, institutions, behavior, learning, and social interactions in dynamic economic systems A Major Extension performance study 2. An ACE trading world (two-sector growth model) Pluses & minuses of ACE for social science

Tesfatsion, Leigh

344

Model Curriculum For Civil Engineering Technology  

NSDL National Science Digital Library

This project, a project of NSF's Advanced Technological Education program, has developed a civil engineering technology/surveying curriculum for two-year colleges based on an industry survey and review of CET programs around the country. The curriculum integrates new technologies such as GIS, GPS, CADD and computer-aided problem solving into the curriculum. The project is involved in teaching material development, dissemination, and implementation. On the site, visitors will find curriculum documents which include information on developing new course materials, GPS Multimedia Courseware for those using Windows operating systems, as well as information about the project, its partners and sponsors.

2008-08-06

345

Creep-rupture behavior of six candidate Stirling engine superalloys tested in air  

NASA Technical Reports Server (NTRS)

The creep-rupture behavior of six candidate Stirling engine iron-base superalloys was determined in air. The alloys included four wrought alloys (A-286, Alloy 800H, N-155, and 19-9DL) and two cast alloys (CRM-6D and XF-818). The specimens were tested to rupture for times up to 3000 h at 650 to 925 C. Rupture life, t(r) minimum creep rate, and time to 1-percent creep strain t(0.01) were statistically analyzed as a function of stress and temperature. Estimated stress levels at different temperatures to obtain 3500 h t(r) and t(0.01) lives were determined. These data will be compared with similar data being obtained under 15 MPa hydrogen.

Bhattacharyya, S.

1984-01-01

346

Uranus Atmospheric Model for Engineering Application  

NASA Astrophysics Data System (ADS)

The poster/paper describes an atmospheric model for the planet Uranus constructed from published data based upon the Voyager-2 flyby of Uranus in 24 January 1986. This new model is designed for use in atmospheric probe trajectory simulation.

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

2014-06-01

347

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

348

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

PubMed

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

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

2013-10-22

349

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

350

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

351

Modeling Positive Behavior Interventions and Supports for Preservice Teachers  

ERIC Educational Resources Information Center

The authors modeled programwide positive behavior interventions and supports (PBIS) principles to 26 preservice teachers during consolidated yearly extended school year (ESY) services delivered to elementary students from four school districts. While PBIS were in place for preservice teachers to implement with students, a similar system was…

Hill, Doris Adams; Flores, Margaret M.

2014-01-01

352

A Security Domain Model for Implementing Trusted Subject Behaviors  

E-print Network

A Security Domain Model for Implementing Trusted Subject Behaviors Alan Shaffer, Mikhail Auguston secure (MLS) system, trusted subjects are granted privileges to perform operations that are not possible. These subjects are trusted not to conduct malicious activity or degrade system security. We present a formal

353

Safety Assessment Using Behavior Trees and Model Checking  

Microsoft Academic Search

This paper demonstrates the use of Behavior Trees and model checking to assess system safety requirements for a system containing substantial redundancy. The case study concerns the hydraulics systems for the Airbus A320 aircraft, which are critical for aircraft control. The system design is supposed to be able to handle up to 3 different components failing individually, without loss of

Peter A. Lindsay; K. Winter; N. Yatapanage

2010-01-01

354

Development of a Medicaid Behavioral Health Case-Mix Model  

ERIC Educational Resources Information Center

Many Medicaid programs have either fully or partially carved out mental health services. The evaluation of carve-out plans requires a case-mix model that accounts for differing health status across Medicaid managed care plans. This article develops a diagnosis-based case-mix adjustment system specific to Medicaid behavioral health care. Several…

Robst, John

2009-01-01

355

An agent model of social network and travel behavior interdependence  

Microsoft Academic Search

Travel is a prerequisite for activities which maintain social and business connections, building the vital social networks which conduct the flow of values, services, and opportunity. This paper presents a multi-agent simulation to study linked geographical and social spaces. The model simultaneously generates a social network and travel behavior by defining social-networking visits as travel activities. Information about space and

Jeremy Hackney; Kay W. Axhausen

356

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

357

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

358

RESEARCH Open Access Modeling bee swarming behavior through  

E-print Network

RESEARCH Open Access Modeling bee swarming behavior through diffusion adaptation with asymmetric bees or uninformed bees, where the informed bees have some information about the destination while the uninformed bees follow the informed bees. The swarm's movement can be viewed as a network of mobile nodes

Sayed, Ali

359

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

360

Reasoning, Models, and Images: Behavioral Measures and Cortical Activity  

E-print Network

Reasoning, Models, and Images: Behavioral Measures and Cortical Activity Markus Knauff1,3 , Thomas was to investigate the neurocognitive processes of mental imagery in deductive reasoning. Behav- ioral studies slowed the process of reasoning in comparison with control relations, whereas visuospatial and spatial

361

Econometrics, Volume 1: Econometric Modeling of Producer Behavior  

Microsoft Academic Search

The objectives of econometric modeling of producer behavior are to determine the nature of substitution among inputs and outputs and of differences in technology, as well as the role of economies of scale in production. Recent advances in methodology, based on the dual formulation of the theory of production in terms of prices, have enabled econometricians to achieve these objectives

Dale W. Jorgenson

362

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

363

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

364

Acceptance and Commitment Therapy and Contextual Behavioral Science: Examining the Progress of a Distinctive Model of Behavioral and Cognitive Therapy  

Microsoft Academic Search

A number of recent authors have compared acceptance and commitment therapy (ACT) and traditional cognitive behavior therapy (CBT). The present article describes ACT as a distinct and unified model of behavior change, linked to a specific strategy of scientific development, which we term “contextual behavioral science.” We outline the empirical progress of ACT and describe its distinctive development strategy. A

Steven C. Hayes; Michael E. Levin; Jennifer Plumb-Vilardaga; Jennifer L. Villatte; Jacqueline Pistorello

365

Engineering RGD nanopatterned hydrogels to control preosteoblast behavior: a combined computational and experimental approach.  

PubMed

The adhesion ligand arginine-glycine-aspartic acid (RGD) has been coupled to various materials to be used as tissue culture matrices or cell transplantation vehicles, and recent studies indicate that nanopatterning RGD into high-density islands alters key cell behaviors. Previous studies have failed, however, to conclusively decouple the effects of RGD bulk density and individual pattern parameters (i.e. RGDs/island and island distribution) on these altered cell responses. Using a nanopatterned RGD-coupled alginate hydrogel matrix, this work combines computational, statistical and experimental approaches to elucidate the effects of RGD patterns on four key cell responses. This study shows that in MC3T3 preosteoblasts focal adhesion kinase (FAK) Y397 phosphorylation, cell spreading, and osteogenic differentiation can be controlled by RGD nanopatterning, with the distribution of islands throughout the hydrogel (i.e. how closely spaced the islands are) being the most significant pattern parameter. More closely spaced islands favor FAK Y397 phosphorylation and cell spreading, while more widely spaced islands favor differentiation. Proliferation, in contrast, is primarily a function of RGD bulk density. Nanopatterning of cell adhesion ligands has tremendous potential as a simple tool to gain significant control over multiple cell behaviors in engineered extracellular matrix (ECM). PMID:17619056

Comisar, Wendy A; Kazmers, Nikolas H; Mooney, David J; Linderman, Jennifer J

2007-10-01

366

Safety-Driven Model-Based System Engineering Methodology Part I  

E-print Network

Safety-Driven Model-Based System Engineering Methodology Part I: Methodology Description* December....................................................................................................................... 22 3. System Engineering Methodology ............................................................ 45 4. Methodology Conclusion and Summary

Leveson, Nancy

367

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

368

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

369

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 development of fatigue laws suitable for life prediction of Nitinol devices, has conducted an extensive experimental study of the modifications in uniaxial behavior of both Nitinol wire and tubing due to cyclic loading. The Abaqus Nitinol material model has been extended to capture some of the phenomena observed and is described in this article. Namely, a preload beyond 6% strain alters the transformation plateaus; if the cyclic load amplitude is large enough, permanent deformations (residual martensite) are observed; the lower plateau increases; and the upper plateau changes. The modifications to the upper plateau are very interesting in the sense that it appears broken: its start stress gets lowered creating a new plateau up to the highest level of cyclic strain, followed by resuming the original plateau until full transformation. Since quite often the geometry of a device at the point at which it is subjected to cyclic loading is very much dependent on the manufacturing, deployment, and preloading sequence, it is important that analyses be conducted with the original material behavior up to that point, and then with the cyclic behavior thereafter.

Rebelo, Nuno; Zipse, Achim; Schlun, Martin; Dreher, Gael

2011-07-01

370

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

371

A comprehensive model and method for model parameterization for predicting pattern collapse behavior in photoresist nanostructures  

NASA Astrophysics Data System (ADS)

Pattern collapse has become an issue of increasing importance in semiconductor lithography as the size of critical features continues to shrink. Although models have been proposed to explain the observed pattern collapse behavior, the ability of such models to quantitatively predict the collapse behavior has been limited without significant model fitting to experimental pattern collapse behavior. Such a need to collect extensive collapse data before these models can provide any predictive capability limits their use and in general does not provide further insight into the underlying root causes of the observed behavior in many cases. This is particularly true at small feature sizes for resist lines smaller than approximately 70 nm in width. In this work, a comprehensive pattern collapse model that accounts for both adhesion based pattern failure and elastoplastic deformation-based failure is used. Furthermore, the required model parameters are extracted from basic experiments on the resist materials and substrates themselves without the need for actual patterning experiments. For example, the resist mechanical modulus behavior is determined from simple thin film buckling experiments. The results of these simple tests are quantitatively predictive pattern collapse models for a particular resist-substrate combination that capture complex effects such as the dependence of the collapse behavior on resist film thickness and feature size due to feature size dependent polymer modulus behavior. Application of these models and experimental methods to an experimental resist and comparisons of the model predictions versus actual experimental pattern collapse data are shown and discussed to validate the methodology.

Yeh, Wei-Ming; Lawson, Richard A.; Henderson, Clifford L.

2011-04-01

372

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

373

Analytics For Distracted Driver Behavior Modeling in Dilemma Zone  

SciTech Connect

In this paper, we present the results obtained and insights gained through the analysis of TRB contest data. We used exploratory analysis, regression, and clustering models for gaining insights into the driver behavior in a dilemma zone while driving under distraction. While simple exploratory analysis showed the distinguishing driver behavior patterns among different popu- lation groups in the dilemma zone, regression analysis showed statically signification relationships between groups of variables. In addition to analyzing the contest data, we have also looked into the possible impact of distracted driving on the fuel economy.

