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1

Behavior modeling in mechanical engineering — A modular approach  

Microsoft Academic Search

Many engineering activities are confronted with the relation between shape and behavior. Modern ‘state-of-the-art’ CAD systems can support a dynamic design process with flexible and umambiguous geometric modeling of artifacts. The Finite Element (FE) method is a general method to model and simulate physical behavior. CAD and FE integration enables numerical prediction of the physical behavior of artifacts. To deal

Ulf Sellgren; Raphafil Drogou

1998-01-01

2

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

3

Deployment Mechanism Design with Behavioral Modeling Based on Pro/Engineer Motion Skeleton  

E-print Network

Deployment Mechanism Design with Behavioral Modeling Based on Pro/Engineer Motion Skeleton Chao.com.cn Keywords: Deployment mechanism, Motion skeleton, Behavioral modeling, Feasibility analysis Abstract. A novel method using motion skeleton and behavioral modeling in Pro/Engineer to design a motion mechanism

4

3D behavioral model design for simulation and software engineering  

Microsoft Academic Search

Modeling is used to build structures that serve as surrogates for other objects. As children, we learn to model at a very young age. An object such as a small toy train teaches us about the structure and behavior of an actual train. VRML is a file standard for representing the structure of objects such as trains, while the behavior

Paul A. Fishwick

2000-01-01

5

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

6

Health Behaviors of Operating Engineers  

PubMed Central

RESEARCH ABSTRACT Operating Engineers (heavy equipment operators in construction) may be at particular risk for heart disease and cancer related to their exposure to environmental dust and smoking, the sedentary nature of their job, and long hours of exposure to the sun. The aim of this study was to characterize the health behaviors of Operating Engineers. This cross-sectional survey from a convenience sample of Operating Engineers (N = 498) used validated instruments to measure smoking, drinking, diet, exercise, sleep, and sun exposure. Univariate and bivariate analyses to detect differences by age were conducted. The sample scored significantly worse on all five health behaviors compared to population norms. Those who were older were less likely to smoke and chew tobacco and more likely to eat fruits and vegetables. Many were interested in services to improve their health behaviors. Health behavior interventions are needed and wanted by Operating Engineers. PMID:21688764

Duffy, Sonia A.; Missel, Amanda L.; Waltje, Andrea H.; Ronis, David L.; Fowler, Karen E.; Hong, OiSaeng

2013-01-01

7

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

USGS Publications Warehouse

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

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

2000-01-01

8

Behaviorally Engineered Environments. Staff Papers.  

ERIC Educational Resources Information Center

This collection of papers represents the developmental research as well as the thrust of the Regional Laboratory's (UMREL) program. UMREL has been developing behaviorally engineered educational environments through a cross-disciplinary effort in education and the behavioral sciences. The program began with the establishment of demonstration…

Morreau, Larry E.; And Others

9

Model Behavior  

ERIC Educational Resources Information Center

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

Holloway, John

2006-01-01

10

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

11

Abnormal Behavior in a Chromosome- Engineered Mouse Model for Human 15q11-13 Duplication Seen in Autism  

PubMed Central

Summary Substantial evidence suggests that chromosomal abnormalities contribute to the risk of autism. The duplication of human chromosome 15q11-13 is known to be the most frequent cytogenetic abnormality in autism. We have modeled this genetic change in mice by using chromosome engineering to generate a 6.3 Mb duplication of the conserved linkage group on mouse chromosome 7. Mice with a paternal duplication display poor social interaction, behavioral inflexibility, abnormal ultrasonic vocalizations, and correlates of anxiety. An increased MBII52 snoRNA within the duplicated region, affecting the serotonin 2c receptor (5-HT2cR), correlates with altered intracellular Ca2+ responses elicited by a 5-HT2cR agonist in neurons of mice with a paternal duplication. This chromosome-engineered mouse model for autism seems to replicate various aspects of human autistic phenotypes and validates the relevance of the human chromosome abnormality. This model will facilitate forward genetics of developmental brain disorders and serve as an invaluable tool for therapeutic development. PMID:19563756

Nakatani, Jin; Tamada, Kota; Hatanaka, Fumiyuki; Ise, Satoko; Ohta, Hisashi; Inoue, Kiyoshi; Tomonaga, Shozo; Watanabe, Yasuhito; Chung, Yeun Jun; Banerjee, Ruby; Iwamoto, Kazuya; Kato, Tadafumi; Okazawa, Makoto; Yamauchi, Kenta; Tanda, Koichi; Takao, Keizo; Miyakawa, Tsuyoshi; Bradley, Allan; Takumi, Toru

2009-01-01

12

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

E-print Network

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

Xu, Dian

2010-01-01

13

Model Behavior.  

ERIC Educational Resources Information Center

Statistical modeling provides a method for colleges to use alumni-development information to create an equation predicting who is likely to respond positively to fund-raising appeals. This can make fund raising more cost-effective, provide higher returns on minimal investment, provide results quickly, and improve competitiveness. Resources…

Wylie, Peter B.

1999-01-01

14

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

15

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

Microsoft Academic Search

Social cognitive career theory (SCCT; R. W. Lent, S. D. Brown, & 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 course) completed measures of SCCT's person (self-efficacy, coping efficacy, outcome

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

2003-01-01

16

Behavior Modeling for Results.  

ERIC Educational Resources Information Center

Discusses the benefits of behavior modeling, examines the Behavior Modeling Learning Staircase (which illustrates the situational and generic skills that can be developed in a supervisory training program), and describes the role of the trainer. (CT)

Hultman, Kenneth E.

1986-01-01

17

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

18

ALSEP ENGINEERING MODEL TESTS  

E-print Network

CAT H3 CAT H4 ARRAY ''A-3'' ARRAY 11 811 CAT HI CAT #2 CAT f3&4 OCT NOV DEC JAN FEB MAR APR MAYNASA S-67-27433 ALSEP ENGINEERING MODEL TESTS Aerospace Syste111s Division 4422 EXPERIMENT~- ----· DATA SIMULATORS-- .. DATA ... -- -.,. SUBSYSTEM SUBSYSTEM ---TEST SET 4422-2302 #12;NASA S

Rathbun, Julie A.

19

The behavioral science contribution to emergency management and engineering  

SciTech Connect

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

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

1995-12-31

20

Engineering technology and behavior analysis for interdisciplinary environmental protection  

PubMed Central

Engineering strategies for saving environmental resources have been widespread. However, many of those engineering advances have not been widely accepted nor generally applied by large segments of the general population. This paper considers the need to examine behavioral/environmental variables in the application of engineering technology, with particular reference to specific behavioral strategies for encouraging the use of engineering technology from an interdisciplinary perspective. A model for the study of factors contributing to the solution of ecological/environmental problems is presented and examples of interdisciplinary research are described. The model implies a need for the examination of the effects of antecedent and consequent manipulation of a variety of variables including: behavioral, physiological, environmental, technical and legal conditions. It is concluded that while interdisciplinary research efforts between engineering technologists and behavioral analysts are necessary, they have not received sufficient attention in the literature nor have they focused on the comprehensive study of antecedents and consequences as they relate to ecological/environmental problems. Thus, an extended “family” of research efforts is important for the success of these efforts. PMID:22478473

Johnson, Richard P.; Geller, E. Scott

1980-01-01

21

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

22

Advancements in engineering turbulence modeling  

NASA Technical Reports Server (NTRS)

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

Shih, T.-H.

1991-01-01

23

MODEL OF TOXICANT RESPONSE IN ENGINEERED LIVER  

EPA Science Inventory

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

24

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

25

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

2011-01-20

26

2010 Travel Behavior Inventory: Model Development  

E-print Network

Conference #12;2 · Regional planning · Emissions estimates · Project development ­ Engineering ­ Project2010 Travel Behavior Inventory: Model Development CTS 25th Annual Transportation Research benefits ­ Environmental impacts Forecast Models #12;3 · Non-home based trips · Lack of policy sensitivity

Minnesota, University of

27

Efficient Model-Based Diagnosis Engine  

NASA Technical Reports Server (NTRS)

An efficient diagnosis engine - a combination of mathematical models and algorithms - has been developed for identifying faulty components in a possibly complex engineering system. This model-based diagnosis engine embodies a twofold approach to reducing, relative to prior model-based diagnosis engines, the amount of computation needed to perform a thorough, accurate diagnosis. The first part of the approach involves a reconstruction of the general diagnostic engine to reduce the complexity of the mathematical-model calculations and of the software needed to perform them. The second part of the approach involves algorithms for computing a minimal diagnosis (the term "minimal diagnosis" is defined below). A somewhat lengthy background discussion is prerequisite to a meaningful summary of the innovative aspects of the present efficient model-based diagnosis engine. In model-based diagnosis, the function of each component and the relationships among all the components of the engineering system to be diagnosed are represented as a logical system denoted the system description (SD). Hence, the expected normal behavior of the engineering system is the set of logical consequences of the SD. Faulty components lead to inconsistencies between the observed behaviors of the system and the SD (see figure). Diagnosis - the task of finding faulty components - is reduced to finding those components, the abnormalities of which could explain all the inconsistencies. The solution of the diagnosis problem should be a minimal diagnosis, which is a minimal set of faulty components. A minimal diagnosis stands in contradistinction to the trivial solution, in which all components are deemed to be faulty, and which, therefore, always explains all inconsistencies.

Fijany, Amir; Vatan, Farrokh; Barrett, Anthony; James, Mark; Mackey, Ryan; Williams, Colin

2009-01-01

28

Responsibility-Driven Explanation Engineering for Cognitive Models  

E-print Network

model behaviors within aspects. Soar is used an example cognitive architecture, but the methodsResponsibility-Driven Explanation Engineering for Cognitive Models Steven R. Haynes, Isaac G for developing explanation facilities for cognitive architectures based on techniques drawn from object

Ritter, Frank

29

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

30

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

31

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

32

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

33

Atmospheric Models for Engineering Applications  

NASA Technical Reports Server (NTRS)

This paper will review the historical development of reference and standard atmosphere models and their applications. The evolution of the U.S. Standard Atmosphere will be addressed, along with the Range Reference Atmospheres and, in particular, the NASA Global Reference Atmospheric Model (GRAM). The extensive scope and content of the GRAM will be addressed since it represents the most extensive and complete 'Reference' atmosphere model in use today. Its origin was for engineering applications and that remains today as its principal use.

Johnson, Dale L.; Roberts, Barry C.; Vaughan, William W.; Justus, C. G.

2002-01-01

34

Stirling Engine Dynamic System Modeling  

NASA Technical Reports Server (NTRS)

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

Nakis, Christopher G.

2004-01-01

35

Modeling Network Forensics Behavior  

Microsoft Academic Search

Network forensics is a new approach to network security. However, this field is not very clear to new researchers and practitioners. In this paper, we discuss network forensics behavior systematically from both the technical view and legal view. The goal of this discussion is to outline the formalization and standardization of network forensics behavior. To our knowledge, this is the

Wei Ren

2006-01-01

36

Modeling Engineering Systems with Geometry  

Microsoft Academic Search

The theory of connection has been used to solve many problems in engineering. economics, and in management; in this paper, firstly, the theory of connection is introduced. Secondly, a new toolbox of functions for modeling and simulation is presented. Thirdly, the theory is used to solve a planning and scheduling problem with the help of the toolbox of functions. The

Reggie Davidrajuh

2009-01-01

37

An Object Model for a Rocket Engine Numerical Simulator  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

38

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

39

Information Technology Ethical Behavior: Toward a Comprehensive Ethical Behavior Model  

Microsoft Academic Search

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

Timothy Paul Cronan; David E. Douglas

40

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

41

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

42

Noise exposure levels from model airplane engines.  

PubMed

Previous research indicates that noise levels from unmuffled model airplane engines produce sufficient noise to cause TTS. The present study explored SPLs of smaller engines under 3.25 cc (.19 cu. in.) and the effectiveness of engine mufflers. Results showed that model airplanes can exceed a widely used damage risk criterion (DRC) but that engine mufflers can reduce levels below DRC. Handling model gasoline engines should be added to the list of recreational activities such as snow-mobile and motorcycle riding, shooting, etc. in which the participant's hearing may be in jeopardy. Suggestions are presented to the model engine enthusiast for avoiding damage to hearing. PMID:3836992

Pearlman, R C; Miller, M

1985-01-01

43

Nonparametric Bayesian behavior modeling  

E-print Network

As autonomous robots are increasingly used in complex, dynamic environments, it is crucial that the dynamic elements are modeled accurately. However, it is often difficult to generate good models due to either a lack of ...

Joseph, Joshua Mason

2008-01-01

44

Behavioral model simulation studies of an image compressor. Thesis  

NASA Technical Reports Server (NTRS)

The high initial cost of prototype Very Large Scaled Integrated (VLSI) parts requires that sufficient verifications be made to eliminate design errors before actually producing the prototypes. Logic simulation is the means by which the VLSI engineer can ensure that the design will function properly. The computer time required for logic simulation can be reduced through the use of behavioral models. Behavioral models, however, require time to write and verify and they do not always produce a dramatic speed up in logic simulation time. This paper presents a study of behavioral modeling aimed at discovering which circuit types benefit most from the use of behavioral models for logic simulation.

Madani, Navid; Whitaker, Sterling

1993-01-01

45

Responsibility-Driven Explanation Engineering for Cognitive Models  

Microsoft Academic Search

We describe an approach for developing explanation facilities for cognitive architectures based on techniques drawn from object- and aspect-oriented software engineering. We examine the use of responsibility-driven design augmented with scenario-based techniques and class- responsibility-collaboration (CRC) cards to identify explanation behaviors for cognitive model elements, and discuss the explanation benefits derived from encapsulating model behaviors within aspects. Soar is used

Steven R. Haynes; Isaac G. Councill; Frank E. Ritter

2004-01-01

46

Modeling the internal combustion engine  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

47

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

48

Al-Shihabi and Mourant 1 Toward More Realistic Driving Behavior Models for Autonomous  

E-print Network

in Driving Simulators Talal Al-Shihabi Virtual Environments Laboratory 334 Snell Engineering CenterAl-Shihabi and Mourant 1 Toward More Realistic Driving Behavior Models for Autonomous Vehicles. Mourant (Corresponding Author) Virtual Environments Laboratory 334 Snell Engineering Center Northeastern

49

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

50

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

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

51

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

52

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.

53

Engine Structures Modeling Software System (ESMOSS)  

NASA Technical Reports Server (NTRS)

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

1991-01-01

54

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

PubMed

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

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

2014-09-01

55

Simulation Model Driven Engineering for Manufacturing Cell  

E-print Network

Simulation Model Driven Engineering for Manufacturing Cell Hironori Hibino1 , Toshihiro Inukai2 Abstract. In our research, the simulation model driven engineering for manufacturing cell (SMDE on the simulation model and to extend the range of control applications and simulation applications using the PC

Paris-Sud XI, Université de

56

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

57

A Structural Model of Aircraft Engine Maintenance  

Microsoft Academic Search

We develop and estimate a simple regenerative optimal stopping model of aircraft engine maintenance that attempts to describe the behaviour of airline maintenance personnel. The model assumes that the decision to send an engine to the shop for overhaul is the solution to a stochastic dynamic programming problem that trades off the expected cost of continuing operation with the attendant

D. Mark Kennet

1994-01-01

58

Model-Driven Ontology Engineering  

Microsoft Academic Search

W3C's Semantic Web provides a common framework that allows data to be shared and reused across application and enterprise. As the Semantic Web shapes the future of the Web, it becomes more and more important in software engineering and enterprise application development. While existing ontology engineering tools provide a stack of ontology management support and are used successfully in certain

Yue Pan; Guo Tong Xie; Li Ma; Yang Yang; Zhaoming Qiu; Juhnyoung Lee

2006-01-01

59

Spot the difference: engineered and natural nanoparticles in the environment-release, behavior, and fate.  

PubMed

The production and use of nanoparticles leads to the emission of manufactured or engineered nanoparticles into the environment. Those particles undergo many possible reactions and interactions in the environment they are exposed to. These reactions and the resulting behavior and fate of nanoparticles in the environment have been studied for decades through naturally occurring nanoparticulate (1-100?nm) and colloidal (1-1000?nm) substances. The knowledge gained from these investigations is nowhere near sufficiently complete to create a detailed model of the behavior and fate of engineered nanoparticles in the environment, but is a valuable starting point for the risk assessment of these novel materials. It is the aim of this Review to critically compare naturally observed processes with those found for engineered systems to identify the "nanospecific" properties of manufactured particles and describe critical knowledge gaps relevant for the risk assessment of manufactured nanomaterials in the environment. PMID:25348500

Wagner, Stephan; Gondikas, Andreas; Neubauer, Elisabeth; Hofmann, Thilo; von der Kammer, Frank

2014-11-10

60

Tasks and ontologies in engineering modelling  

Microsoft Academic Search

Constructing models of physical systems is a recurring activity in engineering problem solving. This paper presents a generic knowledge-level analysis of the task of engineering modelling. Starting from the premise that modelling is a design-like activity, it proposes the Specify-Construct-Assess (SCA) problem-solving method for decomposition of the modelling task. A second structuring principle is found in the distinction between and

Jan L. Top; Hans Akkermans

1994-01-01

61

A behavior model for persuasive design  

Microsoft Academic Search

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

B. J. Fogg

2009-01-01

62

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

63

Textual Views in Model Driven Engineering  

Microsoft Academic Search

Building views on abstract models is one of the key concepts of model-driven engineering. Different views help to present concepts behind a model in a way that they can be understood and edited by different stakeholders or developers in different roles. Within graphical modelling several approaches exist allowing the definition of explicit holistic, partial or combined graphical views for models.On

Thomas Goldschmidt; Steffen Becker; Axel Uhl

2009-01-01

64

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

65

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

Federal Register 2010, 2011, 2012, 2013

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

2010-11-05

66

The Carousel Model of Leisure Behavior.  

ERIC Educational Resources Information Center

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

Pestle, Karin H.; And Others

1989-01-01

67

Laser docking sensor engineering model  

NASA Technical Reports Server (NTRS)

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

Dekome, Kent; Barr, Joseph M.

1991-01-01

68

Teaching Behavioral Modeling and Simulation Techniques for Power Electronics Courses  

Microsoft Academic Search

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

Alexander Abramovitz

2011-01-01

69

Micromechanical Models for Bending Behavior of Woven Composites  

E-print Network

Micromechanical Models for Bending Behavior of Woven Composites ¨O. Soykasap Department of Engineering, University of Cambridge Trumpington Street, Cambridge, CB2 1PZ, UK Thin woven composites have laminates made from woven composites disagree with the estimates of bending stiffness and strains using CLT

Soykasap, Omer

70

Teaching Behavioral Modeling and Simulation Techniques for Power Electronics Courses  

ERIC Educational Resources Information Center

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

Abramovitz, A.

2011-01-01

71

Measuring Model Rocket Engine Thrust Curves  

ERIC Educational Resources Information Center

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

Penn, Kim; Slaton, William V.