Li, Jan-Mou [ORNL] [ORNL; Malikopoulos, Andreas [ORNL] [ORNL; Thakur, Gautam [ORNL] [ORNL; Vatsavai, Raju [ORNL] [ORNL

2014-01-01

374

Generalized Rabi model as a quantum Otto engine  

E-print Network

We propose a multilevel quantum heat engine with a working medium described by a generalized Rabi model which consists of a two-level system coupled to a single mode bosonic field. The engine operates in quantum Otto cycle where the working medium is coupled to classical heat baths in the isochoric processes of the four stroke cycle; while either the coupling strength or the resonance frequency is changed in the adiabatic stages. We found that such an engine can produce work with an efficiency close to Carnot bound when it operates at low temperatures and in the ultrastrong coupling regime. We point out that the proposed quantum Otto engine can be implemented experimentally with the modern circuit quantum electrodynamic systems where flux qubits can be coupled ultrastrongly to superconducting transmission line resonators.

Ferdi Altintas; Özgür E. Müstecapl?o?lu

2014-01-20

375

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

376

Modeling and laser-based sensing of pulsed detonation engines  

Microsoft Academic Search

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

Ethan A. Barbour

2009-01-01

377

A Model Driven Domain Engineering Method  

Microsoft Academic Search

This paper proposes an approach of organizing the development of a large software system. By domain analysis and design the method can provide a domain meta-model (DMM) based on the MOF model and a flexible and customizable domain specific software architecture (DSSA). In late domain implementation phase it can make use of DMM and DSSA to generate domain software. The

Bing Li; Shufen Liu

2008-01-01

378

Measuring and Modeling Behavioral Decision Dynamics in Collective Evacuation  

PubMed Central

Identifying and quantifying factors influencing human decision making remains an outstanding challenge, impacting the performance and predictability of social and technological systems. In many cases, system failures are traced to human factors including congestion, overload, miscommunication, and delays. Here we report results of a behavioral network science experiment, targeting decision making in a natural disaster. In a controlled laboratory setting, our results quantify several key factors influencing individual evacuation decision making in a controlled laboratory setting. The experiment includes tensions between broadcast and peer-to-peer information, and contrasts the effects of temporal urgency associated with the imminence of the disaster and the effects of limited shelter capacity for evacuees. Based on empirical measurements of the cumulative rate of evacuations as a function of the instantaneous disaster likelihood, we develop a quantitative model for decision making that captures remarkably well the main features of observed collective behavior across many different scenarios. Moreover, this model captures the sensitivity of individual- and population-level decision behaviors to external pressures, and systematic deviations from the model provide meaningful estimates of variability in the collective response. Identification of robust methods for quantifying human decisions in the face of risk has implications for policy in disasters and other threat scenarios, specifically the development and testing of robust strategies for training and control of evacuations that account for human behavior and network topologies. PMID:24520331

Carlson, Jean M.; Alderson, David L.; Stromberg, Sean P.; Bassett, Danielle S.; Craparo, Emily M.; Guiterrez-Villarreal, Francisco; Otani, Thomas

2014-01-01

379

30 cm Engineering Model thruster design and qualification tests  

NASA Technical Reports Server (NTRS)

Development of a 30-cm mercury electron bombardment Engineering Model ion thruster has successfully brought the thruster from the status of a laboratory experimental device to a point approaching flight readiness. This paper describes the development progress of the Engineering Model (EM) thruster in four areas: (1) design features and fabrication approaches, (2) performance verification and thruster to thruster variations, (3) structural integrity, and (4) interface definition. The design of major subassemblies, including the cathode-isolator-vaporizer (CIV), main isolator-vaporizer (MIV), neutralizer isolator-vaporizer (NIV), ion optical system, and discharge chamber/outer housing is discussed along with experimental results.

Schnelker, D. E.; Collett, C. R.

1975-01-01

380

Materials Science and Engineering A244 (1998) 138144 The vacuum hot pressing behavior of silicon carbide fibers coated  

E-print Network

(VHP) of silicon carbide monofilaments coated with nanocrystalline Ti­6Al­4V has been studied. During; Silicon carbide fibers; Densification 1. Introduction Silicon carbide (SiC) fiber reinforced titaniumMaterials Science and Engineering A244 (1998) 138­144 The vacuum hot pressing behavior of silicon

Wadley, Haydn

381

New Integrated Modeling Capabilities: MIDAS' Recent Behavioral Enhancements  

NASA Technical Reports Server (NTRS)

The Man-machine Integration Design and Analysis System (MIDAS) is an integrated human performance modeling software tool that is based on mechanisms that underlie and cause human behavior. A PC-Windows version of MIDAS has been created that integrates the anthropometric character "Jack (TM)" with MIDAS' validated perceptual and attention mechanisms. MIDAS now models multiple simulated humans engaging in goal-related behaviors. New capabilities include the ability to predict situations in which errors and/or performance decrements are likely due to a variety of factors including concurrent workload and performance influencing factors (PIFs). This paper describes a new model that predicts the effects of microgravity on a mission specialist's performance, and its first application to simulating the task of conducting a Life Sciences experiment in space according to a sequential or parallel schedule of performance.

Gore, Brian F.; Jarvis, Peter A.

2005-01-01

382

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

383

Modeling the dissolution behavior of standard clays in seawater  

SciTech Connect

The present investigation tests a model to explain the behavior of dissolved Si during early diagenesis in sediments. The model assumes that low-Fe clays and other minerals can be treated simply as Al hydroxides, having attached silica. When the minerals are placed in seawater solutions, Si is released, causing exposure of fresh Al-octahedra, which are reactive toward Si and other elements in solution. Standard clays (kaolinite, montmorillonite) and solid silicic acid were suspended in seawater solutions in various combinations, and dissolved Al, Si, Ca, pH and alkalinity were determined as a function of time. The theoretical model correctly predicts the behavior of Si in mixtures of the different minerals, based upon the dissolution behavior of the minerals in suspension alone. Further, the decrease in the alkalinity of kaolinite-containing seawater solutions, where carbonate dissolution, organic matter decomposition and reduced sulfur oxidation are apparently unimportant, can be predicted from a simple extrapolation of the silica model results. The alkalinity changes observed in this study, as well as the pH changes observed in standard clay suspensions by other researchers, can be explained simply by equilibration of the charge on exposed Al-octahedra with the pH of the surrounding waters. The results of this study indicate that theoretical models of Si diagenesis in sediments should have general usefulness for predicting the effects of clay dissolution on sediment properties.

Mackin, J.E.; Swider, K.T. (State Univ. of New York, Stony Brook (USA))

1987-11-01

384

Hysteretic Behavior of Prestressed Concrete Bridge Pier with Fiber Model  

PubMed Central

The hysteretic behavior and seismic characteristics of the prestressed concrete bridge pier were researched. The effects of the prestressed tendon ratio, the longitudinal reinforcement ratio, and the stirrup reinforcement ratio on the hysteretic behavior and seismic characteristics of the prestressed concrete bridge pier have been obtained with the fiber model analysis method. The analysis show some results about the prestressed concrete bridge pier. Firstly, greater prestressed tendon ratio and more longitudinal reinforcement can lead to more obvious pier's hysteresis loop “pinching effect,” smaller residual displacement, and lower energy dissipation capacity. Secondly, the greater the stirrup reinforcement ratio is, the greater the hysteresis loop area is. That also means that bridge piers will have better ductility and stronger shear capacity. The results of the research will provide a theoretical basis for the hysteretic behavior analysis of the prestressed concrete pier. PMID:24578635

Hui-li, Wang; Guang-qi, Feng; Si-feng, Qin

2014-01-01

385

A finite element model for shape memory behavior  

NASA Astrophysics Data System (ADS)

This paper deals with a finite element implementation concerning the shape memory behavior. Shape memory behavior is usually driven by temperature changes. This model allows the simulation of problems integrating complex mechanical loading effects under random temperature variations. According to the relationship between stress and strain, the shape fixation during cooling phases and the memory effect during heating phase are modelised through a hereditary behavior needing incremental formulation developments. The step by step process introduces an additional fixed stress. Simulations request, for complex geometries including boundary conditions, a finite element approach. Thermodynamic developments are presented in order to define energetic balance and dissipations. In this paper, we propose to generalize this dependence of elastic modulus variations. A formulation for random mechanical loading and temperature variations is proposed. An experimental validation is proposed about shape memory alloy polymer DP5.

Husson, Jean Marie; Dubois, Frédéric; Sauvat, Nicolas

2011-08-01

386

Modeling the behavior of a type-319 aluminum alloy during quenching  

NASA Astrophysics Data System (ADS)

Desired weight savings in automobiles has led to an increase in the use of cast aluminum parts in engine applications. To achieve the strength required in these applications, parts must be heat treated prior to service. This heat treatment involves a severe quench that can cause large thermal gradients, leading to undesirable residual stresses and strains. The ability to predict accurately residual stress and strain development during the quench would allow the design of aluminum engine parts with increased fatigue resistance and higher geometric tolerances. In this work, the behavior of a type-319 cast aluminum alloy (W319) is studied, from the equilibrium solid-solution state, to the end of the quench. A mechanical threshold stress model is used to predict the onset of plastic deformation in quenched parts due to effects of temperature and strain rate. The evolution of this mechanical threshold follows a Voce Law formulation. Parameters of the model are derived from rapid, uniaxial tension tests conducted on samples cast in green sand. The model is used in a one-dimensional, semi-analytical solution to predict the deformation and residual stress of side-quenched aluminum beams of uniform cross section. The model is also applied in full three-dimensional form to predict the behavior of beams of a non-uniform cross section. Model results are compared to results of quenching experiments performed on cast aluminum beams, including both transient deformation measurements and residual stress measurements obtained by a layer-removal technique. It is found that residual stress is predicted reasonably well by the model and that the model converges acceptably quickly to a solution when applied in a three-dimensional finite-element analysis. Transient and residual deformation are found to be more difficult to predict than residual stress.

Newman, Matthew Lloyd

387

A Comparison of Three Approaches to Model Human Behavior  

NASA Astrophysics Data System (ADS)

One way of studying social processes is through the use of simulations. The use of simulations for this purpose has been established as its own field, social simulations, and has been used for studying a variety of phenomena. A simulation of a social setting can serve as an aid for thinking about that social setting, and for experimenting with different parameters and studying the outcomes caused by them. When using the simulation as an aid for thinking and experimenting, the chosen simulation approach will implicitly steer the simulationist towards thinking in a certain fashion in order to fit the model. To study the implications of model choice on the understanding of a setting where human anticipation comes into play, a simulation scenario of a coffee room was constructed using three different simulation approaches: Cellular Automata, Systems Dynamics and Agent-based modeling. The practical implementations of the models were done in three different simulation packages: Stella for Systems Dynamic, CaFun for Cellular automata and SesAM for Agent-based modeling. The models were evaluated both using Randers' criteria for model evaluation, and through introspection where the authors reflected upon how their understanding of the scenario was steered through the model choice. Further the software used for implementing the simulation models was evaluated, and practical considerations for the choice of software package are listed. It is concluded that the models have very different strengths. The Agent-based modeling approach offers the most intuitive support for thinking about and modeling a social setting where the behavior of the individual is in focus. The Systems Dynamics model would be preferable in situations where populations and large groups would be studied as wholes, but where individual behavior is of less concern. The Cellular Automata models would be preferable where processes need to be studied from the basis of a small set of very simple rules. It is further concluded that in most social simulation settings the Agent-based modeling approach would be the probable choice. This since the other models does not offer much in the way of supporting the modeling of the anticipatory behavior of humans acting in an organization.

Palmius, Joel; Persson-Slumpi, Thomas

2010-11-01

388

A transport model for prediction of wildfire behavior  

SciTech Connect

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 not have self-determining propagation rates. The author uses a transport approach to represent this complicated problem and produce a model that utilizes a self-determining propagation rate. The transport approach allows one to represent a large number of environments including transition regions such as those with nonhomogeneous vegetation and terrain. Some of the most difficult features to treat are the imperfectly known boundary conditions and the fine scale structure that is unresolvable, such as the specific location of the fuel or the precise incoming winds. The author accounts for the microscopic details of a fire with macroscopic resolution by dividing quantities into mean and fluctuating parts similar to what is done in traditional turbulence modelling. The author develops a complicated model that includes the transport of multiple gas species, such as oxygen and volatile hydrocarbons, and tracks the depletion of various fuels and other stationary solids and liquids. From this model the author also forms a simplified local burning model with which he performs a number of simulations for the purpose of demonstrating the properties of a self-determining transport-based wildfire model.

Linn, R.R.

1997-07-01

389

EHF (Extremely High Frequency) telecommunications system engineering model  

NASA Astrophysics Data System (ADS)

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

Allen, K. C.

1986-04-01

390

Modeling equine race surface vertical mechanical behaviors in a musculoskeletal modeling environment.  

PubMed

Race surfaces have been associated with the incidence of racehorse musculoskeletal injury, the leading cause of racehorse attrition. Optimal race surface mechanical behaviors that minimize injury risk are unknown. Computational models are an economical method to determine optimal mechanical behaviors. Previously developed equine musculoskeletal models utilized ground reaction floor models designed to simulate a stiff, smooth floor appropriate for a human gait laboratory. Our objective was to develop a computational race surface model (two force-displacement functions, one linear and one nonlinear) that reproduced experimental race surface mechanical behaviors for incorporation in equine musculoskeletal models. Soil impact tests were simulated in a musculoskeletal modeling environment and compared to experimental force and displacement data collected during initial and repeat impacts at two racetracks with differing race surfaces - (i) dirt and (ii) synthetic. Best-fit model coefficients (7 total) were compared between surface types and initial and repeat impacts using a mixed model ANCOVA. Model simulation results closely matched empirical force, displacement and velocity data (Mean R(2)=0.930-0.997). Many model coefficients were statistically different between surface types and impacts. Principal component analysis of model coefficients showed systematic differences based on surface type and impact. In the future, the race surface model may be used in conjunction with previously developed the equine musculoskeletal models to understand the effects of race surface mechanical behaviors on limb dynamics, and determine race surface mechanical behaviors that reduce the incidence of racehorse musculoskeletal injury through modulation of limb dynamics. PMID:25634662

Symons, Jennifer E; Fyhrie, David P; Hawkins, David A; Upadhyaya, Shrinivasa K; Stover, Susan M

2015-02-26

391

Behavioral models of tinnitus and hyperacusis in animals.  

PubMed

The phantom perception of tinnitus and reduced sound-level tolerance associated with hyperacusis have a high comorbidity and can be debilitating conditions for which there are no widely accepted treatments. One factor limiting the development of treatments for tinnitus and hyperacusis is the lack of reliable animal behavioral models of these disorders. Therefore, the purpose of this review is to highlight the current animal models of tinnitus and hyperacusis, and to detail the advantages and disadvantages of each paradigm. To date, this is the first review to include models of both tinnitus and hyperacusis. PMID:25278931

Hayes, Sarah H; Radziwon, Kelly E; Stolzberg, Daniel J; Salvi, Richard J

2014-01-01

392

Behavioral Models of Tinnitus and Hyperacusis in Animals  

PubMed Central

The phantom perception of tinnitus and reduced sound-level tolerance associated with hyperacusis have a high comorbidity and can be debilitating conditions for which there are no widely accepted treatments. One factor limiting the development of treatments for tinnitus and hyperacusis is the lack of reliable animal behavioral models of these disorders. Therefore, the purpose of this review is to highlight the current animal models of tinnitus and hyperacusis, and to detail the advantages and disadvantages of each paradigm. To date, this is the first review to include models of both tinnitus and hyperacusis. PMID:25278931

Hayes, Sarah H.; Radziwon, Kelly E.; Stolzberg, Daniel J.; Salvi, Richard J.

2014-01-01

393

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

394

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

NASA Technical Reports Server (NTRS)

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

Tew, Roy C., Jr.

1988-01-01

395

Modeling the viscoplastic behavior of Inconel 718 at 1200 F  

NASA Technical Reports Server (NTRS)

A large number of tests, including tensile, creep, fatigue, and creep-fatigue were performed to characterize the mechanical properties of Inconel 718 (a nickel based superalloy) at 1200 F, the operating temperature for turbine blades. In addition, a few attempts were made to model the behavior of Inconel 718 at 1200 F using viscoplastic theories. The Chaboche theory of viscoplasticity can model a wide variety of mechanical behavior, including monotonic, sustained, and cyclic responses of homogeneous, initially-isotropic, strain hardening (or softening) materials. It is shown how the Chaboche theory can be used to model the viscoplastic behavior of Inconel 718 at 1200 F. First, an algorithm was developed to systematically determine the material parameters of the Chaboche theory from uniaxial tensile, creep, and cyclic data. The algorithm is general and can be used in conjunction with similar high temperature materials. A sensitivity study was then performed and an optimal set of Chaboche's parameters were obtained. This study has also indicated the role of each parameter in modeling the response to different loading conditions.

Abdel-Kader, M. S.; Eftis, J.; Jones, D. L.

1988-01-01

396

Modeling bistable behaviors in morphing structures through finite element simulations.  

PubMed

Bistable structures, exemplified by the Venus flytrap and slap bracelets, can transit between different configurations upon certain external stimulation. Here we study, through three-dimensional finite element simulations, the bistable behaviors in elastic plates in the absence of terminate loads, but with pre-strains in one (or both) of the two composite layers. Both the scenarios with and without a given geometric mis-orientation angle are investigated, the results of which are consistent with recent theoretical and experimental studies. This work can open ample venues for programmable designs of plant/shell structures with large deformations, with applications in designing bio-inspired robotics for biomedical research and morphing/deployable structures in aerospace engineering. PMID:24211939

Guo, Qiaohang; Zheng, Huang; Chen, Wenzhe; Chen, Zi

2014-01-01

397

Key Reliability Drivers of Liquid Propulsion Engines and A Reliability Model for Sensitivity Analysis  

NASA Technical Reports Server (NTRS)

This paper is to address the in-flight reliability of a liquid propulsion engine system for a launch vehicle. We first establish a comprehensive list of system and sub-system reliability drivers for any liquid propulsion engine system. We then build a reliability model to parametrically analyze the impact of some reliability parameters. We present sensitivity analysis results for a selected subset of the key reliability drivers using the model. Reliability drivers identified include: number of engines for the liquid propulsion stage, single engine total reliability, engine operation duration, engine thrust size, reusability, engine de-rating or up-rating, engine-out design (including engine-out switching reliability, catastrophic fraction, preventable failure fraction, unnecessary shutdown fraction), propellant specific hazards, engine start and cutoff transient hazards, engine combustion cycles, vehicle and engine interface and interaction hazards, engine health management system, engine modification, engine ground start hold down with launch commit criteria, engine altitude start (1 in. start), Multiple altitude restart (less than 1 restart), component, subsystem and system design, manufacturing/ground operation support/pre and post flight check outs and inspection, extensiveness of the development program. We present some sensitivity analysis results for the following subset of the drivers: number of engines for the propulsion stage, single engine total reliability, engine operation duration, engine de-rating or up-rating requirements, engine-out design, catastrophic fraction, preventable failure fraction, unnecessary shutdown fraction, and engine health management system implementation (basic redlines and more advanced health management systems).

Huang, Zhao-Feng; Fint, Jeffry A.; Kuck, Frederick M.

2005-01-01

398

A comprehensive combustion model for biodiesel-fueled engine simulations  

NASA Astrophysics Data System (ADS)

Engine models for alternative fuels are available, but few are comprehensive, well-validated models that include accurate physical property data as well as a detailed description of the fuel chemistry. In this work, a comprehensive biodiesel combustion model was created for use in multi-dimensional engine simulations, specifically the KIVA3v R2 code. The model incorporates realistic physical properties in a vaporization model developed for multi-component fuel sprays and applies an improved mechanism for biodiesel combustion chemistry. A reduced mechanism was generated from the methyl decanoate (MD) and methyl-9-decenoate (MD9D) mechanism developed at Lawrence Livermore National Laboratory. It was combined with a multi-component mechanism to include n-heptane in the fuel chemistry. The biodiesel chemistry was represented using a combination of MD, MD9D and n-heptane, which varied for a given fuel source. The reduced mechanism, which contained 63 species, accurately predicted ignition delay times of the detailed mechanism over a range of engine-specific operating conditions. Physical property data for the five methyl ester components of biodiesel were added to the KIVA library. Spray simulations were performed to ensure that the models adequately reproduce liquid penetration observed in biodiesel spray experiments. Fuel composition impacted liquid length as expected, with saturated species vaporizing more and penetrating less. Distillation curves were created to ensure the fuel vaporization process was comparable to available data. Engine validation was performed against a low-speed, high-load, conventional combustion experiments and the model was able to predict the performance and NOx formation seen in the experiment. High-speed, low-load, low-temperature combustion conditions were also modeled, and the emissions (HC, CO, NOx) and fuel consumption were well-predicted for a sweep of injection timings. Finally, comparisons were made between the results of biodiesel composition (palm vs. soy) and fuel blends (neat vs. B20). The model effectively reproduced the trends observed in the experiments.