2010-01-01

72

Measurements and Models for Traffic Engineering  

E-print Network

Part 3 Measurements and Models for Traffic Engineering #12;Traffic Engineering · Goal: domain-wide control & management to ­ Satisfy performance goals ­ Use resources efficiently · Knobs: ­ Configuration & topology: provisioning, capacity planning ­ Routing: OSPF weights, MPLS tunnels, BGP policies,... ­ Traffic

Grossglauser, Matthias

73

An advanced model-based diagnosis engine  

NASA Technical Reports Server (NTRS)

We have developed a new and powerful diagnosis engine that overcomes the limitations of the existing systematic methods of general diagnosis through a two-fold approach. First, we propose a novel and compact reconstruction of the General Diagnosis Engine, one of the most fundamental approaches to model-based diagnoses. We then present a novel algorithmic approach for calculation of minimal diagnosis set.

Fijany, A.; Vatan, F.; Barrett, A.; James, M.; Mackey, R.

2003-01-01

74

Enterprise Modeling and Simulation Within Enterprise Engineering  

Microsoft Academic Search

One of the strengths of simulation as a method of inquiry and tool of study is its ability to provide a platform for breakthrough ideas in emerging interdisciplinary fields. In this article, the author defines enterprise engineering as an interdisciplinary field and discusses the role of modeling and simulation and its potential in enterprise engineering. In particular, the author discusses

Joseph Barjis

2011-01-01

75

Clinician Search Behaviors May Be Influenced by Search Engine Design  

PubMed Central

Background Searching the Web for documents using information retrieval systems plays an important part in clinicians’ practice of evidence-based medicine. While much research focuses on the design of methods to retrieve documents, there has been little examination of the way different search engine capabilities influence clinician search behaviors. Objectives Previous studies have shown that use of task-based search engines allows for faster searches with no loss of decision accuracy compared with resource-based engines. We hypothesized that changes in search behaviors may explain these differences. Methods In all, 75 clinicians (44 doctors and 31 clinical nurse consultants) were randomized to use either a resource-based or a task-based version of a clinical information retrieval system to answer questions about 8 clinical scenarios in a controlled setting in a university computer laboratory. Clinicians using the resource-based system could select 1 of 6 resources, such as PubMed; clinicians using the task-based system could select 1 of 6 clinical tasks, such as diagnosis. Clinicians in both systems could reformulate search queries. System logs unobtrusively capturing clinicians’ interactions with the systems were coded and analyzed for clinicians’ search actions and query reformulation strategies. Results The most frequent search action of clinicians using the resource-based system was to explore a new resource with the same query, that is, these clinicians exhibited a “breadth-first” search behaviour. Of 1398 search actions, clinicians using the resource-based system conducted 401 (28.7%, 95% confidence interval [CI] 26.37-31.11) in this way. In contrast, the majority of clinicians using the task-based system exhibited a “depth-first” search behavior in which they reformulated query keywords while keeping to the same task profiles. Of 585 search actions conducted by clinicians using the task-based system, 379 (64.8%, 95% CI 60.83-68.55) were conducted in this way. Conclusions This study provides evidence that different search engine designs are associated with different user search behaviors. PMID:20601351

Coiera, Enrico; Zrimec, Tatjana; Compton, Paul

2010-01-01

76

Behavioral animal models of depression.  

PubMed

Depression is a chronic, recurring and potentially life-threatening illness that affects up to 20% of the population across the world. Despite its prevalence and considerable impact on human, little is known about its pathogenesis. One of the major reasons is the restricted availability of validated animal models due to the absence of consensus on the pathology and etiology of depression. Besides, some core symptoms such as depressed mood, feeling of worthlessness, and recurring thoughts of death or suicide, are impossible to be modeled on laboratory animals. Currently, the criteria for identifying animal models of depression rely on either of the 2 principles: actions of known antidepressants and responses to stress. This review mainly focuses on the most widely used animal models of depression, including learned helplessness, chronic mild stress, and social defeat paradigms. Also, the behavioral tests for screening antidepressants, such as forced swimming test and tail suspension test, are also discussed. The advantages and major drawbacks of each model are evaluated. In prospective, new techniques that will be beneficial for developing novel animal models or detecting depression are discussed. PMID:20651815

Yan, Hua-Cheng; Cao, Xiong; Das, Manas; Zhu, Xin-Hong; Gao, Tian-Ming

2010-08-01

77

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

78

Outer planet probe engineering model structural tests  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

79

Introducing Freshmen to Industrial Engineering Through Modeling  

ERIC Educational Resources Information Center

Describes a combination of lectures, experiments, and analysis with the aid of remote computer terminals that helps the engineering student grasp the fundamentals and implications of a mathematical model applied to a particular job situation. (MLH)

Engel, Joseph H.; And Others

1976-01-01

80

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.

81

Models of Attitude-Behavior Relations.  

ERIC Educational Resources Information Center

Three replications of a structural equation model for the prediction of behavior are tested, using a questionnaire assessing undergraduate students' attitudes, subjective norms, intentions, and behavior. The proposed models supersede the Fishbein-Ajzen theory in their ability to reflect the dynamics of attitude-behavior relations. (Author/RD)

Bentler, P. M.; Speckart, George

1979-01-01

82

COSYSMO: A Constructive Systems Engineering Cost Model Coming of Age  

Microsoft Academic Search

Building on the synergy between Systems Engineering and Software Engineering, the Center for Software Engineering (CSE) at the University of Southern California (USC), has initiated an effort to develop a parametric model to estimate Systems Engineering costs. The goal of this model, called COSYSMO (Constructive Systems Engineering Cost Model), is to more accurately estimate the time and effort associated with

Ricardo Valerdi; Barry W. Boehm; Donald J. Reifer

2003-01-01

83

A fuzzy behavior based microscopic traffic model  

Microsoft Academic Search

This paper deals with the problem of a human behavior based Microscopic Traffic Model. In this work, a fuzzified two point model is implemented for modeling the low level control behavior and a Fuzzy Multi Criteria Decision Making is implemented for modeling the high level control actions of the driver. As a result, different influential parameters such as the driver's

M. A. Tavallaei; S. Khanmohammadi; I. Hasanzadeh

2008-01-01

84

Systems engineering in the Large Synoptic Survey Telescope project: an application of model based systems engineering  

NASA Astrophysics Data System (ADS)

The Large Synoptic Survey Telescope project was an early adopter of SysML and Model Based Systems Engineering practices. The LSST project began using MBSE for requirements engineering beginning in 2006 shortly after the initial release of the first SysML standard. Out of this early work the LSST's MBSE effort has grown to include system requirements, operational use cases, physical system definition, interfaces, and system states along with behavior sequences and activities. In this paper we describe our approach and methodology for cross-linking these system elements over the three classical systems engineering domains - requirement, functional and physical - into the LSST System Architecture model. We also show how this model is used as the central element to the overall project systems engineering effort. More recently we have begun to use the cross-linked modeled system architecture to develop and plan the system verification and test process. In presenting this work we also describe "lessons learned" from several missteps the project has had with MBSE. Lastly, we conclude by summarizing the overall status of the LSST's System Architecture model and our plans for the future as the LSST heads toward construction.

Claver, C. F.; Selvy, Brian M.; Angeli, George; Delgado, Francisco; Dubois-Felsmann, Gregory; Hascall, Patrick; Lotz, Paul; Marshall, Stuart; Schumacher, German; Sebag, Jacques

2014-08-01

85

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

86

Modeling Dynamic Engineering Design Processes in PSI  

Microsoft Academic Search

One way to make engineering design effective and efficient is to make its processes flexible - i.e. self-adjusting, self-configuring, and self- optimizing at run time. The paper presents the descriptive part of the Dynamic Engineering Design Process (DEDP) modeling framework developed in PSI1 project. The project aims to build a software tool assisting managers to analyze and enhance the productivity

Vadim Ermolayev; Eyck Jentzsch; Oleg Karsayev; Natalya Keberle; Wolf-ekkehard Matzke; Vladimir Samoilov

2005-01-01

87

Spontaneous and genetically engineered animal models  

Microsoft Academic Search

The preclinical development of anticancer drugs has been based primarily on the transplantation of murine or human cancers into mice. Alternatives to these transplantation models are animals that naturally develop cancers with features relevant to the human disease. The first group of these models arises in mice that are genetically engineered to develop cancer. The second group includes pet dogs

K Hansen; C Khanna

2004-01-01

88

Hybrid rocket engine, theoretical model and experiment  

Microsoft Academic Search

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

Teodor-Viorel Chelaru; Florin Mingireanu

2011-01-01

89

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

90

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, Patrick H [ORNL; Mirin, Arthur [Lawrence Livermore National Laboratory (LLNL); Drake, John B [ORNL; Sawyer, William B. [Swiss Federal Institute of Technology

2006-01-01

91

Network Engineering for Agile Belief Network Models  

Microsoft Academic Search

The construction of a large, complex belief network model, like any major system development effort, requires a structured process to manage system design and development. This paper describes a belief network engineering process based on the spiral system lifecycle model. The problem of specifying numerical probability distributions for random variables in a belief network is best treated not in isolation,

Kathryn Blackmond Laskey; Suzanne M. Mahoney

2000-01-01

92

Directable Behavior Models for Virtual Driving Scenarios  

Microsoft Academic Search

In this paper we present a model for autonomous driving behavior useful for creating ambient trafficas well as experiment specific scenarios for driving simulation. This model follows roadways, obeyingthe rules of the road. It reacts to nearby vehicles and traffic control devices. The model supports arange of behaviors including passing, lane changes, and safe navigation through intersections. Themodel is parametrized

James Cremer; Joseph Kearney; Peter Willemsen

1997-01-01

93

Modeling Imitational Behavior Via Social Comparison Theory  

Microsoft Academic Search

Modeling crowd behaviors is an important challenge for intelligent virtual agents. We propose a general cognitive model of\\u000a simulating crowd behaviors, based on Festinger’s Social Comparison Theory (SCT), a prominent social psychology theory. We\\u000a present the use of the SCT model (using the Soar cognitive architecture) in the generation of imitational behavior in loosely-coupled\\u000a groups and show that SCT generates

Natalie Fridman; Gal A. Kaminka

2007-01-01

94

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

95

Mutation-based Model Synthesis in Model Driven Engineering  

Microsoft Academic Search

With the increasing use of models for software development and the emergence of model-driven engineering, it has become important to build accurate and precise models that present certain characteristics. Model transformation testing is a domain that requires generating a large number of models that satisfy coverage properties (cover the code of the transformation or the structure of the metamodel). However,

Sagar Sen; Benoit Baudry

2006-01-01

96

Thermal barrier coating life modeling in aircraft gas turbine engines  

NASA Technical Reports Server (NTRS)

Analytical models for predicting ceramic thermal barrier coating (TBC) spalling life in aircraft gas turbine engines are presented. Electron beam-physical vapor deposited (EB-PVD) and plasma sprayed TBC systems are discussed. An overview of the following TBC spalling mechanisms is presented: metal oxidation at the ceramic-metal interface, ceramic-metal interface stress singularities at edges and corners, ceramic-metal interface stresses caused by radius of curvature and interface roughness, material properties and mechanical behavior, temperature gradients, component design features and object impact damage. TBC spalling life analytical models are proposed based on observations of TBC spalling and plausible failure theories. TBC spalling was assumed to occur when the imposed stresses exceed the material strength (at or near the ceramic-metal interface). TBC failure knowledge gaps caused by lack of experimental evidence and analytical understanding are noted. The analytical models are considered initial engineering approaches that capture observed TBC failure trends.

Nissley, David M.

1995-01-01

97

Multiscale modeling of biomedical, biological, and behavioral systems (part 2) [Introduction to special issue  

Microsoft Academic Search

In this issue, the first article by Sander et al. describes a multiscale model that captures both the macroscopic and the microscopic behavior of bioengineered tissue. This study nicely brings together tissue engineering, polarimetric imaging, and MSM to provide a basis for rational design of engineered tissues. The second article by Rangan et al. presents a multiscale computational model of

R. J. White; G. C. Y. Peng; S. S. Demir

2009-01-01

98

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

99

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

100

Modeling the network forensics behaviors  

Microsoft Academic Search

Network forensics is a new coming approach to the network security. However, this field is not very clear to the new researchers. In this paper, we discuss the network forensics behaviors systematically from both the technical view and legal view. The goal of discussion is to outline the formalization and standardization of the network forensics behaviors. To our knowledge, this

Wei Ren; Hai Jin

2005-01-01

101

Data modelling versus ontology engineering  

Microsoft Academic Search

Ontologies in current computer science parlance are computer based resources that represent agreed domain semantics. Unlike data models, the fundamental asset of ontologies is their relative independence of particular applications, i.e. an ontology consists of relatively generic knowledge that can be reused by different kinds of applications\\/tasks. The first part of this paper concerns some aspects that help to understand

Peter Spyns; Robert Meersman; Mustafa Jarrar

2002-01-01

102

Modeling Imitational Behavior Via Social Comparison Theory  

E-print Network

(using the Soar cognitive architecture) in the generation of imitational behavior in loosely the implementation of SCT model in Soar cognitive architecture. We evaluate the use of SCT in the generation virtual agents. We propose a general cognitive model of simu- lating crowd behaviors, based on Festinger

Kaminka, Gal A.

103

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

Federal Register 2010, 2011, 2012, 2013

...Directives; Austro Engine GmbH Model E4 Diesel Piston Engines AGENCY: Federal Aviation...contact Austro Engine GmbH, Rudolf-Diesel-Strasse 11, A-2700 Weiner Neustadt...this AD will affect about 32 model E4 diesel piston engines, installed on...

2011-09-01

104

76 FR 33660 - Airworthiness Directives; Austro Engine GmbH Model E4 Diesel Piston Engines  

Federal Register 2010, 2011, 2012, 2013

...Directives; Austro Engine GmbH Model E4 Diesel Piston Engines AGENCY: Federal Aviation...contact Austro Engine GmbH, Rudolf-Diesel-Strasse 11, A-2700 Weiner Neustadt...2010), for Austro Engine GmbH model E4 diesel [[Page 33661

2011-06-09

105

Peer Models: Effects on Children's Achievement Behaviors.  

ERIC Educational Resources Information Center

This experiment investigated how sex of model and type of modeled behavior influenced achievement outcomes among elementary school children who had experienced difficulties learning mathematical skills in school. Children observed either a same- or opposite-sex peer model demonstrate either rapid (mastery model) or gradual (coping model

Schunk, Dale H.; And Others

106

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

107

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

108

A Cost Model for Ontology Engineering  

Microsoft Academic Search

In this report we propose a methodology for cost estimation for on- tologies and analyze cost factors implied in the engineering process. We examine the appropriateness of a COCOMO-like parametric approach to ontology cost estimation and propose a non-calibrated ontology cost model, which is to be continuously refined along with the collection of empiric data on person month eorts invested

Elena Paslaru Bontas; Malgorzata Mochol

109

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

110

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

111

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

112

Modeling dad: animal models of paternal behavior.  

PubMed

In humans, paternal behaviors have a strong influence on the emotional and social development of children. Fathers, more frequently than mothers, leave the family nucleus, and/or become abusive, leading to offspring that are more likely to grow under stressful conditions and greater susceptibility to abnormal health and social outcomes. Literature on parental behaviors, human or animal, has primarily focused on the interactions between mothers and offspring, with little research directed at understanding paternal behavior. In animal studies, experimenters correlate paternal behaviors with those seen in rodent or primate mothers, often under situations in which behaviors such as nest protection, huddling, pup grooming, and retrieval are artificially induced. In humans, the majority of the studies have looked at paralleling hormonal changes in fathers with those occurring in mothers, or observed paternal behaviors in populations with specific anthropological backgrounds. These studies reveal commonalities in parental behaviors and their underlying neural circuits. However, this work highlights the possibility that paternal behavior has components that are strictly masculine with unique neurobiological mechanisms. This review summarizes this information and provides a current view of a topic that needs further exploration. PMID:19744516

Kentner, Amanda C; Abizaid, Alfonso; Bielajew, Catherine

2010-03-01

113

Reverse engineering the structural and acoustic behavior of a stradivari violin  

NASA Astrophysics Data System (ADS)

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

Pyrkosz, Michael

114

Modeling of Multi-Tube Pulse Detonation Engine Operation  

NASA Technical Reports Server (NTRS)

The present paper explores some preliminary issues concerning the operational characteristics of multiple-tube pulsed detonation engines (PDEs). The study is based on a two-dimensional analysis of the first-pulse operation of two detonation tubes exhausting through a common nozzle. Computations are first performed to assess isolated tube behavior followed by results for multi-tube flow phenomena. The computations are based on an eight-species, finite-rate transient flow-field model. The results serve as an important precursor to understanding appropriate propellant fill procedures and shock wave propagation in multi-tube, multi-dimensional simulations. Differences in behavior between single and multi-tube PDE models are discussed, The influence of multi-tube geometry and the preferred times for injecting the fresh propellant mixture during multi-tube PDE operation are studied.

Ebrahimi, Houshang B.; Mohanraj, Rajendran; Merkle, Charles L.

2001-01-01

115

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

116

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

117

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

118

Hierarchical models of behavior and prefrontal function  

PubMed Central

The recognition of hierarchical structure in human behavior was one of the founding insights of the cognitive revolution. Despite decades of research, however, the computational mechanisms underlying hierarchically organized behavior are still not fully understood. Recent findings from behavioral and neuroscientific research have fueled a resurgence of interest in the problem, inspiring a new generation of computational models. In addition to developing some classic proposals, these models also break fresh ground, teasing apart different forms of hierarchical structure, placing a new focus on the issue of learning, and addressing recent findings concerning the representation of behavioral hierarchies within the prefrontal cortex. While offering explanations for some key aspects of behavior and functional neuroanatomy, the latest models also pose new questions for empirical research. PMID:18420448

Botvinick, Matthew M.

2010-01-01

119

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... the actual wellbore radius. Previous solutions were modified to include the effect of enlarged wellbore radius, and thus enable the engineer to deal with negative as well as positive skin. Wattenbargcr and Ramey studied the importance of wellbore storage...

Rattu, Bungen Christina

2012-06-07

120

Software-Engineering Process Simulation (SEPS) model  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

121

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

122

Center for Behavioral Intervention Technologies (CBITs) The Center for Behavioral Intervention Technologies (CBITs) is part of the Center for Engineering and Health of  

E-print Network

of faculty and researchers who integrate behavioral science, information Center for Behavioral Intervention Technologies (CBITs) The Center for Behavioral Intervention Technologies (CBITs) is part of the Center for Engineering

Chisholm, Rex L.

123

Modeling OPEC behavior: economic and political alternatives  

Microsoft Academic Search

The predominant approach to modeling OPEC behavior depends upon the assumption that economic self-interest provides the best predictor of the cartel's price and production strategy. With rational monopoly behavior, the exogenous characteristics of the oil market determine an optimal price path for the group. But OPEC members have diverse economic as well as political goals. And uncertainty about oil market

2009-01-01

124

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

125

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

126

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

127

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

128

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

129

BIOMASS REBURNING - MODELING/ENGINEERING STUDIES  

SciTech Connect

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

Vladimir Zamansky; Chris Lindsey

1999-10-29

130

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

131

Cost estimation for model-driven engineering  

Microsoft Academic Search

Cost estimation studies in model-driven engineering (MDE) are scarce; first, due to difficulty in quantifying qualitative characteristics of MDE that supposedly influence software development effort and second, due to the complexity of measuring varied artifacts that are generated and used in an end-to-end MDE toolset. A cost estimation approach is therefore needed that can incorporate characteristics of MDE that affect

Sagar Sunkle; Vinay Kulkarni

2012-01-01

132

Survey of Economic Models of Criminal Behavior.  