Brakora, Jessica L.

399

Genetically Engineered Mouse Models of Prostate Cancer  

Microsoft Academic Search

ObjectivesMouse models of prostate cancer are used to test the contribution of individual genes to the transformation process, evaluate the collaboration between multiple genetic lesions observed in a single tumour, and perform preclinical intervention studies in prostate cancer research.

Martijn C. Nawijn; Andreas M. Bergman; Henk G. van der Poel

2008-01-01

400

A new accident model for engineering safer systems  

Microsoft Academic Search

New technology is making fundamental changes in the etiology of accidents and is creating a need for changes in the explanatory mechanisms used. We need better and less subjective understanding of why accidents occur and how to prevent future ones. The most effective models will go beyond assigning blame and instead help engineers to learn as much as possible about

Nancy Leveson

2004-01-01

401

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

SciTech Connect

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

Not Available

2011-09-01

402

Numerical modeling of hydrogen-fueled internal combustion engines  

SciTech Connect

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

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

1996-12-31

403

Computer model of catalytic combustion/Stirling engine heater head  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

404

Engineering Models for Titan's Atmosphere R. V. Yelle1  

E-print Network

Engineering Models for Titan's Atmosphere R. V. Yelle1 , D. F. Strobell,2 E. Lellouch3 & D. Gautier's atmospheric structure used in the design and analysis of the Huygens Probe and its mission. It supersedes in this volume). There has been significant progress in our under-standing of Titan's atmosphere in the last few

Yelle, Roger V.

405

Form Follows Function Model-Driven Engineering for Clinical Trials  

E-print Network

Form Follows Function Model-Driven Engineering for Clinical Trials Jim Davies1 , Jeremy Gibbons1 tools to support clinical trials. A domain metamodel captures the community's best practice in trial of view, a clinical trial is largely an exercise in data management: observations have to be specified

Jeavons, Peter

406

A New Accident Model for Engineering Safer Systems Nancy Leveson  

E-print Network

A New Accident Model for Engineering Safer Systems Nancy Leveson Aeronautics and Astronautics Dept changes in the etiology of accidents and is creating a need for changes in the explanatory mechanisms used. We need better and less subjective understanding of why accidents occur and how to prevent future

Leveson, Nancy

407

Forebay Computational Fluid Dynamics Modeling for The Dalles Dam to Support Behavior Guidance System Siting Studies  

SciTech Connect

Computational fluid dynamics (CFD) models were developed to support the siting and design of a behavioral guidance system (BGS) structure in The Dalles Dam (TDA) forebay on the Columbia River. The work was conducted by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers, Portland District (CENWP). The CFD results were an invaluable tool for the analysis, both from a Regional and Agency perspective (for the fish passage evaluation) and a CENWP perspective (supporting the BGS design and location). The new CFD model (TDA forebay model) included the latest bathymetry (surveyed in 1999) and a detailed representation of the engineered structures (spillway, powerhouse main, fish, and service units). The TDA forebay model was designed and developed in a way that future studies could easily modify or, to a large extent, reuse large portions of the existing mesh. This study resulted in these key findings: (1) The TDA forebay model matched well with field-measured velocity data. (2) The TDA forebay model matched observations made at the 1:80 general physical model of the TDA forebay. (3) During the course of this study, the methodology typically used by CENWP to contour topographic data was shown to be inaccurate when applied to widely-spaced transect data. Contouring methodologies need to be revisited--especially before such things as modifying the bathymetry in the 1:80 general physical model are undertaken. Future alignments can be evaluated with the model staying largely intact. The next round of analysis will need to address fish passage demands and navigation concerns. CFD models can be used to identify the most promising locations and to provide quantified metrics for biological, hydraulic, and navigation criteria. The most promising locations should then be further evaluated in the 1:80 general physical model.

Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.; Johnson, Gary E.

2005-03-10

408

Modeling of powder behavior: Report for Phase 2 feasibility  

SciTech Connect

We report on a Phase 2 feasibility study of an effort to compute the mechanical behavior of the incendiary powder RS41 during compaction and release using the experiments conducted at China Lake as a data base. Our simulation, using a prototype material model, develops two-dimensional density gradients in even these simple, uniaxial double-piston experiments. In our view, the computational simulation of the behavior of RS41 while press loading this material into a round and under subsequent launch conditions is feasible within the framework of current technology. For the model development that was conducted as part of this feasibility study, the code of choice was the implicit Lagrangian hydro code NIKE2D. The applicability of the explicit companion code DYNA2D is also discussed.

Sinz, K,; Lassila, D.H.; Baum, D.W.

1996-01-01

409

Approaches to Validation of Models for Low Gravity Fluid Behavior  

NASA Technical Reports Server (NTRS)

This paper details the author experiences with the validation of computer models to predict low gravity fluid behavior. It reviews the literature of low gravity fluid behavior as a starting point for developing a baseline set of test cases. It examines authors attempts to validate their models against these cases and the issues they encountered. The main issues seem to be that: Most of the data is described by empirical correlation rather than fundamental relation; Detailed measurements of the flow field have not been made; Free surface shapes are observed but through thick plastic cylinders, and therefore subject to a great deal of optical distortion; and Heat transfer process time constants are on the order of minutes to days but the zero-gravity time available has been only seconds.

Chato, David J.; Marchetta, Jeffery; Hochstein, John I.; Kassemi, Mohammad

2005-01-01

410

Requirements engineering for cross-sectional information chain models  

PubMed Central

Despite the wealth of literature on requirements engineering, little is known about engineering very generic, innovative and emerging requirements, such as those for cross-sectional information chains. The IKM health project aims at building information chain reference models for the care of patients with chronic wounds, cancer-related pain and back pain. Our question therefore was how to appropriately capture information and process requirements that are both generally applicable and practically useful. To this end, we started with recommendations from clinical guidelines and put them up for discussion in Delphi surveys and expert interviews. Despite the heterogeneity we encountered in all three methods, it was possible to obtain requirements suitable for building reference models. We evaluated three modelling languages and then chose to write the models in UML (class and activity diagrams). On the basis of the current project results, the pros and cons of our approach are discussed. PMID:24199080

Hübner, U; Cruel, E; Gök, M; Garthaus, M; Zimansky, M; Remmers, H; Rienhoff, O

2012-01-01

411

A highly efficient semiphenomenological model of a half-sarcomere for real-time prediction of mechanical behavior.  

PubMed

With existent biomechanical models of skeletal muscle, challenges still exist in implementing real-time predictions for contraction statuses that are particularly significant to biomechanical and biomedical engineering. Because of this difficulty, this paper proposed a decoupled scheme of the links involved in the working process of a sarcomere and established a semiphenomenological model integrating both linear and nonlinear frames of no higher than a second-order system. In order to facilitate engineering application and cybernetics, the proposed model contains a reduced number of parameters and no partial differential equation, making it highly concise and computationally efficient. Through the simulations of various contraction modes, including isometric, isotonic, successive stretch and release, and cyclic contractions, the correctness and efficiency of the model, are validated. Although this study targets half-sarcomeres, the proposed model can be easily extended to describe the larger-scale mechanical behavior of a muscle fiber or a whole muscle. PMID:25210775

Chen, Xing; Yin, Yue Hong

2014-12-01

412

Modeling Social Networks through User Background and Behavior  

Microsoft Academic Search

\\u000a We propose a generative model for social networks, both undirected and directed, that takes into account two fundamental characteristics\\u000a of the user: background (specifically, the real world groups to which the user belongs); and behavior (namely, the ways in\\u000a which the user engages in surfing activity and occasionally adds links to other users encountered this way). Our experiments\\u000a show that

Ilias Foudalis; Kamal Jain; Christos Papadimitriou; Martha Sideri

413

Enhanced Fan Noise Modeling for Turbofan Engines  

NASA Technical Reports Server (NTRS)

This report describes work by consultants to Diversitech Inc. for the NASA Glenn Research Center (GRC) to revise the fan noise prediction procedure based on fan noise data obtained in the 9- by 15 Foot Low-Speed Wind Tunnel at GRC. The purpose of this task is to begin development of an enhanced, analytical, more physics-based, fan noise prediction method applicable to commercial turbofan propulsion systems. The method is to be suitable for programming into a computational model for eventual incorporation into NASA's current aircraft system noise prediction computer codes. The scope of this task is in alignment with the mission of the Propulsion 21 research effort conducted by the coalition of NASA, state government, industry, and academia to develop aeropropulsion technologies. A model for fan noise prediction was developed based on measured noise levels for the R4 rotor with several outlet guide vane variations and three fan exhaust areas. The model predicts the complete fan noise spectrum, including broadband noise, tones, and for supersonic tip speeds, combination tones. Both spectra and directivity are predicted. Good agreement with data was achieved for all fan geometries. Comparisons with data from a second fan, the ADP fan, also showed good agreement.

Krejsa, Eugene A.; Stone, James R.

2014-01-01

414

Initial test results using the GEOS-3 engineering model altimeter  

NASA Technical Reports Server (NTRS)

Data from a series of experimental tests run on the engineering model of the GEOS 3 radar altimeter using the Test and Measurement System (TAMS) designed for preflight testing of the radar altimeter are presented. These tests were conducted as a means of preparing and checking out a detailed test procedure to be used in running similar tests on the GEOS 3 protoflight model altimeter systems. The test procedures and results are also included.

Hayne, G. S.; Clary, J. B.

1977-01-01

415

Soot Emission Modelization of a Diesel Engine from Experimental Data  

Microsoft Academic Search

\\u000a In recent years particulate diesel engines emission analysis has become crucial. Indeed the particulate modelling and experimental\\u000a analysis has been modest, mostly because the lack of adequate measurement instruments and the greater focus on the efficiency.\\u000a Today many instruments can measure accurately the soot emissions and numerous models are in developing. This paper shows the\\u000a experimental results of a soot

Enrico Bocci; Lorenzo Rambaldi

416

Effective modeling and simulation of internal combustion engine control systems  

Microsoft Academic Search

The paper presents an integrated software-hardware solution to effectively model and simulate internal combustion engine control systems. The solution is based on RT-LABTM. The characteristics of the proposed modeling and simulation approach are the preservation of accuracy in the face of relatively large fixed simulation steps and the achievement of real-time and faster than real-time simulation execution. The results of

C. A. Rabbath; H. Desira; K. Butts

2001-01-01

417

TVC actuator model. [for the space shuttle main engine  

NASA Technical Reports Server (NTRS)

A prototype Space Shuttle Main Engine (SSME) Thrust Vector Control (TVC) Actuator analog model was successfully completed. The prototype, mounted on five printed circuit (PC) boards, was delivered to NASA, checked out and tested using a modular replacement technique on an analog computer. In all cases, the prototype model performed within the recording techniques of the analog computer which is well within the tolerances of the specifications.

Baslock, R. W.

1977-01-01

418

An information propagation model considering incomplete reading behavior in microblog  

NASA Astrophysics Data System (ADS)

Microblog is one of the most popular communication channels on the Internet, and has already become the third largest source of news and public opinions in China. Although researchers have studied the information propagation in microblog using the epidemic models, previous studies have not considered the incomplete reading behavior among microblog users. Therefore, the model cannot fit the real situations well. In this paper, we proposed an improved model entitled Microblog-Susceptible-Infected-Removed (Mb-SIR) for information propagation by explicitly considering the user's incomplete reading behavior. We also tested the effectiveness of the model using real data from Sina Microblog. We demonstrate that the new proposed model is more accurate in describing the information propagation in microblog. In addition, we also investigate the effects of the critical model parameters, e.g., reading rate, spreading rate, and removed rate through numerical simulations. The simulation results show that, compared with other parameters, reading rate plays the most influential role in the information propagation performance in microblog.

Su, Qiang; Huang, Jiajia; Zhao, Xiande

2015-02-01

419

Simplified simulation models for control studies of turbojet engines  

NASA Technical Reports Server (NTRS)

The essential dynamical characteristics of a simple single spool turbojet engine were determined through simulation of low order system models on an analog computer. An accurate model was studied and system complexity was reduced through various linearizations and approximations. A derivation of a seventh order simplified simulation model is presented with a derivation of an even simpler third order model, and simulation results from each. The control problem studied is one of getting from zero fuel flow equilibrium to a high thrust equilibrium while taking into account surge margin and turbine inlet temperature constraints.

Brennan, T. C.; Leake, R. J.

1975-01-01

420

Nonlinear Model Predictive Control of an Aircraft Gas Turbine Engine Brent. J. Brunell  

E-print Network

be used for propulsion as aircraft engines and for power generation in land based power systems. The gasNonlinear Model Predictive Control of an Aircraft Gas Turbine Engine Brent. J. Brunell , Robert R aircraft engine model. Strong nonlinearities are present in turbojet aircraft engines due to the large

Bitmead, Bob

421

Interoperability between a dynamic reliability modeling and a Systems Engineering process Principles and Case Study  

E-print Network

Page 1/10 Interoperability between a dynamic reliability modeling and a Systems Engineering process, and combination of various engineering activities. A sound Systems Engineering process, benefiting from. The article explains how, on the basis of Systems Engineering (SE) process definitions, a Meta-model defines

Paris-Sud XI, Université de

422

Modeling micro-electronics drill bit behavior with ABAQUS Standard  

SciTech Connect

Modeling of drill bit behavior under applied forces as well as modeling of the drilling process itself can aid in the understanding of the relative importance of the various drill bit process parameters and can eventually lead to improved drill bit designs. In this paper the authors illustrate the application of ABAQUS Standard to the stress and deformation analysis of micro-electronics drill bits that are used in manufacturing printed circuit boards. Effects of varying point geometry, web taper and flute length on the stress and deformation in a drill bit are illustrated.

Anderson, C.A. [Los Alamos National Lab., NM (United States); Ricketson, E. [Tycom Corp. (United States)

1997-06-01

423

Modeling of the viscoelastic mechano-sorptive behavior in wood  

NASA Astrophysics Data System (ADS)

This paper focuses on the modeling of linearly viscoelastic, mechano-sorptive behavior and its effects during moisture content changes in timber. A generalized Kelvin-Voigt model integrating specific hygro-lock springs is developed and associated, in series, with a shrinkage-swelling element. The coupling between moisture content state and mechanical state implies an evolution in rheological parameters. This alternative approach leads to incorporating strain blockings during the drying period as well as memory effects during wetting phases after unloading. An incremental formulation is also established using a finite-element software, and, moreover, an experimental validation from tensile creep-recovery tests is presented.

Dubois, Frédéric; Husson, Jean-Marie; Sauvat, Nicolas; Manfoumbi, Nicaise

2012-11-01

424

Predictive models of procedural human supervisory control behavior  

NASA Astrophysics Data System (ADS)

Human supervisory control systems are characterized by the computer-mediated nature of the interactions between one or more operators and a given task. Nuclear power plants, air traffic management and unmanned vehicles operations are examples of such systems. In this context, the role of the operators is typically highly proceduralized due to the time and mission-critical nature of the tasks. Therefore, the ability to continuously monitor operator behavior so as to detect and predict anomalous situations is a critical safeguard for proper system operation. In particular, such models can help support the decision J]l8king process of a supervisor of a team of operators by providing alerts when likely anomalous behaviors are detected By exploiting the operator behavioral patterns which are typically reinforced through standard operating procedures, this thesis proposes a methodology that uses statistical learning techniques in order to detect and predict anomalous operator conditions. More specifically, the proposed methodology relies on hidden Markov models (HMMs) and hidden semi-Markov models (HSMMs) to generate predictive models of unmanned vehicle systems operators. Through the exploration of the resulting HMMs in two distinct single operator scenarios, the methodology presented in this thesis is validated and shown to provide models capable of reliably predicting operator behavior. In addition, the use of HSMMs on the same data scenarios provides the temporal component of the predictions missing from the HMMs. The final step of this work is to examine how the proposed methodology scales to more complex scenarios involving teams of operators. Adopting a holistic team modeling approach, both HMMs and HSMMs are learned based on two team-based data sets. The results show that the HSMMs can provide valuable timing information in the single operator case, whereas HMMs tend to be more robust to increased team complexity. In addition, this thesis discusses the methodological and practical limitations of the proposed approach notably in terms of input data requirements and model complexity. This thesis thus provides theoretical and practical contributions by exploring the validity of using statistical models of operators as the basis for detecting and predicting anomalous conditions. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs@mit.edu)

Boussemart, Yves

425

A risk analysis model in concurrent engineering product development.  

PubMed

Concurrent engineering has been widely accepted as a viable strategy for companies to reduce time to market and achieve overall cost savings. This article analyzes various risks and challenges in product development under the concurrent engineering environment. A three-dimensional early warning approach for product development risk management is proposed by integrating graphical evaluation and review technique (GERT) and failure modes and effects analysis (FMEA). Simulation models are created to solve our proposed concurrent engineering product development risk management model. Solutions lead to identification of key risk controlling points. This article demonstrates the value of our approach to risk analysis as a means to monitor various risks typical in the manufacturing sector. This article has three main contributions. First, we establish a conceptual framework to classify various risks in concurrent engineering (CE) product development (PD). Second, we propose use of existing quantitative approaches for PD risk analysis purposes: GERT, FMEA, and product database management (PDM). Based on quantitative tools, we create our approach for risk management of CE PD and discuss solutions of the models. Third, we demonstrate the value of applying our approach using data from a typical Chinese motor company. PMID:20840492

Wu, Desheng Dash; Kefan, Xie; Gang, Chen; Ping, Gui

2010-09-01

426

System Modeling of Gas Engine Driven Heat Pump  

SciTech Connect

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

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

2012-01-01

427

Modeling Spitsbergen fjords by hydrodynamic MIKE engine.  

NASA Astrophysics Data System (ADS)

Two Svalbard's fjords - Hornsund (on the western side of the most southern part of Spitsbergen island) and Kongsfjorden (also on the western side of Spitsbergen island, but in the northern part) are quite different - the first one is "cold" and second one is "warm". It is obvious that both of them are under influence of West Spitsbergen Current (WSC), which curry out warm Atlantic water and cold East Spitsbergen Current detaches Hornsund. But there is also freshwater stored in Spitsbergen glaciers that have strong influence on local hydrology and physical fjord conditions. Both, local and shelf conditions have impact on state of the fjord and there is no answer which one is the most important in each fjord. Modeling could help to solve this problem - MIKE 3D model has been implemented for both fjords. Mesh-grid of the each fjord has been extended for covering shelf area. External forces like tides, velocities at the boundary and atmospheric forces together with sources of cold and dens fresh water in the fjords will give reliable representation of physical conditions in Hornsund and Kongsfjorden. Calculations of balances between cold fresh water and warm and salt will provide additional information that could help to answer the main question of the GAME (Growing of the Arctic Marine Ecosystem) project - what is the reaction of physically controlled Arctic marine ecosystem to temperature rise.

Kosecki, Szymon; Przyborska, Anna; Jakacki, Jaromir

2013-04-01

428

Intelligent Computing for the Management of Changes in Industrial Engineering Modeling Processes  

Microsoft Academic Search

Advancements in engineering modeling have changed work of engineers during the last two decades. Sophisticated descriptions store information about shape oriented engineering objects and their relationships. Boundary representations of form features constitute shape models. Rules and checks have replaced simple data form of shape model entity attributes. This change of modeling facilitates a next step towards application of computer intelligence

László Horváth; Imre J. Rudas; János F. Bitó; Gerhard P. Hancke

2005-01-01

429

Control-Oriented Linear Parameter-Varying Modelling of a Turbocharged Diesel Engine  

E-print Network

Control-Oriented Linear Parameter-Varying Modelling of a Turbocharged Diesel Engine Merten Jung-- In this paper, a third order nonlinear model of the airpath of a turbocharged diesel engine is derived, which nonlinear airpath model of the diesel engine will be described in Section III. The model will be derived

Cambridge, University of

430

Hybrid Model Predictive Control for Sequential Decision Policies in Adaptive Behavioral Interventions  

PubMed Central

Control engineering offers a systematic and efficient method to optimize the effectiveness of individually tailored treatment and prevention policies known as adaptive or “just-in-time” behavioral interventions. The nature of these interventions requires assigning dosages at categorical levels, which has been addressed in prior work using Mixed Logical Dynamical (MLD)-based hybrid model predictive control (HMPC) schemes. However, certain requirements of adaptive behavioral interventions that involve sequential decision making have not been comprehensively explored in the literature. This paper presents an extension of the traditional MLD framework for HMPC by representing the requirements of sequential decision policies as mixed-integer linear constraints. This is accomplished with user-specified dosage sequence tables, manipulation of one input at a time, and a switching time strategy for assigning dosages at time intervals less frequent than the measurement sampling interval. A model developed for a gestational weight gain (GWG) intervention is used to illustrate the generation of these sequential decision policies and their effectiveness for implementing adaptive behavioral interventions involving multiple components.