National Technical Information Service (NTIS)

Economic theories of criminal behavior premise the criminal as rational actor engaged in a calculus of incentives and disincentives. The fundamental model assumes the actor allocates time between legitimate and illegitimate activities, with time allocatio...

W. J. Haga

1987-01-01

133

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

134

Application of Tracing Techniques in Model-Driven Performance Engineering  

Microsoft Academic Search

In our previous work we proposed Model-Driven Performance Engineering (MDPE) as a methodology to integrate performance engi- neering into the model-driven engineering process. MDPE enables do- main experts, who generally lack performance expertise, to prot from performance engineering by automating the performance analysis process using model transformations. A crucial part of this automated process is to give performance prediction feedback

Mathias Fritzsche; Jendrik Johannes; Steen Zschaler; Anatoly Zherebtsov; Alexander Terekhov

135

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

136

Reverse Engineering Component Models for Quality Predictions  

Microsoft Academic Search

Abstract—Legacy,applications,are,still widely,spread. If a need to change deployment or update its functionality arises, it becomes,difficult to estimate,the performance,impact,of such modifications,due,to absence,of corresponding,models. In this paper, we present an extendable integrated environment based on Eclipse developed,in the scope,of the Q-ImPrESS project for reverse engineering,of legacy applications,(in C\\/C++\\/Java). The Q-ImPrESS project aims,at modeling,quality attributes at an architectural level and,allows for choosing,the most,suitable

Steffen Becker; Michael Hauck; Mircea Trifu; Klaus Krogmann; Jan Kofron

2010-01-01

137

Generomak: Fusion physics, engineering and costing model  

SciTech Connect

A generic fusion physics, engineering and economics model (Generomak) was developed as a means of performing consistent analysis of the economic viability of alternative magnetic fusion reactors. The original Generomak model developed at Oak Ridge by Sheffield was expanded for the analyses of the Senior Committee on Environmental Safety and Economics of Magnetic Fusion Energy (ESECOM). This report describes the Generomak code as used by ESECOM. The input data used for each of the ten ESECOM fusion plants and the Generomak code output for each case is given. 14 refs., 3 figs., 17 tabs.

Delene, J.G.; Krakowski, R.A.; Sheffield, J.; Dory, R.A.

1988-06-01

138

A planning model for ABET Engineering Criteria 2000 [engineering education  

Microsoft Academic Search

ABET Engineering Criteria 2000 provides a new basis for accrediting engineering education programs in the USA. Conceptually, the new basis is straightforward with each program being required to have education objectives along with processes that demonstrate the objectives are met through learning outcomes and an ongoing commitment to improvement. Despite the simplicity of the basic concept, initial implementation is proving

M. D. Aldridge; L. Benefield

1997-01-01

139

A maintenance model for clinical engineering.  

PubMed

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

Johnston, G I

1985-01-01

140

Engineering model development and test results  

NASA Astrophysics Data System (ADS)

The correctability of the primary mirror spherical error in the Wide Field/Planetary Camera (WF/PC) is sensitive to the precise alignment of the incoming aberrated beam onto the corrective elements. Articulating fold mirrors that provide +/- 1 milliradian of tilt in 2 axes are required to allow for alignment corrections in orbit as part of the fix for the Hubble space telescope. An engineering study was made by Itek Optical Systems and the Jet Propulsion Laboratory (JPL) to investigate replacement of fixed fold mirrors within the existing WF/PC optical bench with articulating mirrors. The study contract developed the base line requirements, established the suitability of lead magnesium niobate (PMN) actuators and evaluated several tilt mechanism concepts. Two engineering model articulating mirrors were produced to demonstrate the function of the tilt mechanism to provide +/- 1 milliradian of tilt, packaging within the space constraints and manufacturing techniques including the machining of the invar tilt mechanism and lightweight glass mirrors. The success of the engineering models led to the follow on design and fabrication of 3 flight mirrors that have been incorporated into the WF/PC to be placed into the Hubble Space Telescope as part of the servicing mission scheduled for late 1993.

Wellman, John A.

1993-08-01

141

Reverse Engineering MAC: A Non-Cooperative Game Model  

E-print Network

Reverse Engineering MAC: A Non-Cooperative Game Model Jianwei Huang Information Engineering. Huang (CUHK) Reverse Engineering MAC Nov. 2007 1 / 21 #12;Summary Reverse engineering: Given the missing piece (on MAC) for existing layers 2-4 protocols on rigorous mathematical foundation J. Huang

Huang, Jianwei

142

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

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

143

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

PubMed

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

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

2014-01-01

144

ILLINOIS -RAILROAD ENGINEERING Understanding the Transition Behavior of  

E-print Network

- RAILROAD ENGINEERING Outline � Introduction � Transition zones � Why study grade crossings? � Grade of the fourth sleeper away from the level crossing being studied � Speed of the train: 65 mph (104 km;Slide 12 ILLINOIS - RAILROAD ENGINEERING Possible Solutions? � Close the crossing � Grade separate

Illinois at Urbana-Champaign, University of

145

Energy Efficient Engine Exhaust Mixer Model Technology  

NASA Technical Reports Server (NTRS)

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

Kozlowski, H.; Larkin, M.

1981-01-01

146

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

147

Modeling and Personal Space Behavior in Children  

Microsoft Academic Search

Approach vs. be approached behavioral measures of personal space were taken on 102 fifth and sixth grade children, each of whom was assigned to one of three groups: (a) Model-Close condition, (b) Model Far condition, and (c) No-Model Control group. A male peer served as model (M), and a 41-year-old female served as the object person. Results revealed a strong

Kent G. Bailey; John J. Hartnett; Hilda W. Glover

1973-01-01

148

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

149

Modeling of the conformational behavior of polyvinylchloride  

Microsoft Academic Search

The conformational behavior of polyvinylchloride was modeled by calculations of different conformers, rotational barriers, and rotation-energy profile diagrams of some model compounds, such as 1,3-dichloropropane, 1,3,5-trichloropentane, 1,3,5,7-tetrachloroheptane, 2,4-dichloropentane and 2,4,6-trichloropentane using the PCILO-and MM2-methods. These calculations allow some assertions about the conformational behavior of PVC. It was found that already a simple increment system derived from the model molecules is

M. Bölke; M. Möllhoff; P. Hallpap; J. R. Lochmann

1991-01-01

150

Statistical Validation of Engineering and Scientific Models: Background  

SciTech Connect

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

Hills, Richard G.; Trucano, Timothy G.

1999-05-01

151

Modeling behavioral considerations related to information security.  

SciTech Connect

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

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

2011-01-01

152

Structural and behavioral equivalence of simulation models  

Microsoft Academic Search

It M sometimes desu-able to know when two different discrete-event simulation models are, in some sense, interchangeable; that is, whether or not the two models always have the same output when run under identical experimental conditions. This notion of behavioral equivalence, while conceptually simple, is difficult to define in a manner that is both useful and testable. It is difficult

Enver Yücesan; Lee Schruben

1992-01-01

153

Model solar flares and their homologous behavior  

Microsoft Academic Search

A model describing physical processes of solar flares and their homologous behavior is presented based on resistive MHD simulations of magnetic arcade evolution subject to continuous shear-increasing footpoint motions. It is proposed in the model that the individual flaring process encompasses magnetic reconnection of arcade field lines, generation of magnetic islands in the magnetic arcade, and coalescence of magnetic islands.

G. S. Choe; C. Z. Cheng

2000-01-01

154

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

155

Modeling of Injection-Rate Shaping in Diesel Engine Combustion  

E-print Network

Modeling of Injection-Rate Shaping in Diesel Engine Combustion Vivak Luckhchoura #12;#12;Modeling of Injection-Rate Shaping in Diesel Engine Combustion Von der Fakult¨at f¨ur Maschinenwesen der Rheinisch . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Literature Survey 5 2.1 Combustion in Direct Injection Diesel Engines . . . . . . . . . . . . 5

Peters, Norbert

156

TOWARDS AN ABILITY MODEL FOR SOFTWARE ENGINEERING APPRENTICESHIP  

E-print Network

software engineer. The ISO/IEC 12207 standard is a reference framework of software engineering processes. The ability model establishes a structure that directly supports the personal and team construction processTOWARDS AN ABILITY MODEL FOR SOFTWARE ENGINEERING APPRENTICESHIP Vincent Ribaud and Philippe Saliou

Paris-Sud XI, Université de

157

Modeling for typical engineering processes in intelligent virtual spaces  

Microsoft Academic Search

Product engineering activities such as design, analysis, manufacturing planning, and control of equipment rely upon computer models. Descriptions of engineering objects such as elements and structures of products, results of tests and analyses, and engineering processes for design, analysis, and manufacturing of products have developed into very complex integrated data structures. Application of these complex product models has been extended

Laszlo Horvath; I. J. Rudas

2006-01-01

158

Models of Multi-Category Choice Behavior  

Microsoft Academic Search

Given the advent of basket-level purchasing data of households, choice modelers are actively engaged in the development of\\u000a statistical and econometric models of multi-category choice behavior of households. This paper reviews current developments\\u000a in this area of research, discussing the modeling methodologies that have been used, the empirical findings that have emerged\\u000a so far, and directions for future research. We

P. B. Seetharaman; Siddhartha Chib; Andrew Ainslie; Peter Boatwright; Tat Chan; Sachin Gupta; Nitin Mehta; Vithala Rao; Andrei Strijnev

2005-01-01

159

PARAMETRIC MODEL OF AN AEROSPIKE ROCKET ENGINE  

Microsoft Academic Search

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

J. J. Korte

2000-01-01

160

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

161

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

162

Thermal barrier coating life modeling in aircraft gas turbine engines  

NASA Technical Reports Server (NTRS)

Analytical models useful for predicting ceramic thermal barrier coating (TBC) spalling life in aircraft gas turbine engines are presented. Electron beam-physical vapor deposited (EB-PVD) and plasma sprayed TBC systems are discussed. TBC spalling was attributed to a combination of mechanisms such as metal oxidation at the ceramic-metal interface, ceramic-metal interface stress concentrations at free surfaces due to dissimilar materials, ceramic-metal interface stresses caused by local radius of curvature and interface roughness, material properties and mechanical behavior, transient temperature gradients across the ceramic layer and component design features. TBC spalling life analytical models were developed based on observations of TBC failure modes and plausible failure theories. TBC failure was assumed to occur when the imposed stresses exceeded the material strength (at or near the ceramic-metal interface). TBC failure knowledge gaps caused by lack of experimental evidence and analytical understanding are noted. The analytical models are considered initial engineering approaches that capture observed TBC failure trends.

Nissley, D. M.

1995-01-01

163

Investigating the effects of behavior constructs on academic persistence in engineering, creativity and risk-taking  

NASA Astrophysics Data System (ADS)

Increasingly over the last decade, engineering colleges across this nation have conducted research to identify factors that will help them better predict students' academic persistence in engineering. While initial efforts were aimed at predicting those who would graduate, recent efforts have been directed toward predicting who will persist to the second year, as it has been found that a substantial percentage of those who leave engineering do so during their first year. Prior research investigated the predictability of academic persistence using academic credentials such as grade point averages and SAT scores. However, recent research on academic persistence in engineering has suggested differences in students' behavior and students' levels of dissonance-induced stress, rather than differences in academic credentials, may distinguish persisters from non-persisters. One aspect of an individual's behavior, compliance, and behavior-related stress, referred to as dissonance-induced stress, are proposed to have an effect on academic persistence. Research shows compliance (or conformity) is diametrically opposed to creativity, which is essential to leadership and innovation in engineering. A similar relationship is likely to exist between compliance and risk-taking. This research investigated whether behavior and dissonance-induced stress are good predictors of academic persistence in engineering. This research also investigated relationships between behavior, creativity, and risk-taking. Students who were enrolled in a first-year Fundamentals in Engineering course (ENGR 112) were the subjects in this research. The Style Analysis Instrument was used to collect data regarding students' behavioral orientations. The Style Analysis Instrument provides both natural and adapted measures in four dimensions of human behavior: dominance, influence, steadiness, and compliance. The Creativity and Risk-Taking Instrument was used to collect data regarding students' creativity and risk-taking tendencies. Results indicate compliance has a statistically significant effect on academic persistence in engineering among first-year engineering students. However, the hypothesis regarding the effect of behavioral dissonance-induced stress was not supported. Results regarding relationships between the behavior variables used in this research and creativity and risk-taking imply that risk-taking is more related to behavior variables than creativity.

Deanes, Viveca K.

164

The Internet as recommendation engine : implications of online behavioral targeting  

E-print Network

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

Smith-Grieco, Anthony Nicoll

2010-01-01

165

Software Engineering Laboratory (SEL) cleanroom process model  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

166

Prairie dog engineering indirectly affects beetle movement behavior  

Microsoft Academic Search

Previous studies have shown that landscape structure influences animal movement and population structure. In this study, we show an indirect interaction between beetles and prairie dogs due to prairie dog ecosystem engineering. Gunnison's prairie dog (Cynomys gunnisoni Hollister) towns have more bare ground and are structurally less complex than adjacent unmodified grasslands. This results in bare ground facilitating beetle movement.

R. K. Bangert; C. N. Slobodchikoff

2004-01-01

167

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

NASA Astrophysics Data System (ADS)

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

Bowles, C.

2013-12-01

168

Safety evaluation using behavioral simulation models  

Microsoft Academic Search

This paper describes a design environment called ADEPT (advanced design environment prototype tool) which enables designers to assess the dependability of systems early in the design process using behavioral simulation models. ADEPT is an interactive graphical design environment which allows design and analysis of systems throughout the entire design cycle. ADEPT supports functional verification, performance evaluation, and dependability analysis early

Anup K. Ghosh; Barry W. Johnson; Joseph A. Profeta

1996-01-01

169

Using OOF to Model Mechanical Behavior of  

E-print Network

Using OOF to Model Mechanical Behavior of Thermal Barrier Coatings Mark R. Locatelli and Edwin R% Y2O3 Plasma Sprayed Thermal Barrier Coating 50 mm AM100 ZrO2 ­ MgO Free Standing Monolith more than on Advanced Ceramic Coatings Intl. Conf. on Advanced Ceramics & Composites Cocoa Beach, FL - January 15, 2002

Fuller, Edwin R.

170

Using Participatory Learning to Model Human Behavior  

Microsoft Academic Search

We discuss the need for addressing the issue of learning in human behavior modeling and social computing. We introduce and\\u000a describe the participatory learning paradigm. A formal system implementing this type of learning agent is provided. We then\\u000a extend this system so that it can learn from interval type observations.

Ronald R. Yager

171

Behavior Modeling for Decision Support within a  

E-print Network

- cient shipment of spares to the customers. Due to emergency situations such as aircraftBehavior Modeling for Decision Support within a Spare Parts Supply Chain by Jean Olivier Sens Luna, comprehension, and constant motivation during this journey. iii #12;Abstract A Spares Order Desk is a working

172

Modeling the flows of engineered nanomaterials during waste handling.  

PubMed

Little is known about the behavior of engineered nanomaterials (ENM) at the interface from the technosphere to the ecosphere. Previous modeling of ENM flows to the environment revealed that significant amounts of ENM enter the waste stream and therefore waste incineration plants and landfills. It is the aim of this study to model the flows of ENM during waste incineration and landfilling in greater depth by including a more detailed description of the different processes and considering ENM-specific transformation reactions. Four substances were modeled: nano-TiO2, nano-ZnO, nano-Ag and carbon nanotube (CNT). These ENM are representative for commonly used materials and products, illustrating a variety of ENM with different behavior. The modeling was performed for Switzerland where almost 100% of the municipal waste and sewage sludge are burned. The mass-based modeling showed that – despite several differences among the models for nano-TiO2, nano-ZnO and nano-Ag (e.g. partial dissolution of nano-ZnO in acid washing of exhaust air or fly ash) – the major ENM flows go from the waste incineration plant to the landfill as bottom ash. All other flows within the system boundary (e.g. with the fly ash) were predicted to be about one magnitude smaller than the bottom ash flow. A different ENM distribution was found for CNTs that are expected to burn to a large extent (94%) so that only insignificant amounts remain in the system. The results of the modeling show that waste incineration can have a strong influence on some ENM but that still the majority of the ENM-mass is expected to end up in landfills. PMID:24592442

Mueller, Nicole C; Buha, Jelena; Wang, Jing; Ulrich, Andrea; Nowack, Bernd

2013-01-01

173

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

174

Polynomial control of nonlinear turbocharged diesel engine model  

Microsoft Academic Search

In this paper, a polynomial controller based on the flatness property is designed for a diesel engine equipped with a variable geometry turbocharger (VGT) and an exhaust gas recirculation (EGR) valve. These two components have widely contributed to reduce the pollutant emission and to improve engine performance. For the control design, a simplified nonlinear model of the diesel engine is

M. Ayadi; Nicolas Langlois; H. Chafouk

2004-01-01

175

Application of artificial neural networks in engine modelling  

Microsoft Academic Search

A study was conducted to develop an accurate simulation tool with a small computer resource footprint for engine design. The modelling approach uses artificial neural networks (ANNs) based on multilayer perceptrons (MLPs). The ANN is used to represent engine in-cylinder processes by training the ANN to approximate computational fluid dynamics (CFD) simulation results of the engine. The ANN approach was

Y He; C J Rutland

2004-01-01

176

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

177

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

178

A practical biomedical engineering planning and decision making model  

Microsoft Academic Search

A quality planning and decision making model is presented. This model was developed by the quality improvement task group at the hospital. It presents a practical example of how such a model could be used by a biomedical engineering department

M. R. Ramirez

1995-01-01

179

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

180

Parameter Interrelation Based Modeling for Engineering  

Microsoft Academic Search

Engineering activities have been integrated into comprehensive computer systems. Powerful software is available for product development, production planning, equipment control, and product data management purposes. Lifecycle management of product related engineering is supported. It starts with an initial hand sketch about a product and finishes with recycling of that product. While advanced engineering systems are excellent frameworks, expected enhancements in

I. J. Rudas; L. Horvath

2006-01-01

181

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

Microsoft Academic Search

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

John Rust

1987-01-01

182

Combustion system CFD modeling at GE Aircraft Engines  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

183

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

184

Exploring Behavioral Markers of Long-Term Physical Activity Maintenance: A Case Study of System Identification Modeling within a Behavioral Intervention  

ERIC Educational Resources Information Center

Efficacious interventions to promote long-term maintenance of physical activity are not well understood. Engineers have developed methods to create dynamical system models for modeling idiographic (i.e., within-person) relationships within systems. In behavioral research, dynamical systems modeling may assist in decomposing intervention effects…

Hekler, Eric B.; Buman, Matthew P.; Poothakandiyil, Nikhil; Rivera, Daniel E.; Dzierzewski, Joseph M.; Aiken Morgan, Adrienne; McCrae, Christina S.; Roberts, Beverly L.; Marsiske, Michael; Giacobbi, Peter R., Jr.