Dong, Yuwen; Deshpande, Sunil; Rivera, Daniel E.; Downs, Danielle S.; Savage, Jennifer S.

2015-01-01

431

Validation of coupled atmosphere-fire behavior models  

SciTech Connect

Recent advances in numerical modeling and computer power have made it feasible to simulate the dynamical interaction and feedback between the heat and turbulence induced by wildfires and the local atmospheric wind and temperature fields. At Los Alamos National Laboratory, the authors have developed a modeling system that includes this interaction by coupling a high resolution atmospheric dynamics model, HIGRAD, with a fire behavior model, BEHAVE, to predict the spread of wildfires. The HIGRAD/BEHAVE model is run at very high resolution to properly resolve the fire/atmosphere interaction. At present, these coupled wildfire model simulations are computationally intensive. The additional complexity of these models require sophisticated methods for assuring their reliability in real world applications. With this in mind, a substantial part of the research effort is directed at model validation. Several instrumented prescribed fires have been conducted with multi-agency support and participation from chaparral, marsh, and scrub environments in coastal areas of Florida and inland California. In this paper, the authors first describe the data required to initialize the components of the wildfire modeling system. Then they present results from one of the Florida fires, and discuss a strategy for further testing and improvement of coupled weather/wildfire models.

Bossert, J.E.; Reisner, J.M.; Linn, R.R.; Winterkamp, J.L. [Los Alamos National Lab., NM (United States); Schaub, R. [Dynamac Corp., Kennedy Space Center, FL (United States); Riggan, P.J. [Forest Service, Riverside, CA (United States)

1998-12-31

432

An integrative behavioral model of information security policy compliance.  

PubMed

The authors found the behavioral factors that influence the organization members' compliance with the information security policy in organizations on the basis of neutralization theory, Theory of planned behavior, and protection motivation theory. Depending on the theory of planned behavior, members' attitudes towards compliance, as well as normative belief and self-efficacy, were believed to determine the intention to comply with the information security policy. Neutralization theory, a prominent theory in criminology, could be expected to provide the explanation for information system security policy violations. Based on the protection motivation theory, it was inferred that the expected efficacy could have an impact on intentions of compliance. By the above logical reasoning, the integrative behavioral model and eight hypotheses could be derived. Data were collected by conducting a survey; 194 out of 207 questionnaires were available. The test of the causal model was conducted by PLS. The reliability, validity, and model fit were found to be statistically significant. The results of the hypotheses tests showed that seven of the eight hypotheses were acceptable. The theoretical implications of this study are as follows: (1) the study is expected to play a role of the baseline for future research about organization members' compliance with the information security policy, (2) the study attempted an interdisciplinary approach by combining psychology and information system security research, and (3) the study suggested concrete operational definitions of influencing factors for information security policy compliance through a comprehensive theoretical review. Also, the study has some practical implications. First, it can provide the guideline to support the successful execution of the strategic establishment for the implement of information system security policies in organizations. Second, it proves that the need of education and training programs suppressing members' neutralization intention to violate information security policy should be emphasized. PMID:24971373

Kim, Sang Hoon; Yang, Kyung Hoon; Park, Sunyoung

2014-01-01

433

The SEM Risk Behavior (SRB) Model: A New Conceptual Model of how Pornography Influences the Sexual Intentions and HIV Risk Behavior of MSM  

PubMed Central

While the effects of sexually explicit media (SEM) on heterosexuals’ sexual intentions and behaviors have been studied, little is known about the consumption and possible influence of SEM among men who have sex with men (MSM). Importantly, conceptual models of how Internet-based SEM influences behavior are lacking. Seventy-nine MSM participated in online focus groups about their SEM viewing preferences and sexual behavior. Twenty-three participants reported recent exposure to a new behavior via SEM. Whether participants modified their sexual intentions and/or engaged in the new behavior depended on three factors: arousal when imagining the behavior, pleasure when attempting the behavior, and trust between sex partners. Based on MSM’s experience, we advance a model of how viewing a new sexual behavior in SEM influences sexual intentions and behaviors. The model includes five paths. Three paths result in the maintenance of sexual intentions and behaviors. One path results in a modification of sexual intentions while maintaining previous sexual behaviors, and one path results in a modification of both sexual intentions and behaviors. With this model, researchers have a framework to test associations between SEM consumption and sexual intentions and behavior, and public health programs have a framework to conceptualize SEM-based HIV/STI prevention programs. PMID:23185126

Wilkerson, J. Michael; Iantaffi, Alex; Smolenski, Derek J.; Brady, Sonya S.; Horvath, Keith J.; Grey, Jeremy A.; Rosser, B. R. Simon

2012-01-01

434

Monopropellant hydrazine resistoject: Engineering model fabrication and test task  

NASA Technical Reports Server (NTRS)

The monopropellant hydrazine resistojet, termed the electrothermal hydrazine thruster (EHT) by TRW systems, thermally decomposes anhydrous hydrazine propellant to produce a high-temperature, low-molecular-weight gas for expulsion through a propulsive nozzle. The EHT developed for this program required about 3-5 watts of electrical power and produced 0.020 to 0.070 pound of thrust over the inlet pressure range of 100 to 400 psia. The thruster was designed for both pulsed and steady state operation. A summary of the GSFC original requirements and GSFC modified requirements, and the performance of the engineering model EHT is given. The experimental program leading to the engineering model EHT design, modifications necessary to achieve the required thruster life capability, and the results of the life test prgram. Other facets of the program, including analyses, preliminary design, specifications, data correlation, and recommendations for a flight model are discussed.

Murch, C. K.

1973-01-01

435

Mutation-based Model Synthesis in Model Driven Engineering McGill University (also at IRISA)  

E-print Network

Mutation-based Model Synthesis in Model Driven Engineering Sagar Sen McGill University (also of a sequence of model synthesis rules (or mutation operators) specified as Graph Grammar (GG) rules. These mutation operators are primitive GG rules , automatically obtained from any meta-model. Such plans can

Paris-Sud XI, Université de

436

The CCAILM Learning Model: An Instructional Model for Teaching and Learning of Engineering Modules  

ERIC Educational Resources Information Center

This research report presents a new teaching and learning model in engineering classes. The proposed learning model is called the CCAILM (constructionist computer aided instructional learning model). This new model was derived from the constructionist learning theory, the media-affects-learning hypothesis and the multiple representation principle.…

Faleye, Sunday

2011-01-01

437

Behavior of engineered nanoparticles in aqueous solutions and porous media: Connecting experimentation to probabilistic analysis  

NASA Astrophysics Data System (ADS)

Engineered nanoparticles have enhanced products and services in the fields of medicine, energy, engineering, communications, personal care, environmental treatment, and many others. The increased use of engineered nanoparticles in consumer products will lead to these materials in natural systems, inevitably becoming a potential source of pollution. The study of the stability and mobility of these materials is fundamental to understand their behavior in natural systems and predict possible health and environmental implications. In addition, the use of probabilistic methods such as sensitivity analysis applied to the parameters controlling their behavior is useful in providing support in performing a risk assessment. This research investigated the stability and mobility of two types of metal oxide nanoparticles (aluminum oxide and titanium dioxide). The stability studies tested the effect of sand, pH 4, 7, and 10, and the NaCl in concentrations of 10mM, 25mM, 50mM, and 75mM. The mobility was tested using saturated quartz sand columns and nanoparticles suspension at pH 4 and 7 and in the presence of NaCl and CaCl2 in concentrations of 0.1mM, 1mM, and 10mM. Additionally, this work performed a sensitivity analysis of physical parameters used in mobility experiment performed for titanium dioxide and in mobility experiments taken from the literature for zero valent iron nanoparticles and fluorescent colloids to determine their effect on the value C/Co of by applying qualitative and quantitative methods. The results from the stability studies showed that titanium dioxide nanoparticles (TiO2) could remain suspended in solution for up to seven days at pH 10 and pH 7 even after settling of the sand; while for pH 4 solutions titanium settled along with the sand and after seven days no particles were observed in suspension. Other stability studies showed that nanoparticle aluminum oxide (Al2O3) and titanium dioxide (TiO2) size increased with increasing ionic strength (10 to 75 mM NaCl). The results from the mobility experiments showed that ionic strength has more effect on aluminum oxide nanoparticles mobility than on titanium oxide nanoparticles mobility. For Al2O3 25% of the initial concentration was obtained in the effluent whereas for TiO2 less than the 10% of the initial concentration was observed. In general, when the ionic strength was increased the effluent of nanoparticles decreased. Collision efficiencies calculated base on the colloid filtration theory were consistent with the mobility experiments. Results from sensitivity analysis showed that for zero valent iron nanoparticles and fluorescent colloids porous medium diameter and porosity were the parameters that most influenced the variability of C/Co whereas for titanium dioxide nanoparticles C/Co was more sensitive to column length and pore water velocity.

Contreras, Carolina

2011-12-01

438

76 FR 25648 - Special Conditions: Gulfstream Model GVI Airplane; Limit Engine Torque Loads for Sudden Engine...  

Federal Register 2010, 2011, 2012, 2013

...361(b)(1) requires that for turbine engine installations, the engine mounts and the supporting structures must be...special conditions are proposed: 1. For turbine engine installations, the engine mounts, pylons and adjacent...

2011-05-05

439

Interactive training model of TRIZ for mechanical engineers in China  

NASA Astrophysics Data System (ADS)

Innovation is a process of taking an original idea and converting it into a business value, in which the engineers face some inventive problems which can be solved hardly by experience. TRIZ, as a new theory for companies in China, provides both conceptual and procedural knowledge for finding and solving inventive problems. Because the government plays a leading role in the diffusion of TRIZ, too many companies from different industries are waiting to be trained, but the quantity of the trainers mastering TRIZ is incompatible with that requirement. In this context, to improve the training effect, an interactive training model of TRIZ for the mechanical engineers in China is developed and the implementation in the form of training classes is carried out. The training process is divided into 6 phases as follows: selecting engineers, training stage-1, finding problems, training stage-2, finding solutions and summing up. The government, TRIZ institutions and companies to join the programs interact during the process. The government initiates and monitors a project in form of a training class of TRIZ and selects companies to join the programs. Each selected companies choose a few engineers to join the class and supervises the training result. The TRIZ institutions design the training courses and carry out training curriculum. With the beginning of the class, an effective communication channel is established by means of interview, discussion face to face, E-mail, QQ and so on. After two years training practices, the results show that innovative abilities of the engineers to join and pass the final examinations increased distinctly, and most of companies joined the training class have taken congnizance of the power of TRIZ for product innovation. This research proposes an interactive training model of TRIZ for mechanical engineers in China to expedite the knowledge diffusion of TRIZ.