2013-01-01

185

Behavioral Drive versus Behavioral Inertia in Evolution: A Null Model Approach  

Microsoft Academic Search

Some biologists embrace the classical view that changes in behavior inevitably initiate or drive evolutionary changes in other traits, yet others note that behavior sometimes inhibits evolutionary changes. Here we develop a null model that quantifies the impact of regulatory behaviors (specifically, thermoregulatory behaviors) on body temperature and on performance of ectotherms. We apply the model to data on a

B. Sinervo

2003-01-01

186

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

187

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

188

Modeling the model Characteristics and behavior of genetic algorithms  

E-print Network

Modeling the model Characteristics and behavior of genetic algorithms Author. Janeen Neri Progress in data files containing the fitness distribution and genetic algorithm specifications to be tested, and normalizes the fitness data for easier manipulation. A de- tailed pseudocode outline of the genetic algorithm

189

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

190

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

191

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

192

Animal Models for the Evaluation of Tissue Engineering Constructs  

Microsoft Academic Search

\\u000a In the last decade, tissue engineering has attracted a considerable amount of attention in medical research. Obviously, tissue-engineered\\u000a constructs need to be tested for their safety and efficacy before they can be used in the daily clinic. At present, animal\\u000a models offer the best possibility to do so. Each medical specialty favors its own specific model to test tissue-engineered\\u000a constructs.

Daniel A. W. Oortgiesen; Gert J. Meijer; Rob B. M. Vries; X. Frank Walboomers; John A. Jansen

193

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

194

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

195

Animal models of compulsive eating behavior.  

PubMed

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

2014-10-01

196

Modeling microdamage behavior of cortical bone.  

PubMed

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

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

2014-11-01

197

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

198

TEST STRATEGY FOR AERO-ENGINE STRUCTURAL DYNAMIC MODEL VALIDATION  

Microsoft Academic Search

Finite Element Models have been used for many years to predict the structural dynamic behaviour of aero- engines and to influence their design accordingly. The potential savings anticipated by such methods can only be realised if predictions are reliable, incorrect predictions might mislead the designers with serious consequences. Currently, a reliable validation of an aero-engine assembly model is only feasible

J. V. Garcia; D. J. Ewins

199

Fundamental Models for Fuel Cell Engineering Chao-Yang Wang*  

E-print Network

.4. Electron Transport 4740 3.5. Transient Phenomena 4741 3.6. Large-Scale Simulation 4742 3.7. Liquid WaterFundamental Models for Fuel Cell Engineering Chao-Yang Wang* Departments of Mechanical Engineering Fuel Cell Dynamics 4727 2.1. CFCD Model Equations 4728 2.2. Computational Aspects 4729 2.2.1. General

200

Evaluation of the Munich Method for modeling rocket engine performance  

Microsoft Academic Search

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

Frank J. Zeleznik

1993-01-01

201

A Framework for Modeling Privacy Requirements in Role Engineering  

Microsoft Academic Search

Privacy protection is important in many industries, such as healthcare and finance. Capturing and modeling privacy requirements in the early stages of system development is essential to provide high assurance of privacy protection to both stakeholders and consumers. This paper presents a framework for modeling privacy requirements in the role engineering process. Role engineering entails defining roles and permissions as

Qingfeng He; Annie I. Ant?n

202

Modeling for engineering processes in integrated robot definition  

Microsoft Academic Search

Engineering in product definition traditionally concentrates on building structures of parts and assemblies. Other objects such as analysis results, manufacturing methods, and equipment control programs are mapped to part and assembly definitions. This style of engineering has been realized in model and simulation based product development. Product data management systems as extensions to product modeling and simulation systems were forced

László Horváth; Imre J. Rudas

2010-01-01

203

Combining Ontology Alignment with Model Driven Engineering Techniques for Home  

E-print Network

Combining Ontology Alignment with Model Driven Engineering Techniques for Home Devices intro- duce an approach combining ontology alignment techniques with those of Model Driven Engineering domain to reach a dynamic service adap- tation. Keywords: SOA, Plug-n-play protocols, ontology alignment

204

Modeling Behaviors Selection in Crowd Simulation of Social Networks  

Microsoft Academic Search

This paper applies dynamics model to understand the origin of dominant behaviors in social networks that generally lead to emergence of personage, i.e. few leaders with overwhelming popular support. We commentate the notion of behaviors selection networks and introduce an improved social behaviors selection model for evolutionary dynamics of behaviors in social networks that exhibits a rich set of emergent

Xulin Xu; Xiaofeng Hu; Guangya Si; Zengqiang Chen

2010-01-01

205

Biomodel Engineering from Structure to Behavior Rainer Breitling1  

E-print Network

and need to start with a careful analysis of what the model is supposed to achieve (requirements capture systems. Keywords. Systems biology, Petri nets, computational modeling, differential equations 1 What analysis). In that context, it is most important to determine what kind of properties the biologists can

Gilbert, David

206

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

207

Box-Cox Mixed Logit Model for Travel Behavior Analysis  

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

208

Impact of modeling on adolescent suicidal behavior.  

PubMed

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

Insel, Beverly J; Gould, Madelyn S

2008-06-01

209

From conceptual modelling to requirements engineering  

Microsoft Academic Search

Conceptual m odelling is s ituated in the broader view of information systems requirements engineering. Requirements Engineering (RE) explores the objectives of different stakeholders and the ac tivities carried o ut by them t o meet t hese objectives in order to derive purposeful system requirements and therefore lead to b etter quality systems i.e. systems that m eet t

Colette Rolland; Naveen Prakash

2000-01-01

210

A technology empowerment model for engineering work  

Microsoft Academic Search

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

William J. Doll; Xiaodong Deng

2010-01-01

211

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

212

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

213

A bootstrap data methodology for sequential hybrid engine model building  

Microsoft Academic Search

The current evolution in on-board Propulsion Health Management (PHM) systems aimed at performing real-time engine diagnostics and prognostics has placed a greater demand on model accuracy and implementation speed. The complexities in assembling accurate physics based models for real-time operation has placed greater focus on the use of hybrid engine models employing some form of empirical modeling. A practical consideration

Al Volponi; Tom Brotherton

2005-01-01

214

A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES  

SciTech Connect

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

Blau, Peter Julian [ORNL

2009-11-01

215

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

216

Modeling Dependency with Copula: Implications to Engineers and Planners  

E-print Network

Modeling Dependency with Copula: Implications to Engineers and Planners Haizhong Wang, Ph Wang (OSU) Copula Modeling September 28, 2012 1 / 31 #12;Philosophy Modeling Philosophy - By George Box Essentially, all models are wrong, but some are useful. In Empirical Model-Building and Responses Surfaces

Bertini, Robert L.

217

Engineering based modeling activities for enhancing student communication and teamwork skills  

Microsoft Academic Search

This paper argues for a future-oriented, inclusion of engineering modeling activities in introductory engineering courses at the university level. Engineering model eliciting activities provide a rich source of meaningful engineering problem situations that capitalise on and extend students' existing mathematics and engineering learning and provide opportunities for enhancing student communication and teamwork skills. We give consideration here to engineering modeling

Nicholas Mousoulides

2010-01-01

218

Model-Based Test Driven Development of the Tefkat Model-Transformation Engine  

Microsoft Academic Search

Tefkat is an implementatio n of a rule - and pattern-based engine for the transformation of models defined using the Object Management Group's (OMG) Model-Driven Architecture (MDA). The process for the development of the engine included the concurrent development of a unit test suite for the engine. The test suite is constructed as a number of models, whose elements comprise

Jim Steel; Michael Lawley

2004-01-01

219

Shape-memory alloys: modelling and numerical simulations of the finite-strain superelastic behavior  

Microsoft Academic Search

Shape-memory alloys (SMA) show features not present in materials traditionally used in engineering; as a consequence, they are the basis for innovative applications. The present work proposes a step toward the development of a computation tool to be used during the design of SMA-based devices. To reach this goal, we develop a constitutive model which reproduce the superelastic behavior of

Ferdinando Auricchio; Robert L. Taylor

1997-01-01

220

Enhanced problem-based learning of power converter theories and implementations with behavior model simulations  

Microsoft Academic Search

Recently, the increasing demands for high efficient power conversion systems and the rapid advancement in semiconductor devices have made the power converter design technique a necessity for electronic engineers. To speed up the learning process, the problem- based learning approach and behavior model simulations are used to redesign the first power converter design course in Lunghwa University of Science and

Juing-Huei Su; Shun-Chung Wang; Chyi-Shyong Lee; Jiann-Jong Chen

2007-01-01

221

ASSISTANT PROFESSOR OF MECHANICAL ENGINEERING COMPUTATIONAL MODELING  

E-print Network

, and composite materials. Biomedical engineering applications will not be considered. This faculty position in the United States. The City offers a pleasant climate with excellent schools and abundant cultural

222

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

223

Modeling Pseudo-elastic Behavior of Springback  

SciTech Connect

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

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

2005-08-05

224

Rocketdyne/Westinghouse nuclear thermal rocket engine modeling  

NASA Technical Reports Server (NTRS)

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

Glass, James F.

1993-01-01

225

Multi-scale models for gene network engineering  

Microsoft Academic Search

With current advances in biological knowledge, the potential exists for engineering novel gene regulatory networks, which allow the timely control of protein expression. Genome projects identify the components of gene networks in biological organisms, gene after gene, and DNA microarray experiments discover the network connections. Yet, the static pictures these experiments give cannot provide insight on the dynamic behavior of

Yiannis N. Kaznessis

2006-01-01

226

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

227

XBRL TAXONOMY ENGINEERING. DEFINITION OF XBRL TAXONOMY DEVELOPMENT PROCESS MODEL.  

E-print Network

The growing number of eXtensible Business Reporting Language (XBRL) projects around the world and strong interest from bodies such as Security Exchange Commission in the United States (SEC), Central European Banking Supervisors in the European Union (CEBS) or International Accounting Standards Board (IASB) in building XBRL taxonomies demonstrate the need for formalisation and methodical approach to the process of the XBRL taxonomy development. Although many approaches exist in favour of software engineering and knowledge engineering, building an XBRL taxonomy is not about creating a software product or a knowledge-based system. It is creating a standardised taxonomy for a particular domain in order to enable standardised exchange of business reports. Nevertheless experiences learned from software and knowledge engineering areas are very useful for what can be called XBRL taxonomy engineering. On the other hand a clear parallel with the ontology engineering appears treating XBRL taxonomies as ontologies. The ontology development process could resemble in many aspects the way that XBRL taxonomies are created. The development process models presented in the literature are either project or software driven. Hence it is difficult to apply them as a generic and formal taxonomy development process model. This paper presents an approach to define a taxonomy development process model. The definition of the model is preceded with the status quo analysis of the existing development models known from software engineering and ontology engineering domains. The model definition itself is also based on empirical analysis of taxonomy development projects.

Technische Universität; Bergakademie Freiberg

228

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

229

Towards a methodology for ontology based model engineering  

Microsoft Academic Search

The philosophical discipline of Ontology is evolving towards an engineering discipline, and in this evolution the need for a principled methodology has clearly arisen. In this paper, we briefly discuss our recent work towards devel- oping a methodology for ontology-based model engineering. This methodology builds on previous methodology efforts, and is founded on important analytic notions that have been drawn

Nicola Guarino; Christopher Welty

2000-01-01

230

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

Microsoft Academic Search

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

Nancy J. Nersessian

2009-01-01

231

Engineering Process Coordination based on A Service Event Notification Model  

E-print Network

Engineering Process Coordination based on A Service Event Notification Model Jian Cao1, Jie Wang2 notification model based on grid service to coordinate different applications and human. The model takes for supporting process coordination. In this model, an event noti- fication server composed of a group of grid

Stanford University

232

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

233

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

ERIC Educational Resources Information Center

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

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

1998-01-01

234

Engineering complex topological memories from simple Abelian models  

SciTech Connect

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

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

2011-09-15

235

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

236

Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior  

NASA Astrophysics Data System (ADS)

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

Klem, B.; Swann, D.

2011-09-01

237

An analytical model of self-starting thermoacoustic engines  

NASA Astrophysics Data System (ADS)

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

Benavides, Efrýn Moreno

2006-06-01

238

Detecting mistakes in engineering models: the effects of experimental design  

E-print Network

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

Savoie, Troy B.

239

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.

240

Modeling and simulation of pedestrian behaviors in crowded places  

Microsoft Academic Search

Pedestrian simulation has many applications in computer games, military simulations, and animation systems. A realistic pedestrian simulation requires a realistic pedestrian behavioral model that takes into account the various behavioral aspects of a real pedestrian. In this article, we describe our work on such a model, which aims to generate human-like pedestrian behaviors. To this end, various important factors in

Wee Lit Koh; Suiping Zhou

2011-01-01

241

Performance Modeling of Stochastic Diagnosis Engines  

E-print Network

engine of Apollo 13: a group of eight astronauts and flight controllers monitoring the console activity in the Mission Operations Control Room (MOCR) during Apollo 13. When this picture was taken, the Apollo 13 moon home. The Apollo 13 space craft suffered from a quintuple fault: five simultaneous defects result- ing

Kuzmanov, Georgi

242

Modeling uncertainty in requirements engineering decision support  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

243

An Evaluation Model in Higher Engineering Education.  

ERIC Educational Resources Information Center

The difference between educational research and educational program evaluation is discussed, and the evaluation of a German engineering program experiencing high dropout rates is described. Data were gathered through guided personal interviews, written student reports, and student evaluations of lectures. Both curriculum and examinations were…

Ulbricht, Kurt G.

1983-01-01

244

A General Model for Engineering Databases  

Microsoft Academic Search

Due to the growing size of projects, rising costs and un- certainties of progress in development, the limitations of classical software engineering techniques have become ob- vious for many years now. Since the beginning of the 90ies quality assurance methods have been applied to soft- ware development. But ISO 9000 (1) standards and even company-specific quality assurance plans can only

Georg Heidenreich; Detlef Kips

245

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

E-print Network

, usually at the top and/or on the right of the page. The advertisement links are selected from an auction% of total advertising revenue [2]. There are many ways to define the list of displayed ads (the allocation the click results in a sell (Pay-Per-Transaction model). In most if not all cases, the Pay-Per-Click model

Paris-Sud XI, Université de

246

Outer planet probe engineering model thermal vacuum test  

NASA Technical Reports Server (NTRS)

A thermal vacuum test was performed on the engineering model of the outer planets atmospheric entry probe. Steady state runs at three simulated radioisotope heating unit loads and one transient run simulating the pre-entry power profile were made to determine the thermal characteristics of the engineering model. An analytic simulation of the model was correlated to the test data. Several steady state and one transient run were made with the model attached to the spacecraft adapter to determine the thermal interface between the model and the adapter.

Grote, M. G.

1977-01-01

247

Modeling and simulation of a hybrid-engine  

Microsoft Academic Search

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

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

1997-01-01

248

Man-machine processes in modeling based engineering activities  

Microsoft Academic Search

This paper discusses the man-machine interaction process in collaborative engineering systems where decisions of humans are assisted by computer procedures. Recent development in communication, multimedia, modeling and knowledge engineering techniques brought a new age in human-computer interface processes. Authors propose a model of the man-machine interaction that can be applied in CAD\\/CAM and flexible manufacturing systems. The paper is organized

Laszlo HorvAth; I. J. Rudas; J. A. Tenreiro Machado

1998-01-01

249

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

NASA Astrophysics Data System (ADS)

A large scale mixing and combustion model has been developed and studied through testing of two separate direct injection diesel engines. As a corollary, a shear layer ignition model was also developed for estimating the effects of key engine-related parameters on autoignition. Both models were developed for eventual inclusion into an engine cycle simulation for studying the effect of various key engine design parameters on overall power plant performance. The combustion model is comprised of two phases whose general behavior is characterized by a transient, representative time scale indicative of global mixing rate, mixing length scale, in-cylinder thermodynamic condition, and fuel properties. During the initial premixed phase, a mixing layer located on the injected fuel jet periphery is allowed to ignite and subsequently burn as controlled by the flame spread entrainment rate. After a determined delay, the second or mixing controlled phase is initiated and burns at a rate controlled by mixing, air utilization, impingement, and jet expansion. The shear layer ignition model is a transient, one-dimensional approach which accounts for fuel-air ratio stratification in the aforementioned mixing layer through assumed temperature and fuel specie profiles whose general shape is dictated by the conservation of energy. The first engine employed in this study was a Cummins VTA903 while the second engine was a heavy duty, Detroit Diesel (DDC) Series 60. In-cylinder pressure data was acquired for each engine and further analyzed using a commercially available thermodynamic engine cycle analysis code for net heat release rate analysis. Each engine was also instrumented to provide key details about the injection event such that reasonable estimates for autoignition were available for comparison with the proposed shear layer ignition model. Over a broad range of operating conditions for both engines, the mixing and combustion model exhibited predictive capability compared to experimentally determined net heat release rate profiles. Similarly, the shear layer ignition performed in an acceptable manner demonstrating superior performance compared to published empirical ignition delay models for diesel engines.

Schihl, Peter Joseph

250

Virtual intelligent space for engineers  

Microsoft Academic Search

Computer descriptions of engineering objects such as elements and structures of products, results of tests and analyses, and engineering processes for design, analysis, and manufacturing of products have been integrated. The resulted complex product models support lifecycle management of product data. Engineering utilizes advanced characteristics of modeling software such as analysis of behaviors, adaptive actions for controlled modifications of engineering

László Horváth; Imre J. Rudas

2005-01-01

251

Statistical validation of engineering and scientific models : bounds, calibration, and extrapolation.  

SciTech Connect

Numerical models of complex phenomena often contain approximations due to our inability to fully model the underlying physics, the excessive computational resources required to fully resolve the physics, the need to calibrate constitutive models, or in some cases, our ability to only bound behavior. Here we illustrate the relationship between approximation, calibration, extrapolation, and model validation through a series of examples that use the linear transient convective/dispersion equation to represent the nonlinear behavior of Burgers equation. While the use of these models represents a simplification relative to the types of systems we normally address in engineering and science, the present examples do support the tutorial nature of this document without obscuring the basic issues presented with unnecessarily complex models.

Dowding, Kevin J.; Hills, Richard Guy (New Mexico State University, Las Cruces, NM)

2005-04-01

252

Animal models of restricted repetitive behavior in autism  

PubMed Central

Restricted, repetitive behavior, along with deficits in social reciprocity and communication, is diagnostic of autism. Animal models relevant to this domain generally fall into three classes: repetitive behavior associated with targeted insults to the CNS; repetitive behavior induced by pharmacological agents; and repetitive behavior associated with restricted environments and experience. The extant literature provides potential models of the repetitive behavioral phenotype in autism rather than attempts to model the etiology or pathophysiology of restricted, repetitive behavior, as these are poorly understood. This review focuses on our work with deer mice which exhibit repetitive behaviors associated with environmental restriction. Repetitive behaviors are the most common category of abnormal behavior observed in confined animals and larger, more complex environments substantially reduce the development and expression of such behavior. Studies with this model, including environmental enrichment effects, suggest alterations in cortical-basal ganglia circuitry in the development and expression of repetitive behavior. Considerably more work needs to be done in this area, particularly in modeling the development of aberrant repetitive behavior. As mutant mouse models continue to proliferate, there should be a number of promising genetic models to pursue. PMID:16997392

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

2013-01-01

253

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

254

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

255

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

256

Quantum critical behavior in a graphenelike model  

SciTech Connect

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

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

2008-10-15

257

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

258

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

259

Using Graph Transformation for Practical Model Driven Software Engineering  

Microsoft Academic Search

Summary. Model transformations are one of the core technologies needed to apply OMG's model driven engineering concept for the construction of real world systems. Several formalisms are currently proposed for the specification of these model trans- formations. A suitable formalism is based on graph transformation systems and graph transformation rules. The chapter provides an overview about the needed concepts to

Lars Grunske; Leif Geiger; Albert Zundorf; Niels Van Eetvelde; Pieter Van Gorp; Daniel Varro

260

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

261

Supporting model driven engineering using the Marama meta toolset  

Microsoft Academic Search

The Marama project aims to develop an accessible and efficient meta toolset for rapidly constructing domain specific visual languages and environments to support integrated model driven engineering toolchains. Marama supports the rapid specification of visual notations and their underlying meta models, behavioural constraints, and model transformations. In this talk, I will describe the design and development of the open source

J. Hosking

2009-01-01

262

A Feature-based Framework for Model-Driven Engineering  

Microsoft Academic Search

Model-Driven Engineering (MDE) improves software engi- neering by providing an appropriate level of abstraction for an early review of a system design. Model transformations can be used to estab- lish a well-regulated development process. But existing transformation approaches still lack in connecting system requirements to the models realizing them. Furthermore, it is still dicult to integrate existing tools for particular

Susanne Busse; Helko Glathe; Thomas Stark; Jianhong Zhang

2007-01-01

263

Generic Models for Engineering Methods of Diverse Domains  

Microsoft Academic Search

The 3-layer architecture for methods consisting of the generic model, meta-model, and method layers is considered and the advantages of introducing the generic layer are brought out. It is argued that this layer helps in method selection, construction of methods in diverse domains and has the potential of rapidly engineering methods. A generic model is introduced and then instantiated from

Naveen Prakash; M. P. S. Bhatia

2002-01-01

264

ROLES OF ONTOLOGIES OF ENGINEERING ARTIFACTS FOR DESIGN KNOWLEDGE MODELING  

Microsoft Academic Search

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

YOSHINOBU KITAMURA

2006-01-01

265

An experimental study on a model Stirling engine car  

SciTech Connect

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

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

1999-07-01

266

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

267

Qualitative Simulation Model for Software Engineering Process  

Microsoft Academic Search

Software process simulation models hold out the promise of improving project planning and control. However, quantitative models require a very detailed understanding of the software process. In particular, process knowledge needs to be represented quantitatively which requires extensive, reliable software project data. When such data is lacking, quantitative models must impose severe constraints, restricting the value of the models. In

He Zhang; Ming Huo; Barbara Kitchenham; D. Ross Jeffery

2006-01-01

268

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

269

Mean Line Pump Flow Model in Rocket Engine System Simulation  

NASA Technical Reports Server (NTRS)

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

Veres, Joseph P.; Lavelle, Thomas M.

2000-01-01

270

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

271

[Explicit model for searching behavior of predator].  

PubMed

The authors present an approach for explicit modeling of spatio-temporal dynamics of predator-prey community. This approach is based on a reaction-diffusion-adjection PD (prey dependent) system. Local kinetics of population is determined by logistic reproduction function of prey, constant natural mortality of predator and Holling type 2 trophic function. Searching behavior of predator is described by the advective term in predator balance equation assuming the predator acceleration to be proportional to the prey density gradient. The model was studied with zero-flux boundary conditions. The influence of predator searching activity on the community dynamics, in particular, on the emergence of spatial heterogeneity, has been investigated by linear analysis and numerical simulations. It has been shown how searching activity may effect the persistence of species, stabilizing predator-prey interactions at very low level of pest density. It has been demonstrated that obtaining of such dynamic regimes does not require the use of complex trophic functions. PMID:11966215

Tiutiunov, Iu V; Sapukhina, N Iu; Senina, I N; Arditi, R

2002-01-01

272

A model for the transient behavior of an iron-core transformer  

E-print Network

A MODEL FOR THE TRANSIENT BEHAVIOR OF AN IRON-CORE TRANSFORMER A Thesis by JAMES EDWARD PLATTS Submitted to the Graduate College of the Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May... 1968 Major Subject: ELECTRICAL ENGINEERING A MODEL FOR THE TRANSIENT BEHAVIOR OF AN IRON-CORE TRANSFORMER A Thesis by JAMES EDWARD PLATTS Approved as to style and content by: airman of ommittee Hea o epartm t Member em er ( Member May 1968...

Platts, James Edward

2012-06-07

273

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

274

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

275

A Directable Vehicle Behavior Model for Virtual Driving Environments  

Microsoft Academic Search

In this paper we present a model for autonomous driving behavior useful for creating ambient traffic as well as experiment specific scenarios for driving simulation. This model follows roadways, obeying the rules of the road. It reacts to nearby vehicles and traffic control devices. The model supports a range of behaviors including passing, lane changes, and safe navigation through intersections.

James Cremer; Joseph Kearney; Peter Willemsen

1996-01-01

276

Generating transformation rules from examples for behavioral models  

Microsoft Academic Search

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

Marouane Kessentini; Manuel Wimmer; Houari Sahraoui; Mounir Boukadoum

2010-01-01

277

MODULAR MODELING OF ENGINEERING SYSTEMS USING  

E-print Network

modification of their internal equations. Modular simulation models have the property that their elements have models are developed using the systematic method of applying Kirchhoff Laws from a network topology (Chua

Radcliffe, Clark J.

278

Model Driven Engineering with Ontology Technologies  

Microsoft Academic Search

\\u000a Ontologies constitute formal models of some aspect of the world that may be used for drawing interesting logical conclusions\\u000a even for large models. Software models capture relevant characteristics of a software artifact to be developed, yet, most\\u000a often these software models have limited formal semantics, or the underlying (often graphical) software language varies from\\u000a case to case in a way

Steffen Staab; Tobias Walter; Gerd Gröner; Fernando Silva Parreiras

2010-01-01

279

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

280

Semi-quantitative Simulation Modeling of Software Engineering Process  

Microsoft Academic Search

\\u000a Software process simulation models hold out the promise of improving project planning and control. However, purely quantitative\\u000a models require a very detailed understanding of the software process, i.e. process knowledge represented quantitatively. When\\u000a such data is lacking, quantitative models impose severe constraints, restricting the model’s value. In contrast, qualitative\\u000a models display all possible behaviors but only in qualitative terms. This

He Zhang; Barbara Kitchenham

2006-01-01

281

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

282

Numerical Modeling of Pulse Detonation Rocket Engine Gasdynamics and Performance  

NASA Technical Reports Server (NTRS)

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

Morris, C. I.

2003-01-01

283

Bridging existing Web modeling languages to model-driven engineering: a metamodel for WebML  

Microsoft Academic Search

Metamodels are a prerequisite for model-driven engineering (MDE) in general and consequently for model-driven web engineering in particular. Various modeling languages, just as in the web engineering field, however, are not based on metamodels and standards but instead define proprietary languages rather focused on notational aspects. Thus, MDE techniques and tools can not be deployed for such languages. The WebML

Andrea Schauerhuber; Manuel Wimmer; Elisabeth Kapsammer

2006-01-01

284

Human Modeling for Ground Processing Human Factors Engineering Analysis  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

285

Human Modeling For Ground Processing Human Factors Engineering Analysis  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

286

An Introduction to Modeling Dynamic Behavior with Time Series Analysis  

Microsoft Academic Search

The need to model dynamic behavior in information systems arises in many contexts, such as characterizing the locality of file access patterns, evaluating the dynamic behavior of scheduling algorithms, and identifying performance problems by their time serial behavior. This paper provides an introduction to time series analysis (a statistical technique), and applies it to analyzing the performance of information systems.

Joseph L. Hellerstein

1993-01-01

287

Macro-and micro-behaviors in animal modeling of  

E-print Network

models (Do we have them?) Anxiety Depression (Do we have them?) Anxiety Depression Horizontal ActivityComplex behaviors, such as grooming, can be isolated and quantified in the assessment of anxiety www.lsa.umich.edu #12;Grooming Behavior · Ancient, innate behavior, common in rodents · Represents 30-50% of waking time

Kalueff, Allan V.

288

[Transactional model of suicidal behavior in the elderly].  

PubMed

General theories of suicidology are insufficient to explain the overproportional rate of suicidal behaviour in the elderly. The proposed transactional model represents a bio-psycho-social foundation of suicidal behavior in the elderly. The reciprocal interactions of biological, somatic, psychological and social factors in old age which may enhance suicidal behavior as a mode of problem-solving behavior are discussed. PMID:18286323

Schaller, S

2008-02-01

289

Variability in Human Behavior Modeling for Military Simulations  

Microsoft Academic Search

Capturing and encoding human variability is an increasingly important issue in human behavior models (HBMs) for military simulations. In this paper, we define variability, describe its importance in several military simulation applications, examine the sources of variability in human behavior, and outline an approach to variability that will allow us to explore approaches to low-cost, realistic variability in human behavior

Robert E. Wray; John E. Laird

2003-01-01

290

Modeling Motivations and Emotions as a Basis for Intelligent Behavior  

E-print Network

Modeling Motivations and Emotions as a Basis for Intelligent Behavior Dolores Ca � namero the first stage, the creature being a newborn whose behavior is strongly driven by motiva­ tional states---impulses by analogy with control systems. Motivations drive behavior selection and organization based on the notions

Cañamero, Lola

291

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.denis-vidal@math.univ-lille1.fr, ghislaine.joly-blanchard@utc.fr) Abstract: In order to optimize the performance of a diesel problems, modelling errors, Automotive emissions, Diesel engines 1. INTRODUCTION The automotive industry

Paris-Sud XI, Université de

292

f-COCOMO: fuzzy constructive cost model in software engineering  

Microsoft Academic Search

The COCOMO (constructive cost model) was established to improve the economic aspects of software development and management with respect to economic benefit. The fuzzy constructive cost model f-COCOMO is developed to give a more reasonable estimation for manpower and development time of a computer software project. The fuzziness involved in the cost estimation of software engineering is discussed, and its

Fei Zonglian; Liu Xihui

1992-01-01

293

Teaching Geometry through Dynamic Modeling in Introductory Engineering Graphics.  

ERIC Educational Resources Information Center

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

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

2003-01-01

294

Fixturing System in an Information Model Based Concurrent Engineering Environment  

Microsoft Academic Search

A distinguishing aspect of concurrent engineering is the intensive informa ion interchange between areas that are involved with the product life cycles. Shared information structures to integ ate different software applications have become necessary to support effectively the interchange o informa ion. While much work done in product model and manufactu ing model, there is a need to make them

Nilo T. Bugtai

2007-01-01

295

Model-Based Engineering Design Pilots at JPL  

Microsoft Academic Search

This paper discusses two recent formulation phase model-based engineering design pilot projects at the Jet Propulsion Laboratory. It describes how model-based functional and state analyses were synthesized and integrated with system performance simulation and mission planning then piloted in the formulation phase of two deep space missions.

Mark Kordon; Steve Wall; Henry Stone; William Blume; Joseph Skipper; Mitch Ingham; Joe Neelon; James Chase; Ron Baalke; David Hanks; Jose Salcedo; Benjamin Solish; Mona Postma; Richard Machuzak

2007-01-01

296

Model-Based Engineering of Supervisory Controllers using CIF  

Microsoft Academic Search

In the Model-Based Engineering (MBE) paradigm, models are the core elements in the design process of a system from its requirements to the actual implementation of the system. By means of Supervisory Control Theory (SCT), supervisory controllers (supervi- sors) can be synthesized instead of designing them manually. In this paper, a framework based on the Compositional Interchange Format for hybrid

Ramon R. H. Schiffelers; Rolf J. M. Theunissen; Dirk A. van Beek; Jacobus E. Rooda

2009-01-01

297

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

ERIC Educational Resources Information Center

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

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

2007-01-01

298

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

Microsoft Academic Search

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

Soyeon Shim; Antigone Kotsiopulos

1992-01-01

299

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

SciTech Connect

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

Shyam, Amit [ORNL

2007-01-01

300

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

301

A verification and validation process for model-driven engineering  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

302

Modeling Commercial Turbofan Engine Icing Risk With Ice Crystal Ingestion  

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 are 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. The PSL test has helped to calibrate the engine icing computational tool to assess the risk of ice accretion. The results from the computer simulation identified prevalent trends in wet bulb temperature, ice particle melt ratio, and engine inlet temperature as a function of altitude for predicting engine icing risk due to ice crystal ingestion.

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

2013-01-01

303

Universal Behavior of a Cyclic Oxidation Model  

NASA Technical Reports Server (NTRS)

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

Smialek, James L.

2003-01-01

304

Mathematical modelling of tissue-engineered angiogenesis  

Microsoft Academic Search

We present a mathematical model for the vascularisation of a porous scaffold following implantation in vivo. The model is given as a set of coupled non-linear ordinary differential equations (ODEs) which describe the evolution in time of the amounts of the different tissue constituents inside the scaffold. Bifurcation analyses reveal how the extent of scaffold vascularisation changes as a function

Greg Lemon; Daniel Howard; Matthew J. Tomlinson; Lee D. Buttery; Felicity R. A. J. Rose; Sarah L. Waters; John R. King

2009-01-01

305

Animal Models for Vascular Tissue-Engineering  

PubMed Central

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

Swartz, Daniel D.; Andreadis, Stelios T.

2013-01-01

306

Toward a synoptic model of gambling behavior  

Microsoft Academic Search

Most social science explanations emphasize idiosyncratic or psychopathological motivation for gambling behavior. These explanations understate the fundamental significance of conventional social structural and cultural factors in determining the meaning and outcome of human social behavior such as gambling. They also neglect the gradual process by which the individual is socialized into the gambling subculture with its roles, norms, and values

Vicki Abt; Martin C. McGurrin; James F. Smith

1985-01-01

307

Constructing Transition Models of AI Planner Behavior  

Microsoft Academic Search

Evaluation and debugging of AI systems require coherent views of program performance and behavior. We have de- veloped a family of methods, calledDependency Detection, for analyzing execution traces for small patterns. Unfortu- nately, these methods provide only a local view of program behavior. The approach described in this paper integrates two methods, dependency detection (10) and CHAID-based analysis (3), to

Adele E. Howe; Larry D. Pyeatt

1996-01-01

308

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

Microsoft Academic Search

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

Natalie Fridman; Gal A. Kaminka

2010-01-01

309

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

310

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

PubMed

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

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

2012-11-01

311

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

312

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

313

Process Definition and Project Tracking in Model Driven Engineering  

Microsoft Academic Search

This paper presents a software process definition language that is targeted towards the development of software and systems\\u000a using Model Driven Engineering methods. The dynamics of a process model are based on Petri Nets. This allows us to use a process\\u000a definition model to plan and track the execution of actual projects. This new language can be integrated with existing

Ivan Porres; María C. Valiente

2006-01-01

314

Modeling autonomous virtual agent in virtual environment for risk behavior  

Microsoft Academic Search

Owing to the complexity of human behaviors in risk situation and the harsh physical environment of underground mine, current researches on coalmine virtual environment have paid little attention on modeling human risk behaviors. Based on Artificial Life method, an intelligent virtual miner agent model was proposed to yield better understandings of human factors in emergency situation and to assist risk

Cai Linqin; Li Huijuan; Luo Zhiyong; Tang Xianlun

2010-01-01

315

A Multivariant model for single crystal shape memory alloy behavior  

Microsoft Academic Search

A general 3-D multivariant model based on thermodynamics and micromechanics for single crystal shape memory alloy (SMA) behavior is presented. This model is based on the habit plane and transformation directions for the variants of martensite in a given material. From this information, the single crystal behavior of the material to temperature and mechanical loads is derived using the concept

Miinshiou Huang; L. C. Brinson

1998-01-01

316

An integrated behavior change model for physical activity.  

PubMed

We present the Integrated Behavior Change Model, a comprehensive multitheory model outlining the psychological factors and processes that impact physical activity behavior. The model integrates hypotheses from social-cognitive, motivational, dual-phase, and dual-systems theories. We provide the theoretical basis for the model and demonstrate its utility in driving future research and developing effective interventions to promote physical activity. PMID:24508739

Hagger, Martin S; Chatzisarantis, Nikos L D

2014-04-01

317

Modified thermomechanical modeling approach for shape memory alloy behavior  

NASA Astrophysics Data System (ADS)

The Brinson-Lammering constitutive model is modified to account for the nonlinear shape memory alloy behavior. The model is divided into three modules by keeping each of the three parameters of stress, strain and temperature constant. Experiments were conducted with a NiTiCu material to obtain the model constants. The constants were then incorporated in the model and the behavior predicted. A good correlation is obtained between the theory and experiments.

Kamath, G. M.; Dayananda, G. N.; Senthilpriya, R.

2003-10-01

318

The senior high school students’ learning behavioral model of STEM in PBL  

Microsoft Academic Search

The purpose of the study was to explore a learning behavioral model of project-based learning (PBL) for senior high school\\u000a students in the context of STEM (science, technology, engineering, and mathematics). Using “audio speakers” as the project\\u000a theme, a series of tasks were designed to be solved using STEM knowledge via an online platform and student group discussions.\\u000a A total

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

2011-01-01

319

Unnotched Charpy Impact Energy Transition Behavior of Austempered Engineering Grade Ductile Iron Castings  

NASA Astrophysics Data System (ADS)

Unnotched Charpy impact energy transition behavior of five different engineering grade ductile iron castings, as specified by EN 1563 Standards, were examined in as-cast, as well as in austempered states. ADIs were produced with the maximum impact energy values permissible for the grades. Austempering treatment detrimented the sub-zero impact properties of the ferritic castings, but considerably enhanced those of the pearlitic-ferritic irons. The impact energy transition behavior of the austempered states of all the grades examined were noted to be determined by the progressive transformation of the unavoidable carbon-unsaturated and untransformed regions of the austenite remaining in the matrix of the austempered ductile iron to martensite with decreasing temperature.

Kisakurek, Sukru Ergin; Ozel, Ahmet

2014-04-01

320

Model solar flares and their homologous behavior  

NASA Astrophysics Data System (ADS)

A model describing physical processes of solar flares and their homologous behavior is presented based on resistive MHD simulations of magnetic arcade evolution subject to continuous shear-increasing footpoint motions. It is proposed in the model that the individual flaring process encompasses magnetic reconnection of arcade field lines, generation of magnetic islands in the magnetic arcade, and coalescence of magnetic islands. When a magnetic arcade is sheared, a current sheet is formed and magnetic reconnection can take place to form a magnetic island. A continuing increase of magnetic shear can trigger a new reconnection process and create another island in the underlying arcade below the magnetic island. The newborn island rises faster than the preceding island and merges with it to form one island. Before merging with the upper island is completed, the newborn island exhibits two different phases of rising motion: the first phase with a slower rising speed and the second phase with a faster rising speed. This is consistent with the Yohkoh observation by Ohyama and Shibata (1998) of X-ray plasma ejecta motion. The first phase, in which reconnection of line-tied field in the underlying arcade is important, can be regarded to be related with the preflare phase. In the second phase, the island coalescence takes place, which creates an elongated current sheet below and enhances the reconnection rate of the line-tied arcade field. This phase is interpreted as the impulsive phase or the flash phase of flares. The obtained reconnection electric field is large enough to accelerate electrons to an energy level higher than 10 keV, which is necessary for observed X-ray emissions. After merging of the islands is completed, magnetic reconnection continues in the current sheet under the integrated island for rather a long period, which can be considered as the main phase of flares. The sequence of all these processes is repeated with some time interval while a shear-increasing motion continues. The authors propose that a series of these flaring processes constitutes a set of homologous flares. The time interval between successive flaring events depends on the energy input rate into the system, which is governed by the nature of the footpoint motion and the flux reconnecting rate. They have also investigated the destruction of a magnetic island in a system undergoing a decrease of magnetic shear. The result suggests that there is a critical value of magnetic shear for existence of a magnetic island in an arcade-like field configuration.