Tan, Runhua; Zhang, Huangao

2014-03-01

440

Modeling of Cardiac Muscle Thin Films: Pre-stretch, Passive and Active Behavior  

PubMed Central

Recent progress in tissue engineering has made it possible to build contractile bio-hybrid materials that undergo conformational changes by growing a layer of cardiac muscle on elastic polymeric membranes. Further development of such muscular thin films for building actuators and powering devices requires exploring several design parameters, which include the alignment of the cardiac myocytes and the thickness/Young’s modulus of elastomeric film. To more efficiently explore these design parameters, we propose a 3-D phenomenological constitutive model, which accounts for both the passive deformation including pre-stretch and the active behavior of the cardiomyocytes. The proposed 3-D constitutive model is implemented within a finite element framework, and can be used to improve the current design of bio-hybrid thin films and help developing bio-hybrid constructs capable of complex conformational changes. PMID:22236531

Shim, Jongmin; Grosberg, Anna; Nawroth, Janna C.; Parker, Kevin Kit; Bertoldi, Katia

2012-01-01

441

Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model  

NASA Technical Reports Server (NTRS)

This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

Connolly, Joseph W.; Friedlander, David; Kopasakis, George

2014-01-01

442

Modeling longitudinal driving behaviors at defective sites on urban expressways  

NASA Astrophysics Data System (ADS)

Understanding the psychological impacts of defect sites on drivers, and the resulting driving behaviors are crucial to the accident management and traffic safety improvement. This paper presents a new traffic flow model based on the two-lane cellular automaton model. In a model where a finite number of particles (e.g. vehicles) or sites (e.g. traffic incident sites) have different properties from the rest these are usually called defects. The defective site's impact is introduced, bringing the changes of acceleration, deceleration, random deceleration and headway. At the defect site, the vehicles decelerate spontaneously. The greater the impact is, the larger deceleration probability will be. Simulations of the proposed model and the classic NaSch model are given. The results suggest the remaining capacity of the proposed model is approximately 54.6% of that of NaSch model. Compared to empirical data, the model can describe the traffic flow at defect site better than NaSch model.

Yang, Xiaofang; Wang, Xinzhu; Fu, Qiang; Cheng, Yang; Ran, Bin

2014-09-01

443

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

PubMed

In order to describe the dynamic behavior of a complex biological system, it is useful to combine models integrating processes at different levels and with temporal dependencies. Such combinations are necessary for modeling acclimatization, a phenomenon where changes in environmental conditions can induce drastic changes in the behavior of a biological system. In this article we formalize the use of hybrid systems as a tool to model this kind of biological behavior. A modeling scheme called strong switches is proposed. It allows one to take into account both minor adjustments to the coefficients of a continuous model, and, more interestingly, large-scale changes to the structure of the model. We illustrate the proposed methodology with two applications: acclimatization in wine fermentation kinetics, and acclimatization of osteo-adipo differentiation system linking stimulus signals to bone mass. PMID:24892552

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

2014-07-01

444

Advances in engineering turbulence modeling. [computational fluid dynamics  

NASA Technical Reports Server (NTRS)

Some new developments in two equation models and second order closure models are presented. In this paper, modified two equation models are proposed to remove shortcomings such as computing flows over complex geometries and the ad hoc treatment near the separation and reattachment points. The calculations using various two equation models are compared with direct numerical solutions of channel flows and flat plate boundary layers. Development of second order closure models will also be discussed with emphasis on the modeling of pressure related correlation terms and dissipation rates in the second moment equations. All existing models poorly predict the normal stresses near the wall and fail to predict the three dimensional effect of mean flow on the turbulence. The newly developed second order near-wall turbulence model to be described in this paper is capable of capturing the near-wall behavior of turbulence as well as the effect of three dimension mean flow on the turbulence.

Shih, T.-H.

1992-01-01

445

Fish behavior in relation to modeling fish passage through hydropower turbines: A review  

SciTech Connect

We evaluated the literature on fish behavior as it relates to passage of fish near or through hydropower turbines. The goal was to foster compatibility of engineered systems with the normal behavior patterns of fish species and life stages such that entrainment into turbines and injury in passage are minimized. We focused on aspects of fish behavior that could be used for computational fluid dynamics (CFD) modeling of fish trajectories through turbine systems. Downstream-migrating salmon smolts are generally surface oriented and follow flow. Smolts orient to the ceilings of turbine intakes but are horizontally distributed more evenly, except as affected by intake-specific turbulence and vortices. Smolts often enter intakes oriented head-upstream. Non-salmonids are entrained episodically, suggesting accidental capture of schools (often of juveniles or in cold water) and little behavioral control during turbine passage. Models of fish trajectories should not assume neutral buoyancy throughout the time a fish passes through a turbine, largely because of pressure effects on swim bladders. Fish use their lateral line system to sense obstacles and change their orientation, but this sensory-response system may not be effective in the rapid passage times of turbine systems. A Effects of pre-existing stress levels on fish performance in turbine passage are not well known but may be important. There are practical limits of observation and measurement of fish and flows in the proximity of turbine runners that may inhibit development of information germane to developing a more fish-friendly turbine. We provide recommendations for CFD modelers of fish passage and for additional research. 20 refs., 2 figs.

Coutant, C.C. [Oak Ridge National Lab., TN (United States); Whitney, R.R.

1997-06-01

446

Monitoring and modeling the soil hydraulic behavior in stony soils  

NASA Astrophysics Data System (ADS)

Describing the soil hydrological behavior at applicative scales remains a complex task, mainly because of the spatial heterogeneity of the vadose zone. Addressing the impact of the unsaturated zone heterogeneity involves measuring and/or modeling water content evolution with fine spatial and temporal resolution. The presence of stones introduces difficulties for both the measurement of the water content and the soil hydraulic properties. In this context, the main objective of this study was to assess the role of stones on TDR-based water content measurements, as well as on the pattern of variability of simulated water contents at field-scale during water infiltration, drainage and evaporation processes. Also, the role of stones was evaluated as one possible explanation of the differences frequently observed between the measured hydraulic behavior and that estimated by using pedotransfer functions.

Dragonetti, Giovanna; Lamaddalena, Nicola; Comegna, Alessandro; Coppola, Antonio

2014-05-01

447

Modeling the behavior of DNA-loop-extruding enzymes  

NASA Astrophysics Data System (ADS)

Condensin proteins are large complexes belonging to a family of ATP hydrolyzing proteins known as SMC (Structural Maintenance of Chromosomes). Condensins are believed to play a vital role in chromosomal assembly and segregation in eukaryotic cells but the details of their function along chromatin are poorly understood. Here, we propose a model to describe the behavior of DNA-loop-inducing proteins, such as type I restriction enzymes, which we believe can be used to understand condensin's function. We assume an effective motor behavior for these enzymes in which the bias of the two dimer heads is to travel away from each other, which results in loop formation along the DNA lattice. Processivity causes the enzymes to stack on top of each other. We further discuss the results of theory and computer simulations for different values of motor bias and processivity.

Baum-Snow, Elnaz A.; Marko, John F.

2009-03-01

448

Current Progress of Genetically Engineered Pig Models for Biomedical Research  

PubMed Central

Abstract The first transgenic pigs were generated for agricultural purposes about three decades ago. Since then, the micromanipulation techniques of pig oocytes and embryos expanded from pronuclear injection of foreign DNA to somatic cell nuclear transfer, intracytoplasmic sperm injection-mediated gene transfer, lentiviral transduction, and cytoplasmic injection. Mechanistically, the passive transgenesis approach based on random integration of foreign DNA was developed to active genetic engineering techniques based on the transient activity of ectopic enzymes, such as transposases, recombinases, and programmable nucleases. Whole-genome sequencing and annotation of advanced genome maps of the pig complemented these developments. The full implementation of these tools promises to immensely increase the efficiency and, in parallel, to reduce the costs for the generation of genetically engineered pigs. Today, the major application of genetically engineered pigs is found in the field of biomedical disease modeling. It is anticipated that genetically engineered pigs will increasingly be used in biomedical research, since this model shows several similarities to humans with regard to physiology, metabolism, genome organization, pathology, and aging. PMID:25469311

Gün, Gökhan

2014-01-01

449

Engineering-Level Model Atmospheres for Titan & Neptune  

NASA Technical Reports Server (NTRS)

Engineering-level atmospheric models for Titan and Neptune have been developed for use in NASA s systems analysis studies of aerocapture applications in missions to the outer planets. Analogous to highly successful Global Reference Atmospheric Models for Earth (GRAM, Justus et al., 2000) and Mars (Mars-GRAM, Justus and Johnson, 2001, Justus et al., 2002) the new models are called Titan-GRAM and Neptune-GRAM. Like GRAM and Mars-GRAM, an important feature of Titan-GRAM and Neptune-GRAM is their ability to simulate quasi-random perturbations for Monte- Carlo analyses in developing guidance, navigation and control algorithms, and for thermal systems design.

Justus, C. G.; Johnson, D. L.

2003-01-01

450

An Integrated Model of Waste Management BehaviorA Test of Household Recycling and Composting Intentions  

Microsoft Academic Search

This study examines the antecedents of recycling and composting intentions in the context of an integrated waste management behavior model. This model incorporates a wide variety of important factors from previous research on environmental behavior. The theory of planned behavior provides a theoretical framework to integrate these factors. The model was tested using both recycling and composting data from a

Shirley Taylor; Peter Todd

1995-01-01

451

Socialized Gaussian Process Model for Human Behavior Prediction in a Health Social Network  

E-print Network

Socialized Gaussian Process Model for Human Behavior Prediction in a Health Social Network Yelong behavior in a social network. In this work, we propose a Socialized Gaussian Process (SGP) for socialized behavior factor and social correlation factor into a unified model, where basic Gaussian Process model

Dou, Dejing

452

Accepted Manuscript Experimental Study and Modeling of Single Yarn Pull-out Behavior of Kevlar  

E-print Network

Accepted Manuscript Experimental Study and Modeling of Single Yarn Pull-out Behavior of Kevlar ® 49., Mobasher, B., Rajan, S.D., Experimental Study and Modeling of Single Yarn Pull-out Behavior of Kevlar ® 49 to the journal pertain. #12;Experimental Study and Modeling of Single Yarn Pull-out Behavior of Kevlar® 49 Fabric

Mobasher, Barzin

453

A Model of Knower-Level Behavior in Number Concept Development  

E-print Network

-level theory of how children repre- sent numbers. To produce behavior on the Give-N task, the model assumesA Model of Knower-Level Behavior in Number Concept Development Michael D. Lee, Barbara W. Sarnecka in revised from 2 March 2009; accepted 9 June 2009 Abstract We develop and evaluate a model of behavior

Stanford, Kyle

454

Model-driven engineering of gene expression from RNA replicons.  