Choe, G. S.; Cheng, C. Z.

2000-01-01

321

Structure modeling using genetically engineered crosslinking.  

PubMed

Class B G-protein-coupled receptors are exciting drug targets, yet the structure of a complete receptor bound to a peptide agonist has remained elusive. Coin et al. present a model of the receptor CRF1R bound to its native ligand based on partial structures and 44 spatial constraints revealed by new crosslinking approaches. PMID:24315089

Pal, Kuntal; Melcher, Karsten; Xu, H Eric

2013-12-01

322

Nuclear optical model calculations. Engineering technical report  

Microsoft Academic Search

The purpose of this article is to review the methods used in optical-model calculations including automatic search techniques, and to indicate how to speed up the computations while retaining desired accuracy in the results. All the formulas are presented which are required to compute the final quantities of interest i.e. the differential elastic scattering cross sections, polarizations and total reaction

M. A. Melkanoff; T. Sawada; J. Raynal

1965-01-01

323

Biomass Reburning: Modeling\\/Engineering Studies  

Microsoft Academic Search

Reburning is a mature fuel staging NOâ control technology which has been successfully demonstrated at full scale by Energy and Environmental Research Corporation (EER) and others on numerous occasions. Based on chemical kinetic modeling and experimental combustion studies, EER is currently developing novel concepts to improve the efficiency of the basic gas reburning process and to utilize various renewable and

Vladimir M. Zamansky

1998-01-01

324

Anticipatory behavior in lane changing models  

E-print Network

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

Rao, Anita (Anita Anant)

2006-01-01

325

Control-Oriented Model of a Dual Equal Variable Cam Timing Spark Ignition Engine  

E-print Network

Control-Oriented Model of a Dual Equal Variable Cam Timing Spark Ignition Engine A. G-oriented engine model is developed to represent a spark ignited engine equipped with a variable cam timing, nonlinear, low-frequency phenomenologicalengine model is developed. With respect to a xed-cam timing engine

Grizzle, Jessy W.

326

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

327

An RL10A-3-3A rocket engine model using the Rocket Engine Transient Simulator (ROCETS) software  

Microsoft Academic Search

The RL10 engine is a critical component of past, present, and future space missions. The paper discusses the RL10A-3-3A engine system and its model created using the ROCETS computer code. The simulation model will give NASA an in-house capability to simulate the performance of the engine under various operating conditions and mission profiles. A comparison of steady-state model predictions with

Michael Binder

1993-01-01

328

Building a Narrative Based Requirements Engineering Mediation Model  

NASA Astrophysics Data System (ADS)

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

Ma, Nan; Hall, Tracy; Barker, Trevor

329

Numerical Modeling of Pulse Detonation Rocket Engine Gasdynamics and Performance  

NASA Technical Reports Server (NTRS)

This paper presents viewgraphs on the numerical modeling of pulse detonation rocket engines (PDRE), with an emphasis on the Gasdynamics and performance analysis of these engines. The topics include: 1) Performance Analysis of PDREs; 2) Simplified PDRE Cycle; 3) Comparison of PDRE and Steady-State Rocket Engines (SSRE) Performance; 4) Numerical Modeling of Quasi 1-D Rocket Flows; 5) Specific PDRE Geometries Studied; 6) Time-Accurate Thrust Calculations; 7) PDRE Performance (Geometries A B C and D); 8) PDRE Blowdown Gasdynamics (Geom. A B C and D); 9) PDRE Geometry Performance Comparison; 10) PDRE Blowdown Time (Geom. A B C and D); 11) Specific SSRE Geometry Studied; 12) Effect of F-R Chemistry on SSRE Performance; 13) PDRE/SSRE Performance Comparison; 14) PDRE Performance Study; 15) Grid Resolution Study; and 16) Effect of F-R Chemistry on SSRE Exit Species Mole Fractions.

2003-01-01

330

Hera: Engineering Web Applications Using Semantic Web-based Models  

NASA Astrophysics Data System (ADS)

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

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

331

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

332

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

333

Model-driven Service Engineering with SoaML  

NASA Astrophysics Data System (ADS)

This chapter presents a model-driven service engineering (MDSE) methodology that uses OMG MDA specifications such as BMM, BPMN and SoaML to identify and specify services within a service-oriented architecture. The methodology takes advantage of business modelling practices and provides a guide to service modelling with SoaML. The presentation is case-driven and illuminated using the telecommunication example. The chapter focuses in particular on the use of the SoaML modelling language as a means for expressing service specifications that are aligned with business models and can be realized in different platform technologies.

Elvesæter, Brian; Carrez, Cyril; Mohagheghi, Parastoo; Berre, Arne-Jørgen; Johnsen, Svein G.; Solberg, Arnor

334

Genetically engineered mouse models and human osteosarcoma  

PubMed Central

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

2012-01-01

335

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

PubMed

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

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

2013-01-01

336

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

Microsoft Academic Search

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

Shaukat Ali; Lionel C. Briand; Hadi Hemmati

337

Traffic and Network Engineering in Emerging Generation IP Networks: A Bandwidth on Demand Model  

E-print Network

Traffic and Network Engineering in Emerging Generation IP Networks: A Bandwidth on Demand Model A where network engineer- ing (NE) is used to complement traffic engineering (TE) in a multi-layer setting

Krzesinski, Tony

338

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

339

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

340

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

341

PBL and CDIO: Complementary Models for Engineering Education Development  

ERIC Educational Resources Information Center

This paper compares two models for reforming engineering education, problem/project-based learning (PBL), and conceive-design-implement-operate (CDIO), identifying and explaining similarities and differences. PBL and CDIO are defined and contrasted in terms of their history, community, definitions, curriculum design, relation to disciplines,…

Edström, Kristina; Kolmos, Anette

2014-01-01

342

Modeling an engineering design application with object-oriented concepts  

E-print Network

automation. STAR implements an innovative and flexible data model that allows the user to define an object-Computer Aided Software Engineering), Manufacturing (CAM-Computer Aided Manufacturing), Office Automation, design transactions and checkin and checkout operations. In [Kat 90], Katz argued that many proposals

Wagner, Flávio Rech

343

Model-based Security Engineering with UML Jan Jurjens  

E-print Network

Model-based Security Engineering with UML Jan J¨urjens Dep. of Informatics, TU Munich, Germany Abstract. Developing security-critical systems is difficult and there are many well-known examples of security weaknesses exploited in practice. Thus a sound methodology supporting secure systems development

Jurjens, Jan

344

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

345

Multi-Project Management in Software Engineering Using Simulation Modelling  

Microsoft Academic Search

Multi-project management is crucial in Software Engineering as it draws the resources from common pools, affects the completion date of other projects, determines the priority of use of resources among various projects, involves the judgment of multi-tasking of a common resource, and eventually, determines the success or failure of the projects. Hence, this paper argues that a formal simulation model

Bengee Lee; James Miller

2004-01-01

346

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

347

Engineering&InformationTechnology Modeling and Characterization of  

E-print Network

Department 9th International Workshop on Aeroelasticity of Rotorcraft Systems October 22-24, 2001 University Outline State-of-the-art in actuator characterization Modeling and experimental results · Quasi-static and power under various load conditions #12;#5 Engineering&InformationTechnology © PRO, 2001 USC Quasi-static

Giurgiutiu, Victor

348

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

349

Modeling and Implementing Concurrent Engineering in a Virtual Collaborative Environment  

Microsoft Academic Search

Many companies are creating mterdisciplmary concurrent engineering teams to collaborate on product development projects from dispersed locations. The problems these companies face stem from the lack of understanding of technical, organizational, and pro cedural requirements for such activities to take place effectively. This paper proposes an integrated conceptual model of the product life cycle, and a virtual collaborative environment to

Ron W. E. Sky; Ralph O. Buchal

1999-01-01

350

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

351

A Process Model for Requirements Engineering of CCOTS  

Microsoft Academic Search

In this paper we present a process model for the requirements engineering of complex commercial off the shelf software (CCOTS). It describes a systematic way in which collected requirements can be brought to a concrete version plan for different products within a product system. The described process supports in particular the assessment of importance and uncertainty of possible requirement variations

Bernhard Deifel

1999-01-01

352

Model Driven Engineering versus Organic Computing, Two Complementary Approaches  

Microsoft Academic Search

Model driven engineering (MDE) and organic computing (OC) are fashion buzzwords these years. However, are the associated techniques in competition or complementary? We first provide some definitions about these terms and then present some elements suitable for discussion during the panel.

Fabrice Kordon; Marie Curie

2009-01-01

353

Model Based Systems Engineering on the Europa mission concept study  

Microsoft Academic Search

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

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

2012-01-01

354

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

355

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

356

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

Microsoft Academic Search

Models of geographical choice behavior have been dominantly based on rational choice models, which assume that decision makers\\u000a are utility-maximizers. Rational choice models may be less appropriate as behavioral models when modeling decisions in complex\\u000a environments in which decision makers may simplify the decision problem using heuristics. Pedestrian behavior in shopping\\u000a streets is an example. We therefore propose a modeling

Wei Zhu; Harry J. P. Timmermans

2011-01-01

357

The Situational Imperative: A Predictive Model of Foreign Policy Behavior  

Microsoft Academic Search

Hudson, V. M., Hermann, C. F., Singer, E. The Situational Imperative: A Predictive Model of Foreign Policy Behavior. Cooperation and Conflict, XXIV, 1989, 117-139.Foreign policy behaviors, defined in terms of the intensity of affect and commitment an actor conveys to external recipients using various instruments of statecraft, are explained in terms of a situational model. The model represents an externally-defined

Valerie M. Hudson; Charles F. Hermann; Eric Singer

1989-01-01

358

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

359

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

360

A Tool for Automatic Defect Detection in Models Used in Model-Driven Engineering  

Microsoft Academic Search

In the Model-Driven Engineering (MDE) field, the quality assurance of the involved models is fundamental for performing correct model transformations and generating final software applications. To evaluate the quality of models, defect detection is usually performed by means of reading techniques that are manually applied. Thus, new approaches to automate the defect detection in models are needed. To fulfill this

Beatriz Marín; Giovanni Giachetti; Oscar Pastor; Tanja E. J. Vos

2010-01-01

361

Ontology Modeling and Object Modeling in Software Engineering  

Microsoft Academic Search

A data model is a plan for building a database and is comparable to an architect's building plans. There are two major methodologies used to create a data model: the Entity- Relationship (ER) approach and the Object Model. This paper will be discussed only the object model approach. The goal of the data model is to certify that all data

Waralak V. Siricharoen

2009-01-01

362

Modeling Ant Behavior Under a Variable Environment  

Microsoft Academic Search

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

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

2004-01-01

363

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

364

Modeling Geographic Behavior in Riotous Crowds  

Microsoft Academic Search

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

Paul M. Torrens; Aaron W. McDaniel

2012-01-01

365

Developing robotic behavior using a genetic programming model  

SciTech Connect

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

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

1998-01-01

366

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

E-print Network

stresses. A stress-dilatancy model for sand in the cyclic loading regime, taking into account on hypoplasticity so as to accurately calculate volume changes induced by fabric and dilatancy changes during cyclic to that of solids. INTRODUCTION Most studies of cyclic behavior of sand have mainly focused on liquefaction aspects

Wan, Richard G.

367

An M3Neutral Infrastructure for Bridging Model Engineering and Ontology Engineering  

Microsoft Academic Search

In this paper we report on some research activities in the ATLAS team in Nantes and the GOOD OLD AI research group in Belgrade\\u000a in the domain of model-based engineering. We start from the idea that a convenient organization of various technical spaces\\u000a in three “metamodeling” layers offers a convenient working environment. The main message of this paper is that

Jean Bézivin; Vladan Devedzic; Dragan Djuric; Jean-Marie Favreau; Dragan Gasevic; Frederic Jouault

368

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

369

A data-driven approach to reverse engineering customer engagement models: towards functional constructs.  

PubMed

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

370

A behavior-based circuit model of how outcome expectations organize learned behavior in larval Drosophila.  

PubMed

Drosophila larvae combine a numerically simple brain, a correspondingly moderate behavioral complexity, and the availability of a rich toolbox for transgenic manipulation. This makes them attractive as a study case when trying to achieve a circuit-level understanding of behavior organization. From a series of behavioral experiments, we suggest a circuitry of chemosensory processing, odor-tastant memory trace formation, and the "decision" process to behaviorally express these memory traces--or not. The model incorporates statements about the neuronal organization of innate vs. conditioned chemosensory behavior, and the types of interaction between olfactory and gustatory pathways during the establishment as well as the behavioral expression of odor-tastant memory traces. It in particular suggests that innate olfactory behavior is responsive in nature, whereas conditioned olfactory behavior is captured better when seen as an action in pursuit of its outcome. It incorporates the available neuroanatomical and behavioral data and thus should be useful as scaffold for the ongoing investigations of the chemo-behavioral system in larval Drosophila. PMID:21946956

Schleyer, Michael; Saumweber, Timo; Nahrendorf, Wiebke; Fischer, Benjamin; von Alpen, Désirée; Pauls, Dennis; Thum, Andreas; Gerber, Bertram

2011-10-01

371

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

372

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

373

Anger in Children's Tantrums: A New, Quantitative, Behaviorally Based Model  

E-print Network

Chapter 12 Anger in Children's Tantrums: A New, Quantitative, Behaviorally Based Model Michael anger-driven behaviors in children's tantrums are probabilistic, nonlinear, and different for each Springer Science+Business Media, LLC 2010 #12;194 M. Potegal and P. Qiu anger intensity. However

Qiu, Peihua

374

Do role models influence teenagers’ purchase intentions and behavior?  

Microsoft Academic Search

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

Craig A. Martin; Alan J. Bush

2000-01-01

375

Stream Processing Algorithms that Model Behavior Agostino Capponi Mani Chandy  

E-print Network

conditions; patterns of incidence of disease change at the onset of pandemics; file access pat- terns change from proper usage to improper use that may signify insider threat. The models that repre- sent behavior behaviors vary over time; for example, an informa- tion network varies from heavily loaded to lightly loaded

376

Toward a Theory of Intelligent Behavior: A Proposed Model  

ERIC Educational Resources Information Center

A dyadic model shows intelligent behavior as result of invariant processes of (a) organism-environmental reaction, (b) experience acquisition involving internal organism transformation, and (c) development of central processes of control. If interaction is controlled subsequent observed behaviors should clarify classroom role of psychologist.…

Rowland, Thomas; McGuire, Carson

1968-01-01

377

Modeling the Antecedents of Proactive Behavior at Work  

Microsoft Academic Search

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

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

2006-01-01

378

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

ERIC Educational Resources Information Center

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

Sirbu, Marvin A., Jr.

1979-01-01

379

A comparative study of oral health attitudes and behavior using the Hiroshima University-Dental Behavioral Inventory (HU-DBI) between dental and civil engineering students in Colombia.  

PubMed

The aim of this study was to use the Hiroshima University - Dental Behavioral Inventory (HU-DBI) to compare oral health attitudes and behavior of dental and civil engineering students in Colombia. The HU-DBI's survey consisting of twenty dichotomous responses (agree-disagree) regarding tooth brushing, was completed at University Antonio Narino for the dental students and the University of Cauca for the civil engineering students. The Spanish version of the HU-DBI questionnaire was taken by 182 of 247 dental students and 411 of 762 engineering students. The data was-statistically analyzed by the chi-square test and backward logistic regression. Compared to the engineering students, the dental students were more likely to agree with questions such as "I am bothered by the color of my gums"(OR = 2.2, 95% CI: 1.3-3.7),"I think I can clean my teeth well without using toothpaste" (OR = 3.0, 95% CI: 1.5-5.9), "I have used a dye to see how clean my teeth are" (OR = 2.9, 95% CI: 1.9-4.3), and "I have had my dentist tell me that I brush very well" (OR = 2.0, 95% CI: 1.3-3.1). The dental education curriculum in a dental school compared to a civil engineering school in Colombia indicated that a three-phase curriculum in didactics and clinics increased oral health attitudes and behavior from entry to graduation. PMID:23485597

Jaramillo, Jorge A; Jaramillo, Fredy; Kador, Itzjak; Masuoka, David; Tong, Liyue; Ahn, Chul; Komabayashi, Takashi

2013-03-01

380

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

Microsoft Academic Search

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

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

2009-01-01

381

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

382

Behavior modeling through CHAOS for simulation of dismounted soldier operations  

NASA Astrophysics Data System (ADS)

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

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

2008-04-01

383

Critical behavior of the Widom--Rowlinson lattice model  

SciTech Connect

We report extensive Monte Carlo simulations of the Widom--Rowlinson lattice model in two and three dimensions. Our results yield precise values for the critical activities and densities, and clearly place the critical behavior in the Ising universality class.

Dickman, R. [Department of Physics and Astronomy, Lehman College, CUNY, Bronx, New York 10468-1589 (United States)] [Department of Physics and Astronomy, Lehman College, CUNY, Bronx, New York 10468-1589 (United States); Stell, G. [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400 (United States)] [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400 (United States)

1995-06-01

384

Some considerations for modeling the creep behavior of composite materials  

SciTech Connect

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

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

1994-05-01

385

Data-driven models for uncertainty and behavior  

E-print Network

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

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

2014-01-01

386

A simple generative model of collective online behavior.  

PubMed

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

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

2014-07-22

387

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

388

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

389

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

390

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

391

Mathematical Models and the Experimental Analysis of Behavior  

ERIC Educational Resources Information Center

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

Mazur, James E.

2006-01-01

392

Behavioral modeling of IC output buffers: a case study  

Microsoft Academic Search

This paper addresses the behavioral modeling of IC output ports by means of nonlinear parametric relations and system identification methods. The approach is applied to a com- mercial device and a systematic discussion of the impact of the modeling setup on the model performance is presented.

C. Siviero; I. S. Stievano; I. A. Maio

2005-01-01

393

Long Term Oxidation of Model and Engineering TiAl Alloys  

SciTech Connect

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

Locci, IE

2001-08-24

394

Modeling and simulating human teamwork behaviors using intelligent agents  

NASA Astrophysics Data System (ADS)

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

Fan, Xiaocong; Yen, John

2004-12-01

395

Engineering models for catastrophe risk and their application to insurance  

NASA Astrophysics Data System (ADS)

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

Dong, Weimin

2002-06-01

396

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

SciTech Connect

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

Burns, B.A.

1980-11-01

397

Network Engineering of Elastic Data Tra#c via Tandem Queueing Network Models  

E-print Network

Network Engineering of Elastic Data Tra#c via Tandem Queueing Network Models A. W. Berger 1 , E. G is long­range dependent. The tandem CQN models are motivated by the following network engineering scenario

Coffman Jr., E. G.

398

Modeling of the fracture behavior of spot welds using advanced micro-mechanical damage models  

NASA Astrophysics Data System (ADS)

This paper presents the modeling of deformation and fracture behavior of resistance spot welded joints in DP600 steel sheets. Spot welding is still the most commonly used joining technique in automotive engineering. In overloading situations like crash joints are often the weakest link in a structure. For those reasons, crash simulations need reliable and applicable tools to predict the load bearing capacity of spot welded components. Two series of component tests with different spot weld diameters have shown that the diameter of the weld nugget is the main influencing factor affecting fracture mode (interfacial or pull-out fracture), load bearing capacity and energy absorption. In order to find a correlation between nugget diameter, load bearing capacity and fracture mode, the spot welds are simulated with detailed finite element models containing base metal, heat affected zone and weld metal in lap-shear loading conditions. The change in fracture mode from interfacial to pull-out or peel-out fracture with growing nugget diameter under lap-shear loading was successfully modeled using the Gologanu-Leblond model in combination with the fracture criteria of Thomason and Embury. A small nugget diameter is identified to be the main cause for interfacial fracture. In good agreement with experimental observations, the calculated pull-out fracture initiates in the base metal at the boundary to the heat affected zone.

Sommer, Silke

2010-06-01

399

Model-based engineering for laser weapons systems  

Microsoft Academic Search

The Comet Performance Engineering Workspace is an environment that enables integrated, multidisciplinary modeling and design\\/simulation process automation. One of the many multi-disciplinary applications of the Comet Workspace is for the integrated Structural, Thermal, Optical Performance (STOP) analysis of complex, multi-disciplinary space systems containing Electro-Optical (EO) sensors such as those which are designed and developed by and for NASA and the

Malcolm Panthaki; Steve Coy

2011-01-01

400

A sensitive ALMA Band 10 SIS receiver engineering model  

Microsoft Academic Search

We have developed a single polarization engineering model of the Atacama Large Millimeter\\/Submillimeter Array (ALMA) Band 10 (0.78-0.95 THz) receivers. The front-end optics comprises a pair of ellipsoidal mirrors and a corrugated feed horn. A waveguide mixer block is attached to the feed horn in which an NbTiN-based superconductor-insulator-superconductor (SIS) mixer chip, which uses a quartz substrate, is mounted onto

Y. Uzawa; M. Kroug; T. Kojima; M. Takeda; M. Candotti; Y. Fujii; K. Kaneko; W. Shan; T. Noguchi; Z. Wang

2009-01-01

401

A Reference Model for Factory Engineering and Design  

Microsoft Academic Search

Today factories can be considered as products, which contribute to value creation by efficient transformation of resources\\u000a into high-adding value products and which have to be continuously adapted. The engineering of future factories requires digital\\u000a tools to support the life cycle phases from investment planning to ramp-up and scientific-based integrated highly-dynamic\\u000a data management systems. This paper presents a Reference Model

Carmen Constantinescu; Engelbert Westkämper

402

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

403

Improved engine wall models for Large Eddy Simulation (LES)  

NASA Astrophysics Data System (ADS)

Improved wall models for Large Eddy Simulation (LES) are presented in this research. The classical Werner-Wengle (WW) wall shear stress model is used along with near-wall sub-grid scale viscosity. A sub-grid scale turbulent kinetic energy is employed in a model for the eddy viscosity. To gain better heat flux results, a modified classical variable-density wall heat transfer model is also used. Because no experimental wall shear stress results are available in engines, the fully turbulent developed flow in a square duct is chosen to validate the new wall models. The model constants in the new wall models are set to 0.01 and 0.8, respectively and are kept constant throughout the investigation. The resulting time- and spatially-averaged velocity and temperature wall functions from the new wall models match well with the law-of-the-wall experimental data at Re = 50,000. In order to study the effect of hot air impinging walls, jet impingement on a flat plate is also tested with the new wall models. The jet Reynolds number is equal to 21,000 and a fixed jet-to-plate spacing of H/D = 2.0. As predicted by the new wall models, the time-averaged skin friction coefficient agrees well with experimental data, while the computed Nusselt number agrees fairly well when r/D > 2.0. Additionally, the model is validated using experimental data from a Caterpillar engine operated with conventional diesel combustion. Sixteen different operating engine conditions are simulated. The majority of the predicted heat flux results from each thermocouple location follow similar trends when compared with experimental data. The magnitude of peak heat fluxes as predicted by the new wall models is in the range of typical measured values in diesel combustion, while most heat flux results from previous LES wall models are over-predicted. The new wall models generate more accurate predictions and agree better with experimental data.

Plengsaard, Chalearmpol

404

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

405

Model Engine Performance Measurement From Force Balance Instrumentation  

NASA Technical Reports Server (NTRS)

A large scale model representative of a low-noise, high bypass ratio turbofan engine was tested for acoustics and performance in the NASA Lewis 9- by 15-Foot Low-Speed Wind Tunnel. This test was part of NASA's continuing Advanced Subsonic Technology Noise Reduction Program. The low tip speed fan, nacelle, and an un-powered core passage (with core inlet guide vanes) were simulated. The fan blades and hub are mounted on a rotating thrust and torque balance. The nacelle, bypass duct stators, and core passage are attached to a six component force balance. The two balance forces, when corrected for internal pressure tares, measure the total thrust-minus-drag of the engine simulator. Corrected for scaling and other effects, it is basically the same force that the engine supports would feel, operating at similar conditions. A control volume is shown and discussed, identifying the various force components of the engine simulator thrust and definitions of net thrust. Several wind tunnel runs with nearly the same hardware installed are compared, to identify the repeatability of the measured thrust-minus-drag. Other wind tunnel runs, with hardware changes that affected fan performance, are compared to the baseline configuration, and the thrust and torque effects are shown. Finally, a thrust comparison between the force balance and nozzle gross thrust methods is shown, and both yield very similar results.

Jeracki, Robert J.

1998-01-01

406

A capillary network model for gas migration in engineered barriers  

SciTech Connect

Gas may be generated in a waste repository by a number of mechanisms, including anaerobic corrosion of metals and microbial degradation. Scoping calculations indicate that a free gas phase will probably form. Here attention is focused on two hazards this may pose. First, a gas pressure buildup may damage engineered barriers. Second, migrating gas may displace contaminated pore water. In previous studies, Darcy two-phase flow models have been used to calculate gas pressures and pore water displacement. A two-dimensional capillary network model has been developed and implemented in a numerical code, GARNET. Example calculations of the migration of gas from a point source have been undertaken to demonstrate its functionality and to indicate how phenomena, such as intermittent gas fluxes, may be modelled. Results indicate that the capillary network model reproduces behaviour observed in gas migration through low permeability media, and is a viable alternative to Darcy two-phase flow models.

Impey, M.D.; Grindrod, P.; Worgan, K.J. [Intera Information Technologies, Oxon (United Kingdom)] [and others

1995-12-01

407

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

Federal Register 2010, 2011, 2012, 2013

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

2011-05-05

408

Towards Modeling HIV Long Term Behavior  

E-print Network

The precise mechanism that causes HIV infection to progress to AIDS is still unknown. This paper presents a mathematical model which is able to predict the entire trajectory of the HIV/AIDS dynamics, then a possible explanation for this progression is examined. A dynamical analysis of this model reveals a set of parameters which may produce two real equilibria in the model. One equilibrium is stable and represents those individuals who have been living with HIV for at least 7 to 9 years, and do not develop AIDS. The other one is unstable and represents those patients who developed AIDS in an average period of 10 years. However, further work is needed since the proposed model is sensitive to parameter variations.

Hernandez-Vargas, Esteban A; Middleton, Richard H

2011-01-01

409

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

Microsoft Academic Search

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

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

410

Quality Issues on Model-Driven Web Engineering Methodologies  

NASA Astrophysics Data System (ADS)

Nowadays, there are several development methodologies in the field of model-driven web engineering (MDWE) which involve different levels of model-driven architecture (MDA): CIM, PIM, PSM, or code. Attending to the high number of available methodologies, development teams may feel lost when choosing the most suitable one for their projects. Furthermore, proposals usually appear and people feel necessary to evaluate their quality in order to select the appropriate methodology or even to find out the way to improve them. This chapter presents the current work carried out in this field and it is oriented toward the definition of a framework which enables an objective measurement of the proposals' benefits.

Domínguez-Mayo, F. J.; Escalona, M. J.; Mejías, M.

411

Model-Driven Engineering of Machine Executable Code  

NASA Astrophysics Data System (ADS)

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

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

412

A Reflective Approach to Model-Driven Web Engineering  

NASA Astrophysics Data System (ADS)

A reflective approach to model-driven web engineering is presented, which aims to overcome several of the shortcomings of existing generative approaches. The approach uses the Epsilon platform and Apache Tomcat to render dynamic HTML content using Epsilon Generation Language templates. This enables EMF-based models to be used as data sources without the need to pre-generate any HTML or dynamic script, or duplicate the contents into a database. The paper reports on our experimental results in using this approach for dynamically querying and visualising a very large military standard.

Clowes, Darren; Kolovos, Dimitris; Holmes, Chris; Rose, Louis; Paige, Richard; Johnson, Julian; Dawson, Ray; Probets, Steve

413

Ethical issues in engineering models: an operations researcher's reflections.  

PubMed

This article starts with an overview of the author's personal involvement--as an Operations Research consultant--in several engineering case-studies that may raise ethical questions; e.g., case-studies on nuclear waste, water management, sustainable ecology, military tactics, and animal welfare. All these case studies employ computer simulation models. In general, models are meant to solve practical problems, which may have ethical implications for the various stakeholders; namely, the modelers, the clients, and the public at large. The article further presents an overview of codes of ethics in a variety of disciples. It discusses the role of mathematical models, focusing on the validation of these models' assumptions. Documentation of these model assumptions needs special attention. Some ethical norms and values may be quantified through the model's multiple performance measures, which might be optimized. The uncertainty about the validity of the model leads to risk or uncertainty analysis and to a search for robust models. Ethical questions may be pressing in military models, including war games. However, computer games and the related experimental economics may also provide a special tool to study ethical issues. Finally, the article briefly discusses whistleblowing. Its many references to publications and websites enable further study of ethical issues in modeling. PMID:20535643

Kleijnen, J

2011-09-01

414

Axisymmetric Numerical Modeling of Pulse Detonation Rocket Engines  

NASA Technical Reports Server (NTRS)

Pulse detonation rocket engines (PDREs) have generated research interest in recent years as a chemical propulsion system potentially offering improved performance and reduced complexity compared to conventional rocket engines. The detonative mode of combustion employed by these devices offers a thermodynamic advantage over the constant-pressure deflagrative combustion mode used in conventional rocket engines and gas turbines. However, while this theoretical advantage has spurred considerable interest in building PDRE devices, the unsteady blowdown process intrinsic to the PDRE has made realistic estimates of the actual propulsive performance problematic. The recent review article by Kailasanath highlights some of the progress that has been made in comparing the available experimental measurements with analytical and numerical models. In recent work by the author, a quasi-one-dimensional, finite rate chemistry CFD model was utilized to study the gasdynamics and performance characteristics of PDREs over a range of blowdown pressure ratios from 1-1000. Models of this type are computationally inexpensive, and enable first-order parametric studies of the effect of several nozzle and extension geometries on PDRE performance over a wide range of conditions. However, the quasi-one-dimensional approach is limited in that it cannot properly capture the multidimensional blast wave and flow expansion downstream of the PDRE, nor can it resolve nozzle flow separation if present. Moreover, the previous work was limited to single-pulse calculations. In this paper, an axisymmetric finite rate chemistry model is described and utilized to study these issues in greater detail. Example Mach number contour plots showing the multidimensional blast wave and nozzle exhaust plume are shown. The performance results are compared with the quasi-one-dimensional results from the previous paper. Both Euler and Navier-Stokes solutions are calculated in order to determine the effect of viscous effects in the nozzle flowfield. Additionally, comparisons of the model results to performance data from CalTech, as well as experimental flowfield measurements from Stanford University, are also reported.

Morris, Christopher I.

2005-01-01

415

Crossover behavior of conductivity in a discontinuous percolation model  

NASA Astrophysics Data System (ADS)

When conducting bonds are occupied randomly in a two-dimensional square lattice, the conductivity of the system increases continuously as the density of those conducting bonds exceeds the percolation threshold. Such a behavior is well known in percolation theory; however, the conductivity behavior has not been studied yet when the percolation transition is discontinuous. Here we investigate the conductivity behavior through a discontinuous percolation model evolving under a suppressive external bias. Using effective medium theory, we analytically calculate the conductivity behavior as a function of the density of conducting bonds. The conductivity function exhibits a crossover behavior from a drastically to a smoothly increasing function beyond the percolation threshold in the thermodynamic limit. The analytic expression fits well our simulation data.

Kim, Seongmin; Cho, Y. S.; Araújo, N. A. M.; Kahng, B.

2014-03-01

416

Model-based engineering for laser weapons systems  

NASA Astrophysics Data System (ADS)

The Comet Performance Engineering Workspace is an environment that enables integrated, multidisciplinary modeling and design/simulation process automation. One of the many multi-disciplinary applications of the Comet Workspace is for the integrated Structural, Thermal, Optical Performance (STOP) analysis of complex, multi-disciplinary space systems containing Electro-Optical (EO) sensors such as those which are designed and developed by and for NASA and the Department of Defense. The CometTM software is currently able to integrate performance simulation data and processes from a wide range of 3-D CAD and analysis software programs including CODE VTM from Optical Research Associates and SigFitTM from Sigmadyne Inc. which are used to simulate the optics performance of EO sensor systems in space-borne applications. Over the past year, Comet Solutions has been working with MZA Associates of Albuquerque, NM, under a contract with the Air Force Research Laboratories. This funded effort is a "risk reduction effort", to help determine whether the combination of Comet and WaveTrainTM, a wave optics systems engineering analysis environment developed and maintained by MZA Associates and used by the Air Force Research Laboratory, will result in an effective Model-Based Engineering (MBE) environment for the analysis and design of laser weapons systems. This paper will review the results of this effort and future steps.

Panthaki, Malcolm; Coy, Steve

2011-10-01

417

Neutronics Behavior Comparison Using Different Thermohydraulic Modelizations  

SciTech Connect

The results of testing the three-dimensional (3-D) and point neutron kinetics response with imposed thermohydraulic boundary conditions using TRAC/BF1, TRAC/PF1, and RETRAN-3D are reported. Four different reactor core models were developed. The results of the neutronic power for the four models using point kinetics are shown. It was found that the 3-D thermohydraulics can be modeled by n independent channels associated with different sectors of the vessel. The other conclusion was that the effects of the core cross-flow and the lower plenum mixing are not important; this finding confirms the adequacy of the 1-D thermal-hydraulics/3-D neutronic codes like RETRAN-3D to simulate these kinds of plant transients.

Verdu, G.; Rosello, O.; Gomez, A.

2001-06-17

418

Electric power industry: an econometric model of intertemporal behavior  

SciTech Connect

An intertemporal model of producer behavior is a more-appropriate set of standards for evaluating utilities' input choices against the efficiency conditions than models maintaining long-run equilibrium behavior at each point in time. Observed input choices should be evaluated against a planning horizon determined by economic conditions over a period of years. The long economic lives of capital assets are explicitly recognized in a multiperiod econometric model. Investment decisions are functions of present and future prices and regulatory conditions. There is no evidence of input distortion. 29 references.

Gollop, F.M. (Boston College, MA); Karlson, S.H.

1980-08-01

419

A BEHAVIORAL AVERAGE MODEL OF SEPIC CONVERTERS WITH COUPLED INDUCTORS  

E-print Network

1 A BEHAVIORAL AVERAGE MODEL OF SEPIC CONVERTERS WITH COUPLED INDUCTORS D. Adar, G. Rahav and S@bguee.bgu.ac.il Abstract An average model of SEPIC converters with coupled inductors was developed and verified against state (DC), large signal (Transient) and small signal (AC) analyses. The inductors coupling coefficient

420

Fractal rheological models and fractional differential equations for viscoelastic behavior  

Microsoft Academic Search

A constitutive equation for viscoelastic behavior containing time derivatives of stress and strain to fractional order is obtained from a fractal rheological model. Equivalence between tree and ladder fractal models at long times is demonstrated. The fractional differential equation is shown to be equivalent to ordinary differential formulations in the case of a simple power-law response; the adequacy of such

Nicole Heymans; J.-C. Bauwens

1994-01-01

421

Thermodynamic modeling of precipitation behavior in mixed micellar systems  

Microsoft Academic Search

Results of thermodynamic modeling of solubility diagrams for various types of mixed micellar systems (nonionic surfactants with added alkanols, mixtures of two nonionics, two anionics, anionic plus semipolar surfactants) are summarized. Phase behavior over a wide range of surfactant concentrations is under study and the model description is aimed at prediction of the solubility diagrams in ternary systems on the

N. A. Smirnova

2001-01-01

422

Modeling SRAM Start-Up Behavior for Physical Unclonable Functions  

E-print Network

Modeling SRAM Start-Up Behavior for Physical Unclonable Functions Mafalda Cortez Apurva Dargar Said-submicron process variations. SRAM PUF is an example of such technology that is becoming popular. So far, only. This paper presents an analytical model for SUVs of an SRAM PUF based on Static Noise Margin (SNM

Kuzmanov, Georgi

423

A Model of Solar Flares and Their Homologous Behavior  

Microsoft Academic Search

A model describing physical processes of solar flares and their homologous behavior is presented based on resistive MHD simulations of magnetic arcade evolution subject to continuous shear-increasing footpoint motions. It is proposed in our model that the individual flaring process encompasses magnetic reconnection of arcade field lines, generation of magnetic islands in the magnetic arcade, and coalescence of magnetic islands.

G. S. Choe; C. Z. Cheng

2000-01-01

424

Modeling and simulation of the dynamic behavior of monoliths  

Microsoft Academic Search

A mathematical model is presented that could be used to describe the dynamic behavior, scale-up, and design of monoliths involving the adsorption of a solute of interest. The value of the pore diffusivity of the solute in the pores of the skeletons of the monolith is determined in an a priori manner by employing the pore network modeling theory of

A. I Liapis; J. J Meyers; O. K Crosser

1999-01-01

425

MULTISCALE MODELING OF THE THERMOVISCOPLASTIC BEHAVIOR OF METAL MATRIX COMPOSITES  

Microsoft Academic Search

Summary. This paper deals with the thermoviscoplastic behavior of metal matrix com- posites. A constitutive model, based on Dvorak's Transformation Field Analysis, is im- plemented to investigate the response of an Al\\/Al203 composite under an anisothermal, cyclic loading. The experimental validation of the model and its implementation in the finite element code ABAQUS through a user defined material (UMAT) subroutine

Benoit Berini; Myriam Bourgeois; Djaar Boussaa; Pierre Suquet; Jean-Jacques Thomas

426

Effects of Video Modeling on Treatment Integrity of Behavioral Interventions  

ERIC Educational Resources Information Center

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…

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

2010-01-01

427

Toward a Self-Evaluation Maintenance Model of Social Behavior.  