PubMed

RNA replicons are an emerging platform for engineering synthetic biological systems. Replicons self-amplify, can provide persistent high-level expression of proteins even from a small initial dose, and, unlike DNA vectors, pose minimal risk of chromosomal integration. However, no quantitative model sufficient for engineering levels of protein expression from such replicon systems currently exists. Here, we aim to enable the engineering of multigene expression from more than one species of replicon by creating a computational model based on our experimental observations of the expression dynamics in single- and multireplicon systems. To this end, we studied fluorescent protein expression in baby hamster kidney (BHK-21) cells using a replicon derived from Sindbis virus (SINV). We characterized expression dynamics for this platform based on the dose-response of a single species of replicon over 50 h and on a titration of two cotransfected replicons expressing different fluorescent proteins. From this data, we derive a quantitative model of multireplicon expression and validate it by designing a variety of three-replicon systems, with profiles that match desired expression levels. We achieved a mean error of 1.7-fold on a 1000-fold range, thus demonstrating how our model can be applied to precisely control expression levels of each Sindbis replicon species in a system. PMID:24877739

Beal, Jacob; Wagner, Tyler E; Kitada, Tasuku; Azizgolshani, Odisse; Parker, Jordan Moberg; Densmore, Douglas; Weiss, Ron

2015-01-16

455

Numerical Modeling of Drying Residual RP-1 in Rocket Engines  

NASA Technical Reports Server (NTRS)

When a Rocket Engine shuts down under a fuel rich environment, a significant amount of unburned RP-1 is trapped In the engine. It is necessary to clean the residual RP-1 prior to subsequent firing to avoid any explosion due to detonation. The conventional method is to dry RP-1 with inert gas such as Nitrogen or Helium. It is difficult to estimate the drying time unless the engine is adequately equipped with instruments to measure the trace of RP-1 during the drying process. Such instrumentation in flight hardware is often impractical and costly. On the other hand numerical modeling of the drying process can provide a good insight for a satisfactory operation of the process. A numerical model can provide answer to questions such as a) how long it takes to dry, b) which fluid is a better dryer for RP-1, c) how to reduce drying time etc. The purpose of the present paper is to describe a numerical model of drying RP-1 trapped in a cavity with flowing nitrogen or helium. The numerical model assumes one dimensional flow of drying fluid in contact with liquid pool of RP-1. An evaporative mass transfer takes place across the contact surface.

Majumdar, Alok; Polsgrove, Robert; Tiller, Bruce; Rodriquez, Pete (Technical Monitor)

2000-01-01

456

A cognitive-behavioral model of Internet gaming disorder: theoretical underpinnings and clinical implications.  

PubMed

Cognitive contributions to the behaviors observed in substance and non-substance addictions have been investigated and characterized. Based on models of drug addictions and the extant literature on Internet gaming disorder (IGD), we propose a cognitive-behavioral model for conceptualizing IGD. The model focuses on three domains and their roles in addictive behaviors. The three domains include motivational drives related to reward-seeking and stress-reduction, behavioral control relating to executive inhibition, and decision-making that involves weighing the pros and cons of engaging in motivated behaviors. Based on this model, we propose how behavioral therapies might target these domains in the treatment of IGD. PMID:25062755

Dong, Guangheng; Potenza, Marc N

2014-11-01

457

The New NASA Orbital Debris Engineering Model ORDEM2000  

NASA Technical Reports Server (NTRS)

The NASA Orbital Debris Program Office at Johnson Space Center has developed a new computer-based orbital debris engineering model, ORDEM2000, which describes the orbital debris environment in the low Earth orbit region between 200 and 2000 km altitude. The model is appropriate for those engineering solutions requiring knowledge and estimates of the orbital debris environment (debris spatial density, flux, etc.). ORDEM2000 can also be used as a benchmark for ground-based debris measurements and observations. We incorporated a large set of observational data, covering the object size range from 10 mm to 10 m, into the ORDEM2000 debris database, utilizing a maximum likelihood estimator to convert observations into debris population probability distribution functions. These functions then form the basis of debris populations. We developed a finite element model to process the debris populations to form the debris environment. A more capable input and output structure and a user-friendly graphical user interface are also implemented in the model. ORDEM2000 has been subjected to a significant verification and validation effort. This document describes ORDEM2000, which supersedes the previous model, ORDEM96. The availability of new sensor and in situ data, as well as new analytical techniques, has enabled the construction of this new model. Section 1 describes the general requirements and scope of an engineering model. Data analyses and the theoretical formulation of the model are described in Sections 2 and 3. Section 4 describes the verification and validation effort and the sensitivity and uncertainty analyses. Finally, Section 5 describes the graphical user interface, software installation, and test cases for the user.

Liou, Jer-Chyi; Matney, Mark J.; Anz-Meador, Phillip D.; Kessler, Donald; Jansen, Mark; Theall, Jeffery R.

2002-01-01

458

Aspect-Oriented Model-Driven Software Product Line Engineering  

NASA Astrophysics Data System (ADS)

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

Groher, Iris; Voelter, Markus

459

A catastrophe-theory model for simulating behavioral accidents  

SciTech Connect

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

Souder, W.E.

1988-01-01

460

LATER models of neural decision behavior in choice tasks  

PubMed Central

Reaction time has been increasingly used over the last few decades to provide information on neural decision processes: it is a direct reflection of decision time. Saccades provide an excellent paradigm for this because many of them can be made in a very short time and the underlying neural pathways are relatively well-known. LATER (linear approach to threshold with ergodic rate) is a model originally devised to explain reaction time distributions in simple decision tasks. Recently, however it is being extended to increasingly more advanced tasks, including those with decision errors and those requiring voluntary control such as the antisaccade task and those where sequential decisions are required. The strength of this modeling approach lies in its detailed, quantitative predictions of behavior, yet LATER models still retain their conceptual simplicity that made LATER initially successful in explaining reaction times in simple decision tasks. PMID:25202242

Noorani, Imran

2014-01-01

461

Bio-CAD modeling and its applications in computer-aided tissue engineering  

E-print Network

Bio-CAD modeling and its applications in computer-aided tissue engineering W. Sun*, B. Starly, J biomedical applications, particularly tissue engineering in which CAD based bio-tissue informatics model of bio-CAD modeling and application in computer-aided tissue engineering, including biomimetic design

Sun, Wei

462

Torsional vibration analysis of a multi-body single cylinder internal combustion engine model  

Microsoft Academic Search

This paper presents a detailed multi-body numerical nonlinear dynamic model of a single cylinder internal combustion engine. The model comprises all rigid body inertial members, support bearings, joints, couplers, and connections between the various engine components, as well as means of vibration damping. The detailed model is parameterised, thus enabling virtual prototype testing of various engine designs, as well as

A. Boysal; H. Rahnejat

1997-01-01

463

A Process Engineering Method based on a Process Domain Model and Patterns  

E-print Network

A Process Engineering Method based on a Process Domain Model and Patterns Charlotte Hug, Agnès to build unified, fitted and multi-viewpoints process meta-models. The process engineering method is based engineering, method. 1 Introduction There are many different process meta-models and each of them represents

Boyer, Edmond

464

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

Microsoft Academic Search

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

1992-01-01

465

Mechanical behavior in living cells consistent with the tensegrity model.  

PubMed

Alternative models of cell mechanics depict the living cell as a simple mechanical continuum, porous filament gel, tensed cortical membrane, or tensegrity network that maintains a stabilizing prestress through incorporation of discrete structural elements that bear compression. Real-time microscopic analysis of cells containing GFP-labeled microtubules and associated mitochondria revealed that living cells behave like discrete structures composed of an interconnected network of actin microfilaments and microtubules when mechanical stresses are applied to cell surface integrin receptors. Quantitation of cell tractional forces and cellular prestress by using traction force microscopy confirmed that microtubules bear compression and are responsible for a significant portion of the cytoskeletal prestress that determines cell shape stability under conditions in which myosin light chain phosphorylation and intracellular calcium remained unchanged. Quantitative measurements of both static and dynamic mechanical behaviors in cells also were consistent with specific a priori predictions of the tensegrity model. These findings suggest that tensegrity represents a unified model of cell mechanics that may help to explain how mechanical behaviors emerge through collective interactions among different cytoskeletal filaments and extracellular adhesions in living cells. PMID:11438729

Wang, N; Naruse, K; Stamenovi?, D; Fredberg, J J; Mijailovich, S M; Toli?-Nørrelykke, I M; Polte, T; Mannix, R; Ingber, D E

2001-07-01

466

Mechanical behavior in living cells consistent with the tensegrity model  

NASA Technical Reports Server (NTRS)

Alternative models of cell mechanics depict the living cell as a simple mechanical continuum, porous filament gel, tensed cortical membrane, or tensegrity network that maintains a stabilizing prestress through incorporation of discrete structural elements that bear compression. Real-time microscopic analysis of cells containing GFP-labeled microtubules and associated mitochondria revealed that living cells behave like discrete structures composed of an interconnected network of actin microfilaments and microtubules when mechanical stresses are applied to cell surface integrin receptors. Quantitation of cell tractional forces and cellular prestress by using traction force microscopy confirmed that microtubules bear compression and are responsible for a significant portion of the cytoskeletal prestress that determines cell shape stability under conditions in which myosin light chain phosphorylation and intracellular calcium remained unchanged. Quantitative measurements of both static and dynamic mechanical behaviors in cells also were consistent with specific a priori predictions of the tensegrity model. These findings suggest that tensegrity represents a unified model of cell mechanics that may help to explain how mechanical behaviors emerge through collective interactions among different cytoskeletal filaments and extracellular adhesions in living cells.

Wang, N.; Naruse, K.; Stamenovic, D.; Fredberg, J. J.; Mijailovich, S. M.; Tolic-Norrelykke, I. M.; Polte, T.; Mannix, R.; Ingber, D. E.

2001-01-01

467

Failure behavior and constitutive model of weakly consolidated soft rock.  

PubMed

Mining areas in western China are mainly located in soft rock strata with poor bearing capacity. In order to make the deformation failure mechanism and strength behavior of weakly consolidated soft mudstone and coal rock hosted in Ili No. 4 mine of Xinjiang area clear, some uniaxial and triaxial compression tests were carried out according to the samples of rocks gathered in the studied area, respectively. Meanwhile, a damage constitutive model which considered the initial damage was established by introducing a damage variable and a correction coefficient. A linearization process method was introd