ERIC Educational Resources Information Center

This paper describes the Self-Evaluation Maintenance (SEM) model of social behavior which consists of three variables: the psychological closeness of another, the relative performance of that other, and the relevance of the performance dimension to one's self-definition. The SEM model is described as involving two processes, the reflection process…

Tesser, Abraham

428

Modeling and simulating human teamwork behaviors using intelligent agents  

Microsoft Academic Search

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

Xiaocong Fan; John Yen

2004-01-01

429

A Neurobehavioral Model of Flexible Spatial Language Behaviors  

ERIC Educational Resources Information Center

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

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

2012-01-01

430

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

431

Modeling and cold start in alcohol-fueled engines  

SciTech Connect

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

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

1998-05-01

432

Subject: [roboms] [jobs] Motion Behavior Engineer & Software Developer Date: Tue, 16 Jun 2009 17:47:15 0400  

E-print Network

* > > > > Our Client is looking for a versatile programmer to create and tune > lowerlevel character behaviors. > * Ability to work with other programmers, animators and design to > make sure they can get the most's degree in Computer Science, Software Engineering, > Physics or equivalent work experience

Plotkin, Joshua B.

433

A Study on Microblog and Search Engine User Behaviors: How Twitter Trending Topics Help Predict Google Hot Queries  

E-print Network

A Study on Microblog and Search Engine User Behaviors: How Twitter Trending Topics Help Predict Ca' Foscari Venezia, Italy Email: gabriele.tolomei@unive.it ABSTRACT Once every five minutes, Twitter that social trends fired by Twitter may help explain and predict web trends derived from Google. Indeed, we

Orlando, Salvatore

434

Engine structures modeling software system: Computer code. User's manual  

NASA Astrophysics Data System (ADS)

ESMOSS is a specialized software system for the construction of geometric descriptive and discrete analytical models of engine parts, components and substructures which can be transferred to finite element analysis programs such as NASTRAN. The software architecture of ESMOSS is designed in modular form with a central executive module through which the user controls and directs the development of the analytical model. Modules consist of a geometric shape generator, a library of discretization procedures, interfacing modules to join both geometric and discrete models, a deck generator to produce input for NASTRAN and a 'recipe' processor which generates geometric models from parametric definitions. ESMOSS can be executed both in interactive and batch modes. Interactive mode is considered to be the default mode and that mode will be assumed in the discussion in this document unless stated otherwise.

1992-04-01

435

Quantitative Modeling of Polymer Scratch Behavior  

E-print Network

investigated experimentally by employing the ASTM D7027-05 standard scratch test on four model thermoplastic olefin (TPO) systems, with and without slip agent and talc fillers [36]. Through the standard scratch test and microscopy, it was shown that a...

Hossain, Mohammad Motaher

2013-12-02

436

Behavioral models of frequency pulling in oscillators  

Microsoft Academic Search

Based on the state equations of an RLC circuit and hard-limiting characteristics of a transconductor a method is introduced to study and simulate the pulling effect in differential LC oscillators. This method includes phase and amplitude disturbances all at once. The model is validated by measurement results and an example is given to illustrate the application of this method in

M. Esmaeil Heidari; A. A. Abidi

2007-01-01

437

Instrumental Conditioning IV: modeling free operant behavior  

E-print Network

dopamine: reward prediction error · but also another mode of dopamine signaling: tonic dopamine 12 moreless #12;tonic dopamine hypothesis 13 tonic level of dopamine = average reward rate Aberman and Salamone 1000 1200 Model simulation #LPsin30minutes Control DA depleted tonic dopamine hypothesis 14

Niv, Yael

438

A Simple Model of Herd Behavior  

Microsoft Academic Search

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

Abhijit V Banerjee

1992-01-01

439

Crowd behavior dynamics: entropic path-integral model  

Microsoft Academic Search

We propose an entropic geometrical model of crowd behavior dynamics (with dissipative crowd kinematics), using Feynman action-amplitude\\u000a formalism that operates on three synergetic levels: macro, meso, and micro. The intent is to explain the dynamics of crowds\\u000a simultaneously and consistently across these three levels, in order to characterize their geometrical properties particularly\\u000a with respect to behavior regimes and the state

Vladimir G. Ivancevic; Darryn J. Reid; Eugene V. Aidman

2010-01-01

440

Econometric modeling of industries: Semiconductors and internal-combustion engines  

SciTech Connect

A small-scale econometric model of an industry is developed as a tool to analyze the impact of government purchases and other exogenous variables on the output, capital expenditures, and employment of the semiconductor industry in the United States. The model is also applied to the internal-combustion-engine industry in order to examine its performance on an alternative industry. The model consists of an equation for the industry's output, an investment and a man hour equation for the industry's input, and an equation for the shipments of the industries that use the industry's outputs as an intermediate input. An historical simulation is conducted for both industries on a microcomputer to test the accuracy of the model over the estimation periods. Results indicate that government defense purchases have significant impact on the information industries, which in turn influence the semiconductor industry. Government defense purchases, however, do not show any significant effect on the shipments of the primary purchasers of the internal-combustion engines.

Torbat-Esfahani, A.

1987-01-01

441

Accelerating cancer modeling with RNAi and nongermline genetically engineered mouse models.  

PubMed

For more than two decades, genetically engineered mouse models have been key to our mechanistic understanding of tumorigenesis and cancer progression. Recently, the massive quantity of data emerging from cancer genomics studies has demanded a corresponding increase in the efficiency and throughput of in vivo models for functional testing of putative cancer genes. Already a mainstay of cancer research, recent innovations in RNA interference (RNAi) technology have extended its utility for studying gene function and genetic interactions, enabling tissue-specific, inducible and reversible gene silencing in vivo. Concurrent advances in embryonic stem cell (ESC) culture and genome engineering have accelerated several steps of genetically engineered mouse model production and have facilitated the incorporation of RNAi technology into these models. Here, we review the current state of these technologies and examine how their integration has the potential to dramatically enhance the throughput and capabilities of animal models for cancer. PMID:24184755

Livshits, Geulah; Lowe, Scott W

2013-11-01

442

Accelerating Cancer Modeling with RNAi and Nongermline Genetically Engineered Mouse Models  

PubMed Central

For more than two decades, genetically engineered mouse models have been key to our mechanistic understanding of tumorigenesis and cancer progression. Recently, the massive quantity of data emerging from cancer genomics studies has demanded a corresponding increase in the efficiency and throughput of in vivo models for functional testing of putative cancer genes. Already a mainstay of cancer research, recent innovations in RNA interference (RNAi) technology have extended its utility for studying gene function and genetic interactions, enabling tissue-specific, inducible and reversible gene silencing in vivo. Concurrent advances in embryonic stem cell (ESC) culture and genome engineering have accelerated several steps of genetically engineered mouse model production and have facilitated the incorporation of RNAi technology into these models. Here, we review the current state of these technologies and examine how their integration has the potential to dramatically enhance the throughput and capabilities of animal models for cancer. PMID:24184755

Livshits, Geulah; Lowe, Scott W.

2014-01-01

443

The Global Engineering College: exploring a new model for engineering education in a global economy  

Microsoft Academic Search

ABSTRACT The increasing globalization of corporate economies,has changed the face of engineering practice. In addition to core engineering skills, modern engineers must possess cross-cultural communication skills, team management skills, and the ability to perform on geographically distributed teams. We describe a novel curricular paradigm called the Global Engineering College (GEC) that we are currently exploring under an NSF planning grant.

Eckehard Doerry; Karl Doerry; Bridget Bero

444

Modeling emergent border-crossing behaviors during pandemics  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

445

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

446

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

447

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

448

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

449

Model-Based Systems Engineering Pilot Program at NASA Langley  

NASA Technical Reports Server (NTRS)

NASA Langley Research Center conducted a pilot program to evaluate the benefits of using a Model-Based Systems Engineering (MBSE) approach during the early phase of the Materials International Space Station Experiment-X (MISSE-X) project. The goal of the pilot was to leverage MBSE tools and methods, including the Systems Modeling Language (SysML), to understand the net gain of utilizing this approach on a moderate size flight project. The System Requirements Review (SRR) success criteria were used to guide the work products desired from the pilot. This paper discusses the pilot project implementation, provides SysML model examples, identifies lessons learned, and describes plans for further use on MBSE on MISSE-X.

Vipavetz, Kevin G.; Murphy, Douglas G.; Infeld, Samatha I.

2012-01-01

450

Human Factors Engineering Review Model for advanced nuclear power reactors  

SciTech Connect

One of the major issues to emerge from the initial design reviews under the certification process was that detailed human-systems interface (HSI) design information was not available for staff review. To address the lack of design detail issue. The Nuclear Regulatory Commission (NRC) is performing the design certification reviews based on a design process plan which describes the human factors engineering (HFE) program elements that are necessary and sufficient to develop an acceptable detailed design specification. Since the review of a design process is unprecedented in the nuclear industry. The criteria for review are not addressed by current regulations or guidance documents and. therefore, had to be developed. Thus, an HFE Program Review Model was developed. This paper will describe the model`s rationale, scope, objectives, development, general characteristics. and application.

O`Hara, J.; Higgins, J. [Brookhaven National Lab., Upton, NY (United States); Goodman, C.; Galletti, G.: Eckenrode, R. [Nuclear Regulatory Commission, Rockville, MD (United States)

1993-05-01

451

Comparison of Engineering Wake Models with CFD Simulations  

NASA Astrophysics Data System (ADS)

The engineering wake models by Jensen [1] and Frandsen et al. [2] are assessed for different scenarios simulated using Large Eddy Simulation and the Actuator Line method implemented in the Navier-Stokes equations. The scenarios include the far wake behind a single wind turbine, a long row of turbines in an atmospheric boundary layer, idealised cases of an infinitely long row of wind turbines and infinite wind farms with three different spacings. Both models include a wake expansion factor, which is calibrated to fit the simulated wake velocities. The analysis highlights physical deficiencies in the ability of the models to universally predict the wake velocities, as the expansion factor can be fitted for a given case, but with not apparent transition between the cases.

Andersen, S. J.; Sørensen, J. N.; Ivanell, S.; Mikkelsen, R. F.

2014-06-01

452

A mathematical model for jet engine combustor pollutant emissions  

NASA Technical Reports Server (NTRS)

Mathematical modeling for the description of the origin and disposition of combustion-generated pollutants in gas turbines is presented. A unified model in modular form is proposed which includes kinetics, recirculation, turbulent mixing, multiphase flow effects, swirl and secondary air injection. Subelements of the overall model were applied to data relevant to laboratory reactors and practical combustor configurations. Comparisons between the theory and available data show excellent agreement for basic CO/H2/Air chemical systems. For hydrocarbons the trends are predicted well including higher-than-equilibrium NO levels within the fuel rich regime. Although the need for improved accuracy in fuel rich combustion is indicated, comparisons with actual jet engine data in terms of the effect of combustor-inlet temperature is excellent. In addition, excellent agreement with data is obtained regarding reduced NO emissions with water droplet and steam injection.

Boccio, J. L.; Weilerstein, G.; Edelman, R. B.

1973-01-01

453

Ecological Modelling 140 (2001) 18 Integrating ecology with human demography, behavior, and  

E-print Network

Ecological Modelling 140 (2001) 1­8 Integrating ecology with human demography, behavior an urgent need to integrate ecology with human demography, behavior, and socioeconomics in order; Human demography; Human behavior; Sociology; Economics; Modeling; Simulation. www

454

Modeling Information Needs in Engineering Databases Using Tacit Knowledge  

Microsoft Academic Search

Online resources of engineering design information are a critical resource for practicing engineers. These online resources often contain references and content associated with technical memos, journal articles and \\

Shuang Song; Andy Dong; Alice M. Agogino

2002-01-01

455

Behavioral and computational models of spatial attention.  

PubMed

Pigeons pecked for food in a spatially cued choice reaction time (RT) task. A brief (50-ms) white light appeared on a left or right key and probabilistically predicted the location (on either the left or right key) of a subsequent target stimulus. The time between cue and target onset (stimulus onset asynchrony), the base rate of left cues, and the probability that the cue correctly predicted the target (cue validity) were experimentally varied. The mean RT to respond to the target key was faster on correctly cued trials (defining a validity effect), decreased for both valid and invalid trials as stimulus onset asynchrony increased (defining an alerting effect), showed a variety of base-rate effects, and did not depend on cue validity. It is shown with a computational-processing model that dynamic interactions of short-term and associative memory processes are sufficient to produce these attentionlike empirical phenomena. PMID:8418214

Shimp, C P; Friedrich, F J

1993-01-01

456

Software Engineering Laboratory (SEL) relationships, models, and management rules  

NASA Technical Reports Server (NTRS)

Over 50 individual Software Engineering Laboratory (SEL) research results, extracted from a review of published SEL documentation, that can be applied directly to managing software development projects are captured. Four basic categories of results are defined and discussed - environment profiles, relationships, models, and management rules. In each category, research results are presented as a single page that summarizes the individual result, lists potential uses of the result by managers, and references the original SEL documentation where the result was found. The document serves as a concise reference summary of applicable research for SEL managers.

Decker, William; Hendrick, Robert; Valett, Jon D.

1991-01-01

457

Engineering of Services and Business Models for Grid Applications  

NASA Astrophysics Data System (ADS)

In the context of using grid applications in medicine and bioinformatics a combination of classic biomedical services like the analysis of biomaterial with grid services is quite common. Services for customers in those fields need to comprise both and offer an easy way to use these combined services. Within the German project Services@MediGRID, methods for the systematic development of complex customer services including the use of grid applications are developed. In coordination with this service engineering approach for grid applications, commercial business models are derived for a set of biomedical grid services.

Falkner, Jürgen; Weisbecker, Anette

458

Performance mapping of a 30 cm engineering model thruster  

NASA Technical Reports Server (NTRS)

A 30 cm thruster representative of the engineering model design has been tested over a wide range of operating parameters to document performance characteristics such as electrical and propellant efficiencies, double ion and beam divergence thrust loss, component equilibrium temperatures, operational stability, etc. Data obtained show that optimum power throttling, in terms of maximum thruster efficiency, is not highly sensitive to parameter selection. Consequently, considerations of stability, discharge chamber erosion, thrust losses, etc. can be made the determining factors for parameter selection in power throttling operations. Options in parameter selection based on these considerations are discussed.

Poeschel, R. L.; Vahrenkamp, R. P.

1975-01-01

459

Human performance models for computer-aided engineering  

NASA Technical Reports Server (NTRS)

This report discusses a topic important to the field of computational human factors: models of human performance and their use in computer-based engineering facilities for the design of complex systems. It focuses on a particular human factors design problem -- the design of cockpit systems for advanced helicopters -- and on a particular aspect of human performance -- vision and related cognitive functions. By focusing in this way, the authors were able to address the selected topics in some depth and develop findings and recommendations that they believe have application to many other aspects of human performance and to other design domains.

Elkind, Jerome I. (editor); Card, Stuart K. (editor); Hochberg, Julian (editor); Huey, Beverly Messick (editor)

1989-01-01

460

Mass Flow Estimation with Model Bias Correction for a Turbocharged Diesel Engine  

E-print Network

Mass Flow Estimation with Model Bias Correction for a Turbocharged Diesel Engine Tomás Polóni. Based on an augmented observable Mean Value En- gine Model (MVEM) of a turbocharged Diesel engine in the intake duct. Keywords: Diesel engine, Mass flow estimation, Bias estimation, Kalman filtering, Mean value

Johansen, Tor Arne

461

Engineering behavior of small-scale foundation piers constructed from alternative materials  

NASA Astrophysics Data System (ADS)

Testing small-scale prototype pier foundations to evaluate engineering behavior is an alternative to full-scale testing that facilitates testing of several piers and pier groups at relatively low cost. In this study, various pier systems and pier groups at one tenth scale were subjected to static vertical loading under controlled conditions to evaluate stiffness, bearing capacity, and group efficiency. Pier length, material properties and methods of installation were evaluated. Pier length to diameter ratios varied between four and eight. A unique soil pit with dimensions of 2.1 m in width, 1.5 m in length and 2.0 m in depth was designed to carry out this research. The test pit was filled with moisture conditioned and compacted Western Iowa loess. A special load test frame was designed and fabricated to provide up to 25,000 kg vertical reaction force for load testing. A load cell and displacement instrumentation was setup to capture the load test data. Alternative materials to conventional cement concrete were studied. The pier materials evaluated in this study included compacted aggregate, cement stabilized silt, cementitious grouts, and fiber reinforced silt. Key findings from this study demonstrated that (1) the construction method influences the behavior of aggregate piers, (2) the composition of the pier has a significant impact on the stiffness, (3) group efficiencies were found to be a function of pier length and pier material, (4) in comparison to full-scale testing the scaled piers were found to produce a stiffer response with load-settlement and bearing capacities to be similar. Further, although full-scale test results were not available for all pier materials, the small-scale testing provided a means for comparing results between pier systems. Finally, duplicate pier tests for a given length and material were found to be repeatable.

Prokudin, Maxim Mikhaylovich

462

Engineering the pH-responsive catalytic behavior of AuNPs by DNA.  

PubMed

Noble metal nanoparticles have attracted much interest in the heterogeneous catalysis. Particularly, efficient manipulation of the responsive catalytic properties of the metal nanoparticles is an interesting topic. In this work, a simple and efficient strategy is developed to regulate the pH-responsive catalytic activities of glucose oxidase (GOx)-mimicking gold nanoparticles (AuNPs). Four DNA strands (regulating strands) that differ slightly in sequences are used to interact non-covalently with citrate-capped AuNPs, resulting in markedly distinct pH-dependent catalytic behavior of AuNPs. This is ascribed to the characteristic pH-induced conformational change of the DNA strands that leads to the different adsorption capability to the NPs surface, as demonstrated by pH-CD profiles of the respective DNA molecules. The pH-dependent catalysis of AuNPs is also encoded with structural information of the double-stranded DNA (including regulating strands and their complementary strands) that has conformation resistant or responsive to pH change. As a result, the catalysis can be programmed into an AND gate, a XNOR gate or a NOT gate, using pH and complementary strand as the inputs, the nanoparticle activity as the output and the regulating strands as the programs. This work can be expanded by engineering the catalytic behavior of noble metal nanoparticles to respond smartly to a variety of environmental stimuli, such as metal ions or light wavelengths. These results may provide insight into understanding ligand-regulated nanometallic catalysis. PMID:24039035

Zhan, Pengfei; Wang, Jinye; Wang, Zhen-Gang; Ding, Baoquan

2014-01-29

463

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

464

Customer preference and behavior: Residential modeling framework: Final report  

SciTech Connect

This report presents a technical description of the Customer Preference and Behavior Project and the models developed to predict customer acceptance. The project team began by exploring the marketing problems facing the DSM planner: diverse customer populations; the need to predict customer acceptance for a variety of program designs by target market; and, the need for cost-effective promotion and advertising approaches. In response to these problems, the team developed a theoretical modeling framework that can predict customer acceptance of almost any DSM program configuration. The project team reviewed consumer choice theory, the data requirements for using the models, and the technical issues and problems that might occur when applying the models. While the report serves as a technical description of the Customer Preference and Behavior Project, it also can assist those just beginning to address DSM problems and those wishing to go beyond direct application of the model and data bases. 276 refs., 39 figs.

Not Available

1987-05-01

465

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

SciTech Connect

Various models for free piston Stirling engines are reviewed. Initial models were developed primarily for design purposes and to predict operating parameters, especially efficiency. More recently, however, such models have been used to predict engine stability. Free piston Stirling